Electrolyser, insert for electrolyser, feed line for electrolyser, and discharge line for electrolyser

Abstract

The invention relates to an electrolyzer (2) having a plurality of cell units (4) and having an inlet line (6) for supplying electrolyte to the cell units (4) and an outlet line (8) for discharging electrolyte from the cell units (4), the inlet line (6) and / or the outlet line (8) have, at least in some sections, at least two partial lines (12a to 12t) which are galvanically isolated from one another, the partial lines (12a to 12t) being designed as eccentrically extending partial lines (12a to 12t).

Description

Technical Field

[0001] The invention relates to an electrolyzer having a plurality of electrolytic cell units and having an inlet pipe for supplying electrolyte to the electrolytic cell units and an outlet pipe for discharging electrolyte from the electrolytic cell units. The invention also relates to an insert for such an electrolyzer, an inlet pipe for such an electrolyzer and an outlet pipe for such an electrolyzer. Background Art

[0002] In the electrolysis process, the redox reaction associated with the material conversion can be forced to occur by applying an electric current to flow through a suitable electrolyzer unit. The device for this purpose is called an electrolyzer, and can be used to produce important raw materials for the chemical industry. In many cases, the anode half space and the cathode half space are separated by a diaphragm (or membrane) that allows conduction (ion exchange and / or proton exchange) but prevents material exchange. If a liquid electrolyte that is changed or consumed due to material conversion is used in an electrolyzer, the liquid electrolyte can be continuously updated during the process by corresponding input and output pipelines. Due to the limitation of current density, for a given electrolyzer unit, the material conversion rate usually has a narrow limit. Therefore, in order to use on a large scale, the active electrolyzer unit area must be increased to improve the material conversion rate. This can be achieved by expanding the electrolyzer unit or by running multiple smaller electrolyzer units simultaneously. A technically meaningful and frequently used method is to arrange multiple (identical) electrolyzer units into an electrolytic stack. The electrical connection of the electrolytic cell units of the electrolytic stack is a series connection here, that is, the anode of electrolytic cell unit N is electrically conductively connected to the cathode of electrolytic cell unit N+1, and the cathode of electrolytic cell unit N is electrically conductively connected to the anode of electrolytic cell unit N-1. The series connection also multiplies the low electrolytic cell voltage from a few volts to, for example, several hundred volts. In contrast, the hydraulic interconnection of the electrolytic cell units of the electrolytic stack for supplying fresh electrolyte is a parallel connection. By hydraulically interconnecting the electrolytic cell units to form an electrolytic stack, an additional and undesirable conductive connection is generated between all electrolytic cell units. During the operation of the electrolytic stack of the electrolytic cell units, that is, during the application of voltage or the application of current from the first electrolytic cell unit to the last electrolytic cell unit, the operating current flows through all electrolytic cell units. However, undesirable so-called stray currents flow additionally on various parallel current paths. This stray current causes an excessive increase in the local current density near the input and output pipelines of the electrolyte, especially at the first and last electrolytic cell units of the electrolytic stack. This can lead to premature aging and destruction of the membranes and, in turn, failure of the entire electrolysis stack.

[0003] Reducing stray currents can be achieved by increasing the resistance of the electrolyte inlet and outlet lines. Previous solutions have proposed lengthening the inlet and outlet lines, thereby increasing the resistance while keeping the cross-sectional area the same. However, lengthening the lines disadvantageously leads to increased flow resistance and increased material requirements for production.

[0004] Therefore, it is necessary to point out a way to solve this problem. Summary of the invention

[0005] The object of the present invention is achieved by an electrolyzer, which has a plurality of electrolytic cell units and has an input pipe for supplying electrolyte to the electrolytic cell units and an output pipe for discharging electrolyte from the electrolytic cell units, wherein the input pipe and / or the output pipe have at least two sub-pipelines that are electrically isolated from each other at least in partial sections, wherein the sub-pipelines are constructed as eccentric sub-pipelines and are configured so that the current path of stray currents in the input pipe and / or the output pipe is extended.

