Liquid Phase CO2 Hydrogenation to Synthesize Methanol: Solvent Screening, Process Design and Techno-Economic Evaluation

With the global shift towards low carbon and environmentally friendly energy sources, converting CO2 into methanol through hydrogenation is seen as an optional solution to reduce reliance on fossil fuels and promote the efficient utilization of renewable energy. However, the CO2 methanol synthesis reaction is limited by thermodynamic equilibrium, which results in low single pass conversion of CO2 and high recycling of reaction gases. In this paper, a process for synthesizing methanol through liquid phase hydrogenation is developed. This process relies on liquid phase solvents to remove the reaction products water and methanol, affecting the reaction equilibrium and breaking the thermodynamic limit. Based on Aspen Plus software, the binary interaction parameters were regressed using gas liquid equilibrium data, and the solvent's capacity to enhance the reaction system was assessed. The polar solvent tetraethylene glycol dimethyl ether (TEGDME) was selected as the liquid phase medium for the process. A liquid phase CO2 synthesis process was developed to achieve a high single pass CO2 conversion rate of 98.42 % and a methanol yield of 99.82 %.