Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B15/00—Operating or servicing cells
  • C25B15/08—Supplying or removing reactants or electrolytes; Regeneration of electrolytes
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
  • C25B9/70—Assemblies comprising two or more cells
  • C25B9/73—Assemblies comprising two or more cells of the filter-press type
  • C25B9/77—Assemblies comprising two or more cells of the filter-press type having diaphragms

Definitions

• the invention relates to an electrolysis device with a number of membrane electrolysis cells, each of which comprises a membrane provided on both sides with a contact layer.
• an electrolysis device In an electrolysis device, a medium is electrolytically decomposed by applying a supply voltage between an anode and a cathode. When water is used as the medium, hydrogen and oxygen are formed. Such an electrolysis device can thus be used to generate hydrogen and / or oxygen as required.
• an electrolysis device can be provided for the need-based gassing of the primary cooling circuit of a pressurized water reactor with hydrogen.
• An electrolysis device can be designed as a membrane electrolyzer.
• the electrolysis device comprises a number of membrane electrolysis cells in which the operating principle of a fuel cell is reversed.
• the principle of operation of a fuel cell is described, for example, in the article "Fuel cells for electrical traction", K. Straßer, VDI reports, No. 912 (1992), pages 125ff.
• a membrane electrolysis cell the water provided as the medium is fed to a membrane arranged between the anode and the cathode, in particular to a cation exchange membrane provided as an electrolyte.
• the membrane is usually provided on both sides with a contact layer, the first contact layer serving as the anode and the second contact layer as the cathode.
• Such a membrane electrolysis cell is characterized by a particularly compact design, so that an electrolysis unit unit can be accommodated with a number of membrane electrolysis cells in a particularly narrow space.
• an electrolysis device As a hydrogen generator in the industrial area or in the power plant area, it is necessary to design its production capacity with regard to the underlying need for hydrogen.
• the design of the electrolysis device as a membrane electrolyzer which is desirable in terms of structural advantages, may be unsuitable, in particular for applications with a comparatively high hydrogen requirement.
• the invention is therefore based on the object of specifying an electrolysis device with a number of membrane electrolyzers of the type mentioned above, which, with its compact design, is also suitable for comparatively high hydrogen production rates and can therefore be used particularly flexibly.
• each contact plate is arranged on each contact layer, each contact plate having a channel system for transporting water and / or gas on its surface facing the associated contact layer.
• the invention is based on the consideration that a membrane electrolyser, which is also suitable for high hydrogen production rates, should have a number of membrane electrolysis cells with membranes with particularly large dimensions. Even with such dimensioning of the membranes, reliable feeding of the membranes with the medium to be decomposed, in particular with water, should be ensured.
• a reliable transport system for the medium and also for the gas generated in the electrolysis process is provided for each membrane of the electrolysis device and is also suitable for large-area membranes.
• a special one A compact design can be achieved by integrating the transport system into the contact plates provided for the electrical contacting of the electrodes attached to the membranes.
• each contact plate is preferably designed in the form of concentric circular segments. It has been found that with such an arrangement of the channel system, a particularly inexpensive and reliable supply to all active areas of a membrane can be achieved.
• the membrane electrolysis cells are expediently connected electrically in a row.
• a porous printed circuit board is arranged between each contact layer and the contact plate assigned to it.
• a porous printed circuit board which can be formed, for example, from titanium, on the one hand establishes reliable electrical contact between the contact layer and the associated contact plate, on the other hand an unimpeded passage of the medium to be decomposed to the membrane and of the electrolytically generated gas into the Channel system is guaranteed.
• the porous printed circuit board additionally favors the distribution of the supplied medium on the membrane.
• the channel systems of the contact plates arranged on both sides of a membrane can be fed independently of one another with a medium, in particular with water or deionized water.
• that contact layer of the membrane which is provided as the anode for the electrolysis process can be supplied with a different medium than the contact layer which is provided as the cathode.
• the electrolysis device can thus be used particularly flexibly.
• the contact layer of the membrane provided as the cathode bran can be supplied with coolant guided in the primary circuit of a nuclear plant, whereas deionate can be supplied to the membrane as the anode contact layer.
