LPG - Environment Clearance

Bharat Petroleum Corporation Ltd.,

LPG Bottling Plant, Cherlapalli, Hyderabad, Andhra Pradesh

PROPOSED INSTALLATION OF

ADDITIONAL MOUNDED STORAGE

UNITS FOR LIQUIFIED PETROLEUM

GAS (LPG)

RISK ANALYSIS REPORT

July 2015

Submitted by:

RiskChem

Engineering

#4 First Street

VGP Golden Beach South Part III

Off East Coast Read

Chennai 600119

TN, INDIA

Tel: (+91 44) 24530699

Mob: (+91) 98401 44908

RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Table of Contents

CHAPTER 1

1.1

1.2

1.2.1

1.3

1.4

1.5

CHAPTER 2

PROJECT DESCRIPTION

P

REAMBLE

D

ESCRIPTION OF PROPOSED

M

OUNDED

S

TORAGE

S

YSTEM FOR

LPG

Safety Features on the Mounded Storage vessel

D

ETAILS OF THE

L

OCATION

& E

NVIRONS

N

EED FOR

R

ISK

A

NALYSIS

S

COPE OF

W

ORK

PRELIMINARY HAZARD IDENTIFICATION FOR MOUNDED

BULLET

2.1

2.2

2.3

2.4

CHAPTER 3

3.1

3.2

3.3

3.4

3.5

3.6

3.6.1

3.6.2

3.7

3.8

3.9

P

REAMBLE

H

AZARD

C

LASSIFICATION BASED ON

NFPA

AND

I

NHERENT

H

AZARDS OF

LPG

H

AZARD

P

OTENTIAL BASED ON

F

IRE

& E

XPLOSION

I

NDEX

I

DENTIFICATION OF

H

AZARDS

RISK EVALUATION FOR MOUNDED STORAGE

P

REAMBLE

C

REDIBLE

A

CCIDENT

S

CENARIOS FROM PROBABLE LEAK OF

LPG

C

ONSEQUENCE

A

NALYSIS

P

ROTECTION MEASURES ON THE MOUNDED BULLET

W

ORST

D

AMAGE

C

ONTOUR

P

LOTS

P

ROBABILITY OF

O

CCURRENCE

Meteorological Data

Probability of Ignition

P

ROBABILITY

E

STIMATION

A

CCEPTANCE

C

RITERIA

A

DDITIONAL

R

ISK FROM INTRODUCTION OF

N

EW

M

OUNDED STORAGE UNITS

CHAPTER 4

4.1

4.2

4.3

4.4

4.5

4.6

4.7

APPENDICES

ANNEXURE 1

A.1

A.2

A.3

FINDINGS & RECOMMENDATIONS

P

REAMBLE

S

UMMARY OF

R

ISK FINDINGS

R

EVIEW OF

P

ROPOSED

S

AFETY

S

YSTEM AND

R

ISK

R

EDUCTION

M

EASURES

P

ROPOSED

R

ISK

C

ONTROL

M

EASURES

P

ROPOSED

R

ISK

M

ITIGATION

M

EASURES

R

ECOMMENDATIONS FOR CONTINUAL IMPROVEMENT

C

ONCLUSION

23

A

PPENDIX

1.1

A

PPENDIX

1.2

A

PPENDIX

2.2

A

PPENDIX

2.3

A

PPENDIX

3.1

A

PPENDIX

3.2

A

PPENDIX

3.3

A

PPENDIX

3.4

D

ETAILS OF THE

E

XISTING

LPG

BOTTLING PLANT FACILITIES

E

QUIPMENT

S

PECIFICATION

S

HEET

S

PECIFICATIONS OF

LPG

M

ATERIAL

S

AFETY

D

ATASHEET

F

IRE

, E

XPLOSION AND

T

OXICITY

I

NDEX

W

ORKSHEET

F

IRE

D

AMAGE

M

ODELING

& C

RITERIA EMPLOYED

R

ESULTS OF

C

ONSEQUENCE

A

NALYSIS

L

OCATION OF

S

OURCES OF

I

GNITION WITHIN THE

BPCL I

NSTALLATION

A

PPENDIX

3.5

P

OPULATION

D

ISTRIBUTION AT THE SITE

A

PPENDIX

4.1

F

IRE

D

ETECTION

/ P

ROTECTION

S

YSTEM

HAZARD & OPERABILITY (HAZOP) STUDY

P

REAMBLE

C

ONDUCT OF THE

HAZOP

SESSIONS

N

ODES CONSIDERED FOR THE

HAZOP S

TUDY

43

43

43

43

31

32

33

36

24

26

28

29

37

38

6

6

6

7

7

9

12

15

15

15

9

9

10

11

16

17

17

18

18

18

18

19

20

21

22

1

1

1

1

2

2

3

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A.4

A.5

A.6

A.7

RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

R

EFERENCE

D

OCUMENTS

P

ARAMETERS ADOPTED FOR THE STUDY

R

ESULTS OF THE

HAZOP

STUDY

HAZOP W

ORKSHEETS

44

44

46

50

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

OISD

PHA

PI

PLT

PSV ppm

QRA

ROV

MCP

MCAC

MF

MHISC

MSDS

MT

NFPA

NRV

SOP

SPH

SRV

TI

TLF

TSV

TT

TWD

UFL

LIST OF ABBREVIATIONS

A/G Above Ground

ATG b.p

Automatic Tank Gauging

Boiling Point

BLEVE

BPCL

CCPS

CPQRA

Boiling Liquid Expanding Vapor Explosion

Bharat Petroleum Corporation Limited

Center For Chemical Process Safety

Chemical Process Quantitative Risk Assessment

DCP

EFCV

ESD

F&EI

FLP

GAIL

GPH

HAC

HAZOP

LFL

LPG

Dry Chemical Powder

Excess Flow Check Valve

Emergency Shut Down

Fire & Explosion Index

Flameproof

Gas Authority of India Ltd

General Process Hazard

Hazardous Area Classification

Hazard and Operability Study

Lower Flammable Limits

Liquefied Petroleum Gas

Manual Call Point

Maximum Credible Accident & Consequence

Material Factor

Manufacture, Storage & Import Of Hazardous Chemicals Rules

Material Safety Data Sheet

Metric Tonnes

National Fire Protection Agency

Non Return Valve

Oil Industry Safety Directorate

Preliminary Hazard Analysis

Pressure Indicator

Pipe Line Transfer

Pressure Safety Valve parts per million

Quantitative Risk Assessment

Remote Operated Valve

Standard Operating Procedure

Special Process Hazard

Safety Relief Valve

Temperature Indicator

Tank Lorry Filling

Temperature Safety Valve

Tank Truck

Tank Wagon Decantation

Upper Flammable Limits

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Chapter 1 Project Description

1.1 Preamble

Bharat Petroleum Corporation Limited (BPCL) operates an LPG bottling plant within its site in Cherlapalli, Ranga Reddy District, Andhra Pradesh. The plant, commissioned in 1999, has been storing LPG onsite in three above ground storage bullets and three mounded storage vessels. From these storage units, LPG is drawn for filling cylinders, which, after due testing and sealing are dispatched to various destinations. The company now proposes to increase the existing storage capacity.

The increase in storage will be effected by introducing two additional mounded bullets of 600 MT capacity each. The proposed introduction will in no way alter the current activities of the LPG plant. There will be no change in the frequency of bulk road lorry tank unloading or the cylinder filling rate at the carousel unit. A description of the existing plant is given in Appendix 1.1.

1.2 Description of proposed Mounded Storage System for LPG

The mounded storage vessels will be designed to store 600 MT Liquefied

Petroleum Gas at 14.5 Kg/cm

2 g (1.42 Mpa) vapour pressure of LPG at top of the vessel (as per IS: 4576 or IS: 14861) at 55 o

C. The proposed additional storage consists of two units of mounded bullet, 48.5 m long and having a diameter of 6 m.

The vessel shall have a shell thickness of 20-mm. The storage vessel is to be provided with 150-mm liquid and 150-mm vapor lines. The vessel is also to be provided with two safety relief valves (SRV) on top of vents raised to 3 m from the top of the mounded storage vessel, set at a pressure of 13.6 and 14.1 kg/cm

2

.

Cathodic protection is envisaged for each mounded storage vessel to guard against corrosion.

The mounded storage vessel is to be mounded over to a height of 2.5-m from the ground level. Terram geotextile sheets of 1000 microns will be laid for protection of the bullets from water seepage. A retaining wall is proposed to be built in front of the manifold and mound on the other side. The entire mound is to be covered on all sides with earth at a slope of 1:1.5 with a cover of 1-m on the top. The diagram of

LPG mounded bullet is shown in Fig 1.1. The equipment specifications are given in

Appendix 1.2

1.2.1 Safety Features on the Mounded Storage vessel

It is encouraging to note that BPCL has opted for the use of mounded vessels for

LPG storage (designed as per OISD 150). The mounded storage vessel has a number of inherent safe design features. The relevant features are highlighted below:

(i) Presence of ROV on the Inlet/ Outlet pipelines

The presence of fire-safe Remote Operated Valves (ROV) on the pipeline connected to the mounded storage vessel ensures that transfer operation from the bulk storage can be stopped from a remote location.

During non-operation hours the ROV will be kept in a closed position, eliminating any chance of product transfer from the vessel to the outside pipelines.

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

(ii) Barriers against external fire/ explosion

The mounded storage vessel is to be laid on a compacted sand bed with no raised support. This design protects the storage vessel from any source of fire impinging on it from any direction and virtually eliminates the possibility of failure of vessel and occurrence of fireball (BLEVE) scenario.

The retaining wall of reinforced concrete in front of the vessel protects it from effects of overpressure from blast waves and explosion.

1.3 Details of the Location & Environs

The proposed additional mounded bullet is to be located within its own dyked area adjacent to the existing storage units. The boundary wall of the site runs along the western side of the proposed location, as shown in Fig 1.2.

The operational activities for normal operations as well as emergency services for the mounded bullet will be integrated within the existing plant management system.

1.4 Need for Risk Analysis

Any industrial activity involving increase in onsite storage of hazardous chemicals named or classified in the various schedules1 under the Environment (Protection)

Act, 1986 attracts compliance with the rules formulated under this Act.

The quantity of LPG involved in the proposed storage exceeds the threshold quantities mentioned in the Schedules and the product falls under the Highly

Flammable and Flammable liquids categories

2 defined in these rules.

An inventory of onsite storage was made and is given in Table 1.1

Units

Table 1.1

Existing units

LPG bullets (A/G)

LPG mounded storage vessels

LPG tank lorry bay

Filled Cylinder Shed

Summary of Units and their Quantities

Max. Qty./ unit

Total no of units

Maximum Quantities

Stored at site (MT)

150 MT

425 MT

8-18 MT

14.2 kg

3

3

6

~ 4700

Current Maximum Capacity

450

1275

108

67

1900

Proposed additional units

LPG mounded storage vessel 600 MT 2 1200

1

The Manufacture, Storage & Import of Hazardous Chemicals (Amendment) Rules, 2000 of the

Environment (Protection) Act, 1986

2

Manufacture, Storage & Import of Hazardous Chemicals (Amendment) Rules, 2000,

Schedule 3 (Part II)

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

The rules applicable require detailed risk assessment studies to be conducted. The management has entrusted the risk analysis studies to be carried out by consultants from RiskChem Engineering (RCE), Chennai.

BPCL has received approval to operate its existing storage vessels and associated facilities.

The risk, if any, arising from the proposed additional mounded bullet is discussed in the report. Findings of the Risk Analysis studies will assist the statutory/ regulatory authorities in approving the proposed addition of LPG mounded bullets of BPCL at

Cherlapalli.

