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Sample records for direct methanol full

  1. Direct Methanol Fuel Cell, DMFC

    Directory of Open Access Journals (Sweden)

    Amornpitoksuk, P.

    2003-09-01

    Full Text Available Direct Methanol Fuel Cell, DMFC is a kind of fuel cell using methanol as a fuel for electric producing. Methanol is low cost chemical substance and it is less harmful than that of hydrogen fuel. From these reasons it can be commercial product. The electrocatalytic reaction of methanol fuel uses Pt-Ru metals as the most efficient catalyst. In addition, the property of membrane and system designation are also effect to the fuel cell efficient. Because of low power of methanol fuel cell therefore, direct methanol fuel cell is proper to use for the energy source of small electrical devices and vehicles etc.

  2. Evaluation of silver as a miniature direct methanol full cell electrode

    Science.gov (United States)

    Gao, Yong; Kong, Xiangxing; Munroe, Norman; Jones, Kinzy

    Miniature direct methanol fuel cells (DMFCs) and direct hydrogen fuel cells are promising candidates for future polymer electrolyte membrane (PEM) based micro-power sources. Currently, most miniature DMFCs are developed using a silicon based microelectromechanical system (MEMS) technique, which requires complex and precise processing. Low temperature cofire ceramic (LTCC) technology offers an attractive alternative for a ceramics MEMS construction, allowing the integration of high density interconnect and embedded electronic components with microchannels and hermetic cavities from the meso- to the microscale. Silver is a major metallization source for LTCC, which can be fabricated in a range of configurations, from a solid hermetic layer to a porous open structure with microchannels that can easily be integrated into the structures. Silver based LTCC provides an ideal technology for the fabrication of an integrated fuel cell into a high density ceramic-based microelectronic assembly. A silver electrode was evaluated in a simulated DMFC operating environment and found to exhibit good corrosion resistance and chemical stability, essential properties for electrode systems. Potentiodynamic analysis of a catalyzed silver electrode (prepared by thermal decomposition of a Pt/Ru resinate) revealed excellent corrosion resistance under anodic and cathodic DMFC operating conditions. The Pt/Ru catalyst on the silver electrode enhanced the methanol oxidation reaction (MOR) as well as oxygen reduction reaction (ORR) as compared with similar reactions on carbon electrodes. The potential at which methanol is oxidized was lower than the silver oxidation potential, which served to protect the silver electrode. The determination of a contact angle of 30° on the silver electrode indicated wettability, which is deleterious for its application in DMFCs. Nevertheless, the results of good corrosion resistance derived from this investigation as well as the high electrical and thermal

  3. Selectivity of Direct Methanol Fuel Cell Membranes

    Directory of Open Access Journals (Sweden)

    Antonino S. Aricò

    2015-11-01

    Full Text Available Sulfonic acid-functionalized polymer electrolyte membranes alternative to Nafion® were developed. These were hydrocarbon systems, such as blend sulfonated polyetheretherketone (s-PEEK, new generation perfluorosulfonic acid (PFSA systems, and composite zirconium phosphate–PFSA polymers. The membranes varied in terms of composition, equivalent weight, thickness, and filler and were investigated with regard to their methanol permeation characteristics and proton conductivity for application in direct methanol fuel cells. The behavior of the membrane electrode assemblies (MEA was investigated in fuel cell with the aim to individuate a correlation between membrane characteristics and their performance in a direct methanol fuel cell (DMFC. The power density of the DMFC at 60 °C increased according to a square root-like function of the membrane selectivity. This was defined as the reciprocal of the product between area specific resistance and crossover. The power density achieved at 60 °C for the most promising s-PEEK-based membrane-electrode assembly (MEA was higher than the benchmark Nafion® 115-based MEA (77 mW·cm−2 vs. 64 mW·cm−2. This result was due to a lower methanol crossover (47 mA·cm−2 equivalent current density for s-PEEK vs. 120 mA·cm−2 for Nafion® 115 at 60 °C as recorded at OCV with 2 M methanol and a suitable area specific resistance (0.15 Ohm cm2 for s-PEEK vs. 0.22 Ohm cm2 for Nafion® 115.

  4. Enhanced methanol utilization in direct methanol fuel cell

    Science.gov (United States)

    Ren, Xiaoming; Gottesfeld, Shimshon

    2001-10-02

    The fuel utilization of a direct methanol fuel cell is enhanced for improved cell efficiency. Distribution plates at the anode and cathode of the fuel cell are configured to distribute reactants vertically and laterally uniformly over a catalyzed membrane surface of the fuel cell. A conductive sheet between the anode distribution plate and the anodic membrane surface forms a mass transport barrier to the methanol fuel that is large relative to a mass transport barrier for a gaseous hydrogen fuel cell. In a preferred embodiment, the distribution plate is a perforated corrugated sheet. The mass transport barrier may be conveniently increased by increasing the thickness of an anode conductive sheet adjacent the membrane surface of the fuel cell.

  5. Sterion membranes in Direct Methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Linares, J. J.; Lobato, J.; Canizares, P.; Rodrigo, M. A.; Fernandez, A.

    2005-07-01

    Direct Methanol Fuel Cells (DMFCs) has been postulated as an alternative to traditional hydrogen fed Polymer Electrolyte Membrane Fuel Cells (H2-PEMFCs). Among their advantages, it can be pointed out the low cost of the fuel, simplicity of design, large availability, easy handling and distribution. However, there are still some challenges in this field, such as the development of electrocatalysts which can enhance the electrokinetics of methanol oxidation, the discovery of an electrolyte membrane with high conductivity and low methanol crossover at the same time and the production of methanol-tolerant electrocatalysts with high activity for oxygen reduction. So far, Nafion 117 has been the polymer membrane most widely used in DMFCs. Yet, it is well known that Nafion (Du Pont Inc.) membranes are not good barrier for methanol, so that the coulombic efficiency of Nafion-based DMFCs is significantly reduced by the chemical oxidation of methanol in the cathode. Recently, a new perfluorinated polymer with sulphonic acid groups (PFSA) has been developed, under the commercial name of Sterion (David Fuel Cell Components). As a difference as opposed to Nafion, this membrane is cast by the solution casting method, which provides a different sulphonic cluster configuration as compared to the extrusion cast Nafion membranes, which may give rise to different methanol crossover behaviour. In this work, it has been studied and analysed the suitability of Sterion in the DMFCs field. For that, it has been measured the methanol permeability of this membrane at different solute concentration and temperature, and its performance in an actual fuel cell at different operational conditions, such as methanol concentration, temperature and back pressure. Tests have been made using both oxygen and air in the cathode and half-cell potentials have been evaluated in some measurements in order to discriminate the contribution of both semi-reactions to the overall cell overvoltage. A lifetime

  6. Silicon Based Direct Methanol Fuel Cells

    DEFF Research Database (Denmark)

    Larsen, Jackie Vincent

    The purpose of this project has been to investigate and fabricate small scale Micro Direct Methanol Fuel Cells (μDMFC). They are investigated as a possible alternative for Zinc-air batteries in small size consumer devices such as hearing aids. In such devices the conventional rechargeable batteries...... such as lithium-ion batteries have insufficiently low energy density. Methanol is a promising fuel for such devices due to the high energy density and ease of refueling compared to charging batteries, making μDMFC a suitable replacement energy source. In this Ph.D. dissertation, silicon micro fabrication...

  7. Selectivity of Direct Methanol Fuel Cell Membranes

    Science.gov (United States)

    Aricò, Antonino S.; Sebastian, David; Schuster, Michael; Bauer, Bernd; D’Urso, Claudia; Lufrano, Francesco; Baglio, Vincenzo

    2015-01-01

    Sulfonic acid-functionalized polymer electrolyte membranes alternative to Nafion® were developed. These were hydrocarbon systems, such as blend sulfonated polyetheretherketone (s-PEEK), new generation perfluorosulfonic acid (PFSA) systems, and composite zirconium phosphate–PFSA polymers. The membranes varied in terms of composition, equivalent weight, thickness, and filler and were investigated with regard to their methanol permeation characteristics and proton conductivity for application in direct methanol fuel cells. The behavior of the membrane electrode assemblies (MEA) was investigated in fuel cell with the aim to individuate a correlation between membrane characteristics and their performance in a direct methanol fuel cell (DMFC). The power density of the DMFC at 60 °C increased according to a square root-like function of the membrane selectivity. This was defined as the reciprocal of the product between area specific resistance and crossover. The power density achieved at 60 °C for the most promising s-PEEK-based membrane-electrode assembly (MEA) was higher than the benchmark Nafion® 115-based MEA (77 mW·cm−2 vs. 64 mW·cm−2). This result was due to a lower methanol crossover (47 mA·cm−2 equivalent current density for s-PEEK vs. 120 mA·cm−2 for Nafion® 115 at 60 °C as recorded at OCV with 2 M methanol) and a suitable area specific resistance (0.15 Ohm cm2 for s-PEEK vs. 0.22 Ohm cm2 for Nafion® 115). PMID:26610582

  8. Development of new membrane materials for direct methanol fuel cells

    NARCIS (Netherlands)

    Yildirim, Mustafa Hakan

    2009-01-01

    Development of new membrane materials for direct methanol fuel cells Direct methanol fuel cells (DMFCs) can convert the chemical energy of a fuel directly into electrical energy with high efficiency and low emission of pollutants. DMFCs can be used as the power sources to portable electronic devices

  9. Development of new membrane materials for direct methanol fuel cells

    NARCIS (Netherlands)

    Yildirim, M.H.

    2009-01-01

    Development of new membrane materials for direct methanol fuel cells Direct methanol fuel cells (DMFCs) can convert the chemical energy of a fuel directly into electrical energy with high efficiency and low emission of pollutants. DMFCs can be used as the power sources to portable electronic devices

  10. Methanol-Tolerant Cathode Catalyst Composite For Direct Methanol Fuel Cells

    Science.gov (United States)

    Zhu, Yimin; Zelenay, Piotr

    2006-03-21

    A direct methanol fuel cell (DMFC) having a methanol fuel supply, oxidant supply, and its membrane electrode assembly (MEA) formed of an anode electrode and a cathode electrode with a membrane therebetween, a methanol oxidation catalyst adjacent the anode electrode and the membrane, an oxidant reduction catalyst adjacent the cathode electrode and the membrane, comprises an oxidant reduction catalyst layer of a platinum-chromium alloy so that oxidation at the cathode of methanol that crosses from the anode through the membrane to the cathode is reduced with a concomitant increase of net electrical potential at the cathode electrode.

  11. The Catalysis of NAD+ on Methanol Anode Oxidation Electrode for Direct Methanol Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ping; PAN Mu; YUAN Run-zhang

    2004-01-01

    A tentative idea of developing a liquid-catalytic system on methanol anode oxidation was proposed by analyzing the characteristics of methanol anode oxidation in direct methanol fuel cell. The kinetics of methanol oxidation at a glassy carbon electrode in the presence of nicotinamide adenine dinucleotide (NAD+) was investigated. It is found that the current density of methanol oxidation increases greatly and the electrochemical reaction impedance reduces obviously in the presence of NAD+ compared with those in the absence of NAD+. The catalytic activity of NAD+ is sensitive to temperature. When the temperature preponderates over 45℃, NAD+ is out of function of catalysis for methanol oxidation, which is probably due to the denaturation of NAD+ at a relatively high temperature.

  12. A Nafion-Ceria Composite Membrane Electrolyte for Reduced Methanol Crossover in Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    Parthiban Velayutham

    2017-02-01

    Full Text Available An alternative Nafion composite membrane was prepared by incorporating various loadings of CeO2 nanoparticles into the Nafion matrix and evaluated its potential application in direct methanol fuel cells (DMFCs. The effects of CeO2 in the Nafion matrix were systematically studied in terms of surface morphology, thermal and mechanical stability, proton conductivity and methanol permeability. The composite membrane with optimum filler content (1 wt. % CeO2 exhibits a proton conductivity of 176 mS·cm−1 at 70 °C, which is about 30% higher than that of the unmodified membrane. Moreover, all the composite membranes possess a much lower methanol crossover compared to pristine Nafion membrane. In a single cell DMFC test, MEA fabricated with the optimized composite membrane delivered a peak power density of 120 mW·cm−2 at 70 °C, which is about two times higher in comparison with the pristine Nafion membrane under identical operating conditions.

  13. Long Term Performance Study of a Direct Methanol Fuel Cell Fed with Alcohol Blends

    Directory of Open Access Journals (Sweden)

    Eleuterio Mora

    2013-01-01

    Full Text Available The use of alcohol blends in direct alcohol fuel cells may be a more environmentally friendly and less toxic alternative to the use of methanol alone in direct methanol fuel cells. This paper assesses the behaviour of a direct methanol fuel cell fed with aqueous methanol, aqueous ethanol and aqueous methanol/ethanol blends in a long term experimental study followed by modelling of polarization curves. Fuel cell performance is seen to decrease as the ethanol content rises, and subsequent operation with aqueous methanol only partly reverts this loss of performance. It seems that the difference in the oxidation rate of these alcohols may not be the only factor affecting fuel cell performance.

  14. Macroscopic Modeling of Transport Phenomena in Direct Methanol Fuel Cells

    DEFF Research Database (Denmark)

    Olesen, Anders Christian

    An increasing need for energy efficiency and high energy density has sparked a growing interest in direct methanol fuel cells for portable power applications. This type of fuel cell directly generates electricity from a fuel mixture consisting of methanol and water. Although this technology...... for studying their transport. In this PhD dissertation the macroscopic transport phenomena governing direct methanol fuel cell operation are analyzed, discussed and modeled using the two-fluid approach in the computational fluid dynamics framework of CFX 14. The overall objective of this work is to extend...... the present fundamental understanding of direct methanol fuel cell operation by developing a three-dimensional, two-phase, multi-component, non-isotherm mathematical model including detailed non-ideal thermodynamics, non-equilibrium phase change and non-equilibrium sorption-desorption of methanol and water...

  15. Thermodynamic properties of direct methanol polymer electrolyte fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Ji Yun; Bae, Young Chan [Division of Chemical Engineering and Molecular Thermodynamics Laboratory, Hanyang University, Sungdonggu Haengdangdong 17, Seoul 133-791 (Korea, Republic of); Sun, Yang Kook [Division of Chemical Engineering and Center for Information and Communication, Materials, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2005-08-18

    A new semi-empirical model is established to describe the cell voltage of a direct methanol fuel cell (DMFC) as a function of current density. The model equation is validated experimental data over a wide range of a methanol concentration and temperatures. A number of existing models are semi-empirical. They, however, have a serious mathematical defect. When the current density, j, becomes zero, the equation should reduce to the open circuit voltage, E{sub 0}. These models, however, do not meet the mathematical boundary condition. The proposed model focuses on very unfavorable conditions for the cell operation, i.e. low methanol solution concentrations and relatively low cell temperatures. A newly developed semi-empirical equation with reasonable boundary conditions includes the methanol crossover effect that plays a major role in determining the cell voltage of DMFC. Also, it contains methanol activity based on thermodynamic functions to represent methanol crossover effect. (author)

  16. Novel Anode Catalyst for Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    S. Basri

    2014-01-01

    Full Text Available PtRu catalyst is a promising anodic catalyst for direct methanol fuel cells (DMFCs but the slow reaction kinetics reduce the performance of DMFCs. Therefore, this study attempts to improve the performance of PtRu catalysts by adding nickel (Ni and iron (Fe. Multiwalled carbon nanotubes (MWCNTs are used to increase the active area of the catalyst and to improve the catalyst performance. Electrochemical analysis techniques, such as energy dispersive X-ray spectrometry (EDX, X-ray diffraction (XRD, field emission scanning electron microscopy (FESEM, and X-ray photoelectron spectroscopy (XPS, are used to characterize the kinetic parameters of the hybrid catalyst. Cyclic voltammetry (CV is used to investigate the effects of adding Fe and Ni to the catalyst on the reaction kinetics. Additionally, chronoamperometry (CA tests were conducted to study the long-term performance of the catalyst for catalyzing the methanol oxidation reaction (MOR. The binding energies of the reactants and products are compared to determine the kinetics and potential surface energy for methanol oxidation. The FESEM analysis results indicate that well-dispersed nanoscale (2–5 nm PtRu particles are formed on the MWCNTs. Finally, PtRuFeNi/MWCNT improves the reaction kinetics of anode catalysts for DMFCs and obtains a mass current of 31 A g−1 catalyst.

  17. Recent Progress in Direct Partial Oxidation of Methane to Methanol

    Institute of Scientific and Technical Information of China (English)

    Qijian Zhang; Dehua He; Qiming Zhu

    2003-01-01

    The direct conversion of methane to methanol has attracted a great deal of attention for nearly a century since it was first found possible in 1902, and it is still a challenging task. This review article describes recent advancements in the direct partial oxidation of methane to methanol. The history of direct oxidation of methane and the difficulties encountered in the partial oxidation of methane to methanol are briefly summarized. Recently reported developments in gas-phase homogeneous oxidation, heterogeneous catalytic oxidation and liquid phase homogeneous catalytic oxidation of methane are reviewed.

  18. Effect of Methanol Crossover in a Liquid-FeedPolymer-Electrolyte Direct Methanol Fuel Cell

    OpenAIRE

    Ravikumar, MK; Shukla, AK

    1996-01-01

    The performance of a liquid-feed direct methanol fuel cell employing a proton-exchange membrane electrolyte with Pt-Ru/C as anode and Pt/C as cathode is reported. The fuel cell can deliver a power density of ca. 0.2 $W/cm^2$ at 95°C, sufficient to suggest that the stack construction is well worthwhile.Methanol crossover across the polymer electrolyte at concentrations beyond 2 M methanol affects the performance of the cell which appreciates with increasing operating temperature.

  19. Direct methanol feed fuel cell and system

    Science.gov (United States)

    Surampudi, Subbarao (Inventor); Frank, Harvey A. (Inventor); Narayanan, Sekharipuram R. (Inventor); Chun, William (Inventor); Jeffries-Nakamura, Barbara (Inventor); Kindler, Andrew (Inventor); Halpert, Gerald (Inventor)

    2009-01-01

    Improvements to non acid methanol fuel cells include new formulations for materials. The platinum and ruthenium are more exactly mixed together. Different materials are substituted for these materials. The backing material for the fuel cell electrode is specially treated to improve its characteristics. A special sputtered electrode is formed which is extremely porous. The fuel cell system also comprises a fuel supplying part including a meter which meters an amount of fuel which is used by the fuel cell, and controls the supply of fuel based on said metering.

  20. Modelling and experimental studies on a direct methanol fuel cell working under low methanol crossover and high methanol concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, V.B.; Pinto, A.M.F.R. [Centro de Estudos de Fenomenos de Transporte, Departamento de Eng. Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Rangel, C.M. [Instituto Nacional de Energia e Geologia, Fuel Cells and Hydrogen, Estrada do Paco do Lumiar, 1649-038 Lisboa (Portugal)

    2009-08-15

    A number of issues need to be resolved before DMFC can be commercially viable such as the methanol crossover and water crossover which must be minimised in portable DMFCs. The main gain of this work is to systematically vary commercial MEA materials and check their influence on the cell performance of a direct methanol fuel cell operating at close to room temperature. A detailed experimental study on the performance of an <> developed DMFC with 25 cm{sup 2} of active membrane area, working near the ambient conditions is described. Tailored MEAs (membrane-electrode assemblies), with different structures and combinations of gas diffusion layers (GDLs), were designed and tested in order to select optimal working conditions at high methanol concentration levels without sacrificing performance. The experimental polarization and power density curves were successfully compared with the predictions of a steady state, one-dimensional model accounting for coupled heat and mass transfer, along with the electrochemical reactions occurring in the DMFC recently developed by the same authors. The influence of the anode gas diffusion layer media, the membrane thickness and the MEA properties on the cell performance are explained under the light of the predicted methanol crossover rate across the membrane. A tailored MEA build-up with the common available commercial materials was proposed to achieve relatively low methanol crossover, operating at high methanol concentrations. The use of adequate materials for the gas diffusion layers (carbon paper at the anode GDL and carbon cloth at the cathode GDL) enables the use of thinner membranes enhancing the water back diffusion which is essential to work at high methanol concentrations. (author)

  1. Novel Materials for High Efficiency Direct Methanol Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Carson, Stephen; Mountz, David; He, Wensheng; Zhang, Tao

    2013-12-31

    Direct methanol fuel cell membranes were developed using blends of different polyelectrolytes with PVDF. The membranes showed complex relationships between polyelectrolyte chemistry, morphology, and processing. Although the PVDF grade was found to have little effect on the membrane permselectivity, it does impact membrane conductivity and methanol permeation values. Other factors, such as varying the polyelectrolyte polarity, using varying crosslinking agents, and adjusting the equivalent weight of the membranes impacted methanol permeation, permselectivity, and areal resistance. We now understand, within the scope of the project work completed, how these inter-related performance properties can be tailored to achieve a balance of performance.

  2. Studies on an ultrasonic atomization feed direct methanol fuel cell.

    Science.gov (United States)

    Wu, Chaoqun; Liu, Linghao; Tang, Kai; Chen, Tao

    2017-01-01

    Direct methanol fuel cell (DMFC) is promising as an energy conversion device for the replacement of conventional chemical cell in future, owing to its convenient fuel storage, high energy density and low working temperature. The development of DMFC technology is currently limited by catalyst poison and methanol crossover. To alleviate the methanol crossover, a novel fuel supply system based on ultrasonic atomization is proposed. Experimental investigations on this fuel supply system to evaluate methanol permeation rates, open circuit voltages (OCVs) and polarization curves under a series of conditions have been carried out and reported in this paper. In comparison with the traditional liquid feed DMFC system, it can be found that the methanol crossover under the ultrasonic atomization feed system was significantly reduced because the DMFC reaches a large stable OCV value. Moreover, the polarization performance does not vary significantly with the liquid feed style. Therefore, the cell fed by ultrasonic atomization can be operated with a high concentration methanol to improve the energy density of DMFC. Under the supply condition of relatively high concentration methanol such as 4M and 8M, the maximum power density fed by ultrasonic atomization is higher than liquid by 6.05% and 12.94% respectively.

  3. Improved Flow-Field Structures for Direct Methanol Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Gurau, Bogdan

    2013-05-31

    The direct methanol fuel cell (DMFC) is ideal if high energy-density liquid fuels are required. Liquid fuels have advantages over compressed hydrogen including higher energy density and ease of handling. Although state-of-the-art DMFCs exhibit manageable degradation rates, excessive fuel crossover diminishes system energy and power density. Although use of dilute methanol mitigates crossover, the concomitant lowering of the gross fuel energy density (GFED) demands a complex balance-of-plant (BOP) that includes higher flow rates, external exhaust recirculation, etc. An alternative approach is redesign of the fuel delivery system to accommodate concentrated methanol. NuVant Systems Inc. (NuVant) will maximize the GFED by design and assembly of a DMFC that uses near neat methanol. The approach is to tune the diffusion of highly concentrated methanol (to the anode catalytic layer) to the back-diffusion of water formed at the cathode (i.e. in situ generation of dilute methanol at the anode layer). Crossover will be minimized without compromising the GFED by innovative integration of the anode flow-field and the diffusion layer. The integrated flow-field-diffusion-layers (IFDLs) will widen the current and potential DMFC operating ranges and enable the use of cathodes optimized for hydrogen-air fuel cells.

  4. DIRECT METHANOL FUEL CELLS AT REDUCED CATALYST LOADINGS

    Energy Technology Data Exchange (ETDEWEB)

    P. ZELENAY; F. GUYON; SM. GOTTESFELD

    2001-05-01

    We focus in this paper on the reduction of catalyst loading in direct methanol fuel cells currently under development at Los Alamos National Laboratory. Based on single-cell DMFC testing, we discuss performance vs. catalyst loading trade-offs and demonstrate optimization of the anode performance. We also show test data for a short five-cell DMFC stack with the average total platinum loading of 0.53 mg cm{sup {minus}2} and compare performance of this stack with the performance of a single direct methanol fuel cell using similar total amount of precious metal.

  5. Direct methanol fuel cells at reduced catalyst loadings

    Energy Technology Data Exchange (ETDEWEB)

    Zelenay, P. (Piotr); Guyon, F. (Francois); Gottesfeld, Shimshon

    2001-01-01

    We focus in this paper on the reduction of catalyst loading in direct methanol fuel cells currently under development at Los Alamos National Laboratory. Based on single-cell DMFC testing, we discuss performance vs. catalyst loading trade-offs and demonstrate optimization of the anode performance. We also show test data for a short five-cell DMFC stack with the average total platinum loading of 0.53 mg cm{sup -2} and compare performance of this stack with the performance of a single direct methanol fuel cell using similar total amount of precious metal.

  6. The Pore Structure of Direct Methanol Fuel Cell Electrodes

    DEFF Research Database (Denmark)

    Lund, Peter Brilner

    2005-01-01

    The pore structure and morphology of direct methanol fuel cell electrodes are characterized using mercury intrusion porosimetry and scanning electron microscopy. It is found that the pore size distributions of printed primer and catalyst layers are largely dictated by the powders used to make the...

  7. Reactivity descriptors for direct methanol fuel cell anode catalysts

    DEFF Research Database (Denmark)

    Ferrin, Peter; Nilekar, Anand Udaykumar; Greeley, Jeff

    2008-01-01

    We have investigated the anode reaction in direct methanol fuel cells using a database of adsorption free energies for 16 intermediates on 12 close-packed transition metal surfaces calculated with periodic, self-consistent, density functional theory (DFT-GGA). This database, combined with a simple...

  8. On direct and indirect methanol fuel cells for transportation applications

    Energy Technology Data Exchange (ETDEWEB)

    Gottesfield, S.

    1996-04-01

    Research on direct oxidation methanol fuel cells (DMFCs) and polymer electrolyte fuel cells (PEFCs) is discussed. Systems considered for transportation applications are addressed. The use of platinum/ruthenium anode electrocatalysts and platinum cathode electrocatalysts in polymer electrolyte DMFCs has resulted in significant performance enhancements.

  9. Studies on Methanol Crossover in Liquid-Feed Direct Methanol Pem Fuel Cells

    Science.gov (United States)

    Narayanan, S. R.

    1995-01-01

    The performance of liquid feed direct methanol fuel cells using various types of Nafion membranes as the solid polymer electrolyte have been studied. The rate of fuel crossover and electrical performance has been measured for cells with Nafion membranes of various thicknesses and equivalent weights. The crossover rate is found to decrease with increasing thickness and applied current. The dependence of crossover rate on current density can be understood in terms of a simple linear diffusion model which suggests that the crossover rate can be influenced by the electrode structure in addition to the membrane. The studies suggest that Nafion EW 1500 is a very promising alternate to Nafion EW 1100 for direct methanol fuel cells.

  10. Response of a direct methanol fuel cell to fuel change

    Energy Technology Data Exchange (ETDEWEB)

    Leo, T.J. [Dpto de Sistemas Oceanicos y Navales- ETSI Navales, Univ. Politecnica de Madrid, Avda Arco de la Victoria s/n, 28040 Madrid (Spain); Raso, M.A.; de la Blanca, E. Sanchez [Dpto de Quimica Fisica I- Fac. CC. Quimicas, Univ. Complutense de Madrid, Avda Complutense s/n, 28040 Madrid (Spain); Navarro, E.; Villanueva, M. [Dpto de Motopropulsion y Termofluidodinamica, ETSI Aeronauticos, Univ. Politecnica de Madrid, Pza Cardenal Cisneros 3, 28040 Madrid (Spain); Moreno, B. [Instituto de Ceramica y Vidrio, Consejo Superior de Investigaciones Cientificas, C/Kelsen 5, Campus de la UAM, 28049 Cantoblanco, Madrid (Spain)

    2010-10-15

    Methanol and ethanol have recently received much attention as liquid fuels particularly as alternative 'energy-vectors' for the future. In this sense, to find a direct alcohol fuel cell that able to interchange the fuel without losing performances in an appreciable way would represent an evident advantage in the field of portable applications. In this work, the response of a in-house direct methanol fuel cell (DMFC) to the change of fuel from methanol to ethanol and its behaviour at different ambient temperature values have been investigated. A corrosion study on materials suitable to fabricate the bipolar plates has been carried out and either 316- or 2205-duplex stainless steels have proved to be adequate for using in direct alcohol fuel cells. Polarization curves have been measured at different ambient temperature values, controlled by an experimental setup devised for this purpose. Data have been fitted to a model taking into account the temperature effect. For both fuels, methanol and ethanol, a linear dependence of adjustable parameters with temperature is obtained. Fuel cell performance comparison in terms of open circuit voltage, kinetic and resistance is established. (author)

  11. Ruthenium–Platinum Catalysts and Direct Methanol Fuel Cells (DMFC: A Review of Theoretical and Experimental Breakthroughs

    Directory of Open Access Journals (Sweden)

    Ana S. Moura

    2017-02-01

    Full Text Available The increasing miniaturization of devices creates the need for adequate power sources and direct methanol fuel cells (DMFC are a strong option in the various possibilities under current development. DMFC catalysts are mostly based on platinum, for its outperformance in three key areas (activity, selectivity and stability within methanol oxidation framework. However, platinum poisoning with products of methanol oxidation led to the use of alloys. Ruthenium–platinum alloys are preferred catalysts active phases for methanol oxidation from an industrial point of view and, indeed, ruthenium itself is a viable catalyst for this reaction. In addition, the route of methanol decomposition is crucial in the goal of producing H2 from water reaction with methanol. However, the reaction pathway remains elusive and new approaches, namely in computational methods, have been ensued to determine it. This article reviews the various recent theoretical approaches for determining the pathway of methanol decomposition, and systematizes their validation with experimental data, within methodological context.

  12. Mixtures of methanol and 2-propanol as a potential fuel for direct alcohol fuel cells

    Directory of Open Access Journals (Sweden)

    S. LJ. GOJKOVIC

    2007-12-01

    Full Text Available The electrochemical oxidation of methanol, 2-propanol, and their mixtures was investigated on a Pt/C thin film electrode in acid solution. It was confirmed that the oxidation of 2-propanol commences at less positive potentials than that of methanol and exhibits significantly higher oxidation current densities at low potentials. When both methanol and 2-propanol were present in the solution, the onset of the oxidation current was the same as for the oxidation of pure 2-propanol. Although both alcohols inhibit the oxidation reaction of each other to a certain extent, steady-state polarization measurements showed that their mixture provides higher current densities than single alcohols over the entire potential region from the hydrogen region to oxide formation on the Pt surface. This implies that the addition of 2-propanol into the fuel may extend the operational range of direct methanol fuel cells.

  13. Passive direct methanol fuel cells in silicon technology

    Energy Technology Data Exchange (ETDEWEB)

    Sabate, N.; Esquivel, J.P.; Santander, J.; Torres, N.; Gracia, I.; Ivanov, P.; Fonseca, L.; Figueras, E.; Cane, C. [Inst. de Microelectronica de Barcelona-CNM (CSIC), Barcelona (Spain)

    2008-04-15

    The increased demand for light and efficient power sources in the past decade can be attributed to the increasing presence of sensing and actuating microelectromechanical systems (MEMS) used different application fields such as the automotive and food industry. The integration of these power sources presents an opportunity for the future advancement of MEMS based devices. Much research has been conducted in the field of active methanol fuel cells, in which the liquid fuel and the oxidant are generally pumped externally. However, the application of these types of cells as portable power sources has led to simpler approaches that give up ancillary devices such as pumps or gas compressors and the parasitic power losses associated with them. This passive fuel cell approach offers the advantage of a simpler and compact design. This article presented the main features of a passive silicon direct methanol fuel cell. The microdevice was based on a hybrid approach composed of a commercial membrane electrode assembly (MEA). It was concluded that methanol concentration has little impact on the fuel cell's maximum power density, and is comparable to values reported in the literature for larger passive and stainless-steel fuel cells. Temperature measurements revealed that the fuel cell temperature did not change significantly and is independent of the methanol crossover rate. 12 refs., 1 tab., 5 figs.

  14. Selective anaerobic oxidation of methane enables direct synthesis of methanol.

    Science.gov (United States)

    Sushkevich, Vitaly L; Palagin, Dennis; Ranocchiari, Marco; van Bokhoven, Jeroen A

    2017-05-05

    Direct functionalization of methane in natural gas remains a key challenge. We present a direct stepwise method for converting methane into methanol with high selectivity (~97%) over a copper-containing zeolite, based on partial oxidation with water. The activation in helium at 673 kelvin (K), followed by consecutive catalyst exposures to 7 bars of methane and then water at 473 K, consistently produced 0.204 mole of CH3OH per mole of copper in zeolite. Isotopic labeling confirmed water as the source of oxygen to regenerate the zeolite active centers and renders methanol desorption energetically favorable. On the basis of in situ x-ray absorption spectroscopy, infrared spectroscopy, and density functional theory calculations, we propose a mechanism involving methane oxidation at Cu(II) oxide active centers, followed by Cu(I) reoxidation by water with concurrent formation of hydrogen. Copyright © 2017, American Association for the Advancement of Science.

  15. Methanol Tolerant PWA-Pt/C Catalyst with Excellent Electrocatalytic Activity for Oxygen Reduction in Direct Methanol Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    It was reported for the first time that phosphorictungstenic acid (PWA) could promote the oxygen reduction reaction (ORR) and inhibit the methanol oxidation reaction at the cathodic Pt/C catalyst in the direct methanol fuel cell (DMFC). When the weight ratio of PWA to Pt/C is 1,the composite catalyst increases the reduction current of oxygen by about 38% and decreases the oxidation current of methanol by about 76% compared with that of the Pt/C catalyst.

  16. Direct methanol feed fuel cell with reduced catalyst loading

    Science.gov (United States)

    Kindler, Andrew (Inventor)

    1999-01-01

    Improvements to direct feed methanol fuel cells include new protocols for component formation. Catalyst-water repellent material is applied in formation of electrodes and sintered before application of ionomer. A membrane used in formation of an electrode assembly is specially pre-treated to improve bonding between catalyst and membrane. The improved electrode and the pre-treated membrane are assembled into a membrane electrode assembly.

  17. Direct methanol-air fuel cells for road transportation

    Energy Technology Data Exchange (ETDEWEB)

    McNicol, B.D. [The Beeches, Kelsall (United Kingdom); Rand, D.A.J. [Commonwealth Scientific and Industrial Research Organization, Clayton, VIC (Australia); Williams, K.R. [Cambridge Univ. (United Kingdom). Dept. of Metallurgy and Materials Science

    1999-10-01

    The direct methanol-air fuel cell is reviewed with special attention to its use in road transportation applications. The history of the technology is discussed and the various problems associated with its commercial development are assessed, in particular the mechanisms of the electrode reactions, the development of effective catalysts, and the possible electrolytes which can be used. The barriers to successful commercialization are reviewed and suggestions for future work are given. (orig.)

  18. Development and Fielding of a Direct Methanol Fuel Cell

    Science.gov (United States)

    2010-03-01

    fuel cell to power operational test instrumentation in support of the future combat systems test and evaluation. This unit also has application by the German Bundeswehr as a battery-charging station and auxiliary power unit. The direct methanol fuel cell is characterized by its low noise emission, minimal thermal signature, and high fuel efficiency that will enable continuously sustained operation for long duration missions in the

  19. Electrocatalytic performance of Pt/Ru/Sn/W fullerene electrode for methanol oxidation in direct methanol fuel cell

    Institute of Scientific and Technical Information of China (English)

    Mohammad Karimi; Forouzan Aboufazeli; Hamid Reza Lotfi Zadeh Zhad; Omid Sadeghi; Ezzatollah Najafi

    2013-01-01

    In this work,fullerene was modified by platinum,ruthenium,tin and tungsten nanoparticles.The material was characterized by XRD,ICP-OES and TEM micrograph.The average nanoparticle size on fullerene was 5 ~ 8 nm.The application of this material was investigated as a catalyst for methanol oxidation in direct methanol fuel cell.A glassy carbon electrode was modified by Pt/Ru/Sn/W fullerene and electrocatalytic activity of the electrode toward methanol oxidation in basic medium has been demonstrated and investigated using cyclic voltammetry.The catalyst showed good reactivity for methanol oxidation.

  20. BARRIERS TO COMMERCIALIZATION OF PASSIVE DIRECT METHANOL FUEL CELLS: A REVEIW

    Directory of Open Access Journals (Sweden)

    N. K. SHRIVASTAVA

    2011-07-01

    Full Text Available Fuel cells are electro-chemical reactors which realize the direct conversion of the chemical energy of reactants to electrical energy, with high efficiency and high environmental compatibility. This article is concerned with one of the most advance fuel cells- direct methanol fuel cells (DMFCs. We present a comprehensive review on the commercialization barriers of passive DMFCs. The paper also summarizes past research efforts and possible future directions towards these problems.

  1. High specific power, direct methanol fuel cell stack

    Science.gov (United States)

    Ramsey, John C.; Wilson, Mahlon S.

    2007-05-08

    The present invention is a fuel cell stack including at least one direct methanol fuel cell. A cathode manifold is used to convey ambient air to each fuel cell, and an anode manifold is used to convey liquid methanol fuel to each fuel cell. Tie-bolt penetrations and tie-bolts are spaced evenly around the perimeter to hold the fuel cell stack together. Each fuel cell uses two graphite-based plates. One plate includes a cathode active area that is defined by serpentine channels connecting the inlet manifold with an integral flow restrictor to the outlet manifold. The other plate includes an anode active area defined by serpentine channels connecting the inlet and outlet of the anode manifold. Located between the two plates is the fuel cell active region.

  2. Measurement and estimation of species distribution in a direct methanol fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Celik, Selahattin; Mat, Mahmut D. [Nigde University, Mechanical Engineering Department, 51100 Nigde (Turkey)

    2010-03-15

    Determination of methanol concentration in a direct methanol fuel cell is crucial for design improvement and performance enhancement. Methanol and water concentrations in a direct methanol fuel cell are experimentally and numerically investigated. In the experimental program, a single cell direct methanol fuel cell is developed and an experimental setup is devised to measure methanol and water concentrations and performance of the cell depending on operating conditions. In theoretical program a mathematical model which includes fluid flow, species distribution, electric field and electrochemistry is adapted and numerically solved. The results showed that the performance of a Direct Methanol Fuel Cell (DMFC) is mainly influenced by operating temperature. A large drop in methanol concentration methanol is measured at the inlet section of cell. The mathematical model is found to satisfactorily capture main physics involved in a DMFC. (author)

  3. Ultrasonic radiation to enable improvement of direct methanol fuel cell.

    Science.gov (United States)

    Wu, Chaoqun; Wu, Jiang; Luo, Hao; Wang, Sanwu; Chen, Tao

    2016-03-01

    To improve DMFC (direct methanol fuel cell) performance, a new method using ultrasonic radiation is proposed and a novel DMFC structure is designed and fabricated in the present paper. Three ultrasonic transducers (piezoelectric transducer, PZT) are integrated in the flow field plate to form the ultrasonic field in the liquid fuel. Ultrasonic frequency, acoustic power, and methanol concentration have been considered as variables in the experiments. With the help of ultrasonic radiation, the maximum output power and limiting current of cell can be independently increased by 30.73% and 40.54%, respectively. The best performance of DMFC is obtained at the condition of ultrasonic radiation (30 kHz and 4 W) fed with 2M methanol solution, because both its limiting current and output power reach their maximum value simultaneously (222 mA and 33.6 mW, respectively) under this condition. These results conclude that ultrasonic can be an alternative choice for improving the cell performance, and can facilitate a guideline for the optimization of DMFC. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Bifunctional activation of a direct methanol fuel cell

    Science.gov (United States)

    Kulikovsky, A. A.; Schmitz, H.; Wippermann, K.; Mergel, J.; Fricke, B.; Sanders, T.; Sauer, D. U.

    We report a novel method for performance recovery of direct methanol fuel cells. Lowering of air flow rate below a critical value turns the cell into bifunctional regime, when the oxygen-rich part of the cell generates current while the rest part works in electrolysis mode (electrolytic domain). Upon restoring the normal (super-critical) air flow rate, the galvanic performance of the electrolytic domain increases. This recovery effect is presumably attributed to Pt surface cleaning on the cathode with the simultaneous increase in catalyst utilization on the anode.

  5. Methanol-Tolerant Platinum-Palladium Catalyst Supported on Nitrogen-Doped Carbon Nanofiber for High Concentration Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    Jiyoung Kim

    2016-08-01

    Full Text Available Pt-Pd catalyst supported on nitrogen-doped carbon nanofiber (N-CNF was prepared and evaluated as a cathode electrode of the direct methanol fuel cell (DMFC. The N-CNF, which was directly synthesized by the catalytic chemical vapor deposition from acetonitrile at 640 °C, was verified as having a change of electrochemical surface properties such as oxygen reduction reaction (ORR activities and the electrochemical double layer compared with common carbon black (CB. To attain the competitive oxygen reduction reaction activity with methanol tolerance, the Pt and Pd metals were supported on the CB or the N-CNF. The physical and electrochemical characteristics of the N-CNF–supported Pt-Pd catalyst were examined and compared with catalyst supported on the CB. In addition, DMFC single cells using these catalysts as the cathode electrode were applied to obtain I-V polarization curves and constant current operating performances with high-concentration methanol as the fuel. Pt-Pd catalysts had obvious ORR activity even in the presence of methanol. The higher power density was obtained at all the methanol concentrations when it applied to the membrane electrode assembly (MEA of the DMFC. When the N-CNF is used as the catalyst support material, a better performance with high-concentration methanol is expected.

  6. Improved fullerene nanofiber electrodes used in direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Q [Nano Craft Technologies Co., Ltd., Tsukuba (Japan); Zhang, Y [Nationals Institute of Advanced Industrial Science and Technology, Tsukuba (Japan); Miyazawa, K; Kato, R; Hotta, K; Wakahara, T [National Institute for Materials Science, Tsukuba (Japan)], E-mail: yi.zhang@aist.go.jp, E-mail: q.wang@aist.go.jp

    2009-04-01

    Platinum supported on fullerene nanofibers as possible electrodes for direct methanol fuel cells (DMFC) were studied. Fullerene nanofiber with 20 wt% Pt loading was mixed with 5 wt% Nafion solution. The mixture paste was coated on Nafion 117 membrane and sandwiched with silicon plates. To increase the surface reaction area of catalyst, nanoimprint was used to fabricate micro-patterns in the Nafion proton exchange membrane. Nanoimprint pattern consisted of dots of 500 nm-in-diameter, 140 nm-in-depth and 1 {mu}m-in-spacing. The nanoimprint of the treated proton exchange membrane (PEM) was carried out in a desktop thermal nanoimprint system (NI273, Nano Craft Tech. Corp., Japan) at the optimized conditions of 130 {sup 0}C and pressure of 3 MPa for 6 min. Then the Pt-coated PEM was sandwiched with micro-channelled silicon plates to form a micro-DMFC. With passively feeding of 1 M methanol solution and air at room temperature, the as-prepared cell had the open circuit voltage of 0.34 V and the maximum power density of 0.30 mW/cm{sup 2}. Compared with a fresh cell, the results shows that nanofibers used in nanoimprinted PEM have an improvement on the performance of micro fuel cells.

  7. Direct Methanol Fuel Cell Prototype Demonstration for Consumer Electronics Applications

    Energy Technology Data Exchange (ETDEWEB)

    Carlstrom, Charles, M., Jr.

    2009-07-07

    This report is the final technical report for DOE Program DE-FC36-04GO14301 titled “Direct Methanol Fuel Cell Prototype Demonstration for Consumer Electronics Applications”. Due to the public nature of this report some of the content reported in confidential reports and meetings to the DOE is not covered in detail in this report and some of the content has been normalized to not show actual values. There is a comparison of the projects accomplishments with the objectives, an overview of some of the key subsystem work, and a review of the three levels of prototypes demonstrated during the program. There is also a description of the eventual commercial product and market this work is leading towards. The work completed under this program has significantly increased the understanding of how Direct Methanol Fuel Cells (DMFC) can be deployed successfully to power consumer electronic devices. The prototype testing has demonstrated the benefits a direct methanol fuel cell system has over batteries typically used for powering consumer electronic devices. Three generations of prototypes have been developed and tested for performance, robustness and life. The technologies researched and utilized in the fuel cell stack and related subsystems for these prototypes are leveraged from advances in other industries such as the hydrogen fueled PEM fuel cell industry. The work under this program advanced the state of the art of direct methanol fuel cells. The system developed by MTI micro fuel cells aided by this program differs significantly from conventional DMFC designs and offers compelling advantages in the areas of performance, life, size, and simplicity. The program has progressed as planned resulting in the completion of the scope of work and available funding in December 2008. All 18 of the final P3 prototypes builds have been tested and the results showed significant improvements over P2 prototypes in build yield, initial performance, and durability. The systems have

  8. Recovery Act: Advanced Direct Methanol Fuel Cell for Mobile Computing

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, James H. [University of North Florida; Cox, Philip [University of North Florida; Harrington, William J [University of North Florida; Campbell, Joseph L [University of North Florida

    2013-09-03

    ABSTRACT Project Title: Recovery Act: Advanced Direct Methanol Fuel Cell for Mobile Computing PROJECT OBJECTIVE The objective of the project was to advance portable fuel cell system technology towards the commercial targets of power density, energy density and lifetime. These targets were laid out in the DOE’s R&D roadmap to develop an advanced direct methanol fuel cell power supply that meets commercial entry requirements. Such a power supply will enable mobile computers to operate non-stop, unplugged from the wall power outlet, by using the high energy density of methanol fuel contained in a replaceable fuel cartridge. Specifically this project focused on balance-of-plant component integration and miniaturization, as well as extensive component, subassembly and integrated system durability and validation testing. This design has resulted in a pre-production power supply design and a prototype that meet the rigorous demands of consumer electronic applications. PROJECT TASKS The proposed work plan was designed to meet the project objectives, which corresponded directly with the objectives outlined in the Funding Opportunity Announcement: To engineer the fuel cell balance-of-plant and packaging to meet the needs of consumer electronic systems, specifically at power levels required for mobile computing. UNF used existing balance-of-plant component technologies developed under its current US Army CERDEC project, as well as a previous DOE project completed by PolyFuel, to further refine them to both miniaturize and integrate their functionality to increase the system power density and energy density. Benefits of UNF’s novel passive water recycling MEA (membrane electrode assembly) and the simplified system architecture it enabled formed the foundation of the design approach. The package design was hardened to address orientation independence, shock, vibration, and environmental requirements. Fuel cartridge and fuel subsystems were improved to ensure effective fuel

  9. Recovery Act: Advanced Direct Methanol Fuel Cell for Mobile Computing

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, James H. [University of North Florida; Cox, Philip [University of North Florida; Harrington, William J [University of North Florida; Campbell, Joseph L [University of North Florida

    2013-09-03

    ABSTRACT Project Title: Recovery Act: Advanced Direct Methanol Fuel Cell for Mobile Computing PROJECT OBJECTIVE The objective of the project was to advance portable fuel cell system technology towards the commercial targets of power density, energy density and lifetime. These targets were laid out in the DOE’s R&D roadmap to develop an advanced direct methanol fuel cell power supply that meets commercial entry requirements. Such a power supply will enable mobile computers to operate non-stop, unplugged from the wall power outlet, by using the high energy density of methanol fuel contained in a replaceable fuel cartridge. Specifically this project focused on balance-of-plant component integration and miniaturization, as well as extensive component, subassembly and integrated system durability and validation testing. This design has resulted in a pre-production power supply design and a prototype that meet the rigorous demands of consumer electronic applications. PROJECT TASKS The proposed work plan was designed to meet the project objectives, which corresponded directly with the objectives outlined in the Funding Opportunity Announcement: To engineer the fuel cell balance-of-plant and packaging to meet the needs of consumer electronic systems, specifically at power levels required for mobile computing. UNF used existing balance-of-plant component technologies developed under its current US Army CERDEC project, as well as a previous DOE project completed by PolyFuel, to further refine them to both miniaturize and integrate their functionality to increase the system power density and energy density. Benefits of UNF’s novel passive water recycling MEA (membrane electrode assembly) and the simplified system architecture it enabled formed the foundation of the design approach. The package design was hardened to address orientation independence, shock, vibration, and environmental requirements. Fuel cartridge and fuel subsystems were improved to ensure effective fuel

  10. A Critical Assessment of the Direct Catalytic Oxidation of Methane to Methanol.

    Science.gov (United States)

    Ravi, Manoj; Ranocchiari, Marco; van Bokhoven, Jeroen A

    2017-06-23

    Despite the emerging number of disparate approaches for the direct selective partial oxidation of methane, none of them has translated into an industrial process. The oxidation of methane to methanol is a difficult yet intriguing and rewarding task as it has the potential to eliminate the prevalent natural gas flaring by providing novel routes to its valorisation. This review considers the synthesis of methanol and methanol derivatives from methane by homogeneous and heterogeneous pathways. In establishing the severe limitations related to the direct catalytic synthesis of methanol from methane, we highlight the vastly superior performance of systems, which produce methanol derivatives or incorporate specific measures such as the use of multi-component catalysts to stabilise methanol. We thereby identify methanol protection as being indispensable in homogeneous and heterogeneous catalysis with regard to future research on this topic. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Bifunctional anode catalysts for direct methanol fuel cells

    DEFF Research Database (Denmark)

    Rossmeisl, Jan; Ferrin, Peter; Tritsaris, Georgios

    2012-01-01

    Using the binding energy of OH* and CO* on close-packed surfaces as reactivity descriptors, we screen bulk and surface alloy catalysts for methanol electro-oxidation activity. Using these two descriptors, we illustrate that a good methanol electro-oxidation catalyst must have three key properties......: (1) the ability to activate methanol, (2) the ability to activate water, and (3) the ability to react off surface intermediates (such as CO* and OH*). Based on this analysis, an alloy catalyst made up of Cu and Pt should have a synergistic effect facilitating the activity towards methanol electro....... Adding Cu to a Pt(111) surface increases the methanol oxidation current by more than a factor of three, supporting our theoretical predictions for improved electrocatalysts....

  12. Nano-Engineered Catalysts for Direct Methanol Fuel Cells

    Science.gov (United States)

    Myung, Nosang; Narayanan, Sekharipuram; Wiberg, Dean

    2008-01-01

    Nano-engineered catalysts, and a method of fabricating them, have been developed in a continuing effort to improve the performances of direct methanol fuel cells as candidate power sources to supplant primary and secondary batteries in a variety of portable electronic products. In order to realize the potential for high energy densities (as much as 1.5 W h/g) of direct methanol fuel cells, it will be necessary to optimize the chemical compositions and geometric configurations of catalyst layers and electrode structures. High performance can be achieved when catalyst particles and electrode structures have the necessary small feature sizes (typically of the order of nanometers), large surface areas, optimal metal compositions, high porosity, and hydrophobicity. The present method involves electrodeposition of one or more catalytic metal(s) or a catalytic-metal/polytetrafluoroethylene nanocomposite on an alumina nanotemplate. The alumina nanotemplate is then dissolved, leaving the desired metal or metal/polytetrafluoroethylene-composite catalyst layer. Unlike some prior methods of making fine metal catalysts, this method does not involve processing at elevated temperature; all processing can be done at room temperature. In addition, this method involves fewer steps and is more amenable to scaling up for mass production. Alumina nanotemplates are porous alumina membranes that have been fabricated, variously, by anodizing either pure aluminum or aluminum that has been deposited on silicon by electronbeam evaporation. The diameters of the pores (7 to 300 nm), areal densities of pores (as much as 7 x 10(exp 10)sq cm), and lengths of pores (up to about 100 nm) can be tailored by selection of fabrication conditions. In a given case, the catalytic metal, catalytic metal alloy, or catalytic metal/ polytetrafluoroethylene composite is electrodeposited in the pores of the alumina nanotemplate. The dimensions of the pores, together with the electrodeposition conditions

  13. Manufacturing technologies for direct methanol fuel cells (DMFCs)

    Energy Technology Data Exchange (ETDEWEB)

    Gluesen, Andreas; Mueller, Martin; Kimiaie, Nicola; Konradi, Irene; Mergel, Juergen; Stolten, Detlef [Forschungszentrum Juelich (Germany). Inst. of Energy Research - IEF-3: Fuel Cells

    2010-07-01

    Fuel cell research is focussing on increasing power density and lifetime and reducing costs of the whole fuel cell system. In order to reach these aims, it is necessary to develop appropriately designed components outgoing from high quality materials, a suitable manufacturing process and a well balanced system. To make use of the advantages that can be obtained by developing production technology, we are mainly improving the coating and assembling techniques for polymer electrolyte fuel cells, especially Direct Methanol Fuel Cells (DMFCs). Coating is used for making fuel cell electrodes as well as highly conductive contacts. Assembling is used to join larger components like membrane electrode assemblies (MEAs) and bipolar units consisting of flow fields and the separator plate, as well as entire stacks. On the one hand a reproducible manufacturing process is required to study fine differences in fuel cell performance affected by new materials or new designs. On the other hand a change in each parameter of the manufacturing process itself can change product properties and therefore affect fuel cell performance. As a result, gas diffusion electrodes (GDEs) are now produced automatically in square-meter batches, the hot-pressing of MEAs is a fully automated process and by pre-assembling the number of parts that have to be assembled in a stack was reduced by a factor of 10. These achievements make DMFC manufacturing more reproducible and less error-prone. All these and further developments of manufacturing technology are necessary to make DMFCs ready for the market. (orig.)

  14. Nafion®/H-ZSM-5 composite membranes with superior performance for direct methanol fuel cells

    NARCIS (Netherlands)

    Yildirim, Mustafa Hakan; Curos, Anna Roca; Motuzas, Julius; Julbe, Anne; Stamatialis, Dimitrios; Wessling, Matthias

    2009-01-01

    Solution cast composite direct methanol fuel cell membranes (DEZ) based on DE2020 Nafion® dispersion and in-house prepared H-ZSM-5 zeolites with different Si/Al ratios were prepared and thoroughly characterized for direct methanol fuel cell (DMFC) applications. All composite membranes have indeed l

  15. Noble metal nanowires incorporated Nafion {sup registered} membranes for reduction of methanol crossover in direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Z.X.; Liao, S.J.; Zeng, J.H. [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Shi, J.Y. [School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275 (China)

    2010-09-15

    We electrodeposited noble metal (palladium, platinum) nanowires into the hydrophilic pores of Nafion membrane for mitigating the problem of methanol crossover in direct methanol fuel cells (DMFCs). The DMFC performance result shows that the composite membranes yield lower rate of methanol crossover and better cell performance than the pure Nafion {sup registered} membrane. At low current densities, the Pd nanowire incorporated Nafion membrane shows the best performance. In comparison, the highest performance is achieved at higher current densities with the Pt nanowire modified Nafion membrane. Based on the above findings, we suggest that for the Pd nanowire incorporated Nafion membrane, the mechanism for the suppression of the methanol crossover is mainly the blocking effect due to the 'narrowed' hydrophilic channels in Nafion membrane. For the Pt nanowire modified Nafion membrane, the mechanism includes both increasing the membrane tortuosity and so-called 'on-way consumption' of methanol on the Pt nanowires deposited into the Nafion membrane when the fuel cell is discharging. (author)

  16. Materials and Manufacturing Challenges of Direct Methanol Fuel Cells

    Science.gov (United States)

    2009-04-27

    Pt-Ru rather than Pt is used to oxidize methanol fuel in a DMFC. The addition of Ru oxidizes the carbon monoxide (CO) intermediate formed during the...addition of other hydrophilic elements such as tin (Sn) to Pt is also known to enhance the catalyt- ic activity for methanol oxidation. While replacement...Communications, Vol. 10, 2008, p. 740. [20] Sarkar, A., A. Vadivel Murugan, and A. Manthiram, “ Synthesis and Characterization of Nanostructured Pd-Mo

  17. Increasing Fuel Efficiency of Direct Methanol Fuel Cell Systems with Feedforward Control of the Operating Concentration

    Directory of Open Access Journals (Sweden)

    Youngseung Na

    2015-09-01

    Full Text Available Most of the R&D on fuel cells for portable applications concentrates on increasing efficiencies and energy densities to compete with other energy storage devices, especially batteries. To improve the efficiency of direct methanol fuel cell (DMFC systems, several modifications to system layouts and operating strategies are considered in this paper, rather than modifications to the fuel cell itself. Two modified DMFC systems are presented, one with an additional inline mixer and a further modification of it with a separate tank to recover condensed water. The set point for methanol concentration control in the solution is determined by fuel efficiency and varies with the current and other process variables. Feedforward concentration control enables variable concentration for dynamic loads. Simulation results were validated experimentally with fuel cell systems.

  18. Modeling of the Transport Phenomena in Passive Direct Methanol Fuel Cells Using a Two-Phase Anisotropic Model

    Directory of Open Access Journals (Sweden)

    Zheng Miao

    2014-04-01

    Full Text Available The transport phenomena in a passive direct methanol fuel cell (DMFC were numerically simulated by the proposed two-dimensional two-phase nonisothermal mass transport model. The anisotropic transport characteristic and deformation of the gas diffusion layer (GDL were considered in this model. The natural convection boundary conditions were adopted for the transport of methanol, oxygen, and heat at the GDL outer surface. The effect of methanol concentration in the reservoir on cell performance was examined. The distribution of multiphysical fields in the membrane electrode assembly (MEA, especially in the catalyst layers (CLs, was obtained and analyzed. The results indicated that transport resistance for the methanol mainly existed in the MEA while that for oxygen and heat was primarily due to natural convection at the GDL outer surface. Because of the relatively high methanol concentration, the local reaction rate in CLs was mainly determined by the overpotential. Methanol concentration between 3 M and 4 M was recommended for passive liquid feed DMFC in order to achieve a balance between the cell performance and the methanol crossover.

  19. Mould Design and Material selection for Film Insert Moulding of Direct Methanol Fuel Cell Packaging

    DEFF Research Database (Denmark)

    Wöhner, Timo; Senkbeil, S.; Olesen, T. L.

    2015-01-01

    This paper presents the mould design for an injection moulding (IM) process for the production of a methanol container for the use in small, passive Direct Methanol Fuel Cell (DMFC) systems, which are intended to be used in behind-the-ear hearing aid systems. One of the crucial properties...

  20. New polymeric electrolyte membranes based on proton donor proton acceptor properties for direct methanol fuel cells

    NARCIS (Netherlands)

    Manea, G.C.; Mulder, M.H.V.

    2002-01-01

    In order to reduce the high methanol permeability of membranes in a direct methanol fuel cell application new and better materials are still required. In this paper membranes made from polybenzimidazole/sulfonated polysulfone are given and compared with homopolymer membranes made from sulfonated pol

  1. Characterization of polymer blends PES/SPSf and PES/SPEEK for direct methanol fuel cells

    NARCIS (Netherlands)

    Manea, G.C.; Mulder, M.H.V.

    2002-01-01

    Existing polymer electrolyte membranes (PEMs) applied for hydrogen fuel cells are frequently not suitable for direct methanol fuel cells due to the high methanol permeability. Therefore, new materials are required and in order to avoid laborious fuel cell experiments with a so-called membrane–electr

  2. A self-supported 40W direct methanol fuel cell system

    Indian Academy of Sciences (India)

    A Manokaran; R Vijayakumar; T N Thomman; P Sridhar; S Pitchumani; A K Shukla

    2011-05-01

    A self-supported 40W Direct Methanol Fuel Cell (DMFC) system has been developed and performance tested. The auxiliaries in the DMFC system comprise a methanol sensor, a liquid-level indicator, and fuel and air pumps that consume a total power of about 5W. The system has a 15-cell DMFC stack with active electrode-area of 45 cm2. The self-supported DMFC system addresses issues related to water recovery from the cathode exhaust, and maintains a constant methanol-feed concentration with thermal management in the system. Pure methanol and water from cathode exhaust are pumped to the methanol-mixing tank where the liquid level is monitored and controlled with the help of a liquid-level indicator. During the operation, methanol concentration in the feed solution at the stack outlet is monitored using a methanol sensor, and pure methanol is added to restore the desired methanol concentration in the feed tank by adding the product water from the cathode exhaust. The feed-rate requirements of fuel and oxidant are designed for the stack capacity of 40W. The self-supported DMFC system is ideally suited for various defense and civil applications and, in particular, for charging the storage batteries.

  3. Direct Electron Transfer of Methanol Dehydrogenase with Carbon Nanotubes

    OpenAIRE

    2009-01-01

    Modern day portable devices require ever increasing amount of energy. Fuel cells are one answer to demand for longer use times and quick recharge independent of an electric network. The use of hydrogen fuel cells for these kinds of applications has not been widespread, because storage of a required volume of hydrogen gas has been expensive or complicated. One solution to this is producing hydrogen in-situ from more easily storable compounds, e.g. methanol or ethanol. Reformers using inorganic...

  4. Micropump Fuel Mix Control for Novel Miniature Direct Methanol Fuel Cells Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Energies and Power Densities of Direct Methanol Fuel Cells (DMFCs) are limited by the size and weight associated with the liquid pump, which must circulate the...

  5. Mixed phase Pt-Ru catalyst for direct methanol fuel cell anode by flame aerosol synthesis

    DEFF Research Database (Denmark)

    Chakraborty, Debasish; Bischoff, H.; Chorkendorff, Ib

    2005-01-01

    A spray-flame aerosol catalyzation technique was studied for producing Pt-Ru anode electrodes for the direct methanol fuel cell. Catalysts were produced as aerosol nanoparticles in a spray-flame reactor and deposited directly as a thin layer on the gas diffusion layer. The as-prepared catalyst......Ru1/Vulcan carbon. The kinetics of methanol oxidation on the mixed phase catalyst was also explored by electrochemical impedance spectroscopy. (c) 2005 The Electrochemical Society....

  6. Modeling of the anode side of a direct methanol fuel cell with analytical solutions

    CERN Document Server

    Mosquera, Martín A

    2010-01-01

    In this work, analytical solutions were derived (for any methanol oxidation reaction order) for the profiles of methanol concentration and proton current density by assuming diffusion mass transport mechanism, Tafel kinetics, and fast proton transport in the anodic catalyst layer of a direct methanol fuel cell. An expression for the Thiele modulus that allows to express the anodic overpotential as a function of the cell current, and kinetic and mass transfer parameters was obtained. For high cell current densities, it was found that the Thiele modulus ($\\phi^2$) varies quadratically with cell current density; yielding a simple correlation between anodic overpotential and cell current density. Analytical solutions were derived for the profiles of both local methanol concentration in the catalyst layer and local anodic current density in the catalyst layer. Under the assumptions of the model presented here, in general, the local methanol concentration in the catalyst layer cannot be expressed as an explicit fun...

  7. Design of a stable and methanol resistant membrane with cross-linked multilayered polyelectrolyte complexes for direct methanol fuel cells

    Science.gov (United States)

    Wang, Jing; Zhao, Chengji; Lin, Haidan; Zhang, Gang; Zhang, Yang; Ni, Jing; Ma, Wenjia; Na, Hui

    Sulfonated poly (arylene ether ketone) bearing carboxyl groups (SPAEK-C) membranes have been prepared as proton exchange membranes for applications in direct methanol fuel cells (DMFCs). Multilayered polyelectrolyte complexes (PECs) which applied as methanol barrier agents are prepared by alternate deposition of the oppositely charged amino-containing poly (ether ether ketone) (Am-PEEK) and the highly sulfonated SPAEK-C via a layer-by-layer method. The cross-linked PEC (c-PEC) is derived from a simple heat-induced cross-linking reaction between Am-PEEK and SPAEK-C. Fourier transform infrared spectroscopy confirms that Am-PEEK and SPAEK-C are assembled successfully in the multilayers. The morphology of the membranes is studied by scanning electron microscopy, which shows the presence of the thin layers coated on the SPAEK-C membrane. After PEC and c-PEC modification, the methanol permeability decreases obviously when compared to that of the pristine membrane. Notably, improved proton conductivities are obtained for the PEC modified membranes in comparison with the pristine membrane. Moreover, the selectivity of these modified membranes is one order of magnitude higher than that of Nafion 117. The thermal stability, oxidative stability, water uptake and swelling of PEC and c-PEC modified membranes are also investigated.

  8. Characterization of Polyethylene-Graft-Sulfonated Polyarylsulfone Proton Exchange Membranes for Direct Methanol Fuel Cell Applications

    Directory of Open Access Journals (Sweden)

    Hyung Kyu Kim

    2015-12-01

    Full Text Available This paper examines polymer film morphology and several important properties of polyethylene-graft-sulfonated polyarylene ether sulfone (PE-g-s-PAES proton exchange membranes (PEMs for direct methanol fuel cell applications. Due to the extreme surface energy differences between a semi-crystalline and hydrophobic PE backbone and several amorphous and hydrophilic s-PAES side chains, the PE-g-s-PAES membrane self-assembles into a unique morphology, with many proton conductive s-PAES channels embedded in the stable and tough PE matrix and a thin hydrophobic PE layer spontaneously formed on the membrane surfaces. In the bulk, these membranes show good mechanical properties (tensile strength >30 MPa, Young’s modulus >1400 MPa and low water swelling (λ < 15 even with high IEC >3 mmol/g in the s-PAES domains. On the surface, the thin hydrophobic and semi-crystalline PE layer shows some unusual barrier (protective properties. In addition to exhibiting higher through-plane conductivity (up to 160 mS/cm than in-plane conductivity, the PE surface layer minimizes methanol cross-over from anode to cathode with reduced fuel loss, and stops the HO• and HO2• radicals, originally formed at the anode, entering into PEM matrix. Evidently, the thin PE surface layer provides a highly desirable protecting layer for PEMs to reduce fuel loss and increase chemical stability. Overall, the newly developed PE-g-s-PAES membranes offer a desirable set of PEM properties, including conductivity, selectivity, mechanical strength, stability, and cost-effectiveness for direct methanol fuel cell applications.

  9. Cost Analysis of Direct Methanol Fuel Cell Stacks for Mass Production

    Directory of Open Access Journals (Sweden)

    Mauro Francesco Sgroi

    2016-11-01

    Full Text Available Fuel cells are very promising technologies for efficient electrical energy generation. The development of enhanced system components and new engineering solutions is fundamental for the large-scale deployment of these devices. Besides automotive and stationary applications, fuel cells can be widely used as auxiliary power units (APUs. The concept of a direct methanol fuel cell (DMFC is based on the direct feed of a methanol solution to the fuel cell anode, thus simplifying safety, delivery, and fuel distribution issues typical of conventional hydrogen-fed polymer electrolyte fuel cells (PEMFCs. In order to evaluate the feasibility of concrete application of DMFC devices, a cost analysis study was carried out in the present work. A 200 W-prototype developed in the framework of a European Project (DURAMET was selected as the model system. The DMFC stack had a modular structure allowing for a detailed evaluation of cost characteristics related to the specific components. A scale-down approach, focusing on the model device and projected to a mass production, was used. The data used in this analysis were obtained both from research laboratories and industry suppliers specialising in the manufacturing/production of specific stack components. This study demonstrates that mass production can give a concrete perspective for the large-scale diffusion of DMFCs as APUs. The results show that the cost derived for the DMFC stack is relatively close to that of competing technologies and that the introduction of innovative approaches can result in further cost savings.

  10. A Graphite Oxide Paper Polymer Electrolyte for Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    Ravi Kumar

    2011-01-01

    Full Text Available A flow directed assembly of graphite oxide solution was used in the formation of free-standing graphene oxide paper of approximate thickness of 100 μm. The GO papers were characterised by XRD and SEM. Electrochemical characterization of the GO paper membrane electrode assembly revealed proton conductivities of 4.1 × 10−2 S cm−1 to 8.2 × 10−2 S cm−1 at temperatures of 25–90°C. A direct methanol fuel cell, at 60°C, gave a peak power density of 8 mW cm−2 at a current density of 35 mA cm−2.

  11. Development and characterisation of a portable direct methanol fuel cell stack

    Energy Technology Data Exchange (ETDEWEB)

    Oedegaard, A.

    2005-11-21

    This thesis deals with the development and characterisation of a portable direct methanol fuel cell stack. In addition, calculations of the transport of methanol and water in the membrane are compared with experimentally determined values. It also includes investigations of the behaviour of single-cells and some of its components, as the anode gas diffusion layer and the anode flow-field. For the addition of methanol to the anode feed loop, a passive concept based on a permeable tube was developed and verified by both experiments and simulations. (orig.)

  12. Characterisation of micro direct methanol fuel cells with silicon plate supported integrated ionomer membranes

    DEFF Research Database (Denmark)

    Larsen, Jackie Vincent; Dalslet, Bjarke Thomas; Kallesee, C.

    2013-01-01

    This work deals with the investigation and fabrication of Micro Direct Methanol Fuel Cells (μDMFC). They are investigated as a possible alternative for zinc-air batteries in small size consumer devices such as hearing aids. In such devices the conventional rechargeable batteries such as lithium......-ion batteries have insufficiently low energy density in the range 240 Wh/L to 300 Wh/L Methanol is a promising fuel for such devices due to the high energy density, with pure methanol having an energy density of 4400 Wh/L. Using a liquid fuel also allows refueling, which can be achieved much faster than battery...

  13. Nafion/PTFE/silicate composite membranes for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Li-Ning; Chen, Li-Chun; Yu, T. Leon; Lin, Hsiu-Li [Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 32026 (Taiwan)

    2006-10-27

    Poly(tetrafluoro ethylene) (PTFE)/Nafion composite membranes (PN composite membranes) were prepared by impregnating micro-porous PTFE membranes in Nafion/2-propanol/water solutions. The PN composite membranes were then further impregnated with tetraethoxysilane (TEOS) solutions to prepare PTFE/Nafion/silicate (PNS) composite membranes. The influence of hybridizing silicate into the PN membranes on their direct methanol fuel cell (DMFC) performance and methanol crossover was investigated. Silicate in PN membranes causes reduction both in proton conductivity and methanol crossover of membranes. Thus PNS had a higher voltage than PN at low current densities due to the lower methanol crossover of PNS. However, at high current densities, PNS had a lower voltage than PN due to the higher resistance to proton transference of PNS. The range of lower current densities where PNS had a higher voltage than PN was i=0-120mAcm{sup -2} when the methanol feed concentration was 2M. This lower current density range became broader as the methanol feed concentration was increased, and it was broadened to i=0-190mAcm{sup -2} as the methanol feed concentration was increased to 5M. A comparison of the methanol crossover on the DMFC performance of PN and PNS with Nafion-112 was also studied. We showed that Nafion-112 exhibits higher methanol electro-osmosis than PN and PNS. Thus at a high current density, the higher methanol crossover via electro-osmosis caused Nafion-112 to have a lower voltage than PN and PNS. (author)

  14. Relating Direct Methanol Fuel Cell Performance to Measurements in a Liquid Half Cell

    DEFF Research Database (Denmark)

    Pedersen, Christoffer Mølleskov; Tynelius, Oskar; Lund-Olesen, Torsten

    2015-01-01

    Direct methanol fuel cells (DMFC) could act as a replacement for batteries in low power electronics. For instance, micro—DMFC’s could be used to power hearing instruments[1]. The power output of a DMFC is limited by the sluggish kinetics of both the methanol oxidation reaction (MOR) on the anode ...... Cells Bull. 2012 (2012) 12–16. doi:10.1016/S1464-2859(12)70367-X....

