Andrey N Zagoruiko

Oxidative destruction of chlorinated hydrocarbons on Pt-containing fiber-glass catalysts

Novel catalysts comprising noble metals (Pt), supported on fiber-glass woven materials demonstrated efficient oxidation of different chlorinated hydrocarbons (chlorobenzene, dichloroethane, dichloropropane,butyl chloride) and industrial mixed chlorinated organic wastes into HCl, CO2 and H2O at moderate temperatures without formation of highly toxic by-products (dioxins, phosgene, polychlorinated hydrocarbons,elemental chlorine). The highest oxidation activity and selectivity was observed for the platinum catalysts produced from fiber-glass supports with increased acidity and with additional introduction of promoting elements (such as Co, Mn and Cu). Long-term tests (more than 100 h) have shown no deactivation of the said catalysts. In combination with competitive catalyst price (due to the extra-low content of Pt--below 0.05% mass) it opens the way for development of highly efficient and feasible technology for utilization and detoxication of various chloro-organic wastes.

Mathematical modelling of Claus reactors undergoing sulfur condensation and evaporation

Abstract The paper is dedicated to the mathematical modelling of Claus reaction performance in the packed catalyst bed under conditions of sulfur condensation and evaporation. The proposed mathematical model accounts for heat and mass transfer between reaction gas and solid catalyst, condensation and evaporation of sulfur, reversible catalyst deactivation by liquid sulfur, Claus reaction reversibility, intraparticle diffusion limitations, heat conductivity of the catalyst bed frame. Reverse-flow operation of the catalyst bed have been investigated. The complex process flow-sheets, comprising two and three catalyst beds with intermediate sulfur condensers, have been simulated. It has been shown, that application of the reverse-flow technique provides increase of process efficiency.

Development of the adsorption-catalytic reverse-process for incineration of volatile organic compounds in diluted waste gases

Abstract Development of adsorption-catalytic reverse-process, based on adsorption of volatile organic compounds (VOC) on the surface of oxide catalyst with periodical incineration of accumulated compounds, applying reverse-flow operation technique is described. Process fundamentals were studied on the base of mathematical model, accounting for heat and mass transfer between gas and catalyst, heat conductivity of the catalyst bed frame, physical adsorption/desorption and irreversible chemisorption of VOC and oxidation of surface compounds. Mathematical modeling showed the high purification efficiency (higher than 99.9%) combined with extremely low energy consumption of the proposed process (less than 1–3 kJ per m 3 of waste gas) in the case of processing of waste gases with low VOC content (below 0.8 g/m 3 ). Results of pilot tests, confirming theoretical results, are presented in the paper.

Application of the nonstationary state of a catalyst surface for gas purification from toxic impurities

Abstract In the present report the results are given of the development of novel catalytic processes based on the forced maintenance of the catalyst in a nonstationary state for deep gas purification from nitrogen oxides (up to 50 mg/m3), SO2 (less than 50 ppm) and organic impurities.

Mathematical modeling of unsteady-state operation taking into account adsorption and chemisorption processes on the catalyst pellet

In this paper the dynamics of hydrocarbons deep oxidation in the catalyst pellet with account of intraparticle diffusion limitations under alternating adsorption stage and oxidation one is studied by means of mathematical modeling. As an example the isopropyl benzene oxidation by oxygen on Cu/Cr/Al oxide catalyst is considered. It is shown that intraparticle diffusion limitation significantly influence both adsorption and oxidation performance. The modeling results demonstrate the existence of the optimal catalyst pellet size, providing the maximum purification efficiency in the adsorption-catalytic process of VOC abatement.

Novel Catalytic Process for Flue Gas Conditioning In Electrostatic Precipitators of Coal-Fired Power Plants

Abstract One of the most important environmental protection problems for coal-fired power plants is prevention of atmospheric pollution of flying ash. The ash particles are typically removed from flue gases by means of electro-static precipitators, for which the efficiency may be significantly increased by lowering the resistance of fly ash, which may be achieved by controlled addition of micro-amounts of sulfur trioxide (SO3) into the flue gases. This paper describes the novel technology for production of SO3 by sulfur dioxide (SO2) oxidation using the combined catalytic system consisting of conventional vanadium catalyst and novel platinum catalyst on the base of silica-zirconia glass-fiber supports. This combination provides highly efficient SO2 oxidation in a wide temperature range with achievement of high SO2 conversion. The performed pilot tests have demonstrated reliable and stable operation, excellent resistance of the novel catalytic system to deactivation, and high overall efficiency of the proposed process. The scale of the plant was equivalent to the commercial prototype; therefore, no further scale-up of the oxidation process is required.

Kinetic investigation and mathematical modeling of oscillation regimes for oxidative dehydrogenation of butene-1

Abstract The investigation included the elaboration of the transient kinetic model of oxidative dehydrogenation of butene-1 to butadiene at Sb–Sn oxide catalyst on the basis of the experimental data and the mathematical modeling of this processes in non-stationary regimes under periodical cycling of initial reagents concentrations. The influence of residence time, amplitude and duration of periodic cycles, ratio of reagents concentrations within the cycle on the process parameters was numerically studied. It has been shown that process performance in unsteady state under forced oscillation of reagents concentration significantly increases the overall yield of butadiene in comparison with the steady-state one. The benefits of the nonstationary process may be realized under technologically acceptable values of process parameters.