Converting waste into fuel via integrated thermal and electrochemical routes: An analysis of thermodynamic approach on thermal conversion

Municipal solid waste (MSW) is a common problem as it typically ends up in landfills. MSW could be a potential sustainable energy source with proper technology considering its abundant availability and high energy content. As a part of the solution to the MSW problem, the present research investigated a new integrated gasification process to ensure the complete removal of organic compounds (tar) by splitting char and gas products. The char is directed to the combustor to produce electricity for powering CO₂-to-methanol electrolysis, while the gas products are sent to the reforming section to decompose tar into syngas. It is found that char composition is sensitive towards the syngas yield and the gasification temperature. The increase of char combustion from 20% to 50% promotes methanol production via electrolysis but suppresses the overall energy productivity due to energy loss in the power generation and electrolysis. The optimum gasification performance is observed at the air/O₂ equivalence ratio of ∼0.3 with the syngas heating value (6.4 and 12.3 MJ/Nm³), H₂/CO ratio (1.4 and 1.1) and overall efficiency of 65% and 64% for air and oxygen gasifying agents, respectively. These findings show the potential of MSW to electricity and chemical products via gasification which can increaseeconomic value and optimistically increase the residents’ acceptance.