Thermodynamic modeling of a power and hydrogen generation system driven by municipal solid waste gasification

Cogeneration systems for simultaneous supply of power and hydrogen have been studied extensively because of their great potentials. Accordingly, in the present study, an innovative cogeneration system consisting of a gas turbine, a gasifier, a transcritical Rankine cycle, and a proton exchange membrane electrolyzer is proposed. The system operates on municipal solid waste (MSW) with constant power output. The proposed cogeneration system is simulated under steady-state condition using Engineering Equation Solver (EES) software, and its performance is evaluated from the first and second laws of thermodynamics. The proposed system produced 3.92 MW power and 608.8 m3/h hydrogen under biomass feed of 1.155 kg/s. Under this design condition, the energy utilization factor (EUF), the total exergy efficiency, and the overall exergy destruction rate are calculated 34.71%, 29.44%, and 11,854 kW, respectively. There components of gasifier, gas turbine, and combustion chamber were introduced for owning the highest exergy destruction rate. A comprehensive parametric study was carried out, and it was concluded that the exergy efficiency of condenser has the lowest value among all components. Also, results indicate that the EUF and the total exergy efficiency can be increased by increasing the inlet temperature of the gas turbine or by decreasing the maximum pressure of the transcritical CO2 cycle. In conclusion, the proposed biomass-driven cogeneration system can produce clean electricity and hydrogen by consuming CO2. The strengths of this system are consumption of municipal waste as the main fuel, simplicity in design, as well as high productivity of hydrogen gas.