Chemical looping reaction of methane with oxygen from La0.8Sr0.2FeO3-δ and La0.8Sr0.2FeO3-δ -Fe2O3 systems to syngas

Abstract

AbstractThe reaction of methane with oxygen from La0.8Sr0.2FeO3-δ (LSF) and several LSF-Fe2O3 configurations was studied in chemical looping mode. Shell (LSF) and core (Fe2O3) (four catalysts called CS-3, CS-4, CS-5 and CS-6, over a range of coverage), LSF mixed uniformly with Fe2O3 (UM) and Fe2O3 (front) followed by LSF (PIS) were packed in a tubular reactor. The reaction was conducted at 900 °C and weight hourly space velocity (g methane/g catalyst/h) of 3 h−1 in 20 min reduction (10 mol% methane in nitrogen) and 20 min oxidation (10 mol% oxygen in nitrogen) cycles. LSF, CS, UM and PIS configurations yielded a significantly different performance (methane conversion, CO, CO2 and H2 selectivity and coke formation) measured in 10 reproducible cycles. The reaction and XRD data indicate that CO2 and steam formed by combustion of methane on Fe2O3 modify the phase composition of LSF, inhibits the initial LSF activity and improves the performance. Feeding a mixture containing 0.4 mol% CO2, 10 mol% methane in nitrogen to LSF confirms the positive effect of CO2 on the performance of LSF.