Catalytic Cracking of Cyclohexane and 1-Hexene Mixtures on Mono-, Bi-, and Tri-Zeolite Catalysts

Abstract

The effects of temperature (540–640°C), weight hour space velocity (1.0–7.0 h^–1), and steam : raw material ratios (0–2.5) on the yield of C₂–C₄ olefins, conversion, and octane characteristics in the cracking of a mixture of model hydrocarbons (cyclohexane and 1-hexene) were studied. The influence of the structure of zeolites in mono-, bi-, and tri-zeolite catalysts on the distribution of cracking products was examined. It was found that the combination of catalyst components in bi- and tri-zeolite systems makes it possible to increase the efficiency of the consecutive cracking of hydrocarbons (C₆–C₁₂ → C₄–C₈ → C₃–C₆ → C₂–C₄) according to the following reaction scheme: matrix → ZSM-5 → FER. The maximum total yield of C₂–C₄ olefins (50.2 wt % at a conversion of 75.5%) was achieved with the use of a bi-zeolite catalyst of ZSM-5 + FER.