Multi Strategy Terminal

7/27/2019 Multi Strategy Terminal

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Paper PS4-6

PS4-6.1

SAKAI LNG TERMINAL: COMPACT MULTI-STRATEGYTERMINAL BASED ON QUANTITATIVE DISASTER

RISK ASSESSMENT

Hiroshi KuwaharaDeputy Manager

Toshimitsu OkanoEngineering Center Fossil P ower Division

Kansai Electric Power Co., Inc3-22 Nakanoshima, Kita-ku

Osaka, J apan

Tetsu ShiotaPresident

Sakai LNG Corporation3-1-10 Chikko Shinmachi, Nishi-ku, Sakai-shi

Osaka, J apan

ABSTRACT

In January 2006, the Sakai LNG Terminal commenced operations as the second LNGreceiving terminal of The Kansai Electric Power Co., Inc. It is a multi-strategy terminalthat, in addition to piping fuel gas for power generation, supplies gas for industrial use tonearby factories, ships LNG by lorry and supplies LNG for hydrogen fuel production tothe largest liquid hydrogen production plant in Japan located adjacent to the terminal.Furthermore, as an LNG receiving terminal, it is one of the few facilities in the world equipped to load large class LNG tankers, which improves the LNG supply and demand

balancing capacity by fitting in perfectly with Japans power supply and demand structureand LNG procurement characteristics.

Moreover, two key features of the Sakai LNG Terminal are that it is extremely smalland located on the outskirts of a large urban area. It has the capacity to hold 420,000 m 3 of LNG and the hardware for diverse means of send-out, yet everything is neatlyconcentrated into an approximate 110,000 m 2 site in an industrial zone on the outskirts of the central city area, hence it has the smallest footprint in the world for an LNG terminal.

Because of the suburban location, the accident potential of the LNG facilities werequantitatively assessed in the planning phase of the terminal and the results were released to show the permitting authorities and local residents how safe the facilities would be.This was the first such risk assessment ever conducted on LNG facilities anywhere in theworld.


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1 BACKGROUND TO LNG TERMINAL CONSTRUCTION

Deregulation began in Japans energy markets in 2000 and, since that time, thosemarkets have become very competitive as power companies are supplying gas, gascompanies are supplying power and new players have entered both businesses. Moreover,

gas markets have grown first and foremost with hydrogen gas for fuel cell-powered vehicles.

Affront this backdrop, The Kansai Electric Power Co., Inc. built a second LNGreceiving terminal on the outskirts of an urban area of high demand density and commenced operations in January 2006 in order to ensure price competitiveness in theelectric power market and expand its revenue base by making inroads into gas markets.The events in this backdrop are outlined here following.

1.1 Deregulation of Japans Energy Markets

After the Plaza Accord of 1985, the Japanese yen rapidly appreciated, whileinternational pressure calling for deregulation and demands from domestic industries for a correction to the price difference between Japan and the rest of the world increased,which made Japans high cost structure and price correction topics of the energy industry.

In the electric power business, the Electricity Enterprises Law was twice amended in1995 and 1999, which liberalized the retailing of electric power (about 26% of all electric

power) in March 2000. This put genuine market principles to work in Japans electric power market and brought the number of competing Power Producers and Suppliers(PPS) to 23 by March 2006. Figure 1 shows the power wattage sold by PPS and their share of all sold electric power wattage. Since liberalization, figures have grown steadfastwith PPS accounting for 2.2% (of that 4.6% for extra high voltage and 0.67% for highvoltage) of all power sold in Japan as of September 2006. Also since liberalization,electricity rates have tended to decrease, showing an approximate 15% reduction in price.The scope of liberalization will reach about 60% of all electric power in April 2007 whennew amendments to the Electricity Enterprises Law go into force.

