Power-saving device and system for preparing sodium hypochlorite by electrolyzing seawater

Abstract

The invention discloses an electricity-saving device and system for preparing sodium hypochlorite by electrolyzing seawater, the electricity-saving device comprises a main electrolytic bath and more than two sub-electrolytic baths, a shunt control module is used for pumping seawater in the main electrolytic bath into the sub-electrolytic bath with the best corresponding electrolysis parameter for continuous electrolysis according to the detection result of a seawater parameter detection module, and the seawater is electrolyzed in the sub-electrolytic bath according to the detection result of the seawater parameter detection module. And meanwhile, new seawater is supplemented into the main electrolytic cell, so that the components and the concentration of the seawater in the main electrolytic cell are dynamically maintained in a preset range. According to the technical scheme, double optimization of energy consumption and side reaction is realized through multi-stage electrolytic cells, dynamic parameter regulation and control and catalyst customization. Optimal electrolysis parameters are set in different tank bodies according to the difference of seawater components, so that the comprehensive energy consumption can be reduced; by inhibiting magnesium hydroxide precipitation, oxygen evolution reaction and bromide interference, the side reaction occurrence rate is reduced, meanwhile, the service life of an electrode is prolonged, the sodium hypochlorite yield is increased, and the electrolytic efficiency and economic benefits are remarkably improved.

Description

Technical Field

[0001] The present application relates to the field of seawater electrolysis, and particularly to a device and system for preparing sodium hypochlorite by power-saving electrolysis of seawater. Background Art

[0002] Sodium hypochlorite is widely used in the industrial field and has become an indispensable chemical due to its strong oxidizing property. In the water treatment industry, as an efficient bactericide and disinfectant, it can quickly inactivate bacteria and viruses, and remove algae and odors in water; in textile printing and dyeing, it is used for bleaching cotton and linen fabrics to improve whiteness and dyeing effect; in the paper industry, it can oxidize lignin to achieve pulp bleaching; in addition, it is also commonly used in industrial wastewater treatment to degrade toxic pollutants such as phenols and cyanides, and as a bactericide for reinjection water in oil fields to prevent microbial corrosion of pipelines.

[0003] The main preparation methods of sodium hypochlorite are electrolysis method, chemical method and double decomposition method. Among them, the electrolysis method is the industrial mainstream. By electrolyzing sodium chloride solution to generate sodium chlorate, it has the advantages of large output, high purity (≥98%), mature process, etc., and is suitable for large-scale production, but it has the disadvantages of high energy consumption, large equipment investment and the risk of hydrogen explosion; the chemical method uses the alkaline disproportionation of sodium chlorate or the high-temperature reaction of chlorine and sodium hydroxide to prepare, with simple process and easy-to-obtain raw materials, suitable for small-scale or laboratory scenarios, but the product purity is low and there are many side reactions; the double decomposition method generates sodium chlorate by the reaction of sodium perchlorate and potassium chloride, and has very little industrial application due to high raw material cost and difficult separation. At present, the electrolysis method occupies more than 90% of the industrial production capacity due to its efficiency and purity advantages, and reducing energy consumption and equipment cost is its main optimization direction.

[0004] The core of preparing sodium hypochlorite by electrolyzing seawater is to use the electrolysis reaction to convert NaCl in seawater into chlorine and NaOH, and the two react to generate NaClO. The process difficulty lies in the pretreatment of seawater impurities and the control of electrolysis conditions. Among them, the salinity, pH value of seawater and the electrolysis temperature will all affect the electrolysis efficiency. If the seawater salinity is too low (such as coastal seawater), the concentration of chloride ions will be reduced, resulting in a decrease in electrolysis efficiency; if it is too high, the energy consumption will increase. Chlorine is volatile under acidic conditions of seawater, and the formation of hypochlorite ions is promoted under alkaline conditions, but when pH>10, the hypochlorite ions are easily decomposed. Increasing the electrolysis temperature can promote the reaction of chlorine and hydroxide ions, but when it exceeds 40°C, the decomposition of hypochlorite ions will be accelerated.

[0005] Moreover, seawater also contains ions such as magnesium ions, calcium ions, and sulfate ions, which may all cause side reactions. Among them, magnesium ions react with hydroxide ions to form magnesium hydroxide precipitation, which may block the electrodes or affect the electrolysis efficiency; bromide ions may be oxidized, affecting the purity of NaClO, and need to be controlled through pretreatment. Therefore, how to efficiently electrolyze and prepare sodium hypochlorite is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] In view of the above problems, the present application provides a device for preparing sodium hypochlorite by power-saving electrolysis of seawater, which is used to solve 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 object, the present application provides a device for preparing sodium hypochlorite by power-saving electrolysis of seawater, including: a main electrolytic cell and more than two sub-electrolytic cells; positive electrodes and negative electrodes are arranged in both the main electrolytic cell and each sub-electrolytic cell, and the electrolysis voltage and current parameters of the main electrolytic cell and each sub-electrolytic cell can be adjusted dynamically separately, and the main electrolytic cell is respectively connected to each sub-electrolytic cell through different pumping pipelines; The device for preparing sodium hypochlorite by power-saving electrolysis of seawater further includes a seawater parameter detection module, a flow 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 sub-electrolytic cell in real time; The flow control module is used to pump the seawater in the main electrolytic cell into the sub-electrolytic cell with the best corresponding electrolysis parameters for continuous electrolysis according to the detection result of the seawater parameter detection module, and at the same time supplement new seawater into the main electrolytic cell to keep the composition and concentration of the seawater in the main electrolytic cell dynamically within a preset range; The parameter fine-tuning module fine-tunes the electrolysis voltage and current parameters in the main electrolytic cell and each electrolytic cell according to the detection results of the seawater parameter detection module on the seawater parameters in the main electrolytic cell and each sub-electrolytic cell, so as to adapt to the seawater parameters in each cell to achieve the best electrolysis efficiency.

