A device and system for producing sodium hypochlorite by electrolysis of seawater with power saving

Abstract

This invention discloses an energy-saving device and system for preparing sodium hypochlorite by electrolyzing seawater. The device includes a main electrolytic cell and two or more sub-electrolytic cells. A diversion control module, based on the detection results of the seawater parameter detection module, pumps seawater from the main electrolytic cell to the sub-electrolytic cell with the optimal electrolysis parameters for continued electrolysis, while simultaneously replenishing the main electrolytic cell with fresh seawater, dynamically maintaining the composition and concentration of the seawater within the main electrolytic cell within a preset range. This technical solution achieves dual optimization of energy consumption and side reactions through multi-stage electrolytic cells, dynamic parameter control, and customized catalysts. Setting optimal electrolysis parameters in different cells according to seawater composition differences reduces overall energy consumption; by suppressing magnesium hydroxide precipitation, oxygen evolution reaction, and bromide interference, the incidence of side reactions is reduced, while electrode life is extended, increasing sodium hypochlorite yield and significantly improving electrolysis efficiency and economic benefits.

Description

Technical Field

[0001] This application relates to the field of seawater electrolysis, specifically to an apparatus and system for energy-saving electrolysis of seawater to produce sodium hypochlorite. Background Technology

[0002] Sodium hypochlorite has a wide range of applications in the industrial field, becoming an indispensable chemical due to its strong oxidizing properties. In the water treatment industry, it serves as a highly efficient bactericide and disinfectant, rapidly inactivating bacteria and viruses and removing algae and odors from water. In textile printing and dyeing, it is used for bleaching cotton and linen fabrics, improving whiteness and dyeing effects. In the paper industry, it can oxidize lignin to achieve pulp bleaching. In addition, it is often used in industrial wastewater treatment to degrade toxic pollutants such as phenols and cyanides, and as a bactericide for oilfield reinjection water to prevent microbial corrosion of pipelines.

[0003] Sodium hypochlorite can be prepared mainly through electrolysis, chemical methods, and metathesis methods. Electrolysis is the mainstream industrial method, producing sodium chlorate by electrolyzing sodium chloride solution. It boasts advantages such as high yield, high purity (≥98%), and mature technology, making it suitable for large-scale production. However, it suffers from drawbacks including high energy consumption, large equipment investment, and the risk of hydrogen explosion. Chemical methods utilize the alkaline disproportionation of sodium chlorate or the high-temperature reaction of chlorine with sodium hydroxide. These methods are simple, use readily available raw materials, and are suitable for small-scale or laboratory settings. However, the product purity is low, and there are numerous side reactions. Metathesis methods produce sodium chlorate by reacting sodium perchlorate with potassium chloride. Due to high raw material costs and separation difficulties, its industrial application is extremely limited. Currently, electrolysis accounts for over 90% of industrial production capacity due to its efficiency and purity advantages, while reducing energy consumption and equipment costs is its main optimization direction.

[0004] The core of preparing sodium hypochlorite by electrolysis of seawater is to convert NaCl in seawater into chlorine and NaOH through an electrolytic reaction, which then react to form NaClO. The key challenges lie in the pretreatment of seawater impurities and the control of electrolysis conditions. Specifically, the salinity, pH value, and electrolysis temperature all affect electrolysis efficiency. Low salinity (such as in nearshore seawater) reduces chloride ion concentration, leading to decreased electrolysis efficiency; excessively high salinity increases energy consumption. Chlorine readily volatilizes under acidic conditions, while alkaline conditions promote hypochlorite formation; however, hypochlorite readily decomposes at pH > 10. Increasing the electrolysis temperature promotes the reaction between chlorine and hydroxide ions, but temperatures exceeding 40°C accelerate hypochlorite decomposition.

[0005] Furthermore, seawater contains magnesium ions, calcium ions, sulfate ions, and other ions, all of which can trigger side reactions. Specifically, magnesium ions react with hydroxide ions to form magnesium hydroxide precipitate, which may clog the electrodes or affect electrolysis efficiency; bromide ions may be oxidized, affecting the purity of NaClO, requiring pretreatment control. Therefore, how to efficiently prepare sodium hypochlorite via electrolysis is a pressing technical problem that needs to be solved in this field. Summary of the Invention

[0006] In view of the above problems, this application provides an energy-saving device for preparing sodium hypochlorite by electrolyzing seawater, which solves the technical problems of high energy consumption and easy occurrence of side reactions in the electrolytic preparation of sodium hypochlorite.

