Electrolysis device

Abstract

The utility model discloses an electrolysis device. The electrolysis device integrates a reactor, a hydrogen gas-liquid separator, an oxygen gas-liquid separator and a cleaning assembly, and the cleaning assembly is connected with the reactor, the hydrogen gas-liquid separator and / or the oxygen gas-liquid separator and used for storing the cleaning agent for pickling. And the cleaning agent is provided for the electrolysis device during pickling, so that the pickling operation can be efficiently carried out, and the production efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of alkaline water electrolysis technology, and in particular to an electrolysis device. Background Technology

[0002] Alkaline water electrolysis (AWE) is a method for electrolytic hydrogen production that uses an electrolyte (currently potassium hydroxide KOH or sodium hydroxide NaOH, with the possibility of future additives) as an alkaline solution. The alkaline solution provides abundant OH-. - Ions, which participate in the electrochemical reactions during electrolysis, help electrolyze water molecules into hydrogen and oxygen. The electrochemical reactions occurring inside the electrolyzer consist of two steps:

[0003] (1) At the anode, hydroxide ions (OH-) are consumed by electrical energy and converted into water molecules and oxygen. The reaction formula is 4OH-. - →O2+4e - +2H2O.

[0004] (2) At the cathode, water molecules are converted into hydrogen gas (H2) and new hydroxide ions (OH-) under the same electrical energy. - The reaction is 4H₂O + 4e⁻. - →2H₂ + 4OH⁻ - .

[0005] refer to Figure 9 An electrolytic cell, as a complex unit composed of metals and conductive materials, typically includes two bipolar plates 103, two partition plates 102 (also known as flow field materials), two electrodes 101 (currently commonly in the form of plates, grids, or metal mesh), and a membrane 100. The electrodes are usually made of nickel and separated by a membrane, which not only provides electrical insulation between the two electrodes but also plays a crucial role in gas separation and ion conduction within the electrolytic cell. Other key components of the electrolytic cell include a power distribution plate 104, used to provide and distribute power to the cell; and a base plate 106, used to define the overall structure of the electrolytic cell and to ensure its tight sealing and watertightness via gaskets 105.

[0006] In alkaline water electrolysis, the electrolyzer operates in an extremely harsh environment, exposed to high temperatures (typically between 70 and 85°C), high pressures, and high oxygen concentrations (especially in the anode region). These conditions collectively create 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, and the piping connecting these components, are highly susceptible to chemical corrosion. Corrosion leads to the formation of metal ions (such as M... 2The release of ions (+) causes these ions to circulate in the system, eventually contaminating the entire electrolyzer and affecting its performance and lifespan.

[0007] The corrosion process is a complex chemical reaction chain, which can be divided into several key steps. First, gaseous oxygen (O2(g)) is adsorbed on the surface of the electrolytic cell's structural metal (M). Subsequently, the oxygen reacts with the metal to form a metal oxide layer (O). This oxide layer gradually thickens, forming what is known as a passivation layer. Although the passivation layer can slow down the corrosion rate to some extent, it cannot completely prevent the diffusion of oxygen, especially through tiny pores and cracks, allowing it to continue reacting with the internal metal and releasing more metal ions.

[0008] Inside the electrolytic cell, specific electrochemical reactions occur in the anode region (oxygen-deficient zone) and the cathode region (oxygen-rich zone). (Reference) Figure 10 In the anodic region, the metal loses electrons and is oxidized into metal ions (2M→2M). 2+ +4e - In the cathode region, water molecules combine with oxygen and accept electrons to generate hydroxide ions (2H₂O + O₂ + 4e⁻). - →4OH - These reactions promote the further formation of metal oxides (2M). 2+ +4OH - →2M(OH)2), and in a dry environment, it may also be transformed into more complex oxides (4M(OH)2+O2→2M2O3·H2O+2H2O).

[0009] To combat corrosion, components in the electrolytic cell that come into direct contact with the alkaline solution are often made of stainless steel or other corrosion-resistant materials and coated with a nickel protective layer (electrolytic nickel plating or electroless nickel plating) to improve corrosion resistance and prevent hydrogen / oxygen leakage. However, for components that require machining (such as cutting or welding), nickel plating may not be the best choice, as these operations can lead to plating defects and increase the risk of corrosion. For these components, using high-quality stainless steel rich in inert elements (such as nickel and chromium) is a better option, as they form a more stable passivation layer, such as Cr2O3, which has higher corrosion resistance than common iron oxides (such as Fe(OH)2).

[0010] Nevertheless, even high-quality stainless steel and nickel coatings cannot completely eliminate corrosion; they only slow down the corrosion rate. As corrosion progresses, metal ions circulate throughout the electrolysis system, eventually being reduced to metal at the cathode and deposited, covering active sites, clogging the diaphragm, or obstructing proper liquid / gas circulation within the system, leading to a decrease in electrolysis efficiency.