Figure 1. PPS Share of Power Sales since Retail Liberalization

0

2000

4000

6000

8000

10000

12000

2000 2001 2002 2003 2004 2005

Fiscal year

E l e c t r i c

i t y S a l e s

b y P P S ( m i l l i o n

k W h )

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

P P S s h a r e

( % )

Extra high voltage powerHigh voltage powerShare of extra high voltage powerShare of high voltage power


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PS4-6.3

Like the electric power business, retailing in the gas business was liberalized as wellin 1995 affront the growing needs for gas by industry, etc. The scope of liberalization was

broadened in 1999 to cover approximately 50% of all piped gas supply. As of March2006, there were 108 contracts being handled by 21 new entrants, such as electric power companies and trading houses, giving these new entrants about 7.6% of the supply

volume of all large volume supply.

1.2 Increased Consumption of Diverse Gases

Some 96.3% of the natural gas consumed in Japan is imported from overseas as LNG.A large portion of that is used as fuel for power generation and city gas. In the ten yearsfrom 1995, the supply of natural gas has increased about 1.3 times (Fig.2). Moreover,looking at sales volume by use of city gas, industrial consumption grew markedly, or about 1.9 times, over the ten year period from 1995 because of the rapid increase in theintroduction of natural gas by high demand users, technological progress made with gasutilization equipment in recent years and demands for action against globalenvironmental problems.

Figure 2. Trends in Sales of Town Gas by Sector

Though most of the increased consumption in natural gas is fed with imports, Japanhas for some time been producing air separated gases such as liquid nitrogen and liquid oxygen using the cold heat of LNG. Sales of these gases have steadily increased owing tothe favorable situation in industrial fields where these gases are consumed. Moreover, therapid progress of fuel cell technology in recent years is expected to spur large futureincreases in the use of hydrogen gas that is obtained in the reforming of LNG, particularlyin and around vehicle applications (Table.1).

Table 1. Fuel Cell Development Targets in Japan

2010 2020 2030

Fuel cell vehicles(Number) Approx. 50,000 Approx. 5 million Approx. 15 million

Estimated hydrogendemand (t/year) Approx. 36,000 Approx. 580,000 Approx. 1.51 million

0

200

400

600

800

1,000

1,200

1,400

1965 1970 1975 1980 1985 1990 1995 2000

Fiscal Year

T o w n

G a s

S a l e s

1 0

1 5 J

OthersIndustrialCommercialResidential


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PS4-6.4

1.3 Act ivi ties of Kansai Electri c Power

Figure 3 gives an overview of Kasai Electric Power. In preparation for theaforementioned liberalization of Japans energy markets, Kansai Electric Power launched activities to reduce costs in its electric utility business and built facilities at its Himeji

LNG Terminal to start gas consignment and ship LNG by lorry in order to increase salesof its gas business (Fig.4).

The Sakai LNG Terminal introduced here was newly built affront a backdrop of bigchanges in the economic environment in order to strengthen the companys costcompetitiveness of the electric utility business and establish a strategic comprehensiveenergy base for getting into the gas business. It was located in the vicinity of twothermoelectric power plants in an industrial zone of high energy demand density on theoutskirts of a large urban area, and was built not only to pipe gas to these power plants

but also to provide diverse means of gas send-out, hence enabling multiple businessstrategies.

Figure 3. Overview of Kansai Electric Power

Figure 4. Gas Sales of Kansai Electric Power

The Kansai RegionThe Kansai RegionServices Area: 30,000kmServices Area: 30,000km 22

Population: 20 millionPopulation: 20 million

JapanJapan

TokyoTokyo

OsakaOsaka

Kansai Electric Power (FY 2005)Kansai Electric Power (FY 2005)Installed Plant Capacity : 41,750 MWInstalled Plant Capacity : 41,750 MWPower Generation : 152.2 billion kWhPower Generation : 152.2 billion kWh

Nuclear 46%

Fossil44%

Hydro10%

LNG17%

Oil7%

IndonesiaIndonesia AustraliaAustralia MalaysiaMalaysia QatarQatar

Coal20%

4.45 million tons/year4.45 million tons/year(67% of all fossil fuels)(67% of all fossil fuels)

The Kansai RegionThe Kansai RegionServices Area: 30,000kmServices Area: 30,000km 22

