Energy-saving transformation method of hot rolling high-pressure water descaling system

Abstract

The invention provides an energy-saving transformation method for a hot-rolling high-pressure water descaling system, which comprises the following steps: S1, acquiring field actual working condition parameters of the hot-rolling high-pressure water descaling system, including fastest rhythm, longest descaling overlapping time, minimum descaling pressure and liquid level change of an energy accumulator; s2, when the number of the dephosphorization pumps running in the current system is at least two, one dephosphorization pump is stopped, and dephosphorization nozzles and dephosphorization headers at all dephosphorization point positions are designed based on the remaining running dephosphorization pumps according to the actual working condition parameters on site and the maximum overlapped water amount; s3, the dephosphorization nozzle and the dephosphorization header designed in the step S2 are replaced in a hot rolling high-pressure water dephosphorization system; and S4, the dephosphorization pump is operated, the descaling pressure of the system is obtained and compared with the minimum descaling pressure and the original breaking jet impact force of the system, and whether the dephosphorization requirement is met or not is judged. According to the invention, energy saving can be realized by reducing the use of the descaling pump.

Description

Technical Field

[0001] The invention relates to the technical field of high-pressure water descaling system equipment, and in particular to an energy-saving transformation method for a hot rolling high-pressure water descaling system. Background Art

[0002] There are many traditional slab descaling methods, such as ultrasonic descaling, water descaling, etc. The current descaling methods for hot rolling are mainly concentrated on high-pressure water descaling. Therefore, the high-pressure water descaling system is the most core equipment affecting the surface quality of steel coils on the hot rolling production line. Its stable operation is directly related to the surface quality of steel coils. If the descaling system is abnormal during production, a large amount of iron oxide will be pressed in, and the surface of the steel plate will be dull, black spots, color spots, etc. will appear, which will also cause huge economic losses.

[0003] At present, the descaling pump group of the hot rolling rough rolling high-pressure water descaling system generally has 5 pumps, and 3 pumps work during normal production ( Figure 1 ), 2 spare pumps, each pump motor 2800KW, water supply 250m 3 / h, 2 10m 3 Gas and water tanks, 3 pcs 10m 3 Gas tank. Due to the large opening of the descaling nozzle in the original design and the high position (distance from the slab), in order to ensure the descaling effect of the slab, three descaling pumps must be used, which consumes a lot of energy. Summary of the invention

[0004] According to the technical problems raised above, a method for energy-saving transformation of a hot rolling high-pressure water descaling system is provided. The invention reduces one descaling pump during operation, saves energy consumption and equipment maintenance costs, by studying the nozzle model and nozzle arrangement of each descaling point and the installation arrangement of the descaling manifold and the water retaining manifold, while ensuring that the impact force of the high-pressure water descaling at each point remains basically unchanged.

[0005] The technical means adopted by the present invention are as follows:

[0006] A method for energy-saving transformation of a hot rolling high-pressure water descaling system comprises the following steps:

[0007] S1. Obtain the actual working parameters of the hot rolling high-pressure water dephosphorization system, including the fastest rhythm, the longest descaling overlap time, the lowest descaling pressure and the accumulator liquid level change;

[0008] S2. When there are at least two dephosphorization pumps in operation in the current system, one of the dephosphorization pumps is stopped, and the dephosphorization nozzles and dephosphorization headers at each dephosphorization point are designed based on the remaining dephosphorization pumps according to the actual operating parameters on site and the maximum overlap water volume;

[0009] S3, replacing the dephosphorization nozzle and dephosphorization header designed in step S2 in the hot rolling high-pressure water dephosphorization system;

[0010] S4. Run the dephosphorization pump to obtain the system's descaling pressure and crushing jet impact force, and compare them with the minimum descaling pressure and the system's original crushing jet impact force to determine whether the dephosphorization requirements are met.

[0011] Furthermore, when the number of phosphorus removal pumps in operation is at least three, after deactivating one of the phosphorus removal pumps, when the first phosphorus removal pressure obtained is greater than the minimum descaling pressure, execute step S2, and continue to deactivate one phosphorus removal pump, and compare the obtained second descaling pressure with the minimum descaling pressure until it is close to or equal to the minimum descaling pressure, and at the same time, the impact force of the broken jet is close to or greater than or equal to the original broken jet impact force of the system, and finally the number of running phosphorus removal pumps that meets the phosphorus removal requirements is obtained.