  15. Nafion/PTFE composite membranes for direct methanol fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Hsiu-Li; Yu, T. Leon; Chen, Li-Chung [Department of Chemical Engineering and Materials Science, Yuan Ze University, Nei-Li, Taoyuan 32026 (Taiwan); Huang, Li-Ning; Shen, Kun-Sheng; Jung, Guo-Bin [Fuel Cell Center, Yuan Ze University, Nei-Li, Taoyuan 32026 (Taiwan)

    2005-10-04

    Using dynamic light scattering and scanning electron microscope (SEM), it is shown that a high-carbon-number alcohol/water, i.e., 2-propanol/water, mixed solvent is more effective than low-carbon-number alcohol/water, i.e., ethanol/water and methanol/water, mixed solvents in dispersing Nafion molecules. Thus, it is a better solvent for the preparation of Nafion/PTFE (poly(tetrafluoroethylene)) composite membranes. The performance of direct methanol fuel cells (DMFCs) with a Nafion/PTFE composite membrane, which was prepared in-house, a commercial Nafion-117 membrane, or a commercial Nafion-112 membrane were investigated by feeding various concentrations, i.e., 2-5M, of methanol to the anode. The Nafion/PTFE composite membrane gave a better DMFC performance than that obtained with Nafion-117 or Nafion-112 membranes. Using a DMFC model and varying the methanol concentration at the anode, cell voltage data were analyzed with respect to methanol concentration and cell current. The results indicate that inserting porous PTFE into Nafion polymer causes a reduction not only in methanol diffusion cross-over but also in the electro-osmosis of methanol cross-over in the membrane. (author)

  16. Palladium-Based Catalysts as Electrodes for Direct Methanol Fuel Cells: A Last Ten Years Review

    Directory of Open Access Journals (Sweden)

    Juan Carlos Calderón Gómez

    2016-08-01

    Full Text Available Platinum-based materials are accepted as the suitable electrocatalysts for anodes and cathodes in direct methanol fuel cells (DMFCs. Nonetheless, the increased demand and scarce world reserves of Pt, as well as some technical problems associated with its use, have motivated a wide research focused to design Pd-based catalysts, considering the similar properties between this metal and Pt. In this review, we present the most recent advancements about Pd-based catalysts, considering Pd, Pd alloys with different transition metals and non-carbon supported nanoparticles, as possible electrodes in DMFCs. In the case of the anode, different reported works have highlighted the capacity of these new materials for overcoming the CO poisoning and promote the oxidation of other intermediates generated during the methanol oxidation. Regarding the cathode, the studies have showed more positive onset potentials, as fundamental parameter for determining the mechanism of the oxygen reduction reaction (ORR and thus, making them able for achieving high efficiencies, with less production of hydrogen peroxide as collateral product. This revision suggests that it is possible to replace the conventional Pt catalysts by Pd-based materials, although several efforts must be made in order to improve their performance in DMFCs.

  17. Development of a Direct Methanol Fuel Cell with Lightweight Disc Type Current Collectors

    Directory of Open Access Journals (Sweden)

    Yean-Der Kuan

    2014-05-01

    Full Text Available The direct methanol fuel cell (DMFC adopts methanol solution as a fuel suitable for low power portable applications. A miniature, lightweight, passive air-breathing design is therefore desired. This paper presents a novel planar disc-type DMFC with multiple cells containing a novel developed lightweight current collector at both the anode and cathode sides. The present lightweight current collector adopts FR4 Glass/Epoxy as the substrate with the current collecting areas located at the corresponding membrane electrolyte assembly (MEA areas. The current collecting areas are fabricated by sequentially coating a corrosion resistant layer and electrical conduction layer via the thermal evaporation technique. The anode current collector has carved flow channels for fuel transport and production. The cathode current collector has drilled holes for passive air breathing. In order to ensure feasibility in the present concept a 3-cell prototype DMFC module with lightweight disc type current collectors is designed and constructed. Experiments were conducted to measure the cell performance. The results show that the highest cell power output is 54.88 mW·cm−2 and successfully demonstrate the feasibility of this novel design.

  18. Preparation of Sulfonated PVA-TMSP Membranes for Direct Methanol Fuel Cell

    Directory of Open Access Journals (Sweden)

    Haryadi

    2012-08-01

    Full Text Available Novel preparation and characterization of sulfonated polyvinyl alcohol (PVA–trimethoxysilyl propanethiol (TMSP membranes for direct methanol fuel cell (DMFC application have been investigated. Preparation of sulfonated PVA-TMSP membrane was conducted by crosslinking steps using sol-gel method and a catalyst of concentrated HCl. TMSP concentrations were varied from 1% to 3%. The gel solution was cast on to the membrane metal plate to obtain membrane sheets. The membrane was then oxidized in H2O2 concentrations of (10-30% to convert the mercapto groups into sulfonate group. Investigations of the cross-linking process and the existence of sulfonate group were conducted by infrared spectroscopy as shown for frequencies at 1140–1200/cm and 1200–1145/cm respectively. The scanning electron microscope–energy dispersive X-rays (SEM–EDX of the membranes indicated that the distribution of silica particles from sol–gel reaction products was uneven due to the fast exchange rate of condensation. The degree of swelling decreased as methanol concentrations increase for sulfonated PVA–TMSP membrane which opposed toward the value of commercial Nafion membrane. The maximum value of ion exchange capacity of the membrane was 1.82 mmol/g whereas the highest proton conductivity was 3.9 x 10-4 S/cm. Therefore it can be concluded that the membrane was a potential candidate for application in DMFC.

  19. Influencing parameters of water and methanol transport in a big direct methanol fuel cell; Einflussgroessen auf den Wasser- und Methanoltransport einer groesseren Direkt-Methanol Brennstoffzelle

    Energy Technology Data Exchange (ETDEWEB)

    Schonert, Morten

    2008-07-01

    The author investigated the influencing parameters of water and methanol transport in a big direct methanol fuel cell (Pel > 1 kW) with the intention of making the direct methanol fuel cell system water-autonomous. As water is consumed during the electrochemical reaction on the anode while more water is produced on the cathode, the difference must be removed via the air. Any further water produced on the cathode must be condensed and recirculated to the anode. With increasing ambient temperature, the air volume flow must be reduced because otherwise more water would be removed than is acceptable. Low air volume flow on the cathode causes unstable cell voltage, which is also assumed to be caused by excess water production. For this reason, an attempt was made to prevent excess water production on the cathode by a system engineering approach. It was found that at the low air volume flow required for water autonomy, water permeation through the membrane-electrode aggregate (MEA) depends on the uptake capacity and on the time of residue of air over the cathode and less on the cathode material. Water permeation stops when the concentration gradient is balanced. Apart from the water permeation, there is also water transport through the Nafion {sup registered} membrane, i.e. so-called electroosmotic drag (ESD). This is an active transport mechanism that can also work against a concentration gradient. It could be shown that the EOD can be reduced by using water-impermeable materials for the gas diffusion layer on the anode. This will reduce the water volume that reaches the membrane, i.e. the water on the cathode. On the other hand, there was no measurable effect of the cathode design on water or methanol transport. The electrochemical performance of the membrane-electrode units under investigation was robust in case of many influencing parameters, e.g. dispersion, the conditions of MEA fabrication by hot pressing, themembrane thickness and the rate of methanol permeation

  20. Experimental Validation of Methanol Crossover in a Three-dimensional, Two-Fluid Model of a Direct Methanol Fuel Cell

    DEFF Research Database (Denmark)

    Olesen, Anders Christian; Berning, Torsten; Kær, Søren Knudsen

    2012-01-01

    in the ionomer phase of the catalytic layer, and detailed membrane transport of methanol and water. In order to verify the models ability to predict methanol crossover, simulation results are compared with experimental measurements under different current densities along with air and methanol stoichiometries...

  1. Experimental Investigation of a Direct Methanol Fuel Cell with Hilbert Fractal Current Collectors

    Directory of Open Access Journals (Sweden)

    Jing-Yi Chang

    2014-01-01

    Full Text Available The Hilbert curve is a continuous type of fractal space-filling curve. This fractal curve visits every point in a square grid with a size of 2×2, 4×4, or any other power of two. This paper presents Hilbert fractal curve application to direct methanol fuel cell (DMFC current collectors. The current collectors are carved following first, second, and third order Hilbert fractal curves. These curves give the current collectors different free open ratios and opening perimeters. We conducted an experimental investigation into DMFC performance as a function of the free open ratio and opening perimeter on the bipolar plates. Nyquist plots of the bipolar plates are made and compared using electrochemical impedance spectroscopy (EIS experiments to understand the phenomena in depth. The results obtained in this paper could be a good reference for future current collector design.

  2. Direct methanol fuel cells for transportation applications. Quarterly technical report, June 1996--September 1996

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, T.F.; Kunz, H.R.; Moore, R.

    1996-11-01

    The purpose of this research and development effort is to advance the performance and viability of direct methanol fuel cell technology for light-duty transportation applications. For fuel cells to be an attractive alternative to conventional automotive power plants, the fuel cell stack combined with the fuel processor and ancillary systems must be competitive in terms of both performance and costs. A major advantage for the direct methanol fuel cell is that a fuel processor is not required. A direct methanol fuel cell has the potential of satisfying the demanding requirements for transportation applications, such as rapid start-up and rapid refueling. The preliminary goals of this effort are: (1) 310 W/l, (2) 445 W/kg, and (3) potential manufacturing costs of $48/kW. In the twelve month period for phase 1, the following critical areas will be investigated: (1) an improved proton-exchange membrane that is more impermeable to methanol, (2) improved cathode catalysts, and (3) advanced anode catalysts. In addition, these components will be combined to form membrane-electrode assemblies (MEA`s) and evaluated in subscale tests. Finally a conceptual design and program plan will be developed for the construction of a 5 kW direct methanol stack in phase II of the program.

  3. Direct Vapor Phase Carbonylation of Methanol over NiCl2/C Catalyst

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@ Introduction The carbonylation of alcohols via homogenous catalysis is important in manufacturing acetic acid and higher carboxylic acids and their esters[1,2]. The main route to produce acetic acid is to make methanol carbonylated by means of the Monsanto and BP process in which a homogeneous rhodium catalyst is used. Although the homogeneous carbonylation of methanol is a highly selective process, it is affected by the disadvantages associated with a highly corrosive reaction medium due to the use of methyl iodide as the promoter, and the difficulty of the product separation[3]. The use of a heterogeneous catalyst seems very interesting and attractive to us[4], especially the direct vapor phase carbonylation of methanol without a halide promoter is of considerable importance and is strong incentive economically. There has, however, been very little success in finding either heterogeneous or homogeneous catalysts that can catalyze the reaction effectively without the addition of a promoter[5,6]. According to the known carbonylation mechanism[7,8], the methyl iodide directly carbonylates with CO to from MeCOI which interacts with methanol(MeOH) to produce methyl acetate(MeCOOMe) and HI, and then MeOH reacts with HI to from CH3I. In fact, this carbonylation reaction is the indirect catalytic carbonylation of methanol[9]. In this work, a novel catalyst for the direct vapor phase carbonylation of methanol without the addition of any halide in the feed as a promoter was investigated. Compared to the known liquid phase methanol carbonylation process, some advantages of this vapor phase reaction are as follows:

  4. Behavioral pattern of a monopolar passive direct methanol fuel cell stack

    Science.gov (United States)

    Kim, Young-Jin; Bae, Byungchan; Scibioh, M. Aulice; Cho, EunAe; Ha, Heung Yong

    A passive, air-breathing, monopolar, liquid feed direct methanol fuel cell (DMFC) stack consisting of six unit cells with no external pump, fan or auxiliary devices to feed the reactants has been designed and fabricated for its possible employment as a portable power source. The configurations of the stack of monopolar passive feed DMFCs are different from those of bipolar active feed DMFCs and therefore its operational characteristics completely vary from the active ones. Our present investigation primarily focuses on understanding the unique behavioral patterns of monopolar stack under the influence of certain operating conditions, such as temperature, methanol concentration and reactants feeding methods. With passive reactants supply, the temperature of the stack and open circuit voltage (OCV) undergo changes over time due to a decrease in concentration of methanol in the reservoir as the reaction proceeds. Variations in performance and temperature of the stack are mainly influenced by the concentration of methanol. Continuous operation of the passive stack is influenced by the supply of methanol rather than air supply or water accumulation at the cathode. The monopolar stack made up of six unit cells exhibits a total power of 1000 mW (37 mW cm -2) with 4 M methanol under ambient conditions.

  5. Low-Pt-Content Anode Catalyst for Direct Methanol Fuel Cells

    Science.gov (United States)

    Narayanan, Sekharipuram; Whitacre, Jay

    2008-01-01

    Combinatorial experiments have led to the discovery that a nanophase alloy of Pt, Ru, Ni, and Zr is effective as an anode catalyst material for direct methanol fuel cells. This discovery has practical significance in that the electronic current densities achievable by use of this alloy are comparable or larger than those obtained by use of prior Pt/Ru catalyst alloys containing greater amounts of Pt. Heretofore, the high cost of Pt has impeded the commercialization of direct methanol fuel cells. By making it possible to obtain a given level of performance at reduced Pt content (and, hence, lower cost), the discovery may lead to reduction of the economic impediment to commercialization.

  6. Nuclear magnetic resonance spectroscopic investigation of anode exhaust of direct methanol fuel cells without isotope enrichment

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Young Seok; Hwang, Reo Yun; Han, Ochee [Western Seoul Center, Korea Basic Science Institute, Seoul (Korea, Republic of)

    2016-12-15

    Fuel cells are devices that electrochemically convert the chemical energy of fuels such as natural gas, gasoline, and methanol, into electricity. Fuel cells more efficiently use energy than internal combustion engines and do not produce undesirable pollutants, such as NO{sub x} ,SO{sub x} and particulates. Fuel cells can be distinguished from one another by their electrolytes. Among the various direct alcohol fuel cells, direct methanol fuel cells (DMFCs) have been developed most. However, DMFCs have several practical problems such as methanol crossove r from an anode to a cathode and slow methanol oxidation reaction rates. Therefore, understanding the electrochemical reaction mechanisms of DMFCs may provide clues to solve these problems, and various analytical methods have been employed to examine these mechanisms. We demonstrated that {sup 1}H and {sup 13}C NMR spectroscopy can be used for analyzing anode exhausts of DMFCs operated with methanol without any isotope enrichment. However, the low sensitivity of NMR spectroscopy hindered our efforts to detect minor reaction intermediates. Therefore, sensitivity enhancement techniques such as dynamic nuclear polarization (DNP) NMR methods and/or presaturation methods to increase the dynamic range of the proton spectra by pre-saturating large water signals, are expected to be useful to detect low-concentration species.

  7. Challenges in Design of an Orientation free Micro Direct Methanol Fuel Cell (µDMFC)

    DEFF Research Database (Denmark)

    Omidvarnia, Farzaneh; Hansen, Hans Nørgaard; Hales, Jan Harry

    2014-01-01

    the challenges in design and manufacturing of a micro direct methanol fuel cell (μDMFC) as the power generator in hearing aid devices is investigated. Among the different challenges in design for μDMFC, the CO2 bubble management and orientation independency of the cell are addressed by proposing a spring loaded...

  8. A quasi-direct methanol fuel cell system based on blend polymer membrane electrolytes

    DEFF Research Database (Denmark)

    Li, Qingfeng; Hjuler, Hans Aage; Hasiotis, C.

    2002-01-01

    , compared to less than 100 ppm CO for the Nafion-based technology at 80degrees C. The high CO tolerance makes it possible to use the reformed hydrogen directly from a simple methanol reformer without further CO removal. That both the fuel cell and the methanol reformer operate at temperatures around 200......On the basis of blend polymer electrolytes of polybenzimidazole and sulfonated polysulfone, a polymer electrolyte membrane fuel cell was developed with an operational temperature up to 200degrees C. Due to the high operational temperature, the fuel cell can tolerate 1.0-3.0 vol % CO in the fuel...

  9. Pt/onion-like fullerenes as catalyst for direct methanol fuel cell

    Institute of Scientific and Technical Information of China (English)

    GUO Junjie; YANG Xiaowei; YAO Yanli; WANG Xiaomin; LIU Xuguang; XU Bingshe

    2006-01-01

    Onion-like fullerenes synthesized by arc discharge in water were used as support of Pt nanoparticles as electrocatalytic materials for direct methanol fuel cell. Uniform platinum nanoparticles with the average diameter of about 4.3 nm were well dispersed on the surface of onion-like fullerenes by impregnation-reduction method. The morphologies and microstructures of the as-prepared composites were studied by means of XRD and TEM. Electrochemical analysis shows that this kind of nano material may be an excellent candidate to be used as the support of catalyst for methanol electrochemical oxidation.

  10. Novel Metal Oxide Support with Water Activation Ability for Use in Direct Methanol Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    WANG Qingjing; WEI Ang; ZHAO Xiaohui; ZHANG Shuyong

    2009-01-01

    A new principle for designing catalyst supports with water activation ability was proposed.According to this principle,stabilized nickel(+3)oxides with different dopants were tested as possible support and promoter for Pt catalyst in direct methanol fuel cells.It was found that the chemical and electrochemical stabilities of these novel supports in acidic solution were sufficient.The support doped with Ai(+3)has catalytic activity towards methanol electrooxidation while that doped with Co(+3)can improve both activity and poisoning tolerance of the Pt catalyst.

  11. Mould Design and Material selection for Film Insert Moulding of Direct Methanol Fuel Cell Packaging

    DEFF Research Database (Denmark)

    Wöhner, Timo; Senkbeil, S.; Olesen, T. L.;

    2015-01-01

    of this container is to enable venting of CO2, which is produced during the use of the DMFC system. This attribute is realized by a functional film insert in the form of a microporous, oleophobic membrane, which covers a venting hole in the injection moulded part of the container. The mould was designed to allow......This paper presents the mould design for an injection moulding (IM) process for the production of a methanol container for the use in small, passive Direct Methanol Fuel Cell (DMFC) systems, which are intended to be used in behind-the-ear hearing aid systems. One of the crucial properties...

  12. High Proton Conducting SPEEK/SiO2/PWA Composite Membranes for Direct Methanol Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    ZHANG Gaowen; JIANG Jiuxin; LIU Jianing

    2011-01-01

    Sulfonated polyether ether ketone (SPEEK) based composite membranes for direct methanol fuel cell (DMFC) application were prepared by sol-gel reaction of tetraethoxysilane (TEOS) in the SPEEK matrix and the incorporation of phosphotungstic acid (PWA). The conductivity of the developed membranes was determined by impedance spectroscopy and the methanol permeability through the membranes was obtained from diffuseness experiments. The SEM images show that the addition of SiO2 and the covalent cross-linking structure lead to fine PWA particles and more uniformly dispersion. The swelling of composite membranes remains in the range of 5%-8% at 30-90 ℃ and the effusion of PWA reduces significantly. The composite membranes show a good balance in higher proton conductivity and lower methanol permeation. The cell with composite membrane has higher open circuit voltage(0.728 V) and higher peak power density(45 mW/cm2) than that with Nation 117.

  13. A mixed-reactants solid-polymer-electrolyte direct methanol fuel cell

    Science.gov (United States)

    Scott, K.; Shukla, A. K.; Jackson, C. L.; Meuleman, W. R. A.

    Mixed-reactants solid-polymer-electrolyte direct methanol fuel cells (SPE-DMFCs) with a PtRu/C anode and a methanol-tolerant oxygen-reduction cathode catalyst have been assembled and have been subjected to galvanostatic polarisation studies. The oxygen-reduction cathode was either of the FeTMPP/C, CoTMPP/C, FeCoTMPP/C and RuSe/C. It was found that the SPE-DMFC with the RuSe/C cathode yielded the best performance. It has been possible to achieve power densities of approximately 50 and 20 mW/cm 2 while operating a mixed-reactants SPE-DMFC at 90 °C with oxygen and air fed cathodes, respectively. Interestingly, these SPE-DMFCs exhibit no parasitic oxidation of methanol with oxygen.

  14. Direct partial oxidation of methane to methanol: Reaction zones and role of catalyst location

    Institute of Scientific and Technical Information of China (English)

    Qijian Zhang; Dehua He; Qiming Zhu

    2008-01-01

    Direct partial oxidation of methane to methanol was investigated in a specially designed reactor. Methanol yield of about 7%-8% was obtained in gas phase partial oxidation. It was proposed that the reactor could be divided into three reaction zones, namely pre-reaction zone, fierce reaction zone, and post-reaction zone, when the temperature was high enough to initiate a reaction. The oxidation of methane proceeded and was completed mostly in the fierce reaction zone. When the reactant mixture entered the post-reaction zone, only a small amount of produced methanol would bring about secondary reactions, because molecular oxygen had been exhausted in the fierce reaction zone. A catalyst, if necessary, should be placed either in the pre-reaction zone, to initiate a partial oxidation reaction at a lower temperature, or in the fierce reaction zone to control the homogeneous free radical reaction.

  15. High-temperature passive direct methanol fuel cells operating with concentrated fuels

    Science.gov (United States)

    Zhao, Xuxin; Yuan, Wenxiang; Wu, Qixing; Sun, Hongyuan; Luo, Zhongkuan; Fu, Huide

    2015-01-01

    Conventionally, passive direct methanol fuel cells (DMFC) are fed with diluted methanol solutions and can hardly be operated at elevated temperatures (>120 °C) because the ionic conductivity of Nafion-type proton exchange membranes depends strongly on water content. Such a system design would limit its energy density and power density in mobile applications. In this communication, a passive vapor feed DMFC capable of operating with concentrated fuels at high temperatures is reported. The passive DMFC proposed in this work consists of a fuel reservoir, a perforated silicone sheet, a vapor chamber, two current collectors and a membrane electrode assembly (MEA) based on a phosphoric acid doped polybenzimidazole (PBI) membrane. The experimental results reveal that the methanol crossover through a PBI membrane is substantially low when compared with the Nafion membranes and the PBI-based passive DMFC can yield a peak power density of 37.2 mW cm-2 and 22.1 mW cm-2 at 180 °C when 16 M methanol solutions and neat methanol are used respectively. In addition, the 132 h discharge test indicates that the performance of this new DMFC is quite stable and no obvious performance degradation is observed after activation, showing its promising applications in portable power sources.

  16. On the actual cathode mixed potential in direct methanol fuel cells

    Science.gov (United States)

    Zago, M.; Bisello, A.; Baricci, A.; Rabissi, C.; Brightman, E.; Hinds, G.; Casalegno, A.

    2016-09-01

    Methanol crossover is one of the most critical issues hindering commercialization of direct methanol fuel cells since it leads to waste of fuel and significantly affects cathode potential, forming a so-called mixed potential. Unfortunately, due to the sluggish anode kinetics, it is not possible to obtain a reliable estimation of cathode potential by simply measuring the cell voltage. In this work we address this limitation, quantifying the mixed potential by means of innovative open circuit voltage (OCV) tests with a methanol-hydrogen mixture fed to the anode. Over a wide range of operating conditions, the resulting cathode overpotential is between 250 and 430 mV and is strongly influenced by methanol crossover. We show using combined experimental and modelling analysis of cathode impedance that the methanol oxidation at the cathode mainly follows an electrochemical pathway. Finally, reference electrode measurements at both cathode inlet and outlet provide a local measurement of cathode potential, confirming the reliability of the innovative OCV tests and permitting the evaluation of cathode potential up to typical operating current. At 0.25 A cm-2 the operating cathode potential is around 0.85 V and the Ohmic drop through the catalyst layer is almost 50 mV, which is comparable to that in the membrane.

  17. The Methanol Economy Project

    Energy Technology Data Exchange (ETDEWEB)

    Olah, George [Univ. of Southern California, Los Angeles, CA (United States); Prakash, G. K. [Univ. of Southern California, Los Angeles, CA (United States)

    2014-02-01

    The Methanol Economy Project is based on the concept of replacing fossil fuels with methanol generated either from renewable resources or abundant natural (shale) gas. The full methanol cycle was investigated in this project, from production of methanol through bromination of methane, bireforming of methane to syngas, CO2 capture using supported amines, co-electrolysis of CO2 and water to formate and syngas, decomposition of formate to CO2 and H2, and use of formic acid in a direct formic acid fuel cell. Each of these projects achieved milestones and provided new insights into their respective fields.

  18. An Investigation of Palladium Oxygen Reduction Catalysts for the Direct Methanol Fuel Cell

    Directory of Open Access Journals (Sweden)

    G. F. Álvarez

    2011-01-01

    Full Text Available A comparative study of Pd and Pt was carried out in DMFC using different methanol concentrations and under different operating conditions. Cell performance was compared at methanol concentrations of 1, 3, 5, and 7 M and at temperatures of 20, 40, and 60°C. Homemade Pd nanoparticles were prepared on Vulcan XC-72R using ethylene glycol as the reducing agent at pH 11. The resulting catalyst, Pd/C, with metal nanoparticles of approximately 6 nm diameter, was tested as a cathode catalyst in DMFC. At methanol concentrations of 5 M and higher, the Pd cathode-based cell performed better than that with Pt at 60°C with air.

  19. Methanol Electro-oxidation of the Direct Methanol Fuel Cell%直接甲醇燃料电池中的甲醇电催化氧化

    Institute of Scientific and Technical Information of China (English)

    马紫峰; 冷拥军; 蒋淇忠; 廖小珍

    1999-01-01

      Kinetic limitations of methanol electro-oxidation for the direct methanol fuel cell have been outlined. The mechanism of methanol electro-oxidation was analyzed. The effect of the operation temperature, pressure and various feed systems on the performance of the methanol electro-oxidation was also expounded.%  概要介绍了直接甲醇燃料电池中甲醇电催化氧化的动力学限制,分析了甲醇电催化氧化机理,阐明了工作温度、压力和进料方式对甲醇电催化氧化性能的影响关系。

  20. Evaluation of osmium-ruthenium carbonyl cluster compounds as a cathode in a passive direct methanol fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Castellanos, R.H.; Borja-Arco, E.; Uribe-Godinez, J.; Ramirez-Rivera, J.C. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Escobedo (Mexico)

    2006-07-01

    Methanol crossover is a major technical barrier to the application of direct methanol fuel cell (DMFC) technology. Methanol crossover causes a mixed potential on the cathode and reduces overall cell voltage. This paper studied the effect of methanol concentration on the performance of a passive DMFC using a different catalyst on the cathode. The membrane electrode assembly (MEA) was sandwiched between a current collector made of 316 stainless steel and a current collector made of aluminum (Al). Single cells were operated at room temperature and ambient pressure under passive conditions with varying concentrations of methanol. The cells were then analyzed to determine the effects of concentrations of methanol on their performance. Results showed that when 1.0 M methanol was used, the DMFC showed the highest voltage value. However, when higher concentrations of methanol were used, the voltage value decreased. Results also showed that performance of the passive DMFC improved through the use of an osmium (Os{sub x}Ru{sub y}(CO){sub n}) cathode when intermediated concentrations of methanol were used. It was concluded that optimal methanol concentrations ranged from 4 to 5 methanol molar. 3 refs., 2 figs.

  1. Modelling of solid polymer and direct methanol fuel cells: Phenomenological equations and analytical solutions

    Science.gov (United States)

    Kauranen, P. S.

    1993-04-01

    In the solid state concept of a direct methanol fuel cell (DMFC), methanol is directly oxidized at the anode of a solid polymer electrolyte fuel cell (SPEFC). Mathematical modelling of the transport and reaction phenomena within the electrodes and the electrolyte membrane is needed in order to get a closer insight into the operation of the fuel cell. In the work, macro-homogenous porous electrode and dilute solution theories are used to derive the phenomenological equations describing the transport and reaction mechanisms in a SPEFC single cell. The equations are first derived for a conventional H2/air SPEFC, and then extended for a DMFC. The basic model is derived in a one dimensional form in which it is assumed that species transport take place only in the direction crossing the cell sandwich. In addition, two dimensional descriptions of the catalyst layer are reviewed.

  2. Investigation of nano Pt and Pt-based alloys electrocatalysts for direct methanol fuel cells and their properties

    Directory of Open Access Journals (Sweden)

    Chunguang Suo

    2014-03-01

    Full Text Available The electrocatalysts used in micro direct methanol fuel cell (μDMFC, such as Pt/C and Pt alloy/C, prepared by liquid-phase NaBH4 reduction method have been investigated. XC-72 (Cobalt corp. Company, U.S.A is chosen as the activated carrier for the electrocatalysts to keep the catalysts powder in the range of several nanometers. The XRD, SEM, EDX analyses indicated that the catalysts had small particle size in several nanometers, in excellent dispersed phase and the molar ratio of the precious metals was found to be optimal. The performances of the DMFCs using cathodic catalyst with Pt percentage of 30wt% and different anodic catalysts (Pt-Ru, Pt-Ru-Mo were tested. The polarization curves and power density curves of the cells were measured to determine the optimal alloy composition and condition for the electrocatalysts. The results showed that the micro direct methanol fuel cell with 30wt% Pt/C as the cathodic catalyst and n(Pt:n(Ru:n(Mo = 3:2:2 PtRuMo/C as the anodic catalyst at room temperature using 2.0mol/L methanol solution has the best performances.

  3. Transient Response and Steady-State Analysis of the Anode of Direct Methanol Fuel Cells Based on Dual-Site Kinetics

    Directory of Open Access Journals (Sweden)

    Lei Xing

    2011-01-01

    Full Text Available An intrinsic time-dependent one-dimensional (1D model and a macro two-dimensional (2D model for the anode of the direct methanol fuel cell (DMFC are presented. The two models are based on the dual-site mechanism, which includes the coverage of intermediate species of methanol, OH, and CO (θM, θOH,Ru, and θCO,Pt on the surface of Pt and Ru. The intrinsic 1D model focused on the analysis of the effects of operating temperature, methanol concentration, and overpotential on the transient response. The macro 2D model emphasises the dimensionless distributions of methanol concentration, overpotential and current density in the catalyst layer which were affected by physical parameters such as thickness, specific area, and operating conditions such as temperature, bulk methanol concentration, and overpotential. The models were developed and solved in the PDEs module of COMSOL Multiphysics, giving good agreement with experimental data. The dimensionless distributions of methanol concentration, overpotential, and current density and the efficiency factor were calculated quantitatively. The models can be used to give accurate simulations for the polarisations of methanol fuel cell.

  4. (Non) formation of methanol by direct hydrogenation of formate on copper catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yong; Mims, Charles A.; Disselkamp, Robert S.; Kwak, Ja Hun; Peden, Charles HF; Campbell, C. T.

    2010-10-14

    We have attempted to hydrogenate adsorbed formate species on copper catalysts to probe the importance of this postulated mechanistic step in methanol synthesis. Surface formate coverages up to 0.25 were produced at temperatures between 413K and 453K on supported (Cu/SiO2) copper and unsupported copper catalysts. The adlayers were produced by various methods including (1) steady state catalytic conditions in CO2-H2 (3:1, 6 bar) atmospheres, and (2) by exposure of the catalysts to formic acid. As reported in earlier work, the catalytic surface at steady state contains bidentate formate species with coverages up to saturation levels of ~ 0.25 at the low temperatures of this study. The reactivity of these formate adlayers was investigated at relevant reaction temperatures in atmospheres containing up to 6 bar H2 partial pressure by simultaneous mass spectrometry (MS) and infrared (IR) spectroscopy measurements. The yield of methanol during the attempted hydrogenation (“titration”) of these adlayers was insignificant (<0.2 mol % of the formate adlayer) even in dry hydrogen partial pressures up to 6 bar. Hydrogen titration of formate species produced from formic acid also failed to produce significant quantities of methanol, and attempted titration in gases consisting of CO-hydrogen mixtures or dry CO2 were also unproductive. The formate decomposition kinetics, measured by IR, were also unaffected by these changes in the gas composition. Similar experiments on unsupported copper also failed to show any methanol. From these results, we conclude that methanol synthesis on copper cannot result from the direct hydrogenation of (bidentate) formate species in simple steps involving adsorbed H species alone. Furthermore, experiments performed on both supported (Cu/SiO2) and unsupported copper catalysts gave similar results implying that the methanol synthesis reaction mechanism only involves metal surface chemistry. Pre-exposure of the bidentate formate adlayer to oxidation

  5. SPEEK/epoxy resin composite membranes in situ polymerization for direct methanol fell cell usages

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Tiezhu; Zhao, Chengji; Zhong, Shuangling; Zhang, Gang; Shao, Ke; Zhang, Haiqiu; Wang, Jing; Na, Hui [Alan G. MacDiarmid Institute, College of Chemistry, Jilin University, Qianwei Road 2699, Changchun 130012 (China)

    2007-03-20

    Sulfonated poly(ether ether ketone) (SPEEK)/4,4'-diglycidyl(3,3',5,5'-tetramethylbiphenyl) epoxy resin (TMBP) composite membranes in situ polymerization were prepared for the purpose of improving the methanol resistance and mechanical properties of SPEEK membranes with high ion-exchange capacities (IEC) for the usage in the direct methanol fuel cells (DMFCs). The effects of introduction of TMBP content on the properties of the composite membranes were investigated in detail. The composite membranes have good mechanical, thermal properties, lower swelling ratio, lower water diffusion coefficient (0.87 x 10{sup -5} cm{sup 2} s{sup -1} at 80 C) and better methanol resistance (5.26 x 10{sup -7} cm{sup 2} s{sup -1} at 25 C) than SPEEK membranes. The methanol diffusion coefficients of the composite membranes are much lower than that of SPEEK membrane (17.5 x 10{sup -7} cm{sup 2} s{sup -1} at 25 C). Higher selectivity was been found for the composite membranes in comparison with SPEEK. Therefore, the SPEEK/TMBP composite membranes show a good potential in DMFCs usages. (author)

  6. Nanostructured Carbon Materials as Supports in the Preparation of Direct Methanol Fuel Cell Electrocatalysts

    Directory of Open Access Journals (Sweden)

    María Jesús Lázaro

    2013-08-01

    Full Text Available Different advanced nanostructured carbon materials, such as carbon nanocoils, carbon nanofibers, graphitized ordered mesoporous carbons and carbon xerogels, presenting interesting features such as high electrical conductivity and extensively developed porous structure were synthesized and used as supports in the preparation of electrocatalysts for direct methanol fuel cells (DMFCs. The main advantage of these supports is that their physical properties and surface chemistry can be tailored to adapt the carbonaceous material to the catalytic requirements. Moreover, all of them present a highly mesoporous structure, diminishing diffusion problems, and both graphitic character and surface area can be conveniently modified. In the present work, the influence of the particular features of each material on the catalytic activity and stability was analyzed. Results have been compared with those obtained for commercial catalysts supported on Vulcan XC-72R, Pt/C and PtRu/C (ETEK. Both a highly ordered graphitic and mesopore-enriched structure of these advanced nanostructured materials resulted in an improved electrochemical performance in comparison to the commercial catalysts assayed, both towards CO and alcohol oxidation.

  7. Highly Durable Direct Methanol Fuel Cell with Double-Layered Catalyst Cathode

    Directory of Open Access Journals (Sweden)

    Jing Liu

    2015-01-01

    Full Text Available Polymer electrolyte membrane (PEM is one of the key components in direct methanol fuel cells. However, the PEM usually gets attacked by reactive oxygen species during the operation period, resulting in the loss of membrane integrity and formation of defects. Herein, a double-layered catalyst cathode electrode consisting of Pt/CeO2-C as inner catalyst and Pt/C as outer catalyst is fabricated to extend the lifetime and minimize the performance loss of DMFC. Although the maximum power density of membrane electrode assembly (MEA with catalyst cathode is slightly lower than that of the traditional one, its durability is significantly improved. No obvious degradation is evident in the MEA with double-layered catalyst cathode within durability testing. These results indicated that Pt/CeO2-C as inner cathode catalyst layer greatly improved the stability of MEA. The significant reason for the improved stability of MEA is the ability of CeO2 to act as free-radical scavengers.

  8. A Review on the Fabrication of Electrospun Polymer Electrolyte Membrane for Direct Methanol Fuel Cell

    Directory of Open Access Journals (Sweden)

    Hazlina Junoh

    2015-01-01

    Full Text Available Proton exchange membrane (PEM is an electrolyte which behaves as important indicator for fuel cell’s performance. Research and development (R&D on fabrication of desirable PEM have burgeoned year by year, especially for direct methanol fuel cell (DMFC. However, most of the R&Ds only focus on the parent polymer electrolyte rather than polymer inorganic composites. This might be due to the difficulties faced in producing good dispersion of inorganic filler within the polymer matrix, which would consequently reduce the DMFC’s performance. Electrospinning is a promising technique to cater for this arising problem owing to its more widespread dispersion of inorganic filler within the polymer matrix, which can reduce the size of the filler up to nanoscale. There has been a huge development on fabricating electrolyte nanocomposite membrane, regardless of the effect of electrospun nanocomposite membrane on the fuel cell’s performance. In this present paper, issues regarding the R&D on electrospun sulfonated poly (ether ether ketone (SPEEK/inorganic nanocomposite fiber are addressed.

  9. Characterization of a direct methanol fuel cell using Hilbert curve fractal current collectors

    Energy Technology Data Exchange (ETDEWEB)

    Kuan, Yean-Der [Department of Refrigeration, Air-Conditioning and Energy Engineering, National Chun-Yi University of Technology, NO 35, Lane 215, Section 1, Chung-Shan Road, Taiping City, 411 Taichung County (China); Chang, Jing-Yi [Department of Mechanical and Electro-Mechanical Engineering, Tamkang University, Tamsui, 251 Taipei County (China); Lee, Shi-Min [Department of Aerospace Engineering, Tamkang University, Tamsui, 251 Taipei County (China); Lee, Shah-Rong [Department of Mechanical Engineering, Technology and Science Institute of Northern Taiwan, Peitou, 112 Taipei (China)

    2009-02-01

    The current collector or bi-polar plate is a key component in direct methanol fuel cells (DMFCs). Current collector geometric designs have significant influence on cell performance. This paper presents a continuous type fractal geometry using the Hilbert curve applied to current collector design in a direct methanol fuel cell. The Hilbert curve fractal geometry current collector is named HFCC (Hilbert curve fractal current collector). This research designs the current collector using a first, second and third order open carved HFCC shape. The cell performances of the different current collector geometries were measured and compared. Two important factors, the free open ratio and total perimeter length of the open carved design are discussed. The results show that both the larger free open ratio and longer carved open perimeter length present higher performance. (author)

  10. Characterization of a direct methanol fuel cell using Hilbert curve fractal current collectors

    Science.gov (United States)

    Kuan, Yean-Der; Chang, Jing-Yi; Lee, Shi-Min; Lee, Shah-Rong

    The current collector or bi-polar plate is a key component in direct methanol fuel cells (DMFCs). Current collector geometric designs have significant influence on cell performance. This paper presents a continuous type fractal geometry using the Hilbert curve applied to current collector design in a direct methanol fuel cell. The Hilbert curve fractal geometry current collector is named HFCC (Hilbert curve fractal current collector). This research designs the current collector using a first, second and third order open carved HFCC shape. The cell performances of the different current collector geometries were measured and compared. Two important factors, the free open ratio and total perimeter length of the open carved design are discussed. The results show that both the larger free open ratio and longer carved open perimeter length present higher performance.

  11. Two dimensional simulation of direct methanol fuel cell : a new (embedded) type of current collectors

    OpenAIRE

    Kulikovsky, A. A.; Divisek, J.; Kornyshev, Yu. M.

    2000-01-01

    A two-dimensional numerical model of the direct methanol fuel cell with gas fuel is developed. Simulation of the cell with current collectors of conventional geometry reveal the formation of fuel-depleted, "shaded" regions in the cathode and anode catalyst layers. These regions are positioned in front of current collectors, farther from the gas channel windows. Another disadvantage of the conventional geometry is the concentration of electron current at the edges of current collectors. Based ...

  12. TiO2 Nanotube-Carbon (TNT-C) as Support for Pt-based Catalyst for High Methanol Oxidation Reaction in Direct Methanol Fuel Cell.

    Science.gov (United States)

    Abdullah, M; Kamarudin, S K; Shyuan, L K

    2016-12-01

    In this study, TiO2 nanotubes (TNTs) were synthesized via a hydrothermal method using highly concentrated NaOH solutions varying from 6 to 12 M at 180 °C for 48 h. The effects of the NaOH concentration and the TNT crystal structure on the performance for methanol oxidation were investigated to determine the best catalyst support for Pt-based catalysts. The results showed that TNTs produced with 10 M NaOH exhibited a length and a diameter of 550 and 70 nm, respectively; these TNTs showed the best nanotube structure and were further used as catalyst supports for a Pt-based catalyst in a direct methanol fuel cell. The synthesized TNT and Pt-based catalysts were analysed by FESEM, TEM, BET, EDX, XRD and FTIR. The electrochemical performance of the catalysts was investigated using cyclic voltammetry (CV) and chronoamperometric (CA) analysis to further understand the methanol oxidation in the direct methanol fuel cell (DMFC). Finally, the result proves that Pt-Ru/TNT-C catalyst shows high performance in methanol oxidation as the highest current density achieved at 3.3 mA/cm(2) (normalised by electrochemically active surface area) and high catalyst tolerance towards poisoning species was established.

  13. TiO2 Nanotube-Carbon (TNT-C) as Support for Pt-based Catalyst for High Methanol Oxidation Reaction in Direct Methanol Fuel Cell

    Science.gov (United States)

    Abdullah, M.; Kamarudin, S. K.; Shyuan, L. K.

    2016-12-01

    In this study, TiO2 nanotubes (TNTs) were synthesized via a hydrothermal method using highly concentrated NaOH solutions varying from 6 to 12 M at 180 °C for 48 h. The effects of the NaOH concentration and the TNT crystal structure on the performance for methanol oxidation were investigated to determine the best catalyst support for Pt-based catalysts. The results showed that TNTs produced with 10 M NaOH exhibited a length and a diameter of 550 and 70 nm, respectively; these TNTs showed the best nanotube structure and were further used as catalyst supports for a Pt-based catalyst in a direct methanol fuel cell. The synthesized TNT and Pt-based catalysts were analysed by FESEM, TEM, BET, EDX, XRD and FTIR. The electrochemical performance of the catalysts was investigated using cyclic voltammetry (CV) and chronoamperometric (CA) analysis to further understand the methanol oxidation in the direct methanol fuel cell (DMFC). Finally, the result proves that Pt-Ru/TNT-C catalyst shows high performance in methanol oxidation as the highest current density achieved at 3.3 mA/cm2 (normalised by electrochemically active surface area) and high catalyst tolerance towards poisoning species was established.

  14. New polymeric electrolyte membranes based on proton donor-proton acceptor properties for direct methanol fuel cells

    NARCIS (Netherlands)

    Manea, Carmen; Mulder, Marcel

    2002-01-01

    In order to reduce the high methanol permeability of membranes in a direct methanol fuel cell application new and better materials are still required. In this paper membranes made from polybenzimidazole/sulfonated polysulfone are given and compared with homopolymer membranes made from sulfonated pol

  15. Characterization of polymer blends of polyethersulfone/sulfonated polysulfone and polyethersulfone/sulfonated polyetheretherketone for direct methanol fuel cell applications

    NARCIS (Netherlands)

    Manea, Carmen; Mulder, Marcel

    2002-01-01

    Existing polymer electrolyte membranes (PEMs) applied for hydrogen fuel cells are frequently not suitable for direct methanol fuel cells due to the high methanol permeability. Therefore, new materials are required and in order to avoid laborious fuel cell experiments with a so-called membrane–electr

  16. Enrichment and detection of microorganisms involved in direct and indirect methanogenesis from methanol in an anaerobic thermophilic bioreactor

    NARCIS (Netherlands)

    Roest, de K.; Altinbas, M.; Paulo, P.L.; Heilig, H.G.H.J.; Akkermans, A.D.L.; Smidt, H.; Vos, de W.M.; Stams, A.J.M.

    2005-01-01

    To gain insight into the microorganisms involved in direct and indirect methane formation from methanol in a laboratory-scale thermophilic (55°C) methanogenic bioreactor, reactor sludge was disrupted and serial dilutions were incubated in specific growth media containing methanol and possible interm

  17. Development of cesium phosphotungstate salt and chitosan composite membrane for direct methanol fuel cells.

    Science.gov (United States)

    Xiao, Yanxin; Xiang, Yan; Xiu, Ruijie; Lu, Shanfu

    2013-10-15

    A novel composite membrane has been developed by doping cesium phosphotungstate salt (CsxH3-xPW12O40 (0≤x≤3), Csx-PTA) into chitosan (CTS/Csx-PTA) for application in direct methanol fuel cells (DMFCs). Uniform distribution of Csx-PTA nanoparticles has been achieved in the chitosan matrix. The proton conductivity of the composite membrane is significantly affected by the Csx-PTA content in the composite membrane as well as the Cs substitution in PTA. The highest proton conductivity for the CTS/Csx-PTA membranes was obtained with x=2 and Cs2-PTA content of 5 wt%. The value is 6×10(-3) S cm(-1) and 1.75×10(-2) S cm(-1) at 298 K and 353 K, respectively. The methanol permeability of CTS/Cs2-PTA membrane is about 5.6×10(-7), 90% lower than that of Nafion-212 membrane. The highest selectivity factor (φ) was obtained on CTS/Cs2-PTA-5 wt% composite membrane, 1.1×10(4)/Scm(-3)s. The present study indicates the promising potential of CTS/Csx-PTA composite membrane as alternative proton exchange membranes in direct methanol fuel cells.

  18. Numerical simulation of direct methanol fuel cells using lattice Boltzmann method

    Energy Technology Data Exchange (ETDEWEB)

    Delavar, Mojtaba Aghajani; Farhadi, Mousa; Sedighi, Kurosh [Faculty of Mechanical Engineering, Babol University of Technology, Babol, P.O. Box 484 (Iran)

    2010-09-15

    In this study Lattice Boltzmann Method (LBM) as an alternative of conventional computational fluid dynamics method is used to simulate Direct Methanol Fuel Cell (DMFC). A two dimensional lattice Boltzmann model with 9 velocities, D2Q9, is used to solve the problem. The computational domain includes all seven parts of DMFC: anode channel, catalyst and diffusion layers, membrane and cathode channel, catalyst and diffusion layers. The model has been used to predict the flow pattern and concentration fields of different species in both clear and porous channels to investigate cell performance. The results have been compared well with results in literature for flow in porous and clear channels and cell polarization curves of the DMFC at different flow speeds and feed methanol concentrations. (author)

  19. Towards a compact SU-8 micro-direct methanol fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, J.P.; Santander, J.; Cane, C.; Sabate, N. [Instituto de Microelectronica de Barcelona, IMB-CNM (CSIC), Campus UAB, 08193 Bellaterra, Barcelona (Spain); Senn, T.; Loergen, M.; Loechel, B. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Application Centre for Microengineering, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Hernandez-Fernandez, P. [Dpto. Quimica-Fisica Aplicada, Facultad de Ciencias, Universidad Autonoma de Madrid (UAM), C/Francisco Tomas y Valiente 7, 28049 Madrid (Spain); Rojas, S. [Instituto de Catalisis y Petroleoquimica (CSIC), C/Marie Curie 2, 28049 Madrid (Spain)

    2010-12-15

    This paper presents an all-polymer micro-direct methanol fuel cell (microDMFC) fabricated with SU-8 photoresist. The present development exploits the capability of SU-8 components to bond to each other by a hot-pressing process and obtain a compact device. The device is formed by a membrane electrode assembly (MEA) sandwiched between two current collectors. The MEA consists of a porous SU-8 membrane filled with a proton exchange polymer and covered by a thin layer of carbon-based electrodes with a low catalyst loading (1.0 mg cm{sup -2}). The current collectors consist of two metalized SU-8 plates provided with a grid of through-holes that allow delivering the reactants to the MEA by diffusion. Fuel cell characterization was performed by measuring the polarization curves under different methanol concentrations and temperatures. The components were first tested using an external casing. A maximum power density of 4.15 mW cm{sup -2} was measured with this assembly working with a 4 M methanol concentration and at a temperature of 40 C. The components were then bonded to obtain a compact micro-direct methanol fuel cell that yielded a power density of 0.65 mW cm{sup -2} under the same conditions. Despite this decrease in power density after bonding, the drastic reduction of the device dimensions resulted in an increase of more than 50 times the previous volumetric power density. The results obtained validate this novel approach to an all-polymer micro-fuel cell. (author)

  20. Water transport in the cathode channels of direct methanol fuel cells; Wasseraustrag aus den Kathodenkanaelen von Direkt-Methanol-Brennstoffzellen

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Alexander

    2011-10-26

    Mass transport phenomena are vital for the operating performance of direct methanol fuel cells. In particular, the discharge of liquid water from the cathode channels is crucial for the supply of oxygen to the cathode and thus for operational stability. Droplets of water in the pores of the the diffusion layer and the cathode channels may lower the power output and induce locally negative current densities as they considerably limit the oxygen supply. This work investigates the water discharge from the cathode channels using neutron radiography, synchrotron radiography and locally resolved current density measurements and it identifies ways of improving the operational stability. Neutron radiography is a measuring technique suitable for detecting the water distribution in fuels cells under operating conditions. Synchrotron radiography is a method complementary to neutron radiography, allowing a more detailed analysis of smaller areas. Special test cells adapted to both measuring methods are developed. Their electrode areas are radiographed either frontally or laterally. To enable locally resolved current density measurements, a printed circuit board with a segmented contact area is integrated into each of the test cells. The measuring technique used is based on compensated sensor resistors, which ensure a reactionless measurement. In addition, the temperature distribution and the pressure drop on the cathod side are recorded. In order to correlated the water distribution, the current density distribution and the pressure drop, neutron radiography and synchrotron radiography are both combined with locally resolved current density measurements. Furthermore, current density measurements are performed under constant laboratory conditions to study the variation of paramenters. A measurement with a stack is also performed. The experiments reveal fundamental interdependencies between different factors and the discharge of water. At a given air ratio, the geometry and the

  1. Direct Conversion of Methane to Methanol under Mild Conditions over Cu-Zeolites and beyond.

    Science.gov (United States)

    Tomkins, Patrick; Ranocchiari, Marco; van Bokhoven, Jeroen A

    2017-02-21

    In the recent years methane has become increasingly abundant. However, transportation costs are high and methane recovered as side product is often flared rather than valorized. The chemical utilization of methane is highly challenging and currently mainly based on the cost-intensive production of synthesis gas and its conversion. Alternative routes have been discovered in academia, though high temperatures are mostly required. However, the direct conversion of methane to methanol is an exception. It can already be carried out at comparably low temperatures. It is challenging that methanol is more prone to oxidation than methane, which makes high selectivities at moderate conversions difficult to reach. Decades of research for the direct reaction of methane and oxygen did not yield a satisfactory solution for the direct partial oxidation toward methanol. When changing the oxidant from oxygen to hydrogen peroxide, high selectivities can be reached at rather low conversions, but the cost of hydrogen peroxide is comparably high. However, major advancements in the field were introduced by converting methane to a more stable methanol precursor. Most notable is the conversion of methane to methyl bisulfate in the presence of a platinum catalyst. The reaction is carried out in 102% sulfuric acid using SO3 as the oxidant. This allows for oxidation of the platinum catalyst and prevents the in situ hydrolysis of methyl bisulfate toward the less stable methanol. With a slightly different motif, the stepped conversion of methane to methanol over copper-zeolites was developed a decade ago. The copper-zeolite is first activated in oxygen at 450 °C, and then cooled to 200 °C and reacts with methane in the absence of oxygen, thus protecting a methanol precursor from overoxidation. Subsequently methanol can be extracted with water. Several active copper-zeolites were found, and the active sites were identified and discussed. For a long time, the process was almost unchanged

  2. Relating Direct Methanol Fuel Cell Performance to Measurements in a Liquid Half Cell

    DEFF Research Database (Denmark)

    Pedersen, Christoffer Mølleskov; Tynelius, Oskar; Lund-Olesen, Torsten

    2015-01-01

    Direct methanol fuel cells (DMFC) could act as a replacement for batteries in low power electronics. For instance, micro—DMFC’s could be used to power hearing instruments[1]. The power output of a DMFC is limited by the sluggish kinetics of both the methanol oxidation reaction (MOR) on the anode......) in the presence of methanol. By comparing the two measurements, we make recommendations for performing liquid half-cell measurements under realistic conditions. [1] J.H. Hales, C. Kallesøe, T. Lund-Olesen, A.-C. Johansson, H.C. Fanøe, Y. Yu, et al., Micro fuel cells power the hearing aids of the future, Fuel...... allow further miniaturization or powering more advanced and more power hungry devices. The activity of fuel cell catalysts is often probed in the form of thin films in liquid half cells. However, it is challenging to mimic the conditions in an actual DMFC. On the other hand, it can also be problematic...

  3. TUNING OF SIZE AND SHAPE OF AU-PT NANOCATALYST FOR DIRECT METHANOL FUEL CELLS

    Energy Technology Data Exchange (ETDEWEB)

    Murph, S.

    2011-04-20

    In this paper, we report the precise control of the size, shape and surface morphology of Au-Pt nanocatalysts (cubes, blocks, octahedrons and dogbones) synthesized via a seed-mediated approach. Gold 'seeds' of different aspect ratios (1 to 4.2), grown by a silver-assisted approach, were used as templates for high-yield production of novel Au-Pt nanocatalysts at a low temperature (40 C). Characterization by electron microscopy (SEM, TEM, HRTEM), energy dispersive X-ray analysis (EDX), UV-Vis spectroscopy, zeta-potential (surface charge), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma mass spectrometry (ICP-MS) were used to better understand their physico-chemical properties, preferred reactivities and underlying nanoparticle growth mechanism. A rotating disk electrode was used to evaluate the Au-Pt nanocatalysts electrochemical performance in the oxygen reduction reaction (ORR) and the methanol oxidation reaction (MOR) of direct methanol fuel cells. The results indicate the Au-Pt dogbones are partially and in some cases completely unaffected by methanol poisoning during the evaluation of the ORR. The ORR performance of the octahedron particles in the absence of MeOH is superior to that of the Au-Pt dogbones and Pt-black, however its performance is affected by the presence of MeOH.

  4. Radiation-grafted membranes based on polyethylene for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Sherazi, Tauqir A. [Department of Chemistry, Government College University, Lahore 54000 (Pakistan); Institute for Chemical Process and Environmental Technology, National Research Council Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6 (Canada); Guiver, Michael D.; Kingston, David; Xue, Xinzhong [Institute for Chemical Process and Environmental Technology, National Research Council Canada, 1200 Montreal Road, Ottawa, ON K1A 0R6 (Canada); Ahmad, Shujaat [PIEAS/PINSTECH, P O Nilore, Islamabad 45650 (Pakistan); Kashmiri, M. Akram [Department of Chemistry, Government College University, Lahore 54000 (Pakistan); Board of Intermediate and Secondary Education, Lahore 54000 (Pakistan)

    2010-01-01

    Styrene was grafted onto ultrahigh molecular weight polyethylene powder (UHMWPE) by gamma irradiation using a {sup 60}Co source. Compression moulded films of selected pre-irradiated styrene-grafted ultrahigh molecular weight polyethylene (UHMWPE-g-PS) were post-sulfonated to the sulfonic acid derivative (UHMWPE-g-PSSA) for use as proton exchange membranes (PEMs). The sulfonation was confirmed by X-ray photoelectron spectroscopy (XPS). The melting and flow properties of UHMWPE and UHMWPE-g-PS are conducive to forming homogeneous pore-free membranes. Both the ion conductivity and methanol permeability coefficient increased with degree of grafting, but the grafted membranes showed comparable or higher ion conductivity and lower methanol permeability than Nafion {sup registered} 117 membrane. One UHMWPE-g-PS membrane was fabricated into a membrane-electrode assembly (MEA) and tested as a single cell direct methanol fuel cell (DMFC). Low membrane cost and acceptable fuel cell performance indicate that UHMWPE-g-PSSA membranes could offer an alternative approach to perfluorosulfonic acid-type membranes for DMFC. (author)

  5. Radiation-grafted membranes based on polyethylene for direct methanol fuel cells

    Science.gov (United States)

    Sherazi, Tauqir A.; Guiver, Michael D.; Kingston, David; Ahmad, Shujaat; Kashmiri, M. Akram; Xue, Xinzhong

    Styrene was grafted onto ultrahigh molecular weight polyethylene powder (UHMWPE) by gamma irradiation using a 60Co source. Compression moulded films of selected pre-irradiated styrene-grafted ultrahigh molecular weight polyethylene (UHMWPE-g-PS) were post-sulfonated to the sulfonic acid derivative (UHMWPE-g-PSSA) for use as proton exchange membranes (PEMs). The sulfonation was confirmed by X-ray photoelectron spectroscopy (XPS). The melting and flow properties of UHMWPE and UHMWPE-g-PS are conducive to forming homogeneous pore-free membranes. Both the ion conductivity and methanol permeability coefficient increased with degree of grafting, but the grafted membranes showed comparable or higher ion conductivity and lower methanol permeability than Nafion ® 117 membrane. One UHMWPE-g-PS membrane was fabricated into a membrane-electrode assembly (MEA) and tested as a single cell direct methanol fuel cell (DMFC). Low membrane cost and acceptable fuel cell performance indicate that UHMWPE-g-PSSA membranes could offer an alternative approach to perfluorosulfonic acid-type membranes for DMFC.

  6. The kinetic studies of direct methane oxidation to methanol in the plasma process

    Institute of Scientific and Technical Information of China (English)

    INDARTO Antonius; CHOI Jae-Wook; LEE Hwaung; SONG Hyung Keun

    2008-01-01

    The research outlined here includes a study of methanol production from direct methane conversion by means of thermal and plasma method. The kinetic study, derived from thermal-based approach, was carried out to investigate thoroughly the possible intermediate species likely to be presented in the process. A set of plasma experiments was undertaken by using dielectric barrier discharge (DBD), classified as non-thermal plasma, done at atmospheric pressure and room temperature. Plasma proc-ess yields more methanol than thermal process at the same methane conversion rates and methane to oxygen feed ratios. Oxidation reaction of thermal process resulted CO and CO2 as the most dominant products and the selectivity reached 19% and 68%, respectively. Moreover, more CO and less CO2 were produced in plasma process than in thermal process. The selectivity of CO and CO2 by plasma was 47% and 20%, respectively. Ethane (C2H6) was detected as the only higher hydrocarbon with a signifi-cant concentration. The concentration of ethane reached 9% of the total products in plasma process and 17% in thermal process. The maximum selectivity of methanol, the target material of this research, was 12% obtained by plasma method and less than 5% by thermal process. In some certain points, the kinetic model closely matched with the experimental results.

  7. A spontaneous and passive waste-management device (PWMD) for a micro direct methanol fuel cell

    Science.gov (United States)

    Chuang, Yun-Ju; Chieng, Ching-Chang; Pan, Chin; Luo, Shih-Jin; Tseng, Fan-Gang

    2007-05-01

    This paper introduces a passive waste-management device (PWMD) for a micro direct methanol fuel cell to exhale CO2 gas and to gather and transport water and methanol residue during operation. It passively employs condensation, temperature gradient, surface tension gradient and droplet coalescence to accumulate liquid, separate liquid and gas, and transport droplets without the need of external power. CO2 gas can be breathed out through hydrophobic micro holes with the assistance of buoyancy force while water/methanol vapor is condensing into droplets, coalescing with smaller droplets and is transported toward a cooler and more hydrophilic waste tank through wettability gradient. The wettability gradient is prepared by diffusion-controlled silanization with a gradient from 117° to 28° and is radial toward the outer boundary, which can drive droplets down to 1 µl with a speed of up to 20 mm s-1. With the assistance of coalescence along with the wettability gradient, the condensed water droplets can reach a double speed of 40 mm s-1. The maximum water removal rate of the PWMD can approach 6.134 µl s-1 cm-2, which is at least one order of magnitude higher than the demand of a standard µDMFC with power generation ability of 100 mW cm-2.

  8. Preparation and characterization of the PVDF-based composite membrane for direct methanol fuel cells

    Directory of Open Access Journals (Sweden)

    Qian Liu, Laizhou Song, Zhihui Zhang, Xiaowei Liu

    2010-07-01

    Full Text Available The polyvinylidene fluoride-sulfonated polystyrene composite membrane with proton exchange performance, denoted as PVDF-SPS, was prepared using a thermally induced polymerization technique. The thermal stability of the PVDF-SPS composite membrane was investigated using thermogravimetric (TG analysis. The complex formation of the composite membrane was ascertained by Fourier transform infrared spectroscopy (FTIR. The surface compositions of the PVDF-SPS membrane were analyzed using X-ray photoelectron spectroscopy (XPS. The morphology of the composite membrane was characterized by environmental scanning electron microscopy (ESEM. The proton conductivity of the PVDF-SPS membrane was measured using impedance spectroscopy in the hydrated condition. The PVDF-SPS membrane has a stronger hydrophilic character than the pristine PVDF membrane and the polyvinylidene fluoride-polystyrene composite membrane (PVDF-PS, which is caused by the incorporation of sulfonic acid groups. The proton conductivity and the methanol permeability of the PVDF-SPS membrane measured at 298 K are 29.3 mS.cm-1 and 8.6×10-8 cm2.s-1, respectively. Although PVDF-SPS composite membrane possesses the lower oxidative stability than Nafion-117 membrane, the composite membrane displays lower methanol permeability than the Nafion-117 membrane, and the selectivity (the ratio of proton conductivity and methanol permeability of the composite membrane is almost 20 times than that of Nafion-117.

  9. Development of Low-Intermediate Temperature Fuel Cells for Direct Conversion of Methane to Methanol Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Torabi, Alireza; Barton, Joseph D.; Willman, Carl; Ghezel-Ayagh, Hossein; Li, Na; Poozhikunnath, Abhinav; Maric, Radenka; Marina, Olga A.

    2017-09-26

    The objective of this project is development of a durable, low-cost, and high performance Low Temperature Solid Oxide Fuel Cell (LT-SOFC) for direct conversion of methane to methanol and other liquids, characterized by: a) operating temperature < 500oC, b) current density of > 100 mA/cm2 in liquid hydrocarbon production mode, c) continuous operation of > 100 h, d) cell area >100 cm2, e) cell cost per rate of product output < 100,000/bpd, f) process intensity of > 0.1 bpd/ft3, g) product yield and carbon efficiency > 50%, and h) volumetric output per cell > 30 L/day.

  10. PREPARATION AND PROPERTIES OF SPAES-TiO_2 HYBRID MEMBRANES FOR DIRECT METHANOL FUEL CELL

    Institute of Scientific and Technical Information of China (English)

    刘惠玲

    2009-01-01

    Sulfonated poly(arylene ether sulfone)(SPAES) copolymer with degree of sulfonation of 1.0 was synthesized and characterized.A series of SPAES-TiO_2 hybrid membranes with various contents of nano-sized TiO_2 particles were prepared and characterized through sol-gel reactions.Scanning electron microscopy(SEM) images indicated the TiO_2 particles were well dispersed within polymer matrix.These composite membranes were evaluated for proton exchange membranes(PEMs) in direct methanol fuel cell(DMFC).These mem...

  11. Graphene-derived Fe/Co-N-C catalyst in direct methanol fuel cells: Effects of the methanol concentration and ionomer content on cell performance

    Science.gov (United States)

    Park, Jong Cheol; Choi, Chang Hyuck

    2017-08-01

    Non-precious metal catalysts (typically Fe(Co)-N-C catalysts) have been widely investigated for use as cost-effective cathode materials in low temperature fuel cells. Despite the high oxygen reduction activity and methanol-tolerance of graphene-based Fe(Co)-N-C catalysts in an acidic medium, their use in direct methanol fuel cells (DMFCs) has not yet been successfully implemented, and only a few studies have investigated this topic. Herein, we synthesized a nano-sized graphene-derived Fe/Co-N-C catalyst by physical ball-milling and a subsequent chemical modification of the graphene oxide. Twelve membrane-electrode-assemblies are fabricated with various cathode compositions to determine the effects of the methanol concentration, ionomer (i.e. Nafion) content, and catalyst loading on the DMFC performance. The results show that a graphene-based catalyst is capable of tolerating a highly-concentrated methanol feed up to 10.0 M. The optimized electrode composition has an ionomer content and catalyst loading of 66.7 wt% and 5.0 mg cm-2, respectively. The highest maximum power density is ca. 32 mW cm-2 with a relatively low PtRu content (2 mgPtRu cm-2). This study overcomes the drawbacks of conventional graphene-based electrodes using a nano-sized graphene-based catalyst and further shows the feasibility of their potential applications in DMFC systems.

  12. High Performance and Cost-Effective Direct Methanol Fuel Cells: Fe-N-C Methanol-Tolerant Oxygen Reduction Reaction Catalysts.

    Science.gov (United States)

    Sebastián, David; Serov, Alexey; Artyushkova, Kateryna; Gordon, Jonathan; Atanassov, Plamen; Aricò, Antonino S; Baglio, Vincenzo

    2016-08-09

    Direct methanol fuel cells (DMFCs) offer great advantages for the supply of power with high efficiency and large energy density. The search for a cost-effective, active, stable and methanol-tolerant catalyst for the oxygen reduction reaction (ORR) is still a great challenge. In this work, platinum group metal-free (PGM-free) catalysts based on Fe-N-C are investigated in acidic medium. Post-treatment of the catalyst improves the ORR activity compared with previously published PGM-free formulations and shows an excellent tolerance to the presence of methanol. The feasibility for application in DMFC under a wide range of operating conditions is demonstrated, with a maximum power density of approximately 50 mW cm(-2) and a negligible methanol crossover effect on the performance. A review of the most recent PGM-free cathode formulations for DMFC indicates that this formulation leads to the highest performance at a low membrane-electrode assembly (MEA) cost. Moreover, a 100 h durability test in DMFC shows suitable applicability, with a similar performance-time behavior compared to common MEAs based on Pt cathodes.

  13. Sulfonated polystyrene-type plasma-polymerized membranes for miniature direct methanol fuel cells

    Science.gov (United States)

    Roualdes, Stéphanie; Topala, Ionut; Mahdjoub, Habiba; Rouessac, Vincent; Sistat, Philippe; Durand, Jean

    Sulfonated polystyrene-type membranes were synthesized by plasma polymerization of a mixture of styrene and trifluoromethane sulfonic acid monomers in a low-frequency after-glow discharge plasma reactor. Such a deposition process enables the preservation of the monomers structure, which was confirmed by mass spectrometry analysis. The synthesized plasma-polymerized membranes are dense and uniform with a few microns thickness. Their structure determined by Fourier-transform infra-red spectroscopy and X-ray photoelectron spectroscopy is very rich in sulfonic acid groups (up to 5%) and stable up to 120 °C. Even if their intrinsic proton conductivity is low (10 -1 mS cm -1), directly related to their disorganized and highly cross-linked structure, plasma-polymerized membranes present a proton conduction ability similar to Nafion ® because of their low thickness. Due to their highly cross-linked structure, these membranes enable a reduction of the methanol crossover in a factor 10 by comparison with Nafion ®. Thus, the integration of plasma-polymerized films in miniaturized direct methanol fuel cells as proton-exchange membranes seems promising.

  14. Layer-by-layer self-assembly of composite polyelectrolyte-Nafion membranes for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, S.P.; Liu, Z.; Tian, Z.Q. [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2006-04-18

    A novel composite polyelectrolyte/Nafion membrane is demonstrated that is fabricated using the layer-by-layer self-assembly of oppositely charged polyelectrolytes. A direct methanol fuel cell based on such a membrane is shown to achieve a significant reduction in methanol crossover and an increase in power density of 42 %, in comparison to that which uses a pristine Nafion membrane. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  15. Preparation and influence of performance of anodic catalysts for direct methanol fuel cell

    Institute of Scientific and Technical Information of China (English)

    WANG Zhenbo; YIN Geping; SHI Pengfei

    2007-01-01

    This research aims at increasing the utilization of platinum-ruthenium alloy (Pt-Ru) catalysts and thus lowering the catalyst loading in anodes for methanol electrooxidation.The direct methanol fuel cell's (DMFC) anodic catalysts,Pt-Ru/C,were prepared by chemical reduction with a reducing agent added in two kinds of solutions under different circumstances.The reducing agent was added in hot solution with the protection of inert gases or just air,and in cold solution with inert gases.The catalysts were treated at different temperatures.Their performance was tested by cyclic voltammetry and potentiostatic polarization by utilizing their inherent powder microelectrode in 0.5 mol/L CH3OH and 0.5 mol/L H2SO4 solution.The structures and micro-surface images ofthe catalysts were determined and observed by X-ray diffraction and transmission electron microscopy,respectively.The catalyst prepared in inert gases showed a better catalytic performance for methanol electrooxidation than that prepared in air.It resulted in a more homogeneous distribution of the Pt-Ru alloy in carbon.Its size is small,only about 4.5 nm.The catalytic performance is affected by the order of the reducing agent added.The performance of the catalyst prepared by adding the reductant at constant temperature of the solution is better than that prepared by adding it in the solution at 0℃ and then heating it up to the reducing temperature.The structure of the catalyst was modified,and there was an increase in the conversion of ruthenium into the alloyed state and an increase in particle size with the ascension of heat treatment temperature.In addition,the stability of the catalyst was improved after heat treatment.

  16. PREPARATION AND PROPERTIES OF SPAES-TiO_2 HYBRID MEMBRANES FOR DIRECT METHANOL FUEL CELL

    Institute of Scientific and Technical Information of China (English)

    Ni Zhang; Hui-ling Liu; Jun-jing Li; Zhi Xia

    2009-01-01

    Sulfonated poly(arylene ether sulfone) (SPAES) copolymer with degree of sulfonation of 1.0 was synthesized and characterized. A series of SPAES-TiO_2 hybrid membranes with various contents of nano-sized TiO_2 particles were prepared and characterized through sol-gel reactions. Scanning electron microscopy (SEM) images indicated the TiO_2 particles were well dispersed within polymer matrix. These composite membranes were evaluated for proton exchange membranes (PEMs) in direct methanol fuel cell (DMFC). These membranes showed good thermal stability and mechanical properties. It was found that the water uptake of these membranes increased with the increase of the TiO_2 contents in the hybrid membranes. Meanwhile, the introduction of inorganic particles increased the proton conductivity and reduced the methanol permeability. The proton conductivities (0.118-0.162 S/cm) of SPAES-TiO_2 hybrid membranes with 8% TiO_2 particles are much higher than those of Nation 117 membrane (0.095-0.117 S/cm) and pure SPAES membrane (0.100-0.124 S/cm) with degree of sulfonation of 1.0 at all temperatures (25-100℃). Especially, the methanol diffusion coefficient (8.4×10~(-7) cm~2/s) of SPAES-TiO_2 hybrid membranes with 8% TiO_2 is much lower than that of Nation 117 membrane (2.1 ×10~(-6) cm~2/s). SPAES-TiO_2 hybrid membranes were therefore proposed as candidates of material for PEM in DMFC.

