METHOD AND DEVICE FOR ELECTROCHEMICAL HYDROGEN COMPRESSION

Abstract

A method for electrochemical hydrogen compression. The method includes: providing hydrogen gas having a relative humidity RH of 100%; providing inert gas having a relative humidity RH of 100%; mixing the humidified hydrogen gas and the humidified inert gas; electrochemically oxidizing the hydrogen gas at an anode; transporting the protons obtained as a result of the oxidation and at least a portion of the humidified inert gas through a membrane; and electrochemically reducing the protons at a cathode into hydrogen.

Claims

1-13. (canceled)

14. A method for electrochemical hydrogen compression, comprising the following steps: providing hydrogen gas having a relative humidity RH of 100%; providing inert gas having a relative humidity RH of 100%; mixing the humidified hydrogen gas and the humidified inert gas; electrochemically oxidizing the hydrogen gas at an anode; transporting protons obtained as a result of the oxidation through the membrane; and electrochemically reducing the protons at a cathode into hydrogen.

15. The method as recited in claim 14, wherein the mixing of humidified hydrogen gas and humidified inert gas takes place at a mixing ratio of 99:1 to 1:99, based on volume.

16. The method as recited in claim 15, wherein the mixing ratio is 10:90 to 40:60, based on the volume.

17. The method as recited in claim 14, further comprising: setting a hydrogen gas pressure and/or a inert gas pressure to a target pressure of 1 bar to 50 bar.

18. The method as recited in claim 14, wherein the inert gas, after having been transported to the anode, is recycled and made available again, after a humidification to a relative humidity RH of 100%, for mixing with further hydrogen gas, which was brought to a relative humidity RH of 100%.

19. The method as recited in claim 14, further comprising: separating water from the hydrogen obtained at the cathode.

20. The method as recited in claim 19, further comprising: recycling the separated water and supplying the separated water to hydrogen gas and/or inert gas to be humidified.

21. The method as recited in claim 14, wherein the mechanical energy for transporting the humidified inert gas is provided by the hydrogen generated at the cathode.

22. The method as recited in claim 21, further comprising: expanding the hydrogen generated at the cathode at an expansion turbine.

23. A device for electrochemical hydrogen compression, comprising: an anode configured for an electrochemical oxidation of hydrogen gas; a membrane configured to transport protons obtained as a result of the oxidation; a cathode configured for an electrochemical reduction of the protons into hydrogen; a first humidifier configured to humidify the hydrogen gas to be supplied to the anode to a relative humidity of 100%; a first hydrogen supply unit configured to supply hydrogen to the first humidifier; a second humidifier unit configured to humidify inert gas, to be supplied to the anode, to a relative humidity RH of 100%; a first inert gas supply unit configured to supply the inert gas to the second humidifier; a mixing device configured to mix the humidified inert gas and the humidified hydrogen gas; a second hydrogen supply unit configured to supply the humidified hydrogen gas to the mixing device; a second inert gas supply unit configured to supply the humidified inert gas to the mixing device; and a mixing gas supply unit configured to supply the mixture of the humidified hydrogen gas and the humidified inert gas to the anode.

24. The device as recited in claim 23, further comprising: at least one compression device and/or throttle and/or pump configured to set a pressure of the hydrogen gas and/or the inert gas to a target pressure of 1 bar to 50 bar.

25. The device as recited in claim 23, further comprising: a water separator configured to separate water from the hydrogen generated at the cathode.

26. The device as recited in claim 23, further comprising: a water recycling line configured to transport water from the cathode into the first humidifier and/or into the second humidifier.

27. The device as recited in claim 23, further comprising: an expansion turbine configured to generate mechanical energy for transporting the humidified inert gas.

Description

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0041] Exemplary embodiments of the present invention are described hereafter in detail with reference to the figures.

[0042] FIG. 1 shows a method diagram, illustrating method steps of a method for the electrochemical hydrogen compression according to a first specific embodiment of the present invention.

[0043] FIG. 2 shows a schematic view of a device for the electrochemical hydrogen compression according to a second specific embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0044] The figures only represent certain main features of the present invention. Remaining possible features have been omitted for the sake of clarity. Furthermore, identical reference numerals denote identical components.

[0045] As is shown FIG. 1, in accordance with an example embodiment of the present invention, the method includes six method steps.

[0046] In a first method step 100, hydrogen gas having a relative humidity RH of 100% is provided. The hydrogen gas may, e.g., stem from a hydrogen tank or also from a hydrogen-generating reaction system, such as, e.g., an electrolysis device. The hydrogen gas is then, for example, brought to a relative humidity of 100% in a humidifier using water vapor.

