N. A. Kuzin

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.

Thermally Coupled Catalytic Reactor for Steam Reforming of Methane and Liquid Hydrocarbons: Experiment and Mathematical Modeling

An energy-efficient catalytic reactor for producing synthesis gas from methane and liquid hydrocarbons is proposed that is based on the coupling of an endothermic reaction (steam reforming of methane, hexane, or isooctane) and an exothermic reaction (hydrogen oxidation by atmospheric oxygen) in a single cocurrent apparatus. To describe the processes in such an apparatus, a two-dimensional two-temperature mathematical model is developed. It was revealed experimentally and by mathematical modeling that the heat- and mass-transfer coefficients of the gas flow in contact with the catalytically active wall in the exothermic reaction zone considerably affect the thermal conditions in the reactor.

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.

Catalytic heat generating element for autonomous domestic heating systems

New heat-conducting metal porous reinforced catalysts were developed to manufacture a catalytic heat generating element (CHGE) of 25 kW power. The element was subjected to thermophysical, hydraulic and ecological testing. Local temperature and gas flow rates were determined in different places of the outer catalytic bed surface. We have estimated impact of the convective and radiant transfer in total CHGE heat generation. Dynamics of CHGE startup was studied. A prototype of the catalytic water boiler supplied with a CHGE of 25 kW power was manufactured and tested. The boiler provides below yield of toxic waste: CO 5–10 ppm, NOx traces, CH4 10–20 ppm, CO2 10 vol.%, the other gases 89.5 vol.%. CHGE is promising as a device for ecologically safe heat production for household appliances.

Phase Disequilibrium in the Course of an Exothermic Reaction Accompanied by Liquid Evaporation in a Catalytic Trickle-Bed Reactor

Abstractα-Methylstyrene hydrogenation in a fixed catalyst bed is studied experimentally and theoretically for a cocurrent downflow of the gas and liquid. Gas-phase hydrogenation on dry catalyst granules disturbs the liquid–vapor phase equilibrium. A dimensionless parameter related to the Raoult–Dalton law for a liquid–vapor mixture is suggested to characterize phase disequilibrium in the system.

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.

Modeling of critical phenomena for liquid/vapor–gas exothermic reaction on a single catalyst pellet

Abstract Physical mechanisms are discussed and crude mathematical models with lumped parameters are developed, which explain the authors recent experimental data [4] , concerning temperature hysteresis and multiplicity phenomena for α-methylstyrene (AMS) liquid–vapor hydrogenation on a single catalyst pellet. The interplay between endothermic vaporization and exothermic vapor phase reaction is elucidated. The results of this study may help to develop more sophisticated models and theory of hot spots formation and runaway phenomena in trickle-bed reactors.

Catalytic external combustion engine

The operating regimes of a laboratory external combustion engine consisting of a catalytic heater, working cylinder, connection unit with hydroresistance, back pressure unit, and thermochemical recuperator have been studied. An experimental technique that provides an estimate of the power developed by an engine to perform mechanical work has been created. It has been shown that the efficiency can be increased by recuperating the heat of combustion products from the endothermic reaction of the steam that reforms the initial fuel, e.g., propane–butane, into syngas. The effect of the process parameters on an increase in the inner engine efficiency is analyzed. It has been shown that the maximum pressure in the working cylinder has the greatest effect on an increase in the inner efficiency.

Development of a Catalytic Heating System for External Combustion Engines

A catalytic heater design was proposed for an external combustion engine. This design is based on the partial oxidation or autothermal conversion of hydrocarbon fuel to syngas and its further oxidation with heat generation in a radial catalytic reactor integrated with a tubular heat exchanger. The theoretical analysis of operational regimes for a catalytic heater with a thermal power of 25–50 kW was performed with regard to the distribution of gas and the mathematical modeling of processes in a catalyst bed integrated with a heat exchanger, and some estimates were given for the performance of an external combustion engine. The conditions providing a uniform distribution of gas along the length of a radial reactor with suction of a reaction mixture into the catalyst bed were determined. A design of catalytic heating system elements was developed, and some layout solutions that provide a rational mutual arrangement of system components were created.