A multi-layer composite heat insulation structure for heating boiler water beam columns and a construction method thereof

Abstract

This invention relates to the field of thermal energy-saving technology for water beam systems at the bottom of heating furnaces, and particularly to a multi-layer composite insulation structure for water beam columns in heating furnaces. The structure includes anchor hooks staggered and fixed to the outer surface of the water pipes on the water beam columns, and insulation layers. From the inside out, the insulation layers consist of a first refractory insulation layer, a second refractory insulation layer, a metal mesh temperature-sensitive compensation layer, a castable working layer, a third refractory insulation layer, and metal-glass clamps fastened to the surface of the third refractory insulation layer. The third refractory insulation layer, fastened by the metal-glass clamps, has a sprayed coating working layer on its exterior. The anchor hooks are jointly covered by the first and second refractory insulation layers, the metal mesh temperature-sensitive compensation layer, and the castable working layer, with a thermal bridge blocking sleeve fitted at their ends. The material densities of the first and second refractory insulation layers and the thermal bridge blocking sleeve decrease in a gradient, forming a gradient density insulation structure. The insulation layer thickness of this invention approaches the critical thickness value, significantly reducing water-cooled heat loss.

Description

Technical Field

[0001] This invention belongs to the field of thermal energy-saving technology for water beam systems at the bottom of heating furnaces, and specifically relates to a multi-layer composite insulation structure for water beam columns in heating furnaces and its construction method. Background Technology

[0002] The water beams of the heating furnace are the core supporting equipment for the movement of steel billets within the furnace, and their service life directly affects the furnace's operating cycle. The cooling methods for the water beams are divided into water cooling and vaporization cooling. The furnace bottom water cooling system consists of horizontal beam water pipes and vertical column water pipes, with its water-cooled surface area accounting for approximately 40% to 50% of the total furnace bottom area. Water cooling heat loss carries away a significant amount of heat. Therefore, one of the key approaches to energy-saving retrofitting of the heating furnace is to reduce the heat loss of the furnace bottom water cooling system, requiring efficient thermal insulation wrapping of the outer surface of all water pipes.

[0003] Because the water beam crossbeam directly exerts radiation shielding and contact heat transfer effects on the steel billet, it easily leads to the formation and diffusion of the black mark temperature difference, affecting the heating quality of the steel billet. Therefore, it is not advisable to further increase the insulation layer thickness of the water beam crossbeam. The water beam columns and crossbeams are connected by tee fittings, maintaining a perpendicular relationship. There is a certain space between the upper end of the water pipe in the column and the lower surface of the steel billet, eliminating contact heat transfer. The degree of radiation shielding is also lower than that of the crossbeam, making it feasible to increase the insulation layer thickness. The research results show that when the insulation layer thickness of the water beam column is within the critical thickness range, the increase in insulation layer thickness has no significant effect on the black mark temperature difference of the steel billet.

[0004] In recent years, with the rapid development of nano-insulation material technology, new insulation media have been provided for water beam insulation structures, opening up new avenues for reducing water-cooled heat loss. For example, the patent CN216282703U heating furnace water beam insulation and energy-saving structure consists of a flexible nanoplate, a ceramic fiber blanket, and a castable refractory, arranged sequentially from the cold side to the hot side. 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. The advantages of this patent are: the structure can achieve complete coverage of the water beam wall panel, ensuring service life and insulation performance; it effectively solves the problem of temporary water repellency; it can be temporarily adhered to the water beam wall panel, reducing construction difficulty; and it has an extremely low thermal conductivity, helping to reduce heat loss. The shortcomings of this patent are as follows: First, the total thickness of the insulation structure is 80-100mm. Although it can achieve good insulation for the crossbeam water pipes, there is still potential to further increase the thickness of the column water pipes, meaning that there is room for optimization in the insulation efficiency of the existing technology in the column area. Second, to enhance the structural strength of the castable refractory, multiple Y-shaped anchors are welded to the outer wall of the water beam. Compared with nano-insulation boards, ceramic fiber blankets, and castable refractory, the Y-shaped anchors have a higher thermal conductivity and are densely arranged. The resulting thermal bridging effect will significantly affect the temperature distribution on the outer wall of the water beam and the heat dissipation behavior of the water pipes.

[0005] To reduce the thermal conductivity of anchors, existing technologies employ a method of covering the anchors with fiber "caps." This method increases local thermal resistance, reducing heat flux density and thus suppressing heat loss from the water beam. Patent CN202083229U describes a heating furnace water beam with an insulating cap, comprising anchor nails, a water beam, and castable refractory. One end of the anchor nail is fixed to the outer surface of the water beam, and the castable refractory is poured onto the outer surface of the water beam, encasing the anchor nail. Its key feature is the addition of a fiber-woven insulating sleeve and a ceramic fiber blanket. The insulating sleeve is fitted over the outer surface of the anchor nail, and the fiber blanket wraps around the outer surface of the water beam. The advantages of this patent are: convenient construction, long service life of the refractory material, and good energy-saving effect. The disadvantage of this patent is that its optimization measures focus on local insulation of the anchors but do not propose a systematic solution for the overall insulation structure of the water beam column. Significant room for improvement remains in suppressing the thermal bridging effect caused by the anchors.

