Power plant sludge pump process control optimization method

Abstract

The invention provides a power plant sludge pump process control optimization method, and belongs to the technical field of power plant automation control. The sludge pump can at least partially solve the problems that the displacement cannot be accurately matched, the pipeline is easy to block, and the pump body is burnt out due to the fact that the control of the existing sludge pump depends on easily blocked pressure measuring points and unreliable manual flushing. The method comprises the following steps: acquiring a real-time liquid level of a clarification tank, and automatically starting sequence control when the liquid level reaches a high threshold value; in sequence control, effective flushing is ensured by monitoring the flow of flushing water; during the sludge pumping and discharging period, continuously monitoring the outlet flow of the sludge pump; and when the outlet flow is lower than an operation failure threshold value or the liquid level of the clarification tank is lower than a low threshold value, the pump stopping step is automatically executed. The automatic control system has the beneficial effects that closed-loop automatic control is realized by introducing the liquid level meter and the outlet flow meter, and a pressure measuring point which is easy to block is replaced by outlet flow monitoring, so that the problem that the pump body is burnt due to idling is fundamentally avoided.

Description

Technical Field

[0001] This invention belongs to the field of power plant automation control technology, specifically relating to a method for optimizing the process control of a power plant sludge pump. Background Technology

[0002] In the desulfurization wastewater treatment system of thermal power plants, sludge pumps play a key role, responsible for pumping the sludge settled in the clarification tank to the subsequent vacuum belt conveyor for dewatering.

[0003] The existing sludge pump process has revealed many shortcomings in actual operation: First, the existing flushing operation relies on manual operation by operators. The frequency, duration, and timing of flushing are entirely controlled manually, lacking unified standards and effectiveness verification, which cannot guarantee the flushing effect, leading to increasingly serious problems of sludge adhesion in the sludge pump pipelines and pump body.

[0004] Secondly, the system relies on pressure monitoring points to monitor its operational status. However, the viscous and easily solidified sludge medium causes frequent blockages in the sampling pipelines of the pressure monitoring points. When the monitoring points are blocked, the control system cannot obtain the actual pipeline pressure, thus losing effective monitoring of the system's operational status.

[0005] Finally, and most seriously, when the pipes are blocked or the sludge in the clarifier is emptied, if the pressure gauges have failed, the control system will not detect the abnormality, and the sludge pump will enter an "idling" state. Prolonged idling can cause the pump body to overheat, the mechanical seal to be damaged, and even the motor to burn out (commonly known as "pump burnout"). This not only causes equipment damage and high maintenance costs, but also affects the stability of the entire desulfurization wastewater treatment process due to system shutdown, bringing environmental risks.

[0006] In addition, existing manual or timed control methods cannot accurately match the sludge discharge volume according to the actual sludge accumulation in the clarifier, which can easily lead to excessive sludge accumulation or discharge in the system, affecting the stability and treatment effect of the entire desulfurization wastewater treatment process.

[0007] Therefore, there is an urgent need for a process control optimization method for sludge pumps that can operate automatically and reliably and effectively prevent the pump body from burning out due to dry running. Summary of the Invention

[0008] The present invention aims to solve at least one of the technical problems existing in the prior art, and to provide a method for optimizing the process control of sludge pumps in power plants.

[0009] This invention provides a method for optimizing the process control of sludge pumps in power plants, comprising: Obtain the real-time liquid level in the clarification tank; When the real-time liquid level reaches the preset high liquid level threshold, the sludge pump control sequence is automatically activated. The sludge pump control sequence includes: Perform a rinsing step, and monitor the rinsing water flow rate during the rinsing step to determine whether the rinsing step is effective; Start the sludge pump to perform the pumping procedure; During the pumping step, the outlet flow rate of the sludge pump is continuously monitored; When the outlet flow rate is lower than the preset operation failure threshold, an alarm is triggered and the process jumps to the pump shutdown step; When the real-time liquid level in the clarification tank reaches the preset low liquid level threshold, the process jumps to the pump stop step. The pump shutdown procedure includes stopping the sludge pump and performing a post-shutdown flushing procedure.

[0010] Furthermore, the outlet flow rate being lower than the preset operational failure threshold is defined as follows: the outlet flow rate being less than 5T / H and lasting for 5 seconds.

[0011] Furthermore, the preset high liquid level threshold is 2.5 meters, and the preset low liquid level threshold is 0.3 meters.

