Alkaline water electrolytic tank end pressing plate, alkaline water electrolytic tank and anti-corrosion method

Abstract

The invention provides an alkaline water electrolyser end pressing plate, an alkaline water electrolyser and an anti-corrosion method, and the alkaline water electrolyser end pressing plate comprises an end pressing plate body; the flow channels comprise gas flow channels and / or alkali liquor flow channels, the more than two flow channels are arranged on the end pressing plate body, and the inner diameter of the inner end of each flow channel is smaller than that of the outer end of each flow channel; the anti-corrosion coating is arranged on the inner wall of at least one flow channel; and the lining anti-corrosion pipe is arranged on the inner side of the anti-corrosion coating on one side of the outer end of the flow channel provided with the anti-corrosion coating. According to the alkaline water electrolytic bath end pressing plate, the anti-corrosion coating is integrally arranged on the inner wall of the flow channel, the whole flow channel can be protected, and the outer end part which is prone to corrosion is reinforced through the lining anti-corrosion pipe to achieve the anti-corrosion effect.

Description

Technical Field

[0001] The present application relates to the technical field of hydrogen production by alkaline water electrolysis, and in particular to an end pressure plate of an alkaline water electrolyzer, an alkaline water electrolyzer and an anti-corrosion method. Background Art

[0002] Hydrogen energy has the advantages of being environmentally friendly, storable, and renewable. As policies supporting the development of the hydrogen energy industry are gradually introduced and implemented, hydrogen energy is ushering in new opportunities for development.

[0003] Alkaline water electrolysis is the mainstream process in the current market, and the electrolyzer is the core component of the electrolysis system. There are channels on the end plate of the electrolyzer to export the hydrogen and oxygen produced by the electrolyzer, but the gas usually carries the alkaline solution mist and is also exported from the channel, so this part is exposed to alkaline solution corrosion and gas scouring. In order to maintain the long-term stable operation of the electrolyzer system, this part needs to be protected.

[0004] The hydrogen produced by the electrolyzer equipment may leak after corrosion. As hydrogen is a flammable gas, its leakage poses a great safety risk. In addition, electrolytic cell corrosion will cause a large amount of metallic iron ions to enter the electrolytic cell circulation system. Excessive iron ions will affect electrode activity and reduce hydrogen production efficiency.

[0005] At present, the scheme of an alkaline water electrolyzer end pressure plate and an alkaline water electrolyzer (CN 217579083U) in the prior art is to loosely line a section of nickel tube in the outer through hole, and spot weld the outer port of the nickel tube to the flange hole of the end pressure plate. This method can only protect the outer circular hole section but not the inner long strip hole section, and because it is a loose lining method, there is a large gap between the nickel tube and the flange hole, and alkali liquid will enter the gap to cause gap corrosion. An alkaline water electrolyzer anti-cavitation structure (CN 212404305 U) in the prior art prevents alkali liquid corrosion by lining the pipeline with polytetrafluoroethylene, but this method can only protect the circular hole section.

[0006] Therefore, a solution is now needed to effectively protect the inner wall of the flow channel, so as to prevent the inner wall of the flow channel from being corroded, thereby causing safety accidents and reducing the hydrogen production efficiency. Summary of the invention

[0007] In order to solve the problems in the prior art, the present application provides an end pressure plate of an alkaline water electrolyzer, an alkaline water electrolyzer, and an anti-corrosion method for the end pressure plate of an alkaline water electrolyzer. The technical solution of the present application is as follows:

[0008] 1. An end pressure plate of an alkaline water electrolyzer, comprising:

[0009] End pressure plate body;

[0010] A flow channel, wherein the flow channel includes a gas flow channel and / or an alkali solution flow channel, and two or more of the flow channels are arranged on the end pressure plate body, and the inner diameter of the inner end of the flow channel is smaller than the inner diameter of the outer end;

[0011] An anti-corrosion coating, wherein the anti-corrosion coating is provided on the inner wall of at least one of the flow channels;

[0012] An inner lined anti-corrosion pipe is provided on the inner side of the anti-corrosion coating on the outer end side of the flow channel where the anti-corrosion coating is provided.

[0013] 2. The end pressure plate of the alkaline water electrolyzer as described in item 1, wherein:

[0014] The anti-corrosion coating is also provided around the opening of the flow channel of the inner wall and / or outer wall of the end pressure plate body; or, the anti-corrosion coating is provided entirely on the inner wall and / or outer wall of the end pressure plate body.

[0015] 3. The end plate of the alkaline water electrolyzer according to item 1 or 2, wherein:

[0016] The anti-corrosion coating is a nickel coating; and / or,

[0017] The thickness of the anti-corrosion coating is 0.05 to 1 mm (such as 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm or 0.9 mm), preferably 0.3 to 1 mm.

[0018] 4. The end pressure plate of the alkaline water electrolyzer according to item 1 or 2, wherein:

[0019] The anti-corrosion coating is formed by electroplating or chemical plating; and / or,

[0020] The anti-corrosion coating is one layer or more than two layers.

[0021] 5. The end pressure plate of the alkaline water electrolyzer as described in item 4, wherein:

[0022] The electroplating is brush plating.

[0023] 6. The end pressure plate of the alkaline water electrolyzer as described in item 5, wherein:

[0024] The electroplating solution of the brush plating is selected from a special nickel plating solution, a fast nickel plating solution, an alkaline nickel plating solution, a neutral nickel plating solution or a low-stress nickel plating solution.

[0025] 7. The end pressure plate of the alkaline water electrolyzer as described in item 1, wherein:

[0026] The material of the lining anti-corrosion pipe is nickel or nickel alloy.

[0027] 8. The end pressure plate of the alkaline water electrolyzer as described in item 7, wherein:

[0028] The lined anti-corrosion pipe is fixed to the inner side of the anti-corrosion coating in the flow channel by expansion connection; and / or,

[0029] The thickness of the lined anti-corrosion pipe is 0.5-8 mm (such as 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm or 8 mm), preferably 0.5-3 mm.

[0030] 9. The end pressure plate of the alkaline water electrolyzer as described in item 1, wherein:

[0031] The material of the lining anti-corrosion pipe is selected from polysulfone, polyarylsulfone, polyphenylene sulfide, polytetrafluoroethylene, polyethylene or polytetrafluoroethylene.

