Organic-inorganic composite pipe heat-insulating material, and preparation method and application thereof

Abstract

The application provides an organic-inorganic composite pipeline thermal insulation material and a preparation method and application thereof, adopts cement, modified chitosan (CM-QCCS) and linear polymer as raw materials, and prepares aerogel by directional freezing method to induce cement hydration product to nucleate in a solution of polymer and modified chitosan, so that the cement / chitosan aerogel with a three-dimensional network structure and multiple functions can be prepared and can be used for a composite thermal insulation material for ocean deepwater pipelines. The preparation process is simple, the materials used are environment-friendly and meet the green and sustainable development, and a new material and a new method are provided for the pipeline thermal insulation field.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation materials technology, specifically to an organic-inorganic composite pipe insulation material, its preparation method, and its application. Background Technology

[0002] Currently, metal pipelines are the most widely used in the petroleum industry. Due to the different transport media and environments, various protective measures are required for metal pipelines, such as pressure resistance, heat resistance, corrosion resistance, and scratch resistance. Furthermore, with the increasing scope of offshore oil and gas exploration, higher performance requirements are being placed on insulation materials for subsea oil pipelines. It is well known that at depths above 1500m in the ocean, underwater temperatures can reach below 3°C. Deep-sea oil produced fluids are high-temperature mixtures of concentrated hydrocarbons, paraffin liquids, waxy layers, and water. Therefore, at these low temperatures, the high-temperature liquids in the pipelines will precipitate solid wax and hydrates, increasing the viscosity of the crude oil and easily causing pipeline blockages and other production accidents. Therefore, effective insulation of subsea pipelines is necessary. Such pipeline insulation materials must have low thermal conductivity, resistance to high hydrostatic pressure, and be readily available, widely applicable, and inexpensive.

[0003] Patent document CN103772635A, "A Method for Preparing Thermal Insulation Material for Marine Oil and Gas Pipelines," discloses a thermal insulation material for marine oil and gas pipelines, more specifically, a pipeline material containing a phase change material. The pipeline insulation material prepared by this invention not only has phase change temperature regulation capabilities but also boasts low cost, good stability, resilience to sudden cooling and other unexpected conditions, and a long service life. It can be used in thermal insulation materials for near-shore and deep-sea oil and gas pipelines. However, the preparation method is overly complex and unsuitable for large-scale industrial production.

[0004] Patent document CN104356606A, "A lightweight thermal insulation material for deep-sea pipelines and its preparation method," discloses a lightweight thermal insulation material prepared by a process of vacuum mixing, stirring, casting, and curing of hollow glass microspheres, fumed silica, and epoxy resin in a reasonable combination and organic combination. The disadvantage of this material is its high density.

[0005] Patent document CN101016366A, "A Rigid Polyurethane Foam Particularly Suitable for Pipe Insulation Layers," discloses a method for preparing rigid polyurethane foam suitable for pipe insulation layers. This method uses composite polyether, catalyst, foam stabilizer, distilled water, and a blowing agent as raw materials for component A, and polyphenylene polymethyl isocyanate as raw material for component B. After foaming and curing, a rigid polyurethane foam material is obtained. The advantage of this invention is the low thermal conductivity of the foam; the disadvantage is that its compressive strength is generally insufficient (<0.3 MPa), so it can only meet the requirements of buried pipelines.

[0006] The oil and gas pipeline materials mentioned in the aforementioned patents are mostly polypropylene and polyurethane. Most of these materials improve their physical and chemical properties by adding functional materials to the base material. This highlights the current difficulty in addressing the issue of the limited availability of base materials and the lack of applicability of functional materials in various patents. Aerogel materials are a new type of high-efficiency thermal insulation material that has already found practical applications in aerospace and civil thermal insulation fields. Their unique three-dimensional network structure endows them with significant characteristics such as low density, large specific surface area, high porosity, and low thermal conductivity. However, commonly used SiO2 aerogel materials suffer from low compressive strength, complex manufacturing processes, and high costs, severely restricting their widespread application in thermal insulation. Therefore, developing high-performance thermal insulation aerogel materials with inexpensive raw materials and simple processes is of paramount importance. Summary of the Invention

