The Experts below are selected from a list of 30960 Experts worldwide ranked by ideXlab platform
Jinsong Zhang - One of the best experts on this subject based on the ideXlab platform.
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kinetics of ru catalyzed Sodium Borohydride hydrolysis
Journal of Power Sources, 2007Co-Authors: Jinsong Zhang, T.s. Fisher, W N Delgass, Jay P. GoreAbstract:Abstract Chemical hydrides have been identified as a potential medium for on-board hydrogen storage, one of the most challenging technical barriers to the prospective transition from gasoline to hydrogen-powered vehicles. Systematic study of the feasibility of the Sodium Borohydride systems, and chemical-hydride systems more generally, requires detailed kinetic studies of the reaction for use in reactor modeling and system-level experiments. This work reports an experimental study of the kinetics of Sodium Borohydride hydrolysis with a Ru-on-carbon catalyst and a Langmuir-Hinshelwood kinetic model developed based on experimental data. The model assumes that the reaction consists of two important steps: the equilibrated adsorption of Sodium Borohydride on the surface of the catalyst and the reaction of the adsorbed species. The model successfully captures both the reaction's zero-order behavior at low temperatures and the first-order behavior at higher temperatures. Reaction rate constants at different temperatures are determined from the experimental data, and the activation energy is found to be 66.9 kJ mol −1 from an Arrhenius plot.
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Heat of reaction measurements of Sodium Borohydride alcoholysis and hydrolysis
International Journal of Hydrogen Energy, 2006Co-Authors: Jinsong Zhang, T.s. Fisher, Jay P. Gore, Debasis Hazra, P. Veeraraghavan RamachandranAbstract:Abstract On-board hydrogen storage has been identified as one of the most challenging technical barriers to the possible transition from gasoline to hydrogen powered vehicles. One common developmental system uses Sodium Borohydride and water to generate hydrogen. The system offers many advantages over other types of storage methods such as compressed hydrogen, liquid hydrogen and metal hydrides. However, previous reports on the heat of reaction of Sodium Borohydride hydrolysis are inconsistent. As a result, calorimetry measurements have been conducted to clarify this issue. The heat of reaction of Sodium Borohydride hydrolysis was measured to be - 210 ± 11 kJ / mol (exothermic). Furthermore, a recently filed patent indicates that Sodium Borohydride alcoholysis using ethylene glycol may offer some advantages over the aqueous system in terms of regeneration and low temperature operation. The heat of reaction of Sodium Borohydride with ethylene glycol was measured to be - 227 ± 8 kJ / mol (exothermic).
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Thermal Modeling of a Sodium Borohydride-Based Hydrogen Storage System
Heat Transfer Part B, 2005Co-Authors: Jinsong Zhang, T.s. FisherAbstract:On-board hydrogen storage has been identified as one of the most challenging technical barriers to the transition from gasoline- to hydrogen-powered vehicles. The Hydrogen-On-Demand system patented by Millennium Cell Inc. uses Sodium Borohydride as a hydrogen storage medium. Sodium Borohydride generates hydrogen when it reacts with water in the presence of catalyst. This system is much safer than other types of storage methods, such as compressed hydrogen, liquid hydrogen and metal hydrides. Nevertheless, it suffers severe disadvantages of adding significant amount of additional heat load to the already challenging thermal management problem of fuel-cell powered vehicles. To make this hydrogen storage method attractive, innovative thermal management should be adopted. This paper models the thermal behavior of a Sodium Borohydride-based hydrogen storage system and considers various potential methods to reduce the on-board cooling load by increasing reactor pressure and decreasing fuel cell pressure.Copyright © 2005 by ASME
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Heat of Reaction Measurements of Sodium Borohydride Alcoholysis
Heat Transfer: Volume 4, 2005Co-Authors: Jinsong Zhang, T.s. Fisher, Jay P. Gore, P. Veeraraghavan RamachandranAbstract:On-board hydrogen storage has been identified as one of the most challenging technical barriers to the transition from gasoline to hydrogen powered vehicles. The Hydrogen-On-Demand™ system patented by Millenium Cell Inc. uses Sodium Borohydride and water to generate hydrogen when needed. The system has many advantages over other types of storage methods such as compressed hydrogen, liquid hydrogen and metal hydrides. Nevertheless, the cost of making and regenerating Sodium Borohydride is too high. A recently filed patent indicates that Sodium Borohydride alcoholysis (e.g. using ethylene glycol) may offer some advantages over the aqueous system in terms of regeneration, which may significantly reduce the cost to regenerate Sodium Borohydride. To begin evaluating the energy efficiency of this new approach, this work experimentally characterizes the heat of reaction of Sodium Borohydride with ethylene glycol. The heat of reaction was measured to be approximately 220 kJ/mol (exothermic). For the Sodium Borohydride and water reaction, two different heat of reaction values have been reported in prior literature. The present work shows that the heats of reaction for both Sodium Borohydride hydrolysis and alcoholysis are both near 220 kJ/mol exothermically.© 2005 ASME
Jay P. Gore - One of the best experts on this subject based on the ideXlab platform.