[0032] 10. The end pressure plate of the alkaline water electrolyzer as described in item 9, wherein:

[0033] The lined anti-corrosion pipe is fixedly connected to the inner side of the anti-corrosion coating in the flow channel by an adhesive; or,

[0034] The lined anti-corrosion pipe is fixedly connected to the inner side of the anti-corrosion coating in the flow channel through cladding and sintering processes.

[0035] 11. The end pressure plate of the alkaline water electrolyzer as described in item 1, wherein:

[0036] It also includes a sealing ring, which is arranged on the outer side wall of the end pressure plate body and surrounds the opening of the flow channel.

[0037] 12. The end pressure plate of the alkaline water electrolyzer as described in item 1, wherein:

[0038] More than two threaded holes are arranged around the opening of the flow channel on the outer side wall of the end pressure plate body.

[0039] 13. An end pressure plate of an alkaline water electrolyzer, comprising:

[0040] End pressure plate body;

[0041] A flow channel, wherein the flow channel includes a gas flow channel and / or an alkali solution flow channel, and two or more of the flow channels are arranged on the end pressure plate body, and the inner diameter of the inner end of the flow channel is smaller than the inner diameter of the outer end;

[0042] The inner lining anti-corrosion pipe is made of nickel or nickel alloy. The inner lining anti-corrosion pipe is located at the outer end of the flow channel and is expanded and fixed to the inner wall of the flow channel.

[0043] 14. The end plate of the alkaline water electrolyzer as described in item 13, wherein:

[0044] The thickness of the lined anti-corrosion pipe is 0.5-8 mm (such as 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm or 8 mm), preferably 0.5-3 mm.

[0045] 15. An alkaline water electrolyzer, comprising:

[0046] The end pressure plate of the alkaline water electrolyzer according to any one of items 1 to 14.

[0047] 16. A method for anti-corrosion of an end plate of an alkaline water electrolyzer, wherein:

[0048] The end pressure plate of the alkaline water electrolyzer comprises:

[0049] an end plate body; and,

[0050] A flow channel, wherein the flow channel includes a gas flow channel and / or an alkali solution flow channel, and two or more of the flow channels are arranged on the end pressure plate body, and the inner diameter of the inner end of the flow channel is smaller than the inner diameter of the outer end;

[0051] The anti-corrosion method comprises the following steps:

[0052] a step of providing an anti-corrosion coating, providing an anti-corrosion coating on an inner wall of at least one of the flow channels;

[0053] The step of setting an inner lining anti-corrosion pipe is to set an inner lining anti-corrosion pipe on the inner side of the anti-corrosion coating on the outer end side of the flow channel where the anti-corrosion coating is set.

[0054] 17. The antiseptic method according to item 16, wherein:

[0055] The step of providing the anti-corrosion coating is to provide the anti-corrosion coating on the inner wall of at least one of the flow channels by brush plating.

[0056] 18. The antiseptic method according to item 17, wherein:

[0057] Brush plating includes the following steps:

[0058] The pre-treatment step of brush plating is used to pre-treat the surface of the electroplating part;

[0059] Brush plating step, used to electroplate the surface of the plating area;

[0060] The post-treatment step of brush plating is used to clean and dry the surface of the electroplated area after brush plating.

[0061] 19. The antiseptic method according to item 16, wherein:

[0062] The brush plating pre-treatment step comprises:

[0063] Electrocleaning treatment: Use electrocleaning liquid to treat the surface of the electroplated area to remove oil stains on the surface of the electroplated area;

[0064] Surface pretreatment is used to remove the oxide film on the surface of the electroplated area and make the surface of the plated part present the crystalline structure of the metal.

[0065] 20. The antiseptic method according to item 19, wherein:

[0066] The electro-cleaning solution comprises: 20-28 g / L sodium hydroxide, 20-30 g / L anhydrous sodium carbonate, 40-58 g / L trisodium phosphate, 2-4 g / L sodium chloride, with a pH of 11-15; and / or,

[0067] The working voltage of electro-cleaning treatment is 8-15V, and the relative movement speed between the plating pen used for brush plating and the surface of the electroplating part is 3-8m / min.

[0068] 21. The antiseptic method according to item 19, wherein:

[0069] The surface pretreatment is to activate the surface of the electroplating part;

[0070] in,

[0071] During the activation treatment, the activation solution is composed of 5-90 g / L sulfuric acid and 100-120 g / L ammonium sulfate, with a pH of 0.1-5; and / or, the working voltage is 8-15 V, and the relative movement rate between the plating pen used for brush plating and the surface of the electroplating part is 5-10 m / min.

[0072] 22. The antiseptic method according to item 18, wherein:

[0073] The brush plating steps include:

[0074] Plating a transition layer, electroplating a transition layer with a thickness of 2μm to 50μm (such as 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm) on the surface of the electroplating part;

[0075] Plating a working layer: Plating a working layer on the surface of the transition layer.

[0076] 23. The antiseptic method according to item 22, wherein:

[0077] In plating the transition layer and the working layer, the following plating solutions are selected independently:

[0078] A special nickel plating solution comprising: 390-400 g / L nickel sulfate, 14-20 g / L nickel chloride, 20-28 mL / L hydrochloric acid and 68-72 mL / L acetic acid; or,

[0079] A fast nickel plating solution comprising: 230-280 g / L nickel sulfate, 80-125 mL / L ammonia water, 45-60 g / L ammonium citrate, 18-25 g / L ammonium acetate, 0.05-0.2 g / L ammonium oxalate, 25-35 g / L boric acid, and 1-3 g / L sulfuric acid;

[0080] An alkaline nickel plating solution comprising: 235-285 g / L nickel sulfate, 80-98 g / L sodium cyanide, 10-70 g / L boric acid, 20-35 g / L boric acid, and 0.05-0.1 g / L sodium dodecyl sulfate; or,

[0081] A neutral nickel plating solution comprising: 135-148 g / L nickel sulfate, 10-25 g / L sodium chloride, 52-68 g / L acetic acid and 40-60 mL / L ammonia water; or,

[0082] The low stress nickel plating solution comprises: 320-380 g / L nickel sulfate, 10-40 mL / L acetic acid, 15-35 g / L sodium acetate, 0.02-0.15 g / L sodium p-aminobenzenesulfonate and 0.005-0.1 g / L sodium dodecyl sulfate.