[0007] To achieve the above objectives, this application provides an energy-saving device for preparing sodium hypochlorite by electrolyzing seawater, comprising: a main electrolytic cell and two or more sub-electrolytic cells; each of the main electrolytic cell and each sub-electrolytic cell is provided with a positive electrode and a negative electrode, and the electrolysis voltage and current parameters of the main electrolytic cell and each of the sub-electrolytic cells can be dynamically adjusted independently, and the main electrolytic cell is connected to each of the sub-electrolytic cells through different pumping pipes;

[0008] The device for preparing sodium hypochlorite by electrolyzing seawater in an energy-saving manner also includes a seawater parameter detection module, a diversion control module, and a parameter fine-tuning module;

[0009] The seawater parameter detection module is used to detect the composition and concentration of seawater in the main electrolytic cell and each of the sub-electrolytic cells in real time;

[0010] The diversion control module is used to pump the seawater in the main electrolysis cell to the sub-electrolysis cell with the optimal electrolysis parameters according to the detection results of the seawater parameter detection module, so as to continue electrolysis, and at the same time replenish the main electrolysis cell with new seawater, so that the composition and concentration of the seawater in the main electrolysis cell are dynamically maintained within a preset range.

[0011] The parameter fine-tuning module fine-tunes the electrolysis voltage and current parameters in the main electrolytic cell and each of the sub-electrolytic cells based on the detection results of the seawater parameters in the seawater parameter detection module, so as to adapt to the seawater parameters in each cell and achieve the best electrolysis efficiency.

[0012] Furthermore, the diversion control module controls the diversion of seawater between the main electrolyzer and the sub-electrolyzer according to a preset seawater composition-electrolyzer matching rule.

[0013] Furthermore, the diversion control module controls the diversion of seawater between the main electrolyzer and the sub-electrolyzer according to a preset seawater composition-electrolyzer matching rule, including:

[0014] Based on the degree of influence of various parameters in seawater on electrolysis efficiency, the basic weighting coefficients of each parameter are preset;

[0015] A parameter-electrolysis efficiency sensitivity matrix is ​​constructed using historical electrolysis data. The weight coefficients of each parameter are dynamically adjusted based on the real-time fluctuation range of seawater parameters. When the fluctuation range of a certain parameter exceeds the preset fluctuation threshold, the weight coefficient of that parameter is increased by 20%-50%, while the weight coefficients of other parameters are decreased proportionally.

[0016] The detected parameters are weighted according to the aforementioned basic weighting coefficients;

[0017] Based on the weighted comprehensive score, the seawater in the main electrolyzer is diverted to the sub-electrolyzer with the highest comprehensive score. Each sub-electrolyzer has a comprehensive score-optimal electrolysis parameter comparison table established in advance based on historical data, which is used to determine the electrolysis voltage, current, temperature and pH value of the corresponding sub-electrolyzer.

[0018] Furthermore, the diversion control module controls the diversion of seawater between the main electrolyzer and the sub-electrolyzer according to a preset seawater composition-electrolyzer matching rule, and also includes:

[0019] Calculate the actual electrolysis efficiency of each of the sub-electrolytes;

[0020] The actual electrolysis efficiency of each sub-electrolytic cell is compared with the preset electrolysis efficiency. Based on the comparison results, the weight coefficients in the weight calculation unit and the fluctuation thresholds in the weight dynamic adjustment unit are corrected in reverse to form a closed-loop optimization system.

[0021] Furthermore, the seawater parameters include, but are not limited to, sodium chloride concentration, pH value, magnesium ion concentration, and calcium ion concentration.

[0022] Furthermore, the parameter fine-tuning module dynamically adjusts the electrolysis parameters of each electrolyzer through the established mathematical model of electrolysis parameters and seawater parameters.

[0023] Furthermore, the electrode surfaces of the main electrolyzer and each of the sub-electrolyzers are loaded with catalyst coatings of different compositions to adapt to different seawater compositions and electrolysis parameters;

[0024] The electrode catalyst of the main electrolyzer adopts a ruthenium-iridium-titanium ternary coating, wherein the molar ratio of ruthenium:iridium:titanium is 5:3:2;

[0025] The electrode catalyst of the first sub-electrolyte uses a ruthenium-iridium-tin coating, wherein the molar ratio of ruthenium:iridium:tin is 4:4:2;

[0026] The electrode catalyst of the second sub-electrolyte uses a platinum-iridium coating, wherein the molar ratio of platinum to iridium is 7:3.

[0027] Furthermore, each of the sub-electrolytes is equipped with an independent modulation cell, the modulation cell comprising:

[0028] pH detection unit: Real-time detection of the pH value of seawater pumped into the main electrolyzer;

[0029] Acid-base addition unit: pH value is adjusted by adding hydrochloric acid or sodium hydroxide solution according to the preset ideal pH range of the sub-electrolyte;

[0030] Intelligent control unit: When the detected pH value differs from the ideal pH value of the sub-electrolyzer by more than ±0.5, the modulation process is triggered; if the difference is ≤ ±0.5, the modulation tank is skipped and the seawater is directly transported to the sub-electrolyzer.