[0008] Further, the flow control module controls the flow of seawater between the main electrolytic cell and the sub-electrolytic cells according to a preset seawater composition - electrolytic cell matching rule.

[0009] Further, the flow control module controls the flow of seawater between the main electrolytic cell and the sub-electrolytic cells according to a preset seawater composition - electrolytic cell matching rule, including: Preset the basic weight coefficients of each parameter according to the influence degree of each parameter in seawater on the electrolysis efficiency; Construct a parameter - electrolysis efficiency sensitivity matrix through historical electrolysis data, and dynamically adjust the weight coefficients of each parameter according to the fluctuation range of the seawater parameters detected in real time; when the fluctuation range of a certain parameter exceeds the preset fluctuation threshold, increase the weight coefficient of this parameter by 20% - 50%, and at the same time reduce the weight coefficients of other parameters in equal proportion; Perform weighted calculation on each detected parameter according to the basic weight coefficient; According to the comprehensive score calculated by weighting, the seawater in the main electrolytic cell is diverted to the sub-electrolytic cell with the highest comprehensive score; among them, a comprehensive score - optimal electrolysis parameter comparison table is established for each sub-electrolytic cell in advance according to historical data, which is used to determine the electrolysis voltage, current, temperature and pH value of the corresponding sub-electrolytic cell.

[0010] Further, the diversion control module controls the diversion of seawater between the main electrolytic cell and the sub-electrolytic cells according to the preset seawater composition - electrolytic cell matching rules, and further includes: Calculating the actual electrolysis efficiency of each of the sub-electrolytic cells; Comparing the actual electrolysis efficiency of each of the sub-electrolytic cells with the preset electrolysis efficiency, and reversely correcting the weight coefficient in the weight calculation unit and the fluctuation threshold in the weight dynamic adjustment unit according to the comparison result to form a closed-loop optimization system.

[0011] Further, the seawater parameters include but are not limited to sodium chloride concentration, pH value, magnesium ion concentration, and calcium ion concentration.

[0012] Further, the parameter fine-tuning module dynamically adjusts the electrolysis parameters of each electrolytic cell through the established electrolysis parameter - seawater parameter mathematical model.

[0013] Further, the electrode surfaces in the main electrolytic cell and each of the sub-electrolytic cells are loaded with catalyst coatings with different compositions to adapt to different seawater compositions and electrolysis parameters; The electrode catalyst of the main electrolytic cell adopts a ruthenium-iridium-titanium ternary coating, in which the molar ratio of ruthenium:iridium:titanium is 5:3:2; The electrode catalyst of the first sub-electrolytic cell adopts a ruthenium-iridium-tin coating, in which the molar ratio of ruthenium:iridium:tin is 4:4:2; The electrode catalyst of the second sub-electrolytic cell adopts a platinum-iridium coating, in which the molar ratio of platinum:iridium is 7:3.

[0014] Further, each of the sub-electrolytic cells is equipped with an independent modulation tank, and the modulation tank includes: pH detection unit: real-time detection of the pH value of the seawater pumped into from the main electrolytic cell; Acid-base addition unit: adding hydrochloric acid or sodium hydroxide solution for pH value modulation according to the preset ideal pH value range of the sub-electrolytic cell; Intelligent control unit: when the detected pH value deviates from the ideal pH value of the sub-electrolytic cell by more than ±0.5, triggering the modulation process; if the deviation ≤ ±0.5, skipping the modulation tank and directly transporting the seawater to the sub-electrolytic cell.

