Iranian Research Organization for Science and Technology (IROST)Hydrogen, Fuel Cell & Energy Storage2980-85371220140913Reforming Integrated with Oxidation in Micro-Heat Exchanger Reactor with Circular Micro-Channels65745410.22104/ijhfc.2014.54ENFaramarzHormoziFaculty of Chemical, Petroleum and Gas Engineering,
Semnan University, Semnan, IranElhamOmidbakhsh AmiriFaculty of Chemical, Petroleum and Gas Engineering, Semnan University, Semnan, IranHusseinJelvehFaculty of Chemical, Petroleum and Gas Engineering, Semnan University, Semnan, IranJournal Article20130821Steam reforming integrated with oxidation of methanol was considered with numerical simulation. The parallel micro-channels with circular cross sections were used. Because when the catalytic deposited inside the rectangular micro-channels, it fills up the edges. Hence, the approximation of a cylindrical channel is appropriate. Effect of this changing in cross section was considered and results show conversion is lower in circular model. Also, effects of operating conditions such as inlet temperature, feed flow rate, inlet composition (as steam/carbon ratio) and geometry parameters such as the distance between two rows and two columns were considered. The results show that with increasing inlet temperature and steam/carbon ratio, methanol conversion increases while with increasing feed flow rate, methanol conversion decreases. Geometry parameters are another consideration and the results show that with increasing t1 (the distance between oxidation and steam reforming micro-channels) methanol conversion decreases and with increasing t1/t2 ratio (t2 is the distance between two oxidation micro-channels or two steam reforming micro-channels), methanol conversion increases firstly and then keep almost constant.Iranian Research Organization for Science and Technology (IROST)Hydrogen, Fuel Cell & Energy Storage2980-85371220140913Single walled carbon nanotube in the reaction layer of gas diffusion electrode for oxygen reduction reaction75825510.22104/ijhfc.2014.55ENMehdiKheirmandDepartment of Chemistry, School of basic sciences, Yasouj University, Yasouj, IranRasolAbdullah MirzaieFuel Cell Research Laboratory, Department of Chemistry, Faculty of Science, Shahid Rajaee Teacher Training University, Tehran, Iran.RahilYazdanshenasFuel Cell Research Laboratory, Department of Chemistry, Faculty of Science, Shahid Rajaee Teacher Training University, Tehran, Iran.AhmadNozad GolikandMaterial Research Center, Isfahan, IranJournal Article20131026In this paper, the effect of surface area of reaction layers in gas diffusion electrodes on oxygen reduction reaction was investigated. For this purpose, various amounts (0.1, 0.2, 0.3, 0.4, 0.5, 1, 1.5 and zero %wt of total loading of reaction layer) of single walled carbon nanotube (SWCNT) were inserted in the reaction layer. The performance of gas diffusion electrodes for oxygen reduction reaction was studied in a three-electrode half-cell system, via linear sweep voltammetry (LSV), cyclic voltammetry (CV), chronoamperometry (CHA) and impedance analysis. The results show that, the existence of SWCNT in the reaction layer improves the exchange current density of ORR, the symmetry factor changed between 0.51 and 0.83, as a whole in the optimized condition (0.4% wt .SWCNT) tendency of gas diffusion electrode for ORR is increased. The addition, influences significantly in electrochemical surface area and the gas diffusion electrode with 0.4%wt SWCNT has lowest charge transfer resistance respect to other electrodes. Our results indicated that the best performance obtains for an electrode with 0.4% single walled carbon nanotube.Iranian Research Organization for Science and Technology (IROST)Hydrogen, Fuel Cell & Energy Storage2980-85371220140913Synthesis, characterization and hydrogen storage properties of Mm(Ni,Co,Mn,Al)5 alloy83945610.22104/ijhfc.2014.56ENSeyyed MojtabaAlaviSadrMagnetism and Superconducting Research Laboratory, Department of Physics, Faculty of Science, University of Birjand, Birjand, Iran.HadiArabiDepartment