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Sample records for fuel cells operational

  1. Fuel cells: Operating flexibly

    NASA Astrophysics Data System (ADS)

    Lee, Young Moo

    2016-09-01

    Fuel cells typically function well only in rather limited temperature and humidity ranges. Now, a proton exchange membrane consisting of ion pair complexes is shown to enable improved fuel cell performance under a wide range of conditions that are unattainable with conventional approaches.

  2. Molten Carbonate Fuel Cell Operation With Dual Fuel Flexibility

    DTIC Science & Technology

    2007-10-01

    electrolyte membrane fuel cell ( PEMFC ). At the higher operating temperature, fuel reforming of natural gas can occur internally, eliminating the need...oxygen PAFC Phosphoric Acid Fuel Cell PEMFC Polymer Electrolyte Membrane Fuel Cell PDS Propane Desulfurization System ppm parts per million psig

  3. Operating a fuel cell using landfill gas

    SciTech Connect

    Trippel, C.E.; Preston, J.L.; Trocciola, J.C.; Spiegel, R.J.

    1996-12-31

    The paper discusses operating a 200-kW phosphoric acid fuel cell using landfill gas (LFG) in Groton, Connecticut. The project is intended to demonstrate the viability of installing, operating, and maintaining a fuel cell operating on LFG at a landfill site. The goals of the project are to evaluate the fuel cell and gas pretreatment unit (GPU) operation, test modifications to simplify the design, and demonstrate the reliability of the system. The operation of the fuel cell on LFG presents an opportunity to use a waste gas that is harmful to the environment to generate electricity more cleanly and efficiently than other methods currently used.

  4. Operating a fuel cell using landfill gas

    SciTech Connect

    Trippel, C.E.; Preston, J.L. Jr.; Trocciola, J.; Spiegel, R.

    1996-12-31

    An ONSI PC25{trademark}, 200 kW (nominal capacity) phosphoric acid fuel cell operating on landfill gas is installed at the Town of Groton Flanders Road landfill in Groton, Connecticut. This joint project by the Connecticut Light & Power Company (CL&P) which is an operating company of Northeast Utilities, the Town of Groton, International Fuel Cells (IFC), and the US EPA is intended to demonstrate the viability of installing, operating and maintaining a fuel cell operating on landfill gas at a landfill site. The goals of the project are to evaluate the fuel cell and gas pretreatment unit operation, test modifications to simplify the GPU design and demonstrate reliability of the entire system.

  5. Fuel cell technology for lunar surface operations

    NASA Astrophysics Data System (ADS)

    Deronck, Henry J.

    1992-02-01

    Hydrogen-oxygen fuel cells have been shown, in several NASA and contractor studies, to be an enabling technology for providing electrical power for lunar bases, outposts, and vehicles. The fuel cell, in conjunction with similar electrolysis cells, comprises a closed regenerative energy storage system, commonly referred to as a regenerative fuel cell (RFC). For stationary applications, energy densities of 1,000 watt-hours per kilograms an order of magnitude over the best rechargeable batteries, have been projected. In this RFC, the coupled fuel cell and electrolyzer act as an ultra-light battery. Electrical energy from solar arrays 'charges' the system by electrolyzing water into hydrogen and oxygen. When an electrical load is applied, the fuel cell reacts the hydrogen and oxygen to 'discharge' usable power. Several concepts for utilizing RFC's, with varying degrees of integration, have been proposed, including both primary and backup roles. For mobile power needs, such as rovers, an effective configuration may be to have only the fuel cell located on the vehicle, and to use a central electrolysis 'gas station'. Two fuel cell technologies are prime candidates for lunar power system concepts: alkaline electrolyte and proton exchange membrane. Alkaline fuel cells have been developed to a mature production power unit in NASA's Space Shuttle Orbiter. Recent advances in materials offer to significantly improve durability to the level needed for extended lunar operations. Proton exchange membrane fuel cells are receiving considerable support for hydrospace and terrestrial transportation applications. This technology promises durability, simplicity, and flexibility.

  6. Fuel cell technology for lunar surface operations

    NASA Technical Reports Server (NTRS)

    Deronck, Henry J.

    1992-01-01

    Hydrogen-oxygen fuel cells have been shown, in several NASA and contractor studies, to be an enabling technology for providing electrical power for lunar bases, outposts, and vehicles. The fuel cell, in conjunction with similar electrolysis cells, comprises a closed regenerative energy storage system, commonly referred to as a regenerative fuel cell (RFC). For stationary applications, energy densities of 1,000 watt-hours per kilograms an order of magnitude over the best rechargeable batteries, have been projected. In this RFC, the coupled fuel cell and electrolyzer act as an ultra-light battery. Electrical energy from solar arrays 'charges' the system by electrolyzing water into hydrogen and oxygen. When an electrical load is applied, the fuel cell reacts the hydrogen and oxygen to 'discharge' usable power. Several concepts for utilizing RFC's, with varying degrees of integration, have been proposed, including both primary and backup roles. For mobile power needs, such as rovers, an effective configuration may be to have only the fuel cell located on the vehicle, and to use a central electrolysis 'gas station'. Two fuel cell technologies are prime candidates for lunar power system concepts: alkaline electrolyte and proton exchange membrane. Alkaline fuel cells have been developed to a mature production power unit in NASA's Space Shuttle Orbiter. Recent advances in materials offer to significantly improve durability to the level needed for extended lunar operations. Proton exchange membrane fuel cells are receiving considerable support for hydrospace and terrestrial transportation applications. This technology promises durability, simplicity, and flexibility.

  7. Direct carbonate fuel cell power plant operating with logistic fuels

    SciTech Connect

    Abens, S.G.; Steinfeld, G.

    1997-12-31

    In response to the US Department of Defense need for power generators which operate with logistic fuels, Energy Research Corporation and its subcontractors, Haldor Topsoe and Fluor Daniel, have conducted design studies and subscale equipment tests toward the development of fuel cell power plants with multifuel capability. A principal objective of this work was the development of a fixed-base carbonate fuel cell power plant design which can utilize both natural gas and military logistic fuels DF-2 and JP-8. To verify ERC`s technical approach, a 32 kW brassboard logistic fuel preprocessing system was assembled and operated with a Direct Carbonate Fuel Cell (DFC) stack. The project was conducted as part of DARPA`s Fuel Cell Power Plant Initiative Program for the development of dual use fuel cell power plants. The logistic fuel preprocessor consisted of a hydrodesulfurization plant which supplied desulfurized feed to an adiabatic prereformer. The methane-rich product gas provides fuel cell performance similar to that with natural gas. A preliminary design of a 3MW multifuel power plant prepared with input from the 32kW brassboard test confirmed that the thermal efficiency of a DFC power plant is nearly as high with logistic fuel (57%) as it is with natural gas (58%).

  8. Self-humidified proton exchange membrane fuel cells: Operation of larger cells and fuel cell stacks

    SciTech Connect

    Dhar, H.P.; Lee, J.H.; Lewinski, K.A.

    1996-12-31

    The PEM fuel cell is promising as the power source for use in mobile and stationary applications primarily because of its high power density, all solid components, and simplicity of operation. For wide acceptability of this power source, its cost has to be competitive with the presently available energy sources. The fuel cell requires continuous humidification during operation as a power source. The humidification unit however, increases fuel cell volume, weight, and therefore decreases its overall power density. Great advantages in terms of further fuel cell simplification can be achieved if the humidification process can be eliminated or minimized. In addition, cost reductions are associated with the case of manufacturing and operation. At BCS Technology we have developed a technology of self-humidified operation of PEM fuel cells based on the mass balance of the reactants and products and the ability of membrane electrode assembly (MEA) to retain water necessary for humidification under the cell operating conditions. The reactants enter the fuel cell chambers without carrying any form of water, whether in liquid or vapor form. Basic principles of self-humidified operation of fuel cells as practiced by BCS Technology, Inc. have been presented previously in literature. Here, we report the operation of larger self-humidified single cells and fuel cell stacks. Fuel cells of areas Up to 100 cm{sup 2} have been operated. We also show the self-humidified operation of fuel cell stacks of 50 and 100 cm{sup 2} electrode areas.

  9. GRID INDEPENDENT FUEL CELL OPERATED SMART HOME

    SciTech Connect

    Dr. Mohammad S. Alam

    2003-12-07

    A fuel cell power plant, which utilizes a smart energy management and control (SEMaC) system, supplying the power need of laboratory based ''home'' has been purchased and installed. The ''home'' consists of two rooms, each approximately 250 sq. ft. Every appliance and power outlet is under the control of a host computer, running the SEMaC software package. It is possible to override the computer, in the event that an appliance or power outage is required. Detailed analysis and simulation of the fuel cell operated smart home has been performed. Two journal papers has been accepted for publication and another journal paper is under review. Three theses have been completed and three additional theses are in progress.

  10. Towards operating direct methanol fuel cells with highly concentrated fuel

    NASA Astrophysics Data System (ADS)

    Zhao, T. S.; Yang, W. W.; Chen, R.; Wu, Q. X.

    A significant advantage of direct methanol fuel cells (DMFCs) is the high specific energy of the liquid fuel, making it particularly suitable for portable and mobile applications. Nevertheless, conventional DMFCs have to be operated with excessively diluted methanol solutions to limit methanol crossover and the detrimental consequences. Operation with diluted methanol solutions significantly reduces the specific energy of the power pack and thereby prevents it from competing with advanced batteries. In view of this fact, there exists a need to improve conventional DMFC system designs, including membrane electrode assemblies and the subsystems for supplying/removing reactants/products, so that both the cell performance and the specific energy can be simultaneously maximized. This article provides a comprehensive review of past efforts on the optimization of DMFC systems that operate with concentrated methanol. Based on the discussion of the key issues associated with transport of the reactants/products, the strategies to manage the supply/removal of the reactants/products in DMFC operating with highly concentrated methanol are identified. With these strategies, the possible approaches to achieving the goal of concentrated fuel operation are then proposed. Past efforts in the management of the reactants/products for implementing each of the approaches are also summarized and reviewed.

  11. Marine Fuel Cell Technology Verification Trainer Program: Operator Curriculum Development

    DTIC Science & Technology

    2007-11-02

    ofinito acn. including suggestetns Ior reductng the burden, to Departnment of Defne, t . Washingtn Headquara Services., Diremtorte for information...materials, reference FuelCell Energy (FCE, the manufacturer) documentation are subject to change as the Direct Fuel Cell ( DFC ) SSFC plant technology matures...introduction to the Direct Fuel Cell Ship Service Fuel Cell ( DFC SSFC) for future operators. These modules would fill a 2- to 4- day lecture and

  12. Fuel cell power plant economic and operational considerations

    NASA Technical Reports Server (NTRS)

    Lance, J. R.

    1984-01-01

    Fuel cell power plants intended for electric utility and cogeneration applications are now in the design and construction stage. This paper describes economic and operational considerations being used in the development and design of plants utilizing air cooled phosphoric acid fuel cells. Fuel cell power plants have some unique characteristics relative to other types of power plants. As a result it was necessary to develop specific definitions of the fuel cell power plant characteristics in order to perform cost of electricity calculations. This paper describes these characteristics and describes the economic analyses used in the Westinghouse fuel cell power plant program.

  13. Solid Oxide Fuel Cells Operating on Alternative and Renewable Fuels

    SciTech Connect

    Wang, Xiaoxing; Quan, Wenying; Xiao, Jing; Peduzzi, Emanuela; Fujii, Mamoru; Sun, Funxia; Shalaby, Cigdem; Li, Yan; Xie, Chao; Ma, Xiaoliang; Johnson, David; Lee, Jeong; Fedkin, Mark; LaBarbera, Mark; Das, Debanjan; Thompson, David; Lvov, Serguei; Song, Chunshan

    2014-09-30

    This DOE project at the Pennsylvania State University (Penn State) initially involved Siemens Energy, Inc. to (1) develop new fuel processing approaches for using selected alternative and renewable fuels – anaerobic digester gas (ADG) and commercial diesel fuel (with 15 ppm sulfur) – in solid oxide fuel cell (SOFC) power generation systems; and (2) conduct integrated fuel processor – SOFC system tests to evaluate the performance of the fuel processors and overall systems. Siemens Energy Inc. was to provide SOFC system to Penn State for testing. The Siemens work was carried out at Siemens Energy Inc. in Pittsburgh, PA. The unexpected restructuring in Siemens organization, however, led to the elimination of the Siemens Stationary Fuel Cell Division within the company. Unfortunately, this led to the Siemens subcontract with Penn State ending on September 23rd, 2010. SOFC system was never delivered to Penn State. With the assistance of NETL project manager, the Penn State team has since developed a collaborative research with Delphi as the new subcontractor and this work involved the testing of a stack of planar solid oxide fuel cells from Delphi.

  14. Method for operating a combustor in a fuel cell system

    DOEpatents

    Clingerman, Bruce J.; Mowery, Kenneth D.

    2002-01-01

    In one aspect, the invention provides a method of operating a combustor to heat a fuel processor to a desired temperature in a fuel cell system, wherein the fuel processor generates hydrogen (H.sub.2) from a hydrocarbon for reaction within a fuel cell to generate electricity. More particularly, the invention provides a method and select system design features which cooperate to provide a start up mode of operation and a smooth transition from start-up of the combustor and fuel processor to a running mode.

  15. Method for operating a combustor in a fuel cell system

    DOEpatents

    Chalfant, Robert W.; Clingerman, Bruce J.

    2002-01-01

    A method of operating a combustor to heat a fuel processor in a fuel cell system, in which the fuel processor generates a hydrogen-rich stream a portion of which is consumed in a fuel cell stack and a portion of which is discharged from the fuel cell stack and supplied to the combustor, and wherein first and second streams are supplied to the combustor, the first stream being a hydrocarbon fuel stream and the second stream consisting of said hydrogen-rich stream, the method comprising the steps of monitoring the temperature of the fuel processor; regulating the quantity of the first stream to the combustor according to the temperature of the fuel processor; and comparing said quantity of said first stream to a predetermined value or range of predetermined values.

  16. Fuel cell operation characterization using simulation

    NASA Astrophysics Data System (ADS)

    Schott, Pascal; Baurens, Pierre

    The first step of fuel cell stack characterization consists in experimental testing of its global electrochemical performances under various working conditions. The second step is devoted to link the collected data to local species concentrations, membrane hydration and resulting current density in the stack. In the project PICOS, we have to characterize a 1.5 kW 12-cells' stack of 330 cm 2. The stack performances are measured on a specific test bench and analyzed using a fuel cell-stack modeling tool. The test bench allows to control the oxygen (or air) and hydrogen flow rates and humidity at the inlet of the stack, the pressure at the outlet, and the delivered current. Each cell potential and the total stack potential are monitored, the produced water is condensed at the outlet in order to measure its amount. The model used is a mono-dimensional description of a single cell. It is based on a semi-empirical law for the local electrochemical response computation. The local pressures, temperatures, gas compositions and membrane hydration are computed dynamically. A semi-empirical electrochemical model of the active layer is fitted to experimental data, the gas diffusion layer porosity and electro-osmosis coefficient of the membrane have been adjusted to obtain the best fit. The simulations calculate the cell potential and the current density profile in the cell for various feeding conditions. The simulations allow us to explain the effect of gas hydration on the stack potential and to predict possible drying out of the membrane.

  17. Solid oxide fuel cell operable over wide temperature range

    DOEpatents

    Baozhen, Li; Ruka, Roswell J.; Singhal, Subhash C.

    2001-01-01

    Solid oxide fuel cells having improved low-temperature operation are disclosed. In one embodiment, an interfacial layer of terbia-stabilized zirconia is located between the air electrode and electrolyte of the solid oxide fuel cell. The interfacial layer provides a barrier which controls interaction between the air electrode and electrolyte. The interfacial layer also reduces polarization loss through the reduction of the air electrode/electrolyte interfacial electrical resistance. In another embodiment, the solid oxide fuel cell comprises a scandia-stabilized zirconia electrolyte having high electrical conductivity. The scandia-stabilized zirconia electrolyte may be provided as a very thin layer in order to reduce resistance. The scandia-stabilized electrolyte is preferably used in combination with the terbia-stabilized interfacial layer. The solid oxide fuel cells are operable over wider temperature ranges and wider temperature gradients in comparison with conventional fuel cells.

  18. Intelligent machine learning analysis for phosphoric acid fuel cell operations

    SciTech Connect

    Hoyt, W.; Foote, J.P.; Murphy, R.W.; Chen, F.C.

    1998-07-01

    Several fuel cell types are available and are in various stages of technology development. The complex nature of the balance of plant and fuel cell interface poses many technical challenges to achieve proper system control under commercial operating conditions. Real-time predictive diagnostic computer systems based on advanced intelligent machine learning technologies offer a means to facilitate the detection, understanding, and control of fuel cell subsystems to avoid system instabilities and failures that can result in costly plant shutdowns. The objectives reported herein are the development of physical and empirical computer models for application and testing of predictive control strategies based on intelligent machine learning techniques for fuel cells. A physical/empirical model was built and validated using available operating data from commercial fuel cells. Neural networks were then used to build an empirical model from the original physical/empirical model. Using the neural network model, a predictive, feedforward strategy was developed to control the fuel flow for a phosphoric acid fuel cell physical/empirical model. The predictive control strategy was compared to traditional proportional integral derivative control schemes.

  19. Methods for continuous direct carbon fuel cell operation with a circulating electrolyte slurry

    DOEpatents

    Harjes, Daniel I.; Dineen, Jr., D. Andrew; Guo, Liang; Calo, Joseph M.; Bloomfield, Valerie J.

    2017-02-07

    The present invention relates to methods and systems related to fuel cells, and in particular, to direct carbon fuel cells. The methods and systems relate to cleaning and removal of components utilized and produced during operation of the fuel cell, regeneration of components utilized during operation of the fuel cell, and generating power using the fuel cell.

  20. Intelligent Machine Learning Analysis for Fuel Cell Operations

    SciTech Connect

    Murphy, R W; Hoyt, W A

    2000-06-30

    A performance computational model for a 100 kW nominal solid oxide fuel cell generator system is described. The calculational methods are based on the FORTRAN programming language. Comprehensive parameter input options are presented, and constraints are identified. Example reactant, electrical, and efficiency outputs are demonstrated over the relevant operating ranges. A sample calculated output display at nominal operating conditions is given.

  1. FUEL CELL OPERATION ON LANDFILL GAS AT PENROSE POWER STATION

    EPA Science Inventory

    This demonstration test successfully demonstrated operation of a commercial phosphoric acid fuel cell (FC) on landfill gas (LG) at the Penrose Power Station in Sun Valley, CA. Demonstration output included operation up to 137 kW; 37.1% efficiency at 120 kW; exceptionally low sec...

  2. FUEL CELL OPERATION ON LANDFILL GAS AT PENROSE POWER STATION

    EPA Science Inventory

    This demonstration test successfully demonstrated operation of a commercial phosphoric acid fuel cell (FC) on landfill gas (LG) at the Penrose Power Station in Sun Valley, CA. Demonstration output included operation up to 137 kW; 37.1% efficiency at 120 kW; exceptionally low sec...

  3. System for controlling the operating temperature of a fuel cell

    DOEpatents

    Fabis, Thomas R.; Makiel, Joseph M.; Veyo, Stephen E.

    2006-06-06

    A method and system are provided for improved control of the operating temperature of a fuel cell (32) utilizing an improved temperature control system (30) that varies the flow rate of inlet air entering the fuel cell (32) in response to changes in the operating temperature of the fuel cell (32). Consistent with the invention an improved temperature control system (30) is provided that includes a controller (37) that receives an indication of the temperature of the inlet air from a temperature sensor (39) and varies the heat output by at least one heat source (34, 36) to maintain the temperature of the inlet air at a set-point T.sub.inset. The controller (37) also receives an indication of the operating temperature of the fuel cell (32) and varies the flow output by an adjustable air mover (33), within a predetermined range around a set-point F.sub.set, in order to maintain the operating temperature of the fuel cell (32) at a set-point T.sub.opset.

  4. Measurement of Species Distributions in Operating Fuel Cells

    SciTech Connect

    Partridge Jr, William P; Toops, Todd J; Parks, II, James E; Armstrong, Timothy R.

    2004-10-01

    Measurement and understanding of transient species distributions across and within fuel cells is a critical need for advancing fuel cell technology. The Spatially Resolved Capillary Inlet Mass Spectrometer (SpaciMS) instrument has been applied for in-situ measurement of transient species distributions within operating reactors; including diesel catalyst, air-exhaust mixing systems, and non-thermal plasma reactors. The work described here demonstrates the applicability of this tool to proton exchange membrane (PEM) and solid oxide fuel cells (SOFC) research. Specifically, we have demonstrated SpaciMS measurements of (1) transient species dynamics across a PEM fuel cell (FC) associated with load switching, (2) intra-PEM species distributions, and transient species dynamics at SOFC temperatures associated with FC load switching.

  5. Cerium migration during PEM fuel cell assembly and operation

    DOE PAGES

    Baker, Andrew M.; Torraco, Dennis; Judge, Elizabeth J.; ...

    2015-09-14

    Cerium migration between PEM fuel cell components is influenced by potential-driven mobility, ionic diffusion, and gradients in water content. These factors were investigated in ex situ experiments and in operating fuel cells. Potential-induced migration was measured ex situ in hydrated window cells. Cerium-containing MEAs were also fabricated and tested under ASTs. MEA disassembly and subsequent XRF analysis were used to observe rapid cerium migration during cell assembly and operation. During MEA hot pressing, humidification, and low RH operation at OCV, ionic diffusion causes uniform migration from the membrane into the catalyst layers. During high RH operation at OCV, in-plane ceriummore » gradients arise due to variations in water content. These gradients may diminish the scavenging efficacy of cerium by reducing its proximity to generated radicals.« less

  6. Cerium migration during PEM fuel cell assembly and operation

    SciTech Connect

    Baker, Andrew M.; Torraco, Dennis; Judge, Elizabeth J.; Spernjak, Dusan; Mukundan, Rangachary; Borup, Rod L.; Advani, Suresh G.; Prasad, Ajay K.

    2015-09-14

    Cerium migration between PEM fuel cell components is influenced by potential-driven mobility, ionic diffusion, and gradients in water content. These factors were investigated in ex situ experiments and in operating fuel cells. Potential-induced migration was measured ex situ in hydrated window cells. Cerium-containing MEAs were also fabricated and tested under ASTs. MEA disassembly and subsequent XRF analysis were used to observe rapid cerium migration during cell assembly and operation. During MEA hot pressing, humidification, and low RH operation at OCV, ionic diffusion causes uniform migration from the membrane into the catalyst layers. During high RH operation at OCV, in-plane cerium gradients arise due to variations in water content. These gradients may diminish the scavenging efficacy of cerium by reducing its proximity to generated radicals.

  7. Operation of polymer electrolyte membrane fuel cells with dry feeds: Design and operating strategies

    NASA Astrophysics Data System (ADS)

    Hogarth, Warren H. J.; Benziger, Jay B.

    The operation of polymer electrolyte membrane fuel cells (PEMFCs) with dry feeds has been examined with different fuel cell flow channel designs as functions of pressure, temperature and flow rate. Auto-humidified (or self-humidifying) PEMFC operation is improved at higher pressures and low gas velocities where axial dispersion enhances "back-mixing" of the product water with the dry feed. We demonstrate auto-humidified operation of the channel-less, self-draining fuel cell, based on a stirred tank reactor; data is presented showing auto-humidified operation from 25 to 115 °C at 1 and 3 atm. Design and operating requirements are derived for the auto-humidified operation of the channel-less, self-draining fuel cell. The auto-humidified self-draining fuel cell outperforms a fully humidified serpentine flow channel fuel cell at high current densities. The new design offers substantial benefits for simplicity of operation and control including: the ability to self-drain reducing flooding, the ability to uniformly disperse water removing current gradients and the ability to operate on dry feeds eliminating the need for humidifiers. Additionally, the design lends itself well to a modular design concept.

  8. Characteristics of Subfreezing Operation of Polymer Electrolyte Membrane Fuel Cells

    NASA Astrophysics Data System (ADS)

    Mishler, Jeffrey Harris

    Polymer Electrolyte Membrane (PEM) Fuel Cells are capable of high efficiency operation, and are free of NOx, SOx, and CO2 emissions when using hydrogen fuel, and ideally suited for use in transportation applications due to their high power density and low operating temperatures. However, under subfreezing conditions which may be encountered during winter seasons in some areas, product water will freeze within the membrane, cathode side catalyst layer and gas diffusion media, leading to voltage loss and operation failure. Experiments were undertaken in order to characterize the amount and location of water during fuel cell operation. First, in-situ neutron radiography was undertaken on the fuel cells at a normal operating temperature for various operating current densities, inlet relative humidities, and diffusion media hydrophobicities. It was found that more hydrophobic cathode microporous layer (MPL) or hydrophilic anode MPL may result in a larger amount of water transporting back to the anode. The water profiles along the channels were measured and the point of liquid water emergence, where two phase flow begins, was compared to previous models. Secondly, under subfreezing temperatures, neutron imaging showed that water ice product accumulates because of lack of a water removal mechanism. Water was observed under both the lands and channels, and increased almost linearly with time. It is found that most ice exists in the cathode side. With evidence from experimental observation, a cold start model was developed and explained, following existing approaches in the literature. Three stages of cold start are explained: membrane saturation, ice storage in catalyst layer pores, and then ice melting. The voltage losses due to temperature change, increased transport resistance, and reduced electrochemical surface area. The ionic conductivity of the membrane at subfreezing temperatures was modeled. Voltage evolution over time for isothermal cold starts was predicted and

  9. Challenges in microbial fuel cell development and operation.

    PubMed

    Kim, Byung Hong; Chang, In Seop; Gadd, Geoffrey M

    2007-09-01

    A microbial fuel cell (MFC) is a device that converts chemical energy into electricity through the catalytic activities of microorganisms. Although there is great potential of MFCs as an alternative energy source, novel wastewater treatment process, and biosensor for oxygen and pollutants, extensive optimization is required to exploit the maximum microbial potential. In this article, the main limiting factors of MFC operation are identified and suggestions are made to improve performance.

  10. System for operating solid oxide fuel cell generator on diesel fuel

    NASA Technical Reports Server (NTRS)

    Singh, Prabhu (Inventor); George, Raymond A. (Inventor)

    1997-01-01

    A system is provided for operating a solid oxide fuel cell generator on diesel fuel. The system includes a hydrodesulfurizer which reduces the sulfur content of commercial and military grade diesel fuel to an acceptable level. Hydrogen which has been previously separated from the process stream is mixed with diesel fuel at low pressure. The diesel/hydrogen mixture is then pressurized and introduced into the hydrodesulfurizer. The hydrodesulfurizer comprises a metal oxide such as ZnO which reacts with hydrogen sulfide in the presence of a metal catalyst to form a metal sulfide and water. After desulfurization, the diesel fuel is reformed and delivered to a hydrogen separator which removes most of the hydrogen from the reformed fuel prior to introduction into a solid oxide fuel cell generator. The separated hydrogen is then selectively delivered to the diesel/hydrogen mixer or to a hydrogen storage unit. The hydrogen storage unit preferably comprises a metal hydride which stores hydrogen in solid form at low pressure. Hydrogen may be discharged from the metal hydride to the diesel/hydrogen mixture at low pressure upon demand, particularly during start-up and shut-down of the system.

  11. Defining the Operational Conditions for High Temperature Polymer Fuel Cells in Naval Environments

    DTIC Science & Technology

    2008-12-31

    benefits of both Proton Exchange Membrane Fuel Cells ( PEMFCs ) and phosphoric acid fuel cell technologies: a solid polymer electrolyte, the PBI...membrane, but with higher temperature (160°C) operation. PBI membrane technology is far less developed than that for PEMFCs , but it is rapidly emerging as...how air contaminants affect the properties of proton exchange membrane fuel cells ( PEMFCs ). PEMFCs operate at 80 °C, and are the present choice of fuel

  12. Fuel cells: A survey

    NASA Technical Reports Server (NTRS)

    Crowe, B. J.

    1973-01-01

    A survey of fuel cell technology and applications is presented. The operating principles, performance capabilities, and limitations of fuel cells are discussed. Diagrams of fuel cell construction and operating characteristics are provided. Photographs of typical installations are included.

  13. OPERATION OF SOLID OXIDE FUEL CELL ANODES WITH PRACTICAL HYDROCARBON FUELS

    SciTech Connect

    Scott A. Barnett; Jiang Liu; Yuanbo Lin

    2004-07-30

    This work was carried out to achieve a better understanding of how SOFC anodes work with real fuels. The motivation was to improve the fuel flexibility of SOFC anodes, thereby allowing simplification and cost reduction of SOFC power plants. The work was based on prior results indicating that Ni-YSZ anode-supported SOFCs can be operated directly on methane and natural gas, while SOFCs with novel anode compositions can work with higher hydrocarbons. While these results were promising, more work was clearly needed to establish the feasibility of these direct-hydrocarbon SOFCs. Basic information on hydrocarbon-anode reactions should be broadly useful because reformate fuel gas can contain residual hydrocarbons, especially methane. In the Phase I project, we have studied the reaction mechanisms of various hydrocarbons--including methane, natural gas, and higher hydrocarbons--on two kinds of Ni-containing anodes: conventional Ni-YSZ anodes and a novel ceramic-based anode composition that avoid problems with coking. The effect of sulfur impurities was also studied. The program was aimed both at achieving an understanding of the interactions between real fuels and SOFC anodes, and providing enough information to establish the feasibility of operating SOFC stacks directly on hydrocarbon fuels. A combination of techniques was used to provide insight into the hydrocarbon reactions at these anodes during SOFC operation. Differentially-pumped mass spectrometry was be used for product-gas analysis both with and without cell operation. Impedance spectroscopy was used in order to understand electrochemical rate-limiting steps. Open-circuit voltages measurements under a range of conditions was used to help determine anode electrochemical reactions. Life tests over a wide range of conditions were used to establish the conditions for stable operation of anode-supported SOFC stacks directly on methane. Redox cycling was carried out on ceramic-based anodes. Tests on sulfur tolerance of

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Design and Operation of an Electrochemical Methanol Concentration Sensor for Direct Methanol Fuel Cell Systems

    NASA Technical Reports Server (NTRS)

    Narayanan, S. R.; Valdez, T. I.; Chun, W.

    2000-01-01

    The development of a 150-Watt packaged power source based on liquid feed direct methanol fuel cells is being pursued currently at the Jet propulsion Laboratory for defense applications. In our studies we find that the concentration of methanol in the fuel circulation loop affects the electrical performance and efficiency the direct methanol fuel cell systems significantly. The practical operation of direct methanol fuel cell systems, therefore, requires accurate monitoring and control of methanol concentration. The present paper reports on the principle and demonstration of an in-house developed electrochemical sensor suitable for direct methanol fuel cell systems.

  16. Design and Operation of an Electrochemical Methanol Concentration Sensor for Direct Methanol Fuel Cell Systems

    NASA Technical Reports Server (NTRS)

    Narayanan, S. R.; Valdez, T. I.; Chun, W.

    2000-01-01

    The development of a 150-Watt packaged power source based on liquid feed direct methanol fuel cells is being pursued currently at the Jet propulsion Laboratory for defense applications. In our studies we find that the concentration of methanol in the fuel circulation loop affects the electrical performance and efficiency the direct methanol fuel cell systems significantly. The practical operation of direct methanol fuel cell systems, therefore, requires accurate monitoring and control of methanol concentration. The present paper reports on the principle and demonstration of an in-house developed electrochemical sensor suitable for direct methanol fuel cell systems.

  17. TEST RESULTS FOR FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS

    EPA Science Inventory

    EPA, in conjunction with ONSI Corp., embarked on a project to define, design, test, and assess a fuel cell energy recovery system for application at anaerobic digester waste water (sewage) treatment plants. Anaerobic digester gas (ADG) is produced at these plants during the proce...

  18. TEST RESULTS FOR FUEL-CELL OPERATION ON LANDFILL GAS

    EPA Science Inventory

    Test results from a demonstration of fuel-cell (FC) energy recovery and control of landfill gas emissions are presented. The project addressed two major issues: (i) the design, construction, and testing of a landfill-gas cleanup system; and (ii) a field test of a commercial phos...

  19. TEST RESULTS FOR FUEL-CELL OPERATION ON LANDFILL GAS

    EPA Science Inventory

    Test results from a demonstration of fuel-cell (FC) energy recovery and control of landfill gas emissions are presented. The project addressed two major issues: (i) the design, construction, and testing of a landfill-gas cleanup system; and (ii) a field test of a commercial phos...

  20. TEST RESULTS FOR FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS

    EPA Science Inventory

    EPA, in conjunction with ONSI Corp., embarked on a project to define, design, test, and assess a fuel cell energy recovery system for application at anaerobic digester waste water (sewage) treatment plants. Anaerobic digester gas (ADG) is produced at these plants during the proce...

  1. Orbiter fuel cell performance constraints. STS/OPS Pratt Whitney fuel cells. Operating limits for mission planning

    NASA Technical Reports Server (NTRS)

    Kolkhorst, H. E.

    1980-01-01

    The orbiter fuel cell powerplant (FCP) performance constraints listed in the Shuttle Operational Data Book (SODB) were analyzed using the shuttle environmental control requirements evaluation tool. The effects of FCP lifetime, coolant loops, and FCP voltage output were considered. Results indicate that the FCP limits defined in the SODB are not valid.

  2. An operationally flexible fuel cell based on quaternary ammonium-biphosphate ion pairs

    DOE PAGES

    Lee, Kwan -Soo; Spendelow, Jacob Schatz; Choe, Yoong -Kee; ...

    2016-08-22

    Here, fuel cells are promising devices for clean power generation in a variety of economically and environmentally significant applications. Low-temperature proton exchange membrane (PEM) fuel cells utilizing Nafion require a high level of hydration, which limits the operating temperature to less than 100°C. In contrast, high-temperature PEM fuel cells utilizing phosphoric acid-doped polybenzimidazole can operate effectively up to 180°C; however, these devices degrade when exposed to water below 140°C. Here we present a different class of PEM fuel cells based on quaternary ammonium-biphosphate ion pairs that can operate under conditions unattainable with existing fuel cell technologies. These fuel cells exhibitmore » stable performance at 80–160°C with a conductivity decay rate more than three orders of magnitude lower than that of a commercial high-temperature PEM fuel cell. By increasing the operational flexibility, this class of fuel cell can simplify the requirements for heat and water management, and potentially reduce the costs associated with the existing fully functional fuel cell systems.« less

  3. An operationally flexible fuel cell based on quaternary ammonium-biphosphate ion pairs

    SciTech Connect

    Lee, Kwan -Soo; Spendelow, Jacob Schatz; Choe, Yoong -Kee; Fujimoto, Cy; Kim, Yu Seung

    2016-08-22

    Here, fuel cells are promising devices for clean power generation in a variety of economically and environmentally significant applications. Low-temperature proton exchange membrane (PEM) fuel cells utilizing Nafion require a high level of hydration, which limits the operating temperature to less than 100°C. In contrast, high-temperature PEM fuel cells utilizing phosphoric acid-doped polybenzimidazole can operate effectively up to 180°C; however, these devices degrade when exposed to water below 140°C. Here we present a different class of PEM fuel cells based on quaternary ammonium-biphosphate ion pairs that can operate under conditions unattainable with existing fuel cell technologies. These fuel cells exhibit stable performance at 80–160°C with a conductivity decay rate more than three orders of magnitude lower than that of a commercial high-temperature PEM fuel cell. By increasing the operational flexibility, this class of fuel cell can simplify the requirements for heat and water management, and potentially reduce the costs associated with the existing fully functional fuel cell systems.

  4. An operationally flexible fuel cell based on quaternary ammonium-biphosphate ion pairs

    SciTech Connect

    Lee, Kwan -Soo; Spendelow, Jacob Schatz; Choe, Yoong -Kee; Fujimoto, Cy; Kim, Yu Seung

    2016-08-22

    Here, fuel cells are promising devices for clean power generation in a variety of economically and environmentally significant applications. Low-temperature proton exchange membrane (PEM) fuel cells utilizing Nafion require a high level of hydration, which limits the operating temperature to less than 100°C. In contrast, high-temperature PEM fuel cells utilizing phosphoric acid-doped polybenzimidazole can operate effectively up to 180°C; however, these devices degrade when exposed to water below 140°C. Here we present a different class of PEM fuel cells based on quaternary ammonium-biphosphate ion pairs that can operate under conditions unattainable with existing fuel cell technologies. These fuel cells exhibit stable performance at 80–160°C with a conductivity decay rate more than three orders of magnitude lower than that of a commercial high-temperature PEM fuel cell. By increasing the operational flexibility, this class of fuel cell can simplify the requirements for heat and water management, and potentially reduce the costs associated with the existing fully functional fuel cell systems.

  5. An operationally flexible fuel cell based on quaternary ammonium-biphosphate ion pairs

    NASA Astrophysics Data System (ADS)

    Lee, Kwan-Soo; Spendelow, Jacob S.; Choe, Yoong-Kee; Fujimoto, Cy; Kim, Yu Seung

    2016-09-01

    Fuel cells are promising devices for clean power generation in a variety of economically and environmentally significant applications. Low-temperature proton exchange membrane (PEM) fuel cells utilizing Nafion require a high level of hydration, which limits the operating temperature to less than 100 ∘C. In contrast, high-temperature PEM fuel cells utilizing phosphoric acid-doped polybenzimidazole can operate effectively up to 180 ∘C however, these devices degrade when exposed to water below 140 ∘C. Here we present a different class of PEM fuel cells based on quaternary ammonium-biphosphate ion pairs that can operate under conditions unattainable with existing fuel cell technologies. These fuel cells exhibit stable performance at 80-160 ∘C with a conductivity decay rate more than three orders of magnitude lower than that of a commercial high-temperature PEM fuel cell. By increasing the operational flexibility, this class of fuel cell can simplify the requirements for heat and water management, and potentially reduce the costs associated with the existing fully functional fuel cell systems.

  6. Near-infrared imaging of water in a polymer electrolyte membrane during a fuel cell operation.

    PubMed

    Morita, Shigeaki; Jojima, Yuki; Miyata, Yasushi; Kitagawa, Kuniyuki

    2010-11-15

    A novel technique of spectroscopic imaging using a near-infrared (NIR) laser sheet beam was developed for visualization of liquid water in a proton-exchange membrane (PEM) sandwiched between two opaque electrodes set in a polymer electrolyte fuel cell (PEFC). In-plane two-dimensional distribution of water in the thin membrane was clearly visualized during the fuel cell operation. Under the condition of fuel feeding into the PEFC without humidification, water was generated by the fuel cell reaction in the whole electrode area. In contrast, under the condition of fuel feeding with humidification, the PEM got wet in the vicinity of a gas flow field locally.

  7. Performance Analysis of Air Breathing Proton Exchange Membrane Fuel Cell Stack (PEMFCS) At Different Operating Condition

    NASA Astrophysics Data System (ADS)

    Sunil, V.; Venkata siva, G.; Yoganjaneyulu, G.; Ravikumar, V. V.

    2017-08-01

    The answer for an emission free power source in future is in the form of fuel cells which combine hydrogen and oxygen producing electricity and a harmless by product-water. A proton exchange membrane (PEM) fuel cell is ideal for automotive applications. A single cell cannot supply the essential power for any application. Hence PEM fuel cell stacks are used. The effect of different operating parameters namely: type of convection, type of draught, hydrogen flow rate, hydrogen inlet pressure, ambient temperature and humidity, hydrogen humidity, cell orientation on the performance of air breathing PEM fuel cell stack was analyzed using a computerized fuel cell test station. Then, the fuel cell stack was subjected to different load conditions. It was found that the stack performs very poorly at full capacity (runs only for 30 min. but runs for 3 hours at 50% capacity). Hence, a detailed study was undertaken to maximize the duration of the stack’s performance at peak load.

  8. Fuel Cells

    ERIC Educational Resources Information Center

    Hawkins, M. D.

    1973-01-01

    Discusses the theories, construction, operation, types, and advantages of fuel cells developed by the American space programs. Indicates that the cell is an ideal small-scale power source characterized by its compactness, high efficiency, reliability, and freedom from polluting fumes. (CC)

  9. Fuel Cells

    ERIC Educational Resources Information Center

    Hawkins, M. D.

    1973-01-01

    Discusses the theories, construction, operation, types, and advantages of fuel cells developed by the American space programs. Indicates that the cell is an ideal small-scale power source characterized by its compactness, high efficiency, reliability, and freedom from polluting fumes. (CC)

  10. Magnetic resonance imaging of water content across the Nafion membrane in an operational PEM fuel cell

    NASA Astrophysics Data System (ADS)

    Zhang, Ziheng; Martin, Jonathan; Wu, Jinfeng; Wang, Haijiang; Promislow, Keith; Balcom, Bruce J.

    2008-08-01

    Water management is critical to optimize the operation of polymer electrolyte membrane fuel cells. At present, numerical models are employed to guide water management in such fuel cells. Accurate measurements of water content variation in polymer electrolyte membrane fuel cells are required to validate these models and to optimize fuel cell behavior. We report a direct water content measurement across the Nafion membrane in an operational polymer electrolyte membrane fuel cell, employing double half k-space spin echo single point imaging techniques. The MRI measurements with T2 mapping were undertaken with a parallel plate resonator to avoid the effects of RF screening. The parallel plate resonator employs the electrodes inherent to the fuel cell to create a resonant circuit at RF frequencies for MR excitation and detection, while still operating as a conventional fuel cell at DC. Three stages of fuel cell operation were investigated: activation, operation and dehydration. Each profile was acquired in 6 min, with 6 μm nominal resolution and a SNR of better than 15.

  11. Magnetic resonance imaging of water content across the Nafion membrane in an operational PEM fuel cell.

    PubMed

    Zhang, Ziheng; Martin, Jonathan; Wu, Jinfeng; Wang, Haijiang; Promislow, Keith; Balcom, Bruce J

    2008-08-01

    Water management is critical to optimize the operation of polymer electrolyte membrane fuel cells. At present, numerical models are employed to guide water management in such fuel cells. Accurate measurements of water content variation in polymer electrolyte membrane fuel cells are required to validate these models and to optimize fuel cell behavior. We report a direct water content measurement across the Nafion membrane in an operational polymer electrolyte membrane fuel cell, employing double half k-space spin echo single point imaging techniques. The MRI measurements with T2 mapping were undertaken with a parallel plate resonator to avoid the effects of RF screening. The parallel plate resonator employs the electrodes inherent to the fuel cell to create a resonant circuit at RF frequencies for MR excitation and detection, while still operating as a conventional fuel cell at DC. Three stages of fuel cell operation were investigated: activation, operation and dehydration. Each profile was acquired in 6 min, with 6 microm nominal resolution and a SNR of better than 15.

  12. Characteristics of liquid stannum anode fuel cell operated in battery mode and CO/H2/carbon fuel mode

    NASA Astrophysics Data System (ADS)

    Wang, Hongjian; Shi, Yixiang; Cai, Ningsheng

    2014-01-01

    A liquid Stannum (Sn) anode fuel cell is fabricated by using smooth single crystal Yttria Stabilized Zirconia (YSZ) electrolyte and porous Pt cathode. The cell performance in the battery mode is tested to identify the intrinsic reaction kinetics of the Sn electrochemical oxidation reaction. The cell performance characteristics in the gas fuel mode and carbon fuel mode are experimentally measured to identify limiting steps in different operating modes. The results show that in the battery mode, the SnO2 film formation blocks the transportation path of the liquid Sn and oxygen ions to the reactive interface. In the gas fuel modes, the cell performance operating in the H2 fuel mode is much higher than that in the CO fuel mode which is ascribing to the effective reaction of the formed SnO2 at the reactive interface between electrolyte and anode. In the carbon fuel mode, the carbon black fuel can directly or indirectly reduce part of the SnO2 at the interface between anode and electrolyte. It apparently indicates that the performance improvements of liquid Sn anode direct carbon fuel cell rely on minimizing the effects of formed SnO2 layer and accelerating species transportation processes within the liquid Sn electrode.

  13. Analysis of long-time operation of micro-cogeneration unit with fuel cell

    NASA Astrophysics Data System (ADS)

    Patsch, Marek; Čaja, Alexander

    2015-05-01

    Micro-cogeneration is cogeneration with small performance, with maximal electric power up to 50 kWe. On the present, there are available small micro-cogeneration units with small electric performance, about 1 kWe, which are usable also in single family houses or flats. These micro-cogeneration units operate on principle of conventional combustion engine, Stirling engine, steam engine or fuel cell. Micro-cogeneration units with fuel cells are new progressive developing type of units for single family houses. Fuel cell is electrochemical device which by oxidation-reduction reaction turn directly chemical energy of fuel to electric power, secondary products are pure water and thermal energy. The aim of paper is measuring and evaluation of operation parameters of micro-cogeneration unit with fuel cell which uses natural gas as a fuel.

  14. Purge gas protected transportable pressurized fuel cell modules and their operation in a power plant

    DOEpatents

    Zafred, Paolo R.; Dederer, Jeffrey T.; Gillett, James E.; Basel, Richard A.; Antenucci, Annette B.

    1996-01-01

    A fuel cell generator apparatus and method of its operation involves: passing pressurized oxidant gas, (O) and pressurized fuel gas, (F), into fuel cell modules, (10 and 12), containing fuel cells, where the modules are each enclosed by a module housing (18), surrounded by an axially elongated pressure vessel (64), where there is a purge gas volume, (62), between the module housing and pressure vessel; passing pressurized purge gas, (P), through the purge gas volume, (62), to dilute any unreacted fuel gas from the modules; and passing exhaust gas, (82), and circulated purge gas and any unreacted fuel gas out of the pressure vessel; where the fuel cell generator apparatus is transpatable when the pressure vessel (64) is horizontally disposed, providing a low center of gravity.

  15. Optimal design and operation of solid oxide fuel cell systems for small-scale stationary applications

    NASA Astrophysics Data System (ADS)

    Braun, Robert Joseph

    The advent of maturing fuel cell technologies presents an opportunity to achieve significant improvements in energy conversion efficiencies at many scales; thereby, simultaneously extending our finite resources and reducing "harmful" energy-related emissions to levels well below that of near-future regulatory standards. However, before realization of the advantages of fuel cells can take place, systems-level design issues regarding their application must be addressed. Using modeling and simulation, the present work offers optimal system design and operation strategies for stationary solid oxide fuel cell systems applied to single-family detached dwellings. A one-dimensional, steady-state finite-difference model of a solid oxide fuel cell (SOFC) is generated and verified against other mathematical SOFC models in the literature. Fuel cell system balance-of-plant components and costs are also modeled and used to provide an estimate of system capital and life cycle costs. The models are used to evaluate optimal cell-stack power output, the impact of cell operating and design parameters, fuel type, thermal energy recovery, system process design, and operating strategy on overall system energetic and economic performance. Optimal cell design voltage, fuel utilization, and operating temperature parameters are found using minimization of the life cycle costs. System design evaluations reveal that hydrogen-fueled SOFC systems demonstrate lower system efficiencies than methane-fueled systems. The use of recycled cell exhaust gases in process design in the stack periphery are found to produce the highest system electric and cogeneration efficiencies while achieving the lowest capital costs. Annual simulations reveal that efficiencies of 45% electric (LHV basis), 85% cogenerative, and simple economic paybacks of 5--8 years are feasible for 1--2 kW SOFC systems in residential-scale applications. Design guidelines that offer additional suggestions related to fuel cell

  16. Trial operation of a phosphoric acid fuel cell (PC25) for CHP applications in Europe

    SciTech Connect

    Uhrig, M.; Droste, W.; Wolf, D.

    1996-12-31

    In Europe, ten 200 kW phosphoric acid fuel cells (PAFCs) produced by ONSI (PC25) are currently in operation. Their operators collaborate closely in the European Fuel Cell Users Group (EFCUG). The experience gained from trial operation by the four German operators - HEAG, HGW/HEW, Thyssengas and Ruhrgas - coincides with that of the other European operators. This experience can generally be regarded as favourable. With a view to using fuel cells in combined heat and power generation (CHP), the project described in this report, which was carried out in cooperation with the municipal utility of Bochum and Gasunie of the Netherlands, aimed at gaining experience with the PC 25 in field operation under the specific operating conditions prevailing in Europe. The work packages included heat-controlled operation, examination of plant behavior with varying gas properties and measurement of emissions under dynamic load conditions. The project received EU funding under the JOULE programme.

  17. High pressure operation of tubular solid oxide fuel cells and their intergration with gas turbines

    SciTech Connect

    Haynes, C.; Wepfer, W.J.

    1996-12-31

    Fossil fuels continue to be used at a rate greater than that of their natural formation, and the current byproducts from their use are believed to have a detrimental effect on the environment (e.g. global warming). There is thus a significant impetus to have cleaner, more efficient fuel consumption alternatives. Recent progress has led to renewed vigor in the development of fuel cell technology, which has been shown to be capable of producing high efficiencies with relatively benign exhaust products. The tubular solid oxide fuel cell developed by Westinghouse Electric Corporation has shown significant promise. Modeling efforts have been and are underway to optimize and better understand this fuel cell technology. Thus far, the bulk of modeling efforts has been for operation at atmospheric pressure. There is now interest in developing high-efficiency integrated gas turbine/solid oxide fuel cell systems. Such operation of fuel cells would obviously occur at higher pressures. The fuel cells have been successfully modeled under high pressure operation and further investigated as integrated components of an open loop gas turbine cycle.

  18. Purge gas protected transportable pressurized fuel cell modules and their operation in a power plant

    DOEpatents

    Zafred, P.R.; Dederer, J.T.; Gillett, J.E.; Basel, R.A.; Antenucci, A.B.

    1996-11-12

    A fuel cell generator apparatus and method of its operation involves: passing pressurized oxidant gas and pressurized fuel gas into modules containing fuel cells, where the modules are each enclosed by a module housing surrounded by an axially elongated pressure vessel, and where there is a purge gas volume between the module housing and pressure vessel; passing pressurized purge gas through the purge gas volume to dilute any unreacted fuel gas from the modules; and passing exhaust gas and circulated purge gas and any unreacted fuel gas out of the pressure vessel; where the fuel cell generator apparatus is transportable when the pressure vessel is horizontally disposed, providing a low center of gravity. 11 figs.

  19. In-ground operation of Geothermic Fuel Cells for unconventional oil and gas recovery

    NASA Astrophysics Data System (ADS)

    Sullivan, Neal; Anyenya, Gladys; Haun, Buddy; Daubenspeck, Mark; Bonadies, Joseph; Kerr, Rick; Fischer, Bernhard; Wright, Adam; Jones, Gerald; Li, Robert; Wall, Mark; Forbes, Alan; Savage, Marshall

    2016-01-01

    This paper presents operating and performance characteristics of a nine-stack solid-oxide fuel cell combined-heat-and-power system. Integrated with a natural-gas fuel processor, air compressor, reactant-gas preheater, and diagnostics and control equipment, the system is designed for use in unconventional oil-and-gas processing. Termed a ;Geothermic Fuel Cell; (GFC), the heat liberated by the fuel cell during electricity generation is harnessed to process oil shale into high-quality crude oil and natural gas. The 1.5-kWe SOFC stacks are packaged within three-stack GFC modules. Three GFC modules are mechanically and electrically coupled to a reactant-gas preheater and installed within the earth. During operation, significant heat is conducted from the Geothermic Fuel Cell to the surrounding geology. The complete system was continuously operated on hydrogen and natural-gas fuels for ∼600 h. A quasi-steady operating point was established to favor heat generation (29.1 kWth) over electricity production (4.4 kWe). Thermodynamic analysis reveals a combined-heat-and-power efficiency of 55% at this condition. Heat flux to the geology averaged 3.2 kW m-1 across the 9-m length of the Geothermic Fuel Cell-preheater assembly. System performance is reviewed; some suggestions for improvement are proposed.

  20. Transient operation and shape optimization of a single PEM fuel cell

    NASA Astrophysics Data System (ADS)

    Chen, Sheng; Ordonez, Juan C.; Vargas, Jose V. C.; Gardolinski, Jose E. F.; Gomes, Maria A. B.

    Geometric design, including the internal structure and external shape, considerably affect the thermal, fluid, and electrochemical characteristics of a polymer electrolyte membrane (PEM) fuel cell, which determine the polarization curves as well as the thermal and power inertias. Shape optimization is a natural alternative to improve the fuel cell performance and make fuel cells more attractive for power generation. This paper investigates the internal and external structure effects on the fuel cell steady and transient operation with consideration of stoichiometric ratios, pumping power, and working temperature limits. The maximal steady state net power output and the fuel cell start-up time under a step-changed current load characterize the fuel cell steady and transient performance respectively. The one-dimensional PEM fuel cell (PEMFC) thermal model introduced in a previous work [J.V.C. Vargas, J.C. Ordonez, A. Bejan, Constructal flow structure for a PEM fuel cell, Int. J. Heat Mass Transfer 47 (2004) 4177-4193] is amended to simulate the fuel cell transient start-up process. The shape optimization consists of the internal and external PEMFC structure optimization. The internal optimization focuses on the optimal allocation of fuel cell compartment thicknesses. The external optimization process seeks the PEM fuel cell optimal external aspect ratios. These two levels of optimizations pursue the optimal geometric design with quick response to the step loads and large power densities. Appropriate dimensionless groups are identified and the numerical results are presented in dimensionless charts for general engineering design. The universality of the general optimal shape found is also discussed.

  1. Analysis of Actual Operating Conditions of an Off-grid Solid Oxide Fuel Cell

    SciTech Connect

    Dennis Witmer; Thomas Johnson; Jack Schmid

    2008-12-31

    Fuel cells have been proposed as ideal replacements for other technologies in remote locations such as Rural Alaska. A number of suppliers have developed systems that might be applicable in these locations, but there are several requirements that must be met before they can be deployed: they must be able to operate on portable fuels, and be able to operate with little operator assistance for long periods of time. This project was intended to demonstrate the operation of a 5 kW fuel cell on propane at a remote site (defined as one without access to grid power, internet, or cell phone, but on the road system). A fuel cell was purchased by the National Park Service for installation in their newly constructed visitor center at Exit Glacier in the Kenai Fjords National Park. The DOE participation in this project as initially scoped was for independent verification of the operation of this demonstration. This project met with mixed success. The fuel cell has operated over 6 seasons at the facility with varying degrees of success, with one very good run of about 1049 hours late in the summer of 2006, but in general the operation has been below expectations. There have been numerous stack failures, the efficiency of electrical generation has been lower than expected, and the field support effort required has been far higher than expected. Based on the results to date, it appears that this technology has not developed to the point where demonstrations in off road sites are justified.

  2. A comparison of low-pressure and supercharged operation of polymer electrolyte membrane fuel cell systems for aircraft applications

    NASA Astrophysics Data System (ADS)

    Werner, C.; Preiß, G.; Gores, F.; Griebenow, M.; Heitmann, S.

    2016-08-01

    Multifunctional fuel cell systems are competitive solutions aboard future generations of civil aircraft concerning energy consumption, environmental issues, and safety reasons. The present study compares low-pressure and supercharged operation of polymer electrolyte membrane fuel cells with respect to performance and efficiency criteria. This is motivated by the challenge of pressure-dependent fuel cell operation aboard aircraft with cabin pressure varying with operating altitude. Experimental investigations of low-pressure fuel cell operation use model-based design of experiments and are complemented by numerical investigations concerning supercharged fuel cell operation. It is demonstrated that a low-pressure operation is feasible with the fuel cell device under test, but that its range of stable operation changes between both operating modes. Including an external compressor, it can be shown that the power demand for supercharging the fuel cell is about the same as the loss in power output of the fuel cell due to low-pressure operation. Furthermore, the supercharged fuel cell operation appears to be more sensitive with respect to variations in the considered independent operating parameters load requirement, cathode stoichiometric ratio, and cooling temperature. The results indicate that a pressure-dependent self-humidification control might be able to exploit the potential of low-pressure fuel cell operation for aircraft applications to the best advantage.

  3. Method for reducing fuel cell output voltage to permit low power operation

    DOEpatents

    Reiser, Carl A.; Landau, Michael B.

    1980-01-01

    Fuel cell performance is degraded by recycling a portion of the cathode exhaust through the cells and, if necessary, also reducing the total air flow to the cells for the purpose of permitting operation below a power level which would otherwise result in excessive voltage.

  4. Influence of anode surface chemistry on microbial fuel cell operation.

    PubMed

    Santoro, Carlo; Babanova, Sofia; Artyushkova, Kateryna; Cornejo, Jose A; Ista, Linnea; Bretschger, Orianna; Marsili, Enrico; Atanassov, Plamen; Schuler, Andrew J

    2015-12-01

    Self-assembled monolayers (SAMs) modified gold anodes are used in single chamber microbial fuel cells for organic removal and electricity generation. Hydrophilic (N(CH3)3(+), OH, COOH) and hydrophobic (CH3) SAMs are examined for their effect on bacterial attachment, current and power output. The different substratum chemistry affects the community composition of the electrochemically active biofilm formed and thus the current and power output. Of the four SAM-modified anodes tested, N(CH3)3(+) results in the shortest start up time (15 days), highest current achieved (225 μA cm(-2)) and highest MFC power density (40 μW cm(-2)), followed by COOH (150 μA cm(-2) and 37 μW cm(-2)) and OH (83 μA cm(-2) and 27 μW cm(-2)) SAMs. Hydrophobic SAM decreases electrochemically active bacteria attachment and anode performance in comparison to hydrophilic SAMs (CH3 modified anodes 7 μA cm(-2) anodic current and 1.2 μW cm(-2) MFC's power density). A consortium of Clostridia and δ-Proteobacteria is found on all the anode surfaces, suggesting a synergistic cooperation under anodic conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Microbial fuel cells operating on mixed fatty acids.

    PubMed

    Freguia, Stefano; Teh, Ee Hoi; Boon, Nico; Leung, Kar Man; Keller, Jurg; Rabaey, Korneel

    2010-02-01

    Strategies are being developed to harvest the energy content of the wasted sludge generated from the treatment of domestic wastewater. Sludge can be hydrolysed and fermented, giving a mixture of volatile fatty acids (VFAs). Based on the composition of such a fermented stream, synthetic media were created and tested for VFA conversion in microbial fuel cells (MFCs). Mainly acetate and propionate were preferred as electron donors in the mixed VFA system, which generated a power density of 49+/-1 mW L(NAC)(-1). The other VFAs (butyrates/valerates/caproic acid) were also removed, albeit at lower rates. In single VFA tests, each VFA could be removed, but particularly i-butyrate did not provide significant current generation. PCR-DGGE indicated that the microbial community structure was highly determined by the fed VFA, rather than by the initial inoculum. The communities were dominated by Proteobacteria such as Geobacter, Comamonas, Pseudomonas and Pelobacter species. This study demonstrated the feasibility of using fatty acids, as present in fermented sludge hydrolysates, for current generation.

  6. A Reversible Planar Solid Oxide Fuel-Fed Electrolysis Cell and Solid Oxide Fuel Cell for Hydrogen and Electricity Production Operating on Natural Gas/Biomass Fuels

    SciTech Connect

    Tao, Greg, G.

