Molecular sieve for natural gas drying equipment and preparation process thereof

Abstract

The application relates to the technical field of molecular sieves, and particularly discloses a molecular sieve for a natural gas drying device and a preparation process thereof. The raw material of the molecular sieve comprises the following components in parts by weight: 50.0-50.8 parts of molecular sieve raw powder, 20.0-20.4 parts of attapulgite, 12-16 parts of phosphorous slag, 4.9-5.1 parts of a binder, 1.4-1.6 parts of a first filling powder and 9.5-9.7 parts of a second filling powder; the first filling powder comprises halloysite nanotubes. The application reduces the shrinkage deformation of the prefabricated pellets in the high-temperature activation process, improves the anti-pulverization performance of the molecular sieve, reduces the influence of the pulverization phenomenon on the service life of the molecular sieve, and is beneficial to the long-term use of the molecular sieve in the natural gas drying device.

Description

Technical Field

[0001] This application relates to the field of molecular sieve technology, and more specifically, to a molecular sieve for natural gas drying equipment and its preparation process. Background Technology

[0002] Natural gas is an ideal alternative energy source for vehicles, characterized by low cost, high efficiency, no pollution, and safe and convenient use. It is widely used in urban gas systems, especially as a residential fuel. Natural gas often contains moisture, so it needs to be dried to ensure safe use. Currently, commonly used natural gas drying equipment generally incorporates molecular sieve adsorbents. The working principle utilizes the adsorption properties of these adsorbents to dry the natural gas. Natural gas drying equipment operates at relatively high pressures; therefore, ceramic balls are typically placed at the inlet of the equipment to protect the molecular sieves during actual drying. However, even with this measure, pulverization of the molecular sieves within the drying equipment is frequently observed.

[0003] One related technology involves a molecular sieve whose raw materials include the following components: 50 parts molecular sieve powder, 20 parts clay, and 16 parts reinforcing binder; the clay is attapulgite clay, and the ratio of the average particle size of the clay to the average particle size of the molecular sieve powder is 1:13; the reinforcing binder includes the following components by weight: 5 parts acid-hydrolyzed starch, 8 parts etherified starch, 11 parts nano alumina, 14 parts nano silica, and 4 parts crack-resistant agent; the etherified starch is hydroxypropyl starch; the crack-resistant agent includes the following components by weight: 20 parts glass fiber powder and 14 parts lignin fiber powder. The preparation method of molecular sieve includes the following steps: (1) Molecular sieve raw powder, clay and reinforcing binder are put into a mixer and stirred for 40 minutes at a speed of 1000 rpm to fully mix and obtain premixed powder; (2) The premixed powder is put into a pelletizer and rotated at a speed of 25 rpm, and water mist is sprayed into the premixed powder to obtain pre-made pellets; (3) The pre-made pellets are put into a low temperature dehumidifier and removed 25% of the water by weight of the pre-made pellets at 250°C; (4) The pre-made pellets in step (3) are put into a high temperature activation machine and activated at 600°C to obtain molecular sieve with a water content (mass fraction) of 3%.

[0004] Regarding the aforementioned technologies, the inventors believe that although anti-cracking agents and reinforcing binders are added to the molecular sieves, the pre-made pellets still shrink to a certain extent during the high-temperature activation process in the preparation of the molecular sieves, leading to pulverization of the molecular sieves and affecting their service life. Summary of the Invention

[0005] In related technologies, pre-formed granules still shrink to some extent during high-temperature activation, leading to pulverization of the molecular sieve and affecting its service life. To improve this defect, this application provides a molecular sieve for natural gas drying equipment and its preparation process.

[0006] In a first aspect, this application provides a molecular sieve for a natural gas drying device, employing the following technical solution:

[0007] A molecular sieve for a natural gas drying device, wherein the raw material of the molecular sieve comprises the following components by weight: 50.0-50.8 parts of molecular sieve raw powder, 20.0-20.4 parts of attapulgite, 12-16 parts of phosphorus slag, 4.9-5.1 parts of binder, 1.4-1.6 parts of first filler powder, and 9.5-9.7 parts of second filler powder; the first filler powder comprises glass fiber powder and halloysite nanotubes mixed in a weight ratio of (2.4-2.8):1, and the second filler powder comprises nano-alumina and nano-silica, wherein the silicon-alumina ratio of the second filler powder is 1.8-2.0.

