Preparation method of large-pipe-diameter thermal insulation pipeline

Abstract

The invention discloses a preparation method of a large-pipe-diameter heat preservation pipeline, and relates to the technical field of heat preservation pipelines, and the preparation method comprises the steps of material selection, pipeline forming and surface treatment, heat preservation material preparation and large-pipe-diameter heat preservation pipeline preparation. According to the invention, the coal ash, the blast furnace slag or the desulfurized fly ash are used as the admixture, different proportions are selected according to different use environments, the large-pipe-diameter thermal insulation pipeline using the rock wool coiled material as the thermal insulation material is prepared, the addition amount of basalt can be effectively reduced, the cost is reduced, and the blast furnace slag can provide certain cohesiveness and porosity, so that the thermal insulation performance of the pipeline is improved. Meanwhile, industrial by-products are adopted, waste utilization is achieved, waste reduction and environmental influence reduction are facilitated, when the heat preservation material is prepared, inert gas is introduced in the melting process, VOCs can be effectively inhibited from being generated, and through the performance of the rock wool coiled material, the heat preservation effect is improved. And the heat preservation capacity and the compressive strength of the large-pipe-diameter heat preservation pipeline are improved.

Description

Technical Field

[0001] The invention relates to the technical field of thermal insulation pipes, and in particular to a method for preparing a large-diameter thermal insulation pipe. Background Art

[0002] With the development of industry, the demand for heat energy transportation is increasing, and the use of large-diameter insulated pipes is becoming more and more common. Insulated pipes are the abbreviation of insulated pipes, which are used for the transportation of liquids, gases and other media and have the functions of heat preservation and cold insulation.

[0003] The Chinese patent application with announcement number CN117024037A discloses an anti-corrosion and heat-insulating material for oil pipelines and its preparation process, which comprises: (1) laying modified basalt fibers flat and spraying modified binders and waterproofing agents thereon, and then laying modified basalt fibers flat on them and repeating the above spraying to obtain an intermediate anti-corrosion and heat-insulating material; (2) compressing the intermediate anti-corrosion and heat-insulating material and placing it in a dryer for drying and solidification to obtain the anti-corrosion and heat-insulating material. The present invention sprays an aqueous sodium silicate solution on the basalt fibers, and SiO4 tetrahedrons and AlO4 tetrahedrons are dissociated on the surface of the basalt fibers. Then, a hydrogen peroxide solution is sprayed on the fibers, which decomposes under alkaline conditions to produce O2. The SiO4 tetrahedrons and AlO4 tetrahedrons are connected by sharing O bridges, and polymerization reactions occur to form oligomers. Under the impact of O2, gaps are formed on the fiber surface and the oligomers, thereby improving the thermal insulation performance and connection strength of the rock wool material. The preparation method in the above patent uses rock wool as the thermal insulation material, but a large amount of basalt is required as raw material in the preparation process of rock wool, which is too costly. In addition, volatile organic compounds (VOCs) are generated in the preparation process. VOCs may cause the pore structure in the rock wool to be unstable, affecting its thermal insulation performance and compressive strength. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a large-diameter insulated pipe, which solves the problem that the existing insulated pipe has high cost during the preparation process, volatile organic compounds (VOCs) are generated during the preparation of the insulation material, resulting in unstable pore structure in the rock wool, affecting its insulation performance and compressive strength.

[0005] The present invention solves the above technical problems through the following technical solutions, a method for preparing a large-diameter thermal insulation pipe, including material selection, pipe forming and surface treatment, thermal insulation material preparation and large-diameter thermal insulation pipe preparation, specifically comprising the following steps: Step 1: Material selection: Select pipe materials and insulation materials with excellent thermal stability and corrosion resistance; Step 2: Pipe forming and surface treatment: Select carbon steel, stainless steel or high-density polyethylene as the pipe material, and manufacture the selected material into a pipe of the required diameter and length through conventional welding, extrusion or molding processes; Step 3: Preparation of thermal insulation materials: rock wool is selected as the thermal insulation material, basalt ore is selected as the raw material, fly ash, blast furnace slag or desulfurized ash is selected as the admixture, adhesive and other additives are matched, inert gas is introduced during the melting process, and the rock wool coil is prepared; Step 4: Preparation of large diameter insulated pipes: Wrap the rock wool roll on the pipe, fix it with adhesive, cover the rock wool-coated pipe with waterproof and weather-resistant material, and test whether the insulation performance meets the standards.

