A ph electrode rinsing device, desulfurization absorption tower system and control method

Abstract

This invention discloses a pH electrode flushing device, a desulfurization absorption tower system, and a control method. The pH electrode flushing device includes an industrial water flushing pipeline filter, a check valve, an industrial water inlet manual valve, and an industrial flushing solenoid valve connected in sequence. An annular flushing opening pipe extending obliquely into the electrode flow tank is provided at the upper part of the electrode flow tank. Multiple sets of flushing nozzles are provided on the annular flushing opening pipe. The annular flushing opening pipe is connected to the industrial water flushing solenoid valve. An inlet pipe is provided on one side of the lower part of the electrode flow tank. A drain pipe is provided at the lower part of the electrode flow tank. The bottom of the drain pipe is connected to the side wall of the top of the electrode flow tank through the flow tank overflow pipe. A pH electrode is provided at the top center of the electrode flow tank. It has the advantages of high monitoring accuracy, more stable operation, fast adjustment response, and small control fluctuation.

Description

Technical Field

[0001] This invention relates to the field of industrial flue gas desulfurization and environmental protection technology, and in particular to a pH electrode flushing device, a desulfurization absorption tower system and a control method. Background Technology

[0002] In lime / limestone wet FGD desulfurization systems, the pH value of the circulating slurry in the absorber tower is a core process parameter affecting desulfurization efficiency, absorbent utilization rate, gypsum purity, and system scaling, clogging, and corrosion. Engineering operation shows that: the higher the slurry pH value, the stronger the SO2 absorption capacity, but the limestone dissolution rate decreases sharply, resulting in excess unreacted limestone and reduced gypsum purity; conversely, a pH value that is too low reduces desulfurization efficiency, weakens the slurry absorption capacity, and may even cause limestone activation blockage, affecting the stable operation of the system. In wet desulfurization systems, the pH value of the slurry is a key parameter for controlling desulfurization efficiency, limestone consumption, and gypsum quality. High solids content and severe gypsum crystallization in the desulfurization slurry make it highly susceptible to scaling on the surface of the pH electrode's sensitive membrane, leading to measurement drift, slow response, and electrode poisoning failure.

[0003] Existing desulfurization pH monitoring and adjustment technologies have significant shortcomings: 1) Single-point pH measurement is easily affected by uneven slurry distribution and flow field fluctuations, resulting in large measurement lag and low accuracy; 2) Relying solely on PID control results in a slow response speed, making it unable to adapt to rapid fluctuations in unit load and inlet SO2 concentration; 3) The pH setting is fixed and cannot be dynamically optimized according to the working conditions, making it difficult to balance desulfurization efficiency and gypsum quality. 4) Lack of full-cycle protection logic, which can easily lead to scaling due to excessively high pH or corrosion due to excessively low pH.

[0004] 5) Traditional maintenance methods involve manual offline disassembly and cleaning, which requires shutting down the measuring points and removing the electrodes. This is labor-intensive, interrupts monitoring, and affects the system's automatic control. Existing online flushing devices mostly use single-sided direct flushing, which creates blind spots and easily damages the electrode membrane. Some devices lack stable overflow and effective drainage structures, which can easily lead to sedimentation and bubbles, resulting in measurement distortion.

[0005] This application provides a pH electrode flushing device, a desulfurization absorption tower system, and a control method to solve the above-mentioned problems. Summary of the Invention

[0006] The main objective of this invention is to address the following issues in existing technologies: single-point pH measurement is easily affected by uneven slurry distribution and flow field fluctuations, resulting in large measurement lag and low accuracy; relying solely on a single PID controller leads to slow response speeds, making it unable to adapt to rapid fluctuations in unit load and inlet SO2 concentration; fixed pH setpoints cannot be dynamically optimized according to operating conditions, making it difficult to balance desulfurization efficiency and gypsum quality; the lack of full-cycle protection logic easily leads to scaling due to excessively high pH or corrosion due to excessively low pH; traditional maintenance methods involve manual offline disassembly and cleaning, requiring shutdown of the measuring point and disassembly of the electrode, resulting in a large workload, monitoring interruption, and impact on system automatic control. Existing online flushing devices mostly use single-sided direct flushing, resulting in flushing dead zones that are easily damaged by impact; some devices lack stable overflow and effective sewage discharge structures, easily generating sediment and bubbles, leading to measurement distortion.

