Electrolytic bath and sodium hypochlorite generator

Abstract

The invention provides an electrolytic bath and a sodium hypochlorite generator, the electrolytic bath comprises a reaction unit, the reaction unit comprises an air cathode and an anode which are in a sheet shape and are arranged at an interval, the air cathode and the anode are sealed through a sealing spacer and form a liquid chamber, an air chamber is formed on one side, far away from the anode, of the air cathode, and the air chamber is communicated with the liquid chamber. The air cathode is used for reducing oxygen into hydroxyl ions; and the sealing spacers are arranged in the electrolytic bath in a criss-cross manner, so that a liquid chamber and a gas chamber which are isolated from each other are formed. The oxygen reduction reaction is adopted to replace the traditional cathode hydrogen evolution reaction, the structure is simple, the sealing spacers in the device are arranged in a criss-cross mode, it is guaranteed that oxygen makes full contact with an air cathode catalyst layer, and the problems of electrolyte disturbance, reaction efficiency reduction and the like caused by mixing of air and saline water are solved.

Description

An electrolytic cell and a sodium hypochlorite generator Technical Field

[0001] This invention relates to the field of sodium hypochlorite preparation, and more specifically, to an electrolytic cell and a sodium hypochlorite generator. Background Technology

[0002] Sodium hypochlorite, as a highly efficient, broad-spectrum, and environmentally friendly chlorine-based disinfectant, is widely used in various fields such as municipal wastewater disinfection, hospital wastewater treatment, aquaculture, drinking water purification, and organic matter bleaching. The safety, energy efficiency, and stability of its preparation technology have always been core research directions in the industry. Currently, sodium hypochlorite is mainly prepared in two ways: by purchasing commercial solution and by on-site electrolytic preparation. Purchasing has drawbacks such as easy degradation of available chlorine, high transportation and storage costs, and significant corrosive safety risks. Therefore, on-site electrolytic preparation has become the mainstream technical approach.

[0003] Patent application number 202310868737.4 discloses a bipolar membrane electrolysis device and method for preparing sodium hypochlorite by electrolyzing sodium chloride. The cathode undergoes a hydrogen evolution reaction, and the electrolysis cell is strictly divided into a cathode chamber and an anode chamber by a bipolar membrane. The anode and cathode reactions are completed in independent chambers. The water dissociation characteristics of the bipolar membrane are used to achieve directional ion migration, reducing side reactions at the source. However, hydrogen is flammable and explosive, and as a cathode product, it still poses a significant safety hazard. Furthermore, the device is complex and costly. Patent application number 201910530903.3 discloses a miniature air cathode sodium hypochlorite generator, including an electrolyte tank, a DSA anode, an air cathode, and an inlet. This generator uses an air cathode and can produce sodium hypochlorite disinfectant by electrolyzing brine at a low voltage of 2V. However, this device is a miniature single electrolysis cell, belonging to a simple laboratory / small-scale civilian-grade device, and has not been designed for industrialization.

[0004] Therefore, there is an urgent need for an air cathode electrolyzer and sodium hypochlorite generator that are free from safety hazards, suitable for large-scale industrial design, simple in structure, and low in cost. Summary of the Invention

[0005] In view of this, the present invention aims to provide an electrolytic cell and a sodium hypochlorite generator to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0007] The present invention provides an electrolytic cell including a reaction unit, the reaction unit including an air cathode and an anode arranged in a sheet shape and spaced apart, the air cathode and the anode being sealed together by a sealing spacer to form a liquid chamber, and a gas chamber being formed on the side of the air cathode away from the anode, the air cathode being used to reduce oxygen to hydroxide ions.

[0008] This invention completely eliminates hydrogen generation by replacing the traditional cathode hydrogen evolution reaction with the oxygen reduction reaction of the air cathode, combined with the isolated structure design of the liquid and gas chambers, thus eliminating the risk of flammability and explosion at the source.

[0009] Furthermore, the reaction unit includes an anode and two air cathodes, which are spaced apart on both sides of the anode.

[0010] Furthermore, at least one of the reaction units is provided in the electrolytic cell; when two or more reaction units are provided, a sealing spacer is provided between adjacent reaction units.

[0011] In this invention, the reaction units are reconfigurable and can be flexibly stacked according to production capacity requirements, which improves the structural adaptability and production capacity adjustment flexibility of the electrolyzer, laying a structural foundation for the efficient and stable operation of the overall device.