    2007-03-31

    A solid oxide fuel-assisted electrolysis technique was developed to co-generate hydrogen and electricity directly from a fuel at a reduced cost of electricity. Solid oxide fuel-assisted electrolysis cells (SOFECs), which were comprised of 8YSZ electrolytes sandwiched between thick anode supports and thin cathodes, were constructed and experimentally evaluated at various operation conditions on lab-level button cells with 2 cm2 per-cell active areas as well as on bench-scale stacks with 30 cm2 and 100 cm2 per-cell active areas. To reduce the concentration overpotentials, pore former systems were developed and engineered to optimize the microstructure and morphology of the Ni+8YSZ-based anodes. Chemically stable cathode materials, which possess good electronic and ionic conductivity and exhibit good electrocatalytic properties in both oxidizing and reducing gas atmospheres, were developed and materials properties were investigated. In order to increase the specific hydrogen production rate and thereby reduce the system volume and capital cost for commercial applications, a hybrid system that integrates the technologies of the SOFEC and the solid-oxide fuel cell (SOFC), was developed and successfully demonstrated at a 1kW scale, co-generating hydrogen and electricity directly from chemical fuels.

  7. Dissolution of Platinum in the Operational Range of Fuel Cells

    PubMed Central

    Keeley, Gareth P.; Geiger, Simon; Zeradjanin, Aleksandar R.; Hodnik, Nejc; Kulyk, Nadiia

    2015-01-01

    Abstract One of the most important practical issues in low‐temperature fuel‐cell catalyst degradation is platinum dissolution. According to the literature, it initiates at 0.6–0.9 VRHE, whereas previous time‐ and potential‐resolved inductively coupled plasma mass spectrometry (ICP–MS) experiments, however, revealed dissolution onset at only 1.05 VRHE. In this manuscript, the apparent discrepancy is addressed by investigating bulk and nanoparticulated catalysts. It is shown that, given enough time for accumulation, traces of platinum can be detected at potentials as low as 0.85 VRHE. At these low potentials, anodic dissolution is the dominant process, whereas, at more positive potentials, more platinum dissolves during the oxide reduction after accumulation. Interestingly, the potential and time dissolution dependence is similar for both types of electrode. Dissolution processes are discussed with relevance to fuel‐cell operation and plausible dissolution mechanisms are considered. PMID:27525206

  8. Fuel cells

    NASA Astrophysics Data System (ADS)

    1984-12-01

    The US Department of Energy (DOE), Office of Fossil Energy, has supported and managed a fuel cell research and development (R and D) program since 1976. Responsibility for implementing DOE's fuel cell program, which includes activities related to both fuel cells and fuel cell systems, has been assigned to the Morgantown Energy Technology Center (METC) in Morgantown, West Virginia. The total United States effort of the private and public sectors in developing fuel cell technology is referred to as the National Fuel Cell Program (NFCP). The goal of the NFCP is to develop fuel cell power plants for base-load and dispersed electric utility systems, industrial cogeneration, and on-site applications. To achieve this goal, the fuel cell developers, electric and gas utilities, research institutes, and Government agencies are working together. Four organized groups are coordinating the diversified activities of the NFCP. The status of the overall program is reviewed in detail.

  9. EXPERIMENTAL AND NUMERICAL ANALYSIS OF SUBFREEZING OPERATION IN PEM FUEL CELLS

    SciTech Connect

    Mukherjee, Partha P

    2010-01-01

    In this work, we present the neutron radiography and analysis, as well as modeling predictions of cold-start operation of PEM fuel cells. Fuel cells with Gore or LANL MEAs and SGL or E-Tek ELAT GDLs are tested in varying subfreezing temperatures (-40 to 0 C) to determine time to failure, amount of water formation, and place of water formation. Theoretical modeling is also conducted and model predictions are compared with the cell voltage evolution during subfreezing operation. A higher PTFE-loading in the MPL is found to decrease loss in ESCA in our case.

  10. Operating experiences with a molten carbonate fuel cell at Stuttgart-Möhringen wastewater treatment plant.

    PubMed

    Locher, C; Meyer, C; Steinmetz, H

    2012-01-01

    Fuel cells on wastewater treatment plants are a relatively new technology to convert biogas from anaerobic digestion into thermal and electrical energy. Since the end of 2007, a type of MCFC fuel cell (>250 kW(el), 180 kW(th)) has been installed at Stuttgart-Möhringen wastewater treatment plant. The goals of this research project are to raise the power self-sufficiency in Stuttgart-Möhringen, to further optimise high temperature fuel cells using biogas and to gain practical experience. After approximately 9,000 h of operation, a mean electrical 'gross'-efficiency of 44% was achieved. To fully exploit this high electrical efficiency, it is essential to keep the energy consumption of peripheral devices (gas pressure unit, gas cleaning unit, etc.) of the fuel cell as low as possible.

  11. A new topology of fuel cell hybrid power source for efficient operation and high reliability

    NASA Astrophysics Data System (ADS)

    Bizon, Nicu

    2011-03-01

    This paper analyzes a new fuel cell Hybrid Power Source (HPS) topology having the feature to mitigate the current ripple of the fuel cell inverter system. In the operation of the inverter system that is grid connected or supplies AC motors in vehicle application, the current ripple normally appears at the DC port of the fuel cell HPS. Consequently, if mitigation measures are not applied, this ripple is back propagated to the fuel cell stack. Other features of the proposed fuel cell HPS are the Maximum Power Point (MPP) tracking, high reliability in operation under sharp power pulses and improved energy efficiency in high power applications. This topology uses an inverter system directly powered from the appropriate fuel cell stack and a controlled buck current source as low power source used for ripple mitigation. The low frequency ripple mitigation is based on active control. The anti-ripple current is injected in HPS output node and this has the LF power spectrum almost the same with the inverter ripple. Consequently, the fuel cell current ripple is mitigated by the designed active control. The ripple mitigation performances are evaluated by indicators that are defined to measure the mitigation ratio of the low frequency harmonics. In this paper it is shown that good performances are obtained by using the hysteretic current control, but better if a dedicated nonlinear controller is used. Two ways to design the nonlinear control law are proposed. First is based on simulation trials that help to draw the characteristic of ripple mitigation ratio vs. fuel cell current ripple. The second is based on Fuzzy Logic Controller (FLC). The ripple factor is up to 1% in both cases.

  12. Effect of dynamic operation on chemical degradation of a polymer electrolyte membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Jung, Minjae; Williams, Keith A.

    2011-03-01

    Dynamic operation is known as one of the factors for accelerating chemical degradation of the polymer electrolyte membrane in a polymer electrolyte membrane fuel cell (PEMFC). However, little effort has been made dealing with the quantification of the degradation process. In this investigation, cyclic current operation is carried out on a fuel cell system, and the frequency effect of cyclic operation on chemical degradation is investigated. The dynamic behavior of a fuel cell system is analyzed first with the modified Randles model, where the charge double layer is modeled by three components; a charge transfer resistance (Rct), and two RC cells for the Warburg impedance. After calculating each parameter value through exponential curve fitting, the dynamic behaviors of the three components are simulated using MATLAB Simulink®. Fluoride release as a function of the frequency of cyclic operation is evaluated by measuring the concentration of fluoride ion in effluent from a fuel cell exhaust. The frequency effect on chemical degradation is explained by comparing the simulated results and the fluoride release results. Two possible reasons for the accelerated degradation at cyclic operation are also suggested.

  13. Heat and fuel coupled operation of a high temperature polymer electrolyte fuel cell with a heat exchanger methanol steam reformer

    NASA Astrophysics Data System (ADS)

    Schuller, G.; Vázquez, F. Vidal; Waiblinger, W.; Auvinen, S.; Ribeirinha, P.

    2017-04-01

    In this work a methanol steam reforming (MSR) reactor has been operated thermally coupled to a high temperature polymer electrolyte fuel cell stack (HT-PEMFC) utilizing its waste heat. The operating temperature of the coupled system was 180 °C which is significantly lower than the conventional operating temperature of the MSR process which is around 250 °C. A newly designed heat exchanger reformer has been developed by VTT (Technical Research Center of Finland LTD) and was equipped with commercially available CuO/ZnO/Al2O3 (BASF RP-60) catalyst. The liquid cooled, 165 cm2, 12-cell stack used for the measurements was supplied by Serenergy A/S. The off-heat from the electrochemical fuel cell reaction was transferred to the reforming reactor using triethylene glycol (TEG) as heat transfer fluid. The system was operated up to 0.4 A cm-2 generating an electrical power output of 427 Wel. A total stack waste heat utilization of 86.4% was achieved. It has been shown that it is possible to transfer sufficient heat from the fuel cell stack to the liquid circuit in order to provide the needed amount for vaporizing and reforming of the methanol-water-mixture. Furthermore a set of recommendations is given for future system design considerations.

  14. The effect of the parasitic current on the Direct Ethanol PEM Fuel Cell Operation

    NASA Astrophysics Data System (ADS)

    Andreadis, G. M.; Podias, A. K. M.; Tsiakaras, P. E.

    In the present work the effect of the parasitic or leakage current, I p, which is the result of the ethanol crossover through the polymer electrolyte membrane (PEM) from the anode to the cathode side of the cell, on both the cathode activation overpotential and the fuel cell operation is investigated. A one-dimensional (1-D), isothermal mathematical model is developed in order to describe the operation of a Direct Ethanol PEM Fuel Cell (DE-PEMFC) in steady state. The equations used describe the mass transport of both ethanol and humidified oxygen at the anode and the cathode compartment of the cell respectively. The mathematical model is validated against experimental data and a relatively good agreement between the model predictions and the experimental results is found. The direct correlation that exists between the ethanol crossover rate and the parasitic current formation is graphically depicted. Moreover, when the parasitic current is enabled and disabled, the calculation of the cathode activation overpotential shows that the mixed overpotential for a DE-PEMFC poses a serious problem hindering the fuel cell operation. According to the model results, the parasitic current is greater at low current density values due to the greater amounts of the crossovered ethanol. Finally, the effect of both the oxygen feed concentration and the parasitic current formation on the fuel cell operation is also presented and discussed.

  15. Direct hydrocarbon fuel cells

    DOEpatents

    Barnett, Scott A.; Lai, Tammy; Liu, Jiang

    2010-05-04

    The direct electrochemical oxidation of hydrocarbons in solid oxide fuel cells, to generate greater power densities at lower temperatures without carbon deposition. The performance obtained is comparable to that of fuel cells used for hydrogen, and is achieved by using novel anode composites at low operating temperatures. Such solid oxide fuel cells, regardless of fuel source or operation, can be configured advantageously using the structural geometries of this invention.

  16. The effect of operation and design parameters on the performance of the direct methanol fuel cell

    SciTech Connect

    Simpson, S.F.; Cisar, A.; Franaszczuk, K.

    1996-12-31

    Fuel cell technology continues to receive considerable attention as a potential replacement for fossil fuels as a primary source of terrestrial power. Ideally, such power systems would operate at relatively low temperatures (< 100{degrees}C) which suggests strongly the use of cell technology based upon the proton exchange membrane (PEM). Without question, hydrogen is a very desirable fuel choice for these types of systems, because of its high energy density. However, the difficulties associated with the production and routine handling of hydrogen limit severely its commercial use at present. The direct methanol fuel cell (DMFC) is a particularly attractive alternative to the use of the hydrogen/oxygen cell. Although not as high as hydrogen, the energy density of methanol is the highest among the organic fuels. Furthermore, because of the similarity in liquid handling requirements between methanol and gasoline, a significant portion of the infrastructure necessary for the marketing and distribution of the fuel is already in place. Other inherent attributes of the DMFC which include rapid start-up and operation with little or no emission or noise signature have led to an intense DMFC research effort over the past twenty years and, indeed, the DMFC has even been referred to as {open_quotes}the electrochemist`s dream{close_quotes}.

  17. Effectiveness of paper-structured catalyst for the operation of biodiesel-fueled solid oxide fuel cell

    NASA Astrophysics Data System (ADS)

    Quang-Tuyen, Tran; Kaida, Taku; Sakamoto, Mio; Sasaki, Kazunari; Shiratori, Yusuke

    2015-06-01

    Mg/Al-hydrotalcite (HDT)-dispersed paper-structured catalyst (PSC) was prepared by a simple paper-making process. The PSC exhibited excellent catalytic activity for the steam reforming of model biodiesel fuel (BDF), pure oleic acid methyl ester (oleic-FAME, C19H36O2) which is a mono-unsaturated component of practical BDFs. The PSC exhibited fuel conversion comparable to a pelletized catalyst material, here, conventional Ni-zirconia cermet anode for solid oxide fuel cell (SOFC) with less than one-hundredth Ni weight. Performance of electrolyte-supported cell connected with the PSC was evaluated in the feed of oleic-FAME, and stable operation was achieved. After 60 h test, coking was not observed in both SOFC anode and PSC.

  18. Quantitative study of ruthenium cross-over in direct methanol fuel cells during early operation hours

    NASA Astrophysics Data System (ADS)

    Schoekel, A.; Melke, J.; Bruns, M.; Wippermann, K.; Kuppler, F.; Roth, C.

    2016-01-01

    In direct methanol fuel cells (DMFC), ruthenium cross-over is an important degradation phenomenon. The loss of ruthenium from the anode, its transport through the membrane and its deposition onto the cathode are detrimental to the fuel cell performance and limit the fuel cell's lifetime. Here we present a quantitative study on the fraction of ruthenium being transferred from the anode to the cathode during early operation hours (0-100 h) of a DMFC. Already during fabrication of the MEA ruthenium is transferred to the cathode. In our pristine MEAs about 0.024 wt% Ru could be found in the cathode catalyst. The cell potential during operation seems to have only a minor influence on the dissolution process. In contrast, the operation time appears to be much more important. Our data hint at two dissolution processes: a fast process dominating the first hours of operation and a slower process, which is responsible for the ongoing ruthenium transfer during the fuel cell lifetime. After 2 h held at open circuit conditions the Ru content of the cathode side was 10 times higher than in the pristine MEA. In contrast, the slower process increased that amount only by a factor of two over the course of another 100 h.

  19. Effect of operating parameters and anode gas impurities upon polymer electrolyte fuel cells

    SciTech Connect

    Weisbrod, K.R.; Vanderborgh, N.E.

    1994-07-01

    PEM fuel cells are actively under development for transportation and other applications. Integration of a PEM fuel cell stack with a methanol reformer requires an understanding of single cell performance under a range of operating conditions using anode gas contaminated with impurities. The effect of temperature, pressure, and anode gas impurities on single cell PEM performance was investigated with platinum black electrodes. Single cell performance remained unchanged as temperature was varied between 80 and 100 at 3 atm pressure. High water partial pressures at 120C produced a mass transfer limiting current. While operation at 120C did not reverse CO{sub 2} poisoning, anode air addition proved effective. Air injection also decreased CO poisoning at injected concentrations up to 200 ppm CO. Higher single cell tolerance was observed for CH{sub 3}OH than CO. Up to 1 mole % CH{sub 3}OH in the gas phase reduced the current density by less than 10%.

  20. Carbon corrosion in PEM fuel cells during drive cycle operation

    DOE PAGES

    Borup, Rodney L.; Papadias, D. D.; Mukundan, Rangachary; ...

    2015-09-14

    One of the major contributors to degradation involves the electrocatalyst, including the corrosion of the carbons used as catalyst supports, which leads to changes in the catalyst layer structure. We have measured and quantified carbon corrosion during drive cycle operation and as a variation of the upper and lower potential limits used during drive cycle operation. The amount of carbon corrosion is exacerbated by the voltage cycling inherent in the drive cycle compared with constant potential operation. The potential gap between upper and lower potentials appears to be more important than the absolute operating potentials in the normal operating potentialmore » regime (0.40V to 0.95V) as changes in the measured carbon corrosion are similar when the upper potential was lower compared to raising the lower potential. Catalyst layer thinning was observed during the simulated drive cycle operation which had an associated decrease in catalyst layer porosity. This catalyst layer thinning is not due solely to carbon corrosion, although carbon corrosion likely plays a role; much of this thinning must be from compaction of the material in the catalyst layer. As a result, the decrease in catalyst layer porosity leads to additional performance losses due to mass transport losses.« less

  1. Carbon corrosion in PEM fuel cells during drive cycle operation

    SciTech Connect

    Borup, Rodney L.; Papadias, D. D.; Mukundan, Rangachary; Spernjak, Dusan; Langlois, David Alan; Ahluwalia, Rajesh; More, Karen L.; Grot, Steve

    2015-09-14

    One of the major contributors to degradation involves the electrocatalyst, including the corrosion of the carbons used as catalyst supports, which leads to changes in the catalyst layer structure. We have measured and quantified carbon corrosion during drive cycle operation and as a variation of the upper and lower potential limits used during drive cycle operation. The amount of carbon corrosion is exacerbated by the voltage cycling inherent in the drive cycle compared with constant potential operation. The potential gap between upper and lower potentials appears to be more important than the absolute operating potentials in the normal operating potential regime (0.40V to 0.95V) as changes in the measured carbon corrosion are similar when the upper potential was lower compared to raising the lower potential. Catalyst layer thinning was observed during the simulated drive cycle operation which had an associated decrease in catalyst layer porosity. This catalyst layer thinning is not due solely to carbon corrosion, although carbon corrosion likely plays a role; much of this thinning must be from compaction of the material in the catalyst layer. As a result, the decrease in catalyst layer porosity leads to additional performance losses due to mass transport losses.

  2. FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS: CONCEPTUAL DESIGN AND ASSESSMENT

    EPA Science Inventory

    The conceptual design of a fuel cell (FC) system for operation on anaerobic digester gas (ADG) is described and its economic and environmental feasibility is projected. ADG is produced at water treatment plants during the process of treating sewage anaerobically to reduce solids....

  3. FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS: CONCEPTUAL DESIGN AND ASSESSMENT

    EPA Science Inventory

    The conceptual design of a fuel cell (FC) system for operation on anaerobic digester gas (ADG) is described and its economic and environmental feasibility is projected. ADG is produced at water treatment plants during the process of treating sewage anaerobically to reduce solids....

  4. Fuel cells feasibility

    NASA Technical Reports Server (NTRS)

    Schonfeld, D.; Charng, T.

    1981-01-01

    The technical and economic status of fuel cells is assessed with emphasis on their potential benefits to the Deep Space Network. The fuel cell, what it is, how it operates, and what its outputs are, is reviewed. Major technical problems of the fuel cell and its components are highlighted. Due to these problems and economic considerations it is concluded that fuel cells will not become commercially viable until the early 1990s.

  5. Rejuvenation of automotive fuel cells

    SciTech Connect

    Kim, Yu Seung; Langlois, David A.

    2016-08-23

    A process for rejuvenating fuel cells has been demonstrated to improve the performance of polymer exchange membrane fuel cells with platinum/ionomer electrodes. The process involves dehydrating a fuel cell and exposing at least the cathode of the fuel cell to dry gas (nitrogen, for example) at a temperature higher than the operating temperature of the fuel cell. The process may be used to prolong the operating lifetime of an automotive fuel cell.

  6. Dynamic modeling and evaluation of solid oxide fuel cell - combined heat and power system operating strategies

    NASA Astrophysics Data System (ADS)

    Nanaeda, Kimihiro; Mueller, Fabian; Brouwer, Jacob; Samuelsen, Scott

    Operating strategies of solid oxide fuel cell (SOFC) combined heat and power (CHP) systems are developed and evaluated from a utility, and end-user perspective using a fully integrated SOFC-CHP system dynamic model that resolves the physical states, thermal integration and overall efficiency of the system. The model can be modified for any SOFC-CHP system, but the present analysis is applied to a hotel in southern California based on measured electric and heating loads. Analysis indicates that combined heat and power systems can be operated to benefit both the end-users and the utility, providing more efficient electric generation as well as grid ancillary services, namely dispatchable urban power. Design and operating strategies considered in the paper include optimal sizing of the fuel cell, thermal energy storage to dispatch heat, and operating the fuel cell to provide flexible grid power. Analysis results indicate that with a 13.1% average increase in price-of-electricity (POE), the system can provide the grid with a 50% operating range of dispatchable urban power at an overall thermal efficiency of 80%. This grid-support operating mode increases the operational flexibility of the SOFC-CHP system, which may make the technology an important utility asset for accommodating the increased penetration of intermittent renewable power.

  7. Fuel cells 101

    SciTech Connect

    Hirschenhofer, J.H.

    1999-07-01

    This paper discusses the various types of fuel cells, the importance of cell voltage, fuel processing for natural gas, cell stacking, fuel cell plant description, advantages and disadvantages of the types of fuel cells, and applications. The types covered include: polymer electrolyte fuel cell, alkaline fuel cell, phosphoric acid fuel cell; molten carbonate fuel cell, and solid oxide fuel cell.

  8. Microscale Fuel Cells

    SciTech Connect

    Holladay, Jamie D.; Viswanathan, Vish V.

    2005-11-03

    Perhaprs some of the most innovative work on fuel cells has been the research dedicated to applying silicon fabrication techniques to fuel cells technology creating low power microscale fuel cells applicable to microelectro mechanical systems (MEMS), microsensors, cell phones, PDA’s, and other low power (0.001 to 5 We) applications. In this small power range, fuel cells offer the decoupling of the energy converter from the energy storage which may enable longer operating times and instant or near instant charging. To date, most of the microscale fuel cells being developed have been based on proton exchange membrane fuel cell technology (PEMFC) or direct methanol fuel cell (DMFC) technology. This section will discuss requirements and considerations that need to be addressed in the development of microscale fuel cells, as well as some proposed designs and fabrication strategies.

  9. Air Breathing Direct Methanol Fuel Cell

    DOEpatents

    Ren; Xiaoming

    2003-07-22

    A method for activating a membrane electrode assembly for a direct methanol fuel cell is disclosed. The method comprises operating the fuel cell with humidified hydrogen as the fuel followed by running the fuel cell with methanol as the fuel.

  10. Development of a novel computational tool for optimizing the operation of fuel cells systems: Application for phosphoric acid fuel cells

    NASA Astrophysics Data System (ADS)

    Zervas, P. L.; Tatsis, A.; Sarimveis, H.; Markatos, N. C. G.

    Fuel cells offer a significant and promising clean technology for portable, automotive and stationary applications and, thus, optimization of their performance is of particular interest. In this study, a novel optimization tool is developed that realistically describes and optimizes the performance of fuel cell systems. First, a 3D steady-state detailed model is produced based on computational fluid dynamics (CFD) techniques. Simulated results obtained from the CFD model are used in a second step, to generate a database that contains the fuel and oxidant volumetric rates and utilizations and the corresponding cell voltages. In the third step mathematical relationships are developed between the input and output variables, using the database that has been generated in the previous step. In particular, the linear regression methodology and the radial basis function (RBF) neural network architecture are utilized for producing the input-output "meta-models". Several statistical tests are used to validate the proposed models. Finally, a multi-objective hierarchical Non-Linear Programming (NLP) problem is formulated that takes into account the constraints and limitations of the system. The multi-objective hierarchical approach is built upon two steps: first, the fuel volumetric rate is minimized, recognizing the fact that our first concern is to reduce consumption of the expensive fuel. In the second step, optimization is performed with respect to the oxidant volumetric rate. The proposed method is illustrated through its application for phosphoric acid fuel cell (PAFC) systems.

  11. Investigation of polymer electrolyte membrane fuel cell internal behaviour during long term operation and its use in prognostics

    NASA Astrophysics Data System (ADS)

    Mao, Lei; Jackson, Lisa; Jackson, Tom

    2017-09-01

    This paper investigates the polymer electrolyte membrane (PEM) fuel cell internal behaviour variation at different operating condition, with characterization test data taken at predefined inspection times, and uses the determined internal behaviour evolution to predict the future PEM fuel cell performance. For this purpose, a PEM fuel cell behaviour model is used, which can be related to various fuel cell losses. By matching the model to the collected polarization curves from the PEM fuel cell system, the variation of fuel cell internal behaviour can be obtained through the determined model parameters. From the results, the source of PEM fuel cell degradation during its lifetime at different conditions can be better understood. Moreover, with determined fuel cell internal behaviour, the future fuel cell performance can be obtained by predicting the future model parameters. By comparing with prognostic results using adaptive neuro fuzzy inference system (ANFIS), the proposed prognostic analysis can provide better predictions for PEM fuel cell performance at dynamic condition, and with the understanding of variation in PEM fuel cell internal behaviour, mitigation strategies can be designed to extend the fuel cell performance.

  12. A solid oxide fuel cell power system: 1992--1993 field operation

    SciTech Connect

    Veyo, S.E.; Kusunoki, A.; Takeuchi, S.; Kaneko, S.; Yokoyama, H.

    1994-05-01

    Westinghouse has deployed fully integrated, automatically controlled, packaged solid oxide fuel cell (SOFC) power generation systems in order to obtain useful customer feedback. Recently, Westinghouse has deployed 20 kW class natural gas fueled SOFC generator modules integrated into two 25 kW SOFC systems, the first with The UTILITIES, a Japanese consortium. The UTILITIES 25 kW SOFC system is the focus of this paper. The unit was shipped to the Rokko Island Test Center for Advanced Energy Systems (near Kobe, Japan) operated by Kansai Electric Power Co.; testing was initiated February 1992. Module A operated for 2601 hours at an ave output 16.6 kW dc; final shutdown was induced by current stability problems with dissipator (restart not possible because of damaged cells). Module B operated for 1579 hours at ave output 17.8 kWdc. The unit was damaged by operation at excessively high fuel utilization > 91%. It was rebuilt and returned to Rokko Island. This module B2 operated for 1843 hours on PNG; shutdown was cuased by air supply failure. After a new blower and motor were installed July 1993, the system was restarted August 5, 1993 and operated continuously until November 10, 1993, when an automatic shutdown was induced as part of a MITI licensing inspection. After restart, the unit passed 6000 hours of operation on desulfurized PNG on January 25, 1994. Westinghouse`s future plans are outlined.

  13. Investigation of high temperature operation of proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Adjemian, Kevork Tro

    Proton exchange membrane fuel cells (PEMFCs) have garnered much attention in the media over the past years as they can provide a clean, environmentally friendly alternative to internal combustion engines. PEMFCs also have the flexibility to operate on many different types of fuels, thereby diminishing our reliance on foreign oil. PEMFCs, however, suffer from many drawbacks which need to be overcome before mass production becomes viable. One drawback is the expense of the fuel cell system, costing several times more than existing technologies. Another problem is that if the fuel cell is running on reformed fuels, trace amounts of carbon monoxide (10 ppm) in the hydrogen gas stream will completely poison the anode electrocatalyst, killing the PEMFC. Also, as a lot of waste heat is generated, a very elaborate cooling system needs to be used, making the overall system more expensive and complex. A possible solution to both the carbon monoxide poisoning and thermal management of a PEMFC is to elevate its operating temperature above 100°C. Unfortunately, current state-of-the-art electrolytes used in PEMFCs, i.e. Nafion 115, rely on water for the conduction of protons and by elevating the temperature, water loss occurs due to evaporation resulting in inadequate PEMFC performance. This thesis delves into the modification of Nafion and similar electrolytes to permit PEMFC operation above 100°C. This was accomplished by impregnating the pores of the Nafion with hydrophilic inorganic materials-silicon oxide via sol-gel processing and various inorganic particles. By performing these modifications to the various electrolytes, several composite membranes performed exceptionally well at an operating temperature of 130°C and demonstrated carbon monoxide tolerance of up to 500 ppm. In addition, a theory on how these materials help improve the water management characteristics of Nafion was developed, laying the foundation for the development of a completely novel membrane to

  14. Special considerations on operating a fuel cell power plant using natural gas with marginal heating value

    SciTech Connect

    Moses, L. Ng; Chien-Liang Lin; Ya-Tang Cheng

    1996-12-31

    In realizing new power generation technologies in Taiwan, a phosphoric acid fuel cell power plant (model PC2513, ONSI Corporation) has been installed in the premises of the Power Research Institute of the Taiwan Power Company in Taipei County of Taiwan. The pipeline gas supplying to the site of this power plant has a high percentage of carbon dioxide and thus a slightly lower heating value than that specified by the manufacturer. Because of the lowering of heating value of input gas, the highest Output power from the power plant is understandably less than the rated power of 200 kW designed. Further, the transient response of the power plant as interrupted from the Grid is also affected. Since this gas is also the pipeline gas supplying to the heavily populated Taipei Municipal area, it is conceivable that the success of the operations of fuel cells using this fuel is of vital importance to the promotion of the use of this power generation technology in Taiwan. Hence, experiments were set up to assess the feasibility of this fuel cell power plant using the existing pipeline gas in this part of Taiwan where fuel cells would most likely find useful.

  15. Operating proton exchange membrane fuel cells without external humidification of the reactant gases

    SciTech Connect

    Buechi, F.N.; Srinivasan, S.

    1997-08-01

    Operation of proton exchange membrane fuel cells (PEMFC) without external humidification of the reactant gases is advantageous for the PEMFC system, because it eliminates the need for a gas-humidification subsystem. The gas-humidification subsystem is a burden in the fuel cell system with respect to weight, complexity, cost, and parasitic power. A model for the operation of PEMFC with internal humidification of the gases is presented and the range of operating conditions for a PEMFC using dry H{sub 2}/air was investigated. The model predicts that dry air, entering at the cathode, can be fully internally humidified by the water produced by the electrochemical reaction at temperatures up to 70 C. This model was experimentally verified for cell temperatures up to 60 C by long-term operation of a PEMFC with dry gases for up to 1,800 h. The current densities, obtained at 0.6 V, were 20 to 40% lower than those measured when both gases were humidified. The water distribution in the cell, while operating with dry gases, was investigated by measuring the amount of product water on the anode and cathode sides. It was found that the back-diffusion of product water to the anode is the dominant process for water management in the cell over a wide range of operating conditions. The dominating water back-diffusion also allows internal humidification of the hydrogen reactant and prevents drying out of the anode.

  16. Depression of hydrogen evolution during operation of a direct borohydride fuel cell

    NASA Astrophysics Data System (ADS)

    Li, Z. P.; Liu, B. H.; Zhu, J. K.; Suda, S.

    Hydrogen evolution from the anode usually occurs during operation of a Direct Borohydride Fuel Cell (DBFC). This would not only decrease the fuel utilization, but also lower the cell performance because hydrogen bubbles would hinder ion movement in the anolyte. In this paper, the hydrogen evolution behavior is investigated based on relations of hydrogen evolution rates versus operation currents of the DBFC. The effects of anode modification on the hydrogen evolution rate and the cell performance were investigated. It was found that hydrogen evolution was depressed by adding Pd, Ag and Au catalysts in the anode. Coating a thin Nafion film on the catalyst surfaces was another effective way to decrease the hydrogen evolution rate. Depression of the hydrogen evolution and improvement of the DBFC performance can be achieved by adding carbon supported Pd in Ni anode with a suitable content of Nafion. However, too much Nafion in the anode would degrade the DBFC performance.

  17. Operation of a solid oxide fuel cell on biodiesel with a partial oxidation reformer

    SciTech Connect

    Siefert, N, Shekhawat, D.; Gemmen, R.; Berry, D.

    2010-01-01

    The National Energy Technology Laboratory’s Office of Research & Development (NETL/ORD) has successfully demonstrated the operation of a solid oxide fuel cell (SOFC) using reformed biodiesel. The biodiesel for the project was produced and characterized by West Virginia State University (WVSU). This project had two main aspects: 1) demonstrate a catalyst formulation on monolith for biodiesel fuel reforming; and 2) establish SOFC stack test stand capabilities. Both aspects have been completed successfully. For the first aspect, in–house patented catalyst specifications were developed, fabricated and tested. Parametric reforming studies of biofuels provided data on fuel composition, catalyst degradation, syngas composition, and operating parameters required for successful reforming and integration with the SOFC test stand. For the second aspect, a stack test fixture (STF) for standardized testing, developed by Pacific Northwest National Laboratory (PNNL) and Lawrence Berkeley National Laboratory (LBNL) for the Solid Energy Conversion Alliance (SECA) Program, was engineered and constructed at NETL. To facilitate the demonstration of the STF, NETL employed H.C. Starck Ceramics GmbH & Co. (Germany) anode supported solid oxide cells. In addition, anode supported cells, SS441 end plates, and cell frames were transferred from PNNL to NETL. The stack assembly and conditioning procedures, including stack welding and sealing, contact paste application, binder burn-out, seal-setting, hot standby, and other stack assembly and conditioning methods were transferred to NETL. In the future, fuel cell stacks provided by SECA or other developers could be tested at the STF to validate SOFC performance on various fuels. The STF operated on hydrogen for over 1000 hrs before switching over to reformed biodiesel for 100 hrs of operation. Combining these first two aspects led to demonstrating the biodiesel syngas in the STF. A reformer was built and used to convert 0.5 ml/min of

  18. Operation of the 25 kW NASA Lewis Solar Regenerative Fuel Cell Testbed Facility

    SciTech Connect

    Voecks, G.E.; Rohatgi, N.K.; Moore, S.H.

    1996-12-31

    Assembly of the NASA Lewis Research Center Solar Regenerative Fuel Cell Testbed Facility has recently been completed and system testing is in progress. This facility includes the integration of 50 kW photovoltaic solar cell arrays, a 25 kW proton exchange membrane (PEM) electrolysis unit, four 5 kW PEM fuel cells, high pressure hydrogen and oxygen storage vessels, high purity water storage containers, and computer monitoring, control and data acquisition. The purpose of this facility is multi-faceted, but was originally intended to serve as a testbed for evaluating a closed-loop powerplant for future NASA extended life support operations, such as a Lunar outpost, and also as a terrestrial powerplant example for remote or continuous back-up support operations. The fuel cell and electrolyzer subsystems design and assembly were conducted by the Jet Propulsion Laboratory (JPL), the photovoltaic arrays and electrical interconnect to the electrolyzer were provided by the US Navy/China Lake Naval Weapons Center, and testing and operations are being carried out by JPL.

  19. An efficient approach to cathode operational parameters optimization for microbial fuel cell using response surface methodology

    PubMed Central

    2014-01-01

    Background In the recent study, optimum operational conditions of cathode compartment of microbial fuel cell were determined by using Response Surface Methodology (RSM) with a central composite design to maximize power density and COD removal. Methods The interactive effects of parameters such as, pH, buffer concentration and ionic strength on power density and COD removal were evaluated in two-chamber microbial batch-mode fuel cell. Results Power density and COD removal for optimal conditions (pH of 6.75, buffer concentration of 0.177 M and ionic strength of cathode chamber of 4.69 mM) improve by 17 and 5%, respectively, in comparison with normal conditions (pH of 7, buffer concentration of 0.1 M and ionic strength of 2.5 mM). Conclusions In conclusion, results verify that response surface methodology could successfully determine cathode chamber optimum operational conditions. PMID:24423039

  20. Durability of Membrane Electrode Assemblies (MEAs) in PEM Fuel Cells Operated on Pure Hydrogen and Oxygen

    NASA Technical Reports Server (NTRS)

    Stanic, Vesna; Braun, James; Hoberecht, Mark

    2003-01-01

    Proton exchange membrane (PEM) fuel cells are energy sources that have the potential to replace alkaline fuel cells for space programs. Broad power ranges, high peak-to-nominal power capabilities, low maintenance costs, and the promise of increased life are the major advantages of PEM technology in comparison to alkaline technology. The probability of PEM fuel cells replacing alkaline fuel cells for space applications will increase if the promise of increased life is verified by achieving a minimum of 10,000 hours of operating life. Durability plays an important role in the process of evaluation and selection of MEAs for Teledyne s Phase I contract with the NASA Glenn Research Center entitled Proton Exchange Membrane Fuel cell (PEMFC) Power Plant Technology Development for 2nd Generation Reusable Launch Vehicles (RLVs). For this contract, MEAs that are typically used for H2/air operation were selected as potential candidates for H2/O2 PEM fuel cells because their catalysts have properties suitable for O2 operation. They were purchased from several well-established MEA manufacturers who are world leaders in the manufacturing of diverse products and have committed extensive resources in an attempt to develop and fully commercialize MEA technology. A total of twelve MEAs used in H2/air operation were initially identified from these manufacturers. Based on the manufacturers specifications, nine of these were selected for evaluation. Since 10,000 hours is almost equivalent to 14 months, it was not possible to perform continuous testing with each MEA selected during Phase I of the contract. Because of the lack of time, a screening test on each MEA was performed for 400 hours under accelerated test conditions. The major criterion for an MEA pass or fail of the screening test was the gas crossover rate. If the gas crossover rate was higher than the membrane intrinsic permeability after 400 hours of testing, it was considered that the MEA had failed the test. Three types of

  1. Why solid oxide cells can be reversibly operated in solid oxide electrolysis cell and fuel cell modes?

    PubMed

    Chen, Kongfa; Liu, Shu-Sheng; Ai, Na; Koyama, Michihisa; Jiang, San Ping

    2015-12-14

    High temperature solid oxide cells (SOCs) are attractive for storage and regeneration of renewable energy by operating reversibly in solid oxide electrolysis cell (SOEC) and solid oxide fuel cell (SOFC) modes. However, the stability of SOCs, particularly the deterioration of the performance of oxygen electrodes in the SOEC operation mode, is the most critical issue in the development of high performance and durable SOCs. In this study, we investigate in detail the electrochemical activity and stability of La0.8Sr0.2MnO3 (LSM) oxygen electrodes in cyclic SOEC and SOFC modes. The results show that the deterioration of LSM oxygen electrodes caused by anodic polarization can be partially or completely recovered by subsequent cathodic polarization. Using in situ assembled LSM electrodes without pre-sintering, we demonstrate that the deteriorated LSM/YSZ interface can be repaired and regenerated by operating the cells under cathodic polarization conditions. This study for the first time establishes the foundation for the development of truly reversible and stable SOCs for hydrogen fuel production and electricity generation in cyclic SOEC and SOFC operation modes.

  2. Mathematical model of a plate fin heat exchanger operating under solid oxide fuel cell working conditions

    NASA Astrophysics Data System (ADS)

    Kaniowski, Robert; Poniewski, Mieczysław

    2013-12-01

    Heat exchangers of different types find application in power systems based on solid oxide fuel cells (SOFC). Compact plate fin heat exchangers are typically found to perfectly fit systems with power output under 5 kWel. Micro-combined heat and power (micro-CHP) units with solid oxide fuel cells can exhibit high electrical and overall efficiencies, exceeding 85%, respectively. These values can be achieved only when high thermal integration of a system is assured. Selection and sizing of heat exchangers play a crucial role and should be done with caution. Moreover, performance of heat exchangers under variable operating conditions can strongly influence efficiency of the complete system. For that reason, it becomes important to develop high fidelity mathematical models allowing evaluation of heat exchangers under modified operating conditions, in high temperature regimes. Prediction of pressure and temperatures drops at the exit of cold and hot sides are important for system-level studies. Paper presents dedicated mathematical model used for evaluation of a plate fin heat exchanger, operating as a part of micro-CHP unit with solid oxide fuel cells.

  3. The operation of a solid polymer fuel cell - A parametric model

    NASA Astrophysics Data System (ADS)

    Amphlett, J. C.; Farahani, M.; Mann, R. F.; Peppley, B. A.; Roberge, P. R.

    An empirical model of the performance of the Ballard Power Systems Mark IV fuel cell is developed. The model contains seven parameters, each one associated with a specific operating variable. Cell voltages at 400 ASF were measured for pressures from 15 to 35 psig; temperatures of 60, 70, and 80 C; excess hydrogen feed from 5-25 percent; excess oxygen feed from 50-150 percent; and oxygen concentrations in nitrogen from 21-100 percent by volume. Polarization curves were also measured for current densities from 200-500 ASF. Using these data, a set of coefficients was determined to give the best prediction of single-cell performance. The model was then tested against data from a 12-cell stack of similar design and found to predict variation in cell voltage to within 5 percent. The model can be used to predict the electrochemical efficiency of the fuel cell in the neighborhood of a baseline condition. The utility of the model is in developing a simulation of an integrated methanol reformer/fuel cell power generating system.

  4. In situ neutron imaging technique for evaluation of water management systems in operating PEM fuel cells

    NASA Astrophysics Data System (ADS)

    Satija, R.; Jacobson, D. L.; Arif, M.; Werner, S. A.

    This paper explores the method of neutron imaging as an experimental tool to perform in situ non-destructive analysis on an operating polymer electrolyte membrane hydrogen fuel cell. Neutrons are ideal for the imaging of hydrogen fuel cells because of their sensitivity to hydrogen-containing compounds such as water. This research focused on using imaging techniques to develop methods for testing and evaluating the water management system of a fuel cell. A real-time radiography dataset consisting of 1000 images at 2-s intervals was used to create a movie which showed water production, transport, and removal throughout the cell. This dataset was also analyzed to quantify and calculate the amount of water present in the cell at any time and masking techniques were used to differentiate between water in the cell flow channels and in the gas diffusion layer. Additionally, a tomography dataset allowed for the creation of a digital 3-dimensional (3-D) reconstruction of the dry cell which can be analyzed for structural defects.

  5. Performance and durability of PEM fuel cells operated at sub-freezing temperatures

    SciTech Connect

    Mukundan, Rangachary; Davey, John R; Lujan, Roger W; Spendelow, Jacob S

    2008-01-01

    The durability of polymer electrolyte membrane (PEM) fuel cells operated at sub-freezing temperatures has received increasing attention in recent years. The Department of Energy's PEM fuel cell stack technical targets for the year 2010 include unassisted start-up from -40 {sup o}C and startup from -20 {sup o}C ambient in as low as 30 seconds with < 5 MJ energy consumption. Moreover, the sub-freezing operations should not have any impact on acieving other technical targets including 5000 hours durability. The effect of MEA preparation on the performance of single-PEM fuel cells operated at sub-freezing temperatures is presented. The cell performance and durability are dependent on the MEA and are probably influenced by the porosity of the catalyst layers. When a cell is operated isothermally at -10 {sup o}C in constant current mode, the voltage gradually decreases over time and eventually drops to zero. AC impedance analysis indicated that the rate of voltage loss is initially due to an increase in the charge transfer resistance and is gradual. After a period, the rate of decay accelerates rapidly due to mass transport limitations at the catalyst and/or gas diffusion layers. The high frequency resistance also increases over time during the isothermal operation at sub-freezing temperatures and was a function of the initial membrane water content. LANL prepared MEAs showed very little loss in the catalyst surface area with multiple sub-freezing operations, whereas the commercial MEAs exhibited significant loss in cathode surface area with the anode being unaffected. These results indicate that catalyst layer ice formation is influenced strongly by the MEA and is responsible for the long-term degradation of fuel cells operated at sub-freezing temperatures. This ice formation was monitored using neutron radiography and was found to be concentrated near cell edges at the flow field turns. The water distribution also indicated that ice may be forming mainly in the GDLs at

  6. Analysis, operation and maintenance of a fuel cell/battery series-hybrid bus for urban transit applications

    NASA Astrophysics Data System (ADS)

    Bubna, Piyush; Brunner, Doug; Gangloff, John J.; Advani, Suresh G.; Prasad, Ajay K.

    The fuel cell hybrid bus (FCHB) program was initiated at the University of Delaware in 2005 to demonstrate the viability of fuel cell vehicles for transit applications and to conduct research and development to facilitate the path towards their eventual commercialization. Unlike other fuel cell bus programs, the University of Delaware's FCHB design features a battery-heavy hybrid which offers multiple advantages in terms of cost, performance and durability. The current fuel cell hybrid bus is driven on a regular transit route at the University of Delaware. The paper describes the baseline specifications of the bus with a focus on the fuel cell and the balance of plant. The fuel cell/battery series-hybrid design is well suited for urban transit routes and provides key operational advantages such as hydrogen fuel economy, efficient use of the fuel cell for battery recharging, and regenerative braking. The bus is equipped with a variety of sensors including a custom-designed cell voltage monitoring system which provide a good understanding of bus performance under normal operation. Real-time data collection and analysis have yielded key insights for fuel cell bus design optimization. Results presented here illustrate the complex flow of energy within the various subsystems of the fuel cell hybrid bus. A description of maintenance events has been included to highlight the issues that arise during general operation. The paper also describes several modifications that will facilitate design improvements in future versions of the bus. Overall, the fuel cell hybrid bus demonstrates the viability of fuel cells for urban transit applications in real world conditions.

  7. Effects of Operating Conditions on Internal Resistances in Enzyme Fuel Cells Studied via Electrochemical Impedance Spectroscopy

    SciTech Connect

    Aaron, D; Borole, Abhijeet P; Yiacoumi, Sotira; Tsouris, Costas

    2012-01-01

    Enzyme fuel cells (EFCs) offer some advantages over traditional precious-metal-catalyzed fuel cells, such as polymer electrolyte membrane fuel cells (PEMFCs). However, EFCs exhibit far less power output than PEMFCs and have relatively short life spans before materials must be replaced. In this work, electrochemical impedance spectroscopy (EIS) is used to analyze the internal resistances throughout the EFC at a variety of operating conditions. EIS analysis is focused primarily on the resistances of the anode, solution/membrane, and cathode. Increased enzyme loading results in improved power output and reductions in internal resistance. Conditions are identified for which enzyme loading does not limit the EFC performance. EIS experiments are also reported for EFCs operated continuously for 2 days; power output declines sharply over time, while all internal resistances increase. Drying of the cathode and enzyme/mediator degradation are believed to have contributed to this behavior. Finally, experiments are performed at varying air-humidification temperatures. Little effect on internal resistances or power output is observed. However, it is anticipated that increased air humidification can improve longevity by delivering more water to the cathode. Improvements to the enzymatic cathode are needed for EFC development. These improvements need to focus on improving transport rather than increasing enzyme loading.

  8. Improving the operation of a fuel-cell power unit with supervision control - A simulation study

    NASA Astrophysics Data System (ADS)

    Pregelj, Boštjan; Vrečko, Darko; Jovan, Vladimir

    Polymer electrolyte membrane fuel cells are proving to be a clean and efficient source of energy. Nowadays, extensive research efforts are being focused on bringing this technology to everyday use. An important aspect when integrating fuel cells in practical applications is their ability to respond to load demand. With respect to this, due to their complex internal dynamics, fuel cells belong to the group of more slowly responding sources. In order to make them more generally applicative they are often connected with a battery or a super-capacitor via a power converter to form a hybrid power source. A control algorithm, designed for such a system, represents an interesting challenge: it has to adapt to varying working conditions and operate optimally in terms of efficiency and reliability, while minimizing any impacts on the degradation of the components. Here, we present an approach using supervisory control automaton that switches between the system's operational modes and sets the references for the lower-level control loops. The evaluation of the efficiency and degradation is carried out in a simulation using a model of the widely used 1.2-kW Ballard Nexa power module.

  9. Integrated anode structure for passive direct methanol fuel cells with neat methanol operation

    NASA Astrophysics Data System (ADS)

    Wu, Huijuan; Zhang, Haifeng; Chen, Peng; Guo, Jing; Yuan, Ting; Zheng, Junwei; Yang, Hui

    2014-02-01

    A microporous titanium plate based integrated anode structure (Ti-IAS) suitable for passive direct methanol fuel cells (DMFCs) fueled with neat methanol is reported. This anode structure incorporates a porous titanium plate as a methanol mass transfer barrier and current collector, pervaporation film for passively vaporizing methanol, vaporous methanol cavity for evenly distributing fuel, and channels for carbon dioxide venting. With the effective control of methanol delivery rate, the Ti-IAS based DMFC allows the direct use of neat methanol as the fuel source. In the meantime, the required water for methanol-oxidation reaction at the anode can also be fully recovered from the cathode with the help of the highly hydrophobic microporous layer in the cathode. DMFCs incorporating this new anode structure exhibit a power density as high as 40 mW cm-2 and a high volumetric energy density of 489 Wh L-1 operating with neat methanol and at 25 °C. Importantly, no obvious performance degradation of the passive DMFC system is observed after more than 90 h of continuous operation. The experimental results reveal that the compact DMFC based on the Ti-IAS exhibits a substantial potential as power sources for portable applications.

  10. Fuel Cell Demonstration Program

    SciTech Connect

    Gerald Brun

    2006-09-15

    In an effort to promote clean energy projects and aid in the commercialization of new fuel cell technologies the Long Island Power Authority (LIPA) initiated a Fuel Cell Demonstration Program in 1999 with six month deployments of Proton Exchange Membrane (PEM) non-commercial Beta model systems at partnering sites throughout Long Island. These projects facilitated significant developments in the technology, providing operating experience that allowed the manufacturer to produce fuel cells that were half the size of the Beta units and suitable for outdoor installations. In 2001, LIPA embarked on a large-scale effort to identify and develop measures that could improve the reliability and performance of future fuel cell technologies for electric utility applications and the concept to establish a fuel cell farm (Farm) of 75 units was developed. By the end of October of 2001, 75 Lorax 2.0 fuel cells had been installed at the West Babylon substation on Long Island, making it the first fuel cell demonstration of its kind and size anywhere in the world at the time. Designed to help LIPA study the feasibility of using fuel cells to operate in parallel with LIPA's electric grid system, the Farm operated 120 fuel cells over its lifetime of over 3 years including 3 generations of Plug Power fuel cells (Lorax 2.0, Lorax 3.0, Lorax 4.5). Of these 120 fuel cells, 20 Lorax 3.0 units operated under this Award from June 2002 to September 2004. In parallel with the operation of the Farm, LIPA recruited government and commercial/industrial customers to demonstrate fuel cells as on-site distributed generation. From December 2002 to February 2005, 17 fuel cells were tested and monitored at various customer sites throughout Long Island. The 37 fuel cells operated under this Award produced a total of 712,635 kWh. As fuel cell technology became more mature, performance improvements included a 1% increase in system efficiency. Including equipment, design, fuel, maintenance, installation

  11. Novel microbial fuel cell design to operate with different wastewaters simultaneously.

    PubMed

    Mathuriya, Abhilasha Singh

    2016-04-01

    A novel single cathode chamber and multiple anode chamber microbial fuel cell design (MAC-MFC) was developed by incorporating multiple anode chambers into a single unit and its performance was checked. During 60 days of operation, performance of MAC-MFC was assessed and compared with standard single anode/cathode chamber microbial fuel cell (SC-MFC). The tests showed that MAC-MFC generated stable and higher power outputs compared with SC-MFC and each anode chamber contributed efficiently. Further, MAC-MFCs were incorporated with different wastewaters in different anode chambers and their behavior in MFC performance was observed. MAC-MFC efficiently treated multiple wastewaters simultaneously at low cost and small space, which claims its candidature for future possible scale-up applications.

  12. Development and operation of gold and cobalt oxide nanoparticles containing polypropylene based enzymatic fuel cell for renewable fuels.

    PubMed

    Kilic, Muhammet Samet; Korkut, Seyda; Hazer, Baki; Erhan, Elif

    2014-11-15

    Newly synthesized gold and cobalt oxide nanoparticle embedded Polypropylene-g-Polyethylene glycol was used for a compartment-less enzymatic fuel cell. Glucose oxidase and bilirubin oxidase were selected as anodic and cathodic enzymes, respectively. Electrode fabrication and EFC operation parameters were optimized to achieve high power output. Maximum power density of 23.5 µW cm(-2) was generated at a cell voltage of +560 mV vs Ag/AgCl, in 100mM PBS pH 7.4 with the addition of 20mM of synthetic glucose solution. 20 µg of polymer amount with 185 µg of glucose oxidase and 356 µg of bilirubin oxidase was sufficient to get maximum performance. The working electrodes could harvest glucose, produced during photosynthesis reaction of Carpobrotus Acinaciformis plant, and readily found in real domestic wastewater of Zonguldak City in Turkey. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. CERDEC Fuel Cell Team: Military Transitions for Soldier Fuel Cells

    DTIC Science & Technology

    2008-10-27

    Fuel Cell (DMFC) (PEO Soldier) Samsung: 20W DMFC (CRADA) General Atomics & Jadoo: 50W Ammonia Borane Fueled PEMFC Current Fuel Cell Team Efforts...Continued Ardica: 20W Wearable PEMFC operating on Chemical Hydrides Spectrum Brands w/ Rayovac: Hydrogen Generators and Alkaline Fuel Cells for AA...100W Ammonia Borane fueled PEMFC Ultralife: 150W sodium borohydride fueled PEMFC Protonex: 250W RMFC and Power Manager (ARO) NanoDynamics: 250W SOFC

  14. Fuel cell-fuel cell hybrid system

    DOEpatents

    Geisbrecht, Rodney A.; Williams, Mark C.

    2003-09-23

    A device for converting chemical energy to electricity is provided, the device comprising a high temperature fuel cell with the ability for partially oxidizing and completely reforming fuel, and a low temperature fuel cell juxtaposed to said high temperature fuel cell so as to utilize remaining reformed fuel from the high temperature fuel cell. Also provided is a method for producing electricity comprising directing fuel to a first fuel cell, completely oxidizing a first portion of the fuel and partially oxidizing a second portion of the fuel, directing the second fuel portion to a second fuel cell, allowing the first fuel cell to utilize the first portion of the fuel to produce electricity; and allowing the second fuel cell to utilize the second portion of the fuel to produce electricity.

  15. Energy balance affected by electrolyte recirculation and operating modes in microbial fuel cells.

    PubMed

    Jacobson, Kyle S; Kelly, Patrick T; He, Zhen

    2015-03-01

    Energy recovery and consumption in a microbial fuel cell (MFC) can be significantly affected by the operating conditions. This study investigated the effects of electrolyte recirculation and operation mode (continuous vs sequence batch reactor) on the energy balance in a tubular MFC. It was found that decreasing the anolyte recirculation also decreased the energy recovery. Because of the open environment of the cathode electrode, the catholyte recirculation consumed 10 to 50 times more energy than the anolyte recirculation, and resulted in negative energy balances despite the reduction of the anolyte recirculation. Reducing the catholyte recirculation to 20% led to a positive energy balance of 0.0288 kWh m(-3). The MFC operated as a sequence batch reactor generated less energy and had a lower energy balance than the one with continuous operation. Those results encourage the further development of MFC technology to achieve neutral or even positive energy output.

  16. Direct operation of Ag-based anode solid oxide fuel cells on propane

    NASA Astrophysics Data System (ADS)

    Zhang, Yapeng; Yu, Fangyong; Wang, Xiaoqiang; Zhou, Qian; Liu, Jiang; Liu, Meilin

    2017-10-01

    A cermet of sliver and gadolinium-doped ceria (GDC) is investigated as the anode material of solid oxide fuel cells (SOFCs). The SOFCs are operated with hydrogen and dry propane as the fuel and ambient air as the oxidant. Their electrochemical and durability performances are tested and compared to those of SOFCs with conventional Ni-GDC anode. Experimental results show that performances of the SOFCs, respectively with Ag-GDC and Ni-GDC anode, are similar when operated on hydrogen, while quite different on propane. The open circuit voltage (OCV) of a SOFC with Ag-GDC anode is stable at ∼1 V while that with Ni-GDC anode continuously drops from the initial 1.2 V-0.85 V in 140 min. A SOFC with Ag-GDC anode has been stably operated on propane at a constant current density of 103 mA cm-2 for more than 160 h while that with Ni-GDC anode for only 50 h. SEM examination shows Ni-GDC anode is destroyed by carbon deposition during operation on propane, while Ag-GDC anode is well conserved and has a carbon layer, with some breakages, built on its surface. Mechanisms of the stable operation of SOFCs with Ag-GDC anode on dry propane is investigated and analyzed.

  17. AuPd/polyaniline as the anode in an ethylene glycol microfluidic fuel cell operated at room temperature.

    PubMed

    Arjona, N; Palacios, A; Moreno-Zuria, A; Guerra-Balcázar, M; Ledesma-García, J; Arriaga, L G

    2014-08-04

    AuPd/polyaniline was used for the first time, for ethylene glycol (EG) electrooxidation in a novel microfluidic fuel cell (MFC) operated at room temperature. The device exhibits high electrocatalytic performance and stability for the conversion of cheap and fully available EG as fuel.

  18. Fuel cells for commercial energy

    NASA Astrophysics Data System (ADS)

    Huppmann, Gerhard; Weisse, Eckart; Bischoff, Manfred

    1990-04-01

    The development of various types of fuel cells is described. Advantges and drawbacks are considered for alkaline fuel cells, phosphoric acid fuel cells, and molten carbonate fuel cells. It is shown that their modular construction is particularly adapted to power heat systems. A comparison which is largely in favor of fuel cells, is made between coal, oil, natural gas power stations, and fuel cells. Safety risks in operation are also compared with those of conventional power stations. Fuel cells are particularly suited for dwellings, shopping centers, swimming pools, other sporting installations, and research facilities, whose high current and heat requirements can be covered by power heat coupling.

  19. Environmental assessment of the 40 kilowatt fuel cell system field test operation

    NASA Technical Reports Server (NTRS)

    Bollenbacher, G.

    1982-01-01

    This environmental assessment examines the potential environmental consequences, both adverse and beneficial, of the 40 kW fuel cell system system field test operation. The assessment is of necessity generic in nature since actual test sites were not selected. This assessment provides the basis for determining the need for an environmental impact statement. In addition, this assessment provides siting criteria to avoid or minimize negative environmental impacts and standards for determining candidate test sites, if any, for which site specific assessments may be required.

  20. Durability of Polymer Electrolyte Membrane Fuel Cells Operated at Subfreezing Temperatures

    DOE PAGES

    Macauley, Natalia; Lujan, Roger W.; Spernjak, Dusan; ...

    2016-09-15

    The structure, composition, and interfaces of membrane electrode assemblies (MEA) and gas-diffusion layers (GDLs) have a significant effect on the performance of single-proton-exchange-membrane (PEM) fuel cells operated isothermally at subfreezing temperatures. During isothermal constant-current operation at subfreezing temperatures, water forming at the cathode initially hydrates the membrane, then forms ice in the catalyst layer and/or GDL. This ice formation results in a gradual decay in voltage. High-frequency resistance initially decreases due to an increase in membrane water content and then increases over time as the contact resistance increases. The water/ice holding capacity of a fuel cell decreases with decreasing subfreezingmore » temperature (-10°C vs. -20°C vs. -30°C) and increasing current density (0.02 A cm-2 vs. 0.04 A cm-2). Ice formation monitored using in-situ high-resolution neutron radiography indicated that the ice was concentrated near the cathode catalyst layer at low operating temperatures (≈-20°C) and high current densities (0.04 A cm-2). Significant ice formation was also observed in the GDLs at higher subfreezing temperatures (≈-10°C) and lower current densities (0.02 A cm-2). These results are in good agreement with the long-term durability observations that show more severe degradation at lower temperatures (-20°C and -30°C).« less

  1. A selective electrocatalyst–based direct methanol fuel cell operated at high concentrations of methanol

    PubMed Central

    Feng, Yan; Liu, Hui; Yang, Jun

    2017-01-01

    Owing to the serious crossover of methanol from the anode to the cathode through the polymer electrolyte membrane, direct methanol fuel cells (DMFCs) usually use dilute methanol solutions as fuel. However, the use of high-concentration methanol is highly demanded to improve the energy density of a DMFC system. Instead of the conventional strategies (for example, improving the fuel-feed system, membrane development, modification of electrode, and water management), we demonstrate the use of selective electrocatalysts to run a DMFC at high concentrations of methanol. In particular, at an operating temperature of 80°C, the as-fabricated DMFC with core-shell-shell Au@Ag2S@Pt nanocomposites at the anode and core-shell Au@Pd nanoparticles at the cathode produces a maximum power density of 89.7 mW cm−2 at a methanol feed concentration of 10 M and maintains good performance at a methanol concentration of up to 15 M. The high selectivity of the electrocatalysts achieved through structural construction accounts for the successful operation of the DMFC at high concentrations of methanol. PMID:28695199

  2. A selective electrocatalyst-based direct methanol fuel cell operated at high concentrations of methanol.

    PubMed

    Feng, Yan; Liu, Hui; Yang, Jun

    2017-06-01

    Owing to the serious crossover of methanol from the anode to the cathode through the polymer electrolyte membrane, direct methanol fuel cells (DMFCs) usually use dilute methanol solutions as fuel. However, the use of high-concentration methanol is highly demanded to improve the energy density of a DMFC system. Instead of the conventional strategies (for example, improving the fuel-feed system, membrane development, modification of electrode, and water management), we demonstrate the use of selective electrocatalysts to run a DMFC at high concentrations of methanol. In particular, at an operating temperature of 80°C, the as-fabricated DMFC with core-shell-shell Au@Ag2S@Pt nanocomposites at the anode and core-shell Au@Pd nanoparticles at the cathode produces a maximum power density of 89.7 mW cm(-2) at a methanol feed concentration of 10 M and maintains good performance at a methanol concentration of up to 15 M. The high selectivity of the electrocatalysts achieved through structural construction accounts for the successful operation of the DMFC at high concentrations of methanol.

