Double water pipe column heat insulation structure of heating furnace for high temperature oriented silicon steel and preparation method thereof

Abstract

This invention discloses a heat insulation structure for a double-water-pipe column of a high-temperature oriented silicon steel heating furnace, comprising a precast layer of calcium hexaluminate refractory material, a thermal expansion and fastening compensation layer, a refractory fiber blanket layer, a nanoporous heat insulation board layer, and double water-cooled steel pipes. The preparation method includes compacting and fixing the nanoporous heat insulation board layer and the refractory fiber blanket layer using a heat insulation layer compaction and fixing mold before constructing the precast layer of calcium hexaluminate refractory material. This invention improves resistance to molten ferrous silicate erosion and heat insulation performance through the use of precast calcium hexaluminate working lining. It enhances the column's heat insulation performance and high-temperature performance by using multi-layer heat insulation materials with different temperature ranges. The combined design of mortise and tenon structure and thermal expansion self-locking structure eliminates anchors and metal fixing blocks, solving problems such as material thermal expansion mismatch, stress concentration damage, and heat island effect. It has advantages such as excellent heat insulation performance, resistance to molten ferrous silicate erosion, and short construction time.

Description

Technical Field

[0001] This invention relates to the field of energy-saving technology for heating furnaces, specifically to a double-water-pipe column heat insulation structure suitable for heating furnaces used in high-temperature oriented silicon steel and its preparation method. Background Technology

[0002] As a crucial piece of equipment for heating steel billets, the heating furnace's heating capacity, production efficiency, and energy consumption level are of great significance to the large-scale, low-cost production of the entire hot rolling production line. During the heating process of high-temperature oriented silicon steel, the high furnace temperature and long furnace time lead to significant oxidation and burn-off of the steel billet within the furnace. Furthermore, the oxidation of Fe and Si elements on the billet surface forms molten ferrous silicate, which continuously flows onto the water beams and columns supporting the billet and onto the furnace bottom. This molten slag comes into contact with, erodes, and adheres to the refractory materials of the water beams and columns, forming a large amount of suspended slag. This not only accelerates the damage to the insulation lining of the water beams and columns but also worsens the combustion conditions in the lower space of the heating furnace. Ultimately, the furnace must be shut down for slag removal because it cannot meet the heating quality requirements of the steel billet and normal production operation, resulting in decreased furnace production efficiency, increased shutdown maintenance costs, and increased furnace fuel consumption. Therefore, reducing the erosion of the water beams and columns by molten ferrous silicate, reducing slag buildup, improving insulation performance, and enabling rapid replacement of the insulation lining are particularly important for the low-energy-consumption and high-efficiency production of high-temperature oriented silicon steel heating furnaces.

[0003] In existing technologies, traditional water beam and column insulation structures mostly employ a double-layer composite structure. The inner layer is a 20mm thick refractory fiber blanket, and the outer layer is a 60mm thick silicon-aluminum self-flowing castable. This structure has poor thermal shock stability, with a service life typically of only 2-3 years. Sometimes, localized repairs are required after a very short period. Furthermore, the self-flowing castable has a high thermal conductivity (1.2W / m·K, hot surface temperature 1000℃) and poor insulation performance, which is one of the main reasons for the high water-cooling heat loss in water beams and columns. In addition, the performance of the self-flowing castable in water beams and columns is greatly affected by construction factors, and the curing and baking time is long, often affecting production due to extended maintenance cycles. Moreover, the silicon-aluminum self-flowing castable has poor resistance to ferrous silicate corrosion, making it difficult to meet the requirements of high-efficiency heating of high-temperature oriented silicon steel. Some companies have tried to replace the two-layer composite structure composed of castable and ceramic fiber blanket with a single ceramic fiber module. This structure reduced the heat carried away by cooling water by 38%. However, the module made of Al2O3-SiO2 ceramic fiber has low strength and cannot resist the corrosion of iron oxide scale. It requires furnace shutdown for maintenance and repair every six months and has not been promoted and applied in actual production.

[0004] Patent CN103388055B discloses a refractory insulation lining structure for the furnace beams and columns of a walking beam furnace for heating high-temperature oriented silicon steel. The structure includes metal pipes forming the foundation of the furnace beams or columns. Heat-resistant pads are spaced along the axial direction on the metal pipes forming the foundation. Metal anchors are evenly distributed along the axial and circumferential directions on the outer wall of the metal pipes. A refractory insulation layer, integrated with the metal anchors, is cast tightly against the outer wall of the metal pipes. An anti-slag adhesion layer and an anti-oxidation coating are then sequentially applied to the outside of the refractory insulation layer. This invention's refractory insulation lining for the furnace beams and columns of the walking beam furnace employs a double-layer structure of insulation and anti-slag adhesion layers with appropriate thicknesses, enhancing the overall integrity of the insulation lining and improving its comprehensive performance, thus meeting the requirements for heat insulation and slag erosion prevention for the water beams and columns of high-temperature oriented silicon steel furnaces. However, this patent still cannot solve the problems of long construction cycles, large fluctuations in construction quality, and cracking and damage caused by the anchor + castable construction method, which are inherent to the anchor + castable construction method.

[0005] The invention patent with publication number CN105444579A discloses a method for wrapping the water beam of a heating furnace. A fixing block is set on the outer surface of the water pipe at the bottom of the furnace. Precast blocks A and B are made of insulating material with a thermal conductivity of less than 1.0 W / m·K and are made into semi-cylindrical precast blocks. Precast blocks A and B are fitted together to form a cylinder and have grooves of the same size as the fixing block inside. Precast blocks A and B are installed on the outside of the water pipe at the bottom of the furnace and their internal grooves are tightly connected to the fixing block. Finally, the connection between precast blocks A and B and the connection between precast blocks A and B and the water pipe at the bottom of the furnace are sealed with high-temperature mortar. This patent uses metal fixing blocks welded onto water-cooled steel pipes to fix precast blocks A and B. Due to the large difference in thermal expansion coefficients between metal and insulation materials, cracks are easily generated at the corners of the joint due to stress concentration, leading to damage. In addition, insulation materials with a thermal conductivity of less than 1.0 W / m·K have a relatively high thermal conductivity and insufficient thermal insulation performance. Furthermore, the metal fixing blocks are larger in volume than conventional anchors, resulting in a more significant heat island effect and accelerating local heat transfer.

[0006] Utility model CN216745396U discloses a novel insulation component for the water beam column of a walking beam steel rolling furnace, comprising multiple insulation bodies, each with a mortise and tenon structure. Adjacent insulation bodies are connected end-to-end via the mortise and tenon structure, forming an annular insulation layer wrapped around the water beam column (lower half of the furnace bottom). This utility model's insulation component is assembled from insulation bodies with mortise and tenon structures, replacing traditional clamping with mortise and tenon joints. The mortise and tenon interlocking method, using arc-shaped tenons and mortises, improves installation convenience while strengthening the connection of the insulation body under high-temperature conditions. To ensure the dimensional accuracy of the mortise and tenon structure, it is laser-cut to guarantee manufacturing precision. Simultaneously, the insulation body uses a novel nanoporous aerogel insulation material, effectively improving the insulation performance of the component. The application scenario of this utility model is that the water beam column of the heating furnace is located in the lower half of the furnace bottom. It can only be used as a heat preservation component for sealing and heat preservation at the junction of the furnace bottom and the column. It cannot be used in the high-temperature area inside the furnace of the water beam column of the heating furnace. The main reason is that the new nanoporous aerogel insulation material has disadvantages such as low strength and low operating temperature. The maximum operating temperature of SiO2 nanoporous aerogel insulation material is generally below 800℃, and its resistance to iron oxide scale and ferrous silicate corrosion and its resistance to high-temperature flue gas erosion are poor. It cannot meet the performance requirements for long-term use in the high-temperature flue gas of 900-1300℃ in the steel rolling heating furnace.