[0015] To solve the above technical problems, the present application also provides another technical solution: A power-saving electrolytic seawater system for preparing sodium hypochlorite, comprising: An electrolysis device, comprising: a main electrolysis cell and more than two sub-electrolysis cells; positive electrodes and negative electrodes are arranged in both the main electrolysis cell and each sub-electrolysis cell, and the electrolysis voltage and current parameters of the main electrolysis cell and each sub-electrolysis cell can be dynamically adjusted separately, and the main electrolysis cell is connected to each sub-electrolysis cell through different pumping pipelines; A monitoring device, comprising a seawater parameter detection module, a flow 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 electrolysis cell and each sub-electrolysis cell in real time; The flow control module is used to pump the seawater in the main electrolysis cell into the sub-electrolysis cell with the best corresponding electrolysis parameters for continuous electrolysis according to the detection results of the seawater parameter detection module, and at the same time supplement new seawater into the main electrolysis cell to keep the composition and concentration of the seawater in the main electrolysis cell dynamically within a preset range; The parameter fine-tuning module fine-tunes the electrolysis voltage and current parameters in the main electrolysis cell and each electrolysis cell according to the detection results of the seawater parameter detection module on the seawater parameters in the main electrolysis cell and each sub-electrolysis cell, so as to adapt to the seawater parameters in each cell to achieve the best electrolysis efficiency.

[0016] Further, the flow control module controls the flow of seawater between the main electrolysis cell and the sub-electrolysis cells according to a preset seawater composition - electrolysis cell matching rule.

[0017] Different from the prior art, the above-mentioned device and system for electrolyzing seawater to prepare sodium hypochlorite includes a main electrolysis cell and more than two sub-electrolysis cells. The flow control module is used to pump the seawater in the main electrolysis cell into the sub-electrolysis cell with the best corresponding electrolysis parameters for continuous electrolysis according to the detection results of the seawater parameter detection module, and at the same time supplement new seawater into the main electrolysis cell to keep the composition and concentration of the seawater in the main electrolysis cell dynamically within a preset range; in this technical solution, through multi-stage electrolysis cells, dynamic parameter regulation and customized catalysts, dual optimization of energy consumption and side reactions is achieved. By setting the best electrolysis parameters in different cell bodies according to the differences in seawater composition, the comprehensive energy consumption can be reduced; by inhibiting the precipitation of magnesium hydroxide, oxygen evolution reaction and bromide interference, the incidence rate of side reactions is reduced by more than [X], and at the same time the electrode life is extended by more than [X], the yield of sodium hypochlorite is increased, and the electrolysis efficiency and economic benefits are significantly improved.

[0018] The above description of the invention content is only an overview of the technical solution of this application. In order to enable those of ordinary skill in the art to understand the technical solution of this application more clearly, and then to implement it according to the content recorded in the description and the drawings, and in order to make the above-mentioned objects, other objects, features and advantages of this application more easily understood, the following is described in conjunction with the specific implementation manners and drawings of this application. Description of the Drawings

[0019] The drawings are only used to illustrate the principles, implementation methods, applications, features, and effects of the specific embodiments of the present invention and other related contents, and should not be considered as a limitation to this application.

[0020] In the drawings of the specification: Figure 1 is a block diagram of the device for preparing sodium hypochlorite by power-saving electrolysis of seawater described in the specific embodiment; Figure 2 is a schematic connection diagram of the main electrolytic cell and the sub-electrolytic cell described in the specific embodiment; Figure 3 is a data comparison table of the device for preparing sodium hypochlorite described in the specific embodiment and traditional equipment; Figure 4 is a scoring table of the sub-electrolytic cell described in the specific embodiment; Figure 5 is a block diagram of the system for preparing sodium hypochlorite by power-saving electrolysis of seawater described in the specific embodiment; The descriptions of the reference numerals involved in the above-mentioned drawings are as follows: 100, device for preparing sodium hypochlorite by power-saving electrolysis of seawater; 1, main electrolytic cell; 11, electrode assembly; 2, sub-electrolytic cell; 22, modulation tank; 3, seawater parameter detection module; 4, shunt control module; 5, parameter fine-tuning module; 200, system for preparing sodium hypochlorite by power-saving electrolysis of seawater; 201, electrolysis device; 202, monitoring device; Specific Embodiment

[0021] To describe in detail the possible application scenarios, technical principles, implementable specific solutions, achievable purposes and effects, etc. of this application, the following will be described in detail in combination with the listed specific embodiments and with reference to the drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of this application, so they are only examples and cannot be used to limit the protection scope of this application.

[0022] Referring to "embodiment" in this article means that the specific features, structures or characteristics described in combination with the embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various positions in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in this application, as long as there is no technical contradiction or conflict, the technical features mentioned in each embodiment can be combined in any way to form the corresponding implementable technical solutions.

[0023] Unless otherwise defined, the meanings of the technical terms used herein are the same as those commonly understood by those skilled in the technical field to which this application belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit this application.

[0024] In the description of this application, the term "and / or" is an expression used to describe the logical relationship between objects, indicating that there can be three relationships. For example, A and / or B means: the existence of A, the existence of B, and the simultaneous existence of both A and B. In addition, the character " / " herein generally represents an "or" logical relationship between the associated objects before and after.

[0025] In this application, terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantitative, primary-secondary, or sequential relationship between these entities or operations.

[0026] Without further limitation, in this application, the open-ended expressions such as "comprising", "including", "having", or other similar expressions used in the statements are intended to cover non-exclusive inclusion. These expressions do not exclude the possibility that there may be additional elements in the process, method, or product including the said elements, such that the process, method, or product including a series of elements may not only include those defined elements, but also include other elements not explicitly listed, or elements inherent to such process, method, or product.