[0006] Preferably, the admixture is fly ash, the weight of the basalt is 70%, the weight of the fly ash is 20%, the weight of the adhesive is 5%, and the weight of other additives is 5%. The preparation of the thermal insulation material in step three specifically includes the following steps: Step S1: Raw material preparation: crushing and grinding basalt to a particle size of 200-500 mesh, collecting and sieving fly ash, using phenolic resin as a binder, and using waterproofing agent and fire retardant as other additives; Step S2: preparing inert gas: selecting nitrogen or helium as the inert gas; Step S3: Mixing: according to the proportion, the prepared basalt, fly ash, phenolic resin, waterproofing agent and fire retardant are put into a mixer for dry mixing; Step S4: high temperature melting: the mixture is transferred to a melting furnace, an inert gas is introduced into the melting furnace, and the melting temperature is set between 1400° C. and 1600° C.; Step S5: Fiberization: Using a fiberization device to process the molten mixture into fine rock wool fibers, cooling the molten liquid and rapidly solidifying it through a centrifugal and blowing process to form fine rock wool fibers, and maintaining the injection of inert gas during solidification; Step S6: Molding: Collect and compact the rock wool fibers to form a rock wool coil of desired thickness and density.

[0007] Preferably, the admixture is blast furnace slag, the weight of the basalt is 60%, the weight of the blast furnace slag is 30%, the weight of the adhesive is 5%, and the weight of other additives is 5%. The preparation of the thermal insulation material in step three specifically includes the following steps: Step N1: Raw material preparation: crushing and grinding basalt to 200-500 mesh, collecting and screening blast furnace slag, phenolic resin as adhesive, waterproofing agent and fire retardant as other additives; Step N2: Inert gas preparation: nitrogen or helium is selected as the inert gas; Step N3: Mixing: according to the proportion, put the prepared basalt, blast furnace slag, phenolic resin, waterproofing agent and fire retardant into a mixer for dry mixing; Step N4: high temperature melting: the mixture is transferred to a melting furnace, an inert gas is introduced into the melting furnace, and the melting temperature is set between 1400° C. and 1600° C.; Step N5: Fiberization: Use a fiberization device to process the molten mixture into fine rock wool fibers, and cool and rapidly solidify the molten liquid through centrifugal and blowing processes to form fine rock wool fibers, and keep the injection of inert gas during solidification; Step N6: Molding: Collect and compact the rock wool fibers to form a rock wool roll of desired thickness and density.

[0008] Preferably, the admixture is desulfurized ash, the weight of the basalt is 60%, the weight of the desulfurized ash is 30%, the weight of the adhesive is 5%, and the weight of other additives is 5%. The preparation of the thermal insulation material in step three specifically includes the following steps: Step M1: Raw material preparation: crush and grind the basalt to a particle size of 200-500 mesh, collect and screen the desulfurized ash, use phenolic resin as a binder, and use waterproofing agent and fire retardant as other additives; Step M2: Inert gas preparation: nitrogen or helium is selected as the inert gas; Step M3: Mixing: according to the proportion, put the prepared basalt, desulfurized ash, phenolic resin, waterproofing agent and fire retardant into a mixer for dry mixing; Step M4: high temperature melting: the mixture is transferred to a melting furnace, an inert gas is introduced into the melting furnace, and the melting temperature is set between 1400° C. and 1600° C.; Step M5: Fiberization: Use fiberization equipment to process the molten mixture into filamentous rock wool fibers, and cool and rapidly solidify the molten liquid through centrifugal and blowing processes to form fine rock wool fibers, and keep the injection of inert gas during solidification; Step M6: Molding: Collect and compact the rock wool fibers to form a rock wool coil of desired thickness and density.

