Catalytic Conversion of Canola Oil over Potassium-Impregnated HZSM-5 Catalysts: C2−C4 Olefin Production and Model Reaction Studies

Abstract

The influence of catalyst acidity, reaction temperature, and canola oil space velocity on the conversion of canola oil was evaluated using a fixed-bed microreactor at atmospheric pressure at reaction temperatures and space velocities (WHSV) in the ranges 400−500 °C and 1.8−3.6 h-1, respectively, over potassium-impregnated HZSM-5 catalysts. These catalysts were thoroughly characterized using XRD, N2 adsorption measurements, 1H NMR, TPD of NH3, FT-IR, and model compound reactions. Also, conditions for the production of the maximum yield of C2−C4 olefins from canola oil were determined. The incorporation of potassium into HZSM-5 catalyst resulted in both the dilution and poisoning of Bronsted and total acid sites. These acidity changes only severely affected the acid catalyzed reactions, such as oligomerization and aromatization, and resulted in drastic modifications in product distribution. The maximum C2−C4 olefin yield of 25.8 wt % was obtained at 500 °C and 1.8 h-1 space velocity with catalyst K1 of rela...