Yu. I. Amosov

Bioethanol as a promising fuel for fuel cell power plants

The catalytic reaction of steam reforming of bioethanol for the production of a hydrogen-containing gas in a temperature range from 300 to 700°C is studied. Copper-, nickel-, cobalt-, platinum-, and rhodium-containing catalysts supported on different substrates, including metal grids, are tested. Comparative analysis of the methods of bioethanol processing to a hydrogen-enriched gas for feeding high-temperature proton-exchange polymer electrolyte membrane fuel cells is performed.

Selective methanation of CO in the presence of CO2 in hydrogen-containing mixtures on nickel catalysts

The screening of commercial nickel catalysts for methanation and a series of nickel catalysts supported on CeO2, γ-Al2O3, and ZrO2 in the reaction of selective CO methanation in the presence of CO2 in hydrogen-containing mixtures (1.5 vol % CO, 20 vol % CO2, 10 vol % H2O, and the balance H2) was performed at the flow rate WHSV = 26000 cm3 (g Cat)−1 h−1. It was found that commercial catalytic systems like NKM-2A and NKM-4A (NIAP-07-02) were insufficiently effective for the selective removal of CO to a level of <100 ppm. The most promising catalyst is 2 wt % Ni/CeO2. This catalyst decreased the concentration of CO from 1.5 vol % to 100 ppm in the presence of 20 vol % CO2 in the temperature range of 280–360°C at a selectivity of >40%, and it retained its activity even after contact with air. The minimum outlet CO concentration of 10 ppm at 80% selectivity on a 2 wt % Ni/CeO2 catalyst was reached at a temperature of 300°C.

Effect of preparation procedure on the properties of CeO2

The effect of preparation procedure on the physicochemical and catalytic properties of CeO2 was studied. Differences in the electronic and structural characteristics of CeO2 depending on preparation procedure and treatment temperature were found using X-ray diffraction analysis, transmission electron microscopy, UV-visible electronic spectroscopy, and X-ray photoelectron spectroscopy. With the use of the temperature-programmed reaction with CO, it was demonstrated that CeO2 samples with a high concentration of point defects—oxygen vacancies caused by the presence of Ce3+—were characterized by an increased mobility of bulk oxygen. The samples of CeO2 with a high concentration of structural defects—micropores of size 1–2 nm and stepwise vicinal faces in crystallites—exhibited a high catalytic activity in the reaction of CO oxidation.

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.

Synthesis of aluminum oxides from the products of the rapid thermal decomposition of hydrargillite in a centrifugal flash reactor: II. Physicochemical properties of the products obtained by the centrifugal thermal activation of hydrargillite

A variety of physicochemical methods were used to characterize the product of the rapid thermal decomposition of hydrargillite in a centrifugal flash reactor under the following conditions: the average particle size of the reactant, 80–120 μm; the temperature of the solid heating surface (plate or cylinder), 300–700°C; hot-zone residence time, ∼1 s; transfer of the product to the cooled zone of the reactor. The composition of the product and the extent of decomposition of hydrargillite were determined as a function of the processing temperature. The centrifugal thermal activation (CTA) of hydrargillite affords an X-ray-amorphous, highly reactive product with a developed surface and a disordered and inhomogeneous porous structure. This structure is capable of forming different modifications of aluminum hydroxide and oxide. The properties of the CTA product are compared with the properties of the earlier reported hydrargillite rapid decomposition products obtained using a gaseous heat-transfer agent (thermochemical activation product) or a fluidized bed of a granular heat-transfer agent (thermal dispersion product).

Synthesis and physicochemical characterization of palladium-cerium oxide catalysts for the low-temperature oxidation of carbon monoxide

The effect of CeO2 preparation procedure on the electronic and structural states of the active component of Pd/CeO2 catalysts and their activity in the low-temperature reaction of CO oxidation was studied. The following two nonequivalent states of palladium were detected in the catalysts having low-temperature activity using XPS and IR spectroscopy: Pd0(Pdδ+) as the constituent of a palladium-reduced interaction phase and Pd2+ as the constituent of a palladium-oxidized interaction phase PdxCeO2 −δ. It was found that the procedure used for preparing a CeO2 support considerably affected the formation of these phases and quantitative ratios between them. It was demonstrated that the palladium-oxidized interaction phase was responsible for low-temperature activity, whereas the palladium-reduced interaction phase was responsible for activity in the region of medium and high temperatures.

Use of syngas as an auto fuel additive: State of the art and prospects

A method for the production of a hydrogen-rich gas on board a vehicle was suggested and driving- and bench-tested for application in studies on energy-efficient internal combustion engines with minimum CO, CO2, CH, and NOx emissions. The generated gas is further added to the main fuel fed to the engine. Catalysts for hydrocarbon fuel conversion to syngas were developed. A compact on-board syngas generator mounted under the motor hood and a generator control system adapted to the engine control system were designed. It was shown experimentally that the suggested solution allows a reduction of 13–40% in the fuel rate depending on the operating mode under the urban cycle conditions and considerably decreases the release of CO, CO2, and NOx. Prospects for the applications of this technology for creating ecologically clean engines were assessed.

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.

Thermochemical conversion of fuels into hydrogen-containing gas using recuperative heat of internal combustion engines

The problem of the thermochemical recuperation of heat from the exhaust gases of internal combustion engines (ICEs) as a method of increasing of the efficiency of fuels has been considered. The thermodynamic analysis of thermochemical recuperation conditions was performed, and maximum efficiency conditions were determined. Catalysts for the steam conversion of oxygen-containing fuels into syngas were developed, and the Co-Mn/Al2O3 catalyst was shown to be the most promising. The model of a thermochemical heat recuperation system was developed and manufactured, and its bench tests in the conversion of alcohols were performed using the simulated exhaust gases from a heating device. Mathematical models for calculating units of the heat recuperation system were developed. A recuperation system was manufactured and tested in the ICE-free and ICE-integrated variants. Based on the test results, the equivalent fuel consumption characteristics of a recuperative ICE was revealed to decrease by 11–22% depending on its load with a decrease in the concentration of hazardous emissions by 8–12 times for CO, 2–3.5 times for CH, and 18–25 times for NOx.

Catalysts for the Conversion of Hydrocarbon and Synthetic Fuels for Onboard Syngas Generators

The use of syngas derived on board a vehicle as a supplement to the main fuel fed to engines ensures engine operation using dilute fuel mixtures. This leads to a decrease in emission toxicity and an increase in the fuel efficiency of the engine. The preparation of new types of efficient catalysts for the conversion of hydrocarbon and synthetic fuels for onboard syngas generators requires the use of new approaches to the design of catalysts not only as catalytically active material, but also as a structural component of a chemical reactor. We prepared and tested a set of catalysts for the conversion of hydrocarbons, i.e., natural gas, diesel and biodiesel fuels, biofuels, and alcohols (ethanol, methanol) to syngas. Primary supports for the catalysts were metals grids and porous tapes; secondary supports were oxides of aluminum and magnesium deposited on or sintered to a primary support. The catalysts exhibited high thermal stability and mechanical strength, and were characterized by the conformity of the coefficients of thermal expansion of the support material and the catalytically active bed. The catalysts can be used as structural components of reactors and as a basis for the preparation of monolithic blocks and planar components of radial and planar reactors. The developed catalysts were subjected to laboratory and bench tests and examined as components of onboard generators of vehicles.