[0083] 24. The antiseptic method according to item 16, wherein:

[0084] The material of the lining anti-corrosion pipe is nickel or nickel alloy.

[0085] 25. The antiseptic method according to item 24, wherein:

[0086] The steps for setting up lined anti-corrosion pipes are:

[0087] An inner lining anti-corrosion pipe is provided by expansion connection on the inner side of the anti-corrosion coating at one side of the outer end of the flow channel provided with the anti-corrosion coating.

[0088] 26. The antiseptic method according to item 16, wherein:

[0089] The material of the lining anti-corrosion pipe is selected from polysulfone, polyarylsulfone, polyphenylene sulfide, polytetrafluoroethylene, polyethylene or polytetrafluoroethylene.

[0090] 27. The antiseptic method according to item 26, wherein:

[0091] The steps for setting up lined anti-corrosion pipes are:

[0092] The inner side of the anti-corrosion coating at the outer end of the flow channel provided with the anti-corrosion coating is fixedly connected to the lined anti-corrosion pipe by an adhesive, or the lined anti-corrosion pipe is fixedly connected by a cladding or sintering process.

[0093] By means of the above-mentioned alkaline water electrolyzer end pressure plate provided by the present application, an anti-corrosion coating is provided on the entire inner wall of the flow channel, thereby being able to prevent the inner wall of the flow channel from being corroded as a whole; at the same time, since the inner diameter of the outer end of the flow channel is larger than the inner diameter of the inner end, the outer end of the flow channel is more susceptible to impact and causes serious corrosion. In this embodiment, by further providing a lining anti-corrosion pipe, the corrosion here can be reduced. That is, the technical solution of the above-mentioned alkaline water electrolyzer end pressure plate can protect the entire flow channel, and the outer end part prone to corrosion is strengthened by the lining anti-corrosion pipe to achieve the anti-corrosion effect.

[0094] The above description is only an overview of the technical solution of the present application. In order to make the technical means of the present application clearer and to enable those skilled in the art to implement it according to the contents of the specification, and to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are exemplified below. BRIEF DESCRIPTION OF THE DRAWINGS

[0095] Figure 1 : Schematic diagram of the front view of the end pressure plate;

[0096] Figure 2 : Figure 1 A magnified schematic diagram of the structure inside the middle A position;

[0097] Figure 3 : Schematic diagram of the flow channel structure of the end pressure plate.

[0098] Description of reference numerals:

[0099] 1. End pressure plate body; 2. Flow channel; 3. Anti-corrosion coating; 4. Lined anti-corrosion pipe; 5. Sealing ring; 6. Threaded hole. DETAILED DESCRIPTION

[0100] The following embodiments of the present application are only used to illustrate the specific embodiments of the present application, and these embodiments cannot be understood as limiting the present application. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present application are deemed to be equivalent replacement methods and fall within the scope of protection of the present application.

[0101] Those skilled in the art should understand that, in the disclosure of the present application, the terms "first", "second", "third", "fourth", "fifth", etc. are only used to distinguish different structures, but do not limit the number, connection relationship, etc. of specific structures; in addition, the directions or positional relationships indicated by "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms cannot be understood as limitations on the present application.

[0102] This embodiment provides an end pressure plate of an alkaline water electrolyzer, such as Figure 1 to Figure 3 As shown, including:

[0103] End pressure plate body 1;

[0104] A flow channel 2, wherein the flow channel 2 includes a gas flow channel and / or a liquid flow channel, and more than two flow channels 2 are arranged on the end pressure plate body 1, and the inner diameter of the inner end of the flow channel 2 is smaller than the inner diameter of the outer end;

[0105] An anti-corrosion coating 3 is provided on the inner wall of at least one of the flow channels 2;

[0106] An inner lined anti-corrosion pipe 4 is provided on the inner side of the anti-corrosion coating 3 on the outer end side of the flow channel 2 where the anti-corrosion coating 3 is provided.

[0107] It should be noted that, in order to simply and clearly indicate the position in the flow channel, the application refers to the side of the flow channel close to the inside of the electrolytic cell as the inner end, and the side of the flow channel close to the outside of the electrolytic cell as the outer end. Figure 3 As shown, the left side of the flow channel is the inner end and the right side is the outer end.

[0108] The material of the end pressure plate body is generally a metal material, such as iron or iron alloy (such as carbon steel, alloy steel, structural steel, steel forgings). In this embodiment, the end pressure plate body is a low-alloy high-strength structural steel (grade Q355B in GB / t1591).

[0109] In addition, the inner diameter in the present application refers to the diameter of an area equivalent circle. In the present embodiment, the cross-sectional shape of the flow channel is consistent with the prior art, that is, the inner end cross-sectional shape is waist-shaped and the outer end cross-sectional shape is circular. Of course, the cross-sectional shape of the flow channel of the present application is not limited thereto, and those skilled in the art can set the flow channel with different cross-sectional shapes as needed.

[0110] Generally, a flow channel 2 is provided on the end pressure plate of the alkaline water electrolyzer, such as Figure 1As shown, the upper flow channel 2 (gas flow channel) is mainly used for gas (hydrogen or oxygen) to flow out, and the lower flow channel 2 (alkali solution flow channel) is used for the circulation of alkaline water.

[0111] like Figure 3 As shown, for the gas flow channel, this embodiment provides an anti-corrosion coating 3 on the inner wall of the flow channel 2 as a whole, thereby preventing the inner wall of the flow channel 2 from being corroded (cavitation and alkali corrosion); at the same time, since the inner diameter of the outer end of the flow channel 2 is larger than the inner diameter of the inner end, the outer end of the flow channel 2 is more susceptible to impact and causes serious corrosion. In this embodiment, an inner lining anti-corrosion pipe 4 is further specially provided, thereby reducing the corrosion here. In addition, those skilled in the art know that providing a corresponding anti-corrosion coating 3 and an inner lining anti-corrosion pipe 4 in the alkali solution flow channel can also achieve a corresponding anti-corrosion effect.

