Catalytic Oxidation of Ethanol for Treatment of Commercially Produced Carbon Dioxide Using Aqueous Sol–Gel-Derived Catalyst Materials

The purpose of this study was to design a Pt/TiO2–ZrO2 catalytic-based treatment system to remove ethanol and oxygen (O2) from a gaseous feed stream. The ultimate target application was the conversion of ethanol and O2 to carbon dioxide (CO2) and water (H2O) from a feed stream of CO2 in a commercial beer brewing operation. Bench-scale reactions were performed at 250 °C and 300 °C, representing two temperatures under practical consideration for a full-scale catalytic reactor. The target gaseous feed stream would be expected to have a relatively low (near-stoichiometric) concentration of O2, so the effect of O2 concentration was also studied. On the bench scale, ethanol was completely converted to CO2 under low flow rate conditions, and the reactions proceeded through volatile and non-volatile reaction intermediates. Results from the bench-scale tests were used to make predictions for designing a pilot-scale catalytic reactor under conditions of high and low O2 concentration. A pilot-scale reactor was constructed and installed in a commercial brewing facility, and results from testing the pilot-scale reactor are also presented. The pilot-scale system reduced the feed stream ethanol concentrations by 99.9% while concomitantly reducing the O2 concentrations over the course of a six-day demonstration period without generating unacceptable levels of byproducts.