State of art and perspectives about the production of methanol, dimethyl ether and syngas by carbon dioxide hydrogenation

The conversion of carbon dioxide into feedstock for the chemical and process industry is the most efficient way to rapidly introduce renewable energy in this value chain. Carbon capture and utilization systems are getting the attention from researchers in the last years, also due to the introduction of carbon tax in many States. Through the hydrogenation of carbon dioxide methane, hydrocarbons, ethanol, formic acid, methanol, dimethyl ether and syngas can be produced. However, methanol dimethyl ether and syngas have the lower value of lost hydrogen during the reaction, equal to 0.33, 0.25 and 0, respectively. Then, these compounds are analyzed in this review. Carbon dioxide is an industrial waste, while hydrogen is generally obtained by the electrolysis of water using surplus renewable energies. Processes and reactors reported in literature regarding the production of methanol, dimethyl ether and syngas by hydrogenation of carbon dioxide are analyzed. For the capture of carbon dioxide adsorption, absorption, membranes, cryogenic systems can be developed. An important role will have ionic liquids, under study by many researchers. Future research efforts should focus on dry reforming processes, innovative carbon dioxide capture techniques and hydrogen availability at reduced cost, and wider dissemination of these scientific and technical concepts to enlarge social acceptance.