[0047] In a second method step 200, which may also run in parallel to first method step 100, inert gas having a relative humidity RH of 100% is provided. Any inert gas and also mixtures of two or more inert gases are possible. Particularly preferably, nitrogen is used as the inert gas. The inert gas may also be humidified in a humidifier.

[0048] In a third method step 300, a mixing of the humidified hydrogen gas and of the humidified inert gas takes place. For this purpose, the humidified hydrogen gas and the humidified inert gas are fed to a mixing device, which in the simplest case encompasses a throttle valve or a mixing valve.

[0049] The mixed gas made up of humidified hydrogen gas and humidified inert gas is then fed to an EHC unit, in which the following method steps are carried out: [0050] 400: electrochemical oxidation of the hydrogen gas at an anode; [0051] 500: transporting the protons obtained as a result of the oxidation through a proton-conductive membrane; and [0052] 600: electrochemical reduction of the protons at a cathode into hydrogen.

[0053] By mixing humidified hydrogen gas having a relative humidity RH of 100% and humidified inert gas having a relative humidity RH of 100%, the membrane of the EHC unit is kept permanently moist, so that the method is also characterized by a permanently high and efficient executability.

[0054] FIG. 2 shows a device 1 for the electrochemical compression of hydrogen according to a second specific embodiment. Device 1 is suitable for carrying out the method illustrated in FIG. 1.

[0055] Device 1 includes an EHC unit 2, which includes an anode 3 for the electrochemical oxidation of hydrogen gas, a membrane 4 for transporting the protons obtained as a result of the oxidation, and a cathode 5 for the electrochemical reduction of the protons into hydrogen. The EHC unit is connected to a voltage source (not shown), a driving force for the passage of the protons through the membrane being generated by the obtained current intensity. The higher the current intensity, the more protons pass through the membrane, and the more hydrogen is generated at the cathode.

[0056] Device 1 furthermore includes a first humidifier 6 for humidifying the hydrogen gas to be supplied to anode 3 to a relative humidity RH of 100%. A first hydrogen supply unit 7 is provided in the process to supply hydrogen, for example from a hydrogen reservoir 8, which is, e.g., a hydrogen tank, to first humidifier 6.

[0057] Moreover, a second humidifier 9 for humidifying the insert gas to be supplied to anode 3 to a relative humidity RH of 100% is provided. A first inert gas supply unit 10 supplies the inert gas to second humidifier 9, e.g., from an inert gas tank 11.

[0058] Device 1 furthermore includes a mixing device 12 which, e.g., encompasses a throttle valve or mixing valve, for mixing the humidified inert gas and the humidified hydrogen gas, a second water supply unit 13 for supplying the humidified hydrogen gas into mixing device 12 and a second inert gas supply unit 14 for supplying the humidified inert gas to mixing device 12 being provided.

[0059] The mixture of the humidified hydrogen gas and the humidified inert gas is then supplied via a mixed gas supply unit 15 to anode 3 via anode input 16.

[0060] The hydrogen generated at cathode 5 may still contain residual water. The hydrogen/water mixture obtained at the cathode may be discharged from cathode 5 via a cathode waste gas line 17 and, for example, be supplied to a water separator 18.

[0061] In water separator 18, the hydrogen/water mixture is separated into pure hydrogen and water, it being possible to supply the hydrogen, e.g., to a hydrogen storage system (not shown). The separated water may, e.g., be supplied to second humidifier 9 via a water recycling line 21. As an alternative or in addition, the separated water may also be supplied to first humidifier 6.

[0062] Inert gas which has not passed through membrane 4 may be supplied to second humidifier 9 again via an anode waste gas line 22, and may thus be recycled.

[0063] In first hydrogen supply unit 7 and in first inert gas supply unit 10, compression devices, such as, e.g., a respective pump 19, 20, may be provided, to set the hydrogen gas pressure and the inert gas pressure to a target pressure of 1 bar to 50 bar.

[0064] Furthermore, the device may include an expansion device (not shown), such as, e.g., an expansion turbine, for generating mechanical energy for transporting the humidified inert gas. The expansion device may be situated in cathode waste gas line 17, for example.

[0065] As a result of mixing humidified inert gas and humidified hydrogen gas in mixing device 12 and supplying the obtained mixed gas having a relative humidity RH of 100%, membrane 4 may be kept moist, in particular, on the anode side, so that EHC unit 2 shows a permanently high performance, and protons may pass through the membrane very well and may be reduced again at the cathode.