QUANTITATIVE RISK ASSESSMENT...

QUANTITATIVE RISK ASSESSMENT REPORT FOR

LNG UNLOADING, STORAGE & RE-GASIFICATION PLANT AT

KRISHNAPATNAM PORT, ANDHRA PRADESH

Submitted to:

LNG BHARAT PRIVATE LIMITED

Andhra Pradesh

Submitted by:

Vimta Labs Ltd.

142 IDA, Phase-II, Cherlapally Hyderabad–500 051, Telangana State

[email protected], www.vimta.com (NABET & QCI Accredited, NABL Accredited and ISO 17025 Certified Laboratory,

Recognized by MoEF, New Delhi)

October 2015

LNG Bharat Pvt. Ltd.

Quantitative Risk Assessment (QRA) for LNG Storage & Re-Gasification Terminal at Krishnapatnam Port,

Andhra Pradesh

Revision: A2 Oct 2015

VIMTA Labs Limited, Hyderabad 2

1.0 INTRODUCTION

LNG Bharat Pvt. Ltd. (LNGBL), is a subsidiary company of KEI-RSOS Petroleum &

Energy (KRPEL) based in Rajahmundry, East Godavari, Andhra Pradesh. LNGBL

plans to set up India’s first floating storage LNG import terminal at

Krishnapatnam Port near Nellore in AP. The on-shore facilities will include a LNG

storage tanks, pumps, trailer filling stations, re-gasification system to supply

natural gas to pipeline. The facility will have a capacity of 5.0 MMTPA of LNG.

The LNGBL project is implemented by participation of INOX India limited, a

globally acclaimed company offering comprehensive solutions in cryogenic

storage, vaporization and distribution engineering. INOX India recently picked up

majority stake in Cryogenic Vessel Alternatives (CVA), a world leader in large

cryogenic transport tanks, oil and gas field pumping units, and mobile LIN storage

units. With this acquisition, INOX India has become the second largest player in

this business across the world.

The environmental impact assessment studies for the LNGBL project are being

carried out by Vimta Labs Limited, Hyderabad.

As per the Terms of Reference (ToR) issued by Expert Appraisal Committee,

Ministry of Environment & Forests, Government of India for this project, a tisk

assessment study is to be carried out in order to identify the hazards in the

facility and ensue that necessary protective measures are provided.

Accordingly, this quantitative risk assessment (QRA) study for the proposed LNG

import, storage and re-gasification facilities of LNG Bharatwas carried out by

QCI/NABET accredited Functional Area Expert (Risk & Hazard) of Vimta Labs in

consultation with team members from INOXCVA and LNGBL.

2.0 FACILITY DESCRIPTION

The system consists of LNG unloading, storage, transfer, vaporization & supply

of natural gas to users.

A floating storage unit (FSU) shall be parked on the jetty in KPT port which

shall store approx. 1,30,000 m3 of LNG. It shall deliver LNG at about 600

m3/hr. and at 5 barg at inlet of flexible hose connecting the FSU to jetty. The

FSU shall also deliver 2,00,000 Nm3/day of boil of gas at 1 barg and 5 deg. C

temperature at inlet of flexible hose connecting the FSU to jetty. The boil off

and LNG shall be brought to shore for storage and use.

Unloading arms shall be used to transfer LNG from FSU to ground valve unit.

The valve unit is connected by insulated pipe line to the land based storage

facility which is about 2500 metres away. The main LNG pipeline shall be 36”

NB size and shall be cold insulated. The BOG pipeline shall be 12”size. Other

pipelines such as LNG recirculation, nitrogen gas and fire water shall also be

configured.

The storage facility at KPT shall be configured in two phases. Phase 1 shall

consist of three horizontal vacuum insulated cryogenic storage tanks with total

gross capacity of 1050 m3. LNG unloaded from FSU shall be filled in these

storage tanks. When the FSU pumps are not operating, the long LNG pipeline

needs to be kept in cold condition. To achieve this, two separate pumps of

approx. 36 m3/hr each, located near the storage tank shall be provided. The



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pumps shall circulate LNG in the long pipeline to keep in under cold condition. A

separate 3” or 4” recirculation line is provided for this purpose. The storage

facility has provision of 8 tanker filling bays. The LNG shall be filled from

storage tanks into trailers parked in these bays by pressure transfer. Provision

exists to fill trailers in case of emergency by using the re-circulation pumps

also. Each bay has a weigh bridge to measure and control the quantity of LNG

filled.

