Electrolysis module and electrolyser

Abstract

The invention relates to an electrolysis module (1) for alkaline hydrogen electrolysis, comprising an anode (2), a cathode (3) and a separating layer (4) which is arranged between the anode (2) and the cathode (3), two electrically insulating and substantially structurally identical support frames (10, 10') which are connected to one another at their edges, wherein the anode (2) is connected to the first support frame (10), and the cathode (3) is connected to the second support frame (10') so that an anode chamber (6) and a cathode chamber (7) are formed, wherein, in each of the anode-side support frame (10) and the cathode-side support frame (10'), two inflow manifolds (8, 8') for supplying electrolysis medium and two outflow manifolds (9, 9') for discharging electrolysis and product medium are provided, and wherein the support frames (10, 10') are arranged in such a way that the inflow manifolds (8, 8') and the outflow manifolds (9, 9') of adjacent support frames (10, 10') are arranged substantially congruently, wherein, in each of the support frames (10, 10'), one of the inflow manifolds (8, 8') has a first magnetic current sensor (12, 12') and one of the outflow manifolds (9, 9') has a second magnetic current sensor (13, 13').

Description

[0001] 65208 / AG / VH

[0002] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)

[0003] Electrolysis module and electrolyzer

[0004] The invention relates to an electrolysis module and an electrolyzer with such an electrolysis module.

[0005] Electrolyzers for alkaline hydrogen electrolysis are known from the prior art. These serve for the electrochemical decomposition of an aqueous electrolysis medium into hydrogen and oxygen and comprise an electrolysis cell through which the electrolysis medium flows, with an electrical anode in an anode chamber and an electrical cathode in a cathode chamber. The anode chamber and the cathode chamber are separated by a permeable membrane (diaphragm) and are surrounded by the aqueous electrolysis medium. Applying a voltage causes hydroxide ions (OH-) and gaseous hydrogen (H2) to form at the cathode. The negatively charged hydroxide ions move through the membrane from the cathode chamber to the anode chamber, where gaseous oxygen (O2) and water are subsequently formed. The generated hydrogen and oxygen are separated from the electrolysis medium in separators and can be further used as product gases. 65208 / AG / VH

[0006] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)

[0007] Alkaline electrolysis offers a long service life and enables high system output. Current state-of-the-art electrolyzers are based on single cells that operate at atmospheric pressure or slight overpressure and are interconnected to form larger systems, or pressurized electrolyzers designed as integrated multi-cell stacks that operate at temperatures from 60°C to 90°C and pressures from 10 bar to approximately 30 bar.

[0008] Due to the electrical conductivity of the electrolysis medium, ionic currents flow past the actual electrolysis cell via the manifolds (inlet and outlet) during the operation of an alkaline electrolyzer. This phenomenon of so-called stray currents reduces the electrochemical efficiency of the electrolysis, as the currents bypassing the reaction cannot be used for electrolysis and thus for the production of hydrogen and oxygen. This is particularly problematic in the case of pressurized alkaline electrolyzers, since the produced gas is highly compressed. This effectively increases the electrical conductivity of the outlet, meaning that the relative volume fraction of electrically conductive alkali at the outlet is higher compared to the compressed gas fraction.

[0009] In the operation of the electrolyzer, it is important to know the proportion of stray currents in order to be able to estimate the Faraday efficiency, i.e., the ratio of the current usable for electrolysis to the total current supplied, of the electrolyzer.

[0010] Especially under partial load, Faraday efficiency typically decreases. To still enable efficient operation, it is important to know the stray currents.

[0011] Publication WO2023156551 A1 describes a method for the non-contact measurement of current densities in an electrolyzer stack and the construction of a corresponding electrolyzer. Sensors are used that detect changes in magnetic flux and are placed in specially designed recesses within the electrolyzer's insulation plates. This means that the sensors are located at the end of a manifold. Information about stray currents can therefore only be obtained for the entire electrolyzer stack. 65208 / AG / VH

[0012] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)

[0013] The purpose of the invention is now to at least partially solve the aforementioned problems.

[0014] One object of the present invention is to determine the efficiency, in particular the Faraday efficiency, of the electrolyzer and / or the individual electrolysis cells. A further object of the invention may be the improved control of the electrolyzer during operation.

