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

Abstract

The application provides an energy-saving reconstruction method of a hot-rolling high-pressure water descaling system, comprising the following steps: S1, obtaining the actual field working condition parameters of the hot-rolling high-pressure water descaling system, including the fastest rhythm, the longest descaling overlapping time, the lowest descaling pressure and the accumulator liquid level change; S2, when the number of descaling pumps currently running in the system is at least two, one of the descaling pumps is disabled, and the descaling nozzles and descaling headers of each descaling point are designed based on the remaining running descaling pump according to the actual field working condition parameters and the maximum overlapping water volume; S3, replacing the descaling nozzles and descaling headers designed in step S2 in the hot-rolling high-pressure water descaling system; S4, running the descaling pump, obtaining the descaling pressure of the system, and comparing the descaling pressure with the lowest descaling pressure and the original system broken jet impact force respectively to determine whether the descaling requirement is met. The application can realize energy saving by reducing the use of descaling pumps.

Description

Technical Field

[0001] This invention relates to the field of high-pressure water descaling system equipment technology, and more particularly to an energy-saving renovation method for a hot rolling high-pressure water descaling system. Background Technology

[0002] There are many traditional methods for descaling slabs, such as ultrasonic descaling and water descaling. Currently, hot strip mills primarily use high-pressure water descaling. Therefore, the high-pressure water descaling system is the most critical piece of equipment on the hot strip mill production line, directly affecting the surface quality of the steel coils. If the descaling system malfunctions during production, a large amount of iron oxide scale will be pressed in, resulting in a dull steel plate surface, black spots, and discoloration, causing significant economic losses.

[0003] Currently, the descaling pump set of the high-pressure water descaling system in the hot strip roughing mill generally consists of 5 pumps, with 3 pumps operating during normal production. Figure 1 Two units are on standby, each with a 2800KW pump motor and a water supply capacity of 250m³. 3 / h, 2 x 10m 3 Gas and water tanks, 3 x 10m 3 Air tank. Due to the large opening of the descaling nozzles and their relatively high position (distance from the slab) in the original design, three descaling pumps must be used to ensure the descaling effect of the slab, resulting in high energy consumption. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an energy-saving retrofit method for a hot-rolling high-pressure water descaling system. By studying the nozzle type and arrangement at each descaling point, as well as the installation and arrangement of the descaling manifold and water-blocking manifold, this invention reduces the number of descaling pumps during operation while maintaining the basic constant impact force of the high-pressure water descaling at each point, thereby saving energy consumption and equipment maintenance costs.

[0005] The technical means employed in this invention are as follows:

[0006] An energy-saving retrofit method for a hot rolling high-pressure water descaling system includes the following steps:

[0007] S1. Obtain the actual on-site operating parameters of the hot-rolled high-pressure water descaling system, including: the fastest pace, 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 operating in the current system, one of the dephosphorization pumps shall be shut down. Based on the actual operating parameters on site and the maximum overlapping water volume, the dephosphorization nozzles and dephosphorization manifolds at each dephosphorization point shall be designed based on the remaining operating dephosphorization pumps.

[0009] S3. Replace the dephosphorization nozzle and dephosphorization manifold designed in step S2 in the hot rolling high-pressure water dephosphorization system.

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

[0011] Furthermore, when there are at least three descaling pumps in operation, after shutting down one of the descaling pumps, if the first descaling pressure obtained is greater than the minimum descaling pressure, step S2 is executed, and another descaling pump is shut down. The second descaling pressure obtained is compared with the minimum descaling pressure until it is close to or equal to the minimum descaling pressure. At the same time, the impact force of the breaking jet is close to or greater than or equal to the original impact force of the breaking jet in the system. Finally, the number of descaling pumps in operation that meet the descaling requirements is obtained.

[0012] Furthermore, the descaling points include the roughing mill descaling box, the R1 mill descaling point, and the R2 mill descaling point.

[0013] Furthermore, in step S1, the fastest pace is 40 steel pieces / hour, and the roughing mill descaling box, the R1 mill descaling point, and the R2 mill descaling point operate simultaneously.

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

[0015] Furthermore, in step S2, the design of the phosphorus removal nozzles and phosphorus removal manifolds includes at least the height of the phosphorus removal manifolds, the number of phosphorus removal nozzles, and the spacing between the phosphorus removal nozzles.