[0112] That is, through the above technical solution of this embodiment, the entire flow channel can be protected, and the outer end part prone to corrosion is strengthened by the lining anti-corrosion pipe 4 to achieve the anti-corrosion effect.

[0113] When the anti-corrosion coating is only provided on the inner wall of the flow channel 2, only the flow channel 2 of the end pressure plate contacts the alkali solution, and the surface area of ​​the flow channel only accounts for about 1% of the entire surface area of ​​the end pressure plate, thereby reducing the manufacturing cost. Figure 3 The left side of the middle pressure plate body 1) and / or the outer side wall (i.e. Figure 3 The anti-corrosion coating is also provided around the opening of the flow channel (on the right side of the middle end pressure plate body 1), and in this case, the flow channel 2 and the part of the end pressure plate body 1 near the flow channel 2 that is susceptible to corrosion can be protected at the same time. Further, the anti-corrosion coating is provided on the entire inner wall and / or outer wall of the end pressure plate body 1, and in this case, the entire end pressure plate body can be well protected, but the manufacturing cost is also increased.

[0114] In one embodiment, the anti-corrosion coating 3 is a nickel coating. At this time, when the thickness of the anti-corrosion coating 3 is 0.05-1 mm, it can ensure that the anti-corrosion coating can be firmly attached to the inner wall of the flow channel, and can avoid cracks during the preparation or use of the coating, and can also play a good anti-corrosion role with a lower coating material usage.

[0115] Regarding the nickel coating, it can be formed by electroplating or chemical plating. When the thickness of the coating is large, the anti-corrosion coating can be multi-layered. Specifically, when the anti-corrosion coating is prepared by electroplating or chemical plating, two or more electroplating solutions can be selected and electroplating or chemical plating can be performed multiple times to form a multi-layer coating. This can not only quickly increase the thickness, but also reduce the internal stress of the coating and ensure the quality of the coating. The electroplating solution of each coating can be the same or different. When different, it can be alternately brush-plated in layers, and a combination of different coatings can be selected according to the corrosion resistance and bonding strength of various coatings.

[0116] When the anti-corrosion coating is only provided on the inner wall of the flow channel 2, the anti-corrosion coating can be provided on the inner wall of the flow channel 2 by the brush plating process in the electroplating, and the surface area of ​​the inner wall of the flow channel only accounts for about 1% of the overall surface area of ​​the end pressure plate, thereby greatly reducing the use of nickel and thus reducing the cost. Specifically, the process route is surface finishing, surface cleaning, electro-cleaning treatment, water washing, activation treatment, transition layer plating, working layer plating, and post-plating treatment, and finally a nickel plating layer with a thickness of 0.05 to 1 mm is formed on the inner surface of the pipeline.

[0117] The brush plating of the present application is also called metal pen plating or rapid electroplating. It is a process in which a plating pen filled with plating solution is used as an anode to discharge and crystallize metal ions on the surface of the negative electrode (workpiece) to form a metal coating. The plating pen is an insoluble anode. During brush plating, the plating pen contacts the surface of the workpiece and moves continuously.

[0118] Specifically, the brush plating includes the following steps: a brush plating pre-treatment step for pre-treating the surface of the plating area; a brush plating step for plating the surface of the plating area; and a brush plating post-treatment step for cleaning and drying the surface of the plating area after brush plating.

[0119] The surface of the electroplated part in this embodiment refers to the inner wall of the flow channel that needs to be electroplated as mentioned above; the inner side wall and / or outer side wall of the end pressure plate body around the opening of the flow channel; and / or the entire inner side wall and / or outer side wall of the end pressure plate body. In this embodiment, brush plating mainly refers to electroplating the inner wall of the flow channel that needs to be electroplated.

[0120] In this embodiment, the brush plating pre-treatment step includes:

[0121] Electrocleaning treatment: Use electrocleaning liquid to treat the surface of the electroplated area to remove oil stains on the surface of the electroplated area;

[0122] Surface pretreatment is used to remove the oxide film on the surface of the electroplated area and make the surface of the plated part present a metal crystalline structure, thereby ensuring that the metal ions can be reduced on the fresh substrate surface and firmly bonded to the substrate to form a coating with good strength.

[0123] The electro-cleaning liquid contains: 20-28 g / L sodium hydroxide, 20-30 g / L anhydrous sodium carbonate, 40-58 g / L trisodium phosphate, 2-4 g / L sodium chloride, and a pH of 11-15 (pH=13 in this embodiment). The electro-cleaning liquid has a strong degreasing ability and a slight derusting effect. When the electro-cleaning liquid is used for electro-cleaning, the working voltage is 8-15 V, and the relative movement speed between the plating pen and the surface of the electroplating part is 3-8 m / min, that is, the plating pen is connected to the anode, and the surface of the electroplating part is connected to the cathode.

[0124] The surface pretreatment is to activate the surface of the electroplating part and / or perform sandblasting.

[0125] In the activation treatment, the activation solution is composed of 5-90 g / L sulfuric acid and 100-120 g / L ammonium sulfate, with a pH of 0.1-5 (pH=0.4 in this embodiment). During activation, the surface of the electroplated part is connected to the positive pole of the power supply, the plating pen is connected to the negative pole of the power supply, and the plating pen is dipped in the activation solution and repeatedly smeared on the surface of the electroplated part, the working voltage is 8-15 V, and the relative movement speed between the plating pen and the surface of the electroplated part is 5-10 m / min.

[0126] In the sandblasting process, the particle size of the silica sand used for sandblasting is 0.2-1mm, the compressed air pressure is 0.3-0.5Mpa, and the nozzle is sprayed at an angle of 20°-30° to the surface of the electroplated part. Under this process condition, the surface oil, stains, and oxide film can be cleaned, and at the same time, the roughness of the workpiece can be increased (surface roughness Rz20-70μm), so that the bonding force between the nickel plating layer and the surface of the electroplated part is better.

