Fuel cell system containing water injector and method of operating the same

Patent metadata

Field	Value
Publication number	US-2020243885-A1
Application number	US-202016741833-A
Country	US
Kind code	A1
Filing date	Jan 14, 2020
Priority date	Jan 29, 2019
Publication date	Jul 30, 2020
Grant date	—

Abstract

A method of operating a fuel cell system includes providing an anode exhaust from a fuel cell stack to a water injector, supplying water to the water injector, and injecting the water from the water injector into the anode exhaust to vaporize the water and generate a humidified anode exhaust.

First claim

1 . A fuel cell system, comprising:
a fuel cell stack; an anode exhaust conduit configured to receive an anode exhaust from the stack; and a water injector configured to inject water into the anode exhaust in the anode exhaust conduit.

2 . The system of claim 1 , further comprising:
an anode recuperator located below the water injector and configured to receive the anode exhaust from the stack, to heat fuel provided to the stack using heat from the anode exhaust and to provide the anode exhaust to the anode exhaust conduit and the water injector; and an anode exhaust cooler disposed above the water injector and the anode recuperator and configured to heat air provided to the stack using the anode exhaust provided from the water injector and the anode recuperator.

3 . The system of claim 2 , further comprising a water conduit extending through anode cooler and configured to provide the water to the water injector.

4 . The system of claim 3 , wherein:
the fuel cell system does not include a steam generator; the water injector comprises an injector ring disposed between the anode exhaust cooler and the anode recuperator; the injector ring is fluidly connected to the water conduit; and the injector ring is configured to inject the water into the anode exhaust which flows in the anode exhaust conduit from the anode recuperator to the anode exhaust cooler.

5 . The system of claim 4 , wherein the injector ring comprises injection apertures in a surface thereof and configured to inject the water into the anode exhaust.

6 . The system of claim 5 , further comprising a fuel conduit surrounded by the anode cooler insulation and the anode exhaust conduit, wherein the fuel conduit extends through the middle of the injector ring and configured to provide the fuel to the stack through the anode recuperator.

7 . The system of claim 6 , wherein the water injector further comprises a shroud surrounding the injector ring.

8 . The system of claim 7 , wherein:
the water injector further comprises restraint tabs connected to the fuel conduit and to the shroud; and the restraint tabs are configured to support the injector ring, such that the injector ring is disposed in a substantially horizontal plane.

9 . The system of claim 8 , wherein:
the restraint tabs are configured to prevent water from accumulating at a single location on the outer surface of the injector ring; and lowermost points of the restraint tabs vertically overlap with the injector ring.

10 . The system of claim 7 , wherein the water injector further comprises a mesh or a porous material disposed below the injector ring and configured to reduce or prevent water from dripping onto the anode recuperator, and a baffle disposed below the injector ring, wherein the baffle comprises:
a baffle ring disposed around the fuel conduit and vertically overlapped with the injector ring; and baffle tabs extending from the baffle ring and configured to align the baffle ring, such that the baffle ring is vertically overlapped with injector ring.

11 . The system of claim 7 , further comprising:
an anode tail gas oxidizer; a splitter configured to direct a first portion of the anode exhaust provided from the anode recuperator into the anode exhaust conduit and the water injector, and to direct a second portion of the anode exhaust provided from the anode recuperator into the anode tail gas oxidizer, wherein the shroud is configured to direct the water away from the splitter; and an anode recycle blower configured to recycle the first portion of the anode exhaust into the fuel conduit.

12 . A method of operating a fuel cell system comprising:
providing at least a portion of an anode exhaust from a fuel cell stack to a water injector; supplying water to the water injector; and injecting the water from the water injector into the at least the portion of the anode exhaust to vaporize and/or aerosolize the water and generate a humidified anode exhaust.

13 . The method of claim 12 , wherein the supplying water to the water injector comprises supplying the water in a liquid state to the water injector after the stack reaches a temperature of about 300° C. or more.

14 . The method of claim 12 , further comprising:
providing the anode exhaust from the stack to an anode recuperator to heat a fuel inlet stream flowing to the stack; splitting the anode exhaust provided from the anode recuperator into a first portion of the anode exhaust and a second portion of the anode exhaust; providing the first portion of the anode exhaust into the water injector, wherein the water is vaporized in the first portion of the anode exhaust stream to form the humidified anode exhaust; and providing the second portion of the anode exhaust into an anode tail gas oxidizer.

15 . The method of claim 14 , further comprising:
providing the humidified anode exhaust into an anode cooler to heat air flowing to the stack; and providing the humidified anode exhaust from the anode cooler into the fuel inlet stream flowing to the stack.

16 . The method of claim 14 , wherein:
the water injector comprises an injector ring disposed between the anode exhaust cooler and the anode recuperator; the water flows through water conduit into the injector ring; and the water is injected from the injector ring through apertures in the injector ring into the first portion of the anode exhaust stream.

17 . The method of claim 16 , wherein:
the fuel inlet stream flows to the stack through a fuel conduit surrounded by anode cooler insulation and by the injector ring; the anode cooler surrounds the anode cooler insulation; and the water conduit extends through the anode cooler insulation.

18 . The method of claim 17 , wherein the water injector further comprises a shroud surrounding the injector ring which prevents or reduces water flow into the anode tail gas oxidizer.

19 . The method of claim 18 , wherein the water injector further comprises restraint tabs connected to the fuel conduit and to the shroud, and configured to support the injector ring in a substantially horizontal plane.

20 . The method of claim 18 , wherein:
the water injector further comprises a mesh or a porous material disposed below the injector ring; and the mesh or porous material reduces or prevents water from dripping onto the anode recuperator.

21 . The method of claim 12 , wherein the water does not pass through a steam generator.

Assignees

• Bloom Energy Corp

Inventors

• Weingaertner David
• Hartana Ivan
• Edmonston David
• Petrucha Michael
• Perry Martin

Classifications

• H01M8/0662 Primary

  Treatment of gaseous reactants or gaseous residues, e.g. cleaning · CPC title

• H01M8/04097

  with recycling of the reactants (H01M8/04119, H01M8/04104 take precedence) · CPC title

• H01M8/04059

  Evaporative processes for the cooling of a fuel cell · CPC title

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title

• H01M8/04074

  Heat exchange unit structures specially adapted for fuel cell · CPC title