  17. Mass transport of direct methanol fuel cell species in sulfonated poly(ether ether ketone) membranes

    Energy Technology Data Exchange (ETDEWEB)

    Silva, V.S.; Boaventura, M.; Mendes, A.M.; Madeira, L.M. [LEPAE, Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Ruffmann, B.; Vetter, S.; Nunes, S.P. [GKSS Research Centre, Max-Planck Str., 21502 Geesthacht (Germany)

    2006-05-05

    Homogeneous membranes based on sulfonated poly(ether ether ketone) (sPEEK) with different sulfonation degrees (SD) were prepared and characterized. In order to perform a critical analysis of the SD effect on the polymer barrier and mass transport properties towards direct methanol fuel cell species, proton conductivity, water/methanol pervaporation and nitrogen/oxygen/carbon dioxide pressure rise method experiments are proposed. This procedure allows the evaluation of the individual permeability coefficients in hydrated sPEEK membranes with different sulfonation degrees. Nafion{sup (R)} 112 was used as reference material. DMFC tests were also performed at 50{sup o}C. It was observed that the proton conductivity and the permeability towards water, methanol, oxygen and carbon dioxide increase with the sPEEK sulfonation degree. In contrast, the SD seems to not affect the nitrogen permeability coefficient. In terms of selectivity, it was observed that the carbon dioxide/oxygen selectivity increases with the sPEEK SD. In contrast, the nitrogen/oxygen selectivity decreases. In terms of barrier properties for preventing the DMFC reactants loss, the polymer electrolyte membrane based on the sulfonated poly(ether ether ketone) with SD lower or equal to 71%, although having slightly lower proton conductivity, presented much better characteristics for fuel cell applications compared with the well known Nafion{sup (R)} 112. In terms of the DMFC tests of the studied membranes at low temperature, the sPEEK membrane with SD=71% showed to have similar performance, or even better, as that of Nafion{sup (R)} 112. However, the highest DMFC overall efficiency was achieved using sPEEK membrane with SD=52%. (author)

  18. Carbon Nanotubes Supported Pt-Ru-Ni as Methanol Electro-Oxidation Catalyst for Direct Methanol Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    Fei Ye; Shengzhou Chen; Xinfa Dong; Weiming Lin

    2007-01-01

    Carbon nanotubes (CNTs) supported Pt-Ru and Pt-Ru-Ni catalysts were prepared by chemical reduction of metal precursors with sodium borohydride at room temperature. The crystallographic properties and composition of the catalysts were characterized by X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis, and the catalytic activity and stability for methanol electro-oxidation were measured by electrochemical impedance spectroscopy (EIS), linear sweep voltammetries (LSV), and chronoamperometry (CA). The results show that the catalysts exhibit face-centered cubic (fcc) structure.The particle size of Pt-Ru-Ni/CNTs catalyst is about 4.8 nm. The catalytic activity and stability of the Pt-Ru-Ni/CNTs catalyst are higher than those of Pt-Ru/CNTs catalyst.

  19. Direct QM/MM excited-state dynamics of retinal protonated Schiff base in isolation and methanol solution.

    Science.gov (United States)

    Punwong, Chutintorn; Owens, Jane; Martínez, Todd J

    2015-01-22

    We use the full multiple spawning (FMS) dynamics approach with a hybrid quantum mechanics/molecular mechanics (QM/MM) reparameterized semiempirical method to investigate the excited-state dynamics of retinal protonated Schiff base (RPSB) in isolation, in neat methanol solution, and in methanol solution with a Cl(-) counterion. The excited-state lifetime is dramatically affected by MeOH solvent, which slows down the photoisomerization by an order of magnitude. We show that this is due to charge migration in the RPSB chromophore and the concomitant solvent friction in polar media. Simulation results are compared to experiments where available, with good agreement for excited-state lifetimes, bond selectivity of isomerization, and the time/energy-resolved fluorescence spectrum. We find that the inclusion of a Cl(-) counterion in the simulations has little effect on lifetimes, mechanism, or bond selectivity. In contrast to previous studies limited to RPSB and a surrounding counterion, we find that the placement of the counterion has little effect on bond selectivity. This suggests that dielectric screening can spoil the effect of a counterion in directing excited-state reactivity.

  20. A direct methanol fuel cell system to power a humanoid robot

    Energy Technology Data Exchange (ETDEWEB)

    Joh, Han-Ik [Center for Fuel Cell Research, Korea Institute of Science and Technology (KIST), P.O. Box 131, Cheongyang, Seoul 130-650 (Korea); School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, San 56-1, Shillim-dong, Kwanak-ku, Seoul 151-744 (Korea); Ha, Tae Jung; Hwang, Sang Youp; Kim, Jong-Ho; Chae, Seung-Hoon; Cho, Jae Hyung; Prabhuram, Joghee; Kim, Soo-Kil; Lim, Tae-Hoon; Ha, Heung Yong [Center for Fuel Cell Research, Korea Institute of Science and Technology (KIST), P.O. Box 131, Cheongyang, Seoul 130-650 (Korea); Cho, Baek-Kyu; Oh, Jun-Ho [HUBO Laboratory, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea); Moon, Sang Heup [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, San 56-1, Shillim-dong, Kwanak-ku, Seoul 151-744 (Korea)

    2010-01-01

    In this study, a direct methanol fuel cell (DMFC) system, which is the first of its kind, has been developed to power a humanoid robot. The DMFC system consists of a stack, a balance of plant (BOP), a power management unit (PMU), and a back-up battery. The stack has 42 unit cells and is able to produce about 400 W at 19.3 V. The robot is 125 cm tall, weighs 56 kg, and consumes 210 W during normal operation. The robot is integrated with the DMFC system that powers the robot in a stable manner for more than 2 h. The power consumption by the robot during various motions is studied, and load sharing between the fuel cell and the back-up battery is also observed. The loss of methanol feed due to crossover and evaporation amounts to 32.0% and the efficiency of the DMFC system in terms of net electric power is 22.0%. (author)

  1. Stable operation of air-blowing direct methanol fuel cells with high performance

    Science.gov (United States)

    Park, Jun-Young; Lee, Jin-Hwa; Kim, Jirae; Han, Sangil; Song, Inseob

    A membrane electrode assembly (MEA) that is a combination of a catalyst-coated membrane (CCM) for the anode and a catalyst-coated substrate (CCS) for the cathode is studied under air-blower conditions for direct methanol fuel cells (DMFCs). Compared with MEAs prepared by only the CCS method, the performance of DMFC MEAs employing the combination method is significantly improved by 30% with less methanol crossover. This feature can be attributed to an enhanced electrode|membrane interface in the anode side and significantly higher catalyst efficiency. Furthermore, DMFC MEAs designed by the combination method retain high power density without any degradation, while the CCM-type cell shows a downward tendency in electrochemical performance under air-blower conditions. This may be due to MEAs with CCM have a much more difficult structure of catalytic active sites in the cathode to eliminate the water produced by electrochemical reaction. In addition, DMFCs produced via combination methods exhibit a lower water crossover flux than CCS alternatives, due to the comparatively dense structure of the CCM anode. Hence, DMFCs with a combination MEA structure demonstrate the feasibility of a small fuel cell system employing the low noise of a fan, instead of a noisy and large capacity air pump, for portable electronic devices.

  2. Microwave synthesis of polymer-embedded Pt-Ru catalyst for direct methanol fuel cell.

    Science.gov (United States)

    Bensebaa, Farid; Farah, Abdiaziz A; Wang, Dashan; Bock, Christina; Du, Xiaomei; Kung, Judy; Le Page, Yvon

    2005-08-18

    Platinum-ruthenium nanoparticles stabilized within a conductive polymer matrix are prepared using microwave heating. Polypyrrole di(2-ethylhexyl) sulfosuccinate, or PPyDEHS, has been chosen for its known electrical conductivity, thermal stability, and solubility in polar organic solvents. A scalable and quick two-step process is proposed to fabricate alloyed nanoparticles dispersed in PPyDEHS. First a mixture of PPyDEHS and metallic precursors is heated in a microwave under reflux conditions. Then the nanoparticles are extracted by centrifugation. Physical characterization by TEM shows that crystalline and monodisperse alloyed nanoparticles with an average size of 2.8 nm are obtained. Diffraction data show that crystallite size is around 2.0 nm. Methanol electro-oxidation data allow us to propose these novel materials as potential candidates for direct methanol fuel cells (DMFC) application. The observed decrease in sulfur content in the polymer upon incorporation of PtRu nanoparticles may have adversely affected the measured catalytic activity by decreasing the conductivity of PPyDEHS. Higher concentration of polymer leads to lower catalyst activity. Design and synthesis of novel conductive polymers is needed at this point to enhance the catalytic properties of these hybrid materials.

  3. BLEND MEMBRANES FOR DIRECT METHANOL AND PROTON EXCHANGE MEMBRANE FUEL CELLS

    Institute of Scientific and Technical Information of China (English)

    Perurnal Bhavani; Dharmalingam Sangeetha

    2012-01-01

    Sulphonated polystyrene ethylene butylene polystyrene (SPSEBS) prepared with 35% sulphonation was found to be highly elastic and enlarged up to 300%-400% of its initial length.It absorbed over 110% of water by weight.A major drawback of this membrane is its poor mechanical properties which are not adequate for use as polymer electrolytes in fuel cells.To overcome this,SPSEBS was blended with poly(vinylidene fluoride) (PVDF),a hydrophobic polymer.The blend membranes showed better mechanical properties than the base polymer.The effect of PVDF content on water uptake,ion exchange capacity and proton conductivity of the blend membranes was investigated.This paper presents the results of recent studies applied to develop an optimized in-house membrane electrode assembly (MEA) preparation technique combining catalyst ink spraying and assembly hot pressing.Easy steps were chosen in this preparation technique in order to simplify the method,aiming at cost reduction.The open circuit voltage for the cell with SPSEBS is 0.980 V which is higher compared to that of the cell with Nafion 117 (0.790 V).From this study,it is concluded that a polymer electrolyte membrane suitable for proton exchange membrane fuel cell (PEMFC) and direct methanol fuel cell (DMFC) application can be obtained by blending SPSEBS and PVDF in appropriate proportions.The methanol permeability and selectivity showed a strong influence on DMFC performance.

  4. Artificial Intelligence Techniques for the Estimation of Direct Methanol Fuel Cell Performance

    Science.gov (United States)

    Hasiloglu, Abdulsamet; Aras, Ömür; Bayramoglu, Mahmut

    2016-04-01

    Artificial neural networks and neuro-fuzzy inference systems are well known artificial intelligence techniques used for black-box modelling of complex systems. In this study, Feed-forward artificial neural networks (ANN) and adaptive neuro-fuzzy inference system (ANFIS) are used for modelling the performance of direct methanol fuel cell (DMFC). Current density (I), fuel cell temperature (T), methanol concentration (C), liquid flow-rate (q) and air flow-rate (Q) are selected as input variables to predict the cell voltage. Polarization curves are obtained for 35 different operating conditions according to a statistically designed experimental plan. In modelling study, various subsets of input variables and various types of membership function are considered. A feed -forward architecture with one hidden layer is used in ANN modelling. The optimum performance is obtained with the input set (I, T, C, q) using twelve hidden neurons and sigmoidal activation function. On the other hand, first order Sugeno inference system is applied in ANFIS modelling and the optimum performance is obtained with the input set (I, T, C, q) using sixteen fuzzy rules and triangular membership function. The test results show that ANN model estimates the polarization curve of DMFC more accurately than ANFIS model.

  5. The electrolyte challenge for a direct methanol-air polymer electrolyte fuel cell operating at temperatures up to 200 C

    Science.gov (United States)

    Savinell, Robert; Yeager, Ernest; Tryk, Donald; Landau, Uziel; Wainright, Jesse; Gervasio, Dominic; Cahan, Boris; Litt, Morton; Rogers, Charles; Scherson, Daniel

    1993-01-01

    Novel polymer electrolytes are being evaluated for use in a direct methanol-air fuel cell operating at temperatures in excess of 100 C. The evaluation includes tests of thermal stability, ionic conductivity, and vapor transport characteristics. The preliminary results obtained to date indicate that a high temperature polymer electrolyte fuel cell is feasible. For example, Nafion 117 when equilibrated with phosphoric acid has a conductivity of at least 0.4 Omega(exp -1)cm(exp -1) at temperatures up to 200 C in the presence of 400 torr of water vapor and methanol vapor cross over equivalent to 1 mA/cm(exp 2) under a one atmosphere methanol pressure differential at 135 C. Novel polymers are also showing similar encouraging results. The flexibility to modify and optimize the properties by custom synthesis of these novel polymers presents an exciting opportunity to develop an efficient and compact methanol fuel cell.

  6. A Novel Sulfided Mo/C Catalyst for Direct Vapor Phase Carbonylation of Methanol at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    Feng Peng

    2003-01-01

    The direct carbonylation of methanol, without any halide in the feed as a promoter, ispresented. A series of Mo catalysts supported on activated carbon, γ-Al2O3 and SiO2 were prepared.The results show that the support greatly affects the Mo catalyst in the direct vapor-phase carbonylationof methanol, and activated carbon is the best supports of the investigated supports. In addition, therelationships between adsorptions of NH3 and CO and carbonylation of methanol were investigated. A novelsulfided Mo/C catalyst had high activity and selectivity for the vapor phase carbonylation of methanol tomethyl acetate without the addition ofa CH3I promoter to the feed. The reaction conditions were optimizedat a reaction temperature of 573 K, a methanol concentration of 23 mol% and a carbon monoxide spacevelocity of 3,000 L/(kg.h). Under these optimal conditions a methanol conversion of 50%, carbonylationselectivity of 80 mol%, and space-time yield of 8.0 mol/(kg.h) were obtained. The active phase of thisnovel sulfided Mo/C catalyst is the non-crystalline phase, and the active component is present as MoS2.5on the surface of the activated carbon.

  7. Temperature modeling and control of Direct Methanol Fuel Cell based on adaptive neural fuzzy technology

    Institute of Scientific and Technical Information of China (English)

    Qi Zhidong; Zhu Xinjian; Cao Guangyi

    2006-01-01

    Aiming at on-line controlling of Direct Methanol Fuel Cell (DMFC) stack, an adaptive neural fuzzy inference technology is adopted in the modeling and control of DMFC temperature system. In the modeling process, an Adaptive Neural Fuzzy Inference System (ANFIS) identification model of DMFC stack temperature is developed based on the input-output sampled data, which can avoid the internal complexity of DMFC stack. In the controlling process, with the network model trained well as the reference model of the DMFC control system, a novel fuzzy genetic algorithm is used to regulate the parameters and fuzzy rules of a neural fuzzy controller. In the simulation, compared with the nonlinear Proportional Integral Derivative (PID) and traditional fuzzy algorithm, the improved neural fuzzy controller designed in this paper gets better performance, as demonstrated by the simulation results.

  8. Micro direct methanol fuel cell with perforated silicon-plate integrated ionomer membrane

    DEFF Research Database (Denmark)

    Larsen, Jackie Vincent; Dalslet, Bjarke Thomas; Johansson, Anne-Charlotte Elisabeth Birgitta

    2014-01-01

    This article describes the fabrication and characterization of a silicon based micro direct methanol fuel cell using a Nafion ionomer membrane integrated into a perforated silicon plate. The focus of this work is to provide a platform for micro- and nanostructuring of a combined current collector...... at a perforation ratio of 40.3%. The presented fuel cells also show a high volumetric peak power density of 2 mW cm−3 in light of the small system volume of 480 μL, while being fully self contained and passively feed....... and catalytic electrode. AC impedance spectroscopy is utilized alongside IV characterization to determine the influence of the plate perforation geometries on the cell performance. It is found that higher ratios of perforation increases peak power density, with the highest achieved being 2.5 mW cm−2...

  9. A monolithic integrated micro direct methanol fuel cell based on sulfo functionalized porous silicon

    Science.gov (United States)

    Wang, M.; Lu, Y. X.; Liu, L. T.; Wang, X. H.

    2016-11-01

    In this paper, we demonstrate a monolithic integrated micro direct methanol fuel cell (μDMFC) for the first time. The monolithic integrated μDMFC combines proton exchange membrane (PEM) and Pt nanocatalysts, in which PEM is achieved by the functionalized porous silicon membrane and 3D Pt nanoflowers being synthesized in situ on it as catalysts. Sulfo groups functionalized porous silicon membrane serves as a PEM and a catalyst support simultaneously. The μDMFC prototype achieves an open circuit voltage of 0.3 V, a maximum power density of 5.5 mW/cm2. The monolithic integrated μDMFC offers several desirable features such as compatibility with micro fabrication techniques, an undeformable solid PEM and the convenience of assembly.

  10. SHAPE SELECTIVE NANO-CATALYSTS: TOWARD DIRECT METHANOL FUEL CELLS APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Murph, S.

    2010-06-16

    A series of bimetallic core-shell-alloy type Au-Pt nanomaterials with various morphologies, aspect ratios and compositions, were produced in a heterogenous epitaxial fashion. Gold nanoparticles with well-controlled particle size and shape, e.g. spheres, rods and cubes, were used as 'seeds' for platinum growth in the presence of a mild reducing agent, ascorbic acid and a cationic surfactant cethyltrimethyl ammonium bromide (CTAB). The reactions take place in air and water, and are quick, economical and amenable for scaling up. The synthesized nanocatalysts were characterized by electron microscopy techniques and energy dispersive X-ray analysis. Nafion membranes were embedded with the Au-Pt nanomaterials and analyzed by atomic force microscopy (AFM) and scanning electron microscopy (SEM) for their potential in direct methanol fuel cells applications.

  11. Pt-Ru Catalysts Prepared by a Modified Polyol Process for Direct Methanol Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    ZHANG Junmin; ZHU Fangfang; ZHANG Kunhua; LIU Weiping; GUAN Weiming

    2012-01-01

    Supported PtRu/C catalysts used in direct methanol fuel cells (DMFCs) were prepared by a new modified polyol method.Transmission electron microscopy (TEM),X-ray diffraction (XRD) and cyclic voltammograms (CVs) were carried out to characterize the morphology,composition and the electrochemical properties of the PtRu/C catalyst.The results revealed that the PtRu nanoparticles with small average particle size (≈2.5 nm),and highly dispersed on the carbon support.The PtRu/C catalyst exhibited high catalytic activity and anti-poisoned performance than that of the JM PtRu/C.It is imply that the modified polyol method is efficient for PtRu/C catalyst preparation.

  12. TOPICAL REVIEW: Micromachined polymer electrolyte membrane and direct methanol fuel cells—a review

    Science.gov (United States)

    Nguyen, Nam-Trung; Chan, Siew Hwa

    2006-04-01

    This review reports recent progress of the development of micromachined membrane-based fuel cells. The review first discusses the scaling law applied to this type of fuel cell. Impacts of miniaturization on the performance of membrane-based fuel cells are highlighted. This review includes only the two most common micro fuel cell types: proton exchange membrane micro fuel cells (PEMµFC) and direct methanol micro fuel cells (DMµFC). Furthermore, we only consider fuel cells with the active area of a single cell less than 1 square inch. Since the working principles of these fuel cell types are well known, the review only focuses on the choice of material and the design consideration of the components in the miniature fuel cell. Next, we compare and discuss the performance of different micro fuel cells published recently in the literature. Finally, this review gives an outlook on possible future development of micro fuel cell research.

  13. A comparative study of approaches to direct methanol fuel cells modelling

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, V.B.; Falcao, D.S.; Pinto, A.M.F.R. [Centro de Estudos de Fenomenos de Transporte, Departamento de Eng. Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Rangel, C.M. [Instituto Nacional de Engenharia, Tecnologia e Inovacao, Paco do Lumiar, 22,1649-038 (Portugal)

    2007-03-15

    Fuel cell modelling has received much attention over the past decade in an attempt to better understand the phenomena occurring within the cell. Mathematical models and simulation are needed as tools for design optimization of fuel cells, stacks and fuel cell power systems. Analytical, semi-empirical and mechanistic models for direct methanol fuel cells (DMFC) are reviewed. Effective models were until now developed describing the fundamental electrochemical and transport phenomena taking place in the cell. More research is required to develop models that can account for the two-phase flows occurring in the anode and cathode of the DMFC. The merits and demerits of the models are presented. Selected models of different categories are implemented and discussed. Finally, one of the selected simplified models is proposed as a computer-aided tool for real-time system level DMFC calculations. (author)

  14. Nafion Titania Nanotubes Nanocomposite Electrolytes for High-Temperature Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    Nonhlanhla Precious Cele

    2012-01-01

    Full Text Available Nafion-based nanocomposite membranes containing various amounts of titania nanotubes (TNTs as an inorganic filler have been prepared using melt-mixing method and have been investigated for proton exchange membrane applications. The one-dimensional TNTs have been prepared from potassium hydroxide using hydrothermal route and conventional heating. Nafion R1100 in a protonated form was used, and TNT contents were in a range of 0.5–2.0 wt%. The acid-treated composite membranes, at lowest inorganic additive content, exhibited improved properties in terms of thermal stability and methanol (MeOH permeability. The best performing nanocomposite was the membrane containing only 0.5 wt% TNTs showing ionic conductivity value of 7.2×10-2 S·cm-1 at 26°C and 100% of relative humidity.

  15. Enhancement of Hybrid SPEEK Based Polymer–Cyclodextrin-Silica Inorganic Membrane for Direct Methanol Fuel Cell Application

    Directory of Open Access Journals (Sweden)

    Tutuk Djoko Kusworo

    2017-06-01

      Keywords: Direct Methanol Fuel Cell, Poly(ether ether ketone, cyclodextrin-silica, sulfonation, ionic conductivity. Article History: Received January 18th 2017; Received in revised form April 21st 2017; Accepted June 22nd 2017; Available online How to Cite This Article: Kusworo, T.D., Hakim, M.F. and Hadiyanto, H. (2017 Enhancement of Hybrid SPEEK Based Polymer–Cyclodextrin-Silica Inorganic Membrane for Direct Methanol Fuel Cell Application. International Journal of Renewable Energy Development, 6(2, 165-170. https://doi.org/10.14710/ijred.6.2.165-170

  16. Recent advances in direct methanol fuel cells at Los Alamos National Laboratory

    Science.gov (United States)

    Ren, Xiaoming; Zelenay, Piotr; Thomas, Sharon; Davey, John; Gottesfeld, Shimshon

    This paper describes recent advances in the science and technology of direct methanol fuel cells (DMFCs) made at Los Alamos National Laboratory (LANL). The effort on DMFCs at LANL includes work devoted to portable power applications, funded by the Defense Advanced Research Project Agency (DARPA), and work devoted to potential transport applications, funded by the US DOE. We describe recent results with a new type of DMFC stack hardware that allows to lower the pitch per cell to 2 mm while allowing low air flow and air pressure drops. Such stack technology lends itself to both portable power and potential transport applications. Power densities of 300 W/l and 1 kW/l seem achievable under conditions applicable to portable power and transport applications, respectively. DMFC power system analysis based on the performance of this stack, under conditions applying to transport applications (joint effort with U.C. Davis), has shown that, in terms of overall system efficiency and system packaging requirements, a power source for a passenger vehicle based on a DMFC could compete favorably with a hydrogen-fueled fuel cell system, as well as with fuel cell systems based on fuel processing on board. As part of more fundamental studies performed, we describe optimization of anode catalyst layers in terms of PtRu catalyst nature, loading and catalyst layer composition and structure. We specifically show that, optimized content of recast ionic conductor added to the catalyst layer is a sensitive function of the nature of the catalyst. Other elements of membrane/electrode assembly (MEA) optimization efforts are also described, highlighting our ability to resolve, to a large degree, a well-documented problem of polymer electrolyte DMFCs, namely "methanol crossover". This was achieved by appropriate cell design, enabling fuel utilization as high as 90% in highly performing DMFCs.

  17. Full Flight Envelope Direct Thrust Measurement on a Supersonic Aircraft

    Science.gov (United States)

    Conners, Timothy R.; Sims, Robert L.

    1998-01-01

    Direct thrust measurement using strain gages offers advantages over analytically-based thrust calculation methods. For flight test applications, the direct measurement method typically uses a simpler sensor arrangement and minimal data processing compared to analytical techniques, which normally require costly engine modeling and multisensor arrangements throughout the engine. Conversely, direct thrust measurement has historically produced less than desirable accuracy because of difficulty in mounting and calibrating the strain gages and the inability to account for secondary forces that influence the thrust reading at the engine mounts. Consequently, the strain-gage technique has normally been used for simple engine arrangements and primarily in the subsonic speed range. This paper presents the results of a strain gage-based direct thrust-measurement technique developed by the NASA Dryden Flight Research Center and successfully applied to the full flight envelope of an F-15 aircraft powered by two F100-PW-229 turbofan engines. Measurements have been obtained at quasi-steady-state operating conditions at maximum non-augmented and maximum augmented power throughout the altitude range of the vehicle and to a maximum speed of Mach 2.0 and are compared against results from two analytically-based thrust calculation methods. The strain-gage installation and calibration processes are also described.

  18. Methyl phosphate formation as a major degradation mode of direct methanol fuel cells with phosphoric acid based electrolytes

    DEFF Research Database (Denmark)

    Aili, David; Vassiliev, Anton; Jensen, Jens Oluf

    2015-01-01

    Phosphoric acid and phosphoric acid doped polymer membranes are widely used as electrolytes in hydrogen based fuel cells operating at elevated temperatures. Such electrolytes have been explored for direct oxidation of methanol to further increase the versatility of the systems, however, with demo...

  19. Direct observation of hexamethylbenzenium radical cations generated during zeolite methanol-to-olefin catalysis: an ESR study.

    Science.gov (United States)

    Kim, Sun Jung; Jang, Hoi-Gu; Lee, Jun Kyu; Min, Hyung-Ki; Hong, Suk Bong; Seo, Gon

    2011-09-07

    The generation of hexamethylbenzenium radical cations as the key reaction intermediate in chabazite-type molecular sieve acids (i.e., H-SAPO-34 and H-SSZ-13) during the methanol-to-olefin process has been directly evidenced by ESR spectroscopy.

  20. Experimental determination and modeling of the phase behavior for the direct synthesis of dimethyl carbonate from methanol and carbon dioxide

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Musko, Nikolai E.; Baiker, Alfons

    2013-01-01

    This study focuses on the investigation of the phase behavior of mixtures relevant to the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. The bubble points of corresponding quaternary mixtures of varying composition were experimentally determined. The Cubic-Plus-Associati...

  1. Real-time monitoring of methanol concentration using a shear horizontal surface acoustic wave sensor for direct methanol fuel cell without reference liquid measurement

    Science.gov (United States)

    Tada, Kyosuke; Nozawa, Takuya; Kondoh, Jun

    2017-07-01

    In recent years, there has been an increasing demand for sensors that continuously measure liquid concentrations and detect abnormalities in liquid environments. In this study, a shear horizontal surface acoustic wave (SH-SAW) sensor is applied for the continuous monitoring of liquid concentrations. As the SH-SAW sensor functions using the relative measurement method, it normally needs a reference at each measurement. However, if the sensor is installed in a liquid flow cell, it is difficult to measure a reference liquid. Therefore, it is important to establish an estimation method for liquid concentrations using the SH-SAW sensor without requiring a reference measurement. In this study, the SH-SAW sensor is installed in a direct methanol fuel cell to monitor the methanol concentration. The estimated concentration is compared with a conventional density meter. Moreover, the effect of formic acid is examined. When the fuel temperature is higher than 70 °C, it is necessary to consider the influence of liquid conductivity. Here, an estimation method for these cases is also proposed.

  2. Self-assembled platinum nanoparticles on sulfonic acid-grafted graphene as effective electrocatalysts for methanol oxidation in direct methanol fuel cells

    Science.gov (United States)

    Lu, Jinlin; Li, Yanhong; Li, Shengli; Jiang, San Ping

    2016-02-01

    In this article, sulfonic acid-grafted reduced graphene oxide (S-rGO) were synthesized using a one-pot method under mild conditions, and used as Pt catalyst supports to prepare Pt/S-rGO electrocatalysts through a self-assembly route. The structure, morphologies and physicochemical properties of S-rGO were examined in detail by techniques such as atomic force microscope (AFM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The S-rGO nanosheets show excellent solubility and stability in water and the average particle size of Pt nanoparticles supported on S-rGO is ~3.8 nm with symmetrical and uniform distribution. The electrocatalytic properties of Pt/S-rGO were investigated for methanol oxidation reaction (MOR) in direct methanol fuel cells (DMFCs). In comparison to Pt supported on high surface area Vulcan XC-72 carbon (Pt/VC) and Pt/rGO, the Pt/S-rGO electrocatalyst exhibits a much higher electrocatalytic activity, faster reaction kinetics and a better stability. The results indicate that Pt/S-rGO is a promising and effective electrocatalyst for MOR of DMFCs.

  3. High throughput evaluation of perovskite-based anode catalysts for direct methanol fuel cells

    Science.gov (United States)

    Deshpande, Kishori; Mukasyan, Alexander; Varma, Arvind

    Liquid feed direct methanol fuel cells (DMFC) are promising candidates for portable power applications. However, owing to the problems associated with expensive Pt-based catalysts, viz., CO poisoning, a promising approach is to use complex oxides of the type ABO 3 (A = Sr, Ce, La, etc. and B = Co, Fe, Ni, Pt, Ru, etc.). In the current work, a variety of ABO 3 and A 2BO 4 type non-noble and partially substituted noble metal high surface area compounds were synthesized by an effective and rapid aqueous combustion synthesis (CS). Their catalytic activity was evaluated by using "High Throughput Screening Unit"-NuVant System, which compares up to 25 compositions simultaneously under DMFC conditions. It was found that the Sr-based perovskites showed performance comparable with the standard Pt-Ru catalyst. Further, it was observed that the method of doping SrRuO 3 with Pt influenced the activity. Specifically, platinum added during aqueous CS yielded better catalyst than when added externally at the ink preparation stage. Finally, it was also demonstrated that the presence of SrRuO 3 significantly enhanced the catalytic properties of Pt, leading to superior performance even at lower noble metal loadings.

  4. Reliability and availability analysis of low power portable direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Sisworahardjo, N.S. [School of Electrical Engineering and Informatics, Bandung Institute of Technology, Bandung, 40132 (Indonesia); Department of Electrical and Computer Engineering, University of South Alabama, Mobile, AL 36688 (United States); Alam, M.S.; Aydinli, G. [Department of Electrical and Computer Engineering, University of South Alabama, Mobile, AL 36688 (United States)

    2008-03-01

    This paper presents a methodology for modeling and calculating the reliability and availability of low power portable direct methanol fuel cells (DMFCs). System reliability and availability are critical factors for improving market acceptance and for determining the competitiveness of the low power DMFC. Two techniques have been used for analyzing the system reliability and availability requirements for various system components. Reliability block diagram (RBD) is formed based on the failure rates of irreparable system components. A state-space method is developed to calculate system availability using the Markov model (MM). The state-space method incorporates three different states - operational, derated, and fully faulted states. Since most system components spend their lifetime in performing normal functional task, this research is focused mainly on this operational period. The failure and repair rates for repairable DMFC systems are estimated on the basis of a homogeneous Poisson process (HPP) and exponential distribution. Extensive analytical modeling and simulation study has been performed to verify the effectiveness of the proposed technique. (author)

  5. Reliability and availability analysis of low power portable direct methanol fuel cells

    Science.gov (United States)

    Sisworahardjo, N. S.; Alam, M. S.; Aydinli, G.

    This paper presents a methodology for modeling and calculating the reliability and availability of low power portable direct methanol fuel cells (DMFCs). System reliability and availability are critical factors for improving market acceptance and for determining the competitiveness of the low power DMFC. Two techniques have been used for analyzing the system reliability and availability requirements for various system components. Reliability block diagram (RBD) is formed based on the failure rates of irreparable system components. A state-space method is developed to calculate system availability using the Markov model (MM). The state-space method incorporates three different states-operational, derated, and fully faulted states. Since most system components spend their lifetime in performing normal functional task, this research is focused mainly on this operational period. The failure and repair rates for repairable DMFC systems are estimated on the basis of a homogeneous Poisson process (HPP) and exponential distribution. Extensive analytical modeling and simulation study has been performed to verify the effectiveness of the proposed technique.

  6. Development of Polymer Electrolyte Mambrane (PEM) from Bisphonol S for Direct Methanol Fuel Cell (DMFC)

    Science.gov (United States)

    Changkhamchom, Sairung

    2009-03-01

    The currently used Proton Exchange Membrane (PEM) in a Direct Methanol Fuel Cell (DMFC) is Nafion^, an excellent proton conductor in a fully hydrated membrane. However, it has major drawbacks, such as very high cost, and loss of conductivity at elevated temperature and low humidity. In this work, a novel PEM based on sulfonated poly(ether ether ketone) (S-PEEK). Poly(ether ether ketone) (PEEK) was synthesized by the nucleophilic aromatic substitution polycondensation of Bisphonol-S and 4,4'-difluorobenzophenone for system A, and Bisphenol S and 4,4'-dichlorobenzophenone for system B. Bisphenol-S helps to increase the thermal stability due to its high melting point (245^oC). The post-sulfonation reaction was performed by using concentrated sulfuric acid. Sulfonated poly(ether ether ketone) (S-PEEK) samples were characterized by FTIR and ^1H-NMR to confirm the chemical structure of the S-PEEK, and by TGA to investigate the thermal property.

  7. Non-syngas direct steam reforming of methanol to hydrogen and carbon dioxide at low temperature.

    Science.gov (United States)

    Yu, Kai Man Kerry; Tong, Weiyi; West, Adam; Cheung, Kevin; Li, Tong; Smith, George; Guo, Yanglong; Tsang, Shik Chi Edman

    2012-01-01

    A non-syngas direct steam reforming route is investigated for the conversion of methanol to hydrogen and carbon dioxide over a CuZnGaO(x) catalyst at 150-200 °C. This route is in marked contrast with the conventional complex route involving steam reformation to syngas (CO/H2) at high temperature, followed by water gas shift and CO cleanup stages for hydrogen production. Here we report that high quality hydrogen and carbon dioxide can be produced in a single-step reaction over the catalyst, with no detectable CO (below detection limit of 1 ppm). This can be used to supply proton exchange membrane fuel cells for mobile applications without invoking any CO shift and cleanup stages. The working catalyst contains, on average, 3-4 nm copper particles, alongside extremely small size of copper clusters stabilized on a defective ZnGa2O4 spinel oxide surface, providing hydrogen productivity of 393.6 ml g(-1)-cat h(-1) at 150 °C.

  8. Supported PtRu on mesoporous carbons for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Arbizzani, Catia; Beninati, Sabina; Soavi, Francesca; Varzi, Alberto; Mastragostino, Marina [University of Bologna, Department of Metal Science, Electrochemistry and Chemical Techniques, via San Donato 15, 40127 Bologna (Italy)

    2008-12-01

    We prepared and characterized several cryogel mesoporous carbons of different pore size distribution and report the catalytic activity of PtRu supported on mesoporous carbons of pore size >15 nm in passive and in active direct methanol fuel cells (DMFCs). At room temperature (RT), the specific maximum power of the passive DMFCs with mesoporous carbon/PtRu systems as anode was in the range 3-5 W g{sup -1}. Passive DMFC assembly and RT tests limit the performance of the electrocatalytic systems and the anodes were thus tested in active DMFCs at 30, 60 and 80 C. Their responses were also compared to those of commercial Vulcan carbon/PtRu. At 80 C, the specific maximum power of the active DMFC with C656/PtRu was 37 W g{sup -1} and the required amount of Pt per kW estimated at 0.4 V cell voltage was 31 g kW{sup -1}, a value less than half that of Vulcan carbon/PtRu. (author)

  9. Developments for improved direct methanol fuel cell stacks for portable power

    Energy Technology Data Exchange (ETDEWEB)

    Cremers, C.; Stimming, U. [Bavarian Center for Applied Energy Research, ZAE Bayern, Abteilung 1, Walther-Meissner-Str. 6, D-85748 Garching (Germany); Technische Universitaet Muenchen, Department of Physics E19, James-Franck-Str. 1, D-85748 Garching (Germany); Scholz, M.; Seliger, W. [Bavarian Center for Applied Energy Research, ZAE Bayern, Abteilung 1, Walther-Meissner-Str. 6, D-85748 Garching (Germany); Racz, A. [Technische Universitaet Muenchen, Department of Physics E19, James-Franck-Str. 1, D-85748 Garching (Germany); Knechtel, W.; Rittmayr, J.; Grafwallner, F.; Peller, H. [ET EnergieTechnologie GmbH, Eugen-Saenger-Ring 4, D-85649 Brunnthal-Nord (Germany)

    2007-02-15

    Different aspects of the improvement of direct methanol fuel cell (DMFC) systems for portable power generation are investigated, in a project funded by the Bavarian state. The materials research focuses on the development of improved catalysts, in particular for the oxygen reduction reaction. Some recent results on supported ruthenium selenium catalysts are reported. In parallel, tests on other fuel cell materials are performed using MEAs made from industrial unsupported catalysts as the reference. These standard MEAs have catalyst loadings of about 11 mg cm{sup -2} and, at high air flux, can deliver current densities of about 500 mA cm{sup -2} and 100 mA cm{sup -2} at 110 C and 50 C, respectively. At low air flux and 50 C, current densities between 60 and 80 mA cm{sup -2} are possible rate at 500 mV. Using these MEAs, different commercial gas diffusion materials are tested as the cathode backing. Thus, it is found that the Sigracet materials by SGL Carbon are the most suitable for operation at a low air flux. Finally, a demonstration stack, comprised of up to ten cells, is developed using graphite PVDF compound bipolar plates by SGL Carbon. As will be reported, this stack shows a high homogeneity of cell voltages and stable operation under relevant conditions, using standard MEAs. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  10. Short term changes in methanol emission and pectin methylesterase activity are not directly affected by light in Lycopersicon esculentum

    Directory of Open Access Journals (Sweden)

    M. T. Lerdau

    2011-04-01

    Full Text Available Plants are an important source of atmospheric methanol (MeOH, the second most abundant organic gas after methane. Factors regulating phytogenic MeOH production are not well constrained in current MeOH emission models. Previous studies have indicated that light may have a direct influence on MeOH production. As light is known to regulate cell wall expansion, it was predicted that light would stimulate MeOH production through the pectin methylesterase (PME pathway. MeOH emissions normalized for stomatal conductance (gs did not, however, increase with light over short time scales (20–30 min. After experimentally controlling for gs and temperature, no light activation of PME activity or MeOH emission was observed. The results clearly demonstrate that light does not directly influence short-term changes in MeOH production and emission. Our data suggest that substrate limitation may be important in regulating MeOH production over short time scales. Future investigation of the long-term impacts of light on MeOH production may increase understanding of MeOH emission dynamics at the seasonal time scale.

  11. Short term changes in methanol emission and pectin methylesterase activity are not directly affected by light in Lycopersicon esculentum

    Directory of Open Access Journals (Sweden)

    M. T. Lerdau

    2011-01-01

    Full Text Available Plants are an important source of atmospheric methanol (MeOH, the second most abundant organic gas after methane. Factors regulating phytogenic MeOH production are not well constrained in current MeOH emission models. Previous studies have indicated that light may have a direct influence on MeOH production. As light is known to regulate cell wall expansion, it was predicted that light would stimulate MeOH production through the pectin methylesterase (PME pathway. MeOH emissions normalized for stomatal conductance (gs did not, however, increase with light over short time scales (20–30 min. After experimentally controlling for gs and temperature, no light activation of PME activity or MeOH emission was observed. The results clearly demonstrate that light does not directly influence short-term changes in MeOH production and emission. Our data suggest that substrate limitation may be important in regulating MeOH production over short time scales. Future investigation of the long-term impacts of light on MeOH production may increase understanding of MeOH emission dynamics at the seasonal time scale.

  12. Heat and mass transfer effects in a direct methanol fuel cell: A 1D model

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, V.B.; Falcao, D.S.; Pinto, A.M.F.R. [Centro de Estudos de Fenomenos de Transporte, Departamento de Eng. Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Rangel, C.M. [INETI - Unidade de Electroquimica e Materiais, Paco do Lumiar, 22,1649-038 (Portugal)

    2008-07-15

    Models are a fundamental tool for the design process of fuel cells and fuel cell systems. In this work, a steady-state, one-dimensional model accounting for coupled heat and mass transfer, along with the electrochemical reactions occurring in the DMFC, is presented. The model output is the temperature profile through the cell and the water balance and methanol crossover between the anode and the cathode. The model predicts the correct trends for the influence of current density and methanol feed concentration on both methanol and water crossover. The model estimates the net water transfer coefficient through the membrane, {alpha}, a very important parameter to describe water management in the DMFC. Suitable operating ranges can be set up for different MEA structures maintaining the crossover of methanol and water within acceptable levels. The model is rapidly implemented and is therefore suitable for inclusion in real-time system level DMFC calculations. (author)

  13. Electrodeposited Pt and Pt-Sn nanoparticles on Ti as anodes for direct methanol fuel cells

    Institute of Scientific and Technical Information of China (English)

    Hanaa B HASSAN

    2009-01-01

    Electro-oxidation of methanol was studied on titanium supported nanocrystallite Pt and Ptx-Sny catalysts prepared by electrodeposition techniques. Their electro-catalytic activities were studied in 0.5mol/L H2SO4 and compared to those of a smooth Pt, Pt/Pt and Pt-Sn/Pt electrodes. Platinum was deposited on Ti by galvanostatic and potentiostatic techniques. X-ray diffractometer (XRD) and energy dispersive X-ray (EDX) techniques were applied in order to investigate the chemical composition and the phase structure of the modified electrodes. Scanning electron microscopy (SEM) was used to characterize the surface morphology and to correlate the results obtained from the two electrochemical deposition methods. Results show that modified Pt/Ti electrodes prepared by the two methods have comparable performance and enhanced catalytic activity towards methanol electro-oxidation compared to Pt/Pt and smooth Pt electrodes. Steady state Tafel plots experiments show a higher rate of methanol oxidation on a Pt/Ti catalyst than that on a smooth Pt. Introduction of a small amount of Sn deposited with Pt improves the catalytic activity and the stability of prepared electrode with time as indicated from the cyclic votlammetry and the chronoamperometric experiments. The effect of variations in the composition for binary catalysts of the type Ptx-Sny/Ti towards the methanol oxidation reaction is reported. Consequently, the Ptx-Sny/Ti (x∶y (8∶1), molar ratio) catalyst is a very promising one for methanol oxidation.

  14. Nanoporous separator and low fuel concentration to minimize crossover in direct methanol laminar flow fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Hollinger, A.S. [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 Green Street, Urbana, IL 61801 (United States); Maloney, R.J.; Jayashree, R.S. [Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S. Matthews Avenue, Urbana, IL 61801 (United States); Natarajan, D.; Markoski, L.J. [INI Power Systems, 175 Southport Drive, Suite 100, Morrisville, NC 27560 (United States); Kenis, P.J.A. [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 Green Street, Urbana, IL 61801 (United States); Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S. Matthews Avenue, Urbana, IL 61801 (United States)

    2010-06-01

    Laminar flow fuel cells (LFFCs) overcome some key issues - most notably fuel crossover and water management - that typically hamper conventional polymer electrolyte-based fuel cells. Here we report two methods to further minimize fuel crossover in LFFCs: (i) reducing the cross-sectional area between the fuel and electrolyte streams, and (ii) reducing the driving force of fuel crossover, i.e. the fuel concentration gradient. First, we integrated a nanoporous tracketch separator at the interface of the fuel and electrolyte streams in a single-channel LFFC to dramatically reduce the cross-sectional area across which methanol can diffuse. Maximum power densities of 48 and 70 mW cm{sup -2} were obtained without and with a separator, respectively, when using 1 M methanol. This simple design improvement reduces losses at the cathode leading to better performance and enables thinner cells, which is attractive in portable applications. Second, we demonstrated a multichannel cell that utilizes low methanol concentrations (<300 mM) to reduce the driving force for methanol diffusion to the cathode. Using 125 mM methanol as the fuel, a maximum power density of 90 mW cm{sup -2} was obtained. This multichannel cell further simplifies the LFFC design (one stream only) and its operation, thereby extending its potential for commercial application. (author)

  15. Application of green chemistry techniques to prepare electrocatalysts for direct methanol fuel cells.

    Science.gov (United States)

    Shimizu, Kenichi; Wang, Joanna S; Wai, Chien M

    2010-03-25

    A series of green techniques for synthesizing carbon nanotube-supported platinum nanoparticles and their high electrocatalytic activity toward methanol fuel cell applications are reported. The techniques utilize either the supercritical fluid carbon dioxide or water as a medium for depositing platinum nanoparticles on surfaces of multiwalled or single-walled carbon nanotubes. The catalytic properties of the carbon nanotubes-supported Pt nanoparticle catalysts prepared by four different techniques are compared for anodic oxidation of methanol and cathodic reduction of oxygen using cyclic voltammetry. One technique using galvanic exchange of Pt(2+) in water with zerovalent iron present on the surfaces of as-grown single-walled carbon nanotubes produces a Pt catalyst that shows an unusually high catalytic activity for reduction of oxygen but a negligible activity for oxidation of methanol. This fuel-selective catalyst may have a unique application as a cathode catalyst in methanol fuel cells to alleviate the problems caused by crossover of methanol through the polymer electrolyte membrane.

  16. 点燃式缸内直喷甲醇发动机甲醛和未燃甲醇排放特性%Formaldehyde and unburned methanol emissions from a spark-ignition direct-injection methanol engine

    Institute of Scientific and Technical Information of China (English)

    宫长明; 张自雷; 贾京龙; 崔峰云; 郑伟

    2012-01-01

    The effects of methanol injection timing, ignition timing and excess air ratio on formaldehyde and unburned methanol emissions from a spark-ignition direct-injection methanol engine under homogenous combustion mode were investigated experimentally by means of a measurement method in which the gas chromatography and the liquid chromatography were used to separate and measure formaldehyde and methanol. The results show that the methanol injection timing, ignition timing and excess air ratio affect significantly the formaldehyde and unburned methanol emissions from a spark- ignition directqnjection methanol engine. The variations in emitted formaldehyde and unburned methanol show opposite tendencies with the variations in the methanol injection timing, ignition timing and excess air ratio. Retarding methanol injection timing, advancing ignition timing and using lean mixture decrease formaldehyde emission.%基于气相色谱和液相色谱相结合的甲醛和甲醇测量方法,试验研究了点燃式缸内直喷甲醇发动机甲醇喷射正时、点火正时和过量空气系数在均质燃烧模式下对甲醛和未燃甲醇排放的影响。试验结果表明,甲醇喷射正时、点火正时和过量空气系数对该发动机甲醛和未燃甲醇排放有显著影响,并且甲醛和未燃甲醇排放随喷射正时、点火正时和过量空气系数的变化呈相反的变化趋势。推迟喷射甲醇、提前点火及采用稀混合气可以降低甲醛排放。

  17. Influence of current collectors design on the performance of a silicon-based passive micro direct methanol fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, J.P.; Sabate, N.; Santander, J.; Torres-Herrero, N.; Gracia, I.; Ivanov, P.; Fonseca, L.; Cane, C. [Instituto de Microelectronica de Barcelona, IMB-CNM (CSIC), Campus UAB, 08193 Bellaterra, Barcelona (Spain)

    2009-10-20

    In this paper, the influence of current collector open ratio on the performance of a passive micro direct methanol fuel cell is evaluated. The device is based on a hybrid approach consisting of two microfabricated silicon current collectors assembled together with a commercial membrane electrode assembly. The characterization was performed by measuring polarization curves of the fuel cell using current collectors with different open ratios on anode and cathode. Results show that the way in which the open ratio of current collectors is combined has an effect not only on the output power but also on the repeatability of polarization curves. This study allows the setting of some general design rules for current collectors of passive micro direct methanol fuel cells. (author)

  18. Ni2P Makes Application of the PtRu Catalyst Much Stronger in Direct Methanol Fuel Cells.

    Science.gov (United States)

    Chang, Jinfa; Feng, Ligang; Liu, Changpeng; Xing, Wei

    2015-10-12

    PtRu is regarded as the best catalyst for direct methanol fuel cells, but the performance decay resulting from the loss of Ru seriously hinders commercial applications. Herein, we demonstrated that the presence of Ni2 P largely reduces Ru loss, which thus makes the application of PtRu much stronger in direct methanol fuel cells. Outstanding catalytic activity and stability were observed by cyclic voltammetry. Upon integrating the catalyst material into a practical direct methanol fuel cell, the highest maximum power density was achieved on the PtRu-Ni2P/C catalyst among the reference catalysts at different temperatures. A maximum power density of 69.9 mW cm(-2) at 30 °C was obtained on PtRu-Ni2P/C, which is even higher than the power density of the state-of-the-art commercial PtRu catalyst at 70 °C (63.1 mW cm(-2)). Moreover, decay in the performance resulting from Ru loss was greatly reduced owing to the presence of Ni2 P, which is indicative of very promising applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Preparation and characterization of anode catalysts for the direct alcohol fuel cells (DAFC): methanol and ethanol

    CSIR Research Space (South Africa)

    Modibedi, M

    2007-11-01

    Full Text Available The development of high performance electrode materials has been the key research objective in the field of direct alcohol fuel cells (DAFC) [1, 2, and 3]. A promising way to attain higher catalytic performance is to add a third element to the best...

  20. Characterization and fuel cell performance analysis of polyvinylalcohol-mordenite mixed-matrix membranes for direct methanol fuel cell use

    Energy Technology Data Exchange (ETDEWEB)

    Uctug, Fehmi Goerkem, E-mail: gorkem.uctug@bahcesehir.edu.t [University of Manchester, School of Chemical Engineering and Analytical Science, M60 1QD (United Kingdom); Holmes, Stuart M. [University of Manchester, School of Chemical Engineering and Analytical Science, M60 1QD (United Kingdom)

    2011-10-01

    Highlights: > We investigated the availability of PVA-mordenite membranes for DMFC use. > We measured the methanol permeability of PVA-mordenite membranes via pervaporation. > We did the fuel cell testing of these membranes, which had not been done before. > We showed that PVA-mordenite membranes have poorer DMFC performance than Nafion. > Membrane performance can be improved by increasing the proton conductivity of PVA. - Abstract: Polyvinylalcohol-mordenite (PVA-MOR) mixed matrix membranes were synthesized for direct methanol fuel cell (DMFC) use. For the structural and the morphological characterization, Scanning Electron Microscopy and Thermal Gravimetric Analysis methods were used. Zeolite distribution within the polymer matrix was found to be homogeneous. An impedance spectroscope was used to measure the proton conductivity. In order to obtain information about methanol permeation characteristics, swelling tests and a series of pervaporation experiments were carried out. 60-40 wt% PVA-MOR membranes were found to give the optimum transport properties. Proton conductivity of these membranes was found to be slightly lower than that of Nafion117{sup TM} whereas their methanol permeability was at least two orders of magnitude lower than Nafion117{sup TM}. DMFC performance of the PVA-MOR membranes was also measured. The inferior DMFC performance of PVA-MOR membranes was linked to drying in the fuel cell medium and the consequent proton conductivity loss. Their performance was improved by adding a dilute solution of sulfuric acid into the feed methanol solution. Future studies on the improvement of the proton conductivity of PVA-MOR membranes, especially via sulfonation of the polymer matrix, can overcome the low-performance problem associated with insufficient proton conductivity.

  1. Preparation and characterization of SMA/S-POSS hybrid membranes for direct methanol fuel cell applications

    Institute of Scientific and Technical Information of China (English)

    WANG Erdong; SHI Pengfei; CHANG Young-wook

    2006-01-01

    A novel sulfonated polyhedral oligomeric silsesquioxane(S-POSS) monomer was synthesized successfully in this article. S-POSS acted as a donor of sulfonic acid group and reacted with poly(styrene-co-maleic anhydride) (SMA). FT-IR spectroscopy confirmed the modification through introduction of peaks characteristic of ester linkages and carboxylic groups. The SMA/S-POSS hybrid membranes were fabricated from different S-POSS contents. The proton conductivity and methanol permeability of the hybrid membranes were studied with changing S-POSS content from 5wt.% to 30wt.%. It was found that the proton conductivity and the methanol permeability were dependent on the S-POSS content. Both of proton conductivity and methanol permeability properties improve with increasing S-POSS content. The proton conductivities of the hybrid membranes are in the range of 10-3-10-2 S·cm-1,and the range of methanol permeabilities was between 10-8 and 10-7 cm2·s-1. The membranes show good thermal properties characterized by thermogravimetric analysis (TGA).

  2. Hybridization and control of a mobile direct methanol fuel cell system; Hybridisierung und Regelung eines mobilen Direktmethanol-Brennstoffzellen-Systems

    Energy Technology Data Exchange (ETDEWEB)

    Wilhelm, Joerg Christoph

    2010-07-01

    Direct methanol fuel cells (DMFCs) are characterized by the fact that they directly convert the chemical energy of the liquid fuel methanol into electrical energy. Methanol has a high energy density and can be stored relatively easily. Due to these advantages, direct methanol fuel cell systems are suitable, for example, as a battery replacement for light-traction applications in the kW class. Since refuelling is much faster than recharging a battery, almost interruption-free operation is possible. The aim of this thesis is therefore to develop a direct methanol fuel cell system for light-traction applications. The systems technology development and characterization of a mobile direct methanol fuel cell system is initially examined in general and then applied to the example of a horizontal order picker, a type of forklift truck. A hybridization and control concept is developed for this type of truck. The procedure is structured into the theoretical characterization of the application, the development of theoretical concepts and a concluding systems analysis using data from the test stand and simulations. The characteristic driving cycle of the application results from the characterization. The concept development is based on key data such as maximum peak power during acceleration and braking as well as average power. The two-stage theoretical development of a hybridization concept is based on a pure fuel cell vehicle. A systems analysis of all possible concepts with respect to the criteria of fuel cell power, total system efficiency and dynamic fuel cell loading eventually leads to the preferred concept of indirect coupling. A cascade controller with map control, the control concept developed for this purpose, keeps the energy storage unit at a constant state of charge and provides for the fuel cell aging protection as well as aging detection. The driving cycle, operational states of the vehicle and the efficiencies of the individual components play a decisive role

  3. Mathematical Modeling of Transport Phenomena in Polymer Electrolyte and Direct Methanol Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Birgersson, Erik

    2004-02-01

    This thesis deals with modeling of two types of fuel cells: the polymer electrolyte fuel cell (PEFC) and the direct methanol fuel cell (DMFC), for which we address four major issues: a) mass transport limitations; b) water management (PEFC); c) gas management (DMFC); d) thermal management. Four models have been derived and studied for the PEFC, focusing on the cathode. The first exploits the slenderness of the cathode for a two-dimensional geometry, leading to a reduced model, where several non dimensional parameters capture the behavior of the cathode. The model was extended to three dimensions, where four different flow distributors were studied for the cathode. A quantitative comparison shows that the interdigitated channels can sustain the highest current densities. These two models, comprising isothermal gas phase flow, limit the studies to (a). Returning to a two-dimensional geometry of the PEFC, the liquid phase was introduced via a separate flow model approach for the cathode. In addition to conservation of mass, momentum and species, the model was extended to consider simultaneous charge and heat transfer for the whole cell. Different thermal, flow fields, and hydrodynamic conditions were studied, addressing (a), (b) and (d). A scale analysis allowed for predictions of the cell performance prior to any computations. Good agreement between experiments with a segmented cell and the model was obtained. A liquid-phase model, comprising conservation of mass, momentum and species, was derived and analyzed for the anode of the DMFC. The impact of hydrodynamic, electrochemical and geometrical features on the fuel cell performance were studied, mainly focusing on (a). The slenderness of the anode allows the use of a narrow-gap approximation, leading to a reduced model, with benefits such as reduced computational cost and understanding of the physical trends prior to any numerical computations. Adding the gas-phase via a multiphase mixture approach, the gas

  4. Bimetallic Nickel/Ruthenium Catalysts Synthesized by Atomic Layer Deposition for Low-Temperature Direct Methanol Solid Oxide Fuel Cells.

    Science.gov (United States)

    Jeong, Heonjae; Kim, Jun Woo; Park, Joonsuk; An, Jihwan; Lee, Tonghun; Prinz, Fritz B; Shim, Joon Hyung

    2016-11-09

    Nickel and ruthenium bimetallic catalysts were heterogeneously synthesized via atomic layer deposition (ALD) for use as the anode of direct methanol solid oxide fuel cells (DMSOFCs) operating in a low-temperature range. The presence of highly dispersed ALD Ru islands over a porous Ni mesh was confirmed, and the Ni/ALD Ru anode microstructure was observed. Fuel cell tests were conducted using Ni-only and Ni/ALD Ru anodes with approximately 350 μm thick gadolinium-doped ceria electrolytes and platinum cathodes. The performance of fuel cells was assessed using pure methanol at operating temperatures of 300-400 °C. Micromorphological changes of the anode after cell operation were investigated, and the content of adsorbed carbon on the anode side of the operated samples was measured. The difference in the maximum power density between samples utilizing Ni/ALD Ru and Pt/ALD Ru, the latter being the best catalyst for direct methanol fuel cells, was observed to be less than 7% at 300 °C and 30% at 350 °C. The improved electrochemical activity of the Ni/ALD Ru anode compared to that of the Ni-only anode, along with the reduction of the number of catalytically active sites due to agglomeration of Ni and carbon formation on the Ni surface as compared to Pt, explains this decent performance.

  5. Highly dispersed Pt-Ni nanoparticles on nitrogen-doped carbon nanotubes for application in direct methanol fuel cells.

    Science.gov (United States)

    Jiang, Shujuan; Ma, Yanwen; Tao, Haisheng; Jian, Guoqiang; Wang, Xizhang; Fan, Yining; Zhu, Jianmin; Hu, Zheng

    2010-06-01

    Binary Pt-Ni alloyed nanoparticles supported on nitrogen-doped carbon nanotubes (NCNTs) have been facilely constructed without pre-modification by making use of the active sites in NCNTs due to the N-participation. So-obtained binary Pt-Ni alloyed nanoparticles have been highly dispersed on the outer surface of the support with the size of about 3-4 nm. The electrochemical properties of the catalysts for methanol oxidation have been systematically evaluated. Binary Pt-Ni alloyed composites with molar ratio (Pt:Ni) of 3:2 and 3:1 present enhanced electrocatalytic activities and improved tolerance to CO poisoning as well as the similar stability, in comparison with the commercial Pt/C catalyst and the monometallic Pt/NCNTs catalysts. These results imply that so-constructed nanocomposite catalysts have the potential for applications in direct methanol fuel cells.

  6. Optimization for microwave-assisted direct liquefaction of bamboo residue in glycerol/methanol mixtures

    Institute of Scientific and Technical Information of China (English)

    Jiulong Xie; Jinqiu Qi; Chungyun Hse; Todd F. Shupe

    2015-01-01

    Bamboo residues were liquefied in a mixture of glycerol and methanol in the presence of sulfuric acid using microwave energy. We investigated the effects of lique-faction conditions, including glycerol/methanol ratio, liq-uefaction temperature, and reaction time on the conversion yield. The optimal liquefaction conditions were under the temperature of 120 °C, the reaction time of 7 min, the glycerol–methanol–bamboo ratio of 8/0/2 (W/W), and the microwave power of 300 W. Maximum conversion yield was 96.7%. The liquid products were separated into two contents (water soluble part and precipitate part) by addi-tion of a sufficient amount of water. By Fourier transform infrared (FT-IR), the water soluble content mainly con-tained glycerol and its derivate and carbohydrate degra-dation products, and the precipitate content was mainly lignin derivatives.

  7. Preparation and characterization of the PVDF-based composite membrane for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu Qian; Song Laizhou; Zhang Zhihui; Liu Xiaowei [Department of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2010-07-01

    The polyvinylidene fluoride-sulfonated polystyrene composite membrane with proton exchange performance, denoted as PVDF-SPS, was prepared using a thermally induced polymerization technique. The thermal stability of the PVDF-SPS composite membrane was investigated using thermogravimetric (TG) analysis. The complex formation of the composite membrane was ascertained by Fourier transform infrared spectroscopy (FTIR). The surface compositions of the PVDF-SPS membrane were analyzed using X-ray photoelectron spectroscopy (XPS). The morphology of the composite membrane was characterized by environmental scanning electron microscopy (ESEM). The proton conductivity of the PVDF-SPS membrane was measured using impedance spectroscopy in the hydrated condition. The PVDF-SPS membrane has a stronger hydrophilic character than the pristine PVDF membrane and the polyvinylidene fluoride-polystyrene composite membrane (PVDF-PS), which is caused by the incorporation of sulfonic acid groups. The proton conductivity and the methanol permeability of the PVDF-SPS membrane measured at 298 K are 29.3 mS.cm-1 and 8.6x10-8 cm2.s-1, respectively. Although PVDF-SPS composite membrane possesses the lower oxidative stability than Nafion-117 membrane, the composite membrane displays lower methanol permeability than the Nafion-117 membrane, and the selectivity (the ratio of proton conductivity and methanol permeability) of the composite membrane is almost 20 times than that of Nafion-117.

  8. Highly stable ionic-covalent cross-linked sulfonated poly(ether ether ketone) for direct methanol fuel cells

    Science.gov (United States)

    Lei, Linfeng; Zhu, Xingye; Xu, Jianfeng; Qian, Huidong; Zou, Zhiqing; Yang, Hui

    2017-05-01

    A novel ionic cross-linked sulfonated poly(ether ether ketone) containing equal content of sulfonic acid and pendant tertiary amine groups (TA-SPEEK) has been initially synthesized for the application in direct methanol fuel cells (DMFCs). By adjusting the ratio of p-xylene dibromide to tertiary amine groups of TA-SPEEK, a series of ionic-covalent cross-linked membranes (C-SPEEK-x) with tunable degree of cross-linking are prepared. Compared with the pristine membrane, the ionic and ionic-covalent cross-linked proton exchange membranes (PEMs) exhibit reduced methanol permeability and improved mechanical properties, dimensional and oxidative stability. The proton conductivity and methanol selectivity of protonated TA-SPEEK and C-SPEEK-x at 25 °C is up to 0.109 S cm-1 and 3.88 × 105 S s cm-3, respectively, which are higher than that of Nafion 115. The DMFC incorporating C-SPEEK-25 exhibits a maximum power density as high as 35.3 mW cm-2 with 4 M MeOH at 25 °C (31.8 mW cm-2 for Nafion 115). Due to the highly oxidative stability of the membrane, no obvious performance degradation of the DMFC is observed after more than 400 h operation, indicating such cost-effective ionic-covalent cross-linked membranes have substantial potential as alternative PEMs for DMFC applications.

  9. Vertically aligned carbon nanotubes/carbon fiber paper composite to support Pt nanoparticles for direct methanol fuel cell application

    Science.gov (United States)

    Zhang, Jing; Yi, Xi-bin; Liu, Shuo; Fan, Hui-Li; Ju, Wei; Wang, Qi-Chun; Ma, Jie

    2017-03-01

    Vertically aligned carbon nanotubes (VACNTs) grown on carbon fiber paper (CFP) by plasma enhanced chemical vapor deposition is introduced as a catalyst support material for direct methanol fuel cells (DMFCs). Well dispersed Pt nanoparticles on VACNTs surface are prepared by impregnation-reduction method. The VACNTs on CFP possess well-maintained alignment, large surface area and good electrical conductivity, which leading to the formation of Pt particles with a smaller size and enhance the Pt utilization rate. The structure and nature of resulting Pt/VACNTs/CFP catalysts for methanol oxidation are investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD) and scanning electron microscope (SEM). With the aid of VACNTs, well-dispersed Pt catalysts enable the reversibly rapid redox kinetic since electron transport efficiently passes through a one-dimensional pathway, which leads to enhance the catalytic activity and Pt utilization rate. Compared with the Pt/XC-72/CFP electrode, the electrochemical measurements results display that the Pt/VACNTs/CFP catalyst shows much higher electrocatalytic activity and better stability for methanol oxidation. In addition, the oxidation current from 200 to 1200 s decayed more slowly for the Pt/VACNTs/CFP than that of the Pt/XC-72/CFP catalysts, indicating less accumulation of adsorbed CO species. All those results imply that the Pt/VACNTs/CFP has a great potential for applications in DMFCs.

  10. Position dependent analysis of membrane electrode assembly degradation of a direct methanol fuel cell via electrochemical impedance spectroscopy

    Science.gov (United States)

    Hartmann, Peter; Zamel, Nada; Gerteisen, Dietmar

    2013-11-01

    The performance of a direct methanol fuel cell MEA degraded during an operational period of more than 3000 h in a stack is locally examined using electrochemical impedance spectroscopy. Therefore, after disassembling the MEA is cut into small pieces and analyzed in a 1 cm2 test cell. Using a reference electrode, we were capable of measuring the anode and cathode spectra separately. The spectra of the segments at different positions do not follow a specified trend from methanol inlet to outlet of the stack flow field. The anode spectra were analyzed with an equivalent circuit simulation. The conductance of the charge transfer was found to increase with current density up to a point where a raising limitation process of the complex methanol oxidation dominates, which is not a bottleneck at low current density. Further, an increase of the double layer capacitance with current density was observed. The diffusion resistance was calculated as an effective diffusion coefficient in the order of 10-10 m2 s-1; implying that the diffusion limitation is not the bulk diffusion in the backing layer. Finally, the degree of poisoning of the catalysts by carbon monoxide was measured as a pseudo inductive arc and decreases with increasing current.

  11. Sulfonated poly(ether ether ketone)/zirconium tricarboxybutylphosphonate composite proton-exchange membranes for direct methanol fuel cells

    Institute of Scientific and Technical Information of China (English)

    Qijun GAO; Mianyan HUANG; Yuxin WANG; Yuquan CAI; Li XU

    2008-01-01

    Sulfonated poly(ether ether ketone) (SPEEK) is a very promising alternative membrane material for direct methanol fuel cells. However, with a fairly high degree ofsulfonation (DS), SPEEK membranes can swell excessively and even dissolve at high temperature. This restricts mem-branes from working above a high tolerable temperature to get high proton conductivity. To deal with this contra-dictory situation, insolvable zirconium tricarboxybutyl-phosphonate (Zr(PBTC)) powder was employed to make a composite with SPEEK polymer in an attempt to improve temperature tolerance of the membranes. SPEEK/Zr(PBTC) composite membranes were obtained by casting a homogeneous mixture of Zr(PBTC) and SPEEK in N,N-dimethylacetamide on a glass plate and then evaporating the solvent at 60℃. Many characteristics were investigated, including thermal stability, liquid uptake, methanol permeability and proton conductivity. Results showed significant improvement not only in tem-perature tolerance, but also in methanol resistance of the SPEEK/Zr(PBTC) composite membranes. The mem-branes containing 30 wt-%~40 wt-% of Zr(PBTC) had their methanol permeability around 10-7 cm2·S-1 at room temperature to 80℃, which was one order of magnitudelower than that of Nafion 115. High proton conductivity of the composite membranes, however, could also be achieved from higher temperature applied. At 100% rela-tive humidity, above 90℃ the conductivity of the compo-site membrane containing 40 wt-% of Zr(PBTC) exceeded that of the Nafion 115 membrane and even reached a high value of 0.36 S·cm-1 at 160℃. Improved applicable tem-perature and high conductivity of the composite membrane indicated its promising application in DMFC operations at high temperature.

  12. Desenvolvimento de conjunto membrana-eletrodos para célula a combustível de metanol direto passiva Development of membrane electrode assembly for passive direct methanol fuel cell

    Directory of Open Access Journals (Sweden)

    Eli Carlos Lisboa Ferreira

    2010-01-01

    Full Text Available Direct methanol fuel cells (DMFCs without external pumps or other ancillary devices for fuel and oxidant supply are known as passive DMFCs and are potential candidates to replace lithium-ion batteries in powering portable electronic devices. This paper presents the results obtained from a membrane electrode assembly (MEA specifically designed for passive DMFCs. Appropriated electrocatalysts were prepared and the effect of their loadings was investigated. Two types of gas diffusion layers (GDL were also tested. The influence of the methanol concentration was analyzed in each case. The best MEA performance presented a maximum power density of 11.94 mW cm-2.

  13. Polypyrrole layered SPEES/TPA proton exchange membrane for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Neelakandan, S.; Kanagaraj, P. [PG & Research Department of Chemistry, Polymeric Materials Research Lab, Alagappa Government Arts College, Karaikudi 630003 (India); Sabarathinam, R.M. [Functional Material Division, Central Electrochemical Research Institute, Karaikudi 630006 (India); Nagendran, A., E-mail: nagimmm@yahoo.com [PG & Research Department of Chemistry, Polymeric Materials Research Lab, Alagappa Government Arts College, Karaikudi 630003 (India)

    2015-12-30

    Graphical abstract: - Highlights: • A series of Ppy layered SPEES/TPA composite membranes were prepared. • SPEES/TPA-Ppy hybrid membranes displayed efficient methanol resistance than Nafion 117. • SPEES/TPA-Ppy4 membrane exhibits highest relative selectivity of 2.86 × 104 S cm{sup 3} s. • Increasing Ppy layer on membrane surface reduces the leaching out of tungstophosphoric acid. - Abstract: Hybrid membranes based on sulfonated poly(1,4-phenylene ether ether sulfone) (SPEES)/tungstophosphoric acid (TPA) were prepared. SPEES/TPA membrane surfaces were modified with polypyrrole (Ppy) by in situ polymerization method to reduce the TPA leaching. The morphology and electrochemical property of the surface coated membranes were studied by SEM, AFM, water uptake, ion exchange capacity, proton conductivity, methanol permeability and tensile strength. The water uptake and the swelling ratio of the surface coated membranes decreased with increasing the Ppy layer. The surface roughness of the hybrid membrane was decreased with an increase in Ppy layer on the membrane surface. The methanol permeability of SPEES/TPA-Ppy4 hybrid membrane was significantly suppressed and found to be 2.1 × 10{sup −7} cm{sup 2} s{sup −1}, which is 1.9 times lower than pristine SPEES membrane. The SPEES/TPA-Ppy4 membrane exhibits highest relative selectivity (2.86 × 10{sup 4} S cm{sup −3} s) than the other membrane with low TPA leaching. The tensile strength of hybrid membranes was improved with the introduction of Ppy layer. Combining their lower swelling ratio, high thermal stability and selectivity, SPEES/TPA-Ppy4 membranes could be a promising material as PEM for DMFC applications.

