Control method, device and equipment for caustic soda production and storage medium

Abstract

The invention provides a caustic soda production control method, device and equipment and a storage medium, and the method comprises the following steps: when first production data meets a preset production starting condition, preparing saline water; when the concentration of the saline water reaches a preset concentration, carrying out load-increasing linkage control on an electrolytic bath, a chlorine compressor and a hydrogen compressor; the electrolytic bath is used for electrolyzing the saline water to obtain sodium hydroxide, hydrogen and chlorine, the chlorine compressor is used for liquefying the chlorine, and the hydrogen compressor is used for treating the hydrogen; when the purity of the hydrogen and the purity of the chlorine reach the preset purity, the hydrogen and the chlorine are used for hydrochloric acid synthesis. According to the method, caustic soda production is automatically carried out according to production data, linkage control is carried out on all parts in the production process, and automatic starting and stopping and load changing of caustic soda industrial production are achieved.

Description

Technical Field

[0001] This application relates to the technical field of caustic soda preparation, and particularly to a control method, device, equipment and storage medium for caustic soda production. Background Art

[0002] Caustic soda, also known as sodium hydroxide, is a white solid at room temperature, with strong corrosiveness, easily soluble in water, and its aqueous solution is strongly alkaline. It is a very commonly used base. In industry, sodium hydroxide, chlorine, hydrogen and other products are usually produced by electrolyzing sodium chloride solution through a direct current in an ion-exchange membrane electrolytic cell.

[0003] However, the production process of caustic soda is long, the start-up and shutdown take a long time, and the process control points are complex and diverse. Especially during the start-up and shutdown and the process of changing load during normal operation, there are many system interlocks, and the requirements for the smoothness of system start-up and shutdown and load change are relatively high. Over the years, although DCS control has been achieved in the control process of caustic soda plants, the degree of automation is low, and the self-control operation rate is less than 50%. The start-up and shutdown and load change operations are all manually performed on the DCS. Mistakes often cause unplanned shutdowns, and the losses caused by misoperation accidents rank first. Summary of the Invention

[0004] In view of this, the embodiments of this application provide a control method, device, equipment and storage medium for caustic soda production to achieve automatic start-up and shutdown of caustic soda production.

[0005] In a first aspect, the embodiments of this application provide a control method for caustic soda production, including:

[0006] When the first production data meets the preset production start condition, prepare brine;

[0007] When the concentration of the brine reaches the preset concentration, perform a load increase linkage control on the electrolytic cell, chlorine compressor and hydrogen compressor; the electrolytic cell is used to electrolyze the brine to obtain sodium hydroxide, hydrogen and chlorine, the chlorine compressor is used to liquefy chlorine, and the hydrogen compressor is used to process hydrogen;

[0008] When the purity of hydrogen and the purity of chlorine reach the preset purity, use hydrogen and chlorine for hydrochloric acid synthesis.

[0009] Optionally, the performing a load increase linkage control on the electrolytic cell, chlorine compressor and hydrogen compressor includes:

[0010] Control the electrolytic current of the electrolytic cell to rise to the first target current, and control the production parameters of the electrolytic cell;

[0011] Use the chlorine compressor reflux double regulating valve in the chlorine compressor to dynamically adjust the internal pressure of the chlorine compressor according to the chlorine inlet pressure of the chlorine compressor, and dynamically adjust the chlorine temperature according to the chlorine outlet pressure of the chlorine compressor;

[0012] Control the load currents of at least two of the hydrogen compressors to be the same, and dynamically adjust the internal pressure and the liquid level height of the hydrogen compressors.

[0013] Optionally, controlling the production parameters of the electrolytic cell includes:

[0014] Increase the flow rate of brine flowing into the electrolytic cell according to the electrolysis current; increase the flow rate of hydrochloric acid added to the brine according to the electrolysis current; increase the flow rate of pure water added for alkali concentration according to the electrolysis current; increase the steam temperature in the electrolytic cell according to the electrolysis current; control the chlorine-hydrogen pressure difference according to the electrolysis current; control the flow rate into the resin tower according to the brine level.

[0015] Optionally, when stopping the production of caustic soda, the method further includes:

[0016] When the second production data meets the preset production stop conditions, perform a load reduction interlock control on the electrolytic cell, the chlorine compressor, and the hydrogen compressor;

[0017] Control nitrogen to be filled into the anode and cathode tank heads of the electrolytic cell, and stop the synthesis of hydrochloric acid;

[0018] When the electrolysis current drops to 0, control the chlorine compressor and the hydrogen compressor to stop working;

[0019] Control the electrolytic cell to replace chloride ions, and when the chloride ion concentration reaches the preset concentration, control the electrolytic cell to stop working;

[0020] Stop the production of brine.

