A high-temperature rollable micro-nano multi-level porous inorganic composite thermal insulation material and its low-carbon preparation method

Abstract

The present invention discloses a high-temperature curlable micro-nano multi-level porous inorganic composite thermal insulation material and its low-carbon preparation method, belonging to the technical field of inorganic thermal insulation materials. The composite thermal insulation material of the present invention has a three-layer structure of inner, middle and outer layers; the outer layer has the most fibers and contains a certain amount of water, giving the material better curling properties; the middle layer has the largest porosity and forms micron-nano multi-level cavities to improve thermal insulation performance; the inner layer improves the material's high temperature resistance. The composite thermal insulation material of the present invention has good comprehensive properties, such as fire resistance, low thermal conductivity (small change in thermal conductivity at high temperatures), and good flexibility.

Description

Technical Field

[0001] The present invention relates to the technical field of inorganic thermal insulation materials, in particular to a high-temperature rollable micro-nano multi-level porous inorganic composite thermal insulation material and a low-carbon preparation method thereof. Background Art

[0002] High-temperature equipment and the pipes between high-temperature equipment need to be equipped with thermal insulation materials. Currently, the thermal insulation materials for high-temperature pipes are mainly made of soft and curlable cotton felt materials, such as rock wool, aluminum silicate wool, glass wool, etc., which have good curling properties and can be wrapped around the pipe in multiple layers according to the required thickness for insulation. Hard inorganic thermal insulation materials with a certain strength that are prefabricated into a tube shell shape, such as calcium silicate and expanded perlite materials, can also be used. They can be prefabricated according to the diameter of the insulated pipe and then buckled onto the pipe for insulation. The above-mentioned soft or hard thermal insulation materials are usually made of one main raw material and a small amount of auxiliary materials. The pore size formed inside the material is relatively simple, so that its thermal conductivity increases rapidly with increasing temperature. Especially when used at higher temperatures, soft materials are easy to deform, resulting in large gaps between the thermal insulation material and the insulation equipment, such as the pipe, causing serious heat loss; while hard materials are easy to pulverize and easily become disconnected from the pipe, losing their thermal insulation ability. In recent years, multi-cavity ceramic composite insulation materials have emerged, which are somewhere between soft and hard materials. These materials are flexible, resist deformation, and offer excellent thermal insulation performance at higher temperatures. However, the preparation of current multi-cavity ceramic composite insulation materials requires a long drying process, resulting in high energy consumption and a long production cycle. Furthermore, these materials suffer from poor strength and prone to cracking. Their thermal insulation performance is still insufficient, and their curling properties need to be improved. Therefore, the development of inorganic insulation materials with improved thermal insulation properties remains an unresolved issue. Summary of the Invention

[0003] The present invention aims to provide a rollable, micro-nano multi-level porous inorganic composite thermal insulation material for high-temperature use and a low-carbon production method thereof to address the aforementioned problems of the prior art. The composite thermal insulation material of the present invention exhibits excellent overall performance (fire resistance, low thermal conductivity (small change in thermal conductivity at high temperatures), and good flexibility), is easy to use, and has a low production cost, conforming to current trends in low-carbon production.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] One of the technical solutions of the present invention is a high-temperature rollable micro-nano multi-level porous inorganic composite thermal insulation material, wherein the composite thermal insulation material has a three-layer structure of inner, middle and outer layers;

[0006] The raw materials of the inner layer include, by weight: 45 to 55 parts of oxide ceramic fibers, 25 to 35 parts of oxide ceramic hollow beads, 4 to 6 parts of perlite, 4 to 6 parts of modified graphene, 1 to 3 parts of a binder, and 2 to 4 parts of a dispersant.

[0007] The raw materials of the middle layer include, by weight: 25-35 parts of oxide ceramic fibers, 45-55 parts of oxide ceramic hollow beads, 8-12 parts of silica aerogel powder, 4-6 parts of binder and 4-6 parts of dispersant;

[0008] Calculated by weight, the raw materials of the outer layer include: 45-55 parts of glass fiber, 25-35 parts of hollow glass beads, 8-12 parts of wood cellulose, 4-6 parts of binder and 4-6 parts of dispersant.