[0008] By adopting the above technical solution, this application adds phosphorus slag to the raw material of the molecular sieve and uses halloysite nanotubes and glass fiber powder together as the first filler powder. Phosphorus slag is a lean material; its addition reduces the plasticity of the molecular sieve raw material, hindering the shrinkage deformation of the preformed pellets. Simultaneously, because the phosphorus slag has undergone cold quenching and granulation, it possesses a certain amount of interconnected pores, promoting the evaporation and removal of moisture from the preformed pellets, and reducing shrinkage caused by moisture evaporation and increased surface tension of water. Halloysite nanotubes, with their nanoscale tubular structure, can both work with glass fiber powder to limit shrinkage deformation and work with phosphorus slag to promote the evaporation and removal of moisture from the preformed pellets. Therefore, by adding phosphorus slag and halloysite nanotubes, this application reduces the shrinkage deformation of the preformed pellets during high-temperature activation, improves the anti-pulverization performance of the molecular sieve, and reduces the impact of pulverization on the service life of the molecular sieve.

[0009] Preferably, in the first filler powder, glass fiber powder and halloysite nanotubes are mixed in a weight ratio of (2.4-2.6):1.

[0010] By adopting the above technical solution, this application has optimized the ratio of glass fiber powder and halloysite nanotubes, which helps to improve the anti-pulverization performance of molecular sieves.

[0011] Preferably, the second filler powder further comprises coal-based solid waste material, which includes chlorinated coal gangue powder or alkali-fused coal gangue powder. The chlorinated coal gangue powder is obtained by chlorinating and roasting coal gangue powder, and the alkali-fused coal gangue powder is obtained by acid washing and alkali fusion activation of chlorinated coal gangue powder. The weight of the coal-based solid waste material accounts for 5-18% of the total weight of the second filler powder.

[0012] By adopting the above technical solution, this application also prefers coal-based solid waste materials as the components of the second filler powder. The chlorinated coal gangue powder and alkali-fused coal gangue powder selected in this application both have interconnected pores, which can work together with halloysite nanotubes and phosphorus slag to promote the evaporation and removal of moisture inside the preformed pellets, reduce the shrinkage caused by moisture evaporation and increased surface tension of water, and help improve the anti-pulverization performance of molecular sieves.

[0013] Preferably, the chlorinated coal gangue powder is prepared according to the following method:

[0014] Coal gangue is crushed to obtain coal gangue powder. The coal gangue powder is added to ammonium chloride solution and mixed. Then, the mixture is roasted at 850-950℃ for 1-3 hours to obtain chlorinated coal gangue powder.

[0015] By adopting the above technical solution, this application has optimized the preparation method of chlorinated coal gangue powder, and the preparation of chlorinated coal gangue powder can be achieved by following the above method.

[0016] Preferably, the alkali-fused coal gangue powder is prepared according to the following method:

[0017] (1) Add chlorinated coal gangue powder to a 2-10 mol / L hydrochloric acid solution at a weight ratio of 1:(8-10), and perform acid washing at 120-200℃. After acid washing, cool, wash and dry to obtain acid-washed coal gangue powder for later use.

[0018] (2) Calcine the acid-washed coal gangue powder at 750-780℃ for 60-120 min, then mix the obtained calcined product with sodium carbonate at a ratio of 1:(0.6-1.2), and calcine at 800-820℃ for 90-120 min to obtain alkali-fused coal gangue powder.

[0019] By adopting the above technical solution, this application has optimized the preparation method of alkali-fused coal gangue powder. According to the above method, the coal gangue powder can be further activated on the basis of chlorination roasting, so that the alkali-fused coal gangue powder can play a better reinforcing effect in the molecular sieve and help improve the anti-pulverization performance of the molecular sieve.