• Such an electrolysis device can thus be used as a hydrogen generator for the reactor coolant, which is integrated directly into the coolant circuit of a nuclear plant.
• the channel systems of the contact plates arranged on both sides of a membrane are expediently connected to gas discharge systems which are kept separate from one another.
• the membrane electrolysis cells are expediently arranged in a stack shape within a housing, the housing having one on each end face
• Locking element for bracing the membrane electrolysis cells together. Adjacent membrane electrolysis cells can be pressed flat against one another by means of the locking elements, so that a particularly reliable conductive connection between each contact layer and the contact plate assigned to it is ensured.
• the contact layers of one or each membrane are preferably electrically connected to an analysis unit which determines the decay time of a voltage signal of this membrane when the membrane's power supply is switched off.
• an analysis unit which determines the decay time of a voltage signal of this membrane when the membrane's power supply is switched off.
• the membrane electrolysis cell can thus be identified in a particularly simple manner.
• a sensor for determining a gas purity is connected to the analysis unit.
• a prediction of the future operational reliability of the respective membrane can be derived in a particularly simple manner from the statement about the decay time of a membrane together with the statement about the gas purity.
• the electrolysis device can thus be operated particularly reliably even when malfunctions of individual membrane electrolysis cells occur.
• a defective membrane electrolysis cell can be short-circuited so that it no longer makes a contribution to gas production, the functionality of intact membrane electrolysis cells not being impaired.
• the advantages achieved by the invention consist in particular in that the channel systems provided in the contact plates ensure reliable and large-area supply of the medium to be electrolytically decomposed to the membranes with a particularly compact design.
• the membrane electrolysis cells can be operated independently of one another, so that the functionality of the electrolysis device is maintained even if individual membrane electrolysis cells fail. By determining the decay At the time of a voltage signal on a selected membrane analysis unit, a defective membrane electrolysis cell can also be detected in a particularly simple manner. In the event of operational malfunctions, a defective membrane electrolysis cell can thus be uncoupled in a particularly simple manner, the operation of the electrolysis device with the remaining intact membrane electrolysis cells being able to be maintained.
• FIG. 1 shows an electrolysis device in longitudinal section
• FIG. 2 shows the electrolysis device in cross section
• Figure 3 schematically shows a gassing device for a subsystem of a technical system.
• the electrolysis device 1 according to FIG. 1 is designed as a membrane electrolyser and comprises a number of membrane electrolysis cells 2 which are electrically connected in series. In the exemplary embodiment according to FIG. 1, four membrane electrolysis cells 2 connected in series are shown; however, any other number of membrane electrolysis cell 2 can also be provided.
• Each membrane electrolysis cell 2 has a membrane 4 designed as a cation exchange membrane as an electrolyte for water as the medium to be decomposed.
• the membrane 4 of each membrane electrolysis cell 2 is provided on both sides with a contact layer, not shown.
• the two contact layers of a membrane 4 serve as electrodes during the electrolysis process.
• the contact layer provided as the cathode of each membrane 4 is formed from platinum.
• the contact layer of each membrane 4 provided as the anode however, mainly consists of iridium.
• a contact plate 5 is arranged on each contact layer of each membrane 4. Each contact layer is electrically connected to its associated contact plate 5 via a porous circuit board 6.
• the porous printed circuit board 6, which can be manufactured, for example, on a titanium basis, is arranged between the contact layer and the contact board 5 assigned to it.
• the membrane electrolysis cells 2, each formed from a membrane 4, two printed circuit boards 6 and two contact plates 5, are arranged in a stack in the form of a housing 8. Adjacent contact plates 5 of different membrane electrolysis cells 2 are electrically separated from one another by an insulator plate 9. The series connection of the membrane electrolysis cells 2 is effected by an external line system, not shown in detail. Alternatively, adjacent contact plates 5 of different membrane electrolysis cells 2 can also be in direct electrical contact with one another or can also be embodied in one piece.
• the housing 8 has at its end face 10 each as
• Locking element 12 provided screw for clamping the membrane electrolysis cells 2 together.
• Each contact plate 5 is, as shown in FIG. 2 with the aid of the electrolysis device 1 shown in cross section, approximately circular and has a channel system 14 on its surface facing the associated contact layer.
