Electrolytic cell with arched support member

Abstract

An electrolytic cell (1) for the electrolysis of chlor-alkali or alkaline water, comprising: two cell elements (2, 3), each cell element (2, 3) defining an electrode chamber (4, 5) by providing a rear wall (6) and side walls (7) of the electrode chamber (4, 5); electrodes (8, 9) respectively housed in each of the electrode chambers (4, 5); a sheet-like diaphragm (10) that extends in the height direction (H) and the width direction (W) of the electrolytic cell (1), is provided in a joint (11) between the two electrolytic cell elements (2, 3), and forms a partition wall (12) between the electrode chambers (4, 5); a plurality of support members (13) for supporting at least one electrode (8, 9) on a respective rear wall (6); wherein each support member (13) comprises: two support parts standing on the rear wall (6) and extending in the height direction (H) of the electrolytic cell (1); two feet (16, 17) connected to the respective supports (14, 15) at an angle and in planar contact with the rear wall (6); wherein the support portions of the support members (13) are connected to each other by means of an arch-shaped portion (18) bent outward toward the electrode (8) to be supported, and form an elastic bearing surface (19) for supporting the electrode (8); when the arch (18) deflects inwards, the bearing surface (19) increases.

Description

Background Art

[0001] The invention relates to an electrolytic cell according to the preamble of claim 1.

[0002] Electrolyzers for chlor-alkali and / or alkaline water electrolysis usually include two electrode chambers, each containing an electrode. The electrode chambers are separated by a sheet-like diaphragm. In each electrode chamber, the electrode is fixed to the rear wall of the electrode chamber by a supporting structure.

[0003] In the past, in order to prevent damage to the diaphragm during assembly and to allow product gases to escape freely on the diaphragm side of the electrode, the electrodes were typically mounted with a gap to the diaphragm (a "limited gap configuration"). However, to improve the efficiency of electrolyzers, so-called "zero gap configurations" have been developed, in which the electrodes are in close contact with the diaphragm on both sides. In order to reduce the risk of damaging the diaphragm during assembly and to provide uniform contact pressure, the support structure of at least one electrode in a zero gap design electrolyzer typically includes at least one resilient member.

[0004] In the prior art, zero-gap electrolyzers having elastic electrode support elements of different designs are known.

[0005] WO 2017 / 217427 A1 describes an electrolyzer comprising an elastic element arranged in a cathode chamber. The elastic element consists of a joint, a plurality of spring retaining portions and two spring rows on each spring retaining portion. The joint is attached to a flat electrolysis partition, and the spring row contacts the cathode. Each spring row consists of a plurality of first flat spring-shaped bodies. Similar elastic elements with flexible tongues for supporting electrodes can be found in EP 1 865 092 A2, EP 1900 851A2 and EP1 378 589 A1.

[0006] However, the flexible tongue of the existing elastic element has certain limitations in terms of the maximum surface pressure it can exert on the diaphragm. If the maximum pressure is exceeded, the flexible tongue will deform at its root, resulting in uneven surface pressure distribution. In addition, the protruding tongue may be entangled with the mesh material of the electrode, so that the tongue is deformed when the electrolyzer is opened for maintenance and / or electrode recoating. Therefore, during maintenance, the flexible tongue needs to be tediously repaired before the electrolyzer can be reassembled.

[0007] Another elastic support element in an electrolytic cell is disclosed in US 2021 / 222 306 A1, wherein the elastic support element comprises annular elements whose axes are arranged in the height direction of the electrolytic cell. During the assembly of the electrolytic cell, these annular elements are at least partially plastically deformed, and therefore also need to be repaired during maintenance. In addition, the elastic support element is at least welded to the electrode or the rear wall, which leads to high assembly and maintenance costs. Summary of the invention

[0008] An object of the present invention is to provide an electrolytic cell having an elastic support member to facilitate assembly of electrodes and reduce the amount of repair work during manufacturing and maintenance.