[0009] Furthermore, the oxide ceramic hollow beads include alumina hollow microbeads and / or silica hollow microbeads;

[0010] The oxide ceramic fibers include one or more of alumina fibers, zirconia fibers, and aluminum silicate fibers;

[0011] The modified graphene is graphene coated with chromium or iron on the surface, and the coating thickness is 0.1-0.2 μm; the sheet diameter of the graphene is 10-20 μm, and the thickness is 100-300 nm.

[0012] The iron or chromium coated on the surface of graphene can effectively reflect thermal radiation from high-temperature pipes, further improving the thermal insulation effect.

[0013] Further, the binder includes polyvinyl alcohol;

[0014] The dispersant consists of a foaming agent and polyborosiloxane in a weight ratio of 3:2.

[0015] Furthermore, the glass fiber has a diameter of 5 to 10 microns and a length of 7 to 9 centimeters;

[0016] The diameters of the wood cellulose and oxide ceramic fibers are both 5 to 10 microns and the lengths are both 3 to 5 centimeters;

[0017] The particle size of the oxide ceramic hollow beads is 10 to 30 microns;

[0018] The particle size of the agglomerates of the silica aerogel powder is 10 to 50 microns;

[0019] There are a large number of nanopores inside the agglomerates of silica aerogel powder. Together with the oxide ceramic hollow beads, they fill the larger pores formed by the fibers to form multi-level pores ranging from microns to nanometers, which greatly improves the thermal insulation performance, increases the overall density of the composite insulation material, and improves its strength.

[0020] The size of the perlite is 200 mesh;

[0021] The particle size of the hollow glass beads is 20 to 50 microns.

[0022] Furthermore, in the raw materials of the middle layer, the oxide ceramic hollow beads are composed of silicon oxide hollow microspheres and aluminum oxide hollow microspheres in a weight ratio of 30:20; in the raw materials of the inner layer, the oxide ceramic hollow beads are composed of silicon oxide hollow microspheres and aluminum oxide hollow microspheres in a weight ratio of 20:10;

[0023] The silica hollow microspheres and the alumina hollow microspheres are distributed differently in the middle layer and the inner layer, forming different porosities, which has a great effect on improving the thermal insulation performance of the thermal insulation material.

[0024] The inner layer of the composite insulation material contacts high-temperature components, such as high-temperature pipes. The outer layer is bonded to the inner layer and exposed to the external environment. The middle layer connects the inner and outer layers. The porosity of the composite insulation material increases from the outer layer to the middle layer, while the porosity decreases from the middle layer to the inner layer.

[0025] Oxide ceramic fiber materials are resistant to high temperatures, and oxide ceramic fibers of a certain length (about 3 to 5 cm) can give the insulation material good overall connectivity and curlability. The oxide ceramic fibers used in the middle and inner layers are slightly shorter, which can increase the contact area between the fibers and the particles, which is beneficial for improving the porosity. The glass fibers in the outer layer are slightly longer, which can increase the flexibility of the material. However, the fiber length should not be too long or too short. Fiber length that is too long (up to 10 cm) is not conducive to material mixing and mixing uniformity, while length that is too short (less than 3 cm) affects the toughening effect and curlability. The fibers in the outer layer include longer glass fibers and shorter wood cellulose fibers, which give it a better toughening effect. The higher fiber ratio in the outer and inner layers allows the material to achieve better curling properties. Hollow glass beads and oxide ceramic beads act as fillers between the fibers, filling the larger pores formed by the fibers and improving thermal insulation. They also impart strength to the insulation material, preventing it from deforming under its own weight and at high temperatures. In the middle layer, the addition of oxide ceramic hollow beads and silica aerogel powder creates multi-level pores at micrometer and nanometer levels, which plays a significant role in improving the insulation's thermal performance. Furthermore, the porosity increases from the outer to the middle layer, while decreasing from the middle to the inner layer, contributing to improved thermal insulation and curling properties. The perlite in the inner layer expands during high-temperature use, maintaining close contact between the insulation material and equipment such as pipes. Graphene coated with iron or chromium acts as a far-infrared radiator, inhibiting radiative heat transfer. The binder (polyvinyl alcohol) and dispersant enhance the rheological properties and pore formation of the inner, middle, and outer layers. The composite thermal insulation material with the three-layer structure has excellent thermal insulation performance, especially when used at high temperatures above 600°C, its performance is more outstanding than that of existing thermal insulation materials.