[0127] In addition, before the electro-cleaning treatment, the surface of the electroplated area can be preliminarily treated, such as surface finishing: use a wire brush and sandpaper to grind the rust on the surface of the electroplated area, and surface cleaning: use a dry cloth dipped in alcohol to wipe the inside of the tube and the surrounding area of ​​the surface to be plated (such as within 3 cm), so as to make the surface of the electroplated area bright, smooth and clean.

[0128] In this embodiment, the brush plating steps include: plating a transition layer, plating a transition layer with a thickness of 2 μm to 50 μm on the surface of the plating part; and plating a working layer, plating the working layer on the surface of the transition layer.

[0129] Among them, the plating of transition layer can not only improve the bonding strength between the substrate and the coating, improve the plating property of the substrate metal, and improve the bonding strength with the working coating. Some metals are difficult to be brush plated directly on the substrate, but also prevent the corrosion of the substrate metal by the corrosive plating solution.

[0130] Specifically, in plating the transition layer and the working layer, the electroplating solution used is:

[0131] A special nickel plating solution comprises: 390-400 g / L of nickel sulfate, 14-20 g / L of nickel chloride, 20-28 mL / L of hydrochloric acid and 68-72 mL / L of acetic acid. The special nickel has a strong bonding force with the surface of the electroplated part (such as the inner wall of the flow channel) and has good wear resistance. In the present embodiment, when plating the transition layer, it is preferred to use this special nickel plating solution for electro-brush plating. In order to make it well bonded with the surface of the electroplated part, it is usually directly plated with special nickel without water rinsing after activation. During operation, the power is not turned on first, the surface of the plating part is connected to the negative pole of the power supply, and the surface of the plating part is wiped once with a plating pen dipped in the solution. After power is turned on, the surface of the plating part is first plated once with 18V impact, and then reduced to 12V. The relative movement rate between the plating pen and the surface of the plating part is 5-10 m / min.

[0132] A fast nickel plating solution, comprising: 230-280 g / L nickel sulfate, 80-125 mL / L ammonia, 45-60 g / L ammonium citrate, 18-25 g / L ammonium acetate, 0.05-0.2 g / L ammonium oxalate, 25-35 g / L boric acid, 1-3 g / L sulfuric acid. Specifically, it comprises: 250 g / L nickel sulfate, 100 mL / L ammonia, 56 g / L ammonium citrate, 23 g / L ammonium acetate, 0.1 g / L ammonium oxalate, 30 g / L boric acid, 1 g / L sulfuric acid, slightly alkaline (pH = 7.5-7.8), wherein the nickel ion content is 53 g / L. The process steps are as follows: the working voltage is 10-15 V, the relative movement rate between the plating pen and the surface of the electroplating part is 6-15 m / min, and the surface of the plating part is connected to the negative pole of the power supply. After testing, the hardness of the coating is about 650 HB.

[0133] Alkaline nickel plating solution, which contains: 235-285g / L nickel sulfate, 80-98g / L sodium cyanide, 10-70g / L, 20-35g / L boric acid and 0.05-0.1g / L sodium dodecyl sulfate. Specifically, it contains: 260g / L nickel sulfate, 85g / L sodium cyanide, 55g / L, 25g / L boric acid and 0.08g / L sodium dodecyl sulfate, pH = 8.5, wherein the nickel ion content is 54.4g / L. The process specifications are as follows: working voltage 8-14V, relative movement speed between the plating pen and the surface of the electroplating part 8-12m / min, and the surface of the plating part is connected to the negative pole of the power supply. The obtained coating has fine structure, uniform color, low stress, and the hardness is 500HB after testing.

[0134] Neutral nickel plating solution, which contains: nickel sulfate 135 ~ 148g / L, sodium chloride 10 ~ 25g / L, acetic acid 52 ~ 68g / L and ammonia 40 ~ 60mL / L. Specifically, it contains: nickel sulfate 138g / L, sodium chloride 18g / L, acetic acid 60g / L and ammonia 50ml / L, pH = 7, wherein the nickel ion content is 28g / L. The process specifications are as follows: working voltage 10 ~ 14V, the relative movement rate between the plating pen and the surface of the electroplating part is 6 ~ 10m / min, and the surface of the plating part is connected to the negative pole of the power supply. The obtained coating has a fine structure, is silvery white, has good corrosion resistance, and has a hardness of 500HB.

[0135] Low stress nickel plating solution, which contains: nickel sulfate 320 ~ 380g / L, acetic acid 10 ~ 40mL / L, sodium acetate 15 ~ 35g / L, sodium p-aminobenzenesulfonate 0.02 ~ 0.15g / L and sodium dodecyl sulfate 0.005 ~ 0.1g / L. Specifically, it contains: nickel sulfate 350g / L, acetic acid 32mL / L, sodium acetate 18g / L, sodium p-aminobenzenesulfonate 0.1g / L and sodium dodecyl sulfate 0.01g / L, pH = 3.5, wherein the nickel ion content is 75g / L. The process specifications are as follows: first preheat the plating solution to 50 ° C, the working voltage is 8 ~ 14V, the relative movement speed between the plating pen and the surface of the electroplating part is 6 ~ 10m / min, and the surface of the plating part is connected to the negative pole of the power supply. The hardness of the coating is 350HB.

[0136] In this embodiment, the post-treatment step of brush plating may specifically include washing residual plating solution on the surface of the electroplating part with water and drying the surface of the electroplating part with a blower or the like.

[0137] When the inner side wall (i.e. Figure 3 The left side of the middle pressure plate body) and / or the outer side wall (i.e. Figure 3 The anti-corrosion coating is also provided around the opening of the flow channel (on the right side of the middle pressure plate body). At this time, the flow channel outlet of the end pressure plate to the corresponding edge of the end pressure plate can be immersed in the chemical plating solution to obtain a local chemical nickel plating layer.

[0138] When the anti-corrosion coating 3 is provided on the entire end pressure plate body 1, the entire end pressure plate can be chemically plated. In this case, more nickel material is used, so the production cost is higher.

[0139] In one embodiment, the material of the lining anti-corrosion pipe 4 is nickel or nickel alloy. At this time, the lining anti-corrosion pipe 4 can be fixed with the inner wall of the anti-corrosion coating in the flow channel by expansion, so that the lining anti-corrosion pipe 4 is in contact with the inner wall of the flow channel without gap, and the welding process of the metal lining pipe is omitted, avoiding stress corrosion at the welding point.

