Elektrolyser, use for an elektrolyser, supply pipe for an electrolyser and discharge pipe for an electrolyser

Abstract

The invention relates to an electrolyser (2) comprising a plurality of cell elements (4) and comprising a supply pipe (6) and a discharge pipe (8) for supplying and discharging an electrolyte to and from the cell elements (4), wherein, at least in sections, the supply pipe (6) and / or the discharge pipe (8) have at least two sub-lines (12a to 12t) that are galvanically isolated from one another, wherein the sub-lines (12a-12t) are designed an eccentric sub-lines (12a-12t).

Description

[0001] Description

[0002] Electrolyzer, insert for an electrolyzer, supply pipe for an electrolyzer and discharge pipe for an electrolyzer

[0003] The invention relates to an electrolyzer having a plurality of cell elements and having a supply pipe and a discharge pipe for supplying and discharging electrolyte to and from the cell elements. Furthermore, the invention relates to an insert for such an electrolyzer, a supply pipe for such an electrolyzer, and a discharge pipe for such an electrolyzer.

[0004] During electrolysis, redox reactions associated with material transformations can be forced by applying an electric current through suitable cell elements. A device for this purpose is called an electrolyzer and can be used to produce important basic materials in the chemical industry. The anode and cathode half-spaces are often separated by diaphragms (or membranes) which enable electrical conductivity (ion and / or proton exchange) but prevent material exchange. If liquid electrolytes are used in electrolyzers which are changed or consumed by the material transformation, these can be continuously renewed during the process by means of appropriate supply and discharge lines. The material transformation rates for given cell elements are generally subject to strict limits due to current density limitations.For large-scale use, the active cell element area must therefore be increased in order to increase the material conversion rates. This can be achieved by enlarging the cell elements or by operating a number of smaller cell elements at the same time. A technically sensible and frequently used method is to arrange many (identical) cell elements in a stack. The electrical connection of the cell elements in a stack is a series circuit, i.e. the anode of a cell element N is electrically connected to the cathode of cell element N+1 and the cathode of cell element N is electrically connected to the anode of cell element N1. The series connection also multiplies the low cell element voltage from a few volts to, for example, several hundred volts. The hydraulic connection of the cell elements in a stack to supply fresh electrolyte, on the other hand, is a parallel circuit.The hydraulic interconnection of the cell elements to form a stack creates additional and undesirable electrically conductive connections between all cell elements. During operation of the stack of cell elements, i.e., when an electrical voltage is applied or an electrical current is impressed from the first to the last cell element, an electrical working current flows through all cell elements. However, undesirable stray electrical currents also flow along the various parallel current paths. These stray electrical currents lead to local current density increases near the electrolyte supply and discharge lines, particularly at the first and last cell elements in a stack. This can lead to premature aging and destruction of the membranes and to the failure of the entire stack.

[0005] Stray electrical currents can be reduced by increasing the electrical resistance of the supply and discharge lines of the electrolytes. The current solution involves lengthening the supply and discharge lines, which results in an increase in resistance while maintaining the same cross-sectional area. However, these line extensions disadvantageously lead to increased flow resistance and increased material requirements for production.

[0006] There is therefore a need to demonstrate ways of remedying this situation. The object of the invention is achieved by an electrolyzer having a plurality of cell elements and having a supply pipe and a discharge pipe for supplying and discharging electrolyte to and from the cell elements. The supply pipe and / or the discharge pipe has, at least in sections, at least two galvanically isolated sub-conductors. The sub-conductors are designed as eccentric sub-conductors and are configured such that a current path extension of the current paths of stray electrical currents in the supply pipe and / or the discharge pipe is effected.

[0007] A supply pipe or discharge pipe is defined as an elongated hollow body whose length is significantly greater than its diameter. Unlike a hose, a pipe is made of a relatively inflexible material. For example, the supply pipe and the discharge pipe can be so rigid that manual deformation, as with a hose such as a corrugated hose, is impossible; instead, a tool is required.

[0008] In other words, by at least partially galvanically isolated sub-conductors, the majority of the cell elements forming a stack are divided into at least two cell element groups that are better electrically insulated from each other. This lengthens the current path for at least some of the stray electrical currents, which, due to the extension, result in a higher ohmic resistance, without lengthening the supply and / or discharge pipes, which in turn would result in increased flow losses.

[0009] The eccentric design of the sub-pipes enables a particularly stable structure with optimized utilization of the cross-sectional area of ​​the supply pipe or the discharge pipe. Eccentric refers to arrangements outside of a circle's center or pivot point, for example, where the sub-pipes are not arranged like concentric circles or rings.

[0010] According to one embodiment, at least one of the partial conduits is designed to form a honeycomb structure. Thus, the partial conduits, with their respective cross-sectional areas, form a regular pattern with the cross-sectional areas serving as cell elements. The respective cross-sectional areas can have any basic shape, e.g., triangular, square, or even circular. Such a honeycomb structure results in a particularly stable construction without the need for additional stabilizing elements.

[0011] According to a further embodiment, at least one of the partial lines has a hexagonal cross-sectional area.

