Desulfurization system cooperative control method and device for slurry pH dynamic feedback

Abstract

The invention relates to the technical field of flue gas desulfurization of a thermal power plant, and discloses a desulfurization system cooperative control method for slurry pH dynamic feedback, which comprises the following steps: S1, collecting parameters including desulfurization tower slurry pH values respectively marked as pH1 and pH2, slurry temperature T, slurry density rho, unit real-time load P, load change rate dP / dt, inlet SO2 concentration Cin, outlet SO2 concentration Cout, flue gas amount Q and slurry supply pump flow F, the pH 1 is used for collecting the pH value of a spraying area at the upper part of the desulfurization tower, and the pH 2 is used for collecting the pH value of a precipitation area at the lower part of the desulfurization tower; and S2, accurately correcting and fusing the pH value of the slurry. Through data fusion of sampling, filtering, temperature and the like, deviation caused by slurry layering, temperature fluctuation and suspended matter attachment in traditional single-point measurement is effectively overcome, and the overall chemical state of the slurry in the desulfurization tower can be truly and accurately reflected.

Description

Technical Field

[0001] This invention relates to the field of flue gas desulfurization technology in thermal power plants, specifically to a collaborative control method and device for a desulfurization system with dynamic pH feedback of slurry. Background Technology

[0002] Limestone-gypsum wet desulfurization is currently the mainstream desulfurization technology in thermal power plants. Its core principle is that limestone slurry (pH usually controlled at 5.5-6.0) in the desulfurization tower absorbs SO2 in the flue gas, generating calcium sulfite, which is then oxidized to gypsum. In this process, the pH value of the slurry is a key parameter determining the SO2 absorption efficiency. However, unit load fluctuations (such as frequent load changes and peak shaving of thermal power units due to the grid connection of new energy sources) will directly cause drastic changes in flue gas volume and SO2 concentration, thereby disrupting the dynamic balance of the desulfurization system. Existing technology has the following core defects: 1. Insufficient pH measurement accuracy: Traditional methods usually use single-point sampling in conjunction with ordinary pH probes for measurement, which does not fully consider the effects of uneven distribution of slurry in the tower, temperature changes, and solid particle adhesion, making it difficult for the measurement results to truly reflect the overall chemical state of the slurry.

[0003] 2. Insufficient coordinated control capability of the system under wide load conditions: Existing control strategies mostly rely on single variable adjustment, such as adjusting the slurry supply based solely on pH measurement values, without effectively coordinating with the operating status of other key equipment in the system. For example, when the unit load rises rapidly, if the circulating pump fails to adjust its operating status in time, even if the slurry supply is increased, the desulfurization efficiency may still decrease due to insufficient gas-liquid mass transfer; when the load decreases, if the slurry supply is not reduced accordingly, the slurry pH may be too high, affecting the economic efficiency of system operation.

[0004] 3. There is a contradiction between system energy consumption and operational stability. In order to adapt to load fluctuations, some existing technologies adopt a fixed high-load operation mode or frequently start and stop equipment, which not only leads to high energy consumption, but also easily causes frequent fluctuations in system operating conditions, affecting the stability of desulfurization effect. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for coordinated control of a desulfurization system with dynamic pH feedback of slurry, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for coordinated control of a desulfurization system based on dynamic pH feedback of slurry, comprising the following steps: S1. Collected parameters include the pH value of the desulfurization tower slurry, denoted as pH1 and pH2 respectively, slurry temperature T, slurry density ρ, real-time unit load P, load change rate dP / dt, and inlet SO2 concentration C. in SO2 concentration at the outlet Cout Flue gas volume Q, slurry pump flow rate F, circulating pump speed n, where pH1 is used to collect the pH value of the upper spray area of ​​the desulfurization tower, and pH2 is used to collect the pH value of the lower sedimentation area of ​​the desulfurization tower. S2. Precisely correct and blend the pH value of the slurry; S3. Based on the load change rate dP / dt, the operating conditions are divided into stable operating conditions and fluctuating operating conditions, and corresponding controls are executed. S4. The outlet SO2 concentration C is recorded every 5 seconds. out Feedback is sent to the control unit, which adjusts the slurry supply and circulation pump speed according to preset conditions.