The FSU generates significant amount of BOG approx. 2,00,000 Nm3/day (8350

Nm3/hr). A separate BOG compressor shall be configured in the storage area to

further compress this BOG and deliver into user gas pipeline at 10 bar (g) and

2,00,000 Nm3/day flow rate. All the 3 gas lines meet in a common header from

where the natural gas shall be delivered to the 24” pipeline through metering

system. During the un-loading of ship BOG generated may reduce. To

compensate the same two additional pumps (max. 8000 Nm3/hr) are provided

which shall pump liquid from storage tanks (350 m3 X 3 Nos.) and add to the

gas flow in the main line. Ambient vaporizers shall be used to gasify this make-

up stream of LNG. The gas shall be supplied into 24” main gas line grid.

The BOG from semi-trailers & storage tanks shall be collected and feed to BOG

compressor located in storage area.

Phase 1A shall consist of a full containment type tank of 30,000 m3 to receive

and storage LNG. Submerged pumps inside the tank of suitable capacity shall

be provided to pump liquid out and required pressure 15 barg and flow rate

20,00,000 Nm3/day. Suitable re-gas arrangement shall be provided consisting

of ambient air vaporizers. Regulation and metering scheme shall be provided.

The gas shall be supplied into 24” main gas line grid.

Phase 2 shall consist of additional three full containment type tanks of 30,000

m3 capacity to receive and storage LNG. Submerged pumps inside the tank of

suitable capacity shall be provided to pump liquid out and required pressure 15

barg. Booster pumps will increase the pressure to about 70 barg. Suitable re-

gas arrangement shall be provided consisting of ambient air vaporizers.

Regulation and metering scheme shall be provided. Each of the three sets of

pumps, vaporizers and metering system will have capacity to supply 4

MMSCMD of gas at 65 barg pressure to the main gas line grid.

The facility shall also have liquid nitrogen (LN 2) storage system (approx. 10

kL) for supply of gaseous nitrogen (GN 2) as utility to ensure safety in

operation and maintenance of the LNG plant.

Following is a list of the equipment’s which form a part of the LNG Plant:

Phase – 1

1. Three horizontal vacuum insulated cryogenic storage tanks each with 350

m3 gross capacity (Model HL 35007 E)

2. Two Cryogenic liquid transfer pumps for recirculation and (or) trailer filling

3. Two Cryogenic liquid transfer pumps for grid line feed

4. Ambient air vaporizer for BOG generated from the storage tanks (AVC 3000

HP, 1 nos.)

5. Ambient air vaporizers for gas make-up to the grid line (AVC 2400 HP, there

shall be two banks of 4 vaporizers (one bank shall be working & another

stand-by)



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6. Valve skid for filling of storage tanks and trailers

7. BOG compressor for BOG generated from storage tanks & FSU, trailers

8. Pressure regulation & metering (3 no & 1 no. respectively)

9. Valve skid for trailer filling & BOG

10. Skid for trailer depressurization

11. Drain vessel

12. Suction accumulator if required.

13. Valve skid on the jetty

14. Liquid nitrogen storage tank, ambient air vaporizer, pressure regulator for

GN2 supply

Phase – 1A

1. Flat bottom tank of full containment type, capacity 30000 m3 – 1 No.

2. Vaporizing skids (Capacity 2000000 Nm3/day, 83000 Nm3/Hr)

3. Pressure regulation & metering skid

4. BOG compressor for BOG generated from FBT

Phase – 2

1. Flat bottom tank of full containment type, capacity 30000 m3 – 3 Nos.

2. Tank pumps and high pressure (HP) pumps

3. Vaporizing skids (Capacity 4 MMSCMD)

4. Pressure regulation & metering skid

5. BOG compressor for BOG generated from FBT

Layout diagram of the proposed LNG Terminal at Krishnapatnam Port is shown

in Figure-1.

The arrangement for LNG supply from FSU is shown in Figure-2.



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FIGURE-1

LAYOUT OF LNG BHARAT TERMINAL AT KRISHNAPATNAM PORT



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FIGURE-2

ARRANGEMENT FOR LNG SUPPLY FROM FSU



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3.0 SCOPE, OBJECTIVE & METHODOLOGY

3.1. Scope

The scope of this QRA study covers the LNG storage and re-gasification plant of

LNG Bharat Private Limited including facilities under Phase 1, Phase 1A and

Phase-2 with 5 MMTPA capacity located in Krishnapatnam Port area.

3.2 Objective

The objectives of this study are as follows:

Identify major accident scenarios associated with the storage and handling of

hydrocarbons in the LNG terminal

Carry out consequence analysis for the significant accident scenarios

Carry out quantitative risk analysis,

Compare the risk values with specified risk tolerance criteria and

Identify measures for risk reduction wherever warranted.

3.3 Methodology

Risk arises from hazards. Risk is defined as the product of severity of

consequence and likelihood of occurrence. Risk may be to people, environment,

assets or business reputation. This study is specifically concerned with risk of

serious injury or fatality to people due to process hazards related to storage and

handling of LNG.

