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

CO ₂ hydrogenation to methanol via the reverse water-gas shift (the CAMERE process) is an alternative method for methanol synthesis. High operating temperatures (600-800 °C) are required for the reverse water-gas shift (RWGS) process because of the thermodynamic limit. In this study, moderate temperatures (200-300 °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 CO ₂ conversion of the RWGS part can be significantly improved at moderate operating temperatures. One-step CO ₂ 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 CO ₂ hydrogenation to methanol through the use of ISWR.