Method and system for determining film changing time of electrolytic bath for chlor-alkali production

Abstract

The invention provides a method and a system for determining membrane replacement time of an electrolytic bath for chlor-alkali production, and belongs to the technical field of chlor-alkali production. The method comprises the following steps: S1, acquiring influence factors of ionic membrane replacement time; s2, establishing an ionic membrane replacement time prediction model based on the influence factors of the ionic membrane replacement time; and S3, determining the membrane replacement time of the electrolytic bath for chlor-alkali production according to the ionic membrane replacement time prediction model. According to the actual condition of chlor-alkali production, the membrane replacement cost, the electricity consumption per ton of alkali and the start-stop cost are comprehensively considered, so that the replacement time of the ionic membrane is determined more reasonably, and the optimal membrane replacement time when the benefit is maximized is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of chlor-alkali production, and relates to electrolysis technology in chlor-alkali production, and specifically to a method and system for determining membrane replacement time of an electrolytic cell for chlor-alkali production. Background Art

[0002] The chlor-alkali industry is a high-energy-consuming industry. Energy-saving and consumption-reducing technologies for the chlor-alkali industry are currently a hot topic of research. The equipment that consumes the most energy in the chlor-alkali production process is the electrolyzer. With the continuous deepening of technical research, energy-saving and consumption-reducing technologies for electrolyzers are emerging in an endless stream, such as: depolarized oxygen cathode technology, ceramic membrane technology, and zero-electrode distance ion exchange membrane technology, which have reached a very mature stage and have played a very good role in energy saving and consumption reduction in chlor-alkali production.

[0003] Among all the components in the electrolytic cell, the ion membrane is the most expensive. The longer the ion membrane is used, the lower the equipment consumption in the production cost will be. However, as the use time of the ion membrane increases, the selective permeability of the ion membrane will decrease, the permeability of the ion membrane will also decrease, the resistance of the ion membrane will increase, the cell voltage of the electrolytic cell will increase, the current efficiency will gradually decrease, and the power consumption per ton of caustic soda in the production of caustic soda will slowly continue to increase. If the ion membrane is used excessively for a long time, the power consumption per ton of chlor-alkali produced will be too high, the energy consumption will increase, the various costs of chlor-alkali production will increase significantly, and even some solid alkali devices will leak. The mass fraction of chlorate in chlor-alkali will increase, which will not only affect the quality of the chlor-alkali products, but also affect the safe and stable operation of the solid alkali device.

[0004] In summary, in chlor-alkali production, it is very important to determine the replacement time of the ion membrane in the electrolytic cell. How to reasonably determine the replacement time of the ion membrane according to the actual situation in the chlor-alkali production process is a technical problem that skilled technicians urgently need to solve. Summary of the invention

[0005] In view of the technical problem described in the above background technology, there is a technical problem of how to reasonably determine the replacement time of the ion membrane according to the actual situation in the chlor-alkali production process. To solve this technical problem, the present invention proposes a method and system for determining the membrane replacement time of an electrolytic cell for chlor-alkali production.

[0006] When determining the replacement time of the ion membrane, the present invention comprehensively considers the membrane replacement cost, the power consumption per ton of alkali and the start-up and shutdown costs according to the actual situation of chlor-alkali production, so that the replacement time of the ion membrane is determined more reasonably and the optimal membrane replacement time when the benefits are maximized is obtained.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production, comprising the following steps:

[0009] S1: Obtain the influencing factors of the ion membrane replacement time, wherein the influencing factors include: the cost of one membrane replacement, the total amount of chlor-alkali production and the cost of one startup and shutdown;

[0010] S2: Establish an ion membrane replacement time prediction model based on the influencing factors of ion membrane replacement time:

[0011]

[0012] Wherein, y is the average monthly cost of membrane replacement, unit: yuan / month; Q is the cost of membrane replacement, unit: yuan; t is time, unit: month; J is the total amount of chlor-alkali production, unit: ton; E is the electricity cost required to produce one ton of chlor-alkali, unit: yuan / ton; C is the cost required for one start-up and shutdown, unit: yuan; X3(t) is the average monthly cost of membrane replacement, unit: yuan / month; X4(t) is the average monthly cost of electricity consumption per ton of alkali, unit: yuan / month; X5(t) is the average monthly cost of start-up and shutdown, unit: yuan / month;

[0013] S3: Determine the membrane replacement time for the electrolytic cell used in chlor-alkali production based on the ion membrane replacement time prediction model.

