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CCPSCenter for Chemical Process Safety

An AIChE Technology Alliance Risk Analysis Screening Tools (RAST) Overview / Demonstration

March 19, 2020 Slide - 1

Risk Analysis Screening Tools (RAST)

Case Study – T2 Industries


An AIChE Technology Alliance

Runaway Reaction and Explosion

Jacksonville, Florida

December 19, 2007




Case Study – T2 IndustriesHazard Identification and Risk Analysis (HIRA) Study

What are the Hazards?

What can go Wrong?

How Bad could it Be?

How Oftenmight it

Happen?

Is the Risk Tolerable?

Identify Chemical

and ProcessHazards

Estimate Frequency

Analyze Consequences

AnalyzeRisk

IdentifyAdditional Safeguards as Needed

DevelopScenarios

Identify Equipment

or Activity to be Analyzed

Manage Barriers

for Life Cycle of Facility

We begin the study by Identifying the Equipment or Activity for which we intend to perform

an analysis. RAST uses the operation of a specific equipment item containing a specific

chemical or chemical mixture to define the activity. For example, the operation of a storage

tank, a reactor, a piping network, etc. Inputs are chemical data, equipment designinformation, operating conditions, and plant layout.





Process DescriptionWe have been asked to perform a HIRA study of the MCMT Process. Methylcyclopentadienyl

manganese tricarbonyl (MCMT) is an organo-manganese compound used as an octane-increasing

gasoline additive. The Ethyl Corporation originally developed MCMT in the late 1950s. T2

manufactured and sold MCMT under the trade name Ecotane.

MCMT is produced in three steps that occur sequentially within a single process reactor. In the first

reaction step (called metalation), the process operator feeds a mixture of methylcyclopentadiene

(MCPD) dimer and diethylene glycol dimethyl ether (diglyme) solvent into the reactor. An outside

operator then hand-loads blocks of sodium metal through a 6-inch gate valve on top of the reactor,

closing the valve when complete. The process operator then heats the mixture with the hot oil

piping system, setting reactor pressure control at 3.45 bar and hot oil temperature control at 182oC.

Intended Chemistry:

This is an illustrative example and does not reflect a thorough or complete study.





Process DescriptionThe initial reaction mixture contains approximately 0.11 weight fraction sodium, 0.45 weight

fraction MCPD dimer and 0.44 weight fraction diglyme solvent. Heating this mixture begins the

metalation reaction by melting the sodium and splitting each MCPD dimer molecule into two

MCPD molecules. The melted sodium then reacts with the MCPD to form sodium

methylcyclopentadiene, hydrogen gas, and heat. The hydrogen gas vented to the atmosphere

through the pressure control valve and 1-inch vent line.

Once the mixture temperature reaches 99oC, the process operator starts the agitator. The mixing

and higher temperature acts to increase the metalation reaction rate. At a reaction temperature of

about 149oC, the process operator turns off the hot oil system and heat generated by the

metalation reaction continues to raise the mixture temperature. At a temperature of about 182oC,

the process operator initiates the control system cooling program, which intermittently injects water

into the jacket based on the rate of reaction temperature increase. The heat of reaction for this

step is approximately -45.4 kJ/mol sodium, -1975 J/g sodium, or -217 J/g reaction mixture.





Process Description

Diagram of MCMT Reactor Process Control Screen for MCMT Reactor






We will start by entering information for the MCMT Reactor. At some point, we may decide

to include other equipment in the study.

One the Main Menu, enter the equipment identification as the MCMT Reactor, equipment

type as Stirred Reactor/Crystallizer and location as Outdoors.

Chemical Data – RAST requires a chemical or chemical mixture that is representative of the

hazards. RAST does not perform time-dependent or location-dependent composition

changes (such as within a reactor or distillation column). Where hazards may be

significantly different between reactor feed and products, or distillation overheads versus

bottoms; evaluation of the equipment may be repeated using different composition (such as

Reactor A with feed composition and Reactor B with products composition).



Import from Previous Study

Merge Data from Another Study into this Study

Update Previously Saved Information

Access LOPA Workbook from Scenario Results

Update Notes and Comments for Entire Workbook

Select Default Units: Study File: Case Study - T2 Industries Example.xlsm

Session Date: Participants:

Equipment Identification =

Equipment Type =

Equipment Location =

Data Entry Status or Notes:

Plant Section or Sub-Area:

P&ID Number:

Min

Complete

RAST

Input Data Sufficient to Proceed with Analysis

Input Information

Stirred Reactor/Crystallizer

Outdoors

MCMT Reactor

Evaluations and Reports

Risk Analysis Screening Tools (V 2)Latest Revision Date 3/02/19

Import from RAST File

Equipment Parameter Input

Chemical Data Input

Reaction Input and Evaluation

Fire & Explosion Index / Chemical Exposure Index

English Units SI Units

Relief Effluent Screening

Scenario Identification

Check Inputs

Save Inputs toEquipment Table

Go to Equipment Table >

Process Conditions Input

Plant Layout Input

Hazards & Consequences

LOPA Menu >

Clear Input

Update Scenarios for Equipment Loaded

Input Guidance Information

CLEAR EVERYTHING IN WORKBOOK

Pool Fire Evaluation

Merge Data from Another File

Go to Workbook Notes >

Go to Revision Log >

Go To Scenario Results >

Go To Instructions >>


Enter Equipment Identification,

Equipment Type and Location



Begin by entering

information on the

Main Menu worksheet.

Start with the MCMT

Reactor






Diglyme solvent and Methylcyclopentadiene

Dimer (MCPD) are major components of the

feed but not listed in the RAST chemical data

table, so we will enter this as a new

chemical. Many companies have access to

large chemical property databases that

contain the information we will need. In

other cases, vendor Safety Data Sheets,

Cameo Chemicals (US National Oceanic and

Atmospheric Administration), or literature

references may be used. It is good to look

for agreement among multiple sources.



Chemical PropertiesStarting Chemical That

is SimilarUser Supplied Values

Properties of User

Chemical to be Saved

Chemical Name = Dowanol EB (2-

butoxyethanol)Diglyme

CAS Number = 111-76-2 111-96-6 111-96-6

Data Source:Data per Cameo, Molbase

SDS and ThermoFisher

Scientific SDS

Mol Weight = 118.2 134.2 134.2

Melting Point, TM (C) = -77 -64 -64

Boil Point, TB (C) = 170.7 162 162

Vap Pres A = 10.876 10.302

Vap Pres B = 4185.21 4038.32

Vap Pres C = 59.3 43.0 Property Units Point 1 Point 2

Dens A = 0.921 0.964 0.964 Temperature 1 and 2 C 25 162

Dens B = 0.00094 0.00094 Vapor Pressure (absolute) mmHg 3 760

Liq C A = 0.544 0.544 Liquid Density Kg/cu m

Liq C B = 0.00094 0.00094 Liquid Heat Capacity J/gm C

Lat Ht A = 119.3 119.3 Heat of Vaporization J/gm

Lat Ht B = 0.185 0.185

Lat Ht C = 0.00016 0.00016 Estimated Boiling Point, C = 162.0

Flash Pt (C) = 65 55 55

LFL (Vol %) = 1.13 1.5 1.5

UFL (Vol %) = 17.4 17.4

AutoIgnition Temperature (C) = 170 170

Ease of Ignition = Normal Normal

Fuel Reactivity = Medium Medium

Liquid Conductivity

Dust Deflagration Class

Solids Mean Particle Size (micron)

Solids Part Size at 10% Fract (micron)

Dust Min Ignition Energy (mJ)

Dust-Flam Vapor Hybrid?

ERPG-1 or Odor (ppm) = 20

ERPG-2 (ppm) = 20 91 91

ERPG-3 (ppm) = 700 190 190

NFPA Health = 2 0 0

NFPA Flammability = 2 2 2

NFPA Reactivity = 0 0 0

Dermal Toxicity =

Aquatic Toxicity = Harmful NA NA

Reactivity Category =

Good Warning Properties?

