Method and system for reducing use amount of rinsing water in continuous pickling process section of strip steel

Abstract

The invention relates to the technical field of strip steel pickling, and discloses a method for reducing the use amount of rinsing water in a continuous strip steel pickling process section, a multi-stage rinsing process is adopted, a conductivity detector is arranged in a last-stage rinsing tank to detect the conductivity in real time, and the running state of a unit is interlocked with a rinsing water pump. Spraying and water replenishing are automatically started based on the running state of the unit, the minimum water replenishing amount is set based on the running speed of the unit, water replenishing is conducted with the minimum water replenishing amount in the running period, and when the conductivity detection value exceeds the conductivity threshold value, the maximum water replenishing amount is adjusted for rapid water replenishing. The invention further provides a system for implementing the method. By means of the method, on the premise that the strip steel rinsing quality is guaranteed, the rinsing water consumption can be greatly reduced, the average rinsing water consumption before improvement is 10.0 m < 3 > / h, the average rinsing water consumption after improvement is 5.0 m < 3 > / h, the production cost of a pickling unit is reduced, and therefore the benefits of enterprises are improved.

Description

Technical Field

[0001] The invention relates to the technical field of strip steel pickling, in particular to a method for reducing the amount of rinsing water used in a continuous pickling process section of strip steel. Background Art

[0002] Continuous pickling involves pickling, rinsing, squeezing, and drying. Rinsing is crucial for continuous pickling of metal strip. With the development of industrialization, continuous pickling has become the mainstream method for pickling metal strip due to its stable product quality and high production efficiency.

[0003] After pickling, residual acid remains on the surface of metal sheets and strips. If not promptly treated, this residual acid can cause corrosion on the metal surface, leading to color differences, rust, and even corrosion, seriously affecting the surface quality of the product. The current rinsing process primarily uses water flushing to dilute and remove residual acid, thereby preventing metal corrosion. This method is economical and simple to operate.

[0004] However, existing rinsing processes have significant drawbacks. For example, continuous pickling lines for steel strip typically employ a four-stage rinsing process, with a conductivity detection device installed in the final four-stage rinsing tank to control the amount of rinse water added. However, under the existing control model, conductivity directly controls the water addition, resulting in delayed water quality regulation and often leading to problems such as frequent and large rinse water additions.

[0005] Therefore, there is a need in the prior art for an improved method for reducing the amount of rinsing water used in the continuous pickling process section of steel strips. Summary of the Invention

[0006] In view of this, the purpose of the embodiments of the present invention is to propose a method and system for reducing the amount of rinsing water used in the continuous pickling process of strip steel, regulating the amount of water replenishment based on the operating speed of the unit, and avoiding the problems of frequent and large amounts of rinsing water replenishment.

[0007] Based on the above-mentioned purpose, an embodiment of the present invention provides a method for reducing the amount of rinsing water used in the continuous pickling process section of strip steel, wherein a multi-stage rinsing process is adopted, and a conductivity detector is set in the last-stage rinsing tank to detect the conductivity in real time. The unit operation status is interlocked with the rinsing water pump, and spraying and water replenishment are automatically started based on the unit operation status. The minimum water replenishment amount is set based on the unit operation speed. Water is replenished at the minimum water replenishment amount during operation. In response to the conductivity detection value exceeding the conductivity threshold, the maximum water replenishment amount is adjusted to perform rapid water replenishment.

[0008] In some embodiments, a four-stage rinsing process is adopted, and new water enters from the water inlet of the fourth-stage rinsing tank, and is rinsed countercurrently in the opposite direction of the strip running direction. The new water enters the third-stage, second-stage, and first-stage rinsing tanks in sequence through a step-by-step overflow method.

[0009] In some embodiments, automatically starting spraying and water replenishment based on the running status of the strip steel includes: When the unit is running, the rinse water pump is automatically turned on for spraying and water replenishment; When the unit stops running, the rinse water pump will be automatically turned off.

[0010] In some embodiments, the conductivity threshold is 25-40 μs / cm.

