A circulating cooling water collaborative dosing and blowdown ratio closed-loop control method and system

Abstract

The present application relates to the technical field of industrial circulating cooling water treatment and intelligent control, and particularly relates to a circulating cooling water collaborative dosing and blowdown ratio closed-loop control method and system. The method first collects and pre-processes the water quality and operating parameters of circulating water and make-up water, and respectively constructs a scale risk evaluation model and a corrosion risk evaluation model that fuse multi-dimensional influence factors; then takes the double risk values, chemical agent consumption and blowdown volume as optimization variables, establishes a double-objective comprehensive optimization function with safety threshold constraints, and solves the optimal dosing and blowdown control parameters through an optimization algorithm; subsequently, a differentiated collaborative control strategy is executed according to the risk relative level to link and adjust the chemical agent dosing and blowdown ratio; finally, the model parameters are dynamically corrected through multi-time scale operation feedback data to form a complete closed-loop control. The present application can improve the concentration ratio, reduce chemical agent consumption and blowdown volume while ensuring equipment safety, thereby improving the safety, stability and economy of the overall operation of the circulating cooling water system.

Description

Technical Field

[0001] This invention relates to the field of industrial circulating cooling water treatment and intelligent control technology, specifically to a closed-loop control method and system for the coordinated dosing and sewage discharge ratio of circulating cooling water. Background Technology

[0002] Industrial circulating cooling water systems are core utilities in process industries such as steel, petrochemicals, and power generation. Their operating status directly affects the heat exchange efficiency and service life of production equipment. Currently, the chemical dosing and wastewater discharge control of circulating cooling water systems mostly adopt independent operation modes: chemical dosing is mostly based on timed and quantitative addition or proportional addition of a single water quality parameter, making it difficult to dynamically adjust the reagent ratio according to water quality fluctuations and load changes; wastewater discharge control is mostly based on fixed conductivity thresholds or fixed concentration ratios, without linkage with scaling, corrosion risks, and reagent dosing status.

[0003] Under the existing control model, scale control and corrosion control are prone to imbalance. The dosing of chemicals and the regulation of sewage discharge lack a global optimization mechanism. Moreover, once the model parameters are solidified, they are difficult to adapt to the drift of operating conditions. At the same time, microbial control is separated from scale and corrosion control, which can easily lead to secondary problems such as under-deposit corrosion and local scale, thus restricting the safety and economy of system operation. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a closed-loop control method and system for the coordinated addition of chemicals and the discharge ratio of circulating cooling water. By establishing a dual-objective evaluation model for scaling risk and corrosion risk, the system achieves closed-loop control of the coordinated addition of scale inhibitors, corrosion inhibitors, and bactericides and the dynamic adjustment of the discharge ratio, taking into account both the safety and economy of system operation.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: I. A closed-loop control method for coordinated chemical dosing and blowdown ratio of circulating cooling water This invention provides a closed-loop control method for the coordinated dosing and sludge discharge ratio of circulating cooling water, which mainly includes the following steps: S1, Monitoring data acquisition and preprocessing: Collect water quality parameters and operating parameters of the circulating water side and makeup water side of the circulating cooling water system, and perform outlier removal, filtering and calibration preprocessing on the raw data to obtain standardized monitoring data; S2, Establishment of scaling risk model: Calculate scaling risk value based on the standardized monitoring data and construct a scaling risk assessment model for the circulating cooling water system; S3, Corrosion Risk Model Establishment: Based on the standardized monitoring data, calculate the corrosion risk value and construct a corrosion risk assessment model for the circulating cooling water system; S4, Construction and solution of the dual-objective optimization function: Establish a dual-objective comprehensive optimization function for scaling risk and corrosion risk with constraints, and obtain the optimal control parameters by solving the optimization algorithm; S5, Closed-loop control of dosing and discharge ratio: Dosing and discharge ratio are adjusted in conjunction with the optimal control parameters. Differentiated collaborative control strategies are implemented based on the relative levels of scaling risk and corrosion risk to achieve linkage matching of scaling inhibition, corrosion protection and discharge control. S6, Dynamic Feedback Correction and Adjustment: Collect actual system operation feedback data and dynamically correct the weight parameters and optimization function weights of the scaling risk model and corrosion risk model to form a fully closed-loop control loop.

[0006] Preferably, in step S2, the scaling risk assessment model has the following expression:

[0007] In the formula: This represents the scaling risk value. The Langrillly saturation index; This refers to the concentration of dissolved silicon in the circulating water. This refers to the calcium ion concentration in the circulating water. This is a concentration ratio correction factor; , , , These are the model weight coefficients for each parameter; The fouling risk assessment model can be further improved by introducing one or more of the following: temperature correction term, flow rate correction term, and local heat transfer surface heat flux correction term, in order to enhance the model's adaptability to the actual fouling trend of heat exchangers.

