V. D. Belyaev

Bimetallic Rh-Co/ZrO2 catalysts for ethanol steam reforming into hydrogen-containing gas

The properties of supported bimetallic Rh-Co/ZrO2 catalysts in ethanol steam reforming into hydrogen-containing gas were studied. The particles of Rh-Co solid solutions on the catalyst surface were prepared by the thermal decomposition of the double complex salt [Co(NH3)6][Rh(NO2)6] and the solid solution Na3[RhCo(NO2)6]. It was found that the bimetallic Rh-Co/ZrO2 catalysts exhibited high activity in the reaction of ethanol steam reforming. The equilibrium composition of reaction products was attained at 500–700°C and a reaction mixture space velocity of 10000 h−1.

Copper-cerium oxide catalysts for the selective oxidation of carbon monoxide in hydrogen-containing mixtures: I. Catalytic activity

A series of copper-cerium oxide catalysts were prepared, and their properties toward the reaction of CO oxidation in hydrogen-containing gas mixtures were studied. It was found that the copper-cerium oxide catalysts are stable, active, and selective in this reaction. The conditions under which these catalysts decreased the concentration of CO from 1 to <10−3 vol % in hydrogen containing water vapor and carbon dioxide were determined.

Reduction of nitrogen oxides in diesel exhaust: Prospects for use of synthesis gas

Already commercialized and some of the most promising technologies of nitrogen oxide reduction in automotive diesel exhaust are compared. The Boreskov Institute of Catalysis (Siberian Branch, Russian Academy of Sciences) is developing an advanced method for the selective catalytic reduction of NOx with synthesis gas produced on board by the catalytic conversion of diesel fuel. The activity of the Ag/Al2O3 catalytic system in NOx reduction by H2 + CO admixtures is studied for both a model composition of the exhaust gas and under real diesel operation conditions.

Copper-cerium oxide catalysts for the selective oxidation of carbon monoxide in hydrogen-containing mixtures: II. Physicochemical characterization of the catalysts

The copper-cerium oxide catalysts were characterized using a set of physicochemical techniques including in situ FTIR spectroscopy, XPS, and XRD. It was found that copper segregated on the surface of cerium oxide and its states were labile and dependent on catalyst pretreatment conditions. Copper in a dispersed state was responsible for the reaction of CO oxidation in the presence of H2 on the copper-cerium oxide catalysts. It is likely that this state of copper was composed of two-dimensional or three-dimensional surface clusters containing Cu+ ions.

Effect of internal diffusion on preferential CO oxidation in a hydrogen-rich mixture on a copper-cerium oxide catalyst in a microchannel reactor

The effect of internal diffusion on preferential CO oxidation in a hydrogen-rich mixture on a copper-cerium catalyst in a microchannel reactor was estimated. It was found that the internal effectiveness factor ηCO > 0.8 was reached at a catalytic coating thickness of ∼30 μm.

Diesel fuel pre-reforming into methane-hydrogen mixtures

The pre-reforming of diesel fuel combined with subsequent steam reforming of pre-reforming products integrated with membrane separation of hydrogen is the most promising way of obtaining pure hydrogen for fuel cells. Here, we consider the first part of this problem-diesel fuel pre-reforming. The following commercial nickel-containing catalysts have been tested in the pre-reforming reaction: NIAP-18 (Ni, 15 wt %; CaO, 8 wt %; Al2O3, 74.4 wt %), NIAP-12-05 (Ni, 48 wt %; Cr2O3, 27 wt %), NIAP-07-01 (NiO, 36 wt %), NIAP-07-05 (NiO, 38 wt %; Cr2O3, 12 wt %). A number of new pre-reforming catalysts based on manganese and cobalt compounds have also been examined. The tests have been carried out at pressures of 1, 6, and 15 atm, temperatures of 470–560°C, and gas hourly space velocities of 6000–12000 h−1. The experiments have demonstrated that the nickel-containing catalysts afford a near-equilibrium product composition, while the reaction over the catalysts based on manganese and cobalt compounds yields a nonequilibrium product composition. A mathematical model has been developed for diesel fuel pre-reforming in an adiabatic reactor with a fixed catalytic bed. Model parameters ranging from process kinetics to heat and mass transfer coefficients have been estimated. The results of modeling have been compared to experimental data available from the literature. The potential of the mathematical model has been illustrated by performing calculations for adiabatic reactors with various output capacities.