[0011] In some embodiments, the unit operating speed includes three stages, wherein: In the first stage, the minimum water replenishment amount is proportional to the unit operating speed; In the second stage, the minimum water replenishment amount is a fixed value; In the third stage, the minimum water replenishment amount is proportional to the unit operating speed.

[0012] In some embodiments, the relationship between the minimum water replenishment amount and the unit operating speed is: In the first stage, the running speed is 0~2m / min, and the minimum replenishment of rinsing water is 0~1m 3 / h; In the second stage, the running speed is 2~15m / min, and the minimum amount of rinse water is 1m 3 / h; In the third stage, the running speed is 15~75 m / min, and the minimum replenishment of rinsing water is 1~5 m 3 / h.

[0013] In some embodiments, the maximum water replenishment volume is 20-30 m 3 / h.

[0014] In some embodiments, the temperature of the rinsing water during rinsing is controlled to be 20-60°C.

[0015] Another aspect of the present invention provides a system for reducing the amount of rinsing water used in the continuous pickling process of steel strips, which is used to implement the above method and includes the following steps: Unit running roller table; Multi-stage rinsing tanks and multi-stage rinsing pumps are arranged adjacent to each other along the roller conveyor of the unit, and each rinsing tank is connected to a water pump; Conductivity detector, which is installed at the last rinsing tank to monitor the conductivity of the water in the rinsing tank; Flow meter: The flow meter is installed at the water inlet of the last rinse tank to monitor the water replenishment volume; PLC control system, the PLC control system is electrically connected to the unit's operating roller, water pump, conductivity detector and flow detector.

[0016] In some embodiments, the method further includes: a pH detector, which is disposed in the last rinsing tank and connected to the PLC control system.

[0017] The present invention has at least the following beneficial technical effects: 1. Spraying and water replenishment are only carried out when the strip steel in the process section is running, so as to avoid ineffective waste of rinsing water; 2. Automatic minimum water replenishment function reduces the amount of rinsing water while ensuring the quality of strip rinsing; 3. The minimum water replenishment volume is interlocked with the unit speed, automatically adapting to the running speed of the strip steel in the process section. The faster the speed, the greater the minimum water replenishment volume, ensuring that the strip steel can be cleaned while minimizing the use of rinse water. 4. When the rinsing water quality is abnormal, add water at the maximum amount to quickly replace the dirty water. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a schematic diagram of the relationship between the rinse water replenishment amount and the strip running speed provided by the present invention. DETAILED DESCRIPTION

[0020] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0021] The terms "including," "having," and any variations thereof in the present specification, claims, and accompanying drawings are intended to cover non-exclusive inclusions. The terms "first," "second," and the like in the present specification, claims, and accompanying drawings are used to distinguish between different items, not to describe a particular order. "Multiple" means two or more, unless otherwise expressly specified.

[0022] Furthermore, references herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0023] The main process of a continuous pickling process is typically pickling-rinsing-squeezing-drying. When metal strips pass through a continuous pickling line, a rinsing step is typically used to remove residual acid from the strip's surface, preventing it from adhering to the surface and causing corrosion. This is because, with the continuous advancement of industrialized production, the current metal strip pickling process is primarily continuous pickling, a process that offers advantages such as stable product quality and high efficiency. After pickling, residual acid remains on the strip's surface. Prolonged acid retention can cause persistent corrosion, typically manifesting as color shift, rust, or corrosion, thus affecting the strip's surface quality. Therefore, continuous pickling lines require a post-pickling process to remove residual acid from the strip's surface, known as a rinsing step. This rinsing step effectively dilutes and removes the residual acid by flushing the strip's surface with water, ultimately reducing the residual acid concentration to a level that prevents corrosion. Therefore, the rinsing process is necessary for the continuous pickling unit. Practice has proved that rinsing with water is economical, simple and reliable. However, the existing technology usually has problems such as frequent rinsing water replenishment and large water replenishment, which leads to increased production costs.

