A Bifunctional Cobalt Catalyst for the Fischer–Tropsch Synthesis of Low Pour-Point Diesel Fuel, from Development to Implementation. Part 3: Experience from Creating an Industrial Technology of Preparation

Abstract

The results of testing the technology of preparing a bifunctional cobalt catalyst used to synthesize hydrocarbons from CO and H₂, obtained by extruding a mixture of Co-Al₂O₃/SiO₂ catalyst and HZSM-5 zeolite powders with a binder (boehmite) under industrial conditions (two batches of 50 kg each) are presented. The catalyst technology is tested on equipment at the Ishimbay Specialized Chemical Catalyst Plant (Russia). The resulting samples of industrial catalyst are studied via XRF, H₂-TPR, and DTG, and tested in the synthesis of hydrocarbons from CO and H₂ at 250°C, a pressure of 2.0 MPa, and a gas hourly space velocity of 1000 h⁻¹. It is shown that the bifunctional cobalt catalyst for producing low pour-point diesel fuel under industrial conditions allows properties of the catalyst obtained under laboratory conditions to be reproduced. The technology for obtaining the catalyst can be recommended for the production of industrial batches. It is found that changing the conditions of the catalyst’s heat treatment and the presence/absence of a peptizer and pore former do not appreciably reduce the productivity of C₅₊ hydrocarbons. The amount of the diesel fraction in C₅₊ products obtained on industrial catalyst samples remains at the same level as on the laboratory catalyst sample. At the same time, the low-temperature properties of diesel fuel obtained on all catalyst samples have similar values. The best low-temperature properties of diesel fuel are obtained on an industrial sample synthesized without a peptizer and a pore-forming component. The cloud point and the point of liquid loss are −16 and −24, respectively.