[0006] In this context, an inlet or outlet pipe is understood to be an elongated hollow body whose length is substantially greater than its diameter. In contrast to a hose, the pipe is made of a relatively inflexible material. Thus, the inlet and outlet pipe can be designed to be rigid, so that it cannot be deformed by hand, as is the case with hoses such as corrugated hoses, but rather requires the use of tools.

[0007] In other words, the plurality of electrolytic cell units forming the electrolytic stack is divided into at least two electrolytic cell unit groups that are better electrically insulated from each other by at least two sub-pipelines that are configured to be electrically isolated from each other at least in sections. This allows for a current path extension for at least a portion of the stray currents, which increases the ohmic resistance without extending the inlet and / or outlet pipes, which would result in increased flow losses.

[0008] By configuring the sub-pipes as eccentrically extending sub-pipes, a particularly stable construction can be achieved which optimally utilizes the cross section of the inlet or outlet pipe. The term "eccentric" is understood here to mean that the sub-pipes are arranged outside the center of a circle, more precisely the center of an axis, i.e., not like concentric circles or concentric rings relative to one another.

[0009] According to one embodiment, at least one of the sub-pipelines forms an array-like structure. As a result, the sub-pipelines with their respective cross sections form a regular pattern, which has a cross-sectional area corresponding to the electrolytic cell unit. The individual cross sections can have any basic shape, for example, be configured as a triangle, a quadrilateral or even a circle. This array-like structure makes the structure particularly stable without additional stabilizing elements.

[0010] According to another embodiment, at least one of the partial pipes has a hexagonal cross section, whereby the cross sections form a honeycomb structure which is particularly stable and provides a maximized cross section.

[0011] According to another embodiment, the sub-pipes are provided with the same cross-section, thereby ensuring that the same amount of electrolyte can be supplied to each electrolytic cell unit group per unit time. Since each electrolytic cell unit group can have the same number of electrolytic cell units, the structure can be made particularly simple.

[0012] According to another embodiment, the sub-pipeline extends in a predetermined length in the direction opposite to the electrolyte flow direction in the input pipe and / or extends in a predetermined length in the electrolyte flow direction in the output pipe. Thus, the current path can be further extended.

[0013] According to another embodiment, at least one of the sub-pipelines is formed by a channel, which extends through an insert in the inlet and / or outlet pipe. Thus, the sub-pipeline can be particularly conveniently formed by an integral and / or one-piece component in terms of material.

[0014] According to another embodiment, at least one of the sub-pipelines is formed by a groove, which extends parallel to the channel. In other words, while the other sub-pipelines are completely enveloped by the insert, the sub-pipeline formed by the groove is only partially enveloped by the insert. More precisely, the insert and the pipe jacket of the inlet or outlet pipe together form the envelope of the channel. In this way, the other sub-pipeline can be formed particularly easily.

[0015] According to another embodiment, the insert has at least one pipeline segment and an annular element associated with each pipeline segment, wherein the respective annular element extends radially outward from the pipeline segment and respectively terminates the sub-pipeline. For example, the insert can be integrally formed and / or in one piece in terms of material and thus make it possible to form a plurality of sub-pipelines by assembling only one component.

[0016] Furthermore, an insert for such an electrolyser, supply lines and discharge lines for such an electrolyser also belong to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will now be explained with reference to the accompanying drawings, in which:

[0018] Figure 1 The components of an electrolyser are shown schematically.

[0019] Figure 2 The schematic diagram shows the Figure 1 Inserts for an electrolyser are shown.

[0020] Figure 3 The schematic diagram shows Figure 2 Further details of the insert are shown.

[0021] Figure 4 The schematic diagram shows Figure 2 Further details of the insert are shown.

[0022] Figure 5 The schematic diagram shows Figure 2 Further details of the insert are shown.

[0023] Figure 6 The schematic diagram shows Figure 2 Further details of the insert are shown.

[0024] Figure 7 The schematic diagram shows Figure 1 Another illustration of an electrolyzer shown, the electrolyzer having Figures 2 to 7 Insert shown. DETAILED DESCRIPTION

[0025] First refer to Figure 1 .

