A method and system for safe production control of caustic soda

Abstract

The present application provides a safe production control method and system for caustic soda, which relates to the technical field of control and regulation of the caustic soda production process, wherein the control method includes steps such as electrolysis, dechlorination and evaporation; the control system includes a brine preparation module, an electrolysis module, a dechlorination module, an evaporation module, etc. The entire production process of the present application realizes adaptive control and adaptive regulation of the mixture delivery speed, so that the entire production process is in the best state, significantly improving the safety and efficiency of the caustic soda production process.

Description

Technical Field

[0001] The present application relates to the technical field of control and regulation of caustic soda production process, and in particular to a method and system for safe production control of caustic soda. Background Art

[0002] The production of caustic soda (sodium hydroxide, NaOH) occupies a pivotal position. It is not only the core component of basic chemical raw materials, but also widely used in papermaking, textiles, detergents, water treatment and petrochemical industries, playing a vital role in promoting the prosperity and development of these industries. However, the production process of caustic soda is a critical and complex technical challenge. The safety of its operation and the level of production efficiency are not only directly related to the economic benefits and market competitiveness of the enterprise, but also have a profound impact on environmental protection and the fulfillment of social responsibilities.

[0003] The production process of caustic soda includes: electrolysis, dechlorination and evaporation steps. During the production process of caustic soda, the delivery speed of the electrolyte affects the efficiency and effect of its electrolysis. If it is too fast, it may cause uneven distribution of the electrolyte in the electrolytic cell, affect the current density distribution, and reduce the electrolysis efficiency; if it is too slow, it may extend the electrolysis cycle and increase energy consumption; during the dechlorination process, the delivery speed of the dilute brine is directly related to the contact time and reaction efficiency of free chlorine and the dechlorination agent (such as sulfur dioxide, sodium sulfite, etc.); during the evaporation process, the delivery speed of the dilute alkali solution will affect the evaporation liquid level and evaporation concentration. If it is too fast, it may cause large fluctuations in the evaporator liquid level and affect the stability of the evaporation temperature; if it is too slow, it may reduce the evaporation rate and increase energy consumption.

[0004] Therefore, developing and applying advanced adaptive control and regulation methods to achieve precise control of the conveying speeds of various mixtures in the caustic soda production process is of great significance for improving the safety, efficiency and product quality of caustic soda production. Summary of the invention

[0005] In order to improve the adaptive control and regulation of the caustic soda production process, the present application provides a caustic soda safe production control method and system.

[0006] In the first aspect, the present application provides a method for safe production control of caustic soda, which adopts the following technical solution:

[0007] A method for controlling the safe production of caustic soda comprises the following steps:

[0008] Electrolysis: including acid addition, first collection, connection, first control and first electrolysis steps;

[0009] Acid addition: mixing brine and high-purity hydrochloric acid to obtain a first mixture, and transporting the first mixture to the electrolytic cell;

[0010] First acquisition: real-time acquisition of current data in the electrolytic cell, processing the current data, and adjusting the output current data of the rectifier according to the processed current data to obtain first data;

[0011] Establishing a relationship: establishing a corresponding relationship between the first data and the first mixture delivery speed, and establishing a level of the output current data of the rectifier;

[0012] First control: according to the current output current data of the rectifier, by controlling the opening of the electrolytic cell input valve, the speed of conveying the first mixture to the electrolytic cell is adjusted;

[0013] First electrolysis: electrolyzing the first mixture to obtain light salt water and light alkali solution;

[0014] Dechlorination: includes the second control and chloride ion removal steps;

[0015] Second control: adjusting the output speed of the dilute brine by controlling the opening of the first output valve of the electrolytic cell;

[0016] Removing chloride ions: sending the dilute brine into a vacuum dechlorination tower to remove chloride ions in the dilute brine;

[0017] Evaporation: including the third control, heating and evaporation steps of the mixed liquid;

[0018] The third control: adjusting the output speed of the diluted alkali solution by controlling the opening of the second output valve of the electrolytic cell;

[0019] Heating: heating the weak alkali solution to a boiling state to obtain a second mixture;

[0020] Evaporating the mixed solution: mixing the second mixture with alkali to obtain a third mixture, and performing evaporation treatment on the third mixture to obtain caustic soda.

[0021] By adopting the above technical scheme, the present application mixes brine with high-purity hydrochloric acid, adjusts the pH value of the electrolyte, and makes it in the best conditions suitable for electrolysis, which helps to reduce side reactions in the electrolysis process and improve the electrolysis efficiency. The current data in the electrolytic cell is collected in real time, and the output current of the rectifier is accurately adjusted according to these data to ensure the stable electrolysis process. By controlling the delivery speed of the first mixture, the electrolysis effect can be further optimized, so that the components of the electrolysis products (salt water and alkaline solution) are more stable, laying a good foundation for subsequent treatment. Adjusting the output speed of the salt water helps to balance the reaction rate in the electrolytic cell and avoid excessive accumulation of salt water in the electrolytic cell, which affects the electrolysis efficiency. By controlling the speed at which the salt water is input to the vacuum dechlorination tower, the contact time and reaction efficiency of free chlorine and dechlorinating agent (such as sulfur dioxide, sodium sulfite, etc.) can be controlled to separate chloride ions. The heated second mixture is mixed with alkali to form a third mixture, and evaporated. During the evaporation process, the evaporation liquid level and evaporation concentration are controlled by controlling the delivery speed of the alkaline solution, thereby improving the automation level and product quality of the evaporation process.

[0022] Optionally, the first control step includes: second acquisition, first judgment, fourth control and fifth control steps;

[0023] Second collection: collect the current output current data of the rectifier;

[0024] First judgment: judging whether the output current data is lower than a preset threshold value, if so, executing the fourth control step; if not, executing the fifth control step;

[0025] The fourth control includes the first adjustment, the second adjustment and the second judgment steps;

[0026] First adjustment: increasing the output current data with a preset iteration step length, recorded as the second data;

[0027] Second adjustment: increasing the conveying speed of the first mixture according to the second data;

[0028] Second judgment: judging whether the second data is greater than the preset maximum target current data, if so, executing the second acquisition step; if not, executing the first adjustment step;

[0029] The fifth control includes the third adjustment, the fourth adjustment and the third judgment step;

[0030] Third adjustment: reducing the output current data with a preset iteration step length, recorded as the third data;

[0031] Fourth adjustment: reducing the conveying speed of the first mixture according to the third data;

[0032] Third judgment: judge whether the third data is less than the preset minimum target current data, if so, execute the second acquisition step; if not, execute the third adjustment step.

[0033] By adopting the above technical scheme, the present application collects the current data in the electrolytic cell in real time, pre-processes the current data, adjusts the output current of the rectifier according to the processed current data, and records the output current of the rectifier as the first data; establishes the corresponding relationship between the first data and the conveying speed of the first mixture, and can automatically query the corresponding conveying speed of the first mixture according to the output current data of the rectifier in the control step, without manually judging and adjusting the conveying speed of the first mixture. Based on the current data in the electrolytic cell, the output current data of the rectifier is adjusted, and when the current output current data of the rectifier is lower than the preset threshold, the output current of the rectifier is increased by a preset step size, and the conveying speed of the first mixture is adjusted according to the change of the output current; when the output current of the rectifier is not lower than the preset threshold, the output current of the rectifier is reduced by a preset step size, and the conveying speed of the first mixture is adjusted according to the change of the output current of the rectifier, and the output current of the rectifier and the conveying speed of the first mixture are adaptively adjusted to achieve adaptive control of the current in the electrolysis process.