[0007] This invention provides a pH electrode flushing device, a desulfurization absorption tower system, and a control method. The pH electrode flushing device includes: The system includes an industrial water flushing solenoid valve, an industrial water inlet manual valve, a check valve, an industrial water flushing pipeline filter, a sewage discharge manual valve, a sewage discharge solenoid valve, an electrode flow tank, a pH electrode, a liquid inlet manual valve, a liquid inlet electric valve, an annular flushing opening pipe, and multiple sets of flushing nozzles. The industrial water flushing pipeline filter, check valve, industrial water inlet manual valve, and industrial flushing solenoid valve are connected in sequence. The upper part of the electrode flow tank is provided with an annular flushing opening pipe that extends obliquely into the electrode flow tank. Multiple sets of flushing nozzles are provided on the annular flushing opening pipe. The annular flushing opening pipe is connected to the industrial water flushing solenoid valve. A liquid inlet pipe is provided on one side of the lower part of the electrode flow tank. A sewage discharge pipe is provided at the lower part of the electrode flow tank. The bottom of the sewage discharge pipe is connected to the side wall of the top of the electrode flow tank through the flow tank overflow pipe. A pH electrode is provided at the top center of the electrode flow tank.

[0008] Furthermore, the liquid inlet pipeline includes a manual liquid inlet valve and a power liquid inlet valve, which are sequentially connected to the electrode flow cell.

[0009] Furthermore, the sewage discharge pipeline includes: a manual sewage discharge valve and a solenoid sewage discharge valve. One end of the manual sewage discharge valve is connected to the electrode flow tank, and the other end of the manual sewage discharge valve is connected to the solenoid sewage discharge valve. The solenoid sewage discharge valve is also connected to the sewage overflow pipe and the sewage tank.

[0010] Furthermore, the diameter of the rinsing nozzle is 1-3 mm, and the spray direction of the nozzle is at an angle of 30°-60° to the axis of the pH electrode.

[0011] Furthermore, the elevation of the overflow pipe (8) is ≥50mm higher than the top of the pH electrode sensitive membrane.

[0012] Furthermore, the sewage discharge solenoid valve, the liquid inlet electric valve, and the industrial water flushing solenoid valve are all electrically connected to the DCS system.

[0013] On the other hand, this application also provides a desulfurization absorption tower system equipped with a pH electrode flushing device, comprising: the pH electrode flushing device and a spray tower as described above, wherein the spray tower is provided with a first spray layer, a second spray layer, a flue gas inlet channel, an oxidation blower, a limestone slurry supply pump, a circulating slurry pump, and a gypsum slurry delivery pump in sequence from top to bottom; the first spray layer is connected to external industrial water; the second spray layer is simultaneously connected to two circulating slurry pumps; both circulating slurry pumps are simultaneously connected to the spray tower; and the second spray layer and the two circulating slurry pumps are connected to the spray tower. The slurry pump is connected to the inlet pipe of the pH electrode flushing device. The flue gas inlet channel is connected outward to the flue gas sulfur dioxide content monitoring device and the flue gas flow sensor. The oxidation fan is located below the flue gas inlet channel and is connected to the inside of the spray tower. A slurry density meter is located below the oxidation fan. The pH electrode flushing device is located below the slurry density meter. A limestone slurry supply pump is located below the pH electrode flushing device. The spray tower located directly opposite the limestone slurry supply pump is connected to a gypsum slurry delivery pump.

