Energy, Exergy, and Environmental Impact Analysis and Optimization of Coal–Biomass Combustion Combined Cycle CHP Systems

Combined Cycle Combined Heat and Power (CCCHP) systems enhance energy efficiency and reduce emissions by simultaneously generating electricity and heat. This study presents the energy and exergy performance, environmental impact, and efficiency optimization of CCCHP combustion systems using Ebsilon Professional 16 software simulation. Three fuel combustion CCCHP systems of coal, biomass, and coal–biomass cofiring were simulated for 150 MW of total power output with 125 MW of electrical power and 25 MW of a heating energy system. The sensitivity analysis was performed for 16 different systems with the fuel moisture content varying from 10% to 40% (w/w) to identify the energy and environmental effect on simulated CCCHP systems. The simulation results indicate that increasing biomass moisture content enhanced flue gas energy and improved the Rankine cycle performance. The energy efficiency of biomass and coal–biomass combustion CCCHP systems increased from 56.90% to 67.22% and 56.94% to 62.37, with the moisture content rising from 10% to 30% (w/w) and 10% (w/w) to 25.56% (w/w), respectively, but declined beyond these. Moreover, the exergy efficiency showed a similar pattern peaking at 50.06% in biomass samples and 50.10% in the cofiring sample. Furthermore, the environmental impact, CO2 and SO2 emission concentrations reduced from 22.42% (w/w) to 20.77 (w/w) and 0.66% to 0.61%, respectively, with an increase in fuel moisture content from 10% to 25.56% in a biomass cofired combustion CCCHP system.