Mn2O3-Na3PO4/TiO2 catalyst with high anti-agglomeration and attrition resistance for fluidized-bed oxidative coupling of methane

The fluidized-bed reactor is a preferred option for the design of an intrinsic-safety oxidative coupling of methane (OCM) process, because it permits such strongly exothermic reaction to proceed isothermally. However, the widely studied Mn-Na 2 WO 4 /SiO 2 catalyst cannot meet the requirements of the fluidized-bed reaction. Ground-breaking fluid catalyst coupling high activity/selectivity with good anti-agglomeration and high attrition resistance represents a grand challenge. Herein, we report an Mn 2 O 3 -Na 3 PO 4 /TiO 2 catalyst (280–355 μm) for the fluidized-bed OCM process, achieving 28.5% CH 4 conversion with 70.1% C 2 -C 3 selectivity at 760 °C for a feed gas of CH 4 /O 2 of 5/1 while remaining unchanged within 16 h test. This catalyst shows significant fluidization behavior under OCM reaction conditions. It is found that TiO 2 nanorods tangle up with each other to form an interpenetrating nano-structure thereby inducing strong mechanical strength and robustness with a low attrition index of only 2.8%. Moreover, high melting-point Na 3 PO 4 and use of TiO 2 support impart the catalyst to good anti-agglomeration because of eradication of formation of the sticky Na 2 Si 2 O 5 and molten Na 2 WO 4 (main cause for agglomeration) encountered in the Mn-Na 2 WO 4 /SiO 2 .