[0140] Specifically, the lined anti-corrosion pipe described in this embodiment is a nickel pipe with a thickness of 0.5 to 8 mm, made of nickel or nickel alloy, and its outer diameter is 0.1 to 1 mm smaller than the inner diameter of the anti-corrosion coating 4 at the outer end of the flow channel 2 (the cross section of the outer end of the flow channel 2 in this embodiment is circular). A hydraulic tube expander is used to expand the nickel tube and the inner wall of the hole tightly. The expansion pressure can be selected according to the following formula:

[0141]

[0142]

[0143]

[0144] Wherein, P is the pressure required for the expansion of the nickel-lined tube; C is the expansion pressure amplification factor (C value is: 1.70 ~ 1.85); σ sp is the yield strength of the end plate material; σ st is the yield strength of the nickel lined tube; do is the outer diameter of the liner; di is the inner diameter of the liner; Di is the tube hole size; B is the minimum distance between adjacent tube holes.

[0145] In one embodiment, the material of the lining anti-corrosion pipe 4 is selected from polysulfone, polyarylsulfone, polyphenylene sulfide, polytetrafluoroethylene, polyethylene or polytetrafluoroethylene.

[0146] Specifically, the lined anti-corrosion pipe 4 can be fixedly connected to the inner wall of the anti-corrosion coating 3 by an adhesive. The lined anti-corrosion pipe 4 can also be fixedly connected to the inner wall of the anti-corrosion coating 3 by a cladding or sintering process.

[0147] In one embodiment, Figure 3 As shown, the end pressure plate of the alkaline water electrolyzer further includes a sealing ring 5 , which is arranged on the outer side wall of the end pressure plate body 1 and surrounds the opening of the flow channel 2 .

[0148] The sealing ring 5 can be provided to facilitate the connection of the opening at the outer end of the flow channel 2 with other pipelines to play a sealing role.

[0149] In one embodiment, Figure 3 As shown, more than two threaded holes 6 are provided around the opening of the flow channel on the outer side wall of the end pressure plate body.

[0150] By providing the threaded hole 6, it is possible to facilitate flange connection of other pipelines at the opening at the outer end of the flow channel 2.

[0151] This embodiment provides another end pressure plate of an alkaline water electrolyzer, comprising:

[0152] End pressure plate body;

[0153] A flow channel, wherein the flow channel includes a gas flow channel and / or an alkali solution flow channel, and two or more of the flow channels are arranged on the end pressure plate body, and the inner diameter of the inner end of the flow channel is smaller than the inner diameter of the outer end;

[0154] The inner lining anti-corrosion pipe is made of nickel or nickel alloy. The inner lining anti-corrosion pipe is located at the outer end of the flow channel and is expanded and fixed to the inner wall of the flow channel.

[0155] Specifically, the lined anti-corrosion tube described in this embodiment is a nickel tube with a thickness of 0.5 to 8 mm, made of nickel or nickel alloy, and its outer diameter is 0.1 to 1 mm smaller than the inner diameter of the outer end of the flow channel (the cross-section of the outer end of the flow channel in this embodiment is circular). A hydraulic tube expander is used to expand the nickel tube tightly against the inner wall of the hole.

[0156] Those skilled in the art know that the inner lining anti-corrosion pipe 4 made of nickel or nickel alloy can be fixed to the inner wall of the outer end of the flow channel 2 by expansion. On the one hand, since the inner diameter of the outer end of the flow channel 2 is larger than the outer diameter of the inner end, the outer end of the flow channel 2 is more susceptible to impact and causes serious corrosion. The present embodiment can reduce the alkali corrosion here by providing the inner lining anti-corrosion pipe 4; on the other hand, by expansion fixing, the inner lining anti-corrosion pipe 4 can be made to contact the inner wall of the flow channel 2 without gaps, preventing the alkali solution from entering between the inner lining anti-corrosion pipe 4 and the inner wall of the flow channel 2 and corroding the inner wall of the flow channel 2, and no welding process of the metal lining pipe is required, thus avoiding stress corrosion at the welding point.

[0157] Based on the corresponding alkaline water electrolyzer end pressure plates provided in the above embodiments, those skilled in the art know that the above alkaline water electrolyzer end pressure plates can be applied to alkaline water electrolyzers for hydrogen production by alkaline water electrolysis. In addition, through the introduction of the above brush plating and lining anti-corrosion pipe setting methods, those skilled in the art know that the present application also provides an anti-corrosion method for the end pressure plates of alkaline water electrolyzers, and the end pressure plates of alkaline water electrolyzers are anti-corroded by the above brush plating and lining anti-corrosion pipes.

[0158] Example

[0159] The experimental methods used below are conventional methods unless otherwise specified.

[0160] Unless otherwise specified, the materials and reagents used below can be obtained from commercial sources.

[0161] Example 1

[0162] This embodiment provides a method for providing an anti-corrosion coating and an anti-corrosion lining pipe on an end pressure plate of an alkaline water electrolyzer, comprising the following steps:

[0163] 1. Use a dry cloth dipped in alcohol to clean the inside of the tube and the surface of the electroplated part (inner wall of the flow channel) within 3 cm. Use a wire brush and sandpaper to polish some rust to make the surface bright, smooth and clean.

[0164] 2. Use electro-cleaning liquid to electro-clean the surface of the plated parts treated above, with the surface of the electroplated part as the cathode and the plating pen as the anode, the working voltage is 10V, and the relative movement speed between the plating pen and the surface of the electroplated part is 3m / min. The electro-cleaning liquid contains: 26g / L sodium hydroxide, 20g / L anhydrous sodium carbonate, 52g / L trisodium phosphate, and 2.6g / L sodium chloride.

[0165] 3. Use activation solution to activate the surface of the electroplated part after electrocleaning. During the activation treatment, the surface of the electroplated part is used as the anode, the plating pen is used as the cathode, the output voltage is 15V, the relative movement rate between the plating pen and the surface of the electroplated part is 5m / min, and the activation time is 10s. The activation solution contains: 75g / L sulfuric acid and 105g / L ammonium sulfate, with a pH of 0.4.

