The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
D. Stolten - One of the best experts on this subject based on the ideXlab platform.
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Operating strategies for Fuel Processing Systems with a focus on water–gas shift reactor stability
Applied Energy, 2016Co-Authors: Daniel Krekel, Remzi Can Samsun, Joachim Pasel, Matthias Prawitz, Ralf Peters, D. StoltenAbstract:Abstract This contribution deals with the development of suitable operating strategies for diesel/kerosene-Fueled Fuel cell APUs. The focus is on the autothermal reformer (ATR) and the water–gas shift (WGS) reactor. In the first part shutdown experiments under high-temperature shift (HTS) conditions were used to identify the possible detrimental effect of higher hydrocarbons on the activity and stability of two commercial WGS catalysts. The results indicated that 220 ppmv higher hydrocarbons had no negative effect on the catalyst activity/stability. The second part presents Fuel Processing System experiments, which revealed much higher concentrations of higher hydrocarbons during transients like startup/shutdown than the concentrations investigated in the first part. Through the development of new startup/shutdown strategies concentrations of higher hydrocarbons were lowered by a factor of up to 10 for startup and of up to 400 for shutdown. The results were reproduced using four different diesel and kerosene Fuels. The newly developed strategies improve Fuel conversion in the reformer and may possibly prevent catalyst deactivation in the water–gas shift reactor during transient conditions.
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Operational experience with the Fuel Processing System for Fuel cell drives
Journal of Power Sources, 2002Co-Authors: B. Emonts, T. Grube, B. Höhlein, R. Peters, H. Schmidt, D. Stolten, J. Bøgild Hansen, A. TschauderAbstract:Abstract Electric motor vehicle drive Systems with polymer electrolyte Fuel cells (PEFCs) for the conversion of chemical into electrical energy offer great advantages over internal combustion engines with respect to the emission of hydrocarbons, carbon monoxide and nitrogen oxides. Since the storage Systems available for hydrogen, the “Fuel” of the Fuel cell, are insufficient, it is meaningful to produce the hydrogen on board the vehicle from a liquid energy carrier, such as methanol. At the Research Center Julich such a drive System has been developed, which produces a hydrogen-rich gas from methanol and water, cleans this gas and converts it into electricity in a PEFC. This System and the operational experience on the basis of simulated and experimental results are presented here.
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Operational experience with the Fuel Processing System for Fuel cell drives
Journal of Power Sources, 2002Co-Authors: B. Emonts, J. Bøgild Hansen, T. Grube, B. Höhlein, R. Peters, H. Schmidt, D. Stolten, A. TschauderAbstract:Electric motor vehicle drive Systems with polymer electrolyte Fuel cells (PEFCs) for the conversion of chemical into electrical energy offer engines with respect to the emission of hydrocarbons, carbon monoxide and nitrogen oxides. Since great advantages over internal combustion the storage Systems available for hydrogen, the "Fuel" of the Fuel cell, are insufficient, it is meaningful to produce the hydrogen on board the vehicle from a liquid energy carrier, such as methanol. At the Research Center Julich such a drive System has been developed, which produces a hydrogen-rich gas from methanol and water, cleans this gas and converts it into electricity in a PEFC. This System and the operational experience on the basis of simulated and experimental results are presented here. (C) 2002 Elsevier Science B.V. All rights reserved
Wang Lai Yoon - One of the best experts on this subject based on the ideXlab platform.
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development of compact Fuel processor for 2 kw class residential pemfcs
Journal of Power Sources, 2006Co-Authors: Yutaek Seo, Jin Hyeok Jeong, Dong Joo Seo, Wang Lai YoonAbstract:Korea Institute of Energy Research (KIER) has been developing a novel Fuel Processing System to provide hydrogen rich gas to residential polymer electrolyte membrane Fuel cells (PEMFCs) cogeneration System. For the effective design of a compact hydrogen production System, the unit processes of steam reforming, high and low temperature water gas shift, steam generator and internal heat exchangers are thermally and physically integrated into a packaged hardware System. Several prototypes are under development and the prototype I Fuel processor showed thermal efficiency of 73% as a HHV basis with methane conversion of 81%. Recently tested prototype II has been shown the improved performance of thermal efficiency of 76% with methane conversion of 83%. In both prototypes, two-stage PrOx reactors reduce CO concentration less than 10 ppm, which is the prerequisite CO limit condition of product gas for the PEMFCs stack. After confirming the initial performance of prototype I Fuel processor, it is coupled with PEMFC single cell to test the durability and demonstrated that the Fuel processor is operated for 3 days successfully without any failure of Fuel cell voltage. Prototype II Fuel processor also showed stable performance during the durability test.