[0026] An electrolyser 2 is shown.

[0027] In the present embodiment, the electrolyzer 2 has a plurality of electrolytic cell units 4 which form an electrolytic stack 10 and are electrically connected in series. In addition, in the present embodiment, the electrolyzer 2 also has an input pipe 6 and an output pipe 8, each having a circular cross section, with which the electrolyte can first be supplied to the electrolytic cell unit 4 and then discharged from the electrolytic cell unit 4. For this purpose, the input pipe 6 and the output pipe 8 each have a plurality of outlet openings and inlet openings (not shown).

[0028] In order to extend the current path of the stray current, in the present embodiment, an insert 14 is respectively inserted into the inlet pipe 6 and the outlet pipe 8 .

[0029] Now by additionally referring to Figures 2 to 6 The structure of an exemplary embodiment of the insert 14 will be explained.

[0030] In the present embodiment, the insert 14 has 19 pipeline sections 16a to 16s, which respectively form the partial lines 12a to 12s. The number of pipeline sections 16a to 16s may also be different from that in the present embodiment.

[0031] In addition, in the present embodiment, each sub-pipeline 12a to 12s has a hexagonal cross section, and thus forms an array structure or a honeycomb structure. In other words, in the present embodiment, the sub-pipelines 12a to 12s are respectively formed by channels 20a to 20s, which extend through the insert 14 along the main extension direction of the insert 14, and in the present embodiment, are respectively configured to be straight and parallel to each other.

[0032] The channels 20 a to 20 s , or more precisely the connecting webs connecting the channels 20 a to 20 s , can form a flow-optimized inlet region by rounding.

[0033] A homogenization of the electrolyte distribution can be achieved by optimized cross sections of the feed and discharge lines of the respective electrolysis cell units of the electrolysis stack 10 , together with an adjustment of the flow resistance (ie a deviation from a regular matrix-like structure) and / or by optimized inlet surfaces.

[0034] In addition, the sub-pipes 12a to 12s are configured as eccentrically extending sub-pipes 12a to 12s, ie they are located outside the center of the circle, more precisely the axis. In other words, in this embodiment, the sub-pipes 12a to 12s are not arranged relative to each other like concentric circles or concentric rings.

[0035] In the present embodiment, one of the sub-pipes 12t is also formed by a groove 22 which extends parallel to the channels 20a to 20s and forms another channel 20t.

[0036] The partial pipeline 12t formed by the groove 22 is only partially enveloped by the insert 14. More precisely, the insert 14 and the pipe jacket of the supply line 6 or the discharge line 8 together form the envelope of the channel 20t.

[0037] Each sub-pipeline 12a to 12t ends at an annular element 18a to 18t, which seals the corresponding sub-pipeline 12a to 12t relative to the input pipe 6 or the output pipe 8. Thus, each of the sub-pipelines 12a to 12t can be used to supply electrolyte or drain electrolyte to the electrolytic cell unit group of the electrolytic stack 10. In the present embodiment, the first electrolytic cell unit group is supplied with electrolyte or drained electrolyte along the electrolyte flow direction E through the sub-pipeline 12t formed by the groove 22.

[0038] In the present embodiment, the insert 14 is integrally formed and / or is formed in one piece in terms of material. In particular, in the present embodiment, the insert 14 as well as the inlet line 6 and the outlet line 8 are made of electrically insulating material.

[0039] Now additionally refer to Figure 7 .

[0040] It is shown that in the inserted state of the inlet pipe 6 or the outlet pipe 8, the corresponding annular elements 18a to 18t are in contact with the inner wall of the inlet pipe 6 or the outlet pipe 8 and thus provide a seal which in the present embodiment closes one of the partial pipes 12a to 12t, wherein in this case a seal can additionally be provided for sealing. Small leaks of the insert 14 between adjacent electrolytic cell groups of the electrolysis stack can be tolerated, which results in a simple sealing concept.

[0041] In the present exemplary embodiment, the supply line 6 and the discharge line 8 are rigid in the section in which the respective insert 14 is located and are flexible in comparison in the remaining sections.