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

[0017] Furthermore, the hot rolling high-pressure water descaling system has a reverse water-blocking manifold, which is used to block water at the descaling points of the R1 and R2 mills.

[0018] The reverse water manifold includes R1 reverse water manifold and R2 reverse water manifold. The minimum descaling height, number of descaling nozzles, and spacing of descaling nozzles for R1 and R2 reverse water manifolds are designed.

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

[0020]

[0021] In the formula, f is the jet impact pressure, with units of N / mm². 2F is the actual impact force; S is the jet impact 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 impact surface; h is the vertical distance from the nozzle orifice end face to the impact force surface; α is the nozzle spray angle; τ is the spray angle in the jet thickness direction; k is the attenuation and loss coefficient caused by the nozzle's own structure.

[0022] Furthermore, the descaling pump has a motor power of 2800KW, a descaling pump pressure of 250bar, and a water supply capacity of 250m³. 3 / h.

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

[0024] This invention, through research on the nozzle type, nozzle arrangement, and installation of descaling and water-blocking manifolds at various descaling points, designs an energy-saving modification method for a high-pressure water descaling system. This method employs an energy-saving approach that increases the impact force of the high-pressure water at the descaling points, reduces water volume, and effectively utilizes accumulators to achieve the shutdown of at least one descaling pump. After replacing the manifolds and nozzles, at least one less descaling pump is required, thus achieving energy savings.

[0025] Based on the above reasons, this invention can be widely promoted in the fields of hot-rolled strip steel production machinery and equipment in the metallurgical industry. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a flowchart of the method of the present invention.

[0028] Figure 2 A schematic diagram of the basic structure of the high-pressure water descaling nozzle arrangement. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. 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.

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

[0032] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0033] Example 1

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

[0035] S1. Obtain (confirm) the actual on-site operating conditions of the hot-rolled high-pressure water descaling system, including: the fastest pace, the longest descaling overlap time, the lowest descaling pressure, and the accumulator level changes.

[0036] S2. When there are at least two descaling pumps operating in the current system, one of the descaling pumps shall be shut down. Based on the actual operating parameters on site and the maximum overlapping water volume, the descaling nozzles and descaling manifolds shall be designed based on the remaining operating descaling pumps: select descaling nozzles (with large impact force, small overlap, and small descaling water volume) and design the height of the descaling manifold.

[0037] S3. Replace the descaling nozzles and descaling manifolds designed in step S2 in the hot rolling high-pressure water descaling system; match the parameters of the descaling nozzles and descaling manifolds with the parameters after one descaling pump is shut down.

[0038] S4. Run the descaling pump to obtain the system's descaling pressure and breaking jet impact force. Compare the descaling pressure with the minimum descaling pressure and the breaking jet impact force with the system's original breaking jet impact force to determine whether the descaling requirements are met.

[0039] Preferably, when there are at least three descaling pumps in operation, after shutting down one of the descaling pumps, if the first descaling pressure obtained is greater than the minimum descaling pressure, step S2 is executed, and another descaling pump is shut down. 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 breaking jet is close to or greater than or equal to the original breaking jet impact force of the system. Finally, the number of descaling pumps in operation that meet the descaling requirements is obtained.

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

[0041]

[0042] In the formula, f is the jet impact pressure, with units of N / mm². 2 F is the actual impact force; S is the jet impact 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 impact surface; h is the vertical distance from the nozzle orifice end face to the impact force surface; α is the nozzle spray angle; τ is the spray angle in the jet thickness direction; k is the attenuation and loss coefficient caused by the nozzle's own structure.

[0043] The most significant factor affecting iron oxide removal efficiency is the crushing effect, which is the mechanical kinetic energy of the high-pressure water. The crushing effect depends on the water volume Q per unit time, water pressure p, spray arrangement, and the optimized structural parameters k of the nozzle itself. Parameters that significantly influence 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] This invention, through research on the nozzle type, nozzle arrangement, and installation of descaling and water-blocking manifolds at various descaling points, designs an energy-saving modification method for a high-pressure water descaling system. This method employs a technique that increases the impact force of the high-pressure water at the descaling points, reduces water volume, and effectively utilizes an accumulator to achieve the shutdown of one descaling pump. Figure 2Energy-saving renovation methods: After replacing the manifold and nozzles, one descaling pump is no longer needed, thus saving energy.

