japan’s first lng satellite

7/27/2019 JAPANS FIRST LNG SATELLITE

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Paper PS6-6

PS6-6.1

THE CONSTRUCTION OF JAPANS FIRST LNG SATELLITETERMINAL FOR LARGE INDUSTRIAL CUSTOMERS

Atsuhiko Hattori

Masaru Sekiguchi

Kazuyuki Yamaguchi

Energy Production Deputy Tokyo Gas Co., Ltd.

Tokyo, J [email protected]

[email protected]@tokyo-gas.co.jp

Kou SutouLNG Engineering Section

Tokyo Gas Engineering Co., Ltd. Tokyo, J apan

ABSTRACT

To meet gas demand in remote areas where it is difficult to access existing pipelines,Tokyo Gas began a first trial in April 2006 regarding the Sowa satellite terminal in thewestern part of Ibaraki Prefecture. This project involved the construction and ownershipof a LNG satellite terminal and local pipelines and the supplying of gas to a number of large industrial customers.

The location for this satellite terminal was limited in a small section of an industrialarea, even though the gasification capacity had to be large enough to vaporize 40,000 tonsof LNG per yearan amount equivalent to that of the largest LNG satellite terminal inJapan. Moreover, it was necessary to reduce LNG unloading time so as to increase thetransportation efficiency of LNG lorries. Higher reliability was required due to a lack of

backup supply sources for the satellite terminal. This situation differed from that of ordinary LNG terminals, which are generally connected to each other by pipelines.

To satisfy the above difficulties, Tokyo Gass entire body of knowledge related toLNG equipment was consolidated and examined, and new solutions were found. The

following engineering achievements of the Sowa satellite terminal are spotlighted and backed up with actual data.

- Reduction in space by adoption of atmospheric vaporizers with hot air generators

- Improvement of LNG lorry transportation efficiency with the reduction of LNGunloading time by half

- Reliability analysis using Tokyo gas operational data for major forms of equipmentfrom over 30 years


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Trends of LNG Utilization in Japan and Satellite Terminals

Japan is surrounded by the sea and relies predominantly on imported energyresources. About 97% of natural gas imports are made in the form of LNG. Figure 1shows that demand for natural gas has been growing as a proportion of the energy utilized

in Japan. This is largely due to growth in demand for industrial and commercialapplications.

Figure 1 LNG utilization trends in Japan

Tokyo Gas predominantly meets natural gas demand in the National Capital Area bysupplying natural gas through the major high-pressure pipelines as shown in Figure 2 andthrough a mesh of interconnected low-pressure pipelines.

Figure 2 Japans metropolitan Tokyo and location of SOWA

Figure 2 shows Japans metropolitan Tokyo and location of Sowa LNG satelliteterminal.

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2002 2003 2004 2005 2006

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2002 2003 2004 2005 2006

Increase Increase Flattening Out

Tok o

Pacific Ocean

Sowa baraki Prefecture


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Figure 3 Pipeline networks of Tokyo Gas and gas supply

Figure 3 also shows some locations in the National Capital Area that do not have pipelines. Natural gas demand in these areas has been met by LNG satellite terminals. Wesupply gas from LNG receiving terminals to the satellite terminals by lorries, small LNGtankers, and trains. The optimum scheme is selected after considering supply volume andrequirements such as reliability and cost. LNG satellite terminals incorporate storagetanks and vaporization and odorization facilities, and supply natural gas directly through

pipelines to customers in the vicinity thereof.

In the past, large industrial customers in areas without natural gas pipelines weregenerally supplied through via onsite LNG satellite terminals constructed on a customer'sown premises. However, sales of natural gas as LNG via onsite terminals requires specialtransportation facilities and expensive cryogenic materials to handle the LNG, makingnatural gas less viable than competing fuels such as oil. Onsite schemes also have thefollowing disadvantages, regardless of the type of fuel involved.

Need for the customer to provide land for the terminal Construction costs that are high in comparison with the low level of demand

Need for separate facility operation and maintenance work for each customer

In spite of these issues, areas without pipelines included locations in which there wereconcentrations of large potential customers. Some such customers expressed interest inswitching to natural gas if it could be supplied by pipeline, avoiding the need to set asideland or to maintain and manage LNG facilities.