[0012] Furthermore, the sealing spacer has a hollow area in the center of its plate, and the hollow area extends outward along the horizontal or vertical edge to form a medium passage; the sealing spacer is arranged in a crisscross pattern in the electrolytic cell, thereby forming liquid chambers and gas chambers that are isolated from each other.

[0013] It should be noted that, in this invention, the sealing spacer in which the hollowed-out area extends outward along its longitudinal edge to form a medium through hole is defined as longitudinally arranged, and the sealing spacer in which the hollowed-out area extends outward along its transverse edge to form a medium through hole is defined as transversely arranged.

[0014] In a preferred embodiment of the present invention, the sealing spacer is also provided with medium through holes on both sides of the plate that do not extend outward.

[0015] Furthermore, the sealing spacer is longitudinally arranged between the air cathode and the anode to form a liquid chamber for containing the liquid medium; the sealing spacer is transversely arranged between adjacent air cathodes to form an air chamber for containing air.

[0016] Furthermore, the electrolytic cell also includes end plates disposed at both ends of the reaction unit, and a transverse sealing spacer is provided between the outermost air cathode and the end plate to form a gas chamber for containing air.

[0017] This invention arranges the sealing spacers in a crisscross pattern within the electrolytic cell, forming liquid and gas chambers that are isolated from each other by the air cathode, anode, and end plate. This structurally achieves non-mixing flow of liquid and gas media, ensuring that the electrolytic chlorine reaction and the cathode oxygen reduction reaction proceed in an orderly manner within independent spaces.

[0018] Furthermore, the air cathode includes a conductive substrate, a cathode catalyst layer, and a hydrophobic layer; the conductive substrate includes a nickel plate with a centrally hollowed-out area and nickel foam, the nickel foam being welded and fixed within the hollowed-out area of ​​the nickel plate; the cathode catalyst layer and the hydrophobic layer are sequentially disposed on the side of the nickel foam closest to the liquid chamber; the anode is a metal oxide anode plate, and anode catalysts are disposed on both sides of the metal oxide anode plate.

[0019] This invention provides sufficient gas contact area for the oxygen reduction reaction by welding nickel foam to the hollow area of ​​the nickel plate, while also enhancing the strength of the cathode plate. The cathode catalyst layer and hydrophobic layer are layered on the side of the nickel foam near the liquid chamber, so that the electrolyte forms a stable liquid film on the surface of the catalyst layer, constructing a highly efficient gas-liquid-solid three-phase reaction interface, which greatly improves the catalytic efficiency of the oxygen reduction reaction and reduces the reaction energy consumption. At the same time, the hydrophobic layer can effectively prevent the electrolyte from seeping into the gas side, ensuring the smooth flow of gas and avoiding damage to the cathode reaction efficiency.

[0020] Furthermore, the sealing spacer, air cathode, and anode are provided with mounting holes, and fasteners are inserted into the mounting holes for overall clamping and stress buffering.

[0021] Furthermore, the sealing spacer, air cathode, and anode are provided with mounting and positioning holes at their four corners to assist in assembly and positioning.

[0022] In a preferred embodiment of the present invention, the end plate is also provided with mounting holes and mounting positioning holes, which correspond to the positions of the mounting holes and mounting positioning holes on the sealing spacer, the air cathode and the anode.

[0023] In a preferred embodiment of the present invention, a PLC programmable controller and a sensor are also included. The signal output terminal of the sensor is communicatively connected to the signal input terminal of the PLC programmable controller, and is used to automatically adjust the brine flow rate, electrolysis current and air supply.

[0024] This invention utilizes a PLC programmable controller in conjunction with various sensors to achieve automated regulation of brine flow, electrolysis current, and air supply. It can dynamically adjust parameters in real time according to the actual reaction conditions of the electrolyzer, ensuring that reaction conditions are always maintained within the optimal range. This stabilizes the effective chlorine concentration of the sodium hypochlorite solution, improving the accuracy and consistency of product concentration. Simultaneously, automated control replaces manual adjustment, reducing human error, enhancing the intelligence level of the electrolyzer's operation, lowering manual operating costs, ensuring continuous and stable operation of the equipment, and adapting to the needs of industrial mass production.