User Chemical Data Input

Calculate Physical Property Constants from Data Points

Save Chemical Data to Chemical TableClear Chemical Data Inputs< Go To Chemical Data

Go To Chemical Table to Delete User Chemical >


Select “Add New Chemical” from the

Chemical Data worksheet to access

the “New Chemical” worksheet. Start

with “Diglyme”

Since the information available from

common sources is very limited, we

will start with data from a chemical

with nearly the same molecular weight

and boiling point (2-butoxyethanol),

then update with what little we know.

Save as “diglyme”. RAST uses

relatively simple correlations for

chemical properties that require only

one or two data points.

Information Sources

may be noted

The normal boiling

point and vapor

pressure at 25 C from

Molbase SDS

Liquid density, liquid heat

capacity and heat of vaporization

for 2-butoxyethanol were used

Flash Point, Flammable Limits,

NFPA Ratings and ERPG (in this

case PAC) concentrations are

from Cameo Chemicals

Started with chemical

information for 2-butoxyethanol


Chemical Data



Chemical PropertiesStarting Chemical That

is SimilarUser Supplied Values

Properties of User

Chemical to be Saved

Chemical Name = Triethylbenzene (mixed

isomers)

Methylcyclopentidiene

Dimer

CAS Number = 25340-18-5 25340-18-5

Data Source:Cameo, Molbase SDS,

ThermoFisher Scientific SDS

Mol Weight = 162.28 160.26 160.26

Melting Point, TM (C) = -51 -51

Boil Point, TB (C) = 218.4 200 200

Vap Pres A = 10.639 8.430

Vap Pres B = 4781.94 3624.76

Vap Pres C = 42.3 43.0 Property Units Point 1 Point 2

Dens A = 0.890 0.890 Temperature 1 and 2 C 47.8 200

Dens B = 0.00078 0.00078 Vapor Pressure (absolute) mmHg 7.5 760

Liq C A = 0.396 0.396 Liquid Density Kg/cu m

Liq C B = 0.00102 0.00102 Liquid Heat Capacity J/gm C

Lat Ht A = 90.3 90.3 Heat of Vaporization J/gm

Lat Ht B = 0.081 0.081

Lat Ht C = 0.00010 0.00010 Estimated Boiling Point, C = 200.0

Flash Pt (C) = 83 26 26

LFL (Vol %) = 1 1 1

UFL (Vol %) = 5.6 10 10

AutoIgnition Temperature (C) =

Ease of Ignition =

Fuel Reactivity =

Liquid Conductivity

Dust Deflagration Class

Solids Mean Particle Size (micron)

Solids Part Size at 10% Fract (micron)

Dust Min Ignition Energy (mJ)

Dust-Flam Vapor Hybrid?

ERPG-1 or Odor (ppm) = 3 0.34 0.34

ERPG-2 (ppm) = 33 3.7 3.7

ERPG-3 (ppm) = 195 21 21

NFPA Health = 0 0

NFPA Flammability = 2 3 3

NFPA Reactivity = 0 0

Dermal Toxicity =

Aquatic Toxicity =


Good Warning Properties?

User Chemical Data Input

Calculate Physical Property Constants from Data Points

Save Chemical Data to Chemical TableClear Chemical Data Inputs< Go To Chemical Data

Go To Chemical Table to Delete User Chemical >


Select “Add New Chemical” from the

Chemical Data worksheet to access

the “New Chemical” worksheet.

Since the information available from

common sources is very limited, we

will start with data from a chemical

with nearly the same molecular weight

and boiling point (triethyl benzene),

then update with what little we know.

Save as “Methylcyclopentidiene

Dimer”. RAST uses relatively simple

correlations for chemical properties

that require only one or two data

points.

Information Sources

may be noted

The normal boiling

point and vapor

pressure at 25 C from

Molbase SDS

Liquid density, liquid heat

capacity and heat of vaporization

for triethyl benzene were used

Flash Point, Flammable Limits,

NFPA Ratings and ERPG (in this

case PAC) concentrations are

from Cameo Chemicals

Started with chemical

information for triethyl benzene


Chemical Data



Chemical Data Input

Equipment Identification: 150 C

Equipment Type: 3.45 bar

Location: 256.3 C

Key Chemical: Reference:

Chemical Comments:

Reg. Agency Considers Toxic?

Methylcyclopentidiene Dimer 0.450 0.317 0.4565 160.26 3.7 21 1.0

Diglyme 0.440 0.679 1.0000 134.2 91 190 1.5

Dissolved Solids 0.110 0.003 0.0196 100

Sum = 1.00 Vapor Mixture Properties: 141.3 12.0 58.5 1.3

Mixture azeotrope? No

Melting Point = -64 deg C

Flash Point = 26 deg C

Est Mixture Flash Point = 51.9 deg C with high uncertainty

1 Not “Sustained Burning”?

AutoIgnition Temperature = 170 deg C

Ease of Ignition = Normal

Fuel Reactivity = Medium

Dermal Toxicity =

Aquatic Toxicity =

Model as a single Pseudo-Chemical? Mixture NFPA Flammability = 3

Mixture NFPA Health = 0


Mixture NFPA Reactivity = 0

Estimated Boiling Point = 180.4 C Liquid Conductivity =

Vapor Pressure at Operating Temp = 0.468 atm

Liquid Density at Operating Temp = 0.84 gm/ml

Liq Heat Capacity at Op Temp = 0.60

Liq Heat Capacity at Boiling Point = 0.63 micron

Heat of Vaporization at Op Temp = 83 micron

Heat of Vaporization at Boiling Point = 77 mJoule

Boiling Point at Relief Set or MAWP = 404.4 C

Boiling Point at Burst Pressure = 535.3 C

From the above vapor composition: Estimated 1 hour LC 1 117.1 ppm Estimated 1 hour LC 50 292.6 ppm

State Mol Weight ERPG-2 (ppm) ERPG-3 (ppm) LFL (vol %) Flash Pt (C )

Pad Gas Properties Vapor 2.02 230000 400000 4 -259

Heat Transfer Fluid

Summary of Chemical Properties

cal/gm C

Standard Mixture (the key chemical has been

defined as a mixture)

Dust CharacteristicsDust/Solids Hazard Class =

Solids Mean Particle Size =

cal/gmDust Min Ignition Energy =

Name

Hydrogen

Dust-flammable hybrid?

Particle Size at 10% Fraction =

Solids Bulk Density >160 g/liter (>10 lb/ft3)?

Liquid

Operating Temperature =

Methylcyclopentidiene Dimer Cameo, Molbase SDS, ThermoFisher Scientific SDS

MCMT Reactor

Outdoors


Second Liq

Phase

Chemicals (the first chemical listed is the 'key'

chemical)

Wt Fraction

Feed

Saturation Temperature =

Physical State =

Operating Pressure (gauge) =

Use "Dissolved Solids" to represent the Sodium Metal which has extremely low vapor pressure. Add a small amount of

hydrogen such that the saturation temperaure is slightly above the operating temperature

User ValuesMixture

Estimates

ERPG-3 (ppm)ERPG-2 (ppm) LFL (vol %)

Mixture Properties

Wt Fraction

Feed

Molecular

Weight

Second Liq

Phase

Relative

Volatility

Wt Fraction

Vapor

High Viscous Material (for F&EI)?

Go To Process Conditions >Save All Input to Equipment TableEnter New Chemical Clear Input

<< Go To Main Menu

Go To Plant Layout >

Show Chemical Details Hide Chemical Details

Go To Equipment Input >



Chemical Data

Saturation temperature is

estimated and physical

state as “liquid”

A composition (weight fraction):0.45 Methylcyclopentadiene Dimer

0.44 Diglyme

0.11 Dissolved Solids

(representing Sodium metal)

was used as representative of the

initial charge to the reactor.

The operating pressure was

entered as 3.45 barg and the

operating temperature was entered

as 150 C.

RAST allows up to 5

components.

