Convex body structure for improving radiation area and emissivity of kiln and construction method of convex body structure

Abstract

The invention provides a convex body structure for improving the radiation area and emissivity of a kiln and a construction method thereof.The kiln comprises the inner surface of a kiln wall and the inner surface of a kiln top and comprises a plurality of convex bodies, the wall face and the kiln top of the kiln wall are covered with the convex bodies, the convex bodies are pyramids, and the convex bodies are arranged in the kiln wall. And the bottom end of the convex body is connected with the furnace wall or the furnace top. By arranging the convex bodies on the wall surface and the furnace top of the furnace wall, the radiation area is effectively increased, the emissivity is improved, the radiation shielding effect is eliminated, the uniformity of a thermal field in the furnace is ensured, and the energy consumption is reduced. Modularized construction is adopted for the convex body, the installation process is simplified, the field adjustment cost is reduced, and the construction stability is improved.

Description

Technical Field

[0001] This invention relates to the field of energy-saving technology for industrial heating furnaces, and in particular to a convex structure and its construction method for improving the radiation area and emissivity of a kiln. Background Technology

[0002] Industrial heating furnaces are core equipment in the steel rolling industry, accounting for 30%-40% of total process energy consumption. With the advancement of global "dual-carbon" goals and rising energy costs, reducing heating furnace energy consumption has become a key issue in the industrial sector. As the core interface for heat exchange in the furnace, the furnace wall's radiative heat transfer efficiency directly determines energy utilization—radiative heat transfer accounts for over 70% of total heat transfer at high temperatures. Therefore, improving the radiative performance of the furnace wall is a crucial breakthrough for energy conservation.

[0003] Most existing industrial heating furnaces have flat furnace walls, which have the following problems:

[0004] 1. Due to the limited effective radiation area, the emissivity of refractory materials is mostly below 0.8.

[0005] 2. Poor uniformity of thermal field: The planar radiation direction is unidirectional, and local high temperature or low temperature zones are easily formed in the furnace, resulting in uneven heating of the heated workpiece (such as steel billet) and increasing the scrap rate (according to industry data, the product qualification rate of traditional kilns is reduced by 5%-15% due to uneven thermal field).

[0006] 3. Limitations of refractory material performance: Traditional furnace walls mostly use clay bricks, high-alumina bricks, or ordinary refractory castables. At high temperatures above 800℃, due to the stabilization of the crystal structure, the emissivity of these materials decreases with increasing temperature (e.g., the emissivity of high-alumina bricks drops to 0.6-0.7 at 1000℃). Furthermore, after long-term use, they are prone to thermal shock cracking and surface oxidation and peeling, which further reduces radiation efficiency.

[0007] 4. Significant heat loss: The planar structure results in a high proportion of radiant energy being scattered out of the furnace, with heat loss from the furnace wall surface accounting for 10%-20% of the total energy consumption, especially in intermittent kilns.

[0008] To address these issues, the industry has tried various improvement methods, but all have shortcomings:

[0009] 1. Coating reinforcement: Applying a high emissivity coating (such as silicon carbide or zirconia-based coating) to the surface of the flat furnace wall can increase the emissivity to 0.85-0.9 in the short term. However, the coating has poor thermal expansion matching with the substrate at high temperatures, making it easy to peel off (lifespan is usually <3 months) and resulting in high maintenance costs.

[0010] 2. Structural optimization: The radiation area can be expanded by adding radiation tubes, reflectors and other components, but this will increase the space occupancy rate inside the furnace, enhance airflow disturbance, increase power consumption, and make the structure complex and prone to dust accumulation, which will affect the long-term effect.

[0011] 3. Material upgrade: Rare earth refractory materials such as cerium oxide and lanthanum oxide are used to improve emissivity, but these materials are expensive (5-10 times that of ordinary refractory materials) and have insufficient high-temperature stability (they are prone to sintering and deterioration above 1600℃).