[0012] Furthermore, the outlet flow rate of the sludge pump is monitored by a probe-type flow meter installed outside the sludge pipeline.

[0013] Further, determining whether the rinsing step is effective includes: The flushing step is confirmed to be successful and proceeds to the next step only when the flushing water flow rate is detected to be greater than the preset flushing flow rate threshold and continues for the preset flushing time.

[0014] Furthermore, the preset flushing flow rate threshold is 10T / H, and the preset flushing duration is 60 seconds.

[0015] Furthermore, the sludge pump control sequence specifically includes the following steps: Step 1: Open the sludge pump inlet valve; Step 2: Open the flushing water valve and monitor the flushing water flow rate to ensure it exceeds the preset flushing flow rate threshold for a first preset duration; Step 3: Close the sludge pump inlet valve; Step 4: Open the secondary valve at the sludge pump inlet; Step 5: Start the sludge pump and monitor that the outlet flow rate of the sludge pump is greater than the preset start-up threshold; Step 6: Open the sludge pump inlet door, and the sludge pump will continue to run; Step 7: Close the flushing water valve, and the sludge pump continues to perform the pumping step until the real-time liquid level is lower than the preset low liquid level threshold. Step 8: Open the flushing water valve; Step 9: Close the sludge pump inlet door and continue flushing for the second preset time; Step 10: Perform the pump shutdown procedure to stop the sludge pump; Step 11: Close the secondary valve at the inlet of the sludge pump; Step 12: Open the sludge pump inlet door and continue flushing for a third preset time; Step 13: Close the sludge pump inlet valve; Step 14: Close the flushing water valve, and the sludge pump control sequence ends.

[0016] Furthermore, during any of the execution of steps 5, 6, 7, and 9, if the sludge pump outlet flow rate is less than the operational failure threshold, the process immediately jumps to step 10.

[0017] Furthermore, steps 2 and 12 are used to flush the first pipeline section from the sludge pump inlet gate to the clarifier.

[0018] Furthermore, steps 5 and 9 are used to flush the sludge pump inlet secondary valve, the sludge pump, and the sludge pump outlet pipe.

[0019] The beneficial effects of this invention are as follows: Achieving closed-loop control and precise discharge: By introducing a clarifier level gauge, a closed-loop control system of "automatic start at high levels and automatic stop at low levels" is achieved. This completely changes the original fixed-duration or manual start / stop mode, ensuring that the sludge discharge rate precisely matches the actual demand and avoiding excessive accumulation or emptying of sludge in the clarifier.

[0020] Preventing pump burnout due to dry running: The core improvement of this invention lies in replacing the easily clogged pressure measuring point with a sludge pump outlet flow meter. The control system continuously monitors the actual flow rate during pump operation. Once the flow rate falls below the operational failure threshold (indicating blockage or emptying), the pump is immediately forced to stop and an alarm is triggered. This logic fundamentally eliminates the possibility of sludge pumps burning out due to dry running, ensuring equipment safety.

[0021] Improved flushing reliability: By adding a flushing water flow meter, the control system can determine whether the flushing operation is "effective." The system only proceeds to the next step when sufficient flushing water flow is detected, ensuring the quality of each automatic flush and effectively reducing pipe and valve blockage.

[0022] Improving automation and reducing labor costs: Fully automated sequential control logic replaces the original manual operation, significantly reducing the inspection and maintenance burden on operators and reducing labor costs caused by pipeline blockage, sludge pump disassembly and cleaning, and maintenance.

[0023] Reduced environmental risks: The system ensures long-term, high-reliability operation of the sludge pump system and guarantees the overall stability of the desulfurization wastewater treatment process, thereby reducing the risk of exceeding environmental standards due to system failure. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the basic process flow of the sludge pump process control optimization method according to an embodiment of the present invention; Figure 2 This is a diagram of the sludge pump process control system according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the process state of sequential control steps 1 to 2 in an embodiment of the present invention; Figure 4 This is a schematic diagram of the process state of sequential control steps 3 to 6 in an embodiment of the present invention; Figure 5 This is a schematic diagram of the process state of step 7 in the sequential control embodiment of the present invention; Figure 6 This is a schematic diagram of the process state of sequential control steps 8 to 10 in an embodiment of the present invention; Figure 7 This is a schematic diagram of the process state of sequential control steps 11 to 12 in an embodiment of the present invention.

