V. Z. Mordkovich

Phase composition, physicochemical and catalytic properties of cobalt–aluminum–zeolite systems

The phase composition and physicochemical and catalytic properties of three samples of cobalt–aluminum–zeolite systems were studied. The catalytic properties of the systems are related to the application of a highly porous acidic support and the presence of cobalt oxide crystallites of an optimal size (6–12 nm). The occurrence of an efficient heat-conductive spatial net formed by metallic aluminum particles is also important for catalytic performance.

Effect of rhenium on Fischer–Tropsch synthesis in the presence of cobalt–zeolite catalysts

The effect of the method of introduction and content of rhenium on the basic performance parameters of Fischer–Tropsch synthesis and the composition of the resulting hydrocarbons in the presence of cobalt catalysts supported on a zeolite-containing composite has been determined.

Effect of the mode of introduction of cobalt into a composite zeolite catalyst on the product composition of Fischer-Tropsch synthesis

It has been shown that the mode of introduction of cobalt into a granular composite catalyst based on an HB zeolite has an effect on the characteristics and composition of the Fischer-Tropsch synthesis products. It has been found that the introduction of skeletal cobalt into the composition of the catalyst by wet mixing provides a higher productivity with respect to C5+ hydrocarbons (HCs). A catalyst prepared by impregnation of zeolite-containing granules has been found to exhibit the highest selectivity, while the highest specific activity has been revealed for a composite containing a Co/HB impregnation powder catalyst introduced by wet mixing. It has been shown that high specific activity does not provide high productivity in the formation of C5+ HCs and, to achieve a high productivity of the catalyst, it is necessary to form granules exhibiting heat conductivity and having a developed porous system for optimization of heat and mass transfer.

Role of zeolite in the synthesis of liquid hydrocarbons from CO and H2 on a composite cobalt catalyst

It is found that the main role of zeolite in Fischer–Tropsch synthesis on a composite Co catalysts is to reduce the average molecular weight of hydrocarbons produced from CO and H2 on acid sites. Secondary transformations of hydrocarbons on zeolites seem to occur via a carbocation mechanism. The total composition of synthesis products depends on the zeolite properties and the mutual arrangement of zeolite and cobalt active sites. It is shown that in some cases, introducing H-form zeolite into the Co catalysts for Fischer–Tropsch synthesis increases the productivity and the selectivity to synthetic oil and lowers the selectivity to methane.

Fischer–Tropsch synthesis with cobalt catalyst and zeolite multibed arrangement

The role of zeolite in transformations of hydrocarbons produced from CO and H2 over a Fischer–Tropsch cobalt catalyst under the conditions of multibed arrangement of the cobalt catalyst and the zeolite has been determined. Hydrocarbon conversion over the HBeta zeolite occurs via the bimolecular mechanism, as evidenced by a low methane yield and a high yield of unsaturated gaseous and liquid hydrocarbons. The conversion over the CaA zeolite obeys the unimolecular mechanism, as evidenced by the formation of increased amounts of methane and saturated gaseous C2–C4 hydrocarbons.