[0027] Similar to the understanding in the "Examination Guidelines", in this application, expressions such as "greater than", "less than", "exceeding", etc. are understood not to include the number itself; expressions such as "above", "below", "within", etc. are understood to include the number itself. In addition, in the description of the embodiments of this application, the meaning of "a plurality of" is two or more (including two), and similar expressions related to "multiple" are understood in the same way, such as "multiple groups", "multiple times", etc., unless otherwise specifically defined.

[0028] In the description of the embodiments of this application, the spatially related expressions used, such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "perpendicular", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiment or the drawing. It is only for the convenience of describing the specific embodiments of this application or for the reader's understanding, and does 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, it should not be construed as a limitation on the embodiments of this application.

[0029] Unless otherwise clearly specified or defined, in the description of the embodiments of the present application, terms such as "installation", "connection", "linkage", "fixation", "setting", etc. shall be understood in a broad sense. For example, the "connection" may be a fixed connection, a detachable connection, or an integral setting; it may be a mechanical connection, an electrical connection, or a communication connection; it may be a direct connection or an indirect connection through an intermediate medium; it may be the communication inside two components or the interaction relationship between two components. For those skilled in the art to which the present application pertains, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0030] Please refer to Figure 1 , this embodiment provides a device 100 for preparing sodium hypochlorite by power-saving electrolysis of seawater. The device 100 for preparing sodium hypochlorite by power-saving electrolysis of seawater prepares sodium hypochlorite by electrolyzing seawater. The device 100 for preparing sodium hypochlorite by power-saving electrolysis of seawater includes: a main electrolytic cell 1 and more than two sub-electrolytic cells 2, a seawater parameter detection module 3, a flow control module 4, and a parameter fine-tuning module 5.

[0031] As Figure 2 shown, in this embodiment, it is a connection schematic diagram of the main electrolytic cell and the sub-electrolytic cells. Among them, electrode assemblies 11 are provided in both the main electrolytic cell 1 and each sub-electrolytic cell 2, and the electrode assembly includes a positive electrode and a negative electrode arranged oppositely. And the electrolysis voltage and current parameters of the main electrolytic cell and each sub-electrolytic cell can be dynamically adjusted separately, and the main electrolytic cell is respectively connected to each sub-electrolytic cell through different pumping pipelines. In the main electrolytic cell and each sub-electrolytic cell, the NaCl in seawater is converted into chlorine and sodium hydroxide by electrolysis reaction, and the two react to generate sodium hypochlorite, but only the electrolysis parameter settings of each electrolytic cell are different, so that the main electrolytic cell can operate in the optimal electrolysis efficiency section.

[0032] The seawater parameter detection module 3 is used to detect the composition and concentration of seawater in the main electrolytic cell and each sub-electrolytic cell 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 flow control module 4 is used to pump the seawater in the main electrolytic cell into the sub-electrolytic cell with the best corresponding electrolysis parameters for continuous electrolysis according to the detection results of the seawater parameter detection module, and at the same time supplement new seawater into the main electrolytic cell to keep the composition and concentration of the seawater in the main electrolytic cell dynamically within a preset range. The parameter fine-tuning module 5 fine-tunes the electrolysis voltage and current parameters in the main electrolytic cell and each electrolytic cell according to the detection results of the seawater parameter detection module on the seawater parameters in the main electrolytic cell and each sub-electrolytic cell, so as to adapt to the seawater parameters in each cell to achieve the best electrolysis efficiency.

[0033] In this embodiment, the main electrolytic cell 1 is the main equipment for seawater electrolysis. The volume of the main electrolytic cell 1 can be 8 - 15 m³, and the volume of the sub - electrolytic cell 2 is smaller than that of the main electrolytic cell 1. The volume of the sub - electrolytic cell 2 can be 5 - 8 m³. In this embodiment, as Figure 2 shown, in this embodiment, three sub - electrolytic cells are provided, which are respectively used for electrolyzing seawater with different NaCl concentrations.

[0034] Schematically, the first sub - electrolytic cell is used for electrolyzing seawater with a NaCl concentration > 30 g / L (i.e., medium - high - concentration seawater), the second electrolytic cell is used for electrolyzing seawater with a NaCl concentration of 15 - 30 g / L (i.e., medium - concentration seawater); the third electrolytic cell is used for electrolyzing seawater with a NaCl concentration < 15 g / L (i.e., low - concentration seawater).

[0035] In order to adapt to different seawater compositions and electrolysis parameters, catalyst coatings with different compositions are loaded on the electrode surfaces in the main electrolytic cell and each of the sub - electrolytic cells.