[0026] The second technical solution of the present invention is a low-carbon preparation method of the above-mentioned high-temperature rollable micro-nano multi-level porous inorganic composite thermal insulation material, comprising the following steps:

[0027] (1) Preparation of outer layer slurry: After adding dispersant to water and mixing evenly, add glass fiber and wood cellulose, stir for 10 hours, and fully disperse to obtain mixed slurry. Then add hollow glass beads and binder, continue stirring for 5 to 10 hours, and let it stand for 4 to 6 hours to obtain outer layer slurry.

[0028] (2) Preparation of middle layer slurry: Add dispersant to water and mix well, then add oxide ceramic fiber and stir for 10 hours to fully disperse the mixed slurry. Then add oxide ceramic hollow beads, silica aerogel powder and binder, continue stirring for 5 to 10 hours, and let it stand for 4 to 6 hours to obtain middle layer slurry.

[0029] (3) Preparation of inner layer slurry: After adding the dispersant to water and mixing evenly, add the oxide ceramic fiber and modified graphene, stir for 10 hours, and fully disperse to obtain a mixed slurry. Then add the oxide ceramic hollow beads, perlite and binder, continue stirring for 5 to 10 hours, and let it stand for 4 to 6 hours to obtain the inner layer slurry;

[0030] (4) placing an outer layer of slurry in a centrifugal barrel (made of stainless steel), rotating the centrifugal barrel at a centrifugal linear velocity of 8 to 10 m / s, then decelerating to a centrifugal linear velocity of 4 to 6 m / s, and finally accelerating to a centrifugal linear velocity of 8 to 12 m / s, to obtain an outer layer of thermal insulation material attached to the wall of the centrifugal barrel;

[0031] (5) placing the middle layer slurry in the centrifugal bucket, rotating the bucket at a centrifugal linear velocity of 10 to 12 m / s, then decelerating to a centrifugal linear velocity of 5 to 7 m / s, and finally accelerating to a centrifugal linear velocity of 10 to 14 m / s, and the middle layer adheres to the outer layer;

[0032] (6) placing the inner layer slurry in the centrifugal barrel, rotating the centrifugal barrel at a centrifugal linear velocity of 12 to 14 m / s, then decelerating to a centrifugal linear velocity of 6 to 8 m / s, and finally accelerating to a centrifugal linear velocity of 10 to 14 m / s, and the inner layer adheres to the above-mentioned middle layer;

[0033] (7) The three-layer thermal insulation material obtained in step (6) is naturally dried until the moisture content of the outer layer is 8-12%, and is removed from the centrifugal barrel to obtain the high-temperature rollable micro-nano multi-level porous inorganic composite thermal insulation material (thermal insulation material).

[0034] Furthermore, in steps (4) to (6), the rotation time under each centrifugal linear velocity condition is 10 to 15 minutes.

[0035] The thermal insulation material has a specific water content after being formed, which can make the thermal insulation material have good curling performance.

[0036] Steps (1) to (3) can be performed simultaneously, and the process of segmented dispersion and mixing can achieve the best mixing uniformity of each layer of slurry. After the outer layer slurry is placed in the centrifugal bucket, the centrifugal bucket rotates. Driven by centrifugal force, the outer layer slurry will adhere to the side wall surface of the centrifugal bucket. As the water content in the outer layer slurry decreases, the outer layer slurry can completely adhere to the side wall surface of the centrifugal bucket. The centrifugal linear velocity refers to the speed of the edge of the centrifugal bucket wall. The rotation process of the outer layer slurry in the centrifugal bucket is divided into three stages. The centrifugal linear velocity in the first stage is 8 to 10 m / s, which is for the outer layer slurry to quickly climb along the wall of the centrifugal bucket and basically evenly adhere to the wall of the centrifugal bucket; the centrifugal linear velocity in the second stage is 4 to 6 m / s, and the deceleration is to continue to reduce the water content in the outer layer slurry while making the outer layer gradually dense; the centrifugal linear velocity of the centrifugal bucket in the third stage is increased to 8 to 12 m / s, which is to further reduce the water content of the outer layer and further increase the density of the outer layer. Controlling the centrifugal rotation time at each stage to 10-15 minutes ensures the density of each layer of material and allows sufficient time for the various component particles of different sizes and weights to be evenly distributed during the vibration state rotation. In addition, the centrifugal method can remove a large amount of water during the insulation material preparation process, avoiding the subsequent long drying process, and achieving the goal of low-carbon preparation.