[0012] Furthermore, the dephosphorization points include a rough rolling descaling box, an R1 rolling mill descaling point and an R2 rolling mill descaling point.

[0013] Further, in the step S1, the fastest rhythm is 40 steel pieces / hour, and the rough rolling descaling box, the R1 rolling mill descaling point and the R2 rolling mill descaling point are operated simultaneously;

[0014] The longest descaling overlap time is 15s, the minimum descaling pressure is 202Mpa, and the accumulator water level drops by 300mm.

[0015] Furthermore, in step S2, the design of the dephosphorization nozzles and the dephosphorization header at least includes: the height of the dephosphorization header, the number of the dephosphorization nozzles, and the spacing between the dephosphorization nozzles.

[0016] Furthermore, for the descaling point of the R1 rolling mill, the minimum descaling height of the dephosphorization header is designed, and the model of the dephosphorization nozzle is selected.

[0017] Furthermore, the hot rolling high-pressure water dephosphorization system has a water-blocking manifold for blocking water at the descaling points of the R1 rolling mill and the R2 rolling mill;

[0018] The anti-water retaining header includes an R1 anti-water retaining header and an R2 anti-water retaining header, and the minimum descaling height, the number of dephosphorization nozzles, and the spacing between the dephosphorization nozzles of the R1 anti-water retaining header and the R2 anti-water retaining header are designed.

[0019] Furthermore, in step S4, the impact force of the crushing jet satisfies the following formula:

[0020]

[0021] Where f is the jet impact pressure, in N / mm 2; F is the actual striking force; S is the jet striking coverage area; p is the water pressure in front of the nozzle; Q is the flow rate of the nozzle under pressure p; β is the angle between the nozzle axis and the normal direction of the jet striking surface; h is the vertical distance from the nozzle nozzle end face to the striking force surface; α is the nozzle injection angle; τ is the injection angle in the jet thickness direction; k is the attenuation and loss coefficient caused by the nozzle structure itself.

[0022] Furthermore, the motor power of the dephosphorization pump is 2800KW, the descaling pump pressure is 250bar, and the water supply of the dephosphorization pump is 250m 3 / h.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] The present invention designs a high-pressure water descaling system energy-saving transformation method by studying the nozzle model, nozzle arrangement, descaling header and water retaining header installation of each descaling point, and adopts an energy-saving transformation method that stops at least one descaling pump by increasing the impact force of the high-pressure water descaling point, reducing the water volume, and making good use of the accumulator. After replacing the header and nozzle, at least one descaling pump is reduced from use, which can achieve energy saving.

[0025] Based on the above reasons, the present invention can be widely promoted in the fields of hot-rolled strip production machinery and equipment in the metallurgical industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0027] Figure 1 Flow chart of the method of the present invention.

[0028] Figure 2 Schematic diagram of the basic structure of the high-pressure water descaling nozzle arrangement. DETAILED DESCRIPTION

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0032] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. Meanwhile, it should be clear that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0033] Example 1

[0034] The present invention provides an energy-saving transformation method for a hot rolling high-pressure water descaling system, comprising the following steps:

[0035] S1. Obtain (implement) the actual on-site working conditions of the hot rolling high-pressure water dephosphorization system, including: the fastest rhythm, the longest descaling overlap time, the lowest descaling pressure and the accumulator liquid level change;

[0036] S2. When there are at least two dephosphorization pumps in operation in the current system, one of the dephosphorization pumps is stopped, and the dephosphorization nozzle and dephosphorization header are designed based on the actual working parameters on site and the maximum overlap water volume and the remaining dephosphorization pumps: a descaling nozzle (with large impact force, small overlap, and small descaling water volume) is selected, and the height of the descaling header is designed;

[0037] S3, replacing the dephosphorization nozzle and dephosphorization header designed in step S2 in the hot rolling high-pressure water dephosphorization system; the parameters of the descaling nozzle and the descaling header are matched with the parameters after one descaling pump is deactivated;

[0038] S4. Run the dephosphorization pump to obtain the descaling pressure and the impact force of the broken jet of the system, compare the dephosphorization pressure with the minimum descaling pressure, and compare the impact force of the broken jet with the original impact force of the broken jet of the system to determine whether the dephosphorization requirements are met.