[0034] Optionally, after executing the first judging step and before executing the fourth controlling step, the method further includes:

[0035] First acquisition level: obtain the level to which the current output current data of the rectifier belongs, recorded as the first level, and obtain the previous level of the first level, recorded as the second level;

[0036] First acquisition threshold difference: acquiring the threshold difference of the second level, recorded as the first threshold difference, acquiring an integer multiple of the first threshold difference, recorded as the fourth data, and using the fourth data as the new preset maximum target current data;

[0037] The calculation model of the first threshold difference is:

[0038] A=BC;

[0039] Among them, A is the first threshold difference; B is the upper limit of the second level; C is the lower limit of the second level.

[0040] By adopting the above technical solution, the present application obtains the current level, obtains the threshold difference of the previous level according to the current level, and sets the new preset maximum target current data accordingly. It can adaptively adjust the output current data of the rectifier according to the current output current data of the rectifier and the correspondence between the first data and the first mixture delivery speed in the connection step. The present application calculates the threshold difference and sets the preset maximum target current data according to the threshold difference, which can improve the control accuracy of the output current of the rectifier while ensuring the stable operation of the electrolysis process. The present application can better adapt to the changes in the output current data of the rectifier by dynamically adjusting the preset maximum target current data, which helps to improve the stability of the entire system.

[0041] Optionally, after executing the fourth control step and before executing the fifth control step, the method further includes:

[0042] Second acquisition level: obtain the level to which the current output current data of the rectifier belongs, recorded as the third level, and obtain the next level of the third level, recorded as the fourth level;

[0043] Second acquisition threshold difference: acquiring the threshold difference of the fourth level, recorded as the second threshold difference, acquiring the integer multiple of the second threshold difference, recorded as the fifth data, and using the fifth data as the new preset minimum target current data;

[0044] The calculation model of the second threshold difference is:

[0045] D = EF;

[0046] Among them, D is the second threshold difference; E is the upper limit of the fourth level; F is the lower limit of the fourth level.

[0047] By adopting the above technical solution, the present application obtains the threshold difference of the next level and sets the new preset minimum target current data accordingly. It can adaptively adjust the output current data of the rectifier according to the current output current data of the rectifier and the correspondence between the first data and the first mixture delivery speed in the connection step. The present application calculates the threshold difference and sets the preset minimum target current data according to the threshold difference, which can improve the control accuracy of the output current data of the rectifier while ensuring the stable operation of the electrolysis process. The present application can better adapt to the changes in the output current data of the rectifier by dynamically adjusting the preset minimum target current data, which helps to improve the stability of the entire system.

[0048] Optionally, after performing the third adjustment step and before performing the fourth adjustment step, the method further includes:

[0049] Setting a safety threshold: Preset a safety threshold, calculate the sum of the third data and the safety threshold, and use the sum of the third data and the safety threshold as new third data.

[0050] By adopting the above technical solution, the present application presets a safety threshold and takes the preset safety threshold into consideration in subsequent calculations, which can ensure that the safety range will not be exceeded during the process of reducing the first mixture delivery speed, thereby enhancing the safety of the system.

[0051] Optionally, after executing the fourth adjusting step and before executing the third judging step, the method further includes:

[0052] Calculation: Subtract the safety threshold from the third data to obtain sixth data, and use the sixth data as new third data.

[0053] By adopting the above technical solution, the present application realizes the update of the third data by subtracting the safety threshold from the third data, ensuring that the latest third data with the safety margin removed is used in the subsequent third judgment step, and comparing it with the preset minimum target current data. The system can quickly identify the gap between the two and make corresponding control decisions accordingly. Through real-time comparison and adjustment, the present application can ensure that the third data can be as close to the preset minimum target current data as possible and reduce the output current data of the rectifier as quickly as possible under the premise of ensuring safe production.

[0054] Optionally, before performing the electrolysis step, the method further comprises:

[0055] First preparation: preparing brine, filtering the brine to obtain first brine;

[0056] Second preparation: transport the heated first brine to a resin tower to remove calcium ions and magnesium ions to obtain second brine, and use the second brine as new brine.

[0057] By adopting the above technical solution, the present application filters the salt water to remove impurities therein, such as suspended matter, particulate matter, etc., thereby obtaining a pure first salt water, which has less corrosive effect on the electrolysis equipment and can extend the service life of the equipment. In the resin tower, the calcium ions and magnesium ions of the first salt water are removed, and these two ions will have adverse effects in the electrolysis process, such as forming precipitation, reducing the electrolysis efficiency, etc., to obtain a second salt water with calcium ions and magnesium ions removed, the second salt water is purer and more suitable for the subsequent electrolysis process, and the products (such as chlorine, hydrogen, caustic soda, etc.) produced after the electrolysis of the pure second salt water are of higher quality.

[0058] Optionally, after performing the first electrolysis step and before performing the dechlorination step, the method further comprises:

[0059] Monitoring: monitoring the pH value of the first mixture in the electrolytic cell in real time to obtain a first pH value;

[0060] Fourth judgment: judging whether the first pH value exceeds a preset threshold value, if so, executing the fifth adjustment step; if not, executing the monitoring step;

[0061] Fifth adjustment: adding hydrochloric acid to the first mixture and performing a monitoring step.

[0062] By adopting the above technical solution, the present application monitors the first pH value in real time and determines whether the first pH value exceeds the preset threshold value. If the first pH value exceeds the preset threshold value, it means that the acidity of the first mixture is insufficient and needs to be adjusted. Therefore, hydrochloric acid needs to be added to the first mixture to increase the acidity of the first mixture so that it returns to the preset range. If the first pH value does not exceed the preset threshold value, it means that the acidity of the first mixture is moderate and does not need to be adjusted. Therefore, the monitoring step is continued and continuous monitoring is performed. By real-time monitoring and adjusting the pH value of the first mixture, the present application can ensure the stable operation of the electrolysis process and avoid the decrease in electrolysis efficiency or equipment damage caused by insufficient acidity of the first mixture. The stable acidic environment of the first mixture provides good conditions for the subsequent dechlorination step, which helps to improve the dechlorination efficiency and product quality.

[0063] Optionally, after executing the fourth determining step and before executing the fifth adjusting step, the method further includes:

[0064] Data collection: collecting historical pH value deviations and historical pH value deviation change rates, and processing the historical pH value deviations and historical pH value deviation change rates respectively, and recording them as the seventh data and the eighth data respectively;

[0065] Building a database: Building a fuzzy rule database, wherein the fuzzy rule database stores: the seventh data, the eighth data, and the adjustment strategy of the PID controller parameters;

[0066] Data processing: processing the first pH value to obtain a second pH value;

[0067] Data comparison: comparing the second pH value with the reference pH value to obtain the pH value deviation and the pH value deviation change rate;

[0068] Data conversion: convert pH value deviation and pH value deviation change rate into fuzzy language variables;

[0069] Fuzzy reasoning: According to the fuzzy language variables and adjustment strategies, fuzzy reasoning is performed on the PID controller parameters to obtain the adjustment amount of the PID controller parameters;

[0070] Parameter adjustment: adjust the PID controller parameters according to the adjustment amount, and output the amount of hydrochloric acid added.

