Corrosion and scale inhibition and sterilization intelligent control system for chemical circulating water system

Abstract

The invention discloses a corrosion and scale inhibition and sterilization intelligent control system for a chemical circulating water system, and belongs to the technical field of chemical circulating water treatment. The system comprises an online water quality monitoring sensor, a circulating water flow sensor, a control unit, a variable-frequency dosing pump and a medicament storage unit which are arranged on a circulating water main pipeline, the online water quality monitoring sensor detects the pH value, hardness, conductivity and residual chlorine parameters of circulating water in real time, the control unit receives data of the sensor and analyzes the water quality trend through a built-in algorithm, the variable-frequency dosing pump is controlled to accurately add chemicals from the dosing tank, and meanwhile the dosing frequency is automatically adjusted according to the flow of the circulating water. And the dosing tank is provided with a liquid level sensor to monitor the residual amount of the medicament. The system realizes automatic monitoring of circulating water quality and accurate dosing, effectively maintains water quality stability, reduces medicament consumption, and guarantees safe and stable operation of the system.

Description

Technical Field

[0001] This invention relates to the field of maintenance and management technology for circulating water systems, and in particular to an intelligent control system for corrosion inhibition, scale inhibition, and sterilization in chemical circulating water systems. Background Technology

[0002] In chemical production processes, circulating water systems play a crucial role, removing heat generated by process equipment to ensure continuous and stable production. However, long-term use of circulating water inevitably leads to several problems. Firstly, dissolved minerals and salts in the water concentrate as it evaporates, increasing water hardness and causing scale buildup on pipes, heat exchangers, and other equipment. Scale not only reduces heat exchange efficiency and increases energy consumption but can also clog pipes, hindering normal water flow and potentially causing production accidents. Secondly, circulating water typically contains corrosive substances such as dissolved oxygen and acidic gases. These substances react chemically with metal equipment components, causing corrosion, shortening equipment lifespan, and increasing maintenance and replacement costs. Furthermore, the suitable temperature and abundant nutrients in circulating water create a breeding ground for microorganisms. The biofilm formed by the proliferation of microorganisms further reduces heat transfer efficiency and may trigger microbial corrosion, exacerbating equipment damage. Simultaneously, the resulting sludge and other impurities affect water quality, increasing the difficulty of subsequent treatment.

[0003] Traditional methods involve periodically sampling and testing the circulating water quality, then relying on experience to determine the dosage of corrosion inhibitors, scale inhibitors, and bactericides. This approach suffers from significant lag and subjectivity, failing to adapt to dynamic changes in water quality in real time. It easily leads to overdosing or underdosing of chemicals, wasting resources and failing to effectively ensure the healthy and stable operation of the circulating water system. Therefore, there is an urgent need for an intelligent and precise monitoring device to address these issues. Furthermore, some automated treatment devices have emerged, such as dosing systems with fixed program control or monitoring and control equipment based on a single parameter (e.g., conductivity). However, these methods or devices still suffer from response lag, insufficient control precision, and weak multi-parameter coordinated control capabilities. They are ill-suited to the complex operating conditions of dynamically changing water quality in chemical circulating water systems, easily leading to overdosing or underdosing of chemicals and failing to fundamentally guarantee the long-term stable and efficient operation of the system.

[0004] Therefore, there is an urgent need for an intelligent and precise intelligent control system for chemical circulating water systems to solve these problems. Summary of the Invention

[0005] The purpose of this invention is to provide an intelligent control system that can monitor the water quality of chemical circulating water in real time and accurately control the dosage of chemicals to solve the problems of corrosion, scaling and microbial growth, aiming to improve the operational stability, energy saving and consumption reduction and the level of intelligence of chemical circulating water systems.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A smart control system for corrosion inhibition, scale inhibition, and sterilization in a chemical circulating water system includes: an online water quality monitoring unit, a circulating water flow sensor, a control unit, a variable frequency dosing pump, and a reagent storage unit. The online water quality monitoring unit is located at at least one of the inlet / outlet of a heat exchanger and the suction port of the circulating water pump. The circulating water flow sensor is installed on the main circulating water pipeline. Both the online water quality monitoring unit and the circulating water flow sensor are communicatively connected to the control unit. The control unit is communicatively connected to the variable frequency dosing pump. The variable frequency dosing pump is connected to the reagent storage unit. The reagent storage unit is equipped with a level sensor, which is communicatively connected to the control unit. The control unit includes a data receiving module, a data analysis module, a reagent dosage calculation module, and a control command output module.

[0008] Preferably, the online water quality monitoring unit includes a pH sensor, a hardness sensor, a conductivity sensor, and a residual chlorine sensor.

[0009] Preferably, the pH sensor is a glass electrode sensor; the hardness sensor is an online analyzer based on the principle of complexometric titration; the conductivity sensor is a four-electrode sensor; and the residual chlorine sensor is an online detector based on the principle of polarography or DPD spectrophotometry.

