High-yield propylene catalytic cracking catalyst as well as preparation method and application thereof

Abstract

The invention provides a high-yield propylene catalytic cracking catalyst and a preparation method and application thereof.The preparation method comprises the steps that ammonium sulfate is adopted as an exchanger, a precipitator is added after rare earth ion exchange and before ammonium sulfate exchange, the precipitator and rare earth ions preferentially generate a precipitation precursor of rare earth oxide, and then the precipitation precursor of the rare earth oxide is obtained; therefore, the rare earth modified Y-type molecular sieve with low sulfate radical content, high crystallinity and good stability is prepared. Fully and uniformly mixing water, the rare earth modified Y-type molecular sieve, the ZSM-5 molecular sieve, clay and a binder, and then carrying out homogenizing, spray drying and third roasting to prepare a Na-containing catalyst; the preparation method comprises the following steps: mixing and pulping water and Na-containing catalyst particles, adding a phosphorus-containing substance to carry out sodium reduction modification on a Na-containing catalyst, filtering, washing with water, and drying to obtain a finished product of the catalyst. The finished product catalyst uses the rare earth modified Y-type molecular sieve with the characteristics as an active component, so that the finished product catalyst has the advantages of high propylene yield, strong heavy oil conversion capability, high liquid yield and the like.

Description

Technical Field

[0001] The invention relates to a catalytic cracking catalyst for producing more propylene and a preparation method and application thereof, belonging to the technical field of refining. Background Art

[0002] The catalytic cracking unit is still one of the most important units in the refining process. About 70% of gasoline and 35% of propylene come from the catalytic cracking unit. However, with the overcapacity of fuel oil, the relative shortage of chemical raw materials and the accelerated pace of gasoline quality upgrade, new and severe challenges have been posed to catalytic cracking. At the same time, the demand for low-carbon olefins such as chemical raw materials propylene is strong, and the gap between the market demand for propylene and the production capacity of propylene from traditional sources is getting bigger and bigger, and is expanding.

[0003] In summary, how to improve the propylene yield on the basis of efficient conversion of heavy oil is a new task and challenge given to catalytic cracking by the current transformation and upgrading of refining and petrochemicals, and has also become an important research topic for petroleum refiners. The key material for catalytic cracking to produce more propylene is ZSM-5 molecular sieve, but the pore size of ZSM-5 molecular sieve is small, and due to diffusion restrictions, heavy oil macromolecules cannot enter its pores for cracking. It only has strong cracking activity for small molecules in gasoline fractions to increase propylene production. Catalytic cracking reaction is a typical gas-solid heterogeneous reaction, which is a parallel sequential reaction and its reaction is limited by diffusion. Therefore, to increase the production of propylene, on the one hand, heavy oil macromolecules must be converted into gasoline middle fraction molecules through large-pore Y-type molecular sieves, and on the other hand, gasoline molecules must be continued to be cracked and converted into propylene through medium-pore ZSM-5 molecular sieves.

[0004] In this regard, some existing technologies mainly use P to modify ZSM-5 to improve its hydrothermal stability and activity stability, so as to achieve the purpose of increasing the propylene yield; some existing technologies use a combination of USY and ZSM-5 to achieve relay cracking to increase propylene production; some existing technologies produce more propylene through a combination of Y zeolite, ZSM-5 zeolite and β zeolite; some existing technologies increase propylene production by adding medium- and macroporous matrix materials, ZSM-5 protective coatings, etc.

