Automatic control system for preparing manganous-manganic oxide from impurity-containing manganese liquid and use method of automatic control system

Abstract

The invention provides a control system for preparing manganous-manganic oxide from impurity-containing manganese liquid. Comprising a synthesis kettle; the feeding metering pump set comprises a liquid caustic soda metering pump and a pre-synthesis liquid metering pump; the valve group comprises a discharge valve, a steam valve and a pure water valve; the pH meter is arranged on the synthesis kettle; a first flow meter; a second flow meter; the M01 stirring motor is arranged on the synthesis kettle and is used for mixing solutions in the kettle; the M02 stirring motor is arranged on the overflow liquid receiving tank; the air blower is arranged on a pipeline connected with the synthesis kettle; the first liquid level meter is arranged on the synthesis kettle; the second liquid level meter is arranged on the overflow liquid receiving tank; and the thermometer is arranged on the synthesis kettle and is used for monitoring the temperature of the solution in the synthesis kettle. The system further comprises a central controller. By means of the system, the feeding state of the synthesis kettle can be automatically regulated and controlled, monitoring, debugging and alarming of the preparation process are facilitated, meanwhile, feeding of feeding liquid is stable, the temperature of the synthesis kettle is accurately controlled, and the fluctuation range of the pH value is small.

Description

Technical Field

[0001] The invention belongs to the technical field of automatic control, and in particular relates to an automatic control system for preparing manganese tetraoxide from impure manganese-containing liquid and a use method thereof. Background Art

[0002] Synthesis is the most important step in the process of preparing manganese oxide from impure manganese liquid. The stability of the feed and synthesis system determines the quality of manganese oxide, which in turn is greatly related to the various electrochemical properties of the finished battery and the safety of the battery equipment.

[0003] At present, the synthesis process of preparing manganese oxide from impure manganese liquid is still under manual intervention and control. The feed, valve, flow, pH and temperature in the synthesis process have not formed interlocking control, and standardized products have not yet been formed, which is not conducive to the output and production organization and management of high-quality manganese oxide.

[0004] The most important process parameter in the preparation of manganese tetraoxide from impure manganese liquid is the pH control of the synthesis kettle. The pH value of the synthesis kettle is a key parameter for the production of high-end products and is a large hysteresis link. Traditional pH control uses a single-loop PID control method, but due to the nonlinearity and hysteresis of pH measurement, it is easy to cause system response overshoot or oscillation during the control process. It is difficult to achieve fast and accurate control in actual application, resulting in a high scrap rate.

[0005] In addition, the manually controlled production mode lacks centralized alarm warnings, and inadequate inspections by on-site personnel can easily cause chain shutdowns of equipment, leading to production accidents and affecting production. Summary of the invention

[0006] In order to solve the above technical problems, the purpose of the present invention is to provide an automatic control system for preparing manganese tetraoxide using manganese-containing liquid produced by nickel-cobalt hydrometallurgy as raw material and a method for using the same. The system can quickly realize accurate control of the pH value of the solution in the synthesis kettle. The system has a high degree of automation, a standardized process, and can effectively improve the quality of manganese tetraoxide.

[0007] The present invention provides an automatic control system for preparing manganese tetraoxide, comprising: The feed metering pump group comprises a liquid alkali metering pump connected to the synthesis kettle and a pre-synthesis liquid metering pump connected to the synthesis kettle. The output end of the feed metering pump group is connected to the synthesis kettle.

