Exergoenvironmental analysis of a waste-based Integrated Combined Cycle (WICC) for heat and power production

This paper investigates the exergoenvironmental aspects of a Municipal Solid Wastes (MSW)-fueled Gasification Integrated Combined Cycle (WICC). Accordingly, the environmental impacts associated to exergy destruction, total environmental impact, exergoenvironmental factor and the electricity environmental impacts (EEI) are studied. A sensitivity analysis is carried out in order to have a good insight into WICC plant performance, focusing on MSW environmental impacts (0.1-0.9 millipoints (mPts)/kg MSW) and considering only CO2 emissions as pollutant formation. The results show that the largest environmental impacts are associated to gasification and are mainly caused by chemical exergy destruction (44%) and pollutants formation (61%). The highest total environmental impact (Btot) corresponds to the highest MSW impact, due to the impacts produced by the changes in the specific exergy of the streams. Discarding CH4 and CO from pollutants formation, reduced the Btot and EEI by nearly 55%. Furthermore, the calculated EEI values (13.5 mPts/kWh) are lower than that reported for conventional energy systems (i.e. Natural gas: 22-26 mPts/kWh). Therefore, this technology could be a promising alternative for energetic valorization of MSW in the Chilean conditions.