Optimization and energy consumption analysis on the BOG treatment technology in LNG receiving station

Boil-off Gas (BOG) treatment is closely related to the energy consumption and safe and smooth operation of LNG receiving stations. In this paper, BOG direct compression technology and recondensation liquefaction technology that are commonly used at present were compared from the aspects of technological process and energy consumption. Then, the effects of output volume and output pressure on the energy consumption of BOG treatment technology were analyzed. And finally, the optimization measures of BOG treatment technology were proposed. To deal with the energy loss caused by the heat-cold exchange in the process of heating and recooling of existing BOG treatment process, LNG cold energy is used to cool the compressed BOG through the heat exchanger. The cold energy of LNG itself is used to replace the recondenser, the energy consumption element of existing BOG treatment process. The BOG temperature at the exit of compressor is reduced. And thus, the energy consumption is reduced in the process of heating and recooling. The energy consumption before and after the optimization of BOG treatment technology was analyzed by HYSYS software. It is shown that the energy consumption before and after the optimization of BOG treatment technology is 2 677.82 kW and 1 990.77 kW, respectively. Obviously, the energy consumption of BOG treatment technology drops by 25.66% after the optimization.