[0007] Utility model patent CN216282703U discloses a heat-insulating and energy-saving structure for a heating furnace water beam. From the cold side to the hot side, the structure consists of a flexible nanoplate, a ceramic fiber blanket, and a castable refractory. The flexible nanoplate and ceramic fiber blanket are sewn together with stitching, and the castable refractory is fixed with Y-shaped anchors. Double-sided adhesive can be applied to the surface of the flexible nanoplate. This heat-insulating and energy-saving structure for the heating furnace water beam can perfectly cover the water beam wall panel, ensuring service life and performance. It effectively solves the problem of temporary water repellency and can be temporarily adhered to the water beam wall panel, reducing construction difficulty. It also has an extremely low thermal conductivity, effectively reducing heat loss. However, this patent cannot solve the problems of long construction cycles, large fluctuations in construction quality, and cracking and damage caused by the anchor + castable refractory construction method.

[0008] In summary, the existing traditional water beam and column insulation structures, which employ a double-layer composite structure of refractory fiber blanket and silicon-aluminum self-flowing castable, suffer from problems such as long construction time, large fluctuations in construction quality, poor insulation performance and resistance to ferrous silicate erosion, and short service life. Although some patents have proposed a double-layer structure of insulation layer and anti-slag layer for refractory insulation lining, reducing high-temperature slag adhesion, most of the aforementioned problems remain unresolved. In addition, some invention patents have explored prefabricated insulation methods, but these still suffer from insufficient high-temperature performance and insulation performance, difficulty in resisting ferrous silicate molten erosion, thermal expansion mismatch between insulation components, and stress concentration leading to easy damage. Therefore, it is necessary to further research a double-water-pipe column insulation structure suitable for high-temperature oriented silicon steel heating furnaces, aiming to achieve comprehensive goals such as improving column insulation and resistance to ferrous silicate molten erosion, reducing furnace energy consumption, extending the service life of column insulation lining, and shortening construction time, while ensuring its high-temperature performance. Summary of the Invention

[0009] To overcome the shortcomings of the above-mentioned technologies, the present invention provides a double-water-pipe column heat insulation structure for a high-temperature oriented silicon steel heating furnace and its preparation method, which can achieve comprehensive goals such as improving the heat insulation performance and resistance to molten ferrous silicate corrosion of the column, reducing the energy consumption of the heating furnace, extending the service life of the column heat insulation structure, and shortening the construction time.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A double-water-pipe column insulation structure for a high-temperature grain-oriented silicon steel heating furnace is disclosed. This structure forms the furnace column connecting the furnace bottom and the crossbeam insulation lining. The furnace column includes two water-cooled steel pipes connected by flat steel. The outer surfaces of the double-water-cooled steel pipes are sequentially covered from the inside out with a nanoporous insulation board layer, a refractory fiber blanket layer, a thermal expansion compensation layer, and a prefabricated layer of calcium hexaluminate refractory material. The main chemical composition and mass percentage of the prefabricated layer of calcium hexaluminate refractory material are: Al₂O₃ 88-92%, CaO 7-11%, SiO₂ <1.5%, Fe₂O₃ <1.0%, with the balance being unavoidable impurities. The performance indicators of the prefabricated layer of calcium hexaluminate refractory material are: density 1.9-2.5 g / cm³. 3 The compressive strength at room temperature (1300℃×3h) is ≥35MPa, and the thermal conductivity is ≤0.55W / m·K (hot surface temperature 800℃); the main crystalline phase in the precast layer of the calcium hexaaluminate refractory material is CaAl. 12 O 19 And the content is ≥80wt%.

[0012] Preferably, the calcium hexaaluminate refractory prefabricated layer is formed by sequentially splicing and stacking a set of bottom elliptical ring prefabricated parts and multiple sets of upper elliptical ring prefabricated parts with mortise and tenon joints.

[0013] Preferably, the bottom elliptical ring prefabricated component is formed by mortise and tenon joints of two first prefabricated components and two second prefabricated components;

[0014] The first precast component is a semi-circular structure with a flat bottom that contacts the bottom of the heating furnace. A first arc-shaped tenon is provided in the middle of the top, and a first long strip tenon and a first long strip mortise are provided in the middle of both ends, respectively.

[0015] The second precast component has a flat side and a protrusion on the other side that matches the concave surface in the middle of the double water-cooled steel pipe. Its bottom is flat and contacts the bottom of the heating furnace. A first tenon is provided in the middle of the top, and a second long tenon and a second long mortise are provided in the middle of both ends, respectively.

[0016] The bottom elliptical ring prefabricated component can be formed by sequentially mortising and tenoning together one of the first prefabricated components, one of the second prefabricated components, another of the first prefabricated components, and another of the second prefabricated components.

[0017] Preferably, the upper elliptical ring prefabricated component is formed by mortise and tenon joints of two third prefabricated components and two fourth prefabricated components.

[0018] The third prefabricated component is a semi-circular structure with an arc-shaped mortise at the middle of its bottom, a second arc-shaped tenon at the middle of its top, and a third elongated tenon and a third elongated mortise at the middle of its two ends, respectively.

[0019] The fourth prefabricated component has a flat side and a protruding side that matches the concave surface in the middle of the double water-cooled steel pipe. A first mortise is provided at the middle position of its bottom, a second tenon is provided at the middle position of its top, and a fourth elongated tenon and a fourth elongated mortise are provided at the middle positions of both ends, respectively.

[0020] The upper elliptical ring prefabricated component can be formed by sequentially mortising and tenoning together one of the third prefabricated components, one of the fourth prefabricated components, another of the third prefabricated components, and another of the fourth prefabricated components.

[0021] Preferably, the bottom elliptical ring precast component is joined to the adjacent upper elliptical ring precast component by means of its first arc-shaped tenon and first tenon respectively fitting with the arc-shaped mortise and first mortise of the adjacent upper elliptical ring precast component; the upper elliptical ring precast component is joined to the adjacent upper elliptical ring precast component by means of its bottom arc-shaped mortise and first mortise respectively fitting with the second arc-shaped tenon and second tenon of the adjacent upper elliptical ring precast component.

[0022] Preferably, the thermal expansion fastening compensation layer is formed by the thermal expansion coating itself growing under heat expansion; the thermal expansion coating is applied to the inner side of the calcium hexaaluminate refractory preform layer, and comprises the following components by mass percentage: 25-40% self-crosslinking acrylic emulsion, 10-20% ammonium polyphosphate (degree of polymerization ≥1000), 2-5% dipentaerythritol, 5-10% melamine, 15-30% calcium hexaaluminate ultrafine powder (particle size ≤10μm), and 15-25% deionized water.

[0023] Preferably, the refractory fiber blanket layer is formed by wrapping and splicing single-layer refractory fiber blankets, and Z-shaped right-angle steps are set at the splicing positions at both ends.

[0024] Preferably, the nanoporous heat insulation plate layer is composed of two continuous double semi-annular columnar nanoporous heat insulation plates spliced ​​together, with Z-shaped right-angle steps set at both ends of the splicing position.