[0020] Preferably, in step (1) of preparing the alkali-fused coal gangue powder, vermiculite powder and coal gangue powder are added together to an ammonium chloride solution and mixed, and then calcined at 900-950°C. The amount of vermiculite powder is 0.5-1.5% of the weight of the coal gangue powder.

[0021] By adopting the above technical solution, this application sets the roasting temperature above 900℃ and adds vermiculite powder. Under the above roasting conditions, vermiculite powder can generate liquid phase components, which improves the contribution of coal gangue powder to strength. This allows alkali-fused coal gangue powder to play a better reinforcing effect in molecular sieves, which helps to improve the anti-pulverization performance of molecular sieves.

[0022] Preferably, the coal-based solid waste material is alkali-fused coal gangue powder, and the weight of the coal-based solid waste material accounts for 12-18% of the total weight of the second filler powder.

[0023] By adopting the above technical solution, this application optimizes the amount of alkali-fused coal gangue powder used, which helps to improve the anti-pulverization performance of molecular sieves.

[0024] Preferably, the binder includes at least one of hydroxypropyl starch and acid-hydrolyzed starch, and the binder also includes silica sol and aluminum sol, wherein the sum of the weights of the silica sol and aluminum sol is 60-75% of the total weight of the binder, and the silica-alumina ratio of the silica sol and aluminum sol is 1.8-2.0.

[0025] By adopting the above technical solution, this application achieves the molding of molecular sieves by selecting at least one of hydroxypropyl starch and acid-hydrolyzed starch, along with silica sol and alumina sol, as binders. The mixing of silica sol and alumina sol forms a gel, which improves the adhesion between the components of the molecular sieve, helps increase its strength, and thus improves its resistance to pulverization.

[0026] Preferably, the molecular sieve has a particle size of 3-5 mm, and the weight ratio of particles with a particle size of 4-5 mm in the molecular sieve is 90%-100%. The strength of the molecular sieve is 150N-170N, the static water adsorption capacity of the molecular sieve is 23-24%, and the adsorption pore size of the molecular sieve is 0.37 nm.

[0027] By adopting the above technical solution, the molecular sieve of this application possesses excellent strength properties, which can be further improved by increasing the proportion of large-diameter particles through screening. Moreover, due to the strong static water adsorption capacity of the molecular sieve of this application, the dew point of the finished natural gas can be lowered to -60 to -70°C, thereby achieving an ideal drying effect. Furthermore, while the adsorption pore size of the molecular sieve of this application is insufficient to adsorb methane, it can still adsorb water molecules, which is beneficial for achieving an ideal deep drying effect.

[0028] Secondly, this application provides a process for preparing molecular sieves for natural gas drying equipment, which adopts the following technical solution.

[0029] A process for preparing molecular sieves for natural gas drying equipment includes the following steps:

[0030] (1) Molecular sieve raw powder, attapulgite clay, phosphorus slag, binder, first filler powder and second filler powder are mixed to obtain premixed powder;

[0031] (2) The premixed powder is put into a pelletizer for rotary granulation to obtain pre-made pellets;

[0032] (3) The pre-made pellets are baked and dehumidified, and then heated and activated at 500±20℃ to obtain molecular sieves.

[0033] By adopting the above technical solution, this application first prepared a premixed powder using molecular sieve raw powder, kaolin, phosphorus slag, binder, first filler powder, and second filler powder. Then, the premixed powder was granulated, and the obtained pre-formed pellets were heated and activated to obtain a molecular sieve for natural gas drying equipment with good anti-pulverization effect.

[0034] In summary, this application has the following beneficial effects:

[0035] 1. By adding phosphorus slag and halloysite nanotubes, this application reduces the shrinkage and deformation of pre-formed pellets during high-temperature activation, improves the anti-pulverization performance of molecular sieves, reduces the impact of pulverization on the service life of molecular sieves, and is beneficial to the long-term use of molecular sieves in natural gas drying equipment.