The following steps are involved in Quantitative Risk Assessment:

Study of the plant facilities and systems.

Identification of the hazards.

Enumeration of the failure incidents.

Estimation of the consequences for the selected failure incidents.

Risk analysis taking into account the failure frequency, extent of

consequences and exposure of people to the hazards.

Risk assessment to compare the calculated risk level with risk tolerability

criteria and review of the risk management system to ensure that the risk is

“As Low As Reasonably Practicable” (ALARP)

The process of QRA is shown in the following block diagram in Figure 3.



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FIGURE-3

FLOW DIAGRAM OF QUANTITATIVE RISK ASSESSMENT (QRA)

3.3.1 Consequence Analysis

Consequence analysis for the selected failure scenarios is carried out using DNV

Phast software which provides results for selected failure scenarios such as the

following:

Dispersion of toxic clouds to defined concentrations

Heat radiation intensity due to pool fire and jet fire

Explosion overpressure

Phast stands for ‘Process Hazard Analysis Software Tool’. It uses Unified

Dispersion Modeling (UDM) to calculate the results of the release of material into

the atmosphere.

Phast has extensive material database and provides for definition of mixtures.

Phast software is well validated and extensively used internationally for

consequence and risk analysis.



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3.3.2 Quantitative Risk Analysis (QRA)

The Quantitative Risk Analysis (QRA) is carried out using the renowned DNV

software Phast Risk Micro (previously known as SAFETI Micro) version 6.6.

The following input data are required for the risk calculation:

Process data for release scenarios (material, inventory, pressure,

temperature, type of release, leak size, location, etc.)

Estimated frequency of each failure case

Distribution of wind speed and direction (wind rose data).

Distribution of personnel/ population in the plant/ adjoining area during

the day and night time.

Ignition sources

Failure frequencies are estimated using generic failure databases published by

organizations such as International Association of Oil & Gas Producers (OGP).

RISK ANALYSIS

The results of Quantitative Risk Analysis are commonly represented by the

following parameters:

Individual Risk

Societal Risk

Individual risk is the risk that an individual remaining at a particular spot would

face from the plant facility. The calculation of individual risk at a geographical

location in and around a plant assumes that the contributions of all incident

outcome cases are additive. Thus, the total individual risk at each point is equal

to the sum of the individual risks, at that point, of all incident outcome cases

associated with the plant.

The individual risk value is a frequency of fatality, usually chances per million per

year, and it is displayed as a two-dimensional plot over a locality plan as contours

of equal risk in the form of iso-risk contours as shown in the following Figure-4.

FIGURE-4

ISO-RISK CONTOURS ON SITE PLAN (TYPICAL)



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3.3.3 Risk Tolerability Criteria

For the purpose of effective risk assessment, it is necessary to have established

criteria for tolerable risk. The risk tolerability criteria defined by UK Health &

Safety Executive (UK-HSE) are normally used for risk assessment in the absence

of specific guidelines by Indian authorities.

UK-HSE has, in the publications “Reducing Risk and Protecting People” and

“Guidance on ALARP decisions in control of major accident hazards (COMAH)”

enunciated the tolerability criteria for individual risk .

Indian Standard IS 15656:2006 provides guidelines for hazard identification and

risk analysis.

The risk tolerability criteria are as follows-

An individual risk of death of one in a million (1 x 10-6) per annum for

both workers and the public corresponds to a very low level of risk and should

be used as a guideline for the boundary between the broadly acceptable and

tolerable regions.

An individual risk of death of one in a thousand (1 x 10-3) per annum

should on its own represent the dividing line between what could be just

tolerable for any substantial category of workers for any large part of a

working life, and what is unacceptable.

For members of the public who have a risk imposed on them ‘in the wider

interest of society’ this limit is judged to be an order of magnitude lower, at 1

in 10,000 (1 x 10-4) per annum.

The upper limit of tolerable risk to public, 1 x 10-4 per year, is in the range of risk

due to transport accidents. The upper limit of broadly acceptable risk, 1 x 10-6 per

year, is in the range of risk due to natural hazard such as lightning. The

tolerability criteria for individual risk are shown in Figure 5.



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Intolerable Risk

Risk Tolerable If ALARP

Broadly Acceptable

10-3 per year

10-6 per year

10-4 per year

10-6 per year

Risk to Personnel Risk to Public

FIGURE-5

INDIVIDUAL RISK CRITERIA

3.3.4 Societal Risk (or Group Risk) Criteria

Societal Risk parameter considers the number of people who might be affected by

hazardous incidents. Societal risk is represented as an F-N (frequency-number)

curve, which is a logarithmic plot of cumulative frequency (F) at which events

with N or more fatalities may occur, against N.

