Liquefied natural gas (LNG) carrier designers and builders are confronted with apparently conflicting capacity trends in Japan.
That was the upshot of two papers presented at the Gastech '96 conference in Vienna this month (OGJ, Dec. 9, p. 28).
Kiyotaka Takeda, director of LNG carrier design at NKK Corp., and colleagues argued there is a requirement for increased LNG capacity in new carriers, to be operated at existing terminals without the need to build new berths.
Meanwhile, Masatoh Nakamura, manager of initial planning at Kawasaki Heavy Industries Ltd., and colleagues contend that the emergence of city gas companies as LNG customers is creating a need for smaller LNG carriers to deliver to smaller berths.
NKK view
Takeda et al. wrote that rising Japanese demand for LNG has led to the increase in capacity of carriers serving current terminals from 125,000 cu m at first to 135,000 cu m in recent ships.
"The size of LNG carrier seems to be becoming larger and larger," wrote Takeda et al. "Introduction of still larger LNG carriers with cargo capacity of more than 135,000 cu m would make it yet more economical to transport large amounts of LNG.
"If new LNG berths are constructed, it will be possible to introduce larger LNG carriers without any problem. However, it will be more economical if enlarged LNG carriers were acceptable to existing LNG receiving terminals without changing any facilities."
The authors concluded that membrane-type LNG carriers of as much as 175,000 cu m capacity could be accepted at existing terminals without altering shore facilities. LNG carriers of as much as 200,000 cu m capacity could be accommodated at existing terminals with minor alterations to shore facilities, they said.
Kawasaki view
Nakamura and colleagues told Gastech delegates that LNG use in Japan is gradually spreading from the traditional big users to small- and medium-sized customers, such as city gas companies scattered along the coastlines of Japan.
The city gas companies are looking to replace city gas made from coal with LNG, on the grounds that LNG is a cleaner energy form, is superior in calorific value to city gas, and that a stable supply can be secured for a long period.
The authors reported that Hiroshima Gas Co. Ltd. and Nippon Gas Co. Ltd. have begun importing LNG using the Surya Aki LNG carrier, to replace city gas. Surya Aki is the world's smallest mass-type LNG carrier, with capacity to hold 19,000 cu m of LNG in three spherical tanks.
Surya Aki was delivered to its owners in February and now is delivering gas from the Bontang LNG export terminal in Indonesia.
Kawasaki developed technology for this small-scale LNG carrier from existing carrier technology. One problem the designers had to overcome was making this small ship compatible with shore facilities at the liquefaction site built for 125,000 cu m capacity ships.
The authors said Kawasaki has committed to continue development of technology used to build Surya Aki as the basis for a new generation of LNG carriers. For Japan's small and medium sized gas users, "Direct import of LNG is a key to the success of their conversion to LNG. Kawasaki believes that this small LNG carrier will provide the possibility for such conversion projects in the future."
Copyright 1996 Oil & Gas Journal. All Rights Reserved.