  3. Molten Carbonate Fuel Cell performance analysis varying cathode operating conditions for carbon capture applications

    NASA Astrophysics Data System (ADS)

    Audasso, Emilio; Barelli, Linda; Bidini, Gianni; Bosio, Barbara; Discepoli, Gabriele

    2017-04-01

    The results of a systematic experimental campaign to verify the impact of real operating conditions on the performance of a complete Molten Carbonate Fuel Cell (MCFC) are presented. In particular, the effects of ageing and composition of water, oxygen and carbon dioxide in the cathodic feeding stream are studied through the analysis of current-voltage curves and Electrochemical Impedance Spectroscopy (EIS). Based on a proposed equivalent electrical circuit model and a fitting procedure, a correlation is found among specific operating parameters and single EIS coefficients. The obtained results suggest a new performance monitoring approach to be applied to MCFC for diagnostic purpose. Particular attention is devoted to operating conditions characteristic of MCFC application as CO2 concentrators, which, by feeding the cathode with exhaust gases, is a promising route for efficient and cheap carbon capture.

  4. Durability and regeneration of activated carbon air-cathodes in long-term operated microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Zhang, Enren; Wang, Feng; Yu, Qingling; Scott, Keith; Wang, Xu; Diao, Guowang

    2017-08-01

    The performance of activated carbon catalyst in air-cathodes in microbial fuel cells was investigated over one year. A maximum power of 1722 mW m-2 was produced within the initial one-month microbial fuel cell operation. The air-cathodes produced a maximum power >1200 mW m-2 within six months, but gradually became a limiting factor for the power output in prolonged microbial fuel cell operation. The maximum power decreased by 55% when microbial fuel cells were operated over one year due to deterioration in activated carbon air-cathodes. While salt/biofilm removal from cathodes experiencing one-year operation increased a limiting performance enhancement in cathodes, a washing-drying-pressing procedure could restore the cathode performance to its original levels, although the performance restoration was temporary. Durable cathodes could be regenerated by re-pressing activated carbon catalyst, recovered from one year deteriorated air-cathodes, with new gas diffusion layer, resulting in ∼1800 mW m-2 of maximum power production. The present study indicated that activated carbon was an effective catalyst in microbial fuel cell cathodes, and could be recovered for reuse in long-term operated microbial fuel cells by simple methods.

  5. The use of experimental design to find the operating maximum power point of PEM fuel cells

    SciTech Connect

    Crăciunescu, Aurelian; Pătularu, Laurenţiu; Ciumbulea, Gloria; Olteanu, Valentin; Pitorac, Cristina; Drugan, Elena

    2015-03-10

    Proton Exchange Membrane (PEM) Fuel Cells are difficult to model due to their complex nonlinear nature. In this paper, the development of a PEM Fuel Cells mathematical model based on the Design of Experiment methodology is described. The Design of Experiment provides a very efficient methodology to obtain a mathematical model for the studied multivariable system with only a few experiments. The obtained results can be used for optimization and control of the PEM Fuel Cells systems.

  6. Numerical simulation of proton exchange membrane fuel cells at high operating temperature

    NASA Astrophysics Data System (ADS)

    Peng, Jie; Lee, Seung Jae

    A three-dimensional, single-phase, non-isothermal numerical model for proton exchange membrane (PEM) fuel cell at high operating temperature (T ≥ 393 K) was developed and implemented into a computational fluid dynamic (CFD) code. The model accounts for convective and diffusive transport and allows predicting the concentration of species. The heat generated from electrochemical reactions, entropic heat and ohmic heat arising from the electrolyte ionic resistance were considered. The heat transport model was coupled with the electrochemical and mass transport models. The product water was assumed to be vaporous and treated as ideal gas. Water transportation across the membrane was ignored because of its low water electro-osmosis drag force in the polymer polybenzimidazole (PBI) membrane. The results show that the thermal effects strongly affect the fuel cell performance. The current density increases with the increasing of operating temperature. In addition, numerical prediction reveals that the width and distribution of gas channel and current collector land area are key optimization parameters for the cell performance improvement.

  7. Organic fuel cells and fuel cell conducting sheets

    DOEpatents

    Masel, Richard I.; Ha, Su; Adams, Brian

    2007-10-16

    A passive direct organic fuel cell includes an organic fuel solution and is operative to produce at least 15 mW/cm.sup.2 when operating at room temperature. In additional aspects of the invention, fuel cells can include a gas remover configured to promote circulation of an organic fuel solution when gas passes through the solution, a modified carbon cloth, one or more sealants, and a replaceable fuel cartridge.

  8. Performance of solid oxide fuel cells operated with coal syngas provided directly from a gasification process

    SciTech Connect

    Hackett, Gregory A.; Gerdes, Kirk R.; Song, Xueyan; Chen, Yun; Shutthanandan, V.; Engelhard, Mark H.; Zhu, Zihua; Thevuthasan, Suntharampillai; Gemmen, Randall

    2012-09-15

    Solid oxide fuel cells (SOFCs) are presently being developed for gasification integrated power plants that generate electricity from coal at 50+% efficiency. The interaction of trace metals in coal syngas with the Ni-based SOFC anodes is being investigated through thermodynamic analyses and in laboratory experiments, but direct test data from coal syngas exposure are sparsely available. This research effort evaluates the significance of SOFC performance losses associated with exposure of a SOFC anode to direct coal syngas. SOFC specimen of industrially relevant composition are operated in a unique mobile test skid that was deployed to the research gasifier at the National Carbon Capture Center (NCCC) in Wilsonville, AL. The mobile test skid interfaces with a gasifier slipstream to deliver hot syngas (up to 300°C) directly to a parallel array of 12 button cell specimen, each of which possesses an active area of approximately 2 cm2. During the 500 hour test period, all twelve cells were monitored for performance at four discrete operating current densities, and all cells maintained contact with a data acquisition system. Of these twelve, nine demonstrated good performance throughout the test, while three of the cells were partially compromised. Degradation associated with the properly functioning cells was attributed to syngas exposure and trace material attack on the anode structure that was accelerated at increasing current densities. Cells that were operated at 0 and 125 mA/cm² degraded at 9.1 and 10.7% per 1000 hours, respectively, while cells operated at 250 and 375 mA/cm² degraded at 18.9 and 16.2% per 1000 hours, respectively. Post-trial spectroscopic analysis of the anodes showed carbon, sulfur, and phosphorus deposits; no secondary Ni-metal phases were found.

  9. Fuel dissipater for pressurized fuel cell generators

    DOEpatents

    Basel, Richard A.; King, John E.

    2003-11-04

    An apparatus and method are disclosed for eliminating the chemical energy of fuel remaining in a pressurized fuel cell generator (10) when the electrical power output of the fuel cell generator is terminated during transient operation, such as a shutdown; where, two electrically resistive elements (two of 28, 53, 54, 55) at least one of which is connected in parallel, in association with contactors (26, 57, 58, 59), a multi-point settable sensor relay (23) and a circuit breaker (24), are automatically connected across the fuel cell generator terminals (21, 22) at two or more contact points, in order to draw current, thereby depleting the fuel inventory in the generator.

  10. Use of wastewater treatment plant biogas for the operation of Solid Oxide Fuel Cells (SOFCs).

    PubMed

    Lackey, Jillian; Champagne, Pascale; Peppley, Brant

    2017-12-01

    Solid Oxide Fuel Cells (SOFCs) perform well on light hydrocarbon fuels, and the use of biogas derived from the anaerobic digestion (AD) of municipal wastewater sludges could provide an opportunity for the CH4 produced to be used as a renewable fuel. Greenhouse gas (GHG), NOx, SOx, and hydrocarbon pollutant emissions would also be reduced. In this study, SOFCs were operated on AD derived biogas. Initially, different H2 dilutions were tested (N2, Ar, CO2) to examine the performance of tubular SOFCs. With inert gases as diluents, a decrease in cell performance was observed, however, the use of CO2 led to a higher decrease in performance as it promoted the reverse water-gas shift (WGS) reaction, reducing the H2 partial pressure in the gas mixture. A model was developed to predict system efficiency and GHG emissions. A higher electrical system efficiency was noted for a steam:carbon ratio of 2 compared to 1 due to the increased H2 partial pressure in the reformate resulting from higher H2O concentration. Reductions in GHG emissions were estimated at 2400 tonnes CO2, 60 kg CH4 and 18 kg N2O. SOFCs were also tested using a simulated biogas reformate mixture (66.7% H2, 16.1% CO, 16.5% CO2, 0.7% N2, humidified to 2.3 or 20 mol% H2O). Higher humidification yielded better performance as the WGS reaction produced more H2 with additional H2O. It was concluded that AD-derived biogas, when cleaned to remove H2S, Si compounds, halides and other contaminants, could be reformed to provide a clean, renewable fuel for SOFCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Flow rate and humidification effects on a PEM fuel cell performance and operation

    NASA Astrophysics Data System (ADS)

    Guvelioglu, Galip H.; Stenger, Harvey G.

    A new algorithm is presented to integrate component balances along polymer electrolyte membrane fuel cell (PEMFC) channels to obtain three-dimensional results from a detailed two-dimensional finite element model. The analysis studies the cell performance at various hydrogen flow rates, air flow rates and humidification levels. This analysis shows that hydrogen and air flow rates and their relative humidity are critical to current density, membrane dry-out, and electrode flooding. Uniform current densities along the channels are known to be critical for thermal management and fuel cell life. This approach, of integrating a detailed two-dimensional across-the-channel model, is a promising method for fuel cell design due to its low computational cost compared to three-dimensional computational fluid dynamics models, its applicability to a wide range of fuel cell designs, and its ease of extending to fuel cell stack models.

  12. Handbook of fuel cell performance

    SciTech Connect

    Benjamin, T.G.; Camara, E.H.; Marianowski, L.G.

    1980-05-01

    The intent of this document is to provide a description of fuel cells, their performances and operating conditions, and the relationship between fuel processors and fuel cells. This information will enable fuel cell engineers to know which fuel processing schemes are most compatible with which fuel cells and to predict the performance of a fuel cell integrated with any fuel processor. The data and estimates presented are for the phosphoric acid and molten carbonate fuel cells because they are closer to commercialization than other types of fuel cells. Performance of the cells is shown as a function of operating temperature, pressure, fuel conversion (utilization), and oxidant utilization. The effect of oxidant composition (for example, air versus O/sub 2/) as well as fuel composition is examined because fuels provided by some of the more advanced fuel processing schemes such as coal conversion will contain varying amounts of H/sub 2/, CO, CO/sub 2/, CH/sub 4/, H/sub 2/O, and sulfur and nitrogen compounds. A brief description of fuel cells and their application to industrial, commercial, and residential power generation is given. The electrochemical aspects of fuel cells are reviewed. The phosphoric acid fuel cell is discussed, including how it is affected by operating conditions; and the molten carbonate fuel cell is discussed. The equations developed will help systems engineers to evaluate the application of the phosphoric acid and molten carbonate fuel cells to commercial, utility, and industrial power generation and waste heat utilization. A detailed discussion of fuel cell efficiency, and examples of fuel cell systems are given.

  13. Performance of solid oxide fuel cells operated with coal syngas provided directly from a gasification process

    NASA Astrophysics Data System (ADS)

    Hackett, Gregory A.; Gerdes, Kirk; Song, Xueyan; Chen, Yun; Shutthanandan, Vaithiyalingam; Engelhard, Mark; Zhu, Zihua; Thevuthasan, Suntharampillai; Gemmen, Randall

    2012-09-01

    Solid oxide fuel cells (SOFCs) are being developed for integrated gasification power plants that generate electricity from coal at 50+% efficiency. The interaction of trace metals in coal syngas with Ni-based SOFC anodes is being investigated through thermodynamic analyses and in laboratory experiments, but test data from direct coal syngas exposure are sparsely available. This effort evaluates the significance of performance losses associated with exposure to direct coal syngas. Specimen are operated in a unique mobile test skid that is deployed to the research gasifier at NCCC in Wilsonville, AL. The test skid interfaces with a gasifier slipstream to deliver hot syngas to a parallel array of twelve SOFCs. During the 500 h test period, all twelve cells are monitored for performance at four current densities. Degradation is attributed to syngas exposure and trace material attack on the anode structure that is accelerated at increasing current densities. Cells that are operated at 0 and 125 mA cm-2 degrade at 9.1 and 10.7% per 1000 h, respectively, while cells operated at 250 and 375 mA cm-2 degrade at 18.9 and 16.2% per 1000 h, respectively. Spectroscopic analysis of the anodes showed carbon, sulfur, and phosphorus deposits; no secondary Ni-metal phases were found.

  14. Influence of gadolinium doping on the structure and defects of ceria under fuel cell operating temperature

    NASA Astrophysics Data System (ADS)

    Acharya, S. A.; Gaikwad, V. M.; Sathe, V.; Kulkarni, S. K.

    2014-03-01

    Correlation between atomic positional shift, oxygen vacancy defects, and oxide ion conductivity in doped ceria system has been established in the gadolinium doped ceria system from X-ray diffraction (XRD) and Raman spectroscopy study at operating temperature (300-600 °C) of Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC). High temperature XRD data are used to quantify atomic positional shift from mean position with temperature. The Raman spectroscopy study shows additional vibration modes related to ordering of defect spaces (GdCe'-Vo••)* and (2GdCe'-Vo••)x generated due to association of oxygen vacancies and reduced cerium or dopant cations site (Gd3+), which disappear at 450 °C; indicating oxygen vacancies dissociation from the defect complex. The experimental evidences of cation-anion positional shifting and oxygen vacancies dissociation from defect complex in the IT-SOFC operating temperature are discussed to correlate with activation energy for ionic conductivity.

  15. Catalytic and electrochemical behaviour of solid oxide fuel cell operated with simulated-biogas mixtures

    NASA Astrophysics Data System (ADS)

    Dang-Long, T.; Quang-Tuyen, T.; Shiratori, Y.

    2016-06-01

    Being produced from organic matters of wastes (bio-wastes) through a fermentation process, biogas mainly composed of CH4 and CO2 and can be considered as a secondary energy carrier derived from solar energy. To generate electricity from biogas through the electrochemical process in fuel cells is a state-of-the-art technology possessing higher energy conversion efficiency without harmful emissions compared to combustion process in heat engines. Getting benefits from high operating temperature such as direct internal reforming ability and activation of electrochemical reactions to increase overall system efficiency, solid oxide fuel cell (SOFC) system operated with biogas becomes a promising candidate for distributed power generator for rural applications leading to reductions of environmental issues caused by greenhouse effects and bio-wastes. CO2 reforming of CH4 and electrochemical oxidation of the produced syngas (H2-CO mixture) are two main reaction processes within porous anode material of SOFC. Here catalytic and electrochemical behavior of Ni-ScSZ (scandia stabilized-zirconia) anode in the feed of CH4-CO2 mixtures as simulated-biogas at 800 °C were evaluated. The results showed that CO2 had strong influences on both reaction processes. The increase in CO2 partial pressure resulted in the decrease in anode overvoltage, although open-circuit voltage was dropped. Besides that, the simulation result based on a power-law model for equimolar CH4-CO2 mixture revealed that coking hazard could be suppressed along the fuel flow channel in both open-circuit and closed-circuit conditions.

  16. Catalytic and electrochemical behaviour of solid oxide fuel cell operated with simulated-biogas mixtures

    SciTech Connect

    Dang-Long, T.; Quang-Tuyen, T.; Shiratori, Y.

    2016-06-03

    Being produced from organic matters of wastes (bio-wastes) through a fermentation process, biogas mainly composed of CH{sub 4} and CO{sub 2} and can be considered as a secondary energy carrier derived from solar energy. To generate electricity from biogas through the electrochemical process in fuel cells is a state-of-the-art technology possessing higher energy conversion efficiency without harmful emissions compared to combustion process in heat engines. Getting benefits from high operating temperature such as direct internal reforming ability and activation of electrochemical reactions to increase overall system efficiency, solid oxide fuel cell (SOFC) system operated with biogas becomes a promising candidate for distributed power generator for rural applications leading to reductions of environmental issues caused by greenhouse effects and bio-wastes. CO{sub 2} reforming of CH{sub 4} and electrochemical oxidation of the produced syngas (H{sub 2}–CO mixture) are two main reaction processes within porous anode material of SOFC. Here catalytic and electrochemical behavior of Ni-ScSZ (scandia stabilized-zirconia) anode in the feed of CH{sub 4}–CO{sub 2} mixtures as simulated-biogas at 800 °C were evaluated. The results showed that CO{sub 2} had strong influences on both reaction processes. The increase in CO{sub 2} partial pressure resulted in the decrease in anode overvoltage, although open-circuit voltage was dropped. Besides that, the simulation result based on a power-law model for equimolar CH{sub 4}−CO{sub 2} mixture revealed that coking hazard could be suppressed along the fuel flow channel in both open-circuit and closed-circuit conditions.

  17. Fuel cell stack arrangements

    DOEpatents

    Kothmann, Richard E.; Somers, Edward V.

    1982-01-01

    Arrangements of stacks of fuel cells and ducts, for fuel cells operating with separate fuel, oxidant and coolant streams. An even number of stacks are arranged generally end-to-end in a loop. Ducts located at the juncture of consecutive stacks of the loop feed oxidant or fuel to or from the two consecutive stacks, each individual duct communicating with two stacks. A coolant fluid flows from outside the loop, into and through cooling channels of the stack, and is discharged into an enclosure duct formed within the loop by the stacks and seals at the junctures at the stacks.

  18. CAM operated fuel valve

    SciTech Connect

    Kelly, S.T.; Katchka, J.R.

    1991-09-03

    This patent describes improvement in a fuel control valve construction comprising a housing means having an inlet means adapted to be interconnected to a fuel source and a main outlet means adapted to be interconnected to a main burner means, the housing means having a main valve seat for interconnecting the inlet means with the main outlet means, the housing means having a movable main valve member for opening and closing the main valve seat, the housing means having a movable lever operatively associated with the main valve member and having a manually operable actuator means for controlling the operating positions of the lever, the lever having an intermediate cam follower portion and opposed ends disposed on each side of the cam follower portion with one end of the opposed ends being pivotally mounted to the housing means and with the other end of the opposed ends for operating the main valve member, the housing means having biasing means operatively interconnected to the lever to tend to pivot the lever in one direction that opens the main valve member away from its the main valve seat. The improvement comprises; the housing means has a thermostatically controlled means that is operatively associated with the lever and is adapted to engage and hold the lever in a position wherein the main valve member is in a closed condition against its the main valve seat when the thermostatically controlled means is in one operating condition thereof and the actuator means is in the on condition thereof.

  19. Operating experience with a 250 kW el molten carbonate fuel cell (MCFC) power plant

    NASA Astrophysics Data System (ADS)

    Bischoff, Manfred; Huppmann, Gerhard

    The MTU MCFC program is carried out by a European consortium comprising the German companies MTU Friedrichshafen GmbH, Ruhrgas AG and RWE Energie AG as well as the Danish company Energi E2 S/A. MTU acts as consortium leader. The company shares a license and technology exchange agreement with Fuel Cell Energy Inc., Danbury, CT, USA (formerly Energy Research Corp., ERC). The program was started in 1990 and covers a period of about 10 years. The highlights of this program to date are: Considerable improvements regarding component stability have been demonstrated on laboratory scale. Manufacturing technology has been developed to a point which enables the consortium to fabricate the porous components on a 250 cm 2 scale. Several large area stacks with 5000-7660 cm 2 cell area and a power range of 3-10 kW have been tested at the facilities in Munich (Germany) and Kyndby (Denmark). These stacks have been supplied by FCE. As far as the system design is concerned it was soon realized that conventional systems do not hold the promise for competitive power plants. A system analysis led to the conclusion that a new innovative design approach is required. As a result the "Hot Module" system was developed by the consortium. A Hot Module combines all the components of a MCFC system operating at the similar temperatures and pressures into a common thermally insulated vessel. In August 1997 the consortium started its first full size Hot Module MCFC test plant at the facilities of Ruhrgas AG in Dorsten, Germany. The stack was assembled in Munich using 292 cell packages purchased from FCE. The plant is based on the consortium's unique and proprietary "Hot Module" concept. It operates on pipeline natural gas and was grid connected on 16 August 1997. After a total of 1500 h of operation, the plant was intentionally shut down in a controlled manner in April 1998 for post-test analysis. The Hot Module system concept has demonstrated its functionality. The safety concept has been

  20. Acceleration tests: Degradation of anode-supported planar solid oxide fuel cells at elevated operating temperatures

    NASA Astrophysics Data System (ADS)

    Kim, Sun Jae; Choi, Moon-Bong; Park, Mansoo; Kim, Hyoungchul; Son, Ji-Won; Lee, Jong-Ho; Kim, Byung-Kook; Lee, Hae-Weon; Kim, Seung-Goo; Yoon, Kyung Joong

    2017-08-01

    As the solid oxide fuel cell (SOFC) technology matures, durability under real operating conditions is considered as one of the most critical issues for commercialization. The severe conditions encountered in practical operation include a large temperature gradient and generation of local hot spots within stacks. Herein, we report the degradation mechanisms of anode-supported planar SOFCs supplied by Posco Energy at elevated operating temperatures. A simple comparison of the voltage reduction rates at different operating temperatures does not appropriately represent the degree of degradation, because the rapid deterioration of the cell components at high temperatures is compensated for by the fast reaction and transport kinetics. A combination of impedance interpretation and post-mortem analysis reveals the major degradation processes that are distinctively accelerated by increasing temperature, including the chemical interaction between the cathode and electrolyte, the enlargement of the interfacial pores, the coarsening of the fine particles in the composite electrodes, the formation of interfacial cracks and Cr poisoning. Systematic analysis presented in this study provides guidelines for counteracting the unexpected temperature increase, and the database established under various extreme conditions would form the groundwork for achieving the lifetime goals of commercial SOFC systems.

  1. Ice formation in PEM fuel cells operated isothermally at sub-freezing temperatures

    SciTech Connect

    Mukundan, Rangachary; Luhan, Roger W; Davey, John R; Spendelow, Jacob S; Borup, Rodney L; Hussey, Daniel S; Jacobson, David L; Arif, Muhammad

    2009-01-01

    The effect of MEA and GDL structure and composition on the performance of single-PEM fuel cells operated isothermally at subfreezing temperatures is presented. The cell performance and durability are not only dependent on the MEA/GDL materials used but also on their interfaces. When a cell is operated isothermally at sub-freezing temperatures in constant current mode, the water formation due to the current density initially hydrates the membrane/ionomer and then forms ice in the catalyst layer/GDL. An increase in high frequency resistance was also observed in certain MEAs where there is a possibility of ice formation between the catalyst layer and GDL leading to a loss in contact area. The total water/ice holding capacity for any MEA was lower at lower temperatures and higher current densities. The durability of MEAs subjected to multiple isothermal starts was better for LANL prepared MEAs as compared to commercial MEAs, and cloth GDLs when compared to paper GDLs. The ice formation was monitored using high-resolution neutron radiography and was found to be concentrated near the cathode catalyst layer. However, there was significant ice formation in the GDLs especially at the higher temperature ({approx} -10 C) and lower current density (0.02 A/cm{sup 2}) operations. These results are consistent with the longer-term durability observations that show more severe degradation at the lower temperatures.

  2. Statistic analysis of operational influences on the cold start behaviour of PEM fuel cells

    NASA Astrophysics Data System (ADS)

    Oszcipok, M.; Riemann, D.; Kronenwett, U.; Kreideweis, M.; Zedda, M.

    For portable fuel cell systems a multitude of applications have been presented over the past few years. Most of these applications were developed for indoor use, and not optimised for outdoor conditions. The key problem concerning this case is the cold start ability of the polymer electrolyte membrane fuel cell (PEMFC). This topic was first investigated by the automotive industry, which has the same requirements for alternative traction systems as for conventional combustion engines. The technical challenge is the fact that produced water freezes to ice after shut-down of the PEMFC and during start-up when the temperature is below 0 °C. To investigate the basic cold start behaviour isothermal, potentiostatic single cell experiments were performed and the results are presented. The cold start behaviour is evaluated using the calculated cumulated charge transfer through the membrane which directly corresponds with the amount of produced water in the PEMFC. The charge transfer curves were mathematically fitted to obtain only three parameters describing the cold start-up with the cumulated charge transfer density and the results are analysed using the statistical software Cornerstone 4.0. The results of the statistic regression analyses are used to establish a statistic-based prediction model of the cold start behaviour which describes the behaviour of the current density during the experiment. The regression shows that the initial start current mainly depends on the membrane humidity and the operation voltage. After the membrane humidity has reached its maximum, the current density drops down to zero. The current decay also depends on the constant gas flows of the reactant gases. Ionic conductivity of the membrane and charge transfer resistance were investigated by a series of ac impedance spectra during potentiostatic operation of the single cell at freezing temperatures. Cyclic voltammetry and polarisation curves between cold start experiments show degradation

  3. The unitized regenerative fuel cell

    SciTech Connect

    1997-05-01

    Fuel cells can operate on hydrogen fuel and oxygen from air. If the fuel cell is designed to also operate in reverse as an electrolyzer, then electricity can be used to convert the water back into hydrogen and oxygen. This dual function system is known as a reversible or unitized regenerative fuel cell. This is an excellent energy source in situations where weight is a concern.

  4. Durability of Polymer Electrolyte Membrane Fuel Cells Operated at Subfreezing Temperatures

    SciTech Connect

    Macauley, Natalia; Lujan, Roger W.; Spernjak, Dusan; Hussey, Daniel S.; Jacobson, David L.; More, Karren; Borup, Rodney L.; Mukundan, Rangachary

    2016-09-15

    The structure, composition, and interfaces of membrane electrode assemblies (MEA) and gas-diffusion layers (GDLs) have a significant effect on the performance of single-proton-exchange-membrane (PEM) fuel cells operated isothermally at subfreezing temperatures. During isothermal constant-current operation at subfreezing temperatures, water forming at the cathode initially hydrates the membrane, then forms ice in the catalyst layer and/or GDL. This ice formation results in a gradual decay in voltage. High-frequency resistance initially decreases due to an increase in membrane water content and then increases over time as the contact resistance increases. The water/ice holding capacity of a fuel cell decreases with decreasing subfreezing temperature (-10°C vs. -20°C vs. -30°C) and increasing current density (0.02 A cm-2 vs. 0.04 A cm-2). Ice formation monitored using in-situ high-resolution neutron radiography indicated that the ice was concentrated near the cathode catalyst layer at low operating temperatures (≈-20°C) and high current densities (0.04 A cm-2). Significant ice formation was also observed in the GDLs at higher subfreezing temperatures (≈-10°C) and lower current densities (0.02 A cm-2). These results are in good agreement with the long-term durability observations that show more severe degradation at lower temperatures (-20°C and -30°C).

  5. Operational Concept Evaluation of Solid Oxide Fuel Cells for Space Vehicle Applications

    NASA Technical Reports Server (NTRS)

    Poast, Kenneth I.

    2011-01-01

    With the end of the Space Shuttle Program, NASA is evaluating many different technologies to support future missions. Green propellants, like liquid methane and liquid oxygen, have potential advantages for some applications. A Lander propelled with LOX/methane engines is one such application. When the total vehicle design and infrastructure are considered, the advantages of the integration of propulsion, heat rejection, life support and power generation become attractive for further evaluation. Scavenged residual propellants from the propulsion tanks could be used to generate needed electric power, heat and water with a Solid Oxide Fuel Cell(SOFC). In-Situ Resource Utilization(ISRU) technologies may also generate quantities of green propellants to refill these tanks and/or supply these fuel cells. Technology demonstration projects such as the Morpheus Lander are currently underway to evaluate the practicality of such designs and operational concepts. Tethered tests are currently in progress on this vertical test bed to evaluate the propulsion and avionics systems. Evaluation of the SOFC seeks to determine the feasibility of using these green propellants to supply power and identify the limits to the integration of this technology into a space vehicle prototype.

  6. Fuel cell

    SciTech Connect

    Struthers, R.C.

    1983-06-28

    An improved fuel cell comprising an anode section including an anode terminal, an anode fuel, and an anolyte electrolyte, a cathode section including a cathode terminal, an electron distributor and a catholyte electrolyte, an ion exchange section between the anode and cathode sections and including an ionolyte electrolyte, ion transfer membranes separating the ionolyte from the anolyte and the catholyte and an electric circuit connected with and between the terminals conducting free electrons from the anode section and delivering free electrons to the cathode section, said ionolyte receives ions of one polarity moving from the anolyte through the membrane related thereto preventing chemical equilibrium in the anode section and sustaining chemical reaction and the generating of free electrons therein, said ions received by the ionolyte from the anolyte release different ions from the ionolyte which move through the membrane between the ionolyte and catholyte and which add to the catholyte.

  7. Durability of Low Platinum Fuel Cells Operating at High Power Density

    SciTech Connect

    Polevaya, Olga; Blanchet, Scott; Ahluwalia, Rajesh; Borup, Rod; Mukundan, Rangachary

    2014-03-19

    Understanding and improving the durability of cost-competitive fuel cell stacks is imperative to successful deployment of the technology. Stacks will need to operate well beyond today’s state-of-the-art rated power density with very low platinum loading in order to achieve the cost targets set forth by DOE ($15/kW) and ultimately be competitive with incumbent technologies. An accelerated cost-reduction path presented by Nuvera focused on substantially increasing power density to address non-PGM material costs as well as platinum. The study developed a practical understanding of the degradation mechanisms impacting durability of fuel cells with low platinum loading (≤0.2mg/cm2) operating at high power density (≥1.0W/cm2) and worked out approaches for improving the durability of low-loaded, high-power stack designs. Of specific interest is the impact of combining low platinum loading with high power density operation, as this offers the best chance of achieving long-term cost targets. A design-of-experiments approach was utilized to reveal and quantify the sensitivity of durability-critical material properties to high current density at two levels of platinum loading (the more conventional 0.45 mgPt.cm–1 and the much lower 0.2 mgPt.cm–2) across several cell architectures. We studied the relevance of selected component accelerated stress tests (AST) to fuel cell operation in power producing mode. New stress tests (NST) were designed to investigate the sensitivity to the addition of electrical current on the ASTs, along with combined humidity and load cycles and, eventually, relate to the combined city/highway drive cycle. Changes in the cathode electrochemical surface area (ECSA) and average oxygen partial pressure on the catalyst layer with aging under AST and NST protocols were compared based on the number of completed cycles. Studies showed elevated sensitivity of Pt growth to the potential limits and the initial particle size distribution. The ECSA loss

  8. Use of silicone membranes to enhance gas transfer during microbial fuel cell operation on carbon monoxide.

    PubMed

    Hussain, A; Tartakovsky, B; Guiot, S R; Raghavan, V

    2011-12-01

    Electricity generation in a microbial fuel cell (MFC) using carbon monoxide (CO) or synthesis gas (syngas) as a carbon source has been demonstrated recently. A major challenge associated with CO or syngas utilization is the mass transfer limitation of these sparingly soluble gases in the aqueous phase. This study evaluated the applicability of a dense polymer silicone membrane and thin wall silicone tubing for CO mass transfer in MFCs. Replacing the sparger used in our previous study with the membrane systems for CO delivery resulted in improved MFC performance and CO transformation efficiency. A power output and CO transformation efficiency of up to 18 mW LR(-1) (normalized to anode compartment volume) and 98%, respectively, was obtained. The use of membrane systems offers the advantage of improved mass transfer and reduced reactor volume, thus increasing the volumetric power output of MFCs operating on a gaseous substrate such as CO.

  9. LIQUID HYDROCARBON FUEL CELL DEVELOPMENT.

    DTIC Science & Technology

    A compound anode consists of a reforming catalyst bed in direct contact with a palladium-silver fuel cell anode. The objective of this study was to...prove the feasibility of operating a compound anode fuel cell on a liquid hydrocarbon and to define the important parameters that influence cell...performance. Both reformer and fuel cell tests were conducted with various liquid hydrocarbon fuels. Included in this report is a description of the

  10. Biofuel cell operating on activated THP-1 cells: A fuel and substrate study.

    PubMed

    Javor, Kristina; Tisserant, Jean-Nicolas; Stemmer, Andreas

    2017-01-15

    It is known that electrochemical energy can be harvested from mammalian cells, more specifically from white blood cells (WBC). This study focuses on an improved biofuel cell operating on phorbol myristate acetate (PMA) activated THP-1 human monocytic cells. Electrochemical investigation showed strong evidence pointing towards hydrogen peroxide being the primary current source, confirming that the current originates from NADPH oxidase activity. Moreover, an adequate substrate for differentiation and activation of THP-1 cells was examined. ITO, gold, platinum and glass were tested and the amount of superoxide anion produced by NADPH oxidase was measured by spectrophotometry through WST-1 reduction at 450nm and used as an indicator of cellular activity and viability. These substrates were subsequently used in a conventional two-compartment biofuel cell where the power density output was recorded. The material showing the highest cell activity compared to the reference cell culture plate and the highest power output was ITO. Under our experimental conditions, a power density of 4.5μW/cm(2) was reached. To the best of our knowledge, this is a threefold higher power output than other leukocyte biofuel cells. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Optimizing operating conditions and electrochemical characterization of glucose-gluconate alkaline fuel cells

    NASA Astrophysics Data System (ADS)

    Pasta, M.; La Mantia, F.; Ruffo, R.; Peri, F.; Pina, C. Della; Mari, C. M.

    The direct oxidation of glucose to produce electrical energy has been widely investigated because of renewability, abundance, high energy density and easy handling of the carbohydrate. Most of the previous studies have been conducted in extreme conditions in order to achieve complete glucose oxidation to CO 2, neglecting the carbohydrate chemical instability that generally leads to useless by-products mixtures. The partial oxidation to gluconate, originally studied for implantable fuel cells, has the advantage of generating a commercially valuable chemical. In the present paper we optimized fuel composition and operating conditions in order to selectively oxidize glucose to gluconate, maximizing the power density output of a standard commercial platinum based anode material. A deep electrochemical characterization concerning reversible potential, cyclic voltammetry and overpotential measurements have been carried out at 25 °C in the D-(+)-glucose concentration range 1.0 × 10 -2 to 1.0 M. NMR and EIS investigation clarify the role of the buffer in enhancing the electrochemical performance.

  12. The Role of Fuel Cells in the Supply of Silent Power for Operations in Littoral Waters

    DTIC Science & Technology

    2004-04-01

    the last ten years, Siemens have developed a 34 kW PEM fuel cell for module for AIP (see figure 3) and a 300 kW assembly of these modules (see...process. This is a reversible poison for the platinum catalyst used in PEM fuel cells and therefore purification of the gas is required before it is...LOX tanks outside the pressure hull provides a greater degree of safety, although internal storage is practised, and models have demonstrated

  13. Study of the long-term operation of a vanadium/oxygen fuel cell

    NASA Astrophysics Data System (ADS)

    Noack, Jens; Cognard, Gwenn; Oral, Meryem; Küttinger, Michael; Roznyatovskaya, Nataliya; Pinkwart, Karsten; Tübke, Jens

    2016-09-01

    A vanadium/oxygen fuel cell (VOFC) with a geometrically active area of 51 cm2 and two membranes was discontinuously operated over a period of over 676 h with 47 successive tests at room temperature with a current density of 19.6 mA/cm2 in order to investigate signs of ageing. As well as measuring cell voltages, the test setup was also used to measure anode and redox potentials as well as cell and half-cell impedances. The performance data of the VOFC fluctuated widely over the course of the test period, due to different V2+ concentrations and instabilities of the starting solutions on the one hand and complex changes in cathode conditions on the other. The desired behaviour of the anode reactions was achieved primarily through improved methods for producing the V2+ solutions, and remained stable at the end of the experiments. The kinetics of the cathode reactions were temporarily increased by purging with 2 M H2SO4, however their performance decreased over time. The VOFC had symptoms of ageing by complex and overlaid changes in the cathode's triple phase boundary layer and in the special conditions between the two electrodes and membranes.

  14. Identifying the microbial communities and operational conditions for optimized wastewater treatment in microbial fuel cells.

    PubMed

    Ishii, Shun'ichi; Suzuki, Shino; Norden-Krichmar, Trina M; Wu, Angela; Yamanaka, Yuko; Nealson, Kenneth H; Bretschger, Orianna

    2013-12-01

    Microbial fuel cells (MFCs) are devices that exploit microorganisms as "biocatalysts" to recover energy from organic matter in the form of electricity. MFCs have been explored as possible energy neutral wastewater treatment systems; however, fundamental knowledge is still required about how MFC-associated microbial communities are affected by different operational conditions and can be optimized for accelerated wastewater treatment rates. In this study, we explored how electricity-generating microbial biofilms were established at MFC anodes and responded to three different operational conditions during wastewater treatment: 1) MFC operation using a 750 Ω external resistor (0.3 mA current production); 2) set-potential (SP) operation with the anode electrode potentiostatically controlled to +100 mV vs SHE (4.0 mA current production); and 3) open circuit (OC) operation (zero current generation). For all reactors, primary clarifier effluent collected from a municipal wastewater plant was used as the sole carbon and microbial source. Batch operation demonstrated nearly complete organic matter consumption after a residence time of 8-12 days for the MFC condition, 4-6 days for the SP condition, and 15-20 days for the OC condition. These results indicate that higher current generation accelerates organic matter degradation during MFC wastewater treatment. The microbial community analysis was conducted for the three reactors using 16S rRNA gene sequencing. Although the inoculated wastewater was dominated by members of Epsilonproteobacteria, Gammaproteobacteria, and Bacteroidetes species, the electricity-generating biofilms in MFC and SP reactors were dominated by Deltaproteobacteria and Bacteroidetes. Within Deltaproteobacteria, phylotypes classified to family Desulfobulbaceae and Geobacteraceae increased significantly under the SP condition with higher current generation; however those phylotypes were not found in the OC reactor. These analyses suggest that species

  15. PEM regenerative fuel cells

    NASA Technical Reports Server (NTRS)

    Swette, Larry L.; Laconti, Anthony B.; Mccatty, Stephen A.

    1993-01-01

    This paper will update the progress in developing electrocatalyst systems and electrode structures primarily for the positive electrode of single-unit solid polymer proton exchange membrane (PEM) regenerative fuel cells. The work was done with DuPont Nafion 117 in complete fuel cells (40 sq cm electrodes). The cells were operated alternately in fuel cell mode and electrolysis mode at 80 C. In fuel cell mode, humidified hydrogen and oxygen were supplied at 207 kPa (30 psi); in electrolysis mode, water was pumped over the positive electrode and the gases were evolved at ambient pressure. Cycling data will be presented for Pt-Ir catalysts and limited bifunctional data will be presented for Pt, Ir, Ru, Rh, and Na(x)Pt3O4 catalysts as well as for electrode structure variations.

  16. Effect of operating modes on simultaneous anaerobic sulfide and nitrate removal in microbial fuel cell.

    PubMed

    Cai, Jing; Zheng, Ping; Qaisar, Mahmood; Xing, Yajuan

    2014-05-01

    The effect of operating modes on the simultaneous sulfide and nitrate removal were studied in two-chamber microbial fuel cells (MFCs). The batch and continuous operating modes were compared and evaluated in terms of substrate removal and electricity generation. Upon gradual increase in the influent sulfide concentration from 60 to 1,020 S mg L(-1), and the hydraulic retention time decrease from 17.2 to 6 h, the MFC accomplished a good substrate removal efficiency whereby nitrogen and sulfate were the main end products. The removal efficiency of the MFC in the continuous mode was much higher than that in the batch mode, and its current densities in the continuous mode were more stable and higher than in the batch mode, which could be explained by the linear relationship between electrons released by the substrates and accepted on the electrodes. The electricity output in the continuous mode of the MFC was higher than that in the batch mode. MFC's operation in the continuous mode was a better strategy for the simultaneous treatment of sulfide and nitrate.

  17. Zirconia fuel cells and electrolyzers

    SciTech Connect

    Isaacs, H.S.

    1980-01-01

    A review of the historical development, operation, and problems of solid oxide electrolyte fuel cells and electrolyzers is given. The thermodynamic principles of operation are reviewed, and the overvoltage losses during operation of fuel cells and steam electrolyzers are discussed including physical factors and electrochemical factors. (WHK)

  18. An XAS experimental approach to study low Pt content electrocatalysts operating in PEM fuel cells.

    PubMed

    Principi, Emiliano; Witkowska, Agnieszka; Dsoke, Sonia; Marassi, Roberto; Di Cicco, Andrea

    2009-11-21

    We present an X-ray absorption spectroscopy (XAS) study of a low Pt content catalyst layer (Pt loading 0.1 mg cm(-2)) operating at the cathode of a proton exchange membrane fuel cell (PEMFC). This catalyst is based on the use of a mesoporous inorganic matrix as a support for the catalyst Pt nanoparticles. Due to the high Pt dilution, in situ measurements of its structural properties by XAS are challenging and suitable experimental strategies must be devised for this purpose. In particular, we show that accurate XAS in situ fluorescence measurements can be obtained using an optimized fuel cell, suitable protocols for alignment of a focused X-ray beam and an appropriate filter for the background signal of the other atomic species contained in the electrodes. Details, advantages and limitations of the XAS technique for in situ measurements are discussed. Analysis of the near-edge XAS and EXAFS (extended X-ray absorption fine structure) data, corroborated by a HRTEM (high-resolution transmission electron microscopy) study, shows that the Pt particles have a local structure compatible with that of bulk Pt (fcc) and coordination numbers match those expected for particles with typical sizes in the 1.5-2.0 nm range. Substantial changes in the oxidation state and in local atomic arrangement of the Pt particles are found for different applied potentials. The catalyst support, containing W atoms, exhibits a partial reduction upon PEMFC activation, thus mimicking the catalyst behavior. This indicates a possible role of the mesoporous matrix in favouring the oxygen reduction reaction (ORR) and stimulates further research on active catalyst supports.

  19. Impacts of operating conditions on the effects of chloride contamination on PEM fuel cell performance and durability

    NASA Astrophysics Data System (ADS)

    Li, Hui; Zhang, Shengsheng; Qian, Weimin; Yu, Yi; Yuan, Xiao-Zi; Wang, Haijiang; Jiang, Max; Wessel, Silvia; Cheng, Tommy T. H.

    2012-11-01

    Chloride contaminated fuel and/or air streams in an operating proton exchange membrane fuel cell can cause significant adverse effects on fuel cell performance and durability. This paper reports investigations of chloride contamination effects on PEM fuel cell performance and durability under a wide range of operating conditions, using various in-situ diagnostic measurements. Increases in current density and Cl- concentration as well as decreases in fuel cell RH were found to enlarge the severity of the chloride contamination effect. Temperature was also found to have a significant influence on the contamination effect. Electrochemical impedance spectroscopy was used as a diagnostic tool during the contamination tests to explore changes in cell component resistances. The results indicated that chloride contamination causes predominantly an increase in charge transfer resistance as well as an increase in mass transfer resistance. The membrane resistance was not found to be impacted by chloride contamination. As measured by cyclic voltammetry, the presence of chloride in the air stream significantly reduced the cathode electrochemical surface area, and this reduction is believed to be due to the adsorption of chloride on the Pt surface causing active site blockage and accelerated Pt dissolution and agglomeration via the formation of Pt-Cl complexes.

  20. Fuel Cell Handbook, Fifth Edition

    SciTech Connect

    Energy and Environmental Solutions

    2000-10-31

    Progress continues in fuel cell technology since the previous edition of the Fuel Cell Handbook was published in November 1998. Uppermost, polymer electrolyte fuel cells, molten carbonate fuel cells, and solid oxide fuel cells have been demonstrated at commercial size in power plants. The previously demonstrated phosphoric acid fuel cells have entered the marketplace with more than 220 power plants delivered. Highlighting this commercial entry, the phosphoric acid power plant fleet has demonstrated 95+% availability and several units have passed 40,000 hours of operation. One unit has operated over 49,000 hours. Early expectations of very low emissions and relatively high efficiencies have been met in power plants with each type of fuel cell. Fuel flexibility has been demonstrated using natural gas, propane, landfill gas, anaerobic digester gas, military logistic fuels, and coal gas, greatly expanding market opportunities. Transportation markets worldwide have shown remarkable interest in fuel cells; nearly every major vehicle manufacturer in the U.S., Europe, and the Far East is supporting development. This Handbook provides a foundation in fuel cells for persons wanting a better understanding of the technology, its benefits, and the systems issues that influence its application. Trends in technology are discussed, including next-generation concepts that promise ultrahigh efficiency and low cost, while providing exceptionally clean power plant systems. Section 1 summarizes fuel cell progress since the last edition and includes existing power plant nameplate data. Section 2 addresses the thermodynamics of fuel cells to provide an understanding of fuel cell operation at two levels (basic and advanced). Sections 3 through 8 describe the six major fuel cell types and their performance based on cell operating conditions. Alkaline and intermediate solid state fuel cells were added to this edition of the Handbook. New information indicates that manufacturers have stayed

  1. Influence of gadolinium doping on the structure and defects of ceria under fuel cell operating temperature

    SciTech Connect

    Acharya, S. A. Gaikwad, V. M.; Sathe, V.; Kulkarni, S. K.

    2014-03-17

    Correlation between atomic positional shift, oxygen vacancy defects, and oxide ion conductivity in doped ceria system has been established in the gadolinium doped ceria system from X-ray diffraction (XRD) and Raman spectroscopy study at operating temperature (300–600 °C) of Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC). High temperature XRD data are used to quantify atomic positional shift from mean position with temperature. The Raman spectroscopy study shows additional vibration modes related to ordering of defect spaces (Gd{sub Ce}{sup ′}−V{sub o}{sup ••}){sup *} and (2Gd{sub Ce}{sup ′}−V{sub o}{sup ••}){sup x} generated due to association of oxygen vacancies and reduced cerium or dopant cations site (Gd{sup 3+}), which disappear at 450 °C; indicating oxygen vacancies dissociation from the defect complex. The experimental evidences of cation-anion positional shifting and oxygen vacancies dissociation from defect complex in the IT-SOFC operating temperature are discussed to correlate with activation energy for ionic conductivity.

  2. Fuel cell technology program

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A fuel cell technology program was established to advance the state-of-the art of hydrogen oxygen fuel cells using low temperature, potassium hydroxide electrolyte technology as the base. Cell and component testing confirmed that low temperature, potassium hydroxide electrolyte technology is compatible with the requirements of the space shuttle Phase B contractors. Testing of the DM-1 powerplant demonstrated all of the important requirements of the shuttle except operating life. Testing also identified DM-1 powerplant life limiting mechanisms; hydrogen pump gear wear and pressurization of the cell stack over its design limits.

  3. Experimental analysis of spatio-temporal behavior of anodic dead-end mode operated polymer electrolyte fuel cell

    NASA Astrophysics Data System (ADS)

    Manokaran, A.; Pushpavanam, S.; Sridhar, P.; Pitchumani, S.

    During the anodic dead-end mode operation of fuel cells, the inert gases (nitrogen and water) present in the cathode side gas channel permeate to the anode side and accumulate in the anode gas channel. The inert gas accumulation in the anode decreases the fuel cell performance by impeding the access of hydrogen to the catalyst. The performance of fuel cell under potentiostatic dead-end mode operation is shown to have three distinct regions viz. time lag region, transient current region and a steady state current region. A current distribution measurement setup is used to capture the evolution of the current distribution as a function of time and space. Co- and counter-flow operations of dead-end mode confirm the propagation of inert gas from the dead-end of anode channel to the inlet of anode. Experiments with different oxidants, oxygen and air, under dead-end mode confirm that nitrogen which permeates from cathode to anode causes the performance drop of the fuel cell. For different starting current densities of 0.15 A cm -2, 0.3 A cm -2 and 0.6 A cm -2 the inert gas occupies 35%, 45% and 57%, respectively of anode channel volume at the end of 60 min of dead-end mode operation.

  4. Assessment of the performance of Ni-yttria-stabilized zirconia anodes in anode-supported Solid Oxide Fuel Cells operating on H 2-CO syngas fuels

    NASA Astrophysics Data System (ADS)

    Ye, Xiao-Feng; Wang, S. R.; Zhou, J.; Zeng, F. R.; Nie, H. W.; Wen, T. L.

    Anode-supported Solid Oxide Fuel Cells (SOFCs) with Ni-yttria-stabilized zirconia (YSZ) anode have been fabricated and studied using H 2-CO syngas fuels. Syngas fuels with different compositions of H 2-CO are supplied and the cell performance is measured at 750 °C. A high CO content has caused carbon deposition and crack formation in the Ni-YSZ anode after long-term operation, even though it is diluted with H 2O and N 2. However, it was found that a Cu-CeO 2 coating on Ni-YSZ can greatly improve the anode stability in syngas by facilitating the water gas shift reaction. The optimized single cell has run in sygas with a composition of 65%H 2-32%CO-3%H 2O for 1050 h without obvious degradation of its performance.

  5. Alkaline fuel cells applications

    NASA Astrophysics Data System (ADS)

    Kordesch, Karl; Hacker, Viktor; Gsellmann, Josef; Cifrain, Martin; Faleschini, Gottfried; Enzinger, Peter; Fankhauser, Robert; Ortner, Markus; Muhr, Michael; Aronson, Robert R.

    On the world-wide automobile market technical developments are increasingly determined by the dramatic restriction on emissions as well as the regimentation of fuel consumption by legislation. Therefore there is an increasing chance of a completely new technology breakthrough if it offers new opportunities, meeting the requirements of resource preservation and emission restrictions. Fuel cell technology offers the possibility to excel in today's motive power techniques in terms of environmental compatibility, consumer's profit, costs of maintenance and efficiency. The key question is economy. This will be decided by the costs of fuel cell systems if they are to be used as power generators for future electric vehicles. The alkaline hydrogen-air fuel cell system with circulating KOH electrolyte and low-cost catalysed carbon electrodes could be a promising alternative. Based on the experiences of Kordesch [K. Kordesch, Brennstoffbatterien, Springer, Wien, 1984, ISBN 3-387-81819-7; K. Kordesch, City car with H 2-air fuel cell and lead-battery, SAE Paper No. 719015, 6th IECEC, 1971], who operated a city car hybrid vehicle on public roads for 3 years in the early 1970s, improved air electrodes plus new variations of the bipolar stack assembly developed in Graz are investigated. Primary fuel choice will be a major issue until such time as cost-effective, on-board hydrogen storage is developed. Ammonia is an interesting option. The whole system, ammonia dissociator plus alkaline fuel cell (AFC), is characterised by a simple design and high efficiency.

  6. Fuel Cell Handbook, Fourth Edition

    SciTech Connect

    Stauffer, D.B; Hirschenhofer, J.H.; Klett, M.G.; Engleman, R.R.

    1998-11-01

    Robust progress has been made in fuel cell technology since the previous edition of the Fuel Cell Handbook was published in January 1994. This Handbook provides a foundation in fuel cells for persons wanting a better understanding of the technology, its benefits, and the systems issues that influence its application. Trends in technology are discussed, including next-generation concepts that promise ultra high efficiency and low cost, while providing exceptionally clean power plant systems. Section 1 summarizes fuel cell progress since the last edition and includes existing power plant nameplate data. Section 2 addresses the thermodynamics of fuel cells to provide an understanding of fuel cell operation at two levels (basic and advanced). Sections 3 through 6 describe the four major fuel cell types and their performance based on cell operating conditions. The section on polymer electrolyte membrane fuel cells has been added to reflect their emergence as a significant fuel cell technology. Phosphoric acid, molten carbonate, and solid oxide fuel cell technology description sections have been updated from the previous edition. New information indicates that manufacturers have stayed with proven cell designs, focusing instead on advancing the system surrounding the fuel cell to lower life cycle costs. Section 7, Fuel Cell Systems, has been significantly revised to characterize near-term and next-generation fuel cell power plant systems at a conceptual level of detail. Section 8 provides examples of practical fuel cell system calculations. A list of fuel cell URLs is included in the Appendix. A new index assists the reader in locating specific information quickly.

  7. Electrochemical characterizations of microtubular solid oxide fuel cells under a long-term testing at intermediate temperature operation

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Toshiaki; Galloway, Kevin V.; Yoon, Jieon; Sammes, Nigel M.

    2011-03-01

    We report the long-term stability of a microtubular solid oxide fuel cell (SOFC) operable at ∼500 °C. The SOFC consists of NiO-Gd doped ceria (GDC) as the anode as well as the tubular support, GDC as an electrolyte and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF)-GDC as the cathode. A single tubular cell with a diameter of approximately 1.8 mm and an effective electrode length of approximately 20 mm generated 150 mW cm-2 and 340 mW cm-2 at 500 °C and 550 °C, respectively, under the operation conditions of 0.7 V and humidified H2 fuel flow. The cell exhibited good stability with a degradation rate of 0.25%/100 h under operation conditions of 200 mA and 0.75 V.

  8. Hydrocarbon fuel effects in solid-oxide fuel cell operation: an experimental and modeling study of n-hexane pyrolysis.

    PubMed

    Randolph, Katie L; Dean, Anthony M

    2007-08-21

    Pyrolysis experiments of n-hexane were performed and the product distribution and fuel consumption were measured as a function of temperature. The experimental temperatures ranged from 550-675 degrees C, with a pressure of approximately 1 atm, and residence times of approximately 5 s. N-Hexane was used as a model compound to represent the linear alkanes that might be found in practical hydrocarbon fuels. Under these conditions, high fuel conversion was observed at the higher temperatures and a wide range of products were formed. The experimental observations were compared to predictions from a plug-flow model using a reaction mechanism consisting of 205 species and 1403 reactions. The hydrogen abstraction and isomerization rate coefficients in this model were based on CBS-QB3 calculations. The only model modification was adjustment of the A-factor of the initiation rates to match conversion at one temperature. This model was able to successfully predict the observed trends in both product selectivities as well as fuel conversion over the temperature range. The mechanism was also used to capture the trends previously observed in n-butane pyrolysis under similar experimental conditions. Significant differences in the sensitivity coefficients for the hexane and butane systems are discussed in terms of the competition between beta-scission and isomerization of the initial radicals formed. The kinetic model predicts that n-hexane will be completely converted within 0.1 s in the higher temperature environment ( approximately 800 degrees C) of the anode channel of a solid-oxide fuel cell (SOFC). This result clearly illustrates the need to explicitly account for gas-phase reactions in SOFC models for those cases where hydrocarbons, especially those larger than methane, are fed directly to an SOFC.

  9. Water outlet control mechanism for fuel cell system operation in variable gravity environments

    NASA Technical Reports Server (NTRS)

    Vasquez, Arturo (Inventor); McCurdy, Kerri L. (Inventor); Bradley, Karla F. (Inventor)

    2007-01-01

    A self-regulated water separator provides centrifugal separation of fuel cell product water from oxidant gas. The system uses the flow energy of the fuel cell's two-phase water and oxidant flow stream and a regulated ejector or other reactant circulation pump providing the two-phase fluid flow. The system further uses a means of controlling the water outlet flow rate away from the water separator that uses both the ejector's or reactant pump's supply pressure and a compressibility sensor to provide overall control of separated water flow either back to the separator or away from the separator.

  10. Fuel economy of hybrid fuel cell vehicles.

    SciTech Connect

    Ahluwalia, R.; Wang, X.; Rousseau, A.; Nuclear Engineering Division

    2004-01-01

    The potential improvement in fuel economy of a mid-size fuel-cell vehicle by combining it with an energy storage system has been assessed. An energy management strategy is developed and used to operate the direct hydrogen, pressurized fuel-cell system in a load-following mode and the energy storage system in a charge-sustaining mode. The strategy places highest priority on maintaining the energy storage system in a state where it can supply unanticipated boost power when the fuel-cell system alone cannot meet the power demand. It is found that downsizing a fuel-cell system decreases its efficiency on a drive cycle which is compensated by partial regenerative capture of braking energy. On a highway cycle with limited braking energy the increase in fuel economy with hybridization is small but on the stop-and-go urban cycle the fuel economy can improve by 27%. On the combined highway and urban drive cycles the fuel economy of the fuel-cell vehicle is estimated to increase by up to 15% by hybridizing it with an energy storage system.

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

    NASA Technical Reports Server (NTRS)

    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.

  12. Fuel utilization and fuel sensitivity of solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Huang, Kevin

    2011-03-01

    Fuel utilization and fuel sensitivity are two important process variables widely used in operation of SOFC cells, stacks, and generators. To illustrate the technical values, the definitions of these two variables as well as practical examples are particularly given in this paper. It is explicitly shown that the oxygen-leakage has a substantial effect on the actual fuel utilization, fuel sensitivity and V-I characteristics. An underestimation of the leakage flux could potentially results in overly consuming fuel and oxidizing Ni-based anode. A fuel sensitivity model is also proposed to help extract the leakage flux information from a fuel sensitivity curve. Finally, the "bending-over" phenomenon observed in the low-current range of a V-I curve measured at constant fuel-utilization is quantitatively coupled with leakage flux.

  13. Dual membrane hollow fiber fuel cell and method of operating same

    NASA Technical Reports Server (NTRS)

    Ingham, J. D.; Lawson, D. D. (Inventor)

    1978-01-01

    A gaseous fuel cell is described which includes a pair of electrodes formed by open-ended, ion-exchange hollow fibers, each having a layer of metal catalyst deposited on the inner surface and large surface area current collectors such as braided metal mesh in contact with the metal catalyst layer. A fuel cell results when the electrodes are immersed in electrolytes and electrically connected. As hydrogen and oxygen flow through the bore of the fibers, oxidation and reduction reactions develop an electrical potential. Since the hollow fiber configuration provides large electrode area per unit volume and intimate contact between fuel and oxidizer at the interface, and due to the low internal resistance of the electrolyte, high power densities can be obtained.