Population: 20 millionPopulation: 20 million

JapanJapan

TokyoTokyo

OsakaOsaka

Kansai Electric Power (FY 2005)Kansai Electric Power (FY 2005)Installed Plant Capacity : 41,750 MWInstalled Plant Capacity : 41,750 MWPower Generation : 152.2 billion kWhPower Generation : 152.2 billion kWh

Nuclear 46%

Fossil44%

Hydro10%

LNG17%

Oil7%

IndonesiaIndonesia AustraliaAustralia MalaysiaMalaysia QatarQatar

Coal20%

4.45 million tons/year4.45 million tons/year(67% of all fossil fuels)(67% of all fossil fuels)

2 7

180 210

400

530

0

100

200

300

400

500

600

2000 2001 2002 2003 2004 2005

Fiscal Year

G a s

S a l e s

( 1 , 0

0 0 t o n )


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PS4-6.5

2 OVERVIEW OF THE SAKAI LNG TERMINAL

The biggest features of the Sakai LNG Terminal is that it is a multi-strategy terminalcapable of delivery to diverse customers and that it is a compact terminal located on theoutskirts of a large urban area. The following overview of the terminal will rotate around

these features.

2.1 Compact Suburban Terminal

The Sakai LNG Terminal is located in an industrial zone on the outskirts of SakaiCity (approx. 830,000 population), about 3 km from residential areas (see Fig.5). It sitson an approximate 110,000 m 2 site and has an approximate annual handling capacity of 2.7 million ton between its 3 storage tanks (140,000 m 3 capacity each), vaporizers, pumpsand BOG systems. It is the world smallest class of LNG terminal owing to the rationalequipment layout that resulted from the quantitative risk assessments discussed later.

Figure 5. Map of Sakai LNG Terminal Area

2.1.1 Overview of Major Equipment. Table 2 gives specifications and quantities of major equipment at the Sakai LNG Terminal.

One of the big features is the adoption of aboveground prestressed concrete tanks for storing LNG in a way that most effective utilizes the available land. Most of the other equipment is standard for an LNG terminal.

Nanko Power Station600MW 3units

Sakai LNG Terminal

Sakaiko Power Station250MW 8units

Approx. 3 km

Nanko Power Station600MW 3units

Sakai LNG Terminal

Sakaiko Power Station250MW 8units

Approx. 3 km


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Table 2. Major Equipment of Sakai LNG Terminal

Equipment Specifications

LNG storage tanks Prestressed concrete above-ground type140,000 m 3 x 3

Vaporizers Open rack vaporizer, 135 t/h x 6

LNG pumps In-tank pump, 190 t/h x 6

Unloading arms 4,000 m3/h x 3 (for LNG)

27,000 m 3 N/h x 1 (for RG)

BOG compressors 9.4 t/h x 3

Return gas blowers 27,000 m 3 N/h x 2

Flare stack 35 t/h x 1

Vent stack 47 t/h x 1

Berth 80,000 DWT

2.1.2 Layout. Figure 6 shows where the Sakai LNG Terminal is located with respectto its surroundings and Figure 7 shows the layout of the terminal. The LNG tanks arelocated from the northern end to the eastern side of the central area. The primary

processing equipment such as LNG vaporizers and BOG compressors, and utility systemsare in the southern end of the central area, while the management offices are on thewestern side. Moreover, the LNG berth is in the southwestern quadrant of the sitesandwiched between the Sakai LNG Terminal and a public road. It is connected to theterminal via 1.7 km of pipe.

Figure 6. Map of Sakai LNG Terminal

LNG Berth

Sakai LNG Terminal

LNG Berth

Sakai LNG Terminal


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PS4-6.7

Figure 7. Sakai LNG Terminal Photo

In layout studies, legal requirements were first ensured, that is to say, required clearances between equipment, minimum distances to safety devices, etc. Equipment wassectioned into zones by function (storage, production, utilities, etc.) and connected byemergency roads. Risk assessment results verified that the effects of foreseeable accidentscould be contained within the area of the site. Table 3 gives safety codes and the actualsituation at the Sakai LNG Terminal.