[0031] To address the aforementioned technical problems, this application also provides another technical solution:

[0032] A system for producing sodium hypochlorite by electrolyzing seawater in an energy-saving manner, comprising:

[0033] An electrolysis apparatus includes: a main electrolytic cell and two or more sub-electrolytic cells; each of the main electrolytic cell and each sub-electrolytic cell is provided with a positive electrode and a negative electrode, and the electrolysis voltage and current parameters of the main electrolytic cell and each of the sub-electrolytic cells can be dynamically adjusted independently, and the main electrolytic cell is connected to each of the sub-electrolytic cells through different pumping pipes;

[0034] The monitoring device includes a seawater parameter detection module, a diversion control module, and a parameter fine-tuning module;

[0035] The seawater parameter detection module is used to detect the composition and concentration of seawater in the main electrolytic cell and each of the sub-electrolytic cells in real time;

[0036] The diversion control module is used to pump the seawater in the main electrolysis cell to the sub-electrolysis cell with the optimal electrolysis parameters according to the detection results of the seawater parameter detection module, so as to continue electrolysis, and at the same time replenish the main electrolysis cell with new seawater, so that the composition and concentration of the seawater in the main electrolysis cell are dynamically maintained within a preset range.

[0037] The parameter fine-tuning module fine-tunes the electrolysis voltage and current parameters in the main electrolytic cell and each of the sub-electrolytic cells based on the detection results of the seawater parameters in the seawater parameter detection module, so as to adapt to the seawater parameters in each cell and achieve the best electrolysis efficiency.

[0038] Furthermore, the diversion control module controls the diversion of seawater between the main electrolyzer and the sub-electrolyzer according to a preset seawater composition-electrolyzer matching rule.

[0039] Unlike existing technologies, the above-mentioned energy-saving electrolysis of seawater to prepare sodium hypochlorite apparatus and system includes a main electrolytic cell and two or more sub-electrolytic cells. A diversion control module, based on the detection results of the seawater parameter detection module, pumps seawater from the main electrolytic cell to the sub-electrolytic cell with the optimal electrolysis parameters for continued electrolysis, while simultaneously replenishing the main electrolytic cell with fresh seawater, dynamically maintaining the composition and concentration of the seawater within the main electrolytic cell within a preset range. This technical solution achieves dual optimization of energy consumption and side reactions through multi-stage electrolytic cells, dynamic parameter control, and customized catalysts. Setting optimal electrolysis parameters in different cells according to seawater composition differences reduces overall energy consumption; by suppressing magnesium hydroxide precipitation, oxygen evolution reaction, and bromide interference, the incidence of side reactions is reduced, while electrode life is extended, increasing sodium hypochlorite yield and significantly improving electrolysis efficiency and economic benefits.

[0040] The above description of the invention is merely an overview of the technical solution of this application. In order to enable those skilled in the art to better understand the technical solution of this application and to implement it based on the description and drawings, and to make the above-mentioned objectives and other objectives, features and advantages of this application easier to understand, the following description is provided in conjunction with the specific embodiments and drawings of this application. Attached Figure Description

[0041] The accompanying drawings are only used to illustrate the principles, implementation methods, applications, features, and effects of specific embodiments of the present invention and other related contents, and should not be considered as limitations on this application.

[0042] In the accompanying drawings of the instruction manual:

[0043] Figure 1 This is a block diagram of the device for preparing sodium hypochlorite by energy-saving electrolysis of seawater according to a specific embodiment;

[0044] Figure 2 This is a schematic diagram showing the connection between the main electrolytic cell and the sub-electrolytic cell in a specific embodiment.

[0045] Figure 3 A data comparison table of the apparatus for preparing sodium hypochlorite described in the specific embodiments and conventional equipment;

[0046] Figure 4 The scoring table for the sub-electrolyte cell described in the specific implementation method;

[0047] Figure 5 This is a block diagram of the system for preparing sodium hypochlorite by energy-saving electrolysis of seawater according to a specific embodiment;

[0048] The reference numerals used in the above figures are explained as follows:

[0049] 100. Apparatus for preparing sodium hypochlorite by energy-saving electrolysis of seawater; 1. Main electrolyzer; 11. Electrode assembly; 2. Sub-electrolyzer; 22. Modulation cell; 3. Seawater parameter detection module; 4. Diversion control module; 5. Parameter fine-tuning module;

[0050] 200. A system for producing sodium hypochlorite by electrolyzing seawater in an energy-saving manner; 201. An electrolysis device; 202. A monitoring device; Detailed Implementation

[0051] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description, in conjunction with the listed specific embodiments and accompanying drawings, provides a detailed explanation. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended to limit the scope of protection of this application.

[0052] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0053] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0054] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0055] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.

[0056] Without further limitations, the use of terms such as “comprising,” “including,” “having,” or other similar open-ended expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0057] As understood in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0058] In the description of the embodiments of this application, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or drawings. They are only for the purpose of describing the specific embodiments of this application or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0059] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this application, should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. For those skilled in the art to which this application pertains, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0060] Please see Figure 1This embodiment provides an energy-saving device 100 for preparing sodium hypochlorite by electrolyzing seawater. The device 100 prepares sodium hypochlorite by electrolyzing seawater. The device 100 includes: a main electrolytic cell 1 and two or more sub-electrolytic cells 2, a seawater parameter detection module 3, a flow control module 4, and a parameter fine-tuning module 5.

