Bifunctional Cobalt Catalysts for the Fischer–Tropsch Synthesis of Low-Pour-Point Diesel Fuel: From Development to Implementation: 2. Optimization of the Catalyst Component Composition

The effect of the content of metallic (Co–Al₂O₃/SiO₂ catalyst) and acidic components (ZSM-5 zeolite in H-form) on the properties of a bifunctional catalyst for the integrated synthesis of low-pour-point diesel fuel by the Fischer–Tropsch method has been studied. The catalysts in the form of a composite mixture with a binder (boehmite) have been characterized by XRD, BET, and TPR methods. The tests are conducted in a fixed-bed flow reactor at a pressure of 2.0 MPa, a temperature of 240°C, and a gas space velocity of 1000 h^–1. The activity and selectivity of catalysts and the fractional and hydrocarbon compositions of products as a function of the ratio of components have been compared. It has been found that the synthesis productivity with respect to С₅₊ hydrocarbons and selectivity to products of the С₁₁–C₁₈ diesel fraction with a high content of isomeric products correlate with the ratio of metallic and acidic components in the catalyst composition. The catalyst recommended for use in diesel fuel production has a composition with a ratio of metallic and acidic components of 1.17.