[0009] This object is achieved by an electrolysis cell having the features of claim 1 .

[0010] The present invention provides an electrolyzer for chlor-alkali or alkaline water electrolysis. The electrolyzer comprises two trough elements, each of which defines an electrode chamber by providing a rear wall and a side wall of the electrode chamber. In addition, the electrolyzer also comprises an electrode housed in each electrode chamber, and a sheet-like diaphragm extending in the height direction and the width direction of the electrolyzer. The diaphragm is arranged at the junction between the two electrolyzer elements and forms a partition wall between the electrode chambers. In addition, the electrolyzer also comprises a plurality of support members, which are used to support at least one electrode on the corresponding rear wall. Each support member comprises two support portions, which stand upright on the rear wall and extend in the height direction of the electrolyzer, and two feet, which are connected to the respective support portions in an angled manner so as to form a planar contact with the rear wall. According to the present invention, the support portions of the support members are connected to each other by an arched portion, which arches outwardly toward the supported electrode and forms an elastic bearing surface to support the electrode, wherein the bearing surface expands when the arched portion deflects inwardly.

[0011] The support member of the present invention forms an arched spring. The support member adopts a single-piece structure, and provides a static support component through the upright support part and an elastic support component through the deflectable arched part. The support member has the functions of support, current distribution and uniform contact pressure of the electrode at the same time.

[0012] Furthermore, since the bearing surface of the electrode increases when the arched portion deflects inwardly, this has a favorable effect on both the supported electrode and the supporting member.

[0013] During assembly of the cell, for example when contact pressure is applied at the joints of the cell elements, the load acting between the electrode and the respective rear wall is dispersed via the increased load bearing surface. The pressure is thus distributed over a larger electrode surface area, which improves the uniformity of the contact pressure between the electrode and the diaphragm.

[0014] On the other hand, due to the increase in the bearing surface, the arched portion of the support member exhibits a progressive spring characteristic. The progressive spring characteristic of the arched portion can reduce further deflection when the load increases, thereby reliably preventing the support member from plastic deformation. Therefore, during maintenance, the amount of repair work on the support member is reduced.

[0015] In a preferred embodiment, the foot is fixed to the rear wall by a detachable mechanical connection. If the foot is fixed to the rear wall by a detachable mechanical connection, the support member can be installed and replaced individually.

[0016] Preferably, the feet are separated by recesses into snaps which couple with slots provided in the rear wall. More preferably, the support member is fixed in the mounting position by a form-locking fit between the snaps and the slots. For example, the elastic properties of the support member can be used to deflect the feet during assembly so that the snaps of the two feet couple with the slots in the rear wall respectively, so as to achieve the mounting position. The slots are preferably formed in the rear wall by corrugated metal strips, which can be intermittently fixed to the rear wall, for example, by spot welding.

[0017] In a further preferred embodiment, the notch extends to the respective support portion so that a single clip can be suspended laterally. By extending the notch to the support portion, the clips can be deflected individually in the lateral direction. Thus, the mounting of the support member in the electrolytic cell is simplified, so that the clips can be inserted into the slots one by one.

[0018] Preferably, the elastic bearing surface is provided with an opening to discharge the gas generated on the supported electrode. Therefore, the gas generated by the electrode not only needs to escape through the mesh structure of the electrode, but also can enter the electrode chamber part behind the support member, which is filled with electrolyte during the operation of the electrolyzer. In addition, the opening can also improve the supply of fresh electrolyte to the electrode. Both effects contribute to improving the efficiency of the electrolyzer. However, if the opening is too large, the stability of the support member and the mechanical strength of the arched portion will be weakened. The opening ratio (defined as the ratio of the opening area to the entire bearing surface area) is preferably selected in the range of 0.6 to 0.85, more preferably in the range of 0.7 to 0.8.

