Performance Assessment of Coal Fired Power Plant Integrated with Calcium Looping CO2 Capture Process

CaL technology is a promising means for post-combustion CO₂ capture in already existing power plants, and heat integration is an effective way to lower the efficiency penalty caused by CO₂ capture. Three cases with different heat integration degree were investigated in the manuscript to predict the efficiency penalty and the specific energy consumption for CO₂ capture, aiming to find the optimum scheme of integrating capture unit into coal-fired power plant. The sensitivity analysis was also conducted to compare the impacts of key parameters. The simulation results show that the Case 3, which employs a variety of measures to improve the internal heat integration within CaL and reclaims the surplus released heat via an additional steam cycle, has the lowest efficiency penalty, 5.75%. It also indicates that heat integration in Case 3 results in a 14.4% of decrease in coal consumption, a 5.8% of reduction in power consumed by CO₂ compression process, a 13.6% of drop in power consumption in ASU, and a 31.5% of decrease in specific energy consumption for CO₂ capture. The sensitivity analysis shows that the efficiency penalty may be reduced by 0.011 percentage points for each degree decrease in temperature difference of MH-1. As the compression efficiency increases from 70% to 85%, the efficiency penalty decreases from 6.51% to 5.47%, and the specific energy consumption reduces from 2.21 MJ/kg CO₂ to 1.80 MJ/kg CO₂. Abbreviations: APH: Air Preheater; ASUL: Air Separation Unit; BFPT: Boiler Feedwater Pump Turbine; CaL: Calcium Looping; CCS: Carbon Capture and Sequestration; CFPP: Coal-Fired Power Plant; GSS: Gas-Solid Separator; HPC: High Pressure Column; HPEC: High Pressure Economizer; HPSH: High Pressure Super-Heater; HPST: High Pressure Steam Turbine; HRSG: Heat Recovery Steam Generator; IPEC: Intermediate Pressure Economizer; IPEV: Intermediate Pressure Evaporator; IPSH: Intermediate Pressure Super-Heater; LPST: Low Pressure Steam Turbine; LHV: Low Heat Value; LPC: Low Pressure Column; LPEC: Low Pressure Economizer; LPEV: Low Pressure Evaporator; ORC: Organic Rankine Cycle; RH: Reheater.