A method for controlling corrosion and scale inhibition of circulating water

Abstract

This invention discloses a method for controlling the chemical dosing of circulating water to prevent corrosion and scaling, comprising: S1: continuously collecting circulating water samples in real time through an online water quality monitoring probe to obtain measured pH value, water temperature (t), total dissolved solids (TDS), calcium hardness, and total alkalinity, and uploading the data to the control host in real time; S2: calculating the Langerile saturation index (LSI) based on the data uploaded to the control host; S3: classifying the circulating water quality level and judging the circulating water quality based on the LSI; S4: generating a corresponding dosing strategy based on the circulating water quality, and performing dosing according to the dosing strategy; S5: repeating steps S1 to S4 after dosing, which has the advantages of high automation and precise control.

Description

Technical Field

[0001] This invention relates to the field of circulating cooling water systems for bar production, and in particular to a method for controlling corrosion and scaling in circulating water by adding chemicals. Background Technology

[0002] Corrosion and scaling are common problems in the operation of circulating cooling water systems in production lines. Existing chemical dosing control methods have significant shortcomings: they rely heavily on manual, experience-based dosing, making it impossible to adjust according to real-time water quality; they only add scale inhibitors or corrosion inhibitors, failing to automatically switch between agents based on scaling and corrosion trends; fixed dosages easily lead to overdosing and waste or underdosing and ineffectiveness; existing closed-loop control logic cannot adapt to conditions with high concentration ratios and large fluctuations in water quality, making it difficult to achieve efficient corrosion and scaling control. Current circulating water chemical dosing methods mostly employ continuous dosing, resulting in problems such as overdosing, energy waste, and excessive agent residues in the water; continuous dosing cannot match the slow changes in circulating water quality, easily causing large fluctuations in water quality and unstable scaling and corrosion control; furthermore, they lack synergistic control logic for intermittent dosing and water quality stabilization, making it impossible to adaptively adjust the dosing cycle and duration based on real-time water quality conditions, thus failing to achieve the dual goals of water conservation, chemical conservation, and water quality stability.

[0003] This application provides a method for controlling corrosion and scaling in circulating water by adding chemicals to solve the above-mentioned problems. Summary of the Invention

[0004] The main objective of this invention is to address the problems in the existing technology where chemical dosing control is mostly done manually, which cannot be adjusted according to the real-time water quality status, cannot switch chemical types according to different water quality trends, and the dosage is relatively fixed, which easily leads to excessive dosage and waste, making it difficult to achieve the dual goals of water conservation, chemical conservation and water quality stability.

[0005] This invention provides a method for controlling corrosion and scaling prevention in circulating water by adding chemicals, the method comprising:

[0006] S1: Continuously collect circulating water samples in real time through online water quality monitoring probes to obtain measured pH value, water temperature t, total dissolved solids TDS, calcium hardness and total alkalinity of the water body and upload the data to the control host in real time; S2: Calculate the Langrillly Saturation Index (LSI) using data uploaded to the control host; S3: Classify the quality level of circulating water and judge the quality of circulating water based on the Langrillly Saturation Index (LSI); S4: The dosing execution agency generates a corresponding dosing strategy based on the circulating water quality, and the dosing execution agency performs dosing according to the dosing strategy; S5: After completing the drug administration, repeat steps S1 to S4.

[0007] Furthermore, the calculation of the Langerier Saturation Index (LSI) includes: Calculate the ionic strength correction factor A: A = (lgTDS) 1)÷10; Calculate the temperature correction factor B: B = 0.011×t+2.05, where t is the water temperature; Calculate the calcium hardness correction factor C: C = lg (calcium hardness); Calculate the total alkalinity correction factor D: D = lg (total alkalinity); Calculate the saturated pH value of calcium carbonate: pHs = 9.3 + A + B C D; Calculate the Langerier Saturation Index (LSI): LSI = Measured pH value pHs.

[0008] Furthermore, the classification of circulating water quality grades includes: The quality of circulating water is divided into four levels: circulating water with a strong tendency to corrode; circulating water with a weak tendency to corrode; circulating water with no obvious scaling and corrosion; and circulating water with a tendency to scale.

