A strip cleaning system and method

Abstract

The present application provides a strip steel cleaning system and method, the system comprises an inlet tension roller, a modular cleaning unit, a rinsing unit and an outlet tension roller arranged in sequence along the running direction of the strip steel, the modular cleaning unit comprises a cleaning agent atomizing spray beam, a wetting roller, an active excitation device and a spray washing beam, a medicament assembly is connected to the modular cleaning unit, and a rinsing water assembly is connected to the spray washing beam and the rinsing unit. The present application combines the characteristics of strip steel surface contaminants, fully utilizes the high catalytic activity of the micro-nano iron powder on the surface of the strip steel and the characteristics that the high-efficiency catalytic active agent can decompose grease after the iron powder is dissolved in the pickling medium to clean the strip steel surface contaminants, cancels the high energy consumption and the large-area wet system of the conventional cleaning process, has no alkali-containing wastewater and hazardous waste product discharge, and only needs to wet the surface of the strip steel and react on the upper and lower surfaces of the strip steel, without soaking in the medium, thereby reducing the production cost and improving the cleaning quality of the strip steel surface.

Description

Technical Field

[0001] This invention belongs to the field of strip steel production technology, specifically relating to a strip steel cleaning system and method. Background Technology

[0002] The surface quality of strip steel is one of the key factors affecting product performance improvement. After cold rolling, the surface of strip steel is covered with rolling oil, machine oil, iron powder, etc. If not cleaned properly, it will affect subsequent processing. In particular, if the iron powder is not removed thoroughly, it can easily lead to nodules on the furnace rolls, ultimately resulting in a decrease in the surface quality of the strip steel and scratches on the strip steel.

[0003] High-strength steel, stainless steel, and ultra-thin silicon steel have low rolling oil content, thin ink thickness, and low iron powder content on their surfaces. However, the strips are thin, and the unit speed is high. Conventional chemical cleaning + electrolytic cleaning + physical rinsing combinations require significant tension, which can easily lead to strip breakage and shutdown during high-speed cleaning. Currently, some continuous annealing furnaces use open flame burners for heating, which have a certain tolerance to oil stains on the strip surface. At the same time, alkaline cleaning is effective at removing oil stains, but its ability to remove iron powder is poor, which can easily cause the furnace rolls to scratch the strip. Furthermore, alkaline cleaning relies on a large amount of strongly alkaline medium to dissolve and peel off contaminants from the strip surface, resulting in a large circulation system and a large amount of hazardous waste sludge to be treated. Summary of the Invention

[0004] The purpose of this invention is to provide a strip steel cleaning system that can at least solve some of the defects existing in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A strip steel cleaning system includes an inlet tension roller, a modular cleaning unit, a rinsing unit, and an outlet tension roller arranged sequentially along the strip steel running direction. The modular cleaning unit includes a cleaning agent atomizing spray beam for wetting the upper and lower surfaces of the strip steel, a wetting roller for covering the strip steel surface with cleaning agent, an activation device for activating a catalytic reaction, and a spray beam for cleaning the strip steel surface after the catalytic reaction, all arranged sequentially along the strip steel running direction. A reagent assembly for supplying cleaning agent to each of the cleaning agent atomizing spray beams is connected to the modular cleaning unit. A rinsing water assembly for supplying rinsing water to the spray beams and the rinsing unit for cleaning the strip steel surface is connected to them.

[0007] Furthermore, the modular cleaning unit is provided in multiple units, and the multiple modular cleaning units are arranged in series along the running direction of the strip steel.

[0008] Furthermore, the inlet tension roller and the outlet tension roller are respectively provided with an inlet cleanliness detection mechanism and an outlet cleanliness detection mechanism for detecting the surface cleanliness of the strip steel, and the inlet cleanliness detection mechanism and the outlet cleanliness detection mechanism are interlocked with the cleaning agent concentration of the agent component, the power of the activation device, and the number of modular cleaning units put into operation.

[0009] Furthermore, heating and drying devices are provided between the inlet tension roller and the modular cleaning unit, and between the rinsing unit and the outlet tension roller.

[0010] Furthermore, the activation device is plasma, laser, or ultraviolet light.

[0011] Furthermore, the cleaning agent comprises the following components by mass percentage: 3-15% strong acid, 0.5-8% surfactant, 0.5-5% active agent, and the balance being water; wherein the strong acid is at least one of hydrochloric acid, hydrofluoric acid, and sulfuric acid, the surfactant is at least one of hydrogen peroxide and sodium hypochlorite, and the active agent is an aliphatic polyoxyethylene ether; the components of the cleaning agent are sprayed onto the surface of the strip steel, either separately or in mixture.

