US20080311454A1 - Turbocompressor impelling fuel recycle in fuel cell power plant - Google Patents
Turbocompressor impelling fuel recycle in fuel cell power plant Download PDFInfo
- Publication number
- US20080311454A1 US20080311454A1 US10/804,342 US80434204A US2008311454A1 US 20080311454 A1 US20080311454 A1 US 20080311454A1 US 80434204 A US80434204 A US 80434204A US 2008311454 A1 US2008311454 A1 US 2008311454A1
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- US
- United States
- Prior art keywords
- fuel
- gas
- flow fields
- power plant
- hydrogen
- 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.)
- Granted
Links
- 239000000446 fuel Substances 0.000 title claims abstract description 90
- 239000001257 hydrogen Substances 0.000 claims abstract description 22
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 22
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000002737 fuel gas Substances 0.000 claims abstract 9
- 239000007800 oxidant agent Substances 0.000 claims description 23
- 230000001590 oxidative effect Effects 0.000 claims description 23
- 239000000376 reactant Substances 0.000 claims description 16
- 239000007789 gas Substances 0.000 claims description 14
- 239000012528 membrane Substances 0.000 claims description 10
- 238000005086 pumping Methods 0.000 claims 3
- 150000002431 hydrogen Chemical class 0.000 abstract description 8
- 239000003570 air Substances 0.000 description 9
- 230000003071 parasitic effect Effects 0.000 description 5
- 238000004064 recycling Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000007792 addition Methods 0.000 description 1
- 239000012080 ambient air Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 235000003642 hunger Nutrition 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 239000002915 spent fuel radioactive waste Substances 0.000 description 1
- 230000037351 starvation Effects 0.000 description 1
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
- H01M8/04082—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
- H01M8/04111—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants using a compressor turbine assembly
-
- 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
-
- 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
Definitions
- This invention relates to the use of turbocompressors to impel fuel recycle gas from fuel flow exits to fuel flow inlets, the turbine being propelled either by (a) high pressure hydrogen fuel or (b) oxidant flow field exhaust.
- Recycling the fuel requires a recycle blower or compressor which must be powered by electricity generated by the fuel cell, which is referred to as parasitic power. Further, pure hydrogen is difficult to pump due to its low density, and the pump motor must be appropriately rated to be non-sparking for safety.
- Objects of the invention include: elimination of safety concerns attendant traditional fuel recycle blowers; reducing or eliminating parasitic power requirements for impelling fuel recycle gas; a simpler, more reliable fuel recycle impeller; omitting a powered motor in a recycle impeller; and improved implementation of fuel cell stack fuel recycle.
- recycle fuel in a fuel cell power plant is impelled by a compressor portion of a turbocompressor, the turbine of which is driven either by (a) high pressure hydrogen fuel or (b) exhaust from the oxidant flow field exit.
- high pressure hydrogen from a tank system drives the turbine, thereby totally eliminating any parasitic load on the fuel cell power plant.
- air exhaust is used to operate a fuel recycle turbocompressor.
- Fuel cell stacks employing water transport plates operating near atmospheric pressure have a sufficiently low pressure drop across the oxidant gas flow fields that the air exhaust has sufficient pressure to operate the fuel recycle turbocompressor.
- the invention may be used in fuel cell stacks which employ pressurized oxidant gas and having an air exhaust that is higher than ambient pressure.
- Use of the invention may completely eliminate the need for a conventional fuel recycle compressor with a drive motor, which is advantageous with respect to system simplicity and system safety.
- FIG. 1 is a simplified, stylized, schematic illustration of a fuel cell stack according to the invention having recycle fuel impelled by a turbocompressor which is driven by high pressure hydrogen from a tank system.
- FIG. 2 is a simplified, stylized, schematic illustration of a fuel cell stack according to the invention having recycle fuel impelled by a turbocompressor which is driven by the oxidant exhaust of the fuel cell stack.
- a fuel cell power plant 7 includes a fuel cell stack 8 having a plurality of fuel cells, each with an anode 9 and a cathode 10 .
- the anode is fed hydrogen-rich fuel, such as from a source of pressurized hydrogen 14 .
- the hydrogen 14 is provided by a conduit 16 to a compressor 17 of a turbocompressor 18 , which drives a shaft 19 which in turn drives a compressor 20 .