Chemical details may

be shown or hidden

The operating pressure

entered as the initial

pressure set pressure.

Hydrogen as the Pad Gas is

entered on the Process

Conditions worksheet



Equipment Input

Equipment Identification:

Equipment Type:

Location:

2500 gal Pipe Length = m

41 bar Piping Vulnerable to Damage?

Apply Screwed Connection Penalty?

C

C

100 mm Pump Type =

Seal or Containment Type =

Remote Start Pump?

11198 kg Pump Automated Suction or Discharge?

kg Estimated User Entry

Pump Volume (including piping to block valves), liter 15.1

Pump Surface (including piping to block valves), m2 0.69

Kwatt

Fireproof

Equipment or Piping Connection =

21 sq m

sq m Replacement Cost & Business Loss

m Drum Oven Volume = cu m

mm High Speed Rotating Equipment?

Bellows or Expansion Joint Used?

Sight Glass Used?

Relief Device Identification

Relief Type =

Relief Discharges to:

Relief Set Pressure (gauge) = 28 bar

sq m Relief Size (equiv. diameter) = 100 mm

Kwatt /sq m C Relief Design Actual Flow Rate = kg/min

182 C Release Pipe Diameter = mm

bar Release Elevation m

Closest Distance From Relief to Elevated Work Area = m

Heat Transfer Fluid Name = Furthest Distance from Relief to Elevated Work Area = m

Elevation of Nearest Work Area = m

Enter Distances from Relief Location ONLY if Different from Equipment Location

mm Relief Distance to Property Limit or Fence Line = m

Relief Distance to Occupied Bldg 1 or Area = m

15 sq m Relief Distance to Center of Occ Bldg 1 = m

0.2 Kwatt /sq m C Occ Bldg 2 in Same Wind Direction for Relief?

100 C Relief Distance to Occupied Bldg 2 = m

Relief Distance to Center of Occ Bldg 2 = m

Low Pressure Tank with Weak Seam Roof?

Coolant Temperature =

Conductive Dip Pipe or Bottom Fill?

Cooling Transfer Area =

Tube (or Leak) Diameter =

Quantity Hot Oil Handled (for F&E) =

Cooling Overall U =

Number of Tubes =

Relief Device Parameters

Heat Transfer Parameters

Heating Overall U =

Heat Transfer Fluid Pressure (gauge) =

Vessel/Tank Considered as "Storage"?

Other Equipment Parameters

Transportation Equipment or Piping Parameters

Tube Failure Release to Atmosphere?

Insulation

Estimated Equipment Max Wetted Area =

Heating Fluid Temperature =

Heating Transfer Area =

Rupture Disk

Tracing ?

Vessel/Tank Geometry?

Insulation Heat Reduction Factor =

Material of Construction

Internal Corrosive or Stress Cracking Potential?

Equipment Mass =

Number of Flanges or Nozzles =

Nozzle or Pipe Size =

Estimated Equip Mass based on C. Steel

Equipment Elevation to Surface =

Drain Valve Size

MCMT Reactor

Outdoors

Susceptible to Vibration Fatigue?

Motor Power =

User Equipment Max. Wetted Area =

Heat Transfer Fluid State =

Vessel/Tank Parameters

Piping Parameters

Pump / Agitator Parameters

MAWP (gauge) =

Equipment Description

Equipment Volume =


Equipment Parameters

Full Vacuum Rated?

Estimated High Temperature Failure =

Estimated Embrittlement Temperature =

Clear InputSave Input to Equipment Table< Go To Chemical Data

<< Go To Main Menu Go To Process Conditions Input >

Go To Plant Layout >

Go To Reaction Input >



Equipment Input

The reaction equipment is a 2450

gallon vessel with a Maximum

Allowable Work Pressure (MAWP) of

600 psig (41 bar). The cooling

surface area is approximately 160 ft2

(15 m2) and cooled with evaporating

water at 100 C. Assume a heat

transfer coefficient for the jacked of

0.2 kwatt/m2 C. The hot oil heating

media temperature is 182 C and the

vessel is insulated.

Only minimal data will be entered at

this time.

The equipment volume

and maximum allowable

working pressure

A 4 inch (100 mm) nozzle is

assumed the largest liquid

connection to the vessel.

Information related to heat

transfer of the equipment

The reactor was equipped

with a 4 inch (100 mm)

rupture disk set at 28 barg

(400 psig)





Process ConditionsThe maximum flowrate during the methylation

reaction step is zero (all is added batchwise

at the start of reaction). We can evaluate the

loading step by entering the equipment

information with a separate identification

(such as MCMT Reactor-loading). The

temperature and pressure conditions during

this step would be different from the reaction

step.

Hydrogen has been entered as the pad gas

since it is a reaction product not present

initially. (Also, the flash routines in RAST do

not handle trace amounts of highly volatile

component in the liquid phase.)



Equipment Type:

Location:

Ambient Temperature = Operating Temperature = 150 C

Inventory Limit (blank is unlimited) = kg Operating Pressure (gauge) = 3.45 bar

Liquid Head within Equipment, Dh = m Physical State =

Limiting Maximum Fill Fraction = Saturation Temperature = 256.3 C

Limiting Minimum Fill Fraction = Contained Mass = 6357 kg

Maximum Feed Press (gauge) = bar Maximum Contained Mass = 7946 kg

Maximum Feed or Flow Rate = 0 kg/min Inventory for Reference = 7946 kg

Maximum Feed Temperature = C

Type of Feed (Batch or Continuous)

Non-Ignitable Atmosphere Maintained?

Potential for Aerosol or Mist?

Pad Gas Name = Percent of Time in Operation =

Max Pad Gas Pressure (gauge)= bar

Maximum Pad Gas Rate = kg/min

Downstream Pressure (gauge) = bar

Maximum Back Flow Rate = kg/min

Equipment Vents to .. =

Use Time-based Release for Equipment Rupture? sec

Liquid

Review Date:

Review of Operating Procedures for

Selected Equipment Item by:

Centralized Ventilation Shut-Off Bldg 1?

Centralized Ventilation Shut-Off Bldg 2?

Frequent Turnaround or Cleanout?

Hydrogen

Operating Procedures

MCMT Reactor


Process Description

Process/Operating Conditions

Outdoors

Summary for Methylcyclopentidiene Dimer

Clear InputSave Input to Equipment Table< Go To Chemical Data

Go To Plant Layout ><< Go To Main Menu

< Go To Equipment Input

Go To Reaction Input >

Note that with an entry of

zero federate, no overfill

scenario will be suggested.





Site Layout

The manufacturing facility is located on

a 5 acre site north of a Jacksonville,

Florida industrial area. A small control

building is located roughly 50 ft (15 m)

from the reactor with up to 10

occupants. There is a trucking

company and other businesses

adjacent to the T2 site, roughly 140 m

away with possibly 20 occupants.

Plant Layout Input


Equipment Type:

Location:

Distance to Property Limit or Fence Line = 100 m Occupied Building 1 Name =

Furthest Distance to Fence Line ( > 100 m ) = m Distance to Occupied Bldg 1 or Area = 15 m

Max. Onsite Outdoor Population Density people/m2 Elevation of Occ Bldg 1 Ventilation Inlet = m

Personnel Routinely in Immediate Area? Distance to Center of Occupied Bldg 1 = m

Distance to end of Offsite Zone 1 m Occupied Bldg Type =

Offsite Population Density within Zone 1 people/m2 Occupied Bldg Ventilation Rate = changes/hr

Offsite Population Density Beyond Zone 1 people/m2 Number of Building Occupants = 10

Effective Egress from Work Area? Occ Bldg 2 in Same Wind Direction? No

Access for Emergency Services? Occupied Building 2 Name =

Degree of Equipment Congestion in Area? Distance to Occupied Bldg 2 140 m

Containment or Dike Surface Area = sq m Elevation of Occ Bldg 2 Ventilation Inlet = m

Consider Dike or Bund Failure for Vessel Rupture? Distance to Center of Occ Bldg2 = m

Credit Fire Heat Adsorption for Drainage/Indirect? Occupied Bldg 2 Type =

Distance to Nearest Fired Equipment = Occupied Bldg 2 Ventilation Rate = changes/hr

Quantity of "Other" Flammables in Immediate Area kg Number of Occupants Bldg 2 = 20

Quantity of Flammables in Adjacent Area kg

Adjacent Containment or Dike Surface Area = sq m

Automated EBVs to limit spill quantity?