[0071] By adopting the above technical scheme, the present application adopts fuzzy reasoning and dynamically adjusts the parameters of the PID controller, which can more accurately control the pH value of the first mixture and improve the stability and efficiency of the electrolysis process. The present application can be dynamically adjusted according to the real-time changes and historical trends of the pH value of the first mixture, and has strong adaptability and robustness. The present application can automatically carry out data collection, processing and reasoning processes, reduce the need for human intervention, and improve the automation level of the production process. The present application can optimize the use efficiency of hydrochloric acid, reduce resource waste and reduce costs by accurately controlling the amount of hydrochloric acid added.

[0072] In the second aspect, the present application provides a safe production control system for caustic soda, which adopts the following technical solution:

[0073] A safe production control system for caustic soda, comprising:

[0074] A brine preparation module, used for preparing brine;

[0075] The electrolysis module is fixedly connected to the brine preparation module, and includes: an acid adding unit, a collection unit, a data processing unit, a connection unit, a first control and regulation unit, and an electrolysis unit;

[0076] an acid adding unit, used for adding high-purity hydrochloric acid to the brine to obtain a first mixture, and conveying the first mixture to the electrolytic cell;

[0077] A collection unit, used for collecting current data in the electrolytic cell in real time;

[0078] A data processing unit, used to process the current data collected by the collection unit, and adjust the output current data of the rectifier according to the processed current data, which is recorded as the first data;

[0079] A connection unit, used to establish a corresponding relationship between the first data and the first mixture delivery speed, and to establish a level of the output current data of the rectifier;

[0080] A first control and adjustment unit, used to control the opening of the electrolytic cell input valve and adjust the transmission speed of the first mixture according to the output current data of the rectifier;

[0081] Electrolysis unit: used for electrolyzing the first mixture to obtain light salt water and light alkali solution;

[0082] Dechlorination module: including the second control and regulation unit and the chloride ion removal unit;

[0083] A second control and regulation unit, used to control the opening of the first output valve of the electrolytic cell and regulate the output speed of the dilute brine;

[0084] A chloride ion removal unit is used to send the dilute brine into a vacuum dechlorination tower to remove chloride ions in the dilute brine;

[0085] Evaporation module: including a third control unit, a heating unit and an evaporation mixed liquid unit;

[0086] The third control unit is used to control the opening of the second output valve of the electrolytic cell and adjust the output speed of the diluted alkali solution;

[0087] A heating unit is used to heat the weak alkali solution to a boiling state to obtain a second mixture;

[0088] Evaporation mixed liquid unit: used for mixing the second mixture with alkali to obtain a third mixture, and evaporating the third mixture to obtain caustic soda.

[0089] By adopting the above technical scheme, the acquisition unit, data processing unit, control and regulation unit in the electrolysis module ensure the stability of the electrolysis process, thereby ensuring that the final caustic soda solution has stable quality. Through the establishment of the linking unit, real-time monitoring and optimization of key parameters in the electrolysis process (such as the first mixture delivery speed and the output current data of the rectifier) ​​are realized, which helps to reduce resource waste and improve resource utilization efficiency. The setting of the dechlorination module effectively removes chloride ions in the light brine in the electrolytic cell, reduces the emission of harmful substances, and is more environmentally friendly. The third control unit in the evaporation module controls the opening of the second output valve of the electrolytic cell, controls the output speed of the light alkali solution, and realizes the control of the evaporation concentration and evaporation liquid level during the evaporation process. In the entire process flow, from data acquisition, processing to feedback regulation, automatic control is realized, manual intervention is reduced, and the safety and reliability of production are improved. When the output current data of the rectifier deviates from the range of safe production, the first control and regulation unit of the system can adaptively control and adjust the first mixture delivery speed according to the current output current data of the rectifier.

[0090] In summary, the present application includes at least one of the following beneficial technical effects:

[0091] 1. The present application mixes brine with high-purity hydrochloric acid, adjusts the pH value of the electrolyte, and makes it in the best conditions suitable for electrolysis, which helps to reduce side reactions in the electrolysis process and improve the electrolysis efficiency. The current data in the electrolytic cell is collected in real time, and the output current of the rectifier is accurately adjusted according to these data to ensure the stable electrolysis process. By controlling the delivery speed of the first mixture, the electrolysis effect can be further optimized, so that the components of the electrolysis products (salt water and alkaline solution) are more stable, laying a good foundation for subsequent treatment. Adjusting the output speed of the salt water helps to balance the reaction rate in the electrolytic cell and avoid excessive accumulation of salt water in the electrolytic cell, which affects the electrolysis efficiency. By controlling the speed of the salt water input to the vacuum dechlorination tower, the contact time and reaction efficiency of free chlorine and the dechlorination agent (such as sulfur dioxide, sodium sulfite, etc.) can be controlled to separate the chloride ions. The heated second mixture is mixed with the alkali to form a third mixture, and then evaporated. During the evaporation process, by controlling the delivery speed of the alkaline solution, the evaporation level and evaporation concentration can be controlled, and the automation level and product quality of the evaporation process can be improved.

[0092] 2. The present application monitors the first pH value in real time, and determines whether the first pH value exceeds a preset threshold value. If the first pH value exceeds the preset threshold value, it indicates that the acidity of the first mixture is insufficient and needs to be adjusted. Therefore, hydrochloric acid needs to be added to the first mixture to increase the acidity of the first mixture so that it returns to the preset range. If the first pH value does not exceed the preset threshold value, it indicates that the acidity of the first mixture is moderate and does not need to be adjusted. Therefore, the monitoring step is continued and continuous monitoring is performed. The present application can ensure the stable operation of the electrolysis process by real-time monitoring and adjusting the pH value of the first mixture, avoiding a decrease in electrolysis efficiency or equipment damage due to insufficient acidity of the first mixture. The stable acidic environment of the first mixture provides good conditions for the subsequent dechlorination step, which helps to improve dechlorination efficiency and product quality.

[0093] 3. The present application obtains the current level, obtains the threshold difference of the previous level according to the current level, and sets the new preset maximum target current data accordingly, and can adaptively adjust the output current data of the rectifier according to the current output current data of the rectifier, combined with the corresponding relationship between the first data and the first mixture delivery speed in the linking step. The present application calculates the threshold difference and sets the preset maximum target current data according to the threshold difference, which can improve the control accuracy of the output current of the rectifier while ensuring the stable operation of the electrolysis process. The present application dynamically adjusts the preset maximum target current data to better adapt to the changes in the output current data of the rectifier, which helps to improve the stability of the entire system. The present application obtains the threshold difference of the next level of the current level, and sets the new preset minimum target current data accordingly, and can adaptively adjust the output current data of the rectifier according to the current output current data of the rectifier, combined with the corresponding relationship between the first data and the first mixture delivery speed in the linking step. The present application calculates the threshold difference and sets the preset minimum target current data according to the threshold difference, which can improve the control accuracy of the output current data of the rectifier while ensuring the stable operation of the caustic soda production process. The present application can better adapt to changes in the rectifier output current data by dynamically adjusting the preset minimum target current data, thereby helping to improve the stability of the entire system.

