Grantee Research Project Results
2001 Progress Report: Stationary Power Generation Via Solid Oxide Fuel Cells: A Response to Pollution and Global Warming
EPA Grant Number: R828598C778Subproject: this is subproject number 778 , established and managed by the Center Director under grant R828598
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: EAGLES - Consortium for Estuarine Ecoindicator Research for the Gulf of Mexico
Center Director: Brouwer, Marius
Title: Stationary Power Generation Via Solid Oxide Fuel Cells: A Response to Pollution and Global Warming
Investigators: Thrasher, Joseph , Street, Shane C. , Wiest, John M. , Zangari, Giovanni , Reddy, Ramana
Institution: The University of Alabama
EPA Project Officer: Aja, Hayley
Project Period: September 1, 2000 through August 31, 2004
Project Period Covered by this Report: September 1, 2000 through August 31, 2001
RFA: Gulf Coast Hazardous Substance Research Center (Lamar University) (1996) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , Targeted Research
Objective:
The project consists of the following objectives: (1) develop high-performance electrodes that are compatible with the electrolyte material and exhibit low polarization during service, (2) greatly lower the total resistance of the solid-oxide electrolyte at lower temperatures without reducing its thickness below about 5 microns by using a nanoparticle approach, (3) successfully model the transport of oxide through the solid-oxide electrolyte in conjunction with the synthetic approach, (4) develop new materials, design and fabrication methods for bipolar plates with high conductivity and high corrosion resistance, including lightweight alloys and composite materials with surface coatings, and (5) integrate the selected components developed from the preceding tasks into sub-assemblies and later into an entire fuel cell of high performance and low cost.
Progress Summary:
The most common anode materials in current SOFC applications are Ni/YSZ (nickel/yttria-stabilized zirconia) cermets, made by reducing NiO/YSZ in-situ under fuel exposure in the SOFC cell. The nickel is dispersed in the YSZ as a solid solution and acts as a catalyst for the oxidation reaction of the fuel at the three-phase boundary where the electrolyte, anode and fuel gas meet. Good cell performance requires that the nickel and the YSZ form continuous electronic and ionic pathways, respectively. Thus, the microstructure of the Ni/YSZ anode is an important parameter, and it is dependent on the preparation technique. Typically, the NiO/YSZ precursor material is made by mechanical mixing of NiO and YSZ powders. This method does not usually yield highly uniform Ni dispersion in the cermet, limiting SOFC performance. Preparation of YSZ by the sol-gel method has been widely reported. We have extended this method to the preparation of ultrafine NiO/YSZ for the first time (manuscript in preparation). A 50 wt.% Ni in 8%YSZ solid solution was prepared by two sol-gel routes that differed in the order of addition of the Ni source solution to the hydrolysis mixture. The resulting powders, dried, calcined and sintered have been examined by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray fluorescence. Their surface areas were determined using BET isotherms. The powders were also studied using thermal gravimetric analysis and differential scanning calorimetry. We find that well-dispersed Ni/YSZ is formed following crystallization of the YSZ above 700 °C, and reduction under hydrogen. Typical Ni crystallite size is about 20 nm, with zirconia crystallite size below 10 nm. Pore formation is apparent following reduction of NiO, without apparent macroscopic volume change in the pressed pellets. The materials will be further characterized for their electrochemical transport and catalytic properties. We anticipate that further control of the crystallite sizes may be gained by varying the temperature and/or pH of the sol-gel reaction mixture. A high-temperature electrochemical cell for testing the aforementioned micro- and nanostructured materials is being constructed. The cell consists essentially of a temperature-controlled chamber, wherein the various components (electrolyte, anode and cathode) can be easily substituted. A reference cell, consisting of standard commercial components, will be used to determine a benchmark performance to be used later in the assessment of the single components. The cell is designed to enable a series of electrochemical measurements on various experimental cell components - thus evaluating their performance - and to work in a SOFC mode. The latter will allow measurements of activity and selectivity of the materials of choice, using various inlet gases and analyzing the composition of the outlet gases. The high operating temperature of the current generation SOFCs (950-1000 °C) puts severe constraints on selection of materials that can be used over the lifetime of the cell. A constant desire exists to reduce the operating temperature in order to widen the choice of materials for the metallic or ceramic interconnects, increase the life time of cells and stacks, and decrease material and fabrication costs. It is envisioned that the cost of the interconnect material and its fabrication can be drastically reduced by using metallic interconnects from stainless steels. We are also examining the use of plasma spraying for interconnect deposition instead of electrochemical vapor deposition (EVD). Until