CA2253564A1 - High-temperature fuel cell plant and process for operating the same - Google Patents
High-temperature fuel cell plant and process for operating the same Download PDFInfo
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- CA2253564A1 CA2253564A1 CA002253564A CA2253564A CA2253564A1 CA 2253564 A1 CA2253564 A1 CA 2253564A1 CA 002253564 A CA002253564 A CA 002253564A CA 2253564 A CA2253564 A CA 2253564A CA 2253564 A1 CA2253564 A1 CA 2253564A1
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- fuel cell
- temperature fuel
- high temperature
- gas
- anode
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- 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
- H01M8/04082—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
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2300/00—Electrolytes
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0065—Solid electrolytes
- H01M2300/0068—Solid electrolytes inorganic
- H01M2300/0071—Oxides
- H01M2300/0074—Ion conductive at high temperature
-
- 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
- H01M8/04119—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying
- H01M8/04156—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying with product water removal
-
- 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
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Fuel Cell (AREA)
Abstract
This invention concerns a process for operating a high-temperature fuel cell plant (2) which consists of at least one high-temperature fuel cell block (4) with an anode element (6) and a cathode element (8), whereby at least a portion of the anode exhaust gas of the high-temperature fuel cell block (4) is fed as fuel to a gas engine (26) connected to a generator (50) to increase the power generated. This measure provides highly efficient and flexible energy production.
Description
- CA 022~3~64 1998-11-0~
GR 96 P 3308 P FILE, ~ TIIIS AMr.~t~
~T TI~QNSLATI~!N
Description Process for operating a high temperature fuel cell installation, and high temperature fuel cell installation The invention relates to a process for operating a high temperature fuel cell installation and to a high temperature fuel cell installation.
It is known that, during the electrolysiE, of water, the water molecules are decomposed by electric current into hydrogen (H2) and oxygen (~2)- In a fuel cell, this process takes place in reverse. Through the electrochemical combination of hydrogen (H2) and oxygen (~2) to form water, electric current is produced with high efficiency. If pure hydrogen (H2) is u~ed a~ combus-tion gas, this takes place without the emission of pollutants and carbon dioxide (C02). Even with a technical combustion gas, for example natural gas or coal gaE,, and with air (which may additionally be enriched with oxygen (~2) ) instead of pure oxygen (~2) ~ a fuel cell produces conRiderably less pollutants and less carbon dioxide (C02) than other forms of energy production which operate using fossil energy sources.
The technical implementation of the fuel cell principle has given rise to a variety of solutions, and more precisely with different electrolytes and with operating temperatures of between 80 ~C and 1000~C.
CA 022~3564 1998-11-0 Depen~;ng on their operating temperature, fuel cells are divided into low, medium and high temperature fuel cells, which in turn differ through various technical embodiments.
5A high temperature fuel cell block (a fuel cell block is also referred to a "stack" in the specialist literature) is generally composed of a multitude of high temperature fuel cells which are of planar construction and are stacked on one another. Fuel cell installations comprising at least one high temperature fuel cell block are, for example, known from the German Patent Applica-tions with the official reference nl~hers 195 23 973.3, 195 23 972.5 and 195 14 469.4.
A high temperature fuel cell installation is operated with a high constant operating temperature of, for example, in excess of 900~C. For this purpose, in order to achieve the operating temperature before opera-tion or to hold the required operating temperature during brief interruptions to operation, the installation must be supplied with additional heat.
A further problem is to use the working medium efficiently during operation of the high temperature fuel cell block. In order to make it possible to operate the high temperature fuel cell block with high efficiency, the working medium needs to be supplied in exceRs. Only through an excess of working medium is it possible to guarantee that the active faces of the high temperature fuel cells are provided with enough working medium. An unavoidable consequence . . .
CA 022~3~64 1998-11-0 of operating the high temperature fuel cell block with excess working medium is that, after the electrochemical reaction has taken place, there is still some working medium present in the off-gas at the outlet of the high temperature fuel cell block. Put another way, the working medium is not fully consumed in the high temperature fuel cell block. Some of it emerges unused, and this impairs efficiency.