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kinetics of ru catalyzed Sodium Borohydride hydrolysis
Journal of Power Sources, 2007Co-Authors: Jinsong Zhang, T.s. Fisher, W N Delgass, Jay P. GoreAbstract:Abstract Chemical hydrides have been identified as a potential medium for on-board hydrogen storage, one of the most challenging technical barriers to the prospective transition from gasoline to hydrogen-powered vehicles. Systematic study of the feasibility of the Sodium Borohydride systems, and chemical-hydride systems more generally, requires detailed kinetic studies of the reaction for use in reactor modeling and system-level experiments. This work reports an experimental study of the kinetics of Sodium Borohydride hydrolysis with a Ru-on-carbon catalyst and a Langmuir-Hinshelwood kinetic model developed based on experimental data. The model assumes that the reaction consists of two important steps: the equilibrated adsorption of Sodium Borohydride on the surface of the catalyst and the reaction of the adsorbed species. The model successfully captures both the reaction's zero-order behavior at low temperatures and the first-order behavior at higher temperatures. Reaction rate constants at different temperatures are determined from the experimental data, and the activation energy is found to be 66.9 kJ mol −1 from an Arrhenius plot.
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Heat of reaction measurements of Sodium Borohydride alcoholysis and hydrolysis
International Journal of Hydrogen Energy, 2006Co-Authors: Jinsong Zhang, T.s. Fisher, Jay P. Gore, Debasis Hazra, P. Veeraraghavan RamachandranAbstract:Abstract On-board hydrogen storage has been identified as one of the most challenging technical barriers to the possible transition from gasoline to hydrogen powered vehicles. One common developmental system uses Sodium Borohydride and water to generate hydrogen. The system offers many advantages over other types of storage methods such as compressed hydrogen, liquid hydrogen and metal hydrides. However, previous reports on the heat of reaction of Sodium Borohydride hydrolysis are inconsistent. As a result, calorimetry measurements have been conducted to clarify this issue. The heat of reaction of Sodium Borohydride hydrolysis was measured to be - 210 ± 11 kJ / mol (exothermic). Furthermore, a recently filed patent indicates that Sodium Borohydride alcoholysis using ethylene glycol may offer some advantages over the aqueous system in terms of regeneration and low temperature operation. The heat of reaction of Sodium Borohydride with ethylene glycol was measured to be - 227 ± 8 kJ / mol (exothermic).
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Heat of Reaction Measurements of Sodium Borohydride Alcoholysis
Heat Transfer: Volume 4, 2005Co-Authors: Jinsong Zhang, T.s. Fisher, Jay P. Gore, P. Veeraraghavan RamachandranAbstract:On-board hydrogen storage has been identified as one of the most challenging technical barriers to the transition from gasoline to hydrogen powered vehicles. The Hydrogen-On-Demand™ system patented by Millenium Cell Inc. uses Sodium Borohydride and water to generate hydrogen when needed. The system has many advantages over other types of storage methods such as compressed hydrogen, liquid hydrogen and metal hydrides. Nevertheless, the cost of making and regenerating Sodium Borohydride is too high. A recently filed patent indicates that Sodium Borohydride alcoholysis (e.g. using ethylene glycol) may offer some advantages over the aqueous system in terms of regeneration, which may significantly reduce the cost to regenerate Sodium Borohydride. To begin evaluating the energy efficiency of this new approach, this work experimentally characterizes the heat of reaction of Sodium Borohydride with ethylene glycol. The heat of reaction was measured to be approximately 220 kJ/mol (exothermic). For the Sodium Borohydride and water reaction, two different heat of reaction values have been reported in prior literature. The present work shows that the heats of reaction for both Sodium Borohydride hydrolysis and alcoholysis are both near 220 kJ/mol exothermically.© 2005 ASME
Michael A. Matthews - One of the best experts on this subject based on the ideXlab platform.