Societal risk criteria indicate reduced tolerance to events involving multiple

fatalities. For example a hazard may have an acceptable level of risk for one

fatality, but may be at an unacceptable level for 10 fatalities. The tolerability

criteria for societal risk as defined by UK-HSE are shown in the following Figure-

6.



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FIGURE-6

SOCIETAL RISK CRITERIA

3.3.5 Risk Assessment

Based on the results of QRA, necessary measures to reduce the risk to ALARP are

to be formulated. For this purpose the information regarding top risk contributors

provided by Phast Risk software is useful.



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4.0 QUANTITATIVE RISK ANALYSIS

4.1 Input Data for Risk Analysis

The details of storage tanks are provided in Table-1.

TABLE-1

DETAILS OF STORAGE TANKS

S.no. Description Nos. Pressure Temp. (c) Type Capacity (each)

Phase-1

1. LNG Tanks

(T101/102/103)

3 3.2 barg Horizontal;

Vacuum insulated

350 M3

Phase-1A

2. LNG Tank (ST1001) 1 138 mbarg (-)162 Full containment 30,000 MT

Phase-2

4. LNG Tanks (ST1001A; ST1001B; ST1001C)

3 138 mbarg (-)162 Full containment 30,000 MT

4.2 Weather Data

The weather data for the site required for dispersion analysis and QRA are

provided in Table-2.

TABLE-2

CLIMATOLOGICAL DATA

Month Temperature (0C) Rainfall (mm)

Max. Min. Monthly Total

January 28.2 20.4 4

February 30.6 20.8 0

March 39.6 22.8 0

April 38.4 24.2 0

May 41.7 24.7 18

June 40.0 22.0 174

July 38.0 22.0 38

August 37.0 23.0 160

September 39.7 25.2 192

October 35.4 24.2 257

November 34.8 22.6 158

December 28.7 21.5 159

Wind rose diagrams for the site showing the distribution of wind direction and

wind speed during a year are shown in the Figure-7.



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FIGURE -7

WIND ROSE DIAGRAM

Annual

8.30 hr

Annual

17.30 hr

SPEED CALM

1151

SCALE

19 >19 Km/hr

5%

4.0%

SW

10.5% N

W

5.7

% S

9.8% W C-16.2%

SE 7.0%

E 1.1%

NE 2.

6%

N 1

.4%

4.4

% N

NW

NNE 1

.1%

3.1

% S

SW

SSE 9

.3%

9.9% WSW

11.0% WNW

ESE 1.7%

ENE 1.2%

2.0%

SW

2.0% N

W

0.4

% S

7.1% W C-3.9%

SE 12.3%

E 11.0%

NE 13

.3%

N 0

.5%

1.0

% N

NW

NNE 3

.7%

0.5

% S

SW

SSE 2

.9%

5.1% WSW

4.6% WNW

ESE 17.5%

ENE 12.2%



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4.3 Hazards in LNG Installation

LNG is liquefies natural gas. It is mostly methane with some ethane and propane

depending on the source.

The properties of LNG significant for this study are as follows.

Molecular weight 16-17 (approx.)

Normal boiling point (-) 162 C

Liquid density at boiling point 430 kg/m3

Vapour density at 20 C 0.7 kg/m3

Lower flammable limit (LFL) 5 % (vol)

Upper flammable limit (UFL) 15 % (vol)

Reactivity classification for explosion Low

Accidental release of LNG can result in the following hazards.

Pool fire due to burning of liquid LNG causing burn injury and structural

damage by thermal radiation

Jet fire due to burning of gas leaking from pressurized equipment or piping

Flash fire due to ignition of flammable gas cloud causing burn injury

Vapour cloud explosion due to ignition of large flammable gas cloud under

conditions of confinement or congestion

Explosion effect due to rapid phase transformation (RPT) by evaporation of

large quantity of LNG released into water

Roll over phenomenon in storage tank due to sudden vaporization of large

quantity of LNG under abnormal conditions

Asphyxiation hazard due to dispersion of large quantity of gas reducing

oxygen concentration in the vicinity

Cold burns due to contact with cryogenic liquid

Pool Fire, Jet Fire & Flash Fire

The main hazard of LNG spill is fire and primary focus is on pool fire caused by

ignition of vapour formed on a pool of liquid formed by the spill. LNG being mainly

methane, burns with a luminous non-smoky flame and the pool fire has high

radiation intensity than heavier hydrocarbons. A large LNG pool fire is shown

below. (Ref: LNG Risk Based Safety – Modeling and Consequence Analysis by

Woodward & Pitblado).