[0009] Preferably, the waterproof and weather-resistant material in step 4 is specifically PE, aluminum foil or galvanized steel plate.

[0010] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention uses fly ash, blast furnace slag or desulfurized ash as admixtures, selects different proportions according to different use environments, and prepares large-diameter insulated pipes with rock wool coils as insulation materials, which can effectively reduce the amount of basalt added and reduce costs. The blast furnace slag can provide certain adhesion and porosity, thereby improving the performance of the large-diameter insulated pipes. At the same time, industrial by-products are used to realize waste utilization, which helps to reduce waste and reduce environmental impact, and is in line with the goals of sustainable development and resource recycling.

[0011] 2. The present invention can effectively suppress the generation of VOCs by introducing inert gas during the melting process when preparing the thermal insulation material, and improve the thermal insulation capacity and compressive strength of large-diameter thermal insulation pipes through the performance of rock wool coils, thereby improving the performance of large-diameter thermal insulation pipes. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the preparation process of the present invention; Figure 2 It is a schematic diagram of the process of preparing the thermal insulation material in the present invention. DETAILED DESCRIPTION

[0013] The release of VOCs may form bubbles during the cooling process of rock wool. If these bubbles are not released in time, it may lead to uneven distribution of pores or excessively large pores, affecting the stability of the pore structure. Large pores or uneven distribution of bubbles will cause the density of rock wool to decrease and form loose materials. The release of VOCs causes the formation of bubbles, which will change the fluidity of air inside the rock wool and affect its thermal insulation performance. If the air does not flow smoothly inside the material, it will increase the conduction of heat, thereby reducing the thermal insulation performance; The instability of the pore structure may cause defects in the material when it is under pressure. Such defects will cause stress concentration during loading, resulting in a decrease in the compressive strength of the rock wool.

[0014] Fly ash is the ash emitted from coal-fired power plants and contains a large amount of silicates and aluminates; Desulfurization ash is a byproduct of the desulfurization process in coal-fired power plants, which usually contains gypsum and other components; Blast furnace slag is a by-product produced in the steel smelting process, mainly containing calcium, aluminum, silicon and iron.

[0015] The above and other technical features and advantages of the present invention are described in more detail below in conjunction with the accompanying drawings.

[0016] A method for preparing a large diameter heat-insulated pipe, such as Figure 1-Figure 2 As shown, it includes material selection, pipeline forming and surface treatment, insulation material preparation and large diameter insulation pipeline preparation, which specifically includes the following steps: Step 1: Material selection: Select pipe materials and insulation materials with excellent thermal stability and corrosion resistance; Step 2: Pipe forming and surface treatment: Select carbon steel, stainless steel or high-density polyethylene as the pipe material, and manufacture the selected material into a pipe of the required diameter and length through conventional welding, extrusion or molding processes; Step 3: Preparation of thermal insulation materials: rock wool is selected as the thermal insulation material, basalt ore is selected as the raw material, fly ash, blast furnace slag or desulfurized ash is selected as the admixture, adhesive and other additives are matched, inert gas is introduced during the melting process, and the rock wool coil is prepared; Step 4: Preparation of large diameter insulated pipes: Wrap the rock wool roll on the pipe, fix it with adhesive, cover the rock wool-coated pipe with waterproof and weather-resistant material, and test whether the insulation performance meets the standards.

[0017] Furthermore, the waterproof and weather-resistant material in step 4 is specifically PE, aluminum foil or galvanized steel plate, which is cold-stuck (such as PE film) or heat-sealed (such as aluminum foil) on the surface of the rock wool to form a closed protective layer, and mechanical fixing (such as bolts, clamps) or welding methods are used to ensure that it is not damaged or falls off during long-term use.

