How to make sustainable CO2 conversion to Methanol: Thermocatalytic versus electrocatalytic technology.

[Display omitted] • Methanol is firstly produced by CO 2 electroreduction with a CuO/ZnO/Al 2 O 3 catalyst. • CO 2 -to-methanol conversion is scaled-up from lab data process simulation results. • Electrocatalytic CO 2 conversion is sustainable with 90% of FE and 200 mA/cm2. • CO 2 -to-Methanol could be economically competitive at productivity >20 kg/h methanol. • The carbon footprint is 62% lower for both processes using 100% of renewable energy. Electrocatalytic (EC) and thermocatalytic (TC) conversion of CO 2 to methanol are promising carbon capture and utilization technologies. Herein, these CO 2 -to-methanol conversion processes are analysed in terms of technical, environmental and economic feasibility. To this purpose, the catalytic performance of the same catalyst (CuO/ZnO/Al 2 O 3) was evaluated in both EC and TC processes. Here is showed for the first time that this catalyst is (apart from TC route) also able to generate methanol through CO 2 EC reduction. This work presents lab scale tests, scaled-up simulations and evaluates the environmental and economic performance of these processes. The carbon footprint of the TC and EC processes, scaled-up to the same productivity of ~ 3 kg/h methanol, scored ~ 8 kg CO2 eq /kg CH3OH. Strategies to reduce this impact are presented, such as improving the current density of the EC cell (i.e. 200 mA/cm2 results in a reduction of 68% to 2.72 kg CO2 eq /kg CH3OH) and the availability of 100% renewable electricity (saving up to 62% carbon footprint of both processes). Considering an effective allocation of the methanol productivity on a real market scenario, both the TC and EC processes would start to be economically competitive at methanol productivities > 19.1 kg/h and 3.3 kg/h, respectively. Moreover, if O 2 valorisation, a low price of the renewable electricity and a carbon tax are considered, the economic profitability will rise; e.g. the minimum levelised cost of product (LCOP of 1.45 €/kg and 1.67 €/kg, respectively) could be reduced by 53%. Finally, our results pointed out that the CO 2 electroreduction process must be optimized (e.g. improving catalysts performance and EC cell design reducing mass transfer limitations) to achieve industrially relevant rates and the maturity of the thermocatalytic technology. [ABSTRACT FROM AUTHOR]