[0012] For the reasons mentioned above, there is an urgent need for a convex structure and its construction method to improve the radiation area and emissivity of a kiln. Summary of the Invention

[0013] The purpose of this invention is to provide a convex structure and its construction method for improving the radiation area and emissivity of a kiln. The convex structure is simple, has a high radiation area and emissivity, good energy-saving effect, and long service life, which effectively improves the product quality and production efficiency of the kiln and reduces energy consumption.

[0014] To achieve the above objectives, the present invention provides the following technical solution:

[0015] A convex structure for improving the radiation area and emissivity of a kiln, the kiln including a furnace wall and a furnace roof, including a plurality of convex bodies, the plurality of convex bodies covering the inner surface of the furnace wall and the inner surface of the furnace roof, the convex bodies being pyramidal, the bottom end of the convex bodies being connected to the furnace wall or the furnace roof.

[0016] Furthermore, in the aforementioned convex structure for improving the radiation area and emissivity of the kiln, the convex body is a regular triangular pyramid with a base side length of 100mm-200mm, a height of 50mm-100mm, and an angle of 60° between the side of the regular triangular pyramid and the surface of the furnace wall or the furnace top.

[0017] Furthermore, in the aforementioned convex structure for improving the radiation area and emissivity of the kiln, the convex body is a regular square pyramid with a base side length of 100mm-200mm, a height of 80mm-150mm, and a apex angle of the side face of the regular square pyramid of 90°-120°.

[0018] Furthermore, in the aforementioned convex structure for improving the radiation area and emissivity of the kiln, the convex bodies are arranged in an equilateral triangle pattern on the wall surface of the furnace wall and the furnace top, and the distance between the center points of the bottom surfaces of two adjacent convex bodies is 1.0-1.5 times the height of the convex body.

[0019] Furthermore, in the aforementioned convex structure for improving the radiation area and emissivity of the kiln, the convex is made of LaAlO3-based composite material. The chemical composition of the convex is: LaAlO3 70-85wt%, CaO 5-10wt%, Fe2O3 3-8wt%, Y2O3-stabilized ZrO 25-15wt%. The LaAlO3-based composite material has an average emissivity ≥0.95 in the 0.76-2.5μm wavelength band and a coefficient of thermal expansion of 6.5-7.5×10⁻⁶. -6 / ℃.

[0020] Furthermore, in the aforementioned convex structure for improving the radiation area and emissivity of the kiln, the bottom end of the convex is embedded in a mortise in the furnace wall or the furnace top, the depth of the convex embedded in the furnace wall and the furnace top is 1 / 3 to 1 / 2 of the height of the convex, and the fitting gap between the bottom end of the convex and the mortise is 0.5mm to 1.0mm.

[0021] Furthermore, in the aforementioned convex structure for improving the radiation area and emissivity of the kiln, the convex is fixed to the furnace wall and the furnace top using silicon nitride ceramic screws. The tightening torque of the silicon nitride ceramic screws is controlled at 5-10 N·m, and the bending strength of the silicon nitride ceramic screws is ≥600 MPa.

[0022] On the other hand, a construction method for the aforementioned convex structure that improves the radiation area and emissivity of a kiln is provided, comprising the following steps:

[0023] Step 1, Material preparation: Mix the raw materials according to the formula, and then pre-calcine the raw materials at high temperature after planetary ball milling, so that CaO / Fe2O3 preferentially forms calcium iron aluminate liquid phase to encapsulate ZrO2 particles and inhibit crystal transformation.

[0024] Step 2, Protrusion Forming: The material prepared in Step 1 is crushed to 150-250 mesh and formed into a protrusion by isostatic pressing;

[0025] Step 3, High-temperature sintering: The protrusion formed in step 2 is sintered, and the sintered protrusion is then surface polished.

[0026] Step 4, Modular Installation: Install the protrusions in the mortises of the furnace wall and furnace top, fix the protrusions with silicon nitride ceramic screws, and then fill the screw holes with aluminum dihydrogen phosphate-based high-temperature sealant.

