Worldwide cryogenics - Japan

Worldwide cryogenics- Japan The Tokyo Gas Company Y. Ishimasa

Since 1885, the Tokyo Gas Co, the largest private city gas company in the world, has been supplying gas to Tokyo for more than 90 years. At present, its customers number about 5.6 million and gas sales amount to about 2.1 x 105 million cubic feet a year. Tokyo Gas, as a public utility corporation, is destined to supply to consumers a stable flow of clean, non-pollutive gas and to promote energy saving which is now the national request. For the sake of this mission, Tokyo Gas decided to make LNG (Liquefield Natural Gas) the main source of city gas and began to import LNG in 1969. Furthermore, the conversion of conventional gas production and supply into natural gas offers the following advantages: resources saving due to the no energy loss processing; contribution to the environmental protection; additional capacity to pipelines; and rationalization of the gas production system etc. Therefore, Tokyo Gas set the Natural Gas Conversion Programme as one of the most important projects and started it in 1972. By the end of 1977 the number of converted customers amounted to about 2.4 million, 43% of the total.

1974

1975

1976

1977

4 499

4 720

4 892

5 050

5 189

274

286

294

304

321

Industry

25

25

24

24

24

Others

35

36

38

40

41

4 833

5 067

5 248

5 418

5 575

Total

Households

The Japanese LNG project In 1969 LNG was first introduced from Alaska to Japan at the Negishi Works of Tokyo Gas, and this was the beginning of Japan's natural gas age. Continuously gas is supplied to Japan from Brunei in 1972, from Das Island (Abu Dhabi) and Badak (Indonesia) in 1977.

1974

1975

1976

1977

108 763 117 663 122 827 135 362 133 372

Commerce

32 226

35 018

36 502 39 871

Industry

14 841

17 456

19 505 21 189 20 722

8234

9929

Others Total

11519

12961

40 331

13251

164 064 180 071 190 353 209 383 207 606

Unit: million ft 3, 562 BTU ft -3)

Proportions of materials 1973 1974 1975 1976 1977 LNG Natural gas

LPG

1973

Commerce

1973

Naphtha

Consumers of LNG

Households

Volume of gas sales

Crude oil

31. 8 40. 9 45. 8 52. 7 57. 8 (1.4°x 106 tonne) 9. 5

6. 5

6. 3

5. 9

5. 6 (6.28 X 109ft 3)

21. 3 22. 0 18. 9 18.1 13.1(535x103kl) 4. 8

4. 6

3. 4

.

3. 9 .

.

3. 3 .

3. 6 (91.8 x 103 tonne)

.

Offgas

16. 0 14. 3 14. 8 13. 8 1 4 . ° ( 1 5 . 6 x 1 0 9 f t 3)

Coal&coke Others

12. 7 11. 5 0. 5 0. 2

Total

9. 8 0. 5

5. 8 0. 4

5,6(1.11x106t°nne) 0. 3

100. 0 100. 0 100. o 100. o 100. 0

LNG transported from abroad is stored in LNG tanks at the receiving and regasifying terminal, it is then pumped and vaporized into natural gas. For city gas, natural gas is caloriecontrolled by mixing it with LPG and supplied to customers. For thermal power plants natural gas is used in its pure form. Fig. 1 shows the processes involved. LNG storage tanks

(In addition, there is a project to import LNG from Sarawak in Malaysia.)

Facilities at a LNG terminal are LNG storage tanks, vaporizers, pumps, compressors, etc; each of them is composed of stainless steel or aluminium (alloys) to endure low temperatures lllK.

At present, six LNG receiving and regasifying terminals are in operation including Tokyo Gas's Negishi and Sodegaura Works.

Only the LNG storage tanks of Tokyo Gas's Negishi and Sodegaura works are described, because other kinds of facility are widely known.

The author is at the Tokyo Gas Company Ltd, 2-16 Yaesu 1-chome, Chuo-ku, Tokyo, Japan. Received 19 May 1978.

LNG storage tanks are roughly classified into above-ground and under-ground types.