[0019] In a preferred embodiment, the opening has an edge portion bent away from the supported electrode. The bent edge portion increases the geometric moment of inertia of the arched portion. Therefore, the bent edge portion allows the opening area to be increased while enhancing the supporting effect of the arched portion.

[0020] In some embodiments, the feet of adjacent support members are arranged side by side on the rear wall, which increases the contact area of ​​the support members on the rear wall, thereby improving the current distribution performance of the support members.

[0021] In other alternative embodiments, the feet of adjacent support members are arranged on the rear wall superimposed on each other.

[0022] In some preferred embodiments, the bearing surface is extended beyond the support portion in at least one side in the lateral direction by the extension portion of the support member. Therefore, the extension portion extends the arched portion on the side of the support portion away from the arched portion. Such an extension portion can be used to reduce or even completely eliminate the gap between the bearing surfaces of adjacent support members.

[0023] Preferably, the arched portion has an arch height and the support portion has a support height, wherein in the undeflected state of the arched portion, the ratio of the arch height to the support height is in the range of 1:3 to 1:30, more preferably in the range of 1:10 to 1:20. Therefore, most of the space between the rear wall and the electrode is preferably bridged by the support portion, while the arched portion is relatively flat. Such a cross-sectional structure of the support member is more ideal because it provides a wider bearing surface, thereby optimizing the elastic support of the electrode and uniform current distribution.

[0024] Further advantages of the present invention will be described below in conjunction with the embodiments shown in the accompanying drawings.

[0025] BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 schematically shows a cross-sectional view of an electrolytic cell according to the invention;

[0027] Figure 2A Schematically shows Figure 1 a first perspective view of a right side electrolytic cell element with a plurality of support members mounted on a rear wall;

[0028] Figure 2B Schematically shows Figure 2A a second enlarged perspective view of an electrolytic cell element;

[0029] Figure 3 Schematically shows the Figure 1 , Figure 2A and Figure 2B A perspective view of a single support member of the illustrated embodiment;

[0030] Figure 4A and 4B Schematically shows the Figure 3 A cross-sectional view of the support element shown in an unloaded state and in a loaded state;

[0031] Figures 5A to 5E Schematically showing in cross-sectional view different support member configurations according to the invention and their arrangement on the rear wall of the electrolytic cell;

[0032] Figure 6 schematically shows a perspective view of a support member in another embodiment;

[0033] Figure 7 Schematically shows Figure 6 A cross-sectional view of the support member shown.

[0034] DETAILED DESCRIPTION OF THE INVENTION

[0035] In the drawings, identical components are always identified with the same reference numerals and are therefore generally described and referred to only once.

[0036] Figure 1 A cross-sectional view of an electrolysis cell 1 for chlor-alkali or alkaline water electrolysis according to the invention is shown. The electrolysis cell 1 comprises two cell elements 2, 3, each defining an electrode chamber 4, 5 by providing a rear wall 6 and side walls 7 of the electrode chamber 4, 5, and each electrode chamber 4, 5 accommodates one electrode 8, 9.

[0037] Figure 2A , Figure 2B and Figure 3 A perspective diagram showing the Figure 1 The internal structure of the electrolytic cell 1 is described in more detail below. Figures 1 to 3 The structure of the electrolytic cell 1 will be described in detail.

[0038] The electrolytic cell 1 further comprises a sheet-like diaphragm 10 extending in the height direction H and the width direction W of the electrolytic cell 1. The diaphragm 10 is located at the joint 11 between the two cell elements 2, 3 and provides a partition wall 12 between the electrode chambers 4, 5. In the electrolytic cell 1, a plurality of support members 13 are provided, which support one of the electrodes 8 on the respective rear wall 6. Each support member 13 comprises two support portions 14, 15 which stand upright on the rear wall 6 and extend in the height direction H of the electrolytic cell 1, and two feet 16, 17 which are connected to the respective support portions 14, 15 in an angled manner so as to form a planar contact with the rear wall 6. According to the present invention, the support portions 14, 15 of the support member 13 are connected to each other by an arched portion 18. The arched portion 18 arches outwardly toward the supported electrode 8 and provides an elastic bearing surface 19 for the supported electrode 8. When the arched portion 18 deflects inwardly, the bearing surface 19 expands.

