Preparation method of Y-type molecular sieve catalyst with high rare earth doping content and application of Y-type molecular sieve catalyst in efficient catalytic heavy oil cracking
The preparation of high-relax earth doping Y-type molecular sieve catalysts through modified kaolin and multiple wet roasting processes has solved the problems of waste liquid discharge, high energy consumption and difficult rare earth recovery in the prior art, and achieved efficient and environmentally friendly catalysis Performance improvement.
Patent Information
- Application Number
- CN202411581220.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-07
- Publication Date
- 2025-02-14
AI Technical Summary
The existing preparation methods for rare earth modified Y-type molecular sieve catalysts have problems such as large waste liquid emissions, high energy consumption for roasting, difficult rare earth recovery, and Na ion residue affecting catalytic activity, and it is difficult to accurately regulate the doping amount of rare earth to optimize catalytic performance.
The NaY molecular sieve is prepared by using modified kaolin to provide an aluminum source and a partial silicon source. Through the exchange of rare earth ions and the participation of ammonium sulfate solution during multiple wet roasting, the rare earth doping amount is gradually increased, and the high rare earth doping amount Y is prepared. type molecular sieve catalyst.
The preparation process is simplified, the production cycle is shortened, the rare earth doping amount and catalytic performance of the catalyst is significantly improved, energy consumption and waste liquid emissions are reduced, and the rare earth recovery efficiency is improved.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of molecular sieve catalysts, and in particular relates to a preparation method of a high rare earth doping Y-type molecular sieve catalyst and its application in high-efficiency catalytic heavy oil cracking. Background Art
[0002] Rare earth modified Y-type molecular sieve catalysts occupy a core position in the petroleum refining industry, especially in the process of catalytic cracking of heavy oil into gasoline and diesel. At present, about 80% of gasoline and 40% of diesel on the market are derived from this catalytic cracking technology, highlighting the importance of studying the modification of Y-type molecular sieves to optimize the processing efficiency of heavy oil. The sodium ions on the silicon-aluminum framework of NaY molecular sieves prepared by traditional methods are highly exchangeable and can be effectively replaced with a variety of metal ions such as cerium ions and lanthanum ions. In this ion exchange process, cerium or lanthanum ions migrate to the sodalite S2 site unique to Y-type molecular sieves, and then undergo high-temperature calcination treatment to convert them into rare earth modified Y-type molecular sieve catalysts. The introduction of rare earth elements has profoundly changed the physical and chemical properties of molecular sieves, including reducing the surface acid strength, increasing the specific surface area and average pore size. These changes directly promote the significant improvement of catalytic cracking performance. Therefore, developing a method for preparing a rare earth modified Y-type zeolite catalyst that is both efficient and cost-effective and applying it to the field of heavy oil catalytic cracking is not only an innovation of the existing technology, but can also effectively improve the production efficiency and quality of petroleum products, and has extremely significant industrial application potential and economic value.
[0003] At present, the mainstream method for preparing rare earth modified molecular sieve catalysts in the industry is the liquid phase ion exchange method, which is a post-processing strategy, that is, after the synthesis of NaY molecular sieve is completed, the sodium ions on the surface of its skeleton are replaced with a rare earth salt solution containing lanthanum or cerium, and then subjected to high temperature roasting to form a rare earth modified molecular sieve catalyst. However, this method faces significant challenges: in industrial practice, at least three ion exchanges and three roasting cycles are required, resulting in large waste liquid discharge and high energy consumption in the roasting process; at the same time, the waste liquid is rich in rare earths and sodium salts, and the subsequent treatment is cumbersome and the recovery of rare earths is difficult. In addition, the impregnation method is another preparation method. Although the catalyst is prepared by directly allowing the NaY molecular sieve to adsorb rare earth salt solution and then roasting, there is a problem that the rare earth salt impregnation method in one step causes Na ions to remain on the surface of the molecular sieve, thereby affecting the catalytic activity. In view of the environmental pollution problems and efficiency bottlenecks in the above preparation process, it is particularly urgent and important to explore and develop a new, environmentally friendly and efficient rare earth doped molecular sieve catalyst preparation process.
