CSP soaking pit furnace wall thermal insulation material, structure and preparation method of CSP soaking pit furnace wall thermal insulation material

Abstract

The invention discloses a CSP soaking pit furnace wall thermal insulation material which is of a gradient composite structure comprising an instantaneous high temperature resistant inner layer, a thermal insulation middle layer and a radiation heat exchange outer layer, and the instantaneous high temperature resistant inner layer is made of a composite material comprising nano aerogel and high temperature resistant whiskers; the heat insulation middle layer is made of a nano-particle modified ceramic fiber material; and the radiation heat exchange outer layer adopts a ceramic coating with high infrared reflectivity. The overall heat conductivity coefficient is reduced through the synergistic effect of the low heat conductivity of the inner layer, the high-temperature shrinkage resistance of the middle layer and the radiation heat dissipation performance of the outer layer, good instantaneous high temperature resistance and high-temperature stability are considered, and the heat preservation effect is remarkably enhanced; and in combination with various surface connection improvement means, a heat conduction path can be effectively prolonged, a heat bridge effect can be blocked, heat loss is further reduced, heat energy loss and operation energy consumption of the furnace body are remarkably reduced, and rapid repair is facilitated.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metallurgical industrial furnace, and particularly relates to a CSP soaking furnace wall thermal insulation material, a structure and a preparation method thereof. BACKGROUND

[0002] The traditional CSP soaking furnace wall thermal insulation material often adopts unshaped refractory material, aluminum silicate fiber or light refractory brick, which can meet the basic heat insulation requirement, but has a high thermal conductivity, insufficient heat insulation performance, large heat loss of the furnace body, and high energy consumption in long-term operation. In addition, under high-temperature environment, such materials are prone to shrinkage deformation, form gaps and accelerate the attenuation of thermal insulation performance, and the overall pouring structure design makes maintenance extremely cumbersome, and a large area needs to be replaced after furnace cooling, which seriously affects the production efficiency.

[0003] In the prior art, the furnace wall structure generally relies on metal anchors to fix the thermal insulation layer, and the high thermal conductivity of metal parts can directly cause thermal bridge effect, resulting in abnormal local temperature fluctuation of the furnace shell, aggravating problems such as oxidation and stress damage. In addition, the traditional thermal insulation material system also has the problem of difficult effective balance between high-temperature resistance and low thermal conductivity, and the lack of modular block technology also leads to difficult quick repair when local damage occurs, which cannot effectively adapt to the requirements of high efficiency and energy saving and flexible maintenance of industrial furnaces. SUMMARY

[0004] The main purpose of the present application is to provide a CSP soaking furnace wall thermal insulation material and structure to solve the problems of high thermal conductivity of traditional thermal insulation materials, high-temperature shrinkage cracking induced thermal insulation performance attenuation, and to simultaneously inhibit the local heat dissipation abnormality caused by the thermal bridge effect of metal anchors, significantly reduce the heat loss and operating energy consumption of the furnace body, and facilitate quick repair.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows: A CSP soaking furnace wall thermal insulation material adopts a gradient composite structure including an anti-instantaneous high-temperature inner layer, a heat insulation intermediate layer and a radiation heat exchange outer layer, wherein the anti-instantaneous high-temperature inner layer adopts a composite material including nano aerogel and high-temperature resistant whisker; the heat insulation intermediate layer adopts nano particle modified ceramic fiber material; and the radiation heat exchange outer layer adopts high-infrared reflectivity ceramic coating.

[0006] In the above scheme, the nano aerogel is silicon-based aerogel; and the high-temperature resistant whisker is silicon carbide whisker, which is uniformly dispersed in the nano aerogel matrix.

[0007] Further, the silicon-based aerogel is in powder form, and the average pore size is 20-50 nm.

[0008] Further, the content of SiC in the silicon carbide whisker is ≥95.5wt%, the diameter is 0.5-2um, and the aspect ratio is 40-60.

[0009] In the above scheme, the mass ratio of the high-temperature resistant whisker to the nano-aerogel is 1:0.15-0.35.

[0010] In the above scheme, in the nano-particle modified ceramic fiber material, the nano-particles are zirconium oxide or aluminum oxide particles; the particle size is 30-50 nm; the diameter of the ceramic fiber material is 3-5 um, and the aspect ratio is 10 4 ~10 5 .