Jet fire is caused by release by leak from pressurized vessel or piping, such as

natural gas system after vaporizer. The heat radiation from jet fire is localized

and likely to cause damage of structures and equipment if prolonged.



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When LNG spills on water or land, gas evaporating from the pool will mix with air

and form a vapour cloud which will then be driven by the wind. If any point of the

vapour cloud with dimensions defined to flammable concentrations (above lower

flammable limit) reaches an ignition source and ignites, there will be a flash fire.

The flash fire will be transient, with exposure lasting only for fraction of a second.

It will cause serious burn injury to people only inside the fire zone. The flash fire

will quickly burn back to the source and, in this case, result in a pool fire.

Vapour Cloud Explosion

Ignition of the vapour cloud having large quantity of fuel gas mixed with air to

flammable concentration (above LFL) may also result in vapour cloud explosion

(VCE) under conditions of partial confinement or congestion. A pressure wave is

formed by the flame front and the resultant overpressure may cause damage to

people and structures. The extent of explosion overpressure depends on the

flame speed. Natural gas has low reactivity of explosion. Therefore, vapour cloud

explosion is not likely in case of LNG release in open area.

Rapid Phase Transformation (RPT)

RPT explosion is a physical explosion due to sudden boiling from liquid to vapour

that occurs when LNG is spilled into water such that LNG penetrates into and

mixes well with water. No injuries have occurred from RPT of LNG but equipment

damage may occur.

Roll Over in LNG Tank

Liquid in LNG tank kept stagnant for long period can stratify. Liquid density in

upper layer will increase over time due to methane boiling off thus increasing the

percentage of heavier components. When at some point the layers invert, the

lower layer will rise to the surface and a fraction of it immediately flash. Since

one volume of liquid will expand to 600 volumes of vapour, there will be sudden

increase in tank pressure that may exceed relief capacity. This phenomenon is

known as Roll Over. It is a hazard to operating personnel. Preventive measures

for roll over include provision of multiple temperature indicators to monitor

temperatures in different zones of the tank and recirculation of tank contents to

avoid stagnation.

Asphyxiation

When vapour from leaking LNG mix with air, oxygen concentration in air

(normally 21 %) will be reduced. Atmosphere with less than 19.5% oxygen is

designated as oxygen deficient. Breathing air with oxygen concentration below

15% will impair behaviour, below 10% will cause nausea and vomiting and below

6% will cause fatality. Such asphyxiation effect will only very close to the LNG

spill and thus not expected to affect the public.

Cold Burn

Accidental contact with leaking LNG at (-) 162 C will cause severe cold (frost)

burn injury. There was one incident in 1977 during ship loading when a large

valve made of wrong grade of aluminium ruptured spraying LNG on the worker

nearby. This hazard is likely to occur close to the leak. Preventive measures

include use of proper materials for equipment, leak check procedure and use of

appropriate clothing and PPE.

4.4 LNG Incidents

LNG industry has maintained high standards of safety over the past six decades.

Safety record of all LNG facilities worldwide demonstrate safety of the primary



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containment of LNG tank because the secondary spill containment systems

installed around all the tanks have never been required to hold liquid.

A few significant incidents in LNG installations available in technical publications

are as follows.

Cleveland, Ohio (1944)

A large LNG tank failed shortly after it was placed in service. Ignition of the

dispersing vapour cloud resulted in 128 fatalities in nearby residential area. The

tank failure was due to compromise in the material of construction on account of

war time shortage of alloy steel. This is the only incident of LNG tank failure.

Italy (1971)

This was one incident of roll over while unloading into LNG tank. The tank

pressure increased suddenly and roof was slightly damaged. There was no

ignition.

Maryland (1979)

Explosion occurred in the electrical substation of LNG terminal due to leakage

through inadequately tightened electrical penetration seal of LNG pump. The

explosion caused one fatality, injury to another and considerable property

damage. Necessary changes were made in design codes to prevent such

incidents.

Indonesia (1993)

LNG leaked from an open run-down line in the LNG liquefaction facility during

pipeline modification project and entered the concrete storm water system. It

caused rapid vapor expansion which overpressurized and ruptured the sewer

lines.

Ship Incidents

There were a few incidents of LNG release due to valve leakage and two incidents

of overfilling which resulted in cracking of deck plates. In one case of valve

failure, there was spillage of LNG on the worker.

There were a few cases on stranding/ grounding of vessel resulting in damage of

ballast tanks and vessel bottom, and listing of vessel. However, there were no

instances of LNG release.

There was one case of mooring breakage during loading resulting in hull and deck

fractures. However, there was no LNG release.

There was one case of collision of LNG carrier in ballast condition with US nuclear

powered submarine. The ship suffered leakage of sea water into double bottom

dry tank area.