[0004] In the in-depth study of catalytic cracking of heavy oil, the doping amount of rare earth elements in rare earth modified Y-type molecular sieves has a significant effect on their catalytic performance and the yield and quality of gasoline and diesel. Specifically, when the rare earth content is at a low level, the rare earth ions are mainly enriched on the surface of the molecular sieve; with the increase of the doping amount, the activity of the catalyst and the generation rate of gasoline and coke have increased, however, this change is often accompanied by a decrease in the octane number of gasoline. Therefore, precise control of the rare earth doping amount has become the core strategy for optimizing the comprehensive performance of catalytic cracking catalysts. However, how to achieve the preparation of modified molecular sieves with high rare earth doping while ensuring high efficiency and simplicity is still a technical problem that needs to be overcome in the current research and development of rare earth modified Y-type molecular sieve catalysts. Summary of the invention
[0005] In order to solve the above technical problems, the present invention provides a method for preparing a Y-type molecular sieve catalyst with a high rare earth doping amount and its application in high-efficiency catalytic heavy oil cracking.
[0006] To achieve the above object, the present invention provides the following technical solutions:
[0007] The present invention provides a method for preparing a Y-type molecular sieve catalyst with a high rare earth doping amount, comprising the following steps:
[0008] (1) mixing a directing agent with a silicon source, an aluminum source, sodium hydroxide and water, and subjecting the mixture to aging, crystallization, filtering, washing and drying to obtain a NaY molecular sieve; wherein the aluminum source and part of the silicon source are provided by modified kaolin;
[0009] (2) mixing the NaY molecular sieve obtained in step (1) with an ammonium salt and a rare earth solution, and performing a first calcination in a wet state and an air atmosphere to obtain a rare earth-containing NaY molecular sieve;
[0010] (3) The rare earth-containing NaY molecular sieve obtained in step (2) is mixed with an ammonium sulfate solution and a rare earth solution, and a second calcination is performed in a wet state and an air atmosphere to obtain the high rare earth doping amount Y-type molecular sieve catalyst.
[0011] Preferably, in step (1), the preparation method of the modified kaolin comprises: mixing kaolin and an acid solution, stirring the mixture at 40 to 70° C. for 2 to 4 hours, filtering, and then calcining the solid product obtained by filtration at 750 to 850° C. for 1 to 2 hours to obtain the modified kaolin.
[0012] Preferably, in step (1), the crystallization temperature is 100-110° C. and the time is 2-10 h.
[0013] Preferably, in step (1), the Na in the NaY molecular sieve is 2 O、Al 2 O 3 、SiO2 and H 2 The molar ratio of O is 3.0:1:8.8:248.
[0014] Preferably, in step (1), the silicon source also includes water glass.
[0015] Preferably, in step (2), the usage ratio of the NaY molecular sieve, the ammonium salt and the rare earth solution is 100 g: (15-25) g: (10-20) mL; and the concentration of the rare earth solution is 0.1-0.5 g / mL.
[0016] Preferably, in step (3), the dosage ratio of the rare earth-containing NaY molecular sieve, ammonium sulfate solution and rare earth solution is 100 g: (200-300) mL: (15-30) mL; the concentration of the ammonium sulfate solution is 0.05-0.2 g / mL, and the concentration of the rare earth solution is 0.1-0.5 g / mL.
[0017] Preferably, in step (2) and step (3), the temperature of the first calcination and the second calcination are both 550-620° C., the holding time is both 3-8 h, and the heating rate is both 5-10° C. / min.
[0018] The present invention provides a high rare earth doping Y-type molecular sieve catalyst prepared by the preparation method described in the above technical solution, wherein the rare earth doping amount in the high rare earth doping Y-type molecular sieve catalyst is 10-20wt%.