[0014] It is further defined that the ion membrane replacement time prediction model also includes constraint condition 1:

[0015] X 2min ≤X2(t)≤X 2max

[0016] Where X2(t) is the inlet acidity of the electrolytic cell, dimensionless; t is time, unit: month; A is the average use time of the electrolytic cell, unit: month, value is 20; G is the value of the inlet acidity of the electrolytic cell, dimensionless, value is 3; X 2max is the maximum value of the acidity at the inlet of the electrolytic cell, dimensionless; X 2min It is the minimum value of the acidity at the inlet of the electrolytic cell, dimensionless.

[0017] It is further defined that the ion membrane replacement time prediction model also includes constraint condition 2:

[0018] X1(t)≥90%

[0019]

[0020] Where X1(t) is the current efficiency, dimensionless; P HCl (t) is the monthly consumption of hydrochloric acid, unit: gram equivalent / month; I is the current of the electrolytic cell, unit: ampere; M is the number of unit cells of the electrolytic cell, unit: piece; m is the number of electrolytic cells, unit: piece; S is the conversion coefficient, unit: gram equivalent / (month·ampere), the value is 26.86; is the volume percentage of oxygen in chlorine, dimensionless; η c is the current leakage rate, dimensionless, and takes a constant of 0.6%; Q HCl is the total amount of hydrochloric acid, unit: liter; t is the time, unit: month; C HCl is the mass percentage concentration of hydrochloric acid, dimensionless; ρ HCl is the density of hydrochloric acid, unit: g / L; 36.5 is the HCl gram equivalent, unit: g / g equivalent; is the concentration of hydroxide ions in the supplied brine, unit: gram equivalent / liter; B1 is the total amount of supplied brine, unit: cubic meter; is the concentration of hydrogen ions in the reflux brine, unit: gram equivalent / liter; B2 represents the total amount of reflux brine in time period t, unit: cubic meter.

[0021] It is further defined that the minimum value of the electrolytic cell inlet acidity and the maximum value of the electrolytic cell inlet acidity are both determined based on historical electrolytic cell inlet acidity.

[0022] It is further defined that the average monthly cost generated by ion membrane replacement is input into the LSTM long short-term memory network, and the LSTM long short-term memory network is used for optimization calculation to obtain the optimized average monthly cost of membrane replacement, the average monthly cost of electricity consumption per ton of alkali, and the average monthly cost of start-up and shutdown; among which, the LSTM long short-term memory network is trained using the historical average monthly cost of ion membrane replacement, the historical average monthly cost of membrane replacement, the historical average monthly cost of electricity consumption per ton of alkali, and the historical average monthly cost of start-up and shutdown.

[0023] The present invention discloses a system for determining membrane replacement time of an electrolytic cell for chlor-alkali production, which is applied to the above-mentioned method for determining membrane replacement time of an electrolytic cell for chlor-alkali production, and comprises:

[0024] Data acquisition module: used to obtain the influencing factors of the ion membrane replacement time, where the influencing factors include: the cost of a membrane replacement, the total amount of chlor-alkali production and the cost of a start-up and shutdown;

[0025] Model building module: used to establish the following ion membrane replacement time prediction model based on the influencing factors of ion membrane replacement time:

[0026]

[0027] Wherein, y is the average monthly cost of membrane replacement, unit: yuan / month; Q is the cost of membrane replacement, unit: yuan; t is time, unit: month; J is the total amount of chlor-alkali production, unit: ton; E is the electricity cost required to produce one ton of chlor-alkali, unit: yuan / ton; C is the cost required for one start-up and shutdown, unit: yuan; X3(t) is the average monthly cost of membrane replacement, unit: yuan / month; X4(t) is the average monthly cost of electricity consumption per ton of alkali, unit: yuan / month; X5(t) is the average monthly cost of start-up and shutdown, unit: yuan / month;

[0028] Membrane replacement time determination module: used to determine the membrane replacement time of the electrolytic cell for chlor-alkali production based on the ion membrane replacement time prediction model.

