Novel efficient process for methanol synthesis by CO₂ hydrogenation

Methanol is an alternative fuel that offers a convenient solution for efficient energy storage. Complementary to carbon capture activities, significant effort is devoted to the development of technologies for methanol synthesis by hydrogenation of carbon dioxide. While CO₂ is available from plenty of sources, cheap sources of H₂ are less frequently found. An additional source of hydrogen at industrial scale is the wet hydrogen by-product of chlorine production.This study is the first to propose an efficient process for methanol synthesis by CO₂ hydrogenation using wet hydrogen by-product from chlor-alkali production. A key feature of this novel process is the use of a stripping unit where the wet hydrogen flows in counter-current mode with the condensed methanol-water mixture resulting from the high-pressure low-temperature separator after the reaction. This operation has a double positive effect, as it removes the CO/CO₂ from the methanol-water mixture thus allowing a complete recycle of CO₂ and avoiding its presence in the product, while also removing the water from the wet hydrogen thus avoiding the negative impact of adding water on the equilibrium conversion - with consumption figures of 550kWh electricity and 0.48-1.16ton steam per ton methanol.