[0024] Therefore, the present invention proposes a method for reducing the amount of rinsing water used in the continuous pickling process section of strip steel. A multi-stage rinsing process is adopted, and a conductivity detector is set in the last-stage rinsing tank to detect the conductivity in real time. The operating status of the unit is interlocked with the rinsing water pump, and spraying and water replenishment are automatically started based on the operating status of the unit. The minimum water replenishment amount is set based on the operating speed of the unit. Water is replenished at the minimum water replenishment amount during operation. In response to the conductivity detection value exceeding the conductivity threshold, the maximum water replenishment amount is adjusted to perform rapid water replenishment.

[0025] Furthermore, a four-stage rinsing process is adopted. Fresh water enters the fourth-stage rinsing tank inlet and rinses in a countercurrent flow opposite to the direction of strip travel. Fresh water then flows sequentially into the third, second, and first-stage rinsing tanks via a step-by-step overflow system. This step-by-step overflow replenishment method effectively utilizes water resources and reduces fresh water consumption. Furthermore, as the quality of the rinse water gradually decreases at each stage, starting with high-purity ultrapure water and passing through each stage of the rinsing tank, a progressively finer rinsing of the metal strip is achieved, ensuring both effective rinsing and improved water resource utilization.

[0026] Specifically, the pickled metal strip enters the primary rinsing tank at a constant speed. In some embodiments, the speed is 5-15 m / min. The strip is immersed in the rinsing tank to an appropriate depth, generally ensuring full contact with the rinse water, covering approximately 80%-90% of its width. Countercurrent rinsing is employed, with fresh rinse water entering at one end of the tank and water containing a small amount of pickling residue exiting at the other. After the primary rinse, the strip enters the secondary rinsing tank directly. The strip's residence time in the secondary rinsing tank is relatively long, typically around 30-60 seconds, to more thoroughly remove any residual pickling solution from the surface. Countercurrent rinsing and appropriate agitation are also employed in the rinsing tank. The agitation device can be a spray device, spraying the strip from above. The spray pressure is controlled at approximately 0.2-0.5 MPa to ensure that the rinse water evenly irrigates the strip surface. After entering the tertiary rinsing tank, a combination of multi-stage spraying and immersion is employed. Spraying devices are installed above and below the rinsing tank, spraying the strip simultaneously from top to bottom, ensuring that all areas of the strip surface are thoroughly rinsed. The spray angle can be adjusted, generally at a 30-60 degree angle to the strip surface, to ensure that the rinse water effectively flushes the strip. Simultaneously, the strip is immersed in the rinsing tank for a period of approximately 40-80 seconds. The fourth-stage rinse uses ultrapure water as the rinse water. After the metal strip enters the fourth-stage rinse tank, it is primarily rinsed using a combination of immersion and gentle spraying. The soaking time can be around 60-120 seconds, allowing the ultrapure water to fully contact the strip surface, dissolving and removing the last trace impurities. The spraying device uses a more refined nozzle and a lower spray pressure of 0.1-0.3MPa, primarily to further clean the strip without damaging the surface.

[0027] Furthermore, automatically starting spraying and water replenishment based on the strip running status includes: When the unit is running, the rinse water pump is automatically turned on for spraying and water replenishment; When the unit stops running, the rinse water pump will be automatically turned off.

[0028] The unit operating speed includes three stages, among which, In the first stage, the minimum water replenishment amount is proportional to the unit operating speed; In the second stage, the minimum water replenishment amount is a fixed value; In the third stage, the minimum water replenishment amount is proportional to the unit operating speed.

[0029] Furthermore, the relationship between the minimum water replenishment amount and the unit operating speed is: In the first stage, the running speed is 0~2m / min, and the minimum replenishment of rinsing water is 0~1m 3 / h; In the second stage, the running speed is 2~15m / min, and the minimum amount of rinse water is 1m 3 / h; In the third stage, the running speed is 15~75 m / min, and the minimum replenishment of rinsing water is 1~5 m 3 / h.