[0006] Patent CN117760221A describes a thermal insulation structure for a single water pipe column of a high-temperature oriented silicon steel heating furnace and its preparation method. The structure includes a nanoporous thermal insulation board layer, a refractory fiber blanket layer, a thermal expansion and fastening compensation layer, and a precast layer of calcium hexaaluminate refractory material. The advantages of this patent are: improved resistance to molten ferrous silicate erosion and enhanced thermal insulation performance through the use of precast calcium hexaaluminate working lining; improved thermal insulation and high-temperature performance of the column through optimized use of multi-layer thermal insulation materials with different temperature ranges; and elimination of anchors and metal fixing blocks through a combined design of mortise and tenon structure and thermal expansion self-locking structure, thus solving problems such as material thermal expansion mismatch, stress concentration damage, and heat island effect. The patent offers excellent thermal insulation performance, resistance to molten ferrous silicate erosion, short construction time, and long service life. The shortcoming of this patent is that when a thermal expansion and fastening compensation layer replaces the traditional anchoring structure, the compensation layer contracts under conditions of rapid furnace temperature drop. This leads to a decrease in the interfacial bonding strength between the nanoporous insulation board layer, the refractory fiber blanket layer, and the refractory prefabricated component layer. Consequently, under the combined effects of high-temperature airflow and billet load within the furnace, large-scale spalling failure of the insulation layer occurs. Therefore, welding anchors to the wall of the water beam column to achieve mechanical anchoring of the wrapping material and enhance the thermal shock resistance and spalling resistance of the insulation layer remains a crucial and irreplaceable technical aspect of the water beam insulation structure.

[0007] Patent CN118564772A describes a high-heat-resistance composite wrapping structure for the water beam column of a steel rolling heating furnace, comprising, from the inside out, a new material insulation layer, a first alloy sheet, a ceramic fiber layer, a second alloy sheet, and a refractory layer. The advantages of this patent are: the selection scheme of various insulation materials is optimized according to the operating temperature of different areas of the insulation layer, giving this multi-layer composite wrapping structure high heat resistance. The disadvantages of this patent are: 1) One end of the first anchoring nail is welded to the outer wall of the water beam pipe, and the other end is welded to the first alloy sheet. This design causes the thermal bridge effect caused by the anchoring nail to expand from a discrete point thermal short circuit to a continuous planar thermal short circuit, significantly aggravating the overall heat dissipation loss of the water beam pipe; 2) The second anchoring nail and the second alloy sheet structurally form a relay conduction path for the heat flow from the first anchoring nail, resulting in additional heat loss.

[0008] In summary, the existing technology has the following shortcomings: 1) In terms of reducing water cooling heat loss, there is still potential to further increase the thickness of the insulation layer in the column water pipe area, that is, there is still room for improvement in the thermal insulation performance of the existing technology in this area; however, simply increasing the thickness of the insulation layer will inevitably increase the mechanical load of the water beam system, affecting its structural stability and normal operation.

[0009] 2) When the thermal expansion fastening compensation layer is used to replace the traditional anchoring structure, the compensation layer will shrink due to the cold under the condition of rapid furnace temperature drop, which will significantly reduce the bonding strength of the insulation layer interface. As a result, the insulation layer will peel off and fail on a large scale under the action of high temperature and high speed airflow in the furnace and dynamic load of steel billet.

[0010] 3) Regarding the synergistic optimization of anchor insulation performance and critical insulation layer thickness, existing technologies lack systematic optimization schemes for the insulation materials of the water beam column insulation layer and working layer. Furthermore, existing solutions are mostly limited to single-pipe column structures, lacking applicability to double-pipe columns and exhibiting significant limitations in application scope. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to provide a multi-layer composite insulation structure for water beam columns of heating furnaces and its construction method, which increases the thickness without increasing the total mass of the insulation layer, fully taps the energy-saving potential of the column area, and significantly reduces water cooling heat loss.

[0012] To achieve the above objectives, the present invention employs the following technical solution: A multi-layer composite thermal insulation structure for a water beam column of a heating furnace includes anchor hooks that are staggered and fixed to the outer surface of the water pipes of the water beam column and an insulation layer. The insulation layer consists of a first refractory insulation layer, a second refractory insulation layer, a metal mesh temperature-sensitive compensation layer, a castable working layer, a third refractory insulation layer, and a metal glass clamp fastened to the surface of the third refractory insulation layer. The third refractory insulation layer fastened by the metal glass clamp is provided with a spray coating working layer on the outside. The anchoring hook is covered by a first and a second refractory insulation layer, a metal mesh temperature-sensitive compensation layer and a castable working layer, and its end is fitted with a thermal bridge blocking sleeve; the material density of the first refractory insulation layer, the second refractory insulation layer and the thermal bridge blocking sleeve are distributed in a gradient decreasing distribution, forming a gradient density thermal insulation structure.