[0029] A storage medium of the present invention stores a program file, and the program file is executed to implement program instructions formed by the above-mentioned method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production.

[0030] An electronic device of the present invention comprises a processor and a memory coupled to each other, wherein the memory is used to store program instructions formed by the above-mentioned method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production;

[0031] The processor is used to execute program instructions stored in the memory.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention discloses a method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production. When determining the replacement time of an ion membrane, the method comprehensively considers the membrane replacement cost, the power consumption per ton of alkali, and the start-up and shutdown costs according to the actual situation of chlor-alkali production, so that the replacement time of the ion membrane is determined more reasonably, and the optimal membrane replacement time when the benefits are maximized is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of a method for determining the membrane replacement time for an electrolytic cell used in chlor-alkali production;

[0035] Figure 2 Schematic diagram of a system for determining membrane replacement time for electrolytic cells used in chlor-alkali production;

[0036] Figure 3 This is a constraint curve diagram obtained by combining the ion membrane replacement time prediction model. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further explained below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited to the implementation modes described below.

[0038] The replacement time of the ion membrane of the electrolytic cell is crucial to the quality of chlor-alkali products, the safe and stable operation of the solid alkali device, and the energy consumption of chlor-alkali production. At present, the standard for replacing particle membranes in most companies is: the current efficiency of the ion membrane is lower than 93%, or the ion membrane has been in use for more than three years. This standard for determining the replacement time of the ion membrane is unreasonable because sometimes the ion membrane has aged before it has been used for three years, resulting in an increase in the voltage of the ion membrane electrolytic cell, a decrease in current efficiency, and an increase in energy consumption; on the contrary, some ion membranes have been used for more than three years, but have not yet aged, and there is no need to replace them. At the same time, when the current efficiency of the ion membrane is lower than 93%, it will have an impact on the quality of chlor-alkali products.

[0039] When determining the replacement time of the ion membrane, the present invention comprehensively considers the membrane replacement cost, the power consumption per ton of alkali and the start-up and shutdown costs according to the actual situation of chlor-alkali production, and takes the current efficiency and the acidity of the electrolytic cell inlet as constraints, so that the replacement time of the ion membrane is determined more reasonably.

[0040] Current efficiency represents the utilization rate of electric energy. The higher the current efficiency, the higher the utilization rate of electric energy. On the contrary, the lower the current efficiency, the lower the utilization rate of electric energy. Therefore, considering the energy consumption problem in the chlor-alkali production process, the current efficiency must be controlled.

[0041] Acidity at the inlet of the electrolytic cell: The purpose of adding acid to the electrolytic cell is to neutralize the hydroxide ions that migrate back from the cathode chamber, which can reduce side reactions, reduce the oxygen content in chlorine and the content of chlorate in the brine. However, after the ion membrane has been running for a period of time, as the performance of the ion membrane decreases, the amount of acid added to the electrolytic cell will gradually increase. Excessive acidity will cause blisters in the ion membrane, causing mechanical damage to the ion membrane and affecting the production quality of chlor-alkali. Therefore, the acidity at the inlet of the electrolytic cell is also one of the important factors affecting whether the ion membrane needs to be replaced.

[0042] Membrane replacement costs: Membrane replacement costs include the cost of purchasing ion membranes, the cost of electrolytic cell gaskets, and labor costs. For manufacturers, the economic efficiency of membrane replacement is also one of the factors that must be considered. If the membrane is replaced too frequently, the production cost will increase. Therefore, membrane replacement costs are also one of the important factors affecting the replacement time of ion membranes.

[0043] The higher the electricity consumption per ton of alkali, the higher the energy consumption of chlor-alkali production will be, and the cost of chlor-alkali production will also be increased. Therefore, the electricity consumption per ton of alkali is also one of the important factors affecting the replacement time of ion membrane.

