Y-type molecular sieve for small crystal grains and preparation method of Y-type molecular sieve
By controlling the proportion of raw materials and the preparation process, the industrialization problem of small-crystal Y-type molecular sieves was solved, and low-cost, high-efficiency catalytic performance improvement was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUNAN TIANYI NEW MATERIAL CO LTD
- Filing Date
- 2026-03-16
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies make it difficult to mass-produce small-crystal Y-type molecular sieves using low-cost and simple processes, and the high-speed equipment requirements are stringent, leading to difficulties in industrialization.
Using sodium aluminate, sodium silicate, sodium hydroxide and deionized water in a specific ratio as raw materials, and by controlling the dropping rate and temperature, small-crystal Y-type molecular sieves are prepared, including static crystallization and rinsing steps, to ensure that the particle size is controlled at around 300 nm.
A low-cost, simplified process was developed to produce small-crystal Y-type molecular sieves with large specific surface area and mesoporous surface area, making them suitable for macromolecular reactions and improving catalytic efficiency and yield.
Smart Images
Figure CN122010137A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of molecular sieve technology, and in particular to a Y-type molecular sieve for small crystals and its preparation method. Background Technology
[0002] Y-type molecular sieves are artificially synthesized octahedral zeolite (FAU) structures capable of withstanding the impact of high-temperature steam during catalytic cracking regeneration. The fewer aluminum atoms, the lower the negative charge density of the framework, the weaker the hydrophilicity, the increased acid strength, and the framework collapse temperature above 800℃. Subsequently, by introducing rare earth ions, its structural stability and acidity were significantly improved, increasing the yield of catalytic cracked gasoline by 10%–20%. Further high-temperature hydrothermal or chemical treatment to remove framework aluminum creates secondary pores, enabling faster mass transfer in heavy oil macromolecular cracking, representing a further technological breakthrough.
[0003] Y-type molecular sieves have been a core component of fluid catalytic cracking (FCC) and hydrocracking catalysts since their industrialization. As crude oil becomes increasingly heavy and of lower quality, the large gum and asphaltenes in the feedstock have difficulty entering the long channels inside traditional micron-sized crystals (1~6μm). The diffusion paths of reactants to active centers and products to the outside are long, which easily leads to secondary cracking and carbon deposition, forcing the unit to operate at high temperatures and regenerate frequently, resulting in a decrease in economic efficiency and clean oil yield.
[0004] Studies have found that the physicochemical properties undergo significant nonlinear changes after the grain size is reduced. The accumulation of small-grained molecular sieves generates abundant intergranular mesopores, providing rapid pathways for macromolecules. Simultaneously, the increased number of directly exposed active sites on the outer surface allows macromolecules to react at the inlet. Smaller grains shorten diffusion time, significantly inhibiting hydrogen transfer reactions and improving olefin yield. During rapid nucleation and growth, smaller grains tend to generate more defects in the framework, often resulting in more exposed acidic centers, which is more beneficial for subsequent modification.
[0005] In the prior art, Chinese patent application CN121536943A discloses a method for synthesizing nanosheet-like NaY molecular sieves. This method utilizes high-speed shearing to mix and disperse materials, synthesizing nanosheet-like NaY molecular sieves without a template agent. However, this method places strict requirements on the performance of high-speed equipment, and the equipment failure rate and long-term stable operation are bottlenecks limiting industrialization. Furthermore, the size of the molecular sieves synthesized by this method offers limited advantages in subsequent catalytic processes.
[0006] Given the unique characteristics and performance advantages of small-crystal molecular sieves, developing a low-cost, simple production process that can be industrialized in large quantities is of great significance. Summary of the Invention
[0007] The purpose of this invention is to develop a low-cost, simple production process for preparing small-crystal Y-type molecular sieves by making deep use of small-crystal seed crystals.