  14. Construction and operation of microbial fuel cell with Chlorella vulgaris biocathode for electricity generation.

    PubMed

    Wu, Xia-yuan; Song, Tian-shun; Zhu, Xu-jun; Wei, Ping; Zhou, Charles C

    2013-12-01

    In this study, a modified microbial fuel cell (MFC) with a tubular photobioreactor (PHB) configuration as a cathode compartment was constructed by introducing Chlorella vulgaris to the cathode chamber used to generate oxygen in situ. Two types of cathode materials and light/dark cycles were used to test the effect on MFC with algae biocathode. Results showed that the use of algae is an effective approach because these organisms can act as efficient in situ oxygenators, thereby facilitating the cathodic reaction. Dissolved oxygen and voltage output displayed a clear light positive response and were drastically enhanced compared with the abiotic cathode. In particular, carbon paper-coated Pt used as a cathode electrode increased voltage output at a higher extent than carbon felt used as an electrode. The maximum power density of 24.4 mW/m(2) was obtained from the MFC with algae biocathode which utilized the carbon paper-coated Pt as the cathode electrode under intermittent illumination. This density was 2.8 times higher than that of the abiotic cathode. Continuous illumination shortened the algal lifetime. These results demonstrated that intermittent illumination and cathode material-coated catalyst are beneficial to a more efficient and prolonged operation of MFC with C. vulgaris biocathode.

  15. Construction and operation of microbial fuel cell with Chlorella vulgaris biocathode for electricity generation.

    PubMed

    Wu, Xia-yuan; Song, Tian-shun; Zhu, Xu-jun; Wei, Ping; Zhou, Charles C

    2013-12-01

    In this study, a modified microbial fuel cell (MFC) with a tubular photobioreactor (PHB) configuration as a cathode compartment was constructed by introducing Chlorella vulgaris to the cathode chamber used to generate oxygen in situ. Two types of cathode materials and light/dark cycles were used to test the effect on MFC with algae biocathode. Results showed that the use of algae is an effective approach because these organisms can act as efficient in situ oxygenators, thereby facilitating the cathodic reaction. Dissolved oxygen and voltage output displayed a clear light positive response and were drastically enhanced compared with the abiotic cathode. In particular, carbon paper-coated Pt used as a cathode electrode increased voltage output at a higher extent than carbon felt used as an electrode. The maximum power density of 24.4 mW/m2 was obtained from the MFC with algae biocathode which utilized the carbon paper-coated Pt as the cathode electrode under intermittent illumination. This density was 2.8 times higher than that of the abiotic cathode. Continuous illumination shortened the algal lifetime. These results demonstrated that intermittent illumination and cathode material-coated catalyst are beneficial to a more efficient and prolonged operation of MFC with C. vulgaris biocathode.

  16. Electricity generation by Pyrococcus furiosus in microbial fuel cells operated at 90 °C.

    PubMed

    Sekar, Narendran; Wu, Chang-Hao; Adams, Michael W W; Ramasamy, Ramaraja P

    2017-02-20

    Hyperthermophiles are microorganisms that thrive in extremely hot environments with temperatures near and even above 100 (°) C. They are the most deeply rooted microorganisms on phylogenetic trees suggesting they may have evolved to survive in the early hostile earth. The simple respiratory systems of some of these hyperthermophiles made them potential candidates to develop microbial fuel cells (MFC) that can generate power at temperatures approaching the boiling point. We explored extracellular electron transfer ability of a hyperthermophilic archaeon Pyrococcus furiosus (Pf) by studying its ability to generate electricity in a two-chamber MFC. Pf growing in defined medium functioned as an anolyte in a MFC operated at 90 (°) C, generating a maximum current density of 2 A m(-2) and a peak power density of 225 mW m(-2) without the addition of any external redox mediator. Electron microscopy and electrochemical impedance spectroscopy of the anode with the attached Pf biofilm demonstrated bio-electrochemical behavior that led to electricity generation in MFC via direct electron transfer. This proof of concept study reveals for the first time that a hyperthermophile such as Pf can generate electricity in MFC at extreme temperatures. This article is protected by copyright. All rights reserved.

  17. Characterization of wastewater treatment by two microbial fuel cells in continuous flow operation.

    PubMed

    Kubota, Keiichi; Watanabe, Tomohide; Yamaguchi, Takashi; Syutsubo, Kazuaki

    2016-01-01

    A two serially connected single-chamber microbial fuel cell (MFC) was applied to the treatment of diluted molasses wastewater in a continuous operation mode. In addition, the effect of series and parallel connection between the anodes and the cathode on power generation was investigated experimentally. The two serially connected MFC process achieved 79.8% of chemical oxygen demand removal and 11.6% of Coulombic efficiency when the hydraulic retention time of the whole process was 26 h. The power densities were 0.54, 0.34 and 0.40 W m(-3) when electrodes were in individual connection, serial connection and parallel connection modes, respectively. A high open circuit voltage was obtained in the serial connection. Power density decreased at low organic loading rates (OLR) due to the shortage of organic matter. Power generation efficiency tended to decrease as a result of enhancement of methane fermentation at high OLRs. Therefore, high power density and efficiency can be achieved by using a suitable OLR range.

  18. Enhanced Performance of non-PGM Catalysts in Air Operated PEM-Fuel Cells

    SciTech Connect

    Barkholtz, Heather M.; Chong, Lina; Kaiser, Zachary Brian; Xu, Tao; Liu, Di-Jia

    2016-10-13

    Here a non-platinum group metal (non-PGM) oxygen reduction catalyst was prepared from “support-free” zeolitic imidazolate framework (ZIF) precursor and tested in the proton exchange membrane fuel cell with air as the cathode feed. The iron nitrogen and carbon composite (FeeNeC) based catalyst has high specific surface area decorated uniformly with active sites, which redefines the triple phase boundary (TPB) and requires re-optimization of the cathodic membrane electrode fabrication to ensure efficient mass and charge transports to the catalyst surface. This study reports an effort in optimizing catalytic ink formulation for the membrane electrode preparation and its impact to the fuel cell performance under air. Through optimization, the fuel cell areal current density as high as 115.2 mA/cm2 at 0.8 V or 147.6 mA/cm2 at 0.8 ViR-free has been achieved under one bar air. We also investigated impacts on fuel cell internal impedance and the water formation.

  19. Enhanced Performance of non-PGM Catalysts in Air Operated PEM-Fuel Cells

    SciTech Connect

    Barkholtz, Heather M.; Chong, Lina; Kaiser, Zachary Brian; Xu, Tao; Liu, Di-Jia

    2016-10-13

    Here a non-platinum group metal (non-PGM) oxygen reduction catalyst was prepared from “support-free” zeolitic imidazolate framework (ZIF) precursor and tested in the proton exchange membrane fuel cell with air as the cathode feed. The iron nitrogen and carbon composite (FeeNeC) based catalyst has high specific surface area decorated uniformly with active sites, which redefines the triple phase boundary (TPB) and requires re-optimization of the cathodic membrane electrode fabrication to ensure efficient mass and charge transports to the catalyst surface. This study reports an effort in optimizing catalytic ink formulation for the membrane electrode preparation and its impact to the fuel cell performance under air. Through optimization, the fuel cell areal current density as high as 115.2 mA/cm2 at 0.8 V or 147.6 mA/cm2 at 0.8 ViR-free has been achieved under one bar air. We also investigated impacts on fuel cell internal impedance and the water formation.

  20. TECHNICAL ASSESSMENT OF FUEL CELL OPERATION ON LANDFILL GAS AT THE GROTON, CT, LANDFILL

    EPA Science Inventory

    The paper summarizes the results from a seminal assessment conducted on a fuel cell technology which generates electrical power from waste landfill gas. This assessment/ demonstration was the second such project conducted by the EPA, the first being conducted at the Penrose Power...

  1. TECHNICAL ASSESSMENT OF FUEL CELL OPERATION ON LANDFILL GAS AT THE GROTON, CT, LANDFILL

    EPA Science Inventory

    The paper summarizes the results from a seminal assessment conducted on a fuel cell technology which generates electrical power from waste landfill gas. This assessment/ demonstration was the second such project conducted by the EPA, the first being conducted at the Penrose Power...

  2. ARPA advanced fuel cell development

    SciTech Connect

    Dubois, L.H.

    1995-08-01

    Fuel cell technology is currently being developed at the Advanced Research Projects Agency (ARPA) for several Department of Defense applications where its inherent advantages such as environmental compatibility, high efficiency, and low noise and vibration are overwhelmingly important. These applications range from man-portable power systems of only a few watts output (e.g., for microclimate cooling and as direct battery replacements) to multimegawatt fixed base systems. The ultimate goal of the ARPA program is to develop an efficient, low-temperature fuel cell power system that operates directly on a military logistics fuel (e.g., DF-2 or JP-8). The absence of a fuel reformer will reduce the size, weight, cost, and complexity of such a unit as well as increase its reliability. In order to reach this goal, ARPA is taking a two-fold, intermediate time-frame approach to: (1) develop a viable, low-temperature proton exchange membrane (PEM) fuel cell that operates directly on a simple hydrocarbon fuel (e.g., methanol or trimethoxymethane) and (2) demonstrate a thermally integrated fuel processor/fuel cell power system operating on a military logistics fuel. This latter program involves solid oxide (SOFC), molten carbonate (MCFC), and phosphoric acid (PAFC) fuel cell technologies and concentrates on the development of efficient fuel processors, impurity scrubbers, and systems integration. A complementary program to develop high performance, light weight H{sub 2}/air PEM and SOFC fuel cell stacks is also underway. Several recent successes of these programs will be highlighted.

  3. A small mono-polar direct methanol fuel cell stack with passive operation

    NASA Astrophysics Data System (ADS)

    Chan, Y. H.; Zhao, T. S.; Chen, R.; Xu, C.

    A passive direct methanol fuel cell (DMFC) stack that consists of six unit cells was designed, fabricated, and tested. The stack was tested with different methanol concentrations under ambient conditions. It was found that the stack performance increased when the methanol concentration inside the fuel tank was increased from 2.0 to 6.0 M. The improved performance is primarily due to the increased cell temperature as a result of the exothermic reaction between the permeated methanol and oxygen on the cathode. Moreover, the increased cell temperature enhanced the water evaporation rate on the air-breathing cathode, which significantly reduced water flooding on the cathode and further improved the stack performance. This passive DMFC stack, providing 350 mW at 1.8 V, was successfully applied to power a seagull display kit. The seagull display kit can continuously run for about 4 h on a single charge of 25 cm 3 4.0-M methanol solution.

  4. CLIMATE CHANGE FUEL CELL PROGRAM

    SciTech Connect

    Steven A. Gabrielle

    2004-12-03

    This report discusses the first year of operation of a fuel cell power plant located at the Sheraton Edison Hotel, Edison, New Jersey. PPL EnergyPlus, LLC installed the plant under a contract with the Starwood Hotels & Resorts Worldwide, Inc. A DFC{reg_sign}300 fuel cell, manufactured by FuelCell Energy, Inc. of Danbury, CT was selected for the project. The fuel cell successfully operated from June 2003 to May 2004. This report discusses the performance of the plant during this period.

  5. Performance evaluation of a liquid tin anode solid oxide fuel cell operating under hydrogen, argon and coal

    NASA Astrophysics Data System (ADS)

    Khurana, Sanchit; LaBarbera, Mark; Fedkin, Mark V.; Lvov, Serguei N.; Abernathy, Harry; Gerdes, Kirk

    2015-01-01

    A liquid tin anode solid oxide fuel cell is constructed and investigated under different operating conditions. Electrochemical Impedance Spectroscopy (EIS) is used to reflect the effect of fuel feed as the EIS spectra changes significantly on switching the fuel from argon to hydrogen. A cathode symmetric cell is used to separate the impedance from the two electrodes, and the results indicate that a major contribution to the charge-transfer and mass-transfer impedance arises from the anode. The OCP of 0.841 V for the cell operating under argon as a metal-air battery indicates the formation of a SnO2 layer at the electrolyte/anode interface. The increase in the OCP to 1.1 V for the hydrogen fueled cell shows that H2 reduces the SnO2 film effectively. The effective diffusion coefficients are calculated using the Warburg element in the equivalent circuit model for the experimental EIS data, and the values of 1.9 10-3 cm2 s-1 at 700 °C, 2.3 10-3 cm2 s-1 at 800 °C and 3.5 10-3 cm2 s-1 at 900 °C indicate the system was influenced by diffusion of hydrogen in the system. Further, the performance degradation over time is attributed to the irreversible conversion of Sn to SnO2 resulting from galvanic polarization.

  6. Comprehensive characterization and understanding of micro-fuel cells operating at high methanol concentrations.

    PubMed

    Gago, Aldo S; Esquivel, Juan-Pablo; Sabaté, Neus; Santander, Joaquín; Alonso-Vante, Nicolas

    2015-01-01

    We report on the analysis of the performance of each electrode of an air-breathing passive micro-direct methanol fuel cell (µDMFC) during polarization, stabilization and discharge, with CH3OH (2-20 M). A reference electrode with a microcapillary was used for separately measuring the anode the cathode potential. Information about the open circuit potential (OCP), the voltage and the mass transport related phenomena are available. Using 2 M CH3OH, the anode showed mass transport problems. With 4 and 6 M CH3OH both electrodes experience this situation, whereas with 10 and 20 M CH3OH the issue is attributed to the cathode. The stabilization and fuel consumption time depends mainly on the cathode performance, which is very sensitive to fuel crossover. The exposure to 20 M CH3OH produced a loss in performance of more than 75% of the highest power density (16.3 mW·cm(-2)).

  7. In situ PEM fuel cell water measurements

    SciTech Connect

    Borup, Rodney L; Mukundan, Rangachary; Davey, John R; Spendalow, Jacob S

    2008-01-01

    Efficient PEM fuel cell performance requires effective water management. The materials used, their durability, and the operating conditions under which fuel cells run, make efficient water management within a practical fuel cell system a primary challenge in developing commercially viable systems. We present experimental measurements of water content within operating fuel cells. in response to operational conditions, including transients and freezing conditions. To help understand the effect of components and operations, we examine water transport in operating fuel cells, measure the fuel cell water in situ and model the water transport within the fuel cell. High Frequency Resistance (HFR), AC Impedance and Neutron imaging (using NIST's facilities) were used to measure water content in operating fuel cells with various conditions, including current density, relative humidity, inlet flows, flow orientation and variable GDL properties. Ice formation in freezing cells was also monitored both during operation and shut-down conditions.

  8. Coke-free direct formic acid solid oxide fuel cells operating at intermediate temperatures

    NASA Astrophysics Data System (ADS)

    Chen, Yubo; Su, Chao; Zheng, Tao; Shao, Zongping

    2012-12-01

    Formic acid is investigated as a fuel for Solid Oxide Fuel Cells (SOFCs) for the first time. Thermodynamic calculations demonstrate that carbon deposition is avoidable above 600 °C. The carbon deposition properties are also investigated experimentally by first treating a nickel plus yttria-stabilized zirconia (Ni-YSZ) anode material in particle form under a formic acid-containing atmosphere for a limited time at 500-800 °C and then analyzing the particles by O2-TPO. This analysis confirms that carbon deposition on Ni-YSZ is weak above 600 °C. We further treat half-cells composed of YSZ electrolyte and Ni-YSZ anode under formic acid-containing atmosphere at 600, 700 and 800 °C; the anodes maintain their original geometric shape and microstructure and show no obvious weight gain. It suggests that formic acid can be directly fed into SOFCs constructed with conventional nickel-based cermet anodes. I-V tests show that the cell delivers a promising peak power density of 571 mW cm-2 at 800 °C. In addition, the cells also show good performance stability. The results indicate that formic acid is highly promising as a direct fuel for SOFCs without the need for cell material modifications.

  9. Fuel cell technology program

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A program to advance the technology for a cost-effective hydrogen/oxygen fuel cell system for future manned spacecraft is discussed. The evaluation of base line design concepts and the development of product improvements in the areas of life, power, specific weight and volume, versatility of operation, field maintenance and thermal control were conducted from the material and component level through the fabrication and test of an engineering model of the fuel cell system. The program was to be accomplished in a 13 month period.

  10. Fuel cells seminar

    SciTech Connect

    1996-12-01

    This year`s meeting highlights the fact that fuel cells for both stationary and transportation applications have reached the dawn of commercialization. Sales of stationary fuel cells have grown steadily over the past 2 years. Phosphoric acid fuel cell buses have been demonstrated in urban areas. Proton-exchange membrane fuel cells are on the verge of revolutionizing the transportation industry. These activities and many more are discussed during this seminar, which provides a forum for people from the international fuel cell community engaged in a wide spectrum of fuel cell activities. Discussions addressing R&D of fuel cell technologies, manufacturing and marketing of fuel cells, and experiences of fuel cell users took place through oral and poster presentations. For the first time, the seminar included commercial exhibits, further evidence that commercial fuel cell technology has arrived. A total of 205 papers is included in this volume.

  11. Study on proton-conducting solid oxide fuel cells with a conventional nickel cermet anode operating on dimethyl ether

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Guo, Youmin; Wang, Wei; Su, Chao; Ran, Ran; Wang, Huanting; Shao, Zongping

    This study investigates dimethyl ether (DME) as a potential fuel for proton-conducting SOFCs with a conventional nickel cermet anode and a BaZr 0.4Ce 0.4Y 0.2O 3-δ (BZCY4) electrolyte. A catalytic test demonstrates that the sintered Ni + BZCY4 anode has an acceptable catalytic activity for the decomposition and steam reforming of DME with CO, CH 4 and CO 2 as the only gaseous carbon-containing products. An O 2-TPO analysis demonstrates the presence of a large amount of coke formation over the anode catalyst when operating on pure DME, which is effectively suppressed by introducing steam into the fuel gas. The selectivity towards CH 4 is also obviously reduced. Peak power densities of 252, 280 and 374 mW cm -2 are achieved for the cells operating on pure DME, a DME + H 2O gas mixture (1:3) and hydrogen at 700 °C, respectively. After the test, the cell operating on pure DME is seriously cracked whereas the cell operating on DME + H 2O maintains its original integrity. A lower power output is obtained for the cell operating on DME + H 2O than on H 2 at low temperature, which is mainly due to the increased electrode polarization resistance. The selection of a better proton-conducting phase in the anode is critical to further increase the cell power output.

  12. A simple, analytic model of polymer electrolyte membrane fuel cell anode recirculation at operating power including nitrogen crossover

    NASA Astrophysics Data System (ADS)

    Promislow, Keith; St-Pierre, Jean; Wetton, Brian

    A simple, analytic model is presented that describes the steady state profile of anode nitrogen concentration in a polymer electrolyte membrane fuel cell operated with anode recirculation. The model is appropriate for fuel cells with straight gas channels and includes the effect of nitrogen crossover from cathode to anode through the membrane. The key analytic simplification in the model is that this crossover rate, when scaled to the gas flows in the channels, is small. This is a good approximation when the device is used at operating power levels. The model shows that the characteristic times for the anode nitrogen profiles to reach steady state are of the order of minutes and that the dilution effect of anode nitrogen is severe for pure recirculation. The model shows additionally that a small anode outlet bleed can significantly reduce the nitrogen dilution effect. Within the framework of the model, the energy efficiency of pure recirculation can be compared to hydrogen venting or partial anode bleeding. An optimal bleed rate is identified. The model and optimization analysis can be adapted to other fuel cell designs and operating conditions. Along with operating conditions, only two key parameters are needed: a nitrogen crossover coefficient and the marginal efficiency loss to compressors for increased anode stoichiometric gas flow.

  13. Method to improve reliability of a fuel cell system using low performance cell detection at low power operation

    DOEpatents

    Choi, Tayoung; Ganapathy, Sriram; Jung, Jaehak; Savage, David R.; Lakshmanan, Balasubramanian; Vecasey, Pamela M.

    2013-04-16

    A system and method for detecting a low performing cell in a fuel cell stack using measured cell voltages. The method includes determining that the fuel cell stack is running, the stack coolant temperature is above a certain temperature and the stack current density is within a relatively low power range. The method further includes calculating the average cell voltage, and determining whether the difference between the average cell voltage and the minimum cell voltage is greater than a predetermined threshold. If the difference between the average cell voltage and the minimum cell voltage is greater than the predetermined threshold and the minimum cell voltage is less than another predetermined threshold, then the method increments a low performing cell timer. A ratio of the low performing cell timer and a system run timer is calculated to identify a low performing cell.

  14. Enhanced Performance of non-PGM Catalysts in Air Operated PEM-Fuel Cells

    DOE PAGES

    Barkholtz, Heather M.; Chong, Lina; Kaiser, Zachary Brian; ...

    2016-10-13

    Here a non-platinum group metal (non-PGM) oxygen reduction catalyst was prepared from “support-free” zeolitic imidazolate framework (ZIF) precursor and tested in the proton exchange membrane fuel cell with air as the cathode feed. The iron nitrogen and carbon composite (FeeNeC) based catalyst has high specific surface area decorated uniformly with active sites, which redefines the triple phase boundary (TPB) and requires re-optimization of the cathodic membrane electrode fabrication to ensure efficient mass and charge transports to the catalyst surface. This study reports an effort in optimizing catalytic ink formulation for the membrane electrode preparation and its impact to the fuelmore » cell performance under air. Through optimization, the fuel cell areal current density as high as 115.2 mA/cm2 at 0.8 V or 147.6 mA/cm2 at 0.8 ViR-free has been achieved under one bar air. We also investigated impacts on fuel cell internal impedance and the water formation.« less

  15. Regenerative Fuel Cell Test Rig Completed and Operational at Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Bents, David J.

    2004-01-01

    The NASA Glenn Research Center has completed construction of its first closed-cycle hydrogen-oxygen regenerative fuel cell (RFC). The RFC is an electrochemical system that collects and stores solar energy during the day then releases that energy at night, thus making the Sun's energy available all 24 hours. It consists of a dedicated hydrogen-oxygen fuel cell stack and an electrolyzer stack, the interconnecting plumbing and valves, cooling pumps, water transfer pumps, gas recirculation pumps, phase separators, storage tanks for oxygen (O2) and hydrogen (H2), heat exchangers, isolation valves, pressure regulators, nitrogen purge provisions, instrumentation, and other components. It includes all the equipment required to (1) absorb electrical power from an outside source and store it as pressurized hydrogen and oxygen and (2) make electrical power from the stored gases, saving the product water for reuse during the next cycle.

  16. Startup, testing, and operation of the Santa Clara 2MW direct carbonate fuel cell demonstration plant

    SciTech Connect

    Skok, A.J.; Leo, A.J.; O`Shea, T.P.

    1996-12-31

    The Santa Clara Demonstration Project (SCDP) is a collaboration between several utility organizations, Fuel Cell Engineering Corporation (FCE), and the U.S. Dept. Of Energy aimed at the demonstration of Energy Research Corporation`s (ERC) direct carbonate fuel cell (DFC) technology. ERC has been pursuing the development of the DFC for commercialization near the end of this decade, and this project is an integral part of the ERC commercialization effort. The objective of the Santa Clara Demonstration Project is to provide the first full, commercial scale demonstration of this technology. The approach ERC has taken in the commercialization of the DFC is described in detail elsewhere. An aggressive core technology development program is in place which is focused by ongoing interaction with customers and vendors to optimize the design of the commercial power plant. ERC has selected a 2.85 MW power plant unit for initial market entry. Two ERC subsidiaries are supporting the commercialization effort: the Fuel Cell Manufacturing Corporation (FCMC) and the Fuel Cell Engineering Corporation (FCE). FCMC manufactures carbonate stacks and multi-stack modules, currently from its production facility in Torrington, CT. FCE is responsible for power plant design, integration of all subsystems, sales/marketing, and client services. FCE is serving as the prime contractor for the design, construction, and testing of the SCDP Plant. FCMC has manufactured the multi-stack submodules used in the DC power section of the plant. Fluor Daniel Inc. (FDI) served as the architect-engineer subcontractor for the design and construction of the plant and provided support to the design of the multi-stack submodules. FDI is also assisting the ERC companies in commercial power plant design.

  17. Chemically regenerable redox fuel cell and method of operating the same

    SciTech Connect

    Kummer, J.T.; Oei, D.G.

    1983-10-04

    A chemically regenerable redox fuel cell is disclosed. This fuel cell is one in which the oxidant is oxygen and the fuel is hydrogen. A catholyte solution is used. The catholyte solution is one which is reoxidized from a reduced state to an oxidized state by direct exposure of the catholyte solution to oxygen. An anolyte solution is also used. This anolyte solution is one which is reduced from an oxidized state to a reduced state by direct exposure of the catholyte solution to hydrogen. Structure is provided for containing in separate containers the catholyte solution and the anolyte solution, and for providing oxygen to the catholyte solution and hydrogen to the anolyte solution. A suitable cationic exchange membrane is housed in a housing and provided with volumes on opposite sides of the membrane for the catholyte solution and anolyte solution so that the necessary exchanges may take place to form the redox cell. All necessary plumbing and electrical systems are provided to supply the catholyte and anolyte solutions to the cationic exchange membrane and to obtain from the exchange which takes place at the membrane the electrical potential generated.

  18. Chemically regenerable redox fuel cell and method of operating the same

    SciTech Connect

    Kummer, J.T.; Oei, D.G.

    1983-08-02

    A chemically regenerable redox fuel cell is disclosed. This fuel cell is one in which the oxidant is oxygen and the fuel is hydrogen. A catholyte solution is used. The catholyte solution is one which reoxidized from a reduced state to an oxidized state by direct exposure of the catholyte solution oxygen. An anolyte solution is also used. This anolyte solution is one which is reduced from an oxidized state to a reduced state by direct exposure of the catholyte solution to hydrogen. Structure is provided for containing in separate containers the catholyte solution and the anolyte solution, for providing oxygen to the catholyte solution and hydrogen to the anolyte solution. A suitable cationic exchange membrane is housed in a housing and provided with volumes on opposite sides of the membrane for the catholyte solution and anolyte solution so that the necessary exchanges may take place to form the redox cell. All necessary plumbing and electrical systems are provided to supply catholyte and anolyte solutions to the cationic exchange membrane and to obtain from the exchange which takes place at the membrane the electrical potential generated.

  19. Fuel cell status, 1994

    NASA Astrophysics Data System (ADS)

    Hirschenhofer, John H.

    1994-11-01

    Fuel cells are increasingly being used for commercial purposes in various countries worldwide because of their high efficiency environmental benefits. Among the nations which are pioneering the use of fuel cells are Australia, the United States, England, Japan, Germany, Netherlands, Belgium and Canada. These countries use fuel cells to augment the capacity of and improve the reliability of power plants fueled by natural gas.

  20. Advanced fuel cell development

    NASA Astrophysics Data System (ADS)

    Pierce, R. D.; Baumert, B.; Claar, T. D.; Fousek, R. J.; Huang, H. S.; Kaun, T. D.; Krumpelt, M.; Minh, N.; Mrazek, F. C.; Poeppel, R. B.

    1985-01-01

    Fuel cell research and development activities at Argonne National Laboratory (ANL) during the period January through March 1984 are described. These efforts have been directed principally toward seeking alternative cathode materials to NiO for molten carbonate fuel cells. Based on an investigation of the thermodynamically stable phases formed under cathode conditions, a number of prospective alternative cathode materials have been identified. From the list of candidates, LiFeO2, Li2MnO3, and ZnO were selected for further investigation. During this quarter, they were doped to promote conductivity and tested for solubility and ion migration in the cell environment. An investigation directed to understanding in cell densification of anode materials was initiated. In addition, calculations were made to evaluate the practicality of controlling sulfur accumulation in molten carbonate fuel cells by bleed off of a portion of the anode gas that could be recycled to the cathode. In addition, a model is being developed to predict the performance of solid oxide fuel cells as a function of cell design and operation.

  1. Climate Change Fuel Cell Program

    SciTech Connect

    Alice M. Gitchell

    2006-09-15

    A 200 kW, natural gas fired fuel cell was installed at the Richard Stockton College of New Jersey. The purpose of this project was to demonstrate the financial and operational suitability of retrofit fuel cell technology at a medium sized college. Target audience was design professionals and the wider community, with emphasis on use in higher education. ''Waste'' heat from the fuel cell was utilized to supplement boiler operations and provide domestic hot water. Instrumentation was installed in order to measure the effectiveness of heat utilization. It was determined that 26% of the available heat was captured during the first year of operation. The economics of the fuel cell is highly dependent on the prices of electricity and natural gas. Considering only fuel consumed and energy produced (adjusted for boiler efficiency), the fuel cell saved $54,000 in its first year of operation. However, taking into account the price of maintenance and the cost of financing over the short five-year life span, the fuel cell operated at a loss, despite generous subsidies. As an educational tool and market stimulus, the fuel cell attracted considerable attention, both from design professionals and the general public.

  2. More Than 410,000 Hours of Real-World Fuel Cell System Operation Have Been Analyzed by NREL's Technology Validation Team (Fact Sheet)

    SciTech Connect

    Kurtz, J.; Wipke, K.; Sprik, S.; Ramsden, T.

    2011-02-01

    This fact sheet discusses how researchers at the National Renewable Energy Laboratory (NREL) are working to validate hydrogen and fuel cell systems in real-world settings. NREL strives to provide an independent third-party technology assessment that focuses on fuel cell system and hydrogen infrastructure performance, operation, maintenance, and safety.

  3. Effects of proton-exchange membrane fuel-cell operating conditions on charge transfer resistances measured by electrochemical impedance spectroscopy

    SciTech Connect

    Aaron, Doug S; Yiacoumi, Sotira; Tsouris, Costas

    2008-01-01

    Proton-exchange-membrane fuel cells (PEMFC) are highly dependent on operating conditions, such as humidity and temperature. This study employs electrochemical impedance spectroscopy (EIS) to measure the effects of operating parameters on internal proton and electron transport resistance mechanisms in the PEMFC. Current-density experiments have been performed to measure the power production in a 25 cm{sup 2} Nafion 117 PEMFC at varying operating conditions. These experiments have shown that low humidity and low temperature contribute to decreased power production. EIS is currently employed to provide a better understanding of the mechanisms involved in power production by calculating the specific resistances at various regions in the PEMFC. Experiments are performed at temperatures ranging from 30 to 50 C, feed humidities from 20 to 98%, and air stoichiometric ratios from 1.33 to 2.67. In all experiments, the hydrogen feed stoichiometric ratio was approximately 4.0. EIS is used to identify which transport steps limit the power production of the PEMFC over these ranges of conditions. The experimental data are analyzed via comparison to equivalent circuit models (ECMs), a technique that uses an electrical circuit to represent the electrochemical and transport properties of the PEMFC. These studies will aid in designing fuel cells that are more tolerant to wide-ranging operating conditions. In addition, optimal operating conditions for PEMFC operation can be identified.

  4. Nafion-porous cerium oxide nanotubes composite membrane for polymer electrolyte fuel cells operated under dry conditions

    NASA Astrophysics Data System (ADS)

    Ketpang, Kriangsak; Oh, Kwangjin; Lim, Sung-Chul; Shanmugam, Sangaraju

    2016-10-01

    A composite membrane operated in polymer electrolyte fuel cells (PEFCs) under low relative humidity (RH) is developed by incorporating cerium oxide nanotubes (CeNT) into a perfluorosulfonic acid (Nafion®) membrane. Porous CeNT is synthesized by direct heating a precursor impregnated polymer fibers at 500 °C under an air atmosphere. Compared to recast Nafion and commercial Nafion (NRE-212) membranes, the Nafion-CeNT composite membrane generates 1.1 times higher power density at 0.6 V, operated at 80 °C under 100% RH. Compared to Nafion-cerium oxide nanoparticles (Nafion-CeNP) membrane, the Nafion-CeNT provides 1.2 and 1.7 times higher PEFC performance at 0.6 V when operated at 80 °C under 100% and 18% RH, respectively. Additionally, the Nafion-CeNT composite membrane exhibits a good fuel cell operation under 18% RH at 80 °C. Specifically, the fluoride emission rate of Nafion-CeNT composite membrane is 20 times lower than that of the commercial NRE-212 membrane when operated under 18% RH at 80 °C for 96 h. The outstanding PEFC performance and durability operated under dry conditions is mainly attributed to the facile water diffusion capability as well as the effective hydroxyl radical scavenging property of the CeNT filler, resulting in significantly mitigating both the ohmic resistance and Nafion membrane degradation.

  5. Unitized regenerative fuel cell system

    NASA Technical Reports Server (NTRS)

    Burke, Kenneth A. (Inventor)

    2008-01-01

    A Unitized Regenerative Fuel Cell system uses heat pipes to convey waste heat from the fuel cell stack to the reactant storage tanks. The storage tanks act as heat sinks/sources and as passive radiators of the waste heat from the fuel cell stack. During charge up, i.e., the electrolytic process, gases are conveyed to the reactant storage tanks by way of tubes that include dryers. Reactant gases moving through the dryers give up energy to the cold tanks, causing water vapor in with the gases to condense and freeze on the internal surfaces of the dryer. During operation in its fuel cell mode, the heat pipes convey waste heat from the fuel cell stack to the respective reactant storage tanks, thereby heating them such that the reactant gases, as they pass though the respective dryers on their way to the fuel cell stacks retrieve the water previously removed.

  6. Comprehensive characterization and understanding of micro-fuel cells operating at high methanol concentrations

    PubMed Central

    Gago, Aldo S; Esquivel, Juan-Pablo; Sabaté, Neus; Santander, Joaquín

    2015-01-01

    Summary We report on the analysis of the performance of each electrode of an air-breathing passive micro-direct methanol fuel cell (µDMFC) during polarization, stabilization and discharge, with CH3OH (2–20 M). A reference electrode with a microcapillary was used for separately measuring the anode the cathode potential. Information about the open circuit potential (OCP), the voltage and the mass transport related phenomena are available. Using 2 M CH3OH, the anode showed mass transport problems. With 4 and 6 M CH3OH both electrodes experience this situation, whereas with 10 and 20 M CH3OH the issue is attributed to the cathode. The stabilization and fuel consumption time depends mainly on the cathode performance, which is very sensitive to fuel crossover. The exposure to 20 M CH3OH produced a loss in performance of more than 75% of the highest power density (16.3 mW·cm−2). PMID:26665070

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Fuel cell technology program

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The results of a solid polymer electrolyte fuel cell development program are summarized. A base line design was defined, and materials and components of the base line configuration were fabricated and tested. Concepts representing base line capability extensions in the areas of life, power, specific weight and volume, versatility of operation, field maintenance, and thermal control were identified and evaluated. Liaison and coordination with space shuttle contractors resulted in the exchange of engineering data.

  9. Fuel cell/gas turbine integration

    SciTech Connect

    Knickerbocker, T.

    1995-10-19

    The Allison Engine Company`s very high efficiency fuel cell/advanced turbine power cycle program is discussed. The power cycle has the following advantages: high system efficiency potential, reduced emissions inherent to fuel cells, unmanned operation(no boiler) particularly suited for distributed power, and existing product line matches fuel cell operating environment. Cost effectiveness, estimates, and projections are given.

  10. Modeling a 5 kWe planar solid oxide fuel cell based system operating on JP-8 fuel and a comparison with tubular cell based system for auxiliary and mobile power applications

    NASA Astrophysics Data System (ADS)

    Tanim, Tanvir; Bayless, David J.; Trembly, Jason P.

    2014-01-01

    A steady state planar solid oxide fuel cell (P-SOFC) based system operating on desulfurized JP-8 fuel was modeled using Aspen Plus simulation software for auxiliary and mobile power applications. An onboard autothermal reformer (ATR) employed to reform the desulfurized JP-8 fuel was coupled with the P-SOFC stack to provide for H2 and CO as fuel, minimizing the cost and complexity associated with hydrogen storage. Characterization of the ATR reformer was conducted by varying the steam to carbon ratio (H2O/C) from 0.1 to 1.0 at different ATR operating temperatures (700-800 °C) while maintaining the P-SOFC stack temperature at 850 °C. A fraction of the anode recycle was used as the steam and heat source for autothermal reforming of the JP-8 fuel, intending to make the system lighter and compact for mobile applications. System modeling revealed a maximum net AC efficiency of 37.1% at 700 °C and 29.2% at 800 °C ATR operating temperatures, respectively. Parametric analyses with respect to fuel utilization factor (Uf) and current density (j) were conducted to determine optimum operating conditions. Finally, the P-SOFC based system was compared with a previously published [1] tubular solid oxide fuel cell based (T-SOFC) system to identify the relative advantages over one another.

  11. FUEL CELL ELECTRODE MATERIALS

    DTIC Science & Technology

    FUEL CELL ELECTRODE MATERIALS. RAW MATERIAL SELECTION INFLUENCES POLARIZATION BUT IS NOT A SINGLE CONTROLLING FACTOR. AVAILABLE...DATA INDICATES THAT AN INTERRELATIONSHIP OF POROSITY, AVERAGE PORE VOLUME, AND PERMEABILITY CONTRIBUTES TO ELECTRODE FUEL CELL BEHAVIOR.

  12. Dummy Cell Would Improve Performance Of Fuel-Cell Stack

    NASA Technical Reports Server (NTRS)

    Suljak, G. T.

    1993-01-01

    Interposition of dummy cell between stack of alkaline fuel cells and accessory section of fuel-cell powerplant proposed to overcome operational deficiencies plaguing end-most active cell. Cell in combination with additional hydrogen/coolant separator plate keeps end cell warmer and drier. End cell 96th in stack of fuel cells.

  13. Dummy Cell Would Improve Performance Of Fuel-Cell Stack

    NASA Technical Reports Server (NTRS)

    Suljak, G. T.

    1993-01-01

    Interposition of dummy cell between stack of alkaline fuel cells and accessory section of fuel-cell powerplant proposed to overcome operational deficiencies plaguing end-most active cell. Cell in combination with additional hydrogen/coolant separator plate keeps end cell warmer and drier. End cell 96th in stack of fuel cells.

  14. Archaea-based microbial fuel cell operating at high ionic strength conditions.

    PubMed

    Abrevaya, Ximena C; Sacco, Natalia; Mauas, Pablo J D; Cortón, Eduardo

    2011-11-01

    In this work, two archaea microorganisms (Haloferax volcanii and Natrialba magadii) used as biocatalyst at a microbial fuel cell (MFC) anode were evaluated. Both archaea are able to grow at high salt concentrations. By increasing the media conductivity, the internal resistance was diminished, improving the MFC's performance. Without any added redox mediator, maximum power (P (max)) and current at P (max) were 11.87/4.57/0.12 μW cm(-2) and 49.67/22.03/0.59 μA cm(-2) for H. volcanii, N. magadii and E. coli, respectively. When neutral red was used as the redox mediator, P (max) was 50.98 and 5.39 μW cm(-2) for H. volcanii and N. magadii, respectively. In this paper, an archaea MFC is described and compared with other MFC systems; the high salt concentration assayed here, comparable with that used in Pt-catalyzed alkaline hydrogen fuel cells, will open new options when MFC scaling up is the objective necessary for practical applications.

  15. A niobium and tantalum co-doped perovskite cathode for solid oxide fuel cells operating below 500 °C

    NASA Astrophysics Data System (ADS)

    Li, Mengran; Zhao, Mingwen; Li, Feng; Zhou, Wei; Peterson, Vanessa K.; Xu, Xiaoyong; Shao, Zongping; Gentle, Ian; Zhu, Zhonghua

    2017-01-01

    The slow activity of cathode materials is one of the most significant barriers to realizing the operation of solid oxide fuel cells below 500 °C. Here we report a niobium and tantalum co-substituted perovskite SrCo0.8Nb0.1Ta0.1O3-δ as a cathode, which exhibits high electroactivity. This cathode has an area-specific polarization resistance as low as ~0.16 and ~0.68 Ω cm2 in a symmetrical cell and peak power densities of 1.2 and 0.7 W cm-2 in a Gd0.1Ce0.9O1.95-based anode-supported fuel cell at 500 and 450 °C, respectively. The high performance is attributed to an optimal balance of oxygen vacancies, ionic mobility and surface electron transfer as promoted by the synergistic effects of the niobium and tantalum. This work also points to an effective strategy in the design of cathodes for low-temperature solid oxide fuel cells.

  16. Aircraft Fuel Cell Power Systems

    NASA Technical Reports Server (NTRS)

    Needham, Robert

    2004-01-01

    In recent years, fuel cells have been explored for use in aircraft. While the weight and size of fuel cells allows only the smallest of aircraft to use fuel cells for their primary engines, fuel cells have showed promise for use as auxiliary power units (APUs), which power aircraft accessories and serve as an electrical backup in case of an engine failure. Fuel cell MUS are both more efficient and emit fewer pollutants. However, sea-level fuel cells need modifications to be properly used in aircraft applications. At high altitudes, the ambient air has a much lower pressure than at sea level, which makes it much more difficult to get air into the fuel cell to react and produce electricity. Compressors can be used to pressurize the air, but this leads to added weight, volume, and power usage, all of which are undesirable things. Another problem is that fuel cells require hydrogen to create electricity, and ever since the Hindenburg burst into flames, aircraft carrying large quantities of hydrogen have not been in high demand. However, jet fuel is a hydrocarbon, so it is possible to reform it into hydrogen. Since jet fuel is already used to power conventional APUs, it is very convenient to use this to generate the hydrogen for fuel-cell-based APUs. Fuel cells also tend to get large and heavy when used for applications that require a large amount of power. Reducing the size and weight becomes especially beneficial when it comes to fuel cells for aircraft. My goal this summer is to work on several aspects of Aircraft Fuel Cell Power System project. My first goal is to perform checks on a newly built injector rig designed to test different catalysts to determine the best setup for reforming Jet-A fuel into hydrogen. These checks include testing various thermocouples, transmitters, and transducers, as well making sure that the rig was actually built to the design specifications. These checks will help to ensure that the rig will operate properly and give correct results

  17. Aircraft Fuel Cell Power Systems

    NASA Technical Reports Server (NTRS)

    Needham, Robert

    2004-01-01

    In recent years, fuel cells have been explored for use in aircraft. While the weight and size of fuel cells allows only the smallest of aircraft to use fuel cells for their primary engines, fuel cells have showed promise for use as auxiliary power units (APUs), which power aircraft accessories and serve as an electrical backup in case of an engine failure. Fuel cell MUS are both more efficient and emit fewer pollutants. However, sea-level fuel cells need modifications to be properly used in aircraft applications. At high altitudes, the ambient air has a much lower pressure than at sea level, which makes it much more difficult to get air into the fuel cell to react and produce electricity. Compressors can be used to pressurize the air, but this leads to added weight, volume, and power usage, all of which are undesirable things. Another problem is that fuel cells require hydrogen to create electricity, and ever since the Hindenburg burst into flames, aircraft carrying large quantities of hydrogen have not been in high demand. However, jet fuel is a hydrocarbon, so it is possible to reform it into hydrogen. Since jet fuel is already used to power conventional APUs, it is very convenient to use this to generate the hydrogen for fuel-cell-based APUs. Fuel cells also tend to get large and heavy when used for applications that require a large amount of power. Reducing the size and weight becomes especially beneficial when it comes to fuel cells for aircraft. My goal this summer is to work on several aspects of Aircraft Fuel Cell Power System project. My first goal is to perform checks on a newly built injector rig designed to test different catalysts to determine the best setup for reforming Jet-A fuel into hydrogen. These checks include testing various thermocouples, transmitters, and transducers, as well making sure that the rig was actually built to the design specifications. These checks will help to ensure that the rig will operate properly and give correct results

  18. Fuel cell stack monitoring and system control

    DOEpatents

    Keskula, Donald H.; Doan, Tien M.; Clingerman, Bruce J.

    2004-02-17

    A control method for monitoring a fuel cell stack in a fuel cell system in which the actual voltage and actual current from the fuel cell stack are monitored. A preestablished relationship between voltage and current over the operating range of the fuel cell is established. A variance value between the actual measured voltage and the expected voltage magnitude for a given actual measured current is calculated and compared with a predetermined allowable variance. An output is generated if the calculated variance value exceeds the predetermined variance. The predetermined voltage-current for the fuel cell is symbolized as a polarization curve at given operating conditions of the fuel cell.

  19. Mobile fuel cell development at Siemens

    NASA Astrophysics Data System (ADS)

    Strasser, K.

    1992-01-01

    Recent mobile fuel cell developments are reported with particular attention given to fuel cell technology based on photon exchange membrane (PEM) as electrolyte. Advantages of PEM fuel cells over conventional systems include their overload capacity, low power degradation, long lifetime, and the possibility to operate the fuel cell at different temperatures. The PEM fuel cells can be operated with CO2-containing reactants and have a considerable potential for increasing power. These facts make it possible to construct energy storage systems with H2/air fuel cells for electric cars or long-term storage facilities for regenerative energy systems.

  20. Fuel cells for automotive applications: overview

    SciTech Connect

    McCormick, J.B.

    1980-01-01

    Projections are made of fuel cell technology for vehicular use. The fuel used to provide hydrogen to a phosphoric acid fuel cell is assumed to be methanol. Experimental performance data for a golf cart is discussed. The design, economics, and predicted performance for a fuel cell retrofitted x-car with lead-acid batteries for peaking power, are described. The technical and economic feasibility of using fuel cells in city buses, vans and passenger cars are examined. It is concluded that the fuel cell/battery hybrid vehicle will have the advantages of high efficiency, i.e., 53% improvement in fuel economy, long fuel cell life, performance comparable to IC engine vehicles, low maintenance, petroleum fuel conservation, low pollution, and quiet operation. From a comparison of the lifetime costs of conventional vehicles versus fuel cell vehicles, it is concluded that commercialization of fuel cells for buses is most feasible followed by van and automobile applications. (LCL)

  1. In situ fluorescence spectroscopy correlates ionomer degradation to reactive oxygen species generation in an operating fuel cell.

    PubMed

    Prabhakaran, Venkateshkumar; Arges, Christopher G; Ramani, Vijay

    2013-11-21

    The rate of generation of reactive oxygen species (ROS) within the polymer electrolyte membrane (PEM) of an operating proton exchange member fuel cell (PEMFC) was monitored using in situ fluorescence spectroscopy. A modified barrier layer was introduced between the PEM and the electrocatalyst layer to eliminate metal-dye interactions and fluorescence resonance energy transfer (FRET) effects during measurements. Standard fuel cell operating parameters (temperature, relative humidity, and electrode potential) were systematically varied to evaluate their influence on the rate of ROS generation during PEMFC operation. Independently, the macroscopic rate of PEM degradation was measured by monitoring the fluoride ion emission rate (FER) in the effluent stream at each operating condition. The ROS generation reaction rate constant (estimated from the in situ fluorescence experiments) correlated perfectly with the measured FER across all conditions, demonstrating unequivocally for the first time that a direct correlation exists between in situ ROS generation and PEM macroscopic degradation. The activation energy for ROS generation within the PEM was estimated to be 12.5 kJ mol(-1).

  2. Unraveling micro- and nanoscale degradation processes during operation of high-temperature polymer-electrolyte-membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Hengge, K.; Heinzl, C.; Perchthaler, M.; Varley, D.; Lochner, T.; Scheu, C.

    2017-10-01

    The work in hand presents an electron microscopy based in-depth study of micro- and nanoscale degradation processes that take place during the operation of high-temperature polymer-electrolyte-membrane fuel cells (HT-PEMFCs). Carbon supported Pt particles were used as cathodic catalyst material and the bimetallic, carbon supported Pt/Ru system was applied as anode. As membrane, cross-linked polybenzimidazole was used. Scanning electron microscopy analysis of cross-sections of as-prepared and long-term operated membrane-electrode-assemblies revealed insight into micrometer scale degradation processes: operation-caused catalyst redistribution and thinning of the membrane and electrodes. Transmission electron microscopy investigations were performed to unravel the nanometer scale phenomena: a band of Pt and Pt/Ru nanoparticles was detected in the membrane adjacent to the cathode catalyst layer. Quantification of the elemental composition of several individual nanoparticles and the overall band area revealed that they stem from both anode and cathode catalyst layers. The results presented do not demonstrate any catastrophic failure but rather intermediate states during fuel cell operation and indications to proceed with targeted HT-PEMFC optimization.

  3. LADWP FUEL CELL DEMONSTRATION PROJECT

    SciTech Connect

    Thai Ta

    2003-09-12

    Los Angeles Department of Water and Power (LADWP) is currently one of the most active power utility companies in researching fuel cell technology. Fuel cells offer many benefits and are now used as an alternative to traditional internal combustion engines in power generation. In continuing it's role as the leader in fuel cell research, LADWP has installed a pre-commercial molten carbonate fuel cell on August 2001 at its headquarter, the John Ferraro Building (JFB). The goal of this project is to learn more about the actual behavior of the fuel cell running under real world conditions. The fuel cell ran smoothly through the first year of operation with very high efficiency, but with some minor setbacks. The JFB fuel cell project is funded by the City of Los Angeles Department of Water and Power with partial grant funding from the Department of Defense's Climate Change Fuel Cell Buydown Program. The technical evaluation and the benefit-cost evaluation of the JFB fuel cell are both examined in this report.

  4. Reforming of fuel inside fuel cell generator

    DOEpatents

    Grimble, Ralph E.

    1988-01-01

    Disclosed is an improved method of reforming a gaseous reformable fuel within a solid oxide fuel cell generator, wherein the solid oxide fuel cell generator has a plurality of individual fuel cells in a refractory container, the fuel cells generating a partially spent fuel stream and a partially spent oxidant stream. The partially spent fuel stream is divided into two streams, spent fuel stream I and spent fuel stream II. Spent fuel stream I is burned with the partially spent oxidant stream inside the refractory container to produce an exhaust stream. The exhaust stream is divided into two streams, exhaust stream I and exhaust stream II, and exhaust stream I is vented. Exhaust stream II is mixed with spent fuel stream II to form a recycle stream. The recycle stream is mixed with the gaseous reformable fuel within the refractory container to form a fuel stream which is supplied to the fuel cells. Also disclosed is an improved apparatus which permits the reforming of a reformable gaseous fuel within such a solid oxide fuel cell generator. The apparatus comprises a mixing chamber within the refractory container, means for diverting a portion of the partially spent fuel stream to the mixing chamber, means for diverting a portion of exhaust gas to the mixing chamber where it is mixed with the portion of the partially spent fuel stream to form a recycle stream, means for injecting the reformable gaseous fuel into the recycle stream, and means for circulating the recycle stream back to the fuel cells.

  5. Reforming of fuel inside fuel cell generator

    DOEpatents

    Grimble, R.E.

    1988-03-08

    Disclosed is an improved method of reforming a gaseous reformable fuel within a solid oxide fuel cell generator, wherein the solid oxide fuel cell generator has a plurality of individual fuel cells in a refractory container, the fuel cells generating a partially spent fuel stream and a partially spent oxidant stream. The partially spent fuel stream is divided into two streams, spent fuel stream 1 and spent fuel stream 2. Spent fuel stream 1 is burned with the partially spent oxidant stream inside the refractory container to produce an exhaust stream. The exhaust stream is divided into two streams, exhaust stream 1 and exhaust stream 2, and exhaust stream 1 is vented. Exhaust stream 2 is mixed with spent fuel stream 2 to form a recycle stream. The recycle stream is mixed with the gaseous reformable fuel within the refractory container to form a fuel stream which is supplied to the fuel cells. Also disclosed is an improved apparatus which permits the reforming of a reformable gaseous fuel within such a solid oxide fuel cell generator. The apparatus comprises a mixing chamber within the refractory container, means for diverting a portion of the partially spent fuel stream to the mixing chamber, means for diverting a portion of exhaust gas to the mixing chamber where it is mixed with the portion of the partially spent fuel stream to form a recycle stream, means for injecting the reformable gaseous fuel into the recycle stream, and means for circulating the recycle stream back to the fuel cells. 1 fig.

  6. Fuel cell electric power production

    DOEpatents

    Hwang, Herng-Shinn; Heck, Ronald M.; Yarrington, Robert M.

    1985-01-01

    A process for generating electricity from a fuel cell includes generating a hydrogen-rich gas as the fuel for the fuel cell by treating a hydrocarbon feed, which may be a normally liquid feed, in an autothermal reformer utilizing a first monolithic catalyst zone having palladium and platinum catalytic components therein and a second, platinum group metal steam reforming catalyst. Air is used as the oxidant in the hydrocarbon reforming zone and a low oxygen to carbon ratio is maintained to control the amount of dilution of the hydrogen-rich gas with nitrogen of the air without sustaining an insupportable amount of carbon deposition on the catalyst. Anode vent gas may be utilized as the fuel to preheat the inlet stream to the reformer. The fuel cell and the reformer are preferably operated at elevated pressures, up to about a pressure of 150 psia for the fuel cell.

  7. Anode regeneration following carbon depositions in an industrial-sized anode supported solid oxide fuel cell operating on synthetic diesel reformate

    NASA Astrophysics Data System (ADS)

    Subotić, Vanja; Schluckner, Christoph; Mathe, Jörg; Rechberger, Jürgen; Schroettner, Hartmuth; Hochenauer, Christoph

    2015-11-01

    Carbon deposition is a primary concern during operation of solid oxide fuel cells (SOFCs) fueled with carbon-containing fuels. It leads to cell degradation and thus reduces SOFC sustained operation and durability. This paper reports on an experimental investigation of carbon formation on the nickel/yttria-stabilized zirconia (Ni/YSZ) anode of an anode-supported SOFC and its regeneration. The cell was fueled with a synthetically produced diesel reformate to investigate and simulate the cell behavior under real operating conditions. For this purpose the cell was operated under load to determine the critical operating time. Rapid carbon generation, such as at open circuit voltage (OCV), can be prevented when the cell is under load. Carbon depositions were detected using scanning electron microscopy (SEM) and further analyzed by Raman spectroscopy. Industrial-size cells suitable for commercial applications were studied. This study proves the reversibility of carbon formation and the reproducibility of the regeneration process. It shows that carbon formations can be recognized and effectively, fully and cell-protecting regenerated. It indicates the excellent possibility of using SOFCs in the automotive industry as an auxiliary power unit (APU) or combined power-heat unit, operated with diesel reformate, without danger from cell degradation caused by carbon-containing fuels.

  8. Fuel cell arrangement

    DOEpatents

    Isenberg, Arnold O.

    1987-05-12

    A fuel cell arrangement is provided wherein cylindrical cells of the solid oxide electrolyte type are arranged in planar arrays where the cells within a plane are parallel. Planes of cells are stacked with cells of adjacent planes perpendicular to one another. Air is provided to the interior of the cells through feed tubes which pass through a preheat chamber. Fuel is provided to the fuel cells through a channel in the center of the cell stack; the fuel then passes the exterior of the cells and combines with the oxygen-depleted air in the preheat chamber.

  9. Fuel cell arrangement

    DOEpatents

    Isenberg, A.O.

    1987-05-12

    A fuel cell arrangement is provided wherein cylindrical cells of the solid oxide electrolyte type are arranged in planar arrays where the cells within a plane are parallel. Planes of cells are stacked with cells of adjacent planes perpendicular to one another. Air is provided to the interior of the cells through feed tubes which pass through a preheat chamber. Fuel is provided to the fuel cells through a channel in the center of the cell stack; the fuel then passes the exterior of the cells and combines with the oxygen-depleted air in the preheat chamber. 3 figs.

  10. Electricity production from Azo dye wastewater using a microbial fuel cell coupled constructed wetland operating under different operating conditions.

    PubMed

    Fang, Zhou; Song, Hai-liang; Cang, Ning; Li, Xian-ning

    2015-06-15

    Microbial fuel cells (MFCs) have got tremendous attention for their capability to enhance the degradation of some recalcitrant pollutants and simultaneous electricity production. A microbial fuel cell coupled constructed wetland (CW-MFC) is a new device to treat the wastewater and produce energy which has more wastewater treatment volume and more easily to maintenance than others MFCs. The studies on the performance of CW-MFCs are necessary. In this work, the effects of hydraulic residence time (HRT), reactive brilliant red X-3B (ABRX3) proportion and COD concentration on the electricity production of CW-MFC and the degradation characteristics of ABRX3 were investigated. The decolorization rate and the electricity production increased to a peak before slowing down with the elongation of HRT. The highest decolorization rate and electricity production were obtained when HRT was 3 days. The ABRX3 proportion (calculated as COD) in the wastewater played an important role in decolorization and electricity production, which may influence the distribution of electrons in the system. The power density of CW-MFC and the decolorization rate decreased concomitantly with an increasing ABRX3 proportion. The COD concentration influenced the CW-MFC performance slightly. The highest decolorization rate and power density reached 95.6% and 0.852 W/m(3), respectively, when the COD concentration was 300 mg/L while the ABRX3 proportion was 30%. The coulombic efficiency of the CW-MFC depended on glucose and ABRX3 proportions in the wastewater. ABRX3 acquired more electrons than the anode. Further investigations are needed to optimize CW-MFC performance and explain the mechanism of biorefractory compounds degradation and electron motion in CW-MFCs.

  11. The operation of enzymatic fuel cell fabricated with rationally designed poly(caprolactone-g-ethylene glycol) copolymers.

    PubMed

    Korkut, Seyda; Kilic, Muhammet Samet; Sanal, Timur; Hazer, Baki

    2017-07-01

    This study describes construction of an enzymatic fuel cell comprised of poly(caprolactone-g-ethylene glycol) coated novel glucose oxidase anode and laccase cathode. Rationally designed poly(caprolactone-g-ethylene glycol) containing various poly(ethylene glycol) percentages ranging between 2.67 and 15.04% were synthesized chemically and tested separately for operation of the fuel cell system to achieve the best energy generation. The maximum power density was found to be 80.55μWcm(-2) at 0.91V (vs. Ag/AgCl) in pH5, 100mM citrate buffer (20°C) by the addition of 30mM of glucose from the electrodes coated with 11.34% poly(ethylene glycol) containing polymer with a quantity of 600μg. High poly(ethylene glycol) percentages with more numbers of long poly(ethylene glycol) brushes lead to the creation of a complexity in the polymer morphology and steric hindrance effect for electron transport. The graft copolymer was easily used for the fuel cell system owing to its biocompatible and microporous film morphology. The grafted polymer was able to facilitate enzymatic glucose oxidation and oxygen reduction while simultaneously producing high catalytic electrical currents. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. DIGESTER GAS - FUEL CELL - PROJECT

    SciTech Connect

    Dr.-Eng. Dirk Adolph; Dipl.-Eng. Thomas Saure

    2002-03-01

    GEW has been operating the first fuel cell in Europe producing heat and electricity from digester gas in an environmentally friendly way. The first 9,000 hours in operation were successfully concluded in August 2001. The fuel cell powered by digester gas was one of the 25 registered ''Worldwide projects'' which NRW presented at the EXPO 2000. In addition to this, it is a key project of the NRW State Initiative on Future Energies. All of the activities planned for the first year of operation were successfully completed: installing and putting the plant into operation, the transition to permanent operation as well as extended monitoring till May 2001.

  13. Open end protection for solid oxide fuel cells

    DOEpatents

    Zafred, Paolo R.; Dederer, Jeffrey T.; Tomlins, Gregory W.; Toms, James M.; Folser, George R.; Schmidt, Douglas S.; Singh, Prabhakar; Hager, Charles A.