[0061] like Figure 2 The diagram shown illustrates the connection between the main electrolytic cell and the sub-electrolytic cells in this embodiment. Each of the main electrolytic cell 1 and each sub-electrolytic cell 2 is equipped with an electrode assembly 11, which includes a positive electrode and a negative electrode arranged opposite each other. The electrolysis voltage and current parameters of the main electrolytic cell and each of the sub-electrolytic cells can be dynamically adjusted independently, and the main electrolytic cell is connected to each of the sub-electrolytic cells via different pumping pipes. In both the main electrolytic cell and each sub-electrolytic cell, an electrolysis reaction is used to convert NaCl in seawater into chlorine gas and sodium hydroxide, which then react to form sodium hypochlorite. The only difference is that the electrolysis parameters are set differently in each electrolytic cell, allowing the main electrolytic cell to operate within its optimal electrolysis efficiency range.

[0062] The seawater parameter detection module 3 is used to detect the composition and concentration of seawater in the main electrolytic cell and each of the sub-electrolytic cells in real time. The seawater parameters include, but are not limited to, sodium chloride concentration, pH value, magnesium ion concentration, and calcium ion concentration. The diversion control module 4 is used to, based on the detection results of the seawater parameter detection module, pump seawater from the main electrolytic cell to the sub-electrolytic cell with the optimal electrolysis parameters for continued electrolysis, while simultaneously replenishing the main electrolytic cell with new seawater, so that the composition and concentration of seawater in the main electrolytic cell are dynamically maintained within a preset range. The parameter fine-tuning module 5, based on the detection results of the seawater parameters in the main electrolytic cell and each of the sub-electrolytic cells by the seawater parameter detection module, fine-tunes the electrolysis voltage and current parameters in the main electrolytic cell and each of the sub-electrolytic cells to adapt to the seawater parameters in each cell and achieve optimal electrolysis efficiency.

[0063] In this embodiment, the main electrolytic cell 1 is the main equipment for seawater electrolysis, and its volume can be 8-15 m³. The volume of the sub-electrolytic cell 2 is smaller than that of the main electrolytic cell 1, and its volume can be 5-8 m³. In this embodiment, as... Figure 2 As shown, in this embodiment, three sub-electrolytes are set up, which are used to electrolyze seawater with different NaCl concentrations.

[0064] Indicatively, the first sub-electrolyte is used to electrolyze seawater with a NaCl concentration >30g / L (i.e., medium-to-high concentration seawater), the second sub-electrolyte is used to electrolyze seawater with a NaCl concentration of 15-30g / L (i.e., medium concentration seawater), and the third sub-electrolyte is used to electrolyze seawater with a NaCl concentration <15g / L (i.e., low concentration seawater).

[0065] To adapt to different seawater compositions and electrolysis parameters, the electrode surfaces of the main electrolytic cell and each of the sub-electrolytic cells are loaded with catalyst coatings of different compositions.

[0066] The electrode catalyst of the main electrolytic cell adopts a ruthenium-iridium-titanium ternary coating, that is, the positive electrode surface is coated with a ruthenium-iridium-titanium ternary coating (thickness 4μm), wherein the molar ratio of ruthenium:iridium:titanium is 5:3:2; the negative electrode adopts a nickel-based electrode. The main electrolytic cell is designed with a current density of 3500A / m² and a temperature of 78℃. Furthermore, the main electrolytic cell is equipped with a multi-parameter online detector for real-time monitoring of sodium chloride concentration (accuracy ±0.5g / L), pH value (±0.02), magnesium ions (±2ppm), calcium ions (±1ppm), and bromide ions (±0.5ppm).

[0067] The electrode catalyst of the first sub-electrolyte uses a ruthenium-iridium-tin coating, that is, the positive electrode surface is coated with a ruthenium-iridium-tin coating, wherein the molar ratio of ruthenium:iridium:tin is 4:4:2; the preset current density of the first sub-electrolyte is 3000A / m², and the pH is 8.2.

[0068] The electrode catalyst of the second sub-electrolyte uses a platinum-iridium coating, that is, the positive electrode surface is coated with a platinum-iridium coating, wherein the molar ratio of platinum to iridium is 7:3. The preset current density of the second sub-electrolyte is 2200A / m², and the pH is 9.0.

[0069] The third sub-electrolyte uses manganese dioxide-modified titanium-based electrodes, with a current density of 1500 A / m² and a temperature of 45℃.

[0070] During the main electrolysis stage:

[0071] Seawater enters the main electrolysis cell at a preset flow rate, such as 15 m³ / h. The initial parameters of the seawater are: sodium chloride 32 g / L, pH 8.0, magnesium ions 55 ppm, and calcium ions 12 ppm.