[0027] Furthermore, in the above construction method, in step 1, the planetary ball milling time is 12h-24h, the ball-to-material ratio is 3:1, the pre-firing temperature is 1200℃-1400℃, and the pre-firing time is 2h-4h; in step 2, the hydraulic pressure for isostatic pressing is 200MPa-300MPa, and the dimensional error of the formed protrusion is ≤±2mm.

[0028] Furthermore, in the above construction method, in step 1 and step 3, the protrusion is sintered in an air atmosphere at 1600℃-1700℃, with a heating rate of 5℃ / min-10℃ / min.

[0029] Analysis reveals that this invention discloses a convex structure and its construction method for improving the radiation area and emissivity of a kiln. By setting convex structures on the furnace wall and roof, the radiation area is effectively increased, the emissivity is improved, the radiation shielding effect is eliminated, the uniformity of the thermal field inside the furnace is ensured, and energy consumption is reduced. The convex structures are constructed using modular methods, simplifying the installation process, reducing on-site adjustment costs, and improving construction stability. Attached Figure Description

[0030] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein:

[0031] Figure 1 This is a schematic diagram of the structure of the protrusions arranged on the furnace wall according to an embodiment of the present invention.

[0032] Figure 2 for Figure 1 A schematic diagram of the left-side view structure.

[0033] Figure 3 This is a flowchart of a construction method according to an embodiment of the present invention.

[0034] Explanation of reference numerals in the attached drawings: 1. Protrusion; 2. Furnace wall; 3. Silicon nitride ceramic screw. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation and not by way of limitation. Indeed, those skilled in the art will recognize that modifications and variations can be made to the invention without departing from its scope or spirit. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the invention encompass such modifications and variations falling within the scope of the appended claims and their equivalents.

[0036] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected," "linked," and "set up" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a direct connection or an indirect connection through intermediate components; a wired connection, a radio connection, or a wireless communication signal connection. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0037] The accompanying drawings illustrate one or more examples of the invention. The detailed description uses numerals and letters to refer to features in the drawings. Similar or analogous reference numerals in the drawings and description have been used to refer to similar or analogous parts of the invention. As used herein, the terms “first,” “second,” and “third,” etc., are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of individual components.

[0038] like Figures 1 to 3 As shown, according to an embodiment of the present invention, a convex structure for improving the radiation area and emissivity of a kiln is provided. The kiln includes a furnace wall 2 and a furnace roof. The convex structure includes a plurality of convexities 1, such as... Figure 1 As shown, several protrusions 1 cover the inner surface of the furnace wall 2 and the inner surface of the furnace top. The protrusions 1 are pyramidal, and the bottom of the protrusions 1 are connected to the furnace wall 2 or the furnace top.

[0039] The design specifications of the protrusion 1 need to consider factors such as balancing radiation area gain and space utilization. If the size is too small, the increase in radiation area will be limited; if it is too large, it may cause the protrusions 1 to block each other and increase the load on the furnace wall 2. In one embodiment of the present invention, the protrusion 1 is a regular triangular pyramid with a base side length of 100mm-200mm (e.g., 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, 200mm) and a height of 50mm-100mm (e.g., 50mm, 60mm, 70mm, 80mm, 90mm, 100mm). The angle between the side of the regular triangular pyramid and the surface of the furnace wall 2 or the furnace roof is 60°. In another embodiment of the present invention, the protrusion 1 is a regular square pyramid with a base side length of 100mm-200mm (e.g., 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, 200mm), a height of 80mm-150mm (e.g., 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm), and a apex angle of the side face of the regular square pyramid of 90°-120° (e.g., 90°, 100°, 110°, 120°). The convex body 1, with its multi-sided pyramidal structure, increases the kiln's radiant area by 30%-50% compared to the flat furnace wall 2, significantly improving heat radiation efficiency. The size range of the convex body 1 is suitable for the internal space of most industrial kilns, balancing practicality and energy efficiency. If the design angle of the convex body 1 is too small, the side inclination will be too large, causing heat to easily reflect into the furnace wall 2; if the angle is too large, it will approach a flat surface, resulting in insufficient radiant area gain. Therefore, the convex body 1 uses a 60° included angle (when the convex body 1 is a regular triangular pyramid) or a 90°-120° apex angle (when the convex body 1 is a regular square pyramid), which allows the radiation direction of the convex body 1's sides to be more evenly directed towards the heating area inside the furnace, avoiding heat concentration or scattering and ensuring a uniform heat field distribution within the kiln.