[0019] The present invention also provides the use of the high rare earth doping Y-type molecular sieve catalyst described in the above technical solution in high-efficiency catalytic heavy oil cracking.
[0020] Compared with the prior art, the present invention has the following advantages and technical effects:
[0021] The invention first adopts modified kaolin to provide aluminum source and part of silicon source to prepare NaY molecular sieve. The modified kaolin has high activity, can participate in the crystallization process and finally generate mesoporous NaY molecular sieve, which is helpful for subsequent rare earth doping. Then, the NaY molecular sieve is mixed with ammonium salt and rare earth solution to realize the exchange of rare earth ions. Then, the rare earth ions are calcined in a wet state and air atmosphere to convert rare earth ions into rare earth oxides, thereby obtaining the rare earth-containing NaY molecular sieve. Finally, on the basis of the rare earth-containing NaY molecular sieve, ammonium sulfate solution and rare earth solution are further used for ion exchange, and then calcination is performed to further increase the rare earth doping amount in the Y-type molecular sieve, thereby obtaining a Y-type molecular sieve catalyst with a high rare earth doping amount.
[0022] The preparation method provided by the present invention not only simplifies the preparation process, but also significantly shortens the production cycle of high rare earth doping Y-type molecular sieve catalysts, and has obvious advantages over traditional rare earth modified molecular sieve catalyst preparation methods. DETAILED DESCRIPTION
[0023] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0024] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with specific implementation methods.
[0025] The embodiment of the present invention provides a method for preparing a Y-type molecular sieve catalyst with a high rare earth doping amount, comprising the following steps:
[0026] (1) mixing a directing agent with a silicon source, an aluminum source, sodium hydroxide and water, and subjecting the mixture to aging, crystallization, filtering, washing and drying to obtain a NaY molecular sieve; wherein the aluminum source and part of the silicon source are provided by modified kaolin;
[0027] The present invention adopts modified kaolin to provide aluminum source and part of silicon source to prepare NaY molecular sieve. The modified kaolin has high activity, can participate in the crystallization process and finally generate mesoporous NaY molecular sieve, which is helpful for subsequent rare earth doping.
[0028] (2) mixing the NaY molecular sieve obtained in step (1) with an ammonium salt and a rare earth solution, and performing a first calcination in a wet state and an air atmosphere to obtain a rare earth-containing NaY molecular sieve;
[0029] The invention realizes the exchange of rare earth ions by mixing NaY molecular sieve with ammonium salt and rare earth solution, and then calcines in a wet state and air atmosphere to convert the rare earth ions into rare earth oxides, thereby obtaining the rare earth-containing NaY molecular sieve.
[0030] (3) The rare earth-containing NaY molecular sieve obtained in step (2) is mixed with an ammonium sulfate solution and a rare earth solution, and a second calcination is performed in a wet state and an air atmosphere to obtain the high rare earth doping amount Y-type molecular sieve catalyst.
[0031] The invention further uses ammonium sulfate solution and rare earth solution to carry out ion exchange on the basis of rare earth-containing NaY molecular sieve, and then carries out calcination, thereby further increasing the rare earth doping amount in the Y-type molecular sieve, thereby obtaining a Y-type molecular sieve catalyst with a high rare earth doping amount.
[0032] In a preferred embodiment, in step (1), the preparation method of the directing agent comprises: mixing sodium hydroxide, sodium aluminate, water glass and water according to 3-10 Na 2 O∶1Al 2 O 3 ∶5~10SiO 2 : 150~300H 2 The mixture is mixed at a molar ratio of 1:1 to 2:1 at 20 to 40° C. for 1 to 2 hours, and then aged at 20 to 40° C. for 10 to 12 hours to obtain the directing agent.