[0025] A method for preparing a heat insulation structure for a double-water-pipe column of a high-temperature oriented silicon steel heating furnace is characterized by the following steps: after wrapping a nanoporous heat insulation board layer and a refractory fiber blanket layer, the refractory fiber blanket layer is compacted and fixed using a heat insulation layer compaction and fixing mold before the construction of a calcium hexaaluminate refractory material precast layer. After each layer of calcium hexaaluminate refractory material precast layer is completed, the heat insulation layer compaction and fixing mold is moved upwards. The heat insulation layer compaction and fixing mold is composed of two symmetrical mold components hinged together, and its outer contour is consistent with the cross-sectional shape of the double water-cooled steel pipe. It can be opened from one side and locked with a button after closing.

[0026] Preferably, the procedure specifically includes the following steps:

[0027] 1) Apply a thermal expansion coating to the inside of all the first, second, third and fourth preforms. When heated during operation, it will form a thermal expansion and fastening compensation layer. After application, allow it to air dry at room temperature.

[0028] 2) Clean the surface of the double water-cooled steel pipes that serve as the foundation for the heating furnace columns;

[0029] 3) Wrap a layer of nanoporous heat insulation board with Z-shaped right-angle steps at both ends around the double water-cooled steel pipe, and fix it with plastic film to form a nanoporous heat insulation board layer.

[0030] 4) Wrap a layer of refractory fiber blanket with Z-shaped right-angle steps at both ends around the nanoporous insulation board layer to form a refractory fiber blanket layer. Open the insulation layer compaction and fixing mold, wrap and compact the refractory fiber blanket layer, and lock it with a button to control the compression of the refractory fiber blanket to 10-20%.

[0031] 5) Install two second prefabricated pieces with thermal expansion coating on the inner side into the recess in the middle of the double water-cooled steel pipe wrapped with nanoporous heat insulation board layer and refractory fiber blanket layer and place them at the bottom of the double water-cooled steel pipe. Then, mortise and tenon splice a first prefabricated piece with thermal expansion coating on the inner side from the left and right sides respectively to form a bottom elliptical ring prefabricated piece, which contacts the bottom of the heating furnace. Pull the insulation layer compaction and fixing mold upward and move it to the outer wall of the next section of refractory fiber blanket layer.

[0032] 6) Take two fourth precast pieces with thermal expansion coating on the inner side and place them in the recess between the double water-cooled steel pipes wrapped with nanoporous heat insulation board and refractory fiber blanket. Place them on the bottom elliptical ring precast piece. Then, mortise and tenon splice a third precast piece with thermal expansion coating on the inner side from the left and right sides respectively to form an upper elliptical ring precast piece. Then, mortise and tenon splice the upper and lower parts of the upper elliptical ring precast piece and install it on the top of the bottom elliptical ring precast piece. Press the insulation layer and fix the mold upward and move it to the outer wall of the next section of refractory fiber blanket.

[0033] 7) Take two more fourth prefabricated pieces with thermal expansion coating on the inner side and place them in the recess between the double water-cooled steel pipes wrapped with nanoporous heat insulation board and refractory fiber blanket. Place them on the previous upper elliptical ring prefabricated piece. Splice a third prefabricated piece with thermal expansion coating on the inner side from the left and right sides to form another upper elliptical ring prefabricated piece. Then, install the upper elliptical ring prefabricated piece on the top of the previous upper elliptical ring prefabricated piece with mortise and tenon joints. Pull out the insulation layer compaction and fixing mold and move it to the outer wall of the next section of refractory fiber blanket.

[0034] 8) Repeat step 7) and continue to install the upper elliptical ring precast component. After setting a 3-5mm expansion joint at about half the height of the double water-cooled steel pipe, continue to repeat step 7) and build to the top of the double water-cooled steel pipe. Remove the insulation layer and compact the mold to complete the production of the heating furnace column.

[0035] 9) After curing for 12 hours, the construction of the crossbeam insulation lining connected to the top of the heating furnace column was completed according to the double insulation lining method of refractory fiber blanket + self-flowing castable, thus forming the overall water beam and column insulation structure of the heating furnace.

[0036] The contact surfaces of the mortise and tenon joints and the stacked joints are bonded and sealed with high-temperature refractory mortar.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] This invention provides a double-water-pipe column insulation structure for a high-temperature oriented silicon steel heating furnace, which can be used not only in conventional hot rolling furnaces but is also particularly suitable for high-temperature oriented silicon steel heating furnaces. This invention improves resistance to molten ferrous silicate erosion and insulation performance through the use of precast calcium hexaaluminate working linings. Optimized settings using multi-layer insulation materials with different temperature ranges enhance the column's insulation and high-temperature performance. The combined design of mortise and tenon joints and a thermally expanding self-locking structure eliminates anchors and metal fixing blocks, solving problems such as material thermal expansion mismatch, stress concentration damage, and heat island effect. It offers advantages such as excellent insulation performance, resistance to molten ferrous silicate erosion, and short construction time.

[0039] By selecting calcium hexaaluminate refractory as the working layer of the column, compared with the Al2O3-SiO2 self-flowing castable used in conventional water beams, the CaO-Al2O3 refractory does not contain SiO2, which can avoid the reaction of iron oxide scale with SiO2 to form a low-melting phase. Utilizing the excellent resistance of calcium hexaaluminate to ferrous silicate corrosion, the problem of corrosion of the column by the large amount of molten ferrous silicate generated during the production of high-temperature oriented silicon steel is solved. At the same time, the low thermal conductivity of calcium hexaaluminate refractory, which decreases slightly with increasing temperature, and the interwoven hexagonal plate-like microporous structure within the material, are fully utilized to improve the thermal insulation performance under high-temperature operating conditions.

[0040] By employing a combined design of mortise and tenon joints, refractory mortar bonding and sealing, and a self-locking structure of thermal expansion compensation layer for the prefabricated calcium hexaluminate refractory material layer, this technology replaces the existing method of casting and curing refractory materials. This eliminates the need for metal anchors and metal fixing blocks, resolving issues such as material thermal expansion mismatch, stress concentration damage, and heat island effect. Furthermore, it eliminates the need for a series of construction processes including refractory formwork, casting, curing, and furnace drying, significantly shortening the fabrication and construction time of the heating furnace column insulation lining, reducing the number of days of furnace shutdown for maintenance, and improving production efficiency.

[0041] Based on the different operating temperatures of different areas of the insulation layer, a double-layer design of refractory fiber blanket and nanoporous insulation board is optimized to further improve the thermal insulation performance of the column. The high temperature resistance and low thermal conductivity of the refractory fiber blanket are fully utilized as a transition insulation layer for the prefabricated components adjacent to the hot surface working layer. When the operating temperature drops to below 500℃, the ultra-low thermal conductivity of the nanoporous insulation board is utilized to ensure that it operates within the optimal performance operating temperature range. This ensures that the nanoporous insulation board maintains excellent thermal insulation performance during long-term use and effectively prevents performance degradation.

[0042] The Z-shaped right-angle step design at the joints of the refractory fiber blanket and the nanoporous insulation board avoids the problem of increased overlap area size affecting the external circular dimension deviation of the column insulation layer caused by conventional overlapping construction, while also reducing the impact of splicing gaps. Furthermore, the use of a compaction mold for the insulation layer to fix and compact the refractory fiber blanket solves the problem of difficulty in compacting and fixing irregularly shaped areas with double water pipes in the absence of anchors.

