Scrap steel preheating device and preheating method

Abstract

The present invention relates to a scrap steel preheating device and a preheating method, belonging to the technical field of iron and steel metallurgy. The scrap steel preheating device comprises a ladle with an opening at the top and a ladle cover arranged at the opening of the ladle. The ladle cover is provided with a burner that can be inserted into the ladle, and the burner is connected with a fuel pipeline, an oxygen pipeline and an air pipeline, so that the burner can use air and / or oxygen for combustion. The ladle cover is also provided with a smoke exhaust pipeline, and the smoke exhaust pipeline is provided with a smoke temperature detection device. When the scrap steel is preheated, the scrap steel to be preheated is added to the ladle in multiple times, and after each addition of the scrap steel, the scrap steel is preheated to a set temperature through the burner. The present invention realizes dual combustion of the burner by connecting the burner with the fuel pipeline, the oxygen pipeline and the air pipeline; by adopting different heating methods in different heating stages, not only the fuel is saved to the maximum extent, but also the heating speed is improved, and the cost of scrap steel preheating is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of iron and steel metallurgy, and relates to a scrap steel preheating device and a preheating method. Background Art

[0002] my country is a major steel producer, and its steel output has ranked first in the world for many years. In recent years, with the continuous increase in steel supply, the release of scrap steel has also continued to increase, and the proportion of scrap steel used in domestic steelmaking has also continued to increase. Data shows that in 2019, the proportion of scrap steel will exceed 20%.

[0003] Compared with the traditional long converter process, the short process of electric furnace steelmaking has advantages in investment, energy saving, and environmental protection. Therefore, with the continuous increase in my country's scrap steel reserves, electric furnace steelmaking will inevitably be the development trend of the industry in the future.

[0004] Electric furnaces are divided into medium frequency furnaces, arc furnaces, resistance furnaces, etc. They use electromagnetic, electric arc, conductor impedance and other methods to heat and melt scrap steel. Therefore, the main production cost of electric furnace steelmaking is electricity consumption, and the electricity consumption per ton of steel reaches 400-600kw.h.

[0005] In addition, the scrap steel needs to be heated from room temperature to melting temperature, which takes a long time. Due to the limited conversion efficiency of primary energy into electrical energy, the comprehensive thermal efficiency of the electric furnace is not high. At the same time, steel production is also limited by the heating rate.

[0006] Scrap steel preheating is a method that can solve the above problems, but the current scrap steel preheating has the problems of high energy consumption, uneven preheating, low preheating temperature and slow rate. Summary of the invention

[0007] In view of this, the purpose of the present application is to provide a scrap steel preheating device and a preheating method to solve the problem of high energy consumption in scrap steel preheating.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] A scrap steel preheating device comprises a ladle with an opening at the top and a ladle cover arranged at the ladle opening, the ladle cover is provided with a burner which can be extended into the ladle, the burner is connected with a fuel pipeline, an oxygen pipeline and an air pipeline so that the burner can use air and / or oxygen to assist combustion; the ladle cover is also provided with a smoke exhaust pipeline, and the smoke exhaust pipeline is provided with a smoke temperature detection device.

[0010] Optionally, a ladle cover bracket is further included, which includes a fixing member located at one side of the ladle and a connecting rod rotatably connected to the fixing member, and the other end of the connecting rod is fixedly connected to the ladle cover.

[0011] Optionally, the burner is located at the center of the ladle cover.

[0012] Optionally, the ladle cover is provided with a plurality of burners, which are evenly distributed on concentric circles concentric with the ladle cover.

[0013] Optionally, the burner is eccentrically arranged relative to the ladle cover, and the ladle cover is provided with a rotating device which can rotate around its axis, and the burner is arranged on the rotating device.

[0014] Optionally, the rotating device includes a rotating member and a motor arranged on the ladle cover, the upper part of the rotating member is provided with a driven wheel concentric with the rotating member, the output shaft of the motor is provided with a driving wheel meshing with the driven wheel, the burner is arranged on the rotating member, the lower part of the rotating member has a connecting portion matching the annular hole arranged on the ladle cover, and the burner follows the rotating member and rotates around the axis of the ladle cover under the drive of the motor.

