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ISSUED : 21-Aug-2017 IEGP PAGE 2 OF 106

CONTENTS 1. EXECUTIVE SUMMARY 3 1.1. Project Description 3 1.2. Conclusions and Recommendations 3 2. INTRODUCTION 5 2.1. Study Aims & Objectives 5 2.2. Scope of Work 5 3. TERMINOLOGY 5 3.1. Definitions 5 3.2. Abbreviations 6 4. PROJECT DETAIL 6 4.1. Process Overview 8 4.2. Project Site / Location 16 4.3. Meteorological Data 16 5. OVERVIEW OF RA METHODOLOGY 17 6. HAZARDS ASSOCIATED WITH THE PROJECT 17 6.1. General 17 6.2. Hazards Associated with Flammable Materials 17 6.3. Hazards Associated with Toxic Materials 18 7. HAZARD IDENTIFICATION 18 7.1. Hazardous Substances 18 7.2. Modes of Failure 24 7.3. Review of Industry Incidents 25 7.4. Unit Sectionalization & Selected Failure Cases 35 8. CONSEQUENCE ANALYSIS 45 8.1. Source Term Modelling 45 8.2. Dispersion Modelling 49 8.3. Physical Effects Modelling 49 9. RISK ANALYSIS DISCUSSION 63 9.1. Ethylene Recovery Unit (ERU) 63 9.2. Ethylene Glycol Unit (EG) 75 9.3. Offsite & Utility Facility (O&U) 87 9.4. Client Cases 87 10. CONCLUSION AND RECOMMENDATIONS 99 11. GUIDELINES FOR DISASTER MANAGEMENT PLAN 103 11.1. Introduction 103 11.2. Action Plans 104 12. REFERENCE 106

ATTACHMENT - A - RA METHODOLOGY & ASSUMPTIONS ATTACHMENT - B - CONSEQUENCE ANALYSIS RESULTS ATTACHMENT - C - CONSEQUENCE ANALYSIS HAZARD CONTOURS

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1. EXECUTIVE SUMMARY

1.1. Project Description

M/s. Indian Oil Corporation Limited (IOCL) has appointed M/s. Toyo Engineering India Pvt.

Ltd. as the Project Management Consultant (PMC) for installation of Ethylene Glycol

production facilities from Front End loading (FEL) stage up to Plant commissioning and final

contract closure.

1.2. Conclusions and Recommendations

Risk analysis identified the potential hazards that are associated with process and storage

facility in the proposed facilities coming under this Project. To assess consequences based

on the realization of the identified hazards, worst-case scenarios such as catastrophic

rupture of reflux drum, accumulator, storage sphere and storage tank on fire which have

very low likelihood (low frequency of occurrence, 5 x 10-7per year), certain scenarios like

large holes with frequency of occurrence (frequency in the range of 5 x 10-5 to 5 x 10-7 per

year depending upon nominal diameter of pipeline) and medium hole like pump seal leak

(10 mm equivalent hole having frequency 3.75 x 10-4 per year) have been considered.

The study reveals that for most of the failure cases, hazard distances are limited to

plant boundary and not directly affect outside the complex. The detailed discussion

on risk analysis of the identified failure cases has been given in Section 9.

Major recommendations arising out of the Risk analysis study for this project are

summarized below.

Ethylene Recovery Unit:

H2S Gas Detectors with audio-visual alarms (beacons) to be provided in vicinity of

equipment handling H2S gas (Case ER-2).

Sufficient number of Hydrocarbon gas detectors to be provided in the vicinity of pumps

and equipment handling light hydrocarbon (ER-8).

Requirement of inventory isolation to be reviewed during detail engineering for vessels

handling large amount of hydrocarbon (ER-8, ER-11, ER-12).

Catastrophic rupture scenario of Deethylenizer Reflux drum shall be included in

Disaster Management plan.

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Ethylene Glycol Unit:

Sufficient number of Hydrocarbon gas detectors / Toxic Gas detector (EO) to be

provided in the vicinity of pumps and equipment handling light hydrocarbon e.g.

ethylene, ethylene oxide (EG-1, EG-4, EG-6, EG-7, EG-8, EG-9).

Sub-station and SRR shall be positively pressurized to avoid ingress of any HC or Toxic

gas inside these building (EG-9).

HC / Toxic Gas detector to be provided at sub-station and SRR air unit suction (EG-9).

Provide HC gas detector in vicinity of 061-V-140 for early detection of any leakage.

Vehicular movement on roads along the ethylene storage sphere should be avoided to

eliminate potential ignition source.

Offsite & Utility Facility:

Provide active / passive fire protection for Ethylene Storage Sphere as per OISD(OU-1)

Provide HC gas detector in vicinity of ethylene product transfer pump seal for early

detection of any leakage (OU-1, OU-3, OU-4).

Requirement of inventory isolation to be reviewed during detail engineering (OU-1).

Vehicular movement on South side road along the ethylene storage sphere should be

avoided to eliminate potential ignition source (OU-1, OU-3, OU-4).

Catastrophic rupture scenario of Ethylene Storage Sphere shall be included in Disaster

Management plan.

Excess flow check valve shall be provided on each loading bay (OU-8, OU-11, OU-14)

Heat detection based automatic water sprinkler system to be provided (OU12, OU-14).

Continuous presence of people E-side of property line should be discouraged (OU-5).

It is recommended to allow minimum number of vehicles at a time inside loading gantry.

This may result in longer time for gantry operations but will reduce the chances of any

possible ignition & consequent hazardous scenario and resultant risk arising, on

account of any leakage from the gantry (OU-7, OU-12, OU-15).

Creek Crossing Pipe Rack: All hydrocarbon vents and drains on headers running through the pipe rack should be

plugged-off. Regular monitoring / heath check-up of headers running through the pipe rack crossing

the creek should be carried out.

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2. INTRODUCTION

2.1. Study Aims & Objectives

This Risk Analysis identifies the potential events leading to major accident hazards and the

magnitude of safety related consequences of each event. It does not establish the

probability of the event occurring.

The objectives of this study are to:

Identify possible failure / hazards associated with the coming new facility

Assess the possible consequences of these hazards should they occur.

Suggest suitable mitigation measures to minimize frequency and the consequence of

these Hazards.

2.2. Scope of Work

The intent of the RA Study is to systematically identify all potential failure / accidents /

hazards and its consequences. Subsequently analyse the extent of damage due to such

incidents and draws suitable mitigating measures.

The scope of RA Study for Project will include the following units:

Ethylene Glycol Unit (Capacity: 357 KTPA)

Ethylene Recovery Unit (Capacity: 180 KTPA)

Offsite & Utilities

The RA Study shall be performed only for the above new facilities. Detailed assessment for

the existing facilities or integration with the existing facilities or impact of existing facilities on

new facilities is not considered within the scope. However, effect of new facilities on existing

facilities have been reviewed and analysed.

3. TERMINOLOGY

3.1. Definitions

PROJECT : PMC SERVICES FOR ETHYLENE GLYCOL

PROJECT AT PARADIP REFINERY (IEGP)

COMPANY : INDIAN OIL CORPORATION LIMITED

PMC / CONSULTANT : TOYO ENGINEERING INDIA PVT. LTD.

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3.2. Abbreviations

CCPS Center for Chemical Process Safety

C&E Cause and Effect

CIA Chemical Industries Association

DNV Det Norske Veritas

ESD Emergency Shutdown

ETA Event Tree Analysis

HAZOP Hazard and Operability Study

IMD Indian Meteorological Department

LFL Lower Flammability Limit

MSDS Material Safety Datasheet

PES Potential Explosion Site

PFD Process Flow Diagram

P&ID Piping and Instrumentation Diagram

PHAST Process Hazard Analysis Safety Tool

RA Risk Assessment

SIL Safety Integrity Level

UDM Unified Dispersion Modelling

VCE Vapor Cloud Explosion

4. PROJECT DETAIL

The project consists of Ethylene Glycol (EG) unit of capacity 357 KTPA licensed by

Scientific Design Company, Ethylene Recovery Unit (ERU) of capacity 180 KTPA, licensed

by Lummus Technology and Offsite and Utilities. The overall plot plan of EG & ERU is

shown in Figure 4.1

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Figure 4.1: Overall Plot Plan

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4.1. Process Overview

The following section summarizes the processes involved in the Ethylene Recovery Unit,

Ethylene Glycol and Offsite & Utility facilities.

4.1.1. Ethylene Recovery Unit

Ethylene Recovery Unit is licensed by ABB Lummus. A schematic diagram of the ERU is

provided in Figure 4.2

Figure 4.2 Ethylene Recovery Unit

Feed Treatment Section

The contaminants in the FCC offgas will be removed before the feed is processed in the

downstream distillation section. Feed is first sent to the lower bed of the Caustic/Water

Wash Tower (C-101) where the H2S in the feed is removed and the amount of CO2 is

reduced. Next the feed goes through a FCC Offgas Chloride Treater (R-105) via Chloride

Treater Feed KOD (V-107) to remove chlorides. After the Caustic Tower and Chloride

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Treater, the feed gets heated in Oxygen Converter Feed / Effluent Exchanger (E-107) and

Oxygen Converter Feed Heater (E-108) and goes to the FCC Offgas Oxygen Converter (R-

102 A/B). The ethylene losses in the converter will be less than or equal to 1% of the

ethylene in the feed stream.

The offgas from the Oxygen Converter is gets cooled in Oxygen Converter Feed / Effluent

Exchanger (E-107) and Oxygen Converter Effluent Air Cooler (AC-101) and routed to the

upper bed of the Caustic/Water Wash Tower (C-101) to remove any remaining acid gases.

The offgas is then chilled in Dryer Feed Chiller (E-106) before being sent to the Dryer /

Treater (R-103 A/B) to remove the water, mercaptans, ammonia and amines. Finally, the

feed goes through a Mercury Adsorber (R-201 A/B) where the mercury is removed.

Distillation Section

The treated feed is then sent to the FCC Offgas Chiller (E-201), located in the Cold Box,

where a binary refrigerant is used to chill the feed. After being chilled it is then sent to the

Demethanizer (C-201).

The Demethanizer is provided with an intercooler using binary refrigerant to minimize the

ethylene losses. In the Demethanizer the FCC offgas fed into the lower part of the tower is

contacted against a side draw stream from the Deethylenizer (C-301), which enters at the

top of the tower.

The overhead stream from the Demethanizer is used as regeneration gas for the

Dryer/Treaters and then sent to OSBL to be used as refinery fuel gas. The Demethanizer

bottoms stream is sent to the Deethylenizer (C-301). The Deethylenizer overhead is fully

condensed using binary refrigerant and produces 99.5 wt% ethylene. The liquid ethylene

product is then sent to the Offsite. A small ethylene product stream is sent to the PP plant.

The bottoms stream is sent to OSBL as C3+ Product, to the offspec LPG system. A side

draw from the Deethylenizer is sent back to the top of Demethanizer as a wash liquid, with a

portion of the side draw recovered as ethane product. A binary refrigerant consisting of

ethylene and propylene is utilized to provide the refrigeration at the necessary levels for the

process users.

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4.1.2. Ethylene Glycol Unit

The Ethylene Glycol plant is licensed by Scientific Design Company. A schematic diagram

of the EG plant is provided in Figure 4.3

Figure 4.3 Ethylene Glycol Unit

EO REACTION, EO AND CO2 Scrubbing Section

Ethylene, oxygen, and ballast gas enter from battery limits and are mixed with lean cycle

gas before entering a preheating unit (Gas-Gas Exchanger E-111). The gas mixture flows

from E-111 to the EO Reactor/Gas Coolers (R-110) where about 9.6% of the ethylene is

converted per pass. The ethylene to ethylene oxide selectivity is 91% at start-of-run (SOR).

The reactors produce ethylene oxide. The ethylene oxide is scrubbed from the EO

Reactor/Gas Coolers exit gas using lean cycle water in Wash Tower (C-115) and the rich

cycle water is sent to the EO Stripping Section. The (scrubbed) cycle gas is sent through the

CO2 Contactor Section of the Wash Tower (C-115) to remove carbon dioxide made in the

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EO Reactor/Gas Coolers. The CO2-lean gas is then recompressed back to the EO

reactor/Gas Coolers in Recycle Compressor (K-115). Boiling water on the shell side of the

multi-tubular reactors removes the heat of reaction. Water circulation through the shell side

of the reactors is by thermo-syphon action. The steam-water mixture from the reactors shell

side is sent to steam drums (V-110) where make-up boiler feed water is preheated and

steam is separated from water and sent to the 21 kg/cm2g steam header.

CO2 Removal Section

The rich carbonate solution from the Carbonate Solution Exchanger (E-117) is regenerated

at essentially atmospheric pressure using stripping steam. The regenerated lean carbonate

solution is returned to the CO2 Contactor Section of the Wash Tower (C-115) for CO2

absorption.

EO Stripping and EO Reabsorption Section

Rich cycle water containing ethylene oxide in solution is preheated in Cycle water exchanger

(E-312) before entering the Stripping Column (C-310) where ethylene oxide is stripped out.

The lean cycle water is then pumped through a series of heat exchangers (E312 & E-

313A~F) where the water is cooled prior to being returned to the Scrubber Section of the

Wash Tower using Cycle Water Pump (P-312 A/B). A bleed stream is taken and sent to the

glycol unit to purge the glycol made in the cycle water loop. The ethylene oxide in the

overhead vapor from the Stripping Column (C310) is reabsorbed by contact with cooled

process water in the Re-absorber (C-320). The overhead from the Re-absorber is

compressed back into the cycle gas system by the Reclaim Compressor (K-320) while the

bottoms are sent to the Glycol Feed Stripper (C-510).

Glycol Reaction and Glycol Evaporation Section

Ethylene oxide solution from the Re-absorber (C-320) is sent to the Glycol Feed Stripper (C-

510) for removal of CO2 .The CO2 -free stream is then preheated in series of exchanger (E-

520~E523) and fed to the Glycol Reactor (R-520). The reactor effluent is fed into the first

stage of a Seven Effect Evaporator System. The cycle water bleed from the cycle water and

the MEG Column Condenser (E-621) blowdown are treated in a Cycle Water Treating Unit

(A-550) and then used in the evaporator system as reflux. The condensate from the

reboilers of the evaporators is used to preheat the feed to the Glycol Reactor (through pump

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P-*535A/B), and is then sent to the Recycle Water Tank (TK-540). The overhead from the

Fifth Effect Evaporator (extraction steam) is used in the Regenerator Extraction Reboiler (E-

223). The overhead vapor from the Sixth Effect Evaporator is used as stripping steam for

both the Stripping Column and Glycol Feed Stripper and also is used to re-boil the Vacuum

Effect Evaporator bottoms (E-537) and to preheat the feed to the Glycol Reactor through

First Stage Reactor Feed Heater (E-521). The overhead from the Vacuum Effect Evaporator

is condensed in Vacuum Effect Condenser (E-538) with a portion returning to the column as

reflux, another portion is used as reflux for the Drying Column (C-610) and the remainder is

sent to the Recycle Water Tank (TK-540) using Evaporator Hotwell Pump (P-537A/B) via

Recycle Water Cooler (E-540 A/B). The concentrated glycol from the Vacuum Effect

Evaporator is pumped to the Drying Column (C-610) for removal of the remaining water.

Glycol Drying and Glycol Purification Section

The crude wet glycol is dried by vacuum distillation in the Drying Column (C-610). The

Drying Column bottoms are filtered in MEG Column Feed Filter (GN-620A/B) and fed to the

MEG Column (C-620) where fiber grade monoethylene glycol product is taken as a side

stream product near the top of the column. The product is cooled in MEG Product Cooler

(E-622) and stored in the MEG Rundown Tanks (TK-640 a/B) for subsequent pumping to

OSBL storage. The MEG Column bottoms are sent to the MEG Splitter (C-630) using MEG

Column Bottoms Pump (P-620A/B) where the remaining MEG is removed from the heavier

glycols and recycled back to the Vacuum Effect Evaporator (C-537). The MEG Splitter

bottoms are filtered in DEG Column Feed Filters (GN-710 A/B) and are sent to the DEG

Column (C-710) for DEG and TEG Separation.

Glycol Drying and Glycol Purification Section

Heavy glycols from the MEG Splitter (C-630) bottoms are distilled in the DEG Column (C-

710) where the diethylene glycol (DEG) product is taken overhead. The DEG product is

cooled in DEG Product Cooler (E-712) and stored in the DEG Rundown Tanks (TK-730 A/B)

for subsequent pumping to OSBL storage. The DEG Column bottoms are then sent to the

TEG Column (C-720) for further distillation where the triethylene glycol (TEG) product is

taken overhead. The TEG product is cooled in TEG Product Cooler (E-722) and stored in

the TEG Rundown Drums (V-740 A/B) for subsequent pumping to OSBL storage. The TEG

Column bottoms, containing the polyglycols, are stored in the PEG Drum (V-750).

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4.1.3. Offsite & Utilities

Brief description of O&U systems are mentioned in the below:

Air Separation Unit (ASU)

Air separation unit is required to produce gaseous Oxygen and Nitrogen used in ER/EG

Units.

Gaseous oxygen is required as a raw material in EG process. Gaseous Nitrogen is required

as ballast gas in EG process as well as other purposes such as blanketing, purging,

regeneration, start-up operation of compressors etc.

Air is filtered to remove particulates and is then compressed in the Main Air Compressor.

After the air is compressed, it passes to the aftercooler where it is cooled with cooling water

and condensed water is removed. The saturated air then passes to the Adsorber vessels

where water vapor and carbon-dioxide are removed to prevent these components freezing

out in the cryogenic section of the plant and causing blockages. From the Adsorber, the air

then passes to the cold box. The stream leaving the Adsorber enters the main heat

exchanger, where it is cooled to around its dew point by heat exchange with the returning

product streams, and fed into the bottom of the high pressure distillation column.

To generate refrigeration for the distillation process, nitrogen from the top of the low

pressure section of the cold box is passed through an expander, where the pressure of the

gas is reduced to create refrigeration. After the cold box, the compressed, dry air is split

into oxygen and nitrogen streams by distillation at cryogenic temperatures.

Cooling Water System

The cooling water system which includes cooling towers, cooling water recirculation pump,

cooling water distribution headers and cooling water treatment facilities (viz. chemical

dosing for quality control, sulphuric acid for pH control etc.) and other auxiliary items.

Intermediate / Product Storage and Product Evacuation

Storage of Intermediate Feed/product is used to buffer production/consumption imbalance

or product off specification.

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Ethylene Storage

Ethylene product is pumped by the Ethylene product Pump (060-P-302A/B) in ERU,

bypassing FCC off Gas Chiller (060-E-201) to Ethylene Storage Spheres (207-HS-002A~D).

The spheres will be used to buffer ethylene production/consumption imbalance (MEG plant

non-operational) or product out of specification. Four ethylene storage spheres are used.

Out of four spheres, three are for on-spec ethylene storage and one is common for off-spec

ethylene storage and maintenance and inspection.

Five days storage is considered for on-spec ethylene product. Ethylene product in the tanks

is stored at ~18 kg/cm2g, -31.7 °C. The constant boil-off vapors will be sent to Deethylenizer

column (060-C-301). This shall be further verified with ERU Process Licensor (Lummus

Technology Inc.).

MEG Product Storage

MEG product from Ethylene Glycol unit is transferred to offsite MEG Storage Tanks (207-

TK-003 A~E) using MEG Product pumps. One tank is considered for maintenance, since

tank maintenance and inspection time is 3 to 6 months.

DEG Product Storage

DEG product from Ethylene glycol unit is routed to DEG Storage tank (207-TK-004 A~B)

located in offsite area. One tank is considered for maintenance, since tank maintenance and

inspection time is 3 to 6 months.

TEG Product Storage

TEG product from Ethylene glycol unit is routed to DEG Storage tank (207-TK-005 A~B)

located in offsite area. One tank is considered for maintenance, since tank maintenance

and inspection time is 3 to 6 months.

Product Evacuation Tanker Loading Gantries will be used for road tanker loading of finished liquid products. Top loading of the

tanker is considered for non-pressurized filling and bottom loading is considered for

pressurized filling. Loading will be done through mass flowmeters (all 7 bays).

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Ship Loading

Ship loading is considered only for MEG Product Evacuation. New line for MEG Product

Transfer from storage to south jetty is to be considered for ship loading of MEG

product. It will be dedicated line for MEG product only. Dedicated pumps (with

standby) shall be considered for ship loading of the MEG product. New loading arm for

loading MEG Product in the ship is to be considered at south jetty. Loading arm

capacity shall match with the maximum loading rate i.e. 1000 x 1.1 m3/hr.

Barrel Filling Facility

Automated barrel filling (Barrel size: 200 let.) facility provided for TEG product in offsite

area.

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4.2. Project Site / Location

The project is located in Paradip, Odisha, India as shown in Figure 4.4

4.3. Meteorological Data

Refer Assumption A5 of document “RA Study Methodology & Assumptions” (Doc. No.:

IEPG-6351-8110-PH-000-0013 Rev A2) for Meteorological data considered for the study.

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5. OVERVIEW OF RA METHODOLOGY

The key elements of RA Study comprise the following steps:

System Definition

Hazard Identification

Consequence Analysis

The RA methodology & assumptions are detailed in document “RA Study Methodology &

Assumptions” (Doc. No.: IEPG-6351-8110-PH-000-0013 Rev A2) as attached in Annexure

A.

6. HAZARDS ASSOCIATED WITH THE PROJECT

6.1. General

As this is a preliminary risk assessment hence it is primarily concerned with the impact of

the project on the surrounding environment and population. Discussion of hazardous events

will focus on those materials that will be present in quantities large enough to cause

potential problems outside the site, if a release occurs.

The main hazards will arise from the loss of containment of pressurized liquids or gases. A

loss of containment of liquid hydrocarbons has the potential to cause a pool fire, a jet fire or

a vapour cloud explosion. Gaseous hydrocarbons, though, do not result in pool fires

although they too are liable to giving rise to jet fires and vapour cloud explosions.

6.2. Hazards Associated with Flammable Materials

The units under this project contain numerous flammable streams, which on release could

result in a flammable hazard. This release could result in:

Jet Fire (ignited release)

Flash Fire (unignited release)

Vapor Cloud Explosion

Boiling Liquid Expanding Vapor Explosion (BLEVE)

Pool Fire

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6.3. Hazards Associated with Toxic Materials

The unit under this project contains potentially toxic streams, which on release could result

in a toxic hazard. These releases also pose a flammable hazard. On release toxic hazards

can cause physiological effects, dependant on the concentration and duration of exposure.

7. HAZARD IDENTIFICATION

Hazard identification involves a review of the hazardous properties of the material processed

and / or stored at the plant, review of major accidents worldwide at similar facilities. Based

on this review, a comprehensive list of potential loss of containment sources was generated

as a basis for subsequent consequence analysis.

7.1. Hazardous Substances

7.1.1. Hydrogen

Hydrogen (H2) is very light and rises very rapidly in air at normal temperature and pressure.

It is highly flammable (burns with an almost invisible flame of relatively low thermal radiation)

and explosive. It has the widest range of flammable concentrations in air among all common

gaseous fuels. This flammable range of Hydrogen varies from 4% by volume (lower

flammable limit) to 75% by volume (upper flammable limit). Hydrogen flame (or fire) is nearly

invisible even though the flame temperature is higher than that of hydrocarbon fires and

hence poses greater hazards to persons in the vicinity.

Hydrogen is biologically inactive and essentially non-toxic, hydrogen is a simple asphyxiant.

Hydrogen is not listed in the IARC, NTP or OSHA as a carcinogen or potential carcinogen.

Exposure to high concentrations may exclude an adequate supply of oxygen to the lungs.

No significant effect to human through dermal absorption and ingestion is reported. Refer to

Table 7.1 for properties of hydrogen. Constant exposure of certain types of ferritic steels to

hydrogen results in the embrittlement of the metals. Leakage can be caused by such

embrittlement in pipes, welds, and metal gaskets.

Table-7.1: Hazardous Properties of Hydrogen

S. No. Properties Values 1. LFL (%v/v) 4 2. UFL (%v/v) 75 3. Auto ignition temperature (°C) 520 4. Heat of combustion (Kcal/Kg) 28700 5. Normal Boiling point (°C) -252 6. Flash point (°C) N.A.

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7.1.2. Methane

Methane in form of liquid or gas is extremely flammable. The liquid will rapidly boil to the

gas at standard temperatures and pressures. The liquefied gas can cause frostbite to any

contaminated tissue. As a gas, if venting or leaks, catches fire. The gas is lighter than air

and may spread long distances from leak source, creating an explosive re-ignition hazard.

Vapours can be ignited by pilot lights, other flames, smoking, sparks, heaters, electrical

equipment, static discharge, or other ignition sources at locations distant from product

handling point. Explosive atmospheres may linger. Refer to Table 7.2 for properties of

methane.

Methane is essentially non-toxic. Methane acts as a simple asphyxiant and present

significant health hazard by displacing the oxygen in the atmosphere.

Table: 7.2: Hazardous properties of Methane S. No. Properties Values

1. LFL (%v/v) 5.0 2. UFL (%v/v) 15.0 3. Auto ignition temperature (°C) 630 4. Normal Boiling point (°C) -161.5 5. Flash Point (°C) -187.8

Potential Hazardous Effects – Flammable

7.1.3. Ethane

Ethane is extremely flammable gas. If venting or leaks, catches fire. The flammable

vapours may spread from leak source, creating an explosive re-ignition hazard. Vapours can

be ignited by pilot lights, other flames, smoking, sparks, heaters, electrical equipment, static

discharge, or other ignition sources at locations distant from product handling point.

Explosive atmospheres may linger. Refer to Table 7.3 for properties of ethane.

Table: 7.3: Hazardous properties of Ethane

S. No. Properties Values 1. LFL (%v/v) 3.0 2. UFL (%v/v) 12.5 3. Auto ignition temperature (°C) 472 4. Normal Boiling point (°C) -88 5. Flash Point (°C) -135


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7.1.4. Propane

A spillage or loss of containment of this hydrocarbon will result in a highly flammable

Vapour. Propane forms an explosive air-vapour mixture at ambient temperature. Propane

vapour is heavier than air and may travel to remote place of ignition e.g. along drainage, into

basement etc. Propane liquid leak generates large volumes of flammable vapours (approx.

250:1).

Cold burns (frostbite) will result from skin / eye contact with liquid. Propane liquid release or

vapour pressure jets present a serious risk to eyes. Abuse involving wilful inhalation of high

concentration of vapour, even for short periods, can produce unconsciousness, or might

prove fatal. Inhalation may cause irritation to the nose and throat, headache, nausea,

vomiting, dizziness and drowsiness. These materials delivered, stored and used at

temperature above their flash point. In case of the fire, immediately fire brigade should be

called. If gas has ignited, should not try attempting to extinguish, but stop gas flow and allow

burning out. Every precaution must be taken to keep containers cool to avoid the possibility

of a boiling liquid expanding vapour explosion (BLEVE).

Table: 7.4: Hazardous properties of Propane

S. No. Properties Values 1. LFL (%v/v) 2.1 2. UFL (%v/v) 9.5 3. Auto ignition temperature (°C) 450 4. Normal Boiling point (°C) -42.1 5. Flash Point (°C) -104 (PMCC)


7.1.5. Propylene

Propylene is highly hazardous hydrocarbon products (due to its flammable nature) handled

in the Refinery. It is primarily a mixture of C3 hydrocarbons components, which remain in

gaseous state under atmospheric pressure and temperature. Equipment’s of Ethylene

Recovery units (i.e. vessels, columns, pumps, compressors etc.) are commonly associated

with Propylene. Refer to Table 7.5 for properties of Propylene.

