Life Cycle Assessment of Typical Methanol Production Routes: the Environmental Impacts Analysis and Power Optimization

China is the largest producer and consumer of methanol in the world. The methanol industry will continuously develop in the long future in China and the environmental impact of the industry is greatly concerned about. In this study, a “cradle to gate” life cycle assessment of CTM, CGTM and NTM is conducted based on the Gabi education 6.0 software. The results suggest that CTM has a much more severe integrated impact, 2.0–3.4 times of the other two routes. In CTM route, environmental burden from synthetic gas production stage contributes most, while the methanol production stage is the major contributor to the burden in both CGTM and NTM routes. Notably, for the three methanol routes, 73.33%–78.50% of integrated impact put damage on the ecosystem. In addition, electricity has been found as the most sensitive parameter. And after power optimization, the integrated impact with 100% electricity generated from clean energy, could be reduced by 82.2%, 66.5% and 83.5% in CTM, CGTM and NTM routes, respectively. The CTM exhibits the largest reduction potential. From estimation, if 100% specific electricity from hydropower/wind/nuclear is adopted in CTM, its environmental impact is nearly equivalent with that of CGTM route. Meanwhile, CTM route with 100% application of clean energy based electricity will be competitive to CGTM and NTM routes with coal-based electricity matched. Therefore, it could be effective by adjusting its technique structure and/or the intelligent use of clean energy based power to realize the objective of cleaner production and sustainable development for methanol industry, not only in China, but also in other countries in the world.