[0011] To restore the performance of the electrolytic cell, regular pickling is necessary. Using a weak acid (such as citric acid C6H8O7) can dissolve and remove deposited metal particles from the surface, leaving a surface rich in inert components. After pickling, the stainless steel oxidizes naturally in the air, forming a thicker, more protective layer of noble metal oxides, reducing the risk of future corrosion. However, oxygen can still penetrate this protective film and oxidize the metal beneath, forming free metal ions again in the alkaline solution.

[0012] To address at least one of the aforementioned technical problems, this application proposes an electrolysis apparatus. Utility Model Content

[0013] The purpose of this invention is to provide an electrolysis device that can effectively remove metal deposits caused by corrosion on the surface of the electrolysis device components, improve the efficiency and quality of pickling, and thus improve the overall hydrogen production performance.

[0014] The objective of this utility model is achieved through the following technical solution:

[0015] This utility model provides an electrolysis device, the electrolysis device comprising:

[0016] A reactor used for electrolyzing water to produce hydrogen and oxygen;

[0017] A hydrogen gas-liquid separator, wherein the first gas-liquid inlet of the hydrogen gas-liquid separator is connected to the first gas-liquid outlet of the reactor;

[0018] An oxygen gas-liquid separator, wherein the second gas-liquid inlet of the oxygen gas-liquid separator is connected to the second gas-liquid outlet of the reactor;

[0019] A cleaning assembly, connected to the reactor, the hydrogen gas-liquid separator, and / or the oxygen gas-liquid separator, is used to store the cleaning agent described above for acid washing and to supply the cleaning agent to the electrolysis unit during acid washing.

[0020] Furthermore, the cleaning component includes:

[0021] A first acid storage unit is used to store the cleaning agent.

[0022] A first acid injection valve, the first end of which is connected to the first acid 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;

[0023] A first acid injection pump is disposed between the first acid injection valve and the first acid storage unit.

[0024] Furthermore, the first acid injection valve is located between the alkaline inlet of the reactor and the second drain outlet of the hydrogen gas-liquid separator, and the first acid injection valve is located between the alkaline inlet of the reactor and the first drain outlet of the oxygen gas-liquid separator.

[0025] Furthermore, the electrolysis apparatus further includes: a backup component, the backup component comprising:

[0026] The second acid storage unit is used to store the cleaning agent;

[0027] The second acid injection valve has a first end connected to the second acid storage unit and a second end connected to the reactor, the hydrogen gas-liquid separator and / or the oxygen gas-liquid separator.

[0028] The second acid injection pump is disposed between the second acid injection valve and the second acid storage unit.

[0029] Furthermore, the first acid injection valve is located between the first gas-liquid outlet of the reactor and the first gas-liquid inlet of the hydrogen gas-liquid separator;

[0030] The second acid injection valve is located between the second gas-liquid outlet of the reactor and the second gas-liquid inlet of the oxygen gas-liquid separator.

[0031] Furthermore, the electrolysis apparatus further includes: an alkali solution pumping assembly, the alkali solution pumping assembly comprising:

[0032] An alkali storage unit, wherein the alkali storage unit is used to store the alkali solution;

[0033] 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;

[0034] An alkali injection pump is disposed between the alkali injection valve and the alkali storage unit.

[0035] Furthermore, the electrolysis device also includes: a three-way valve, the first end of which is connected to the first acid storage unit, the second end of which is connected to the alkali storage unit, and the third end of which is connected to the first acid injection pump;

[0036] The first acid injection valve is reused as the alkali injection valve, and the first acid injection pump is reused as the alkali injection pump.

[0037] Furthermore, the alkali pumping component is reused as an alkali pumping component to recover the alkali;

[0038] The cleaning component is reused as a first acid removal component to recover the cleaning agent.

[0039] Furthermore, the electrolysis apparatus also includes:

[0040] Piping assembly connecting the reactor, the hydrogen gas-liquid separator, the oxygen gas-liquid separator, and the cleaning assembly;

[0041] A circulation pump is mounted on the piping assembly.

[0042] Furthermore, the piping assembly includes:

[0043] 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;

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

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

[0050] The electrolysis device of this invention integrates a reactor, a hydrogen gas-liquid separator, an oxygen gas-liquid separator, and a cleaning component, enabling efficient acid washing operations and improving production efficiency. Attached Figure Description

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

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

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

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

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

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

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

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

[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 occurring in the metal structure of the electrolysis device according to an embodiment of this utility model.

