An innovative process for simultaneous removal of CO_2 and SO_2 from flue gas of a power plant by energy integration

摘要

With the fast development of the society, the amount of carbon dioxide has been increased enormously in the atmosphere all over the world, which has already endangered the survival of human being. More and more people or organizations are studying new technologies to reduce the cost of capturing CO_2. The recovery and sequestration of CO_2 from flue gas of the power plant is regarded as a feasible way to mitigate the greenhouse gas emissions. Therefore, the process of recovering carbon dioxide by chemical absorption with monoethanolamine (MEA) in industry was emphatically described in this paper. Based on energy integration, a coupled process was proposed which included MEA absorption of CO_2 and SO_2, and the heat recovery from the flue gas's waste heat recovery unit and compressor inter-stage cooling unit. Compared the innovative process with an original process, 9% of thermal energy could be reduced in the new flowsheet. Meanwhile decarbonization and desulphurization could be carried on in the absorber simultaneously without the usual wet flue gas desulphurization (FGD) system. An exergy analysis model was established and validated by the literature data with a deviation less than 5.40%. The exergy results indicated that the exergy loss of the improved process was 15.48-20.75% less than that of the original one, which proved that the innovative process was reasonable and effective from the perspective of energy utilization.