[0036] 2. In this application, coal-based solid waste materials are preferred as the components of the second filler powder. Specifically, the chlorinated coal gangue powder and alkali-fused coal gangue powder selected both have interconnected pores inside, which can work together with halloysite nanotubes and phosphorus slag to promote the evaporation and removal of moisture inside the preformed pellets, reduce the shrinkage caused by moisture evaporation and increased surface tension of water, and help improve the anti-pulverization performance of the molecular sieve. Detailed Implementation

[0037] The present application will be further described in detail below with reference to the embodiments, preparation examples and comparative examples. The raw materials involved in the present application can all be obtained commercially.

[0038] Examples of preparation of chlorinated coal gangue powder and alkali-fused coal gangue powder

[0039] The following explanation uses Preparation Example 1 as an example.

[0040] Preparation Example 1

[0041] In this preparation example, chlorinated coal gangue powder and alkali-fused coal gangue powder are prepared according to the following method:

[0042] (1) Coal gangue with a silicon-to-aluminum ratio (molar ratio) of 6.4 was crushed to obtain 300-mesh coal gangue powder. The coal gangue powder was added to ammonium chloride solution and mixed. The mixture was then roasted at 850℃ (referred to as roasting temperature in Table 1) for 1 hour (referred to as roasting time in Table 1) to obtain chlorinated coal gangue powder. The chlorinated coal gangue powder was added to a 2mol / L hydrochloric acid solution (referred to as hydrochloric acid concentration in Table 1) at a weight ratio of 1:8 (referred to as solid-liquid ratio in Table 1). The mixture was then acid-washed at 120℃ (referred to as acid washing temperature in Table 1). After acid washing, the mixture was cooled, washed and dried to obtain acid-washed coal gangue powder for later use.

[0043] (2) The acid-washed coal gangue powder was calcined at 750℃ (referred to as the first calcination temperature in Table 1) for 60 min (referred to as the first calcination time in Table 1). Then, the calcined product was mixed with sodium carbonate at a ratio of 1:0.6 (referred to as the compound ratio in Table 1) and calcined at 800℃ (referred to as the second calcination temperature in Table 1) for 90 min (referred to as the second calcination time in Table 1) to obtain alkali-fused coal gangue powder.

[0044] As shown in Table 1, the difference between Preparation Examples 1-5 lies in the different processing parameters of chlorinated coal gangue powder and alkali-fused coal gangue powder.

[0045] Table 1 Processing parameters of chloride-treated coal gangue powder and alkali-fused coal gangue powder

[0046] sample Preparation Example 1 Preparation Example 2 Preparation Example 3 Preparation Example 4 Preparation Example 5 Calcination temperature / °C 850 860 870 880 890 Calcination time / h 1 2 2 3 3 solid-liquid ratio 1:8 1:9 1:9 1:10 1:10 Hydrochloric acid concentration (mol / L) 2 4 6 8 10 Pickling temperature / ℃ 120 140 160 180 200 Initial calcination temperature / °C 750 755 762 770 780 First calcination time / min 60 75 90 100 120 Compound ratio 1:0.6 1:0.7 1:0.9 1:1.0 1:1.2 Secondary calcination temperature / ℃ 800 805 810 815 820 Secondary calcination time / min 90 97 104 111 120

[0047] Preparation Example 6

[0048] The difference between this preparation example and preparation example 5 is that in step (1) of preparing alkali-fused coal gangue powder, vermiculite powder and coal gangue powder are added together to ammonium chloride solution and mixed, and then roasted at 900°C. The amount of vermiculite powder is 0.5% of the weight of coal gangue powder (referred to as vermiculite powder percentage in Table 2).

[0049] As shown in Table 2, the differences between preparation examples 6-10 are the calcination temperature and the proportion of vermiculite powder.

