Device and method for enabling lime milk preparation system to operate stably

Abstract

The invention belongs to the technical field of steelmaking wastewater treatment, and particularly relates to a device and a method for enabling a lime milk preparation system to operate stably, in the device, a radar level gage is installed in the middle of the top of a calcium hydroxide powder bin, and a high-resistance rotation level gage and a low-resistance rotation level gage are both installed outside the side wall of a cylinder of the calcium hydroxide powder bin; the low-frequency oscillators are symmetrically installed on the two sides of a cone of the calcium hydroxide powder bin, the lower portion of the cone is connected with the pipeline, the manual insertion plate door, the upper electric insertion plate door, the star-shaped feeder, the spiral conveyor and the lower electric insertion plate door are sequentially connected to the pipeline, and the lower electric insertion plate door is connected into the lime milk dissolving box through the pipeline. The method comprises the following steps of multi-stage material level redundancy detection, low-frequency oscillator-star feeder-screw conveyor three-stage collaborative blanking, star feeder frequency conversion and screw conveyor closed-loop metering, and safety isolation of an upper electric plug plate door and a lower electric plug plate door. According to the device and method, accurate discharging is achieved, calcium hydroxide hardening in the system is prevented, and the system operates safely and stably.

Description

Technical Field

[0001] This invention belongs to the field of steelmaking wastewater treatment technology, and particularly relates to an apparatus and method for stabilizing the operation of a lime slurry preparation system. Background Technology

[0002] The steelmaking waste acid water neutralization and treatment system uses lime slurry solution for neutralization and precipitation. The pH of the waste acid water is neutralized from 1 to 7 before being reused as slag. A lime slurry solution of approximately 10% (corresponding density of 1080 kg / m³) is prepared from Ca(OH)₂ powder processed with industrial water. 3 The process flow of the lime slurry preparation system is as follows: Calcium hydroxide powder is pneumatically conveyed from a tanker truck to the Ca(OH)2 powder silo. Then, lime slurry solution is prepared in a dissolving tank. The prepared slurry is stored in a lime slurry storage tank, and then pumped by a lime slurry transfer pump to a triplet tank for neutralization with waste acid. The following problems are prone to occur during actual operation: (1) The powder silo level detection relies on a single rotary paddle or radar level gauge, which is subject to dust interference. Due to the strong hygroscopicity of calcium hydroxide, the rotating blades inside the rotary paddle level switch are prone to adsorbing caking calcium hydroxide during actual operation, which causes false alarms due to material adhering to the wall. Moreover, the machine needs to be stopped during maintenance, which affects the continuous operation of the lime milk preparation system. (2) The feeding device mostly uses a single screw conveyor or vibrating feeder. Because calcium hydroxide powder is highly hygroscopic, it becomes sticky after getting damp. The inner wall of the powder silo cone is prone to caking and blockage, resulting in large fluctuations in the addition of calcium hydroxide powder and a density deviation of more than ±5% in lime slurry. Feeding is interrupted, and lime slurry preparation is unstable. (3) The metering system consists of a manual gate and a feeder. During the powder silo feeding process, due to the entry of outside air or the return of moisture from the dissolving box, caking occurs in the feeder, the feeding amount cannot be accurately controlled, and the lime milk ratio is unstable. (4) Insufficient safety protection, external moisture backflow causes powder caking at the outlet of the silo, and the material cannot be quickly isolated during fault repair, resulting in a long system recovery time; the feeder and screw conveyor have no coordinated feedback, and the flow rate cannot be corrected in real time. Summary of the Invention

