Fischer–Tropsch Synthesis over Bifunctional Catalysts Based on HBeta Zeolite

A number of catalysts were synthesized from a composite mixture consisting of a metal component (specifically, a Co–Al2O3/SiO2 catalyst in an amount of 20–40% for the synthesis of long-chain hydrocarbons), an acid component (Beta zeolite in the H-form, 20–50%), and a binder (boehmite). The catalysts were characterized by XRD, low-temperature argon adsorption/desorption, and TPR, and tested in Fischer–Tropsch synthesis at 2.0 MPa, 240°C, and GHSV 1000 h–1. The activity and selectivity of the catalysts were compared, and the composition of the synthetic products was investigated. The content of the zeolite component was found to be critical to the cracking and isomerization activity of the catalysts. It was further shown that the ratio between the active components correlates with the C5+ productivity and the selectivity towards fuel-range hydrocarbons. The catalysts with Co–Al2O3/SiO2 to HBeta ratios of 0.75 and 1.3 were found to be optimal for high-performance synthesis of gasoline-range (C5–C10) and diesel-range (C11–C18) hydrocarbons, respectively.