Organic-inorganic composite pipeline thermal insulation material as well as preparation method and application thereof

Abstract

The invention provides an organic-inorganic composite pipeline thermal insulation material and a preparation method and application thereof.The preparation method comprises the steps that cement, modified chitosan (CM-QCCS) and a linear high-molecular polymer serve as raw materials, a cement hydration product is induced to be nucleated in a solution of the polymer and the modified chitosan through a directional freezing method, and aerogel is prepared; the cement / chitosan aerogel with a three-dimensional network structure and multiple functions is realized, and can be used as a composite thermal insulation material for ocean deepwater pipelines. The preparation process is simple, the used materials are environmentally friendly, green and sustainable development is met, and a new material and a new method are provided for the field of heat preservation and heat insulation for pipelines.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal insulation materials, and in particular to an organic-inorganic composite pipeline thermal insulation material and a preparation method and application thereof. Background Art

[0002] At present, in the field of petroleum industry, metal pipelines are the most widely used. Due to the different conveying media and conveying environments, people need to take different protective measures for metal pipelines, such as pressure resistance, heat resistance, corrosion resistance and scratch resistance, etc. In addition, with the increasing scope of offshore oil and gas exploitation, higher requirements are also put forward for the performance requirements of submarine oil pipeline insulation materials. As we all know, at a depth of more than 1500m in the ocean, the underwater temperature can reach below 3°C, and deep-sea oil production fluid is a high-temperature mixture of concentrated hydrocarbon gas, paraffin liquid, wax layer, water, etc., so at this low temperature, the high-temperature liquid in the pipeline will precipitate solid wax and hydrate, and the viscosity of crude oil will increase, which is easy to cause production accidents such as pipeline blockage. Therefore, it is necessary to effectively insulate the submarine pipeline through a thermal insulation layer. This type of pipeline insulation material must have the characteristics of low thermal conductivity and resistance to high hydrostatic pressure, and the material must have the characteristics of large quantity, wide range and low price.

[0003] Patent document CN103772635A "A method for preparing thermal insulation materials for marine oil and gas pipelines" discloses a thermal insulation material for marine oil and gas pipelines, more specifically, a pipeline material containing phase change materials. The pipeline thermal insulation material prepared by the invention method not only has the function of phase change temperature regulation, but also has low cost, good stability, can cope with sudden conditions such as sudden cooling, and has a long service life. It can be used in thermal insulation materials for offshore and deep-sea oil and gas pipelines, but the preparation method is too complicated and is not suitable for large-scale industrial production.

[0004] Patent document CN104356606A "A lightweight thermal insulation material for deep-water marine pipelines and its preparation method" discloses a lightweight thermal insulation material prepared by a reasonable combination and organic combination of hollow glass microspheres, fumed silica and epoxy resin and a vacuum mixing, stirring, pouring and curing molding process according to a formula. The disadvantage of this material is that the material density is relatively large.

[0005] Patent document CN101016366A "A rigid polyurethane foam plastic particularly suitable for pipeline insulation layer" discloses a method for preparing a rigid polyurethane foam suitable for pipeline insulation layer. The method uses composite polyether, catalyst, foam stabilizer, distilled water and foaming agent as raw material A component, and polyphenyl polymethyl isocyanate as raw material B component, and the two are foamed and cured to obtain a rigid polyurethane foam material. The advantage of this invention is that the thermal conductivity of the foam is low, but the disadvantage is that its compressive strength is generally insufficient (<0.3MPa), so it can only meet the needs of buried pipelines.

[0006] The oil and gas pipeline materials mentioned in the above patents are mainly polypropylene and polyurethane. Most of them improve the physical and chemical properties of the materials by adding functional materials to the parent materials. It can be seen that the current single parent material and the lack of applicability of functional materials are one of the difficulties to be solved in various patents. Aerogel material is a new type of high-efficiency thermal insulation material, which has been put into practical application in the fields of aerospace and civil thermal insulation. Its unique three-dimensional network structure gives the material significant characteristics such as low density, large specific surface area, high porosity and low thermal conductivity. The common SiO2 aerogel materials currently have the disadvantages of low compressive strength, complex preparation process and high cost, which seriously restrict their wide application in the field of thermal insulation. Therefore, it is of great significance to develop high-performance thermal insulation aerogel insulation materials with low raw materials and simple processes. Summary of the invention