[0021] Optionally, the performing a load reduction interlock control on the electrolytic cell, the chlorine compressor, and the hydrogen compressor includes:

[0022] Control the electrolysis current of the electrolytic cell to be reduced to a second target current, and control the production parameters of the electrolytic cell;

[0023] Use the chlorine compressor reflux double regulating valve in the chlorine compressor to dynamically adjust the internal pressure of the chlorine compressor according to the chlorine inlet pressure of the chlorine compressor, and dynamically adjust the chlorine temperature according to the chlorine outlet pressure of the chlorine compressor;

[0024] Control the load currents of at least two of the hydrogen compressors to be the same, and dynamically adjust the internal pressure and the liquid level height of the hydrogen compressors.

[0025] Optionally, controlling the production parameters of the electrolytic cell includes:

[0026] Reduce the flow rate of brine flowing into the electrolytic cell according to the electrolysis current; reduce the flow rate of hydrochloric acid added to the brine according to the electrolysis current; reduce the flow rate of pure water added to adjust the alkali concentration according to the electrolysis current; reduce the steam temperature in the electrolytic cell according to the electrolysis current; control the chlorine-hydrogen pressure difference according to the electrolysis current; control the flow rate into the resin tower according to the brine level.

[0027] In a second aspect, an embodiment of the present application provides a control device for caustic soda production, including:

[0028] A brine preparation module, configured to prepare brine when the first production data meets the preset production start condition;

[0029] A linkage control module, configured to perform a load increase linkage control on the electrolytic cell, the chlorine compressor, and the hydrogen compressor when the concentration of the brine reaches the preset concentration; the electrolytic cell is used to electrolyze the brine to obtain sodium hydroxide, hydrogen, and chlorine, the chlorine compressor is used to liquefy chlorine, and the hydrogen compressor is used to process hydrogen;

[0030] A hydrochloric acid synthesis module, configured to synthesize hydrochloric acid using hydrogen and chlorine when the purities of hydrogen and chlorine reach the preset purities.

[0031] Optionally, the linkage control module is specifically configured to:

[0032] Control the electrolysis current of the electrolytic cell to increase to the first target current and control the production parameters of the electrolytic cell;

[0033] Dynamically adjust the internal pressure of the chlorine compressor according to the chlorine inlet pressure of the chlorine compressor using the chlorine compressor reflux double regulating valve in the chlorine compressor, and dynamically adjust the chlorine temperature according to the chlorine outlet pressure of the chlorine compressor;

[0034] Control the load currents of at least two of the hydrogen compressors to be the same, and dynamically adjust the internal pressure and the liquid level height of the hydrogen compressors.

[0035] Optionally, the linkage control module is specifically configured to:

[0036] Increase the flow rate of brine flowing into the electrolytic cell according to the electrolysis current; increase the flow rate of hydrochloric acid added to the brine according to the electrolysis current; increase the flow rate of pure water added to adjust the alkali concentration according to the electrolysis current; increase the steam temperature in the electrolytic cell according to the electrolysis current; control the chlorine-hydrogen pressure difference according to the electrolysis current; control the flow rate into the resin tower according to the brine level.

[0037] Optionally, the device further includes a shutdown module, configured to:

[0038] Perform a load decrease linkage control on the electrolytic cell, the chlorine compressor, and the hydrogen compressor when the second production data meets the preset production stop condition;

[0039] Control the nitrogen gas to be filled into the anode and cathode tank heads of the electrolytic cell, and stop synthesizing hydrochloric acid;

[0040] When the electrolysis current drops to 0, control the chlorine compressor and the hydrogen compressor to stop working;

[0041] Control the electrolytic cell to displace chloride ions, and when the chloride ion concentration reaches the preset concentration, control the electrolytic cell to stop working;

[0042] Stop brine production.

[0043] Optionally, the parking module is specifically configured to:

[0044] Control the electrolysis current of the electrolytic cell to decrease to the second target current, and control the production parameters of the electrolytic cell;

[0045] Use the chlorine compressor reflux double regulating valve in the chlorine compressor to dynamically adjust the internal pressure of the chlorine compressor according to the chlorine inlet pressure of the chlorine compressor, and dynamically adjust the chlorine temperature according to the chlorine outlet pressure of the chlorine compressor;

[0046] Control the load currents of at least two of the hydrogen compressors to be the same, and dynamically adjust the internal pressure and the liquid level height of the hydrogen compressors.

[0047] Optionally, the parking module is specifically configured to:

[0048] Reduce the flow rate of the brine flowing into the electrolytic cell according to the reduction of the electrolysis current; reduce the flow rate of hydrochloric acid added to the brine according to the reduction of the electrolysis current; reduce the flow rate of pure water added with alkali concentration according to the reduction of the electrolysis current; reduce the steam temperature in the electrolytic cell according to the reduction of the electrolysis current; control the chlorine-hydrogen pressure difference according to the electrolysis current; control the flow rate into the resin tower according to the brine level.

[0049] In a third aspect, an embodiment of the present application provides a device, which includes a memory and a processor. The memory is used to store instructions or codes, and the processor is used to execute the instructions or codes so that the device executes the control method for caustic soda production according to any one of the foregoing first aspects.

[0050] In a fourth aspect, an embodiment of the present application provides a computer storage medium, in which codes are stored. When the codes are run, the device running the codes implements the control method for caustic soda production according to any one of the foregoing first aspects.