[0010] Preferably, the control unit is any one of a programmable logic controller, an industrial computer, or a distributed control system.

[0011] Preferably, the flow rate adjustment ratio of the variable frequency dosing pump is 1:10 to 1:20.

[0012] Preferably, the reagent storage unit includes a corrosion inhibitor reagent storage unit, a scale inhibitor reagent storage unit, and a bactericide reagent storage unit.

[0013] Preferably, the intelligent control system for corrosion inhibition, scale inhibition, and sterilization of the chemical circulating water system further includes an alarm module and a communication module. The alarm module is electrically connected to the control unit, and the communication module is data connected to the control unit.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] (1) Stable control of circulating water quality has been achieved. Through real-time monitoring and automatic adjustment, water quality indicators are effectively maintained within the set range, thus improving the stability of system operation.

[0016] (2) Reduced the consumption and operating costs of chemicals. By accurately adding chemicals, waste of chemicals was avoided, and equipment maintenance costs caused by water quality problems were reduced.

[0017] (3) Improved the reliability of system operation. Through liquid level monitoring and abnormal alarm functions, system abnormalities can be detected and handled in a timely manner, ensuring the continuous and stable operation of the device.

[0018] (4) It reduced the frequency of manual operation, realized automated control from water quality monitoring to chemical dosing, and reduced the labor intensity of operators.

[0019] (5) It extends the service life of equipment and reduces the risk of damage to heat exchangers, pipelines and other equipment by effectively controlling scaling and corrosion problems.

[0020] (6) It adopts a modular design, which is convenient for configuration and expansion according to actual needs and has good applicability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the intelligent control system for corrosion inhibition, scale inhibition, and sterilization in a chemical circulating water system proposed in this invention.

[0022] Explanation of reference numerals in the attached diagram: 1. Circulating water inlet; 2. Heat exchanger; 3. Circulating water outlet; 4. pH sensor; 5. Water hardness sensor; 6. Conductivity sensor; 7. Residual chlorine sensor, located at the heat exchanger outlet to monitor the sterilization effect; 8. Signal transmission line; 9. PLC controller; 10. Control command line; 11. Variable frequency dosing pump; 12. Corrosion inhibitor dosing tank; 13. Scale inhibitor dosing tank; 14. Bactericide dosing tank; 15. Dosing point; 16. Circulating water flow sensor; 17. Circulating water pump. Detailed Implementation

[0023] 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.

[0024] Reference Figure 1 The intelligent control system for corrosion inhibition, scale inhibition and sterilization of chemical circulating water system provided by the present invention mainly consists of four parts: water quality monitoring unit, control unit, dosing execution unit and reagent storage unit.

[0025] The water quality monitoring unit includes multiple online sensors installed at key locations on the main circulating water pipeline. Specifically, a pH sensor 4 is installed near the heat exchanger inlet. This sensor is a glass electrode type with a measurement accuracy of ±0.01pH to ±0.05pH, used for real-time monitoring of the circulating water's acidity and alkalinity. A hardness sensor 5 is installed on the main circulating water pipeline. This sensor uses an online analyzer based on the principle of complexometric titration, with a measurement range of 0-500ppm, used to detect the concentration of calcium and magnesium ions in the water. A conductivity sensor 6 is installed near the suction port of the circulating water pump 17. This sensor is a four-electrode type with a measurement accuracy of ±1μS / cm to ±5μS / cm, used to reflect the total ion concentration in the water and the system's concentration factor. A residual chlorine sensor 7 is installed on the heat exchanger outlet pipeline to monitor the sterilization effect. All sensors are connected to the control unit via signal transmission line 8. In addition, a circulating water flow sensor 16 is integrated into the circulating water pipeline to monitor the system's real-time flow rate.

[0026] The control unit uses a programmable logic controller (PLC) 9 as the core processing hub of the entire device. The PLC 9 receives signals from all water quality and flow sensors through its input modules, stores preset water quality control parameters internally, and runs a dedicated control algorithm program. The data analysis module is configured to analyze and process water quality data from 30 minutes to 2 hours.

[0027] The dosing unit consists of a variable frequency dosing pump 11, which is connected to a PLC 9 via a control command line 10 and receives control commands from the PLC. The variable frequency dosing pump 11 can steplessly adjust the motor speed according to the commands, thereby precisely controlling the output flow rate of the chemical. The pump body is made of polytetrafluoroethylene, fluororubber, or stainless steel, and the flow control accuracy is ±5% to ±10%.