Table: 7.5: Hazardous properties of Propylene S. No. Properties Values

1. LFL (%v/v) 2.0 2. UFL (%v/v) 11.0 3. Auto ignition temperature (°C) 455 4. Heat of combustion (Kcal/Kg) 11000 5. Normal Boiling point (°C) -47

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7.1.6. Ethylene

Ethylene is a colourless, flammable gas with a slightly sweet odour or a colourless,

cryogenic liquid with a slightly sweet odour. This gas acts as a simple asphyxiant and

presents a significant health hazard by displacing the oxygen in the atmosphere. The gas

may spread long distances. Distant ignition and flashback are possible. The cryogenic liquid

will rapidly boil to the gas. The liquefied gas can cause frostbite to any contaminated tissue.

Both the liquid and gas pose serious fire hazards when accidentally released. Ethylene can

undergo a violent chemical reaction at elevated temperatures. Refer to Table 7.6 for

properties of ethylene.

Table: 7.6: Hazardous properties of Ethylene S. No. Properties Values

1. LFL (%v/v) 2.7 2. UFL (%v/v) 36.0 3. Auto ignition temperature (°C) 450 4. Heat of combustion (Kcal/Kg) 11000 5. Normal Boiling point (°C) -104 6. Flash Point (°C) 136 (OC)


7.1.7. Ethylene Oxide

Ethylene Oxide is extremely flammable. It may form explosive mixtures with air and oxidizing

agents. Flammable vapours may spread from spill. Explosive atmosphere may linger.

Vapours can burn without the presence of air or oxidizing agents. ETO can decompose

violently under certain conditions. Vapour in air has very low ignition energy and is prone to

static or other low energy ignition sources.

Ethylene oxide is toxic in nature, if involved in a fire and may emit irritating and potentially

toxic fumes. Fumes and vapours may spread from leak. Vapours are heavier than air and

may collect in low spots.

Table: 7.7: Hazardous properties of Ethylene Oxide S. No. Properties Values

1. LFL (%v/v) 3 2. UFL (%v/v) 100 3. Auto ignition temperature (°C) 429 4. Normal Boiling point (°C) 10.5 5. Flash Point (°C) -20 6. IDLH (ppm) (exposure time 1800 sec) 800 (NIOSH)

Potential Hazardous Effects – Flammable, Toxic

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7.1.8. Hydrogen Sulfide (H2S)

Hydrogen sulphide release is associated mainly with Amine Regeneration section, Sour

Water Stripper and Sulphur Recovery Unit. Hydrogen sulphide is a known toxic gas and has

harmful physiological effect. Accidental release of hydrocarbons containing hydrogen

sulphide poses toxic hazards to exposed population. Prolonged exposure to hydrogen

sulphide can cause irritation in eyes, respiratory system, apnea, coma, convulsions;

conjunctivitis, eye pain, lacrimation (discharge of tears), photophobia (abnormal visual

intolerance to light), corneal vesiculation, dizziness, headache, lassitude (weakness,

exhaustion), irritability, insomnia, gastrointestinal disturbance, liquid frostbite is also

flammable and can cause substantial damages if it finds source of ignition. The hazardous

properties of H2S are listed in table below:

Table: 7.8: Hazardous properties of Hydrogen Sulfide (H2S) S. No. Properties Values

1. LFL (%v/v) 4 2. UFL (%v/v) 46 3. Auto ignition temperature (°C) 260 4. Normal Boiling point (°C) -60.4 5. Melting / Freezing Point (°C) -82.8 6. IDLH (ppm) (exposure time 1800 sec) 100 (NIOSH)

7.1.9. Carbon Dioxide

Carbon dioxide (CO2) under ambient conditions is a colourless odourless gas. At higher

concentration, it has a sharp acidic odour and can be toxic. CO2 may cause asphyxiation

when the available oxygen is displaced.

CO2 is not flammable and the major hazard associated with CO2 exposure is toxicity.

Exposure to moderate concentrations can cause headache, drowsiness, dizziness, stinging

of the nose and throat, excitation, rapid breathing and heart rate, excess salivation,

vomiting, and unconsciousness. At higher concentrations, the CO2 dissolved in the blood

lowers the pH affecting the respiratory, cardiovascular and central nervous systems.

Potential Hazardous Effects – Toxic

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7.1.10. Mono-ethylene Glycol (MEG)

MEG has a low vapour pressure and not readily evaporate from water or soil. Ethylene

glycol is a clear, colorless, odorless, involatile and hygroscopic liquid with a sweet taste. It is

somewhat viscous liquid; miscible with water.

Table: 7.9: Hazardous properties of Mon-ethylene glycol (MEG) S. No. Properties Values

1. LFL (%v/v) 3.2 2. UFL (%v/v) 15.3 3. Flash Point (°C) 111 (cc) 4. Auto ignition Temperature (°C) 398 5. Normal Boiling point (°C) 197.6 6. Melting Point (°C) -13

7.1.11. Di-ethylene Glycol (DEG)

DEG is stable at room temperature. DEG is odorless, colorless, and hygroscopic liquid with

a sweet taste and bitter aftertaste. Table: 7.10: Hazardous properties of di-ethylene glycol (DEG)

S. No. Properties Values 1. LFL (%v/v) 1.6 2. UFL (%v/v) 10.8 3. Flash Point (°C) 124 (oc) 4. Auto ignition Temperature (°C) 224 5. Normal Boiling point (°C) 244 6. Melting Point (°C) -6.5

7.1.12. Tri-ethylene Glycol (TEG)

TEG is stable at room temperature. TEG is odorless, colorless to pale yellow liquid. Very

mild, sweet odor. Mixes with alcohol. Material is hygroscopic, absorbs moisture from

surrounding air. Table: 7.11: Hazardous properties oftrii-ethylene glycol (TEG)

S. No. Properties Values 1. LFL (%v/v) 0.9 2. UFL (%v/v) 9.2 3. Flash Point (°C) 176.667 (cc) 4. Auto ignition Temperature (°C) 347 5. Normal Boiling point (°C) 285 6. Melting Point (°C) -5

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7.1.13. Ethylene dichloride (EDC)

Ethylene dichloride is a clear, colorless liquid with a sweet choloroform-like odor. The liquid

is flammable, and its vapors can form explosive mixtures with air. Table: 7.11: Hazardous properties oftrii-ethylene glycol (TEG)

S. No. Properties Values 1. LFL (%v/v) 6.2 2. UFL (%v/v) 15.9 3. Flash Point (°C) 13 (cc) 4. Auto ignition Temperature (°C) 413 5. Normal Boiling point (°C) 83.5 6. Melting Point (°C) -35.5

7.1.14. Oxygen

Oxygen is a tasteless, colorless gas, odorless. Breathing pure oxygen at high pressure

(greater than 1 atm) can sause hyperoxia. Oxygen is stable when kept isolated as a

compressed gas in cylinders.

Table: 7.11: Hazardous properties oftrii-ethylene glycol (TEG)

S. No. Properties Values 1. LFL (%v/v) None reported 2. UFL (%v/v) None reported 3. Flash Point (°C) Non flammable 4. Auto ignition Temperature (°C) - 5. Normal Boiling point (°C) -183 6. Melting Point (°C) -218.4

7.2. Modes of Failure

There are various potential sources of large leakage, which may release hazardous

chemicals and hydrocarbon materials into the atmosphere. These could be in form of gasket

failure in flanged joints, bleeder valve left open inadvertently, an instrument tubing giving

way, pump seal failure, guillotine failure of equipment / pipeline or any other source of

leakage. Operating experience can identify lots of these sources and their modes of failure.

A list of general equipment and pipeline failure mechanisms is as follows:

7.2.1. Material / Construction Defects

Incorrect selection or supply of materials of construction

Incorrect use of design codes

Weld failures

Failure of inadequate pipeline supports

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7.2.2. Pre-Operational Failures

Failure induced during delivery at site Failure induced during installation Pressure and temperature effects Overpressure Temperature expansion / contraction (improper stress analysis and support design) Low temperature brittle fracture (if metallurgy is incorrect) Fatigue loading (cycling and mechanical vibration)

7.2.3. Corrosion Failures

Internal corrosion (e.g. ingress of moisture) External corrosion Cladding / insulation failure (e.g. ingress of moisture) Cathodic protection failure, if provided

7.2.4. Failures due to Operational Errors

Human error

Failure to inspect regularly and identify any defects

7.2.5. External Impact Induced Failures

Dropped objects Impact from transport such as construction traffic Vandalism Subsidence Strong winds

7.2.6. Failure due to Fire

External fire impinging on pipeline or equipment Rapid vaporization of cold liquid in contact with hot surfaces

7.3. Review of Industry Incidents

A review of industry incidents related to Ethylene Recovery and Ethylene Glycol facilities

was carried out using well established international accident databases such as Major

Accidents Reporting System (eMARS) maintained by Major Accidents Hazards Bureau

(MAHB) and Emergency Response Notification System (ERNS) maintained by Right To

Know Network (RTK). Major accidental events with potential for personnel injury or fatality

due to fire, explosion and/or toxic release were identified and analyzed. Refer to Table 7.8

for incident reported by eMARS for various hazardous substances mentioned under Section

7.1.

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Table 7.8 Incidents reported by eMARS accident database

Date Incident Consequence Substance Involved

Fatality Injuries

23-01-2014 During the change of piping and support of a feed line of

an intermediate storage vessel for hydrochloric acid, an

explosion occurred. The flame propagated back into the

tank, causing a second explosion inside. The explosion

was caused by the unexpected presence of a

considerable amount of hydrogen in the tank which was

formed in a reaction of traces of metal powder and the

hydrochloric acid and accumulated over a period of two

months. The metal powder traces were present in the in

the feed to the storage tank due to incomplete reaction in

upstream reactor due to the lower operating temperature.

The reaction continued in the storage tank and hydrogen

thus formed accumulated at tank top.

The tank ripped open and

was catapulted into the air,

killing both workers in the

process.

Hydrogen 2 No serious injuries

were reported

01-09-2005 A fire broke out affecting the heavy fuel purification plant

of the refinery. A jet-fire was ignited, causing rupture of

the 3” hydrogen pipe and subsequently ignition of the

released hydrogen. Approximately 30 minutes later, the

fire ignited an 8" fuel pipe of the diathermic oil system

The fire was kept under

control and evolved without

noticeable changes until

consumption of the fuel once

the pipes were shut off

Hydrogen No

fatalities

were

reported

No damages to

persons have been

reported

consequent to the

accident.

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Fatality Injuries

ruptured and subsequent ignition of the product. according to the emergency

response plan which had

been activated. The fire was

extinguished in 3 hours and

40 minutes after the fire

initiated

24-06-2005 An over-dosage of natron lye in a silicon dust suspension

container raised the pH-value up to 11, producing large

amounts of hydrogen in a short time. The hydrogen

caused an extreme pressure increase in the container

which consequently burst. The expanded hydrogen ignited

immediately on contact with the atmosphere

Total destruction of plant

section, damage to adjacent

buildings and cars in

surrounding area

Hydrogen No

fatalities

were

reported

No serious injuries

were reported

12-10-2002 Leakage of about 70 m3 of distilled petroleum

intermediate and 200 Nm3 of hydrogen in

Desulphurization unit of distilled intermediate. The

initiating event was vessel rupture which led to jet flame

and pool fire. This activation of external emergency plan

controlled the events.

No further consequences

were reported.

Hydrogen No

fatalities

were

reported

No serious injuries

were reported

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Fatality Injuries

27-02-2005 Leakage in pipe of Ethylene Oxide plant. Leak at the rate

of approximately 200 kg/hr was observed resulting in loss

of 22 tons of highly flammable hydrocarbons. The leakage

took place in the curve of a METHANE pipe (situated high

above the ground) through several small holes in the pipe.

Probable cause is condensation of water in the transport

gas.

As soon as the leakage was discovered it had been

arrested by putting custom made pipeline clamp.

Afterwards extra checks were undertaken in which the

company monitors the clamp placed around the pipe.

Release of unignited

flammable hydrocarbons into

the atmosphere.

Methane

Ethane

No

fatalities

were

reported

No injuries were

reported

25-04-2015 In Steam Cracker plant, a major leak occurred as a result

of the catastrophic failure of the nuts on the studs

connecting the bonnet and the body of a 2” manual drain

valve (flange leak) in a blow-down line. The bonnet was

ejected from the valve body, creating a 2” opening in the

system to atmosphere. Approximately 45 tons highly

flammable hydrocarbons were released to atmosphere.

Release of unignited

flammable hydrocarbons into

the atmosphere.

Methane

Ethylene

No

fatalities

were

reported

No injuries were

reported

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Fatality Injuries

The system was stopped, isolated and depressurized to

flare and maintenance work was undertaken to replace

the damaged valve.

27-09-2001 Release of propane from the emergency drain valve

(globe valve not closed properly) of road tanker while

taking sample using in-house designed & constructed

adapter and house / valve assembly.

Release of 16.10 tonnes

propane to ground.

Substantial quantity of

propane went into surface

water drains and reached

the oil/water interceptors.

Propane flashed off there.

Propane No

fatalities

were

reported

No serious injuries

(minor frost burns)

were reported

16-06-2001 Saturate Gas Plant (SGP), de-ethanizer column overhead

line failure resulting in an inventory loss and release of

extremely flammable gases. A catastrophic failure

occurred on a section of pipework (ID: 6”) of SGP, at an

elbow just downstream of a water-into gas injection point.

The primary cause of the catastrophic rupture and was the

erosion / corrosion of the 6” pipe which carried the

overhead vapours from the De-ethanizer to the Heat

Released gas formed vapour

cloud which subsequently

exploded resulting in

damage to SGP structure

and damage to houses and

businesses within a 1km

radius of the site (broken

windows and cracks to

ceiling and walls).

Ethane

Propane

Butane

No

fatalities

were

reported

72 civil injuries

were reported.

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Fatality Injuries

Exchanger in the SGP. The failure occurred downstream

of, and in close proximity to, a water injection point that

was not part of the original design.

The wall thickness of overhead line had been reduced

from around 7-8mm to a minimum of 0.3mm.

01-07-2008 Flange leak of hydrocarbon pump discharge of Olefin

installation during shutdown maintenance activity resulting

in release of hydrocarbon and subsequent fire due to

nearby ignition source (dropped wrench, hammer or

others).

Burn injury to maintenance

worker.

Propane 2 No serious injuries

were reported

14-08-2003 Insufficient temperature and pressure in the de-butanizer

column which led to untreated gas accumulating in the

petrol tank forming a pocket. This gas pocket spread

outside into the recipient until it reached an ignition source

resulting in flash fire and vapour cloud explosion.

Serious damage to the

industrial plant, storage

tanks in the area, window

and roof collapse of

buildings in plant area and

affected surrounding area.

Butane and

lighters

9 10

01-01-2007 In Steam Cracker Unit, a leak on the vent hole of the cold

box housing the ethylene / ethylene heat exchanger

(insulated by pearlite). The vent hole located at a height of

Release of unignited highly

flammable gas to the

atmosphere.

Ethylene

Ethane

No

fatalities

were

No injuries were

reported

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Fatality Injuries

15 m is used to evacuate the inert nitrogen of the cold box

that functions between -40 and -50 °C under 8 to 11 bar.

72 tonnes of flammable gas were released into the air at a

rate of 60 kg/hr.

To avoid any risk of ignition or explosion, the operator has

installed 4 gas detectors, constantly measured the internal

pressure of the box, monitored the development of leaks

by video camera with a feed to the control room,

increased the vent hole from 1" to 3" after installing an

elbow on it to divert the leak from the installation, which

was then connected to a mobile flare and put into service.

Water and steam curtain systems and fire monitors were

pre-positioned in case of a major leak. Automatic shut-off

valves were installed to rapidly isolate the section

concerned and the work permits procedure was modified

to take into account the deteriorated the situation.

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Fatality Injuries

17-03-2008 Release of ethylene and subsequent fire with explosion in

a tank farm causing material damage of approx. 2000000

EUR. Also engulfed adjoining acrylonitrile tank developing

to a full scale fire.

To limit the further damage, cooling of nearby equipment

over several hours by the onsite fire brigade and external

fire brigades were carried out. Evacuation of parts of the

installation and cordoning public roads were done.

Damage to equipment and

buildings of the installation

Ethylene No

fatalities

were

reported

No injuries were

reported

24-07-2013 Leakage of hydrocarbon from propylene compressor of

the Steam Cracker. A threaded connection of ¾ inches oil

pipe ¾ on an isolation valve cracked due to a progressive

fatigue caused by vibration appeared throughout the oil

circuit. Vibration and notch effect in the thread root (a 5

mm thread emerging largely beyond the useful engaged

height which is approximately 10 mm) were the main

factors behind the rupture.

Environmental pollution due

to flaring of hydrocarbons for

48 hours during the

production process.

Propylene No

fatalities

were

reported

No injuries were

reported

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Fatality Injuries

18-06-2007

Hydrogen sulfide is separated from the refinery gas in

the absorption column with diisopropanolamine (CAS

82229-41-2). The cleaned fuel gas is conveyed into the

refinery's fuel gas network.

When the event occurred the low-level shut-down

system of the column triggered. Under normal conditions

a control valve would have closed and the column level

would have risen again. The control valve however was

blocked in open position by metal parts (column

internals) and the column level dropped to zero. The

charged diisopropanolamine was diverted entirely to the

regenerator and a gas break-through of H2S occurred

over the diisopropanolamine-regenerators towards the

Claus-plants. Both the Claus-plants and the

downstream catalytic post-combustion unit were

overcharged and the gas containing H2S was discharged

over the 175m high chimney of the cracker.

Strong odour nuisance > 1h H2S

Nil

No injuries were

reported

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Fatality Injuries

05-09-2006 Release of carbon monoxide (CO) and hydrogen sulphide

(H2S) occurred in the area where a new unit of the refinery

was under construction.

During the start up phase of the catalytic cracking unit

CR4/FCC, CO is generated during approx. 30 minutes

while the charge passes at less than 700°C through the

catalyst.

Also the H2S, which is contained in the combustion gas

generated by the oven receiving the stripping water from

the unit, is directly released to atmosphere.

Release of toxic gas to

atmosphere

CO & H2S

estimated

amount

released

(225 kg)

No

fatalities

were

reported

7 injuries were

reported.

05-01-2009 In vis-breaking unit of a refinery, while performing an

intervention on equipment which could potentially inhaled

H2S.

Inhalation of hydrogen

sulphide leading to fatality.

H2S 1 No injuries were

reported.

10-09-2002 During unloading catalyst from a blinded reactor at Claus

unit. By the end of the day one of the workers violated the

end of work order and entered the restricted area (confined

vessel) without any protection. As soon as he entered the

vessel they fell unconscious. The other two workers tried to

help him, entered the vessel without protection and suffered

the same symptoms too.

Inhalation of hydrogen

sulphide leading to fatality.

H2S & CO 3 No injuries were

reported.

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7.4. Unit Sectionalization & Selected Failure Cases

The Ethylene Recovery unit and Ethylene Glycol unit were divided into 08 and 13 sections,

respectively, for the analysis based on inventories, hazardous properties of process streams

and process conditions. The detailed plant sectionalization is graphically depicted in Figure

7.1, Figure 7.2 & Figure 7.3 and Table 7.9, Table 7.10 & Table 7.11 presents the description

and modelling conditions of the hazardous sections for ER, EG and O&U facilities

respectively. Even though some of the streams, such as steam system, BFW etc., were

identified as not posing any significant toxic or flammable hazards, these were also included

in the sections list for completeness.

A list of selected failure cases was prepared based on process knowledge, engineering

judgment, experience, past incidents associated with such facilities and considering the

general mechanisms for loss of containment. A list of cases has been identified for the RA

study based on the following.

Cases with high chance of occurrence but having low consequence:

Example of such failure cases includes two-bolt gasket leak for flanges, pump seal

failure, sample connection failure, instrument tapping failure etc. The consequence

results will provide enough data for planning routine safety exercises. This will emphasize

the area where operator's vigilance is essential.

Cases with low chance of occurrence but having high consequence:

Example includes catastrophic failure of lines, process pressure vessels, pressurized

storages etc.

This approach ensures at least one representative case of all possible types of accidental

failure events, is considered for the consequence analysis. Moreover, the list below includes

at least one accidental case comprising of release of different sorts of highly hazardous

materials handled in the refinery. Although the list does not give complete failure incidents

considering all equipment’s, units, but the consequence of a similar incident considered in

the list below could be used to foresee the consequence of that particular accident.

Also Client cases have been considered for the analysis based on their comment. Headers having hydrocarbon / toxic substance cross over the creek through pipe rack. It is to be noted that these headers do not have any flanges or instrument connections over the pipe rack. Hence leakage of flanges is ruled out. However, for consequence analysis (as a conservative approach), leak on these headers over pipe rack is considered as per Client’s requirement. The cases selected for analysis are mentioned in Table 7.12.

060C10106

0R

105

060

V1

02

060E101

060V101

060P106A/B 060P107A/B 060P108

060TK101

060

V1

07

060E107

060E108

060

R1

02A

060

R1

02B

060E114

060AC101

062C101 062C102

062T101

062

V1

01

062E101

062E104

062E101A/B

062

E1

03A

/B

062P901A/B

062E105

062P902A/B06

0R

103

A

060

R1

03B06

0R

104

060GN201A/B

060

V1

03

060

V1

04

060E110

060E111

060E201

060C201 060C301

060

E2

02

060P201A/B

060P202A/B

060

E3

04

060

v30

2

060

E3

02

060

E3

03

060E301

060v301

060P301A/B

060P302A/B

060

E2

03

060

V4

06

060

V4

06

060

V4

04

060E203

060

V4

07

060E401A~F060JS404

060

V4

02

060

V4

01

060

V4

03

060V408

060K401

060AC401

060E302

060E402A~D

Figure 7.1 ER Unit

21-Aug-2017

I3

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Figure 7.2 EG UNIT

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Figure 7.3 Offsite & Utilities Sectionalization

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Table 7.9 ER Plant Sectionalization & Selected Case list

Section Description Main Equipment Case

ID Selected Failure Cases

Process Conditions Static

Inventory

(kg)

Pressure

(kg/cm2a)

Temperature

(°C)

Mass Flowrate

(kg/h)

Phase

[Note 1]

Amine Treatment Section

DGA/Water wash Column (062-C-101), DGA

Regenerator (062-C-102), DGA Regenerator Reflux

Drum (062-V-101), DGA Regenerator Condenser (062-

E-101), DGA Storage Tank (062-T-101)

ER-01 DGA/Water wash tower overhead line instrument

tapping failure 14.1 40 56788 V 1932

ER-02 DGA Reflux drum overhead line pin hole leak 1.5 98 2309 V 2500

Caustic Water Wash

Section

Caustic/Water Wash Tower (060-C-101), Chloride

Treater Feed KOD (060-V-107), FCC Off gas chloride

Treater (060-R-105), Oxygen Converter Feed/Effluent

Exchanger (060-E-107)

ER-03 FCC Off gas Chloride treater outlet flange gasket

failure 12.3 54.8 57007.2 V 3496

Oxygen Converter

Section

Oxygen Converter Feed Heater (060-E-108), FCC Off

gas Oxygen Converter (060-R-102A/B) ER-04

FCC Off gas Oxygen Converter outlet line flange

gasket leak 11.4 266 57007.2 V 1144

Drying & Treating Section

Dryer Feed Chiller (060-E-106), Dryer Feed Gas KOD

(060-V-103), FCC Off gas Dryer / Treater (060-R-

103A/B), FCC Off gas Mercury Adsorber (060-R-104),

Mercury Adsorber Effluent Filters (060-GN-201A/B)

ER-05 Process off gas line from C-101 to Dryer feed KOD

flange leakage 10.9 54.9 56813.1 V 2945

ER-06 Mercury Absorber Effluent filter flange gasket leak 10 15.6 56173.7 V 2661

ER-07 Regeneration gas line instrument tapping failure 7.9 300 10700.7 V 452

Demethanizer Section

Demethanizer )060-C-201), Demethanizer Bottoms

Pumps (060-P-201 A/B), Demethanizer Intercooler

Circulating Pumps (060-C-202A/B), Demethanizer

Intercooler (060-E-202), Demethanizer Reboiler (060-E-

203)

ER-08 Demethanizer Bottoms Pumps seal failure 9.4 -42.7 57295.6 L 141749

ER-09 Demethanizer Intercooler Circulation pump seal

failure 10.5 -84.7 230000.2 L 77066

Deethylenizer Section

Deethylenizer (060-C-301), Deethylenizer Condenser

(060-E-301), Deethylenizer Reflux Drum (060-V-301),

Deethylenizer Side Reboiler (060-E-304) Deethylenizer

Reflux Pumps (060-P-301A/B), Ethylene Product Pumps

(060-P-302A/B), C3+ Product Cooler (060-E-303)

ER-10 Deethylenizer overhead line instrument tapping

failure 17.9 -33.5 128185.7 V 28073

ER-11 Ethylene Product pump seal failure 46.5 -31.7 22596.2 L 7705

ER-12 Deethylenizer bottom line flange gasket leak 18.6 51.4 4866.2 L 6624

ER-13 Catastrophic rupture of Deethylenizer Reflux Drum 17.2 -35 - L 7309

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Inventory

(kg)

Pressure

(kg/cm2a)

Temperature

(°C)

Mass Flowrate

(kg/h)

Phase

[Note 1]

Binary Refrigerant

Section

FCC Off gas Chiller (060-E-201), Heavy Binary

Refrigerant Accumulator (060-V-404), Medium Binary

Refrigerant Accumulator (060-V-405), Light Binary

Refrigerant Accumulator (060-V-406), Binary Refrigerant

Vent Drum (060-V-407)

ER-14 Catastrophic Rupture of Light Binary Refrigerant

Accumulator 26.1 -1 - L 813

Binary Refrigerant

Compressor Section

Binary Refrigerant Compressor (060-K-401)

ER-15

Binary Refrigerant Compressor discharge

instrument tapping failure 28.4 83.7 310000 V 5355

Table 7.10 EG Plant Sectionalization & Selected Case list




Inventory

(kg)

Pressure

(kg/cm2a)

Temperature

(°C)

Mass Flowrate

(kg/h)

Phase

[Note 1]

Ethylene Oxide Reaction

Section

Sulfur Guard Bed (061-R-150), Ethylene Filters (061-GN-

150A/B), Oxygen Mixing Station Sparger (061-M-110),

Gas-Gas Exchanger (061-E-111), Reactor (061-R-110)

EG-01 Ethylene Filters flange gasket leak 26 35 22500 V 1127

EG-02 Reactor Feed line instrument tapping failure 22.37 57 981000 V 49480

EG-03 Reactor Outlet line flange gasket leak 20.33 90 981000 V 40710

Ethylene Oxide & CO2

Scrubbing Section

Wash Tower (061-C-115), Wash Tower Feed / Bottom

Exchanger (061-E-115), Recycle Gas Compressor (061-

K-115)

EG-04 Recycle Compressor Instrument tapping failure 22.52 59 939865 V 23840

CO2 Removal Section Regenerator / Regenerator Feed Flash Drums (061-C-

220) EG-05 Ballast line flange gasket leak 26 45 39.9 V 1230

Ethylene Oxide Stripping

Section

Cycle Water Exchanger (061-E-312), Stripping Column /

Flash Drum (061-C-310), Stripping Column Condenser

(061-AC-311), Acid Scrubber (061-C-311)

