A multi-layer structure heat-insulating material heat-insulating brick for a rotary kiln

Abstract

This invention relates to the field of refractory brick technology, specifically a multi-layered insulating brick for rotary kilns. The brick includes a brick body with hollowed-out areas along its thickness direction, filled with insulating material. A back groove is formed on the surface of the brick body facing away from the kiln interior, extending along the thickness direction of the brick body. This back groove is filled with a back filler for heat insulation. This insulating brick possesses the advantages of magnesia-alumina bricks, such as good thermal shock stability and a high load softening temperature, while also exhibiting strong heat insulation capabilities, significantly reducing energy consumption in the transition zone.

Description

Technical Field

[0001] This invention relates to the field of refractory brick technology, and in particular to a multi-layered thermal insulation material for rotary kilns. Background Technology

[0002] With the rapid development of the global cement industry, refractory bricks for cement kilns have made significant progress in both variety and quality. Different parts of a cement rotary kiln have varying atmospheres and operating temperatures; therefore, different refractory bricks are used in different zones, such as the decomposition zone, transition zone, and cooling zone. Refractory bricks in the firing zone require not only high refractoriness, strong resistance to slag erosion, and good thermal shock resistance, but also high high-temperature strength and cost-effectiveness. Currently, magnesia-alumina bricks are commonly used in the transition zone of cement rotary kilns due to their good thermal shock stability and high load softening temperature. However, the problem of their high thermal conductivity and poor insulation remains unresolved, leading to increased energy consumption and resource waste in the transition zone. These issues seriously hinder technological progress in the calcined cement clinker industry and have become a major obstacle to the development of the cement industry. Summary of the Invention

[0003] To address the aforementioned problems, this invention proposes a multi-layered thermal insulation material for rotary kilns. This thermal insulation material possesses the advantages of good thermal shock stability and high load softening temperature of magnesium-aluminum bricks, while also exhibiting strong heat preservation capabilities, significantly reducing energy consumption in the transition zone.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A multi-layered thermal insulation material for rotary kilns includes a brick body with a hollow area in its thickness direction. The hollow area is filled with thermal insulation material. A back groove is formed on the surface of the brick body facing away from the inside of the kiln body and extends through the thickness direction of the brick body. The back groove is filled with a back filler for heat preservation.

[0006] Preferably, the hollow area includes a first hollow area of ​​an equilateral triangle located in the middle of the brick body, with one apex of the first hollow area facing the surface where the back groove is located. Two second hollow areas are also provided between the first hollow area and the surface where the back groove is located. The second hollow areas are right triangles. The two second hollow areas are respectively arranged on the left and right sides of the first hollow area and are symmetrically arranged. The longest side of the second hollow area is approximately parallel to the side of the first hollow area adjacent to it, and the acute angle of the second hollow area near the surface where the back groove is located is 60°.

[0007] Preferably, the first and / or second hollow areas are filled with hollow microspheres made of heat-resistant material.

[0008] Preferably, the first and second hollow areas occupy 20%-25% of the surface area.

[0009] Preferably, the brick body has dimensions of 220mm*198mm*65mm, the side length of the first hollow area is 14cm-16cm, and the length of the longest side of the second hollow area is 8cm-10cm.

[0010] Preferably, the porosity of the brick body is generally 15% to 18%, and it is made by firing high-purity magnesia sand of different particle sizes, fused magnesium aluminum spinel, fused magnesia sand, etc. in proportion, with a load softening temperature of over 1580℃.

[0011] Preferably, there are 3-6 back grooves.

[0012] Preferably, the back groove opening is 35mm wide, 1cm-2cm deep, and has a thickness equal to the brick thickness, with an interval of 8mm-9mm between two adjacent back grooves.

[0013] Preferably, the total area of ​​the back groove openings accounts for 80%-85% of the area of ​​the surface where the back groove openings are located.

[0014] Preferably, the back filler has two layers of thermal insulation material: a layer of aerogel thermal insulation material with a thickness of 1cm-1.5cm, a thermal conductivity of about 0.02W / (m·K), and an operating temperature of 1000℃ near the bottom of the back groove; and a layer of aerogel felt with a thickness of 0.5-1cm, a thermal conductivity of about 0.02W / (m·K), and an operating temperature of 600℃ near the opening of the back groove. The aerogel thermal insulation material and the aerogel felt are bonded together with refractory mortar.

[0015] The beneficial effects of using this invention are:

[0016] This invention discloses a structural insulation material for rotary kilns, an insulating brick that, while meeting the load softening temperature requirement, also possesses high thermal insulation capabilities, reducing energy consumption in the transition zone of the rotary kiln. The brick body employs an internal hollow microsphere structure to maximize insulation while ensuring structural strength. This insulating brick utilizes multi-layered insulation materials to minimize costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of insulating bricks used in rotary kilns, which are multi-layered insulating materials.

