The world’s first newbuild liquefied petroleum gas (LPG) FPSO, slated for operation offshore Angola, has been announced with ABS selected as the classification society of record. The vessel, to be named the SANHA LPG FPSO, will have a daily production capacity of 6,000m3 and storage capacity of 135,000m3. The SANHA will include LPG storage tanks and LPG production plants such as gas separators, gas refrigerators and boil-off gas reliquefaction units on the upper deck or topsides.
The vessel will utilize Ishikawajima Harima Heavy Industries ( IHI) Self-supporting, Prismatic-Shape, IMO Type-B tank system or SPB. ABS has previously classed the only LNG carriers to use this containment system and also classed the first LPG FSO newbuild, the Escravos, which is fitted with SPB tanks. Unlike LNG, which is primarily methane that must be stored at extremely low temperatures (-260o F), LPG is primarily propane, which can be stored at a much higher or warmer temperature (-56o F). Although the main gas compound is different, the key issues for safe storage and transportation for both gases in the liquefied form are storage temperature and the gas containment system. The SPB gas containment system is recognized by industry as particularly effective for liquid gas storage on an FPSO or FSO because of its internal tank stiffening structure and suitability for partial loading.
Mitsui & Co. Ltd. and IHI have signed the contract for the construction of the SANHA. The project is scheduled for completion mid 2004 with the first product shipped the beginning of 2005.