EG-06 Acid Scrubber outlet flange gasket leakage 1.28 51 34727 V 552

EG-07 Pin hole leak at inlet of Stripping Column

Condenser (Toxic Release) 1.48 97 58550.6 V 1230

Ethylene Oxide Re-

absorber Section

Reabsorber (061-C-320), Reclaim Compressor KOD

(061-V-320), Reclaim Compressor (061-K-320) EG-08

Flange gasket leak in Reclaim Compressor

discharge 24 127 1483.6 V 630

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Inventory

(kg)

Pressure

(kg/cm2a)

Temperature

(°C)

Mass Flowrate

(kg/h)

Phase

[Note 1]

Glycol Reaction Section

Glycol Feed Stripper (061-C-510), Reactor Feed Pumps

(061-P-510A/B), Reactor Feed Preheater (061-E-520),

First Stage Reactor Feed Heater (061-E-521), Second

Stage Reactor Feed Heater (061-E-522), Third Stage

Reactor Feed Heater (061-E-523), Glycol Reactor (061-

R-520)

EG-09 Glycol Feed Stripper overhead line instrument

tapping failure 1.28 51 1138 V 323

Glycol Evaporation

Section

First Effect Evaporator (061-C-531), Second Effect

Evaporator (061-C-532), Third Effect Evaporator (061-C-

533), Fourth Effect Evaporator (061-C-534), Fifth Effect

Evaporator (061-C-535), Sixth Effect Evaporator (061-C-

536), Vacuum Effect Evaporator (061-C-537),

Concentrated Glycol Pumps (061-P-530A/B)

EG-10 Concentrated Glycol Pump seal failure 1.29 91 54159 L 135400

Glycol Drying Section Drying Column (061-C-610), Drying Column Bottoms

Pumps (061-P-610A/B) EG-11 Drying Column Bottoms pumps seal failure 1.17 162 48749 L 92940

MEG Purification &

Product Section

MEG Column (061-C-620), MEG Column Bottoms Pumps

(061-P-620A/B), MEG Column Product Pumps (061-P-

622A/B), MEG Post treatment Resin Bed (061-V-640),

MEG Product Transfer Pumps (061-P-640A/B), MEG

Rundown Tanks (061-TK-640A/B),

EG-12 50 mm hole on MEG Column overhead line 95 mmHg 139 68858.5 V 22.07

EG-13 MEG Column Bottoms pumps seal failure 0.5 164 4977 L 46210

EG-14 MEG Procut Transfer Pump seal failure 6.5 48 41504 L 5633

MEG Splitter Section MEG Splitter (061-C-630), MEG Splitter Bottoms Pumps

(061-P-630 A/B) EG-15

MEG Splitter Bottoms Pump discharge instrument

tapping failure 7.45 175 3163 L 16440

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Inventory

(kg)

Pressure

(kg/cm2a)

Temperature

(°C)

Mass Flowrate

(kg/h)

Phase

[Note 1]

DEG Purification &

Product Section

DEG Column (061-C-710), DEG Column Bottoms Pumps

(061-P-710 A/B), DEG Column Reflux Pumps (061-P-711

A/B), DEG Rundown Tanks (061-TK-730 A/B), DEG

Product Transfer Pumps (061-P-730 A/B)

EG-16 DEG Column Bottoms Pumps seal failure 6.6 178 203 L 7023

EG-17 DEG Product Transfer Pump discharge instrument


TEG Purification &

Product Section

TEG Column (061-C-720), TEG Column Bottoms Pumps

(061-P-720 A/B), TEG Column Reflux Pumps (061-P-721

A/B), TEG Rundown Drums (061-V-740 A/B), TEG

Product Transfer Pumps (061-P-740 A/B)

EG-18 TEG Product Transfer Pump discharge instrument


Moderator Injection

System Moderator Feed Drum (061-V-140) EG-19 Moderator Feed Drum line rupture 24.5 40 - L 1836

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Table 7.11 Offsite & Utilities Selected Case list




Inventory

(kg)

Pressure

(kg/cm2a)

Temperature

(°C)

Mass Flowrate

(kg/h)

Phase

[Note 1]

Ethylene Storage

Ethylene Storage Sphere (207-HS-002A/B/C/D), Ethylene

BOG package (207-A-001), Ethylene Product Transfer

Pumps (207-P-002 A/B), Ethylene Product Vaporizer

(207-E-002 A/B),

OU-01 Flange gasket failure at the outlet of ethylene

sphere 19 -31.7 23420 L 1239695

OU-02 Flange gasket leak at BOG Package 19 -31.3 3376 V 10692

OU-03 Ethylene Product Transfer pump seal failure 30 -31.7 24750 L 1239696

OU-04 Ethylene vaporizer outlet line instrument tapping

failure 28 40 22500 V 635

OU-05 Catastrophic rupture of Ethylene Storage sphere 19 -31.7 - L 1239695

MEG Storage

MEG Storage Tanks (207-TK-003 A~E), MEG Product

Transfer Pump (207-P-003A~D), MEG Ship Loading

Pump (207-P-010 A/B), Loading Arm for MEG Tanker

Loading (207-Z-003A~E)

OU-06 MEG Product Transfer pump seal leak Atm 48 104500 L 4633

OU-07 MEG Ship loading pump discharge piping flange

gasket leak 4.25 48 546500 L 115831

OU-08 MEG Truck loading arm rupture 2.5 48 60150 L 28958

OU-09 MEG Tank on Fire Atm 48 - L 8047759

DEG Storage

DEG Storage Tanks (207-TK-004 A/B), DEG Product

Transfer Pump (207-P-004A/B), Loading Arm for DEG

Tanker Loading (207-Z-004A/B)

OU-10 DEG Product Transfer pump seal leak Atm 48 60500 L 2072

OU-11 DEG Truck loading arm rupture 2.5 48 60500 L 14572

OU-12 DEG Tank on Fire Atm 48 - L 2490400

TEG Storage

TEG Storage Tanks (207-TK-005 A/B), TEG Product

Transfer Pump (207-P-005A/B), Loading Arm for TEG

Tanker Loading (207-Z-005)

OU-13 TEG Product Transfer pump seal leak Atm 48 60500 L 2072

OU-14 TEG Truck loading arm rupture 2.5 48 60500 L 14572

OU-15 TEG Tank on Fire Atm 48 - L 349800

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Table 7.12 Client Cases

Section Description Case


Process Conditions

Static Inventory (kg) Pressure

(kg/cm2a)

Temperature

(°C) Mass Flowrate (kg/h)

Phase

[Note 1]

Pipe Rack over Creek

CC-01 C3+ Product header from ERU to PRU rupture 17.5 40 4866.2 L 3309

CC-02 50 mm hole on Refinery Off gas header from FCC to ERU 13.1 40 56788.0 V 6557

CC-03 50 mm hole on Fuel Gas header from ERU to Refinery

fuel gas system 5 40 26456.6 V 1605

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8. CONSEQUENCE ANALYSIS

Consequence analysis involves the application of the mathematical, analytical and computer

models for calculation of the effects and damages subsequent to a hydrocarbon / toxic

release accident.

Computer models are used to predict the physical behaviour of hazardous incidents (size,

shape and orientation of hazard zones). The model uses below mentioned techniques to

assess the consequences of identified scenarios:

Source Term/ Discharge Modelling

Dispersion Modelling

Physical Effects Modelling

Impact Assessment

The different consequences (Flash fire, pool fire, jet fire and Explosion effects) of loss of

containment incidents depend on the sequence of events & properties of material released

leading to the either toxic vapour dispersion, fire or explosion or both.

8.1. Source Term Modelling

Source term or discharge modelling involves determination of the discharge rate, release

duration and other physical properties of the released material, such as temperature and

pressure. These estimated parameters are then set as the initial conditions for the

subsequent dispersion or fire / explosion effects modelling.

8.1.1. Hole Size

Following hole sizes were considered in this RA study for selected failure cases:

Flammable gas release:

Flange Gasket leak: 50 mm

Instrument Tapping Failure: 50 mm

Pump Seal Failure: 10 mm

Toxic material release:

For pin hole leak: 5 mm

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8.1.2. Release Rate Calculation

In the event of a catastrophic rupture of a vessel, the Instantaneous Model was used to

model the rapid release of the entire inventory, where the material in the vessel is expanded

from initial conditions to atmospheric pressure. For releases from holes in pipes/ vessels,

release rate was calculated using standard orifice type calculations based on process

conditions and leak size.

For gas releases, the pressure in the system, and hence the release rate, slowly decrease

following isolation, resulting in a time dependent release. As a conservative approach, the

calculated initial release rate was assumed constant over the release duration for such

scenarios.

For large leaks from streams (e.g. guillotine failure of pipes) downstream of pumps/

compressors, the discharge rate will be limited by the maximum allowable flow of the pumps

/ compressors, which is generally slightly higher than the nominal capacity of the equipment.

For all release scenarios downstream of pumps / compressors, the release rate calculated

from PHAST 6.7 was compared with the pumping rate. If the calculated release rate

exceeds the normal pumping rate, the discharge rate was capped at 30% above the

maximum capacity of the pump / compressor to reflect performance curve characteristics as

a general approach in this study.

8.1.3. Release Duration

Release duration is another important output from the discharge modelling which is

determined by the upstream inventory and means of leak detection and isolation. The total

inventory available for release was calculated as the sum of equipment/ piping inventory and

the throughput before isolation is achieved.

It was assumed that isolation can be achieved within 10 minutes under normal conditions.

This value corresponds to typical time for human intervention for shutdown and isolation.

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Table 8.1 Summary of Source Term Modelling for Ethylene Recovery Unit

Case ID Hole Size (mm) Release Rate (kg/s) Release Duration (min)

ER-01 50 4.7 40

ER-02 5 0.83 46

ER-03 50 3.99 54

ER-04 50 2.79 60

ER-05 50 3.54 58

ER-06 50 3.48 57

ER-07 50 1.6 23

ER-08 10 0.15 60

ER-09 10 0.23 60

ER-10 50 7..67 60

ER-11 10 1.12 60

ER-12 50 9.11 14

ER-13 - - -

ER-14 - - -

ER-15 50 11.8 60

Table 8.2 Summary of Source Term Modelling for Ethylene Glycol Unit Case ID Hole Size (mm) Release Rate (kg/s) Release Duration (min)

EG-01 50 10.67 10

EG-02 50 8.3 30

EG-03 50 7.16 30

EG-04 50 8.3 44

EG-05 50 7.46 1

EG-06 50 0.363 25

EG-07 50 0.38 29

EG-08 50 8.3 2

EG-09 50 0.37 14

EG-10 10 0.87 60

EG-11 10 0.35 60

EG-12 50 0.316 2

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EG-13 10 0.53 60

EG-14 10 1.8 50

EG-15 50 51.1 6

EG-16 10 1.92 60

EG-17 50 44.17 1

EG-18 50 42.28 1

EG-19 50 64.7 <1

Table 8.3 Summary of Source Term Modelling for Offsite & Utilities Facility Case ID Hole Size (mm) Release Rate (kg/s) Release Duration (min)

OU-01 50 8.9 60

OU-02 50 8.89 21

OU-03 50 2.55 60

OU-04 50 11.38 6

OU-05 - - -

OU-06 50 0.2 60

OU-07 50 34.5 60

OU-08 50 23.4 28

OU-09 - - -

OU-10 50 0.1 60

OU-11 50 28.3 15

OU-12 - - -

OU-13 50 0.1 60

OU-14 50 28.4 15

OU-15 - - -

Table 8.4 Summary of Source Term Modelling for Client Cases


CC-01 50 49.1 <2

CC-02 50 4.38 60

CC-03 50 1.46 60

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8.2. Dispersion Modelling

Dispersion modelling involves mathematical simulation of how the released materials

disperse in the ambient atmosphere. Downwind and crosswind concentrations are

determined to find the gas cloud hazard footprint. Vapour dispersion modelling was

conducted using PHAST’s Unified Dispersion Model (UDM). The model considers the

following aspects of vapour cloud behaviour in dispersion modelling:

Continuous, instantaneous or time-varying releases

Jet, heavy-gas and passive dispersion

Elevated, touchdown and ground level dispersion

Droplet dispersion, rainout and droplet vaporization

Dispersion over land or water surfaces

8.3. Physical Effects Modelling

Physical effects modelling determine the magnitude of damage caused by exposure to fire,

heat radiation, overpressure or toxics. The possible hazardous outcomes are described as

below.

8.3.1. Flash Fire

A flash fire results from delayed ignition of a flammable vapour cloud, generated either

through vaporization directly from the release, or from vaporizing pools. The main hazards

of a flash fire being direct contact with the flame.

The area of possible direct flame contact is determined through the distance which the

Lower Flammability Limit (LFL) of the vapour cloud has travelled. All persons within the flash

fire envelop were assumed to be fatally injured. Due to the extreme short duration of a flash

fire, radiation effects are negligible.

Figure 8.1 presents the flammable gas dispersion results for selected worst cases in

Ethylene Recovery Unit, Ethylene Glycol Unit and O&U facility.

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Figure 8.1 Consequence Contours for Flammable Gas Dispersion

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8.3.2. Jet Fire

A jet fire results from immediate ignition of the flammable material from a pressurized

release. The working level heat radiation impact will vary widely depending on the angle of the flame

to the horizontal plane, which in turn mainly depends on the location of the leak. In this study, jet

fires were modelled for all pressurized releases of hydrocarbons.

Upon accidental leakage, the pressurized fluid will disperse as a jet, initially moving forward in the

spatial direction of the leak until the kinetic energy is lost and gravity slumping or lifting of the cloud

occurs, dependent upon whether the fluid is heavier or lighter than air.

The primary hazard associated with jet fires is direct flame contact and thermal radiation,

both of which were modelled using default parameters in PHAST 6.7, with release

orientation set at horizontal non-impinging.

Jet Fire results for selected worst case in Ethylene Recovery Unit, Ethylene Glycol Unit and

O&U facility are presented in Figure 8.2

Figure 8.2 Jet Fire Consequence Contours

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8.3.3. Pool Fire A liquid pool is formed during a prolonged leakage if the rate of leakage exceeds the rate of

vaporization. A pool fire results upon ignition of flammable liquid pool due to failure of

process vessel/ piping. Pool extension was modelled in PHAST as an ‘early pool fire’ which

takes into account the release rate, rainout, pool spreading and burning rates. The release

orientation was set at downward impinging for modelling of pool fires. The pool fire

dimensions were limited to the bund area or trench / ditch around each process zone if

provided.

Pool fire results for selected worst cases in Ethylene Glycol Unit and O&U facility are

presented in Figure 8.3. In Ethylene recovery unit there is no pool fire case.

Figure 8.3 Pool Fire Consequence Contours

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8.3.4. Vapor Cloud Explosion (VCE)

When a large amount of flammable vaporizing liquid or gas is rapidly released, a vapor

cloud forms and disperses in the surrounding air. If this cloud is ignited before the cloud is

diluted below its Lower Flammability Limit (LFL), a VCE or flash fire occurs. Explosion may

only occur in areas of high congestion, or confinement. Ignition in the open area may only

result in a flash fire or unconfined Vapor Cloud Explosion yielding relatively lower damaging

overpressure.

The Baker-Strehlow-Tang (BST) model in PHAST V6.7 was used in modelling the

overpressure generated from a VCE. The mass of hydrocarbon vapor within its lower and

upper flammable limits is considered to be available for explosion.

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Figure 8.5 Overpressure Contour (Total Flammable Mass)

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8.3.5. Fireball

A fireball can result from an immediate ignition of sudden release of pressurized liquid / gas

due to catastrophic rupture of pressure vessels. Ignition of the rapidly released materials will

form a ball of flame rising rapidly into the air and burning out in a short time. Fireballs may

also be caused by escalation from direct flame impingement on the vessel. Flashed vapor

from the vessel inventory was considered in modelling of fireball scenarios. For this study,

fireball scenario was modelled only for equipment where significant concentrations of

hydrogen or natural gas are present.

The thermal radiation level over distance from the fireball for catastrophic rupture of Light

binary refrigerant accumulator of Ethylene recovery unit is presented in Figure 8.6.

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Figure 8.6 Thermal Radiation Level Vs Distances from Fireball for Light binary

refrigerant accumulator Rupture

8.3.6. Toxic Gas Dispersion

Following a loss of containment scenario involving toxic substances such as H2S, Ethylene

Oxide (EO) the resulting toxic gas cloud may disperse long distances from the source and

cause fatalities. It may also pose significant hazard of toxic / asphyxiation to any personnel

present in close proximity to the release source. Figure 8.7 present the selected worst case

for toxic gas dispersion modelling in EG Unit

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Figure 8.7 Toxic Gas Dispersion Distance

EG-6 Acid scrubber outlet flange gasket leakage

8.3.7. Summary of Hazardous Outcomes

The hazardous outcomes considered for each scenario is presented in Table 8.5, Table 8.6,

Table 8.7 and Table 8.8 for the Ethylene Recovery Unit, Ethylene Glycol Unit, O&U facility

and Client Cases respectively. The following abbreviations are used in the tables:

JF: Jet Fire

PF: Pool Fire

FB: Fireball

FF: Flash Fire

VCE: Vapour Cloud Explosion

TX: Toxic Gas Dispersion

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Table 8.5 Physical Effects Modelling Summary for Ethylene Recovery Unit

Case ID Failure Case Description Leak Size (mm)

FF JF FB TX VCE PF

ER-01 DGA/Water wash tower overhead line instrument

tapping failure 50 Y Y - - Y -

ER-02 DGA Reflux drum overhead line pin hole leak 50 - - - Y - -

ER-03 FCC Off gas Chloride treater outlet flange gasket

failure 50 Y Y - - Y -

ER-04 FCC Off gas Oxygen Converter outlet line flange

gasket leak 50 Y Y - - Y -

ER-05 Process off gas line from C-101 to Dryer feed

KOD flange leakage 50 Y Y - - Y -

ER-06 Mercury Absorber Effluent filter flange gasket

leak 50 Y Y - - Y -

ER-07 Regeneration gas line instrument tapping failure 50 Y Y - - - -

ER-08 Demethanizer Bottoms Pumps seal failure 50 Y Y - - - -

ER-09 Demethanizer Intercooler Circulation pump seal

failure 50 Y Y - - - -

ER-10 Deethylenizer overhead line instrument tapping


ER-11 Ethylene Product pump seal failure 50 Y Y - - Y -

ER-12 Deethylenizer bottom line flange gasket leak 50 Y Y - - Y -

ER-13 Catastrophic rupture of Deethylenizer Reflux

Drum 50 Y - Y - Y -

ER-14 Catastrophic Rupture of Light Binary Refrigerant

Accumulator 50 Y - Y - Y -

ER-15 Binary Refrigerant Compressor discharge

instrument tapping failure 50 Y Y - - Y -

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Table 8.6 Physical Effects Modelling Summary for Ethylene Glycol Unit


FF JF FB TX VCE PF

EG-01 Ethylene Filters flange gasket leak 50 Y Y - - Y -

EG-02 Reactor Feed line instrument tapping failure 50 Y Y - - - -

EG-03 Reactor Outlet line flange gasket leak 50 Y Y - - - -

EG-04 Recycle Compressor Instrument tapping failure 50 Y Y - - - -

EG-05 Ballast line flange gasket leak 50 Y Y Y - Y -

EG-06 Acid Scrubber outlet flange gasket leakage 50 Y Y - Y - -

EG-07 Pin hole leak at inlet of Stripping Column

Condenser (Toxic Release) 50 Y Y - Y - -

EG-08 Flange gasket leak in Reclaim Compressor

discharge 50 Y Y - - Y -

EG-09 Glycol Feed Stripper overhead line instrument

tapping failure 50 Y Y - Y - -

EG-10 Concentrated Glycol Pump seal failure 50 Y Y - - Y Y

EG-11 Drying Column Bottoms pumps seal failure 50 Y Y - - - Y

EG-12 50 mm hole on MEG Column overhead line 50 Y Y - - - Y

EG-13 MEG Column Bottoms pumps seal failure 50 Y Y - - - Y

EG-14 MEG Procut Transfer Pump seal failure 50 Y Y - - - Y

EG-15 MEG Splitter Bottoms Pump discharge instrument

tapping failure 50 Y Y - - Y Y

EG-16 DEG Column Bottoms Pumps seal failure 50 Y Y - - Y Y

EG-17 DEG Product Transfer Pump discharge

instrument tapping failure 50 Y Y - - - Y

EG-18 TEG Product Transfer Pump discharge

instrument tapping failure 50 Y Y - - Y Y

EG-19 Moderator Feed Drum flange line rupture 50 Y Y - - Y Y

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Table 8.7 Physical Effects Modelling Summary for Offsite & Utilities Facility


FF JF FB TX VCE PF

OU-01 Flange gasket failure at the outlet of ethylene

sphere 50 Y Y - - Y -

OU-02 Flange gasket leak at BOG Package 50 Y Y - - Y -

OU-03 Ethylene Product Transfer pump seal failure 50 Y Y - - Y -

OU-04 Ethylene vaporizer outlet line instrument tapping


OU-05 Catastrophic rupture of Ethylene sphere 50 Y - Y - Y -

OU-06 MEG Product Transfer pump seal leak 50 Y - - - - Y

OU-07 MEG Ship loading pump discharge piping flange

gasket leak 50 Y - - Y Y

OU-08 MEG Truck loading arm rupture 50 Y - - - Y

OU-09 MEG Tank on Fire 50 Y - - - Y Y

OU-10 DEG Product Transfer pump seal leak 50 Y - - - - Y

OU-11 DEG Truck loading arm rupture 50 Y - - - - Y

OU-12 DEG Tank on Fire 50 Y - - - Y Y

OU-13 TEG Product Transfer pump seal leak 50 Y - - - - Y

OU-14 TEG Truck loading arm rupture 50 Y - - - - Y

OU-15 TEG Tank on Fire 50 Y - - - Y Y

Table 8.8 Physical Effects Modelling Summary for Client Cases


FF JF FB TX VCE PF

CC-01 C3+ Product header from ERU to PRU rupture 50 Y Y - - Y -

CC-02 50 mm hole on Refinery Off gas header from

FCC to ERU 50 Y Y - - Y -

CC-03 50 mm hole on Fuel Gas header from ERU to

Refinery fuel gas system 50 Y Y - - - -

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9. RISK ANALYSIS DISCUSSION

This section discusses the consequences of selected failure scenarios / cases as listed in

Section 7.4, Table 7.9, and Table 7.10 & Table 7.11 for ER, EG and O&U facilities

respectively. The hazard distances due to the scenarios are reported for 3D and 5D

weather conditions. The consequence analysis results are reported in tabular form for all

weather conditions, the same is attached as Annexure-B. Hazard distance contour for the

worst case of the selected scenario is attached as Annexure-C.

9.1. Ethylene Recovery Unit (ERU)

Fifteen (15) cases have been identified for modelling to assess the hazards in Ethylene

Recovery Unit. The details of these cases and the hazards are discussed in this section.

ER-1 (DGA/Water wash tower overhead line instrument tapping failure)

DGA / Water wash tower overhead contains 40.1 wt% of ethylene vapor and other

hydrocarbons. The pressure and temperature of the vapor is 13.1 kg/cm2g and 40°C

respectively. Failure of instrument tapping (hole dia.: 50 mm) is considered for the

modelling. From the outcome of the modelling, it is observed that flash fire, jet fire and VCE

will be realized. The hazard distance are summarized in below table

Weather Condition

Hazard Distances (m) Flash Fire

Jet Fire (kW/m2) Overpressure (bar) 4 12.5 37.5 0.03 0.1 0.3

3D 18 36 29 24 30 19 14

5D 17 36 30 25 30 19 14

From the above table and hazard contour Annexure-C Figure C1.1 & Figure C1.2, the flash

fire distance (LFL distance) and jet fire distance would be less and restricted within the

ethylene recovery unit.

Overpressure effect zones are contained within the ethylene recovery unit and do not impact

any buildings and therefore no specific recommendations are made.

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ER-2 (DGA Reflux drum overhead line pin hole leak)

DGA Reflux Drum is operating at 1.5 kg/cm2g and 98°C respectively. The vapor mostly

contains CO2 (96.44 wt%), some amount of H2S (0.5 wt%) gas is also present. A pin hole

leak due to corrosion is considered having equivalent hole size of 5mm to toxic gas release

is considered for the modelling. From the outcome of the modelling, it is observed that toxic

release will be realized. The hazard distance are summarized in below table

Weather Condition Toxic Distance (m) 3D 16

5D 10

From the above table and hazard contour Annexure-C Figure C1.4, the IDLH distance would

be less and gas containing H2S would be safely dispersed within the battery limit of ethylene

recovery unit. H2S gas being heavier than air it try to settle out at ground level.

From the above observation following is recommended

Provide H2S Gas Detector with audio-visual alarms (beacons) for early detection of any

leakage so as to take necessary mitigation measures.

Ensure escape sets along the escape route are available to escape from the leak

source to a safe location.

Routine inspection and preventive maintenance of equipment (DGA Regenerator

overhead, Reflux drum) and associated piping is advised so as to avoid any untoward

occurrence.



ER-3 (Caustic/Water wash tower overhead line instrument tapping failure)

Caustic/Water wash tower overhead contains hydrocarbon ethylene vapor. The pressure

and temperature of the vapor is 11.3 kg/cm2g and 54.8°C respectively. Failure of instrument

tapping (hole dia.: 50 mm) is considered for the modelling. From the outcome of the

modelling, it is observed that flash fire, jet fire and VCE will be realized. The hazard

distance are summarized in below table

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Weather Condition



3D 16 33 27 22 29 18 14

5D 15 33 28 23 29 18 14






ER-4 (FCC Off gas Oxygen Converter outlet line flange gasket failure)

FCC Off gas Oxygen Converter is normally operated at 11.3 kg/cm2g pressure and 266°C

temperature. This contains ethylene and other light hydrocarbons. Failure of its outlet

flange gasket (equivalent hole dia.: 50 mm) is considered for the modelling purpose. From

the outcome of the modelling, it is observed that flash fire, jet fire and VCE will be realized.

The hazard distance are summarized in below table

Weather Condition



3D 12 28 22 18 27 17 13

5D 11 28 23 19 26 17 13




Overpressure effect zones (Annexure-C Figure 1.10) are contained within the ethylene

recovery unit and do not impact any buildings and therefore no specific recommendations

are made.

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ER-5 (Process Off gas line from C-101 to Dryer feed KOD flange leakage)

C-101 off gas normal operating pressure and temperature is 9.9kg/cm2g and 55°C

respectively. This stream mainly contains ethylene vapor and other light hydrocarbons.

Failure of its outlet flange gasket (equivalent hole dia.: 50 mm) is considered for the

modelling purpose. From the outcome of the modelling, it is observed that flash fire, jet fire

and VCE will be realized. The hazard distance are summarized in below table

Weather Condition



3D 15 31 25 20 29 18 14

5D 14 31 26 21 28 18 14

From the above table and hazard contour Annexure-C Figure C1.11 & Figure C1.12, the

flash fire distance (LFL distance) and jet fire distance would be less and restricted within the




are made.

ER-6 (Mercury Adsorber Effluent Filter flange gasket leak)

060-R-104 effluent gas normal operating pressure and temperature is 9kg/cm2g and 16°C

respectively. This stream mainly contains ethylene vapor and other light hydrocarbons

(methane, ethane, propylene). Failure of inlet flange of filter GN-201A (equivalent hole dia.:

50 mm) is considered for the modelling purpose. From the outcome of the modelling, it is

observed that flash fire, jet fire and VCE will be realized. The hazard distance are

summarized in below table

Weather Condition



3D 15 31 25 20 29 18 14

5D 14 31 26 21 28 18 14

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are made.

