Energy and Environmental Analysis of an Innovative System Based on Municipal Solid Waste (MSW) Pyrolysis and Combined Cycle

This paper presents the energy and the environmental impact analysis of an innovative system based on the pyrolysis of MSW which produces solid (char), liquid (tar) and gas (syngas) fuels used in a combined cycle for electric power generation. The syngas, after filtration and compression, feeds two gas turbines. In turn, the exhaust from the gas turbines, after post-combustion with char and tar, drives a steam turbine power plant. Before being discharged, the flue gas is processed in a selective catalytic reduction (SCR) unit to reduce CO, VOC and NOx content and is filtered to remove particulate matter. This innovative approach to energy recovery from MSW combines high energy efficiency with a low level of polluting emissions. The estimated global efficiency of the plant, referred to the LHV of the MSW, is around 28–30%, a much higher value than ordinarily obtained in traditional waste incineration plants. The environmental analysis includes a study of the polluting emissions and the simulation of their concentration in the area surrounding the plant: the emissions of the the plant have a negligible influence on the original polluting levels of the settlement area.