now, metals or electrically conducting ceramics have been used for interconnect structures in SOFCs. However, when metallic interconnect structures are used at temperatures of 600 °C or higher, oxides are formed on their surfaces giving rise to considerably increased contact resistance and thus increased power losses due to resistance. The requirements for an interconnect material include low thermal expansion, high thermal conductivity, high electronic conductivity, chemical stability in both oxidizing and reducing environments. Metals that satisfy these criteria are superalloys, that is, metal alloys typically comprising iron, nickel, chromium, and manganese. Such superalloys include Austenitic stainless steels, Inconel, and Haynes alloys. Oxidation of the interconnect structure can be minimized by applying a layer of a metal, such as manganese, to the side of the superalloy interconnect structure facing the anode of the fuel cell. An oxide phase, such as manganese chromite, is formed on the alloy surface. The electrical resistivity of manganese chromite thus formed is lower than that of chromate. The metal layer should be sufficiently thick so as to prevent metallic interdiffusion under fuel cell operating conditions and preferably has a thickness in a range about 0.01-5 Å. The metal layer can be deposited on to the interconnect by any of the following ways: electroplating, electroless plating, or sputtering. The proposed interconnect materials are being subjected to oxidation and conductivity studies prior to their integration into the fuel cell stack and subsequent under fuel cell operating conditions. System integration software currently being developed for PEM fuel cells is being extended to our SOFC fuel cell stack.
Future Activities:
We will continue our focus on the synthesis and characterization - conductivity, catalytic activity, and permeability - of nanostructured electrolytes and electrode materials with high conductivity at low temperatures. No reports on the performance of a SOFC based on nanostructured materials have appeared yet due to the difficulties encountered during compaction and calcination, which generally lead to extensive grain growth. We propose to attempt synthesis of the materials in nanocrystalline powder form using colloidal and/or reverse emulsion techniques. The particles will be prepared with or without a protective coating, and compaction and sintering conditions will be optimized in order to avoid to the maximum possible extent grain growth, and to consequently maintain the unconventional properties expected from nanocrystalline materials. According to the latest findings, lanthanum gallate and ceria-based oxides will be mainly considered as electrolytes. Reference materials will be initially synthesized by compaction and sintering of commercial powders, in order to reproduce results available in the literature. Successively, the same materials will be synthesized in our labs, and efforts will be made to minimize the grain size of these materials upon compaction and sintering by employing techniques such as simultaneous heating and compaction, or rapid thermally annealing, well known and applied in the production of nanostructured permanent magnets. Previously, in order to achieve high enough power densities, SOFC had to be run at temperatures in excess of 800 °C where deposition of carbon can take place, thereby fouling the electrode. To avoid carbon deposition in the cell, either lower temperatures of operation with ceria-based anodes or anodes containing copper instead of nickel have been used. The latter of these studies makes use of a metal that is know to catalyze C-H bond activation but not C-C bond activation. Herein, we propose to study additional metals such as silver, possibly even gold or zinc, and mixture thereof (with and without copper) in an effort to prepare other anodes that will facilitate direct oxidation without carbon generation. Ni-doped ceria and Sm-Sr-cobaltates electrodes will also be prepared and studied, as they have been shown to exhibit very good performance in microcrystalline form between 600-800 °C. We will also investigate YSZ modified by a low weight percent of vanadia (V2O5). Vanadia has outstanding oxygen transport properties, which we believe may improve the oxygen ion conduction in the electrolyte by providing labile oxygen vacancies in the matrix. Electrolytes and electrode samples will be compacted and sintered in a cylindrical shape. Ionic and electronic conductivity will be determined as function of temperature by use of four point probes and a high-temperature electrochemical cell. The latter is being assembled using various components purchased with GCHSRC/UA funds. The same cell will be used to perform electrochemical measurements on various experimental cell components and thus evaluate their performance. Further measurements of activity and selectivity of the materials of choice will be performed by using the electrochemical cell in a SOFC mode, with inlet and outlet gases and chemical analysis of the latter. A detailed analysis of the dependence of functional properties and performance on the average grain size of the compacted samples will be performed by extensive microscopy of the compacted samples. We anticipate this work to result in the selection of optimum materials and best processing conditions for the production of electrolytes and electrodes with good performance at temperature down to 500 °C.