[0036] The electrode catalyst of the main electrolytic cell uses a ruthenium - iridium - titanium ternary coating, that is, a ruthenium - iridium - titanium ternary coating (with a thickness of 4 μm) is provided on the positive electrode surface, where the molar ratio of ruthenium: iridium: titanium is 5:3:2; the negative electrode uses a nickel - based electrode. The designed current density of the main electrolytic cell is 3500 A / m², and the temperature is 78 °C. And a multi - parameter on - line detector is equipped in the main electrolytic cell to be used for real - time detection of sodium chloride concentration (accuracy ±0.5 g / L), pH value (±0.02), magnesium ions (±2 ppm), calcium ions (±1 ppm), bromide ions (±0.5 ppm).

[0037] The electrode catalyst of the first sub - electrolytic cell uses a ruthenium - iridium - tin coating, that is, a ruthenium - iridium - tin coating is provided on the positive electrode surface, where the molar ratio of ruthenium: iridium: tin is 4:4:2; the preset current density of the first sub - electrolytic cell is 3000 A / m², and pH = 8.2.

[0038] The electrode catalyst of the second sub - electrolytic cell uses a platinum - iridium coating, that is, a platinum - iridium coating is provided on the positive electrode surface, where the molar ratio of platinum: iridium is 7:3. The preset current density of the second sub - electrolytic cell is 2200 A / square meter, and pH = 9.0.

[0039] The third sub - electrolytic cell uses a manganese dioxide - modified titanium - based electrode, with a current density of 1500 A / m² and a temperature of 45 °C.

[0040] In the main electrolysis stage: Seawater enters the main electrolytic cell at a preset flow rate, for example, a flow rate of 15 m³ / h. The initial parameters of the seawater are: sodium chloride 32 g / L, pH 8.0, magnesium ions 55 ppm, calcium ions 12 ppm.

[0041] After electrolyzing in the main electrolytic cell for a certain period of time (e.g., 25 minutes) at a set voltage (e.g., 3.4 V), the detector detects the real-time data of seawater: NaCl = 24 g / L, pH = 9.3, magnesium ions = 48 ppm, calcium ions = 10 ppm. Then, according to the preset matching rule of seawater composition - electrolytic cell, the control system controls the seawater to enter the corresponding sub-electrolytic cell from the main electrolytic cell for further electrolysis.

[0042] In this embodiment, the shunt control module controls the shunt of seawater between the main electrolytic cell and the sub-electrolytic cells according to the preset matching rule of seawater composition - electrolytic cell, and further includes: Calculating the actual electrolysis efficiency of each sub-electrolytic cell; Comparing the actual electrolysis efficiency of each sub-electrolytic cell with the preset electrolysis efficiency, and reversely correcting the weight coefficient in the weight calculation unit and the fluctuation threshold in the weight dynamic adjustment unit according to the comparison result to form a closed-loop optimization system.

[0043] The parameter fine-tuning module dynamically adjusts the electrolysis parameters of each electrolytic cell through the established mathematical model of electrolysis parameters - seawater parameters.

[0044] As Figure 2 shown, in this embodiment, each sub-electrolytic cell 2 is equipped with an independent modulation tank 22. The modulation tank includes: pH detection unit: Real-time detection of the pH value of the seawater pumped into the sub-electrolytic cell from the main electrolytic cell; Acid-base addition unit: Adding hydrochloric acid or sodium hydroxide solution for pH value modulation according to the preset ideal pH value range of the sub-electrolytic cell; Intelligent control unit: When the detected pH value deviates from the ideal pH value of the sub-electrolytic cell by more than ±0.5, triggering the modulation process; if the deviation ≤ ±0.5, skipping the modulation tank and directly transporting the seawater to the sub-electrolytic cell.

[0045] In the prior art, during the electrolysis of seawater, the key components in seawater (such as NaCl concentration, magnesium ions, calcium ion impurity content, pH value) change significantly with the reaction process. In the initial stage of electrolysis, the NaCl concentration in seawater is relatively high (about 3.5%), which is suitable for rapid chlorine production at a high current density, but impurity ions (such as magnesium ions) are likely to form precipitates under alkaline conditions and block the electrodes. In the later stage of electrolysis, the NaCl concentration decreases and the hydroxide concentration increases. If the original parameters are maintained, it will lead to an increase in cell voltage and a sharp increase in energy consumption.

[0046] In this embodiment, a main electrolytic cell 1 and more than two sub-electrolytic cells 2 are provided. The shunt control module 4 is configured to pump the seawater in the main electrolytic cell 1 into the sub-electrolytic cell 2 with the best corresponding electrolysis parameters for continuous electrolysis according to the detection results of the seawater parameter detection module, and at the same time supplement new seawater into the main electrolytic cell 1 to dynamically maintain the composition and concentration of the seawater in the main electrolytic cell within a preset range. In this embodiment, by dynamically adjusting parameters in separate cells (for example, the first sub-electrolytic cell uses a high current density for medium and high concentration seawater, and the second sub-electrolytic cell uses low temperature + low voltage for low concentration seawater), the overall electrolysis efficiency can be improved and the electrolysis energy consumption can be reduced. In this technical solution, through a multi-stage electrolytic cell, dynamic parameter regulation, and customized catalysts, dual optimization of energy consumption and side reactions is achieved. As Figure 3 shown, by setting the best electrolysis parameters in different cell bodies according to the differences in seawater composition, the comprehensive energy consumption can be reduced; by suppressing magnesium hydroxide precipitation, oxygen evolution reaction, and bromide interference, the incidence rate of side reactions can be reduced by more than [X], and at the same time, the electrode life can be extended by more than [X], the sodium hypochlorite yield can be increased, and the electrolysis efficiency and economic benefits can be significantly improved.