[0008] The technical solution adopted by this invention to solve the technical problem is: A seed crystal for the preparation of small-grained Y-type molecular sieves comprises sodium aluminate, sodium silicate, sodium hydroxide, and deionized water. The molar ratio of silicon dioxide to aluminum oxide in the raw materials is 15.5~16.5:1, the molar ratio of sodium oxide to silicon dioxide is 0.75~0.79:1, and the molar ratio of water to silicon dioxide is 13.5~13.9:1.
[0009] Furthermore: the molar ratio of silicon dioxide to aluminum oxide in the raw materials is 16:1, the molar ratio of sodium oxide to silicon dioxide in the raw materials is 0.78:1, and the molar ratio of water molecules to silicon dioxide in the raw materials is 13.75:1.
[0010] Furthermore: the concentration of the sodium aluminate solution is between 18.5% and 27%, the concentration of the sodium silicate solution is above 27%, and the concentration of the sodium hydroxide solution is greater than 48%.
[0011] The purpose of this invention is to prepare a small-grained Y-type molecular sieve, the method of which includes the following steps: Calculate the required mass of various raw materials according to a certain ratio based on the raw material analysis indicators; Sodium aluminate solution was added dropwise to sodium silicate solution through a separatory funnel, and the dropping rate was controlled to ensure good fluidity of the reaction system. Add aluminum sulfate and some deionized water to the reaction system, stir well and heat to 96°C; The prepared small crystal seeds were added to the reaction system, and the calculated amount of deionized water was added. The reaction system was further heated to 100℃ and statically crystallized at ambient pressure for 40~50h at 100±2℃. When the reaction system is cooled to 50~70℃, solid-liquid separation is performed on a Buchner funnel. At the same time, the filter cake is washed with deionized water at 60~70℃ and dried to obtain the finished product of small-crystal Y-type molecular sieve.
[0012] Furthermore, the amount of seed crystals used is 0.5% to 4% of the total mass of the feed.
[0013] Furthermore: the rinsing water volume is not less than 1 volume of deionized water for rinsing, and the rinsed filter cake is dried in an environment not exceeding 250°C.
[0014] Furthermore: the raw materials added in the preparation method have a molar ratio of silicon dioxide to aluminum oxide of 8.35~8.40:1, a molar ratio of sodium oxide to silicon dioxide of 0.50~0.52:1, and a molar ratio of water to silicon dioxide of 23~24:1.
[0015] Furthermore, the ratio of raw materials added in the preparation method is 0.51:1 in molar ratio of sodium oxide to silicon dioxide.
[0016] Furthermore: the BET specific surface area of the molecular sieve is 789~808 m². 2 / g, the mesoporous specific surface area of the molecular sieve is 39~50m². 2 / g, wherein the crystallinity of the molecular sieve is 55.3%~74.7%, and the silica-alumina ratio of the molecular sieve is 4.20~5.08.
[0017] The technical effects achieved by this invention are: In this invention, the prerequisite is the prior preparation of highly efficient seed crystals, i.e., highly active directing agents, which are then aged at low temperature (23~25℃) to generate a large number of primary structural units, thereby triggering nucleation in the early stages of molecular sieve synthesis. The product particle size can be stably controlled at around 300nm. Its production characteristics include low production cost, a simple process, environmental friendliness (no high ammonia nitrogen wastewater generated), and a large specific surface area (800m²). 2 / g), large mesoporous surface (40m 2 / g). Attached Figure Description
[0018] Figure 1 This is a scanning electron microscope image of Embodiment 2 of the present invention.
[0019] Figure 2 This is a scanning electron microscope image of Embodiment 3 of the present invention.
[0020] Figure 3 This is a scanning electron microscope image of Embodiment 4 of the present invention.
[0021] Figure 4 This is a scanning electron microscope image of Embodiment 5 of the present invention.
[0022] Figure 5 This is a scanning electron microscope image of Embodiment 6 of the present invention.
[0023] Figure 6 This is a scanning electron microscope image of Embodiment 7 of the present invention. Detailed Implementation
[0024] The present invention will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.
