Thermodynamic Analyses of a Moderate-Temperature Process of Carbon Dioxide Hydrogenation to Methanol via Reverse Water-Gas Shift with In Situ Water Removal

CO2 hydrogenation to methanol via the reverse water-gas shift (the CAMERE process) is an alternative method for methanol synthesis. High operating temperatures (600-800 degrees C) are required for the reverse water-gas shift (RWGS) process because of the thermodynamic limit. In this study, moderate temperatures (200-300 degrees C) were used for the RWGS part of the CAMERE process by the application of in situ water removal (ISWR). Thermodynamic analyses were conducted on this process using the Gibbs-free-energy-minimization method. The analyses show that by using ISWR with high water-removal fractions (e.g., 0.80-0.99), the CO2 conversion of the RWGS part can be significantly improved at moderate operating temperatures. One-step CO2 hydrogenation to methanol (CTM) with ISWR was also investigated, and it resulted in similar methanol yields. Both processes showed high potential and the ability to promote CO2 hydrogenation to methanol through the use of ISWR.