[0044] Start-up and shutdown costs: The ion membrane needs to be shut down when it is replaced. However, multiple starts and stops will seriously affect the service life of the electrolyzer. Taking a 300kA electrolyzer as an example, the average service life is 2,300 days, and the daily cost is about 326 yuan. After multiple starts, the cell life is shortened by 700 days, and the daily cost is about 470 yuan, which increases the cost of using the electrolyzer. In addition, the temporary stagnation of production due to start-up and shutdown, as well as the substandard product quality when the machine is just started, will increase the cost of start-up and shutdown. Therefore, the start-up and shutdown costs are also one of the important factors affecting the replacement time of the ion membrane.

[0045] Example 1

[0046] See also Figure 1 The present embodiment provides a method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production, comprising the following steps:

[0047] S1: Obtain the influencing factors of the ion membrane replacement time, wherein the influencing factors include: the cost of one membrane replacement, the total amount of chlor-alkali production and the cost of one startup and shutdown;

[0048] S2: Based on the factors affecting the ion membrane replacement time, the following ion membrane replacement time prediction model is established:

[0049]

[0050] Wherein, y is the average monthly cost of ion membrane replacement, unit: yuan / month, and its value can be taken as the minimum value based on historical data; Q is the cost required for one membrane replacement, unit: yuan; t is time: unit: month; J is the total amount of chlor-alkali production, unit: ton; E is the electricity cost required to produce one ton of chlor-alkali, unit: yuan / ton; C is the cost required for one start-up and shutdown, unit: yuan; X3(t) is the average monthly cost of membrane replacement, unit: yuan / month; X4(t) is the average monthly cost of electricity consumption per ton of alkali, unit: yuan / month; X5(t) is the average monthly cost of start-up and shutdown, unit: yuan / month;

[0051] S3: Determine the membrane replacement time for the electrolytic cell used in chlor-alkali production based on the ion membrane replacement time prediction model.

[0052] In the present invention, the ion membrane replacement time prediction model also includes constraint condition 1:

[0053] X 2min ≤X2(t)≤X 2max

[0054] Where X2(t) is the inlet acidity of the electrolytic cell, dimensionless; t is time, unit: month; A is the average use time of the electrolytic cell, unit: month, value is 20; G is the value of the inlet acidity of the electrolytic cell, dimensionless, value is 3; X 2max is the maximum value of the acidity at the inlet of the electrolytic cell, dimensionless; X 2minIt is the minimum value of the acidity at the inlet of the electrolytic cell, dimensionless.

[0055] In the present invention, the ion membrane replacement time prediction model also includes constraint condition 2:

[0056] X1(t)≥90%

[0057]

[0058] Where X1(t) is the current efficiency, dimensionless; P HCl (t) is the monthly consumption of hydrochloric acid, unit: gram equivalent / month; I is the current of the electrolytic cell, unit: ampere; M is the number of unit cells of the electrolytic cell, unit: piece; m is the number of electrolytic cells, unit: piece; S is the conversion coefficient, unit: gram equivalent / (month·ampere), the value is 26.86; is the volume percentage of oxygen in chlorine, dimensionless; η c is the current leakage rate, dimensionless; Q HCl is the total amount of hydrochloric acid, unit: liter; t is the time, unit: month; C HCl is the mass percentage concentration of hydrochloric acid; ρ HCl is the density of hydrochloric acid, unit: g / L; 36.5 is the HCl gram equivalent, unit: g / g equivalent; is the concentration of hydroxide ions in the supplied brine, unit: gram equivalent / liter; B1 is the total amount of supplied brine, unit: cubic meter; is the concentration of hydrogen ions in the reflux brine, unit: gram equivalent / liter; B2 represents the total amount of reflux brine in time period t, unit: cubic meter.

[0059] Among them, the current efficiency is determined based on the consumption of hydrochloric acid. The calculation principle of the current efficiency is: in the electrolysis process of chlor-alkali, the selective permeability of the ion membrane is not absolute. There will inevitably be a part of the hydroxide ions that pass through the ion membrane to reach the anode chamber. The hydroxide ions in the anode chamber will consume part of the hydrochloric acid, resulting in the consumption of hydrochloric acid to neutralize the supply of brine. The remaining hydroxide ions and chloride ions will be electrolyzed into oxygen and chlorine. Therefore, the current efficiency can be determined based on the consumption of hydrochloric acid. Specifically, the calculation formula for determining the current efficiency based on the consumption of hydrochloric acid is:

[0060]

[0061] Where X1(t) is the current efficiency, dimensionless; P HCl (t) is the monthly consumption of hydrochloric acid, unit: gram equivalent / month; I is the current of the electrolytic cell, unit: ampere; M is the number of unit cells of the electrolytic cell, unit: piece; m is the number of electrolytic cells, unit: piece; S is the conversion coefficient, unit: gram equivalent / (month·ampere), the value is 26.86; is the volume percentage of oxygen in chlorine, dimensionless, and taken as a constant of 0.6%; η c is the current leakage rate, dimensionless.