[0030] Furthermore, the maximum water replenishment is 20~30m 3 / h.

[0031] Furthermore, the rinse water temperature is controlled to be between 20 and 60°C during rinsing. Specifically, the water temperature is generally maintained at room temperature (20-30°C) during the first rinse, the water temperature can be appropriately increased to approximately 30-40°C during the second rinse, the water temperature is maintained at 40-50°C during the third rinse, and the ultrapure water temperature can be controlled at 50-60°C during the fourth rinse to achieve the best rinsing effect.

[0032] Another aspect of the present invention provides a system for reducing the amount of rinsing water used in a continuous pickling process of steel strips, which is used to implement the above method, comprising: Unit running roller table; Multi-stage rinsing tanks and multi-stage rinsing pumps are arranged adjacent to each other along the roller conveyor of the unit, and each rinsing tank is connected to a water pump; Conductivity detector, which is installed at the last rinsing tank to monitor the conductivity of the water in the rinsing tank; Flow meter: The flow meter is installed at the water inlet of the last rinse tank to monitor the water replenishment volume; PLC control system, the PLC control system is electrically connected to the unit's operating roller, water pump, conductivity detector and flow detector.

[0033] Furthermore, the system also includes: a pH detector, which is installed in the last-stage rinsing tank and connected to the PLC control system. The detection data of the pH detector can be fed back to the PLC control system. If an abnormal pH value is detected, the control system can automatically adjust the rinsing parameters. For example, when the pH value is lower than 7, the control system can extend the rinsing time, increase the flow rate of ultrapure water, or enhance the intensity of the spray. Conversely, if the pH value remains within the appropriate range, it indicates that the rinsing process is normal, and the control system can continue to operate according to the preset program, thereby realizing the automation and precision control of the rinsing process, improving production efficiency and product quality.

[0034] The present invention will be further explained below with reference to specific embodiments.

[0035] A four-stage rinsing process is adopted, and a conductivity detector is set in the four-stage rinsing tank to detect conductivity in real time. The unit operation status is interlocked with the rinsing water pump, and spraying and water replenishment are automatically started based on the unit operation status. The minimum water replenishment amount is set based on the unit operation speed. Water is replenished at the minimum water replenishment amount during operation. In response to the conductivity detection value exceeding the conductivity threshold, the maximum water replenishment amount is adjusted for rapid water replenishment.

[0036] The unit's operating speed includes three stages. In the first stage, the operating speed is 0~2m / min, and the minimum rinsing water replenishment volume is 0~1m 3 / h; In the second stage, the running speed is 2~15m / min, and the minimum amount of rinse water is 1m 3 / h; In the third stage, the running speed is 15~75 m / min, and the minimum replenishment of rinsing water is 1~5 m 3 / h.

[0037] The corresponding relationship between the specific operating speed and the minimum amount of rinse water replenishment is shown in Table 1.

[0038] When the rinse water quality is abnormal (conductivity exceeds the standard), water is replenished at a maximum rate of 20 cubic meters per hour to quickly replace the dirty water. After the water quality returns to normal, the minimum replenishment rate is restored.

[0039] Table 1 Relationship between the running speed of the strip steel in the process section and the minimum replenishment amount of rinsing water

[0040] The method of the present invention can greatly reduce the amount of rinsing water while ensuring the quality of strip rinsing. The average amount of rinsing water before improvement is 10.0m 3 / h, and the average rinsing water consumption after improvement is 5.0 m 3 / h, reducing the production cost of the pickling unit and thus improving the efficiency of the enterprise.

[0041] The above are exemplary embodiments disclosed in the present invention, but it should be noted that various changes and modifications may be made without departing from the scope of the embodiments disclosed in the claims. The functions, steps and / or actions of the method claims according to the disclosed embodiments described herein do not need to be performed in any particular order. In addition, although the elements disclosed in the embodiments of the present invention may be described or required in individual form, they may also be understood as multiple unless expressly limited to the singular.

