Zeolites for CO2-CO-O2 separation to obtain CO2-neutral fuels

Abstract

Carbon dioxide release has become an important global issue due to the significant and continuous rise in atmospheric CO2 concentrations and depletion of carbon-based energy resources. Plasmolysis is a very energy efficient process for reintroducing CO2 into energy and chemical cycles, by converting CO2 into CO and O2 utilizing renewable electricity. The bottleneck of the process is that CO remains mixed with O2 and residual CO2. Therefore, efficient gas separation and recuperation is essential for obtaining pure CO, which via water gas shift and Fischer-Tropsch reactions, can lead to the production of CO2 neutral fuels. The idea behind this work is to provide a separation mechanism based on zeolites to optimize the separation of carbon dioxide, carbon monoxide and oxygen at mild operational conditions. To achieve this goal, we performed a thorough screening of available zeolites based on topology and adsorptive properties using molecular simulation and Ideal Adsorption Solution Theory. FAU, BRE and MTW are identified as suitable topologies for these separation processes. FAU can be used for the separation of carbon dioxide from carbon monoxide and oxygen and BRE or MTW for the separation of carbon monoxide from oxygen. These results are reinforced by pressure swing adsorption simulations at room temperature combining adsorption columns with pure silica FAU zeolite and zeolite BRE at a Si:Al ratio of 3. These zeolites have the added advantage of being commercially available.