Aerogel heat insulation pipe shell and preparation method and application thereof

Abstract

The invention relates to the related field of heat insulation composite material processing, in particular to an aerogel heat insulation pipe shell and a preparation method and application thereof, and the aerogel heat insulation pipe shell is composed of a fiber needled felt without a binder and silicon dioxide aerogel. The manufacturing method comprises the steps of fibrofelt cutting and pre-rolling, sol preparation, rotary dynamic gel forming, supercritical drying, two-end trimming and opening treatment, and the tubular prefabricated part which is accurate in size, convenient and fast to install and capable of replacing aerogel felt is mainly applied to various pipelines and cylindrical equipment needing heat insulation and insulation. Loss of on-site construction materials and consumption of auxiliary materials can be effectively reduced, the construction period is shortened, and the heat insulation engineering quality is improved.

Description

Technical Field

[0001] The present invention relates to the field related to thermal insulation composite material processing, and in particular to an aerogel thermal insulation shell and a preparation method and application thereof. Background Art

[0002] Aerogel materials have been widely used in the fields of petrochemical industry, industrial construction, thermal runaway management, ships, aerospace, etc. due to their excellent thermal insulation performance, wide temperature applicability and long service life. At present, the aerogels used for thermal insulation of pipes and equipment on the market are mainly composite rolls with a thickness of 3-20mm. The construction site adopts the methods of measurement, precise cutting, multi-layer wrapping and forced fixing to meet the thermal insulation requirements of pipes and equipment with different diameters and temperatures. The disadvantages are: (1) the construction process becomes cumbersome and complicated, the construction efficiency is low, and the construction quality is difficult to control; (2) the cutting process causes large material loss, the amount of auxiliary materials used is large, and the labor cost increases exponentially, further pushing up the cost of aerogel projects; (3) there is a lot of dust and scraps on site, the construction environment is poor, and the construction period is long, which is not conducive to the large-scale promotion of aerogel materials.

[0003] The pipes used in insulation projects are generally standard components that can be prefabricated into standard aerogel parts in the factory. Using aerogel shells and tubes for pipe construction allows a single person to complete the shell-and-tube splicing, increasing construction speed by over 300% compared to coil binding. Prefabrication reduces on-site processing. Factory prefabrication of the shells and tubes eliminates errors in on-site coil cutting, reducing material loss from 15% to less than 3%. The longitudinal seams of the outer and inner shells intersect perpendicularly, eliminating the thermal bridge effect caused by overlapping seams in traditional coils and increasing insulation efficiency by over 20%. Maintenance costs are reduced, and the removable design allows for partial replacement, costing only one-fifth the cost of replacing the entire coil, extending its service life to over 20 years. Precise dimensions facilitate standardized appearance management, meeting the safety and visual management requirements of some industrial sectors.

[0004] Patent CN106589436A discloses a method for preparing nanoporous aerogel composite tubes and shells. Fibers and resins are shaped at 180-200°C to form a prefabricated cotton tube. The prefabricated cotton tube is then impregnated with a solution, gelled, aged, and then supercritically dried with carbon dioxide to form an aerogel composite tube and shell. Patent CN 113334868A discloses a multilayer aerogel composite material and its preparation method. Aerogel coils are bonded with a binder and cured to form an aerogel tube or sheet. The presence of large amounts of organic matter, such as resin and binder, significantly impacts the thermal insulation, combustion performance, high-temperature stability, hygroscopicity, service life, and environmental performance of the aerogel tube and shell, resulting in a reduction in overall performance compared to similar aerogel coils. Summary of the Invention

[0005] Therefore, the present invention provides an aerogel insulation shell and tube and its preparation method and application to solve the above technical problems.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: an aerogel insulation shell, which is composed of fiber needle felt without binder and silica aerogel.

[0007] Preferably, the wall thickness of the aerogel insulation shell is in the range of 2-100 mm.