[0008] Preferably, in step S3, the corrosion risk assessment model has the following expression:

[0009] In the formula: This represents the corrosion risk value. This refers to the chloride ion concentration in the circulating water. This refers to the sulfate concentration in the circulating water. Dissolved oxygen concentration; This represents the deviation of the current pH value from the center value of the set corrosion control range. Temperature-related factors; , , , , These are the model weight coefficients for each parameter; Wherein, the model weight coefficients , , , , The selection is made in real time based on the main material of the circulating water pipeline on site, in order to adapt to the metal corrosion mechanism of different pipeline materials.

[0010] Furthermore, when At mg / L, a high-chlorine enhancement weighting correction factor is introduced into the chloride ion term. This modifies the corrosion risk model expression to:

[0011] in .

[0012] Preferably, in step S4, the dual-objective comprehensive optimization function for scaling risk and corrosion risk is:

[0013] In the formula, To comprehensively optimize the objective function; This represents the scaling risk value. This represents the corrosion risk value. The cost of drug consumption per unit time or the total amount of drug consumed; This refers to the amount of sewage discharged per unit time. , , , These are the weighting coefficients for each item; The optimization constraints include:

[0014]

[0015] In the formula, This is the corrosion safety threshold; This represents the allowable threshold for scaling.

[0016] Specifically, the optimization algorithm can be any one of linear programming, nonlinear programming, genetic algorithm, particle swarm optimization, or model predictive control algorithm to perform the optimization solution; the optimal control parameters include: scale inhibitor dosage, corrosion inhibitor dosage, bactericide dosage frequency and dosage cycle, sewage discharge ratio and sewage discharge valve adjustment parameters, and target concentration ratio.

[0017] Preferably, in step S5, the closed-loop control of the dosage and discharge ratio includes: 1) When the scaling risk Rs increases while the corrosion risk Rc is low, prioritize increasing the dosage of scale inhibitor, maintain or slightly adjust the blowdown ratio, so that the system can suppress the scaling trend without significantly increasing the corrosion risk. 2) When the corrosion risk Rc increases while the scaling risk Rs is controllable, prioritize increasing the discharge volume, reducing the concentration ratio, and simultaneously increasing the dosage of corrosion inhibitor to rapidly reduce the enrichment of corrosive ions. 3) When both scaling risk Rs and corrosion risk Rc increase simultaneously, prioritize ensuring that the corrosion risk meets the safety threshold requirements. On this basis, adjust the scale inhibitor, corrosion inhibitor, and blowdown ratio simultaneously. If necessary, reduce the system recovery rate or reduce the operating concentration ratio. 4) When the risk of microbial slime increases, adjust the frequency of bactericide shock dosing based on changes in redox potential, turbidity, pressure difference, and colony trends to avoid slime deposition inducing localized corrosion and under-deposit corrosion.

[0018] Preferably, in step S6, the actual operation feedback data of the system includes: the measured rate of corrosion of the coupons, the online iron ion concentration, the change in pressure drop at the inlet and outlet of the heat exchanger, the change in the heat transfer temperature difference of the heat exchanger, the pressure drop or blockage trend of the cooling tower packing, and the results of sediment thickness and composition analysis obtained during system shutdown and maintenance. The dynamic feedback correction adjustment includes: 1) When the measured corrosion rate of the corrosion coupon is higher than the corresponding value predicted by the model, increase the weight of the corrosion risk term. Or increase the weighting coefficients for chloride ions and dissolved oxygen; 2) When the pressure drop or heat transfer degradation of the heat exchanger exceeds the corresponding value predicted by the model, increase the weight of the scaling risk term. Or increase the coefficients of the correction terms for silica, calcium ions, and concentration ratio; 3) When drug consumption is high but risk indicators are stable, the weight of drug consumption items should be appropriately increased. This prompts the optimization algorithm to be modified towards lower drug consumption. 4) When the discharge volume is consistently high and there is sufficient capacity for corrosion and scaling, the weight of the discharge item should be appropriately increased. This will drive the system to operate at a higher concentration ratio.

[0019] II. A circulating cooling water control system Based on the same inventive concept, this invention also provides a circulating cooling water control system employing the closed-loop control method for coordinated dosing and sludge discharge ratio of circulating cooling water as described above, mainly comprising: 1) Online monitoring instrument unit, deployed in the circulating water main pipe, water supply main pipe and sewage pipe, is used to collect water quality parameters and operating parameters of the circulating cooling water system in real time, and to perform signal conversion and monitoring data preprocessing; 2) Scaling risk calculation module, used to receive pre-processed monitoring data and call the scaling risk model to calculate the real-time scaling risk value; 3) Corrosion risk calculation module, used to receive preprocessed monitoring data and call the corrosion risk model to calculate real-time corrosion risk value; 4) A dual-objective optimization module is used to construct a comprehensive optimization objective function based on scaling risk value, corrosion risk value, chemical consumption cost and sewage discharge volume, and solve for the current optimal control parameters; 5) Dosing control module, used to adjust the dosage and frequency of scale inhibitors, corrosion inhibitors and bactericides based on optimization results; 6) Sewage control module, used to dynamically adjust the system sewage discharge ratio and sewage valve opening based on optimization results, so as to control the system concentration ratio; 7) Feedback correction module, used to receive feedback signals such as the measured corrosion rate of the corrosion coupons, online iron ion concentration, and heat exchanger pressure drop changes, and to correct the model weight parameters and control thresholds; 8) Central control unit, used to realize data interaction between modules, issue control commands, display operating status and store historical data.