[0015] These and other tasks are solved by an electrolysis module according to claim 1 and an electrolyzer according to claim 8.

[0016] An electrolysis module according to the invention for alkaline hydrogen electrolysis comprises an anode, a cathode, and a substantially ion-permeable and electrically insulating separating layer arranged between the anode and the cathode. The electrolysis module further comprises two electrically insulating and substantially identical support frames connected to each other at their edges. The anode is connected to the first support frame, and the cathode is connected to the second support frame, thus forming an anode compartment and a cathode compartment.

[0017] The anode-side and cathode-side support frames each have two manifold inlets for supplying the electrolysis medium and two manifold outlets for draining the electrolysis and product media. The support frames are arranged such that the manifold inlets and outlets of adjacent support frames are essentially congruent. Each support frame has one manifold inlet and one manifold outlet with a second magnetic current sensor.

[0018] Such an electrolysis module allows the stray currents and thus the efficiency during operation of individual electrolysis modules or electrolysis cells, especially in contactless applications, to be determined. 65208 / AG / VH

[0019] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)

[0020] Alkaline hydrogen electrolysis can involve electrolysis using aqueous potassium hydroxide (KOH) or aqueous sodium hydroxide (NaOH) solution as the medium. The medium thus includes the alkalis KOH and NaOH, the gases H₂ and O₂, and mixtures of these substances.

[0021] The electrolysis module can be used to build an electrolysis stack. The electrolysis module can also be designed as a self-contained electrolysis cell.

[0022] The electrolysis module is preferably designed as a zero-gap system. The zero-gap system allows direct contact between the electrodes and the interface, resulting in a higher current density (e.g., up to 1000 mA / cm²). 2 This is possible more so than with electrolysis cells where the electrodes are arranged further apart. This design allows for a compact construction and minimizes overvoltages.

[0023] The ion-permeable separating layer is electrically insulating to prevent short circuits between the electrodes. The separating layer is preferably 0.05 mm to 1 mm thick and permeable. It can be configured as a permeable membrane or a diaphragm. Ionic permeability is achieved by the alkali penetrating the separating layer. Gas cannot diffuse through the separating layer due to the polarity of the material, as the separating layer essentially repels nonpolar compounds such as H₂ and O₂. However, OH⁻ ions can diffuse through the separating layer. Gases can also diffuse through the separating layer in dissolved form, but not in gaseous form, as long as a certain driving pressure gradient is not exceeded.

[0024] The separating layer can be, for example, a textile fabric made of plastic fibers with or without an additional hydrophilic coating. Alternatively, a polyphenylene sulfide fabric coated with a mixture of a polymer (e.g., polysulfone) and zirconium oxide (ZrÜ2) can also be used as the separating layer. 65208 / AG / VH

[0025] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)

[0026] The support frames of the electrolysis module can be connected to each other, for example, by screw connections. The depth of a support frame can range from approximately 1 cm to approximately 10 cm. This creates a stable support frame suitable for absorbing the radial compressive forces present inside the electrolysis module. The support frame can optionally be designed to be essentially ring-shaped. However, it can also be square or rectangular. For better absorption of radial compressive forces, a ring-shaped support frame is preferred, especially for larger dimensions. A circumferential plastic seal may be provided to seal the support frames.

[0027] The anode can comprise nickel or a nickel alloy, with or without a coating. The cathode can also comprise nickel or a nickel alloy, with or without a coating. The coatings can include non-noble metals or minerals, as well as noble metals such as platinum, ruthenium, or indium. The electrodes are preferably porous to allow control over the reaction distribution and the transport of substances.

[0028] According to the invention, it can be provided that in the support frame each of the manifold leads has a module lead into the anode space or cathode space, and each of the manifold leads has a module lead out of the anode space or cathode space, wherein the current sensors are arranged in a ring shape around those manifold leads and manifold leads that do not have a module lead or module lead.

[0029] This allows the module supply line, module discharge line, and magnetic current sensors to be positioned at a sufficient distance from each other. Furthermore, this allows the magnetic current sensor to be designed as a rotating magnetic ring core for inductive current measurement. It also makes it easier to arrange the magnetic current sensors with electrical insulation. 65208 / AG / VH

[0030] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)

[0031] According to the invention, the manifold inlets and outlets can be axially extending and preferably circular recesses in the support frame. This saves material and space for additional lines. The recesses can be joined together to form a liquid-tight line.