Spills to Soil Require Remediation?

Potential for Water Contamination?

Enclosed Process Volume = cu m High Population Downstream of Facility?

Enclosed Process Ventilation = changes/hr

No. Enclosed Area Personnel =

MCMT Reactor


Outdoors

Layout Description

Note that Environmental Scenarios are Excluded

Enclosed Process Area Data

Occupied Building DataLocation Information

Environmental Inputs

Warehouses and Adjacent Businesses

Control Room

Clear InputSave Input to Equipment Table< Go To Process Conditions

Go To Reaction Input ><< Go To Main Menu


< Go To Chemical Data



Reaction Data Input and Evaluation

Physical State = Liquid

No

Table / User User Value

-52 -52

25 25

150 150

0.2 0.2

0.002 2.00E-03

Theoretical Theoretical

cal/g mix-min

Typically < 1.0

Yes

2 Typically > 1.0

Britton's Method, Z = 1.18 Potential = LOW

watt / m C

cm

Kcal/gm mole

0.92 atm

gm mole/cc mix

Initial Temperature = 150.0 C Rate at Initial Temp = 0.1207 cal/gm-min

Max Adiabatic Temp = 235.3 C Reactivity Parameter = 2.9

Max Adiabatic Pressure = 228.21 atm Insulated? Fireproof

Temperature (C) TMR Time to Relief at 404.4 deg C Temp of No Return, TNR = >TNR C Convective HT Coefficient = 0.0005 Kwatt/sq m C

150 71.1 70.4 Minutes TNR with Cooling = 170.479023 C

180 11.4 10.7 Minutes

100 2.1 2.1 Days

150 71.1 70.4 Minutes

Potential for Insulation or Packing Fire

Assess Reactive Scenarios Only?

Equipment Tag = MCMT Reactor

Key Chemical = Methylcyclopentidiene Dimer

Time to Maximum Rate at Specified Starting Temperatures

Reactivity Data Input

Detected Rate, R0 (C/min) =

Thermal Inertia (ARC or other), f =

Estimated Gas Generation, k =

Reactants in Separate Liquid Phase?

Gas Generation, k (g mole/cc mix) =

Inhibited Monomer?

Temperature, C

Fraction of Reaction Heat for "Pooling"

Potential Mis-Loading of Reactants?

Multiple of Reaction Heat for Mis-Loading

Material Thermal Conductivity

Estimation of Frank-Kamenetskii Critical Diameter (Slab)

Limiting Reaction Rate =

Test Method =

Heat of Reaction, DHR (cal/g mix) =

Activation Energy, DE (Kcal/g mole) =

Detected Onset, T0 (C) =

Gas Generation precedes Exotherm?

Potential for Mixing Incompatible Materials?

Considered Condensed Phase Explosive?

Potential Catalyzed Reaction?

Potential for "Pooling" of Reactants?

Intended reaction for this Equipment?

Intended Exothermic Reaction (for F&EI)

Intended Endothermic Reaction (for F&EI)

Data Reference:

Observed Rate, C/min

Fraction Conversion

Activation Energy =

Reaction

Estimation of Gas Generation

Reaction Scenario Type =

Observed Press (atm abs) and Temp (C)

Estimated Vapor Pressure + Inert Pad

Reaction Screening Calculations

F-K Critical Diameter at 150 deg C

Estimation of Activation Energy from ARC Data

0.0001

0.001

0.01

0.1

1

10

100

0 50 100 150 200 250 300 350

Hea

t R

ate

(cal

/gm

min

)

Temperature (oC)

Reaction Heat Gain or Cooling Loss versus Temperature(Exothermic Reaction Assuming First Order Kinetics)

Adiabatic Reaction Heat Rate Convective Heat Loss Rate

Maximum Cooling Capacity Reaction-Thermal Initiated plus Heat

Reaction Plus Fire Reaction with Catalyst plus Heat

Reaction with Pooling plus Heat Reaction with Mis-Loading plus Heat

0.1

1

10

100

1000

0 50 100 150 200 250 300 350 400 450

Pre

ss

ure

(atm

-a

bs

olu

te)

Temperature (oC)

Reaction Pressure versus Temperature(Adiabatic Exothermic Reaction Assuming First Order Kinetics)

Pressure - Adiabatic Rx Vapor Pressure

Pressure-Rx Thermal Initiated plus Heat Pressure-Rx with Fire

Pressure-Rx with Catalyst plus Heat Pressure-Rx with Pooling plus Heat

Pressure-Rx with MisLoading plus Heat Relief Set Pressure

Save Reaction Data to Chemical Table < Go To Plant Layout

<< Go To Main Menu

Save Input to Equipment Table< Go To Chemical Data


< Go To Process Conditions



Reaction InputEach ml of reaction mixture contains 0.84 g

and roughly 0.09 g sodium or 0.004 gmole.

From the reaction stoichiometry, 0.5 mole

hydrogen is evolved per mole of sodium or

0.002 gmole hydrogen per ml of reaction

mixture.

The known heat of reaction for the

methylation step is -217 J/g or -52 cal/g

reaction mixture. The activation is assumed

a typical value of 25 to 30 kcal/gmole.

Finally at temperature rise rate of 0.2 C/min

is assumed at 150 C such that it would take

approximately 60 minutes for the reaction

mass to heat from 150 to 180 C.

Reaction parameters

are entered. Ideally,

experimental values or

a kinetic model would

be available.

The maximum reaction

pressure far exceeds the

MAWP of the reactor.

However, the rate of pressure

rise would be such that the

vent system would normally be

capable of handling it.

Dashed green line is the

cooling capability of the

reactor jacket





Reaction EvaluationIn addition to the chemical hazards of flammability and toxicity, there are significant hazards

associated with the methylation reaction. It is exothermic such that loss of temperature

control will allow the reaction to proceed more quickly than the equipment may be designed

for. Secondly, the reaction includes a gaseous product (hydrogen) such that extremely high

pressure could be attained (far greater than the design limits of the equipment) if the system

is not properly vented.

Another process upset to consider would be misloading of the initial materials, particularly the

diglyme solvent. If there is less solvent to adsorb the reaction heat, the maximum reaction

temperature would be higher with a corresponding higher reaction rate. (Note the “yes” to

misloading with a multiple of 2 on the heat as solvent is nearly 50% of the initial charge.)

There is very little reaction information available to better understand what might happen

under upset conditions suggesting that additional reactive chemicals testing should be done.






Input Data for an Equipment Item

stored in one row by Equipment Tag

Retrieve Information for an Equipment

Item by selecting any cell in the desired

row and entering Load Selected

Select Save Inputs to Equipment Table (blue macro button). All Input Information

will be stored in the Equipment Table in a single row identified by a unique Equipment

Identification or Tag.




Risk Matrix


To understand the Consequence

Severity and Tolerable Frequency, the

values for key Study Parameters and a

Risk Matrix may be viewed on the

Workbook Notes worksheet. These

values may be updated on hidden

worksheets and should reflect the

company’s specific risk criteria.

For this case study, the Risk Matrix

(right) has been used. The Human

Harm criteria is based on an estimated

number of people severely impacted

(severe injury including fatality).