[0018] Embodiment 1

[0019] This embodiment provides a technical solution: the admixture is specifically fly ash, basalt accounts for 70% by weight, fly ash accounts for 20% by weight, adhesive accounts for 5% by weight, and other additives account for 5% by weight. The preparation of the thermal insulation material in step three specifically includes the following steps: Step S1: Raw material preparation: crushing and grinding basalt to a particle size of 200-500 mesh, collecting and sieving fly ash, using phenolic resin as a binder, and using waterproofing agent and fire retardant as other additives; Step S2: preparing inert gas: selecting nitrogen or helium as the inert gas; Step S3: Mixing: according to the proportion, the prepared basalt, fly ash, phenolic resin, waterproofing agent and fire retardant are put into a mixer for dry mixing; Step S4: high temperature melting: the mixture is transferred to a melting furnace, an inert gas is introduced into the melting furnace, and the melting temperature is set between 1400° C. and 1600° C.; Step S5: Fiberization: Using a fiberization device to process the molten mixture into fine rock wool fibers, cooling the molten liquid and rapidly solidifying it through a centrifugal and blowing process to form fine rock wool fibers, and maintaining the injection of inert gas during solidification; Step S6: Molding: Collect and compact the rock wool fibers to form a rock wool coil of desired thickness and density.

[0020] Embodiment 2

[0021] This embodiment provides a technical solution: the admixture is specifically blast furnace slag, basalt accounts for 60% by weight, blast furnace slag accounts for 30% by weight, adhesive accounts for 5% by weight, and other additives account for 5% by weight. The preparation of the thermal insulation material in step three specifically includes the following steps: Step N1: Raw material preparation: crushing and grinding basalt to 200-500 mesh, collecting and screening blast furnace slag, phenolic resin as adhesive, waterproofing agent and fire retardant as other additives; Step N2: Inert gas preparation: nitrogen or helium is selected as the inert gas; Step N3: Mixing: according to the proportion, put the prepared basalt, blast furnace slag, phenolic resin, waterproofing agent and fire retardant into a mixer for dry mixing; Step N4: high temperature melting: the mixture is transferred to a melting furnace, an inert gas is introduced into the melting furnace, and the melting temperature is set between 1400° C. and 1600° C.; Step N5: Fiberization: Use a fiberization device to process the molten mixture into fine rock wool fibers, and cool and rapidly solidify the molten liquid through centrifugal and blowing processes to form fine rock wool fibers, and keep the injection of inert gas during solidification; Step N6: Molding: Collect and compact the rock wool fibers to form a rock wool roll of desired thickness and density.

[0022] Embodiment 3

[0023] This embodiment provides a technical solution: the admixture is specifically desulfurized ash, the weight of basalt accounts for 60%, the weight of desulfurized ash accounts for 30%, the weight of adhesive accounts for 5%, and the weight of other additives accounts for 5%. The preparation of the thermal insulation material in step three specifically includes the following steps: Step M1: Raw material preparation: crush and grind the basalt to a particle size of 200-500 mesh, collect and screen the desulfurized ash, use phenolic resin as a binder, and use waterproofing agent and fire retardant as other additives; Step M2: Inert gas preparation: nitrogen or helium is selected as the inert gas; Step M3: Mixing: according to the proportion, put the prepared basalt, desulfurized ash, phenolic resin, waterproofing agent and fire retardant into a mixer for dry mixing; Step M4: high temperature melting: the mixture is transferred to a melting furnace, an inert gas is introduced into the melting furnace, and the melting temperature is set between 1400° C. and 1600° C.; Step M5: Fiberization: Use fiberization equipment to process the molten mixture into filamentous rock wool fibers, and cool and rapidly solidify the molten liquid through centrifugal and blowing processes to form fine rock wool fibers, and keep the injection of inert gas during solidification; Step M6: Molding: Collect and compact the rock wool fibers to form a rock wool coil of desired thickness and density.