[0037] The insulation material of the present invention is a three-layer structure with varying porosity, achieved through three feeding steps. The outer layer has the most fibers and contains a certain amount of water, giving the material improved curling properties; the middle layer has the highest porosity and forms multi-level micron and nanometer cavities, enhancing thermal insulation performance; and the inner layer improves the material's high-temperature resistance. The insulation material prepared using the method of the present invention can be cut into planar sheets. The diameter and height of the centrifuge bucket determine the length and width of the insulation material; the size of the centrifuge bucket can be selected based on specific requirements.

[0038] The third technical solution of the present invention: an application of the above-mentioned high-temperature rollable micro-nano multi-level porous inorganic composite thermal insulation material in the thermal insulation of high-temperature equipment.

[0039] The present invention discloses the following technical effects:

[0040] (1) The composite thermal insulation material of the present invention has good comprehensive properties, such as fire resistance, low thermal conductivity (small change in thermal conductivity at high temperature), and good flexibility.

[0041] (2) The present invention has determined the component ratio and three-layer structure of the composite thermal insulation material after repeated experiments and tests, and combined with the different particle sizes of multiple components and the modification of the components, the thermal insulation material has excellent thermal insulation performance. The inner layer has good far-infrared radiation performance, reducing radiation heat transfer; the middle layer has excellent heat convection and heat conduction barrier capabilities; and the outer layer has good heat conduction barrier capabilities. In addition, the porosity of the two adjacent layers of materials is controlled so that the porosity of the two adjacent layers of materials has a certain gradient, further increasing the thermal insulation performance of the thermal insulation material. The outer layer of the thermal insulation material has a specific moisture content and high fiber content, which makes the thermal insulation material have excellent curling ability. The inner layer uses high-temperature resistant raw materials, which can be used in high-temperature pipes and equipment of 800-900°C. At the same time, the preparation method of the thermal insulation material of the present invention is simpler in process than the existing technology, which shortens the preparation time, greatly reduces the preparation cost and saves energy, achieving low-carbon preparation. DETAILED DESCRIPTION

[0042] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0043] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0044] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0045] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0046] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0047] The “parts” described in the following examples are all “parts by weight”.

[0048] The centrifugal bucket used in the present invention is made of stainless steel, has a size of φ1000-φ1200 mm, and a height of 450-550 mm.

[0049] Example 1

[0050] A low-carbon preparation method for a high-temperature rollable micro-nano multi-level porous inorganic composite thermal insulation material:

[0051] (1) Preparation of outer layer slurry: 5 parts of dispersant were added to 100 parts of water and mixed evenly, followed by adding 50 parts of glass fiber and 10 parts of wood cellulose, stirring (stirring speed of 10 m / s) for 10 hours to fully disperse the mixed slurry, then adding 30 parts of hollow glass beads and 5 parts of binder, continuing stirring for 8 hours, and allowing to stand for 5 hours to obtain the outer layer slurry;

[0052] The dispersant is composed of a foaming agent (sodium dodecylbenzenesulfonate) and polyborosiloxane in a weight ratio of 3:2;

[0053] The diameter of the glass fiber is 5 to 10 microns and the length is 7 to 9 centimeters;

[0054] The diameter of lignocellulose is 5 to 10 microns and the length is 3 to 5 centimeters;

[0055] The particle size of hollow glass beads is 20 to 50 microns;

[0056] The binder is polyvinyl alcohol.