[0007] As a preferred embodiment of the present invention, the specific steps of step S2 are as follows: S21. Filtration pretreatment: Filtering slurry suspension through a ceramic filter element; S22. Temperature correction: Based on the preset temperature-pH correction curve, perform temperature compensation on pH1 and pH2 to obtain pH1′ and pH2′. S23. Suspended solids correction: Based on the pH correction coefficient, perform suspended solids compensation on pH1′ and pH2′ to obtain pH1″ and pH2″. S24. Multi-point fusion: The final corrected pH value is calculated using a weighted average algorithm, i.e., pH. final =0.25×pH1″+0.5×pH2″.

[0008] As a preferred technical solution of the present invention, the temperature correction adopts a temperature-pH correction curve calibrated in the laboratory, and within the range of 20℃ to 60℃, each 1℃ corresponds to a pH correction value of ±0.02.

[0009] As a preferred embodiment of the present invention, in step S3, the stable operating condition is dP / dt ≤ 1% / min. Under the stable operating condition: when pH final <pH set At -0.1, the slurry pump flow rate F increases by ΔF, where ΔF = 5% × F_current, with a step size ≤ 2% / cycle, when pH final >pH set When the value is +0.1, the flow rate F of the slurry pump decreases by ΔF, while the speed n of the circulating pump remains at its current value. The fluctuating operating condition is defined as dP / dt > 1% / min. This fluctuating operating condition includes both increasing and decreasing load conditions. Under the increasing load fluctuating condition: when pH... final <pH set When -0.1 and dP / dt > 1% / min, the slurry supply rate F increases by ΔF × 1.2, and the circulating pump speed n increases by Δn; when pH final ≥pH setWhen -0.1 and dP / dt > 1% / min, the circulating pump speed n is increased synchronously while the slurry supply remains unchanged.

[0010] Under load reduction and fluctuation conditions: when pH final >pH set When +0.1 and dP / dt < -1% / min, the slurry supply F decreases by ΔF×1.2, and the circulating pump speed n decreases by Δn; when pH final ≤pH set When +0.1 and dP / dt < -1% / min, the circulating pump speed n is reduced synchronously while the slurry supply remains unchanged.

[0011] As a preferred embodiment of the present invention, the adjustment in step S4 specifically includes: when the outlet SO2 concentration C out >30mg / m 3 At that time, an additional 5% ΔF will be added to the current slurry supply, and the circulation pump speed will be increased by 2% Δn.

[0012] As a preferred embodiment of the present invention, the step S1 and step S2 further include: S2a. By collecting the slurry density ρ and suspended solids concentration C in real time, the rheological characteristics of the slurry are dynamically identified, and the response priority of the subsequent control strategy is adjusted adaptively: when the slurry tends to have high density and high concentration non-Newtonian fluid characteristics, the speed of the circulating pump is increased and the response amplitude of the slurry flow rate adjustment is reduced simultaneously. S2b. Based on the coupling relationship between the real-time load P of the unit and the load change rate dP / dt, predict the SO2 absorption load trend in the short term, and fine-tune the slurry chemical environment in advance before the actual flue gas parameters change. The fine-tuning of the slurry chemical environment in advance includes introducing auxiliary buffers in advance or adjusting the oxidation wind distribution mode. S2c, based on the outlet SO2 concentration C out Dynamically correct pH based on instantaneous gradient changes. set The temporary target interval, when C out When the pH shows an accelerating upward trend within a continuous sampling period, temporarily lower the pH. set Lower limit; when C out During accelerated decline, pH temporarily increases. set Upper limit.