Table 3. Safety Codes and Actual Distances at Sakai LNG Terminal

Criteria Code ActualconditionMinimum distance between LNGequipment and residential areas or

perimeter of industrial sites206 m Approx.2,500 m

Minimum distance between LNGequipment and site boundary 20 m Approx. 30 m

Minimum distance between LNG tanks 39 m Approx. 40 m

Minimum distance between LNGequipment and hazardous substanceequipment

20 m Approx. 30 m

Lorry Loading Dock (Under construction)

LNG Vaporizers

Ground Area: 110,000m 2Utility Facilities

BOG Compressors

Office Building

Lorry Loading Dock (Under construction)

LNG Vaporizers

Ground Area: 110,000m 2Utility Facilities

BOG Compressors

Office Building


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PS4-6.8

2.2 Multi-Strategy LNG Terminal

While its main purpose is to supply natural gas as a fuel for power generation, theSakai LNG Terminal has diverse supply capabilities as a multi-strategy terminal for dealing with liberalization in Japans energy markets and the diversification of LNGsupply. Two big features are that the terminal supplies utilities to the largest liquid hydrogen production plant in Japan located nearby, and that it has large loadinginfrastructure for ocean-going ships. Here following is an introduction to the diversesend-out functions of the Sakai LNG Terminal.

2.2.1 Gas Supply to Power Plants. The Sakai LNG Terminal supplies natural gas asa fuel for power generation to two thermoelectric power plants (see Fig. 5). Together, thetwo plants produce about 4 million kW of power.

Of these, the Sakaiko Power Plant is scheduled for refurbishing to the latest in gasturbine combined cycle power generation system from April 2009 to October 2010. Intime for this refurbishing, pressure of the gas supplied to the plant will be boosted fromthe current 1.7 MPa to about 4.5 MPa, therefore plans are to add booster pumps and gasflow control equipment. Once pressure is boosted, gas supply systems of the Sakai LNGTerminal will be divided into high pressure and low pressure systems.

2.2.2 Gas Supply to Nearby Plants and Lorry Shipping Facilities. The Sakai LNGTerminal is located in an existing industrial zone. It supplies several tens of tons of natural gas per hour to nearby chemical plants and oil refineries using an approximate 4km pipeline to the Sakaiko Power Plant and directly branching from there. Moreover, theterminal has lorry loading facilities to supply LNG to customers in areas not covered by

existing LNG lines. Since sales opened in March 2006, about 1,200 lorries have carried about 13,000 ton of LNG as of November 2006.

2.2.3 Cold/Heat Usage and Hydrogen Production. Adjacent to the Sakai LNGTerminal, Hydro Edge Company built air-separated gas production plants and the largestliquid hydrogen production plant in Japan. Sales operations started in April 2006. Asshown in Figure 8, the Sakai LNG Terminal supplies these plants with natural gas as araw material for producing hydrogen and LNG as a heat and cold source for producingair-separated gases (nitrogen, oxygen and argon). Table 4 gives specifications of major equipment operated by Hydro Edge Company.

Though other existing LNG terminals separate liquids and gases using the cold and heat of LNG, the big feature here is that the use of the cold and heat of LNG has beenfurther expanded to produce air-separated gases, which are in turn supplied as refrigerantfor the production of liquid hydrogen at the same site. We view the Sakai LNG Terminaland the nearby liquid hydrogen production plant as a model for future LNG receivingterminals.