[0005] Although the existing technologies shown above can improve the propylene yield, and more and more attention is paid to the gradient cracking of materials with different pore sizes, the existing Y-type molecular sieves mostly use USY molecular sieves, which have insufficient cracking activity and cannot provide more gasoline intermediate fraction molecules for ZSM-5 cracking to produce more propylene. Therefore, technological innovation is needed to improve the cracking activity and stability of Y-type molecular sieves. Y-type molecular sieves are still the main active components of FCC catalysts due to their unique three-dimensional pore structure, suitable acidity and good stability. Their performance determines the activity, stability, heavy oil conversion performance and product selectivity of the catalyst, and has also become one of the research hotspots for improving the performance of heavy oil catalysts. The catalytic cracking reaction is a typical acid-catalyzed gas-solid heterogeneous reaction that follows the positive carbon ion mechanism. The NaY molecular sieve itself is not acidic and usually needs to be exchanged and modified to remove its Na ions and adjust its acidity and pore structure. Due to the acid H + Too strong acidity can easily destroy the Y-type molecular sieve framework structure, resulting in a decrease in crystallinity and selectivity. Due to its strong acidity and acid density, REY molecular sieves are prone to coking and deactivation during the catalytic cracking reaction. Therefore, the commonly used modification method is to use ammonium salts and / or rare earths for exchange, and prepare modified REHY or REUSY molecular sieves with different acidity and pore structures through thermal or hydrothermal calcination. At present, the preparation methods of REHY or REUSY molecular sieves can be roughly divided into two categories: one is to first exchange a small amount of rare earth ions and / or ammonium ions with NaY molecular sieves, and then perform rare earth ions and / or ammonium ions or dealuminization after calcination to prepare REUSY molecular sieves; the other is to first make NaY molecular sieves into USY molecular sieves, and then exchange rare earths to prepare REUSY.

[0006] Ammonium chloride is easy to decompose at high temperature and crystallize at low temperature, so it is easy to clog the catalyst flue and bag filter, resulting in the inability to produce continuously. Ammonium nitrate will explode under high temperature, high pressure, oxidizable substances (reducing agents) and electric sparks, and it is a key raw material for making explosives and is expensive, so it is not used. Ammonium sulfate is stable and cheap, and is often used in industrial molecular sieve exchange modification. However, because it easily reacts with rare earths to form rare earth sulfate precipitation, on the one hand, rare earth ions cannot migrate into the cage of the molecular sieve, effectively stabilizing the molecular sieve framework structure. On the other hand, it is easy to cause sulfate to exceed the standard and destroy the molecular sieve framework structure. In addition, after being made into a catalyst, sulfate will be converted into sulfide during the refining process, corroding equipment.

[0007] In the prior art, the method of precipitating rare earths is often used to improve the utilization rate of rare earths, and at the same time, generate independent phase rare earths to improve the V pollution resistance of molecular sieves; rare earths and ammonium salts are exchanged simultaneously, and the exchange efficiency is low due to the competitive exchange; ammonium salt exchange is carried out before rare earth exchange, and the use of ammonium chloride and ammonium nitrate will cause problems such as high cost and equipment corrosion, while the use of low-cost recyclable ammonium sulfate, in order to avoid the formation of sulfate precipitation, requires a large amount of water washing to remove sulfate, which will increase water consumption. Although pre-exchange can reduce the sodium oxide and sulfate of the modified molecular sieve, it has the problems of long process, water consumption and high cost. REY molecular sieves prepared without ammonium salts have the problem of high coke generation.

[0008] In short, the existing technology inevitably brings problems such as high sulfate, low crystallinity, equipment corrosion, long production process and high cost. Therefore, it is urgent to develop a new method for preparing low-sulfate rare earth ion molecular sieves to improve the activity, stability and heavy oil conversion capacity of catalytic cracking catalysts, and avoid the conversion of sulfate into sulfide during application, which will corrode the equipment. Summary of the invention

[0009] In order to solve the above-mentioned shortcomings and deficiencies, an object of the present invention is to provide a catalytic cracking catalyst for increasing the yield of propylene.

[0010] Another object of the present invention is to provide a method for preparing the above-mentioned propylene-producing catalytic cracking catalyst.

[0011] Another object of the present invention is to provide the use of the above-mentioned propylene-producing catalytic cracking catalyst in the production of propylene by catalytic cracking of heavy oil.