Laid-open German Patent Specification 41 37 968 discloses a heat ~YchAnge device in which the off-gas from a high temperature fuel cell block is fed to an ~YpAn~ion turbine. In this case, the off-gas from the high temperature fuel cell block contains unconsumed air from the cathode off-gas and unconsumed hydrogen from the anode off-gas. In order to heat the off-gas to the input temperature of the expansion turbine, the off-ga~ is fed before feeding through a heat eYchAnger integrated in the high temperature fuel cell block. After having been fed into the turbine, the off-gas is expanded therein. This means that only the heat content of the off-gas is used for the production of energy in the turbine, but not actually the components of the off-gas, for example hydrogen.
The object of the invention is to provide a process for operating a high temperature fuel cell installation, in which efficient and flexible energy production is guaranteed. A further object is to provide a high temperature fuel cell in~tallation having high efficiency.
CA 022~3~64 1998-11-0 The former object is achieved according to the invention by a process for operating a high temperature fuel cell installation comprising at least one high temperature fuel cell block with an anode part and a cathode part. In order to increase the energy production, a gas motor coupled to a generator is provided, the motor being fed at least a portion of the anode off-gas from the high temperature fuel cell block.
This process proves efficient since all of the working medium, unless consumed in the fuel cell block and therefore not present in the anode off-gas, is available to the gas motor as working medium for obtaining further energy. At the same time, the process proves flexible since the gas motor does not always need to be provided with the same amount of working medium from the anode off-gas at every operating time. If, at a particular operating time, there is not enough working medium in the anode off-gas to operate the gas motor, then the missing portion of working medium can be fed separately to the gas motor.
Preferably, water is withdrawn from the anode off-gas before feeding into the gas motor. In other words, the water produced during the electrochemical reaction in the high temperature fuel cell block is withdrawn from the anode off-gas, 80 that the working medium is present in a form which can be exploited by the gas motor. Together with the water, the anode off-gas also has some of its heat content withdrawn. The tempera-ture of the anode off-gas, that is to say the working medium for the gas CA 022~3~64 l998-ll-0 motor is therefore reduced on the way from the high temperature fuel cell block to the gas motor.
In particular, a working medium for the anode part may be supplied with water in the form of water 5 vapor before the feeding.
In a further refinement, a portion of the electric current produced with the generator is used to heat a working medium when the high temperature fuel cell block is being started up. For example, the working medium provided for the high temperature fuel cell block in normal operation may at the start be fed directly via a bypass to the gas motor, the energy of which is there-fore used for electrically heating the high temperature fuel cell block. The high temperature fuel cell block may 15 consequently be started up with the gas motor, which forms part of the overall high temperature fuel cell installation.
In particular, a working medium for the anode part and/or cathode part of the high temperature fuel cell block may be heated with the heat dissipated by the gas motor.
The latter object is achieved according to the invention by a high temperature fuel cell installation having at least one high temperature fuel cell block comprising an anode part and a cathode part. In order to increase the energy production, a gas motor coupled to a generator is provided, the gas motor being connected to the discharge path of the anode part of the high tempera-ture fuel cell block.
CA 022~3~64 1998-11-0 Preferably, at least one water precipitator is provided in the discharge path of the anode part. The water removed from the anode off-gas by at least one water precipitator may, for example, be fed via a feed water tank to a steam generator, the water subsequently evaporated being fed back to the working medium for the anode part of the high temperature fuel cell block. ~y virtue of this, even the water from the anode off-gas can be fed for reuse in the high temperature fuel cell block.
In particular, at least one heat e~ch~nger may be arranged in the discharge line of the gas motor.
In a further refinement, a steam generator i8 provided in the discharge line of the gas motor. Using the ~team generator, the water from the off-gas of the anode part of the high temperature fuel cell block is evaporated for reuse in the cathode part.
Preferably, the generator is connected to a heating device arranged in the feed path of the cathode part. A fraction of the electric current produced in the generator is used to heat the working medium for the cathode part.
In particular, the generator may be connected to an electrical network in order to feed it with electric current. The current may be fed to a load via the electrical network.
For further explanation of the invention, reference will be made to the illustrative embodiment in the drawing, the single , .
- CA 022~3~64 lgss-ll-o~
figure of which schematically represents a high tempera-ture fuel cell installation.
According to the figure, a high temperature fuel cell installation 2 comprises a high temperature fuel cell block 4 which is divided into an anode part 6 with anode gas spaces (not shown in detail) and a cathode part 8 with cathode gas spaces (not further shown). The high temperature fuel cell block 4 is preferably composed of a multitude of high temperature fuel cells (not further shown) of planar design.