[0025] A seed crystal for the preparation of small-grained Y-type molecular sieves comprises sodium aluminate, sodium silicate, sodium hydroxide, and deionized water. The molar ratio of silicon dioxide to aluminum oxide in the raw materials is 15.5-16.5:1, the molar ratio of sodium oxide to silicon dioxide is 0.75-0.79:1, and the molar ratio of water to silicon dioxide is 13.5-13.9:1.
[0026] The preferred scheme is: the molar ratio of silicon dioxide to aluminum oxide in the raw materials is 16:1, the molar ratio of sodium oxide to silicon dioxide in the raw materials is 0.78:1, and the molar ratio of water molecules to silicon dioxide in the raw materials is 13.75:1.
[0027] The concentration of the sodium aluminate solution is between 18.5% and 27%, the concentration of the sodium silicate solution is above 27%, and the concentration of the sodium hydroxide solution is greater than 48%.
[0028] The preparation method of the above-mentioned seed crystals includes the following steps: Slowly add a liquid alkali solution with a mass fraction higher than 48% to a sodium silicate solution with a mass fraction of 27% or more. Set up a cold water bath for the reaction, start stirring, and when the system temperature is below 25°C, slowly add a 27% sodium aluminate solution dropwise through a separatory funnel, controlling the reaction temperature at 23-25°C. Add deionized water according to the calculated amount, and stir until homogeneous. After stopping stirring, let it stand at 27-28°C for at least 2 weeks to obtain a milky white liquid seed crystal.
[0029] Based on the above-mentioned seed crystals, a small-crystal Y-type molecular sieve is prepared by mixing the seed crystals with sodium aluminate, sodium silicate, aluminum sulfate, and deionized water, reacting them, statically crystallizing them for a period of time, cooling them down, filtering them, and then washing and drying the filter cake to obtain the finished small-crystal molecular sieve.
[0030] The preparation method of the above-mentioned small-crystal Y-type molecular sieve includes the following steps: A 27% sodium aluminate solution was added dropwise to a 27% sodium silicate solution using a separatory funnel, with the dropping rate controlled to ensure good fluidity of the reaction system. Add 27% aluminum sulfate and some deionized water to the reaction system, stir well and heat to 96℃; Add seed crystals at 2% of the total mass of the feed to the reaction system, and replenish the calculated amount of deionized water (the molar ratio of water to silicon dioxide is 23.7). The reaction system was further heated to 100℃ and statically crystallized at ambient pressure for 40~50h at 100±2℃. When the reaction system is cooled to 50~70℃, solid-liquid separation is performed on a Buchner funnel. At the same time, the filter cake is washed with deionized water at 60~70℃ and dried to obtain the finished product of small-crystal Y-type molecular sieve.
[0031] The raw materials added in the preparation method have the following molar ratios: silicon dioxide to aluminum oxide is 8.35~8.40:1; sodium oxide to silicon dioxide is 0.50~0.52:1; and water to silicon dioxide is 23~24:1.
[0032] The preferred method is that the ratio of the raw materials added in the preparation method is that the molar ratio of sodium oxide to silicon dioxide is 0.51:1.
[0033] After testing, the BET specific surface area of the molecular sieve was found to be 789~808 m². 2 / g, the mesoporous specific surface area of the molecular sieve is 39~50m². 2 / g, the crystallinity of the molecular sieve is 55.3%~74.7%, and the silica-alumina ratio (SAR) of the molecular sieve is 4.20~5.08.
[0034] Example 1 Weigh 48.06g of water glass, zero the electronic scale, and slowly add 13.57g of low-biased water glass to the beaker containing the water glass. Zero the electronic scale again, then add 6.93g of aluminum sulfate. Remove the beaker and start stirring. After mixing evenly, start heating to 96℃. Add 0.5g of new seed crystals that have been stirred evenly and weighed. Then weigh 21.03g of chemical water to rinse the container after weighing the seed crystals and pour it all into the beaker. Stir evenly again. Transfer all the material in the beaker into the lining of the hydrothermal synthesis reactor and cover it. Let it stand and age for 40 hours. Then remove the synthesis reactor, filter, wash with water, and dry to obtain the finished product.