- the flow from the turbine 17 over a conduit 22 passes through a process-controlling valve 23 which is responsive to a signal on a line 24 from a controller 25 .
- the correct amount of fuel is thus provided by the valve 23 over a conduit 28 to the fuel flow fields within the anode 9 of each cell.
- the partially spent fuel exiting from the anode flow fields into a conduit 30 may be expelled to ambient (or a burner, as is known) through a valve 31 in response to a signal on a line 32 from the controller 25 , so as to purge the anode flow fields in a conventional way, when necessary.
- the partially depleted fuel in the conduit 30 is also provided by a conduit 34 to the inlet of the compressor 20 , the outlet of which on a conduit 35 is connected to the inlet conduit 28 , thus providing the fuel recycle function.
- each fuel cell includes oxidant reactant gas flow fields which in this embodiment receive air over a conduit 38 from a pump 39 that is controlled by a signal 40 from the controller 25 .
- the flow of air is also controlled by a pressure-creating restriction, which may be a valve 42 controlled by a signal on a line 43 from the controller 25 , as is conventional.
- the stochiometry of oxidant flow can be controlled by the valve 42 to suit the operational level (power output), which the controller 25 determines by adjusting the amount of inlet fuel through the valve 23 .
- the embodiment of FIG. 1 operates passively in that the more inlet fuel there is, the more bypass fuel there will be, and the two are tied together by the turbocompressor 18 .
- a second embodiment is a fuel cell power plant 7 a of the invention illustrated in FIG. 2 , fueled from a source 14 a , may not only be used with a high pressure source of hydrogen, but it also may be used with hydrogen-rich reformate gas generated by a reformer, as is known.
- the turbine 17 a of the turbocompressor 18 a is driven by the exhaust in the conduit 41 from the cathode oxidant flow fields.
- the recycle rate will be dependent upon the flow of air through the cathode sides of the cells. As the current density varies, the recycle rate, and therefore the recycle pressure will also vary. So long as the components are selected and balanced to provide for a minimally sufficient fuel recycle flow, the embodiment of FIG. 2 achieves the advantages of eliminating the electric motor without unduly affecting parasitic power, even if there is no high pressure hydrogen source.
- turbocompressors of the present invention may be utilized to impel recycle fuel to other than the first stage of fuel flow fields as is described in copending U.S. patent application Ser. No. 10/765,735 filed Jan. 27, 2004 and entitled “Fuel Cell System Having Inlet Fuel to More Than One and/or Recycle to Less Than All of the Fuel Fields”.
Abstract
Description
- This invention relates to the use of turbocompressors to impel fuel recycle gas from fuel flow exits to fuel flow inlets, the turbine being propelled either by (a) high pressure hydrogen fuel or (b) oxidant flow field exhaust.
- In order to achieve very high fuel utilization (such as around 99%) in a fuel cell power plant, it is necessary to reduce the amount of hydrogen exiting the fuel cell. However, attempts to reach perfect utilization result in fuel starvation, typically in a spotty fashion, at various locations within individual cells, and in various cells. Recycling fuel, from the fuel flow field exits back to the fuel flow field inlets, allows the overall fuel cell stack utilization to be greater than the utilization in the fuel cells. Recycling also tends to cause a more even distribution of the fuel, and mitigates the effects of inert gases, such as nitrogen which migrates from the anode through the porous membrane.
- Recycling the fuel requires a recycle blower or compressor which must be powered by electricity generated by the fuel cell, which is referred to as parasitic power. Further, pure hydrogen is difficult to pump due to its low density, and the pump motor must be appropriately rated to be non-sparking for safety.
- Objects of the invention include: elimination of safety concerns attendant traditional fuel recycle blowers; reducing or eliminating parasitic power requirements for impelling fuel recycle gas; a simpler, more reliable fuel recycle impeller; omitting a powered motor in a recycle impeller; and improved implementation of fuel cell stack fuel recycle.
- According to the present invention, recycle fuel in a fuel cell power plant is impelled by a compressor portion of a turbocompressor, the turbine of which is driven either by (a) high pressure hydrogen fuel or (b) exhaust from the oxidant flow field exit.
