Blowing device for reducing gas of low-carbon blast furnace

Abstract

The invention relates to the technical field of blast furnace metallurgy, and discloses a low-carbon blast furnace reducing gas injection device which comprises a tuyere copper bush, the tuyere copper bush is internally provided with an axially-extending hot air channel, an air outlet end of the tuyere copper bush is arranged at one end of the hot air channel, and the other end of the hot air channel is connected with a hot air bustle pipe through a pipeline; the gas channel and the pulverized coal channel respectively form an included angle of 5-20 degrees with the axial direction of the hot air channel, and the injection direction is the same as the flow direction of the hot air; the axial distance between the gas channel and the end of the tuyere and the axial distance between the pulverized coal channel and the end of the tuyere are 70-160 mm. By adopting the injection device, the highest temperature of combustion can be increased, the space of a tuyere rotation area is improved, and the injection device has important significance on production of a blast furnace.

Description

Technical Field

[0001] The present invention relates to the technical field of blast furnace ironmaking, and in particular to a low-carbon blast furnace reducing gas injection device. Background Art

[0002] Hydrogen-rich smelting and top gas circulation technologies are currently considered the main ways to achieve the "dual carbon" goals in steel production. Blast furnace hydrogen-rich smelting primarily involves injecting hydrogen-rich gases, such as natural gas, coke oven gas, coal-to-gas, and hydrogen, into the furnace through tuyere. Combustion at the front of the tuyere provides heat and reducing agents for blast furnace smelting. It also improves the reduction process of blast furnace charges, promotes indirect reduction, and reduces the degree of direct reduction, thereby reducing blast furnace fuel consumption. Top gas circulation decarbonizes the blast furnace top gas and then injects the remaining highly reducing gas into the blast furnace. Its carbon reduction principle for the blast furnace is essentially the same as that of injecting hydrogen-rich gas.

[0003] Currently, reducing gas is primarily injected into the furnace through tuyere. However, since high-temperature coal gas and injected pulverized coal are flammable and explosive media, and oxygen-enriched air is a strong oxidizer, improper handling can cause accidents and explosions. Furthermore, the high-temperature coal flow, injected hot air, and injected pulverized coal flow interfere with each other. Improper arrangement can lead to concentrated thermal stress at the front of the tuyere and a reduced raceway area, shortening the tuyere's lifespan and shortening blast furnace production. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a low-carbon blast furnace reducing gas blowing device, which has the characteristics of safe, efficient and stable charging of furnace charge and low-carbon smelting.

[0005] To achieve the above object, the present invention provides the following technical solutions: A low-carbon blast furnace reducing gas injection device includes a tuyere copper sleeve, wherein the tuyere copper sleeve is provided with: An axially extending hot air channel, one end of which is the air outlet end of the tuyere copper sleeve, defined as the tuyere end, and the other end is connected to the hot air surrounding pipe through a pipe; A gas channel, one end of which is connected to the hot air channel and forms an angle of 5-20 degrees with the hot air channel axially, and the blowing direction is the same as the hot air flow direction, and the other end is connected to the gas surrounding pipe through a pipeline; A pulverized coal channel, one end of which is connected to the hot air channel and forms an angle of 5-20 degrees with the axial direction of the hot air channel, and the injection direction is the same as the hot air flow direction, and the other end is connected to the pulverized coal injection device through a pipeline; The axial distance between the gas channel and the end of the tuyere is 70-160 mm; The axial distance between the pulverized coal channel and the end of the tuyere is 70-160 mm.

[0006] Furthermore, the error range of the axial distance between the pulverized coal channel and the end of the tuyere and the axial distance between the gas channel and the end of the tuyere is ±10 mm.

[0007] Furthermore, the gas channel is closer to the tuyere end than the pulverized coal channel, and the difference between the axial distance between the pulverized coal channel and the tuyere end and the axial distance between the gas channel and the tuyere end is 10-60 mm.

[0008] Furthermore, the pulverized coal channel is closer to the tuyere end than the gas channel, and the difference between the axial distance between the pulverized coal channel and the tuyere end and the axial distance between the gas channel and the tuyere end is 10-60 mm.

[0009] Furthermore, the hot air channel, the coal gas channel and the coal powder channel are all lined with an alumina ceramic wear-resistant layer with a thickness of 1.5-2 mm.

[0010] Furthermore, the hot air channel, the gas channel and the pulverized coal channel are all circular, and satisfy the following conditions: the cross-sectional area of the gas channel is 1-15% of that of the hot air channel, and the cross-sectional area of the pulverized coal channel is 1-10% of that of the hot air channel.