[0014] On the other hand, this application also provides a control method for a desulfurization absorption tower system equipped with a pH electrode flushing device, used in the aforementioned desulfurization absorption tower system equipped with a pH electrode flushing device, comprising: The pH values ​​at the two pH electrode flushing devices are obtained. After the measurement drift caused by the temperature compensation module is eliminated, the pH values ​​are entered into the signal processing unit for weighted average filtering to remove instantaneous interference, jump values ​​and deviations caused by slurry unevenness. The real-time equivalent pH value is output as the sole basis for system control. pH setting control logic: minimum pH protection value 5.0, maximum protection value 6.0; the system reads the SO2 concentration signal at the CEMS inlet in real time and automatically generates the pH setting value according to the following rules: pH value is set to 5.3 when SO2 concentration < 800 mg / m³; pH value is set to 5.5 when SO2 concentration is 800-1500 mg / m³; pH value is set to 5.7 when SO2 concentration > 1500 mg / m³. Collect the inlet flue gas flow rate and CEMS inlet SO2 concentration, calculate the total SO2 = flue gas flow rate × SO2 concentration, and directly output the limestone slurry supply benchmark quantity. The system collects the real-time equivalent pH value and the pH setpoint, calculates the deviation, and outputs the correction adjustment amount through the PID algorithm. The final control signal is then output after being superimposed with the feedforward reference amount. When the real-time equivalent pH is greater than the set value, reduce the slurry supply rate; when the real-time equivalent pH is less than the set value, increase the slurry supply rate; when the real-time equivalent pH is equal to the set value, maintain the current slurry supply rate. When pH < 5.0, the interlock increases limestone slurry supply, shuts off the gypsum discharge pump, and issues an alarm; when pH > 6.0, the interlock decreases limestone slurry supply, strengthens circulation and oxidation, and activates automatic flushing. It also includes an automatic pH electrode rinsing control process, including: Intelligent rinsing is triggered when the electrode slope is <90%, the pH remains constant for ≥10 min, or the pH change is >0.5 pH / 5 min. First, open the drain solenoid valve, and then open the industrial water flushing solenoid valve after a 3-second delay. After rinsing is complete, first close the rinsing solenoid valve, then close the drain solenoid valve after a 5-second delay. When the industrial water pressure is <0.2MPa, flushing is locked, flushing is prohibited, and an alarm will sound. Do not open the flushing solenoid valve if the sewage discharge solenoid valve has not provided feedback. If the flushing time exceeds 120 seconds, the flushing solenoid valve and the drain solenoid valve will be forcibly closed and an alarm will be triggered. The flushing process is interrupted when the circulating pump stops or the desulfurization system trips.

[0015] This invention employs in-situ pH monitoring at two points: the second spray layer and the slurry pool at the bottom of the tower. Combined with temperature compensation and a weighted filtering algorithm, it effectively eliminates measurement errors caused by uneven slurry distribution and flow field fluctuations, achieving continuous, accurate, and reliable pH readings, significantly improving monitoring reliability. It utilizes a dual-closed-loop coordinated regulation system with SO2 total quantity feedforward and equivalent pH feedback. Feedforward enables rapid load tracking, while feedback provides precise correction. Compared to traditional single PID regulation, this results in faster response, smaller overshoot, and pH fluctuations controlled within ±0.1%, significantly improving control quality. The pH setpoint can be automatically and dynamically adjusted based on the inlet SO2 concentration. In low-sulfur conditions, the pH is lowered to improve gypsum purity; in high-sulfur conditions, the pH is raised to ensure desulfurization efficiency, achieving a dynamic balance between desulfurization efficiency and gypsum quality. This solves the problem of traditional fixed pH settings failing to balance efficiency and economy. The pH electrode is equipped with an automatic flushing device, eliminating the need for frequent manual cleaning, significantly reducing maintenance workload, and improving system ease of operation and automation. The 5.0–6.0 safety hard limit and high / low limit interlock protection can effectively prevent problems such as decreased desulfurization efficiency and deterioration of gypsum quality caused by excessively low pH, and limestone dissolution and passivation, slurry scaling and blockage, and equipment corrosion caused by excessively high pH. This extends the service life of the system. Under the premise of ensuring desulfurization meets the standards, it can effectively reduce the consumption of limestone slurry, improve the utilization rate of absorbent and the purity of gypsum, reduce waste emissions, increase the value of by-products, and bring direct economic benefits to the power plant. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the pH electrode rinsing device provided by the present invention.

