Comparative study of MSW heat treatment processes and electricity generation

This paper discusses the latest analysis in solid waste thermal treatment methods including life cycle assessment (LCA), process systems, economic and energy analysis. The MSW collected by municipalities such as paper, plastics, organic materials, glass, metals, food, leather and rubber can be utilized, via primary treatment methods which are mainly pyrolysis, gasification and combined pyrolysis gasification (P-G) cycles to generate thermal energy or electricity. The importance of solid waste treatment comes from its potential to convert waste into several sources of energy or fuels such as gasoline, syngas or diesel, eliminate waste, and reduce CO2 emissions. The process systems are explained in terms of process stages, carrier gases, operating pressures and temperatures, end products and reaction residence time. According to MSW management statistics, landfilling and incineration are considered a major activity and is incompatible with the exponential increase of global production of MSW per year. Environmental analysis shows that combined pyrolysis-gasification has lowest environmental impact with acceptable results for pyrolysis and gasification. Economic analysis shows highest capital cost for combined pyrolysis gasification (P-G) followed by pyrolysis and gasification process systems respectively. Operating and maintenance cost shows highest for pyrolysis, while gasification systems show highest revenue per ton.