Damage of LNG tank in ship can occur only when the hulls are breached by high

energy collisions. This is not likely in the area around LNG berth in a port where

the carrier movement is carried out under controlled conditions using velocity

meters and other devices. Regular maintenance of shipping channel and control

of ship movement in port is required to prevent occurrences of collision or

grounding.

4.5 References

The following publications are used for reference in this study.

“LNG Risk Based Safety – Modeling and Consequence Analysis” by Wodward &

Pitblado, American Institute of Chemical Engineers

“LNG Safety and Security” by Center for Energy Economics, Texas

“NFPA 59A: Standard for the Production, Storage and Handling of Liquefied

Natural Gas – 2013 Edition”



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“EN 1473:2007 – Installation and equipment for liquefied natural gas – Design

of onshore installations”

“ EN 14620:2006 - Design and manufacture of site built, vertical, cylindrical,

flat-bottomed steel tanks for storage of refirigated liquefied gases with

operating temperature between 0C and -165C” (This standard replaces BS

7777)

“Risk-Based LNG Facility Siting and Safety Analysis in the U.S. – Recent

Developments” by American Gas Association

4.6 Consequence Analysis

In case of leaks from the LNG tanks, pumps, vaporizers etc. the hazards are

mainly pool fire, jet fire, flash fire and/or vapour cloud explosion.

Pool/ jet fire heat radiation

The effects of heat radiation from pool fire are shown in the following Table-3.

TABLE-3

EFFECTS OF HEAT RADIATION

Heat Radiation Level

(kW/m2) Observed Effect

1.2 Average solar radiation received at noon in summer

4 Sufficient to cause pain to personnel if unable to reach cover within 20 seconds; however blistering of the skin (second-degree burn) is likely; 0% lethality.

12.5 Minimum energy required for piloted ignition of wood, melting of plastic tubing.

Significant chance of fatality for medium duration exposure

37.5 Sufficient to cause damage to process equipment. Significant chance of fatality if exposed even for very short duration.

Vapour Cloud Explosion (VCE)

When a large quantity of flammable vapour or gas is released, mixes with air to

produce sufficient mass in the flammable range and is ignited, the result is a

vapour cloud explosion (VCE). The damage effect of VCE is due to overpressure,

The effects of overpressure due to VCE are shown in the following Table-4.

TABLE-4

EFFECTS OF OVERPRESSURE

Over-pressure

Observed Effect bar(g) psig

0.021 0.3 “Safe distance” (no serious damage below this value);

some damage to house ceilings; 10% of window glass

broken.

0.069 1 Repairable damage; partial demolition of houses, made

uninhabitable; steel frame of clad building slightly

distorted.

0.138 2 Partial collapse of walls of houses.

0.207 3 Heavy machines (3000 lb) in industrial buildings

suffered little damage; steel frame building distorted

and pulled away from foundations.



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Flash fire is represented by presence of flammable gas mixture above LFL

concentration.

Consequence analysis has been carried out for selected scenarios in the LNG

Terminal using DNV Phast software.

Results of consequence analysis for the above scenarios are shown in the Table-

5.

TABLE-5

CONSEQUENCE ANALYSIS RESULTS

Description Downwind Effect

Distances (Metres)

Wind speed & Atm. Stability Class 3 m/s; D 6 m/s; D

1. LNG Vaporizer Inlet - 25mm Leak (Liquid)

Pool fire heat radiation intensity

4 kW/m2 117 117

12.5 KW/m2 73 74

37.5 kW/m2 43 45

Vapour cloud explosion overpressure

0.021 bar (0.3 psi) 151 140

0.069 bar (1 psi) 109 97

0.207 bar (3psi) 94 78

Flash fire envelope

LFL concentration (4.4%) 85 70

2. LNG Vaporizer Outlet - 25mm Leak (Gas)

Jet fire heat radiation intensity

4 kW/m2 39 39

12.5 KW/m2 31 32

37.5 kW/m2 25 26


0.021 bar (0.3 psi) 56 48

0.069 bar (1 psi) 35 29

0.207 bar (3psi) 28 24

Flash fire envelope


3. FSU Discharge Connection Hose Leak


4 kW/m2 67 68

12.5 KW/m2 42 44

37.5 kW/m2 24 26


0.021 bar (0.3 psi) 124 92

0.069 bar (1 psi) 80 55

0.207 bar (3psi) 64 42

Flash fire envelope


4. Ship to Ship Transfer Hose Leak


4 kW/m2 92 94

12.5 KW/m2 58 60

37.5 kW/m2 33 36


0.021 bar (0.3 psi) 135 103

0.069 bar (1 psi) 85 65

0.207 bar (3psi) 67 52

Flash fire envelope




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The LNG bullets to be installed in Phase – I are double wall type with vacuum insulation

in the annular space. This type of vessel is not susceptible to BLEVE/ fire ball hazard.

