A CO2 cryogenic capture system for flue gas of an LNG-fired power plant

In the present paper, a CO2 cryogenic capture for flue gas of an LNG-fired power generation system is proposed, in which LNG cold energy can be fully utilized during the gasification process. First of all, the flue gas is compressed to facilitate the CO2 solid formation and separation. Sequentially, the CO2-removed flue gas expands to supply most of the cold energy needed for the cryogenic process. In comparison with traditional CO2-capture systems in LNG-fired power generation cycle, the new system does not require gasifying excessive amount of LNG. Based on the HYSYS simulation, the CO2 capture pressure and temperature are investigated as the key parameters to find the appropriate working conditions of the CO2-capture system. The results show that the system can achieve a 90% CO2 recovery rate or higher if the flue gas temperature can be lowered to less than −140 °C.