Journal Articles:
No journal articles submitted with this report: View all 2 publications for this subprojectSupplemental Keywords:
RFA, Scientific Discipline, Air, TREATMENT/CONTROL, Sustainable Industry/Business, Sustainable Environment, Environmental Chemistry, Physics, climate change, Chemistry, Technology, Air Pollution Effects, Technology for Sustainable Environment, Environmental Monitoring, New/Innovative technologies, Chemistry and Materials Science, Ecological Risk Assessment, Engineering, Environmental Engineering, Atmosphere, Engineering, Chemistry, & Physics, atmospheric carbon dioxide, molecular dynamics, green engineering, nanotechnology, environmental sustainability, energy generation, global change, nanocrystalline electrodes, environmentally applicable nanoparticles, greenhouse gases, stationary power generation, carbon dioxide, sustainability, innovative technology, innovative technologies, global warming, Global Climate ChangeProgress and Final Reports:
Original AbstractMain Center Abstract and Reports:
R828598 EAGLES - Consortium for Estuarine Ecoindicator Research for the Gulf of Mexico Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R822721C529 Environmentally Acceptable Endpoints: Risk Based Remediation Using Bioremediation
R822721C552 Degradative Solidification/Stabilization Technology for Chlorinated Hydrocarbons
R822721C569 Treatment and Product Recovery: Supercritical Water Oxidation of Nylon Monomer Manufacturing Waste
R822721C620 Colloidal Fouling of Membranes: Implications in the Treatment of Textile Dye Wastes and Water Reuse
R822721C626 Catalytic Hydroprocessing of Chlorinated Organics
R822721C627 The Interaction of Microbial Activity and Zero Valent Iron Permeable Barrier Technology
R822721C630 Microbial Cometabolism of Recalcitrant Chemicals in Contaminated Air Streams
R822721C633 Catalyst Lifetime Studies for Chlorocarbon Steam Reforming
R822721C635 Electrokinetic/Surfactant-Enhanced Remediation of Hydrophobic Pollutants in Low Permeability Subsurface Environments
R822721C636 Transformation Reactions of Nitroaromatic and Nitrogen Heterocyclic Compounds on Granular Activated Carbon (GAC) Surfaces: Enhancement of GAC Adsorption in Natural and Engineered Environmental Systems
R822721C640 Environmentally Friendly Organic Synthesis in Supercritical Fluids
R822721C645 Development and Evaluation of an Integrated Model to Facilitate Risk-Based Corrective Action at Superfund Sites
R822721C651 Adjustable Biopolymer Chelators for Cadmium, Lead and Mercury
R822721C653 New Electrochemically Smart Catalysts for Hazardous Waste Management and Development of Capillary Electrophoresis for Analysis of their Products
R822721C655 Soil Sampling in South Alabama Oil Fields
R822721C659 Subsurface Contamination Site Characterization via a Computer-Aided Visual Tool
R822721C661 New Insoluble supports for Protein Immobilization for Use in Metalloprotein Affinity Metal Chromatography
R822721C663 Soil Remediation with Ultra-High-Efficiency Hydrocyclones
R822721C669 Solid Acid Catalyzed Alkylation in Supercritical Fluids
R822721C679 Regeneration/Reactivation of Carbon Adsorbents by Radio Frequency (RF) Induction Heating
R822721C687 Improved Halogen Resistance of Catalytic Oxidation
R822721C696 Phytoremediation and Bioremediation of Land Contaminated By PAHs, PCBs, and TNT
R822721C697 Fundamental and Kinetic Investigation of Sorbent Technology for Optimum Mercury Emission Control