[0061] In the diagram: 1. Reactor; 100. Membrane; 101. Electrode; 102. Separator; 103. Bipolar plate; 104. Switchboard; 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. 51. Alkali injection valve; 51. Cleaning assembly; 511. First acid storage unit; 512. First acid injection pump; 513. First acid injection valve; 52. Backup assembly; 521. Second acid storage unit; 522. Second acid injection pump; 523. Second acid injection 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; 8. Three-way valve; 91. Oxygen storage unit; 92. Hydrogen storage unit; M is metal. Detailed Implementation

[0062] 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.

[0063] 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.

[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] The electrolysis device of this invention includes: a reactor 1, a hydrogen gas-liquid separator 2, an oxygen gas-liquid separator 3, and a cleaning component 51. Further, the electrolysis device of this invention may also include: a backup component 52. Further, the electrolysis device of this invention may also include: a pipeline assembly 6 and a circulating pump 7. Further, the electrolysis device also includes: an alkali solution pumping assembly 4. The electrolysis device also includes: a three-way valve 8. Further, the electrolysis device of this invention may also include: a hydrogen storage unit 92 and an oxygen storage unit 91. Further, the electrolysis device of this invention may also include: an alkali solution pumping assembly (not shown), a first acid removal assembly (not shown), and a second acid removal assembly (not shown).

[0066] In some preferred embodiments, the electrolysis device of this invention is an electrolytic cell.

[0067] The alkali pumping assembly 4 of this invention is connected to the alkali inlet of reactor 1. In application, the alkali pumping assembly 4 is used to store alkali to supply alkali to reactor 1. In practical applications, reactor 1 consists of multiple reaction pools. (Reference) Figures 1-8 The reactor 1 of this invention is used 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 the 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 the 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, and this first mixture 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, and this second mixture will be separated into alkaline solution and oxygen inside the oxygen gas-liquid separator 3.

[0068] In this invention, the second exhaust port 24 of the hydrogen gas-liquid separator 2 is connected to the hydrogen storage unit 92, the first exhaust port 34 of the oxygen gas-liquid separator 3 is connected to the oxygen storage unit 91, and 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 alkali 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. In practical applications, the alkali pumping assembly 4 is reused as an alkali pumping assembly to recover alkali. Furthermore, the piping assembly 6 connects the reactor 1, the hydrogen gas-liquid separator 2, the oxygen gas-liquid separator 3, and the cleaning assembly 51, and a circulation pump 7 is installed on the piping assembly 6 to achieve liquid circulation within the piping assembly 6.

[0069] refer to Figures 1-8 The spare component 52 and the cleaning component 51 of this invention are connected to the reactor 1, the hydrogen gas-liquid separator 2, and / or the oxygen gas-liquid separator 3. In application, both the spare component 52 and the cleaning component 51 are used to store cleaning agents for acid washing and to provide cleaning agents to the electrolysis unit during acid washing. In practical applications, the cleaning component 51 is reused as a first acid removal component, and the spare component 52 is reused as a second acid removal component to recover the cleaning agent.

[0070] refer to Figures 1-8 The cleaning assembly 51 of this invention includes: a first acid storage unit 511, a first acid injection pump 512, and a first acid injection valve 513 connected in sequence. Specifically, the first acid storage unit 511 is used to store cleaning agent, and the second end of the first acid injection valve 513 is connected to the reactor 1, the hydrogen gas-liquid separator 2, and / or the oxygen gas-liquid separator 3. In application, the first acid injection valve 513 is opened, and the first acid injection pump 512 is started to pump the cleaning agent in the first acid storage unit 511 into the pipeline assembly 6 to participate in the acid washing cycle.

[0071] refer to Figure 6 The spare component 52 of this invention includes: a second acid storage unit 521, a second acid injection pump 522, and a second acid injection valve 523 connected in sequence. Specifically, the second acid storage unit 521 is used to store cleaning agent, and the second end of the second acid injection valve 523 is connected to the reactor 1, the hydrogen gas-liquid separator 2, and / or the oxygen gas-liquid separator 3. In application, the second acid injection valve 523 is opened, and the second acid injection pump 522 is started to pump the acid from the second acid storage unit 521 into the pipeline assembly 6 to participate in the acid washing cycle.

[0072] In some preferred embodiments, the first acid injection valve 513 is located between the alkali inlet of reactor 1 and the second drain outlet 22 of hydrogen gas-liquid separator 2, and also between the alkali inlet of reactor 1 and the first drain outlet 32 ​​of oxygen gas-liquid separator 3. In other preferred embodiments, the first acid injection valve 513 is located between the first gas-liquid outlet of reactor 1 and the first gas-liquid inlet 21 of hydrogen gas-liquid separator 2; and the second acid injection valve 523 is located between the second gas-liquid outlet of reactor 1 and the second gas-liquid inlet 31 of oxygen gas-liquid separator 3.