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Hydrolysis of Sodium Borohydride in concentrated aqueous solution
International Journal of Hydrogen Energy, 2011Co-Authors: Michael A. MatthewsAbstract:Abstract Sodium Borohydride is being commercialized to provide hydrogen storage for portable fuel cells. Prior kinetic studies have focused on catalytic hydrolysis of dilute aqueous solutions at room temperature. This work reports on a new NMR method for studying the kinetics of non-catalyzed Sodium Borohydride hydrolysis in highly concentrated solutions. The effects of initial NaBH4 concentration, temperature and pH on conversion are studied. It is found that higher initial NaBH4 concentration and higher temperature both improve the reaction rate. The reaction rate is slowed down with increasing pH of basic solutions and is accelerated with decreasing pH of acidic solutions. In addition, temperature effect seems to be more important than that of the acidic pH on the reaction rate.
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Hydrolysis of Sodium Borohydride with steam
International Journal of Hydrogen Energy, 2007Co-Authors: Eyma Y. Marrero-alfonso, Joshua R. Gray, Thomas A. Davis, Michael A. MatthewsAbstract:Abstract The reaction of Sodium Borohydride with steam produces hydrogen gas and a hydrated solid. Unlike the reaction in liquid water, up to 95% yield of hydrogen is obtained with pure steam without a catalyst. Liquid promoters (methanol and acetic acid) at concentrations of 1 mol% do not enhance the reaction rate, although acetic acid improves the hydrogen yield slightly.
Halil Ibrahim Sarac - One of the best experts on this subject based on the ideXlab platform.
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influences of Sodium Borohydride concentration on direct Borohydride fuel cell performance
Journal of Power Sources, 2010Co-Authors: Cenk Celik, Halil Ibrahim SaracAbstract:In this work, the effects of Sodium Borohydride concentration on the performance of direct Borohydride fuel cell, which consisted of Pd/C anode, Pt/C cathode and Na+ form Nafion (R) membrane as the electrolyte, have been investigated in steady state/steady-flow and uniform state/uniform-flow systems. The experimental results have revealed that the power density increased as the Sodium Borohydride concentration increased in the SSSF system. Peak power densities of 7.1, 10.1 and 11.7 MW cm(-2) have been obtained at 0.5, 1 and 1.5 M. respectively. However, the performance has decreased when the Sodium Borohydride concentration has been increased. and the fuel utilization ratios of 29.8%, 21.6% and 20.4% have been obtained at 0.5, 1 and 1.5 M, respectively in the USUF system. (C) 2009 Elsevier B.V. All rights reserved.
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Influences of Sodium Borohydride concentration on direct Borohydride fuel cell performance
Journal of Power Sources, 2010Co-Authors: Cenk Celik, Fatma Gul Boyaci San, Halil Ibrahim SaracAbstract:In this work, the effects of Sodium Borohydride concentration on the performance of direct Borohydride fuel cell, which consisted of Pd/C anode, Pt/C cathode and Na+ form Nafion (R) membrane as the electrolyte, have been investigated in steady state/steady-flow and uniform state/uniform-flow systems. The experimental results have revealed that the power density increased as the Sodium Borohydride concentration increased in the SSSF system. Peak power densities of 7.1, 10.1 and 11.7 MW cm(-2) have been obtained at 0.5, 1 and 1.5 M. respectively. However, the performance has decreased when the Sodium Borohydride concentration has been increased. and the fuel utilization ratios of 29.8%, 21.6% and 20.4% have been obtained at 0.5, 1 and 1.5 M, respectively in the USUF system. (C) 2009 Elsevier B.V. All rights reserved.
T.s. Fisher - One of the best experts on this subject based on the ideXlab platform.
