Peak-shaving scheme for coal-fired power plant integrating flexible carbon capture and wastewater treatment

Abstract

Carbon dioxide capture and peak-shaving are two of the main challenges facing conventional coal-fired power plants today. This paper proposes a peak-shaving scheme for coal-fired power plant integrating flexible carbon capture and wastewater treatment to control pollutant emissions and equate supply and demand in electricity generation. Aspen Plus software is adopted to model and determine the optimal parameters of the system through sensitive analysis. Additionally, through analyzing the relationship between the electricity demand and power output, the peak-shaving scheme is applied by extracting excess steam to desorb carbon dioxide at off-peak time and decreasing steam extraction at peak time. Finally, a detailed thermodynamic and economic analysis of the whole system is carried out. The simulation results show that the carbon capture subsystem achieves a minimum heat duty of 3.70 MJ/kg CO2 at a monoethanolamine concentration of 34%, a CO2 lean loading of 0.34 and a stripper pressure of 0.8 bar. In addition, with energy storage, 90% of CO2 is captured and the wastewater treatment capacity is 1167.1 m3/day. The results of economic analysis indicate that the levelized cost of electricity is 93.8 USD/MWh and payback period is 6.66 years.