[0025] The present invention also provides a sodium hypochlorite generator, comprising the electrolytic cell described in the above technical solution; the sodium hypochlorite generator further comprises a brine preparation unit, a sodium hypochlorite storage tank and a blower, wherein the blower supplies air to the electrolytic cell; one end of the electrolytic cell is connected to the brine preparation unit and the other end is connected to the sodium hypochlorite storage tank.

[0026] This invention, through the coordinated setup of a brine preparation unit, a sodium hypochlorite storage tank, a blower, and an electrolytic cell, forms an integrated continuous operation process flow encompassing brine supply, electrolytic reaction, product storage, and oxygen supply. This enables continuous on-site preparation and storage of sodium hypochlorite, avoiding problems such as effective chlorine degradation and high transportation and storage costs associated with purchasing sodium hypochlorite. The blower continuously supplies air to the electrolytic cell, providing sufficient oxygen reactants for the cathode oxygen reduction reaction, ensuring its efficient execution and further improving sodium hypochlorite generation efficiency. The integrated system design makes the generator compact, facilitating on-site installation and use, and enhancing the equipment's practical application adaptability and industrialization potential.

[0027] Compared with existing technologies, the electrolytic cell and sodium hypochlorite generator described in this invention have the following advantages:

[0028] This invention replaces the traditional cathode hydrogen evolution reaction with an oxygen reduction reaction at an air cathode. Combined with directionally arranged sealed spacers to form isolated liquid and gas chambers, it completely eliminates hydrogen generation, eradicating flammable and explosive safety hazards at the source. It eliminates the need for complex explosion-proof and hydrogen handling systems, significantly reducing site safety requirements and achieving inherent device safety. Furthermore, the use of crisscrossing sealed spacers and optimized electrode and flow path design improves reaction efficiency, reduces energy consumption, and adapts to various sodium hypochlorite preparation needs. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0030] Figure 1 is a top view of the electrolytic cell of the present invention;

[0031] Figure 2 is a schematic diagram of the longitudinal arrangement of the sealing spacer according to the present invention;

[0032] Figure 3 is a schematic diagram of the lateral arrangement of the sealing spacer according to the present invention;

[0033] Figure 4 is an exploded view of the electrolytic cell consisting of one anode and two cathodes according to the present invention;

[0034] Figure 5 is a schematic diagram of the cathode described in this invention;

[0035] Figure 6 is a side cross-sectional view of the cathode described in this invention;

[0036] Figure 7 is a schematic diagram of the anode described in this invention;

[0037] Figure 8 is a schematic diagram of the inlet end plate and the outlet end plate of the present invention;

[0038] Figure 9 is a schematic diagram of the structure and flow of the sodium hypochlorite generator described in this invention.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1. End plate; 1-1. Inlet end plate; 1-2. Outlet end plate; 2. Sealing spacer; 3. Air cathode; 3-1. Cathode connection hole; 3-2. Nickel plate; 3-3. Nickel foam; 3-4. Cathode catalyst layer; 3-5. Hydrophobic layer; 4. Anode; 4-1. Anode connection hole; 5. Fasteners; 5-1. Fastening bolts; 5-2. Insulating sleeve; 6. Mounting and fixing holes; 7. Mounting and positioning holes; 8. Reaction unit; 9. Gas chamber; 9-1. Gas medium inlet; 9-2. Gas medium outlet; 10. Liquid chamber; 10-1. Liquid medium inlet; 10-2. Liquid medium outlet. Detailed Implementation

[0041] The present invention will be further described below with reference to specific embodiments. First, it should be noted that the data in the following experimental examples were obtained by the inventors through numerous experiments. Due to space limitations, only a portion of these data is shown in the specification, and those skilled in the art can understand and implement the present invention based on this data. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the contents of this invention, those skilled in the art can make various modifications or alterations to the invention, and these modifications or alterations also fall within the scope of protection of this application.

[0042] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0043] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0044] In traditional electrolysis, the cathode undergoes the hydrogen evolution reaction, where water molecules gain electrons and are reduced to hydrogen gas and hydroxide ions. During this process, hydrogen gas, a flammable and explosive gas, is continuously produced. In contrast, the cathode in air cathode electrolysis undergoes the oxygen reduction reaction. It utilizes a catalyst to directly introduce oxygen from the air as a reactant. The oxygen gains electrons and is reduced to hydroxide ions, a process that produces no hydrogen gas whatsoever.

[0045] It should be noted that the reaction principle of the air cathode electrolysis method is existing technology, and will not be described in detail here.

