Adding device of solubility regulator

Abstract

The utility model discloses an adding device of a solubility regulator. The adding device is applied to the electrolytic bath, the adding device comprises at least one group of adding components, and each adding component comprises a storage unit for storing a solubility regulator; the first end of the adding valve is connected with the storage unit, and the second end of the adding valve is connected with the pipeline assembly, the hydrogen gas-liquid separator, the oxygen gas-liquid separator or the alkali liquor pumping assembly; and the adding pump is arranged between the storage unit and the adding valve so as to pump a solubility regulator into the alkali liquor of the electrolytic bath. According to the adding device of the solubility regulator, the solubility regulator can be added into the electrolytic bath to assist in reducing the solubility of metal ions in alkali liquor, so that the concentration of the metal ions in the alkali liquor is controlled, the corrosion phenomenon of the electrolytic bath is reduced, and the stability and efficiency of the electrolytic process are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of alkaline water electrolysis, especially to a dissolubility regulator adding device. BACKGROUND

[0002] Alkaline water electrolysis (AWE) is a method of electrolyzing water into gaseous hydrogen and oxygen. It uses an electrolyte (currently potassium hydroxide KOH or sodium hydroxide NaOH, eventually possibly with some additives) as the alkaline solution. These ions participate in electrochemical reactions during electrolysis, helping to split water molecules into gaseous hydrogen and oxygen. The electrochemical reactions that take place inside the electrolyzer are divided into two steps:

[0003] (1) At the anode, hydroxide ions are consumed under the action of electrical energy, transforming into water molecules and oxygen, with the reaction formula 4OH⁻→O2+4e⁻+2H2O.

[0004] (2) At the cathode, water molecules are transformed into hydrogen and new hydroxide ions under the action of the same electrical energy, with the reaction formula 4H2O+4e⁻→2H2+4OH⁻.

[0005] Reference Figure 9 , the electrolyzer is a complex whole made of metals and conductive materials, its internal structure usually includes two bipolar plates 103, two separator plates 102 (also known as flow field material), two electrodes 101 (common forms are plates, grids or metal meshes) and a layer of membrane 100. The electrodes are usually made of nickel and separated by a separator, which not only achieves electrical insulation between the two electrodes, but also plays a key role in gas separation and ion conduction within the electrolytic cell. Other key components of the electrolyzer include the power distribution board 104, which provides and distributes power to the electrolyzer; the bottom plate 106, which defines the overall structure of the electrolyzer and ensures the tight sealing and water tightness of the electrolyzer through the gasket 105.

[0006] During the alkaline water electrolysis process, the working environment of the electrolyzer is extremely harsh, not only because it is exposed to extreme conditions of high temperature (usually between 70 and 85°C), high pressure and high oxygen concentration (especially in the anode area), which together constitute a highly challenging operating environment. In such an environment, the key structural components of the electrolyzer, including but not limited to the reactor, gas-liquid separator, circulating pump, etc., as well as the pipes connecting these components, are extremely susceptible to chemical corrosion. Corrosion can cause the release of metal ions (such as M²⁺), which circulate in the system and eventually contaminate the entire electrolyzer, affecting its performance and lifespan.

[0007] The corrosion process is a complex chain of chemical reactions that can be broken down into several key steps. First, gaseous oxygen adsorbs onto the surface of the electrolyzer structural metal (M). Subsequently, oxygen reacts with the metal (M) to form a layer of metal oxide, which gradually thickens to form a so-called passivation layer. Although the passivation layer slows the corrosion rate to some extent, it does not completely prevent the diffusion of oxygen, especially through small pores and cracks in the layer, which continues to react with the internal metal, releasing more metal ions.

[0008] Within the electrolyzer, specific electrochemical reactions occur in the anode region (oxygen-deficient zone) and the cathode region (oxygen-rich zone). Referring to Figure 10 , in the anode region, the metal loses electrons and is oxidized to metal ions (2M → 2M²⁺ + 4e⁻); in the cathode region, water molecules combine with oxygen and accept electrons to form hydroxide ions (2H2O + O2 + 4e⁻ → 4OH⁻). These reactions promote the further formation of metal oxides (2M²⁺ + 4OH⁻ → 2M(OH)2), which can also be converted into more complex oxides (4M(OH)2 + O2 → 2M2O3·H2O + 2H2O) in dry environments.

[0009] Traditional chemical reaction designs are often adapted to neutral, acidic, or even other diverse chemical environmental conditions. However, in alkaline environments, the distribution and existence form of chemical species change significantly according to the Pourbaix diagram due to the significant increase in the concentration of hydroxide ions. Specifically, certain chemical species exist in the form of cations in environments with low pH values, but when the pH value increases, they are more likely to be converted into anions and surrounded by oxides, hydroxides, or oxyhydroxides. Referring to Figure 11 , for example, iron cation species such as Fe²⁺ and Fe³⁺ gradually convert into anion species and ultimately form Fe(OH)³ in conditions with high pH values and high OH⁻ concentrations. - 2+ 3+ 4-

[0010] To effectively prevent corrosion, especially in the entire hydrogen production system, especially the structural components that come into direct contact with the electrolyte inside the electrolyzer, stainless steel or other high-performance materials are often used, and a layer of nickel protective layer is applied to the surface. The primary purpose is to provide better corrosion resistance. Therefore, the uniformity of the nickel protective layer is crucial as it maximizes the reduction of gaseous material leakage.

