Life Cycle Assessment of the Coal-to-Synthetic Natural Gas/Methanol Coproduction Process in Series

The coal-to-synthetic natural gas (SNG) project has realized the utilization of coal resources and the production of natural gas, but it has caused a lot of pollutant discharge. In order to solve this problem, coal gasification and methanol synthesis units are adjusted, a water gas shift device is canceled, and the coal-to-synthetic natural gas/methanol coproduction process in series with high economic benefit and risk resistance is developed. Further to obtain the pollutant emission data and impact assessment data of the process, a life cycle assessment method combined with GaBi software modeling is adopted. The breakthrough point of emission is found through the disassembly analysis of the unit. In order to evaluate the quality of the coproduction process in series in life cycle assessment, this paper compares and analyzes the coproduction process in series with the single production process under the premise of the same product yield. The results showed that the series coproduction process has 35.9% less carbon emissions than the single production process. The coal-to-natural gas coproduction process in series is a promising process with outstanding performance in economy, operability, and clean production, which has enormous potential for large-scale development.