[0033] In a preferred embodiment, in step (1), the preparation method of the modified kaolin comprises: mixing kaolin and an acid solution, stirring and treating at 40-70°C for 2-4h, filtering, and then calcining the filtered solid product at 750-850°C for 1-2h to obtain the modified kaolin. The present invention first treats kaolin with an acid solution to remove impurities therein, and then calcines it to activate the kaolin and participate in the crystallization process and finally generate a mesoporous NaY molecular sieve. When the calcination temperature in the present invention is too low or too high, the activity of the modified kaolin obtained is low, and the mesoporous NaY molecular sieve cannot be generated.
[0034] In a preferred embodiment, the acid solution includes hydrochloric acid and / or nitric acid, and the mass concentration of the acid solution is 10-20%; the mass ratio of kaolin to the acid solution is 1:(10-20), and more preferably 1:(15-20).
[0035] In a preferred embodiment, in step (1), the aging temperature is room temperature and the time is 1 to 2 hours.
[0036] In a preferred embodiment, in step (1), the crystallization temperature is 100-110° C., more preferably 100-105° C.; the crystallization time is 2-10 h, more preferably 3-7 h.
[0037] In a preferred embodiment, in step (1), the NaY molecular sieve has Na 2 O、Al 2 O 3 、SiO 2 and H 2 The molar ratio of O is 3.0:1:8.8:248 (the ratio of each raw material can be calculated from this composition).
[0038] In a preferred embodiment, in step (1), the silicon source further comprises water glass.
[0039] In a preferred embodiment, in step (2), the dosage ratio of the NaY molecular sieve, the ammonium salt and the rare earth solution is 100 g: (15-25) g: (10-20) mL, and more preferably 100 g: (18-23) g: (12-18) mL; the concentration of the rare earth solution is 0.1-0.5 g / mL, and more preferably 0.2-0.4 g / mL; the rare earth element in the rare earth solution includes lanthanum and / or cerium, and the rare earth solution includes one or more of lanthanum nitrate, cerium nitrate, lanthanum chloride and cerium chloride; and the ammonium salt includes ammonium chloride.
[0040] In a preferred embodiment, in step (2), the mixing temperature is 70-90° C., and the mixing time is 1-2 h.
[0041] In a preferred embodiment, in step (2), the temperature of the first calcination is 550-620°C, more preferably 580-600°C; the holding time of the first calcination is 3-8h, more preferably 4-7h; the heating rate of the first calcination is 5-10°C / min, more preferably 6-8°C / min.
[0042] In a preferred embodiment, in step (3), the dosage ratio of the rare earth-containing NaY molecular sieve, ammonium sulfate solution and rare earth solution is 100g: (200-300)mL: (15-30)mL, and more preferably 100g: (220-260)mL: (18-26)mL; the concentration of the ammonium sulfate solution is 0.05-0.2g / mL, and more preferably 0.05-0.15g / mL; the concentration of the rare earth solution is 0.1-0.5g / mL, and more preferably 0.2-0.4g / mL; the rare earth element in the rare earth solution includes lanthanum and / or cerium, and the rare earth solution includes one or more of lanthanum nitrate, cerium nitrate, lanthanum chloride and cerium chloride.
[0043] In a preferred embodiment, in step (3), the mixing temperature is 70 to 90° C., and the mixing time is 1 to 2 hours.
[0044] In a preferred embodiment, in step (3), the temperature of the second calcination is 550-620°C, more preferably 580-600°C; the holding time of the second calcination is 3-8h, more preferably 4-7h; the heating rate of the second calcination is 5-10°C / min, more preferably 6-8°C / min.
[0045] The present invention provides a high rare earth doping Y-type molecular sieve catalyst prepared by the preparation method described in the above technical solution, wherein the rare earth doping amount in the high rare earth doping Y-type molecular sieve catalyst is 10-20wt%.
[0046] The present invention also provides the use of the high rare earth doping Y-type molecular sieve catalyst described in the above technical solution in high-efficiency catalytic heavy oil cracking.
[0047] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.
