[en] To find a useful and environment-friendly fuel is difficult. Lead and benzene already were replaced by methyl tertiary butylether (MTBE), but this fuel additive too appears to be hazardous for man and the environment. When MTBE will be banned the chances for so-called green petrol (made from biomass) are rising. A brief overview of the developments in the field of fuel additives so far is given

[en] A membrane electrode assembly (MEA) with a novel water management layer (WML) used in proton exchange membrane fuel cell (PEMFC) was prepared. The so called WML, which was located between the carbon paper and the catalyst layer, was a sublayer composed of carbon and hydrophobic PTFE. Various parameters of the WML, including carbon loading, PTFE content and species, sintering time and temperature and pore formers, were investigated in this study. As demonstrated in our experimental results, the performance of the membrane electrode assembly (MEA) PEMFC could be significantly improved by WML in the condition of operation with dry reactive gases. The MEA with the WML exhibited more stable performance than the situation of MEA without WML during a long time running period

[en] Combustion and heat transfer characteristics obtained based co-firing LPG with used engine oils (UEO) in a furnace, are investigated experimentally. In an attempt to assess UEO as a fuel, the UEO-based results are compared with results obtained using two other fuels, namely diesel, and a used cooking oil (UCkO). To ease its admission to the furnace and its subsequent vaporization and combustion, UEO is preheated by allowing it to flow upwardly in a vertical pipe surrounded by hot gases generated from LPG combustion. UEO that reaches the tip of the pipe un-vaporized, spills and hence has the chance to further heatup and vaporize as it exchanges heat with the upwardly flowing LPG combustion gases, in a counter flow process. Runs are divided into three groups based on the mass ratio of the liquid-fuel/LPG and the mass flow rate of the LPG supplied to the furnace. Ranges of these quantities over which UEO qualify as a good fuel and/or good promoter to radiation have been identified.

[en] The production of biofuels from agricultural raw material is attracting great interest for many reasons, among them global warming, oil price hikes, the depletion of oil reserves and the development of new agricultural markets. However, the technologies currently under development are hindered by the fact that available land is limited and by a risk of competition with food crops. In the last few years, research and development efforts have sought to alleviate these limitations by exploring new pathways to convert little-used plant feedstocks to biofuels with better efficiencies. Large-scale research programs concentrating on these new technologies are underway in the U.S. and Europe, with industrial development expected between 2012 and 2020

[en] The mechanism of dimethyl carbonate (DMC) synthesis from methanol and carbon dioxide over monoclinic zirconia has been investigated using in situ infrared spectroscopy. The dissociative adsorption of methanol occurs more slowly than the adsorption of carbon dioxide, but the species formed from methanol are bound more strongly. Upon adsorption, the oxygen atom of methanol binds to coordinately unsaturated Zr4+ cations present at the catalyst surface. Rapid dissociation of the adsorbed methanol leads to the formation of a methoxide group (Zr-OCH3) and the release of a proton, which reacts with a surface hydroxyl group to produce water. Carbon dioxide inserts in the Zr-O bond of the methoxide to form a mondentate methyl carbonate group (Zr-OC(O)OCH3). This process is facilitated by the interactions of C and O atoms in CO2 with Lewis acid-base pairs of sites (Zr4+O2-) on the surface of the catalyst. Methyl carbonate species can also be produced via the reaction of methanol with carbon dioxide adsorbed in the form of bicarbonate species with methanol, a process that results in the transfer of a methyl group to the carbonate and restores a hydroxyl group to the zirconia surface. The decomposition of DMC on monoclinic zirconia has also been investigated and has been observed to occur via the reverse of the processes described for the synthesis of DMC

No abstract available

[en] Solid phosphoric acid (SPA) catalyst is traditionally used in crude oil refineries to produce unhydrogenated motor-gasoline by propene and butene oligomerisation. SPA is also used in High-Temperature Fischer-Tropsch refineries (HTFT) to produce synthetic fuels albeit with a different emphasis. The petrol/diesel ratio of an HTFT refinery is very different from crude refining and it is often necessary to shift this ratio depending on market requirements. The influence of hydration was investigated as a means of improving diesel selectivity. This was achieved by studying SPA over a hydration range of 99-110% H₃PO₄, a temperature range of 140-230 ^oC and using C₃-C₆ model and synthetic FT-derived olefinic feedstocks. A direct correlation was found between the selectivity towards diesel range products and the distribution of the phosphoric acid species viz. H₃PO₄, H₄P₂O₇ and H₅P₃O₁₀. For various olefinic feedstocks, diesel selectivity increased with decreasing catalyst hydration with a maximum around 108% H₃PO₄ for propene oligomerisation. Commercial tests confirmed the increase in diesel selectivity with lowered catalyst hydration. (author)