[0011] ​​​​However, some components in the electrolytic cell are not fully covered by the nickel protective layer. Especially for structural components that require cutting, welding, or coating, nickel plating is not the optimal choice due to the potential for defects at the joints during these processes, potentially leading to a higher risk of corrosion. For these more fragile structural components, high-quality stainless steel containing other elements (such as nickel and chromium) is recommended. For example, pipelines transporting liquid-gas mixtures from the reactor to gas-liquid separators, scrubbers, and other equipment. High-quality stainless steel can form a passivation layer mainly composed of different oxides, with a chemical principle similar to the transformation of iron ions (e.g., Cr2O3). In alkaline environments, the passivation layer formed by high-quality stainless steel has stronger corrosion resistance than that formed by conventional materials (such as Fe(OH)2). Nevertheless, this higher-quality passivation layer may still adsorb a small amount of weak hydroxide ions, causing some corrosion to the underlying metal (M). Therefore, metal ions (M) x+ Contamination will exist in a limited way throughout the electrolysis system.

[0012] In addition, applying a nickel coating to pipes or components made of high-quality stainless steel also has certain drawbacks, namely, it increases the overall cost of the electrolysis system.

[0013] In conclusion, neither nickel plating solutions nor higher-quality stainless steel can completely eliminate corrosion from the constituent elements of the electrolytic cell. This chemical corrosion process still exists, albeit to a degree controlled within a certain range. This continuous corrosion of the electrolytic cell can cause a series of problems during its operation and may adversely affect its service life. Once the constituent elements of the electrolytic cell (such as pipes, separation devices, etc.) are corroded, metal ions (M... x+ The ions (M) will circulate throughout the electrolysis system via the alkali solution and deposit at locations such as electrode 101 and membrane 100. x+ On the cathode side, it is reduced to the metallic (M) component (reaction formula is 2M). x+ +xe-→2M). In other words, metal ions (M x+ The metal ions are reduced to metal (M) and directly electrodeposited on the cathode surface. The chemical reaction of metal ion reduction occurs simultaneously with the chemical reaction that produces gaseous hydrogen. Over time, the cathode is gradually covered with metal (M), which initially originates from metal ions (M) generated during corrosion. x+ The active sites on the cathode surface, originally intended for hydrogen production, are gradually covered by the metal (M), thus losing accessibility and activity in the water electrolysis reaction. Ultimately, the performance of the entire electrolysis system deteriorates as a result.

[0014] To solve at least one of the above-mentioned technical problems, this application proposes a device for adding a solubility regulator. Summary of the Invention

[0015] The purpose of this invention is to provide a solubility regulator addition device, which can add the solubility regulator to the electrolytic cell to help reduce the solubility of metal ions in the alkaline solution, thereby controlling the concentration of metal ions in the alkaline solution, reducing corrosion of the electrolytic cell, and improving the stability and efficiency of the electrolysis process.

[0016] The objective of this utility model is achieved through the following technical solution:

[0017] This utility model provides a solubility regulator addition device, which is applied to an electrolytic cell. The electrolytic cell includes a reactor, a pipeline assembly, a hydrogen gas-liquid separator, an oxygen gas-liquid separator, and an alkali solution pumping assembly. The pipeline assembly connects the reactor, the hydrogen gas-liquid separator, the oxygen gas-liquid separator, and the alkali solution pumping assembly.

[0018] The adding device includes at least one set of adding components, each adding component including:

[0019] Storage unit for storing solubility modifiers;

[0020] An addition valve is provided, with its first end connected to the storage unit and its second end connected to the piping assembly, hydrogen gas-liquid separator, oxygen gas-liquid separator, or alkali pump inlet assembly.

[0021] Furthermore, the added components also include:

[0022] An additive pump, disposed between the storage unit and the additive valve, is used to pump the solubility modifier into the alkaline solution of the electrolytic cell.

[0023] Furthermore, the added pump is a one-way pump.

[0024] Furthermore, the alkali pumping assembly includes:

[0025] An alkali storage unit, wherein the alkali storage unit is used to store the alkali solution;

[0026] An alkali injection valve, the first end of which is connected to the alkali storage unit, and the second end of which is connected to the reactor, the hydrogen gas-liquid separator, and / or the oxygen gas-liquid separator;

[0027] An alkali injection pump is disposed between the alkali injection valve and the alkali storage unit.

[0028] Furthermore, the adding valve is connected to the alkali storage unit;

[0029] The addition pump is used to pump the solubility regulator into the alkali solution in the alkali storage unit.

[0030] Furthermore, the adding device includes a second adding component;

[0031] The first addition valve of the first addition component is connected to the oxygen gas-liquid separator, and the first addition pump of the first addition component is used to pump the solubility regulator into the alkaline solution of the oxygen gas-liquid separator.

[0032] The second addition valve of the second addition component is connected to the hydrogen gas-liquid separator, and the second addition pump of the second addition component is used to pump the solubility regulator into the alkaline solution of the hydrogen gas-liquid separator.