[0043] By designing a thermal expansion and fastening compensation layer, using calcium hexaaluminate ultrafine powder as filler and a combination of ammonium polyphosphate, dipentaerythritol, and melamine as a foaming expansion agent, the thermal expansion coating expands in volume when the temperature rises (≥300℃) to form a porous calcium hexaaluminate thermal expansion and fastening compensation layer. This layer has a low thermal conductivity and can fill the gap between the hot-surface prefabricated parts and the insulation layer, further compacting the refractory fiber blanket and improving the overall performance, insulation performance, and service life of the multi-layer thermal insulation lining structure of the heating furnace column.

[0044] This invention uses only four types of prefabricated components to assemble the calcium hexaaluminate refractory prefabricated component layer in the double-water-pipe column heat insulation structure of a high-temperature oriented silicon steel heating furnace. Among them, prefabricated component one and prefabricated component three can be directly used for assembling the calcium hexaaluminate refractory prefabricated component layer in the single-water-pipe column heat insulation structure. When it is necessary to prepare both single-water-pipe and double-water-pipe column heat insulation structures at the same time, the types of prefabricated components are reduced, the mold manufacturing cost is reduced, the warehouse storage management is simplified, and the overall production cost is reduced. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of a double-water-pipe column heat insulation structure for a heating furnace used in high-temperature oriented silicon steel, as described in a specific embodiment of the present invention.

[0046] Figure 2 for Figure 1 A schematic diagram of the AA section of the bottom elliptical ring precast component.

[0047] Figure 3 for Figure 2 Schematic diagram of the CC section.

[0048] Figure 4 for Figure 1 Schematic diagram of the BB section of the upper and middle elliptical ring prefabricated component.

[0049] Figure 5 for Figure 4 Schematic diagram of the DD section.

[0050] Figure 6 for Figure 2 A three-dimensional structural schematic diagram of the first prefabricated component.

[0051] Figure 7 , Figure 8 for Figure 2 A three-dimensional structural schematic diagram of the second prefabricated component.

[0052] Figure 9 for Figure 4 A three-dimensional structural schematic diagram of the third prefabricated component.

[0053] Figure 10 for Figure 9 The front view of the third precast component.

[0054] Figure 11 for Figure 10 Top view of the third precast component.

[0055] Figure 12 , Figure 13 for Figure 4 A three-dimensional structural schematic diagram of the fourth prefabricated component.

[0056] Figure 14 for Figure 12 Top view of the fourth precast component.

[0057] Figure 15 A schematic diagram showing the opening / closing state of the mold for compacting and fixing the insulation layer.

[0058] Figure reference numerals: 1 layer of calcium hexaaluminate refractory precast material (including: bottom elliptical ring precast 1.1, upper elliptical ring precast 1.2), 2 thermal expansion fastening compensation layer, 3 refractory fiber blanket layer, 4 nano-microporous heat insulation board layer, 5 double water-cooled steel pipe, 6 furnace bottom of heating furnace, 7 heat insulation layer compaction and fixing mold, 8 heating furnace column, 9 crossbeam heat insulation lining;

[0059] The bottom elliptical ring prefabricated part 1.1 includes a first prefabricated part 1.11 (wherein, a first arc-shaped tenon 1.11a, a first elongated tenon 1.11b, and a first elongated mortise 1.11c) and a second prefabricated part 1.12 (wherein, a first tenon 1.12a, a second elongated mortise 1.12b, and a second elongated tenon 1.12c);

[0060] The upper elliptical ring prefabricated component 1.2 includes a third prefabricated component 1.21 (of which, an arc-shaped mortise 1.21a, a second arc-shaped tenon 1.21b, a third elongated tenon 1.21c, and a third elongated mortise 1.21d) and a fourth prefabricated component 1.22 (of which, a first mortise 1.22a, a second tenon 1.22b, a fourth elongated mortise 1.22c, and a fourth elongated tenon 1.22d). Detailed Implementation

[0061] To better explain the present invention, the main contents of the present invention are further illustrated below with reference to specific embodiments, but the contents of the present invention are not limited to the following embodiments.

[0062] like Figure 1-14 As shown, this invention designs a double-water-pipe column insulation structure for a high-temperature oriented silicon steel heating furnace. It forms a furnace column 8 connecting the furnace bottom 6 and the crossbeam insulation lining 9. The furnace column 8 includes double water-cooled steel pipes 5, each composed of two water-cooled steel pipes connected by flat steel. The outer sides of the double water-cooled steel pipes 5 are sequentially covered from the inside out with a nanoporous insulation board layer 4, a refractory fiber blanket layer 3, a thermal expansion fastening compensation layer 2, and a calcium hexaaluminate refractory prefabricated component layer 1. The overall insulation structure does not use metal anchors or fixing blocks. The main chemical composition and mass percentage of the calcium hexaaluminate refractory prefabricated component layer 1 are: Al2O3 88-92%, CaO 7-11%, SiO2 <1.5%, Fe2O3 <1.0%, with the balance being unavoidable impurities. The performance indicators of the calcium hexaaluminate refractory prefabricated component layer 1 are as follows: density 1.9-2.5 g / cm³. 3 The compressive strength at room temperature (1300℃×3h) is ≥35MPa, and the thermal conductivity is ≤0.55W / m·K (hot surface temperature 800℃); the main crystalline phase in layer 1 of the calcium hexaaluminate refractory precast component is CaAl. 12 O 19 And the content is ≥80wt%.

[0063] The calcium hexaluminate refractory precast layer 1 is constructed by sequentially splicing and stacking a set of bottom elliptical ring precast parts 1.1 and multiple sets of upper elliptical ring precast parts 1.2 with mortise and tenon joints. The bottom elliptical ring precast parts 1.1 and the upper elliptical ring precast parts 1.2 are both 60-300mm high and 50-80mm thick.

[0064] The bottom elliptical ring precast component 1.1 is assembled from two first precast components 1.11 and two second precast components 1.12 using mortise and tenon joints. The first precast component 1.11 has a semi-circular structure with a flat bottom that contacts the furnace bottom 6. A first arc-shaped tenon 1.11a is provided at the middle of the top, and a first elongated tenon 1.11b and a first elongated mortise 1.11c are provided at the middle of both ends, respectively. The second precast component 1.12 has a flat side on one side and a protrusion on the other side that matches the concave surface in the middle of the double water-cooled steel pipe 5. The bottom is flat and contacts the furnace bottom 6. A first tenon 1.12a is provided at the middle of the top, and a second elongated tenon 1.12c and a second elongated mortise 1.12b are provided at the middle of both ends, respectively.

[0065] The bottom elliptical ring prefabricated component 1.1 is formed by mortise and tenon joints of one first prefabricated component 1.11, one second prefabricated component 1.12, another first prefabricated component 1.11, and another second prefabricated component 1.12.

[0066] The upper elliptical ring precast component 1.2 is assembled by mortise and tenon joints of two third precast components 1.21 and two fourth precast components 1.22. The third precast component 1.21 has a semi-circular structure with an arc-shaped mortise 1.21a at the middle of the bottom, a second arc-shaped tenon 1.21b at the middle of the top, and a third elongated tenon 1.21c and a third elongated mortise 1.21d at the middle of each end. The fourth precast component 1.22 has a flat side on one side and a protrusion on the other side that matches the concave surface in the middle of the double water-cooled steel pipe 5. It has a first mortise 1.22a at the middle of the bottom, a second tenon 1.22b at the middle of the top, and a fourth elongated tenon 1.22d and a fourth elongated mortise 1.22c at the middle of each end.