[0009] Furthermore, the determination of circulating water quality based on the Langerile Saturation Index (LSI) includes: When the Langerile Saturation Index (LSI) is less than -0.5, the circulating water quality is characterized by a strong tendency to corrode. When -0.5 ≤ Langerile saturation index LSI < 0, the circulating water quality has a weak tendency to corrode. When 0 ≤ Langerile saturation index (LSI) ≤ 0.5, the circulating water quality is free from significant scaling and corrosion. When the Langerile Saturation Index (LSI) is greater than 0.5, the circulating water quality is prone to scaling.

[0010] Furthermore, the step between step S3 and step S4 also includes: The control unit converts the corrosion and scaling determination results into 4-20mA analog signals or digital communication signals, which are transmitted to the automatic dosing control cabinet in real time. The signals correspond one-to-one with the water quality level.

[0011] Furthermore, the dosing agency formulates corresponding dosing strategies based on the circulating water quality, including: Automatically switch dosing pipelines and chemical types according to preset logic: When a strong / weak corrosion tendency is determined: the scale inhibitor pipeline is automatically shut off, the corrosion inhibitor pipeline is opened, and the addition of corrosion inhibitor is locked. When scaling tendency is detected: automatically shut off the anti-corrosion agent pipeline, open the scale inhibitor pipeline, and lock the scale inhibitor dosage; When the water quality is determined to be stable: simultaneously shut off the scale inhibitor and corrosion inhibitor pipelines, stop adding chemicals or add a small amount of water quality stabilizer.

[0012] Furthermore, it also includes: The corrosion tendency control strategy is as follows: the smaller the Langerile Saturation Index (LSI) value, the greater the amount of corrosion inhibitor added, and the amount added is directly proportional to the Langerile Saturation Index (LSI) value. The strategy for controlling scaling tendency is as follows: the larger the Langerile Saturation Index (LSI) value, the greater the dosage of scale inhibitor, and the dosage is directly proportional to the LSI value. The strategy for controlling the stable range is to reduce the dosage to 0 or maintain the baseline stable dose.

[0013] Furthermore, it also includes automatically switching to continuous dosing mode when the Langerilla Saturation Index (LSI) exceeds the safety threshold to quickly restore water quality, and then returning to intermittent control after recovery.

[0014] This invention achieves precise quantification of corrosion and scaling trends in circulating water through online monitoring and real-time LSI calculation. This quantification drives automatic switching of reagent types and adaptive adjustment of dosage, forming a fully closed-loop control system. Compared to traditional timed or manual dosing, its advantages include: rapid response to dynamic water quality changes, avoiding over- or under-dosing, effectively suppressing corrosion and scaling risks while significantly reducing reagent consumption and operating costs; intermittent dosing mode combined with continuous protection against anomalies, balancing daily energy saving with rapid recovery from sudden situations; and maintaining water quality stably within the optimal LSI range, extending the service life of equipment and pipelines, and improving the automation and intelligence level of the circulating water system. Attached Figure Description

[0015] Figure 1 The flowchart shows the circulating water anti-corrosion and scaling chemical dosing control method provided by the present invention. Detailed Implementation

[0016] The technical solution of the present invention will now be clearly and completely described in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0017] Example This embodiment provides a method for controlling the addition of chemicals for corrosion and scaling prevention in circulating water. The method includes: S1: Continuously collect circulating water samples in real time through online water quality monitoring probes to obtain measured pH value, water temperature t, total dissolved solids TDS, calcium hardness and total alkalinity of the water body and upload the data to the control host in real time; S2: Calculate the Langerilla Saturation Index (LSI) using data uploaded to the control host; the LSI calculation includes: Calculate the ionic strength correction factor A: A = (lgTDS) 1)÷10; Calculate the temperature correction factor B: B = 0.011×t+2.05, where t is the water temperature; Calculate the calcium hardness correction factor C: C = lg (calcium hardness); Calculate the total alkalinity correction factor D: D = lg (total alkalinity); Calculate the saturated pH value of calcium carbonate: pHs = 9.3 + A + B C D; Calculate the Langerier Saturation Index (LSI): LSI = Measured pH value pHs.