[0057] (2) Preparation of the middle layer slurry: 5 parts of dispersant were added to 100 parts of water and mixed evenly, followed by adding 30 parts of oxide ceramic fibers and stirring (stirring speed was 12 m / s) for 10 hours to fully disperse the mixed slurry. 50 parts of oxide ceramic hollow beads, 10 parts of silica aerogel powder and 5 parts of binder were then added, and stirring was continued for 8 hours. The mixture was allowed to stand for 5 hours to obtain the middle layer slurry.

[0058] The dispersant is composed of a foaming agent and polyborosiloxane in a weight ratio of 3:2;

[0059] The diameter of oxide ceramic fibers (aluminum silicate fibers) is 5 to 10 microns and the length is 3 to 5 centimeters;

[0060] The particle size of the oxide ceramic hollow beads is 10 to 30 microns; the oxide ceramic hollow beads are composed of silicon oxide hollow microbeads and aluminum oxide hollow microbeads in a weight ratio of 30:20;

[0061] The particle size of the agglomerates of silica aerogel powder is 10 to 50 microns;

[0062] The binder is polyvinyl alcohol.

[0063] (3) Preparation of inner layer slurry: 3 parts of dispersant were added to 100 parts of water and mixed evenly, followed by adding 50 parts of oxide ceramic fiber and 5 parts of modified graphene, stirring (stirring speed was 14 m / s) for 10 hours to fully disperse the mixed slurry, and then adding 30 parts of oxide ceramic hollow beads, 5 parts of perlite and 2 parts of binder, continuing stirring for 10 hours, and letting it stand for 6 hours to obtain the inner layer slurry;

[0064] The dispersant is composed of a foaming agent and polyborosiloxane in a weight ratio of 3:2;

[0065] The diameter of oxide ceramic fibers (alumina fibers) is 5 to 10 microns and the length is 3 to 5 centimeters;

[0066] The modified graphene is graphene coated with chromium on the surface, with a coating thickness of 0.1 μm; the graphene sheet diameter is 10 to 20 μm, and the thickness is 100 to 300 nm;

[0067] The particle size of the oxide ceramic hollow beads is 10 to 30 microns; the oxide ceramic hollow beads are composed of silicon oxide hollow microspheres and aluminum oxide hollow microspheres in a weight ratio of 20:10;

[0068] The size of perlite is 200 mesh;

[0069] The binder is polyvinyl alcohol.

[0070] (4) placing the outer layer slurry in a centrifugal bucket, rotating the bucket at a centrifugal linear velocity of 8 m / s (rotation time of 15 minutes), then decelerating to a centrifugal linear velocity of 4 m / s (rotation time of 15 minutes), and finally accelerating to a centrifugal linear velocity of 8 m / s (rotation time of 15 minutes), to obtain an outer layer of thermal insulation material attached to the wall of the centrifugal bucket;

[0071] (5) The middle layer slurry is placed in the centrifuge bucket, and the centrifuge bucket is rotated at a centrifugal linear velocity of 10 m / s (rotation time is 15 minutes), then decelerated to a centrifugal linear velocity of 5 m / s (rotation time is 15 minutes), and finally accelerated to a centrifugal linear velocity of 10 m / s (rotation time is 15 minutes), and the middle layer is attached to the above outer layer;

[0072] (6) The inner layer slurry is placed in the centrifuge bucket, and the centrifuge bucket is rotated at a centrifugal linear velocity of 12 m / s (rotation time is 15 minutes), then decelerated to a centrifugal linear velocity of 6 m / s (rotation time is 15 minutes), and finally accelerated to a centrifugal linear velocity of 12 m / s (rotation time is 15 minutes), and the inner layer is attached to the above-mentioned middle layer;

[0073] (7) The three-layer thermal insulation material obtained in step (6) is naturally dried until the moisture content of the outer layer is 10%, and is removed from the centrifugal barrel to obtain a high-temperature rollable micro-nano multi-level porous inorganic composite thermal insulation material (thermal insulation material).