[0007] Addressing the shortcomings of existing marine pipeline insulation materials, such as the reliance on single-material matrix, complex preparation processes, high costs, and unsatisfactory insulation performance, this application proposes an organic-inorganic composite pipeline insulation material, its preparation method, and applications. Based on commonly used aerogel materials and the structural characteristics and activity effects of cement and chitosan, this application utilizes cement, modified chitosan (CM-QCCS), and linear polymers as raw materials. An aerogel is prepared by inducing the nucleation of cement hydration products in a solution of polymer and modified chitosan through a directional freezing method. This results in a cement / chitosan aerogel with a three-dimensional network structure and multiple functions, suitable for use as a composite material for thermal insulation in deep-sea pipelines. The preparation process is simple, and the materials used are environmentally friendly and align with green and sustainable development, providing new materials and methods for pipeline thermal insulation.

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

[0009]

[0010] The modified chitosan described above is formed by quaternizing carboxymethyl chitosan and then electrostatically interacting it with polyoxometalates (POMs).

[0011] The modified chitosan was prepared by the following steps: (S1) Quaternization reaction: 2,3-epoxypropyltrimethylammonium chloride (GTA) was added to an aqueous solution of carboxymethyl chitosan (CCS), and after stirring, quaternized chitosan (QCCS) material was obtained; (S2) Electrostatic assembly reaction: polyoxometalate was added to the system in step S1, and after stirring, modified chitosan (CM-QCCS) was obtained.

[0012] The viscosity of the aforementioned carboxymethyl chitosan is 10 mPa·s-80 mPa·s, and the degree of carboxylation is not less than 80%. When the viscosity and degree of carboxyl chitosan are below this range, the organic-inorganic composite pipe insulation material is difficult to form a three-dimensional mesh structure, resulting in poor performance. When the viscosity of carboxymethyl chitosan is above this range, its reactivity is too low, which is not conducive to the reaction. The concentration of the aforementioned carboxymethyl chitosan aqueous solution is 5%-7%.

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

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

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

[0016] The above-mentioned polyoxometalate is phosphomolybdic acid H3[PMo 12 O 40 Or molybdenum silicate H4 [SiMo] 12 O 40 [SiMo] 12 O 40 ] 4- and [PMo 12 O 40 ] 3- The anionic groups can undergo charge assembly with quaternized carboxymethyl chitosan.

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

[0018] The cement can be any one of the following: sulfoaluminate cement, high aluminate cement, or phosphate cement.

[0019] The hydrophobic component is either 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, or isopropanol.

[0022] A method for preparing an organic-inorganic composite pipe insulation material includes the following steps: (1) At room temperature, a modified chitosan solution is added to a solution of a linear polymer that has been dissolved, and then a certain amount of cement components and organic solvent are slowly added and stirred evenly; (2) A hydrophobic component is added to the solution in step (1) and stirred to react; (3) A foaming component is added to the solution in step (2) and stirred to react; (4) The slurry from step (3) that has been thoroughly mixed is poured into a freezing mold and directionally frozen using liquid nitrogen; (5) After freezing, the entire freezing mold is thawed at room temperature and allowed to return to room temperature; (6) After returning to room temperature, the entire mold is placed in an oven and dried to obtain the organic-inorganic composite pipe insulation material.

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

[0024] The organic-inorganic composite pipe insulation material of this application uses modified chitosan, linear polymer, and cement as the main raw materials. Cement acts as the skeleton, providing high mechanical strength. Modified chitosan, on the one hand, possesses carboxyl groups and a three-dimensional network structure that can effectively disperse cement components; on the other hand, modified chitosan can participate in the formation reaction of CSH in the early stage of hydration, further improving the mechanical properties of the cement material. In addition, the newly added polyoxometalate POM units, due to their steric hindrance effect, can further support the skeleton function of cement. As for the aerogel preparation process, the qualitative cryogenic pore-forming method can greatly improve the strength of the aerogel and further reduce its thermal conductivity.

[0025] This organic-inorganic composite pipe insulation material is suitable for pipes in any field, especially for deep-sea applications.