CRYOGENICS. FEBRUARY 1979

0011-2275/79/020067-06 $02.00 © 1979 IPC Business Press

67

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Fig. 1 Processflow diagram

To assure the safety of the receiving terminals as a whole, Tokyo Gas developed under-ground storage tanks. Since 1970, when a 10 thousand kl under-ground tank was constructed at the Negishi works, Tokyo Gas has constructed larger scale under-ground tanks and now there are 12 smoothly operating tanks three at Negishi and nine at Sodegaura. The reasons why Tokyo Gas has eagerly intended to develop underground storage tanks are as follows:

The under-ground storage tanks are substantially safe since LNG does not spill out as liquid, even if a part of the tank is damaged by an accident. This is because the liquid level in the storage tank is kept below the surrounding ground level. . Since only a portion of the tank is above ground level, the under-ground storage tanks can easily harmonize with the surrounding environment.

1. In Japan, where earthquakes are very frequent, safety from earthquakes is the most important factor govern-

Membrane Insulation

ing large-scale storage tanks in which flammables are stored.

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Fig. 2 Strong b o t t o m plate type o f the 60 000 kl LNG in-ground tank at the Sodegaura Works, Left half shows shell structure constructed by IHI and right half by Kajima

68

CRYOGENICS. FEBRUARY 1979

3. In-ground storage tanks of large capacities can be constructed economically by making the appropriate ground condition plans. Fig. 2 shows a section of one of the 60 000 kl LNG in-ground tanks at Sodegaura Works. As mentioned above, Tokyo Gas began to import LNG in 1969. Due to the increase in demand of city gas and the advance of the Natural Gas Conversion Programme, Tokyo Gas constructed Sodegaura Works at Chiba, Prefecture, in 1973 as the second LNG receiving terminal. After the construction of the Sodegaura Works, the number of Tokyo Gas's LNG receiving and regasifying terminals became two and the basis of a stable gas supply was established. Tokyo Gas's LNG import projects have all been promoted in co-operation with The Tokyo Electric Power, the largest electric power supplying company in Japan. LNG for power generation is all processed on commission at Tokyo Gas's LNG terminals.

Fig. 3 A 95 000 kl underground tank in operation at the Negishi terminal. To the right of the picture is a second tank which is under construction

LNG facilities of Negishi and Sodegaura Works are still increasing and the final mass of LNG imported will amount to about 2 million tonnes for Negishi and I0 million tonnes for Sodegaura. Negishi Terminal The Negishi Works at Yokohama, started in 1966 as a city gas production factory using initially naphtha and LPG. In November 1969 LNG was imported from Alaska and it changed to a LNG terminal. The LNG facilities increased and it began to receive Burunei LNG in January 1973. LNG facilities there are still increasing. The table shows the main facilities of the Negishi Works now in operation and under construction. In addition there are SNG (Substitutional Natural Gas) plants using naphtha for the sake of supporting LNG.

Fig. 4 The Sodegaura Terminal showing in foregound the LNG jetty, underground and above ground storage tanks. Behind the terminal is the T o k y o electric power generation plant

Facilities at the Negishi Terminal Facilities

No.

Scale

LNG storage tank (above-ground)

3 2

45,000 kl 35,000 kl

LNG storage tank (under-ground)

1

10,000 kl

1 3

60,000 kl 95,000 kl

LNG vaporizer (open-rack type)

LNG vaporizer (submergedcombustion type)

5 1 1

45 tonne h-1 85 tonne h -1 100 tonne h- 1

3 2

45 tonne h-1 100 tonne h-1

Sodegaura Terminal Tokyo Gas began to construct the Sodegaura Terminal in 1971 as a city gas producing works, using only LNG and small mass of LPG for calorie control. The plant was ready

CRYOGENICS. FEBRUARY 1979

Fig. 5 Close up view of the Sodegaura Terminal. In the bottom right is the LNG cold utilization plant for the production of CO 2, LN 2 and LHr. The LNG vaporizer yard is shown in the bottom left of the photograph

to receive Burunei LNG in July 1973. The Sodegaura Works is to supply a large quantity of city gas to the metropolitan area of Tokyo through two main pipe lines: the Chiba main line running through Tokyo's outer districts and the submarine main line across Tokyo Bay. The pressure of gas sent out from the Sodegaura Works will reach to 70 kg cm -2 (about 1 000 Psi).