[0013] A desulfurization system collaborative control device with dynamic pH feedback for slurry includes: The data acquisition unit includes a unit load sensor, a flue gas SO2 analyzer, a flue gas flow meter, and a slurry density sensor, which are used to collect unit load, flue gas parameters, and slurry density in real time. The pH precision measurement unit includes two sets of pH sampling components, each set containing a ceramic filter module, a temperature-compensated pH probe and a temperature sensor, as well as a pH correction module, used to complete slurry filtration, temperature and suspended solids correction and multi-point pH fusion. The collaborative control unit includes an edge computing PLC, a human-machine interface, and a data storage module, and has built-in pH correction fusion algorithm, wide load condition identification algorithm, and slurry supply-frequency conversion collaborative control algorithm; The execution unit includes a slurry supply regulating valve and a variable frequency circulating pump, which are used to receive control commands and adjust the slurry supply and the speed of the circulating pump.

[0014] As a preferred technical solution of the present invention, the pH sampling component is actually measured by performing pH measurement in an open flow cell outside the tower.

[0015] In a preferred embodiment of the present invention, the collaborative control unit communicates in real time with the data acquisition unit, the pH precision measurement unit, and the execution unit via an industrial Ethernet network; in the execution unit, the flow rate range of the slurry regulating valve is 0–100 m³ / s. 3 / h, the speed range of the variable frequency circulating pump is 0~1450r / min.

[0016] As a preferred embodiment of the present invention, the collaborative control unit is further connected to a predictive maintenance early warning module. The predictive maintenance early warning module performs the following tasks based on historical operating data and real-time equipment status: real-time monitoring of the bearing vibration amplitude and motor winding temperature of the variable frequency circulating pump; when the cumulative time of continuous over-limit operation of any parameter reaches a preset threshold, or when the parameter change trend conforms to a preset fault evolution model, an early warning signal is generated and maintenance suggestions are displayed on the human-machine interface.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. By integrating data such as sampling, filtration, and temperature, it effectively overcomes the deviations caused by slurry stratification, temperature fluctuations, and suspended matter adhesion in traditional single-point measurements, and can truly and accurately reflect the overall chemical state of the slurry in the desulfurization tower.

[0018] 2. By combining dynamic pH feedback with load change rate prediction, a multi-variable collaborative control strategy for slurry supply and circulation pumps was constructed, which solved the problems of lag in single-variable control response and mismatch between equipment actions under wide load conditions, and ensured the dynamic balance and stable operation of the system under severe load fluctuations.

[0019] 3. By dynamically adjusting the operating status of the frequency converter according to the actual working conditions, the high energy consumption and system oscillation caused by traditional full-load operation or frequent start-stop are avoided. While ensuring desulfurization efficiency, significant energy saving and consumption reduction are achieved.

[0020] 4. The system can automatically identify stable and fluctuating operating conditions and execute corresponding control logic, realizing fully automatic and adaptive optimized operation within a wide load range, reducing reliance on manual intervention, alleviating maintenance intensity, and improving overall reliability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall process of the method of the present invention; Figure 2 This is a schematic diagram of the structure and data flow of the pH precision measurement unit in this invention; Figure 3 This is a logical architecture diagram of the collaborative control unit in this invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1 Please see Figures 1 to 3 This invention provides a method for coordinated control of a desulfurization system based on dynamic pH feedback of slurry, comprising the following steps: S1. Collected parameters include the pH value of the desulfurization tower slurry, denoted as pH1 and pH2 respectively, slurry temperature T, slurry density ρ, real-time unit load P, load change rate dP / dt, and inlet SO2 concentration C. in SO2 concentration at the outlet C out Flue gas volume Q, slurry pump flow rate F, circulating pump speed n, where pH1 is used to collect the pH value of the upper spray area of ​​the desulfurization tower, and pH2 is used to collect the pH value of the lower sedimentation area of ​​the desulfurization tower. S2. Precisely correct and blend the pH value of the slurry; S3. Based on the load change rate dP / dt, the operating conditions are divided into stable operating conditions and fluctuating operating conditions, and corresponding controls are executed. S4. The outlet SO2 concentration C is recorded every 5 seconds. out Feedback is sent to the control unit, which adjusts the slurry supply and circulation pump speed according to preset conditions.