[0011] Further, in the ceramic fiber material, the total content of Al2O3 and SiO2 is ≥95%, and the main crystal phase is mullite.

[0012] Further, the preparation method of the nano-particle modified ceramic fiber material comprises the following steps: fully ball-milling and mixing bauxite and nano-particles (zirconium oxide or aluminum oxide), pressing into a block, and then putting into a high-temperature electric arc furnace for melting at >2000℃, and then, introducing the obtained melt into a centrifugal spinning machine to be stretched into fibers under the action of high-speed centrifugal force, and part of the nano-particles which are not completely dissolved are wrapped inside the formed ceramic fibers or act as heterogeneous nucleation points to refine mullite microcrystals, so that the nano-particle modified ceramic fiber material is finally obtained.

[0013] Further, the mass ratio of the bauxite to the nano-particles is 1:(0.05-0.18).

[0014] In the above scheme, the ceramic coating is a perovskite type infrared ceramic layer; and the infrared reflectivity thereof is ≥0.93.

[0015] Further, the ceramic coating adopts a perovskite type infrared high-emissivity thermal barrier coating material; and the perovskite type infrared high-emissivity thermal barrier coating material comprises the following components in mass percentage: Ca / Cr co-doped LaAlO3 (perovskite radiation component) 30-45%, aluminum dihydrogen phosphate aqueous solution 10-20%, calcium hexaluminate fine powder (heat insulation filler) 35-55%, and polycarboxylic acid type high-efficiency dispersant 0.5-1.5%.

[0016] Further, in the Ca / Cr co-doped LaAlO3, the Ca doping amount is 1.5-3wt%, and the Cr doping amount is 1-2wt%.

[0017] Further, the concentration of the aluminum dihydrogen phosphate aqueous solution is 45-55wt%.

[0018] In the above scheme, the particle size of the calcium hexaluminate fine powder is 3-8um.

[0019] The application further provides a CSP soaking furnace wall heat preservation structure, which comprises an anti-instantaneous high-temperature inner layer, a heat insulation intermediate layer and a radiation heat exchange outer layer which are sequentially bonded, wherein the outer surface of the anti-instantaneous high-temperature inner layer is further bonded with an inner protective layer, and the outer surface of the radiation heat exchange outer layer is further provided with a furnace shell connecting layer (in contact with the outer shell); the inner protective layer is made of silicon carbide fiber reinforced zirconium carbide porous ceramic, and the furnace shell connecting layer is made of a corrugated metal ceramic composite plate.

[0020] Further, in the silicon carbide fiber reinforced zirconium carbide porous ceramic, a zirconium carbide ceramic matrix and silicon carbide fibers are contained, the volume fraction of the silicon carbide fibers is 20-30%, the pore size distribution range of the porous structure is 10-50 um, the long-term use temperature is greater than or equal to 1400 DEG C, and the thermal expansion coefficient is 4-8*10 -6 (1200 DEG C*24h), and the compressive strength is greater than or equal to 150 MPa.

[0021] In the above scheme, in the corrugated metal ceramic composite plate, the metal layer can be made of 304H heat-resistant steel, the ceramic layer can be made of Al2O3 ceramic, etc., the thickness ratio of the metal layer is 80-90%, and the thickness of the ceramic layer is 0.5-2 mm.

[0022] In the above scheme, the anti-instantaneous high-temperature inner layer and the heat insulation intermediate layer are bonded by using nano-alumina sol or aluminum phosphate-based ceramic adhesive, and the heat insulation intermediate layer and the radiation heat exchange outer layer are bonded by using zirconia sol or potassium silicate-based adhesive.

[0023] Further, the inner protective layer and the anti-instantaneous high-temperature inner layer are bonded by using silicon carbide reaction sintering adhesive or zirconium carbide nano slurry, and the radiation heat exchange outer layer and the furnace shell connecting layer are bonded by using Ni-Al2O3 metal ceramic adhesive.

