Methanol is an important basic chemical, but its production generates a significant amount of CO₂ not only because it is an energy-intensive process but also the raw material for methanol synthesis is fossil energy. Here, a sorption-enhanced process (SEP) technology was constructed and simulated using Aspen Plus based on the four processes of coal-to-methanol (CTM), natural gas-to-methanol (NTM), biomass-to-methanol (BTM), and biomass-to-methanol with biochar (BTMC). Using the life cycle assessment (LCA) method established fossil energy demand (FED) and global warming potential (GWP) indicators to analyze the fossil energy consumption and CO₂ emissions of four processes. Compared to conventional routes, the SEP effectively reduced FED and GWP due to the reaction coupling, in-situ CO₂ capture, and syngas upgrade in a reactor. In particular, the co-product of biochar and methanol process (BTMC) attained the best FED and GWP, which were -17.085 MJ/kg-methanol and -2.457 kgCO₂-eq/kg-methanol, respectively. Additionally, this work investigated the impacts of CO₂ capture, co-production, green energy (GE), and raw material substitution on FED and GWP. The best carbon effect (-5.793 kgCO₂-eq/kg-methanol) was achieved using the BTMC&CC&GE process. And the BCH₄-TM&GE process had the lowest FED (-75.498 MJ/kg-methanol). Thus, the work suggests that while CO₂ capture effectively avoided CO₂ emissions, GE and raw material substitution were the long-term development strategies. Thus, the work suggests that while CO₂ capture effectively avoided CO₂ emissions, GE and raw material substitution were the long-term development strategies.
 

Biomass-to-methanol, Sorption-enhanced process, CO2 capture, Life cycle assessment, calcium looping