[0012] Thus, the respective cross-sectional areas form a honeycomb structure, which is both particularly stable and provides maximized cross-sectional areas.

[0013] According to a further embodiment, the partial lines are each designed to provide an equal cross-sectional area. This ensures that each cell element group can be supplied with the same amount of electrolyte per unit of time. This enables a particularly simple structure, since each cell element group can have the same number of cell elements.

[0014] According to a further embodiment, the partial lines extend in the supply pipe with a predetermined length in the direction opposite to the electrolyte flow direction and / or in the discharge pipe with a predetermined length in the direction of the electrolyte flow direction. This allows the current path extension to be further increased. According to a further embodiment, at least one of the partial lines is formed by a passage extending through an insert in the supply pipe and / or discharge pipe. This allows the partial lines to be formed particularly easily by a one-piece and / or uniformly material component.

[0015] According to a further embodiment, at least one of the partial lines is formed by a groove extending parallel to the passage. In other words, while the other partial lines are completely enclosed by the insert, the partial line formed by the groove is only partially enclosed by the insert. Rather, the insert and the pipe casing of the supply pipe or discharge pipe together form a casing for this passage. This allows for the formation of a further partial line particularly easily.

[0016] According to a further embodiment, the insert comprises at least one pipe section and a ring element associated with each pipe section, wherein the respective ring element extends radially outward from the pipe section and terminates at least one partial line. For example, the insert can be formed in one piece and / or from a single material, thus allowing the formation of a plurality of partial lines by assembling only one component.

[0017] The invention further includes an insert for such an electrolyzer, a supply pipe and a discharge pipe for such an electrolyzer.

[0018] The invention will now be explained with reference to a drawing. It shows:

[0019] Figure 1 shows a schematic representation of the components of an electrolyzer. Figure 2 shows a schematic representation of an insert for the electrolyzer shown in Figure 1.

[0020] Figure 3 shows a schematic representation of further details of the insert shown in Figure 2.

[0021] Figure 4 shows a schematic representation of further details of the insert shown in Figure 2.

[0022] Figure 5 shows a schematic representation of further details of the insert shown in Figure 2.

[0023] Figure 6 shows a schematic representation of further details of the insert shown in Figure 2.

[0024] Figure 7 shows a schematic representation of a further representation of the electrolyzer shown in Figure 1 with an insert shown in Figures 2 to 7.

[0025] Reference is first made to Figure 1.

[0026] Shown is an electrolyzer 2.

[0027] In the present embodiment, the electrolyzer 2 comprises a plurality of cell elements 4 that form a stack 10 and are electrically connected in series. Furthermore, the electrolyzer 2 in the present embodiment comprises a supply pipe 6 and a discharge pipe 8, each with circular cross-sectional areas, through which electrolyte can first be supplied to the cell elements 4 and then discharged from the cell elements 4. For this purpose, both the supply pipe 6 and the discharge pipe 8 each have a plurality of outlet and inlet openings (not shown).

[0028] In order to effect a current path extension of the current paths of stray electrical currents, in the present exemplary embodiment an insert 14 is inserted in each of the supply pipe 6 and the discharge pipe 8.

[0029] The structure of an embodiment of the insert 14 will now be explained with additional reference to Figures 2 to 6.

[0030] In the present embodiment, the insert 14 has 19 pipe sections 16a to 16s, each forming a sub-line 12a to 12s. Deviating from the present embodiment, the number of pipe sections 16a to 16s may also be different.

[0031] Furthermore, in the present embodiment, each of the partial lines 12a to 12s has a hexagonal cross-sectional area and thus forms a honeycomb structure. In other words, in the present embodiment, the partial lines 12a to 12s are each formed by a passage 20a to 20s, which extend through the insert 14 along their main extension direction and, in the present embodiment, are each formed rectilinearly and parallel to one another.

[0032] The passages 20a to 20s or the webs connecting the passages 20a to 20s can form flow-optimized inlet areas by rounding them.

[0033] A homogenization of the electrolyte distribution can be achieved by optimized cross-sectional areas of the supply and discharge lines of the respective cell element of the stack 10 accompanied by an adjustment of the flow resistance, ie deviations from the uniform honeycomb structure and / or by optimized inlet surfaces.

[0034] Furthermore, the partial lines 12a to 12s are designed as eccentrically extending partial lines 12a to 12s, i.e., they are located outside a circle center or pivot point. In other words, in the present embodiment, the partial lines 12a to 12s are not arranged like concentric circles or rings.

[0035] In the present embodiment, one of the partial lines 12t is further formed by a groove 22 which extends parallel to the passages 20a to 20s and forms a further passage 20t.

[0036] The partial line 12t formed by the groove 22 is only partially encased by the insert 14. Rather, the insert 14 and the pipe casing of the supply pipe 6 or discharge pipe 8 together form a casing of this passage 20t.