69

The Sodegaura Works, like the Negishi Works, is located adjacent to the thermal power generation plants of Tokyo Electric and it not only sends out city gas (natural gas, 1236 Btu/ft 3) but also supplies enough natural gas for the power plants. LNG facilities now in operation and under construction are shown in the Table. Facilities at the Sodegaura Terminal Facilities

No.

Scale

LNG storage tank (above-ground)

2 1

45,000 kl 60,000 kl

LNG storage tank (under-ground)

11

60,000 kl

LNG vaporizer (open-rack type)

LNG vaporizer (submergedcombustion type)

7 7 3

60 tonne h-1 100tonneh -1 120tonneh -1

3 1

60 tonne h-1 120tonneh -1

Fig. 6 The LNG jetty at Sodegauraterminal showingtwo tankers. Left is the Das Island 125000 kl tranker and to the right is the 75000 kl Brunei LNG tanker

Utilization of LNG's 'cold"

One unique feature of LNG is its vast emission of 'cold' when vaporized from a liquid at 111 K into a gas at room temperature. This cold energy is best recovered by using LNG in low temperautre processing. Tokyo Gas has long researched techniques to use the 'cold' for the sake of cost reduction and energy saving.In 1971 Tokyo Gas began to use LNG cold heat for the production of liquid oxygen and nitrogen for the

Air ~

Air compressor

filter ~

~L~_~!

Fig. 7 An open rack type LNG vaporizer

LA

41 t

--

tank

NG compressor Crude

Condenso J--~ J

-~ I i t

,Ar purifier

"c%'r':,%

To gas

Tokyo

I

ectifier

LNG

Fig. 8 Flowdiagramof air separationplant using LNG cold 70

CRYOGENICS. FEBRUARY 1979

efficient process is adopted to the plant now under constrution at the Sodegaura terminal, the power saving ratio of which will reach 50%.

first time in the world and continuously in 1974 constructed a super-freezing warehouse. These businesses have been operated by the affiliated companies of Tokyo Gas and are located adjacent to the Negishi Works. Furthermore, a second plant for liquid oxygen and nitrogen production is now under construction adjacent to the Sodegaura Works and it will be in operation in October this year. At this moment the rate of using LNG cold will reach 18% of the LNG received by Tokyo Gas. Using LNG cold, there is no need for a refrigerant compressor and its accessory equipment compared with conventional plants, so that electric powers and industrial waters can be immensely cut down and there can be little troublesome noises.

Refrigerated warehouse. The LNG refrigerated warehouse was established in October 1974 by The Japan Super Freeze Co. which is one of the afFdiated companies of Tokyo Gas. This plant has also been successful and the expected good operation has been maintained since its start. A cold storage capacity of 28 000 m 3 (about one million cubic feet) can hold frozen seafood at temperatures o f - 3 5 ° C and -50°C, using 4 tonne h -1 of LNG. The refrigeration system is indirect for safety, R-12 freon is used as the refrigerant which recycles between the LNG heat exchanger and the unit coolers in the warehouse.

In addition to the mentioned above, LNG cold utilizing techniques are now undertaken such as cryogenic power cables, quick freezing of food, low-temperature crushing of wastes and so on.

As shown in Fig. 9, LNG is supplied from Tokyo Gas's Negishi Works at - 140°C and 48 kg cm -2 (680 Psi) to the LNG/R-12 heat exchanger, cooling the refrigerant to - 6 5 ° C . It is then sent back to the Negishi Works after being warmed to 0°C by recycle process water of the neighbouring oxygen plant mentioned above.

The following is an outline of two plants in operation in Negishi district.