[0067] The upper elliptical ring prefabricated component 1.2 is formed by mortise and tenon joints of one third prefabricated component 1.21, one fourth prefabricated component 1.22, another third prefabricated component 1.21, and another fourth prefabricated component 1.22.

[0068] The bottom elliptical ring prefabricated component 1.1 is joined to the adjacent upper elliptical ring prefabricated component 1.2 by its first arc-shaped tenon 1.11a and first tenon 1.12a, respectively, with the arc-shaped mortise 1.21a and first mortise 1.22a. The upper elliptical ring prefabricated component 1.2 is joined to the adjacent upper elliptical ring prefabricated component 1.2 by its bottom arc-shaped mortise 1.21a and first mortise 1.22a, respectively, with the second arc-shaped tenon 1.21b and second tenon 1.22b.

[0069] All the tenons and mortises have semi-circular cross-sections, and the diameter of the semi-circular cross-section of each tenon is 2-5mm smaller than the diameter of the semi-circular cross-section of the mortis it fits with.

[0070] All contact surfaces of the mortise and tenon joints and stacking are bonded and sealed with high-temperature refractory mortar; the high-temperature refractory mortar is an air-hardening refractory mortar with a maximum service temperature (under oxidizing atmosphere) ≥1500℃; the high-temperature refractory mortar is TJM air-hardening refractory mortar produced by Morgan Thermal Ceramics Co., Ltd.

[0071] The thermal expansion fastening compensation layer 2 has a thickness of 3-5mm and is formed by the thermal expansion coating itself growing under thermal expansion at temperatures exceeding 300℃. The thermal expansion coating is applied to the inner side of the calcium hexaaluminate refractory precast layer 1, with a thickness of 0.2-1mm, and includes the following components by mass percentage: 25-40% self-crosslinking acrylic emulsion, 10-20% ammonium polyphosphate (degree of polymerization ≥1000), 2-5% dipentaerythritol, 5-10% melamine, 15-30% ultrafine calcium hexaaluminate powder (particle size ≤10μm), and 15-25% deionized water.

[0072] The refractory fiber blanket layer 3 is 20-35mm thick and is composed of single-layer refractory fiber blankets wrapped and spliced ​​together. Z-shaped right-angle steps are provided at both ends of the splicing to reduce the impact of the splicing gaps. The material performance indicators of the refractory fiber blanket are: density 160kg / m³. 3 The operating temperature is ≥1100℃, the slag ball content is ≤10%, and the thermal conductivity is ≤0.18W / m·K (hot surface temperature 800℃). The refractory fiber blanket is one of the following: high alumina aluminosilicate refractory fiber blanket, zirconium-containing aluminosilicate refractory fiber blanket, or alkaline earth metal refractory fiber blanket.

[0073] The nanoporous insulation layer 4 is 5-10mm thick and is composed of two continuous, double-semi-annular columnar nanoporous insulation panels spliced ​​together. Z-shaped right-angle steps are provided at both ends of the splice to reduce the impact of the splice gap. The material performance indicators of the nanoporous insulation panel are: density ≤ 0.45g / cm³. 3 Thermal conductivity ≤0.05W / m·K (hot surface temperature 800℃), room temperature compressive strength ≥0.4MPa, shrinkage rate ≤0.4% (1000℃×24h).

[0074] The preparation method of the above-mentioned high-temperature oriented silicon steel heating furnace double water pipe column heat insulation structure includes, after wrapping the nanoporous heat insulation board layer 4 and the refractory fiber blanket layer 3, using the heat insulation layer compaction and fixing mold 7 to compact and fix the refractory fiber blanket layer 3, and then constructing the calcium hexaaluminate refractory material precast layer 1. After the construction and masonry of each layer of calcium hexaaluminate refractory material precast component is completed, the heat insulation layer compaction and fixing mold 7 is moved upward by one section; the heat insulation layer compaction and fixing mold 7 is composed of two symmetrical mold components hinged together, and its outer contour is consistent with the cross-sectional shape of the double water-cooled steel pipe 5, such as Figure 15 As shown, the insulation layer compaction and fixing mold 7 is made of PVC material with a thickness of 1-2mm. It can be opened from one side and locked with a button after closing.

[0075] The above preparation method specifically includes the following steps:

[0076] 1) Apply a thermal expansion coating to the inner side of all first preforms 1.11, second preforms 1.12, third preforms 1.21 and fourth preforms 1.22. When heated during operation, the coating will form a thermal expansion and fastening compensation layer 2. After coating, air dry at room temperature for ≥12 hours.

[0077] 2) Use a steel brush to clean the surface of the double water-cooled steel pipe 5, which serves as the foundation for the heating furnace column 8, of floating dust and rust;

[0078] 3) Wrap a layer of nanoporous heat insulation board with Z-shaped right-angle steps at both ends of the double water-cooled steel pipe 5 around the outside, and use plastic film to wrap and fix it to form nanoporous heat insulation board layer 4.

[0079] 4) Wrap a layer of refractory fiber blanket with Z-shaped right-angle steps at both ends around the nanoporous insulation board layer 4 to form refractory fiber blanket layer 3. Open the insulation layer compaction and fixing mold 7 to wrap and compact the refractory fiber blanket layer 3, and lock it with a button to control the compression of the refractory fiber blanket to 10-20%.

[0080] 5) Apply high-temperature refractory mortar to the bottom, top, and both ends of the two first precast pieces 1.11 with inner sides coated with thermal expansion coating and the two second precast pieces 1.12 with inner sides coated with thermal expansion coating. First, install the two second precast pieces 1.12 in the recess between the double water-cooled steel pipes 5 wrapped with nanoporous heat insulation board layer 4 and refractory fiber blanket layer 3 and place them at the furnace bottom 6 of the heating furnace. Then, mortise and tenon joint one of the first precast pieces 1.11 from the left and right sides respectively. Among them, the second long strip tenon 1.12 of one of the second precast pieces 1.12 c and the second elongated mortise 1.12b are respectively joined with the first elongated mortise 1.11c of one first precast part 1.11 and the first elongated tenon 1.11b of another first precast part 1.11, forming a bottom elliptical ring precast part 1.1 by combining two first precast parts 1.11 and two second precast parts 1.12. The bottom elliptical ring precast part 1.1 is then brought into contact with the furnace bottom 6 of the heating furnace. The insulation layer is then bonded and sealed with high-temperature refractory mortar. The insulation layer is then compacted and fixed by the mold 7, which is pulled upward and moved to the outer wall of the next section of refractory fiber blanket layer 3.

[0081] 6) Apply high-temperature refractory mortar to the top and both ends of the two third precast pieces 1.21 with inner sides coated with thermal expansion coating and the two fourth precast pieces 1.22 with inner sides coated with thermal expansion coating. First, place the two fourth precast pieces 1.22 in the recess between the double water-cooled steel pipes 5 wrapped with nanoporous heat insulation board layer 4 and refractory fiber blanket layer 3, and place them on the bottom elliptical ring precast piece 1.1. Then, mortise and tenon join one third precast piece 1.21 from the left and right sides respectively. Among them, the fourth long strip tenon 1.22d and the fourth long strip tenon of one fourth precast piece 1.22 The groove 1.22c is respectively joined with the third long strip mortise 1.21d of a third precast part 1.21 and the third long strip tenon 1.21c of another third precast part 1.21. The two third precast parts 1.21 and the two fourth precast parts 1.22 are combined to form an upper elliptical ring precast part 1.2. The upper elliptical ring precast part 1.2 is then installed on the top of the bottom elliptical ring precast part 1.1 with the upper and lower mortise and tenon joints. The insulation layer is then bonded and sealed with high-temperature refractory mortar. The insulation layer is then pressed and fixed. The mold 7 is pulled upward and moved to the outer wall of the next section of refractory fiber blanket layer 3.