1.5 Scope of Work

The current risk analysis studies are confined to the proposed mounded storage units and associated connections. The associated activities and pipe sections analyzed here are restricted to the connections/ tie-in lines to the existing vapor and liquid headers and cover the following a) Receipt via pipeline/ tank wagons/ tank lorries and Loading of the bullet b) Storage of LPG in the additional storage units

Other units and associated activities involving the road lorry tanks, pump/ compressor house, filling station and filled cylinder shed remain unchanged from the existing practices and are therefore not included in the present analysis.

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Chapter 2 Preliminary Hazard Identification for Mounded Bullet

2.1 Preamble

LPG unloading, storage and distribution are inherently hazardous operations due to the flammable/ explosive characteristics of LPG. The mere existence of hazards, however, does not automatically imply the existence of risk for the mounded bullet.

Screening & ranking methodologies and risk assessment techniques have to be employed to evaluate risk of the mounded bullet. Risk Evaluation was conducted in the following stages:

1. Preliminary screening of hazards

2. Consequence Assessment

3. Probability estimation

4. Risk contour Mapping

This chapter sums up the risk posed by the proposed operation and its effect within and outside the plant site.

2.2 Hazard Classification based on NFPA and Inherent Hazards of LPG

The National Fire Protection Agency, US (NFPA) has classified the hazards from

LPG (considered as a mixture of commercial butane and commercial propane having both saturated and unsaturated hydrocarbons) in the following scale

NH (Health)

NF (Flammability )

NR (Reactivity)

Table 2.1 NFPA rating *

1

4

0

*NFPA classification for Health, Flammability & Reactivity of a chemical on a scale of 0 – 4 least to worst

Since LPG is inherently dangerous because of fire, explosion and has maximum rating hazards it calls for special attention on the manner in which it is stored, transported or used. Table 2.2 summarizes the physical properties of LPG

Table 2.2

Boiling Point (C)

Flash Point (C)

Auto Ignition (C)

Lower Flammable Limits (LFL)

Upper Flammable Limits (UFL)

Physical Properties of LPG

-40

-104.44

466

2%

10%

There are a number of other properties that characterize the hazard potential of a petroleum product. As the flash point is low, LPG can form large quantities of flammable vapour cloud on release into the atmosphere. However it requires contact with a strong ignition source before ignition can occur.

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

2.3 Hazard Potential based on Fire & Explosion Index

The next stage of hazard identification involves the estimation of Fire & Explosion

Indices for the units in the facility to give the relative severity of the units from the fire angle.

These are evaluated from the knowledge of the material hazard factor, General

(GPH) and Special Process Hazard (SPH) factors. Material Factor (MF) is the measure of the energy potential of a particular chemical or its mixture with other chemicals. GPH and SPH are evaluated by taking into account the exotherm or endotherm of a reaction, material handling and transfer hazards, accessibility, severity of process conditions and possibilities, dust and other explosions, inventory level of flammable material, etc.

The F&EI value is then calculated as the product of MF, GPH and SPH. Detailed fire and explosion indexing was carried out for the proposed storage units of the plant to give the relative degree of severity of the units using the criteria given in

Table 2.3.

Table 2.3 Criteria for Degree of Hazard for Fire and Explosion Index

Index range Degree of Hazard

1-60

61- 96

97-127

128-158

>159

Light

Moderate

Intermediate

Heavy

Severe

The worksheet for the F&EI estimated for the LPG mounded storage vessel is given in Appendix 2.1

2.3.1 Analysis of F&EI Results

The result of the onsite storage is given in Table 2.4. From the results of the F&EI studies, it can be observed that the storage unit has F&EI values of 103 and falls under the intermediate class of fire and explosion hazard.

Table 2.4

Units

F&EI Calculations -- Summary Table for Hazardous Units

Max.

Qty./ unit

Material

Factor

MF

Fire & Explosion

Index

F&EI

Degree of

Hazard

LPG mounded storage vessel 600 MT 21 103

Intermediate

2.4 Identification of Hazards

The HAZOP study has identified several causes that may result in the release of pressurized LPG into the atmosphere. These are summarized below under two broad heads, namely, those that can occur on the bullet, and those that occur on the pipelines. Identification of the causes can lead to appropriate actions to be devised to eliminate or mitigate them and thereby ensure the safety of the operation.

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Unit

Bullet

(Mounded storage vessel)

Pipelines

Table 2.5

Vapor & Liquid

Causes

Summary of significant elements of the HAZOP study

Hazard Consequences

 Overfilling

 Pressure increase in bullet

 Instrumentation failure

 Operator error

 External fire

 Corrosion

 Rupture of hose

 Gasket Failure

 Leak at flanges

 Wrong line-up

 Non adherence to

SOP for sampling

Release of pressurized LPG into atmosphere

Release of pressurized LPG into atmosphere

Jet fire/ Flash fire

Flashfire/ Dispersion

Failures of the pipeline/ flanges or at instrument connections on vessel or line may be the initiating cause for loss of containment leading to possible fire, or dispersion.

The potential releases and consequences are quantified in the following chapter.

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Chapter 3 Risk Evaluation for Mounded Storage

3.1 Preamble

Risk is a function of two parameters, the severity of the consequences and the probability of occurrence of a particular hazard. Both probability and consequence in turn depend upon several factors, of which some are qualitative

– human factors, the timing of the occurrence and the attitude of the people. Therefore, a range of methods has to be used to estimate the risk of a situation.

The various scenarios identified through the preliminary hazard analysis and the

HAZOP studies were quantified using modeling techniques. This was followed by probability assessment. The final risk evaluation for all the scenarios pertaining to the mounded bullets in the form of risk numbers provide a relative measure of the risk associated with the operation.

The proposed additional storage has been assessed for its potential to initiate and propagate an unintentional event or sequence of events that can lead to an accident or emergency. The study has covered the following sections. a) Mounded storage vessels during non- pumping hours b) Mounded storage during unloading and filling operation

Credible accident scenarios (CAS) were initially constructed followed by quantification using Cause-Consequence models for the identified scenarios. The assessment was based on well-recognized and internationally accepted screening methodologies.

3.2 Credible Accident Scenarios from probable leak of LPG

A number of credible accident scenarios were examined involving release of LPG from the proposed mounded storage units. Scenarios considered here include pipeline leak of vapor or spill of liquid from the inlet/ outlet lines. The spilled amount will evaporate and form a continuous dispersion. Such leaks/ spills will lead to the formation of flammable vapor, which if ignited, can have severe effects. Scenarios where spill of LPG can form vapor clouds were closely examined.

The scenarios identified for the LPG unloading, storage and distribution operations are shown in Table 3.1. Two major types of consequences may be expected under these circumstances, viz.

1) Jet fires: If LPG leaks, (either from a liquid or vapour line) and an immediate source of ignition is available then jet fire is assumed to occur

2) Flash fires: In the absence of immediate ignition, it is assumed that LPG release will lead to a continuous dispersion of LPG vapour. This vapour cloud would then accumulate to a flammable concentration. In the event of ignition a vapour cloud can result in burn as a flash fire (a short duration, high intensity fire).

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

3.3 Consequence Analysis

The extent of the consequences of an accident depends on the type and quantity of the LPG stored and handled, mode of containment, and external factors like location, density of population in the surrounding area, etc. In many cases realization of hazard and its potential also depend on prevailing meteorological conditions and availability of ignition source.

Detailed consequence analysis was carried out for each of the identified scenarios.

Table 3.1 Summary of Consequence Scenarios for LPG mounded storage vessel

Scenario Discharge

Phase

Discharge rate

(kg/s)

Pipe size mm

Probable

Consequence

1a. 100% release from Bottom

(liquid) pipe section away from vessel

1b. 20% release from liquid pipe section away from vessel

Two-phase 11.7

Two-phase 2.34

150

150

Flash

Jetfire

Flash

Jetfire fire/ fire/

Vapor 17.7 150 Jetfire 2a. Top Vapor Line 100% release from vapor line

2b. 20% release from vapor line

3. Safety Relief Valve 100% release from Stack 10-m above ground level

4. 100% release from the liquid line from road lorry tank to bullet

Vapor

Vapor

Liquid

3.54

4.16

(SRV rate)

6.6

(Filling rate)

150

150

150

Jetfire

Jetfire

Spill/ Jetfire

At the rates of release calculated in these scenarios, the quantities expected to be released are too low for the development of Vapor Cloud Explosions, hence this consequence has been eliminated.

Detailed consequence analyses have been carried out for cases of Jetfires and flashfires. The fire damage criteria followed in the analysis are given in Appendix

2.2. The events depicting the worst-case scenarios are summarized in the following tables.

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Event

Ref.

No.

1a.

2a

Scenario

100% release from

Bottom liquid pipe

(outside mounded area) away from vessel

100% release from Top vapor line

Table 3.2

Discharge rate kg/s

Maximum Damage from Jetfires

3

Thermal radiation inside jet

Length Width Damage distances (m)

37.5 kW/m 2

12.5 kW/m 2

4 kW/m 2 kW/m

2 m

m

DW

4

CW

5

DW CW DW CW

11.7 92 39 3 41 5.5 44 14 48 27

17.7 77 47 4 49 5.6 52 14.5 56.8 29.3

Event

Ref. No.

2a

1a

Table 3.3

Scenario

Top Vapor Line 100% release from vapor line

6

100% release from

(

Bottom liquid

) pipe section (Outside the mounded area)

Maximum Damage from Flashfire

Release rate

LFL distance

(DW) kg/s

17.7

m

28

11.7 11

Cloud radius

(CW)) m

18

10

3.4 Protection measures on the mounded bullet

The water spray and deluge system provide the cooling barrier to the units against direct or indirect heat radiation. It may be noted that both liquid and vapor lines are equipped with remote operated valves (ROVs) on the pipelines to close product supply.

Other protection/ mitigation schemes include deluge valves, single & double hydrant points for cooling units, gas detectors, safe pipe design, and reinforced concrete wall in front of the storage unit. The efficiency of these safety devices is assessed in the probability analysis.

The details of the analysis have been given in Appendix 3.3.

3

Appendix 3.5 Table 3.5.1 for Damage criteria from Thermal Radiation

4

DW = downwind

5

CW = crosswind

6

(Rupture = 100%, leak 20 % of pipe area) Source strength for dispersion -- 52 % of discharge rate

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

3.5 Worst Damage Contour Plots

The worst damage contours were plotted on the site plan. These contours are shown in Fig. 3.1 & 3.2

The damage contours presented here refer to the following scenarios

1) Thermal radiation due to Jet fire (Fig 3.1)

2) Thermal radiation zones from Flashfire (Fig 3.2)

The damage zones are restricted within the plant boundary. It can also be noted that the movement of vapor cloud in event of leak will disperse in the most probable wind direction (west to east). The direction of the jet fire has been plotted along the orientation of the pipes connected to the top of the bullets.

LEGEND for Figures

Code for Jet Fire THERMAL RADIATION IN KW/M2

Maximum radiation within the jet

37.5

12.5

4

CODE For Flash Fire

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

3.6 Probability of Occurrence

The factors affecting the probability of occurrence of any of these unwanted events are as follows a) Wind direction b) Terrain & Slope c) Ignition sources in the de-licensed area d) Possibility of leak or its effects reaching population

These factors were examined by plotting the damage contours of various leak scenarios on the site plan of BPCL.

3.6.1 Meteorological Data

7

The climate is temperate with recorded temperature ranging from a maximum of

41

C and minimum temperatures of 17C. Average relative humidity ranges from

26 to 89%. Wind velocity ranges from 20.2 to 90 kmph. The wind direction is predominantly west to east.

3.6.2 Probability of Ignition

The hazard of fire/ explosion from loss of containment of LPG will be realized only in the presence of air (oxygen) and an ignition source. The circumstances leading to explosive situations, such as sufficient quantity of LPG, confined spaces, etc., have been shown to be improbable in the consequence calculations; hence, vapor cloud explosions have been eliminated.