[0025] In the picture: 1-Sludge pump outlet flow meter, 2-Sludge pump, 3-Sludge pump inlet secondary valve, 4-Sludge pump inlet valve, 5-Clarification tank, 6-Flush water flow meter, 7-Flush water valve, 8-Sludge pipe, 9-Flush water pipe, 10-Clarification tank level gauge. Detailed Implementation

[0026] To make the objectives, technical solutions, and beneficial effects of this application clearer, the following detailed description, in conjunction with the accompanying drawings and specific embodiments, further illustrates this application. It should be understood that the specific embodiments described in this specification are merely for explaining this application and are not intended to limit it.

[0027] Please see Figure 1 and Figure 2 This invention provides a method for optimizing the process control of a power plant sludge pump. The main implementers of this method are the power plant's distributed control system (DCS) and programmable logic controller (PLC), and the controlled object is... Figure 2 The sludge pump process system shown.

[0028] The sludge pump process system includes: Clarification tank 5 is used to store the treated sludge liquid; A clarifier level gauge 10 is installed on the clarifier tank 5. Sludge is discharged through a sludge pipe 8, which is sequentially equipped with a sludge pump inlet valve 4 and a sludge pump inlet secondary valve 3. The sludge pump 2 provides the power for pumping. A sludge pump outlet flow meter 1 is installed on the outlet pipe of the sludge pump 2.

[0029] The flushing water pipe 9 is used to supply flushing water, and it is equipped with a flushing water valve 7 and a flushing water flow meter 6. The connection point of the flushing water pipe 9 is located between the sludge pump inlet valve 4 and the sludge pump inlet secondary valve 3.

[0030] The embodiments of the present invention have made key optimizations to the sensor, which is a prerequisite for realizing the method of the present invention: Elimination of pressure measuring points: Given the inherent defect that pressure measuring points are prone to clogging in sludge media, this solution eliminates the original pressure measuring points.

[0031] Add an outlet flow meter 1: This flow meter uses a probe externally mounted against the pipe wall. Its probe does not directly contact the sludge liquid, fundamentally avoiding clogging problems. This flow meter is the core measuring point for pump protection.

[0032] Add a flushing water flow meter 6: to monitor the flushing water flow in real time and ensure the effectiveness of the flushing operation.

[0033] Adding a clarifier level gauge 10: This is used to accurately sense the sludge level in the clarifier, which is the basis for achieving automatic start-up and shutdown and precise discharge.

[0034] The core of this invention lies in an automated sludge pump control system based on the aforementioned optimized measuring points. This control system is automatically triggered and stopped by the control system (DCS) according to the signal from the clarifier level gauge 10.

[0035] Sequential start-up and pre-run flushing: The control system continuously monitors the real-time liquid level of the clarifier level gauge 10. When the real-time liquid level exceeds the preset high liquid level threshold (which is set to 2.5 meters), it indicates that enough sludge has accumulated in the clarifier and needs to be treated. The control system then automatically starts the sludge pump control sequence.

[0036] Please refer to Figure 3 After sequential start-up, the first step is to flush the pipeline before the pump: Step 1: Open sludge pump inlet valve 4. After sludge pump inlet valve 4 is fully opened, proceed to the next step.

[0037] Step 2: Open the flushing water valve 7. At this time, the flushing water flows back through the flushing water pipe 9 and the sludge pump inlet valve 4 to the clarifier 5. This step is used to flush the first pipe section from the sludge pump inlet valve 4 to the clarifier 5. The control system starts monitoring the reading of the flushing water flow meter 6. When the reading is greater than the preset flushing flow threshold (10T / H) and remains so for a first preset duration (60 seconds), the control system determines that the flushing is effective and the pipe is unobstructed. Step 2 is successful, proceed to the next step.

[0038] Pump start-up and pumping: Please refer to Figure 4 Perform flushing and startup of the pump body and outlet pipeline: Step 3: Close sludge pump inlet valve 4. After sludge pump inlet valve 4 is closed, proceed to the next step.

[0039] Step 4: Open the secondary valve 3 at the sludge pump inlet. After the secondary valve 3 at the sludge pump inlet is fully opened, proceed to the next step.