• the channel system 14 is formed from m the respective contact plate 5 projecting depressions, the m shape of concentric circular segments on the surface of each because contact plate 5 are arranged.
• the channel system 14 of each contact plate 5 is provided for the transport of the medium to be decomposed electrolytically to the respective membrane 4.
• the channel system 14 of each contact plate 5 is connected to a supply system for an electrolysis medium.
• a discharge system for gas or for gas-mixed electrolysis medium is connected to the channel system 14 of each contact plate 5.
• the electrolysis device 1 is designed in such a way that the channel systems 14 of the contact plates 5 arranged on both sides of a membrane 4 can be fed with a medium independently of one another.
• the medium or also a gas released during electrolysis can be removed independently of one another from the channel systems 14 of the contact plates 5 arranged on both sides of a membrane 4.
• the channel systems 14 of all contact plates 5, which are assigned to a contact layer of a membrane 4 provided as a cathode are connected on the input side to a common supply system 16 and on the output side to a common discharge system 18.
• the channel systems 14 of those contact plates 5 which are assigned to a contact layer of a membrane 4 provided as an anode are connected on the input side to a supply system 20 which is independent of the supply system 16 and on the output side to a discharge system 22 which is independent of the discharge system 18.
• a supply system 20 which is independent of the supply system 16
• a discharge system 22 which is independent of the discharge system 18.
• the electrolysis device 1 can thus be used particularly flexibly.
• the electrolysis device 1 can be integrated directly into a coolant circuit of a nuclear plant, the contact layers provided as cathodes being directly connected to the reactor coolant.
• tel are feeds inexhaustibly as electrolysis medium, and wherein the enriched with hydrogen from the electrolysis Reaktorkühlmit ⁇ tel is returned directly into the coolant circuit of the nuclear facility.
• the contact layers provided as the anode can be supplied with deionized water.
• FIG. 3 schematically shows a gassing system 28 for a technical system, in particular for the primary circuit of a pressurized water reactor.
• the gassing system 28 comprises, as a hydrogen generator, the electrolysis device 1, the feed and discharge systems 16, 18, 20, 22 of which are connected to the technical system in a manner not shown.
• the electrolysis device 1 also includes an analysis unit 30. The contact layers of each membrane 4 are electrically connected to the analysis unit 30.
• the analysis unit 30 is designed to determine the decay time of a voltage signal of this membrane 4 after the power supply to a membrane 4 has been switched off. From the decay time of the voltage signal, conclusions can be drawn in the analysis unit 30 about the functionality of the respective membrane 4. If the membrane 4 is intact, the respective membrane electrolysis cell 2 should act as a fuel cell for a short time after the power supply has been switched off until the gases released by it previously by electrolysis are removed. Therefore, if the membrane 4 is intact, the voltage signal dropping at it should initially be constant for a short time before it begins to decay. If the membrane 4 is defective, for example as a result of hole formation, the By contrast, the voltage decays immediately after the power supply is switched on, so that an intact from a defective membrane 4 can be distinguished by the analysis unit 30.
• a sensor 32 for determining a gas purity is connected in the discharge systems 18 and 22 for each membrane 4.
• the sensors 32 are also connected to the analysis unit 30.
• Reliable cooling of the electrolysis device 1 during its operation is ensured by the selection of a suitable water throughput through the membrane electrolysis cells 2.
• the medium to be moved, which is supplied to the electrolysis device 1, serves as the cooling medium.
• further cooling devices for the housing 8, for example in the form of cooling fins, can be provided.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
• Electrodes For Compound Or Non-Metal Manufacture (AREA)

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Citations (4)

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• 1997
  • 1997-07-09 DE DE19729429A patent/DE19729429C1/de not_active Expired - Fee Related
• 1998
  • 1998-05-20 TW TW087107792A patent/TW495562B/zh not_active IP Right Cessation
  • 1998-06-26 ES ES98941241T patent/ES2167922T3/es not_active Expired - Lifetime
  • 1998-06-26 DE DE59802319T patent/DE59802319D1/de not_active Expired - Lifetime
  • 1998-06-26 WO PCT/DE1998/001770 patent/WO1999002761A1/de active IP Right Grant
  • 1998-06-26 JP JP50797399A patent/JP3748896B2/ja not_active Expired - Fee Related
  • 1998-06-26 EP EP98941241A patent/EP0932708B1/de not_active Expired - Lifetime
• 2001
  • 2001-01-17 US US09/761,237 patent/USRE38066E1/en not_active Expired - Lifetime

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