  14. Direct Calculations of Current Drive with a Full Wave Code

    Science.gov (United States)

    Wright, John C.; Phillips, Cynthia K.

    1997-11-01

    We have developed a current drive package that evaluates the current driven by fast magnetosonic waves in arbitrary flux geometry. An expression for the quasilinear flux has been derived which accounts for coupling between modes in the spectrum of waves launched from the antenna. The field amplitudes are calculated in the full wave code, FISIC, and the current response function, \\chi, also known as the Spitzer function, is determined with Charles Karney's Fokker-Planck code, adj.f. Both codes have been modified to incorporate the same numerical equilibria. To model the effects of a trapped particle population, the bounce averaged equations for current and power are used, and the bounce averaged flux is calculated. The computer model is benchmarked against the homogenous equations for a high aspect ratio case in which the expected agreement is confirmed. Results from cases for TFTR, NSTX and CDX-U are contrasted with the predictions of the Ehst-Karney parameterization of current drive for circular equilibria. For theoretical background, please see the authors' archive of papers. (http://w3.pppl.gov/ ~jwright/Publications)

  15. Electrochemical Reduction of Carbon Dioxide to Methanol by Direct Injection of Electrons into Immobilized Enzymes on a Modified Electrode.

    Science.gov (United States)

    Schlager, Stefanie; Dumitru, Liviu Mihai; Haberbauer, Marianne; Fuchsbauer, Anita; Neugebauer, Helmut; Hiemetsberger, Daniela; Wagner, Annika; Portenkirchner, Engelbert; Sariciftci, Niyazi Serdar

    2016-03-21

    We present results for direct bio-electrocatalytic reduction of CO2 to C1 products using electrodes with immobilized enzymes. Enzymatic reduction reactions are well known from biological systems where CO2 is selectively reduced to formate, formaldehyde, or methanol at room temperature and ambient pressure. In the past, the use of such enzymatic reductions for CO2 was limited due to the necessity of a sacrificial co-enzyme, such as nicotinamide adenine dinucleotide (NADH), to supply electrons and the hydrogen equivalent. The method reported here in this paper operates without the co-enzyme NADH by directly injecting electrons from electrodes into immobilized enzymes. We demonstrate the immobilization of formate, formaldehyde, and alcohol dehydrogenases on one-and-the-same electrode for direct CO2 reduction. Carbon felt is used as working electrode material. An alginate-silicate hybrid gel matrix is used for the immobilization of the enzymes on the electrode. Generation of methanol is observed for the six-electron reduction with Faradaic efficiencies of around 10%. This method of immobilization of enzymes on electrodes offers the opportunity for electrochemical application of enzymatic electrodes to many reactions in which a substitution of the expensive sacrificial co-enzyme NADH is desired.

  16. Three dimensional graphene foam supported platinum-ruthenium bimetallic nanocatalysts for direct methanol and direct ethanol fuel cell applications

    Science.gov (United States)

    Kung, Chih-Chien; Lin, Po-Yuan; Xue, Yuhua; Akolkar, Rohan; Dai, Liming; Yu, Xiong; Liu, Chung-Chiun

    2014-06-01

    A novel composite material of hierarchically structured platinum-ruthenium (PtRu) nanoparticles grown on large surface area three dimensional graphene foam (3D GF) is reported. 3D GF was incorporated with PtRu bimetallic nanoparticles as an electrochemical nanocatalyst for methanol and ethanol oxidation. PtRu/3D GF nanocatalyst showed a higher tolerance to poisoning by CO and exhibited improved catalytic activity for both methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). Cyclic voltammetry (CV) results and long-term cycling stability tests demonstrated that GF provided a promising platform for the development of electrochemical nanocatalysts. Specifically, PtRu/3D GF nanocatalyst showed excellent catalytic activity toward MOR and EOR compared with PtRu/Graphene (Commercial graphene), PtRu/C (Vulcan XC-72R carbon), and PtRu alone. The crystal size of PtRu on 3D GF was reduced to 3.5 nm and its active surface area was enhanced to 186.2 m2 g-1. Consequently, the MOR and EOR rates were nearly doubled on PtRu/3D GF compared to those on PtRu/Graphene.

  17. Study of pyrolyzed hemin/C as non-platinum cathodic catalyst for direct methanol fuel cells

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Biological reduction of O2 to H2O justifies a serious look at heme as a potential O2 reduction reaction(ORR) catalyst for low temperature fuel cells.In this study,a novel non-platinum electrocatalyst for ORR was prepared through hemin,which is hydrochloride of heme,supported on Black Pearls 2000 carbon black(Hm-BP) pyrolyzed at 700-900℃ in Ar atmosphere.The physical and electrocatalytic properties of as-prepared catalysts were characterized by TGA,XRD,XPS,TEM,rotating disk electrode(RDE) and rotating ring disk electrode(RRDE).It has found that the catalyst treated at 750℃(Hm-BP-750) exhibits the best property among the Hm-BP catalysts prepared.The onset potential of ORR on the Hm-BP-750 at 30℃ was measured ca.0.90 V(vs.RHE) in 0.1 M H2SO4,and mass current density was reached 15.3 mA mg-1 at 0.75 V.It has revealed that O2 could be reduced directly to water in a 4e process between 0.9 and 0.83V,and the yield of H2O2 was 0-18% in the potential range of 0.83-0.63 V.This methanol-tolerant catalyst also presents excellent stability in medium-term test of direct methanol fuel cell at 80℃.

  18. Two-phase flow in anode flow field of a small direct methanol fuel cell in different gravities

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    An in-situ visualization of two-phase flow inside anode flow bed of a small liquid fed direct methanol fuel cells in normal and reduced gravity has been conducted in a drop tower.The anode flow bed con-sists of 11 parallel straight channels.The length,width and depth of single channel,which had rec-tangular cross section,are 48.0,2.5 and 2.0mm,respectively.The rib width was 2.0mm.The experi-mental results indicated that when the fuel cell orientation is vertical,two-phase flow pattern in anode channels can evolve from bubbly flow in normal gravity into slug flow in microgravity.The size of bub-bles in the reduced gravity is also bigger.In microgravity,the bubbles rising speed in vertical channels is obviously slower than that in normal gravity.When the fuel cell orientation is horizontal,the slug flow in the reduced gravity has almost the same characteristic with that in normal gravity.It implies that the effect of gravity on two-phase flow is small and the bubbles removal is governed by viscous drag.When the gas slugs or gas columns occupy channels,the performance of liquid fed direct methanol fuel cells is failing rapidly.It infers that in long-term microgravity,flow bed and operating condition should be optimized to avoid concentration polarization of fuel cells.

  19. Development of molecular and solid catalysts for the direct low-temperature oxidation of methane to methanol.

    Science.gov (United States)

    Palkovits, Regina; von Malotki, Christian; Baumgarten, Martin; Müllen, Klaus; Baltes, Christian; Antonietti, Markus; Kuhn, Pierre; Weber, Jens; Thomas, Arne; Schüth, Ferdi

    2010-02-22

    The direct low-temperature oxidation of methane to methanol is demonstrated on a highly active homogeneous molecular catalyst system and on heterogeneous molecular catalysts based on polymeric materials possessing ligand motifs within the material structure. The N-(2-methylpropyl)-4,5-diazacarbazolyl-dichloro-platinum(II) complex reaches significantly higher activity compared to the well-known Periana system and allows first conclusions on electronic and structural requirements for high catalytic activity in this reaction. Interestingly, comparable activities could be achieved utilizing a platinum modified poly(benzimidazole) material, which demonstrates for the first time a solid catalyst with superior activity compared to the Periana system. Although the material shows platinum leaching, improved activity and altered electronic properties, compared to the conventional Periana system, support the proposed conclusions on structure-activity relationships. In comparison, platinum modified triazine-based catalysts show lower catalytic activity, but rather stable platinum coordination even after several catalytic cycles. Based on these systems, further development of improved solid catalysts for the direct low-temperature oxidation of methane to methanol is feasible.

  20. Two-phase flow in anode flow field of a small direct methanol fuel cell in different gravities

    Institute of Scientific and Technical Information of China (English)

    GUO Hang; WU Feng; YE Fang; ZHAO JianFu; WAN ShiXin; L(U) CuiPing; MA ChongFang

    2009-01-01

    An in-situ visualization of two-phase flow inside anode flow bed of a small liquid fed direct methanol fuel cells in normal and reduced gravity has been conducted in a drop tower. The anode flow bed con-sists of 11 parallel straight channels. The length, width and depth of single channel, which had rec-tangular cross section, are 48.0, 2.5 and 2.0 mm, respectively. The rib width was 2.0 ram. The experi-mental results indicated that when the fuel cell orientation is vertical, two-phase flow pattern in anode channels can evolve from bubbly flow in normal gravity into slug flow in microgravity. The size of bub-bles in the reduced gravity is also bigger. In microgravity, the bubbles rising speed in vertical channels is obviously slower than that in normal gravity. When the fuel cell orientation is horizontal, the slug flow in the reduced gravity has almost the same characteristic with that in normal gravity. It implies that the effect of gravity on two-phase flow is small and the bubbles removal is governed by viscous drag. When the gas slugs or gas columns occupy channels, the performance of liquid fed direct methanol fuel cells is failing rapidly. It infers that in long-term microgravity, flow bed and operating condition should be optimized to avoid concentration polarization of fuel cells.

  1. The influence of methanol on the chemical state of PtRu anodes in a high-temperature direct methanol fuel cell studied in situ by synchrotron-based near-ambient pressure x-ray photoelectron spectroscopy

    Science.gov (United States)

    Saveleva, Viktoriia A.; Daletou, Maria K.; Savinova, Elena R.

    2017-01-01

    Synchrotron radiation-based near-ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) has recently become a powerful tool for the investigation of interfacial phenomena in electrochemical power sources such as batteries and fuel cells. Here we present an in situ NAP-XPS study of the anode of a high-temperature direct methanol fuel cell with a phosphoric acid-doped hydrocarbon membrane, which reveals an enhanced flooding of the Pt3Ru anode with phosphoric acid in the presence of methanol. An analysis of the electrode surface composition depending on the cell voltage and on the presence of methanol reveals the strong influence of the latter on the extent of Pt oxidation and on the transformation of Ru into Ru (IV) hydroxide.

  2. Characterization of direct methanol fuel cell (DMFC) applications with H{sub 2}SO{sub 4} modified chitosan membrane

    Energy Technology Data Exchange (ETDEWEB)

    Osifo, Peter O.; Masala, Aluwani [Department of Chemical Engineering, Vaal University of Technology, Andries Potgieter Bolevald, P/Bag X021, Vanderbijlpark 1900, Gauteng (South Africa)

    2010-08-01

    Chitosan (Chs) flakes were prepared from chitin materials that were extracted from the exoskeleton of Cape rock lobsters in South Africa. The Chs flakes were prepared into membranes and the Chs membranes were modified by cross-linking with H{sub 2}SO{sub 4}. The cross-linked Chs membranes were characterized for the application in direct methanol fuel cells. The Chs membrane characteristics such as water uptake, thermal stability, proton resistance and methanol permeability were compared to that of high performance conventional Nafion 117 membranes. Under the temperature range studied 20-60 C, the membrane water uptake for Chs was found to be higher than that of Nafion. Thermal analysis revealed that Chs membranes could withstand temperature as high as 230 C whereas Nafion 117 membranes were stable to 320 C under nitrogen. Nafion 117 membranes were found to exhibit high proton resistance of 284 s cm{sup -1} than Chs membranes of 204 s cm{sup -1}. The proton fluxes across the membranes were 2.73 mol cm{sup -2} s{sup -1} for Chs- and 1.12 mol cm{sup -2} s{sup -1} Nafion membranes. Methanol (MeOH) permeability through Chs membrane was less, 1.4 x 10{sup -6} cm{sup 2} s{sup -1} for Chs membranes and 3.9 x 10{sup -6} cm{sup 2} s{sup -1} for Nafion 117 membranes at 20 C. Chs and Nafion membranes were fabricated into membrane electrode assemblies (MAE) and their performances measure in a free-breathing commercial single cell DMFC. The Nafion membranes showed a better performance as the power density determined for Nafion membranes of 0.0075 W cm{sup -2} was 2.7 times higher than in the case of Chs MEA. (author)

  3. Novel manufacturing process for direct methanol fuel cells (DMFC) by defined layer structures; Neuartiges Herstellungsverfahren fuer Direkt-Methanol-Brennstoffzellen (DMFC) durch definierte Schichtstrukturen

    Energy Technology Data Exchange (ETDEWEB)

    Frey, Thomas

    2007-07-17

    A novel method to prepare membrane electrode assemblies (MEA) for direct methanol fuel cells (DMFC) by a layer-upon-layer fabrication onto a porous substrate is presented. The novel preparation technique is based on a single method for the fabrication of the whole MEA, e.g. spraying one functional layer onto the other, and therefore simplifies its preparation considerably. It also permits new fuel cell designs with in-plane serial connection of single cells. The new concept offers high flexibility in the choice of cell geometry as well as superior control of the structural parameters. Layer thickness, composition, catalyst and ionomer loadings can easily be varied and adapted. Cells fabricated with the new concept are especially suited for low power micro fuel cells operated at ambient conditions. In this work, process parameters enabling such a layer-upon-layer MEA preparation have been developed. Advanced catalyst inks and electrolyte solutions were formulated as precursors for each functional layer. Nafion {sup registered} as well as polyaryl-based polymers were investigated for the fabrication of dense electrolyte layers. Catalyst layers were prepared from inks containing Pt and PtRu-black catalysts which were suspended in suitable solvents with diluted proton-conducting electrolytes. The critical parameters for the layer build-up were identified and optimized afterwards. Various candidate materials for the porous substrate were characterized and selected for further investigation. Experiments and calculation models led to a concept and an advanced design for a serially connected multi-cells unit on the substrate. The inplane conductivity of the electrodes turned out to be the critical parameter resulting in high ohmic losses especially when the electrodes were applied on non-conductive substrates. Various conductive coatings were tested to selectively increase the conductivity of non-conductive substrates, which are prerequisite for serial connection. Only

  4. Hybridization and control of a mobile direct methanol fuel cell system; Hybridisierung und Regelung eines mobilen Direktmethanol-Brennstoffzellen-Systems

    Energy Technology Data Exchange (ETDEWEB)

    Wilhelm, Joerg Christoph

    2010-07-01

    Direct methanol fuel cells (DMFCs) are characterized by the fact that they directly convert the chemical energy of the liquid fuel methanol into electrical energy. Methanol has a high energy density and can be stored relatively easily. Due to these advantages, direct methanol fuel cell systems are suitable, for example, as a battery replacement for light-traction applications in the kW class. Since refuelling is much faster than recharging a battery, almost interruption-free operation is possible. The aim of this thesis is therefore to develop a direct methanol fuel cell system for light-traction applications. The systems technology development and characterization of a mobile direct methanol fuel cell system is initially examined in general and then applied to the example of a horizontal order picker, a type of forklift truck. A hybridization and control concept is developed for this type of truck. The procedure is structured into the theoretical characterization of the application, the development of theoretical concepts and a concluding systems analysis using data from the test stand and simulations. The characteristic driving cycle of the application results from the characterization. The concept development is based on key data such as maximum peak power during acceleration and braking as well as average power. The two-stage theoretical development of a hybridization concept is based on a pure fuel cell vehicle. A systems analysis of all possible concepts with respect to the criteria of fuel cell power, total system efficiency and dynamic fuel cell loading eventually leads to the preferred concept of indirect coupling. A cascade controller with map control, the control concept developed for this purpose, keeps the energy storage unit at a constant state of charge and provides for the fuel cell aging protection as well as aging detection. The driving cycle, operational states of the vehicle and the efficiencies of the individual components play a decisive role

  5. Controlled synthesis of Pt/CS/PW12-GNs composite as an anodic electrocatalyst for direct methanol fuel cells

    Science.gov (United States)

    Li, Zhongshui; Lei, Fengling; Ye, Lingting; Zhang, Xiaofeng; Lin, Shen

    2015-04-01

    Controlled assembly in aqueous solution was used to synthesize the well-organized Pt/CS/PW12-GNs composite. By the aid of linear cationic polysaccharide chitosan, 2-D distribution worm-like Pt nanoparticles with their length and width of 15-20 and 3-4 nm, respectively, were formed on the surface of CS/PW12-GNs using HCOOH as a reducing agent at room temperature. The introduction of CS leads to well dispersion of worm-like Pt nanoparticles, the electroactivity of H3PW12O40 (PW12) alleviates CO poisoning toward Pt particles, and graphene nanosheets (GNs) ensure excellent electrical conductivity of the composites. The combined action among different components results in significantly enhanced catalytic activity of Pt/CS/PW12-GNs toward methanol oxidation and better tolerance of CO. The as-synthesized Pt/CS/PW12-GNs exhibit the forward peak current density of 445 mA mg-1, which is much higher than that (220 mA mg-1) for Pt/C-JM (the commercially available Johnson Matthey Hispec4000 catalyst, simplified as Pt/C-JM) and some recently reported Pt/graphene-based nanomaterials. The construction of 2-D distribution worm-like Pt nanoparticles and facile wet chemical synthesis strategy provide a promising way to develop superior performance electrocatalysts for direct methanol fuel cells applications.

  6. Controlled synthesis of Pt/CS/PW{sub 12}-GNs composite as an anodic electrocatalyst for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhongshui; Lei, Fengling; Ye, Lingting; Zhang, Xiaofeng; Lin, Shen, E-mail: shenlin@fjnu.edu.cn [Fujian Normal University, College of Chemistry & Chemical Engineering (China)

    2015-04-15

    Controlled assembly in aqueous solution was used to synthesize the well-organized Pt/CS/PW{sub 12}-GNs composite. By the aid of linear cationic polysaccharide chitosan, 2-D distribution worm-like Pt nanoparticles with their length and width of 15–20 and 3–4 nm, respectively, were formed on the surface of CS/PW{sub 12}-GNs using HCOOH as a reducing agent at room temperature. The introduction of CS leads to well dispersion of worm-like Pt nanoparticles, the electroactivity of H{sub 3}PW{sub 12}O{sub 40} (PW{sub 12}) alleviates CO poisoning toward Pt particles, and graphene nanosheets (GNs) ensure excellent electrical conductivity of the composites. The combined action among different components results in significantly enhanced catalytic activity of Pt/CS/PW{sub 12}-GNs toward methanol oxidation and better tolerance of CO. The as-synthesized Pt/CS/PW{sub 12}-GNs exhibit the forward peak current density of 445 mA mg{sup −1}, which is much higher than that (220 mA mg{sup −1}) for Pt/C-JM (the commercially available Johnson Matthey Hispec4000 catalyst, simplified as Pt/C-JM) and some recently reported Pt/graphene-based nanomaterials. The construction of 2-D distribution worm-like Pt nanoparticles and facile wet chemical synthesis strategy provide a promising way to develop superior performance electrocatalysts for direct methanol fuel cells applications.

  7. A novel Pt/Cr/Ru/C cathode catalyst for direct methanol fuel cells (DMFC) with simultaneous methanol tolerance and oxygen promotion

    Energy Technology Data Exchange (ETDEWEB)

    Perez, G.; Zinola, C.F. [Laboratorio de Electroquimica Fundamental, Facultad de Ciencias, Universidad de la Republica, Igua 4225, C.P. 11400, Montevideo (Uruguay); Pastor, E. [Departamento de Quimica Fisica, Facultad de Quimica, Universidad de La Laguna, Astrofisico F. Sanchez s/n, 38071 La Laguna, Tenerife (Spain)

    2009-12-15

    New carbon supported electrocatalysts Pt/Cr/Ru with distinct compositions and preparation methods were studied with the help of different electrochemical and spectroscopic techniques. The purposes of obtaining these catalysts lie on their possibilities towards methanol/oxygen fuel cells. In this sense, the oxygen reduction reaction and methanol oxidation reaction were analyzed using stationary and fluid dynamic methodologies. Pt{sub 7.8}/Ru{sub 1.3}/Cr{sub 0.5} and Pt{sub 8.0}/Ru{sub 2.0}/Cr{sub 0.1} were the most interesting prepared substrates, on which the first one shows the best catalytic properties towards methanol oxidation and the second the finest performance towards oxygen reduction reaction. Reaction orders with respect to oxygen for the oxygen reduction reaction were obtained being equal to 1/2 at potentials lower than 0.80 V for both catalysts. Polarization curves run for this reaction depicted two Tafel slopes, i.e. 0.09 V dec{sup -1} above 0.8 V and 0.20 V dec{sup -1} below 0.8 V for both catalysts. An analysis of the most likely mechanism for the oxygen reduction was proposed on the base of those reaction orders and Tafel slopes. (author)

  8. Effect of precursor nature on the performance of palladium-cobalt electrocatalysts for direct methanol fuel cells

    Science.gov (United States)

    Serov, Alexey; Nedoseykina, Tatyana; Shvachko, Oleg; Kwak, Chan

    The performance of platinum-free palladium-cobalt catalysts in oxygen reduction was investigated for a direct methanol fuel cell. The dependence of catalytic activity on precursor nature was determined for two classes of precursors; namely, palladium chloride and palladium nitrate. The nitrate precursor exhibits much higher catalytic performance than the chloride precursor. X-ray absorption fine structure (XAFS) spectra indicate that the structure of palladium catalyst prepared from nitrate is much closer to Pd 3Co structure that can explain high catalytic activity. The MEA prepared from the nitrate catalyst achieved the peak power density of 125 mW cm -2, which is much higher than 19 mW cm -2 measured on the cell prepared from the chloride catalyst.

  9. The Fabrication of Flow Field Plates for Direct Methanol Fuel Cell Using Lithography and Radio Frequency Sputtering.

    Science.gov (United States)

    Chang, Ho; Kao, Mu-Jung; Chen, Chih-Hao; Cho, Kun-Ching; Hsu, Chun-Yao; Chen, Zhi-Lun

    2015-08-01

    This study uses lithography to etch flow fields on a single side of a printed circuit board (PCB) and combines a flow field plate with a collector plate to make innovative anode flow field plates and cathode flow field plates for a direct methanol fuel cell (DMFC). TiO2 thin film is also sputtered on the anode flow field plate using radio frequency (RF) sputtering. The experimental results show that the prepared DMFC has a better maximum power density of 11.928 mW/cm2. Furthermore, when a TiO2 thin film is sputtered on the flow field plate of the assembled DMFC, the maximum power density is 14.426 mW/cm2, which is actually 21% more than that for a DMFC with no TiO2 thin film coated on the flow field plate.

  10. Investigation of methanol oxidation on a highly active and stable Pt–Sn electrocatalyst supported on carbon–polyaniline composite for application in a passive direct methanol fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Amani, Mitra [Department of Chemical Engineering, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of); Kazemeini, Mohammad [Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Hamedanian, Mahboobeh [Department of Chemistry, Faculty of Science, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of); Pahlavanzadeh, Hassan [Department of Chemical Engineering, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of); Gharibi, Hussein, E-mail: h.gharibi@utah.edu [Department of Chemistry, Faculty of Science, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of); Department of Material Science & Engineering, 122 S Campus Drive, University of Utah, Salt Lake City, UT 84112 (United States)

    2015-08-15

    Highlights: • PtSn/C-PANI performed superior in the MOR compared with a commercial PtRu/C. • Catalytic activity of PtRu/C was highly reduced during the accelerated durability test. • Anode of the PtSn/C-PANI in a passive DMFC lowered methanol crossover by 30%. - Abstract: Polyaniline fiber (PANI) was synthesized and utilized to fabricate a vulcan–polyaniline (C-PANI) composite. Pt/C-PANI and PtSn/C-PANI electro-catalysts with different Pt:Sn atomic ratios were prepared by the impregnation method. These electro-catalysts, along with commercial PtRu/C (Electrochem), were characterized with respect to their structural and electrochemical properties in methanol oxidation reaction (MOR). PtSn(70:30)/C-PANI showed excellent performance in MOR, the obtained maximum current density being about 40% and 50% higher than that for PtRu/C and Pt/C-PANI, respectively. It was also found that the CO tolerance and stability of PtSn(70:30)/C-PANI was considerably higher than that of PtRu/C. Finally, the performance of these two materials was compared in a passive direct methanol fuel cell (DMFC). The DMFC test results demonstrated that the membrane electrode assembly (MEA) prepared using PtSn(70:30)/C-PANI anode catalyst performed more satisfactorily in terms of maximum power density and lower methanol crossover.

  11. Characterization of an anionic-exchange membranes for direct methanol alkaline fuel cells

    CSIR Research Space (South Africa)

    Abuin, GC

    2010-06-01

    Full Text Available T (PICT 35403), and Consejo Nacional de Investigaciones Cientı´ficas y Te´cn- icas (PID 5977) for financial support. MM and PN thanks CSIR (MSM) for support. HRC is a member of Consejo Nacional de Investigaciones Cientı´ficas y Te´cnicas (CONICET). EF...

  12. Covalent-ionically cross-linked polyetheretherketone proton exchange membrane for direct methanol fuel cell

    CSIR Research Space (South Africa)

    Luo, H

    2010-08-01

    Full Text Available Polymers, BASF Aktiengesellshaft, Ludwigshafen Germany, 2004, p. 5. [15] P.D. Beattie, F.P. Orfino, V.I. Basura, K. Zychowska, J. Ding, C. Chuy, J. Schmeisser and S. Holdcroft, Journal of Electroanalytical Chemistry, 503 (2001) 45. [16] K. Ramya and K...

  13. A review on durability issues and restoration techniques in long-term operations of direct methanol fuel cells

    Science.gov (United States)

    Mehmood, Asad; Scibioh, M. Aulice; Prabhuram, Joghee; An, Myung-Gi; Ha, Heung Yong

    2015-11-01

    Direct methanol fuel cells (DMFCs) remain attractive among advanced energy conversion technologies due to their high energy density and simple system configuration. Although they made an early market entry but failed to attain a large-scale commercialization mainly because of their inferior performance sustainment in lifetime operations and high production costs. There have been lots of R&D efforts made to upgrade the long-term durability of DMFCs to a commercially acceptable standard. These rigorous efforts have been useful in gaining insights about various degradation mechanisms and their origins. This review first briefly describes the recent progress in lifetime enhancement of DMFC technology reported by various groups in academia and industry. Then, it is followed by comprehensive discussions on the major performance degradation routes and associated physico-chemical origins, and influence of operational parameters, together with the methods which have been employed to alleviate and restore the performance losses. Finally, a brief summary of the presented literature survey is provided in conjunction with some possible future research directions.

  14. Direct synthesis of dimethyl carbonate from CO2 and methanol over CeO2 catalysts of different morphologies

    Indian Academy of Sciences (India)

    UNNIKRISHNAN P; SRINIVAS DARBHA

    2016-06-01

    The direct synthesis of dimethyl carbonate (DMC) from carbon dioxide CO2 and methanol is an attractive approach towards conversion of the greenhouse gas - CO2 into value-added chemicals and fuels.Ceria CeO2 catalyzes this reaction. But the conversion efficiency of CeO2 is enhanced when the byproductwater in the reaction medium is separated by employing trapping agents like 2-cyanopyridine (2-CP). In thiswork, the influence of morphology of CeO2 on the direct synthesis of DMC in presence of 2-CP is reported.CeO2 catalysts of cube, rod, spindle and irregular morphology (Ce - C, Ce - R, Ce - S and Ce - N, respectively)were prepared, characterized and studied as catalysts in the said reaction conducted in a batch mode. Amongall, Ce - S shows superior catalytic performance with nearly 100 mol% of DMC selectivity. Catalytic activitycorrelates with the concentration of acid and base sites of medium strength as well as defect sites. Ce - S has anoptimum number of these active sites and thereby shows superior catalytic performance.

  15. Short term changes in methanol emission and pectin methylesterase activity are not directly affected by light in Lycopersicon esculentum

    Science.gov (United States)

    Oikawa, P. Y.; Li, L.; Timko, M. P.; Mak, J. E.; Lerdau, M. T.

    2011-04-01

    Plants are an important source of atmospheric methanol (MeOH), the second most abundant organic gas after methane. Factors regulating phytogenic MeOH production are not well constrained in current MeOH emission models. Previous studies have indicated that light may have a direct influence on MeOH production. As light is known to regulate cell wall expansion, it was predicted that light would stimulate MeOH production through the pectin methylesterase (PME) pathway. MeOH emissions normalized for stomatal conductance (gs) did not, however, increase with light over short time scales (20-30 min). After experimentally controlling for gs and temperature, no light activation of PME activity or MeOH emission was observed. The results clearly demonstrate that light does not directly influence short-term changes in MeOH production and emission. Our data suggest that substrate limitation may be important in regulating MeOH production over short time scales. Future investigation of the long-term impacts of light on MeOH production may increase understanding of MeOH emission dynamics at the seasonal time scale.

  16. Optimization of hydrothermal synthesis of H-ZSM-5 zeolite for dehydration of methanol to dimethyl ether using full factorial design

    Institute of Scientific and Technical Information of China (English)

    Samaneh Hosseini; Majid Taghizadeh; Ali Eliassi

    2012-01-01

    H-ZSM-5 zeolite was synthesized by hydrothermal method.The effects of different synthesis parameters,such as hydrothermal crystallization temperature (170-190 ℃) and Si/Al molar ratio (100-150),on the catalytic performance of the dehydration of methanol to dimethyl ether (DME) over the synthesized H-ZSM-5 zeolite were studied.The catalysts were characterized by N2 adsorption-desorption,XRD,NH3-TPD,TGA/DTA,and SEM techniques.The full factorial design of experiments was applied to the synthesis of H-ZSM-5 zeolite and the effects of synthesis conditions and their interaction on the yield of DME as the response variable were determined.Analysis of variance showed that two variables and their interaction significantly affected the response.According to the experimental results,the optimized catalyst prepared at 170 ℃ with the Si/Al molar ratio of 100 showed the best catalytic performance among the tested H-ZSM-5 zeolite.

  17. A high selectivity quaternized polysulfone membrane for alkaline direct methanol fuel cells

    CSIR Research Space (South Africa)

    Abuin, GC

    2015-04-01

    Full Text Available in the three-phase region with similar characteristics to that of the bulky membrane. Acknowledgments The authors acknowledge MINCyT / NRF Cooperation Program RSA-Argentina (Grant 67370), ANPCyT (PICT 2091), and Consejo Nacional de Investigaciones... Científicas y Técnicas (PIP 0095) for financial support. MM and PN thanks CSIR (MSM) for support. HRC is a member of Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). EAF thanks a fellowship by CONICET. References [1] G. Olah, A. A...

  18. Nafion titania nanotubes nanocomposite electrolytes for high-temperature direct methanol fuel cells

    CSIR Research Space (South Africa)

    Cele, NP

    2012-01-01

    Full Text Available ], and anode materials for batteries [4]. Titanium-dioxide-supported noble metal catalysts, such as gold [5], silver, or platinum [6, 7], are effective in many important processes, such as selective oxidation and hydrogenation and automobile engine exhaust... the tubes leading to agglomeration. This thermodynamic synthesis mechanism results in the formation of KTiO2(OH) due to the presence of K+. Figure 2(a) shows the FTIR spectra for TNTs that have been annealed at 300?C. The peaks corresponding...

  19. Acid-base blend membranes based on 2-amino-benzimidazole and sulfonated poly(ether ether ketone) for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yongzhu; Manthiram, Arumugam [Materials Science and Engineering Program, The University of Texas at Austin, Austin, TX 78712 (United States); Guiver, Michael D. [Institute for Chemical Process and Environmental Technology, National Research Council of (Canada)

    2007-05-15

    Direct methanol fuel cells (DMFC) are attractive for portable and automobile power needs, but their commercialization is hampered by high methanol permeability and the high cost of the currently used Nafion membrane. We report here a novel, low-cost blend membrane consisting of polysulfone-2-amide-benzimidazole (a basic polymer) and sulfonated poly(ether ether ketone) (an acidic polymer), which facilitates proton conduction through acid-base interactions while preserving excellent chemical and mechanical stabilities. The blend membrane exhibits performance in DMFC much higher than that of Nafion 115 and similar to that of Nafion 112, but with a remarkably superior long-term performance than Nafion 112 due to significantly reduced methanol crossover, enhancing the commercialization prospects of DMFC. (author)

  20. Molecular modeling of the morphology and transport properties of two direct methanol fuel cell membranes: phenylated sulfonated poly(ether ether ketone ketone) versus Nafion

    Energy Technology Data Exchange (ETDEWEB)

    Devanathan, Ramaswami; Idupulapati, Nagesh B.; Dupuis, Michel

    2012-08-14

    We have used molecular dynamics simulations to examine membrane morphology and the transport of water, methanol and hydronium in phenylated sulfonated poly ether ether ketone ketone (Ph-SPEEKK) and Nafion membranes at 360 K for a range of hydration levels. At comparable hydration levels, the pore diameter is smaller, the sulfonate groups are more closely packed, the hydronium ions are more strongly bound to sulfonate groups, and the diffusion of water and hydronium is slower in Ph-SPEEKK relative to the corresponding properties in Nafion. The aromatic carbon backbone of Ph-SPEEKK is less hydrophobic than the fluorocarbon backbone of Nafion. Water network percolation occurs at a hydration level ({lambda}) of {approx}8 H{sub 2}O/SO{sub 3}{sup -}. At {lambda} = 20, water, methanol and hydronium diffusion coefficients were 1.4 x 10{sup -5}, 0.6 x 10{sup -5} and 0.2 x 10{sup -5} cm{sup 2}/s, respectively. The pore network in Ph-SPEEKK evolves dynamically and develops wide pores for {lambda} > 20, which leads to a jump in methanol crossover and ion transport. This study demonstrates the potential of aromatic membranes as low-cost challengers to Nafion for direct methanol fuel cell applications and the need to develop innovative strategies to combat methanol crossover at high hydration levels.

  1. Study on two-phase countercurrent flow and transport phenomenon in PEM of a direct methanol fuel cell

    Institute of Scientific and Technical Information of China (English)

    WANG; Jiang; SHI; Mingheng

    2006-01-01

    Based on the requirement of water management for a direct methanol fuel cell, this paper analyzes qualitatively the mechanism of occurrence and development of a two-phase countercurrent flow with corresponding transport phenomenon in the PEM. A one-dimensional, steady state quantitative model of heat and mass transfer in internal volumetric ohmic heating porous media saturated by liquid and vapor phases is developed. The effects of capillarity, electro-osmotic drag and phase change are included. Two important formulas to calculate the theoretical length of two-phase zone δt and determine the critical criterion |-ω/γ|cr for dryout in PEM are deduced. By use of these two dimensionless parameters, dryout of PEM can be easily predicted. Theoretical temperature, pressure and saturation profiles within the two-phase region are obtained numerically, which can help to explore the performance of a DMFC operating in its ohmic polarization region. The simulation results can be used to determine the catalyst content of cathode catalyst layer and the corresponding optimal thickness of PEM.

  2. Efficient anodic and direct phenol-arene C,C cross-coupling: the benign role of water or methanol.

    Science.gov (United States)

    Kirste, Axel; Elsler, Bernd; Schnakenburg, Gregor; Waldvogel, Siegfried R

    2012-02-22

    C,C cross-coupling reactions for the synthesis of nonsymmetrical biaryls represent one of the most significant transformations in contemporary organic chemistry. A variety of useful synthetic methods have been developed in recent decades, since nonsymmetrical biaryls play an evident role in natural product synthesis, as ligand systems in homogeneous catalysis and materials science. Transformation of simple arenes by direct C,H activation belongs to the cutting-edge strategies for creating biaryls; in particular the 2-fold C,H activation is of significant interest. However, in most examples very costly noble metal catalysts, ligand systems, and significant amount of waste-producing oxidants are required. Electrochemical procedures are considered as inherently "green" methods, because only electrons are required and therefore, no reagent waste is produced. Here, we report a metal-free electrochemical method for cross-coupling between phenols and arenes using boron-doped diamond (BDD) anodes in fluorinated media. Our sustainable approach requires no leaving functionalities. Employing water or methanol as mediator represents the key improvement for achieving nonsymmetrical biaryls with superb selectivity and synthetic attractive yields.

  3. Direct methanol fuel cells: The effect of electrode fabrication procedure on MEAs structural properties and cell performance

    Science.gov (United States)

    Song, S. Q.; Liang, Z. X.; Zhou, W. J.; Sun, G. Q.; Xin, Q.; Stergiopoulos, V.; Tsiakaras, P.

    In the present paper, the effect of electrode preparation procedure on the structural properties of membrane electrode assembly (MEA) and consequently on the performance of direct methanol fuel cells (DMFCs) was investigated. Commercial PtRu black anode catalyst and Pt black cathode catalyst were characterized by XRD in their initial form and in their intermediate and final states after each step involved in catalyst-coated membrane electrode preparation procedure by a decal transfer method (DTM). XRD results demonstrated that the DTM process has a significant effect on the catalyst structural properties, especially on the particle size of Pt black cathode catalyst. It is also discussed that among all the steps involved in the electrode fabrication procedure, catalyst ink preparation and high temperature transfer process are key factors affecting the particle size of Pt black catalyst. Furthermore, it was found that the maximum power density of the single DMFC using a MEA fabricated by the DTM, when air is used as oxidant, is more than two times greater than that of the cell using conventionally prepared MEA, and more than three times greater when pure oxygen is used as oxidant. This could be attributed to the easier mass transportation due to the thinner catalyst layer and the better contact between the catalyst layer and the electrolyte membrane in the former case, even if, according to in situ CO stripping voltammetry results in the fuel cell anode environment, the surface composition of PtRu anode has been changed.

  4. Electrochemical impedance spectroscopy analysis of a thin polymer film-based micro-direct methanol fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Tobias; Weinmueller, Christian; Nabavi, Majid; Poulikakos, Dimos [Department of Mechanical and Process Engineering, Laboratory of Thermodynamics in Emerging Technologies, Institute of Energy Technology, ETH Zurich, CH-8092 Zurich (Switzerland)

    2010-11-15

    A single cell micro-direct methanol fuel cell (micro-DMFC) was investigated using electrochemical impedance spectroscopy. The electrodes consisted of thin, flexible polymer (SU8) film microchannel structures fabricated in-house using microfabrication techniques. AC impedance spectroscopy was used to separate contributions to the overall cell polarization from the anode, cathode and membrane. A clear distinction between the different electrochemical phenomena occurring in the micro-DMFC, especially the distinction between double layer charging and Faradaic reactions was shown. The effect of fuel flow rate, temperature, and anode flow channel structure on the impedance of the electrode reactions and membrane/electrode double layer charging were investigated. Analysis of impedance data revealed that the performance of the test cell was largely limited by the presence of intermediate carbon monoxide in the anode reaction. Higher temperatures increase cell performance by enabling intermediate CO to be oxidized at much higher rates. The results also revealed that serpentine anode flow microchannels show a lower tendency to intermediate CO coverage and a more stable cell behavior than parallel microchannels. (author)

  5. Measurement of the current distribution in a direct methanol fuel cell-Confirmation of parallel galvanic and electrolytic operation within one cell

    Science.gov (United States)

    Sauer, Dirk Uwe; Sanders, Tilman; Fricke, Birger; Baumhöfer, Thorsten; Wippermann, Klaus; Kulikovsky, Andrei A.; Schmitz, Heinz; Mergel, Jürgen

    Current production in fuel cells is typically unequally distributed along the cell surface due to inhomogeneous concentration of reactants and temperature. The inhomogeneities in fuel cells can result in reduced output power and accelerated ageing. To quantify the inhomogeneities a measurement system has been developed which allows measuring the local distribution of current and temperature in hydrogen and direct methanol fuel cells. With this system we are able to directly observe the coexistence of galvanic and electrolytic domains in a single channel direct methanol fuel cell (the electrolytic domain is the domain where electrolysis occurs in contrast to the galvanic domain where the fuel cell process takes place). The measurement device also allows for the measurement locally resolved impedance spectra.

  6. Platinum and palladium nano-structured catalysts for polymer electrolyte fuel cells and direct methanol fuel cells.

    Science.gov (United States)

    Long, Nguyen Viet; Thi, Cao Minh; Yong, Yang; Nogami, Masayuki; Ohtaki, Michitaka

    2013-07-01

    In this review, we present the synthesis and characterization of Pt, Pd, Pt based bimetallic and multi-metallic nanoparticles with mixture, alloy and core-shell structure for nano-catalysis, energy conversion, and fuel cells. Here, Pt and Pd nanoparticles with modified nanostructures can be controllably synthesized via chemistry and physics for their uses as electro-catalysts. The cheap base metal catalysts can be studied in the relationship of crystal structure, size, morphology, shape, and composition for new catalysts with low cost. Thus, Pt based alloy and core-shell catalysts can be prepared with the thin Pt and Pt-Pd shell, which are proposed in low and high temperature proton exchange membrane fuel cells (PEMFCs), and direct methanol fuel cells (DMFCs). We also present the survey of the preparation of Pt and Pd based catalysts for the better catalytic activity, high durability, and stability. The structural transformations, quantum-size effects, and characterization of Pt and Pd based catalysts in the size ranges of 30 nm (1-30 nm) are presented in electro-catalysis. In the size range of 10 nm (1-10 nm), the pure Pt catalyst shows very large surface area for electro-catalysis. To achieve homogeneous size distribution, the shaped synthesis of the polyhedral Pt nanoparticles is presented. The new concept of shaping specific shapes and morphologies in the entire nano-scale from nano to micro, such as polyhedral, cube, octahedra, tetrahedra, bar, rod, and others of the nanoparticles is proposed, especially for noble and cheap metals. The uniform Pt based nanosystems of surface structure, internal structure, shape, and morphology in the nanosized ranges are very crucial to next fuel cells. Finally, the modifications of Pt and Pd based catalysts of alloy, core-shell, and mixture structures lead to find high catalytic activity, durability, and stability for nano-catalysis, energy conversion, fuel cells, especially the next large-scale commercialization of next

  7. Proton-conducting Membranes Based on PVA-PAMPS Semi-interpenetrating Polymer Networks for Low Temperature Direct Methanol Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    Jinli Qiao; Tatsuhiro Okada

    2005-01-01

    @@ 1Introduction In direct methanol fuel cells (DMFCs) the methanol crossover from anode to cathode through the polymer electrolyte membrane is a major isue, because this not only causes loss of fuel, but also reduces the performance at the cathode due to the mixed reaction of methanol oxidation with oxygen reduction reaction. Membranes that show high proton conductivity, and at the same time, low methanol permeability are strongly desired but difficult to attain, because of trade-off relations between these parameters. We here report a new type of cost-effective polymer blend membranes based on chemically cross-linked poly(vinyl alcohol) (PVA)and 2-acrylamido-2-methyl-1-propanesulfonic acid (PAMPS) which is called semi-interpenetrating polymer networks (semi-IPNs). The membrane structure is finished by cross-linking the hydroxyl groups of poly (vinyl alchol) (PVA) main chain with acetal ring formation using glutaraldehyde (GA) cross-linker. For improving the flexibility of the membranes, we reported "binary chemcial cross-linking", "hydrophobicizer" and "stabilizer"effect[1-3], respectively, in our recent work.

  8. Direct methanol fuel cells: Pt-Ni/C binary electrocatalysts; Celulas a combutivel de metanol direto: eletrocatalisadores binarios de Pt-Ni/C

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, Jose Ricardo Cezar; Antolini, Ermete; Santos, Ana Maria dos; Gonzalez, Ernesto Rafael [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica], e-mail: salgado@iqsc.usp.br

    2004-07-01

    Direct methanol fuel cells use platinum alloys as more efficient catalysts than platinum. In the case of binary alloys, the second metal affects several properties of platinum, like the interatomic distance, the electronic density and the capacity of forming oxygenated species at lower potentials. In this work, Pt-Ni catalysts supported on high surface area carbon (Pt-Ni/C) were prepared and characterized, and tested as catalysts in the anode and the cathode in direct methanol fuel cells. In both cases the performance of the material was better than that of Pt/C, and comparing the two situations it was better when the material was used in the cathode. The improved performance in the cathode was attributed to the nickel that forms a true alloy with platinum, while the better performance in the anode was attributed to the presence of nickel oxides. (author)

  9. Microwave-assisted synthesis of high-loading, highly dispersed Pt/carbon aerogel catalyst for direct methanol fuel cell

    Indian Academy of Sciences (India)

    Zhijun Guo; Hong Zhu; Xinwei Zhang; Fanghui Wang; Yubao Guo; Yongsheng Wei

    2011-06-01

    A Pt supported on carbon aerogel catalyst has been synthesized by the microwave-assisted polyol process. The Pt supported on carbon aerogel catalyst was characterized by high resolution transmission electron microscopy and X-ray diffraction. The results show a uniform dispersion of spherical Pt nanoparticles 2.5–3.0 nm in diameter. Cyclic voltammetry and chronoamperometry were used to evaluate the electrocatalytic activity of the Pt/carbon aerogel catalyst for methanol oxidation at room temperature. The Pt/carbon aerogel catalyst shows higher electrochemical catalytic activity and stability for methanol oxidation than a commercial Pt/C catalyst of the same Pt loading.

  10. Layer-by-layer self-assembly of PDDA/PWA-Nafion composite membranes for direct methanol fuel cells.

    Science.gov (United States)

    Yang, Meng; Lu, Shanfu; Lu, Jinlin; Jiang, San Ping; Xiang, Yan

    2010-03-07

    A novel PDDA/PWA-Nafion composite electrolyte membrane with enhanced proton conductivity (sigma) to methanol permeability (P) ratio, sigma/P, was fabricated by layer-by-layer self-assembly of negatively charged water soluble PWA and positively charged polyelectrolyte PDDA.

  11. Fast Measurement of Methanol Concentration in Ionic Liquids by Potential Step Method

    Directory of Open Access Journals (Sweden)

    Michael L. Hainstock

    2015-01-01

    Full Text Available The development of direct methanol fuel cells required the attention to the electrolyte. A good electrolyte should not only be ionic conductive but also be crossover resistant. Ionic liquids could be a promising electrolyte for fuel cells. Monitoring methanol was critical in several locations in a direct methanol fuel cell. Conductivity could be used to monitor the methanol content in ionic liquids. The conductivity of 1-butyl-3-methylimidazolium tetrafluoroborate had a linear relationship with the methanol concentration. However, the conductivity was significantly affected by the moisture or water content in the ionic liquid. On the contrary, potential step could be used in sensing methanol in ionic liquids. This method was not affected by the water content. The sampling current at a properly selected sampling time was proportional to the concentration of methanol in 1-butyl-3-methylimidazolium tetrafluoroborate. The linearity still stood even when there was 2.4 M water present in the ionic liquid.

  12. Direct and Highly Selective Conversion of Synthesis Gas into Lower Olefins: Design of a Bifunctional Catalyst Combining Methanol Synthesis and Carbon-Carbon Coupling.

    Science.gov (United States)

    Cheng, Kang; Gu, Bang; Liu, Xiaoliang; Kang, Jincan; Zhang, Qinghong; Wang, Ye

    2016-04-01

    The direct synthesis of lower (C2 to C4) olefins, key building-block chemicals, from syngas (H2/CO), which can be derived from various nonpetroleum carbon resources, is highly attractive, but the selectivity for lower olefins is low because of the limitation of the Anderson-Schulz-Flory distribution. We report that the coupling of methanol-synthesis and methanol-to-olefins reactions with a bifunctional catalyst can realize the direct conversion of syngas to lower olefins with exceptionally high selectivity. We demonstrate that the choice of two active components and the integration manner of the components are crucial to lower olefin selectivity. The combination of a Zr-Zn binary oxide, which alone shows higher selectivity for methanol and dimethyl ether even at 673 K, and SAPO-34 with decreased acidity offers around 70% selectivity for C2-C4 olefins at about 10% CO conversion. The micro- to nanoscale proximity of the components favors the lower olefin selectivity.

  13. Effects of environmental factors on corrosion behaviors of metal-fiber porous components in a simulated direct methanol fuel cell environment

    Institute of Scientific and Technical Information of China (English)

    Wei Yuan; Bo Zhou; Yong Tang; Zhao-chun Zhang; Jun Deng

    2014-01-01

    To enable the use of metallic components in direct methanol fuel cells (DMFCs), issues related to corrosion resistance must be considered because of an acid environment induced by the solid electrolyte. In this study, we report the electrochemical behaviors of metal-fiber-based porous sintered components in a simulated corrosive environment of DMFCs. Three materials were evaluated:pure copper, AISI304, and AISI316L. The environmental factors and related mechanisms affecting the corrosion behaviors were analyzed. The results demonstrated that AISI316L exhibits the best performance. A higher SO42-concentration increases the risk of material corrosion, whereas an increase in methanol concentration inhibits corrosion. The morphological features of the corroded samples were also characterized in this study.

  14. Novel method for the synthesis of hydrophobic Pt-Ru nanoparticles and its application to preparing a Nafion-free anode for the direct methanol fuel cell.

    Science.gov (United States)

    Tu, Hung-Chi; Wang, Wen-Lin; Wan, Chi-Chao; Wang, Yung-Yun

    2006-08-17

    Pt-Ru alloy is a bimetallic catalyst most commonly used in the direct methanol fuel cell (DMFC). In this paper, a new process to synthesize an unsupported Pt-Ru colloid has been introduced. The characteristics of synthesized nanoparticles were identified by XRD, TEM/EDX, and SEM, and it shows that Ru atoms are incorporated into the Pt fcc structure and the well-dispersed particles (diameter approximately 4 nm) possess a Pt-rich feature. This catalyst shows a hydrophobic characteristic which can adsorb very well on the hydrophobic-treated carbon paper or carbon cloth without the need of Nafion. Accordingly, this method can avoid particle agglomeration, and the synthesized catalyst demonstrates strong adsorption with carbon paper. In addition, this colloid-type Nafion-free catalyst was measured via linear sweep voltammetry (LSV) and exhibited electrochemical activity for methanol oxidation comparable to the commercial one with Nafion binding.

  15. Formation and evaluation of semi-IPN of nafion 117 membrane for direct methanol fuel cell. 1. Crosslinked sulfonated polystyrene in the pores of nafion 117

    Science.gov (United States)

    Kundu, P. P.; Kim, Beom Taek; Ahn, Ji Eun; Han, Hak Soo; Shul, Yong Gun

    The in situ polymerization and crosslinking of sodium salt of sulfonated styrene in the pores of nafion 117 membrane has been studied for the evaluation of electrical performance of the resultant semi-IPN (semi-interpenetrating polymer network) membrane in direct methanol fuel cell (DMFC). The formation of semi-IPN is confirmed from the presence of aromatic characteristics peak in the FTIR spectra. Impedance results indicate that the semi-IPN sample with higher water uptake exhibits lower interfacial resistance compared to a sample with water uptake. This indicates that the semi-IPN formed in the pores of nafion 117 membrane has the ability to reduce methanol crossover by blocking the transportation. At higher temperatures (>110 °C) and lower current density (<25 mA cm -2), the electrical performance (power density) of a DMFC with a representative semi-IPN sample is observed to be higher than that with a nafion membrane.

  16. An in-situ nano-scale swelling-filling strategy to improve overall performance of Nafion membrane for direct methanol fuel cell application

    Science.gov (United States)

    Li, Jing; Fan, Kun; Cai, Weiwei; Ma, Liying; Xu, Guoxiao; Xu, Sen; Ma, Liang; Cheng, Hansong

    2016-11-01

    A novel in-situ nano-scale swelling-filling (SF) strategy is proposed to modify commercial Nafion membranes for performance enhancement of direct methanol fuel cells (DMFCs). A Nafion membrane was filled in-situ with proton conductive macromolecules (PCMs) in the swelling process of a Nafion membrane in a PCM solution. As a result, both proton conductivity and methanol-permeation resistivity of the SF-treated Naifion membrane was substantially improved with the selectivity nearly doubled compared to the original Nafion membrane. The mechanical strength of the optimal SF treated Nafion membrane was also enforced due to the strong interaction between the PCM fillers and the Nafion molecular chains. As a result, a DMFC equipped with the SF-treated membrane yielded a 33% higher maximum power density than that offered by the DMFC with the original Nafion membrane.

  17. Direct growth of NiCo2O4 nanostructures on conductive substrates with enhanced electrocatalytic activity and stability for methanol oxidation

    Science.gov (United States)

    Qian, Lei; Gu, Li; Yang, Li; Yuan, Hongyan; Xiao, Dan

    2013-07-01

    In this report, NiCo2O4 nanostructures with different morphologies were directly grown on conductive substrates (stainless steel and ITO) by a facile electrodeposition method in addition to a post-annealing process. The morphology changes on different conductive substrates are discussed in detail. The NiCo2O4 on stainless steel (SS) had a high surface area (119 m2 g-1) and was successfully used in the electrocatalytic oxidation of methanol. The electrocatalytic performance was investigated by cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS) measurements. Impressively, the NiCo2O4 showed much higher electrocatalytic activity, lower overpotential and greater stability compared to that of only NiO or Co3O4 synthesized by the same method. The higher electrocatalytic activity is due to the high electron conductivity, large surface area of NiCo2O4 and the fast ion/electron transport in the electrode and at the electrolyte-electrode interface. This is important for further development of high performance non-platinum electrocatalysts for application in direct methanol fuel cells.In this report, NiCo2O4 nanostructures with different morphologies were directly grown on conductive substrates (stainless steel and ITO) by a facile electrodeposition method in addition to a post-annealing process. The morphology changes on different conductive substrates are discussed in detail. The NiCo2O4 on stainless steel (SS) had a high surface area (119 m2 g-1) and was successfully used in the electrocatalytic oxidation of methanol. The electrocatalytic performance was investigated by cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS) measurements. Impressively, the NiCo2O4 showed much higher electrocatalytic activity, lower overpotential and greater stability compared to that of only NiO or Co3O4 synthesized by the same method. The higher electrocatalytic activity is due to the high electron conductivity

  18. CO tolerant PtRu-MoO{sub x} nanoparticles supported on carbon nanofibers for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Tsiouvaras, N.; Pena, M.A.; Fierro, J.L.G. [Instituto de Catalisis y Petroleoquimica, CSIC, Marie Curie 2, 28049 Madrid (Spain); Martinez-Huerta, M.V. [Instituto de Catalisis y Petroleoquimica, CSIC, Marie Curie 2, 28049 Madrid (Spain); Facultad de Quimicas, Universidad de La Laguna, Astrofisico Francisco Sanchez s/n, 38071, La Laguna, Tenerife (Spain); Moliner, R.; Lazaro, M.J. [Instituto de Carboquimica, CSIC, Miguel Luesma Castan 4, 50018 Zaragoza (Spain); Rodriguez, J.L.; Pastor, E. [Facultad de Quimicas, Universidad de La Laguna, Astrofisico Francisco Sanchez s/n, 38071, La Laguna, Tenerife (Spain)

    2009-01-15

    Novel nanostructured catalysts based on PtRu-MoO{sub x} nanoparticles supported on carbon nanofibers have been investigated for CO and methanol electrooxidation. Carbon nanofibers are prepared by thermocatalytic decomposition of methane (NF), and functionalized with HNO{sub 3} (NF.F). Electrocatalysts are obtained using a two-step procedure: (1) Pt and Ru are incorporated on the carbon substrates (Vulcan XC 72R, NF and NF.F), and (2) Mo is loaded on the PtRu/C samples. Differential electrochemical mass spectrometry (DEMS) analyses establish that the incorporation of Mo increases significantly the CO tolerance than respective binary counterparts. The nature of the carbon support affects considerably the stabilization of MoO{sub x} nanoparticles and also the performance in methanol electrooxidation. Accordingly, a significant increase of methanol oxidation is obtained in PtRu-MoO{sub x} nanoparticles supported on non-functionalized carbon nanofiber, in parallel with a large reduction of the Pt amount in comparison with binary counterparts and commercial catalyst. (author)

  19. Development of a direct methanol fuel cell system for the power segment below 5 kW; Entwicklung eines Direkt-Methanol-Brennstoffzellensystems der Leistungsklasse kleiner 5 kW

    Energy Technology Data Exchange (ETDEWEB)

    Noelke, M.

    2006-10-20

    The attractiveness of electrical conversion of liquid methanol in a fuel cell is defined by its simple storage and high energy density. Therefore, direct-methanol fuel cell (DMFC) qualifies for applications in portable systems and mobile application in the kW-class. The goal of this work is to develop and demonstrate an improved and optimized peripheral DMFC system compared to the current level of technology. The selected mobile application is the retrofit of the energy supply of a ''Scooter'' with a fuel cell system. The required size reduction and the simplification of the DMFC system are realized by an integrated concept, which combines ideally the peripheral system and the fuel cell. A profound analysis of the stack and the peripheral components is a prerequisite for an optimized design. A detailed modelling and understanding of the stack behaviour establish the starting point of this work. The influence of the most important operating parameters like stack temperature, cell voltage, current density, air ratio and methanol concentration is captured accurately by the developed model and validated by experimental data. This shapes the frame work of the following system design approach. For this the clearly defined task of the peripheral system are investigated individually for alternatives and the best option is selected for the final solution. For selecting the right pumps and blowers available products and prototypes are characterized and checked for the system requirements. The investigation and the modelling of the exhaust gas condenser lead to an optimized component design for the ''Scooter'' DMFC design. Additionally, the integration of the anode loop is accomplished consisting of the supply lines, the circulating pump, the gas separator and the exhaust line. The direct coupling of the fuel cell with a lithium-ion battery as an option for electrical conditioning is investigated. In the system modelling the influence

  20. Application of Mössbauer spectroscopy in industrial heterogeneous catalysis: effect of oxidant on FePO{sub 4} material phase transformations in direct methanol synthesis from methane

    Energy Technology Data Exchange (ETDEWEB)

    Dasireddy, Venkata D. B. C., E-mail: dasireddy@ki.si [National Institute of Chemistry, Department of Catalysis and Chemical Reaction Engineering (Slovenia); Khan, Faiza B. [Energy Technology (South Africa); Hanzel, Darko [Jozef Stefan Institute (Slovenia); Bharuth-Ram, Krish [Durban University of Technology, Physics Department (South Africa); Likozar, Blaž [National Institute of Chemistry, Department of Catalysis and Chemical Reaction Engineering (Slovenia)

    2017-11-15

    The effect of the FePO{sub 4} material phase transformation in the direct selective oxidation of methane to methanol was studied using various oxidants, i.e. O{sub 2}, H{sub 2}O and N{sub 2}O. The phases of the heterogeneous catalyst applied, before and after the reactions, were characterized by M¨ossbauer spectroscopy. The main reaction products were methanol, carbon monoxide and carbon dioxide, whereas formaldehyde was produced in rather minute amounts. The Mössbauer spectra showed the change of the initial catalyst material, FePO{sub 4} (tridymite-like phase (tdm)), to the reduced metal form, iron(II) pyrophosphate, Fe{sub 2}P{sub 2}O{sub 7}, and thereafter, the material phase change was governed by the oxidation with individual oxidizing species.Mössbauer spectroscopy measurements applied along with X-ray diffraction (XRD) studies on fresh, reduced and spent catalytic materials demonstrated a transformation of the catalyst to a mixture of phases which depended on operating process conditions. Generally, activity was low and should be a subject of further material optimization and engineering, while the selectivity towards methanol at low temperatures applied was adequate. The proceeding redox mechanism should thus play a key role in catalytic material design, while the advantage of iron-based heterogeneous catalysts primarily lies in them being comparably inexpensive and comprising non-critical raw materials only.

  1. Direct recovery of infectious Pestivirus from a full-length RT-PCR amplicon

    DEFF Research Database (Denmark)

    Rasmussen, Thomas Bruun; Reimann, Ilona; Hoffmann, Bernd;

    2008-01-01

    , and the resulting RNA transcripts were electroporated into ovine cells. Infectious virus was obtained after one cell culture passage. The rescued viruses had a phenotype similar to the parental Border Disease virus strain. Therefore, direct generation of infectious pestiviruses from full-length RT-PCR cDNA products...

  2. Chemically Synthesised Pt Particles on Surface Oxidized Carbon Nanotubes as an Effective Catalyst for Direct Methanol Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    Mohammad; yari; Sajjad; Sadaghat; Sharehjini

    2007-01-01

    1 Results The synthesis, physical characterization and electrochemical analysis of Pt particles prepared using the surface oxidized carbon nanotubes prepared by chemically anchoring Pt onto the surface of the CNTs with 2.0 mol/L HNO3 by refluxing for 10 h to introduce surface functional groups.The particles of Pt are synthesized by reduction with sodium borohydride of H2PtCl6. The electro-oxidation of liquid methanol of this catalyst as a thin layer on glassy carbon electrode is investigated at room te...

  3. Development of a Direct Fabrication Technique for Full-Shell X-Ray Optics

    Science.gov (United States)

    Gubarev, M.; Kolodziejczak, J. K.; Griffith, C.; Roche, J.; Smith, W. S.; Kester, T.; Atkins, C.; Arnold, W.; Ramsey, B.

    2016-01-01

    Future astrophysical missions will require fabrication technology capable of producing high angular resolution x-ray optics. A full-shell direct fabrication approach using modern robotic polishing machines has the potential for producing high resolution, light-weight and affordable x-ray mirrors that can be nested to produce large collecting area. This approach to mirror fabrication, based on the use of the metal substrates coated with nickel phosphorous alloy, is being pursued at MSFC. The design of the polishing fixtures for the direct fabrication, the surface figure metrology techniques used and the results of the polishing experiments are presented.

  4. Ion conductivity and mass spectrometry of methanol diffusion and electroosmotic drag on proton-conducting membranes for the Direct Methanol Fuel Cell (DMFC); Ionische Leitfaehigkeit und massenspektrometrische Bestimmung der Methanol-Diffusion und des 'Electroosmotic Drag' an protonenleitenden Membranen fuer die Direkt-Methanol-Brennstoffzelle (DMFC)

    Energy Technology Data Exchange (ETDEWEB)

    Oeztuerk, N.

    2001-07-01

    The methanol permeability of the nafion membrane is one reason why the DMFC is not marketable as yet. As a result of diffusion, permeation and electroosmotic drag, methanol is transferred to the kation side where it will reduce the fuel cell performance. Research is going on world-wide to develop new materials that will prevent methanol crossover. The report describes the development of a measuring cell that will provide the necessary information on diffusion, permeation, electroosmotic drag and conductivity. [German] Ein wesentlicher Grund, der die Einfuehrung der DMFC noch verhindert, ist die Methanoldurchlaessigkeit der Nafion-Membran. Durch Diffusion und Permeation und durch den Electroosmotic Drag gelangt Methanol auf die Kathodenseite und fuehrt dann zu einem Leistungsabfall der Brennstoffzelle. Daher werden weltweit neue Materialien entwickelt, die bei guter lonenleitfaehigkeit den Methanol-crossover unterdruecken. Zur Beurteilung und Weiterentwicklung der neuen Materialien werden Informationen zur Diffusion, Permeation, zum Electroosmotic Drag und zur Leitfaehigkeit benoetigt. Um diese Parameter schnell und einfach zu bestimmen, wurde im Rahmen der vorliegenden Arbeit eine Messzelle weiter entwickelt. Diese Messzelle erlaubt die schnelle Bestimmung aller vier wichtigen Parameter. (orig.)

  5. An ecosystem-scale perspective of the net land methanol flux: synthesis of micrometeorological flux measurements

    Directory of Open Access Journals (Sweden)

    G. Wohlfahrt

    2015-01-01

    Full Text Available Methanol is the second most abundant volatile organic compound in the troposphere and plays a significant role in atmospheric chemistry. While there is consensus about the dominant role of living plants as the major source and the reaction with OH as the major sink of methanol, global methanol budgets diverge considerably in terms of source/sink estimates reflecting uncertainties in the approaches used to model, and the empirical data used to separately constrain these terms. Here we compiled micrometeorological methanol flux data from eight different study sites and reviewed the corresponding literature in order to provide a first cross-site synthesis of the terrestrial ecosystem-scale methanol exchange and present an independent data-driven view of the land–atmosphere methanol exchange. Our study shows that the controls of plant growth on the production, and thus the methanol emission magnitude, and stomatal conductance on the hourly methanol emission variability, established at the leaf level, hold across sites at the ecosystem-level. Unequivocal evidence for bi-directional methanol exchange at the ecosystem scale is presented. Deposition, which at some sites even exceeds methanol emissions, represents an emerging feature of ecosystem-scale measurements and is likely related to environmental factors favouring the formation of surface wetness. Methanol may adsorb to or dissolve in this surface water and eventually be chemically or biologically removed from it. Management activities in agriculture and forestry are shown to increase local methanol emission by orders of magnitude; they are however neglected at present in global budgets. While contemporary net land methanol budgets are overall consistent with the grand mean of the micrometeorological methanol flux measurements, we caution that the present approach of simulating methanol emission and deposition separately is prone to opposing systematic errors and does not allow taking full

  6. Direction Dependent Effects In Wide-Field Wideband Full Stokes Radio Imaging

    CERN Document Server

    Jagannathan, Preshanth; Rau, Urvashi; Taylor, Russ

    2014-01-01

    Synthesis imaging in radio astronomy is affected by instrumental and atmospheric effects which introduce direction-dependent (DD) gains.The antenna power pattern varies both as a function of time and frequency. The broad band time varying nature of the antenna power pattern when not corrected leads to gross errors in full Stokes imaging and flux estimation. In this poster we explore the errors that arise in image deconvolution while not accounting for the time and frequency dependence of the antenna power pattern. Simulations were conducted with the wide-band full Stokes power pattern of the Karl G. Jansky Very Large Array (VLA) antennas to demonstrate the level of errors arising from direction-dependent gains and their non-neglegible impact on upcoming sky surveys such as the VLASS. DD corrections through hybrid projection algorithms are computationally expensive to perform. A highly parallel implementation through high performance computing architectures is the only feasible way of applying these correction...

  7. Full-parallax three-dimensional display using new directional diffuser

    Institute of Scientific and Technical Information of China (English)

    Shuai Li; Haifeng Li; Zhenrong Zheng; Yifan Peng; Shicong Wang; Xu Liu

    2011-01-01

    @@ A full-parallax three-dimensional(3D) display using a new directional diffuser is demonstrated.The display could present 3D images with 45 views comprising 9 horizontal views by 5 vertical views.The resolution and size of the 3D images displayed are 226×226 pixels and 300×300(mm).The new directional diffuser consisting of two perpendicular lenticular sheets can be widely used in the display domain owing to its low cost and simple process.%A full-parallax three-dimensional (3D) display using a new directional diffuser is demonstrated. The display could present 3D images with 45 views comprising 9 horizontal views by 5 vertical views. The resolution and size of the 3D images displayed are 226×226 pixels and 300×300 (mm). The new directional diffuser consisting of two perpendicular lenticular sheets can be widely used in the display domain owing to its low cost and simple process.

  8. Visualizing ignition and combustion of methanol mixtures in a diesel engine; Methanol funmu no glow chakka to nensho no kashika

    Energy Technology Data Exchange (ETDEWEB)

    Inomoto, Y.; Harada, T.; Kusaka, J.; Daisho, Y.; Kihara, R.; Saito, T. [Waseda University, Tokyo (Japan)

    1997-10-01

    A glow-assisted ignition system tends to suffer from poor ignitability and slow flame propagation at low load in a direct-injection diesel engine fueled with methanol. To investigate the ignition process and improve such disadvantages, methanol sprays, their ignition and flames were visualized at high pressures and temperatures using a modified two-stroke engine. The results show that parameters influencing ignition, the location of a glow-plug, swirl level, pressure and temperature are important. In addition, a full kinetics calculation was conducted to predict the delay of methanol mixture ignition by taking into account 39 chemical species and 157 elementary reactions. 3 refs., 9 figs.

  9. Performance analysis and fuzzy neural networks modeling of direct methanol fuel cell%基于参数自调整模糊神经网络的直接甲醇燃料电池电特性分析

    Institute of Scientific and Technical Information of China (English)

    苗青; 曹广益; 朱新坚

    2007-01-01

    This paper introduces the effects of cell operating temperature, methanol concentration and airflow rate, respectively, on the performance of direct methanol fuel cell (DMFC). A novel method based on fuzzy neural networks identification technique is proposed to establish the performance model of DMFC. Three dynamic performance models of DMFC under the influences of cell operating temperature, methanol concentration, and airflow rate are identified and established separately.Simulation results show that modeling using fuzzy neural networks identification is satisfactory with high accuracy. It is applicable to DMFC control systems.

  10. Direct synthesis of dimethyl carbonate from methanol and carbon dioxide over CeO2(X)-ZnO(1-X) nano-catalysts.

    Science.gov (United States)

    Kang, Ki Hyuk; Joe, Wangrae; Lee, Chang Hoon; Kim, Mieock; Kim, Dong Baek; Jang, Boknam; Song, In Kyu

    2013-12-01

    CeO2(X)-ZnO(1-X) (X = 0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1.0) nano-catalysts were prepared by a co-precipitation method with a variation of CeO2 content (X, mol%), and they were applied to the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. Successful formation of CeO2(X)-ZnO(1-X) nano-catalysts was well confirmed by XRD analysis. The amount of DMC produced over CeO2(X)-ZnO(1-X) catalysts exhibited a volcano-shaped curve with respect to CeO2 content. Acidity and basicity of CeO2(X)-ZnO(1-X) nano-catalysts were measured by NH3-TPD and CO2-TPD experiments, respectively, to elucidate the effect of acidity and basicity on the catalytic performance in the reaction. It was revealed that the catalytic performance of CeO2(X)-ZnO(1-X) nano-catalysts was closely related to the acidity and basicity of the catalysts. Amount of dimethyl carbonate increased with increasing both acidity and basicity of the catalysts. Among the catalysts tested, CeO2(0.7)-ZnO(0.3) with the largest acidity and basicity showed the best catalytic performance in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide.

  11. Fabrication of Highly Stable and Efficient PtCu Alloy Nanoparticles on Highly Porous Carbon for Direct Methanol Fuel Cells.

    Science.gov (United States)

    Khan, Inayat Ali; Qian, Yuhong; Badshah, Amin; Zhao, Dan; Nadeem, Muhammad Arif

    2016-08-17

    Boosting the durability of Pt nanoparticles by controlling the composition and morphology is extremely important for fuel cells commercialization. We deposit the Pt-Cu alloy nanoparticles over high surface area carbon in different metallic molar ratios and optimize the conditions to achieve desired material. The novel bimetallic electro-catalyst {Pt-Cu/PC-950 (15:15%)} offers exceptional electrocatalytic activity when tested for both oxygen reduction reaction and methanol oxidation reactions. A high mass activity of 0.043 mA/μgPt (based on Pt mass) is recorded for ORR. An outstanding longevity of this electro-catalyst is noticed when compared to 20 wt % Pt loaded either on PC-950 or commercial carbon. The high surface area carbon support offers enhanced activity and prevents the nanoparticles from agglomeration, migration, and dissolution as evident by TEM analysis.

  12. Studies on the direct methanol fuel cell: Characterization of proton conducting polymer membranes and investigations of current distribution at the cathode

    Energy Technology Data Exchange (ETDEWEB)

    Saarinen, V.

