LNG READY SOLUTION USING A MARK FIT LNG FUEL TANK OPERATING UP TO 2 BARG: THE CASE OF VLOC

摘要

Most of shipowners are investigating the various possibilities which are offered to them to make their ships compliant with the ever more stringent environmental rules. When it comes to decide which solution should be implemented for a newbuilding, some shipowners are turning to the "LNG ready" concept which consists in ordering a ship designed and prepared for a rapid shift to LNG as fuel after such decision is taken. In the meantime the ship will be running on HFO in a conventional way. In this context GTT has developed LNG fuel containment solutions which minimize the duration of the retrofit operation as well as the footprint on the ship arrangement. Those solutions are mainly based on the future integration of prefabricated section incorporating LNG tank, Fuel Gas Handling System (FGHS) and bunker stations. To further facilitate the use of LNG as marine fuel, the pressure setting of the safety valve of the LNG tank could be set higher than the current arbitrary limit of 0,7 barg provided that the supporting structure is designed accordingly with justification provided by finite element 3D model structural analysis and in accordance with the "alternative design" approach or in accordance with the Limit State Design methodology described in the new IGC code and in IGF code under "Containment System of Novel Configuration". The paper aims at addressing various technical, safety and economical aspects of implementing an LNG fuel system and the impact and interest of operating the tank at 2 barg, in particular the case of Very Large Ore carriers loading in Australia.