[0024] Further, the modular heat preservation material is fixed by using Z-shaped ceramic nails and V-shaped metal anchoring members (which can be made of ordinary carbon steel, etc.), the Z-shaped ceramic nails have a continuous bending structure, one end of the Z-shaped ceramic nails is embedded in the interior of the heat preservation material and keeps a suspended gap with the interior, and the other end of the Z-shaped ceramic nails is connected with the furnace shell, so that the heat bridge effect is blocked by prolonging the heat conduction path (without using the above-mentioned furnace shell connecting means, which is prone to cause local temperature abnormal fluctuation of the furnace shell and other problems).

[0025] Further, the modular block unit is a rectangular module with a standardized size, expansion joints are reserved between the modules and filled with high-temperature resistant adhesive, the heat preservation unit elements are tightly and stably combined together by using the high-temperature resistant adhesive, so that a good heat preservation effect is achieved.

[0026] Further, the high-temperature resistant adhesive can be selected from one or more of silicate-based adhesive, phosphate-based adhesive, silica sol and alumina sol-based adhesive, etc.

[0027] Compared with the prior art, the beneficial effects of the present invention include: 1) The CSP homogenizing furnace wall insulation material of the present invention adopts a gradient composite structure. The overall thermal conductivity is reduced by the synergistic effect of the low thermal conductivity of the inner layer, the high temperature shrinkage resistance of the middle layer, and the radiative heat dissipation of the outer layer, while taking into account good high temperature stability and significantly enhancing the insulation effect. Among them, the nano-aerogel introduced in the anti-instantaneous high temperature inner layer can effectively reduce the thermal conductivity of the anti-instantaneous high temperature inner layer and greatly improve the thermal insulation performance. At the same time, the composite addition of silicon carbide high temperature resistant whiskers, which are uniformly dispersed in the nano-aerogel matrix, can effectively improve the anti-instantaneous high temperature capability of the inner layer. 2) In the CSP homogenizing furnace wall insulation structure adopted in this invention, the perovskite infrared ceramic is combined with components such as Ca / Cr co-doped LaAlO3 and calcium hexaaluminate, which can achieve a high near-mid-infrared high-temperature emissivity and further enhance the heat exchange effect in the furnace. At the same time, the aluminum dihydrogen phosphate aqueous solution will decompose at high temperature and eventually form an amorphous aluminum phosphate ceramic phase, which has certain toughness and creep ability, and can effectively absorb and buffer the thermal stress generated inside the coating due to frequent furnace start-up and shutdown or temperature fluctuations.

[0028] 3) Based on the gradient composite furnace wall insulation structure, this invention further combines various surface connection improvement methods, which can effectively extend the heat conduction path and block the thermal bridge effect, thereby further reducing heat loss. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the CSP furnace wall insulation material and structure provided in one embodiment of the present invention.

[0030] Explanation of reference numerals in the attached drawings: 1-Inner protective layer, 2-Step composite layer-inner layer, 3-Step composite layer-middle layer, 4-Step composite layer-outer layer, 5-Furnace shell connecting layer, 6-Z-type ceramic nail, 7-V-type anchor, 8-First adhesive, 9-Second adhesive, 10-Third adhesive, 11-Fourth adhesive. Detailed Implementation

[0031] To further understand the present invention, the following detailed description of a paste preparation method for high-precision thin-layer photopolymerization printing provided by the present invention is provided in conjunction with embodiments. The scope of protection of the present invention is not limited by the following embodiments.

[0032] Example 1 like Figure 1As shown, the present application provides a CSP soaking furnace wall insulation structure, which comprises an inner protective layer 1, an anti-transient high temperature inner layer 2, an insulating intermediate layer 3, a radiation heat exchange outer layer 4 and a furnace shell connecting layer 5 arranged in sequence; wherein V-shaped anchoring members 7 are arranged in the inner protective layer 1, and the inner protective layer 1, the anti-transient high temperature inner layer 2, the insulating intermediate layer 3, the radiation heat exchange outer layer 4 and the furnace shell connecting layer 5 are connected by Z-shaped ceramic nails connected at one end, and the other end is connected with the furnace shell; in addition, the adhesives used between each two functional layers are first adhesive 8, second adhesive 9, third adhesive 10 and fourth adhesive 11 in sequence.