ER-7 (Regeneration gas line instrument tapping failure)

FCC Off gas Dryer / Treater (060-R-103A/B) regeneration gas mainly contains methane &

ethane (44.84wt% & 27.34 wt% resp.). The normal pressure and temperature of

regeneration gas is 6kg/cm2g and 300°C (temperature during hot swiping is considered as a

conservative approach) respectively. Failure of instrument on regeneration line (equivalent

hole dia.: 50 mm) is considered for the modelling purpose. From the outcome of the

modelling, it is observed that flash fire and jet fire will be realized. The hazard distance are


Weather Condition

Hazard Distances (m) Flash Fire Jet Fire (kW/m2)

4 12.5 37.5 3D 7 21 17 8

5D 7 21 17 NR




ER-8 (Demethanizer Bottoms pump seal failure)

Fluid from Demethanizer (060-C-201) bottom at temperature -43°C and pressure

8.2kg/cm2g is pumped by means of Demethanizer bottoms pump (060-P-201A/B) at 17.5

kg/cm2g as feed to Deethylanizer (060-C-301). Failure of demethanizer bottoms pump seal

(equivalent hole dia.: 10 mm) with an average frequency of occurrence 3.75 x 10-4 per year

is considered for the modelling purpose. From the outcome of the modelling, it is observed

that flash fire and jet fire will be realized. The hazard distance are summarized in below

table

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Weather Condition


4 12.5 37.5 3D 3 8 7 5

5D 3 8 6 5



ethylene recovery unit. However considering the failure frequency of the pump seal,

following is recommended

Provide HC gas detectors near to Demethanizer bottoms pump (060-P-201A/B) seal.

Considering liquid hydrocarbon inventory in Demethanizer bottom, requirement of

suitable means of inventory isolation shall be reviewed during detail engineering.

ER-9 (Demethanizer Intercooler Circulation pump seal failure)

Fluid from Demethanizer (060-C-201) top section at temperature -84.8°C and pressure

8kg/cm2g is pumped by means of Demethanizer Intercooler Circulation pump (060-P-

202A/B) at 9.5 kg/cm2g and back to Demethanizer. Failure of demethanizer intercooler

circulation pump seal (equivalent hole dia.: 10 mm) with an average frequency of

occurrence 3.75 x 10-4 per year is considered for the modelling purpose. From the outcome

of the modelling, it is observed that flash fire and jet fire will be realized. The hazard

distance are summarized in below table

Weather Condition


4 12.5 37.5 3D 3 8 7 5

5D 3 8 6 5

From the above table and hazard contour Annexure-C Figure C1.21 & Figure C1.22 (only jet

fire of radiation intensity 4 kW/m2 is realized), the flash fire distance (LFL distance) and jet

fire distance would be less and restricted within the ethylene recovery unit. However

considering the failure frequency of pump seal, it is recommended to provide HC gas

detector near to Demethanizer Intercooler Circulation pump (060-P-202A/B) seal.

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ER-10 (Deethylenizer overhead line instrument tapping failure)

Deethylenizer in ERU operates at a pressure of 16.9 kg/cm2g and at a temperature of -

33°C. Deethylenizer overhead stream contains ethylene as a major component. Failure of

overhead line instrument tapping (equivalent hole dia.: 50 mm) is considered for the



Weather Condition



3D 52 57 46 39 107 75 62

5D 52 54 42 35 105 74 62

From the above table and hazard contour Annexure-C Figure C1.23, Figure C1.24 and

Figure C1.25, the flash fire contour (LFL distance), jet fire contours (4/12.5/37.5 kW/m2) and

similarly overpressure contour of 0.1 & 0.3 bar covers the N-E side road. Overpressure

contour of 0.03 bar, engulf BOG compressor shed of Ethylene storage sphere. However

considering that the area between ERU and Ethylene storage sphere is open and there is

no congestion or confined space, there will not be sufficient mass to cause explosion.


Provide Hydrocarbon Gas Detector in vicinity of Deethylenizer (060-C-301) for early

detection of any leakage so as to take necessary mitigation measures.

Vehicular movement on ERU N-E side road to be minimized to avoid any source of

ignition.

ER-11 (Ethylene Product Pump seal failure)

Fluid from Deethyleniizer Reflux Drum (060-V-301) at temperature -35°C and pressure 16.2

kg/cm2g is pumped by means of Ethylene Product pump (060-P-302A/B) at 45.5 kg/cm2g to

cold box and further to Ethylene Storage Spheres. Failure of Ethylene Product pump seal



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that flash fire, jet fire and VCE will be realized. The hazard distance are summarized in

below table

Weather Condition



3D 26 37 30 25 51 33 26

5D 24 35 28 23 49 32 26


flash fire distance (LFL distance) and jet fire distance would be restricted within the ethylene

recovery unit.

Overpressure effect zones (Annexure-C Figure 1.28) 0.1 and 0.3 bar is restricted within the

ethylene recovery unit. 0.03 bar overpressure contour covers some part of ER plant road

along N and E side.


Provide Hydrocarbon Gas Detectors in vicinity of Ethylene Product Transfer pump (060-

P-302A/B) for early detection of any leakage so as to take necessary mitigation

measures.

Considering liquid hydrocarbon inventory in Deethylenizer Reflux drum, requirement of


ER-12 (Deethylenizer bottom line flange gasket leak)

Fluid from Deethyleniizer Reflux Drum (060-V-301) at temperature -35°C and pressure 16.2

kg/cm2g is pumped by means of Ethylene Product pump (060-P-302A/B) at 45.5 kg/cm2g to

cold box and further to Ethylene Storage Spheres. Failure of Ethylene Product pump seal




below table

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Weather Condition



3D 30 53 42 33 70 47 38

5D 29 29 14 12 55 35 27

From the above table and hazard contour Annexure-C Figure C1.29, flash fire contour (LFL

distance) would be restricted within the ethylene recovery unit. Figure C1.30, the jet fire

contours of intensity 4 & 12.5 kW/m2 would be restricted within the ERU battery limit,

however jet fire contour of 4 kW/m2 covers N-E side road of ER unit, this may cause injury

to person if they are not able to reach to safe location within 20 sec.

Overpressure effect zones (Annexure-C Figure 1.31) 0.1 and 0.3 bar is restricted within the

ethylene recovery unit. 0.03 bar overpressure contour covers some part of ER plant road

along N and E side.


Considering liquid hydrocarbon inventory in Deethylenizer bottom, requirement of


ER-13 (Catastrophic rupture of Deethylenizer Reflux Drum)

Deethyleniizer Reflux Drum (060-V-301) operates at temperature -35°C and pressure 16.2

kg/cm2g. The case considered for modelling is catastrophic rupture of the vessel with an

average frequency of occurrence 5X10-7 per year. Although the occurrence frequency is

remote, to assess the worst possible consequence, this unlikely failure case is considered.

In the Catastrophic rupture scenario, vessel is destroyed by an impact, a crack, or some

other failure which propagates very quickly. The release is assumed to form a

homogeneous mass, expanding rapidly with no restrictions from the shattered vessel.

The instantaneous release of hydrocarbon may lead to fire ball explosion on immediate

ignition. Else the dispersing hydrocarbon vapor-air cloud may reach an ignition source and

a flash fire would occur. The hazard distance are summarized in below table

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Weather Condition


Fire Ball (kW/m2) Overpressure (bar) 4 12.5 37.5 0.03 0.1 0.3

3D 64 350 186 67 493 227 131

5D 100 350 186 67 497 230 142

From the above table and hazard contour Annexure-C Figure C1.32, flash fire contour (LFL

distance) would be within the property line. However it covers N & E side road of Ethylene

recovery unit. Figure C1.33, the radiation contours of intensity 12.5 & 37.5 kW/m2 remains

within the property line. However may hinder fire-fighting efforts. Radiation contour of 4

kW/m2 covers entire ER unit, major portion of EG unit, ethylene storage spheres & its

associated equipment, SRR, future sub-station, Fire water booster pump and would be

going outside the E side property line by 89-176 meters depending upon the wind direction.

Radiation intensity contour of 12.5 kW/m2 covers the entire ERU, some portion of EG unit,

ethylene storage sphere & its associated equipment, existing pump shed & scrap yard on E-

side of EG unit. Overpressure effect zones (Annexure-C Figure 1.34) 0.3 bar contour

would cover entire ER unit, however no occupied building would be coming in this contour.

0.1 bar contour would cover entire ER unit, some portion of EG unit, entire ethylene storage

sphere facility, existing petcoke rapid rail loading station, existing pump shed and also going

outside of property line on E-side of new facility by 17-51 meters. 0.03 bar contour would

cover entire ER unit, EG unit, ethylene storage sphere facility, existing petcoke rapid rail

loading station, existing pump shed, fire water booster pump shed, SRR, SS-1, part of Air

Separation unit and also going outside of property line on E-side of new facility by 242-321

meters.

From the above observations following is recommended

Efficiently monitor health of the vessel by

inspection of vessel internals, thickness measurement (involving techniques like

ultrasonic thickness measurement) & administering other techniques during shut-

down period.

This event shall be included in emergency response plan.

Ensure adequate numbers of Hydrocarbon Gas Detectors are provided in accordance

with OISD-116.

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Ensure availability of water spray system for equipment handling significant amount

of hydrocarbon to protect against thermal heat radiation are provided in accordance

with OISD-116.

ER-14 (Catastrophic rupture of Light Binary Refrigerant Accumulator)

Light Binary Refrigerant Accumulator (060-V-406) operates at temperature -1°C and

pressure 25.1 kg/cm2g. The case considered for modelling is catastrophic rupture of the

vessel with an average frequency of occurrence 5X10-7 per year. Although the occurrence

frequency is remote, to assess the worst possible consequence, this unlikely failure case is

considered. In the Catastrophic rupture scenario, vessel is destroyed by an impact, a crack,

or some other failure which propagates very quickly. The release is assumed to form a

homogeneous mass, expanding rapidly with no restrictions from the shattered vessel.

The instantaneous release of hydrocarbon may lead to fire ball explosion on immediate

ignition. Else the dispersing hydrocarbon vapor-air cloud may reach an ignition source and

a flash fire would occur. The hazard distance are summarized in below table

Weather Condition



3D 19 178 94 34 182 83 47

5D 24 178 94 34 207 100 60 From the above table and hazard contour Annexure-C Figure C1.35, flash fire contour (LFL

distance) would be limited within the battery limit of ethylene recovery unit.

Figure C1.36, the radiation contours of intensity 37.5 kW/m2 remains within the ethylene

recovery unit. Radiation contour of intensity 12.5 kW/m2 would cover N-E side road of ER

unit which may finder the fire-fighting efforts. Radiation contour of 4 kW/m2 would cover

entire ER unit, some portion of EG unit, entire ethylene storage spheres & its associated

equipment,

Overpressure effect zones (Annexure-C Figure 1.37) 0.3 & 0.1 bar contour would remain

within the property line. 0.03 bar contour would cover entire ER unit and may slightly go

outside the property line (1~17 meters) at E-side of ER unit. However no occupied building

would be coming within these contours.

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Efficiently monitor health of the vessel by inspection of vessel internals, thickness

measurement (involving techniques like ultrasonic thickness measurement) &

administering other techniques during shut-down period.


of hydrocarbon to protect against thermal heat radiation are provided in accordance

with OISD-116.

ER-15 (Binary Refrigerant Compressor discharge instrument tapping failure)

Binary Refrigerant compressor discharges refrigerant at a pressure of 27.4 kg/cm2g and at a

temperature of 84°C. Failure of discharge line instrument tapping (equivalent hole dia.: 50

mm) is considered for the modelling purpose. From the outcome of the modelling, it is

observed that flash fire, jet fire and VCE will be realized. The hazard distance are


Weather Condition



3D 36 58 46 36 74 49 39

5D 35 59 47 38 73 49 39


Figure C1.25, the flash fire contour (LFL distance), jet fire contours (4/12.5/37.5 kW/m2) and

overpressure contour (0.03/0.1/0.3 bar) would remain within the ethylene recovery unit.

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9.2. Ethylene Glycol Unit (EG)

EG-1(Ethylene Filter flange gasket leak)

Ethylene from Sulfur Guard Bed (061-R-150) goes through Ethylene filter (061-GN-150A/B)

with pressure and temperature is 25 kg/cm2g and 35°C respectively. This stream mainly

contains ethylene vapor coming for Ethylene recovery unit. Failure of inlet flange of filter

GN-150A (equivalent hole dia.: 50 mm) is considered for the modelling purpose. From the

outcome of the modelling, it is observed that flash fire, jet fire and VCE will be realized. The

hazard distance are summarized in below table

Weather Condition



3D 41 55 44 35 88 61 50

5D 40 55 45 36 87 60 50

From the above table and hazard contour Annexure-C Figure C2.1, Figure C2.2, flash fire

contour (LFL distance) and jet fire contours would be limited within the battery limit of

ethylene glycol unit.

Overpressure effect zones (Annexure-C Figure C2.3) 0.3 & 0.1 bar contour would remain

within the limits of EG unit. 0.03 bar contour would cover south & east side road of EG unit.

However no occupied building would be coming within these contours.

From the above observation following is recommended:

Provide HC gas detector in vicinity of sulfur guard bed and ethylene filters.

EG-2 (Reactor Feed line instrument tapping failure)

Reactor feed line operating pressure and temperature is 21.37 kg/cm2g and 57°C

respectively. This stream contains ethylene vapor. Failure of inlet line instrument tapping

(equivalent hole dia.: 50 mm) is considered for the modelling purpose. From the outcome of

the modelling, it is observed that flash fire and jet fire will be realized. The hazard distance

are summarized in below table

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Weather Condition


4 12.5 37.5 3D 7 38 30 NR

5D 7 39 32 NR


contour (LFL distance) and jet fire contours (radiation intensity of 4 & 12.5 kW/m2 would be

limited within the battery limit of ethylene glycol unit.

EG-3 (Reactor outlet line flange gasket leak)

Reactor operates at 19.33 kg/cm2g pressure and 90°C temperature. Failure of outlet line

flange gasket (equivalent hole dia.: 50 mm) is considered for the modelling purpose. From

the outcome of the modelling, it is observed that flash fire and jet fire will be realized. As


Weather Condition


4 12.5 37.5 3D 7 38 30 NR

5D 7 39 32 NR


contour (LFL distance) and jet fire contours (radiation intensity of 4 & 12.5 kW/m2) would be


EG-4 (Recycle Compressor instrument tapping failure)

Recycle compressor operates at 21.52 kg/cm2g pressure and 55°C temperature. Failure of

discharge line instrument tapping (equivalent hole dia.: 50 mm) is considered for the

modelling purpose. From the outcome of the modelling, it is observed that flash fire and jet

fire will be realized. As The hazard distance are summarized in below table

Weather Condition


4 12.5 37.5 3D 6.8 37.5 30 13

5D 6.5 38.5 31.5 14

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contour (LFL distance) and jet fire contours (radiation intensity of 4/12.5/37.5 kW/m2) would

be limited within the battery limit of ethylene glycol unit.


Provide HC gas detector at suction and discharge of Recycle Gas compressor (061-K-

115).

EG-5 (Ballast line flange gasket leak)

Ballast gas (future – methane) operates at 25 kg/cm2g pressure and 45°C temperature.

Failure of flange gasket (equivalent hole dia.: 50 mm) is considered for the modelling

purpose. From the outcome of the modelling, it is observed that flash fire, jet fire and VCE


Weather Condition



3D 27 49 39 31 54 34 27

5D 26 49 39 32 53 34 27


Figure C2.13 flash fire contour (LFL distance), jet fire contours (radiation intensity of 4

kW/m2) and overpressure contours (intensity 0.03/0.10/0.3 bar) would be limited within the

battery limit of ethylene glycol unit.

EG-6 (Acid Scrubber outlet flange gasket leak)

Acid Scrubber operates at 0.280 kg/cm2g pressure and 51°C temperature. Failure of outlet

line flange gasket (equivalent hole dia.: 50 mm) is considered for the modelling purpose.

From the outcome of the modelling, it is observed that flash fire and jet fire will be realized.

Also as the gas mainly contain ethylene oxide which is toxic in nature, IDLH contour is also

drawn for this scenario. The hazard distance are summarized in below table

Weather Condition

Hazard Distances (m) Flash Fire Jet Fire (kW/m2) Toxic Dispersion

4 12.5 37.5 IDLH (EO-800 ppm) 3D 4 11 NR NR 96

5D 4 12 10 NR 67

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From the above table and hazard contour Annexure-C Figure C2.14 and Figure C2.15, flash

fire contour (LFL distance) and jet fire contours (radiation intensity of 4 kW/m2) is small and

would be limited within the battery limit of ethylene glycol unit. Figure C2.16 shows the

toxic gas dispersion contour, this covers sub-station and satellite rack room.


Maintain positive pressure inside Sub-station and Satellite rack room. Flammable /

Toxic Gas (EO) detector shall be provided at the air suction duct of these building.

Ensure adequate number of HC gas detector / Toxic gas detector (EO) is provided

in vicinity of Ethylene oxide stripping Section.

Wind sock shall be installed at visible location.

Escape set to be provided along the escape route.

EG-7 (Pin-hole leak at inlet of Stripping Column condenser)

Stripping column overhead operates at 0.48 kg/cm2g pressure and 97°C temperature. Pin

hole leak (equivalent hole dia.: 5 mm) is considered for the modelling purpose. From the

outcome of the modelling, it is observed that flash fire and jet fire will be realized. Also as

the gas mainly contain ethylene oxide which is toxic in nature, IDLH contour is also drawn

for this scenario. The hazard distance are summarized in below table

Weather Condition


4 12.5 37.5 IDLH (EO-800 ppm) 3D 2 9 NR NR 71

5D 2 10 NR NR 59




toxic gas dispersion contour.

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Provide HC gas / Toxic gas (EO) detector in vicinity of Stripping column, Reflux

pump, Acid Scrubber. Also ensure that fire-fighting system such as water spray

system provided as per OISD-116.

Ensure escape set along the escape route is available.

EG-8 (Flange gasket leak of Reclaim Compressor discharge)

Reclaim Compressor operates at 23 kg/cm2g pressure and 127°C temperature. Failure of

discharge line flange gasket (equivalent hole dia.: 50 mm) is considered for the modelling



Weather Condition



3D 12 41 33 24 26 17 13

5D 11 42 34 26 26 17 13


Figure C2.22 flash fire contour (LFL distance), jet fire contours (radiation intensity of

4/12.5/37.5 kW/m2) and overpressure contours (intensity 0.03/0.10/0.3 bar) would be



Provide HC gas / Toxic gas (EO) detector in vicinity of Stripping column, Reflux

pump, Acid Scrubber. Also ensure that fire-fighting system such as water spray

system provided as per OISD-116.

EG-9 (Glycol Feed Stripper Overhead line instrument tapping failure)

Glycol Feed Stripper operates at 0.280 kg/cm2g pressure and 51°C temperature. Failure of

overhead line instrument tapping (equivalent hole dia.: 50 mm) is considered for the

modelling purpose. From the outcome of the modelling, it is observed that flash fire and jet

fire will be realized. Also as the gas mainly contain ethylene oxide which is toxic in nature,

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IDLH contour is also drawn for this scenario. The hazard distance are summarized in below

table

Weather Condition


4 12.5 37.5 IDLH (EO-800 ppm) 3D 4 11 NR NR 96

5D 3.5 12 10 NR 67




toxic gas dispersion contour, this covers sub-station and satellite rack room.


Maintain positive pressure inside Sub-station and Satellite rack room. Flammable /

Toxic Gas (EO) detector shall be provided at the air suction duct of these building

and near as per OISD-116

Wind sock shall be installed at visible location.

Escape set to be provided along the escape route.

EG-10 (Concentrated Glycol pump seal failure)

Fluid from Vacuum Effect Evaporator (061-C-537) bottom section at temperature 91°C and

pressure 0.29 kg/cm2g is pumped by means of Concentrated Glycol pump (061-P-530A/B)

to Drying Column (061-C-610). Failure of Concentrated Glycol pump seal (equivalent hole

dia.: 10 mm) with an average frequency of occurrence 3.75 x 10-4 per year is considered for

the modelling purpose. From the outcome of the modelling, it is observed that the released

liquid would form a pool around the point of source. The pool may catch fire in the presence

of an ignition source nearby giving rise to pool fire. Also jet fire would be realized if release

immediately catches fire. The hazard distance are summarized in below table

Weather Condition


Jet Fire (kW/m2) Pool Fire (kW/m2) 4 12.5 37.5 4 12.5 37.5

3D 4 11 9 NR 44 21 NR

5D 4 10 8 NR 46 22 NR

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fire of radiation intensity 4 & 12.5 kW/m2 is realized), the flash fire distance (LFL distance)

and jet fire distance would be less and restricted within the ethylene glycol unit.

Figure C2.28 shows contours for Pool Fire. Pool fire of intensity 4 & 12.5 kW/m2 would be

experienced, limited to Ethylene Glycol unit. However, thermal radiation of intensity 12.5

KW/m2 due to pool fire would engulf nearby process vessel in radius of 22 meters

depending upon the wind direction.

EG-11 (Drying Column bottoms pump seal failure)

Fluid from Drying Column (061-C-610) bottom section at temperature 162°C and pressure

0.17 kg/cm2g is pumped by means of Drying Column Bottom pump (061-P-610A/B) to MEG

Column (061-C-620). Failure of Drying Column Bottom pump seal (equivalent hole dia.: 10

mm) with an average frequency of occurrence 3.75 x 10-4 per year is considered for the

modelling purpose. From the outcome of the modelling, it is observed that the released




Weather Condition



3D 2 4 NR NR 34 20 11

5D 2 4 NR NR 35 23 11


fire of radiation intensity 4 kW/m2 would be realized), the flash fire distance (LFL distance)

and jet fire distance would be less and restricted within the ethylene glycol unit.

Figure C2.31 shows contours for Pool Fire. Pool fire of intensity 4,12.5, 37.5 kW/m2 would

be experienced, limited to Ethylene Glycol unit. However, thermal radiation of intensity 12.5


depending upon the wind direction.

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EG-12 (50 mm hole on MEG Column overhead line)

MEG Column overhead’s operating pressure and temperature is 0.18 kg/cm2g and 139°C

respectively. 50 mm hole on MEG Column overhead line is considered for the modelling

purpose. From the outcome of the modelling, it is observed that flash fire and jet fire will be

realized. The hazard distance are summarized in below table

Weather Condition


4 12.5 37.5 3D 3 9 NR NR

5D 2 11 NR NR From the above table and hazard contour Annexure-C Figure C2.32, Figure C2.33, flash fire

contour (LFL distance) and jet fire contours (radiation intensity of 4 kW/m2 would be less

and limited within the battery limit of ethylene glycol unit.

EG-13 (MEG Column bottoms pump seal failure)

Fluid from MEG Column (061-C-620) bottom section at temperature 162°C and pressure

0.17 kg/cm2g is pumped by means of Drying Column Bottom pump (061-P-610A/B) to MEG

Column (061-C-620). Failure of Drying Column Bottom pump seal (equivalent hole dia.: 10






Weather Condition



3D 3 8 7 NR 40 21 NR

5D 3 7 5 19 41 23 NR



ethylene glycol unit. Figure C2.36 shows contours for Pool Fire. Pool fire of intensity

4,12.5 kW/m2 would be experienced, limited to Ethylene Glycol unit. However, thermal

radiation of intensity 12.5 KW/m2 due to pool fire would engulf nearby process vessel in

radius of 23 meters depending upon the wind direction.

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EG-14 (MEG Product Transfer pump seal failure)

Fluid from MEG Column (061-C-620) upper section at temperature 48°C and pressure 5.5

kg/cm2g is pumped by means of MEG Product Transfer Pump (061-P-640A/B) to MEG

Rundown Tank (061-TK-600A/B). Failure of MEG Product Transfer pump seal (equivalent

hole dia.: 10 mm) with an average frequency of occurrence 3.75 x 10-4 per year is

considered for the modelling purpose. From the outcome of the modelling, it is observed

that the released liquid would form a pool around the point of source. The pool may catch

fire in the presence of an ignition source nearby giving rise to pool fire. The hazard distance

are summarized in below table

Weather Condition



3D 7 2 NR NR 58 28 NR

5D 7 2 NR NR 61 29 NR


flash fire distance (LFL distance) and jet fire (only 4kW/m2) distance would be less and

restricted within the ethylene glycol unit.

Figure C2.39 shows contours for Pool Fire. Pool fire of intensity 4,12.5 kW/m2 would be

experienced, limited to Ethylene Glycol unit. However, thermal radiation of intensity 12.5


depending upon the wind direction. Thermal radiation of intensity 4 kW/m2 would be

covering E-side road of EG unit which may hinder the fire-fighting activities.

EG-15 (MEG Splitter Bottoms Pump discharge instrument tapping failure)

Fluid from MEG Splitter (061-C-630) bottom section at temperature 175°C and pressure

7.45 kg/cm2g is pumped by means of MEG Splitter Bottoms Pump (061-P-630A/B) to DEG

Column (061-C-710). Failure of MEG Splitter bottoms pump discharge line instrument

tapping (equivalent hole dia.: 50 mm) is considered for the modelling purpose. From the

outcome of the modelling, it is observed that the released liquid would form a pool around

the point of source. The pool may catch fire in the presence of an ignition source nearby

giving rise to pool fire. Also jet fire would be experience if release immediately get ignition

source. The hazard distance are summarized in below table

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Weather Condition


Jet Fire (kW/m2) Pool Fire (kW/m2) Overpressure (bar) 4 12.5 37.5 4 12.5 37.5 0.03 0.1 0.3

3D 22 43 35 29 97 54 NR 48 32 26

5D 22 39 31 25 103 55 NR 48 32 26


flash fire distance (LFL distance) and jet fire distance would be restricted within the ethylene

glycol unit.

Annexure-C Figure C2.42 shows contours for Pool Fire. Pool fire of intensity 4,12.5 kW/m2

would be experienced, limited to Ethylene Glycol unit. However, thermal radiation of

intensity 12.5 KW/m2 due to pool fire would engulf nearby process vessel in radius of 55

meters depending upon the wind direction. Thermal radiation of intensity 4 kW/m2 would be

covering E-side road of EG unit which may hinder the fire-fighting activities.

From Annexure-C Figure C2.43 it can be seen that overpressure contours would be limited

to Ethylene Glycol unit. No building is coming under these contours.

EG-16 (DEG Column bottoms pump seal failure)

Fluid from DEG Column (061-C-710) bottom section at temperature 178°C and pressure 6.6

kg/cm2g is pumped by means of DEG Column Bottom pump (061-P-710A/B) to TEG

Column (061-C-720). Failure of DEG Column Bottom pump seal (equivalent hole dia.: 10




of an ignition source nearby giving rise to pool fire. Also jet fire, VCE would be realized.


Weather Condition



3D 10 7 6 6 64 32 NR - - -

5D 11 8 6 5 68 34 NR 18 14 12

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ethylene glycol unit.

Annexure-C Figure C2.46 shows contours for Pool Fire. Pool fire of intensity 4,12.5kW/m2

would be experienced, limited to Ethylene Glycol unit. However, thermal radiation of

intensity 12.5 KW/m2 due to pool fire would engulf nearby process vessel in radius of 34

meters depending upon the wind direction. Thermal radiation of intensity 4 kW/m2 would be

covering N-side road of EG unit which may hinder the fire-fighting activities.



