Development of an Active and Mechanically Stable Catalyst for the Oxidative Coupling of Methane in a Gas–Solid Vortex Reactor

Abstract

The high gas–solid slip velocity and the resulting intensified heat and mass transfer make gas–solid vortex reactors (GSVR) a promising reactor technology for the oxidative coupling of methane (OCM). The short gas residence time and high solid velocity in the GSVR require a highly active catalyst with strong attrition resistance. Conventional Sr/La2O3 catalysts possess sufficient activity; however, these materials lack mechanical strength. In this study, a novel active and mechanically strong catalyst is developed by supporting a conventional Sr/La2O3 OCM catalyst on a porous SiC support. The Sr–La–O/SiC catalyst shows a very high activity for the OCM in a fixed-bed lab-scale reactor. More importantly, the Sr–La–O/SiC catalyst displays high attrition resistance in standardized attrition tests and forms a stable rotating fluidized bed in the GSVR during a hot flow experiment at 946 K for more than 1 h. Shape characterization of the catalyst particles collected from a hot flow experiment suggests friction rather than fragmentation as the dominant attrition mechanism. Finally, the Sr–La–O/SiC catalyst was successfully tested under reactive conditions in the GSVR at 1080 K, showing a methane conversion of around 6% and a C2 yield of 2% for an estimated space-time of 0.25 kgcat s molCH4–1.