Co-Ru/γ-Al2O3 Catalyst Modified With ZrO2 for Fischer-Tropsch Synthesis

Abstract

Using an incipient impregnation method, a Co-Ru bimetallic catalyst was prepared. The effects of the ZrO2 modification of support on heavy hydrocarbon synthesis were investigated in a fixed-bed reactor. The results indicated that the ZrO2 modification could block defects of γ-Al2O3 crystal lattice, weaken the interaction between support and Co, and hinder or prevent the formation of cobalt aluminate. Zr reacted with Co to form the Co-Zr species, which is easily reduced under lower temperature. It caused an increase in the amount of easily reducible Co species and a decrease in the amount of uneasily reducible Co species. Then the reduction extent of cobalt-based catalyst was raised under the typical reduction condition. Meanwhile, support of γ-Al2O3 was modified with ZrO2, and the interface of Co-ZrO2 formed. The Co-ZrO2 interface led to an increase of the intensity of the bridge-form CO adsorption, which CO facilitates to be dissociated. At H2/CO molar ratio in feed 2.0, 503 K, 1.5 MPa, and 800 hr−1, the catalyst exhibited better catalytic performance. The CO conversion was 93.27%, the C5 + selectivity was 82.56%, and the chain growth factor was 0.81.