[0003] The purpose of this invention is to provide an apparatus and method for stabilizing the operation of a lime slurry preparation system, thereby addressing the shortcomings in the aforementioned background technology.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A device for stabilizing the operation of a lime slurry preparation system includes a calcium hydroxide powder storage and metering system and a calcium hydroxide powder feeding and weighing system. The calcium hydroxide powder storage and metering system includes a calcium hydroxide powder silo, a radar level gauge, a high-resistance vortex level gauge, and a low-resistance vortex level gauge. The upper part of the calcium hydroxide powder silo is cylindrical, and the lower part is conical. The radar level gauge is installed at the top center of the calcium hydroxide powder silo. The high-resistance vortex level gauge and the low-resistance vortex level gauge are both installed on the outer side wall of the cylindrical part of the calcium hydroxide powder silo and arranged vertically on the same side. The calcium hydroxide powder feeding and weighing system includes two low-frequency oscillators, a manual gate, an upper electric gate, a star feeder, a screw conveyor, and a lower electric gate. The low-frequency oscillator is symmetrically installed on both sides of the cone of the calcium hydroxide powder silo, located at the upper expansion joint of the cone. The lower part of the cone is connected to the pipeline. The pipeline is sequentially connected to a manual slide gate, an upper electric slide gate, a star feeder, a screw conveyor, and a lower electric slide gate. The manual slide gate, upper electric slide gate, star feeder, screw conveyor, lower electric slide gate, and pipeline are connected by flanges. The oscillator, star feeder, and screw conveyor work together in a closed loop to discharge materials. The lower electric slide gate is connected to the lime slurry dissolving tank through the pipeline. The radar level gauge, high-resistance rotary level gauge, low-resistance rotary level gauge, low-frequency oscillator, upper electric slide gate, star feeder, screw conveyor, and lower electric slide gate are all connected to the shutdown safety protection interlock logic control system.

[0005] Preferably, the high-resistance vortex level gauge is arranged 1 meter away from the top of the calcium hydroxide powder silo, and the low-resistance vortex level gauge is arranged 0.5 meters away from the top of the cone of the calcium hydroxide powder silo. The two vortex level gauges are of the same specification.

[0006] Preferably, the motor of the star feeder is a variable frequency motor, and the screw conveyor is equipped with automatic weighing and metering.

[0007] Preferably, the two low-frequency oscillators are started and stopped simultaneously. When the system is started, it oscillates once every 10 minutes for 20 seconds. When the system is stopped, it oscillates once every 60 minutes for 10 seconds to prevent excessive vibration and compaction of materials when the system is stopped.

[0008] A method for stabilizing the operation of a lime slurry preparation system includes the following: (1) Multi-level redundant material level detection: cross-validation of data from high-resistance rotary level gauge, low-resistance rotary level gauge and radar level gauge. Automatic switching of main control signal source when any equipment fails, to ensure uninterrupted operation of material level monitoring and lime slurry preparation; (2) Three-stage coordinated feeding of low frequency oscillator-star feeder-screw conveyor: The vibration frequency of the low frequency oscillator is linked with the material level of the calcium hydroxide powder silo. When the material level is higher than 50%, the vibration duration of the low frequency oscillator is set to 10-15S, and it vibrates once every 30-40 minutes. When the material level is lower than 50%, the vibration duration of the low frequency oscillator is set to 15-20S, and it vibrates once every 15-20 minutes. During operation, the oscillation cycle is dynamically adjusted according to the material level change and the feeding amount of the screw conveyor by PID. The speed of the star feeder motor is dynamically adjusted according to the feeding speed of the screw conveyor to prevent the bolt conveyor from being blocked by the excessively fast feeding. This achieves the following: the low frequency oscillator breaks up the powder arching, the star feeder quantitatively intercepts and prevents blockage, and the screw conveyor steadily conveys the powder. (3) Closed-loop metering of variable frequency star feeder + screw conveyor: Feedforward control: The star feeder is set to an initial speed of 15-20 Hz (coarse adjustment) according to the preset flow rate. Feedback control: The screw conveyor weighing module measures the actual flow rate in real time, and the PLC dynamically corrects the frequency of the star feeder (fine-tuning) to ensure uniform and stable feeding and ensure that the density deviation of lime slurry is ≤±1%; (4) Safety isolation between the upper and lower electric sliding door: When any equipment in the feeding system malfunctions and the powder hopper outlet needs to be shut off urgently, the upper electric slide gate will close, with a response time of ≤20 seconds. During shutdown or maintenance, the lower electric gate is closed to block the backflow of moisture in the lime slurry dissolving box, prevent the screw conveyor and star feeder from becoming damp and hardened, and prevent overload damage to the motor or fluctuations in the amount of calcium hydroxide powder added during restart. When shutting down, the response time of the lower electric gate closing is ≤20 seconds to prevent external moisture from entering or to quickly cut off the powder hopper discharge. (5) Interlocking protection shutdown logic of the feeding system: Electric sliding door: When the weighing and metering of the screw conveyor reaches the cumulative design value, the protection will stop. The cumulative design value can be set automatically according to the volume and concentration of the dissolving tank. Star feeder: When the weighing and metering of the screw conveyor reaches the cumulative design value, the protection will stop after 60 seconds; Screw conveyor: When the weighing value of the screw conveyor reaches the cumulative design value, the protection will stop after 120 seconds. Electric slide gate: When the weighing and metering of the screw conveyor reaches the cumulative design value, the protection will stop after 120 seconds. The valves of the feeding system are protected by a delayed closing mechanism to ensure that no calcium hydroxide powder accumulates in the star feeder, screw conveyor, and pipelines during shutdown. This prevents caking caused by prolonged shutdown, which could affect the accuracy of lime slurry preparation and the safety of the equipment during the next startup.

