Modeling and Simulation of Production Process on Dimethyl Ether Synthesized from Coal-based Syngas by One-step Method

Process Simulation and Environmental Aspects of Dimethyl Ether Production from Digestate-Derived Syngas

The production of dimethyl ether from renewables or waste is a promising strategy to push towards a sustainable energy transition of alternative eco-friendly diesel fuel. In this work, we simulate the synthesis of dimethyl ether from a syngas (a mixture of CO, CO₂ and H₂) produced from gasification of digestate. In particular, a thermodynamic analysis was performed to individuate the best process conditions and syngas conditioning processes to maximize yield to dimethyl etehr (DME). Process simulation was carried out by ChemCAD software, and it was particularly focused on the effect of process conditions of both water gas shift and CO₂ absorption by Selexol^® on the syngas composition, with a direct influence on DME productivity. The final best flowsheet and the best process conditions were evaluated in terms of CO₂ equivalent emissions. Results show direct DME synthesis global yield was higher without the WGS section and with a carbon capture equal to 85%. The final environmental impact was found equal to −113 kgCO₂/GJ, demonstrating that DME synthesis from digestate may be considered as a suitable strategy for carbon dioxide recycling.

Process simulation of dimethyl ether synthesis via methanol vapor phase dehydration

The production processes included catalytic dehydration of methanol in an adiabatic fixed-bed reactor and two columns product separations. In this study, the technological process for dimethyl ether (DME) synthesis is built on PRO/II platform based on the combined parameters of the reaction dynamic model for methanol dehydration reaction, the improved NRTL model of the liquid phase, the PR model of vapor phase. In order to validate the proposed model, the simulation results have been compared with the available data from a set of industrial production equipment with a production capacity of 200 000 tonnes per annum. A comparison between the calculated and measured results has proved that these results are satisfactory. The bed height and the volume of the catalytic bed are calculated aim at one million t/a DME yields and while taking account of high-purity DME production. After discussing the influence of feed stage location and reflux ratio for DME product purity, the suitable unit operation conditions are chosen. Accordingly, accurate process simulation results provide the basis and guidance for an improvement and development of the similar industrial device.