[0026] This application has the following advantages over the prior art:

[0027] (1) Cement is widely used in various 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 growth of ice crystals is controlled by directional freezing method, thereby adjusting the microstructure of the composite aerogel to achieve specific performance goals. In addition, chitosan, a polysaccharide with a three-dimensional spatial network structure, abundant sources and environmental friendliness, is added during the preparation of composite aerogel. It has multiple modifying 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 interaction between polymer chains is utilized, and the network is constructed from the structure to enhance it, ultimately realizing an organic-inorganic composite aerogel insulation material with high compressive strength, high hydrophobicity and excellent thermal insulation performance;

[0028] (2) The method for preparing an organic-inorganic composite pipe insulation material provided in this application uses readily available and environmentally friendly raw materials. The preparation process is simple, highly operable, and suitable for industrial production. The organic-inorganic composite material is directionally frozen using a directional freezing process, which makes it easy to obtain insulation materials with high skeleton strength and large porosity.

[0029] (3) This application improves the various performance characteristics of thermal insulation materials by controlling the addition ratio of cement, foaming components, linear polymers and modified chitosan components, hydrophobic components and organic solvents, as well as the temperature, rate and time of the directional freezing process. Attached Figure Description

[0030] Figure 1 The preparation process of organic-inorganic composite pipe insulation materials;

[0031] Figure 2 The image shows the microstructure of the organic-inorganic composite thermal insulation material obtained in Example 5. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] The modified chitosan CM-QCCS used in the various embodiments and comparative examples of this application are prepared by the following steps: (S1) Quaternization reaction: 2,3-epoxypropyltrimethylammonium chloride is added to carboxymethyl chitosan aqueous solution, and after stirring, quaternized chitosan material is obtained; (S2) Electrostatic assembly reaction: polyoxometalate is added to the system in step S1, and after stirring, modified chitosan is obtained.

[0034] The proportions of modified chitosan CM-QCCS used in each embodiment and comparative example are shown in Table 1 below:

[0035] Table 1

[0036]

[0037]

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

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

[0040] Table 2

[0041]

[0042]

[0043] The preparation method of the organic-inorganic composite pipe insulation material in each embodiment and comparative example includes the following steps: (1) At room temperature, a modified chitosan solution is added to the dissolved linear polymer solution, and then a certain amount of cement component and organic solvent are slowly added and stirred evenly; (2) A hydrophobic component is added to the solution in step (1) and stirred to react; (3) A foaming component is added to the solution in step (2) and stirred to react; (4) The slurry in step (3) that is fully mixed is poured into a freezing mold and directionally frozen using liquid nitrogen; (5) After freezing, the entire freezing mold is thawed at room temperature and allowed to return to room temperature; (6) After returning to room temperature, the entire mold is placed in an oven for drying, and the organic-inorganic composite pipe insulation material is obtained.

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

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

[0046] Table 3

[0047]

[0048] Test Example 1: Performance Testing

[0049] Organic-inorganic composite pipe insulation materials were prepared according to the proportions and processes outlined in Tables 1-3, resulting in Examples 1-9 and Comparative Examples 1-3. The materials from the examples and comparative examples were subjected to performance testing. The compressive strength and thermal conductivity tests were conducted according to GB / T 34336-2017, "Nanoporous Aerogel Composite Insulation Products". The test results are shown in Table 4 below.

[0050] Table 4

[0051]

[0052] As can be seen from the experimental results in Table 4, the organic-inorganic composite aerogel pipe insulation materials prepared in Examples 1 to 9 have the characteristics of high compressive strength, low density and low thermal conductivity, which can provide strong support for the development of high-performance thermal insulation materials with inexpensive 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 foaming component can affect its performance. This is because this type of material aims to achieve a synergistic effect of aerogel skeleton strength through the strong hydrogen bonding between the linear polymer and modified chitosan. Therefore, the ratio of the two should not be too high or too low. If the modified chitosan content is too high, its three-dimensional network structure will cause a cage effect on the carboxylic acid groups on the side chains, resulting in low dispersion of cement components and difficulty in improving the strength of the material. On the other hand, if the linear polymer content is too low, the material skeleton will be difficult to form, and there will be no way to improve the strength of the material.

[0054] Compared with Examples 1-9, Comparative Examples 1, 2 and 3 showed significantly worse performance, further confirming that the absence of the corresponding modified chitosan component and cement component or the use of conventional carboxymethyl chitosan makes it difficult to improve the performance of the material.