[0012] Furthermore, the reagent assembly includes a chemical reagent tank, an active agent tank, and a mixer. The outlet of the chemical reagent tank is connected to the inlet of the mixer via a delivery pump. The active agent tank is connected to the mixer. The outlet of the mixer is connected to each of the cleaning agent atomizing spray beams. The mixer is a Venturi pipe mixer.

[0013] Furthermore, the rinsing water in each of the modular cleaning and rinsing units overflows back into the chemical reagent tank.

[0014] In addition, the present invention also provides a strip steel cleaning method, wherein the above-mentioned strip steel cleaning system specifically includes the following process:

[0015] The strip steel is driven sequentially into the modular cleaning unit and rinsing unit by the inlet tension roller and the outlet tension roller for cleaning and rinsing.

[0016] When the strip steel passes through the modular cleaning unit, the upper and lower surfaces of the strip steel are first wetted by the cleaning agent atomizing spray beam, and then the cleaning agent is covered to the entire surface of the strip steel by the wetting roller. After that, the strip steel enters the activation device to carry out the catalytic reaction. After the reaction, the surface of the strip steel after the catalytic reaction is cleaned by the spray beam.

[0017] Furthermore, the surface cleanliness of the strip is detected at one end of the exit tension roller, and the detected value is compared with the target set value. The difference between the target set value and the exit cleanliness detection value is set as d.

[0018] When d > 10%, the program will increase the number of modular cleaning units, while other parameters remain unchanged.

[0019] When 4 < d ≤ 10%, maintain the number of modular cleaning units and increase the power density of each modular cleaning unit;

[0020] When 0 < d ≤ 4%, stabilize the number and power density of modular cleaning units, increase the concentration of cleaning agent, and increase the spray pressure of each modular cleaning unit and rinsing unit.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] The strip steel cleaning system provided by this invention combines the characteristics of surface contaminants on strip steel, making full use of the high catalytic activity of micro-nano-level iron powder on the strip steel surface and its characteristic of still having a highly efficient catalytic activity to decompose grease after dissolution under the action of pickling medium to clean surface contaminants on strip steel. It eliminates the high energy consumption and large footprint of conventional cleaning processes, and there is no discharge of alkaline wastewater or hazardous waste products. Moreover, it only wets the surface of the strip steel and reacts efficiently on its upper and lower surfaces, without the need for soaking or spraying in the main medium, thus reducing production costs and improving the cleaning quality of strip steel surface.

[0023] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the strip cleaning system in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the modular cleaning unit in an embodiment of the present invention.

[0026] Explanation of reference numerals in the attached drawings: 1. Inlet cleanliness detection mechanism; 2. Strip steel; 3. Inlet tension roller; 4. Inlet heating and drying device; 5. Modular cleaning unit; 6. Rinsing unit; 7. Outlet heating and drying device; 8. Outlet tension roller; 9. Outlet cleanliness detection mechanism; 10. Mixer; 11. Activator tank; 12. Chemical reagent tank; 13. Rinse water tank; 14. Cleaning agent atomizing spray beam; 15. Wetting roller; 16. Activation device; 17. Spray beam. Detailed Implementation

[0027] 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.

[0028] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection", and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, an abutting connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0031] Analysis of surface contaminants on steel strips reveals that they primarily consist of micro / nano-sized iron powder and grease complexes or coatings. The micro / nano-sized iron powder itself exhibits the characteristic of rapidly decomposing grease under the excitation of a high-energy-density device. Based on this, this embodiment designs a steel strip cleaning system, such as... Figure 1 and Figure 2 As shown, the system specifically includes an inlet tension roller 3, a modular cleaning unit 5, a rinsing unit 6, and an outlet tension roller 8 arranged sequentially along the running direction of the strip 2. The modular cleaning unit 5 includes a cleaning agent atomizing spray beam 14 for wetting the upper and lower surfaces of the strip 2, a wetting roller 15 for covering the surface of the strip 2 with cleaning agent, an activity activation device 16 for activating the catalytic reaction, and a spray beam 17 for cleaning the surface of the strip 2 after the catalytic reaction. The modular cleaning unit 5 is connected to a reagent assembly that provides cleaning agent to each of the cleaning agent atomizing spray beams 14. The spray beam 17 and the rinsing unit 6 are connected to a rinsing water assembly that provides rinsing water to clean the surface of the strip 2.