[0062] In the above formula, the monthly consumption of hydrochloric acid is P HCL (t) Includes the consumption of hydrochloric acid in chlor-alkali production, the consumption of hydrochloric acid used to neutralize the supplied brine, and the content of hydrochloric acid in the reflux brine.

[0063]

[0064] Where P HCl (t) is the monthly consumption of hydrochloric acid, unit: liter / month; Q HCl is the total amount of hydrochloric acid, unit: liter; t is the time, unit: month; C HCl is the mass percentage concentration of hydrochloric acid, dimensionless; ρ HCl is the density of hydrochloric acid, unit: g / L; 36.5 is the HCl gram equivalent, unit: g / g equivalent; is the concentration of hydroxide ions in the supplied brine, unit: gram equivalent / liter; B1 is the total amount of supplied brine, unit: cubic meter; is the concentration of hydrogen ions in the reflux brine, unit: gram equivalent / liter; B2 represents the total amount of reflux brine in time period t, unit: cubic meter.

[0065] In the formula, (Q HCL (t)×C HCL ×ρ HCL ÷36.5) represents the consumption of hydrochloric acid in the production of chlor-alkali; Indicates the consumption of hydrochloric acid for neutralizing the supplied brine; Indicates the hydrochloric acid content in the reflux brine.

[0066] In the present invention, the minimum value of the electrolytic cell inlet acidity and the maximum value of the electrolytic cell inlet acidity are determined based on the historical electrolytic cell inlet acidity, and the maximum value and the minimum value of the historical electrolytic cell inlet acidity are taken respectively. In general, X 2max =5,X 2min =2. In the historical electrolytic cell inlet acidity, X 2min Generally it will not be less than 2, otherwise the hydrogen ions will replace the ions in the hydroxy acid layer of the cathode of the ion membrane, causing the migration ability of potassium ions to decrease and destroying the conductivity of the ion membrane.

[0067] The operating load of the chlor-alkali plant is directly related to the electricity consumption in the production of soda ash. Changes in load will lead to corresponding changes in electricity consumption.

[0068] The relationship between current and voltage follows Faraday's law. Current is proportional to output, and the higher the voltage, the higher the power consumption, which is basically proportional. The higher the current, the higher the cell pressure of the electrolyzer. The output is only related to the current and current efficiency, while the power consumption is also related to the voltage and voltage efficiency. Generally speaking, the current efficiency of the ion membrane can reach 95.5% in the initial stage. As the ion membrane is used for a longer time, the current efficiency will decrease.

[0069] The present invention also includes optimizing and calculating the input value (the average monthly cost of ion membrane replacement) and the output value (the average monthly cost of membrane replacement, the average monthly cost of ton of alkali electricity consumption, and the average monthly cost of start-up and shutdown) in the ion membrane replacement time prediction model through the LSTM long short-term memory network, specifically:

[0070] See also Figure 3 , the monthly average cost of ion membrane replacement is input into the LSTM long short-term memory network, and the LSTM long short-term memory network is used for optimization calculation to obtain the optimized monthly average cost of membrane replacement, the monthly average cost of electricity consumption per ton of alkali, and the monthly average cost of start-up and shutdown; wherein, the LSTM long short-term memory network is trained using the monthly average cost of historical ion membrane replacement, the monthly average cost of historical membrane replacement, the monthly average cost of historical electricity consumption per ton of alkali, and the monthly average cost of historical start-up and shutdown. The sample data formed by the monthly average cost of historical ion membrane replacement, the sample data formed by the monthly average cost of historical membrane replacement, the sample data formed by the monthly average cost of historical electricity consumption per ton of alkali, and the sample data formed by the monthly average cost of historical start-up and shutdown are all no less than 100. As a preferred embodiment of the present invention, the sample data formed by the monthly average cost of historical ion membrane replacement, the sample data formed by the monthly average cost of historical membrane replacement, the sample data formed by the monthly average cost of historical electricity consumption per ton of alkali, and the sample data formed by the monthly average cost of historical start-up and shutdown are all 100.

