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A cobalt Fischer–Tropsch synthesis catalyst supported on titania-doped silicon carbide is synthesized and comprehensively studied by a number of physicochemical means. The dynamics of the behavior and deactivation of the catalyst was studied after its stable operation for 1500 h during continuous experimental resource testing with a periodic change in the syngas flow rate and pressure and the process temperature. This catalyst has two types of active sites, on which products with different Schulz–Flory distribution parameters form. Depending on the process regime, the effective formation of soft waxes or more high-molecular-weight products is possible.

A cobalt catalyst supported on titania-doped silicon carbide for the Fischer – Tropsch synthesis was synthesized and comprehensively studied using various physicochemical methods. The dynamics of behavior and deactivation of the catalyst, which showed a stable operation for 1500 hours, was studied in a continuous pilot-plant lifecycle test with periodic variation of flow rate, syngas pressure and process temperature. This catalyst has two types of active sites on which products with different parameters of the Schulz – Flory distribution are formed. Depending on the process mode, the efficient formation of «soft waxes» or products with a higher molecular weight can occur.

On the basis of analysis of experimental data on the temperature in a reactor for Fischer–Tropsch synthesis, a method for prediction of loss in thermal stability of such a reactor by extrapolating the reactor temperature in time with the use of the first-order and second-order time derivatives of experimental data on this temperature has been developed. Since, in this case, the calculation of derivatives is an incorrect procedure because of the rapid changes in the reactor temperature and the accidental errors in its measurement, this problem was solved using the Tikhonov stabilizing-functional method. An integro-differential equation of calculating the first-order and second-order time derivatives of experimental temperatures of the reactor, providing a minimum of the stabilizing functional, has been derived. The possibility of predicting the behavior of the temperature in a reactor under the conditions of loss in its thermal stability was demonstrated through the comparison of calculation and experimental data on the reactor temperature. The method proposed can be used for development of an automated system for control over the working conditions of a reactor for Fischer–Tropsch synthesis for prevention of its thermal explosion.

The productivity of Fischer-Tropsch reactors is determined by the efficiency of heat and mass transfer processes inside the catalyst granules. To reduce the diffusion resistance the granules base is made from ceramic highly porous material. The porous structure of the granules causes a discrete arrangement of cobalt metallic microparticles whose size can reach tens of microns. Cobalt particles are the active centres on which the synthesis reactions are realized. The distance between these active centres significantly exceeds their characteristic size and the homogeneous model for heat and mass transfer is incorrect. In our paper a mathematical model of heat and mass transfer processes in a porous spherical granule with localised active centres is proposed. The heat of the exothermic synthesis reaction is removed from the surface of the granule by heat transfer into the synthesis gas stream washing the granule. The components of the synthesis gas enter to the granule surface as a result of mass transfer. On the basis of the mean-field approach the values of the temperature and concentration of the synthesis gas components at the active centres inside the granule were determined. In the reactor tube, where the catalyst granules are placed, there is a critical temperature. The excess of the critical temperature leads to a thermal explosion, i.e. a substantial overheating of the active centres. In this case, the surface of the catalyst granule is superheated slightly. The principal difference between the homogeneous and heterogeneous models in catalytic reactions is discussed. We analysed influence of the temperature inside the reactor tube, size of the granule, and coefficient of thermal conductivity on the thermal stability of the granule.

Composite pelletized catalysts for higher one-pass conversion and productivity in the Fischer–Tropsch process are reported. The introduction of aluminum metal powder as a thermal conductor leads to the formation of a new family of composite pelletized catalysts, very different from reference systems. In particular, these catalysts retain high activity and C5+ selectivity at increasing gas-hour space velocities of up to 5,000 h−1. The productivity of these composite catalysts increases almost fourfold for fivefold GHSV increase. Composite catalysts with different types of active cobalt (conventional, introduced by impregnation, or skeletal) show similar values of one-pass conversion and productivity but give different fractional and group composition of liquid hydrocarbon products. Testing of these highly productive catalysts in reactors with different aspect ratios showed that high productivity and one-pass conversion can be achieved in industrial-size units, where feasible liquid yield of up to 140 barrels per million standard cubic feet (MMSCF) of natural gas can be reached.

One of the most important problems in the synthesis of carbon nanotubes is the problem of controlling their morphology, namely: length, aspect ratio, alignment, etc. Catalytic synthesis of carbon nanotubes in a suspended bed reactor allowed to study the possibilities of controlling the growth of nanotubes by introducing a certain amount of water vapor and carbon-containing materials in the reaction zone. The synthesized long carbon nanotubes were studied by Raman spectroscopy, transmission and scanning electron microscopy. We found that water concentration influences both yield and the structure of nanotubes. It is shown that the yield of centimeter-long nanotubes can be maximized at an optimum H2O/C ratio, while deviations dramatically change morphology and thickness of the nanotubes.