[0051] An embodiment of the present application provides a control method, device, equipment, and storage medium for caustic soda production. When executing the method, first determine whether the first production data meets the preset production start condition. When the determination result is yes, produce brine. Then, when the concentration of the brine reaches the preset concentration, perform a load increase linkage control on the electrolytic cell, chlorine compressor, and hydrogen compressor. Finally, when the hydrogen purity and chlorine purity reach the preset purity, use hydrogen and chlorine for hydrochloric acid synthesis to achieve automatic control of the caustic soda production process. In this way, by judging the start and stop of caustic soda production based on the first production data and performing linkage control on the electrolytic cell, chlorine compressor, and hydrogen compressor during the production process, automatic start and stop and variable load of caustic soda industrial production are realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] To more clearly illustrate the technical solutions in this embodiment or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0053] Figure 1 It is a control flow chart of caustic soda production provided by an embodiment of the present application;

[0054] Figure 2 It is another control flow chart of caustic soda production provided by an embodiment of the present application;

[0055] Figure 3 It is a schematic diagram of load increase linkage control provided by an embodiment of the present application;

[0056] Figure 4 It is a schematic diagram of caustic soda preparation for starting provided by an embodiment of the present application;

[0057] Figure 5 It is another control flow chart of caustic soda production provided by an embodiment of the present application;

[0058] Figure 6 It is a schematic diagram of load decrease linkage control provided by an embodiment of the present application;

[0059] Figure 7 It is a schematic diagram of caustic soda preparation for stopping provided by an embodiment of the present application;

[0060] Figure 8 It is a schematic diagram of the structure of a control device for caustic soda production provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0061] Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0062] See Figure 1 , Figure 1 which is a control flow chart for caustic soda production provided by an embodiment of the present application, including:

[0063] S101: When the first production data meets the preset production start condition, prepare brine.

[0064] In the embodiment of the present application, the first production data includes the pressure, temperature, and liquid level in the production device, etc., which are specifically used to measure the state of the current production device and determine whether the current production device has the conditions for starting up. The preset production start condition is the production parameters when the production device has the conditions for starting up, such as the control critical values of each process point, which are specifically set by technicians in advance.

[0065] The first production data can be obtained through devices with detection functions such as power equipment, valves, pressure gauges, liquid level gauges, and temperature gauges. The above devices can also be remotely controlled, and communication interfaces can be set for the above devices to receive or send feedback signals such as digital signals, analog signals, analog inputs, or analog outputs.

[0066] Such as Figure 2 shown. Figure 2 which is another control flow chart for caustic soda production provided by an embodiment of the present application.

[0067] Each device communicates through digital signals, analog signals, analog inputs, or analog output communication signals; then set the process PID control loop and the start / stop conditions of the devices; finally, realize the automatic control of each device according to the process PID control loop and the start / stop conditions of the devices.

[0068] In one embodiment, the first production data includes the relevant data of power electricity, direct current, instrument air, compressed air, nitrogen, steam, chilled water, circulating water, and pure water, as well as the data of regular and quantitative feeding of raw and auxiliary chemical raw materials.

[0069] Determining whether the first production data meets the preset production start-up conditions can be as follows: Confirm that the instrument air pressure > 0.5 Mpa; Confirm that the nitrogen pressure > 0.3 Mpa; Confirm that the main steam pipe pressure > 0.2 Mpa; Confirm that the main circulating water pipe pressure > 0.3 Mpa; Confirm that the pure water level > 3000 mm; Confirm that the salt reserve is normal; Select one of the conditions or the Kai membrane system; Confirm that the water distribution tank level > 2800 mm; Confirm that the hydrochloric acid level > 700 mm; Confirm that the sodium hydroxide level > 1100 mm; Confirm that the sodium hypochlorite level > 600 mm; Confirm that the sodium sulfite level > 600 mm; Confirm that the sodium carbonate level > 600 mm.

[0070] When it is determined that the first production data meets the above conditions, start the production of brine.

[0071] In the embodiment of the present application, the production of brine includes the production of primary brine and the production of secondary brine. When starting the production of primary brine, produce primary refined brine; after starting the production of primary brine, start the production of secondary brine to produce secondary refined brine.

[0072] S102: When the concentration of the brine reaches the preset concentration, perform a load increase linkage control on the electrolytic cell, chlorine compressor, and hydrogen compressor.

[0073] The electrolytic cell is used to electrolyze brine to obtain sodium hydroxide, hydrogen, and chlorine. The chlorine compressor is used to liquefy chlorine, and the hydrogen compressor is used to process hydrogen.

[0074] When the brine concentration reaches the preset concentration, the electrolytic cell circulation can be started to heat up, and power is supplied to the electrolytic cell. The electrolytic cell electrolyzes brine to generate caustic soda, hydrogen ions, and chloride ions. Then, pure hydrogen and chlorine are obtained through the chlorine compressor and hydrogen compressor.