of physics, Ferdowsi University of MashhadFaizPourarianDepartment of Material Science and Engineering, Carnegie Mellon University, Pittsburgh, PA, USAJournal Article20140211The hydrogenation characterizations of the hydrogen storage alloy MmNi4.22Co0.48Mn0.15Al0.15 (Mm= mischmetal), and the effect of hydrogenation/dehydrogenation (H/D) cycling on its structural and morphological properties are investigated. The results indicate that after several H/D cycles the alloy was pulverized into fine particles, but it kept its hexagonal CaCu5-type structure. The pressure-composition (PC) isotherms for hydrogen absorption/desorption and absorption kinetic were measured in temperature range of 293-338 K. The absorption plateau pressures were determined to be ~ 0.51, 1.22 and 2.49 bar at 293, 313 and 33 K respectively, with a maximum hydrogen storage capacity of about 5.78 at 293 K. The enthalpy (H), entropy (S) and the activation energy of reactions (Ea) were also calculated. The results show that the hydrogenation reaction rate increases with an increase in the operating temperature or pressure. The Jander diffusion (JDM) and Johnson-Mehl-Avrami (JMA) models were employed and the kinetic of hydrogenation was analyzed in detail for hydriding reaction (rate controlling steps) mechanism. The obtained results indicate that the MmNi4.22Co0.48Mn0.15Al0.15 alloy has potential to be suitable for use in practical applications.Iranian Research Organization for Science and Technology (IROST)Hydrogen, Fuel Cell & Energy Storage2980-85371220140913Modeling of measurement error in refractive index determination of fuel cell using neural network and genetic algorithm951043010.22104/ijhfc.2014.30ENSaeedOlyaeeShahid Rajaee Teacher Training UniversityRezaEbrahimpourSRTTUSomayehEsfandehSRTTUJournal Article20140228Abstract: In this paper, a method for determination of refractive index in membrane of fuel cell on basis of three-longitudinal-mode laser heterodyne interferometer is presented. The optical path difference between the target and reference paths is fixed and phase shift is then calculated in terms of refractive index shift. The measurement accuracy of this system is limited by nonlinearity error. In this study, nonlinearity error is modeled by multi-layer perceptrons (MLPs) and stacked generalization method (Stacking), using two learning methods; back propagation (BP) and genetic algorithm. Training neural networks with genetic algorithm, improves modeling of nonlinearity error in this system. In the proposed technique, a real code version of genetic algorithm is used. Parameters and genetic operators are set and designed accurately. The results indicate that the nonlinearity error can be effectively modeled by training the stacking with the genetic algorithm which has minimum mean square error (MSE). <br />Keywords: Fuel cell, Genetic algorithm, Heterodyne interferometer, Multi-layer perceptrons, Nonlinearity error, Refractive index, Stacked Generalization.Iranian Research Organization for Science and Technology (IROST)Hydrogen, Fuel Cell & Energy Storage2980-85371220140913Novel PVA/La2Ce2O7 hybrid nanocomposite membranes for application in proton exchange membrane fuel cells1051125210.22104/ijhfc.2014.52ENMehranJavanbakhtDepartment of Chemistry, Amirkabir University of Technology, Tehran, IranKhadijehHooshyariDepartment of Chemistry, Amirkabir University of Technology, Tehran, IranMortezaEnhessariDepartment of Chemistry, Naragh Branch, Islamic Azad University, Naragh, IranHosseinBeydaghiDepartment of Chemistry, Amirkabir University of Technology, Tehran, IranJournal Article20140417Proton exchange membrane fuel cells (PEMFCs) are electrochemical devices that show the highest power densities compared to the other type of fuel cell. In this work, nanocomposite membranes used for proton exchange membrane fuel cells as poly(vinyl alcohol)/La2Ce2O7 (PVA-LC) with the aim of increasing the water uptake and proton conductivity. Glutaraldehyde (GA) was used as cross linking agent of PVA matrix. PVA-LC nanocomposite membranes have been prepared with solutions casting method. The significant improvement has been achieved via the synergetic combination of organic and inorganic phases. Nanocomposite membranes were structurally, morphologically and electrochemically considered by FTIR, SEM and ELS, respectively. The results exhibited that the proton conductivity and the water uptake of the nanocomposite membranes were higher than that of the PVA membrane. PVA-LC nanocomposite membranes containing 4 wt.