[0039] During operation, one of the electrodes 8, 9 acts as an anode and the other as a cathode of the electrolyzer. Due to the different chemical products obtained at the anode (chlorine, oxygen) and cathode (hydrogen), the electrode chambers 4, 5 can be designed differently. In particular, in chlor-alkali and alkaline water electrolysis, the conditions in the anode chamber are usually more severe due to the oxidation of the generated chlorine or oxygen. The elastic support member according to the present invention can be used in the anode chamber and / or the cathode chamber.

[0040] like Figure 2A and 2BAs shown, the feet 16, 17 can be fixed to the rear wall 6 by a detachable mechanical connection. In particular, the feet 16, 17 can be separated into snap-fits 21 by a notch 20 (see Figure 3 ), which couple with slots 22 provided on the rear wall 6. The slots 22 may be provided on the rear wall 6 by corrugated metal strips 23, which are intermittently fixed to the rear wall 6 by spot welding.

[0041] The structure of the support member 13 is Figure 3 The support parts 14, 15 together with the arched part 18 and the rear wall 6 form a hollow channel in the height direction H of the electrolytic cell so that the electrolyte and / or the gas generated on the supported electrode 8 can pass through unimpeded. Along the height direction H, the support member 13 can be divided into a plurality of separate arched structures 27, for example Figure 3 The seven arch structures 27 shown in FIG. These individual arch structures are preferably formed by extending the recesses 20 into the respective support parts 14, 15 and resulting in the lateral suspension of the buckles 21 of the feet 16, 17 forming the individual arch structures 27. Figure 3 As shown, the individual arches 27 can be connected to one another in the region of the supports 14, 15 by bridges 28. Alternatively, the recess can extend all the way to the arch 18, so that the individual arches 27 are connected to one another only in the region of the arch 18.

[0042] Preferably, the elastic bearing surface 19 includes an opening 24 for passing the gas generated on the supported electrode 8. Figure 3 As shown, the opening 24 may be a slit-like opening, preferably extending in the width direction W of the electrolytic cell 1. Preferably, a plurality of openings 24 are provided in each individual arch structure 27.

[0043] The opening ratio of the opening 24 to the entire bearing surface 19 (including the opening 24) may be in the range of 0.2 to 0.45, more specifically in the range of 0.25 to 0.35. Figure 3 As shown, the opening 24 is preferably provided with a curved edge portion 25 away from the supported electrode 8 .

[0044] The support portions 16, 17 may include cutouts 29. The cutouts 29 allow for better flow of electrolyte in the width direction W of the electrolytic cell 1 and reduce the amount of material required to manufacture the support member 13.

[0045] The support member 13 is preferably made of a metal material, particularly preferably nickel or titanium.

[0046] exist Figure 4AIn the embodiment, the support member 13 is in an undeflected, unloaded state. The arch 18 has an arch height h1, and the support portions 14, 15 have a support height h2. In the undeflected state, the ratio of the arch height h1 to the support height h2 is in the range of 1:3 to 1:30, in particular in the range of 1:3 to 1:6. The total height of the support member is denoted as h3.

[0047] If the electrode is placed on the arch 18 in an unloaded, undeflected state, the elastic bearing surface 19 is concentrated at the highest part of the arch structure and has an unloaded support width w1. Figure 4B In the embodiment, the support member 13 is in a loaded state. When the arch 18 deflects inwardly due to the load, the bearing surface 19 increases, resulting in an increase in the support width w2 under load. The support width w2 under load is preferably at least 50%, more preferably at least 75%, of the total width w3 of the arch 18. The support width w2 under load may reach 100% of the total width w3 of the arch 18.