[0024] Embodiment 4

[0025] This embodiment provides a technical solution: the admixture is specifically a mixture of fly ash and blast furnace slag, the weight of basalt accounts for 50%, the weight of fly ash accounts for 15%, the weight of blast furnace slag accounts for 15%, the weight of adhesive accounts for 5%, and the weight of other additives accounts for 5%. The preparation of the thermal insulation material in step three specifically includes the following steps: Step M1: Raw material preparation: crushing and grinding basalt to 200-500 mesh, collecting and screening fly ash and blast furnace slag, phenolic resin as adhesive, waterproofing agent and fire retardant as other additives; Step M2: Inert gas preparation: nitrogen or helium is selected as the inert gas; Step M3: Mixing: according to the proportion, put the prepared basalt, fly ash, blast furnace slag, phenolic resin, waterproofing agent and fire retardant into a mixer for dry mixing; Step M4: high temperature melting: the mixture is transferred to a melting furnace, an inert gas is introduced into the melting furnace, and the melting temperature is set between 1400° C. and 1600° C.; Step M5: Fiberization: Use fiberization equipment to process the molten mixture into filamentous rock wool fibers, and cool and rapidly solidify the molten liquid through centrifugal and blowing processes to form fine rock wool fibers, and keep the injection of inert gas during solidification; Step M6: Molding: Collect and compact the rock wool fibers to form a rock wool coil of desired thickness and density.

[0026] Embodiment 5

[0027] This embodiment provides a technical solution: the admixture is specifically a mixture of fly ash and desulfurized ash, the weight of basalt accounts for 60%, the weight of fly ash accounts for 15%, the weight of desulfurized ash accounts for 15%, the weight of adhesive accounts for 5%, and the weight of other additives accounts for 5%. The preparation of the thermal insulation material in step three specifically includes the following steps: Step M1: Raw material preparation: crush and grind basalt to 200-500 mesh, collect and screen fly ash and desulfurization ash, use phenolic resin as adhesive, and waterproofing agent and fire retardant as other additives; Step M2: Inert gas preparation: nitrogen or helium is selected as the inert gas; Step M3: Mixing: according to the proportion, put the prepared basalt, fly ash, desulfurized ash, phenolic resin, waterproofing agent and fire retardant into a mixer for dry mixing; Step M4: high temperature melting: the mixture is transferred to a melting furnace, an inert gas is introduced into the melting furnace, and the melting temperature is set between 1400° C. and 1600° C.; Step M5: Fiberization: Use fiberization equipment to process the molten mixture into filamentous rock wool fibers, and cool and rapidly solidify the molten liquid through centrifugal and blowing processes to form fine rock wool fibers, and keep the injection of inert gas during solidification; Step M6: Molding: Collect and compact the rock wool fibers to form a rock wool coil of desired thickness and density.

[0028] Embodiment 6

[0029] This embodiment provides a technical solution: the admixture is specifically a mixture of blast furnace slag and desulfurized ash, the weight of basalt accounts for 60%, the weight of blast furnace slag accounts for 15%, the weight of desulfurized ash accounts for 15%, the weight of adhesive accounts for 5%, and the weight of other additives accounts for 5%. The preparation of the thermal insulation material in step three specifically includes the following steps: Step M1: Raw material preparation: crush and grind basalt to 200-500 mesh, collect and screen blast furnace slag and desulfurization ash, use phenolic resin as adhesive, and waterproofing agent and fire retardant as other additives; Step M2: Inert gas preparation: nitrogen or helium is selected as the inert gas; Step M3: Mixing: according to the proportion, put the prepared basalt, blast furnace slag, desulfurized ash, phenolic resin, waterproofing agent and fire retardant into a mixer for dry mixing; Step M4: high temperature melting: the mixture is transferred to a melting furnace, an inert gas is introduced into the melting furnace, and the melting temperature is set between 1400° C. and 1600° C.; Step M5: Fiberization: Use fiberization equipment to process the molten mixture into filamentous rock wool fibers, and cool and rapidly solidify the molten liquid through centrifugal and blowing processes to form fine rock wool fibers, and keep the injection of inert gas during solidification; Step M6: Molding: Collect and compact the rock wool fibers to form a rock wool coil of desired thickness and density.

