US20100028732A1 - Method an apparatus for operating a solid-oxide fuel cell stack with a mixed ionic/electronic conducting electrolyte - Google Patents

Method an apparatus for operating a solid-oxide fuel cell stack with a mixed ionic/electronic conducting electrolyte Download PDF

Info

Publication number
US20100028732A1
US20100028732A1 US10/588,897 US58889705A US2010028732A1 US 20100028732 A1 US20100028732 A1 US 20100028732A1 US 58889705 A US58889705 A US 58889705A US 2010028732 A1 US2010028732 A1 US 2010028732A1
Authority
US
United States
Prior art keywords
fuel cell
solid oxide
cell stack
oxide fuel
stack
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US10/588,897
Other languages
English (en)
Inventor
Robert Leah
Nigel Peter Brandon
Athol Duckett
Karim El Koury
Martin Schmidt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ceres Power Ltd
Original Assignee
Ceres Power Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ceres Power Ltd filed Critical Ceres Power Ltd
Assigned to CERES POWER LIMITED reassignment CERES POWER LIMITED ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BRANDON, NIGEL PETER, EL KOURY, KARIM, LEAH, ROBERT, SCHMIDT, MARTIN, DUCKETT, ATHOL
Publication of US20100028732A1 publication Critical patent/US20100028732A1/en
Priority to US13/898,417 priority Critical patent/US20130260269A1/en
Priority to US15/640,333 priority patent/US10283792B2/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04694—Processes for controlling fuel cells or fuel cell systems characterised by variables to be controlled
    • H01M8/04858—Electric variables
    • H01M8/04925—Power, energy, capacity or load
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04007—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids related to heat exchange
    • H01M8/04014—Heat exchange using gaseous fluids; Heat exchange by combustion of reactants
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
    • H01M8/04097—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with recycling of the reactants
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/0432—Temperature; Ambient temperature
    • H01M8/04365—Temperature; Ambient temperature of other components of a fuel cell or fuel cell stacks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/0438—Pressure; Ambient pressure; Flow
    • H01M8/04395—Pressure; Ambient pressure; Flow of cathode reactants at the inlet or inside the fuel cell
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/0438—Pressure; Ambient pressure; Flow
    • H01M8/04417—Pressure; Ambient pressure; Flow of the coolant
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/04537—Electric variables
    • H01M8/04544—Voltage
    • H01M8/04559—Voltage of fuel cell stacks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/04537—Electric variables
    • H01M8/04604—Power, energy, capacity or load
    • H01M8/04619—Power, energy, capacity or load of fuel cell stacks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04694—Processes for controlling fuel cells or fuel cell systems characterised by variables to be controlled
    • H01M8/04701—Temperature
    • H01M8/04731—Temperature of other components of a fuel cell or fuel cell stacks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
    • H01M8/124—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte
    • H01M8/1246—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte the electrolyte consisting of oxides
    • H01M8/126—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte the electrolyte consisting of oxides the electrolyte containing cerium oxide
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
    • H01M2008/1293—Fuel cells with solid oxide electrolytes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a method and apparatus for operating a solid oxide fuel cell stack in order to increase its efficiency, in particular by varying one or more operating conditions of the fuel cell.
  • Solid oxide fuel cells are a promising means of generating electricity from either hydrogen or fossil fuels in a more efficient and environmentally acceptable manner than more traditional generating technologies.
  • traditional SOFCs operate at very high temperatures (greater than 900° C.), and even more recent innovations have only been able to reduce his temperature to 700-800° C.
  • This high temperature of operation leads to significant problems with the materials used in the construction of such fuel cell stacks and the related system components. Materials which can withstand prolonged operation at these temperatures tend to either be expensive, fragile or both. Attempting to use lower cost materials, such as ferritic stainless steels, at high operating temperatures causes problems with stack performance degradation due to oxidation of the metal and migration of volatile chromium species over prolonged periods at these high operating temperatures.
  • YSZ yttrium-doped zirconium oxide
  • mixed ionic/electronic conducting ceramic electrolyte materials which have a high ionic conductivity below 650° C.
  • the most promising and widely used of these low-temperature mixed ionic/electronic conducting electrolyte materials is gadolinium-doped cerium oxide (COO), although there are other materials such as other doped ceria oxides.
  • CGO exhibits good ionic conductivity down to below 500° C.
  • CGO is not as stable as YSZ, and in a reducing atmosphere at temperature (such as that normally found on the anode side of the fuel cell), Ce 4+ ions can be reduced to Ce 3+ . This results in the electrolyte developing some electronic conductivity, resulting in a short-circuit current flowing within the fuel cell. This short-circuit is observed externally as a drop in the cell terminal voltage at open-circuit, and results in a loss of efficiency in converting the energy in the fuel to electricity.