[0072] After electrolysis in the main electrolytic cell at a set voltage (e.g., 3.4V) for a certain time (e.g., 25 minutes), the detector measures the real-time data of the seawater: NaCl = 24g / L, pH = 9.3, magnesium ions = 48ppm, and calcium ions = 10ppm. Then, according to the preset seawater composition-electrolytic cell matching rules, the seawater is controlled to enter the corresponding sub-electrolytic cell from the main electrolytic cell for continued electrolysis.

[0073] In this embodiment, the diversion control module controls the diversion of seawater between the main electrolyzer and the sub-electrolyzer according to a preset seawater composition-electrolyzer matching rule, and further includes:

[0074] Calculate the actual electrolysis efficiency of each of the sub-electrolytes;

[0075] The actual electrolysis efficiency of each sub-electrolytic cell is compared with the preset electrolysis efficiency. Based on the comparison results, the weight coefficients in the weight calculation unit and the fluctuation thresholds in the weight dynamic adjustment unit are corrected in reverse to form a closed-loop optimization system.

[0076] The parameter fine-tuning module dynamically adjusts the electrolysis parameters of each electrolyzer through an established mathematical model of electrolysis parameters and seawater parameters.

[0077] like Figure 2 As shown, in this embodiment, each of the sub-electrolytic cells 2 is equipped with an independent modulation cell 22. The modulation cell includes:

[0078] pH detection unit: Real-time detection of the pH value of seawater pumped into the main electrolyzer;

[0079] Acid-base addition unit: pH value is adjusted by adding hydrochloric acid or sodium hydroxide solution according to the preset ideal pH range of the sub-electrolyte;

[0080] Intelligent control unit: When the detected pH value differs from the ideal pH value of the sub-electrolyzer by more than ±0.5, the modulation process is triggered; if the difference is ≤ ±0.5, the modulation tank is skipped and the seawater is directly transported to the sub-electrolyzer.

[0081] In existing technologies, during seawater electrolysis, key components in the seawater (such as NaCl concentration, magnesium ion and calcium ion impurity content, and pH value) change significantly with the reaction progress. In the initial stage of electrolysis, the NaCl concentration in the seawater is high (approximately 3.5%), suitable for rapid chlorine production at high current densities. However, impurity ions (such as magnesium ions) easily precipitate under alkaline conditions, clogging the electrodes. In the later stages of electrolysis, the NaCl concentration decreases while the hydroxide ion concentration increases. Maintaining the original parameters would lead to increased cell voltage and a surge in energy consumption.

[0082] In this embodiment, a main electrolytic cell 1 and two or more sub-electrolytic cells 2 are provided. The diversion control module 4, based on the detection results of the seawater parameter detection module, pumps seawater from the main electrolytic cell 1 to the sub-electrolytic cell 2 with the optimal electrolysis parameters for continued electrolysis, while simultaneously replenishing the main electrolytic cell 1 with new seawater, dynamically maintaining the composition and concentration of the seawater in the main electrolytic cell within a preset range. In this embodiment, by dynamically adjusting parameters for each cell (e.g., using a high current density in the first sub-electrolytic cell for medium-to-high concentration seawater, and a low temperature + low voltage in the second sub-electrolytic cell for low concentration seawater), the overall electrolysis efficiency can be improved and the electrolysis energy consumption reduced. This technical solution achieves dual optimization of energy consumption and side reactions through multi-stage electrolytic cells, dynamic parameter control, and customized catalysts. Figure 3As shown, by setting the optimal electrolysis parameters for different tanks according to the differences in seawater composition, the overall energy consumption can be reduced; by suppressing magnesium hydroxide precipitation, oxygen evolution reaction and bromide interference, the incidence of side reactions can be reduced, the electrode life can be extended, the sodium hypochlorite yield can be increased, and the electrolysis efficiency and economic benefits can be significantly improved.

[0083] The diversion control module controls the diversion of seawater between the main electrolyzer and the sub-electrolyzer according to a preset seawater composition-electrolyzer matching rule. The diversion control module controls the diversion of seawater between the main electrolyzer and the sub-electrolyzer according to the preset seawater composition-electrolyzer matching rule, including:

[0084] Based on the degree of influence of various parameters in seawater on electrolysis efficiency, the basic weighting coefficients of each parameter are preset;

[0085] A parameter-electrolysis efficiency sensitivity matrix is ​​constructed using historical electrolysis data. The weight coefficients of each parameter are dynamically adjusted based on the real-time fluctuation range of seawater parameters. When the fluctuation range of a certain parameter exceeds the preset fluctuation threshold, the weight coefficient of that parameter is increased by 20%-50%, while the weight coefficients of other parameters are decreased proportionally.

[0086] The detected parameters are weighted according to the aforementioned basic weighting coefficients. Based on the weighted comprehensive score, the seawater in the main electrolyzer is diverted to the sub-electrolyzer with the highest comprehensive score. Each sub-electrolyzer has a pre-established comprehensive score-optimal electrolysis parameter reference table based on historical data, which is used to determine the electrolysis voltage, current, temperature, and pH value of the corresponding sub-electrolyzer.