[0046] As shown in Figure 1, this embodiment provides an electrolytic cell including a reaction unit 8. The reaction unit 8 includes an air cathode 3 and an anode 4 that are plate-shaped and spaced apart. The air cathode 3 and the anode 4 are sealed together by a sealing spacer 2 to form a liquid chamber 10. The side of the air cathode 3 away from the anode 4 forms a gas chamber 9. The air cathode 3 is used to reduce oxygen to hydroxide ions.

[0047] In this embodiment, the reaction unit 8 includes an anode 4 and two air cathodes 3, which are spaced apart on both sides of the anode 4.

[0048] In this embodiment, at least one reaction unit 8 is provided in the electrolytic cell; when two or more reaction units 8 are provided, a sealing spacer 2 is provided between adjacent reaction units 8.

[0049] In this embodiment, the sealing spacer 2, the air cathode 3, and the anode 4 are all provided with medium through holes for medium flow, forming liquid flow paths and gas flow paths.

[0050] In this invention, it should be explained that in a reaction unit 8, the air cathode 3 and the sealing spacer 2 are each in pairs and symmetrically attached to both sides of the anode 4; the sealing spacer 2, the air cathode 3, and the anode 4 are all provided with medium through holes, which are divided into medium inlets and medium outlets, wherein the medium inlets include gas medium inlets 9-1 and liquid medium inlets 10-1, and the medium outlets include gas medium outlets 9-2 and liquid medium outlets 10-2; the gas medium inlets 9-1, liquid medium inlets 10-1, gas medium outlets 9-2, and liquid medium outlets 10-2 on each component are aligned and corresponding, so that after the components are stacked and attached, the medium through holes at the corresponding positions are connected in sequence, forming independent liquid flow paths and air flow paths respectively.

[0051] As shown in Figures 2-3, in this embodiment, the sealing spacer 2 has a hollow area in the center of its plate, and the hollow area extends outward along the horizontal or vertical edge to form a medium passage hole; the sealing spacer 2 is arranged in a crisscross pattern in the electrolytic cell, thereby forming a liquid chamber 10 and a gas chamber 9 that are isolated from each other.

[0052] It should be explained here that the setting direction of the sealing spacer 2 is adapted to the direction of the medium through hole formed by the extension of its hollow area: when the hollow area extends outward along the horizontal edge to form the medium through hole, the sealing spacer 2 is set horizontally; when the hollow area extends outward along the vertical edge to form the medium through hole, the sealing spacer 2 is set vertically, and the sealing spacer 2 is also provided with medium through holes on the two side plates that do not extend outward. The medium through holes on the non-extended side are only used for auxiliary flow guidance and will not damage the overall seal of the liquid chamber / gas chamber.

[0053] In this embodiment, the sealing spacer 2 is arranged longitudinally between the air cathode 3 and the anode 4 to form a liquid chamber 10 for containing liquid medium; the sealing spacer 2 is arranged laterally between adjacent air cathodes 3 to form an air chamber 9 for containing air.

[0054] In this embodiment, the electrolytic cell further includes end plates 1 disposed at both ends of the reaction unit 8, and a transverse sealing spacer 2 is provided between the outermost air cathode 3 and the end plate 1 to form a gas chamber 9 for containing air.

[0055] The present invention arranges the sealing spacers in a crisscross pattern within the electrolytic cell to form independent and isolated liquid and gas chambers, which are respectively connected to the liquid medium through hole and the gas medium through hole, ensuring that the liquid medium and the gas medium do not mix within the electrolytic cell.

[0056] It should be explained that the sealing spacer 2 is arranged longitudinally between the air cathode 3 and the anode 4 to form a liquid chamber 10 for containing liquid medium; the sealing spacer 2 is arranged laterally between adjacent air cathodes 3 or between the air cathode 3 and the end plate 1 to form an air chamber 9 for containing air.

[0057] Figure 4 is a schematic diagram of an electrolytic cell consisting of one anode and two cathodes according to the present invention, wherein the sealing spacers are arranged in a crisscross pattern inside the electrolytic cell.