[0024] Furthermore, the specific steps of step S2 are as follows: S21. Filtration pretreatment: Filtering slurry suspension through a ceramic filter element; S22. Temperature Correction: Based on the preset temperature-pH correction curve, temperature compensation is applied to pH1 and pH2 to obtain pH1′ and pH2′. The principle of temperature correction is based on the theoretical relationship between the Nernst response of the pH electrode and the solution temperature, as well as the effect of temperature on pH in a specific limestone slurry system. + The actual impact of activity (i.e., apparent pH) is determined through the following implementation steps: 1. Laboratory calibration: In the laboratory, the chemical composition of the prepared slurry (such as limestone purity, Cl) is determined to match that used on-site. - Concentration, Mg 2+ A reference slurry sample with the same concentration, etc. 2. Data Acquisition: The reference slurry sample was placed in a constant temperature water bath, with the temperature varying in 5°C increments within the range of 20°C to 60°C (covering the operating temperature range of the desulfurization system). At each temperature point, the true pH value of the slurry was measured using a high-precision laboratory pH meter (with standard buffer temperature compensation). true Simultaneously, the pH readings of the same slurry sample on the temperature-compensated industrial pH probe used in this system are recorded. raw ); 3. Curve generation: For each temperature point T, calculate the temperature compensation value ΔpH for that point. temp（T） = pH true -pH raw A series of (T, ΔpH) temp The data points are fitted into a curve to obtain the preset temperature-pH correction curve. This curve is approximately linear in the range of 20℃ to 60℃. It has been verified that the pH correction value corresponding to each 1℃ is approximately ±0.02. 4. Field Application: The control unit calculates the compensation value ΔpH at the real-time slurry temperature T by querying or interpolating. temp（T） And compensate for the original measurement value: pH′ = pH raw +ΔpH temp（T） ; S23. Suspended solids correction: Based on the pH correction coefficient, suspended solids compensation is performed on pH1′ and pH2′ to obtain pH1″ and pH2″. The principle of suspended solids correction is to correct the measurement hysteresis and potential deviation caused by solid particles (mainly gypsum, unreacted limestone, and fly ash) adhering to the surface of the pH electrode sensing membrane. The specific implementation steps are as follows: 1. Establish a calibration coefficient table: In the laboratory or pilot plant, a series of suspended solids concentrations (C0) are prepared by adding inert simulated solids (such as fine silica sand) or changing the slurry stirring intensity. s The slurry sample (unit: wt%) was kept at a constant temperature and basic chemical composition. 2. Controlled measurement: For each different C sTwo sets of measurements were performed on the sample: a. After allowing the sample to settle, collect the supernatant and measure its pH using a high-precision laboratory pH meter. Record this pH as pH. clear (Consider it as the true chemical pH without interference from suspended matter).

[0025] b. Thoroughly stir the sample to maintain its suspension state, and directly use a flow cell equipped with a ceramic filter element of the same model as this system and an industrial pH probe to measure the pH value. measured .

[0026] 3. Coefficient Determination: Calculate each C s The suspended matter correction factor k (C) s pH clear - pH measured Therefore, the "suspended matter concentration C" was established. s —A lookup table or fitting formula for the correction coefficient k; in the actual system, the suspended solids concentration C s The slurry density ρ can be compared with the ρ-C established in the laboratory. s Obtained indirectly in real time through relational modeling.

[0027] 4. Field Application: The control unit calculates the slurry suspended solids concentration C based on real-time estimates. s Obtain the corresponding correction coefficient k, and perform secondary compensation on the pH value that has already undergone temperature correction: pH″ = pH′ + k (C s ); S24. Multi-point fusion: The final corrected pH value is calculated using a weighted average algorithm, i.e., pH. final =0.25×pH1″+0.5×pH2″. In this step, the weights of the weighted average algorithm are determined as follows: the sedimentation area at the bottom of the desulfurization tower (corresponding to the pH2 sampling point) is the core reaction zone for limestone dissolution and gypsum crystallization, and its pH value can better characterize the overall chemical buffer capacity and reaction process of the slurry, so it is given a higher weight (0.5); although the pH value of the upper spraying area (corresponding to the pH1 sampling point) is sensitive to load changes, it is easily affected by instantaneous fluctuations in gas-liquid mass transfer, so it is given a lower weight (0.25). This weight coefficient is determined by a combination of laboratory slurry homogenization control experiments and regression analysis of historical data from the field, which can ensure that the pH value of the fused slurry is within the range of 0.25. final The value is closest to the true average pH after the slurry is fully mixed, thus providing a more reliable and stable key parameter for synergistic control.