[0082] 7) Continue to apply high-temperature refractory mortar to the top and both ends of the two third precast pieces 1.21 with the inner side coated with thermal expansion coating and the two fourth precast pieces 1.22 with the inner side coated with thermal expansion coating. First, place the two fourth precast pieces 1.22 in the recess between the double water-cooled steel pipes 5 wrapped with nanoporous heat insulation board layer 4 and refractory fiber blanket layer 3, and place them on the upper elliptical ring precast piece 1.2. Then, mortise and tenon assemble one third precast piece 1.21 from the left and right sides respectively. Among them, the fourth long strip tenon 1.22d and the fourth long strip tenon of one fourth precast piece 1.22 are joined together. The groove 1.22c is respectively joined with the third long strip mortise 1.21d of a third precast part 1.21 and the third long strip tenon 1.21c of another third precast part 1.21. The two third precast parts 1.21 and the two fourth precast parts 1.22 are combined to form another upper elliptical ring precast part 1.2. The upper and lower elliptical ring precast part 1.2 is then installed on the top of the previous upper elliptical ring precast part 1.2 with mortise and tenon joints. The insulation layer is then pressed and sealed with high-temperature refractory mortar. The mold 7 is pulled upward and moved to the outer wall of the next section of refractory fiber blanket layer 3.

[0083] 8) Repeat step 7) and continue to install the upper elliptical ring precast component 1.2. After building to about half the height of the double water-cooled steel pipe 5, use ceramic fiber paper to set a 3-5mm expansion joint and continue to repeat step 7) until the top of the double water-cooled steel pipe 5 is built. Remove the insulation layer and compact the mold 7 to complete the production of the heating furnace column 8.

[0084] 9) After curing for 12 hours, the construction of the crossbeam insulation lining 9 connected to the top of the heating furnace column 8 is completed according to the conventional method of making double insulation lining of refractory fiber blanket + self-flowing castable. Finally, the construction of the overall water beam and column insulation lining of the heating furnace is completed.

[0085] The following are several heat insulation structures for double water pipe columns of high-temperature grain-oriented silicon steel heating furnaces, with slight differences in size and material:

[0086] Example 1

[0087] The specific parameters of the dimensions and materials of each component in this embodiment are as follows:

[0088] The outer diameter of each water-cooled steel pipe that makes up the double water-cooled steel pipe 5 is 140mm and the height is 1800mm.

[0089] The bottom elliptical ring precast component 1.1 and the upper elliptical ring precast component 1.2, which make up the calcium aluminate hexahydrate refractory precast component layer 1, are both 76 mm high and 60 mm thick. The semicircular diameters of the cross-sections of each tenon and mortise are 17 mm and 20 mm, respectively.

[0090] The precast calcium hexaluminate refractory materials mainly consist of the following chemical composition by mass percentage: Al2O3: 89.54%, CaO: 8.27%, SiO2: 0.94%, Fe2O3: 0.60%, with the balance being unavoidable impurities. Its main performance indicators are: room temperature compressive strength (1300℃×3h) 35.6MPa, thermal conductivity 0.35W / m·K (hot surface temperature 800℃), and density 1.98g / cm³. 3 The main crystalline phase in the precast calcium hexaaluminate refractory material is CaAl. 12 O 19 The content is 82.3 wt%.

[0091] The high-temperature refractory mortar is TJM air-hardening refractory mortar produced by Morgan Thermal Ceramics Co., Ltd., with a maximum service temperature (under oxidizing atmosphere) ≥1500℃.

[0092] The thickness of the thermal expansion fastening compensation layer 2 is 3 mm. The thickness of the thermal expansion coating is 0.5 mm, and its components and mass percentage content are as follows: 30% self-crosslinking acrylic emulsion, 15% ammonium polyphosphate (degree of polymerization ≥1000), 4% dipentaerythritol, 6% melamine, 30% calcium hexaaluminate ultrafine powder (particle size ≤10μm), and 15% deionized water.

[0093] The refractory fiber blanket layer 3 is 20mm thick, composed of 25mm thick refractory fiber blankets wrapped, compacted, and spliced ​​together. The refractory fiber blankets are Alkali Earth Metal Refractory Fiber Blankets—Super Cotton Prime Blankets—manufactured by Morgan Thermo-Ceramics Co., Ltd., with a density of 160kg / m³. 3 It has an operating temperature of 1150℃, a slag ball content of ≤5%, and a thermal conductivity of 0.18W / m·K (hot surface temperature 800℃). It has the advantages of low thermal conductivity, environmental friendliness, and non-carcinogenicity.

[0094] The thickness of layer 4 of the nanoporous insulation board is 5mm. The nanoporous insulation board uses WDS microporous insulation board manufactured by Morgan Thermo-Ceramics Co., Ltd., with a density of 0.36g / cm³. 3 Thermal conductivity 0.044 W / m·K (hot surface temperature 800℃), room temperature compressive strength 0.5 MPa, shrinkage rate 0.3% (1000℃×24h).

[0095] In the process of preparing the calcium hexaaluminate refractory precast layer 1, the height of the expansion joint is set to 3mm.

[0096] The thickness of the insulation layer compaction and fixing mold 7 is 1mm.

[0097] Example 2

[0098] The specific parameters of the dimensions and materials of each component in this embodiment are as follows:

[0099] The outer diameter of each water-cooled steel pipe that makes up the double water-cooled steel pipe 5 is 194mm and the height is 2000mm.

[0100] The bottom elliptical ring precast component 1.1 and the upper elliptical ring precast component 1.2, which make up the calcium aluminate hexahydrate refractory precast component layer 1, are both 150 mm high and 70 mm thick. The semicircular diameters of the cross-sections of each tenon and mortise are 17 mm and 20 mm, respectively.

[0101] The precast calcium hexaluminate refractory material comprises the following chemical composition by mass percentage: Al₂O₃: 88.2%, CaO: 10.5%, SiO₂: 0.42%, Fe₂O₃: 0.43%, with the balance being unavoidable impurities. The main performance indicators of the precast calcium hexaluminate refractory material are: room temperature compressive strength (1300℃×3h) 59.7MPa, thermal conductivity 0.44W / m·K (hot surface temperature 800℃), and density 2.32g / cm³. 3 The main crystalline phase in the precast calcium hexaaluminate refractory material is CaAl. 12 O 19 The content is 84.6 wt%.

[0102] The high-temperature refractory mortar is TJM air-hardening refractory mortar produced by Morgan Thermal Ceramics Co., Ltd., with a maximum service temperature (under oxidizing atmosphere) ≥1500℃.

[0103] The thickness of the thermal expansion fastening compensation layer 2 is 4 mm; the thickness of the thermal expansion coating is 0.6 mm, and its components and mass percentage content are as follows: 40% self-crosslinking acrylic emulsion, 10% ammonium polyphosphate (polymerization degree ≥1000), 2% dipentaerythritol, 5% melamine, 25% calcium hexaaluminate ultrafine powder (particle size ≤10μm), and 18% deionized water.