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PS4-6.9

Figure 8. System Flows of Liquid Hydrogen and Air Separation Gas Plant

Table 4. Major Equipment at Hydro Edge Company

Equipment Type of gas Production capacityLiquid Hydrogen 3,000 L/h x 2Liquid hydrogen

production system Compressed Hydrogen 600 m 3 N/h

Liquid Oxygen 4,000 m 3 N/h

Liquid Nitrogen 12,100 m 3 N/hAir separation gas

production systemLiquid Argon 150 m 3 N/h

Liquid Hydrogen Plant

Air Separation Gas Plant

HeatExchanger

Air

Liquid Nitrogen-196

Liquid Oxygen-183

Liquid Argon(-186

LN 2

LAr

LO 2

LorryShipmentLiquid Air

RectifyingTower

0.64MPa-169

LNGHeat-Ex

Liquid Nitrogen

4,000kL

50kL

965kL

Compressor

Product Tank

Steam

Reforming

PSA Unit(CO 2,H 2O removal)

Liquefier

N2 Gas

H 2 Gas

CO 2 Gas

Pure Water

LH 2

Liquid Hydrogen(-253

H 2 CO 2

CH 4 2H 2O 4H 2 CO 22MPa

Room Temp 300kL

LN 2

Compressor

Lorry

Shipment

Product Tank

LNG

NG return

NG

Sakai LNG

Liquid Hydrogen Plant

Air Separation Gas Plant

HeatExchanger

Air

Liquid Nitrogen-196

Liquid Oxygen-183

Liquid Argon(-186

LN 2

LAr

LO 2

LorryShipmentLiquid Air

RectifyingTower

0.64MPa-169

LNGHeat-Ex

Liquid Nitrogen

4,000kL

50kL

965kL

Compressor

Product Tank

Steam

Reforming

PSA Unit(CO 2,H 2O removal)

Liquefier

N2 Gas

H 2 Gas

CO 2 Gas

Pure Water

LH 2

Liquid Hydrogen(-253

H 2 CO 2

CH 4 2H 2O 4H 2 CO 22MPa

Room Temp 300kL

LN 2

Compressor

Lorry

Shipment

Product Tank

LNG

NG return

NG

Sakai LNGSakai LNG


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PS4-6.10

2.2.4 Loading. Last to be explained are gas loading and its background, considered the most characteristic send-out method of the Sakai LNG Terminal. Smaller terminalscapable of loading coastal LNG carrier have existed for some time, but the loadingfacilities of the Sakai LNG Terminal were designed and built for loading large LNGtankers.

a Japans Electric Power Supply and Demand Structure and Positioning of LNG-Fired Thermoelectric Power Generation

Figure 9 shows the annual power consumption of Japan. Large peaks are seenin the summer months of July and August in comparison to other periods. Giventhis consumption pattern, it is necessary to carefully balance power sources so asto ensure supply stability in respect of economics, environmental conditions and operating conditions of individual power sources.

Figure 9. Annual Electric Power Consumption in Japan

Figure 10 shows the power source structure of Kansai Electric Power and electric power consumption in fiscal 2005. Because of its high power generationcapacity, nuclear power is the best source in terms of fuel supply stability,economics and environmental load. After that come coal-fired power generationand LNG-fired power generation. Nuclear and coal-fired power generation are

positioned to deliver about the same output throughout the year, while, because of its good environmental qualities and output balancing capability, LNG-fired

power generation is positioned about the middle of the supply structure so as toabsorb the fluctuations in electric power consumption.

million kW

FY 2001FY 2000

FY 1995

FY 1990

FY 1985

FY 1975

FY 1965

Month

million kW

FY 2001FY 2000

FY 1995

FY 1990

FY 1985

FY 1975

FY 1965

Month


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Figure 10. Plant Capacity and Power Generation by Energy Source of Kansai Electric Power

b Improving Supply and Demand Balance of LNG

Demand for natural gas has risen worldwide in recent years, spurring increasesin the supply of LNG. Japan, which is the worlds largest importer of LNG,

procures LNG via long-term take or pay contracts and has gradually built a LNG procurement environment. In addition, because of the aforementioned seasonalfluctuations in LNG consumption for power generation and the need to make upfor demand that other power sources cannot cover or in other words as a mean for hedging power source risks, particularly a company like Kansai Electric Power,

which relies greatly on nuclear power generation for supply, must operate LNG-fired power generation more flexibly and improve the supply and demand balanceof LNG. This balance was before achieved on the supply side by joint purchasingwith other LNG buyers and spot procurements, but because the Sakai LNGTerminal has infrastructure for loading the largest class of ocean-going LNGtanker, it improves the supply and demand balance of LNG.

c Loading Facilities

Loading is done by reversing the flow through unloading equipment. There are

6 purpose-specific pumps capable of delivering 320 t/h each. Therefore a 140,000m3 class LNG tanker can be completely loaded in about 30 hours. It is believed that the Sakai LNG Terminal is the only one of its kind in the world with thisscale of loading. Though presently there are no customers seeking LNG supplythis way, this loading function will enable LNG supply inside and outside Japanand improve terminal use as LNG procurement practices diversify and changeshape from the current long-term contracting to spot procurements.

