Simulation of chilled ammonia process based carbon capture power plant and optimization of coupling method

The simulation model of chilled ammonia process (CAP) and power plant were established and verified by using Aspen Plus. Simulation results show that the energy consumption of the reboiler in CO2 capture process is 1.26 GJ/(tCO2) and the energy consumption of the reboiler in ammonia capture process is 1.42 GJ/(tCO2). Three returning methods for draining from CO2 capture system and three returning methods for drain from ammonia capture system to the power plant were proposed and optimized. Results show that the drain from the CO2 capture process returning to the inlet of the fifth heater and the draining from the ammonia capture process returning to the inlet of the seventh heater are the condition of optimum coupling methods. Under the condition of optimum coupling method, the net output of the power plant decreases by 127.17 MW and the overall thermal efficiency decreases by 7.44%, the overall standard coal consumption of the power plant increases by 58.28 g/kWh and the overall heat consumption increases by 1705.80 kJ/kWh, similar to the conventional mono ethanol amine (MEA) based carbon capture. Under the optimum coupling method, when carbon capture rate of the power plant increases by 5%, the net output of the power plant decreases by 7.48 MW, the overall efficiency decreases by 0.44%, the overall standard coal consumption increases by 4.09 g/kWh and the overall heat consumption increases by 119.58 kJ/kWh. © 2016, Zhejiang University Press. All right reserved.