[0007] Aiming at the problems of single parent material, complex preparation process, high cost and poor insulation effect of existing marine pipeline insulation materials. Based on the commonly used aerogel materials and the structural characteristics and active effects of cement and chitosan, this application proposes an organic-inorganic composite pipeline insulation material and its preparation method and application from the perspective of the synthesis of organic-inorganic composite aerogel materials. Cement, modified chitosan (CM-QCCS) and linear polymer are used as raw materials. The cement hydration products are induced to nucleate in the solution of polymer and modified chitosan by directional freezing to prepare aerogel, so as to realize a cement / chitosan aerogel with a three-dimensional network structure and multifunctionality, which can be used for composite thermal insulation materials for deep-water marine pipelines. The preparation process of this application is simple, and the materials used are environmentally friendly and in line with green and sustainable development, providing new materials and methods for the field of thermal insulation for pipelines.

[0008] An organic-inorganic composite pipe insulation material comprises the following raw materials in weight ratio:

[0009]

[0010] The modified chitosan is prepared by quaternizing carboxymethyl chitosan and then reacting it with polyoxometalate (POM) through electrostatic interaction.

[0011] The modified chitosan is prepared by the following steps: (S1) quaternization reaction: adding 2,3-epoxypropyltrimethylammonium chloride (GTA) to a carboxymethyl chitosan (CCS) aqueous solution, stirring the reaction, and obtaining a quaternized chitosan (QCCS) material; (S2) electrostatic assembly reaction: adding polyoxometalate to the system of step S1, stirring the reaction, and obtaining a modified chitosan (CM-QCCS).

[0012] The viscosity of the above-mentioned carboxymethyl chitosan is 10mPa.s-80mPa.s, and the carboxylation degree is not less than 80%; when the carboxymethyl chitosan is lower than this viscosity and carboxylation degree range, it is difficult for the organic-inorganic composite pipeline insulation material to form a three-dimensional grid structure and the working performance is poor; when the carboxymethyl chitosan is higher than this viscosity, its reaction activity is too low, which is not conducive to the reaction; the concentration of the above-mentioned carboxymethyl chitosan aqueous solution is 5%-7%.

[0013] The mass ratio of the above 2,3-epoxypropyltrimethylammonium chloride to carboxymethyl chitosan is (0.05-0.5):1.

[0014] The mass ratio of the polyoxometalate to the quaternized chitosan material is 1:(1.1-1.4).

[0015] In the above step (S1), the reaction temperature is 40-50°C, the reaction time is 24-48h, and the stirring rate is 1000-2000r / min; in the step (S2), the reaction temperature is 40-50°C, the reaction time is 3-6h, and the stirring rate is 600-1000r / min.

[0016] The polyoxometalate is phosphomolybdic acid H3[PMo 12 O 40 ] or silicomolybdic acid H4 [SiMo 12 O 40 ]. Among them [SiMo 12 O 40 ] 4- and [PMo 12 O 40 ] 3- The anionic groups can be charged with quaternized carboxymethyl chitosan.

[0017] The linear high molecular polymer is at least one of polyethylene glycol, polyacrylamide, polyvinyl alcohol and polyethylene imine.

[0018] The cement may be any one of sulphoaluminate cement, high aluminate cement, phosphate cement or the like.

[0019] The hydrophobic component is any one of methyltrimethoxysilane or triethoxyfluorosilane.

[0020] The foaming component is any one of hydrogen peroxide, sodium bicarbonate, ammonium carbonate and ammonium bicarbonate.

[0021] The organic solvent is any one of methanol, ethanol and isopropanol.