[0013] The thickness δ of the insulation layer 立柱 ≤critical thickness δ 临界 Critical thickness δ 临界 =Thickness of the insulation layer of the beam δ 横梁 +0.1× Distance L from the top of the water pipe of the water beam column to the bottom surface of the steel billet.

[0014] The first refractory insulation layer is bonded to the outer wall of the water pipe of the water beam column, the first refractory insulation layer is bonded to the second refractory insulation layer, and the castable working layer is bonded to the third refractory insulation layer with sodium silicate inorganic adhesive.

[0015] The first refractory insulation layer is composed of a nanoporous heat insulation board.

[0016] The second refractory insulation layer is composed of a nanoporous ceramic fiber composite material.

[0017] The thermal bridge blocking sleeve is composed of a ceramic fiber felt prefabricated component.

[0018] The temperature-sensitive compensation layer of the metal mesh is woven from shape memory alloy wires with a mesh spacing of 45-55mm.

[0019] The working layer of the castable is formed by casting a room-temperature curing castable, and its chemical composition by mass percentage is: Al2O3: 60%-80%, SiO2: 10%-25%, CaO: 1%-3%, Fe2O3≤1.5%, and other oxides≤2.0%.

[0020] The third refractory insulation layer is composed of annular heat-insulating fiber felt, and the composition of the heat-insulating fiber felt by mass percentage is: base material: 55%-60% alumina fiber, 35%-40% ceramic fiber, and accelerator: 3.5%-5.5% sodium fluorosilicate.

[0021] The metal-glass clamp is assembled from paired metal-glass rings through a closed structure.

[0022] The coating working layer is composed of a zirconium-containing ceramic fiber reinforced coating. The chemical composition of the zirconium-containing ceramic fiber reinforced coating by mass percentage is as follows: zirconium-containing ceramic fiber with ZrO2 ≥ 8%: 40%-60%; silicon carbide micro powder: 15%-20%; nano zirconium oxide: 5%; aluminum phosphate-silica sol composite liquid: 15%-20%; rare earth oxides: 3%; stainless steel fiber: 4%; defoamer: 1%.

[0023] A construction method for a multi-layer composite thermal insulation structure for water beam columns in a heating furnace includes the following steps: S1. Weld anchor hooks to the water pipes of the water beam column, with a spacing of 70-80mm, and an effective length of 60%-80% of the total thickness of the first and second refractory insulation layers and the castable working layer; S2. Coat the outer wall of the water pipe of the water beam column with sodium silicate inorganic binder and lay the first refractory insulation layer; S3. Apply sodium silicate inorganic binder to the outside of the first refractory insulation layer, and then lay the second refractory insulation layer; S4. After applying a 0.5-1.0mm thick layer of asphalt paint to the exposed section of the anchor hook, install the thermal bridge blocking sleeve; S5. Shape memory alloy wires are interlaced and wound on the rod of the anchor hook to form a mesh structure on the outer surface of the second refractory insulation layer, which is the metal mesh temperature-sensitive compensation layer. S6. Use steel molds to support the surface of the metal mesh temperature-sensitive compensation layer, pour the castable working layer with room temperature curing castable, vibrate it fully, and demold after room temperature curing. S7. Clean and trim the surface of the castable working layer, apply sodium silicate inorganic binder, and then lay the third refractory insulation layer; after confirming complete adhesion, use metal and glass clamps to fix the third refractory insulation layer at intervals on the outer surface; S8. Spray zirconium-containing ceramic fiber reinforced coating evenly onto the outer surface of the fixed third refractory insulation layer to form a spray coating working layer. After the spraying is completed, ignite the furnace according to the process specifications and then put it into operation.

[0024] Compared with existing technologies, the beneficial effects of this invention are: 1) The insulation layer thickness of this invention is close to the critical thickness value, which fully taps the energy-saving potential of the column area and significantly reduces water cooling heat loss; 2) Design a thermal bridge blocking sleeve with thermal bridge blocking function and a gradient density structure of refractory insulation layer. While maintaining the reliability of mechanical anchoring, it can suppress the thermal short circuit effect caused by anchors to the maximum extent and effectively reduce local heat loss. 3) The working layer of the castable uses room temperature curing castable combined with a metal mesh temperature-sensitive compensation layer, which avoids the cracking risk caused by traditional baking process and comprehensively extends the service life of refractory materials. 4) Low-density, high-performance insulation materials are used to increase the thickness without increasing the total mass of the insulation layer, thus avoiding additional mechanical loads on the water beam system.

[0025] 5) It has a castable working layer and a spray coating working layer, which makes it more impact resistant. Attached Figure Description

[0026] Figure 1 This is a structural diagram of Example 1.

[0027] Figure 2 This is a cross-sectional view of the structure of Example 1.

[0028] Figure 3 This is a structural diagram of Example 2.

[0029] Figure 4 This is a cross-sectional view of the structure in Example 2.