[0166] 4. Use brush plating liquid to perform brush plating on the surface of the electroplated part after activation treatment. The current density during brush plating is 20A / m 2 The brush plating time is 5 minutes. The brush plating solution contains: 390g / L nickel sulfate, 16g / L nickel chloride, 23mL / L hydrochloric acid and 70mL / L acetic acid. First, a thin layer is plated as a transition layer, and then the working layer is plated. The thickness of the electroplating layer (anti-corrosion coating) is 0.3mm.

[0167] 5. Wash the surface of the electroplated area with clean water and dry it for 30 minutes.

[0168] 6. Select a liner (nickel tube) with a thickness of 4mm that is 1mm smaller than the diameter of the round tube section . Insert the nickel tube into the straight pipe section (outer end of the flow channel) until it reaches the root of the circular hole of the end pressure plate.

[0169] 7. Before expanding the tube, place a baffle barrier in front of the tube expansion gun head (or opposite to the straight tube). Insert the tube expansion head into the tube and move it forward, backward, left and right, keeping the center of the gun head aligned with the center of the tube. When the tube is expanded and the pressure is increased, put the tube expansion head and the liquid bag on the thick-walled tube. Place the tube in the expansion area to expand, adjust the expansion pressure holding time to 3s, and the expansion pressure: 285~301Mpa.

[0170] 8. After expansion, each pipe opening should be compared and checked to see if there are any cracks in the expanded part, and if there are no drastic changes in the expanded transition part. The measured inner diameter is about 82.6mm.

[0171] After the anti-corrosion coating and the lining anti-corrosion pipe are arranged on the end pressure plate of the alkaline water electrolyzer by adopting the above scheme, the end pressure plate is used in the electrolyzer for producing hydrogen by electrolysis.

[0172] When the electrolytic cell was used for 6 months and 2 years, it was observed that there was no corrosion in the waist-shaped hole of the end pressure plate (the inner end of the flow channel); after the nickel tube was removed, there was no corrosion on the inner wall of the straight pipe section (the outer end of the flow channel). In contrast, when the applicant used the prior art solution (no anti-corrosion coating was set in the flow channel), the waist-shaped hole (the inner end of the flow channel) was obviously corroded and thinned when the equipment was overhauled and removed after 6 months of use, and corroded rust and rust appeared on the inner wall of the straight pipe section (the outer end of the flow channel).

[0173] Make simulated specimens to conduct accelerated corrosion tests in the laboratory:

[0174] Normal use conditions: temperature 90°C, medium: 30% KOH solution, hydrogen, gas alkali flow rate: 3.5m / s;

[0175] Accelerated test conditions: temperature 120℃, air flow velocity: 7m / s, medium: 40% KOH. After 168 hours of observation, no corrosion was found on the brush-plated surface and the inner wall after the nickel tube was removed.

[0176] Although the embodiments of the present application are described above, the present application is not limited to the above specific embodiments and application fields, and the above specific embodiments are merely illustrative and instructive, rather than restrictive. A person of ordinary skill in the art can make many forms under the guidance of this specification and without departing from the scope of protection of the claims of the present application, all of which belong to the scope of protection claimed in the present application.

Claims

1. An end plate of an alkaline water electrolyzer, wherein: include: End pressure plate body; A flow channel, wherein the flow channel includes a gas flow channel and / or an alkali solution flow channel, and two or more of the flow channels are arranged on the end pressure plate body, and the inner diameter of the inner end of the flow channel is smaller than the inner diameter of the outer end; An anti-corrosion coating is provided on the inner wall of at least one of the flow channels; An inner lined anti-corrosion pipe is arranged on the inner side of the anti-corrosion coating on the outer end side of the flow channel where the anti-corrosion coating is arranged.

2. The end plate of the alkaline water electrolyzer according to claim 1, wherein: The anti-corrosion coating is also provided around the opening of the flow channel of the inner wall and / or outer wall of the end pressure plate body; or, the anti-corrosion coating is provided entirely on the inner wall and / or outer wall of the end pressure plate body.

3. The end pressure plate of the alkaline water electrolyzer according to claim 1 or 2, wherein: The anti-corrosion coating is a nickel coating; and / or, The thickness of the anti-corrosion coating is 0.05 to 1 mm, preferably 0.3 to 1 mm.

4. The end pressure plate of the alkaline water electrolyzer according to claim 1 or 2, wherein: The anti-corrosion coating is formed by electroplating or chemical plating; and / or, The anti-corrosion coating is one layer or more than two layers.

5. The end plate of the alkaline water electrolyzer according to claim 4, wherein: The electroplating is brush plating.

6. The end plate of the alkaline water electrolyzer according to claim 5, wherein: The electroplating solution of the brush plating is selected from a special nickel plating solution, a fast nickel plating solution, an alkaline nickel plating solution, a neutral nickel plating solution or a low-stress nickel plating solution.

7. The end plate of the alkaline water electrolyzer according to claim 1, wherein: The material of the lining anti-corrosion pipe is nickel or nickel alloy.

8. The end plate of the alkaline water electrolyzer according to claim 7, wherein: The lined anti-corrosion pipe is fixed to the inner side of the anti-corrosion coating in the flow channel by expansion connection; and / or, The thickness of the lined anti-corrosion pipe is 0.5 to 8 mm, preferably 0.5 to 3 mm.

9. The end plate of the alkaline water electrolyzer according to claim 1, wherein: The material of the lining anti-corrosion pipe is selected from polysulfone, polyarylsulfone, polyphenylene sulfide, polytetrafluoroethylene, polyethylene or polytetrafluoroethylene.

10. The end plate of the alkaline water electrolyzer according to claim 9, wherein: The lined anti-corrosion pipe is fixedly connected to the inner side of the anti-corrosion coating in the flow channel by an adhesive; or, The lined anti-corrosion pipe is fixedly connected to the inner side of the anti-corrosion coating in the flow channel through cladding and sintering processes.

11. The end plate of the alkaline water electrolyzer according to claim 1, wherein: It also includes a sealing ring, which is arranged on the outer side wall of the end pressure plate body and surrounds the opening of the flow channel.