[0028] The chemical storage unit comprises three independent dosing tanks: a corrosion inhibitor dosing tank 12, a scale inhibitor dosing tank 13, and a bactericide dosing tank 14. Each tank is constructed of corrosion-resistant material and has excellent sealing properties. The tanks are equipped with level sensors, which communicate with PLC 9 to monitor the remaining chemical levels in real time and issue an alarm when the level is too low. The dosing tanks are connected to the inlet of the variable frequency dosing pump 11 via piping, and the pump outlet is connected to the circulating water pipeline via dosing point 15.

[0029] After the system is started, its workflow is as follows: Circulating water enters from the inlet 1, flows through the heat exchanger 2 to complete heat exchange, and then flows out from the outlet 3, forming a circulation loop; during the water circulation process, water quality monitoring sensors distributed at various key points continuously monitor the circulating water in real time and transmit the signal characterizing the water quality status to the PLC 9 in real time through the signal transmission line 8. At the same time, the circulating water flow sensor 16 also feeds back the real-time flow signal of the system to the PLC 9.

[0030] Upon receiving the aforementioned multiple signals, PLC 9 activates its internally integrated intelligent control algorithm. The algorithm's execution process is as follows: First, the acquired real-time data is filtered and standardized. Next, a trend prediction method is used to analyze recent water quality data sequences and predict the changing trends of key parameters. Then, the real-time data and predicted trends are compared with preset water quality control target values, and calculations are performed based on the built-in mathematical model to accurately determine the instantaneous dosage of corrosion inhibitors, scale inhibitors, and bactericides required to maintain stable water quality.

[0031] PLC 9 sends the calculated chemical dosing command to variable frequency dosing pump 11 via control command line 10. Variable frequency dosing pump 11 precisely adjusts its operating frequency according to this command, thereby changing the motor speed and achieving precise control of the chemical output flow rate. The added chemical is injected into the circulating water pipeline through dosing point 15, fully mixing with the circulating water to inhibit corrosion, scale, and bacteria. The entire control process constitutes a closed-loop feedback system, capable of automatically adjusting the dosing strategy based on dynamic changes in water quality.

[0032] In addition, the device has auxiliary functions. The liquid level sensor in the dosing tank continuously monitors the chemical supply. When the liquid level of any chemical falls below a set threshold, it triggers the alarm program of PLC 9. PLC 9 also has an emergency response program. When abnormal situations such as a sharp deterioration in water quality parameters are detected, it can automatically increase the dosing rate of the corresponding chemical and send alarm information to the remote monitoring center via the communication module to ensure system safety.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or substitute or modify some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A smart control system for corrosion inhibition, scale inhibition, and sterilization in a chemical circulating water system, characterized in that, include: Online water quality monitoring unit, circulating water flow sensor, control unit, variable frequency dosing pump and reagent storage unit; The online water quality monitoring unit is installed at at least one of the heat exchanger inlet / outlet and the circulating water pump suction port. The circulating water flow sensor is installed on the main circulating water pipeline. Both the online water quality monitoring unit and the circulating water flow sensor are communicatively connected to the control unit. The control unit is communicatively connected to the variable frequency dosing pump. The variable frequency dosing pump is connected to the chemical storage unit. The chemical storage unit is equipped with a liquid level sensor, which is communicatively connected to the control unit. The control unit includes a data receiving module, a data analysis module, a chemical dosage calculation module, and a control command output module.

2. The intelligent control system for corrosion inhibition, scale inhibition, and sterilization of chemical circulating water systems according to claim 1, characterized in that, The online water quality monitoring unit includes a pH sensor, a hardness sensor, a conductivity sensor, and a residual chlorine sensor.

3. The intelligent control system for corrosion inhibition, scale inhibition, and sterilization of chemical circulating water systems according to claim 2, characterized in that, The pH sensor is a glass electrode sensor; the hardness sensor is an online analyzer based on the principle of complexometric titration; the conductivity sensor is a four-electrode sensor; and the residual chlorine sensor is an online detector based on the principle of polarography or DPD spectrophotometry.

4. The intelligent control system for corrosion inhibition, scale inhibition, and sterilization of chemical circulating water systems according to claim 1, characterized in that, The control unit can be any one of a programmable logic controller, an industrial computer, or a distributed control system.

5. The intelligent control system for corrosion inhibition, scale inhibition, and sterilization of chemical circulating water systems according to claim 1, characterized in that, The flow rate adjustment ratio of the variable frequency dosing pump is 1:10 to 1:

20.

6. The intelligent control system for corrosion inhibition, scale inhibition, and sterilization of chemical circulating water systems according to claim 1, characterized in that, The chemical storage unit includes a corrosion inhibitor storage unit, a scale inhibitor storage unit, and a bactericide storage unit.

7. The intelligent control system for corrosion inhibition, scale inhibition, and sterilization of chemical circulating water systems according to claim 1, characterized in that, The system also includes an alarm module and a communication module. The alarm module is electrically connected to the control unit, and the communication module is data connected to the control unit.

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