[0050] Table 2. Calcination temperature and vermiculite powder ratio

[0051] sample Calcination temperature / °C Vermiculite powder percentage Preparation Example 6 900 0.5 Preparation Example 7 912 0.8 Preparation Example 8 925 1.0 Preparation Example 9 936 1.2 Preparation Example 10 950 1.5

[0052] Example

[0053] Examples 1-5

[0054] The following description uses Example 1 as an example.

[0055] Example 1

[0056] This embodiment provides a molecular sieve for a natural gas drying equipment. The raw materials include the following components: 50.0 kg of molecular sieve powder, 20.0 kg of attapulgite, 12 kg of phosphorus slag (300 mesh), 4.9 kg of binder, 1.4 kg of first filler powder, and 9.5 kg of second filler powder. The ratio of the average particle size of the attapulgite to the average particle size of the molecular sieve powder is 1:13. The binder is a mixture of acid-hydrolyzed starch and etherified starch in a weight ratio of 5:8. The acid-hydrolyzed starch meets the requirements of GB 29928-2013, and the etherified starch is hydroxypropyl starch (CAS: 9049-76-7). The first filler powder is a mixture of glass fiber powder (300 mesh) and halloysite nanotubes in a weight ratio of 2.8:1. The second filler powder is a mixture of nano-alumina and nano-silica, and the silicon-to-alumina ratio (molar ratio) of the second filler powder is 1.8.

[0057] The partial mineral composition of the phosphorus slag (based on the detected oxide content) is as follows: silicon dioxide 38.24%, iron oxide 0.82%, aluminum oxide 4.65%, calcium oxide 48.86%, phosphorus pentoxide 2.27%, and magnesium oxide 1.04%.

[0058] The partial mineral composition of halloysite nanotubes (based on the detected oxide content) is as follows: silicon dioxide 41.82%, aluminum oxide 33.69%, magnesium oxide 3.37%, calcium oxide 0.79%, iron oxide 0.14%, sodium oxide 0.27%, and potassium oxide 0.08%.

[0059] In this embodiment, the molecular sieve for the natural gas drying equipment is prepared according to the following steps:

[0060] (1) Molecular sieve raw powder, attapulgite clay, phosphorus slag, binder, first filler powder and second filler powder are stirred and mixed at a rate of 900 r / min for 45 min to obtain premixed powder.

[0061] (2) The premixed powder is placed in a pelletizer and granulated at a speed of 22 r / min. Water mist is sprayed into the premixed powder in the pelletizing process. Pre-made pellets are obtained after 5 hours.

[0062] (3) The pre-made pellets are baked at 250℃ to remove moisture equivalent to 20% of the total weight of the pre-made pellets. Then, the pre-made pellets are heated and activated at 480℃ for 4 hours to obtain molecular sieves. The sieves are screened in the particle size range of 3-5mm so that the molecular sieve particles with a particle size between 4-5mm account for 90% of the weight and the molecular sieve particles with a particle size between 3-4mm account for 10% of the weight, which is the final product.

[0063] As shown in Table 3, the main differences between Examples 1-5 are the raw material ratio of the molecular sieve used in the natural gas drying equipment and the activation temperature of the pre-made pellets.

[0064] Table 3. Raw material ratios and activation temperatures of molecular sieves for natural gas drying equipment.

[0065]

[0066] Examples 5-9

[0067] As shown in Table 4, the difference between Example 5 and Examples 6-9 is that the glass fiber powder and halloysite nanotubes are mixed in different weight ratios.

[0068] Table 4 Mixing ratio of glass fiber powder and halloysite nanotubes

[0069] sample Example 5 Example 6 Example 7 Example 8 Example 9 Mixing ratio 2.8:1 2.7:1 2.6:1 2.5:1 2.4:1

[0070] Example 10

[0071] The difference between this embodiment and embodiment 9 is that the second filler powder also includes coal-based solid waste material. The coal-based solid waste material is the chlorinated coal gangue powder of preparation example 1, and the weight of the coal-based solid waste material accounts for 5% of the total weight of the second filler powder.