The large LNG tanks to be installed in Phase – IA and Phase – II are full containment

type with pre-stressed outer wall and RCC roof which are designed to contain the liquid

and vapour without any limitation. Therefore, pool fire and gas dispersion due to failure

of primary containment (inner steel tank are not considered for these tanks.

Graphical results of consequence analysis plotted on pipeline route map are provided in

the Figure-8 to Figure-19.



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FIGURE-8

LNG VAPORIZER 1 INLET LIQUID LEAK

(Pool Fire Intensity Ellipse-3 m/s; D)



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FIGURE-9

LNG VAPORIZER 1 LIQUID LEAK

(Flash Fire Envelope - 3 m/s; D)



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FIGURE-10

LNG VAPORIZER 1 LIQUID LEAK

(Vapour Cloud Explosion Overpressure Radii -3 m/s; D)



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FIGURE-11

LNG VAPORIZER 2A INLET LIQUID LEAK

(Pool Fire Intensity Ellipse-3 m/s; D)



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FIGURE-12


(Flash Fire Envelope-3 m/s; D)



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FIGURE-13


(Vapour Cloud Explosion Overpressure Radii -3 m/s; D)



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FIGURE-14

FSU DISCHARGE HOSE LEAK

Pool Fire Intensity Ellipse - 3 m/s; D



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FIGURE-15

FSU Discharge Hose Leak

Flash Fire Envelope- 3 m/s; D



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FIGURE-16

FSU DISCHARGE HOSE LEAK

Vapour Cloud Explosion Overpressure Radii-3 m/s; D



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FIGURE-17

LNG SHIP TO SHIP TRANSFER HOSE LEAK

Pool Fire Intensity Ellipse -3 m/s; D



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FIGURE-18


Flash Fire Envelope- 3 m/s; D



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FIGURE-19


(Vapour Cloud Explosion Overpressure Radii-3 m/s; D)

Review of Consequence Analysis Results

The following observations are made based on review of the results of

consequence analysis for the selected failure scenarios.

High pressure LNG liquid and vapour leak from Vaporizer

The fire radiation and gas dispersion effects fall well within the facility boundary.

FSU discharge hose leak

The pool fire radiation, gas dispersion and vapour cloud explosion overpressure

effects fall within the safety exclusion circle (200 m radius) indicated in the layout

plan.

It is noted that FSU will not be required after implementation of Phase-II. In the

subsequent system for transfer directly from LNG carrier, it is recommended to

provide unloading arms.

Ship to ship transfer hose leak

The pool fire radiation, gas dispersion and vapour cloud explosion overpressure

effects fall within the safety exclusion circle (200 m radius) indicated in the layout

plan.



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4.7 Input Data for QRA

The input data for all failure scenarios considered for QRA are listed in Table-6.

TABLE-6

FAILURE SCENARIOS AND THE RELEVANT INPUT DATA

Item Description Dyke Size Failure

Scenario

Failure Rate for

Each Equipment (per year)

LNG Tanks (Vacuum Insulated) –

350 M3 Capacity

(T101/102/103)

5 mm Leak 1.0E-03

25 mm Leak 4.0E-04

100 mm Leak 1.0E-04

LNG Tank (Full Containment

Type) – 30,000 M3 Capacity

(ST1001; ST1001A; ST1001B;

ST1001C)

120 x 120

x 2.5 m

Catastrophic

failure

1.0E-08

Outlet Pipe

Failure

1.0E-05

LNG Vaporizer Unit E1301A/1302A;

E1301B/1302B; E1301C/1302C)

5 mm Leak 7.0E-04

25 mm Leak 2.5E-04

100 mm Leak 1.0E-04

LNG Trasfer System to/from FSU

Hose/ flange connections

5 mm Leak 2.0E-05

25 mm Leak 5.0E-06

100 mm Leak 6.0E-07

4.8 Population Data

The distribution of people in the LNG Terminal and surrounding area is as follows.

Total number of people within the port area after the completion of all phases of

the port operation will be around 4000.

The number of persons within the LNGBL is estimated to be about 130 including

the contractor persons

4.9 Ignition Source Data

The LNG terminal and adjacent POL storage area are to be maintained free of

ignition sources and provided with flame-proof electrical equipment.

The whole port area outside the LNG terminal and POL storage has been

considered for potential ignition sources.



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4.10 QRA Results

Individual risk

Iso-risk contours for individual risk due to LNG Terminal Phase 2 are shown in

Figure-20. An enlarged diagram is shown in Figure-21.