To take advantage of this situation, Tokyo Gas developed an off-site natural gas

supply scheme, whereby gas could be supplied to a number of large industrial customersin areas lacking access to transmission pipelines. This would be achieved by constructing

Gotenba CityFuji City Shizuoka

Gas

Nagano

Gunma

Kumagaya

Utsunomiya Hitachi

Kofu

Washimiya Gas

Tosai Gas

Tobu Gas Ibaraki

Tobu GasIbaraki-Minami

TsukubagakuenGas

Ohtaki Gas

Keiyo Gas

Bushu Gas

Akishima Gas

Atsugi Gas

Hatano Gas

Higashi-NihonGas

Odawara Gas

Joso

Daito Gas

Ohta City Gas

TobuGas

Moriya

Mt. Fuji

Fujiyoshida City

Tokyo Gass service areaTokyo Gass service areaService areas of other gas companies

(TG wholesale reception)High-pressure transmission pipelines (of TG)High-pressure transmission pipelines (of others)

NarashinoCity-OwnedGas

Submarinetrunkline

Keihintrunkline

Yokohamatrunkline

Headquarter

Loop trunk line

Chiba Gas

SodegauraNegishiOhgishima

3 LNG Receiving Terminals

Sowa


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LNG receiving satellite terminals owned by Tokyo Gas and equipped with their ownvaporizers and local pipelines.

Figure 4 Supply via off-site LNG satellite terminal

This scheme was introduced in April 2006 at the Sowa LNG satellite terminal in thewestern part of Ibaraki Prefecture, which is Japan's first off-site type LNG satelliteterminal. The features of this natural gas supply scheme are shown in Figure 4.

This approach has allowed users outside the coverage zone of the National CapitalArea pipeline network to take advantage of natural gas as a fuel without having to handleLNG or deal with the issues of LNG terminal provision, operation, or maintenance.

This method of gas supply is only viable with an appropriate combination of customer size, transportation distance, and plant investment. Also, transportation by truck is moreexpensive than transportation by pipeline because of the cost of transportation and of thefacilities required.

Moreover, the economics of the situation do not improve with increases in volume,and viability may even deteriorate as size increases, due to the need to ensure reliabilityof transportation and to secure land for terminal sites. Consequently, solutions such asoff-site LNG satellite terminals are only appropriate when a number of specificconditions are met. However, this approach does provide a further method that increasesthe range of options available for meeting the demand for natural gas.

Satellite LNG Terminal

Off-site type LNG terminal

User A

On-site type LNG terminal

LNGvap.

User B

User C

User D

Self-useLNGvap.

User A

Self-useLNGvap.

User B

Self-useLNGvap.

User C


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The Const ruct ion o f the Sowa LNG Satellite Terminal

Figure 5 shows an outline of the process flow for the Sowa LNG satellite terminal.

Figure 5 Schematic diagram of process flow and appearance of theSowa LNG satellite terminal

The characteristics of the terminal are described below.

There are 2 LNG tanks at this terminal. One is for supplying gas (high-pressuretank) and the other is for receiving it (low-pressure tank). The total LNG supplysystem works to create an exchange between such tanks.

Pressurizing gas derived from pressurizing vaporizer is introduced into a LNGtank that supplies LNG to keep the supply pressure higher, and this system does

not require LNG pumps.

L

G

L

G

L

G

L

G

LNG

LNG

LNG

BOG

LNG

HAV HAV HAV HAV HAV HAV

LNGNGNG

BOG

LNG receiving equipmentLNG vaporizer

BOG superheaterLNG pressurizing vaporizer

Cushion drum

Gaspipeline

Odorizer

LNG tankLNG tank:LNG

:Pressurizing NG

:Supply NG

:BOG


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This system is superior to a system that uses LNG pumps because of its extremelylow power consumption, lack of necessity to restart pumps when a power blackout occurs,and low maintenance requirements.

Certain topics pertaining to the construction of the terminal are examined below.