As the availability of an ignition source is essential towards the realization of any unwanted fire the site was closely examined. Possible ignition sources and the safeguards in place were identified and the details are given in the Appendix 3.4

The analysis of the plant site has shown that there are over ten possible ignition sources in place. This indicates that in the event of leak of LPG from storage units in the proximity of ignition sources, the hazard of fire may be realized. Further detailed analysis using probability analysis is hence justified for the proposed locations of the additional storage units.

A typical case will occur under the following sequence of events.

7

Ref: BPCL Cherlapalli, Safety Audit Report (2007-08)

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Fig 3.3 Event Tree for Continuous Release of LPG

Remote

Operated

Valve (ROV)

Ignition

IMMEDIATE

Jet Fire

Flash fire

Pipe failure leading to

CONTINUOUS

RELEASE of LPG

DELAYED

SAFE

Dispersion

YES (Fails)

NO (operates

as intended)

SAFE

(release contained)

A typical probability value of an occurrence of the consequences is calculated using the sequence given above

3.7 Probability Estimation

Based on the above approach, the probabilities of occurrence of jet fire and flashfire from LPG release from the 150mm liquid and vapor lines are examined and given below

Table 3.4

Description

Probability of Occurrence of Jet Fire on immediate ignition of release

Frequency of occurrence/ yr

Probability of leak in 150-mm pipeline

Probability of failure of ROV

0.000003

0.1

Probability of immediate ignition 0.08

The probability of the occurrence of jet fire is 2.4 x 10

-8

per year, which is extremely low.

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Table 3.5

Description

Probability of Occurrence of Flashfire on delayed ignition of release

Frequency of occurrence/yr

Probability of leak in 150-mm pipeline

Probability of failure of ROV

Probability of delayed ignition

0.000003

0.1

0.5 (9.2 x 10

-1

)

The probability of the occurrence of flashfire is 1.38 x 10

-7

per year, which is extremely low.

3.8 Acceptance Criteria

To further assess the risk posed by the installation, a comparison may be made with risk criteria for levels of risk that is considered tolerable for similar industries. A selection based on the type of industry was made among the criteria commonly adopted and is given below.

Table 3.6

Application

Risk Criteria adopted for the installation

8

Maximum Tolerable Risk

(per year)

Negligible Risk

(per year)

Existing Hazardous Industry 1.0E-4 1.0E-6

It can be seen that against these criteria, the risk arising from the introduction of the additional mounded storage units is negligible.

3.9 Additional Risk from introduction of New Mounded storage units

The risk to the existing plant and its operation due to the installation of the additional mounded storage bullets ranges between 10

-7

to10

-8

/yr. The location of the additional mounded storage units at the western side of the site ensures that the risk has minimum effect on other units and activities within the site.

As the additional storage does not envisage any change to the existing operations, it may be concluded that the contribution from these units to the existing risk will be minimal.

8

Extract from Hazard Identification & Risk Analysis

– Code of Practice IS 15656 : 2006; ANNEX E

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

CHAPTER 4 Findings & Recommendations

4.1 Preamble

The risk of fires and explosions arising out accidental release of LPG from pipeline connections to the mounded storage vessel were investigated in the previous chapters. The locations of leak include liquid inlet pipeline and vapor lines on the top of the bullet.

The results of the risk assessment and recommendations based on these results are given in this chapter

4.2 Summary of Risk findings

The main findings arising from the risk evaluated for proposed LPG mounded bullet are summarized below

1. The damage zones from the fires show the region corresponding to the high radiation zones are contained within the plant and in the immediate vicinity of the mounded bullet.

2. The design of mounded bullet ensures protection against effects of an external fire by the process of mounding. The sand cover provides near compete isolation of the vessel against any source of external source of fire and heat radiation

3. The proposed location of mounded bullets in the site layout was examined to study the effects of radiation effects on the surrounding area. a. It can be seen that the thermal radiation effects of jet fire (Fig 3.1) from the

LPG mounded bullet will be felt at the LPG compressor shed. These areas however do not have any permanent personnel stationed. b. Personnel working in areas such as unloading bay & filling shed fall outside these heat radiation zones.

4.3 Review of Proposed Safety System and Risk Reduction Measures

Two locations of leak were investigated on the liquid line connected to the mounded vessel. At the first location, leak was assumed before the ROV; in the second case leak was assumed after the ROV

If the leak in the line occurs after the ROV, ROV on liquid/ vapor line will cut the source of fuel, which is the correct response in preventing an occurrence of a jet fire.

However these measures will be ineffective if the leak occurs before the ROV. In such cases, mitigation will rely on the water hydrant system. It must be ensured that fire-fighting pump system is maintained to take care of any eventuality in case of such leaks.

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Safety measures must be proportional to the additional risk due to the introduction of the mounded bullets. A Safety Review of the existing plant was carried out to check if the requirements of the additional measures for the storage units

(summarized in Appendix 4.1) were available. Based on this review and the nature of risk assessed, the following additional measures have been proposed.

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

4.4 Proposed Risk Control Measures

A number of events have to precede the occurrence of jetfire or flashfire as illustrated in the previous chapter. Based on the sequence of events (Fig 3.3), the probability of occurrence is shown to be low.

This probability value will be further reduced if the proposed mitigation measures such as gas detectors, water spray systems, automatic fire-fighting systems and deluge valve systems are also taken into consideration. The proposed measures are summarized in the table below.

Table 4.1 Proposed Mitigation Measures

Scenario type

Fire

Dispersion

(No ignition)

Location 1

(at Ground Level)

1. Water spray system located near the ROV/ valves actuated by quartzoid bulb (24 lpm/ m

2

)

2. Water jets from single and double water hydrant system located on the fire water ring main header surrounding the mounded bullet

3. ROV

9

to cut off supply.

1. Gas detectors and alarms

2. ROV

1

to cut off supply

3. Water jets from single and double water hydrant system located on the fire water ring main header surrounding the mounded bullet

Location 2

(at the top of the bullet)

1. Water spray system actuated by quartzoid bulb located on the top of the bullet at the nozzle dome and the manholes.

2. Medium velocity Water jets from single and double water hydrant system located on the fire water ring main header surrounding the mounded bullet

1. Vented at 10m height from the ground level

10

.

Several other factors inherent to site selection and selection of equipment will further contribute to the unlikelihood of the possibility of fire or explosion

1) Rapid drop in flammable concentration

Under normal wind conditions LPG concentrations will drop below the flammable levels within 50-m

11

from the point of leak. The probability of the cloud reaching the ignition sources at flammable concentrations is low.

2) Protection of ignition sources in licensed area

The selection of equipment such as pump or compressor in the licensed area will be as per specifications for use in Hazardous Areas. This will reduce the possibility of ignition occurring even if the wind direction is towards the main operation

9

This will be effective only if the leak occurs downstream of the ROV

10

The cloud is likely to disperse rapidly to below LFL

11

As per dispersion calculation

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

4.5 Proposed Risk Mitigation Measures

It has been shown that the risk from the proposed LPG mounded bullet arises from leaks of pipeline joints. It is therefore important to address the reduction of the possibility of leaks of LPG thereby reducing the chance and occurrence of fire.

No.

1

2

3

The following additional measures are therefore recommended.

1) Location of hydrocarbon detectors. Introduction of gas detectors at strategic locations is essential for early detection of leak. The existing plant has over 26 units of gas detectors. For every new mounded bullet, six units of gas detectors would be required at critical pipe sections such as the liquid outflow pipeline between the pipe-vessel joints, inside the inspection tunnel, the ROV and the drain system. Gas detection system installed in the immediate vicinity will provide an early warning to prevent LPG accumulation in the trench/ duct.

2) Elimination of ignition sources. An area of radius ~40m from the bottom liquid line connection to the liquid header may be declared and maintained as ignitionfree zone. BPCL should ensure adequate precautions (good maintenance) as well as control of activities within this zone by means of Work Permit system.

3) Dispersal of vapor cloud/ mitigation of fire. Thermal radiation effects from flash fires, though of extremely short duration, can cause burn injuries. The existing network of fire and water hydrant system should be extended to the proposed mounded bullet. Vapor cloud dispersion is required to disperse leaks of LPG thereby preventing buildup of vapors within the plant. The water hydrant and water spray system can be used to disperse the vapor cloud.

4) Training to operators. The unloading/ loading operations when connected to the bullet will continue to be a source of hazard as pressurization can occur due to several reasons as identified in HAZOP report. There are over 20 operators within the operating areas during daytime. Effective training to operators in emergency measures such as detection and dispersing of LPG leaks will help reduce the probability of fire at the mounded bullet.

5) Inspection & Maintenance Frequency. It is essential that a suitable inspection and maintenance schedule be drawn up for the critical safety devices based on the criticality and past failures. The degree of reliability and safety of these instruments must be established through studies such as probability analysis. The existing schedule is given below. This should be modified and updated based on a study of similar equipment as these safeguards directly influence the occurrence of the hazard.

Table 4.2

Safety systems

Frequency of Maintenance for safety devices on the proposed mounded bullet

Rochester gauge (shows LPG bullet level in percentage) is provided on the top of the nozzle dome.

Frequency of Inspection/ routine checks

Daily

Servo level gauge (shows LPG bullet level in mm) is provided on the nozzle dome.

High level alarm is provided on the top of the bullet.

Daily

Annual

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

No.

4

5

6

7

8

9

10

Safety systems

Excess flow check valve is provided on the drain line next to

ROV. It is also provided on the pressure gauge which is located on the top of the bullet.

Frequency of Inspection/ routine checks

Annual

Two pressure safety valves are provided on the top of each bullet.

Biannual

Remote operated valve (ROV) is provided on the outlet liquid line from the bullet.

Tested daily

Two gas detectors are provided for each bullet. One is located at the bottom of the bullet (catalytic), near to ROV and other is located inside the inspection tunnel (infra red).

Quarterly

Water spray systems, activated by quartzoid bulb detectors & thermal safety fuses are provided for the exposed portion of nozzle dome, manhole and pipeline manifold.

Monthly

Deluge valves, single and double hydrant points are provided at the mounded storage vessel area.

Monthly

Cathodic protection is provided on the mounded bullet to avoid corrosion problem by creating uniform potential on the surface of bullet.

Biannual

4.6 Recommendations for continual improvement

BPCL may in addition to the above consider the following measures for the longterm safety of the installation

A) Incident Recording: The introduction of mounded storage vessel is of recent origin and not much literature on failures in this type of storage is available. A system of recording information regarding all incidents (leaks, fires, near misses, etc.) should be developed and maintained in the form of a database. This information could be shared with other LPG installations and a data bank developed to study the long-term effects of maintaining mounded storage vessels for LPG.

B) Emergency plan should be reviewed with necessary emphasis on the following aspects i. Emergency Shutdown system: This must be tested periodically as per the preventive maintenance schedule. ii. Gas Detection System: BPCL should ensure that the gas detection system is always in working condition by testing with suitable test gas. iii. Fire Drills: Mock emergency and fire drills should be conducted at defined intervals and documented. Communication systems are also to be checked during these mock drills

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

C) Safety Audit: Regular inspections and audits are necessary for safe operation of plant.

Safety audit of the plant covering various aspects is to be conducted as per OISD standards.

4.7 Conclusion

The risk of fires and explosion from the proposed additional mounded storage for

LPG is relatively low. The risk zones will be mainly confined within close proximity of the mounded bullets and will not have any effect on the personnel beyond this area. This is mainly due to the inherent safety of the design and construction of mounded type of vessel for storage of LPG.

The safety measures and other suggestions made in this report will further reduce the risks and ensure the long-term safe operation of the mounded bullets

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APPENDICES

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Appendix 1.1 Details of the Existing LPG bottling plant facilities

The existing LPG bottling plant is located in the industrial area about 20km from Hyderabad in Ranga

Reddy District of Andhra Pradesh. The nearest railway station is located at Cherlapalli and the site is well connected by rail and road. Well-equipped hospitals and health care facilities are available at Hyderabad

The plant comprises of on-site storage units for liquefied petroleum gas (LPG), a cylinder filling station and storage shed for cylinders, as well as facilities for receipt of LPG from pipeline (VSPL), train wagons and LPG tank lorries.