[0022] A method for preparing an organic-inorganic composite pipeline thermal insulation material comprises the following steps: (1) adding a modified chitosan solution to a dissolved linear high molecular polymer solution at room temperature, and then slowly adding a certain amount of cement component and an organic solvent, and stirring evenly; (2) adding a hydrophobic component to the solution in step (1), and stirring for reaction; (3) adding a foaming component to the solution in step (2), and stirring for reaction; (4) pouring the slurry in step (3) that is fully mixed evenly into a freezing mold, and using liquid nitrogen for directional freezing; (5) after freezing, thawing the entire frozen mold at room temperature, and waiting for it to return to room temperature; (6) after returning to room temperature, placing the entire mold in an oven for drying, thereby obtaining the organic-inorganic composite pipeline thermal insulation material.

[0023] The stirring time of the above step (1) is 0.5 to 2 hours, and the stirring rate is 500 to 2000 r / min; the stirring time of the step (2) is 0.5 to 1 hour, and the stirring rate is 500 to 1000 r / min; the stirring time of the step (3) is 1 to 5 minutes, and the stirring rate is 200 to 500 r / min; the freezing time of the step (4) is 1 to 2 hours, and the freezing temperature is -180 to -150°C; the drying temperature of the step (6) is 50-60°C, and the drying time is 12 to 24 hours.

[0024] The organic-inorganic composite pipe insulation material of the present application is mainly made of modified chitosan, linear polymer and cement, wherein cement is used as a skeleton to provide high mechanical strength; on the one hand, the modified chitosan has carboxyl groups and a three-dimensional network structure that can effectively disperse cement components, and on the other hand, the modified chitosan can participate in the formation reaction of CSH in the early stage of the hydration reaction, further improving the mechanical properties of the cement material. In addition, the newly added polyoxometalate POM unit can further support the skeleton function of cement due to its steric effect. As for the aerogel preparation process, the strength of the aerogel can be greatly improved and its thermal conductivity can be further reduced by qualitative freezing pore formation.

[0025] The organic-inorganic composite pipeline insulation material is suitable for pipelines in any field, especially in deep ocean water fields.

[0026] Compared with the prior art, this application has the following advantages:

[0027] (1) Cement is widely used in various types of buildings due to its high mechanical strength, good durability and high temperature resistance. Traditional cement materials are used as raw materials in the preparation of organic-inorganic composite aerogel insulation materials, and the directional freezing method is used to control the growth of ice crystals, thereby adjusting the microstructure of the composite aerogel to achieve specific performance goals. In addition, chitosan, a polysaccharide with a three-dimensional network structure, abundant sources, and environmental friendliness, is added during the preparation of the composite aerogel. It has multiple modified groups and contains a large number of functional groups that can react with active molecules in cement-based materials, affecting the cement hydration process and the formation of hydration products. Therefore, by adding cement and chitosan to the traditional aerogel components, the supramolecular effect between polymer chains is utilized, and the network is constructed from the structure to enhance it, ultimately achieving an organic-inorganic composite aerogel insulation material with high compressive strength, high hydrophobicity and excellent thermal insulation performance;

[0028] (2) The present application provides a method for preparing an organic-inorganic composite pipe insulation material. The raw materials used are easily available and environmentally friendly. The preparation technology route is simple and highly operable, and is suitable for industrial production. The organic-inorganic composite material is subjected to directional freezing by a directional freezing process, and it is easy to obtain an insulation material with high skeleton strength and large porosity.

[0029] (3) The present application improves the various working properties of the thermal insulation material by controlling the addition ratio of cement, foaming component, linear high molecular polymer and modified chitosan component, hydrophobic component and organic solvent, and the temperature rate time of the directional freezing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is the preparation process of organic-inorganic composite pipeline insulation material;

[0031] Figure 2 This is the microscopic morphology of the organic-inorganic composite thermal insulation material obtained in Example 5. DETAILED DESCRIPTION

[0032] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solution of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The preparation steps of the modified chitosan CM-QCCS used in each embodiment and comparative example of the present application are as follows: (S1) quaternization reaction: adding 2,3-epoxypropyltrimethylammonium chloride to a carboxymethyl chitosan aqueous solution, stirring the reaction, and obtaining a quaternized chitosan material; (S2) electrostatic assembly reaction: adding polyoxometalate to the system of step S1, stirring the reaction, and obtaining modified chitosan.

