Industrial ultra-low carbon methanol synthesis routes: techno-economic analysis, life cycle environment assessment and multi-dimensional sustainability evaluation

Abstract

This study established industrial green hydrogen-coupled coal-to-methanol process (GH2-CTM) and biomass-to-methanol process (BTM) from the perspectives of process coupling and raw material greening. A comprehensive comparison of the two low-carbon methanol synthesis routes was conducted, aiming to promote environmentally friendly and efficient methanol production. Based on detailed process modeling and simulation results. Techno-economic, and life cycle assessments were performed on these low-carbon methanol processes as well as the conventional coal-to-methanol process (CTM), and multi-dimensional feasibility analysis was performed on key parameters (such as green hydrogen coupling amount, green hydrogen price, carbon tax, and biomass policy subsidies). The findings revealed that the industrialized GH2-CTM process exhibited a 16.2% increase in methanol production and a 16.5% reduction in energy consumption. As the cost of green hydrogen decreases to 10.52 CNY/kg, renewable energy electrolysis hydrogen production could potentially replace the water gas shift unit, leading to a 46.4% increase in methanol production and approximately 62.5% and 55.0% reductions in GHG emission and NED consumption compared to the CTM process. Government subsidies for straw-based energy production resulted in comparable economic performance between the BTM process and the CTM process. The BTM process demonstrated significant reductions in GHG emission and NED consumption, approximately 62.1% and 41.2% respectively. These findings can ensure the realization of genuine ultra-low carbon methanol production under the premise of determining the industrial scale, and provide guidance for the more sustainable and environmentally friendly transformation of large coal-based methanol plants in China.