Post-plating cooling process and equipment

Abstract

The present invention relates to a post-plating cooling process and device, and belongs to the technical field of continuous annealing treatment. The process comprises the following steps: preliminary atomization: high-pressure water is initially atomized by the action of a gauze; mixing: supercritical fluid is uniformly mixed with the initially atomized droplets through the uniform flow field of the gauze; gauze atomization: the mixed droplets are broken again by the action of the gauze to obtain droplets with smaller particle size and more uniform distribution; explosive atomization: in the process of droplets being ejected through the gauze and then broken again, the supercritical fluid expands to obtain droplets with smaller particle size and more uniform particle size. The present invention realizes multiple atomization of droplets by combining a supercritical fluid and a hydrophobic gauze, thereby obtaining a spray with small droplet size and uniform particle size distribution. The present invention realizes uniform distribution of water and supercritical fluid by combining a narrow slit with the gauze, thereby improving the uniformity of spray distribution, and the channel gauze also plays a filtering role. The present invention reduces the evaporation temperature difference of the droplets by increasing the water temperature, which is conducive to the phase change of the droplets.

Description

Technical Field

[0001] The invention belongs to the technical field of continuous annealing treatment and relates to a post-plating cooling process and device. Background Art

[0002] In the post-plating treatment of steel strip, post-plating cooling is a crucial process step, significantly impacting product quality. With the increasing adoption of thick plate products, post-plating cooling requirements are becoming increasingly stringent, demanding both high cooling rates and high cooling uniformity. Currently, air cooling is no longer sufficient for thick plate cooling, but mist cooling remains a viable solution, and its application is growing.

[0003] There are multiple approaches to mist cooling, each with its own advantages and disadvantages. One approach involves placing nozzles across the width of the strip. Droplet parameters are heavily dependent on the performance of the atomizing nozzles. Because the strip dimensions are approximately an order of magnitude larger than the range of action of a single atomizing nozzle, multiple groups of nozzles are required across the strip width. Droplets from different groups of nozzles interact and overlap, leading to a high degree of interdependence among different devices in the system and a relatively complex system. Furthermore, uneven mist cooling can be easily caused by installation errors and flow distribution issues. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a post-plating cooling process and device, which utilizes the expansion of the fluid volume by hundreds or even thousands of times caused by the rapid release of pressure of supercritical fluid in a short period of time, and cooperates with hydrophobic gauze to achieve multiple atomization of droplets, so as to obtain a spray with small droplet size and uniform particle size distribution to cool the strip after plating.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A post-plating cooling process comprises the following steps:

[0007] (1) Initial atomization: High-pressure water is initially atomized through the mesh;

[0008] (2) Mixing: The supercritical fluid is uniformly mixed with the droplets initially atomized in step (1) through a uniform flow field of the gauze mesh;

[0009] (3) Gauze atomization: The droplets mixed in step (2) are broken up again by the gauze to obtain droplets with smaller particle size and more uniform distribution;

[0010] (4) Explosive atomization: In the process of the droplets being ejected through the gauze and then broken up again in step (3), the supercritical fluid expands to achieve "explosive atomization", obtaining droplets with smaller and more uniform particle sizes.

[0011] Optionally, the supercritical fluid is an antioxidant.

[0012] Optionally, the supercritical fluid is carbon dioxide.

[0013] Optionally, the pressure of the high-pressure water is higher than the critical pressure of the supercritical fluid; the temperature of the high-pressure water is higher than the critical temperature of the supercritical fluid.

[0014] A post-plating cooling device for the above-mentioned post-plating cooling process includes a water channel and a supercritical fluid channel, wherein the water channel is arranged with a water inlet, a first gauze, and a water outlet along the flow direction of high-pressure water; the supercritical fluid channel is arranged with a supercritical fluid inlet, a second gauze, and a supercritical fluid outlet along the flow direction of supercritical liquid, the water outlet and the supercritical fluid outlet merge to form a device outlet, and a third gauze is provided on the device outlet.

[0015] Optionally, a water flow channel is formed between the first gauze and the water outlet, and the projection of the second gauze on the water channel is located within the water flow channel.