    2007-07-01

    Novel proton conducting membranes for the direct methanol fuel cell (DMFC) are characterized widely by combining methods of physical chemistry, electrochemistry and material science. This work mainly concentrates on the sulphonated poly(ethylene-alt-tetrafluoroethylene) (ETFE-SA) membrane. Other investigated membranes are poly(vinylidene fluoride)-graft-poly(styrene sulphonic acid) (PVDF-g-PSSA), sulphonated poly(phenylene sulphone) (sPSO{sub 2}) and the commercial Nafion membrane as a reference material. The swelling properties of the membranes are investigated in different alcohol - water and H2SO{sub 4} - water mixtures. Clear trends are observed for the water / alcohol selectivity: preferential water uptake (alcohol rejection) correlates with high ion exchange capacity (IEC) and low solvent uptake (swelling). The total swelling significantly decreases in the presence of H2SO{sub 4} indicating that osmosis is a major driving force in the swelling process. The membrane properties are characterized with sophisticated microscopic techniques (AFM, SEM and EDX, SECM) and many benefits of the extensive characterization are demonstrated. The surface hydrophobicity is investigated by water contact angle (CA) measurement. During the measurements, the surface properties of the different membranes are found to differ significantly from each other and the properties of the ETFE-SA membrane to vary also as a function of the manufacturing parameters. Also, the ETFE-SA membrane has exceptionally low water uptake, high water selectivity against methanol and good chemical and mechanical stability. Methanol permeability through the membranes is investigated both with a diffusion cell and under actual DMFC conditions. The membranes are investigated in a laboratory-scale DMFC system and the connections between different operation parameters are clarified in detail. The main observation is that durability of ETFE-SA is sufficient for DMFC applications at low temperatures (T < 80 +-C

  13. Exploring Direct 3D Interaction for Full Horizontal Parallax Light Field Displays Using Leap Motion Controller

    Directory of Open Access Journals (Sweden)

    Vamsi Kiran Adhikarla

    2015-04-01

    Full Text Available This paper reports on the design and evaluation of direct 3D gesture interaction with a full horizontal parallax light field display. A light field display defines a visual scene using directional light beams emitted from multiple light sources as if they are emitted from scene points. Each scene point is rendered individually resulting in more realistic and accurate 3D visualization compared to other 3D displaying technologies. We propose an interaction setup combining the visualization of objects within the Field Of View (FOV of a light field display and their selection through freehand gesture tracked by the Leap Motion Controller. The accuracy and usefulness of the proposed interaction setup was also evaluated in a user study with test subjects. The results of the study revealed high user preference for free hand interaction with light field display as well as relatively low cognitive demand of this technique. Further, our results also revealed some limitations and adjustments of the proposed setup to be addressed in future work.

  14. Development of direct methanol fuel cells for the applications in mining and tunnelling. Automation and power conditioning of a fuel cell-battery hybrid system

    Energy Technology Data Exchange (ETDEWEB)

    Kulakarni, Sreekantha Rao

    2012-07-01

    In mining and tunneling, there are many decentralized types of power-consuming equipment for which the issue of power supply has not yet been resolved satisfactorily. This equipment includes electro-hydraulic control of shield-type supports, gas detection systems, seismic measuring devices, radio relay stations, access points for wireless networks, water level monitoring stations and the power supply for repair stations as well as special alarm signals in combination with gas detectors. The decentralized power consumers in mining and tunneling cannot be supplied by cable, because of their remote location and the fact that the installation of cables is extremely costly. The other alternative, the power supply by means of rechargeable batteries, requires regular charging and transportation between charging and workstations. Due to the large distances that may be necessary, this task can stress several workers and vehicles around the clock. Pit lamps carried by the miners are quite heavy due to rechargeable batteries. The weight of these pit lamps must be reduced. Fuel cells will provide the solution to the problems mentioned above. They are lighter in weight, since they have a higher energy density than can be reached by commercially-available batteries, and they provide electrical power as long as the fuel is delivered. The most widely used fuel in the fuel cell is hydrogen, but hydrogen is not readily available in nature. Therefore, it must be reformed from other fuels such as natural gas and there are still some barriers in the production, transportation and storage of hydrogen. Due to lower density, hydrogen must be stored in compressed cylinders. Normally hydrogen is stored in cylinders at a pressure of 700 bar (i.e. highly compressed gas cylinders). Since, hydrogen is an explosive gas; usage of such highly compressed gas cylinders is prohibited in underground mining for security reasons. Under this aspect, direct methanol fuel cells (DMFCs) are the most

  15. Atmospheric methanol measurement using selective catalytic methanol to formaldehyde conversion

    Directory of Open Access Journals (Sweden)

    S. J. Solomon

    2005-01-01

    Full Text Available A novel atmospheric methanol measurement technique, employing selective gas-phase catalytic conversion of methanol to formaldehyde followed by detection of the formaldehyde product, has been developed and tested. The effects of temperature, gas flow rate, gas composition, reactor-bed length, and reactor-bed composition on the methanol conversion efficiency of a molybdenum-rich, iron-molybdate catalyst [Mo-Fe-O] were studied. Best results were achieved using a 1:4 mixture (w/w of the catalyst in quartz sand. Optimal methanol to formaldehyde conversion (>95% efficiency occurred at a catalyst housing temperature of 345°C and an estimated sample-air/catalyst contact time of <0.2 seconds. Potential interferences arising from conversion of methane and a number of common volatile organic compounds (VOC to formaldehyde were found to be negligible under most atmospheric conditions and catalyst housing temperatures. Using the new technique, atmospheric measurements of methanol were made at the University of Bremen campus from 1 to 15 July 2004. Methanol mixing ratios ranged from 1 to 5 ppb with distinct maxima at night. Formaldehyde mixing ratios, obtained in conjunction with methanol by periodically bypassing the catalytic converter, ranged from 0.2 to 1.6 ppb with maxima during midday. These results suggest that selective, catalytic methanol to formaldehyde conversion, coupled with existing formaldehyde measurement instrumentation, is an inexpensive and effective means for monitoring atmospheric methanol.

  16. Atmospheric methanol measurement using selective catalytic methanol to formaldehyde conversion

    Directory of Open Access Journals (Sweden)

    S. J. Solomon

    2005-05-01

    Full Text Available A novel atmospheric methanol measurement technique, employing selective gas-phase catalytic conversion of methanol to formaldehyde followed by detection of the formaldehyde product, has been developed and tested. The effects of temperature, gas flow rate, gas composition, reactor-bed length, and reactor-bed composition on the methanol conversion efficiency of a molybdenum-rich, iron-molybdate catalyst [Mo-Fe-O] were studied. Best results were achieved using a 1:4 mixture (w/w of the catalyst in quartz sand. Optimal methanol to formaldehyde conversion (>95% efficiency occurred at a catalyst housing temperature of 345°C and an estimated sample-air/catalyst contact time of <0.2 s. Potential interferences arising from conversion of methane and a number of common volatile organic compounds (VOC to formaldehyde were found to be negligible under most atmospheric conditions and catalyst housing temperatures. Using the new technique, atmospheric measurements of methanol were made at the University of Bremen campus from 1 to 15 July 2004. Methanol mixing ratios ranged from 1 to 5 ppb with distinct maxima at night. Formaldehyde mixing ratios, obtained in conjunction with methanol by periodically bypassing the catalytic converter, ranged from 0.2 to 1.6 ppb with maxima during midday. These results suggest that selective, catalytic methanol to formaldehyde conversion, coupled with existing formaldehyde measurement instrumentation, is an inexpensive and effective means for monitoring atmospheric methanol.

  17. Considerations of the Effects of Naphthalene Moieties on the Design of Proton-Conductive Poly(arylene ether ketone) Membranes for Direct Methanol Fuel Cells.

    Science.gov (United States)

    Wang, Baolong; Hong, Lihua; Li, Yunfeng; Zhao, Liang; Wei, Yuxue; Zhao, Chengji; Na, Hui

    2016-09-14

    Novel sulfonated poly(arylene ether ketones) (SDN-PAEK-x), consisting of dual naphthalene and flexible sulfoalkyl groups, were prepared via polycondensation, demethylation, and sulfobutylation grafting reaction. Among them, SDN-PAEK-1.94 membrane with the highest ion exchange capacity (IEC = 2.46 mequiv·g(-1)) exhibited the highest proton conductivity, which was 0.147 S· cm(-1) at 25 °C and 0.271 S·cm(-1) at 80 °C, respectively. The introduction of dual naphthalene moieties is expected to achieve much enhanced properties compared to those of sulfonated poly(arylene ether ketones) (SNPAEK-x), consisting of single naphthalene and flexible sulfoalkyl groups. Compared with SNPAEK-1.60 with a similar IEC, SDN-PAEK-1.74 membrane showed higher proton conductivity, higher IEC normalized conductivity, and higher effective proton mobility, although it had lower analytical acid concentration. The SDN-PAEK-x membranes with IECs higher than 1.96 mequiv·g(-1) also exhibited higher proton conductivity than that of recast Nafion membrane. Furthermore, SDN-PAEK-1.94 displayed a better single cell performance with a maximum power density of 60 mW·cm(-2) at 80 °C. Considering its high proton conductivity, excellent single cell performance, good mechanical stabilities, low membrane swelling, and methanol permeability, SDN-PAEK-x membranes are promising candidates as alternative polymer electrolyte membranes to Nafion for direct methanol fuel cell applications.

  18. A feasibility study on direct methanol fuel cells for laptop computers based on a cost comparison with lithium-ion batteries

    Science.gov (United States)

    Wee, Jung-Ho

    This paper compares the total cost of direct methanol fuel cell (DMFC) and lithium (Li)-ion battery systems when applied as the power supply for laptop computers in the Korean environment. The average power output and operational time of the laptop computers were assumed to be 20 W and 3000 h, respectively. Considering the status of their technologies and with certain conditions assumed, the total costs were calculated to be US140 for the Li-ion battery and US362 for DMFC. The manufacturing costs of the DMFC and Li-ion battery systems were calculated to be 16.65 W -1 and 0.77 W h -1, and the energy consumption costs to be 0.00051 W h -1 and 0.00032 W h -1, respectively. The higher fuel consumption cost of the DMFC system was due to the methanol (MeOH) crossover loss. Therefore, the requirements for DMFCs to be able to compete with Li-ion batteries in terms of energy cost include reducing the crossover level to at an order magnitude of -9 and the MeOH price to under 0.5 kg -1. Under these conditions, if the DMFC manufacturing cost could be reduced to 6.30 W -1, then the DMFC system would become at least as competitive as the Li-ion battery system for powering laptop computers in Korea.

  19. Performance comparison of portable direct methanol fuel cell mini-stacks based on a low-cost fluorine-free polymer electrolyte and Nafion membrane

    Energy Technology Data Exchange (ETDEWEB)

    Baglio, V., E-mail: baglio@itae.cnr.i [CNR-ITAE, Via Salita S. Lucia sopra Contesse 5, 98126 Messina (Italy); Stassi, A.; Modica, E.; Antonucci, V.; Arico, A.S. [CNR-ITAE, Via Salita S. Lucia sopra Contesse 5, 98126 Messina (Italy); Caracino, P.; Ballabio, O.; Colombo, M.; Kopnin, E. [Pirelli Labs, Viale Sarca, 222, 20126 Milano (Italy)

    2010-08-01

    A low-cost fluorine-free proton conducting polymer electrolyte was investigated for application in direct methanol fuel cell (DMFC) mini-stacks. The membrane consisted of a sulfonated polystyrene grafted onto a polyethylene backbone. DMFC operating conditions specifically addressing portable applications, i.e. passive mode, air breathing, high methanol concentration, room temperature, were selected. The device consisted of a passive DMFC monopolar three-cell stack. Two designs for flow-fields/current collectors based on open-flow or grid-like geometry were investigated. An optimization of the mini-stack structure was necessary to improve utilization of the fluorine-free membrane. Titanium-grid current collectors with proper mechanical stiffness allowed a significant increase of the performance by reducing contact resistance even in the case of significant swelling. A single cell maximum power density of about 18 mW cm{sup -2} was achieved with the fluorine-free membrane at room temperature under passive mode. As a comparison, the performance obtained with Nafion 117 membrane and Ti grids was 31 mW cm{sup -2}. Despite the lower performance, the fluorine-free membrane showed good characteristics for application in portable DMFCs especially with regard to the perspectives of significant cost reduction.

  20. Effect of current collector corrosion made from printed circuit board (PCB) on the degradation of self-breathing direct methanol fuel cell stack

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jian-Wei; Xie, Xiao-Feng; Wang, Jin-Hai; Shang, Yu-Ming [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China)

    2008-02-25

    Adopting printed circuit board (PCB) as the current collector for direct methanol fuel cell (DMFC) is a promising task. This paper found that the combinational 10 {mu}m Ni/2 {mu}m Au coatings on PCB could not endure halide attacking in its anodic polarization. With this coated PCB, the self-breathing DMFC stack with passive methanol supply exhibited progressively degradation in its lifetime test. By using a series of measurements, it is shown that initial corrosion would not obviously influence stack degradation, but the subsequently inter-facilitation, between F{sup -} originating from Nafion membrane and corrosion products of Ni{sup 2+} and Cu{sup 2+} from PCB, would result in serious degradation, the final stack invalidation would present accompanied with the loss of membrane conductivity. The defects on coated PCB are crucial to initiate localized corrosion and stack degradation. Although cyclic voltammetry (CV) technology is effective to recover cell temporarily, its damage by releasing F{sup -} should be further evaluated. (author)

  1. Synthesis of PtRu nanoparticles from the hydrosilylation reaction and application as catalyst for direct methanol fuel cell.

    Science.gov (United States)

    Huang, Junchao; Liu, Zhaolin; He, Chaobin; Gan, Leong Ming

    2005-09-08

    Nanosized Pt, PtRu, and Ru particles were prepared by a novel process, the hydrosilylation reaction. The hydrosilylation reaction is an effective method of preparation not only for Pt particles but also for other metal colloids, such as Ru. Vulcan XC-72 was selected as catalyst support for Pt, PtRu, and Ru colloids, and TEM investigations showed nanoscale particles and narrow size distribution for both supported and unsupported metals. All Pt and Pt-rich catalysts showed the X-ray diffraction pattern of a face-centered cubic (fcc) crystal structure, whereas the Ru and Ru-rich alloys were more typical of a hexagonal close-packed (hcp) structure. As evidenced by XPS, most Pt and Ru atoms in the nanoparticles were zerovalent, except a trace of oxidation-state metals. The electrooxidation of liquid methanol on these catalysts was investigated at room temperature by cyclic voltammetry and chronoamperometry. The results concluded that some alloy catalysts showed higher catalytic activities and better CO tolerance than the Pt-only catalyst; Pt56Ru44/C have displayed the best electrocatalytic performance among all carbon-supported catalysts.

  2. Does direction of results of abstracts submitted to scientific conferences on drug addiction predict full publication?

    Directory of Open Access Journals (Sweden)

    Davoli Marina

    2009-04-01

    Full Text Available Abstract Background Data from scientific literature show that about 63% of abstracts presented at biomedical conferences will be published in full. Some studies have indicated that full publication is associated with the direction of results (publication bias. No study has looked into the occurrence of publication bias in the field of addiction. Objectives To investigate whether the significance or direction of results of abstracts presented at the major international scientific conference on addiction is associated with full publication Methods The conference proceedings of the US Annual Meeting of the College on Problems of Drug Dependence (CPDD, were handsearched for abstracts of randomized controlled trials and controlled clinical trials that evaluated interventions for prevention, rehabilitation and treatment of drug addiction in humans (years searched 1993–2002. Data regarding the study designs and outcomes reported were extracted. Subsequent publication in peer reviewed journals was searched in MEDLINE and EMBASE databases, as of March 2006. Results Out of 5919 abstracts presented, 581 met the inclusion criteria; 359 (62% conference abstracts had been published in a broad variety of peer reviewed journals (average time of publication 2.6 years, SD +/- 1.78. The proportion of published studies was almost the same for randomized controlled trials (62.4% and controlled clinical trials (59.5% while studies that reported positive results were significantly more likely to be published (74.5% than those that did not report statistical results (60.9%., negative or null results (47.1% and no results (38.6%, Abstracts reporting positive results had a significantly higher probability of being published in full, while abstracts reporting null or negative results were half as likely to be published compared with positive ones (HR = 0.48; 95%CI 0.30–0.74 Conclusion Clinical trials were the minority of abstracts presented at the CPDD; we found

  3. Influence of Synthesis pH on Textural Properties of Carbon Xerogels as Supports for Pt/CXs Catalysts for Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    C. Alegre

    2012-01-01

    Full Text Available Carbon xerogels (CXs have been prepared by polycondensation of resorcinol and formaldehyde. Two synthesis pHs were studied in order to evaluate its influence on the electrochemical behaviour of Pt catalysts supported on previous carbon xerogels, synthesized by conventional impregnation method. Catalysts were also synthesized over a commercial carbon black (Vulcan-XC-72R for comparison purposes. Characterization techniques included nitrogen physisorption, scanning electron microscopy, and X-ray diffraction. Catalysts electrochemical activity towards the oxidation of carbon monoxide and methanol was studied by cyclic voltammetry and chronoamperometry to establish the effect of the carbon support on the catalysts performance. Commercial Pt/C catalyst (E-TEK was analyzed for comparison purposes. It was observed that the more developed and mesopore-enriched porous structure of the carbon xerogel synthesized at a higher initial pH resulted in an optimal utilization of the active phase and in an enhanced and promising catalytic activity in the electrooxidation of methanol, in comparison with commercial catalysts.

  4. Full-direct method for imaging pharmacokinetic parameters in dynamic fluorescence molecular tomography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guanglei, E-mail: guangleizhang@bjtu.edu.cn [Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084 (China); Department of Biomedical Engineering, School of Computer and Information Technology, Beijing Jiaotong University, Beijing 100044 (China); Pu, Huangsheng; Liu, Fei; Bai, Jing [Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084 (China); He, Wei [China Institute of Sport Science, Beijing 100061 (China); Luo, Jianwen, E-mail: luo-jianwen@tsinghua.edu.cn [Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084 (China); Center for Biomedical Imaging Research, School of Medicine, Tsinghua University, Beijing 100084 (China)

    2015-02-23

    Images of pharmacokinetic parameters (also known as parametric images) in dynamic fluorescence molecular tomography (FMT) can provide three-dimensional metabolic information for biological studies and drug development. However, the ill-posed nature of FMT and the high temporal variation of fluorophore concentration together make it difficult to obtain accurate parametric images in small animals in vivo. In this letter, we present a method to directly reconstruct the parametric images from the boundary measurements based on hybrid FMT/X-ray computed tomography (XCT) system. This method can not only utilize structural priors obtained from the XCT system to mitigate the ill-posedness of FMT but also make full use of the temporal correlations of boundary measurements to model the high temporal variation of fluorophore concentration. The results of numerical simulation and mouse experiment demonstrate that the proposed method leads to significant improvements in the reconstruction quality of parametric images.

  5. Full-direct method for imaging pharmacokinetic parameters in dynamic fluorescence molecular tomography

    Science.gov (United States)

    Zhang, Guanglei; Pu, Huangsheng; He, Wei; Liu, Fei; Luo, Jianwen; Bai, Jing

    2015-02-01

    Images of pharmacokinetic parameters (also known as parametric images) in dynamic fluorescence molecular tomography (FMT) can provide three-dimensional metabolic information for biological studies and drug development. However, the ill-posed nature of FMT and the high temporal variation of fluorophore concentration together make it difficult to obtain accurate parametric images in small animals in vivo. In this letter, we present a method to directly reconstruct the parametric images from the boundary measurements based on hybrid FMT/X-ray computed tomography (XCT) system. This method can not only utilize structural priors obtained from the XCT system to mitigate the ill-posedness of FMT but also make full use of the temporal correlations of boundary measurements to model the high temporal variation of fluorophore concentration. The results of numerical simulation and mouse experiment demonstrate that the proposed method leads to significant improvements in the reconstruction quality of parametric images.

  6. Enhanced oxygen reduction reaction activity of iron-containing nitrogen-doped carbon nanotubes for alkaline direct methanol fuel cell application

    Science.gov (United States)

    Ratso, Sander; Kruusenberg, Ivar; Sarapuu, Ave; Rauwel, Protima; Saar, Rando; Joost, Urmas; Aruväli, Jaan; Kanninen, Petri; Kallio, Tanja; Tammeveski, Kaido

    2016-11-01

    Non-precious metal catalysts for electrochemical oxygen reduction reaction are synthesised by pyrolysis of multi-walled carbon nanotubes in the presence of nitrogen and iron precursors. For the physico-chemical characterisation of the catalysts transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction are used. The electrocatalytic activity of the catalysts for oxygen reduction is studied in 0.1 M KOH solution using the rotating disk electrode method. The Fe-containing nitrogen-doped carbon nanotubes exhibit an enhanced electrocatalytic performance as compared to metal-free counterparts and their electrocatalytic activity is comparable to that of commercial Pt/C catalyst. Alkaline direct methanol fuel cell tests also show performance close to Pt/C. Thus, these materials can be considered as promising cathode catalysts for application in alkaline fuel cells.

  7. 微型直接甲醇燃料电池的研究进展%Research progress in micro direct methanol fuel cell

    Institute of Scientific and Technical Information of China (English)

    王一拓; 刘桂成; 王萌; 王新东

    2012-01-01

    The special modification for micro direct methanol fuel cell (μDMFC) used membrane electrode assembly (MEA) was introduced to overcome the unique problem as the low liquidity of fuel and oxide, as well as the cathode structural flooding. The progress in fuel storage and supply, collector progressing along with stack design was introduced. The development and improvement of μDMFC were prospected.%介绍了微型直接甲醇燃料电池(μDMFC)用膜电极组件(MEA)的特殊改性,以克服燃料和氧化物低流通性及阴极结构性水淹的问题;介绍了μDMFC的原料储存供应、集电板加工和堆体设计的进展;对μDMFC的发展和改进进行了展望.

  8. 直接甲醇燃料电池的模糊PID控制研究%Fuzzy PID control of the direct methanol fuel cell

    Institute of Scientific and Technical Information of China (English)

    廉洁; 陈雨

    2012-01-01

    The direct methanol fuel cell(DMFC) is regarded as a complex nonlinear systems.With the help of modern control theory and fuzzy control technology,the state space model is established,the adaptive parameters fuzzy PID controller is designed,fuzzy control rules are provided,and a multi input-output system is converted to a single input-output system.Using Matlab simulation software simulation of the system is made in which the cathode air feed speed is the input quantities and the output power is output quantity.The results show that designed control program can effectively improve the performance of the DMFC system.%视直接甲醇燃料电池DMFC(Direct Methanol Fuel Cell)为复杂的非线性系统,综合应用现代控制理论和模糊控制技术,建立状态空间模型,设计参数自适应模糊PID控制器,规定模糊控制规则,把多输入多输出系统转换为单输入单输出系统.采用Matlab软件,对以阴极空气进料速度为输入量,以电堆的输出功率为输出量的系统进行仿真.结果表明,所设计的控制方案能够有效提高DMFC系统的工作性能.

  9. An Integrated Microfluidic Chip for Rapid Methanol Detection

    Directory of Open Access Journals (Sweden)

    Ting-Fu Hong

    2012-03-01

    Full Text Available A widely-available CO2 laser scriber is used to perform direct-writing ablation on a poly(methyl methacrylate (PMMA substrate to create a microfluidic chip for the rapid detection of methanol. The microfluidic designs are created using commercial layout software and are converted into the command signals required to drive the laser scriber in such a way as to reproduce the desired microchannel configuration on the surface of a PMMA substrate. Experimental results indicate that, using the proposed integrated microfluidic chip, linearity expression R2 can reach 0.9972 when using 2 unit methanol oxidase (MOX and basic fuchsin to detect methanol. The proposed device is thus a valuable tool for rapid methanol detection, with its micro mixer system providing a simple yet effective solution for mixing problems in the field of micro-total-analysis-systems.

  10. Methanol as an energy carrier

    Energy Technology Data Exchange (ETDEWEB)

    Biedermann, P.; Grube, T.; Hoehlein, B. (eds.)

    2006-07-01

    For the future, a strongly growing energy demand is expected in the transport sector worldwide. Economically efficient oil production will run through a maximum in the next decade. Higher fuel prices and an environmentally desirable reduction of emissions will increase the pressure for reducing fuel consumption and emissions in road traffic. These criteria show the urgent necessity of structural changes in the fuel market. Due to its advantages concerning industrial-scale production, storage and global availability, methanol has the short- to medium-term potential for gaining increased significance as a substitution product in the energy market. Methanol can be produced both from fossil energy sources and from biomass or waste materials through the process steps of synthesis gas generation with subsequent methanol synthesis. Methanol has the potential to be used in an environmentally friendly manner in gasoline/methanol mixtures for flexible fuel vehicles with internal combustion engines and in diesel engines with pure methanol. Furthermore, it can be used in fuel cell vehicles with on-board hydrogen production in direct methanol fuel cell drives, and in stationary systems for electricity and heat generation as well as for hydrogen production. Finally, in portable applications it serves as an energy carrier for electric power generation. In this book, the processes for the production and use of methanol are presented and evaluated, markets and future options are discussed and issues of safety and environmental impacts are addressed by a team of well-known authors. (orig.)

  11. Full three-dimensional direction-dependent x-ray scattering tomography

    Science.gov (United States)

    Zhu, Zheyuan; Pang, Shuo

    2017-03-01

    Small-angle X-ray scattering (SAXS) detects the angular-dependent, coherently scattered X-ray photons, which provide improved contrast among different types of tissues or materials in medical diagnosis and material characterizations. By combining SAXS with computed tomography (CT), coherent scattering computed tomography (CSCT) enables the detection of spatially-resolved, material-specific scattering profile inside an extended object. However, conventional CSCT lacks the ability to distinguish direction-dependent coherent scattering signal, because of its assumptions that the materials are amorphous with isotropic scattering profiles. To overcome this issue, we propose a new CSCT imaging strategy, which can resolve the three-dimensional scattering profile for each object pixel, by incorporating detector movement into each CSCT projection measurement. The full reconstruction of the three-dimensional momentum transfer profile of a two-dimensional object has been successfully demonstrated. Our setup only requires a table-top Xray source and a panel detector. The presented method demonstrates the potential to achieve low-cost, high-specificity X-ray tissue imaging and material characterization.

  12. Methodology for full comparative assessment of direct gross glycerin combustion in a flame tube furnace

    Energy Technology Data Exchange (ETDEWEB)

    Maturana, Aymer Yeferson; Pagliuso, Josmar D. [Dept. of Mechanical Engineering. Sao Carlos School of Engineering. University of Sao Paulo, Sao Carlos, SP (Brazil)], e-mails: aymermat@sc.usp.br, josmar@sc.usp.br

    2010-07-01

    This study is to develop a methodology to identify and evaluate the emissions and heat transfer associated to combustion of gross glycerin a by-product of the Brazilian biodiesel manufacture process as alternative energy source. It aims to increase the present knowledge on the matter and to contribute to the improvement of the economic and environmental perspective of biodiesel industry. This methodology was considered to be used for assessment of gross glycerin combustion from three different types of biodiesel (bovine tallow, palm and soy). The procedures for evaluation and quantification of emissions of sulphur and nitrogen oxides, total hydrocarbons, carbon monoxide, carbon dioxide, and acrolein were analyzed, described and standardized. Experimental techniques for mutagenic and toxic effects assessment of gases similarly were analyzed and standardized, as well as the calorific power, the associate heat transfer and fundamentals operational parameters. The methodology was developed, using a full-instrumented flame tube furnace, continuous gas analyzers, a chromatograph, automatic data acquisition systems and other auxiliary equipment. The mutagenic and toxic effects of the study was based on Tradescantia clone KU-20, using chambers of intoxication and biological analytical techniques previously developed and others were specially adapted. The benchmark for the initial set up was based on the performance evaluation of the previous equipment tested with diesel considering its behavior during direct combustion. Finally, the following factors were defined for the combustion of crude glycerin, configurations of equipment types, operational parameters such as air fuel ratio adiabatic temperature and other necessary aspect for successful application of the methodology. The developed and integrated methodology was made available to the concern industry, environmental authorities and researchers as procedures to access the viability of gross glycerin or similar fuels as

  13. Electrochemical evaluation of Pt-Based binary catalysts on various supports for the direct methanol fuel cell

    CSIR Research Space (South Africa)

    Khotseng, L

    2016-01-01

    Full Text Available patterns similar to that of the Pt/C electrocatalyst, an indication that the catalysts have predominantly the Pt face-centered cubic (fcc) crystal structure. High-resolution transmission electron microscopy (HRTEM) images showed spherical PtRu and Pt...

  14. Sample introduction systems for reversed phase LC-ICP-MS of selenium using large amounts of methanol - comparison of systems based on membrane desolvation, a spray chamber and direct injection

    DEFF Research Database (Denmark)

    Bendahl, L.; Gammelgaard, Bente

    2005-01-01

    nebuliser (MCN) in combination with a membrane desolvator ( MD), a MCN in combination with a cyclonic spray chamber ( CS) and a direct injection nebuliser ( DIN), respectively. Thirteen selenium standards diluted in 50% methanol were introduced in each system at a flow rate of 50 mu l min(-1). Except...

  15. Method for making methanol

    Science.gov (United States)

    Mednick, R. Lawrence; Blum, David B.

    1986-01-01

    Methanol is made in a liquid-phase methanol reactor by entraining a methanol-forming catalyst in an inert liquid and contacting said entrained catalyst with a synthesis gas comprising hydrogen and carbon monoxide.

  16. Critical Materials and Technology in Direct Methanol Fuel Cells%直接甲醇燃料电池关键材料与技术

    Institute of Scientific and Technical Information of China (English)

    王新东; 谢晓峰; 王萌; 刘桂成; 苗睿瑛; 王一拓; 阎群

    2011-01-01

    Direct methanol fuel cells (DMFCs) are known as the most promising green power source, have acknowledged special superiorities and already obtained primary effects on commercialization. In this article, based on membrane electrode assembly (MEA), which is the key component of a DMFC, the preparation and optimization progress of catalyst, proton exchange membrane (PEM) , the preparation of MEA, as well as the current reseach situation of activation technology for MEA are detailed combined with our experimental work. The process of multi-step activation, the method of MEA regeneration and the test technology of the current fraction of CO2 are presented and the catalyst nucleation mechanism, PEM mass transfer mechanism and the benefit of methanol penetrating are discussed, as well. Moreover, future work is forecasted. Based on the macromolecule polymer molding theory, a new thought is proposed in this paper that the catalyst slurry is directly sprayed on PEM to form the three-dimensional network structure, which will realize the gradient catalysis functionality and improve the preparation of catalyst layer of MEA. Finally, this article also describes the flow field design, performance testing and system control and other aspects of research status.%作为绿色能源,直接甲醇燃料电池(DMFC)发展潜力无限,有着独特优势,且已有商业化萌芽.本文以DMFC中关键组件膜电极(MEA)为基础,主要介绍了制备高催化性能的电催化剂、高阻醇性能的质子交换膜(PEM)和高性能的MEA工艺,阐述了高效多层次活化、MEA性能再生等研究概念以及CO2分电流的测试技术,还对催化剂成核机理、PEM传质机理、甲醇的有益渗透理论和北京科技大学关于利用高分子成型理论将催化剂浆料直接喷涂在PEM上形成立体三维网格结构实现梯度催化的催化层制备思路进行了探讨.最后,本文还介绍了流场设计,性能测试和系统控制等方面的研究现状.

  17. Full-chip characterization of compression algorithms for direct-write maskless lithography systems

    Science.gov (United States)

    Zakhor, Avideh; Dai, Vito; Cramer, George

    2009-03-01

    Future lithography systems must produce more dense microchips with smaller feature sizes, while maintaining throughput comparable to today's optical lithography systems. This places stringent data-handling requirements on the design of any maskless lithography system. Today's optical lithography systems transfer one layer of data from the mask to the entire wafer in about sixty seconds. To achieve a similar throughput for a direct-write maskless lithography system with a pixel size of 22 nm, data rates of about 12 Tb/s are required. Over the past 8 years, we have proposed a datapath architecture for delivering such a data rate to a parallel array of writers. Our proposed system achieves this data rate contingent on two assumptions: consistent 10 to 1 compression of lithography data, and implementation of real-time hardware decoder, fabricated on a microchip together with a massively parallel array of lithography writers, capable of decoding 12 Tb/s of data. To address the compression efficiency problem, in the past few years, we have developed a new technique, Context Copy Combinatorial Coding (C4), designed specifically for microchip layer images, with a low-complexity decoder for application to the datapath architecture. C4 combines the advantages of JBIG and ZIP, to achieve compression ratios higher than existing techniques. We have also devised Block C4, a variation of C4 with up to hundred times faster encoding times, with little or no loss in compression efficiency. While our past work has focused on characterizing the compression efficiency of C4 and Block C4 on samples of a variety of industrial layouts, there has been no full chip performance characterization of these algorithms. In this paper, we show compression efficiency results of Block C4 and competing techniques such as BZIP2 and ZIP for the Poly, Active, Contact, Metal1, Via1, and Metal2 layers of a complete industry 65 nm layout. Overall, we have found that compression efficiency varies

  18. Synthesis and Electrocatalytic Performance of Multi-Component Nanoporous PtRuCuW Alloy for Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    Xiaoting Chen

    2015-06-01

    Full Text Available We have prepared a multi-component nanoporous PtRuCuW (np-PtRuCuW electrocatalyst via a combined chemical dealloying and mechanical alloying process. The X-ray diffraction (XRD, transmission electron microscopy (TEM and electrochemical measurements have been applied to characterize the microstructure and electrocatalytic activities of the np-PtRuCuW. The np-PtRuCuW catalyst has a unique three-dimensional bi-continuous ligament structure and the length scale is 2.0 ± 0.3 nm. The np-PtRuCuW catalyst shows a relatively high level of activity normalized to mass (467.1 mA mgPt−1 and electrochemically active surface area (1.8 mA cm−2 compared to the state-of-the-art commercial PtC and PtRu catalyst at anode. Although the CO stripping peak of np-PtRuCuW 0.47 V (vs. saturated calomel electrode, SCE is more positive than PtRu, there is a 200 mV negative shift compared to PtC (0.67 V vs. SCE. In addition, the half-wave potential and specific activity towards oxygen reduction of np-PtRuCuW are 0.877 V (vs. reversible hydrogen electrode, RHE and 0.26 mA cm−2, indicating a great enhancement towards oxygen reduction than the commercial PtC.

  19. Novel Flow Field with Superhydrophobic Gas Channels Prepared by One-step Solvent-induced Crystallization for Micro Direct Methanol Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    Junsheng Liang; Kuanyao Liu; Shouzuo Li; Dazhi Wang; Tongqun Ren; Xiaoying Xu; Ying Luo

    2015-01-01

    The CO2-induced capillary blocking in anode flow field is one of the key adverse factors to reduce the performance of a micro-direct methanol fuel cell (lDMFC). In order to solve this problem, new polycarbonate (PC) flow field plates with nested arrangement of hydrophilic fuel channels and superhydrophobic gas channels were designed, fabricated, and tested in this work. The gas channels were treated with solvent-induced crystallization using acetone solution. The superhydrophobicity with 160? water contact angle and 2? tilting angle was obtained on the PC substrates. A dummy cell using hydrogen peroxide decomposition reaction and a test loop were separately set up to evaluate the flow fields’ performance. It was found that a 37% pressure drop decrease can be obtained in the new serpentine flow field compared with that of the conventional one. The benefit of the new flow field to remove gas bubbles was also confirmed by an in situ visualization study on the dummy cell. Results show that the auxiliary superhydrophobic gas channels can speed up the discharge of the gas bubbles from the flow field, which will in turn improve the lDMFC performance.

  20. Preparation of Pt-Re/Vulcan carbon nanocomposites using a single-source molecular precursor and relative performance as a direct methanol fuel cell electrooxidation catalyst.

    Science.gov (United States)

    Anderson, Angela D; Deluga, Gregg A; Moore, Joshua T; Vergne, Matthew J; Hercules, David M; Kenik, Edward A; Lukehart, C M

    2004-09-01

    Pt-Re/Vulcan carbon powder nanocomposites have been prepared with total metal loadings of 18 wt.% and 40 wt.% using a new non-cluster (1:1)-PtRe bimetallic precursor as the source of metal. Pt-Re nanoparticles having an average diameter of ca. 6 nm and atomic stoichiometry near 1:1 are formed. TEM, on-particle HR-EDS, and powder XRD data are consistent with the formation of Pt-Re alloy nanoparticles having a hexagonal unit cell with cell constants of a = 2.77 A and c = 4.47 A. A nanocomposite prepared at higher total metal loading under more rigorous thermal treatment also contains Pt-Re alloy nanoparticles having a fcc unit cell structure (a = 3.95 A). The precise dependence of Pt-Re nanocrystal structure on the thermal history of the nanocomposite specimen has not been investigated in detail. While these Pt-Re/carbon nanocomposites are active as anode catalysts in operating direct methanol fuel cells, the measured performance is less than that of commercial Pt-Ru/carbon catalysts and has marginal practical importance.

  1. Enhance performance of micro direct methanol fuel cell by in situ CO2 removal using novel anode flow field with superhydrophobic degassing channels

    Science.gov (United States)

    Liang, Junsheng; Luo, Ying; Zheng, Sheng; Wang, Dazhi

    2017-05-01

    Capillary blocking caused by CO2 bubbles in anode flow field (AFF) is one of the bottlenecks for performance improvement of a micro direct methanol fuel cell (μDMFC). In this work, we present a novel AFF structure with nested layout of hydrophilic fuel channels and superhydrophobic degassing channels which can remove most of CO2 from AFF before it is released to the fuel channels. The new AFFs are fabricated on Ti substrates by using micro photochemical etching combined with anodization and fluorination treatments. Performance of the μDMFCs with and without superhydrophobic degassing channels in their AFF is comparatively studied. Results show that the superhydrophobic degassing channels can significantly speed up the exhaust of CO2 from the AFF. CO2 clogging is not observed in the new AFFs even when their comparison AFFs have been seriously blocked by CO2 slugs under the same operating conditions. 55% and 60% of total CO2 produced in μDMFCs with N-serpentine and N-spiral AFF can be respectively removed by the superhydrophobic degassing channels. The power densities of the μDMFCs equipped with new serpentine and spiral AFFs are respectively improved by 30% and 90% compared with those using conventional AFFs. This means that the new AFFs developed in this work can effectively prevent CO2-induced capillary blocking in the fuel channels, and finally significantly improve the performance of the μDMFCs.

  2. Ni/Carbon Hybrid Prepared by Hydrothermal Carbonization and Thermal Treatment as Support for PtRu Nanoparticles for Direct Methanol Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    Marcelo Marques Tusi; Michele Brandalise; Nataly Soares de Oliveira Polanco; Olandir Vercino Correa; Antonio Carlos da Silva; Juan Carlo Villalba; Fauze Jaco Anaissi

    2013-01-01

    Ni/Carbon was prepared in two steps:initially cellulose as carbon source and NiCl2.6H20 as catalyst of the carbonization process were submitted to hydrothermal treatment at 200 ℃ and further to thermal treatment at 900 ℃ under argon atmosphere.The obtained material contains Ni nanoparticles with face-centered cubic (fcc) structure dispersed on amorphous carbon with graphitic domains.PtRu/C electrocatalysts (carbonsupported PtRu nanoparticles) were prepared by an alcohol-reduction process using Ni/Carbon as support.The materials were characterized by thermogravimetric analysis,energy-dispersive X-ray spectroscopy,Fourier transform infrared spectroscopy,X-ray diffraction,transmission electron microscopy and tested as anodes in single direct methanol fuel cell (DMFC).The performances of PtRu/C electrocatalysts using Ni/Carbon as support were superior to those obtained for PtRu/C using commercial carbon black Vulcan XC72 as support.

  3. A Three-Dimensional Two-Phase Flow Model for the Anode of Direct Methanol Fuel Cell%直接甲醇燃料电池阳极三维两相流模拟

    Institute of Scientific and Technical Information of China (English)

    吴玉厚; 田扬; 孙红; 左家骥

    2012-01-01

    目的 研究直接甲醇燃料电池阳极电化学反应和传质特性对其性能的重要影响.方法 建立一个直接甲醇燃料电池阳极三维两相流模型,分析电池阳极中甲醇和CO2的分布规律,以及电池温度和甲醇通入流速对电池阳极中甲醇质量浓度和CO2质量浓度分布的影响.结果 分析结果表明沿着流道方向,甲醇质量浓度降低,而CO2质量浓度升高;流场脊下甲醇和CO2的质量浓度低于流道下甲醇和CO2的质量浓度;升高电池温度,电化学反应加快,甲醇质量浓度降低而CO2质量浓度升高;增大甲醇通入流速,CO2质量浓度升高.结论 电池的电化学反应及流场结构决定了传质在电池中的质量浓度分布;电池的电化学反应速率受电池温度与甲醇通入流速的影响.研究结果对优化直接甲醇燃料电池操作参数,提高电池性能具有重要意义.%The paper aims to study the influence on the performance with electrochemical reaction and the mass transfer characteristics in the anode of direct methanol fuel cell. A three-dimensional two-phase flow model for the anode of direct methanol fuel cell is established to analyze the distribution of methanol and CO2 in the anode of fuel cell as well as the effect of fuel cell temperature and methanol inlet velocity on the distribution of methanol and CO2 concentration in anode. The results indicate that the methanol concentration decreases while the CO2 concentration elevated along the channel direction;the mass concentration of methanol and CO2 under the channel is lower than that under the flow ridge;if the fuel cell temperature increases, the electrochemical reaction would be accelerated and methanol concentration would decreased while CO2 concentration elevated; increase of the methanol access velocity would elevated the mass concentration of CO2. It is showed in this paper that the mass concentration distribution of transfer in the cell is determined by cell

  4. Ancillary Frequency Control of Direct Drive Full-Scale Converter Based Wind Power Plants

    DEFF Research Database (Denmark)

    Hu, Weihao; Su, Chi; Fang, Jiakun;

    2013-01-01

    This paper presents a simulation model of a wind power plant based on a MW-level variable speed wind turbine with a full-scale back-to-back power converter developed in the simulation tool of DIgSILENT Power Factory. Three different kinds of ancillary frequency control strategies, namely inertia ...

  5. Application of the direct simulation Monte Carlo method to the full shuttle geometry

    Science.gov (United States)

    Bird, G. A.

    1990-01-01

    A new set of programs has been developed for the application of the direct simulation Monte Carlo (or DSMC) method to rarefied gas flows with complex three-dimensional boundaries. The programs are efficient in terms of the computational load and also in terms of the effort required to set up particular cases. This efficiency is illustrated through computations of the flow about the Shuttle Orbiter. The general flow features are illustrated for altitudes from 170 to 100 km. Also, the computed lift-drag ratio during re-entry is compared with flight measurements.

  6. Directional view method for a time-sequential autostereoscopic display with full resolution.

    Science.gov (United States)

    Zhuang, Zhenfeng; Zhang, Lei; Surman, Phil; Guo, Song; Cao, Bin; Zheng, Yuanjin; Sun, Xiao Wei

    2016-10-01

    A time-sequential autostereoscopic three-dimensional (3D) display using a set of cylindrical optical elements (COEs) as the backlight steering is proposed. The operation principle of the system and its detailed design are described. In our system, the COEs control the direction of the backlight for the proposed system of the user's right and left views. Additionally, the displayed images can be observed under ambient lighting by implementing the high density light-emitting diode (LED) arrays. Compared to the first-generation array display, the image resolution is greatly improved by the addition of the time multiplexing technique. A prototype system using a set of COEs, LED arrays, two linear Fresnel lenses, and an elliptical diffuser is constructed. Here, the directional backlight beams are synchronized with the right and left images alternately displayed on the liquid crystal display (LCD) screen, and two convergent viewing zones are formed alternately in front of the user's eyes; then 3D images are perceived because of persistence of the vision of human eye. The experimental results show that the proposed method is a potential technology for 3D applications such as 3D television.

  7. Direct Strain Tensor Approximation for Full-Field Strain Measurement Methods

    Science.gov (United States)

    2013-01-01

    of grating coordinates using correlation filter techniques. Optik 1988; 80:76–79. 3. Bruck H, McNeill S, Sutton M, Peters W. Digital image correlation...record.url?eid=2-s2.0-46949097860&partnerID=40&md5= 25dddce389c9640db7cf8fbf3c50dc4e. 27. Cheng P, Sutton M, Schreier H, McNeill S. Full-field speckle

  8. Direct Polishing of Full-Shell, High-Resolution X-Ray Optics

    Science.gov (United States)

    Roche, Jacqueline M.; Gubarev, Mikhail V.; Smith, W. Scott; O'Dell, Stephen L.; Kolodziejczak, Jeffrey J.; Weisskopf, Martin C.; Ramsey, Brian D.; Elsner, Ronald F.

    2014-01-01

    Future x-ray telescopes will likely require lightweight mirrors to attain the large collecting areas needed to accomplish the science objectives. Understanding and demonstrating processes now is critical to achieving sub-arcsecond performance in the future. Consequently, designs not only of the mirrors but of fixtures for supporting them during fabrication, metrology, handling, assembly, and testing must be adequately modeled and verified. To this end, MSFC is using finite-element modeling to study the effects of mounting on thin, full-shell grazing-incidence mirrors, during all processes leading to a flight.

  9. Thermal Conductivity of Straw Bales: Full Size Measurements Considering the Direction of the Heat Flow

    Directory of Open Access Journals (Sweden)

    Jean-Philippe Costes

    2017-02-01

    Full Text Available The thermal conductivity of straw bales is an intensively discussed topic in the international straw bale community. Straw bales are, by nature, highly heterogeneous and porous. They can have a relatively large range of density and the baling process can influence the way the fibres are organised within the bale. In addition, straw bales have a larger thickness than most of the insulating materials that can be found in the building industry. Measurement apparatus is usually not designed for such thicknesses, and most of the thermal conductivity values that can be found in the literature are defined based on samples in which the straw bales are resized. During this operation, the orientation of the fibres and the density may not be preserved. This paper starts with a literature review of straw bale thermal conductivity measurements and presents a measuring campaign performed with a specific Guarded Hot Plate, designed to measure samples up to 50 cm thick. The influence of the density is discussed thoroughly. Representative values are proposed for a large range of straw bales to support straw-bale development in the building industry.

  10. Accidental methanol ingestion: Case report

    Directory of Open Access Journals (Sweden)

    Bakker Jan

    2010-02-01

    Full Text Available Abstract Background The incidence of methanol (CH3OH intoxication differs enormously from country to country. Methanol intoxication is extremely rare in the Dutch population. Even a low dose can already be potentially lethal. Patients are conventionally treated with hemodialysis. Therefore we'd like to present a report of a foreign sailor in Rotterdam who accidentally caused himself severe methanol intoxication, with a maximum measured concentration of 4.4 g/L. Case presentation The patient presented with hemodynamic instability and severe metabolic acidosis with pH 6.69. The anion gap was 39 mmol/L and the osmol gap 73 mosmol/kg. Treatment with ethanol and continuous venovenous hemodiafiltration (CVVH-DF was initiated. Despite the hemodynamic instability it is was possible to achieve rapid correction of pH and methanol concentration with CVVH-DF while maintaining a stable and therapeutic ethanol serum concentration. Despite hemodynamic and acid-base improvement, our patient developed massive cerebral edema leading to brain death. Permission for organ donation was unfortunately not ascertained. Conclusions We conclude that in a hemodynamic instable situation high methanol concentrations and methanol-induced derangements of homeostasis are safely and effectively treated with CVVH-DF and that severe cerebral edema is another possible cause of death rather than the classical bleeding in the putamen area.

  11. Application prospect of direct methanol fuel cell in communicative base station%直接甲醇燃料电池在通信基站的应用前景展望

    Institute of Scientific and Technical Information of China (English)

    孟彦伟

    2015-01-01

    In this paper, through the analysis of the characteristics of the direct methanol fuel cell itself, its usage prospect in communicative base station would be discussed herein.%本文通过对直接甲醇燃料电池本身的特性特点进行分析,并对其在通信基站的使用前景进行了展望。

  12. A Novel Design of Direct Methanol Fuel Cell for Notebook Computer%一种新型笔记本电脑用直接甲醇燃料电池的设计

    Institute of Scientific and Technical Information of China (English)

    王建萍

    2010-01-01

    简述一种新型笔记本电脑用直接甲醇燃料电池(Direct Methanol Fuel Cell,DMFC)的设计,介绍了电池的组成及其零部件的结构特点.该设计具有结构简单、加注燃料方便、排气功能好等优点.

  13. SEMICONDUCTOR INTEGRATED CIRCUITS: A self-adaptive full asynchronous bi-directional transmission channel for network-on-chips

    Science.gov (United States)

    Xuguang, Guan; Yintang, Yang; Zhangming, Zhu; Duan, Zhou

    2010-08-01

    To improve two shortcomings of conventional network-on-chips, i.e. low utilization rate in channels between routers and excessive interconnection lines, this paper proposes a full asynchronous self-adaptive bi-directional transmission channel. It can utilize interconnection lines and register resources with high efficiency, and dynamically detect the data transmission state between routers through a direction regulator, which controls the sequencer to automatically adjust the transmission direction of the bi-directional channel, so as to provide a flexible data transmission environment. Null convention logic units are used to make the circuit quasi-delay insensitive and highly robust. The proposed bi-directional transmission channel is implemented based on SMIC 0.18 μm standard CMOS technology. Post-layout simulation results demonstrate that this self-adaptive bi-directional channel has better performance on throughput, transmission flexibility and channel bandwidth utilization compared to a conventional single direction channel. Moreover, the proposed channel can save interconnection lines up to 30% and can provide twice the bandwidth resources of a single direction transmission channel. The proposed channel can apply to an on-chip network which has limited resources of registers and interconnection lines.

  14. Ru-decorated Pt nanoparticles on N-doped multi-walled carbon nanotubes by atomic layer deposition for direct methanol fuel cells

    DEFF Research Database (Denmark)

    Johansson, Anne-Charlotte Elisabeth Birgitta; Yang, R.B.; Haugshøj, K.B.

    2013-01-01

    (methylcyclopentadienyl)platinum MeCpPtMe3, bis(ethylcyclopentadienyl)ruthenium Ru(EtCp)2 and O2 as the precursors. Catalysts with 5, 10 and 20 ALD Ru cycles grown onto the CNT-supported ALD Pt nanoparticles (150 cycles) were prepared and tested towards the electro-oxidation of CO and methanol, using cyclic voltammetry...

  15. Endogenous methanol regulates mammalian gene activity.

    Directory of Open Access Journals (Sweden)

    Tatiana V Komarova

    Full Text Available We recently showed that methanol emitted by wounded plants might function as a signaling molecule for plant-to-plant and plant-to-animal communications. In mammals, methanol is considered a poison because the enzyme alcohol dehydrogenase (ADH converts methanol into toxic formaldehyde. However, the detection of methanol in the blood and exhaled air of healthy volunteers suggests that methanol may be a chemical with specific functions rather than a metabolic waste product. Using a genome-wide analysis of the mouse brain, we demonstrated that an increase in blood methanol concentration led to a change in the accumulation of mRNAs from genes primarily involved in detoxification processes and regulation of the alcohol/aldehyde dehydrogenases gene cluster. To test the role of ADH in the maintenance of low methanol concentration in the plasma, we used the specific ADH inhibitor 4-methylpyrazole (4-MP and showed that intraperitoneal administration of 4-MP resulted in a significant increase in the plasma methanol, ethanol and formaldehyde concentrations. Removal of the intestine significantly decreased the rate of methanol addition to the plasma and suggested that the gut flora may be involved in the endogenous production of methanol. ADH in the liver was identified as the main enzyme for metabolizing methanol because an increase in the methanol and ethanol contents in the liver homogenate was observed after 4-MP administration into the portal vein. Liver mRNA quantification showed changes in the accumulation of mRNAs from genes involved in cell signalling and detoxification processes. We hypothesized that endogenous methanol acts as a regulator of homeostasis by controlling the mRNA synthesis.

  16. 从超临界二氧化碳和甲醇直接合成碳酸二甲酯%DIRECT SYNTHESIS OF DIMETHYL CARBONATE FROM SUPERCRITICAL CARBON DIOXIDE AND METHANOL

    Institute of Scientific and Technical Information of China (English)

    赵天生; 韩怡卓; 孙予罕; 杨彩虹; 李文彬

    1999-01-01

    @@ Dimethyl carbonate (DMC), an environmentally benign intermediate for organic synthesis, has been mainly synthesized through non-phosgene route of oxidative carbonylation[1]. Direct synthesis of DMC from carbon dioxide and methanol is of more significance due to atom economy. Organometallic compounds of formulae R2M(OR)2, M(OR)2 or M(OR)4[2,3] were employed as catalysts in direct synthesis of DMC, where an activation mechanism of CO2 insertion into metal-oxygen bond was supposed. Unfortunately, the yield of DMC was low even in the presence of chemical dehydrants because mainly of thermodynamic limit.

  17. Surface-modified Nafion membranes with mesoporous SiO 2 layers via a facile dip-coating approach for direct methanol fuel cells

    Science.gov (United States)

    Lin, Yuhan; Li, Haidong; Liu, Changpeng; Xing, Wei; Ji, Xiangling

    In this study, Nafion ® 117 membrane is surface-modified with mesoporous silica layers through in situ surfactant-templated sol-gel reaction. The reaction makes use of tetraethyl orthosilicate (TEOS) under acidic condition via dip-coating technique on both sides. Scanning electron microscopy (SEM), Fourier transformation infrared (FTIR), and thermogravimetric analysis (TGA) are employed to characterize the resultant membranes. Proton conductivity and methanol permeability of the membranes are also studied. It is determined that the aging time, along with the number of the silicon dioxide (SiO 2) layer, influence both proton conductivity and methanol permeability. Specifically, double-side modified membrane with 5 min interval of the second layer (S (5)) exhibits optimal properties on the combined criterion of conductivity and permeability. However, the application of mesoporous silica layer in modifying commercial Nafion membranes through dip-coating is proven to be a facile route in improving the said criteria simultaneously.

  18. Full-length RecE enhances linear-linear homologous recombination and facilitates direct cloning for bioprospecting.

    Science.gov (United States)

    Fu, Jun; Bian, Xiaoying; Hu, Shengbaio; Wang, Hailong; Huang, Fan; Seibert, Philipp M; Plaza, Alberto; Xia, Liqiu; Müller, Rolf; Stewart, A Francis; Zhang, Youming

    2012-05-01

    Functional analysis of genome sequences requires methods for cloning DNA of interest. However, existing methods, such as library cloning and screening, are too demanding or inefficient for high-throughput application to the wealth of genomic data being delivered by massively parallel sequencing. Here we describe direct DNA cloning based on the discovery that the full-length Rac prophage protein RecE and its partner RecT mediate highly efficient linear-linear homologous recombination mechanistically distinct from conventional recombineering mediated by Redαβ from lambda phage or truncated versions of RecET. We directly cloned all ten megasynthetase gene clusters (each 10–52 kb in length) from Photorhabdus luminescens into expression vectors and expressed two of them in a heterologous host to identify the metabolites luminmycin A and luminmide A/B. We also directly cloned cDNAs and exactly defined segments from bacterial artificial chromosomes. Direct cloning with full-length RecE expands the DNA engineering toolbox and will facilitate bioprospecting for natural products.

  19. 直接甲醇燃料电池钯基催化剂研究进展%Research Progress in Pd Based Catalysts for Direct Methanol Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    王丽; 杨云裳; 裴春娟

    2014-01-01

    直接甲醇燃料电池(DMFC)阳极催化剂是直接甲醇燃料电池的关键材料之一。由于钯的价格便宜、储量丰富、在碱性条件下活性较高,成为取代铂作为DMFC的潜在的阳极催化剂。着重介绍了近年来钯基阳极催化剂在碱性条件下对甲醇的电氧化的研究进展,展望了其发展前景。%The anode catalyst is one of the key materials for direct methanol fuel cell (DMFC). Pd is more suitable than Pt as a kind of anode catalyst due to its relatively low cost and abundance on the earth. In this paper, Pd-based catalysts for electro-oxidation of methanol in alkaline media were reviewed, and the development of the catalysts for methanol electro-oxidation was prospected.

  20. Pd and Pt-Ru anode electrocatalysts supported on multi-walled carbon nanotubes and their use in passive and active direct alcohol fuel cells with an anion-exchange membrane (alcohol = methanol, ethanol, glycerol)

    Science.gov (United States)

    Bambagioni, Valentina; Bianchini, Claudio; Marchionni, Andrea; Filippi, Jonathan; Vizza, Francesco; Teddy, Jacques; Serp, Philippe; Zhiani, Mohammad

    Palladium and platinum-ruthenium nanoparticles supported on multi-walled carbon nanotubes (MWCNT) are prepared by the impregnation-reduction procedure. The materials obtained, Pd/ MWCNT and Pt-Ru/ MWCNT, are characterized by TEM, ICP-AES and XRPD. Electrodes coated with Pd/ MWCNT are scrutinized for the oxidation of methanol, ethanol or glycerol in 2 M KOH solution in half cells. The catalyst is very active for the oxidation of all alcohols, with glycerol providing the best performance in terms of specific current density and ethanol showing the lowest onset potential. Membrane-electrode assemblies have been fabricated using Pd/ MWCNT anodes, commercial cathodes and anion-exchange membrane and evaluated in both single passive and active direct alcohol fuel cells fed with aqueous solutions of 10 wt.% methanol, 10 wt.% ethanol or 5 wt.% glycerol. Pd/ MWCNT exhibits unrivalled activity as anode electrocatalyst for alcohol oxidation. The analysis of the anode exhausts shows that ethanol is selectively oxidized to acetic acid, detected as acetate ion in the alkaline media of the reaction, while methanol yields carbonate and formate. A much wider product distribution, including glycolate, glycerate, tartronate, oxalate, formate and carbonate, is obtained from the oxidation of glycerol. The results obtained with Pt-Ru/ MWCNT anodes in acid media are largely inferior to those provided by Pd/ MWCNT electrodes in alkaline media.

  1. METHANOL REMOVAL FROM METHANOL-WATER MIXTURE USING ACTIVATED SLUDGE, AIR STRIPPING AND ADSORPTION PROCESS: COMPARATIVE STUDY

    Directory of Open Access Journals (Sweden)

    SALAM K. AL-DAWERY

    2015-12-01

    Full Text Available An experimental research has been carried out in order to examine the removal of methanol from methanol-water mixtures using three different methods; activated sludge; activated carbon and air stripping. The results showed that the methanol was totally consumed by the bacteria as quickly as the feed entered the activated sludge vessel. Air stripping process has a limited ability for removing of methanol due to strong intermolecular forces between methanol and water; however, the results showed that the percentage of methanol removed using air pressure at 0.5 bar was higher than that of using air pressure of 0.25 bar. Removal of methanol from the mixture with a methanol content of 5% using activated carbon was not successful due to the limited capacity of the of the activated carbon. Thus, the activated sludge process can be considered as the most suitable process for the treatment of methanol-water mixtures.

  2. Proton-exchange sulfonated poly(ether ether ketone)(SPEEK)/SiOx-s composite membranes in direct methanol fuel cells%DMFCs用SPEEK/SiOx-S复合质子交换膜

    Institute of Scientific and Technical Information of China (English)

    高启君; 王宇新; 许莉; 卫国强; 王志涛

    2009-01-01

    A sulfonated poly(ether ether ketone)(SPEEK)membrane with a fairly high degree of SUl fonation (DS)can swell excessively and even dissolve at high temperature.To solve these problems,insolvable functionalized silica powder with suIlbnic acid groups(SiOx-S)was added into the SPEEK matrix(DS=55.1%) to prepare SPEEK/SiOx-S composite membranes.The decrease in both the swelling degree and the methanol permeability of the membranes was a dose-dependent result of addition of the SiOx-S powder.Pure SPEEK membrane swelled 52.6%at 80°C,whereas the SPEEK/SiOx-S(1 5%,by mass)membrane swelled only 27.3%at the same temperature.From room temperature to 80℃,all SPEEK/SPEEK/SiOx-S composite membranes had methanol petea-bility of about one order of magnitude lower than that of Nafion r 115.Compared with pure SPEEK membranes,the addition of the SiOx-S powder not only leads to higher proton conductivity,but also increascs the dimensional stability at higher temperatures,and grcater proton conductivity can bc achieved at higher temperature.The SPEEK/SiOx-S(20%,by mass)membrane could withstand temperature up to 145°C,at which in 100%relative humidity(RH) its proton branc dissolved at 90°C.The SPFEk/SiOx-S composite membranes are promising for use in direct methanol fuel cells because of their good dimensional stability,high proton conductivity,and low methanol permeability.

  3. Recycling of greenhouse gases via methanol

    Energy Technology Data Exchange (ETDEWEB)

    Bill, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Eliasson, B.; Kogelschatz, U. [ABB Corporate Research Center, Baden-Daettwil (Switzerland)

    1997-06-01

    Greenhouse gas emissions to the atmosphere can be mitigated by using direct control technologies (capture, disposal or chemical recycling). We report on carbon dioxide and methane recycling with other chemicals, especially with hydrogen and oxygen, to methanol. Methanol synthesis from CO{sub 2} is investigated on various catalysts at moderate pressures ({<=}30 bar) and temperatures ({<=}300{sup o}C). The catalysts show good methanol activities and selectivities. The conversion of CO{sub 2} and CH{sub 4} to methanol is also studied in a silent electrical discharge at pressures of 1 to 4 bar and temperatures close to room temperature. Methanol yields are given for mixtures of CO{sub 2}/H{sub 2}, CH{sub 4}/O{sub 2} and also for CH{sub 4} and air mixtures. (author) 2 figs., 5 refs.

  4. New catalysts for miniaturized methanol fuel cells

    DEFF Research Database (Denmark)

    Pedersen, Christoffer Mølleskov

    The methanol fuel cell is an interesting energy technology, capable of converting the chemical energy of methanol directly into electricity. The technology is specifically attractive for small mobile applications such as laptops, smartphones, tablets etc. since it offers almost instantaneously...... recharging by simply replacing the methanol liquid. The technology is currently being developed for hearing instruments in order to ease the handling of the device for users complaining about difficulties replacing the very small batteries in the hearing instrument. The technology has already been...... and methanol poisoning of the oxygen reduction are studied. Consequently, promising new candidates for replacing the standard catalyst are identified. One of these, Pt5Gd, exhibits improved oxygen reduction reaction activity even in the presence of methanol, thus making Pt5Gd an interesting candidate...

  5. 不同蛇形流场下的直接甲醇燃料电池性能及阻抗分析%Performance and Impedance Analysis of Direct Methanol Fuel Cell under Different Serpentine Flow Field

    Institute of Scientific and Technical Information of China (English)

    吴玉厚; 田扬; 孙红; 万烨

    2013-01-01

    The performances and impedances of direct methanol fuel cells with single channel serpentine flow field and multichannel serpentine flow field are studied. The VA( volt-ampere) characteristics and AC(alternating-current) impedance of serpentine flow field methanol fuel cell are measured in this experiment, and the effects of the flow field structure, methanol concentration and its flow velocity on the VA characteristics and AC impedance are analyzed. The experimental results show that the performance of multichannel serpentine flow field methanol fuel cell is better than that of the single channel serpentine flow field methanol fuel cell. The ohmic resistance and electrode reaction impedance of the methanol fuel cell with the multichannel serpentine flow field are small by the analysis of the AC impedance with equivalent circuit. The characteristic of the electric double layer is close to resistance characteristics in the methanol fuel cell with multichannel serpentine flow field. These results are very helpful to optimize the methanol fuel cell performance and its e-lectrode structure.%目的 研究不同实验条件下单通道蛇形流场与多通道蛇形流场直接甲醇燃料电池的性能差异与阻抗变化.方法 实验测量了蛇形流场甲醇燃料电池的伏安特性和交流阻抗,分析了流场结构、甲醇浓度和流速对电池伏安特性和交流阻抗的影响.结果 实验结果表明:多通道蛇形流场甲醇燃料电池的性能优于单通道蛇形流场甲醇燃料电池.通过等效电路分析其交流阻抗发现:多通道蛇形流场甲醇燃料电池的欧姆阻抗、电极反应阻抗都比较小;多通道蛇形流场甲醇燃料电池电极形成的双电层特性趋近电阻特性.结论 阻抗的变化是决定多通道蛇形流场甲醇燃料电池性能高于单通道蛇形流场甲醇燃料电池的重要原因.研究结果对甲醇燃料电池性能和电极优化提供了有益的参考.

  6. 磺化皂土改性直接甲醇燃料电池用Nafion膜%Sulfonated bentonite modified Nafion membrane for direct methanol fuel cell

    Institute of Scientific and Technical Information of China (English)

    田哲; 刘桂成; 王萌; 王新东

    2013-01-01

    A novel proton exchange membrane with lower methanol permeation was prepared by doping sulfonated bentonite and tetraethyl orthosilicate (TEOS)into Nafion 212 membrane by sol-gel method.The proton conductivity and methanol permeability coefficient of modified membrane and Nafion 212 were studied by chronoamperometey and AC impedance tests.It showed that the methanol permeability coefficient of modified membrane decreased by 86% compared with Nafion 212 membrane,and the modified membrane also had a good proton conductivity which reached to 69.6 mS/cm.It was indicated by the cell tests that the membrane electrode assembly(MEA) prepared with modified membrane got better performance under the situation of relatively high temperature.The methanol crossover of MEA with modified membrane was significantly lower,which decreased respectively 67.7 mA/cm2 and 61.5 mA/cm2 under the different temperatures of 30℃ and 55℃.%以磺化皂土和正硅酸乙酯(TEOS)为掺杂物,采用溶胶-凝胶法掺杂改性Nafion 212膜,并制成膜电极组件(MEA).通过计时电流、交流阻抗等测试,研究了Nafion 212膜改性前后的甲醇渗透系数、质子电导率及电池功率密度等.改性后的Nafion 212膜,甲醇渗透系数比改性前降低了86%,质子导电率达到69.6 mS/cm;单体电池性能和甲醇渗透电流测试发现:改性膜制备的MEA的甲醇渗透电流密度在30℃和55℃时分別比改性前降低67.7 mA/cm2和61.5 mA/cm2.

  7. Methylnaltrexone bromide methanol monosolvate

    Directory of Open Access Journals (Sweden)

    Xinbo Zhou

    2012-03-01

    Full Text Available In the title compound [systematic name: (4R,4aS,7aR,12bS-3-cyclopropylmethyl-4a,9-hydroxy-7-oxo-2,3,4,4a,5,6,7,7a-octahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinolin-3-ium bromide methanol monosolvate], C21H26NO4+·Br−·CH3OH, two of the three six-membered rings adopt chair conformations while the third, which contains a C=C double bond, adopts an approximate half-boat conformation. The 2,3-dihydrofuran ring adopts an envelope conformation. In the crystal, the components are linked by O—H...O and O—H...Br hydrogen bonds. The absolute stereochemistry was inferred from one of the starting materials.

  8. The Methanol Miracle

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    Methanol already makes a good fuel for camp stoves and even for a few cars. But in the future,say botanist Arthur Nonomura and biochemist Andrew Benson,methanol may fuel an agricultural revolution in hot and dry regions of the world. When the researchers recently sprayed diluted solutions of methanol on crops at Nonomura’s Arizona farm,they found they could double yields in some cases and halve water consumption in others.

  9. Methanol Asinger's vision today

    CERN Document Server

    Bertau, Martin; Plass, Ludolf; Schmidt, Friedrich; Wernicke, Hans-Jürgen

    2014-01-01

    Methanol - The Chemical and Energy Feedstock of the Future offers a visionary yet unbiased view of methanol technology. Based on the groundbreaking 1986 publication ""Methanol"" by Friedrich Asinger, this book includes contributions by more than 40 experts from industry and academia. The authors and editors provide a comprehensive exposition of methanol chemistry and technology which is useful for a wide variety of scientists working in chemistry and energy related industries as well as academic researchers and even decision-makers and organisations concerned with the future of chemical and e

  10. Preparation of main-chain-type and side-chain-type sulfonated poly(ether ether ketone) membranes for direct methanol fuel cell applications

    Science.gov (United States)

    Tsai, Jie-Cheng; Lin, Chien-Kung

    Novel main-chain-type and side-chain-type sulphonated poly(ether ether ketone)s (MS-SPEEKs) are synthesised by reacting the sulphonic acid groups of pristine SPEEKs with 2-aminoethanesulphonic acid to improve the nano-phase separated morphology of the material. 1H NMR and FT-IR spectroscopy are employed to determine the structure and composition of main-chain-type and side-chain-type sulphonated polymers. Flexible and tough membranes with reasonable thermal properties are obtained. The MS-SPEEKs show good hydrolytic stability, and water uptake values ranging from 15% to 30% are observed. Compared to Nafion 117 ®, the methanol permeability of the MS-SPEEKs is dramatically reduced to 8.83 × 10 -8 cm 2 s -1 to 3.31 × 10 -7 cm 2 s -1. The proton conductivity increases with increasing temperature, reaching 0.013-0.182 S cm -1. A maximum power density and open circuit voltage of 115 mW cm -2 and 0.830 V are obtained at 80 °C, respectively, which is significantly greater than the values generated with Nafion 117 ®. The introduction of pendent side-chain-type sulphonic acid groups increases the single-cell performance by more than approximately 20%; thus, the lower water diffusivity, methanol permeability, electro-osmotic drag coefficient and high cell performance indicated that MS-SPEEK is a promising candidate for DMFC applications.

  11. Heat and mass transfer characteristics in ducted air-breathing direct methanol fuel cells%空气抽吸式甲醇燃料电池传热与传质特性

    Institute of Scientific and Technical Information of China (English)

    唐蜜; 叶强

    2012-01-01

    空气抽吸式直接甲醇燃料电池不仅具有被动式燃料电池的优点,同时又便于将其串联成电堆提高输出电压.建立以阴极为管道抽吸式结构的直接甲醇燃料电池的三维、两相、非等温稳态数值模型,研究了质子交换膜性能、供给甲醇浓度以及电堆规模对电池性能及燃料利用率的影响.对于保温较好的大电堆,采用低甲醇穿透的改性质子交换膜能同时提升燃料利用率和比功率;此类电堆若采用穿透率低的改性膜,则2mol/L的甲醇浓度就能保证电池在较大的电流密度区间内维持较高的功率与效率.作为影响电池运行温度的重要因素,电堆规模的大小将直接影响质子交换膜种类与甲醇浓度等关键参数的设计与选择.%Ducted air-breathing direct methanol fuel cells (DMFC) not only has the advantages of passive fuel cells, but also can be assembled in series easily to raise the output voltage. A three dimensional, steady state, non-isothermal and steady numerical model has been developed for the ducted air-breathing DMFC. The effects of proton exchange membrane (PEM) properties, supplying methanol concentration and the size of cell stack on both the fuel efficiency and cell performance were investigated. The numerical results indicate that using the modified PEM with low methanol crossover, for large cell stack with good thermal insulation, can improve fuel efficiency and power density. High fuel efficiency and power density of such cell stack with modified PEM can be maintained in a wide current density range while using 2 mol/L methanol. As a key factor in determining cell temperature, stack size has great impact on designing and selecting other important parameters, such as PEM properties and methanol concentration.