[0074] The inner layer porosity of the thermal insulation material prepared in this embodiment is 75%, and the pore size is a few microns to 30 microns (determined by the gaps between the oxide ceramic hollow beads and the oxide ceramic fibers and the particles);

[0075] The middle layer has a porosity of 80% and a pore size of several micrometers to 30 micrometers and 30 nanometers to 50 nanometers (determined by the gaps between silica aerogel powder, oxide ceramic hollow beads and oxide ceramic fibers and particles);

[0076] The porosity of the outer layer is 70%, and the pore size is from a few microns to 50 microns (determined by the gaps between the hollow glass beads and fibers (glass fibers, wood cellulose) and particles).

[0077] The thermal insulation material of this embodiment adopts a three-layer structure. A certain amount of graphene coated with chromium and iron is added to the innermost layer, which can increase the far-infrared radiation capacity, and the emissivity is 0.92. An appropriate amount of silica aerogel powder is added to the middle layer to obtain multi-sized pores from nanometer to micron level, which can greatly reduce heat convection. The room temperature thermal conductivity is as low as 0.036W / mk, and the thermal conductivity at 600℃ is less than 0.088W / mk, which is about half of that of aluminum silicate wool. When the same thermal insulation effect is achieved, the thickness used is only half of that of aluminum silicate wool. The inner layer adopts high-temperature resistant oxide ceramic fibers and oxide ceramic hollow beads, which can make the thermal insulation material of the present invention used for high temperatures of 800-900℃, which is higher than common inorganic thermal insulation materials such as aerogel felt and aluminum silicate wool. The tensile strength of the thermal insulation material prepared by the method of the present invention is 125kPa.

[0078] The present invention combines fibers and hollow microspheres to impart flexibility and strength to the insulation material. Consequently, the insulation material produced using the method has a tensile strength greater than 120 kPa, a thermal conductivity less than 0.04 W / mk at room temperature and less than 0.09 W / mk at 600°C, can be folded up to 90°, and can be repeated 100 times without cracking.

[0079] Comparative Example 1

[0080] Same as Example 1, except that the raw material of the inner layer does not contain oxide ceramic fibers;

[0081] The raw materials of the middle layer do not contain oxide ceramic fibers;

[0082] The outer layer does not contain glass fiber in its raw materials;

[0083] The specific method is as follows:

[0084] (1) Preparation of outer layer slurry: 5 parts of dispersant were added to 100 parts of water and mixed evenly, followed by adding 10 parts of lignocellulose and stirring (stirring speed was 10 m / s) for 10 hours to fully disperse the mixed slurry. 30 parts of hollow glass beads and 5 parts of binder were then added, and stirring was continued for 8 hours. The mixture was allowed to stand for 5 hours to obtain the outer layer slurry.

[0085] The dispersant is composed of a foaming agent (sodium dodecylbenzenesulfonate) and polyborosiloxane in a weight ratio of 3:2;

[0086] The diameter of lignocellulose is 5 to 10 microns and the length is 3 to 5 centimeters;

[0087] The particle size of hollow glass beads is 20 to 50 microns;

[0088] The binder is polyvinyl alcohol.

[0089] (2) Preparation of middle layer slurry: 5 parts of dispersant were added to 100 parts of water, mixed and stirred evenly (stirring speed was 12 m / s) for 10 hours to fully disperse the mixed slurry, and then 50 parts of oxide ceramic hollow beads, 10 parts of silica aerogel powder and 5 parts of binder were added, and stirring was continued for 8 hours. The mixture was allowed to stand for 5 hours to obtain the middle layer slurry;

[0090] The dispersant is composed of a foaming agent and polyborosiloxane in a weight ratio of 3:2;

[0091] The particle size of the oxide ceramic hollow beads is 10 to 30 microns; the oxide ceramic hollow beads are composed of silicon oxide hollow microbeads and aluminum oxide hollow microbeads in a weight ratio of 30:20;

[0092] The particle size of the agglomerates of silica aerogel powder is 10 to 50 microns;

[0093] The binder is polyvinyl alcohol.