[0042] In this embodiment, the cross-sections of the sub-pipelines 12a to 12t are of the same size. Therefore, it is possible to distribute the electrolyte substantially evenly to all electrolytic cell unit groups of the electrolytic stack 10.

[0043] For example, electrolyte is thus supplied to an electrolysis stack 10 having 20 electrolysis cell units.

[0044] Furthermore, in the present embodiment, the inserts 14 respectively inserted into the inlet pipe 6 and the outlet pipe 8 extend by a predetermined length L in the direction opposite to the electrolyte flow direction E in the case of the inlet pipe 6, and extend by a predetermined length L in the case of the outlet pipe 8 along the electrolyte flow direction E. In the present embodiment, the respective lengths L have the same size. However, the respective lengths L may also have different sizes different from the present embodiment.

[0045] In this embodiment, the length L is in the range of 0.5 m to 3 m, for example, 2 m.

[0046] The insertion of the insert 14 separates the individual sections of the electrolytic stack 10. As a result, the stray currents that emerge from the rear section and enter the front section are forced to flow along an extended current path. This extended current path S is associated with an increased ohmic resistance, which reduces the intensity of the stray currents. As a result, the maximum value of the stray current density can be reduced by 70% (to 30%).

[0047] In other words, an electrical series connection and simultaneously a hydraulic parallel connection are thereby provided and at the same time the design is particularly compact.

[0048] This results in a lengthening of the current path for at least some of the stray currents, which results in a higher ohmic resistance without lengthening the inlet and / or outlet lines 6 and 8, which would lead to increased flow losses. At the same time, an insert 14 is provided which is easy to manufacture and is particularly stable due to the array-like structure.

Claims

1. An electrolyzer (2), comprising a plurality of electrolytic cell units (4), and comprising an inlet pipe (6) for supplying electrolyte to the electrolytic cell units (4) and an outlet pipe (8) for discharging electrolyte from the electrolytic cell units (4), wherein: The inlet pipe (6) and / or the outlet pipe (8) has at least two sub-pipes (12a to 12t) which are electrically isolated from each other at least in a partial section, wherein the sub-pipes (12a to 12t) are constructed as eccentric sub-pipes (12a to 12t) and are configured so that the current path of stray currents in the inlet pipe (6) and / or the outlet pipe (8) is extended.

2. The electrolyser (2) according to claim 1, wherein: At least one of the sub-pipelines (12a to 12t) forms an array-like structure.

3. The electrolyser (2) according to claim 2, wherein: At least one of the sub-pipelines (12a to 12t) has a hexagonal cross section.

4. The electrolyser (2) according to claim 1, 2 or 3, wherein: The sub-pipelines ( 12 a to 12 t ) respectively provide the same cross section.

5. The electrolyser (2) according to any one of claims 1 to 4, wherein: The sub-pipelines (12a to 12t) extend in the input pipe (6) in a direction opposite to the electrolyte flow direction (E) by a predetermined length (L), and / or extend in the output pipe (8) in the electrolyte flow direction (E) by a predetermined length (L).

6. The electrolyser (2) according to any one of claims 1 to 5, wherein: At least one of the partial lines (12a to 12s) is formed by a channel (20a to 20s) which extends through an insertion part (14) in the supply line (6) and / or the discharge line (8).

7. The electrolyser (2) according to claim 6, wherein: At least one of the sub-pipes (12t) is formed by a groove (22) which extends parallel to the channels (20a to 20s).

8. The electrolyser (2) according to any one of claims 1 to 4, wherein: The insert has at least one pipeline section (16a to 16t) and an annular element (18a to 18t) associated with each pipeline section (16a to 16t), wherein the respective annular element (18a to 18t) extends radially outward from the respective pipeline section (16a to 16t) and respectively terminates a sub-pipeline (12a to 12t).

9. An insert (14) for an electrolyser (2) according to any one of claims 1 to 8.

10. A supply line (6) for an electrolyser (2) having an insert (14) according to claim 9.

11. An outlet line (8) for an electrolyser (2) having an insert (14) according to claim 9.

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