2 3 4 5 6 7

Description Human Harm Environment Business Loss 10^-2/year 10^-3/year 10^-4/year 10^-5/year 10^-6/year 10^-7/year

Reportable Incident to Environmental Agency OR

< 10 kg Very Toxic to Waterway OR < 100 kg NFPA-H4 to Soil

< 100 kg Toxic to Waterway OR < 1000 kg NFPA-H3 to Soil

< 1000 kg Harmful to Waterway OR < 10000 kg NFPA-H2 to Soil

Environmental Contamination Confined to Site OR




Environmental Contamination of Local Groundwater OR




Incident Requiring Significant Off-Site Remediation OR



> 100000 kg Harmful to Waterway OR > 100000 kg NFPA-H2 to Soil

Incident with Significant National Media Attention OR


> 100000 kg Toxic to Waterway OR > 1000000 kg NFPA-H3 to Soil

Acceptable

Tolerable - Offsite

Tolerable - Onsite

Unacceptable

Low

Con

sequ

ence

Hig

h

Con

sequ

ence

Low

Frequency

High

Frequency

Consequence Severity Description Frequency

Severity Level-1

Minor Injury On-site

(or < 0.01 Person Severely Impacted On-site)

Potential for Adverse Local Publicity

Property Damage and

Business Loss < $50M2 Orange Yellow

Green

Green

Yellow> 10 People Severely Impacted On-site

> 1 Person Severely Impacted Off-site

Property Damage and

Business Loss > $50 MM6 Red

Red Red Orange Yellow GreenSeverity Level-41 to 10 People Severely Impacted On-site

0.1 to 1 People Severely Impacted Off-site

Property Damage and

Business Loss $5 MM to

$50 MM

Legend

6

Yellow Green GreenSeverity Level-2

Major Injury On-site

(or 0.01 to 0.1 Person Severely Impacted On-site)

Public Required to Shelter Indoors

(or Minor Injury Off-site)

Property Damage and

Business Loss $50 M to

$500 M

3 Red

Red Orange Yellow GreenSeverity Level-3

Potential Fatality On-site

(or 0.1 to 1 Person Severely Impacted On-site)

or Potential Major Injury Off-site

Property Damage and

Business Loss $5 MM to

$50 MM

4 Red

Severity Level-5

6

Red Orange

5 Red

Risk Matrix: Risk = Consequence Severity times Frequency

Red Red

Green Green Green Green

Orange



Evaluation Date(s) and

Participant Names are

entered on the Main Menu

Analysis Team captures which

Scenarios warrant more

Detailed Evaluation (Layers of

Protection Analysis)

Session Date: Session Participants:

LOPA Menu Filters:

Scenario Type Scenario CommentsParameters and

DeviationInitiating Event (Cause) Initiating Event Description Loss Event Outcome

Off-S

ite T

oxic

Rel

ease

On-S

ite T

oxic

Rel

ease

Indo

or T

oxic

Rel

ease

Toxi

c In

filtra

tion

Chem

ical

Exp

osur

e

Flas

h Fi

re o

r Fire

ball

Vapo

r Clo

ud E

xplo

sion

Build

ing

Expl

osio

n

Equi

pmen

t Exp

losi

on

Prop

erty

Dam

age

or B

usin

ess

Loss

Envi

ronm

enta

l Dam

age

I

n

c

Existing Safeguards RecommendationsFurther

Analysis

Drain or Vent Valve Open

Drain or Vent Valve left open

following infrequent maintenance,

purging or cleaning

Flow-Loss of

Containment

Human Failure Action once per

quarter or less

Operator leaves Drain or Vent Open

following infrequent maintenanceDrain or Vent Leak

Off-Site Toxic Release, On-Site Toxic

Release, Toxic Infiltration, Chemical

Exposure, Flash Fire or Fireball

4 4 6 4 4

I

n

c

l

u

d

Plant requires blind flange or

plug for all terminal connections

to the atmosphere

Yes

Seal Leak No Agitator Seal indicatedFlow-Loss of

ContainmentSingle Mechanical Seal Failure

Failure from corrosion, alignment,

low flow, etc.

Mechanical Seal Failure above

Liquid Level

On-Site Toxic Release, Indoor Toxic

Release2 2

I

n

c

l

u

d

Relatively low consequence

severityNo

Vapor Relief Vent - ReactionOff-Site Toxic Release, On-Site Toxic

Release, Toxic Infiltration6 5 6

I

n

c

l

u

Equipment Rupture at Saturation

Temperature



Exposure, Flash Fire or Fireball,

Vapor Cloud Explosion, Equipment

Explosion

4 4 2 4 4 5 6

I

n

c

l

u

d

e

d

Vapor Relief Vent - Reaction with

Fire


Release, Toxic Infiltration, Flash Fire

or Fireball, Vapor Cloud Explosion

3 4 4 4 5

I

n

c

l

u

d

e

Equipment Rupture at Fire

Conditions



Exposure, Flash Fire or Fireball,

Equipment Explosion

3 4 4 4 5 6

I

n

c

l

u

d

e

d

Excessive Heat Input - Heat

Transfer

Vapor Pressure plus pad gas Does

Not exceed Maximum Allowable

Working Pressure or Relief Set

Pressure at Ambient or Heating

Media Temperature

Pressure-High BPCS Instrument Loop Failure Failure of Flow ControlCriteria for Triggering Incidents

Not Met

E

x

c

l

u

d

e

Excessive Heat Input - Pool

Fire Exposure

Scenario is addressed as Fire

Induced ReactionPressure-High

IEF=3 pending more detailed

evaluation

Leak of Flammable Material or

Material above its Flash Point which

may ignite

Criteria for Triggering Incidents

Not Met

E

x

c

l

u

Excessive Pad Gas Pressure

Maximum Pad Gas Pressure Does

Not Exceed the Maximum Allowable

Working Pressure or Relief Set

Pressure

Flow-High Regulator FailureRegulator Fails causing high flow or

pressure


Not Met

E

x

c

l

u

d

High Temperature Failure

Maximum Feed Temperature Does

Not Exceed Temperature limits of

Equipment

Temperature-High BPCS Instrument Loop Failure Failure of Temperature ControlCriteria for Triggering Incidents

Not Met

E

x

c

l

u

d

e

Ignitable Headspace

Chemical is Flammable or

Combustible: Maximum Operating,

Mechanical Energy or Heating Media

Temperature exceeds Flash Point

less 5 C

Composition-Wrong

ConcentrationBPCS Instrument Loop Failure

Failure of Pressure or

NonCombustible Atmosphere

Control


Not Met

E

x

c

l

u

d

e

d

BPCS Instrument Loop FailureFailure of Level Indication with

continued addition of material

E

x

c

l

u

Human Failure Action more than

once per quarter

Operator opens wrong valve or

initiates filling when equipment is not

empty

E

x

c

l

Pad Gas Compression

Maximum Feed or Downstream

Pressure does not exceed the

Maximum Allowable Working

Pressure or Relief Set Pressure

Pressure-High BPCS Instrument Loop Failure Failure of Pressure ControlCriteria for Triggering Incidents

Not Met

E

x

c

l

u

d

e

Piping or Equipment Leak -

Small

Assessment Excludes Mechanical

Integrity Scenarios

Flow-Loss of

ContainmentMechanical Failure

Loss of Alignment or Equipment

Support causing Vibration or

Excessive Movement


Not Met

E

x

c

l

u

d

Rotating Equipment DamageMotor Power below Rotating

Equipment Vibration or Damage Limit

Composition-

ContaminantsMechanical Failure

Breakage of rotating blade or internal

parts due to alignment, wear,or

fatigue


Not Met

E

x

c

l

u

d

Vacuum Damage Equipment is rated for Full Vacuum Pressure-Low BPCS Instrument Loop Failure Failure of Pressure ControlCriteria for Triggering Incidents

Not Met

E

x

c

l

u


Not Met

Uncontrolled Reaction - Fire

Induced

Overfill or Overflow

Overfill or Backflow of liquid with spill

rate equal to the feed rate to a

maximum quantity of the available

inventory minus contained mass

Reaction-High Rate

Level-High

IEF=3 pending more detailed

evaluation

Leak of Flammable Material or

Material above its Flash Point which

may ignite

Exothermic Reaction or formation of

gaseous products with Potential from

Fire Heat Input

Evaluate Relief Device for

runaway reactionYes

Yes

Uncontrolled Reaction -

AdiabaticBPCS Instrument Loop Failure

Loss of Cooling results in

Uncontrolled Exothermic Reaction

Operating Temperature exceeds the

Temperature of No Return and

Maximum Reaction Pressure may

exceed the equipment Maximum

Allowable Working Pressure or

Relief Set Pressure

Reaction-High Rate

Plant Section = T2 Laboratories

Equipment Tag = MCMT Reactor-with decomposition

Scenarios with NO IPL's Required will NOT be reported. Off-S

ite T

oxic

Rel

ease

Flas

h Fi

re o

r Fire

ball

Chem

ical

Exp

osur

e

Toxi

c In

filtra

tion

Indo

or T

oxic

Rel

ease

On-S

ite T

oxic

Rel

ease

Missing Inputs for Session Date or Participants

Suggested Scenarios from the RAST Library

Scenarios in gray were suggested to

be excluded for reason noted under

Scenario Comments. Study Team

should review each to determine if

excluding from Risk Analysis is

appropriate.

