Hybrid fuel heat exchanger—pre-reformer in SOFC systems

• US 8,920,997 B2
• Filed: 09/27/2007
• Issued: 12/30/2014
• Est. Priority Date: 07/26/2007
• Status: Active Grant

• Current Assignee: Bloom Energy Corporation
• Original Assignee: Bloom Energy Corporation
• Inventors: Venkataraman, Swaminathan
• Primary Examiner(s): Gilliam, Barbara
• Assistant Examiner(s): ESSEX, STEPHAN J
• Application Number:
  US11/905,051
• Publication Number:
  US 20090029204A1
• Time in Patent Office: 2,651 Days
• US Class Current: 429/434
• CPC Class Codes: H01M 8/04014 Heat exchange using gaseous fluids; Heat exchange by combustion of reactants
• CPC Class Codes: H01M 8/0612 from carbon-containing material
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A fuel cell system includes at least one fuel cell stack, a fuel inlet conduit, and a fuel heat exchanger containing a fuel reformation catalyst. The fuel heat exchanger is connected to the fuel inlet conduit and to at least one fuel cell system exhaust conduit which in operation provides a high temperature exhaust stream to the fuel heat exchanger.

Claims

1. A fuel cell system, comprising:

at least one fuel cell stack;

a fuel inlet conduit;

a fuel exhaust conduit;

a fuel exhaust recycling conduit;

an anode tail gas oxidizer (ATO);

a splitter; and

a fuel heat exchanger containing a fuel reformation catalyst, wherein;

the fuel heat exchanger is connected to the fuel inlet conduit and to the fuel exhaust conduit which in operation provides a high temperature exhaust stream from the fuel cell stack to the fuel heat exchanger;

the fuel heat exchanger is fluidly connected to the splitter which is connected to the fuel exhaust recycling conduit which in operation recycles a first portion of the high temperature exhaust stream from the fuel heat exchanger via the splitter to the fuel inlet conduit;

the splitter is fluidly connected to the ATO and provides a second portion of the high temperature exhaust stream to the ATO; and

the first portion of the high temperature exhaust stream and the second portion of the high temperature exhaust stream have a same relative hydrogen content upon immediate output from the splitter.

2. The system of claim 1, wherein the at least one fuel cell stack comprises at least one SOFC stack.

3. The system of claim 1, wherein the fuel heat exchanger comprises a multi-stream heat exchanger which contains passages for at least three flow streams.

6. The system of claim 1, wherein the fuel heat exchanger comprises fins coated with the fuel reformation catalyst.

7. The system of claim 6, wherein the fuel reformation catalyst comprises at least one of nickel or rhodium.

8. The system of claim 7, wherein rhodium is located in a leading segment and nickel is located in a trailing segment of the fuel heat exchanger.

9. The system of claim 1, further comprising a hydrocarbon fuel source connected to the fuel inlet conduit.

4. A fuel cell system, comprising:

at least one fuel cell stack;

a fuel inlet conduit;

an anode tail gas oxidizer (ATO); and

a multi-stream heat exchanger containing a fuel reformation catalyst and passages for at least three flow streams,

wherein;

the multi-stream heat exchanger is connected to the fuel inlet conduit and to at least one fuel cell system exhaust conduit which in operation provides a high temperature exhaust stream to the multi-stream heat exchanger,

the fuel inlet conduit is connected to a first inlet of the multi-stream heat exchanger;

an air inlet conduit is connected to a second inlet of the multi-stream heat exchanger;

a fuel cell stack anode exhaust conduit is connected to a third inlet of the multi-stream heat exchanger;

an ATO exhaust conduit is connected to fourth inlet of the multi-stream heat exchanger;

a fuel cell stack fuel inlet is connected to a first outlet of the multi-stream heat exchanger; and

a fuel cell stack air inlet is connected to a second outlet of the multi-stream heat exchanger.

5. The system of claim 4, wherein the at least one fuel cell stack, the ATO and the multi-stream heat exchanger are located inside a hotbox.