12. The end plate of the alkaline water electrolyzer according to claim 1, wherein: More than two threaded holes are arranged around the opening of the flow channel on the outer side wall of the end pressure plate body.

13. An end plate of an alkaline water electrolyzer, wherein: include: End pressure plate body; A flow channel, wherein the flow channel includes a gas flow channel and / or an alkali solution flow channel, and two or more of the flow channels are arranged on the end pressure plate body, and the inner diameter of the inner end of the flow channel is smaller than the inner diameter of the outer end; The inner lining anti-corrosion pipe is made of nickel or nickel alloy. The inner lining anti-corrosion pipe is located at the outer end of the flow channel and is expanded and fixed to the inner wall of the flow channel.

14. The end plate of the alkaline water electrolyzer according to claim 13, wherein: The thickness of the lined anti-corrosion pipe is 0.5 to 8 mm, preferably 0.5 to 3 mm.

15. An alkaline water electrolyzer, wherein: include: The end pressure plate of the alkaline water electrolyzer according to any one of claims 1 to 14.

16. A method for anticorrosion of an end plate of an alkaline water electrolyzer, wherein: The end pressure plate of the alkaline water electrolyzer comprises: an end plate body; and, A flow channel, wherein the flow channel includes a gas flow channel and / or an alkali solution flow channel, and two or more of the flow channels are arranged on the end pressure plate body, and the inner diameter of the inner end of the flow channel is smaller than the inner diameter of the outer end; The anti-corrosion method comprises the following steps: a step of providing an anti-corrosion coating, providing an anti-corrosion coating on an inner wall of at least one of the flow channels; The step of setting an inner lining anti-corrosion pipe is to set an inner lining anti-corrosion pipe on the inner side of the anti-corrosion coating on the outer end side of the flow channel where the anti-corrosion coating is set.

17. The anticorrosion method according to claim 16, wherein: The step of providing the anti-corrosion coating is to provide the anti-corrosion coating on the inner wall of at least one of the flow channels by brush plating.

18. The antiseptic method according to claim 17, wherein: Brush plating includes the following steps: The pre-treatment step of brush plating is used to pre-treat the surface of the electroplating part; Brush plating step, used to electroplate the surface of the plating area; The post-treatment step of brush plating is used to clean and dry the surface of the electroplated area after brush plating.

19. The antiseptic method according to claim 16, wherein: The brush plating pre-treatment step comprises: Electrocleaning treatment: Use electrocleaning liquid to treat the surface of the electroplated area to remove oil stains on the surface of the electroplated area; Surface pretreatment is used to remove the oxide film on the surface of the electroplated area and make the surface of the plated part present the crystalline structure of the metal.

20. The anticorrosion method according to claim 19, wherein: The electro-cleaning solution comprises: 20-28 g / L sodium hydroxide, 20-30 g / L anhydrous sodium carbonate, 40-58 g / L trisodium phosphate, 2-4 g / L sodium chloride, with a pH of 11-15; and / or, The working voltage of electro-cleaning treatment is 8-15V, and the relative movement speed between the plating pen used for brush plating and the surface of the electroplating part is 3-8m / min.

21. The antiseptic method according to claim 19, wherein: The surface pretreatment is to activate the surface of the electroplating part; in, During the activation treatment, the activation solution is composed of 5-90 g / L sulfuric acid and 100-120 g / L ammonium sulfate, with a pH of 0.1-5; and / or, the working voltage is 8-15 V, and the relative movement rate between the plating pen used for brush plating and the surface of the electroplating part is 5-10 m / min.

22. The antiseptic method according to claim 18, wherein: The brush plating steps include: Plating a transition layer, electroplating a transition layer of 2μm to 50μm thick on the surface of the electroplating part; Plating a working layer: Plating a working layer on the surface of the transition layer.

23. The antiseptic method according to claim 22, wherein: In plating the transition layer and the working layer, the following plating solutions are selected independently: A special nickel plating solution comprising: 390-400 g / L nickel sulfate, 14-20 g / L nickel chloride, 20-28 mL / L hydrochloric acid and 68-72 mL / L acetic acid; or, A fast nickel plating solution comprising: 230-280 g / L nickel sulfate, 80-125 mL / L ammonia water, 45-60 g / L ammonium citrate, 18-25 g / L ammonium acetate, 0.05-0.2 g / L ammonium oxalate, 25-35 g / L boric acid, and 1-3 g / L sulfuric acid; An alkaline nickel plating solution comprising: 235-285 g / L nickel sulfate, 80-98 g / L sodium cyanide, 10-70 g / L boric acid, 20-35 g / L boric acid, and 0.05-0.1 g / L sodium dodecyl sulfate; or, A neutral nickel plating solution comprising: 135-148 g / L nickel sulfate, 10-25 g / L sodium chloride, 52-68 g / L acetic acid and 40-60 mL / L ammonia water; or, The low stress nickel plating solution comprises: 320-380 g / L nickel sulfate, 10-40 mL / L acetic acid, 15-35 g / L sodium acetate, 0.02-0.15 g / L sodium p-aminobenzenesulfonate and 0.005-0.1 g / L sodium dodecyl sulfate.

24. The antiseptic method according to claim 16, wherein: The material of the lining anti-corrosion pipe is nickel or nickel alloy.

25. The antiseptic method according to claim 24, wherein: The steps for setting up lined anti-corrosion pipes are: An inner lining anti-corrosion pipe is provided by expansion connection on the inner side of the anti-corrosion coating at one side of the outer end of the flow channel provided with the anti-corrosion coating.

26. The antiseptic method according to claim 16, wherein: The material of the lining anti-corrosion pipe is selected from polysulfone, polyarylsulfone, polyphenylene sulfide, polytetrafluoroethylene, polyethylene or polytetrafluoroethylene.

27. The antiseptic method according to claim 26, wherein: The steps for setting up lined anti-corrosion pipes are: The inner side of the anti-corrosion coating at the outer end of the flow channel provided with the anti-corrosion coating is fixedly connected to the lined anti-corrosion pipe by an adhesive, or the lined anti-corrosion pipe is fixedly connected by a cladding or sintering process.

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