[0032] According to the invention, the support frames can be made of or comprise plastic. The plastic is preferably non-conductive. This results in an electrically insulating support frame. Furthermore, the support frame can be lighter compared to conventional metal support frames. The plastic is essentially corrosion-resistant under operating conditions. Suitable plastics include, for example, polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), or similar materials, optionally with or without glass fiber reinforcement.

[0033] According to the invention, the current sensors can be designed for galvanically isolated measurement of the electric current flowing through the manifold leads and manifolds, and a transmission element is provided for wireless or wired transmission of the measured values.

[0034] This allows signals from the collective supply lines and the collective output lines to be independently detected and / or processed by the magnetic current sensors.

[0035] The magnetic current sensor can, for example, consist of an iron core and a Hall effect sensor. The magnetic current sensor can optionally be arranged within the support frame and spatially separated from the manifold inlets and outlets by a material web that allows for the installation of a suitable seal. 65208 / AG / VH

[0036] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)

[0037] According to the invention, it can be provided that an electrically conductive end plate is arranged in a liquid-tight manner on one or both support frames, wherein the end plate has recesses for the manifold inlets and manifold outlets.

[0038] The electrolysis module can, for example, be designed as a single cell with an end plate attached to each of the support frames. An end plate can also separate two or more electrolysis modules arranged side by side.

[0039] The end plate can be made of alkali-resistant metallic sheet metal with a thickness of approximately 0.8 mm to approximately 1.2 mm, preferably approximately 1.0 mm. The end plate can comprise or consist of alkali-resistant stainless steel, nickel, or a nickel alloy.

[0040] According to the invention, the electrolysis medium can be a potassium hydroxide solution KOH or a sodium hydroxide solution NaOH with concentrations in the range of 10-30% by mass.

[0041] According to the invention, an electrolyzer can further be provided which comprises several electrolysis modules according to the invention, wherein the individual electrolysis modules are arranged in series as an electrolysis stack such that the manifold inlets and manifold outlets run congruently through the entire electrolysis stack.

[0042] This saves space and avoids the need for complex piping. The stray currents of individual electrolysis modules or electrolysis cells within an electrolyzer can be determined. From this, conclusions can be drawn about the efficiency of individual cells and the entire electrolyzer during operation.

[0043] The resulting electrolysis stack can be positioned between a positive electrical pole and a negative electrical pole. 65208 / AG / VH

[0044] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)

[0045] The electrolysis modules of the electrolyzer may be arranged between two solid end plates. Insulating elements may be arranged between the end plates and the poles.

[0046] The end plates are preferably clamped firmly by several tie rods.

[0047] According to the invention, it can be provided that the electrolysis modules are under a pressure of over 10 bar, preferably about 30 bar.

[0048] The electrolysis modules are preferably separated from each other by end plates. A large number of electrolysis modules can be connected in series, in particular between 100 and 200.

[0049] The invention will now be explained in more detail using non-exclusive exemplary embodiments.

[0050] They show:

[0051] Fig. 1a shows a schematic oblique view of an embodiment of an electrolysis module according to the invention;

[0052] Fig. 1b shows a sectional view AA of the electrolysis module from Fig. 1a;

[0053] Fig. 1c shows a sectional view BB of the electrolysis module from Fig. 1a;

[0054] Fig. 1d shows a schematic oblique view of an embodiment of the electrolysis module according to the invention as shown in Fig. 1a without a cover plate;

[0055] Fig. 2a shows a schematic cross-section of an electrolyzer through the electrolysis modules arranged in series according to Fig. 1b;

[0056] Fig. 2b shows the schematic current distribution in an electrolyzer according to Fig. 2a in the manifold leads of the electrolysis modules;

[0057] Fig. 2c shows the schematic current distribution in an electrolyzer according to Fig. 2a in the manifold leads of the electrolysis modules.

