A composite hollow cavity lining for a blast furnace direct blowing pipe and its manufacturing process

Abstract

The present invention belongs to the technical field of metal smelting, and discloses a composite hollow cavity lining for a blast furnace direct injection pipe. The inner layer of the composite hollow cavity lining is made of 95 alumina ceramic material, and the outer layer is a nano thermal insulation board. The nano thermal insulation board is pasted on the outer surface of the frustum-shaped hollow cavity made of the 95 alumina ceramic material. In the present invention, four layers of nano thermal insulation boards are pasted on the outer surface of the frustum-shaped hollow cavity, playing a role in heat insulation and heat preservation, making the inner cavity of the composite hollow cavity lining smooth as a whole, having good heat insulation performance on the outer wall, greatly improving the overall strength and high-temperature performance, reducing the occurrence of the phenomenon of the steel shell turning red, and doubling the service life compared with that before transformation.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal smelting, and relates to a composite hollow cavity inner lining for a blast furnace tuyere pipe and a manufacturing process thereof. Background Art

[0002] During the process of blast furnace ironmaking, the function of the tuyere pipe of the blast furnace air supply device is to send hot air at 1200 - 1350 °C heated by the hot blast stove into the blast furnace. The tuyere pipe consists of four parts: the end head, the pipe body, the injection pipe, and the tail flange. The tail is connected to the elbow pipe, and the end head is closely connected to the tuyere. Due to its small structural size, the space for pouring heat-insulating materials is limited, and the working conditions are characterized by high air temperature, high air pressure, and high flow rate. Therefore, it becomes the throat component with the worst working conditions. Generally, it is required that the tuyere pipe has the characteristics of high temperature resistance, erosion resistance, small thermal conductivity, and strong thermal shock resistance. When the diameter of the tuyere pipe is small, a single-layer refractory inner lining structure is generally used, and the problems of service life and heat insulation effect are more prominent; when the diameter of the tuyere pipe is large, a multi-layer refractory inner lining structure is used, but the construction is very difficult due to its complex structure; and at the same time, due to the strong intersection of the tuyere pipe and the related connecting equipment of the blast furnace, the one-time investment is large. Therefore, once its external dimensions are designed, they will not be easily changed unless there is a major overhaul of the furnace campaign or adjustment is really needed.

[0003] The currently used inner lining pipe materials generally adopt high-alumina or corundum refractory castables. These materials do not match the metal pipe. As the air temperature rises, the inner lining of the new tuyere pipe falls off soon after use, and the steel shell of the tuyere pipe turns red. The tuyere pipe burns through from time to time. Under the action of increasing air temperature, air velocity, and oxygen enrichment rate, the service life of the tuyere pipe is further shortened, and the average service life is only 2 - 5 months. It needs to be frequently replaced during the production process, which affects the normal production of the blast furnace. Summary of the Invention

[0004] Aiming at the problem of the short service life of the inner lining of the tuyere pipe, the present invention provides a composite hollow cavity inner lining for a blast furnace tuyere pipe and a manufacturing process thereof, so that the inner cavity of the composite hollow cavity inner lining is smooth as a whole, the outer wall has good heat insulation performance, the overall strength and high-temperature performance are greatly improved, the occurrence of the steel shell turning red is reduced, and the service life is doubled compared with that before transformation.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a composite hollow cavity inner lining for a blast furnace tuyere pipe. The inner layer of the composite hollow cavity inner lining is made of 95% alumina ceramic material, and the outer layer is a nano-insulation board, and the nano-insulation board is pasted on the outer surface of the frustum-shaped hollow cavity made of the 95% alumina ceramic material.

[0007] The present invention also provides a manufacturing process for the composite hollow cavity inner lining for a blast furnace tuyere pipe, including the following steps:

[0008] 1) According to the inner lining size of the blast furnace direct injection pipe, a frustum-shaped hollow cavity is made of 95 alumina ceramic material;

[0009] 2) According to the inner lining size of the blast furnace direct injection pipe, the nano-insulation board is cut into four isosceles trapezoidal boards with different sizes;

[0010] 3) Stand up the frustum-shaped hollow cavity, and splice and paste the four isosceles trapezoidal boards on the outer surface of the frustum-shaped hollow cavity layer by layer in four layers to obtain a composite hollow cavity inner lining. When pasting each layer, a space of 50 mm high is reserved from the bottom end and the top end of the frustum-shaped hollow cavity, and a space of 50 mm wide is reserved at the three-way port of the coal injection gun;