[0012] In order to achieve the above objectives, on the one hand, the present invention provides a method for preparing a propylene catalytic cracking catalyst, wherein the preparation method comprises:

[0013] (1) Preparation of low sulfate rare earth modified Y-type molecular sieve:

[0014] Step 1: exchanging rare earth ions with Na-type molecular sieve to obtain rare earth ion slurry / rare earth ion exchange slurry;

[0015] Step 2: adding a first precipitant to cause the rare earth ions in the rare earth ion exchange slurry to undergo a first precipitation to obtain a first precipitation slurry;

[0016] Step 3: the first precipitation slurry is filtered, subjected to a first ammonium sulfate exchange, subjected to a first water wash, and subjected to a first roasting in sequence to obtain a cross-exchanged and roasted molecular sieve dry powder;

[0017] Step 4: slurrying the cross-linked and roasted molecular sieve powder with water, adding a second precipitant to allow the rare earth ions in the cross-linked and roasted molecular sieve powder to undergo a second precipitation, and then sequentially performing a second ammonium sulfate exchange, a second water washing, and a second roasting to obtain a low sulfate rare earth modified Y-type molecular sieve;

[0018] (2) Catalyst molding:

[0019] The Na-containing catalyst is prepared by fully mixing water, a low-sulfate rare earth modified Y-type molecular sieve, a ZSM-5 molecular sieve, clay and a binder, and then homogenizing, spray drying and third calcining.

[0020] (3) Modification of phosphorus-containing substances to reduce sodium:

[0021] The water and the Na-containing catalyst particles are mixed and slurried, and then phosphorus-containing substances are added to modify the Na-containing catalyst by reducing sodium, and then the catalyst is filtered, washed with water and dried to obtain a catalyst for catalytic cracking of high-yield propylene.

[0022] As a specific embodiment of the preparation method described above of the present invention, in step 1, the conditions for rare earth ion exchange include: temperature of 25-180°C, preferably 50-80°C; pH of 2.8-6.5, preferably 3.5-4.5; time of 0.3-3.5h, preferably 0.5-1.5h.

[0023] As a specific embodiment of the preparation method described above in the present invention, the rare earth ion exchange process includes: mixing the Na-type molecular sieve and water, and then adding a soluble rare earth salt to perform the rare earth ion exchange.

[0024] As a specific embodiment of the preparation method described above in the present invention, the weight ratio of the Na-type molecular sieve to water is 1:1.5-30, for example, 1:1.5, 1:2, 1:3, 1:4, 1:5, 1:10, 1:20, 1:30, and any value in the range of any two numerical values, preferably 1:2-5.

[0025] As a specific embodiment of the preparation method described above, the content of the soluble rare earth salt in terms of oxide in the Na-type molecular sieve in terms of dry basis is 1-20wt%, for example, 1wt%, 4wt%, 6wt%, 8wt%, 10wt%, 12wt%, 14wt%, 16wt%, 20wt%, and any value in the range of any two values, preferably 6-16wt%. The preferred conditions are more conducive to reducing the sulfate content in the low-sulfate rare earth modified Y-type molecular sieve, thereby eliminating the influence of sulfate on the performance of the low-sulfate rare earth modified Y-type molecular sieve, and improving the crystallinity and catalytic performance of the low-sulfate rare earth modified Y-type molecular sieve.

[0026] In the present invention, during the rare earth ion exchange process, the rare earth ions in the soluble rare earth salt are completely attached to the surface and internal pores of the Na-type molecular sieve. Therefore, the weight ratio of the Na-type molecular sieve calculated on a dry basis to the soluble rare earth salt calculated on an oxide basis is 100:1-20, preferably 100:6-16.

[0027] In the present invention, unless otherwise specified, solubility means being easily soluble in water or being easily soluble in water with the help of an auxiliary agent.

[0028] As a specific embodiment of the preparation method described above, the soluble rare earth salt is selected from one or a combination of soluble nitrates, chlorides, etc. of rare earth metals such as lanthanum, cerium, and yttrium.

[0029] As a specific embodiment of the above preparation method of the present invention, wherein the silicon-aluminum ratio of the Na-type molecular sieve is 2-100, preferably 2-50.