[0030] In the diagram: 1. Water pipe of water beam column; 2. Anchor hook; 3. First refractory insulation layer; 4. Second refractory insulation layer; 5. Thermal bridge blocking sleeve; 6. Castable working layer; 7. Third refractory insulation layer; 8. Metal glass clamp; 9. Spray paint working layer; 10. Metal mesh temperature-sensitive compensation layer. Detailed Implementation

[0031] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. The reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0032] A multi-layer composite thermal insulation structure for a water beam column of a heating furnace includes anchor hooks 2 that are staggered and fixed to the outer surface of the water pipe 1 of the water beam column and an insulation layer. The insulation layer consists of a first refractory insulation layer 3, a second refractory insulation layer 4, a metal mesh temperature-sensitive compensation layer 10, a castable working layer 6, a third refractory insulation layer 7, and a metal glass clamp 8 fastened to the surface of the third refractory insulation layer 7. The third refractory insulation layer fastened by the metal glass clamp 8 is provided with a spray coating working layer 9 on the outside. The anchor hook 2 is wrapped by the first and second refractory insulation layers (3, 4), the metal mesh temperature-sensitive compensation layer 10 and the castable working layer 6, and its end is fitted with a thermal bridge blocking sleeve 5; the material density of the first refractory insulation layer 3, the second refractory insulation layer 4 and the thermal bridge blocking sleeve 5 is distributed in a gradient decreasing distribution, forming a gradient density thermal insulation structure.

[0033] The thickness of the insulation layer of the column is δ 立柱 ≤critical thickness δ 临界 Critical thickness δ 临界 =Thickness of the insulation layer of the beam δ 横梁 +0.1× Distance L from the top of the water pipe of the water beam column to the bottom surface of the steel billet.

[0034] The critical thickness δ 临界 This was determined through regression analysis based on FLUENT numerical simulation results and online detection data from the billet black box. When the insulation layer thickness of the water pipe 1 in the water beam column exceeds this critical value, the black mark temperature difference of the billet exiting the furnace will exceed the upper limit specified in the process standard.

[0035] The first refractory insulation layer 3 is bonded to the outer wall of the water pipe 1 of the water beam column, the first refractory insulation layer 3 is bonded to the second refractory insulation layer 4, and the castable working layer 6 is bonded to the third refractory insulation layer 7 by sodium silicate inorganic binder.

[0036] The first refractory insulation layer 3 is composed of an 8-12mm thick nanoporous insulation board with a density of 400-450kg / m³. 3 Its high density helps to rapidly diffuse the concentrated heat flow generated by the anchor hook along a direction parallel to the water pipe, effectively suppressing the thermal bridging effect.

[0037] The second refractory insulation layer 4 is composed of an 8-12mm thick nanoporous ceramic fiber composite material with a density of 280-320kg / m³. 3 Its moderate density and porosity balance thermal insulation performance and mechanical strength, undertaking the main thermal insulation function of the system.

[0038] The thermal bridge blocking sleeve 5 is composed of a 2-3mm thick ceramic fiber felt prefabricated component with a density of 160-200kg / m³. 3 Its low density and high porosity can effectively increase the local thermal resistance of the anchoring area and block the heat transfer path of thermal bridges.

[0039] The density gradient structure, which decreases from the inside out, formed by the first and second refractory insulation layers (3, 4) and the thermal bridge blocking sleeve 5, synergistically optimizes both lateral heat diffusion and radiative heat blocking, significantly reducing interfacial thermal resistance. The synergistic effect of this density gradient design is detailed in Table 1.

[0040] Table 1 Synergistic effect of density gradient design of refractory insulation layer and thermal bridge blocking sleeve. The aforementioned metal mesh temperature-sensitive compensation layer 10 is woven from shape memory alloy (SMA) wire. When the furnace temperature exceeds 600℃, the SMA wire mesh undergoes an austenitic phase transformation and expands, automatically tightening the insulation layer structure to compensate for interface gaps caused by thermal expansion. When the temperature drops, the SMA returns to its initial martensitic state, preventing residual stress cracks. This design effectively solves the sealing failure problem caused by thermal expansion mismatch under high-temperature conditions, thereby further suppressing heat loss.

[0041] The working layer 6 of the castable refractory is composed of a 40-50mm thick room-temperature curing castable refractory. Its chemical composition by mass percentage is: Al2O3: 60%-80%, SiO2: 10%-25%, CaO: 1%-3%, Fe2O3 ≤ 1.5%, and other oxides (MgO, Cr2O3, etc.) ≤ 2.0%. This material uses silica sol as a room-temperature curing agent, eliminating the need for high-temperature baking. The micropores are filled with SiO2 and Al2O3 micropowders, improving the bulk density and mechanical strength. The material has a density of 2650 kg / m³. 3 The maximum operating temperature can reach 1500℃. The core technological advantage of room-temperature curing castables lies in their ability to achieve rapid curing and meet application requirements without high-temperature baking. This characteristic breaks through the limitations of traditional castables, which must undergo high-temperature baking to remove bound moisture and can only be applied to the outermost layer of the insulation system. This provides a structural foundation and technological feasibility for the subsequent layering of the third refractory insulation layer and the spray coating layer.

