Techno-economic and greenhouse gas emission analysis of dimethyl ether production via the bi-reforming pathway for transportation fuel

This study describes the techno-economic analysis (TEA) of Dimethyl ether (DME) production via methanol dehydration where methanol is synthesized through bi-reforming CH4, water, and CO2. A conceptual DME production plant of 500 MTPD capacity is simulated in Aspen Plus (TM). In the model, the CO2 is sourced from an ammonia production facility (CFA) or from landfill gas (CFL). The estimated minimum fuel-selling price (MFSP) is $0.87 and $0.91/gal for the CFA and CFL cases, respectively. The equivalent diesel price ranges from $1.63 to $1.70/gal, which would be competitive with the market price of conventional diesel fuel. Sensitivity analysis investigated factors such as feedstock prices, capital costs, and production scale on the MFSP. Uncertainty of the MFSP resulting from varying LFG compositions is also analysed using Monte Carlo simulation. A cradle-to-gate greenhouse gas (GHG) emission analysis, performed using GREET software, showed that emissions range from -38.2 to 34.8 kg CO2eq/MMBtu. Using landfill gas sourced CO2, the process achieved negative emissions whereas using CO2 from an ammonia plant results in higher emissions than conventional diesel (17.7 kg CO2eq/MMBtu). These results indicate that bi-reforming could be an economically and environmentally feasible pathway for DME production as a diesel substitute. (C) 2020 Elsevier Ltd. All rights reserved.