[0033] The CSP soaking furnace wall insulation material mainly includes a three-layer gradient composite structure: the inner layer 2 is an anti-transient high temperature layer, which is a composite material formed by nano aerogel and high-temperature resistant whisker in a mass ratio of 1:5, wherein the nano aerogel is a silicon-based aerogel powder with an average pore size of 20-50 nm and a thermal conductivity of 0.035 W / m·K (hot surface temperature 400℃); the high-temperature resistant whisker is silicon carbide whisker with a SiC content of ≥95.5%, a diameter of 0.5-2um and an average aspect ratio of 50, and the mass ratio of silicon carbide whisker to nano aerogel is 1:0.2, uniformly dispersed in the aerogel matrix; The middle layer 3 needs long-term insulation, which adopts a nano-particle modified ceramic fiber layer; the specific preparation method of the nano-particle modified ceramic fiber layer includes the following steps: high-purity bauxite and nano-particles (zirconium oxide or aluminum oxide) are fully ball-mixed in a mass ratio of 1:0.1, then pressed into a block and put into a high-temperature electric arc furnace for melting at 2100℃, then the aluminum-silicon melt stream is introduced into a centrifugal fiberizer to be drawn into fibers under the action of high-speed centrifugal force, and part of the nano-particles that are not completely dissolved are wrapped inside the fibers or act as heterogeneous nucleation points to refine the mullite microcrystals, finally obtaining a nano-particle modified ceramic fiber material (diameter 3-5um, aspect ratio 10 4 ~10 5 ); In the ball milling step, a wet process is adopted, zirconium oxide grinding balls and ethanol are used as medium, and the mass ratio of material:ball:medium is 1:3:1.2, ball milling is carried out at 300rpm for 12 hours to ensure uniform dispersion of nano-particles. In the centrifugal fiberizing step, the melt flow is controlled at 2kg / min, the spinning disk rotates at 7500rpm, and 0.2MPa compressed air is used for secondary drawing; under this condition, modified ceramic fibers with a diameter of 3-5um and an aspect ratio of 10 4 ~10 5 can be stably prepared.

[0034] The outer layer 4 is a radiation heat exchange layer, which adopts a ceramic coating with high infrared reflectivity. The raw materials and their mass percentages in the perovskite-type infrared high emissivity thermal barrier coating are as follows: 40% Ca / Cr co-doped LaAlO3 (perovskite radiation component), 15% aluminum dihydrogen phosphate aqueous solution (concentration of 50wt%), 44% calcium hexaaluminate fine powder (thermal insulation filler), and 1% polycarboxylic acid dispersant (commercially available). After mixing and stirring for 15 minutes, the resulting coating is applied to the middle layer 3 with a thickness of 0.5 mm. The gradient composite structure reduces the overall thermal conductivity through the synergistic effect of the low thermal conductivity of the inner layer 2, the high-temperature shrinkage resistance of the middle layer 3, and the radiative heat dissipation of the outer layer 4. An inner protective layer 1 that directly contacts the high-temperature melt and a furnace shell connecting layer 5 that contacts the outer shell are provided on both sides of the gradient composite insulation layer. The inner protective layer 1 is made of silicon carbide fiber-reinforced zirconium carbide porous ceramic (the volume fraction of silicon carbide fiber is 10%; the pore size distribution range of the porous structure is 10~50um). The furnace shell connecting layer 5 is made of corrugated metal-ceramic composite plate (304H heat-resistant steel / Al2O3 ceramic composite plate), in which the metal layer accounts for 85% of the thickness and the ceramic layer is 5 mm thick.

[0035] Furnace wall insulation structure: like Figure 1 As shown, Z-shaped ceramic nails 6 and V-shaped anchors 7 are used to fix the modular insulation material. The Z-shaped ceramic nail 6 has a continuous bending structure. One end is embedded in the insulation material and maintains a floating gap with the interior, while the other end is connected to the furnace shell, thus blocking the thermal bridging effect by extending the heat conduction path.