[0104] The refractory fiber blanket layer 3 is 35mm thick and is composed of 40mm thick refractory fiber blankets wrapped, compacted, and spliced ​​together; the refractory fiber blanket is a high-alumina aluminosilicate fiber blanket with a density of 160kg / m³. 3 Operating temperature 1200℃, slag ball content ≤10%, thermal conductivity 0.16W / m·K (hot surface temperature 800℃).

[0105] The thickness of the nanoporous insulation layer 4 is 8mm; the nanoporous insulation board uses WDS microporous insulation board manufactured by Morgan Thermo-Ceramics Co., Ltd., with a density of 0.36g / cm³. 3 Thermal conductivity 0.044 W / m·K (hot surface temperature 800℃), room temperature compressive strength 0.5 MPa, shrinkage rate 0.3% (1000℃×24h).

[0106] In the process of preparing the calcium hexaaluminate refractory precast layer 1, the height of the expansion joint is set to 4 mm.

[0107] The thickness of the insulation layer compaction and fixing mold 7 is 2mm.

[0108] Example 3

[0109] The specific parameters of the dimensions and materials of each component in this embodiment are as follows:

[0110] The outer diameter of each water-cooled steel pipe that makes up the double water-cooled steel pipe 5 is 194mm and the height is 2150mm.

[0111] The bottom elliptical ring precast component 1.1 and the upper elliptical ring precast component 1.2, which make up the calcium hexaluminate refractory precast component layer 1, have a height of 300 mm and a thickness of 80 mm. The semicircular diameters of the cross-sections of each tenon and mortise are 20 mm and 25 mm, respectively.

[0112] The precast calcium hexaluminate refractory material comprises the following chemical composition by mass percentage: Al₂O₃: 91.6%, CaO: 7.2%, SiO₂: 0.45%, Fe₂O₃: 0.52%, with the balance being unavoidable impurities. The main performance indicators of the precast calcium hexaluminate refractory material are: room temperature compressive strength (1300℃×3h) 83.7MPa, thermal conductivity 0.54W / m·K (hot surface temperature 800℃), and density 2.49g / cm³. 3 The main crystalline phase in the precast calcium hexaaluminate refractory material is CaAl. 12 O 19 The content is 80.5 wt%.

[0113] The high-temperature refractory mortar is TJM air-hardening refractory mortar produced by Morgan Thermal Ceramics Co., Ltd., with a maximum service temperature (under oxidizing atmosphere) ≥1500℃.

[0114] The thickness of the thermal expansion fastening compensation layer 2 is 5 mm. The thickness of the thermal expansion coating is 0.8 mm, and its components and mass percentage content are as follows: 25% self-crosslinking acrylic emulsion, 20% ammonium polyphosphate (degree of polymerization ≥1000), 5% dipentaerythritol, 10% melamine, 15% calcium hexaaluminate ultrafine powder (particle size ≤10μm), and 25% deionized water.

[0115] The refractory fiber blanket layer 3 is 30mm thick, composed of 35mm thick refractory fiber blankets wrapped, compacted, and spliced ​​together. The refractory fiber blanket is a zirconium-aluminosilicate fiber blanket with a density of 160kg / m³. 3 Operating temperature 1350℃, slag ball content ≤10%, thermal conductivity 0.16W / m·K (hot surface temperature 800℃).

[0116] The fourth layer of the nanoporous insulation board is 10mm thick. The nanoporous insulation board uses a new type of high-strength nanoporous insulation board produced by Zhengzhou Jingwei Composite Materials Co., Ltd., with a density of 0.45g / cm³. 3Thermal conductivity 0.042 W / m·K (hot surface temperature 800℃), room temperature compressive strength 1.3 MPa, shrinkage rate 0.4% (1000℃×24h).

[0117] In the process of preparing the calcium hexaaluminate refractory precast layer 1, the height of the expansion joint is set to 5 mm.

[0118] The thickness of the insulation layer compaction and fixing mold 7 is 1.5mm.

[0119] All other unspecified parts belong to the prior art.

Claims

1. A double-water-pipe column insulation structure for a high-temperature oriented silicon steel heating furnace, comprising a heating furnace column (8) connected between the furnace bottom (6) and the crossbeam insulation lining (9), the heating furnace column (8) including double water-cooled steel pipes (5), the double water-cooled steel pipes (5) being composed of two water-cooled steel pipes connected by flat steel, characterized in that: The double water-cooled steel pipe (5) is covered from the inside out with a nanoporous heat insulation board layer (4), a refractory fiber blanket layer (3), a thermal expansion fastening compensation layer (2), and a calcium hexaaluminate refractory material prefabricated layer (1); the main chemical composition and mass percentage of the calcium hexaaluminate refractory material prefabricated layer (1) are: Al2O3 88-92%, CaO 7-11%, SiO2<1.5%, Fe2O3<1.0%, with the remainder being unavoidable impurities; the performance index of the calcium hexaaluminate refractory material prefabricated layer (1) is: density 1.9-2.5 g / cm³. 3 The room temperature compressive strength is ≥35MPa, and the thermal conductivity is ≤0.55W / m•K. The heat treatment conditions for the room temperature compressive strength test are 1300℃×3h, and the hot surface temperature for the thermal conductivity test is 800℃. The main crystalline phase in the calcium hexaaluminate refractory precast layer (1) is CaAl. 12 O 19 And the content is ≥80wt%.

2. The double-water-pipe column heat insulation structure for a high-temperature grain-oriented silicon steel heating furnace according to claim 1, characterized in that: The calcium hexaaluminate refractory precast layer (1) is formed by a set of bottom elliptical ring precast parts (1.1) and multiple sets of upper elliptical ring precast parts (1.2) sequentially spliced ​​and stacked with mortise and tenon joints.

3. The double-water-pipe column heat insulation structure for a high-temperature oriented silicon steel heating furnace according to claim 2, characterized in that: The bottom elliptical ring prefabricated component (1.1) is formed by mortise and tenon joints of two first prefabricated components (1.11) and two second prefabricated components (1.12); The first preform (1.11) is a semi-circular structure with a flat bottom that is in contact with the furnace bottom (6) of the heating furnace. A first arc-shaped tenon (1.11a) is provided at the middle position of the top, and a first long strip tenon (1.11b) and a first long strip mortise (1.11c) are provided at the middle positions of both ends respectively. The second precast component (1.12) has a flat side and a protrusion on the other side that matches the concave surface in the middle of the double water-cooled steel pipe (5). Its bottom is flat and contacts the furnace bottom (6) of the heating furnace. A first tenon (1.12a) is provided in the middle of the top, and a second long strip tenon (1.12c) and a second long strip mortise (1.12b) are provided in the middle of both ends respectively. The bottom elliptical ring precast part (1.1) can be formed by mortise and tenon jointing one of the first precast parts (1.11), one of the second precast parts (1.12), another of the first precast parts (1.11), and another of the second precast parts (1.12).