1033

890

456

841

954

0

500

1000

1500

2000

25003000

3500

4000

4500

P l a n t

C a p a c

i t y 1 0 , 0 0 0 k W

691

156

308

252

105

0

200

400

600

800

1000

1200

1400

1600

P o w e r

G e n e r a t

i o n

1 0 0 m

i l l i o n

k W h

Oil/OthersLNGCoalHydroNuclear


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PS4-6.12

3 QUANTITATIVE DISASTER RISK ASSESSMENT

Because the Sakai LNG Terminal was to be located on the outskirts of an urban area,a risk assessment was done in the planning phase to quantitatively and logically analyzethe accident potential of the LNG facilities and demonstrate the safety of the terminal to

permitting authorities and local residents. Results were publicized and led to agreementswith authorities and residents. These results were applied to the basic design of the safetysystems and other aspects of the terminal. The adequacy of the aforementioned compactequipment layout was verified by this risk assessment.

Japans LNG terminals boast a solid safety record with no major accidents havingoccurred in the 30-odd years since LNG was first introduced. However, because there isnot data on accidents, probability theories based on accident potential were an unfamiliar subject in the industry.

The authors closely examined accident databases for Japanese oil storage tanks and

the like, as well as data from the Great Hanshin-Awaji Earthquake of 1995. This data wasthen looked at in consideration of the characteristics of LNG and LNG equipment, and applied to LNG terminal equipment to identify the potential risks of an LNG terminalnever before seen in the world. Furthermore, an impact assessment was done based onthese results in order to quantitatively and logically assess the greater accident risks of theLNG receiving terminal.

Here following is illustrated and reported the specific evaluation technique of the risk assessment, from the basic concepts to results, which was done at the terminal.

3.1 Basic Concepts

The risk assessment policy followed the Risk Assessment Guidelines for Petrochemical Plants set forth by the Fire and Disaster Management Agency. Thoseguidelines indicate as the basic concept the use of a dual axis risk matrix consisting of accident frequency and impact range parameters to assess the comprehensive dangers or risks and examine preventative measures suited for the potential impact of those risks(Fig. 11-1,2).

Figure 11-1. Basic Concept of Disaster Risk Assessment

Estimate of Probability

Estimate of ImpactAssessComprehensive Risk ExaminePreventative Measures

Estimate of Probability

Estimate of ImpactAssessComprehensive Risk ExaminePreventative Measures


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Figure 11-2. Risk Matrix

3.2 Risk Assessment

The basic procedure of the actual risk assessment was conducted according to Risk Assessment Guidelines for Petrochemical Plants set forth by the Fire and Disaster Management Agency.

3.2.1 Assessment Procedure. Table 5 gives the specific assessment steps and explanations thereof.

Table 5. Assessment Procedure

Step Explanation

1

Selection of target equipment to assessSelect equipment of a relatively high degree of danger based on thequantity of hazards there are and their proximity to publicinfrastructure.

2

Extraction of accident factors and setting of initial eventSet a thinkable cause of accident such as a natural disaster (i.e.earthquake, etc.) or accident that could occur any day. Set the initialevents for each cause of accident based on past cases. If no cases exist,use FMEA.

3

Event Tree Analysis (ETA)Develop an event tree of the development process of an accident fromthe initial events, including whether emergency equipment works or fails, whether fire or gas spreads or is contained, etc.Estimate the final events of the accident by adding the probability rateof each event obtained from databases.