An invertor 10, which converts the direct current produced by the high temperature fuel cell block 4 into alternating current for an electrical network 18, is connected to the high temperature fuel cell block 4.
The anode part 6 is assigned an anode path 12 for supplying it with a working medium, for example hydrogen (H2) or a mixture of combustion gas and reaction vapor, this anode path 12 comprising a feed path 14 and a discharge path 16. Before feeding into the anode part 6, the working medium is referred to as "working medium for the anode part 6", and after it has left the anode part 6, it is referred to as "anode off-gas of the anode part 6".
A gas splitter 20, a mixing chamber 22 and a heat eYchAnger 24 are successively arranged, in that order in the flow direction, in the feed path 14 of the anode part 6 of the high temperature fuel cell block 4. A gas motor 26 is connected to the discharge path 16 of the anode part 6 of the , .
- CA 022~3~64 1998-ll-0 high temperature fuel cell block 4. The term "gas motor"
is in this context intended to mean a device for converting the chemical energy contained in the working medium (anode off-gas) into mechanical energy. A
generator 50, which converts the mechanical energy produced in the gas motor 26 into alternating current, i8 coupled to the gas motor 26. The alternating current is delivered to an electrical network 54 via a line 52.
The off-gas from the gas motor 26 is discharged by a discharge line 17 from the high temperature fuel cell installation 2. A heat ~Yrhanger 36, a steam generator 38 and a further heat ~X~hAnger 40 are successively arranged, in that order in the flow direction, in the discharge line 17.
Two water precipitators 30, 32 and a mixing chamber 34 are successively arranged, in that order in the flow direction, in the discharge path 16 of the anode part 6.
The working medium for the anode part 6 is fed into the anode part 6 of the high temperature fuel cell block 4 via the feed path 14. This being the case, the working medium firstly flows through the ga~ splitter 20, in which a fraction of the working medium is diverted from the feed path 14 via a line 44 and fed directly into the mixing chamber 34 arranged upstream of the gas motor 26 in the discharge path 16 of the anode part 6.
Operation of the gas motor 26 is therefore guaranteed even if not enough working medium is present in the anode off-gas of the anode part 6 of the high temperature fuel cell block 4. In the heat eYc-h~nger 24, the working CA 022~3~64 1998-11-0 medium for the anode part 6 i~ heated by the anode off-gas.
After the electrochemical reaction has taken place in the high temperature fuel cell block 4, the anode off-gas is discharged from the high temperature fuel cell block 4 via the discharge path 16. In the water precipitators 30 and 32, a large portion of the process water produced during the reaction in the high tempera-ture fuel cell block 4 is removed together with a fraction of the heat content of the anode off-gas.
After the procens water has been removed from the anode off-gas, the cooled anode off-gas passes as working medium via the ~;Y; ng chamber 34 into the gas motor 26.
In the latter, the working medium, i.e. the anode off-gas, is burnt to produce mechanical energy.
In the steam generator 38, the process waterremoved by the water precipitators 30, 32 from the anode off-gas is evaporated. For this purpose, the process water from the water precipitators 30, 32 is fed to the steam generator 38 via a line 60, in which a feed water tank 62 and a pump 64 are arranged. The feed water tank 62 is in this case used as a reservoir for the process water. The latter is fed in the required quantity to the steam generator 38 by the pump 64.
The water vapor produced in the steam generator 38 is fed via a line 68 to the mixing chamber 22 which is arranged in the feed path 14 of the anode part 6. The water - CA 022~3~64 lgss-ll-o~
vapor is therefore mixed with the working medium for the anode part 6 in order to heat this medium.
The heat obtained in the water precipitator 30 and in the further heat eYchAnger 40 can be fed via a line 120 carrying a heat-exchange medium into a local hot water network 122 (not shown in detail).
The cathode part 8 of the high temperature fuel cell block 4 is assigned a cathode path 80 which comprise~ a feed path 82 and a discharge path 84. A
compressor 86, a gas splitter 88, a ~iY;ng chamber 90, a heat ~YchAnger 92 and an electrical heating device 94 are succes~ively arranged, in that order in the flow direction, in the feed path 82 of the cathode part 8.
The working medium for the cathode part 8 is fed to the cathode part 8 via the feed path 82. This being the case, the working medium, for example air or air enriched with oxygen (~2) ~ i8 fed into the gas splitter 88 via the compre~or 86.