  • a method of operating a solid oxide fuel cell stack with a mixed ionic/electronic conducting electrolyte comprising
  • the operating conditions of the solid oxide fuel cell stack that are varied are preferably at least one of the temperature of the fuel cell stack and the dilution of fuel delivered to the fuel cell stack.
  • CGO is a suitable electrolyte material when the fuel cell operating temperature is below a temperature of 650° C. or more preferably 600° C. This is particularly the case under a high external load, where the flux of oxide ions through the electrolyte tends to reoxidise the Ce 3+ ions to Ce 4+ , thus eliminating the electronic conductivity.
  • the efficiency of a fuel cell stack with an electrolyte including cerium rises rapidly at above about 50% of its rated power, as the short-circuit current becomes small relative to the external circuit current.
  • control system for a solid-oxide fuel cell stack with a mixed ionic/electronic conducting electrolyte, the control system comprising
  • a controller for controlling one or more operating conditions of the stack dependent upon the required power output.
  • the controller may be arranged to control at least one of the temperature of the stack and the dilution of fuel delivered to the stack.
  • a fuel cell stack with a mixed ionic/electronic conducting electrolyte may be provided with a control system according to the second aspect of the present invention.
  • FIG. 1 shows the energy conversion efficiency of a fuel cell with a CGO-based electrolyte plotted against electrical power density at a range of temperatures from 500° C. to 600° C.;
  • FIG. 2 shows the energy conversion efficiency of a fuel cell with a CGO-based electrolyte plotted against electrical power density at a range of fuel dilutions
  • FIG. 3 schematically shows a fuel cell stack with a control system for controlling one or more operating conditions of the fuel cell stack dependent upon a required power output;
  • FIG. 4 schematically shows a Solid Oxide Fuel Cell system operating on LPG flue
  • FIG. 5 shows the stack (DC) and system (AC) power outputs during simulations of the system shown in FIG. 4 ;
  • FIG. 6 shows the stack temperature during the simulations
  • FIG. 7 shows the stoichiometric air ratio during the simulations
  • FIG. 8 shows the resulting stack and system efficiencies during the simulations
  • FIG. 9 shows the ionic and external currents within the stack during the simulations
  • FIG. 10 shows the predicted voltage of a single fuel cell
  • FIG. 11 shows the steam/carbon ration in the reformer for a further simulation
  • FIG. 12 shows the stack efficiency for the further simulation.
  • FIG. 1 illustrates the results of a computer simulation of a CGO-based fuel cell with a nominal maximum specific power output of 0.2 Wcm ⁇ 2 .
  • Energy conversion efficiency is plotted against electrical power density at a range of operating temperatures from 500° C. to 600° C.
  • the energy conversion efficiency is defined as the electrical power output divided by the chemical energy in the hydrogen fuel consumed, assuming 100% fuel conversion.
  • a clear strategy for optimising the efficiency of a stack with these characteristics is therefore to allow the stack temperature to vary in the range 500-600° C., or possibly up to 650° C. depending upon the required power output. This is relatively simple to achieve since a higher electrical power output from the stack also results in a higher heat output, and by under-cooling the stack, the temperature can easily be allowed to rise with an increased power output, and vice-versa.
  • the stack may not be at a high enough temperature to enable that demand to be met.
  • the stack may be heated, it may be possible, if required, to cover this demand temporarily using some form of energy storage.
  • FIG. 2 illustrates the results of another computer simulation of a CGO-based cell, this time with a nominal maximum power density of 0.4 Wcm ⁇ 2 .
  • the temperature was kept constant at 570° C., and the dilution of the hydrogen fuel with steam was varied.
  • diluting the fuel with increasing percentages of steam has much the same effect as reducing the temperature. This is largely because the addition of higher percentages of steam to the hydrogen fuel makes the fuel less reducing. This has the effect of lessening the tendency of Ce 4+ ions in the electrolyte to reduce to Ce 3+ , and thus reduces the electronic conductivity of the electrolyte.
  • diluting the fuel also increases the anode resistance and reduces the cell open-circuit voltage, thus reducing the maximum power output achievable.
  • Another possible strategy to optimise the stack efficiency at part-load is to dilute the fuel with an increasing percentage of steam as the load falls. This method is equally applicable if the fuel is diluted with carbon dioxide, nitrogen, or a mixture of steam, nitrogen and/or carbon dioxide, or if the fuel gas is carbon monoxide, or a mixture of hydrogen and carbon monoxide.
  • a method of achieving this fuel dilution would be to mix the incoming fuel gas with a variable proportion of recycled exhaust gas from the anode side of the stack.
  • any method of diluting the anode fuel gas for example by supplying steam, nitrogen and/or carbon dioxide from a separate source would fall within the scope of the present invention.