[0011] Furthermore, the projected angle of the coal gas channel and the coal powder channel on the radial plane of the hot air channel is 5°-30°, and the blowing direction is the same as the hot air flow direction.

[0012] Furthermore, a cooling water channel is provided inside the tuyere copper sleeve, and a water inlet and a water outlet connected to the cooling water channel are respectively provided on the side wall of the tuyere copper sleeve away from the air outlet end, and the water inlet and the water outlet are externally connected to a flange connection structure.

[0013] Compared with the prior art, the present invention has the following notable features: (1) The use of this injection device for pulverized coal and coal gas injection can increase the maximum combustion temperature and improve the space of the tuyere rotation zone, which is of great significance to the production of blast furnaces.

[0014] (2) In one embodiment, the arrangement of the pulverized coal channel in front and the gas channel in the back results in the lowest temperature on the inner wall of the air duct, which is of great significance for improving the service life of the air outlet. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a simplified structural diagram of the tuyere copper sleeve of the present invention; Figure 2 This is a comparison chart of CFD-DEM three-dimensional numerical simulation of four types of tuyere copper sleeve structures; Figure 3 This is a comparison chart of the combustion temperature at the front end of the tuyere for four types of tuyere copper sleeve structures. DETAILED DESCRIPTION

[0016] To further illustrate various embodiments, the present invention is provided with accompanying drawings. These drawings form part of the present disclosure and are primarily used to illustrate the embodiments and, in conjunction with the relevant description in the specification, to explain the operating principles of the embodiments. By referring to these drawings, one of ordinary skill in the art will understand other possible embodiments and the advantages of the present invention. The components in the figures are not drawn to scale, and similar reference numerals are generally used to represent similar components.

[0017] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1 As shown, the present invention provides a low-carbon blast furnace reducing gas injection device, including a tuyere copper sleeve 4, wherein the tuyere copper sleeve 4 is internally provided with: an axially extending hot air channel 2, one end of which is the air outlet end 5 of the tuyere copper sleeve, and the other end is connected to the hot air surrounding pipe through a pipeline; a gas channel 3 and a pulverized coal channel 1, both of which are 5-30° angles with the axial direction of the hot air channel, and the injection direction is the same as the hot air flow direction; wherein, the connection position of the pulverized coal channel 1 and the hot air channel 2 is close to the air outlet end 5 of the tuyere copper sleeve 4, that is, the tuyere end, and the connection position of the gas channel 3 and the hot air channel 2 is far from the air outlet end 5 of the tuyere copper sleeve 4, the axial distance between the gas channel 3, the pulverized coal channel 1 and the air outlet end 5 (tuyere end) is 70-160mm, and the distance difference between the axial distance between the pulverized coal channel 1 and the tuyere end and the axial distance between the gas channel 3 and the tuyere end is ±10mm.

[0019] In this embodiment, the hot air channel 2, the gas channel 3 and the pulverized coal channel 1 are all lined with wear-resistant and high-temperature resistant bushings. Preferably, the bushings are made of an alumina ceramic wear-resistant layer with a thickness of 1.5-2 mm.

[0020] In this embodiment, the hot air channel 2, the gas channel 3 and the pulverized coal channel 1 are all circular. Preferably, the size relationship among the three satisfies: the cross-sectional area of the gas channel 3 is 1-15% of the hot air channel 2, and the cross-sectional area of the pulverized coal channel 1 is 1-10% of the hot air channel 2.

[0021] In this embodiment, a cooling water channel in the form of a ring structure is provided inside the tuyere copper sleeve 4, and a water inlet and a water outlet connected to the cooling water channel are respectively provided on the side wall of the tuyere copper sleeve 4 away from the air outlet end 5, and the water inlet and the water outlet are externally connected to the flange connection structure.

[0022] Figure 2 Four arrangements of gas and pulverized coal channels on both sides of the hot air channel are given, including: (a) The gas channel and the pulverized coal channel are opposite: the connection positions of the gas channel, the pulverized coal channel and the hot air channel are consistent, and the axial angles of the gas channel, the pulverized coal channel and the hot air channel are consistent, which can be 5-20 degrees; (b) The gas channel and the pulverized coal channel are eccentrically opposed: The connection positions of the gas channel, the pulverized coal channel, and the hot air channel are consistent, and the axial angles of the gas channel, the pulverized coal channel, and the hot air channel are inconsistent, with a distance difference of 5-10° between the two. (c) The pulverized coal channel is in front and the gas channel is in the back; the difference in axial distance between the pulverized coal channel and the end of the tuyere and the axial distance between the gas channel and the end of the tuyere is 10-60 mm.

