Detecting and controlling a fuel-rich condition of a reactor in a fuel cell system

• US 20080152969A1
• Filed: 12/22/2006
• Published: 06/26/2008
• Est. Priority Date: 12/22/2006
• Status: Abandoned Application

• Current Assignee: Plug Power Inc.
• Original Assignee: Plug Power Inc.
• Inventors: Dhand, Parshant, Feitelberg, Alan S., Zhou, Zhi, Poonamallee, Vishnu L.
• Application Number:
  US11/645,154
• Publication Number:
  US 20080152969A1
• Time in Patent Office: Days
• US Class Current: 429/17
• CPC Class Codes: H01M 2008/1095 Fuel cells with polymeric electrolytes
• CPC Class Codes: H01M 8/04373 of auxiliary devices, e.g. reformers, compressors, burners
• CPC Class Codes: H01M 8/0444 Concentration; Density H01M8/04492 takes precedence
• CPC Class Codes: H01M 8/04753 of fuel cell reactants
• CPC Class Codes: H01M 8/04776 at auxiliary devices, e.g. reformer, compressor, burner
• CPC Class Codes: H01M 8/0662 Treatment of gaseous reactants or gaseous residues, e.g. cleaning
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A fuel cell system includes a fuel cell stack, and a reactor to oxidize excess fuel exhausted from the fuel cell stack. A sensor associated with the reactor provides an output indication, and a controller detects a fuel-rich condition of the reactor based on the output indication from the sensor.

Claims

1. A fuel cell system comprising:

a fuel cell stack;

a reactor to oxidize excess fuel exhausted from the fuel cell stack;

a sensor associated with the reactor to provide an output indication; and

a controller to detect a fuel-rich condition of the reactor based on the output indication from the sensor.

2. The fuel cell system of claim 1, wherein the controller is configured to take corrective action in response to detecting the fuel-rich condition.

3. The fuel cell system of claim 1, wherein the sensor comprises an oxidant sensor to detect oxidant content in exhaust gas from the reactor.

4. The fuel cell system of claim 3, wherein the controller detects the fuel-rich condition in response to oxidant content in the exhaust gas less than a predefined threshold.

5. The fuel cell system of claim 1, wherein in response to detecting the fuel-rich condition, the controller is configured to further:

increase oxidant flow to the reactor.

6. The fuel cell system of claim 5, further comprising an oxidant blower, wherein the oxidant flow is increased by increasing a setting of the oxidant blower.

7. The fuel cell system of claim 5, wherein in response to detecting the fuel-rich condition, the controller is configured to further:

disable feedback control for the reactor, wherein the feedback control adjusts oxidant flow in response to a temperature of the reactor.

8. The fuel cell system of claim 7, wherein the controller is configured to further:

determine whether the reactor has returned to a fuel-lean condition; and

in response to determining that the reactor has returned to the fuel-lean condition, enable the feedback control for the reactor.

9. The fuel cell system of claim 1, wherein the reactor comprises an anode tailgas oxidizer.

10. The fuel cell system of claim 9, further comprising an oxidant blower and a three-way valve connected to receive oxidant flow from the output of the oxidant blower, and to divide oxidant flow between a cathode input of the fuel cell stack and the anode tailgas oxidizer.

11. The fuel cell system of claim 10, wherein the controller is configured to adjust a setting of the oxidant blower in response to detecting the fuel-rich condition.

12. The fuel cell system of claim 1, wherein the reactor comprises a catalyst, and wherein the sensor comprises a temperature sensor provided at the catalyst.

13. The fuel cell system of claim 12, further comprising an oxidant blower, wherein the controller is configured to perform a test that changes a setting of the oxidant blower to determine whether the reactor is in the fuel-rich condition.

14. The fuel cell system of claim 13, wherein the controller is configured to increase the setting of the oxidant blower to determine whether the temperature sensor indicates that the temperature of the reactor increases or decreases, wherein the fuel-rich condition is indicated if the temperature of the reactor increases with increase in the speed of the oxidant blower.

15. The fuel cell system of claim 1, wherein the controller is configured to further:

detect whether the reactor has entered the fuel-rich condition too frequently; and

in response to detecting that the reactor has entered the fuel-rich condition too frequently, increase a fuel stoichiometry of the fuel cell system.

16. The fuel cell system of claim 1, wherein the controller is configured to further:

detect whether the reactor has entered the fuel-rich condition too frequently; and

in response to detecting that the reactor has entered the fuel-rich condition too frequently, increase an oxidant stoichiometry of the fuel cell system.

17. A method for use in a fuel cell system, comprising:

oxidizing, with a reactor, excess fuel exhausted from a fuel cell stack;

receiving an output indication from a sensor associated with the reactor;

detecting whether the reactor has entered a fuel-rich condition in response to the output indication; and

performing a corrective action in response to detecting that the reactor has entered a fuel-rich condition.

18. The method of claim 17, wherein taking the corrective action comprises increasing oxidant flow to the reactor.

19. The method of claim 18, wherein taking the corrective action further comprises disabling feedback control based on temperature of the reactor.

20. The method of claim 17, wherein detecting that the reactor has entered the fuel-rich condition is in response to detecting that oxidant content of exhaust gas from the reactor is less than a predefined threshold.

21. The method of claim 17, wherein receiving the output indication from the sensor comprises receiving the output indication from an oxidant sensor.

22. The method of claim 17, wherein receiving the output indication from the sensor comprises receiving a temperature indication from a temperature sensor.

23. The method of claim 17, wherein taking the corrective action comprises adjusting a setting of an oxidant blower in the fuel cell system.

24. An article comprising at least one storage medium that contains instructions for use in a fuel cell system, the instructions when executed causing a controller to:

receive an output indication from a sensor associated with a reactor, wherein the reactor oxidizes excess fuel exhausted from a fuel cell in the fuel cell system;

detect whether the reactor has entered a fuel-rich condition in response to the output indication; and

perform a corrective action in response to detecting that the reactor has entered a fuel-rich condition.