    2001-01-01

    A solid oxide fuel cell (40) having a closed end (44) and an open end (42) operates in a fuel cell generator (10) where the fuel cell open end (42) of each fuel cell contains a sleeve (60, 64) fitted over the open end (42), where the sleeve (60, 64) extends beyond the open end (42) of the fuel cell (40) to prevent degradation of the interior air electrode of the fuel cell by fuel gas during operation of the generator (10).

  14. Recent Progress on Advanced Materials for Solid-Oxide Fuel Cells Operating Below 500 °C.

    PubMed

    Zhang, Yuan; Knibbe, Ruth; Sunarso, Jaka; Zhong, Yijun; Zhou, Wei; Shao, Zongping; Zhu, Zhonghua

    2017-06-19

    Solid-oxide fuel cells (SOFCs) are electricity generators that can convert the chemical energy in various fuels directly to the electric power with high efficiency. Recent advances in materials and related key components for SOFCs operating at ≈500 °C are summarized here, with a focus on the materials, structures, and techniques development for low-temperature SOFCs, including the analysis of most of the critical parameters affecting the electrochemical performance of the electrolyte, anode, and cathode. New strategies, such as thin-film deposition, exsolution of nanoparticles from perovskites, microwave plasma heating, and finger-like channeled electrodes, are discussed. These recent developments highlight the need for electrodes with higher activity and electrolytes with greater conductivity to generate a high electrochemical performance at lower temperatures. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Multiple cathodic reaction mechanisms in seawater cathodic biofilms operating in sediment microbial fuel cells.

    PubMed

    Babauta, Jerome T; Hsu, Lewis; Atci, Erhan; Kagan, Jeff; Chadwick, Bart; Beyenal, Haluk

    2014-10-01

    In this study, multiple reaction mechanisms in cathodes of sediment microbial fuel cells (SMFCs) were characterized by using cyclic voltammetry and microelectrode measurements of dissolved oxygen and pH. The cathodes were acclimated in SMFCs with sediment and seawater from San Diego Bay. Two limiting current regions were observed with onset potentials of approximately +400 mVAg/AgCl for limiting current I and -120 mVAg/AgCl for limiting current II. The appearance of two catalytic waves suggests that multiple cathodic reaction mechanisms influence cathodic performance. Microscale oxygen concentration measurements showed a zero surface concentration at the electrode surface for limiting current II but not for limiting current I, which allowed us to distinguish limiting current II as the conventional oxygen reduction reaction and limiting current I as a currently unidentified cathodic reaction mechanism. Microscale pH measurements further confirmed these results.

  16. Fuel cells and fuel cell catalysts

    DOEpatents

    Masel, Richard I.; Rice, Cynthia A.; Waszczuk, Piotr; Wieckowski, Andrzej

    2006-11-07

    A direct organic fuel cell includes a formic acid fuel solution having between about 10% and about 95% formic acid. The formic acid is oxidized at an anode. The anode may include a Pt/Pd catalyst that promotes the direct oxidation of the formic acid via a direct reaction path that does not include formation of a CO intermediate.

  17. Fuel Cell Handbook update

    SciTech Connect

    Owens, W.R.; Hirschenhofer, J.H.; Engleman, R.R. Jr.; Stauffer, D.B.

    1993-11-01

    The objective of this work was to update the 1988 version of DOE`s Fuel Cell Handbook. Significant developments in the various fuel cell technologies required revisions to reflect state-of-the-art configurations and performance. The theoretical presentation was refined in order to make the handbook more useful to both the casual reader and fuel cell or systems analyst. In order to further emphasize the practical application of fuel cell technologies, the system integration information was expanded. In addition, practical elements, such as suggestions and guidelines to approximate fuel cell performance, were provided.

  18. In-situ X-ray nano-CT System for Polymer Electrolyte Fuel Cells under Operating Conditions

    NASA Astrophysics Data System (ADS)

    Sekizawa, O.; Uruga, T.; Ishiguro, N.; Matsui, H.; Higashi, K.; Sakata, T.; Iwasawa, Y.; Tada, M.

    2017-06-01

    We developed two types of in-situ three-dimensional imaging systems on the basis of full-field transmission X-ray computed tomography (XCT) methods for polymer electrolyte fuel cells (PEFCs) under operating conditions at beamline BL36XU at SPring-8. One was for a wide field of view (more than 500 μm) to obtain the whole membrane electrode assembly (MEA) images, and the other was for nano spatial resolution (less than 100 nm) using a Fresnel zone plate as objective optics. We succeeded in in-situ three-dimensional visualization of an MEA in PEFC using both XCT measurement systems and show preliminary results.

  19. Fuel cell CO sensor

    DOEpatents

    Grot, Stephen Andreas; Meltser, Mark Alexander; Gutowski, Stanley; Neutzler, Jay Kevin; Borup, Rodney Lynn; Weisbrod, Kirk

    1999-12-14

    The CO concentration in the H.sub.2 feed stream to a PEM fuel cell stack is monitored by measuring current and/or voltage behavior patterns from a PEM-probe communicating with the reformate feed stream. Pattern recognition software may be used to compare the current and voltage patterns from the PEM-probe to current and voltage telltale outputs determined from a reference cell similar to the PEM-probe and operated under controlled conditions over a wide range of CO concentrations in the H.sub.2 fuel stream. A CO sensor includes the PEM-probe, an electrical discharge circuit for discharging the PEM-probe to monitor the CO concentration, and an electrical purging circuit to intermittently raise the anode potential of the PEM-probe's anode to at least about 0.8 V (RHE) to electrochemically oxidize any CO adsorbed on the probe's anode catalyst.

  20. Climate Change Fuel Cell Program

    SciTech Connect

    Paul Belard

    2006-09-21

    Verizon is presently operating the largest Distributed Generation Fuel Cell project in the USA. Situated in Long Island, NY, the power plant is composed of seven (7) fuel cells operating in parallel with the Utility grid from the Long Island Power Authority (LIPA). Each fuel cell has an output of 200 kW, for a total of 1.4 mW generated from the on-site plant. The remaining power to meet the facility demand is purchased from LIPA. The fuel cell plant is utilized as a co-generation system. A by-product of the fuel cell electric generation process is high temperature water. The heat content of this water is recovered from the fuel cells and used to drive two absorption chillers in the summer and a steam generator in the winter. Cost savings from the operations of the fuel cells are forecasted to be in excess of $250,000 per year. Annual NOx emissions reductions are equivalent to removing 1020 motor vehicles from roadways. Further, approximately 5.45 million metric tons (5 millions tons) of CO2 per year will not be generated as a result of this clean power generation. The project was partially financed with grants from the New York State Energy R&D Authority (NYSERDA) and from Federal Government Departments of Defense and Energy.

  1. Corrosion resistant PEM fuel cell

    DOEpatents

    Li, Y.; Meng, W.J.; Swathirajan, S.; Harris, S.J.; Doll, G.L.

    1997-04-29

    The present invention contemplates a PEM fuel cell having electrical contact elements (including bipolar plates/septums) comprising a titanium nitride coated light weight metal (e.g., Al or Ti) core, having a passivating, protective metal layer intermediate the core and the titanium nitride. The protective layer forms a barrier to further oxidation/corrosion when exposed to the fuel cell`s operating environment. Stainless steels rich in Cr, Ni, and Mo are particularly effective protective interlayers. 6 figs.

  2. Fueling Operational Maneuver

    DTIC Science & Technology

    1990-05-29

    is heavier than petroleum products. 7 5 TM 5-34.X p. 3-51 to 3-54 provides the basic data for this calculation. 76 David Gorczynski and David Auman ...Fast, William R. "Operational Level Support: In Search of Doctrine," Military Review, February 1988, pp. 46-52. Gorczynski, David, and David Auman

  3. Mixotrophic operation of photo-bioelectrocatalytic fuel cell under anoxygenic microenvironment enhances the light dependent bioelectrogenic activity.

    PubMed

    Chandra, Rashmi; Venkata Subhash, G; Venkata Mohan, S

    2012-04-01

    Electrogenic activity of photo-bioelectrocatalytic /photo-biological fuel cell (PhFC) was evaluated in a mixotrophic mode under anoxygenic microenvironment using photosynthetic consortia as biocatalyst. An acetate rich wastewater was used as anolyte for harnessing energy along with additional treatment. Mixotrophic operation facilitated good electrogenic activity and wastewater treatment associated with biomass growth. PhFC operation documented feasible microenvironment for the growth of photosynthetic bacteria compared to algae which was supported by pigment (total chlorophyll and bacteriochlorophyll) and diversity analysis. Pigment data also illustrated the association between bacterial and algal species. The synergistic interaction between anoxygenic and oxygenic photosynthesis was found to be suitable for PhFC operation. Light dependent deposition of electrons at electrode was relatively higher compared to dark dependent electron deposition under anoxygenic condition. PhFC documented for good volatile fatty acids removal by utilizing them as electron donor. Bioelectrochemical behavior of PhFC was evaluated by voltammetric and chronoamperometry analysis.

  4. Direct-fuelled fuel cells

    NASA Astrophysics Data System (ADS)

    Waidhas, M.; Drenckhahn, W.; Preidel, W.; Landes, H.

    Fuel supply is one important problem to be solved for commercial application of fuel cell technology. Conventional fuel-cell types require hydrogen as the fuel, which has to be free from impurities when operated at temperatures below 100 °C. The storage and distribution of this explosive and extremely fugitive gas is one of the open questions in the context of a customer-oriented broad commercial market. The direct-fuelled fuel cells (DMFCs) overcome the hydrogen specific restrictions. They are capable of directly using natural gas or fuels which are liquid under ambient conditions. In this paper the different options from direct-fuelled systems are described and their general aspects discussed. The state-of-the-art at Siemens in this field, and also the remaining technical questions are outlined as a basis for assessing future applications.

  5. A flexible all-inorganic fuel cell membrane with conductivity above Nafion, and durable operation at 150 °C

    NASA Astrophysics Data System (ADS)

    Ansari, Y.; Tucker, T. G.; Huang, W.; Klein, I. S.; Lee, S.-Y.; Yarger, J. L.; Angell, C. A.

    2016-01-01

    The search for fuel cell membranes has focused on carbon backbone polymers, among which Nafion seems to best survive the most severe of the degradation mechanisms - attack by peroxide radicals. Less attention has been given to inorganic membranes because of their generally inflexible nature and lower conductivity, though some SiO2-Nafion composites have shown improved properties. Nafion dominates, despite needing hydration, which then restricts operation to below 100 °C (so CO poisoning problems persist). Described herein is a low cost, flexible, and all-inorganic fiberglass reinforced gel membrane with conductivity exceeding that of Nafion at any temperature above 60 °C. Using Teflon fuel cells, maximum currents > 1 Acm-2 and OCV of 1.03 V at 150 °C are demonstrated. No detectable loss of cell potential was observed over 24 h during 50 mAcm-2 constant current operation at 120 °C while, at 150 °C and maximum power, the degradation rate is intermediate among other high conductivity H3PO4-PBI type membranes. The structure of the membrane is deduced, mainly from 29Si solid state-NMR. The -115 ppm resonance, which is extreme for Q4 Si(O) structures, identifies a zeolite-like SiO2 network, which is "floppy". 31P and 1H NMR establish nano-permeating H3PO4 as the source of the exceptional conductivity.

  6. On-demand supply of slurry fuels to a porous anode of a direct carbon fuel cell: Attempts to increase fuel-anode contact and realize long-term operation

    NASA Astrophysics Data System (ADS)

    Li, Chengguo; Yi, Hakgyu; Lee, Donggeun

    2016-03-01

    In this paper, we propose a novel idea that might allow resolution of the two biggest challenges that hinder practical use of direct carbon fuel cells (DCFC). This work involved 1) the use of three types of porous Ni anode with different pore sizes, 2) size matching between the anode pores and solid fuel particles in a molten-carbonate (MC) slurry, and 3) provision of a continuous supply of fuel-MC slurry through the porous Ni anode. As a result, larger numbers of smaller pores in the anode were preferred for extending the triple phase boundary (TPB), as long as the fuel particles were sufficiently small to have full access to the inner pore spaces of the anode. For example, the maximal power density achieved in the case of optimal size matching, reached 645 mW cm-2, which is 14-times greater than that for the case of poorest size-matching and 64-times larger than that for a non-porous anode, and lasted for more than 20 h. After 20 h of steady operation at a fixed current density (700 mA cm-2), the electric potential slightly decreased due to partial consumption of the fuel. The cell performance readily recovered after restarting the supply of MC-fuel slurry.

  7. Fuel cell generator

    DOEpatents

    Isenberg, Arnold O.

    1983-01-01

    High temperature solid oxide electrolyte fuel cell generators which allow controlled leakage among plural chambers in a sealed housing. Depleted oxidant and fuel are directly reacted in one chamber to combust remaining fuel and preheat incoming reactants. The cells are preferably electrically arranged in a series-parallel configuration.

  8. Acoustic emission: Towards a real-time diagnosis technique for Proton Exchange Membrane Fuel Cell operation

    NASA Astrophysics Data System (ADS)

    Legros, B.; Thivel, P.-X.; Bultel, Y.; Boinet, M.; Nogueira, R. P.

    This paper deals with one of the needs for PEMFC to be economically reliable: diagnosis tool for water management. This issue is actually a key parameter for both performance and durability improvement. Acoustic emission (AE) technique was employed to survey PEM single cell under various operating conditions. AE events coming from different sources have thus been identified, classified and finally ascribed to different phenomena induced by MEA water uptake and/or biphasic flow in the gas channel thanks to a statistical post-treatment of the acoustic data. Results, although qualitative, seems trusty enough to unravel hidden correlations between AE hits and physicochemical phenomena taking place during the cell operation and open up the way for an innovative and non-invasive online diagnosis tool.

  9. TESTING AND PERFORMANCE ANALYSIS OF NASA 5 CM BY 5 CM BI-SUPPORTED SOLID OXIDE ELECTROLYSIS CELLS OPERATED IN BOTH FUEL CELL AND STEAM ELECTROLYSIS MODES

    SciTech Connect

    R. C. O'Brien; J. E. O'Brien; C. M. Stoots; X. Zhang; S. C. Farmer; T. L. Cable; J. A. Setlock

    2011-11-01

    A series of 5 cm by 5 cm bi-supported Solid Oxide Electrolysis Cells (SOEC) were produced by NASA for the Idaho National Laboratory (INL) and tested under the INL High Temperature Steam Electrolysis program. The results from the experimental demonstration of cell operation for both hydrogen production and operation as fuel cells is presented. An overview of the cell technology, test apparatus and performance analysis is also provided. The INL High Temperature Steam Electrolysis laboratory has developed significant test infrastructure in support of single cell and stack performance analyses. An overview of the single cell test apparatus is presented. The test data presented in this paper is representative of a first batch of NASA's prototypic 5 cm by 5 cm SOEC single cells. Clearly a significant relationship between the operational current density and cell degradation rate is evident. While the performance of these cells was lower than anticipated, in-house testing at NASA Glenn has yielded significantly higher performance and lower degradation rates with subsequent production batches of cells. Current post-test microstructure analyses of the cells tested at INL will be published in a future paper. Modification to cell compositions and cell reduction techniques will be altered in the next series of cells to be delivered to INL with the aim to decrease the cell degradation rate while allowing for higher operational current densities to be sustained. Results from the testing of new batches of single cells will be presented in a future paper.

  10. Effects of operating conditions on durability of polymer electrolyte membrane fuel cell Pt cathode catalyst layer

    NASA Astrophysics Data System (ADS)

    Ohyagi, Shinsuke; Matsuda, Toshihiko; Iseki, Yohei; Sasaki, Tatsuyoshi; Kaito, Chihiro

    In this study, we investigated the effects of humidity and oxygen reduction on the degradation of the catalyst of a polymer electrolyte membrane fuel cell (PEMFC) in a voltage cycling test. To elucidate the effect of humidity on the voltage cycling corrosion of a carbon-supported Pt catalyst with 3 nm Pt particles, voltage cycling tests based on 10,000 cycles were conducted using 100% relative humidity (RH) hydrogen as anode gas and nitrogen of varying humidities as cathode gas. The degradation rate of an electrochemical surface area (ECSA) was almost 50% under 189% RH nitrogen atmosphere and the Pt average particle diameter after 10,000 cycles under these conditions was about 2.3 times that of a particle of fresh catalyst because of the agglomeration of Pt particles. The oxygen reduction reaction (ORR) that facilitated Pt catalyst agglomeration when oxygen was employed as the cathode gas also demonstrated that Pt agglomeration was prominent in higher concentrations of oxygen. The ECSA degradation figure in 100% RH oxygen was similar to that in 189% RH nitrogen. It was concluded that liquid water, which was dropped under a supersaturated condition or generated by ORR, accelerated Pt agglomeration. In this paper, we suggest that the Pt agglomeration degradation occurs in a flooding area in a cell plane.

  11. An economic feasibility analysis of distributed electric power generation based upon the Natural Gas-Fired Fuel Cell: a model of the operations cost.

    SciTech Connect

    Not Available

    1993-06-30

    This model description establishes the revenues, expenses incentives and avoided costs of Operation of a Natural Gas-Fired Fuel Cell-Based. Fuel is the major element of the cost of operation of a natural gas-fired fuel cell. Forecasts of the change in the price of this commodity a re an important consideration in the ownership of an energy conversion system. Differences between forecasts, the interests of the forecaster or geographical areas can all have significant effects on imputed fuel costs. There is less effect on judgments made on the feasibility of an energy conversion system since changes in fuel price can affect the cost of operation of the alternatives to the fuel cell in a similar fashion. The forecasts used in this model are only intended to provide the potential owner or operator with the means to examine alternate future scenarios. The operations model computes operating costs of a system suitable for a large condominium complex or a residential institution such as a hotel, boarding school or prison. The user may also select large office buildings that are characterized by 12 to 16 hours per day of operation or industrial users with a steady demand for thermal and electrical energy around the clock.

  12. Automotive Fuel Processor Development and Demonstration with Fuel Cell Systems

    SciTech Connect

    Nuvera Fuel Cells

    2005-04-15

    The potential for fuel cell systems to improve energy efficiency and reduce emissions over conventional power systems has generated significant interest in fuel cell technologies. While fuel cells are being investigated for use in many applications such as stationary power generation and small portable devices, transportation applications present some unique challenges for fuel cell technology. Due to their lower operating temperature and non-brittle materials, most transportation work is focusing on fuel cells using proton exchange membrane (PEM) technology. Since PEM fuel cells are fueled by hydrogen, major obstacles to their widespread use are the lack of an available hydrogen fueling infrastructure and hydrogen's relatively low energy storage density, which leads to a much lower driving range than conventional vehicles. One potential solution to the hydrogen infrastructure and storage density issues is to convert a conventional fuel such as gasoline into hydrogen onboard the vehicle using a fuel processor. Figure 2 shows that gasoline stores roughly 7 times more energy per volume than pressurized hydrogen gas at 700 bar and 4 times more than liquid hydrogen. If integrated properly, the fuel processor/fuel cell system would also be more efficient than traditional engines and would give a fuel economy benefit while hydrogen storage and distribution issues are being investigated. Widespread implementation of fuel processor/fuel cell systems requires improvements in several aspects of the technology, including size, startup time, transient response time, and cost. In addition, the ability to operate on a number of hydrocarbon fuels that are available through the existing infrastructure is a key enabler for commercializing these systems. In this program, Nuvera Fuel Cells collaborated with the Department of Energy (DOE) to develop efficient, low-emission, multi-fuel processors for transportation applications. Nuvera's focus was on (1) developing fuel processor

  13. Small stack performance of intermediate temperature-operating solid oxide fuel cells using stainless steel interconnects and anode-supported single cell

    NASA Astrophysics Data System (ADS)

    Bae, Joongmyeon; Lim, Sungkwang; Jee, Hyunjin; Kim, Jung Hyun; Yoo, Young-Sung; Lee, Taehee

    We are developing 1 kW class solid oxide fuel cell (SOFC) system for residential power generation (RPG) application supported by Korean Government. Anode-supported single cells with thin electrolyte layer of YSZ (yttria-stabilized zirconia) or ScSZ (scandia-stabilized zirconia) for intermediate temperature operation (650-750 °C), respectively, were fabricated and small stacks were built and evaluated. The LSCF/ScSZ/Ni-YSZ single cell showed performance of 543 mW cm -2 at 650 °C and 1680 mW cm -2 at 750 °C. The voltage of 15-cell stack based on 5 cm × 5 cm single cell (LSM/YSZ/Ni-YSZ) at 150 mW was 12.5 V in hydrogen as fuel of 120 sccm per cell at 750 °C and decreased to about 10.9 V at 500 h operation time. A 5-cell stack based on the LSCF/YSZ/FL/Ni-YSZ showed the maximum power density of 30 W, 25 W and 20 W at 750 °C, 700 °C and 650 °C, respectively. LSCF/ScSZ/Ni-YSZ-based stack showed better performance than LSCF/YSZ/Ni-YSZ stack from the experiment temperature range. I- V characteristics by using hydrogen gas and reformate gas of methane as fuel were investigated at 750 °C in LSCF/ScSZ/FL/Ni-YSZ-based 5-cell stack.

  14. Long-term testing of a high-temperature proton exchange membrane fuel cell short stack operated with improved polybenzimidazole-based composite membranes

    NASA Astrophysics Data System (ADS)

    Pinar, F. Javier; Cañizares, Pablo; Rodrigo, Manuel A.; Úbeda, Diego; Lobato, Justo

    2015-01-01

    In this work, the feasibility of a 150 cm2 high-temperature proton exchange membrane fuel cell (HT-PEMFC) stack operated with modified proton exchange membranes is demonstrated. The short fuel cell stack was manufactured using a total of three 50 cm2 membrane electrode assemblies (MEAs). The PEM technology is based on a polybenzimidazole (PBI) membrane. The obtained results were compared with those obtained using a HT-PEMFC stack with unmodified membranes. The membranes were cast from a PBI polymer synthesized in the laboratory, and the modified membranes contained 2 wt.% micro-sized TiO2 as a filler. Long-term tests were performed in both constant and dynamic loading modes. The fuel cell stack with 2 wt.% TiO2 composite PBI membranes exhibited an irreversible voltage loss of less than 2% after 1100 h of operation. In addition, the acid loss was reduced from 2% for the fuel cell stack with unmodified membranes to 0.6% for the fuel cell stack with modified membranes. The results demonstrate that introducing filler into the membranes enhances the durability and stability of this type of fuel cell technology. Moreover, the fuel cell stack system also exhibits very rapid and stable power and voltage output responses under dynamic load regimes.

  15. Self-sustained operation of a kW e-class kerosene-reforming processor for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Yoon, Sangho; Bae, Joongmyeon; Kim, Sunyoung; Yoo, Young-Sung

    In this paper, fuel-processing technologies are developed for application in residential power generation (RPG) in solid oxide fuel cells (SOFCs). Kerosene is selected as the fuel because of its high hydrogen density and because of the established infrastructure that already exists in South Korea. A kerosene fuel processor with two different reaction stages, autothermal reforming (ATR) and adsorptive desulfurization reactions, is developed for SOFC operations. ATR is suited to the reforming of liquid hydrocarbon fuels because oxygen-aided reactions can break the aromatics in the fuel and steam can suppress carbon deposition during the reforming reaction. ATR can also be implemented as a self-sustaining reactor due to the exothermicity of the reaction. The kW e self-sustained kerosene fuel processor, including the desulfurizer, operates for about 250 h in this study. This fuel processor does not require a heat exchanger between the ATR reactor and the desulfurizer or electric equipment for heat supply and fuel or water vaporization because a suitable temperature of the ATR reformate is reached for H 2S adsorption on the ZnO catalyst beds in desulfurizer. Although the CH 4 concentration in the reformate gas of the fuel processor is higher due to the lower temperature of ATR tail gas, SOFCs can directly use CH 4 as a fuel with the addition of sufficient steam feeds (H 2O/CH 4 ≥ 1.5), in contrast to low-temperature fuel cells. The reforming efficiency of the fuel processor is about 60%, and the desulfurizer removed H 2S to a sufficient level to allow for the operation of SOFCs.

  16. Mathematical model for the analysis of structure and optimal operational parameters of a solid oxide fuel cell generator

    NASA Astrophysics Data System (ADS)

    Coralli, Alberto; Villela de Miranda, Hugo; Espiúca Monteiro, Carlos Felipe; Resende da Silva, José Francisco; Valadão de Miranda, Paulo Emílio

    2014-12-01

    Solid oxide fuel cells are globally recognized as a very promising technology in the area of highly efficient electricity generation with a low environmental impact. This technology can be advantageously implemented in many situations in Brazil and it is well suited to the use of ethanol as a primary energy source, an important feature given the highly developed Brazilian ethanol industry. In this perspective, a simplified mathematical model is developed for a fuel cell and its balance of plant, in order to identify the optimal system structure and the most convenient values for the operational parameters, with the aim of maximizing the global electric efficiency. In this way it is discovered the best operational configuration for the desired application, which is the distributed generation in the concession area of the electricity distribution company Elektro. The data regarding this configuration are required for the continuation of the research project, i.e. the development of a prototype, a cost analysis of the developed system and a detailed perspective of the market opportunities in Brazil.

  17. Increased power generation from primary sludge by a submersible microbial fuel cell and optimum operational conditions.

    PubMed

    Vologni, Valentina; Kakarla, Ramesh; Angelidaki, Irini; Min, Booki

    2013-05-01

    Microbial fuel cells (MFCs) have received attention as a promising renewable energy technology for waste treatment and energy recovery. We tested a submersible MFC with an innovative design capable of generating a stable voltage of 0.250 ± 0.008 V (with a fixed 470 Ω resistor) directly from primary sludge. In a polarization test, the maximum power density was 0.18 W/m(2) at a current density of 0.8 A/m(2) with an external resistor of 300 Ω. The anodic solution of the primary sludge needs to be adjusted to a pH 7 for high power generation. The modified primary sludge with an added phosphate buffer prolonged the current generation and increased the power density by 7 and 1.5 times, respectively, in comparison with raw primary sludge. These findings suggest that energy recovery from primary sludge can be maximized using an advanced MFC system with optimum conditions.

  18. Optimal operation management of fuel cell/wind/photovoltaic power sources connected to distribution networks

    NASA Astrophysics Data System (ADS)

    Niknam, Taher; Kavousifard, Abdollah; Tabatabaei, Sajad; Aghaei, Jamshid

    2011-10-01

    In this paper a new multiobjective modified honey bee mating optimization (MHBMO) algorithm is presented to investigate the distribution feeder reconfiguration (DFR) problem considering renewable energy sources (RESs) (photovoltaics, fuel cell and wind energy) connected to the distribution network. The objective functions of the problem to be minimized are the electrical active power losses, the voltage deviations, the total electrical energy costs and the total emissions of RESs and substations. During the optimization process, the proposed algorithm finds a set of non-dominated (Pareto) optimal solutions which are stored in an external memory called repository. Since the objective functions investigated are not the same, a fuzzy clustering algorithm is utilized to handle the size of the repository in the specified limits. Moreover, a fuzzy-based decision maker is adopted to select the 'best' compromised solution among the non-dominated optimal solutions of multiobjective optimization problem. In order to see the feasibility and effectiveness of the proposed algorithm, two standard distribution test systems are used as case studies.

  19. Low cost, lightweight fuel cell elements

    NASA Technical Reports Server (NTRS)

    Kindler, Andrew (Inventor)

    2001-01-01

    New fuel cell elements for use in liquid feed fuel cells are provided. The elements including biplates and endplates are low in cost, light in weight, and allow high efficiency operation. Electrically conductive elements are also a part of the fuel cell elements.

  20. Fuel cell system for transportation applications

    DOEpatents

    Kumar, R.; Ahmed, S.; Krumpelt, M.; Myles, K.M.

    1993-09-28

    A propulsion system is described for a vehicle having pairs of front and rear wheels and a fuel tank. An electrically driven motor having an output shaft operatively connected to at least one of said pair of wheels is connected to a fuel cell having a positive electrode and a negative electrode separated by an electrolyte for producing dc power to operate the motor. A partial oxidation reformer is connected both to the fuel tank and to the fuel cell and receives hydrogen-containing fuel from the fuel tank and uses water and air for partially oxidizing and reforming the fuel in the presence of an oxidizing catalyst and a reforming catalyst to produce a hydrogen-containing gas. The hydrogen-containing gas is sent from the partial oxidation reformer to the fuel cell negative electrode while air is transported to the fuel cell positive electrode to produce dc power for operating the electric motor. 3 figures.

  1. Fuel cell system for transportation applications

    DOEpatents

    Kumar, Romesh; Ahmed, Shabbir; Krumpelt, Michael; Myles, Kevin M.

    1993-01-01

    A propulsion system for a vehicle having pairs of front and rear wheels and a fuel tank. An electrically driven motor having an output shaft operatively connected to at least one of said pair of wheels is connected to a fuel cell having a positive electrode and a negative electrode separated by an electrolyte for producing dc power to operate the motor. A partial oxidation reformer is connected both to the fuel tank and to the fuel cell receives hydrogen-containing fuel from the fuel tank and water and air and for partially oxidizing and reforming the fuel with water and air in the presence of an oxidizing catalyst and a reforming catalyst to produce a hydrogen-containing gas. The hydrogen-containing gas is sent from the partial oxidation reformer to the fuel cell negative electrode while air is transported to the fuel cell positive electrode to produce dc power for operating the electric motor.

  2. Improved fuel cell system for transportation applications

    SciTech Connect

    Kumar, R.; Ahmed, S.; Krumpelt, M.; Myles, M.K.

    1991-12-31

    This invention is comprised of a propulsion system for a vehicle having pairs of front and rear wheels and a fuel tank. An electrically driven motor having an output shaft operatively connected to at least one of said pair of wheels is connected to a fuel cell having a positive electrode and a negative electrode separated by an electrolyte for producing dc power to operate the motor. A partial oxidation reformer is connected both to the fuel tank and to the fuel cell receives hydrogen-containing fuel from the fuel tank and water and air and for partially oxidizing and reforming the fuel with water and air in the presence of an oxidizing catalyst and a reforming catalyst to produce a hydrogen-containing gas. The hydrogen-containing gas is sent from the partial oxidation reformer to the fuel cell negative electrode while air is transported to the fuel cell positive electrode to produce dc power for operating the electric motor.

  3. Proton exchange membrane fuel cell reversible performance loss induced by carbon monoxide produced during operation

    NASA Astrophysics Data System (ADS)

    Decoopman, B.; Vincent, R.; Rosini, S.; Paganelli, G.; Thivel, P.-X.

    2016-08-01

    Cyclic voltammetry measurements at the anode have been carried out and reveal the presence of carbon monoxide in steady-state operation, with pure hydrogen. Experiments have been performed both in single cell and in stack to find out its origin. The contamination of the anode catalyst is partly due the reverse-water gas shift (RWGS) with carbon dioxide from the cathode. However, this study shows a temperature-activated and time-related corrosion mechanism which appears under humidified hydrogen. Due to this degradation mechanism, a reversible 25 mV-loss of performances is observed and can be recovered by oxidizing carbon monoxide on the anode.

  4. Operando fuel cell spectroscopy

    NASA Astrophysics Data System (ADS)

    Kendrick, Ian Michael

    The active state of a catalyst only exists during catalysis (1) provided the motivation for developing operando spectroscopic techniques. A polymer electrolyte membrane fuel cell (PEMFC) was designed to interface with commercially available instruments for acquisition of infrared spectra of the catalytic surface of the membrane electrode assembly (MEA) during normal operation. This technique has provided insight of the complex processes occurring at the electrode surface. Nafion, the solid electrolyte used in most modern-day polymer electrolyte membrane fuel cells (PEMFC), serves many purposes in fuel cell operation. However, there is little known of the interface between Nafion and the electrode surface. Previous studies of complex Stark tuning curves of carbon monoxide on the surface of a platinum electrode were attributed the co-adsorption of bisulfite ions originating from the 0.5M H2SO4 electrolyte used in the study(2). Similar tuning curves obtained on a fuel cell MEA despite the absence of supplemental electrolytes suggest the adsorption of Nafion onto platinum (3). The correlation of spectra obtained using attenuated total reflectance spectroscopy (ATR) and polarization modulated IR reflection-absorption spectroscopy (PM-IRRAS) to a theoretical spectrum generated using density functional theory (DFT) lead to development of a model of Nafion and platinum interaction which identified participation of the SO3- and CF3 groups in Nafion adsorption. The use of ethanol as a fuel stream in proton exchange membrane fuel cells provides a promising alternative to methanol. Relative to methanol, ethanol has a greater energy density, lower toxicity and can be made from the fermentation of biomass(4). Operando IR spectroscopy was used to study the oxidation pathway of ethanol and Stark tuning behavior of carbon monoxide on Pt, Ru, and PtRu electrodes. Potential dependent products such as acetaldehyde, acetic acid and carbon monoxide are identified as well as previously

  5. Corrosion resistant PEM fuel cell

    DOEpatents

    Li, Yang; Meng, Wen-Jin; Swathirajan, Swathy; Harris, Stephen J.; Doll, Gary L.

    1997-01-01

    The present invention contemplates a PEM fuel cell having electrical contact elements (including bipolar plates/septums) comprising a titanium nitride coated light weight metal (e.g., Al or Ti) core, having a passivating, protective metal layer intermediate the core and the titanium nitride. The protective layer forms a barrier to further oxidation/corrosion when exposed to the fuel cell's operating environment. Stainless steels rich in CR, Ni, and Mo are particularly effective protective interlayers.

  6. Corrosion resistant PEM fuel cell

    DOEpatents

    Li, Yang; Meng, Wen-Jin; Swathirajan, Swathy; Harris, Stephen Joel; Doll, Gary Lynn

    2001-07-17

    The present invention contemplates a PEM fuel cell having electrical contact elements (including bipolar plates/septums) comprising a titanium nitride coated light weight metal (e.g., Al or Ti) core, having a passivating, protective metal layer intermediate the core and the titanium nitride. The protective layer forms a barrier to further oxidation/corrosion when exposed to the fuel cell's operating environment. Stainless steels rich in CR, Ni, and Mo are particularly effective protective interlayers.

  7. Corrosion resistant PEM fuel cell

    DOEpatents

    Li, Yang; Meng, Wen-Jin; Swathirajan, Swathy; Harris, Stephen Joel; Doll, Gary Lynn

    2002-01-01

    The present invention contemplates a PEM fuel cell having electrical contact elements (including bipolar plates/septums) comprising a titanium nitride coated light weight metal (e.g., Al or Ti) core, having a passivating, protective metal layer intermediate the core and the titanium nitride. The protective layer forms a barrier to further oxidation/corrosion when exposed to the fuel cell's operating environment. Stainless steels rich in CR, Ni, and Mo are particularly effective protective interlayers.

  8. The influence of operating temperature on the efficiency of a combined heat and power fuel cell plant

    NASA Astrophysics Data System (ADS)

    Au, S. F.; McPhail, S. J.; Woudstra, N.; Hemmes, K.

    It is generally accepted that the ideal operating temperature of a molten carbonate fuel cell (MCFC) is 650 °C. Nevertheless, when waste heat utilization in the form of an expander and steam production cycle is introduced in the system, another temperature level might prove more productive. This article is a first attempt to the optimization of MCFC operating temperatures of a MCFC system by presenting a case study in which the efficiency of a combined heat and power (CHP) plant is analyzed. The fuel cell plant under investigation is designed around a 250 kW-class MCFC fuelled by natural gas, which is externally reformed by a heat exchange reformer (HER). The operating temperature of the MCFC is varied over a temperature range between 600 and 700 °C while keeping the rest of the system the same as far as possible. Changes in energetic efficiency are given and the causes of these changes are further analyzed. Furthermore, the exergetic efficiencies of the system and the distribution of exergy losses in the system are given. Flowsheet calculations show that there is little dependency on the temperature in the first order. Both the net electrical performance and the overall exergetic performance show a maximum at approximately 675 °C, with an electrical efficiency of 51.9% (LHV), and an exergy efficiency of 58.7%. The overall thermal efficiency of this CHP plant increases from 87.1% at 600 °C to 88.9% at 700 °C. Overall, the change in performance is small in this typical range of MCFC operating temperature.

  9. Fuel cell market applications

    SciTech Connect

    Williams, M.C.

    1995-12-31

    This is a review of the US (and international) fuel cell development for the stationary power generation market. Besides DOE, GRI, and EPRI sponsorship, the US fuel cell program has over 40% cost-sharing from the private sector. Support is provided by user groups with over 75 utility and other end-user members. Objectives are to develop and demonstrate cost-effective fuel cell power generation which can initially be commercialized into various market applications using natural gas fuel by the year 2000. Types of fuel cells being developed include PAFC (phosphoric acid), MCFC (molten carbonate), and SOFC (solid oxide); status of each is reported. Potential international applications are reviewed also. Fuel cells are viewed as a force in dispersed power generation, distributed power, cogeneration, and deregulated industry. Specific fuel cell attributes are discussed: Fuel cells promise to be one of the most reliable power sources; they are now being used in critical uninterruptible power systems. They need hydrogen which can be generated internally from natural gas, coal gas, methanol landfill gas, or other fuels containing hydrocarbons. Finally, fuel cell development and market applications in Japan are reviewed briefly.

  10. PEM Fuel Cell Mechanisms and Processes

    NASA Astrophysics Data System (ADS)

    Wilson, Mahlon

    2000-03-01

    A fuel cell produces electrical energy via an electrochemical reaction. Unlike a conventional battery, the "fuel" and oxidant are supplied to the device from external sources. The device can thus be operated until the fuel (or oxidant) supply is exhausted, which can provide very high energy densities for the overall system. Historically, fuel cells have been of principle interest to the space program because of their high intrinsic conversion efficiencies and benign reaction product (water). Because of these various advantages and ever increasing environmental concerns, most types of fuel cells are attracting greater commercial and government interest. However, the popularity of a relatively new type of fuel cell, the polymer electrolyte membrane (PEM) fuel cell, is rapidly outpacing the others. Unlike most other types of fuel cells, which use liquid electrolytes, the PEM fuel cell uses a quasi-solid electrolyte based on a polymer backbone with side-chains possessing acid-based groups. The numerous advantages of this family of electrolytes make the PEM fuel cell particularly attractive for smaller scale terrestrial applications such as transportation, home-based distributed power, and portable power applications. Despite the many advantages, the conventional PEM introduces some unique challenges that significantly impact the design and operation of PEM-based fuel cells. In this presentation, an overview of PEM fuel cells will be provided starting with the fundamental principles on through the contributions and characteristics of the key components, the basics of PEM fuel cell operation, the considerations of various applications and the ramifications on system design.

  11. Fuel cell technology: A sweeter fuel

    NASA Astrophysics Data System (ADS)

    Kendall, Kevin

    2002-12-01

    Eating sugar gives us a boost when we feel tired because our cells use it as fuel to produce energy. Likewise, sugar can now be used to produce power in artificial biological fuel cells that function in a physiological environment.

  12. Stabilized composite membranes and membrane electrode assemblies for high temperature/low relative humidity polymer electrolyte fuel cell operation

    NASA Astrophysics Data System (ADS)

    Ramani, Vijay Krishna

    Polymer electrolyte membrane fuel cells (PEMFCs) have a variety of applications in the stationary power, mobile power and automotive power sectors. Existing membrane technology presently permits fuel cell operation at temperatures less than 100°C under fully saturated conditions. However, several advantages such as easier heat rejection rates and improved impurities tolerance by the anode electrocatalyst result by operating a PEMFC at elevated temperatures (above 100°C) and lower relative humidities. In an attempt to extend the operating range of the polymer electrolyte membrane, perfluorosulfonic acid (NafionRTM) based organic/inorganic (heteropolyacid) composite membranes were investigated in terms of thermal and electrochemical stability, additive stability and conductivity. Tungsten based heteropolyacids (HPAs) were found to be electrochemically stable as opposed to molybdenum based additives. The stability of the inorganic heteropolyacid additive in aqueous environments was enhanced by ion exchanging the protons of the HPAs with larger counter ions. An additional stabilization technique developed involved improving the interaction of HPA with NafionRTM by linking the particles to the sulfonic acid clusters via a sol-gel induced metal oxide linkage. The proton conductivity of the composite membranes was found to depend on the particle size of the HPA additive. A two order of magnitude change in additive particle size was attained by modification of the membrane preparation technique. This modification resulted in a nearly 50% increase in conductivity. The membranes prepared were characterized by thermal analysis, spectroscopy and microscopy. A technique was developed to incorporate existing MEA preparation and HPA stabilization techniques to the composite membranes with small HPA particles. All MEAs prepared were evaluated at high temperatures (120°C) and low relative humidities (35%) in an operating fuel cell, with membrane resistance and hence conductivity

  13. Dry gas operation of proton exchange membrane fuel cells with parallel channels: Non-porous versus porous plates

    NASA Astrophysics Data System (ADS)

    Litster, Shawn; Santiago, Juan G.

    We present a study of proton exchange membrane (PEM) fuel cells with parallel channel flow fields for the cathode, dry inlet gases, and ambient pressure at the outlets. The study compares the performance of two designs: a standard, non-porous graphite cathode plate design and a porous hydrophilic carbon plate version. The experimental study of the non-porous plate is a control case and highlights the significant challenges of operation with dry gases and non-porous, parallel channel cathodes. These challenges include significant transients in power density and severe performance loss due to flooding and electrolyte dry-out. Our experimental study shows that the porous plate yields significant improvements in performance and robustness of operation. We hypothesize that the porous plate distributes water throughout the cell area by capillary action; including pumping water upstream to normally dry inlet regions. The porous plate reduces membrane resistance and air pressure drop. Further, IR-free polarization curves confirm operation free of flooding. With an air stoichiometric ratio of 1.3, we obtain a maximum power density of 0.40 W cm -2, which is 3.5 times greater than that achieved with the non-porous plate at the same operating condition.

  14. Micro-Tubular Fuel Cells

    NASA Technical Reports Server (NTRS)

    Kimble, Michael C.; Anderson, Everett B.; Jayne, Karen D.; Woodman, Alan S.

    2004-01-01

    Micro-tubular fuel cells that would operate at power levels on the order of hundreds of watts or less are under development as alternatives to batteries in numerous products - portable power tools, cellular telephones, laptop computers, portable television receivers, and small robotic vehicles, to name a few examples. Micro-tubular fuel cells exploit advances in the art of proton-exchange-membrane fuel cells. The main advantage of the micro-tubular fuel cells over the plate-and-frame fuel cells would be higher power densities: Whereas the mass and volume power densities of low-pressure hydrogen-and-oxygen-fuel plate-and-frame fuel cells designed to operate in the targeted power range are typically less than 0.1 W/g and 0.1 kW/L, micro-tubular fuel cells are expected to reach power densities much greater than 1 W/g and 1 kW/L. Because of their higher power densities, micro-tubular fuel cells would be better for powering portable equipment, and would be better suited to applications in which there are requirements for modularity to simplify maintenance or to facilitate scaling to higher power levels. The development of PEMFCs has conventionally focused on producing large stacks of cells that operate at typical power levels >5 kW. The usual approach taken to developing lower-power PEMFCs for applications like those listed above has been to simply shrink the basic plate-and-frame configuration to smaller dimensions. A conventional plate-and-frame fuel cell contains a membrane/electrode assembly in the form of a flat membrane with electrodes of the same active area bonded to both faces. In order to provide reactants to both electrodes, bipolar plates that contain flow passages are placed on both electrodes. The mass and volume overhead of the bipolar plates amounts to about 75 percent of the total mass and volume of a fuel-cell stack. Removing these bipolar plates in the micro-tubular fuel cell significantly increases the power density.

  15. Apparatus and method for grounding compressed fuel fueling operator

    DOEpatents

    Cohen, Joseph Perry; Farese, David John; Xu, Jianguo

    2002-06-11

    A safety system for grounding an operator at a fueling station prior to removing a fuel fill nozzle from a fuel tank upon completion of a fuel filling operation is provided which includes a fuel tank port in communication with the fuel tank for receiving and retaining the nozzle during the fuel filling operation and a grounding device adjacent to the fuel tank port which includes a grounding switch having a contact member that receives physical contact by the operator and where physical contact of the contact member activates the grounding switch. A releasable interlock is included that provides a lock position wherein the nozzle is locked into the port upon insertion of the nozzle into the port and a release position wherein the nozzle is releasable from the port upon completion of the fuel filling operation and after physical contact of the contact member is accomplished.

  16. Miniature ceramic fuel cell

    DOEpatents

    Lessing, Paul A.; Zuppero, Anthony C.

    1997-06-24

    A miniature power source assembly capable of providing portable electricity is provided. A preferred embodiment of the power source assembly employing a fuel tank, fuel pump and control, air pump, heat management system, power chamber, power conditioning and power storage. The power chamber utilizes a ceramic fuel cell to produce the electricity. Incoming hydro carbon fuel is automatically reformed within the power chamber. Electrochemical combustion of hydrogen then produces electricity.

  17. Molten carbonate fuel cell

    DOEpatents

    Kaun, Thomas D.; Smith, James L.

    1987-01-01

    A molten electrolyte fuel cell with an array of stacked cells and cell enclosures isolating each cell except for access to gas manifolds for the supply of fuel or oxidant gas or the removal of waste gas, the cell enclosures collectively providing an enclosure for the array and effectively avoiding the problems of electrolyte migration and the previous need for compression of stack components, the fuel cell further including an inner housing about and in cooperation with the array enclosure to provide a manifold system with isolated chambers for the supply and removal of gases. An external insulated housing about the inner housing provides thermal isolation to the cell components.

  18. Molten carbonate fuel cell

    DOEpatents

    Kaun, T.D.; Smith, J.L.

    1986-07-08

    A molten electrolyte fuel cell is disclosed with an array of stacked cells and cell enclosures isolating each cell except for access to gas manifolds for the supply of fuel or oxidant gas or the removal of waste gas. The cell enclosures collectively provide an enclosure for the array and effectively avoid the problems of electrolyte migration and the previous need for compression of stack components. The fuel cell further includes an inner housing about and in cooperation with the array enclosure to provide a manifold system with isolated chambers for the supply and removal of gases. An external insulated housing about the inner housing provides thermal isolation to the cell components.

  19. Fuel cell technology for prototype logistic fuel cell mobile systems

    SciTech Connect

    Sederquist, R.A.; Garow, J.

    1995-08-01

    Under the aegis of the Advanced Research Project Agency`s family of programs to develop advanced technology for dual use applications, International Fuel Cells Corporation (IFC) is conducting a 39 month program to develop an innovative system concept for DoD Mobile Electric Power (MEP) applications. The concept is to integrate two technologies, the phosphoric acid fuel cell (PAFC) with an auto-thermal reformer (ATR), into an efficient fuel cell power plant of nominally 100-kilowatt rating which operates on logistic fuels (JP-8). The ATR fuel processor is the key to meeting requirements for MEP (including weight, volume, reliability, maintainability, efficiency, and especially operation on logistic fuels); most of the effort is devoted to ATR development. An integrated demonstration test unit culminates the program and displays the benefits of the fuel cell system, relative to the standard 100-kilowatt MEP diesel engine generator set. A successful test provides the basis for proceeding toward deployment. This paper describes the results of the first twelve months of activity during which specific program aims have remained firm.

  20. Fuel cell stack monitoring and system control

    DOEpatents

    Keskula, Donald H.; Doan, Tien M.; Clingerman, Bruce J.

    2005-01-25

    A control method for monitoring a fuel cell stack in a fuel cell system in which the actual voltage and actual current from the fuel cell stack are monitored. A preestablished relationship between voltage and current over the operating range of the fuel cell is established. A variance value between the actual measured voltage and the expected voltage magnitude for a given actual measured current is calculated and compared with a predetermined allowable variance. An output is generated if the calculated variance value exceeds the predetermined variance. The predetermined voltage-current for the fuel cell is symbolized as a polarization curve at given operating conditions of the fuel cell. Other polarization curves may be generated and used for fuel cell stack monitoring based on different operating pressures, temperatures, hydrogen quantities.

  1. The TMI regenerable solid oxide fuel cell

    NASA Astrophysics Data System (ADS)

    Cable, Thomas L.

    1995-04-01

    Energy storage and production in space requires rugged, reliable hardware which minimizes weight, volume, and maintenance while maximizing power output and usable energy storage. These systems generally consist of photovoltaic solar arrays which operate during sunlight cycles to provide system power and regenerate fuel (hydrogen) via water electrolysis; during dark cycles, hydrogen is converted by the fuel cell into system. The currently preferred configuration uses two separate systems (fuel cell and electrolyzer) in conjunction with photovoltaic cells. Fuel cell/electrolyzer system simplicity, reliability, and power-to-weight and power-to-volume ratios could be greatly improved if both power production (fuel cell) and power storage (electrolysis) functions can be integrated into a single unit. The Technology Management, Inc. (TMI), solid oxide fuel cell-based system offers the opportunity to both integrate fuel cell and electrolyzer functions into one unit and potentially simplify system requirements. Based an the TMI solid oxide fuel cell (SOPC) technology, the TMI integrated fuel cell/electrolyzer utilizes innovative gas storage and operational concepts and operates like a rechargeable 'hydrogen-oxygen battery'. Preliminary research has been completed on improved H2/H2O electrode (SOFC anode/electrolyzer cathode) materials for solid oxide, regenerative fuel cells. Improved H2/H2O electrode materials showed improved cell performance in both fuel cell and electrolysis modes in reversible cell tests. ln reversible fuel cell/electrolyzer mode, regenerative fuel cell efficiencies (ratio of power out (fuel cell mode) to power in (electrolyzer model)) improved from 50 percent (using conventional electrode materials) to over 80 percent. The new materials will allow the TMI SOFC system to operate as both the electrolyzer and fuel cell in a single unit. Preliminary system designs have also been developed which indicate the technical feasibility of using the TMI SOFC

  2. The TMI regenerable solid oxide fuel cell

    NASA Technical Reports Server (NTRS)

    Cable, Thomas L.

    1995-01-01

    Energy storage and production in space requires rugged, reliable hardware which minimizes weight, volume, and maintenance while maximizing power output and usable energy storage. These systems generally consist of photovoltaic solar arrays which operate during sunlight cycles to provide system power and regenerate fuel (hydrogen) via water electrolysis; during dark cycles, hydrogen is converted by the fuel cell into system. The currently preferred configuration uses two separate systems (fuel cell and electrolyzer) in conjunction with photovoltaic cells. Fuel cell/electrolyzer system simplicity, reliability, and power-to-weight and power-to-volume ratios could be greatly improved if both power production (fuel cell) and power storage (electrolysis) functions can be integrated into a single unit. The Technology Management, Inc. (TMI), solid oxide fuel cell-based system offers the opportunity to both integrate fuel cell and electrolyzer functions into one unit and potentially simplify system requirements. Based an the TMI solid oxide fuel cell (SOPC) technology, the TMI integrated fuel cell/electrolyzer utilizes innovative gas storage and operational concepts and operates like a rechargeable 'hydrogen-oxygen battery'. Preliminary research has been completed on improved H2/H2O electrode (SOFC anode/electrolyzer cathode) materials for solid oxide, regenerative fuel cells. Improved H2/H2O electrode materials showed improved cell performance in both fuel cell and electrolysis modes in reversible cell tests. ln reversible fuel cell/electrolyzer mode, regenerative fuel cell efficiencies (ratio of power out (fuel cell mode) to power in (electrolyzer model)) improved from 50 percent (using conventional electrode materials) to over 80 percent. The new materials will allow the TMI SOFC system to operate as both the electrolyzer and fuel cell in a single unit. Preliminary system designs have also been developed which indicate the technical feasibility of using the TMI SOFC

  3. Nanofluidic fuel cell

    NASA Astrophysics Data System (ADS)

    Lee, Jin Wook; Kjeang, Erik

    2013-11-01

    Fuel cells are gaining momentum as a critical component in the renewable energy mix for stationary, transportation, and portable power applications. State-of-the-art fuel cell technology benefits greatly from nanotechnology applied to nanostructured membranes, catalysts, and electrodes. However, the potential of utilizing nanofluidics for fuel cells has not yet been explored, despite the significant opportunity of harnessing rapid nanoscale reactant transport in close proximity to the reactive sites. In the present article, a nanofluidic fuel cell that utilizes fluid flow through nanoporous media is conceptualized and demonstrated for the first time. This transformative concept captures the advantages of recently developed membraneless and catalyst-free fuel cell architectures paired with the enhanced interfacial contact area enabled by nanofluidics. When compared to previously reported microfluidic fuel cells, the prototype nanofluidic fuel cell demonstrates increased surface area, reduced activation overpotential, superior kinetic characteristics, and moderately enhanced fuel cell performance in the high cell voltage regime with up to 14% higher power density. However, the expected mass transport benefits in the high current density regime were constrained by high ohmic cell resistance, which could likely be resolved through future optimization studies.

  4. Annular feed air breathing fuel cell stack

    DOEpatents

    Wilson, Mahlon S.

    1996-01-01

    A stack of polymer electrolyte fuel cells is formed from a plurality of unit cells where each unit cell includes fuel cell components defining a periphery and distributed along a common axis, where the fuel cell components include a polymer electrolyte membrane, an anode and a cathode contacting opposite sides of the membrane, and fuel and oxygen flow fields contacting the anode and the cathode, respectively, wherein the components define an annular region therethrough along the axis. A fuel distribution manifold within the annular region is connected to deliver fuel to the fuel flow field in each of the unit cells. In a particular embodiment, a single bolt through the annular region clamps the unit cells together. In another embodiment, separator plates between individual unit cells have an extended radial dimension to function as cooling fins for maintaining the operating temperature of the fuel cell stack.

  5. Operation of the 25kW NASA Lewis Research Center Solar Regenerative Fuel Cell Tested Facility

    NASA Technical Reports Server (NTRS)

    Moore, S. H.; Voecks, G. E.

    1997-01-01

    Assembly of the NASA Lewis Research Center(LeRC)Solar Regenerative Fuel Cell (RFC) Testbed Facility has been completed and system testing has proceeded. This facility includes the integration of two 25kW photovoltaic solar cell arrays, a 25kW proton exchange membrane (PEM) electrolysis unit, four 5kW PEM fuel cells, high pressure hydrogen and oxygen storage vessels, high purity water storage containers, and computer monitoring, control and data acquisition.

  6. Operation of the 25kW NASA Lewis Research Center Solar Regenerative Fuel Cell Tested Facility

    NASA Technical Reports Server (NTRS)

    Moore, S. H.; Voecks, G. E.

    1997-01-01

    Assembly of the NASA Lewis Research Center(LeRC)Solar Regenerative Fuel Cell (RFC) Testbed Facility has been completed and system testing has proceeded. This facility includes the integration of two 25kW photovoltaic solar cell arrays, a 25kW proton exchange membrane (PEM) electrolysis unit, four 5kW PEM fuel cells, high pressure hydrogen and oxygen storage vessels, high purity water storage containers, and computer monitoring, control and data acquisition.

  7. Solid oxide fuel cell generator

    DOEpatents

    Di Croce, A. Michael; Draper, Robert

    1993-11-02

    A solid oxide fuel cell generator has a plenum containing at least two rows of spaced apart, annular, axially elongated fuel cells. An electrical conductor extending between adjacent rows of fuel cells connects the fuel cells of one row in parallel with each other and in series with the fuel cells of the adjacent row.

  8. Energy: Reimagine Fuel Cells

    SciTech Connect

    Lemmon, John P.

    2015-09-24

    New types of fuel cell on the horizon could eliminate the need for such trade-offs and ease the integration of renewables into the grid. Currently, fuel cells are used to generate only electricity and heat. They can be modified to store energy and produce liquid fuels such as methanol, thanks to breakthroughs in materials and designs. Developing fuel cells with a battery mode is one focus of the programme I direct at the US Advanced Research Projects Agency–Energy (ARPA-E). I lead 13 projects across academia, industry and national laboratories.

  9. Performance comparison of long and short-side chain perfluorosulfonic membranes for high temperature polymer electrolyte membrane fuel cell operation

    NASA Astrophysics Data System (ADS)

    Stassi, A.; Gatto, I.; Passalacqua, E.; Antonucci, V.; Arico, A. S.; Merlo, L.; Oldani, C.; Pagano, E.

    A new Aquivion™ E79-03S short-side chain perfluorosulfonic membrane with a thickness of 30 μm (dry form) and an equivalent weight (EW) of 790 g/equiv recently developed by Solvay-Solexis for high-temperature operation was tested in a pressurised (3 bar abs.) polymer electrolyte membrane (PEM) single cell at a temperature of 130 °C. For comparison, a standard Nafion™ membrane (EW 1100 g/equiv) of similar thickness (50 μm) was investigated under similar operating conditions. Both membranes were tested for high temperature operation in conjunction with an in-house prepared carbon supported Pt electrocatalyst. The electrocatalyst consisted of nanosized Pt particles (particle size ∼2 nm) dispersed on a high surface area carbon black. The electrochemical tests showed better performance for the Aquivion™ membrane as compared to Nafion™ with promising properties for high temperature PEM fuel cell applications. Beside the higher open circuit voltage and lower ohmic constraints, a higher electrocatalytic activity was observed at high temperature for the electrocatalyst-Aquivion™ ionomer interface indicating a better catalyst utilization.

  10. Liquid fuel cells.

    PubMed

    Soloveichik, Grigorii L

    2014-01-01

    The advantages of liquid fuel cells (LFCs) over conventional hydrogen-oxygen fuel cells include a higher theoretical energy density and efficiency, a more convenient handling of the streams, and enhanced safety. This review focuses on the use of different types of organic fuels as an anode material for LFCs. An overview of the current state of the art and recent trends in the development of LFC and the challenges of their practical implementation are presented.

  11. Liquid fuel cells

    PubMed Central

    2014-01-01

    Summary The advantages of liquid fuel cells (LFCs) over conventional hydrogen–oxygen fuel cells include a higher theoretical energy density and efficiency, a more convenient handling of the streams, and enhanced safety. This review focuses on the use of different types of organic fuels as an anode material for LFCs. An overview of the current state of the art and recent trends in the development of LFC and the challenges of their practical implementation are presented. PMID:25247123

  12. Fuel Cells Vehicle Systems Analysis (Fuel Cell Freeze Investigation)

    SciTech Connect

    Pesaran, A.; Kim, G.; Markel, T.; Wipke, K.

    2005-05-01

    Presentation on Fuel Cells Vehicle Systems Analysis (Fuel Cell Freeze Investigation) for the 2005 Hydrogen, Fuel Cells & Infrastructure Technologies Program Annual Review held in Arlington, Virginia on May 23-26, 2005.

  13. Optimum Operation Condition on Distributed Power Supply System with Micro Gas Turbine/Solid Oxide Fuel Cell

    NASA Astrophysics Data System (ADS)

    Suzuki, Hiroshi; Yamada, Miki; Usui, Hiromoto; Komoda, Yoshiyuki

    In order to find the optimum operation condition of a distributed power supply system of 30kW class micro gas turbine (MGT) and solid oxide fuel cell (SOFC) hybrid system with the combination of line electric power and supplied gas, a system analysis has been performed. In this study, an absorption chiller and a boiler were mounted to utilize the exhausted heat from the MGT/SOFC system. The time variation of energy consumption in 24 hours for house and market models was taken into consideration for the calculation of the energy saving ratio of the present system. The operation ratio defined with the ratio of power supply of MGT/SOFC system to the power required at the peak load was changed as a parameter. From the comparison with the system using line power and gas, it is found that the present system shows high energy saving ratio around 0.4 of the operation ratio, but the energy saving ratio severely decreases in the range of high operation ratio. In this study, it is revealed that the thermal storage system effectively improves the energy saving ratio especially for the house model in winter season.