[0030] As a specific embodiment of the preparation method described above of the present invention, the Na-type molecular sieve is selected from at least one of NaY molecular sieve, NaHY molecular sieve, NaUSY molecular sieve, NaREHY molecular sieve, NaREUSY molecular sieve, Naβ molecular sieve, NaHβ molecular sieve, NaREHβ molecular sieve, NaX molecular sieve, NaREX molecular sieve and NaHX molecular sieve, preferably selected from NaY molecular sieve and / or NaHY molecular sieve.

[0031] As a specific embodiment of the preparation method described above of the present invention, in step 2, the amount of the first precipitant is determined according to the amount of rare earth ions added, and the molar ratio in the precipitation reaction can be satisfied. For example, the amount of the first precipitant satisfies the molar ratio of the rare earth ions with a content of 1-4wt% in the Na-type molecular sieve through the first precipitation, and preferably satisfies the molar ratio of the rare earth ions with a content of 1.5-2.5wt% in the Na-type molecular sieve through the first precipitation. The preferred conditions are more conducive to reducing the sulfate content of the low-sulfate rare earth modified Y-type molecular sieve, thereby improving the crystallinity and catalytic performance of the low-sulfate rare earth modified Y-type molecular sieve.

[0032] As a specific embodiment of the preparation method described above of the present invention, the first precipitant is a precipitant that can cause the rare earth element to form an oxide precipitate, for example, it can be selected from at least one of ammonium oxalate, ammonium carbonate, ammonium bicarbonate, ammonia water, urea and ammonium acetate, and is preferably selected from at least one of ammonium oxalate, ammonium carbonate, ammonium bicarbonate and ammonia water.

[0033] As a specific embodiment of the preparation method described above of the present invention, the conditions of the first precipitation include: temperature of 25-180°C, preferably 50-80°C; time of 0.1-5h, preferably 0.1-2h.

[0034] As a specific embodiment of the preparation method described above in the present invention, in step three, the process of exchanging the first ammonium sulfate comprises: exchanging the filtered product with the first ammonium sulfate aqueous solution.

[0035] As a specific embodiment of the preparation method described above of the present invention, the weight ratio of the first ammonium sulfate aqueous solution and the Na-type molecular sieve calculated as ammonium sulfate is 5-50:100, for example, 5:100, 10:100, 15:100, 20:100, 25:100, 30:100, 40:100, 50:100, and any value in the range composed of any two values, preferably 10-25:100.

[0036] As a specific embodiment of the preparation method described above of the present invention, the concentration of ammonium sulfate in the first aqueous ammonium sulfate solution is 20-400 g / L, for example, 20 g / L, 50 g / L, 80 g / L, 120 g / L, 150 g / L, 200 g / L, 250 g / L, 300 g / L, 400 g / L, and any value in the range consisting of any two values, preferably 120-250 g / L.

[0037] As a specific embodiment of the preparation method described above of the present invention, the conditions for the first ammonium sulfate exchange include: temperature of 15-150° C., preferably 50-80° C.; time of 0.1-5 h, preferably 0.5-2 h.

[0038] As a specific embodiment of the preparation method described above in the present invention, wherein the first ammonium sulfate exchange is performed by tank exchange (tank exchange), belt exchange (belt exchange) or tank exchange and belt exchange are performed simultaneously; preferably, tank exchange is performed.

[0039] As a specific embodiment of the preparation method described above in the present invention, in step three, the amount of water used in the first water washing is 1-8 times the weight of the Na-type molecular sieve, for example, 1 times, 2 times, 3 times, 4 times, 5 times, 8 times, and any value in the range of any two values, preferably 2-5 times.

[0040] As a specific embodiment of the preparation method described above, the conditions of the first calcination include: 100% water vapor atmosphere; temperature of 400-700°C, preferably 500-650°C; time of 0.1-5h, preferably 0.5-3h.