[0016] Optionally, there are two supercritical flow fluid channels, which are symmetrically arranged on both sides of the water channel.

[0017] Optionally, the water outlet and the supercritical liquid outlet form an angle of 15° to 65°.

[0018] Optionally, the water outlet and the supercritical outlet are in the form of single-point circular holes or ellipses, and are arranged in front of the third gauze along the fluid flow direction.

[0019] Optionally, the third gauze is a plain gauze with a mesh count of 30 to 160, the gauze is hydrophobically treated, and the number of layers of the first gauze and the second gauze is 1 to 3.

[0020] The beneficial effects of the present invention are:

[0021] 1. The present invention adopts a method combining supercritical fluid and hydrophobic gauze to achieve multiple atomization of droplets, thereby obtaining a spray with small droplet size and uniform particle size distribution.

[0022] 2. The supercritical fluid used in the present invention is a substance with an antioxidant effect, and thus can slow down the surface oxidation of the steel strip caused by spraying.

[0023] 3. The present invention achieves uniform distribution of water and supercritical fluid by combining narrow slits with gauze, thereby improving the uniformity of spray distribution along the width direction. The channel gauze not only redistributes the fluid, but also plays a filtering role, which can effectively increase the life of the device.

[0024] 4. The present invention reduces the evaporation temperature difference of the droplets by increasing the water temperature, which is beneficial to the phase change of the droplets and improves the cooling and heat exchange performance of the mist.

[0025] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0027] Figure 1 Schematic diagram of the device structure of the present invention;

[0028] Figure 2 for Figure 1 A magnified view of area A;

[0029] Figure 3 This is a structural diagram of the third gauze.

[0030] Reference numerals: third gauze 1 , second gauze 2 , first gauze 3 , supercritical fluid inlet 4 , water inlet 5 , water outlet 6 , supercritical fluid outlet 7 , outlet plate 8 . DETAILED DESCRIPTION

[0031] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0032] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0033] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0034] See also Figures 1 to 3 In this embodiment, the post-plating cooling process of the present invention is explained in combination with a post-plating cooling device. A post-plating cooling device includes a third gauze 1, a second gauze 2, a first gauze 3, a supercritical fluid inlet 4, a water inlet 5, a water outlet 6, a supercritical fluid outlet 7, and an outlet plate 8; wherein the water inlet 5, the first gauze 3 and the water outlet 6 are connected in sequence; wherein the supercritical fluid inlet 4, the second gauze 2 and the supercritical fluid outlet 7 are connected in sequence; wherein the water outlet 6, the supercritical fluid outlet 7, the third gauze 1 and the outlet plate 8 constitute the device outlet structure, and the water outlet 6, the supercritical fluid outlet 7 and the outlet plate 8 constitute an outlet structure similar to the shape of a toad's mouth, which is used to obtain a fan-shaped spray.

[0035] like Figure 2 As shown, the water outlet 6 and the supercritical fluid outlet 7 form a certain angle, ranging from 15 to 65 degrees. The purpose is to mix the two fluids evenly, thereby laying the foundation for obtaining small and evenly distributed droplets. The water outlet 6 and the supercritical fluid outlet 7 are in the form of single-point circular holes or ellipses and are arranged before the third gauze 1. Assuming the width of the cooling device is 1.8m, 20 to 40 groups of outlets 6 and supercritical fluid outlets 7 are arranged along the width direction. In this case, the water flow rate of the cooling device is 150 to 450 L / h, and the corresponding supercritical fluid flow rate is 600 to 1800 L / h.