[0042] It should be understood that, as used herein, the singular forms "a" and "an" are intended to include the plural forms as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" is intended to include any and all possible combinations of one or more of the associated listed items.

[0043] The serial numbers of the embodiments disclosed in the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0044] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to limit the scope of the disclosure of the present invention (including the claims) to these examples. Within the spirit of the present invention, the technical features of the above embodiments or different embodiments may be combined, and many other variations exist in different aspects of the above embodiments, which are not provided in detail for the sake of clarity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. 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 method for reducing the amount of rinsing water used in a continuous pickling process section of steel strip, characterized in that: A multi-stage rinsing process is adopted, and a conductivity detector is set in the last-stage rinsing tank to detect conductivity in real time. The unit operation status is interlocked with the rinsing water pump, and spraying and water replenishment are automatically started based on the unit operation status. The minimum water replenishment amount is set based on the unit operation speed. Water is replenished with the minimum water replenishment amount during operation. In response to the conductivity detection value exceeding the conductivity threshold, the maximum water replenishment amount is adjusted to perform rapid water replenishment.

2. The method for reducing the amount of rinsing water used in the continuous pickling process of steel strip according to claim 1, characterized in that: A four-stage rinsing process is adopted. New water enters from the water inlet of the fourth-stage rinsing tank and is rinsed in the opposite direction of the strip running direction. The new water enters the third-stage, second-stage and first-stage rinsing tanks in sequence through a step-by-step overflow method.

3. The method for reducing the amount of rinsing water used in the continuous pickling process of steel strip according to claim 1, characterized in that: Automatically start spraying and water replenishment based on the strip running status, including: When the unit is running, the rinse water pump is automatically turned on for spraying and water replenishment; When the unit stops running, the rinsing water pump is automatically turned off.

4. The method for reducing the amount of rinsing water used in the continuous pickling process of steel strip according to claim 1, characterized in that: The conductivity threshold is 25-40 μs / cm.

5. The method for reducing the amount of rinsing water used in the continuous pickling process of steel strip according to claim 1, characterized in that: The unit operating speed includes three stages, among which, In the first stage, the minimum water replenishment amount is proportional to the operating speed of the unit; In the second stage, the minimum water replenishment amount is a fixed value; In the third stage, the minimum water replenishment amount is proportional to the operating speed of the unit.

6. The method for reducing the amount of rinsing water used in the continuous pickling process of steel strip according to claim 5, characterized in that: The relationship between the minimum water replenishment amount and the operating speed of the unit is: In the first stage, the running speed is 0~2m / min, and the minimum replenishment of rinsing water is 0~1m 3 / h; In the second stage, the running speed is 2~15m / min, and the minimum amount of rinsing water is 1m 3 / h; In the third stage, the running speed is 15~75 m / min, and the minimum replenishment of rinsing water is 1~5 m 3 / h.

7. The method for reducing the amount of rinsing water used in the continuous pickling process of steel strip according to claim 1, characterized in that: The maximum water replenishment volume is 20~30m 3 / h.

8. The method for reducing the amount of rinsing water used in the continuous pickling process of steel strip according to claim 1, characterized in that: Control the rinsing water temperature at 20~60℃ during rinsing.

9. A system for reducing the amount of rinsing water used in a continuous pickling process of steel strips, for implementing the method according to any one of claims 1 to 8, characterized in that: include: Unit running roller table; Multi-stage rinsing tanks, the multi-stage rinsing pumps are arranged adjacent to each other in sequence along the running roller of the unit, and each of the rinsing tanks is connected to a water pump; A conductivity detector is provided at the last rinsing tank to monitor the conductivity of the water in the rinsing tank; A flow meter is provided at the water inlet of the last rinse tank to monitor the amount of water replenished; A PLC control system is electrically connected to the unit's operating roller, water pump, conductivity detector, and flow detector.

10. The system for reducing rinsing water consumption in the continuous pickling process of steel strip according to claim 9, characterized in that: Also includes: A pH detector is provided in the last-stage rinsing tank and is connected to the PLC control system.

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