[0018] The reference numerals in the figures include:

[0019] 10-Brick body, 11-First hollow area, 12-Second hollow area, 13-Back groove, 21-First filler, 22-Second filler, 30-Back filler. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this technical solution clearer, the following detailed description, in conjunction with specific embodiments, further illustrates this technical solution. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of this technical solution.

[0021] Example 1

[0022] like Figure 1 As shown, this embodiment proposes a multi-layered thermal insulation material for rotary kilns, comprising a brick body 10. The brick body 10 has a hollowed-out area along its thickness direction, which is filled with thermal insulation material. A back groove 13 is formed on the surface of the brick body 10 facing away from the kiln interior, and this back groove 13 extends along the thickness direction of the brick body 10. The back groove 13 is filled with a back filler 30 for heat preservation. Figure 1 Side A is the side facing inwards from the kiln, and side B is the outside.

[0023] The hollow area includes a first hollow area 11, an equilateral triangle located in the middle of the brick body 10. One apex of the first hollow area 11 faces the surface where the back groove 13 is located. Two second hollow areas 12 are also provided between the first hollow area 11 and the surface where the back groove 13 is located. The second hollow areas 12 are right-angled triangles, respectively located on the left and right sides of the first hollow area 11 and arranged symmetrically. The longest side of the second hollow area 12 is approximately parallel to the side of the adjacent first hollow area 11, and the acute angle of the second hollow area 12 near the surface where the back groove 13 is located is 60°. Both the first hollow area 11 and the second hollow area 12 can be understood as through grooves.

[0024] In this application, the porosity of the brick body 10 is generally 15% to 18%, and it is made by firing high-purity magnesia sand of different particle sizes, fused magnesium aluminum spinel, fused magnesia sand, etc. in proportion. The load softening temperature is above 1580℃, and the size of the brick body 10 is 220mm*198mm*65mm.

[0025] The side length of the first hollow area 11 is 14cm-16cm; the length of the longest side of the second hollow area 12 is 8cm-10cm.

[0026] The first hollow area 11 and the second hollow area 12 are filled with hollow microspheres made of heat-resistant material. The function of the hollow microspheres is to slow down the heat transfer rate. Referring to the first hollow area 11 and the second hollow area 12, their shapes can form irregular heat-insulating areas on the surface of the brick body 10. After the first hollow area 11 and the second hollow area 12 are filled with hollow microspheres, heat can be effectively blocked by the hollow microspheres, preventing heat from being rapidly transferred to the outside of the rotary kiln through the brick body 10.

[0027] In this embodiment, both the first filler 21 and the second filler 22 are hollow microspheres. In other embodiments, the first filler 21 and the second filler 22 may be made of different heat insulation materials. Regardless of the heat insulation material used, it is sufficient to meet the heat resistance and heat insulation requirements of the brick body 10, but hollow microspheres are preferred.

[0028] The first hollowed-out area 11 and the second hollowed-out area 12 occupy 20%-25% of the surface area.

[0029] Regarding the back groove 13, there are 3-6 back grooves 13. The opening width of the back groove 13 is 35mm, the depth is 1cm-2cm, and the thickness is equal to the thickness of the brick body 10. The interval between two adjacent back grooves 13 is 8mm-9mm. The total area of ​​the openings of the back grooves 13 accounts for 80%-85% of the area of ​​the surface where the openings of the back grooves 13 are located.

[0030] The back filler 30 has two layers of insulation material. Near the bottom of the back groove 13, there is a 1-1.5 cm thick layer of aerogel insulation material with a thermal conductivity of approximately 0.02 W / (m·K) and an operating temperature of 1000℃. Near the opening of the back groove 13, there is a 0.5-1 cm thick layer of aerogel felt insulation material with a thermal conductivity of approximately 0.02 W / (m·K) and an operating temperature of 600℃. The aerogel insulation material and the aerogel felt are bonded together with refractory mortar. The placement of aerogel insulation material within the back groove 13 and the hollow microspheres inside the brick body 10 effectively reduces energy consumption in the transition zone.

[0031] Example 2

[0032] This embodiment describes the method for determining the heat flow of the multi-layered thermal insulation material rotary kiln insulation bricks and the rotary kiln as a whole in Embodiment 1 above, including the following steps:

[0033] Determine the heat flow of each brick.

[0034] The brick body 10 is made of magnesium aluminate spinel brick. The thermal conductivity λ1 of the magnesium aluminate spinel brick is approximately 3.3-3.5 W / (m·K), and the thermal conductivity λ2 of the aerogel insulation material is approximately 0.02 W / (m·K). The heat flow rate of this invention is calculated using the heat flow rate formula, which is as follows:

[0035]

[0036] Where: Φ - heat flow rate;

[0037] t1 - Temperature of high-temperature surface A;

[0038] t2 - Temperature of low-temperature surface B;

[0039] δ - Thickness of the insulation material;

[0040] λ - Thermal conductivity of the insulation material;

[0041] F - Area of ​​the insulation material;

[0042]

[0043] Where: R - thermal resistance;

[0044] δ - Thickness of the insulation material;

[0045] λ - Thermal conductivity of the insulation material;

[0046] F - Area of ​​the insulation material;

[0047] The thermal resistance of the magnesium aluminum spinel brick is R1, the thermal resistance of the aerogel insulation material is R2, and the thermal resistance of the internal hollow microspheres is R3.