[0094] 4. The acquisition unit, data processing unit, control and regulation unit in the electrolysis module of the present application ensure the stability of the electrolysis process, thereby ensuring that the final caustic soda solution has stable quality. Through the establishment of the joint unit, real-time monitoring and optimization of key parameters (such as the first mixture delivery speed and the output current data of the rectifier) ​​in the electrolysis process are realized, which helps to reduce resource waste and improve resource utilization efficiency. The setting of the dechlorination module effectively removes the chloride ions in the light brine in the electrolytic cell, reduces the emission of harmful substances, and is more environmentally friendly. The third control unit in the evaporation module controls the opening of the second output valve of the electrolytic cell, controls the output speed of the light alkali solution, and realizes the control of the evaporation concentration and evaporation level during the evaporation process. In the entire process flow, from data acquisition, processing to feedback regulation, automatic control is realized, manual intervention is reduced, and the safety and reliability of production are improved. When the output current data of the rectifier deviates from the scope of safe production, the first control and regulation unit of the present system can adaptively control and adjust the first mixture delivery speed according to the current output current data of the rectifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0095] Figure 1 is a flow chart of Example 1 of the present application;

[0096] Figure 2 is a flow chart of the electrolysis step S2 of Example 1 of the present application;

[0097] Figure 3 is a flowchart of control step S24 of Example 1 of the present application;

[0098] Figure 4 This is a flowchart of Example 1 of the present application with step S25 added. DETAILED DESCRIPTION

[0099] The following combination Figures 1 to 4 This application is described in further detail.

[0100] Example 1: This example discloses a safe production control method for caustic soda, referring to Figure 1 The control method comprises the following steps: preparation step S1, electrolysis step S2, dechlorination step S3, evaporation step S4. In this embodiment, salt water for electrolysis is first prepared, then the salt water is electrolyzed, then the chloride ions generated in the electrolysis process are dechlorinated, and then the electrolyzed weak alkali solution is evaporated to obtain caustic soda. The specific process of this method is as follows:

[0101] The preparation step S1 includes a first preparation step S11 and a second preparation step S12.

[0102] S11 First Preparation: In this step, a high-purity water source is selected as the basis to ensure that there are not too many impurities and harmful substances in the water, and an appropriate amount of salt (which can be table salt or industrial-grade sodium chloride) is prepared as the source of salt. A certain amount of salt is slowly added to the prepared water source, and stirred at the same time to ensure that the salt can be evenly and quickly dissolved in the water to obtain brine. In this process, the stirring speed and the rate of adding salt need to be controlled to prevent the local concentration from being too high and causing salt to agglomerate.

[0103] The salt water is filtered through a filter equipped with a multi-layer filter screen to remove large particle impurities, suspended matter and some insoluble substances in the salt water, thereby improving the clarity and purity of the salt water. The filtered salt water is the first salt water.

[0104] S12 Second preparation: The first salt water is heated, and the heating treatment includes steam heating, electric heating or heat exchanger. According to the temperature tolerance range of the resin tower used in this step, in this embodiment, the first salt water is heated to (55±5)°C and then transported to the resin tower to cause ion exchange reaction.

[0105] The resin tower is filled with highly selective cation exchange resin, which can effectively adsorb and remove hard water ions such as calcium and magnesium in the water. Before sending the heated first brine into the resin tower, it is necessary to check the operating status of the resin tower, including the saturation, regeneration and sealing of the resin, to ensure the treatment effect on calcium ions and magnesium ions. If the operating status of the resin tower does not meet the requirements, the resin tower needs to be replaced and its operating status rechecked.

[0106] The heated first brine is transported to the resin tower through a pipeline for ion exchange treatment. During this process, the hydrogen ions (H+) on the resin are exchanged with the calcium ions (Ca²+), magnesium ions (Mg²+), etc. in the brine.

[0107] like Figure 2 As shown, the electrolysis step S2 includes an acid adding step S21, a first collection step S22, a connection step S23, a first control step S24 and an adding step S25.

[0108] S21 Acid addition: High-purity hydrochloric acid (in this embodiment, the high-purity hydrochloric acid is 19% hydrochloric acid) is injected into the second brine prepared in the second preparation step S12 at a flow rate of 2 liters per minute. During the injection of high-purity hydrochloric acid, stirring is performed continuously to allow the two to react fully and evenly during the mixing process to reduce the occurrence of local over-concentration or over-low concentration. During the mixing process, the temperature is controlled (the temperature of the mixed solution is controlled at about 80°C) to maintain the mixed solution within the optimal reaction temperature range, promote the complete reaction of salt and acid, and thus generate a first mixture suitable for electrolysis. The first mixture is then pumped or self-flowed into the electrolytic cell and electrolyzed in the electrolytic cell.

[0109] S22 First acquisition: In order to monitor the efficiency and stability of the electrolysis process in real time, this embodiment acquires the current data in the electrolytic cell in real time. These current data are captured by high-precision current sensors, and the current data are transmitted to the data processing unit. In the data processing unit, filtering operation is first performed to remove noise and interference signals in the current data; then standardization processing is performed to ensure that the current data collected at different times or conditions have a certain comparability; finally, feature extraction is performed to extract key information useful for electrolysis process analysis, such as current peak value, average value, fluctuation range, etc., and according to the processed current data, the output current data of the rectifier is adjusted, and the adjusted output current data of the rectifier is recorded as the first data.

[0110] S23 Establishing a connection: Establishing a dynamic correspondence between the first data and the first mixture delivery speed, specifically: using statistical analysis, machine learning or expert system methods to analyze the first data and identify key indicators related to electrolysis efficiency, reaction rate, etc. For example, changes in the output current intensity of the rectifier are directly related to the rate of the electrolysis reaction; and fluctuations in the output current data of the rectifier indicate unevenness or potential failures in the electrolytic cell.

[0111] Based on the result of data analysis, a dynamic mathematical model or a lookup table is established to associate the first data with the first mixture delivery speed, so as to facilitate the search for the corresponding relationship between the two in subsequent steps.

[0112] During the electrolysis process, the first data is continuously monitored, and the delivery speed of the first mixture is adjusted in real time according to the established corresponding relationship. For example, if the current data in the electrolytic cell decreases, it indicates that the electrolysis reaction rate decreases, and the system automatically increases the output current data of the rectifier, and then searches for the target first mixture delivery speed according to the increased output current data of the rectifier, adjusts the valve opening according to the target first mixture delivery speed, and then adjusts the current first mixture delivery speed, thereby increasing the delivery speed of the first mixture to provide more reactants; increase the output current of the rectifier to increase the electrolysis speed. On the contrary, if the output current data of the rectifier increases and exceeds the preset maximum target current data, it indicates that the electrolytic cell is close to overload, and the system will reduce the delivery speed of the first mixture to avoid potential safety problems. For example: During the electrolysis process, it was found that the electrolysis efficiency was highest when the current intensity was stable at 10.5KA. Through data analysis and modeling, at this current intensity, the optimal delivery speed of the first mixture is 60 liters per hour. Therefore, during the electrolysis process, when the system detects that the current intensity deviates from 10.5KA (whether it is rising or falling), it will automatically adjust the delivery rate of the first mixture to stabilize the current intensity around 10.5KA, thereby maintaining the optimal electrolysis efficiency.

