Design and Economic Analysis of Boil-Off Gas Recovery in LNG Facilities

This study focuses on designing and evaluating a process plant for liquefied natural gas (LNG) boil-off gas (BOG) recovery. The lightest hydrocarbons included in LNG, such as methane and ethane, are often included in Boil-off Gas (BOG). Flaring and contamination of the environment are unavoidable in the absence of an effective BOG recovery system. Using Aspen HYSYS, a natural gas liquefaction process was simulated, emphasizing the recovery and utilization of BOG generated during various stages of LNG processing, including liquefaction, depressurization, storage, and shipping. The material and energy balances for the process were meticulously calculated to ensure accuracy in flow rates and heat exchange efficiencies. The simulation results indicate that the liquefied natural gas produced contains a methane 2473oncentrationn of 96.64% with minor amounts of ethane. BOG, mainly consisting of methane (100% purity), was effectively recovered and conditioned for reuse or flaring. An economic analysis was conducted to assess the profitability of BOG recovery, highlighting an estimated annual income of $138,121,200, with a gross profit margin of 97.3%. The total capital investment required for BOG recovery equipment amounted to $3,790,605. This study demonstrates that BOG recovery can significantly enhance the economic viability and environmental sustainability of LNG operations by reducing methane emissions and providing a valuable energy resource.