Process simulations of large-scale CO2 capture in coal-fired power plants using aqueous ammonia solution

Analysis of large-scale CO2 capture process based on aqueous ammonia solution for a 500 MW coal-fired power plant was carried out using process simulation. Firstly, the equilibrium-based model, RadFrac, in Aspen Plus process simulator, is adopted to estimate the NH3 concentration and the flow rate of the lean aqueous ammonia. Secondly, the rate-based model, RateFrac, is used to analyze the effects of the size of the absorber. Finally, operating parameters of the CO2 absorption and regeneration processes are determined according to their effects on the whole CO2 capture process. Under the optimal condition, the CO2 output is 57.08 kg/s. For a 500 MW coal-fired power plant, the amount of CO2 captured per year can reach 1.8 million tons. Because of the restriction of the size of the columns, the predicted minimum regeneration energy is 5750 kJ/kg CO2. Capture part of the overall flue gas or paralleling more columns could be the alternative solutions for reducing the energy consumption. (C) 2013 Elsevier Ltd. All rights reserved.