[0028] Furthermore, the temperature calibration uses a laboratory-calibrated temperature-pH calibration curve, with a pH calibration value of ±0.02 for every 1℃ within the range of 20℃ to 60℃.

[0029] Furthermore, in step S3, the steady-state condition is dP / dt ≤ 1% / min. Under the steady-state condition: when pH final <pH set At -0.1, the slurry pump flow rate F increases by ΔF, where ΔF = 5% × F_current, with a step size ≤ 2% / cycle, when pH final >pH set When the value is +0.1, the flow rate F of the slurry pump decreases by ΔF, while the speed n of the circulating pump remains at its current value. Fluctuating operating conditions are defined as dP / dt > 1% / min. These fluctuating operating conditions include both increasing and decreasing load conditions. Under increasing load fluctuating conditions: when pH... final <pH set When -0.1 and dP / dt > 1% / min, the slurry supply rate F increases by ΔF × 1.2, and the circulating pump speed n increases by Δn; when pH final ≥pH set When -0.1 and dP / dt > 1% / min, the circulating pump speed n is increased synchronously while the slurry supply remains unchanged.

[0030] Under load reduction and fluctuation conditions: when pH final >pH set When +0.1 and dP / dt < -1% / min, the slurry supply F decreases by ΔF×1.2, and the circulating pump speed n decreases by Δn; when pH final ≤pH set When +0.1 and dP / dt < -1% / min, the circulating pump speed n is reduced synchronously while the slurry supply remains unchanged.

[0031] Furthermore, the adjustment in step S4 specifically includes: when the outlet SO2 concentration C out >30mg / m 3 At that time, an additional 5% ΔF will be added to the current slurry supply, and the circulation pump speed will be increased by 2% Δn.

[0032] Furthermore, the interval between steps S1 and S2 also includes: S2a. By collecting the slurry density ρ in real time, the rheological characteristics of the slurry are dynamically identified, and the response priority of the subsequent control strategy is adjusted adaptively: when the slurry tends to have high density and high concentration non-Newtonian fluid characteristics, the speed of the circulating pump is increased and the response amplitude of the slurry flow rate adjustment is reduced simultaneously. S2b. Based on the coupling relationship between the real-time load P of the unit and the load change rate dP / dt, predict the SO2 absorption load trend in the short term, and fine-tune the slurry chemical environment in advance before the actual flue gas parameters change. The fine-tuning of the slurry chemical environment in advance includes introducing auxiliary buffers in advance or adjusting the oxidation wind distribution mode. S2c, based on the outlet SO2 concentration C out Dynamically correct pH based on instantaneous gradient changes.set The temporary target interval, when C out When the pH shows an accelerating upward trend within a continuous sampling period, temporarily lower the pH. set Lower limit; when C out During accelerated decline, pH temporarily increases. set Upper limit.

[0033] A desulfurization system collaborative control device with dynamic pH feedback for slurry includes: The data acquisition unit includes a unit load sensor, a flue gas SO2 analyzer, a flue gas flow meter, and a slurry density sensor, which are used to collect unit load, flue gas parameters, and slurry density in real time. The pH precision measurement unit includes two sets of pH sampling components, each set containing a ceramic filter module, a temperature-compensated pH probe and a temperature sensor, as well as a pH correction module, used to complete slurry filtration, temperature and suspended solids correction and multi-point pH fusion. The collaborative control unit includes an edge computing PLC, a human-machine interface, and a data storage module, and has built-in pH correction fusion algorithm, wide load condition identification algorithm, and slurry supply-frequency conversion collaborative control algorithm; The execution unit includes a slurry supply regulating valve and a variable frequency circulating pump, which are used to receive control commands and adjust the slurry supply and the speed of the circulating pump.