[0033] Furthermore, the adding device includes a first adding component;

[0034] The first addition valve of the first addition component is connected to the oxygen gas-liquid separator, and the first addition pump of the first addition component pumps a solubility modifier into the alkaline solution of the oxygen gas-liquid separator. Further, the first addition valve of the first addition component is connected to the liquid phase of the oxygen gas-liquid separator.

[0035] The second addition valve of the second addition component is connected to the liquid phase of the hydrogen gas-liquid separator.

[0036] Furthermore, the piping assembly includes:

[0037] A first pipeline, the first end of which is connected to the second gas-liquid outlet of the reactor, and the second end of which is connected to the second gas-liquid inlet of the oxygen gas-liquid separator;

[0038] The second pipeline has a first end connected to the first gas-liquid outlet of the reactor and a second end connected to the first gas-liquid inlet of the hydrogen gas-liquid separator.

[0039] The third pipeline has its first end connected to the second drain port of the hydrogen gas-liquid separator and its second end connected to the alkaline inlet of the reactor.

[0040] The fourth pipeline has its first end connected to the first drain port of the oxygen gas-liquid separator and its second end connected to the alkaline inlet of the reactor.

[0041] The sixth pipeline has its first end connected to the alkaline inlet of the reactor, and its second end connected to the second end of the third pipeline and the second end of the fourth pipeline.

[0042] Furthermore, the addition valve is connected to the second, third, fourth, and / or sixth pipelines, and the addition pump is used to pump the solubility regulator into the alkaline solution in the second, third, fourth, and / or sixth pipelines.

[0043] Furthermore, the adding device includes a first adding component and a second adding component;

[0044] The first addition valve of the first addition component is connected to the first pipeline, and the first addition pump of the first addition component is used to pump the solubility modifier into the alkaline solution in the first pipeline.

[0045] The second addition valve of the second addition component is connected to the second pipeline, and the second addition pump of the second addition component is used to pump the solubility regulator into the alkaline solution in the second pipeline.

[0046] Furthermore, the electrolytic cell includes a circulation pump, which is mounted on the piping assembly.

[0047] Furthermore, the piping assembly includes:

[0048] The fifth pipeline has its first end connected to the second cylinder of the liquid phase of the hydrogen gas-liquid separator, and its second end connected to the first cylinder of the liquid phase of the oxygen gas-liquid separator. The fifth pipeline is a balance pipeline.

[0049] Compared with the prior art, the beneficial effects of this utility model include at least the following:

[0050] The addition device of this invention can add solubility regulator to the alkaline solution of the electrolytic cell to control the concentration of metal ions in the alkaline solution, reduce the risk of corrosion and pollution of the electrolytic cell, and improve the stability and efficiency of the electrolysis process. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the structure of the adding device according to an embodiment of the present utility model.

[0052] Figure 2 This is another structural schematic diagram of the adding device according to an embodiment of the present utility model.

[0053] Figure 3 This is another structural schematic diagram of the adding device according to an embodiment of the present utility model.

[0054] Figure 4 This is another structural schematic diagram of the adding device according to an embodiment of the present utility model.

[0055] Figure 5 This is another structural schematic diagram of the adding device according to an embodiment of the present utility model.

[0056] Figure 6 This is another structural schematic diagram of the adding device according to an embodiment of the present utility model.

[0057] Figure 7 This is another structural schematic diagram of the adding device according to an embodiment of the present utility model.

[0058] Figure 8 This is another structural schematic diagram of the adding device according to an embodiment of the present utility model.

[0059] Figure 9 This is a schematic diagram of a reactor structure based on existing technology.

[0060] Figure 10 This is a schematic diagram of a chemical reaction that occurs in a metal structure in an existing electrolytic cell.

[0061] Figure 11 This is a schematic diagram showing the relationship between different oxidation states of iron and pH value.

[0062] In the diagram: 1. Reactor; 100. Membrane; 101. Electrode; 102. Separator; 103. Bipolar plate; 104. Power distribution board; 106. Base plate; 105. Gasket; 2. Hydrogen gas-liquid separator; 21. First gas-liquid inlet; 22. Second drain outlet; 23. Second liquid phase; 24. Second exhaust outlet; 3. Oxygen gas-liquid separator; 31. Second gas-liquid inlet; 32. First drain outlet; 33. First liquid phase; 34. First exhaust outlet; 4. Alkali pump inlet assembly; 41. Alkali storage unit; 42. Alkali injection pump; 43. Alkali injection valve; 50. Addition assembly; 501, Storage unit; 502, Addition pump; 503, Addition valve; 51, First addition assembly; 511, First storage unit; 512, First addition pump; 513, First addition valve; 52, Second addition assembly; 521, Second storage unit; 522, Second addition pump; 523, Second addition valve; 6, Piping assembly; 61, First pipeline; 62, Second pipeline; 63, Third pipeline; 64, Fourth pipeline; 65, Fifth pipeline; 66, Sixth pipeline; 7, Circulation pump; 91, Oxygen storage unit; 92, Hydrogen storage unit, M is metal. Detailed Implementation

[0063] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the present invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore repeated descriptions of them will be omitted.