[0047] The shunt control module controls the shunt of seawater between the main electrolytic cell and the sub-electrolytic cell according to a preset seawater composition - electrolytic cell matching rule. The shunt control module controls the shunt of seawater between the main electrolytic cell and the sub-electrolytic cell according to a preset seawater composition - electrolytic cell matching rule, including: Presetting the basic weight coefficients of each parameter according to the influence degree of each parameter in seawater on the electrolysis efficiency; Constructing a parameter - electrolysis efficiency sensitivity matrix through historical electrolysis data, and dynamically adjusting the weight coefficients of each parameter according to the fluctuation range of the seawater parameters detected in real time; when the fluctuation range of a certain parameter exceeds the preset fluctuation threshold, the weight coefficient of this parameter is increased by 20% - 50%, and at the same time, the weight coefficients of other parameters are reduced proportionally.

[0048] Performing weighted calculation on each detected parameter according to the basic weight coefficients. According to the comprehensive score after weighted calculation, the seawater in the main electrolytic cell is shunted to the sub-electrolytic cell with the highest comprehensive score; among them, a comprehensive score - optimal electrolysis parameter comparison table is established for each sub-electrolytic cell in advance according to historical data, which is used to determine the electrolysis voltage, current, temperature, and pH value of the corresponding sub-electrolytic cell.

[0049] Among them, the preset fluctuation threshold is specifically set as follows: the sodium chloride concentration fluctuation threshold is ±2 g / L, the pH value fluctuation threshold is ±0.3, the magnesium ion concentration fluctuation threshold is ±5 ppm, the calcium ion concentration fluctuation threshold is ±3 ppm, and the bromide ion concentration fluctuation threshold is ±2 ppm.

[0050] When the weight coefficient of a certain parameter is adjusted, the weight coefficients of other parameters are redistributed through the following formula: Wnew = n -1 Wold ×(1 - Δ W ); Wherein, Wnew is the weight coefficient of other parameters after adjustment, Wold is the weight coefficient of other parameters before adjustment, and Δ W is the increased weight coefficient of the adjusted parameter, n is the total number of parameters participating in the calculation.

[0051] In this embodiment, based on the real-time detection of multiple parameters (such as sodium chloride concentration × 0.5 + pH value × 0.3 + magnesium ion concentration × 0.2), the comprehensive score is calculated, and the seawater is diverted to the sub-electrolytic cell with the highest score. The weight coefficients of each parameter are dynamically adjusted according to the sensitivity of the electrolysis efficiency. Among them, the weighted comprehensive score mechanism is adopted to avoid frequent switching caused by the fluctuation of a single parameter. For example, when the sodium chloride concentration decreases but the pH value is normal, the concentration factor is given priority, reducing unnecessary diversion operations.

[0052] The following is an example of the seawater composition - electrolytic cell matching rule: Step 1: Preset the basic weight coefficients of each parameter: The weight coefficient of sodium chloride concentration is 0.5, the weight coefficient of pH value is 0.3, the weight coefficient of magnesium ion concentration is 0.1, the weight coefficient of calcium ion concentration is 0.05, and the weight coefficient of bromide ion concentration is 0.05.

[0053] Step 2: Dynamic weight calculation (based on real-time fluctuations): The NaCl concentration drops by 8 g / L (fluctuation threshold ±2 g / L) → the weight coefficient is increased to 0.6; The pH rises by 1.3 (fluctuation threshold ±0.3) → the weight coefficient is increased to 0.4; The fluctuations of magnesium ions / calcium ions / bromide ions do not exceed the threshold → the weight coefficients are proportionally reduced to 0.033, 0.017, 0.01.

[0054] Step 3: Score the sub-electrolytic cells (ideal parameter difference × weight). As Figure 4 shown, it is the score table of each sub-electrolytic cell; Step 4: Diversion decision: The second sub-electrolytic cell has the lowest score (optimal match), and start pumping 3 m³ / h of seawater to the corresponding modulation tank.

[0055] As Figure 2 shown, in this embodiment, in order to enable each sub-electrolytic cell to work in its best efficiency range, each of the sub-electrolytic cells is equipped with an independent modulation tank, and the modulation tank is used to adjust the pH value of the seawater pumped from the main electrolytic cell to the corresponding sub-electrolytic cell. The modulation tank includes: pH Detection Unit: It detects the pH value of the seawater pumped into the main electrolytic cell in real time.

[0056] Acid-Base Addition Unit: According to the preset ideal pH value range of the sub-electrolytic cell, hydrochloric acid or sodium hydroxide solution is added for pH value modulation.