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Design of an integrated Fuel processor for residential PEMFCs applications
Journal of Power Sources, 2006Co-Authors: Jin Hyeok Jeong, Wang Lai YoonAbstract:KIER has been developing a novel Fuel Processing System to provide hydrogen rich gas to residential PEMFCs System. For the effective design of a compact hydrogen production System, each unit process for steam reforming and water gas shift, has a steam generator and internal heat exchangers which are thermally and physically integrated into a single packaged hardware System. The newly designed Fuel processor (prototype II) showed a thermal efficiency of 78% as a HHV basis with methane conversion of 89%. The preferential oxidation unit with two staged cascade reactors, reduces, the CO concentration to below 10 ppm without complicated temperature control hardware, which is the prerequisite CO limit for the PEMFC stack. After we achieve the initial performance of the Fuel processor, partial load operation was carried out to test the performance and reliability of the Fuel processor at various loads. The stability of the Fuel processor was also demonstrated for three successive days with a stable composition of product gas and thermal efficiency. The CO concentration remained below 10 ppm during the test period and confirmed the stable performance of the two-stage PrOx reactors.
Robert S Wegeng - One of the best experts on this subject based on the ideXlab platform.
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microchannel reactors for Fuel Processing applications i water gas shift reactor
Chemical Engineering Science, 1999Co-Authors: A Y Tonkovich, Jennifer L Zilka, Mike Lamont, Yong Wang, Robert S WegengAbstract:Abstract The water gas shift reactor is one of the critical components of a multi-reactor Fuel Processing System that supports distributed energy production through the use of a Fuel cell. The water gas shift reaction converts carbon monoxide (produced in the primary conversion stage of the Fuel processor) and water to carbon dioxide and hydrogen. The water gas shift reaction has slow observed kinetics, with multiple-second contact times, which are cited in fixed-bed reactors. The intrinsic reaction kinetics, however, are measured to be fast, with millisecond contact times, which enables miniaturized deployment in a microchannel reactor. Microchannel reactors reduce heat and mass transport limitations for reactions, and thus facilitate exploiting fast intrinsic reaction kinetics, ie. high effectiveness factors. The implications of this work suggest that a water gas shift reactor for a Fuel processor (and other applications) will approach sizes one-to-two orders of magnitude smaller than conventional Processing hardware.
Kyoungdoug Min - One of the best experts on this subject based on the ideXlab platform.
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Dynamic modeling of a high-temperature proton exchange membrane Fuel cell with a Fuel processor
International Journal of Hydrogen Energy, 2014Co-Authors: Jaeman Park, Kyoungdoug MinAbstract:Abstract A dynamic model of a high-temperature proton exchange membrane Fuel cell with a Fuel processor is developed in this study. In the model, a Fuel Processing System, a Fuel cell stack, and an exhaust gas burner are modeled and integrated. The model can predict the characteristics of the overall System and each component at the steady and transient states. Specifically, a unit Fuel cell model is discretized in a simplified quasi-three-dimensional geometry; therefore, the model can rapidly predict the distribution of Fuel cell characteristics. Various operating conditions such as the steam-to-carbon ratio, oxygen-to-carbon ratio, and autothermal reforming inlet temperature are varied and investigated in this study. In addition, the dynamic characteristics exhibited during the transient state are investigated, and an efficiency controller is developed and implemented in the model to maintain the electrical efficiency. The simulation results demonstrate that the steam-to-carbon ratio and the oxygen-to-carbon ratio affect the electrical and System efficiency and that controlling the Fuel flow rate maintains the electrical efficiency in the transient state. The model may be a useful tool for investigating the characteristics of the overall System as well as for developing optimal control strategies for enhancing the System performance.
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Dynamic Simulation of a Stationary PEM Fuel Cell System
ASME 2006 Fourth International Conference on Fuel Cell Science Engineering and Technology Parts A and B, 2006Co-Authors: Kyoungdoug Min, Jack Brouwer, John Auckland, Fabian Mueller, Scott SamuelsenAbstract:A dynamic model of a stationary PEM Fuel cell System has been developed in Matlab-Simulink®. The System model accounts for the Fuel Processing System, PEM stack with coolant, humidifier with anode tail-gas oxidizer (ATO), and an enthalpy wheel for cathode air. For the Fuel Processing System four reactors were modeled: (1) an auto thermal reactor (ATR) (2) a high temperature shift (HTS) reactor, (3) a low temperature shift (LTS) reactor, and (4) a preferential oxidation (PROX) reactor. Chemical kinetics for ATR that describe steam reformation of methane and partial oxidation of methane were simultaneously solved to accurately predict the reaction dynamics. Chemical equilibrium of CO with H2 O was assumed at HTS and LTS reactor exits to calculate CO conversion corresponding to the temperature of each reactor. A quasi-two dimensional unit PEM cell was modeled with five control volumes for solving the dynamic species and mass conservation equations and seven control volumes to solve the dynamic energy balance and to capture the details of MEA behavior, such as water transport, which is critical to accurately determine polarization losses. The dynamic conservation equations, primary heat transfer equations and equations of state are solved in each bulk component and each component is linked together to represent the complete System. A comparison of steady-state model results to experimental data shows that the System model well predicts the actual System power and catalytic partial oxidation (CPO) temperature. Transient simulation of DC power is also well matched with the experimental results to within a few percent. The model predictions well characterized the observed dynamic CPO temperature, voltage, and temperature of stack coolant outlet observations that are representative of a generic PEM stationary Fuel cell System performance. The model is shown to be a useful tool for investigating the effects of inlet conditions and for the development of control strategies for enhancing System performance.Copyright © 2006 by ASME
Takumi Hayashi - One of the best experts on this subject based on the ideXlab platform.