[0041] As a specific embodiment of the preparation method described above of the present invention, in step 4, the amount of the second precipitant is determined according to the amount of rare earth ions added, and the molar ratio in the precipitation reaction can be satisfied. For example, the amount of the second precipitant satisfies the molar ratio of the rare earth ions in the cross-baked molecular sieve dry powder with a content of 0.5-3wt% through the second precipitation, and preferably satisfies the molar ratio of the rare earth ions in the cross-baked molecular sieve dry powder with a content of 1-2wt% through the second precipitation. The preferred conditions are more conducive to reducing the sulfate content of the low sulfate rare earth modified Y-type molecular sieve, thereby improving the crystallinity and catalytic performance of the low sulfate rare earth modified Y-type molecular sieve.

[0042] As a specific embodiment of the preparation method described above of the present invention, the second precipitant is a precipitant that can cause the rare earth element to form an oxide precipitate, for example, it can be selected from at least one of ammonium oxalate, ammonium carbonate, ammonium bicarbonate, ammonia water, urea and ammonium acetate, and is preferably selected from at least one of ammonium oxalate, ammonium carbonate, ammonium bicarbonate and ammonia water.

[0043] As a specific embodiment of the preparation method described above of the present invention, the conditions of the second precipitation include: temperature of 15-40°C, preferably 20-30°C; time of 0.1-5h, preferably 0.1-2h.

[0044] As a specific embodiment of the preparation method described above of the present invention, the weight ratio of the cross-baked molecular sieve dry powder to water is 1:1.5-30, for example, 1:1.5, 1:2, 1:3, 1:4, 1:5, 1:10, 1:20, 1:30, and any value in the range composed of any two values, preferably 1:2-5.

[0045] As a specific embodiment of the preparation method described above in the present invention, in step 4, the process of exchanging the second ammonium sulfate comprises: exchanging the second precipitated product with the second ammonium sulfate aqueous solution.

[0046] As a specific embodiment of the preparation method described above of the present invention, the weight ratio of the second aqueous ammonium sulfate solution to the cross-calcined molecular sieve dry powder, calculated as ammonium sulfate, is 5-50:100, for example, 5:100, 10:100, 15:100, 20:100, 25:100, 30:100, 40:100, 50:100, and any value in the range composed of any two values, preferably 10-25:100.

[0047] As a specific embodiment of the preparation method described above of the present invention, the concentration of ammonium sulfate in the second aqueous ammonium sulfate solution is 20-400 g / L, for example, 20 g / L, 50 g / L, 80 g / L, 120 g / L, 150 g / L, 200 g / L, 250 g / L, 300 g / L, 400 g / L, preferably 120-250 g / L.

[0048] As a specific embodiment of the above preparation method of the present invention, the conditions for the second ammonium sulfate exchange include: temperature of 20-85°C, preferably 50-80°C; time of 0.1-5h, preferably 0.1-2h.

[0049] As a specific embodiment of the preparation method described above in the present invention, wherein the second ammonium sulfate exchange is carried out by tank delivery, belt delivery, or tank delivery and belt delivery at the same time; preferably, tank delivery.

[0050] As a specific embodiment of the preparation method described above of the present invention, the amount of water used in the second water washing is 1-8 times the weight of the cross-baked molecular sieve dry powder, for example, 1 time, 2 times, 3 times, 4 times, 5 times, 8 times, and any value in the range of any two values, preferably 2-5 times.

[0051] As a specific embodiment of the preparation method described above, the conditions of the second calcination include: 100% water vapor atmosphere; temperature of 400-700°C, preferably 550-680°C; time of 0.1-10h, preferably 0.5-5h.

[0052] As a specific embodiment of the preparation method described above, in the low sulfate rare earth modified Y-type molecular sieve, SO4 2- The content is ≤1.0wt%, more preferably ≤0.5wt%, and further preferably 0.01-0.45wt%.

[0053] As a specific embodiment of the preparation method described above, the step (2) of catalyst shaping comprises:

[0054] Based on 100 parts of the dry basis weight of the Na-containing catalyst, water, 28-42 parts of a low-sulfate rare earth modified Y-type molecular sieve, 2-15 parts of a ZSM-5 molecular sieve, 30-65 parts of clay, and 6.5-30 parts of a binder are fully mixed to prepare a slurry with a solid content of 25-50wt%, and then homogenized, spray-formed, and thirdly calcined to obtain a Na-containing catalyst.