[0057] Mixing and Stirring Unit: It uses a propeller agitator with a rotation speed of 100 - 300 rpm to ensure uniform modulation.

[0058] Intelligent Control Unit: When the detected pH value deviates from the ideal pH value of the sub-electrolytic cell by more than ±0.5, the modulation process is triggered; if the deviation ≤ ±0.5, the seawater is directly transported to the sub-electrolytic cell, skipping the modulation tank. Among them, the volume of each modulation tank is 300L - 600L, and the pH detection unit includes a pH sensor and an acid-base dosing system. The mixing and stirring unit includes a propeller stirrer arranged in the middle of the modulation tank. The following is an example of pH value modulation in the modulation tank: The modulation tank detects that the pH of the pumped seawater is 9.3 (the target pH of this modulation tank is 9.0). At this time, it is calculated that 1.8L of 0.5mol / L HCl is added, and after stirring for 8 minutes, it is transported to the second sub-electrolytic cell. The second sub-electrolytic cell continues electrolysis at a voltage of 2.9V. After the NaCl concentration drops to 13g / L, it is automatically diverted to the third sub-electrolytic cell for deep electrolysis. If it is detected that the magnesium ion > 50ppm (such as when the fourth sub-electrolytic cell is enabled), the modulation tank first reduces the magnesium ion to below 10ppm through an ion exchange column.

[0059] As Figure 5 shown, in another embodiment, a system 200 for preparing sodium hypochlorite by power-saving electrolysis of seawater is provided. The system 200 for preparing sodium hypochlorite by power-saving electrolysis of seawater includes: an electrolysis device 201 and a monitoring device 202.

[0060] The electrolysis device 201 includes: a main electrolytic cell and more than two sub-electrolytic cells; positive electrodes and negative electrodes are arranged in both the main electrolytic cell and each sub-electrolytic cell, and the electrolysis voltage and current parameters of the main electrolytic cell and each sub-electrolytic cell can be adjusted dynamically separately, and the main electrolytic cell is respectively connected to each sub-electrolytic cell through different pumping pipelines.

[0061] The monitoring device 202 includes a seawater parameter detection module, a flow 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 flow control module is used to pump the seawater in the main electrolytic cell into the sub-electrolytic cell with the best corresponding electrolysis parameters for continuous electrolysis according to the detection results of the seawater parameter detection module, and at the same time supplement new seawater into the main electrolytic cell, so that the composition and concentration of the seawater in the main electrolytic 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 electrolytic cells according to the detection results of the seawater parameter detection module on the seawater parameters in the main electrolytic cell and each of the sub-electrolytic cells, so as to adapt to the seawater parameters in each cell to achieve the best electrolysis efficiency.

[0062] Further, the flow control module controls the flow of seawater between the main electrolytic cell and the sub-electrolytic cells according to a preset seawater composition-electrolytic cell matching rule.

[0063] Finally, it should be noted that although the above embodiments have been described in the text and drawings of the specification of the present application, the patent protection scope of the present application cannot be limited thereby. Any technical solutions obtained by equivalent structure or equivalent process substitution or modification using the content recorded in the text and drawings of the specification of the present application based on the essential concept of the present application, as well as the technical solutions of the above embodiments directly or indirectly implemented in other related technical fields, are all included in the patent protection scope of the present application.

Claims

1. An apparatus for preparing sodium hypochlorite by electrolyzing seawater with power saving, characterized in that Comprising: A main electrolytic cell and more than two sub-electrolytic cells; positive electrodes and negative electrodes are provided in both the main electrolytic cell and each sub-electrolytic cell, and the electrolysis voltage and current parameters of the main electrolytic cell and each sub-electrolytic cell can be adjusted dynamically separately, and the main electrolytic cell is connected to each sub-electrolytic cell through different pumping pipelines; The device for preparing sodium hypochlorite by saving electricity and electrolyzing seawater further includes a seawater parameter detection module, a shunt 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 sub-electrolytic cell in real time; The shunt control module is used to pump the seawater in the main electrolytic cell into the sub-electrolytic cell with the best corresponding electrolysis parameters for continuous electrolysis according to the detection results of the seawater parameter detection module, and at the same time supplement new seawater into the main electrolytic cell to keep the composition and concentration of the seawater in the main electrolytic cell dynamically within a preset range; The parameter fine-tuning module fine-tunes the electrolysis voltage and current parameters in the main electrolytic cell and each electrolytic cell according to the detection results of the seawater parameters in the main electrolytic cell and each sub-electrolytic cell by the seawater parameter detection module to adapt to the seawater parameters in each cell to achieve the best electrolysis efficiency.

2. The device for preparing sodium hypochlorite by electrolyzing seawater with power saving according to claim 1, characterized in that, The shunt control module controls the shunt of seawater between the main electrolytic cell and the sub-electrolytic cells according to a preset seawater composition - electrolytic cell matching rule.