[0087] Specifically, the preset fluctuation thresholds are set as follows: sodium chloride concentration fluctuation threshold is ±2g / L, pH value fluctuation threshold is ±0.3, magnesium ion concentration fluctuation threshold is ±5ppm, calcium ion concentration fluctuation threshold is ±3ppm, and bromide ion concentration fluctuation threshold is ±2ppm.

[0088] When the weight coefficient of a certain parameter is adjusted, the weight coefficients of other parameters are redistributed using the following formula:

[0089] Wnew = n -1 Wold ×(1-Δ W );

[0090] in, Wnew These are the weighting coefficients for the other parameters after adjustment. Wold Δ represents the weighting coefficients of other parameters before adjustment. W The weighting coefficients are added to adjust the parameters. n This represents the total number of parameters involved in the calculation.

[0091] In this embodiment, a comprehensive score is calculated based on real-time detected multiple parameters (such as sodium chloride concentration × 0.5 + pH value × 0.3 + magnesium ion concentration × 0.2). Seawater is then diverted to the sub-electrolyzer with the highest score. The weighting coefficients of each parameter are dynamically adjusted according to the sensitivity of electrolysis efficiency. The weighted comprehensive score mechanism avoids frequent switching caused by fluctuations in a single parameter. For example, when the sodium chloride concentration decreases but the pH value remains normal, the concentration factor is given priority, reducing unnecessary diversion operations.

[0092] The following is an example of the matching rules between seawater composition and electrolyzer:

[0093] Step 1: Preset the basic weight coefficients for each parameter:

[0094] The weighting coefficients for sodium chloride concentration and pH value are 0.3, magnesium ion concentration and calcium ion concentration are 0.1, 0.05, and 0.05, respectively.

[0095] Step 2: Dynamic weight calculation (based on real-time fluctuations):

[0096] A decrease in NaCl concentration of 8 g / L (fluctuation threshold ±2 g / L) → increases the weighting coefficient to 0.6;

[0097] pH increases by 1.3 (fluctuation threshold ± 0.3) → weighting coefficient increases to 0.4;

[0098] Magnesium ion / calcium ion / bromine ion fluctuations did not exceed the threshold → the weighting coefficients were proportionally reduced to 0.033, 0.017, and 0.01.

[0099] Step 3: Sub-electrolyzer scoring (ideal parameter difference × weight), such as Figure 4 The table shown is the scoring table for each sub-electrolyte.

[0100] Step 4: Diversion decision: The second sub-electrolyzer has the lowest score (optimal match), so start pumping 3m³ / h of seawater to the corresponding conditioning tank.

[0101] like Figure 2 As shown, in this embodiment, to ensure that each sub-electrolyzer operates within its optimal efficiency range, each sub-electrolyzer is equipped with an independent conditioning tank. The conditioning tank is used to adjust the pH value of the seawater pumped from the main electrolyzer to the corresponding sub-electrolyzer. The conditioning tank includes:

[0102] pH detection unit: Real-time detection of the pH value of seawater pumped into the main electrolyzer.

[0103] Acid-base addition unit: Add hydrochloric acid or sodium hydroxide solution to adjust the pH value according to the preset ideal pH range of the sub-electrolyte.

[0104] Mixing and stirring unit: Uses a propeller-type stirrer with a speed of 100-300 rpm to ensure uniform mixing.

[0105] Intelligent control unit: When the detected pH value differs from the ideal pH value of the sub-electrolyzer by more than ±0.5, the modulation process is triggered; if the difference is ≤ ±0.5, the modulation tank is skipped, and seawater is directly transported to the sub-electrolyzer. Each modulation tank has a volume of 300L-600L, and the pH detection unit includes a pH sensor and an acid / alkali dosing system. The mixing and stirring unit includes a propeller agitator located in the middle of the modulation tank. The following is an example of pH value measurement in the modulation tank:

[0106] The pH of the seawater pumped into the conditioning tank was measured to be 9.3 (the target pH of the conditioning tank is 9.0). At this point, 1.8 L of 0.5 mol / L HCl was added, stirred for 8 minutes, and then transferred to the second sub-electrolyte. The second sub-electrolyte continued electrolysis at 2.9V. After the NaCl concentration dropped to 13 g / L, it was automatically diverted to the third sub-electrolyte for deep electrolysis. If magnesium ions were detected to be >50 ppm (if the fourth sub-electrolyte was activated), the conditioning tank first reduced the magnesium ion concentration to below 10 ppm using an ion exchange column.

[0107] like Figure 5 As shown, in another embodiment, a system 200 for preparing sodium hypochlorite by electrolyzing seawater is provided. The system 200 includes an electrolysis device 201 and a monitoring device 202.