[0030] Embodiment 7

[0031] This embodiment provides a technical solution: the admixture is specifically a mixture of fly ash, blast furnace slag and desulfurized ash, the weight of basalt accounts for 60%, the weight of fly ash accounts for 10%, the weight of blast furnace slag accounts for 10%, the weight of desulfurized ash accounts for 10%, the weight of adhesive accounts for 5%, and the weight of other additives accounts for 5%. The preparation of the thermal insulation material in step three specifically includes the following steps: Step M1: Raw material preparation: crush and grind basalt to 200-500 mesh, collect and screen fly ash, blast furnace slag and desulfurization ash, use phenolic resin as adhesive, and waterproofing agent and fire retardant as other additives; Step M2: Inert gas preparation: nitrogen or helium is selected as the inert gas; Step M3: Mixing: according to the proportion, put the prepared basalt, fly ash, blast furnace slag, desulfurization ash, phenolic resin, waterproofing agent and fire retardant into a mixer for dry mixing; Step M4: high temperature melting: the mixture is transferred to a melting furnace, an inert gas is introduced into the melting furnace, and the melting temperature is set between 1400° C. and 1600° C.; Step M5: Fiberization: Use fiberization equipment to process the molten mixture into filamentous rock wool fibers, and cool and rapidly solidify the molten liquid through centrifugal and blowing processes to form fine rock wool fibers, and keep the injection of inert gas during solidification; Step M6: Molding: Collect and compact the rock wool fibers to form a rock wool coil of desired thickness and density.

[0032] Embodiment 8

[0033] This embodiment provides a technical solution: basalt accounts for 90% by weight, adhesive accounts for 5% by weight, and other additives account for 5% by weight. The preparation of the thermal insulation material in step three specifically includes the following steps: Step M1: Raw material preparation: crush and grind the basalt to a particle size of 200-500 mesh, use phenolic resin as a binder, and waterproofing agent and fire retardant as other additives; Step M2: Inert gas preparation: nitrogen or helium is selected as the inert gas; Step M3: Mixing: according to the proportion, put the prepared basalt, phenolic resin, waterproofing agent and fire retardant into a mixer for dry mixing; Step M4: high temperature melting: the mixture is transferred to a melting furnace, an inert gas is introduced into the melting furnace, and the melting temperature is set between 1400° C. and 1600° C.; Step M5: Fiberization: Use fiberization equipment to process the molten mixture into filamentous rock wool fibers, and cool and rapidly solidify the molten liquid through centrifugal and blowing processes to form fine rock wool fibers, and keep the injection of inert gas during solidification; Step M6: Molding: Collect and compact the rock wool fibers to form a rock wool coil of desired thickness and density.

[0034] Take equal amounts of the rock wool coil obtained in Example 1, the rock wool coil obtained in Example 2, the rock wool coil obtained in Example 3, the rock wool coil obtained in Example 4, the rock wool coil obtained in Example 5, the rock wool coil obtained in Example 6, the rock wool coil obtained in Example 7 and the rock wool coil obtained in Example 8, and test the thermal insulation performance of the prepared large-diameter insulated pipes, and test the thermal conductivity, density and compressive strength thereof to obtain the following table: Standard requirements: comply with relevant national and industry standards, such as GB / T 11835-2007 "Technical Specifications for Insulated Pipes";

[0035] As can be seen from Table 1, Example 8 (comparative example) has a high basalt content and outstanding thermal insulation performance, and is suitable for large-diameter thermal insulation pipelines; It can be seen from Example 1 that fly ash reduces the overall weight and hardly affects the thermal conductivity; It can be seen from Example 2 that blast furnace slag improves the compressive strength but slightly increases the thermal conductivity; It can be seen from Example 3 that desulfurized ash may lead to an increase in thermal conductivity and increase the weight of the material; It can be seen from Example 4 that the balance of fly ash and blast furnace slag improves the thermal insulation performance; It can be seen from Example 5 that a good combination is obtained, but the thermal conductivity may decrease; It can be seen from Example 6 that slag leads to a slight improvement in thermal conductivity, but the overall performance is acceptable; As can be seen from Example 7, the components are balanced and suitable for conventional use; If the data is too little, you can do more groups.