EG-17 (DEG Product Transfer Pump discharge instrument tapping failure)

Fluid from DEG Rundown Tanks (061-TK-730A/B) operating at temperature 55°C and

atmospheric pressure is pumped by means of DEG Product Transfer Pump (061-P-730A/B)

to OSBL DEG Storage Tanks (207-TK-004A/B). Failure of DEG Product Transfer pump




of an ignition source nearby giving rise to pool fire. The hazard distance are summarized in

below table

Weather Condition



3D 13.5 3.13 NR NR 50.29 31.49 NR NR NR NR

5D 13.5 2.96 NR NR 51.38 33.14 NR NR NR NR


flash fire distance (LFL distance) and pool fire (intensity 4 / 12.5kW/m2) distance would be

restricted within the ethylene glycol unit.

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EG-18 (TEG Product Transfer Pump discharge instrument tapping failure)

Fluid from TEG Rundown Drum (061-V-740A/B) operating at temperature 164°C and

atmospheric pressure is pumped by means of TEG Product Transfer Pump (061-P-740A/B)

to OSBL TEG Storage Tanks (207-TK-005A/B). Failure of TEG Product Transfer pump




of an ignition source nearby giving rise to pool fire. Also jet fire would be experience if

release immediately get ignition source. The hazard distances are summarized in below

table. The hazard distance are summarized in below table

Weather Condition



3D 15 26.6 21 17.6 42.5 32.7 22.6 17.8 13.3 11.6

5D 16 24.4 19.0 16 43.38 34.11 22.7 18.4 13.6 11.8


Figure C2.52, the flash fire distance (LFL distance), jet fire and pool fire (intensity

4/12.5/37.5kW/m2) distance would be restricted within the ethylene glycol unit.



EG-19 (Moderator Feed Drum line rupture)

Moderator from Moderator Feed Drum (061-V-140) operating at temperature 40°C and 23.5

kg/cm2g pressure is feed to EO reactor with nitrogen pressure. V-140 outlet line rupture is

(equivalent hole dia.: 50 mm) is considered for the modelling purpose. From the outcome of

the modelling, it is observed that the released liquid would form a pool around the point of

source. The pool may catch fire in the presence of an ignition source nearby giving rise to

pool fire. Also jet fire would be experience if release immediately get ignition source. The

hazard distances are summarized in below table. The hazard distance are summarized in

below table

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Weather Condition



3D 11.7 79 64 52 173 87 38 15 12 11

5D 11.7 75 60 50 186 101 41 15 12 11


flash fire & overpressure contours would be restricted within the EG unit. Figure C2.55 &

Figure C2.56, the jet fire & pool fire (intensity 4/12.5/37.5kW/m2) distance would be

restricted within the facility. However, the contours are covering East side of road of EG

unit.

From above observation following is recommended:




9.3. Offsite & Utility Facility (O&U)

OU-1 (Flange gasket failure at the outlet of ethylene sphere)

Ethylene is stored in four ethylene storage sphere (207-HS-002A~D), 18 meters in diameter,

with a stored capacity of 3053m3. Ethylene is stored at pressure and temperature of sphere

is 18kg/cm2g and -38°C respectively. Failure of sphere outlet flange gasket failure

(equivalent hole dia.: 50 mm) having frequency of occurrence 5 x 10-5 to 5 x 10-7 per year is



below table

Weather Condition



3D 71 70 56 48 144 102 86

5D 72 66 52 43 143 101 85

From the above table and hazard contour Annexure-C Figure C3.1, Figure C3.2 and Figure

C3.3, the flash fire distance (LFL distance), jet fire and overpressure contours would be

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restricted within the ethylene storage sphere area. However, the radiation may have impact

on the adjacent spheres.


Provide active / passive fire protection for Ethylene Storage sphere as per OISD.


detection of any leakage.

Requirement of suitable means of inventory isolation shall be reviewed during detail

engineering.



OU-2 (Flange gasket leak at BOG Package)

Normally BOG compressor package will be in line during holding mode of operation of

sphere. During normal operation the vapor line from sphere will be floating with ERU unit.

Failure of BOG compressor outlet flange gasket (equivalent hole dia.: 50 mm) having

frequency of occurrence 5 x 10-5 to 5 x 10-7 per year is considered for the modelling



Weather Condition



3D 41 55 44 38 88 61 50

5D 40 52 41 34 87 60 50



restricted within the ethylene storage sphere area and no building is covered under these

contours.

OU-3 (Ethylene Product Transfer Pump seal failure)

Ethylene Product Transfer pump is used to transfer ethylene to MEG unit through Ethylene

vaporizer, with a capacity of 56 m3/hr. Failure of Ethylene Product Transfer pump seal

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(equivalent hole dia.: 10 mm) having frequency of occurrence 3.75 x 10-4 per year is



below table

Weather Condition



3D 23 34 27 23 48 32 26

5D 20 32 25 21 46 31 25



restricted within the ethylene storage sphere area and no building is covered under these

contours. However, radiation intensity of 12.5kW/m2 would be reaching to Ethylene

vaporizer structure.


Provide active / passive fire protection as per OISD-116.





OU-4 (Ethylene Vaporizer outlet line instrument tapping failure)

Ethylene vaporizer used to vaporize liquid ethylene from ethylene transfer pump. The outlet

temperature and pressure of ethylene vaporizer is 40°C and 27 kg/cm2g. Failure of ethylene

vaporizer outlet instrument tapping (equivalent hole dia.: 50 mm) is considered for the



Weather Condition



3D 43 58 45 36 91 62 51

5D 43 58 46 37 89 61 50

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From the above table and hazard contour Annexure-C Figure C3.7, the flash fire distance

(LFL distance), would be restricted within the ethylene storage sphere area. Figure C3.11

shows jet fire contours. Radiation intensity of 12.5kW/m2 covers ethylene storage sphere

depending upon the wind direction. Radiation intensity of 4kW/m2 convers South side road

of Ethylene storage area. Figure C3.12 shows overpressure contours. 0.1/0.3 bar

overpressure contours remains inside of sphere area. However, no building is covered

under these contours.


Provide active / passive fire protection as per OISD-116.





OU-5 (Catastrophic rupture of Ethylene Storage Sphere)

Ethylene is stored in four ethylene storage sphere (207-HS-002A~D), 18 meters in diameter,

with a stored capacity of 3053m3. Ethylene is stored at pressure and temperature of sphere

is 18kg/cm2g and -38°C respectively. The case considered for modelling is catastrophic

rupture of the vessel with an average frequency of occurrence 5X10-7 per year. Although

the occurrence frequency is remote, to assess the worst possible consequence, this unlikely

failure case is considered. In the Catastrophic rupture scenario, vessel is destroyed by an

impact, a crack, or some other failure which propagates very quickly. The release is

assumed to form a homogeneous mass, expanding rapidly with no restrictions from the

shattered vessel. The instantaneous release of hydrocarbon may lead to fire ball explosion

on immediate ignition. Else the dispersing hydrocarbon vapor-air cloud may reach an

ignition source and a flash fire would occur. The hazard distance are summarized in below

table

Weather Condition



3D 433 1840 1007 395 2657 1133 566

5D 680 1840 1007 395 2657 1133 566

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Figure C3.15, LFL contour covers ER, EG, Air separation units, sub-station (SS-1), SRR.

Radiation contours of intensity 37.5 kW/m2 remains within the property line. However,

4/12.5 kW/m2 radiation can go outside the property line on E-side. Overpressure contours

would be going outside the property line.


Efficiently monitor health of ethylene storage sphere by inspection of vessel

internals, thickness measurement (involving techniques like ultrasonic thickness

measurement) & administering other techniques during shut-down period.


of hydrocarbon to protect against thermal heat radiation.

Continuous presence of people just outside the E-side property line should be

discouraged.

Consider this failure scenario in formulating the Disaster Management plan.

OU-6 (MEG Product Transfer Pump seal leak)

MEG Product Transfer pump (207-P-003A~D) is used to transfer MEG to loading gantry.

Normal capacity of pump is 95 m3/hr. Failure of MEG Product Transfer pump seal



that flash fire and pool fire will be realized. The hazard distance are summarized in below

table

Weather Condition



3D 23 NR NR NR 30 19 9

5D 20 NR NR NR 31 21 9

From the above table and hazard contour Annexure-C Figure C3.16 and Figure C3.17, LFL

contour is limited to the leak source. Radiation intensity of 12.5/37.5 kW/m2 not impacting

the storage tank.

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OU-7 (Ship Loading pump discharge flange gasket leak)

MEG Ship loading pump (207-P-010A/B) is used to transfer MEG to ship loading. Normal

capacity of pump is 500 m3/hr. Failure of MEG Ship Loading pump discharge flange gasket

leak (equivalent hole dia.: 50 mm) having frequency of occurrence 5 x 10-5 to 5 x 10-7 per

year is considered for the modelling purpose. From the outcome of the modelling, it is

observed that flash fire, jet fire, pool fire and VCE will be realized. The hazard distance are


Weather Condition



3D 10 7 6 NR 183 96 NR 12 11 10

5D 10 6 6 NR 193 97 NR 13 11 10

From the above table and hazard contour Annexure-C Figure C3.18 through Figure C3.21,

LFL contour, Jet fire contour, Overpressure contour is limited to the leak source. Pool fire

contour of intensity 4/12.5kW/m2 would be realized. However, these are limited within the

property line.

OU-8 (MEG Truck Loading Arm leak)

MEG is loaded in truck tanker through 5 loading bays. Capacity of each loading bay is

55m3/hr. One shift of ten hours is considered for loading and unloading operation in a day.

Effective filling time of one tanker is 30 mins. Failure of Large hole at MEG loading bay

(equivalent hole dia.: 50 mm) having frequency of occurrence 5 x 10-5 to 5 x 10-7 per year is


that flash fire, jet fire and pool fire will be realized. The hazard distance are summarized in

below table

Weather Condition



3D 7 3.6 NR NR 115 56 NR

5D 7 3.4 NR NR 121 57 NR From the above table and hazard contour Annexure-C Figure C3.22 and Figure C3.14, LFL

contour and jet fire contour (4kw/m2) is limited to the leak source. Pool fire radiation intensity

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of 12.5 kW/m2 would impact other loading bay and also this in-circles N-side of future

benzene / Styrene loading gantry.


Provide excess flow check valve in liquid line, both on loading arm side and wagon

side.

Provide heat detection based automatic water sprinkler system.

Ensure sufficient number of fire water monitors at the gantry area covering the entire

length of the gantry for firefighting. Provide water spray system at loading bay area as

per the OISD guideline.

OU-9 (MEG Tank on Fire)

MEG is stored in five storage tanks (207-TK-003A~E), 25 meters diameter & 15 meters

height , with a nominal capacity of 7363m3 each tank. These are cone roof tanks with

nitrogen blanketing. MEG is stored at atmospheric pressure and 48°C temperature. The

case considered for modelling is MEG tank on fire with an average frequency of occurrence

5X10-7 per year. Although the occurrence frequency is remote, to evaluate the impact of the

pool fire radiation on adjacent storage tanks, this unlikely failure case is considered. From

the outcome of the modelling, it is observed that flash fire, pool fire and VCE will be realized.


Weather Condition


Pool Fire (kW/m2) Overpressure (bar) 4 12.5 37.5 0.03 0.1 0.3

3D 27 40 18 NR 44 30 25

5D 28 42 19 NR 48 32 26

As apparent from the Annexure C, Figures C3.25 through C3.27, pool fire of radiation

intensity 12.5 KW/m2, would not reaching to adjacent tank in the dyke. Also overpressure

contours are limited within the storage area.

OU-10 (DEG Product Transfer Pump seal leak)

DEG Product Transfer pump (207-P-004A/B) is used to transfer DEG to loading gantry.

Normal capacity of pump is 55m3/hr. Failure of DEG Product Transfer pump seal


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table

Weather Condition



3D 1 NR NR NR 23 16 7

5D 1 NR NR NR 24 17 7

From the above table and hazard contour Annexure-C Figure C3.18 Figure C3.29, LFL

contour is limited to the leak source. Also pool fire radiation intensity contour of 12.5/37.5

kW/m2 not reaching to storage tanks.

OU-11 (DEG Truck Loading Arm leak)

DEG is loaded in truck tanker through 1 loading bay. Capacity of loading bay is 55m3/hr.

One shift of ten hours is considered for loading and unloading operation in a day. Effective

filling time of one tanker is 30 mins. Failure of Large hole at DEG loading bay (equivalent

hole dia.: 50 mm) having frequency of occurrence 5 x 10-5 to 5 x 10-7 per year is considered

for the modelling purpose. From the outcome of the modelling, it is observed that flash fire

and pool fire will be realized. The hazard distance are summarized in below table

Weather Condition



3D 9 NR NR NR 97 47 NR

5D 9 NR NR NR 103 49 NR From the above table and hazard contour Annexure-C Figure C3.30 and Figure C3.31, LFL

contour and pool fire contour (4kw/m2) is limited to the leak source. Pool fire radiation

intensity of 4 kW/m2 would impact other persons in loading bay and also this in-circles N-

side of future benzene / Styrene loading gantry.


Provide excess flow check valve in liquid line, loading arm side

Provide heat detection based automatic water sprinkler system


length of the gantry for firefighting

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OU-12 (DEG Tank on Fire)

DEG is stored in two storage tanks (207-TK-004A/B), 15.5 meters diameter & 12 meters

height , with a nominal capacity of 2264m3 each tank. One tank will be operating. These are

cone roof tanks with nitrogen blanketing. DEG is stored at atmospheric pressure and 48°C

temperature. The case considered for modelling is DEG tank on fire with an average

frequency of occurrence 5X10-7 per year. Although the occurrence frequency is remote, to

evaluate the impact of the pool fire radiation on adjacent storage tanks, this unlikely failure

case is considered. From the outcome of the modelling, it is observed that flash fire, pool

fire and VCE will be realized. The hazard distance are summarized in below table

Weather Condition



3D 31 330 187 NR 38 33 32

5D 29 350 188 NR 29 24 22

As apparent from the Annexure C, Figures C3.32 through C3.34, LFL contour and

overpressure contours remains within the tank dyke area. Pool fire of radiation intensity

12.5 KW/m2, would be within the property line. However, this will cover the tanks in the dyke

area.



Ensure sufficient number of fire water monitors at the tank area

OU-13 (TEG Product Transfer Pump seal leak)

TEG Product Transfer pump (207-P-005A/B) is used to transfer TEG to loading gantry.

Normal capacity of pump is 55m3/hr. Failure of TEG Product Transfer pump seal




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Weather Condition



3D 1 NR NR NR 23 16 7

5D 1 NR NR NR 24 17 7

From the above table and hazard contour Annexure-C Figure C3.35 Figure C3.36, LFL

contour is limited to the leak source. Also pool fire radiation intensity contour of 12.5/37.5

kW/m2 not reaching to storage tanks.

OU-14 (TEG Truck Loading Arm leak)

TEG is loaded in truck tanker through 1 loading bay. Capacity of loading bay is 55m3/hr.

Failure of Large hole at TEG loading bay (equivalent hole dia.: 50 mm) having frequency of

occurrence 5 x 10-5 to 5 x 10-7 per year is considered for the modelling purpose. From the

outcome of the modelling, it is observed that flash fire and pool fire will be realized. The

hazard distance are summarized in below table

Weather Condition



3D 9 NR NR NR 97 47 NR

5D 9 NR NR NR 103 48 NR

From the above table and hazard contour Annexure-C Figure C3.37 and Figure C3.38, LFL

contour is limited to the leak source. Pool fire radiation intensity of 4 kW/m2 would impact

other persons in loading bay and also this in-circles N-side of future benzene / Styrene

loading gantry.


Provide excess flow check valve in liquid line, on loading arm side



length of the gantry for firefighting

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OU-15 (TEG Tank on Fire)

TEG is stored in two storage tanks (207-TK-005A/B), 7.5 meters diameter & 7.2 meters

height , with a nominal capacity of 3184m3 each tank. One tank will be operating. These are

cone roof tanks with nitrogen blanketing. TEG is stored at atmospheric pressure and 48°C

temperature. The case considered for modelling is TEG tank on fire with an average

frequency of occurrence 5X10-7 per year. Although the occurrence frequency is remote, to

evaluate the impact of the pool fire radiation on adjacent storage tanks, this unlikely failure

case is considered. From the outcome of the modelling, it is observed that flash fire, pool

fire and VCE will be realized. The hazard distance are summarized in below table

Weather Condition



3D 16 158 78 NR 12 11 10

5D 15 165 76 NR 12 11 10

As apparent from the Annexure C, Figures C3.39 through C3.41, LFL contour and

overpressure contours remains within the tank dyke area. Pool fire of radiation intensity

4/12.5 KW/m2, would be within the property line. However, this will cover the tanks in the

dyke area.


Provide heat detection based automatic water sprinkler system.

Ensure sufficient number of fire water monitors at the tank area.

9.4. Client Cases

CC-01 (C3+ Product header from ERU to PRU rupture)

C3+ Product from Deethylenizer (060-C-301) bottom is sent to Propylene Recovery Unit at a

pressure of 16.5 kg/cm2g and temperature of 40°C through 2” header on pipe rack over

creek. Rupture of C3+ Product header, having frequency of occurrence 5 x 10-7 per year is

considered for the modelling purpose as a conservative approach. From the outcome of the


distances are summarized in below table.

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Weather Condition



3D 14 28 20 NR 30 18 14

5D 13 26 18 11 28 18 14 As apparent from the Annexure C, Figures C4.1 through C4.3, LFL contour, Jet fire and

overpressure contours remains within the creek area only. Also no pool of liquid C3+

Product is possible.

CC-02 (50 mm hole on Refinery Off gas header from FCC to ERU)

Refinery Off gas from FCC is fed to Ethylene Recovery Unit at a pressure of 12.1 kg/cm2g

and temperature of 40°C through 18” header on pipe rack over creek. A 50 mm hole is

considered for the modelling purpose as a conservative approach. From the outcome of the


distances are summarized in below table.

Weather Condition



3D 16 34 24 NR 30 18 14

5D 15 34 25 NR 29 18 14 As apparent from the Annexure C, Figures C4.4 through C4.6, LFL contour, Jet fire and

overpressure contours remains within the creek area only.

CC-03 (50 mm hole on Fuel Gas header from ERU to Refinery fuel gas system)

Fuel Gas from Demethenizer (060-C-201) via 060-E-201 sent to Refinery Fuel gas system

at a pressure of 4 kg/cm2g and temperature of 40°C through 16” header on pipe rack over

creek. A 50 mm hole is considered for the modelling purpose as a conservative approach.

From the outcome of the modelling, it is observed that flash fire, jet fire and VCE will be

realized. The hazard distances are summarized in below table.

Weather Condition



3D 14 28 20 NR 30 18 14

5D 13 26 18 11 28 18 14 As apparent from the Annexure C, Figures C4.4 through C4.6, LFL contour, Jet fire and

overpressure contours remains within the creek area only.

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10. CONCLUSION AND RECOMMENDATIONS

A Risk Analysis has been carried out for the new facilities coming under Ethylene Glycol

(IEGP) Project. To assess consequences based on the realization of the identified hazards,

worst-case scenarios such as catastrophic rupture of reflux drum, accumulator, storage

sphere and storage tank on fire which have very low likelihood (low frequency of

occurrence, 5 x 10-7/year), certain scenarios like large holes with frequency of occurrence

(frequency in the range of 5 x 10-5 to 5 x 10-7 per year depending upon nominal diameter of

pipeline) and medium hole like pump seal leak (10 mm equivalent hole having frequency

3.75 x 10-4 per year) have been considered. The effect zone has been indicated for the

weather condition causing worst consequences for each failure scenario.

The study reveals that for most of the failure cases, hazard distances are limited to

plant boundary and not affecting outside the complex. The detailed discussion on

risk analysis of the identified failure cases has been given in Section 9.

Major recommendations arising out of the Risk analysis study for this project are

summarized below.

Ethylene Recovery Unit: H2S Gas Detectors with audio-visual alarms (beacons) to be provided in vicinity of

equipment handling H2S gas (Case ER-2).

Sufficient number of Hydrocarbon gas detectors to be provided in the vicinity of pumps

and equipment handling light hydrocarbon (ER-8).

Requirement of inventory isolation to be reviewed during detail engineering for vessels

handling large amount of hydrocarbon (ER-8, ER-11, ER-12).

Catastrophic rupture scenario of Deethylenizer Reflux drum shall be included in

Disaster Management plan.

Ethylene Glycol Unit: Sufficient number of Hydrocarbon gas detectors / Toxic Gas detector (EO) to be

provided in the vicinity of pumps and equipment handling light hydrocarbon e.g.

ethylene, ethylene oxide (EG-1, EG-4, EG-6, EG-7, EG-8, EG-9).

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Sub-station and SRR shall be positively pressurized to avoid ingress of any HC or Toxic

gas inside these building (EG-9).

HC / Toxic Gas detector to be provided at sub-station and SRR air unit suction (EG-9).




Offsite & Utility Facility: Provide active / passive fire protection for Ethylene Storage Sphere as per OISD(OU-1)


detection of any leakage (OU-1, OU-3, OU-4).

Requirement of inventory isolation to be reviewed during detail engineering (OU-1).


eliminate potential ignition source (OU-1, OU-3, OU-4).

Catastrophic rupture scenario of Ethylene Storage Sphere shall be included in Disaster

Management plan.

Excess flow check valve shall be provided on each loading bay (OU-8, OU-11, OU-14)

Heat detection based automatic water sprinkler system to be provided (OU12, OU-14).

Continuous presence of people E-side of property line should be discouraged (OU-5).

It is recommended to allow minimum number of vehicles at a time inside loading gantry.

This may result in longer time for gantry operations but will reduce the chances of any

possible ignition & consequent hazardous scenario and resultant risk arising, on

account of any leakage from the gantry (OU-7, OU-12, OU-15).

Creek Crossing Pipe Rack: It is to be noted that headers crossing creek over pipe rack, do not have any flanges or

instrument connections. Hence leakage of flanges / snap-off of instrument tapping is ruled

out. However, for consequence analysis (as a conservative approach), rupture / leak on

these headers over pipe rack is considered as per Client’s requirement. From the

consequence analysis it can be seen that the hazard distances due to fire, overpressure is

restricted within the creek area only. Considering these, as a prevention measure following

actions need to be taken care:

agparanjpe

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All hydrocarbon vents and drains on headers running through the pipe rack should be

plugged-off.

Regular monitoring / heath check-up of headers running through the pipe rack crossing

the creek should be carried out.

General Recommendations

Mitigating Measures

Mitigating measures are those measures in place to minimize the loss of containment event

and, hazards arising out of Loss of containment. These include:

Rapid detection of an uncommon event (HC leak, Toxic gas leak, Flame etc.) and

alarm arrangements and development of subsequent quick isolation mechanism for

major inventory.

Measures for controlling / minimization of Ignition sources inside the facility.

Active And Passive Fire Protection for critical equipment and major structures.

Effective Emergency Response plans to be in place.

Detection and isolation

Ignition Control

Ignition control will reduce the likelihood of fire events. This is the key for reducing the

risk within facilities that process flammable materials. As part of mitigation measure it

strongly recommended to consider removal of Smoking booths which are located inside

unit though they are not acting as direct source of ignition.

Proper checking of contract people for Smoking or Inflammable materials to be ensured

at entry gates to avoid presence of any unidentified source of ignition.

The vehicles entering the facility should be fitted with spark arrestors as a mandatory

item.

Escape Routes

Provide windsocks throughout the site to ensure visibility from all locations. This will

enable people to escape upwind or crosswind from flammable / toxic releases.

Sufficient escape routes from the site should be provided to allow redundancy in

escape from all areas.

Escape sets shall be provided along the escape route in the unit.

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Provide breathing apparatus at strategic locations inside the unit.

Provide sign boards marking emergency/safe roads to be taken during any exigencies.

Emergency security / evacuation drills to be organized at organization level to ensure

preparation of the personnel’s working in the complex for handling any extreme

situation.

Active and Passive Fire Protection

In order to prevent secondary incident arising from any failure scenario, it is

recommended that automatic/manual sprinklers should be provided on the large

inventory vessels and Storage Tanks/Mounded Bullets and should be regularly checked

to for their functionality.

It is to be ensured that firefighting systems for Existing/New tanks are provided as per

latest OISD guidelines.

Fire proofing of structures and vessels supports as per latest OISD guidelines to

prevent hazard escalation in the event of fire.

Preventive Maintenance for Critical Equipment

In order to further reduce the probability of catastrophes efficient monitoring of vessel

internals during shut-down to be carried out for pressurized vessels handling significant

volume of hydrocarbons, whose rupture would lead to massive consequences based

upon the outcomes of RA study.

Others

Closed sampling system to be considered for pressurized services like Ethylene etc.

Whenever a person visits for sampling and maintenance etc. it is always recommended

to carry portable HC / Toxic Gas detector.

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11. GUIDELINES FOR DISASTER MANAGEMENT PLAN

11.1. Introduction

Disasters are major accidents which cause wide spread disruption of human and

commercial activities. Normally, common accidents are absorbed by the community, but

disasters are major accidents and community cannot absorb them with their own resources.

Most of the disasters, natural or technological (man- made) have sudden onset and give

very short notice or no time to prevent the occurrence. Disasters may cause loss of human

life, injuries and long-term disablement of people working in the organization and local

community around the industrial area. Normally, loss of revenue / employment and

rebuilding cost lead to severe economic constraints.

The likelihood of disaster needs to be foreseen, as the past experiences indicate.

Therefore, if disasters are foreseeable, the mitigating efforts can be planned in advance.

Paramount importance should be given to protect human life and environment, in such

planning.

As the IOCL, Paradip facility is existing operating facility and have the disaster management

plan for the facility.

Following are the essential aspects of a conventional DMP:

Organization Structure Service coordinator

Chain of command Fire & safety coordinator

Suggested responsibilities of the members

of DMP organogram

Plant coordinator

Overall Technical coordinator Finance coordinator

Chief co-coordinator Electrical and communication coordinator

Technical coordinator Transport and Medical coordinator

Manufacturing / Production units coordinator Personnel and Welfare coordinator

Material coordinator Administration, Welfare and Security

coordinator

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11.2. Action Plans

The selected failure scenarios as analyzed in Section 9 of the report may be considered as

representative cases of failures that may lead to loss of containment.

The failures selected when realized may lead to disastrous consequences as they affect

major process units that handle large inventory of flammable or toxic material. Inability to

timely control such event may result in heavy casualty to life and property.

11.2.1. Emergency Plan for Controlling the Initial Incident

In case of release of contents to atmosphere and when there is no fire, the action plan shall

include: Report the incident to the superior officer concerned / control room.

Break the nearest fire alarm field station and / or dial the fire station giving the location

and nature of emergency.

Mobilize all firefighting resources including foam truck and DCP tender and ask them to

be ready to fight any eventuality and be near the scene.

Ambulance and medical staff to report at the scene. Remove injured personnel and

render medical treatment.

Start firewater spray to reduce vapor concentration. Care should be taken to avoid

water spray on spilled liquid.

As per wind direction, remove / isolate the ignition sources like heaters, vehicles etc.

If vapor cloud moves towards control room, air-handling (HVAC) unit is to be stopped.

In case a fire is noticed in the area, the “Fire emergency procedure” must be put into

action immediately.

Take emergency shutdown of the unit and also neighboring units.

Shut down concerned rotating equipment (e.g. pump / compressor) which is supplying

inventory to the place of incident or Isolate the nearest concerned valves to segregate

the concerned vessel.