  12. Investigation on the Bearing Abilities of Three-Dimensional Full Five-Directional Braided Composites with Cut-Edge

    Science.gov (United States)

    Wang, Yibo; Liu, Zhenguo; Lei, Bing; Huang, Xiang; Li, Xiaokang

    2016-11-01

    The longitudinal tensile experiments of cut-edge effect on the mechanical performance of three-dimensional full five-directional (3DF5D) braided composites were conducted. The specimens involved two different braiding angles and two different cutting ways. Fracture appearance of specimens without cut-edge and cutting along width direction presented flush, while explosive for specimen with cut-edge along thickness direction. The fracture of axis yarns mainly contributed to the damage of specimens. Cut-edge had little influence on the stiffness of 3DF5D braided composites and had approximately 20 % reduction in tensile strength compared with specimens without cut-edge. The periodic boundary conditions under cut-edge and uncut-edge situations were applied to the RVC to simulate the mesoscopic damage mechanism using finite element method. The stress-strain curves and damage evolution nephogram were obtained. The variation of cut-edge effect with the number of inner cells was predicted by superimposing inner cells method, the addition of inner cells could strengthen the performance of 3DF5D braided composites with cut-edge. These results will play an important role in evaluating the mechanical properties of braided materials after cutting.

  13. Implementation of air quality control in reproductive laboratories in full compliance with the Brazilian Cells and Germinative Tissue Directive.

    Science.gov (United States)

    Esteves, Sandro C; Bento, Fabiola C

    2013-01-01

    This article describes how Androfert complied with the Brazilian Cells and Germinative Tissue Directive with regard to air quality standards and presents retrospective data of intracytoplasmic sperm injection (ICSI) outcomes performed in controlled environments. An IVF facility, composed of reproductive laboratories, operating room and embryo-transfer room, was constructed according to cleanroom standards for air particles and volatile organic compounds. A total of 2060 couples requesting IVF were treated in the cleanroom facilities, and outcome measures compared with a cohort of 255 couples treated at a conventional facility from the same practice before implementation of cleanrooms. No major fluctuations were observed in the cleanroom validation measurements over the study period. Live birth rates increased (35.6% versus 25.8%; P=0.02) and miscarriage rates decreased (28.7% versus 20.0%; P=0.04) in the first triennium after cleanroom implementation. Thereafter, the proportion of high-quality embryos steadily increased whereas pregnancy outcomes after ICSI were sustained despite the increased female age and decreased number of embryos transferred. This study demonstrates the feasibility of handling human gametes and culturing embryos in full compliance with the Brazilian directive on air quality standards and suggests that performing IVF in controlled environments may optimize its outcomes. Regulatory agencies in many countries have issued directives including specific requirements for air quality standards in embryology facilities. This article describes how we complied with the Brazilian Cells and Germinative Tissue Directive with regard to air quality standards. It also presents results of IVF cycles performed in controlled environments. An IVF facility, composed of reproductive laboratories, operating room and embryo transfer room, was constructed according to cleanroom standards for air particles and volatile organic compounds. The cleanest area was the

  14. Research status of direct methanol fuel cell and current key problems%直接甲醇燃料电池研究现状及主要问题

    Institute of Scientific and Technical Information of China (English)

    李建玲; 毛宗强

    2001-01-01

    直接甲醇燃料电池(DMFC)具有燃料易运输与存储、重量轻、体积小、结构简单、能量效率高等优点,以固体聚合物作为电解质的直接甲醇燃料电池是理想的车用动力电源,具有广阔的发展前景。从DMFC性能研究、甲醇穿过Nafion膜渗透的影响、膜研究及电催化剂研究等四个方面描述了直接甲醇燃料电池的研究现状及存在的主要问题,结合当前的最新研究成果,给出DMFC研究中需要解决的几个关键问题。%Direct methanol fuel cells (DMFC) had several advantagesincluding ease transportation and storage of the fuel,reduced system weight,size and complexity,high energy efficiency.Polymer electrolyte membrane direct methanol fuel cells (PEMDMFC) were ideal power source for vehicles with bright prospects to be expected.The state-of-art and problems in the fields of DMFC performance,the impact of methanol crossover across the Nafion membrane,membrane and eletrocatalysts were described.Several key problems needed to be solved in the study of DMFC were suggested according to recent advances.

  15. High resolution aquifer characterization using crosshole GPR full-waveform tomography: Comparison with direct-push and tracer test data

    Science.gov (United States)

    Gueting, Nils; Vienken, Thomas; Klotzsche, Anja; van der Kruk, Jan; Vanderborght, Jan; Caers, Jef; Vereecken, Harry; Englert, Andreas

    2017-01-01

    Limited knowledge about the spatial distribution of aquifer properties typically constrains our ability to predict subsurface flow and transport. Here we investigate the value of using high resolution full-waveform inversion of cross-borehole ground penetrating radar (GPR) data for aquifer characterization. By stitching together GPR tomograms from multiple adjacent crosshole planes, we are able to image, with a decimeter scale resolution, the dielectric permittivity and electrical conductivity of an alluvial aquifer along cross sections of 50 m length and 10 m depth. A logistic regression model is employed to predict the spatial distribution of lithological facies on the basis of the GPR results. Vertical profiles of porosity and hydraulic conductivity from direct-push, flowmeter and grain size data suggest that the GPR predicted facies classification is meaningful with regard to porosity and hydraulic conductivity, even though the distributions of individual facies show some overlap and the absolute hydraulic conductivities from the different methods (direct-push, flowmeter, grain size) differ up to approximately one order of magnitude. Comparison of the GPR predicted facies architecture with tracer test data suggests that the plume splitting observed in a tracer experiment was caused by a hydraulically low-conductive sand layer with a thickness of only a few decimeters. Because this sand layer is identified by GPR full-waveform inversion but not by conventional GPR ray-based inversion we conclude that the improvement in spatial resolution due to full-waveform inversion is crucial to detect small-scale aquifer structures that are highly relevant for solute transport.

  16. Accuracy and repeatability of direct ciliary sulcus diameter measurements by full-scale 50-megahertz ultrasound biomicroscopy

    Institute of Scientific and Technical Information of China (English)

    LI De-jiao; WANG Ning-li; CHEN Shu; LI Shu-ning; MU Da-peng; WANG Tao

    2009-01-01

    Background Phakic intraocular lens (pIOL) implantation has been a popular means for the treatment of high ametropia. Measurements of ciliary sulcus diameter is important for pIOL size determining. But till now, no perfect system can directly measure it. The present study was to evaluate the accuracy, repeatability and reproducibility of direct sulcus diameter measurements obtained by a full-scale 50-megahertz (MHz) ultrasound biomicroscopy (UBM).Methods A fresh cadaver human eye with a scale marker inserted through the posterior chamber plane from 3 o'clock to 9 o'clock meridian and 30 randomly selected eyes from 30 normal subjects were scanned by full-scale 50-MHz UBM in horizontal meridional scan plane. The distance between the scales and the whole length of the marker inside the cadaver eye were measured by the same observer using the "built-in" measurement tools and the indicating error of instrument was calculated. Reproducibility of the measurement was evaluated in 30 eyes by 2 operators using Blander and Altman plot test. Repeatability was evaluated from 10 successive eyes randomly selected from the 30 eyes by one operator.Results On a scale of 1 mm, the greatest indicating error was 40 μm; the mean largest indicating error of 1 mm scale from the 10 images was (26±14) μm; on a scale of 11 mm, the greatest indicating error was 70 μo; the error rate was 0.64%. The mean length of the needle inside the eye of the 10 images was 11.05 mm, with the mean indicating error of 47 μm, the average error rate was 0.43%. For ciliary sulcus diameter measurements in vivo, the coefficient of variation was 0.38%; the coefficients of repeatability for intra-observer and inter-observer measurements were 1.99% and 2.55%, respectively. The limits of agreement for intra-observer and inter-observer measurement were-0.41 mm to 0.48 mm and -0.59 mm to 0.58 ram, respectively.Conclusion The full-scale 50-MHz UBM can be a high accuracy and good repeatability means for direct

  17. Performance of direct injection methanol engine using the fuel jet impingement and diffusion. ; Comparison between the spark plug and glow plug ignitions. Nenryo funryu no shototsu kakusan wo riyoshita chokufun methanol kikan no seino. ; Spark plug oyobi glow plug chakka hoshiki no hikaku

    Energy Technology Data Exchange (ETDEWEB)

    Kato, S.; Onishi, S.

    1993-01-20

    The purpose of this paper is to compare the performance of direct fuel injection methanol engines with the spark plug and glow plug ignition systems. These methanol engines utilize the formation of fuel-air mixture by the fuel jet impingement and diffusion. Engine performance and cylinder pressure for the both ignition systems were analyzed. Piezoelectric pressure indicator was used for the cylinder pressure measurements, and combustion analyzer was used for their analyses. In order to estimate engine performance, effects of load and engine speed were analyzed. Consequently, almost the same brake thermal efficiencies (maximum value of 42%) were obtained for both ignition systems. For the glow plug ignition system, the combustion noise and NOx emission were lower than the spark plug engine. The NOx emission did not excess 500ppm with the glow plug ignition system. In the impingement and diffusion method, both the piston attached type impingement part and cylinder head fixed type one were applicable. 4 refs., 9 figs., 2 tabs.

  18. Transesterification of waste vegetable oil under pulse sonication using ethanol, methanol and ethanol–methanol mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Guerra, Edith; Gude, Veera Gnaneswar, E-mail: gude@cee.msstate.edu

    2014-12-15

    Highlights: • Pulse sonication effect on transesterification of waste vegetable oil was studied. • Effects of ethanol, methanol, and alcohol mixtures on FAMEs yield were evaluated. • Effect of ultrasonic intensity, power density, and its output rates were evaluated. • Alcohol mixtures resulted in higher biodiesel yields due to better solubility. - Abstract: This study reports on the effects of direct pulse sonication and the type of alcohol (methanol and ethanol) on the transesterification reaction of waste vegetable oil without any external heating or mechanical mixing. Biodiesel yields and optimum process conditions for the transesterification reaction involving ethanol, methanol, and ethanol–methanol mixtures were evaluated. The effects of ultrasonic power densities (by varying sample volumes), power output rates (in W), and ultrasonic intensities (by varying the reactor size) were studied for transesterification reaction with ethanol, methanol and ethanol–methanol (50%-50%) mixtures. The optimum process conditions for ethanol or methanol based transesterification reaction of waste vegetable oil were determined as: 9:1 alcohol to oil ratio, 1% wt. catalyst amount, 1–2 min reaction time at a power output rate between 75 and 150 W. It was shown that the transesterification reactions using ethanol–methanol mixtures resulted in biodiesel yields as high as >99% at lower power density and ultrasound intensity when compared to ethanol or methanol based transesterification reactions.

  19. 直接甲醇燃料电池堆结构及活化的研究进展%Research progress of structure and activation of direct methanol fuel

    Institute of Scientific and Technical Information of China (English)

    王松清; 陈胜洲; 叶飞; 林维明

    2011-01-01

    直接甲醇燃料电池(DMFC)具有高比能量和更换燃料方便等优点,被认为是最有希望应用于便携电子产品(如笔记本电脑、手机、数码相机)的移动电源之一.介绍了直接甲醇燃料电池的工作原理以及活化方法,重点综述了直接甲醇燃料电池堆结构的进展,展望了未来直接甲醇燃料电池堆的研究方向.%Direct methanol fuel cells (DMFC) are regarded as one of the most promising candidates for powering portable electronic devices, such as laptops, cellular phones and digital still camera because of the advantages of high energy density and convenience in refueling. The working principle of DMFC and its activation method was introduced, the recent research development of direct methanol fuel cells stack structure was reviewed in detail, and the future research work on structure was proposed.

  20. Hydrostratigraphic analysis of the MADE site with full-resolution GPR and direct-push hydraulic profiling

    Science.gov (United States)

    Dogan, M.; Van Dam, R. L.; Bohling, G.C.; Butler, J.J.; Hyndman, D.W.

    2011-01-01

    Full-resolution 3D Ground-Penetrating Radar (GPR) data were combined with high-resolution hydraulic conductivity (K) data from vertical Direct-Push (DP) profiles to characterize a portion of the highly heterogeneous MAcro Dispersion Experiment (MADE) site. This is an important first step to better understand the influence of aquifer heterogeneities on observed anomalous transport. Statistical evaluation of DP data indicates non-normal distributions that have much higher similarity within each GPR facies than between facies. The analysis of GPR and DP data provides high-resolution estimates of the 3D geometry of hydrostratigraphic zones, which can then be populated with stochastic K fields. The lack of such estimates has been a significant limitation for testing and parameterizing a range of novel transport theories at sites where the traditional advection-dispersion model has proven inadequate. ?? 2011 by the American Geophysical Union.

  1. Methanol partial oxidation reformer

    Science.gov (United States)

    Ahmed, Shabbir; Kumar, Romesh; Krumpelt, Michael

    1999-01-01

    A partial oxidation reformer comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell.

  2. Full-vectorial finite-difference beam propagation method based on the modified alternating direction implicit method

    Institute of Scientific and Technical Information of China (English)

    Xiao Jin-Biao; Sun Xiao-Han

    2006-01-01

    A modified alternating direction implicit algorithm is proposed to solve the full-vectorial finite-difference beam propagation method formulation based on H fields. The cross-coupling terms are neglected in the first sub-step, but evaluated and doubly used in the second sub-step. The order of two sub-steps is reversed for each transverse magnetic field component so that the cross-coupling terms are always expressed in implicit form, thus the calculation is very efficient and stable. Moreover, an improved six-point finite-difference scheme with high accuracy independent of specific structures of waveguide is also constructed to approximate the cross-coupling terms along the transverse directions. The imaginary-distance procedure is used to assess the validity and utility of the present method. The field patterns and the normalized propagation constants of the fundamental mode for a buried rectangular waveguide and a rib waveguide are presented. Solutions are in excellent agreement with the benchmark results from the modal transverse resonance method.

  3. Application of Three Unit-Cells Models on Mechanical Analysis of 3D Five-Directional and Full Five-Directional Braided Composites

    Science.gov (United States)

    Zhang, Chao; Xu, Xiwu; Chen, Kang

    2013-10-01

    As new lightweight textile material, 3D five directional and full five directional braided composites (5DBC and F5DBC) have tremendous potential applications in the aerospace industry. Before they are used in primary loading-bearing structures, a rational characterization of their mechanical properties is essential. In this paper, three types of unit-cell models corresponding to the interior, surface and corner regions of 5DBC and F5DBC are proposed. By introducing the reasonable boundary conditions, the effective stiffness properties of these two materials are predicted and compared by the three unit-cells models. The detailed mechanical response characteristic of the three unit-cell models is presented and analyzed in various loading cases. Numerical results show good agreement with experiment data, thus validates the proposed simulation method. Moreover, a parametric study is carried out for analyzing the effects of braiding angle and fiber volume fraction on the elastic properties of 5DBC and F5DBC. The obtained results can help designers to optimize the braided composite structures.

  4. 一种微型直接甲醇燃料电池的制作与测试%The Design and Fabrication of a Micro Direct Methanol Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    曾毅波; 刘俊; 陈观生; 郭航

    2012-01-01

    Micro direct methanol fuel cell (fi-DMFC)with the virtue of high power efficiency,few-environmental pollution,safety and portable has a great prospect of application in small civilian power and individual portable power. The characteristic of μ-DMFC (micro direct methanol fuel cell) is discussed. Then,with the process of micro-electro-mechanical systems (MEMS),the process that the fi-DMFC is designed and fabricated is researched. Firstly,the flow-field plate of μ-DMFC is fabricated by process of MEMS. Secondly,the membrane electrode assembly(MEA) is prepared. Then,the package structure of fi-DMFC is improved,the polydimethylsilox-anef (PDMS) and metal fixture are adopted to package the fi-DMFC, which avoids leakage of methanol effectively. Finally, the IV property of fi-DMFC is tested. The electrical property of fi-DMFC is compared on the different structure of package. The result shows that on the μ-DMFC of improved package structure,the maximum current density is 14. 82 mA/cm2 ,and the maximum output power is 0. 661 mW.%微型直接甲醇燃料电池(micro direct methanol fuel cell,μ-DMFC)具有发电效率高、环境污染少、安全、携带方便等优点,在小型民用电源和单兵携带电源上具有广泛的应用.讨论了微型直接甲醇燃料电池(micro direct methanol fuel cell,μ-DMFC)的特点,研究了运用微机电系统(micro-electro-mechanical systems,MEMS)工艺,设计并且制作μ-DMFC的过程.主要是运用MEMS 工艺制作μ-DMFC的流场板;制备膜电极(membrane electrode assembly,MEA);通过改进μ-DMFC的封装结构,采用聚二甲基硅氧烷(polydimethylsiloxane,PDMS)和金属夹具对μ-DMFC进行封装,有效地避免甲醇的渗漏;并且通过测试μ-DMFC的I-V特性,比较了不同封装结构下,μ-DMFC的电性能.实验结果表明,封装结构改进后的μ-DMFC,最大电流密度为14.82 mA/cm2,最大输出功率为0.661 mW.

  5. Methanol Oxidation on Model Elemental and Bimetallic Transition Metal Surfaces

    DEFF Research Database (Denmark)

    Tritsaris, G. A.; Rossmeisl, J.

    2012-01-01

    Direct methanol fuel cells are a key enabling technology for clean energy conversion. Using density functional theory calculations, we study the methanol oxidation reaction on model electrodes. We discuss trends in reactivity for a set of monometallic and bimetallic transition metal surfaces, flat...... sites on the surface and to screen for novel bimetallic surfaces of enhanced activity. We suggest platinum copper surfaces as promising anode catalysts for direct methanol fuel cells....

  6. Dietary methanol and autism.

    Science.gov (United States)

    Walton, Ralph G; Monte, Woodrow C

    2015-10-01

    The authors sought to establish whether maternal dietary methanol during pregnancy was a factor in the etiology of autism spectrum disorders. A seven item questionnaire was given to women who had given birth to at least one child after 1984. The subjects were solicited from a large primary care practice and several internet sites and separated into two groups - mothers who had given birth to a child with autism and those who had not. Average weekly methanol consumption was calculated based on questionnaire responses. 550 questionnaires were completed by women who gave birth to a non-autistic child. On average these women consumed 66.71mg. of methanol weekly. 161 questionnaires were completed by women who had given birth to an autistic child. The average estimated weekly methanol consumption for this group was 142.31mg. Based on the results of the Wilcoxon rank sum-test, we see a significant difference between the reported methanol consumption rates of the two groups. This study suggests that women who have given birth to an autistic child are likely to have had higher intake of dietary sources of methanol than women who have not. Further investigation of a possible link of dietary methanol to autism is clearly warranted.

  7. Long-term performance and fouling analysis of full-scale direct nanofiltration (NF) installations treating anoxic groundwater

    KAUST Repository

    Beyer, Florian

    2014-10-01

    Long-term performance and fouling behavior of four full-scale nanofiltration (NF) plants, treating anoxic groundwater at 80% recovery for drinking water production, were characterized and compared with oxic NF and reverse osmosis systems. Plant operating times varied between 6 and 10 years and pretreatment was limited to 10μm pore size cartridge filtration and antiscalant dosage (2-2.5mgL-1) only. Membrane performance parameters normalized pressure drop (NPD), normalized specific water permeability (Kw) and salt retention generally were found stable over extended periods of operation (>6 months). Standard acid-base cleanings (once per year or less) were found to be sufficient to maintain satisfying operation during direct NF of the described iron rich (≤8.4mgL-1) anoxic groundwaters. Extensive autopsies of eight NF membrane elements, which had been in service since the plant startup (6-10 years), were performed to characterize and quantify the material accumulated in the membrane elements. Investigations using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), total organic carbon (TOC) and adenosine triphosphate (ATP) measurements revealed a complex mixture of organic, biological and inorganic materials. The fouling layers that developed during half to one year of operation without chemical cleaning were very thin (<2. μm). Most bio(organic) accumulates were found in the lead elements of the installations while inorganic precipitates/deposits (aluminosilicates and iron(II)sulfides) were found in all autopsied membrane elements. The high solubility of reduced metal ions and the very slow biofilm development under anoxic conditions prevented rapid fouling during direct NF of the studied groundwaters. When compared to oxic NF and RO systems in general (e.g. aerated ground waters or surface waters), the operation and performance of the described anoxic installations (with minimal pretreatment) can be described as very stable. © 2014

  8. 钯/多壁碳纳米管作为直接甲醇燃料电池阳极材料%Pd/Multi-walled Carbon Nano-tube Composite Used as Anode Materials for Direct Methanol Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    徐洋洋; 董颖男; 徐明丽; 杨喜昆

    2011-01-01

    The functionalized multi-walled carbon nano-tubes (MWCNTs) were prepared on Pd nano-particles. The eletrocatalyst was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD). The catalytic activity for methanol oxidation in alkaline media was studied by cyclic voltammograms (CVs) and chronoamperometry. The results show that Pt nano-particles highly disperse on the MWCNTs surface. The Pd/MWCNTs catalyst exhibites high catalytic activity and stability. The Pd/MWCNTs catalyst has a promising application in alkaline direct methanol fuel cells (DMFC).%将Pd纳米颗粒负载在功能化的多壁碳纳米管(MWCNTs)上制备出Pd/MWCNTs催化剂.应用TEM、XRD对其进行表征,并利用循环伏安(CVs)、时间电流法检测其对碱性溶液中甲醇的催化活性.结果表明,Pd纳米颗粒高分散在功能化的多壁碳纳米管上,在碱性溶液中Pd/MWCNTs催化剂对甲醇显出了高的催化活性和稳定性.

  9. Multi-functional reactively-sputtered copper oxide electrodes for supercapacitor and electro-catalyst in direct methanol fuel cell applications

    Science.gov (United States)

    Pawar, Sambhaji M.; Kim, Jongmin; Inamdar, Akbar I.; Woo, Hyeonseok; Jo, Yongcheol; Pawar, Bharati S.; Cho, Sangeun; Kim, Hyungsang; Im, Hyunsik

    2016-02-01

    This work reports on the concurrent electrochemical energy storage and conversion characteristics of granular copper oxide electrode films prepared using reactive radio-frequency magnetron sputtering at room temperature under different oxygen environments. The obtained films are characterized in terms of their structural, morphological, and compositional properties. X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscope studies reveal that granular, single-phase Cu2O and CuO can be obtained by controlling the oxygen flow rate. The electrochemical energy storage properties of the films are investigated by carrying out cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy tests. The electrochemical analysis reveals that the Cu2O and CuO electrodes have high specific capacitances of 215 and 272 F/g in 6 M KOH solution with a capacity retention of about 80% and 85% after 3000 cycles, respectively. Cyclic voltammetry and chronoamperometry are used to study the electrochemical energy conversion properties of the films via methanol electro-oxidation. The results show that the Cu2O and CuO electrodes are electro-catalytically active and highly stable.

  10. Structure of Pt/C and PtRu/C catalytic layers prepared by plasma sputtering and electric performance in direct methanol fuel cells (DMFC)

    Energy Technology Data Exchange (ETDEWEB)

    Caillard, A.; Brault, P.; Mathias, J. [Groupe de Recherche sur l' Energetique des Milieux Ionises, UMR6606 Universite d' Orleans, CNRS, Polytech' Orleans BP6744, F-45067 Orleans Cedex 2 (France); Coutanceau, C.; Leger, J.-M. [Laboratoire de Catalyse en Chimie Organique, UMR6503 Universite de Poitiers, CNRS, F-86022 Poitiers (France)

    2006-11-08

    Plasma sputtering process was used to deposit Pt and PtRu on conductive carbon diffusion layer. Low metal loading catalysts for methanol electrooxidation were prepared and characterized by TEM and XRD. The main result is that codeposition of Pt and Ru leads to alloy phase, whereas multi-layers deposition leads to no-alloyed structure. The electrochemical performance of sputtered Pt/C electrodes was compared with that of standard electrodes, and was found lower. However, the specific activity was much higher, indicating that the catalyst utilization efficiency was higher than that obtained with a standard electrode. Then, different bimetallic PtRu/C electrodes were prepared by plasma sputtering, leading to different catalyst structures (Pt and Ru multilayer deposition or simultaneous deposition of Pt and Ru) and composition (from 100:0 to 50:50 Pt/Ru atomic ratios). At last, the different PtRu electrodes were compared in term of DMFC electrical performance. The best efficiency of the DMFC was reached when both metals Pt and Ru are simultaneously deposited (alloyed) with a ruthenium atomic ratio of 30% or 40 % Ru depending of the working potentials of the cell. (author)

  11. Novel sulfonated poly (ether ether ketone)/phosphonic acid-functionalized titania nanohybrid membrane by an in situ method for direct methanol fuel cells

    Science.gov (United States)

    Wu, Hong; Cao, Ying; Li, Zhen; He, Guangwei; Jiang, Zhongyi

    2015-01-01

    Sulfonated poly (ether ether ketone)/phosphonic acid-functionalized titania nanohybrid membranes are prepared by an in situ method using titanium tetrachloride (TiCl4) as inorganic precursor and amino trimethylene phosphonic acid (ATMP) as modifier. Phosphonic acid-functionalized titania nanoparticles with a uniform particle size of ∼50 nm are formed and dispersed homogeneously in the SPEEK matrix with good interfacial compatibility. Accordingly, the nanohybrid membranes display remarkably enhanced proton conduction property due to the incorporation of additional sites for proton transport and the formation of well-connected channels by bridging the hydrophilic domains in SPEEK matrix. The nanohybrid membrane with 6 wt. % of phosphonic acid-functionalized titania nanoparticles exhibits the highest proton conductivity of 0.334 S cm-1 at 65 °C and 100% RH, which is 63.7% higher than that of pristine SPEEK membrane. Furthermore, the as-prepared nanohybrid membranes also show elevated thermal and mechanical stabilities as well as decreased methanol permeability.

  12. Kinetics of methanol steam reforming over COPZr-2 catalyst

    Institute of Scientific and Technical Information of China (English)

    Yongfeng Li; Weiming Lin; Lin Yu; Zhifeng Hao; Rongjian Mai

    2008-01-01

    The COPZr-2 catalyst, which was prepared in our prophase research, showed good catalytic performance in methanol steam reforming reaction. In this article, the best one was chosen as an example to study the reaction kinetics of methanol steam reforming over this type of catalyst. First, the effects of methanol conversion to outlet CO2 and methanol conversion to outlet CO on methanol pseudo contact time W/FMeOH were investigated. Then by applying the reaction route that methanol direct reforming (DR) and methanol decomposition (DE) were carried out in parallel, the reaction kinetic model with power function type was established. And the parameters for the model were estimated using a non-linear regression program which computed weighted least squares of the defined objects function. Finally, the kinetic model passed the correlation test and the F-test.

  13. Methanol Cannon Demonstrations Revisited.

    Science.gov (United States)

    Dolson, David A.; And Others

    1995-01-01

    Describes two variations on the traditional methanol cannon demonstration. The first variation is a chain reaction using real metal chains. The second example involves using easily available components to produce sequential explosions that can be musical in nature. (AIM)

  14. Transesterification of waste vegetable oil under pulse sonication using ethanol, methanol and ethanol-methanol mixtures.

    Science.gov (United States)

    Martinez-Guerra, Edith; Gude, Veera Gnaneswar

    2014-12-01

    This study reports on the effects of direct pulse sonication and the type of alcohol (methanol and ethanol) on the transesterification reaction of waste vegetable oil without any external heating or mechanical mixing. Biodiesel yields and optimum process conditions for the transesterification reaction involving ethanol, methanol, and ethanol-methanol mixtures were evaluated. The effects of ultrasonic power densities (by varying sample volumes), power output rates (in W), and ultrasonic intensities (by varying the reactor size) were studied for transesterification reaction with ethanol, methanol and ethanol-methanol (50%-50%) mixtures. The optimum process conditions for ethanol or methanol based transesterification reaction of waste vegetable oil were determined as: 9:1 alcohol to oil ratio, 1% wt. catalyst amount, 1-2 min reaction time at a power output rate between 75 and 150 W. It was shown that the transesterification reactions using ethanol-methanol mixtures resulted in biodiesel yields as high as >99% at lower power density and ultrasound intensity when compared to ethanol or methanol based transesterification reactions.

  15. A solid-polymer-electrolyte direct methanol fuel cell (DMFC) with Pt-Ru nanoparticles supported onto poly(3,4-ethylenedioxythiophene) and polystyrene sulphonic acid polymer composite as anode

    Indian Academy of Sciences (India)

    K K Tintula; S Pitchumani; P Sridhar; A K Shukla

    2010-05-01

    Nano-sized Pt-Ru supported onto a mixed-conducting polymer composite comprising poly(3,4-ethylenedioxythiophene)-polystyrene sulphonic acid (PEDOT-PSSA) is employed as anode in a solid-polymer-electrolyte direct methanol fuel cell (SPE-DMFC) and its performance compared with the SPE-DMFC employing conventional Vulcan XC-72R carbon supported Pt-Ru anode. Physical characterization of the catalyst is conducted by Fourier-transform infra-red (FTIR) spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Energy dispersive X-ray analysis (EDAX) in conjunction with cyclic voltammetry and chronoamperometry. The study suggests that PEDOT-PSSA to be a promising alternative catalyst-support-material for SPE-DMFCs.

  16. Effect of Ni Core Structure on the Electrocatalytic Activity of Pt-Ni/C in Methanol Oxidation

    Directory of Open Access Journals (Sweden)

    Vladimir Linkov

    2013-07-01

    Full Text Available Methanol oxidation catalysts comprising an outer Pt-shell with an inner Ni-core supported on carbon, (Pt-Ni/C, were prepared with either crystalline or amorphous Ni core structures. Structural comparisons of the two forms of catalyst were made using transmission electron microscopy (TEM, X-ray diffraction (XRD and X-ray photoelectron spectroscopy (XPS, and methanol oxidation activity compared using CV and chronoamperometry (CA. While both the amorphous Ni core and crystalline Ni core structures were covered by similar Pt shell thickness and structure, the Pt-Ni(amorphous/C catalyst had higher methanol oxidation activity. The amorphous Ni core thus offers improved Pt usage efficiency in direct methanol fuel cells.

  17. Matching and optimization of working condition of liquid feed direct methanol fuel cell%液体进料直接甲醇燃料电池工况的匹配及优化

    Institute of Scientific and Technical Information of China (English)

    刘桂成; 张浩; 王一拓; 王新东

    2012-01-01

    The effects on the performance of direct methanol fuel cell(DMFC)with oxygen humidifying, oxygen preheating at the cathode and placement ways of the cell were studied. Electrochemical impedance spectroscopy (EIS) test results revealed that oxygen humidifying led to a 10.3% reduction of internal resistance and improvement of the cell performance at low temperature,but oxygen humidifying resulted in flooding in the cathode and decreased the cell performance at high temperature. Oxygen preheating could ensure temperature balance in the cathode and avoid the condensation of H2O steam produced from cathode into water,improving the mass transfer ability and then enhanced the power density of cell from 46.70 Mw/cm2 to 52.48 Mw/cm2 at 55 t, which was especially notable at higher running temperature. Four feeding patterns were designed, the vertical feeding way promoted CO2 being emitted,reduced methanol crossover and obtained the maximum performance(54.13 Mw/cm2)at lower rate of methanol.%研究阴极氧气加湿、预热及电池放置方式对直接甲醇燃料电池(DMFC)性能的影响.电化学阻抗谱(EIS)测试结果显示:氧气加湿使电池内阻降低10.3%,改善了低温运行时的电池性能;在较高温度下,氧气加湿导致阴极出现水淹,降低了电池性能;氧气预热在保证阴极温度平衡的同时,避免了产物水分遇冷凝结,改善了阴极的传质性能,电池的功率密度在55℃时从46.70 mW/cm2提高到52.48 mW/cm2;运行温度越高,氧气预热对性能的改善越显著.设计了4种进料方式,其中垂直进料方式使CO2最易排出、甲醇渗透最少,甲醇流速较低时可得到最高的功率密度(54.13 mW/cm2).

  18. Preparation and Performance of Co-N-C Electro-Catalysts for Direct Methanol Fuel Cell%直接甲醇燃料电池用Co-N-C电催化剂的制备及性能

    Institute of Scientific and Technical Information of China (English)

    杨伟; 陈胜洲; 董新法; 林维明

    2012-01-01

    以三聚氰胺甲醛树脂和硝酸钴为前驱体,在Ar保护下采用高温碳化方法制备用于直接甲醇燃料电池( DMFC)阴极的含氮碳载钴(Co-N-C)氧还原电催化剂.利用热重与红外光谱联用、X射线衍射分析、元素分析等方法表征了催化剂的制备过程和结构,采用旋转圆盘电极测试考察了不同碳化温度对Co-N-C电催化剂氧还原催化活性的影响及电催化剂的耐醇性能,并采用该催化剂为阴极催化剂进行DMFC单电池测试.结果表明:Co-N-C电催化剂具有较高的电催化活性和较好的耐醇性能;其氧还原起始电位在0.5 V(vs.SCE)左右;700℃碳化温度下制备的Co-N-C电催化剂具有最高的氧还原催化活性.%Co-N-C oxygen reduction electro-catalysts for the cathode of the direct methanol fuel cell (DMFC) were first prepared via the pyrolysis in Ar atmosphere, with melamine formaldehyde resin and cobalt nitrate as the precursors. Then, the preparation and structure of the electro-catalysts were investigated by means of TG-FTIR, XRD and element analysis, and the electro-catalytic activity for oxygen reduction reaction as well as the methanol tolerance of the electro-catalysts was detected by using a rotating disk electrode. Finally, a DMFC single-cell test was carried out by using the prepared electro-catalysts as the cathode catalysts. The results indicate that Co-N-C electro-catalysts are of high electro-catalytic activity and strong methanol tolerance, and that the onset potential of the electro-catalysts for oxygen reduction is about 0.5 V (vs. SCE). Moreover, it is found that the catalyst prepared at 7001 possesses the highest electro-catalytic activity for oxygen reduction reaction.

  19. Synthèse directe du 1,1-diméthoxyméthane à partir de méthanol moyennant une modification mineure du procédé de production de formaldéhyde sur catalyseurs FeMo Direct Synthesis of 1,1-dimethoxymethane from Methanol by Minor Modification of the Formaldehyde Production Process over FeMo Catalysts

    Directory of Open Access Journals (Sweden)

    Gornay J.

    2010-09-01

    Full Text Available La réaction d’oxydation ménagée du méthanol sur catalyseurs purement redox conduit principalement à la formation de formaldéhyde. Sur des catalyseurs FeMo optimisés, des sous-produits très minoritaires tels que l’acide formique et les oxydes de carbone (COx sont également détectés. Dans le cas de catalyseurs possédant en outre des propriétés acides, des réactions de condensation/déshydratation viennent s’ajouter au schéma réactionnel d’oxydations consécutives, ce qui génère des produits supplémentaires tels que le 1,1-diméthoxyméthane (DMM, aussi appelé méthylal, le diméthyléther ou encore le formiate de méthyle. Parmi ces produits, le DMM possède un intérêt industriel particulier. En effet, de par ses propriétés physiques (très bon solvant, basse viscosité, faible tension superficielle, etc., ses débouchés englobent de nombreuses applications comme solvant vert, intermédiaire de synthèse, voire carburant, en remplacement des produits issus de la pétrochimie. La méthode de synthèse conventionnelle du DMM fait appel à 2 étapes : – production du formaldéhyde et, – réaction par catalyse acide entre le formaldéhyde et le méthanol pour finalement former le DMM. Cependant, afin de réduire les coûts de production du DMM, la mise au point d’un catalyseur et d’un procédé idoine permettant sa synthèse directe sont nécessaires. Comme susmentionné, sur un catalyseur de type FeMo, l’oxydation du méthanol conduit à la formation très majoritaire de formaldéhyde. Ce procédé utilise une faible pression partielle de méthanol, la zone de composition riche en méthanol – hors diagramme d’explosivité – n’étant pas exploitée. En nous plaçant justement dans cette zone riche en méthanol, nous avons observé, sur ce même catalyseur FeMo, la meilleure productivité en DMM jamais reportée dans la littérature (4.6 kgDMM.h−1.kgCat−1 à 553 K avec une conversion de m

  20. 直接甲醇燃料电池关键材料的表面改性及其研究进展%Research Progress and Surface Modification in Key Materials of Direct Methanol Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    何璧; 刘其阳; 李欢; 唐彬彬; 聂明; 李庆; 刘晓卫; 杜胜娟; 周倩; 廖羽佳; 王宏煜; 袁宇

    2014-01-01

    直接甲醇燃料电池( DMFC)由于结构简单、能量密度大、无污染等优点,已经成为近年来国内外研究的热点之一。简要介绍了直接甲醇燃料电池的原理,重点概述了阳极催化剂和电解质膜这两个决定电池性能的关键材料的表面改性及其研究进展。介绍了提高直接甲醇燃料电池阳极催化剂催化活性的各种改性技术,如通过离子溅射法、分子束法等传统物理方法对电极表面进行修饰,在电极材料中掺杂对甲醇催化活性较好的纳米材料等。此外,还介绍了基于降低甲醇渗透率的Nafion膜改进技术,如通过等离子蚀刻法等物理手段对膜表面进行改性,掺杂阻醇性能较好的无机化合物等。并介绍了几种具有应用前景的新型替代膜,如接枝膜、共混膜等。最后对直接甲醇燃料电池的发展应用进行了展望。%Objective Direct methanol fuel cells ( DMFC) have become the domestic and international research focus in recent years due to its many advantages, such as simple structure, high energy density and pollutionlessness. This paper reviewed the principle of DMFC and the study process of anode catalyst and proton exchange membrane was emphatically elaborated. The details in modification of the anode catalyst for improving its catalytic activity were introduced, for example, the modification of the elec-trode surface by physical methods such as ion sputtering and molecular beam method, and modification of the electrode material by doping with nanomaterials of higher methanol catalysis activity. Emphasis was laid on the studies on both Nafion membranes and the substitutes to remarkably reduce the methanol permeability, such as the modification over the membrane surface by physical means of plasma etching, and by doping with some methanol-resistant inorganic compounds. Several promising alternative membranes were introduced, such as the grafted membranes and blended

  1. Photocatalytic conversion of methane to methanol

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, C.E.; Noceti, R.P.; D`Este, J.R. [Pittsburgh Energy Technology Center, PA (United States)

    1995-12-31

    A long-term goal of our research group is the exploration of novel pathways for the direct oxidation of methane to liquid fuels, chemicals, and intermediates. The use of three relatively abundant and inexpensive reactants, light, water, and methane, to produce methanol is attractive. The products of reaction, methanol and hydrogen, are both commercially desirable, methanol being used as is or converted to a variety of other chemicals, and the hydrogen could be utilized in petroleum and/or chemical manufacturing. Methane is produced as a by-product of coal gasification. Depending upon reactor design and operating conditions, up to 18% of total gasifier product may be methane. In addition, there are vast proven reserves of geologic methane in the world. Unfortunately, a large fraction of these reserves are in regions where there is little local demand for methane and it is not economically feasible to transport it to a market. There is a global research effort under way in academia, industry, and government to find methods to convert methane to useful, more readily transportable and storable materials. Methanol, the initial product of methane oxidation, is a desirable product of conversion because it retains much of the original energy of the methane while satisfying transportation and storage requirements. Investigation of direct conversion of methane to transportation fuels has been an ongoing effort at PETC for over 10 years. One of the current areas of research is the conversion of methane to methanol, under mild conditions, using light, water, and a semiconductor photocatalyst. The use of three relatively abundant and inexpensive reactants, light, water, and methane, to produce methanol, is attractive. Research in the laboratory is directed toward applying the techniques developed for the photocatalytic splitting of the water and the photochemical conversion of methane.

  2. Long-term performance and fouling analysis of full-scale direct nanofiltration (NF) installations treating anoxic groundwater

    NARCIS (Netherlands)

    Beyer, F.; Rietman, B.M.; Zwijnenburg, A.; Brink, van den P.; Vrouwenvelder, J.S.; Jarzembowska, M.; Laurinonyte, J.; Stams, A.J.M.; Plugge, C.M.

    2014-01-01

    Long-term performance and fouling behavior of four full-scale nanofiltration (NF) plants, treating anoxic groundwater at 80% recovery for drinking water production, were characterized and compared with oxic NF and reverse osmosis systems. Plant operating times varied between 6 and 10 years and pretr

  3. A Single Visit Direct Technique to Provisionally Restore Occlusion for a Full-Mouth Rehabilitation: A Clinical Report.

    Science.gov (United States)

    El-Kerdani, Tarek; Nimmo, Arthur

    2016-01-01

    Attrition of the dentition can negatively affect esthetics and function. When reconstructing patients with attrition who require restoration at increased occlusal vertical dimension (OVD), it is necessary to first evaluate the OVD using a removable interim prosthesis to ensure that the patient will tolerate the new position. The transition to fixed interim prostheses has to be carefully planned to achieve the desired OVD. One approach is to prepare all teeth in a single day and place full-arch interim prostheses; however, this can be tiring for the patient and prosthodontist. An alternative approach is to prepare one arch and place interim prostheses, while using composite resin in the opposing arch to maintain the newly established OVD. A diagnostic wax-up at the proposed OVD is completed and duplicated in stone. A vacuform matrix is loaded with composite resin and applied to the unprepared etched teeth of the opposing arch to restore form and occlusion until full contour interim prostheses are placed at a later visit.

  4. Two 3D structured Co-Ni bimetallic oxides as cathode catalysts for high-performance alkaline direct methanol fuel cells

    Science.gov (United States)

    Liu, Yan; Shu, Chengyong; Fang, Yuan; Chen, Yuanzhen; Liu, Yongning

    2017-09-01

    Two NiCo2O4 bimetallic oxides were synthesized via a facile hydrothermal method. SEM and TEM observations show that these materials have three-dimensional (3D) dandelion-like (DL) and flower-like (FL) morphologies. Their large specific surface areas (90.68 and 19.8 m2·g-1) and porous structures provide many active sites and effective transport pathways for the oxygen reduction reaction (ORR). Electrochemical measurements with a rotating ring-disc electrode (RRDE) indicate that the electron transfer numbers of the NiCo2O4-DL and NiCo2O4-FL catalysts for ORR in an alkaline solution are 3.97 and 3.91, respectively. Fuel cells were assembled with the bimetallic oxides, PtRu/C and a polymer fiber membrane (PFM) as cathode catalysts, anode catalyst and electrolyte film, respectively. For NiCo2O4-DL, the peak power density reaches up to 73.5 mW·cm-2 at 26 °C, which is the highest room-temperature value reported to date. The high catalytic activity of NiCo2O4 is mainly attributed to the presence of many Co3+ cations that directly donate electrons to O2 to reduce it via a more efficient and effective route. Furthermore, the catalytic performance of NiCo2O4-DL is superior to that of NiCo2O4-FL because it has a higher specific surface area and is less crystalline.

  5. The Revised Version of Class I Methanol Maser Catalog

    CERN Document Server

    Val'tts, I E; Bayandina, O S

    2010-01-01

    The revised version of the class I methanol maser catalog is presented. It contains 182 sources - new class I methanol masers detected in the direction of EGOs were added to the previous number (~160 sources have been published in the first version of this catalog - see reference in the text). Electronic version has been generated in the form of html file - http://www.asc.rssi.ru/MMI. A statistical analysis was carried out within 2' around a maser position to find an identification of class I methanol masers with any objects typical for star-forming regions - UCHII regions, IRAS sources, bipolar outflows, CS lines as of dense gas tracer, masers (class II methanol masers, OH and H2O) and EGO. None of the bipolar outflow, already registered in the direction of class I methanol maser, did not coincide with EGO. The result is submitted in a form of a diagram.

  6. Direct Torque Control with Full Order Stator Flux Observer for Dual-Three Phase Induction Motor Drives

    Science.gov (United States)

    Farina, Francesco; Bojoi, Radu; Tenconi, Alberto; Profumo, Francesco

    A Direct Torque Control (DTC) strategy for dual-three phase induction motor drives is discussed in this paper. The induction machine has two sets of stator three-phase windings spatially shifted by 30 electrical degrees with isolated neutral points. The proposed control strategy is based on Proportional Integral (PI) regulators implemented in the stator flux synchronous reference frame. To improve the flux estimation, an Adaptive Stator Flux Observer (ASFO) has been used. Doing so, besides a better flux estimation in contrast to open-loop flux estimators, it is possible to use the observed currents to compensate the inverter non-linear behavior (such as dead-time effects), improving the drive performance at low speed. This is particularly important for low voltage/high current applications, as the drive considered in this paper. The advantages of the discussed control strategy are: constant inverter switching frequency, good transient and steady-state performance and less distorted machine currents in contrast to DTC schemes with variable switching frequency. Experimental results are presented for a 10kW dual three-phase induction motor drive prototype.

  7. Direct spectroscopic observation of singlet oxygen quenching and kinetic studies of physical and chemical singlet oxygen quenching rate constants of synthetic antioxidants (BHA, BHT, and TBHQ) in methanol.

    Science.gov (United States)

    Lee, Jun Hyun; Jung, Mun Yhung

    2010-08-01

    Singlet oxygen quenching by synthetic antioxidants (BHA, BHT, and TBHQ) was directly observed by spectroscopic monitoring of luminescence at 1268 nm. The luminescence data showed unambiguous evidence of singlet oxygen quenching by synthetic phenolic antioxidants with the highest activity for TBHQ, followed by BHA and BHT. The protective activities of these synthetic antioxidants on alpha-terpinene oxidation with chemically-induced singlet oxygen under dark further confirmed their singlet oxygen quenching abilities. Total singlet oxygen quenching rate constants (k(r) + k(q)) of BHA, BHT, and TBHQ were determined in a system containing alpha-terpinene (as a singlet oxygen trap) and methylene blue (as a sensitizer) during light irradiation, and the values were 5.14 x 10(7), 3.41 x 10(6), and 1.99 x 10(8) M(-1)s(-1), respectively. After the k(r) value of alpha-terpinene was first determined, the k(r) values of the synthetic antioxidants were calculated by measuring their relative reaction rates with singlet oxygen to that of alpha-terpinene under the identical conditions. The k(r) values of the BHA, BHT, and TBHQ were 3.90 x 10(5), 1.23 x 10(5), and 2.93 x 10(6), M(-1)s(-1). The percent partition of chemical quenching over total singlet oxygen quenching (k(r) x 100)/(k(r) + k(q)) for BHA, BHT, and TBHQ were 0.76%, 3.61%, and 1.47%, respectively. The results showed that the synthetic antioxidants quench singlet oxygen almost exclusively through the mechanism of physical quenching. This represents the first report on the singlet oxygen quenching mechanism of these synthetic antioxidants. Practical Application: The synthetic antioxidants, especially TBHQ, have been found to have a strong singlet oxygen quenching ability. This article also clearly showed that singlet oxygen quenching by synthetic antioxidants was mainly by the physical quenching mechanism. The results suggested that these synthetic antioxidants, especially TBHQ, could be used practically for the protection

  8. High-level direct-dynamics variational transition state theory calculations including multidimensional tunneling of the thermal rate constants, branching ratios, and kinetic isotope effects of the hydrogen abstraction reactions from methanol by atomic hydrogen.

    Science.gov (United States)

    Meana-Pañeda, Rubén; Truhlar, Donald G; Fernández-Ramos, Antonio

    2011-03-07

    We report a detailed theoretical study of the hydrogen abstraction reaction from methanol by atomic hydrogen. The study includes the analysis of thermal rate constants, branching ratios, and kinetic isotope effects. Specifically, we have performed high-level computations at the MC3BB level together with direct dynamics calculations by canonical variational transition state theory (CVT) with the microcanonically optimized multidimensional tunneling (μOMT) transmission coefficient (CVT/μOMT) to study both the CH(3)OH+H→CH(2)OH+H(2) (R1) reaction and the CH(3)OH+H→CH(3)O+H(2) (R2) reaction. The CVT/μOMT calculations show that reaction R1 dominates in the whole range 298≤T (K)≤2500 and that anharmonic effects on the torsional mode about the C-O bond are important, mainly at high temperatures. The activation energy for the total reaction sum of R1 and R2 reactions changes substantially with temperature and, therefore, the use of straight-line Arrhenius plots is not valid. We recommend the use of new expressions for the total R1 + R2 reaction and for the R1 and R2 individual reactions.

  9. Research of CO2 mass transfer in direct methanol fuel cell%直接甲醇燃料电池中CO2传质的研究

    Institute of Scientific and Technical Information of China (English)

    胡青青; 倪红军; 李志扬; 汪兴兴

    2011-01-01

    In order to promote the effective mass transfer of CO2 in direct methanol fuel cell (DMFC) and improve the performance of DMFC, in this paper, the application prospects and the present problems of DMFC were summarized, the operation principle was simply introduced, the mass transfer mecharism of CO2 in the DMFC electrolyte was analyzed and the impact factors were illustrated. The previous study on the status of CO2 mass transfer was introduced, and a ne vision for CO2 mass transfer was brought forward.%为了促进直接甲醇燃科电池(DMFC)中CO2的有效传质,从而提高其性能,综述了DMFC的应用前景及面临的问题,简单介绍了DMFC工作的原理,分析了DMFC中CO2的传质机理并进一步阐述了其影响因素,介绍了前人对CO2传质研究的现状,并在此基础上提出了研究CO2的新设想.

  10. Effect of the full implementation of the European Working Time Directive on operative training in adult cardiac surgery.

    Science.gov (United States)

    Mahesh, Balakrishnan; Sharples, Linda; Codispoti, Massimiliano

    2014-01-01

    Surgical specialties rely on practice and apprenticeship to acquire technical skills. In 2009, the final reduction in working hours to 48 per week, in accordance with the European Working Time Directive (EWTD), has also led to an expansion in the number of trainees. We examined the effect of these changes on operative training in a single high-volume [>1500 procedures/year] adult cardiac surgical center. Setting: A single high-volume [>1500 procedures/year] adult cardiac surgical center. Design: Consecutive data were prospectively collected into a database and retrospectively analyzed. Procedures and Main Outcome Measures: Between January 2006 and August 2010, 6688 consecutive adult cardiac surgical procedures were analyzed. The proportion of cases offered for surgical training were compared for 2 non-overlapping consecutive time periods: 4504 procedures were performed before the final implementation of the EWTD (Phase 1: January 2006-December 2008) and 2184 procedures after the final implementation of the EWTD (Phase 2: January 2009-August 2010). Other predictors of training considered in the analysis were grade of trainee, logistic European system for cardiac operative risk evaluation (EuroSCORE), type of surgical procedure, weekend or late procedure, and consultant. Logistic regression analysis was used to determine the predictors of training cases (procedure performed by trainee) and to evaluate the effect of the EWTD on operative surgical training after correcting for confounding factors. Proportion of training cases rose from 34.6% (1558/4504) during Phase 1 to 43.6% (953/2184) in Phase 2 (p surgery other than coronary artery bypass grafts. Implementation of the final phase of EWTD has not decreased training in a high-volume center. The positive adjustment of trainers' attitudes and efforts to match trainees' needs allow maintenance of adequate training, despite reduction in working hours and increasing patients' risk profile. Copyright © 2014 Association of

  11. Methanol may function as a cross-kingdom signal.

    Directory of Open Access Journals (Sweden)

    Yuri L Dorokhov

    Full Text Available Recently, we demonstrated that leaf wounding results in the synthesis of pectin methylesterase (PME, which causes the plant to release methanol into the air. Methanol emitted by a wounded plant increases the accumulation of methanol-inducible gene mRNA and enhances antibacterial resistance as well as cell-to-cell communication, which facilitates virus spreading in neighboring plants. We concluded that methanol is a signaling molecule involved in within-plant and plant-to-plant communication. Methanol is considered to be a poison in humans because of the alcohol dehydrogenase (ADH-mediated conversion of methanol into toxic formaldehyde. However, recent data showed that methanol is a natural compound in normal, healthy humans. These data call into question whether human methanol is a metabolic waste product or whether methanol has specific function in humans. Here, to reveal human methanol-responsive genes (MRGs, we used suppression subtractive hybridization cDNA libraries of HeLa cells lacking ADH and exposed to methanol. This design allowed us to exclude genes involved in formaldehyde and formic acid detoxification from our analysis. We identified MRGs and revealed a correlation between increases in methanol content in the plasma and changes in human leukocyte MRG mRNA levels after fresh salad consumption by volunteers. Subsequently, we showed that the methanol generated by the pectin/PME complex in the gastrointestinal tract of mice induces the up- and downregulation of brain MRG mRNA. We used an adapted Y-maze to measure the locomotor behavior of the mice while breathing wounded plant vapors in two-choice assays. We showed that mice prefer the odor of methanol to other plant volatiles and that methanol changed MRG mRNA accumulation in the mouse brain.We hypothesize that the methanol emitted by wounded plants may have a role in plant-animal signaling. The known positive effect of plant food intake on human health suggests a role for

  12. Abacavir methanol 2.5-solvate

    Directory of Open Access Journals (Sweden)

    Phuong-Truc T. Pham

    2009-08-01

    Full Text Available The structure of abacavir (systematic name: {(1S,4R-4-[2-amino-6-(cyclopropylamino-9H-purin-9-yl]cyclopent-2-en-1-yl}methanol, C14H18N6O·2.5CH3OH, consists of hydrogen-bonded ribbons which are further held together by additional hydrogen bonds involving the hydroxyl group and two N atoms on an adjacent purine. The asymmetric unit also contains 2.5 molecules of methanol solvate which were grossly disordered and were excluded using SQUEEZE subroutine in PLATON [Spek, (2009. Acta Cryst. D65, 148–155].

  13. Methanol exchange between grassland and the atmosphere

    Directory of Open Access Journals (Sweden)

    A. Brunner

    2007-01-01

    Full Text Available Concentrations and fluxes of methanol were measured above two differently managed grassland fields (intensive and extensive in central Switzerland during summer 2004. The measurements were performed with a proton-transfer-reaction mass-spectrometer and fluxes were determined by the eddy covariance method. The observed methanol emission showed a distinct diurnal cycle and was strongly correlated with global radiation and water vapour flux. Mean and maximum daily emissions were found to depend on grassland species composition and, for the intensive field, also on the growing state. The extensive field with a more complex species composition had higher emissions than the graminoid-dominated intensive field, both on an area and on a biomass basis. A simple parameterisation depending on the water vapour flux and the leaf area index allowed a satisfying simulation of the temporal variation of methanol emissions over the growing phase. Accumulated carbon losses due to methanol emissions accounted for 0.024 and 0.048% of net primary productivity for the intensive and extensive field, respectively. The integral methanol emissions over the growing periods were more than one order of magnitude higher than the emissions related to cut and drying events.

  14. Investigation of Supported Pd-Based Electrocatalysts for the Oxygen Reduction Reaction: Performance, Durability and Methanol Tolerance

    Directory of Open Access Journals (Sweden)

    Carmelo Lo Vecchio

    2015-11-01

    Full Text Available Next generation cathode catalysts for direct methanol fuel cells (DMFCs must have high catalytic activity for the oxygen reduction reaction (ORR, a lower cost than benchmark Pt catalysts, and high stability and high tolerance to permeated methanol. In this study, palladium catalysts supported on titanium suboxides (Pd/TinO2n–1 were prepared by the sulphite complex route. The aim was to improve methanol tolerance and lower the cost associated with the noble metal while enhancing the stability through the use of titanium-based support; 30% Pd/Ketjenblack (Pd/KB and 30% Pd/Vulcan (Pd/Vul were also synthesized for comparison, using the same methodology. The catalysts were ex-situ characterized by physico-chemical analysis and investigated for the ORR to evaluate their activity, stability, and methanol tolerance properties. The Pd/KB catalyst showed the highest activity towards the ORR in perchloric acid solution. All Pd-based catalysts showed suitable tolerance to methanol poisoning, leading to higher ORR activity than a benchmark Pt/C catalyst in the presence of low methanol concentration. Among them, the Pd/TinO2n–1 catalyst showed a very promising stability compared to carbon-supported Pd samples in an accelerated degradation test of 1000 potential cycles. These results indicate good perspectives for the application of Pd/TinO2n–1 catalysts in DMFC cathodes.

  15. Transient analysis and control of bias magnetic state in the transformer of on-line pulse-width-modulation switching full bridge direct current-direct current converter

    Science.gov (United States)

    Chen, Jiaxin; Guo, Youguang; Zhu, Jianguo; Wei Lin, Zhi

    2012-04-01

    This paper presents a finite element analysis (FEA) based method for analyzing and controlling the bias magnetic state of the transformer of a pulse-width-modulation (PWM) switching full bridge dc-dc converter. A field-circuit indirect coupling method for predicting the transient bias magnetic state is introduced first. To increase flexibility of the proposed method, a novel transformer model which can address not only its basic input-output characteristic, but also the nonlinear magnetizing inductance, is proposed. Both the asymmetric characteristic and the variable laws of the current flowing through the two secondary windings during the period of PWM switching-off state are highlighted. Finally, the peak magnetizing current controlled method based on the on-line magnetizing current computation is introduced. Analysis results show that this method can address the magnetic saturation at winding ends, and hence many previous difficulties, such as the start-up process and asymmetry of power electronics, can be easily controlled.

  16. The toxicity of methanol

    Energy Technology Data Exchange (ETDEWEB)

    Tephly, T.R. (Univ. of Iowa, Iowa City (USA))

    1991-01-01

    Methanol toxicity in humans and monkeys is characterized by a latent period of many hours followed by a metabolic acidosis and ocular toxicity. This is not observed in most lower animals. The metabolic acidosis and blindness is apparently due to formic acid accumulation in humans and monkeys, a feature not seen in lower animals. The accumulation of formate is due to a deficiency in formate metabolism which is, in turn, related, in part, to low hepatic tetrahydrofolate (H{sub 4}folate). An excellent correlation between hepatic H{sub 4} folate and formate oxidation rates has been shown within and across species. Thus, humans and monkeys possess low hepatic H{sub 4}folate levels, low rates of formate oxidation and accumulation of formate after methanol. Formate, itself, produces blindness in monkeys in the absence of metabolic acidosis. In addition to low hepatic H{sub 4}folate concentrations, monkeys and humans also have low hepatic 10-formyl H{sub 4}folate dehydrogenase levels, the enzyme which is the ultimate catalyst for conversion of formate to carbon dioxide. This review presents the basis for the role of folic acid-dependent reactions in the regulation of methanol toxicity.

  17. Evidence of anomalous behavior of intermolecular interactions at low concentration of methanol in ethanol-methanol binary system.

    Science.gov (United States)

    Nilavarasi, K; Kartha, Thejus R; Madhurima, V

    2018-01-05

    At low concentrations of methanol in a binary system of ethanol and methanol, uniquely complex molecular interactions are reported here. Previous studies indicate that ethanol molecules form aggregates held together by hydrogen bonding (O-H-O) and also dispersive forces. Addition of small amount of methanol tends to break the hydrogen bond network of ethanol due to the larger polarity of methanol. This leads to the ethanol molecules becoming somewhat isolated from each other within a scaffolding network of methanol molecules, as seen from the present molecular dynamics simulations. This is an indication of a repulsive force that dominates among the two different alcohols. At higher molar concentration of methanol (Xm > 0.3817), the strength and extent (number) of formation of hydrogen bonds between ethanol and methanol increase. The geometry of molecular structure at high concentration favors the fitting of component molecules with each other. Intermolecular interactions in the ethanol-methanol binary system over the entire concentration range were investigated in detail using broadband dielectric spectroscopy, FTIR, surface tension and refractive index studies. Molecular dynamics simulations show that the hydrogen bond density is a direct function of the number of methanol molecules present, as the ethanol aggregates are not strictly hydrogen-bond constructed which is in agreement with the experimental results. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Improvement of biodiesel methanol blends

    Directory of Open Access Journals (Sweden)

    Y. Datta Bharadwaz

    2016-06-01

    Full Text Available The main objective of this work was to improve the performance of biodiesel–methanol blends in a VCR engine by using optimized engine parameters. For optimization of the engine, operational parameters such as compression ratio, fuel blend, and load are taken as factors, whereas performance parameters such as brake thermal efficiency (Bth and brake specific fuel consumption (Bsfc and emission parameters such as carbon monoxide (CO, unburnt hydrocarbons (HC, Nitric oxides (NOx and smoke are taken as responses. Experimentation is carried out as per the design of experiments of the response surface methodology. Optimization of engine operational parameters is carried out using Derringers Desirability approach. From the results obtained it is inferred that the VCR engine has maximum performance and minimum emissions at 18 compression ratio, 5% fuel blend and at 9.03 kg of load. At this optimized operating conditions of the engine the responses such as brake thermal efficiency, brake specific fuel consumption, carbon monoxide, unburnt hydrocarbons, nitric oxide, and smoke are found to be 31.95%, 0.37 kg/kW h, 0.036%, 5 ppm, 531.23 ppm and 15.35% respectively. It is finally observed from the mathematical models and experimental data that biodiesel methanol blends have maximum efficiency and minimum emissions at optimized engine parameters.

  19. Progress in portable direct methanol fuel cell

    Institute of Scientific and Technical Information of China (English)

    佘沛亮; 胡信国; 陈怀林

    2004-01-01

    The progresses in portable DMFC worldwide were reviewed, the current status of its components, catalysts, proton exchange membrane and flow field plate, the market development of portable electronic appliances, such as mobile phone, PDA and notebook were introduced.

  20. Direct Methanol Fuel Cell Battery Replacement Program

    Science.gov (United States)

    2011-04-11

    Electrochemical Society Meeting, ABS#1089, Oct. 16th 2008, Hawaii, USA. 2. Hall, T.D.; Grice, C.R.; Swenson, L.R.; Smotkin, E.S., “Reversible and irreversible...degradation modes of DMFC anode catalysts”, 212th Electrochemical Society Meeting, ABS#819, Oct. 14th 2008, Hawaii, USA. 3. Yuan Zhang, James Cooper...Paul McGinn “Combinatorial Screening of Fuel Cell Catalysts” 211th Electrochemical Society Meeting, Phoenix, AZ, May, 2008 4. Hall, T.D.; Grice, Corey

  1. 石墨烯用作直接甲醇燃料电池阳极催化剂载体%Modified graphene as anode catalyst for direct methanol fuel cell

    Institute of Scientific and Technical Information of China (English)

    朱艳霞; 韩大量; 黄成德

    2015-01-01

    直接甲醇燃料电池(DMFC)阳极催化剂是决定电池性能、寿命和成本的关键材料之一。近年来人们主要从提高催化剂活性和降低催化剂成本两个方面出发进行了大量的研究,有力地推动了直接甲醇燃料电池的发展。石墨烯作为一种载体材料能够显著提高催化剂的催化活性和稳定性,引起了人们极大的兴趣。介绍了近几年石墨烯在直接甲醇燃料电池阳极催化剂载体的进展,并对其在未来的应用进行了展望。%Anode catalyst is one of the key materials determining the performance, longevity and cost of direct methanol fuel cell(DMFC). In recent years, extensive researches effectively promoting the development of DMFC are carried out, and these researches are mainly about two aspects:the activity improvement of catalyst and lowering the cost of catalyst. Graphene as a new carbon material can significantly improve the activity and stability of the catalyst. The research progress of modified graphene as anode catalyst of DMFC in recent years was reviewed and the application in the future was prospected.

  2. Methanol - alternative fuel road traffic

    Energy Technology Data Exchange (ETDEWEB)

    Muendler, H.

    1980-09-01

    This brochure names the fuel properties that are required for road traffic, discusses the replacement of petrol by methanol, discusses the possibilities of manufacturing methanol, draws up a timetable and an organigram for a (M-15) large scale test and compares costs of petrol, methanol, synthesis process petrol and hydrogenation process petrol. Furthermore, the technical requirements of vehicles as well as test results of exhaust gas emissions are also discussed.

  3. ACUTE METHANOL INTOXICATIONS – A CHALLENGE FOR CLINICAL TOXICOLOGY

    Directory of Open Access Journals (Sweden)

    Petko Marinov

    2016-10-01

    Full Text Available Purpose: Methanol (CH3OH is a monohydric alcohol, vastly used both in housekeeping and industry. Although the acute methanol intoxications are rare, they may include life-threatening symptoms, substantial lethality and negative consequences such as neurological disorders and vision damage. Aim of the work is to conduct a retrospective study on the acute methanol intoxications within Varna region for a 10-year period (2006-2015. Material/Methods: This study covers 39 patients of the Clinic for Intensive Treatment of Acute Intoxications and Toxicoallergies at Naval Hospital – Varna, all of which had their diagnosis confirmed, including gas chromatography methods. Results: Methanol intoxication prevalence showed male/female ratio close to 2.9:1. The major part of the cases concerned economically active population, the age group of 25-60 being the most affected. In all instances an oral methanol intake has been involved. Death occurred in 14 cases (35.9%

  4. Biodiesel Production from Acidified Oils via Supercritical Methanol

    Directory of Open Access Journals (Sweden)

    Jianxin Li

    2011-12-01

    Full Text Available In biodiesel production, the vegetable oil used as raw material for transesterification should be free of water and free fatty acids (FFAs, which may consume catalyst and reduce catalyst efficiency. In this work biodiesel was prepared from acidified oils (AO through a supercritical methanol route, in which the esterification of FFAs and transesterification of glyceride with methanol occurred simultaneously. The effects of the mass ratio of methanol to AO, the operation temperature as well as the water content on the FFAs conversion and glycerol yield were investigated. The results indicated that the FFAs conversion for esterification under the condition of 1:1 methanol/oil ratio, 310 °C and 15 min reaction time reached 98.7%, and the glycerol yield for transesterification under 0.25:1 methanol/oil ratio, 290 °C and 20 min reaction time reached 63.5% respectively.

  5. Methanol and acetaldehyde fluxes over ryegrass

    Science.gov (United States)

    Custer, Thomas; Schade, Gunnar

    2007-09-01

    Oxygenated volatile organic compounds (OVOCs) play an active role in tropospheric chemistry but our knowledge concerning their release and ultimate fate is limited. However, the recent introduction of Proton Transfer Reaction Mass Spectrometry (PTRMS) has improved our capability to make direct field observations of OVOC mixing ratios and fluxes. We used PTRMS in an eddy covariance setup to measure selected OVOC exchange rates above a well-characterized agricultural plot in Northern Germany. In fall 2003, mixing ratios of methanol and acetaldehyde 2 m above the field ranged from 1 to 10 and 0.4 to 2.1 ppb, respectively, well correlated with one another. Fluxes of both gases were followed for growing Italian ryegrass (Lolium multiflorum) over a significant portion of its life cycle. Diurnally fluctuating emissions of methanol and very small acetaldehyde fluxes were observed up to the cutting and removal of the grass. Methanol emissions were exponentially related to ambient temperatures and appeared to be higher during the grass' rapid leaf area expansion and after a rain event. Acetaldehyde exchanges averaged over the whole period indicated very slow deposition. Our measurements confirm previous, similar results, as well as presumptions that grasses are comparatively low methanol emitters compared to non-grass species.

  6. A full-Newton step feasible interior-point algorithm for P∗(κ-LCP based on a new search direction

    Directory of Open Access Journals (Sweden)

    Behrouz Kheirfam

    2016-12-01

    Full Text Available In this paper, we present a full-Newton step feasible interior-point algorithm for a P∗(κ linear complementarity problem based on a new search direction. We apply a vector-valued function generated by a univariate function on nonlinear equations of the system which defines the central path. Furthermore, we derive the iteration bound for the algorithm, which coincides with the best-known iteration bound for these types of algorithms. Numerical results show that the proposed algorithm is competitive and reliable.

  7. Methanol synthesis beyond chemical equilibrium

    NARCIS (Netherlands)

    van Bennekom, J. G.; Venderbosch, R. H.; Winkelman, J. G. M.; Wilbers, E.; Assink, D.; Lemmens, K. P. J.; Heeres, H. J.

    2013-01-01

    In commercial methanol production from syngas, the conversion is thermodynamically limited to 0.3-0.7 leading to large recycles of non-converted syngas. This problem can be overcome to a significant extent by in situ condensation of methanol during its synthesis which is possible nowadays due to the

  8. Ignition delay of dual fuel engine operating with methanol ignited by pilot diesel

    Institute of Scientific and Technical Information of China (English)

    Hongbo ZOU; Lijun WANG; Shenghua LIU; Yu LI

    2008-01-01

    An investigation on the ignition delay of a dual fuel engine operating with methanol ignited by pilot diesel was conducted on a TY1100 direct-injection diesel engine equipped with an electronic controlled methanol low-pressure injection system. The experimental results show that the polytropic index of compression process of the dual fuel engine decreases linearly while the ignition delay increases with the increase in methanol mass fraction. Compared with the conventional diesel engine, the igni-tion delay increment of the dual fuel engine is about 1.5° at a methanol mass fraction of 62%, an engine speed of 1600 r/min, and full engine load. With the elevation of the intake charge temperature from 20℃ to 40℃ and then to 60℃, the ignition delay of the dual fuel engine decreases and is more obvious at high temperature. Moreover, with the increase in engine speed, the ignition delay of the dual fuel engine by time scale (ms) decreases clearly under all engine operating conditions. However, the ignition delay of the dual fuel engine increases remark-ably by advancing the delivery timing of pilot diesel, espe-cially at light engine loads.

  9. Investigations into low pressure methanol synthesis

    DEFF Research Database (Denmark)

    Sharafutdinov, Irek

    The central topic of this work has been synthesis, characterization and optimization of novel Ni-Ga based catalysts for hydrogenation of CO2 to methanol. The overall goal was to search for materials that could be used as a low temperature (and low pressure) methanol synthesis catalyst....... Among them, Ni-Ga has been chosen, primarily due to low price of constituent metals. After the preliminary optimization work, an optimal catalyst composition and preparation method has been suggested. Indeed, for an optimal catalyst, which is a SiO2 supported Ni-Ga prepared from a solution of nitrates...... due to carbon formation) and under accelerated ageing conditions (due to dealloying). However, the initial activity could always be restored after treatment in hydrogen flow at elevated temperatures. The work in the direction of suppression of deactivation and by-product formation is still in progress....