[0036] The modular segmented unit is a rectangular module of standardized size. Expansion joints are reserved between modules and filled with adhesive. The inner protective layer 1 is bonded to the tiered composite layer-inner layer 2 by the first adhesive 8, the tiered composite layer-inner layer 2 is bonded to the tiered composite layer-middle layer 3 by the second adhesive 9, the tiered composite layer-middle layer 3 is bonded to the tiered composite layer-outer layer 4 by the third adhesive 10, and the tiered composite layer-outer layer 4 is bonded to the furnace shell connecting layer 5 by the fourth adhesive 11. Among them, the first adhesive 8 is a silicon carbide reactive sintering adhesive (USA Saint-Gobain Corporation, HRJ-15800 model), the second adhesive 9 is a nano alumina sol (Xuancheng Jingrui New Materials Co., Ltd., VK-L30 model), the third adhesive 10 is a potassium silicate-based adhesive (Qingdao Hongxing Chemical Research Institute, G50-1 model), and the fourth adhesive 11 is a Ni-Al2O3 cermet adhesive (produced by Xuancheng Jingrui New Materials Co., Ltd., JR006 model). By using the different types of high-temperature resistant adhesives described above, the present invention can tightly and firmly bond the insulation components together, thereby promoting a good insulation effect.

[0037] The rectangular module combined by the above heat preservation components is prepared into a standard sample by reducing the thickness in the same proportion, and the heat insulation performance is detected by using a flat plate heat conduction instrument. The results show that when the hot surface temperature is 400 and 800 DEG C, the thermal conductivity is 0.08 and 0.15, respectively. After 3 years of use, it is found that there is no obvious crack between the modules, and the high temperature shrinkage cracking resistance is excellent.

[0038] Example 2 A CSP soaking furnace wall heat preservation material and structure, which is substantially the same as the structure and preparation method of Example 1, and the difference is that the mass ratio of silicon carbide whisker to nano aerogel in the composite material of nano aerogel and high-temperature-resistant whisker in the anti-instantaneous high-temperature layer is 1:0.35.

[0039] The rectangular module combined by the above heat preservation components is prepared into a standard sample by reducing the thickness in the same proportion, and the heat insulation performance is detected by using a flat plate heat conduction instrument. The results show that when the hot surface temperature is 400 and 800 DEG C, the thermal conductivity is 0.08 and 0.15, respectively. After 3 years of use, it is found that there is no obvious crack between the modules, and the high temperature shrinkage cracking resistance is excellent.

[0040] Comparative Example 1 A refractory fiber module for a CSP soaking furnace, which specifically uses a zirconium-containing aluminum silicate refractory fiber module.

[0041] After testing, when the hot surface temperature is 400 and 800 DEG C, the thermal conductivity is 0.14 and 0.32, respectively.

[0042] Comparative Example 2 A CSP soaking furnace wall heat preservation material and structure, which is substantially the same as Example 1, and the difference is that the intermediate heat insulation layer is made of aluminum silicate refractory fiber material with a diameter of 3-5 um and a length-diameter ratio of greater than or equal to 10. 4 .

[0043] The rectangular module combined by the above heat preservation components is prepared into a standard sample by reducing the thickness in the same proportion, and the heat insulation performance is detected by using a flat plate heat conduction instrument. The results show that when the hot surface temperature is 400 and 800 DEG C, the thermal conductivity is 0.08 and 0.15, respectively. After 3 years of use, it is found that there is no obvious crack between the modules, and the high temperature shrinkage cracking resistance is excellent.

[0044] Comparative Example 3 A CSP soaking furnace wall heat preservation material and structure, which is substantially the same as Example 1, and the difference is that the intermediate heat insulation layer 2 is made of silicon-based nano aerogel, instead of the composite material of nano aerogel and high-temperature-resistant whisker.

[0045] The rectangular module combined by the above heat preservation components is prepared into a standard sample by reducing the thickness by equal proportion, and the heat insulation performance is detected by using a flat plate heat conduction instrument, and the results show that when the hot surface temperature is 400 and 800 DEG C, the thermal conductivity is 0.06 and 0.12 respectively. After 3 years of use, the observation during the shutdown maintenance period shows that the module has inward concave in some areas, and cracking and fire leakage phenomenon in individual areas, although the new module has heat insulation performance according to embodiment 1, but after long-term use at high temperature, the structure collapses, which leads to a significant decrease in the overall heat insulation performance.