[0075] In the embodiment of the present application, the load increase linkage control on the electrolytic cell, chlorine compressor, and hydrogen compressor includes:

[0076] Control the electrolytic current of the electrolytic cell to increase to the first target current, and control the production parameters of the electrolytic cell;

[0077] Use the chlorine compressor reflux double regulating valve in the chlorine compressor to dynamically adjust the internal pressure of the chlorine compressor according to the chlorine inlet pressure of the chlorine compressor, and dynamically adjust the chlorine temperature according to the chlorine outlet pressure of the chlorine compressor;

[0078] Control the load currents of at least two of the hydrogen compressors to be the same, and dynamically adjust the internal pressure and liquid phase level height of the hydrogen compressor.

[0079] The first target current can be the maximum electrolysis current of the electrolytic cell. Before increasing the load, the current increase rate and brine concentration can be retrieved first, and then the target current for increasing the current, that is, the first target current, can be input. During the process of increasing the current, the electrolytic cell, chlorine compressor, and hydrogen compressor are controlled in a linkage manner.

[0080] Control the production parameters of the electrolytic cell and adjust the parameters of the chlorine compressor and hydrogen compressor.

[0081] Specifically, controlling the production parameters of the electrolytic cell includes:

[0082] Increase the flow rate of the brine flowing into the electrolytic cell according to the electrolysis current; increase the flow rate of hydrochloric acid added to the brine according to the electrolysis current; increase the flow rate of pure water added to increase the alkali concentration according to the electrolysis current; increase the steam temperature in the electrolytic cell according to the electrolysis current; control the chlorine-hydrogen pressure difference according to the electrolysis current; control the flow rate into the resin tower according to the brine level.

[0083] As Figure 3 shown, Figure 3 is a schematic diagram of a load increase linkage control provided by an embodiment of the present application. During the process of increasing the load, the flow rate of the brine entering the cell automatically tracks the increase in current load according to the set brine concentration in the navigation; the flow rate of hydrochloric acid added to the dilute brine automatically increases following the current load, and the APC controls the online pH; the flow rate of pure water added to increase the alkali concentration automatically increases following the current load, and the APC controls the online alkali concentration; the steam temperature rise in the electrolytic cell automatically increases following the current load, and the APC controls the minimum difference in the cell temperature of each loop; the current retrieves the stable range of the chlorine-hydrogen pressure difference in a single loop, and automatically selects to pause or start until the target current is reached; the secondary refined brine storage tank automatically increases the flow rate into the resin tower according to the liquid level, and stabilizes the storage volume of the secondary refined brine; when the current increases, the a-angle of the rectifier is automatically controlled in a linkage manner, and the stable angle is between 5 and 20 degrees.

[0084] The chlorine compressor reflux double regulating valve automatically controls following the inlet pressure of the chlorine compressor to stabilize the pressure of the chlorine gas system; the cooling system of the chlorine compressor automatically modifies the set value following the outlet chlorine gas pressure to stabilize the temperature of the compressed chlorine gas.

[0085] The total control PID controls two variable-frequency hydrogen compressors to maintain the same frequency load carrying capacity and stabilize the pressure of the hydrogen gas system; the liquid level interlock function block of the hydrogen compressor gas-liquid separator is started to stably control the height of the liquid phase level.

[0086] It should be noted that the above are all enabled simultaneously in a linkage manner under the same condition of increasing the current load. The above APC is advanced control, which is different from conventional single-loop control and is a general term for better control effects and control strategies than PID control, mainly realizing the automatic control of complex controlled processes.

[0087] S103: When the hydrogen purity and chlorine purity reach the preset purity, use hydrogen and chlorine for hydrochloric acid synthesis.

[0088] When the purity of hydrogen and chlorine reaches the preset purity, the hydrochloric acid synthesis starts. It should be noted that before the hydrochloric acid synthesis, chlorine will also be liquefied by a chlorine compressor.

[0089] The above-mentioned caustic soda production start-up process is as Figure 4 shown, Figure 4 is a schematic diagram of the start-up of caustic soda preparation provided by an embodiment of the present application. When the start-up conditions are met, the primary brine start-up, secondary brine start-up, and brine electrolysis start-up are carried out in sequence, and then the chlorine treatment and hydrogen treatment start simultaneously, and the chlorine liquefaction start-up; finally, the hydrochloric acid synthesis start-up.

[0090] An embodiment of the present application provides a control method for caustic soda production. First, it is judged whether the first production data meets the preset production start conditions. When the judgment result is satisfied, brine is prepared; then, when the concentration of the brine reaches the preset concentration, the electrolytic cell, chlorine compressor, and hydrogen compressor are controlled for load increase linkage control; finally, when the purity of hydrogen and chlorine reaches the preset purity, hydrochloric acid is synthesized using hydrogen and chlorine to realize the automatic control of the caustic soda production process. In this way, by judging the start and stop of caustic soda production according to the first production data and performing linkage control on the electrolytic cell, chlorine compressor, and hydrogen compressor during the production process, the automatic start and stop and variable load of caustic soda industrial production are realized.