[0064] The terms used to describe position and direction in this utility model are illustrated with the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of this utility model.

[0065] In order to accurately add solubility regulators to the alkaline solution of the electrolytic cell and effectively control the concentration of metal ions in the alkaline solution, the addition device of this invention is used to add solubility regulators to the electrolytic cell.

[0066] The electrolyzer includes: a reactor 1, an alkali pumping assembly 4, a hydrogen gas-liquid separator 2, an oxygen gas-liquid separator 3, a piping assembly 6, and a circulation pump 7. Further, the electrolysis unit may also include: an alkali pumping out assembly, a hydrogen storage unit 92, and an oxygen storage unit 91. Specifically, the piping assembly 6 connects the reactor 1, the alkali pumping in assembly 4, the alkali pumping out assembly, the hydrogen gas-liquid separator 2, and the oxygen gas-liquid separator 3, and the circulation pump 7 is installed on the piping assembly 6 to achieve liquid circulation within the piping assembly 6.

[0067] The alkali injection assembly 4 includes an alkali storage unit 41, an alkali injection pump 42, and an alkali injection valve 43 connected in sequence. The alkali storage unit 41 is used to store alkali. The second end of the alkali injection valve 43 is connected to the reactor 1, the hydrogen gas-liquid separator 2, and / or the oxygen gas-liquid separator 3 to pump the alkali into the pipeline assembly 6. In application, the alkali injection valve 43 is connected to the alkali inlet of the reactor 1. Opening the alkali injection valve 43 starts the alkali injection pump 42 to pump the alkali into the reactor 1 to participate in the electrolysis reaction.

[0068] The alkali inlet assembly 4 is reused as an alkali outlet assembly for alkali recovery, reducing the use of components. In application, the alkali injection pump 42 is a bidirectional pump; specifically, bidirectional liquid transport can be achieved by changing the rotation direction of the centrifugal pump impeller. In practical applications, the alkali injection valve 43 is opened, and the alkali injection pump 42 is started to pump the alkali in the pipeline assembly 6 into the alkali storage unit 41, avoiding environmental pollution and resource waste.

[0069] Reactor 1 comprises multiple reaction pools for electrolyzing water to generate hydrogen and oxygen. The first gas-liquid inlet 21 of the hydrogen gas-liquid separator 2 is connected to the first gas-liquid outlet of reactor 1, and the second gas-liquid inlet 31 of the oxygen gas-liquid separator 3 is connected to the second gas-liquid outlet of reactor 1. Further, the first mixture flowing into the first gas-liquid inlet 21 from the first gas-liquid outlet includes hydrogen and alkaline solution, which will be separated into alkaline solution and hydrogen inside the hydrogen gas-liquid separator 2. The second mixture flowing into the second gas-liquid inlet 31 from the second gas-liquid outlet includes oxygen and alkaline solution, which will be separated into alkaline solution and oxygen inside the oxygen gas-liquid separator 3.

[0070] In this invention, the second exhaust port 24 of the hydrogen gas-liquid separator 2 is connected to the hydrogen storage unit 92, and the first exhaust port 34 of the oxygen gas-liquid separator 3 is connected to the oxygen storage unit 91. The second drain port 22 of the hydrogen gas-liquid separator 2 and the first drain port 32 of the oxygen gas-liquid separator 3 are connected to the alkaline solution pumping assembly. In application, the gaseous oxygen discharged from the first exhaust port 34 needs further purification (e.g., filtration) before being stored in the oxygen storage unit 91, and the gaseous hydrogen discharged from the second exhaust port 24 also needs further purification (e.g., filtration) before being stored in the hydrogen storage unit 92. The piping assembly 6 includes: a first pipe 61, a second pipe 62, a third pipe 63, a fourth pipe 64, a fifth pipe 65, and a sixth pipe 66. Specifically, the first end of the first pipe 61 is connected to the second gas-liquid outlet of reactor 1, and the second end of the first pipe 61 is connected to the second gas-liquid inlet 31 of oxygen gas-liquid separator 3; the first end of the second pipe 62 is connected to the first gas-liquid outlet of reactor 1, and the second end of the second pipe 62 is connected to the first gas-liquid inlet 21 of hydrogen gas-liquid separator 2; the first end of the third pipe 63 is connected to the second drain port 22 of hydrogen gas-liquid separator 2, and the second end of the third pipe 63 is connected to the alkaline inlet of reactor 1; the first end of the fourth pipe 64 is connected to oxygen... The first drain port 32 of the gas-liquid separator 3 and the second end of the fourth pipeline 64 are connected to the alkaline inlet of the reactor 1; the first end of the sixth pipeline 66 is connected to the alkaline inlet of the reactor 1, and the second end of the sixth pipeline 66 is connected to the second end of the third pipeline 63 and the second end of the fourth pipeline 64; the fifth pipeline 65 is a balancing pipeline: the first end of the fifth pipeline 65 is connected to the second cylinder (not shown) of the liquid phase of the hydrogen gas-liquid separator 2, and the second end of the fifth pipeline 65 is connected to the first cylinder (not shown) of the liquid phase of the oxygen gas-liquid separator 3. Preferably, the first end of the fifth pipeline 65 is connected to the second liquid phase 23 of the second cylinder of the liquid phase, and the second end of the fifth pipeline 65 is connected to the first liquid phase 33 of the first cylinder of the liquid phase.