[0040] Furthermore, on the walls and top of the furnace wall 2, the protrusions 1 are arranged in an equilateral triangle pattern, with the distance between the center points of the bases of two adjacent protrusions 1 being 1.0-1.5 times the height of the protrusion 1. This arrangement eliminates the radiation shading effect. If the spacing between the protrusions 1 is too small, the sides of adjacent protrusions 1 will block each other's radiation paths; if it is too large, it will waste space in the furnace wall 2 and reduce the radiation density. The equilateral triangle arrangement is the most compact, unobstructed layout. Combined with the design of "spacing = 1.0-1.5 times the height," it ensures that the side radiation of each protrusion 1 can effectively cover the area inside the furnace, avoiding shadow areas, maximizing radiation utilization, reducing energy reflection loss, and indirectly enhancing radiation efficiency.

[0041] Furthermore, the material of protrusion 1 is a LaAlO3-based composite material, and the chemical composition of protrusion 1 is: 70-85wt% LaAlO3, 5-10wt% CaO, 3-8wt% Fe2O3, and 5-15wt% Y2O3-stabilized ZrO2. These parameters meet the requirements of protrusion 1 for high-temperature stability and high emissivity. LaAlO3 serves as the high-temperature resistant matrix, while CaO and Fe2O3 form a calcium iron aluminate liquid phase, which encapsulates the ZrO2 particles to suppress their high-temperature crystal transformation (ZrO2 crystal transformation leads to abrupt volume change, causing material cracking). The Y2O3-stabilized ZrO2 enhances the high-temperature strength of protrusion 1, ensuring its long-term stable operation at 1600℃. The liquid-phase encapsulation structure also avoids the risk of cracking at high temperatures, extending its service life.

[0042] Since the main radiation band of industrial kilns is 0.76-2.5μm (visible to near-infrared), a high emissivity is required to match this band; the coefficient of thermal expansion must also match the matrix of the furnace wall 2 to avoid detachment due to expansion differences at high temperatures. The LaAlO3-based composite material used in the protrusion 1 of this invention has an average emissivity ≥0.95 in the 0.76-2.5μm band and a coefficient of thermal expansion of 6.5-7.5×10⁻⁶. -6 / ℃. Compared to traditional refractory materials (the emissivity of traditional refractory materials is mostly below 0.8), the emissivity of the protrusion 1 with the above chemical composition is increased by more than 18.75%, which greatly improves the radiation efficiency; the coefficient of thermal expansion is close to that of the furnace wall 2, which reduces thermal stress and ensures structural stability.