  • FIG. 3 schematically shows a solid oxide fuel cell stack with Led ionic/electronic conducting electrolytes with a control system for controlling at least one of the temperatures of the fuel cell stack and/or the dilution of the fuel delivered to the stack.
  • Fuel cell stack 10 has an anode compartment 11 through which a hydrogen-containing fuel gas is passed, and a cathode compartment 12 through which air is passed.
  • the fuel cell stack is made up of single or multiple arrangements of anode, electrolyte and cathode arranged in layers to achieve a functioning fuel cell stack.
  • the stack has a fuel inlet 30 , through which either hydrogen or a hydrocarbon fuel such as methane is passed, and an outlet conduit 70 through which anode compartment exhaust gases leave the stack. These exhaust gases are typically a mixture of steam and unreacted hydrogen. If the original fuel was a hydrocarbon, the exhaust gases will also contain carbon oxides.
  • a recycle conduit 40 is provided which enables exhaust gases to be mixed with the incoming fuel, by means of a variable compressor 50 . This compressor could either be an electrically driven blower or some form of ejector or jet pump.
  • the mixture of incoming fuel and recycled exhaust gases may be fed to a reformer unit 31 , which converts a hydrocarbon fuel to a mixture of hydrogen and carbon oxides by reaction with steam.
  • the stack is also provided with an air inlet conduit 20 , by which preheated air is fed to the stack, both as an oxidant and coolant.
  • the pre-heating can occur by means that include using excess heat from the fuel cell stack, or recovering heat from the stack exhaust conduits, or using a separate heat source such as induction heating, burning or recovering heat from another external process.
  • the cathode compartment also has an outlet conduit 71 to allow the exhaust gases to be removed from the stack.
  • a microprocessor 60 is provided which may be part of a computer or printed circuit board for example.
  • the microprocessor receives inputs from the stack temperature 13 , the stack voltage 14 and the stack current 15 .
  • the microprocessor is arranged to control the stack temperature via control line 21 , and the ratio of fresh fuel to recycled exhaust gas via control line 51 , which controls the variable compressor 50 .
  • the dilution of the incoming fuel may be controlled by the addition of a controlled amount of steam, carbon dioxide or an inert gas from another source.
  • the control of the stack temperature via line 21 may be effected by a number of methods, or combinations of methods, including but not limited to:
  • the microprocessor receives an input of the power output of the stack by multiplying the stack voltage and current signals 14 and 15 .
  • the microprocessor will contain a look-up table or similar which will contain the optimum stack temperature and/or fuel dilution for a given power output.
  • the microprocessor will manipulate control variables 21 and 51 to attempt to achieve this optimum for a given power output.
  • FIG. 4 schematically illustrates a complete Solid Oxide Fuel Cell system operating on liquid petroleum gas (LPG) fuel.
  • LPG liquid petroleum gas
  • This system illustrates how a method of controlling an intermediate-temperature solid oxide fuel cell (IT-SOFC) stack described in method 1 could be implemented in practice.
  • This system is illustrated as an example only, and many other configurations could be adopted which would achieve the same result.
  • LPG fuel is supplied through some form of mass flow control and desulphurising system 10 .
  • the fuel is mixed with steam from pipe 62 in mixer 21 , at a ratio of at least two moles of steam for every mole of carbon in the fuel.
  • the steam/LPG mixture is then preheated to around 430° C. in the fuel heat exchanger 22 , and then fed to the reformer 23 .
  • the mixture is heated to around 700° C. by means of heat exchange with the exhaust gas stream, which is illustrated schematically by connection 51 from heat exchanger 50 .
  • the hydrocarbons in the fuel predominantly propane with a small fraction of butane, propylene and trace components such as pentane
  • This reformate mixture would typically be 60-70% hydrogen by volume, with a lower percentage of steam, carbon monoxide, carbon dioxide and methane.
  • This gas mixture is suitable for fuelling an SOFC stack without further treatment.
  • the reformate mixture is cooled to a temperature suitable for feeding to the stack by means of the fuel heat exchanger 22 , heating the incoming reactants in the process.
  • the reformate mixture is then fed to the anode compartment 31 of the fuel cell stack 30 by means of the fuel inlet conduit 24 .
  • the fuel gas is partially consumed within the stack, and exhaust gas leaves the anode compartment of the stack by means of the exhaust conduit 41 .
  • the exhaust gas leaves at close to the temperature of the hottest part of the stack, typically 550-620° C. depending on the operating condition.
  • the exhaust gas is predominantly steam and carbon dioxide, with smaller amounts of unburned hydrogen and carbon monoxide.
  • Atmospheric air is drawn into the system through air filter 90 , by air blower 91 .
  • the blower 91 has a variable speed motor controlled by motor controller 93 , and by this means the mass-flow of air drawn into the system can be varied.
  • the mass flow of air being drawn into the system is measured by mass flow sensor 94 .