[0017] Figure 2 This is a schematic diagram of the desulfurization absorption tower system equipped with a pH electrode flushing device provided by the present invention.

[0018] The corresponding reference numerals in the attached diagrams are as follows: 1. pH electrode flushing device; 2. Circulating slurry pump; 3. Second spray layer; 4. Industrial water flushing solenoid valve; 5. Annular flushing opening pipe; 6. pH electrode; 7. Sewage discharge solenoid valve; 8. Overflow pipe; 9. Electrode flow tank; 10. Flue gas nozzle; 11. Industrial water inlet manual valve; 12. Industrial water flushing pipe filter; 13. Check valve; 14. Liquid inlet manual valve; 15. Liquid inlet electric valve; 16. Sewage discharge manual valve; 17. Gypsum slurry delivery pump; 18. Flue gas flow sensor; 19. Flue gas sulfur dioxide content monitoring; 20. Slurry density meter; 21. Limestone slurry supply pump. Detailed Implementation The technical solution of the present invention will now be clearly and completely described in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] Example This embodiment provides a pH electrode rinsing device, including an industrial water rinsing solenoid valve 4, an industrial water inlet manual valve 11, a check valve 13, an industrial water rinsing pipeline filter 12, a sewage discharge manual valve 16, a sewage discharge solenoid valve 7, an electrode flow tank 9, a pH electrode 6, a liquid inlet manual valve 14, a liquid inlet electric valve 15, an annular rinsing opening pipe 5, and multiple sets of rinsing nozzles 10.

[0020] The industrial water flushing pipeline filter 12, check valve 13, industrial water inlet manual valve 11, and industrial flushing solenoid valve 4 are connected in sequence to form an industrial water supply passage. The industrial water flushing pipeline filter 12 is used to filter impurities in the industrial water and prevent nozzle blockage; the check valve 13 is used to prevent slurry backflow into the industrial water pipeline.

[0021] An annular flushing opening pipe 5, extending obliquely into the electrode flow cell 9, is provided at the upper part of the electrode flow cell 9. Multiple sets of flushing nozzles 10 are provided on the annular flushing opening pipe 5. The diameter of the flushing nozzles 10 is 1–3 mm, and the spray direction is at an angle of 30°–60° to the axis of the pH electrode 6, achieving 360° coverage flushing without dead angles. The annular flushing opening pipe 5 is connected to an industrial water flushing solenoid valve 4, which controls the flow of flushing water.

[0022] A liquid inlet pipe is provided on one side of the lower part of the electrode flow cell 9. The liquid inlet pipe includes a manual liquid inlet valve 14 and a power liquid inlet valve 15, which are connected to the electrode flow cell 9 in sequence. During normal operation, the manual liquid inlet valve 14 is normally open, and the power liquid inlet valve 15 is controlled by the DCS system to control the flow of slurry.

[0023] A drain pipe is installed at the bottom of the electrode flow cell 9, including a manual drain valve 16 and a solenoid drain valve 7. One end of the manual drain valve 16 is connected to the electrode flow cell 9, and the other end is connected to the solenoid drain valve 7. The solenoid drain valve 7 is also connected to the flow cell overflow pipe 8 and the drain cell. During normal operation, the manual drain valve 16 is normally open, and the solenoid drain valve 7 is controlled by the DCS system. The flow cell overflow pipe 8 connects to the side wall at the top of the electrode flow cell 9 to maintain a constant liquid level and release air. The elevation of the overflow pipe 8 is ≥50mm higher than the top of the sensitive membrane of the pH electrode 6 to ensure that the electrode is completely submerged and to release air bubbles, thus stabilizing the measurement environment.

[0024] A pH electrode 6 is installed at the top center of the electrode flow cell 9 for continuous measurement of the pH value of the slurry.