[0042] The third refractory insulation layer 7 is composed of a 30-40mm thick annular insulating fiber felt. Its material composition by weight percentage is: base material: 55%-60% alumina fiber, 35%-40% ceramic fiber; accelerator: 3.5%-5.5% sodium fluorosilicate. This material has a maximum service temperature of 1500℃ and a density of 350kg / m³. 3 Its thermal conductivity at 600℃ is 0.152 W / (m·K). Its characteristics are: after high-temperature sintering, it undergoes irreversible hardening and shaping, and its refractory performance and resistance to slag erosion are comparable to those of the working layer. At the same time, it also has the characteristics of low density and low thermal conductivity.

[0043] The aforementioned metal-glass clamp 8 is composed of C-shaped or U-shaped paired rings with a width of 10-20mm and a thickness of 3-5mm, connected by a closed structure. Each pair of rings is equipped with two sets of bolts and nuts, which are clamped and fixed by applying tightening torque. The inner diameter of the clamp should be designed to be slightly larger than the outer diameter of the third insulation layer, with a 1-3mm assembly gap reserved. The rings and matching fasteners (bolts and nuts) are made of metal-glass (grade KNC-01), which has a melting point as high as 1750℃ and maintains excellent compressive strength and oxidation resistance even at 1500℃. Due to its extremely high strength and hardness characteristics at high temperatures, the metal-glass material does not undergo plastic deformation until its melting point, thus providing a continuous and stable mechanical constraint force for the third refractory insulation layer under high-temperature conditions. This characteristic plays a key supporting role in achieving the critical thickness increment of the insulation layer.

[0044] The spray coating working layer 9 is composed of a 3-5mm thick zirconium-containing ceramic fiber reinforced coating. The chemical composition of the zirconium-containing ceramic fiber reinforced coating is shown in Table 2.

[0045] Table 2 Chemical composition (wt%) of zirconium-containing ceramic fiber reinforced coatings Characteristics of zirconium-containing ceramic fiber reinforced coatings: ① Core fiber selection: Zirconium-containing ceramic fibers with ZrO2 content ≥8% are used to absorb thermal stress by utilizing their high-temperature phase transformation characteristics. The temperature resistance limit reaches 1600℃, and it can be used for a long time at 1400℃ without pulverization failure. ②Inorganic binder system reinforcement: Aluminum phosphate-silica sol composite liquid is used to react at high temperature to generate AlPO4-SiOC glass phase, which not only enhances the bonding strength (flexural strength ≥6MPa at 1400℃), but also avoids the low-temperature pulverization problem caused by silicate binders. ③ Nano-toughening technology: Add 5% nano-zirconia particles (particle size 10-50nm) to inhibit microcrack propagation through the pinning effect of nanoparticles and enhance the fracture toughness of the material; ④ Anti-slag penetration design: Introduce 15%-20% silicon carbide (SiC) micro powder, and utilize the dense SiO2 film layer generated by its surface oxidation at high temperature to effectively block the penetration of molten slag such as FeO and CaO; ⑤ Gas phase corrosion protection: Add 3% rare earth oxides (La2O3 / CeO2), which preferentially react with SO3 and Cl in the furnace gas. - It reacts with corrosive media to generate stable compounds (such as La2(SO4)3 and CeOCl), which reduces the corrosion of the Al2O3-SiO2 matrix.

[0046] The physical and chemical properties of the coating working layer are shown in Table 3: Table 3 Physicochemical Properties of the Spray Coating Working Layer A construction method for a multi-layer composite thermal insulation structure for water beam columns in a heating furnace includes the following steps: S1. Weld anchor hooks 2 onto the water pipe 1 of the water beam column, with a spacing of 70-80mm, and an effective length of 60%-80% of the total thickness of the first and second refractory insulation layers (3, 4) and the castable working layer 6; S2. Coat the outer wall of the water pipe 1 of the water beam column with sodium silicate inorganic binder and lay the first refractory insulation layer 3 (nano-microporous plate). S3. After coating the first refractory insulation layer 3 with sodium silicate inorganic binder, lay the second refractory insulation layer 4 (nanoporous-ceramic fiber composite layer). S4. After applying 0.5-1.0mm thick asphalt paint to the exposed section of the anchor hook 2, install the thermal bridge blocking sleeve 5; S5. Shape memory alloy wires are interlaced and wound on the rod of the anchor hook to form a mesh structure on the outer surface of the second refractory insulation layer 4, namely the metal mesh temperature-sensitive compensation layer 10. S6. Steel molds are used to support the surface of the metal mesh temperature-sensitive compensation layer 10. The working layer 6 of the castable is poured with room temperature curing castable, fully vibrated, and demolded after room temperature curing. S7. Clean and trim the surface of the castable working layer 6, apply sodium silicate inorganic binder, and then lay the third refractory insulation layer 7 (annular heat insulation fiber felt); after confirming complete adhesion, fix it to the outer surface of the third refractory insulation layer 7 with metal glass clamps 8 at axial intervals of 300-500mm.