(1) Efficient Utilization of Narrow Construction Space

It was necessary to rationally configure the required facilities in a limited space because this terminal was set up in a small section of an industrial area, although theamount of LNG to be handled was about 40,000 tons per year (domestic maximum scale).

By means of adopting various designation methods, a reduction of space and cost-cutting for operation of the terminal were achieved. Such measures included reduction of receiving lanes as a minimum requirement, increasing the number of runs from the LNGreceiving terminal to the satellite terminal, and use of a LNG vaporizer with the adoption

of the HAV, which has large capacity for vaporizing gas and does not require a boiler.

(2) High Eff iciency of Transport ation and Low Management Costs at theTerminal

The Sowa terminal is located at Koga city in Ibaraki prefecture, more than 140 kmfrom the nearest LNG receiving terminal. As for this satellite terminal, because thetransportation costs for gas supply via lorries are higher than those for pipelines, it has

been necessary to reduce the required costs and to construct and manage the terminal withan eye to business profits to as great an extent as possible.

From the point of view of reduction of initial costs and transportation costs, higher transportation efficiency has necessitated the use of fewer lorries.

Moreover, from a safety viewpoint, it was determined that lorries should be operatedduring the daytime.

A one-way trip from the LNG receiving terminal to the satellite terminal involvestravel over a long distance (more than 140 km) and it takes quite a long time (about 3hours). Time is increased because traffic jams often occur in metropolitan areas.

In general, it takes more than 90 minutes to receive LNG, involving tasks such as

connecting flexible tubes and purging gas. However, at the Sowa terminal, it became possible to radically shorten the required time to about 45 minutes at the most with theimplementation of the following measures.

A constant supply of high-pressure gas from the terminal

In general, lorries are equipped with vaporizers. During the unloading process,some of the supplied LNG is directed into the vaporizer, and highly pressurized vapor gas is introduced into the lorry tank to pressurize the LNG loading line. However,

pressure decreases with this method as the unloading of the LNG progresses, so it isdifficult to shorten the time of unloading. This defect is avoided by constantlyintroducing the pressurized gas from the vaporizer in the terminal to the LNGreceiving line


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Pipes with large diameters for LNG receiving lines

In the unloading of LNG, if the diameter of a receiving pipe is too small, then pressure loss becomes large and the unloading time becomes longer. To avoid this problem, we adopted pipes with larger diameters.

An automatic control system Many satellite terminals have implemented manual operation systems to open and

close their valves. By adopting the automated control system mentioned below for theoperation of valves, it was possible to shorten the operation time.

(3) Highly Reliable Gas Supply

LNG receiving terminals are connected with each other via gas pipelines, so if oneterminal fails to supply gas, the total amount of gas supplied may be kept constant bysupplying more gas from other terminals. As the Sowa terminal does not connect withother terminals or pipelines and no gas holder exists, if there is a failure of the under stream line of LNG tanks, it would become impossible to satisfy the target gas demand.Therefore, it was necessary to design a highly reliable facility. Above all, in the case of designing the P&ID of terminal, based on the conclusions of data from reliability analysis,we were able to quantitatively evaluate the critical conditions that ensure the reliability of the entire terminal. This allows for the successful supply of gas and feedback for theterminal.

The following material describes some aspects of the above matters in greater detail.

Adopti on of Hot Ai r Draf t Superheater with Air Fin Vapori zer (HAV)

At domestic satellite terminals, the most common means of vaporizing LNG involvesthe use of natural draft air fin vaporizers. Such equipment utilizes ambient heat, and thuscosts very little to operate. However, due to the accumulation of frost on the heatexchange surface, the vaporizers can be continuously operated for only a limited duration,making changeover vaporizers essential.

Moreover, in colder regions, hot water vaporizers and accompanying hot water generation equipment are also needed to counter drops in the temperature of gas as itexits air fin vaporizers. As a result, the overall vaporizer system becomes very complex,making for high construction costs. The large amount of fuel required as a heat source for

hot water vaporizers in winter also makes operation very expensive.To overcome these problems, we adopted the HAV (a hot air draft superheater with

air fin vaporizer), which was developed by Tokyo Gas and Tokyo Gas Engineering. TheHAV is a low-cost, energy-efficient vaporizer that incorporates a hot air source into asingle unit based on a conventional air fin vaporizer.