[0020] The dosing control module corresponds to multiple independent dosing pumps and chemical storage tanks, and can independently adjust the dosage of scale inhibitor, corrosion inhibitor, oxidizing bactericide and non-oxidizing bactericide; the sewage control module controls the sewage valve and water supply valve in conjunction, and adjusts the system concentration ratio while maintaining the cooling tower liquid level.

[0021] Compared with the prior art, the present invention has the following main advantages: 1. This invention considers both scaling and corrosion risks, establishes a dynamic coupling relationship between these risks and the dosage of chemicals and the discharge ratio, and adopts a constrained dual-objective optimization algorithm. Under the premise of meeting the safety thresholds for scaling and corrosion, it comprehensively optimizes the dosage of chemicals and the discharge ratio, dynamically explores the potential for increasing the system's concentration ratio, and achieves precise matching between chemical dosage and discharge adjustment. This can improve the concentration ratio and reduce chemical consumption and discharge volume while ensuring equipment safety, thereby improving the overall safety, stability and economy of the circulating cooling water system. 2. This invention combines on-site feedback information to construct a dynamic feedback correction mechanism, which can continuously calibrate model parameters and control thresholds based on actual on-site operating data and maintenance results. The control accuracy is continuously iterated and optimized with operation, adapting to changes in operating conditions such as water quality fluctuations, seasonal changes, and equipment aging. The entire system has complete closed-loop control logic, enabling unmanned intelligent operation, reducing the intensity of manual maintenance, and adapting to different industries and circulating cooling water system scenarios with different materials. Attached Figure Description

[0022] Figure 1 This is an overall flowchart of the control method in an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the principle of constructing and solving the bi-objective optimization function in an embodiment of the present invention; Figure 3This is a schematic diagram illustrating the closed-loop control of chemical dosage and sewage discharge ratio in an embodiment of the present invention. Figure 4 This is a schematic diagram illustrating the working principle of the feedback correction module in an embodiment of the present invention. Figure 5 This is a comparison chart of the optimization effects of the present invention compared to the traditional circulating water control method in the embodiments of the present invention; Figure 6 This is a schematic diagram of the overall circulating cooling water control system in an embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0024] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0025] In this invention, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

[0026] Example 1: This example provides a closed-loop control method for the coordinated dosing and blowdown ratio of circulating cooling water. The method first collects and preprocesses the water quality and operating parameters of the circulating water and makeup water, and then constructs a scaling risk assessment model and a corrosion risk assessment model that integrates multiple influencing factors. Next, using dual risk values, reagent consumption, and blowdown volume as optimization variables, a dual-objective comprehensive optimization function with safety threshold constraints is established. The optimal dosing and blowdown control parameters are then solved using an optimization algorithm. Subsequently, a differentiated coordinated control strategy is implemented based on the relative risk level, and the reagent dosing and blowdown ratios are adjusted in a coordinated manner. Finally, the model parameters are dynamically corrected using multi-timescale operational feedback data to form a complete closed-loop control. In this embodiment, the control method considers both scaling risk and corrosion risk, establishes a dynamic coupling relationship between the two and the dosage of the reagent and the discharge ratio, and combines on-site feedback information to form a closed-loop control that can be continuously corrected. This can improve the concentration ratio and reduce the consumption of reagents and the discharge volume while ensuring corrosion safety, thereby improving the overall safety, stability and economy of the circulating cooling water system.

[0027] like Figure 1 As shown, the control method mainly includes the following steps: Step S1, Monitoring data acquisition and preprocessing: Water quality parameters and system operating parameters on the circulating water side and the makeup water side are collected synchronously by online monitoring instruments. The raw data is preprocessed by filtering and noise reduction, and finally stored in the real-time database according to a unified timestamp to provide a stable data source for subsequent model calculations. The water quality parameters include pH, conductivity, chloride ions, sulfate ions, calcium ions, total alkalinity, dissolved oxygen, silica, redox potential, turbidity, and iron ions; the operating parameters include circulating water flow rate, makeup water flow rate, sewage discharge flow rate, inlet and outlet temperature difference and pressure drop of the heat exchanger, cooling tower liquid level, and pipe wall temperature.