[0018] S3: Classify circulating water quality according to the Langerile Indices (LSI); the classification of circulating water quality includes: The quality of circulating water is divided into four levels: circulating water with a strong tendency to corrode; circulating water with a weak tendency to corrode; circulating water with no obvious scaling and corrosion; and circulating water with a tendency to scale.

[0019] The quality of circulating water is determined based on the Langerier Saturation Index (LSI), including: When the Langerile Saturation Index (LSI) is less than -0.5, the circulating water quality is characterized by a strong tendency to corrode. When -0.5 ≤ Langerile saturation index LSI < 0, the circulating water quality has a weak tendency to corrode. When 0 ≤ Langerile saturation index (LSI) ≤ 0.5, the circulating water quality is free from significant scaling and corrosion. When the Langerile Saturation Index (LSI) is greater than 0.5, the circulating water quality is prone to scaling.

[0020] The control unit converts the corrosion and scaling determination results into 4-20mA analog signals or digital communication signals, which are transmitted to the automatic dosing control cabinet in real time. The signals correspond one-to-one with the water quality level.

[0021] S4: The dosing execution agency generates a corresponding dosing strategy based on the circulating water quality, and the dosing execution agency performs dosing according to the dosing strategy; The dosing agency generates corresponding dosing strategies based on the circulating water quality, including: Automatically switch dosing pipelines and chemical types according to preset logic: When a strong / weak corrosion tendency is determined: the scale inhibitor pipeline is automatically shut off, the corrosion inhibitor pipeline is opened, and the addition of corrosion inhibitor is locked. When scaling tendency is detected: automatically shut off the anti-corrosion agent pipeline, open the scale inhibitor pipeline, and lock the scale inhibitor dosage; When the water quality is determined to be stable: simultaneously shut off the scale inhibitor and corrosion inhibitor pipelines, stop adding chemicals or add a small amount of water quality stabilizer.

[0022] It also includes: the corrosion tendency control strategy is: the smaller the Langerier Saturation Index (LSI) value, the greater the amount of corrosion inhibitor added, and the amount added is directly proportional to the Langerier Saturation Index (LSI) value; The strategy for controlling scaling tendency is as follows: the larger the Langerile Saturation Index (LSI) value, the greater the dosage of scale inhibitor, and the dosage is directly proportional to the LSI value. The strategy for controlling the stable range is to reduce the dosage to 0 or maintain the baseline stable dose.

[0023] S5: After completing the drug administration, repeat steps S1 to S4.

[0024] It also includes automatically switching to continuous dosing mode when the Langerilla Saturation Index (LSI) exceeds the safety threshold to quickly restore water quality, and then returning to intermittent control after recovery.

[0025] In a specific embodiment, the circulating water test data for a certain bar stock are as follows: pH=7.8, water temperature 32℃, TDS=1250mg / L, calcium hardness 220mg / L, total alkalinity 180mg / L; the control host calculates A≈0.2096, B=1.698, C≈2.3424, D≈2.2553, pHs≈6.61, LSI=1.19 (scaling tendency). The system outputs a scaling control signal, and the dosing control cabinet automatically switches to the scale inhibitor pipeline. The frequency of the dosing pump is increased according to the deviation of LSI=1.19. The system sets the scale inhibitor dosing time to 120s and the dosing interval to 300s. After intermittent dosing, the LSI drops to 0.4 (stable), and the system automatically stops dosing, with the interval extended to 600s. If the detected LSI=-0.7 (corrosion tendency), the system switches to the corrosion inhibitor, with a dosing time of 100s and an interval of 240s, until the water quality returns to the stable range.