[0008] Preferably, the density of the aerogel insulation shell is 100-200 kg / m 3 , hydrophobicity greater than 99%, combustion grade A (A1), full immersion mass water absorption less than 3%, thermal conductivity less than

[0009] 0.021W / (m·K).

[0010] Preferably, the fiber needle felt is an inorganic fiber needle felt, which is a composite of one or more of glass fiber needle felt, basalt fiber needle felt, high silica fiber, and ceramic fiber needle felt.

[0011] Preferably, the fiber needle felt has a thickness of 2-10 mm, preferably 3-6 mm.

[0012] Preferably, the density of the fiber needle felt is not greater than 140 kg / m 3 , preferably 80-110kg / m 3 .

[0013] The present invention provides a method for preparing an aerogel thermal insulation shell and tube, comprising the following steps:

[0014] S1. Fiber Felt Cutting and Pre-rolling: Calculate the required fiber needle felt length according to the inner diameter of the tube shell and the predetermined thickness, cut the required length using a cutting machine, and neatly wind the fiber needle felt on the mold tube;

[0015] S2. Preparation of sol: Prepare ethoxylated silicate, ethanol and water in a molar ratio of 1:

[0016] (3-18): (3-5) was mixed evenly, acid was added to adjust the pH to 3-6, and the mixture was hydrolyzed for more than 4 hours to obtain silica sol, which was set aside;

[0017] S3. Adjust the pH of the silica sol in step S2 to 7.0-8.5 with liquid caustic soda to obtain a silica sol with a gel time of 5-30 minutes. Immerse the wound fiber tube in step S1 in the silica sol to saturate the sol and then place it on a tube shell coiling machine. Rotate and limit the thickness of the tube shell using a rotary dynamic gel forming technology until the sol is transformed into a naturally non-deformable gel tube shell. Then, pull out the central mold tube to form a wet gel tube shell.

[0018] S4, then transferring the wet gel tube shell to a material barrel, adding ethanol to soak, and then transferring to an ethanol supercritical drying kettle for drying, and trimming both ends to obtain the aerogel insulation tube shell of the present invention;

[0019] S5. To facilitate installation, the aerogel insulation shell in step S4 may be cut and opened.

[0020] Preferably, the ethoxy-containing silicate in step S2 is a mixture of tetraethoxysilane and methyltriethoxysilane in a molar ratio of 10:(1-4).

[0021] The invention discloses an aerogel thermal insulation shell prepared by a preparation method, which is used in tubular prefabricated parts with precise and controllable dimensions and can efficiently replace aerogel coils. The aerogel thermal insulation shell is mainly used in various pipelines and cylindrical equipment requiring thermal insulation, and can effectively reduce the loss of on-site construction materials and the consumption of auxiliary materials, shorten the construction period, and improve the quality of thermal insulation projects. The aerogel thermal insulation shell is mainly used in the thermal insulation and protection of petrochemical pipelines, thermal pipe networks, ship power pipelines, etc.

[0022] Beneficial effects of the present invention:

[0023] 1. The aerogel tube shell of the present invention is prepared by in-situ molding of inorganic fiber needle-punched felt and aerogel, without adding any organic resin or adhesive, flame retardant or other additives. The comprehensive properties of the obtained aerogel tube shell, such as heat insulation, temperature resistance, hydrophobicity, and combustion, are the same as those of similar aerogel coils.

[0024] 2. The present invention uses the rotary dynamic gel molding technology to ensure the thickness uniformity and roundness of the tube shell, and the molding effect is better.

[0025] 3. The present invention uses ethanol supercritical drying to dry the gel, and the drying medium is consistent with the medium in the gel pores, ensuring the consistency of product strength and performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a photo of a ceramic fiber reinforced aerogel shell prepared by the preparation method of the present invention;

[0027] Figure 2 This is a physical picture of the glass fiber reinforced aerogel shell prepared by the preparation method of the present invention. DETAILED DESCRIPTION

[0028] In order to further explain the technical solution of the present invention, it is described in detail below through specific embodiments.