  • the air is provided both as an oxidant and as a means of cooling the SOFC stack, as it is normal for considerably more air to be fed than that required as an oxidant, the remainder carrying excess heat out of the stack.
  • the air is fed from the mass flow sensor 94 to the air preheater 70 , where it is preheated to a temperature suitable to be fed into the stack (typically 450-500° C.).
  • the incoming air is preheated by cooling the hot exhaust gas stream 63 .
  • the preheated air is then fed to the cathode compartment 32 of the fuel cell stack 30 by means of air conduit 72 .
  • the oxygen in the air is partially consumed by the fuel cell reaction.
  • the residual air, somewhat depleted of oxygen leaves the stack by means of air exhaust conduit 42 .
  • the air will typically be at close to the maximum stack temperature, typically 550-620° C. depending on the operating condition.
  • Both the air and fuel exhaust conduits 41 and 42 feed into the system afterburner 40 , in which the air and fuel exhaust streams are mixed together, and the unreacted hydrogen and carbon monoxide from the stack exhaust are burned conventionally to generate heat.
  • the resulting hot (typically 700-900° C.) exhaust gas stream 43 is first fed through heat exchanger 50 to provide heat for the reformer 23 .
  • the cooler gas stream 52 from heat exchanger 50 is then fed to steam generator 60 , in which it is used to evaporate water supplied by feed pump 61 .
  • the resulting steam is then fed to the reformer via pipe 62 .
  • the exhaust gas, now cooled to around 600° C., is then fed to the air preheater 70 to preheat the incoming air.
  • Finally the exhaust gas, still at around 250° C., is fed to heat exchanger 80 which can be used to recover waste heat for a combined heat and power application.
  • the stack is provided with an external power demand 110 , which draws current off the stack via cable 111 .
  • the nature of the power demand could be one of a range of different applications.
  • the system is provided with a microprocessor based control unit 100 .
  • This measures the stack current via input 101 , and the stack temperature via input 102 . It also measures the mass flow of air entering the system via the mass-flow sensor 94 and input 104 .
  • the control unit controls the air blower 91 by means of the motor controller 93 and output 103 . In this way the controller cat control the air flow to the stack.
  • the control unit 100 also controls the water feed pump 61 by output 105 . In this way the ratio of steam to fuel in the reformer can also be changed.
  • the performance of the system illustrated in FIG. 4 has been simulated on a computer.
  • the system simulated is based on a stack with a power output of 1 kW e , and a system supplying AC power.
  • the AC power output of the system is always less than the stack power output because various parts of the system such as the air blower consume power.
  • FIG. 5 shows the stack (DC) and system (AC) power outputs during the simulations, illustrating the ramping down of power from 800 to 400 W e .
  • FIG. 6 shows the stack temperature during the simulation, and FIG. 7 the stoichiometric air ratio. This represents the ratio of the actual air-flow to the theoretical air demand to supply enough oxygen for the fuel cell reaction. It can be seen that at full power this ratio is around 10, representing the large amount of air required for stack cooling. The air ratio then increases to a maximum of around 20 as the air flow is increased to cool the stack down. The increase in air flow at around 1100 s is as a result of the stack temperature controller being reset to make it more sensitive as the stack temperature nears the new setpoint.
  • FIG. 8 shows the resulting stack and system efficiencies. It can be seen that with the stack temperature maintained at around 590° C., there is a significant fall in efficiency as the load is reduced. This is as a result of increasing electronic conductivity in the electrolyte as the current-density is reduced. However, as the stack temperature falls the efficiency recovers until it is comparable with the full-load efficiency. In fact the stack efficiency is better than the full load efficiency as a result of the higher cell voltage. However the system efficiency is a little worse as a result of fixed parasitic power demands such as that required to run the control system.
  • FIG. 9 shows the ionic and external currents within the stack.
  • the external current is the current flowing in the external circuit
  • the ionic current is the sum of the external current and the electronic leakage current. It can be seen that the gap between these two lines, representing the magnitude of the electronic leak, increases as the external current falls. However, it can also be seen that the gap closes as the stack temperature falls under part-load conditions.
  • FIG. 10 shows the predicted voltage of a single fuel cell. It can be seen that the cell voltage increases as the load is reduced, as would be expected. It can also be seen that the cell voltage actually falls a little as the stack cools, which would normally represent a loss of efficiency as the cell resistance increases. However, the benefit of reducing the leakage current outweighs the increase in resistance provided the temperature fall is not too large.
  • the effect on the stack efficiency can be seen in FIG. 12 .
  • the benefit of his approach is less marked than changing the stack temperature (method 1), but a small improvement in efficiency is clearly apparent.
  • microprocessor may just control the stack temperature but not the fuel dilution, or vice-versa.