[0011] 4) Clean the floating ash on the inner wall of the blast furnace direct injection pipe, apply refractory glue on the inner wall of the blast furnace direct injection pipe, place the blast furnace direct injection pipe upside down in the pit, tear off the surface wax paper of the outermost isosceles trapezoidal board of the composite hollow cavity inner lining, hoist the composite hollow cavity inner lining into the direct injection pipe, and adjust the angle between the composite hollow cavity inner lining and the three-way port of the coal injection gun to be consistent;

[0012] 5) Pour corundum refractory material into the reserved spaces at the bottom end and the top end of the frustum-shaped hollow cavity and at the three-way port of the coal injection gun, and let it dry naturally for 24 h and then dry it in an oven for 24 h.

[0013] In a technical solution, the lengths of the upper base and the lower base of the first isosceles trapezoidal board in step 2) are 91 mm and 100 mm respectively, the lengths of the upper base and the lower base of the second isosceles trapezoidal board are 77 mm and 91 mm respectively, the lengths of the upper base and the lower base of the third isosceles trapezoidal board are 77 mm and 63 mm respectively, and the lengths of the upper base and the lower base of the fourth isosceles trapezoidal board are 73 mm and 95 mm respectively.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] The present invention uses 95 alumina ceramic material to make a frustum-shaped hollow cavity, which is wear-resistant and fire-resistant; four layers of nano-insulation boards are pasted on the outer surface of the frustum-shaped hollow cavity to play a role in heat insulation and heat preservation, making the inner cavity of the composite hollow cavity inner lining smooth as a whole, with good heat insulation performance on the outer wall, greatly improving the overall strength and high-temperature performance, reducing the occurrence of the steel shell turning red, and doubling the service life compared with that before transformation. In addition, corundum refractory material is poured into the reserved spaces at the bottom end and the top end of the frustum-shaped hollow cavity and at the three-way port of the coal injection gun, making the inner lining better adhere to the inner wall of the direct injection pipe and not easy to fall off. Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the composite frustum-shaped hollow cavity inner lining of the present invention.

[0017] Figure 2 It is for the present invention Figure 1 The sectional structure schematic diagram of A-A in it.

[0018] Figure 3 It is a structural schematic diagram of a blast furnace direct blowing pipe.

[0019] Reference numerals in the drawings: 1 is 95% alumina ceramic material, 2 is a nano thermal insulation board. Specific implementation manners

[0020] The following embodiments are used to illustrate the present invention, but are not used to limit the protection scope of the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. The test methods in the following embodiments are conventional methods unless otherwise specified.

[0021] Embodiment 1

[0022] As Figure 1 and Figure 2 shown, the inner layer of the composite frustum-shaped hollow cavity lining of the present invention is 95% alumina ceramic material 1, and the outer layer is nano thermal insulation board 2. The nano thermal insulation board 2 is pasted on the outer surface of the frustum-shaped hollow cavity made of 95% alumina ceramic material 1. It should be noted that the nano thermal insulation board adopted in the present invention is the nano thermal insulation board disclosed in the authorized publication number CN102853211B. It mainly includes nano thermal insulation blocks, PE films and pressure-sensitive tapes. The PE films are wrapped outside the nano thermal insulation blocks, and the pressure-sensitive tapes cover the surfaces of the PE films. The nano thermal insulation blocks are made of 30-60% fumed silica particles, 30-65% nano zirconia and 1-5% inorganic fibers. The heat preservation effect of this nano thermal insulation board is twice that of conventional heat insulation materials.

[0023] As Figure 2 shown, the direct blowing pipe is welded into an integral steel shell structure by a flange 11, a pipe body 12, a connecting sleeve 13, a sealing plate 14, a connecting pipe 15 and a coal injection flange 16. According to the above direct blowing pipe structure, a manufacturing process of a composite hollow cavity lining for a blast furnace direct blowing pipe of the present invention includes the following steps:

[0024] 1) According to the inner lining size of the blast furnace direct blowing pipe, a frustum-shaped hollow cavity is made of 95% alumina ceramic material. The upper bottom diameter of the frustum-shaped hollow cavity is 185 mm and the lower bottom diameter is 400 mm.