[0034] Furthermore, the pH sampling component is actually measured using an open flow cell outside the tower.

[0035] Furthermore, the collaborative control unit communicates in real time with the data acquisition unit, pH precision measurement unit, and execution unit via industrial Ethernet; within the execution unit, the flow rate range of the slurry supply regulating valve is 0–100 m³ / s. 3 / h, the speed range of the variable frequency circulating pump is 0~1450r / min.

[0036] Furthermore, the collaborative control unit is also connected to a predictive maintenance early warning module. Based on historical operating data and real-time equipment status, the predictive maintenance early warning module performs the following tasks: real-time monitoring of the bearing vibration amplitude and motor winding temperature of the variable frequency circulating pump; when the cumulative time of continuous operation exceeding the limit of any parameter reaches a preset threshold, or when the parameter change trend conforms to the preset fault evolution model, an early warning signal is generated and maintenance suggestions are displayed on the human-machine interface.

[0037] Example 2 In this embodiment, the same collaborative control method and device as in Embodiment 1 are used for industrial application in the desulfurization system of a 660MW coal-fired power unit. The flue gas volume of this system under rated load is approximately 2,200,000 m³ / h. 3 The implementation period is 3 months, during which the unit load fluctuates frequently within the range of 30% to 100%.

[0038] Key points of the implementation process: 1. Data Acquisition and pH Correction: The system continuously collects the pH value, temperature, and density of the open flow tank outside the tower, and performs real-time compensation and data fusion based on the preset temperature-pH correction curve to obtain a high-precision pH value. final value.

[0039] 2. Operating Condition Identification and Coordinated Control: The control system automatically identifies stable and fluctuating operating conditions based on the real-time calculated load change rate (dP / dt). Under fluctuating operating conditions, the system coordinates the flow rate (F) of the slurry pump and the speed (n) of the circulating pump according to preset logic.

[0040] 3. Dynamic feedback: The system detects the outlet SO2 concentration (C) every 5 seconds. out When C out >30 mg / m 3 At that time, the automatic adjustment mechanism is triggered, which increases the slurry supply by an additional 5% ΔF on the basis of the existing slurry supply, and simultaneously increases the circulation pump speed by 2% Δn.

[0041] Comparison Example To compare the effects, a desulfurization system with similar parameters to the unit and still using the traditional single-point pH measurement and single-variable slurry supply control strategy was selected as a control example. This control system only adjusts the slurry supply in one direction when the pH value is detected to deviate from the set value by more than the threshold. The speed of the circulating pump is kept fixed or adjusted by human experience.

[0042] Experimental data The key operational data from the three-month comparative test are shown in the table below: Performance indicators Embodiment 2 of the present invention Comparison Example Average deviation of pH measurement ±0.08 ±0.25 Fluctuation range of desulfurization efficiency under wide load (30%-100%) 95.5％～98.2％ 90％～96％ <![CDATA[Outlet SO2 concentration exceeds the standard (> 30mg / m 3 ), proportion of time]]> ＜0.5％ 3.5％ Average plant power consumption rate (desulfurization system) Reduced by approximately 12% benchmark Chemical stability of slurry (visual / sensory) Good, no significant stratification Occasionally, slurry stratification occurs. Experimental instructions 1. Regarding pH measurement accuracy: This invention significantly improves the accuracy of pH measurement through multi-point sampling, temperature correction, and data fusion. The average deviation is controlled at ±0.08, which is much lower than ±0.25 in the control example. This lays a reliable data foundation for subsequent precise control.

[0043] 2. Regarding desulfurization efficiency and stability: Under wide load fluctuation conditions, the system of this invention ensures that the desulfurization efficiency remains stable at a high level (95.5% to 98.2%) through dual-drive coordinated control of dynamic pH feedback and load change rate prediction, and the fluctuation range is much smaller than that of the control example. This shows that the present invention can effectively cope with the impact of load changes and maintain the dynamic balance of the system.