[0073] refer to Figures 1-8 The alkali solution pumping assembly 4 of this invention includes: an alkali storage unit 41, an alkali injection valve 43, and an alkali injection pump 42 connected in sequence. Specifically, the alkali storage unit 41 is used to store alkali solution, and 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. In application, the alkali injection valve 43 is opened, and the alkali injection pump 42 is started to pump the alkali solution in the alkali storage unit 41 into the pipeline assembly 6 to participate in the electrolysis reaction.

[0074] In some preferred embodiments, the electrolysis apparatus may further include a three-way valve 8. Specifically, refer to... Figure 2 The first end of the three-way valve 8 is connected to the first acid storage unit 511, the second end of the three-way valve 8 is connected to the alkali storage unit 41, and the third end of the three-way valve 8 is connected to the first acid injection pump 512. In application, the first acid injection valve 513 is reused as the alkali injection valve 43, and the first acid injection pump 512 is reused as the alkali injection pump 42, which can reduce the number of components used.

[0075] refer to Figures 1-8The pipeline assembly 6 of this utility model includes: a first pipeline 61, a second pipeline 62, a third pipeline 63, a fourth pipeline 64, a fifth pipeline 65, and a sixth pipeline 66. Specifically, the first end of the first pipeline 61 is connected to the second gas-liquid outlet of the reactor 1, and the second end of the first pipeline 61 is connected to the second gas-liquid inlet 31 of the oxygen gas-liquid separator 3; the first end of the second pipeline 62 is connected to the first gas-liquid outlet of the reactor 1, and the second end of the second pipeline 62 is connected to the first gas-liquid inlet 21 of the hydrogen gas-liquid separator 2; the first end of the third pipeline 63 is connected to the second drain port 22 of the hydrogen gas-liquid separator 2, and the second end of the third pipeline 63 is connected to the alkaline inlet of the reactor 1; the first end of the fourth pipeline 64 is connected to the first drain port 32 of the oxygen gas-liquid separator 3, and the second end of the fourth pipeline 65 is connected to the second gas-liquid inlet 36 of the reactor 1. The second end is connected to the alkaline inlet of reactor 1; the first end of the sixth pipe 66 is connected to the alkaline inlet of reactor 1, the second end of the sixth pipe 66 is connected to the second end of the third pipe 63 and the second end of the fourth pipe 64; the first end of the fifth pipe 65 is connected to the second cylinder (not shown) of the liquid phase of hydrogen gas-liquid separator 2, and the second end of the fifth pipe 65 is connected to the first cylinder (not shown) of the liquid phase of oxygen gas-liquid separator 3; preferably, the first end of the fifth pipe 65 is connected to the second liquid phase 23 of the second cylinder of the liquid phase, and the second end of the fifth pipe 65 is connected to the first liquid phase 33 of the first cylinder of the liquid phase.

[0076] In some embodiments, reference Figure 1 The cleaning component 51 is installed on the sixth pipeline 66. During application, the first acid injection valve 513 is opened and the first acid injection pump 512 is started to pump the cleaning agent in the first acid storage unit 511 into the sixth pipeline 66, and then into the pipeline component 6 to participate in the acid washing cycle.

[0077] In other embodiments, reference is made to... Figure 2 The cleaning component 51 is installed on the third pipeline 63. During application, the first acid injection valve 513 is opened and the first acid injection pump 512 is started to pump the cleaning agent in the first acid storage unit 511 into the third pipeline 63, and then into the pipeline component 6 to participate in the acid washing cycle.

[0078] In other embodiments, reference is made to... Figure 3 The cleaning component 51 is installed on the fourth pipeline 64. During application, the first acid injection valve 513 is opened and the first acid injection pump 512 is started to pump the cleaning agent in the first acid storage unit 511 into the fourth pipeline 64, and then into the pipeline assembly 6 to participate in the acid washing cycle.

[0079] In other embodiments, reference is made to... Figure 5The cleaning component 51 is installed on the pipeline where the third pipeline 63 and the fourth pipeline 64 converge. In application, the first acid injection valve 513 is opened and the first acid injection pump 512 is started to pump the cleaning agent in the first acid storage unit 511 into the pipeline where the third pipeline 63 and the fourth pipeline 64 converge, and then into the pipeline component 6 to participate in the acid washing cycle.

[0080] In other embodiments, reference is made to... Figure 4 The system includes two sets of cleaning components 51, one set installed on the third pipeline 63 and the other set installed on the fourth pipeline 64. In application, the first acid injection valve 513 of both sets of cleaning components 51 is opened, and the first acid injection pump 512 of both sets of cleaning components 51 is started. The cleaning agent in the first acid storage unit 511 of both sets of cleaning components 51 is pumped into the third pipeline 63 and the fourth pipeline 64 respectively, and then into the pipeline assembly 6 to participate in the acid washing cycle. In application, one set of cleaning components 51 can be replaced by a spare component 52. The spare component 52 can be installed on either the third pipeline 63 or the fourth pipeline 64.