[0039] Preferably, when the number of phosphorus removal pumps in operation is at least three, after deactivating one of the phosphorus removal pumps, when the first phosphorus removal pressure obtained is greater than the minimum descaling pressure, step S2 is executed, and another phosphorus removal pump is deactivated, and the second descaling pressure obtained is compared with the minimum descaling pressure until it is close to or equal to the minimum descaling pressure (the descaling pressure is greater than or equal to the minimum descaling pressure). At the same time, the impact force of the broken jet is close to or greater than or equal to the original broken jet impact force of the system, and finally the number of running phosphorus removal pumps that meets the phosphorus removal requirements is obtained.

[0040] Preferably, in step S4, the impact force of the crushing jet satisfies the following formula:

[0041]

[0042] Where f is the jet impact pressure, in N / mm 2 ; F is the actual striking force; S is the jet striking coverage area; p is the water pressure in front of the nozzle; Q is the flow rate of the nozzle under pressure p; β is the angle between the nozzle axis and the normal direction of the jet striking surface; h is the vertical distance from the nozzle nozzle end face to the striking force surface; α is the nozzle injection angle; τ is the injection angle in the jet thickness direction; k is the attenuation and loss coefficient caused by the nozzle structure itself.

[0043] The biggest influence on the iron oxide removal effect is the crushing effect, that is, the mechanical kinetic energy of high-pressure water. The crushing effect depends on the amount of water sprayed per unit time Q, water pressure p, spray arrangement, and the structural optimization parameter k of the nozzle itself. The parameters that have a greater impact on the jet impact force are the vertical distance h from the nozzle orifice to the slab surface and the attenuation coefficient k caused by the nozzle's own structure.

[0044] Example 2

[0045] The present invention designs a method for energy-saving transformation of high-pressure water descaling system by studying the nozzle model, nozzle arrangement and installation of descaling manifold and water retaining manifold at each descaling point. The method adopts a method to improve the impact force of high-pressure water descaling point, reduce the water volume and make good use of the accumulator to achieve the purpose of stopping one descaling pump ( Figure 2) energy-saving transformation method. After replacing the header and nozzle, one descaling pump is reduced to use, achieving energy saving.

[0046] The present invention aims at three dephosphorization pumps actually operating on site, and performs energy-saving transformation, and the method includes:

[0047] S1. Obtain the actual working conditions of the hot rolling high-pressure water dephosphorization system, including the fastest rhythm, the longest descaling overlap time, the lowest descaling pressure and the accumulator liquid level change;

[0048] S2. There are three dephosphorization pumps running in the current system. One of the dephosphorization pumps is stopped. Based on the actual working parameters on site and the maximum overlapping water volume, the dephosphorization nozzle and dephosphorization header are designed based on the remaining two dephosphorization pumps: a descaling nozzle (with large impact force, small overlapping volume, and small descaling water volume) is selected, and the height of the descaling header is designed;

[0049] S3, replacing the dephosphorization nozzle and dephosphorization header designed in step S2 in the hot rolling high-pressure water dephosphorization system;

[0050] S4. Run two dephosphorization pumps to obtain the descaling pressure of the system, compare the dephosphorization pressure with the minimum descaling pressure, and determine whether the dephosphorization requirements are met.

[0051] Specifically, in this embodiment, the equipment parameters of the hot rolling high-pressure water dephosphorization system are:

[0052] The dephosphorization points include the rough rolling descaling box, the R1 rolling mill descaling point and the R2 rolling mill descaling point.

[0053] The current number of descaling pump sets: 3 in operation, 2 in standby, a total of 5.

[0054] First, one dephosphorization pump is stopped, and then the number of the descaling pump group of the present invention is: 2 in operation and 3 in standby, for a total of 5.

[0055] Descaling pump pressure: 250 bar, flow rate: 250 m 3 / h.

[0056] Motor power of dephosphorization pump: 2800KW, energy storage tank: 2, 10m 3 .

