Oxidation of methane over platinum in a solid proton-conducting electrolyte cell

Studies of the complete oxidation of methane on a Pt electrode-catalyst in the cell with a solid proton-conducting electrolyte (CH₄ + O₂, Pt ¦ SrCe_0.92Dy_0.08O₃ ¦ Pt, H₂O + N₂) were carried out. The non-Faradaic effect of electrochemical hydrogen pumping on the rate of methane oxidation has been demonstrated. The induced change in the reaction rate at anodic polarization of a Pt electrode-catalyst was over two orders of magnitude higher than the rate of hydrogen pumping from the reaction zone through the electrolyte.     

Thermomechanical correction to the drag force on a sphere and a cylinder moving in HeII

The drag force on a sphere and a cylinder moving in HeII is considered on the basis of the full system of the two-fluid dissipative hydro-dynamical equations. It is shown, that due to the thermomechanical effect in superfluid there exists a specific correction to the drag force on a body. The value of this thermomechanical correction F has the order of the ratio1 _T/R or1 _T ² /R² (R is the size of the body, and1 _T is the length of the formation of the convective heat flow). The value of F grows at low temperatures, where1 _T is proportional to the characteristic time of the phonon-roton scattering process, and in the region near the -point, where1 _T has the same temperature dependence as the order parameter correlation length 1_T (T–T)^–2/3. The effects under discussion can be investigated experimentally by measurements of the mobility of small objects. A comparison is given with the data of the mobility of positive and negative ions in HeII near the -point.     

Synthesis gas production by steam reforming of ethanol

A two-layer fixed-bed catalytic reactor for syngas production by steam reforming of ethanol has been proposed. In the reactor, ethanol is first converted to a mixture of methane, carbon oxides and hydrogen over a Pd-based catalyst and then this mixture is converted to syngas over a Ni-based catalyst for methane steam reforming. It has been shown that the use of the two-layer fixed-bed reactor prevents coke formation and provides the syngas yield closed to equilibrium.     

Transformation of CH4 and liquid fuels into syngas on monolithic catalysts

Active components comprised of fluorite-like Ln_x(Ce_0.5Zr_0.5)_1−xO_2−y (Ln = La, Pr, Sm) and perovskite-like La_0.8Pr_0.2Mn_0.2Cr_0.8O₃ mixed oxides and their composites with yttria-doped zirconia (YSZ) promoted by precious metals (Pt, Ru) and/or Ni were supported on several types of heat-conducting substrates (compressed Ni-Al foam, Fecralloy foil or gauze protected by corundum layer, Cr-Al-O microchannel cermets, titanium platelets protected by oxidic layer) as well as on honeycomb corundum monolithic substrate. These structured catalysts were tested in pilot-scale reactors in the reactions of steam reforming of methane, selective oxidation of decane and gasoline and steam/autothermal reforming of biofuels (ethanol, acetone, anisole, sunflower oil). Applied procedures of supporting nanocomposite active components on monolithic/structured substrates did not deteriorate their coking stability in real feeds with a small excess of oxidants, which was reflected in good middle-term (up to 200 h) performance stability promising for further up-scaling and long-term tests. Equilibrium yield of syngas at short contact times was achieved by partial oxidation of decane and gasoline without addition of steam usually required to prevent coking. For the first time possibility of successive transformation of biofuels (ethanol, acetone, anisole, sunflower oil) into syngas at short contact times on monolithic catalysts was demonstrated. This was provided by a proper combination of active component, thermal conducting monolithic substrates and unique evaporation/mixing unit used in this research.     