[0008] A valve group, including a discharge valve arranged at the bottom of the synthesis reactor, a steam valve arranged on the pipeline connecting the steam main pipe and the synthesis reactor, and a valve arranged on the pipeline connecting the pure water main pipe and the synthesis reactor; An overflow liquid receiving tank, wherein the overflow liquid receiving tank is connected to the overflow port of the synthesis reactor; A pH meter, arranged on the synthesis reactor, for monitoring the pH value of the solution in the synthesis reactor; The flow meter comprises a first flow meter and a second flow meter, wherein the first flow meter is arranged on the pipeline between the liquid alkali metering pump and the synthesis reactor; the second flow meter is arranged on the pipeline between the pre-synthesis liquid metering pump and the synthesis reactor; The stirring motors, including the M01 stirring motor and the M02 stirring motor, are arranged on the synthesis reactor and are used for mixing the solution in the reactor; the M02 stirring motor is arranged on the overflow receiving tank and is used for mixing the solution in the tank; A blower, arranged on a pipeline connected to the synthesis reactor, for filling the reactor with air; The liquid level meter comprises a first liquid level meter and a second liquid level meter, wherein the first liquid level meter is arranged on the synthesis reactor and is used to monitor the height of the solution in the synthesis reactor; the second liquid level meter is arranged on the overflow receiving tank and is used to monitor the height of the solution in the overflow receiving tank; A thermometer, arranged on the synthesis reactor, for monitoring the temperature of the solution in the synthesis reactor; The central controller is electrically connected to the feed metering pump group, valve group, pH meter, flow meter, stirring motor, blower, liquid level meter, and thermometer; wherein, The central controller uses a cascade control method to adjust the pump speed of the liquid alkali metering pump according to the feedback values ​​of the first flow meter and the pH meter to adjust the addition amount of the liquid alkali.

[0009] The central controller uses a single-loop PID control method to adjust the pump speed of the pre-synthesis liquid metering pump according to the feedback value of the second flow meter to adjust the addition amount of the pre-synthesis liquid.

[0010] The central controller uses a single-loop PID control method to adjust the opening of the steam valve according to the feedback value of the thermometer to adjust the amount of steam introduced; A further preferred embodiment further comprises: An overflow liquid receiving tank is connected to the upper overflow pipe of the synthesis reactor to collect overflowed solution.

[0011] A further preferred solution is that the liquid level meter is a radar liquid level meter arranged on the top of the synthesis reactor and the overflow liquid receiving tank.

[0012] A further preferred solution is that the flow meter is an electromagnetic flow meter.

[0013] A further preferred solution is that a parameter alarm program is provided in the central controller.

[0014] A further preferred solution is that a device group start-stop interlock is also provided in the central controller.

[0015] Another aspect of the present invention provides a method for using an automatic control system for preparing manganese tetraoxide from a manganese-containing liquid, which is implemented using the automatic control system for preparing manganese tetraoxide from a manganese-containing liquid as described above, comprising the following steps: S1. According to the preset program of the central controller, the liquid alkali metering pump and the pre-synthesis liquid metering pump are started and the valves of the pure water pipeline and the steam pipeline are opened to allow the liquid alkali, pre-synthesis liquid, pure water and steam to enter the synthesis reactor. At the same time, the pH meter, flow meter, liquid level meter, thermometer and stirring motor are started.

[0016] S2. The pH meter monitors the pH value of the solution in the synthesis kettle, the flow meter monitors the flow rate of the liquid in the pipeline, the liquid level meter monitors the height of the liquid in the synthesis kettle, and the thermometer monitors the liquid temperature in the synthesis kettle. The monitoring data of the pH meter, flow meter, liquid level meter and thermometer are uploaded to the central controller.

[0017] S3. The central controller adjusts the pump speed of its metering pump according to the flow rate of liquid alkali to adjust the amount of liquid alkali added. The central controller adjusts the pump speed of its metering pump according to the flow rate of pre-synthesis liquid to adjust the amount of pre-synthesis liquid added. The central controller adjusts the opening of the steam valve according to the temperature of the solution in the synthesis reactor to adjust the amount of steam introduced. The central controller also adjusts the pump speed of the metering pump for conveying liquid alkali according to the pH value of the pH meter to adjust the amount of liquid alkali added.

[0018] S4. When the pH value and temperature of the solution in the synthesis reactor are stable within the preset range of the central controller, the particle size of the manganese tetraoxide is manually and regularly detected. When the particle size is qualified, the machine is shut down with one button, and the central controller stops the metering pump, the mixer, and the pure water pipeline valve and the steam pipeline valve; after the shutdown, the discharge valve is opened, and the synthesis reactor is emptied and restarted.

[0019] A further preferred scheme is that the liquid alkali adopts a cascade control method, the secondary loop adopts a proportional control method to adjust the outlet flow rate of the liquid alkali feed pump to control the amount of liquid alkali added, and the main loop adopts a PID control method to adjust the pH value of the solution in the synthesis reactor.