Such vaporizer consists of a vaporizer, superheater, and hot air draft generator asshown in Figure 6. After the forced-draft vaporizer makes maximum use of the ambientatmospheric heat to vaporize the LNG (-162C in its liquid form), an auxiliary hot air draft is produced in the superheater to boost the temperature of the gas.


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Figure 6 Basic outline of HAV

Certain features of the HAV are mentioned below.

As it can be used in all seasons, it does not require hot water during winter, andthis saves space while contributing to a reduction in construction costs.

Compared with systems that combine natural-draft air-fin vaporizers with hotwater vaporizers, the HAV is a simple system that makes the maximum use of ambient atmospheric heat, so the ratio of the amount of gas consumed to theamount of gas produced (the fuel gas rate) is very low. Under severe weather conditions (snow, 0C, and 90% RH minimum), when the ability to vaporize islow, the fuel gas rate is very low (0.2%), at 1/10 of the figure for hot water vaporizers.

If the temperature is higher than 5C, neither hot air nor fuel gas are required.

Table 1 shows the comparison of HAV system with Conventional vaporizer systems.

Hot air draft generator

Air AirCombustor

LNGNG

SuperheaterFan

Vaporizer


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Table 1 HAV system vs. conventional vaporizer systems

Advanced Operation with In troducti on of Automat ion System

In order to reduce the costs required for management and for ensuring safe operationof the terminal, a complete automation system was introduced for the similar type of receiving terminals.

In particular, this was achieved by using manual operation while attemptingcoordination with lorry operators. Numerous valves with pressure gauges are operated byhand at the site in harmonization with unloading equipment of other terminals. At the

satellite terminal, the unloading facilities and the number of lorries used were minimizeddue to space restrictions, and the necessity of reaching peak unloading frequency wasemphasized. A compact yet complete automation system was introduced. To this end, aseries of operations such as purges and cooling down of the lines used for unloading wasautomated to as great an extent as possible, thus achieving a greatly shortened unloadingtime. To meet the requirements of the terminal, various functions were automated with aDCS (distributed control system), including processing for starting and stopping eachvaporizer in line with changes in gas supply and the implementation of exceedinglystreamlined unloading operations. Operational errors were also decreased, suitableoperator guidelines were drawn up for power blackouts, and reports were madeconcerning terminal material balance.

Type HAV system Conventional vaporizer systems

SchematicFlow

One vaporizer de-ices while the

other vaporizes.

Hot water type:

100% * 1 (base load)

Air fin type:100% * 2(exchange for de-icing)

Initial cost 0.8 1.0Running cost 0.3 1.0Space for installation

Small Large

Other information

Suitable for low temp. area; morethan 28 vaporizers adopted

LNG NG

1.0/h

1.0/hNG

Hot water

utility

Air fin type

1.0 t/h *2

Air fin type

1.0 t/h *2

Hot water type

1.0 t/h *1

LNG

HAVA-line (0.5 t/h)

HAVB-line (0.5 t/h)


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As a result, it was possible to minimize the number of required operators to a single person in many cases (and to only two persons in the case of unloading work).

In general, the control system of the satellite terminal is designed with the backupcontrol system, which is equipped with minimum functions for a breakdown and is very

different from the normal control system. The frequency of breakdown or maintenance islow, but operators feel a sense of incompatibility and their mental burdens become largeas operation differs greatly from the normal system. At the Sowa satellite terminal, it wasassumed that backup control system would be constructed as a duplicate of the normalsystem, including software architectures that would curtail human error and preserve safeoperation under irregular conditions with a minimal number of operators.

As a result, during maintenance or failure of the normal system, operators can usuallycontinue their work smoothly without a sense of incompatibility.

Figure 7 Schematic diagram of Sowa Satellite Terminal Plant Control System

As for the operation of valves and controls, in Japan, almost all methods involvingoperation by hand are generalized and necessitate a small number of workers, based on

trust in the skill of the operator and consequent reduction of construction costs. However,in the case of this terminal, it was possible to greatly reduce the time required for unloading with the use of an automation system. Moreover, such automation alsorepresented an attempt to greatly reduce labor costs.