Liquid oxygen and nitrogen plant. This plant was established in July 1971 as the world's first commercial plant utilizing LNG cold by one of the affiliated companies of Tokyo Gas. This plant has been successful and the expected good operation has been obtained since its start.

The refrigerant is circulated to each unit cooler in the warehouse to transfer the cold to the ambient air keeping the room temperature to the design level.

Plant production capacity is 7 000 mSh -1 (0.25 million ft3h -l) liquid oxygen, 3 050 m3h -1 (0.11 million ft3h -1) liquid nitrogen and 150 m3h -1 (5.3 thousand ft3h -1) liquid argon, using 8 tonne h -1 of LNG. The purity of each is specified as more than 99.8% for liquid oxygen and 99.999% for liquid nitrogen and argon, which is competable to a conventional plant.

There are three floors in this warehouse 1, 2 and 3 are used mostly for tuna and are kept at - 50°C. Two floors4 and 5 are used for ordinary seafood at - 35°C. This refrigeration system eliminates the refrigerant compressors and other

Preporatio~

room

As shown in Fig. 8, LNG cold heat is transferred to the recycling high pressure nitrogen at the LNG heat exchanger making up the liquid nitrogen for feed to the distillation column. Regasification of LNG occurs in the heat exchanger under approximately atmospheric pressure and then the vapour (natural gas) is boosted up to about 26 kg cm -2 (370 Psi) by the methane compressor and sent back to the Negishi Works as a source of city gas.

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The power saving ratio of this plant compared with conventional ones is about 38%. Through this experience, a more

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C R Y O G E N I C S . F E B R U A R Y 1979

71

ancillary facilities resulting in a power saving of about 60% compared with a conventional system. Also, noise and oily wastes are eliminated. Afterword At present there are such LNG projects developed in Japan as in Sarawak (Malaysia), Kangan (lran), Australia, Qatar (the

Middle East), Yakutia (the USSR) etc, and yearly I,NG imports into Japan will reach a total of about 40 million tonnes in 1985 or thereabout. To make LNG the main city gas, Tokyo Gas is studying some of these LNG projects and the proportion of city gas devoted to LNG will reach finally to about 70%. Therefore, Tokyo Gas is studying and researching to promote further security of its LNG terminals and to utilize LNG cold more effectively.

LNG Projects in Japan and LNG receiving terminals in Japan

Receiving terminal

Export terminal

Import company

Import quantity Year of contracted operation

Storage tanks (as of 1979) No. of

kt y-1

tanks

Total capacity, Type thousand kl

Kenai(Alaska)

Tokyo Electric Power Co. Tokyo Gas Co.

720 240

1969

4

160

above-ground

Lumut(Brunei)

Tokyo Electric Power Co. Tokyo Gas Co.

450 340

1973

1 4

45 260

above-ground under-ground

Lumut (Brunei)

Tokyo Electric Power Co. 3 000 Tokyo Gas Co 720

1973

7 5

360 300

above-ground under-ground

Das Island (Abu Dhabi)

Tokyo Electric Power Co. 2 060

1977

1 8

60 480

above-ground under-ground

No. 1 Lumut (Brunei)

Osaka Gas Co.

630

1972

3 1

135 45

above-ground under-ground

No. 2 Arun (Indonesia) Badak (Indonesia)

Osaka Gas Co. 1 300 Kansai Electric Power Co. -I00

1977

8

600

above-ground

Tobata

Arun (Indonesia) Badak (Indonesia)

Kyushu Electric Power Co. 1 500 Nippon Steel Corp. 600

1977

6

360

above-ground

Chita

Arun (Indonesia) Badak (Indonesia)

Chubu Electric Power Co. 1 700

1977

4

300

above-ground

Arun (Indonesia) Badak (Indonesia)

Kansai Electric Power Co. 1 700

1979

4

280

above-ground

Undecided

Osaka Gas Co.

Negishi

Sodegaura

Semboku

Himeji

72

2 000

undecided

CRYOGENICS. FEBRUARY 1979