Enhanced Process for Methanol Production by CO₂ Hydrogenation

In the quest for a green chemical industry, much effort is devoted to the development of technologies for methanol synthesis by hydrogenation of CO2 – available from many sources. Low-cost sources of H2 are less frequently found, but an additional source at industrial scale is the wet hydrogen by-product of chlorine production. This study presents an enhanced process for methanol synthesis by CO2 hydrogenation using wet hydrogen by-product from salt electrolysis. This process uses a stripping unit where the wet hydrogen flows counter-currently to the condensed methanol-water mixture from the flash separator after reactor. This operation removes CO2 from the methanol-water mixture thus allowing a complete recycle of CO2 while also removing the water from wet hydrogen thus avoiding its negative impact on chemical equilibrium conversion. Consumption figures are 550 kWh electricity and 0.48-1.16 ton steam per ton methanol.