[0113] This embodiment also collects the effect data after adjustment, and optimizes and adjusts the established corresponding relationship through the feedback mechanism. In this way, as time goes by and experience accumulates, the system can adjust the delivery speed of the first mixture more and more accurately to achieve the best electrolysis efficiency and stability.

[0114] As shown in Table 1, this embodiment also sets the levels of the output current data of the rectifier, and these levels are set with reference to the design parameters, working conditions and process requirements of the rectifier.

[0115] Table 1 Level table of rectifier output current data

[0116]

[0117] like Figure 3 As shown, the first control step S24 is: according to the current output current data of the rectifier, by controlling the opening of the electrolytic cell input valve, the speed of conveying the first mixture to the electrolytic cell is adjusted. The first control step S24 includes a second acquisition step S241, a first judgment step S242, a fourth control step S243 and a fifth control step S244.

[0118] S241 Second collection: collect the current output current data of the rectifier, and store the collected output current data each time in a predetermined format and time interval as a basis for subsequent analysis and control.

[0119] S242 First judgment: judge whether the output current data is lower than the preset threshold value, if so, execute the fourth control step S243; if not, execute the fifth control step S244.

[0120] The fourth control step S243 includes a first level acquisition step S2431, a first threshold difference acquisition step S2432, a first adjustment step S2433, a second adjustment step S2434 and a second judgment step S2435.

[0121] S2431 First acquisition level: Real-time monitoring of the output current data of the rectifier, according to the level of the output current data of the rectifier set in Table 1 of the connection step S23, the real-time collected output current data is compared with the predefined level range in Table 1, and the level to which the current output current data of the rectifier belongs is determined, which is recorded as the first level. For example, if the current output current data of the rectifier is 12KA, then the level to which it belongs is level 6. According to the predefined level order, the previous level of the first level (i.e., level 5 in Table 1) is obtained and recorded as the second level. If the current level is already the highest level, the current level is directly used as the second level.

[0122] S2432 first obtain threshold difference: obtain the threshold difference of the second level, record it as the first threshold difference, obtain the integer multiple of the first threshold difference, record it as the fourth data, and use the fourth data as the new preset maximum target current data.

[0123] The calculation model of the first threshold difference is:

[0124] A=BC;

[0125] Among them, A is the first threshold difference; B is the upper limit of the second level; C is the lower limit of the second level. As shown in Table 1, the value of the first threshold difference is 0.5KA, and according to the value range of current intensity shown in Table 1, the integer multiple of the first threshold difference does not exceed 28 times and is not less than 19 times, that is, in the first threshold difference acquisition step S2432, the preset maximum target current data should be in the range of 9.5KA to 14KA. In this embodiment, the preset maximum target current data is 14KA.

[0126] S2433 first adjustment: take the current range (0.5KA) corresponding to the second level as the iteration step, increase the output current data, and record the adjusted output current as the second data.

[0127] S2434 second adjustment: according to the second data, combined with the dynamic correspondence between the first data and the first mixture delivery speed established in the association step S23, according to the second data changed in the first adjustment step S2433, the target first mixture delivery speed is obtained, and according to the target first mixture delivery speed, the valve opening is increased to increase the current first mixture delivery speed. Through multiple iterations and adjustments, the matching relationship between the first mixture delivery speed and the output current data of the rectifier is gradually optimized, so that the system can achieve a stable and efficient working state.

[0128] S2435 Second judgment: judge whether the second data in the first adjustment step S2433 is greater than the preset maximum target current data (14KA), if so, execute the second acquisition step S241; if not, execute the first adjustment step S2433.

[0129] S244 Fifth control: includes a second level acquisition step S2441, a second threshold difference acquisition step S2442, a third adjustment step S2443, a safety threshold setting step S2444, a fourth adjustment step S2445, a calculation step S2446 and a third judgment step S2447.

[0130] S2441 Second acquisition level: obtain the current output current data of the rectifier, and the corresponding level in Table 1 is recorded as the third level. For example, if the current output current data of the rectifier is 12KA, then the level it belongs to is level 6. According to the predefined level sequence, obtain the next level of the third level (that is, level 7 in Table 1), which is recorded as the fourth level.

[0131] S2442 second acquisition threshold difference: obtain the threshold difference of the fourth level, record it as the second threshold difference, obtain the integer multiple of the second threshold difference, record it as the fifth data, and use the fifth data as the new preset minimum target current data.

[0132] The calculation model of the second threshold difference is:

[0133] D = EF;

[0134] Wherein, D is the second threshold difference; E is the upper limit of the fourth level; and F is the lower limit of the fourth level. As shown in Table 1, the value of the second threshold difference is 0.5KA, and according to the value range of the current intensity shown in Table 1, the integer multiple of the second threshold difference does not exceed 28 times and is not less than 19 times, that is, in the second threshold difference acquisition step S2442, the preset minimum target current data should be in the range of 9.5KA to 14KA. In this embodiment, the preset minimum target current data is 9.5KA.

[0135] S2443 third adjustment: using the current range corresponding to the fourth level (0.5KA) as the iteration step, reducing the output current data, recorded as the third data.

[0136] S2444 sets a safety threshold: preset a safety threshold, calculate the sum of the third data and the safety threshold, take the sum of the third data and the safety threshold as the new third data, and take the safety threshold as 0.025KA.

[0137] S2445 Fourth adjustment: gradually reduce the first mixture delivery speed according to the third data obtained in step S2444 of setting the safety threshold. In this step, according to the updated third data, in combination with the dynamic correspondence between the first data and the first mixture delivery speed established in step S23, the target first mixture delivery speed corresponding to the updated third data is obtained, and the current first mixture delivery speed is gradually reduced according to the target first mixture delivery speed.

[0138] S2446 calculation: subtract the set safety threshold from the third data finally obtained in the third adjustment step S2443 to obtain sixth data.

[0139] S2447 Third judgment: judge whether the sixth data is less than the preset minimum target current data (9.5KA). If the sixth data is less than the preset minimum target current data, it means that the output current has been reduced to a level close to or below the safety level, and the second acquisition step S241 is executed at this time. If the sixth data is not less than the preset minimum target current data, it means that there is room for further adjustment, and the third adjustment step S2443 is continued to be executed to continue to reduce the output current data with the preset iteration step, thereby reducing the delivery speed of the first mixture.

[0140] After electrolyzing the first mixture, a desalinated brine is obtained in the anode tank of the electrolytic cell, and a desalinated alkali solution is obtained in the cathode tank of the electrolytic cell.

[0141] like Figure 4 As shown, the adding step S25 includes a monitoring step S251, a fourth judging step S252, a hydrochloric acid determining step S253 and a fifth adjusting step S254.

[0142] S251 Monitoring: Real-time monitoring of the pH value of the first mixture in the electrolytic cell to obtain a first pH value.

[0143] S252 Fourth judgment: judge whether the first pH value exceeds the preset threshold value, if so, execute the step of determining the amount of hydrochloric acid S253; if not, execute the monitoring step S251.