[en] In this work we report on the vacuum-ultraviolet (VUV) photoionization of small methanol and methanol-water clusters. Clusters of methanol with water are generated via co-expansion of the gas phase constituents in a continuous supersonic jet expansion of methanol and water seeded in Ar. The resulting clusters are investigated by single photon ionization with tunable vacuum ultraviolet synchrotron radiation and mass analyzed using reflectron mass spectrometry. Protonated methanol clusters of the form (CH3OH)nH + (n=1-12) dominate the mass spectrum below the ionization energy of the methanol monomer. With an increase in water concentration, small amounts of mixed clusters of the form (CH3OH)n(H2O)H + (n=2-11) are detected. The only unprotonated species observed in this work are the methanol monomer and dimer. Appearance energies are obtained from the photoionization efficiency (PIE) curves for CH3OH +, (CH 3OH)2 +, (CH3OH)nH + (n=1-9), and (CH 3OH)n(H2O)H + (n=2-9 ) as a function of photon energy. With an increase in the water content in the molecular beam, there is an enhancement of photoionization intensity for methanol dimer and protonated methanol monomer at threshold. These results are compared and contrasted to previous experimental observations

[en] A full three-dimensional, non-isothermal computational fluid dynamics model of a tubular-shaped proton exchange membrane (PEM) fuel cell has been developed. This comprehensive model accounts for the major transport phenomena in a PEM fuel cell: convective and diffusive heat and mass transfer, electrode kinetics, transport and phase change mechanism of water, and potential fields. The model is shown to be able to understand the many interacting, complex electrochemical, and transport phenomena that cannot be studied experimentally. In addition to the new feature of tubular-shaped geometry of PEM fuel cell, this model is used to study the effects of several material parameters on fuel cell performance. Detailed analyses of the temperature distribution inside the tubular cell under various material properties have been conducted and examined. The analysis helped identifying critical parameters and shed insight into the physical mechanisms leading to a fuel cell performance and durability under various material conditions

[en] The continuous oxidation of scrap iron in the presence of a constant CO₂-rich waste gas stream and water is evaluated as a means of sequestering anthropogenic CO₂ as well as generating hydrogen gas and electricity. The stoichiometry of the net reaction, Fe⁰ + CO₂ + H₂O → FeCO₃ + H₂, and assumptions about reaction rates, reactant and product prices/values and overhead costs suggest that CO₂ might be mitigated at a net profit in excess of $30/tonne CO₂. The principle profit center of the process would be hydrogen production, alone providing a gross income of >$160/tonne CO₂ reacted. However, the realization of such fuel cell economics depends on a number of parameters including: (1) the rate at which the reaction can be sustained, (2) the areal and volumetric density with which H₂ and electricity can be produced, (3) the purity of the H₂ produced, (4) the transportation costs of the reactants (Fe, CO₂ and H₂O) and products (FeCO₃ or Fe(HCO₃)₂) to/from the cells and (5) the cost/benefit trade-offs of optimizing the preceding variables in a given market and regulatory environment. Because of the carbon intensity of conventional iron metal production, a net carbon sequestration benefit for the process can be realized only when waste (rather than new) iron and steel are used as electrodes and/or when Fe(HCO₃)₂ is the end product. The used electrolyte could also provide a free source of Fe²⁺ ions for enhancing iron-limited marine photosynthesis and, thus, greatly increasing the CO₂ sequestration potential of the process. Alternatively, the reaction of naturally occurring iron oxides (iron ore) with CO₂ can be considered for FeCO₃ formation and sequestration, but this foregoes the benefits of hydrogen and electricity production. Use of Fe/CO₂ fuel cells would appear to be particularly relevant for fossil fuel gasification/steam reforming systems given the highly concentrated CO₂ they generate and given the existing infrastructure they provide for producing and handling H₂ and/or electricity