[0057] The fastest pace: 40 steel pieces / hour, the roughing descaling box, R1 mill descaling point and R2 mill descaling point are running at the same time. The descaling time is 15s (the longest descaling overlap time), the minimum descaling pressure is 202Mpa, and the accumulator water level drops by 300mm.

[0058] The design of dephosphorization nozzles and dephosphorization headers at least includes: the height of the dephosphorization header, the number of dephosphorization nozzles and the spacing between the dephosphorization nozzles. For the descaling point of the R1 rolling mill, the minimum descaling height of the dephosphorization header is designed, and the model of the dephosphorization nozzle is selected.

[0059] The system has a water-blocking header, which is used to block water at the descaling points of the R1 rolling mill and the R2 rolling mill; the water-blocking header includes the R1 water-blocking header and the R2 water-blocking header, and the minimum descaling height, the number of dephosphorization nozzles, and the spacing between the dephosphorization nozzles of the R1 water-blocking header and the R2 water-blocking header are designed.

[0060] In this embodiment, the design results of the dephosphorization nozzles and dephosphorization headers are as follows:

[0061] (1) Rough rolling descaling box:

[0062]

[0063] After the transformation, the total water volume increased from 512m 3 / h reduced to 403m 3 / h, the water volume decreased by 27%, and the impact force dropped from 1.19 to 1.18, which remained basically unchanged.

[0064] (2) R1 mill descaling point

[0065]

[0066] After the transformation, the total water volume increased from 238m 3 / h reduced to 192m 3 / h, the water volume decreased by 24%, the impact force changed from 0.4, 0.66 to 0.5, 0.68, and the impact force increased.

[0067] (3) R2 mill descaling point

[0068]

[0069]

[0070] After the transformation, the total water volume increased from 238m 3 / h reduced to 192m 3 / h, the water volume decreased by 24%, the impact force changed from 0.54, 0.64 to 0.47, 0.65, and the impact force increased.

[0071] (4) Water blocking header:

[0072]

[0073] Current water consumption: descaling box + R1 mill descaling + R2 mill descaling + water retaining header: 512 + 238 + 238 + 152.7 = 1140.7m 3 / h, the water supply of 3 dephosphorization pumps is 750m 3 / h, the shortfall is provided by water tanks (no more than 4m 3 ).

[0074] 1140.7-750=390.7m 3 / h=0.109m 3 / s.

[0075] 4m 3 The available water tank can provide a total of 36 seconds of spraying. Taking into account the efficiency of the water pump and the loss of the pipeline at 50%, the fastest descaling time for three points at the same time is 18 seconds, which is basically consistent with the data fed back from the site.

[0076] Water volume after transformation: descaling box + R1 mill descaling + R2 mill descaling + water retaining header: 403 + 192 + 192 + 38 = 825m 3 / h, stop one dephosphorization pump, and the water supply of the two dephosphorization pumps is 500m 3 / h, the shortfall is provided by the water tank.

[0077] The fastest descaling time at three points at the same time is 22 seconds. It can be clearly seen that the amount of water required to replenish the water tank after stopping one pump is lower, which can meet the existing fastest rolling rhythm.

[0078] When one dephosphorization pump is stopped and the remaining two dephosphorization pumps are operated, and the dephosphorization pressure meets the dephosphorization requirement, step S2 can be performed again, and one dephosphorization pump is continued to be stopped, and the remaining one dephosphorization pump is operated, and the system descaling pressure obtained after operation in this case is compared with the minimum descaling pressure. After operation, it does not meet the dephosphorization requirement. In this application, one dephosphorization pump is stopped and the remaining two dephosphorization pumps are operated, which can achieve energy saving.

[0079] The present invention redesigns the headers and nozzles of each descaling point, and the total water volume of the header of the rough rolling descaling box is increased from 512m 3 / h is reduced to 403m / h after transformation 3 / h, the striking force dropped from 1.19 to 1.18, basically unchanged.