[0046] This invention relates to energy-saving retrofitting of three phosphorus removal pumps actually in operation on site. The method includes:

[0047] S1. Obtain the actual on-site operating conditions of the hot-rolled high-pressure water descaling system, including: the fastest pace, the longest descaling overlap time, the lowest descaling pressure, and the accumulator liquid level changes.

[0048] S2. Currently, there are three descaling pumps operating in the system. One of the descaling pumps will be shut down. Based on the actual operating parameters and the maximum overlap water volume, the descaling nozzles and descaling manifolds will be designed based on the remaining two descaling pumps: select descaling nozzles (large impact force, small overlap, and small descaling water volume) and design the height of the descaling manifold.

[0049] S3. Replace the dephosphorization nozzle and dephosphorization manifold designed in step S2 in the hot rolling high-pressure water dephosphorization system.

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

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

[0052] Descaling points include the roughing mill descaling box, the R1 mill descaling point, and the R2 mill descaling point.

[0053] The current number of descaling pump sets is 5: 3 in operation and 2 on standby.

[0054] First, one descaling pump is shut down. Then, the number of descaling pump sets in this invention is: 2 in operation, 3 on standby, for a total of 5.

[0055] Descaling pump pressure: 250 bar, flow rate: 250 m³ / h 3 / h.

[0056] The dephosphorization pump has a motor power of 2800KW and two accumulator tanks, each 10m in size. 3 .

[0057] Fastest operating speed: 40 steel bars / hour, with simultaneous operation of the roughing mill descaling box, R1 mill descaling point, and R2 mill descaling point. Simultaneous descaling time is 15 seconds (maximum descaling overlap time), minimum descaling pressure is 202 MPa, and accumulator water level drops by 300 mm.

[0058] The design of descaling nozzles and descaling manifolds should include at least the height of the descaling manifold, the number of descaling nozzles, and the spacing between the descaling nozzles. For the descaling point of the R1 mill, the minimum descaling height of the descaling manifold should be designed, and the model of the descaling nozzles should be selected.

[0059] The system has a reverse water blocking manifold, which is used to block water at the descaling points of the R1 and R2 mills. The reverse water blocking manifold includes the R1 reverse water blocking manifold and the R2 reverse water blocking manifold. The minimum descaling height, the number of descaling nozzles, and the spacing between the descaling nozzles of the R1 and R2 reverse water blocking manifolds are designed.

[0060] In this embodiment, the design results of the dephosphorization nozzles and dephosphorization manifolds at various locations are as follows:

[0061] (1) Rough rolling descaling box:

[0062]

[0063] The total water volume after the renovation was 512m³. 3 / h decreased to 403m 3 / h, water volume decreased by 27%, and the striking power decreased from 1.19 to 1.18, remaining basically unchanged.

[0064] (2) Descaling point of R1 mill

[0065]

[0066] The total water volume after the renovation was 238m³. 3 / h decreased to 192m 3 / h, water volume decreased by 24%, and striking force changed from 0.4 and 0.66 to 0.5 and 0.68, indicating an increase in striking force.

[0067] (3) Descaling point of R2 mill

[0068]

[0069]

[0070] The total water volume after the renovation was 238m³. 3 / h decreased to 192m 3 / h, water volume decreased by 24%, and the striking force changed from 0.54 and 0.64 to 0.47 and 0.65, indicating an increase in striking force.

[0071] (4) Reverse water manifold:

[0072]

[0073] Current water consumption: Descaling tank + R1 mill descaling + R2 mill descaling + water-blocking manifold: 512 + 238 + 238 + 152.7 = 1140.7 m 3 / h, the water supply capacity of the three phosphorus removal pumps is 750m³ / h. 3 / h, any shortfall will be supplied by a water tank (no more than 4m³). 3 ).

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

[0075] 4m 3 The available water tank capacity can provide 36 seconds of spraying. Considering the efficiency of the water pump and pipeline losses at 50%, the fastest three-point simultaneous descaling time is 18 seconds, which is basically consistent with the data from the field feedback.

[0076] Water volume after modification: Descaling tank + R1 mill descaling + R2 mill descaling + water-blocking manifold: 403 + 192 + 192 + 38 = 825m 3 / h, shut down 1 phosphorus removal pump, the water supply of 2 phosphorus removal pumps is 500m³ / h. 3 / h, and any shortfall is supplied by a water tank.