[0091] The above embodiment introduces the automatic start-up process of caustic soda production. The following introduces the automatic shutdown process of caustic soda production.

[0092] See Figure 5 , Figure 5 is another control flow chart of caustic soda production provided by an embodiment of the present application. In the embodiment of the present application, when stopping the production of caustic soda, the method further includes:

[0093] S501: When the second production data meets the preset production stop conditions, perform load reduction linkage control on the electrolytic cell, the chlorine compressor, and the hydrogen compressor.

[0094] The preset production stop conditions are the production parameters when the production device has the shutdown conditions.

[0095] Contrary to step S102, when the second production data meets the preset production stop conditions, perform load reduction linkage control on the electrolytic cell, the chlorine compressor, and the hydrogen compressor.

[0096] Specifically, the performing load reduction linkage control on the electrolytic cell, the chlorine compressor, and the hydrogen compressor includes:

[0097] Control the electrolytic current of the electrolytic cell to decrease to the second target current, and control the production parameters of the electrolytic cell;

[0098] Dynamically adjust the internal pressure of the chlorine compressor according to the chlorine inlet pressure of the chlorine compressor by using the chlorine compressor reflux double regulating valve in the chlorine compressor, and dynamically adjust the chlorine temperature according to the chlorine outlet pressure of the chlorine compressor;

[0099] Control the load currents of at least two hydrogen compressors to be the same, and dynamically adjust the internal pressure and the liquid level height of the hydrogen compressors.

[0100] The second target current can be the minimum electrolysis current of the electrolytic cell, usually 0. Before reducing the load, the current increase rate and the brine concentration can be retrieved first, and then the target current for reducing the current, that is, the second target current, can be input. During the process of reducing the current, the electrolytic cell, the chlorine compressor and the hydrogen compressor are controlled in a coordinated manner.

[0101] Control the production parameters of the electrolytic cell, and adjust the parameters of the chlorine compressor and the hydrogen compressor.

[0102] In the embodiment of the present application, the controlling the production parameters of the electrolytic cell includes:

[0103] Reduce the flow rate of the brine flowing into the electrolytic cell according to the electrolysis current; reduce the flow rate of hydrochloric acid added to the brine according to the electrolysis current; reduce the flow rate of pure water added to the alkali concentration according to the electrolysis current; reduce the steam temperature in the electrolytic cell according to the electrolysis current; control the chlorine-hydrogen pressure difference according to the electrolysis current; control the flow rate into the resin tower according to the brine level.

[0104] As Figure 6 shown, Figure 6 is a schematic diagram of a coordinated control for load reduction provided by the embodiment of the present application.

[0105] During the process of reducing the load, the flow rate of the brine entering the cell automatically tracks the current load and reduces the flow rate according to the brine concentration set by the operation navigation software; the flow rate of hydrochloric acid added to the dilute brine automatically reduces following the current load, and the APC controls the online PH; the flow rate of pure water added to the alkali concentration automatically decreases following the current load, and the APC controls the online alkali concentration; the steam temperature rise in the electrolytic cell automatically reduces following the current load, and the APC controls the minimum difference in the cell temperature of each loop; the current retrieves the stable range of the chlorine-hydrogen pressure difference of a single loop, and automatically selects to pause or start until the target current is reached; for the secondary refined brine storage tank, according to the liquid level, the APC automatically reduces the flow rate into the resin tower to stabilize the storage volume of the secondary refined brine; when the current decreases, the a angle of the rectifier is automatically controlled in a coordinated manner, and the stable angle is between 5 and 20 degrees.

[0106] The chlorine compressor reflux double regulating valve automatically controls following the inlet pressure of the chlorine compressor to stabilize the pressure of the chlorine gas system; the chlorine compressor reflux double regulating valve automatically controls following the inlet pressure of the chlorine compressor to stabilize the pressure of the chlorine gas system.

[0107] The master control PID controls two variable-frequency hydrogen compressors to maintain the same frequency and load capacity and stabilize the pressure of the hydrogen system; the liquid-level interlock function block of the hydrogen compressor gas-liquid separator is started to stably control the height of the liquid phase level.

[0108] It should be noted that the above processes are all carried out simultaneously in linkage under the same condition of reducing the current load.

[0109] S502: Control nitrogen to be filled into the anode and cathode heads of the electrolytic cell to stop the synthesis of hydrochloric acid.

[0110] S503: When the electrolytic current drops to 0, control the chlorine compressor and the hydrogen compressor to stop working.

[0111] S504: Control the electrolytic cell to replace chloride ions. When the chloride ion concentration reaches the preset concentration, control the electrolytic cell to stop working.

[0112] S505: Stop the production of brine.

[0113] The above-mentioned start-up process of caustic soda production can be as Figure 7 shown Figure 7 This is a schematic diagram of caustic soda preparation shutdown provided by an embodiment of the present application. When the shutdown conditions are met, the liquefaction of chlorine and the shutdown of hydrochloric acid synthesis are carried out in sequence; then, the chlorine treatment and the hydrogen treatment are shut down simultaneously, and the electrolysis of brine is shut down; finally, the secondary brine shutdown and the primary brine shutdown are carried out in sequence.