[0058] Fig. 1a shows a schematic oblique view of an embodiment of an electrolysis module 1 according to the invention. The electrolysis module 1 has two support frames 10, 10' which are ring-shaped. 65208 / AG / VH

[0059] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)

[0060] The support frames 10, 10' are made of an electrically insulating material, in this case a plastic, preferably PEEK. The support frames 10, 10' are essentially identical in construction and are connected to each other at their edges. Furthermore, liquid-tight end plates 5 are arranged on the outer sides of the support frames 10, 10'. For the sake of clarity, a diagram of the required seals has been omitted.

[0061] In the support frames 10, 10' and in the end plates 5, two manifold inlets 8, 8' and two manifold outlets 9, 9' for the supply and discharge of electrolysis medium are arranged congruently. In this embodiment, one manifold inlet 8, 8' is arranged at the outer edge of the support frame 10, 10' opposite one manifold outlet 9, 9'. The support frames 10, 10' are also arranged such that the manifold inlets 8, 8' and the manifold outlets 9, 9' of adjacent support frames 10, 10' can be arranged substantially congruently. The manifold inlets 8, 8' and manifold outlets 9, 9' are formed as axially extending circular recesses in the support frame 10, 10' and in the end plate 5.

[0062] Figures 1b and 1c show schematic cross-sectional views along sections AA and BB of the electrolysis module 1 of Figure 1a. The electrolysis module 1 has two annular support frames 10, 10'. Two manifold inlets 8, 8' and two manifold outlets 9, 9' for the supply and discharge of electrolysis medium are arranged congruently within each support frame 10, 10'. In this embodiment, one manifold inlet 8, 8' is located on the outer circumference of each support frame 10, 10' opposite one manifold outlet 9, 9'. The support frames 10, 10' are also arranged such that the manifold inlets 8, 8' and the manifold outlets 9, 9' of adjacent support frames 10, 10' are substantially congruent. The collecting inlets 8, 8' and collecting outlets 9, 9' are designed as axially extending circular recesses.

[0063] Fig. 1b shows an electrolysis module 1 with an anode 2 connected to a first support frame 10 and a cathode 3 connected to the second support frame 10'. 65208 / AG / VH

[0064] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)

[0065] An electrically insulating separating layer 4 is arranged between the anode 2 and the cathode 3. The separating layer 4 is designed as a diaphragm.

[0066] The support frame 10 and the anode 2 form an anode chamber 6. A liquid-tight end plate 5 is arranged on the support frame 10, so that the anode chamber 6 is bounded by the support frame 10, the anode 2, and the end plate 5. The end plate 5 is designed as a thin, electrically conductive metal sheet.

[0067] The support frame 10' and the cathode 3 form a cathode chamber 7. A liquid-tight end plate 5 is arranged on the support frame 10', so that the cathode chamber 7 is bounded by the support frame 10', the cathode 3, and the end plate 5. The end plate 5 is designed as a thin, electrically conductive metal sheet.

[0068] A manifold inlet 8 and a manifold outlet 9 run through the support frames 10, 10' in section AA. The manifold inlet 8 and the manifold outlet 9 are formed by mutually facing, circular recesses in the support frames 10, 10' and the end plates 5.

[0069] The anode-side support frame 10 has a manifold 8. A first magnetic current sensor 12 is arranged around the manifold 8 in the support frame 10. The manifold 8 has a module supply line 14' in the cathode-side support frame 10', so that electrolysis medium can be directed into the cathode chamber 7.

[0070] In the anode-side support frame 10, the manifold 9 has a module manifold 15 for draining the electrolysis medium and the produced gas O2. In the cathode-side support frame 10', a second magnetic current sensor 13' is arranged around this manifold 9.

[0071] Fig. 1c shows section BB of the electrolysis module 1. A manifold inlet 8' and a manifold outlet 9' run through the support frames 10, 10' in section BB. 65208 / AG / VH

[0072] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)

[0073] The collecting inlet 8' and the collecting outlet 9' are formed by mutually facing, circular recesses in the support frames 10,10' and the end plates 5.

[0074] The cathode-side support frame 10' has a manifold 8'. A first magnetic current sensor 12' is arranged around this manifold 8' in the support frame 10'. The manifold 8' has a module supply line 14 in the support frame 10, so that electrolysis medium can be directed into the anode compartment 6.

[0075] In the cathode-side support frame 10', the manifold 9' has a module manifold 15' for draining the electrolysis medium and the produced gas H2. In the anode-side support frame 10, a second magnetic current sensor 13 is arranged around this manifold 9'.