Landscapes

  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Sustainable Energy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Fuel Cell (AREA)
US10/588,897 2004-02-10 2005-02-02 Method an apparatus for operating a solid-oxide fuel cell stack with a mixed ionic/electronic conducting electrolyte Abandoned US20100028732A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US13/898,417 US20130260269A1 (en) 2004-02-10 2013-05-20 Method and apparatus for operating a solid-oxide fuel cell stack with a mixed ionic/electronic conducting electrolyte
US15/640,333 US10283792B2 (en) 2004-02-10 2017-06-30 Method and apparatus for operating a solid-oxide fuel cell stack with a mixed ionic/electronic conducting electrolyte

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB0402906.2 2004-02-10
GB0402906A GB2411043B (en) 2004-02-10 2004-02-10 A method and apparatus for operating an intermediate-temperature solid-oxide fuel cell stack
PCT/GB2005/000355 WO2005078843A1 (fr) 2004-02-10 2005-02-02 Procede et dispositif pour le fonctionnement d'un assemblage de piles a combustible a oxyde solide avec un electrolyte a conduction mixte ionique/electronique

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2005/000355 A-371-Of-International WO2005078843A1 (fr) 2004-02-10 2005-02-02 Procede et dispositif pour le fonctionnement d'un assemblage de piles a combustible a oxyde solide avec un electrolyte a conduction mixte ionique/electronique

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US13/898,417 Continuation US20130260269A1 (en) 2004-02-10 2013-05-20 Method and apparatus for operating a solid-oxide fuel cell stack with a mixed ionic/electronic conducting electrolyte

Publications (1)

Publication Number Publication Date
US20100028732A1 true US20100028732A1 (en) 2010-02-04

Family

ID=32011639

Family Applications (3)

Application Number Title Priority Date Filing Date
US10/588,897 Abandoned US20100028732A1 (en) 2004-02-10 2005-02-02 Method an apparatus for operating a solid-oxide fuel cell stack with a mixed ionic/electronic conducting electrolyte
US13/898,417 Abandoned US20130260269A1 (en) 2004-02-10 2013-05-20 Method and apparatus for operating a solid-oxide fuel cell stack with a mixed ionic/electronic conducting electrolyte
US15/640,333 Active 2025-05-26 US10283792B2 (en) 2004-02-10 2017-06-30 Method and apparatus for operating a solid-oxide fuel cell stack with a mixed ionic/electronic conducting electrolyte

Family Applications After (2)

Application Number Title Priority Date Filing Date
US13/898,417 Abandoned US20130260269A1 (en) 2004-02-10 2013-05-20 Method and apparatus for operating a solid-oxide fuel cell stack with a mixed ionic/electronic conducting electrolyte
US15/640,333 Active 2025-05-26 US10283792B2 (en) 2004-02-10 2017-06-30 Method and apparatus for operating a solid-oxide fuel cell stack with a mixed ionic/electronic conducting electrolyte