[0114] In the embodiment of the present application, the above control functions can be modularized. For example: 1) The automatic control module of the PID loop of the chlorine compressor reflux valve; 2) The automatic control module of the PID loop of the variable-frequency hydrogen compressor circuit; 3) The sequential control function module of the electrolytic cell temperature according to the current load; 4) The automatic control function module of the proportion of adding hydrochloric acid to dilute brine; 5) The automatic control function module of the proportion of the flow rate of brine entering the electrolysis; 6) The automatic control function module of the automatic tracking and adjustment of the caustic liquor concentration according to the current load; 7) The automatic control function module of the proportion of the load change of the synthesis furnace and the absorption water flow rate; 8) The automatic control function module of the material balance flow rate of each storage tank; 9) The sequential control function module of the interlock of the addition amount of raw and auxiliary chemical raw materials. Each function module sets the modification ratio, comparison parameters, and control rate under different load conditions according to process requirements. When automatically adjusting the load during the caustic soda production process, the associated function modules are automatically linked and controlled to achieve a stable and self-operating automatic control effect.

[0115] The present application also provides an embodiment for adjusting the pressure of the chlorine compressor. In the embodiment of the present application, valve A controls the chlorine to enter the chlorine compressor, and valve B controls the chlorine to go to the accident chlorine. The automatic control of valve A and valve B is achieved by setting the target set value, step value, and residence time of valve A and valve B.

[0116] During the startup and shutdown processes, the pressure of the chlorine compressor is controlled by valves A and B to meet the set conditions. The set conditions can be one or more of the following: the deviation between the set value and the actual value of the total chlorine pipeline pressure is within 100 mmH2O; the opening degree of the chlorine-hydrogen differential pressure valve is greater than or equal to 5%; valves A and B are in the automatic state; the set value input value should meet the conditions for pressure increase / decrease; the pressure increase and pressure decrease procedures are prohibited from being used simultaneously; during the pressure increase or pressure decrease process, it is prohibited to modify the set value. Through the above process, the sequence control program, interlock, and shielding functions are fully utilized to avoid misoperations. After starting the caustic soda preparation, the pressure of the chlorine compressor can be increased or decreased by valves A and B to make the pressure of the chlorine compressor meet the set conditions.

[0117] This application also provides an embodiment of automatic temperature rise control for dilute sulfuric acid concentration. In the embodiment of this application, the temperature of the dilute sulfuric acid is measured and controlled by a temperature sensor. It is assumed that the measured temperature of the temperature sensor is T1 °C, and the temperature rise rate is set to T2 °C / s in the temperature sensor in advance. The target temperature set by the temperature sensor is T3 °C, the determined temperature difference is a °C, and the dead zone valve position is b%.

[0118] When T2 °C ≤ 150 °C and (T3 - T2) °C ≤ a °C, the high limit of the temperature sensor is adjusted to 0%. When (T3 - T2) °C > a °C, the high limit of the temperature sensor is adjusted to 100%, and the low limit is b%. When T2 °C > 150 °C, the high limit of the temperature sensor is adjusted to 100%, and the low limit is b%. Based on T1 °C, the temperature of the dilute sulfuric acid is controlled to rise to T3 °C at a rate of T2 °C / s.

[0119] The above are some specific implementation manners of the control method for caustic soda production provided by the embodiments of this application. Based on this, this application also provides a corresponding device. The device provided by the embodiments of this application will be introduced from the perspective of functional modularization below.

[0120] See Figure 8 the structural schematic diagram of the control device 800 for caustic soda production shown. The device 800 includes a brine preparation module 810, a linkage control module 820, and a hydrochloric acid synthesis module 830.

[0121] The brine preparation module 810 is used to prepare brine when the first production data meets the preset production startup conditions;

[0122] The linkage control module 820 is used to perform a load increase linkage control on the electrolytic cell, chlorine compressor, and hydrogen compressor when the concentration of the brine reaches the preset concentration; the electrolytic cell is used to electrolyze the brine to obtain sodium hydroxide, hydrogen, and chlorine, the chlorine compressor is used to liquefy the chlorine, and the hydrogen compressor is used to process the hydrogen;

[0123] The hydrochloric acid synthesis module 830 is used to synthesize hydrochloric acid using hydrogen and chlorine when the purity of hydrogen and the purity of chlorine reach the preset purity.

[0124] An embodiment of the present application provides a control device for caustic soda production. First, it is determined whether the first production data meets the preset production start condition. When the determination result is affirmative, brine is prepared. Then, when the concentration of the brine reaches the preset concentration, a load-up linkage control is performed on the electrolytic cell, the chlorine compressor, and the hydrogen compressor. Finally, when the purity of hydrogen and the purity of chlorine reach the preset purity, hydrochloric acid is synthesized using hydrogen and chlorine to achieve automatic control of the caustic soda production process. In this way, by determining the start and stop of caustic soda production based on the first production data and performing linkage control on the electrolytic cell, the chlorine compressor, and the hydrogen compressor during the production process, automatic start and stop as well as variable load in the industrial production of caustic soda are realized.