  14. CLIMATE CHANGE FUEL CELL PROGRAM

    SciTech Connect

    Mike Walneuski

    2004-09-16

    ChevronTexaco has successfully operated a 200 kW PC25C phosphoric acid fuel cell power plant at the corporate data center in San Ramon, California for the past two years and seven months following installation in December 2001. This site was chosen based on the ability to utilize the combined heat (hot water) and power generation capability of this modular fuel cell power plant in an office park setting . In addition, this project also represents one of the first commercial applications of a stationary fuel cell for a mission critical data center to assess power reliability benefits. This fuel cell power plant system has demonstrated outstanding reliability and performance relative to other comparably sized cogeneration systems.

  15. Novel membranes for proton exchange membrane fuel cell operation above 120°C. Final report for period October 1, 1998 to December 31, 1999

    SciTech Connect

    Srinivasan, Supramaniam; Lee, Seung-Jae; Costamagna, Paola; Yang, Christopher; Adjemian, Kevork; Bocarsly, Andrew; Ogden, Joan M.; Benziger, Jay

    2000-05-01

    In this project we investigated the experimental performance of three new classes of membranes, composites of perfluorosulfonic acid polymers with heteropolyacides, hydrated oxides and fast proton conducting glasses, which are promising candidates as electrolytes for proton exchange membrane fuel cells (PEMFCs), capable of operation at temperatures above 120°C. The motivations for PEMFC's operation at this temperature are to: 1) minimize the CO poisoning problem (adsorption of CO onto the platinum catalyst is greatly reduced at these temperatures), 2) find better solutions for the water and thermal management problems in proton exchange membrane fuel cells, 3) find potentially lower cost materials for proton exchange membranes. We prepared and characterized a variety of novel membrane materials. The most promising of these have been evaluated for performance in a single, small area (5cm2) fuel cell run on hydrogen and oxygen. Our results establish the technical feasibility of PEMFC operation above 120°C.

  16. Hybrid cars now, fuel cell cars later.

    PubMed

    Demirdöven, Nurettin; Deutch, John

    2004-08-13

    We compare the energy efficiency of hybrid and fuel cell vehicles as well as conventional internal combustion engines. Our analysis indicates that fuel cell vehicles using hydrogen from fossil fuels offer no significant energy efficiency advantage over hybrid vehicles operating in an urban drive cycle. We conclude that priority should be placed on hybrid vehicles by industry and government.

  17. Hybrid Cars Now, Fuel Cell Cars Later

    NASA Astrophysics Data System (ADS)

    Demirdöven, Nurettin; Deutch, John

    2004-08-01

    We compare the energy efficiency of hybrid and fuel cell vehicles as well as conventional internal combustion engines. Our analysis indicates that fuel cell vehicles using hydrogen from fossil fuels offer no significant energy efficiency advantage over hybrid vehicles operating in an urban drive cycle. We conclude that priority should be placed on hybrid vehicles by industry and government.

  18. General Motors automotive fuel cell program

    SciTech Connect

    Fronk, M.H.

    1995-08-01

    The objectives of the second phase of the GM/DOE fuel cell program is to develop and test a 30 kW fuel cell powerplant. This powerplant will be based on a methanol fuel processor and a proton exchange membrane PM fuel cell stack. In addition, the 10 kW system developed during phase I will be used as a {open_quotes}mule{close_quotes} to test automotive components and other ancillaries, needed for transient operation.

  19. Tilted fuel cell apparatus

    DOEpatents

    Cooper, John F.; Cherepy, Nerine; Krueger, Roger L.

    2005-04-12

    Bipolar, tilted embodiments of high temperature, molten electrolyte electrochemical cells capable of directly converting carbon fuel to electrical energy are disclosed herein. The bipolar, tilted configurations minimize the electrical resistance between one cell and others connected in electrical series. The tilted configuration also allows continuous refueling of carbon fuel.

  20. PLATINUM AND FUEL CELLS

    EPA Science Inventory

    Platinum requirements for fuel cell vehicles (FCVS) have been identified as a concern and possible problem with FCV market penetration. Platinum is a necessary component of the electrodes of fuel cell engines that power the vehicles. The platinum is deposited on porous electrodes...

  1. CEROLYTE FUEL CELL.

    DTIC Science & Technology

    construction of a power plant for space. A 50-watt cerolyte battery will be constructed and a 500-watt fuel - cell power plant will be designed. Research...evaluation of a 500-watt cerolyte fuel - cell power system for space. During the first quarter work has been concentrated in the first two areas.

  2. Fuel Cells for Society

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Through a SBIR contract with Lewis Research Center, ElectroChem, Inc. developed a hydrogen/oxygen fuel cell. The objective for Lewis Research Center's collaboration with ElectroChem was to develop a fuel cell system that could deliver 200-W (minimum) approximately to 10kWh of electrical energy.

  3. PLATINUM AND FUEL CELLS

    EPA Science Inventory

    Platinum requirements for fuel cell vehicles (FCVS) have been identified as a concern and possible problem with FCV market penetration. Platinum is a necessary component of the electrodes of fuel cell engines that power the vehicles. The platinum is deposited on porous electrodes...

  4. Regenerative fuel cells

    NASA Technical Reports Server (NTRS)

    Swette, Larry L.; Kackley, Nancy D.; Laconti, Anthony B.

    1992-01-01

    A development status evaluation is presented for moderate-temperature, single-unit, regenerative fuel cells using either alkaline or solid polymer proton-exchange membrane (PEM) electrolytes. Attention is given to the results thus far obtained for Pt, Ir, Rh, and Na(x)Pt3O4 catalysts. Alkaline electrolyte tests have been performed on a half-cell basis with a floating-electrode cell; PEM testing has been with complete fuel cells, using Nafion 117.

  5. Regenerative fuel cells

    NASA Astrophysics Data System (ADS)

    Swette, Larry L.; Kackley, Nancy D.; Laconti, Anthony B.

    A development status evaluation is presented for moderate-temperature, single-unit, regenerative fuel cells using either alkaline or solid polymer proton-exchange membrane (PEM) electrolytes. Attention is given to the results thus far obtained for Pt, Ir, Rh, and Na(x)Pt3O4 catalysts. Alkaline electrolyte tests have been performed on a half-cell basis with a floating-electrode cell; PEM testing has been with complete fuel cells, using Nafion 117.

  6. Mass balance research for high electrochemical performance direct methanol fuel cells with reduced methanol crossover at various operating conditions

    NASA Astrophysics Data System (ADS)

    Park, Jun-Young; Lee, Jin-Hwa; Kang, SangKyun; Sauk, Jun-Ho; Song, Inseob

    Mass balance research in direct methanol fuel cells (DMFCs) provides a more practical method in characterizing the mass transport phenomena in a membrane electrode assembly (MEA). This method can be used to measure methanol utilization efficiency, water transport coefficient (WTC), and methanol to electricity conversion rate of a MEA in DMFCs. First, the vital design parameters of a MEA are recognized for achieving high methanol utilization efficiency with increased power density. In particular, the structural adjustment of anode diffusion layer by adding microporous layer (MPL) is a very effective way to decrease WTC with reduced methanol crossover due to the mass transfer limitation in the anode. On the other hand, the cathode MPL in the MEA design can contribute in decreasing methanol crossover. The change of structure of cathode diffusion layer is also found to be a very effective way in improving power density. In contrast, the WTC of DMFC MEAs remains virtually constant in the range of 3.4 and 3.6 irrespective of the change of the cathode GDL. The influence of operating condition on the methanol utilization efficiency, WTC, and methanol to electricity conversion rate is also presented and it is found that these mass balance properties are strongly affected by temperature, current density, methanol concentration, and the stoichiometry of fuel and air.

  7. Fuel Cell Applied Research Project

    SciTech Connect

    Lee Richardson

    2006-09-15

    Since November 12, 2003, Northern Alberta Institute of Technology has been operating a 200 kW phosphoric acid fuel cell to provide electrical and thermal energy to its campus. The project was made possible by funding from the U.S. Department of Energy as well as by a partnership with the provincial Alberta Energy Research Institute; a private-public partnership, Climate Change Central; the federal Ministry of Western Economic Development; and local natural gas supplier, ATCO Gas. Operation of the fuel cell has contributed to reducing NAIT's carbon dioxide emissions through its efficient use of natural gas.

  8. Effect of fabrication technique on direct methanol fuel cells designed to operate at low airflow

    NASA Technical Reports Server (NTRS)

    Valdez, T. I.; Narayanan, S. R.

    2002-01-01

    This study investigates the effects of catalyst ink constituents and MEA fabrication techniques on improving cell performance. Particular attention was focused on increasing the overall cell efficiency.

  9. Effect of fabrication technique on direct methanol fuel cells designed to operate at low airflow

    NASA Technical Reports Server (NTRS)

    Valdez, T. I.; Narayanan, S. R.

    2002-01-01

    This study investigates the effects of catalyst ink constituents and MEA fabrication techniques on improving cell performance. Particular attention was focused on increasing the overall cell efficiency.

  10. Chemometrical assessment of the electrical parameters obtained by long-term operating freshwater sediment microbial fuel cells.

    PubMed

    Mitov, Mario; Bardarov, Ivo; Mandjukov, Petko; Hubenova, Yolina

    2015-12-01

    The electrical parameters of nine freshwater sediment microbial fuel cells (SMFCs) were monitored for a period of over 20 months. The developed SMFCs, divided into three groups, were started up and continuously operated under different constant loads (100, 510 and 1100 Ω) for 2.5 months. At this stage of the experiment, the highest power density values, reaching 1.2 ± 0.2 mW/m(2), were achieved by the SMFCs loaded with 510 Ω. The maximum power obtained at periodical polarization during the rest period, however, ranged between 26.2 ± 2.8 and 35.3 ± 2.8 mW/m(2), strongly depending on the internal cell resistance. The statistical evaluation of data derived from the polarization curves shows that after 300 days of operation all examined SMFCs reached a steady-state and the system might be assumed as homoscedastic. The estimated values of standard and expanded uncertainties of the electric parameters indicate a high repeatability and reproducibility of the SMFCs' performance. Results obtained in subsequent discharge-recovery cycles reveal the opportunity for practical application of studied SMFCs as autonomous power sources.

  11. Fuel cell water transport

    DOEpatents

    Vanderborgh, Nicholas E.; Hedstrom, James C.

    1990-01-01

    The moisture content and temperature of hydrogen and oxygen gases is regulated throughout traverse of the gases in a fuel cell incorporating a solid polymer membrane. At least one of the gases traverses a first flow field adjacent the solid polymer membrane, where chemical reactions occur to generate an electrical current. A second flow field is located sequential with the first flow field and incorporates a membrane for effective water transport. A control fluid is then circulated adjacent the second membrane on the face opposite the fuel cell gas wherein moisture is either transported from the control fluid to humidify a fuel gas, e.g., hydrogen, or to the control fluid to prevent excess water buildup in the oxidizer gas, e.g., oxygen. Evaporation of water into the control gas and the control gas temperature act to control the fuel cell gas temperatures throughout the traverse of the fuel cell by the gases.

  12. Direct methanol fuel cell for portable applications

    SciTech Connect

    Valdez, T.I.; Narayanan, S.R.; Frank, H.; Chun, W.

    1997-12-01

    A five cell direct methanol fuel cell stack has been developed at the Jet Propulsion Laboratory. Presently direct methanol fuel cell technology is being incorporated into a system for portable applications. Electrochemical performance and its dependence on flow rate and temperature for a five cell stack are presented. Water transport data, and water transport mechanisms for direct methanol fuel cells are discussed. Stack response to pulse loads has been characterized. Implications of stack performance and operating conditions on system design have been addressed.

  13. Preventing CO poisoning in fuel cells

    DOEpatents

    Gottesfeld, Shimshon

    1990-01-01

    Proton exchange membrane (PEM) fuel cell performance with CO contamination of the H.sub.2 fuel stream is substantially improved by injecting O.sub.2 into the fuel stream ahead of the fuel cell. It is found that a surface reaction occurs even at PEM operating temperatures below about 100.degree. C. to oxidatively remove the CO and restore electrode surface area for the H.sub.2 reaction to generate current. Using an O.sub.2 injection, a suitable fuel stream for a PEM fuel cell can be formed from a methanol source using conventional reforming processes for producing H.sub.2.

  14. Fuel cell vehicles: Status 2007

    NASA Astrophysics Data System (ADS)

    von Helmolt, Rittmar; Eberle, Ulrich

    Within the framework of this paper, a short motivation for hydrogen as a fuel is provided and recent developments in the field of fuel cell vehicles are described. In particular, the propulsion system and its efficiency, as well as the integration of the hydrogen storage system are discussed. A fuel cell drivetrain poses certain requirements (concerning thermodynamic and engineering issues) on the operating conditions of the tank system. These limitations and their consequences are described. For this purpose, conventional and novel storage concepts will be shortly introduced and evaluated for their automotive viability and their potential impact. Eventually, GM's third generation vehicles (i.e. the HydroGen3) are presented, as well as the recent 4th generation Chevrolet Equinox Fuel Cell SUV. An outlook is given that addresses cost targets and infrastructure needs.

  15. PEM fuel cell monitoring system

    DOEpatents

    Meltser, M.A.; Grot, S.A.

    1998-06-09

    Method and apparatus are disclosed for monitoring the performance of H{sub 2}--O{sub 2} PEM fuel cells. Outputs from a cell/stack voltage monitor and a cathode exhaust gas H{sub 2} sensor are corrected for stack operating conditions, and then compared to predetermined levels of acceptability. If certain unacceptable conditions coexist, an operator is alerted and/or corrective measures are automatically undertaken. 2 figs.

  16. PEM fuel cell monitoring system

    DOEpatents

    Meltser, Mark Alexander; Grot, Stephen Andreas

    1998-01-01

    Method and apparatus for monitoring the performance of H.sub.2 --O.sub.2 PEM fuel cells. Outputs from a cell/stack voltage monitor and a cathode exhaust gas H.sub.2 sensor are corrected for stack operating conditions, and then compared to predetermined levels of acceptability. If certain unacceptable conditions coexist, an operator is alerted and/or corrective measures are automatically undertaken.

  17. Internet Fuel Cells Forum

    SciTech Connect

    Sudhoff, Frederick A.

    1996-08-01

    The rapid development and integration of the Internet into the mainstream of professional life provides the fuel cell industry with the opportunity to share new ideas with unprecedented capabilities. The U.S. Department of Energy's (DOE's) Morgantown Energy Technology Center (METC) has undertaken the task to maintain a Fuel Cell Forum on the Internet. Here, members can exchange ideas and information pertaining to fuel cell technologies. The purpose of this forum is to promote a better understanding of fuel cell concepts, terminology, processes, and issues relating to commercialization of fuel cell power technology. The Forum was developed by METC to provide those interested with fuel cell conference information for its current concept of exchanging ideas and information pertaining to fuel cells. Last August, the Forum expanded to an on-line and world-wide network. There are 250 members, and membership is growing at a rate of several new subscribers per week. The forum currently provides updated conference information and interactive information exchange. Forum membership is encouraged from utilities, industry, universities, and government. Because of the public nature of the internet, business sensitive, confidential, or proprietary information should not be placed on this system. The Forum is unmoderated; therefore, the views and opinions of authors expressed in the forum do not necessarily state or reflect those of the U.S. government or METC.

  18. Fuel cells: principles, types, fuels, and applications.

    PubMed

    Carrette, L; Friedrich, K A; Stimming, U

    2000-12-15

    During the last decade, fuel cells have received enormous attention from research institutions and companies as novel electrical energy conversion systems. In the near future, they will see application in automotive propulsion, distributed power generation, and in low power portable devices (battery replacement). This review gives an introduction into the fundamentals and applications of fuel cells: Firstly, the environmental and social factors promoting fuel cell development are discussed, with an emphasis on the advantages of fuel cells compared to the conventional techniques. Then, the main reactions, which are responsible for the conversion of chemical into electrical energy in fuel cells, are given and the thermodynamic and kinetic fundamentals are stated. The theoretical and real efficiencies of fuel cells are also compared to that of internal combustion engines. Next, the different types of fuel cells and their main components are explained and the related material issues are presented. A section is devoted to fuel generation and storage, which is of paramount importance for the practical aspects of fuel cell use. Finally, attention is given to the integration of the fuel cells into complete systems. © 2000 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.

  19. Fuel quality issues in stationary fuel cell systems.

    SciTech Connect

    Papadias, D.; Ahmed, S.; Kumar, R.

    2012-02-07

    Fuel cell systems are being deployed in stationary applications for the generation of electricity, heat, and hydrogen. These systems use a variety of fuel cell types, ranging from the low temperature polymer electrolyte fuel cell (PEFC) to the high temperature solid oxide fuel cell (SOFC). Depending on the application and location, these systems are being designed to operate on reformate or syngas produced from various fuels that include natural gas, biogas, coal gas, etc. All of these fuels contain species that can potentially damage the fuel cell anode or other unit operations and processes that precede the fuel cell stack. These detrimental effects include loss in performance or durability, and attenuating these effects requires additional components to reduce the impurity concentrations to tolerable levels, if not eliminate the impurity entirely. These impurity management components increase the complexity of the fuel cell system, and they add to the system's capital and operating costs (such as regeneration, replacement and disposal of spent material and maintenance). This project reviewed the public domain information available on the impurities encountered in stationary fuel cell systems, and the effects of the impurities on the fuel cells. A database has been set up that classifies the impurities, especially in renewable fuels, such as landfill gas and anaerobic digester gas. It documents the known deleterious effects on fuel cells, and the maximum allowable concentrations of select impurities suggested by manufacturers and researchers. The literature review helped to identify the impurity removal strategies that are available, and their effectiveness, capacity, and cost. A generic model of a stationary fuel-cell based power plant operating on digester and landfill gas has been developed; it includes a gas processing unit, followed by a fuel cell system. The model includes the key impurity removal steps to enable predictions of impurity breakthrough

  20. Fuel cell generator energy dissipator

    DOEpatents

    Veyo, Stephen Emery; Dederer, Jeffrey Todd; Gordon, John Thomas; Shockling, Larry Anthony

    2000-01-01

    An apparatus and method are disclosed for eliminating the chemical energy of fuel remaining in a fuel cell generator when the electrical power output of the fuel cell generator is terminated. During a generator shut down condition, electrically resistive elements are automatically connected across the fuel cell generator terminals in order to draw current, thereby depleting the fuel

  1. Fuel Cells: Reshaping the Future

    ERIC Educational Resources Information Center

    Toay, Leo

    2004-01-01

    In conjunction with the FreedomCAR (Cooperative Automotive Research) and Fuel Initiative, President George W. Bush has pledged nearly two billion dollars for fuel cell research. Chrysler, Ford, and General Motors have unveiled fuel cell demonstration vehicles, and all three of these companies have invested heavily in fuel cell research. Fuel cell…

  2. Fuel Cells: Reshaping the Future

    ERIC Educational Resources Information Center

    Toay, Leo

    2004-01-01

    In conjunction with the FreedomCAR (Cooperative Automotive Research) and Fuel Initiative, President George W. Bush has pledged nearly two billion dollars for fuel cell research. Chrysler, Ford, and General Motors have unveiled fuel cell demonstration vehicles, and all three of these companies have invested heavily in fuel cell research. Fuel cell…

  3. Bipolar fuel cell

    DOEpatents

    McElroy, James F.

    1989-01-01

    The present invention discloses an improved fuel cell utilizing an ion transporting membrane having a catalytic anode and a catalytic cathode bonded to opposite sides of the membrane, a wet-proofed carbon sheet in contact with the cathode surface opposite that bonded to the membrane and a bipolar separator positioned in electrical contact with the carbon sheet and the anode of the adjacent fuel cell. Said bipolar separator and carbon sheet forming an oxidant flowpath, wherein the improvement comprises an electrically conductive screen between and in contact with the wet-proofed carbon sheet and the bipolar separator improving the product water removal system of the fuel cell.

  4. Carbonate fuel cell power plant systems

    NASA Astrophysics Data System (ADS)

    Reinstrom, R. M.

    1981-12-01

    Carbonate fuel cells are an attractive means of developing highly efficient power plants capable of achieving low atmospheric emissions. Because carbonate fuel cells can be used with coal derived fuel gases and their operating temperatures allow the use of turbomachinery bottoming cycles, they are well suited for large installations like central utility stations. Presently, system development activity is directed toward evaluating the readiness of gasifier and fuel processor technology, defining candidate cycle configurations, and calculating projected plant efficiencies.

  5. Investigation of the flow field inside the manifold of a real operated fuel cell stack using optical measurements and Computational Fluid Mechanics

    NASA Astrophysics Data System (ADS)

    Schmieder, Felix; Kinaci, Mustafa E.; Wartmann, Jens; König, Jörg; Büttner, Lars; Czarske, Jürgen; Burgmann, Sebastian; Heinzel, Angelika

    2016-02-01

    The versatility of fuel cells enables a wide range of applications. Usually fuel cells are combined to stacks such that the reactant supply of the single cells is achieved via a pipe branching system, the manifold. The overall performance significantly depends on cell flow rates which are related to the fluidic interaction of the manifold and the cells. Computational Fluid Dynamics (CFD) simulations, which are often used to find a suitable design, lack experimental flow data for validation of the numerical results. To enable flow measurements within the small geometries of the manifold and to provide reliable velocity information inside a real fuel cell stack, a low-coherence Laser Doppler Anemometer (LDA) is applied, which uses multi-mode laser light to achieve a spatial resolution of <100 μm. The use of fluorescent particles and backward scatter mode make the sensor highly suitable for the application in small manifold geometries like in fuel cell stacks. Sensor and measurement technique are validated in simplified stack models and the applicability to air flows is demonstrated. Finally, for the first time, velocity profiles with high spatial resolution inside an operated fuel cell stack are presented, which serve as benchmark for CFD to find an optimal geometry.

  6. Anode purge strategy optimization of the polymer electrode membrane fuel cell system under the dead-end anode operation

    NASA Astrophysics Data System (ADS)

    Hu, Zhe; Yu, Yi; Wang, Guangjin; Chen, Xuesong; Chen, Pei; Chen, Jun; Zhou, Su

    2016-07-01

    Dead-ended anode (DEA) mode is commonly applied in fuel cell vehicles for the hydrogen purge at the anode side, to reduce fuel waste and enhance fuel cell efficiency. Anode purge is necessary and is definitely important with respect to removing liquid water and accumulated nitrogen in the gas diffusion layer and the flow field of the DEA-mode fuel cell. In this paper, the effect of different purge strategies on the stack performance and system efficiency is investigated experimentally using fast data acquisition and advanced tools, such as the fast cell voltage measurement (CVM) system and the mass spectrum. From the fast data acquisition, the voltage stability, liquid water and nitrogen concentration measurement in the anode exhaust are compared and analyzed under different purge strategy designs and using different purge valves. The results show that under the optimal purge strategy, the DEA fuel cell stack can achieve the desired stability and system efficiency based on the analysis of the cell voltage and purge volume. Moreover, the diameter of the purge valve has a great impact on the voltage stability because a diameter change will result in a different pressure drop and purge volume when the purge valve is open.

  7. Fuel cell power supply with oxidant and fuel gas switching

    DOEpatents

    McElroy, J.F.; Chludzinski, P.J.; Dantowitz, P.

    1987-04-14

    This invention relates to a fuel cell vehicular power plant. Fuel for the fuel stack is supplied by a hydrocarbon (methanol) catalytic cracking reactor and CO shift reactor. A water electrolysis subsystem is associated with the stack. During low power operation part of the fuel cell power is used to electrolyze water with hydrogen and oxygen electrolysis products being stored in pressure vessels. During peak power intervals, viz, during acceleration or start-up, pure oxygen and pure hydrogen from the pressure vessel are supplied as the reaction gases to the cathodes and anodes in place of air and methanol reformate. This allows the fuel cell stack to be sized for normal low power/air operation but with a peak power capacity several times greater than that for normal operation. 2 figs.

  8. Fuel cell power supply with oxidant and fuel gas switching

    DOEpatents

    McElroy, James F.; Chludzinski, Paul J.; Dantowitz, Philip

    1987-01-01

    This invention relates to a fuel cell vehicular power plant. Fuel for the fuel stack is supplied by a hydrocarbon (methanol) catalytic cracking reactor and CO shift reactor. A water electrolysis subsystem is associated with the stack. During low power operation part of the fuel cell power is used to electrolyze water with hydrogen and oxygen electrolysis products being stored in pressure vessels. During peak power intervals, viz, during acceleration or start-up, pure oxygen and pure hydrogen from the pressure vessel are supplied as the reaction gases to the cathodes and anodes in place of air and methanol reformate. This allows the fuel cell stack to be sized for normal low power/air operation but with a peak power capacity several times greater than that for normal operation.

  9. Three-dimensional microstructural changes in the Ni–YSZ solid oxide fuel cell anode during operation

    SciTech Connect

    Nelson G. J.; Chu Y.; Grew, K.N.; Izzo Jr. J.R.; Lombardo, J.J.; Harris, W.M.; Faes, A.; Hessler-Wyser, A.; Van herle, J.; Wang, S.; Virkar, A.V.; Chiu, W.K.S.

    2012-04-07

    Microstructural evolution in solid oxide fuel cell (SOFC) cermet anodes has been investigated using X-ray nanotomography along with differential absorption imaging. SOFC anode supports composed of Ni and yttria-stabilized zirconia (YSZ) were subjected to extended operation and selected regions were imaged using a transmission X-ray microscope. X-ray nanotomography provides unique insight into microstructure changes of all three phases (Ni, YSZ, pore) in three spatial dimensions, and its relation to performance degradation. Statistically significant 3D microstructural changes were observed in the anode Ni phase over a range of operational times, including phase size growth and changes in connectivity, interfacial contact area and contiguous triple-phase boundary length. These observations support microstructural evolution correlated to SOFC performance. We find that Ni coarsening is driven by particle curvature as indicated by the dihedral angles between the Ni, YSZ and pore phases, and hypothesize that growth occurs primarily by means of diffusion and particle agglomeration constrained by a pinning mechanism related to the YSZ phase. The decrease in Ni phase size after extended periods of time may be the result of a second process connected to a mobility-induced decrease in the YSZ phase size or non-uniform curvature resulting in a net decrease in Ni phase size.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Stabilizing platinum in phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Remick, R. J.

    1982-01-01

    Platinum sintering on phosphoric acid fuel cell cathodes is discussed. The cathode of the phosphoric acid fuel cell uses a high surface area platinum catalyst dispersed on a conductive carbon support to minimize both cathode polarization and fabrication costs. During operation, however, the active surface area of these electrodes decreases, which in turn leads to decreased cell performance. This loss of active surface area is a major factor in the degradation of fuel cell performance over time.

  12. Fuel processor for fuel cell power system

    DOEpatents

    Vanderborgh, Nicholas E.; Springer, Thomas E.; Huff, James R.

    1987-01-01

    A catalytic organic fuel processing apparatus, which can be used in a fuel cell power system, contains within a housing a catalyst chamber, a variable speed fan, and a combustion chamber. Vaporized organic fuel is circulated by the fan past the combustion chamber with which it is in indirect heat exchange relationship. The heated vaporized organic fuel enters a catalyst bed where it is converted into a desired product such as hydrogen needed to power the fuel cell. During periods of high demand, air is injected upstream of the combustion chamber and organic fuel injection means to burn with some of the organic fuel on the outside of the combustion chamber, and thus be in direct heat exchange relation with the organic fuel going into the catalyst bed.

  13. Microbial fuel cell treatment of fuel process wastewater

    DOEpatents

    Borole, Abhijeet P; Tsouris, Constantino

    2013-12-03

    The present invention is directed to a method for cleansing fuel processing effluent containing carbonaceous compounds and inorganic salts, the method comprising contacting the fuel processing effluent with an anode of a microbial fuel ell, the anode containing microbes thereon which oxidatively degrade one or more of the carbonaceous compounds while producing electrical energy from the oxidative degradation, and directing the produced electrical energy to drive an electrosorption mechanism that operates to reduce the concentration of one or more inorganic salts in the fuel processing effluent, wherein the anode is in electrical communication with a cathode of the microbial fuel cell. The invention is also directed to an apparatus for practicing the method.

  14. Fuel Cell Animation

    NASA Image and Video Library

    Oxygen (O2) and hydrogen (H2) migrate into the fuel cell. The oxygen molecules migrate to the catalyst where the anode strips some of their electrons. This allows them to move through the cathode a...

  15. Controlled shutdown of a fuel cell

    DOEpatents

    Clingerman, Bruce J.; Keskula, Donald H.

    2002-01-01

    A method is provided for the shutdown of a fuel cell system to relieve system overpressure while maintaining air compressor operation, and corresponding vent valving and control arrangement. The method and venting arrangement are employed in a fuel cell system, for instance a vehicle propulsion system, comprising, in fluid communication, an air compressor having an outlet for providing air to the system, a combustor operative to provide combustor exhaust to the fuel processor.

  16. STAGING OF FUEL CELLS - PHASE II

    SciTech Connect

    Per Onnerud; Suresh Sriramulu

    2002-08-29

    TIAX has executed a laboratory-based development program aiming at the improvement of stationary fuel cell systems. The two-year long development program resulted in an improved understanding of staged fuel cells and inorganic proton conductors through evaluation of results from a number of laboratory tasks: (1) Development of a fuel cell modeling tool--Multi-scale model was developed, capable of analyzing the effects of materials and operating conditions; and this model allowed studying various ''what-if'' conditions for hypothetically staged fuel cells; (2) Study of new high temperature proton conductor--TIAX discovery of a new class of sulfonated inorganics capable of conducting protons when exposed to water; and study involved synthesis and conductivity measurements of novel compounds up to 140 C; (3) Electrochemical fuel cell measurements--the feasibility of staged fuel cells was tested in TIAX's fuel cell laboratories experimental design was based on results from modeling.

  17. Composite fuel cell membranes

    DOEpatents

    Plowman, K.R.; Rehg, T.J.; Davis, L.W.; Carl, W.P.; Cisar, A.J.; Eastland, C.S.

    1997-08-05

    A bilayer or trilayer composite ion exchange membrane is described suitable for use in a fuel cell. The composite membrane has a high equivalent weight thick layer in order to provide sufficient strength and low equivalent weight surface layers for improved electrical performance in a fuel cell. In use, the composite membrane is provided with electrode surface layers. The composite membrane can be composed of a sulfonic fluoropolymer in both core and surface layers.

  18. Compliant fuel cell system

    DOEpatents

    Bourgeois, Richard Scott; Gudlavalleti, Sauri

    2009-12-15

    A fuel cell assembly comprising at least one metallic component, at least one ceramic component and a structure disposed between the metallic component and the ceramic component. The structure is configured to have a lower stiffness compared to at least one of the metallic component and the ceramic component, to accommodate a difference in strain between the metallic component and the ceramic component of the fuel cell assembly.

  19. Composite fuel cell membranes

    DOEpatents

    Plowman, Keith R.; Rehg, Timothy J.; Davis, Larry W.; Carl, William P.; Cisar, Alan J.; Eastland, Charles S.

    1997-01-01

    A bilayer or trilayer composite ion exchange membrane suitable for use in a fuel cell. The composite membrane has a high equivalent weight thick layer in order to provide sufficient strength and low equivalent weight surface layers for improved electrical performance in a fuel cell. In use, the composite membrane is provided with electrode surface layers. The composite membrane can be composed of a sulfonic fluoropolymer in both core and surface layers.

  20. Post-test analysis of 20kW molten carbonate fuel cell stack operated on coal gas. Final report, August 1993--February 1996

    SciTech Connect

    1996-05-01

    A 20kW carbonate fuel cell stack was operated with coal gas for the first time in the world. The stack was tested for a total of 4,000 hours, of which 3,900 hours of testing was conducted at the Louisiana Gasification Technology Incorporated, Plaquemine, Louisiana outdoor site. The operation was on either natural gas or coal gas and switched several times without any effects, demonstrating duel fuel capabilities. This test was conducted with 9142 kJ/m{sup 3} (245 Btu/cft) coal gas provided by a slipstream from Destec`s entrained flow, slagging, slurry-fed gasifier equipped with a cold gas cleanup subsystem. The stack generated up to 21 kW with this coal gas. Following completion of this test, the stack was brought to Energy Research Corporation (ERC) and a detailed post-test analysis was conducted to identify any effects of coal gas on cell components. This investigation has shown that the direct fuel cell (DFC) can be operated with properly cleaned and humidified coal-as, providing stable performance. The basic C direct fuel cell component materials are stable and display normal stability in presence of the coal gas. No effects of the coal-borne contaminants are apparent. Further cell testing at ERC 1 17, confirmed these findings.

  1. 2009 Fuel Cell Market Report

    SciTech Connect

    Vincent, Bill; Gangi, Jennifer; Curtin, Sandra; Delmont, Elizabeth

    2010-11-01

    Fuel cells are electrochemical devices that combine hydrogen and oxygen to produce electricity, water, and heat. Unlike batteries, fuel cells continuously generate electricity, as long as a source of fuel is supplied. Moreover, fuel cells do not burn fuel, making the process quiet, pollution-free and two to three times more efficient than combustion. Fuel cell systems can be a truly zero-emission source of electricity, if the hydrogen is produced from non-polluting sources. Global concerns about climate change, energy security, and air pollution are driving demand for fuel cell technology. More than 630 companies and laboratories in the United States are investing $1 billion a year in fuel cells or fuel cell component technologies. This report provides an overview of trends in the fuel cell industry and markets, including product shipments, market development, and corporate performance. It also provides snapshots of select fuel cell companies, including general.

  2. Internal reforming fuel cell assembly with simplified fuel feed

    DOEpatents

    Farooque, Mohammad; Novacco, Lawrence J.; Allen, Jeffrey P.

    2001-01-01

    A fuel cell assembly in which fuel cells adapted to internally reform fuel and fuel reformers for reforming fuel are arranged in a fuel cell stack. The fuel inlet ports of the fuel cells and the fuel inlet ports and reformed fuel outlet ports of the fuel reformers are arranged on one face of the fuel cell stack. A manifold sealing encloses this face of the stack and a reformer fuel delivery system is arranged entirely within the region between the manifold and the one face of the stack. The fuel reformer has a foil wrapping and a cover member forming with the foil wrapping an enclosed structure.

  3. Dual-radial cell thermionic fuel element

    NASA Astrophysics Data System (ADS)

    Terrell, Charles W.

    A dual-radial cell thermionic fuel element (TFE) has been proposed and partially evaluated. The cell has the capacity to produce considerably more power per gram of fuel than does a single-cell TFE, with a total electrical power in a fast reactor system of several hundred kWs, conservatively operated.

  4. Seventh Edition Fuel Cell Handbook

    SciTech Connect

    NETL

    2004-11-01

    Provides an overview of fuel cell technology and research projects. Discusses the basic workings of fuel cells and their system components, main fuel cell types, their characteristics, and their development status, as well as a discussion of potential fuel cell applications.

  5. Separation of gaseous hydrogen from a water-hydrogen mixture in a fuel cell power system operating in a weightless environment

    NASA Technical Reports Server (NTRS)

    Romanowski, William E. (Inventor); Suljak, George T. (Inventor)

    1989-01-01

    A fuel cell power system for use in a weightless environment, such as in space, includes a device for removing water from a water-hydrogen mixture condensed from the exhaust from the fuel cell power section of the system. Water is removed from the mixture in a centrifugal separator, and is fed into a holding, pressure operated water discharge valve via a Pitot tube. Entrained nondissolved hydrogen is removed from the Pitot tube by a bleed orifice in the Pitot tube before the water reaches the water discharge valve. Water discharged from the valve thus has a substantially reduced hydrogen content.

  6. Rapidly refuelable fuel cell

    DOEpatents

    Joy, Richard W.

    1983-01-01

    This invention is directed to a metal-air fuel cell where the consumable metal anode is movably positioned in the cell and an expandable enclosure, or bladder, is used to press the anode into contact with separating spacers between the cell electrodes. The bladder may be depressurized to allow replacement of the anode when consumed.

  7. SOFC cells and stacks for complex fuels

    SciTech Connect

    Edward M. Sabolsky; Matthew Seabaugh; Katarzyna Sabolsky; Sergio A. Ibanez; Zhimin Zhong

    2007-07-01

    Reformed hydrocarbon and coal (syngas) fuels present an opportunity to integrate solid oxide fuel cells into the existing fuel infrastructure. However, these fuels often contain impurities or additives that may lead to cell degradation through sulfur poisoning or coking. Achieving high performance and sulfur tolerance in SOFCs operating on these fuels would simplify system balance of plant and sequestration of anode tail gas. NexTech Materials, Ltd., has developed a suite of materials and components (cells, seals, interconnects) designed for operation in sulfur-containing syngas fuels. These materials and component technologies have been integrated into an SOFC stack for testing on simulated propane, logistic fuel reformates and coal syngas. Details of the technical approach, cell and stack performance is reported.

  8. A lithotrophic microbial fuel cell operated with pseudomonads-dominated iron-oxidizing bacteria enriched at the anode.

    PubMed

    Nguyen, Thuy Thu; Luong, Tha Thanh Thi; Tran, Phuong Hoang Nguyen; Bui, Ha Thi Viet; Nguyen, Huy Quang; Dinh, Hang Thuy; Kim, Byung Hong; Pham, Hai The

    2015-05-01

    In this study, we attempted to enrich neutrophilic iron bacteria in a microbial fuel cell (MFC)-type reactor in order to develop a lithotrophic MFC system that can utilize ferrous iron as an inorganic electron donor and operate at neutral pHs. Electrical currents were steadily generated at an average level of 0.6 mA (or 0.024 mA cm(-2) of membrane area) in reactors initially inoculated with microbial sources and operated with 20 mM Fe(2+) as the sole electron donor and 10 ohm external resistance; whereas in an uninoculated reactor (the control), the average current level only reached 0.2 mA (or 0.008 mA cm(-2) of membrane area). In an inoculated MFC, the generation of electrical currents was correlated with increases in cell density of bacteria in the anode suspension and coupled with the oxidation of ferrous iron. Cultivation-based and denaturing gradient gel electrophoresis analyses both show the dominance of some Pseudomonas species in the anode communities of the MFCs. Fluorescent in-situ hybridization results revealed significant increases of neutrophilic iron-oxidizing bacteria in the anode community of an inoculated MFC. The results, altogether, prove the successful development of a lithotrophic MFC system with iron bacteria enriched at its anode and suggest a chemolithotrophic anode reaction involving some Pseudomonas species as key players in such a system. The system potentially offers unique applications, such as accelerated bioremediation or on-site biodetection of iron and/or manganese in water samples. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  9. A lithotrophic microbial fuel cell operated with pseudomonads-dominated iron-oxidizing bacteria enriched at the anode

    PubMed Central

    Nguyen, Thuy Thu; Luong, Tha Thanh Thi; Tran, Phuong Hoang Nguyen; Bui, Ha Thi Viet; Nguyen, Huy Quang; Dinh, Hang Thuy; Kim, Byung Hong; Pham, Hai The

    2015-01-01

    In this study, we attempted to enrich neutrophilic iron bacteria in a microbial fuel cell (MFC)-type reactor in order to develop a lithotrophic MFC system that can utilize ferrous iron as an inorganic electron donor and operate at neutral pHs. Electrical currents were steadily generated at an average level of 0.6 mA (or 0.024 mA cm–2 of membrane area) in reactors initially inoculated with microbial sources and operated with 20 mM Fe2+ as the sole electron donor and 10 ohm external resistance; whereas in an uninoculated reactor (the control), the average current level only reached 0.2 mA (or 0.008 mA cm–2 of membrane area). In an inoculated MFC, the generation of electrical currents was correlated with increases in cell density of bacteria in the anode suspension and coupled with the oxidation of ferrous iron. Cultivation-based and denaturing gradient gel electrophoresis analyses both show the dominance of some Pseudomonas species in the anode communities of the MFCs. Fluorescent in-situ hybridization results revealed significant increases of neutrophilic iron-oxidizing bacteria in the anode community of an inoculated MFC. The results, altogether, prove the successful development of a lithotrophic MFC system with iron bacteria enriched at its anode and suggest a chemolithotrophic anode reaction involving some Pseudomonas species as key players in such a system. The system potentially offers unique applications, such as accelerated bioremediation or on-site biodetection of iron and/or manganese in water samples. PMID:25712332

  10. Fuel cell cogeneration

    SciTech Connect

    Wimer, J.G.; Archer, D.

    1995-08-01

    The U.S. Department of Energy`s Morgantown Energy Technology Center (METC) sponsors the research and development of engineered systems which utilize domestic fuel supplies while achieving high standards of efficiency, economy, and environmental performance. Fuel cell systems are among the promising electric power generation systems that METC is currently developing. Buildings account for 36 percent of U.S. primary energy consumption. Cogeneration systems for commercial buildings represent an early market opportunity for fuel cells. Seventeen percent of all commercial buildings are office buildings, and large office buildings are projected to be one of the biggest, fastest-growing sectors in the commercial building cogeneration market. The main objective of this study is to explore the early market opportunity for fuel cells in large office buildings and determine the conditions in which they can compete with alternative systems. Some preliminary results and conclusions are presented, although the study is still in progress.

  11. PEM fuel cell durability studies

    SciTech Connect

    Borup, Rodney L; Davey, John R; Ofstad, Axel B; Xu, Hui

    2008-01-01

    The durability of polymer electrolyte membrane (PEM) fuel cells is a major barrier to the commercialization for stationary and transportation power applications. For transportation applications, the durability target for fuel cell power systems is a 5,000 hour lifespan and able to function over a range of vehicle operating conditions (-40{sup o} to +40{sup o}C). However, durability is difficult to quantify and improve because of the quantity and duration of testing required, and also because the fuel cell stack contains many components, for which the degradation mechanisms, component interactions and effects of operating conditions are not fully understood. These requirements have led to the development of accelerated testing protocols for PEM fuel cells. The need for accelerated testing methodology is exemplified by the times required for standard testing to reach their required targets: automotive 5,000 hrs = {approx} 7 months; stationary systems 40,000 hrs = {approx} 4.6 years. As new materials continue to be developed, the need for relevant accelerated testing increases. In this investigation, we examine the durability of various cell components, examine the effect of transportation operating conditions (potential cycling, variable RH, shut-down/start-up, freeze/thaw) and evaluate durability by accelerated durability protocols. PEM fuel cell durability testing is performed on single cells, with tests being conducted with steady-state conditions and with dynamic conditions using power cycling to simulate a vehicle drive cycle. Component and single-cell characterization during and after testing was conducted to identify changes in material properties and related failure mechanisms. Accelerated-testing experiments were applied to further examine material degradation.

  12. The TMI Regenerative Solid Oxide Fuel Cell

    NASA Technical Reports Server (NTRS)

    Cable, Thomas L.; Ruhl, Robert C.; Petrik, Michael

    1996-01-01

    Energy storage and production in space requires rugged, reliable hardware which minimizes weight, volume, and maintenance while maximizing power output and usable energy storage. Systems generally consist of photovoltaic solar arrays which operate (during sunlight cycles) to provide system power and regenerate fuel (hydrogen) via water electrolysis and (during dark cycles) fuel cells convert hydrogen into electricity. Common configurations use two separate systems (fuel cell and electrolyzer) in conjunction with photovoltaic cells. Reliability, power to weight and power to volume ratios could be greatly improved if both power production (fuel cells) and power storage (electrolysis) functions can be integrated into a single unit. The solid oxide fuel cell (SOFC) based design integrates fuel cell and electrolyzer functions and potentially simplifies system requirements. The integrated fuel cell/electrolyzer design also utilizes innovative gas storage concepts and operates like a rechargeable 'hydrogen-oxygen battery'. Preliminary research has been completed on improved H2/H20 electrode (SOFC anode/electrolyzer cathode) materials for regenerative fuel cells. Tests have shown improved cell performance in both fuel and electrolysis modes in reversible fuel cell tests. Regenerative fuel cell efficiencies, ratio of power out (fuel cell mode) to power in (electrolyzer mode), improved from 50 percent using conventional electrode materials to over 80 percent. The new materials will allow a single SOFC system to operate as both the electolyzer and fuel cell. Preliminary system designs have also been developed to show the technical feasibility of using the design for space applications requiring high energy storage efficiencies and high specific energy. Small space systems also have potential for dual-use, terrestrial applications.

  13. Anode supported single chamber solid oxide fuel cells operating in exhaust gases of thermal engine

    NASA Astrophysics Data System (ADS)

    Briault, Pauline; Rieu, Mathilde; Laucournet, Richard; Morel, Bertrand; Viricelle, Jean-Paul

    2014-12-01

    This project deals with the development and the electrochemical characterization of anode supported single chamber SOFC in a simulated environment of thermal engine exhaust gas. In the present work, a gas mixture representative of exhaust conditions is selected. It is composed of hydrocarbons (HC: propane and propene), oxygen, carbon monoxide, carbon dioxide, hydrogen and water. Only oxygen content is varied leading to different gas mixtures characterized by three ratios R = HC/O2. Concerning the cell components, a cermet made of nickel and an electrolyte material, Ce0.9Gd0.1O1.95 (CGO) is used as anode and two cathode materials, La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) and Pr2NiO4+δ (PNO), are evaluated. The prepared cells are investigated in the various gas mixtures for temperatures ranging from 450 °C to 600 °C. Ni-CGO/CGO/LSCF-CGO cell has delivered a maximum power density of 15 mW cm-2 at 500 °C with R = HC/O2 = 0.21, while lower power densities are obtained for the other ratios, R = 0.44 and R = 0.67. Afterwards, LSCF and PNO cathode materials are compared and LSCF is found to deliver the highest power densities. Finally, by improving the electrolyte microstructure, some cells presenting a maximum power density of 25 mW cm-2 at 550 °C are produced. Moreover, up to 17% of initial HC are eliminated in the gas mixture.

  14. Fuel Cells for Space Science Applications

    NASA Technical Reports Server (NTRS)

    Burke, Kenneth A.

    2003-01-01

    Fuel cell technology has been receiving more attention recently as a possible alternative to the internal combustion engine for our automobile. Improvements in fuel cell designs as well as improvements in lightweight high-pressure gas storage tank technology make fuel cell technology worth a look to see if fuel cells can play a more expanded role in space missions. This study looks at the specific weight density and specific volume density of potential fuel cell systems as an alternative to primary and secondary batteries that have traditionally been used for space missions. This preliminary study indicates that fuel cell systems have the potential for energy densities of greater than 500 W-hr/kg, greater than 500W/kg and greater than 400 W-hr/liter, greater than 200 W/liter. This level of performance makes fuel cells attractive as high-power density, high-energy density sources for space science probes, planetary rovers and other payloads. The power requirements for these space missions are, in general, much lower than the power levels where fuel cells have been used in the past. Adaptation of fuel cells for space science missions will require down-sizing the fuel cell stack and making the fuel cell operate without significant amounts of ancillary equipment.

  15. Maximizing power generation from dark fermentation effluents in microbial fuel cell by selective enrichment of exoelectrogens and optimization of anodic operational parameters.

    PubMed

    Varanasi, Jhansi L; Sinha, Pallavi; Das, Debabrata

    2017-05-01

    To selectively enrich an electrogenic mixed consortium capable of utilizing dark fermentative effluents as substrates in microbial fuel cells and to further enhance the power outputs by optimization of influential anodic operational parameters. A maximum power density of 1.4 W/m(3) was obtained by an enriched mixed electrogenic consortium in microbial fuel cells using acetate as substrate. This was further increased to 5.43 W/m(3) by optimization of influential anodic parameters. By utilizing dark fermentative effluents as substrates, the maximum power densities ranged from 5.2 to 6.2 W/m(3) with an average COD removal efficiency of 75% and a columbic efficiency of 10.6%. A simple strategy is provided for selective enrichment of electrogenic bacteria that can be used in microbial fuel cells for generating power from various dark fermentative effluents.

  16. Thermally regenerative fuel cells

    NASA Astrophysics Data System (ADS)

    Ludwig, F. A.; Kindler, A.; McHardy, J.

    1991-10-01

    The three phase project was undertaken to investigate solventless ionic liquids as possible working fluids for a new type of thermally regenerative fuel cell (TRFC). The heart of the new device, invented at Hughes Aircraft Company in 1983, is an electrochemical concentration cell where acid and base streams react to produce electrical energy. Thermal energy is then used to decompose the resulting salts and regenerate the cell reactants. In principle, a TRFC can be matched to any source of thermal energy simply by selecting working fluids with the appropriate regeneration temperature. However, aqueous working fluids (the focus of previous studies) impose limitations on both the operating temperatures and the achievable energy densities. It was the need to overcome these limitations that prompted the present investigation. Specific aims were to identify possible working fluids for TRFC systems with both low and high regeneration temperatures. A major advantage of our aqueous-fluid TRFC systems has been the ability to use hydrogen electrodes. The low activation and mass transfer losses of these electrodes contribute substantially to overall system efficiency.

  17. Operation of a horizontal subsurface flow constructed wetland--microbial fuel cell treating wastewater under different organic loading rates.

    PubMed

    Villaseñor, J; Capilla, P; Rodrigo, M A; Cañizares, P; Fernández, F J

    2013-11-01

    The aim of the present work is to determine whether a horizontal subsurface flow constructed wetland treating wastewater could act simultaneously as a microbial fuel cell (MFC). Specifically, and as the main variable under study, different organic loading rates were used, and the response of the system was monitored. The installation consisted of a synthetic domestic wastewater-feeding system and a pilot-scale constructed wetland for wastewater treatment, which also included coupled devices necessary to function as an MFC. The wetland worked under continuous operation for 180 d, treating three types of synthetic wastewater with increasing organic loading rates: 13.9 g COD m(-2) d(-1), 31.1 g COD m(-2) d(-1), and 61.1 g COD m(-2) d(-1). The COD removal efficiencies and the cell voltage generation were continuously monitored. The wetland worked simultaneously as an MFC generating electric power. Under low organic loading rates, the wastewater organic matter was completely oxidised in the lower anaerobic compartment, and there were slight aerobic conditions in the upper cathodic compartment, thus causing an electrical current. Under high organic loading rates, the organic matter could not be completely oxidised in the anodic compartment and flowed to the cathodic one, which entered into anaerobic conditions and caused the MFC to stop working. The system developed in this work offered similar cell voltage, power density, and current density values compared with the ones obtained in previous studies using photosynthetic MFCs, sediment-type MFCs, and plant-type MFCs. The light/darkness changes caused voltage fluctuations due to the photosynthetic activity of the macrophytes used (Phragmites australis), which affected the conditions in the cathodic compartment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Conductive polymer layers to limit transfer of fuel reactants to catalysts of fuel cells to reduce reactant crossover

    SciTech Connect

    Stanis, Ronald J.; Lambert, Timothy N.

    2016-12-06

    An apparatus of an aspect includes a fuel cell catalyst layer. The fuel cell catalyst layer is operable to catalyze a reaction involving a fuel reactant. A fuel cell gas diffusion layer is coupled with the fuel cell catalyst layer. The fuel cell gas diffusion layer includes a porous electrically conductive material. The porous electrically conductive material is operable to allow the fuel reactant to transfer through the fuel cell gas diffusion layer to reach the fuel cell catalyst layer. The porous electrically conductive material is also operable to conduct electrons associated with the reaction through the fuel cell gas diffusion layer. An electrically conductive polymer material is coupled with the fuel cell gas diffusion layer. The electrically conductive polymer material is operable to limit transfer of the fuel reactant to the fuel cell catalyst layer.

  19. Evaluation of microbial fuel cell operation using algae as an oxygen supplier: carbon paper cathode vs. carbon brush cathode.

    PubMed

    Kakarla, Ramesh; Min, Booki

    2014-12-01

    Microbial fuel cell (MFC) and its cathode performances were compared with use of carbon fiber brush and plain carbon paper cathode electrodes in algae aeration. The MFC having carbon fiber brush cathode exhibited a voltage of 0.21 ± 0.01 V (1,000 Ω) with a cathode potential of around -0.14 ± 0.01 V in algal aeration, whereas MFC with plain carbon paper cathode resulted in a voltage of 0.06 ± 0.005 V with a cathode potential of -0.39 ± 0.01 V. During polarizations, MFC equipped with carbon fiber brush cathode showed a maximum power density of 30 mW/m(2), whereas the MFC equipped with plain carbon paper showed a power density of 4.6 mW/m(2). In algae aeration, the internal resistance with carbon fiber brush cathode was 804 Ω and with plain carbon paper it was 1,210 Ω. The peak currents of MFC operation with carbon fiber brush and plain carbon paper cathodes were -31 mA and -850 µA, respectively.

  20. Microscale measurements of oxygen concentration across the thickness of diffusion media in operating polymer electrolyte fuel cells

    NASA Astrophysics Data System (ADS)

    Epting, William K.; Litster, Shawn

    2016-02-01

    Although polymer electrolyte fuel cells (PEFCs) offer promise as efficient, low emission power sources, the large amount of platinum catalyst used for the cathode's oxygen reduction (ORR) results in high costs. One approach to using less Pt is to increase the oxygen concentration at the catalyst by reducing the oxygen transport resistances. An important resistance is that of the diffusion media (DM). The DM are highly heterogeneous porous carbon fiber substrates with a graded composition of additives across their thickness. In this work we use an oxygen microsensor with a micro-positioning system to measure the oxygen concentration and presence of liquid water in the pores at discrete points across the thickness of a commercial carbon felt DM in operating PEFCs. Under conditions with no liquid water, the DM accounts for 60% of the oxygen depletion, with 60-70% of that depletion being due to the thin microporous layer (MPL) on the catalyst layer (CL) side. Using concentration gradient data, we quantify the non-uniform local transport resistance across the DM and relate it to high resolution 3D X-ray computed tomography of the same DM.

  1. Electricity generation and bivalent copper reduction as a function of operation time and cathode electrode material in microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Wu, Dan; Huang, Liping; Quan, Xie; Li Puma, Gianluca

    2016-03-01

    The performance of carbon rod (CR), titanium sheet (TS), stainless steel woven mesh (SSM) and copper sheet (CS) cathode materials are investigated in microbial fuel cells (MFCs) for simultaneous electricity generation and Cu(II) reduction, in multiple batch cycle operations. After 12 cycles, the MFC with CR exhibits 55% reduction in the maximum power density and 76% increase in Cu(II) removal. In contrast, the TS and SSM cathodes at cycle 12 show maximum power densities of 1.7 (TS) and 3.4 (SSM) times, and Cu(II) removal of 1.2 (TS) and 1.3 (SSM) times higher than those observed during the first cycle. Diffusional resistance in the TS and SSM cathodes is found to appreciably decrease over time due to the copper deposition. In contrast to CR, TS and SSM, the cathode made with CS is heavily corroded in the first cycle, exhibiting significant reduction in both the maximum power density and Cu(II) removal at cycle 2, after which the performance stabilizes. These results demonstrate that the initial deposition of copper on the cathodes of MFCs is crucial for efficient and continuous Cu(II) reduction and electricity generation over prolonged time. This effect is closely associated with the nature of the cathode material. Among the materials examined, the SSM is the most effective and inexpensive cathode for practical use in MFCs.

  2. Development of portable fuel cells

    SciTech Connect

    Nakatou, K.; Sumi, S.; Nishizawa, N.

    1996-12-31

    Sanyo Electric has been concentrating on developing a marketable portable fuel cell using phosphoric acid fuel cells (PAFC). Due to the fact that this power source uses PAFC that operate at low temperature around 100{degrees} C, they are easier to handle compared to conventional fuel cells that operate at around 200{degrees} C , they can also be expected to provide extended reliable operation because corrosion of the electrode material and deterioration of the electrode catalyst are almost completely nonexistent. This power source is meant to be used independently and stored at room temperature. When it is started up, it generates electricity itself using its internal load to raise the temperature. As a result, the phosphoric acid (the electolyte) absorbs the reaction water when the temperature starts to be raised (around room temperature). At the same time the concentration and volume of the phosphoric acid changes, which may adversely affect the life time of the cell. We have studied means for starting, operating PAFC stack using methods that can simply evaluate changes in the concentration of the electrolyte in the stack with the aim of improving and extending cell life and report on them in this paper.

  3. Corrigendum to "Sinusoidal potential cycling operation of a direct ethanol fuel cell to improving carbon dioxide yields" [J. Power Sources 268 (5 December 2014) 439-442

    NASA Astrophysics Data System (ADS)

    Majidi, Pasha; Pickup, Peter G.

    2016-09-01

    The authors regret that Equation (5) is incorrect and has resulted in errors in Fig. 4 and the efficiencies stated on p. 442. The corrected equation, figure and text are presented below. In addition, the title should be 'Sinusoidal potential cycling operation of a direct ethanol fuel cell to improve carbon dioxide yields', and the reversible cell potential quoted on p. 441 should be 1.14 V. The authors would like to apologise for any inconvenience caused.

  4. Regenerative fuel cell engineering - FY99

    SciTech Connect

    Michael A. Inbody; Rodney L. Borup; James C. Hedstrom; Jose Tafoya; Byron Morton; Lois Zook; Nicholas E. Vanderborgh

    2000-01-01

    The authors report the work conducted by the ESA-EPE Fuel Cell Engineering Team at Los Alamos National Laboratory during FY99 on regenerative fuel cell system engineering. The work was focused on the evaluation of regenerative fuel cell system components obtained through the RAFCO program. These components included a 5 kW PEM electrolyzer, a two-cell regenerative fuel cell stack, and samples of the electrolyzer membrane, anode, and cathode. The samples of the electrolyzer membrane, anode, and cathode were analyzed to determine their structure and operating characteristics. Tests were conducted on the two-cell regenerative fuel cell stack to characterize its operation as an electrolyzer and as a fuel cell. The 5 kW PEM electrolyzer was tested in the Regenerative Fuel Cell System Test Facility. These tests served to characterize the operation of the electrolyzer and, also, to verify the operation of the newly completed test facility. Future directions for this work in regenerative fuel cell systems are discussed.

  5. Fuel cell system

    DOEpatents

    Early, Jack; Kaufman, Arthur; Stawsky, Alfred

    1982-01-01

    A fuel cell system is comprised of a fuel cell module including sub-stacks of series-connected fuel cells, the sub-stacks being held together in a stacked arrangement with cold plates of a cooling means located between the sub-stacks to function as electrical terminals. The anode and cathode terminals of the sub-stacks are connected in parallel by means of the coolant manifolds which electrically connect selected cold plates. The system may comprise a plurality of the fuel cell modules connected in series. The sub-stacks are designed to provide a voltage output equivalent to the desired voltage demand of a low voltage, high current DC load such as an electrolytic cell to be driven by the fuel cell system. This arrangement in conjunction with switching means can be used to drive a DC electrical load with a total voltage output selected to match that of the load being driven. This arrangement eliminates the need for expensive voltage regulation equipment.

