Methane Conversion to Syngas for Gas-to-Liquids (GTL): Is Sustainable CO2 Reuse via Dry Methane Reforming (DMR) Cost Competitive with SMR and AIR Processes?

Carbon dioxide is a greenhouse gas and is obtained as a waste via burning various forms of fuels. Syngas is an intermediate in large-scale long-chain hydrocarbon (C-10- C-20 alkanes and alcohols) production processes via Fischer Tropsch (FT) synthesis, typically to obtain high quality fuels. Thus, it is of particular interest to engineer syngas production processes for FT that can consume various combustion process waste CO2 in the process and thus partially contribute to the sustainable carbon neutral fuel synthesis. In this work, a quantitative economic comparison of five alternative processes is presented for the production of synthesis gas with a hydrogen-to-carbon monoxide ratio of 2, which is suitable for feeding to the Fischer Tropsch gas-to-liquid process. Combinations of steam methane reforming (SMR), dry methane reforming (DMR), autothermal reforming (ATR) and reverse water gas shift (RWGS) are explored. An amine absorber/stripper system is used for carbon dioxide removal. The effects of the cost of natural gas and of liquid oxygen and the magnitude of a potential carbon tax are demonstrated. With current prices of raw materials, the configuration with the lowest total annual cost (TAC) features a system composed of both SMR and DMR reactors.