[0025] The bottom of the electrode flow tank 9 has a conical structure, which, together with the sewage discharge solenoid valve 7, thoroughly discharges the sediment, eliminates dead zones, and solves the problem of sedimentation and blockage in desulfurization slurry.

[0026] The sewage discharge solenoid valve 7, the liquid inlet electric valve 15, and the industrial water flushing solenoid valve 4 are all electrically connected to the DCS system and are uniformly controlled by the DCS system, supporting timed flushing, manual flushing, and intelligent condition-triggered flushing.

[0027] During normal measurement, the inlet electric valve 15 is opened, and the slurry enters the electrode flow tank 9 through the inlet manual valve 14 and the inlet electric valve 15. The overflow pipe 8 maintains a stable liquid level, and the pH electrode 6 is continuously monitored. During automatic flushing, the DCS triggers a sequential control program, first opening the drain solenoid valve 7, and then opening the industrial water flushing solenoid valve 4 after a 3-second delay. Industrial water enters the annular flushing opening pipe 5 through the industrial water inlet manual valve 11, check valve 13, industrial water flushing pipeline filter 12, and industrial water flushing solenoid valve 4, and is sprayed at an angle from multiple sets of flushing nozzles 10 onto the surface of the pH electrode 6, forming a swirling flow to wash away the scale layer on the electrode surface. After flushing, the industrial water flushing solenoid valve 4 is closed first, and the drain solenoid valve 7 is closed after a 5-second delay to prevent pressure buildup and slurry backflow. After flushing, the inlet electric valve 15 is reopened, the electrode flow tank 9 is refilled with slurry, and pH measurement resumes.

[0028] This device has a simple structure, reliable operation, and thorough rinsing. It can achieve online automatic rinsing without disassembling the electrodes or stopping the machine, which significantly extends the service life of the electrodes and reduces the amount of manual maintenance.

[0029] Example Reference Figure 1 This embodiment provides a desulfurization absorption tower system equipped with a pH electrode flushing device, including the pH electrode flushing device 1 and the spray tower described in Embodiment 1.

[0030] The spray tower is provided with a first spray layer, a second spray layer 3, a flue gas inlet channel, an oxidation fan, a limestone slurry supply pump 21, a circulating slurry pump 2, and a gypsum slurry delivery pump 17 from top to bottom.

[0031] The first spray layer is connected to external industrial water for demister rinsing. The second spray layer 3 is also connected to two circulating slurry pumps 2, which in turn are connected to the slurry pool at the bottom of the spray tower, forming a slurry circulation loop. The inlet pipe of the pH electrode rinsing device 1 is connected to the connecting pipe between the second spray layer 3 and the two circulating slurry pumps 2, for collecting slurry from the reaction zone of the main spray layer pipeline.

[0032] The flue gas inlet channel is connected in sequence to a flue gas sulfur dioxide content monitoring device 19 and a flue gas flow sensor 18, which are used to detect the SO2 concentration and flue gas flow rate in the inlet flue gas in real time, respectively.

[0033] An oxidation blower is installed below the flue gas inlet channel and connected to the inside of the spray tower. It is used to blow oxidizing air into the slurry tank to oxidize calcium sulfite into calcium sulfate.

[0034] A slurry density meter 20 is installed below the oxidation blower for real-time detection of slurry density.

[0035] A pH electrode flushing device 1 is installed below the slurry density meter 20, on the side wall of the slurry zone of the absorption tower, 500 mm below the liquid level, for collecting slurry from the bottom slurry pool of the tower.

[0036] A limestone slurry supply pump 21 is installed below the pH electrode rinsing device 1 to supply fresh limestone slurry to the absorption tower. A gypsum slurry delivery pump 17 is connected to a spray tower located directly opposite the limestone slurry supply pump 21 to discharge gypsum slurry to the subsequent dewatering system.

[0037] This system achieves in-situ pH monitoring at two points: the main pipeline of the spray layer and the slurry pool at the bottom of the tower. This reflects the true pH values ​​of the spray reaction zone and the slurry storage zone, respectively, eliminating measurement errors caused by slurry stratification and uneven flow field, and ensuring accurate, continuous, and reliable monitoring.

