Structured ZSM-5 coated SiC foam catalysts for process intensification in catalytic cracking of n-hexane

Abstract

Structured foam catalysts are materials that address the mass and heat transfer limitations in catalytic processes. In this work, ZSM-5 coated silicon carbide (SiC) foams were prepared by a dispersion-based method, resulting in a thin and uniform zeolite layer on the foam support (i.e. ZSM-5/SiC foam catalysts). A comparative study of catalytic cracking of n-hexane was studied over ZSM-5/SiC foam and ZSM-5 pellet catalysts at space velocities of 4–40 h⁻¹, showing the improved n-hexane conversion, total selectivity to C₂–C₄ olefins and anti-deactivation performance, especially at the relatively high space velocities (>10 h⁻¹), achieved by the ZSM-5/SiC foam catalysts. The yield of light olefins obtained by the ZSM-5/SiC foam catalyst (with 45 ppi cell density) was almost five times higher than the yield obtained by the conventional ZSM-5 pellets. A detailed analysis revealed that the specific surface area of SiC foams has a significant effect on the coating quality, and hence, the catalytic performance in the cracking reaction.