[0035] Test results: Crystallinity 64.8%, unit cell 24.79, SAR 4.20.
[0036] The above experimental feed ratios are as follows: the molar ratio of silicon dioxide to aluminum oxide is 8.38:1, the molar ratio of sodium oxide to silicon dioxide is 0.51:1, the molar ratio of water to silicon dioxide is 23.74:1, and the amount of seed crystals added is 0.5%.
[0037] Example 2
[0038] Weigh 48.06g of water glass, zero the electronic scale, and slowly add 13.57g of low-biased water glass to the beaker containing the water glass. Zero the electronic scale again, then add 6.93g of aluminum sulfate. Remove the beaker and start stirring. After mixing evenly, start heating to 96℃. Add 0.5g of new seed crystals that have been stirred evenly and weighed. Then weigh 21.03g of chemical water to rinse the container after weighing the seed crystals and pour it all into the beaker. Stir evenly again. Transfer all the material in the beaker into the lining of the hydrothermal synthesis reactor and cover it. Let it stand and age for 40 hours. Then remove the synthesis reactor, filter, wash with water, and dry to obtain the finished product.
[0039] Test results: Crystallinity 55.3%, unit cell 24.81, SAR 4.32.
[0040] The above experimental feed ratios are as follows: the molar ratio of silicon dioxide to aluminum oxide is 8.38:1, the molar ratio of sodium oxide to silicon dioxide is 0.51:1, the molar ratio of water to silicon dioxide is 23.74:1, and the amount of seed crystals added is 2.0%.
[0041] Example 3
[0042] Weigh 955.00g of water glass and place it on an electric heating furnace to start stirring. Then, slowly add 252.91g of low-absorption precipitate to the beaker containing the water glass through a separatory funnel. During the dropwise addition, add 389.64g of chemical water. After the addition is complete, add 175.19g of aluminum sulfate through another separatory funnel. After mixing evenly, start heating to 96℃. Add 35.45g of new seed crystals that have been stirred evenly and weighed. After stirring evenly again, transfer all the material in the beaker to a synthesis reactor and cover it. Let it stand and age at 100±2℃ for 40h. After that, remove the synthesis reactor, filter, wash with water, and dry to obtain the finished product.
[0043] Test results: Crystallinity 74.3%, unit cell 24.69, SAR 4.5.
[0044] The above experimental feed ratios are as follows: the molar ratio of silicon dioxide to aluminum oxide is 8.38:1, the molar ratio of sodium oxide to silicon dioxide is 0.51:1, the molar ratio of water to silicon dioxide is 23.74:1, and the amount of seed crystals added is 2.0%.
[0045] Example 4
[0046] Weigh 933.4g of water glass and place it on an electric heating furnace to start stirring. Then, slowly add 226.67g of low-polarity precipitate to the beaker containing the water glass through a separatory funnel. During the dropwise addition, add 371.96g of chemical water. After the addition is complete, add 212.69g of aluminum sulfate through another separatory funnel. After mixing evenly, start heating to 96℃. Add 69.79g of new seed crystals that have been stirred evenly and weighed. After stirring evenly again, transfer all the material in the beaker to a synthesis reactor and cover it. Let it stand and age at 100±2℃ for 40h. After that, remove the synthesis reactor, filter, wash with water, and dry to obtain the finished product.
[0047] Test results: Crystallinity 65.8%, cell size 24.71, SAR 5.0.
[0048] The above experimental feed ratios are as follows: the molar ratio of silicon dioxide to aluminum oxide is 8.38:1, the molar ratio of sodium oxide to silicon dioxide is 0.51:1, the molar ratio of water to silicon dioxide is 23.74:1, and the amount of seed crystals added is 4.0%.