[0144] The step S253 of determining the amount of hydrochloric acid includes a data collection step S2531, a database building step S2532, a data processing step S2533, a data comparison step S2534, a data conversion step S2535, a fuzzy reasoning step S2536 and a parameter adjustment step S2537.

[0145] The pH value data of the first mixture is collected by a high-precision pH sensor installed on the production line and stored in a database.

[0146] The historical pH value data is extracted from the database regularly to calculate the historical pH value deviation (i.e. the absolute value of the difference between the actual historical pH value and the set reference pH value) and the historical pH value deviation change rate (i.e. the change in pH value deviation in adjacent time periods). The historical pH value deviation refers to the difference between the historical pH value actually measured in a certain period of time in the past and the preset reference pH value. The historical pH value deviation change rate reflects the speed of the historical pH value deviation changing over time (i.e. the change in pH value deviation in adjacent time periods).

[0147] S2531 Data collection: In the database, extract the historical pH value deviation and the historical pH value deviation change rate, and process the historical pH value deviation and the historical pH value deviation change rate respectively, including denoising, smoothing and outlier removal, to ensure the accuracy and reliability of the data. The processed historical pH value deviation is recorded as the seventh data, and the processed historical pH value deviation change rate is recorded as the eighth data.

[0148] S2532 Library building: In order to realize intelligent adjustment of PID controller parameters, a fuzzy rule library containing rich rules is constructed based on long-term production experience and experimental data. The fuzzy rule library stores: the seventh data and the eighth data, the adjustment strategy of the PID controller parameters, and the mapping relationship between the three.

[0149] The fuzzy rule base is based on expert experience and experimental data, and takes the seventh data (processed historical pH value deviation) and the eighth data (processed historical pH value deviation change rate) as input variables. The output variable is the adjustment strategy of the PID controller parameters, and the adjustment strategy includes: the adjustment direction and amplitude of the proportional coefficient Kp, the integral time Ti and the differential time Td. These adjustment strategies are expressed in the form of "if-then". For example, when the historical pH value deviation increases and the deviation change rate is fast, it is indicated to increase the proportional coefficient Kp to speed up the response speed, and appropriately reduce the integral time Ti to reduce overshoot.

[0150] S2533 Data processing: Receive the first pH value data from the pH sensor in real time, remove high-frequency noise through a filtering algorithm, and perform necessary calibration to obtain a more accurate and reliable second pH value.

[0151] S2534 Data comparison: directly compare the second pH value with the preset reference pH value to obtain the pH value deviation, and further calculate the change rate of the deviation relative to the previous time point, that is, the pH value deviation change rate.

[0152] S2535 Data conversion: In order to meet the needs of fuzzy control, the continuously changing pH deviation and pH deviation change rate are converted into fuzzy language variables. This process involves defining fuzzy sets (such as "positive large", "negative small", etc.) and membership functions, mapping precise values ​​to these fuzzy sets, thereby achieving a conversion from quantitative to qualitative.

[0153] S2536 Fuzzy reasoning: Based on the fuzzy language variables of the data conversion step S2535 and the adjustment strategy of the PID controller parameters in the fuzzy rule library of the library building step S2532, the decision is made through the fuzzy reasoning mechanism. This process simulates the decision-making process of human experts when facing uncertainty and ambiguity. By matching the rules in the fuzzy rule library, comprehensively considering the current pH value deviation and the pH value deviation change rate, the reasonable adjustment amount of the PID controller parameters is inferred.

[0154] S2537 Parameter adjustment: According to the adjustment amount obtained in the fuzzy reasoning step S2536, the parameters of the PID controller are adjusted accordingly. These adjustments are intended to optimize the control performance so that the system can reach the target pH value faster and more stably. After the adjustment is completed, the PID controller calculates the current amount of hydrochloric acid to be added based on the new PID parameters and outputs it to the acid addition unit to achieve accurate control of the pH value.

[0155] The PID controller calculates the amount of hydrochloric acid to be added according to the new PID parameters, comprising the following steps:

[0156] S25371 sets the target pH value: In this embodiment, the pH value of the first mixture ranges from 1.65 to 2.5.

[0157] S25372 adjusts PID parameters: input current pH value, pH value deviation e (obtained by subtracting the current pH value from the target pH value and taking the absolute value), and pH value deviation change rate ec (obtained by taking the derivative of pH value deviation e).

[0158] Convert the exact values ​​of input pH deviation e and pH deviation change rate ec into fuzzy sets (such as "negative large", "negative small", "zero", "positive small", "positive large", etc.). In the fuzzy rule base, query the adjustment strategy of PID controller parameters, and convert the adjustment strategy into accurate PID parameter adjustment through algorithms (such as maximum membership method, weighted average method, etc.).

[0159] S25373 Obtaining the amount of hydrochloric acid: The calculation model of the PID controller is as follows:

[0160] ;

[0161] Among them, P is the control quantity, that is, the amount of hydrochloric acid that needs to be added, in liters; Kp is the proportional coefficient, Ti is the integral time, and Td is the differential time. The three are the parameter adjustment quantities of the PID controller, which are obtained by adjusting the PID parameters in step S25372.

[0162] Since it is difficult to directly calculate the differential and integral terms in practice, they are approximated in discrete form in this embodiment.

[0163] ;

[0164] ;

[0165] ;

[0166] Wherein, T is the pH value sampling period of the first mixture.

[0167] In other embodiments, the PID controller calculates the current amount of hydrochloric acid to be added based on the new PID parameters, and can be operated based on expert experience, etc., or it can gradually add hydrochloric acid to determine whether the pH value of the monitored first mixture reaches the target pH value. If so, stop adding hydrochloric acid, if not, continue adding hydrochloric acid.

[0168] S254 Fifth adjustment: Obtain the amount of hydrochloric acid calculated in step S25373 into the first mixture, and perform the monitoring step S251.

[0169] The dechlorination step S3 includes a second control step S31 and a chloride ion removal step S32.

[0170] S31 second control: adjusting the output speed of the dilute brine by controlling the opening of the first output valve of the electrolytic cell.

[0171] The first output valve of the electrolytic cell is the channel for the salt water to flow out of the electrolytic cell. Its opening size directly determines the flow rate and flow velocity of the salt water. When the valve opening increases, the output speed of the salt water increases and the flow rate increases; conversely, when the valve opening decreases, the output speed of the salt water slows down and the flow rate decreases.

[0172] The liquid level in the anode tank of the electrolytic cell is monitored by a liquid level sensor. When the measured liquid level value exceeds a preset threshold, the opening of the first output valve is increased to speed up the delivery of the dilute brine. Otherwise, the opening of the first output valve is reduced.

[0173] S32 Removal of chloride ions: using chemical or physical methods to remove chloride ions in the brine output by the first output valve of the electrolytic cell to obtain a second mixture.

[0174] The chemical method is to add a specific dechlorinating agent, such as sulfite or thiosulfate, which can react with chloride ions to generate harmless or easily separable compounds, thereby achieving the removal of chloride ions.

[0175] The physical method is to use adsorption, membrane separation or ion exchange technology to selectively remove chloride ions to purify the solution.

[0176] The liquid level of the brine in the vacuum dechlorination tower is monitored by a liquid level sensor. When the liquid level exceeds a preset threshold, the opening of the first output valve is controlled to be reduced through the second control step S31. Otherwise, the opening of the first output valve is controlled to be increased.