4. The double-water-pipe column heat insulation structure for a high-temperature oriented silicon steel heating furnace according to claim 2 or 3, characterized in that: The upper elliptical ring prefabricated component (1.2) is formed by mortise and tenon joints of two third prefabricated components (1.21) and two fourth prefabricated components (1.22); The third prefabricated component (1.21) is a semi-circular structure. An arc-shaped mortise (1.21a) is provided at the middle position of its bottom, a second arc-shaped tenon (1.21b) is provided at the middle position of its top, and a third elongated tenon (1.21c) and a third elongated mortise (1.21d) are provided at the middle positions of its two ends, respectively. The fourth precast component (1.22) has a flat side and a protrusion on the other side that matches the concave surface in the middle of the double water-cooled steel pipe (5). A first mortise (1.22a) is provided at the middle position of its bottom, a second tenon (1.22b) is provided at the middle position of its top, and a fourth long strip tenon (1.22d) and a fourth long strip mortise (1.22c) are provided at the middle positions of both ends, respectively. The upper elliptical ring prefabricated component (1.2) can be formed by sequentially mortising and tenoning together one of the third prefabricated components (1.21), one of the fourth prefabricated components (1.22), another of the third prefabricated components (1.21), and another of the fourth prefabricated components (1.22).

5. The double-water-pipe column heat insulation structure for a high-temperature oriented silicon steel heating furnace according to claim 4, characterized in that: The bottom elliptical ring prefabricated part (1.1) is joined with the adjacent upper elliptical ring prefabricated part (1.2) by its first arc tenon (1.11a) and first tenon (1.12a) respectively to the arc tenon (1.21a) and first tenon (1.22a) of its first arc tenon (1.11a) and first tenon (1.12a); the upper elliptical ring prefabricated part (1.2) is joined with the adjacent upper elliptical ring prefabricated part (1.2) by its second arc tenon (1.21b) and second tenon (1.22b) of its second arc tenon (1.21a) and first tenon (1.22a) of its first arc tenon (1.21a) and first tenon (1.22a) of its second arc tenon (1.21b) and second tenon (1.22b) of its second arc tenon (1.22a).

6. The double-water-pipe column heat insulation structure for a high-temperature oriented silicon steel heating furnace according to claim 1, characterized in that: The thermal expansion fastening compensation layer (2) is formed by the thermal expansion coating itself expanding under heat; the thermal expansion coating is applied to the inner side of the calcium hexaaluminate refractory preform layer (1), and includes the following components by mass percentage: 25-40% self-crosslinking acrylic emulsion, 10-20% ammonium polyphosphate with a degree of polymerization ≥1000, 2-5% dipentaerythritol, 5-10% melamine, 15-30% calcium hexaaluminate ultrafine powder with a particle size ≤10μm, and 15-25% deionized water.

7. The double-water-pipe column heat insulation structure for a high-temperature grain-oriented silicon steel heating furnace according to claim 1, characterized in that: The refractory fiber blanket layer (3) is made of a single layer of refractory fiber blanket wrapped and spliced ​​together, with Z-shaped right-angle steps set at both ends of the splicing position.

8. The double-water-pipe column heat insulation structure for a high-temperature grain-oriented silicon steel heating furnace according to claim 1, characterized in that: The nanoporous heat insulation plate layer (4) is composed of two continuous double semi-annular columnar nanoporous heat insulation plates spliced ​​together, with Z-shaped right-angle steps set at both ends of the splicing position.

9. A method for preparing the heat insulation structure of the double water pipe column for a high-temperature oriented silicon steel heating furnace as described in claim 5, characterized in that: After wrapping the nanoporous insulation board layer (4) and the refractory fiber blanket layer (3), the refractory fiber blanket layer (3) is compacted and fixed by the insulation layer compaction and fixing mold (7) before the construction of the calcium hexaaluminate refractory material prefabricated layer (1) is carried out. After the construction of each layer of calcium hexaaluminate refractory material prefabricated layer (1) is completed, the insulation layer compaction and fixing mold (7) is moved upward. The insulation layer compaction and fixing mold (7) is composed of two symmetrical mold parts hinged together. Its outer contour is consistent with the cross-sectional shape of the double water-cooled steel pipe (5). It can be opened from one side and locked by a button after closing.

10. The method for preparing the heat insulation structure of the double water pipe column for a high-temperature oriented silicon steel heating furnace according to claim 9, characterized in that: Specifically, the following steps are included: 1) Apply a thermal expansion coating to the inside of all the first preforms (1.11), the second preforms (1.12), the third preforms (1.21) and the fourth preforms (1.22). When heated during operation, the coating will form a thermal expansion and fastening compensation layer (2). After coating, air dry at room temperature. 2) Clean the surface of the double water-cooled steel pipe (5) that serves as the foundation for the heating furnace column (8); 3) Wrap a layer of nanoporous heat insulation board with Z-shaped right-angle steps at both ends of the double water-cooled steel pipe (5) and wrap it with plastic film to form a nanoporous heat insulation board layer (4). 4) Wrap a layer of refractory fiber blanket with Z-shaped right-angle steps at both ends around the nanoporous insulation board layer (4) to form a refractory fiber blanket layer (3). Open the insulation layer compaction and fixing mold (7) to wrap and compact the refractory fiber blanket layer (3) and lock it with a button to control the compression of the refractory fiber blanket to 10-20%. 5) Install two second preforms (1.12) with thermal expansion coating on the inner side in the recess of the double water-cooled steel pipe (5) which is wrapped with nanoporous heat insulation board layer (4) and refractory fiber blanket layer (3) and place them at the bottom of the double water-cooled steel pipe (5). Then, mortise and tenon splice a first preform (1.11) with thermal expansion coating on the inner side from the left and right sides respectively to form a bottom elliptical ring preform (1.1), which contacts the bottom of the heating furnace (6). Pull out the insulation layer compaction and fixing mold (7) upward and move it to the outer wall of the next section of refractory fiber blanket layer (3). 6) Take two pieces of the fourth preform (1.22) with the inner side coated with thermal expansion coating and place them in the recess of the double water-cooled steel pipe (5) wrapped with nanoporous heat insulation board layer (4) and refractory fiber blanket layer (3) and place them on the bottom elliptical ring preform (1.1). Then, mortise and tenon splice a piece of the third preform (1.21) with the inner side coated with thermal expansion coating from the left and right sides respectively to form an upper elliptical ring preform (1.2). Then, mortise and tenon splice the upper and lower elliptical ring preform (1.2) on the bottom elliptical ring preform (1.1). Pull out the insulation layer compaction and fixing mold (7) upward and move it to the outer wall of the next section of refractory fiber blanket layer (3). 7) Take two more fourth preforms (1.22) with thermal expansion coating on the inner side and place them in the recess of the double water-cooled steel pipe (5) wrapped with nanoporous heat insulation board layer (4) and refractory fiber blanket layer (3) and place them on the upper elliptical ring preform (1.2) in front. Then, mortise and tenon splice a third preform (1.21) with thermal expansion coating on the inner side from the left and right sides respectively to form another upper elliptical ring preform (1.2). Then, mortise and tenon splice the upper and lower parts of the upper elliptical ring preform (1.2) on the upper upper elliptical ring preform (1.2). Then, pull out the insulation layer compaction and fixing mold (7) upward and move it to the outer wall of the next section of refractory fiber blanket layer (3). 8) Repeat step 7) Continue to install the upper elliptical ring precast component (1.2). After building to half the height of the double water-cooled steel pipe (5), set a 3-5mm expansion joint and continue to repeat step 7) until the top of the double water-cooled steel pipe (5). Remove the insulation layer and compact the mold (7) to complete the production of the heating furnace column (8). 9) After curing for 12 hours, the construction of the crossbeam insulation lining (9) connected to the top of the heating furnace column (8) is completed according to the double insulation lining method of refractory fiber blanket + self-flowing castable, so as to finally form the overall water beam and column insulation structure of the heating furnace. The contact surfaces of the mortise and tenon joints and the stacked joints are bonded and sealed with high-temperature refractory mortar.

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