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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean hydrogen and new energy society
Journal Basic Information
Journal DOI :
The Korean Hydrogen and New Energy Society
Editor in Chief :
Volume & Issues
Volume 24, Issue 6 - Dec 2013
Volume 24, Issue 5 - Oct 2013
Volume 24, Issue 4 - Aug 2013
Volume 24, Issue 3 - Jun 2013
Volume 24, Issue 2 - Apr 2013
Volume 24, Issue 1 - Feb 2013
Selecting the target year
A Study on Preferential CO Oxidation over Supported Pt Catalysts to Produce High Purity Hydrogen
Jeon, Kyung-Won ; Jeong, Dae-Woon ; Jang, Won-Jun ; Na, Hyun-Suk ; Roh, Hyun-Seog ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 5, 2013, Pages 353~358
DOI : 10.7316/KHNES.2013.24.5.353
To develop preferential CO oxidation reaction (PROX) catalyst for small scale hydrogen generation system, supported Pt catalysts have been applied for the target reaction. The supports were systematically changed to optimize supported Pt catalysts.
catalyst showed the highest CO conversion among the catalysts tested in this study. This is due to easier reducibility, the highest dispersion, and smallest particle diameter of
. It has been found that the catalytic performance of supported Pt catalysts for PROX depends strongly on the reduction property and depends partly on the Pt dispersion of supported Pt catalysts. Thus,
can be a promising catalyst for PROX for small scale hydrogen generation system.
A Study on Characteristics of HI Decomposition Using Pt Catalysts on ZrO
Ko, Yunki ; Park, Eunjung ; Bae, Kikwang ; Park, Chusik ; Kang, Kyoungsoo ; Cho, Wonchul ; Jeong, Seonguk ; Kim, Changhee ; Kim, Young Ho ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 5, 2013, Pages 359~366
DOI : 10.7316/KHNES.2013.24.5.359
This work is investigated for the catalytic decomposition of hydrogen iodide (HI). Platinum was used as active material by loading on
mixed oxide in HI decomposition reaction. To obtain high and stable conversion of hydrogen iodide in severe condition, it was required to improve catalytic activity. For this reason, a method increasing dispersion of platinum was proposed in this study. In order to get high dispersion of platinum, zirconia was incorporated in silica by sol-gel synthesis. Incorporating zirconia influence increasing platinum dispersion and BET surface area as well as decreasing deactivation of catalysts. It should be able to stably product hydrogen for a long time because of inhibitive deactivation. HI decomposition reaction was carried out under the condition of
and 1 atm in a fixed bed reactor. Catalysts analysis methods such as
adsorption/desorption analysis, X-ray diffraction, X-ray fluorescence, ICP-AES and CO gas chemisorption were used to measurement of their physico-chemical properties.
Effect of Melt-Spinning Process on Hydrogen Storage Properties of Mass-Produced Ti
Kim, Jinho ; Han, Kyusung ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 5, 2013, Pages 367~372
DOI : 10.7316/KHNES.2013.24.5.367
Hydrogen storage as a metal hydride is the most promising alternative because of its relatively large hydrogen storage capacities near room temperature. TiMn2-based C14 Laves phases alloys are one of the promising hydrogen storage materials with easy activation, good hydriding-dehydriding kinetics, high hydrogen storage capacity and relatively low cost. In this work, multi-component, hyper-stoichiometric
C14 Laves phase alloys were prepared by a vacuum induction melting for a hydrogen storage tank. Since pure vanadium (V) is quite expensive, the substitution of the V element in these alloys has been tried and some interesting results were achieved by replacing V by commercial ferrovanadium (FeV) raw material. In addition, the melt-spinning process, which was applied to the manufacturing of some of these alloys, could make the plateau slopes much flatter, which resulted in the increase of reversible hydrogen storage capacity. The improvement of sloping properties of melt-spun
alloys was mainly attributed to the homogeneity of chemical composition.
Operational Optimization of Anodic/cathodic Utilization for a Residential Power Generation System to Improve System Power Efficiency
Seok, Donghun ; Kim, Minjin ; Sohn, Young-Jun ; Lee, Jinho ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 5, 2013, Pages 373~385
DOI : 10.7316/KHNES.2013.24.5.373
To obtain higher power efficiency of Residential Power Generation system(RPG), it is needed to operate system on optimized stoichiometric ratios of fuel and air. Stoichiometric ratios of fuel/air are closely related to efficiency of stack, reformer and power consumption of Balance Of Plant(BOP). In this paper, optimizing stoichiometric ratios of fuel/air are conducted through systematic experiments and modeling. Based on fundamental principles and experimental data, constraints are chosen. By implementing these optimum values of stoichiometric ratios, power efficiency of the system could be maximized.