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11.2.2. Disaster Plan

Trigger off the Emergency plan by sounding the alert system and prepare for any

emergency arising in case fire is not brought under control leading to catastrophic situation.

The emergency action plan to be initiated in case of failure would be as follows: Take an emergency shutdown of nearby process units, which are still in operation.

Depending on the nature of the severity of disaster the whole complex may have to be

shut down. Decision is to be taken by Chief co-coordinator, Overall Technical co-

coordinator and Fire and Safety Co-coordinator in consultation amongst themselves.

Operate the cooling water spray on the affected vessel/nearby vessels.

Start additional firewater pumps and maintain header pressure.

Arrange for topping up diesel in firewater pumps/DG sets.

Inject foam on the vessels under fire through foam lines using the trucks or other foam

making equipment as and where accessibility permits.

Inform ambulance and medical staff to report at the scene.

Remove injured personnel and render medical treatment. Get additional medical

help if required. Hospitalize the affected people and inform their families.

Cordon off the affected area and remove all non-essential employees (e.g. Contractor’s

personnel).

Arrange for traffic control inside the refinery and outside the main gate. Ensure

that the approach road to the main gate is cleared to facilitate movement of essential

services. Arrange for refreshments for firefighting personnel.

Arrange relief crew for firefighting personnel.

Inform neighboring people about the fire (colony and outsiders) to avoid panic among

the people.

Inform local authorities/police station. Arrange for evacuation of people.

Inform the press about the nature and seriousness of the fire to avoid false

propaganda.

Intimate concerned authorities about the situation. Obtain supplementary

materials/equipment etc. for crisis control from other places if required.

The inputs given above may be suitably updated in the existing Disaster Management Plan

(DMP) of Paradip Refinery and Petrochemical Complex.

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12. REFERENCE

[1] Climatological Normals 1961-1990 by Indian Meteorological Department

[2] UK HSE, Application of RA in Operational Safety Issues, Det Norske Veritas Ltd,

2002

[3] OGP Risk Assessment Data Directory – Ignition Probabilities, Report No. 434-6,

International Association of Oil & Gas Producers, March 2010

[4] Cox A.W., Lees F.P., Ang M.L., (1990), Classification of Hazardous Locations,

IChemE, Rugby, UK

[5] Woodward, J. L., Estimating the Flammable Mass of a Vapor Cloud, CCPS Concept

Book, AIChE

[6] Lees, F.P., Loss Prevention in the Process Industries, Butterworth-Heinemann, 1996

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RA METHODOLOGY & ASSUMPTIONS

DOC NO. : IEGP-6351-8110-RA-

000-0001, Rev-I3

ISSUED : 21-Aug-2017 IEGP PAGE A1 OF A20

ATTACHMENT - A

ASSUMPTIONS REGISTER

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ISSUED : 28-Oct-2016 IEGP PAGE 1 OF 7

CONTENTS

1. Introduction 2

2. SCOPE OF WORK 2

3. OBJECTIVE 2

4. TERMINOLOGY 2

4.1 Definitions 2

4.2 Abbreviations 3

5. RA METHODOLOGY 3

5.1 System Description 3

5.2 Hazard Identification 3

5.3 Consequence Analysis 4

5.3.1 Source term/ Discharge modelling 4

5.3.2 Dispersion Modelling 4

5.3.3 Physical effects modelling 5

5.3.4 Impact Assessment at Consequence End-Point 6

5.4 Risk Mitigation Measures 6

5.5 Guidelines for Disaster Management Plan (DMP) 6

6. DOCUMENTS REQUIRED 6

7. RA REPORT CONTENT 7

8. SOFTWARE 7

9. REFERENCE 7

ATTACHMENT – 1 - Assumptions Register

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1. Introduction M/s. Indian Oil Corporation Limited (IOCL) has appointed M/s. Toyo Engineering India Pvt. Ltd. as the Project Management Consultant (PMC) for installation of Ethylene Glycol production facilities from Front End loading (FEL) stage up to Plant commissioning and final contract closure.

2. SCOPE OF WORK The intent of the RA Study is to systematically identify all potential failure / accidents / hazards and its consequences. Subsequently analyse the extent of damage due to such incidents and draws suitable mitigating measures. The scope of RA Study for Project will include the following units: Ethylene Glycol Unit (Capacity: 357 KTPA)

Ethylene Recovery Unit (Capacity: 180 KTPA)

Offsite & Utilities

The RA Study shall be performed only for the above new facilities. Detailed assessment for the existing facilities or integration with the existing facilities or impact of existing facilities on new facilities or vice versa is not considered within the scope.

3. OBJECTIVE This Risk Analysis identifies the potential events leading to major accident hazards and the magnitude of safety related consequences of each event. It does not establish the probability of the event occurring. The objectives of this study are to: Identify possible failure / hazards associated with the coming new facility

Assess the possible consequences of these hazards should they occur.

Suggest suitable mitigation measures to minimize frequency and the consequence of these Hazards

4. TERMINOLOGY

4.1 Definitions

PROJECT : PMC SERVICES FOR ETHYLENE GLYCOL PROJECT AT PARADIP REFINERY (IEGP)

COMPANY : INDIAN OIL CORPORATION LIMITED

PMC / CONSULTANT : TOYO ENGINEERING INDIA PVT. LTD.

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4.2 Abbreviations CCPS Center for Chemical Process Safety C&E Cause and Effect CIA Chemical Industries Association DNV Det Norske Veritas ESD Emergency Shutdown ETA Event Tree Analysis HAZOP Hazard and Operability Study IMD Indian Meteorological Department LFL Lower Flammability Limit MSDS Material Safety Datasheet PES Potential Explosion Site PFD Process Flow Diagram P&ID Piping and Instrumentation Diagram PHAST Process Hazard Analysis Safety Tool RA Risk Assessment SIL Safety Integrity Level UDM Unified Dispersion Modelling VCE Vapour Cloud Explosion

5. RA METHODOLOGY A detailed procedure as given by the American Institute of Chemical Engineers Center for Chemical Process Safety (CCPS CPRA) will be adopted to conduct the RA. The key elements of this procedure are outlined in following sections.

5.1 System Description The study begins with the system definition. This involves a review of the process description, PFDs, P&IDs etc. to have a thorough understanding of the process. The process is then divided into subsections, considering process conditions, for further analysis.

5.2 Hazard Identification The RA begins with hazard identification which involves a review of the hazardous properties of the materials processed and stored at the plant. Following techniques may be employed for identification of hazards: 1. Collection of information on relevant operating conditions of proposed facilities. 2. Identification of hazard prone areas based on credible and worst case accidental release

scenarios. 3. Identification of worst case scenarios involving fire and explosion etc. on the basis of

safety feature / instrumentation provided at the station.

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5.3 Consequence Analysis Consequence modelling will be used to predict the size, shape, and orientation of hazard zones resulting from releases of flammable or toxic substances. Elements comprising the consequence analysis are described in the following sections.

5.3.1 Source Term/ Discharge Modelling Source term or discharge modelling involves determination of the maximum discharge rate, release duration and other physical properties of the released material, such as temperature and pressure. These estimated parameters are then set as the initial conditions for the subsequent dispersion or fire effects modelling. Refer Attachment -1 for Hole sizes considered in this RA Study.

Release Rate Calculation In the event of a catastrophic rupture of a vessel, the Instantaneous Model will be used to model the rapid release of the entire inventory, where the material in the vessel is expanded from initial conditions to atmospheric pressure. For releases from holes in pipes/ vessels, release rate will be calculated using standard orifice type calculations based on process conditions and leak size. For gas releases, the pressure in the system, and hence the release rate, slowly decrease following isolation, resulting in a time dependent release. As a conservative approach, the calculated initial release rate is assumed constant over the release duration for such scenarios. For large leaks from liquid streams, the release rate calculated from orifice type calculations will be compared with the pumping rate. If the calculated release rate exceeds the normal pumping rate, the discharge rate will be capped at 1.3 times the normal pumping rate. This will be applied to all leak locations downstream of a pump. Release Duration Release duration is determined by the upstream inventory and means of leak detection and isolation. The total release inventory will be calculated as the sum of equipment / piping inventory and the pump throughput before isolation is achieved. With the provision of gas and fire detectors and emergency shutdown system, it is assumed that isolation will be achieved within 2 mins. under normal conditions. It is possible for the isolation system to fail, in which case isolation can be achieved through manual intervention within 10 mins. Based on isolation system design and valves provided timing will be chosen accordingly.

5.3.2 Dispersion Modelling This involves mathematical simulation of how the released material disperses in the ambient atmosphere. Downwind and crosswind concentrations are determined to find the gas cloud hazard footprint.

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Vapour dispersion modelling will be conducted using PHAST’s Unified Dispersion Model (UDM).

5.3.3 Physical effects modelling Physical effects modelling determine the magnitude of damage caused by exposure to fire, heat radiation, overpressure or toxins. The following possible hazardous outcomes will be considered in the RA; Flash Fire A flash fire results from delayed ignition of a flammable vapour cloud, generated either through vaporization directly from the release, or from vaporizing pools. The main hazards of a flash fire being direct contact with the flame. The area of possible direct flame contact effects is determined through the distance which the lower flammability limit (LFL) of the vapour cloud has travelled. Due to the extreme short duration of a flash fire, radiation effects are negligible. Jet Fire A jet fire results from immediate ignition of the flammable material from a pressurized release. The main hazards from a jet fire are direct flame contact and radiation. Pool Fire A pool fire results upon ignition of a flammable liquid pool due to failure of process vessel/ piping. It is assumed that any liquid release shall form a pool around the source of the release. In the event of an ignition source a pool fire may ensue and shall result in a hazard due to thermal radiation. However, within the process units, Jet Fire effects will dominate and pool fires on process plant are not modelled. However, Storage Tank fires are modelled. Fireball A fireball would result from immediate ignition of a release resulting from cold catastrophic rupture of a pressurized vessel. Ignition of the rapidly released materials will form a ball of flame rising rapidly into the air and burning out in a short time. Vapour Cloud Explosion (VCE) When a flammable vapour cloud forms, disperses and accumulates in areas with high congestion or confinement, and is then ignited, a Vapour Cloud Explosion (VCE) may result. The plant will be divided into Potential Explosion Site (PES) based on the equipment layout and the Baker-Strehlow-Tang model will be used to model the overpressure generated at given distance from the PES.

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Toxic Gas Dispersion In case the released material is toxic and the cloud is dispersed without being ignited, it may cause toxic effects to exposed personnel. The aim of the toxic risk study is to determine whether the operators in the plant, people in occupied buildings and the public are likely to be affected by toxic substances. Toxic gas cloud e.g. EO Dispersion was undertaken to the Immediately Dangerous to Life and Health Concentration (IDLH) limit to determine the extent of the toxic hazard created as the result of loss of containment of a toxic substance.

5.3.4 Impact Assessment at Consequence End-Point Thermal Radiation The main hazard for jet fire, pool fire or fireball is personnel being exposed to the thermal radiation. While the fire scenario in this study is expected to last for some duration, the maximum exposure time to heat radiation is 20 seconds. The exception is fireballs which generally last less than 20s. In this case, the duration of the fireball is used as the exposure time. Refer Attachment -1 for damage criteria adopted for this study. Vapour Cloud Explosion (VCE) The primary cause for injuries or fatalities is damage to lung when expose to high overpressures. Refer Attachment -1 for damage criteria adopted for this study. Toxic Materials Refer Attachment -1 for damage criteria adopted for this study.

5.4 Risk Mitigation Measures Any mitigation measures will be recommended based on the result of the consequence analysis, towards minimization of risk identified in the study.

5.5 Guidelines for Disaster Management Plan (DMP) Based on the worst case identified in this study, guidelines for Disaster Management Plan (DMP) will be provided. IOCL to update the existing Disaster Management Plan (DMP) of Paradip Refinery.

6. DOCUMENTS REQUIRED The following documents will be required as input to the RA Study: Process Description

PFDs

Plot Plan, equipment and piping layout, and elevation drawings

ESD Philosophy

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Fire Protection Philosophy

Engineering Design Datasheets for all plant items/equipment

Heat and Mass Balance

P&IDs

Material Safety Data Sheets (MSDS)

7. RA REPORT CONTENT The RA Report will contain the following sections: Executive Summary

Introduction

Project Site and Surroundings


Consequence Analysis

Conclusion and Recommendation (Risk Mitigation Measures)

Guidelines for Disaster Management Plan (DMP)

References

Annexures including RA Study Methodology & Assumptions, rule set and / or data sources, and Conclusion assessment results.

8. SOFTWARE

The RA will be conducted using the 6.7 version of DNV PHAST.

9. REFERENCE [1] Climatological Normals 1961-1990 by Indian Meteorogical Department [2] UK HSE, Application of RA in Operational Safety Issues, Det Norske Veritas Ltd,

2002 [3] OGP Risk Assessment Data Directory – Ignition Probabilities, Report No. 434-6,

International Association of Oil & Gas Producers, March 2010 [4] Cox A.W., Lees F.P., Ang M.L., (1990), Classification of Hazardous Locations,

IChemE, Rugby, UK [5] Woodward, J. L., Estimating the Flammable Mass of a Vapor Cloud, CCPS Concept

Book, AIChE [6] Lees, F.P., Loss Prevention in the Process Industries, Butterworth-Heinemann, 1996

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ASSUMPTIONS REGISTER

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Study Assumptions The table below presents the Summary of Assumptions intended to use in RA Study for the Scope as described in Section 2. Assumption Sheet Description

Study Basis

Assumption No. A1 Drawing and Documents

Software Tools

Assumption No: A2 Risk Analysis Tool


Assumption No: A3 Representative Hole Size

Assumption No: A4 Scenario Identification

Metrological Data

Assumption No: A5 Meteorological Data

Consequence Modelling

Assumption No: A6 Isolation Time & Release Direction

Assumption No: A7 Representative Process Parameters

Assumption No: A8 Physical Effect Modelling

Assumption No: A9 Impact Criteria

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STUDY BASIS

Assumption A1 Drawing and Documents

Following documents will be referred for conducting Risk Analysis

Sr. No.

Drawing / Document Title

1 Process Description

2 Process Flow Diagram

3 Heat & Mass Balance

4 Piping & instrumentation Diagrams

5 Equipment Datasheets

6 Loss Prevention Philosophy (PDRP4280-8150-PH-0004 Rev A2)

7 Risk Analysis Report (PDRP4280-8150-RP-0001 Rev A3)

8 Risk Analysis Report Addendum to Rev A3 (PDRP4280-8150-RP-0001 Rev A4 and A5)

9 Basic Engineering Design Data

10 Overall Site Plan (PDRP4200-8230-01-600-0001 Rev S1)

11 Equipment Layout

12 Material Safety Data sheet (MSDS)

Reference:

Sr. No. 6-8 Received from Owner vide mail 16.08.2016

RE 6351-IEGP Data Required for Risk Assessment & DMP .msg

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SOFTWARE

Assumption A2 Risk Analysis Tool

The PHAST Ver. 6.7 will be used for Consequence Modelling and Risk Modelling. The

Unified Dispersion Model (UDM) is respected as one of the world’s leading dispersion models

for Process Safety applications.

PHAST Ver. 6.7 models all stages of a release from outflow through a hole or from a pipe end,

through atmospheric dispersion to thermal radiation from fires and explosion overpressures.

The consequence outputs from PHAST Ver. 6.7 software are:

The dimensions of the jet fire in terms of jet length and thermal radiation effect distance;

The downwind distance to 100% Lower Flammable Limit (LFL);

Damage Contours in terms of Jet, Flash fire and Explosion; and

Explosion Overpressure

Reference:

1. PHAST Ver. 6.7 Technical Notes

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HAZARD IDENTIFICATION

Assumption A3 Representative Hole Size

Based on the OGP guidelines, the following hole sizes shall be considered for the RA study purpose.

Leak Type. Hazard Material Hole Size (mm)

Large Leak Flammable Release 50

Pin hole Leak Toxic Release 5

Reference:

1. The leak sizes considered for RA and consequence analysis are aligned with the leak sizes available in OGP Risk Assessment Data Directory - Report No. 434 (March 2010).

2. Risk Analysis Report (PDRP4280-8150-RP-0001 Rev A3)

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HAZARD IDENTIFICATION

Assumption No: A4 Scenario Identification

The definition of the isolatable sections boundaries is based on study of the PFDs and P&IDs.

The limits of the isolatable sections are defined and bounded by the location of the following:

Emergency Shutdown Valves (ESDVs);

Emergency Depressurization Valves (EDPVs);

Normally Closed valve with positive isolation;

Pressure Safety Valve (PSVs).

This identification step is based on a worst possible case or based on the maximum amount of

material within a process loop, or a worst possible (credible) case from a hazards review. The

purpose of short listing failure cases is to focus attention on those cases, which shall give a

realistic idea of worst case scenario consequences for similar incidents.

The sections containing non-hazardous material (such as water or air) are not considered in the

study.

It is essential to identify the scenario based on isolatable section approach. A worst possible

(credible) scenario will be selected based on vulnerable equipment and associated piping

system.

Reference:

1. CPR-18E-Guidelines for RA(Purple Book)

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METEOROLOGICAL DATA

Assumption No: A5 Meteorological Data

Weather Data: Following weather conditions will be considered for RA Study

Sr. No. Parameter Value

1

Ambient Temperature 22.4°C

2 Relative Humidity 80%

3 Surface Roughness Length 0.3 m

Wind Speed & Stability Class: Following wind speed & stability conditions will be considered for RA Study

Sr. No. Wind Speed (m/s) Pasquill Stability Category

4 3 D

5 5 D

Reference:

1. Sr. No. 1, 2, 4 & 5 - Risk Analysis Report (PDRP4280-8150-RP-0001 Rev A3)

2. Sr. No. 3 - Phast 6.7 Technical Notes

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CONSEQUENCE MODELLING

Assumption No: A6 Isolation Time & Release Direction

Release Duration:

The closing (isolation) time of the systems is based on the following considerations:

An automatic blocking system is a system where the detection of the leakage and closure of the blocking valves is fully automatic. There is no action of an operator required. The closing time of the blocking valve is 2 min.

A remote-controlled blocking system is a system where the detection of the leakage is fully automatic. The detection results in a signal in the control room. The operator validates the signal and closes the blocking valves using a switch in the control room. The closing time of the blocking valve is 10 min.

A hand-operated blocking system is a system where the detection of the leakage is fully automatic. The detection results in a signal in the control room. The operator validates the signal, goes to the location of the blocking valves and closes the valves by hand. The closing time of the blocking valve is 30 min.

This is the conservative approach considered for assessment rather than the actuals to study worst case effects (Purple book).

1 hour release duration will be considered for identified worst case and the same shall be used as an input for preparation of guideline for Disaster Management plan.

Release Direction:

As pipeline is aboveground, leak release orientation is considered in horizontal plane for estimating risk to personnel as conservative approach.

Release Height

The height of the outflow in relation to the surrounding area is determined by the location of the vessel or the pipeline. The height is equal to the location of the pipeline or the bottom of the vessel, given a minimum height of one meter. A height of 0 meters is only assumed for underground pipelines and vessels.

Release Inventory

Release inventory will be estimated based on the following equation: Release inventory = Initial release rate x Isolation time + Inventory of associated main equipment

(A) + Inventory of associated piping.

Reference:

1. CPR 18E, Guideline for quantitative risk assessment, Purple book

A2

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0013, Rev-A2



Assumption No: A7 Representative Process Parameters

The material characterization such as Pressure, Temperature and Composition etc. for

each scenario shall be taken from Piping & Instrumentation Diagram, Process Flow

Diagram & Heat and mass balance.

To have more conservative approach, the condition such as maximum pressure and

minimum temperature stream in the section shall be taken into consideration.

Reference:

1. CPR 18E, Guideline for quantitative risk assessment, Purple book.

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0013, Rev-A2


CONSEQUENCE MODELLING Assumption No: A8 Physical Effect Modelling Depending on the type of release, the expected outcomes of consequence analysis are:

For gas & two-phase release under pressure:

Jet Fire

This outcome occurs following the immediate ignition of a flammable material, usually from a

pressurized source.

Flash Fire

Flash fires arise from delayed ignition of a well-mixed flammable gas/ vapor cloud in the

absence of significant confinement or obstruction. There are minimal overpressure effects and

primarily local impacts.

Vapor Cloud Explosion (VCE)

When a flammable vapor or gas mixes with air and its concentration lies between the lower

flammable limit (LFL) and upper flammable limit (UFL). An ignition source will ignite the mixture.

If this event takes place in a confined space then the enclosure usually suffers a significant

internal overpressure for a short duration.

Toxic Gas Dispersion

The results of toxic dispersion shall be analyzed and the distances for dispersion of toxic

components will be reported.

Boiling Liquid Expanding Vapor Explosion (BLEVE)

It results from the sudden failure of vessel containing liquid at a temperature well above its

normal (atmospheric) boiling point.

For liquid release:

Pool Fire

Pool fire will occur from an ignited liquid pool resulting from a liquid release.

Reference:

1. CPR 18E, Guideline for quantitative risk assessment, Purple book. 2. PHAST Risk v6.7 / 7.1 Release Notes

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0013, Rev-A2



Assumption No: A9 Impact Criteria

Thermal Radiation Following thermal radiation levels, are proposed to be set as thresholds

Radiation Level (kW/m2) Impact

4.0 Sufficient to cause pain to personnel if unable to reach cover within 20 seconds, however, blistering of skin (1st degree burn) is likely

12.5 Minimum energy required for piloted ignition of wood, melting of plastic etc.

37.5 Sufficient to cause damage to process equipment

Explosion Radiation Following explosion overpressure levels, are considered to be set as thresholds

Overpressure Level (barg) Impact

0.3 Wooden utility poles snapped; tall hydraulic pressure in building, slightly damaged

0.1 Steel frame of clad building slightly distorted

0.03 Limited minor structural damage

For the study TNT model of PHAST 6.7 will be used.

Toxic Release For toxic release, IDLH limit will be used to determine the extent of the toxic hazard created as

the result of loss of containment of a toxic substance. The IDLH values were taken from NIOSH

Chemical Listing and Documentation of Revised IDLH Values 2009.

Sr. No. Substance IDLH (ppm) Institute

1 Ethylene Oxide (EO) 800 NIOSH

Reference: 1. Tender Document - RHQCC15138 Pg. 90 / 194 & 91 / 194 2. Risk Analysis Report (Doc. No.: PDRP4280-8150-RP-0001 Rev A4) 3. OGP Risk Assessment Data Directory, Vulnerability of Humans, Report no. 434-14.1,

434-15 March 2010 4. Methods of the determination of possible damage, “Green Book”, CPR 16E, TNO 1992

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DOC NO. : IEGP-6351-8110-RA-

000-0001, Rev-I3

ISSUED : 21-Aug-2017 IEGP PAGE B1 OF B5

ATTACHMENT - B

CONSEQUENCE ANALYSIS RESULTS

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DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Unit Cases Failure Case

Operating Conditions

State Release

Rate kg/s

Weather Flash Fire (m)

Jet Fire (m) / Fire Ball Pool Fire (m) Blast Over Pressure (m)

IDLH Conc.

Distance (m)

NOTE Temp (OC)

Press. (kg/cm2g)

4 kW/m2

12.5 kW/m2

37.5 kW/m2

4 kW/m

2

12.5 kW/m2

37.5 kW/m2

0.03 bar

0.1 bar 0.3 bar

ER

ER1 DGA/Water wash tower overhead line instrument tapping failure 40 13.1 V 4.7

3D 18 36 29 24 - - - 30 19 14

5D 17 36 30 25 - - - 30 19 14

ER2 DGA Reflux drum overhead line pin hole leak 98 1.5 V 0.01

3D - - - - - - - - - - 16 Toxic release - H2S

5D - - - - - - - - - - 10

ER3 Caustic / Water Wash Tower overhead line instrument tapping failure 54.8 11.30 V 3.99 3D 16 33 27 22 - - - 29 18 14

5D 15 33 28 23 - - - 29 18 14

ER4 FCC Off gas Oxygen Converter outlet line flange gasket leak 266 10.40 V 2.79

3D 12 28 22 18 - - - 27 17 13

5D 11 28 23 19 - - - 26 17 13

ER5 Process off gas line from C-101 to Dryer feed KOD flange leakage 55 9.90 V 3.54

3D 15 31 25 20 - - - 29 18 14

5D 14 31 26 21 - - - 28 18 14

ER6 Mercury Absorber Effluent filter flange gasket leak 16 9.00 V 3.48

3D 15 31 25 20 - - - 29 18 14

5D 14 31 26 21 - - - 28 18 14

ER7 Regeneration gas line instrument tapping failure 300 6.90 V 1.6

3D 7 21 17 8 - - - - - -

5D 7 21 17 NR - - - - - -

ER8 Demethanizer Bottoms Pumps seal failure -43 8.4 L .15 3D 3 8 7 5 - - - - - -

5D 3 8 6 5 - - - - - -

ER9 Demethanizer Intercooler Circulation pump seal failure -84.7 9.50 L 0.23

3D 4 8 NR NR - - - - - -

5D 4 8 NR NR - - - - - -

ER10 Deethylenizer overhead line instrument tapping failure -33.5 16.90 V 7.67 3D 52 57 46 39 - - - 107 75 62 5D 52 54 42 35 - - - 105 74 62

ER11 Ethylene Product pump seal failure -31.7 45.50 L 3.13 3D 26 37 30 25 - - - 51 33 26

5D 24 35 28 23 - - - 49 32 26

ER12 Deethylenizer bottom line flange gasket leak 51.4 17.60 L 9.11

3D 30 53 42 33 - - - 70 47 38

5D 29 29 14 12 - - - 55 35 27

ER13 Catastrophic rupture of Deethylenizer Reflux Drum -35 16.20 L -

3D 64 350 186 67 - - - 493 227 131

5D 100 350 186 67 - - - 497 230 142

ER14 Catastrophic Rupture of Light Binary Refrigerant Accumulator -1 25.10 L -

3D 19 178 94 34 - - - 182 83 47

5D 24 178 94 34 - - - 207 100 60

ER15 Binary Refrigerant Compressor discharge instrument tapping failure 84 27.40 V 11.8

3D 36 58 46 36 - - - 74 49 39

5D 35 59 47 38 - - - 73 49 39

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DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3




State Release

Rate kg/s


Jet Fire (m) Pool Fire (m) Blast Over Pressure (m) IDLH

Conc. Distance

(m)

NOTE Temp (OC)

Press. (kg/cm2g) 4 kW/m2

12.5 kW/m2

37.5 kW/m2

4 kW/m2

12.5 kW/m2

37.5 kW/m2

0.03 bar

0.1 bar

0.3 bar

EG

EG1 Ethylene Filter flange gasket leak 35 25.00 V 10.45 3D 41 55 44 35 - - - 88 61 50 - 5D 40 55 45 36 - - - 87 60 50 -

EG2 Reactor Feed line instrument tapping failure 57 21.37 V 8.30 3D 7 38 30 NR - - - - - -

5D 7 39 32 NR - - - - - -

EG3 Reactor outlet line flange gasket leak 90 19.33 V 7.15 3D 6 35 28 10 - - - - - - - 5D 6 36 29 12 - - - - - - -

EG4 Recycle Compressor instrument tapping failure 41 21.52 V 8.59 3D 6.8 37.5 30 13 - - - - - - -

5D 6.5 38.5 31 14 - - - - - - -

EG5 Ballast line flange gasket leak 45 25 V 7.46 3D 27 49 39 31 - - - 54 34 27 - 5D 26 49 39 32 - - - 53 34 27 -

EG6 Acid Scrubber outlet flange gasket leakage 51 0.28 L 0.36

3D 4 11 NR NR - - - - - - 96 Toxic release - EO

5D 4 12 NR NR - - - - - - 67

EG7 Pin hole leak at inlet of Stripping Column condenser (Toxic Release) 97 0.48 L 0.38


5D 2 10 NR NR - - - - - - 59

EG8 Flange gasket leak in Reclaim Compressor discharge 127 23.00 V 8.3 3D 12 41 33 24 - - - 26 17 13 -

5D 11 42 34 26 - - - 26 17 13 -

EG9 Glycol Feed Stripper Overhead line instrument tapping failure 51 0.28 L 0.36


5D 3..5 12 10 NR - - - - - - 67

EG10 Concentrated Glycol Pump seal failure 91 0.29 L 0.87 3D 4 11 9 NR 44 21 NR - - - - 5D 4 10 8 NR 46 22 NR - - - -

EG11 Drying Column Bottoms Pump seal failure 162 0.17 L 0.35 3D 2 4 NR NR 34 20 11 - - - - 5D 2 4 NR NR 35 23 11 - - - -

EG12 50 mm hole on MEG Column overhead line

139

0.18 L 0.32 3D 3 9 NR NR - - - - - - -

5D 2 11 NR NR - - - - - - -

EG13 MEG Column Bottoms Pump seal failure 164 0.50 L 0.53 3D 3 8 7 NR 40 21 NR - - - - 5D 3 7 5 19 41 23 NR - - - -

EG14 MEG Product Transfer Pump seal failure 48 5.50 L 1.8 3D 7 2 NR NR 58 28 NR - - - 5D 7 2 NR NR 61 29 NR - - -

EG15 MEG Splitter Bottoms Pump discharge instrument tapping failure 175 7.45 L 51.1 3D 22 43 35 29 97 54 NR 48 32 26 5D 22 39 31 25 103 55 NR 48 32 26

EG16 DEG Column Bottoms Pump seal failure 178 6.60 L 1.92 3D 10 7 6 6 64 32 NR - - - -

5D 11 8 6 5 68 34 NR 18 14 12 -

EG17 DEG Product Transfer Pump discharge instrument tapping failure 55 5 L 16.21

3D 13.5 3.13 NR NR 50.29 31.49 NR NR NR NR -

5D 13.5 2.96 NR NR 51.38 33.14 NR NR NR NR -

EG18 TEG Product Transfer pump discharge instrument tapping failure 164 5 L 39.6

3D 15.4 26.6 21 17.36 42.5 32.7 22.6 17.8 13.3 11.6 - 5D 15.5 24.4 19.0 15.58 43.3 34.1 22.7 18.4 13.6 11.8 -

EG19 Moderator Feed Drum line rupture 40 23.5 L 64.7 3D 11.7 79 64 52 173 87 38 15 12 11 -

5D 11.7 75 60 50 186 101 41 15 12 11 -

agparanjpe

Snapshot

agparanjpe

Snapshot

agparanjpe

Snapshot

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Rev-I3




State Release

Rate kg/s


Jet Fire (m)/Fire Ball Pool Fire (m) Blast Over Pressure (m)

IDLH Conc.