[0028] Step S2, Establishment of scaling risk model: The scaling risk assessment model constructed in this invention has the following expression:

[0029] In the formula: This represents the scaling risk value. The Langrillly saturation index; This refers to the concentration of dissolved silicon in the circulating water. This refers to the calcium ion concentration in the circulating water. This is a concentration ratio correction factor; , , , These are the model weight coefficients for each parameter.

[0030] Wherein, the concentration ratio correction factor It is used to reflect the amplified scaling tendency under high concentration conditions and can be determined based on the ratio of conductivity of circulating water to makeup water, chloride ion ratio, or total dissolved solids ratio.

[0031] In this embodiment, the fouling risk model can be further modified by introducing temperature correction terms, flow rate correction terms, or local heat transfer surface heat flux correction terms to improve the model's adaptability to actual heat exchanger fouling trends.

[0032] Step S3, Corrosion Risk Model Establishment: The corrosion risk assessment model constructed in this invention has the following expression:

[0033] In the formula: This represents the corrosion risk value. This refers to the chloride ion concentration in the circulating water. This refers to the sulfate concentration in the circulating water. Dissolved oxygen concentration; This represents the deviation of the current pH value from the center value of the set corrosion control range. Temperature-related factors; , , , , These are the model weight coefficients for each parameter.

[0034] Furthermore, when At mg / L, a high-chlorine enhancement weighting correction factor is introduced into the chloride ion term. This modifies the corrosion risk model expression to:

[0035] in .

[0036] In this embodiment, the corrosion risk model can also introduce a material sensitivity coefficient based on the material of the circulating water pipeline. When the main material of the circulating water pipeline is carbon steel, low alloy steel or copper alloy, different weight combinations are used to adapt to different metal corrosion mechanisms.

[0037] Step S4: Construction and solution of the dual-objective optimization function for scaling risk and corrosion risk: like Figure 2 As shown, to achieve synergistic control of scaling and corrosion, this invention constructs a dual-objective optimization function for scaling risk and corrosion risk:

[0038] In the formula, To comprehensively optimize the objective function; This represents the scaling risk value. This represents the corrosion risk value. The cost of drug consumption per unit time or the total amount of drug consumed; This refers to the amount of sewage discharged per unit time. , , , These are the weighting coefficients for each item; The optimization constraints include:

[0039]

[0040] In the formula, This is the corrosion safety threshold; This represents the allowable threshold for scaling.

[0041] Furthermore, the dual-objective optimization module employs any one of linear programming, nonlinear programming, genetic algorithm, particle swarm optimization, or model predictive control algorithm to perform optimization and output the following optimal control variables: scale inhibitor dosage, corrosion inhibitor dosage, bactericide dosage frequency and dosage cycle, sewage discharge ratio and sewage valve adjustment parameters, and target concentration ratio.

[0042] Step S5, closed-loop control of chemical dosage and wastewater discharge ratio: like Figure 3 As shown, the closed-loop control of the dosage and discharge ratio of the present invention includes: 1) When the scaling risk Rs increases while the corrosion risk Rc is low, prioritize increasing the dosage of scale inhibitor, maintain or slightly adjust the blowdown ratio, so that the system can suppress the scaling trend without significantly increasing the corrosion risk. 2) When the corrosion risk Rc increases while the scaling risk Rs is controllable, prioritize increasing the discharge volume, reducing the concentration ratio, and simultaneously increasing the dosage of corrosion inhibitor to rapidly reduce the enrichment of corrosive ions. 3) When both scaling risk Rs and corrosion risk Rc increase simultaneously, prioritize ensuring that the corrosion risk meets the safety threshold requirements. On this basis, adjust the scale inhibitor, corrosion inhibitor, and blowdown ratio simultaneously. If necessary, reduce the system recovery rate or reduce the operating concentration ratio. 4) When the risk of microbial slime increases, adjust the frequency of bactericide shock dosing based on changes in redox potential, turbidity, pressure difference, and colony trends to avoid slime deposition inducing localized corrosion and under-deposit corrosion.

