Oxygen Removal from Oxy-Combustion Flue Gas for CO₂ Purification via Catalytic Methane Oxidation

Typical allowable O₂ concentration in recovered CO₂ for certain applications including Enhanced Oil Recovery (EOR) is as low as 100 ppmv. The removal of high content O₂ (3–5%) in oxy-combustion flue gas requires additional compression work in the conventional downstream CO₂ purification process. RTI hereby proposes to develop a novel technology for flue gas O₂ removal based on catalytic oxidation of natural gas. Preliminary catalytic tests were performed over various supported Pd and Pt catalysts under simulated oxy-combustion flue gas conditions, with the addition of a stoichiometric amount of CH₄ as a model compound for natural gas. Among the studied catalysts, Pd supported on zeolite H-ZSM-5 showed the highest oxygen conversion at relevant conditions. Compared to Pt catalysts, Pd catalysts generally showed higher oxidation reaction kinetics. The catalytic oxidation activity can be further increased by optimizing reaction gas hourly space velocity (GHSV) and total reaction pressure