[0058] It needs to be explained that the liquid chamber is the liquid phase space in the electrolytic cell where the brine undergoes an electrolytic reaction. The anode and air cathode are respectively attached to both sides of a single liquid chamber, and the chamber is surrounded and sealed by a solid plate of a sealing spacer. The hollow area in the center of the sealing spacer provides the main space for the liquid medium to be contained and reacted. During operation, the anode and cathode and the liquid medium inlet in the sealing spacer are connected. The sealing spacer is arranged longitudinally, and the hollow area in the center extends outward along the longitudinal edge to form the liquid medium inlet and / or outlet, so that the dilute brine can smoothly enter the chamber and make full contact with the electrodes, and the liquid medium after the reaction can also be smoothly discharged through the channel.

[0059] The gas chamber is the gas phase space for the oxygen reduction reaction within the electrolytic cell. Each gas chamber has two air cathodes attached to each side, or one side with an air cathode and the other with an end plate. It is surrounded and sealed by a solid plate of a sealing spacer. A hollow area in the center of the sealing spacer provides the main space for air medium to be contained and transferred. During operation, the gas chamber and the gas medium inlet of the sealing spacer are connected. The sealing spacer is horizontally positioned, and the hollow area in the center extends outwards along its horizontal edge to form a gas medium inlet and / or outlet, allowing air to smoothly enter the chamber and fully contact the conductive substrate of the air cathode. The exhaust gas after the oxygen reduction reaction can also be smoothly discharged through the channels, forming a closed and independent gas phase mass transfer chamber. The gas flow path in the end plate is connected to the medium channel of the sealing spacer, allowing air to continuously enter the chamber and provide sufficient reactants for the oxygen reduction reaction. The exhaust gas after the reaction can also be smoothly discharged through the channels.

[0060] In a preferred embodiment, the sealing spacer 2 is made of an elastic material, preferably fluororubber or EPDM rubber, which provides good sealing performance.

[0061] As shown in Figures 5-6, in this embodiment, the air cathode 3 includes a conductive substrate, a cathode catalyst layer 3-4, and a hydrophobic layer 3-5; the conductive substrate includes a nickel plate 3-2 with a centrally hollowed-out area and nickel foam 3-3, the nickel foam 3-3 being welded and fixed within the hollowed-out area of ​​the nickel plate 3-2; the cathode catalyst layer 3-4 and the hydrophobic layer 3-5 are sequentially disposed on the side of the nickel foam 3-3 near the liquid chamber 10.

[0062] Figure 6 is a side view of the cathode of the present invention, wherein the left side of the cathode is a gas chamber and the right side is a liquid chamber.

[0063] It should be noted that the cathode catalyst layer of the present invention is sandwiched between nickel foam and a hydrophobic layer. The hydrophobic layer enables the electrolyte (liquid medium) to form a liquid film on the surface of the catalyst layer. At the same time, the nickel foam has a porous structure and strong gas conductivity, thus constructing a stable gas-liquid-solid three-phase reaction interface on the surface of the catalyst layer, providing reaction conditions for the oxygen reduction reaction.

[0064] In a preferred embodiment, the cathode catalyst layer 3-4 is a coating loaded with catalysts such as platinum and carbon, and the hydrophobic layer 3-5 is a porous polytetrafluoroethylene membrane; the air cathode 3 is provided with a cathode connection hole 3-1 for connecting to an external power supply line to realize the conduction of electrolysis current.

[0065] As shown in Figure 7, in this embodiment, the anode 4 is a metal oxide anode plate, and an anode catalyst is disposed on both sides of the metal oxide anode plate.

[0066] In a preferred embodiment, the metal oxide anode plate is a titanium-based anode plate, and the anode catalyst is a precious metal oxide catalyst such as ruthenium or iridium; the anode 4 is provided with an anode connection hole 4-1 for connecting to an external power supply line to realize the conduction of electrolytic current.

[0067] As shown in Figure 8, in a preferred embodiment of this invention, the end plate 1 includes an inlet end plate 1-1 and an outlet end plate 1-2. The inlet end plate 1-1 has a liquid medium inlet 10-1 at its lower part and a gas medium inlet 9-1 on its right side, which are respectively connected to the gas flow path and liquid flow path inside the electrolytic cell. The outlet end plate 1-2 has a liquid medium outlet 10-2 at its upper part and a gas medium outlet 9-2 on its left side, which are respectively connected to the gas flow path and liquid flow path inside the electrolytic cell, thereby realizing the directional flow of air and brine and the export of the reaction medium.