[0076] Fig. 1d shows a schematic representation of an electrolysis module 1 according to Fig. 1a without end plates 5, looking towards the anode compartment 6 with the internal anode 2. Collective inlets 8, 8' and collector outlets 9, 9' run through the support frames 10, 10' in the lower region and through the support frames 9, 10' in the upper region. The collective inlets 8, 8' and the collector outlets 9, 9' are each formed by congruent circular recesses in the support frames 10, 10'.

[0077] The anode-side support frame 10 has a manifold 8' with a module supply line 14, so that electrolysis medium can be directed into the anode compartment 6. In the cathode-side support frame 10', a first magnetic current sensor 12' (not shown) is arranged around the manifold 8'.

[0078] The cathode-side support frame 10' has a manifold 9' with a (not shown) module 15' for draining the electrolysis medium and the produced gas H2 from the cathode chamber 7. A second magnetic current sensor 13 is arranged around this manifold 9' in the anode-side support frame 10. 65208 / AG / VH

[0079] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)

[0080] In the support frames 10, 10', each common supply line 8, 8' has a module supply line 14, 14' leading to either the anode compartment 6 or the cathode compartment 7. Each common supply line 9, 9' has a module supply line 15, 15' leading from either the anode compartment 6 or the cathode compartment 7.

[0081] The first and second electrical current sensors 12, 12', 13, 13' are arranged in the support frame 10, 10' around those common supply lines 8, 8' and common supply lines 9, 9' which do not have a module supply line 14, 14' or module supply line 15, 15'.

[0082] In this embodiment, the module inlets 14, 14' and module outlets 15, 15' are designed as rectangular openings. However, they can also be round, for example in the form of bores.

[0083] The current sensors 12, 12', 13, 13' are designed for galvanically isolated, inductive measurement of the electric current flowing through the common leads 8, 8' and common leads 9, 9'. They may include an iron core surrounding the common leads 8, 8', 9, 9'. Furthermore, the current sensors 12, 12', 13, 13' may be provided with transmission elements for wireless or wired transmission of the measured values. The current sensors 12, 12', 13, 13' may also include a Hall effect sensor.

[0084] Fig. 2a shows a schematic cross-section of an electrolyzer with electrolysis modules 1 arranged in series according to Figs. 1a to 1d. Fig. 2a schematically shows the cross-section of the electrolyzer through section AA of an electrolysis module 1 from Fig. 1b.

[0085] Figure 2a schematically shows the supply lines 8 for lye into the cathode compartment 7 and the supply lines 9 for O2 from the anode compartment 6 in the electrolysis modules 1 arranged in series. The first and second magnetic current sensors 12, 13' are located in the individual electrolysis modules 1 as described above in Figure 2a. 65208 / AG / VH

[0086] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)

[0087] The electrolysis modules 1 are separated and arranged by end plates 5. Preferably, two electrolysis modules 1 are separated by a single end plate 5. A plurality of electrolysis modules 1, preferably between 50 and 200, can be connected in series. Figures 2a to 2c show fourteen electrolysis modules 1 connected in series by way of example. The value X shown in the figure as the number of electrolysis modules is 14 here, but X can be up to approximately 200.

[0088] During operation, stray currents can be measured by the magnetic current sensors 12, 12', 13, 13' arranged in the electrolysis modules 1. The electrolysis medium in this embodiment is KOH. However, NaOH can also be used.

[0089] The current distribution within an electrolyzer is typically configured as shown in the diagrams corresponding to the electrolyzer in Figures 2b and 2c. The x-axis represents the electrolysis modules 1, and the y-axis represents the current per unit area. By determining the stray currents, the efficiency of individual electrolysis modules 1 or of the entire electrolyzer can be determined. This is particularly important for an electrolyzer operating under partial load.

[0090] Fig. 2b shows the current distribution in the manifold inlet 8. Fig. 2c shows the current distribution in the manifold outlet 9. Due to the voltage between adjacent cells and the electrical conductivity of the electrolyte in the manifold inlets 8 and outlets 9, a parallel current path results. The local stray current in a manifold outlet or manifold inlet typically increases from one end of the electrolyzer towards the center because each electrolysis module 1 contributes a share of the total stray current, which accumulates towards the center.

