Gas-liquid separator for fuel cell system

• US 20030019363A1
• Filed: 09/20/2002
• Published: 01/30/2003
• Est. Priority Date: 10/19/2000
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Grover, Trevor T., Forte, Jameson R.
• Granted Patent: US 6,869,469 B2
• Time in Patent Office: Days
• US Class Current: 96/189
• CPC Class Codes: H01M 8/04291 Arrangements for managing water in solid electrolyte fuel cell systems H01M8/04119 takes precedence
• CPC Class Codes: H01M 8/0612 from carbon-containing material
• 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 water separator especially suitable for use in a vehicular fuel cell system. The separator comprises a housing defining an inlet, an outlet, and a longitudinal through passage extending therebetween. A central shaft extends along the passage and a plurality of modular baffles are stacked on the shaft. Each baffle includes an annular hub portion received on the shaft and a plurality of circumferentially spaced vanes extending outwardly from the hub portion to block a portion of the cross-sectional area of the passage. An actuator drives one end of the shaft and alternate baffles are keyed to the shaft so that actuation of the actuator relatively rotates the modular baffles to selectively vary the cross-sectional blockage defined by the baffles. The actuator is actuated in response to sensed parameters of the cell such as the humidity of a compressed gas stream delivered to the cell, the mass flow rate of the gas stream, the temperature and pressure within the cell, and the electrical current produced by the cell. With this arrangement and with these parameters, the separator may be instantaneously and continuously adjusted to provide a degree of restriction customized to the amount of water entrained in the gas streams being handled by the separator. In an alternate embodiment, alternate baffle modules stacked on the shaft are relatively rotated to vary the restriction provided by the separator utilizing bimetallic coils between the shaft and the hub of selected modules.

Claims

1. A gas-liquid separator comprising:

a housing defining an inlet, an outlet, and a longitudinal flow through passage extending between the inlet and the outlet;

a plurality of baffles arranged in longitudinally spaced serial relation in and along the passage and each blocking a portion of the cross section of the passage; and

means mounting the baffles for relative movement to selectively vary the composite cross-sectional blockage defined by the baffles.

2. A gas-liquid separator according to claim 1 wherein each baffle is mounted for rotation about a central axis extending through the passage.

3. A gas-liquid separator according to claim 2 wherein each baffle includes a central hub positioned on the axis and a plurality of circumferentially spaced vanes extending radially outwardly from the hub.

4. A gas-liquid separator according to claim 3 wherein the vanes of each baffle block a given percentage of the cross-sectional area of the passage so that first and second successive baffles in the passage may be relatively rotated to define a composite cross-sectional blockage varying from the given percentage of the cross-sectional passage area to a larger percentage of the cross-sectional passage area.

5. A gas-liquid separator according to claim 4 wherein the vanes of each baffle block approximately one half of the cross-sectional area of the passage so that first and second successive baffles in the passage may be relatively rotated to define a composite cross-sectional blockage varying from approximately one half of the cross-sectional passage area to essentially all of the cross-sectional passage area.

6. A gas-liquid separator according to claim 1 wherein the separator further includes means operative to relatively move the baffles.

7. A gas-liquid separator according to claim 6 wherein the moving means comprises bimetal means drivingly associated with the baffles and operative to relatively move the baffles in response to environmental temperature variations.

8. A gas-liquid separator according to claim 6 wherein:

the separator is intended for use in conjunction with a fuel cell; and

the moving means comprises an actuator drivingly associated with the baffles and means operative to generate a control signal for delivery to the actuator reflecting sensed parameters of the fuel cell.

9. A gas-liquid separator according to claim 8 wherein the sensed parameters of the fuel cell include one or more of the humidity of a compressed gas stream delivered to the fuel cell, the mass flow rate of the gas stream, the temperature and pressure within the fuel cell, and the electrical current produced by the fuel cell.

10. A gas-liquid separator according to claim 4 wherein:

the separator includes a central shaft positioned on the axis; and

the central hubs are annular and are fitted over the shaft in serial stacked relation.

11. A gas-liquid separator according to claim 10 wherein:

the separator further includes an actuator rotatably driving the shaft; and

selected hubs of selected baffles are keyed to the shaft so that rotation of the shaft by the actuator relatively rotates the baffles.