Distance (m)

NOTE Temp (OC)

Press. (kg/cm2g)

4 kW/m2

12.5 kW/m2

37.5 kW/m2

4 kW/m2

12.5 kW/m2

37.5 kW/m2

0.03 bar

0.1 bar

0.3 bar

O&U

OU1 Flange gasket failure at the outlet of ethylene sphere -31.7 18 L 8.9

3D 41 55 44 38 - - - 88 61 50 -

5D 40 52 41 34 - - - 87 60 50 -

OU2 Flange gasket leak at BOG Package -31.3 18 V 8.89 3D 41 55 44 38 - - - 88 61 50 -

5D 40 52 41 34 - - - 87 60 50 -

OU3 Ethylene Product Transfer Pump seal failure -31.7 29 L 2.55

3D 23 34 27 23 - - - 48 32 26 - 5D 20 32 25 21 - - - 46 31 25 -

OU4 Ethylene Vaporizer outlet line instrument tapping failure 40 27 L 11.38

3D 43 58 45 36 - - - 91 62 51 - 5D 43 58 46 37 - - - 89 61 50 -

OU5 Catastrophic rupture of Ethylene Sphere -31.7 18 L - 3D 433 1840 1007 395 - - - 2657 1133 566 - 5D 680 1840 1007 395 - - - 2657 1133 566 -

OU6 MEG Product Transfer pump seal leak 48 Atm L 0.2 3D 2 NR NR NR 30 19 9 - - - - 5D 2 NR NR NR 31 21 9 - - - -

OU7 Ship Loading pump discharge flange gasket leak 48 3.25 L 34.5

3D 10 7 6 NR 183 96 NR 12 11 10 - 5D 10 6 6 NR 193 97 NR 13 11 10 -

OU8 MEG Truck loading arm leak 48 1.5 L 23.4 3D 7 3.6 NR NR 115 56 NR - - - - 5D 7 3.4 NR NR 121 57 NR - - - -

OU9 MEG Tank on Fire 48 Atm L - 3D 27 - - - 40 18 NR 44 30 25 - 5D 28 - - - 42 19 NR 48 32 26 -

OU10 DEG Product Transfer pump seal leak 48 Atm L 0.1 3D 1 NR NR NR 23 16 7 - - - - 5D 1 NR NR NR 24 17 7 - - - -

OU11 DEG Truck loading arm leak 48 1.5 L 28.3 3D 9 NR NR NR 97 47 NR - - - - 5D 9 NR NR NR 103 49 NR - - - -

OU12 DEG Tank on Fire 48 Atm L - 3D 31 - - - 330 187 NR 38 33 32 - 5D 29 - - - 350 188 NR 29 24 22 -

OU13 TEG Product Transfer pump seal leak 48 Atm L 0.1 3D 1 NR NR NR 23 16 7 - - - - 5D 1 NR NR NR 24 17 7 - - - -

OU14 TEG Truck loading arm leak 48 1.5 L 28.4 3D 9 NR NR NR 98 47 NR - - - - 5D 9 NR NR NR 103 48 NR - - - -

OU15 TEG Tank on Fire 48 Atm L - 3D 16 - - - 158 78 NR 12 11 10 - 5D 15 - - - 165 76 NR 12 11 10 -

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Cases Failure Case


State Release

Rate kg/s


Jet Fire (m) Pool Fire (m) Blast Over Pressure (m)

IDLH Conc.

Distance (m)

NOTE Temp (OC)

Press. (kg/cm2g)

4 kW/m2

12.5 kW/m2

37.5 kW/m2

4 kW/m2

12.5 kW/m2

37.5 kW/m2

0.03 bar

0.1 bar

0.3 bar

CC1

C3+ Product header from ERU to PRU

rupture

40 16.5 L 49.1

3D 14 28 20 NR - - - 30 18 14 -

5D 13 26 18 11 - - - 28 18 14 -

CC2

50 mm hole on Fuel Gas header from

ERU to Refinery fuel gas system

40 12.1 V 4.38

3D 16 34 24 NR - - - 30 18 14 -

5D 15 34 25 NR - - - 29 18 14 -

CC3 50 mm hole on Refinery Off gas header

from FCC to ERU 40 4 V 1.46 3D 8 16 NR NR - - - - - - -

5D 8 16 NR NR - - - - - - -

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DOC NO. : IEGP-6351-8110-RA-

000-0001, Rev-I3

ISSUED : 21-Aug-2017 IEGP PAGE C1 OF C148

ATTACHMENT - C

CONSEQUENCE ANALYSIS HAZARD CONTOURS

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DOC NO. : IEGP-6351-8110-RA-

000-0001, Rev-I3


Figures shown below are the worst case distances out of two weather condition i.e. farthest hazard

distances (for flash fire, jet fire, pool fire, overpressure, toxic dispersion) are reported out of

weather condition 3D and 5D.

The distances for hazard outcomes are shown in Annexure –B.

Ethylene Recovery Unit (ER): Figure C1.1 through C1.40

Ethylene Glycol Unit (EG): Figure C2.1 through C2.57

Offsite & Utilities Facility: Figure C3.1 through C3.41

Client Cases: Figure C4.1 through C4.8

agparanjpe

Snapshot

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Figure C1.1: Case - ER1- DGA/Water Wash tower overhead line instrument tapping failure - Flash Fire contour (Weather Condition 3D)

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Figure C1.2: Case - ER1- DGA/Water Wash tower overhead line instrument tapping failure - Jet Fire contour (Weather Condition 5D)

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Figure C1.3: Case - ER1- DGA/Water Wash tower overhead line instrument tapping failure - Overpressure contour (Weather Condition 3D)

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Figure C1.4: Case – ER2 – DGA Reflux drum overhead line pin hole leak – Toxic substance (H2S) release contour (Weather Condition 3D)

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Figure C1.5: Case – ER3 –Caustic/Water Wash tower overhead line instrument tapping failure - Flash Fire contour (Weather Condition 3D)

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Figure C1.6: Case – ER3 –Caustic/Water Wash tower overhead line instrument tapping failure – Jet Fire contour (Weather Condition 5D)

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Figure C1.7: Case – ER3 –Caustic/Water Wash tower overhead line instrument tapping failure - Overpressure contour (Weather Condition 3D)

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Figure C1.8: Case – ER4 – FCC Off-gas Oxygen Converter outlet line flange gasket leak - Flash Fire contour (Weather Condition 3D)

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Figure C1.9: Case – ER4 – FCC Off-gas Oxygen Converter outlet line flange gasket leak – Jet Fire contour (Weather Condition 5D)

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Figure C1.10: Case – ER4 – FCC Off-gas Oxygen Converter outlet line flange gasket leak – Overpressure contour (Weather Condition 3D)

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Figure C1.11: Case – ER5 – Process off gas line from C-101 to Dryer Feed KOD flange gasket leakage - Flash Fire contour (Weather Condition 3D)

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Figure C1.12: Case – ER5 – Process off gas line from C-101 to Dryer Feed KOD flange gasket leakage – Jet Fire contour (Weather Condition 5D)

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Figure C1.13: Case – ER5 – Process off gas line from C-101 to Dryer Feed KOD flange gasket leakage – Overpressure contour (Weather Condition 3D)

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Figure C1.14: Case – ER6 – Mercury Absorber Effluent Filter flange gasket leakage - Flash Fire contour (Weather Condition 3D)

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Figure C1.15: Case – ER6 – Mercury Absorber Effluent Filter flange gasket leakage – Jet Fire contour (Weather Condition 5D)

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Figure C1.16: Case – ER6 – Mercury Absorber Effluent Filter flange gasket leakage - Overpressure contour (Weather Condition 3D)

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Figure C1.17: Case – ER7 – Regeneration gas line instrument tapping failure - Flash Fire contour (Weather Condition 3D)

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Figure C1.18: Case – ER7 – Regeneration gas line instrument tapping failure - Jet Fire contour (Weather Condition 3D)

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Figure C1.19: Case – ER8 –Demethanizer Bottoms pump seal failure – Flash Fire contour (Weather Condition 3D)

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Figure C1.20: Case – ER8 –Demethanizer Bottoms pump seal failure – Jet Fire contour (Weather Condition 3D)

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Figure C1.21: Case – ER9 –Demethanizer Intercooler Circulation pump seal failure – Flash Fire contour (Weather Condition 3D)

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Figure C1.22: Case – ER9 –Demethanizer Intercooler Circulation pump seal failure –Jet Fire contour (Weather Condition 3D)

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Figure C1.23: Case – ER10 –Deethylenizer Overhead line instrument tapping failure – Flash Fire contour (Weather Condition 5D)

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Figure C1.24: Case – ER10 –Deethylenizer Overhead line instrument tapping failure – Jet Fire contour (Weather Condition 3D)

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Figure C1.25: Case – ER10 –Deethylenizer Overhead line instrument tapping failure – Overpressure contour (Weather Condition 3D)

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Figure C1.26: Case – ER11 – Ethylene Product Pump seal failure – Flash Fire contour (Weather Condition 3D)

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Figure C1.27: Case – ER11 – Ethylene Product Pump seal failure – Jet Fire contour (Weather Condition 3D)

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Figure C1.28: Case – ER11 – Ethylene Product Pump seal failure – Overpressure contour (Weather Condition 3D)

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Figure C1.29: Case – ER12 – Deethylenizer Bottom line flange gasket leak – Flash Fire contour (Weather Condition 3D)

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Figure C1.30: Case – ER12 – Deethylenizer Bottom line flange gasket leak – Flash Fire contour (Weather Condition 3D)

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Figure C1.31: Case – ER12 – Deethylenizer Bottom line flange gasket leak –Overpressure contour (Weather Condition 3D)

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Figure C1.32: Case – ER13 – Catastrophic rupture of Deethylenizer Reflux Drum – Flash Fire contour (Weather Condition 5D)

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Figure C1.33: Case – ER13 – Catastrophic rupture of Deethylenizer Reflux Drum – Fire Ball contour (Weather Condition 5D)

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Figure C1.34: Case – ER13 – Catastrophic rupture of Deethylenizer Reflux Drum – Overpressure contour (Weather Condition 5D)

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Figure C1.35: Case – ER14 – Catastrophic rupture of Light Binary Refrigerant Accumulator – Flash Fire contour (Weather Condition 5D)

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Figure C1.36: Case – ER14 – Catastrophic rupture of Light Binary Refrigerant Accumulator –Fire Ball contour (Weather Condition 5D)

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Figure C1.37: Case – ER14 – Catastrophic rupture of Light Binary Refrigerant Accumulator – Overpressure contour (Weather Condition 5D)

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Figure C1.38: Case – ER15 – Binary Refrigerant Compressor discharge instrument tapping failure – Flash Fire contour (Weather Condition 3D)

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Figure C1.39: Case – ER15 – Binary Refrigerant Compressor discharge instrument tapping failure – Jet Fire contour (Weather Condition 5D)

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DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C1.40: Case – ER15 – Binary Refrigerant Compressor discharge instrument tapping failure – Overpressure contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.1: Case - EG1- Ethylene Filter flange gasket leak - Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.2: Case - EG1- Ethylene Filter flange gasket leak - Jet Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.3: Case - EG1- Ethylene Filter flange gasket leak - Overpressure contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.4: Case – EG2- Reactor Feed line instrument tapping failure - Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.5: Case – EG2- Reactor Feed line instrument tapping failure - Jet Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.6: Case – EG3 - Reactor outlet line flange gasket leak - Flash Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.7: Case – EG3 - Reactor outlet line flange gasket leak - Jet Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.8: Case – EG4 – Recycle Compressor Instrument tapping failure - Flash Fire contour (Weather Condition 5D)

agparanjpe

Snapshot

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.9: Case – EG4 – Recycle Compressor Instrument tapping failure - Jet Fire contour (Weather Condition 5D)

agparanjpe

Snapshot

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.10: Case – EG5 – Ballast line flange gasket leak - Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.11: Case – EG5 – Ballast line flange gasket leak - Jet Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.12: Case – EG5 – Ballast line flange gasket leak - Overpressure contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.13: Case – EG5 – Ballast line flange gasket leak - Fireball contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.14: Case – EG6 – Acid Scrubber outlet flange gasket leak - Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.15: Case – EG6 – Acid Scrubber outlet flange gasket leak - Jet Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.16: Case – EG6 – Acid Scrubber outlet flange gasket leak - Toxic Gas (IDLG-EO) contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.17: Case – EG7 – Pin hole leak at inlet of Stripping Column Condenser - Flash Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.18: Case – EG7 – Pin hole leak at inlet of Stripping Column Condenser - Jet Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.19: Case – EG7 – Pin hole leak at inlet of Stripping Column Condenser – Toxic Gas (O-IDLH) contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.20: Case – EG8 – Flange gasket leak in Reclaim Compressor discharge- Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.21: Case – EG8 – Flange gasket leak in Reclaim Compressor discharge - Jet Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.22: Case – EG8 – Flange gasket leak in Reclaim Compressor discharge – Overpressure contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.23: Case – EG9 –Glycol Feed Stripper Overhead line instrument tapping failure – Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.24: Case – EG9 –Glycol Feed Stripper Overhead line instrument tapping failure – Jet Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.25: Case - EG9 - Glycol Feed Stripper Overhead line instrument tapping failure - Toxic Gas (EO-IDLH) contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.26: Case - EG10 – Concentrated Glycol Pump seal failure – Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.27: Case - EG10 – Concentrated Glycol Pump seal failure – Jet Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.28: Case - EG10 – Concentrated Glycol Pump seal failure – Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.29: Case - EG11 – Drying Column Bottoms Pump seal failure – Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.30: Case - EG11 – Drying Column Bottoms Pump seal failure – Jet Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.31: Case - EG11 – Drying Column Bottoms Pump seal failure – Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.32: Case - EG12 – 50 mm hole on MEG Column overhead line – Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.33: Case - EG12 – 50 mm hole on MEG Column overhead line – Jet Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.34: Case - EG13 – MEG Column Bottoms Pump seal failure - Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.35: Case - EG13 – MEG Column Bottoms Pump seal failure - Jet Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.36: Case - EG13 – MEG Column Bottoms Pump seal failure - Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.37: Case - EG14 - MEG Product Transfer Pump seal failure - Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.38: Case - EG14 - MEG Product Transfer Pump seal failure – Jet Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.39: Case - EG14 - MEG Product Transfer Pump seal failure – Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.40: Case - EG15 - MEG Splitter Bottom Pump seal failure – Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.41: Case - EG15 - MEG Splitter Bottom Pump seal failure – Jet Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.24: Case - EG15 - MEG Splitter Bottom Pump seal failure - Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.43: Case - EG15 - MEG Splitter Bottom Pump seal failure - Overpressure contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.44: Case - EG16 - DEG Column Bottom Pump seal failure – Flash Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.45: Case - EG16 - DEG Column Bottom Pump seal failure – Jet Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.46: Case - EG16 - DEG Column Bottom Pump seal failure –Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.47: Case - EG16 - DEG Column Bottom Pump seal failure – Overpressure contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.48: Case - EG17 - DEG Product Transfer Pump discharge instrument tapping failure – Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.49: Case - EG17 - DEG Product Transfer Pump discharge instrument tapping failure – Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.50: Case - EG18 - TEG Product Transfer Pump discharge instrument tapping failure – Flash Fire contour (Weather Condition 3D)

agparanjpe

Snapshot

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.51: Case - EG18 - TEG Product Transfer Pump discharge instrument tapping failure – Jet Fire contour (Weather Condition 3D)

agparanjpe

Snapshot

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.52: Case - EG18 - TEG Product Transfer Pump discharge instrument tapping failure – Pool Fire contour (Weather Condition 5D)

agparanjpe

Snapshot

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.53: Case - EG18 - TEG Product Transfer Pump discharge instrument tapping failure –Overpressure contour (Weather Condition 5D)

agparanjpe

Snapshot

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.54: Case - EG19 – Moderator Feed Drum line rupture – Flash Fire contour (Weather Condition 3D)

agparanjpe

Snapshot

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.55: Case - EG19 – Moderator Feed Drum line rupture – Jet Fire contour (Weather Condition 3D)

agparanjpe

Snapshot

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.56: Case - EG19 – Moderator Feed Drum line rupture – Pool Fire contour (Weather Condition 5D)

agparanjpe

Snapshot

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C2.57: Case - EG19 – Moderator Feed Drum line rupture – Overpressure contour (Weather Condition 5D)

agparanjpe

Snapshot

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.1: Case - OU1 - Flange gasket failure at the outlet of ethylene sphere - Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.2: Case - OU1 - Flange gasket failure at the outlet of ethylene sphere - Jet Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.3: Case - OU1 - Flange gasket failure at the outlet of ethylene sphere - Overpressure contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.4: Case – OU2 - Flange gasket leak at BOG Package – Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.5: Case – OU2 - Flange gasket leak at BOG Package –Jet Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.6: Case – OU2 - Flange gasket leak at BOG Package – Overpressure contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.7: Case – OU3 – Ethylene Product Transfer Pump Seal failure – Flash Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.8: Case – OU3 - Ethylene Product Transfer Pump Seal failure – Jet Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.9: Case – OU3 – Ethylene Product Transfer Pump Seal failure – Overpressure contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.10: Case – OU4 – Ethylene Vaporizer outlet line instrument tapping failure – Flash Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.11: Case – OU4 – Ethylene Vaporizer outlet line instrument tapping failure – Jet Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.12: Case – OU4 – Ethylene Vaporizer outlet line instrument tapping failure – Overpressure contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.13: Case – OU5 – Catastrophic rupture of Ethylene Storage Sphere – Flash Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.14: Case – OU5 – Catastrophic rupture of Ethylene Storage Sphere – Fireball contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.15: Case – OU5 – Catastrophic rupture of Ethylene Storage Sphere – Overpressure contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.16: Case – OU6 – MEG Product Transfer Pump Seal leak – Flash Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.17: Case – OU6 – MEG Product Transfer Pump Seal leak – Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.18: Case – OU7 – Ship loading pump discharge flange gasket leak – Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.19: Case – OU7 – Ship loading pump discharge flange gasket leak – Jet Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.20: Case – OU7 – Ship loading pump discharge flange gasket leak – Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.21: Case – OU7 – Ship loading pump discharge flange gasket leak – Overpressure contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.22: Case – OU8 – Truck loading arm leak – Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.23: Case – OU8 – Truck loading arm leak – Jet Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.24: Case – OU8 – Truck loading arm leak – Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.25: Case – OU9 – MEG Tank on Fire – Flash Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.26: Case – OU9 – MEG Tank on Fire – Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.27: Case – OU9 – MEG Tank on Fire – Overpressure contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.28: Case – OU10 – DEG Product Transfer pump seal leak – Flash Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.29: Case – OU10 – DEG Product Transfer pump seal leak – Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.30: Case – OU11 – DEG Loading arm leak – Flash Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.31: Case – OU11 – DEG Loading arm leak – Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.32: Case – OU12 – DEG Tank on fire – Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.33: Case – OU12 – DEG Tank on fire – Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.34: Case – OU12 – DEG Tank on fire – Overpressure contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.35: Case – OU13 – TEG Product Transfer pump seal leak – Flash Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.36: Case – OU13 – TEG Product Transfer pump seal leak – Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.37: Case – OU14 – TEG Loading arm leak – Flash Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.38: Case – OU14 – TEG Loading arm leak – Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.39: Case – OU15 – TEG Tank on fire – Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.40: Case – OU15 – TEG Tank on fire – Pool Fire contour (Weather Condition 5D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C3.41: Case – OU15 – TEG Tank on fire – Overpressure contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C4.1: Case – CC1 – C3+ Product header from ERU to PRU rupture - Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C4.2: Case – CC1 – C3+ Product header from ERU to PRU rupture - Jet Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C4.3: Case – CC1 – C3+ Product header from ERU to PRU rupture - Overpressure contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C4.4: Case – CC2 - 50 mm hole on Fuel Gas header from ERU to Refinery fuel gas system - Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C4.5: Case – CC2 - 50 mm hole on Fuel Gas header from ERU to Refinery fuel gas system - Jet Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C4.6: Case – CC2 - 50 mm hole on Fuel Gas header from ERU to Refinery fuel gas system - Overpressure contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C4.7: Case – CC3 - 50 mm hole on Refinery Off gas header from FCC to ERU - Flash Fire contour (Weather Condition 3D)

<Security Level 2>


RA STUDY REPORT

DOC NO. : IEGP-6351-8110-RA-000-0001,

Rev-I3


Figure C4.8: Case – CC3 - 50 mm hole on Refinery Off gas header from FCC to ERU - Jet Fire contour (Weather Condition 3D)

Report: U1804-Rev01

Revision: A

Date: 16/02/2018

Use of this document is subject to the confidentiality provisions and intellectual property rights in the terms and conditions applicable to the contract under which it was produced.

Rapid Risk Assessment Report

Rapid Risk Assessment Study for BS VI – IOCL Paradip

EPC Works for Paradip Refinery Compliant


Report Ref: U1804-Rev01 Page 2 of 34 © Copyright Bell Energy 2018

Version: A 16.02.2018

Project / Facility: Rapid Risk Assessment Study for BS VI – IOCL Paradip

Study: Rapid Risk Assessment Report

Doc. No: U1804-Rev01

Revision: A

Issue Date: 16.02.2018

Prepared for: IOCL Paradeep

Prepared by: Bell Engineering Software Technologist LTD, Abu Dhabi.

Rev Date Issue Prepared by Reviewed by Approved by

A 16.02.2018 Issued for Review

Kenny Loh C G Kulkarni




Version: A 16.02.2018

Table of Contents Abbreviations ............................................................................................................................................. 6

1 Introduction........................................................................................................................................... 8

1.1 Background .................................................................................................................................. 8

1.2 Purpose of RRA ........................................................................................................................... 8

1.3 Project Description ....................................................................................................................... 8

2 Project Description ............................................................................................................................. 11

2.1 Process Description of DHDT Unit ............................................................................................. 11

2.2 Process Description of HGU Unit ............................................................................................... 12

2.3 Process Description of IGHDS Unit ........................................................................................... 12

2.3.1 Selective Hydrogenation Section (SHU): ................................................................................... 12

2.3.2 LCN and MCN Splitters Section: ................................................................................................ 13

2.3.3 Selective HCN HDS Section – 1 stage HDS scheme: ............................................................... 13

2.3.4 Selective MCN HDS Section – 1 stage HDS scheme: .............................................................. 13

2.3.5 HCN and MCN Stabilizer Sections: ........................................................................................... 13

2.4 Process Description of ISOM Unit ............................................................................................. 14

2.5 Process Description of KHDS Unit ............................................................................................. 15

3 Types of Risk ..................................................................................................................................... 16

3.1 Flammable Gas Dispersion ........................................................................................................ 16

3.2 Flash Fire ................................................................................................................................... 16

3.3 Vapor Cloud Explosion ............................................................................................................... 16

3.4 Jet Fire ....................................................................................................................................... 16

3.5 Pool Fire. .................................................................................................................................... 16

3.5.1 Surface Fire ........................................................................................................................ 16

3.5.2 Bund Fire. ........................................................................................................................... 16

4 Methodology Adapted ........................................................................................................................ 17

5 Considerations for Disaster Management Plan. ................................................................................ 18

6 Hazards Identification ......................................................................................................................... 19

7 Risk Acceptance Criteria. ................................................................................................................... 20

8 Assumptions and Study Basis ........................................................................................................... 21




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8.1 Following assumptions and basis of study were made : ............................................................ 21

8.2 Meteorological data. ................................................................................................................... 22

Wind 22

9 Conclusions and Recommendations ................................................................................................. 24

Annexure ................................................................................................................................................... 25

ISO Risk Contour od DHDT unit. ........................................................................................................... 25

ISO Risk Contour of IGDHS unit. ........................................................................................................... 25

ISO Risk Contour of KHDS .................................................................................................................... 26

ISO Risk Contour of HGU ...................................................................................................................... 26

ISO Risk Contour of ISOM ..................................................................................................................... 27

Combined ISO Risk Contour .................................................................................................................. 27

List of Figures Figure 1-1 – Overall Plot Plan .................................................................................................................... 10

Figure 1-2 – Overall Plot Plan .................................................................................................................... 10

Figure 7-1 – Risk Acceptance Criteria ....................................................................................................... 20

Figure 9-1 - ISO Risk Contour of DHDT unit.............................................................................................. 25

Figure 9-2 - ISO Risk Contour of IGDHS unit. ........................................................................................... 25

Figure 9-3 - ISO Risk Contour of KHDS .................................................................................................... 26

Figure 9-4 - ISO Risk Contour of HGU ...................................................................................................... 26

Figure 9-5 - ISO Risk Contour of ISOM ..................................................................................................... 27

Figure 9-6 - Combined ISO Risk Contour .................................................................................................. 27

Figure 9-70 – Radiation on a Plane for Pool Fire for IGHDS tank ............................................................. 28

Figure 9-8 – Radiation on a Plane for Pool Fire for IGHDS tank ............................................................... 28

Figure 9-9 - Radiation on a Plane for Pool Fire for IGHDS tank ................................................................ 29

Figure 9-10 - Radiation on a Plane for Pool Fire for ISOM tank ................................................................ 29



Figure 9-13 - Radiation on a Plane for Pool Fire for ISOM tank (203-TK-046/047) .................................. 30






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Figure 9-16 - Radiation on a Plane for Pool Fire for ISOM tank 203-TK-018-019_BS-VI HGU FEED

TANK .......................................................................................................................................................... 31

Figure 9-17 - Radiation on a Plane for Pool Fire for ISOM tank 203-TK-018-019_BS-VI HGU FEED

TANK .......................................................................................................................................................... 32

Figure 9-18 - 700 ppm of H2S due to 250 mm leak is not reaching beyond boundary limits of IOCL. ..... 34

List of Tables Table 1-1 – Details of Units with Capacities ................................................................................................ 8

Table 2-1 - Equipment Modification Details ............................................................................................... 11

Table 4-1 - Unit wise type of Risk .............................................................................................................. 19

Table 5-1 - Wind Velocity ........................................................................................................................... 22

Table 5-2 - Wind Direction and Percentage of Time for Each Quadrant ................................................... 23




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Abbreviations IOCL Indian Oil Corporation Limited

RRA Rapid Risk Assessment

DHDT Diesel Hydrotreating Unit

DHT Diesel Hydrotreating Unit (

HGA Hydrogen Generation Unit

IGHDS Indmax Gasoline Hydrodesulphurization

HCU Hydrocracker unit

KHDS Kerosene Hydro Desul Furization Unit

ISOM Isomerization Unit

HCN Heavy Cracked Naphtha

LCN Light Cracked Naphtha

MMTPA Metric Tons Per Annum

ALARP As Low As Reasonably Practicable

PSA Pressure Swing Absorption

ROG Refinery Offgas streams

SHU Selective Hydrogenation Section

UFL Upper Flammable Limit

LFL Lower Flammable Limit

HSE Health Safety & Environment

U

Million Metric Tons Per Annum

Adsorption

Unit




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Executive Summary

1. From the Risk Contours it is observed that in most cases of process units, the e-6 contour is

contained within boundary limits of IOCL. And hence it is within acceptable limits.