[0015] Optionally, a ladle bracket is also included, which includes a base located at the bottom of the ladle, limit members relatively arranged on both sides of the ladle, and casters arranged on the base, and the limit members are fixedly connected to the base.

[0016] A scrap steel preheating method uses the scrap steel preheating device described above to add the scrap steel to be preheated into a ladle in multiple times, and after each addition of the scrap steel, the scrap steel is preheated to a set temperature through a burner.

[0017] Optionally, when the exhaust gas temperature is less than or equal to T1, the burner uses air to assist combustion; when the exhaust gas temperature is greater than T1, the burner uses oxygen-enriched or pure oxygen to assist combustion.

[0018] Optionally, T1 is 500°C to 700°C.

[0019] The beneficial effects of the present invention are:

[0020] 1. The present invention realizes dual combustion-supporting of the burner by connecting the burner with the fuel pipeline, the oxygen pipeline and the air pipeline. By adopting different heating methods in different heating stages, it not only saves fuel to the maximum extent, but also improves the heating speed and reduces the preheating cost of scrap steel.

[0021] 2. The present invention realizes layered preheating by adding scrap steel multiple times, thereby improving the temperature uniformity of scrap steel preheating.

[0022] 3. The present invention not only improves the preheating uniformity of the scrap steel, but also improves the preheating speed of the scrap steel by arranging multiple burners on the ladle cover.

[0023] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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 in conjunction with the accompanying drawings, wherein:

[0025] Figure 1 It is a schematic structural diagram of the scrap steel preheating device of the present invention.

[0026] Figure numerals: base 1, caster 11, limit piece 12, ladle 2, lifting ear 21, ladle cover 3, burner 31, fuel pipeline 32, oxygen pipeline 33, air pipeline 34, smoke exhaust pipeline 35, smoke temperature detection device 36, ladle cover bracket 37, scrap steel 4. DETAILED DESCRIPTION

[0027] The following describes the embodiments of the present invention by 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 only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0028] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0029] 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 the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position 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.

[0030] See also Figure 1 A scrap steel preheating device comprises a ladle 2 with an opening at the top and a ladle cover 3 arranged at the ladle opening. The ladle cover 3 is provided with a burner 31 which can be inserted into the ladle 2. The burner 31 is connected with a fuel pipeline 32, an oxygen pipeline 33 and an air pipeline 34 so that the burner 31 can use air and / or oxygen to assist combustion. The ladle cover 3 is also provided with a smoke exhaust pipeline 35, and the smoke exhaust pipeline 35 is provided with a smoke temperature detection device 36.

[0031] In order to facilitate opening of the ladle cover 3, the present invention is also provided with a ladle cover bracket 37, which includes a fixing part located on one side of the ladle 2 and a connecting rod rotatably connected to the fixing part, the other end of the connecting rod is fixedly connected to the ladle cover 3, the fixing part can be directly fixed on the ground, and a baffle for limiting the rotation angle of the ladle cover 3 is also provided on the fixing part.

[0032] Preferably, the burner 31 is located at the center of the ladle cover 3 .

[0033] In order to improve the uniformity of scrap preheating, the burner 31 of the present invention is eccentrically arranged relative to the ladle cover 3, and the burner 31 is arranged to be rotatable around the axis of the ladle cover 3. The specific arrangement is as follows: a rotating device is arranged on the ladle cover 3, and an annular hole concentric with the ladle cover 3 is opened at a position of the ladle cover 3 relative to the burner, the rotating device includes an annular rotating member and a motor fixed on the ladle cover 3, the upper part of the rotating member is provided with a driven wheel concentric with the ladle cover, and the output shaft of the motor is provided with a driving wheel meshing with the driven wheel; the burner 31 is arranged on the rotating member, and the lower part of the rotating member has a connecting portion matching the annular hole, the connecting portion is located in the annular hole, and the burner 31 follows the rotating member and rotates around the axis of the ladle cover 3 under the drive of the motor.