R822721C700 Effects of Natural and Cyclic Variations on Contaminant Fate and Transport
R822721C703 Enhancement of DNAPL Dissolution Rates by Dechlorinating Anaerobes
R826694C620 Colloidal Fouling of Membranes: Implications in the Treatment of Textile Dye Wastes and Water Reuse
R826694C625 Enhanced Treatment of DNAPLs Contaminated Soils and Groundwater Using Biosurfactants: In-Situ Bioremediation
R826694C626 Catalytic Hydroprocessing of Chlorinated Wastes
R826694C627 The Interaction of Microbial Activity and Zero Valent Iron Permeable Barrier Technology
R826694C629 Biofiltration of BTEX in Petroleum-Contaminated Soil Remediation Off-Gas
R826694C630 Microbial Cometabolism of Recalcitrant Chemicals in Contaminated Air Streams
R826694C633 Catalyst Lifetime Studies for Chlorocarbon Steam Reforming
R826694C635 Electrokinetic/Surfactant-Enhanced Remediation of Hydrophobic Pollutants in Low Permeability Subsurface Environments
R826694C636 Transformation Reactions of Nitroaromatic and Nitrogen Heterocyclic Compounds on Granular Activated Carbon (GAC) Surfaces: Enhancement of GAC Adsorption in Natural and Engineered Environmental Systems
R826694C640 Environmentally Friendly Organic Synthesis in Supercritical Fluids
R826694C645 Development and Evaluation of an Integrated Model to Facilitate Risk-Based Corrective Action at Superfund Sites
R826694C651 Adjustable Biopolymer Chelators for Cadmium, Lead, and Mercury Remeidation
R826694C659 Subsurface Contamination Site characterization Via a Computer-Aided Visual Tool
R826694C661 New Insoluble supports for Protein Immobilization for Use in Metalloprotein Affinity Metal Chromatography
R826694C669 Solid Acid Catalyzed Alkylation in Supercritical Reaction Media
R826694C679 Regeneration and Reactivation of Carbon Adsorbents by Radio Frequency Induction Heating
R826694C696 Phytoremediation and Bioremediation of Land Contaminated By PAHs, PCBs, and TNT
R826694C697 Fundamental and Kinetic Investigation of Sorbent Technology for Optimum Mercury Emission Control
R826694C700 Effects of Natural Cyclic Variations on Contaminated Fate and Transport
R826694C703 Enhancement of DNAPL Dissolution Rates by Dechlorinating Anaerobes
R826694C705 A Pilot Plant for Producing Mixed Ketones from Waste Biomass
R826694C722 The Effects of an Oily-Phase on VOC Emissions from Industrial Wastewater
R826694C724 Mercury Removal from Stack Gas by Aqueous Scrubbing
R826694C725 Transport, Fate and Risk Implications of Environmentally Acceptable Endpoint Decisions
R826694C731 Development and Application of a Real-Time Optical Sensor for Atmospheric Formaldehyde
R826694C734 An Advanced System for Pollution Prevention in Chemical Complexes
R828598C001 Field Study Abstract: A Model of Ambient Air Pollution in Southeast Texas Using Artificial Neural Network Technology
R828598C002 Hollow Fiber Membrane Bioreactors for Treating Water and Air Streams Contaminated with Chlorinated Solvents
R828598C003 Fugitive Emissions of Hazardous Air Pollutants from On-Site Industrial Sewers
R828598C004 Biofiltration Technology Development
R828598C005 A Risk-Based Decision Analysis Approach for Aquifers Contaminated with DNAPLs
R828598C006 In-Situ Remediation for Contaminated Soils Using Prefabricated Vertical Drains
R828598C007 Membrane Technology Selection System for the Metal Finishing Industry