2. All the tanks are atmospheric and well with in the boundary of the facility. Being liquid the

credible fire scenarios include Pool fire and Full surface fire. The 37.5 kW heat radiation from

these fire does not extend beyond facility boundary.

3. In case of KHDS unit, the H2S concentration of 700 ppm does not extend beyond boundary

limit.of the facility even with 250 mm leak. It is demonstrated in figure 9-18. 1

37.5 kW/m2 heat radiation

from these fire does not extend beyond facility boundary.

all units




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1 Introduction 1.1 Background

Indian Oil Corporation Ltd. (herein after referred to as The Client) is planning to make their Paradip

Refinery compliant to produce 100% BS-VI MS and HSD products. Paradip Refinery is the latest refinery

of Indian Oil Corporation Limited (IOCL) and has a design crude processing capacity of 15.0 Million

Metric Tons Per Annum (MMTPA). The various units of the refinery is being commissioned stage-wise

and the refinery is presently under stabilization.

To make Paradip refinery of IOCL BS-VI compliant, there is a need for installation of new units and also

revamp of old units to produce 100% BS-VI MS and HSD complaint products.

ThyssenKrupp Industrial Solutions, India (tkIS) (hereinafter referred to as The Contractor) is appointed as

detailed engineering contractor for this project.

As part of this project, The Contractor is required to submit Rapid Risk Assessment Report (RRA). Bell

Energy, Bell Engineering Software Technologists Ltd,(hereinafter called The Consultant) an organisation

well known in the field of HSE has been assigned the work of preparation of RRA study report.

1.2 Purpose of RRA The purpose of RRA is to identify the Hazards at the early stages of development of project, analyze the

hazards and propose the preventive and mitigative measures where necessary, to bring the risk level to

As Low As Reasonably Practicable (ALARP)

1.3 Project Description The basic objective of the Project is to up-grade the Paradip Refinery for producing 100% BS-VI quality

fuels by inducting new units and/or revamp of existing units. Following units with capacities as under are

planned to be implemented:

Table 1-1 – Details of Units with Capacities

Sr. No. Unit Capacities for BS-VI (TMTPA)

1. ISOM-new 1100

2. INDMAX–GDS-new 1150

3. HGU-new 60 kTPA **

4. Kero HDS-new 300

5. DHDT-existing 20% revamp

6. VGO-HDT- existing Quality revamp - Change of catalyst.

New HGU will include 1 no. Pressure Swing Absorption (PSA). For refinery off gas treatment

another PSA is considered.




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The scope further includes Storage, dispatch facilities, Utilities & other off-site facilities. All the above

units & facilities will be integrated with Paradip Refinery.




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The Overall plot plan of the facility is presented below.

Figure 1-1 – Overall Plot Plan

Figure 1-2 – Overall Plot Plan




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2 Project Description 2.1 Process Description of DHDT Unit

This process description section provides explanation for the changes in equipment to be able to process

additional HSD feed in the Diesel Hydrotreater (Unit 013) at Indian Oil Corporation Limited in Paradip,

India. The Unit 013 is originally designed for 15000 tpd, with the additional feed the unit throughput will

increase by 20% to 18000 tpd.

For the revamped case, the feedstock to the Diesel Hydrotreating Unit (DHT) is a mixture of kerosene,

AGO, VGO, coker gas oil and Heavy Cracked Naphtha (HCN), LCO, HCO from the FCC and HSD from

VGO HDT.

These feedstocks enter the DHT Unit through four separate lines before being mixed ISBL:

• AGO, VGO and Kerosene from the AVU

• Coker Gasoil from the DCU

• LCO, HCN and HCO from the FCC

• HSD from the VGO HDT

Due to the increase of throughput, the following equipment will need likely need to be modified. Rating of

the existing vendor data sheets is needed to confirm.

Table 2-1 - Equipment Modification Details

013-C-001 Product Stripper Tray modifications

013-C-004 LP Amine absorber Tray modifications

013-P-001A/B/C Feed Charge Pump Increased impeller size

013-P-005A/B Diesel Product Pump Increased impeller size

013-E-004A/B Diesel Product Trim Cooler Tube modifications

Due to changes in the Product Diesel Flashpoint specification to min 42°C, the wild naphtha can be kept

in the Diesel Product which maximizes the diesel yield. This additional yield recovery will require

modification of the following additional equipment — a rating of the existing vendor data sheets is

needed to confirm.

013-C-002 Vacuum Drier Tray modifications

013-P-007A/B Drier Recycle Pump Tray modifications Pump

013-E-006A/B Drier Overhead Condenser Tube modifications




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2.2 Process Description of HGU Unit The plant design is based on Naphtha and Natural Gas as main feedstocks and an additional Refinery

Offgas streams (ROG). Naphtha and Natural Gas will be processed in Hydrogen Generation Unit (HGU),

while ROG will be processed in ROG PSA Unit.

The purge gas from the PSA purge gas from the HGU will be the primary fuel to the reformer furnace and

naphtha, natural gas or refinery fuel gas from BL will serve as the supplementary fuel.

The purge gas from the Refinery Offgas PSA will be exported to Refinery fuel gas header as per client`s

request.

The HGU consists of the following major process steps:

• Naphtha Pre-treatment

• Feed Treatment

• Steam Reforming

• CO Shift Conversion

• H2 Purification by Pressure Swing Adsorption (PSA)

• Process Steam and Condensate System

The ROG PSA consists of the following major process steps:

• ROG Compression

• H2 Purification by Pressure Swing Adsorption (PSA)

• Fuel Gas Compression

The design of the whole complex is based on modern, environmental friendly, reliable process steps for

dependable and uninterrupted operation with ease of operation and safety as key elements.

2.3 Process Description of IGHDS Unit

2.3.1 Selective Hydrogenation Section (SHU): Two FCC gasoline cuts are processed in the Prime G+TM unit. The LCN cut (C5- 70°C) which is

available at 40°C and the MCN cut (70 – 185°C) which is available at 128°C and contains impurities such

as Chlorine.

The SHU reactor R-101 operates in down-flow mode at moderate temperature, mainly under liquid phase

and achieves the following functions:

The SHU reactor R-101 operates in down-flow mode at moderate temperature, mainly under liquid phase

and achieves the following functions:

Diolefins removal from the full range FCC gasoline:

From the light fraction LCN cut it helps achieving better stability of this product sent to the

gasoline pool.




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From the heavy fraction HCN in order to prevent eventual fouling problems in the downstream

selective HDS section and achieving long catalyst cycles in line with FCC turnarounds.

Conversion of light mercaptans and light sulfides to heavier sulphur compounds, which are

recovered in the heavy cut HCN. The light cut produced by the LCN Splitter has therefore very

low sulphur content, does not require a sweetening and can be sent directly to gasoline pool,

The SHU effluent is directly sent to the LCN Splitter C-101.

2.3.2 LCN and MCN Splitters Section: The LCN splitter is reboiled by means of a heater. It produces as vapor distillate a sweet hydrogen rich

gas to be routed to fuel gas network.

The MCN splitter operates at lower pressure. It produces an intermediate cut MCN as liquid distillate -

essentially C6s rich in benzene and olefins and with moderate sulphur content- that will be routed to the

Mild MCN HDS section.

2.3.3 Selective HCN HDS Section – 1 stage HDS scheme: MCN splitter bottoms (HHCN) is mixed with hydrogen make-up and recycle gas and heated by heat

exchange against effluent before entering the Main HCN HDS reactor, R-201. The reactor

temperature is controlled by the bypass on the HDS feed/effluent E-201 heat exchanger.

Hydrodesulphurization reactions and limited olefin saturation take place in the two beds reactor operating

in down-flow mode and in vapor phase.

An injection of liquid quench is foreseen between the catalytic beds of the Main HCN HDS reactor in

order to limit the temperature rise due to the heat of reaction and control olefins saturation.

2.3.4 Selective MCN HDS Section – 1 stage HDS scheme: MCN splitter top distillate (MCN) is mixed with hydrogen make-up and recycle gas and heated by heat-

exchange against effluent in the exchanger E-301 before entering the Main MCN HDS reactor, R-301.

The reactor temperature is controlled by the duty of the MCN HDS Heater H-301.

Hydrodesulphurization reactions and limited olefin saturation take place in the two beds reactor operating

in down-flow mode and in vapor phase.

2.3.5 HCN and MCN Stabilizer Sections: H2S and light ends removal in the hydrodesulphurization heavy and medium gasolines is carried out in

the stabilizer columns C-202 and C-301 respectively.

The HCN stabilizer C-202 is reboiled by the reboiler E-203 using the HCN HDS Effluent as heating

medium and by E-204 on HP Steam for the remaining duty required. It produces a sour vapor distillate

and sweet desulphurized heavy gasoline HCN. The sour vapor distillate will have to be treated OSBL for

H2S removal to produce a sweet purge gas effluent before being routed to Fuel Gas system.

The MCN stabilizer C-301 is reboiled by the reboiler E-305, using the bottom of MCN Splitter as heating

medium. MCN Stabilizer products are a sour vapor distillate and a medium cut gasoline MCN that will




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have to be splitted downstream to get rid of the benzene and sulphur prior to being incorporated into the

MS pool.

2.4 Process Description of ISOM Unit The Penex process is specifically designed for continuous catalytic Isomerization of light naphtha. The

reactions take place in a hydrogen atmosphere, over a fixed bed of catalyst, and at operating conditions

that promote Isomerization and minimize hydrocracking.

Moderate operating conditions are used in the Penex process. The low operating temperature (120 to

175ºC) enables the Penex process to achieve the highest normal paraffin conversion. Ideally, the

Isomerization catalyst would convert the feed paraffin’s to the highest-octane number branched

structures: C5 to iso-pentane and C6 to 2,3- dimethylbutane. However, the Isomerization reactions are

equilibrium limited with lower temperatures favoring the concentration of highly branched isomers. When

operating at typical commercial conditions the ratios of iso to normal paraffin’s in the reactor effluent will

be approximately 3 to 1 and 9 to 1, respectively, for pentane and hexane. Ring opening is partially

promoted and the reactor effluent will contain less C6 naphthene than the feed. The C5 paraffin

equilibrium mixture will consist of essentially only normal and iso pentane; there is no formation of neo-

pentane. The C6 iso-paraffin equilibrium distribution is split approximately 45/55 between the higher

octane dimethylbutanes and lower octane methyl pentanes.

The first reactor may, therefore, be operated at a higher temperature and achieve a higher reaction rate.

This reduces the inventory of catalyst and the reactor size required. Most of the Isomerization is

accomplished at a high rate in the first reactor and the final portion is performed at a lower temperature

taking advantage of the more favorable equilibrium.

The standard Penex design since 1987 has been the Hydrogen-Once-Through (H-O-T) design. In this

unit, there is no recycle compressor, product condenser nor product separator.

Organic chloride promoter is added continuously with the feed and is converted to hydrogen chloride in

the reactor. Since the catalyst functions with small amounts of promoter (measured in parts per million), it

is not necessary to provide separate equipment for recovery and reuse of hydrogen chloride. It is

permitted to leave the unit by way of the stabilizer gas. The quantity of stabilizer gas is small, due to the

selective nature of the catalyst that permits very little hydrocracking of the light naphtha charge to take

place. The stabilizer gas contains the excess hydrogen required for plant control and the C1-C3

hydrocarbons introduced by way of the make-up hydrogen. The stabilizer off gas is scrubbed for

hydrogen chloride removal before entering the refinery fuel gas system.

The catalyst itself is non-corrosive and, despite the presence of small amounts of hydrogen chloride

during operation, the dryness of the system permits construction with carbon steel. Over thirty years of

commercial service have demonstrated the adequacy of this inexpensive metallurgy.




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2.5 Process Description of KHDS Unit Hydrodesulphurization reactions occur when hydrogen reacts with the sulphur atom and forms hydrogen

sulphide. The rate of reaction depends upon the type of sulphur compound present in SR Kerosene fuel

are mercaptans, thiophene and its derivatives, benzothiophene, small amounts of benzothiophene

derivatives etc.

Below are the different sections covered in this unit:

• Feed Section

• Preheat Train and Wash water section

• Feed Heater and Reactor Section

• LT Separator and RG Amine Absorption Section

• Recycle gas compressor section

• Stripper Section

• Sour Gas Amine Absorption Section




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3 Types of Risk 3.1 Flammable Gas Dispersion

If the Flammable gas released due to loss of containment forms a vapor cloud. If the flammable

concentration of the cloud while between upper flammable limit (UFL) and lower flammable limit (LFL)

does not get ignition source then the cloud loses its ability to catch fire and results in to harm less

dispersion (If no toxic substance is not present).

3.2 Toxic Gas Dispersion

In case of Toxic gas cloud, the fatal concentration if reaches ground level (1 m) it can affect human

beings.

3.2 Flash Fire Flammable gas released due to Loss of Containment, has the potential to form a flammable vapor cloud.

The cloud starts drifting either due to momentum or wind speed and direction. If it finds a credible ignition

source, due to delayed ignition of the flammable gas cloud, a flash fire can occur in an uncongested

area.

3.3 Vapor Cloud Explosion Upon release in the absence of immediate ignition sources, flammable gas forms a flammable vapor

cloud. Upon finding a credible ignition source, delayed ignition of the flammable gas cloud can lead to an

unconfined vapor cloud explosion if the gas is accumulated in a congested area, as no confinement is

identified for the project facilities. The degree of blast is dependent upon the congestion and the confined

volume.

3.4 Jet Fire Jet fires can occur due to immediate ignition of the released flammable gas or delayed ignition of the HC

vapor cloud flashing back leading to a jet fire scenario at the release location. This applies to the small

leak sizes (e.g. less than 100mm) of flammable material where the release from small opening causes

molecule atomization and due to friction can catch fire. If it does not catch fire, it can form liquid spray of

small droplets.

3.5 Pool Fire. Pool fire can occur due to immediate or delayed ignition as a result of liquid pool formation. The size of

the pool fire will be governed by liquid burning rate. For tank facilities, full surface fire and bund fire can

occur.

3.5.1 Surface Fire Surface fire can occur in case of tank roof failure and the substance stored in the tank catches fire.

3.5.2 Bund Fire. The liquid pool formed as a result of loss of containment from a bunded tank can vaporize and get an

ignition source and resultantly catch fire




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4 Methodology Adapted The Methodology adapted for the purpose od this RRA is as follows;

1. Study process description of the units involved.

2. Study Lay out, Piping & Instrumentation diagrams, Process Flow diagrams and Heat and

Material balance.

3. The P & Ids were used for the purpose of sectionalisation and parts count.

4. Based on the properties of the material consequence analysis were performed.

5. Using failure frequencies, the risk analysis was carried out.

6. The results have been compared with the risk acceptance criteria.

7. The study considers all the loss of containment cases for the leak sizes as mentioned in the

Assumptions and Study basis.

For the purpose of simulation Phast for Consequence Analysis and Phast Risk software for Risk Analysis

has been used.

PFDs




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5 Considerations for Disaster Management Plan. These units are close to the water (Lake or river) and if the same is used for transportation /

travelling, people need to be made aware the flammable and Toxic risk they are exposed to and

what emergency actions are needed.

An Escape and Evacuation plan including Muster location is needed for these people are.

Since these units contain hydrocarbon and are part of a refinery, the disaster management plan of

the existing refinery should be adequate to cater to the requirements of this section also. If not then

these actions need to be integrated in to existing DMP after checking.

Since the facility includes H2S, H2S zoning analysis and its implementation should be considered.

.




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6 Hazards Identification The units concerned here are basically Hydrocarbon processing units operating at high temperatures

and high pressures. Like any other refineries, the main risk is flammable risk. In KHDS Unit, the Toxic

material i.e. H2S. is present However it is very less than the fetal concentration of 700 ppm.In some

other streams / Unit Benzene and Toluene in small ppm is present. However, the risk from Benzene

depends upon the continuous exposure. This is termed as “Occupational health issue” and not

instantaneous health (fatality) issue.

Unit wise type of Risk

Table 6-1 - Unit wise type of Risk

Sr Unit Description. Substance Type of Risk

1 HGU Naphtha, Natural

Gas, Hydrogen

Flammable Flash Fire

Vapor Cloud

Explosion

2 KHDS H2S, HC Toxic Flammable

3 ISOM Naphtha, HC Flammable

4 IGDHS Hydrogen, HC Flammable Explosion

5 DHDT HC Flammable

The flammable consequences normally do not extend beyond boundary wall. The boundary walls

themselves offer protection from flammable consequences. These consequences of these are

considered in calculating risk.




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7 Risk Acceptance Criteria. For this study, the Risk Acceptance Criteria of UK HSE and adapted by India is considered.

Figure 7-1 – Risk Acceptance Criteria




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8 Assumptions and Study Basis 8.1 Following assumptions and basis of study were made :

S. No. Category Sub-

Category Assumption Justification

1 Vessel Volume

Calculated based on vessel dimension, assuming 100% full. For simplification, assuming that vessel in cylindrical shape. Only vessel type either vertical and horizontal are considered with inventory, others e.g. heat exchanger, pump, ejector, etc. have no static inventory as it is similar to others, considered as piping volume

2 Parts Count PFDs are used for the parts count as P&IDs are not available at this stage. Assumptions: 1. 2 flanges per valve (manual or actuated) 2. Pipng, valve, flanges size are considered to be 10" as no P&IDs yet available 3. Each piping length inlet and outlet of vessel is assumed 20m

P&IDs are not available

3 Failure Frequency

OGP database failure frequency will be adopted

4 Release hole size

Hole sizes are based on OGP recommended range and hole size 1. 1 - 10 mm, representative as 5mm (small leak) 2. 10 - 50 mm, representative as 25 mm (medium leak) 3. 50 - 150 mm, representative as 100mm (Large leak) 4. > 150 mm, full bore rupture, piping diameter of 10"

Company criteria is not available

5 Consequence Modelling

General - Surface Roughness

1.0 as large refinery with large obstacles as per PHAST definition

General - Ambient Temp.

27 deg C

General - Operating Pressure

Based on provided H&MB, streams and PFD

IGHDS & ISOM - Operating

Consider Operating pressures as 0.9 times Design Pressures of the respective equipment. Design pressures of equipment referred to the

(Except for IGHDS and ISOM Units)




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S. No. Category Sub-

Category Assumption Justification

Pressure Licensor in Equipment list

General - Operating Temperature

Based on provided H&MB, streams and PFD

IGHDS & ISOM - Operating Temperature

Consider Operating Temperature as 25 °C lower than the Design Temperatures of the respective equipment. Design Temperatures of equipment will refer to the Licensor in Equipment list

6 Wind speed and stability

2F for night

5D for daytime Windrose

distribution Paradip Refinery, refer to the provided PFDs

7 units IGDS and ISOM,

following operating conditions have been assumed in absence of Heat and Mass Balance:

Operating Pressure: 0.9 times operating pressure of respective equipment as given by licensor. Operating Temperature: 25 Deg C lower than the operating temperature as indicated by Licensor

For IGDS unit, equipment tag numbers and inter equipment distances have been assumed based on the process description and past experience for similar project as the same are not provided by Licensor.

8.2 Meteorological data.

Wind Table 8-1 - Wind Velocity

Average velocity

- Summer 37 – 45 km/hr

- Winter 15 – 26 km/hr

Maximum velocity 72 m/sec (259 km/hr)(During 1999 cyclone)

- cyclone 200 - 250 km/hr (S-SE)

Basic wind speed for structural design 65 m/sec (234 km/hr)

(Except for IGHDS and ISOM Units)




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Table 8-2 - Wind Direction and Percentage of Time for Each Quadrant

% of time

N

NE

E

SE

S

SW

W

NW

Calm

Morning (0830)

13.8 6.4 2.1 2.4 7.7 21.6 11.0 8.2 (∆26.8)

Evening (1730) 15.0 6.7 9.41 8.16 15.0 24.8 4.8 1.8 (∆27.8)




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9 Conclusions and Recommendations 1. The combined Risk Contour demonstrates that the general public is exposed to ( as this is RRA

which concentrates on general public) less than e-6 which is within Broadly Acceptable region.

when compared with UK HSE Risk Acceptance Criteria as adapted by India.

2. From the Risk Contours it is observed that in most cases of process units, the e-6 contour is

contained within boundary limits of IOCL. And hence it is within acceptable limits.

3. All the tanks are atmospheric and well with in the boundary of the facility. Being liquid the

credible fire scenarios include Pool fire and Full surface fire. The 37.5 kW heat radiation from

these fire does not extend beyond facility boundary.

4. Fn Curve: Since the risk more than e-5 is not extending beyond facility boundary, the Fn curve is

not relevant

5. All the tanks are atmospheric tanks. Being liquid the credible fire scenarios include Pool fire and

Full surface fire. It is noted that heat radiation (37.5 kW and 12 kW ) from these fire does not

travel beyond facility boundary

6. Company should get H2S zoning done in areas having high H2S

37.5 kW/m2

(37.5 kW/m2 & 12 kW/m2)




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Annexure ISO Risk Contour od DHDT unit.

Figure 9-1 - ISO Risk Contour of DHDT unit. It can be seen from the above Risk Contour that the e-6 contour is well within the boundary of the facility.

ISO Risk Contour of IGDHS unit.

Figure 9-2 - ISO Risk Contour of IGDHS unit. It is evident from the risk contour that the contour of e-6 is well within the boundary of the facility.




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ISO Risk Contour of KHDS

Figure 9-3 - ISO Risk Contour of KHDS It can be seen from the LSIR contours that e -6 contour is well within the boundary limit of the facility.

ISO Risk Contour of HGU

Figure 9-4 - ISO Risk Contour of HGU It can be noted from the above LSIR contour, that e-6 contour is confined with in the boundary of the

facility.




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ISO Risk Contour of ISOM

Figure 9-5 - ISO Risk Contour of ISOM The e-6 contour is well within the boundary of the facility.

Combined ISO Risk Contour The combined LSIR also e-6 risk contour does not extend beyond boundary limit.does not

Figure 9-6 - Combined ISO Risk Contour




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It may be noted that combined e-6 Risk Contour does not extend beyond facility boundary.

Tanks.

All the tanks are atmospheric tanks. Being liquid the credible fire scenarios include Pool fire and Full

surface fire. For the purpose of RRA, it is necessary to check heat radiation from these fire whether it

extends beyond facility boundary or not. (37.5 kW)

IGHDS tank.

Tank details: Diameter = 37.6m Height = 19m Operating Temp: 40degC Operating Press = atm pressure

Figure 9-70 – Radiation on a Plane for Pool Fire for IGHDS tank

Figure 9-8 – Radiation on a Plane for Pool Fire for IGHDS tank The thermal radiations level modelled = 4, 12.5 and 37.5 kW/m2.

(37.5 kW/m2)




Version: A 16.02.2018

Findings = 12.5 and 37.5 do not reach 2 m height and ground level. 4 kW/m2 can reach and extend

approximately 73m away from tank.

IGHDS Tanks

Figure 9-9 - Radiation on a Plane for Pool Fire for IGHDS tank

ISOM Tanks.

Figure 9-10 - Radiation on a Plane for Pool Fire for ISOM tank




Version: A 16.02.2018

Figure 9-11 - Radiation on a Plane for Pool Fire for ISOM tank

Figure 9-12 - Radiation on a Plane for Pool Fire for ISOM tank ISOM (203-TK-046/047)

Figure 9-13 - Radiation on a Plane for Pool Fire for ISOM tank (203-TK-046/047)




Version: A 16.02.2018



203-TK-018-019_BS-VI HGU FEED TANK

Figure 9-16 - Radiation on a Plane for Pool Fire for ISOM tank 203-TK-018-019_BS-VI HGU FEED TANK




Version: A 16.02.2018

Figure 9-17 - Radiation on a Plane for Pool Fire for ISOM tank 203-TK-018-019_BS-VI HGU FEED TANK

Similarly SKO Product storage Tank has been modelled and the Thermalradiation is found within the stipulated limit of 37.5 KW/m2 at the facilityboundary limit.




Version: A 16.02.2018

Annexure a

PROJECT DESCRIPTION

The basic objective of the Project is to up-grade the Paradip Refinery for producing 100% BS-VI quality

fuels by inducting new units and/or revamp of existing units. Following units with capacities as under are

planned to be implemented:

Sr. No. Unit Capacities for BS-VI (TMTPA)

1. ISOM-new 1100

2. INDMAX–GDS-new 1150

3. HGU-new 60 kTPA **

4. Kero HDS-new 300

5. DHDT-existing 20% revamp

6. VGO-HDT- existing Quality revamp - Change of catalyst.

** New HGU will include 1 no. Pressure Swing Absorption (PSA). For refinery off gas treatment another

PSA is considered.

The scope further includes Storage, dispatch facilities, Utilities & other off-site facilities. All the above

units & facilities will be integrated with Paradip Refinery.




Version: A 16.02.2018

700 ppm of H2S due to 250 mm leak is not reaching beyond boundary limits of IOCL.

Figure 9-18 - 700 ppm of H2S due to 250 mm leak is not reaching beyond boundary limits of IOCL.