[0032] The cleaning agent comprises the following components by mass percentage: 3-15% strong acid, 0.5-8% activator, 0.5-5% surfactant, and the balance being water; wherein the strong acid is at least one of hydrochloric acid, hydrofluoric acid, and sulfuric acid; the activator is at least one of hydrogen peroxide and sodium hypochlorite; and the surfactant is an aliphatic polyoxyethylene ether. During operation, the inlet tension roller 3 and the outlet tension roller 8 provide power for the movement of the strip steel 2. After passing through the inlet tension roller 3, the strip steel 2 enters the cleaning process section. Upon passing through the modular cleaning unit 5, the upper and lower surfaces of the strip steel 2 are first wetted by the cleaning agent atomizing spray beam 14, and then the cleaning agent covers the entire surface of the strip steel 2 by the wetting roller 15. The strip steel 2 then enters the activation device 16 for a catalytic reaction. After the reaction, the surface of the strip steel 2 is cleaned by the spray beam 17. The components of the cleaning agent are sprayed onto the surface of the strip steel 2 individually or in mixture. In this embodiment, the characteristics of surface contaminants on strip steel 2 are taken into account. The high catalytic activity of micro-nano-sized iron powder on the surface of strip steel 2 and its characteristic of still having a high-efficiency catalytic activity to decompose grease after dissolution under the action of pickling medium are fully utilized to clean the surface contaminants of strip steel 2. This eliminates the high energy consumption and large footprint of conventional cleaning processes, and there is no discharge of alkaline wastewater or hazardous waste products. Furthermore, it only wets the surface of strip steel 2 and reacts efficiently on its upper and lower surfaces, without the need for soaking or spraying in the medium body, which reduces production costs. It also avoids problems such as strip steel deviation and unstable tension control accuracy caused by conventional multi-stage brushing. It avoids the unsatisfactory removal effect of conventional alkaline cleaning media on the surface of strip steel, thus improving the surface cleaning quality of strip steel.

[0033] Specifically, the activation device 16 can employ, but is not limited to, high-energy-density devices such as plasma, laser, or ultraviolet light. The energy density can be adjusted according to actual needs. Its specific structure is existing technology and will not be described in detail here. Under high-energy excitation, the micro / nano-sized iron powder on the surface of the steel strip 2 can promote the decomposition of hydrogen peroxide / hypochlorous acid, generating ·OH free radicals / ClO· free radicals. These free radicals have strong oxidizing properties and can attack the C=C double bonds in oil molecules, oxidizing them into small-molecule carboxylic acids or carbon dioxide. For example, in a hypochlorous acid system, the micro / nano-sized iron powder can... The reduction reaction rate is increased, generating ClO· free radicals. Although their oxidation potential is slightly lower than that of ·OH, their stability is higher, making them suitable for long-term decomposition of long-chain hydrocarbon oils. Preferably, the distance between the activity activation device 16 and the strip steel 2 is adjustable, and the adjustment method can be such as a screw jack.

[0034] In a preferred embodiment, multiple modular cleaning units 5 can be designed, with multiple modular cleaning units 5 arranged in series along the running direction of the strip steel 2, and each modular cleaning unit 5 can be opened and closed independently and can be moved out of the production line; therefore, in this embodiment, the number of modular cleaning units 5 put into operation and the intensity of each modular cleaning unit 5 can be adaptively controlled and adjusted according to different incoming materials and surface cleanliness requirements of the strip steel 2 at the inlet and outlet, thereby reducing energy consumption while ensuring the surface cleanliness quality of the strip steel 2.

[0035] Furthermore, the inlet tension roller 3 and the outlet tension roller 8 are respectively provided with an inlet cleanliness detection mechanism 1 and an outlet cleanliness detection mechanism 9 for detecting the surface cleanliness of the strip steel 2. The inlet cleanliness detection mechanism 1 and the outlet cleanliness detection mechanism 9 are interlocked with the cleaning agent concentration of the reagent component, the power of the activation device 16, and the number of modular cleaning units 5 in operation. Specifically, in some embodiments, the difference between the target set value of the surface cleanliness of the strip steel 2 and the outlet cleanliness detection value is designed as d, and the following adjustment methods are followed: when d > 10%, the program is started to increase the number of modular cleaning units 5, while other parameters remain unchanged; when 4 < d ≤ 10%, the number of modular cleaning units 5 is maintained, and the power density of each modular cleaning unit 5 is increased; when 0 < d ≤ 4%, the number and power density of modular cleaning units 5 are stabilized, the concentration of the cleaning agent is increased, and the spraying pressure of each modular cleaning unit 5 and the rinsing unit 6 is increased.