Existing Facilities

12

The LPG bottling plant comprises the following areas

1. Road lorry tank unloading shed

2. LPG storage bullets

3. Cylinder filling shed

4. Empty and filled cylinder storage shed

5. Evacuation facility

6. Valve change shed

7. LPG pump/ compressor house

8. Fire protection and fire protections system

PROPOSED MOUNDED LPG STORAGE FACILITIES

1. Horizontally placed two cylindrical vessels will be used for mounded storage

2. The design temperature is about - 27 o

C to + 55 o

C

3. The design pressure is about 14.5 Kg/cm

2 vessel (as per IS: 4576 or IS: 14861) at 55 o g (1.42 Mpa) vapour pressure of LPG at top of the

C

4. Other considerations:

 Internal Corrosion Allowance: 1.5 mm

 Radiography: Full

 Earthquake pressure: as per IS: 1893

5. Mounded vessels will be placed on a firm foundation and installed so as to prevent movement or floatation. The sub-soil water, rainwater or any other surface water will not be allowed to percolate in to the mound. The foundation will be constructed such that in the longitudinal direction of a vessel slope of about 1:1.5 will be maintained to facilitate draining of the vessel

6. The mound surface will be protected against erosion by rain or wind by providing a suitable protective cover of prefabricated stone, open concrete tiles, etc.,

7. The proposed mounded bullets receive LPG from three main sources,

 Pipeline Transfer from GAIL

 Train Wagons &

 Road Tank Lorries

8. The existing LPG liquid & vapour headers will be extended and tapped to the proposed mounded bullets

12

Details from Risk Analysis Report 1997

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

FITTINGS AND INSTRUMENTS ON A VESSEL

1. The fire safe Remote Operated Valve (ROV) will be provided on first flange on liquid line from the vessel from bottom as per the design considerations. There will not be any other flanges, or any other tapping up-to the ROV, structures.

2. The top of the vessel will be provided with nozzles for vapour outlet and re-circulation, which will also be provided with fire-safe ROVs.

3. Two nos. of manhole will be provided on top of the vessel.

4. Each vessel will have two Safety Relief Valves (SRV). The full flow capacity of each SRV on mounded vessel(s) will be minimum 30 % of the capacity required for an equivalent size of above ground vessel.

5. The discharge from safety valve will be vented vertically upwards to atmosphere without any intermediate valve on downstream side at an elevation of 3-meter from the top of the mound.

6. Each storage vessel will have two different types of level indicators and one independent high level switch. High level alarm will be set at not more than 85% level of the volumetric capacity of the vessel.

7. Audiovisual indication will be provided at local panel & control room.

8. Each vessel will also be provided with one pressure and temperature measuring instrument. The pressure gauge will be provided with two isolation valves and an excess flow check valve.

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Appendix 1.2 Equipment Specification Sheet

EQUIPMENT: Mounded LPG Storage unit: 1x600 MT AT CHERLAPALLI

LPG PLANT

Design Code BS PD 5500, category 2003 SMPV (U)

Rules 1981 - OISD 150

I/D 6000mm Overall length: 48500 mm

Capacity: 1111 m

3

(Water) / 600 MT (LPG)

Sp. Gravity : 0.54

Empty weight ; 226 MT

Flow : 45 cu.m./hr

DESIGN & CONSTRUCTION DATA

Working Pressure (at top) 11.0 (max.) Kg/cm

2 g

MATERIAL SPECIFICATION

Shell stiffener

Design pressure, (internal/external) 14.5 Kg/cm

2 g including static head Heads

Pressure Drop NA Kg/cm

2 g

Nozzles

SA 537 CL.1

SA 537 CL.1

Pipe : SA 333 Gr.6

Flange : SA 350 LF.2

Working temp. 47 (max.) o

C Studs/ nuts: SA 320 Gr L 7/ SA 194

Gr.7/ Gr.7

Fasteners

Gasket: SSSPWDAF with external rings

Design temp. (-) 27 to 55 o

C

Manhole

Plate: SA 537 CL.1

Flange/ cover: SA 350 LF.2

Corrosion Allowance 1.5 mm Pipe: SA 333 Gr.6

Internals

Weld Joint Efficiency 1 Nuts/ bolts: SS 304

Post weld heat treatment

Radiography

PWHT

Test. Hyd/Pne.Kg/cm

2 g

Complete vessel stress relieving

100% (before & after PWHT)

As per Code

As per Code

Reinforcement pads: SA 537 CL.1

Structural Attachment: SA 537 CL.1

Name plate: SS 304

Bend/ elbows: SA 333 Gr.6

Cathodic Protection ECCP 14026-PNND-CP40-TS02/R-01

Earthquake specification/ zone: IS-1893/ zone as per location

Painting / Coating

Construction

Water capacity

NOZZLE SCHEDULE

As per 4023-PNND-CP40-TS01/R-0

Cylindrical shell with hemispherical dish ends

1111000 ltrs

NAME

N1

QTY DESCRIPTION

1 Liq. Inlet/ Outlet

NB

150

PIPE

SCH/THK RATING TYPE FACE

SCH 80 300#

FLANGE

WN RF

RF PAD

300 OD X 23

LOCATION

Shell

REMARKS

With Comp.

Flange

N2

N3

1 Vapor inlet

1 Vapor outlet

150 SCH 80 300# WN

150 SCH 80 300# WN

RF 220 OD X 16 Dome A - do -

RF 220 OD X 16 Dome A - do -

N4 1

Radar gauge with multipoint temp

150 SCH 80 300# WN RF 260 OD X 16 Dome A

N5 1 High Level Alarm 100 SCH 80 300# WN

N6.N7 2 Safety Valve 150 SCH 80 300# WN

N8

N9

1 Pressure Gauge 50 SCH 80 300# WN

1 Press. Transmitter 50 SCH 80 300# WN

150 SCH 80 300# WN N10

N11,12

N13

1 Servo Gauge

2

Multi spot temp. gauge

1 Spare nozzle

50

150

SCH 80

SCH 80

300#

300#

WN

WN

RF 220 OD X 16 Dome B

RF 220 OD X 16 Dome B

With Comp.

Flange

RF 125 OD X 16 Dome A

RF 125 OD X 16 Dome B

RF 300 OD X 22 Dome A

RF 125 OD X 16 Dome A,B

M1

M2

1 Manhole

1 Manhole

600 16 THK 300# WN

600 16 THK 300# WN

RF 300 OD X 22 Dome A

RF

1450 OD X

22

Shell

RF

1450 OD X

22

Shell

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Appendix 2.2 Specifications of LPG

Table 1d LPG Specifications

Sl.

No

1

2

3

4

5

6

7

Characteristics

Vapor Pressure at 65 C, kgf/cm g

Volatile evaporation temperature in C, for 95% by volume at 760 mm Hg pressure, Max.

Total volatile sulfur percent by mass

Copper strip corrosion at 38

Hydrogen sulfide

Dryness

Odor

C for 1 hour

Requirement for commercial

Butane-Propane Mixture

16.87 Max.

2

0.02

Not worse than No. 1

Absent

No free entrained water

Level 2

Detailed Material Safety Data Sheet for LPG is given in Appendix 2.3.

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Appendix 2.3 Material Safety Datasheet

Chemical Name: Liquefied Petroleum Gas

Formula: C

3

H

6

- C

3

H

6

- C

4

H

10

Alternate names:

CAS No.: 68476-85-7 UN No.: 1075

LP Gas; Mix of Propane/ Butane; Bottled gas; Cooking gas

PHYSICAL & CHEMICAL PROPERTIES

Molecular Weight

44.00

Boiling Point (

C))

– 40.0

Melting Point (

C – 46.0

Vapor Pressure (bar)

NA

Physical State (at 20

C) Gas

Specific Gravity (liq)

0.5620

Specific Gravity (vap) (air = 1)

Heat of Combustion

1.5

46013000.00

Heat of Vaporization NA

General Characteristics

Colorless gas at room temperature, it can have odor like natural gas. Mercaptans added for odor warning

NFPA Ratings

NH (Health) 1 NF (Flammability) 4 NR (Reactivity) 0

Flash Point (

C)

Auto Ignition Point (

C)

FIRE & EXPLOSION HAZARDS

-104.44

466.11

Flammable/ Explosive Limits

Lower 2 Higher 10

Flammability Explosivity Combustion Products

Highly flammable material. It is a dangerous fire hazard when released in air as it will flashback along vapor trail

Sensitive to shock & static electricity

Emits CO & CO

2

REACTIVITY DATA

Incompatible Material

Avoid contact with oxidizing agents

TLV/ MAC (ppm) 1000

HEALTH HAZARD DATA

IDLH (ppm) 19000

Thermochemical Data

LD

50

(g/kg) na

TOXICITY

An Asphyxiant. High concentrations cause rapid respiration, mental dullness, poor judgment, incoordination, nausea & unconsciousness. Contact with liquid causes frostbite

(pg 1)

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Chemical Name: Liquefied Petroleum Gas

PREVENTIVE MEASURES

Fire

Keep vessels/ cylinders closed. Do not allow gas to leak out. Keep away from heat, sparks & flame.

EMERGENCY

Extinguishing agents

Stop flow of gas. Do not use flame to detect leak.

Use dry powder or CO

2

to extinguish small fires.

Allow gas to burn under control

First aid Explosion

Keep containers cool with water spray

PPE

Do not allow the gas to leak out.

Use gas mask, full protective clothing

Air

ENVIRONMENTAL IMPACTS

Water

Mammals Marine life

Disposal

Evacuate area; eliminate sources of ignition. Supply maximum air ventilation. Stop leak or remove leaky vessel to open, remote area. Disperse or dilute vapors with water spray

HANDLING & STORAGE

Packing

Cylinders

Enforce strict

ANY OTHER INFORMATION

observance

Periodic inspection/ testing of controls recommended. of

Storage

Store in tightly closed cylinders in cool, well ventilated area away from heat, sparks safety

Land

Others

procedures.

(pg 2)

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Appendix 3.1 Fire, Explosion and Toxicity Index Worksheet

Name of Plant

Manufacturing Unit:

Bharat Petroleum Corporation Limited (BPCL)

Proposed Additional storage at LPG bottling Plant

Material in Unit

Location

LPG

Cherlapalli. Andhra Pradesh

State of Operation

Normal operation

Storage Unit

Date 12/03/08

Material Factor

General Process Hazards

Base Factor

A) Exothermic Chemical Reactions

B) Endothermic Processes

C) Material Handling and transfer

D) Enclosed or Indoor process units

E) Access

F) Drainage and spill control

General Process Hazards Factor (F

1

)

Special Process Hazards

Base Factor

A) Toxic Material(s)

B) Sub-Atmospheric Pressure

C) Operation in or near Flammable Range

1. Tank Farms Storage Flammable Goods

2. Process Upset or Purge Failure

3. Always in Flammable Range

D) Dust Explosion

E) Relief Pressure

F) Low Pressure

G) Quantity of Flammable/ Unstable Material

1. Liquids or Gases in Process

2. Liquids or Gases in Storage

3. Combustible Solids in Storage, Dust in Process

H) Corrosion and Erosion

I) Leakage - Joints and Packing

J) Use of Fired Equipment

K) Hot Oil Heat Exchange System

L) Rotating Equipment

Special Process Hazards Factor (F

2

)

Process Unit Hazards Factor F

3

= (F

1

x F

2

)

Fire and Explosion Index (F

3

x MF)

Degree of Hazard

Toxicity Index Value (TI)

Penalty Factor Range

1.00

0.30

– 1.25

0.20

– 0.40

0.25

– 1.05

0.25

– 0.90

0.20

– 0.35

0.25

– 0.50

Penalty Factor Range

1.00

0.20

– 0.80

0.50

0.50

0.30

0.80

0.25

– 2.00

0.00

0.20

– 0.30

0.10

– 10.00

0.10

– 10.00

0.10

– 10.00

0.10

– 0.75

0.10

– 1.50

0.10

– 1.00

0.15

– 1.15

0.50

Mounded Storage

Vessel

21

Penalty Factor Used

1.00

0.00

0.00

0.50

0.00

0.00

0.00

1.50

Penalty Factor Used

1.00

0.20

0.00

0.50

0.00

0.00

0.00

0.00

0.00

0.00

1.47

0.00

0.10

0.00

0.00

0.00

0.00

3.27

4.90

102.9

Intermediate

3.77

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Appendix 3.2 Fire Damage Modeling & Criteria employed

Impact of Thermal Radiation

The damage effect due to accident release of a petroleum product, such as motor spirit, arises primarily from fire and/ or explosion. Damage criteria for people and property from effects of fire are known. They are expressed in terms of radiation intensity, and sometimes as a power dosage. The effect on people is expressed in terms of the probability of death and different degrees of injury for different levels of radiation. The effect on buildings, natural surroundings and equipment is measured in terms of the probability of ignition; this is particularly important for wooden structures. In Table 3.2.1 below, the radiative or incident flux is related to the levels of damage; this table is based on observations of large fires.