[0047] S8. Spray zirconium-containing ceramic fiber reinforced coating evenly onto the outer surface of the fixed third refractory insulation layer 7 to form the spray coating working layer 9. After the spraying is completed, ignite the furnace according to the process system and then put it into operation.

[0048] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0049] Example 1: A construction method for a multi-layer composite insulation structure for water beam columns in a heating furnace, the structure as follows: Figure 1 , Figure 2 As shown; the thickness δ of the insulation layer of the beam in this embodiment 横梁 =60mm, the distance L from the top of the water pipe of the water beam column to the lower surface of the steel billet is 480mm, including the following steps: 1) 20G seamless steel pipes with a specification of φ168mm×20mm are selected as the water pipes for the single water beam column, and anchor hooks 2 are welded to their outer surface. The anchor hooks 2 are made of Cr25Ni20 heat-resistant alloy casting, have a Y-shaped structure, and an effective length of 48mm. The row spacing of the anchor hooks 2 is 75mm, and the spacing between adjacent anchor hooks 2 in the same row is also 75mm.

[0050] 2) After welding, uniformly coat the surface of the water pipe 1 of the single water beam column with sodium silicate inorganic binder, with a coating amount of 1.2 kg / m. 2 And lay the first refractory insulation layer 3 (composed of a 10mm thick nanoporous insulation board with a density of 400kg / m³). 3 ).

[0051] 3) Next, after applying adhesive to the outer surface of the first refractory insulation layer 3, wrap the second refractory insulation layer 4 (composed of a 10mm thick nanoporous ceramic fiber composite felt with a density of 280kg / m³). 3 ).

[0052] 4) After the second refractory insulation layer 4 is completed, apply a 1.0mm thick layer of asphalt paint to the exposed surface of the anchor hook 2, and finally install the thermal bridge blocking sleeve 5 (a 2mm thick precast ceramic fiber felt with a density of 160kg / m³). 3 It is assembled at the top of the anchor hook 2.

[0053] 5) On the outer surface of the second refractory insulation layer 4, a metal mesh temperature-sensitive compensation layer 10 is formed by interlacing shape memory alloy wires with a diameter of 1.0 mm along the root of the anchor hook 2 rod, with a mesh spacing of 45 mm.

[0054] 6) A steel mold is used to support the casting of the working layer 6 of the castable refractory on the surface of the metal mesh temperature-sensitive compensation layer 10. The working layer 6 of the castable refractory is 40mm thick. The chemical composition of the room-temperature curing castable refractory, by mass percentage, is: Al2O3 75%, SiO2 20%, CaO 2.0%, Fe2O3 1.0%, with the remainder being other oxides (MgO, Cr2O3, etc.). Silica sol is used as the binder system as the room-temperature curing agent, eliminating the need for high-temperature baking. Before setting up the mold, a release agent must be evenly coated on the inner surface of the mold to ensure that the working layer achieves the specified smoothness requirements after demolding. During the casting process, sufficient vibration should be applied to ensure the material is dense and to prevent defects such as honeycomb and voids. Demolding is completed after the cast body has cured at room temperature.

[0055] 7) After demolding the working layer 6 of the castable refractory, clean and trim its surface to ensure a smooth, residue-free surface. Then, uniformly coat its surface with sodium silicate inorganic binder at a rate of 1.2 kg / m². 2The third refractory insulation layer 7 is then laid. The third refractory insulation layer 7 consists of a 40mm thick annular insulating fiber felt, with the following material composition by mass fraction: base material: 58% alumina fiber and 37% ceramic fiber; accelerator: 5% sodium fluorosilicate. A spiral winding method is used for construction to ensure full adhesion and complete coverage between the third refractory insulation layer 7 and the castable working layer 6.

[0056] 8) Install KNC-01 metal glass clamps 8. The metal glass clamps 8 consist of two semi-circular rings (radius 205mm) with a width of 10mm and a thickness of 3mm, fastened together by two sets of bolts and nuts, leaving a 2mm assembly gap. The metal glass clamps 8 are arranged at equal intervals of 400mm along the axial direction of the column.

[0057] 9) After the third refractory insulation layer 7 is fixed, a zirconium-containing ceramic fiber reinforced coating is uniformly sprayed onto its outer surface to form a spray coating working layer 9 with a thickness of 3mm. Its chemical composition by mass percentage is as follows: zirconium-containing ceramic fiber (ZrO2 content ≥8%) 52%, silicon carbide (SiC) micro powder 20%, nano-zirconia (particle size 10-50nm) 5%, aluminum phosphate-silica sol composite liquid 15%, rare earth oxide (La2O3 / CeO2) 3%, stainless steel fiber 4%, and organosilicon defoamer 1%. After the spraying is completed, the furnace is ignited and baked, and then put into production operation.

[0058] In this embodiment, the insulation layer thickness is 103mm, which is less than the beam insulation layer thickness δ. 横梁 +0.1× The distance from the upper end of the water pipe of the water beam column to the lower surface of the steel billet is L=108mm.