[0055] Therefore, by using linear polymers, modified chitosan, cement components, hydrophobic components, foaming components, and organic solvents as raw materials, combined with directional freezing technology, an organic-inorganic composite thermal insulation material for deep-sea pipelines with high compressive strength, high hydrophobicity, and excellent thermal insulation performance can be finally achieved.

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

Claims

1. An organic-inorganic composite pipe insulation material, characterized in that, This organic-inorganic composite pipe insulation material comprises the following raw materials in the following weight ratios: Linear polymers 1-4, Modified chitosan 0.1~0.8, Cement component 4, Hydrophobic component 1, Foaming component 2~10, Organic solvent 10~20; The modified chitosan is formed by quaternizing carboxymethyl chitosan and then electrostatically interacting it with polyoxometalates. The linear polymer is at least one of polyethylene glycol, polyacrylamide, polyvinyl alcohol, and polyethyleneimine; The cement is any one of sulfoaluminate cement, high aluminate cement, or phosphate cement. The hydrophobic component is either methyltrimethoxysilane or triethoxyfluorosilane; The foaming component is any one of hydrogen peroxide, sodium bicarbonate, ammonium carbonate, and ammonium bicarbonate. The organic solvent is any one of methanol, ethanol, and isopropanol; Aerogels were prepared by inducing the nucleation of cement hydration products in a solution of polymer and modified chitosan through directional freezing, so as to realize cement / chitosan aerogels with three-dimensional network structure and multifunctionality, which can be used as composite thermal insulation materials for deep-sea pipelines. The modified chitosan was prepared by the following steps: (S1) Quaternization reaction: 2,3-epoxypropyltrimethylammonium chloride was added to carboxymethyl chitosan aqueous solution, and after stirring, quaternized chitosan material was obtained; (S2) Electrostatic assembly reaction: polyoxometalate was added to the system in step S1, and after stirring, modified chitosan was obtained. The concentration of the carboxymethyl chitosan aqueous solution is 5%-7%. The mass ratio of 2,3-epoxypropyltrimethylammonium chloride to carboxymethyl chitosan is (0.05~0.5):1; The mass ratio of the polyoxometalate to the quaternized chitosan material is 1:(1.1~1.4). The preparation method of the organic-inorganic composite pipe insulation material includes the following steps: (1) At room temperature, a modified chitosan solution is added to a solution of a linear polymer that has been dissolved, and then a certain amount of cement component and organic solvent are slowly added and stirred evenly; (2) A hydrophobic component is added to the solution in step (1) and stirred to react; (3) A foaming component is added to the solution in step (2) and stirred to react; (4) The slurry in step (3) that has been mixed evenly is poured into a freezing mold and directionally frozen using liquid nitrogen; (5) After freezing, the entire freezing mold is thawed at room temperature and allowed to return to room temperature; (6) After returning to room temperature, the entire mold is placed in an oven for drying, and the organic-inorganic composite pipe insulation material is obtained.

2. The organic-inorganic composite pipe insulation material according to claim 1, characterized in that: The viscosity of the carboxymethyl chitosan is 10 mPa·s-80 mPa·s, and the degree of carboxylation is not less than 80%.

3. The organic-inorganic composite pipe insulation material according to claim 1, characterized in that: In step (S1), the reaction temperature is 40~50 ℃, the reaction time is 24~48 h, and the stirring rate is 1000~2000 r / min; in step (S2), the reaction temperature is 40~50 ℃, the reaction time is 3~6 h, and the stirring rate is 600~1000 r / min.

4. 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 molybdenum silicate H4 [SiMo] 12 O 40 ].

5. The organic-inorganic composite pipe insulation material according to claim 1, characterized in that: The stirring time in step (1) is 0.5~2 h and the stirring rate is 500~2000 r / min; the stirring time in step (2) is 0.5~1 h and the stirring rate is 500~1000 r / min; the stirring time in step (3) is 1~5 min and the stirring rate is 200~500 r / min; the freezing time in step (4) is 1~2 h and the freezing temperature is -180~-150℃; the drying temperature in step (6) is 50-60℃ and the drying time is 12~24 h.

6. An application of an organic-inorganic composite pipe insulation material, characterized in that: This organic-inorganic composite pipe insulation material is suitable for deep-sea applications; the organic-inorganic composite pipe insulation material is the organic-inorganic composite pipe insulation material according to any one of claims 1-5.

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