Catalytic (Pt-Y) membranes for the purification of H2-rich streams

CO selective oxidation (Selox) for the purification of hydrogen-rich streams was studied in membrane reactors (MRs) using Pt-loaded catalytic membranes. The catalytic membranes were prepared by the ion-exchange of FAU (Na-Y) zeolitic membranes that were synthesized on tubular a-Al2O3 supports by a secondary growth method. The catalytic MR tests were performed analysing the CO conversion, O2 selectivity and yield of the desired reaction. Different feed compositions (CO, O2, H2 and N2 content and O2/CO ratio), temperatures and pressures were considered with space-time values in the range 0.27-1.2 mgPt min/cm3(STP). The CO content in preliminary tests was 10%, 1% in the other experiments. A simulated reformate shifted gas mixture (H2 = 60%) was also used. A comparison with other literature data for MRs utilizing different membrane types and packed bed traditional reactors with Pt-based catalysts is also provided. The identified ranges of operating conditions (temperature, pressure, feed molar O2/CO ratio and feed concentration) suggest a profitable use of the catalytic MR (Pt-Y zeolite membranes) for CO Selox after the low-temperature water gas shift unit of a fuel processor converting hydrocarbons into hydrogen-rich gas, operating at similar temperature conditions.