In the gas splitter 88, at lea~t a fraction of the working medium for the cathode part 8 is diverted from the feed path 82 of the cathode part 8 and fed via a line 100 through the heat ~YchAnger 36. It i8 then fed back via the mixing chamber 90 to the feed path 82. Since the heat exchanger 36 is connected downstream of the gas motor 26 in the discharge line 17 for the off-gas from the gas motor 26, the working medium for the cathode part 8 diverted from the feed path 82 is heated by the off-gas from the gas motor 26. The waste heat of the off-gas CA 022~3~64 1998-ll-0 from the gas motor 26 i~ therefore advantageously used to heat the working medium for the cathode part 8.
The undiverted fraction of the working medium passes directly via the line 82 into the ;Y; ng chamber 90, where it is recombined with the diverted fraction.
The working medium for the cathode part 8 is then heated in the heat exchanger 92 and in the electrical heating device 94. In the heat exchanger 92, the working medium for the cathode part 8 is heated by the cathode off-gas, and in the electrical heating device 94 it is electrically heated for starting up the high temperature fuel cell block 4. In this case, the electrical heating device 94 is supplied with current from the generator 50 assigned to the gas motor 26. The electrical heating device 94 is in this case supplied with current via a line 102 from the line 52.
The cathode off-gas i8 firstly fed via the discharge path 84 of the cathode path 8 through the heat ~YrhAnger 92, where it heats the working medium for the cathode part 8. It i8 then fed to a local heat-using system 110 (not shown in detail).
On the one hand, therefore, the gas motor 26 is operated using the anode off-ga~ from the high temperature fuel cell block 4 and on the other hand the gas motor 26 is used for starting up the high temperature fuel cell block 4. The process water obtained during the electrochemical reaction in the high temperature fuel cell block 4 is fed in the form of water vapor to the .
- CA 022~3~64 lsss-ll-o~
working medium for the anode part 6 in order to heat it.
Further, the current produced by the gas motor 26 and the generator 50 is used to operate the electrical heating device 94 for heating the working medium for the cathode part 8 of the high temperature fuel cell block 4. In addition, the heat of the off-gas from the gas motor 26 preheats the working medium for the cathode part 8 of the high temperature fuel cell block 4.
It i8 therefore possible for the etart-up process of the high temperature fuel cell installation 2 to be carried out merely using components which are provided in the high temperature fuel cell installation 2.
GR 96 P 3308 P FILE, ~ TIIIS AMr.~t~
~T TI~QNSLATI~!N
Description Process for operating a high temperature fuel cell installation, and high temperature fuel cell installation The invention relates to a process for operating a high temperature fuel cell installation and to a high temperature fuel cell installation.
It is known that, during the electrolysiE, of water, the water molecules are decomposed by electric current into hydrogen (H2) and oxygen (~2)- In a fuel cell, this process takes place in reverse. Through the electrochemical combination of hydrogen (H2) and oxygen (~2) to form water, electric current is produced with high efficiency. If pure hydrogen (H2) is u~ed a~ combus-tion gas, this takes place without the emission of pollutants and carbon dioxide (C02). Even with a technical combustion gas, for example natural gas or coal gaE,, and with air (which may additionally be enriched with oxygen (~2) ) instead of pure oxygen (~2) ~ a fuel cell produces conRiderably less pollutants and less carbon dioxide (C02) than other forms of energy production which operate using fossil energy sources.
The technical implementation of the fuel cell principle has given rise to a variety of solutions, and more precisely with different electrolytes and with operating temperatures of between 80 ~C and 1000~C.
CA 022~3564 1998-11-0 Depen~;ng on their operating temperature, fuel cells are divided into low, medium and high temperature fuel cells, which in turn differ through various technical embodiments.
5A high temperature fuel cell block (a fuel cell block is also referred to a "stack" in the specialist literature) is generally composed of a multitude of high temperature fuel cells which are of planar construction and are stacked on one another. Fuel cell installations comprising at least one high temperature fuel cell block are, for example, known from the German Patent Applica-tions with the official reference nl~hers 195 23 973.3, 195 23 972.5 and 195 14 469.4.
A high temperature fuel cell installation is operated with a high constant operating temperature of, for example, in excess of 900~C. For this purpose, in order to achieve the operating temperature before opera-tion or to hold the required operating temperature during brief interruptions to operation, the installation must be supplied with additional heat.