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kinetics of ru catalyzed Sodium Borohydride hydrolysis
Journal of Power Sources, 2007Co-Authors: Jinsong Zhang, T.s. Fisher, W N Delgass, Jay P. GoreAbstract:Abstract Chemical hydrides have been identified as a potential medium for on-board hydrogen storage, one of the most challenging technical barriers to the prospective transition from gasoline to hydrogen-powered vehicles. Systematic study of the feasibility of the Sodium Borohydride systems, and chemical-hydride systems more generally, requires detailed kinetic studies of the reaction for use in reactor modeling and system-level experiments. This work reports an experimental study of the kinetics of Sodium Borohydride hydrolysis with a Ru-on-carbon catalyst and a Langmuir-Hinshelwood kinetic model developed based on experimental data. The model assumes that the reaction consists of two important steps: the equilibrated adsorption of Sodium Borohydride on the surface of the catalyst and the reaction of the adsorbed species. The model successfully captures both the reaction's zero-order behavior at low temperatures and the first-order behavior at higher temperatures. Reaction rate constants at different temperatures are determined from the experimental data, and the activation energy is found to be 66.9 kJ mol −1 from an Arrhenius plot.
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Heat of reaction measurements of Sodium Borohydride alcoholysis and hydrolysis
International Journal of Hydrogen Energy, 2006Co-Authors: Jinsong Zhang, T.s. Fisher, Jay P. Gore, Debasis Hazra, P. Veeraraghavan RamachandranAbstract:Abstract On-board hydrogen storage has been identified as one of the most challenging technical barriers to the possible transition from gasoline to hydrogen powered vehicles. One common developmental system uses Sodium Borohydride and water to generate hydrogen. The system offers many advantages over other types of storage methods such as compressed hydrogen, liquid hydrogen and metal hydrides. However, previous reports on the heat of reaction of Sodium Borohydride hydrolysis are inconsistent. As a result, calorimetry measurements have been conducted to clarify this issue. The heat of reaction of Sodium Borohydride hydrolysis was measured to be - 210 ± 11 kJ / mol (exothermic). Furthermore, a recently filed patent indicates that Sodium Borohydride alcoholysis using ethylene glycol may offer some advantages over the aqueous system in terms of regeneration and low temperature operation. The heat of reaction of Sodium Borohydride with ethylene glycol was measured to be - 227 ± 8 kJ / mol (exothermic).
-
Thermal Modeling of a Sodium Borohydride-Based Hydrogen Storage System
Heat Transfer Part B, 2005Co-Authors: Jinsong Zhang, T.s. FisherAbstract:On-board hydrogen storage has been identified as one of the most challenging technical barriers to the transition from gasoline- to hydrogen-powered vehicles. The Hydrogen-On-Demand system patented by Millennium Cell Inc. uses Sodium Borohydride as a hydrogen storage medium. Sodium Borohydride generates hydrogen when it reacts with water in the presence of catalyst. This system is much safer than other types of storage methods, such as compressed hydrogen, liquid hydrogen and metal hydrides. Nevertheless, it suffers severe disadvantages of adding significant amount of additional heat load to the already challenging thermal management problem of fuel-cell powered vehicles. To make this hydrogen storage method attractive, innovative thermal management should be adopted. This paper models the thermal behavior of a Sodium Borohydride-based hydrogen storage system and considers various potential methods to reduce the on-board cooling load by increasing reactor pressure and decreasing fuel cell pressure.Copyright © 2005 by ASME
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Heat of Reaction Measurements of Sodium Borohydride Alcoholysis
Heat Transfer: Volume 4, 2005Co-Authors: Jinsong Zhang, T.s. Fisher, Jay P. Gore, P. Veeraraghavan RamachandranAbstract:On-board hydrogen storage has been identified as one of the most challenging technical barriers to the transition from gasoline to hydrogen powered vehicles. The Hydrogen-On-Demand™ system patented by Millenium Cell Inc. uses Sodium Borohydride and water to generate hydrogen when needed. The system has many advantages over other types of storage methods such as compressed hydrogen, liquid hydrogen and metal hydrides. Nevertheless, the cost of making and regenerating Sodium Borohydride is too high. A recently filed patent indicates that Sodium Borohydride alcoholysis (e.g. using ethylene glycol) may offer some advantages over the aqueous system in terms of regeneration, which may significantly reduce the cost to regenerate Sodium Borohydride. To begin evaluating the energy efficiency of this new approach, this work experimentally characterizes the heat of reaction of Sodium Borohydride with ethylene glycol. The heat of reaction was measured to be approximately 220 kJ/mol (exothermic). For the Sodium Borohydride and water reaction, two different heat of reaction values have been reported in prior literature. The present work shows that the heats of reaction for both Sodium Borohydride hydrolysis and alcoholysis are both near 220 kJ/mol exothermically.© 2005 ASME
