Experimental Evaluation of a Coated Foam Catalytic Reactor for the Direct CO2-to-Methanol Synthesis Process

The era of considering carbon dioxide (CO2) as a waste stream has passed. New methods of utilising CO2 as a carbon feedstock are currently the focus of extensive research efforts. A fixed-bed reactor containing a commercial Cu/ZnO/Al2O3 catalyst washcoated on a Cu foam was used for the synthesis of methanol through direct CO2 hydrogenation. Catalytic activity tests in this reactor were conducted at reaction pressures of 30 and 50 bar, temperatures in the range 190-250 °C, and weight hourly space velocities (WHSV) in the range 1.125-2.925 NL gcat-1 h-1. The best reactor performance was recorded at 50 bar pressure: CO2 conversion and methanol selectivity of 27.46% and 82.97%, respectively, were obtained at 240 °C and 1.125 NL gcat-1 h-1. Increasing the WHSV to 2.925 NL gcat-1 h-1 resulted in a twofold increase in methanol weight time yield (WTY) to 0.18 gMeOH gcat-1 h-1 and a decrease in methanol selectivity to 70.55%. The results presented in this investigation provide insight into the performance of a bench-scale reactor in which mass transfer limitations are non-negligible and demonstrate that metal foams are promising catalyst support structures for CO2 hydrogenation towards methanol production.