[0108] The electrolysis apparatus 201 includes a main electrolytic cell and two or more sub-electrolytic cells; each of the main electrolytic cell and each sub-electrolytic cell is provided with a positive electrode and a negative electrode, and the electrolysis voltage and current parameters of the main electrolytic cell and each of the sub-electrolytic cells can be dynamically adjusted independently, and the main electrolytic cell is connected to each of the sub-electrolytic cells through different pumping pipes.

[0109] The monitoring device 202 includes a seawater parameter detection module, a diversion control module, and a parameter fine-tuning module;

[0110] The seawater parameter detection module is used to detect the composition and concentration of seawater in the main electrolytic cell and each of the sub-electrolytic cells in real time. The diversion control module, based on the detection results from the seawater parameter detection module, pumps seawater from the main electrolytic cell to the sub-electrolytic cell with the optimal electrolysis parameters for continued electrolysis, while simultaneously replenishing the main electrolytic cell with fresh seawater, dynamically maintaining the composition and concentration of seawater in the main electrolytic cell within a preset range. The parameter fine-tuning module, based on the detection results of the seawater parameters in the main electrolytic cell and each of the sub-electrolytic cells from the seawater parameter detection module, fine-tunes the electrolysis voltage and current parameters in the main electrolytic cell and each of the sub-electrolytic cells to adapt to the seawater parameters in each cell and achieve optimal electrolysis efficiency.

[0111] Furthermore, the diversion control module controls the diversion of seawater between the main electrolyzer and the sub-electrolyzer according to a preset seawater composition-electrolyzer matching rule.

[0112] Finally, it should be noted that although the above embodiments have been described in the text and drawings of this application, this should not limit the scope of patent protection of this application. Any technical solutions that are based on the essential concept of this application and utilize the content described in the text and drawings of this application, resulting in equivalent structural or procedural substitutions or modifications, as well as the direct or indirect application of the technical solutions of the above embodiments to other related technical fields, are all included within the scope of patent protection of this application.

Claims

1. An energy-saving apparatus for preparing sodium hypochlorite by electrolyzing seawater, characterized in that, include: The main electrolytic cell and two or more sub-electrolytic cells are provided; each of the main electrolytic cell and each sub-electrolytic cell is provided with a positive electrode and a negative electrode, and the electrolysis voltage and current parameters of the main electrolytic cell and each of the sub-electrolytic cells can be dynamically adjusted independently, and the main electrolytic cell is connected to each of the sub-electrolytic cells through different pumping pipes; The device for preparing sodium hypochlorite by electrolyzing seawater in an energy-saving manner also includes a seawater parameter detection module, a diversion control module, and a parameter fine-tuning module; The seawater parameter detection module is used to detect the composition and concentration of seawater in the main electrolytic cell and each of the sub-electrolytic cells in real time; The diversion control module is used to pump the seawater in the main electrolysis cell to the sub-electrolysis cell with the optimal electrolysis parameters according to the detection results of the seawater parameter detection module, so as to continue electrolysis, and at the same time replenish the main electrolysis cell with new seawater, so that the composition and concentration of the seawater in the main electrolysis cell are dynamically maintained within a preset range. The parameter fine-tuning module fine-tunes the electrolysis voltage and current parameters in the main electrolytic cell and each of the sub-electrolytic cells based on the detection results of the seawater parameters in the main electrolytic cell and each of the sub-electrolytic cells by the seawater parameter detection module, so as to adapt to the seawater parameters in each cell and achieve the best electrolysis efficiency. The diversion control module controls the diversion of seawater between the main electrolyzer and the sub-electrolyzer according to the preset seawater composition-electrolyzer matching rules; The diversion control module controls the diversion of seawater between the main electrolyzer and the sub-electrolyzer according to a preset seawater composition-electrolyzer matching rule, including: Based on the degree of influence of various parameters in seawater on electrolysis efficiency, the basic weighting coefficients of each parameter are preset; A parameter-electrolysis efficiency sensitivity matrix is ​​constructed using historical electrolysis data. The weight coefficients of each parameter are dynamically adjusted based on the real-time fluctuation range of seawater parameters. When the fluctuation range of a certain parameter exceeds the preset fluctuation threshold, the weight coefficient of that parameter is increased by 20%-50%, while the weight coefficients of other parameters are decreased proportionally. The detected parameters are weighted according to the aforementioned basic weighting coefficients; Based on the weighted comprehensive score, the seawater in the main electrolyzer is diverted to the sub-electrolyzer with the highest comprehensive score. Each sub-electrolyzer has a comprehensive score-optimal electrolysis parameter comparison table established in advance based on historical data, which is used to determine the electrolysis voltage, current, temperature and pH value of the corresponding sub-electrolyzer.

