Sustainable methanol production processes from coal and biomass: Low CO2 emissions and high efficiency

Methanol, a versatile chemical, is predominantly manufactured in China through the coal-to-methanol (CTM) process. However, the process still faces several challenges, including high CO2 emissions and low energy efficiency, which significantly reduces its competitiveness. Here, we propose a novel methanol production process from coal and biomass, which not only effectively reduces system energy consumption and CO2 emissions, but also enhances elemental utilization and energy efficiency. The process eliminates the air separation unit to reduce energy consumption, and employs the water-gas shift adsorption-enhanced hydrogen generation unit, enabling high-purity hydrogen preparation and efficient CO2 capture. Significantly, the chemical utilization of CO2 markedly reduces carbon emissions and substantially increases methanol production. The simulation results, after optimizing the key parameters, show that the co-gasification of coal and biomass improves the feedstock utilization and produces more efficient gas. The process demonstrates superior comprehensive performance, in which the highest methanol production reached 14.0 t/h, the carbon utilization rate was 87.5 %, energy efficiency was 53.7 %, and the CO2 emission/t methanol was only 0.32 t. Compared with the traditional CTM process, the superiorities of this system are well demonstrated by the 123 % increase in methanol production, 14.3 % increase in energy efficiency, and the 88.8 % reduction in carbon emissions.