[0043] Furthermore, such as Figure 2As shown, the bottom end of the protrusion 1 is embedded in a mortise in the furnace wall 2 or the furnace roof. Since the protrusion 1, furnace wall 2, and furnace roof will expand at high temperatures, expansion space needs to be reserved. The embedding depth of the protrusion 1 must ensure connection strength to prevent it from falling off. In one embodiment of the invention, the depth to which the protrusion 1 is embedded in the furnace wall 2 and furnace roof is 1 / 3 to 1 / 2 of the height of the protrusion 1, and the fit clearance between the bottom end of the protrusion 1 and the mortise is 0.5mm to 1.0mm. This arrangement ensures that the protrusion 1 is stably installed on the furnace wall 2 and furnace roof, and the fit clearance between the protrusion 1 and the mortise can accommodate the high-temperature expansion of the protrusion 1, preventing compression deformation or cracking, and ensuring long-term stable operation of the kiln. Because metal screws are prone to oxidation and failure in the high-temperature environment of the kiln (≥1600℃), the tightening torque needs to be controlled to avoid overtightening that could cause the protrusion 1 or screw to break. In one embodiment of the present invention, the protrusion 1 is fixed to the furnace wall 2 or furnace top using silicon nitride ceramic screws 3 (M6-M10). The tightening torque of the silicon nitride ceramic screws 3 is controlled at 5-10 N·m, and the bending strength of the silicon nitride ceramic screws 3 is ≥600 MPa. The silicon nitride ceramic screws 3 have high temperature resistance and oxidation resistance, and the bending strength ≥600 MPa ensures load-bearing capacity; the torque control at 5-10 N·m balances fixing strength and structural safety, avoiding mechanical damage.

[0044] This invention increases the radiation area of ​​the kiln by 30-50% by setting protrusions 1 on the furnace wall 2 and the furnace top. The protrusions 1, which are made of LaAlO3-based composite material, can make the emissivity of the kiln ≥0.95. The two work together to make the thermal field inside the furnace uniform, with a maximum temperature difference ≤50℃ and energy consumption reduced by 15%-25%.

[0045] This invention also discloses a construction method for the above-mentioned convex structure for improving the radiation area and emissivity of a kiln, such as... Figure 3 As shown, it includes the following steps:

[0046] Step 1, Material Preparation: Mix the raw materials according to the specified ratio. After planetary ball milling, pre-calcine at high temperature to allow CaO / Fe2O3 to preferentially form a calcium iron aluminate liquid phase that encapsulates ZrO2 particles, inhibiting crystal transformation. The planetary ball milling time is 12-24 hours (e.g., 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h, 24h), the ball-to-material ratio is 3:1, the pre-calcine temperature is 1200℃-1400℃ (e.g., 1200℃, 1250℃, 1300℃, 1350℃, 1400℃), and the pre-calcine time is 2-4 hours (e.g., 2h, 2.5h, 3h, 3.5h, 4h). The above ball milling parameters ensure uniform mixing and fine particle size of the raw materials to guarantee compositional consistency. Planetary ball mills, through high-intensity grinding, can thoroughly mix raw materials such as LaAlO3, CaO, Fe2O3, and Y2O3-stabilized ZrO2. A grinding time of 12-24 hours ensures that the raw material particles achieve a uniform degree of fineness (laying the foundation for subsequent pulverization to 150-250 mesh), avoiding component segregation. The 3:1 ball-to-material ratio design allows for sufficient impact and grinding of the raw materials by the grinding media (balls), improving pulverization efficiency and ensuring uniform particle size, thus providing a prerequisite for the uniform reaction of each component during subsequent high-temperature pre-calcination. The pre-calcination temperature and time settings can complete the liquid-phase encapsulation reaction in advance, inhibiting the ZrO2 crystal transformation.

[0047] Step 2, Protrusion Forming: The material prepared in Step 1 is crushed to 150-250 mesh and protrusion 1 is formed by isostatic pressing. The hydraulic pressure for isostatic pressing is 200MPa-300MPa (e.g., 200MPa, 210MPa, 220MPa, 230MPa, 240MPa, 250MPa, 260MPa, 270MPa, 280MPa, 290MPa, 300MPa). The dimensional error of protrusion 1 is ≤ ±2mm.

