Evaluation of Municipal Solid Waste Conversion to Dimethyl Ether via Gasification and Electrochemical Upgrading System Based on Aspen Plus Simulation

CUI Dongxu; HU Xiaoyu; LIU Xianning; WU Zhaoyang; XU Yue; YU Mengzhu; ZHOU Jianbin; CHEN Dengyu

doi:10.20078/j.eep.20250202

Abstract：The conversion of municipal solid waste into high-value dimethyl ether can reduce carbon dioxide emissions.Aspen Plus was used to simulate the preparation of dimethyl ether from municipal solid waste gasification and electrochemical upgrading in order to evaluate its reaction characteristics,simplify the syngas upgrading process,and optimize system parameters.The dimethyl ether yield and carbon dioxide emission reductions were calculated during system operation.Using municipal solid waste as a raw material and oxygen as a gasifying agent,the gasification characteristics were compared between the as-received and dry bases.The effects of varying gasification oxygen equivalence ratios and gasification temperatures on system performance were investigated,focusing on dimethyl ether,steam,and oxygen production,as well as carbon dioxide emission reductions.The results showed that the contents of carbon dioxide and water vapor in the syngas were excessively high during the gasification of municipal solid waste in the as-received state,resulting in a hydrogen-to-carbon ratio greater than 2 after electrochemical upgrading,which did not meet syngas requirements.Therefore,the dry base of municipal solid waste was selected for simulation.Increasing the gasification oxygen equivalence ratio increased dimethyl ether,steam,and oxygen production,as well as carbon dioxide emission reduction.A lower gasification oxygen equivalence ratio led to incomplete gasification,while an excess of oxygen causes over-oxidation,resulting in higher energy consumption.With the increase in gasification temperature,the production of dimethyl ether and carbon dioxide emission reduction first increased and then stabilized,while steam and oxygen production first increased and then decreased.At lower gasification temperatures,a high hydrogen-to-carbon ratio of syngas was observed.A higher gasification temperature led to a decrease in steam and oxygen production.The optimal reaction process parameters of the system were a gasification oxygen equivalent ratio of 0.275 and a gasification temperature of 850℃.At this time,consuming 100 kg/h of municipal solid waste produced 51.44 kg/h of dimethyl ether,288.19 kg/h of steam(300℃),and 33.99 kg/h of oxygen,which could reduce carbon dioxide emissions by 196.81 kg/h.It can be concluded that gasification of municipal solid waste in the dry base results in higher quality syngas.Higher production of steam,oxygen,and dimethyl ether can be achieved.Due to the conversion of carbon from municipal solid waste into liquid fuel,carbon dioxide emission reduction is achieved at the same time,demonstrating good environmental benefits.This study provides a reference for the harmless treatment and resource utilization of municipal solid waste.