[0177] The evaporation step S4 includes a third control step S41, a heating step S42 and a mixed liquid evaporation step S43.

[0178] S41 third control: adjusting the output speed of the diluted alkali solution by controlling the opening of the second output valve of the electrolytic cell.

[0179] The second output valve of the electrolytic cell is the channel for the weak alkali liquid to flow out of the electrolytic cell. Its opening size directly determines the flow rate and flow velocity of the weak alkali liquid. When the valve opening increases, the output speed of the weak alkali liquid increases and the flow rate increases; conversely, when the valve opening decreases, the output speed of the weak alkali liquid slows down and the flow rate decreases.

[0180] The PID (Proportional-Integral-Differential) control algorithm is used to adjust the valve opening in real time. The PID controller can calculate the adjustment amount of the valve opening according to the error between the set value and the actual value, thereby achieving precise control of the output speed of the diluted alkali liquid.

[0181] By installing a flow meter on the dilute alkali liquid output pipeline, the flow of the dilute alkali liquid is monitored in real time. The feedback signal of the flow meter is compared with the set value, and the valve opening is adjusted through the controller to stabilize the flow of the dilute alkali liquid near the set value.

[0182] S42 heating: heating the weak alkali solution to a boiling state to obtain a second mixture.

[0183] S43 evaporating the mixed solution: mixing the second mixture with a base (such as sodium hydroxide or potassium hydroxide) to generate a third mixture.

[0184] The third mixture is subjected to an evaporation treatment to obtain caustic soda. The evaporation process is carried out in a dedicated evaporator. Through operations such as heating, stirring and condensation, it is ensured that water is efficiently separated in the form of steam while avoiding solute loss and scaling problems.

[0185] This embodiment provides a safe production control method for caustic soda, involving multiple key links such as acid addition, real-time data acquisition, connection and control. First, by accurately controlling the mixing ratio of brine and high-purity hydrochloric acid, a first mixture is generated and sent to the anode tank of the electrolytic cell, and the first mixture is electrolyzed in the electrolytic cell. Subsequently, the first acquisition step captures the current data in the electrolytic cell in real time, pre-processes it, and uses it as a basis to adjust the output current of the rectifier. The connection step cleverly associates the output current data with the first mixture delivery speed, which facilitates the subsequent adjustment of the mixture delivery speed according to the current data. The control link is divided into the second acquisition, the first judgment, the first control, and the second control steps. By continuously monitoring the output current of the rectifier and making intelligent judgments based on the preset threshold, the output current and the mixture delivery speed can be automatically adjusted to maintain the optimal electrolysis state. When the current is low, the electrolysis efficiency is ensured by gradually increasing the current and adjusting the first mixture delivery speed in time; otherwise, the system is kept stable by reducing the current and delivery speed. After the electrolysis is completed, the dechlorination step effectively removes the chloride ions in the solution. The weak caustic soda solution is heated to obtain a second mixture, and then, in an evaporation module, the second mixture is mixed with alkali and evaporated to finally obtain a high-purity caustic soda solution.

[0186] Embodiment 2: This embodiment discloses a safe production control system for caustic soda, comprising:

[0187] The brine preparation module is used for preparing brine.

[0188] The electrolysis module is fixedly connected to the brine preparation module, and includes: an acid adding unit, a collection unit, a data processing unit, a connection unit, a first control and regulation unit, and an electrolysis unit.

[0189] Acid adding unit: This module adds high-purity hydrochloric acid to the brine through a metering pump to obtain a first mixture, and transports the first mixture to the anode tank of the electrolytic cell.

[0190] The acquisition unit is used to acquire the current data in the electrolytic cell in real time.

[0191] The data processing unit is connected to the acquisition unit for processing the current data acquired by the acquisition unit (including cleaning, screening and converting the data), and adjusting the output current data of the rectifier according to the processed current data, which is recorded as the first data.

[0192] The association unit establishes a corresponding relationship between the first data and the first mixture delivery speed, and establishes a level of the output current data of the rectifier.

[0193] The first control and regulation unit is used to control the opening of the electrolytic cell input valve according to the output current data of the rectifier, and intelligently control and regulate the first mixture delivery speed in combination with the information provided by the connection unit.

[0194] Electrolysis unit: used for electrolyzing the first mixture to obtain light brine and light alkali solution.

[0195] Dechlorination module: includes the second control and regulation unit and the chloride ion removal unit.

[0196] The second control and regulation unit is used to control the opening of the first output valve of the electrolytic cell and regulate the output speed of the dilute brine.

[0197] The chloride ion removal unit has an input end fixedly connected to an output end of the electrolysis module, and removes chloride ions from the salt water by chemical or physical methods, such as adding a dechlorinating agent or using adsorption technology.

[0198] Evaporation module: includes a third control unit, a heating unit and an evaporation mixed liquid unit.

[0199] The third control unit is used to control the opening of the second output valve of the electrolytic cell and adjust the output speed of the dilute alkali solution.

[0200] Heating unit: used for heating the weak alkali solution to a boiling state to obtain a second mixture.

[0201] Evaporation mixed liquid unit: The input end of the evaporation mixed liquid unit is fixedly connected to the output end of the dechlorination module, and is used to mix the second mixture with alkali (such as calcium hydroxide or potassium hydroxide) to adjust the pH value and component ratio of the solution to obtain a third mixture, and perform evaporation treatment on the third mixture to obtain caustic soda.

[0202] The safe production control system of caustic soda provided in this embodiment, the whole system works together through multiple highly integrated modules, realizing automation and efficiency from brine preparation to caustic soda production. The brine preparation module ensures the quality and stability of the raw brine. The electrolysis module adopts a sophisticated acid addition, data acquisition and processing, connection and intelligent control and adjustment mechanism to jointly drive the efficient progress of the electrolysis process. The acid addition unit accurately controls the amount of hydrochloric acid added, and the generated first mixture is electrolyzed in the electrolytic cell; the acquisition unit and the data processing unit work closely together to monitor and optimize the electrolysis conditions in real time; and the control and adjustment unit intelligently controls and adjusts the delivery speed of the first mixture according to the real-time output current data to ensure the maximum electrolysis efficiency. After the electrolysis is completed, the dechlorination module effectively removes chloride ions through advanced chemical or physical methods to ensure the purity of subsequent products. The evaporation module uses mixing and evaporation technology to adjust the pH and concentrate the treated solution, and finally produces high-quality caustic soda. The whole process is closely linked, and each step reflects the precision of technology and the rigor of the process, which not only improves production efficiency, but also ensures the stability and reliability of product quality.