[0043] Step S6, Dynamic Feedback Correction and Adjustment: To enhance the consistency between the model and actual operating conditions, this invention introduces a feedback correction mechanism and establishes a hierarchical feedback correction mechanism. It continuously calibrates the model and control parameters using on-site measured data. The actual system operation feedback data collected includes: measured corrosion rate of the corrosion plates, online iron ion concentration, changes in pressure drop at the inlet and outlet of the heat exchanger, changes in the heat transfer temperature difference of the heat exchanger, pressure drop or blockage trend of the cooling tower packing, and sediment thickness and composition analysis results obtained during system shutdown and maintenance. like Figure 4 As shown, the feedback correction and adjustment strategy of the present invention includes: 1) When the measured corrosion rate of the corrosion coupon is higher than the corresponding value predicted by the model, increase the weight of the corrosion risk term. Or increase the weighting coefficients for chloride ions and dissolved oxygen; 2) When the pressure drop or heat transfer degradation of the heat exchanger exceeds the corresponding value predicted by the model, increase the weight of the scaling risk term. Or increase the coefficients of the correction terms for silica, calcium ions, and concentration ratio; 3) When drug consumption is high but risk indicators are stable, the weight of drug consumption items should be appropriately increased. This prompts the optimization algorithm to be modified towards lower drug consumption. 4) When the discharge volume is consistently high and there is sufficient capacity for corrosion and scaling, the weight of the discharge item should be appropriately increased. This will drive the system to operate at a higher concentration ratio.

[0044] Example 2: This example uses a circulating cooling water system of a steel company as an example. This circulating cooling water system uses a mixture of "urban greywater and RO permeate" as the makeup water source, with urban greywater accounting for 70% to 85% of the total makeup water. Due to the high chloride ion, hardness, alkalinity, and silica content in the greywater, the system faces the problem of increased scaling and corrosion risk when operating at a higher concentration ratio.

[0045] 1. System Basic Conditions This circulating cooling water system primarily serves production heat exchange equipment and process cooling units. The main body of the system is made of carbon steel, with some heat exchange surfaces made of stainless steel. The system is equipped with an online monitoring unit to collect the following parameters in real time: pH, conductivity, chloride ion concentration, total hardness, alkalinity, silica concentration, dissolved oxygen, water temperature, makeup water flow rate, circulation volume and wastewater discharge volume, and online iron ion concentration.

[0046] Typical raw water indicators are as follows:

[0047] 2. Operating mode before optimization Before adopting this invention, the system mainly used the traditional circulating water control method, namely: 1) Estimate scaling risk based on LSI and manually adjust scale inhibitor dosage; 2) The sewage discharge ratio has been fixed at 3.0 for a long period of time; 3) The dosage of corrosion inhibitor should be set based on empirical values; 4) Corrosion-resistant pads are only subject to periodic post-event inspections and are not involved in real-time control; 5) The bactericide should be added at a fixed interval.

[0048] Under the traditional circulating water control method, the system operating data is as follows:

[0049] Meanwhile, it was found on site that the heat exchanger's heat transfer performance fluctuated greatly, some carbon steel pipe sections showed obvious corrosion tendency, and the amount of wastewater discharged was high.

[0050] 3. Implementation process of the method of the present invention The specific steps for integrating the dual-target synergistic dosing and wastewater discharge ratio closed-loop control system of the present invention into the circulating cooling water system are as follows: Step 1: Real-time collection of water quality and operating parameters The key parameters of the circulating water are collected every 5 minutes by the online monitoring unit and uploaded to the central control unit.

[0051] Step 2: Calculate the scaling risk value Rs Calculate the scaling risk value based on the online collected LSI, silica concentration, calcium ion concentration, and concentration ratio correction factor. In this embodiment, the weighting coefficients are determined by calibrating historical operational data. , , , Take values ​​of 0.35, 0.20, 0.25, and 0.20 respectively.

[0052] Step 3: Calculate the corrosion risk value Rc Corrosion risk values ​​were calculated based on online data collected for chloride ions, sulfate ions, dissolved oxygen, pH deviation, and temperature factors. Considering that the system chloride ion concentration has been consistently above 500 mg / L, a high-chlorine correction factor is introduced into the chloride ion term. After fitting with historical data, , , , , Take values ​​of 0.30, 0.15, 0.20, 0.15, and 0.20 respectively.

[0053] Step 4: Establish and solve the comprehensive optimization objective function. Construct the following objective function:

[0054] Based on the company's requirements for equipment safety and water conservation, set , , , .

[0055] Simultaneously set: Corrosion safety threshold The corresponding corrosion rate of carbon steel is no higher than 0.06 mm / a; Scaling allowable threshold The corresponding rate of increase in scale thickness on the heat exchanger should not exceed 0.08 mm / month.

[0056] The optimization module performs a rolling calculation of the optimal control result every hour and outputs the scale inhibitor dosage, corrosion inhibitor dosage, bactericide dosing cycle, and sewage discharge ratio setpoint.

[0057] Step 5: Execute closed-loop control When the system detects that the evaporation rate and concentration ratio have increased due to the rise in temperature, if the risk of scaling increases while the risk of corrosion remains low, the system will prioritize increasing the dosage of scale inhibitor and keep the discharge ratio basically stable. When the system detects an increase in chloride ion levels in the makeup water, causing the corrosion risk to exceed the set threshold, it automatically increases the discharge volume, reduces the target concentration ratio, and simultaneously increases the amount of corrosion inhibitor added. When both types of risks increase simultaneously, the system prioritizes ensuring that the corrosion risk does not exceed the limit, and then controls the scaling trend by increasing the dosage of scale inhibitor and adjusting the concentration ratio.