4Estimation of impact range

Evaluate the impact range of gas dispersion, radiating heat, etc., for theevents of relatively high probability obtained by ETA.

5

Comprehensive risk assessment

Assess the comprehensive risk using the risk matrix based on accident probability (frequency of occurrence) and impact range.

AA AA

AA

AB

ABC

ABCD

BCDD

Risk Level

AA

A

C

D

B

Priority of Preventative Measures

Top

High

Medium

Low

Unnecessary

Probability

Impact

Very High

High

Medium

Low

Very Low Low Probable High

AA AA

AA

AB

ABC

ABCD

BCDD

Risk Level

AA

A

C

D

B

Priority of Preventative Measures

Top

High

Medium

Low

Unnecessary

Probability

Impact

Very High

High

Medium

Low



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3.2.2 Estimation of Accident Probability. The most important step of the risk assessment was to estimate the accident probability or frequency of occurrence. For this,the last 5 years of accident databases for the approximate 85,000 oil storage tanks inJapan were used. When there was not a case involving an LNG tank, the causes of accidents with oil storage tanks were examined. The characteristics of LNG (i.e., non-

corrosive, etc.) and LNG equipment were taken into consideration to identify the accident probability of LNG tanks.

To estimate the probability of emergency equipment working or failing at a branchevent of the event tree analysis, equipment reliability data was applied to a fault treeanalysis of the individual equipment components.

Figure 12 shows a representative example of an event tree analysis.

Figure 12. Example ETA of Leak from LNG Tank Pipe Flange

Also, to estimate the accident probability in the event of an earthquake, accident datafrom the Hanshin-Awaji Earthquake was examined and used. The Great Hanshin-AwajiEarthquake was a shallow earthquake of 7.3 magnitude that struck in a heavily populated urban area in 1995. In the hardest hit areas, oil tanks leaked and LPG leaked from a pipeflange of a 20,000-ton capacity tank, forcing approximately 28,000 households and approximately 72,000 people to evacuate. In the risk assessment of the Sakai LNGTerminal, the accident probability in an earthquake was estimated using as parametersaccidents that occurred with the roughly 1,000 oil tanks in and around Kobe City, whichwas directly hit by the violent tremors of the Great Hanshin-Awaji Earthquake.

3.2.3 Estimation of Impact Range. Using the results from the event tree analysis, theimpact range of the accident was estimated for an accident frequency of 10 -7 time/year for everyday accidents and 10 -5 time/earthquake for earthquake-driven accidents. Thesefrequency of occurrence values are given as reference in the Risk AssessmentGuidelines for Petrochemical Plants set forth by the Fire and Disaster Management

Agency.

P 0 =5 10 -5

Notes.P 0 is the initiating event probability, which is set based on accident data for hazardous substance facilities.P 1, P 2, P 3 are branch event probabilities, which are set based on equipment reliability data.

P 1=0.99998

P 2=0.9999

1-P 2=0.0001LNG Leakfrom TankPipe Flange

Initiating Event

1 10 7

Success

Failure

Leak detection& Pump stopping Consequence

5 10 5

5 10 9

1 10 11

Success

LNG collecting system(Pipe, Pan, Pond)

Water curtainsystem

1-P 3=0.002

P 3=0.998

Gas Dispersion

PartialGas Dispersion

1-P 3=0.002

P 3=0.998

Gas Dispersion


Success

Success

Failure

Failure

P 0 =5 10 -5

Notes.P 0 is the initiating event probability, which is set based on accident data for hazardous substance facilities.P 1, P 2, P 3 are branch event probabilities, which are set based on equipment reliability data.

P 1=0.99998

P 2=0.9999

1-P 2=0.0001LNG Leakfrom TankPipe Flange

Initiating Event

1 10 7

Success

Failure

Leak detection& Pump stopping Consequence

5 10 5

5 10 9

1 10 11

Success

LNG collecting system(Pipe, Pan, Pond)

Water curtainsystem

1-P 3=0.002

P 3=0.998

Gas Dispersion


1-P 3=0.002

P 3=0.998

Gas Dispersion


Success

Success

Failure

Failure


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Table 6 gives the estimated impact range for the major events of the impact rangeanalysis by the frequency of occurrence. And, Fig. 13 gives the estimated impact range of gas dispersion caused by a leak from a pipe flange of an LNG tank.