[0080] The present invention has been put into use in the rough rolling descaling system of a 2050mm hot rolling line in a certain factory. After long-term actual operation and use, the technical effect of energy saving has been fully achieved.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for energy-saving transformation of a hot rolling high-pressure water descaling system, characterized in that: The steps include: S1. Obtain the actual working parameters of the hot rolling high-pressure water dephosphorization system, including the fastest rhythm, the longest descaling overlap time, the lowest descaling pressure and the accumulator liquid level change; S2. When there are at least two dephosphorization pumps in operation in the current system, one of the dephosphorization pumps is stopped, and the dephosphorization nozzles and dephosphorization headers at each dephosphorization point are designed based on the remaining dephosphorization pumps according to the actual operating parameters on site and the maximum overlap water volume; S3, replacing the dephosphorization nozzle and dephosphorization header designed in step S2 in the hot rolling high-pressure water dephosphorization system; S4. Run the dephosphorization pump to obtain the system's descaling pressure and crushing jet impact force, and compare them with the minimum descaling pressure and the system's original crushing jet impact force to determine whether the dephosphorization requirements are met.

2. The energy-saving transformation method of the hot rolling high-pressure water descaling system according to claim 1 is characterized in that: When there are at least three phosphorus removal pumps in operation, after deactivating one of the phosphorus removal pumps, when the first phosphorus removal pressure obtained is greater than the minimum descaling pressure, execute step S2, and continue to deactivate one phosphorus removal pump, and compare the obtained second descaling pressure with the minimum descaling pressure until it is close to or equal to the minimum descaling pressure, and at the same time, the crushing jet impact force is close to or greater than or equal to the original crushing jet impact force of the system, and finally the number of phosphorus removal pumps in operation that meets the phosphorus removal requirements is obtained.

3. The energy-saving transformation method of the hot rolling high-pressure water descaling system according to claim 1 is characterized in that: The dephosphorization points include a rough rolling descaling box, an R1 rolling mill descaling point and an R2 rolling mill descaling point.

4. The energy-saving transformation method of the hot rolling high-pressure water descaling system according to claim 3 is characterized in that: In the step S1, the fastest rhythm is 40 steel pieces / hour, and the rough rolling descaling box, the R1 rolling mill descaling point and the R2 rolling mill descaling point are operated simultaneously; The longest descaling overlap time is 15s, the minimum descaling pressure is 202Mpa, and the accumulator water level drops by 300mm.

5. The energy-saving transformation method of the hot rolling high-pressure water descaling system according to claim 3 is characterized in that: In the step S2, the design of the dephosphorization nozzles and the dephosphorization header at least includes: the height of the dephosphorization header, the number of the dephosphorization nozzles and the spacing between the dephosphorization nozzles.

6. The energy-saving transformation method of the hot rolling high-pressure water descaling system according to claim 5 is characterized in that: For the descaling point of the R1 rolling mill, the minimum descaling height of the dephosphorization header is designed, and the model of the dephosphorization nozzle is selected.

7. The energy-saving transformation method of the hot rolling high-pressure water descaling system according to claim 5 is characterized in that: The hot rolling high-pressure water dephosphorization system has a water-blocking header for blocking water at the descaling points of the R1 rolling mill and the R2 rolling mill; The anti-water retaining header includes an R1 anti-water retaining header and an R2 anti-water retaining header, and the minimum descaling height, the number of dephosphorization nozzles, and the spacing between the dephosphorization nozzles of the R1 anti-water retaining header and the R2 anti-water retaining header are designed.

8. The energy-saving transformation method of the hot rolling high-pressure water descaling system according to claim 5 is characterized in that: In step S4, the impact force of the crushing jet satisfies the following formula: Where f is the jet impact pressure, in N / mm 2 ; F is the actual striking force; S is the jet striking coverage area; p is the water pressure in front of the nozzle; Q is the flow rate of the nozzle under pressure p; β is the angle between the nozzle axis and the normal direction of the jet striking surface; h is the vertical distance from the nozzle nozzle end face to the striking force surface; α is the nozzle injection angle; τ is the injection angle in the jet thickness direction; k is the attenuation and loss coefficient caused by the nozzle's own structure.

9. The energy-saving transformation method of the hot rolling high-pressure water descaling system according to claim 1 is characterized in that: The motor power of the dephosphorization pump is 2800KW, the descaling pump pressure is 250bar, and the water supply of the dephosphorization pump is 250m 3 / h.

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