[0044] 3. Regarding emission compliance: The SO2 concentration at the outlet of the system of this invention exceeded the standard for less than 0.5% of the time, while the control example was 3.5%, which proves that the dynamic feedback adjustment mechanism of this invention can correct operational deviations more quickly and effectively and ensure continuous compliance with emission standards.

[0045] 4. Regarding the system operating status: In Example 2, the chemical state of the slurry was stable with no significant stratification. This was due to the precise pH control and the coordinated regulation of the circulating pump, which enhanced the gas-liquid mass transfer effect and maintained the homogeneity and reactivity of the slurry. In contrast, the control example showed occasional stratification due to control lag and poor coordination, which affected the reaction efficiency.

[0046] Experimental data fully demonstrate that the collaborative control method and device for wide-load desulfurization systems based on dynamic feedback of slurry pH described in this invention exhibits significant advantages over traditional control strategies in terms of measurement accuracy, desulfurization efficiency stability, emission compliance, energy consumption reduction, and system operation stability, effectively solving the challenges faced by desulfurization systems under wide-load conditions.

[0047] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for coordinated control of a desulfurization system with dynamic pH feedback of slurry, characterized in that, Includes the following steps: S1. Collected parameters include the pH value of the desulfurization tower slurry, denoted as pH1 and pH2 respectively, slurry temperature T, slurry density ρ, real-time unit load P, load change rate dP / dt, and inlet SO2 concentration C. in SO2 concentration at the outlet C out Flue gas volume Q, slurry pump flow rate F, circulating pump speed n, where pH1 is used to collect the pH value of the upper spray area of ​​the desulfurization tower, and pH2 is used to collect the pH value of the lower sedimentation area of ​​the desulfurization tower. S2. Precisely correct and blend the pH value of the slurry; S3. Based on the load change rate dP / dt, the operating conditions are divided into stable operating conditions and fluctuating operating conditions, and corresponding controls are executed. S4. The outlet SO2 concentration C is recorded every 5 seconds. out Feedback is sent to the control unit, which adjusts the slurry supply and circulation pump speed according to preset conditions.

2. The method for coordinated control of a desulfurization system with dynamic pH feedback of slurry according to claim 1, characterized in that, The specific steps of step S2 are as follows: S21. Filtration pretreatment: Filtering slurry suspension through a ceramic filter element; S22. Temperature correction: Based on the preset temperature-pH correction curve, perform temperature compensation on pH1 and pH2 to obtain pH1′ and pH2′. S23. Suspended solids correction: Based on the pH correction coefficient, perform suspended solids compensation on pH1′ and pH2′ to obtain pH1″ and pH2″. S24. Multi-point fusion: The final corrected pH value is calculated using a weighted average algorithm, i.e., pH. final =0.25×pH1″+0.5×pH2″.

3. The method for coordinated control of a desulfurization system with dynamic pH feedback of slurry according to claim 2, characterized in that, The temperature correction uses a laboratory-calibrated temperature-pH correction curve, with a pH correction value of ±0.02 for every 1℃ within the range of 20℃ to 60℃.

4. The method for coordinated control of a desulfurization system with dynamic pH feedback of slurry according to claim 1, characterized in that, In step S3, the stable operating condition is dP / dt ≤ 1% / min. Under the stable operating condition, when pH final <pH set At -0.1, the slurry pump flow rate F increases by ΔF, where ΔF = 5% × F_current, with a step size ≤ 2% / cycle, when pH final >pH set When the value is +0.1, the flow rate F of the slurry pump decreases by ΔF, while the speed n of the circulating pump remains at its current value. The fluctuating operating condition is defined as dP / dt > 1% / min. This fluctuating operating condition includes both increasing and decreasing load conditions. Under the increasing load fluctuating condition: when pH... final <pH set When -0.1 and dP / dt > 1% / min, the slurry supply rate F increases by ΔF × 1.2, and the circulating pump speed n increases by Δn; when pH final ≥pH set When -0.1 and dP / dt > 1% / min, the circulating pump speed n is increased synchronously while the slurry supply remains unchanged; Under load reduction and fluctuation conditions: when pH final >pH set When +0.1 and dP / dt < -1% / min, the slurry supply F decreases by ΔF×1.2, and the circulating pump speed n decreases by Δn; when pH final ≤pH set When +0.1 and dP / dt < -1% / min, the circulating pump speed n is reduced synchronously while the slurry supply remains unchanged.