[0081] In other embodiments, reference is made to... Figure 7 The cleaning component 51 is installed on the second pipeline 62. During application, the first acid injection valve 513 is opened and the first acid injection pump 512 is started to pump the cleaning agent in the first acid storage unit 511 into the second pipeline 62, and then into the pipeline assembly 6 to participate in the acid washing cycle.

[0082] In other embodiments, reference is made to... Figure 8 The cleaning component 51 is installed on the first pipeline 61. During application, the first acid injection valve 513 is opened and the first acid injection pump 512 is started to pump the cleaning agent in the first acid storage unit 511 into the first pipeline 61, and then into the pipeline component 6 to participate in the acid washing cycle.

[0083] In other embodiments, two sets of cleaning components 51 are included, one set disposed on a first pipeline 61 and the other set disposed on a second pipeline 62. In application, the first acid injection valve 513 of both sets of cleaning components 51 is opened, and the first acid injection pump 512 of both sets of cleaning components 51 is started, pumping the cleaning agent from the first acid storage unit 511 of both sets of cleaning components 51 into the first pipeline 61 and the second pipeline 62 respectively, and then into the pipeline assembly 6 to participate in the acid washing cycle. For application, refer to... Figure 6 One of the cleaning components 51 can be replaced by a spare component 52. The spare component 52 can be installed on the first pipe 61 or on the second pipe 62.

[0084] Furthermore, the pickling method of this utility model includes steps SS1-SS4:

[0085] Step SS1: Add the cleaning agent for pickling to the cleaning component 51 of the electrolysis unit.

[0086] Before adding cleaning agent, the alkali solution in the electrolysis unit needs to be pumped out. To simplify the unit structure, reduce production costs, and improve equipment utilization, the alkali inlet component 4 is reused as an alkali outlet component. In this case, the alkali injection pump 42 is a bidirectional pump. In application, bidirectional liquid transport can be achieved by changing the rotation direction of the centrifugal pump impeller.

[0087] Specifically, open the alkali injection valve 43 and start the alkali injection pump 42 to pump the alkali solution separated by the hydrogen gas-liquid separator 2 and the oxygen gas-liquid separator 3 into the alkali storage unit 41 to recover the alkali solution, reduce environmental pollution and production costs, and then close the alkali injection valve 43 and the alkali injection pump 42. Next, open the first acid injection valve 513 and start the first acid injection pump 512 to pump the cleaning agent in the first acid storage unit 511 into the pipeline assembly 6. If a backup assembly 52 is provided, the second acid injection valve 523 can also be opened and the second acid injection pump 522 can be started to pump the cleaning agent in the second acid storage unit 521 into the pipeline assembly 6. After the cleaning agent addition step is completed, close the first acid injection valve 513, the first acid injection pump 512, the second acid injection valve 523, and the second acid injection pump 522. Then, start the circulation pump 7 to circulate the cleaning agent in the electrolysis unit and ensure that the cleaning agent is evenly distributed in the electrolysis unit to improve the pickling effect. In application, a heat exchanger can also be set up to regulate the temperature of the cleaning agent. In practical applications, the temperature of the cleaning agent can be adjusted between 10 and 60°C using a heat exchanger.

[0088] Step SS2: Detect the metal ion concentration of the cleaning agent in the electrolysis device.

[0089] When applying cleaning agents, methods for determining the content of dissolved metal ions include, but are not limited to, ultraviolet-visible spectroscopy, atomic absorption spectrometry (AAS), inductively coupled plasma mass spectrometry (ICP), and liquid chromatography.

[0090] This invention allows for better control of pickling time and process by continuously monitoring the metal ion concentration of the cleaning agent in the electrolysis device. In practical applications, a monitoring system connected to an application programming interface (API) can be set up to achieve automatic addition of cleaning agent.

[0091] Step SS3: When the metal ion concentration is greater than or equal to the preset concentration, replace the cleaning agent.

[0092] During the pickling process, the cleaning agent gradually dissolves the metal electrodeposited on the electrode surface, or dissolves the metal or metal oxides deposited on any pipes or components (electrodes, gas-liquid separators, etc.). When the metal ion concentration is greater than or equal to the preset concentration, the electrolytic cell is considered not clean, and the acid solution needs to be replaced, and another cleaning cycle begins.

