Thermodynamic and economic analysis of direct synthesis of dimethyl ether by plasma co-gasification

Abstract

Dimethyl ether (DME) is widely regarded as the cleanest and most efficient diesel alternative fuel. The traditional production method is through the methanol dehydration process. This study proposes an innovative technology to directly synthesize DME by generating syngas through the co-gasification of coal and biomass plasma. This technology simplifies the production process and integrates the supercritical CO₂ Brayton cycle to achieve efficient waste heat and power generation recovery. In order to utilize carbon dioxide in the exhaust gas, the system introduces the alkaline electrolyzer hydrogen production process and the carbon dioxide hydrogenation methanol process. Model validation and sensitivity analysis confirmed the reliability of the system and revealed the significant impact of key operating parameters on the system performance. The results of thermodynamic and economic studies show that the system energy efficiency and exergy efficiency are 73.50% and 64.24%, respectively, with a dynamic payback period of 6.22 years and a net present value of US$89.583 million. This study provides an innovative path for the clean production of DME, effectively balancing resource utilization and environmental protection.