% of La2Ce2O7 nanoparticles displayed a high proton conductivity (0.019 S/cm). The highest peak power density of the PEMFC using PVA-LC nanocomposite membrane at ambient temperature was 19 mW/cm2. The proposed PVA-LC nanocomposite membranes appear to be a viable candidate for future PEMFCs applications.Iranian Research Organization for Science and Technology (IROST)Hydrogen, Fuel Cell & Energy Storage2980-85371220140913Preparation of Nitrogen-Doped Graphene By Solvothermal Process as Supporting Material for Fuel Cell Catalysts1131195710.22104/ijhfc.2014.57ENHosnaGhanbarlouSchool of Chemical Engineering, Iran University of Science and TechnologySoosanRowshanzamirGreen Research Center (GRC) & School of Chemical Engineering (SChE)
Iran University of Science & TechnologyMohammad JavadParnianSchool of Chemical Engineering, Iran University of Science and TechnologyBagherKazeminasabDepartment of energy engineering, Science and Research Branch, Islamic Azad University, Tehran.Journal Article20140517Development of efficient electrocatalysts for oxygen reduction reaction (ORR) is one of the most important issues for optimizing the performance of fuel cells and metal-air batteries. The introduction of nitrogen into carbon nanostructures has created new pathways for the development of non-precious electrocatalysts in fuel cells. In this work, nitrogen-doped graphene (NG) was synthesized by a low temperature solvothermal process to use as catalyst supports for oxygen reduction reactions (ORR). The morphology of the NG was studied using scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. X-ray photoelectron spectroscopy showed that graphitic (Quaternary), pyridinic and pyridinic oxidized nitrogen formed by designed reaction and these types of nitrogen configurations has been found to be responsible for the ORR catalytic activity of N-doped carbon material. Cyclic voltammetry and linear sweep voltammetry were used to measure electrocatalytic activity. Electrochemical characterization reveal that the produced NG not only as support but also as catalyst has good catalytic activity for oxygen reduction reaction in alkaline media.Iranian Research Organization for Science and Technology (IROST)Hydrogen, Fuel Cell & Energy Storage2980-85371220140913Co3O4 spinel protection coating for solid oxide fuel cell interconnect application1211315310.22104/ijhfc.2014.53ENRezaIrankhahMaterials and energy research centerBabakRaissiMaterials and energy research centerAmirMaghsoudipourmaterials and energy research centerJournal Article20140525In the present study, electrophoretic deposition (EPD) method in different electric fields (30 – 300 V / cm) was used to apply Co3O4 spinel coating to SUS 430 as SOFC interconnect. The coated and uncoated specimens were pre-sintered in air at 800 and 900 °C for 3 h followed by cyclic oxidation at 700 and 800 °C for 500 h, respectively. X-ray diffraction analysis (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) were used for characterization of the prepared samples. The results indicated that the electric field of 100 V was an effective voltage to obtain crack-free coating. A comparison between the oxidation resistance of coated and uncoated specimens indicated that the weight change of the coated specimen was larger than that of the uncoated one during the cyclic oxidation, so the Co3O4 coating is not effective for improving the oxidation resistance. According to the obtained results, the oxidation rate constant (Kp) for the coated specimens at 700 and 800 °C in air were 2.36×10-14 and 3.37×10-12gr2cm−4s−1, respectively.