[0093] Specifically, the cleaning component 51 is reused as the first acid drainage component, and the spare component 52 is reused as the second acid drainage component. At this time, both the first acid injection pump 512 and the second acid injection pump 522 are bidirectional pumps. First, the first acid injection valve 513 and the second acid injection valve 523 are opened, and the first acid injection pump 512 and the second acid injection pump 522 are started, pumping the cleaning agent containing dissolved metal ions from the pipeline assembly 6 into the first acid storage unit 511 and the second acid storage unit 521. Next, the circulation pump 7, the first acid injection valve 513, the first acid injection pump 512, the second acid injection valve 523, and the second acid injection pump 522 are shut off, and the cleaning agent in the first acid storage unit 511 and the second acid storage unit 521 is replaced with new cleaning agent. Then, the first acid injection valve 513 and the second acid injection valve 523 are opened, and the first acid injection pump 512 and the second acid injection pump 522 are started, pumping the new cleaning agent from the first acid storage unit 511 and the second acid storage unit 521 into the pipeline assembly 6. Finally, close the first acid injection valve 513, the first acid injection pump 512, the second acid injection valve 523, and the second acid injection pump 522, and start the circulation pump 7 to allow new cleaning agent to enter the acid washing cycle.

[0094] Step SS4: When the metal ion concentration is less than the preset concentration and remains unchanged for a preset time, the pickling ends.

[0095] When the metal ion concentration is less than a preset concentration and remains constant within a preset time, the electrolysis device is considered clean and can be reused for hydrogen production. To ensure stable performance of the cleaning agent during acid pickling and improve the pickling effect, the preset concentration of this invention is less than or equal to the saturated solubility of the metal ions in the cleaning agent. Preferably, the preset concentration is less than or equal to the difference between the saturated solubility of the metal ions in the cleaning agent and a preset threshold.

[0096] After pickling, the cleaning agent in the electrolysis unit needs to be pumped out, and new alkali solution needs to be pumped into the electrolysis unit. Specifically, the first acid injection valve 513 and the second acid injection valve 523 are opened, and the first acid injection pump 512 and the second acid injection pump 522 are started to pump the cleaning agent containing dissolved metal ions in the pipeline assembly 6 into the first acid storage unit 511 and the second acid storage unit 521. Next, the circulation pump 7, the first acid injection valve 513, the first acid injection pump 512, the second acid injection valve 523, and the second acid injection pump 522 are closed, and the alkali injection valve 43 is opened, and the alkali injection pump 42 is started to pump the alkali solution in the alkali storage unit 41 into the pipeline assembly 6. Then, the circulation pump 7 is started to allow the alkali solution to enter the reactor 1 to participate in the electrolysis reaction.

[0097] On the other hand, the cleaning agents used for pickling mentioned above include chelating agents. Furthermore, the cleaning agents may also include pH buffers and / or corrosion inhibitors.

[0098] The chelating agent of this invention can remove metal deposits caused by corrosion. Specifically, the chelating agent of this invention can reduce iron ions, reduce nickel ions, and form a nickel passivation layer with nickel oxide, which helps prevent metal corrosion and improves the durability of the cleaned metal. In application, to increase the dissolution kinetics of metal ions and dissolve more metal ions, the chelating agent of this invention is one or more combinations of etidronic acid, oxalic acid, citric acid, or phosphoric acid. For example: the chelating agent is etidronic acid; the chelating agent is oxalic acid; the chelating agent is etidronic acid and oxalic acid; the chelating agent is etidronic acid and citric acid; the chelating agent is etidronic acid and phosphoric acid; the chelating agent is oxalic acid and citric acid; the chelating agent is oxalic acid and phosphoric acid; the chelating agent is etidronic acid, oxalic acid, and citric acid; the chelating agent is etidronic acid, oxalic acid, and phosphoric acid.

[0099] Etidromic acid, also known as 1-hydroxyethane, 1,1-dimethylbisphosphonic acid, or HEDPA, belongs to the bisphosphonic acid family. Its pKa1 = 1.56 and pKa2 = 2.20. HEDPA is an iron and iron oxide chelating agent (β-phosphate chelator). Fe 3+ =16.2,β Fe 2+ =3.0), which can increase the overall solubility of dissolved iron in the mixture, accelerate the dissolution process of mixed valence iron oxide in water, and has corrosion protection properties. It can continue to dissolve iron even if the pH of the cleaning solution rises.

[0100] Oxalic acid is both a chelating agent and a reducing agent, with pKa1 = 1.2 and pKa2 = 4.3. It can reduce poorly soluble iron oxide particles, such as Fe2O3. Like etidronic acid, oxalic acid accelerates the dissolution of mixed-valence iron oxides in water and possesses corrosion-protective properties.

[0101] Furthermore, it is important to emphasize that oxalic acid, as a reducing agent, can also protect nickel (from nickel-based electrodes) and the nickel passivation layer, which serves as a protective layer. Specifically, oxalic acid reacts with oxides on the surface of nickel materials to form a relatively stable nickel oxalate film (i.e., the nickel oxalate passivation layer). This film passivates the surface of the nickel material, preventing further oxidation. The nickel oxalate film is dense and not easily damaged, thus effectively protecting the nickel material from corrosion and oxidation. The oxalic acid-passivated nickel material exhibits good corrosion resistance and oxidation resistance, and the passivation layer has good thermal stability, maintaining its passivation effect at high temperatures.