[0048] Isostatic pressing (IPC) transfers uniform pressure to the green body through a liquid medium. Insufficient IPC pressure leads to low density and insufficient strength in protrusion 1; excessively rapid heating can easily cause internal stress cracking in protrusion 1. A pressure range of 200MPa-300MPa ensures that the LaAlO3-based composite material particles are fully compacted, reducing internal porosity. This pressure range ensures that the protrusion 1 green body achieves high density (laying the foundation for high strength and low permeability after subsequent high-temperature sintering) while avoiding excessive pressure that could lead to excessive breakage of raw material particles or cracking of the green body, thus balancing molding efficiency and material integrity. Ultimately, this results in sintered protrusion 1 possessing sufficient structural strength to withstand the thermal stress and mechanical impact under the high-temperature environment of the kiln.

[0049] Controlling the dimensional error of protrusion 1 ensures its installation accuracy and avoids problems such as being too loose (insecure fixation) or too tight (cracking under pressure during high-temperature expansion) due to dimensional deviations. It also ensures uniform spacing between adjacent protrusions 1, eliminating radiation obstruction effects caused by dimensional deviations and maximizing the utilization of the radiation area. Uniform dimensional accuracy simplifies the installation process, reduces on-site adjustment costs, and improves construction stability.

[0050] Step 3, High-Temperature Sintering: The protrusion 1 formed in Step 2 is sintered, and the sintered protrusion 1 is then surface-polished. Protrusion 1 is sintered in an air atmosphere at 1600℃-1700℃ (e.g., 1600℃, 1610℃, 1620℃, 1630℃, 1640℃, 1650℃, 1660℃, 1670℃, 1680℃, 1690℃, 1700℃) at a heating rate of 5℃ / min-10℃ / min (e.g., 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min). This setting ensures complete material densification, improving the strength and high-temperature resistance of protrusion 1. The sintering of protrusion 1 in an air atmosphere at 1600℃-1700℃ matches the characteristics of the protrusion 1 material (LaAlO3-based composite material), ensuring sufficient material densification. This temperature range also promotes the full reaction and diffusion of components such as the LaAlO3 matrix, the calcium iron aluminate liquid phase formed by CaO / Fe2O3, and the Y2O3-stabilized ZrO2 particles, forming a uniform and stable microstructure. This improves the material's density and high-temperature strength, providing a foundation for the stability (e.g., thermal shock resistance and creep resistance) of protrusion 1 during long-term operation in a furnace at 1600℃. During sintering of protrusion 1, if the temperature rises too quickly, uneven heating in different areas of the material can easily lead to cracks due to differences in thermal expansion. Using a heating rate of 5℃ / min-10℃ / min avoids thermal stress caused by excessive temperature gradients within protrusion 1, ensuring a uniform temperature rise, reducing internal stress accumulation, maintaining structural integrity during sintering, and preventing cracking. When LaAlO3-based composite materials are sintered in an air atmosphere, the chemical stability of each component (such as LaAlO3 and Y2O3-stabilized ZrO2) is good, and compositional degradation does not occur due to oxidation or other reactions. Using an air atmosphere simplifies the process, reduces costs, and simultaneously meets the material sintering requirements.

[0051] Step 4, Modular Installation: Install the protrusion 1 in the mortises of the furnace wall 2 and the furnace top, fix the protrusion 1 with silicon nitride ceramic screws 3, and then fill the joint between the protrusion 1 and the furnace wall 2 with aluminum dihydrogen phosphate-based high-temperature sealant.

[0052] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0053] A protruding structure and its construction method for improving the radiation area and emissivity of a kiln are disclosed. By setting protrusions 1 on the wall surface 2 and the top of the kiln, the radiation area is effectively increased, the emissivity is improved, the radiation blocking effect is eliminated, the heat field inside the kiln is ensured to be uniform, and energy consumption is reduced. The protrusions 1 are constructed using modular construction, which simplifies the installation process, reduces on-site adjustment costs, and improves construction stability.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A convex structure for improving the radiation area and emissivity of a kiln, the kiln comprising a furnace wall and a furnace roof, characterized in that, Includes several convex bodies. Several of the aforementioned protrusions cover the inner surface of the furnace wall and the inner surface of the furnace roof. The protrusion is a pyramid. The bottom end of the protrusion is connected to the furnace wall or the furnace top.