[0058] Step 6: Feedback and Correction Corrosion testing of the fins was conducted every 30 days during operation, and the weights of the optimization model were adjusted based on changes in online iron ion concentration and heat exchanger pressure drop.

[0059] When the measured rate of the heat exchanger plate is higher than the model prediction at a certain stage, the corrosion risk weight is increased; when the pressure drop of the heat exchanger increases faster than the prediction, the scaling risk weight is increased.

[0060] 4. Optimized running results After running continuously for 8 months using the method of this invention, the main operating indicators of the system are as follows:

[0061] As can be seen from the above results: 1) With the corrosion rate decreasing from 0.12 mm / a to 0.05 mm / a, the system concentration ratio increased from 3.0 to 4.2; 2) The scale thickness of the heat exchanger decreased from 1.2 mm to 0.6 mm, indicating that scaling was significantly inhibited; 3) The consumption of scale inhibitor decreased from 5.6 mg / L to 4.2 mg / L, resulting in a significant reduction in agent consumption; 4) Annual sewage discharge decreased by 28%, demonstrating significant water conservation and emission reduction effects; 5) The overall system operation fluctuations are reduced, and the heat exchange efficiency is more stable.

[0062] In summary, this invention can achieve a balance between scaling and corrosion risks under urban wastewater replenishment conditions characterized by high chlorine, high hardness, and high silica, demonstrating excellent engineering application results.

[0063] like Figure 5As shown, compared with traditional circulating water control methods, this invention achieves dual-risk synergistic control by incorporating scaling risk, corrosion risk, chemical consumption, and sewage discharge into a unified optimization framework, which significantly improves the system's operational safety, stability, and economy.

[0064] Example 3: Based on the same inventive concept, this example also provides a circulating cooling water control system employing the closed-loop control method for coordinated dosing and sludge discharge ratio of circulating cooling water as described above, such as... Figure 6 As shown, it mainly includes: 1) Online monitoring instrument unit, deployed in the circulating water main pipe, water supply main pipe and sewage pipe, is used to collect water quality parameters and operating parameters of the circulating cooling water system in real time, and to perform signal conversion and monitoring data preprocessing; 2) Scaling risk calculation module, used to receive pre-processed monitoring data and call the scaling risk model to calculate the real-time scaling risk value; 3) Corrosion risk calculation module, used to receive preprocessed monitoring data and call the corrosion risk model to calculate real-time corrosion risk value; 4) A dual-objective optimization module is used to construct a comprehensive optimization objective function based on scaling risk value, corrosion risk value, chemical consumption cost and sewage discharge volume, and solve for the current optimal control parameters; 5) Dosing control module, which is electrically connected to the multi-channel dosing pump, is used to adjust the dosage and frequency of scale inhibitor, corrosion inhibitor and bactericide according to the optimization results; 6) Sewage control module, which is electrically connected to the sewage valve and the water supply valve, is used to dynamically adjust the system sewage discharge ratio and the opening of the sewage valve according to the optimization results, so as to control the system concentration ratio; 7) Feedback correction module, used to receive feedback signals such as the measured corrosion rate of the corrosion coupons, online iron ion concentration, and heat exchanger pressure drop changes, and to correct the model weight parameters and control thresholds; 8) Central control unit, used to realize data interaction between modules, issue control commands, display operating status and store historical data.

[0065] The online water quality monitoring unit specifically includes: a pH monitor; a conductivity meter; a chloride ion analyzer; a sulfate ion analyzer; a calcium ion or total hardness analyzer; an alkalinity analyzer; a dissolved oxygen monitor; a silica analyzer; a temperature sensor; a redox potential monitor; an online iron ion analyzer; a makeup water flow meter; a circulating water flow meter; and a sewage flow meter. The monitoring data is collected and then input into the central control unit, and then sent to the scaling risk calculation module and the corrosion risk calculation module respectively.

[0066] In this embodiment, the dosing control module corresponds to multiple independent dosing pumps and chemical storage tanks, and can independently adjust the dosage of scale inhibitor, corrosion inhibitor, oxidizing bactericide and non-oxidizing bactericide; the sewage control module controls the sewage valve and water supply valve in conjunction, and adjusts the system concentration ratio while maintaining the cooling tower liquid level.

[0067] In this embodiment, the central control unit is equipped with a human-machine interface, an over-limit alarm module, and a historical database. It supports manual parameter setting, operation trend display, and automatic report generation, and can be connected to a factory-level management and control system to achieve data exchange.

[0068] Furthermore, all parts of this application that are not described in detail are the same as or implemented using existing technology.