R828598C008 Sequential Environments for Enhanced Bioremediation of Chlorinated Aliphatic Hydrocarbons
R828598C009 Waste Minimization in the Magnetic Tape Industry: Waterborne Coating Formulations for Magnetic Tape Manufacture
R828598C010 Soil Remediation by Agglomeration with Petroleum Coke
R828598C011 Recovery of Dilute Phosphoric Acid in Waste Streams Using Waste Gas Ammonia: The Regenerative MAP/DAP Process
R828598C012 Stochastic Risk Assessment for Bioremediation
R828598C013 Selective Removal of Heavy Metals from Wastewater by Chelation in Supercritical Fluids
R828598C014 Optimization of Treatment Technologies for Detoxification of PCB Contaminated Soils
R828598C015 Wastewater Remediation by Catalytic Wet Oxidation
R828598C016 Permanence of Metals Containment in Solidified and Stabilized Wastes
R828598C017 Combustion Enhancement by Radial Jet Reattachment - Low Generation of Hazardous Gases and High Thermal Efficiency
R828598C018 A Process To Convert Industrial Biosludge and Paper Fines to Mixed Alcohol Fuels
R828598C019 Homogeneous Catalysis in Supercritical Carbon Dioxide
R828598C020 Ultrasonic Enhancement of the Removal of Heavy Metals
R828598C021 The Binding Chemistry and Leaching Mechanisms of Advanced Solidification/Stabilization Systems for Hazardous Waste Management
R828598C022 Development of an Air-Stripping and UV/H2O2 Oxidation Integrated Process To Treat a Chloro-Hydrocarbon-Contaminated Ground Water
R828598C023 A Comparative Study of Siting Opposition in Two Counties
R828598C024 Sonochemical Treatment of Hazardous Organic Compounds II: Process Optimization and Pathway Studies
R828598C025 Laser Diagnostics of the Combustion Process within a Rotary Kiln Incinerator
R828598C026 Use of Inorganic Ion Exchangers for Hazardous Waste Remediation
R828598C027 Kaolinite Sorbent for the Removal of Heavy Metals from Incinerated Lubricating Oils
R828598C028 Destruction of Chlorinated Hydrocarbons in Process Streams Using Catalytic Steam Reforming
R828598C029 Integrated Process Treatment Train (Bioremediation {Aerobic/Anaerobic} and Immobilization) for Texas Soils Contaminated with Combined Hazardous Wastes
R828598C030 Photo-Oxidation by H2O2/VisUV of Off-Gas Atmospheric Emissions from Industrial and Environmental Remediation Sources
R828598C031 Concentrated Halide Extraction and Recovery of Lead from Soil
R828598C032 Biodegradable Surfactant for Underground Chlorinated Solvent Remediation
R828598C033 A Software Guidance System for Choosing Analytical Subsurface Fate and Transport Models Including a Library of Computer Solutions for the Analytical Models
R828598C034 Hydrodynamic Modeling of Leachate Recirculating Landfill
R828598C035 Measurement of Oxygen Transfer Rate in Soil Matrices
R828598C036 Sorbent Technology for Multipollutant Control During Fluidized Bed Incineration
R828598C037 Pollution Prevention by Process Modification Using On-Line Optimization
R828598C038 Pollution Prevention by Process Modification
R828598C039 Water Solubility and Henry's Law Constant
R828598C040 Transferring Technical Information on Hazardous Substance Research by Publishing on the World Wide Web
R828598C041 Stress Protein Responses to Multiple Metal Exposure in Grass Shrimp
R828598C042 Life-Cycle Environmental Costing for Managing Pollution Prevention in the Chemical and Petroleum Refining Industries: A Cross-Border Approach
R828598C687 Improved Halogen Resistance of Catalytic Oxidation Through Efficient Catalyst Testing