[0055] Preferably, based on 100 parts of the dry basis mass of the catalyst, water, 28-38 parts of low sulfate rare earth modified Y-type molecular sieve, 3-8 parts of ZSM-5 molecular sieve, 35-50 parts of clay, and 7-27 parts of a binder are fully mixed to form a slurry with a solid content of 35-45wt%, which is then homogenized, spray-formed, and calcined for the third time to obtain a Na-containing catalyst.

[0056] As a specific embodiment of the preparation method described above in the present invention, the ZSM-5 molecular sieve includes at least one of HZSM-5, phosphorus-modified ZSM-5, etc.

[0057] As a specific embodiment of the preparation method described above of the present invention, the clay includes at least one of kaolin, halloysite, porphyrite, diatomite, vesicle and the like.

[0058] As a specific embodiment of the preparation method described above in the present invention, the binder includes at least one of aluminum sol, acidified pseudo-boehmite, acidic silica sol, phosphate aluminum sol, etc.

[0059] As a specific embodiment of the preparation method described above of the present invention, the conditions of the third calcination include: air atmosphere; temperature of 420-480° C.; and time of 20-50 min.

[0060] As a specific embodiment of the preparation method described above of the present invention, in step (3), based on the total dry weight of the Na-containing catalyst as 100%, 1-3wt% of phosphorus-containing substance calculated as P2O5 is added to modify the Na-containing catalyst to reduce sodium.

[0061] Preferably, based on 100% of the total dry weight of the Na-containing catalyst, 1.3-2.5 wt% of phosphorus-containing material calculated as P2O5 is added to modify the Na-containing catalyst to reduce sodium.

[0062] As a specific embodiment of the preparation method described above in the present invention, the weight ratio of water to Na-containing catalyst particles is 0.5-35:1.

[0063] As a specific embodiment of the preparation method described above of the present invention, the water washing temperature is 20-100° C. and the washing time is 0.1-0.3 h.

[0064] As a specific embodiment of the preparation method described above in the present invention, the phosphorus-containing substance includes at least one of phosphoric acid, ammonium phosphate, diammonium hydrogen phosphate, and ammonium dihydrogen phosphate.

[0065] On the other hand, the present invention further provides a catalytic cracking catalyst for increasing propylene yield, wherein the catalytic cracking catalyst for increasing propylene yield is prepared by the preparation method of the catalytic cracking catalyst for increasing propylene yield described above.

[0066] As a specific embodiment of the above-mentioned high-yield propylene catalytic cracking catalyst of the present invention, based on the total weight of the high-yield propylene catalytic cracking catalyst as 100%, it contains 28-42wt% of low sulfate rare earth modified Y-type molecular sieve, 2-15wt% of ZSM-5 molecular sieve, 6.5-30wt% of binder, 30-65wt% of clay and 1-3wt% of phosphorus-containing compounds calculated as P2O5.

[0067] In another aspect, the present invention also provides the use of the above-mentioned high-yield propylene catalytic cracking catalyst in the production of propylene by catalytic cracking of heavy oil.

[0068] Compared with the prior art, the beneficial technical effects that can be achieved by the present invention include:

[0069] The high-yield propylene catalytic cracking catalyst provided by the present invention contains a low-sulfate rare earth modified Y-type molecular sieve. When preparing the low-sulfate rare earth modified Y-type molecular sieve, industrially cheap, harmless and easily recyclable ammonium sulfate is used as an exchange agent, and after rare earth ion exchange and before ammonium sulfate exchange, precipitants such as ammonium oxalate, ammonium carbonate, and ammonia water are added. The added precipitants preferentially react with rare earth ions to form a precipitate precursor of rare earth oxides, thereby avoiding the formation of precipitation by free RE ions and sulfate in the exchange system solution, on the surface of the molecular sieve or in the super cage in the subsequent ammonium sulfate exchange and sodium reduction process, thereby achieving the purpose of reducing the sulfate content, improving the crystallinity and stability of the molecular sieve, and also improving the utilization rate of the rare earth.