[0071] refer to Figures 1-8 The addition device of this utility model includes at least one set of addition components 50, each addition component 50 including: a storage unit 501, an addition pump 502, and an addition valve 503 connected in sequence. Specifically, the storage unit 501 is used to store the solubility regulator, and the second end of the addition valve 503 is connected to the pipeline assembly 6, the hydrogen gas-liquid separator 2, the oxygen gas-liquid separator 3, or the alkaline solution pumping assembly 4. The addition pump 502 pumps the solubility regulator into the alkaline solution in the electrolytic cell. In application, the addition pump 502 is a one-way pump, and the addition valve 503 is a one-way valve, ensuring that the solubility regulator can only flow in one direction, avoiding the risk of backflow and contamination.

[0072] refer to Figure 3In some embodiments, the addition valve 503 of this invention is connected to the sixth pipeline 66, and the addition pump 502 is used to pump the solubility regulator into the alkaline solution in the sixth pipeline 66.

[0073] refer to Figure 1 In other embodiments, the addition valve 503 of this invention is connected to the alkali storage unit 41 to pump the solubility regulator into the alkali solution in the alkali storage unit 41. This allows the solubility regulator to be added directly during the alkali solution pumping stage, improving the efficiency and flexibility of the addition. In application, before injecting the alkali solution into the electrolytic cell, the addition valve 503 and the addition pump 502 are opened. The addition pump 502 pumps the solubility regulator into the alkali solution in the alkali storage unit 41 and mixes it evenly with the alkali solution. Then, the addition valve 503 and the addition pump 502 are closed, and the alkali injection valve 43 and the alkali injection pump 42 are opened to pump the alkali solution containing the solubility regulator into the reactor 1. This reduces the solubility of metal ions in the alkali solution at the start of system operation, thereby slowing down the corrosion of the electrolytic cell.

[0074] refer to Figure 6 In other embodiments, the addition valve 503 of this invention is connected to a third pipeline 63, and the addition pump 502 is used to pump the solubility regulator into the alkaline solution in the third pipeline 63.

[0075] refer to Figure 7 In other embodiments, the addition valve 503 of this invention is connected to a fourth pipeline 64, and the addition pump 502 is used to pump the solubility regulator into the alkaline solution in the fourth pipeline 64.

[0076] refer to Figure 8 In some other embodiments, the present invention provides at least two sets of adding components 50. One set of adding components 50 has an adding valve 503 connected to a third pipeline 63, and an adding pump 502 to pump the solubility regulator into the alkaline solution in the third pipeline 63; the other set of adding components 50 has an adding valve 503 connected to a fourth pipeline 64, and an adding pump 502 to pump the solubility regulator into the alkaline solution in the fourth pipeline 64.

[0077] refer to Figure 5 In other embodiments, the addition valve 503 of this invention is connected to the second pipeline 62, and the addition pump 502 is used to pump the solubility regulator into the alkaline solution connected to the second pipeline 62.

[0078] refer to Figure 4In some embodiments, the addition device of this invention includes a first addition component 51 and a second addition component 52. Specifically, the first addition component 51 includes a first storage unit 511, a first addition pump 512, and a first addition valve 513 connected in sequence. The second addition component 52 includes a second storage unit 521, a second addition pump 522, and a second addition valve 523 connected in sequence. In application, both the first addition pump 512 and the second addition pump 522 are one-way pumps, and both the first addition valve 513 and the second addition valve 523 are one-way valves. In practical application, the first addition valve 513 of this invention is connected to the first pipeline 61, and the first addition pump 512 pumps the solubility regulator into the alkaline solution in the first pipeline 61; the second addition valve 523 is connected to the second pipeline 62, and the second addition pump 522 pumps the solubility regulator into the alkaline solution in the second pipeline 62. Preferably, the first addition component 51 and the second addition component 52 are identical structural components.

[0079] refer to Figure 2 In some other preferred embodiments, to add solubility regulators separately to the oxygen gas-liquid separator 3 and the hydrogen gas-liquid separator 2, and to achieve precise control over different parts of the electrolysis process, the addition device of this invention includes a first addition component 51 and a second addition component 52. Specifically, the first addition valve 513 is connected to the oxygen gas-liquid separator 3, and the first addition pump 512 pumps the solubility regulator into the alkaline solution of the oxygen gas-liquid separator 3; the second addition valve 523 is connected to the hydrogen gas-liquid separator 2, and the second addition pump 522 pumps the solubility regulator into the alkaline solution of the hydrogen gas-liquid separator 2. In application, to ensure that the solubility regulator can directly act on the liquid phase alkaline solution and improve the adjustment effect, the first addition valve 513 is connected to the liquid phase of the oxygen gas-liquid separator 3, and the second addition valve 523 is connected to the liquid phase of the hydrogen gas-liquid separator 2. Preferably, the first addition component 51 and the second addition component 52 are identical structural components.