[0046] The outer layer of the application adopts the "function superposition" idea, realizing the "structure-function" integration. The aluminum dihydrogen phosphate binder forms a strong and tough ceramic network in situ at high temperature, solving the peeling problem caused by thermal expansion mismatch; the calcium hexaluminate filler has the dual functions of heat insulation and rigid skeleton, synergistically inhibiting high-temperature shrinkage, guaranteeing long-term structural stability and heat insulation; the dispersant ensures uniform distribution of components, so that excellent thermal shock resistance and high radiation rate can still be maintained under severe thermal cycling, realizing the dual improvement of performance and service life, and the high-temperature stability of the application cannot be guaranteed without the introduction of the aluminum dihydrogen phosphate binder.

[0047] The specific embodiment is only an explanation of the application, and is not a limitation of the application. Those skilled in the art can make modifications to the embodiment without creative contribution according to the needs after reading the specification, but as long as it is within the scope of the claims of the application, it is protected by the patent law.

Claims

1. A CSP soaking pit wall insulation material, characterized by, The gradient composite structure comprises an anti-transient high-temperature inner layer, a heat-insulating intermediate layer and a radiation heat exchange outer layer, wherein the anti-transient high-temperature inner layer comprises a composite material containing nano-aerogel and high-temperature resistant whisker; the heat-insulating intermediate layer comprises nano-particle modified ceramic fiber material; and the radiation heat exchange outer layer comprises a high-infrared reflectivity ceramic coating.

2. The CSP soaking pit wall insulation material of claim 1, wherein, The nano-aerogel is silicon-based aerogel; and the high-temperature resistant whisker is silicon carbide whisker.

3. The CSP soaking pit wall insulation material of claim 1, wherein, The mass ratio of the high-temperature resistant whisker to the nano-aerogel is 1:0.15-0.

35.

4. The CSP soaking pit wall insulation material of claim 1, wherein, The nanoparticles in the nanoparticle-modified ceramic fiber material are zirconium oxide or aluminum oxide particles, the particle size is 30-50 nm, the diameter of the ceramic fiber material is 3-5 um, and the aspect ratio is 10 4 ~10 5 .

5. The CSP soaking pit wall insulation material of claim 1, wherein The ceramic coating is a perovskite type infrared ceramic layer. The infrared reflectivity of the perovskite type infrared ceramic layer is above 0.

93.

6. The CSP soaking pit wall insulation material of claim 5, wherein, The perovskite type infrared ceramic layer adopts a perovskite type infrared high-emissivity thermal barrier coating, which comprises the following components in mass percentage: Ca / Cr co-doped LaAlO3 30-45%, aluminum dihydrogen phosphate aqueous solution 10-20%, calcium hexaluminate fine powder 35-55%, and polycarboxylic acid high-efficiency dispersant 0.5-1.5%.

7. The CSP soaking pit wall insulation material of claim 6, wherein In the Ca / Cr co-doped LaAlO3, the Ca doping amount is 1.5-3wt%, and the Cr doping amount is 1-2wt%.

8. A CSP soaking pit wall insulation structure based on the CSP soaking pit wall insulation material according to claim 1, characterized by, The gradient composite structure comprises an anti-transient high-temperature inner layer, a heat-insulating intermediate layer and a radiation heat exchange outer layer, wherein the anti-transient high-temperature inner layer comprises an anti-transient high-temperature inner layer, a heat-insulating intermediate layer and a radiation heat exchange outer layer, wherein the outer surface of the anti-transient high-temperature inner layer is bonded with an inner protective layer, and the outer surface of the radiation heat exchange outer layer is bonded with a furnace shell connecting layer; the material of the inner protective layer is silicon carbide fiber reinforced zirconium carbide porous ceramic, and the furnace shell connecting layer is a corrugated metal ceramic composite plate.

9. The CSP soaking pit wall insulation structure according to claim 8, wherein In the silicon carbide fiber reinforced zirconium carbide porous ceramic, the zirconium carbide ceramic matrix and the silicon carbide fiber are contained, and the volume fraction of the silicon carbide fiber is 10-30%; the pore size distribution range of the porous structure is 10-50um.

10. The CSP soaking pit wall insulation structure according to claim 8, wherein In the corrugated metal ceramic composite plate, the thickness ratio of the metal layer is 80-90%.

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