[0040] Step 5: Start sludge pump 2. At this time, flushing water flows through flushing water pipe 9, sludge pump inlet secondary valve 3, sludge pump 2, and outlet pipe 8 for forward flushing. This step is used to flush the sludge pump inlet secondary valve 3, the sludge pump 2, and the sludge pump outlet pipe. The control system monitors the reading of sludge pump outlet flow meter 1. When the outlet flow rate is greater than the preset start-up threshold (10T / H) and remains so for 60 seconds, it is determined that the pump and outlet pipe are unobstructed, and step 5 is successfully completed.

[0041] Specifically, during the execution of step 5, the control system introduces a start-up failure protection logic: if, after starting sludge pump 2, the reading of outlet flow meter 1 remains below the operation failure threshold (which is 5T / H) for 5 seconds, it indicates that the pump has failed to start or that the inlet is severely blocked. The control system will immediately determine that the sequential control has failed and jump to step 10 (stopping the sludge pump), while simultaneously triggering a "sludge pump blockage alarm" to the DCS.

[0042] Please refer to Figure 5 The formal sludge removal phase has begun. Step 6: Open sludge pump inlet valve 4. After sludge pump inlet valve 4 is fully open, sludge pump 2 begins to draw sludge from clarifier 5. Sludge pump 2 runs continuously for 180 seconds (this is a stable operating time), indicating that step 6 of the sequential control is successful.

[0043] Step 7: Close flushing water valve 7. Sludge pump 2 officially enters the pure sludge pumping operation mode.

[0044] Throughout the entire pumping and drainage operation in steps 6 and 7, the control system will continuously and frequently monitor two key signals: Normal stop signal: Real-time liquid level of clarifier level gauge 10.

[0045] Abnormal stop signal: Real-time flow rate of sludge pump outlet flow meter 1.

[0046] The sequential control will end the sampling process and proceed to the next step when any of the following conditions are met: Condition 1 (Normal Stop): The control system detects that the real-time liquid level of the clarifier level gauge 10 is lower than the preset low liquid level threshold (0.3 meters). This indicates that the sludge in the clarifier has been discharged as required, achieving precise discharge control.

[0047] Condition 2 (Abnormal Stop): The control system detects that the reading of the sludge pump outlet flow meter 1 is less than the aforementioned operational failure threshold (5T / H) for 5 consecutive seconds. This indicates that a pipe blockage has occurred during the pumping process, or that the sludge has been prematurely discharged, causing the pump to operate without water.

[0048] Regardless of the triggering condition, this closed-loop control logic ensures that sludge pump 2 immediately stops ineffective or dangerous operation, thereby preventing pump body burnout.

[0049] Pump shutdown and post-shutdown flushing: Please refer to Figure 6 Once the stopping condition in step 7 is met, the sequential control jump will execute the pre-pump shutdown flushing: Step 8: Open the flushing water valve 7.

[0050] Step 9: Close sludge pump inlet valve 4. At this time, flushing water performs a final flush on the pump body and outlet pipe to prevent sludge from solidifying inside the pump. After flushing for a second preset time (180 seconds), the system is deemed to have successfully completed step 9. During the execution of step 9, the control system will also monitor the outlet flow rate. If the flow rate is less than 5 T / H, an alarm will be triggered and the system will directly jump to step 10.

[0051] Step 10: Perform the pump shutdown procedure to stop sludge pump 2.

[0052] Please refer to Figure 7 Perform pipeline flushing after pump shutdown: Step 11: Close the secondary valve 3 at the sludge pump inlet.

[0053] Step 12: Open sludge pump inlet valve 4. The flushing water backwashes the inlet pipe (i.e., the first pipe section) for the third preset time (60 seconds).

[0054] Step 13: Close the sludge pump inlet valve 4.

[0055] Step 14: Close the flushing water valve 7.

[0056] At this point, all 14 steps have been completed, ending a full, safe, and automated sludge removal and anti-clogging flushing cycle. The system will return to standby mode, waiting for the clarifier level to reach the high threshold again before restarting the sequential control.

[0057] In summary, the embodiments disclosed herein have at least the following technical effects: Achieving closed-loop control and precise discharge: By introducing a clarifier level gauge, a closed-loop control system of "automatic start at high levels and automatic stop at low levels" is achieved. This completely changes the original fixed-duration or manual start / stop mode, ensuring that the sludge discharge rate precisely matches the actual demand and avoiding excessive accumulation or emptying of sludge in the clarifier.