[0023] (d) The gas channel is in front and the pulverized coal channel is in the back; the difference in axial distance between the pulverized coal channel and the end of the tuyere and the axial distance between the gas channel and the end of the tuyere is 10-60 mm.

[0024] Then three-dimensional numerical simulations of the four structures were carried out using CFD-DEM.

[0025] like Figure 2 As shown, from the results of digital simulation, the temperature of the inner wall of the air duct in the method of the present application with the pulverized coal channel in front and the gas channel in the back is the lowest, which is of great significance for improving the life of the air duct.

[0026] From the results of digital simulation, it can be seen that the arrangement with the pulverized coal channel in front and the gas channel in the back has the lowest temperature on the inner wall of the air duct, which is of great significance for improving the service life of the air outlet.

[0027] Combine Figure 3 As shown in the figure, from the combustion situation of the tuyere vortex zone, the traditional method of placing the gas channel and the pulverized coal channel opposite each other is Figure 3 (a) The highest temperature in the tuyere vortex zone is 2141°C. The temperatures in the tuyere vortex zones formed by other schemes are all higher. Figure 3 (b) The maximum temperature in the raceway is 2387°C, Figure 3 (c) The maximum temperature in the raceway is 2170°C, Figure 3 (d) The maximum temperature of the raceway is 2749°C. All three methods can increase the maximum combustion temperature, that is, they can improve the space of the tuyere raceway, which is of great significance to the production of blast furnaces.

[0028] Although the present invention has been particularly shown and described in conjunction with preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims, and all such changes are within the scope of protection of the present invention.

Claims

1. A low-carbon blast furnace reducing gas injection device, characterized in that: It includes a copper tuyere sleeve, the interior of which is provided with: An axially extending hot air channel, one end of which is the air outlet end of the tuyere copper sleeve, defined as the tuyere end, and the other end is connected to the hot air surrounding pipe through a pipe; A gas channel, one end of which is connected to the hot air channel and forms an angle of 5-20 degrees with the hot air channel axially, and the blowing direction is the same as the hot air flow direction, and the other end is connected to the gas surrounding pipe through a pipeline; A pulverized coal channel, one end of which is connected to the hot air channel and forms an angle of 5-20 degrees with the axial direction of the hot air channel, and the injection direction is the same as the hot air flow direction, and the other end is connected to the pulverized coal injection device through a pipeline; The axial distance between the gas channel and the end of the tuyere is 70-160 mm; The axial distance between the pulverized coal channel and the end of the tuyere is 70-160 mm.

2. The low-carbon blast furnace reducing gas injection device according to claim 1, characterized in that: The error range of the axial distance between the pulverized coal channel and the end of the tuyere and the axial distance between the gas channel and the end of the tuyere is ±10 mm.

3. The low-carbon blast furnace reducing gas injection device according to claim 1, characterized in that: The gas channel is closer to the tuyere end than the pulverized coal channel, and the difference between the axial distance between the pulverized coal channel and the tuyere end and the axial distance between the gas channel and the tuyere end is 10-60 mm.

4. The low-carbon blast furnace reducing gas injection device according to claim 1, characterized in that: The pulverized coal channel is closer to the tuyere end than the gas channel, and the difference between the axial distance between the pulverized coal channel and the tuyere end and the axial distance between the gas channel and the tuyere end is 10-60 mm.

5. The low-carbon blast furnace reducing gas injection device according to claim 1, characterized in that: The hot air channel, the coal gas channel and the coal powder channel are all lined with an alumina ceramic wear-resistant layer with a thickness of 1.5-2 mm.

6. The low-carbon blast furnace reducing gas injection device according to claim 1, characterized in that: The hot air channel, gas channel and pulverized coal channel are all circular and meet the following requirements: the cross-sectional area of the gas channel is 1-15% of that of the hot air channel, and the cross-sectional area of the pulverized coal channel is 1-10% of that of the hot air channel.

7. The low-carbon blast furnace reducing gas injection device according to claim 1, characterized in that: The projected angle of the coal gas channel and the coal powder channel on the radial plane of the hot air channel is 5°-30°, and the blowing direction is the same as the hot air flow direction.

8. The low-carbon blast furnace reducing gas injection device according to claim 1, characterized in that: A cooling water channel is provided inside the tuyere copper sleeve, and a water inlet and a water outlet connected to the cooling water channel are respectively provided on the side wall of the tuyere copper sleeve away from the air outlet end, and the water inlet and the water outlet are externally connected to a flange connection structure.

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