[0072] Example 11

[0073] The difference between this embodiment and Embodiment 10 is that the coal-based solid waste material used is the alkali-fused coal gangue powder prepared in Embodiment 1.

[0074] As shown in Table 5, the difference between Examples 11-20 is that the alkali-fused coal gangue powder was prepared according to different preparation methods.

[0075] Table 5 Examples of preparation of alkali-fused coal gangue powder

[0076]

[0077]

[0078] Examples 20-24

[0079] As shown in Table 6, the difference between embodiments 20-24 is that the weight of the coal-based solid waste material accounts for a different percentage of the total weight of the second filling powder (hereinafter referred to as the coal-based solid waste percentage).

[0080] Table 6. Proportion of Coal-based Solid Waste

[0081] sample Coal-based solid waste percentage Example 20 5 Example 21 9 Example 22 12 Example 23 16 Example 24 18

[0082] Example 25

[0083] The difference between this embodiment and embodiment 9 is that the binder includes silica sol and aluminum sol, the silica-alumina ratio of silica sol and aluminum sol is 1.8, and the sum of the weights of silica sol and aluminum sol is 60% of the total weight of the binder.

[0084] As shown in Table 7, the differences between Examples 25-29 are that the silicon-to-aluminum ratio between the silica sol and the aluminum sol is different, and the percentage of the sum of the weights of the silica sol and the aluminum sol to the total weight of the binder (hereinafter referred to as the sol percentage) is different.

[0085] Table 7. Silica-to-alumina ratio and sol percentage between silica sol and alumina sol.

[0086] sample Silicon-to-aluminum ratio Sol percentage / % Example 25 1.8 60 Example 26 1.9 63 Example 27 1.9 67 Example 28 2.0 70 Example 29 2.0 75

[0087] Comparative Example

[0088] Comparative Example 1

[0089] This comparative example provides a molecular sieve, the raw materials of which include the following components: 50 kg of molecular sieve raw powder (4A grade), 20 kg of attapulgite clay, and 16 kg of reinforcing binder; the ratio of the average particle size of the attapulgite clay to the average particle size of the molecular sieve raw powder is 1:13; the reinforcing binder is prepared by acid-hydrolyzed starch, etherified starch, nano-alumina, nano-silica, and anti-cracking agent in a weight ratio of 5:8:11:14:4; the etherified starch is hydroxypropyl starch; the anti-cracking agent is prepared by glass fiber powder (300 mesh) and lignin fiber powder (325 mesh) in a weight ratio of 10:7. The acid-hydrolyzed starch meets the requirements of GB 29928-2013, and the etherified starch is hydroxypropyl starch (CAS:9049-76-7).

[0090] In this comparative example, the preparation method of the molecular sieve includes the following steps:

[0091] (1) Place molecular sieve raw powder, clay and reinforcing binder into a mixer and stir at 900 r / min for 45 min to obtain premixed powder;

[0092] (2) The premixed powder is placed in the pelletizer, the pelletizer is rotated at a speed of 22r / min, and water mist is sprayed into the premixed powder. After 5 hours, pre-made pellets are obtained.

[0093] (3) Place the pre-made pellets into a low-temperature dehumidifier and remove 20% of the water by weight of the pre-made pellets at 250°C.

[0094] (4) Place the pre-made pellets from step (3) into a high-temperature activation machine and activate them at 480°C for 4 hours to obtain a molecular sieve. Screen the particles in the 3-5 mm particle size range so that the molecular sieve particles with a particle size between 4-5 mm account for 90% of the weight and the molecular sieve particles with a particle size between 3-4 mm account for 10% of the weight, which is the final product.

[0095] Comparative Example 2

[0096] The difference between this comparative example and Example 1 is that halloysite nanotubes were replaced with the same weight of glass fiber powder.

[0097] Comparative Example 3

[0098] The difference between this comparative example and Example 1 is that the raw material components of the molecular sieve do not include phosphorus slag powder.

