Analysis of routes for electrochemical conversion of CO2 to methanol

Abstract

In the context of peak carbon and carbon neutrality, the utilization of CO2 has attracted attention with the aim of reducing carbon emissions by converting CO2 into high-value chemicals or energy. Methanol (MeOH), which is both a hydrogen and a carbon carrier, is considered the most promising among the CO2-conversion products. This paper focus on routes for electrochemical conversion of CO2 to MeOH using green power and green hydrogen to achieve negative CO2 emissions. Three feasible technical routes for electrochemical conversion of CO2 to MeOH are proposed in this paper: Route 1, electrolysis of water to H2 and hydrogenation of CO2 to MeOH; Route 2, electrochemical reduction of CO2 to MeOH; and Route 3, co-electrolysis of CO2-H2O to syngas and synthesis of MeOH from syngas. Techno-economic assessments of the three routes are conducted using technical maturity surveys, system simulations and cost analyses to provide reference data for route selection for CO2 conversion to MeOH in China. Compared with the other routes, Route 1 is advantageous in terms of technical maturity and commercial application prospects. Although Route 1 is presently economically unviable, it is expected to achieve profitability and commercial application in the future with decreases in the cost of renewable power and continuous development of water-electrolysis technology.