Design framework for dimethyl ether (DME) production from coal and biomass-derived syngas via simulation approach

A comprehensive thermodynamic study was conducted to evaluate the comparative efficacy of methanol and dimethyl ether (DME) synthesis using CO2 rich syngas feed. The first part of our study included assessing the relative performances of the methanol synthesis system, two step DME synthesis system, and one step DME synthesis system in terms of the COx conversion and product yield (methanol/DME) based on the Gibbs free energy minimization approach. The wide range of composition of CO2-enriched syngas feed produced by the coal and biomass gasification was simulated using Aspen Plus and the following evaluation parameters were analyzed for a broad parameter range: reaction temperature (180-280 degrees C), reaction pressure (10-80 bar), stoichiometry number (SN) (0-11), and CO2/(CO2 + CO) molar feed ratio (0-1) for isothermal as well as adiabatic conditions. Based on the equilibrium yield, one-step DME synthesis was discovered as the most viable process to utilize the co-gasification derived syngas effectively. In the second part of our study, the overall process efficiency was inspected through the process design of 1 tonnes per day (TPD) DME plant inclusive of heat integration, resulting in significant CO2 abatement and DME production with high product purity and minimum energy consumption. Consequently, one-step DME production via CO2-enriched syngas obtained through the coal or biomass gasification process is identified as the leading technology based on energy utilization and CO2 abatement.