[0091] The invention is not limited to the illustrated embodiment, but encompasses all electrolysis modules and electrolyzers according to any of the following claims. 65208 / AG / VH

[0092] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)

[0093] Reference symbol list

[0094] 1 electrolysis module

[0095] 2 Anode

[0096] 3 Cathode

[0097] 4 Separation layer

[0098] 5 End plate

[0099] 6 anode compartment

[0100] 7 Cathode space

[0101] 8, 8' Collective supply lines

[0102] 9, 9' Collective derivatives

[0103] 10, 10' support frame

[0104] 12, 12' First magnetic current sensors

[0105] 13, 13' Second magnetic current sensors

[0106] 14, 14' Module leads

[0107] 15, 15' module derivations

Claims

65208 / AG / VH Andritz AG, Stattegger Strasse 18, 8045 Graz (AT) Patent claims 1. Electrolysis module (1) for alkaline hydrogen electrolysis, comprising: - an anode (2), a cathode (3) and a substantially ion-permeable and electrically insulating separating layer (4) arranged between the anode (2) and the cathode (3), - two electrically insulating and essentially identical support frames (10, 10') connected to each other at their edges, wherein the anode (2) is connected to the first support frame (10) and the cathode (3) is connected to the second support frame (10'), forming an anode compartment (6) and a cathode compartment (7), wherein o in the anode-side support frame (10) and in the cathode-side support frame (10') each have two manifold inlets (8, 8') for supplying electrolysis medium and two manifold outlets (9, 9') each for draining electrolysis and product medium, and wherein o the support frames (10, 10') are arranged such that the manifold inlets (8, 8') and the manifold outlets (9, 9') of adjacent support frames (10, 10') are arranged essentially congruently, characterized in that in the support frames (10, 10') each of the collector leads (8, 8') a first magnetic current sensor (12, 12'),and each of the collector leads (9, 9') has a second magnetic current sensor (13, 13').

2. Electrolysis module (1) according to claim 1, characterized in that in the support frame (10, 10') each of the collector leads (8, 8') has a module lead (14, 14') into the anode compartment (6) or cathode compartment (7), and each of the collector leads (9, 9') has a module lead (15, 15') from the anode compartment (6) or cathode compartment (7), wherein the current sensors (12, 12', 13, 13') are arranged in a ring shape around those collector leads (8, 8') and collector leads (9, 9') that do not have a module lead (14, 14') or module lead (15, 15'). 65208 / AG / VH Andritz AG, Stattegger Strasse 18, 8045 Graz (AT) 3. Electrolysis module (1 ) according to claim 1 or 2, characterized in that the manifold inlets (8, 8') and manifold outlets (9, 9') are preferably circular recesses in the support frame (10, 10').

4. Electrolysis module (1 ) according to one of claims 1 to 3, characterized in that the support frames (10, 10') comprise or consist of plastic.

5. Electrolysis module (1 ) according to one of claims 1 to 4, characterized in that the current sensors (12, 12', 13, 13') are designed for galvanically isolated measurement of the electric current flowing through the collector leads (8, 8') and collector outlets (9, 9'), and wherein a transmission element is provided for wireless or wired transmission of the measured values.

6. Electrolysis module (1 ) according to one of claims 1 to 5, characterized in that an electrically conductive end plate (5) is arranged in a liquid-tight manner on one or both support frames (10, 10'), wherein the end plate (5) has recesses for the collector inlets (8, 8') and collector outlets (9, 9').

7. Electrolysis module (1 ) according to one of claims 1 to 6, characterized in that the electrolysis medium is a potassium hydroxide solution KOH or sodium hydroxide solution NaOH.

8. Electrolyzer comprising several electrolysis modules (1 ) according to one of claims 1 to 7, characterized in that the individual electrolysis modules (1 ) are arranged in series as an electrolysis stack such that the manifold inlets (8, 8') and manifold outlets (9, 9') run congruently through the entire electrolysis stack. 65208 / AG / VH Andritz AG, Stattegger Strasse 18, 8045 Graz (AT) 9. Electrolyzer according to claim 8, characterized in that the electrolysis modules (1 ) are under a pressure of over 10 bar, preferably about 30 bar.

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