Thermodynamic analysis of CO2 capture by calcium looping process driven by coal and concentrated solar power

Abstract

Carbon capture for coal-fired power plant draws an increasing attention, due to CO2 emissions may have an impact on global climate change. Retrofitting existing power plants with post-combustion CO2 capture using solvent process is one of the most mature carbon capture technologies. However, a significant thermal efficiency drop was observed when integrating coal-fired power plant with post-combustion carbon capture process. Therefore, in this paper, solar energy was introduced to the CO2 capture process, in order to recover the energy of the capture system. Coal-fired power plant with solar aided CO2 capture system ((solar+CC)+PP) and solar aided coal-fired power plant with CO2 capture system ((solar+PP)+CC) were simulated by EBSILON professional and Aspen Plus. Then, energy input, heat recovery, energy penalty and some important evaluate index of these two systems were calculated and compared. Finally, sensitivity analysis were carried out to find the influence of heat recovery efficiency, solar radiation received, purge percentage and CO2 capture efficiency. The finding indicate that the thermal performance of (solar+CC)+PP is 31.20%, which means that the overall efficiency penalty is 13.44% percentage points; the thermal performance of (solar+PP)+CC is 31.09%, which means that the overall efficiency penalty is 13.57 percentage points. However, considering technical and environmental aspects, (solar+PP)+CC is better than (solar+CC)+PP. Electricity consumption for CO2 compression accounts for the biggest proportion, over 70%, and electricity consumption for the air separation unit takes the second position.