Fabrication of zeolite coatings onto stainless-steel capillary tubes for supercritical hydrocarbon cracking

Abstract

In tubular reactors, the pressure drop can be decreased, and the heat transfer can be enhanced by coating the catalyst on its inner-wall when compared with the performance of fixed-bed types. This study focused on preparing catalyst coatings in capillary tubes for hydrocarbon cracking. The effect of pretreatment processes on the physicochemical properties of the catalyst was studied, and the influence was negligible. In addition, the preparation process was optimized by adjusting the coating method, binder types and contents. The coating prepared using 10 wt% organic binder with an interval coating method showed optimal adhesion. The mass loss was 3.92% after thermal shock and ultrasonic oscillation treatment. During n-dodecane cracking, the gas production rate (GPR) without coating was 8.27%, while that were 31.62% and 65.42% with ZSM-5 and MFI coatings, respectively. Above all, the coatings inhibited coke formation so that the reaction could be continuously performed at 600 °C.