Incident Heat Flux kW/m

2

37.5

25.0

12.5

4.0

1.6

Table 3.2.1 Impact of Thermal Radiation

Type of Damage Caused

To Equipment To People

Damage to process equipment.

Minimum energy to ignite wood at indefinitely long exposure without a flame.

100% lethality in 1 min

1% lethality in 10 seconds

100% lethality in 1 minute.

Significant injury in 10 seconds.

Minimum energy to ignite wood with a flame; melts plastic tubing.

1% lethality in 1 minute. First degree burns in 10 seconds.

Causes pain if duration is longer than 20 seconds but blistering is unlikely.

Causes no discomfort on long exposure.

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Appendix 3.3 Results of Consequence Analysis

Dispersion Modeling

Dense dispersion model was used to calculate the extent of dispersion up to Lower Flammable

Limits (LFL). The most pessimistic meteorological conditions (wind speed

2.2 m/s, stability class F) and the prevailing wind direction were taken for dispersion simulations. The amount in the flammable limits was considered for calculation of pressure effects.

A Scenarios considered for Storage vessels

Scenarios considered for consequence calculations for the mounded LPG storage vessels are:

 Leak/ rupture of the bottom liquid lines to the tank lorry/ filling shed

 Leak/ rupture of the vapor lines to the tank lorry/ compressor

 Leak from safety relief valve of the mounded storage vessel

Case 1 - Leak/ Rupture of Liquid lines

Two types of leaks have been considered; the first located at the point of connection between pipe and vessel and the second located on the pipe a few meters away from the vessel. In the first case, the LPG will be released as a continuous stream of liquid, while in the second, 2phase flow (liquid and vapor) will occur from the location of the leak.

The leaked material will disperse forming flammable clouds down wind. Dense dispersion model was used to estimate the extent of dispersion.

Case 2 - Leak/ Rupture of vapor line

In this scenario, 100% leak of the vapor outlet line located at the top of the vessel is considered. An average discharge rate was calculated using outflow models. The material disperses as continuous vapor forming flammable clouds down wind.

Case 3 - Leak from safety relief valve of the vessel

In this scenario, 100% leak of the safety relief valve on the vent located on the top of the vessel is considered. An average out flow rate was estimated from stack release models. The material disperses as continuous vapor forming flammable clouds down wind.

The summary of the results of the consequence calculations for the scenarios visualized for the vulnerable units are given in Tables 3.3.1a & b.

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33

RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Event Reference No.

Scenario

1a. 100% release from

Bottom (liquid) pipe section away from vessel

1b. 20% release from liquid pipe section away from vessel

2a. Top Vapor Line 100% release from vapor line

2b. 20% release from top vapor line

3. Safety Relief Valve 100% release from Stack 10-m above ground level

4. 100% release from the liquid line from road lorry tank to bullet

150

150

150

150

150

150

Pipe size mm kg/s

Table 3.3.1a Damage distances from Jetfires

Discharge rate

Thermal radiation inside jet kW/m

2

Length m

Width m 37.5 kW/m

2

Damage distances (m)

12.5 kW/m

2

DW CW DW CW DW

4 kW/m

2

CW

11.7 92 39 3 41 5.5 44 14 48 27

2.34

17.7

3.54

4.16

(rate of SRV)

6.6 (Filling rate)

108

77

108

94

103

18

47

21

23

29.5

1.5

4

1.9

2

2.5

19

49

23

25

31

3

5.6

3.8

3

5

21

52

25

27

34

8

14.5

9

9

12

23

56.8

27

29

37

14

22

29.3

17.2

19

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Table 3.3.1b Damage distances from Flashfires

Event Reference No.

Scenario

1a. 100% release from Bottom (liquid) pipe section away from vessel

1b. 20% release from liquid pipe section away from vessel

2a. Top Vapor Line 100% release from vapor line

2b. 20% release from vapor line

3. Safety Relief Valve 100% release from Stack 10-m above ground level

4. 100% release from the liquid line from road lorry tank to bullet top

Pipe size

150

mm

150

150

150

150

150 6.6

Release rate

11.7

2.34

17.7

3.54

4.16

kg/s

2F

2F

2F

Wind velocity &

Stability

2F

2F

2F

-

28

-

-

8

LFL distance (DW)

11

m

10

Cloud radius

(CW)) m

-

18

-

-

7.3

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RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Appendix 3.4 Location of Sources of Ignition within the BPCL Installation

Proposed Plant Location on plot plan

(X, Y)

Distance from proposed mounded storage vessels (m)

Safeguards

LPG Pump comp shed

Empty/ Filling Shed

Filled cylinder Shed

Bulk unloading bays

Electric sub-station

145,117

172,200

224,200

204,84

269,34

29

61

109

91

181

Enclosed;

Flameproof motors & junction boxes

Flameproof equipment

Anti Static flooring

Spark arrestors

Enclosed; all electrical cables underground

Air compressor CW pump house

DG Set room

241,34

156

Transformer fence

Fire water

Pump house with

General plant area

257,34

297,33

337,145

166

203

213

Enclosed; all electrical armored cables underground, earthed

Fenced; Earthing; located in delicensed area

Enclosed; all electrical cables armored with FLP gland

Accumulation of Static Electricity Earthing of bullets, mounded storage vessels, Tanks, pumps and piping

Maintenance

Hot work

Non-sparking tools used

Permit system in place.

External to plant area Orientation Safeguards

Traffic on Highway South Green belt

All electrical fixtures, drive units and motors within licensed area are flameproof, and conform to IS 2148.

Sources of Probability values used in the report

CPQRA , LOPA (pg 71), Risk Analysis Report

Probability of Ignition for Continuous Release

Immediate ignition leading to Jetfire

Delayed ignition resulting in Flashfire

No Ignition

0.2

0.05

0.75

RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Appendix 3.5 Population Distribution at the site

The population within the facility consists of employees and contract labor working in the existing plant. Details of the distribution are listed below

Table c Distribution of personnel within the LPG installation

Sl. No Location

Day shift

1. Filling shed

2. Administration

3. Security

4. Amenities block

Total

Night shift

Security

Number of operating personnel

23

3

11

8

3

1

Since the area has been designated for industrial purposes, the density of habitation is relatively low in the vicinity.

RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Appendix 4.1 Fire Detection/ Protection System

The fire detection/ protection system for the proposed mounded storage area will be as follows;

AUTO FIRE DETECTION/ PROTECTION SYSTEM

Automatic fire detection and /or protection (Fixed) system based on heat detection through quartz bulbs will be provided. Sensors will be installed at all critical places as below: a) One detector will be provided on each exposed portion of the vessel. b) One detector will be provided near ROV on all liquid lines.

The actuation of pressure switch on any one of above said detector on or around the proposed mound will initiate the following:

-

An audiovisual alarm at the local/ main control panel and fire water station, indicating the fire.

-

All ROVs on the affected vessel will close.

-

LPG pumps and compressors in LPG storage area will trip.

-

Sprinklers operate.

In addition, devices for initiating all the above actions will be provided on remote operating panel and also in field at safe location to enable manual actuation.

GAS DETECTION SYSTEM

Gas detectors will be placed at critical locations in the proposed LPG storage area such as near the ROVs, in inspection tunnel, inside the nozzle box enclosure/ dome connection, near water draining/ sampling points.

Audio-visual alarms showing the location of gas leakage will be provided on the control panel.

First level alarm will be set at 20% of Lower Explosive Limit (LEL) and second level alarm at 60

% of LEL.

FIRE FIGHTING SYSTEM

The existing fire fighting system will be extended with hydrant (s)/ monitor (s) for adequate coverage of unprotected portions exposed to thermal radiation including the top of the proposed mound and product pipelines.

Fire fighting and other Safety Measures at the Existing Plant

Fire Mitigation Measures

Fire fighting facilities on site consists of five diesel engine driven firewater pumps of

616 kl/hr each (3 main and 2 standby). Two jockey pumps of capacity 10 m

3

per hour each (One main plus one standby) are provided to maintain residual pressure.

Three firewater storage tanks of 2733 KL capacity each are located near the fire water pump house.

All safety & fire fighting facilities are provided as per OISD (Oil Industry Safety

Directorate) standards.

Details of existing safety equipment at LPG plant

The fire main ring is always kept pressurized at 7 kg per cm2 and hooked up with the fire fighting system of BPCL Depot and IOCL LPG Plant.

31 Nos. Monitors and 37 Nos. of Double Hydrants provided in 28 Hose Boxes with

Hoses 2 Nos. of 15 meters length and one nozzle each.

RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

MV Protecto Spray Sprinkler is backed up by 18 Nos. deluge valves at Plant.

DV Nos

01-05

06-13

14

15

16

17-18

Location

New Filled Shed

Filling Shed

Tank Lorry Gantry

LPG Pump House

Mounded Bullet

Above Ground Bullet

Emergency Shut Down System (ESDs)

These are provided at the various strategic points through out the plant. In the event of leakage of Gas/Fire, due to the manual breakage of the glass, main control panel will de-energize and will trip the ROVs, LPG Pump, LPG Compressor and Evacuation Compressor.

ESD Locations (11 Nos.) are given below:

ESD No

1.

2.

3.

4.

5.

6.

7-11

Location

Admin Building

Time Office

Air Compressor Room

Tank Lorry Gantry

Mounded Bullet Area

LPG Pump House

Filling / Filled Shed

Manual Call Points (MCP) MCPs are provided at the strategic points in the plant.

If the glass of the MCP is broken, it operates the electrical siren and also gives the indication in the Fire Annunciating Panel. It also trips all the Plant operations.

MCP Locations (14 Nos.) are given below:

MCP Nos Location

5.

6.

7.

8.

1.

2.

3.

4.

Admin Building 1st Floor

Admin Building Portico

Time Office

MCC Room

Fire Water Pump House

Tank Lorry Gantry

Mounded Bullet Area

LPG Pump House

RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

9-14 Filing & Filled Shed

Hydrants, Monitors & Fire Extinguishers at Plant:

Hydrants

Monitors

10 Kg DCP Fire Ex

75 Kg DCP Fire Ex

CO2 Fire Ex

37

31

98

10

07

Communication Systems IS Page phones of Andrew Yule make are provided at

10 points through out the Plant and Administration & Security Blocks to have effective communication.

Page phone locations:

1) Main Gate

2) Time Office

3) Admin Building

4) Filling Shed

5) Filled Cylinder Shed

6) MCC

7) Air Compressor Room

8) Fire Water Pump House

9) Tank Lorry Gantry

10) LPG Pump House

No of units

01

01

01

01

01

01

01

01

01

01

VHF (13 Nos.) are also available for effective communication. Motorola make.

