Leading classification society Bureau Veritas has granted Approval in Principle to a 4,000 cu m Bunkering Ship concept developed by France’s world-leading LNG containment manufacturer, GTT. The concept is for a bunker tanker which could deliver LNG as ship’s fuel using tanks with a GTT Mark III Flex Cargo Containment system operating up to a pressure of 2 barg. Combining the membrane containment system with the ability to store LNG at pressure’s up to 2 barg allow the bunker vessel to have a higher capacity and increased operational flexibility.
Philippe Donche-Gay, Executive Vice President and head of BV’s Marine and Offshore Division says, “Practical LNG bunker tankers are the key to building a viable LNG supply chain on which to develop LNG as a ship’s fuel. This pressurised membrane tank concept from GTT means LNG bunker tankers can manage Boil Off Gas (BOG) better and increase loading and delivery flow rates. Our studies show it is both safe and practical. We look forward to seeing the concept taken forward to a new construction.”
Under GTT’s system the BOG management during loading and bunkering operations is made more flexible because of the wide vapour pressure operating range. Vapour can be buffered and condensed in the tanks to help the fuelled ship or feeding facility handle the vapour. Condensation may be performed by spraying LNG into the vapour phase. The higher pressure also means that during voyage and stand-by mode, the duration before gas pressure in the bunker tanker’s tanks reaches the upper limit is longer. This improves the holding time when BOG is not being consumed and reduces the use of reliquefaction plant, diminishing costs.