[0048] In the following examples, the composition of kaolin is: SiO 2 56.23%, Al 2 O 3 23.91%, Fe 2 O 3 0.83%, CaO 0.09%, MgO 0.34%, SO 3 0.04%.
[0049] Example 1
[0050] A method for preparing a Y-type molecular sieve catalyst with a high rare earth doping amount, the specific steps are as follows:
[0051] (1) Al 2 O 3 The content is 40.3wt%, Na 2 Sodium aluminate with an O content of 28.7% was dissolved in deionized water, and then sodium hydroxide was added under mechanical stirring to obtain a high-basicity sodium aluminate solution; the high-basicity sodium aluminate solution was added to SiO 2 The content is 24.5wt%, Na 2 O content of 6.8wt% water glass, mixed and stirred at 30 ° C for 2h, and then aged at 30 ° C for 10h to obtain a directing agent, wherein sodium hydroxide, sodium aluminate, water glass and deionized water are mixed according to 5Na 2 O∶1Al 2 O 3 ∶8SiO 2 :265H 2 O was added at a molar ratio.
[0052] (2) 10 g of kaolin and 150 g of nitric acid solution with a mass concentration of 15% were mixed, stirred at 45° C. for 2 h, filtered, and then the solid product obtained by filtration was calcined at 780° C. for 1 h to obtain modified kaolin. The composition of the modified kaolin was: SiO 2 62.18%、Al 2 O 3 25.03%, Fe 2 O 3 0.12%, CaO 0.03%, MgO 0.09%, SO 3 0.01%;
[0053] (3) The directing agent obtained in step (1) and the modified kaolin obtained in step (2) are mixed with water glass, sodium hydroxide and deionized water, aged at room temperature for 2 hours, then crystallized at 105° C. for 3 hours, filtered, and the solid product obtained by filtration is washed with deionized water until neutral, and dried in a vacuum drying oven at 50° C. to finally obtain Na 2 O、Al 2 O 3 、SiO 2 and H 2 NaY molecular sieve with a molar ratio of 3.0:1:8.8:248;
[0054] (4) 100 g of the NaY molecular sieve obtained in step (3), 18 g of ammonium chloride and 15 mL of a 0.4 g / mL lanthanum nitrate solution were mixed and stirred at 70° C. for 1.5 h, and then a first calcination was performed in a wet state and in an air atmosphere. The first calcination temperature was 580° C., the holding time was 4 h, and the heating rate was 8° C. / min to obtain a rare earth-containing NaY molecular sieve;
[0055] (5) 100 g of the rare earth-containing NaY molecular sieve obtained in step (4) was mixed with 260 mL of 0.15 g / mL ammonium sulfate solution and 20 mL of 0.4 g / mL lanthanum nitrate solution at 70° C. and stirred for 1.5 h, and then a second calcination was performed in a wet state and air atmosphere. The second calcination temperature was 580° C., the insulation time was 4 h, and the heating rate was 8° C. / min to obtain a high lanthanum doping amount Y-type molecular sieve catalyst.
[0056] Example 2
[0057] A method for preparing a Y-type molecular sieve catalyst with a high rare earth doping amount, the specific steps are as follows:
[0058] Steps (1) to (3) are the same as in Example 1;
[0059] (4) 100 g of the NaY molecular sieve obtained in step (3), 23 g of ammonium chloride and 12 mL of a 0.3 g / mL lanthanum nitrate solution were mixed and stirred at 75° C. for 1.5 h, and then a first calcination was performed in a wet state and in an air atmosphere. The first calcination temperature was 600° C., the holding time was 5 h, and the heating rate was 8° C. / min to obtain a rare earth-containing NaY molecular sieve;
[0060] (5) 100 g of the rare earth-containing NaY molecular sieve obtained in step (4) was mixed with 300 mL of 0.08 g / mL ammonium sulfate solution and 26 mL of 0.3 g / mL lanthanum nitrate solution at 75° C. and stirred for 1.5 h, and then a second calcination was performed in a wet state and air atmosphere. The second calcination temperature was 600° C., the insulation time was 5 h, and the heating rate was 8° C. / min to obtain a high lanthanum doping amount Y-type molecular sieve catalyst.