[0020] According to the above content, the automatic control system for preparing manganese tetraoxide with impurity-containing manganese liquid of the present invention can obtain the flow rate of the feed liquid, the temperature and pH value in the synthesis reactor through the central controller, and can adjust the addition amount of the feed liquid by setting the central controller, so that the pH value in the synthesis reactor fluctuates less and the range of regulation is more accurate, thereby improving the quality of manganese tetraoxide. In addition, the use method of the automatic control system for preparing manganese tetraoxide with impurity-containing manganese liquid of the present invention can make the above control system automatically run according to the preset method, which is convenient for the unified management of the system and ensures the stability of manganese tetraoxide during synthesis.

[0021] In order to achieve the above and related purposes, one or more aspects of the present invention include features that will be described in detail later and are particularly pointed out in the claims. The following description and the accompanying drawings describe some exemplary aspects of the present invention in detail. However, these aspects indicate only some of the various ways in which the principles of the present invention can be used. In addition, the present invention is intended to include all of these aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The structure diagram of the automatic control system for preparing manganese tetraoxide from impure manganese liquid; Figure 2 The schematic diagram of pH value control of the automatic control system for preparing manganese tetraoxide from impure manganese liquid; Figure 3 A flow chart of the method for using the automatic control system for preparing manganese tetraoxide from impure manganese liquid; Description of reference numerals: 1-liquid alkali metering pump; 2-pre-synthesis liquid metering pump; 3-first flow meter; 4-second flow meter; 5-first liquid level meter; 6-second liquid level meter; 7-pH meter; 8-thermometer; 9-M01 stirring motor; 10-M02 stirring motor; 11-central controller; 12-steam valve; 13-pure water valve; 14-blower; 15-synthesis kettle; 16-discharge valve; 17-overflow liquid receiving tank. DETAILED DESCRIPTION

[0023] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0024] Unless otherwise defined, all professional terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or can be obtained by existing methods.

[0025] like Figure 1 As shown, the automatic control system for preparing manganese tetraoxide from impurity-containing manganese liquid of the present invention includes a metering pump group, a flow meter, a pH meter, a valve group, a thermometer, a synthesis kettle, an overflow tank and a central controller.

[0026] The metering pump group comprises a liquid caustic soda metering pump 1 connected to the liquid caustic soda and a pre-synthesis liquid metering pump 2 connected to the pre-synthesis liquid. The output end of the metering pump group is connected to the synthesis kettle. The pH meter 7 is arranged on the synthesis reactor 15 to monitor the pH value of the solution in the synthesis reactor 15. The first flow meter 3 is arranged on the pipeline between the liquid alkali metering pump 1 and the synthesis reactor 15. The second flow meter 4 is arranged on the pipeline between the pre-synthesis liquid metering pump 2 and the synthesis reactor 15. The first liquid level meter 5 is arranged on the synthesis reactor 15. The second liquid level meter 6 is arranged on the overflow receiving tank 16 connected to the overflow port of the synthesis reactor 15. The thermometer 8 is arranged on the side of the synthesis reactor 15 to monitor the temperature value of the solution in the synthesis reactor 15. The discharge valve 16 is arranged at the bottom of the synthesis reactor 15 to facilitate the discharge of liquid after synthesis. The steam valve 12 is arranged on the pipeline connecting the steam and the synthesis reactor 15. The pure water valve 13 is arranged on the pipeline connecting the pure water main pipe and the synthesis reactor 15. The overflow receiving tank 16 is connected to the overflow port of the synthesis reactor 15 by a pipeline. The blower 14 is arranged on the ventilation pipeline connected to the synthesis reactor 15. The central controller 11 is electrically connected to the flow meter, level meter, valve, pH meter, thermometer, pump group, valve group, etc., and controls the speed of the feed liquid on the metering pump through the metering pump, thereby controlling the amount of the feed liquid in the synthesis reactor.