[0080] During electrolysis, the metals used in the structural components and pipes of the electrolytic cell are prone to chemical corrosion. If this corrosion is not controlled, it can lead to severe erosion of the pipes or structural components inside the electrolytic cell, causing cracks, leaks, and other safety hazards, threatening the lives of on-site operators and the integrity of the equipment. Traditional corrosion inhibitors, such as ammonia compounds, often face two major challenges during electrolysis: first, they may react chemically on the electrodes and be consumed, thus losing their corrosion-inhibiting effect; second, they may adsorb onto the electrode surface, blocking active sites and reducing the efficiency of the electrolytic cell.

[0081] Corroded structural components release metal ions M throughout the system. x+ This contaminates the entire electrolytic cell. The chemical reaction of chemical corrosion includes steps A1-A3, see reference... Figure 10 :

[0082] Step A1: Oxygen is present in the electrolysis system and is adsorbed on the surface of the metal M component in the electrolytic cell.

[0083] Step A2: Oxygen and metal are added to form a metal oxide, which begins to grow in multiple directions. At the same time, oxygen is continuously adsorbed into the metal component M.

[0084] Step A3: As oxygen is continuously adsorbed, the metal oxide layer grows larger, eventually forming a passivation layer on the surface of the metal M component. The passivation layer still allows oxygen to diffuse into the metal M component through cavities and micro / macro pores, thereby continuously releasing metal ions M within the electrolytic cell. x+ .

[0085] Metal ion M x+ When dissolved in alkaline solution, it tends to be widely distributed throughout the electrolytic cell in the form of hydroxides, oxides, or oxyhydroxides; that is, it mainly exists as oxides under alkaline conditions. To prevent metal ions M... x+ Accumulation in an alkaline environment reduces the risk of equipment corrosion and pollution, and improves the stability and efficiency of the electrolysis process. This utility model proposes a method, a solubility regulator and an addition device for reducing the degree of corrosion of electrolytic cells.

[0086] The solubility regulator of this invention is used to reduce the solubility of metal ions M. x+ Solubility in alkaline solutions. Metal ion M x + The metal M component originates from the alkaline solution dissolved in the alkaline solution during the alkaline water electrolysis process in the electrolytic cell. Electrolytic cells are typically made of stainless steel or steel with a nickel protective coating. Stainless steel, a common corrosion-resistant material, contains various metallic elements, such as chromium (Cr) and iron (Fe). Therefore, the metal ions M... x+ Including iron III ions, iron II ions, chromium ions, and other metal ions. The electrolytic cell is made of stainless steel; metal ions M x+ This includes iron III ions and / or iron II ions. Further, metal ions M... x+ It may also include chromium ions.

[0087] Solubility modifiers do not participate in the reaction during the electrolysis of alkaline water. Solubility modifiers include combinations of one or more hydroxides (XOH), where the cations of the hydroxides originate from elements in Group IA or Group IIA of the periodic table. For example, a solubility modifier may be an aqueous solution of one or more of the following: lithium hydroxide (LiOH), sodium hydroxide (NaOH), potassium hydroxide (KOH), rubidium hydroxide (RbOH), cesium hydroxide (CsOH), francium hydroxide (FrOH), beryllium hydroxide (Be(OH)2), magnesium hydroxide (Mg(OH)2), calcium hydroxide (Ca(OH)2), strontium hydroxide (Sr(OH)2), barium hydroxide (Ba(OH)2), or radium hydroxide (Ra(OH)2).

[0088] Solubility regulators are activated by hydroxyl anions (OH-). - With cation X + The binding reaction of metal ions causes them to dissolve in alkaline solutions. x+ The solubility is directly affected by the cation concentration X in the solubility regulator. + The effect of M in the solution. When the solubility of metal ions in alkaline solution reaches the saturation point, due to the presence of M in the solution... x+ With the reduction of [something], step A3 in the corrosion process will be significantly slowed down.

[0089] In an alkaline environment without a solubility modifier, a porous passivation layer easily forms on the surface of metal oxides. This porous passivation layer continuously adsorbs gaseous oxygen, promoting the formation of metal ions M x+ The continuous release of metal ions from the substrate (M) into the electrolytic cell leads to severe metal corrosion. However, after adding a solubility modifier, the maximum solubility of metal ions in the alkaline solution is significantly reduced, rapidly reaching saturation. This effectively prevents the diffusion of additional metal ions from the metal substrate into the alkaline solution, thus achieving a balance and mitigation of the corrosion process. At this point, no more metal ions penetrate to the outer surface of the porous passivation layer of the metal oxide, and the corrosion phenomenon is significantly suppressed. It is evident that the solubility modifier's ability to alter the corrosion balance by regulating the solubility of metal ions is a cationic effect.

[0090] Furthermore, solubility modifiers can also directly participate in the construction of metal oxide passivation layers. During electrolytic cell startup, the solubility modifier enters the system along with the alkaline solution, not only slowing down the corrosion rate, but also... (The sentence is incomplete and requires further context to translate accurately.) + It can also be embedded in the porous structure of metal oxides, specifically including the following steps:

[0091] Step B1a: Gaseous oxygen is adsorbed on the surface of the metal M component in the electrolysis system.

[0092] Step B1b: In the presence of hydroxide ions (OH-) - and cation X +Under the combined action of these factors, the solubility regulator dissolves in the alkaline solution.