[0036] In the optimized implementation, an inlet heating and drying device 4 is provided between the inlet tension roller 3 and the modular cleaning unit 5. Before entering the cleaning process section, the strip steel 2 is heated to 40-60℃ by the heating and drying device to optimize the surface condition of the strip steel 2 and improve the cleaning conditions, providing a more stable environment for the subsequent cleaning process. Specifically, on the one hand, heating the strip steel 2 can evaporate the surface moisture of the strip steel 2, ensuring that the surface of the strip steel 2 is dry and reducing the risk of dilution of the subsequent cleaning agent. The dry surface of the strip steel 2 is more conducive to the uniform coverage of the subsequent cleaning agent. On the other hand, the contaminants (such as grease) on the surface of the strip steel 2 will soften at a temperature of 40-60℃, reducing their bonding force with the substrate of the strip steel 2, which is conducive to the efficient penetration and removal of contaminants by the subsequent cleaning agent. In addition, if the strip steel 2 enters the subsequent high-energy-density device directly from room temperature for catalytic reaction, it may cause local deformation or surface micro-cracks due to thermal stress. However, after preheating it to 40-60℃ before the cleaning process section, the temperature gradient is reduced, reducing the risk of thermal stress.

[0037] Furthermore, an outlet heating and drying device 7 is provided between the rinsing unit 6 and the outlet tension roller 8. This heating and drying device, located after the cleaning process section, is used to heat and dry the moisture on the surface of the strip 2 after cleaning, facilitating subsequent processing.

[0038] In this embodiment, the components of the cleaning agent can be sprayed separately onto the strip surface, or the components can be mixed and then sprayed onto the strip surface. When spraying the mixture, it is preferable to use an acidic component to encapsulate the surfactant.

[0039] One specific embodiment of the agent component supplying the cleaning agent during mixed spraying is as follows: Figure 1 As shown, the reagent assembly includes a chemical reagent tank 12, an surfactant tank 11, and a mixer 10. The chemical reagent (i.e., the strong acid component in the cleaning agent) is added to the chemical reagent tank 12, and the surfactant (i.e., the surfactant and surfactant components in the cleaning agent) is added to the surfactant tank 11. The cleaning agent components in the chemical reagent tank 12 and the surfactant tank 11 are prepared into solutions of corresponding concentrations according to the design concentration. The outlet of the chemical reagent tank 12 is connected to the inlet of the mixer 10 via a transfer pump. The surfactant tank 11 and the mixer 10... The mixer 10 is connected to the outlet of each of the cleaning agent atomizing spray beams 14. The mixer 10 is preferably a Venturi pipe mixer. In this way, during the process of the chemical reagent being transported from the chemical reagent tank 12 to each modular cleaning unit 5 via a delivery pump, the mixer 10 entrains a certain concentration of surfactant and mixes it with the chemical reagent before delivering it to the cleaning agent atomizing spray beams 14 of each modular cleaning unit 5. The cleaning agent atomizing spray beams 14 preferably spray the cleaning agent onto the upper and lower surfaces of the strip steel 2 in the form of atomizing nozzles to wet the upper and lower surfaces of the strip steel 2.

[0040] In one specific implementation, the rinsing water used for spraying and rinsing the surface of the strip steel 2 after the catalytic reaction in the spray beam 17 of each modular cleaning unit 5 and the rinsing unit 6 is demineralized water; specifically, the rinsing water assembly includes a rinsing water tank 13 for holding demineralized water, and the demineralized water in the rinsing water tank 13 is transported to the spray beam 17 and the rinsing unit 6 at the end of each modular cleaning unit 5 by a demineralized water pump.

[0041] In some embodiments, the rinsing unit 6 preferably uses a 2-3 stage rinsing tank to rinse the surface of the strip steel 2, thereby further improving the surface cleanliness of the strip steel 2.

[0042] Preferably, the rinsing water in each of the modular cleaning units 5 and rinsing units 6 is designed to overflow back into the chemical reagent tank 12; wherein the chemical reagent is prepared by mixing the overflowing rinsing water with the original chemical reagent solution, and rinsing water is added through an automatic valve. The automatic valve is interlocked with the liquid level of the chemical reagent tank 12. When the liquid level of the chemical reagent tank 12 is low or the concentration is high, the automatic valve opens to add overflowing rinsing water. The rinsing water tank 13 is transported to the end spray beam 17 of each modular cleaning unit 5 and the rinsing unit 6 through a demineralized water pump to achieve multi-stage overflow rinsing.

[0043] Further optimization involves equipping the modular cleaning unit 5, rinsing unit 6, and circulation tanks (i.e., chemical reagent tank 12 and rinsing water tank 13) with exhaust vents that connect to the exhaust gas treatment system.

