Pressurized fuel cell power plant with air bypass

• US 3,976,506 A
• Filed: 02/12/1975
• Issued: 08/24/1976
• Est. Priority Date: 02/12/1975
• Status: Expired due to Term

• Current Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Landau, Michael B.
• Primary Examiner(s): Mack, John H.
• Assistant Examiner(s): Feeley, H. A.
• Application Number:
  US05/549,598
• Time in Patent Office: 559 Days
• Field of Search: 136/86 A, 136/86 R, 136/86 B, 136/86 C
• US Class Current: 429/414
• CPC Class Codes: F02C 6/00 Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas-turbine plants for special use
• CPC Class Codes: F02C 6/10 supplying working fluid to a user, e.g. a chemical process, which returns working fluid to a turbine of the plant
• CPC Class Codes: H01M 8/04007 related to heat exchange
• CPC Class Codes: H01M 8/04014 Heat exchange using gaseous fluids; Heat exchange by combustion of reactants
• CPC Class Codes: H01M 8/04029 Heat exchange using liquids
• CPC Class Codes: H01M 8/04089 of gaseous reactants
• CPC Class Codes: H01M 8/04156 with product water removal
• CPC Class Codes: H01M 8/06 Combination of fuel cells with means for production of reactants or for treatment of residues regenerative fuel cells H01M8/18
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A power plant for producing electricity uses fuel cells run on pressurized air and pressurized fuel. The air is compressed by compressor apparatus which is driven by waste energy in the form of hot pressurized gases produced in the power plant. In one embodiment the compressor apparatus includes a turbine operably connected to a compressor for driving the same. At part power, in order to maintain the pressure of the air being fed to the cells while reducing the amount of air fed to the cells, a portion of the compressed air is bypassed around the fuel cells, is increased in temperature using an auxiliary burner, and is delivered into the turbine to help drive the compressor. By doing this the mass flow of air through the cells may be reduced without reducing the mass flow of gases into the turbine thereby maintaining the speed of the compressor at part power.

Claims

1. A power plant for generating electricity comprising:

a fuel cell stack including a plurality of fuel cells connected electrically in series through a load, each cell comprising a cathode electrode, an anode electrode, an electrolyte disposed therebetween, a cathode gas space on the nonelectrolyte side of said cathode electrode and an anode gas space on the nonelectrolyte side of said anode electrode;

compressor means including a compressor operably connected to turbine means for compressing air to greater than 2 atmospheres pressure;

means for delivering air at a pressure of at least 2 atmospheres from said compressor into said cathode gas space;

fuel conditioning apparatus including reactor means for producing hydrogen from a hydrogen containing fuel;

burner means for providing heat to said reactor means;

means for delivering pressurized hydrogen containing fuel into said reactor means;

means for delivering pressurized hydrogen from said fuel conditioning apparatus into said anode gas space;

means for delivering anode effluent gases into said burner means for providing fuel to said burner means;

means for bypassing, at part power, a portion of the compressed air from said compressor around said cathode gas space;

means for delivering effluent gases from said cathode gas space, effluent gases from said burner means, and said bypassed compressed air into said turbine means for powering said turbine means and driving said compressor; and

auxiliary burner means in heat exchange relationship with said gases being delivered into said turbine means, for adding additional heat to the gases being delivered into said turbine means.

2. The power plant according to claim 1 wherein said means for bypassing compressed air around said cathode gas space includes a bypass leg, and said auxiliary burner means is disposed in said bypass leg for burning said bypassed air therein.

3. The power plant according to claim 1 wherein said electrolyte is an acid electrolyte.

4. The power plant according to claim 1 wherein said electrolyte is phosphoric acid.

5. The power plant according to claim 1 wherein said reactor means is a steam reforming reactor and said burner means is a reactor burner.

6. The power plant according to claim 5 wherein said means for delivering air from said compressor into said cathode gas space includes means for delivering air from said compressor into said burner means.

7. The power plant according to claim 1 wherein said compressor and said turbine means is of fixed geometry.

8. The power plant according to claim 1 wherein said means for bypassing around said cathode gas space includes means for bypassing around said burner means.