[0093] Step B2: Gaseous oxygen, metal M, and cation X + The interaction forms a metal oxide layer, which grows and expands outwards. The metal oxide layer contains components from both the metal substrate and the solubility modifier.

[0094] Step B3: With the continuous adsorption of gaseous oxygen, the metal oxide layer gradually thickens, eventually forming a modified passivation layer with stronger corrosion resistance on the metal surface. The modified passivation layer comprises the metal component M and the cationic X from the solubility modifier. + This effectively prevents the alkaline solution from corroding the metal substrate. Although trace amounts of hydroxide ions can still penetrate the modified passivation layer, causing slow corrosion of the metal, overall, the metal ion M... x+ The spread of contaminants in the electrolysis system was greatly limited.

[0095] The solubility regulator in the alkaline solution of this invention has a weight percentage of 0.1~15wt%, for example: 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1.0wt%, 2.0wt%, 3.0wt%, 4.0wt%, 5.0wt%, 6.0wt%, 7.0wt%, 80.0wt%, 9.0wt%, 10.0wt%, 11.0wt%, 12.0wt%, 13.0wt%, 14.0wt%, or 15.0wt%. Preferably, the solubility regulator in the alkaline solution has a weight percentage of 0.1~5wt%, for example: 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1.0wt%, 2.0wt%, 3.0wt%, 4.0wt%, or 5.0wt%.

[0096] To make the objectives, technical solutions, and advantages of this utility model clearer, Examples 1-4 and Comparative Example 1 are provided for further detailed explanation. Specifically, the parameters and adjustment effects of the solubility regulators in Examples 1-4 and Comparative Example 1 are detailed in Tables 1 and 2. In the tables, metal ions include iron III ions and iron II ions. It should be understood that the specific embodiments described herein are merely illustrative of this utility model and are not intended to limit it.

[0097]

[0098]

[0099] In summary, current mainstream electrolytic cells often require nickel-coated pipes or high-quality stainless steel components to ensure corrosion resistance. While high-performance materials do effectively resist corrosion, they significantly increase procurement costs. By using solubility modifiers, the solubility of metal ions in alkaline solutions can be significantly reduced, or a more robust modified passivation layer can be formed on metal structural components, effectively inhibiting the corrosion process. This makes it possible to use more cost-effective materials, such as carbon steel, thereby significantly reducing the production cost of electrolytic cells.

[0100] Furthermore, in traditional electrolysis, metal ions are reduced to metal M in the cathode region, i.e., electrodeposition occurs (2M). x+ The process of +xe-→2M often leads to the gradual accumulation of metal deposits on the cathode surface. However, by using solubility modifiers, the deposition of metal ions on the electrode surface is effectively limited, ensuring that the active sites of the electrode are not blocked or covered by metal coatings generated by corrosion. This greatly reduces the degradation of system performance caused by corrosion contamination and significantly improves the durability and long-term operating efficiency of the electrolytic cell.

[0101] In order to effectively reduce the concentration of metal ions in the alkaline solution, thereby reducing corrosion of the electrolytic cell, extending its service life, and improving production efficiency, the method of this utility model for reducing the degree of corrosion of the electrolytic cell includes the following steps:

[0102] SS10: Open the addition valve 503 and the addition pump 502 to pump the solubility regulator into the alkaline solution in the alkaline solution pumping component 4, mix it with the alkaline solution, and pump the alkaline solution containing the solubility regulator into the electrolytic cell.

[0103] In application, the solubility regulator can be a single hydroxide class, such as lithium hydroxide. The solubility regulator can also be a mixture containing multiple hydroxides. Furthermore, by adjusting the concentration of the solubility regulator within the range of 0.1 wt% to 15 wt%, its effectiveness in alkaline solutions is optimized while avoiding unnecessary waste or side effects.

[0104] In practical applications, step SS10 can be omitted.

[0105] SS11: Add the solubility modifier to the storage unit 501 of the addition device.

[0106] SS12: Detects the concentration of metal ions in alkaline solutions.

[0107] When applied, the methods for determining the content of dissolved metal ions in alkaline solutions include, but are not limited to, ultraviolet-visible spectroscopy, atomic absorption spectrometry (AAS), inductively coupled plasma mass spectrometry (ICP), and liquid chromatography.

[0108] SS13: When the concentration of metal ions is greater than or equal to the preset concentration, open the addition valve 503 and the addition pump 502 to pump the solubility regulator into the alkaline solution of the electrolytic cell.

[0109] If step SS10 is not performed during application, the risk of corrosion increases significantly during the initial operation of the electrolytic cell after the alkali solution has entered circulation, as an effective modified passivation layer has not yet formed on the surfaces of pipes and structural components. Therefore, a solubility regulator should be introduced immediately at the initial stage of equipment startup to effectively inhibit corrosion.

[0110] In practical applications, the specific locations for adding solubility modifiers within the electrolytic cell are varied, including but not limited to the vicinity of the alkali injection pump 42, between the gas-liquid separator and the alkali injection pump 42, and between the alkali injection pump 42 and the reactor 1. Furthermore, solubility modifiers can also be added inside the gas-liquid separator or between the reactor 1 and the gas-liquid separator.