Optimal Sizing of the Manifolds in a PEM Fuel Cell Stack using Three-Dimensional CFD Simulations
Jeong, Jeehoon ; Han, In-Su ; Shin, Hyun Khil ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 5, 2013, Pages 386~392
DOI : 10.7316/KHNES.2013.24.5.386
Polymer electrolyte membrane (PEM) fuel cell stacks are constructed by stacking several to hundreds of unit cells depending on their power outputs required. Fuel and oxidant are distributed to each cell of a stack through so-called manifolds during its operation. In designing a stack, if the manifold sizes are too small, the fuel and oxidant would be maldistributed among the cells. On the contrary, the volume of the stack would be too large if the manifolds are oversized. In this study, we present a three-dimensional computational fluid dynamics (CFD) model with a geometrically simplified flow-field to optimize the size of the manifolds of a stack. The flow-field of the stack was simplified as a straight channel filled with porous media to reduce the number of computational meshes required for CFD simulations. Using the CFD model, we determined the size of the oxidant manifold of a 30 kW-class PEM fuel cell stack that comprises 99 cells. The stack with the optimal manifold size showed a quite uniform distribution of the cell voltages across the entire cells.
A Study on the Analysis of the Performance and Efficiency of a Low-pressure Operating PEMFC System for Vehicle Applications Using MATLAB/Simulink
Park, Raehyeok ; Kim, Han-Sang ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 5, 2013, Pages 393~400
DOI : 10.7316/KHNES.2013.24.5.393
The air supply system has a significant effect on the efficiency of polymer electrolyte membrane fuel cell (PEMFC) systems. The performance and efficiency of automotive PEMFC systems are greatly influenced by their air supply system configurations. This study deals with the system simulation of automotive PEMFC systems using MATLAB/Simulink framework. In this study, a low-pressure operating PEMFC system adopting blower sub-module (turbo-blower) is modeled to investigate the effects of stack operating temperature and air stoichiometry on the parasitic power and efficiency of automotive PEMFC systems. In addition, the PEMFC net system efficiency and parasitic power of air supply system are mainly compared for the two types (low-pressure operating and high-pressure operating) of automotive PEMFC systems under the same net power conditions. It is suggested that the obtained results from this system approach can be applied for establishing the novel operating strategies for FC vehicles.
A Simulation Study of the Effect of Microstructural Design on the Performance of Solid Oxide Fuel Cells With Direct Internal Reforming
Sohn, Sangho ; Nam, In Hyun ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 5, 2013, Pages 401~412
DOI : 10.7316/KHNES.2013.24.5.401
The paper is to study on the simulation of the micro/macroscale thermo-electrochemical model of a single cell of anode-supported SOFC with direct internal reforming. The coupled heat and mass transport, electrochemical and reforming reactions, and fluid flow were simultaneously simulated based on mass, energy, charge conservation. The micro/macroscale model first calculates the detailed electrochemical and direct internal reforming processes in porous electrodes based on the comprehensive microscale model and then solve the macroscale processes such as heat and mass transport, and fluid flow in SOFCs with assumption of fully-developed flow in gas channel. The simulation results evaluate the overall performance by analyzing distributions of mole fraction, current density, temperature and microstructural design in co/counter flow configurations.
A Study on Effect of Thermal Decomposition Products of Coal on Anodic Reactions in Direct Carbon Fuel Cell
Rhie, Young Hoon ; Eom, Seong Yong ; Ahn, Seong Yool ; Choi, Gyung Min ; Kim, Duck Jool ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 5, 2013, Pages 413~420
DOI : 10.7316/KHNES.2013.24.5.413
Effect of inherent volatile matters in fuels on electrochemical reactions of anode was investigated for a single direct carbon fuel cell (DCFC). Raw coals used as power source in the DCFC release light gases into the atmosphere under the operating temperature of DCFC (
) by thermal decomposition and only char remained. These exhausted gases change the gas composition around anode and affect the electrochemical oxidation reaction of system. To investigate the effect of produced gases, comparative study was conducted between Indonesian sub-bituminous coal and its char obtained through thermal treatment, carbonizing. Maximum power density of raw coal (
) was appeared higher than that of char (
) because the gases produced from the raw coal during thermal decomposition gave additional positive results to electrochemical reaction of the system. The produced gases from coals were analyzed using TGA and FT-IR. The influence of volatile matters on anodic electrolyteelectrode interface was observed by the equivalent circuit induced from fitting of impedance spectroscopy data.
Time Dependent Degradation of Cell in Dye-Sensitized Solar Cell
Seo, Hyun Woo ; Kim, Ki Soo ; Beak, Hyun Duk ; Kim, Dong Min ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 5, 2013, Pages 421~427
DOI : 10.7316/KHNES.2013.24.5.421
We report on the time dependent degradation of cell in dye-sensitized solar cells (DSSC). The photovoltaic performance of DSSC over a period of time was investigated in liquid electrolyte based on triiodide/iodide during six days. It was found that the short circuit current density (
) of the cell dropped from 9.9 to
while efficiency (
) of the cell decreased from 4.4 to 3.3%. The parameters corresponding to fundamental electronic and ionic processes in a working DSSC are determined from the electrochemical impedance spectrascopy (EIS) at open-circuit potential (
). EIS study of the DSSC in the this work showed that the electron life time
and chemical capacitance
decreased significantly after six days. It was correlated the
and efficiency decreased after six days.