[0036] By testing the thermal insulation performance of large-diameter insulated pipes produced with rock wool coils prepared with different admixture ratios, it can be known that by using fly ash, blast furnace slag or desulfurization ash as admixtures and selecting different ratios according to different use environments, large-diameter insulated pipes with rock wool coils as insulation materials can be prepared, which can effectively reduce the amount of basalt added and reduce costs. Blast furnace slag can provide certain adhesion and porosity, thereby improving the performance of large-diameter insulated pipes. At the same time, the use of industrial by-products and waste utilization can help reduce waste and reduce environmental impact, which is in line with the goals of sustainable development and resource recycling.

[0037] Embodiment 9

[0038] This embodiment provides a technical solution: the admixture is specifically fly ash, basalt accounts for 70% by weight, fly ash accounts for 20% by weight, adhesive accounts for 5% by weight, and other additives account for 5% by weight. The preparation of the thermal insulation material in step three specifically includes the following steps: Step S1: Raw material preparation: crushing and grinding basalt to a particle size of 200-500 mesh, collecting and sieving fly ash, using phenolic resin as a binder, and using waterproofing agent and fire retardant as other additives; Step S2: Mixing: according to the proportion, the prepared basalt, fly ash, phenolic resin, waterproofing agent and fire retardant are put into a mixer for dry mixing; Step S3: high temperature melting: the mixture is transferred to a melting furnace, and the melting temperature is set between 1400°C and 1600°C; Step S4: Fiberization: Using a fiberization device to process the molten mixture into filamentous rock wool fibers, and cooling and rapidly solidifying the molten liquid through a centrifugal and blowing process to form fine rock wool fibers; Step S5: Molding: Collect and compact the rock wool fibers to form a rock wool coil of desired thickness and density.

[0039] Take the same amount of the rock wool coil obtained in Example 1, the rock wool coil obtained in Example 8 and the rock wool coil obtained in Example 9 to test the performance of the prepared large-diameter thermal insulation pipe, and test its thermal conductivity, density, compressive strength and VOCs generation to obtain the following table:

[0040] As can be seen from Table 2, the thermal conductivity of Example 1 and Example 8 is relatively low, indicating that they maintain good thermal insulation ability and high compressive strength while suppressing the generation of VOCs by inert gas, which is due to the uniform fiber structure formed by the introduction of inert gas; The thermal conductivity of Example 9 is relatively high, which may be due to the increase of VOCs and the uneven distribution of pores in the material, which affects the thermal insulation performance. In addition, the density fluctuates greatly and there is a certain degree of non-uniformity. If the data is too little, more groups can be made.

[0041] By introducing inert gas during the melting process when preparing the insulation material, the generation of VOCs can be effectively suppressed. Through the performance of the rock wool coil, the insulation capacity and compressive strength of the large-diameter insulation pipes can be improved, thereby improving the performance of the large-diameter insulation pipes.

[0042] The above are only preferred embodiments of the present invention, which are only illustrative and not restrictive. Those skilled in the art understand that many changes, modifications, and even equivalences can be made to the present invention within the spirit and scope defined by the claims, but they will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a large-diameter insulated pipe, comprising material selection, pipe forming and surface treatment, insulation material preparation and large-diameter insulated pipe preparation, characterized in that: The specific steps include: Step 1: Material selection: Select pipe materials and insulation materials with excellent thermal stability and corrosion resistance; Step 2: Pipe forming and surface treatment: Select carbon steel, stainless steel or high-density polyethylene as the pipe material, and manufacture the selected material into a pipe of the required diameter and length through conventional welding, extrusion or molding processes; Step 3: Preparation of thermal insulation materials: rock wool is selected as the thermal insulation material, basalt ore is selected as the raw material, fly ash, blast furnace slag or desulfurized ash is selected as the admixture, adhesive and other additives are matched, inert gas is introduced during the melting process, and the rock wool coil is prepared; Step 4: Preparation of large diameter insulated pipes: Wrap the rock wool roll on the pipe, fix it with adhesive, cover the rock wool-coated pipe with waterproof and weather-resistant material, and test whether the insulation performance meets the standards.