[0094] (3) Preparation of inner layer slurry: 3 parts of dispersant were added to 100 parts of water and mixed evenly, followed by adding 5 parts of modified graphene and stirring (stirring speed was 14 m / s) for 10 hours to fully disperse the mixed slurry. Then, 30 parts of oxide ceramic hollow beads, 5 parts of perlite and 2 parts of binder were added, and stirring was continued for 10 hours. The mixture was allowed to stand for 6 hours to obtain the inner layer slurry.

[0095] The dispersant is composed of a foaming agent and polyborosiloxane in a weight ratio of 3:2;

[0096] The modified graphene is graphene coated with chromium on the surface, with a coating thickness of 0.1 μm; the graphene sheet diameter is 10 to 20 μm, and the thickness is 100 to 300 nm;

[0097] The particle size of the oxide ceramic hollow beads is 10 to 30 microns; the oxide ceramic hollow beads are composed of silicon oxide hollow microspheres and aluminum oxide hollow microspheres in a weight ratio of 20:10;

[0098] The size of perlite is 200 mesh;

[0099] The binder is polyvinyl alcohol.

[0100] Steps (4) to (7) are the same as in Example 1.

[0101] The thermal insulation material prepared in this comparative example has poor flexibility and loses its curling property, and is easily cracked and powdered after drying.

[0102] Comparative Example 2

[0103] Same as Example 1, except that the raw material of the inner layer does not contain oxide ceramic hollow beads;

[0104] The raw materials of the middle layer do not contain oxide ceramic hollow beads;

[0105] The outer layer does not contain hollow glass beads;

[0106] The specific preparation method is as follows:

[0107] (1) Preparation of outer layer slurry: 5 parts of dispersant were added to 100 parts of water and mixed evenly, followed by adding 50 parts of glass fiber and 10 parts of wood cellulose, stirring (stirring speed of 10 m / s) for 10 hours to fully disperse the mixed slurry, then adding 5 parts of binder, continuing stirring for 8 hours, and letting it stand for 5 hours to obtain the outer layer slurry;

[0108] The dispersant is composed of a foaming agent (sodium dodecylbenzenesulfonate) and polyborosiloxane in a weight ratio of 3:2;

[0109] The diameter of the glass fiber is 5 to 10 microns and the length is 7 to 9 centimeters;

[0110] The diameter of lignocellulose is 5 to 10 microns and the length is 3 to 5 centimeters;

[0111] The binder is polyvinyl alcohol.

[0112] (2) Preparation of the middle layer slurry: 5 parts of dispersant were added to 100 parts of water and mixed evenly, and then 30 parts of oxide ceramic fiber were added and stirred (stirring speed was 12 m / s) for 10 hours to fully disperse the mixed slurry. Then, 10 parts of silica aerogel powder and 5 parts of binder were added and stirred for 8 hours. The mixture was allowed to stand for 5 hours to obtain the middle layer slurry.

[0113] The dispersant is composed of a foaming agent and polyborosiloxane in a weight ratio of 3:2;

[0114] The diameter of oxide ceramic fibers (aluminum silicate fibers) is 5 to 10 microns and the length is 3 to 5 centimeters;

[0115] The particle size of the agglomerates of silica aerogel powder is 10 to 50 microns;

[0116] The binder is polyvinyl alcohol.

[0117] (3) Preparation of inner layer slurry: 3 parts of dispersant were added to 100 parts of water and mixed evenly, followed by adding 50 parts of oxide ceramic fiber and 5 parts of modified graphene, stirring (stirring speed was 14 m / s) for 10 hours to fully disperse the mixed slurry, and then adding 5 parts of perlite and 2 parts of binder, continuing stirring for 10 hours, and letting it stand for 6 hours to obtain the inner layer slurry;

[0118] The dispersant is composed of a foaming agent and polyborosiloxane in a weight ratio of 3:2;

[0119] The diameter of oxide ceramic fibers (alumina fibers) is 5 to 10 microns and the length is 3 to 5 centimeters;

[0120] The modified graphene is graphene coated with chromium on the surface, with a coating thickness of 0.1 μm; the graphene sheet diameter is 10 to 20 μm, and the thickness is 100 to 300 nm;

[0121] The size of perlite is 200 mesh;

[0122] The binder is polyvinyl alcohol.