Gas Monitoring system (GMS) GMS is provided in the plant and sensors are positioned at strategic points in the areas where LPG is handled / possibility of LPG leakage. The system is set in such a way that in the event of LPG leakage, if the concentration of the LPG reaches 30% of the LEL, it senses and gives an indication in the panel. At 50% and 70% of LEL it gives the hooter sound to alert the people. Pentax make - 66 Nos. of GMS Sensors are provided at strategic locations.

Testing & Calibration: All safety equipment and other instruments are tested / calibrated.

Safety Features on Bullets: Safety Relief Valves, High Level Alarm & Remote

Operated Valves provided on the storage vessels.

LPG Road lorry tanks: Road lorry tank provided with excess flow check valves

RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Flame Proof Fittings: All electrical fittings in hazardous area are flame proof/ intrinsically safe.

Spark Arrestors: All vehicles plying in licensed area provided with Spark

Arrestors.

Earthing: Earthing & bonding of all equipment.

Compound Wall: A 3.0 m high Boundary wall and 0.6 m high barbed wire fencing provided all around the plant.

DCMP: On site Disaster Control Management Plan prepared.

Fire Drills: Regular Safety and Fire Drills conducted as per OISD standards.

Safety Audits: Regular Safety audits are carried out as per OISD standards.

House Keeping: Good housekeeping, Hot work/ Cold work permit system as per

OISD standards would be followed.

Security System: Round the clock securities are placed in the plant. Security checks are carried out at the gate & at the entry to the hazardous area.

Training: Personnel trained to deal with emergency measures & transportation of hazardous cargo continuously and periodically in line with OISD standards.

Transport Emergency (TREM) card will be given to the tank lorry personnel.

RISK ANALYSIS FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Annexure I HAZOP STUDY REPORT

HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

ANNEXURE 1 HAZARD & OPERABILITY (HAZOP) STUDY

A.1 Preamble

Hazard and Operability Study (HAZOP) was conducted for the proposed 600 MT mounded bullet and the activities associated with the storage of LPG. The aim of the study is to identify any hidden design inadequacies and correct it before the commencement of the construction.

The principle of HAZOP is that accidents occur when conditions deviate from the desired intentions. HAZOP therefore starts by understanding the design intentions of a particular unit and finds out meaningful deviations that can occur in the process. The practice then is to understand these deviations and the consequences of these deviations, and detect which of these consequences will result in a major hazard.

A.2 Conduct of the HAZOP sessions

The HAZOP review was conducted for all the major sections of the proposed mounded storage unit using the conventional approach (identification of node/ deviation/ causes, corresponding consequences and safeguards, etc.). The exercise is an outcome of the insights and experience of the personnel who attended the review.

For each of the nodes examined, the hazards were identified and the possible causes and effects of potential accidents involving these hazards were evaluated.

A.3 Nodes considered for the HAZOP Study

The HAZOP study covered three major sections: the unloading operation, the storage vessel and the transfer operation through the pump.

Based on the intended objective of the various sections of the pipeline, the storage and associated pipelines have been divided into nodes for the conduct of a HAZOP study as listed in Table A.1. The control strategies and built-in safety features of the sections were closely examined using the process flow diagram.

Sl No

1.

2.

3.

4.

Table A.1

Node

List of Nodes used in the exercise

Intention

Loading of Mounded Storage Pipeline Transfer (PLT) of LPG from GAIL

P/L to Mounded Bullet

Vapor Line between Mounded Storage and

Tank Lorry Truck

LPG Liquid Transfer Line from Tank Lorry to Mounded Bullet

LPG Liquid Transfer Line from Train

Wagons to Mounded Bullet

To maintain pressure in road lorry tank for unloading liquid and reduce vapor pressure on completion of unloading

Loading of LPG to Mounded Storage from Tank Lorry

Loading of LPG to Mounded Storage from Train Wagons

The HAZOP worksheets for each node are given in ANNEXURE A.1

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

A.4 Reference Documents

The HAZOP study was performed on all the completed design issue of Piping and

Instrument Diagrams of the facilities. The documents referred to in the study are listed below

1. Specifications of LPG (Appendix 2.2)

2. MSDS (Appendix 2.3)

3. Mounded Storage vessel: Schematic layout P&ID No: E&P/STD/MSV/003

(Fig 1.1)

4. P&ID for LPG Bottling Plant BPC/LPG-02 (Fig 2.1)

A.5 Parameters adopted for the study

Each section was considered for divergences from normal design practices. The parameters (flow, pressure, maintenance, etc.) relevant to each node are studied in conjunction with guidewords (no, more, less, misdirected, etc.) to generate deviations from design operating conditions (no flow, more flow, misdirected flow, etc.). The possible causes of such deviations are listed together with the consequences with respect to hazards or operability. The safeguards that reduce the possibility of undesirable deviations occurring or to limit the severity of the consequences are considered by the team to determine what actions to recommend, if any, to improve the safety or operability of the process system

The main parameters, considered along with the deviations from normal operating conditions, have been presented in Table A.2.

Parameter

FLOW

PRESSURE

LEVEL

PHASE

TEMPERATURE

MAINTENANCE

CORROSION

UTILITIES

PROCEDURE

Table A.2

COMMUNICATION FAILURE

Details of HAZOP worksheets

Deviations

No Flow

More Flow

Less Flow

Reverse Flow

Misdirected Flow

Contamination (As well as)

High Pressure

No/ low Pressure

No/ Low Level

High Level

Two phase flow

High

Low

Poor Maintenance

More corrosion

Loss of power

Loss of communication

Wrong communication

Non - adherence to standard operating procedures

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44

MANUAL FILLING MACHINE

47.5/35/19/14.2/5/LOT/BMCG DOSING

FIG 2.1

TANK LORRY GANTRY

HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

P&ID FOR LPG BOTTLING PLANT SHOWING RECEIPT, STORAGE & DISTRIBUTION NETWORKS

FITTED TO ROOF

TANK LORRY GANTRY

TG

MOUNDED STORAGE VESSELS

BULLET AREA

TG

TG

ABOVE GROUND BULLETS

BULLET AREA

LPG LINE

FROM GAIL RT

BLOW OUT

AIRVENT

TSV

COLD FLARE

SYSTEM

TSV

PRS.FLOW

RT

PV2 PV1

PV3

BULLET 1

TG

BULLET 2

TG

BULLET 3

TG

50

40 50 40

50

50 40

50

50 40

50

50 40

50

50 40

50

50

50

V2

1OO 1OO

ROV 'L'

ROV 'V1'

ROV 'V2'

150V2

200V1

C R

150V1

150V2

20

200L

150 150

350L

PLUG VALVE

NRV

NRV

3 WAY VALVE

V1

V2

V1

V2

200L LQUID SUCTION LINE

150V COMP.SUCTION/DISCHARGE

150V COMP.SUCTION/DISCHARGE

150L TO TANK LORRY GANTRY

150L TO TANK LORRY GANTRY

150L TO TANK LORRY GANTRY

PLT LIQUID LINE AGSV

PLT LIQUID LINE MSV

80L CAROUSEL RETURN

PCV

BPCL ROV

PT

P.SWITCH

5

15

PUMP DISCHARGE

AVCU1

VENT

CORRECTION UNIT

FROM CORRECTION UNIT

FILLING SHED

SRV

CAROUSEL 1

SRV

TO CAROUSEL INLET

CAROUSEL 2

CORRECTION UNIT

AVCU1

VENT

V1

V2

X Y

Z

150 L PUMP DISCHARGE

PG

PG

NEW PUMP SET-1 NEW PUMP SET-2

LPG PUMPS

150

PG

PUMP SET-1

200 L PUMP SUCTION

PG

PUMP SET-2

4-WAY VALVE2

V2

4-WAY VALVE1

V1

Y TYPE STRAINER

150

150

150

150

SV1

SV2

DV1

DV2

TG

TO

VENT

SUCTION

SEPARATOR

TG

TG

TO

VENT

LPG COMP1

COOLING

WATER

FLOW GAUGE

COOLING

WATER

TEMP.GAUGE

LPG COM2

LUBE OIL

SWITCH WITH

PR.GAUGE

COOLING

WATER

FLOW GAUGE

COOLING

WATER

LUBE OIL

SWITCH WITH

PR.GAUGE

TEMP.GAUGE

LPG COMPRESSORS T/LG

TG

KOD

COMPRESSOR

TG

KOD

COMPRESSOR

TG

KOD

COMPRESSOR

LPG LIQUID LINE GREEN COLOUR

LPG VAPOR LINE BLUE COLOUR

COMPRESSOR

KOD

TG

TG

GLASS

SIGHT

TO BULLET

SRV

CYLINDER

HLA

HLA

4-WAY VALVE

TO VENT

150L

100L

PUMP DISCHARGE 150L

CAROUSEL RETURN 100L

350L

300V

SIDING COMPRESSOR HOUSE

LIQUID FROM SIDING

150V2

200V1

SIDING

LEGEND

GATE VALVE

GLOBE VALVE

PLUG VALVE

CHECK VALVE

BALL VALE

FOUR WAY VALVE

TG

EXCESS FLOW CHECK VALE

Y TYPE STRAINER

BLIND FLANGE

REDUCER

TEMPERATURE GAUGE

PRESSURE GAUGE

TG TEMPERATURE GAUGE

PRESSURE GAUGE

ORIFICE PLATE

FILTER

REMOTE CONTROL VALVE

WITH HAND WHEEL

THREE WAY VALVE

THERMAL SAFETY VALVE

MULTIPORT SAFETY RELIEF VALVE

DIP LEVEL GAUGE

HIGH LEVEL ALARM

ROCHESTER % GAUGE

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

A.6 Results of the HAZOP study

The nature of the hazards identified during the HAZOP brainstorming sessions are detailed in the Worksheets given in section A.7. Significant threats have been identified from the HAZOP study that can contribute to the realization of the hazardous scenario of loss of containment and release of pressurized LPG. These are listed below along with the existing safeguards that contain or mitigate the hazard

Sl no Threat

Table A3 Identification of threats from the HAZOP worksheets

Safeguards Reference in Worksheet

1

2

3

Over Pressurization of pipeline

Pipeline leak

Possibility of fire/ dispersion at flanges

Pressurization of bullet

 High pressure trip provided by GAIL (pressure sensor before the GAIL ROV inside the BPCL premises)

 TSV will pop-up

 PI provided across the strainer

 SOP - inspection and cleaning done quarterly

 Temperature safety valves (TSV) on headers & discharge lines available

1 –

No flow

1 –

No flow

1 –

No flow

1 –

No flow

 Preventive maintenance being carried out

 Gas detectors/ alarm provided at GAIL as well as bullet area

 ESD/ MCP provided at the plant will close the ROV's (if the leak is after the

ROV at PLT)

 Checklist

 Work permit procedure

 Periodic electrical audit

 Hooter will sound at high high level in the storage vessel

 Two SRV's provided on the vessel (13.6 kg/cm2 pops-up)

1 –

No flow

 Pipeline designed for 300 class (49 kg/cm2 max.)

 ROV will close at high high level

 Pressure gauge, Servo-level gauge/ Rochester gauge, and high level alarm available on the bullet.

 Non-return valves available on all liquid lines

1, 3 – more flow, misdirected flow

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46

HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Sl no

4

5

6

7

Threat

Possible ingress of air and formation of explosive mixture

Leak from storage unit/ overfilling

Safeguards

 ROV of storage tank in/out

 Regular pressure testing of hoses and maintenance of records

 Operator available at pump house during the operating hours

Pressurization of loading hose (tank lorry)

Vacuum generation in header

Possibility of air ingress and formation of explosive mixture

 Locks provided at the drain valves

 Gas detectors/ alarm provided at drainage point

 Bullet levels are monitored

 High level and high pressure alarms are provided on bullets

 Checklist available for line-up procedure

 ROV panel trip protection

 Gas detectors are provided at vulnerable areas

 Valve can be closed at the storage tank.