  10. Effect of P on the electrochemical activity of carbon supported Pt-Ru alloy catalyst for methanol oxidation.

    CSIR Research Space (South Africa)

    Mohlala, M

    2007-11-01

    Full Text Available In polymer electrolyte membrane fuel cell (PEMFC), platinum is recognized to be the most active metal for methanol oxidation, however there is a strong CO adsorption tendency, which blocks the surface for further methanol adsorption and leads...

  11. A novel PWM control for a bi-directional full-bridge DC-DC converter with smooth conversion mode transitions

    Science.gov (United States)

    Lorentz, V. R. H.; Schwarzmann, H.; März, M.; Bauer, A. J.; Ryssel, H.; Frey, L.; Poure, P.; Braun, F.

    2011-08-01

    A novel CMOS integrated pulse-width modulation (PWM) control circuit allowing smooth transitions between conversion modes in full-bridge based bi-directional DC-DC converters operating at high switching frequencies is presented. The novel PWM control circuit is able to drive full-bridge based DC-DC converters performing step-down (i.e. buck) and step-up (i.e. boost) voltage conversion in both directions, thus allowing charging and discharging of the batteries in mobile systems. It provides smooth transitions between buck, buck-boost and boost modes. Additionally, the novel PWM control loop circuit uses a symmetrical triangular carrier, which overcomes the necessity of using an output phasing circuit previously required in PWM controllers based on sawtooth oscillators. The novel PWM control also enables to build bi-directional DC-DC converters operating at high switching frequencies (i.e. up to 10 MHz and above). Finally, the proposed PWM control circuit also allows the use of an average lossless inductor-current sensor for sensing the average load current even at very high switching frequencies. In this article, the proposed PWM control circuit is modelled and the integrated CMOS schematic is given. The corresponding theory is analysed and presented in detail. The circuit simulations realised in the Cadence Spectre software with a commercially available 0.18 µm mixed-signal CMOS technology from UMC are shown. The PWM control circuit was implemented in a monolithic integrated bi-directional CMOS DC-DC converter ASIC prototype. The fabricated prototype was tested experimentally and has shown performances in accordance with the theory.

  12. Vertical fluxes and atmospheric cycling of methanol, acetaldehyde, and acetone in a coastal environment

    Directory of Open Access Journals (Sweden)

    M. Yang

    2013-03-01

    Full Text Available We present here vertical fluxes of methanol, acetaldehyde, and acetone measured directly with eddy covariance (EC during March to July 2012 near the southwest coast of the UK. The performance of the proton-transfer reaction mass spectrometer (PTR-MS for flux measurement is characterized, with additional considerations given to the homogeneity and stationarity assumptions required by EC. Concentrations and fluxes of these compounds vary significantly with time of day and wind direction. Higher values of acetaldehyde and acetone are usually observed in the daytime and from the direction of a forested park, most likely due to light-driven emissions from terrestrial plants. Methanol concentration and flux do not demonstrate clear diel variability, suggesting sources in addition to plants. We estimate air–sea exchange and photochemical rates of these compounds, which are compared to measured vertical fluxes. For acetaldehyde, the mean (1σ concentration of 0.13 (0.02 ppb at night may be maintained by oceanic emission, while photochemical destruction outpaces production during the day. Air-sea exchange and photochemistry are probably net sinks of methanol and acetone in this region. Their nighttime concentrations of 0.46 (0.20 and 0.39 (0.08 ppb appear to be affected more by terrestrial emissions and long distance transport, respectively.

  13. Adaptation of Hansenula polymorpha to methanol: a transcriptome analysis

    Directory of Open Access Journals (Sweden)

    Kuipers Oscar P

    2010-01-01

    Full Text Available Abstract Background Methylotrophic yeast species (e.g. Hansenula polymorpha, Pichia pastoris can grow on methanol as sole source of carbon and energy. These organisms are important cell factories for the production of recombinant proteins, but are also used in fundamental research as model organisms to study peroxisome biology. During exponential growth on glucose, cells of H. polymorpha typically contain a single, small peroxisome that is redundant for growth while on methanol multiple, enlarged peroxisomes are present. These organelles are crucial to support growth on methanol, as they contain key enzymes of methanol metabolism. In this study, changes in the transcriptional profiles during adaptation of H. polymorpha cells from glucose- to methanol-containing media were investigated using DNA-microarray analyses. Results Two hours after the shift of cells from glucose to methanol nearly 20% (1184 genes of the approximately 6000 annotated H. polymorpha genes were significantly upregulated with at least a two-fold differential expression. Highest upregulation (> 300-fold was observed for the genes encoding the transcription factor Mpp1 and formate dehydrogenase, an enzyme of the methanol dissimilation pathway. Upregulated genes also included genes encoding other enzymes of methanol metabolism as well as of peroxisomal β-oxidation. A moderate increase in transcriptional levels (up to 4-fold was observed for several PEX genes, which are involved in peroxisome biogenesis. Only PEX11 and PEX32 were higher upregulated. In addition, an increase was observed in expression of the several ATG genes, which encode proteins involved in autophagy and autophagy processes. The strongest upregulation was observed for ATG8 and ATG11. Approximately 20% (1246 genes of the genes were downregulated. These included glycolytic genes as well as genes involved in transcription and translation. Conclusion Transcriptional profiling of H. polymorpha cells shifted from

  14. Methanol Production by a Broad Phylogenetic Array of Marine Phytoplankton.

    Directory of Open Access Journals (Sweden)

    Tracy J Mincer

    Full Text Available Methanol is a major volatile organic compound on Earth and serves as an important carbon and energy substrate for abundant methylotrophic microbes. Previous geochemical surveys coupled with predictive models suggest that the marine contributions are exceedingly large, rivaling terrestrial sources. Although well studied in terrestrial ecosystems, methanol sources are poorly understood in the marine environment and warrant further investigation. To this end, we adapted a Purge and Trap Gas Chromatography/Mass Spectrometry (P&T-GC/MS method which allowed reliable measurements of methanol in seawater and marine phytoplankton cultures with a method detection limit of 120 nanomolar. All phytoplankton tested (cyanobacteria: Synechococcus spp. 8102 and 8103, Trichodesmium erythraeum, and Prochlorococcus marinus, and Eukarya (heterokont diatom: Phaeodactylum tricornutum, coccolithophore: Emiliania huxleyi, cryptophyte: Rhodomonas salina, and non-diatom heterokont: Nannochloropsis oculata produced methanol, ranging from 0.8-13.7 micromolar in culture and methanol per total cellular carbon were measured in the ranges of 0.09-0.3%. Phytoplankton culture time-course measurements displayed a punctuated production pattern with maxima near early stationary phase. Stabile isotope labeled bicarbonate incorporation experiments confirmed that methanol was produced from phytoplankton biomass. Overall, our findings suggest that phytoplankton are a major source of methanol in the upper water column of the world's oceans.

  15. Driver Steering Control and Full Vehicle Dynamics Study Based on a Nonlinear Three-Directional Coupled Heavy-Duty Vehicle Model

    Directory of Open Access Journals (Sweden)

    S. H. Li

    2014-01-01

    Full Text Available Under complicated driving situations, such as cornering brake, lane change, or barrier avoidance, the vertical, lateral, and longitudinal dynamics of a vehicle are coupled and interacted obviously. This work aims to propose the suitable vehicle and driver models for researching full vehicle dynamics in complicated conditions. A nonlinear three-directional coupled lumped parameters (TCLP model of a heavy-duty vehicle considering the nonlinearity of suspension damping and tire stiffness is built firstly. Then a modified preview driver model with nonlinear time delay is proposed and connected to the TCLP model to form a driver-vehicle closed-loop system. The presented driver-vehicle closed-loop system is evaluated during a double-lane change and compared with test data, traditional handling stability vehicle model, linear full vehicle model, and other driver models. The results show that the new driver model has better lane keeping performances than the other two driver models. In addition, the effects of driver model parameters on lane keeping performances, handling stability, ride comfort, and roll stability are discussed. The models and results of this paper are useful to enhance understanding the effects of driver behaviour on full vehicle dynamics.

  16. Evaluation of FRP Confinement Models for Substandard Rectangular RC Columns Based on Full-Scale Reversed Cyclic Lateral Loading Tests in Strong and Weak Directions

    Directory of Open Access Journals (Sweden)

    Hamid Farrokh Ghatte

    2016-09-01

    Full Text Available Although many theoretical and experimental studies are available on external confinement of columns using fiber-reinforced polymer (FRP jackets, as well as numerous models proposed for the axial stress-axial strain relation of concrete confined with FRP jackets, they have not been validated with a sufficient amount and variety of experimental data obtained through full-scale tests of reinforced concrete (RC columns with different geometrical and mechanical characteristics. Particularly, no systematical experimental data have been presented on full-scale rectangular substandard RC columns subjected to reversed cyclic lateral loads along either their strong or weak axes. In this study, firstly, test results of five full-scale rectangular substandard RC columns with a cross-sectional aspect ratio of two (300 mm × 600 mm are briefly summarized. The columns were tested under constant axial load and reversed cyclic lateral loads along their strong or weak axes before and after retrofitting with external FRP jackets. In the second stage, inelastic lateral force-displacement relationships of the columns are obtained analytically, making use of the plastic hinge assumption and different FRP confinement models available in the literature. Finally, the analytical findings are compared with the test results for both strong and weak directions of the columns. Comparisons showed that use of different models for the stress-strain relationship of FRP-confined concrete can yield significantly non-conservative or too conservative retrofit designs, particularly in terms of deformation capacity.

  17. Biological conversion of biogas to methanol using methanotrophs isolated from solid-state anaerobic digestate.

    Science.gov (United States)

    Sheets, Johnathon P; Ge, Xumeng; Li, Yueh-Fen; Yu, Zhongtang; Li, Yebo

    2016-02-01

    The aim of this work was to isolate methanotrophs (methane oxidizing bacteria) that can directly convert biogas produced at a commercial anaerobic digestion (AD) facility to methanol. A methanotrophic bacterium was isolated from solid-state anaerobic digestate. The isolate had characteristics comparable to obligate methanotrophs from the genus Methylocaldum. This newly isolated methanotroph grew on biogas or purified CH4 and successfully converted biogas from AD to methanol. Methanol production was achieved using several methanol dehydrogenase (MDH) inhibitors and formate as an electron donor. The isolate also produced methanol using phosphate with no electron donor or using formate with no MDH inhibitor. The maximum methanol concentration (0.43±0.00gL(-1)) and 48-h CH4 to methanol conversion (25.5±1.1%) were achieved using biogas as substrate and a growth medium containing 50mM phosphate and 80mM formate.

  18. Methanol/air fuel cells: catalytic aspects and experimental diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, M.F.; Sieben, J.M.; Pilla, A.S.; Duarte, M.M.E.; Mayer, C.E. [Instituto de Ingenieria Electroquimica y Corrosion, Depto. de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)

    2008-07-15

    Methanol/air fuel cell with direct feed of methanol has received growing attention due to the possibility of using a liquid fuel of simple storing. This work comments studies on the preparation of PtRu catalysts for methanol oxidation and on the influence of different operative parameter on the performance of a lab scale fuel cell. The best conditions for PtRu catalysts preparation using metal electrodeposition techniques were found. Different carbon materials were used, such as glassy carbon, carbon paper and graphite fiber cloths and felts. The more active materials were found to be graphite felts after being preoxidized electrochemically to obtain a higher surface oxide concentration. Acceptable performance of the fuel cell was obtained working at 90 C and low methanol concentration, because in these conditions the potential, the transport process rates and the electrode reaction kinetics increase. (author)

  19. Towards a methanol economy: Zeolite catalyzed production of synthetic fuels

    DEFF Research Database (Denmark)

    Mentzel, Uffe Vie

    chapter is a literature study of Mobil’s “methanol to hydrocarbons” (MTH) process, giving an overview of the history of the process, the nature of the employed catalysts, and the reaction mechanism. In the third chapter, a series of experiments concerning co conversion of ethane and methanol over......, the conversion capacities for all four alcohols are markedly lower than for H-ZSM-5, and H Beta has higher conversion capacity for methanol than the other alcohols. Furthermore, conventional and mesoporous H Ga MFI was employed in the conversion of methanol and 2 propanol. These catalysts showed a lower...... selectivity towards aromatics than H-ZSM-5 and the mesoporous H-Ga-MFI deactivated extremely slowly during the conversion of 2-propanol and only very small amounts of coke were deposited on the gallium based zeolites compared to H-ZSM-5. In the fifth chapter the direct zeolite catalyzed production...

  20. NMR and Electrochemical Investigation of the Transport Properties of Methanol and Water in Nafion and Clay-Nanocomposites Membranes for DMFCs

    Directory of Open Access Journals (Sweden)

    Vincenzo Baglio

    2012-06-01

    Full Text Available Water and methanol transport behavior, solvents adsorption and electrochemical properties of filler-free Nafion and nanocomposites based on two smectite clays, were investigated using impedance spectroscopy, DMFC tests and NMR methods, including spin-lattice relaxation and pulsed-gradient spin-echo (PGSE diffusion under variable temperature conditions. Synthetic (Laponite and natural (Swy-2 smectite clays, with different structural and physical parameters, were incorporated into the Nafion for the creation of exfoliated nanocomposites. Transport mechanism of water and methanol appears to be influenced from the dimensions of the dispersed platelike silicate layers as well as from their cation exchange capacity (CEC. The details of the NMR results and the effect of the methanol solution concentration are discussed. Clays particles, and in particular Swy-2, demonstrate to be a potential physical barrier for methanol cross-over, reducing the methanol diffusion with an evident blocking effect yet nevertheless ensuring a high water mobility up to 130 °C and for several hours, proving the exceptional water retention property of these materials and their possible use in the DMFCs applications. Electrochemical behavior is investigated by cell resistance and polarization measurements. From these analyses it is derived that the addition of clay materials to recast Nafion decreases the ohmic losses at high temperatures extending in this way the operating range of a direct methanol fuel cell.

  1. A rapid procedure for the in situ assay of periplasmic, PQQ-dependent methanol dehydrogenase in intact single bacterial colonies.

    Science.gov (United States)

    Vemuluri, Venkata Ramana; Shaw, Shreya; Autenrieth, Caroline; Ghosh, Robin

    2017-03-23

    Mechanistic details of methanol oxidation catalyzed by the periplasmically-located pyrroloquinoline quinone-dependent methanol dehydrogenase of methylotrophs can be elucidated using site-directed mutants. Here, we present an in situ colony assay of methanol dehydrogenase, which allows robotic screening of large populations of intact small colonies, and regrowth of colonies for subsequent analysis.

  2. Studies of methanol maser rings

    CERN Document Server

    Bartkiewicz, A; van Langevelde, H J; De Buizer, J M; Pihlström, Y

    2011-01-01

    We present the results of studies of a new class of 6.7 GHz methanol maser sources with a ring-like emission structure discovered recently with the EVN. We have used the VLA to search for water masers at 22 GHz and radio continuum at 8.4 GHz towards a sample of high-mass star forming regions showing a ring-like distribution of methanol maser spots. Using the Gemini telescopes we found mid-infrared (MIR) counterparts of five methanol rings with a resolution of 0."15. The centres of methanol maser rings are located within, typically, only 0."2 of the MIR emission peak, implying their physical relation with a central star. These results strongly support a scenario wherein the ring-like structures appear at the very early stage of massive star formation before either water-maser outflows or H II regions are seen.

  3. Short Review: Mitigation of Current Environmental Concerns from Methanol Synthesis

    Directory of Open Access Journals (Sweden)

    Andrew Young

    2013-06-01

    Full Text Available Methanol has become a widely used and globally distributed product. Methanol is very important due to the current depletion of fossil fuels. Industrially, methanol produced from the catalytic reaction of synthetic gas composed of hydrogen, carbon monoxide, and carbon dioxide. Methanol production has brought great attention due to carbon dioxide as the main source of greenhouse gas emissions. Combined of reducing CO2 emissions and supplying an alternative fuel source has created the idea of a carbon neutral cycle called “the methanol economy”. The best catalyst for the methanol economy would show a high CO2 conversion and high selectivity for methanol production. This paper investigates research focused on catalyst development for efficient methanol synthesis from hydrogenation of carbon dioxide through added various supports and additives such as silica, zirconium, and palladium. Catalysts that displayed the highest activity included a zirconia and silicon-titanium oxide promoted Cu/Zn/Al2O3 catalyst. Alternative method of catalyst preparation, include the oxalate-gel, solid-state reaction, co-precipitation and combustion method also investigated.  © 2013 BCREC UNDIP. All rights reservedReceived: 10th October 2012; Revised: 7th February 2012; Accepted: 10th February 2013[How to Cite: Young, A., Lesmana, D., Dai, D.J., Wu, H.S. (2013. Short Review: Mitigation of Current En-vironmental Concerns from Methanol Synthesis. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 1-13. (doi:10.9767/bcrec.8.1.4055.1-13][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4055.1-13] | View in  |

  4. New constraints on terrestrial and oceanic sources of atmospheric methanol

    Directory of Open Access Journals (Sweden)

    D. B. Millet

    2008-12-01

    Full Text Available We use a global 3-D chemical transport model (GEOS-Chem to interpret new aircraft, surface, and oceanic observations of methanol in terms of the constraints that they place on the atmospheric methanol budget. Recent measurements of methanol concentrations in the ocean mixed layer (OML imply that in situ biological production must be the main methanol source in the OML, dominating over uptake from the atmosphere. It follows that oceanic emission and uptake must be viewed as independent terms in the atmospheric methanol budget. We deduce that the marine biosphere is a large primary source (85 Tg a−1 of methanol to the atmosphere and is also a large sink (101 Tg a−1, comparable in magnitude to atmospheric oxidation by OH (88 Tg a−1. The resulting atmospheric lifetime of methanol in the model is 4.7 days. Aircraft measurements in the North American boundary layer imply that terrestrial plants are a much weaker source than presently thought, likely reflecting an overestimate of broadleaf tree emissions, and this is also generally consistent with surface measurements. We deduce a terrestrial plant source of 80 Tg a−1, comparable in magnitude to the ocean source. The aircraft measurements show a strong correlation with CO (R2=0.51−0.61 over North America during summer. We reproduce this correlation and slope in the model with the reduced plant source, which also confirms that the anthropogenic source of methanol must be small. Our reduced plant source also provides a better simulation of methanol observations over tropical South America.

  5. Hepatoprotective activity of the methanolic extract of Tylophora indica (Burm. f. Merill. leaves

    Directory of Open Access Journals (Sweden)

    Mujeeb M

    2009-01-01

    Full Text Available The methanolic extract of Tylophora indica leaves was screened for hepatoprotective activity in carbon tetrachloride induced hepatotoxicity in albino rats. The degree of protection was measured by estimating biochemical parameters like Serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, total protein and level of serum bilirubin (both total and direct. Hepatoprotective activity of methanolic extract at a dose of 200 mg/kg and 300 mg/kg body weight, i.p., was compared with Silymarin (25 mg/kg, i.p. treated animals. Tylophora indica leaves (200 and 300 mg/kg exhibited significant reduction in serum hepatic enzymes when compared to rats treated with carbon tetrachloride alone. Furthermore, histopathological studies were also done to support the study.

  6. C-terminal methylation of truncated neuropeptides: an enzyme-assisted extraction artifact involving methanol.

    Science.gov (United States)

    Stemmler, Elizabeth A; Barton, Elizabeth E; Esonu, Onyinyechi K; Polasky, Daniel A; Onderko, Laura L; Bergeron, Audrey B; Christie, Andrew E; Dickinson, Patsy S

    2013-08-01

    Neuropeptides are the largest class of signaling molecules used by nervous systems. Today, neuropeptide discovery commonly involves chemical extraction from a tissue source followed by mass spectrometric characterization. Ideally, the extraction procedure accurately preserves the sequence and any inherent modifications of the native peptides. Here, we present data showing that this is not always true. Specifically, we present evidence showing that, in the lobster Homarus americanus, the orcokinin family members, NFDEIDRSGFG-OMe and SSEDMDRLGFG-OMe, are non-native peptides generated from full-length orcokinin precursors as the result of a highly selective peptide modification (peptide truncation with C-terminal methylation) that occurs during extraction. These peptides were observed by MALDI-FTMS and LC-Q-TOFMS analyses when eyestalk ganglia were extracted in a methanolic solvent, but not when tissues were dissected, co-crystallized with matrix, and analyzed directly with methanol excluded from the sample preparation. The identity of NFDEIDRSGFG-OMe was established using MALDI-FTMS/SORI-CID, LC-Q-TOFMS/MS, and comparison with a peptide standard. Extraction substituting deuterated methanol for methanol confirmed that the latter is the source of the C-terminal methyl group, and MS/MS confirmed the C-terminal localization of the added CD3. Surprisingly, NFDEIDRSGFG-OMe is not produced via a chemical acid-catalyzed esterification. Instead, the methylated peptide appears to result from proteolytic truncation in the presence of methanol, as evidenced by a reduction in conversion with the addition of a protease-inhibitor cocktail; heat effectively eliminated the conversion. This unusual and highly specific extraction-derived peptide conversion exemplifies the need to consider both chemical and biochemical processes that may modify the structure of endogenous neuropeptides.

  7. Liquid Methanol from DFT and DFT/MM Molecular Dynamics Simulations.

    Science.gov (United States)

    Sieffert, Nicolas; Bühl, Michael; Gaigeot, Marie-Pierre; Morrison, Carole A

    2013-01-08

    We present a comparative study of computational protocols for the description of liquid methanol from ab initio molecular dynamics simulations, in view of further applications directed at the modeling of chemical reactivity of organic and organometallic molecules in (explicit) methanol solution. We tested density functional theory molecular dynamics (DFT-MD) in its Car-Parrinello Molecular Dynamics (CPMD) and Quickstep/Born-Oppenheimer MD (CP2K) implementations, employing six popular density functionals with and without corrections for dispersion interactions (namely BLYP, BLYP-D2, BLYP-D3, BP86, BP86-D2, and B97-D2). Selected functionals were also tested within the two QM/MM frameworks implemented in CPMD and CP2K, considering one DFT molecule in a MM environment (described by the OPLS model of methanol). The accuracy of each of these methods at describing the bulk liquid phase under ambient conditions was evaluated by analyzing their ability to reproduce (i) the average structure of the liquid, (ii) the mean squared displacement of methanol molecules, (iii) the average molecular dipole moments, and (iv) the gas-to-liquid red-shift observed in their infrared spectra. We show that it is difficult to find a DFT functional that describes these four properties equally well within full DFT-MD simulations, despite a good overall performance of B97-D2. On the other hand, DFT/MM-MD provides a satisfactory description of the solvent-solute polarization effects with all functionals and thus represents a good alternative for the modeling of methanol solutions in the context of chemical reactivity in an explicit environment.

  8. Acute methanol toxicity in minipigs

    Energy Technology Data Exchange (ETDEWEB)

    Dorman, D.C.; Dye, J.A.; Nassise, M.P.; Ekuta, J.; Bolon, B.

    1993-01-01

    The pig has been proposed as a potential animal model for methanol-induced neuro-ocular toxicosis in humans because of its low liver tetrahydrofolate levels and slower rate of formate metabolism compared to those of humans. To examine the validity of this animal model, 12 4-month-old female minipigs (minipig YU) were given a single oral dose of water or methanol at 1.0, 2.5, or 5.0 g/kg body wt by gavage (n = 3 pigs/dose). Dose-dependent signs of acute methanol intoxication, which included mild CNS depression, tremors, ataxia, and recumbency, developed within 0.5 to 2.0 hr, and resolved by 52 hr. Methanol- and formate-dosed pigs did not develop optic nerve lesions, toxicologically significant formate accumulation, or metabolic acidosis. Based on results following a single dose, female minipigs do not appear to be overtly sensitive to methanol and thus may not be a suitable animal model for acute methanol-induced neuroocular toxicosis.

  9. Liquid methanol under a static electric field

    Energy Technology Data Exchange (ETDEWEB)

    Cassone, Giuseppe, E-mail: giuseppe.cassone@impmc.upmc.fr [Sorbonne Universités, UPMC Univ Paris 06, UMR 7590, IMPMC, F-75005 Paris (France); CNRS, UMR 7590, IMPMC, F-75005 Paris (France); Università degli Studi di Messina, Dipartimento di Fisica e di Scienze della Terra, Contrada Papardo, 98166 Messina (Italy); CNR-IPCF, Viale Ferdinando Stagno d’Alcontres 37, 98158 Messina (Italy); Giaquinta, Paolo V., E-mail: paolo.giaquinta@unime.it [Università degli Studi di Messina, Dipartimento di Fisica e di Scienze della Terra, Contrada Papardo, 98166 Messina (Italy); Saija, Franz, E-mail: saija@ipcf.cnr.it [CNR-IPCF, Viale Ferdinando Stagno d’Alcontres 37, 98158 Messina (Italy); Saitta, A. Marco, E-mail: marco.saitta@impmc.upmc.fr [Sorbonne Universités, UPMC Univ Paris 06, UMR 7590, IMPMC, F-75005 Paris (France); CNRS, UMR 7590, IMPMC, F-75005 Paris (France)

    2015-02-07

    We report on an ab initio molecular dynamics study of liquid methanol under the effect of a static electric field. We found that the hydrogen-bond structure of methanol is more robust and persistent for field intensities below the molecular dissociation threshold whose value (≈0.31 V/Å) turns out to be moderately larger than the corresponding estimate obtained for liquid water. A sustained ionic current, with ohmic current-voltage behavior, flows in this material for field intensities above 0.36 V/Å, as is also the case of water, but the resulting ionic conductivity (≈0.40 S cm{sup −1}) is at least one order of magnitude lower than that of water, a circumstance that evidences a lower efficiency of proton transfer processes. We surmise that this study may be relevant for the understanding of the properties and functioning of technological materials which exploit ionic conduction, such as direct-methanol fuel cells and Nafion membranes.

  10. Electrochemical oxidation of methanol on Pt3Co bulk alloy

    Directory of Open Access Journals (Sweden)

    S. LJ. GOJKOVIC

    2003-11-01

    Full Text Available The electrochemical oxidation of methanol was investigated on a Pt3Co bulk alloy in acid solutions. Kinetic parameters such as transfer coefficient, reaction orders with respect to methanol and H+ ions and energy of activation were determined. It was found that the rate of methanol oxidation is significantly diminished by rotation of the electrode. This effect was attributed to the diffusion of formaldehyde and formic acid from the electrode surface. Stirring of the electrolyte also influenced the kinetic parameters of the reaction. It was speculated that the predominant reaction pathway and rate determining step are different in the quiescent and in the stirred electrolyte. Cobalt did not show a promoting effect on the rate of methanol oxidation on the Pt3Co bulk alloy with respect to a pure Pt surface.

  11. Dietary methanol regulates human gene activity.

    Directory of Open Access Journals (Sweden)

    Anastasia V Shindyapina

    Full Text Available Methanol (MeOH is considered to be a poison in humans because of the alcohol dehydrogenase (ADH-mediated conversion of MeOH to formaldehyde (FA, which is toxic. Our recent genome-wide analysis of the mouse brain demonstrated that an increase in endogenous MeOH after ADH inhibition led to a significant increase in the plasma MeOH concentration and a modification of mRNA synthesis. These findings suggest endogenous MeOH involvement in homeostasis regulation by controlling mRNA levels. Here, we demonstrate directly that study volunteers displayed increasing concentrations of MeOH and FA in their blood plasma when consuming citrus pectin, ethanol and red wine. A microarray analysis of white blood cells (WBC from volunteers after pectin intake showed various responses for 30 significantly differentially regulated mRNAs, most of which were somehow involved in the pathogenesis of Alzheimer's disease (AD. There was also a decreased synthesis of hemoglobin mRNA, HBA and HBB, the presence of which in WBC RNA was not a result of red blood cells contamination because erythrocyte-specific marker genes were not significantly expressed. A qRT-PCR analysis of volunteer WBCs after pectin and red wine intake confirmed the complicated relationship between the plasma MeOH content and the mRNA accumulation of both genes that were previously identified, namely, GAPDH and SNX27, and genes revealed in this study, including MME, SORL1, DDIT4, HBA and HBB. We hypothesized that human plasma MeOH has an impact on the WBC mRNA levels of genes involved in cell signaling.

  12. Unusual case of methanol poisoning

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, L.; Henderson, M. (St. James' s Univ. Hospital, Leeds (United Kingdom). Dept. of Chemical Pathology); Madi, S.; Mellor, L. (St. James' s Univ. Hospital, Leeds (United Kingdom). Dept. of Medicine, and Pharmacy)

    1993-01-09

    A 31-year-old man with a history of alcohol abuse presented to the accident and emergency department complaining of blurred vision. 4 h previously he had drunk 300 mL de-icer fluid. Electrolytes, urea, creatinine, glucose, and blood-gas analysis were normal. Measured osmolality, however, was 368 mosmol/kg with a calculated osmolality of 300 mosmol/kg, which indicated a greatly increased osmolar gap. He was therefore given 150 mL whisky and admitted. Methanol was later reported as 200 mg/dL. Ethylene glycol was not detected, but another glycol, propylene glycol, was present at 47 mg/dL. 10 h after ingestion an intravenous infusion of ethanol was started and he was hemodialysed for 7 h. After dialysis he was given a further 100 mL whisky and the rate of ethanol infusion was reduced to 11 g per h. Methanol and ethanol were measured twice daily until methanol was under 10/mg/dL: The recommendation is that blood ethanol be maintained between 100 and 200 mg/dL during treatment of methanol poisoning. This concentration was not achieved, presumably because of the high rate of ethanol metabolism often found in alcoholics. Antifreeze solutions commonly contain methanol and ethylene glycol. Sometimes propylene glycol is substituted because it has properties similar to those of ethylene glycol but is less toxic. The authors postulate that propylene glycol inhibited the metabolism of methanol in the patient, thus sparing him from the toxic effects of methanol.

  13. [Study on the method for the determination of trace boron, molybdenum, silver, tin and lead in geochemical samples by direct current arc full spectrum direct reading atomic emission spectroscopy (DC-Arc-AES)].

    Science.gov (United States)

    Hao, Zhi-hong; Yao, Jian-zhen; Tang, Rui-ling; Zhang, Xue-mei; Li, Wen-ge; Zhang, Qin

    2015-02-01

    The method for the determmation of trace boron, molybdenum, silver, tin and lead in geochemical samples by direct current are full spectrum direct reading atomic emission spectroscopy (DC-Arc-AES) was established. Direct current are full spectrum direct reading atomic emission spectrometer with a large area of solid-state detectors has functions of full spectrum direct reading and real-time background correction. The new electrodes and new buffer recipe were proposed in this paper, and have applied for national patent. Suitable analytical line pairs, back ground correcting points of elements and the internal standard method were selected, and Ge was used as internal standard. Multistage currents were selected in the research on current program, and each current set different holding time to ensure that each element has a good signal to noise ratio. Continuous rising current mode selected can effectively eliminate the splash of the sample. Argon as shielding gas can eliminate CN band generating and reduce spectral background, also plays a role in stabilizing the are, and argon flow 3.5 L x min(-1) was selected. Evaporation curve of each element was made, and it was concluded that the evaporation behavior of each element is consistent, and combined with the effects of different spectrographic times on the intensity and background, the spectrographic time of 35s was selected. In this paper, national standards substances were selected as a standard series, and the standard series includes different nature and different content of standard substances which meet the determination of trace boron, molybdenum, silver, tin and lead in geochemical samples. In the optimum experimental conditions, the detection limits for B, Mo, Ag, Sn and Pb are 1.1, 0.09, 0.01, 0.41, and 0.56 microg x g(-1) respectively, and the precisions (RSD, n=12) for B, Mo, Ag, Sn and Pb are 4.57%-7.63%, 5.14%-7.75%, 5.48%-12.30%, 3.97%-10.46%, and 4.26%-9.21% respectively. The analytical accuracy was

  14. Enhanced methanol production in plants provides broad spectrum insect resistance.

    Directory of Open Access Journals (Sweden)

    Sameer Dixit

    Full Text Available Plants naturally emit methanol as volatile organic compound. Methanol is toxic to insect pests; but the quantity produced by most of the plants is not enough to protect them against invading insect pests. In the present study, we demonstrated that the over-expression of pectin methylesterase, derived from Arabidopsis thaliana and Aspergillus niger, in transgenic tobacco plants enhances methanol production and resistance to polyphagous insect pests. Methanol content in the leaves of transgenic plants was measured using proton nuclear spectroscopy (1H NMR and spectra showed up to 16 fold higher methanol as compared to control wild type (WT plants. A maximum of 100 and 85% mortality in chewing insects Helicoverpa armigera and Spodoptera litura larvae was observed, respectively when fed on transgenic plants leaves. The surviving larvae showed less feeding, severe growth retardation and could not develop into pupae. In-planta bioassay on transgenic lines showed up to 99 and 75% reduction in the population multiplication of plant sap sucking pests Myzus persicae (aphid and Bemisia tabaci (whitefly, respectively. Most of the phenotypic characters of transgenic plants were similar to WT plants. Confocal microscopy showed no deformities in cellular integrity, structure and density of stomata and trichomes of transgenic plants compared to WT. Pollen germination and tube formation was also not affected in transgenic plants. Cell wall enzyme transcript levels were comparable with WT. This study demonstrated for the first time that methanol emission can be utilized for imparting broad range insect resistance in plants.

  15. Scaledown of a methanol reactor

    Energy Technology Data Exchange (ETDEWEB)

    Berty, J.M.

    1983-07-01

    This article shows how it is possible to define operating conditions for pilot plants and development labs by scaling down a commercial reactor. Points out that scaledown consideration and experiment planning can be done in a similar manner for the boiling water-cooled, Lurgi-type reactor. Explains that although the design of large, single-train plants to produce methanol for fuel use has different economic objectives, product specifications, and technical constraints from the traditional commercial methanol plants, the same fundamental laws of thermodynamics and reaction kinetics apply to both types of operation.

  16. Highly methanol-tolerant platinum electrocatalyst derived from poly(vinylpoyrrolidone) coating

    Science.gov (United States)

    Yang, Zehui; Ling, Ying; Zhang, Yunfeng; Yang, Ming

    2017-02-01

    The design and fabrication of a methanol-tolerant electrocatalyst is still one of the most important issues in direct methanol fuel cells (DMFCs). Here, we focus on the design of a cathodic electrocatalyst in DMFCs and describe a new methanol-tolerant electrocatalyst fabricated from poly(vinylpyrrolidone) (PVP) coating on platinum nanoparticles assisted by hydrogen bonding between PVP and polybenzimidazole (PBI). The PVP layer has a negligible effect on the oxygen reduction reaction (ORR) activity, while the methanol oxidation reaction is retarded by the PVP layer. The PVP-coated electrocatalyst shows higher ORR activity under various methanol concentrations in the electrolyte, suggesting that the PVP-coated electrocatalyst has a higher methanol tolerance. Also, the PVP-coated electrocatalyst loses only 14% of the electrochemical surface area after 5000 potential cycles from 0.6-1.0 V versus the reversible hydrogen electrode, indicating better Pt stability than non-coated (27%) and commercial (38%) electrocatalysts due to the unique sandwich structure formed by the PVP and PBI. The power density of the PVP-coated electrocatalyst is four to five times higher compared to non-coated and commercial electrocatalysts with 12 M methanol feeding to the anode side, respectively. PVP coating is important for the enhancement of Pt stability and methanol tolerance. This study offers a new method for preparing a low-cost and high-methanol-tolerant Pt electrocatalyst, and useful information for real DMFC application to eliminate the methanol crossover problem in the cathode side.

  17. A 30 Gb/s full-duplex bi-directional transmission optical wireless-over fiber integration system at W-band.

    Science.gov (United States)

    Tang, Chanjuan; Yu, Jianjun; Li, Xinying; Chi, Nan; Xiao, Jiangnan; Tian, Yumin; Zhang, Junwen

    2014-01-13

    We propose and experimentally demonstrate a full-duplex bi-directional transmission optical wireless-over fiber integration system at W-band (75-100 GHz) with the speed up to 15 Gb/s for both 95.4 GHz link and 88.6 GHz link for the first time. The generation of millimeter-wave (mm-wave) wireless signal is based on the photonic technique by heterodyne mixing of an optical quadrature-phase-shift-keying (QPSK) signal with a free-running light at different wavelength. After 20 km fiber transmission, up to 30 Gb/s mm-wave signal is delivered over 2 m wireless link, and then converted to the optical signal for another 20 km fiber transmission. At the wireless receiver, coherent detection and advanced digital signal processing (DSP) are introduced to improve receiver sensitivity and system performance. With the OSNR of 15 dB, the bit error ratios (BERs) for 10 Gb/s signal transmission at 95.4 GHz and 88.6 GHz are below the forward-error-correction (FEC) threshold of 3.8 × 10(-3) whether post filter is used or not, while the BER for 15 Gb/s QPSK signal employing post filter in the link of 95.4 GHz is 2.9 × 10(-3).

  18. Pathways of methanol conversion in a thermophilic anaerobic (55 degrees C) sludge consortium

    NARCIS (Netherlands)

    Paulo, P.L.; Stams, A.J.M.; Field, J.A.; Dijkema, C.; Lier, van J.B.; Lettinga, G.

    2003-01-01

    The pathway of methanol conversion by a thermophilic anaerobic consortium was elucidated by recording the fate of carbon in the presence and absence of bicarbonate and specific inhibitors. Results indicated that about 50% of methanol was directly converted to methane by the methylotrophic

  19. Discovery of a Ni-Ga catalyst for carbon dioxide reduction to methanol

    DEFF Research Database (Denmark)

    Studt, Felix; Sharafutdinov, Irek; Abild-Pedersen, Frank

    2014-01-01

    The use of methanol as a fuel and chemical feedstock could become very important in the development of a more sustainable society if methanol could be efficiently obtained from the direct reduction of CO 2 using solar-generated hydrogen. If hydrogen production is to be decentralized, small-scale ...

  20. Pathways of methanol conversion in a thermophilic anaerobic (55 degrees C) sludge consortium

    NARCIS (Netherlands)

    Paulo, P.L.; Stams, A.J.M.; Field, J.A.; Dijkema, C.; Lier, van J.B.; Lettinga, G.

    2003-01-01

    The pathway of methanol conversion by a thermophilic anaerobic consortium was elucidated by recording the fate of carbon in the presence and absence of bicarbonate and specific inhibitors. Results indicated that about 50% of methanol was directly converted to methane by the methylotrophic methanogen

  1. Physical characteristics of bright Class I methanol masers

    Science.gov (United States)

    Leurini, S.; Menten, K. M.; Walmsley, C. M.

    2016-07-01

    Context. Class I methanol masers are thought to be tracers of interstellar shock waves. However, they have received relatively little attention mostly as a consequence of their low luminosities compared to other maser transitions. This situation has changed recently and Class I methanol masers are now routinely used as signposts of outflow activity especially in high extinction regions. The recent detection of polarisation in Class I lines now makes it possible to obtain direct observational information about magnetic fields in interstellar shocks. Aims: We make use of newly calculated collisional rate coefficients for methanol to investigate the excitation of Class I methanol masers and to reconcile the observed Class I methanol maser properties with model results. Methods: We performed large velocity gradient calculations with a plane-parallel slab geometry appropriate for shocks to compute the pump and loss rates which regulate the interactions of the different maser systems with the maser reservoir. We study the dependence of the pump rate coefficient, the maser loss rate, and the inversion efficiency of the pumping scheme of several Class I masers on the physics of the emitting gas. Results: We predict inversion in all transitions where maser emission is observed. Bright Class I methanol masers are mainly high-temperature (>100 K) high-density (n(H2) ~ 107-108 cm-3) structures with methanol maser emission measures, ξ, corresponding to high methanol abundances close to the limits set by collisional quenching. Our model predictions reproduce reasonably well most of the observed properties of Class I methanol masers. Class I masers in the 25 GHz series are the most sensitive to the density of the medium and mase at higher densities than other lines. Moreover, even at high density and high methanol abundances, their luminosity is predicted to be lower than that of the 44 GHz and 36 GHz masers. Our model predictions also reflect the observational result that the

  2. PERFORMANCE AND EMISSION STUDIES ON DI-DIESEL ENGINE FUELED WITH PONGAMIA METHYL ESTER INJECTION AND METHANOL CARBURETION

    Directory of Open Access Journals (Sweden)

    HARIBABU, N.

    2010-03-01

    Full Text Available The target of the present study is to clarify ignition characteristics, combustion process and knock limit of methanol premixture in a dual fuel diesel engine, and also to improve the trade-off between NOx and smoke markedly without deteriorating the high engine performance. Experiment was conducted to evaluate the performance and emission characteristics of direct injection diesel engine operating in duel fuel mode using Pongamia methyl ester injection and methanol carburetion. Methanol is introduced into the engine at different throttle openings along with intake air stream by a carburetor which is arranged at bifurcated air inlet. Pongamia methyl ester fuel was supplied to the engine by conventional fuel injection. The experimental results show that exhaust gas temperatures are moderate and there is better reduction of NOx, HC, CO and CO2 at methanol mass flow rate of 16.2 mg/s. Smoke level was observed to be low and comparable. Improved thermal efficiency of the engine was observed.

  3. Adsorption of Methanol and Methoxy on Cu(111) Surface: A First-principles Periodic Density Functional Theory Study

    Institute of Scientific and Technical Information of China (English)

    CHEN, Wen-Kai; LIU, Shu-Hong; CAO, Mei-Juan; LU, Chun-Hai; XU, Ying; LI, Jun-Qian

    2006-01-01

    Adsorption of methanol and methoxy at four selected sites (top, bridge, hcp, fcc) on Cu(111) surface has been investigated by density functional theory method at the generalized gradient approximation (GGA) level. The calculation on adsorption energies, geometry and electronic structures, Mulliken charges, and vibrational frequencies of CH3OH and CH3O on clean Cu(111) surface was performed with full-geometry optimization, and compared with the experimental data. The obtained results are in agreement with available experimental data. The most favorite adsorption site for methanol on Cu(111) surface is the top site, where C-O axis is tilted to the surface. Moreover,the preferred adsorption site for methoxy on Cu(111) surface is the fcc site, and it adsorbs in an upright geometry with pseudo-C3v local symmetry. Possible decomposition pathways also have been investigated by transition-state searching methods. Methoxy radical, CH3O, was found to be the decomposition intermediate. Methanol can be adsorbed on the surface with its oxygen atom directly on a Cu atom, and weakly chemisorbed on Cu(111) surface. In contrast to methanol, methoxy is strongly chemisorbed to the surface.

  4. Towards a methanol economy based on homogeneous catalysis: methanol to H2 and CO2 to methanol

    DEFF Research Database (Denmark)

    Alberico, E.; Nielsen, Martin

    2015-01-01

    The possibility to implement both the exhaustive dehydrogenation of aqueous methanol to hydrogen and CO2 and the reverse reaction, the hydrogenation of CO2 to methanol and water, may pave the way to a methanol based economy as part of a promising renewable energy system. Recently, homogeneous...

  5. Sensitivity of a direct computer-aided detection system in full-field digital mammography for detection of microcalcifications not associated with mass or architectural distortion.

    Science.gov (United States)

    Scaranelo, Anabel M; Crystal, Pavel; Bukhanov, Karina; Helbich, Thomas H

    2010-06-01

    The purpose of this study was to evaluate the sensitivity of a direct computer-aided detection (CAD) system (d-CAD) in full-field digital mammography (FFDM) for the detection of microcalcifications not associated with mass or architectural distortion. A database search of 1063 consecutive stereotactic core biopsies performed between 2002 and 2005 identified 196 patients with Breast Imaging-Reporting and Data System (BI-RADS) 4 and 5 microcalcifications not associated with mass or distortion detected exclusively by bilateral FFDM. A commercially available CAD system (Second Look, version 7.2) was retrospectively applied to the craniocaudal and mediolateral oblique views in these patients (mean age, 59 years; range, 35-84 years). Breast density, location and mammographic size of the lesion, distribution, and tumour histology were recorded and analysed by using chi(2), Fisher exact, or McNemar tests, when applicable. When using d-CAD, 71 of 74 malignant microcalcification cases (96%) and 101 of 122 benign microcalcifications (83%) were identified. There was a significant difference (P < .05) between CAD sensitivity on the craniocaudal view, 91% (68 of 75), vs CAD sensitivity on the mediolateral oblique view, 80% (60 of 75). The d-CAD sensitivity for dense breast tissue (American College of Radiology [ACR] density 3 and 4) was higher (97%) than d-CAD sensitivity (95%) for nondense tissue (ACR density 1 and 2), but the difference was not statically significant. All 28 malignant calcifications larger than 10 mm were detected by CAD, whereas the sensitivity for lesions small than or equal to 10 mm was 94%. D-CAD had a high sensitivity in the depiction of asymptomatic breast cancers, which were seen as microcalcifications on FFDM screening, with a sensitivity of d-CAD on the craniocaudal view being significantly better. All malignant microcalcifications larger than 10 mm were detected by d-CAD. Copyright 2010 Canadian Association of Radiologists. Published by Elsevier Inc

  6. TALENs-directed knockout of the full-length transcription factor Nrf1α that represses malignant behaviour of human hepatocellular carcinoma (HepG2) cells.

    Science.gov (United States)

    Ren, Yonggang; Qiu, Lu; Lü, Fenglin; Ru, Xufang; Li, Shaojun; Xiang, Yuancai; Yu, Siwang; Zhang, Yiguo

    2016-04-11

    The full-length Nrf1α is processed into distinct isoforms, which together regulate genes essential for maintaining cellular homeostasis and organ integrity, and liver-specific loss of Nrf1 in mice results in spontaneous hepatoma. Herein, we report that the human constitutive Nrf1α, rather than smaller Nrf1β/γ, expression is attenuated or abolished in the case of low-differentiated high-metastatic hepatocellular carcinomas. Therefore, Nrf1α is of importance in the physio-pathological origin and development, but its specific pathobiological function(s) remains elusive. To address this, TALENs-directed knockout of Nrf1α, but not Nrf1β/γ, is created in the human hepatocellular carcinoma (HepG2) cells. The resulting Nrf1α(-/-) cells are elongated, with slender spindle-shapes and enlarged gaps between cells observed under scanning electron microscope. When compared with wild-type controls, the invasive and migratory abilities of Nrf1α(-/-) cells are increased significantly, along with the cell-cycle G2-M arrest and S-phase reduction, as accompanied by suppressed apoptosis. Despite a modest increase in the soft-agar colony formation of Nrf1α(-/-) cells, its loss-of-function markedly promotes malgrowth of the subcutaneous carcinoma xenograft in nude mice with hepatic metastasis. Together with molecular expression results, we thus suppose requirement of Nrf1α (and major derivates) for gene regulatory mechanisms repressing cancer cell process (e.g. EMT) and malignant behaviour (e.g. migration).

  7. A Techno-Economic Comparison between Two Methanol-to-Propylene Processes

    Directory of Open Access Journals (Sweden)

    Sarah Jasper

    2015-09-01

    Full Text Available The significant increase in natural/shale gas production in the US is causing major changes in the chemical and petrochemical markets. These changes include the increased supply of methanol and the decreased supply of propylene. As such, there are promising opportunities for methanol-to-propylene processes in the US. This paper provides a top-level techno-economic analysis of two pathways: methanol to olefins (MTO and methanol to propylene (MTP. Base-case scenarios are simulated using ASPEN Plus to obtain the key mass and energy balances as well as design data. For each process, two scenarios are considered for the feedstock: buying methanol versus making it from natural gas. The return on investment (ROI is calculated for both processes under broad ranges of the prices of natural gas, methanol, and products. In addition to the techno-economic analysis, the CO2 emissions are evaluated and compared.

  8. Simultaneous production of methanol and dimethylether from synthesis gas

    OpenAIRE

    Akarmazyan, Siranush

    2015-01-01

    Dimethylether is a non-toxic liquefied gas, which is projected to become one of the fundamental chemical feedstock in the future. Dimethylether can be produced from syngas via a two-step (indirect) process that involves synthesis of methanol by hydrogenation of CO/CO2 over a copper based catalyst and subsequent dehydration of methanol to DME over an acidic catalyst. Alternatively, DME can be produced in an one-step (direct) process using a hybrid (bifunctional) catalyst system that permits bo...

  9. Thermal Effusivity Measurement of Virgin Coconut Oil-Methanol Mixtures using Photoacoustic Technique

    Directory of Open Access Journals (Sweden)

    Firas K.M. Al-asfoor

    2008-01-01

    Full Text Available Thermal effusivity of virgin coconut oil-methanol mixtures were measured using open photoacoustic cell technique. The samples were prepared by simply mixing virgin coconut oil and methanol using similar procedure applied for preparation of biodisel. Thermal effusivity of the sample was obtained by fitting the experimental data of photoacoustic amplitude signal to the expression of photoacoustic signal as a function of chopping frequency. Thermal effusivity of mixtures decrease between 0.0851 W s1/2 K-1 cm-2 (pure virgin coconut oil and 0.0644 W s1/2 K-1 cm-2 (pure methanol with the increasing of methanol in the mixture.

  10. Fermentation of methanol in the sheep rumen.

    OpenAIRE

    Pol, A.; Demeyer, D. I.

    1988-01-01

    Sheep fed a hay-concentrate diet were adapted to pectin administration and ruminal infusion of methanol. Both treatments resulted in a strong increase in the rate of methanogenesis from methanol. Quantitative data show that methanol was exclusively converted into methane. Treatments did not influence ruminal volatile fatty acid percentages.

  11. The fate of methanol in anaerobic bioreactors

    NARCIS (Netherlands)

    Florencio, L.

    1994-01-01

    Methanol is an important component of certain industrial wastewaters. In anaerobic environments, methanol can be utilized by methanogens and acetogens. In wastewater treatment plants, the conversion of methanol into methane is preferred because this conversion is responsible for chemical

  12. The fate of methanol in anaerobic bioreactors.

    NARCIS (Netherlands)

    Florencio, L.

    1994-01-01

    Methanol is an important component of certain industrial wastewaters. In anaerobic environments, methanol can be utilized by methanogens and acetogens. In wastewater treatment plants, the conversion of methanol into methane is preferred because this conversion is responsible for chemical oxygen dema

  13. Methanol Uptake By Low Temperature Aqueous Sulfuric Acid Solutions

    Science.gov (United States)

    Iraci, Laura T.; Essin, Andrew M.; Golden, David M.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    To evaluate the role of upper tropospheric and lower stratospheric aerosols in the global budget of methanol, the solubility and reactivity of CH3OH in aqueous sulfuric acid solutions are under investigation. Using standard uptake techniques in a Knudsen cell reactor, we have measured the effective Henry's law coefficient, H(*), for methanol dissolution into 45 to 70 percent by weight H2SO4. We find that methanol solubility ranges from 10(exp 5) to 10(exp 8) M/atm and increases with decreasing temperature and with increasing sulfuric acid content. These solubility measurements include uptake due to physical solvation and all rapid equilibria which are established in solution. Our data indicate that simple uptake by aqueous sulfuric acid particles will not be a significant sink for methanol in the UT/LS. These results differ from those recently reported in the literature, and an explanation of this disparity will be presented. In addition to solvation, reaction between primary alcohols and sulfuric acid does occur, leading to the production of alkyl sulfates. Literature values for the rate of this reaction suggest that formation of CH3OSO3H may proceed in the atmosphere but is not significant under our experimental conditions. Results obtained using a complementary equilibrium measurement technique confirm this directly. In addition, the extent of methanol sequestration via formation of mono- and dimethylsulfate will be evaluated under several atmospheric conditions.

  14. Observations of the Zeeman effect in Class I methanol masers

    Science.gov (United States)

    Pratim Sarma, Anuj; Momjian, Emmanuel

    2017-01-01

    We present observations of the Zeeman effect in Class I methanol maser sources toward high mass star forming regions. Toward DR21(OH), we have detected the Zeeman effect at 44 GHz in a 219 Jy/beam maser centered at an LSR velocity of 0.83 km/s, and we find $zB_\\text{los} = 53.5 \\pm 2.7$ Hz. If 44 GHz methanol masers are excited at $10^{7-8}$ cm$^{-3}$, then magnetic fields in DR21(OH) should be ~10 mG. Our detected $zB_\\text{los}$ would then imply that the Zeeman splitting factor for the 44 GHz methanol maser line should be ~5 Hz/mG. Such small values for z would not be surprising, since the methanol molecule is non-paramagnetic, like H2O. Since there are no direct measurements or calculations of the 44 GHz methanol maser Zeeman splitting factor to date, such empirical attempts could prove valuable in building a repository of measurements from which to gain an understanding of the magnitude of z.

  15. Chemical oscillation in electrochemical oxidation of methanol on Pt surface

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on dual path reaction mechanism, a nonlinear dynamics model reflecting the potential oscilla- tion in electrooxidation of methanol on Pt surface was established. The model involves three variables, the electrode potential (e), the surface coverage of carbon monoxide (x), and adsorbed water (y). The chemical reactions and electrode potential were coupled together through the rate constant ki = exp(ai(e ? ei)). The analysis to the established model discloses the following: there are different kinetics be- haviors in different ranges of current densities. The chemical oscillation in methanol electrooxidation is assigned to two aspects, one from poison mediate CO of methanol electrooxidation, which is the in- duced factor of the chemical oscillation, and the other from the oxygen-containing species, such as H2Oa. The formation and disappearance of H2Oa deeply depend on the electrode potential, and directly cause the chemical oscillation. The established model makes clear that the potential oscillation in methanol electrooxidation is the result of the feedback of electrode potential e on the reactions in- volving poison mediates CO and oxygen-containing species H2Oa. The numerical analysis of the estab- lished model successfully explains why the potential oscillation in methanol galvanostatic oxidation on a Pt electrode only happens in a certain range of current densities but not at any current density.

  16. Chemical oscillation in electrochemical oxidation of methanol on Pt surface

    Institute of Scientific and Technical Information of China (English)

    LI LanLan; WEI ZiDong; QI XueQiang; SUN CaiXin; YIN GuangZhi

    2008-01-01

    Based on dual path reaction mechanism, a nonlinear dynamics model reflecting the potential oscilla-tion in electrooxidation of methanol on Pt surface was established. The model involves three variables, the electrode potential (e), the surface coverage of carbon monoxide (x), and adsorbed water (y). The chemical reactions and electrode potential were coupled together through the rate constant k1= exp(a e-e1)). The analysis to the established model discloses the following: there are different kinetics be-haviors in different ranges of current densities. The chemical oscillation in methanol electrooxidation is assigned to two aspects, one from poison mediate CO of methanol electrooxidallon, which is the in-duced factor of the chemical oscillation, and the other from the oxygen-containing species, such as H2Oa. The formation and disappearance of H2Oa deeply depend on the electrode potential, and directly cause the chemical oscillation. The established model makes clear that the potential oscillation in methanol electrooxidation is the result of the feedback of electrode potential e on the reactions in-volving poison mediates CO and oxygen-containing species H2Oa. The numerical analysis of the estab-lished model successfully explains why the potential oscillation in methanol galvanostatic oxidation on a Pt electrode only happens in a certain range of current densities but not at any current density.

  17. The Methanol Poisoning Outbreaks in Libya 2013 and Kenya 2014.

    Directory of Open Access Journals (Sweden)

    Morten Rostrup

    Full Text Available Outbreaks of methanol poisoning occur frequently on a global basis, affecting poor and vulnerable populations. Knowledge regarding methanol is limited, likely many cases and even outbreaks go unnoticed, with patients dying unnecessarily. We describe findings from the first three large outbreaks of methanol poisoning where Médecins Sans Frontières (MSF responded, and evaluate the benefits of a possible future collaboration between local health authorities, a Non-Governmental Organisation and international expertise.Retrospective study of three major methanol outbreaks in Libya (2013 and Kenya (May and July 2014. Data were collected from MSF field personnel, local health personnel, hospital files, and media reports.In Tripoli, Libya, over 1,000 patients were poisoned with a reported case fatality rate of 10% (101/1,066. In Kenya, two outbreaks resulted in approximately 341 and 126 patients, with case fatality rates of 29% (100/341 and 21% (26/126, respectively. MSF launched an emergency team with international experts, medications and equipment, however, the outbreaks were resolving by the time of arrival.Recognition of an outbreak of methanol poisoning and diagnosis seem to be the most challenging tasks, with significant delay from time of first presentations to public health warnings being issued. In spite of the rapid response from an emergency team, the outbreaks were nearly concluded by the time of arrival. A major impact on the outcome was not seen, but large educational trainings were conducted to increase awareness and knowledge about methanol poisoning. Based on this training, MSF was able to send a local emergency team during the second outbreak, supporting that such an approach could improve outcomes. Basic training, simplified treatment protocols, point-of-care diagnostic tools, and early support when needed, are likely the most important components to impact the consequences of methanol poisoning outbreaks in these challenging

  18. Reliability of pathogen control in direct potable reuse: Performance evaluation and QMRA of a full-scale 1 MGD advanced treatment train.

    Science.gov (United States)

    Pecson, Brian M; Triolo, Sarah C; Olivieri, Simon; Chen, Elise C; Pisarenko, Aleksey N; Yang, Chao-Chun; Olivieri, Adam; Haas, Charles N; Trussell, R Shane; Trussell, R Rhodes

    2017-10-01

    To safely progress toward direct potable reuse (DPR), it is essential to ensure that DPR systems can provide public health protection equivalent to or greater than that of conventional drinking water sources. This study collected data over a one-year period from a full-scale DPR demonstration facility, and used both performance distribution functions (PDFs) and quantitative microbial risk assessment (QMRA) to define and evaluate the reliability of the advanced water treatment facility (AWTF). The AWTF's ability to control enterovirus, Giardia, and Cryptosporidium was characterized using online monitoring of surrogates in a treatment train consisting of ozone, biological activated carbon, microfiltration, reverse osmosis, and ultraviolet light with an advanced oxidation process. This process train was selected to improve reliability by providing redundancy, defined as the provision of treatment beyond the minimum needed to meet regulatory requirements. The PDFs demonstrated treatment that consistently exceeded the 12/10/10-log thresholds for virus, Giardia, and Cryptosporidium, as currently required for potable reuse in California (via groundwater recharge and surface water augmentation). Because no critical process failures impacted pathogen removal performance during the yearlong testing, hypothetical failures were incorporated into the analysis to understand the benefit of treatment redundancy on performance. Each unit process was modeled with a single failure per year lasting four different failure durations: 15 min, 60 min, 8 h, and 24 h. QMRA was used to quantify the impact of failures on pathogen risk. The median annual risk of infection for Cryptosporidium was 4.9 × 10(-11) in the absence of failures, and reached a maximum of 1.1 × 10(-5) assuming one 24-h failure per process per year. With the inclusion of free chlorine disinfection as part of the treatment process, enterovirus had a median annual infection risk of 1.5 × 10(-14) (no failures

  19. Three-dimensional ordered macroporous platinum-based electrode for methanol oxidation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, three-dimensional ordered macroporous platinum catalysts with high real surface area were synthesized using the inverted colloidal crystals template technique and have been employed for the electrooxidation of methanol. The morphology and electrocatalytic behavior of the porous Pt electrodes were investigated with atomic force microscopy and electrochemical techniques. For the same amount of Pt deposited, the real surface areas of the electrodes are 9.16 and 8.00 cm2 for the porous electrodes with pore size of 320 and 500 nm respectively, which are more than 5 times larger than the directly deposited Pt electrode (1.4 cm2). The pore size effect on the methanol electrooxidation was investigated by testing low concentration solution of methanol and porous materials with different pore sizes. The synthesized macroporous Pt electrode shows high stability toward the electrooxidation of methanol and is promising for the direct methanol fuel cell.

  20. Silica based composite membranes for methanol fuel cells operating at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, A.; Guzman, C.; Peza-Ledesma, C.; Godinez, Luis A.; Nava, R.; Duron-Torres, S.M.; Ledesma-Garcia, J.; Arriaga, L.G.

    2011-01-15

    Direct methanol fuel cells (DMFCs) are seen as an alternative energy source for several applications, particularly portable power sources. Nafion membranes constitute a well known proton exchange system for DMFC systems due to their convenient electrochemical, mechanical and thermal stability and high proton conductivity properties. But there are problems currently associated with the direct methanol fuel cell technology. Intensive efforts to decrease the methanol crossover are focused mainly on the development of new polymer electrolyte membranes. In this study, Nafion polymer was modified by means of the incorporation of inorganic oxides with different structural properties (SBA-15 and SiO2), both prepared by sol-gel method in order to increase the proton conductivity at high temperature of fuel cell and to contribute decrementing the methanol crossover effect. Composite membranes based in inorganic fillers showed a significant decrease in the concentration of methanol permeation.

  1. Oxidation of Glycerol and Propanediols in Methanol over Heterogeneous Gold Catalysts

    DEFF Research Database (Denmark)

    Taarning, Esben; Madsen, Anders Theilgaard; Marchetti, Jorge

    2008-01-01

    Aerobic oxidation of glycerol over metal oxide supported gold nanoparticles in methanol results in the formation of dimethyl mesoxalate in selectivities up to 89% at full conversion. The oxidative esterification takes place in methanol, acting both as solvent and reactant, and in the presence...

  2. Crystal structure of di-μ-chlorido-bis[dichloridobis(methanol-κOiridium(III] dihydrate: a surprisingly simple chloridoiridium(III dinuclear complex with methanol ligands

    Directory of Open Access Journals (Sweden)

    Joseph S. Merola

    2015-05-01

    Full Text Available The reaction between IrCl3·xH2O in methanol led to the formation of small amounts of the title compound, [Ir2Cl6(CH3OH4]·2H2O, which consists of two IrCl4O2 octahedra sharing an edge via chloride bridges. The molecule lies across an inversion center. Each octahedron can be envisioned as being comprised of four chloride ligands in the equatorial plane with methanol ligands in the axial positions. A lattice water molecule is strongly hydrogen-bonded to the coordinating methanol ligands and weak interactions with coordinating chloride ligands lead to the formation of a three-dimensional network. This is a surprising structure given that, while many reactions of iridium chloride hydrate are carried out in alcoholic solvents, especially methanol and ethanol, this is the first structure of a chloridoiridium compound with only methanol ligands.

  3. Methanol production method and system

    Science.gov (United States)

    Chen, Michael J.; Rathke, Jerome W.

    1984-01-01

    Ethanol is selectively produced from the reaction of methanol with carbon monoxide and hydrogen in the presence of a transition metal carbonyl catalyst. Methanol serves as a solvent and may be accompanied by a less volatile co-solvent. The solution includes the transition metal carbonyl catalysts and a basic metal salt such as an alkali metal or alkaline earth metal formate, carbonate or bicarbonate. A gas containing a high carbon monoxide to hydrogen ratio, as is present in a typical gasifer product, is contacted with the solution for the preferential production of ethanol with minimal water as a byproduct. Fractionation of the reaction solution provides substantially pure ethanol product and allows return of the catalysts for reuse.

  4. Methanol induces low temperature resilient methanogens and improves methane generation from domestic wastewater at low to moderate temperatures.

    Science.gov (United States)

    Saha, Shaswati; Badhe, Neha; De Vrieze, Jo; Biswas, Rima; Nandy, Tapas

    2015-01-01

    Low temperature (methanol is a preferred substrate by methanogens in cold habitats. The study hypothesizes that methanol can induce the growth of low-temperature resilient, methanol utilizing, hydrogenotrophs in UASB reactor. The hypothesis was tested in field conditions to evaluate the impact of seasonal temperature variations on methane yield in the presence and absence of methanol. Results show that 0.04% (v/v) methanol increased methane up to 15 times and its effect was more pronounced at lower temperatures. The qPCR analysis showed the presence of Methanobacteriales along with Methanosetaceae in large numbers. This indicates methanol induced the growth of both the hydrogenotrophic and acetoclastic groups through direct and indirect routes, respectively. This study thus demonstrated that methanol can impart resistance in methanogenic biomass to low temperature and can improve performance of UASB reactor.

  5. Withanolide artifacts formed in methanol.

    Science.gov (United States)

    Cao, Cong-Mei; Zhang, Huaping; Gallagher, Robert J; Timmermann, Barbara N

    2013-11-22

    Methanol solutions of the main withanolides (6-8) naturally present in Physalis longifolia yielded five artificial withanolides (1-5), including three new compounds (1-3). Withanolides 1 and 2 were identified as intramolecular Michael addition derivatives, while withanolides 3-5 were the result of intermolecular Michael addition. A comprehensive literature investigation was conducted to identify potential withanolide Michael addition artifacts isolated from Solanaceous species to date.

  6. Nanostructured electrocatalytic materials and porous electrodes for direct methanol fuel cells%直接甲醇燃料电池纳米结构电催化材料及多孔电极研究

    Institute of Scientific and Technical Information of China (English)

    王萌; 王新东; 陈明; 杨兆一; 董超振

    2016-01-01

    究进展.重点介绍了纳米结构催化剂和载体材料的合成及表征.  通过对比不同催化材料的特性可以发现,在本文涉及到的催化材料中, In0.1SnO2-Pt和(MoO3)0.2SnO2-Pt/C表现出了最高的催化活性,但是它们高效催化甲醇电氧化所需的碱性环境与现在占绝对主流地位的Nafion质子交换膜所必须的酸性环境相冲突,所以其实际应用价值在碱性阴离子交换膜研究取得突破前都难以有效发挥.而另一类表现较好的采用溶致液晶模板法合成的纳米树枝状和纳米星形Pt催化剂则存在制备工艺难以商业规模化的问题.总的来说,采用溶剂热合成法制备的Pt-NRCeO2/GNs和Pt/Ti0.9Sn0.1O2-C等纳米结构金属氧化物、碳材料复合载体和Pt基贵金属催化剂组成的催化材料体系不仅催化性能相对于商业化Pt纳米颗粒有很大提高,而且制备方法易于商业规模化,值得进一步关注.此外,本文还介绍了如内部传质过程的理论建模计算和膜电极中功能结构的制备等优化DMFC中多孔电极内传质过程的方法.通过计算机模拟得到优化DMFC内部传质过程所需的扩散层、催化层的传质特性相关参数,再通过改进MEA制备工艺,有效控制各层的结构参数向模拟的优化值靠拢,能够实现DMFC性能的有效提升.综合模拟、实验研究及工艺研究结果,根据实际需要,设计和制备包含新功能层的MEA的相关研究也更进一步提高了DMFC的性能和实用性.就目前的研究情况而言,如果在性能提升的基础上,使用寿命再取得突破, DMFC一定会有很好的商业应用前景.%Direct methanol fuel cells (DMFCs) are promising for use in portable devices because of advantages such as high fuel energy density, low working temperature and low emission of pollutants. Nano‐technology has been used to improve the performance of DMFCs. Catalytic materials composed of small

  7. Biofiltration of air contaminated with methanol and toluene

    Directory of Open Access Journals (Sweden)

    Pakamas Chetpattananondh

    2005-12-01

    Full Text Available Biofiltration of air contaminated with VOCs is inexpensive compared with the conventional techniques and very effective for treating large volumes of moist air streams with low concentrations of VOCs. In this study, biofiltration for the purification of polluted air from methanol, a hydrophilic VOC, and toluene, a hydrophobic VOC, was investigated. The experiments were operated using three separated stainless steel biofilters, for methanol, toluene, and a mixture of methanol and toluene, respectively. Biofilter consisted of a mixture of palm shells and activated sludge as a filter-bed material. Only the indigenous microorganisms of the bed medium without any addition of extra inoculum were used throughout the whole process. The polluted air inlet concentration was varied from 0.3-4.7 g/m3 with flow rates ranging from 0.06-0.45 m3/h, equivalent to the empty bed residence times of 9-71 sec. Polluted air was successfully treated by biofiltration, 100% removal efficiencies would be obtained when the air flow rate was lower than 0.45 m3/h. The presence of toluene did not affect the removal rate of methanol while the removal rate of toluene was decreased with the presence of methanol in air stream according to the competition phenomenon.

  8. Antioxidant Activity of Methanolic Extracts from Peanut Skin

    Directory of Open Access Journals (Sweden)

    V. Nepote

    2000-03-01

    Full Text Available Antioxidant activity of skin from runner peanut was performed on sunflower refined oil. The skin was obtained from industrial blanching process. The oil was oxidized at 60ºC. The methanolic extracts show antioxidant activity in relation to the oil (without additives. However these extracts do not reach the activity level from BHT.

  9. The toxicity of inhaled methanol vapors

    Energy Technology Data Exchange (ETDEWEB)

    Kavet, R.; Nauss, K.M. (Environmental Research Information, Inc., Palo Alto, CA (USA))

    1990-01-01

    Methanol could become a major automotive fuel in the U.S., and its use may result in increased exposure of the public to methanol vapor. Nearly all of the available information on methanol toxicity in humans relates to the consequences of acute, rather than chronic, exposures. Acute methanol toxicity evolves in a well-understood pattern and consists of an uncompensated metabolic acidosis with superimposed toxicity to the visual system. The toxic properties of methanol are rooted in the factors that govern both the conversion of methanol to formic acid and the subsequent metabolism of formate to carbon dioxide in the folate pathway. In short, the toxic syndrome sets in if formate generation continues at a rate that exceeds its rate of metabolism. Current evidence indicates that formate accumulation will not challenge the metabolic capacity of the folate pathway at the anticipated levels of exposure to automotive methanol vapor.117 references.

  10. Performance of supercritical methanol in polyurethane degradation

    Directory of Open Access Journals (Sweden)

    Liu Lu

    2016-01-01

    Full Text Available Polyurethane is a group of block copolymer which is composed of diisocyanate, chain extender, and polyol, including polyurethane foam, polyurethane elastomer, waterborne polyurethane, etc. This research focused on thermoplastic polyurethane elastomer (TPU which is formed with 4,4’-diphenylmethane diisocyanate (MDI, poly(1,4-butanediol-hexanedioic acid diolpolyester(PBA and extended with 1,4-butanediol(BDO.The degradation of TPU was carried out with the help of methanol as the supercritical solvent. The SEM of the reaction residues revealed the process of the depolymerisation. The products were measured by GC-MS and found out to be PBA, BDO and 4,4’-methylene diphenyl carbamate(MDC which is themethylate of MDI.GC-FID, HPLC-UV and GPC were used to further analysis. The experimental results showed that supercritical methanol performed outstandingly in TPU recycling, it needed lower temperature and shorter time than regular methods. At 230°C/70min, over 90% raw materials of TPU could be recovered.

  11. Catalysts for the Selective Oxidation of Methanol

    Directory of Open Access Journals (Sweden)

    Catherine Brookes

    2016-06-01

    Full Text Available In industry, one of the main catalysts typically employed for the selective oxidation of methanol to formaldehyde is a multi-component oxide containing both bulk Fe2(MoO43 and excess MoO3. It is thought that the excess MoO3 primarily acts to replace any molybdenum lost through sublimation at elevated temperatures, therefore preventing the formation of an unselective Fe2O3 phase. With both oxide phases present however, debate has arisen regarding the active component of the catalyst. Work here highlights how catalyst surfaces are significantly different from bulk structures, a difference crucial for catalyst performance. Specifically, Mo has been isolated at the surface as the active surface species. This leaves the role of the Fe in the catalyst enigmatic, with many theories postulated for its requirement. It has been suggested that the supporting Fe molybdate phase enables lattice oxygen transfer to the surface, to help prevent the selectivity loss which would occur in the resulting oxygen deficit environment. To assess this phenomenon in further detail, anaerobic reaction with methanol has been adopted to evaluate the performance of the catalyst under reducing conditions.

