Comprehensive analysis of environmental impacts and energy consumption of biomass-to-methanol and coal-to-methanol via life cycle assessment

Methanol is an important basic industrial chemical. At present, coal-to-methanol (CTM) production is the main mode of production used in China, but the mining of coal has almost irreversible environmental impacts. Thus, producing methanol by replacing coal with abundant biomass resources has been identified as a promising alternative approach. Before large-scale application, it is necessary to study the environmental impacts and energy consumption of biomass-to-methanol (BTM) methods to evaluate their capacity to replace CTM production. In this work, CTM and BTM processes are modeled and simulated. Life cycle energy consumption, global warming potential, acidification potential and human toxicity potential are studied for the two processes from a life cycle assessment perspective. The results show that methanol synthesis and purification units constitute the most energy intensive facets of methanol production. Under the same production capacity, the life cycle energy consumption of BTM processes is lower than that of CTM processes and offers great advantages in terms of environmental impacts, especially in reducing greenhouse gas emissions. A sensitivity analysis identifies pipeline transport as an energy efficient and clean mode of long-distance methanol transport. From comparative results, using biomass resources instead of coal to produce methanol is identified as a feasible alternative.