[0061] Example 3
[0062] A method for preparing a Y-type molecular sieve catalyst with a high rare earth doping amount, the specific steps are as follows:
[0063] Steps (1) to (3) are the same as in Example 1;
[0064] (4) 100 g of the NaY molecular sieve obtained in step (3), 15 g of ammonium chloride and 20 mL of a 0.5 g / mL cerium nitrate solution were mixed and stirred at 80° C. for 1 h, and then a first calcination was performed in a wet state and in an air atmosphere. The first calcination temperature was 550° C., the holding time was 6 h, and the heating rate was 10° C. / min to obtain a rare earth-containing NaY molecular sieve;
[0065] (5) 100 g of the rare earth-containing NaY molecular sieve obtained in step (4) was mixed with 200 mL of 0.1 g / mL ammonium sulfate solution and 15 mL of 0.5 g / mL cerium nitrate solution at 80° C. and stirred for 1 h, and then a second calcination was performed in a wet state and air atmosphere. The second calcination temperature was 550° C., the insulation time was 6 h, and the heating rate was 10° C. / min to obtain a high cerium-doped Y-type molecular sieve catalyst.
[0066] Example 4
[0067] A method for preparing a Y-type molecular sieve catalyst with a high rare earth doping amount, the specific steps are as follows:
[0068] Steps (1) to (3) are the same as in Example 1;
[0069] (4) 100 g of the NaY molecular sieve obtained in step (3), 20 g of ammonium chloride and 15 mL of a 0.3 g / mL cerium nitrate solution were mixed and stirred at 70° C. for 2 h, and then a first calcination was performed in a wet state and in an air atmosphere. The first calcination temperature was 560° C., the holding time was 7 h, and the heating rate was 6° C. / min to obtain a rare earth-containing NaY molecular sieve;
[0070] (5) 100 g of the rare earth-containing NaY molecular sieve obtained in step (4) was mixed with 280 mL of 0.05 g / mL ammonium sulfate solution and 24 mL of 0.3 g / mL cerium nitrate solution at 70° C. and stirred for 2 h, and then a second calcination was performed in a wet state and air atmosphere. The second calcination temperature was 580° C., the insulation time was 6 h, and the heating rate was 10° C. / min to obtain a high cerium-doped Y-type molecular sieve catalyst.
[0071] Example 5
[0072] A method for preparing a Y-type molecular sieve catalyst with a high rare earth doping amount, the specific steps are as follows:
[0073] (1) Al2 O 3 The content is 40.3wt%, Na 2 Sodium aluminate with an O content of 28.7% was dissolved in deionized water, and then sodium hydroxide was added under mechanical stirring to obtain a high-basicity sodium aluminate solution; the high-basicity sodium aluminate solution was added to SiO 2 The content is 24.5wt%, Na 2 O content of 6.8wt% water glass, mixed and stirred at 25 ° C for 1h, and then aged at 35 ° C for 12h to obtain a directing agent, wherein sodium hydroxide, sodium aluminate, water glass and deionized water are mixed according to 8Na 2 O∶1Al 2 O 3 ∶6SiO 2 : 280H 2 O was added at a molar ratio.
[0074] (2) 10 g of kaolin and 100 g of a 15% hydrochloric acid solution were mixed, stirred at 55° C. for 3 h, filtered, and then the solid product obtained by filtration was calcined at 820° C. for 1 h to obtain modified kaolin. The modified kaolin had the following components: SiO 2 64.27%、Al 2 O 3 24.76%, Fe 2 O 3 0.17%, CaO 0.04%, MgO 0.11%, SO 3 0.01%;
[0075] (3) The directing agent obtained in step (1) and the modified kaolin obtained in step (2) are mixed with water glass, sodium hydroxide and deionized water, aged at room temperature for 1 hour, then crystallized at 110° C. for 5 hours, filtered, and the solid product obtained by filtration is washed with deionized water until neutral, and dried in a vacuum drying oven at 50° C. to finally obtain Na 2 O、Al 2 O 3 、SiO 2 and H 2 NaY molecular sieve with a molar ratio of 3.0:1:8.8:248;
[0076] Steps (4) to (5) are the same as in Example 1.