[0068] As shown in Figures 1-8, in this embodiment, the end plate 1, the sealing spacer 2, the air cathode 3 and the anode 4 are provided with mounting holes 6, and fasteners 5 are inserted into the mounting holes 6 for overall clamping and stress buffering.

[0069] As shown in Figure 4, in a preferred embodiment, the fastener 5 includes a fastening bolt 5-1 and an insulating sleeve 5-2. The insulating sleeve 5-2 is sleeved on the outside of the bolt of the fastening bolt 5-1 and embedded in the mounting hole 6. After the fastening bolt 5-1 passes through the mounting holes 6 of the end plate 1, the sealing spacer 2, the air cathode 3, and the anode 4 in sequence, it is locked by a nut to achieve a tight fit between the components of the electrolytic cell and ensure sealing performance. The insulating sleeve 5-2 effectively isolates the fastening bolt 5-1 from each electrode component to prevent electrolytic current leakage and avoid short circuit faults. At the same time, it plays a role in buffering stress during the locking process to prevent deformation of each component due to excessive clamping force.

[0070] In a preferred embodiment, the diameter of the mounting holes 6 on the air cathode 3 and anode 4 is larger than the diameter of the mounting holes 6 on the end plate 1 and the sealing spacer 2, which can prevent short circuits between electrodes.

[0071] As shown in Figures 1-8, in this embodiment, the end plate 1, the sealing spacer 2, the air cathode 3 and the anode 4 are provided with mounting positioning holes 7 at their four corners for auxiliary installation.

[0072] It should be noted that the mounting positioning hole 7 and the mounting fixing hole 6 are coaxially corresponding on each component. During installation, a positioning pin can be inserted to achieve rapid coaxial positioning of the end plate 1, sealing spacer 2, air cathode 3 and anode 4.

[0073] In one embodiment of the present invention, the outer contour dimensions of the sealing spacer 2, the air cathode 3 and the anode 4 are equal and smaller than the outer contour dimensions of the end plate 1. The assembled electrolytic cell is placed on a plane, with only the end plate 1 in contact with the plane, thus avoiding contact between the charged electrode plates and the outside world and eliminating the possibility of forming an external short circuit between the anode and cathode.

[0074] In this embodiment, a PLC programmable controller and a sensor are also included. The signal output terminal of the sensor is communicatively connected to the signal input terminal of the PLC programmable controller, and is used to automatically adjust the brine flow rate, electrolysis current and air supply.

[0075] It should be noted that the configuration of the PLC programmable controller and the sensor is existing technology, and will not be described in detail here.

[0076] In this embodiment, the following reactions occur at the cathode and anode in the electrolytic cell:

[0077]

[0078] This embodiment also provides a sodium hypochlorite generator, including the electrolytic cell described in the above technical solution.

[0079] In this embodiment, the sodium hypochlorite generator further includes a brine preparation unit, a sodium hypochlorite storage tank, and a blower, wherein the blower supplies air to the electrolytic cell; one end of the electrolytic cell is connected to the brine preparation unit, and the other end is connected to the sodium hypochlorite storage tank.

[0080] In this embodiment, the brine preparation unit provides the electrolyzer with dilute brine that meets the reaction concentration requirements. Its output end is connected to the liquid medium inlet 10-1 of the electrolyzer through a pipeline. The input end of the sodium hypochlorite storage tank is connected to the liquid medium outlet 10-2 of the electrolyzer through a pipeline, and is used to store the sodium hypochlorite solution generated by the electrolytic reaction, so as to realize the continuous preparation and storage of sodium hypochlorite solution. The output end of the blower is connected to the gas medium inlet 9-1 of the electrolyzer through a pipeline, and continuously supplies air to the gas chamber 9, so as to provide sufficient oxygen reactants for the oxygen reduction reaction.

[0081] In a preferred embodiment, the brine preparation unit includes a water softener, a salt dissolving tank, a concentrated brine tank, a filter, a mixer, and a dilute brine tank connected in sequence. The dilute brine tank is connected to the electrolytic cell via a pipeline. A heat exchanger is also provided between the blower and the electrolytic cell to adjust the temperature of the air delivered by the blower to a suitable temperature.