The Characteristics of Attrition of Absorbents for Pre-combustion CO
Ryu, Hojung ; Lee, Dongho ; Moon, Jongho ; Park, Youngcheol ; Jo, Sungho ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 5, 2013, Pages 428~436
DOI : 10.7316/KHNES.2013.24.5.428
Attrition characteristics of
absorbents for pre-combustion
capture were investigated to check attrition loss of those absorbents and to determine solid circulation direction and the better
absorbent. The cumulative attrition losses of two absorbents increased with increasing time. However, attrition loss under a humidified condition was lower than that under a non-humidified condition case. Between two absorbents, attrition loss of PKM1-SU absorbent was higher than that of P4-600 absorbent. The average particle sizes of the attrited particles were less than
for two absorbents under a non-humidified condition case, and therefore, we could conclude that the main mechanism of attrition for two absorbents is not fragmentation but abrasion. Based on the results from the test for the effect of humidity on the attrition loss, we selected solid circulation direction from SEWGS reactor to regeneration reactor because the SEWGS reactor contains more water vapor than regeneration reactor. Attrition loss and make-up rate of two absorbents were compared based on the results from
sorption capacity tests and attrition tests. Required make-up rate of P4-600 absorbent was lower than that of PKM1-SU absorbent. However, more detail investigation on the optimum regeneration temperature, manufacturing cost, solid circulation rate, regeneration rate, and long-term sorption capacity should be considered to select the best
Spectroscopic Analysis on Hydroquinone Clathrates for an Application to Storage/Recovery of Olefin Compounds
Lee, Jong-Won ; Pratik, Dotel ; Kang, Seong-Pil ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 5, 2013, Pages 437~443
DOI : 10.7316/KHNES.2013.24.5.437
Clathrate samples, using hydroquinone as a host and ethylene or propylene as a possible guest, were prepared and analyzed by means of spectroscopic measurements. Obtained results showed that ethylene can form clathrate compounds with hydroquinone at 4.0MPa and room temperature, while propylene cannot form clathrate compounds. Different formation behaviors of these two olefin compounds can be applied to a clathrate-based storage/recovery of ethylene in a selective way, and can provide useful information on the cavity size of the formed clathrate compounds.
Effects of the Internal Structure on the Distribution Performance of a Refrigerant Distributor
Kim, Dong-Hwi ; Sa, Yong-Gheol ; Chung, Baikyoung ; Park, Byung-Duck ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 5, 2013, Pages 444~450
DOI : 10.7316/KHNES.2013.24.5.444
The distribution performance of refrigerant distributors in air conditioner evaporators was examined numerically and experimentally. Internal flow analysis of the distributor by CFD found that the distance from the socket to the cone, the angle of the cone and the base area of the cone were the most important factors affecting refrigerant distribution ability and vortex creation. To enhance distribution performance, two distributors with improved internal structures were designed. To test these new structures, distribution performance was also analyzed by CFD and an empirical experiment was carried out using the water-nitrogen. Experimental results on the distribution fraction of each distributor hole showed a good agreement with the results of the CFD analysis. Thus, the new design of the distributors enhanced distribution performance of the refrigerant distributors.
Evaluation on Light Scattering Behavior of a Pulverized Coal Suspension
Hwang, Munkyeong ; Nam, Hyunsoo ; Kim, Kyubo ; Song, Juhun ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 5, 2013, Pages 451~460
DOI : 10.7316/KHNES.2013.24.5.451
In a direct coal fuel cell (DCFC) system, it is essential to identify volume fraction of coal suspended in electrolyte melt in order to control its dispersion and fluidity. This requirement is compelling especially at anode channel where hot slurry is likely to flow at low velocity. In this study, light scattering techniques were employed to measure the volume fraction for a pulverized coal suspension with relatively high absorption coefficient. The particle size, scattering angle, and volume fraction were varied to evaluate their effects on the scattering behavior as well as scattering regime. The larger coal size and smaller forward scattering angle could provide a shift to more favorable scattering regime, i.e., independent scattering, where interferences of light scattering from one particle with others are suppressed.
A Composition and Basis Experiment of Single Cylinder Low Speed Diesel Engine for Atkinson Cycle Materialization
Jang, Jtaeik ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 5, 2013, Pages 461~466
DOI : 10.7316/KHNES.2013.24.5.461
In this research, the diesel cycle was thermodynamically interpreted to evaluate the possibility of high efficiency by converting diesel engine to the atkinson cycle, and general cycle features were analyzed after comparing these two cycles. That an experimental single cylinder and a long stroke diesel-atkinson engine, of which S/B ratio was more than 3, were manufactured. After evaluating the engine through basic experiments, a diesel engine was converted into the atkinson cycle by constituent VCR (variable compression ratio) device and VVT (variable valve timing) system. The experimental method was to observe compression work reduction effects due to low compression effects from delayed intake valve closing of the early stage atkinson engine. The result, the possibility of increasing compression ratio about each engine load was confirmation by constructing compensate expansion-compression ratio in accordance with the delayed intake valve close.