2. The convex structure for improving the radiation area and emissivity of a kiln according to claim 1, characterized in that, The convex body is a regular triangular pyramid, and the side length of the base of the regular triangular pyramid is 100mm-200mm. The height of the regular triangular pyramid is 50mm-100mm. The angle between the side of the regular triangular pyramid and the wall surface of the furnace wall or the surface of the furnace top is 60°.

3. The convex structure for improving the radiation area and emissivity of a kiln according to claim 1, characterized in that, The convex body is a regular square pyramid, and the side length of the base of the regular square pyramid is 100mm-200mm. The height of the regular square pyramid is 80mm-150mm. The vertex angle of the side face of the regular square pyramid is 90°-120°.

4. The convex structure for improving the radiation area and emissivity of a kiln according to claim 1, characterized in that, On the furnace wall and the furnace top, the protrusions are laid out in an equilateral triangle pattern, and the distance between the center points of the bottom surfaces of two adjacent protrusions is 1.0-1.5 times the height of the protrusion.

5. The convex structure for improving the radiation area and emissivity of a kiln according to claim 1, characterized in that, The protrusion is made of LaAlO3-based composite material. The chemical composition of the protrusion is: LaAlO3 70-85wt%, CaO 5-10wt%, Fe2O3 3-8wt%, Y2O3-stabilized ZrO 25-15wt%. LaAlO3-based composite materials exhibit an average emissivity ≥0.95 in the 0.76–2.5 μm wavelength range and a coefficient of thermal expansion of 6.5–7.5 × 10⁻⁶. -6 / ℃.

6. The convex structure for improving the radiation area and emissivity of a kiln according to claim 1, characterized in that, The bottom end of the protrusion is embedded in a mortise in the furnace wall or the furnace roof, and the depth to which the protrusion is embedded in the furnace wall and the furnace roof is 1 / 3 to 1 / 2 of the height of the protrusion. The gap between the bottom end of the protrusion and the mortise is 0.5mm-1.0mm.

7. The convex structure for improving the radiation area and emissivity of a kiln according to claim 1, characterized in that, The protrusion is fixed to the furnace wall and the furnace top with silicon nitride ceramic screws. The tightening torque of the silicon nitride ceramic screws is controlled at 5-10 N·m, and the bending strength of the silicon nitride ceramic screws is ≥600 MPa.

8. A construction method for a convex structure for improving the radiation area and emissivity of a kiln as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1, Material preparation: Mix the raw materials according to the formula, and then pre-calcine the raw materials at high temperature after planetary ball milling, so that CaO / Fe2O3 preferentially forms calcium iron aluminate liquid phase to encapsulate ZrO2 particles and inhibit crystal transformation. Step 2, Protrusion Forming: The material prepared in Step 1 is crushed to 150-250 mesh and formed into a protrusion by isostatic pressing; Step 3, High-temperature sintering: The protrusion formed in step 2 is sintered, and the sintered protrusion is then surface polished. Step 4, Modular Installation: Install the protrusions in the mortises of the furnace wall and furnace top, fix the protrusions with silicon nitride ceramic screws, and then fill the screw holes with aluminum dihydrogen phosphate-based high-temperature sealant.

9. The construction method according to claim 8, characterized in that, In step 1, the planetary ball milling time is 12h-24h, the ball-to-material ratio is 3:1, the pre-firing temperature is 1200℃-1400℃, and the pre-firing time is 2h-4h. In step 2, the hydraulic pressure for isostatic pressing is 200MPa-300MPa, and the dimensional error of the formed protrusion is ≤±2mm.

10. The construction method according to claim 8, characterized in that, In step 3, the protrusion is sintered in an air atmosphere at 1600℃-1700℃, with a heating rate of 5℃ / min-10℃ / min.

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