  6. Comparative analysis of selected fuel cell vehicles

    SciTech Connect

    1993-05-07

    Vehicles powered by fuel cells operate more efficiently, more quietly, and more cleanly than internal combustion engines (ICEs). Furthermore, methanol-fueled fuel cell vehicles (FCVs) can utilize major elements of the existing fueling infrastructure of present-day liquid-fueled ICE vehicles (ICEVs). DOE has maintained an active program to stimulate the development and demonstration o fuel cell technologies in conjunction with rechargeable batteries in road vehicles. The purpose of this study is to identify and assess the availability of data on FCVs, and to develop a vehicle subsystem structure that can be used to compare both FCVs and ICEV, from a number of perspectives--environmental impacts, energy utilization, materials usage, and life cycle costs. This report focuses on methanol-fueled FCVs fueled by gasoline, methanol, and diesel fuel that are likely to be demonstratable by the year 2000. The comparative analysis presented covers four vehicles--two passenger vehicles and two urban transit buses. The passenger vehicles include an ICEV using either gasoline or methanol and an FCV using methanol. The FCV uses a Proton Exchange Membrane (PEM) fuel cell, an on-board methanol reformer, mid-term batteries, and an AC motor. The transit bus ICEV was evaluated for both diesel and methanol fuels. The transit bus FCV runs on methanol and uses a Phosphoric Acid Fuel Cell (PAFC) fuel cell, near-term batteries, a DC motor, and an on-board methanol reformer. 75 refs.

  7. Computational design and optimization of fuel cells and fuel cell systems: A review

    NASA Astrophysics Data System (ADS)

    Secanell, M.; Wishart, J.; Dobson, P.

    The design of fuel cells is a challenging endeavour due to the multitude of physical phenomena that need to be simultaneously optimized in order to achieve proper fuel cell operation. Fuel cell design is a multi-objective, multi-variable problem. In order to design fuel cells by computational design, a mathematical formulation of the design problem needs to be developed. The problem can then be solved using numerical optimization algorithms and a computational fuel cell model. In the past decade, the fuel cell community has gained momentum in the area of numerical design. In this article, research aimed at using numerical optimization to design fuel cells and fuel cell systems is reviewed. The review discusses the strengths, limitations, advantages, and disadvantages of optimization formulations and numerical optimization algorithms, and insight obtained from previous studies.

  8. TECHNICAL ASSESSMENT OF FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS AT THE YONKERS, NY, WASTEWATER TREATMENT PLANT

    EPA Science Inventory

    The paper summarizes the results of a 2-year field test to assess the performance of a specially modified commercial phosphoric acid 200 kW fuel cell power plant to recover energy from anaerobic digester gas (ADG) which has been cleansed of contaminants (sulfur and halide compoun...

  9. Towards neat methanol operation of direct methanol fuel cells: a novel self-assembled proton exchange membrane.

    PubMed

    Li, Jing; Cai, Weiwei; Ma, Liying; Zhang, Yunfeng; Chen, Zhangxian; Cheng, Hansong

    2015-04-18

    We report here a novel proton exchange membrane with remarkably high methanol-permeation resistivity and excellent proton conductivity enabled by carefully designed self-assembled ionic conductive channels. A direct methanol fuel cell utilizing the membrane performs well with a 20 M methanol solution, very close to the concentration of neat methanol.

  10. TECHNICAL ASSESSMENT OF FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS AT THE YONKERS, NY, WASTEWATER TREATMENT PLANT

    EPA Science Inventory

    The paper summarizes the results of a 2-year field test to assess the performance of a specially modified commercial phosphoric acid 200 kW fuel cell power plant to recover energy from anaerobic digester gas (ADG) which has been cleansed of contaminants (sulfur and halide compoun...

  11. Fuel cell system combustor

    DOEpatents

    Pettit, William Henry

    2001-01-01

    A fuel cell system including a fuel reformer heated by a catalytic combustor fired by anode and cathode effluents. The combustor includes a turbulator section at its input end for intimately mixing the anode and cathode effluents before they contact the combustors primary catalyst bed. The turbulator comprises at least one porous bed of mixing media that provides a tortuous path therethrough for creating turbulent flow and intimate mixing of the anode and cathode effluents therein.

  12. Fuel cell system configurations

    DOEpatents

    Kothmann, Richard E.; Cyphers, Joseph A.

    1981-01-01

    Fuel cell stack configurations having elongated polygonal cross-sectional shapes and gaskets at the peripheral faces to which flow manifolds are sealingly affixed. Process channels convey a fuel and an oxidant through longer channels, and a cooling fluid is conveyed through relatively shorter cooling passages. The polygonal structure preferably includes at least two right angles, and the faces of the stack are arranged in opposite parallel pairs.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. Ceramic fuel cells for stationary and mobile applications

    SciTech Connect

    Singhal, Subhash C. )

    2003-11-01

    Fuel cells are newsworthy because of high gasoline prices and concern about the environment. Several questions arise when fuel cells are discussed: - What are fuel cells? - What is the current status of fuel cells? - What fuel cell designs are being pursued by various organizations worldwide? - What are the advantages and disadvantages of the various fuel cell designs? - What size power systems have been produced and how well have they operated? Fuel cells are electrochemical energy conversion devices that directly convert chemical energy of a fuel to electricity, without combustion of the fuel. In this sense, they are similar to batteries. However, unlike a battery, where life is limited by the amount of chemical that is stored in it, fuel cells produce electricity as long as fuel is supplied. Thus, one might say that fuel cells are continuous batteries. Like batteries, there are many types of fuel cells: - Polymer electrolyte fuel cells are the most commonly discussed in the general interest media--newspapers, magazines and television. These fuel cells operate at {approx}90 degrees C and are the primary candidates for use in automobiles. - Alkaline fuel cells have been used in our space program since the early days of the Gemini and Apollo missions. - Phosphoric acid fuel cells are currently the most advanced on the market and are being commercialized by a division of United Technologies. - Solid oxide fuel cells (SOFCs) are based on zirconia electrolyte. This article concentrates on ceramic SOFCs.

  15. Effect of carbon deposition by carbon monoxide disproportionation on electrochemical characteristics at low temperature operation for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Sumi, Hirofumi; Lee, Yi-Hsuan; Muroyama, Hiroki; Matsui, Toshiaki; Kamijo, Motohisa; Mimuro, Shin; Yamanaka, Mitsugu; Nakajima, Yasushi; Eguchi, Koichi

    2011-05-01

    The deterioration by carbon deposition was evaluated for electrolyte- and anode-supported solid oxide fuel cells (SOFCs) in comparison with carbon monoxide disproportionation and methane cracking. The polarization resistance of the nickel-yttria stabilized zirconia (Ni-YSZ) anode increased with a rise in CO concentration in H2-CO-CO2 mixture for the electrolyte-supported cells at 923 K. The resistance, however, did not change against CO concentration for the anode-supported cells. In a methane fuel with a steam/carbon (S/C) ratio of 0.1, the cell performance decreased for both of the cells at 1073 K. A large amount of agglomerated amorphous carbon was deposited from the anode surface to the interface between the anode and the electrolyte after power generation at S/C = 0.1 in methane fuel. On the other hand, the crystalline graphite was deposited only at the anode surface for the anode-supported cell after power generation in CO-CO2 mixture. These results suggest that the reaction rate of CO disproportionation is faster than that of methane cracking. The deposited carbon near the anode/electrolyte interface caused the increase in the polarization resistance.

  16. Carbon-based Fuel Cell

    SciTech Connect

    Steven S. C. Chuang

    2005-08-31

    The direct use of coal in the solid oxide fuel cell to generate electricity is an innovative concept for power generation. The C-fuel cell (carbon-based fuel cell) could offer significant advantages: (1) minimization of NOx emissions due to its operating temperature range of 700-1000 C, (2) high overall efficiency because of the direct conversion of coal to CO{sub 2}, and (3) the production of a nearly pure CO{sub 2} exhaust stream for the direct CO{sub 2} sequestration. The objective of this project is to determine the technical feasibility of using a highly active anode catalyst in a solid oxide fuel for the direct electrochemical oxidation of coal to produce electricity. Results of this study showed that the electric power generation from Ohio No 5 coal (Lower Kittanning) Seam, Mahoning County, is higher than those of coal gas and pure methane on a solid oxide fuel cell assembly with a promoted metal anode catalyst at 950 C. Further study is needed to test the long term activity, selectivity, and stability of anode catalysts.

  17. Development of PEM fuel cell technology at international fuel cells

    SciTech Connect

    Wheeler, D.J.

    1996-04-01

    The PEM technology has not developed to the level of phosphoric acid fuel cells. Several factors have held the technology development back such as high membrane cost, sensitivity of PEM fuel cells to low level of carbon monoxide impurities, the requirement to maintain full humidification of the cell, and the need to pressurize the fuel cell in order to achieve the performance targets. International Fuel Cells has identified a hydrogen fueled PEM fuel cell concept that leverages recent research advances to overcome major economic and technical obstacles.

  18. Transient analysis of gas transport in anode channel of a polymer electrolyte membrane fuel cell with dead-ended anode under pressure swing operation

    NASA Astrophysics Data System (ADS)

    Ichikawa, Yasushi; Oshima, Nobuyuki; Tabuchi, Yuichiro; Ikezoe, Keigo

    2014-12-01

    Further cost reduction is a critical issue for commercialization of fuel-cell electric vehicles (FCEVs) based on polymer electrolyte fuel cells (PEFCs). The cost of the fuel-cell system is driven by the multiple parts required to maximize stack performance and maintain durability and robustness. The fuel-cell system of the FCEV must be simplified while maintaining functionality. The dead-ended anode is considered as a means of simplification in this study. Generally, if hydrogen is supplied under constant pressure during dead-ended operation, stable power generation is impossible because of accumulation of liquid water produced by power generation and of nitrogen via leakage from the cathode through the membrane. Herein, pressure oscillation is applied to address this issue. Empirical and CFD data are employed to elucidate the mechanism of stable power generation using the pressure swing supply. Simultaneous and time-continuous measurements of the current distribution and gas concentration distribution are also conducted. The results demonstrate that the nitrogen concentration in the anode channel under pressure constant operation differs from that under pressure swing supply conditions. The transient two-dimensional CFD results indicate that oscillatory flow is generated by pressure swing supply, which periodically sweeps out nitrogen from the active area, resulting in stable power generation.

  19. Fuels for fuel cells: Fuel and catalyst effects on carbon formation

    SciTech Connect

    Borup, R. L.; Inbody, M. A.; Perry, W. L.; Parkinson, W. J. ,

    2002-01-01

    The goal of this research is to explore the effects of fuels, fuel constituents, additives and impurities on the performance of on-board hydrogen generation devices and consequently on the overall performance of fuel cell systems using reformed hydrocarbon fuels. Different fuels and components have been tested in automotive scale, adiabatic autothermal reactors to observe their relative reforming characteristics with various operating conditions. Carbon formation has been modeled and was experimentally monitored in situ during operation by laser measurements of the effluent reformate. Ammonia formation was monitored, and conditions varied to observe under what conditions N H 3 is made.

  20. Fuel economy and range estimates for fuel cell powered automobiles

    SciTech Connect

    Steinbugler, M.; Ogden, J.

    1996-12-31

    While a number of automotive fuel cell applications have been demonstrated, including a golf cart, buses, and a van, these systems and others that have been proposed have utilized differing configurations ranging from direct hydrogen fuel cell-only power plants to fuel cell/battery hybrids operating on reformed methanol. To date there is no clear consensus on which configuration, from among the possible combinations of fuel cell, peaking device, and fuel type, is the most likely to be successfully commercialized. System simplicity favors direct hydrogen fuel cell vehicles, but infrastructure is lacking. Infrastructure favors a system using a liquid fuel with a fuel processor, but system integration and performance issues remain. A number of studies have analyzed particular configurations on either a system or vehicle scale. The objective of this work is to estimate, within a consistent framework, fuel economies and ranges for a variety of configurations using flexible models with the goal of identifying the most promising configurations and the most important areas for further research and development.

  1. Fuel economy of hybrid fuel-cell vehicles

    NASA Astrophysics Data System (ADS)

    Ahluwalia, Rajesh K.; Wang, X.; Rousseau, A.

    The potential improvement in fuel economy of a mid-size fuel-cell vehicle by combining it with an energy storage system has been assessed. An energy management strategy is developed and used to operate the direct hydrogen, pressurized fuel-cell system in a load-following mode and the energy storage system in a charge-sustaining mode. The strategy places highest priority on maintaining the energy storage system in a state where it can supply unanticipated boost power when the fuel-cell system alone cannot meet the power demand. It is found that downsizing a fuel-cell system decreases its efficiency on a drive cycle which is compensated by partial regenerative capture of braking energy. On a highway cycle with limited braking energy the increase in fuel economy with hybridization is small but on the stop-and-go urban cycle the fuel economy can improve by 27%. On the combined highway and urban drive cycles the fuel economy of the fuel-cell vehicle is estimated to increase by up to 15% by hybridizing it with an energy storage system.

  2. Carbon fuel cells with carbon corrosion suppression

    DOEpatents

    Cooper, John F [Oakland, CA

    2012-04-10

    An electrochemical cell apparatus that can operate as either a fuel cell or a battery includes a cathode compartment, an anode compartment operatively connected to the cathode compartment, and a carbon fuel cell section connected to the anode compartment and the cathode compartment. An effusion plate is operatively positioned adjacent the anode compartment or the cathode compartment. The effusion plate allows passage of carbon dioxide. Carbon dioxide exhaust channels are operatively positioned in the electrochemical cell to direct the carbon dioxide from the electrochemical cell.

  3. Fuel Cell Electrodes for Hydrogen-Air Fuel Cell Assemblies.

    DTIC Science & Technology

    The report describes the design and evaluation of a hydrogen-air fuel cell module for use in a portable hydrid fuel cell -battery system. The fuel ... cell module consists of a stack of 20 single assemblies. Each assembly contains 2 electrically independent cells with a common electrolyte compartment

  4. Cell module and fuel conditioner development

    NASA Technical Reports Server (NTRS)

    Feret, J. M.

    1981-01-01

    A phosphoric acid fuel cell (PAFC) stack design having a 10 kW power rating for operation at higher than atmospheric pressure based on the existing Mark II design configuration is described. Functional analysis, trade studies and thermodynamic cycle analysis for requirements definition and system operating parameter selection purposes were performed. Fuel cell materials and components, and performance testing and evaluation of the repeating electrode components were characterized. The state of the art manufacturing technology for all fuel cell components and the fabrication of short stacks of various sites were established. A 10 kW PAFC stack design for higher pressure operation utilizing the top down systems engineering aproach was developed.

  5. Single module pressurized fuel cell turbine generator system

    DOEpatents

    George, Raymond A.; Veyo, Stephen E.; Dederer, Jeffrey T.

    2001-01-01

    A pressurized fuel cell system (10), operates within a common pressure vessel (12) where the system contains fuel cells (22), a turbine (26) and a generator (98) where preferably, associated oxidant inlet valve (52), fuel inlet valve (56) and fuel cell exhaust valve (42) are outside the pressure vessel.

  6. Performance characteristics of part-load operations of a solid oxide fuel cell/gas turbine hybrid system using air-bypass valves

    NASA Astrophysics Data System (ADS)

    Yang, Jin Sik; Sohn, Jeong L.; Ro, Sung Tack

    In spite of the high-performance characteristics of a solid oxide fuel cell/gas turbine (SOFC/GT) hybrid system, it is difficult to maintain high-level performance under real application conditions, which generally require part-load operations. The efficiency loss of the SOFC/GT hybrid system under such conditions is closely related to that of the gas turbine. The power generated by the gas turbine in a hybrid system is much less than that generated by the SOFC, but its contribution to the efficiency of the system is important, especially under part-load conditions. Over the entire operating load profile of a hybrid system, the efficiency of the hybrid system can be maximized by increasing the contribution of power coming from the high efficiency component, namely the fuel cell. In this study, part-load control strategies using air-bypass valves are proposed, and their impact on the performance of an SOFC/GT hybrid system is discussed. It is found that air-bypass modes with control of the fuel supply help to overcome the limits of the part-load operation characteristics in air/fuel control modes, such as variable rotational speed control and variable inlet guide vane control.

  7. Fuel cells - Fundamentals and types: Unique features

    NASA Astrophysics Data System (ADS)

    Selman, J. R.

    An overview of the working principles, thermodynamic efficiencies, types, and engineering aspects of fuel cells is presented. It is noted that fuel cells are distinguished from other direct energy conversion devices by the existence of charge separation at the electrodes involving ions in an electrolyte. The electrical energy produced by a fuel cell is shown to be equal to the change in the free energy of the reactants, and thermodynamic balances of reactions in different fuel cells are provided. The production of electricity in the discharge mode involves a spontaneous reaction of overproduction of electrons at the anode and consumption of the electrons at the cathode, with the total ionic current being equal to the electronic current in the external circuit. Attention is given to the operations and problems of acid, alkaline, molten carbonate, and solid oxide fuel cells, in addition to applications of electro-organic fuel cells.

  8. Adaptation of a commercially available 200 kW natural gas fuel cell power plant for operation on a hydrogen rich gas stream

    SciTech Connect

    Maston, V.A.

    1997-12-01

    International Fuel Cells (IFC) has designed a hydrogen fueled fuel cell power plant based on a modification of its standard natural gas fueled PC25{trademark} C fuel cell power plant. The natural gas fueled PC25 C is a 200 kW, fuel cell power plant that is commercially available. The program to accomplish the fuel change involved deleting the natural gas processing elements, designing a new fuel pretreatment subsystem, modifying the water and thermal management subsystem, developing a hydrogen burner to combust unconsumed hydrogen, and modifying the control system. Additionally, the required modifications to the manufacturing and assembly procedures necessary to allow the hydrogen fueled power plant to be manufactured in conjunction with the on-going production of the standard PC25 C power plants were identified. This work establishes the design and manufacturing plan for the 200 kW hydrogen fueled PC25 power plant.

  9. Bi-Cell Unit for Fuel Cell.

    DTIC Science & Technology

    The patent concerns a bi-cell unit for a fuel cell . The bi-cell unit is comprised of two electrode packs. Each of the electrode packs includes an...invention relates in general to a bi-cell unit for a fuel cell and in particular, to a bi-cell unit for a hydrazine-air fuel cell .

  10. Integrated gasification fuel cell (IGFC) demonstration test

    SciTech Connect

    Steinfeld, G.; Ghezel-Ayagh, H.; Sanderson, R.; Abens, S.

    2000-07-01

    As concern about the environment generates interest in ultra-clean energy plants, fuel cell power plants can respond to the challenge. Fuel cells convert hydrocarbon fuels to electricity at efficiencies exceeding conventional heat engine technologies while generating extremely low emissions. Emissions of SOx and NOx are expected to be well below current and anticipated future standards. Nitrogen oxides, a product of combustion, will be extremely low in this power plant because power is produced electrochemically rather than by combustion. Due to its higher efficiencies, a fuel cell power plant also produces less carbon dioxide. Fuel cells in combination with coal gasification, are an efficient and environmentally acceptable means to utilize the abundant coal reserves both in the US and around the world. To demonstrate this technology, FuelCell Energy, Inc. (FCE), is planning to build and test a 2-MW Fuel Cell Power Plant for operation on coal derived gas. This power plant is based on Direct Fuel Cell (DFC{trademark}) technology and will be part of a Clean Coal V IGCC project supported by the US DOE. A British Gas Lurgi (BGL) slagging fixed-bed gasification system with cold gas clean up is planned as part of a 400 MW IGCC power plant to provide a fuel gas slip stream to the fuel cell. The IGFC power plant will be built by Kentucky Pioneer Energy, A subsidiary of Global Energy, in Clark County, KY. This demonstration will result in the world's largest fuel cell power plant operating on coal derived gas. The objective of this test is to demonstrate fuel cell operation on coal derived gas at a commercial scale and to verify the efficiency and environmental benefits.

  11. Fuel cell having dual electrode anode or cathode

    DOEpatents

    Findl, E.

    1984-04-10

    A fuel cell that is characterized by including a dual electrode anode that is operable to simultaneously electro-oxidize a gaseous fuel and a liquid fuel. In alternative embodiments, a fuel cell having a single electrode anode is provided with a dual electrode cathode that is operable to simultaneously reduce a gaseous oxidant and a liquid oxidant to electro-oxidize a fuel supplied to the cell.

  12. Fuel cell having dual electrode anode or cathode

    DOEpatents

    Findl, Eugene

    1985-01-01

    A fuel cell that is characterized by including a dual electrode anode that is operable to simultaneously electro-oxidize a gaseous fuel and a liquid fuel. In alternative embodiments, a fuel cell having a single electrode anode is provided with a dual electrode cathode that is operable to simultaneously reduce a gaseous oxidant and a liquid oxidant to electro-oxidize a fuel supplied to the cell.

  13. Advanced fuel cell development

    NASA Astrophysics Data System (ADS)

    Ackerman, J. P.; Pierce, R. D.; Fee, D. C.

    1984-02-01

    Research and development activities on both molten carbonate and solid oxide fuel cells is reported. The efforts on development of molten carbonate fuel cells have been directed principally toward seeking alternative cathode materials to NiO. Based on an investigation of the thermodynamically stable phases formed under cathode conditions with a number of transition metal oxides, synthesis of prospective alternative cathode materials and doping of these materials to promote electronic conductivity is under way. The compounds LiFeO2, Li2MnO3, and ZnO have been doped to give suitable conductivity. Solubility data were taken for NiO, CoO, and NiO-CoO in a cathode environment with different carbonate salt compositions. Techniques are for the preparation of thin electrode and electrolyte materials by tape casting, and a creep resistant superstructure for the anode are studied. Development of an advanced, high power density fuel cell is examined. By employing the thin ceramic layer components of existing solid oxide fuel cells in a strong, lightweight structure of small cells, unequaled power per unit mass or volume can be achieved. Advanced electrolyte fabrication, electrolyte sintering and interconnection and electrode fabrication were investigated.

  14. Fuel cell membranes and crossover prevention

    DOEpatents

    Masel, Richard I.; York, Cynthia A.; Waszczuk, Piotr; Wieckowski, Andrzej

    2009-08-04

    A membrane electrode assembly for use with a direct organic fuel cell containing a formic acid fuel includes a solid polymer electrolyte having first and second surfaces, an anode on the first surface and a cathode on the second surface and electrically linked to the anode. The solid polymer electrolyte has a thickness t:.gtoreq..times..times..times..times. ##EQU00001## where C.sub.f is the formic acid fuel concentration over the anode, D.sub.f is the effective diffusivity of the fuel in the solid polymer electrolyte, K.sub.f is the equilibrium constant for partition coefficient for the fuel into the solid polymer electrolyte membrane, I is Faraday's constant n.sub.f is the number of electrons released when 1 molecule of the fuel is oxidized, and j.sub.f.sup.c is an empirically determined crossover rate of fuel above which the fuel cell does not operate.

  15. Fuel cell membranes and crossover prevention

    DOEpatents

    Masel, Richard I.; York, Cynthia A.; Waszczuk, Piotr; Wieckowski, Andrzej

    2009-08-04

    A membrane electrode assembly for use with a direct organic fuel cell containing a formic acid fuel includes a solid polymer electrolyte having first and second surfaces, an anode on the first surface and a cathode on the second surface and electrically linked to the anode. The solid polymer electrolyte has a thickness t:.gtoreq..times..times..times..times. ##EQU00001## where C.sub.f is the formic acid fuel concentration over the anode, D.sub.f is the effective diffusivity of the fuel in the solid polymer electrolyte, K.sub.f is the equilibrium constant for partition coefficient for the fuel into the solid polymer electrolyte membrane, I is Faraday's constant n.sub.f is the number of electrons released when 1 molecule of the fuel is oxidized, and j.sub.f.sup.c is an empirically determined crossover rate of fuel above which the fuel cell does not operate.

  16. Annular feed air breathing fuel cell stack

    DOEpatents

    Wilson, Mahlon S.; Neutzler, Jay K.

    1997-01-01

    A stack of polymer electrolyte fuel cells is formed from a plurality of unit cells where each unit cell includes fuel cell components defining a periphery and distributed along a common axis, where the fuel cell components include a polymer electrolyte membrane, an anode and a cathode contacting opposite sides of the membrane, and fuel and oxygen flow fields contacting the anode and the cathode, respectively, wherein the components define an annular region therethrough along the axis. A fuel distribution manifold within the annular region is connected to deliver fuel to the fuel flow field in each of the unit cells. The fuel distribution manifold is formed from a hydrophilic-like material to redistribute water produced by fuel and oxygen reacting at the cathode. In a particular embodiment, a single bolt through the annular region clamps the unit cells together. In another embodiment, separator plates between individual unit cells have an extended radial dimension to function as cooling fins for maintaining the operating temperature of the fuel cell stack.

  17. Mathematical modeling of solid oxide fuel cells

    NASA Technical Reports Server (NTRS)

    Lu, Cheng-Yi; Maloney, Thomas M.

    1988-01-01

    Development of predictive techniques, with regard to cell behavior, under various operating conditions is needed to improve cell performance, increase energy density, reduce manufacturing cost, and to broaden utilization of various fuels. Such technology would be especially beneficial for the solid oxide fuel cells (SOFC) at it early demonstration stage. The development of computer models to calculate the temperature, CD, reactant distributions in the tubular and monolithic SOFCs. Results indicate that problems of nonuniform heat generation and fuel gas depletion in the tubular cell module, and of size limitions in the monolithic (MOD 0) design may be encountered during FC operation.

  18. Compact fuel cell

    DOEpatents

    Jacobson, Craig; DeJonghe, Lutgard C.; Lu, Chun

    2010-10-19

    A novel electrochemical cell which may be a solid oxide fuel cell (SOFC) is disclosed where the cathodes (144, 140) may be exposed to the air and open to the ambient atmosphere without further housing. Current collector (145) extends through a first cathode on one side of a unit and over the unit through the cathode on the other side of the unit and is in electrical contact via lead (146) with housing unit (122 and 124). Electrical insulator (170) prevents electrical contact between two units. Fuel inlet manifold (134) allows fuel to communicate with internal space (138) between the anodes (154 and 156). Electrically insulating members (164 and 166) prevent the current collector from being in electrical contact with the anode.

  19. Alternative fuels for mobile fuel cells

    NASA Astrophysics Data System (ADS)

    Calabrese Barton, Scott Andrew

    1999-11-01

    Because of limitations associated with the use of hydrogen fuel, the direct use of alternative fuels in fuel cells has been the focus of intense research. Two fuels worthy of consideration are methanol and zinc. This work considers aspects of implementing these fuels in mobile fuel cell applications. Two chapters treat topics relating to direct methanol fuel cells, and three chapters consider the cathode and anode of the zinc-air cell. A methanol concentration sensor is crucial to the control of a direct methanol fuel cell system. The design considered here is based on current output limited by methanol diffusion through a proton exchange membrane. The sensor provides first-order response to changes in concentration and temperature over a concentration range of 0 to 3 M, with a response on the order of 10 seconds. A mixed-reactant, strip-cell direct methanol fuel cell concept is discussed. In this type of cell, reaction-selective electrodes are mounted in an alternating fashion on the same side of a membrane electrolyte, allowing mixing of feed streams, and reduced system complexity. The performance of prototypical cells is demonstrated, and improved fuel efficiency at low current density is predicted. Geometric constraints on the performance of such cells are also considered. A primary zinc-air cell may be considered a fuel cell if the anode is replaceable. The cathode of such a cell is analyzed using a numerical model. Results indicate that oxygen solubility and diffusion in the electrolyte dominate polarization losses. Reduced catalyst particle size and decreased electrolyte concentration are suggested to improve cathode performance. Whereas the air cathode may be modeled adequately, given the wealth of information available on oxygen kinetics, the oxidation of zinc is not well-understood. Thus, the mass-transfer-limited region of zinc electrodissolution was investigated using a zinc rotating disk electrode and electrochemical impedance techniques. The zincate

  20. Residential Fuel Cell Demonstration Handbook

    NASA Astrophysics Data System (ADS)

    Torrero, E.; McClelland, R.

    2002-07-01

    This report is a guide for rural electric cooperatives engaged in field testing of equipment and in assessing related application and market issues. Dispersed generation and its companion fuel cell technology have attracted increased interest by rural electric cooperatives and their customers. In addition, fuel cells are a particularly interesting source because their power quality, efficiency, and environmental benefits have now been coupled with major manufacturer development efforts. The overall effort is structured to measure the performance, durability, reliability, and maintainability of these systems, to identify promising types of applications and modes of operation, and to assess the related prospect for future use. In addition, technical successes and shortcomings will be identified by demonstration participants and manufacturers using real-world experience garnered under typical operating environments.

  1. Trends in Operational Fuel Use

    DTIC Science & Technology

    2016-08-01

    As a result, the Secretary of the Navy created a Deputy Assistant Secretary for Energy, the CNO set the goal to reduce the Navy afloat fossil -fuel...3. CNA Research Memorandum DRM-2012-U-000275-Final. Prospects for Reduced Fossil Fuel Use Afloat. By Michael M. McCrea, LaVar Huntzinger, Katherine

  2. Operation of Thin-Film Electrolyte Metal-Supported Solid Oxide Fuel Cells in Lightweight and Stationary Stacks: Material and Microstructural Aspects

    PubMed Central

    Roehrens, Daniel; Packbier, Ute; Fang, Qingping; Blum, Ludger; Sebold, Doris; Bram, Martin; Menzler, Norbert

    2016-01-01

    In this study we report on the development and operational data of a metal-supported solid oxide fuel cell with a thin film electrolyte under varying conditions. The metal-ceramic structure was developed for a mobile auxiliary power unit and offers power densities of 1 W/cm2 at 800 °C, as well as robustness under mechanical, thermal and chemical stresses. A dense and thin yttria-doped zirconia layer was applied to a nanoporous nickel/zirconia anode using a scalable adapted gas-flow sputter process, which allowed the homogeneous coating of areas up to 100 cm2. The cell performance is presented for single cells and for stack operation, both in lightweight and stationary stack designs. The results from short-term operation indicate that this cell technology may be a very suitable alternative for mobile applications. PMID:28773883

  3. Operation of Thin-Film Electrolyte Metal-Supported Solid Oxide Fuel Cells in Lightweight and Stationary Stacks: Material and Microstructural Aspects.

    PubMed

    Roehrens, Daniel; Packbier, Ute; Fang, Qingping; Blum, Ludger; Sebold, Doris; Bram, Martin; Menzler, Norbert

    2016-09-08

    In this study we report on the development and operational data of a metal-supported solid oxide fuel cell with a thin film electrolyte under varying conditions. The metal-ceramic structure was developed for a mobile auxiliary power unit and offers power densities of 1 W/cm² at 800 °C, as well as robustness under mechanical, thermal and chemical stresses. A dense and thin yttria-doped zirconia layer was applied to a nanoporous nickel/zirconia anode using a scalable adapted gas-flow sputter process, which allowed the homogeneous coating of areas up to 100 cm². The cell performance is presented for single cells and for stack operation, both in lightweight and stationary stack designs. The results from short-term operation indicate that this cell technology may be a very suitable alternative for mobile applications.

  4. Regenerative fuel cell study

    NASA Technical Reports Server (NTRS)

    Wynveen, R. A.; Schubert, F. H.

    1972-01-01

    The completion of the study is reported for the regenerative fuel cell subsystem (RFCS) as an energy storage process for use aboard the space shuttle launched modular space station (MSS). The MSS mission requirements, and RFCS are discussed, and a comparison between RFCS and a nickel cadmium battery subsystem is presented. Development costs are also discussed.

  5. Local potential evolutions during proton exchange membrane fuel cell operation with dead-ended anode - Part I: Impact of water diffusion and nitrogen crossover

    NASA Astrophysics Data System (ADS)

    Abbou, S.; Dillet, J.; Maranzana, G.; Didierjean, S.; Lottin, O.

    2017-02-01

    Operating a PEMFC with a dead-ended anode may lead to local fuel-starvation because of water and possibly nitrogen accumulation in the anode compartment. In previous works, we used a segmented linear cell with reference electrodes to monitor simultaneously the local potentials and current densities during dead-ended anode operation. The results indicated that water transport as well as nitrogen crossover through the membrane were most probably the two key factors governing fuel starvation. In this first from a set of two papers, we evaluated with more details the contributions of nitrogen crossover and water transport to hydrogen starvation. To assess nitrogen contribution, the fuel cell cathode compartment was first supplied with pure oxygen instead of air. The results showed that in the absence of nitrogen (in the cathode side) the fuel starvation was much slower than with air, suggesting that nitrogen contribution cannot be neglected. On the other hand, the contribution of water flooding to hydrogen starvation was investigated by using different cooling temperature on the cathode and anode sides in order to drive water toward the colder plate. The results showed that with a colder anode side, fuel starvation was faster. In the opposite case of a hotter anode plate, water accumulation in the anode compartment was limited, nitrogen crossover through the membrane was the main reason for hydrogen starvation in this case. To fully assess the impact of the thermal configurations on membrane-electrode assembly (MEA) degradation, aging protocols with a dead-ended anode and a fixed closing time were also performed. The results showed that operation with a hotter anode could help to limit significantly cathode ElectroChemical Surface Area (ECSA) losses along the cell area and performance degradation induced by hydrogen starvation.

  6. Alternate switching between microbial fuel cell and microbial electrolysis cell operation as a new method to control H2O2 level in Bioelectro-Fenton system

    NASA Astrophysics Data System (ADS)

    Zhang, Yifeng; Wang, Yong; Angelidaki, Irini

    2015-09-01

    Sustainable H2O2 supply and cost-effective elimination of residual H2O2 are two key challenges associated with the successful application of Fenton reaction for contaminant removal. In this study, an innovative Bioelectro-Fenton system capable of alternate switching between microbial electrolysis cell (MEC) and microbial fuel cell (MFC) mode of operation was developed to meet the challenges. In the MEC mode, a bioelectrochemical system (BES) produces H2O2 which reacts with Fenton's reagent (Fe II) to form hydroxyradical. The unused H2O2 (residual H2O2) is removed as electron acceptor by switching the system to MFC mode of operation. Complete decolorization and mineralization of 50 mg L-1 methylene blue (MB) was achieved in the MEC mode with apparent first order rate constants of 0.43 and 0.22 h-1, respectively. After switching to the MFC mode, residual H2O2 of 180 mg L-1 was removed at a removal rate of 4.61 mg L-1 h-1 while generating a maximum current density of 0.49 A m-2. The MB degradation and residual H2O2 removal were affected by external resistance, cathode pH and initial MB concentration. Furthermore, the system performance was enhanced under stack operation. This study provides a proof-in-concept new system for efficient and cost-effective H2O2 control and recalcitrant pollutants removal.

  7. Interfacial material for solid oxide fuel cell

    DOEpatents

    Baozhen, Li; Ruka, Roswell J.; Singhal, Subhash C.

    1999-01-01

    Solid oxide fuel cells having improved low-temperature operation are disclosed. In one embodiment, an interfacial layer of terbia-stabilized zirconia is located between the air electrode and electrolyte of the solid oxide fuel cell. The interfacial layer provides a barrier which controls interaction between the air electrode and electrolyte. The interfacial layer also reduces polarization loss through the reduction of the air electrode/electrolyte interfacial electrical resistance. In another embodiment, the solid oxide fuel cell comprises a scandia-stabilized zirconia electrolyte having high electrical conductivity. The scandia-stabilized zirconia electrolyte may be provided as a very thin layer in order to reduce resistance. The scandia-stabilized electrolyte is preferably used in combination with the terbia-stabilized interfacial layer. The solid oxide fuel cells are operable over wider temperature ranges and wider temperature gradients in comparison with conventional fuel cells.

  8. Opportunities for portable Ballard Fuel Cells

    SciTech Connect

    Voss, H.H.; Huff, J.R.

    1996-12-31

    With the increasing proliferation and sophistication of portable electronic devices in both commercial and military markets, the need has arisen for small, lightweight power supplies that can provide increased operating life over those presently available. A solution to this power problem is the development of portable Ballard Fuel Cell power systems that operate with a hydrogen fuel source and air. Ballard has developed PEM fuel cell stacks and power systems in the 25 to 100 watt range for both of these markets. For military use, Ballard has teamed with Ball Corporation and Hydrogen Consultants, Inc. and has provided the Ballard Fuel Cell stack for an ambient PEM fuel cell power system for the DoD. The system provides power from idle to I 00 watts and has the capability of delivering overloads of 125 watts for short periods of time. The system is designed to operate over a wide range of temperature, relative humidity and altitude. Hydrogen is supplied as a compressed gas, metal hydride or chemical hydride packaged in a unit that is mated to the power/control unit. The hydrogen sources provide 1.5, 5 and 15 kWh of operation, respectively. The design of the fuel cell power system enables the unit to operate at 12 volts or 24 volts depending upon the equipment being used. For commercial applications, as with the military, fuel cell power sources in the 25 to 500 watt range will be competing with advanced batteries. Ambient PEM fuel cell designs and demonstrators are being developed at 25 watts and other low power levels. Goals are minimum stack volume and weight and greatly enhanced operating life with reasonable system weight and volume. This paper will discuss ambient PEM fuel cell designs and performance and operating parameters for a number of power levels in the multiwatt range.

  9. Mass transfer in fuel cells

    NASA Technical Reports Server (NTRS)

    Walker, R. D., Jr.

    1973-01-01

    Developments in the following areas are reported: surface area and pore size distribution in electrolyte matrices, electron microscopy of electrolyte matrices, surface tension of KOH solutions, water transport in fuel cells, and effectiveness factors for fuel cell components.

  10. Fuel Cell Technical Team Roadmap

    SciTech Connect

    2013-06-01

    The Fuel Cell Technical Team promotes the development of a fuel cell power system for an automotive powertrain that meets the U.S. DRIVE Partnership (United States Driving Research and Innovation for Vehicle efficiency and Energy sustainability) goals.

  11. Using Polymer Electrolyte Membrane Fuel Cells in a Hybrid Surface Ship Propulsion Plant to Increase Fuel Efficiency

    DTIC Science & Technology

    2010-06-01

    cell ( PEMFC ), and the phosphoric acid fuel cell (PAFC). 2.3.1 Solid Oxide Fuel Cells (SOFC) The first type of fuel cell considered is the SOFC. This...durability issues for use within a given application. 2.3.2 Polymer Electrolyte Membrane Fuel Cells ( PEMFC ) The PEMFC operates by passing hydrogen that has...cells. Some advantages of PEMFC operating at such low temperatures is that the fuel cell doesn’t require as meticulous of a support system infrastructure

  12. Biogas, compost and fuel cells

    SciTech Connect

    Wichert, B.; Wittrup, L.; Robel, R.

    1994-08-01

    A pilot project now under development in Folsom, California, incorporates an anaerobic digestion/aerobic composting process that could eventually supply enough biogas to a fuel cell. The Sacramento Municipal Utility District (SMUD) has two fuel cells in operation and is participating in the research project. Recently, the California Prison Industry Authority (PIA) began operating a processing facility at the Folsom prison, designed for 100 tons/day of mixed waste from the City of Folsom. The 35,000 square foot Correctional Resource Recovery Facility (CRRF) uses minimum security inmates from Folsom`s Return to Custody Facility to manually separate recyclables and compostable materials from the waste stream. The PIA will be using a new technology, high solids anaerobic digestion, to compost the organic fraction (representing approximately 60 to 70 percent of the waste stream). Construction began in June on a 40-foot wide by 120-foot long and 22-foot deep anaerobic digester. Once the vessel is operational in 1995, the composting process and the gradual breakdown of organic material will produce biogas, which SMUD hopes to use to power an adjacent two megawatt fuel cell. The electricity generated will serve SMUD customers, including the waste facility and nearby correctional institutions. 1 fig.

  13. Molten carbonate fuel cell improvements

    NASA Astrophysics Data System (ADS)

    Blurton, K. F.; Marianowski, L. G.

    It is noted that a molten carbonate fuel cell integrated with a coal gasification power plant is one of the most promising coal-using technologies because of its high efficiency, acceptable cost, and environmental acceptability. For the molten carbonate system to achieve these goals, however, continued development is required which must take into account the operating conditions of the application. The progress made in improving cell performance and life is surveyed, evaluating the effect of contaminants on cell performance and the design of multicell stacks and identifying alternative electrolyte compositions. Also discussed is the status of research on other major areas.

  14. Fuel cell generator with fuel electrodes that control on-cell fuel reformation

    DOEpatents

    Ruka, Roswell J.; Basel, Richard A.; Zhang, Gong

    2011-10-25

    A fuel cell for a fuel cell generator including a housing including a gas flow path for receiving a fuel from a fuel source and directing the fuel across the fuel cell. The fuel cell includes an elongate member including opposing first and second ends and defining an interior cathode portion and an exterior anode portion. The interior cathode portion includes an electrode in contact with an oxidant flow path. The exterior anode portion includes an electrode in contact with the fuel in the gas flow path. The anode portion includes a catalyst material for effecting fuel reformation along the fuel cell between the opposing ends. A fuel reformation control layer is applied over the catalyst material for reducing a rate of fuel reformation on the fuel cell. The control layer effects a variable reformation rate along the length of the fuel cell.

  15. Fuel cell generator

    DOEpatents

    Makiel, Joseph M.

    1985-01-01

    A high temperature solid electrolyte fuel cell generator comprising a housing means defining a plurality of chambers including a generator chamber and a combustion products chamber, a porous barrier separating the generator and combustion product chambers, a plurality of elongated annular fuel cells each having a closed end and an open end with the open ends disposed within the combustion product chamber, the cells extending from the open end through the porous barrier and into the generator chamber, a conduit for each cell, each conduit extending into a portion of each cell disposed within the generator chamber, each conduit having means for discharging a first gaseous reactant within each fuel cell, exhaust means for exhausting the combustion product chamber, manifolding means for supplying the first gaseous reactant to the conduits with the manifolding means disposed within the combustion product chamber between the porous barrier and the exhaust means and the manifolding means further comprising support and bypass means for providing support of the manifolding means within the housing while allowing combustion products from the first and a second gaseous reactant to flow past the manifolding means to the exhaust means, and means for flowing the second gaseous reactant into the generator chamber.

  16. Fuel Cell/Electrochemical Cell Voltage Monitor

    NASA Technical Reports Server (NTRS)

    Vasquez, Arturo

    2012-01-01

    A concept has been developed for a new fuel cell individual-cell-voltage monitor that can be directly connected to a multi-cell fuel cell stack for direct substack power provisioning. It can also provide voltage isolation for applications in high-voltage fuel cell stacks. The technology consists of basic modules, each with an 8- to 16-cell input electrical measurement connection port. For each basic module, a power input connection would be provided for direct connection to a sub-stack of fuel cells in series within the larger stack. This power connection would allow for module power to be available in the range of 9-15 volts DC. The relatively low voltage differences that the module would encounter from the input electrical measurement connection port, coupled with the fact that the module's operating power is supplied by the same substack voltage input (and so will be at similar voltage), provides for elimination of high-commonmode voltage issues within each module. Within each module, there would be options for analog-to-digital conversion and data transfer schemes. Each module would also include a data-output/communication port. Each of these ports would be required to be either non-electrical (e.g., optically isolated) or electrically isolated. This is necessary to account for the fact that the plurality of modules attached to the stack will normally be at a range of voltages approaching the full range of the fuel cell stack operating voltages. A communications/ data bus could interface with the several basic modules. Options have been identified for command inputs from the spacecraft vehicle controller, and for output-status/data feeds to the vehicle.

  17. Integrated regenerative fuel cell experimental evaluation

    NASA Technical Reports Server (NTRS)

    Martin, Ronald E.

    1990-01-01

    An experimental test program was conducted to investigate the performance characteristics of an integrated regenerative fuel cell (IRFC) concept. The IRFC consists of a separate fuel cell unit and electrolysis cell unit in the same structure, with internal storage of fuel cell product water and external storage of electrolysis cell produced hydrogen and oxygen. The fuel cell unit incorporates an enhanced Orbiter-type cell capable of improved performance at reduced weight. The electrolysis cell features a NiCo2O4 catalyst oxygen evolution eletrode with a porous Teflon cover to retard electrolyte loss. Six complete IRFC assemblies were assembled and performance tested at an operating temperature of 200 F (93.3 C) and reactant pressures up to 170 psia (117.2 n/cu cm) on IRFC No. 4. Anomalous pressure charge/discharge characteristics were encountered during performance evaluation. A reversible fuel cell incorporating a proprietary bi-functional oxygen electrode operated satisfactory at 200 F (93.3 C) at reactant pressures up to 50 psia (41.4 n/cu cm) as a regenerative fuel cell for one cycle, before developing an electrical short in the fuel cell mode. Electrolysis cell 300-hour endurance tests demonstrated the electrolyte retention capability of the electrode Teflon cover and the performance stability of the bi-functional oxygen electrode at high potential.

  18. The Direct Methanol Liquid-Feed Fuel Cell

    NASA Technical Reports Server (NTRS)

    Halpert, Gerald

    1997-01-01

    Until the early 1990's the idea of a practical direct methanol fuel cell from transportation and other applications was just that, an idea. Several types of fuel cells that operate under near ambient conditions were under development.

  19. Fuel cell membrane humidification

    DOEpatents

    Wilson, Mahlon S.

    1999-01-01

    A polymer electrolyte membrane fuel cell assembly has an anode side and a cathode side separated by the membrane and generating electrical current by electrochemical reactions between a fuel gas and an oxidant. The anode side comprises a hydrophobic gas diffusion backing contacting one side of the membrane and having hydrophilic areas therein for providing liquid water directly to the one side of the membrane through the hydrophilic areas of the gas diffusion backing. In a preferred embodiment, the hydrophilic areas of the gas diffusion backing are formed by sewing a hydrophilic thread through the backing. Liquid water is distributed over the gas diffusion backing in distribution channels that are separate from the fuel distribution channels.

  20. Inorganic salt mixtures as electrolyte media in fuel cells

    NASA Technical Reports Server (NTRS)

    Angell, Charles Austen (Inventor); Belieres, Jean-Philippe (Inventor); Francis-Gervasio, Dominic (Inventor)

    2012-01-01

    Fuel cell designs and techniques for converting chemical energy into electrical energy uses a fuel cell are disclosed. The designs and techniques include an anode to receive fuel, a cathode to receive oxygen, and an electrolyte chamber in the fuel cell, including an electrolyte medium, where the electrolyte medium includes an inorganic salt mixture in the fuel cell. The salt mixture includes pre-determined quantities of at least two salts chosen from a group consisting of ammonium trifluoromethanesulfonate, ammonium trifluoroacetate, and ammonium nitrate, to conduct charge from the anode to the cathode. The fuel cell includes an electrical circuit operatively coupled to the fuel cell to transport electrons from the cathode.

  1. Fuel cell systems program plan, Fiscal year 1994

    SciTech Connect

    Not Available

    1994-07-01

    Goal of the fuel cell program is to increase energy efficiency and economic effectiveness through development and commercialization of fuel cell systems which operate on fossil fuels in multiple end use sectors. DOE is participating with the private sector in sponsoring development of molten carbonate fuel cells and solid oxide fuel cells for application in the utility, commercial, and industrial sectors. Commercialization of phosphoric acid fuel cells is well underway. Besides the introduction, this document is divided into: goal/objectives, program strategy, technology description, technical status, program description/implementation, coordinated fuel cell activities, and international activities.

  2. Gasifiers optimized for fuel cell applications

    NASA Astrophysics Data System (ADS)

    Steinfeld, G.; Fruchtman, J.; Hauserman, W. B.; Lee, A.; Meyers, S. J.

    Conventional coal gasification carbonate fuel cell systems are typically configured so that the fuel gas is primarily hydrogen, carbon monoxide, and carbon dioxide, with waste heat recovery for process requirements and to produce additional power in a steam bottoming cycle. These systems make use of present day gasification processes to produce the low to medium Btu fuel gas which in turn is cleaned up and consumed by the fuel cell. These conventional gasification/fuel cell systems have been studied in recent years projecting system efficiencies of 45-53 percent (HHV). Conventional gasification systems currently available evolved as stand-alone systems producing low to medium Btu gas fuel gas. The requirements of the gasification process dictates high temperatures to carry out the steam/carbon reaction and to gasify the tars present in coal. The high gasification temperatures required are achieved by an oxidant which consumes a portion of the feed coal to provide the endothermic heat required for the gasification process. The thermal needs of this process result in fuel gas temperatures that are higher than necessary for most end use applications, as well as for gas cleanup purposes. This results in some efficiency and cost penalties. This effort is designed to study advanced means of power generation by integrating the gasification process with the unique operating characteristics of carbonate fuel cells to achieve a more efficient and cost effective coal based power generating system. This is to be done by altering the gasification process to produce fuel gas compositions which result in more efficient fuel cell operation and by integrating the gasification process with the fuel cell as shown in Figure 2. Low temperature catalytic gasification was chosen as the basis for this effort due to the inherent efficiency advantages and compatibility with fuel cell operating temperatures.

  3. Hydrogen production from formic acid in pH-stat fed-batch operation for direct supply to fuel cell.

    PubMed

    Shin, Jong-Hwan; Yoon, Jong Hyun; Lee, Seung Hoon; Park, Tai Hyun

    2010-01-01

    Enterobacter asburiae SNU-1 harvested after cultivation was used as a whole cell biocatalyst, for the production of hydrogen. Formic acid was efficiently converted to hydrogen using the harvested cells with an initial hydrogen production rate and total hydrogen production of 491 ml/l/h and 6668 ml/l, respectively, when 1 g/l of whole cell enzyme was used. Moreover, new pH-stat fed-batch operation was conducted, and total hydrogen production was 1.4 times higher than that of batch operation. For practical application, bio-hydrogen produced from formic acid using harvested cells was directly applied to PEMFC for power generation.

  4. Fuel cell report to congress

    SciTech Connect

    None, None

    2003-02-28

    This report describes the status of fuel cells for Congressional committees. It focuses on the technical and economic barriers to the use of fuel cells in transportation, portable power, stationary, and distributed power generation applications, and describes the need for public-private cooperative programs to demonstrate the use of fuel cells in commercial-scale applications by 2012. (Department of Energy, February 2003).

  5. Fuel cell sub-assembly

    DOEpatents

    Chi, Chang V.

    1983-01-01

    A fuel cell sub-assembly comprising a plurality of fuel cells, a first section of a cooling means disposed at an end of the assembly and means for connecting the fuel cells and first section together to form a unitary structure.

  6. Advanced fuel cell development

    NASA Astrophysics Data System (ADS)

    1984-06-01

    Fuel cell research and development activities at Argonne National Laboratory (ANL) during the period July through September 1983 are discussed. These efforts were directed principally toward seeking alternative cathode materials to NiO for molten carbonate fuel cells. An investigation was made of the thermodynamically stable phases formed under cathode conditions with a number of transition metal oxides. Prospective alternative cathode materials are being synthesized and doped to promote electronic conductivity. Three materials-LiFeO2, Li2MnO3, and ZnO were doped to give suitable conductivity. These materials are being further tested for solubility and ion migration in the cell environment. Techniques are being studied for the preparation of thin electrode and electrolyte materials by tape casting, and a creep-resistant superstructure for the anode is under development.

  7. Fuel cell technology program

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A fuel cell technology program was established to advance the state-of-the-art of hydrogen-oxygen fuel cells using low temperature, potassium hydroxide electrolyte technology as the base. Program tasks are described consisting of baseline cell design and stack testing, hydrogen pump design and testing, and DM-2 powerplant testing and technology extension efforts. A baseline cell configuration capable of a minimum of 2000 hours of life was defined. A 6-cell prototype stack, incorporating most of the scheme cell features, was tested for a total of 10,497 hours. A 6-cell stack incorporating all of the design features was tested. The DM-2 powerplant with a 34 cell stack, an accessory section packaged in the basic configuration anticipated for the space shuttle powerplant and a powerplant control unit, was defined, assembled, and tested. Cells were used in the stack and a drag-type hydrogen pump was installed in the accessory section. A test program was established, in conjunction with NASA/JSC, based on space shuttle orbiter mission. A 2000-hour minimum endurance test and a 5000-hour goal were set and the test started on August 8, 1972. The 2000-hour milestone was completed on November 3, 1972. On 13 March 1973, at the end of the thirty-first simulated seven-day mission and 5072 load hours, the test was concluded, all goals having been met. At this time, the DM-2 was in excellent condition and capable of additional endurance.

  8. Aluminum oxide as a dual-functional modifier of Ni-based anodes of solid oxide fuel cells for operation on simulated biogas

    NASA Astrophysics Data System (ADS)

    Wang, Feng; Wang, Wei; Ran, Ran; Tade, Moses O.; Shao, Zongping

    2014-12-01

    Al2O3 and SnO2 additives are introduced into the Ni-YSZ cermet anode of solid oxide fuel cells (SOFCs) for operation on simulated biogas. The effects of incorporating Al2O3/SnO2 on the electrical conductivity, morphology, coking resistance and catalytic activity for biogas reforming of the cermet anode are systematically studied. The electrochemical performance of the internal reforming SOFC is enhanced by introducing an appropriate amount of Al2O3 into the anode, but it becomes worse with excess alumina addition. For SnO2, a negative effect on the electrochemical performance is demonstrated, although the coking resistance of the anode is improved. For fuel cells operating on biogas, stable operation under a polarization current for 130 h at 750 °C is achieved for a cell with an Al2O3-modified anode, while cells with unmodified or SnO2-modified Ni-YSZ anodes show much poorer stability under the same conditions. The improved performance of the cell with the Al2O3-modified anode mainly results from the suppressed coking and sintering of the anode and from the formation of NiAl2O4 in the unreduced anode. In sum, modifying the anode with Al2O3 may be a useful and facile way to improve the coking resistance and electrochemical performance of the nickel-based cermet anodes for SOFCs.

  9. EFFECT OF FUEL IMPURITIES ON FUEL CELL PERFORMANCE AND DURABILITY

    SciTech Connect

    Colon-Mercado, H.

    2010-09-28

    A fuel cell is an electrochemical energy conversion device that produces electricity during the combination of hydrogen and oxygen to produce water. Proton exchange membranes fuel cells are favored for portable applications as well as stationary ones due to their high power density, low operating temperature, and low corrosion of components. In real life operation, the use of pure fuel and oxidant gases results in an impractical system. A more realistic and cost efficient approach is the use of air as an oxidant gas and hydrogen from hydrogen carriers (i.e., ammonia, hydrocarbons, hydrides). However, trace impurities arising from different hydrogen sources and production increases the degradation of the fuel cell. These impurities include carbon monoxide, ammonia, sulfur, hydrocarbons, and halogen compounds. The International Organization for Standardization (ISO) has set maximum limits for trace impurities in the hydrogen stream; however fuel cell data is needed to validate the assumption that at those levels the impurities will cause no degradation. This report summarizes the effect of selected contaminants tested at SRNL at ISO levels. Runs at ISO proposed concentration levels show that model hydrocarbon compound such as tetrahydrofuran can cause serious degradation. However, the degradation is only temporary as when the impurity is removed from the hydrogen stream the performance completely recovers. Other molecules at the ISO concentration levels such as ammonia don't show effects on the fuel cell performance. On the other hand carbon monoxide and perchloroethylene shows major degradation and the system can only be recovered by following recovery procedures.

  10. Effects of Operating Parameters on Measurements of Biochemical Oxygen Demand Using a Mediatorless Microbial Fuel Cell Biosensor

    PubMed Central

    Hsieh, Min-Chi; Cheng, Chiu-Yu; Liu, Man-Hai; Chung, Ying-Chien

    2015-01-01

    The conventional Biochemical Oxygen Demand (BOD) method takes five days to analyze samples. A microbial fuel cell (MFC) may be an alternate tool for rapid BOD determination in water. However, a MFC biosensor for continuous BOD measurements of water samples is still unavailable. In this study, a MFC biosensor inoculated with known mixed cultures was used to determine the BOD concentration. Effects of important parameters on establishing a calibration curve between the BOD concentration and output signal from the MFC were evaluated. The results indicate monosaccharides were good fuel, and methionine, phenylalanine, and ethanol were poor fuels for electricity generation by the MFC. Ions in the influent did not significantly affect the MFC performance. CN− in the influent could alleviate the effect of antagonistic electron acceptors on the MFC performance. The regression equation for BOD concentration and current density of the biosensor was y = 0.0145x + 0.3317. It was adopted to measure accurately and continuously the BOD concentration in actual water samples at an acceptable error margin. These results clearly show the developed MFC biosensor has great potential as an alternative BOD sensing device for online measurements of wastewater BOD. PMID:26729113

  11. Effects of Operating Parameters on Measurements of Biochemical Oxygen Demand Using a Mediatorless Microbial Fuel Cell Biosensor.

    PubMed

    Hsieh, Min-Chi; Cheng, Chiu-Yu; Liu, Man-Hai; Chung, Ying-Chien

    2015-12-28

    The conventional Biochemical Oxygen Demand (BOD) method takes five days to analyze samples. A microbial fuel cell (MFC) may be an alternate tool for rapid BOD determination in water. However, a MFC biosensor for continuous BOD measurements of water samples is still unavailable. In this study, a MFC biosensor inoculated with known mixed cultures was used to determine the BOD concentration. Effects of important parameters on establishing a calibration curve between the BOD concentration and output signal from the MFC were evaluated. The results indicate monosaccharides were good fuel, and methionine, phenylalanine, and ethanol were poor fuels for electricity generation by the MFC. Ions in the influent did not significantly affect the MFC performance. CN(-) in the influent could alleviate the effect of antagonistic electron acceptors on the MFC performance. The regression equation for BOD concentration and current density of the biosensor was y = 0.0145x + 0.3317. It was adopted to measure accurately and continuously the BOD concentration in actual water samples at an acceptable error margin. These results clearly show the developed MFC biosensor has great potential as an alternative BOD sensing device for online measurements of wastewater BOD.

  12. Molten carbonate fuel cells - Technology status

    NASA Astrophysics Data System (ADS)

    Pierce, R. D.

    The functional principles, components, operating conditions, and problems in prototype molten carbonate fuel cell plants are described. Centralized carbonate fuel cells consist of four subsystems: a coal gasifier and gas cleanup system, fuel cell stacks, heat removal and recovery system, and a power conditioner to convert dc to ac current. The fuel in the cells comprises hydrogen and carbon monoxide, and produces current by means of completion of an electrical circuit through transfer of carbonate ions through the electrolyte and electrons from cell to cell and eventually into the external circuit. Electrodes are porous sheets which provide sites for the electrochemical reaction and conduction paths for the reactants and products. The construction of LiAlO2-carbonate electrolyte structures is noted, and the electrolyte distribution and structures, the anodes, cathodes, separator plate, and operational problems are considered.

  13. Fuel cell electrode

    SciTech Connect

    Struthers, R. C.

    1985-03-05

    A flat, laminated fuel cell gas electrode arranged between and separating gas and liquid mediums in a fuel cell. The electrode includes a flat, perforated sheet metal support and electric conductor part with a rear surface disposed toward the gas medium, a flat, hydrophobic gas permeable membrane with a rear surface in contact with a front surface of said part, a flat liquid and gas permeable metallic current collector with a rear surface spaced from a front surface of said membrane and with a front surface disposed toward the liquid medium, a catalytic barrier structure of bonded together particulate catalytic material and metal conductor filaments by and in electric conducting contact with the collector and having a rear surface in contact with the front surface of the membrane and a plurality of spaced apart electric conducting fasteners engaged with and between said part and collector securing the parts of the electrode in assembled relationship and electrically connecting the current collector with said part.