Country Status (20)

Country Link
US (3) US20100028732A1 (fr)
EP (1) EP1716612B1 (fr)
JP (4) JP2007522643A (fr)
KR (1) KR101097494B1 (fr)
CN (1) CN100536213C (fr)
AU (1) AU2005212911B2 (fr)
BR (1) BRPI0507602B1 (fr)
CA (1) CA2555943C (fr)
DK (1) DK1716612T3 (fr)
EA (1) EA010368B1 (fr)
ES (1) ES2388925T3 (fr)
GB (1) GB2411043B (fr)
HK (1) HK1095922A1 (fr)
IL (1) IL177420A0 (fr)
MX (1) MXPA06009155A (fr)
NZ (1) NZ549220A (fr)
PL (1) PL1716612T3 (fr)
PT (1) PT1716612E (fr)
WO (1) WO2005078843A1 (fr)
ZA (1) ZA200607517B (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012018297A1 (fr) * 2010-08-02 2012-02-09 Gettfuelcells International Ab Pile à combustible
US20130209286A1 (en) * 2012-02-15 2013-08-15 Korea Institute Of Science And Technology Hydrogen pump system operable without external electric power supply
US20130260272A1 (en) * 2010-12-20 2013-10-03 Toyota Jidosha Kabushiki Kaisha Fuel cell system and fuel cell system diagnosis method

Families Citing this family (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100788194B1 (ko) * 2006-05-25 2007-12-26 엘지전자 주식회사 연료전지시스템
WO2008003976A1 (fr) 2006-07-07 2008-01-10 Ceres Intellectual Property Company Limited substrat métallique pour des piles à combustible
JP5037214B2 (ja) * 2007-05-01 2012-09-26 Ｊｘ日鉱日石エネルギー株式会社 改質器システム、燃料電池システム、及びその運転方法
GB2461115A (en) 2008-04-23 2009-12-30 Ceres Power Ltd Fuel Cell Module Support
BRPI0917632A2 (pt) 2008-08-21 2017-07-11 Ceres Ip Co Ltd Aperfeiçoamento para escoamento de ar em anteparo de escoamento em compartimentos de combustível empilhados com emprego de um dispositivo de distribuição de ar
US9005833B2 (en) * 2010-04-09 2015-04-14 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. System having high-temperature fuel cells
EP2669980A4 (fr) * 2011-01-24 2016-03-23 Nissan Motor Système de génération de puissance d'une pile à combustible et procédé de commande d'un tel système
ITVR20110109A1 (it) 2011-05-19 2012-11-20 Stefano Cavalli Metodo di controllo e massimizzazione dell?efficienza elettrica e della produzione di potenza di una pila a combustibile - method of controlling and maximizing the electric efficiency and the power output of a fuel cell
JP6303282B2 (ja) * 2013-04-11 2018-04-04 日産自動車株式会社 燃料電池発電システム
GB201312329D0 (en) 2013-07-09 2013-08-21 Ceres Ip Co Ltd Improved fuel cell systems and methods
WO2015136295A1 (fr) 2014-03-12 2015-09-17 Ceres Intellectual Property Company Limited Agencement de bloc de piles à combustible
GB2534124B (en) 2014-12-19 2017-04-19 Ceres Ip Co Ltd A swirl burner assembly and method
US11527766B2 (en) 2014-12-19 2022-12-13 Ceres Intellectual Property Company Limited Fuel cell system and tail gas burner assembly and method
JP6843531B2 (ja) * 2016-06-27 2021-03-17 三菱パワー株式会社 燃料電池の制御装置及び制御方法並びに発電システム
GB2563848B (en) 2017-06-26 2022-01-12 Ceres Ip Co Ltd Fuel cell stack assembly
GB201913907D0 (en) 2019-09-26 2019-11-13 Ceres Ip Co Ltd Fuel cell stack assembly apparatus and method
GB201915294D0 (en) 2019-10-22 2019-12-04 Ceres Ip Co Ltd Alignment apparatus and methods of alignment
GB201915438D0 (en) 2019-10-24 2019-12-11 Ceres Ip Co Ltd Metal-supported cell unit
US11777126B2 (en) * 2019-12-05 2023-10-03 Utility Global, Inc. Methods of making and using an oxide ion conducting membrane
GB2591462B (en) 2020-01-27 2022-04-20 Ceres Ip Co Ltd Interlayer for solid oxide cell
DE102020202873A1 (de) * 2020-03-06 2021-09-09 Robert Bosch Gesellschaft mit beschränkter Haftung Verfahren zur Überwachung eines Brennstoffzellensystems
GB202009687D0 (en) 2020-06-25 2020-08-12 Ceres Ip Co Ltd Layer
AU2022381461A1 (en) 2021-11-08 2024-05-02 Rhodia Operations Cerium-gadolinium composite oxide
WO2023078944A1 (fr) 2021-11-08 2023-05-11 Rhodia Operations Oxyde composite de cérium et de gadolinium