MCMT Reactor-with decomposition is a Stirred Reactor/Crystallizer containing

Methylcyclopentidiene Dimer Mix that operates at 150 C and 3.45 bar. The volume is

2500 gal with a maximum allowable working pressure of 41 bar. The maximum feed

or flow rate is 0 kg/min.

Potential Outcome / Tolerable Frequency

Factors

Envi

ronm

enta

l Dam

age

Prop

erty

Dam

age

or B

usin

ess

Loss

Equi

pmen

t Exp

losi

on

Vapo

r Clo

ud E

xplo

sion

Build

ing

Expl

osio

n

Node Design Intent Summary:

Mechanical Integrity Scenarios will NOT be

reported

Evaluation Node:

Equipment Type = Stirred

Reactor/Crystallizer

Update List

Go To Scenario Results ><< Go To Main Menu

Create UserScenario

Update Input this worksheet

Clear Input this Worksheet

Save Input to Equipment Table



Suggested Scenarios for the MCMT Reactor

A very serious scenario is overpressure and

rupture of the MCMT Reactor from an

uncontrolled reaction. Even if the vent system

can prevent the rupture, venting flammable

and toxic gases may also be an issue.

RAST is also suggesting the Vapor Cloud explosion may be a

concern from the sudden release of flammable material if the

vessel ruptures. However, the vapor may immediately ignite if the

release is above the AutoIgnition temperature or from sparks

emitted during rupture leading to fire rather than explosion.

The high consequence

severity for the uncontrolled

reaction scenarios also

suggest that additional reactive

chemicals testing and/or

evaluation is warranted.

Analysis Team captures

Existing Safeguards and

Recommendations for

Scenarios Identified

Once Inputs are Entered

use “Update Input this

Worksheet” to Save

Additional Scenarios

are Added using

“Create User Scenario”





Suggested Scenarios for MCMT Reactor

WORKING WITH YOUR EVALUATION TEAM:

❑ Review the suggested list of scenarios. Do these represent what you

would expect for a batch reactor?

❑ Are there scenarios that have been “screened out” (shown in gray) that

should be considered?

❑ Are there scenarios missing? (Possibly similar scenarios with different

Initiating Events)

❑ Do you agree with the “worst” Consequence (Tolerable Frequency

Factor) for the scenario listed?





Suggested Scenarios for MCMT Reactor

WORKING WITH YOUR EVALUATION TEAM:

❑ Utilize an Appropriate Hazard Evaluation Technique (HAZOP, What If, etc.)

to capture additional scenarios.

❑ Capture existing Safeguards and Recommendations for each Scenario.

Note the Dates and Names of participants in the Study.

❑ Select which Scenarios warrant more detailed Risk Evaluation (such as

Layers of Protection Analysis).



RAST Version 3

Explosion Summary:

VCE or Building Explosion Energy, kcal 2.4E+07

VCE or Building Explosion Distance to 1 psi Overpressure, m 312.4

Maximum Distance to LFL Concentration, m

Blast Overpressure at Center of Occupied Building 1, psi 6.6

Blast Overpressure at Center of Occupied Building 2, psi 2.3

Distance to Severe Thermal Radiation Impact, m

Rupture Explosion Energy, kcal 4.6E+05

Distance to Direct Blast Impact (10 psi), m 27.6 2

Maximum Fragment Range, m 876.2

Rupture Distance to 1 psi Overpressure, m 130.0

Rupture Overpressure at Center of Occupied Building 1, psi > 10 psi

Rupture Overpressure at Center of Occupied Building 2, psi 0.9

Incident Outcome and Consequence Summary:

3

Onsite Toxic Impact based on Distance to LC-50 Concentration of 33 m Yes 4

Outdoor Toxic Exposure Duration 28 sec

Onsite Flash Fire Impact based on Distance to 0.5 LFL Concentration of 30 m 4

Chemical Exposure based on Dermal or Thermal Hazards and Spray Distance of 74 m 4

Equipment Rupture Direct Blast Impact based on Distance to 10 psi of 27.6 m Yes 4

Onsite Thermal Radation Impact based on Distance from Fireball

Number of Potential Serious Toxic Impacts Onsite: 0.1 people

Number of Potential Serious Flash Fire/Fireball Impacts Onsite: 0 people

Occupied Building Toxic Impact No 2

Number of Potential Serious Impacts for Building 1: 0 people


Occupied Building Impact from Vapor Cloud Explosion Yes 5



1 psi Blast Overpressure Distance exceeds the Fence Line, Consider additional Offsite Impacts

Occupied Building Physical Explosion Impact Yes 6


Number of Potential Serious Impacts for Building 2: 0.1 people

1 psi Blast Overpressure or Max Fragment Distance exceeds the Fence Line, Consider additional Offsite Impacts

Environmental Impact: NA

Estimated Number of

People Impacted

Probability of Ignition (POI)

Potential Explosion

Impact to Occupied

Building

Potential Equip

Rupture Impact to

Occupied Building

Probability of Explosion (POX)

LOPA Tolerable Frequency

Factors Based On

CONSEQUENCE SUMMARY Date:


Temperature

Loss Event for: Stirred Reactor/Crystallizer; MCMT Reactor

Containing Methylcyclopentidiene Dimer :

Impact Assessment with Personnel routinely in the immediate

area

Exceeds Threshold

Criteria

YesOffsite Toxic Impact based on Toxic Integration Method and 100 m to Fence Line

RAST Version 3

Release Location Outdoors

Airborne Quantity Summary:

Release Temperature, C 535.3 Factor Probability

Release Pressure, barg 82.000

Physical State at Release Conditions Liquid

Heat Input, Kcal/min

Equivalent Hole Size, cm

Release Rate, Kg/sec Instantaneous

Release Duration, min

Total Release Quantity, kg

Spray Distance, m 74.0

Flash + Aerosol Evaporation Fraction 0.879

Estimated Aerosol Droplet Diameter, micron 10

Pool Area, sq m 94.8

Estimated Pool Temperature, C 50.2

Maximum Pool Evaporation Rate, kg/sec 0.0053

Total Airborne Rate, kg/sec

Total Airborne Quantity, Kg 4932.5

Airborne Quantity Composition:

Mole Fraction Methylcyclopentidiene Dimer 0.433

Mole Fraction Diglyme 0.542

Mole Fraction Dissolved Solids 0.025

Mole Fraction Pad Gas (at Mw = 2.02)

ERPG-2 for Vapor Composition, ppm by volume 91.7

ERPG-3 for Vapor Composition, ppm by volume 480.3

LC-50 Concentration, ppm by volume 2401.6

One-hour ERPG-3 for Vapor Composition, ppm by volume 42.6

One-hour LC-1 Concentration, ppm by volume 85.3

LFL for Vapor Composition, % by volume 1.26

Dispersion Summary (Atmospheric Stability Class D with 3 m/sec wind except as noted):