- In one embodiment, high pressure hydrogen from a tank system drives the turbine, thereby totally eliminating any parasitic load on the fuel cell power plant. In other embodiments, air exhaust is used to operate a fuel recycle turbocompressor. Fuel cell stacks employing water transport plates operating near atmospheric pressure have a sufficiently low pressure drop across the oxidant gas flow fields that the air exhaust has sufficient pressure to operate the fuel recycle turbocompressor. The invention, however, may be used in fuel cell stacks which employ pressurized oxidant gas and having an air exhaust that is higher than ambient pressure. Not only is this advantageous for driving a recycle turbocompressor, but it is also advantageous from a water-balance perspective since pressurized air at any given temperature, carries less water vapor than ambient air; therefore, less water is lost from the fuel cell stacks when pressurized air is used. The invention can also be used with fuel cells operated at higher temperature. The invention is particularly well suited for use where oxidant gas stochiometry is well in excess of 100%. Thus, even if use of the oxidant gas exhaust to drive the bypass fuel impeller increases air blower parasitic power, it will only increase very slightly.
- Use of the invention may completely eliminate the need for a conventional fuel recycle compressor with a drive motor, which is advantageous with respect to system simplicity and system safety.
- Other objects, features and advantages of the present invention will become more apparent in the light of the following detailed description of exemplary embodiments thereof, as illustrated in the accompanying drawing.
-
FIG. 1 is a simplified, stylized, schematic illustration of a fuel cell stack according to the invention having recycle fuel impelled by a turbocompressor which is driven by high pressure hydrogen from a tank system. -
FIG. 2 is a simplified, stylized, schematic illustration of a fuel cell stack according to the invention having recycle fuel impelled by a turbocompressor which is driven by the oxidant exhaust of the fuel cell stack. - Referring to
FIG. 1 , a fuelcell power plant 7 according to the present invention includes afuel cell stack 8 having a plurality of fuel cells, each with ananode 9 and acathode 10. As is known, the anode is fed hydrogen-rich fuel, such as from a source of pressurizedhydrogen 14. - According to the invention, the
hydrogen 14 is provided by aconduit 16 to acompressor 17 of aturbocompressor 18, which drives ashaft 19 which in turn drives acompressor 20. The flow from theturbine 17 over aconduit 22 passes through a process-controllingvalve 23 which is responsive to a signal on aline 24 from acontroller 25. The correct amount of fuel is thus provided by thevalve 23 over aconduit 28 to the fuel flow fields within theanode 9 of each cell. The partially spent fuel exiting from the anode flow fields into aconduit 30 may be expelled to ambient (or a burner, as is known) through avalve 31 in response to a signal on aline 32 from thecontroller 25, so as to purge the anode flow fields in a conventional way, when necessary. The partially depleted fuel in theconduit 30 is also provided by aconduit 34 to the inlet of thecompressor 20, the outlet of which on aconduit 35 is connected to theinlet conduit 28, thus providing the fuel recycle function. - As is known, the cathode side of each fuel cell includes oxidant reactant gas flow fields which in this embodiment receive air over a
conduit 38 from apump 39 that is controlled by asignal 40 from thecontroller 25. The flow of air is also controlled by a pressure-creating restriction, which may be avalve 42 controlled by a signal on aline 43 from thecontroller 25, as is conventional. - The stochiometry of oxidant flow can be controlled by the
valve 42 to suit the operational level (power output), which thecontroller 25 determines by adjusting the amount of inlet fuel through thevalve 23. The embodiment ofFIG. 1 operates passively in that the more inlet fuel there is, the more bypass fuel there will be, and the two are tied together by theturbocompressor 18. - A second embodiment is a fuel cell power plant 7 a of the invention illustrated in
FIG. 2 , fueled from a source 14 a, may not only be used with a high pressure source of hydrogen, but it also may be used with hydrogen-rich reformate gas generated by a reformer, as is known. In the embodiment ofFIG. 2 , theturbine 17 a of theturbocompressor 18 a is driven by the exhaust in theconduit 41 from the cathode oxidant flow fields. In this case, the recycle rate will be dependent upon the flow of air through the cathode sides of the cells. As the current density varies, the recycle rate, and therefore the recycle pressure will also vary. So long as the components are selected and balanced to provide for a minimally sufficient fuel recycle flow, the embodiment ofFIG. 2 achieves the advantages of eliminating the electric motor without unduly affecting parasitic power, even if there is no high pressure hydrogen source. - The turbocompressors of the present invention may be utilized to impel recycle fuel to other than the first stage of fuel flow fields as is described in copending U.S. patent application Ser. No. 10/765,735 filed Jan. 27, 2004 and entitled “Fuel Cell System Having Inlet Fuel to More Than One and/or Recycle to Less Than All of the Fuel Fields”.