[0034] The ratios of the modified chitosan CM-QCCS used in the examples and comparative examples are shown in Table 1 below:

[0035] Table 1

[0036]

[0037]

[0038] The viscosity of the carboxymethyl chitosan in Table 1 is 10 mPa.s-80 mPa.s, the degree of carboxylation is 80%, and it is purchased from Shanghai Myrrel Biochemical Technology Co., Ltd.

[0039] In each embodiment and comparative example, the mass ratios of the components of the organic-inorganic composite pipeline insulation material are shown in Table 2 below:

[0040] Table 2

[0041]

[0042]

[0043] The preparation method of the organic-inorganic composite pipeline thermal insulation material in each embodiment and comparative example comprises the following steps: (1) adding a modified chitosan solution to a dissolved linear high molecular polymer solution at room temperature, and then slowly adding a certain amount of cement component and organic solvent, and stirring evenly; (2) adding a hydrophobic component to the solution in step (1), stirring for reaction; (3) adding a foaming component to the solution in step (2), and stirring for reaction; (4) pouring the slurry of step (3) that is fully mixed evenly into a freezing mold, and using liquid nitrogen for directional freezing; (5) after freezing, thawing the entire frozen mold at room temperature, and waiting for it to return to room temperature; (6) after returning to room temperature, placing the entire mold in an oven for drying, thereby obtaining the organic-inorganic composite pipeline thermal insulation material.

[0044] When the modified chitosan in Table 2 is used in the preparation process of organic-inorganic composite pipe insulation materials, it is necessary to first prepare a modified chitosan solution with a concentration of 3wt%; similarly, the concentration of the linear polymer solution is 5wt%; the concentration of the hydrophobic component is 20wt%; and the concentration of the foaming component is 30wt%.

[0045] The process parameters of the embodiments and comparative examples (time: stirring time / h; speed: stirring speed / r / min) are shown in Table 3 below:

[0046] Table 3

[0047]

[0048] Test Example 1: Performance Test

[0049] According to the ratios and processes in Tables 1 to 3, organic-inorganic composite pipe insulation materials were prepared to obtain relevant embodiments 1 to 9 and comparative examples 1 to 3. The performance of the materials formed in the relevant embodiments and comparative examples was tested, and the compressive strength and thermal conductivity test standards were based on GB / T 34336-2017 "Nanoporous Aerogel Composite Insulation Products". The test results are shown in Table 4 below:

[0050] Table 4

[0051]

[0052] It can be seen from the experimental results in Table 4 that the organic-inorganic composite aerogel pipeline insulation materials prepared in Examples 1 to 9 have the characteristics of high compressive strength, low density and low thermal conductivity, and can provide strong support for the research and development of high-performance thermal insulation materials with low raw materials and simple processes.

[0053] In addition, we also found that the compressive strength effects of Examples 1 to 9 are also different. The ratio between the linear polymer, modified chitosan and the foaming component can affect its working performance. This is because this type of material is expected to achieve a synergistic effect of aerogel skeleton strength and efficacy through the strong hydrogen bonding effect between the linear polymer and the modified chitosan molecules. Therefore, the quantitative ratio of the two should not be too high or too low. The three-dimensional network structure of the modified chitosan with too high a content will cause a cage effect on the carboxylic acid groups on the side chains, resulting in low dispersibility of the cement component and difficulty in improving the strength of the material; while the linear polymer with too low a content will make it difficult to form the material skeleton, let alone improve the strength of the material.

[0054] Compared with Examples 1 to 9, the working performance of Comparative Examples 1, 2 and 3 is significantly poorer, further confirming that it is difficult to improve the working performance of the material by lacking the corresponding modified chitosan component and cement component or by using conventional carboxymethyl chitosan.

[0055] Therefore, by using raw materials such as linear high molecular polymers, modified chitosan, cement components, hydrophobic components, foaming components and organic solvents in combination with a directional freezing process, an organic-inorganic composite thermal insulation material for deep-water marine pipelines with high compressive strength, high hydrophobicity and excellent thermal insulation properties can ultimately be achieved.

[0056] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An organic-inorganic composite pipeline thermal insulation material, characterized in that: The organic-inorganic composite pipeline insulation material comprises the following raw materials in weight ratio: The modified chitosan is prepared by quaternizing carboxymethyl chitosan and then interacting with polyoxometalate through electrostatic interaction.