Max Distance to Time-Scaled ERPG-2, m 702.2

Max Distance to Time-Scaled ERPG-3, m 148.3

Max Distance to 1% Lethality for 1.5 F weather, m 99.8

Max Distance to Estimated LC-50 Concentration, m 32.7

Max Distance to Flash Fire Impact or 0.5 LFL, m 30.3

Maximum Ground Elevation Concentration, ppm 1000000.0

Concentration at Distance to Fence Line, ppm 730.9

Concentration at Distance to Unrestricted Work Area, ppm 1000000.0

Concentration within Occupied Bldg 1, ppm 64.0

Concentration within Occupied Bldg 2, ppm 6.0

Concentration within Enclosed Process Area, ppm

Conc within Enclosed Process Area w/Ventilation, ppm

Potential Flamm

Impact to Occupied

Building (Conc > 0.5

LFL at Building)

Potential Toxic

Impact within

Occupied Building

(Indoor Conc > one-

Prob of Exposure (proximity based)

Fence Line

Concentration

Exceeds ERPG-2

On-Site Toxic POE

Flash Fire POE

Chemical Exposure POE

Physical Explosion POE

CONSEQUENCE SUMMARY Date:


Temperature

Loss Event for: Stirred Reactor/Crystallizer; MCMT Reactor

Containing Methylcyclopentidiene Dimer :

Ground or Work Area

Exceeds Multiple of

LFL or Time-Scaled

ERPG-3

Equipment Rupture Modeled as Catastrophic Failure (Instatnaneous)

with Personnel Not in Immediate Area



Consequence AnalysisFor the MCMT Reactor, select

Rupture at Saturation as the

Loss Event. This represented a

“worst” Consequence for rupture.

(The maximum reaction

temperature is lower than the

estimated 522 C but greater than

the operating temperature.)

The distance to 1 psi

overpressure is estimated at 130

m and overpressure at the

distance to the control building is

estimated at >10 psi.The number of people severely impacted in

the control building and surrounding

businesses are significant.Blast Impacts are noted as extending

beyond the plant boundary





Consequence AnalysisWhat was unknown to the T2 owners is that the diglyme solvent decomposes exothermally at

elevated temperature in the presence of sodium or possibly sodium methylcyclopentadiene.

The heat of reaction and reaction rate at elevated temperature is such that the normal

hydrogen vent, cooling capability and the relief device are not effective. The uncontrolled

reaction scenario considering decomposition is a much higher risk as the heat generated in

the methylation reaction will cause the system temperature to reach that where the

decomposition proceeds at a very significant rate – only a loss of cooling is needed.

Heat of diglyme decomposition ~ -320 kJ/mol diglyme or -1050 J/g reaction mixture. This

may have sufficient energy for deflagration or detonation depending on peak reaction rate.

The activation energy from modeling is roughly 19 kcal/mol.




Following the incident at T2 Industries,

a VSP test was run for the typical

recipe with results used to create a

kinetic model. Test results indicated a

maximum temperature rate of

1300oC/min and maximum pressure

rate of 2200 bar/min with maximum

temperature of 650oC. These

conditions are well above the design

limits of the equipment. In addition, the

higher reaction rate evolves hydrogen

at a rate which likely far exceeds the

design of the vent system.


Consequence Analysis



Reaction Data Input and Evaluation

Physical State = Liquid

No

Table / User User Value

-251 -251

19 19

150 150

0.2 0.2

0.002 2.00E-03

Theoretical Theoretical

cal/g mix-min

Typically < 1.0

2 Typically > 1.0

Britton's Method, Z = 1.18 Potential = LOW

watt / m C

cm

Kcal/gm mole

0.92 atm

gm mole/cc mix

Initial Temperature = 150.0 C Rate at Initial Temp = 0.1207 cal/gm-min

Max Adiabatic Temp = 561.8 C Reactivity Parameter = 9.0

Max Adiabatic Pressure = 485.32 atm Insulated? Fireproof

Temperature (C) TMR Time to Relief at 404.4 deg C Temp of No Return, TNR = >TNR C Convective HT Coefficient = 0.0005 Kwatt/sq m C

150 93.6 93.6 Minutes TNR with Cooling = 180.057625 C

180 24.0 24.0 Minutes

100 25.1 25.1 Hours

150 93.6 93.6 Minutes

Potential for Insulation or Packing Fire

Assess Reactive Scenarios Only?

Equipment Tag = MCMT Reactor-with decomposition

Key Chemical = Methylcyclopentidiene Dimer

Time to Maximum Rate at Specified Starting Temperatures

Reactivity Data Input

Detected Rate, R0 (C/min) =

Thermal Inertia (ARC or other), f =

Estimated Gas Generation, k =

Reactants in Separate Liquid Phase?

Gas Generation, k (g mole/cc mix) =

Inhibited Monomer?

Temperature, C

Fraction of Reaction Heat for "Pooling"

Potential Mis-Loading of Reactants?

Multiple of Reaction Heat for Mis-Loading

Material Thermal Conductivity

Estimation of Frank-Kamenetskii Critical Diameter (Slab)

Limiting Reaction Rate =

Test Method =

Heat of Reaction, DHR (cal/g mix) =

Activation Energy, DE (Kcal/g mole) =

Detected Onset, T0 (C) =

Gas Generation precedes Exotherm?

Potential for Mixing Incompatible Materials?

Considered Condensed Phase Explosive?

Potential Catalyzed Reaction?

Potential for "Pooling" of Reactants?

Intended reaction for this Equipment?

Intended Exothermic Reaction (for F&EI)

Intended Endothermic Reaction (for F&EI)

Reaction Parameters based on Modeling of Willey, Fogler, and Cutlip of VSP experiment

Data Reference:

Reaction Parameters based on Modeling of

Willey, Fogler, and Cutlip of VSP experiment

Observed Rate, C/min

Fraction Conversion

Activation Energy =

Reaction

Estimation of Gas Generation

Reaction Scenario Type =

Observed Press (atm abs) and Temp (C)

Estimated Vapor Pressure + Inert Pad

Reaction Screening Calculations

F-K Critical Diameter at 150 deg C

Estimation of Activation Energy from ARC Data

0.0001

0.001

0.01

0.1

1

10

100

1000

0 100 200 300 400 500 600

Hea

t R

ate

(cal

/gm

min

)

Temperature (oC)

Reaction Heat Gain or Cooling Loss versus Temperature(Exothermic Reaction Assuming First Order Kinetics)

Adiabatic Reaction Heat Rate Convective Heat Loss Rate

Maximum Cooling Capacity Reaction-Thermal Initiated plus Heat

Reaction Plus Fire Reaction with Catalyst plus Heat

Reaction with Pooling plus Heat Reaction with Mis-Loading plus Heat

0.1

1

10

100

1000

0 100 200 300 400 500 600

Pre

ss

ure

(atm

-a

bs

olu

te)

Temperature (oC)

Reaction Pressure versus Temperature(Adiabatic Exothermic Reaction Assuming First Order Kinetics)

Pressure - Adiabatic Rx Vapor Pressure

Pressure-Rx Thermal Initiated plus Heat Pressure-Rx with Fire

Pressure-Rx with Catalyst plus Heat Pressure-Rx with Pooling plus Heat

Pressure-Rx with MisLoading plus Heat Relief Set Pressure

Save Reaction Data to Chemical Table < Go To Plant Layout

<< Go To Main Menu

Save Input to Equipment Table< Go To Chemical Data


< Go To Process Conditions



Updated Reaction Input

The VSP experimental data was fit to a

kinetic model to better understand the

behavior of the reaction during process

upsets. Reference Willey, Fogler and Cutlip;

“The Integration of Process Safety into a

Chemical Reaction Engineering Course:

Kinetic Modeling of the T2 Incident”,

Process Safety Progress 30 (2010).

A key finding is that if the rupture disk had

been set to a much lower pressure (maybe

100 psig), it may have had sufficient

capacity to prevent the rupture.