[0125] In the embodiment of the present application, the linkage control module 820 is specifically used for:

[0126] Controlling the electrolytic current of the electrolytic cell to increase to the first target current and controlling the production parameters of the electrolytic cell;

[0127] Using the chlorine compressor reflux double regulating valve in the chlorine compressor to dynamically adjust the internal pressure of the chlorine compressor according to the chlorine inlet pressure of the chlorine compressor and dynamically adjust the chlorine temperature according to the chlorine outlet pressure of the chlorine compressor;

[0128] Controlling the load currents of at least two of the hydrogen compressors to be the same and dynamically adjusting the internal pressure and the liquid level height of the hydrogen compressors.

[0129] In the embodiment of the present application, the linkage control module 820 is specifically used for:

[0130] Increasing the flow rate of the brine flowing into the electrolytic cell according to the electrolytic current; increasing the flow rate of hydrochloric acid added to the brine according to the electrolytic current; increasing the flow rate of pure water added to increase the alkali concentration according to the electrolytic current; increasing the steam temperature in the electrolytic cell according to the electrolytic current; controlling the chlorine-hydrogen pressure difference according to the electrolytic current; controlling the flow rate into the resin tower according to the brine level.

[0131] In the embodiment of the present application, the device further includes a stop module, which is used for:

[0132] When the second production data meets the preset production stop condition, performing a load-down linkage control on the electrolytic cell, the chlorine compressor, and the hydrogen compressor;

[0133] Controlling nitrogen to be filled into the anode and cathode tank heads of the electrolytic cell and stopping the synthesis of hydrochloric acid;

[0134] When the electrolytic current drops to 0, controlling the chlorine compressor and the hydrogen compressor to stop working;

[0135] Control the replacement of chloride ions in the electrolytic cell, and when the chloride ion concentration reaches a preset concentration, control the electrolytic cell to stop working;

[0136] Stop brine production.

[0137] In the embodiment of the present application, the parking module is specifically used for:

[0138] Control the electrolytic current of the electrolytic cell to decrease to a second target current, and control the production parameters of the electrolytic cell;

[0139] Use the chlorine compressor reflux double regulating valve in the chlorine compressor to dynamically adjust the internal pressure of the chlorine compressor according to the chlorine inlet pressure of the chlorine compressor, and dynamically adjust the chlorine temperature according to the chlorine outlet pressure of the chlorine compressor;

[0140] Control the load currents of at least two hydrogen compressors to be the same, and dynamically adjust the internal pressure and the liquid level height of the hydrogen compressors.

[0141] In the embodiment of the present application, the parking module is specifically used for:

[0142] Reduce the flow rate of brine flowing into the electrolytic cell according to the reduction of the electrolytic current; reduce the flow rate of hydrochloric acid added to the brine according to the electrolytic current; reduce the flow rate of pure water added to the alkali concentration according to the electrolytic current; reduce the steam temperature in the electrolytic cell according to the electrolytic current; control the chlorine-hydrogen pressure difference according to the electrolytic current; control the flow rate into the resin tower according to the brine level.

[0143] The embodiment of the present application also provides a corresponding device and a computer storage medium for implementing the solution provided by the embodiment of the present application.

[0144] Among them, the device includes a memory and a processor. The memory is used to store instructions or codes, and the processor is used to execute the instructions or codes so that the device executes the control method for caustic soda production described in any embodiment of the present application.

[0145] The computer storage medium stores codes. When the codes are run, the device running the codes implements the control method for caustic soda production described in any embodiment of the present application.

[0146] In the embodiment of the present application, the "first", "second" (if any) in the names such as "first" and "second" are only used as name identifiers and do not represent the first and second in order.

[0147] As can be seen from the description of the above embodiments, those skilled in the art can clearly understand that all or part of the steps in the above embodiment methods can be implemented by means of software plus a general hardware platform. Based on such an understanding, the technical solution of the present application can be embodied in the form of a software product, and this computer software product can be stored in a storage medium, such as read-only memory (ROM) / RAM, magnetic disk, optical disk, etc., including several instructions for causing a computer device (which can be a personal computer, a server, or a network communication device such as a router) to execute the methods described in each embodiment or some parts of the embodiments of the present application.

[0148] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and for the relevant parts, reference can be made to the partial description of the method embodiments. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0149] The above is only an exemplary embodiment of the present application and is not used to limit the protection scope of the present application.

Claims

1. A control method for caustic soda production, characterized in that, it includes: When the first production data meets the preset production start-up conditions, brine is prepared; When the concentration of the brine reaches the preset concentration, a load increase linkage control is performed on the electrolytic cell, chlorine compressor, and hydrogen compressor; the electrolytic cell is used to electrolyze the brine to obtain sodium hydroxide, hydrogen, and chlorine, the chlorine compressor is used to liquefy chlorine, and the hydrogen compressor is used to process hydrogen; When the hydrogen purity and chlorine purity reach the preset purity, hydrochloric acid is synthesized using hydrogen and chlorine.