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Progress of fusion Fuel Processing System development at the Japan Atomic Energy Research Institute
Fusion Engineering and Design, 2000Co-Authors: Masataka Nishi, Toshihiko Yamanishi, Yoshinori Kawamura, Yasunori Iwai, Takumi Hayashi, K. Isobe, S. O'hira, Hirofumi Nakamura, Kazuhiro Kobayashi, T. SuzukiAbstract:The Tritium Process Laboratory (TPL) at the Japan Atomic Energy Research Institute has been working on the development of Fuel Processing technology for fusion reactors as a major activity. A fusion Fuel Processing loop was installed and is being tested with tritium under reactor relevant conditions. The loop at the TPL consists of ZrCo based tritium storage beds, a plasma exhaust Processing System using a palladium diffuser and an electrolytic reactor, cryogenic distillation columns for isotope separation, and analytical Systems based on newly developed micro gas chromatographs and Raman Spectroscopy. Several extended demonstration campaigns were performed under realistic reactor conditions to test tritiated impurity Processing. A sophisticated control technique of distillation column was performed at the same time, and integrated Fuel circulation was successfully demonstrated. Major recent design work on the International Thermonuclear Experimental Reactor (ITER) tritium plant at the TPL is devoted to water detritiation based on liquid phase catalytic exchange for improved tritium removal from waste water.
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Development of a tritium Fuel Processing System using an electrolytic reactor for ITER
Nuclear Fusion, 2000Co-Authors: Toshihiko Yamanishi, S. Konishi, Yoshinori Kawamura, Yasunori Iwai, T. Arita, T. Maruyama, T. Kakuta, Mikio Enoeda, S. Ohira, Takumi HayashiAbstract:A System composed of a palladium diffuser and an electrolytic reactor has been proposed and then developed for the Fuel cleanup System of ITER. The performance of the System has been studied in detail in a stand-alone test. A Fuel simulation loop of ITER was constructed by connecting the Fuel cleanup and hydrogen isotope separation Systems developed; and the function of each System in the loop has been demonstrated. For tritium recovery from the exhaust gas during helium glow discharge cleaning of the vacuum chamber of ITER, a cryogenic molecular sieve bed System has been proposed and demonstrated.
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Operation of a simulated non-steady tokamak Fuel loop using the tritium Systems test assembly
Fusion Engineering and Design, 1995Co-Authors: S. Konishi, Mikio Enoeda, Takumi Hayashi, S. O'hira, T. Suzuki, Y Yamanishi, M. Yamada, Kiyoshi Okuno, R. H. Sherman, R.s. WillmsAbstract:Abstract In order to develop a Fuel System for a realistic fusion device in near future, a number of experimental campaigns of a simulated fusion Fuel loop were performed under practical non-steady conditions at the Tritium Systems Test Assembly (TSTA). Some technical issues specific for non-steady Fuel loop were identified and are being investigated further. The overall process loop was operated with non-steady inputs to better interface with pulsed tokamak operation, which requires a rather different and improved Processing capability specific to each subSystem. The cryogenic distillation columns in the isotope separation are modified to provide side-stream recycle paths with isotopic equilibration function. This change improved separation characteristics with various feed compositions, and reduces the required number of columns for Processing and resulted in a reduced tritium inventory in the isotope separation System (ISS). Another major technical development on the ISS is addition of a number of feed-back control loops that automatically operate the distillation columns stably under changing feed conditions. The plasma exhaust Processing System composed of palladium diffuser, catalytic reactor, electrolysis cell and cold trap was operated mainly in the batch mode to handle a broader range of input flow rate and composition in various configurations to minimize tritium loss and inventory. The results demonstrated the overall capability and flexibility of the TSTA loop to serve as a Fuel Processing System under non-steady conditions; however, they imply that many technical issues arise in operating a practical Fuel Processing System. These may not be foreseen in the design stage and can only be determined during integrated tests under realistic operating conditions.