[0038] Example 3 Reference Figure 1 and Figure 2 This embodiment provides a control method for a desulfurization absorption tower system, including the following steps: Step 1: Multi-point in-situ pH online monitoring and equivalent value calculation The pH values ​​are acquired at two pH electrode flushing devices 1. The first device is installed on the main pipeline of the spray layer, reflecting the pH value of the spray reaction zone; the second device is installed on the side wall of the slurry pool at the bottom of the tower, reflecting the pH value of the slurry storage zone. The two pH electrodes 6 acquire signals in real time. After the temperature compensation module eliminates the measurement drift caused by slurry temperature changes, the signals enter the signal processing unit for weighted average filtering to eliminate instantaneous interference, jump values, and deviations caused by slurry unevenness, outputting a unique and stable real-time equivalent pH value as the sole basis for system control.

[0039] Step 2: Dynamic Adaptive pH Setpoint Generation The pH control logic is set as follows: The system has an insurmountable safety hard limit, with a minimum pH protection value of 5.0 and a maximum protection value of 6.0. The calculation result will not exceed this range under any operating condition. The normal operating condition pH reference control range is 5.2 to 5.8, and the optimal stable operating range is 5.4 to 5.6.

[0040] The system reads the SO2 concentration signal at the CEMS inlet of the flue gas sulfur dioxide content monitoring device 19 in real time and automatically generates a pH setpoint according to the following rules: when the SO2 concentration is ≤1000 mg / Nm³, the setpoint is 5.4; for every 200 mg / Nm³ increase in concentration, the setpoint is linearly increased by 0.05, with an upper limit capped at 5.6; if the concentration is ≥2000 mg / Nm³, the setpoint remains constant at 5.6. Simultaneously, a desulfurization efficiency feedback closed-loop correction is applied: when the current measured desulfurization efficiency is below 95%, the setpoint is automatically increased by 0.1 and continuously monitored until the efficiency recovers to above 95.5% before gradually decreasing.

[0041] When the SO2 concentration is <800mg / m³, the pH is set to 5.3; When the SO2 concentration is 800–1500 mg / m³, the pH is set to 5.5; When the SO2 concentration is greater than 1500 mg / m³, the pH is set to 5.7.

[0042] Step 3: Dual Closed-Loop Coordinated Regulation The main loop is for SO2 total amount feedforward regulation: the inlet flue gas flow rate of flue gas flow sensor 18 and the SO2 concentration at the inlet of CEMS of flue gas sulfur dioxide content monitoring device 19 are collected, the total SO2 is calculated as flue gas flow rate × SO2 concentration, and the limestone slurry supply reference amount is directly output to realize the advance regulation when the load changes and avoid pH lag fluctuation.

[0043] The secondary loop is an equivalent pH feedback correction adjustment: real-time equivalent pH value and pH setpoint are collected, the deviation is calculated and the correction adjustment amount is output through PID algorithm, and the final control signal is output after being superimposed with the feedforward reference amount.

[0044] Actuator adjustment: When the real-time equivalent pH is greater than the set value, the slurry supply rate of limestone slurry pump 21 is reduced; when the real-time equivalent pH is less than the set value, the slurry supply rate is increased; when the real-time equivalent pH is equal to the set value, the current slurry supply rate is maintained. The system supports seamless manual / automatic switching, with no impact or fluctuation during the switching process.

[0045] Step 4: Fully Automatic High and Low Limit Protection and Interlocking When pH < 5.0, the interlock increases the slurry supply of limestone slurry pump 21, locks the gypsum slurry delivery pump 17, and issues an alarm to prevent absorption failure and deterioration of gypsum quality.

[0046] When pH > 6.0, the interlock reduces the slurry supply of limestone slurry pump 21, strengthens circulation and oxidation, and starts automatic flushing to prevent limestone passivation and system scaling and blockage.

[0047] The system synchronously operates the oxidation fan and gypsum slurry delivery pump 17 to ensure sufficient oxidation and stable crystallization.