[0009] Preferably, it also includes a method for starting the feeding system, the specific steps of which are as follows: When the system receives the feeding signal, it first opens the lower electric slide gate. When the electric slide gate is fully open, the screw conveyor is started. After running for 15-20 seconds, the star feeder is started. The initial frequency of the star feeder is 15-20 Hz. After running for 15-20 seconds, the upper electric slide gate is started, and the system begins feeding. During the feeding process, the system dynamically corrects the frequency of the star feeder (fine-tuning) according to the feeding speed of the screw conveyor, ensuring uniform and stable feeding and ensuring that the density deviation of lime slurry is ≤±1%. When the feeding system starts, the low-frequency oscillator is dynamically adjusted by PID according to the powder silo level and the feeding amount of the screw conveyor.

[0010] Preferably, the method for shutting down the feeding system also includes the following steps: When the system receives a stop feeding signal, it first closes the upper electric slide gate, then stops the star feeder after 60-70 seconds, and then stops the screw conveyor and the lower electric slide gate after 120-130 seconds. This ensures that after the system stops, the material in the star feeder, screw conveyor and pipeline is completely discharged, preventing compaction and caking due to prolonged shutdown.

[0011] Working principle: Utilizing redundant real-time detection by high-resistance swirl level gauges, low-resistance swirl level gauges, and radar level gauges, the lime slurry preparation system interlocks with radar level gauge data. If radar level gauge data shows abnormalities exceeding a set time, the swirl level gauge automatically selects as the primary signal, interlocking for continuous and normal slurry preparation. Two low-frequency oscillators start and stop simultaneously during system startup or shutdown, vibrating according to a set cycle to prevent excessive material vibration and compaction during shutdown. Electric gates are installed in front of the star feeder and behind the screw conveyor. During shutdown, the lower electric gate closes to prevent external moisture from flowing back into the feeding system, causing damage to the star feeder. If caking and blockage occur inside the feeder and screw conveyor piping, the upper electric gate will close to prevent caking material in the powder silo from entering the star feeder and causing blockage. The star feeder and screw conveyor are subject to closed-loop metering regulation to improve feeding accuracy and stability. When the shutdown safety protection interlock logic control system receives a shutdown signal, it first closes the upper electric gate, then shuts down the star feeder after a set time, and then shuts down the screw conveyor and lower electric gate after another set time. This ensures that after shutdown, the material in the star feeder, screw conveyor, and piping is completely discharged, preventing compaction and caking due to prolonged shutdown.

[0012] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: (1) A combination of high-resistance swirl level gauge, low-resistance swirl level gauge and radar level gauge is used to improve the metering accuracy of the powder silo and avoid the equipment shutdown caused by empty material or overflow in the powder silo; at the same time, the high-resistance swirl level gauge, low-resistance swirl level gauge and radar level gauge are easy to maintain, simple to operate, and can be maintained and repaired without stopping the machine, so that the lime milk preparation system can operate stably and continuously. (2) A high-efficiency closed-loop metering device with variable frequency control of star feeder and automatic weighing of screw conveyor is adopted to accurately control the feeding amount, control the density fluctuation of lime slurry solution, stabilize lime slurry ratio, and reduce the consumption of calcium hydroxide powder. (3) Use the vibrator to ensure the flowability of the powder, and regularly vibrate to break up the caking of the powder silo wall. The shear force of the star feeder blades can break up the bridging. The screw conveyor can achieve continuous and stable conveying. The three work together to prevent material interruption or blockage due to caking, so as to ensure the stable operation of the lime milk preparation system. (4) The upper electric slide gate and the lower electric slide gate are used for safety isolation, which effectively prevents external moisture from entering the star feeder and prevents moisture from flowing back and caking; (5) This method uses redundant material level monitoring with high resistance vortex level gauge, low resistance vortex level gauge and radar level gauge to ensure that the basic data is not interrupted. It uses low frequency oscillator to vibrate regularly to ensure powder flow. It achieves high precision of material feeding through frequency conversion adjustment of star feeder and real-time metering feedback closed-loop PID control of screw weigher. At the same time, it controls the upper electric slide gate and lower electric slide gate in real time for physical isolation to effectively prevent moisture erosion. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention.

