Design of multifunctional catalytic reactor for methane partial oxidation by combining Mn-hexaaluminate and MgO with uniform and non-uniform mixing methods

The combination of multifunctional catalysts was beneficial to methane conversion and hydrogen production. In order to improve the synergistic effect of different functional catalysts, LaMnAl11O19 and MgO catalysts were loaded on Al2O3 pellets to prepare LaMnAl11O19/Al2O3 (LMA) and MgO/Al2O3 (MA) catalytic pellets. Through the uniform distribution and non-uniform mixing of LMA and MA, the different catalytic reactors were built to study the methane combustion performance. The results indicated that the high-activity center of Mn4+ in LMA increased methane activation rate and the abundant oxygen vacancies in MA promoted active oxygen migration. When the bed length ratio of LMA to MA was 2:2, the oxygen migration rate and methane activation rate achieved the optimal coupling and reached the highest hydrogen energy conversion efficiency of 55.5%. Meanwhile, the good low-temperature catalytic activity and the shortest stabilization time of 4322 s were obtained when the LMA was located in the inner layer. The increase of LMA and MA volume ratio under non-uniform mixing was beneficial to methane conversion and syngas production, and the volume ratio of 2:2 reached excellent high-temperature catalytic activity. Therefore, the uniform and non-uniform mixing of different functional catalysts improved the synergistic effect of catalysts and effectively adjusted the combustion performance of methane.