2. The method for preparing a large diameter thermal insulation pipe according to claim 1, characterized in that: The admixture is specifically fly ash, the weight of the basalt is 70%, the weight of the fly ash is 20%, the weight of the adhesive is 5%, and the weight of other additives is 5%. The preparation of the thermal insulation material in step three specifically includes the following steps: Step S1: Raw material preparation: crushing and grinding basalt to a particle size of 200-500 mesh, collecting and sieving fly ash, using phenolic resin as a binder, and using waterproofing agent and fire retardant as other additives; Step S2: Inert gas preparation: nitrogen or helium is selected as the inert gas; Step S3: Mixing: according to the proportion, the prepared basalt, fly ash, phenolic resin, waterproofing agent and fire retardant are put into a mixer for dry mixing; Step S4: high temperature melting: the mixture is transferred to a melting furnace, an inert gas is introduced into the melting furnace, and the melting temperature is set between 1400° C. and 1600° C.; Step S5: Fiberization: Using a fiberization device to process the molten mixture into fine rock wool fibers, cooling the molten liquid and rapidly solidifying it through a centrifugal and blowing process to form fine rock wool fibers, and maintaining the injection of inert gas during solidification; Step S6: Molding: Collect and compact the rock wool fibers to form a rock wool coil of desired thickness and density.

3. The method for preparing a large diameter thermal insulation pipe according to claim 1, characterized in that: The admixture is specifically blast furnace slag, the weight of the basalt is 60%, the weight of the blast furnace slag is 30%, the weight of the adhesive is 5%, and the weight of other additives is 5%. The preparation of the thermal insulation material in step three specifically includes the following steps: Step N1: Raw material preparation: crushing and grinding basalt to 200-500 mesh, collecting and screening blast furnace slag, phenolic resin as adhesive, waterproofing agent and fire retardant as other additives; Step N2: Inert gas preparation: nitrogen or helium is selected as the inert gas; Step N3: Mixing: according to the proportion, put the prepared basalt, blast furnace slag, phenolic resin, waterproofing agent and fire retardant into a mixer for dry mixing; Step N4: high temperature melting: the mixture is transferred to a melting furnace, an inert gas is introduced into the melting furnace, and the melting temperature is set between 1400° C. and 1600° C.; Step N5: Fiberization: Use a fiberization device to process the molten mixture into fine rock wool fibers, and cool and rapidly solidify the molten liquid through centrifugal and blowing processes to form fine rock wool fibers, and keep the injection of inert gas during solidification; Step N6: Molding: Collect and compact the rock wool fibers to form a rock wool roll of desired thickness and density.

4. The method for preparing a large diameter thermal insulation pipe according to claim 1, characterized in that: The admixture is specifically desulfurized ash, the weight of the basalt is 60%, the weight of the desulfurized ash is 30%, the weight of the adhesive is 5%, and the weight of other additives is 5%. The preparation of the thermal insulation material in step three specifically includes the following steps: Step M1: Raw material preparation: crush and grind the basalt to a particle size of 200-500 mesh, collect and screen the desulfurized ash, use phenolic resin as a binder, and use waterproofing agent and fire retardant as other additives; Step M2: Inert gas preparation: nitrogen or helium is selected as the inert gas; Step M3: Mixing: according to the proportion, put the prepared basalt, desulfurized ash, phenolic resin, waterproofing agent and fire retardant into a mixer for dry mixing; Step M4: high temperature melting: the mixture is transferred to a melting furnace, an inert gas is introduced into the melting furnace, and the melting temperature is set between 1400° C. and 1600° C.; Step M5: Fiberization: Use fiberization equipment to process the molten mixture into filamentous rock wool fibers, and cool and rapidly solidify the molten liquid through centrifugal and blowing processes to form fine rock wool fibers, and keep the injection of inert gas during solidification; Step M6: Molding: Collect and compact the rock wool fibers to form a rock wool coil of desired thickness and density.

5. The method for preparing a large diameter thermal insulation pipe according to claim 1, characterized in that: The waterproof and weather-resistant material in step 4 is specifically PE, aluminum foil or galvanized steel plate.

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