SIMULATION OF THE RECOVERY OF BOIL-OFF GAS AT LNG STORAGE SECTION AND EXPORTING TERMINALS

Abstract

The model of a Liquefied Natural Gas plant from treatment stage to the shipping section was designed using the Aspen Hysys v8.6 and the Boil of Gas (BOG) occurred at three sections which are depressurization section (also called knock-out/flash drum), the storage section and the shipping section. The purpose of the research was to design a recovery strategy for the boil-off gas at the shipping/jetty section. The following results were obtained as recovery process covered all point of BOG in the plant, 240960kg/day of BOG was recovered from the depressurization and storage tanks while 227952kg/day was recovered from the jetty section during shipping. The composition of the gas from these points are 99.99% methane and 0.0001% ethane. From the research, it was deduced that two integral gear motor compressors of power 1120.52kW at jetty and 1253.52kW at storage and depressurizing sections are suitable for the recovery of the BOG. From the economic analysis, a sum of $3,790,605 will cover the equipment purchase, installation, and an annual running cost while a total of $138,121,200 was obtained from sales of total BOG. With this careful work, the gas flaring issue at the LNG export will be curbed and revenue will rise.