2. The organic-inorganic composite pipe insulation material according to claim 1, characterized in that: The modified chitosan is prepared by the following steps: (S1) quaternization reaction: adding 2,3-epoxypropyltrimethylammonium chloride to a carboxymethyl chitosan aqueous solution, stirring and reacting to obtain a quaternized chitosan material; (S2) electrostatic assembly reaction: adding polyoxometalate to the system in step S1, stirring and reacting to obtain a modified chitosan.

3. The organic-inorganic composite pipe insulation material according to claim 2, characterized in that: The viscosity of the carboxymethyl chitosan is 10mPa.s-80mPa.s, and the carboxylation degree is not less than 80%; the concentration of the carboxymethyl chitosan aqueous solution is 5%-7%.

4. The organic-inorganic composite pipe insulation material according to claim 2, characterized in that: The mass ratio of the 2,3-epoxypropyltrimethylammonium chloride to carboxymethyl chitosan is (0.05-0.5):

1.

5. The organic-inorganic composite pipe insulation material according to claim 2, characterized in that: The mass ratio of the polyoxometalate to the quaternized chitosan material is 1:(1.1-1.4).

6. The organic-inorganic composite pipe insulation material according to claim 2, characterized in that: In the step (S1), the reaction temperature is 40-50°C, the reaction time is 24-48h, and the stirring rate is 1000-2000r / min; in the step (S2), the reaction temperature is 40-50°C, the reaction time is 3-6h, and the stirring rate is 600-1000r / min.

7. The organic-inorganic composite pipe insulation material according to claim 1, characterized in that: The polyoxometalate is phosphomolybdic acid H3[PMo 12 O 40 ] or silicomolybdic acid H4 [SiMo 12 O 40 ].

8. The organic-inorganic composite pipe insulation material according to claim 1, characterized in that: The linear high molecular polymer is at least one of polyethylene glycol, polyacrylamide, polyvinyl alcohol, and polyethylene imine; the cement is any one of sulphoaluminate cement, high aluminate cement, and phosphate cement; the hydrophobic component is any one of methyltrimethoxysilane or triethoxyfluorosilane; the foaming component is any one of hydrogen peroxide, sodium bicarbonate, ammonium carbonate, and ammonium bicarbonate; and the organic solvent is any one of methanol, ethanol, and isopropanol.

9. The method for preparing an organic-inorganic composite pipeline thermal insulation material according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) At room temperature, a modified chitosan solution is added to a dissolved linear polymer solution, and then a certain amount of cement component and an organic solvent are slowly added and stirred evenly; (2) a hydrophobic component is added to the solution of step (1) and stirred for reaction; (3) a foaming component is added to the solution of step (2) and stirred for reaction; (4) the slurry of step (3) is poured into a freezing mold and directional frozen using liquid nitrogen; (5) after freezing, the freezing mold is thawed at room temperature as a whole and allowed to return to room temperature; (6) after returning to room temperature, the mold is placed in an oven as a whole and dried to obtain an organic-inorganic composite pipeline insulation material.

10. The preparation method according to claim 9, characterized in that: The stirring time of step (1) is 0.5 to 2 hours, and the stirring rate is 500 to 2000 r / min; the stirring time of step (2) is 0.5 to 1 hour, and the stirring rate is 500 to 1000 r / min; the stirring time of step (3) is 1 to 5 minutes, and the stirring rate is 200 to 500 r / min; the freezing time of step (4) is 1 to 2 hours, and the freezing temperature is -180 to -150°C; the drying temperature of step (6) is 50-60°C, and the drying time is 12 to 24 hours.

11. An application of an organic-inorganic composite pipeline thermal insulation material, characterized in that: The organic-inorganic composite pipeline thermal insulation material is particularly suitable for deep-water marine areas; the organic-inorganic composite pipeline thermal insulation material is the organic-inorganic composite pipeline thermal insulation material described in any one of claims 1-8 or the organic-inorganic composite pipeline thermal insulation material obtained by the preparation method described in any one of claims 9-10.

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