FIGURE-20

ISO-RISK CONTOURS FOR INDIVIDUAL RISK (PHASE 2)

1E-06 per year

1E-07 per year



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FIGURE-21

ISO-RISK CONTOURS (PHASE 2) – ENLARGED VIEW

1E-06 per year

1E-07 per year



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Revision: A1 June 2015

VIMTA Labs Limited, Hyderabad

36

The maximum individual risk contour observed in the LNG Terminal is 1E-06 per

year. The maximum individual risk is found to be 2.4E-05 per year. This will be

the location-specific individual risk (LSIR) applicable to a person standing at the

site all the time in the year. However, any individual person working in the LNG

Terminal is present at the site for an average period of about 8 hours of work

during the day.

Therefore the individual-specific individual risk (ISIR) a person working in the LNG

Terminal is estimated as follows:

ISIR = LSIR x (fraction of time in the year when exposed to risk)

= (9.0E-06) x (8/24) = 3E-06 per year.

The estimated maximum ISIR value of 3E-06 per year is in the lower part of ALARP

region close to Acceptable level.

Risk contours of 1.1E-06 per year are within the LNG Terminal. Therefore the

individual risk to members of the public due to the LNG Terminal is less than 1.1E-

06 per year and in Acceptable region

The vales of individual risk to plant personnel and general public in comparison

with the specified risk criteria are shown in Figure 22.

FIGURE-22

INDIVIDUAL RISK DUE TO LNG TERMINAL

Intolerable Risk

10-3 per year

10-4 per year

Risk to Personnel

Risk to Public

Risk Tolerable if ALARP

Max. Individual Risk to

Plant Personnel: 3 x 10-6 per

year Max. Individual Risk to

Public: 1 x 10-7 per year

10-6 per year 10-6 per year

Broadly Acceptable

Risk



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Societal Risk

The FN Curves for societal risk due to the LNG Terminal during Phase 2 with 5 MM

TPA capacity is shown in Figure-23.

FIGURE-23

SOCIETAL RISK DUE TO LNG TERMINAL

It is seen that the societal risk due to the LNG Terminal is well within the

Acceptable region.



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5.0 CONCLUSIONS & RECOMMENDATIONS

5.1 Conclusions

The results of this QRA study for the LNG Terminal at Krishnapatnam Port lead to

the following conclusions.

Individual risk to members of the public is less than 1 x 10-6 per year and

therefore in the Acceptable level.

Individual risk to personnel working in the Terminal is 3 x 10-6 per year which

is in the lower part of ALARP region very close to Acceptable level.

Societal risk is well within the Acceptable level.

Consequence analysis for LNG release shows that for the maximum credible

scenarios such as 25 mm leak in high pressure LNG system, the effect distances

for pool/ jet fire, flash fire and VCE are within the Terminal boundary.

LNG tanks are of full containment type which ensures high degree of safety for

the LNG storage system.

The reaction time considered for closure of valves is 10 sec. The leak scenario is

for the volume of LNG contained between the valves (4 hoses). The QRA/Risk

contours are drawn accordingly for various wind directions and the envelope is

found within the 200m radius from LNGBL berth. The fire water pump house is

located outside this zone. It should be ensured that necessary safety systems

are provided to close the shutdown valves for transfer hose/ unloading arm within

10 seconds.

Based on worldwide experience over 70 years, LNG industry including on-shore

installations and marine LNG carriers has established exemplary safety record.

The above results indicate that the LNG Terminal at Krishnapatnam Port conform

well to the risk criteria. LNGBL are expected to ensure the best practices for

safety management system, engineering, construction, operation and

maintenance for the LNG Terminal.

The installation design and construction conform to relevant Indian/ international

codes and standards including OISD and PNGRB guidelines.

In case of any LNG liquid or gas leakage in the Terminal, it is necessary to isolate

the supply with minimum delay. For this purpose effective leak detection system

with alarm and automatic arrangements for isolation and/ or mitigation is to be

established. Besides the conventional systems for gas leak detection, imaging

systems are also found to be very effective for monitoring LNG transfer

equipment over large area.

Safety Measures to be adopted

Following are some of the important project specific information to be enlisted:

1) Leak detection and valve closing time is limited to 10 sec.



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2) For Hoses at ship to ship transfer a leakage scenario of 3 m3 between valves

(volume contained in 4 hoses) is considered.

3) For ship to shore transfer of LNG regular unloading arms are proposed for

improved safety against rupture/leaks as against normal hoses.

4) Double wall buffer tanks in Phase-1 and full containment tanks in Phase-1A

and Phase-2 are proposed for improved safety against tank failures.

5) Existing port DMP is being updated with project specific emergency

preparedness and risk management measures.

- - - - x - - - -



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Revision: A1 June 2015


ANNEXURE – 1

LNG TERMINAL LAYOUT DIAGRAM

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