[0059] Example 2: A construction method for a multi-layer composite insulation structure for water beam columns in a heating furnace, the structure as follows: Figure 3 , Figure 4 As shown, the thickness δ of the insulation layer of the beam in this embodiment is... 横梁 =51mm, the distance L from the top of the water pipe of the water beam column to the lower surface of the steel billet is 500mm, including the following steps: 1) 20G seamless steel pipes with a specification of φ140mm×20mm are selected as the water pipes for the double water beam columns, and anchor hooks 2 are welded to their outer surface. The anchor hooks 2 are made of Cr25Ni20 heat-resistant alloy casting, have a Y-shaped structure, and an effective length of 38mm. The row spacing of the anchor hooks 2 is 70mm, and the spacing between adjacent anchor hooks 2 in the same row is also 70mm.

[0060] 2) After welding, uniformly coat the surface of the water pipes in the double-beam column with sodium silicate inorganic binder, at a coating amount of 1.2 kg / m. 2 And lay the first refractory insulation layer 3 (composed of an 8mm thick nanoporous insulation board with a density of 450kg / m³). 3 ).

[0061] 3) Next, after applying adhesive to the outer surface of the first refractory insulation layer 3, wrap the second refractory insulation layer 4 (composed of an 8mm thick nanoporous ceramic fiber composite felt with a density of 320kg / m³). 3 ).

[0062] 4) After the second refractory insulation layer 4 is completed, apply a 0.8mm thick layer of asphalt paint to the exposed surface of the anchor hook 2, and finally install the thermal bridge blocking sleeve 5 (a 3mm thick precast ceramic fiber felt with a density of 200kg / m³). 3 It is assembled at the top of the anchor hook 2.

[0063] 5) On the outer surface of the second refractory insulation layer 4, a metal mesh temperature-sensitive compensation layer 10 is formed by interlacing shape memory alloy wires with a diameter of 0.8 mm along the root of the anchor hook 2 rod, with a mesh spacing of 50 mm.

[0064] 6) A steel mold is used to support and pour the castable working layer 6 onto the surface of the metal mesh temperature-sensitive compensation layer 10. After being wrapped, the castable working layer 6 forms a capsule-shaped column with a minimum radial thickness of 35mm. The chemical composition of the room-temperature curing castable, by mass percentage, is: Al2O3 70%, SiO2 25%, CaO 3.0%, Fe2O3 0.5%, with the remainder being other oxides (MgO, Cr2O3, etc.). Silica sol is used as the binder system as a room-temperature curing agent, eliminating the need for high-temperature baking. Before setting up the mold, a release agent must be evenly applied to the inner surface of the mold to ensure that the working layer achieves the specified smoothness requirements after demolding. During pouring, thorough vibration is required to ensure material compaction and prevent defects such as honeycomb and voids. Demolding is completed after the cast body has cured at room temperature.

[0065] 7) After demolding the working layer 6 of the castable refractory, clean and trim its surface to ensure a smooth, residue-free surface. Then, uniformly coat its surface with sodium silicate inorganic binder at a rate of 1.2 kg / m². 2 The third refractory insulation layer 7 is then laid. The third refractory insulation layer 7 is composed of a 35mm thick annular insulating fiber felt, with the following material composition by mass fraction: base material: 60% alumina fiber and 36% ceramic fiber; accelerator: 4% sodium fluorosilicate. A spiral winding method is used for construction to ensure full adhesion and complete coverage between the third refractory insulation layer 7 and the castable working layer 6.

[0066] 8) Install KNC-01 metal glass clamps 8 (consisting of two U-shaped rings, each 15mm wide and 5mm thick, fastened together with two sets of bolts and nuts, leaving a 1.5mm assembly gap. The metal glass clamps 8 are arranged at equal intervals of 350mm along the column axis.

[0067] 9) After the third refractory insulation layer 7 is fixed, a zirconium-containing ceramic fiber reinforced coating is uniformly sprayed onto its outer surface to form a spray coating working layer 9 with a thickness of 5mm. The chemical composition of the zirconium-containing ceramic fiber reinforced coating by mass percentage is as follows: zirconium-containing ceramic fiber (ZrO2 content ≥ 8%) 55%, silicon carbide (SiC) micro powder 16%, nano-zirconia (particle size 10-50nm) 5%, aluminum phosphate-silica sol composite liquid 16%, rare earth oxide (La2O3 / CeO2) 3%, stainless steel fiber 4%, and organosilicon defoamer 1%. After the spraying is completed, the furnace is ignited and baked, and then put into production operation.

[0068] In this embodiment, the insulation layer thickness is 91mm, which is less than the beam insulation layer thickness δ. 横梁 +0.1× The distance from the upper end of the water pipe of the water beam column to the lower surface of the steel billet is L=101mm.