- The aforementioned patent applications is incorporated herein by reference.
- Thus, although the invention has been shown and described with respect to exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made therein and thereto, without departing from the spirit and scope of the invention.
Claims (9)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US10/804,342 US7465510B1 (en) | 2004-03-19 | 2004-03-19 | Turbocompressor impelling fuel recycle in fuel cell power plant |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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US10/804,342 US7465510B1 (en) | 2004-03-19 | 2004-03-19 | Turbocompressor impelling fuel recycle in fuel cell power plant |
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Publication Number | Publication Date |
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US7465510B1 US7465510B1 (en) | 2008-12-16 |
US20080311454A1 true US20080311454A1 (en) | 2008-12-18 |
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US10/804,342 Active 2025-11-15 US7465510B1 (en) | 2004-03-19 | 2004-03-19 | Turbocompressor impelling fuel recycle in fuel cell power plant |
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080311441A1 (en) * | 2007-06-14 | 2008-12-18 | Hochgraf Clark G | Fuel cell system using cathode exhaust for anode recirculation |
US20100203365A1 (en) * | 2007-08-07 | 2010-08-12 | Daimler Ag | Method and device for operating a fuel cell system having a recirculation blower disposed in a fuel circuit of the fuel cell system |
DE102011007615A1 (en) * | 2011-04-18 | 2012-10-18 | Robert Bosch Gmbh | Fuel cell system has exhaust air duct provided with gas flow regulating element that is connected to control unit |
WO2023006353A1 (en) * | 2021-07-30 | 2023-02-02 | Robert Bosch Gmbh | Fuel cell system and recirculation device for recirculating anode exhaust gas in a fuel cell system |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102010035860A1 (en) * | 2010-08-30 | 2012-03-01 | Daimler Ag | The fuel cell system |
CN112310437A (en) * | 2019-07-15 | 2021-02-02 | 国家能源投资集团有限责任公司 | Solid oxide fuel cell system and method for generating electricity by using solid oxide fuel cell |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20030143448A1 (en) * | 2000-10-30 | 2003-07-31 | Questair Technologies Inc. | High temperature fuel cell power plant |
US6607854B1 (en) * | 2000-11-13 | 2003-08-19 | Honeywell International Inc. | Three-wheel air turbocompressor for PEM fuel cell systems |
US20050164069A1 (en) * | 2004-01-27 | 2005-07-28 | Margiott Paul R. | Fuel cell system having inlet fuel to more than one and/or recycle to less than all of the fuel fields |
-
2004
- 2004-03-19 US US10/804,342 patent/US7465510B1/en active Active
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20030143448A1 (en) * | 2000-10-30 | 2003-07-31 | Questair Technologies Inc. | High temperature fuel cell power plant |
US6607854B1 (en) * | 2000-11-13 | 2003-08-19 | Honeywell International Inc. | Three-wheel air turbocompressor for PEM fuel cell systems |
US20050164069A1 (en) * | 2004-01-27 | 2005-07-28 | Margiott Paul R. | Fuel cell system having inlet fuel to more than one and/or recycle to less than all of the fuel fields |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080311441A1 (en) * | 2007-06-14 | 2008-12-18 | Hochgraf Clark G | Fuel cell system using cathode exhaust for anode recirculation |
US20100203365A1 (en) * | 2007-08-07 | 2010-08-12 | Daimler Ag | Method and device for operating a fuel cell system having a recirculation blower disposed in a fuel circuit of the fuel cell system |
US8765319B2 (en) * | 2007-08-07 | 2014-07-01 | Daimler Ag | Method and device for operating a fuel cell system having a recirculation blower disposed in a fuel circuit of the fuel cell system |
DE102011007615A1 (en) * | 2011-04-18 | 2012-10-18 | Robert Bosch Gmbh | Fuel cell system has exhaust air duct provided with gas flow regulating element that is connected to control unit |
WO2023006353A1 (en) * | 2021-07-30 | 2023-02-02 | Robert Bosch Gmbh | Fuel cell system and recirculation device for recirculating anode exhaust gas in a fuel cell system |
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US7465510B1 (en) | 2008-12-16 |
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