Abstract
Crude oil upgrading under methane has been reported to be an economically and environmentally promising process, while the advantageous effect of methane beyond a reactant is not fully explained. In this work, the catalytic performances, physicochemical properties and regenerability of used catalysts after crude oil upgrading under methane and nitrogen are investigated by n-butylbenzene model compound studies, catalyst characterizations and density functional theory calculations. Comparing to nitrogen, methane exhibits a protective effect on the charged catalyst despite the limited conversion, leading to better product quality and catalyst stability. This protective effect is attributed to the interaction between methane and catalytic active sites, which mainly occurs in the internal pores of the zeolitic catalyst support, resulting in unique coke distribution and inhibition of metal deposition. The interactive role of methane beyond a reactant, which is previously underestimated, is suggested to be critical for better performances of catalysts in relevant reaction processes.