[0099] Performance testing methods

[0100] I. Dust shedding test

[0101] Referring to the description in "HG / T 5336-2018 Method for Determination of Molecular Sieve Shedding Degree", the shedding degree of the molecular sieves in each example and comparative example was determined. The result of each example and comparative example was the average value of 30 samples, and this average value was recorded as the final measured shedding degree. Using the shedding degree of Comparative Example 1 as the benchmark, the ratio between the shedding degree of each example and comparative example and the shedding degree of Comparative Example 1 was calculated, and this ratio was recorded as the relative shedding degree. The results are shown in Table 8.

[0102] II. Wear Rate Measurement

[0103] Referring to the description in HG / T 2524-2010, the wear rate of the molecular sieves in each example and comparative example was determined. The result for each example and comparative example was the average value of 30 samples, and this average value was recorded as the final measured wear rate. Using the wear rate of Comparative Example 1 as a benchmark, the ratio between the wear rate of each example and comparative example and the wear rate of Comparative Example 1 was calculated, and this ratio was recorded as the relative wear rate. The results are shown in Table 8.

[0104] Table 8. Relative dusting rate and relative abrasion rate

[0105]

[0106] Based on Examples 1-5 and Comparative Example 1, and in conjunction with Table 4, it can be seen that the relative dust shedding and relative abrasion rate measured in Examples 1-5 are lower than those in Comparative Example 1. This indicates that by adding phosphorus slag and halloysite nanotubes, this application reduces the shrinkage deformation of pre-formed pellets during high-temperature activation, improves the anti-pulverization performance of the molecular sieve, and reduces the impact of pulverization on the service life of the molecular sieve.

[0107] As can be seen from Example 1 and Comparative Examples 1-3 and Table 8, when either phosphorus slag or halloysite nanotubes are missing from the raw materials of the molecular sieve, the anti-pulverization performance of the molecular sieve will be greatly affected.

[0108] As can be seen from Examples 5 and 6-9 and Table 8, when glass fiber powder and halloysite nanotubes are mixed in a weight ratio of (2.4-2.6):1, the molecular sieve exhibits better anti-pulverization properties, resulting in less dust falling off during processing and lower losses during abrasion.

[0109] As can be seen from Examples 9, 10-11 and Table 8, when the second filler powder contains the two coal-based solid waste materials specified in this application, the anti-pulverization performance of the molecular sieve can be improved to a certain extent.

[0110] As can be seen from Examples 10, 11-15, and Table 8, alkali-fused coal gangue powder has a better effect on improving the anti-pulverization performance of molecular sieves compared to chlorinated coal gangue powder. Furthermore, as can be seen from Examples 15, 16-20, and Table 8, adding vermiculite powder during the preparation of chlorinated coal gangue powder can further improve the anti-pulverization performance of molecular sieves with the resulting alkali-fused coal gangue powder.

[0111] As can be seen from Examples 20-24 and Table 8, when alkali-fused coal gangue powder is used as the coal-based solid waste material, the molecular sieve exhibits better anti-pulverization performance when the weight of the coal-based solid waste material accounts for 12-18% of the total weight of the second filler powder.

[0112] As can be seen from Examples 24, 25-29 and Table 8, by setting 60-75% of the total weight of the binder as silica sol and making the silica-alumina ratio of silica sol to alumina sol 1.8-2.0, the anti-pulverization performance of molecular sieves can be improved to a certain extent.

[0113] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A molecular sieve for a natural gas drying device, characterized in that, The raw materials of the molecular sieve, by weight, include the following components: 50.0-50.8 parts of molecular sieve powder, 20.0-20.4 parts of attapulgite, 12-16 parts of phosphorus slag, 4.9-5.1 parts of binder, 1.4-1.6 parts of first filler powder, and 9.5-9.7 parts of second filler powder; the first filler powder consists of glass fiber powder and halloysite nanotubes mixed in a weight ratio of (2.4-2.8):1, and the second filler powder consists of nano-alumina and nano-silica, with a silica-alumina ratio of 1.8-2.0; The preparation process of the molecular sieve for the natural gas drying equipment includes the following steps: (1) Molecular sieve raw powder, attapulgite clay, phosphorus slag, binder, first filler powder and second filler powder are mixed to obtain premixed powder; (2) The premixed powder is put into a pelletizer and rotated to granulate to obtain pre-made pellets; (3) The pre-made pellets are baked and dehumidified, and then heated and activated at 500±20℃ to obtain molecular sieves.