[0034] The present invention can also improve the preheating uniformity by arranging a plurality of burners 31 on the ladle cover 3, preferably the burners 31 are evenly distributed on concentric circles concentric with the ladle cover 3. This arrangement can not only improve the preheating uniformity of the scrap steel, but also increase the preheating speed of the scrap steel.

[0035] Preferably, a ladle support is also included, which includes a base 1 located at the bottom of the ladle, limit members 12 relatively arranged on both sides of the ladle, and casters 11 arranged on the base 1, and the limit members 12 are fixedly connected to the base 1.

[0036] A scrap steel preheating method uses the scrap steel preheating device to add the scrap steel 4 to be preheated into the ladle 2 in multiple times, and after each addition of the scrap steel 4, the scrap steel is preheated to a set temperature through a burner 31.

[0037] In order to reduce heating costs, when the exhaust gas temperature is less than or equal to T1, the burner 31 uses air to assist combustion; when the exhaust gas temperature is greater than T1, the burner 31 uses oxygen-enriched or pure oxygen to assist combustion.

[0038] Preferably, T1 is 500°C to 700°C.

[0039] Example 1

[0040] A scrap steel preheating device comprises a base 1, a ladle 2 and a ladle cover 3. The ladle 2 is used to place scrap steel 4. The base 1 is used to support the ladle 2. A limiting member 12 is arranged on the base 1. The ladle cover 3 is arranged above the ladle 2. A burner 31 is arranged on the ladle cover 3. The burner 31 is air / oxygen-enriched dual combustion-supporting. A smoke exhaust pipe 35 is also arranged on the ladle cover 3. A smoke temperature detection device 36 for detecting the exhaust temperature is arranged on the smoke exhaust pipe 35. The smoke temperature detection device 36 is a temperature sensor.

[0041] Specifically:

[0042] In this embodiment, a limiter 12 and a movable caster 11 are arranged on the base 1 of the scrap steel preheating device. One end of the limiter 12 is connected to the base 1, and the other end is used to limit the horizontal movement of the ladle 2 on the base 1; the caster 11 is arranged below the base 1 to facilitate the movement of the base 1 and the ladle 2.

[0043] In this embodiment, the ladle 2 of the scrap steel preheating device is placed on the base 1, so that the ladle 2 is located in the limit piece 12 on the base 1 and cannot move horizontally alone. The inner cavity of the ladle 2 is used to place the scrap steel 4, and the ladle 2 is provided with a lifting lug 21 for lifting and flipping the ladle 2.

[0044] The ladle cover 3 of the scrap steel preheating device of this embodiment is located above the ladle 2. The ladle cover 3 is provided with a burner 31 for preheating the scrap steel 4. One or more burners 31 may be provided. The outlet of the burner 31 faces the inner cavity of the ladle 2. The burner 31 is connected to a fuel pipeline 32, an oxygen pipeline 33 and an air pipeline 34. The burner 31 adopts an air / oxygen dual combustion-supporting mode. The ladle cover 3 is also provided with a smoke exhaust pipeline 35, and a temperature detection device 36 is provided on the smoke exhaust pipeline 35. The ladle cover 3 is connected to a ladle cover bracket 37. One end of the ladle cover bracket 37 is connected to the ladle cover 3, and the other end is fixed on the ground. The ladle cover bracket 37 enables the ladle cover 3 to be opened or closed relative to the ladle 2.