[0036] High-pressure water of 4 to 15 MPa at about 40°C (the pressure is selected according to the critical pressure of the supercritical fluid) enters from the water inlet 5, then passes through the first gauze 3, and is evenly sprayed out from the water outlet 6 evenly distributed in the width direction under the action of the first gauze 3. In the process of spraying from the small circular hole or the elliptical mouth, the liquid is initially broken into droplets, which are then quickly and evenly mixed with the supercritical fluid flowing out of the supercritical fluid outlet 7, and then quickly rushes to the third gauze 1. Under the action of the hydrophobic gauze, the broken droplets are broken again to form droplets with smaller particle size and more uniform distribution. In the process of supercritical fluid spraying from the outlet 7 and the mixed fluid spraying from the third gauze 1, the supercritical fluid rapidly decreases in pressure, and then the density rapidly decreases, and the mixed fluid rapidly expands. Under this phenomenon of supercritical fluid, the multiple broken droplets are again atomized in a manner similar to "explosive atomization", thereby obtaining droplets with smaller particle size and more uniform distribution, which are then used to achieve efficient and uniform cooling of the strip. The fluid flowing out of the supercritical fluid outlet 7 first enters the supercritical fluid inlet 4, then passes through the second gauze 2, and then flows out of the supercritical fluid outlet 7, wherein under the action of the second gauze 2, the supercritical fluid is realized to flow out uniformly from the supercritical fluid outlet 7 distributed along the width.

[0037] The third gauze 1 is a plain gauze, and the appropriate mesh size is selected according to the required particle size, i.e., 30 to 160 meshes. The gauze needs to be hydrophobic treated; the second gauze 2 and the first gauze 3 have 1 to 3 layers; the supercritical fluid is a substance with antioxidant effect, preferably carbon dioxide.

[0038] The present invention adopts a method combining supercritical fluid and hydrophobic gauze to realize multiple atomization of droplets, thereby obtaining a spray with small droplet size and uniform particle size distribution; at the same time, since the selected supercritical fluid is a substance with antioxidant effect, it can slow down the surface oxidation of the strip steel caused by the spray; the present invention realizes uniform distribution of water and supercritical fluid by combining narrow slits with gauze, thereby improving the uniformity of spray distribution along the width direction; the gauze not only plays the role of redistributing the fluid, but also plays a filtering role, which can effectively improve the service life of the device; by increasing the water temperature, the evaporation temperature difference of the droplets is reduced, which is conducive to the phase change of the droplets and improves the aerosol cooling heat exchange performance.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A post-plating cooling process, characterized in that: The following steps are involved: (1) Initial atomization: High-pressure water is initially atomized through the mesh; (2) Mixing: The supercritical fluid is uniformly mixed with the droplets initially atomized in step (1) through a uniform flow field of the gauze mesh; (3) Gauze atomization: The droplets mixed in step (2) are broken up again by the gauze to obtain droplets with smaller particle size and more uniform distribution; (4) Explosive atomization: In step (3), when the droplets are ejected through the gauze and then broken up again, the supercritical fluid expands to achieve "explosive atomization", obtaining droplets with smaller and more uniform particle sizes; The supercritical fluid is an antioxidant; the pressure of the high-pressure water is higher than the critical pressure of the supercritical fluid; and the temperature of the high-pressure water is higher than the critical temperature of the supercritical fluid.

2. The post-plating cooling process according to claim 1, wherein: The supercritical fluid is carbon dioxide.

3. A post-plating cooling device based on the post-plating cooling process according to claim 1 or 2, characterized in that: It includes a water channel and a supercritical fluid channel. The water channel is arranged with a water inlet, a first gauze, and a water outlet along the flow direction of high-pressure water; the supercritical fluid channel is arranged with a supercritical fluid inlet, a second gauze, and a supercritical fluid outlet along the flow direction of supercritical liquid. The water outlet and the supercritical fluid outlet merge to form a device outlet, and a third gauze is provided on the device outlet. There are two supercritical fluid channels, which are symmetrically arranged on both sides of the water channel; the third gauze is a plain gauze with a mesh count of 30 to 160, the gauze is hydrophobic treated, and the number of layers of the first gauze and the second gauze is 1 to 3.

4. The post-plating cooling device according to claim 3, characterized in that: A water flow channel is formed between the first gauze and the water outlet, and a projection of the second gauze on the water channel is located within the water flow channel.

5. The post-plating cooling device according to claim 3, characterized in that: An angle of 15° to 65° is formed between the water outlet and the supercritical liquid outlet.

6. The post-plating cooling device according to claim 3, characterized in that: The water outlet and the supercritical outlet are in the form of single-point circular holes or ellipses, and are arranged in front of the third gauze along the fluid flow direction.

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