Highly Dependable Design Using Reliability Analysis

When the P&ID for the terminal was settled on, the critical conditions for reliabilityof gas supply were determined. Quantitative evaluation using reliable analysis methodswas implemented to ensure usefulness and the reliability of gas distribution throughoutthe terminal. The resulting feedback was used in the design process.

Reliability Index for Reliability Analysis

Monitor 3HSS3

Monitor 2 Monitor 1HSS1

For ReportDOHS1LC Panel

DOHS1 HSS3 HSS3TSS2

LC Panel

TSSC2 TSSC1

Communicato Communicator

Operation con trol desk

Receiving lane

Cubicle

Main control system

tri l ex

Backup control system

tri l ex

device device

Field

Duplex bus

(Distributed Control System)


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Target demand

Time

Evaluation period

Designed demand

D e m a n

d o f

T e r m

i n a l

1 2

Case (A)

ti concerns a period in which target demand is not satisfied during the evaluation periodand is used to evaluate general events.

Target emand

Time

D e m a n

d o f

T e r m

i n a l

Evaluation period

Designed emand

Sum where ( Designed Target

Case (B)

If 1, then Ur (evaluation period). Ur concerns provability where target demand isnot satisfied during the evaluation period, so it often used for evaluation of events that frequentlyoccur and cause serious impacts (such as power blackouts).

The following are typical examples of indices for quantitative calculation, andevaluation took place based on the resulting figures.

Ua and Ur are defined as below.

Ua: UnavailabilityThis concerns provability where target demand is not satisfied.Ua = MTTR / (MTBF + MTTR) * MTTR

Ur: UnreliabilityThis concerns provability where target demand is not satisfied for 1 month.Ur = 1 R (R: Reliability) * t Here, t = time period (continuous running for 1 month)

v

Figure 8 The meanings of the unavailability and unreliability reliability factors


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Reliability Index Calculation Method for Reliability Analysis

Figure 9 Example of calculation of the unreliability reliability factor

From the above model, unavailability and unreliability for the entirety of plant Xare calculated from the indices of each facility, which are components of X.

In general, when the resulting values are small, the reliability of the system is higher.

Results of Reliability Indices for Designed Terminal

During the design process, index calculations were performed for a line configurationmodel based on ideas concerning other existing terminals with a reliability analysis tooldeveloped by our company. It was possible to draw on company results from over 30years, and the reliability data needed for the calculation calculate were based on operationand maintenance result data concerning major types of equipment.

As a result, it turned out that defenses against power failure and the redundancy of theline greatly influenced reliability.

The design of P&ID for the new equipment could not but involve reliance on the

experience, know-how, and intuition of the designers, among other factors. The list of factors that influence gas distribution reliability for the entire terminal system, involvingthe adoption of reliability analysis technology and quantitative evaluations, can be easilycompleted by virtually anyone over a short period of time. Thus, this case will surely

prove instructive for reliability assessment and the like during the future construction of similar facilities.

Pump 10 t/h

a ( = 0.1)

Pump 10 t/h

b ( = 0.1)

Target demand

Case 1 5[t/ h]

Case 2 15[t/ h]

Plant

Vaporizer 20 t/h

c ( = 0.1)

2 ( Uaa + Uab ) + Uac

( 0.1 + 0.1 ) + 0.1 = 0.30

Case 2

15t/h

1 ( Uaa * Uab ) + Uac

( 0.1 * 0.1 ) + 0.1 = 0.11

Case 1

5t/h

Ua for total plant XTarget Demand


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Conclusion

This case represents the first attempt at construction of a satellite terminal of maximum scale in Japan targeting only big customers.

The Sowa terminal was constructed in a compact space while conserving costs andusing highly reliable equipment.

For many reasons, it is believed that industrial customers will increase in number, andthus it is thought that similar terminals will be constructed in the future. It is possible tocontribute to the expansion of natural gas use, providing clean energy with lowenvironmental impact in Japan, if various conditions are met, such as those involving

pipes, receiving terminals, and locations.

japan’s first lng satellite

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