[0014] Explanation of reference numerals in the attached diagram: 1. Calcium hydroxide powder silo; 2. Radar level gauge; 3. High-resistance rotary level gauge; 4. Low-resistance rotary level gauge; 5. Low-frequency oscillator; 6. Manual slide gate; 7. Upper electric slide gate; 8. Rotary feeder; 9. Screw conveyor; 10. Lower electric slide gate; 11. Pipeline; 12. Lime slurry dissolving tank. Detailed Implementation

[0015] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0016] like Figure 1As shown, an apparatus for stabilizing the operation of a lime slurry preparation system includes a calcium hydroxide powder storage and metering system and a calcium hydroxide powder feeding and weighing system. The calcium hydroxide powder storage and metering system includes a calcium hydroxide powder silo 1, a radar level gauge 2, a high-resistance vortex level gauge 3, and a low-resistance vortex level gauge 4. The upper part of the calcium hydroxide powder silo 1 is cylindrical, and the lower part is conical. The radar level gauge 2 is installed at the top center of the calcium hydroxide powder silo 1, and a calcium hydroxide inlet is located on the left side of the top. The high-resistance vortex level gauge 3 and the low-resistance vortex level gauge 4 are both installed on the outer side wall of the cylindrical part of the calcium hydroxide powder silo 1 and are arranged vertically on the same side. The rotary level gauge 3 is positioned 1 meter from the top of the calcium hydroxide powder silo 1, and the low-rotational-resistance level gauge 4 is positioned 0.5 meters from the top of the cone of the calcium hydroxide powder silo 1. Both rotary level gauges are of the same specification. The calcium hydroxide powder feeding and weighing system includes two low-frequency oscillators 5, a manual gate 6, an upper electric gate 7, a star feeder 8, a screw conveyor 9, and a lower electric gate 10. The two low-frequency oscillators 5 are symmetrically installed on both sides of the cone of the calcium hydroxide powder silo 1, located at the upper expansion joint of the cone. The two low-frequency oscillators 5 start and stop simultaneously. When the system starts, it oscillates once every 10 minutes, with a vibration duration of 2... 0 seconds. When the system stops, it oscillates once every 60 minutes for 10 seconds to prevent excessive vibration and compaction of materials during shutdown. The lower part of the cone is connected to pipe 11. The upper part of pipe 11 is sequentially connected to manual slide gate 6, upper electric slide gate 7, rotary feeder 8, screw conveyor 9, and lower electric slide gate 10. Manual slide gate 6, upper electric slide gate 7, rotary feeder 8, screw conveyor 9, lower electric slide gate 10, and pipe 11 are connected by flanges. Vibrator 5, rotary feeder 8, and screw conveyor 9 work together in a closed loop for material feeding. The motor of rotary feeder 8 is a variable frequency motor, and screw conveyor 9... Automatic weighing and metering; the initial frequency of the rotary feeder 8 motor is set to 20Hz, and the feeding speed of the screw conveyor is set to 40kg / min. The system uses a PID algorithm for closed-loop metering regulation, that is, the frequency of the rotary feeder is corrected every 30 seconds for the weighing deviation, with an adjustment range of ±1Hz; the lower electric slide gate 10 is connected to the lime slurry dissolving tank 12 through a pipeline. The radar level gauge 2, high-resistance rotary level gauge 3, low-resistance rotary level gauge 4, low-frequency oscillator 5, upper electric slide gate 7, rotary feeder 8, screw conveyor 9 and lower electric slide gate 10 are all connected to the shutdown safety protection interlock logic control system.