A further problem is to use the working medium efficiently during operation of the high temperature fuel cell block. In order to make it possible to operate the high temperature fuel cell block with high efficiency, the working medium needs to be supplied in exceRs. Only through an excess of working medium is it possible to guarantee that the active faces of the high temperature fuel cells are provided with enough working medium. An unavoidable consequence . . .
CA 022~3~64 1998-11-0 of operating the high temperature fuel cell block with excess working medium is that, after the electrochemical reaction has taken place, there is still some working medium present in the off-gas at the outlet of the high temperature fuel cell block. Put another way, the working medium is not fully consumed in the high temperature fuel cell block. Some of it emerges unused, and this impairs efficiency.
Laid-open German Patent Specification 41 37 968 discloses a heat ~YchAnge device in which the off-gas from a high temperature fuel cell block is fed to an ~YpAn~ion turbine. In this case, the off-gas from the high temperature fuel cell block contains unconsumed air from the cathode off-gas and unconsumed hydrogen from the anode off-gas. In order to heat the off-gas to the input temperature of the expansion turbine, the off-ga~ is fed before feeding through a heat eYchAnger integrated in the high temperature fuel cell block. After having been fed into the turbine, the off-gas is expanded therein. This means that only the heat content of the off-gas is used for the production of energy in the turbine, but not actually the components of the off-gas, for example hydrogen.
The object of the invention is to provide a process for operating a high temperature fuel cell installation, in which efficient and flexible energy production is guaranteed. A further object is to provide a high temperature fuel cell in~tallation having high efficiency.
CA 022~3~64 1998-11-0 The former object is achieved according to the invention by a process for operating a high temperature fuel cell installation comprising at least one high temperature fuel cell block with an anode part and a cathode part. In order to increase the energy production, a gas motor coupled to a generator is provided, the motor being fed at least a portion of the anode off-gas from the high temperature fuel cell block.
This process proves efficient since all of the working medium, unless consumed in the fuel cell block and therefore not present in the anode off-gas, is available to the gas motor as working medium for obtaining further energy. At the same time, the process proves flexible since the gas motor does not always need to be provided with the same amount of working medium from the anode off-gas at every operating time. If, at a particular operating time, there is not enough working medium in the anode off-gas to operate the gas motor, then the missing portion of working medium can be fed separately to the gas motor.
Preferably, water is withdrawn from the anode off-gas before feeding into the gas motor. In other words, the water produced during the electrochemical reaction in the high temperature fuel cell block is withdrawn from the anode off-gas, 80 that the working medium is present in a form which can be exploited by the gas motor. Together with the water, the anode off-gas also has some of its heat content withdrawn. The tempera-ture of the anode off-gas, that is to say the working medium for the gas CA 022~3~64 l998-ll-0 motor is therefore reduced on the way from the high temperature fuel cell block to the gas motor.
In particular, a working medium for the anode part may be supplied with water in the form of water 5 vapor before the feeding.
In a further refinement, a portion of the electric current produced with the generator is used to heat a working medium when the high temperature fuel cell block is being started up. For example, the working medium provided for the high temperature fuel cell block in normal operation may at the start be fed directly via a bypass to the gas motor, the energy of which is there-fore used for electrically heating the high temperature fuel cell block. The high temperature fuel cell block may 15 consequently be started up with the gas motor, which forms part of the overall high temperature fuel cell installation.
In particular, a working medium for the anode part and/or cathode part of the high temperature fuel cell block may be heated with the heat dissipated by the gas motor.
The latter object is achieved according to the invention by a high temperature fuel cell installation having at least one high temperature fuel cell block comprising an anode part and a cathode part. In order to increase the energy production, a gas motor coupled to a generator is provided, the gas motor being connected to the discharge path of the anode part of the high tempera-ture fuel cell block.
CA 022~3~64 1998-11-0 Preferably, at least one water precipitator is provided in the discharge path of the anode part. The water removed from the anode off-gas by at least one water precipitator may, for example, be fed via a feed water tank to a steam generator, the water subsequently evaporated being fed back to the working medium for the anode part of the high temperature fuel cell block. ~y virtue of this, even the water from the anode off-gas can be fed for reuse in the high temperature fuel cell block.
In particular, at least one heat e~ch~nger may be arranged in the discharge line of the gas motor.