[0027] The central controller 11 uses a cascade control method to adjust the pump speed of the liquid alkali metering pump 1 to adjust the amount of liquid alkali added according to the feedback values ​​of the first flow meter 3 and the pH meter 7. The central controller 11 uses a single-loop PID control method to adjust the pump speed of the pre-synthesis liquid metering pump 2 to adjust the amount of pre-synthesis liquid added according to the feedback value of the second flow meter 4. The central controller 11 uses a PID control method to control the steam inlet of the steam valve 12 according to the feedback value of the thermometer 8. The central controller 11 uses a start-stop interlock control method to control the switch state of the pure water valve 13 according to the feedback value of the first liquid level meter 5. The central controller 11 uses a start-stop interlock control method to control the start-stop state of the pre-synthesis liquid metering pump 2 according to the feedback value of the first liquid level meter 5. The central controller 11 is a device with a logic calculation function, capable of running program code, and processing data. In this embodiment, the central controller 11 is a desktop computer with a display screen for users to view relevant data. The central controller 11 controls the start and stop of the metering pump, the central controller 11 controls the start and stop of the stirring motor, and the central controller 11 controls the start and stop of the blower 14. The feed liquid enters the synthesis reactor 15 through the feed pump to complete mixing. During this period, the flow meter, liquid level meter, pH meter 7 and thermometer 8 display the measured values ​​in real time on the central controller 11.

[0028] In this example, the discharge valve 16 is first opened by the central controller 11 to empty the synthesis reactor 15; after the feedback value of the first liquid level meter 5 is 0, the discharge valve 16 is closed and the pure water valve 13 is opened at the same time.

[0029] When the feedback value of the first liquid level meter 5 reaches 0.3, the pure water valve 13 is interlocked and closed. At the same time, the M01 stirring motor 9 is started through the central controller 11, and the stirring speed of the M01 stirring motor 9 is 145 rpm. The liquid alkali metering pump 1 is started through the central controller 11.

[0030] The pumping speed of the liquid alkali metering pump 1 is adjusted by the feedback value of the first flow meter 3 .

[0031] When the feedback value of the pH meter 7 reaches 9, the central controller 11 starts the pre-synthesis liquid metering pump 2, wherein the pumping speed of the pre-synthesis liquid metering pump 2 is adjusted by the feedback value of the second flow meter 4, and the blower 14 is turned on at the same time, wherein the air volume of the blower 14 is 120m 3 / h.

[0032] Set the flow rate of the second flow meter 4 to 0.6m 3 / h, and the pump speed of the pre-synthesis liquid metering pump 2 is controlled by PID. The pH value is stabilized at 8-9, and the feedback value of the first flow meter 3 is adjusted by the central controller 11, thereby controlling the pump speed of the liquid caustic soda metering pump to adjust the amount of liquid caustic soda added.

[0033] On the basis of stable addition of pre-synthesis liquid, the pH value in the synthesis reactor 15 is stabilized by controlling the amount of liquid caustic soda added. However, due to the nonlinearity and hysteresis of the pH value, it often causes overshoot or oscillation of the system response during the control process. Therefore, the addition of liquid caustic soda adopts a cascade PID adjustment method.

[0034] like Figure 2 As shown, the secondary loop adopts flow control at the outlet of the feed pump of liquid caustic soda, and the main loop adopts pH control in the synthesis reactor 15. Among them, the secondary loop adopts proportional control (P control: control that the output and input are linearly proportional), and the outlet flow of the feed pump of liquid caustic soda is adjusted to control the amount of liquid caustic soda added, which can quickly and timely eliminate the internal interference of the secondary loop (interference includes disturbances in the regulating loop of the flow of liquid caustic soda, changes in the amount of liquid caustic soda added, and other possible sources including equipment vibration, unstable back pressure at the pump outlet and other disturbance factors), playing a "rough adjustment" role. The secondary loop of the cascade PID loop immediately enters the adjustment, which can quickly and timely eliminate the internal interference of the secondary loop, and after adjustment, it will basically not affect the pH value in the synthesis reactor 7.

[0035] The control screen of the central controller system can display the operating status of each metering pump and valve, as well as the data display of each liquid level meter, thermometer, and pH meter, and has important parameter deviation alarm functions, such as pH deviation alarm, temperature deviation alarm, and deviation alarm of liquid alkali addition, and local control function of pump group start and stop. It also includes PID parameter setting, historical data query, and drawing of historical data trend curves. At the same time, equipment group start and stop interlocking and parameter alarm procedures are also set to effectively ensure the accurate and stable operation of the automatic control system for preparing manganese tetraoxide from impure manganese liquid.

