Energy, exergy, exergoeconomic, and environmental analyses and multi-objective optimization of a biomass-to-energy integrated thermal power plant

A novel biomass-driven heat and power cogeneration system comprising biomass gasification, a gas turbine, a Stirling engine, and a supercritical carbon dioxide cycle integrated with a domestic water heater was proposed in this work. Different biomass feedstocks (paper, wood, paddy husk, and municipal solid waste) were used in the gasifier as the input fuel. The devised system was analyzed from energy, exergy, exergoeconomic, and environmental viewpoints. Moreover, the effect of integrating the Stirling engine with the stand-alone CHP system is studied. Moreover, a detailed parametric analysis was performed to assess the effect of varying operating parameters on system efficiency. Finally, multi-objective optimization using genetic algorithm in MATLAB software was performed to obtain the optimum operating points. According to the results, using municipal solid waste as the input biomass resulted in the highest exergy efficiency by 41.36% and the lowest CO2 emission by 0.9021t/MWh. Also, the system with the Stirling engine had a higher exergy efficiency and lower CO2 emission than the system without the Stirling engine. According to the optimization results, the maximum obtainable exergy efficiency was 42.03%, which was related to MSW. Also, the minimum achievable cp,tot was 10.94$/GJ, attributable to the respective paddy husk.