DEVICE AND METHOD FOR CLEANING A FLUID FOR THE OPERATION OF A FUEL CELL

Abstract

The present invention relates to a filter unit (100, 301) for filtering a fluid (105) for the operation of a fuel cell. The filter unit (100, 301) comprises at least one filter element (101) filled with a filter material (103) comprising cyclodextrin. The presented Invention also relates to a fuel cell system, to the use of cyclodextrin to filter a fluid for the operation of a fuel cell system, and to a method for operating a fuel cell system.

Claims

1. A filter unit (100, 301) for filtering a fluid (105) for operating a fuel cell (303), wherein the filter unit (100, 301) comprises at least one filter element (101) filled with a filter material (103) which includes cyclodextrin.

2. The filter unit (100, 301) as claimed in claim 1, wherein the filter material (103) comprises at least one material from the following list of materials: alpha-cyclodextrin, beta-cyclodextrin, gamma-cyclodextrin, pulverulent cyclodextrin, polymeric cyclodextrin and pressed cyclodextrin.

3. The filter unit (100, 301) as claimed in claim 1, wherein the filter material (103) comprises, in addition to the cyclodextrin, at least one material from the following list of materials: graphite, graphene, phthalocyanine, silica and foam ceramic.

4. The filter unit (100, 301) as claimed in claim 1, wherein the filter unit (100, 301) comprises at least one interface (200) for applying a vacuum.

5. The filter unit (100, 301) as claimed in claim 1, wherein the filter unit (100, 301) comprises at least one temperature control element (207) for setting a temperature in the filter element (101).

6. A fuel cell system (300), wherein the fuel cell system (300) comprises: a fuel cell stack (303), and at least one filter unit (100, 301) as claimed in claim 1, wherein the at least one filter unit (100, 301) is disposed in a line for supplying a fluid (105) to the fuel cell stack (303) and is configured to clean the fluid (105) of impurities (107).

7. The fuel cell system (300) as claimed in claim 6, wherein the at least one filter unit (100, 301) acts as a pressure reducer and is configured to reduce a pressure at which the fluid flows onto the fuel cell stack (303) to a predefined pressure.

8. The fuel cell system (300) as claimed in claim 6, wherein the fuel cell system (300) is a solid oxide fuel cell system or a membrane fuel cell system.

9. (canceled)

10. A method (400) for operating a fuel cell system (300), wherein the method (400) comprises the following steps: providing (401) at least one filter unit as claimed in claim 1, and operating (403) the fuel cell system (300) by conducting fluid (105) for operating the fuel cell system (300) to the at least one filter unit (100, 301) and conducting fluid (111) cleaned by the at least one filter unit (100, 301) to a fuel cell stack (303) of the fuel cell system (300).

11. The method (400) as claimed in claim 10, wherein the method (400) further comprises: applying a vacuum to the at least one filter unit (100, 301) to clean the filter material (103) of impurities (107), or replacing a filter element (101) of the at least one filter unit (100, 301) with a fresh filter element (101).

12. The filter unit (100, 301) as claimed in claim 2, wherein the filter material (103) comprises, in addition to the cyclodextrin, at least one material from the following list of materials: graphite, graphene, phthalocyanine, silica and foam ceramic.

13. The filter unit (100, 301) as claimed in claim 12, wherein the filter unit (100, 301) comprises at least one interface (200) for applying a vacuum.

14. The filter unit (100, 301) as claimed in claim 13, wherein the filter unit (100, 301) comprises at least one temperature control element (207) for setting a temperature in the filter element (101).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The Figures Show:

[0039] FIG. 1 a possible configuration of the presented filter unit,

[0040] FIG. 2 the filter unit according to FIG. 1 with an interface for applying a vacuum,

[0041] FIG. 3 a possible configuration of the presented fuel cell system,

[0042] FIG. 4 a possible configuration of the method presented.

