Cooling Tower ExplosionVisakhapatnam, India, 2013

Richa Sarkar

MS, Safety Engineering

Mary Kay O’Connor Process Safety Center

Artie McFerrin Department of Chemical Engineering

Texas A&M University

Steering Committee Meeting January 19th, 2017

Case Study

1

About Myself

• Hometown - Bihar, India

• Bachelors in Chemical Engineering (2005-2009)

National Institute of Technology, Trichy, India

• Process Engineer (2009-2015)

Hindustan Petroleum Corp. Ltd., Visakh Refinery, India

• MS Safety Engineering

Texas A&M University, College Station, USA

2

Outline

• Background

• Incident Description

• Consequences

• Analysis

• Lessons Learned

• Acknowledgement

3

Hindustan Petroleum Corporation Ltd. (HPCL)

•Indian state-owned oil & natural gas company, HQ in Mumbai, India.

• A public sector undertaking of the Govt. of India.

• Formed in 1974 by combining Esso and Lube India

•Two refineries – Mumbai and Visakhapatnam

4

Visakh Refinery• Commissioned as Caltex

Oil Refining India in 1957

• Taken over by government of India and merged with HPCL in 1978

• Visakh Refinery Expansion Projects –

VREPI – 4.5 MMTPA (1985)

VREPII – 7.5 MMTPA (1999)

Effective April 2010 – 8.3 MMTPA

5

Cooling Towers

• The refinery has 3 cooling towers

• Each added during expansion projects

VREPI

VREPII

VRCFP (Visakh Refinery Clean Fuels Project)

• Each provided with 4 cells and induced draft operating mechanism

• 5th cell was to be added to VRCFP cooling tower – to meet the requirements of Diesel Hydrotreater (DHT) Block

6

Sequence of events

VRCFP cooling tower – all cells collapse

Interconnection schemes – to sustain operations

New (5th) cell construction complete

Explosion during commissioning of new cell

7

Cooling tower operation

• Heat rejection to atmosphere

• Inexpensive means for handling low grade heat

• Fills are provided to increase contact area

http://www.svlele.com/piping/cooling_water.htm

8

Cooling tower operation

Fig 2 - Closed loop cooling water system [1]

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Incident Description

• VRCFP cooling tower commissioned in 2009-10

• All 4 cells collapsed within 2-3 years

• Internal investigation concluded – design issues, improper load distribution

• Design modifications carried out for flow redistribution to individual cells

• Re-construction work of collapsed cells – handled by Maintenance department

• Construction of new 5th cell – handled by Projects department

10

Incident Description

• To sustain operations and reduce flaring –

interconnection provided between old and VRCFP cooling tower return and supply headers

Make-up water quantity was increased

• Decided to take the 5th cell in service – while construction continued on remaining 4 cells

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Incident Description

Fig 3- sketch of cooling water lines to VRCFP cooling tower [5]

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Incident Description

• Construction work for 5th cell completed

• Jump over to take 5th cell online, executed in field on 23rd

August

• Decided to go ahead with commissioning at shift change-over time

• Explosion occurred at 1646 hrs on 23rd August 2013, when the isolation valve was opened to commission 5th cell

13

Incident Scene: Before

http://www.process-cooling.com/ext/resources/issues/April2015/Emerson/PC0415_Slideshow_Emerson_1.jpg?1435691229

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Incident Scene: Damage

http://www.thehindu.com/news/national/andhra-pradesh/one-dead-39-injured-in-vizag-refinery-blast/article5052564.ece

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Consequences:

• 28 fatalities – 1 employee + 27 contract workers

• Several others with burn injuries

• Further delay in commissioning and limited production

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Analysis: What went wrong

• Accumulation of hydrocarbon in the jump-over line

• No sample analysis of line content prior to commissioning

• Hot-jobs continued in adjacent cells at the time of commissioning

• Failure to check HC leakage in to cooling water in connected process units

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Analysis: Management decisions

• Failure to prevent commissioning activities, with plenty of jobs unfinished

HC/H2S detectors were not installed

Fan cabling was incomplete

Improper co-ordination between Operations, Maintenance and Project departments

• Decision to go ahead with commissioning at shift change-over time

• Failure to implement procedures – PSSR, pre-com audit

• Commissioning procedure not followed – 16 jobs were going on, with 9 permits for hot job

• Standard operating procedure was not available

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Analysis: Technical deficiencies

• Jump-over connection was at elevated location –resulting in accumulation of light hydrocarbons

• Significant distance between the isolation valve and the location where tie-in was made

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Lessons Learned: Procedural

• Hot works and commissioning activity should not be allowed simultaneously

• PSSR should be done prior to commissioning new facility

• Check points of pre-commissioning audits and internal audits should be completed

• Minimum number of operating crew and nobody should be present at work site

• Provision of HC and other detectors as applicable should be ensured

• Hazard Identification and Risk Assessment should be ensured prior to commissioning of any new system

• Lack of operating procedure

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Lessons Learned: Technical

• Always check and follow industrial standards

• Wherever possible avoid creation of dead-zones

• Provide high point vents, low point drains and appropriate sample points

• Ensure flow pattern within the line when providing take-off

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Acknowledgement:

• Dr. M. Sam Mannan

• Dr. Guanlan Liu

• Pritishma Lakhe

• Ankita Taneja

• Valerie Green

• Alanna Scheinerman

• Members of MKOPSC

• Members of SC

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References:

1. Lj. Matijasevic, A. V., and I. Dejanovic. (2014). Analysis of Cooling water systems in a Petroleum Refinery. Chemical and Biochemical Engineering Quaterly, 8.

2. Analysis of Incidents reported to PNGRB from July, 2013 to December, 2014. (2015). Retrieved 1/10/2017, from Petroleum & Natural Gas Regulatory Board http://pngrb.gov.in/Notices.html

3. http://www.oisd.nic.in/

4. http://oisd.nic.in/PDF/OISDCaseStudies/OISDCaseStudyCoolingTowerFire.pdf?WhatNewId=20&button=Edit

5. https://www.icheme.org/shop/lpb/2015/issue%20245/explosion%20in%20a%20cooling%20tower.aspx

6. http://www.hindustanpetroleum.com/documents/pdf/AnnualReport2013-14.pdf

7. http://www.thehindu.com/news/national/andhra-pradesh/one-dead-39-injured-in-vizag-refinery-blast/article5052564.ece

8. http://www.thehindubusinessline.com/companies/death-toll-in-hpcl-accident-rises-to-28/article5159682.ece

9. http://indiatoday.intoday.in/story/death-toll-in-vizag-hpcl-refinery-fire-rises/1/301164.html

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Questions/ Comments

Thank you for your attention!

richasarkar.287@tamu.edu