[0048] Step 5: Automatic pH electrode flushing control Flushing Trigger: The industrial water flushing solenoid valve 4 supports timed flushing, manual flushing, and intelligent condition-triggered flushing. The timed flushing cycle is adjustable from 1 to 12 hours. The intelligent triggering conditions are: electrode slope < 90%, pH remains constant for ≥ 10 minutes, and pH change > 0.5 pH / 5 minutes. When any of the above triggering conditions are met, the DCS system sets the flushing request flag and starts the sequential control program.

[0049] Flushing sequence: The DCS sequential control program executes the following steps: Standby, awaiting flushing request; Open the drain solenoid valve 7; A 3-second delay is required to ensure unobstructed drainage channels. Open the industrial water flushing solenoid valve 4 to start the flushing timer. The flushing time for a single flush is adjustable from 10 to 120 seconds. When the flushing timer expires, close the industrial water flushing solenoid valve 4. After a 5-second delay, drain the remaining flushing water from the flow-through tank. Close the drain solenoid valve 7; When the feedback of the waste solenoid valve 7 is not open, the industrial water flushing solenoid valve 4 must not be opened; If the flushing time exceeds 120 seconds, the industrial water flushing solenoid valve 4 and the drain solenoid valve 7 will be forcibly closed, and an alarm will be triggered. When circulating slurry pump 2 stops or the desulfurization system trips, the flushing procedure is interrupted.

[0050] Step Six: Multi-Objective Optimization Execution The system aims to achieve a desulfurization efficiency of ≥95%, gypsum purity of ≥90%, and residual CaCO3 in the slurry of <3%, and automatically adjusts control parameters. The system prioritizes stabilizing the pH within the optimal range of 5.4–5.6, improving gypsum purity and reducing limestone consumption while ensuring desulfurization efficiency meets targets, thus achieving long-term, efficient, economical, and stable operation.

[0051] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A pH electrode rinsing device, characterized in that, include: The system includes an industrial water flushing solenoid valve, an industrial water inlet manual valve, a check valve, an industrial water flushing pipeline filter, a sewage discharge manual valve, a sewage discharge solenoid valve, an electrode flow tank, a pH electrode, a liquid inlet manual valve, a liquid inlet electric valve, an annular flushing opening pipe, and multiple sets of flushing nozzles. The industrial water flushing pipeline filter, check valve, industrial water inlet manual valve, and industrial flushing solenoid valve are connected in sequence. The upper part of the electrode flow tank is provided with an annular flushing opening pipe that extends obliquely into the electrode flow tank. Multiple sets of flushing nozzles are provided on the annular flushing opening pipe. The annular flushing opening pipe is connected to the industrial water flushing solenoid valve. A liquid inlet pipe is provided on one side of the lower part of the electrode flow tank. A sewage discharge pipe is provided at the lower part of the electrode flow tank. The bottom of the sewage discharge pipe is connected to the side wall of the top of the electrode flow tank through the flow tank overflow pipe. A pH electrode is provided at the top center of the electrode flow tank.

2. The pH electrode rinsing device according to claim 1, characterized in that, The liquid inlet pipeline includes a manual liquid inlet valve and a power liquid inlet valve, which are sequentially connected to the electrode flow cell.

3. The pH electrode rinsing device according to claim 2, characterized in that, The sewage discharge pipeline includes a manual sewage discharge valve and a solenoid sewage discharge valve. One end of the manual sewage discharge valve is connected to the electrode flow tank, and the other end of the manual sewage discharge valve is connected to the solenoid sewage discharge valve. The solenoid sewage discharge valve is also connected to the sewage overflow pipe and the sewage tank.

4. The pH electrode rinsing device according to claim 3, characterized in that, The diameter of the rinsing nozzle is 1-3 mm, and the spray direction of the nozzle is at an angle of 30°-60° to the axis of the pH electrode.

5. The pH electrode rinsing device according to claim 4, characterized in that, The elevation of the overflow pipe (8) is ≥50mm higher than the top of the pH electrode sensitive membrane.