 Level monitored from the Control Room.

 Automatic tank gauging (ATG) system has High level and Low level trip

 unloading motor is stopped manually before the high level (85%) is reached

 PI on compressor discharge

 High discharge pressure trip at 9.5 kg/cm2 of the compressor

 SRV provided at the compressor discharge

 EFCV provided on the vapour, liquid hose line of the tank lorry

 Activation of road lorry tank safety valve

 High pressure trip provided at the compressor

 Low suction trip on compressor and low pressure alarm

 Open/ Close visual indication for ROV

 Regular maintenance schedule

 Strainer maintenance schedule followed

Vacuum generation downstream of strainer and implosion of hose

Possibility of air ingress and formation of explosive mixture

Reference in Worksheet

2 –

No/ low pressure

1 – No/ less flow

4 -- Communication

2 High pressure

1 –

No flow

2 – no/ low flow

1 –

No flow

RCE Chennai

47

HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Sl no

8

9

RCE Chennai

Threat

Over pressurization of road lorry tank

Possibility of leak and formation of flammable mixture

Safeguards

 Unloading operation monitored by operator

 Excess flow check valve available on road lorry tank

 Non-return valves available on all liquid lines

 TSV on headers & discharge lines available

 High discharge pressure trip at 9.5 kg/cm2 of the compressor

 SRV provided at the compressor discharge

 Regular pressure testing of hoses and maintenance of records

 Training provided to road lorry tank drivers

Pressure build-up in the wagons & pipeline

Possibility of leak and fire/ flashback to tank wagons

Pipeline rupture bet., the outlet valve and the compressor (approx.. 1m)

Reference in Worksheet

1, 3

Low pressure

Misdirected flow

High pressure

 PSV provided on wagon (no trip) (13.6 kg/cm2

 Compressor high discharge trip (10.5 kg/cm2) Pipe is designed for 28 kg/cm2

 NRV provided close on the liquid line on the gantry

 Compressor high discharge trip (10.5 kg/cm2)

 TSV will pop off

 TI & PI (local) provided on compressor outline line,

 Pressure gauges and switches are calibrated every 6 months

4

More pressure

 Separation distance,

 SOP

 Compressor high discharge trip (10.5 kg/cm2). Pipe is designed for 28 kg/cm2

Buckling on the pipe / Air ingress into the system and flammable mixture formation of

 Unloading operation monitored by operator

 Gas detectors available,

 Start up check list available

 Local pressure gauge provided, low pressure trip is available for below 1.5 kg/cm2

 EFCV provided at wagons

4

Less pressure

48

HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

It was noted by the HAZOP team that most of the hazards have sufficient safeguards for the prevention or mitigation of an identified hazard.

The HAZOP study has identified several causes that may result in the release of pressurized LPG into the atmosphere. Failures of the pipeline/ flanges or at instrument connections on vessel or line may be the initiating cause for loss of containment leading to possible fire, or dispersion. The potential releases and consequences are quantified in the risk analysis study.

RCE Chennai

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

A.7 HAZOP Worksheets

Company

Facility

Project

Node #1

Intention

Drawing Nos.

Date

DESIGN

NORMAL/ OPERATING

BHARAT PETROLEUM CORPORATION LIMITED

CHERLAPALLI LPG BOTTLING PLANT

HAZOP, SAFETY REVIEW & RISK ANALYSIS STUDIES FOR THE PROPOSED NEW LPG MOUNDED BULLET (2x600 MT) AT CHERLAPALLI BOTTLING

PLANT, ANDHRA PRADESH

Pipeline Transfer (PLT) of LPG from GAIL to Mounded Bullet

Loading of Mounded Storage

P&I DIAGRAM DRAWING NO. being prepared

12/28/2010

PRESSURE

6-7 kg/cm2

TEMPERATURE

deg C

AMBIENT

PRODUCT

LPG

LPG

PHASE

LIQUID

LIQUID

Capacity of proposed mounded bullet = 600 x 2 MT

Headers of the existing liquid and vapour line (6 inch) will be extended to provide tapping to the proposed new bullets

Provision to fill all the bullets simultaneously is possible

From GAIL, pipe size is 6 inch

ROV provided at the entry of PLT controlled by BPCL, one more ROV provided which is controlled by GAIL

Parameter

Intention

Flow

Deviation Cause Consequences

To receive LPG product and provide buffer storage for bottling purpose

No/ less Flow ROV struck close during operation (loss of power)

Line gets pressurized at the upstream

No major consequence in

Safeguards Recommendations

High pressure trip provided by GAIL (pressure sensor before the GAIL ROV inside the BPCL premises)

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Parameter Deviation

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Cause Consequences

the downstream section

Strainer

Located after ROV blocked Line gets pressurized at the upstream

No major consequence in the downstream section

Safeguards

TSV will pop-up

PI provided across the strainer

High pressure trip provided by GAIL (pressure sensor before the GAIL ROV inside the BPCL premises)

SOP - inspection and cleaning done quarterly

Recommendations

Backpressure from the bullet/ ROV closed during operation

Line gets pressurized at the upstream

No major consequence in the downstream section

Pipeline leak/ TSV struck open

High pressure trip provided by GAIL (pressure sensor before the GAIL ROV inside the BPCL premises)

LPG leak

Gas slump at the ground level, potentially hazardous

Preventive maintenance being carried out

Gas detectors/ alarm provided at GAIL as well as bullet area

ESD/ MCP provided at the plant will close the ROV's

(assuming the leak is after the ROV at PLT)

ROV open in the inlet line of the other bullet

Unintended storage vessel will gets filled-up

Hooter will sound at high high level in the storage

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Parameter Deviation

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More flow

HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Cause

Plug valve passing on PLT to above ground tank line

Note: Intention is to load only mounded bullet

Consequences

Vessel gets pressurized

Unintended storage vessel will gets filled-up

Vessel gets pressurized

Safeguards

vessel

Two SRV's provided on the vessel (13.6 kg/cm2 popsup)

Recommendations

Ball valve in the Inlet PLT line at the bullet will normally closed

Hooter will sound at high high level in the storage vessel

Two SRV's provided on the vessel (13.6 kg/cm2 popsup)

Drain valve kept open

Operator error

LPG leak

Gas slump at the ground level, potentially hazardous

Locks provided at the drain valves

Gas detectors/ alarm provided at drainage point

Ball valve on the filling line of the same bullet kept partially open

Note; Can happen if the same bullet is lined up for filling

Part of the LPG from PLT will go to the suction of the pump

No major consequence

GAIL supplies LPG at a Pipe line/ Bullet gets Pipeline designed for 300

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Parameter

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Deviation

Reverse flow

Misdirected flow

Cause

pressure higher than 10-

12 kg/cm2/ malfunctions

PRV

Consequences

pressurized

Faster filling rate

Safeguards

class (49 kg/cm2 max.)

SRV (2 nos.) provided on the bullets

Recommendations

Pump trips at the GAIL end No major consequence as there is static pressure in the pipeline due to LPG

Connection between the bullets kept open when

PLT pump trips (due to siphoning)

Level attains equal between the tanks

NRV provided at the PLT inlet to the bullet

Ball valve on the filling line of the same bullet kept partially open

Note; Can happen if the same bullet is lined up for filling

Ball valve on the siding line kept partially open

Part of the LPG from PLT will go to the suction of the pump

No major consequence

Other bullets gets overfilled and pressurized

Note: This can happen when siding operation is being carried out

Vapour discharge line gets pressurized

Hooter will sound at high high level in the storage vessel

ROV will close at high high level

SRV (2 nos.) provided on the bullets

SOP to instruct the operator to close the ROV in the vapour line

Check vapour line to be designed for the maximum pressure of the GAIL inlet line

Ball valve on the TLD bypass line kept open

LPG will be received at the

TLD line

Hooter will sound at high high level in the storage vessel

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Node #2

Intention

DESIGN

NORMAL/

OPERATING

Parameter

Intention

Pressure

Parameter

Temperature

Deviation Cause Consequences

May pressurize the filling operation

Possibility of LPG overfilling

& pressurization

Safeguards

ROV will close at high high level

SRV (2 nos.) provided on the bullets

Recommendations

High Temperature High ambient temperature No major consequence during normal operation

May cause thermal expansion when in the line is under static condition (no flow of LPG)

TSV provided at several points on the pipeline

Vapor Line between Mounded Storage and Tank Lorry Truck

To maintain pressure in road lorry tank for unloading liquid and reduce vapor pressure on completion of unloading

Compressor capacity

TEMPERATURE PRODUCT PHASE

65 cfm deg C

AMBIENT (35 C)

LPG

LPG

LIQUID

LIQUID

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Deviation Cause Consequences Safeguards Recommendations

To maintain pressure in road lorry tank for unloading liquid and reduce vapor pressure on completion of unloading

No/ Low Pressure Incorrect position of valves

(four-way)

Bullet pressure increases

Possible ingress of air and

Operator available at pump house during the operating

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Parameter

Intention

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Deviation

High Pressure

Cause Consequences

formation of explosive mixture

Safeguards

hours

Recommendations

Passing at the 4-way valve Less amount of LPG to the compressor

Less discharge from the truck

Longer time for unloading

No hazard

Same as above ROV in the vapour line/ ball valve partially close

Road lorry tank vapor line valve shut with compressor in line

Possibility of damage to hose

Possibility of loss and dispersion of LPG

Possible formation of flammable mixture

PI on compressor discharge

High discharge pressure trip at 9.5 kg/cm2 of the compressor

SRV provided at the compressor discharge

Unloading with pressure in bullet high Possibility of damage to liquid hose line

Possibility of loss and dispersion of LPG

Possible formation of flammable mixture

EFCV provided on the vapour, liquid hose line of the tank lorry

Activation of road lorry tank safety valve

High pressure trip provided at the compressor

ROV closes at the tank lorry gantry

Pressurization in the vapour line from ROV to the compressor discharge

High discharge pressure trip at 9.5 kg/cm2

SRV provided at the compressor discharge

To maintain vapor flow for pressurizing compressor (unloading and cylinder filling)

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Parameter

Phase

Intention

Flow

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Deviation

Two-phase flow

Cause

High level in bullet leading to possible carryover of liquid (malfunction. of

HLA)

Consequences

Possible damage equipment

Safeguards

Knock out drum

Separator at compressor suction

Regular maintenance of drum and separator

Recommendations

Unloading vapour recovery) operation vapour & liquid hose are interchanged (during

Liquid enters the vapour line up to knockout drum

Compressor may be damaged

Trip provided for liquid level high in the knock out drum

To maintain vapor flow

No/ low Flow ROV/ NRV/ Isolation valves on vapor outlet fails shut/ malfunctions

Suction filter of compressor fully or partially choked

Possibility of vacuum generation in header

Possibility of air ingress and formation of explosive mixture

Low suction trip on compressor and low pressure

Open/ indication

Regular schedule

Close for alarm visual

ROV maintenance

Strainer maintenance schedule followed

Possibility of vacuum generation downstream of strainer and implosion of hose

Possibility of air ingress and formation of explosive mixture

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Node #3

Intention

DESIGN

LPG Liquid Transfer Line from Tank Lorry to Mounded Bullet

Loading of LPG to Mounded Storage by Tank Lorry

FLOW PRESSURE TEMPERATURE

deg C

PRODUCT

LPG

PHASE

LIQUID

NORMAL/

OPERATING

Parameter

Flow

Deviation

1 No/ less Flow

AMBIENT

Maximum 6 tank lorries can be unloaded into the mounded bullet simultaneously.

