A Review: Six Common Syngas Generation Pathways and Comparison in Terms of Carbon Emissions

To shift to sustainable development, syngas generation has been regarded as a promising industry. Syngas is a valuable intermediate for greenhouse gas re-utilization and various value-added products production. For syngas production, there are various pathways and mechanisms using different phases of feedstocks under distinct temperature and pressure conditions. This paper based on the data from existing literature gives insight into the mechanism of six common syngas generation pathway: dry reforming, steam reforming, partial oxidation, autothermal reforming, bireforming, and gasification, while the feedstock is methane or underground coal. Simultaneously, the mechanism suggests a possible origin of carbon emissions from heating. A overview of environmental impact of carbon dioxide emissions from several channels is presented to facilitate a horizontal comparison among each technique. The comparison indicates a hierarchy of various mechanisms from a sustainability standpoint, demonstrating that autothermal reforming exhibits the highest performance in minimizing environmental impact. The limitations and prospects of sustainability research in syngas generation are articulated, including methods to enhance sustainability evaluation.