6. The pH electrode rinsing device according to claim 5, characterized in that, The sewage discharge solenoid valve, the liquid inlet electric valve, and the industrial water flushing solenoid valve are all electrically connected to the DCS system.

7. A desulfurization absorption tower system equipped with a pH electrode flushing device, characterized in that, include: The pH electrode flushing device and spray tower as described in any one of claims 1-6, wherein the spray tower is provided with, from top to bottom, a first spray layer, a second spray layer, a flue gas inlet channel, an oxidation blower, a limestone slurry supply pump, a circulating slurry pump, and a gypsum slurry delivery pump; the first spray layer is connected to external industrial water; the second spray layer is simultaneously connected to two circulating slurry pumps; both circulating slurry pumps are simultaneously connected to the spray tower; the inlet pipe of the pH electrode flushing device is connected to the connecting pipe between the second spray layer and the two circulating slurry pumps; a flue gas sulfur dioxide content monitoring device and a flue gas flow sensor are sequentially connected outward from the flue gas inlet channel; the oxidation blower is located below the flue gas inlet channel and is connected to the interior of the spray tower; a slurry density meter is located below the oxidation blower; the pH electrode flushing device is located below the slurry density meter; a limestone slurry supply pump is located below the pH electrode flushing device; and a gypsum slurry delivery pump is connected to the spray tower located directly opposite the limestone slurry supply pump.

8. A control method for a desulfurization absorption tower system equipped with a pH electrode flushing device, characterized in that, The desulfurization absorption tower system equipped with a pH electrode flushing device as described in claim 7 includes: The pH values ​​at the two pH electrode flushing devices are obtained. After the measurement drift caused by the temperature compensation module is eliminated, the pH values ​​are entered into the signal processing unit for weighted average filtering to remove instantaneous interference, jump values ​​and deviations caused by slurry unevenness. The real-time equivalent pH value is output as the sole basis for system control. pH setting control logic: minimum pH protection value 5.0, maximum protection value 6.0; the system reads the SO2 concentration signal at the CEMS inlet in real time and automatically generates the pH setting value according to the following rules: pH value is set to 5.3 when SO2 concentration < 800 mg / m³; pH value is set to 5.5 when SO2 concentration is 800-1500 mg / m³; pH value is set to 5.7 when SO2 concentration > 1500 mg / m³. Collect the inlet flue gas flow rate and CEMS inlet SO2 concentration, calculate the total SO2 = flue gas flow rate × SO2 concentration, and directly output the limestone slurry supply benchmark quantity. The system collects the real-time equivalent pH value and the pH setpoint, calculates the deviation, and outputs the correction adjustment amount through the PID algorithm. The final control signal is then output after being superimposed with the feedforward reference amount. When the real-time equivalent pH is greater than the set value, reduce the slurry supply rate; when the real-time equivalent pH is less than the set value, increase the slurry supply rate; when the real-time equivalent pH is equal to the set value, maintain the current slurry supply rate. When pH < 5.0, the interlock increases limestone slurry supply, shuts off the gypsum discharge pump, and issues an alarm; when pH > 6.0, the interlock decreases limestone slurry supply, strengthens circulation and oxidation, and activates automatic flushing. It also includes an automatic pH electrode rinsing control process, including: Intelligent rinsing is triggered when the electrode slope is <90%, the pH remains constant for ≥10 min, or the pH change is >0.5 pH / 5 min. First, open the drain solenoid valve, and then open the industrial water flushing solenoid valve after a 3-second delay. After rinsing is complete, first close the rinsing solenoid valve, then close the drain solenoid valve after a 5-second delay. When the industrial water pressure is <0.2MPa, flushing is locked, flushing is prohibited, and an alarm will sound. Do not open the flushing solenoid valve if the sewage discharge solenoid valve has not provided feedback. If the flushing time exceeds 120 seconds, the flushing solenoid valve and the drain solenoid valve will be forcibly closed and an alarm will be triggered. The flushing process is interrupted when the circulating pump stops or the desulfurization system trips.

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