[0017] A method for stabilizing the operation of a lime slurry preparation system includes the following: (1) Multi-level redundant material level detection: The data of high resistance rotary level gauge 3, low resistance rotary level gauge 4 and radar level gauge 2 are cross-verified. When any device fails, the main control signal source is automatically switched to ensure uninterrupted operation of material level monitoring and lime slurry preparation. (2) Three-stage coordinated feeding of low frequency oscillator 5-star feeder 8-screw conveyor 9: The vibration frequency of low frequency oscillator 5 is linked with the material level of calcium hydroxide powder silo 1. When the material level is higher than 50%, the vibration duration of low frequency oscillator 5 is set to 10S, and it vibrates once every 30 minutes. When the material level is lower than 50%, the vibration duration of low frequency oscillator is set to 15S, and it vibrates once every 15 minutes. During operation, the oscillation cycle is dynamically adjusted according to the material level change and the feeding amount of screw conveyor 9 by PID. The motor speed of star feeder 8 is dynamically adjusted according to the feeding speed of screw conveyor 9 to prevent the bolt conveyor from being blocked by excessive feeding. This achieves the following: low frequency oscillator 5 breaks up powder arching, star feeder 8 quantitatively intercepts and prevents blockage, and screw conveyor 9 steadily conveys. (3) Closed-loop metering of star feeder 8 frequency converter + screw conveyor 9: Feedforward control: The initial speed of the star feeder 8 is set to 15-20 Hz (coarse adjustment) according to the preset flow rate. Feedback control: The screw conveyor's 9 weighing modules measure the actual flow rate in real time, and the PLC dynamically corrects the frequency of the star feeder 8 (fine-tuning) to ensure uniform and stable material feeding and ensure that the density deviation of lime slurry is ≤±1%; (4) Safety isolation between the upper and lower electric sliding door: When any equipment in the feeding system malfunctions and the powder hopper outlet needs to be shut off urgently, the upper electric slide gate 7 will close, with a response time of ≤20 seconds; During shutdown or maintenance, the lower electric slide gate 10 is closed to block the backflow of moisture in the lime slurry dissolving tank 12, preventing the screw conveyor 9 and the star feeder 8 from becoming damp and hardened, and preventing overload damage to the motor or fluctuations in the amount of calcium hydroxide powder added during restart. When shut down, the response time of the lower electric slide gate 9 closing is ≤20 seconds to prevent external moisture from entering or to quickly cut off the powder hopper discharge. (5) Interlocking protection shutdown logic of the feeding system: Electric sliding door 7: When the weighing of the screw conveyor 9 reaches the cumulative design value, the protection stops. The cumulative design value can be set automatically according to the volume and concentration of the dissolving tank 12. Star feeder 8: When the weighing and metering of screw conveyor 9 reaches the cumulative design value, it will stop for protection after 60 seconds; Screw conveyor 9: When the weighing value of screw conveyor 9 reaches the cumulative design value, it will stop for protection after 120 seconds; Lower electric slide gate 10: When the weighing value of screw conveyor 9 reaches the cumulative design value, the protection will stop after 120 seconds; Each valve in the feeding system is protected by a delayed closing mechanism to ensure that no calcium hydroxide powder accumulates in the star feeder 8, screw conveyor 9, and pipeline 11 during the shutdown period. This prevents caking from occurring during prolonged shutdown, which could affect the accuracy of lime slurry preparation and the safety of the equipment during the next startup. (6) The starting method of the feeding system is as follows: When the system receives the feeding signal, it first opens the lower electric slide gate 10. When the lower electric slide gate 10 is fully open, the screw conveyor 9 is started. After running for 15 seconds, the star feeder 8 is started. The initial frequency of the star feeder 8 is 15 Hz. After running for 15 seconds, the upper electric slide gate 7 is started, and the system begins feeding. During the feeding process, the system dynamically corrects the frequency of the star feeder 8 (fine-tuning) according to the feeding speed of the screw conveyor 9, ensuring uniform and stable feeding and ensuring that the density deviation of lime slurry is ≤ ±1%. When the feeding system starts, the low-frequency oscillator 5 is dynamically adjusted by PID according to the calcium hydroxide powder silo level and the feeding amount of the screw conveyor. (7) The method for shutting down the feeding system is as follows: When the system receives a stop feeding signal, it first closes the upper electric slide gate 7, then stops the star feeder 8 after 60 seconds, and then stops the screw conveyor 9 and the lower electric slide gate 10 after 120-130 seconds. This ensures that after the system stops, the material in the star feeder 8, screw conveyor 9 and pipe 11 is completely discharged, preventing compaction and caking due to prolonged shutdown.

