Water consumption of the integration of coal-fired power plant with CO2 post combustion system with different cooling methods

Abstract

CO2 capture is one of the most effective methods to reduce CO2 emissions. Integration with CO2 capture system will cause an energy penalty for the coal-fired power plant which has been extensively studied, while it also increases the water consumption that has less focus. This paper analyzes the water consumption of a coal-fired power plant integrated with CO2 capture system under three operation modes which is (1) power reduction mode, (2) constant total output power, and constant CO2 capture quantity, (3) constant total output power, and constant CO2 capture rate. Regardless of the cooling method, the thermal efficiency of the integration system is the highest when the output power is constant, and the carbon capture amount is constant. Combined with coal consumption, water consumption, output power, and CO2 emissions, the system operating in a mode with constant output power and a constant carbon capture rate is further analyzed. When the temperature rises from 130 °C to 160 °C, the total water consumption increased from 1024.71m3/h to 1069.66 m3/h. When the heat duty rises from 2.0 MJ/kg CO2 to 4.0 MJ/kg CO2, the total water consumption decreases from 1081.55 m3/h to 1000.89 m3/h due to the significant reduction in water consumption in coal-fired systems. Unit water consumption has the same trend.