[0037] Each of the sub-lines 12a to 12t ends at a ring element 18a to 18t, which seals the respective sub-line 12a to 12t from the supply line 6 or discharge line 8. Thus, each of the sub-lines 12a to 12t can supply a cell element group of the stack 10 with electrolyte or remove electrolyte. In the present embodiment, a first cell element group is supplied with electrolyte or removed from electrolyte in the electrolyte flow direction E through the sub-lines 12t formed by the groove 22.

[0038] In the present embodiment, the insert 14 is formed in one piece and / or from a single material. In particular, in the present embodiment, the insert 14—like the supply pipe 6 and the guide 8—is made of an electrically insulating material.

[0039] Reference is now made additionally to Figure 7.

[0040] It is shown that, when inserted into the supply pipe 6 or the discharge pipe 8, the respective ring element 18a to 18t comes into contact with the inner wall of the supply pipe 6 or the discharge pipe 8, thus providing a closure which, in the present embodiment, closes one of the partial lines 12a to 12t. Additional seals can be provided here for sealing. Small leaks of the insert 14 between adjacent cell element groups of the stack can be tolerated, resulting in a simple sealing concept.

[0041] In the present embodiment, the supply pipe 6 and the discharge pipe 8 are rigid in the section in which the respective inserts 14 are located and, in comparison, flexible in the remaining section.

[0042] In the present embodiment, the respective cross-sectional areas of the partial lines 12a to 12t are equal. This allows for a largely homogeneous electrolyte distribution across all cell element groups of the stack 10.

[0043] For example, a stack of 10 cells containing 20 cells is supplied with electrolyte.

[0044] Furthermore, in the present embodiment, the inserts 14 inserted into the supply pipe 6 and the discharge pipe 8 extend, in the case of the supply pipe 6, with a predetermined length L in the direction opposite to the electrolyte flow direction E, and, in the case of the discharge pipe 8, with the predetermined length L in the direction of the electrolyte flow direction E. In the present embodiment, the respective lengths L are equal. However, in contrast to the present embodiment, they can also be of different sizes.

[0045] In the present embodiment, the length L has a value in the range of 0.5 m to 3 m, e.g. 2 m.

[0046] Inserting the insert 14 separates the individual sections of the stack 10. This forces stray electrical currents exiting from the rear sections and entering the front sections onto extended current paths S. The extended current paths S are connected to an increased ohmic resistance, thus reducing the stray electrical current strengths. This allows a maximum stray electrical current density to be reduced by 70% (to 30%).

[0047] In other words, this provides an electrical series connection and a hydraulic parallel connection while maintaining a particularly compact design.

[0048] This achieves a current path extension for at least some of the stray electrical currents, resulting in a higher ohmic resistance due to the extension, without lengthening the supply pipe 6 and / or discharge pipe 8, which in turn would result in increased flow losses. At the same time, an insert 14 is provided that is easy to manufacture and, thanks to its honeycomb structure, is particularly stable.

Claims

Patent claims 1. Electrolyzer (2) , with a plurality of cell elements (4) , and with a supply tube (6) and a discharge tube (8) for supplying and discharging electrolyte to and away from the cell elements (4) , wherein the supply tube (6) and / or the discharge tube (8) has at least sectionally at least two galvanically isolated partial lines (12a to 12t) , wherein the partial lines (12a to 12t) are designed as eccentric partial lines (12a to 12t) and are arranged in such a way that a current path extension of the current paths of electrical stray currents in the supply tube (6) and / or the discharge tube (8) is caused.

2. Electrolyzer (2) according to claim 1, wherein at least one of the partial lines (12a to 12t) is configured to form a honeycomb structure.

3. Electrolyzer (2) according to claim 2, wherein at least one of the partial lines (12a to 12t) has a hexagonal cross-sectional area.

4. Electrolyzer (2) according to claim 1, 2 or 3, wherein the partial lines (12a to 12t) are each designed to provide an equal cross-sectional area.

5. Electrolyzer (2) according to one of claims 1 to 4, wherein the partial lines (12a to 12t) extend in the inlet pipe (6) with a predetermined length (L) in the direction opposite to the electrolyte flow direction (E) and / or extend in the outlet pipe (8) with a predetermined length (L) in the direction of the electrolyte flow direction (E).

6. Electrolyzer (2) according to one of claims 1 to 5, wherein at least one of the partial lines (12a to 12s) is formed by a passage (20a to 20s) which is defined by a Insertion (14) extends into the inlet pipe (6) and / or outlet pipe (8).

7. Electrolyzer (2) according to claim 6, wherein at least one of the partial lines (12t) is formed by a groove (22) which extends parallel to the passage (20a to 20s).

8. Electrolyzer (2) according to one of claims 1 to 4, wherein the insert has at least one pipe section (16a, to 16t) and a ring element (18a, to 18t) assigned to each pipe section (16a, to 16t), wherein the respective ring element (18a, to 18t) extends radially outwards from the respective pipe section (16a, to 16t) and terminates each partial line (12a to 12t).

9. Insert (14) for an electrolyzer (2) according to one of the Claims 1 to 8.

10. Supply pipe (6) for an electrolyzer (2) with a Use (14) according to claim 9.

11. Discharge pipe (8) for an electrolyzer (2) with a Use (14) according to claim 9.

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