[0048] Figures 5A to 5E Five different variants of arranging a plurality of adjacent support members 13 on the rear wall 6 of the electrolysis cell according to the invention are shown in cross-sectional views.

[0049] Figure 5A A support member 13 is shown with outwardly bent foot portions 16, 17. The feet 16, 17 are inserted from both sides in a side-by-side manner into slots formed under the metal strip 23. This arrangement provides a larger contact area with the rear wall 6, but at the same time results in a larger unsupported gap 30 between the arches 18 of adjacent support members 13.

[0050] In order to reduce the gap 30, it is possible to use Figure 5B The configuration shown, in which the feet 17, 16 of adjacent support members 13 are arranged one above the other on the rear wall 6. As a result, the width of the metal strip 23 and the width of the gap 30 are reduced.

[0051] Figure 5C An alternative arrangement is shown. If the feet 16, 17 are bent to the same side, the gap 30 between the arches 18 of adjacent support members 13 can be reduced to the width of one foot 16, 17. The feet 16, 17 are inserted into the slots below the metal strip 23 from one side. Figure 5C In the configuration shown, both or only one of the feet 16 , 17 can be fastened to the rear wall 6 .

[0052] Figure 5D A configuration with a minimum gap 30 is shown. The feet 16, 17 are bent inwardly so that the support parts 14, 15 of adjacent support members 13 are closely adjacent to each other. Although this configuration reduces the gap, the assembly work is greater because twice the number of metal strips 23 needs to be used.

[0053] at last, Figure 5E In the illustrated configuration, the bearing surface 19 extends laterally beyond the support portions 14, 15 by means of an extension 26 of the support member 13. In this way, the extension 26 can be used to support electrodes within the gap 30 between adjacent support members 13.

[0054] Figure 6 and Figure 7 Another embodiment of the support member 13 according to the present invention is shown. Figure 3 The embodiments are different. Figure 6 The bearing surface 19 in the embodiment of the present invention is configured as a regular grid, rather than being divided into a plurality of individual arches. As a result, the openings 24 are arranged at regular intervals over the entire bearing surface 19. This has the positive effect that the gas discharge and electrolyte exchange through the openings 24 of the bearing surface 19 are homogenized over the entire electrode 8. In addition, the regular structure homogenizes the surface pressure on the bearing surface 19.

[0055] and Figure 3 Compared with the embodiment of the present invention, another difference is that the opening ratio of the opening 24 to the entire supporting surface 19 is larger, that is, in the range of 0.6 to 0.85, and in particular in the range of 0.7 to 0.8. This larger opening ratio also enhances the electrolyte and gas exchange through the supporting surface 19 while still providing sufficient support for the electrode 8.

[0056] Figure 6 and Figure 7 Another feature of the embodiment of the invention is that the arch 18 is particularly flat. The ratio of the arch height h1 to the support height h2 (see Figure 7 ) is in the range of 1:3 to 1:30, and in particular in the range of 1:10 to 1:20 in the undeflected state of the arched portion 18. It has been found that a relatively flat arched portion 18 helps to provide a uniform surface pressure in the width direction W of the support element.

[0057] In all other respects, Figure 1 The description of the embodiment shown in FIG. 4 also applies to Figure 6 and Figure 7 The embodiment shown.

[0058] List of reference numerals:

[0059] 1 Electrolyzer

[0060] 2,3 slot components

[0061] 4,5 Electrode chamber

[0062] 6 Back wall

[0063] 7 Sidewall

[0064] 8,9 electrodes

[0065] 10 Sheet diaphragm

[0066] 11 Joint

[0067] 12 Divider Wall

[0068] 13 Supporting members

[0069] 14,15 support part

[0070] 16,17 feet

[0071] 18 Arch

[0072] 19 Elastic bearing surface

[0073] 20 Notch

[0074] 21 Buckle

[0075] 22 slots

[0076] 23 Metal Strip

[0077] 24 Opening

[0078] 25 Edge

[0079] 26 Extension

[0080] 27 Arched Structure

[0081] 28 Bridge

[0082] 29 Incision

[0083] 30 Gap

[0084] H Height direction

[0085] h1 Arch height

[0086] h2 support height

[0087] h3 Overall height of the supporting member

[0088] W Width direction

[0089] w1 Support width without load

[0090] w2 Support width under load

[0091] w3 Arch width.