Gas dispersion was calculated using the Sakagami formula, which is the Gaussian

Plume Model. The formula is introduced in the guidelines of the Fire and Disaster Management Agency. The model is simple and cannot do calculations withconsiderations for gas density, heat balance, etc., but conclusions are on the safe sidewhen applied to gases that are lighter than air such as methane, the main constituent of LNG.

Table 6. Estimated Impact Range for Major Accidents by Frequency of Occurrence

No Equipment Category Event Probability Impact range

1 Everyday 510-5

/year

2 Seismic

Gas dispersion

(Water curtainworking) 310-4

/earthquake

Area around

affected equipment

3

LNG tank pipe flange

EverydayGas dispersion(Water curtainnot working)

110 -7 /earthquake

Area around affected

equipment

4 LNG pipe weld (Parallel to city road) Everyday Gas dispersion510 -7

/year Within plant

grounds

5 LNG pipe weld (Crossing city road) Everyday Gas dispersion510 -7

/year


equipment

6 Everyday 510-7

/year

7

Gas pipe flange(Parallel to city road)

Seismic

Gas dispersion310 -4

/earthquake


equipment

8 Heavy oil tank pipeflange Everyday Fire210 -7

/year


equipment


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Figure 13. Estimated Impact Range of Gas Spread Caused by Leakfrom LNG Tank Pipe Flange

3.3 Assessment Results

Figure 14 shows the risk matrix of final results. As can be seen, emergency equipmentand equipment layout keep the risk level sufficiently low for all events. These resultsindicated that the risk level of the Sakai LNG Terminal was low, therefore additionalemergency hardware and layout changes were not needed. However, because theassessment contains elements of uncertainty, soft measures were examined and it wasultimately decided to ensure safety efficacy by establishing a quick response structure for emergencies within the facility and a similar cooperative structure with related outsideorganizations.

Figure 14. Risk Assessment Results Using Risk Matrix

LNG collecting pondsLNG collecting ponds

LFL/2 2.5% contoursLFL/2 2.5% contoursWater curtain do not work: 40m radiusWater curtain work : 30m radius

LNG collecting pondsLNG collecting ponds



Everyday Seismic* Event No. in this matrix is

the same as in Table 6.

Probability

I m p a c t

R a n g e

Very High

High

Medium

Low


Serious impactoutside of plant

Minor impactoutside of plant

Inside of plant

Area aroundaffectedequipment

Everyday 10 -7 10 -6 10 -5 10 -4 / year

Seismic 10 -5 10 -4 10 -3 10 -2 / earthquake

12

3

4

5

7

8

6 Everyday Seismic* Event No. in this matrix is

the same as in Table 6.

Probability

I m p a c t

R a n g e

Very High

High

Medium

Low


Serious impactoutside of plant

Minor impactoutside of plant

Inside of plant

Area aroundaffectedequipment

Everyday 10 -7 10 -6 10 -5 10 -4 / year

Seismic 10 -5 10 -4 10 -3 10 -2 / earthquake

12

3

4

5

7

8

6

12

3

4

5

7

8

6


17/17

Paper PS4-6

PS4-6 17

4 SUMMARY

This paper explained the progress of liberalization of Japans energy markets since2000 and the growth of gas markets related to LNG, and introduced the Sakai LNGTerminal that was built against this backdrop and has been in operation since January

2006. In particular, it explained the major equipment, equipment layout and businessoperations from the perspective of the compact and multi-strategy concepts that arefeatured in the terminal. Furthermore, it explained the risk assessment that was done inthe design phase of the terminal, from basic concepts to results. This risk assessment was

based on quantitative calculations using an estimated frequency of occurrence of potentialaccidents. It was one of the few comprehensive risk assessments in the world to addressan entire LNG terminal.

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