Intention

To load LPG to Mounded Storage from unloading tank lorry

LPG LIQUID

Cause

Wrong routing – flow diverted to other bullet or to transfer pump section/

Valve to the other bullet is passing/ Valve to the other bullet is kept open inadvertently

Consequences Safeguards Recommendations

If routed to bullet already containing sufficient LPG level, the bullet can get pressurized

Possibility of over flow from

Bullet levels are monitored

High level and high pressure alarms are provided on bullets the bullet, leading to release of LPG into

Checklist available for lineup procedure atmosphere and formation of

Possible joints flammable leak/ mixture fire/ dispersion hazard from pipe

ROV panel trip protection

Gas detectors are provided at vulnerable areas

One of the wagon is emptied out, vapour flows into the liquid line, causing

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Parameter Deviation Cause

*System of 2 vessels

(mounded storage/ road lorry tank) are balanced with interconnection.

Compressor operates on differential pressure basis.

Consequences

Over pressurization of road lorry tank/ bullet

Possibility of leak and formation of flammable mixture

Safeguards

High pressure trip in compressor

Pressure gauge, Servo-level gauge/ Rochester gauge, and high level alarm available on the bullet.

Excess flow check valve available on road lorry tank

Recommendations

Higher differential pressure in the line

Reduction in bullet pressure due to opening of safety valve on bullet

Filling of Mounded Storage at faster rate

As above

Loss and dispersion of LPG

Possible formation of flammable mixture

Pressure indication on bullet

Regular testing of maintenance of records

SRV and

Misdirected Flow external to the bullet

Rupture of hose due to high pressure in road lorry tank

Ball valve in the filling line passing (normally closed)

Loss and dispersion of LPG

Possible formation of flammable mixture

Non-return valves available on all liquid lines

Excess flow check valve on road lorry tank and ROV of storage tank in/out

Regular pressure testing of hoses and maintenance of records

High pump discharge Carousel return line provided

SOP to instruct the operator to monitor the parallel operation such as decantation by tank wagon or tank truck to prevent overfilling and pressurization of bullet

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Parameter

Intention

Pressure

Intention

Procedure

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Deviation Cause

Accidental pullaway of road lorry tank

Consequences

Loss and dispersion of LPG from tanker and bullet

Possible formation of flammable mixture

To maintain pressure in the line greater than the bullet pressure

Lower Pressure Leak at flanges/ TSV on pipeline pops open

Vapor leak

Safeguards

Training provided to road lorry tank drivers

Unloading operation monitored by operator

Gas detectors available

Regular pressure testing of valves and maintenance of records

Recommendations

Use of wedges on lorry tyres to prevent slip

Higher Pressure High External temperature

Block in line near outlet into bullet ambient Pressure rise in pipe section Temperature safety valves

(TSV) on headers & discharge lines available

Stoppage of flow and pressure rise in the truck

TSV on headers & discharge lines available

High discharge pressure trip at 9.5 kg/cm2 of the compressor

SRV provided at the compressor discharge

To conduct operations as per Standard operating procedures

Non-adherence to

Standard

Proper bonding and earthing of unloading

Possibility of fire/ dispersion at flanges if

Checklist

Work permit procedure

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Parameter Deviation

operating procedures

Cause

header not done leading to accumulation of Static

Electricity

Consequences

there is leakage

Improper procedure followed during draining activity

LPG leaks with water leading to loss and dispersion of LPG

Safeguards

Periodic electrical audit

Recommendations

Procedure for isolation

Excess flow valve available on the drain line

Gas monitor system

Node #4

Intention

DESIGN

NORMAL/

OPERATING

LPG Liquid Transfer Line from Train Wagons to Mounded Bullet

Loading of LPG to Mounded Storage from Train Wagons

FLOW PRESSURE

1.5 - 10 Kg/sq cm

3 - 5 Kg/sq cm

TEMPERATURE COMPOSITION (Product) PHASE

Propane & Butane Mixed - Liquid & Vapour

Propane (40)& Butane

(ABOVE 60)

Mixed - Liquid & Vapour

Maximum 16 wagons can be decanted at a time to the mounded bullet, the capacity of each wagon is 36.67 MT

Parameter

Pressure

Deviation Cause

More Pressure liquid lines on the wagon is closed/ valves on the gantry is closed vapour lines on the wagon is closed/ valves on the gantry is closed

Consequences

Pressure build-up in the wagons & pipeline

Pressure build-up in the vapor line

Safeguards Recommendations

PSV provided on wagon (no trip) (13.6 nil kg/cm2)

Compressor high discharge trip

(10.5 kg/cm2) nil Compressor high discharge trip

(10.5 kg/cm2). Design pressure is 28 kg/cm2 for the pipeline

Remarks

PSV setting is higher than compressor trip

PSV setting is higher than compressor trip.

Maximum design discharge pressure of compressor

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Parameter Deviation

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Cause

Inlet come off) valve of mounded bullet is closed/ ROV fails

(power failure, air line

Consequences

Line and wagon pressurized

Safeguards Recommendations

NRV provided close on the liquid line on the gantry

Compressor high discharge trip

(10.5 kg/cm2)

TSV will pop off nil

Wrong setting of compressor pressure or malfunctions of pressure system

Pressure & temperature build-up in the wagons & pipeline

TI & PI (local) provided on compressor outline line,

Pressure gauges and switches are calibrated every 6 months, nil

Remarks

External fire from POL area

External bushes (any time)

Fire fire under from the wagon/pipe due to combustible matter

Fire/Flash back to the

LPG wagon

Pressure leading

Pressurization entire line build-up radiation/flash back to

Separation distance, SOP Mutually activities identified exclusive to be

Bushes to be removed

(5m from the boundary wall) check the radiation distances between the bush fire and log rail wagon in PSV provided on wagon (no trip) (13.6

TSV on pipeline kg/cm2)

Ensure housekeeping

Composition varies

(i.e., if propane is more than butane)

Compressor valve is closed outlet

Line & vessel will be pressurized

Pipeline rupture bet., the outlet valve and the compressor

(approx.. 1m)

Valve on vapour outlet line in

Pipe rupture bet.

Comp and vessel

The system is designed for propane

Compressor high discharge trip

(10.5 kg/cm2). Pipe is designed for 28 kg/cm2

Compressor high discharge trip

(10.5 kg/cm2). Pipe is designed nil

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Parameter

Flow

Deviation Safeguards

for 28 kg/cm2

Recommendations Remarks

Accidental closing of the valves

(ROV/Manual valve)

Less Pressure Valves (compressor) in the suction line is closed

Pressure build-up

Decantation will not start, buckling on the Start up check list available. pipe will occur,

Air can ingress into the system and form flammable mixture

TSVs are provided

Compressor high discharge trip

(10.5 kg/cm2).

Pipe is designed for 28 kg/cm2 manufacturer’s protection for low press.

Check if the pipeline is designed for low pressure/vacuum

Compressor type - reciprocating comp.

Cause

mounded bullet is closed during vapor recovery

Consequences

Malfunctioning wrong or pressure setting compressor of the

Longer decantation Local pressure gauge provided, time, low pressure trip is available for below 1.5 kg/cm2 Air can ingress into the system and for flammable mixture

Check with compressor manufactures protection for low press.

More Flow

Leak at flanges/ TSV on pipeline pops open

Vapour leak CAN

MEET FIRE (3/4"

OUTLET)

No significant drop in

Unloading operation monitored by

Gas detectors available the pressure level operator

Rupture of pipeline

Higher differential pressure in the line

Vapour formation & fire cloud

Filling of LPG mounded bullet at faster rate

EFCV provided at wagons 3D Dispersion Modeling EFCV (50 mm = 38

Studies to be done m3/hr)

Unloading operation monitored by operator

EFCV provided on wagons

Calculate the max. rate when the diff. pressure is 7 kg/cm2

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Parameter Deviation Cause

Less/ No Flow No/less material in the unloading rail wagons

Misdirected

Flow

ROV in vapour line in shut position

Consequences

Static charges can built-up if the flow exits 7 m/s

Safeguards

High pressure trip in compressor

Recommendations

Longer time decantation

Low flow due to low pressure

Wrong routing - flow diverted to other mounded bullet or valve at the other mounded bullets are kept open inadvertently

Overflow in another mounded bullet

Reverse Flow Compressor trips or malfunctions

Product will go back to the liquid line

NRV provided

Remarks

Consider case where

NRV fails, ROV opened when LPG liquid in header line

Misdirected

Flow valve in the manifold kept open and the flow is directed to pump suction nil

Valves on the other mounded bullet kept open and connected other mounded bullet can fill - up, liquid will comes through the vapour line

High level alarm -mounded bullet, Stops the Compressor, all ROV will be closed

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Parameter

Temperature

Deviation

High

Temperature

Cause

High ambient temperature cycles during non-operating hours

Consequences

Contamination Water in the product Water will finally reach to LPG cylinders causing corrosion damage nil

External fire

Safeguards

Water draining procedure in the

Recommendations

mounded bullet,

Checking for water through sampling at the wagon,

TSV may pop out may leak (3/4"

OUTLET)

Low

Temperature

Leakage valves/cracked pipelines same as for high pressure from Ice formation, exposure to workers will cause cold burn

Maintenance

Corrosion

Poor ROV maintenance Delay in closing and more leak of LPG in the open

As per regulatory requirements

PRV maintenance

HLA maintenance

Malfunction during over pressurization

Overfull

As per regulatory requirements

Two independent gauges are available - servo gauge &

Rochester gauge As per regulatory requirements

More corrosion Presence of corrosive materials (traces of

H2S, NaOH)

Can cause internal corrosion of the pipeline

Corrosion allowance has been provided in the pipeline thickness in the design.

Schedule for hydro pressure

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Remarks

Check from manufacturer?

SA 106 Gr B Schedule

40

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Parameter Deviation Cause Consequences Safeguards

testing available.

Recommendations Remarks

Ambient condition, proximity to excessive underground moisture

Can cause external corrosion of the pipeline Slow rate of corrosion affects integrity of pipe over time

All above ground pipelines are painted with 180 micron thick anti corrosive paint coat.

Underground segments are coated with …… coat.

Due to internal corrosion from water

Internal corrosion affect pipe integrity over time

Water is removed from the wagon & mounded bullet

Utilities

Loss of power Loss of electricity supply - ROV fails close, Compressor trips, condition no flow

Flow may continue to the BPCL tanks due to vapour pressure differential

Communication Loss of communication

Hardware failure/battery failure

Over filling of the storage tank beyond safety limit

Operator monitoring & backup power available nil

Valve can be closed at the storage tank. Level monitored from the Control Room.

Automatic tank gauging (ATG) system has High level and Low level trip.

Alternate mode of communication may be considered

Intrinsically safe communication/ mobiles may be provided

Walkie talkie, pager to be provided at the gantry

Wrong communication

Operator closes the valve but compressor is not stopped

Product heating

Operator error during Overfilling

Pressure & temperature gauge provided on the outlet line. of Automatic tank gauging (ATG) Training to be imparted

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HAZOP FOR PROPOSED ADDITIONAL MOUNDED BULLETS FOR STORAGE OF LPG, BPCL, CHERLAPALLI, AP

Parameter

Procedure

Deviation Cause

Unloading

Consequences

mounded bullet during loading activity

Safeguards

system has High level and Low level trip. Further, unloading is a manned operation and the unloading motor is stopped manually before the high level

(85%) is reached

Recommendations

and SOP to be strictly adhered to

Remarks

Non - adherence to standard operating procedures

Proper bonding and earthing of unloading header not done leading to accumulation of Static

Electricity

Possibility of fire/ dispersion at flanges if there is leakage

Checklist

Work permit procedure

Periodic electrical audit

Improper procedure followed during checking the water content in LPG wagon

Water enters the LPG sphere, (part of unloading operation)

LPG may come out if valve of the sampling cap is accidently open

Procedure for draining of bullet is available

Check for formation of explosive mixture

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