12. A gas-liquid separator according to claim 10 wherein the baffles are modular units that may be readily slipped on and off of the shaft to vary the number of baffles in the separator and thereby vary the separation efficiency of the separator.

13. A gas-liquid separator according to claim 12 wherein the housing is sectional and includes modular components which may be interchanged to vary the size of the housing in accordance with the number of modules employed.

14. A gas-liquid separator according to claim 1 wherein the gas-liquid separator comprises a water separator.

15. A fuel cell system including a fuel cell receiving an H₂rich feed and a compressed gas stream and operative to generate an electrical output, a cathode effluent, and an anode effluent, and a gas-liquid separator receiving the cathode effluent from the fuel cell, characterized in that the gas-liquid separator comprises:

a housing defining an inlet, an outlet, and a longitudinal flow through passage extending between the inlet and the outlet;

a plurality of baffles arranged in longitudinally spaced serial relation in and along the passage and each blocking a portion of the cross section of the passage; and

means mounting the baffles for relative movement to selectively vary the composite cross-sectional blockage defined by the baffles.

16. A fuel cell system according to claim 15 wherein each baffle is mounted for rotation about a central axis extending through the passage.

17. A fuel cell system according to claim 16 wherein each baffle includes a central hub positioned on the axis and a plurality of circumferentially spaced vanes extending radially outwardly from the hub.

18. A fuel cell system according to claim 17 wherein the vanes of each baffle block a given percentage of the cross-sectional area of the passage so that first and second successive baffles in the passage may be relatively rotated to define a composite cross-sectional blockage varying from the given percentage of the cross-sectional passage area to a larger percentage of the cross-sectional passage area.

19. A fuel cell system according to claim 18 wherein the vanes of each baffle block approximately one half of the cross-sectional area of the passage so that first and second successive baffles in the passage may be relatively rotated to define a composite cross-sectional blockage varying from approximately one half of the cross-sectional passage area to essentially all of the cross-sectional passage area.

20. A fuel cell system according to claim 15 wherein the separator further includes means operative to relatively move the baffles.

21. A fuel cell system according to claim 20 wherein the moving means comprises bimetal means drivingly associated with the baffles and operative to relatively move the baffles in response to environmental temperature variations.

22. A fuel cell system according to claim 20 wherein the moving means comprises an actuator drivingly associated with the baffles and means operative to generate a control signal for delivery to the actuator reflecting sensed parameters of the fuel cell.

23. A fuel cell system according to claim 22 wherein the sensed parameters of the fuel cell include one or more of the humidity of the compressed gas stream delivered to the fuel cell, the mass flow rate of the gas stream, the temperature and pressure within the fuel cell, and the electrical current produced by the fuel cell.

24. A fuel cell system according to claim 18 wherein:

the separator includes a central shaft positioned on the axis; and

the central hubs are annular and are fitted over the shaft in serial stacked relation.

25. A fuel cell system according to claim 24 wherein the vanes of each baffle block a given percentage of the cross-sectional area of the passage so that first and second successive baffles in the passage may be relatively rotated to define a composite cross-sectional blockage varying from the given percentage of the cross-sectional passage area to a larger percentage of the cross-sectional passage area.

26. A fuel cell system according to claim 25 wherein the vanes of each baffle block approximately one half of the cross-sectional area of the passage so that first and second successive baffles in the passage may be relatively rotated to define a composite cross-sectional blockage varying from approximately one half of the cross-sectional passage area to essentially all of the cross-sectional passage area.

27. A fuel cell system according to claim 24 wherein:

the separator further includes an actuator rotatably driving the shaft; and

selected hubs are keyed to the shafts so that rotation of the shaft by the actuator relatively rotates the baffles.

28. A fuel cell system according to claim 15 wherein a separator as described is also provided to receive the anode effluent from the fuel cell.

29. A fuel cell system according to claim 15 wherein a separator as described is also provided to receive the H₂ rich feed upstream of the fuel cell.

30. A fuel cell system according to claim 15 wherein the gas-liquid separator comprises a water separator.