[0045] Example 2

[0046] A method for preheating scrap steel comprises the following steps: placing an empty ladle 2 in a stopper 12 on a base 1, adding scrap steel 4 into the ladle 2 in multiple times; each time the scrap steel 4 is added, the ladle cover 3 is covered, the burner 31 is opened, and the smoke temperature detection device 36 located on the smoke exhaust pipe 35 is used to detect the smoke temperature. When the smoke temperature is less than or equal to T1, the burner 31 adopts an air-assisted combustion mode, that is, the burner 31 is fed with fuel gas and air through a fuel pipe 32 and an air pipe 34. When the smoke temperature is greater than T1, the burner 31 adopts an oxygen-enriched or pure oxygen-assisted combustion mode, that is, the burner 31 is fed with fuel gas and air through a fuel pipe 32 and an air pipe 34. 2. Fuel, oxygen and air are introduced through the oxygen pipeline 33 and the air pipeline 34 to realize oxygen-enriched combustion, or fuel and oxygen are introduced through the fuel pipeline 32 and the oxygen pipeline 33 to realize pure oxygen combustion, and T1 is 600°C; when the flue gas temperature is greater than T2, the burner 31 is closed, and the ladle cover 3 is opened to continue adding scrap steel 4, and T2 is the flue gas temperature when the scrap steel 4 reaches the process preheating temperature; the above heating process is repeated until the scrap steel 4 in the ladle 2 is full and the exhaust gas temperature is greater than T2, the burner 31 is closed, the scrap steel preheating process is completed, and then the ladle 2 is moved to the next process through the base 1.

[0047] The present invention adds the scrap steel 4 into the ladle 2 for multiple times. After each addition of the scrap steel, the burner 31 located on the ladle cover 3 is opened to preheat the scrap steel 4. During the preheating process, when the exhaust gas temperature is lower than a certain value, the burner 31 uses air to assist combustion. When the exhaust gas temperature is higher than a certain value, the burner 31 uses oxygen-enriched or pure oxygen to assist combustion. When the exhaust gas temperature exceeds a certain value of the preheating temperature required for the scrap steel, the burner 31 is closed.

[0048] The present invention can save fuel to the maximum extent and realize rapid heating by using different heating methods at different temperatures; and realizes layered preheating by adding scrap steel multiple times, thereby improving the temperature uniformity of scrap steel preheating.

[0049] The present invention is used for preheating scrap steel before it enters an electric furnace in a short process of steel production, which greatly reduces the power consumption of subsequent electric furnace processes, reduces emissions, reduces production costs, and improves the competitiveness of the enterprise. It solves the current problems of high energy consumption of electric furnaces, large energy consumption for scrap steel preheating, uneven preheating and slow heating rate, saves energy, reduces costs, and reduces pollutant emissions.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. 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 solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for preheating scrap steel, characterized in that: A scrap steel preheating device is used to preheat scrap steel, the scrap steel preheating device comprises a ladle with an opening at the top and a ladle cover arranged at the opening of the ladle, as well as a ladle cover bracket and a ladle bracket, the ladle cover is provided with a burner which can be inserted into the ladle, the burner is connected with a fuel pipeline, an oxygen pipeline and an air pipeline, so that the burner can use air and / or oxygen for combustion; the ladle cover is also provided with a smoke exhaust pipeline, and the smoke exhaust pipeline is provided with a smoke temperature detection device; the ladle cover bracket comprises a fixing part located on one side of the ladle and a connecting rod with one end rotatably connected to the fixing part, and the other end of the connecting rod is fixedly connected to the ladle cover; the burner is eccentrically arranged relative to the ladle cover , a rotating device that can rotate around its axis is provided on the ladle cover, and the burner is arranged on the rotating device; the rotating device includes a rotating member and a motor arranged on the ladle cover, the upper part of the rotating member is provided with a driven wheel concentric with the rotating member, the output shaft of the motor is provided with a driving wheel meshing with the driven wheel, the burner is arranged on the rotating member, the lower part of the rotating member has a connecting part matching the annular hole arranged on the ladle cover, and the burner follows the rotating member and rotates around the axis of the ladle cover under the drive of the motor; the ladle bracket includes a base located at the bottom of the ladle and limit members arranged on both sides of the ladle relatively, and casters arranged on the base, and the limit members are fixedly connected to the base; The scrap steel to be preheated is added into the ladle in several times, and the scrap steel in the ladle is preheated to the set temperature after each addition; when the exhaust gas temperature is less than or equal to T1, the burner adopts air to assist combustion; when the exhaust gas temperature is greater than T1, the burner adopts oxygen-enriched or pure oxygen to assist combustion, and T1 is 600℃.

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