Ultra high efficiency fuel cell power generation system

Patent metadata

Field	Value
Publication number	US-2020251755-A1
Application number	US-201916266699-A
Country	US
Kind code	A1
Filing date	Feb 4, 2019
Priority date	Feb 4, 2019
Publication date	Aug 6, 2020
Grant date	—

Abstract

A fuel cell system includes a fuel cell having a cathode and an anode configured to receive a portion of a hydrocarbon feed and to output an anode exhaust stream comprising carbon dioxide, hydrogen, and water; and an electrolyzer cell having a cathode and an anode. The anode of the electrolyzer cell is configured to receive a first portion of the anode exhaust stream and another portion of the hydrocarbon feed, and to generate a hydrogen stream.

First claim

What is claimed is:

1 . A fuel cell system comprising:
a fuel cell having a cathode and an anode configured to receive a portion of a hydrocarbon feed and to output an anode exhaust stream comprising carbon dioxide, hydrogen, and water; and an electrolyzer cell having a cathode and an anode, wherein the anode of the electrolyzer cell is configured to receive a first portion of the anode exhaust stream and another portion of the hydrocarbon feed, and to generate a hydrogen stream.

2 . The fuel cell system according to claim 1 , wherein the anode of the electrolyzer cell is further configured to remove carbon dioxide from the first portion of the anode exhaust stream.

3 . The fuel cell system according to claim 1 , further comprising:
an anode gas oxidizer configured to oxidize a gas stream to remove carbon dioxide and nitrogen therefrom and to output an oxidized exhaust; a heat exchanger configured to receive an air stream and the oxidized exhaust, and to transfer heat from the oxidized exhaust to the air stream; and a cathode supply line configured to supply a heated air stream output from the heat exchanger to the cathode of the fuel cell.

4 . The fuel cell system according to claim 3 , wherein the gas stream oxidized by the anode gas oxidizer comprises a second portion of the anode exhaust stream.

5 . The fuel cell system according to claim 3 , wherein the air stream received by the heat exchanger comprises a cathode exhaust stream output by the cathode of the electrolyzer cell.

6 . The fuel cell system according to claim 3 , wherein the hydrogen stream comprises at least 70% hydrogen.

7 . The fuel cell system according to claim 6 , wherein at least a portion of the hydrogen stream is recycled to the anode of the fuel cell.

8 . The fuel cell system according to claim 6 , further comprising:
a methanation catalyst provided downstream of the electrolyzer cell; and a peaker fuel cell, wherein: the methanation catalyst is configured to react with the hydrogen stream such that carbon monoxide is removed from the hydrogen stream and methane is formed; the peaker fuel cell is configured to receive the hydrogen stream from which carbon monoxide was removed and to output a peaker fuel cell exhaust stream; and the peaker fuel cell exhaust stream is recycled to the anode of the electrolyzer cell or the fuel cell, is exported from the fuel cell system, or a combination thereof.

9 . The fuel cell system according to claim 6 , further comprising a proton-membrane exchange fuel cell configured to receive at least a portion of the hydrogen stream, wherein:
the proton-membrane exchange fuel cell is configured to output an exhaust stream; and the gas stream oxidized by the anode gas oxidizer comprises the exhaust stream of the proton-membrane exchange fuel cell.

10 . The fuel cell system according to claim 1 , wherein a third portion of the anode exhaust stream is recycled and mixed, at a location upstream of an inlet of the anode of the fuel cell, with a fuel gas stream comprising natural gas.

11 . The fuel system according to claim 1 , wherein:
the fuel cell is a solid oxide fuel cell, and the electrolyzer cell is a molten carbonate electrolysis cell.

12 . A fuel cell system comprising:
a fuel cell having a cathode and an anode configured to output an anode exhaust stream comprising carbon dioxide, hydrogen, and water; and an electrolyzer cell having a cathode and an anode, wherein: the anode of the electrolyzer cell is configured to receive a first portion of the anode exhaust stream and to generate a hydrogen stream; and the cathode of the electrolyzer cell is configured to output an air stream to the cathode of the fuel cell.

13 . The fuel cell system according to claim 12 , further comprising:
an anode gas oxidizer configured to oxidize a gas stream to remove carbon dioxide and nitrogen therefrom and to output an oxidized exhaust; a heat exchanger configured to receive the air stream and the oxidized exhaust; and a cathode supply line, wherein: the heat exchanger is further configured to transfer heat from the oxidized exhaust to the air stream, and the cathode supply line is configured to supply a heated air stream output from the heat exchanger to the cathode of the fuel cell.

14 . A method of operating a fuel cell system to increase an efficiency thereof, the method comprising:
outputting a first portion of an anode exhaust stream comprising carbon dioxide, hydrogen, and water from an anode of a fuel cell to an electrolyzer cell; removing carbon dioxide and water from the first portion of the anode exhaust stream in an anode of the electrolyzer cell to generate a hydrogen stream and carbonate ions; processing the carbonate ions in a cathode of the electrolyzer cell and outputting an air stream from the cathode of the electrolyzer cell to a cathode of the fuel cell; and oxidizing a gas stream using an anode gas oxidizer to remove carbon dioxide and nitrogen therefrom.

15 . The method according to claim 14 , wherein the gas stream oxidized by the anode gas oxidizer comprises a second portion of the anode exhaust stream.

16 . The method according to claim 14 , further comprising recycling at least a portion of the hydrogen stream to the anode of the fuel cell.

17 . The method according to claim 14 , further comprising:
cooling the hydrogen stream; reacting the cooled hydrogen stream using a methanation catalyst to remove carbon monoxide from the hydrogen stream and to form methane; and after removing carbon monoxide from the hydrogen stream, supplying the hydrogen stream to a peaker fuel cell.

18 . The method according to claim 17 , further comprising recycling a peaker fuel cell exhaust stream to the electrolyzer cell, exporting the peaker fuel cell exhaust stream from the fuel cell system, or a combination thereof.

19 . The method according to claim 14 , further comprising:
receiving a first portion of the hydrogen stream in a proton-membrane exchange fuel cell; and outputting an exhaust stream from the proton-membrane exchange fuel cell, wherein the gas stream oxidized by the anode gas oxidizer comprises the exhaust stream of the proton-membrane exchange fuel cell.

20 . The method according to claim 14 , further comprising recycling a third portion of the anode exhaust stream by mixing, at a location upstream of the anode of the fuel cell, the third portion of the anode exhaust stream with a fuel gas stream comprising natural gas.

Assignees

• Fuelcell Energy Inc

Inventors

• Jahnke Fred C

Classifications

• Y02P90/40

  Fuel cell technologies in production processes · CPC title

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title

• H01M16/003 Primary

  of fuel cells with other electrochemical devices, e.g. capacitors, electrolysers · CPC title

• H01M8/0687

  Reactant purification by the use of membranes or filters · CPC title

• H01M8/0681

  Reactant purification by the use of electrochemical cells · CPC title