[0018] After adopting this device and method, the metering accuracy of calcium hydroxide powder silo reaches over 95%, the dosage fluctuation is within ±3%, the pH compliance rate of waste acid water neutralization is >98%, the consumption of calcium hydroxide powder is reduced by 10%, the density fluctuation of lime slurry solution is controlled within ±1%, and the blockage frequency is ≤0.5 times / week.

Claims

1. An apparatus for stabilizing operation of a milk of lime production system, characterized by, The application relates to a calcium hydroxide powder bin storage metering system and a calcium hydroxide powder discharging and weighing metering system, wherein the calcium hydroxide powder bin storage metering system comprises a calcium hydroxide powder bin, a radar material level meter, a high-resistance rotary material level meter and a low-resistance rotary material level meter; the upper part of the calcium hydroxide powder bin is a cylinder, and the lower part is a cone; the radar material level meter is installed at the top of the calcium hydroxide powder bin; the high-resistance rotary material level meter and the low-resistance rotary material level meter are both installed on the side wall of the cylinder of the calcium hydroxide powder bin and are arranged on the same side in a top-down mode; the calcium hydroxide powder discharging and weighing metering system comprises two low-frequency oscillators, a manual plug-in door, an upper electric plug-in door, a star-shaped feeder, a screw conveyor and a lower electric plug-in door; the two low-frequency oscillators are symmetrically installed on the two sides of the cone of the calcium hydroxide powder bin and are located at the expansion joints of the upper part of the cone; the lower part of the cone is connected with a pipeline; the pipeline is sequentially connected with the manual plug-in door, the upper electric plug-in door, the star-shaped feeder, the screw conveyor and the lower electric plug-in door; the manual plug-in door, the upper electric plug-in door, the star-shaped feeder, the screw conveyor, the lower electric plug-in door and the pipeline are connected through flanges; the oscillators, the star-shaped feeder and the screw conveyor are cooperatively closed-loop discharging; the lower electric plug-in door is connected with a lime milk dissolving tank through the pipeline; the radar material level meter, the high-resistance rotary material level meter, the low-resistance rotary material level meter, the low-frequency oscillators, the upper electric plug-in door, the star-shaped feeder, the screw conveyor and the lower electric plug-in door are all connected with a shutdown safety protection interlocking logic control system.

2. A device for stabilizing the operation of a milk of lime production system according to claim 1, characterized in that, The high-resistance rotary material level meter is arranged at a position 1m away from the top of the calcium hydroxide powder bin, and the low-resistance rotary material level meter is arranged at a position 0.5m away from the upper end of the cone of the calcium hydroxide powder bin; the two rotary material level meters are of the same specification.

3. A device for stabilizing the operation of a milk of lime production system according to claim 1, characterized in that, The motor of the star-shaped feeder is a variable-frequency motor, and the screw conveyor is provided with an automatic weighing meter.

4. The device for stabilizing the operation of a milk of lime production system according to claim 1, characterized in that, The two low-frequency oscillators are simultaneously started and stopped; when the system is started, the oscillation is carried out once every 10 minutes, and the vibration duration is 20 seconds; when the system is stopped, the oscillation is carried out once every 60 minutes, and the vibration duration is 10 seconds, so that the material is prevented from being excessively vibrated and compacted when the system is stopped.