2. The molecular sieve for natural gas drying equipment according to claim 1, characterized in that, In the first filler powder, glass fiber powder and halloysite nanotubes are mixed in a weight ratio of (2.4-2.6):

1.

3. The molecular sieve for natural gas drying equipment according to claim 1, characterized in that, The second filler powder also includes coal-based solid waste materials, which include chlorinated coal gangue powder or alkali-fused coal gangue powder. The chlorinated coal gangue powder is obtained by chlorinating and roasting coal gangue powder, and the alkali-fused coal gangue powder is obtained by acid washing and alkali fusion activation of chlorinated coal gangue powder. The weight of the coal-based solid waste materials accounts for 5-18% of the total weight of the second filler powder.

4. The molecular sieve for natural gas drying equipment according to claim 3, characterized in that, The chlorinated coal gangue powder is prepared according to the following method: Coal gangue is crushed to obtain coal gangue powder. The coal gangue powder is added to ammonium chloride solution and mixed. Then, the mixture is roasted at 850-950℃ for 1-3 hours to obtain chlorinated coal gangue powder.

5. The molecular sieve for natural gas drying equipment according to claim 3, characterized in that, The alkali-fused coal gangue powder is prepared according to the following method: (1) Add chlorinated coal gangue powder to a 2-10 mol / L hydrochloric acid solution at a weight ratio of 1:(8-10), and perform acid washing at 120-200℃. After acid washing, cool, wash and dry to obtain acid-washed coal gangue powder for later use. (2) Calcine the acid-washed coal gangue powder at 750-780℃ for 60-120 min, then mix the obtained calcined product with sodium carbonate at a ratio of 1:(0.6-1.2), and calcine at 800-820℃ for 90-120 min to obtain alkali-fused coal gangue powder.

6. The molecular sieve for natural gas drying equipment according to claim 5, characterized in that, In step (1) of preparing the alkali-fused coal gangue powder, vermiculite powder and coal gangue powder are added together to ammonium chloride solution and mixed, and then calcined at 900-950℃. The amount of vermiculite powder is 0.5-1.5% of the weight of coal gangue powder.

7. The molecular sieve for natural gas drying equipment according to claim 6, characterized in that, The coal-based solid waste material is selected from alkali-fused coal gangue powder, and the weight of the coal-based solid waste material accounts for 12-18% of the total weight of the second filler powder.

8. The molecular sieve for natural gas drying equipment according to claim 1, characterized in that, The binder includes at least one of hydroxypropyl starch and acid-hydrolyzed starch. The binder also includes silica sol and aluminum sol, the sum of the weights of the silica sol and aluminum sol being 60-75% of the total weight of the binder, and the silica-alumina ratio of the silica sol and aluminum sol being 1.8-2.

0.

9. The molecular sieve for natural gas drying equipment according to claim 1, characterized in that, The molecular sieve has a particle size of 3-5 mm, and the weight ratio of particles with a particle size of 4-5 mm in the molecular sieve is 90%-100%. The strength of the molecular sieve is 150N-170N, the static water adsorption capacity of the molecular sieve is 23-24%, and the adsorption pore size of the molecular sieve is 0.37 nm.

10. The preparation process of molecular sieves for natural gas drying equipment according to any one of claims 1-9, characterized in that, Includes the following steps: (1) Molecular sieve raw powder, attapulgite clay, phosphorus slag, binder, first filler powder and second filler powder are mixed to obtain premixed powder; (2) The premixed powder is put into a pelletizer and rotated to granulate to obtain pre-made pellets; (3) The pre-made pellets are baked and dehumidified, and then heated and activated at 500±20℃ to obtain molecular sieves.

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