In a further refinement, a steam generator i8 provided in the discharge line of the gas motor. Using the ~team generator, the water from the off-gas of the anode part of the high temperature fuel cell block is evaporated for reuse in the cathode part.
Preferably, the generator is connected to a heating device arranged in the feed path of the cathode part. A fraction of the electric current produced in the generator is used to heat the working medium for the cathode part.
In particular, the generator may be connected to an electrical network in order to feed it with electric current. The current may be fed to a load via the electrical network.
For further explanation of the invention, reference will be made to the illustrative embodiment in the drawing, the single , .
- CA 022~3~64 lgss-ll-o~
figure of which schematically represents a high tempera-ture fuel cell installation.
According to the figure, a high temperature fuel cell installation 2 comprises a high temperature fuel cell block 4 which is divided into an anode part 6 with anode gas spaces (not shown in detail) and a cathode part 8 with cathode gas spaces (not further shown). The high temperature fuel cell block 4 is preferably composed of a multitude of high temperature fuel cells (not further shown) of planar design.
An invertor 10, which converts the direct current produced by the high temperature fuel cell block 4 into alternating current for an electrical network 18, is connected to the high temperature fuel cell block 4.
The anode part 6 is assigned an anode path 12 for supplying it with a working medium, for example hydrogen (H2) or a mixture of combustion gas and reaction vapor, this anode path 12 comprising a feed path 14 and a discharge path 16. Before feeding into the anode part 6, the working medium is referred to as "working medium for the anode part 6", and after it has left the anode part 6, it is referred to as "anode off-gas of the anode part 6".
A gas splitter 20, a mixing chamber 22 and a heat eYchAnger 24 are successively arranged, in that order in the flow direction, in the feed path 14 of the anode part 6 of the high temperature fuel cell block 4. A gas motor 26 is connected to the discharge path 16 of the anode part 6 of the , .
- CA 022~3~64 1998-ll-0 high temperature fuel cell block 4. The term "gas motor"
is in this context intended to mean a device for converting the chemical energy contained in the working medium (anode off-gas) into mechanical energy. A
generator 50, which converts the mechanical energy produced in the gas motor 26 into alternating current, i8 coupled to the gas motor 26. The alternating current is delivered to an electrical network 54 via a line 52.
The off-gas from the gas motor 26 is discharged by a discharge line 17 from the high temperature fuel cell installation 2. A heat ~Yrhanger 36, a steam generator 38 and a further heat ~X~hAnger 40 are successively arranged, in that order in the flow direction, in the discharge line 17.
Two water precipitators 30, 32 and a mixing chamber 34 are successively arranged, in that order in the flow direction, in the discharge path 16 of the anode part 6.
The working medium for the anode part 6 is fed into the anode part 6 of the high temperature fuel cell block 4 via the feed path 14. This being the case, the working medium firstly flows through the ga~ splitter 20, in which a fraction of the working medium is diverted from the feed path 14 via a line 44 and fed directly into the mixing chamber 34 arranged upstream of the gas motor 26 in the discharge path 16 of the anode part 6.
Operation of the gas motor 26 is therefore guaranteed even if not enough working medium is present in the anode off-gas of the anode part 6 of the high temperature fuel cell block 4. In the heat eYc-h~nger 24, the working CA 022~3~64 1998-11-0 medium for the anode part 6 i~ heated by the anode off-gas.
After the electrochemical reaction has taken place in the high temperature fuel cell block 4, the anode off-gas is discharged from the high temperature fuel cell block 4 via the discharge path 16. In the water precipitators 30 and 32, a large portion of the process water produced during the reaction in the high tempera-ture fuel cell block 4 is removed together with a fraction of the heat content of the anode off-gas.
After the procens water has been removed from the anode off-gas, the cooled anode off-gas passes as working medium via the ~;Y; ng chamber 34 into the gas motor 26.
In the latter, the working medium, i.e. the anode off-gas, is burnt to produce mechanical energy.
In the steam generator 38, the process waterremoved by the water precipitators 30, 32 from the anode off-gas is evaporated. For this purpose, the process water from the water precipitators 30, 32 is fed to the steam generator 38 via a line 60, in which a feed water tank 62 and a pump 64 are arranged. The feed water tank 62 is in this case used as a reservoir for the process water. The latter is fed in the required quantity to the steam generator 38 by the pump 64.