[0048] Substitute into the formula:

[0049] The heat flow rate of each brick is calculated to be Φ1.

[0050] The heat flow rate of each magnesium aluminate spinel brick is determined. The thermal conductivity λ1 of the magnesium aluminate spinel brick is approximately 3.3–3.5 W / (m·K). The heat flow rate of the magnesium aluminate spinel brick is calculated using the heat flow rate formula, which is as follows:

[0051]

[0052] Where: Φ2 - heat flow rate;

[0053] t1 - Temperature of high-temperature surface A;

[0054] t2 - Temperature of low-temperature surface B;

[0055] The thickness of δ-magnesium aluminum spinel bricks;

[0056] Thermal conductivity of λ-magnesium aluminum spinel bricks;

[0057] The area of ​​F-magnesium aluminum spinel bricks;

[0058] The heat flow rate of the magnesium aluminum spinel brick is calculated to be Φ2.

[0059] Finally, the energy-saving performance of this invention and the magnesium-aluminum spinel brick is calculated. This is expressed by the following formula:

[0060]

[0061] Where: C - energy saving level;

[0062] Φ1 - Heat flow rate of the present invention;

[0063] Heat flow of Φ2-magnesium aluminum spinel brick

[0064] The energy-saving level is calculated to be C.

[0065] Calculation of heat flow for the entire cement rotary kiln;

[0066]

[0067] This invention relates to refractory bricks for rotary kilns, which utilize different structures and filled with different insulating materials to increase insulation capacity. While meeting high load softening temperatures, it also ensures heat preservation, and can be applied to the transition and firing zones of rotary kilns.

[0068] The above content is only a preferred embodiment of the present invention. For those skilled in the art, many changes can be made in the specific implementation and application scope based on the ideas of the present invention. As long as these changes do not depart from the concept of the present invention, they all fall within the protection scope of this patent.

Claims

1. A multi-layered thermal insulation material brick for rotary kilns, characterized in that: The brick body has a hollow area in its thickness direction, which is filled with heat insulation material. The brick body has a back groove on the side surface facing away from the kiln body, and the back groove runs through the thickness direction of the brick body. The back groove is filled with a back filler for heat preservation. The hollow area includes a first hollow area, which is an equilateral triangle located in the middle of the brick body. One of the apexes of the first hollow area faces the back groove. There are also two second hollow areas between the first hollow area and the back groove. The second hollow areas are right triangles. The two second hollow areas are respectively set on the left and right sides of the first hollow area and are arranged symmetrically. The longest side of the second hollow area is roughly parallel to the side of the first hollow area adjacent to it, and the acute angle of the second hollow area near the back groove is 60°. The first and / or second hollow areas are filled with hollow microspheres made of heat-resistant material; The back filler has two layers of thermal insulation material. The first layer, near the bottom of the back groove, is an aerogel thermal insulation material with a thickness of 1cm-1.5cm, a thermal conductivity of 0.02W / m·K, and an operating temperature of 1000℃. The second layer, near the opening of the back groove, is an aerogel felt with a thickness of 0.5-1cm, a thermal conductivity of 0.02W / m·K, and an operating temperature of 600℃. The aerogel thermal insulation material and the aerogel felt are bonded together with refractory mortar.

2. The multi-layer structure heat insulation material brick for rotary kilns according to claim 1, characterized in that: The first and second hollow areas occupy 20%-25% of the surface area.

3. The multi-layer structure heat insulation material brick for rotary kilns according to claim 1, characterized in that: The brick has dimensions of 220mm*198mm*65mm, the side length of the first hollow area is 14cm-16cm, and the length of the longest side of the second hollow area is 8cm-10cm.

4. The multi-layer structure heat insulation material brick for rotary kilns according to claim 1, characterized in that: The porosity of the brick is generally 15%~18%, and it is made by firing high-purity magnesia sand of different particle sizes, fused magnesium aluminum spinel, and fused magnesia sand in proportion. The load softening temperature is above 1580℃.

5. The multi-layer structure heat insulation material brick for rotary kilns according to claim 1, characterized in that: There are 3-6 back grooves.

6. The multi-layer structure heat insulation material brick for rotary kilns according to claim 1, characterized in that: The back groove opening is 35mm wide, 1cm-2cm deep, and has a thickness equal to the brick thickness. The interval between two adjacent back grooves is 8mm-9mm.

7. The multi-layer structure heat insulation material brick for rotary kilns according to claim 6, characterized in that: The total area of ​​the back groove openings accounts for 80%-85% of the area of ​​the surface where the back groove openings are located.

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