[0029] Example 1

[0030] The present invention provides an aerogel thermal insulation shell and a preparation method thereof, comprising the following steps:

[0031] S1. Cut 1130 mm of ceramic needle felt with a thickness of 6 mm and wind it on a mold tube with an outer diameter of 73 mm for later use. No adhesive is required during the winding process.

[0032] S2. Preparation of sol: Ethyl orthosilicate, ethanol, and water were mixed in a molar ratio of 1:15:3, 10% hydrochloric acid was added, the pH value was adjusted to 3-6, and the mixture was stirred for 4 hours to obtain silica sol;

[0033] S3, using 1% liquid alkali ethanol solution, adjust the pH of S2 silica sol to 7.0-8.5 to obtain silica sol with a gel time of about 20 minutes, soak the ceramic fiber felt wound on the mold tube in S1 in the silica sol, and after saturated with the sol, place it on the tube and shell coiling machine, rotate and limit the thickness at a speed of 80r / min along the direction of the fiber felt winding the tube, and use the rotary dynamic gel molding technology until the sol is transformed into a gel tube shell that does not deform in its natural state. Then, the central mold tube can be pulled out to form a wet gel ceramic fiber composite tube shell;

[0034] S4. The wet gel ceramic fiber composite tube shell is transferred to a material barrel, soaked in ethanol, and then transferred to an ethanol supercritical drying kettle. After drying at a temperature and pressure of 270°C / 11.0MPa, drying and cooling, the two ends of the tube shell are cut flush to obtain the aerogel insulation tube shell of the present invention.

[0035] According to the above steps, a ceramic fiber aerogel insulation shell with an inner diameter of 73mm and a wall thickness of 23mm can be obtained, and its density is 188kg / m 3 , hydrophobicity 99.1%, full immersion mass water absorption rate 0.5%, thermal conductivity 0.020W / (m·K), with excellent comprehensive performance.

[0036] Example 2

[0037] The present invention provides an aerogel thermal insulation shell and a preparation method thereof, comprising the following steps:

[0038] S1. Cut the glass fiber needle felt with a thickness of 3 mm into 1190 mm, 1365 mm, 1350 mm, 1740 mm, 2100 mm, 2290 mm, and 2520 mm, and then wind them on mold tubes with outer diameters of 22 mm, 27 mm, 34 mm, 61 mm, 73 mm, and 89 mm, respectively, for use;

[0039] S2. Preparation of sol: (ethyl orthosilicate / methyltriethoxysilane), ethanol, and water were mixed in a molar ratio of (0.7:0.3):15:3, 10% hydrochloric acid was added, the pH value was adjusted to 5.5, and the mixture was stirred for 4 hours to obtain silica sol;

[0040] S3, using 1% liquid alkali ethanol solution, adjust the pH of S2 silica sol to 7.0-8.5 to obtain silica sol with a gel time of about 20 minutes, and soak the glass fiber needle-punched felt wound on 7 kinds of mold tubes with S1 in the silica sol. After saturated with the sol, it is placed on a tube and shell coiling machine and rotated and limited in thickness at a speed of 80r / min along the direction of the fiber felt winding around the tube. Through the rotation dynamic gel molding technology, until the sol is transformed into a gel tube shell that does not deform in its natural state, the central mold tube can be pulled out to form a wet gel glass fiber composite tube shell;

[0041] S4. The wet gel glass fiber composite tube shell is transferred to a material barrel, soaked in ethanol, and then transferred to an ethanol supercritical drying kettle. After drying at a temperature and pressure of 265°C / 10.0MPa, drying and cooling, the two ends of the tube shell are cut flush to obtain the aerogel insulation tube shell of the present invention.

[0042] According to the preparation method of the above steps, glass fiber aerogel insulation shells with inner diameters of 22 mm, 27 mm, 34 mm, 61 mm, 73 mm, and 89 mm and wall thicknesses of 23 mm, 25 mm, 24 mm, 23 mm, 25 mm, 25 mm, and 22 mm can be obtained in sequence. The density is 160-180 mm, the hydrophobicity is 99.1%, the fully immersed mass water absorption rate is 0.5%, and the thermal conductivity coefficient is 0.020 W / (m·K), which has excellent comprehensive performance.