2. The method according to claim 1, characterized in that, The load increase linkage control of the electrolytic cell, chlorine compressor, and hydrogen compressor includes: Controlling the electrolytic current of the electrolytic cell to rise to the first target current and controlling the production parameters of the electrolytic cell; Using the chlorine compressor reflux double regulating valve in the chlorine compressor to dynamically adjust the internal pressure of the chlorine compressor according to the chlorine inlet pressure of the chlorine compressor and dynamically adjust the chlorine temperature according to the chlorine outlet pressure of the chlorine compressor; Controlling the load currents of at least two of the hydrogen compressors to be the same and dynamically adjusting the internal pressure and liquid phase liquid level height of the hydrogen compressor.

3. The method according to claim 2, characterized in that, The controlling the production parameters of the electrolytic cell includes: Increasing the flow rate of the brine flowing into the electrolytic cell according to the electrolytic current; increasing the flow rate of hydrochloric acid added to the brine according to the electrolytic current; increasing the flow rate of pure water added for alkali concentration according to the electrolytic current; increasing the steam temperature in the electrolytic cell according to the electrolytic current; controlling the chlorine-hydrogen pressure difference according to the electrolytic current; controlling the flow rate into the resin tower according to the brine liquid level.

4. The method according to claim 1, characterized in that, When stopping the production of caustic soda, the method further includes: When the second production data meets the preset production stop conditions, a load decrease linkage control is performed on the electrolytic cell, the chlorine compressor, and the hydrogen compressor; Controlling nitrogen to be filled into the anode and cathode tank heads of the electrolytic cell and stopping the synthesis of hydrochloric acid; When the electrolytic current drops to 0, controlling the chlorine compressor and the hydrogen compressor to stop working; Controlling the electrolytic cell to replace chloride ions, and when the chloride ion concentration reaches the preset concentration, controlling the electrolytic cell to stop working; Stopping the preparation of brine.

5. The method according to claim 4, characterized in that, The load decrease linkage control of the electrolytic cell, the chlorine compressor, and the hydrogen compressor includes: Controlling the electrolytic current of the electrolytic cell to decrease to the second target current and controlling the production parameters of the electrolytic cell; Using the chlorine compressor reflux double regulating valve in the chlorine compressor to dynamically adjust the internal pressure of the chlorine compressor according to the chlorine inlet pressure of the chlorine compressor and dynamically adjust the chlorine temperature according to the chlorine outlet pressure of the chlorine compressor; Controlling the load currents of at least two of the hydrogen compressors to be the same and dynamically adjusting the internal pressure and liquid phase liquid level height of the hydrogen compressor.

6. The method according to claim 5, characterized in that, The controlling the production parameters of the electrolytic cell includes: Reduce the flow rate of the brine flowing into the electrolytic cell according to the electrolysis current; reduce the flow rate of hydrochloric acid added to the brine according to the electrolysis current; reduce the flow rate of pure water added to adjust the alkali concentration according to the electrolysis current; reduce the steam temperature in the electrolytic cell according to the electrolysis current; control the chlorine-hydrogen pressure difference according to the electrolysis current; control the flow rate into the resin tower according to the brine level.

7. A control device for caustic soda production, characterized in that, it includes: A brine preparation module for preparing brine when the first production data meets the preset production start conditions; A linkage control module for performing a load increase linkage control on the electrolytic cell, chlorine compressor, and hydrogen compressor when the concentration of the brine reaches a preset concentration; the electrolytic cell is used for electrolyzing the brine to obtain sodium hydroxide, hydrogen, and chlorine, the chlorine compressor is used for liquefying chlorine, and the hydrogen compressor is used for processing hydrogen; A hydrochloric acid synthesis module for synthesizing hydrochloric acid using hydrogen and chlorine when the purities of hydrogen and chlorine reach preset purities.

8. The device according to claim 7, characterized in that, The linkage control module is specifically used for: Controlling the electrolysis current of the electrolytic cell to rise to a first target current and controlling the production parameters of the electrolytic cell; Dynamically adjusting the internal pressure of the chlorine compressor according to the chlorine inlet pressure of the chlorine compressor and dynamically adjusting the chlorine temperature according to the chlorine outlet pressure of the chlorine compressor by using the chlorine compressor reflux double regulating valve in the chlorine compressor; Controlling the load currents of at least two of the hydrogen compressors to be the same and dynamically adjusting the internal pressure and the liquid phase level height of the hydrogen compressor.

9. A computer device, characterized in that, it includes: A memory, a processor, and a computer program stored on the memory and executable on the processor, and when the processor executes the computer program, it implements the control method for caustic soda production according to any one of claims 1-6.

10. A computer storage medium, characterized in that, Instructions are stored in the computer storage medium, and when the instructions are run on a terminal device, the terminal device is caused to execute the control method for caustic soda production according to any one of claims 1-6.

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