R828598C696 Phytoremediation and Bioremediation of Land Contaminated By PAHs, PCBs, and TNT
R828598C697 Fundamental and Kinetic Investigation of Sorbent Technology for Optimum Mercury Emission Control
R828598C700 Effects of Natural Cyclic Variations on Contaminated Fate and Transport
R828598C703 Enhancement of DNAPL Dissolution Rates by Dechlorinating Anaerobes
R828598C705 A Pilot Plant for Producing Mixed Ketones from Waste Biomass
R828598C722 The Effects of an Oily-Phase on VOC Emissions from Industrial Wastewater
R828598C724 Mercury Removal from Stack Gas by Aqueous Scrubbing
R828598C725 Transport, Fate and Risk Implications of Environmentally Acceptable Endpoint Decisions
R828598C731 Development and Application of a Real Time Optical Sensor for Atmospheric Formaldehyde
R828598C734 An Advanced System for Pollution Prevention in Chemical Complexes
R828598C743 Field Demonstration of Ultrasound Enhancement of Permeable Treatment Walls
R828598C744 Optical Fibers Coated With Titania Membrane/UV-Generating Crystal in a Distributed-Light Photoreactor for VOC Oxidation
R828598C749 Characterization and Modeling of Indoor Particulate Contaminants In a Heavily Industrialized Community
R828598C753 Adsolubilization and Photocatalysis in a Semiconducting Monolithic Reactor for Wastewater Treatment
R828598C754 Remote Detection of Gas Emissions in Industrial Processes
R828598C759 Searching for Optimum Composition of Phosphogypsum: Fly ash: Cement Composites for Oyster Culch Materials
R828598C761 Development of a Phytologically-Based Biosorptive Water Treatment Process
R828598C766 Chlorinated Solvent Impact and Remediation Strategies for the Dry Cleaning Industry
R828598C769 Soil/Sediment Remediation by Hot Water Extraction Combined with In-Situ Wet Oxidation
R828598C771 Fluoracrylate Polymer Supported Ligands as Catalysts for Environmentally Benign Synthesis in Supercritical Fluids
R828598C774 The Feasibility of Electrophoretic Repair of Impoundment Leaks
R828598C777 Surfactant Enhanced Photo-oxidation of Wastewaters
R828598C778 Stationary Power Generation Via Solid Oxide Fuel Cells: A Response to Pollution and Global Warming
R828598C786 Photocatalytic Recovery of Sulfur and Hydrogen From Hydrogen Sulfide
R828598C787 Biosurfactant Produced from Used Vegetable Oil for removal of Metals From Wastewaters and Soils
R828598C789 Genetic Engineering of Enzymatic Cyanide Clearance
R828598C791 Characterizing the Intrinsic Remediation of MTBE at Field Sites
R828598C799 Simultaneous Water Conservation/Recycling/Reuse and Waste Reduction in Semiconductor Manufacturing
R828598C801 Building Defined Mixed Cultures To Biodegrade Diverse Mixtures Of Chlorinated Solvents
R828598C802 Engineering of Nanocrystal Based Catalytic Materials for Hydroprocessing of Halogenated Organics
R828598C807 Commercial Demonstration of Hydrogen Peroxide Injection to Control NOx Emissions from Combustion Sources
R828598C809 Evaluating Source Grouting and ORC for Remediating MTBE Sites
R828598C810 Application of Total Cost Assessment To Process Design In the Chemical Industry
R828598C846 Quantitative Demonstration of Source-Zone Bioremediation in A Field-Scale Experimental Controlled Release System
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.
Project Research Results
Main Center: R828598
359 publications for this center
90 journal articles for this center