[0043] The invention discloses an aerogel thermal insulation shell prepared by a method for preparing an aerogel thermal insulation shell. According to the national standard GB10294-2008, the thermal conductivity at 25° C. is 0.021 W / K·m, and the volume density is 160-180 kg / m 3 .

[0044] The present invention provides an aerogel thermal insulation shell and a preparation method and application thereof. The aerogel shell is prepared by in-situ molding of inorganic fiber needle felt and aerogel, without adding any organic resin or adhesive, flame retardant or other auxiliary agents. The obtained aerogel shell has the same comprehensive properties as similar aerogel coils, such as thermal insulation, temperature resistance, hydrophobicity, and combustion. The rotary dynamic gel molding technology is used to ensure the thickness uniformity and roundness of the shell, and the molding effect is better. The gel is dried by ethanol supercritical drying, and the drying medium is consistent with the medium in the gel pores, thereby ensuring the consistency of the strength and performance of the product.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An aerogel insulated shell and tube, characterized by: The aerogel thermal insulation shell is composed of fiber needle felt without binder and silicon dioxide aerogel.

2. The aerogel insulated shell and tube according to claim 1, characterized in that: The wall thickness of the aerogel insulation shell is in the range of 2-100 mm.

3. The aerogel insulated shell and tube according to claim 2, characterized in that: The density of the aerogel insulation shell is 100-200 kg / m 3 , hydrophobicity greater than 99%, combustion grade A (A1), full immersion mass water absorption less than 3%, thermal conductivity less than 0.021W / (m·K).

4. The aerogel insulated tube shell according to claim 1, characterized in that: The fiber needle felt is an inorganic fiber needle felt, which is a composite of one or more of glass fiber needle felt, basalt fiber needle felt, high silica fiber, and ceramic fiber needle felt.

5. The aerogel insulated tube shell according to claim 4, characterized in that: The fiber needle felt has a thickness of 2-10 mm.

6. The aerogel insulated tube shell according to claim 5, characterized in that: The density of the fiber needle felt is not more than 140 kg / m 3 .

7. A method for preparing an aerogel insulated tube shell, according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Fiber Felt Cutting and Pre-rolling: Calculate the required fiber needle felt length according to the inner diameter of the tube shell and the predetermined thickness, cut the required length using a cutting machine, and neatly wind the fiber needle felt on the mold tube; S2. Preparation of sol: Prepare ethoxylated silicate, ethanol and water in a molar ratio of 1: (3-18): (3-5) was mixed evenly, acid was added to adjust the pH to 3-6, and the mixture was hydrolyzed for more than 4 hours to obtain silica sol, which was set aside; S3. Adjust the pH of the silica sol in step S2 to 7.0-8.5 with liquid caustic soda to obtain a silica sol with a gel time of 5-30 minutes. Immerse the wound fiber tube in step S1 in the silica sol to saturate the sol and then place it on a tube shell coiling machine. Rotate and limit the thickness of the tube shell using a rotary dynamic gel forming technology until the sol is transformed into a naturally non-deformable gel tube shell. Then, pull out the central mold tube to form a wet gel tube shell. S4, then transferring the wet gel tube shell to a material barrel, adding ethanol to soak, and then transferring to an ethanol supercritical drying kettle for drying, and trimming both ends to obtain the aerogel insulation tube shell of the present invention; S5. To facilitate installation, the aerogel insulation shell in step S4 may be cut and opened.

8. The method for preparing an aerogel insulation shell and tube according to claim 7, characterized in that: In step S2, the ethoxy-containing silicate is a mixture of tetraethoxysilane and methyltriethoxysilane, with a molar ratio of 10:(1-4).

9. Use of an aerogel thermal insulation shell prepared according to the method for preparing an aerogel thermal insulation shell according to claim 7 in a tubular preform replacing an aerogel coil.

Images