The water vapor produced in the steam generator 38 is fed via a line 68 to the mixing chamber 22 which is arranged in the feed path 14 of the anode part 6. The water - CA 022~3~64 lgss-ll-o~
vapor is therefore mixed with the working medium for the anode part 6 in order to heat this medium.
The heat obtained in the water precipitator 30 and in the further heat eYchAnger 40 can be fed via a line 120 carrying a heat-exchange medium into a local hot water network 122 (not shown in detail).
The cathode part 8 of the high temperature fuel cell block 4 is assigned a cathode path 80 which comprise~ a feed path 82 and a discharge path 84. A
compressor 86, a gas splitter 88, a ~iY;ng chamber 90, a heat ~YchAnger 92 and an electrical heating device 94 are succes~ively arranged, in that order in the flow direction, in the feed path 82 of the cathode part 8.
The working medium for the cathode part 8 is fed to the cathode part 8 via the feed path 82. This being the case, the working medium, for example air or air enriched with oxygen (~2) ~ i8 fed into the gas splitter 88 via the compre~or 86.
In the gas splitter 88, at lea~t a fraction of the working medium for the cathode part 8 is diverted from the feed path 82 of the cathode part 8 and fed via a line 100 through the heat ~YchAnger 36. It i8 then fed back via the mixing chamber 90 to the feed path 82. Since the heat exchanger 36 is connected downstream of the gas motor 26 in the discharge line 17 for the off-gas from the gas motor 26, the working medium for the cathode part 8 diverted from the feed path 82 is heated by the off-gas from the gas motor 26. The waste heat of the off-gas CA 022~3~64 1998-ll-0 from the gas motor 26 i~ therefore advantageously used to heat the working medium for the cathode part 8.
The undiverted fraction of the working medium passes directly via the line 82 into the ;Y; ng chamber 90, where it is recombined with the diverted fraction.
The working medium for the cathode part 8 is then heated in the heat exchanger 92 and in the electrical heating device 94. In the heat exchanger 92, the working medium for the cathode part 8 is heated by the cathode off-gas, and in the electrical heating device 94 it is electrically heated for starting up the high temperature fuel cell block 4. In this case, the electrical heating device 94 is supplied with current from the generator 50 assigned to the gas motor 26. The electrical heating device 94 is in this case supplied with current via a line 102 from the line 52.
The cathode off-gas i8 firstly fed via the discharge path 84 of the cathode path 8 through the heat ~YrhAnger 92, where it heats the working medium for the cathode part 8. It i8 then fed to a local heat-using system 110 (not shown in detail).
On the one hand, therefore, the gas motor 26 is operated using the anode off-ga~ from the high temperature fuel cell block 4 and on the other hand the gas motor 26 is used for starting up the high temperature fuel cell block 4. The process water obtained during the electrochemical reaction in the high temperature fuel cell block 4 is fed in the form of water vapor to the .
- CA 022~3~64 lsss-ll-o~
working medium for the anode part 6 in order to heat it.
Further, the current produced by the gas motor 26 and the generator 50 is used to operate the electrical heating device 94 for heating the working medium for the cathode part 8 of the high temperature fuel cell block 4. In addition, the heat of the off-gas from the gas motor 26 preheats the working medium for the cathode part 8 of the high temperature fuel cell block 4.
It i8 therefore possible for the etart-up process of the high temperature fuel cell installation 2 to be carried out merely using components which are provided in the high temperature fuel cell installation 2.
Claims (9)
1. A process for operating a high temperature fuel cell installation (2) comprising at least one high temperature fuel cell block (4) with an anode part (6) and a cathode part (8), at least a portion of the anode off-gas from the high temperature fuel cell block (4) being fed as working medium to a gas motor (26) coupled to a generator (50) in order to increase the energy production, and water and heat energy are withdrawn from the anode off-gas before feeding into the gas motor (26).
2. The process as claimed in claim 1, characterized in that the anode part (6) is supplied with a working medium to which water in the form of water vapor is fed before the feeding.
3. The process as claimed in claim 1 or 2, characterized in that a portion of the electric current produced with the generator (50) is used to heat a working medium when the high temperature fuel cell block (4) is being started up.
4. The process as claimed in one of claims 1 to 3, characterized in that a working medium for the anode part (6) and/or cathode part (8) of the high temperature fuel cell block (4) is heated with the heat dissipated by the gas motor (26).