[0036] like Figure 3 The present invention shows the process of using the automatic control system for preparing manganese tetraoxide from manganese-containing liquid.

[0037] like Figure 3 As shown, a method for using an automatic control system for preparing manganese tetraoxide from a manganese-containing liquid is provided.

[0038] The automatic control system for preparing manganese tetraoxide using the impurity-containing manganese liquid as described above is implemented, comprising the following steps: S1. According to the preset program of the central controller, the liquid alkali metering pump and the pre-synthesis liquid metering pump are started and the valves of the pure water pipeline and the steam pipeline are opened to allow the liquid alkali, pre-synthesis liquid, pure water and steam to enter the synthesis reactor. At the same time, the pH meter, flow meter, liquid level meter, thermometer and stirring motor are started.

[0039] S2. The pH meter monitors the pH value of the solution in the synthesis kettle, the flow meter monitors the flow rate of the liquid in the pipeline, the liquid level meter monitors the height of the liquid in the synthesis kettle, and the thermometer monitors the liquid temperature in the synthesis kettle. The monitoring data of the pH meter, flow meter, liquid level meter and thermometer are uploaded to the central controller.

[0040] S3. The central controller adjusts the pump speed of its metering pump according to the flow rate of liquid alkali to adjust the amount of liquid alkali added. The central controller adjusts the pump speed of its metering pump according to the flow rate of pre-synthesis liquid to adjust the amount of pre-synthesis liquid added. The central controller adjusts the opening of the steam valve according to the temperature of the solution in the synthesis reactor to adjust the amount of steam introduced. The central controller also adjusts the pump speed of the metering pump for conveying liquid alkali according to the pH value of the pH meter to adjust the amount of liquid alkali added.

[0041] S4. When the pH value and temperature of the solution in the synthesis reactor are stable within the preset range of the central controller, the particle size of the manganese tetraoxide is manually and regularly detected. When the particle size is qualified, the machine is shut down with one button, and the central controller stops the metering pump, the mixer, and the pure water pipeline valve and the steam pipeline valve; after the shutdown, the discharge valve is opened, and the synthesis reactor is emptied and restarted.

[0042] A further preferred solution is that the liquid alkali adopts a cascade control method, loop one adopts a proportional control method to adjust the outlet flow rate of the liquid alkali feed pump to control the amount of liquid alkali added, and loop two adopts a PID control method to adjust the pH value of the solution in the synthesis reactor.

[0043] Furthermore, when an accident or emergency occurs, the liquid in the synthesis reactor 15 can overflow into the overflow receiving tank 17 through the overflow pipe to reduce material loss.

[0044] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An automatic control system for preparing manganese tetraoxide from impure manganese liquid, characterized in that: include: Reactor; A feed metering pump group, comprising a liquid alkali metering pump and a pre-synthesis liquid metering pump connected to the synthesis reactor, wherein the output end of the feed metering pump group is connected to the synthesis reactor; A valve group, including a discharge valve arranged at the bottom of the synthesis reactor, a steam valve arranged on the pipeline connecting the steam main pipe and the synthesis reactor, and a pure water valve arranged on the pipeline connecting the pure water main pipe and the synthesis reactor; A pH meter, arranged on the synthesis reactor, for monitoring the pH value of the solution in the synthesis reactor; The flow meter comprises a first flow meter and a second flow meter, wherein the first flow meter is arranged on the pipeline between the liquid alkali metering pump and the synthesis reactor; the second flow meter is arranged on the pipeline between the pre-synthesis liquid metering pump and the synthesis reactor; M01 stirring motor, arranged on the synthesis reactor, used for mixing the solution in the reactor; A blower, arranged on a pipeline connected to the synthesis reactor, for filling the reactor with air; A first liquid level meter, provided on the synthesis reactor, for monitoring the height of the solution in the synthesis reactor; A thermometer, arranged on the synthesis reactor, for monitoring the temperature of the solution in the synthesis reactor; The central controller is electrically connected with the feed metering pump group, the valve group, the pH meter, the first flow meter, the second flow meter, the M01 stirring motor, the blower, the first liquid level meter, and the thermometer.