[0058] Preventing pump burnout due to dry running: The core improvement of this invention lies in replacing the easily clogged pressure measuring point with a sludge pump outlet flow meter. The control system continuously monitors the actual flow rate during pump operation. Once the flow rate falls below the operational failure threshold (indicating blockage or emptying), the pump is immediately forced to stop and an alarm is triggered. This logic fundamentally eliminates the possibility of sludge pumps burning out due to dry running, ensuring equipment safety.

[0059] Improved flushing reliability: By adding a flushing water flow meter, the control system can determine whether the flushing operation is "effective." The system only proceeds to the next step when sufficient flushing water flow is detected, ensuring the quality of each automatic flush and effectively reducing pipe and valve blockage.

[0060] Improving automation and reducing labor costs: Fully automated sequential control logic replaces the original manual operation, significantly reducing the inspection and maintenance burden on operators and reducing labor costs caused by pipeline blockage, sludge pump disassembly and cleaning, and maintenance.

[0061] Reduced environmental risks: The system ensures long-term, high-reliability operation of the sludge pump system and guarantees the overall stability of the desulfurization wastewater treatment process, thereby reducing the risk of exceeding environmental standards due to system failure.

[0062] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A power plant sludge pump process control optimization method, characterized by, The method comprises: acquiring a real-time liquid level of a clarifier; starting a sludge pump control sequence when the real-time liquid level reaches a preset high liquid level threshold; the sludge pump control sequence comprises: performing a flushing step, and monitoring a flushing water flow during the flushing step to determine whether the flushing step is effective; starting the sludge pump to perform a pumping step; continuously monitoring an outlet flow of the sludge pump during the pumping step; triggering an alarm and jumping to a pump stopping step when the outlet flow is lower than a preset operation failure threshold; jumping to the pump stopping step when the real-time liquid level of the clarifier reaches a preset low liquid level threshold; the pump stopping step comprises stopping the operation of the sludge pump and performing a post-pump stopping flushing step.

2. The process control optimization method of claim 1, wherein, The outlet flow being lower than the preset operation failure threshold means that the outlet flow is less than 5 T / H and lasts for 5 seconds.

3. The process control optimization method of claim 1, wherein, The preset high liquid level threshold is 2.5 meters, and the preset low liquid level threshold is 0.3 meters.

4. The process control optimization method of claim 1, wherein, The monitoring of the outlet flow of the sludge pump is achieved by a probe flowmeter installed outside a sludge pipeline.

5. The process control optimization method of claim 1, wherein, The determination of whether the flushing step is effective comprises: only when the flushing water flow is greater than a preset flushing flow threshold and lasts for a preset flushing duration, it is determined that the flushing step is successful and the next step is entered.

6. The process control optimization method of claim 5, wherein, The preset flushing flow threshold is 10 T / H, and the preset flushing duration is 60 seconds.

7. The process control optimization method of claim 1, wherein, The sludge pump control sequence specifically comprises the following steps: Step 1: opening a sludge pump inlet door; Step 2: opening a flushing water door and monitoring a flushing water flow greater than a preset flushing flow threshold and lasting for a first preset duration; Step 3: closing the sludge pump inlet door; Step 4: opening a sludge pump inlet secondary door; Step 5: starting the sludge pump and monitoring an outlet flow of the sludge pump greater than a preset starting threshold; Step 6: opening the sludge pump inlet door, and the sludge pump continuously operates; Step 7: closing the flushing water door, and the sludge pump continuously performs the pumping step until the real-time liquid level is lower than the preset low liquid level threshold; Step 8: opening the flushing water door; Step 9: closing the sludge pump inlet door and continuously flushing for a second preset duration; Step 10: performing the pump stopping step to stop the sludge pump; Step 11: closing the sludge pump inlet secondary door; Step 12: opening the sludge pump inlet door and continuously flushing for a third preset duration; Step 13: closing the sludge pump inlet door; Step 14: closing the flushing water door, and the sludge pump control sequence ends.

8. The process control optimization method of claim 7, wherein, During the execution of any one of the steps 5, 6, 7 and 9, if the outlet flow of the sludge pump is less than the operation failure threshold, the step 10 is immediately jumped to.

9. The process control optimization method of claim 7, wherein, The steps 2 and 12 are used to flush a first pipeline section of the sludge pump inlet door to the clarifier.

10. The process control optimization method of claim 7, wherein, The steps 5 and 9 are used to flush the sludge pump inlet secondary door, the sludge pump and an outlet pipeline of the sludge pump.

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