[0070] Since the Y-type molecular sieve is the main active component of the catalytic cracking catalyst, its performance determines the performance of the catalytic cracking catalyst. The present invention reduces the sulfate content of the Y-type molecular sieve through the above-mentioned preparation method, improves its crystallinity and stability, so when the low-sulfate rare earth modified Y-type molecular sieve is used as the active component of the catalytic cracking catalyst, it can provide more acidic centers, and correspondingly improve the cracking activity and hydrothermal stability of the catalyst, so that under the catalytic cracking conditions, heavy oil macromolecules can be converted into a large number of gasoline middle distillate molecules, providing more cracking raw materials for ZSM-5, and significantly improving the propylene yield.

[0071] In summary, the low sulfate rare earth modified Y-type molecular sieve prepared by the present invention has the advantages of low sulfate content, high crystallinity, good stability, etc., and using it as an active component of a catalytic cracking catalyst can make the high-yield propylene catalytic cracking catalyst have the characteristics of high propylene yield, strong heavy oil conversion ability, high liquid yield, etc. DETAILED DESCRIPTION

[0072] It should be noted that the term "comprises" and any variations thereof in the specification and claims of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products or devices.

[0073] "Scope" disclosed in the present invention is given in the form of lower limit and upper limit. It can be one or more lower limits, and one or more upper limits respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower limit and upper limit define the boundaries of a particular range. All ranges defined in this way are combinable, i.e. any lower limit can be combined with any upper limit to form a range. For example, for a specific parameter, a range of 60-120 and 80-110 is listed, and it is understood that a range of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​listed are 1 and 2, and the maximum range values ​​listed are 3, 4 and 5, then the following ranges can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5.

[0074] In the present invention, unless otherwise specified, the numerical range "ab" represents an abbreviation of any real number combination between a and b, where a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed in the present invention, and "0-5" is just an abbreviation of these numerical combinations.

[0075] In the present invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in the present invention can be combined with each other to form a new technical solution.

[0076] In the present invention, unless otherwise specified, all technical features and preferred features mentioned in the present invention can be combined with each other to form a new technical solution.

[0077] In the present invention, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0078] In the present invention, unless otherwise specified, "first", "second" and "third" do not indicate a sequence or limit the materials or steps, but are only used to distinguish that they are not the same steps or materials. For example, "first" and "second" in "first ammonium sulfate exchange" and "second ammonium sulfate exchange" are only used to indicate that they are not the same ammonium sulfate exchange.

[0079] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the attached table and examples. The following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to the normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0080] (I) The analysis and evaluation methods used in the examples are as follows:

[0081] 1. Unit cell constant (a0): X-ray diffraction method.

[0082] 2. Crystallinity (C / C0): X-ray diffraction method.

[0083] 3. Silicon to aluminum ratio: X-ray diffraction method.

[0084] 4.Na2O content: XRF fluorescence method.

[0085] 5.RE2O3 content: XRF fluorescence method.

[0086] 6.P2O5 content: XRF fluorescence method.

[0087] 7.Sulfate content: XRF fluorescence method.

[0088] 8. Micro-reaction activity: The samples were pre-treated at 800℃ and 100% steam for different time periods. The reaction raw material was Dagang light diesel oil, the reaction temperature was 460℃, the reaction time was 70 seconds, the catalyst loading was 5.0 grams, the catalyst-oil weight ratio was 3.2, and the total conversion rate was taken as the micro-reaction activity.

[0089] 9.ACE heavy oil microreactor: reaction temperature is 530℃, catalyst-oil ratio is 5, and the raw oil is the raw oil of Lanzhou Petrochemical's 3 million heavy oil catalytic unit.