[0069] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-layer composite thermal insulation structure for water beam columns in heating furnaces, characterized in that, It includes anchor hooks that are interlaced and fixed to the outer surface of the water pipes of the water beam column, as well as an insulation layer. The insulation layer consists of, from the inside out, a first refractory insulation layer, a second refractory insulation layer, a metal mesh temperature-sensitive compensation layer, a castable working layer, a third refractory insulation layer, and a metal glass clamp fastened to the surface of the third refractory insulation layer. The third refractory insulation layer fastened by the metal glass clamp has a spray coating working layer on the outside. The anchoring hook is covered by a first and a second refractory insulation layer, a metal mesh temperature-sensitive compensation layer and a castable working layer, and its end is fitted with a thermal bridge blocking sleeve; the material density of the first refractory insulation layer, the second refractory insulation layer and the thermal bridge blocking sleeve are distributed in a gradient decreasing distribution, forming a gradient density thermal insulation structure.

2. The multi-layer composite thermal insulation structure for a water beam column of a heating furnace according to claim 1, characterized in that, The thickness δ of the insulation layer 立柱 ≤critical thickness δ 临界 Critical thickness δ 临界 =Thickness of the insulation layer of the beam δ 横梁 +0.1× Distance L from the top of the water pipe of the water beam column to the bottom surface of the steel billet.

3. The multi-layer composite thermal insulation structure for a water beam column of a heating furnace according to claim 1, characterized in that, The first refractory insulation layer is bonded to the outer wall of the water pipe of the water beam column, the first refractory insulation layer is bonded to the second refractory insulation layer, and the castable working layer is bonded to the third refractory insulation layer with sodium silicate inorganic adhesive.

4. A multi-layer composite thermal insulation structure for a water beam column of a heating furnace according to claim 1, characterized in that, The first refractory insulation layer is composed of a nanoporous heat insulation board, the second refractory insulation layer is composed of a nanoporous-ceramic fiber composite material, and the third refractory insulation layer is composed of annular heat insulation fiber felt. The composition of the heat insulation fiber felt by mass percentage is as follows: Substrate: 55%-60% alumina fiber, 35%-40% ceramic fiber; Accelerator: 3.5%-5.5% sodium fluorosilicate.

5. A multi-layer composite thermal insulation structure for a water beam column of a heating furnace according to claim 1, characterized in that, The thermal bridge blocking sleeve is composed of a ceramic fiber felt prefabricated component.

6. A multi-layer composite thermal insulation structure for a water beam column of a heating furnace according to claim 1, characterized in that, The temperature-sensitive compensation layer of the metal mesh is woven from shape memory alloy wires with a mesh spacing of 45-55mm.

7. A multi-layer composite thermal insulation structure for a water beam column of a heating furnace according to claim 1, characterized in that, The working layer of the castable is formed by casting a room-temperature curing castable, and its chemical composition by mass percentage is: Al2O3: 60%-80%, SiO2: 10%-25%, CaO: 1%-3%, Fe2O3≤1.5%, and other oxides≤2.0%.

8. A multi-layer composite thermal insulation structure for a water beam column of a heating furnace according to claim 1, characterized in that, The metal-glass clamp is assembled from paired metal-glass rings through a closed structure.

9. A multi-layer composite thermal insulation structure for a water beam column of a heating furnace according to claim 1, characterized in that, The spray coating working layer is composed of a zirconium-containing ceramic fiber reinforced coating. The chemical composition of the zirconium-containing ceramic fiber reinforced coating by mass percentage is: zirconium-containing ceramic fiber with ZrO2 ≥ 8% : 40%-60%; Silicon carbide micro powder: 15%-20%; nano-zirconia: 5%; aluminum phosphate-silica sol composite solution: 15%-20%; rare earth oxides: 3%; stainless steel fiber: 4%; defoamer: 1%.

10. A construction method for a multi-layer composite thermal insulation structure for a water beam column of a heating furnace according to claim 1, characterized in that, Includes the following steps: S1. Weld anchor hooks to the water pipes of the water beam column, with a spacing of 70-80mm, and an effective length of 60%-80% of the total thickness of the first and second refractory insulation layers and the castable working layer; S2. Coat the outer wall of the water pipe of the water beam column with sodium silicate inorganic binder and lay the first refractory insulation layer; S3. Apply sodium silicate inorganic binder to the outside of the first refractory insulation layer, and then lay the second refractory insulation layer; S4. After applying a 0.5-1.0mm thick layer of asphalt paint to the exposed section of the anchor hook, install the thermal bridge blocking sleeve; S5. Shape memory alloy wires are interlaced and wound on the rod of the anchor hook to form a mesh structure on the outer surface of the second refractory insulation layer, which is the metal mesh temperature-sensitive compensation layer. S6. Use steel molds to support the surface of the metal mesh temperature-sensitive compensation layer, pour the castable working layer with room temperature curing castable, vibrate it fully, and demold after room temperature curing. S7. Clean and trim the surface of the castable working layer, apply sodium silicate inorganic binder, and then lay the third refractory insulation layer; after confirming complete adhesion, use metal and glass clamps to fix the third refractory insulation layer at intervals on the outer surface; S8. Spray zirconium-containing ceramic fiber reinforced coating evenly onto the outer surface of the fixed third refractory insulation layer to form a spray coating working layer. After the spraying is completed, ignite the furnace according to the process specifications and then put it into operation.

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