[0071] Example 2

[0072] See also Figure 2 The present embodiment provides a system for determining the membrane replacement time of an electrolytic cell for chlor-alkali production, which is applied to the method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production in embodiment 1, and comprises:

[0073] Data acquisition module: used to obtain the influencing factors of the ion membrane replacement time, where the influencing factors include: the cost of a membrane replacement, the total amount of chlor-alkali production and the cost of a start-up and shutdown;

[0074] Model building module: used to establish the following ion membrane replacement time prediction model based on the influencing factors of ion membrane replacement time:

[0075]

[0076] Wherein, y is the average monthly cost of membrane replacement, unit: yuan / month; Q is the cost of membrane replacement, unit: yuan; t is time, unit: month; J is the total amount of chlor-alkali production, unit: ton; E is the electricity cost required to produce one ton of chlor-alkali, unit: yuan / ton; C is the cost required for one start-up and shutdown, unit: yuan; X3(t) is the average monthly cost of membrane replacement, unit: yuan / month; X4(t) is the average monthly cost of electricity consumption per ton of alkali, unit: yuan / month; X5(t) is the average monthly cost of start-up and shutdown, unit: yuan / month;

[0077] Membrane replacement time determination module: used to determine the membrane replacement time of the electrolytic cell for chlor-alkali production based on the ion membrane replacement time prediction model.

[0078] The membrane replacement time determination system for the electrolytic cell for chlor-alkali production in this embodiment corresponds to the membrane replacement time determination method for the electrolytic cell for chlor-alkali production in Example 1. Specifically, for the contents of the data acquisition module, the model building module and the membrane replacement time determination module, please refer to the description of the membrane replacement time determination method for the electrolytic cell for chlor-alkali production in Example 1.

[0079] Example 3

[0080] This embodiment provides a storage medium storing a program file, wherein the program file is executed to implement program instructions formed by the method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production in Embodiment 1.

[0081] The storage medium in this embodiment may specifically include random access memory (RAM), internal memory, read-only memory (ROM), programmable ROM, erasable programmable ROM, register, hard disk, removable disk or CD-ROM. It should be noted that those skilled in the art may specifically select the form and type of storage medium according to actual production and use requirements, and this is not further limited in this embodiment.

[0082] Example 4

[0083] This embodiment is an electronic device, including a processor and a memory coupled to each other, wherein the memory is used to store program instructions formed by the method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production in Example 1; and the processor is used to execute the program instructions stored in the memory.

[0084] The electronic device in this embodiment includes any electronic device that can execute program instructions, such as a computer, a mobile terminal or a wearable device.

[0085] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the present invention.

Claims

1. A method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production, characterized in that: The following steps are involved: S1: Obtain the influencing factors of the ion membrane replacement time, wherein the influencing factors include: the cost of one membrane replacement, the total amount of chlor-alkali production and the cost of one startup and shutdown; S2: Establish an ion membrane replacement time prediction model based on the influencing factors of ion membrane replacement time: Wherein, y is the average monthly cost of membrane replacement, unit: yuan / month; Q is the cost of membrane replacement, unit: yuan; t is time, unit: month; J is the total amount of chlor-alkali production, unit: ton; E is the electricity cost required to produce one ton of chlor-alkali, unit: yuan / ton; C is the cost required for one start-up and shutdown, unit: yuan; X3(t) is the average monthly cost of membrane replacement, unit: yuan / month; X4(t) is the average monthly cost of electricity consumption per ton of alkali, unit: yuan / month; X5(t) is the average monthly cost of start-up and shutdown, unit: yuan / month; S3: Determine the membrane replacement time for the electrolytic cell used in chlor-alkali production based on the ion membrane replacement time prediction model.