[0077] Comparative Example 1
[0078] The difference from Example 1 is that step (2) is omitted, that is, unmodified kaolin is used, and the remaining steps are the same as Example 1.
[0079] Comparative Example 2
[0080] The difference from Example 1 is that step (4) is omitted, and the remaining steps are the same as Example 1.
[0081] Comparative Example 3
[0082] The difference from Example 1 is that step (5) is omitted, and the remaining steps are the same as Example 1.
[0083] Comparative Example 4
[0084] The difference from Example 1 is that in step (4), 100 g of the NaY molecular sieve obtained in step (3), 10 g of ammonium chloride and 12 mL of a 0.3 g / mL lanthanum nitrate solution are mixed and stirred at 75° C. for 1.5 h, and then a first calcination is carried out in a wet state and in an air atmosphere. The first calcination temperature is 580° C., the holding time is 4 h, and the heating rate is 8° C. / min to obtain a rare earth-containing NaY molecular sieve; the remaining steps are the same as in Example 1.
[0085] Comparative Example 5
[0086] The difference from Example 1 is that in step (4), 100 g of the NaY molecular sieve obtained in step (3), 30 g of ammonium chloride and 12 mL of a 0.3 g / mL lanthanum nitrate solution are mixed and stirred at 75° C. for 1.5 h, and then a first calcination is carried out in a wet state and in an air atmosphere. The first calcination temperature is 580° C., the holding time is 4 h, and the heating rate is 8° C. / min to obtain a rare earth-containing NaY molecular sieve; the remaining steps are the same as in Example 1.
[0087] Comparative Example 6
[0088] The difference from Example 1 is that in step (5), 100 g of the rare earth-containing NaY molecular sieve obtained in step (4) is mixed with 150 mL of 0.05 g / mL ammonium sulfate solution and 24 mL of 0.3 g / mL cerium nitrate solution at 70° C. and stirred for 2 h, and then a second calcination is carried out in a wet state and air atmosphere, the second calcination temperature is 580° C., the insulation time is 4 h, and the heating rate is 8° C. / min; the remaining steps are the same as in Example 1.
[0089] Comparative Example 7
[0090] The difference from Example 1 is that in step (5), 100 g of the rare earth-containing NaY molecular sieve obtained in step (4) is mixed with 400 mL of 0.05 g / mL ammonium sulfate solution and 24 mL of 0.3 g / mL cerium nitrate solution at 70° C. and stirred for 2 h, and then a second calcination is carried out in a wet state and air atmosphere, the second calcination temperature is 580° C., the insulation time is 4 h, and the heating rate is 8° C. / min; the remaining steps are the same as in Example 1.
[0091] The catalytic performance of the catalysts prepared in the examples and comparative examples was evaluated on an ACE (advanced cracking evaluation, Kayser, R+Multi Mode reactor). Before the evaluation, the catalyst was deactivated at 800°C and 100% steam for 17 hours, and then the catalyst and crude oil were heated at 530°C, a catalyst-oil ratio (mass) of 5, and a space velocity of 8 h. -1 The catalytic cracking reaction was carried out under the conditions of 9 g catalyst loading in the reactor and the feed rate of crude oil was 1.2 g min -1 The feedstock oil is Wu-mixed 3 feedstock oil. The composition and physical properties of Wu-mixed 3 feedstock oil are shown in Table 1. The ACE evaluation results are shown in Table 2.