[0123] Steps (4) to (7) are the same as in Example 1.

[0124] The thermal insulation material prepared in this comparative example has poor deformation resistance and thermal insulation capacity, is easily compressed and deformed, and has significantly improved high-temperature thermal conductivity, with the thermal conductivity at 600°C being nearly doubled.

[0125] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A high-temperature rollable micro-nano multi-level porous inorganic composite thermal insulation material, characterized in that: The composite thermal insulation material has a three-layer structure of inner, middle and outer layers; The raw materials of the inner layer include, by weight: 50 parts of oxide ceramic fiber, 30 parts of oxide ceramic hollow beads, 5 parts of perlite, 5 parts of modified graphene, 2 parts of binder and 3 parts of dispersant; The raw materials of the middle layer include, by weight: 30 parts of oxide ceramic fibers, 50 parts of oxide ceramic hollow beads, 10 parts of silica aerogel powder, 5 parts of binder and 5 parts of dispersant; The outer layer comprises, by weight, 50 parts of glass fiber, 30 parts of hollow glass beads, 10 parts of wood cellulose, 5 parts of binder and 5 parts of dispersant; The oxide ceramic hollow beads include aluminum oxide hollow microbeads and / or silicon oxide hollow microbeads; The oxide ceramic fibers include one or both of alumina fibers and zirconia fibers; The modified graphene is graphene coated with chromium or iron on the surface, with a coating thickness of 0.1 to 0.2 μm; the graphene sheet diameter is 10 to 20 μm, and the thickness is 100 to 300 nm; The binder includes polyvinyl alcohol; The dispersant is composed of a foaming agent and polyborosiloxane in a weight ratio of 3:2; The glass fiber has a diameter of 5 to 10 microns and a length of 7 to 9 centimeters; The diameters of the wood cellulose and oxide ceramic fibers are both 5 to 10 microns and the lengths are both 3 to 5 centimeters; The particle size of the oxide ceramic hollow beads is 10 to 30 microns; The particle size of the agglomerates of the silica aerogel powder is 10 to 50 microns; The size of the perlite is 200 mesh; The particle size of the hollow glass beads is 20 to 50 microns; The porosity of the composite thermal insulation material increases from the outer layer to the middle layer, and decreases from the middle layer to the inner layer.

2. A low-carbon preparation method for the high-temperature rollable micro-nano multi-level porous inorganic composite thermal insulation material according to claim 1, characterized in that: The following steps are involved: The raw materials of the outer layer, middle layer and inner layer are added into water respectively, dispersed evenly and allowed to stand to obtain outer layer slurry, middle layer slurry and inner layer slurry; The outer layer slurry, the middle layer slurry and the inner layer slurry are sequentially coated on the substrate to obtain the high-temperature curlable micro-nano multi-level porous inorganic composite thermal insulation material.

3. The preparation method according to claim 2, characterized in that The standing time is 4 to 6 hours.

4. The preparation method according to claim 2, characterized in that The coating method includes centrifugal coating; The outer layer slurry coating method specifically includes: rotating at a centrifugal linear velocity of 8 to 10 m / s, then decelerating to 4 to 6 m / s, and finally increasing to 8 to 12 m / s; The coating method of the middle layer slurry specifically comprises: rotating at a centrifugal linear velocity of 10 to 12 m / s, then decelerating to 5 to 7 m / s, and finally increasing to 10 to 14 m / s; The coating method of the inner layer slurry specifically includes: rotating at a centrifugal linear speed of 12 to 14 m / s, then decelerating to 6 to 8 m / s, and finally increasing to 10 to 14 m / s.

5. The preparation method according to claim 4, characterized in that The spinning time at each centrifugal linear speed condition was 10 to 15 minutes.

6. The preparation method according to claim 2, characterized in that The preparation method further comprises: after coating the inner layer slurry, naturally drying the slurry until the moisture content of the outer layer is 8-12%.

7. Use of the high-temperature rollable micro-nano multi-level porous inorganic composite thermal insulation material according to claim 1 in thermal insulation of high-temperature equipment.