Bimetallic Au-Cu/CeO2 catalyst: Synthesis,structure, and catalytic properties in the CO preferential oxidation

The preparation of bimetallic Au-Cu catalysts via the decomposition of the double complex salt [Au(en)₂]₂[Cu(C₂O₄)₂]₃ · 8H₂O is considered. It is found that this method of preparation allows us to selectively obtain Au_0.4Cu_0.6 solid solution nanoparticles on the surface of a support. The composition of the particles corresponds to the stoichiometry of the double complex salt. The properties of bimetallic Au-Cu/CeO₂ catalyst and monometallic Au/CeO₂ and Cu/CeO₂ catalysts were studied during the preferential oxidation of CO in a mixture containing CO₂ and H₂O. The experiments were performed in a catalytic flow system within a temperature range of 50–250°C with a mixture of the following composition, vol %: CO, 1; O₂, 0.6; H₂O, 10; CO₂, 20; H₂, 60; and the balance, He. The weight hourly space velocity (WHSV) was 276000 cm³/(g h). The bimetallic catalyst made it possible to oxidize a considerably larger amount of CO with higher selectivity with CO₂ and H₂O in the mixture, relative to the monometallic catalysts. The preferential oxidation of carbon monoxide in the presence of hydrogen is a promising method for the deep purification of hydrogen-containing gas mixtures in order to remove carbon monoxide. The purified hydrogen-containing gas can be used to feed portable power units based on low-temperature proton-exchange membrane fuel cells, for the synthesis of ammonia, and for hydrogenation in fine organic synthesis.     

Thermodynamic analysis of a solid oxide fuel cell power system with external natural gas reforming

A thermodynamic analysis of a solid oxide fuel cell power system is performed using conditions of thermodynamic equilibrium in a prereformer of natural gas to synthesis gas and a solid oxide fuel cell battery. It is shown that a thermally coupled steam reformer of natural gas provides a significantly higher efficiency of conversion of fuel energy to electric energy than other types of reformers.     

Numerical simulation of external heat exchange in a gas-electric glass-making furnace with a horseshoe flame arrangement

Anumerical simulation of the external heat exchange in a gas-electric glass-making furnace is examined. It is shown that the intensity of additional electric heating (AEH) of the glass mass affects the normal operation of the furnace. Examples of the calculation of the parameters of heat exchange as a function of the furnace productivity and AEH are presented.     

Synthesis gas generation on-board a vehicle: Development and results of testing

The present work is focused on the development of energy-efficient internal combustion engines with minimized CO, CO₂, CH and NO_x emissions. In frame of this concept, a method for hydrogen-rich gas generation onboard a vehicle and, in particular, its application as an additive to the engine fuel was suggested and tested experimentally. For practical realization of the method, the catalysts for hydrocarbon fuel reforming to synthesis gas were created, compact under-hood mounted synthesis gas generator was designed, and integrated ICE-synthesis gas generator control system was developed. The tests proved fuel economy in city cycle and considerable decrease of CO, CO₂, CH and NO_x emissions. The prospects of the technology for the development of energy-efficient environmentally benign engines are analyzed.     

Catalysts for hydrogen production in a multifuel processor by methanol,dimethyl ether and bioethanol steam reforming for fuel cell applications

Methanol, dimethyl ether and bioethanol steam reforming to hydrogen-rich gas were studied over CuO/CeO₂ and CuO–CeO₂/γ-Al₂O₃ catalysts. Both catalysts were found to provide complete conversion of methanol to hydrogen-rich gas at 300–350 °C. Complete conversion of dimethyl ether to hydrogen-rich gas occurred over CuO–CeO₂/γ-Al₂O₃ at 350–370 °C. Complete conversion of ethanol to hydrogen-rich gas occurred over CuO/CeO₂ at 350 °C. In both cases, the CO content in the obtained gas mixture was low (<2 vol.%). This hydrogen-rich gas can be used directly for fuelling high-temperature PEM FC. For fuelling low-temperature PEM FC, it is needed only to clean up the hydrogen-rich gas from CO to the level of 10 ppm. CuO/CeO₂ catalyst can be used for this purpose as well. Since no individual WGS stage, that is necessary in most other hydrogen production processes, is involved here, the miniaturization of the multifuel processor for hydrogen production by methanol, ethanol or DME SR is quite feasible.