Integration and optimization study on the coal-fired power plant with CO2 capture using MEA

Based on the Aspen Plus software, MEA-based CO2 capture system, steam cycle system, CO2 compression system, AHT (Absorption Heat Transformer) and AHP (Absorption Heat Pump) models are established. Effects of the key parameters on the MEA regeneration energy consumption are analyzed. Two different integration ways are proposed. The steam supplied for regeneration of the solvent will be extracted before it is directed to the low-pressure (LP) turbines and the original LP feeding water heater system will be replaced by the new integration subsystem. The main integration processes of CO2 capture unit with the original power plant mainly includes the following four parts: (1) adding a letdown steam turbine and a heater for the parameter match before the steam is supplied for regeneration process; (2) the recovery of heat from the gas that mainly consists of CO2 and H2O at the top part of the stripper; (3) the heat recovery from the CO2 compression process; (4) the recovery of heat with application of AHT and AHP. The performance of a case of 600 MW coal-fired power plant with 85% CO2 capture based on MEA system is studied and the system net efficiency only reduces about 6–8 percent points.

► We modeled the MEA-based CO2 capture system from the coal-fired power plant.
► Effects of the key parameters on the REC are analyzed and optimized.
► We proposed two different integration ways in order to reduce the energy consumption of CO2 capture.
► Application of heat pump technology when integrating the CO2 capture system with steam system will significantly lower the energy consumption.