Claims

1. An electrolytic cell (1) for chlor-alkali or alkaline water electrolysis, comprising: two trough elements (2, 3), each trough element (2, 3) defining an electrode chamber (4, 5) by providing a rear wall (6) and side walls (7) of the electrode chamber (4, 5); Electrodes (8, 9), respectively housed in each electrode chamber (4, 5); a sheet-like diaphragm (10) extending in the height direction (H) and the width direction (W) of the electrolytic cell (1), the diaphragm (10) being arranged in the joint (11) between two electrolytic cell elements (2, 3) and forming a partition wall (12) between the electrode chambers (4, 5); A plurality of support members (13) for supporting at least one (8) electrode (8, 9) on a corresponding rear wall (6); wherein each support member (13) comprises: Two support parts (14, 15) are erected on the rear wall (6) and extend along the height direction (H) of the electrolytic cell (1); Two feet (16, 17) connected to the corresponding support parts (14, 15) in a certain angle and forming a planar contact with the rear wall (6); Features: The supporting parts (14, 15) of the supporting member (13) are connected to each other through an arched part (18) bent outwardly toward the supported electrode (8), and form an elastic bearing surface (19) for supporting the electrode (8); when the arched part (18) deflects inwardly, the bearing surface (19) increases.

2. The electrolytic cell according to claim 1, characterized in that The feet (16, 17) are fixed to the rear wall (6) by a detachable mechanical connection.

3. The electrolytic cell according to claim 1 or 2, characterized in that: The feet (16, 17) are separated into buckles (21) by a notch (20), and the buckles (21) are buckled into slots (22) arranged on the rear wall (6).

4. The electrolytic cell according to claim 3, characterized in that The slots (22) are formed by corrugated metal strips (23) which are intermittently fixed to the rear wall (6) by spot welding.

5. The electrolytic cell according to claim 3 or 4, characterized in that: The notches (20) extend into the respective supports (14, 15) so as to allow the individual clips (21) to be suspended in the transverse direction.

6. The electrolytic cell according to any one of claims 1 to 5, characterized in that: The elastic bearing surface (19) comprises an opening (24) for discharging gas generated on the supported electrode (8).

7. The electrolytic cell according to claim 6, characterized in that The opening ratio of the opening (24) to the entire bearing surface (19) is in the range of 0.6 to 0.

85.

8. The electrolytic cell according to claim 7, characterized in that The opening ratio of the opening (24) to the entire bearing surface (19) is in the range of 0.7 to 0.

8.

9. The electrolytic cell according to any one of claims 6 to 8, characterized in that: The opening (24) is provided with a bent edge portion (25), and the edge portion (25) is bent in a direction away from the supported electrode (8).

10. The electrolytic cell according to any one of claims 1 to 9, characterized in that: The feet (16, 17) of adjacent support members (13) are arranged to overlap each other on the rear wall (6).

11. The electrolytic cell according to any one of claims 1 to 10, characterized in that: The bearing surface (19) extends laterally beyond the support parts (14, 15) at least on one side through an extension (26) of the support member (13).

12. The electrolytic cell according to any one of claims 1 to 11, characterized in that The arched portion (18) has an arch height (h1), and the support portions (14, 15) have a support height (h2), wherein when the arched portion (18) is not deflected, the ratio between the arch height (h1) and the support height (h2) is in the range of 1:3 to 1:

30.

13. The electrolytic cell according to claim 12, characterized in that When the arched portion (18) is not deflected, the ratio between the arch height (h1) and the support height (h2) is in the range of 1:10 to 1:20.

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