[0044] Experiments have shown that the surface reflectivity of the strip steel cleaned using the strip steel cleaning system of this embodiment can reach over 95%, and the residual oil content on the strip steel surface is <6mg / m². 2 Residual iron content <4mg / m 2 It is fully applicable to the cleaning process of high-speed cold rolling continuous annealing production lines.

[0045] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A strip steel cleaning system, characterized in that: The device includes an inlet tension roller, a modular cleaning unit, a rinsing unit, and an outlet tension roller arranged sequentially along the strip running direction. The modular cleaning unit includes a cleaning agent atomizing spray beam for wetting the upper and lower surfaces of the strip, a wetting roller for covering the strip surface with cleaning agent, an activation device for activating a catalytic reaction, and a spray beam for cleaning the strip surface after the catalytic reaction, all arranged sequentially along the strip running direction. The modular cleaning unit is connected to a reagent assembly that provides cleaning agent to each of the cleaning agent atomizing spray beams. The spray beam and the rinsing unit are connected to a rinsing water assembly that provides rinsing water to clean the strip surface. The cleaning agent comprises the following components by mass percentage: 3-15% strong acid, 0.5-8% activator, 0.5-5% surfactant, and the balance being water; wherein the strong acid is at least one of hydrochloric acid, hydrofluoric acid, and sulfuric acid, the activator is at least one of hydrogen peroxide and sodium hypochlorite, and the surfactant is an aliphatic polyoxyethylene ether; the components of the cleaning agent are sprayed onto the surface of the strip steel, either individually or in mixture; the activation device is used to activate the catalytic activity of the micro-nano-sized iron powder adhering to the surface of the strip steel, so that the iron powder catalyzes the decomposition of the activator in the cleaning agent to generate free radicals, which are used to oxidize and decompose the oily contaminants on the surface of the strip steel.

2. The strip steel cleaning system as described in claim 1, characterized in that: The modular cleaning unit is provided in multiple units, and the multiple modular cleaning units are arranged in series along the running direction of the strip steel.

3. The strip steel cleaning system as described in claim 2, characterized in that: The inlet tension roller and the outlet tension roller are respectively provided with an inlet cleanliness detection mechanism and an outlet cleanliness detection mechanism for detecting the surface cleanliness of the strip steel. The inlet cleanliness detection mechanism and the outlet cleanliness detection mechanism are interlocked with the cleaning agent concentration of the agent component, the power of the activation device, and the number of modular cleaning units put into operation.

4. The strip steel cleaning system as described in claim 1, characterized in that: Heating and drying devices are provided between the inlet tension roller and the modular cleaning unit, and between the rinsing unit and the outlet tension roller.

5. The strip steel cleaning system as described in claim 1, characterized in that: The activation device is plasma, laser, or ultraviolet light.

6. The strip steel cleaning system as described in claim 1, characterized in that: The pharmaceutical assembly includes a chemical reagent tank, an active agent tank, and a mixer. The outlet of the chemical reagent tank is connected to the inlet of the mixer via a delivery pump. The active agent tank is connected to the mixer. The outlet of the mixer is connected to each of the cleaning agent atomizing spray beams. The mixer is a Venturi pipe mixer.

7. The strip cleaning system as described in claim 6, characterized in that: The rinsing water in each of the modular cleaning and rinsing units overflows back into the chemical reagent tank.

8. A method for cleaning steel strip, characterized in that: The strip cleaning system according to any one of claims 1-7 specifically includes the following process: The strip steel is driven sequentially into the modular cleaning unit and rinsing unit by the inlet tension roller and the outlet tension roller for cleaning and rinsing. When the strip steel passes through the modular cleaning unit, the upper and lower surfaces of the strip steel are first wetted by the cleaning agent atomizing spray beam, and then the cleaning agent is covered to the entire surface of the strip steel by the wetting roller. After that, the strip steel enters the activation device to carry out the catalytic reaction. After the reaction, the surface of the strip steel after the catalytic reaction is cleaned by the spray beam.

9. The strip steel cleaning method as described in claim 8, characterized in that: The surface cleanliness of the strip is detected at one end of the exit tension roller, and the detected value is compared with the target set value. The difference between the target set value and the exit cleanliness detection value is set as d. When d > 10%, the program will increase the number of modular cleaning units, while other parameters remain unchanged. When 4% < d ≤ 10%, maintain the number of modular cleaning units and increase the power density of each modular cleaning unit; When 0 < d ≤ 4%, stabilize the number and power density of modular cleaning units, increase the concentration of cleaning agent, and increase the spray pressure of each modular cleaning unit and rinsing unit.

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