  14. The effect of coal syngas containing HCl on the performance of solid oxide fuel cells: Investigations into the effect of operational temperature and HCl concentration

    NASA Astrophysics Data System (ADS)

    Trembly, J. P.; Gemmen, R. S.; Bayless, D. J.

    The performance of solid oxide fuel cells (SOFCs) using simulated coal-derived syngas, with and without hydrogen chloride (HCl), was studied. Electrolyte-supported SOFCs were tested potentiostatically at 0.7 V at 800 and 900 °C with simulated coal syngas containing 0, 20, and 160 ppm HCl. The results from the tests without HCl show good performance with little degradation over 100 h of operation. Both 20 and 160 ppm HCl were shown to cause performance losses in the SOFCs after injection into the system. Although the tests presented in this paper show that HCl does cause degradation to SOFC performance, the cell performance was recoverable upon the removal of HCl from the fuel. Also recent results from anticipated Integrated Gasification Combined Cycle IGCC warm/hot-gas-cleanup technologies suggest that HCl will be removed to levels that will not cause any significant performance losses in SOFCs.

  15. Fuel cell oxygen electrode

    DOEpatents

    Shanks, H.R.; Bevolo, A.J.; Danielson, G.C.; Weber, M.F.

    An oxygen electrode for a fuel cell utilizing an acid electrolyte has a substrate of an alkali metal tungsten bronze of the formula: A/sub x/WO/sub 3/ where A is an alkali metal and x is at least 0.2, which is covered with a thin layer of platinum tungsten bronze of the formula: Pt/sub y/WO/sub 3/ where y is at least 0.8.

  16. Fuel cell oxygen electrode

    DOEpatents

    Shanks, Howard R.; Bevolo, Albert J.; Danielson, Gordon C.; Weber, Michael F.

    1980-11-04

    An oxygen electrode for a fuel cell utilizing an acid electrolyte has a substrate of an alkali metal tungsten bronze of the formula: A.sub.x WO.sub.3 where A is an alkali metal and x is at least 0.2, which is covered with a thin layer of platinum tungsten bronze of the formula: Pt.sub.y WO.sub.3 where y is at least 0.8.

  17. Carbonate fuel cell matrix

    DOEpatents

    Farooque, Mohammad; Yuh, Chao-Yi

    1996-01-01

    A carbonate fuel cell matrix comprising support particles and crack attenuator particles which are made platelet in shape to increase the resistance of the matrix to through cracking. Also disclosed is a matrix having porous crack attenuator particles and a matrix whose crack attenuator particles have a thermal coefficient of expansion which is significantly different from that of the support particles, and a method of making platelet-shaped crack attenuator particles.

  18. Fuel Cell Stacks

    DTIC Science & Technology

    1975-04-01

    AD-A009 587 FUEL CELL STACKS Bernard S. Baker Energy Research Corporation Prepared for: Army Mobility Equipment Research and Development Center April... Mobility Equipment Research and Development Center Unclassified For- Belvoir, Virginia 22060 [15. DE.CLASSIFICATION/L.TWNOGRADING SCREOUJLE 16...the majority of effort has been directed at translating technoilogy for small comn- ponent manufacture on a laboratory scale into large size components

  19. Fuel cell current collector

    DOEpatents

    Katz, Murray; Bonk, Stanley P.; Maricle, Donald L.; Abrams, Martin

    1991-01-01

    A fuel cell has a current collector plate (22) located between an electrode (20) and a separate plate (25). The collector plate has a plurality of arches (26, 28) deformed from a single flat plate in a checkerboard pattern. The arches are of sufficient height (30) to provide sufficient reactant flow area. Each arch is formed with sufficient stiffness to accept compressive load and sufficient resiliently to distribute the load and maintain electrical contact.

  20. Carbonate fuel cell matrix

    DOEpatents

    Farooque, M.; Yuh, C.Y.

    1996-12-03

    A carbonate fuel cell matrix is described comprising support particles and crack attenuator particles which are made platelet in shape to increase the resistance of the matrix to through cracking. Also disclosed is a matrix having porous crack attenuator particles and a matrix whose crack attenuator particles have a thermal coefficient of expansion which is significantly different from that of the support particles, and a method of making platelet-shaped crack attenuator particles. 8 figs.

  1. Ambient pressure fuel cell system

    DOEpatents

    Wilson, Mahlon S.

    2000-01-01

    An ambient pressure fuel cell system is provided with a fuel cell stack formed from a plurality of fuel cells having membrane/electrode assemblies (MEAs) that are hydrated with liquid water and bipolar plates with anode and cathode sides for distributing hydrogen fuel gas and water to a first side of each one of the MEAs and air with reactant oxygen gas to a second side of each one of the MEAs. A pump supplies liquid water to the fuel cells. A recirculating system may be used to return unused hydrogen fuel gas to the stack. A near-ambient pressure blower blows air through the fuel cell stack in excess of reaction stoichiometric amounts to react with the hydrogen fuel gas.

  2. Local potential evolutions during proton exchange membrane fuel cell operation with dead-ended anode - Part II: Aging mitigation strategies based on water management and nitrogen crossover

    NASA Astrophysics Data System (ADS)

    Abbou, S.; Dillet, J.; Maranzana, G.; Didierjean, S.; Lottin, O.

    2017-02-01

    Proton exchange membrane (PEM) fuel cells operate with dead-ended anode in order to reduce system cost and complexity when compared with hydrogen re-circulation systems. In the first part of this work, we showed that localized fuel starvation events may occur, because of water and nitrogen accumulation in the anode side, which could be particularly damaging to the cell performance. To prevent these degradations, the anode compartment must be purged which may lead to an overall system efficiency decrease because of significant hydrogen waste. In the second part, we present several purge strategies in order to minimize both hydrogen waste and membrane-electrode assembly degradations during dead-ended anode operation. A linear segmented cell with reference electrodes was used to monitor simultaneously the current density distribution along the gas channel and the time evolution of local anode and cathode potentials. To asses MEA damages, Platinum ElectroChemical Surface Area (ECSA) and cell performance were periodically measured. The results showed that dead-end mode operation with an anode plate maintained at a temperature 5 °C hotter than the cathode plate limits water accumulation in the anode side, reducing significantly purge frequency (and thus hydrogen losses) as well as MEA damages. As nitrogen contribution to hydrogen starvation is predominant in this thermal configuration, we also tested a microleakage solution to discharge continuously most the nitrogen accumulating in the anode side while ensuring low hydrogen losses and minimum ECSA losses provided the right microleakage flow rate is chosen.

  3. An Overview of Stationary Fuel Cell Technology

    SciTech Connect

    DR Brown; R Jones

    1999-03-23

    Technology developments occurring in the past few years have resulted in the initial commercialization of phosphoric acid (PA) fuel cells. Ongoing research and development (R and D) promises further improvement in PA fuel cell technology, as well as the development of proton exchange membrane (PEM), molten carbonate (MC), and solid oxide (SO) fuel cell technologies. In the long run, this collection of fuel cell options will be able to serve a wide range of electric power and cogeneration applications. A fuel cell converts the chemical energy of a fuel into electrical energy without the use of a thermal cycle or rotating equipment. In contrast, most electrical generating devices (e.g., steam and gas turbine cycles, reciprocating engines) first convert chemical energy into thermal energy and then mechanical energy before finally generating electricity. Like a battery, a fuel cell is an electrochemical device, but there are important differences. Batteries store chemical energy and convert it into electrical energy on demand, until the chemical energy has been depleted. Depleted secondary batteries may be recharged by applying an external power source, while depleted primary batteries must be replaced. Fuel cells, on the other hand, will operate continuously, as long as they are externally supplied with a fuel and an oxidant.

  4. 3-Dimensional Computational Fluid Dynamics Modeling of Solid Oxide Fuel Cell Using Different Fuels

    DTIC Science & Technology

    2011-01-01

    major types of fuel cells in practice are listed below: Polymer Electrolyte Membrane Fuel Cell ( PEMFC ) Alkaline Fuel cell (AFC) Phosphoric Acid...Material Operating Temperature (oC) Efficiency (%) PEMFC H2, Methanol, Formic Acid Hydrated Organic Polymer < 90 40-50 AFC Pure H2 Aqueous

  5. Hydrogen-fueled polymer electrolyte fuel cell systems for transportation.

    SciTech Connect

    Ahluwalia, R.; Doss, E.D.; Kumar, R.

    1998-10-19

    The performance of a polymer electrolyte fuel cell (PEFC) system that is fueled directly by hydrogen has been evaluated for transportation vehicles. The performance was simulated using a systems analysis code and a vehicle analysis code. The results indicate that, at the design point for a 50-kW PEFC system, the system efficiency is above 50%. The efficiency improves at partial load and approaches 60% at 40% load, as the fuel cell operating point moves to lower current densities on the voltage-current characteristic curve. At much lower loads, the system efficiency drops because of the deterioration in the performance of the compressor, expander, and, eventually, the fuel cell. The results also indicate that the PEFC system can start rapidly from ambient temperatures. Depending on the specific weight of the fuel cell (1.6 kg/kW in this case), the system takes up to 180s to reach its design operating conditions. The PEFC system has been evaluated for three mid-size vehicles: the 1995 Chrysler Sedan, the near-term Ford AIV (Aluminum Intensive Vehicle) Sable, and the future P2000 vehicle. The results show that the PEFC system can meet the demands of the Federal Urban Driving Schedule and the Highway driving cycles, for both warm and cold start-up conditions. The results also indicate that the P2000 vehicle can meet the fuel economy goal of 80 miles per gallon of gasoline (equivalent).

  6. Cathode for molten carbonate fuel cell

    DOEpatents

    Kaun, Thomas D.; Mrazek, Franklin C.

    1990-01-01

    A porous sintered cathode for a molten carbonate fuel cell and method of making same, the cathode including a skeletal structure of a first electronically conductive material slightly soluble in the electrolyte present in the molten carbonate fuel cell covered by fine particles of a second material of possibly lesser electronic conductivity insoluble in the electrolyte present in the molten carbonate fuel cell, the cathode having a porosity in the range of from about 60% to about 70% at steady-state cell operating conditions consisting of both macro-pores and micro-pores.

  7. Cathode for molten carbonate fuel cell

    DOEpatents

    Kaun, Thomas D.; Mrazek, Franklin C.

    1990-01-01

    A porous sintered cathode for a molten carbonate fuel cell and method of making same, the cathode including a skeletal structure of a first electronically conductive material slightly soluble in the electrolyte present in the molten carbonate fuel cell covered by fine particles of a second material of possibly lesser electronic conductivity insoluble in the electrolyte present in the molten carbonate fuel cell, the cathode having a porosity in the range of from about 60% to about 70% at steady-state cell operating conditions consisting of both macro-pores and micro-pores.

  8. FUEL CELL MANPACK POWER SOURCE.

    DTIC Science & Technology

    battery provides required power density and instantly available power while the fuel cell efficiently converts a primary fuel to electrical power at a...field supply, afford an extremely high energy density making the hybrid fuel cell system competitive on cost per kilowatt hour with standard military zinc-carbon primary batteries. (Author)

  9. Analysis of power and energy for fuel cell systems

    NASA Astrophysics Data System (ADS)

    Kinoshita, Kim; R. Landgrebe, Albert

    The relationship between power and energy for a fuel cell system consisting of a fuel cell stack and reactant storage subsystem, and operating at constant power or variable power, was analyzed. The characteristic parameters of the fuel cell stack and the reactant subsystem are considered to be independent variables, which are functions of the power and energy of the fuel cell cystem, respectively. Mathematical expressions were derived for determining the minimum weight of the fuel cell system when the cells operate at constant power and the cell voltage varies linearly with the current density. The relationship between the weight of a fuel cell system and variable power levels was also determined. These mathematical models were used to analyze the experimental results reported in the literature for an alkaline fuel cell and a polymer electrolyte fuel cell.

  10. Bioelectricity generation in an integrated system combining microbial fuel cell and tubular membrane reactor: effects of operation parameters performing a microbial fuel cell-based biosensor for tubular membrane bioreactor.

    PubMed

    Wang, Jie; Zheng, Yawen; Jia, Hui; Zhang, Hongwei

    2014-10-01

    A bio-cathode microbial fuel cell (MFC) with tubular membrane was integrated to construct a microbial fuel cell-tubular membrane bioreactor (MFC-TMBR) system, in which the bio-cathode MFC was developed as a biosensor for COD real-time monitoring in TMBR and the performance was analyzed in terms of its current variation caused by operation parameters. With a constant anode potential, the effect of HRT demonstrated that higher rate of mass transport increased the response of the system. The system was further explored an inverse relationship between TMP and current peak by using EPS concentration under the different MLSS concentration. The sensor output had a linear relationship with COD up to 1000mg/L (regression coefficient, R(2)=0.97) and MLSS (regression coefficient, R(2)=0.94). The simple and compact bio-cathode MFC biosensor for TMBR using MFC-TMBR integrated system showed promising potential for direct and economical COD online monitoring, and provided an opportunity to widen the application of MFC-based biosensor.

  11. Solid Acid Fuel Cell Stack for APU Applications

    SciTech Connect

    Duong, Hau H.

    2011-04-15

    Solid acid fuel cell technology affords the opportunity to operate at the 200-300 degree centigrade regime that would allow for more fuel flexibility, compared to polymer electrode membrane fuel cell, while avoiding the relatively more expensive and complex system components required by solid oxide fuel cell. This project addresses many factors such as MEA size scalability, fuel robustness, stability, etc., that are essential for successful commercialization of the technology.

  12. A niobium and tantalum co-doped perovskite cathode for solid oxide fuel cells operating below 500 °C.

    PubMed

    Li, Mengran; Zhao, Mingwen; Li, Feng; Zhou, Wei; Peterson, Vanessa K; Xu, Xiaoyong; Shao, Zongping; Gentle, Ian; Zhu, Zhonghua

    2017-01-03

    The slow activity of cathode materials is one of the most significant barriers to realizing the operation of solid oxide fuel cells below 500 °C. Here we report a niobium and tantalum co-substituted perovskite SrCo0.8Nb0.1Ta0.1O3-δ as a cathode, which exhibits high electroactivity. This cathode has an area-specific polarization resistance as low as ∼0.16 and ∼0.68 Ω cm(2) in a symmetrical cell and peak power densities of 1.2 and 0.7 W cm(-2) in a Gd0.1Ce0.9O1.95-based anode-supported fuel cell at 500 and 450 °C, respectively. The high performance is attributed to an optimal balance of oxygen vacancies, ionic mobility and surface electron transfer as promoted by the synergistic effects of the niobium and tantalum. This work also points to an effective strategy in the design of cathodes for low-temperature solid oxide fuel cells.

  13. A niobium and tantalum co-doped perovskite cathode for solid oxide fuel cells operating below 500 °C

    PubMed Central

    Li, Mengran; Zhao, Mingwen; Li, Feng; Zhou, Wei; Peterson, Vanessa K.; Xu, Xiaoyong; Shao, Zongping; Gentle, Ian; Zhu, Zhonghua

    2017-01-01

    The slow activity of cathode materials is one of the most significant barriers to realizing the operation of solid oxide fuel cells below 500 °C. Here we report a niobium and tantalum co-substituted perovskite SrCo0.8Nb0.1Ta0.1O3−δ as a cathode, which exhibits high electroactivity. This cathode has an area-specific polarization resistance as low as ∼0.16 and ∼0.68 Ω cm2 in a symmetrical cell and peak power densities of 1.2 and 0.7 W cm−2 in a Gd0.1Ce0.9O1.95-based anode-supported fuel cell at 500 and 450 °C, respectively. The high performance is attributed to an optimal balance of oxygen vacancies, ionic mobility and surface electron transfer as promoted by the synergistic effects of the niobium and tantalum. This work also points to an effective strategy in the design of cathodes for low-temperature solid oxide fuel cells. PMID:28045088

  14. Carbonate fuel cell matrix strengthening

    SciTech Connect

    Yuh, C.Y.; Haung, C.M.; Johnsen, R.

    1995-12-31

    The present baseline electrolyte matrix is a porous ceramic powder bed impregnated with alkali carbonate electrolyte. The matrix provides both ionic conduction and gas sealing. During fuel cell stack operation, the matrix experiences both mechanical and thermal stresses. Different mechanical characteristics of active and wet seal areas generate stress. Thermal stress is generated by nonuniform temperature distribution and thermal cycling. A carbonate fuel cell generally may experience planned and unplanned thermal cycles between 650 C and room temperature during its 40,000h life. During the cycling, the electrolyte matrix expands and contracts at a different rate from other cell components. Furthermore, the change in electrolyte volume associated with freezing/melting may generate additional thermal stress. Strengthening of the matrix may be beneficial for longer-term stability of the carbonate fuel cell with respect to repeated thermal cycling. Several promising strengtheners with improved chemical and mechanical stabilities were identified. Fibers provide the highest strengthening effect, followed by particulates. Matrix fabrication technique was successfully modified for uniformly incorporating the advanced strengtheners, maintaining the desired aspect ratio. Enhanced gas sealing demonstrated using the advanced matrices.

  15. Fuel cell system with interconnect

    DOEpatents

    Liu, Zhien; Goettler, Richard; Delaforce, Philip Mark

    2016-03-08

    The present invention includes a fuel cell system having an interconnect that reduces or eliminates diffusion (leakage) of fuel and oxidant by providing an increased densification, by forming the interconnect as a ceramic/metal composite.

  16. Polymer electrolyte fuel cells

    NASA Astrophysics Data System (ADS)

    Gottesfeld, S.

    The recent increase in attention to polymer electrolyte fuel cells (PEFC's) is the result of significant technical advances in this technology and the initiation of some projects for the demonstration of complete PEFC-based power system in a bus or in a passenger car. A PEFC powered vehicle has the potential for zero emission, high energy conversion efficiency and extended range compared to present day battery powered EV's. This paper describes recent achievements in R&D on PEFC's. The major thrust areas have been: (1) demonstration of membrane/electrode assemblies with stable high performance in life tests lasting 4000 hours, employing ultra-low Pt loadings corresponding to only 1/2 oz of Pt for the complete power source of a passenger car; (2) effective remedies for the high sensitivity of the Pt electrocatalyst to impurities in the fuel feed stream; and (3) comprehensive evaluation of the physicochemical properties of membrane and electrodes in the PEFC, clarifying the water management issues and enabling effective codes and diagnostics for this fuel cell.

  17. Fuel cell tubes and method of making same

    DOEpatents

    Borglum, Brian P.

    1999-11-30

    A method of manufacturing porous ceramic tubes for fuel cells with improved properties and higher manufacturing yield is disclosed. The method involves extruding a closed end fuel cell tube, such as an air electrode of a solid oxide fuel cell, in which the closed end also functions as the sintering support. The resultant fuel cell tube has a superior porosity distribution which allows improved diffusion of oxygen at the closed end of the tube during operation of the fuel cell. Because this region has the highest current density, performance enhancement and improved reliability of the fuel cell tube result. Furthermore, the higher manufacturing yield associated with the present method decreases the overall fuel cell cost. A method of manufacturing porous ceramic tubes for fuel cells with improved properties and higher manufacturing yield is disclosed. The method involves extruding a closed end fuel cell tube, such as an air electrode of a solid oxide fuel cell, in which the closed end also functions as the sintering support. The resultant fuel cell tube has a superior porosity distribution which allows improved diffusion of oxygen at the closed end of the tube during operation of the fuel cell. Because this region has the highest current density, performance enhancement and improved reliability of the fuel cell tube result. Furthermore, the higher manufacturing yield associated with the present method decreases the overall fuel cell cost.

  18. MOLTEN CARBONATE FUEL CELL PRODUCT DESIGN IMPROVEMENT

    SciTech Connect

    H.C. Maru; M. Farooque

    2004-08-01

    The ongoing program is designed to advance the carbonate fuel cell technology from full-size proof-of-concept field test to the commercial design. DOE has been funding Direct FuelCell{reg_sign} (DFC{reg_sign}) development at FuelCell Energy, Inc. (FCE) for stationary power plant applications. The program efforts are focused on technology and system optimization for cost reduction, leading to commercial design development and prototype system field trials. FCE, Danbury, CT, is a world-recognized leader for the development and commercialization of high efficiency fuel cells that can generate clean electricity at power stations, or at distributed locations near the customers such as hospitals, schools, universities, hotels and other commercial and industrial applications. FCE has designed three different fuel cell power plant models (DFC300A, DFC1500 and DFC3000). FCE's power plants are based on its patented DFC{reg_sign} technology, where the fuel is directly fed to the fuel cell and hydrogen is generated internally. These power plants offer significant advantages compared to the existing power generation technologies--higher fuel efficiency, significantly lower emissions, quieter operation, flexible siting and permitting requirements, scalability and potentially lower operating costs. Also, the exhaust heat by-product can be used for cogeneration applications such as high-pressure steam, district heating and air conditioning. Several FCE sub-megawatt power plants are currently operating in Europe, Japan and the US. Because hydrogen is generated directly within the fuel cell module from readily available fuels such as natural gas and waste water treatment gas, DFC power plants are ready today and do not require the creation of a hydrogen infrastructure. Product improvement progress made during the reporting period in the areas of technology, manufacturing processes, cost reduction and balance of plant equipment designs is discussed in this report.

  19. Near-ambient solid polymer fuel cell

    NASA Technical Reports Server (NTRS)

    Holleck, G. L.

    1993-01-01

    Fuel cells are extremely attractive for extraterrestrial and terrestrial applications because of their high energy conversion efficiency without noise or environmental pollution. Among the various fuel cell systems the advanced polymer electrolyte membrane fuel cells based on sulfonated fluoropolymers (e.g., Nafion) are particularly attractive because they are fairly rugged, solid state, quite conductive, of good chemical and thermal stability and show good oxygen reduction kinetics due to the low specific adsorption of the electrolyte on the platinum catalyst. The objective of this program is to develop a solid polymer fuel cell which can efficiently operate at near ambient temperatures without ancillary components for humidification and/or pressurization of the fuel or oxidant gases. During the Phase 1 effort we fabricated novel integral electrode-membrane structures where the dispersed platinum catalyst is precipitated within the Nafion ionomer. This resulted in electrode-membrane units without interfacial barriers permitting unhindered water diffusion from cathode to anode. The integral electrode-membrane structures were tested as fuel cells operating on H2 and O2 or air at 1 to 2 atm and 10 to 50 C without gas humidification. We demonstrated that cells with completely dry membranes could be self started at room temperature and subsequently operated on dry gas for extended time. Typical room temperature low pressure operation with unoptimized electrodes yielded 100 mA/cm(exp 2) at 0.5V and maximum currents over 300 mA/cm(exp 2) with low platinum loadings. Our results clearly demonstrate that operation of proton exchange membrane fuel cells at ambient conditions is feasible. Optimization of the electrode-membrane structure is necessary to assess the full performance potential but we expect significant gains in weight and volume power density for the system. The reduced complexity will make fuel cells also attractive for smaller and portable power supplies and as

  20. MOLTEN CARBONATE FUEL CELL PRODUCT DESIGN IMPROVEMENT

    SciTech Connect

    H.C. Maru; M. Farooque

    2002-02-01

    The carbonate fuel cell promises highly efficient, cost-effective and environmentally superior power generation from pipeline natural gas, coal gas, biogas, and other gaseous and liquid fuels. FuelCell Energy, Inc. has been engaged in the development of this unique technology, focusing on the development of the Direct Fuel Cell (DFC{reg_sign}). The DFC{reg_sign} design incorporates the unique internal reforming feature which allows utilization of a hydrocarbon fuel directly in the fuel cell without requiring any external reforming reactor and associated heat exchange equipment. This approach upgrades waste heat to chemical energy and thereby contributes to a higher overall conversion efficiency of fuel energy to electricity with low levels of environmental emissions. Among the internal reforming options, FuelCell Energy has selected the Indirect Internal Reforming (IIR)--Direct Internal Reforming (DIR) combination as its baseline design. The IIR-DIR combination allows reforming control (and thus cooling) over the entire cell area. This results in uniform cell temperature. In the IIR-DIR stack, a reforming unit (RU) is placed in between a group of fuel cells. The hydrocarbon fuel is first fed into the RU where it is reformed partially to hydrogen and carbon monoxide fuel using heat produced by the fuel cell electrochemical reactions. The reformed gases are then fed to the DIR chamber, where the residual fuel is reformed simultaneously with the electrochemical fuel cell reactions. FuelCell Energy plans to offer commercial DFC power plants in various sizes, focusing on the subMW as well as the MW-scale units. The plan is to offer standardized, packaged DFC power plants operating on natural gas or other hydrocarbon-containing fuels for commercial sale. The power plant design will include a diesel fuel processing option to allow dual fuel applications. These power plants, which can be shop-fabricated and sited near the user, are ideally suited for distributed power

  1. Fuel cell systems program plan: Fiscal year 1988

    NASA Astrophysics Data System (ADS)

    1988-05-01

    The DOE fuel cell program supports high-risk, high-payoff technology development. This provides industry with the capability to develop and apply fuel cell systems that use conventional and alternative hydrocarbon fuels. The principal DOE fuel cell program goal is to develop cost effective, efficient, and environmentally benign fuel cell systems which will operate on coal-based fuels (and dual fuels: coal and gas) in multiple end use sectors. In the near-term, and as an interim step in achieving this goal, distillate fuel and natural fuel cell system technologies will also be developed. This interim step is a logical progression to the more complex coal-fueled systems and provides a marketable gas-fueled technology. The specific near- to mid-term (mid-1990s) objectives are to develop the key fuel cell technology for phosphoric acid, molten carbonate, and solid oxide fuel cell systems, and to evaluate and conduct research on more advanced fuel cell concepts that would further improve technical and economic performance. Advanced fuel cell concepts may in the long-term (post 2000) offer potential for use in additional applications such as in the transportation and residential sectors. In these applications oil could be displaced by fuel cell systems using fuels derived from coal.

  2. DOE perspective on fuel cells in transportation

    SciTech Connect

    Kost, R.

    1996-04-01

    Fuel cells are one of the most promising technologies for meeting the rapidly growing demand for transportation services while minimizing adverse energy and environmental impacts. This paper reviews the benefits of introducing fuel cells into the transportation sector; in addition to dramatically reduced vehicle emissions, fuel cells offer the flexibility than use petroleum-based or alternative fuels, have significantly greater energy efficiency than internal combustion engines, and greatly reduce noise levels during operation. The rationale leading to the emphasis on proton-exchange-membrane fuel cells for transportation applications is reviewed as are the development issues requiring resolution to achieve adequate performance, packaging, and cost for use in automobiles. Technical targets for power density, specific power, platinum loading on the electrodes, cost, and other factors that become increasingly more demanding over time have been established. Fuel choice issues and pathways to reduced costs and to a renewable energy future are explored. One such path initially introduces fuel cell vehicles using reformed gasoline while-on-board hydrogen storage technology is developed to the point of allowing adequate range (350 miles) and refueling convenience. This scenario also allows time for renewable hydrogen production technologies and the required supply infrastructure to develop. Finally, the DOE Fuel Cells in Transportation program is described. The program, whose goal is to establish the technology for fuel cell vehicles as rapidly as possible, is being implemented by means of the United States Fuel Cell Alliance, a Government-industry alliance that includes Detroit`s Big Three automakers, fuel cell and other component suppliers, the national laboratories, and universities.

  3. Sealant materials for solid oxide fuel cells

    SciTech Connect

    Krumpelt, M.

    1995-08-01

    The objective of this work is to complete the development of soft glass-ceramic sealants for the solid oxide fuel cell (SOFC). Among other requirements, the materials must soften at the operation temperature of the fuel cell (600-1000{degrees}C) to relieve stresses between stack components, and their thermal expansions must be tailored to match those of the stack materials. Specific objectives included addressing the needs of industrial fuel cell developers, based on their evaluation of samples we supply, as well as working with commercial glass producers to achieve scaled-up production of the materials without changing their properties.

  4. Fuel Cells on Bio-Gas (Presentation)

    SciTech Connect

    Remick, R. J.

    2009-03-04

    The conclusions of this presentation are: (1) Fuel cells operating on bio-gas offer a pathway to renewable electricity generation; (2) With federal incentives of $3,500/kW or 30% of the project costs, reasonable payback periods of less than five years can be achieved; (3) Tri-generation of electricity, heat, and hydrogen offers an alternative route to solving the H{sub 2} infrastructure problem facing fuel cell vehicle deployment; and (4) DOE will be promoting bio-gas fuel cells in the future under its Market Transformation Programs.

  5. Electrochemical cell operation and system

    DOEpatents

    Maru, Hansraj C.

    1980-03-11

    Thermal control in fuel cell operation is affected through sensible heat of process gas by providing common input manifolding of the cell gas flow passage in communication with the cell electrolyte and an additional gas flow passage which is isolated from the cell electrolyte and in thermal communication with a heat-generating surface of the cell. Flow level in the cell gas flow passage is selected based on desired output electrical energy and flow level in the additional gas flow passage is selected in accordance with desired cell operating temperature.

  6. Advances in direct oxidation methanol fuel cells

    NASA Technical Reports Server (NTRS)

    Surampudi, S.; Narayanan, S. R.; Vamos, E.; Frank, H.; Halpert, G.; Laconti, Anthony B.; Kosek, J.; Prakash, G. K. Surya; Olah, G. A.

    1993-01-01

    Fuel cells that can operate directly on fuels such as methanol are attractive for low to medium power applications in view of their low weight and volume relative to other power sources. A liquid feed direct methanol fuel cell has been developed based on a proton exchange membrane electrolyte and Pt/Ru and Pt catalyzed fuel and air/O2 electrodes, respectively. The cell has been shown to deliver significant power outputs at temperatures of 60 to 90 C. The cell voltage is near 0.5 V at 300 mA/cm(exp 2) current density and an operating temperature of 90 C. A deterrent to performance appears to be methanol crossover through the membrane to the oxygen electrode. Further improvements in performance appear possible by minimizing the methanol crossover rate.

  7. Fuel cell elements with improved water handling capacity

    NASA Technical Reports Server (NTRS)

    Kindler, Andrew (Inventor); Lee, Albany (Inventor)

    2001-01-01

    New fuel cell components for use in liquid feed fuel cell systems are provided. The components include biplates and endplates, having a hydrophilic surface and allow high efficiency operation. Conductive elements and a wicking device also form a part of the fuel cell components of the invention.

  8. Fuel Cell Technology Status Analysis Project: Partnership Opportunities (Fact Sheet)

    SciTech Connect

    Not Available

    2013-01-01

    This fact sheet describes opportunities for leading fuel cell industry partners from the United States and abroad to participate in an objective and credible fuel cell technology performance and durability analysis by sharing their raw fuel cell test data related to operations, maintenance, safety, and cost with the National Renewable Energy Laboratory via the Hydrogen Secure Data Center.

  9. Fuel cell having electrolyte

    DOEpatents

    Wright, Maynard K.

    1989-01-01

    A fuel cell having an electrolyte control volume includes a pair of porous opposed electrodes. A maxtrix is positioned between the pair of electrodes for containing an electrolyte. A first layer of backing paper is positioned adjacent to one of the electrodes. A portion of the paper is substantially previous to the acceptance of the electrolyte so as to absorb electrolyte when there is an excess in the matrix and to desorb electrolyte when there is a shortage in the matrix. A second layer of backing paper is positioned adjacent to the first layer of paper and is substantially impervious to the acceptance of electrolyte.

  10. Carbonate fuel cell anodes

    DOEpatents

    Donado, R.A.; Hrdina, K.E.; Remick, R.J.

    1993-04-27

    A molten alkali metal carbonates fuel cell porous anode of lithium ferrite and a metal or metal alloy of nickel, cobalt, nickel/iron, cobalt/iron, nickel/iron/aluminum, cobalt/iron/aluminum and mixtures thereof wherein the total iron content including ferrite and iron of the composite is about 25 to about 80 percent, based upon the total anode, provided aluminum when present is less than about 5 weight percent of the anode. A process is described for production of the lithium ferrite containing anode by slipcasting.

  11. Carbonate fuel cell anodes

    DOEpatents

    Donado, Rafael A.; Hrdina, Kenneth E.; Remick, Robert J.

    1993-01-01

    A molten alkali metal carbonates fuel cell porous anode of lithium ferrite and a metal or metal alloy of nickel, cobalt, nickel/iron, cobalt/iron, nickel/iron/aluminum, cobalt/iron/aluminum and mixtures thereof wherein the total iron content including ferrite and iron of the composite is about 25 to about 80 percent, based upon the total anode, provided aluminum when present is less than about 5 weight percent of the anode. A process for production of the lithium ferrite containing anode by slipcasting.

  12. Fuel cell systems for personal and portable power applications

    SciTech Connect

    Fateen, S. A.

    2001-01-01

    Fuel cells are devices that electrochemically convert fuel, usually hydrogen gas, to directly produce electricity. Fuel cells were initially developed for use in the space program to provide electricity and drinking water for astronauts. Fuel cells are under development for use in the automobile industry to power cars and buses with the advantage of lower emissions and higher efficiency than internal combustion engines. Fuel cells also have great potential to be used in portable consumer products like cellular phones and laptop computers, as well as military applications. In fact, any products that use batteries can be powered by fuel cells. In this project, we examine fuel cell system trade-offs between fuel cell type and energy storage/hydrogen production for portable power generation. The types of fuel cells being examined include stored hydrogen PEM (polymer electrolyte), direct methanol fuel cells (DMFC) and indirect methanol fuel cells, where methanol is reformed producing hydrogen. These fuel cells systems can operate at or near ambient conditions, which make them potentially optimal for use in manned personal power applications. The expected power production for these systems is in the range of milliwatts to 500 watts of electrical power for either personal or soldier field use. The fuel cell system trade-offs examine hydrogen storage by metal hydrides, carbon nanotubes, and compressed hydrogen tanks. We examine the weights each system, volume, fuel storage, system costs, system peripherals, power output, and fuel cell feasibility in portable devices.

  13. Pattern recognition monitoring of PEM fuel cell

    DOEpatents

    Meltser, M.A.

    1999-08-31

    The CO-concentration in the H{sub 2} feed stream to a PEM fuel cell stack is monitored by measuring current and voltage behavior patterns from an auxiliary cell attached to the end of the stack. The auxiliary cell is connected to the same oxygen and hydrogen feed manifolds that supply the stack, and discharges through a constant load. Pattern recognition software compares the current and voltage patterns from the auxiliary cell to current and voltage signature determined from a reference cell similar to the auxiliary cell and operated under controlled conditions over a wide range of CO-concentrations in the H{sub 2} fuel stream. 4 figs.

  14. Pattern recognition monitoring of PEM fuel cell

    DOEpatents

    Meltser, Mark Alexander

    1999-01-01

    The CO-concentration in the H.sub.2 feed stream to a PEM fuel cell stack is monitored by measuring current and voltage behavior patterns from an auxiliary cell attached to the end of the stack. The auxiliary cell is connected to the same oxygen and hydrogen feed manifolds that supply the stack, and discharges through a constant load. Pattern recognition software compares the current and voltage patterns from the auxiliary cell to current and voltage signature determined from a reference cell similar to the auxiliary cell and operated under controlled conditions over a wide range of CO-concentrations in the H.sub.2 fuel stream.

  15. Hybrid Fuel Cell Technology Overview

    SciTech Connect

    None available

    2001-05-31

    For the purpose of this STI product and unless otherwise stated, hybrid fuel cell systems are power generation systems in which a high temperature fuel cell is combined with another power generating technology. The resulting system exhibits a synergism in which the combination performs with an efficiency far greater than can be provided by either system alone. Hybrid fuel cell designs under development include fuel cell with gas turbine, fuel cell with reciprocating (piston) engine, and designs that combine different fuel cell technologies. Hybrid systems have been extensively analyzed and studied over the past five years by the Department of Energy (DOE), industry, and others. These efforts have revealed that this combination is capable of providing remarkably high efficiencies. This attribute, combined with an inherent low level of pollutant emission, suggests that hybrid systems are likely to serve as the next generation of advanced power generation systems.

  16. Carbonate fuel cells: Milliwatts to megawatts

    NASA Astrophysics Data System (ADS)

    Farooque, M.; Maru, H. C.

    The carbonate fuel cell power plant is an emerging high efficiency, ultra-clean power generator utilizing a variety of gaseous, liquid, and solid carbonaceous fuels for commercial and industrial applications. The primary mover of this generator is a carbonate fuel cell. The fuel cell uses alkali metal carbonate mixtures as electrolyte and operates at ∼650 °C. Corrosion of the cell hardware and stability of the ceramic components have been important design considerations in the early stages of development. The material and electrolyte choices are founded on extensive fundamental research carried out around the world in the 60s and early 70s. The cell components were developed in the late 1970s and early 1980s. The present day carbonate fuel cell construction employs commonly available stainless steels. The electrodes are based on nickel and well-established manufacturing processes. Manufacturing process development, scale-up, stack tests, and pilot system tests dominated throughout the 1990s. Commercial product development efforts began in late 1990s leading to prototype field tests beginning in the current decade leading to commercial customer applications. Cost reduction has been an integral part of the product effort. Cost-competitive product designs have evolved as a result. Approximately half a dozen teams around the world are pursuing carbonate fuel cell product development. The power plant development efforts to date have mainly focused on several hundred kW (submegawatt) to megawatt-class plants. Almost 40 submegawatt units have been operating at customer sites in the US, Europe, and Asia. Several of these units are operating on renewable bio-fuels. A 1 MW unit is operating on the digester gas from a municipal wastewater treatment plant in Seattle, Washington (US). Presently, there are a total of approximately 10 MW capacity carbonate fuel cell power plants installed around the world. Carbonate fuel cell products are also being developed to operate on

  17. Fuel cell gas management system

    DOEpatents

    DuBose, Ronald Arthur

    2000-01-11

    A fuel cell gas management system including a cathode humidification system for transferring latent and sensible heat from an exhaust stream to the cathode inlet stream of the fuel cell; an anode humidity retention system for maintaining the total enthalpy of the anode stream exiting the fuel cell equal to the total enthalpy of the anode inlet stream; and a cooling water management system having segregated deionized water and cooling water loops interconnected by means of a brazed plate heat exchanger.

  18. Fuel cell design and assembly

    DOEpatents

    Myerhoff, Alfred

    1984-01-01

    The present invention is directed to a novel bipolar cooling plate, fuel cell design and method of assembly of fuel cells. The bipolar cooling plate used in the fuel cell design and method of assembly has discrete opposite edge and means carried by the plate defining a plurality of channels extending along the surface of the plate toward the opposite edges. At least one edge of the channels terminates short of the edge of the plate defining a recess for receiving a fastener.

  19. Improved electrolytes for fuel cells

    SciTech Connect

    Gard, G.L.; Roe, D.K.

    1991-06-01

    Present day fuel cells based upon hydrogen and oxygen have limited performance due to the use of phosphoric acid as an electrolyte. Improved performance is desirable in electrolyte conductivity, electrolyte management, oxygen solubility, and the kinetics of the reduction of oxygen. Attention has turned to fluorosulfonic acids as additives or substitute electrolytes to improve fuel cell performance. The purpose of this project is to synthesize and electrochemically evaluate new fluorosulfonic acids as superior alternatives to phosphoric acid in fuel cells. (VC)

  20. Polymer electrolyte fuel cells: a review of recent developments

    NASA Astrophysics Data System (ADS)

    Prater, Keith B.

    The very high power density available from proton-exchange membrane (PEM) fuel cells combined with the potential for very low cost suggests the PEM fuel cell as the most probable power plant for the next generation, non-polluting automobile engine. The demonstrated capability of the PEM fuel cell to produce power from avilable hydrocarbon fuels opens the possibility of reliable, efficient, power generation located near the user. This review summarizes the operating principles of the fuel cell stack and power systems, describes the current status of the technology, focusing on recent developments, and discusses the technical challenges and commercial prospectis for this fuel cell technology.

  1. Fuel cell system with interconnect

    DOEpatents

    Liu, Zhien; Goettler, Richard

    2016-12-20

    The present invention includes an integrated planar, series connected fuel cell system having electrochemical cells electrically connected via interconnects, wherein the anodes of the electrochemical cells are protected against Ni loss and migration via an engineered porous anode barrier layer.

  2. Data Collection & Analysis for ARRA Fuel Cell Projects (Presentation)

    SciTech Connect

    Kurtz, J.; Ramsden, T.; Wipke, K.; Sprik, S.

    2009-08-21

    The data analysis objectives are: (1) Independent assessment of technology, focused on fuel cell system and hydrogen infrastructure:performance, operation, and safety; (2) Leverage data processing and analysis capabilities from the fuel cell vehicle Learning Demonstration project and DoD Forklift Demo; (3) Establish a baseline of real-world fuel cell operation and maintenance data and identify technical/market barriers; (4) Support market growth of fuel cell technologies by reporting on technology features relevant to the business case; and (5) Report on technology to fuel cell and hydrogen communities and stakeholders.

  3. Materials issues in solid oxide fuel cell systems

    SciTech Connect

    Ziomek-Moroz, M.

    2007-03-02

    Hydrogen is the main fuel for all types of fuel cells except direct methanol fuel cells. Hydrogen can be generated from all manner of fossil fuels, including coal, natural gas, diesel, gasoline, other hydrocarbons, and oxygenates (e.g., methanol, ethanol, butanol, etc.). The presence of carbon oxides in the fuel can cause significant performance problems resulting in decreasing the cell performance of fuel cells, including solid oxide fuel cells (SOFC). In the SOFC, the high (800-1000°C) operating temperature yields advantages (e.g., internal fuel reforming) and disadvantages (e.g., material selection and degradation problems). Significant progress in reducing the operating temperature of the SOFC below ~800 ºC may allow less expensive metallic materials to be used for interconnects. This presentation provides insight on the material performance of ferritic steels in fuels containing carbon oxides and seeks to quantify the extent of possible degradation due to carbon species in the gas stream.

  4. Solid polymer MEMS-based fuel cells

    DOEpatents

    Jankowski, Alan F.; Morse, Jeffrey D.

    2008-04-22

    A micro-electro-mechanical systems (MEMS) based thin-film fuel cells for electrical power applications. The MEMS-based fuel cell may be of a solid oxide type (SOFC), a solid polymer type (SPFC), or a proton exchange membrane type (PEMFC), and each fuel cell basically consists of an anode and a cathode separated by an electrolyte layer. The electrolyte layer can consist of either a solid oxide or solid polymer material, or proton exchange membrane electrolyte materials may be used. Additionally catalyst layers can also separate the electrodes (cathode and anode) from the electrolyte. Gas manifolds are utilized to transport the fuel and oxidant to each cell and provide a path for exhaust gases. The electrical current generated from each cell is drawn away with an interconnect and support structure integrated with the gas manifold. The fuel cells utilize integrated resistive heaters for efficient heating of the materials. By combining MEMS technology with thin-film deposition technology, thin-film fuel cells having microflow channels and full-integrated circuitry can be produced that will lower the operating temperature an will yield an order of magnitude greater power density than the currently known fuel cells.

  5. Solid oxide MEMS-based fuel cells

    DOEpatents

    Jankowksi, Alan F.; Morse, Jeffrey D.

    2007-03-13

    A micro-electro-mechanical systems (MEMS) based thin-film fuel cells for electrical power applications. The MEMS-based fuel cell may be of a solid oxide type (SOFC), a solid polymer type (SPFC), or a proton exchange membrane type (PEMFC), and each fuel cell basically consists of an anode and a cathode separated by an electrolyte layer. The electrolyte layer can consist of either a solid oxide or solid polymer material, or proton exchange membrane electrolyte materials may be used. Additionally catalyst layers can also separate the electrodes (cathode and anode) from the electrolyte. Gas manifolds are utilized to transport the fuel and oxidant to each cell and provide a path for exhaust gases. The electrical current generated from each cell is drawn away with an interconnect and support structure integrated with the gas manifold. The fuel cells utilize integrated resistive heaters for efficient heating of the materials. By combining MEMS technology with thin-film deposition technology, thin-film fuel cells having microflow channels and full-integrated circuitry can be produced that will lower the operating temperature an will yield an order of magnitude greater power density than the currently known fuel cells.

  6. Molten carbonate fuel cell separator

    DOEpatents

    Nickols, R.C.

    1984-10-17

    In a stacked array of molten carbonate fuel cells, a fuel cell separator is positioned between adjacent fuel cells to provide isolation as well as a conductive path therebetween. The center portion of the fuel cell separator includes a generally rectangular, flat, electrical conductor. Around the periphery of the flat portion of the separator are positioned a plurality of elongated resilient flanges which form a gas-tight seal around the edges of the fuel cell. With one elongated flange resiliently engaging a respective edge of the center portion of the separator, the sealing flanges, which are preferably comprised of a noncorrosive material such as an alloy of yttrium, iron, aluminum or chromium, form a tight-fitting wet seal for confining the corrosive elements of the fuel cell therein. This arrangement permits a good conductive material which may be highly subject to corrosion and dissolution to be used in combination with a corrosion-resistant material in the fuel cell separator of a molten carbonate fuel cell for improved fuel cell conductivity and a gas-tight wet seal.

  7. Molten carbonate fuel cell separator

    DOEpatents

    Nickols, Richard C.

    1986-09-02

    In a stacked array of molten carbonate fuel cells, a fuel cell separator is positioned between adjacent fuel cells to provide isolation as well as a conductive path therebetween. The center portion of the fuel cell separator includes a generally rectangular, flat, electrical conductor. Around the periphery of the flat portion of the separator are positioned a plurality of elongated resilient flanges which form a gas-tight seal around the edges of the fuel cell. With one elongated flange resiliently engaging a respective edge of the center portion of the separator, the sealing flanges, which are preferably comprised of a noncorrosive material such as an alloy of yttrium, iron, aluminum or chromium, form a tight-fitting wet seal for confining the corrosive elements of the fuel cell therein. This arrangement permits a good conductive material which may be highly subject to corrosion and dissolution to be used in combination with a corrosion-resistant material in the fuel cell separator of a molten carbonate fuel cell for improved fuel cell conductivity and a gas-tight wet seal.

  8. Orbiter fuel cell improvement assessment

    NASA Technical Reports Server (NTRS)

    Johnson, R. E.

    1981-01-01

    The history of fuel cells and the theory of fuel cells is given. Expressions for thermodynamic and electrical efficiencies are developed. The voltage losses due to electrode activation, ohmic resistance and ionic diffusion are discussed. Present limitations of the Orbiter Fuel Cell, as well as proposed enhancements, are given. These enhancements are then evaluated and recommendations are given for fuel cell enhancement both for short-range as well as long-range performance improvement. Estimates of reliability and cost savings are given for enhancements where possible.

  9. Orbiter fuel cell improvement assessment

    NASA Technical Reports Server (NTRS)

    Johnson, R. E.

    1981-01-01

    The history of fuel cells and the theory of fuel cells is given. Expressions for thermodynamic and electrical efficiencies are developed. The voltage losses due to electrode activation, ohmic resistance and ionic diffusion are discussed. Present limitations of the Orbiter Fuel Cell, as well as proposed enhancements, are given. These enhancements are then evaluated and recommendations are given for fuel cell enhancement both for short-range as well as long-range performance improvement. Estimates of reliability and cost savings are given for enhancements where possible.

  10. What happens inside a fuel cell? Developing an experimental functional map of fuel cell performance.

    PubMed

    Brett, Daniel J L; Kucernak, Anthony R; Aguiar, Patricia; Atkins, Stephen C; Brandon, Nigel P; Clague, Ralph; Cohen, Lesley F; Hinds, Gareth; Kalyvas, Christos; Offer, Gregory J; Ladewig, Bradley; Maher, Robert; Marquis, Andrew; Shearing, Paul; Vasileiadis, Nikos; Vesovic, Velisa

    2010-09-10

    Fuel cell performance is determined by the complex interplay of mass transport, energy transfer and electrochemical processes. The convolution of these processes leads to spatial heterogeneity in the way that fuel cells perform, particularly due to reactant consumption, water management and the design of fluid-flow plates. It is therefore unlikely that any bulk measurement made on a fuel cell will accurately represent performance at all parts of the cell. The ability to make spatially resolved measurements in a fuel cell provides one of the most useful ways in which to monitor and optimise performance. This Minireview explores a range of in situ techniques being used to study fuel cells and describes the use of novel experimental techniques that the authors have used to develop an 'experimental functional map' of fuel cell performance. These techniques include the mapping of current density, electrochemical impedance, electrolyte conductivity, contact resistance and CO poisoning distribution within working PEFCs, as well as mapping the flow of reactant in gas channels using laser Doppler anemometry (LDA). For the high-temperature solid oxide fuel cell (SOFC), temperature mapping, reference electrode placement and the use of Raman spectroscopy are described along with methods to map the microstructural features of electrodes. The combination of these techniques, applied across a range of fuel cell operating conditions, allows a unique picture of the internal workings of fuel cells to be obtained and have been used to validate both numerical and analytical models.

  11. Fuel cell development for transportation: Catalyst development

    SciTech Connect

    Doddapaneni, N.; Ingersoll, D.

    1996-12-31

    Fuel cells are being considered as alternative power sources for transportation and stationary applications. The degradation of commonly used electrode catalysts (e.g. Pt, Ag, and others) and corrosion of carbon substrates are making commercialization of fuel cells incorporating present day technologies economically problematic. Furthermore, due to the instability of the Pt catalyst, the performance of fuel cells declines on long-term operation. When methanol is used as the fuel, a voltage drop, as well as significant thermal management problems can be encountered, the later being due to chemical oxidation of methanol at the platinized carbon at the cathode. Though extensive work was conducted on platinized electrodes for both the oxidation and reduction reactions, due to the problems mentioned above, fuel cells have not been fully developed for widespread commercial use. Several investigators have previously evaluated metal macrocyclic complexes as alternative catalysts to Pt and Pt/Ru in fuel cells. Unfortunately, though they have demonstrated catalytic activity, these materials were found to be unstable on long term use in the fuel cell environment. In order to improve the long-term stability of metal macrocyclic complexes, we have chemically bonded these complexes to the carbon substrate, thereby enhancing their catalytic activity as well as their chemical stability in the fuel cell environment. We have designed, synthesized, and evaluated these catalysts for O{sub 2} reduction, H{sub 2} oxidation, and direct methanol oxidation in Proton Exchange Membrane (PEM) and aqueous carbonate fuel cells. These catalysts exhibited good catalytic activity and long-term stability. In this paper we confine our discussion to the initial performance results of some of these catalysts in H{sub 2}/O{sub 2} PEM fuel cells, including their long-term performance characteristics as well as CO poisoning effects on these catalysts.

  12. Low Cost Reversible fuel cell systems

    SciTech Connect

    Technology Management Inc.

    2003-12-30

    This final report summarizes a 3-phase program performed from March 2000 through September 2003 with a particular focus on Phase III. The overall program studied TMI's reversible solid oxide stack, system concepts, and potential applications. The TMI reversible (fuel cell-electrolyzer) system employs a stack of high temperature solid-oxide electrochemical cells to produce either electricity (from a fuel and air or oxygen) or hydrogen (from water and supplied electricity). An atmospheric pressure fuel cell system operates on natural gas (or other carbon-containing fuel) and air. A high-pressure reversible electrolyzer system is used to make high-pressure hydrogen and oxygen from water and when desired, operates in reverse to generate electricity from these gases.

  13. Static regenerative fuel cell system for use in space

    NASA Technical Reports Server (NTRS)

    Levy, Alexander H. (Inventor); VanDine, Leslie L. (Inventor); Trocciola, John C. (Inventor)

    1989-01-01

    The cell stack can be operated as a fuel cell stack or as an electrolysis cell stack. The stack consists of a series of alternate fuel cell subassemblies with intervening electrolysis cell subassemblies, and interspersed cooling plates. The water produced and consumed in the two modes of operation migrates between adjacent cell subassemblies. The component plates are annular with a central hydrogen plenum and integral internal oxygen manifolds. No fluid pumps are needed to operate the stack in either mode.

  14. 1986 fuel cell seminar: Program and abstracts

    SciTech Connect

    1986-10-01

    Ninety nine brief papers are arranged under the following session headings: gas industry's 40 kw program, solid oxide fuel cell technology, phosphoric acid fuel cell technology, molten carbonate fuel cell technology, phosphoric acid fuel cell systems, power plants technology, fuel cell power plant designs, unconventional fuels, fuel cell application and economic assessments, and plans for commerical development. The papers are processed separately for the data base. (DLC)

  15. Fuel Cell Powered Lift Truck

    SciTech Connect

    Moulden, Steve

    2015-08-20

    This project, entitled “Recovery Act: Fuel Cell-Powered Lift Truck Sysco (Houston) Fleet Deployment”, was in response to DOE funding opportunity announcement DE-PS36-08GO98009, Topic 7B, which promotes the deployment of fuel cell powered material handling equipment in large, multi-shift distribution centers. This project promoted large-volume commercialdeployments and helped to create a market pull for material handling equipment (MHE) powered fuel cell systems. Specific outcomes and benefits involved the proliferation of fuel cell systems in 5-to 20-kW lift trucks at a high-profile, real-world site that demonstrated the benefits of fuel cell technology and served as a focal point for other nascent customers. The project allowed for the creation of expertise in providing service and support for MHE fuel cell powered systems, growth of existing product manufacturing expertise, and promoted existing fuel cell system and component companies. The project also stimulated other MHE fleet conversions helping to speed the adoption of fuel cell systems and hydrogen fueling technology. This document also contains the lessons learned during the project in order to communicate the successes and difficulties experienced, which could potentially assist others planning similar projects.

  16. In situ PEM fuel cell water measurements

    SciTech Connect

    Borup, Rodney L; Mukundan, Rangachary; Davey, John R; Spendelow, Jacob S; Hussey, Daniel S; Jacobson, David L; Arif, Muhammad

    2009-01-01

    Efficient PEM (Polymer Electrolyte Membrane) fuel cell performance requires effective water management. To achieve a deeper understanding of water transport and performance issues associated with water management, we have conducted in situ water examinations to help understand the effects of components and operations. High Frequency Resistance (HFR), AC Impedance and Neutron imaging were used to measure water content in operating fuel cells, with various conditions, including current density, relative humidity, inlet flows, flow orientation and variable Gas Diffusion Layer (GDL) properties. High resolution neutron radiography was used to image fuel cells during a variety of conditions. The effect of specific operating conditions, including flow direction (co-flow or counter-flow) was examined. Counter-flow operation was found to result in higher water content than co-flow operation, which correlates to lower membrane resistivity. A variety of cells were used to quantify the membrane water in situ during exposure to saturated gases, during fuel cell operation, and during hydrogen pump operation. The quantitative results show lower membrane water content than previous results suggested.

  17. Fuel processing requirements and techniques for fuel cell propulsion power

    SciTech Connect

    Kumar, R.; Ahmed, S.; Yu, M.

    1993-08-01

    Fuels for fuel cells in transportation systems are likely to be methanol, natural gas, hydrogen, propane, or ethanol. Fuels other than hydrogen wig need to be reformed to hydrogen on-board the vehicle. The fuel reformer must meet stringent requirements for weight and volume, product quality, and transient operation. It must be compact and lightweight, must produce low levels of CO and other byproducts, and must have rapid start-up and good dynamic response. Catalytic steam reforming, catalytic or noncatalytic partial oxidation reforming, or some combination of these processes may be used. This paper discusses salient features of the different kinds of reformers and describes the catalysts and processes being examined for the oxidation reforming of methanol and the steam reforming of ethanol. Effective catalysts and reaction conditions for the former have been identified; promising catalysts and reaction conditions for the latter are being investigated.

  18. Carbon tolerance, electrochemical performance and stability of solid oxide fuel cells with Ni/yttria stabilized zirconia anodes impregnated with Sn and operated with methane

    NASA Astrophysics Data System (ADS)

    Singh, Anand; Hill, Josephine M.

    2012-09-01

    Carbon formation on conventional Ni/YSZ anodes is a major problem when solid oxide fuel cells (SOFC) are operated with hydrocarbons. Carbon formation reduces the operational stability and lifetime of SOFC. In this paper, the influence of the addition of Sn to Ni/YSZ anodes (100 micron) on the carbon tolerance, electrochemical performance and stability of the anodes when operated with CH4 is studied. Sn is incorporated into the Ni/YSZ anodes of electrolyte-supported SOFC by impregnation (1 and 5 wt% Sn with respect to Ni). Addition of Sn to Ni/YSZ anodes does not reduce the carbon formation when SOFC are operated with CH4 at low steam to carbon ratios (<0.03) and high temperatures (1013 and 1073 K). Severe coking and metal dusting occurs on Sn-impregnated Ni/YSZ anodes when operated at OCV and 1073 K with dry CH4. Addition of higher amounts of Sn (5%) reduces electrochemical performance of Ni/YSZ anodes in H2 and also reduces the carbon gasification rates, leading to higher carbon accumulation. The Sn content in the anode decreases after operation at 1073 K for 30 h. Hence retaining Sn in the anode might be difficult in actual stack operations at high temperatures (1073 K) and long durations (>40,000 h).

  19. Tubular solid oxide fuel cell current collector

    DOEpatents

    Bischoff, Brian L.; Sutton, Theodore G.; Armstrong, Timothy R.

    2010-07-20

    An internal current collector for use inside a tubular solid oxide fuel cell (TSOFC) electrode comprises a tubular coil spring disposed concentrically within a TSOFC electrode and in firm uniform tangential electrical contact with the electrode inner surface. The current collector maximizes the contact area between the current collector and the electrode. The current collector is made of a metal that is electrically conductive and able to survive under the operational conditions of the fuel cell, i.e., the cathode in air, and the anode in fuel such as hydrogen, CO, CO.sub.2, H.sub.2O or H.sub.2S.

  20. Effect of fed-batch vs. continuous mode of operation on microbial fuel cell performance treating biorefinery wastewater

    DOE PAGES

    Pannell, Tyler C.; Goud, R. Kannaiah; Schell, Daniel J.; ...

    2016-05-01

    Bioelectrochemical systems have been shown to treat low-value biorefinery streams while recovering energy, however, low current densities and anode conversion efficiencies (ACE) limit their application. A bioanode was developed via enrichment of electroactive biofilm under fed-batch and continuous feeding conditions using corn stover-derived waste stream. The continuously-fed MFC exhibited a current density of 5.8±0.06 A/m2 and an ACE of 39%±4. The fed-batch MFC achieved a similar current density and an ACE of 19.2%, however, its performance dropped after 36 days of operation to 1.1 A/m2 and 0.5%, respectively. In comparison, the ACE of the continuously-fed MFC remained stable achieving anmore » ACE of 30% ± 3 after 48 days of operation. An MFC treating a biorefinery stream post fuel separation achieved a current density of 10.7±0.1 A/m2 and an ACE of 57% ± 9 at an organic loading of 12.5 g COD/L-day. Characterization of the microbial communities indicate higher abundance of Firmicutes and Proteobacteria and lower abundance of Bacteriodetes and a higher level of Geobacter spp. (1.4% vs. 0.2%) in continuously-fed MFC vs. fed-batch MFC. Finally, the results demonstrate that limiting substrate to the equivalent maximum current that the anode can generate, maintains MFC performance over a long term for high strength wastewaters, such as those generated in the biorefinery.« less