[0102]

[0103] During electrolysis, metal ions are reduced to metallic components (M) on the cathode side. This process can lead to the formation of metal deposits in various parts of the electrolytic cell. These deposits not only occupy the active surfaces of the electrodes, reducing electrolysis efficiency, but may also threaten the structural integrity of the electrolytic cell. By removing these metal deposits or metal contamination, the active surfaces of the electrodes can be restored, enabling them to participate more effectively in the water dissociation reaction. Acid washing, as an effective cleaning method, can significantly improve the overall performance of the electrolytic cell and extend its service life.

[0104] When selecting a cleaning agent, the strength of the acid is a key factor. While citric acid has some cleaning ability, its effectiveness may be limited for certain hard-to-dissolve metal deposits. In contrast, etidronic acid and oxalic acid, being stronger acids than citric acid, can dissolve metal impurities deposited in the electrolytic cell more quickly, improving the dissolution reaction kinetics. This means that, within the same cleaning time, using etidronic acid and / or oxalic acid can achieve higher cleaning efficiency, thus more effectively removing metal deposits and restoring the performance of the electrolytic cell.

[0105] Although etidronic acid and oxalic acid are stronger acids, their use in electrolytic cells and hydrogen environments remains safe. They are harmless to operators and do not pose an explosion risk or other hazard. Furthermore, etidronic acid and oxalic acid do not corrode nickel materials or degrade the integrity of the electrolytic cell (especially the electrodes or diaphragm). Therefore, using etidronic acid and oxalic acid to clean electrolytic cells ensures both effective cleaning and operational safety.

[0106] When etidronic acid and / or oxalic acid are used as cleaning agents, they can dissolve metal ion deposits, such as ferric ion deposits. These ferric deposits can not only hinder the normal operation of electrodes but also clog the diaphragm, without interfering with the smooth circulation of liquids and gases within the system. Cleaning agents containing etidronic acid or oxalic acid have excellent cleaning effects, removing as many metal ion deposits as possible without damaging any nickel-based components or nickel-based coatings in the electrolytic cell. When stainless steel equipment is cleaned with cleaning agents, its unique chemical composition—a metal-based alloy containing precious metals such as nickel and chromium—makes the reaction more complex. The cleaning agent first dissolves free metal ions, such as ferric ions, on the stainless steel surface, while the precious metal components are retained.

[0107] It is important to emphasize that after pickling, when the stainless steel surface comes into contact with oxygen in the air, oxalic acid acts as an excellent initiator for the nickel-phosphonic acid mixed passivation layer. This lowers the activation energy of the nickel-phosphonic acid reaction, allowing the formation of a nickel-phosphonic acid mixed passivation layer composed of nickel oxalate, phosphate, and hydroxide at relatively low temperatures and concentrations. Due to the synergistic effect of oxalic acid and phosphonic acid, the resulting nickel-phosphonic acid mixed passivation layer exhibits stronger corrosion resistance than nickel oxalate films, resisting the erosion of various corrosive media and thus extending the service life of nickel materials. Furthermore, compared to nickel oxalate films, the nickel-phosphonic acid mixed passivation layer adheres more tightly to the surface of the nickel material, preventing corrosive media from penetrating into the material's interior. Moreover, the nickel-phosphonic acid mixed passivation layer possesses excellent thermal stability, maintaining its passivation effect at high temperatures. Therefore, even in harsh working environments, the passivation layer can continuously provide protection.

[0108] To ensure that the cleaning agent effectively removes contaminants without causing excessive corrosion to the metal, the oxalic acid concentration in this invention is 0.1wt% to 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%; the etidronic acid concentration is 1wt% to 5wt%, for example... The concentrations of the following components are specified: 1.0 wt%, 2.0 wt%, 3.0 wt%, 4.0 wt%, or 5.0 wt%; the concentration of citric acid is 1 wt% to 5 wt%, for example: 1.0 wt%, 2.0 wt%, 3.0 wt%, 4.0 wt%, or 5.0 wt%; the concentration of phosphoric acid is 1 wt% to 5 wt%, for example: 1.0 wt%, 2.0 wt%, 3.0 wt%, 4.0 wt%, or 5.0 wt%; in some preferred embodiments, the chelating agent of this invention includes etidronic acid and oxalic acid. The etidronic acid concentration is 3 wt%, and the oxalic acid concentration is 1 wt%. The synergistic effect of etidronic acid and oxalic acid enables more efficient removal of deposits on metal surfaces.

[0109] To make the objectives, technical solutions, and advantages of this utility model clearer, embodiments 1-5 are provided for further detailed explanation. Specifically, the parameters of the cleaning agents and their cleaning effects in embodiments 1-5 are detailed in Tables 1 and 2. It should be understood that the specific embodiments described herein are merely illustrative of this utility model and are not intended to limit its scope.