DETAILED DESCRIPTION

[0043] A filter unit 100 is shown in FIG. 1. The filter unit 100 comprises a filter element 101 filled with filter material 103.

[0044] The filter material 103 consists at least partially of cyclodextrin. In particular, the filter material 103 may comprise alpha-cyclodextrin, beta-cyclodextrin, gamma-cyclodextrin, powdered cyclodextrin, polymeric cyclodextrin and/or pressed cyclodextrin. Additionally, the filter material may include graphite, graphene, phthalocyanine, silica and/or foam ceramic.

[0045] The filter unit 100 is used to filter or clean a fluid 105, in this case a hydrogen gas, which is contaminated with impurities 107, such as hydrocarbons.

[0046] To clean the contaminated fluid 105, the fluid 105 is conducted into the filter unit 100, as indicated by arrow 109.

[0047] The filter material 103, in particular the cyclodextrin in the filter material 103, absorbs the impurities 107 and allows cleaned fluid 111 to pass. Accordingly, the cleaned fluid 111 exits the filter unit 100 filtered, as indicated by arrow 113.

[0048] FIG. 2 shows the filter unit 100 with an interface 200 for applying a vacuum.

[0049] The cyclodextrin or cyclodextrin molecules of the filter material 103 are configured to reversibly bind the impurities inside their ring-shaped structure. Accordingly, cyclodextrin molecules containing impurities can be cleaned of the impurities 107 by a cleaning process, such as by applying a vacuum or negative pressure to the filter element 101, and used for renewed filtering of contaminated fluid 105. For this purpose, the interface 200 can be opened or closed via a valve 201 in order to allow a vacuum provided by an external suction device, for example, to act on the filter material 103.

[0050] Optionally, shut-off valves 203 and 205 may be provided, which may be closed when applying a vacuum at the interface 200, in order to maximize a suction effect of the vacuum on the filter material 103 and, accordingly, on the cyclodextrins, so that the impurities 107 may be released from the cyclodextrins and discharged from the filter unit 100, as indicated by arrow 207.

[0051] A temperature in the filter element 101 can be adjusted by means of an optional temperature control element 209 so that, for example, the filter material 103 or the cyclodextrins can be particularly readily separated from the bound impurities 107. For this purpose, the temperature control element 209 may comprise a heater and/or a cooler or can conduct heat energy provided by an external heater or cooling energy provided by an external cooler to the filter element 101 via a temperature control medium, such as water.

[0052] A fuel cell system 300 is shown in FIG. 3, which comprises a filter unit 301, such as the filter unit 100 shown in FIG. 1, and a fuel cell stack 303.

[0053] To operate the fuel cell system 300, a fluid containing hydrogen is fed from a pressure reservoir into the filter unit 301 and filtered through a filter material of the filter unit 301.

[0054] Accordingly, the filter unit 301 supplies cleaned fluid, i.e. pure hydrogen or substantially pure hydrogen, to the fuel cell stack.

[0055] Due to the physical properties of the filter unit 301, the filter unit 301 acts as a pressure reducer between the pressure reservior and the fuel cell stack 303, so that a pressure reducing valve in the fuel cell system can optionally be dispensed with. In this case, for example, two or more filter units 301 can be arranged in series in order to set a predefined operating pressure for supplying the fuel cell stack 303 with operating fluid.

[0056] In particular, the fuel cell system 300 may be a solid oxide fuel cell system or a membrane fuel cell system.

[0057] FIG. 4 shows a method 400. The method 400 comprises a provision step 401 for providing the presented filter unit to a fuel cell system and an operating step 403 for operating the fuel cell system by conducting fluid for operating the fuel cell system to the filter unit and conducting fluid cleaned by the filter unit to a fuel cell stack of the fuel cell system.

[0058] In an optional maintenance step 405, the filter unit can be cleaned by means of a vacuum or replaced by a fresh filter unit or conditioned with a fresh filter element.