2. The automatic control system for preparing manganese tetraoxide from impure manganese liquid according to claim 1, characterized in that: The automatic control system also includes: An overflow liquid receiving tank, the overflow liquid receiving tank is connected to the overflow port of the synthesis reactor to collect the overflowed solution; M02 stirring motor, arranged on the overflow liquid receiving tank, used for mixing the solution in the tank; A second liquid level meter, provided on the overflow receiving tank, for monitoring the height of the solution in the overflow receiving tank; The M02 stirring motor and the second liquid level meter are electrically connected to the central controller respectively.

3. The automatic control system for preparing manganese manganese tetroxide from impure manganese liquid according to claim 2, characterized in that: The central controller uses a cascade control method to adjust the pump speed of the liquid alkali metering pump according to the feedback values ​​of the first flow meter and the pH meter to adjust the addition amount of the alkali solution; The central controller uses a single-loop PID control method to adjust the pump speed of the pre-synthesis liquid metering pump according to the feedback value of the second flow meter to adjust the addition amount of the pre-synthesis liquid; The central controller uses a single-loop PID control method to adjust the opening of the steam valve according to the feedback value of the thermometer to adjust the amount of steam introduced.

4. The automatic control system for preparing manganese manganese tetroxide from impure manganese liquid as claimed in claim 2, characterized in that: A parameter alarm program is arranged in the central controller.

5. The automatic control system for preparing manganese manganese tetroxide from impure manganese liquid as claimed in claim 2, characterized in that: The central controller is also provided with a device group start-stop interlock.

6. A method for using an automatic control system for preparing manganese tetraoxide from a manganese-containing liquid, which is implemented using the automatic control system for preparing manganese tetraoxide from a manganese-containing liquid as described in any one of claims 2 to 5, characterized in that: The following steps are involved: S1. According to the preset program of the central controller, the liquid alkali metering pump and the pre-synthesis liquid metering pump are started and the pure water valve of the pure water pipeline and the steam valve of the steam pipeline are opened to allow the liquid alkali, pre-synthesis liquid, pure water and steam to enter the synthesis reactor, and at the same time, the pH meter, flow meter, first liquid level meter, thermometer, M01 stirring motor and M02 stirring motor are started; S2, a pH meter monitors the pH value of the solution in the synthesis kettle, a flow meter monitors the flow rate of the liquid in the pipeline, a first liquid level meter monitors the height of the liquid in the synthesis kettle, and a thermometer monitors the temperature of the liquid in the synthesis kettle. The monitoring data of the pH meter, the flow meter, the first liquid level meter and the thermometer are uploaded to the central controller; S3, the central controller adjusts the pump speed of its metering pump according to the flow rate of liquid caustic soda to adjust the amount of liquid caustic soda added, the central controller adjusts the pump speed of its metering pump according to the flow rate of pre-synthesis liquid to adjust the amount of pre-synthesis liquid added, the central controller adjusts the opening of the steam valve according to the temperature of the solution in the synthesis reactor to adjust the amount of steam introduced, and the central controller also adjusts the pump speed of the metering pump for conveying liquid caustic soda according to the acid-base value of the pH meter to adjust the amount of liquid caustic soda added; S4. When the pH value and temperature of the solution in the synthesis reactor are stable within the preset range of the central controller, the particle size of the manganese tetraoxide is manually and regularly detected. When the particle size is qualified, the machine is shut down with one button, and the central controller stops the metering pump, the mixer, and the pure water pipeline valve and the steam pipeline valve; after the shutdown, the discharge valve is opened, and the synthesis reactor is emptied and restarted.

7. The method for using the automatic control system for preparing manganese tetraoxide from impure manganese liquid as claimed in claim 6, characterized in that: When encountering an accident or emergency, the liquid in the synthesis reactor can overflow into the overflow receiving tank through the overflow pipe to reduce material loss.

8. The method for using the automatic control system for preparing manganese tetraoxide from impure manganese liquid as claimed in claim 6, characterized in that: The liquid alkali adopts the cascade control method, the secondary loop adopts the proportional control method to adjust the outlet flow of the liquid alkali feed pump to control the amount of liquid alkali added, and the main loop adopts the PID control method to adjust the pH value of the solution in the synthesis kettle.

Images