[0110] Table 1: Cleaning Agent Parameters

[0111] oxalic acid EDTA-1,000 Citric acid Phosphoric acid Example 1 4wt% - - - Example 2 - 4wt% - - Example 3 - - 10wt% 2wt% Example 4 1wt% 3wt% - - Example 5 - - 4wt% -

[0112] Table 2: Acid pickling effect of cleaning agents

[0113]

[0114]

[0115] In addition, the addition of pH buffers and corrosion inhibitors helps stabilize the pH value of the cleaning agent, reducing corrosion to the metal and improving the cleaning effect. The corrosion inhibitor of this invention has a mass concentration of 1wt% to 5wt%, for example: 1.0wt%, 2.0wt%, 3.0wt%, 4.0wt%, or 5.0wt%. When applied, the corrosion inhibitor includes a quaternary ammonium compound. The cleaning agent of this invention has a pH value of 1-5, for example: 1, 2, 3, 4, or 5. When applied, the pH buffer includes boric acid.

[0116] 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.

[0117] 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. An electrolysis apparatus, characterized in that, The electrolysis apparatus includes: Reactor (1), said reactor (1) is used for electrolyzing water to generate hydrogen and oxygen; Hydrogen gas-liquid separator (2), wherein the first gas-liquid inlet (21) of the hydrogen gas-liquid separator (2) is connected to the first gas-liquid outlet of the reactor (1); An oxygen gas-liquid separator (3) is provided, wherein the second gas-liquid inlet (31) of the oxygen gas-liquid separator (3) is connected to the second gas-liquid outlet of the reactor (1); A cleaning assembly (51), connected to the reactor (1), the hydrogen gas-liquid separator (2) and / or the oxygen gas-liquid separator (3), is used to store cleaning agent for acid washing and to supply the cleaning agent to the electrolysis unit during acid washing.

2. The electrolysis apparatus according to claim 1, characterized in that, The cleaning component (51) includes: A first acid storage unit (511) is used to store the cleaning agent; The first acid injection valve has a first end connected to the first acid storage unit (511) and a second end connected to the reactor (1), the hydrogen gas-liquid separator (2) and / or the oxygen gas-liquid separator (3). A first acid injection pump (512) is disposed between the first acid injection valve and the first acid storage unit (511).

3. The electrolysis apparatus according to claim 2, characterized in that, The first acid injection valve is located between the alkaline inlet of the reactor (1) and the second drain port (22) of the hydrogen gas-liquid separator (2), and the first acid injection valve is located between the alkaline inlet of the reactor (1) and the first drain port (32) of the oxygen gas-liquid separator (3).

4. The electrolysis apparatus according to claim 2, characterized in that, The electrolysis apparatus further includes: a backup component (52), the backup component (52) comprising: The second acid storage unit (521) is used to store the cleaning agent; The second acid injection valve (523) has its first end connected to the second acid storage unit (521) and its second end connected to the reactor (1), the hydrogen gas-liquid separator (2) and / or the oxygen gas-liquid separator (3). A second acid injection pump (522) is disposed between the second acid injection valve (523) and the second acid storage unit (521).

5. The electrolysis apparatus according to claim 4, characterized in that, The first acid injection valve is located between the first gas-liquid outlet of the reactor (1) and the first gas-liquid inlet (21) of the hydrogen gas-liquid separator (2); The second acid injection valve (523) is located between the second gas-liquid outlet of the reactor (1) and the second gas-liquid inlet (31) of the oxygen gas-liquid separator (3).

6. The electrolysis apparatus according to claim 2, characterized in that, The electrolysis device further includes: an alkali solution pumping assembly (4), the alkali solution pumping assembly (4) comprising: 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).

7. The electrolysis apparatus according to claim 6, characterized in that, The electrolysis device further includes: a three-way valve (8), the first end of which is connected to the first acid storage unit (511), the second end of which is connected to the alkali storage unit (41), and the third end of which is connected to the first acid injection pump (512). The first acid injection valve is reused as the alkali injection valve (43), and the first acid injection pump (512) is reused as the alkali injection pump (42).

8. The electrolysis apparatus according to claim 6, characterized in that, The alkali pumping component (4) is reused as an alkali pumping component to recover the alkali; The cleaning component (51) is reused as a first acid removal component to recover the cleaning agent.

9. The electrolysis apparatus according to claim 1, characterized in that, The electrolysis apparatus further includes: Piping assembly (6) connecting the reactor (1), the hydrogen gas-liquid separator (2), the oxygen gas-liquid separator (3) and the cleaning assembly (51); A circulation pump (7) is mounted on the pipeline assembly (6).

10. The electrolysis apparatus according to claim 9, 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 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. 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).

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