[0069] In summary: 1. This invention considers both scaling and corrosion risks, establishes a dynamic coupling relationship between these risks and the dosage of chemicals and the discharge ratio, and adopts a constrained dual-objective optimization algorithm. Under the premise of meeting the safety thresholds for scaling and corrosion, it comprehensively optimizes the dosage of chemicals and the discharge ratio, dynamically explores the potential for increasing the system's concentration ratio, and achieves precise matching between chemical dosage and discharge adjustment. This can improve the concentration ratio and reduce chemical consumption and discharge volume while ensuring equipment safety, thereby improving the overall safety, stability and economy of the circulating cooling water system. 2. This invention combines on-site feedback information to construct a dynamic feedback correction mechanism, which can continuously calibrate model parameters and control thresholds based on actual on-site operating data and maintenance results. The control accuracy is continuously iterated and optimized with operation, adapting to changes in operating conditions such as water quality fluctuations, seasonal changes, and equipment aging. The entire system has complete closed-loop control logic, enabling unmanned intelligent operation, reducing the intensity of manual maintenance, and adapting to different industries and circulating cooling water system scenarios with different materials.

[0070] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0071] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0072] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A closed-loop control method for the coordinated dosing and sludge discharge ratio of circulating cooling water, characterized in that, Includes the following steps: S1, Monitoring data acquisition and preprocessing: Collect water quality parameters and operating parameters of the circulating water side and makeup water side of the circulating cooling water system, and perform outlier removal, filtering and calibration preprocessing on the raw data to obtain standardized monitoring data; S2, Establishment of scaling risk model: Calculate scaling risk value based on the standardized monitoring data and construct a scaling risk assessment model for the circulating cooling water system; S3, Corrosion Risk Model Establishment: Based on the standardized monitoring data, calculate the corrosion risk value and construct a corrosion risk assessment model for the circulating cooling water system; S4, Construction and solution of the dual-objective optimization function: Establish a dual-objective comprehensive optimization function for scaling risk and corrosion risk with constraints, and obtain the optimal control parameters by solving the optimization algorithm; S5, Closed-loop control of dosing and discharge ratio: Dosing and discharge ratio are adjusted in conjunction with the optimal control parameters. Differentiated collaborative control strategies are implemented based on the relative levels of scaling risk and corrosion risk to achieve linkage matching of scaling inhibition, corrosion protection and discharge control. S6, Dynamic Feedback Correction and Adjustment: Collect actual system operation feedback data and dynamically correct the weight parameters and optimization function weights of the scaling risk model and corrosion risk model to form a fully closed-loop control loop.

2. The closed-loop control method for the coordinated dosing and sludge discharge ratio of circulating cooling water according to claim 1, characterized in that... In step S2, the scaling risk assessment model has the following expression: In the formula: This represents the scaling risk value. The Langrillly saturation index; This refers to the concentration of dissolved silicon in the circulating water. This refers to the calcium ion concentration in the circulating water. This is a concentration ratio correction factor; , , , These are the model weight coefficients for each parameter; The fouling risk assessment model can be further improved by introducing one or more of the following: temperature correction term, flow rate correction term, and local heat transfer surface heat flux correction term, in order to enhance the model's adaptability to the actual fouling trend of heat exchangers.

3. The closed-loop control method for the coordinated dosing and sludge discharge ratio of circulating cooling water according to claim 1, characterized in that... In step S3, the corrosion risk assessment model has the following expression: In the formula: This represents the corrosion risk value. This refers to the chloride ion concentration in the circulating water. This refers to the sulfate concentration in the circulating water. Dissolved oxygen concentration; This represents the deviation of the current pH value from the center value of the set corrosion control range. Temperature-related factors; , , , , These are the model weight coefficients for each parameter; Wherein, the model weight coefficients , , , , The selection is made in real time based on the main material of the circulating water pipeline on site, in order to adapt to the metal corrosion mechanism of different pipeline materials.

4. The closed-loop control method for the coordinated dosing and sludge discharge ratio of circulating cooling water according to claim 3, characterized in that, when At mg / L, a high-chlorine enhancement weighting correction factor is introduced into the chloride ion term. This modifies the corrosion risk model expression to: in .

5. The closed-loop control method for the coordinated dosing and sludge discharge ratio of circulating cooling water according to claim 1, characterized in that... In step S4, the dual-objective comprehensive optimization function for scaling risk and corrosion risk is: In the formula, To comprehensively optimize the objective function; This represents the scaling risk value. This represents the corrosion risk value. The cost of drug consumption per unit time or the total amount of drug consumed; This refers to the amount of sewage discharged per unit time. , , , These are the weighting coefficients for each item; The optimization constraints include: In the formula, This is the corrosion safety threshold; This represents the allowable threshold for scaling.