2. The apparatus for preparing sodium hypochlorite by energy-saving electrolysis of seawater according to claim 1, characterized in that, The diversion control module controls the diversion of seawater between the main electrolyzer and the sub-electrolyzer according to a preset seawater composition-electrolyzer matching rule, and also includes: Calculate the actual electrolysis efficiency of each of the sub-electrolytes; The actual electrolysis efficiency of each sub-electrolytic cell is compared with the preset electrolysis efficiency. Based on the comparison results, the weight coefficients in the weight calculation unit and the fluctuation thresholds in the weight dynamic adjustment unit are corrected in reverse to form a closed-loop optimization system.

3. The apparatus for preparing sodium hypochlorite by energy-saving electrolysis of seawater according to claim 1, characterized in that, The seawater parameters include sodium chloride concentration, pH value, magnesium ion concentration, and calcium ion concentration.

4. The apparatus for preparing sodium hypochlorite by energy-saving electrolysis of seawater according to claim 1, characterized in that, The parameter fine-tuning module dynamically adjusts the electrolysis parameters of each electrolyzer through an established mathematical model of electrolysis parameters and seawater parameters.

5. The apparatus for preparing sodium hypochlorite by energy-saving electrolysis of seawater according to claim 1, characterized in that, The electrode surfaces of the main electrolytic cell and each of the sub-electrolytic cells are loaded with catalyst coatings of different compositions to adapt to different seawater compositions and electrolysis parameters; The electrode catalyst of the main electrolyzer uses a ruthenium-iridium-titanium ternary coating, wherein ruthenium: The molar ratio of iridium to titanium is 5:3:2; The electrode catalyst of the first sub-electrolyte uses a ruthenium-iridium-tin coating, wherein the molar ratio of ruthenium:iridium:tin is 4:4:2; The electrode catalyst of the second sub-electrolyte uses a platinum-iridium coating, wherein the molar ratio of platinum to iridium is 7:

3.

6. The apparatus for preparing sodium hypochlorite by energy-saving electrolysis of seawater according to claim 5, characterized in that, Each of the sub-electrolytes is equipped with an independent modulation cell, the modulation cell comprising: pH detection unit: Real-time detection of the pH value of seawater pumped into the main electrolyzer; Acid-base addition unit: pH value is adjusted by adding hydrochloric acid or sodium hydroxide solution according to the preset ideal pH range of the sub-electrolyte; Intelligent control unit: When the detected pH value differs from the ideal pH value of the sub-electrolyzer by more than ±0.5, the modulation process is triggered; if the difference is ≤ ±0.5, the modulation tank is skipped and the seawater is directly transported to the sub-electrolyzer.

7. A system for preparing sodium hypochlorite by electrolyzing seawater in an energy-saving manner, characterized in that, include: An electrolysis apparatus includes: a main electrolytic cell and two or more sub-electrolytic cells; each of the main electrolytic cell and each sub-electrolytic cell is provided with a positive electrode and a negative electrode, and the electrolysis voltage and current parameters of the main electrolytic cell and each of the sub-electrolytic cells can be dynamically adjusted independently, and the main electrolytic cell is connected to each of the sub-electrolytic cells through different pumping pipes; The monitoring device includes a seawater parameter detection module, a diversion control module, and a parameter fine-tuning module; The seawater parameter detection module is used to detect the composition and concentration of seawater in the main electrolytic cell and each of the sub-electrolytic cells in real time; The diversion control module is used to pump the seawater in the main electrolysis cell to the sub-electrolysis cell with the optimal electrolysis parameters according to the detection results of the seawater parameter detection module, so as to continue electrolysis, and at the same time replenish the main electrolysis cell with new seawater, so that the composition and concentration of the seawater in the main electrolysis cell are dynamically maintained within a preset range. The parameter fine-tuning module fine-tunes the electrolysis voltage and current parameters in the main electrolytic cell and each of the sub-electrolytic cells based on the detection results of the seawater parameters in the main electrolytic cell and each of the sub-electrolytic cells by the seawater parameter detection module, so as to adapt to the seawater parameters in each cell and achieve the best electrolysis efficiency. The diversion control module controls the diversion of seawater between the main electrolyzer and the sub-electrolyzer according to a preset seawater composition-electrolyzer matching rule, including: Based on the degree of influence of various parameters in seawater on electrolysis efficiency, the basic weighting coefficients of each parameter are preset; A parameter-electrolysis efficiency sensitivity matrix is ​​constructed using historical electrolysis data. The weight coefficients of each parameter are dynamically adjusted based on the real-time fluctuation range of seawater parameters. When the fluctuation range of a certain parameter exceeds the preset fluctuation threshold, the weight coefficient of that parameter is increased by 20%-50%, while the weight coefficients of other parameters are decreased proportionally. The detected parameters are weighted according to the aforementioned basic weighting coefficients; Based on the weighted comprehensive score, the seawater in the main electrolyzer is diverted to the sub-electrolyzer with the highest comprehensive score. Each sub-electrolyzer has a comprehensive score-optimal electrolysis parameter comparison table established in advance based on historical data, which is used to determine the electrolysis voltage, current, temperature and pH value of the corresponding sub-electrolyzer.

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