Transporting Cleaner Fuel to Japan
|
|
 |
|
Doublely safe: Transporting natural gas safely at low temperatures requires an expandable orthogonally corrugated membrane of nickel stainless steel S30400. |
|
|
Stainless steel may give NKK Corporation the upper hand in the small but growing niche market for
ships that transport liquefied natural gas (LNG) to Japan
Nickel magazine, Sep. 01 -- NKK lines the hulls of its LNG carriers with a corrugated
membrane made of
S30400 stainless steel. The 1.2-millimetre-thick lining enhances the hull's ability to withstand
cryogenic temperatures (-163°C), required to transport natural gas in its liquid state, thereby improving
safety and reliability. Each carrier uses about 90 tonnes of S30400 stainless steel.
The double-hull structure also prevents catastrophic failure of the storage tanks, even when the tanks are
damaged, because the orthogonally corrugated membrane system is expandable. Any stress is released through
the orthogonal membrane and the gas pockets that form there have a damping effect on the sloshing load.
Other advantages of the LNG carrier design include: optimum use of hold space; reduced overall dimensions and minimized gross tonnage; structural hull continuity; good visibility from the flat deck; good maneuverability and propulsive efficiency; and less sloshing due to optimum cargo tank dimensions.
When NKK first licensed the GTT Mark III membrane technology from Gas Transport & Technigaz of France in the early 1970s, oil and coal were the primary fuel sources in Japan. But a growing interest in cleaner energy increased the demand for imported natural gas. The cleanest-burning fossil fuel now accounts for more than 10% of the primary energy market in Japan, though the weak domestic economy has dampened energy use somewhat.
Since 1993, NKK has delivered four LNG carriers (containing the unique membrane cargo containment system) to customers transporting natural gas to Japan. The first three orders were 18,800-cubic-metre ships, which are now in service between Malaysia and Japan. The fourth ship, a 22,500-cubic-metre carrier, was recently chartered by Pertamina, Indonesia's state-owned petroleum company, to transport fuel from its terminal in Bontang to two regional gas companies in Japan.
The two gas companies plan to import 200,000 tonnes of LNG annually for 15 years to supply cleaner fuel to their districts. The ship order represents a first for Pertamina, which, until now, has time-chartered only carriers with the Moss-type spherical aluminium LNG containment system.
The demand for LNG by local gas companies in Asia is creating a niche market for LNG carriers, says Shunsuke Takahashi, head of NKK's Asia-America Newbuilding Ship Sales. NKK's compact carrier is the economical choice for smaller companies that move lighter loads and lack large storage areas and/or port facilities, he says.
A feasibility study by NKK concluded that direct importation of fuel to these districts from ports in other parts of Asia is more economical than laying pipelines or transporting LNG by ship from existing terminals owned by other utility companies in Japan.
In 2000, Japan imported about 54 million tons of LNG, accounting for more than half of the world's LNG trade. Major suppliers of LNG include the US, Brunei, the United Arab Emirates, Indonesia, Malaysia, Australia and Qatar.
NKK's best-selling LNG carriers are 130 metres long and 26 metres wide. They contain three cargo tanks that can hold a total of 18,800 cubic metres of fuel.
Photo: NKK CORPOORATION
<< Previous -- Next >>