Catalytic reforming of hydrocarbon feedstocks into fuel for power generation units

The feasibility of realization of the multifuel operation principle, specifically, production of a hydrogen-containing gas from various types of hydrocarbon feedstocks using the same catalyst under similar reaction conditions is considered. The steam reforming of two types of hydrocarbon mixtures, namely diesel fuel satisfying GOST (State Standard) R 52368-2005 (EN 590:2004) and a methane-propane mixture imitating the composition of associated petroleum gas, has been investigated to clarify this issue. These hydrocarbon feedstocks were chosen for the reason that they are universally used as a fuel for various types of power generation units. Experiments have been carried out in a catalytic flow reactor at 250–480°C (for the methane-propane mixture) and 500–600°C (for diesel fuel) and pressures of 1–15 atm using a nickel-containing catalyst (NIAP-18). This catalyst has been demonstrated to ensure conversion of different types of hydrocarbon feedstocks into synthesis gas and methane-hydrogen mixtures usable as a fuel for power generation units based on high-temperature fuel cells and for spark-ignition, diesel, and gas-diesel engines.

Kinetics of low-temperature steam reforming of propane in a methane excess on a Ni-based catalyst

Systematic studies were performed on low-temperature steam conversion or low-temperature steam reforming (LTSR) of propane in an excess of methane on a Ni-based catalyst. The LTSR of the methane–propane mixture is a two-stage process involving the irreversible steam conversion of propane into carbon dioxide and hydrogen and reversible methanation of carbon dioxide. Above ~250°C, the methanation of carbon dioxide is quasi-equilibrium. The rate of propane conversion during the LTSR of the methane–propane mixture is first-order based on propane; its activation energy is ~120 kJ/mol and is almost independent of the methane, carbon dioxide, hydrogen, and steam concentrations. This very simple macrokinetic scheme allows us to correctly describe the experimental data and predict the temperature and flow rate of the mixture at which complete conversion of propane is achieved.

Production of Pure Hydrogen from Diesel Fuel by Steam Pre-Reforming and Subsequent Conversion in a Membrane Reactor

The results of experimental study and mathematical modeling of a fuel processor for the production of pure hydrogen from diesel fuel with a productivity of 600–700 g (H2)/h, consisting of an adiabatic reactor for diesel fuel pre-reforming followed by steam conversion of pre-reforming products in a catalytic Pd–Ag membrane reactor for hydrogen extraction are presented. The membrane reactor consists of 32 membrane modules arranged in 8 sections of 4 modules each. A mathematical model has been developed and two schemes of layout of the modules in the membrane reactor have been simulated. One scheme involves the cross-flow distribution of flue gas and fuel gas reformate to individual modules and leads to overheating of the input modules and cooling of the output modules. The other scheme with the cocurrent distribution of streams, along both the reactant path and the flue gas path, is preferable from the viewpoint of the temperature uniformity of different modules within a section. On the basis of the data obtained, an estimated calculation of the parameters of a power generation unit with a battery of low-temperature fuel cells has been made. For the example considered, the thermal efficiency of the fuel processor is 87%. With an efficiency of the fuel cell battery of 42%, the electrical efficiency of the fuel cell power unit will be 36%.

Gas-Phase Carbonylation of Dimethoxymethane to Methyl Methoxyacetate on Solid Acids: The Effect of Acidity on the Catalytic Activity

The gas-phase carbonylation reaction of dimethoxymethane (DMM) to methyl methoxyacetate on different solid acids was studied. It was established that this reaction was accompanied by the occurrence of a side reaction of DMM disproportionation into dimethyl ether and methyl formate. It was shown that the activity of solid acids in both of the reactions depends on the strength of Brønsted acid sites according to an equation like the Brønsted–Evans–Polanyi–Semenov correlations.