[0077] The fastest three-point descaling 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 current fastest rolling rhythm.

[0078] If, after shutting down one descaling pump and operating the remaining two descaling pumps, the descaling pressure meets the descaling requirements, step S2 can be executed again to shut down one descaling pump. The remaining pump will then operate, and the system descaling pressure obtained under this condition will be compared with the minimum descaling pressure. If, after operation, the descaling requirements are not met, the pump will not be satisfied. Therefore, under the operating conditions described in this application, shutting down one descaling pump and operating the remaining two achieves energy savings.

[0079] This invention redesigns the manifolds and nozzles at each descaling point, reducing the total water flow of the roughing descaling box manifold from 512m³ before the modification. 3 / h decreased to 403m after the modification 3 / h, the striking power decreased from 1.19 to 1.18, remaining basically unchanged.

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

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions 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. An energy-saving retrofit method for a hot-rolling high-pressure water descaling system, characterized in that, Includes the following steps: S1. Obtain the actual on-site operating parameters of the hot rolling high-pressure water descaling system, including: the fastest pace, the longest descaling overlap time, the lowest descaling pressure, and the accumulator liquid level change. S2. When there are at least two descaling pumps operating in the current system, one of the descaling pumps shall be shut down. Based on the actual operating parameters on site and the maximum overlapping water volume, the descaling nozzles and descaling manifolds at each descaling point shall be designed based on the remaining operating descaling pumps. S3. Replace the descaling nozzle and descaling manifold designed in step S2 in the hot rolling high-pressure water descaling system. S4. Run the descaling pump to obtain the system's descaling pressure and breaking jet impact force, and compare them with the minimum descaling pressure and the system's original breaking jet impact force to determine whether the descaling requirements are met. The descaling points include the roughing mill descaling box, the R1 mill descaling point, and the R2 mill descaling point; In step S2, the design of the descaling nozzles and descaling manifolds includes at least the height of the descaling manifolds, the number of descaling nozzles, and the spacing between the descaling nozzles. For the descaling point of the R1 mill, design the minimum descaling height of the descaling manifold and select the model of the descaling nozzle; The hot rolling high-pressure water descaling system has a reverse water-blocking manifold, which is used to block water at the descaling points of the R1 mill and the R2 mill. The reverse water blocking manifold includes R1 reverse water blocking manifold and R2 reverse water blocking manifold. The minimum descaling height, number of descaling nozzles, and spacing of descaling nozzles for R1 and R2 reverse water blocking manifolds are designed. In step S4, the impact force of the breaking jet satisfies the following formula: ； In the formula, f This refers to the jet impact pressure, expressed in N / mm². 2 ; F For actual striking power; S The area covered by the jet strike; p The water pressure in front of the nozzle; Q For pressure p The flow rate of the lower nozzle; The angle between the nozzle axis and the normal direction of the jet impact surface; h This is the vertical distance from the nozzle orifice end face to the impact surface; The nozzle's spray angle; The injection angle is in the direction of jet thickness. k This refers to the attenuation and loss coefficient caused by the nozzle's own structure.

2. The energy-saving renovation method for the hot rolling high-pressure water descaling system according to claim 1, characterized in that, When there are at least three descaling pumps in operation, after one of the descaling pumps is shut down, if the first descaling pressure obtained is greater than the minimum descaling pressure, step S2 is executed, and another descaling pump is shut down. The second descaling pressure obtained is compared with the minimum descaling pressure until it is close to or equal to the minimum descaling pressure. At the same time, the impact force of the breaking jet is close to or greater than or equal to the original impact force of the breaking jet in the system. Finally, the number of descaling pumps in operation that meet the descaling requirements is obtained.

3. The energy-saving renovation method for the hot rolling high-pressure water descaling system according to claim 1, characterized in that, In step S1, the fastest pace is 40 steel pieces / hour, and the roughing mill descaling box, the R1 mill descaling point and the R2 mill descaling point operate simultaneously. The longest descaling overlap time is 15s, the lowest descaling pressure is 202Mpa, and the accumulator water level drops by 300mm.

4. The energy-saving renovation method for the hot rolling high-pressure water descaling system according to claim 1, characterized in that, The descaling pump has a motor power of 2800KW, a pump pressure of 250bar, and a water supply capacity of 250m³. 3 / h.

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