[0026] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for controlling corrosion and scaling in circulating water by adding chemicals, characterized in that, include: S1: Continuously collect circulating water samples in real time through online water quality monitoring probes to obtain measured pH value, water temperature t, total dissolved solids TDS, calcium hardness and total alkalinity of the water body and upload the data to the control host in real time; S2: Calculate the Langrillly Saturation Index (LSI) using data uploaded to the control host; S3: Classify the quality level of circulating water and judge the quality of circulating water based on the Langrillly Saturation Index (LSI); S4: The dosing execution agency generates a corresponding dosing strategy based on the circulating water quality, and the dosing execution agency performs dosing according to the dosing strategy; S5: After completing the drug administration, repeat steps S1 to S4.

2. The method for controlling corrosion and scaling in circulating water according to claim 1, characterized in that, The calculation of the Langrillly Saturation Index (LSI) includes: Calculate the ionic strength correction factor A: A = (lgTDS) 1)÷10; Calculate the temperature correction factor B: B = 0.011×t+2.05, where t is the water temperature; Calculate the calcium hardness correction factor C: C = lg (calcium hardness); Calculate the total alkalinity correction factor D: D = lg (total alkalinity); Calculate the saturated pH value of calcium carbonate: pHs = 9.3 + A + B C D; Calculate the Langerier Saturation Index (LSI): LSI = Measured pH value pHs.

3. The method for controlling corrosion and scaling in circulating water according to claim 2, characterized in that, The classification of circulating water quality grades includes: The quality of circulating water is divided into four levels: circulating water with a strong tendency to corrode; circulating water with a weak tendency to corrode; circulating water with no obvious scaling and corrosion; and circulating water with a tendency to scale.

4. The method for controlling corrosion and scaling in circulating water according to claim 3, characterized in that, The determination of circulating water quality based on the Langerier Saturation Index (LSI) includes: When the Langerile Saturation Index (LSI) is less than -0.5, the circulating water quality is characterized by a strong tendency to corrode. When -0.5 ≤ Langerile saturation index LSI < 0, the circulating water quality has a weak tendency to corrode. When 0 ≤ Langerile saturation index (LSI) ≤ 0.5, the circulating water quality is free from significant scaling and corrosion. When the Langerile Saturation Index (LSI) is greater than 0.5, the circulating water quality is prone to scaling.

5. The method for controlling corrosion and scaling in circulating water according to claim 4, characterized in that, Between step S3 and step S4, the following is also included: The control unit converts the corrosion and scaling determination results into 4-20mA analog signals or digital communication signals, which are transmitted to the automatic dosing control cabinet in real time. The signals correspond one-to-one with the water quality level.

6. The method for controlling corrosion and scaling in circulating water according to claim 5, characterized in that, The dosing agency generates corresponding dosing strategies based on the circulating water quality, including: Automatically switch dosing pipelines and chemical types according to preset logic: When a strong / weak corrosion tendency is determined: the scale inhibitor pipeline is automatically shut off, the corrosion inhibitor pipeline is opened, and the addition of corrosion inhibitor is locked. When scaling tendency is detected: automatically shut off the anti-corrosion agent pipeline, open the scale inhibitor pipeline, and lock the scale inhibitor dosage; When the water quality is determined to be stable: simultaneously shut off the scale inhibitor and corrosion inhibitor pipelines, stop adding chemicals or add a small amount of water quality stabilizer.

7. The method for controlling corrosion and scaling in circulating water according to claim 6, characterized in that, Also includes: The corrosion tendency control strategy is as follows: the smaller the Langerile Saturation Index (LSI) value, the greater the amount of corrosion inhibitor added, and the amount added is directly proportional to the Langerile Saturation Index (LSI) value. The strategy for controlling scaling tendency is as follows: the larger the Langerile Saturation Index (LSI) value, the greater the dosage of scale inhibitor, and the dosage is directly proportional to the LSI value. The strategy for controlling the stable range is to reduce the dosage to 0 or maintain the baseline stable dose.

8. The method for controlling corrosion and scaling in circulating water according to claim 7, characterized in that, It also includes automatically switching to continuous dosing mode when the Langerilla Saturation Index (LSI) exceeds the safety threshold to quickly restore water quality, and then returning to intermittent control after recovery.

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