3. The device for preparing sodium hypochlorite by electrolyzing seawater with power saving according to claim 2, characterized in that, The shunt control module controls the shunt of seawater between the main electrolytic cell and the sub-electrolytic cells according to a preset seawater composition - electrolytic cell matching rule, including: Presetting the basic weight coefficients of each parameter according to the influence degree of each parameter in seawater on the electrolysis efficiency; Constructing a parameter - electrolysis efficiency sensitivity matrix through historical electrolysis data, and dynamically adjusting the weight coefficients of each parameter according to the fluctuation amplitude of the seawater parameters detected in real time; when the fluctuation amplitude of a certain parameter exceeds the preset fluctuation threshold, increasing the weight coefficient of this parameter by 20% - 50%, and at the same time reducing the weight coefficients of other parameters proportionally; Performing weighted calculation on each detected parameter according to the basic weight coefficient; According to the comprehensive score after weighted calculation, shunting the seawater in the main electrolytic cell to the sub-electrolytic cell with the highest comprehensive score; among them, each sub-electrolytic cell has a comprehensive score - optimal electrolysis parameter comparison table established in advance according to historical data for determining the electrolysis voltage, current, temperature and pH value of the corresponding sub-electrolytic cell.

4. The device for preparing sodium hypochlorite by electrolyzing seawater with power saving according to claim 3, characterized in that, The shunt control module controls the shunt of seawater between the main electrolytic cell and the sub-electrolytic cells according to a preset seawater composition - electrolytic cell matching rule, and further includes: Calculating the actual electrolysis efficiency of each sub-electrolytic cell; Comparing the actual electrolysis efficiency of each sub-electrolytic cell with the preset electrolysis efficiency, and reversely correcting the weight coefficients in the weight calculation unit and the fluctuation threshold in the weight dynamic adjustment unit according to the comparison result to form a closed-loop optimization system.

5. The device for preparing sodium hypochlorite by electrolyzing seawater with power saving according to claim 1, characterized in that, The seawater parameters include but are not limited to sodium chloride concentration, pH value, magnesium ion concentration, calcium ion concentration.

6. The device for preparing sodium hypochlorite by electrolyzing seawater with power saving according to claim 1, characterized in that, The parameter fine-tuning module dynamically adjusts the electrolysis parameters of each electrolytic cell through the established electrolysis parameter - seawater parameter mathematical model.

7. The device for preparing sodium hypochlorite by electrolyzing seawater with power saving according to claim 1, wherein The electrode surfaces in 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 electrolytic cell uses a ruthenium-iridium-titanium ternary coating, where ruthenium: iridium:titanium has a molar ratio of 5:3:2; The electrode catalyst of the first sub-electrolytic cell uses a ruthenium-iridium-tin coating, where ruthenium:iridium:tin has a molar ratio of 4:4:2; The electrode catalyst of the second sub-electrolytic cell uses a platinum-iridium coating, where platinum:iridium has a molar ratio of 7:

3.

8. The device for preparing sodium hypochlorite by electrolyzing seawater with power saving according to claim 7, characterized in that, Each of the sub-electrolytic cells is equipped with an independent modulation tank, and the modulation tank includes: pH detection unit: Real-time detection of the pH value of the seawater pumped into the main electrolytic cell; Acid-base addition unit: Adding hydrochloric acid or sodium hydroxide solution for pH value modulation according to the preset ideal pH value range of the sub-electrolytic cell; Intelligent control unit: When the detected pH value deviates from the ideal pH value of the sub-electrolytic cell by more than ±0.5, trigger the modulation process; if the deviation ≤ ±0.5, skip the modulation tank and directly transport the seawater to the sub-electrolytic cell.

9. A system for preparing sodium hypochlorite by electrolyzing seawater with power saving, characterized in that, Including: An electrolysis device, including: a main electrolytic cell and more than two sub-electrolytic cells; Positive and negative electrodes are provided in both the main electrolytic cell and each sub-electrolytic cell, and the electrolysis voltage and current parameters of the main electrolytic cell and each sub-electrolytic cell can be adjusted dynamically separately, and the main electrolytic cell is connected to each sub-electrolytic cell through different pumping pipelines; A monitoring device, including a seawater parameter detection module, a shunt 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 sub-electrolytic cell in real time; The shunt control module is used to pump the seawater in the main electrolytic cell into the sub-electrolytic cell with the best corresponding electrolysis parameters for continuous electrolysis according to the detection results of the seawater parameter detection module, and at the same time supplement new seawater into the main electrolytic cell to keep the composition and concentration of the seawater in the main electrolytic cell dynamically within the preset range; The parameter fine-tuning module fine-tunes the electrolysis voltage and current parameters in the main electrolytic cell and each electrolytic cell according to the detection results of the seawater parameter detection module on the seawater parameters in the main electrolytic cell and each sub-electrolytic cell to adapt to the seawater parameters in each cell to achieve the best electrolysis efficiency.

10. The system for preparing sodium hypochlorite by electrolyzing seawater with power saving according to claim 9, wherein, The shunt control module controls the shunt of seawater between the main electrolytic cell and the sub-electrolytic cells according to the preset seawater composition - electrolytic cell matching rule.

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