[0082] The water softener removes calcium and magnesium ions from the raw water to prevent scale buildup and blockage of the flow path in the electrolytic cell; the salt dissolving tank dissolves industrial salt into saturated concentrated brine, and the concentrated brine tank stores and stably supplies the brine; the filter removes suspended impurities from the concentrated brine to prevent them from entering the electrolytic cell and affecting electrode performance; the mixer mixes the filtered concentrated brine with softened water in a specific ratio to dilute it to 3%~5% brine, and the dilute brine tank stores and stably supplies the brine to the electrolytic cell; the heat exchanger is a temperature-controlled heat exchange device that automatically adjusts the heat exchange power based on temperature sensor signals received by the PLC programmable controller, adjusting the air temperature delivered by the fan to the high-efficiency range of the electrochemical reaction to ensure the efficiency of the oxygen reduction reaction and chlorine evolution reaction; each pipeline of the sodium hypochlorite generator is equipped with valves, joints, and other fittings to achieve pipeline on / off control and connection sealing.

[0083] In this invention, a rectifier power supply applies a DC current density of 2000 A / m² to the electrolytic cell. The chlorine gas generated at the anode dissolves into the electrolyte and mixes thoroughly with the hydroxide ions generated at the cathode, rapidly reacting to generate sodium hypochlorite. The resulting sodium hypochlorite solution overflows into a sodium hypochlorite storage tank for later use.

[0084] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. An electrolytic cell, comprising a reaction unit (8), characterized in that, The reaction unit (8) includes an air cathode (3) and an anode (4) arranged in sheet form and spaced apart. The air cathode (3) and the anode (4) are sealed together by a sealing spacer (2) to form a liquid chamber (10). A gas chamber (9) is formed on the side of the air cathode (3) away from the anode (4). The air cathode (3) is used to reduce oxygen to hydroxide ions.

2. The electrolytic cell according to claim 1, characterized in that, The reaction unit (8) includes an anode (4) and two air cathodes (3), which are spaced apart on both sides of the anode (4).

3. The electrolytic cell according to claim 2, characterized in that, At least one reaction unit (8) is provided in the electrolytic cell; when two or more reaction units (8) are provided, a sealing spacer (2) is provided between adjacent reaction units (8).

4. The electrolytic cell according to claim 1, characterized in that, The sealing spacer (2) has a hollow area in the center of the plate, and the hollow area extends outward along the horizontal or vertical edge to form a medium passage hole; the sealing spacer (2) is arranged in a crisscross pattern in the electrolytic cell to form a liquid chamber (10) and a gas chamber (9) that are isolated from each other.

5. The electrolytic cell according to claim 4, characterized in that, The sealing spacer (2) is arranged longitudinally between the air cathode (3) and the anode (4) to form a liquid chamber (10) for containing liquid medium; the sealing spacer (2) is arranged laterally between adjacent air cathodes (3) to form an air chamber (9) for containing air.

6. The electrolytic cell according to claim 4, characterized in that, The electrolytic cell also includes end plates (1) disposed at both ends of the reaction unit (8), and a transverse sealing spacer (2) is provided between the outermost air cathode (3) and the end plate (1) to form a gas chamber (9) for containing air.

7. The electrolytic cell according to claim 1, characterized in that, The air cathode (3) includes a conductive substrate, a cathode catalyst layer (3-4), and a hydrophobic layer (3-5); the conductive substrate includes a nickel plate (3-2) with a central hollow area and nickel foam (3-3), the nickel foam (3-3) being welded and fixed in the hollow area of ​​the nickel plate (3-2); the nickel foam (3-3) is provided with a cathode catalyst layer (3-4) and a hydrophobic layer (3-5) on the side of the liquid chamber (10) in sequence; the anode (4) is a metal oxide anode plate, and the metal oxide anode plate is provided with an anode catalyst on both sides.

8. The electrolytic cell according to claim 1, characterized in that, The sealing spacer (2), air cathode (3) and anode (4) are provided with mounting holes (6), and fasteners (5) are inserted into the mounting holes (6) for overall compression and stress buffering.

9. The electrolytic cell according to claim 1, characterized in that, The sealing spacer (2), air cathode (3) and anode (4) are provided with mounting positioning holes (7) at their four corners for auxiliary assembly positioning.

10. A sodium hypochlorite generator, characterized in that, The electrolytic cell includes any one of claims 1 to 9; the sodium hypochlorite generator further includes a brine preparation unit, a sodium hypochlorite storage tank, and a blower, wherein the blower supplies air to the electrolytic cell; one end of the electrolytic cell is connected to the brine preparation unit, and the other end is connected to the sodium hypochlorite storage tank.

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