  12. Better regulation in the European Union : lost in translation or full steam ahead ? : the transposition of EU transport directives across member states

    NARCIS (Netherlands)

    Kaeding, Michael

    2007-01-01

    Better regulation in the European Union cannot be achieved without serious attention to transposition of EU law into national legislation. As a matter of fact, EU member states breach EU law – perpetuately. Why do member states miss deadlines when transposing EU internal market directives? What

  13. Better regulation in the European Union : lost in translation or full steam ahead ? : the transposition of EU transport directives across member states

    NARCIS (Netherlands)

    Kaeding, Michael

    2007-01-01

    Better regulation in the European Union cannot be achieved without serious attention to transposition of EU law into national legislation. As a matter of fact, EU member states breach EU law – perpetuately. Why do member states miss deadlines when transposing EU internal market directives? What fact

  14. Metabolic methanol: molecular pathways and physiological roles.

    Science.gov (United States)

    Dorokhov, Yuri L; Shindyapina, Anastasia V; Sheshukova, Ekaterina V; Komarova, Tatiana V

    2015-04-01

    Methanol has been historically considered an exogenous product that leads only to pathological changes in the human body when consumed. However, in normal, healthy individuals, methanol and its short-lived oxidized product, formaldehyde, are naturally occurring compounds whose functions and origins have received limited attention. There are several sources of human physiological methanol. Fruits, vegetables, and alcoholic beverages are likely the main sources of exogenous methanol in the healthy human body. Metabolic methanol may occur as a result of fermentation by gut bacteria and metabolic processes involving S-adenosyl methionine. Regardless of its source, low levels of methanol in the body are maintained by physiological and metabolic clearance mechanisms. Although human blood contains small amounts of methanol and formaldehyde, the content of these molecules increases sharply after receiving even methanol-free ethanol, indicating an endogenous source of the metabolic methanol present at low levels in the blood regulated by a cluster of genes. Recent studies of the pathogenesis of neurological disorders indicate metabolic formaldehyde as a putative causative agent. The detection of increased formaldehyde content in the blood of both neurological patients and the elderly indicates the important role of genetic and biochemical mechanisms of maintaining low levels of methanol and formaldehyde.

  15. Density Functional Theory Study of Methanol Decomposition on the CeO2(110) Surface

    Energy Technology Data Exchange (ETDEWEB)

    Mei, Donghai [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Deskins, N. Aaron [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dupuis, Michel [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ge, Qingfeng [Southern Illinois Univ., Carbondale, IL (United States)

    2008-02-27

    Methanol decomposition on the stoichiometric CeO2(110) surface has been investigated using density functional theory slab calculations. Three possible initial steps to decompose methanol by breaking one of three bonds (O-H, C-O and C-H) of methanol were examined. The relative order of thermodynamic stability for the three possible bond scission steps is: C-H > O-H > C-O. We further isolated transition state and determined activation energy for each bond-breaking mode using the nudged elastic method. The activation barrier for the most favorable dissociation mode, the O-H bond scission, is 0.3 eV on the (110) surface. An even lower activation barrier (< 0.1 eV) has been obtained on the CeO2(111) surface for the same bond-breaking mode. We aslo calculated the pre-exponential factors based on the harmonic approximation and obtained the overall rate constants at 300 and 500 K for all three initial decomposition steps. In contrast to the order of thermodynamic stability, the calculated bond breaking barriers indicated a different bond breaking order kinetically: O-H > C-O > C-H. Our results are consistent with the previous experimental observation that methoxy is the dominant surface species after a stoichiometric CeO2 surface was exposed to methanol. The experimentally observed methanol chemistry was determined by the kinetics of initial dissociation steps rather than the thermodynamic stability of product states. Surface coverage of methanol was found to affect the relative stability between molecular and dissociative adsorption modes. Dissociative adsorption modes are preferred thermodynamically for methanol coverage up to 0.5 ML but only molecular adsorption was stable at full monolayer coverage. This work was supported by a Laboratory Directed Research and Development (LDRD) project of the Pacific Northwest National Laboratory (PNNL). The computations were performed using the Molecular Science Computing Facility in the William R

  16. Towards a methanol economy based on homogeneous catalysis: methanol to H2 and CO2 to methanol.

    Science.gov (United States)

    Alberico, E; Nielsen, M

    2015-04-21

    The possibility to implement both the exhaustive dehydrogenation of aqueous methanol to hydrogen and CO2 and the reverse reaction, the hydrogenation of CO2 to methanol and water, may pave the way to a methanol based economy as part of a promising renewable energy system. Recently, homogeneous catalytic systems have been reported which are able to promote either one or the other of the two reactions under mild conditions. Here, we review and discuss these developments.

  17. Millimeter/submillimeter Spectroscopy to Measure the Branching Ratios for Methanol Photolysis

    Science.gov (United States)

    McCabe, Morgan N.; Powers, Carson Reed; Zinga, Samuel; Widicus Weaver, Susanna L.

    2016-06-01

    Methanol is one of the most abundant and important molecules in the interstellar medium, playing a key role in driving more complex organic chemistry both on grain surfaces and through gas-phase ion-molecule reactions. Methanol photolysis produces many radicals such as hydroxyl, methoxy, hydroxymethyl, and methyl that may serve as the building blocks for more complex organic chemistry in star-forming regions. The branching ratios for methanol photolysis may govern the relative abundances of many of the more complex species already detected in these environments. However, no direct, comprehensive, quantitative measurement of methanol photolysis branching ratios is available. Using a 193 nm excimer laser, the gas phase photolysis of methanol was studied in the (sub)millimeter range, where the rotational spectroscopic signatures of the photolysis products were probed. Here we present preliminary results from this experiment.

  18. Research Progress on the Indirect Hydrogenation of Carbon Dioxide to Methanol.

    Science.gov (United States)

    Du, Xian-Long; Jiang, Zheng; Su, Dang Sheng; Wang, Jian-Qiang

    2016-02-19

    Methanol is a sustainable source of liquid fuels and one of the most useful organic chemicals. To date, most of the work in this area has focused on the direct hydrogenation of CO2 to methanol. However, this process requires high operating temperatures (200-250 °C), which limits the theoretical yield of methanol. Thus, it is desirable to find a new strategy for the efficient conversion of CO2 to methanol at relatively low reaction temperatures. This Minireview seeks to outline the recent advances on the indirect hydrogenation of CO2 to methanol. Much emphasis is placed on discussing specific systems, including hydrogenation of CO2 derivatives (organic carbonates, carbamates, formates, cyclic carbonates, etc.) and cascade reactions, with the aim of critically highlighting both the achievements and remaining challenges associated with this field.

  19. W4E HYDROPOWER DIRECT DRIVE IN-LINE HYDROTURBINE GENERATOR FULL SCALE PROTOTYPE VALIDATION TESTING REPORT MAY 2013 ALDEN LABORATORIES

    Energy Technology Data Exchange (ETDEWEB)

    Cox, Chad W [GZA GeoEnvironmental,Inc.

    2013-09-24

    The W4E is a patent-pending, direct-drive, variable force turbine/generator. The equipment generates electricity through the water dependent engagement of a ring of rotating magnets with coils mounted on a stator ring. Validation testing of the W4e was performed at Alden Laboratories in the Spring of 2013. The testing was independently observed and validated by GZA GeoEnvironmental, Inc. The observations made during testing and the results of the testing are included in the Test Summary Report

  20. Combining direct imaging and radial velocity data towards a full exploration of the giant planet population. I. Method and first results

    Science.gov (United States)

    Lannier, J.; Lagrange, A. M.; Bonavita, M.; Borgniet, S.; Delorme, P.; Meunier, N.; Desidera, S.; Messina, S.; Chauvin, G.; Keppler, M.

    2017-07-01

    Context. Thanks to the detections of more than 3000 exoplanets these last 20 yr, statistical studies have already highlighted some properties of the distribution of the planet parameters. Nevertheless, few studies have yet investigated the planet populations from short to large separations around the same star since this requires the use of different detection techniques that usually target different types of stars. Aims: We wish to develop a tool that combines direct and indirect methods so as to correctly investigate the giant planet populations at all separations. Methods: We developed the MESS2 code, a Monte Carlo simulation code combining radial velocity and direct imaging data obtained at different epochs for a given star to estimate the detection probability of giant planets spanning a wide range of physical separations. It is based on the generation of synthetic planet populations. Results: We apply MESS2 on a young M1-type, the nearby star AU Mic observed with HARPS and NACO/ESO. We show that giant planet detection limits are significantly improved at intermediate separations (≈20 au in the case of AU Mic). We show that the traditional approach of analyzing the RV and DI detection limits independently systematically overestimates the planet detection limits and hence planet occurrence rates. The use of MESS2 allows us to obtain correct planet occurrence rates in statistical studies, making use of multi-epoch DI data and/or RV measurements. We also show that MESS2 can optimize the schedule of future DI observations.

  1. Experimental Study on Stratified and Homogeneous Combustion of a Methanol Direct-Injection Spark-Ignition Engine%甲醇缸内直喷发动机分层燃烧和均质燃烧的试验研究

    Institute of Scientific and Technical Information of China (English)

    李本正; 刘圣华; 农金吉; 宫艳峰

    2009-01-01

    In a methanol direct-injection spark-ignition (DISI) engine retrofitted from a 4-cylinder diesel engine, the fuel needs to be injected into the cylinder near the end of compression stroke to realize the stratified combustion at partial loads for improving fuel economy. However, at high loads, the fuel needs to be injected into cylinder during intake stroke to realize the homogeneous combustion for achieving high power output. The results show that the methanol DISI engine can operate within the excessive air ratio of 2. 23 and its maximum brake thermal efficiency reaches 35. 3%. The methanol DISI engine exhibits higher power output than that of the original diesel engine. The cyclic variations of imep maintains low under a wide range of operating conditions, which shows a stable combustion. NO_x and soot emissions can be de-creased simultaneously.%在一台4缸柴油机改造的火花点火甲醇缸内直喷发动机上,中低负荷时采用分层燃烧来实现好的燃油经济性,高负荷时采用均质燃烧来获得好的动力性能.试验结果表明,甲醇缸内直喷发动机可以实现过量空气系数为2.23的分层稀薄燃烧;发动机的有效热效率最高可达35.3%,远高于普通汽油机;低速转矩大,动力性超过原机水平;在宽广的转速和负荷范围下平均指示压力的循环变动较小,燃烧稳定性好;该甲醇发动机可以实现NO_x和碳烟的同时降低.

  2. Full-Waveform, Wide-Swath Lidar Imaging of Forested and Urban Areas in Leaf-On Conditions: Development, Results and Future Direction

    Science.gov (United States)

    Blair, James B.; Hofton, M.; Rabine, David; Welch, Wayne; Ramos, Luis; Padden, Phillip

    2003-01-01

    Full-Waveform lidar measurements provide unprecedented views of the vertical and horizontal structure of vegetation and the topography of the Earth s surface. Utilizing a high signal-to-noise ratio lidar system, larger than typical laser footprints (10-20 m), and the recorded time history of interaction between a short-duration (approx. 10 ns) pulse of laser light and the surface of the Earth, full-waveform lidar is able to simultaneously image sub-canopy topography as well as the vertical structure of any overlying vegetation. These data reveal the true 3-D vegetation structure in leaf-on conditions enabling important biophysical parameters such as above-ground biomass to be estimated with unprecedented accuracy. An airborne lidar mission was conducted July-August 2003 in support of the North America Carbon Program. NASA s Laser Vegetation Imaging Sensor (LVIS) was used to image approximately 2,000 km$^2$ in Maine, New Hampshire, Massachusetts and Maryland. Areas with available ground and other data were included (e.g., experimental forests, FLUXNET sites) in order to facilitate as many bio- and geophysical investigations as possible. Data collected included ground elevation and canopy height measurements for each laser footprint, as well as the vertical distribution of intercepted surfaces. Data will be publicly distributed within 6- 12 months of collection. Further details of the mission, including the lidar system technology, the locations of the mapped areas, and examples of the numerous data products that can be derived from the return waveform data products will be presented. Future applications including detection of ground and vegetation canopy changes and a spaceborne implementation of wide-swath, full-waveform imaging lidar will also be discussed.

  3. Application of Flexible Micro Temperature Sensor in Oxidative Steam Reforming by a Methanol Micro Reformer

    Directory of Open Access Journals (Sweden)

    Yi-Man Lo

    2011-02-01

    Full Text Available Advances in fuel cell applications reflect the ability of reformers to produce hydrogen. This work presents a flexible micro temperature sensor that is fabricated based on micro-electro-mechanical systems (MEMS technology and integrated into a flat micro methanol reformer to observe the conditions inside that reformer. The micro temperature sensor has higher accuracy and sensitivity than a conventionally adopted thermocouple. Despite various micro temperature sensor applications, integrated micro reformers are still relatively new. This work proposes a novel method for integrating micro methanol reformers and micro temperature sensors, subsequently increasing the methanol conversion rate and the hydrogen production rate by varying the fuel supply rate and the water/methanol ratio. Importantly, the proposed micro temperature sensor adequately controls the interior temperature during oxidative steam reforming of methanol (OSRM, with the relevant parameters optimized as well.

  4. In vitro antioxidant, antifungal and cytotoxic activity of methanolic extract of Calligonum polygonoides

    Directory of Open Access Journals (Sweden)

    Arif Khan

    2015-06-01

    Full Text Available Present study is aimed at the pharmacological characterization of methanol extract of Calligonum polygonoides from District Bannu. Dried plant was grounded and extracted with methanol to prepare methanol crud extract. In vitro biological assays were conducted using this methanolic extract according to standard protocol. Cytotoxic activity of plant methanolic extract against brine shrimps while antifungal activity was also measured. Eighty percent death rate of brine shrimp was observed at 1,000 μg/mL of plant extract. 70 ± 0.0% growth inhibition of Aspergillus niger was measured during the present study. Significant scavenging results were observed during scavenging of free radicles viz; 78.1% against DPPH, 83.1% to ABTS and 36% against superoxide at 500 μg/mL were obtained. The results obtained in this study indicate that C. polygonoides possess significant antioxidant, antifungal and cytotoxic bioactive compounds.

  5. CATALYTIC CONVERSION OF FORMIC ACID TO METHANOL WITH Cu AND Al UNDER HYDROTHERMAL CONDITIONS

    Directory of Open Access Journals (Sweden)

    Hansong Yao,

    2012-01-01

    Full Text Available Catalytic conversion of formic acid into methanol was investigated with Cu as a catalyst and Al as a reductant under hydrothermal conditions. It was found that formic acid can be converted into methanol by such means. The highest yield of methanol (30.4% was attained with a temperature of 300 °C and a reaction time of 9 h. The AlO(OH formed from Al oxidation may also play a catalytic role in the formation of methanol. This process may provide a promising solution to producing methanol from carbohydrate biomass combined with the process of converting the carbohydrate into formic acid, which is expected to emit no CO2.

  6. Full-Scale Fatigue Testing of a Wind Turbine Blade in Flapwise Direction and Examining the Effect of Crack Propagation on the Blade Performance.

    Science.gov (United States)

    Al-Khudairi, Othman; Hadavinia, Homayoun; Little, Christian; Gillmore, Gavin; Greaves, Peter; Dyer, Kirsten

    2017-10-03

    In this paper, the sensitivity of the structural integrity of wind turbine blades to debonding of the shear web from the spar cap was investigated. In this regard, modal analysis, static and fatigue testing were performed on a 45.7 m blade for three states of the blade: (i) as received blade (ii) when a crack of 200 mm was introduced between the web and the spar cap and (iii) when the crack was extended to 1000 mm. Calibration pull-tests for all three states of the blade were performed to obtain the strain-bending moment relationship of the blade according to the estimated target bending moment (BM) which the blade is expected to experience in its service life. The resultant data was used to apply appropriate load in the fatigue tests. The blade natural frequencies in flapwise and edgewise directions over a range of frequency domain were found by modal testing for all three states of the blade. The blade first natural frequency for each state was used for the flapwise fatigue tests. These were performed in accordance with technical specification IEC TS 61400-23. The fatigue results showed that, for a 200 mm crack between the web and spar cap at 9 m from the blade root, the crack did not propagate at 50% of the target BM up to 62,110 cycles. However, when the load was increased to 70% of target BM, some damages were detected on the pressure side of the blade. When the 200 mm crack was extended to 1000 mm, the crack began to propagate when the applied load exceeded 100% of target BM and the blade experienced delaminations, adhesive joint failure, compression failure and sandwich core failure.

  7. Antianxiety Activity of Methanol Extract of Gelsemium sempervirens (Linn. Ait.

    Directory of Open Access Journals (Sweden)

    Garg Vandana

    2012-05-01

    Full Text Available Background: Despite significant advances in understanding and management of neuropsychiatric disorders during past few decades, anxiety and depression, still remains the leading cause of deaths, primarily for want of effective and safe treatment of these ailments. Approximately, two third of the anxious or depressed patients respond to the currently available treatment but the magnitude of improvement is still disappointingPurpose of Study: The aim of the present study was to investigate the antianxiety activity of Gelsemium sempervirens (Linn. Ait. Various doses (50,100, 150, 200mg/kg of plant extracts viz., of petroleum ether, chloroform, methanol and water were administered orally to Swiss Albino Mice before evaluating their behavioural pattern. Diazepam (2.5 mg/kg was used as standard drug.Result: The methanol extract of G. sempervirens (150 mg/kg increased the mean time spent, mean number of arms entries in the open arms of elevated plus maze (EPM and decreased the mean time spent in the closed arms. The locomotor activity of methanol extract was not affected to the same extent as observed for diazepam.Conclusion: The results suggested that methanol extract of G. sempervirens possess anxiolytic effects with no sedative activity when compared to diazepam.

  8. Integrating the Carbon and Water Footprints’ Costs in the Water Framework Directive 2000/60/EC Full Water Cost Recovery Concept: Basic Principles Towards Their Reliable Calculation and Socially Just Allocation

    OpenAIRE

    Anastasia Papadopoulou; Stavroula Tsitsifli; Vasilis Kanakoudis

    2012-01-01

    This paper presents the basic principles for the integration of the water and carbon footprints cost into the resource and environmental costs respectively, taking the suggestions set by the Water Framework Directive (WFD) 2000/60/EC one step forward. WFD states that full water cost recovery (FWCR) should be based on the estimation of the three sub-costs related: direct; environmental; and resource cost. It also strongly suggests the EU Member States develop and apply effective water pricing ...

  9. Developmental and Reproductive Toxicology of Methanol

    Science.gov (United States)

    Methanol is a high production volume chemical used as a feedstock for chemical syntheses and as a solvent and fuel additive. Methanol is acutely toxic to humans, causing acidosis, blindness in death at high dosages, but its developmental and reproductive toxicity in humans is poo...

  10. Hydrogenation of carbon dioxide for methanol production

    NARCIS (Netherlands)

    Ham, van der A.G.J.; Berg, van den H.; Benneker, A.; Simmelink, G.; Timmer, J.; Weerden, van S.

    2012-01-01

    A process for the hydrogenation of CO2 to methanol with a capacity of 10 kt/y methanol is designed in a systematic way. The challenge will be to obtain a process with a high net CO2 conversion. From initially four conceptual designs the most feasible is selected and designed in more detail. The feed

  11. Catalytic conversion of methane to methanol on Cu-SSZ-13 using N2O as oxidant.

    Science.gov (United States)

    Ipek, B; Lobo, R F

    2016-11-08

    Direct catalytic methanol production from methane is achieved on Cu-SSZ-13 zeolite catalysts using N2O as the oxidant. The methanol production rate on Cu-SSZ-13 (on a per gram basis) was more than twice the rate on Cu-mordenite and more than four times the rate on Cu-ZSM-5.

  12. A search for extragalactic methanol masers

    CERN Document Server

    Ellingsen, S P; Whiteoak, J B; Vaile, R A; McCulloch, P M; Price, M

    1994-01-01

    A sensitive search for 6.7--GHz methanol maser emission has been made towards 10 galaxies that have yielded detectable microwave molecular--line transitions. These include several which show OH megamaser or superluminous \\water\\/ maser emission. Within the Galaxy, \\methanol\\/ and OH masers often occur in the same star formation regions and, in most cases, the \\methanol\\/ masers have a greater peak flux density than their OH counterparts. Thus we might expect \\methanol\\/ masers to be associated with extragalactic OH maser sources. We failed to detect any emission or absorption above our 60--mJy detection limit. We conclude that if the physical conditions exist to produce \\methanol\\/ megamaser emission, they are incompatible with the conditions which produce OH megamaser emission.

  13. Production of methanol/DME from biomass

    DEFF Research Database (Denmark)

    Ahrenfeldt, Jesper; Henriksen, Ulrik Birk; Münster-Swendsen, Janus

    In this project the production of DME/methanol from biomass has been investigated. Production of DME/methanol from biomass requires the use of a gasifier to transform the solid fuel to a synthesis gas (syngas) - this syngas can then be catalytically converted to DME/methanol. Two different gasifier...... cleaning. This was proved by experiments. Thermodynamic computer models of DME and methanol plants based on using the Two-Stage Gasification concept were created to show the potential of such plants. The models showed that the potential biomass to DME/methanol + net electricity energy efficiency was 51...... gasification, but little information exists on using these types of gasifiers for biomass gasification. The experiments performed provided quantitative data on product and gas composition as a function of operation conditions. Biomass can be gasified with less oxygen consumption compared to coal. The organic...

  14. Synthesis of PtNi Alloy Nanoparticles on Graphene-Based Polymer Nanohybrids for Electrocatalytic Oxidation of Methanol

    Directory of Open Access Journals (Sweden)

    Tung-Yuan Yung

    2016-12-01

    Full Text Available We have successfully produced bimetallic PtNi alloy nanoparticles on poly(diallyldimethylammonium chloride (PDDA-modified graphene nanosheets (PtNi/PDDA-G by the “one-pot” hydrothermal method. The size of PtNi alloy nanoparticles is approximately 2–5 nm. The PDDA-modified graphene nanosheets (PDDA-G provides an anchored site for metal precursors; hence, the PtNi nanoparticles could be easily bond on the PDDA-G substrate. PtNi alloy nanoparticles (2–5 nm display a homogenous alloy phase embedded on the PDDA-G substrate, evaluated by Raman, X-ray diffractometer (XRD, thermal gravity analysis (TGA, electron surface chemical analysis (ESCA, and electron energy loss spectroscopy (EELS. The Pt/Ni ratio of PtNi alloy nanoparticles is ~1.7, examined by the energy dispersive spectroscopy (EDS spectra of transmitting electron microscopy (EDS/TEM spectra and mapping technique. The methanol electro-oxidation of PtNi/PDDA-G was evaluated by cyclic voltammetry (CV in 0.5 M of H2SO4 and 0.5 M of CH3OH. Compared to Pt on carbon nanoparticles (Pt/C and Pt on Graphene (Pt/G, the PtNi/PDDA-G exhibits the optimal electrochemical surface area (ECSA, methanol oxidation reaction (MOR activity, and durability by chrono amperometry (CA test, which can be a candidate for MOR in the electro-catalysis of direct methanol fuel cells (DMFC.

  15. Acidotolerant Bacteria and Fungi as a Sink of Methanol-Derived Carbon in a Deciduous Forest Soil

    Directory of Open Access Journals (Sweden)

    Mareen Morawe

    2017-07-01

    Full Text Available Methanol is an abundant atmospheric volatile organic compound that is released from both living and decaying plant material. In forest and other aerated soils, methanol can be consumed by methanol-utilizing microorganisms that constitute a known terrestrial sink. However, the environmental factors that drive the biodiversity of such methanol-utilizers have been hardly resolved. Soil-derived isolates of methanol-utilizers can also often assimilate multicarbon compounds as alternative substrates. Here, we conducted a comparative DNA stable isotope probing experiment under methylotrophic (only [13C1]-methanol was supplemented and combined substrate conditions ([12C1]-methanol and alternative multi-carbon [13Cu]-substrates were simultaneously supplemented to (i identify methanol-utilizing microorganisms of a deciduous forest soil (European beech dominated temperate forest in Germany, (ii assess their substrate range in the soil environment, and (iii evaluate their trophic links to other soil microorganisms. The applied multi-carbon substrates represented typical intermediates of organic matter degradation, such as acetate, plant-derived sugars (xylose and glucose, and a lignin-derived aromatic compound (vanillic acid. An experimentally induced pH shift was associated with substantial changes of the diversity of active methanol-utilizers suggesting that soil pH was a niche-defining factor of these microorganisms. The main bacterial methanol-utilizers were members of the Beijerinckiaceae (Bacteria that played a central role in a detected methanol-based food web. A clear preference for methanol or multi-carbon substrates as carbon source of different Beijerinckiaceae-affiliated phylotypes was observed suggesting a restricted substrate range of the methylotrophic representatives. Apart from Bacteria, we also identified the yeasts Cryptococcus and Trichosporon as methanol-derived carbon-utilizing fungi suggesting that further research is needed to

  16. Biodiesel II: A new concept of biodiesel production - transesterification with supercritical methanol

    Directory of Open Access Journals (Sweden)

    Skala Dejan U.

    2004-01-01

    Full Text Available Biodiesel is defined as a fuel that might be used as a pure biofuel or at high concentration in mineral oil derivatives, in accordance with specific quality standards for transport applications. The main raw material used for biodiesel production is rapeseed, which contains mono-unsaturated (about 60% and also, in a lower quantity, poly-unsaturated fatty acids (C 18:1 and C 18:3, as well as some amounts of undesired saturated fatty acids (palmitic and stearic acids. Other raw materials have also been used in the research and industrial production of biodiesel (palm-oil, sunflower-oil, soybean-oil, waste plant oil, animal fats, etc. The historical background of the biodiesel production, installed industrial capacities, as well as Directives of the European Parliament and of the Council (May 2003 regarding the promotion of the use of biofuels or other renewable fuels for transport are discussed in the first part of this article (Chem. Ind. 58 (2004. The second part focused on some new concepts and the future development of technology for biodiesel production based on the use of non-catalytic transesterification under supercritical conditions. A literature review, as well as original results based on the transesterification of animal fats, plant oil and used plant oil were discussed. Obtained results were compared with the traditional concept of transesterification based on base or acid catalysis. Experimental investigations of transesterification with supercritical methanol were performed in a 2 dm3 autoclave at 140 bar pressure and at 300°C with molar ratio of methanol to triglycerides of about 41. The degree of esterification strongly depends on the density of supercritical methanol and on the possibility of reaction occurring in one phase.

  17. Methyl 6-O-trityl-α-d-glucopyranoside methanol disolvate

    Directory of Open Access Journals (Sweden)

    Zeynep Gültekin

    2014-04-01

    Full Text Available The asymmetric unit of the title compound, C26H28O6·2CH3OH, contains two independent methyl 6-O-trityl-α-d-glucopyranoside molecules and four methanol solvent molecules. The rings of two methyl α-d-glucopyranoside adopt chair conformations. In the crystal, extensive intra- and intermolecular O—H...O and C—H...O hydrogen bonds link the molecules into a three-dimensional supramolecular architecture.

  18. Secondary Metabolites Analysis of Methanol Extract of Surian (Toona sureni (Bl. Merr Leaf as Antioxidant Potential.

    Directory of Open Access Journals (Sweden)

    Yuhernita

    2011-04-01

    Full Text Available Secondary Metabolites Analysis of Methanol Extract of Surian (Toona sureni (Bl. Merr Leaf as AntioxidantPotential. The study of performed secondary metabolites from the methanol extract of Surian (Toona sureni (Bl. Merrleaves have been done by thin-layer chromatography (TLC method. The result showed that methanol extract of Surianleaves consist of alkaloid, flavonoid, polyphenol and terpenoid. All of them positively have the ability to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH. It has IC50 (4.80 are smaller than the ascorbat acid standard (IC50 = 9.23.

  19. EVALUATION OF ANTIBACTERIAL ACTIVITY OF METHANOLIC EXTRACT OF SEEDS OF PHYLA NODIFLORA LINN.

    Directory of Open Access Journals (Sweden)

    Patel Janki B

    2011-06-01

    Full Text Available ‘Jalapippali’ described in classical texts of Ayurveda is botanically identified as Phyla nodiflora Linn. (Syn. Lippia nodiflora Rich. In present study methanolic extract of seeds of Phyla nodiflora Linn. was screened for in-vitro antibacterial activity against gram positive and gram negative bacteria by cup- plate method. The methanolic extract of the seeds significantly inhibit the growth of bacteria as compared to the standard bactericide (streptomycin. The study reveals that the methanolic fraction of seeds of Phyla nodiflora Linn possesses significant antibacterial activity.

  20. A validated near-infrared spectroscopic method for methanol detection in biodiesel

    Science.gov (United States)

    Paul, Andrea; Bräuer, Bastian; Nieuwenkamp, Gerard; Ent, Hugo; Bremser, Wolfram

    2016-06-01

    Biodiesel quality control is a relevant issue as biodiesel properties influence diesel engine performance and integrity. Within the European metrology research program (EMRP) ENG09 project ‘Metrology for Biofuels’, an on-line/at-site suitable near-infrared spectroscopy (NIRS) method has been developed in parallel with an improved EN14110 headspace gas chromatography (GC) analysis method for methanol in biodiesel. Both methods have been optimized for a methanol content of 0.2 mass% as this represents the maximum limit of methanol content in FAME according to EN 14214:2009. The NIRS method is based on a mobile NIR spectrometer equipped with a fiber-optic coupled probe. Due to the high volatility of methanol, a tailored air-tight adaptor was constructed to prevent methanol evaporation during measurement. The methanol content of biodiesel was determined from evaluation of NIRS spectra by partial least squares regression (PLS). Both GC analysis and NIRS exhibited a significant dependence on biodiesel feedstock. The NIRS method is applicable to a content range of 0.1% (m/m) to 0.4% (m/m) of methanol with uncertainties at around 6% relative for the different feedstocks. A direct comparison of headspace GC and NIRS for samples of FAMEs yielded that the results of both methods are fully compatible within their stated uncertainties.

  1. Size-restricted proton transfer within toluene-methanol cluster ions.

    Science.gov (United States)

    Chiang, Chi-Tung; Shores, Kevin S; Freindorf, Marek; Furlani, Thomas; DeLeon, Robert L; Garvey, James F

    2008-11-20

    To understand the interaction between toluene and methanol, the chemical reactivity of [(C6H5CH3)(CH3OH) n=1-7](+) cluster ions has been investigated via tandem quadrupole mass spectrometry and through calculations. Collision Induced Dissociation (CID) experiments show that the dissociated intracluster proton transfer reaction from the toluene cation to methanol clusters, forming protonated methanol clusters, only occurs for n = 2-4. For n = 5-7, CID spectra reveal that these larger clusters have to sequentially lose methanol monomers until they reach n = 4 to initiate the deprotonation of the toluene cation. Metastable decay data indicate that for n = 3 and n = 4 (CH3OH)3H(+) is the preferred fragment ion. The calculational results reveal that both the gross proton affinity of the methanol subcluster and the structure of the cluster itself play an important role in driving this proton transfer reaction. When n = 3, the cooperative effect of the methanols in the subcluster provides the most important contribution to allow the intracluster proton transfer reaction to occur with little or no energy barrier. As n >or= 4, the methanol subcluster is able to form ring structures to stabilize the cluster structures so that direct proton transfer is not a favored process. The preferred reaction product, the (CH3OH)3H(+) cluster ion, indicates that this size-restricted reaction is driven by both the proton affinity and the enhanced stability of the resulting product.

  2. Engineering Escherichia coli for methanol conversion.

    Science.gov (United States)

    Müller, Jonas E N; Meyer, Fabian; Litsanov, Boris; Kiefer, Patrick; Potthoff, Eva; Heux, Stéphanie; Quax, Wim J; Wendisch, Volker F; Brautaset, Trygve; Portais, Jean-Charles; Vorholt, Julia A

    2015-03-01

    Methylotrophic bacteria utilize methanol and other reduced one-carbon compounds as their sole source of carbon and energy. For this purpose, these bacteria evolved a number of specialized enzymes and pathways. Here, we used a synthetic biology approach to select and introduce a set of "methylotrophy genes" into Escherichia coli based on in silico considerations and flux balance analysis to enable methanol dissimilation and assimilation. We determined that the most promising approach allowing the utilization of methanol was the implementation of NAD-dependent methanol dehydrogenase and the establishment of the ribulose monophosphate cycle by expressing the genes for hexulose-6-phosphate synthase (Hps) and 6-phospho-3-hexuloisomerase (Phi). To test for the best-performing enzymes in the heterologous host, a number of enzyme candidates from different donor organisms were selected and systematically analyzed for their in vitro and in vivo activities in E. coli. Among these, Mdh2, Hps and Phi originating from Bacillus methanolicus were found to be the most effective. Labeling experiments using (13)C methanol with E. coli producing these enzymes showed up to 40% incorporation of methanol into central metabolites. The presence of the endogenous glutathione-dependent formaldehyde oxidation pathway of E. coli did not adversely affect the methanol conversion rate. Taken together, the results of this study represent a major advancement towards establishing synthetic methylotrophs by gene transfer.

  3. Impregnated membranes for direct methanol fuel cells at high methanol concentrations

    NARCIS (Netherlands)

    Yildirim, M. Hakan; Schwarz, Alexander; Stamatialis, Dimitrios F.; Wessling, Matthias

    2009-01-01

    Sulfonated poly(phthalazinone ether ketone) (SPPEK) impregnated Solupor® microporous film (SPPEK–PE) and pure SPPEK membranes with two different ion-exchange capacities (IECs) were prepared and characterized for use in DMFC applications. Swelling, proton conductivity, diffusion and DMFC experiments

  4. Direct Synthesis of Dimethyl Ether in Microstructured Reactors: The Interactions Between Methanol Synthesis and Methanol Dehydration

    OpenAIRE

    Dadgar, Farbod

    2016-01-01

    The growing concerns about the climate change, energy security and the diminishing oil reserves, stimulate the search for alternative energy sources and non-petroleum-based fuels. Natural gas in the short-term, and biomass in the long-term, have the potential to satisfy an increasing portion of the energy demands and reduce the dependence on carbon-intensive coal and oil. However, exploitation of highly distributed biomass resources and a considerable amount of the natural gas ...

  5. Impregnated membranes for direct methanol fuel cells at high methanol concentrations

    NARCIS (Netherlands)

    Yildirim, M.H.; Schwarz, Alexander; Stamatialis, Dimitrios; Wessling, Matthias

    2009-01-01

    Sulfonated poly(phthalazinone ether ketone) (SPPEK) impregnated Solupor® microporous film (SPPEK–PE) and pure SPPEK membranes with two different ion-exchange capacities (IECs) were prepared and characterized for use in DMFC applications. Swelling, proton conductivity, diffusion and DMFC experiments

  6. Sorption phenomena of methanol on heat treated coal; Netsushori wo hodokoshita sekitan no methanol kyuchaku tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, H.; Kaiho, M.; Yamada, O.; Soneda, Y.; Kobayashi, M.; Makino, M. [National Institute for Resources and Environment, Tsukuba (Japan)

    1996-10-28

    Experiments were carried out to learn methanol sorption characteristics of heat-treated coal. When Taiheiyo coal is heat-treated at 125{degree}C, performed with a first methanol adsorption at 25{degree}C, and then desorption at 25{degree}C, a site with strong interaction with methanol and a site with relatively weak interaction are generated in test samples. A small amount of methanol remains in both sites. Then, when the methanol is desorbed at as low temperature as 70{degree}C, the methanol in the site with strong interaction remains as it has existed therein, but the methanol in the site with relatively weak interaction desorbs partially, hence the adsorption amount in a second adsorption at 25{degree}C increases. However, when desorption is performed at as high temperature as 125{degree}C, the methanol in the site with strong interaction also desorbs, resulting in increased adsorption heat in the second adsorption. The adsorption velocity drops, however. Existence of methanol in a site with strong interaction affects the adsorption velocity, but no effect is given by methanol in a site with weak interaction. 3 refs., 4 figs.

  7. Hydrogen Production from Methanol Using Corona Discharges

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Hydrogen production at room temperature from liquid methanol has been conductedusing corona discharge. The content of water in methanol solution has a significant effect on thisproduction. When water concentration increases from 1.0 % to 16.7 %, the methanol conversionrate changes from 0.196 to 0.284 mol/h. An important finding in this investigation is theformation of ethylene glycol as a major by-product. The yield of ethylene glycol is ranged from0.0045 to 0.0075 mol/h based on the water content.

  8. Catalytic Conversion of Methanol by Oxidative Dehydrogenation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This study investigates the effects of addition of oxygen on the oxidative dehydrogenation (ODH) of methanol when a fluorotetrasilicic mica ion-exchanged with palladium (Pd2+-TSM) was used as the catalyst. The reaction proceeded at a very low temperature in the presence of oxygen, and HCOOCH3 was obtained at high selectivity. By calculating the equilibrium conversion, it has been shown that substantial ODH took place for HCOOCH3 production. Consequently, this reaction would make dehydrogenation the dominant reaction at equilibrium. Not all the H dissociated from CH3OH was converted to H2O by oxidation. It has been shown that the H2O was not produced from oxidative dehydrogenation by the direct reaction of CH3OH and O2 when an attempt was made to carry out oxidative dehydrogenation using an isotope oxygen trace method in the gas phase. Therefore, when CH3OH was converted to CO2 and dehydrogenated to HCOOCH3, the C-O bonds were not dissociated.

  9. Tropospheric methanol observations from space: constraints on the seasonality of biogenic emissions

    Science.gov (United States)

    Wells, K. C.; Millet, D. B.; Cady-Pereira, K. E.; Shephard, M. W.; Xiao, Y.; Razavi, A.; Clerbaux, C.

    2011-12-01

    Methanol is the most abundant non-methane organic compound in the atmosphere, and is an important precursor of atmospheric pollutants such as CO and formaldehyde. The recent development of methanol retrievals from nadir-viewing satellite-based platforms offers powerful new information for quantifying methanol emissions on a global scale. This study uses methanol observations from the Tropospheric Emission Spectrometer (TES) on the Aura satellite and the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp-A satellite, in conjunction with aircraft data, to investigate methanol emissions from major plant functional types in the GEOS-Chem global chemical transport model (driven with MEGAN biogenic emissions). We first evaluate the TES methanol retrievals by comparing to simulation results and flight observations from several North American field campaigns. Results show that the retrieval performs well when the degrees of freedom for signal are above 0.5. We analyze one full year of TES and IASI observations and find a persistent model underestimate in springtime, and make recommendations for an improved seasonal distribution of biogenic methanol emissions over temperate regions of the globe.

  10. Structural insights into methanol-stable variants of lipase T6 from Geobacillus stearothermophilus.

    Science.gov (United States)

    Dror, Adi; Kanteev, Margarita; Kagan, Irit; Gihaz, Shalev; Shahar, Anat; Fishman, Ayelet

    2015-11-01

    Enzymatic production of biodiesel by transesterification of triglycerides and alcohol, catalyzed by lipases, offers an environmentally friendly and efficient alternative to the chemically catalyzed process while using low-grade feedstocks. Methanol is utilized frequently as the alcohol in the reaction due to its reactivity and low cost. However, one of the major drawbacks of the enzymatic system is the presence of high methanol concentrations which leads to methanol-induced unfolding and inactivation of the biocatalyst. Therefore, a methanol-stable lipase is of great interest for the biodiesel industry. In this study, protein engineering was applied to substitute charged surface residues with hydrophobic ones to enhance the stability in methanol of a lipase from Geobacillus stearothermophilus T6. We identified a methanol-stable variant, R374W, and combined it with a variant found previously, H86Y/A269T. The triple mutant, H86Y/A269T/R374W, had a half-life value at 70 % methanol of 324 min which reflects an 87-fold enhanced stability compared to the wild type together with elevated thermostability in buffer and in 50 % methanol. This variant also exhibited an improved biodiesel yield from waste chicken oil compared to commercial Lipolase 100L® and Novozyme® CALB. Crystal structures of the wild type and the methanol-stable variants provided insights regarding structure-stability correlations. The most prominent features were the extensive formation of new hydrogen bonds between surface residues directly or mediated by structural water molecules and the stabilization of Zn and Ca binding sites. Mutation sites were also characterized by lower B-factor values calculated from the X-ray structures indicating improved rigidity.

  11. Characterization and evolution of an activator-independent methanol dehydrogenase from Cupriavidus necator N-1.

    Science.gov (United States)

    Wu, Tung-Yun; Chen, Chang-Ting; Liu, Jessica Tse-Jin; Bogorad, Igor W; Damoiseaux, Robert; Liao, James C

    2016-06-01

    Methanol utilization by methylotrophic or non-methylotrophic organisms is the first step toward methanol bioconversion to higher carbon-chain chemicals. Methanol oxidation using NAD-dependent methanol dehydrogenase (Mdh) is of particular interest because it uses NAD(+) as the electron carrier. To our knowledge, only a limited number of NAD-dependent Mdhs have been reported. The most studied is the Bacillus methanolicus Mdh, which exhibits low enzyme specificity to methanol and is dependent on an endogenous activator protein (ACT). In this work, we characterized and engineered a group III NAD-dependent alcohol dehydrogenase (Mdh2) from Cupriavidus necator N-1 (previously designated as Ralstonia eutropha). This enzyme is the first NAD-dependent Mdh characterized from a Gram-negative, mesophilic, non-methylotrophic organism with a significant activity towards methanol. Interestingly, unlike previously reported Mdhs, Mdh2 does not require activation by known activators such as B. methanolicus ACT and Escherichia coli Nudix hydrolase NudF, or putative native C. necator activators in the Nudix family under mesophilic conditions. This enzyme exhibited higher or comparable activity and affinity toward methanol relative to the B. methanolicus Mdh with or without ACT in a wide range of temperatures. Furthermore, using directed molecular evolution, we engineered a variant (CT4-1) of Mdh2 that showed a 6-fold higher K cat/K m for methanol and 10-fold lower K cat/K m for n-butanol. Thus, CT4-1 represents an NAD-dependent Mdh with much improved catalytic efficiency and specificity toward methanol compared with the existing NAD-dependent Mdhs with or without ACT activation.

  12. Autoprotolysis in water/methanol/NaCl ternary systems

    Directory of Open Access Journals (Sweden)

    Farajtabar Ali

    2013-01-01

    Full Text Available A potentiometric method was used to determine the autoprotolysis constant for aqueous solutions containing 0, 20 and 40 weight percent of methanol in wide range of NaCl concentration at 25°C. Ionic strength was ranged between 0.25 and 2.00 mol L-1 by intervals of 0.25 units. Osmotic and activity coefficient of mixed solvents were calculated as a function of ionic strength. Dependence on ionic strength was analyzed by using the original Specific ion Interaction Theory. The specific ion interaction parameters were extracted associated with the thermodynamic autoprotolysis constant. Results indicate that interaction between ions increases with the increasing of the methanol content in mixture.

  13. 2-(2-Carboxyethyl-1,3-dioxoisoindoline-5,6-dicarboxylic acid methanol monosolvate

    Directory of Open Access Journals (Sweden)

    Sanaz Khorasani

    2012-01-01

    Full Text Available In the title compound, C13H9NO8·CH3OH, the main molecule possesses three carboxylic acid groups, which are asymmetrically distributed around the molecule core. This results in hydrogen-bonding motifs ranging from a chain to various rings. The combination of the chain motif together with a carboxylic dimer R22(8 ring motif creates a ribbon of molecules propagating along the c-axis direction. A second ribbon results from the combination of the chain motif together with a methanol solvent molecule and carboxyl-containing R44(12 ring motif. These two ribbons combine alternately, forming a hydrogen-bonded layer of molecules parallel to (2overline{1}0.

  14. Methanol production from fermentor off-gases

    Science.gov (United States)

    Dale, B. E.; Moreira, A. R.

    The off gases from an acetone butanol fermentation facility are composed mainly of CO2 and H2. Such a gas stream is an ideal candidate as a feed to a methanol synthesis plant utilizing modern technology recently developed and known as the CDH-methanol process. A detailed economic analysis for the incremental cost of a methanol synthesis plant utilizing the off gases from an acetone butanol fermentation indicates a profitable rate of return of 25 to 30% under the most likely production conditions. Bench scale studies at different fermentor mixing rates indicate that the volume of gases released during the fermentation is a strong function of the agitation rate and point to a potential interaction between the volume of H2 evolved and the levels of butanol present in the final fermented broth. Such interaction may require establishing optimum operating conditions for an integrated butanol fermentation methanol synthesis plant.

  15. Methanol: A Versatile Fuel for Immediate Use

    Science.gov (United States)

    Reed, T. B.; Lerner, R. M.

    1973-01-01

    Advocates the large-scale production and use of methanol as a substitute for the diminishing reserves of low-cost petroleum resources. Describes the manufacturing process and advantages of the versatile fuel. (JR)

  16. Quiet Changes in the Methanol Supply Mode

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ The coal chemicals sector, the new coal chemicals sector in particular, has been emerging fast in China in recent years. The production scale of methanol as an important coal chemical product has expanded constantly.

  17. Cancer chemopreventive property of Bidens pilosa methanolic ...

    African Journals Online (AJOL)

    admin

    Cancer chemopreventive property of Bidens pilosa methanolic extract on two stage in vivo skin carcinogenesis ... In the forestomach, kidney and lung, glutathione S-transferase and ..... weight gain profile or terminal in mice treated with the two ...

  18. Methanol and ethanol modulate responses to danger- and microbe-associated molecular patterns

    Directory of Open Access Journals (Sweden)

    Claire T Hann

    2014-10-01

    Full Text Available Methanol is a byproduct of cell wall modification, released through the action of pectin methylesterases (PMEs, which demethylesterify cell wall pectins. Plant PMEs play not only a role in developmental processes but also in responses to herbivory and infection by fungal or bacterial pathogens. Molecular mechanisms that explain how methanol affects plant defenses are poorly understood. Here we show that exogenously supplied methanol alone has weak effects on defense signaling in three dicot species, however it profoundly alters signaling responses to danger- and microbe-associated molecular patterns (DAMPs, MAMPs such as the alarm hormone systemin, the bacterial flagellum-derived flg22 peptide, and the fungal cell wall-derived oligosaccharide chitosan. In the presence of methanol the kinetics and amplitudes of DAMP/MAMP-induced MAP kinase (MAPK activity and oxidative burst are altered in tobacco and tomato suspension-cultured cells, in Arabidopsis seedlings and tomato leaf tissue. As a possible consequence of altered DAMP/MAMP signaling, methanol suppressed the expression of the defense genes PR-1 and PI-1 in tomato. In cell cultures of the grass tall fescue (Festuca arundinacea, Poaceae, Monocots, methanol alone activates MAPKs and increases chitosan-induced MAPK activity, and in the darnel grass Lolium temulentum (Poaceae, it alters wound-induced MAPK signaling. We propose that methanol can be recognized by plants as a sign of the damaged self. In dicots, methanol functions as a DAMP-like alarm signal with little elicitor activity on its own, whereas it appears to function as an elicitor-active DAMP in monocot grasses. Ethanol had been implicated in plant stress responses, although the source of ethanol in plants is not well established. We found that it has a similar effect as methanol on responses to MAMPs and DAMPs.

  19. Sources and seasonality of atmospheric methanol based on tall tower measurements in the US Upper Midwest

    Directory of Open Access Journals (Sweden)

    L. Hu

    2011-06-01

    Full Text Available We present over one year of continuous atmospheric methanol measurements from the University of Minnesota tall tower Trace Gas Observatory (KCMP tall tower; 244 m a.g.l., and interpret the dataset in terms of constraints on regional methanol sources and seasonality. The seasonal cycle of methanol concentrations observed at the KCMP tall tower is generally similar to that simulated by a global 3-D chemical transport model (GEOS-Chem, driven with MEGANv2.0 biogenic emissions except the seasonal peak occurs ~1 month earlier in the observations, apparently reflecting a model underestimate of emission rates for younger versus older leaves. Based on a source tracer approach, which we evaluate using GEOS-Chem and with multiple tracers, we estimate that anthropogenic emissions account for approximately 40 % of ambient methanol abundance during winter and 10 % during summer. During daytime in summer, methanol concentrations increase exponentially with temperature, reflecting the temperature sensitivity of the biogenic source, and the observed temperature dependence is statistically consistent with that in the model. Nevertheless, summertime concentrations are underestimated by on average 35 % in the model for this region. The seasonal importance of methanol as a source of formaldehyde (HCHO and carbon monoxide (CO is highest in spring through early summer, when biogenic methanol emissions are high but isoprene emissions are still relatively low. During that time observed methanol concentrations account for on average 20 % of the total CO and HCHO production rates as simulated by GEOS-Chem, compared to 12 % later in the summer and 12 % on an annual average basis. The biased seasonality in the model means that the photochemical role for methanol early in the growing season is presently underestimated.

  20. Vacuum-Ultraviolet (VUV) Photoionization of Small Methanol and Methanol-Water Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Kostko, Oleg; Belau, Leonid; Wilson, Kevin R.; Ahmed, Musahid

    2008-04-24

    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+, (CH3OH)2+, (CH3OH)nH+ (n = 1-9), and (CH3OH)n(H2O)H+ (n = 2-9) as a function of photon energy. With an increasein the water content in the molecular beam, there is an enhancement of photoionization intensity for the methanol dimer and protonated methanol monomer at threshold. These results are compared and contrasted to previous experimental observations.

  1. Vacuum-ultraviolet (VUV) photoionization of small methanol and methanol-water clusters

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Musahid; Ahmed, Musahid; Wilson, Kevin R.; Belau, Leonid; Kostko, Oleg

    2008-05-12

    In this work we report on thevacuum-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 vacuumultraviolet 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.

  2. Microfluidic distillation chip for methanol concentration detection.

    Science.gov (United States)

    Wang, Yao-Nan; Liu, Chan-Chiung; Yang, Ruey-Jen; Ju, Wei-Jhong; Fu, Lung-Ming

    2016-03-17

    An integrated microfluidic distillation system is proposed for separating a mixed ethanol-methanol-water solution into its constituent components. The microfluidic chip is fabricated using a CO2 laser system and comprises a serpentine channel, a boiling zone, a heating zone, and a cooled collection chamber filled with de-ionized (DI) water. In the proposed device, the ethanol-methanol-water solution is injected into the microfluidic chip and driven through the serpentine channel and into the collection chamber by means of a nitrogen carrier gas. Following the distillation process, the ethanol-methanol vapor flows into the collection chamber and condenses into the DI water. The resulting solution is removed from the collection tank and reacted with a mixed indicator. Finally, the methanol concentration is inversely derived from the absorbance measurements obtained using a spectrophotometer. The experimental results show the proposed microfluidic system achieves an average methanol distillation efficiency of 97%. The practicality of the proposed device is demonstrated by detecting the methanol concentrations of two commercial fruit wines. It is shown that the measured concentration values deviate by no more than 3% from those obtained using a conventional bench top system.

  3. Class I methanol masers: Masers with EGOs

    CERN Document Server

    Chen, Xi; Shen, Zhi-Qiang

    2009-01-01

    We have compared the results of a number of published class I methanol maser surveys with the catalogue of high-mass outflow candidates identified from the GLIMPSE survey (known as extended green objects or EGOs). We find class I methanol masers associated with approximately two-thirds of EGOs. Although the association between outflows and class I methanol masers has long been postulated on the basis of detailed studies of a small number of sources, this result demonstrates the relationship for the first time on a statistical basis. Despite the publication of a number of searches for class I methanol masers, a close physical association with another astrophysical object which could be targeted for the search is still lacking. The close association between class I methanol masers and EGOs therefore provides a large catalogue of candidate sources, most of which have not previously been searched for class I methanol masers. Interstellar masers and outflows have both been proposed to trace an evolutionary sequenc...

  4. Star-forming protoclusters associated with methanol masers

    CERN Document Server

    Minier, V; Hill, T; Pestalozzi, M R; Purcell, C R; Garay, G; Walsh, A; Longmore, S N

    2004-01-01

    We present a multiwavelength study of five methanol maser sites which are not directly associated with a strong ($>100$ mJy) radio continuum source: G 31.28+0.06, G 59.78+0.06, G 173.49+2.42 (S231, S233IR), G 188.95+0.89 (S252, AFGL5180) and G 192.60-0.05 (S255IR). These radio-quiet methanol maser sites are often interpreted as precursors of ultra-compact \\ion{H}{ii} regions or massive protostar sites. In this work, the environment of methanol masers is probed from mid-IR to millimetre wavelengths at angular resolutions of $8''-34''$. Spectral energy distribution (SED) diagrams for each site are presented, together with mass and luminosity estimates. Each radio-quiet maser site is always associated with a massive ($>50$ M$_{\\odot}$), deeply embedded ($A_v>40$ mag) and very luminous ($>10^4$ S L$_{\\odot}$) molecular clump, with $L_{total}{\\propto}M_{gas}^{0.75}$. These physical properties characterise massive star-forming clumps in earlier evolutionary phases than \\ion{H}{ii} regions. In addition, colder gas c...

  5. Poly[[(methanol(μ4-2,4,5,6-tetrafluorobenzene-1,3-dicarboxylatocopper(II] methanol monosolvate

    Directory of Open Access Journals (Sweden)

    Dan Yan

    2012-06-01

    Full Text Available In the title compound, {[Cu(C8F4O4(CH3OH]·CH3OH}n, two CuII atoms are bridged by four carboxylate groups, forming the well known paddle-wheel secondary building unit (SBU with axial methanol ligands. In each ligand, the dihedral angles between the benzene ring and the two carboxylate groups are 80.43 (17 and 62.5 (4°. Within each SBU, the four carboxylate groups come from four symmetry-equivalent tetrafluoroisophthalate ligands. Each tetrafluoroisophthalate group connects two SBUs, forming a layered structure . In the crystal, O—H...O hydrogen bonds involving the free and ligated methanol molecules link the molecules into a three-dimensional supramolecular network.

  6. In vitro antimicrobial activity of methanolic leaf extract of Psidium guajava L.

    Directory of Open Access Journals (Sweden)

    Anju Dhiman

    2011-01-01

    Full Text Available Aim: This study was designed to examine the chemical composition and in vitro antimicrobial potential of methanolic extract of Psidium guajava Linn (Myrtaceae. Materials and Methods: The inhibitory effect of methanolic extract of P. guajava was tested against three bacterial and two fungal strains by using the paper disc diffusion method. Results: The methanolic extract exhibited antibacterial activity against E. coli with minimum inhibitory concentration, 0.78 μg/ml, minimum bactericidal concentration of 50 μg/ml, and appreciable antifungal activity with minimum inhibitory concentration of 12.5 μg/ml. Preliminary phytochemical analysis of methanolic extract revealed the presence of antimicrobial compounds such as flavonoids, steroids, and tannins, which may contribute for the antimicrobial action of P. guajava. Conclusion: The extract was found to be bacteriostatic and fungistatic in action.

  7. Hepatoprotective activity of methanolic extract of Mussaenda philippica (stems against anti-tubercular drugs induced hepatotoxicity

    Directory of Open Access Journals (Sweden)

    Swarnalatha Reddy Dugasani

    2014-12-01

    Full Text Available The present study was designed to evaluate the hepatoprotective effect of methanolic extract of Mussaenda philippica against isoniazid and rifampicin induced hepatotoxicity in experimental rats. Six groups of six rat were selected for the study. Methanolic extract of Mussaendaphilippicaat a dose of 100, 200 and 400 mg/kg as well as silymarin (50 mg/kg were administered orally once daily for 14 d in isoniazid and rifampicin group. The serum levels of glutamic oxaloacetic transaminase (SGOT, glutamate pyruvate transaminase (SGPT, alkaline phosphatase, and bilirubin were estimated along with total protein. Histopathological analysis was carried out to assess injury to the liver. The altered biochemical parameters were significantly reverting back by the methanolic extract treatment. Histopathology also supported the biochemical variation. From this study it has been concluded that the methanolic extract of Mussaendaphilippicashows significant hepatoprotective activity.

  8. Yeast methylotrophy and autophagy in a methanol-oscillating environment on growing Arabidopsis thaliana leaves.

    Directory of Open Access Journals (Sweden)

    Kosuke Kawaguchi

    Full Text Available The yeast Candida boidinii capable of growth on methanol proliferates and survives on the leaves of Arabidopsis thaliana. The local methanol concentration at the phyllosphere of growing A. thaliana exhibited daily periodicity, and yeast cells responded by altering both the expression of methanol-inducible genes and peroxisome proliferation. Even under these dynamically changing environmental conditions, yeast cells proliferated 3 to 4 times in 11 days. Among the C1-metabolic enzymes, enzymes in the methanol assimilation pathway, but not formaldehyde dissimilation or anti-oxidizing enzymes, were necessary for yeast proliferation at the phyllosphere. Furthermore, both peroxisome assembly and pexophagy, a selective autophagy pathway that degrades peroxisomes, were necessary for phyllospheric proliferation. Thus, the present study sheds light on the life cycle and physiology of yeast in the natural environment at both the molecular and cellular levels.

  9. Fabrication and Characterization of a Micro Methanol Sensor Using the CMOS-MEMS Technique

    Directory of Open Access Journals (Sweden)

    Chien-Fu Fong

    2015-10-01

    Full Text Available A methanol microsensor integrated with a micro heater manufactured using the complementary metal oxide semiconductor (CMOS-microelectromechanical system (MEMS technique was presented. The sensor has a capability of detecting low concentration methanol gas. Structure of the sensor is composed of interdigitated electrodes, a sensitive film and a heater. The heater located under the interdigitated electrodes is utilized to provide a working temperature to the sensitive film. The sensitive film prepared by the sol-gel method is tin dioxide doped cadmium sulfide, which is deposited on the interdigitated electrodes. To obtain the suspended structure and deposit the sensitive film, the sensor needs a post-CMOS process to etch the sacrificial silicon dioxide layer and silicon substrate. The methanol senor is a resistive type. A readout circuit converts the resistance variation of the sensor into the output voltage. The experimental results show that the methanol sensor has a sensitivity of 0.18 V/ppm.

  10. Optimal Fixed Bed Reactor Network Configuration for the Efficient Recycling of CO2 into Methanol

    Directory of Open Access Journals (Sweden)

    Ali Elkamel

    2009-04-01

    Full Text Available An optimal design strategy of a network of fixed bed reactors for Methanol Production (MP is proposed in this study. Both methanol production and profit spanning a production period of eight years have been set as objective functions to find the optimal production network. The conservation of mass and energy laws on a heterogeneous model of a single industrial methanol reactor was first developed. The model was solved numerically and was validated with industrial plant data. Different reactor network arrangements were then simulated in order to find an optimal superstructure. It was found that a structure of four reactors (two in series in parallel with another two in series provide maximum production rate. The application of the more realistic objective function of profit showed that a configuration of two parallel reactors is the best configuration. This optimal structure produces 92 tons/day more methanol than a single reactor.

  11. Direct Methanol Fuel Cell (DMFC) Battery Replacement Program

    Science.gov (United States)

    2013-01-29

    required for maximum performance of electrochemical flow reactors . A reactant stream will favor the path of least resistance, potentially starving re...gions of the electrode assembly and lowering reactor efficiency. Array fuel cells are ideal for evaluation of catalytic layers, gas diffusion...layers, solid electrolytes , electrode fabrica- tion methods and flow uniformity. The coupling of Array fuel cell analysis with a modular flow-field

  12. Production of methanol/DME from biomass

    Energy Technology Data Exchange (ETDEWEB)

    Ahrenfeldt, J.; Birk Henriksen, U.; Muenster-Swendsen, J.; Fink, A.; Roengaard Clausen, L.; Munkholt Christensen, J.; Qin, K.; Lin, W.; Arendt Jensen, P.; Degn Jensen, A.

    2011-07-01

    In this project the production of DME/methanol from biomass has been investigated. Production of DME/methanol from biomass requires the use of a gasifier to transform the solid fuel to a synthesis gas (syngas) - this syngas can then be catalytically converted to DME/methanol. Two different gasifier types have been investigated in this project: 1) The Two-Stage Gasifier (Viking Gasifier), designed to produce a very clean gas to be used in a gas engine, has been connected to a lab-scale methanol plant, to prove that the gas from the gasifier could be used for methanol production with a minimum of gas cleaning. This was proved by experiments. Thermodynamic computer models of DME and methanol plants based on using the Two-Stage Gasification concept were created to show the potential of such plants. The models showed that the potential biomass to DME/methanol + net electricity energy efficiency was 51-58% (LHV). By using waste heat from the plants for district heating, the total energy efficiencies could reach 87-88% (LHV). 2) A lab-scale electrically heated entrained flow gasifier has been used to gasify wood and straw. Entrained flow gasifiers are today the preferred gasifier type for commercial coal gasification, but little information exists on using these types of gasifiers for biomass gasification. The experiments performed provided quantitative data on product and gas composition as a function of operation conditions. Biomass can be gasified with less oxygen consumption compared to coal. The organic fraction of the biomass that is not converted to gas appears as soot. Thermodynamic computer models of DME and methanol plants based on using entrained flow gasification were created to show the potential of such plants. These models showed that the potential torrefied biomass to DME/methanol + net electricity energy efficiency was 65-71% (LHV). Different routes to produce liquid transport fuels from biomass are possible. They include production of RME (rapeseed oil

  13. Methanol Along the Path from Envelope to Protoplanetary Disc

    CERN Document Server

    Drozdovskaya, Maria N; Visser, Ruud; Harsono, Daniel; van Dishoeck, Ewine F

    2014-01-01

    Interstellar methanol is considered to be a parent species of larger, more complex organic molecules. A physicochemical simulation of infalling parcels of matter is performed for a low-mass star-forming system to trace the chemical evolution from cloud to disc. An axisymmetric 2D semi-analytic model generates the time-dependent density and velocity distributions, and full continuum radiative transfer is performed to calculate the dust temperature and the UV radiation field at each position as a function of time. A comprehensive gas-grain chemical network is employed to compute the chemical abundances along infall trajectories. Two physical scenarios are studied, one in which the dominant disc growth mechanism is viscous spreading, and another in which continuous infall of matter prevails. The results show that the infall path influences the abundance of methanol entering each type of disc, ranging from complete loss of methanol to an enhancement by a factor of > 1 relative to the prestellar phase. Critical ch...

  14. Visual evoked potentials in patients after methanol poisoning

    Directory of Open Access Journals (Sweden)

    Pavel Urban

    2016-06-01

    Full Text Available Objectives: We report the results of the visual evoked potentials (VEP examination in patients after severe poisoning by methanol. Material and Methods: The group of 47 patients (38 males and 9 females was assembled out of persons who survived an outbreak of poisoning by the methanol adulterated alcohol beverages, which happened in the Czech Republic in 2012–2013. The visual evoked potentials examination was performed using monocular checkerboard pattern-reversal stimulation. Two criteria of abnormality were chosen: missing evoked response, and wave P1 latency > 117 ms. Non-parametric statistical methods (median, range, and the median test were used to analyze factors influencing the VEP abnormality. Results: The visual evoked potential was abnormal in 20 patients (43%, 5 of them had normal visual acuity on the Snellen chart. The VEP abnormality did not correlate significantly with initial serum concentrations of methanol, formic acid or lactate; however, it showed statistically significant inverse relation to the initial serum pH: the subgroup with the abnormal VEP had significantly lower median pH in comparison with the subgroup with the normal VEP (7.16 vs. 7.34, p = 0.04. The abnormality was not related to chronic alcohol abuse. Conclusions: The visual evoked potentials examination appeared sensitive enough to detected even subclinical impairment of the optic system. Metabolic acidosis is likely to be the key factor related to the development of visual damage induced by methanol. The examination performed with a delay of 1–9 months after the poisoning documented the situation relatively early after the event. It is considered as a baseline for the planned long-term follow-up of the patients, which will make it possible to assess the dynamics of the observed changes, their reversibility, and the occurrence of potential late sequelae.

  15. Methanol-driven enhanced biological phosphorus removal with a syntrophic consortium.

    Science.gov (United States)

    Tayà, Carlota; Guerrero, Javier; Vanneste, Gianni; Guisasola, Albert; Baeza, Juan A

    2013-02-01

    The presence of suitable carbon sources for enhanced biological phosphorus removal (EBPR) plays a key role in phosphorus removal from wastewater in urban WWTP. For wastewaters with low volatile fatty acids (VFAs) content, an external carbon addition is necessary. As methanol is the most commonly external carbon source used for denitrification it could be a priori a promising alternative, but previous attempts to use it for EBPR have failed. This study is the first successful report of methanol utilization as external carbon source for EBPR. Since a direct replacement strategy (i.e., supply of methanol as a sole carbon source to a propionic-fed PAO-enriched sludge) failed, a novel process was designed and implemented successfully: development of a consortium with anaerobic biomass and polyphosphate accumulating organisms (PAOs). Methanol-degrading acetogens were (i) selected against other anaerobic methanol degraders from an anaerobic sludge; (ii) subjected to conventional EBPR conditions (anaerobic + aerobic); and (iii) bioaugmented with PAOs. EBPR with methanol as a sole carbon source was sustained in a mid-term basis with this procedure. Copyright © 2012 Wiley Periodicals, Inc.

  16. Methanol utilizing Desulfotomaculum species utilizes hydrogen in a methanol-fed sulfate-reducing bioreactor

    NARCIS (Netherlands)

    Balk, M.; Weijma, J.; Goorissen, H.P.; Ronteltap, M.; Hansen, T.A.; Stams, A.J.M.

    2007-01-01

    A sulfate-reducing bacterium, strain WW1, was isolated from a thermophilic bioreactor operated at 65 degrees C with methanol as sole energy source in the presence of sulfate. Growth of strain WW1 on methanol or acetate was inhibited at a sulfide concentration of 200 mg l(-1), while on H-2/CO2, no ap

  17. Dimethyl ether production from methanol and/or syngas

    Energy Technology Data Exchange (ETDEWEB)

    Dagle, Robert A; Wang, Yong; Baker, Eddie G; Hu, Jianli

    2015-02-17

    Disclosed are methods for producing dimethyl ether (DME) from methanol and for producing DME directly from syngas, such as syngas from biomass. Also disclosed are apparatus for DME production. The disclosed processes generally function at higher temperatures with lower contact times and at lower pressures than conventional processes so as to produce higher DME yields than do conventional processes. Certain embodiments of the processes are carried out in reactors providing greater surface to volume ratios than the presently used DME reactors. Certain embodiments of the processes are carried out in systems comprising multiple microchannel reactors.

  18. Mechanistic and kinetic investigations on the role of methanol and dimethyl ether in the Methanol-To-Hydrocarbons reaction

    OpenAIRE

    Espín, Juan Salvador Martínez

    2017-01-01

    The main scope of this PhD thesis was to gain knowledge on the mechanistic and kinetic behavior of methanol and DME in the industrially relevant Methanol-To-Hydrocarbons (MTH) reaction with the use of zeolitic materials as catalysts. Industrial MTH processes use methanol, DME or combined methanol/DME feeds over zeolitic catalysts. Methanol and its dehydration product, DME, are conventionally attributed an analogous behavior in MTH; however, a thorough investigation on the theme is still missi...

  19. Transformations of lead 1,3-propylenediaminetetraacetate to its MOF products for the selective adsorption of methanol

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Jun-Wei; Li, Xing; Zheng, Jian-Mei; Dong, Xin, E-mail: dxin@xmu.edu.cn; Zhou, Zhao-Hui, E-mail: zhzhou@xmu.edu.cn

    2016-05-15

    Water soluble coordination polymer of potassium lead 1,3-propylenediaminetetraacetate {K_4[Pb_2(1,3-pdta)_2]·6H_2O}{sub n} (1) and its insoluble products {[Pb(1,3-H_2pdta)(H_2O)]·2H_2O}{sub n} (2), {[Pb_2(1,3-pdta)(H_2O)_4]·4H_2O}{sub n} (3) and [Pb{sub 2}(1,3-pdta)(H{sub 2}O){sub 2}]{sub n} (4) were obtained from the direct reactions of lead nitrate with 1,3-propylenediaminetetraacetic acid in different conditions (1,3-H{sub 4}pdta=1,3-propylenediaminetetraacetic acid). The former 1 could be converted to the insoluble products of {[Pb_2(1,3-pdta)(H_2O)_4]·4H_2O}{sub n} (3) and [Pb{sub 2}(1,3-pdta)(H{sub 2}O){sub 2}]{sub n} (4) in weak acidic solution. The complexes have been full characterized by EA, FT-IR, solution and solid state {sup 13}C NMR spectra, thermogravimetric and structural analyses. Interestingly, 3 contains a unique (H{sub 2}O){sub 26} cluster and a 5.2 Å pore after eliminating the guest water molecules, which exhibits reversible adsorption for methanol. This is confirmed by PXRD and solid state {sup 13}C NMR analyses. Nano-confined methanol in microporous structure has been observed based on the large downfield shift of {sup 13}C NMR signal (Δδ 9.72 ppm), attributing to the methyl group in methanol. - Graphical abstract: Water soluble coordination polymer K{sub 4n}[Pb{sub 2}(1,3-pdta){sub 2}]{sub n}·6nH{sub 2}O (1) is converted to its insoluble product [Pb{sub 2}(1,3-pdta)(H{sub 2}O){sub 4}]{sub n}·4nH{sub 2}O (3), which contains a unique (H{sub 2}O){sub 26} cluster and exhibits reversible adsorption for methanol. - Highlights: • Water-soluble coordination polymer was constructed by lead propylenediaminetetraacetate. • Its MOF product has a unique (H{sub 2}O){sub 26} cluster. • The product exhibits reversible adsorption for methanol.

  20. Optimization of HPLC method for the isolation of Hypericum perforatum L. methanol extract

    Directory of Open Access Journals (Sweden)

    Stamenković, J.

    2013-12-01

    Full Text Available St. John's Wort (Hypericum perforatum L. is one of the most studied plant species in the family Hypericaceae. The aim of this study was the identification of the constituents of methanol extract of H. perforatum and optimization of conditions for their isolation. The main components of the methanol extract were isolated on preparative ZORBAX Eclipse XDB C18 column with solvent system consisting of methanol and 1x10-2 M ammonium acetate in water. Constituents of the extract were identified by comparing their retention times with the retention times of the standards, with the literature data and the UV spectra. By varying the conditions of chromatography, the optimal conditions for isolation of the methanol extract constituents were determined: mobile phase consisting of methanol and 1x10-2 M ammonium acetate in water in ratio 1 : 1, sample concentration 100 mg/mL, sample volume 30 µL, flow 2 mL/min. Under these conditions 7 components of the methanol extract were isolated.