5. A high temperature fuel cell installation (2) having at least one high temperature fuel cell block (4) comprising an anode part (6) and a cathode part (8) as well as a gas motor (26) coupled to a generator (50) in order to produce energy, the gas motor (26) being connected to the discharge path (16) of the anode part (6) of the high temperature fuel cell block (4), and at least one water precipitator (30, 32) being arranged in the discharge path (16) of the anode part (6).
6. The high temperature fuel cell installation (2) as claimed in claim 5, which has at least one heat exchanger (36, 40) in the discharge line (17) of the gas motor (26).
7. The high temperature fuel cell installation (2) as claimed in claim 6, which has a steam generator (38) in the discharge line (17) of the gas motor (26).
8. The high temperature fuel cell installation (2) as claimed in claim 6 or 7, characterized in that an electrical heating device (94) arranged in the feed path (82) of the cathode part (8) is connected to the generator (50).
9. The high temperature fuel cell installation (2) as claimed in one of claims 5 to 8, characterized in that the generator (50) is connected to an electrical network (54) in order to feed it with electric current.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19618331.6 | 1996-05-07 | ||
| DE19618331 | 1996-05-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2253564A1 true CA2253564A1 (en) | 1997-11-13 |
Family
ID=7793608
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002253564A Abandoned CA2253564A1 (en) | 1996-05-07 | 1997-04-28 | High-temperature fuel cell plant and process for operating the same |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0898790B1 (en) |
| JP (1) | JP2000509549A (en) |
| AT (1) | ATE207247T1 (en) |
| AU (1) | AU706599B2 (en) |
| CA (1) | CA2253564A1 (en) |
| DE (1) | DE59704971D1 (en) |
| WO (1) | WO1997042673A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6655325B1 (en) * | 1999-02-01 | 2003-12-02 | Delphi Technologies, Inc. | Power generation system and method with exhaust side solid oxide fuel cell |
| DE19906099C1 (en) * | 1999-02-13 | 2000-03-23 | Mtu Friedrichshafen Gmbh | High-temperature fuel cell layout for operating turbines includes a fuel cell block fitted with a current inverter and a turbine generator attached to at least one fuel cell block |
| DE10031864C1 (en) * | 2000-06-30 | 2002-06-20 | Zsw | Method for regulating the heat and / or electricity demand-driven operation of fuel cell systems |
| DE10045899A1 (en) * | 2000-09-16 | 2002-04-25 | Forschungszentrum Juelich Gmbh | Device and method for generating electricity |
| DE10056536C2 (en) * | 2000-11-15 | 2002-10-10 | Mtu Friedrichshafen Gmbh | A fuel cell assembly |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0789494B2 (en) * | 1986-05-23 | 1995-09-27 | 株式会社日立製作所 | Combined power plant |
| NL8901348A (en) * | 1989-05-29 | 1990-12-17 | Turboconsult Bv | METHOD AND APPARATUS FOR GENERATING ELECTRICAL ENERGY |
| JPH06267574A (en) * | 1993-03-12 | 1994-09-22 | Ishikawajima Harima Heavy Ind Co Ltd | No-load operating method for fuel cell plant |
| US5413879A (en) * | 1994-02-08 | 1995-05-09 | Westinghouse Electric Corporation | Integrated gas turbine solid oxide fuel cell system |
-
1997
- 1997-04-28 DE DE59704971T patent/DE59704971D1/en not_active Expired - Fee Related
- 1997-04-28 AT AT97922887T patent/ATE207247T1/en not_active IP Right Cessation
- 1997-04-28 AU AU28872/97A patent/AU706599B2/en not_active Ceased
- 1997-04-28 JP JP9539423A patent/JP2000509549A/en active Pending
- 1997-04-28 CA CA002253564A patent/CA2253564A1/en not_active Abandoned
- 1997-04-28 WO PCT/DE1997/000868 patent/WO1997042673A1/en active IP Right Grant
- 1997-04-28 EP EP97922887A patent/EP0898790B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| ATE207247T1 (en) | 2001-11-15 |
| AU2887297A (en) | 1997-11-26 |
| EP0898790B1 (en) | 2001-10-17 |
| DE59704971D1 (en) | 2001-11-22 |
| JP2000509549A (en) | 2000-07-25 |
| WO1997042673A1 (en) | 1997-11-13 |
| EP0898790A1 (en) | 1999-03-03 |
| AU706599B2 (en) | 1999-06-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |