Natural gas dehydration material, preparation method and dehydration process thereof

Abstract

The application belongs to the field of natural gas dehydration, and particularly relates to a natural gas dehydration material, a preparation method and a dehydration process thereof. The natural gas dehydration material comprises the following substances in parts by weight: 35-60 parts of molecular sieve particles; and 15-20 parts of modified silica gel particles; the molecular sieve is 4A molecular sieve, and the modified silica gel particles are salt-modified silica gel adsorption particles. The application selects 4A molecular sieve by further screening of the molecular sieve, improves the adsorption effect of the molecular sieve on water, and on this basis, the application forms effective compounding of the salt-modified silica gel adsorption particles and the molecular sieve particles, further improves the dehydration efficiency of the natural gas dehydration material, and improves the service life of the single molecular sieve particles.

Description

Technical Field

[0001] This invention belongs to the field of natural gas dehydration, and specifically relates to a natural gas dehydration material, its preparation method, and its dehydration process. Background Technology

[0002] Natural gas is a fossil fuel, primarily composed of a mixture of various alkanes, and typically contains impurities such as hydrogen sulfide, carbon dioxide, water, and organic sulfides. The presence of saturated water in natural gas exacerbates the corrosion of metallic materials by acidic gases. Both raw natural gas extracted from geological formations and desulfurized (carbonized) wet-processed natural gas generally contain saturated water. Under high pressure or low temperature, this saturated water will precipitate from the gas flow as liquid water. This liquid water will combine with hydrocarbons, acidic components, and other substances in the gas flow to form ice-like hydrates. The presence of hydrates increases the pressure drop during gas transmission, reduces the capacity of gas pipelines, and in severe cases, can block pipelines or other process equipment, affecting gas supply.

[0003] The principle of solid adsorption is that natural gas flow comes into contact with porous solid particles, and water molecules in the fluid are adsorbed by the surface of the solid pores. The adsorbent that has adsorbed water changes the equilibrium direction by changing the temperature and pressure, thereby removing the water.

[0004] Regarding the aforementioned related technologies, the inventors believe that the existing solid adsorption methods commonly use single molecular sieve materials for adsorption treatment. However, due to the poor adsorption capacity of molecular sieves with single structures, and the fact that the desorption and adsorption processes can easily damage the molecular sieve structure, the lifespan and adsorption quality of the molecular sieve materials are reduced. Summary of the Invention

[0005] To overcome the shortcomings of existing molecular sieves used in natural gas dehydration, such as poor adsorption capacity and short lifespan, this application provides a natural gas dehydration material, preparation method, and dehydration process, employing the following technical solution: Firstly, this application provides a natural gas dehydration material, employing the following technical solution: A natural gas dehydration material comprising the following parts by weight: 35-60 parts of molecular sieve particles; 15-20 parts of modified silica gel particles; wherein the molecular sieve is a 4A molecular sieve, and the modified silica gel particles are salt-modified silica gel adsorbent particles.

[0006] By adopting the above technical solution, this application further screens the molecular sieve and selects 4A molecular sieve, which improves the adsorption effect of the molecular sieve on water. On this basis, this application further improves the dehydration efficiency of the natural gas dehydration material and increases the service life of the single molecular sieve particle by forming an effective compound with salt-modified silica gel adsorption particles and molecular sieve particles.

[0007] Furthermore, the salt-modified silica gel adsorbent particles are prepared by the following method: after drying the silica gel, it is added to a calcium chloride / magnesium ethanol solution, ultrasonically dispersed and impregnated, and the dispersion is collected; the dispersion is taken and filtered, dried and collected to obtain the dried particles, thus preparing the modified silica gel particles.

[0008] By adopting the above technical solution, this application modifies silica gel using chloride salts. Chemical adsorption refers to the binding of 1, 2, 4, or 6 water molecules to each calcium chloride and magnesium chloride molecule within the pores at low humidity, forming crystalline hydrates; at high humidity, calcium chloride and magnesium chloride form a solution within the pores. Based on this, the large, sheet-like solid particles of the modified silica gel are partially broken down, forming smaller particles, resulting in a finer pore distribution. The silica gel surface is also rougher and more irregular, increasing the specific surface area and facilitating adsorption.

[0009] Meanwhile, this application modifies the silica gel by using chloride salts. Hydroxyl groups on the silica gel surface form hydrogen bonds with ethanol. When the porous structure accommodates calcium chloride, the hygroscopic enhancement effect of calcium chloride is better, and the fixation effect of calcium chloride is better. This greatly reduces the possibility of liquidation. While effectively improving the water adsorption capacity, it further improves the anti-crack performance of the dehydration material after desorption, thereby improving the service life of the dehydration material.

[0010] Furthermore, the molecular sieve particles are hydrophilic modified carbon molecular sieve particles.

[0011] By adopting the above technical solution, the present application optimizes the molecular sieve particles. Since carbon molecular sieve particles have good adsorption and desorption properties, the present application performs hydrophilic modification on them to improve the property that traditional carbon molecular sieves cannot adsorb water, thereby achieving both good service life and adsorption capacity in actual use.

[0012] Further, the hydrophilic modified carbon molecular sieve particles are prepared using the following method: p-phenylenediamine and p-aminophenol are mixed and dissolved in N,N-dimethylacetamide, stirred and mixed, and 4,4'-biphenyltetracarboxylic acid dianhydride is added to obtain a reactant; 4,4'-bipyridine-ethanol is dissolved and added to the reactant, stirred and mixed, and reacted under an ice-water bath. After the reaction is completed, it is kept at room temperature; the filter cake is collected, dried and collected to obtain dry particles, and the dry particles are placed under an inert atmosphere for pyrolysis treatment. After washing with nitric acid, the hydrophilic modified carbon molecular sieve particles can be obtained.

[0013] By adopting the above technical solution, this application uses polyimide as the carbon source for carbonization treatment to prepare molecular sieve particles. The addition of 4,4'-bipyridine allows for the doping of more nitrogen elements onto the surface of the carbon molecular sieve, improving its affinity for water. Furthermore, this application modifies the carbon molecular sieve through acid washing. After nitric acid washing, the carbon molecular sieve forms some ultraporous structures, which are beneficial for providing water vapor adsorption sites. In addition, the oxidizing property of nitric acid introduces some oxygen-containing polar functional groups at the edge of the carbon material, increasing the surface polarity of the carbon material and achieving superaffinity for water molecules.

[0014] Furthermore, the pyrolysis treatment temperature is 450–650°C.

[0015] By adopting the above technical solution, this application optimizes the pyrolysis temperature to facilitate the formation of richer pore structures in carbon molecular sieves. The optimized pyrolysis temperature is beneficial to improving the hydrophilicity of carbon materials because a relatively low pyrolysis temperature retains more hydrophilic sites on the carbon wall. However, a high pyrolysis temperature can increase pore volume and increase water vapor adsorption. Therefore, it is necessary to select an appropriate pyrolysis temperature to balance the hydrophilicity and water vapor capture capacity of carbon materials.

[0016] Furthermore, the hydrophilic modified carbon molecular sieve particles are Cu-containing hydrophilic modified carbon molecular sieve particles, which are prepared by the following scheme: p-phenylenediamine and p-aminophenol are mixed and dissolved in N,N-dimethylacetamide, stirred and mixed, and 4,4'-biphenyltetracarboxylic acid dianhydride is added to obtain a reactant; 4,4'-bipyridine-ethanol and copper chloride solution are dissolved and added to the reactant, stirred and mixed, and reacted under an ice-water bath. After the reaction is completed, it is kept at room temperature; the filter cake is collected, dried and collected to obtain dry particles, and the dry particles are placed under an inert atmosphere for pyrolysis treatment. After washing with nitric acid, the hydrophilic modified carbon molecular sieve particles can be obtained.

[0017] By adopting the above technical solution, this application further optimizes the hydrophilic modification technical solution. On the one hand, the doping energy of copper element can coordinate with 4,4'-bipyridine and form a metal-organic framework structure in the carbon molecular sieve, which is dispersed in the phenolic polymer framework. 2+ The metal-organic framework formed with 4,4′-bipyridine is highly dispersed and small in size in the phenolic polymer, without disrupting the cross-linking structure of the phenolic-derived carbon framework. This also enables the material to maintain good mechanical strength, ensuring that the carbon molecular sieve material maintains good pore structure and durability during use.

[0018] On the other hand, the technical solution of this application uses Cu 2+In organic combination with 4,4′-bipyridine, more N-doped sites remain in the carbon molecular sieve, which also anchor more Cu sites. During pyrolysis, Cu agglomerates and precipitates out, and after acid washing, polar defect sites are formed on the surface, which improves the hydrophilicity of the material and thus improves the water absorption of the carbon molecular sieve material.

[0019] Secondly, this application provides a method for preparing a natural gas dehydration material, which is prepared by the following scheme: mixed modified silica gel particles and molecular sieve particles and dried at 75-80°C for 24 hours; the dried particles are collected and placed under a humidity of 75-80% for 24 hours for moisture absorption treatment; after the moisture absorption is completed, the particles are placed under a temperature of 100-110°C for 20-24 hours for heat preservation and activation, and the natural gas dehydration material can be prepared.

[0020] By adopting the above technical solution, and through the technical solution of this application compared with the traditional simple compounding method, the dehydration performance of natural gas dehydration material is further improved by activation treatment. The activated solution can effectively remove the crystal water in the metal salt hydrate in the natural gas dehydration material, thereby improving the water absorption of the natural gas dehydration material.

[0021] Thirdly, this application provides a natural gas dehydration process using natural gas dehydration materials, comprising the following steps: the natural gas to be separated is first passed through a filter separator to remove impurities, and then fed into an adsorption pipeline and a regeneration pipeline respectively; the adsorption pipeline is fed into an adsorption tower A, which is pressurized and lined with natural gas dehydration materials, for dehydration treatment, and the dehydrated natural gas is collected; the gas in the regeneration pipeline is heated and fed into an adsorption tower B, which is depressurized and lined with natural gas dehydration materials, so that the water adsorbed in the adsorption tower B is desorbed and recovered to a heat exchanger to recover heat; the gas after heat recovery is cooled by an air cooler, and after the free water is separated by a dehydration separator, it enters the adsorption tower A, which is lined with natural gas dehydration materials, for dehydration treatment, thus completing the cycle.

[0022] By adopting the above technical solution, this application selects a heat exchanger to recover part of the heat of the regenerated gas, thereby reducing the heating load and the electrical load of the air cooler. On this basis, the regenerated gas uses the pressure difference to circulate itself, eliminating the need for a regenerated gas compressor, reducing the number of moving parts and improving the reliability of the device.

[0023] Furthermore, the pressure difference between the depressurized adsorption tower B and the pressurized adsorption tower A is ≥7.5MPa.

[0024] By adopting the above technical solution, the natural gas adsorbent material prepared in this application has good durability, enabling it to withstand large pressure changes during actual use, thereby effectively improving the dehydration performance and extending the dehydration life of the natural gas dehydration material.

[0025] In summary, this application includes at least one of the following beneficial technical effects:

[0026] First, this application modifies silica gel using chloride salts. Chemical adsorption refers to the binding of 1, 2, 4, or 6 water molecules to each calcium chloride and magnesium chloride molecule within the pores at low humidity, forming crystalline hydrates; at high humidity, calcium chloride and magnesium chloride form a solution within the pores. Based on this, the large, sheet-like solid particles of the modified silica gel are partially broken down, forming smaller particles, resulting in a finer pore distribution. The silica gel surface is also rougher and more irregular, increasing the specific surface area and facilitating adsorption.

[0027] Secondly, this application uses polyimide as the carbon source for carbonization treatment to prepare molecular sieve particles. The addition of 4,4'-bipyridine allows for the doping of more nitrogen elements onto the surface of the carbon molecular sieve, improving its affinity for water. Furthermore, this application modifies the carbon molecular sieve through acid washing. After nitric acid washing, the carbon molecular sieve forms some ultraporous structures, which are beneficial for providing water vapor adsorption sites. In addition, the oxidizing property of nitric acid introduces some oxygen-containing polar functional groups at the edge of the carbon material, increasing the surface polarity of the carbon material and achieving superaffinity for water molecules.

[0028] Third, this application further optimizes the hydrophilic modification technology. On the one hand, the doping of copper element can coordinate with 4,4'-bipyridine and form a metal-organic framework structure in the carbon molecular sieve. It is dispersed in the phenolic polymer framework. The metal-organic framework formed by Cu2+ and 4,4'-bipyridine is highly dispersed in the phenolic polymer and has a small size. It does not destroy the cross-linking structure of the phenolic-derived carbon framework. This also enables the material to maintain good mechanical strength and ensures that the carbon molecular sieve material maintains good pore structure and durability during use.

[0029] On the other hand, the technical solution of this application, through the organic combination of Cu2+ and 4,4′-bipyridine, leaves more N doping sites in the carbon molecular sieve, and also further anchors more Cu sites. During the pyrolysis process, Cu2+ agglomerates and precipitates out, and after acid washing, polar defect sites are formed on the surface, which improves the hydrophilicity of the material and thus improves the water absorption of the carbon molecular sieve material. Detailed Implementation

[0030] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims.

[0031] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0032] There are no particular restrictions on the purity of any of the raw materials used in this invention. However, this invention preferably uses analytical grade or the purity requirements conventional in the field of polypropylene material preparation.

[0033] All raw materials of this invention are conventional in the field, and each brand name and abbreviation is clear and distinct in its relevant application. Those skilled in the art can purchase them from the market or prepare them by conventional methods based on the brand name, abbreviation and corresponding application.

[0034] The present application will be further described in detail below with reference to the embodiments.

[0035] Preparation Example 1:

[0036] Take 2 kg of dried silica gel and add it to 0.5 kg of 10% calcium chloride-ethanol solution and 0.3 kg of 5% magnesium chloride-ethanol solution. Disperse the solution by ultrasonication at 200 W and impregnate it for 36 h. Collect the dispersion. Take the dispersion and filter it. Dry it at 60 °C to obtain the dried particles, which can be used to prepare the modified silica gel particles 1.

[0037] Preparation Example 2:

[0038] After drying 3 kg of silica gel, add it to 0.5 kg of 10% calcium chloride-ethanol solution and 0.4 kg of 5% magnesium chloride-ethanol solution. Disperse the solution by ultrasonication at 250 W and impregnate it for 36 h. Collect the dispersion. Take the dispersion and filter it. Dry it at 67 °C to obtain the dried particles, which can be used to prepare the modified silica gel particles 2.

[0039] Preparation Example 3:

[0040] Take 5 kg of dried silica gel and add it to 0.5 kg of 10% calcium chloride-ethanol solution and 0.5 kg of 5% magnesium chloride-ethanol solution. Disperse the solution by ultrasonication at 300 W and impregnate it for 36 h. Collect the dispersion. Take the dispersion and filter it. Dry it at 75 °C to obtain the dried particles, which can be used to prepare the modified silica gel particles 3.

[0041] Preparation Example 4:

[0042] Take 2.1–2.5 kg of p-phenylenediamine and 1.1–1.5 kg of p-aminophenol, mix and dissolve them in 750–800 kg of N,N-dimethylacetamide, stir and mix, and add 7.5–8.5 kg of 4,4'-biphenyltetracarboxylic acid dianhydride to obtain the reactant; take 0.5 mol / L of 4,4'-bipyridine-ethanol and dissolve it in it and add it to the reactant, controlling the molar ratio of 4,4'-bipyridine to p-phenylenediamine to be 1:3, stir and mix, and react in an ice-water bath at 0–5 °C. After the reaction is completed, keep it at room temperature; filter and collect the filter cake, dry and collect the dry particles, take the dry particles and place them in argon gas and pyrolysis treatment at 450–650 °C, wash with 10% nitric acid by mass fraction, and the hydrophilic modified carbon molecular sieve particles 1 can be prepared.

[0043] Preparation Example 5:

[0044] 2.1 kg of p-phenylenediamine and 1.1 kg of p-aminophenol were mixed and dissolved in 750 kg of N,N-dimethylacetamide. The mixture was stirred and 7.5 kg of 4,4'-biphenyltetracarboxylic acid dianhydride was added to obtain the reactant. 0.5 mol / L of 4,4'-bipyridine-ethanol was dissolved and added to the reactant, controlling the molar ratio of 4,4'-bipyridine to p-phenylenediamine to be 1:3. The mixture was stirred and reacted in an ice-water bath at 0–5 °C. After the reaction was completed, the mixture was kept at room temperature. The filter cake was collected, dried, and the dried particles were placed in an argon atmosphere at 550 °C for pyrolysis. After washing with 10% nitric acid, the hydrophilic modified carbon molecular sieve particles 2 were obtained.

[0045] Preparation Example 6:

[0046] 2.5 kg of p-phenylenediamine and 1.5 kg of p-aminophenol were mixed and dissolved in 800 kg of N,N-dimethylacetamide. The mixture was stirred and 8.5 kg of 4,4'-biphenyltetracarboxylic acid dianhydride was added to obtain the reactant. 0.5 mol / L of 4,4'-bipyridine-ethanol was dissolved and added to the reactant, controlling the molar ratio of 4,4'-bipyridine to p-phenylenediamine to be 1:3. The mixture was stirred and reacted in an ice-water bath at 0–5 °C. After the reaction was completed, the mixture was kept at room temperature. The filter cake was collected, dried, and the dried particles were placed in argon gas and pyrolyzed at 650 °C. After washing with 10% nitric acid, the hydrophilic modified carbon molecular sieve particles 3 were obtained.

[0047] Preparation Example 7:

[0048] 2.1 kg of p-phenylenediamine and 1.1 kg of p-aminophenol were mixed and dissolved in 750 kg of N,N-dimethylacetamide. The mixture was stirred and 7.5 kg of 4,4'-biphenyltetracarboxylic acid dianhydride was added to obtain the reactant. 0.5 mol / L of 4,4'-bipyridine-ethanol was dissolved and added to the reactant, controlling the Cu content.2+ The molar ratio of 4,4'-bipyridine to p-phenylenediamine was 2:3:6. The mixture was stirred and reacted in an ice-water bath at 0-5°C. After the reaction was completed, the mixture was kept at room temperature. The filter cake was filtered and collected. The dried particles were collected and then placed under argon gas and pyrolyzed at 550°C. After washing with 10% nitric acid, the hydrophilic modified carbon molecular sieve particles 4 were prepared.

[0049] Example 1:

[0050] A natural gas dehydration material comprises 35 kg of 4A-grade molecular sieve with a specific surface area of ​​650 and 15 kg of modified silica gel particles. A method for preparing the natural gas dehydration material is as follows: first, the modified silica gel particles and molecular sieve particles are mixed and dried at 75°C for 24 h; the dried particles are collected and placed under a humidity of 75% for 24 h for moisture absorption treatment; after moisture absorption is completed, they are placed at 100°C for 20 h for heat preservation and activation, thus obtaining the natural gas dehydration material.

[0051] Example 2:

[0052] A natural gas dehydration material comprises a 4A-grade molecular sieve with a specific surface area of ​​650 and 17 kg of modified silica gel particles. A method for preparing the natural gas dehydration material is as follows: first, the modified silica gel particles and molecular sieve particles are mixed and dried at 77°C for 24 hours; the dried particles are collected and placed under a humidity of 77% for 24 hours to absorb moisture; after moisture absorption is complete, they are placed at 105°C for 22 hours to activate, thus obtaining the natural gas dehydration material.

[0053] Example 3:

[0054] A natural gas dehydration material comprises a 4A-grade molecular sieve with a specific surface area of ​​650 and 20 kg of modified silica gel particles. A method for preparing the natural gas dehydration material is as follows: first, the modified silica gel particles and molecular sieve particles are mixed and dried at 80°C for 24 hours; the dried particles are collected and placed under a humidity of 80% for 24 hours to absorb moisture; after moisture absorption is complete, they are placed at 110°C for 24 hours to activate, thus obtaining the natural gas dehydration material.

[0055] Example 4:

[0056] A natural gas dehydration material comprises a 4A-grade molecular sieve with a specific surface area of ​​650 and 20 kg of modified silica gel particles. A method for preparing the natural gas dehydration material is as follows: first, the modified silica gel particles and molecular sieve particles are mixed and dried at 80°C for 24 hours; the dried particles are collected and placed under a humidity of 80% for 24 hours to absorb moisture; after moisture absorption is complete, they are placed at 110°C for 24 hours to activate, thus obtaining the natural gas dehydration material.

[0057] Example 5:

[0058] A natural gas dehydration material comprises a 4A-grade molecular sieve with a specific surface area of ​​650 and 20 kg of modified silica gel particles. A method for preparing the natural gas dehydration material is as follows: first, the modified silica gel particles and molecular sieve particles are mixed and dried at 80°C for 24 hours; the dried particles are collected and placed under a humidity of 80% for 24 hours to absorb moisture; after moisture absorption is complete, they are placed at 110°C for 24 hours to activate, thus obtaining the natural gas dehydration material.

[0059] Example 6:

[0060] A natural gas dehydration material comprises 60 kg of molecular sieve particles 1 and 20 kg of modified silica gel particles 1; a method for preparing the natural gas dehydration material is as follows: first, the modified silica gel particles and molecular sieve particles are mixed and dried at 80°C for 24 h; the dried particles are collected and placed under a humidity of 80% for 24 h for moisture absorption treatment; after the moisture absorption is completed, they are placed at 110°C for heat preservation and activation for 24 h to obtain the natural gas dehydration material.

[0061] Example 7:

[0062] A natural gas dehydration material comprises 60 kg of molecular sieve particles 2 and 20 kg of modified silica gel particles 1; a method for preparing the natural gas dehydration material is as follows: first, the modified silica gel particles and molecular sieve particles are mixed and dried at 80°C for 24 h; the dried particles are collected and placed under a humidity of 80% for 24 h for moisture absorption treatment; after the moisture absorption is completed, they are placed at 110°C for heat preservation and activation for 24 h to obtain the natural gas dehydration material.

[0063] Example 8:

[0064] A natural gas dehydration material comprises 60 kg of molecular sieve particles 3 and 20 kg of modified silica gel particles 1; a method for preparing the natural gas dehydration material is as follows: first, the modified silica gel particles and molecular sieve particles are mixed and dried at 80°C for 24 h; the dried particles are collected and placed under a humidity of 80% for 24 h for moisture absorption treatment; after the moisture absorption is completed, they are placed at 110°C for heat preservation and activation for 24 h to obtain the natural gas dehydration material.

[0065] Example 9:

[0066] A natural gas dehydration material comprises 60 kg of molecular sieve particles 4 and 20 kg of modified silica gel particles 1; a method for preparing the natural gas dehydration material is as follows: first, the modified silica gel particles and molecular sieve particles are mixed and dried at 80°C for 24 h; the dried particles are collected and placed under a humidity of 80% for 24 h for moisture absorption treatment; after the moisture absorption is completed, they are placed at 110°C for heat preservation and activation for 24 h to obtain the natural gas dehydration material.

[0067] Comparative Example 1:

[0068] Comparative Example 1 is a comparative example of Example 1, and the natural gas dehydration material used is a 4A-grade molecular sieve with a specific surface area of ​​650.

[0069] Performance testing:

[0070] The natural gas dehydration materials prepared in Examples 1-9 and Comparative Example 1 were applied to the natural gas dehydration process. The specific process is as follows: The natural gas to be separated is first passed through a filter separator to remove impurities, and then passed into an adsorption pipeline and a regeneration pipeline respectively; the adsorption pipeline is passed into an adsorption tower A, which is lined with natural gas dehydration material and pressurized, for dehydration treatment, and the dehydrated natural gas is collected; the gas in the regeneration pipeline is treated by a heater and then passed into an adsorption tower B, which is lined with natural gas dehydration material and depressurized, so that the water adsorbed in the adsorption tower B is desorbed and recovered to the heat exchanger to recover heat; the gas after heat recovery is cooled by an air cooler, and after the free water is separated by the dehydration separator, it enters the adsorption tower A, which is lined with natural gas dehydration material, for dehydration treatment, and the cycle is completed.

[0071] The main process parameters are set as follows: heater: 60kW, cooler power load: 2.0kW, molecular sieve consumption: 2000kg.

[0072] Specifically, its application consumption is measured:

[0073] In Examples 1-8, the molecular sieve switching cycle is 20 hours, and the molecular sieve consumption is 0.4 t / a.

[0074] In Comparative Example 1, the molecular sieve switching cycle was 12 hours, and the molecular sieve usage was 0.6 t / a.

[0075] Further tests were conducted on the natural gas dehydration materials prepared in Examples 1-8 and the natural gas dehydration material in Comparative Example 1 to test their water adsorption.

[0076] (1) After drying the natural gas dehydration materials prepared in Examples 1 to 8 and the natural gas dehydration materials in Comparative Example 1, take them out and weigh them, and then put them into a high and low temperature damp heat test chamber. Weigh and record the mass every 0.5 hours. When the mass change between adjacent times does not exceed 0.1%, it is considered to have reached saturation.

[0077] (2) The natural gas dehydration materials prepared in Examples 1-8 and the natural gas dehydration material in Comparative Example 1 were dried at 110°C for 5 hours to obtain the desorbed natural gas dehydration material. The moisture absorption was tested after each cycle. Specific test results are as follows:

[0078] Table 1 Performance Testing

[0079]

[0080] As can be seen from the technical solutions and performance test tables of Examples 1-8 and Comparative Example 1, the natural gas dehydration material prepared in this example has good dehydration performance and durability. This indicates that the technical solution of this application modifies silica gel with chloride salts. Since chemical adsorption refers to the binding of 1, 2, 4, or 6 water molecules to each calcium chloride and magnesium chloride in the pores at low humidity to form crystalline hydrates, and calcium chloride and magnesium chloride forming a solution in the pores at high humidity, the large sheet-like solid particles of the modified silica gel are partially destroyed, forming some fine particles, thus resulting in a finer pore distribution. The surface of the silica gel is also rougher and more irregular, increasing the specific surface area and facilitating adsorption.

[0081] Based on the technical solutions of Examples 1-3 and Examples 4-9, it is explained that the technical solution of this application uses polyimide as a carbon source to prepare molecular sieve particles through carbonization treatment, thereby doping the surface of the carbon molecular sieve with more N elements and improving the affinity of the carbon molecular sieve for water.

[0082] Finally, by comparing the technical solutions of Examples 4-8 and Example 9, it is explained that the optimized hydrophilic modification technical solution of this application utilizes the doping energy of copper to coordinate with 4,4'-bipyridine and form a metal-organic framework structure in the carbon molecular sieve. This structure is dispersed within the phenolic polymer framework, enabling the material to maintain good mechanical strength and ensuring that the carbon molecular sieve material maintains good pore structure and durability during use. It is also explained that Cu... 2+ In organic combination with 4,4′-bipyridine, more N-doped sites remain in the carbon molecular sieve, which also anchor more Cu sites. During pyrolysis, Cu agglomerates and precipitates out, and after acid washing, polar defect sites are formed on the surface, which improves the hydrophilicity of the material and thus improves the water absorption of the carbon molecular sieve material.

[0083] The foregoing has provided a detailed description of a natural gas dehydration material, its preparation method, and its dehydration process provided by this invention. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of these embodiments are merely for the purpose of helping to understand the method and core ideas of this invention, including the best mode, and also to enable any person skilled in the art to practice this invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to this invention without departing from the principles of this invention, and these improvements and modifications also fall within the protection scope of the claims of this invention. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the textual description of the claims, or if they include equivalent structural elements that are not substantially different from the textual description of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A natural gas dehydration material, characterized in that, Includes the following parts by weight: 35–60 parts of molecular sieve particles; 15-20 parts modified silica gel particles; The modified silica gel particles are salt-modified silica gel adsorbent particles; The salt-modified silica gel adsorbent particles were prepared using the following method: After drying the silica gel, add it to a calcium chloride / magnesium chloride-ethanol solution, disperse it ultrasonically and impregnate it, and collect the dispersion. The dispersion was collected, filtered, dried, and dried granules were obtained, thus the modified silica gel granules were prepared. The molecular sieve particles are hydrophilic modified carbon molecular sieve particles; The hydrophilic modified carbon molecular sieve particles are Cu-containing hydrophilic modified carbon molecular sieve particles, which are prepared using the following method: p-Phenylenediamine and p-aminophenol were mixed and dissolved in N,N-dimethylacetamide, stirred and mixed, and 4,4'-biphenyltetracarboxylic acid dianhydride was added to obtain the reactant; Add 4,4'-bipyridine-ethanol and copper chloride to the reactants, stir and mix, and react in an ice-water bath. After the reaction is complete, keep it at room temperature. The filter cake is filtered and collected, dried to obtain dry particles, and then placed in an inert atmosphere for pyrolysis treatment. After washing with nitric acid, the Cu-containing hydrophilic modified carbon molecular sieve particles are obtained.

2. The natural gas dehydration material according to claim 1, characterized in that, The pyrolysis treatment temperature is 450–650℃.

3. The method for preparing the natural gas dehydration material according to any one of claims 1 to 2, characterized in that, The natural gas dehydration material is prepared using the following method: The modified silica gel particles and molecular sieve particles were mixed and dried at 75-80℃ for 24 hours. Collect the dried particles and place them under a humidity of 75-80% for 24 hours to absorb moisture. After the moisture absorption is complete, place them at 100-110℃ for 20-24 hours to activate them, thus obtaining the natural gas dehydration material.

4. A natural gas dehydration process using the natural gas dehydration material according to any one of claims 1 to 2, characterized in that, The following steps are included: The natural gas that needs to be separated is first passed through a filter separator to remove impurities, and then fed into the adsorption pipeline and the regeneration pipeline respectively. The natural gas in the adsorption pipeline is passed into adsorption tower A, which is lined with natural gas dehydration material and pressurized. After dehydration treatment, the dehydrated natural gas is collected. The gas in the regeneration pipeline is heated and then introduced into adsorption tower B, which is lined with natural gas dehydration material and depressurized, so that the water adsorbed in adsorption tower B is desorbed and sent to a heat exchanger to recover heat. After the heat is recovered, the gas is cooled by an air cooler, and after the free water is separated by a dehydration separator, it enters adsorption tower A, which is lined with natural gas dehydration material, for dehydration treatment, thus completing the cycle.

5. The process for natural gas dehydration using a natural gas dehydration material according to claim 4, characterized in that, The pressure difference between the depressurized adsorption tower B and the pressurized adsorption tower A is ≥7.5MPa.

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