[0049] Example 5
[0050] Weigh 961.2g of water glass and pour it into a beaker. Then weigh 368.86g of chemical water and add it to the beaker. After stirring evenly, slowly add 256.87g of low-impact chemical solution to the beaker containing water glass through a separatory funnel. Then add 197.32g of aluminum sulfate solution through another separatory funnel. After mixing evenly, record the liquid level in the beaker. Then start heating to 96℃. Add chemical water to the marked liquid level and heat again to 96℃. Add 35.69g of new seed crystals that have been stirred evenly and weighed. After stirring evenly again, transfer all the material in the beaker into a stainless steel synthesis reactor and seal it. Let it stand and age at 100±2℃ for 40h. Then remove the synthesis reactor, filter, wash with water, and dry to obtain the finished product.
[0051] Test results: Crystallinity 74.4%, cell size 24.69, SAR 5.08, specific surface area 808 m² 2 / g, pore volume 0.47ml / g, mesoporous specific surface area 44m² 2 / g, mesoporous pore volume 0.074ml / g.
[0052] The above experimental feed ratios are as follows: the molar ratio of silicon dioxide to aluminum oxide is 8.38:1, the molar ratio of sodium oxide to silicon dioxide is 0.51:1, the molar ratio of water to silicon dioxide is 23.71:1, and the amount of seed crystals added is 2.0%.
[0053] Example 6
[0054] Weigh 961.2g of water glass and pour it into a beaker. Then weigh 368.86g of chemical water and add it to the beaker. After stirring evenly, slowly add 256.87g of low-absorption precipitate to the beaker containing water glass through a separatory funnel. Then add 197.32g of aluminum sulfate solution through another separatory funnel. After mixing evenly, record the liquid level in the beaker. Then start heating to 96℃, add chemical water to the marked liquid level, heat again to 96℃, add 35.69g of new seed crystals that have been stirred evenly and weighed, and stir evenly again. Transfer all the material in the beaker to a stainless steel synthesis reactor and seal it. Let it stand and age for 50h at 100±2℃. After that, remove the synthesis reactor, filter, wash with water, and dry to obtain the finished product.
[0055] Test results: Crystallinity 71.3%, unit cell size 24.71, SAR 5.04, specific surface area 789 m² 2 / g, pore volume 0.45ml / g, mesoporous specific surface area 39m² 2 / g, mesoporous pore volume 0.073ml / g.
[0056] The above experimental feed ratios are as follows: the molar ratio of silicon dioxide to aluminum oxide is 8.38:1, the molar ratio of sodium oxide to silicon dioxide is 0.51:1, the molar ratio of water to silicon dioxide is 23.71:1, and the amount of seed crystals added is 2.0%.
[0057] Example 7
[0058] Weigh 971.2g of water glass and pour it into a beaker. Then weigh 354.49g of chemical water and add it to the beaker. After stirring evenly, slowly add 251.19g of low-absorption precipitate to the beaker containing water glass through a separatory funnel. Then add 211.07g of aluminum sulfate solution through another separatory funnel. After mixing evenly, record the liquid level in the beaker. Then start heating to 96℃, add chemical water to the marked liquid level, heat again to 96℃, add 35.76g of new seed crystals that have been stirred evenly and weighed, and stir evenly again. Transfer all the material in the beaker to a stainless steel synthesis reactor and seal it. Let it stand and age at 100±2℃ for 48h. After that, remove the synthesis reactor, filter, wash with water, and dry to obtain the finished product.
[0059] Test results: Crystallinity 73.3%, cell size 24.77, SAR 4.59, specific surface area 795 m² 2 / g, pore volume 0.44ml / g, mesoporous specific surface area 50m² 2 / g, mesoporous pore volume 0.070ml / g.
[0060] The above experimental feed ratios are as follows: the molar ratio of silicon dioxide to aluminum oxide is 8.38:1, the molar ratio of sodium oxide to silicon dioxide is 0.51:1, the molar ratio of water to silicon dioxide is 23.71:1, and the amount of seed crystals added is 2.0%.