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030012996A1 (en) * 2001-06-26 2003-01-16 Stefan Bitterlich Fuel cell

Family Cites Families (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58112262A (ja) * 1981-12-25 1983-07-04 Toshiba Corp 燃料電池の温度制御装置
JPH0665054B2 (ja) * 1983-10-05 1994-08-22 三洋電機株式会社 空冷式燃料電池
JP3160993B2 (ja) * 1992-02-20 2001-04-25 松下電器産業株式会社 固体電解質型燃料電池
US5366821A (en) 1992-03-13 1994-11-22 Ballard Power Systems Inc. Constant voltage fuel cell with improved reactant supply and control system
US5346778A (en) 1992-08-13 1994-09-13 Energy Partners, Inc. Electrochemical load management system for transportation applications
AU5634896A (en) * 1996-05-01 1997-11-19 Gas Research Institute, Inc. Stable high conductivity functionally gradient compositionally layered solid state electrolytes and membranes
NL1004513C2 (nl) * 1996-11-13 1998-05-29 Stichting Energie Serie geschakeld brandstofcelstelsel.
JP3680232B2 (ja) * 1997-03-31 2005-08-10 トヨタ自動車株式会社 固体電解質と、これを用いた燃料電池、水素ポンプ、酸素濃度センサおよび水蒸気濃度センサ
US6844098B1 (en) * 1997-08-29 2005-01-18 Mitsubishi Materials Corporation Oxide-ion conductor and use thereof
SE514689C2 (sv) * 1998-06-12 2001-04-02 Bin Zhu Bränslecell
US6139985A (en) * 1998-07-24 2000-10-31 Siemens Westinghouse Power Corporation Electrode electrolyte interlayers containing cerium oxide for electrochemical fuel cells
DE19952384A1 (de) 1999-10-30 2001-05-17 Forschungszentrum Juelich Gmbh Optimierung der Betriebsparameter eines Direkt-Methanol-Brennstoffzellensystems
JP4934248B2 (ja) 2001-05-23 2012-05-16 パナソニック株式会社 電力生成制御システム、および燃料電池システム
KR100511355B1 (ko) 2000-10-03 2005-08-31 마츠시타 덴끼 산교 가부시키가이샤 전력생성 제어시스템, 전력생성 제어방법, 컴퓨터 프로그램 제품 및 매체
US6803141B2 (en) 2001-03-08 2004-10-12 The Regents Of The University Of California High power density solid oxide fuel cells
JP3822139B2 (ja) * 2001-06-28 2006-09-13 本田技研工業株式会社 燃料電池電源装置
JP2003115315A (ja) * 2001-10-05 2003-04-18 Nippon Steel Corp 固体電解質型燃料電池の運転方法
JP4022095B2 (ja) * 2002-04-30 2007-12-12 三菱重工業株式会社 燃料電池モジュール及び燃料電池モジュールの起動方法
JP2003331885A (ja) * 2002-05-17 2003-11-21 Daihatsu Motor Co Ltd 燃料電池装置
AUPS244802A0 (en) * 2002-05-21 2002-06-13 Ceramic Fuel Cells Limited Fuel cell system
JP3949512B2 (ja) * 2002-05-27 2007-07-25 独立行政法人科学技術振興機構 アノード支持固体酸化物型燃料電池の製造方法
GB0213561D0 (en) 2002-06-13 2002-07-24 Alstom Fuel cells
GB2405028B (en) * 2003-08-14 2006-03-08 Ceres Power Ltd Method and device for operating an intermediate temperature solid oxide fuel cell.