[0203] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A safe production control method for caustic soda, characterized in that: The following steps are involved: Electrolysis: including acid addition, first collection, connection, first control and first electrolysis steps; Acid addition: mixing brine and high-purity hydrochloric acid to obtain a first mixture, and transporting the first mixture to the electrolytic cell; First acquisition: real-time acquisition of current data in the electrolytic cell, processing the current data, and adjusting the output current data of the rectifier according to the processed current data to obtain first data; Establishing a relationship: establishing a corresponding relationship between the first data and the first mixture delivery speed, and establishing a level of the output current data of the rectifier; First control: according to the current output current data of the rectifier, by controlling the opening of the electrolytic cell input valve, the speed of conveying the first mixture to the electrolytic cell is adjusted; First electrolysis: electrolyzing the first mixture to obtain light salt water and light alkali solution; Dechlorination: includes the second control and chloride ion removal steps; Second control: adjusting the output speed of the dilute brine by controlling the opening of the first output valve of the electrolytic cell; Removing chloride ions: sending the dilute brine into a vacuum dechlorination tower to remove chloride ions in the dilute brine; Evaporation: including the third control, heating and evaporation steps of the mixed liquid; The third control: adjusting the output speed of the diluted alkali solution by controlling the opening of the second output valve of the electrolytic cell; Heating: heating the weak alkali solution to a boiling state to obtain a second mixture; Evaporating the mixed liquid: mixing the second mixture with alkali to obtain a third mixture, and evaporating the third mixture to obtain caustic soda; The first control step includes: second collection, first judgment, fourth control and fifth control steps; Second collection: collect the current output current data of the rectifier; First judgment: judging whether the output current data is lower than a preset threshold value, if so, executing the fourth control step; if not, executing the fifth control step; The fourth control includes the first adjustment, the second adjustment and the second judgment steps; First adjustment: increasing the output current data with a preset iteration step length, recorded as the second data; Second adjustment: increasing the conveying speed of the first mixture according to the second data; Second judgment: judging whether the second data is greater than the preset maximum target current data, if so, executing the second acquisition step; if not, executing the first adjustment step; The fifth control includes the third adjustment, the fourth adjustment and the third judgment step; Third adjustment: reducing the output current data with a preset iteration step length, recorded as the third data; Fourth adjustment: reducing the conveying speed of the first mixture according to the third data; Third judgment: judge whether the third data is less than the preset minimum target current data, if so, execute the second acquisition step; if not, execute the third adjustment step.

2. The safe production control method of caustic soda according to claim 1, characterized in that: After executing the first judging step and before executing the fourth controlling step, the method further includes: First acquisition level: obtain the level to which the current output current data of the rectifier belongs, recorded as the first level, and obtain the previous level of the first level, recorded as the second level; First acquisition threshold difference: acquiring the threshold difference of the second level, recorded as the first threshold difference, acquiring an integer multiple of the first threshold difference, recorded as the fourth data, and using the fourth data as the new preset maximum target current data; The calculation model of the first threshold difference is: A=BC; Among them, A is the first threshold difference; B is the upper limit of the second level; C is the lower limit of the second level.

3. The safe production control method of caustic soda according to claim 2, characterized in that: After executing the fourth control step and before executing the fifth control step, the method further includes: Second acquisition level: obtain the level to which the current output current data of the rectifier belongs, recorded as the third level, and obtain the next level of the third level, recorded as the fourth level; Second acquisition threshold difference: acquiring the threshold difference of the fourth level, recorded as the second threshold difference, acquiring the integer multiple of the second threshold difference, recorded as the fifth data, and using the fifth data as the new preset minimum target current data; The calculation model of the second threshold difference is: D = EF; Among them, D is the second threshold difference; E is the upper limit of the fourth level; F is the lower limit of the fourth level.

4. The safe production control method of caustic soda according to claim 3, characterized in that: After executing the third adjustment step and before executing the fourth adjustment step, the method further includes: Setting a safety threshold: Preset a safety threshold, calculate the sum of the third data and the safety threshold, and use the sum of the third data and the safety threshold as new third data.

5. The safe production control method of caustic soda according to claim 4, characterized in that: After executing the fourth adjusting step and before executing the third judging step, the method further includes: Calculation: Subtract the safety threshold from the third data to obtain sixth data, and use the sixth data as new third data.

6. The safe production control method for caustic soda according to any one of claims 1 to 5, characterized in that: Prior to the electrolysis step, it also includes: First preparation: preparing brine, filtering the brine to obtain first brine; Second preparation: transport the heated first brine to a resin tower to remove calcium ions and magnesium ions to obtain second brine, and use the second brine as new brine.

7. The safe production control method for caustic soda according to any one of claims 1 to 5, characterized in that: After performing the first electrolysis step and before performing the dechlorination step, the method further comprises: Monitoring: monitoring the pH value of the first mixture in the electrolytic cell in real time to obtain a first pH value; Fourth judgment: judging whether the first pH value exceeds a preset threshold value, if so, executing the fifth adjustment step; if not, executing the monitoring step; Fifth adjustment: adding hydrochloric acid to the first mixture and performing a monitoring step.

8. The safe production control method of caustic soda according to claim 7, characterized in that: After executing the fourth determining step and before executing the fifth adjusting step, the method further includes: Data collection: collecting historical pH value deviations and historical pH value deviation change rates, and processing the historical pH value deviations and historical pH value deviation change rates respectively, and recording them as the seventh data and the eighth data respectively; Building a database: Building a fuzzy rule database, wherein the fuzzy rule database stores: the seventh data, the eighth data, and the adjustment strategy of the PID controller parameters; Data processing: processing the first pH value to obtain a second pH value; Data comparison: comparing the second pH value with the reference pH value to obtain the pH value deviation and the pH value deviation change rate; Data conversion: convert pH value deviation and pH value deviation change rate into fuzzy linguistic variables; Fuzzy reasoning: According to the fuzzy language variables and adjustment strategies, fuzzy reasoning is performed on the PID controller parameters to obtain the adjustment amount of the PID controller parameters; Parameter adjustment: adjust the PID controller parameters according to the adjustment amount, and output the amount of hydrochloric acid added.

9. A safe production control system for caustic soda, the control system being applicable to the control method according to any one of claims 1 to 8, characterized in that: include: A brine preparation module, used for preparing brine; The electrolysis module is fixedly connected to the brine preparation module, and includes: an acid adding unit, a collection unit, a data processing unit, a connection unit, a first control and regulation unit, and an electrolysis unit; an acid adding unit, used for adding high-purity hydrochloric acid to the brine to obtain a first mixture, and conveying the first mixture to the electrolytic cell; A collection unit, used for collecting current data in the electrolytic cell in real time; A data processing unit, used to process the current data collected by the collection unit, and adjust the output current data of the rectifier according to the processed current data, which is recorded as the first data; A connection unit, used to establish a corresponding relationship between the first data and the first mixture delivery speed, and to establish a level of the output current data of the rectifier; A first control and adjustment unit, used to control the opening of the electrolytic cell input valve and adjust the transmission speed of the first mixture according to the output current data of the rectifier; Electrolysis unit: used for electrolyzing the first mixture to obtain light salt water and light alkali solution; Dechlorination module: including the second control and regulation unit and the chloride ion removal unit; A second control and regulation unit, used to control the opening of the first output valve of the electrolytic cell and regulate the output speed of the dilute brine; A chloride ion removal unit is used to send the dilute brine into a vacuum dechlorination tower to remove chloride ions in the dilute brine; Evaporation module: including a third control unit, a heating unit and an evaporation mixed liquid unit; The third control unit is used to control the opening of the second output valve of the electrolytic cell and adjust the output speed of the diluted alkali solution; A heating unit is used to heat the weak alkali solution to a boiling state to obtain a second mixture; Evaporation mixed liquid unit: used for mixing the second mixture with alkali to obtain a third mixture, and evaporating the third mixture to obtain caustic soda.

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