A novel green methanol – heat cogeneration system based on municipal solid waste plasma gasification and coke oven gas: Energy, exergy, economic, and environmental assessment

Abstract

Burning municipal solid waste for disposal contributes significantly to atmospheric pollution. Utilizing municipal solid waste for green methanol production can alleviate environmental burdens. This study proposes a novel approach based on municipal solid waste plasma gasification, integrating coke oven gas catalytic reforming for green methanol synthesis. A comparative analysis is conducted against a conventional scheme involving water gas shift for syngas production. Simulation models of both approaches are constructed, revealing that the newly proposed system achieves higher methanol synthesis yield and energy utilization efficiency at 90.57 % and 61.28 %, respectively, with an exergy efficiency of 63.74 %. The project incurs an investment cost of 11,448.70 k$, with a dynamic payback period of 4.18 years after a 1-year construction cycle. The net present value over a 25-year operational span is 21,899.16 k$. Additionally, the proposed system emits less than 0.06 tons of carbon dioxide per ton of green methanol, significantly lower than the 0.72 tons emitted by the water gas shift-adjusted syngas synthesis scheme. It makes the proposed approach a potential negative carbon emitter compared to municipal solid waste incineration. Therefore, the system demonstrates favorable thermodynamic performance, coupling with substantial economic and environmental benefits.