5. A method of stabilizing the operation of a milk of lime production system based on the apparatus of claim 1, characterized in that, The application comprises the following contents: (1) multi-stage material level redundant detection: the data of the high-resistance rotary material level meter, the low-resistance rotary material level meter and the radar material level meter are cross-verified; when any device is faulty, the main control signal source is automatically switched, so that the material level monitoring and the lime milk preparation are ensured to be continuously operated; (2) three-stage cooperative discharging of the low-frequency oscillator, the star-shaped feeder and the screw conveyor: the vibration frequency of the low-frequency oscillator is linked with the material level of the calcium hydroxide powder bin; when the material level is higher than 50%, the vibration duration of the low-frequency oscillator is set to 10-15S, and the oscillation is carried out once every 30-40 minutes; when the material level is lower than 50%, the vibration duration of the low-frequency oscillator is set to 15-20S, and the oscillation is carried out once every 15-20 minutes; during the operation process, the oscillation period is dynamically adjusted according to the material level change and the PID of the discharging amount of the screw conveyor; the rotating speed of the motor of the star-shaped feeder is dynamically adjusted according to the discharging speed of the screw conveyor, so that the star-shaped feeder is prevented from being blocked due to too fast discharging; the low-frequency oscillator is prevented from breaking the arch of the powder; the star-shaped feeder is prevented from being blocked; and the screw conveyor is prevented from being blocked; the low-frequency oscillator breaks the arch of the powder, the star-shaped feeder quantitatively intercepts and prevents the blockage, and the screw conveyor stably conveys the flow; (3) closed-loop metering of the star-shaped feeder variable-frequency + screw conveyor: feedforward control: the star-shaped feeder is set with an initial rotating speed of 15-20 HZ according to the preset flow rate; Feedback control: the screw conveyor weighing module measures the actual flow in real time, and the PLC dynamically corrects the frequency of the star feeder to ensure uniform and stable discharging and ensure that the density deviation of lime milk is ≤±1%; (4) The upper and lower electric plug doors are used for safety isolation: When any device in the discharging system fails and needs to be shut down urgently, the upper electric plug door is closed, and the response time is ≤20 seconds. During shutdown or maintenance, the lower electric plug door is closed to block the wet gas backflow of the lime milk dissolving tank, prevent the screw conveyor and the star feeder from being damp and solidified, prevent the motor from being overloaded and burned out or the calcium hydroxide powder feeding amount from fluctuating when starting again, and prevent external moisture from entering or quickly shutting down the powder bin. (5) Shutdown logic for interlocking protection of the discharging system: Upper electric plug door: when the screw conveyor weighing measurement reaches the cumulative design value, it is protected and stopped, and the cumulative design value can be set according to the volume of the dissolving tank and the concentration of the mixture. Star feeder: when the screw conveyor weighing measurement reaches the cumulative design value, it is protected and stopped after 60 seconds. Screw conveyor: when the screw conveyor weighing measurement reaches the cumulative design value, it is protected and stopped after 120 seconds. Lower electric plug door: when the screw conveyor weighing measurement reaches the cumulative design value, it is protected and stopped after 120 seconds. By implementing the time delay closing protection for each valve in the discharging system, it is ensured that there is no calcium hydroxide powder accumulated in the star feeder, screw conveyor, and pipeline of the discharging system during shutdown, preventing solidification and affecting the accuracy of lime milk preparation and the safety of the equipment during the next start-up.

6. A method of stabilizing the operation of a milk of lime production system according to claim 5, characterized in that, The method for starting the discharging system is as follows: When the system receives the discharging signal, the lower electric plug door is opened first, the screw conveyor is started when the electric plug door is opened to the position, the star feeder is started after 15-20 seconds, the initial frequency of the star feeder is 15-20 HZ, the upper electric plug door is started after 15-20 seconds, and the system starts discharging. During the discharging process, the system dynamically corrects the fine-tuning frequency of the star feeder according to the discharging speed of the screw conveyor to ensure uniform and stable discharging and ensure that the density deviation of lime milk is ≤±1%. When the discharging system starts, the low-frequency oscillator dynamically adjusts according to the powder bin level and the discharging amount of the screw conveyor.

7. The method of claim 5, wherein the method further comprises, The method for stopping the discharging system is as follows: When the system receives the stop discharging signal, the upper electric plug door is closed first, the star feeder is stopped after 60-70 seconds, the screw conveyor and the lower electric plug door are stopped after 120-130 seconds, and it is ensured that the materials in the star feeder, screw conveyor, and pipeline are completely discharged to prevent solidification during long-term shutdown.

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