[0092] Table 1 Composition and physical properties of Wu-mixed three raw oil
[0093]
[0094]
[0095] Table 2ACE evaluation results
[0096] catalyst <![CDATA[Re 2 O 3 Doping amount / wt.%]]> Conversion rate / % Total liquid yield / % Example 1 13.7 81.66 85.84 Example 2 12.1 81.15 85.80 Example 3 17.2 82.76 86.49 Example 4 11.3 80.64 85.78 Example 5 13.2 81.92 85.73 Comparative Example 1 9.4 76.79 79.93 Comparative Example 2 8.2 75.63 78.94 Comparative Example 3 7.5 74.46 78.03 Comparative Example 4 10.7 76.93 80.04 Comparative Example 5 10.9 77.58 80.93 Comparative Example 6 10.5 76.82 79.83 Comparative Example 7 10.8 77.05 80.12
[0097] It can be seen from Table 1 that when the high rare earth doping Y-type molecular sieve catalysts prepared in Examples 1-5 of the present invention are used for catalytic cracking of heavy oil, the conversion rate can reach over 80% and the total liquid yield can reach over 85%.
[0098] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.
Claims
1. A method for preparing a Y-type molecular sieve catalyst with a high rare earth doping content, characterized in that: The following steps are involved: (1) mixing a directing agent with a silicon source, an aluminum source, sodium hydroxide and water, and subjecting the mixture to aging, crystallization, filtering, washing and drying to obtain a NaY molecular sieve; wherein the aluminum source and part of the silicon source are provided by modified kaolin; (2) mixing the NaY molecular sieve obtained in step (1) with an ammonium salt and a rare earth solution, and performing a first calcination in a wet state and an air atmosphere to obtain a rare earth-containing NaY molecular sieve; (3) The rare earth-containing NaY molecular sieve obtained in step (2) is mixed with an ammonium sulfate solution and a rare earth solution, and a second calcination is performed in a wet state and an air atmosphere to obtain the high rare earth doping amount Y-type molecular sieve catalyst.
2. The preparation method according to claim 1, characterized in that: In step (1), the preparation method of the modified kaolin comprises: mixing kaolin and an acid solution, stirring the mixture at 40 to 70° C. for 2 to 4 hours, filtering the mixture, and then calcining the solid product obtained by filtration at 750 to 850° C. for 1 to 2 hours to obtain the modified kaolin.
3. The preparation method according to claim 1, characterized in that: In step (1), the crystallization temperature is 100-110° C. and the crystallization time is 2-10 hours.
4. The preparation method according to claim 1, characterized in that: In step (1), the molar ratio of Na2O, Al2O3, SiO2 and H2O in the NaY molecular sieve is 3.0:1:8.8:
248.
5. The preparation method according to claim 1, characterized in that: In step (1), the silicon source also includes water glass.
6. The preparation method according to claim 1, characterized in that: In step (2), the dosage ratio of the NaY molecular sieve, the ammonium salt and the rare earth solution is 100 g: (15-25) g: (10-20) mL; and the concentration of the rare earth solution is 0.1-0.5 g / mL.
7. The preparation method according to claim 1, characterized in that: In step (3), the dosage ratio of the rare earth-containing NaY molecular sieve, ammonium sulfate solution and rare earth solution is 100 g: (200-300) mL: (15-30) mL; the concentration of the ammonium sulfate solution is 0.05-0.2 g / mL, and the concentration of the rare earth solution is 0.1-0.5 g / mL.
8. The preparation method according to claim 1, characterized in that: In step (2) and step (3), the temperature of the first calcination and the second calcination are both 550-620°C, the insulation time is both 3-8h, and the heating rate is both 5-10°C / min.
9. A Y-type molecular sieve catalyst with a high rare earth doping content prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The rare earth doping amount in the high rare earth doping amount Y-type molecular sieve catalyst is 10-20wt%.
10. Use of the high rare earth doping Y-type molecular sieve catalyst according to claim 9 in high-efficiency catalytic heavy oil cracking.