5. The method for coordinated control of a desulfurization system with dynamic pH feedback of slurry according to claim 1, characterized in that, The adjustment in step S4 specifically includes: when the outlet SO2 concentration C out >30mg / m 3 At that time, an additional 5% ΔF will be added to the current slurry supply, and the circulation pump speed will be increased by 2% Δn.

6. The method for coordinated control of a desulfurization system with dynamic pH feedback of slurry according to claim 1, characterized in that, The step between step S1 and step S2 also includes: S2a. By collecting the slurry density ρ in real time, the rheological characteristics of the slurry are dynamically identified, and the response priority of the subsequent control strategy is adjusted adaptively: when the slurry tends to have high density and high concentration non-Newtonian fluid characteristics, the speed of the circulating pump is increased and the response amplitude of the slurry flow rate adjustment is reduced simultaneously. S2b. Based on the coupling relationship between the real-time load P of the unit and the load change rate dP / dt, predict the SO2 absorption load trend in the short term, and fine-tune the slurry chemical environment in advance before the actual flue gas parameters change. The fine-tuning of the slurry chemical environment in advance includes introducing auxiliary buffers in advance or adjusting the oxidation wind distribution mode. S2c, based on the outlet SO2 concentration C out Dynamically correct pH based on instantaneous gradient changes. set The temporary target interval, when C out When the pH shows an accelerating upward trend within a continuous sampling period, temporarily lower the pH. set Lower limit; when C out During accelerated decline, pH temporarily increases. set Upper limit.

7. A collaborative control device for a desulfurization system with dynamic pH feedback of slurry, characterized in that, include: The data acquisition unit includes a unit load sensor, a flue gas SO2 analyzer, a flue gas flow meter, and a slurry density sensor, which are used to collect unit load, flue gas parameters, and slurry density in real time. The pH precision measurement unit includes two sets of pH sampling components, each set containing a ceramic filter module, a temperature-compensated pH probe and a temperature sensor, as well as a pH correction module, used to complete slurry filtration, temperature and suspended solids correction and multi-point pH fusion. The collaborative control unit includes an edge computing PLC, a human-machine interface, and a data storage module, and has built-in pH correction fusion algorithm, wide load condition identification algorithm, and slurry supply-frequency conversion collaborative control algorithm; The execution unit includes a slurry supply regulating valve and a variable frequency circulating pump, which are used to receive control commands and adjust the slurry supply and the speed of the circulating pump.

8. The desulfurization system collaborative control device with dynamic pH feedback of slurry according to claim 7, characterized in that, The pH sampling component is actually measured by performing pH measurement in an open flow cell outside the tower.

9. The desulfurization system collaborative control device with dynamic pH feedback of slurry according to claim 7, characterized in that, The collaborative control unit communicates in real time with the data acquisition unit, pH precision measurement unit, and execution unit via industrial Ethernet; in the execution unit, the slurry supply regulating valve regulates the slurry flow rate from 0 to 100 m³ / h. 3 / h, the speed range of the variable frequency circulating pump is 0~1450r / min.

10. The desulfurization system collaborative control device with dynamic pH feedback of slurry according to claim 7, characterized in that, The collaborative control unit is also connected to a predictive maintenance early warning module. The predictive maintenance early warning module performs the following tasks based on historical operating data and real-time equipment status: real-time monitoring of the bearing vibration amplitude and motor winding temperature of the variable frequency circulating pump; when the cumulative time of continuous operation exceeding the limit of any parameter reaches a preset threshold, or when the parameter change trend conforms to the preset fault evolution model, an early warning signal is generated and maintenance suggestions are displayed on the human-machine interface.

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