9. The power plant according to claim 8 wherein said auxiliary burner means is disposed in said power plant such that the bypassed compressed air flows therethrough and is burned therein.

10. A power plant for generating electricity comprising:

a fuel cell stack including a plurality of fuel cells connected electrically in series through a load, each cell comprising a cathode electrode, an anode electrode, and acid electrolyte disposed therebetween, a cathode gas space on the nonelectrolyte side of said cathode electrode and an anode gas space on the nonelectrolyte side of said anode electrode;

fuel conditioning apparatus including a steam reforming reactor for producing hydrogen and a reactor burner for providing heat to said reactor;

condenser means;

boiler means;

turbocharger means including a compressor for compressing air to greater than 2 atmospheres pressure and a turbine operably connected to said compressor for driving said compressor;

auxiliary burner means;

fuel supply means including a hydrogen containing fuel;

means for delivering compressed air at greater than 2 atmospheres pressure from said turbocharger means into said cathode gas space;

means for delivering the effluent from said cathode gas space into said condenser means for condensing out the water therein;

means for delivering the condensed out water from said condenser means to said boiler means for converting said water to steam;

means for delivering pressurized steam from said boiler means and pressurized hydrogen containing fuel from said fuel supply means into said steam reforming reactor;

means for delivering pressurized hydrogen from said fuel conditioning apparatus into said anode gas space;

means for delivering anode effluent gases into said reactor burner;

means for delivering compressed air from said turbocharger means into said reactor burner;

means for bypassing, at part power, a portion of the compressed air from said turbocharger means around said cathode gas space and around said fuel conditioning apparatus including means for combining said bypassed compressed air with the effluent gases from said reactor burner and the effluent gases from said cathode gas space;

means for delivering the combined gases into said turbine; and

means for delivering fuel into said auxiliary burner means, said auxiliary burner means being disposed in said power plant such that the bypassed compressed air flows therethrough and is burned therein for adding heat to the gases entering said turbine.

11. The power plant according to claim 10 wherein said means for bypassing a portion of the compressed air includes a bypass leg and said auxiliary burner means is disposed in said bypass leg.

12. The power plant according to claim 10 wherein said compressor and said turbine is of fixed geometry.

13. The power plant according to claim 10 wherein said boiler means is disposed in heat exchange relationship with said fuel cell stack wherein heat from said stack is used to convert the water in said boiler to steam.

14. In the process for generating electricity in a power plant comprising fuel conditioning apparatus including reactor means, a compressor operably connected to turbine means, and a fuel cell stack including a plurality of fuel cells connected electrically in series through a load, each cell comprising a cathode electrode, an anode electrode, an electrolyte disposed therebetween, a cathode gas space on the nonelectrolyte side of said cathode electrode and an anode gas space on the nonelectrolyte side of said anode electrode, the steps of:

compressing air to greater than 2 atmospheres in said compressor;

delivering compressed air at greater than 2 atmospheres pressure from said compressor into said cathode gas space;

delivering pressurized hydrogen containing fuel into said reactor means;

producing hydrogen in said reactor means;

providing heat for said step of producing hydrogen by burning anode effluent gases in a burner;

delivering pressurized hydrogen from said fuel conditioning apparatus into said anode gas space;

bypassing, at part power, a portion of the compressed air from said compressor around said cathode gas space and around said fuel conditioning apparatus;

burning said bypassed air in an auxiliary burner; and

delivering effluent gases from said cathode gas space, said burner, and said auxiliary burner into said turbine means for driving said compressor.

15. The process according to claim 14 wherein said step of producing hydrogen includes steam reforming said hydrogen containing fuel.

16. The process according to claim 14 including the step of delivering said cathode effluent gases and said burner effluent gases into said auxiliary burner along with said bypassed air before delivering them into said turbine.

17. The process according to claim 15 including the steps of:

condensing water out of the effluent gases from said cathode gas space;

converting said water to pressurized steam; and

delivering said steam into said steam reforming reactor.