[0111] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and alterations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention, and all such changes should fall within the protection scope of the claims of the present invention.

Claims

1. A device for adding a solubility regulator, characterized in that, The addition device is applied to an electrolytic cell, which includes a reactor (1), a pipeline assembly (6), a hydrogen gas-liquid separator (2), an oxygen gas-liquid separator (3), and an alkali pumping assembly (4). The pipeline assembly (6) connects the reactor (1), the hydrogen gas-liquid separator (2), the oxygen gas-liquid separator (3), and the alkali pumping assembly (4). The adding device includes at least one set of adding components (50), each adding component (50) including: Storage unit (501) for storing solubility modifier; Add valve (503), the first end of which is connected to the storage unit (501), and the second end of which is connected to the pipeline assembly (6), hydrogen gas-liquid separator (2), oxygen gas-liquid separator (3) or alkali pump inlet assembly (4).

2. The device for adding the solubility regulator according to claim 1, characterized in that, The added component (50) also includes: An additive pump (502) is disposed between the storage unit (501) and the additive valve (503) to pump a solubility regulator into the alkaline solution of the electrolytic cell.

3. The device for adding the solubility regulator according to claim 2, characterized in that, The alkali pumping assembly (4) includes: Alkali storage unit (41), the alkali storage unit (41) is used to store the alkali solution; Alkali injection valve (43), the first end of which is connected to the alkali storage unit (41), and the second end of which is connected to the reactor (1), the hydrogen gas-liquid separator (2) and / or the oxygen gas-liquid separator (3). An alkali injection pump (42) is disposed between the alkali injection valve (43) and the alkali storage unit (41).

4. The device for adding the solubility regulator according to claim 3, characterized in that, The addition valve (503) is connected to the alkali storage unit (41). The addition pump (502) pumps the solubility regulator into the alkali solution in the alkali storage unit (41).

5. The device for adding the solubility regulator according to claim 1, characterized in that, The adding device includes a second adding component (52); The second addition valve (523) of the second addition component (52) is connected to the hydrogen gas-liquid separator (2), and the second addition pump (522) of the second addition component (52) pumps the solubility regulator into the alkaline solution of the hydrogen gas-liquid separator (2).

6. The device for adding the solubility regulator according to claim 5, characterized in that, The adding device includes a first adding component (51); The first addition valve (513) of the first addition component (51) is connected to the oxygen gas-liquid separator (3), and the first addition pump (512) of the first addition component (51) pumps the solubility regulator into the alkaline solution of the oxygen gas-liquid separator (3).

7. The device for adding a solubility regulator according to claim 6, characterized in that, The first addition valve (513) of the first addition component (51) is connected to the liquid phase of the oxygen gas-liquid separator (3); The second addition valve (523) of the second addition component (52) is connected to the liquid phase of the hydrogen gas-liquid separator (2).

8. The device for adding the solubility regulator according to claim 2, characterized in that, The piping assembly (6) includes: The first pipeline (61) has its first end connected to the second gas-liquid outlet of the reactor (1) and its second end connected to the second gas-liquid inlet (31) of the oxygen gas-liquid separator (3). The second pipeline (62) has its first end connected to the first gas-liquid outlet of the reactor (1) and its second end connected to the first gas-liquid inlet (21) of the hydrogen gas-liquid separator (2). The third pipeline (63) has its first end connected to the second drain port (22) of the hydrogen gas-liquid separator (2) and its second end connected to the alkaline inlet of the reactor (1). The fourth pipeline (64) has its first end connected to the first drain port (32) of the oxygen gas-liquid separator (3) and its second end connected to the alkaline inlet of the reactor (1). The sixth pipeline (66) has its first end connected to the alkaline inlet of the reactor (1), and its second end connected to the second end of the third pipeline (63) and the second end of the fourth pipeline (64).

9. The device for adding a solubility regulator according to claim 8, characterized in that, The addition valve (503) is connected to the second pipeline (62), the third pipeline (63), the fourth pipeline (64) and / or the sixth pipeline (66), and the addition pump (502) pumps the solubility regulator into the alkaline solution in the second pipeline (62), the third pipeline (63), the fourth pipeline (64) and / or the sixth pipeline (66).

10. The apparatus for adding a solubility regulator according to claim 8, characterized in that, The adding device includes a first adding component (51) and a second adding component (52); The first addition valve (513) of the first addition component (51) is connected to the first pipeline (61), and the first addition pump (512) of the first addition component (51) pumps the solubility regulator into the alkaline solution of the first pipeline (61). The second addition valve (523) of the second addition component (52) is connected to the second pipeline (62), and the second addition pump (522) of the second addition component (52) pumps the solubility regulator into the alkali solution of the second pipeline (62).

11. The device for adding the solubility regulator according to claim 1, characterized in that, The electrolytic cell includes a circulation pump (7), which is mounted on the pipeline assembly (6).

12. The device for adding the solubility regulator according to claim 1, characterized in that, The piping assembly (6) includes: The fifth pipeline (65) has its first end connected to the second cylinder of the liquid phase of the hydrogen gas-liquid separator (2) and its second end connected to the first cylinder of the liquid phase of the oxygen gas-liquid separator (3). The fifth pipeline (65) is a balance pipeline.

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