The world's first LNG carrier that incorporates the Technigaz Mark III membrane tank system was delivered in October to its owner, Asia LNG Transport Sdn. Bhd., a joint venture between Nippon Yusen K.K. and Perbadanan Nasional Shipping Line Berhad of Malaysia.
NKK built the 18,800 cu m, fully double-hull carrier Aman Bintulu at its Tsu works. Construction was completed in September with more than 2 months of sea trials and gas tests using - 190 C. liquid nitrogen and final gas trials with LNG.
The tanker is chartered by Malaysia LNG Sdn. Bhd. to transport LNG from Malaysia's Sarawak gas fields to the Fukuoka terminal of Saibu Gas Co. Ltd., Japan, which serves the northern part of Kyushu.
The gas company is japans first medium-sized city utility to import LNG for gas supply directly.
FOAM INSULATION
The 9,100 dwt vessel, which is 130 m in overall length, 25.7 m in molded breadth, and 6.5 m in design draft, is powered by a steam turbine engine and can reach a service speed of 15 knots.
The carrier incorporates the Technigaz Mark III membrane cargo-containment system with three stainless steel tanks built in the vessel's hold.
The membrane cargo tank system uses fiber glass-reinforced polyurethane foam in its heat-resistant panels, in place of conventional balsa wood, to ensure high uniform insulation.
The orthogonally corrugated stainless membrane primary barrier and the triplex (aluminum foil/fiber glass cloth) composite-material secondary barrier prevent LNG from leaking in the event of an accident.
NKK says the tanks, which required some 3,000 pieces of 1.2 mm-thick 1 x 3 m stainless steel sheet for its membranes and components, can withstand thermal contraction caused by LNG's cryogenic temperature (-162 C.) and resist load sloshing According to NKK, the new-generation Mark III membrane tanks provide the LNG carrier with a compact hull that occupies minimal space, good bridge visibility, a freely selectable hull design that allows optimal tank dimension and shape, a low, flat upper deck that allows easy maintenance, and excellent maneuverability due to small windage area.
Because of efficient use of the hold space and the requirement for fewer materials, LNG carriers with membrane tanks offer higher cost-competitiveness than other types of carriers, says NKK, with construction cost savings of some 15-20%.
FRENCH DESIGN
The tanks are based on technology licensed to NKK in 1971 by Societe Nouvelle Technigaz of France. NKK also cooperated with French shipbuilder Chantier de L'Atlantique, another Technigaz licensee, in the system's research and development.
Over the past 20 years, NKK says it has built 11 in-ground LNG storage tanks, for both domestic and foreign clients, using the original Technigaz Mark I membrane technology.
While doing so, it has continued its own research on the technology and succeeded in improving it in the Mark III version that has been applied to this LNG tanker.
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