2. The method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production according to claim 1, characterized in that: The ion membrane replacement time prediction model also includes constraint condition 1: X 2min ≤X2(t)≤X 2max Where X2(t) is the inlet acidity of the electrolytic cell, dimensionless; t is time, unit: month; A is the average use time of the electrolytic cell, unit: month, value is 20; G is the value of the inlet acidity of the electrolytic cell, dimensionless, value is 3; X 2max is the maximum value of the acidity at the inlet of the electrolytic cell, dimensionless; X 2min It is the minimum value of the acidity at the inlet of the electrolytic cell, dimensionless.

3. The method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production according to claim 2, characterized in that: The ion membrane replacement time prediction model also includes constraint condition 2: X1(t)≥90% Where X1(t) is the current efficiency, dimensionless; P HCl (t) is the monthly consumption of hydrochloric acid, unit: gram equivalent / month; I is the current of the electrolytic cell, unit: ampere; M is the number of unit cells of the electrolytic cell, unit: piece; m is the number of electrolytic cells, unit: piece; S is the conversion coefficient, unit: gram equivalent / (month·ampere), the value is 26.86; is the volume percentage of oxygen in chlorine, dimensionless; η c is the current leakage rate, dimensionless, and its value is 0.6%; Q HCl is the total amount of hydrochloric acid, unit: liter; t is time: unit: month; C HCl is the mass percentage concentration of hydrochloric acid, dimensionless; ρ HCl is the density of hydrochloric acid, unit: g / L; 36.5 is the HCl gram equivalent, unit: g / g equivalent; is the concentration of hydroxide ions in the supplied brine, unit: gram equivalent / liter; B1 is the total amount of supplied brine, unit: cubic meter; is the concentration of hydrogen ions in the reflux brine, unit: gram equivalent / liter; B2 represents the total amount of reflux brine in time period t, unit: cubic meter.

4. The method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production according to claim 2, characterized in that: The minimum value of the electrolytic cell inlet acidity and the maximum value of the electrolytic cell inlet acidity are both determined based on the historical electrolytic cell inlet acidity.

5. The method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production according to claim 1, characterized in that: The monthly average cost of ion membrane replacement is input into the LSTM long short-term memory network, and the LSTM long short-term memory network is used for optimization calculation to obtain the optimized monthly average cost of membrane replacement, the monthly average cost of electricity consumption per ton of alkali, and the monthly average cost of start-up and shutdown; among them, the LSTM long short-term memory network is trained using the historical monthly average cost of ion membrane replacement, the historical monthly average cost of membrane replacement, the historical monthly average cost of electricity consumption per ton of alkali, and the historical monthly average cost of start-up and shutdown.

6. A system for determining the membrane replacement time of an electrolytic cell for chlor-alkali production, applied to the method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production according to claim 1, characterized in that: include: Data acquisition module: used to obtain the influencing factors of the ion membrane replacement time, where the influencing factors include: the cost of a membrane replacement, the total amount of chlor-alkali production and the cost of a start-up and shutdown; Model building module: used to establish the following ion membrane replacement time prediction model based on the influencing factors of ion membrane replacement time: Wherein, y is the average monthly cost of membrane replacement, unit: yuan / month; Q is the cost of membrane replacement, unit: yuan; t is time, unit: month; J is the total amount of chlor-alkali production, unit: ton; E is the electricity cost required to produce one ton of chlor-alkali, unit: yuan / ton; C is the cost required for one start-up and shutdown, unit: yuan; X3(t) is the average monthly cost of membrane replacement, unit: yuan / month; X4(t) is the average monthly cost of electricity consumption per ton of alkali, unit: yuan / month; X5(t) is the average monthly cost of start-up and shutdown, unit: yuan / month; Membrane replacement time determination module: used to determine the membrane replacement time of the electrolytic cell for chlor-alkali production based on the ion membrane replacement time prediction model.

7. A storage medium, characterized in that: A program file is stored, and the program file is executed to implement program instructions formed by the method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production as described in any one of claims 1-5.

8. An electronic device, characterized in that: The method comprises a processor and a memory coupled to each other, wherein the memory is used to store program instructions formed by the method for determining the membrane replacement time of an electrolytic cell for chlor-alkali production according to any one of claims 1 to 5; The processor is used to execute program instructions stored in the memory.

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