Note the much higher

reaction rate and final

temperature than form

the intended reaction

only.

Note the estimated point

where the reaction rate

exceeds the cooling capability

is 180 C. The plant routinely

operated without cooling to

190 C, so the kinetic

parameters or jacket heat

transfer coefficient may be

low. However, this indicates

that normal operation was very

close to the estimated

“temperature o no return”.




Updated Reaction InputThe MCMT reaction including the decomposition reaction information may be easily saved as

an additional equipment item. On the Main Menu, change the equipment ID to MCMT Reactor

–with decomposition. Then use the Save Inputs to Equipment Table macro button.

Import from Previous Study

Merge Data from Another Study into this Study

Update Previously Saved Information

Access LOPA Workbook from Scenario Results

Update Notes and Comments for Entire Workbook

Select Default Units: Study File: Case Study - T2 Industries Example.xlsm

Session Date: Participants:

Equipment Identification =

Equipment Type =

Equipment Location =

Data Entry Status or Notes:

Plant Section or Sub-Area:

P&ID Number:

Min

Complete

RAST

Input Data Sufficient to Proceed with Analysis

Input Information


Outdoors

MCMT Reactor-with decomposition

Evaluations and Reports

Risk Analysis Screening Tools (V 2)Latest Revision Date 3/02/19

Import from RAST File

Equipment Parameter Input

Chemical Data Input

Reaction Input and Evaluation

Fire & Explosion Index / Chemical Exposure Index

English Units SI Units

Relief Effluent Screening

Scenario Identification

Check Inputs

Save Inputs toEquipment Table

Go to Equipment Table >


Plant Layout Input

Hazards & Consequences

LOPA Menu >

Clear Input

Update Scenarios for Equipment Loaded

Input Guidance Information

CLEAR EVERYTHING IN WORKBOOK

Pool Fire Evaluation

Merge Data from Another File

Go to Workbook Notes >

Go to Revision Log >

Go To Scenario Results >

Go To Instructions >>

Note an addition input line on the Equipment

Table worksheet which contains the data for the

decomposition reaction while retaining the initial

equipment item with the intended reaction data.

Enter the updated

Equipment

Identification




March 19, 2020Slide - 27


Consequence Analysis – Physical ExplosionRAST estimate of Direct

Blast Impacts (10 psi

overpressure)

RAST estimate of 1 psi

Blast Overpressure

Damage to Conventional

Constructed Buildings

RAST estimate of 0.5

psi Blast Overpressure

Damage to Low

Strength Buildings

REPORT NO. 2008-3-I-FL , US Chemical Safety Board,

Figure 4. Injury and business locations.

RAST estimated a maximum

fragment range of 876 m (2870

ft). The reactor head was

found 400 ft away, the agitator

350 ft away, and support

columns 1000 ft from the

original location.

RAST estimated a blast energy

equivalent to 840 lb TNT (and

assumes ½ this energy is

consumed in rupturing the

vessel) versus CSB estimate of 1400 lb TNT equivalent.



Scenario Definition

Protection

Gap

Scenario /

Cross Ref

Description of Undesired ConsequenceLOPA Tolerable Frequency Factor

(chemicals, quantity involved,

and basis for calculations)

Initiating Event Probability of Ignition Probability of Exposure

(Presence Factor)

Time at Risk or Other

Enabling Factor

New

Instrumented

Protection

Credits

Taken

IPL Status? -->

Safety

AnalysisTolerable Frequency Factor 6 BPCS Instrument Loop Failure POE Probability Factor 0

5 1 94 6 1 0 0

Probability of Personnel to be

in Close Proximity to

Chemical Release based on

Physical Explosion Impact

Area to 876 m

152.01



Stirred Reactor/Crystallizer, MCMT Reactor-with

decomposition, is involved in an Uncontrolled

Reaction - Adiabatic event resulting in an Equipment

Rupture at Saturation Temperature with a Distance to

1 psi Overpressure of 130 m. Estimated time to

rupture is 94 min.

This incident could result in an Equipment

Explosion with Rupture Distance to Direct

Blast Impact (Overpressure or Fragments)

of 876 m including Rupture Overpressure at

Typical Construction Occupied Bldg 1 of

31.1 psi. 1 psi Blast Overpresssure

exceeds Distance to the Fence Line of 100

m. Consider adjustment for Off-Site Impacts

with the potential for Severity Level-5

< Back to Scenario Results

+

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> Human Error ++ +> Possible IPLs


Risk Analysis / Layers of Protection Analysis (LOPA)

March 19, 2020Slide - 28

The initial Initiating Event description

may be modified by the study team to

more clearly describe what happened

Select Loss Event Equipment

Rupture at Saturation with Incident

Outcome of Equipment Explosion

for analysis in LOPA (“Yes”), then

select LOPA Worksheet






Scenario Definition

Protection

Gap

Scenario /

Cross Ref

Description of Undesired ConsequenceLOPA Tolerable Frequency Factor

(chemicals, quantity involved,

and basis for calculations)

Initiating Event Probability of Ignition Probability of Exposure

(Presence Factor)

Time at Risk or Other

Enabling Factor

New

Instrumented

Protection

Credits

Taken

IPL Status? -->

Safety

AnalysisTolerable Frequency Factor 6 BPCS Instrument Loop Failure POE Probability Factor 0

5 1 94 6 1 0 0

Probability of Personnel to be

in Close Proximity to

Chemical Release based on

Physical Explosion Impact

Area to 876 m

152.01



Stirred Reactor/Crystallizer, MCMT Reactor-with

decomposition, is involved in an Uncontrolled

Reaction - Adiabatic event resulting in an Equipment

Rupture at Saturation Temperature with a Distance to

1 psi Overpressure of 130 m. Estimated time to

rupture is 94 min.

This incident could result in an Equipment

Explosion with Rupture Distance to Direct

Blast Impact (Overpressure or Fragments)

of 876 m including Rupture Overpressure at

Typical Construction Occupied Bldg 1 of

31.1 psi. 1 psi Blast Overpresssure

exceeds Distance to the Fence Line of 100

m. Consider adjustment for Off-Site Impacts

with the potential for Severity Level-5

< Back to Scenario Results

+

Expand All Collapse All

> Human Error ++ +> Possible IPLs

RAST is suggesting that the damage

distance is very significant such that

a Probability of Exposure enabling

condition would not be appropriate.






In addition to a high temperature interlock with an emergency cooling water supply, one

of the most cost effective Protective Layers would likely be a second Pressure Relief

Device. However, a Relief Device may not be effective for the Diglyme decomposition

which would not be predicted in RAST and need to be confirmed by kinetic modeling.

BPCS Control or

Human Response

to Alarm

BPCS Control or

Human Response

to Alarm

SIS Function A SIS Function BPressure Relief Device SRPS 1 SRPS 2 SRPS 3

SIS - SIL 1

Two Independent PRDs

on Separate Nozzles

with Independence

Audit

1 4

Notes / Comments Issues to Resolve

High temperature activates

emergency cooling water

addition

Two separate and

independent pressure

relief devices set at a

releatively low pressure

confirmed by kinetic

modeling

Not Allowed

+ + + +






Risk Analysis and Incident Investigation often use similar methods to better understand

the scenario. Risk Analysis “anticipates” what could go wrong and what the potential

consequences may be. For Incident Investigation, the Incident Outcome and

Consequences are known in addition to the actual weather conditions and wind direction.

For the MCMT Reactor, RAST did suggest Uncontrolled Reaction as one of many

scenarios to consider. RAST also recognized that a Physical Explosion could be a

feasible Incident Outcome for the scenario. RAST was is good agreement with the CSB

estimate of damage and potential loss of life.

RAST can not predict reaction hazards if the data is not entered (decomposition).

THE USER MUST KNOW THE CHEMISTRY THEY ARE DEALING WITH.



Questions?


ccps an aiche technology alliance · 2020-03-20 · ccps center for chemical process safety an...

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