[0061] In the above embodiments, scanning electron microscope images show that the grain size is about 300 nm, which is significantly smaller than that of ordinary Y-type molecular sieves with 1000 nm grains, and is consistent with the correlation of increased mesopore size.
Claims
1. A seed crystal for the preparation of small-grained Y-type molecular sieves, characterized in that: The raw materials include sodium aluminate, sodium silicate, aluminum sulfate, and small-grain seed crystals. The small-grain seed crystals are prepared by mixing sodium silicate, sodium aluminate, and liquid alkaline solution in the following molar ratios (silicon dioxide:aluminum oxide = 15.5~16.5:1, sodium oxide:silicon dioxide = 0.75~0.79:1, water:silicon dioxide = 13.5~13.9:1). The preparation steps of the seed crystals are as follows: Slowly add a liquid alkali solution with a mass fraction higher than 48% to a sodium silicate solution with a mass fraction of 27% or higher. Set up a cold water bath for the reaction, turn on the stirrer, and when the system temperature is below 25°C, slowly add an 18.5%~27% sodium aluminate solution dropwise through a separatory funnel, controlling the reaction temperature at 23~25°C. Add deionized water according to the calculated amount, and stir until homogeneous. After stopping stirring, let it stand at 27~28°C for at least 2 weeks.
2. The seed crystal for preparing small-grained Y-type molecular sieves according to claim 1, characterized in that: The molar ratio of silicon dioxide to aluminum oxide in the raw materials is 16:1, the molar ratio of sodium oxide to silicon dioxide in the raw materials is 0.78:1, and the molar ratio of water molecules to silicon dioxide in the raw materials is 13.75:
1.
3. A method for preparing a small-crystal Y-type molecular sieve, characterized in that: Includes the following steps: Calculate the required mass of various raw materials according to a certain ratio based on the raw material analysis indicators; Sodium aluminate solution was added dropwise to sodium silicate solution through a separatory funnel, and the dropping rate was controlled to ensure good fluidity of the reaction system. Add aluminum sulfate and some deionized water to the reaction system, stir well and heat to 96°C; Add the seed crystals of claim 1 or 2 to the reaction system and add a calculated amount of deionized water; The reaction system was further heated to 100℃ and statically crystallized at ambient pressure for 40~50h at 100±2℃. When the reaction system is cooled to 50~70℃, solid-liquid separation is performed on a Buchner funnel. At the same time, the filter cake is washed with deionized water at 60~70℃ and dried to obtain the finished product of small-crystal Y-type molecular sieve.
4. The method for preparing a small-grained Y-type molecular sieve according to claim 3, characterized in that: The amount of seed crystals used is 0.5% to 4% of the total mass of the feed.
5. The method for preparing a small-grained Y-type molecular sieve according to claim 3, characterized in that: The filter cake is rinsed with at least one volume of deionized water, and then dried at an temperature not exceeding 250°C.
6. The method for preparing a small-grained Y-type molecular sieve according to claim 3, characterized in that: The raw materials added in the preparation method have the following molar ratios: silicon dioxide to aluminum oxide is 8.35~8.40:1; sodium oxide to silicon dioxide is 0.50~0.52:1; and water to silicon dioxide is 23~24:
1.
7. The method for preparing a small-crystal Y-type molecular sieve according to claim 6, characterized in that: The ratio of raw materials added in the preparation method is 0.51:1, which is the molar ratio of sodium oxide to silicon dioxide.
8. The method for preparing a small-grained Y-type molecular sieve according to claim 6 or 7, characterized in that: The BET specific surface area of the molecular sieve is 789~808 m². 2 / g, the mesoporous specific surface area of the molecular sieve is 39~50m². 2 / g, wherein the crystallinity of the molecular sieve is 55.3%~74.7%, and the silica-alumina ratio of the molecular sieve is 4.20~5.
08.
9. A small-crystal Y-type molecular sieve prepared using the preparation method described in claim 8.