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030012996A1 (en) * 2001-06-26 2003-01-16 Stefan Bitterlich Fuel cell

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012018297A1 (fr) * 2010-08-02 2012-02-09 Gettfuelcells International Ab Pile à combustible
US20130260272A1 (en) * 2010-12-20 2013-10-03 Toyota Jidosha Kabushiki Kaisha Fuel cell system and fuel cell system diagnosis method
US9178231B2 (en) * 2010-12-20 2015-11-03 Toyota Jidosha Kabushiki Kaisha Fuel cell system and fuel cell system diagnosis method
US20130209286A1 (en) * 2012-02-15 2013-08-15 Korea Institute Of Science And Technology Hydrogen pump system operable without external electric power supply

Also Published As

Publication number Publication date
GB2411043B (en) 2007-09-19
GB0402906D0 (en) 2004-03-17
BRPI0507602B1 (pt) 2015-08-04
JP2016173989A (ja) 2016-09-29
US20130260269A1 (en) 2013-10-03
AU2005212911A1 (en) 2005-08-25
ZA200607517B (en) 2008-06-25
US10283792B2 (en) 2019-05-07
JP5963840B2 (ja) 2016-08-03
PL1716612T3 (pl) 2012-10-31
MXPA06009155A (es) 2007-03-01
DK1716612T3 (da) 2012-09-17
GB2411043A (en) 2005-08-17
CN1947297A (zh) 2007-04-11
CN100536213C (zh) 2009-09-02
EP1716612B1 (fr) 2012-06-06
WO2005078843A1 (fr) 2005-08-25
AU2005212911B2 (en) 2009-05-21
ES2388925T3 (es) 2012-10-19
PT1716612E (pt) 2012-08-10
CA2555943A1 (fr) 2005-08-25
NZ549220A (en) 2008-04-30
HK1095922A1 (en) 2007-05-18
JP2015084333A (ja) 2015-04-30
CA2555943C (fr) 2011-09-13
EA010368B1 (ru) 2008-08-29
US20170301936A1 (en) 2017-10-19
JP2013058494A (ja) 2013-03-28
IL177420A0 (en) 2006-12-10
KR20070024485A (ko) 2007-03-02
JP2007522643A (ja) 2007-08-09
EA200601446A1 (ru) 2006-12-29
EP1716612A1 (fr) 2006-11-02
KR101097494B1 (ko) 2011-12-22
BRPI0507602A (pt) 2007-07-03

Similar Documents

Publication Publication Date Title
US10283792B2 (en) Method and apparatus for operating a solid-oxide fuel cell stack with a mixed ionic/electronic conducting electrolyte
JP2016173989A5 (fr)
US7846599B2 (en) Method for high temperature fuel cell system start up and shutdown
EP1523056B1 (fr) Centrale hybride comprenant des piles à combustible avec contrôl du flux d'oxydant pour la combustion de combustible usé
US20070178338A1 (en) Fuel cell system with electrochemical anode exhaust recycling
CN1674335A (zh) 综合燃料电池－燃气轮机系统启动和瞬态工作的方法和系统
KR20040057947A (ko) 하이브리드 파워 플랜트
KR20210132169A (ko) 일산화탄소 내성 애노드 및 통합된 시프트 반응기를 구비한 수소 펌핑 전지를 갖는 고체 산화물 연료 전지 시스템
KR102511826B1 (ko) 캐스케이드형 연료 전지를 사용하는 발전 시스템 및 그 연계된 방법
JP4450623B2 (ja) 燃料電池システム
US20080292922A1 (en) Method and apparatus for fueling a solid oxide fuel cell stack assembly
JP2014089920A (ja) 固体酸化物形燃料電池システム
JP2020061268A (ja) 固体酸化物形燃料電池システム
JP2004247247A (ja) 固体酸化物形燃料電池システム
WO2022113397A1 (fr) Système de pile à combustible
CN118054036A (zh) 包括蒸汽再循环和阴极排气冷却器的电化学电池系统
WO2023126625A1 (fr) Système de pile à combustible
JPH01112671A (ja) 燃料電池発電プラントの運転方法及び燃料電池発電プラント
CN118117114A (zh) 一种混合燃料电池热电联供系统及运行方法
Atkinson et al. Fuel Cells for Autonomous Vehicles
JP2003109644A (ja) 燃料電池の発電方法及び燃料電池システム

Legal Events

Date Code Title Description
AS Assignment

Owner name: CERES POWER LIMITED,UNITED KINGDOM

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:LEAH, ROBERT;BRANDON, NIGEL PETER;DUCKETT, ATHOL;AND OTHERS;SIGNING DATES FROM 20061121 TO 20061127;REEL/FRAME:021730/0702

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION