CH₄ and CO₂ Reductions from Methanol Production Using Municipal Solid Waste Gasification with Hydrogen Enhancement

This study evaluates the greenhouse gas (GHG) impacts of converting municipal solid waste (MSW) into methanol, focusing on both landfill methane (CH₄) emission avoidance and the provision of cleaner liquid fuels with lower carbon intensity. We conduct a life cycle assessment (LCA) to assess potential GHG reductions from MSW gasification to methanol, enhanced with hydrogen produced via natural gas pyrolysis or water electrolysis. Hydrogen enhancement effectively doubles the methanol yield from a given amount of MSW. Special attention is given to hydrogen production through natural gas pyrolysis due to its potential for lower-cost hydrogen and reduced reliance on renewable electricity compared to electrolytic hydrogen. Our analysis uses a case study of methanol production from an oxygen-fired entrained flow gasifier fed with refuse-derived fuel (RDF) simulated in Aspen HYSYS. The LCA incorporates the significant impact of landfill methane avoidance, particularly when considering the 20-year global warming potential (GWP). Based on the LCA, the process has illustrative net GHG emissions of 183 and 709 kgCO_2e/t MeOH using renewable electricity for electrolytic hydrogen and pyrolytic hydrogen, respectively, for the 100-year GWP. The net GHG emissions using 20-year GWP are −1222 and −434 kgCO_2e/t MeOH, respectively. Additionally, we analyze the sensitivity of net GHG emissions to varying levels of fugitive methane emissions.