6. The closed-loop control method for the coordinated dosing and sludge discharge ratio of circulating cooling water according to claim 1, characterized in that, The optimization algorithm can specifically employ any one of linear programming, nonlinear programming, genetic algorithm, particle swarm optimization, or model predictive control algorithm to perform the optimization solution. The optimal control parameters include: scale inhibitor dosage, corrosion inhibitor dosage, bactericide dosage frequency and dosage cycle, sewage discharge ratio and sewage discharge valve adjustment parameters, and target concentration ratio.

7. The closed-loop control method for the coordinated dosing and sludge discharge ratio of circulating cooling water according to claim 1, characterized in that... In step S5, the closed-loop control of the dosage and discharge ratio includes: 1) When the scaling risk Rs increases while the corrosion risk Rc is low, prioritize increasing the dosage of scale inhibitor, maintain or slightly adjust the blowdown ratio, so that the system can suppress the scaling trend without significantly increasing the corrosion risk. 2) When the corrosion risk Rc increases while the scaling risk Rs is controllable, prioritize increasing the discharge volume, reducing the concentration ratio, and simultaneously increasing the dosage of corrosion inhibitor to rapidly reduce the enrichment of corrosive ions. 3) When both scaling risk Rs and corrosion risk Rc increase simultaneously, prioritize ensuring that the corrosion risk meets the safety threshold requirements. On this basis, adjust the scale inhibitor, corrosion inhibitor, and blowdown ratio simultaneously. If necessary, reduce the system recovery rate or reduce the operating concentration ratio. 4) When the risk of microbial slime increases, adjust the frequency of bactericide shock dosing based on changes in redox potential, turbidity, pressure difference, and colony trends to avoid slime deposition inducing localized corrosion and under-deposit corrosion.

8. The closed-loop control method for the coordinated dosing and sludge discharge ratio of circulating cooling water according to claim 1, characterized in that... In step S6, the actual operation feedback data of the system includes: the measured rate of corrosion of the coupons, the online iron ion concentration, the change of pressure drop at the inlet and outlet of the heat exchanger, the change of heat transfer temperature difference of the heat exchanger, the pressure drop or blockage trend of the cooling tower packing, and the results of sediment thickness and composition analysis obtained during system shutdown and maintenance. The dynamic feedback correction adjustment includes: 1) When the measured corrosion rate of the corrosion coupon is higher than the corresponding value predicted by the model, increase the weight of the corrosion risk term. Or increase the weighting coefficients for chloride ions and dissolved oxygen; 2) When the pressure drop or heat transfer degradation of the heat exchanger exceeds the corresponding value predicted by the model, increase the weight of the scaling risk term. Or increase the coefficients of the correction terms for silica, calcium ions, and concentration ratio; 3) When drug consumption is high but risk indicators are stable, the weight of drug consumption items should be appropriately increased. This prompts the optimization algorithm to be modified towards lower drug consumption. 4) When the discharge volume is consistently high and there is sufficient capacity for corrosion and scaling, the weight of the discharge item should be appropriately increased. This will drive the system to operate at a higher concentration ratio.

9. A circulating cooling water control system employing the closed-loop control method for coordinated dosing and sludge discharge ratio of circulating cooling water as described in any one of claims 1 to 8, characterized in that, include: 1) Online monitoring instrument unit, deployed in the circulating water main pipe, water supply main pipe and sewage pipe, is used to collect water quality parameters and operating parameters of the circulating cooling water system in real time, and to perform signal conversion and monitoring data preprocessing; 2) Scaling risk calculation module, used to receive pre-processed monitoring data and call the scaling risk model to calculate the real-time scaling risk value; 3) Corrosion risk calculation module, used to receive preprocessed monitoring data and call the corrosion risk model to calculate real-time corrosion risk value; 4) A dual-objective optimization module is used to construct a comprehensive optimization objective function based on scaling risk value, corrosion risk value, chemical consumption cost and sewage discharge volume, and solve for the current optimal control parameters; 5) Dosing control module, used to adjust the dosage and frequency of scale inhibitors, corrosion inhibitors and bactericides based on optimization results; 6) Sewage control module, used to dynamically adjust the system sewage discharge ratio and sewage valve opening based on optimization results, so as to control the system concentration ratio; 7) Feedback correction module, used to receive feedback signals such as the measured corrosion rate of the corrosion coupons, online iron ion concentration, and heat exchanger pressure drop changes, and to correct the model weight parameters and control thresholds; 8) Central control unit, used to realize data interaction between modules, issue control commands, display operating status and store historical data.

10. The circulating cooling water control system according to claim 9, characterized in that, The dosing control module corresponds to multiple independent dosing pumps and chemical storage tanks, and can independently adjust the dosage of scale inhibitors, corrosion inhibitors, oxidizing bactericides and non-oxidizing bactericides; the sewage control module controls the sewage valve and water supply valve in conjunction, and adjusts the system concentration ratio while maintaining the cooling tower liquid level.

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