[0025] 2) According to the inner lining size of the blast furnace direct blowing pipe, the nano thermal insulation board is cut into four isosceles trapezoidal plates with different sizes. The upper and lower bottom lengths of the first isosceles trapezoidal plate are 91 mm and 100 mm respectively, the upper and lower bottom lengths of the second isosceles trapezoidal plate are 77 mm and 91 mm respectively, the upper and lower bottom lengths of the third isosceles trapezoidal plate are 77 mm and 63 mm respectively, and the upper and lower bottom lengths of the fourth isosceles trapezoidal plate are 73 mm and 95 mm respectively.

[0026] 3) Stand up the frustum-shaped hollow cavity, and splice and paste four isosceles trapezoidal plates on the outer surface of the frustum-shaped hollow cavity layer by layer in four layers to obtain a composite hollow cavity lining. When pasting each layer, reserve a space of 50 mm in height from the bottom end and the top end of the frustum-shaped hollow cavity, and reserve a space of 50 mm in width at the three-way port of the coal injection lance;

[0027] 4) Clean the floating ash on the inner wall of the blast furnace direct injection pipe, apply refractory glue on the inner wall of the blast furnace direct injection pipe, place the blast furnace direct injection pipe upside down in the pit, tear off the surface wax paper of the outermost isosceles trapezoidal plate of the composite hollow cavity lining, hoist the composite hollow cavity lining into the direct injection pipe, and adjust the angle between the composite hollow cavity lining and the three-way port of the coal injection lance to be consistent.

[0028] 5) Pour corundum refractory material into the reserved spaces at the bottom end and the top end of the frustum-shaped hollow cavity and at the three-way port of the coal injection lance, and let it dry naturally for 24 h and then bake it for 24 h.

[0029] The present invention uses 95 alumina ceramic material to make the frustum-shaped hollow cavity, which is wear-resistant and refractory; four layers of nano-insulation boards are pasted on the outer surface of the frustum-shaped hollow cavity, playing a role in heat insulation and reducing the occurrence of the phenomenon that the steel shell turns red, greatly improving the overall lining strength and high-temperature performance, and doubling the service life compared with that before transformation. In addition, pouring corundum refractory material into the reserved spaces at the bottom end and the top end of the frustum-shaped hollow cavity and at the three-way port of the coal injection lance makes the lining better adhere to the inner wall of the direct injection pipe and not easy to fall off.

[0030] The above-mentioned embodiments are only the preferred embodiments of the present invention, which are only used to explain the present invention and do not limit the scope of implementation of the present invention. For those skilled in the art of this technology, of course, other implementation manners can be easily made through replacement or change according to the technical content disclosed in this specification. Therefore, all changes and improvements made on the principle of the present invention should be included within the scope of the patent application of the present invention.

Claims

1. A manufacturing process for the composite hollow cavity inner lining of a blast furnace tuyere pipe, characterized in that, it comprises the following steps: 1) According to the inner lining size of the blast furnace tuyere pipe, a frustum-shaped hollow cavity is made of 95 alumina ceramic material; 2) According to the inner lining size of the blast furnace tuyere pipe, the nano-insulation board is cut into four isosceles trapezoidal boards with different sizes. The upper and lower base lengths of the first isosceles trapezoidal board are 91 mm and 100 mm respectively, the upper and lower base lengths of the second isosceles trapezoidal board are 77 mm and 91 mm respectively, the upper and lower base lengths of the third isosceles trapezoidal board are 77 mm and 63 mm respectively, and the upper and lower base lengths of the fourth isosceles trapezoidal board are 73 mm and 95 mm respectively; 3) Stand up the frustum-shaped hollow cavity, and splice and paste the four isosceles trapezoidal boards on the outer surface of the frustum-shaped hollow cavity in four layers in turn to obtain the composite hollow cavity inner lining. When pasting each layer, a space with a height of 50 mm is reserved at the bottom and top of the frustum-shaped hollow cavity, and a space with a width of 50 mm is reserved at the three-way port of the coal injection gun; 4) Clean the floating ash on the inner wall of the blast furnace tuyere pipe, apply refractory glue on the inner wall of the blast furnace tuyere pipe, place the blast furnace tuyere pipe upside down in the pit, tear off the surface wax paper of the outermost isosceles trapezoidal board of the composite hollow cavity inner lining, hoist the composite hollow cavity inner lining into the tuyere pipe, and adjust the angle between the composite hollow cavity inner lining and the three-way port of the coal injection gun to be consistent; 5) Pour corundum refractory material into the reserved spaces at the bottom and top of the frustum-shaped hollow cavity and at the three-way port of the coal injection gun, and let it dry naturally for 24 h and then dry it in an oven for 24 h.

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