Natural gas is the most environmental friendly fossil fuel with a high energy content and has a promising future within the energy consumption outlook. For this reason, its production from coal is gaining a significant interest, converting the most abundant, stable, and low price fossil fuel to synthetic natural gas (SNG). In this paper a technology outlook and a sustainability assessment of the technical, economical, and environmental factors is developed. It was found that the sustainability of the process depends mainly on the local price of coal and natural gas, as well as, emerging SNG technologies, also known as direct methanation. The conventional methanation process, the indirect methanation, has high capital costs but it is currently the only proven large scale technology. Although the emerging technology has not yet been tested at a commercial scale, it has a better technical performance with an net efficiency increase of more than 10 percent as results of the process stage reduction which should lead to lower capital costs requirements. Regarding the environmental performance, the conventional process produces large amounts of CO2, approximately 1.3 kg CO2 for each kg of coal, that has to be compressed and sequestered to meet the environmental targets.
Integrated process for synthetic natural gas production from coal and coke-oven gas with high energy efficiency and low emission