[0090] (II) The specifications of the raw materials used in the examples are as follows:

[0091] 1. NaY molecular sieve: NaY (silicon-aluminum ratio 5.1, crystallinity 95%), produced by Changting Catalyst Co., Ltd.

[0092] 2. Rare earth precursors: rare earth chloride and rare earth nitrate are both industrial products, collected from the catalyst plant of Lanzhou Petrochemical Company.

[0093] 3.Ammonium sulfate, ammonium oxalate, ammonium carbonate, ammonium bicarbonate, ammonia water, urea, ammonium acetate, ammonium chloride, ammonium nitrate, ammonium phosphate, diammonium hydrogen phosphate, and ammonium dihydrogen phosphate are all of analytical grade.

[0094] 4. Pseudo-boehmite (burn reduction 36.7%), kaolin (burn reduction 18.4%), halloysite (burn reduction 23.2%), porous stone (burn reduction 18.2%), diatomite (burn reduction 23.6%), vesicle stone (burn reduction 25.3%), macroporous alumina (burn reduction 16.8%), boehmite (burn reduction 14.5%), P-modified ZSM-5 (burn reduction 5.6%), macroporous silica-alumina material (solid content 15.4%, pore volume 1.15 mL / g) solids; aluminum sol, containing 22.6wt% of aluminum oxide; silica sol, containing 30.5wt% of silicon oxide, are all industrial qualified products.

[0095] Preparation Example 1

[0096] This preparation example provides a low sulfate rare earth modified Y-type molecular sieve, which is prepared by a preparation method comprising the following specific steps:

[0097] a. After slurrying 1000 g (dry basis weight) of NaY molecular sieve with 5 L of deionized water, add 0.537 L (calculated as La2O3) of 298 g / L LaCl3 solution (La 3+ 0.98 mol) was subjected to rare earth ion exchange (temperature of 80° C., pH of 3.6, time of 0.5 h) to obtain a rare earth ion exchange slurry; wherein the content of LaCl3 calculated as La2O3 in the NaY molecular sieve calculated on a dry basis was 16 wt%;

[0098] b. Adding (32 g, 0.225 mol) ammonium oxalate monohydrate can make 2.4 wt% of La in the above rare earth ion exchange slurry 3+ Performing a first precipitation (temperature of 80° C., time of 0.5 h) to obtain a first precipitation slurry;

[0099] c. Filter the first precipitate slurry, drain it, add 0.833L of 180g / L ammonium sulfate aqueous solution, exchange at 60°C for 1h, drain it, add 3L of water for elution, and then roast it at 550°C in a 100% water vapor atmosphere for 2h to obtain a cross-baked molecular sieve dry powder;

[0100] d. After slurrying the above 1000 g (dry basis) cross-linked and roasted molecular sieve powder with 5 L of deionized water, (25.6 g, 0.18 mol) of ammonium oxalate monohydrate was added to make 2 wt% of La in the above cross-linked and roasted molecular sieve powder. 3+ After the second precipitation (temperature is 25°C, time is 0.5h), add 0.6L of 250g / L ammonium sulfate aqueous solution, exchange at 80°C for 1.5h, filter, drain, add 5L of water for rinsing, and calcine at 650°C in a 100% water vapor atmosphere for 2h to obtain a low sulfate rare earth modified Y-type molecular sieve, recorded as Z1.

[0101] Preparation Example 2

[0102] This preparation example provides a low sulfate rare earth modified Y-type molecular sieve, which is prepared by a preparation method comprising the following specific steps:

[0103] a. After slurrying 1000 g (dry basis weight) of NaY molecular sieve with 5 L of deionized water, add 0.358 L of La(NO3)3 solution (La2O3) with a concentration of 280 g / L 3+ 0.615 mol) was subjected to rare earth ion exchange (temperature of 50° C., pH of 4.0, time of 1.5 h) to obtain a rare earth ion exchange slurry; wherein the content of La(NO3)3 calculated as La2O3 in the NaY molecular sieve calculated on a dry basis was 10 wt%;

[0104] b. Adding (25.6 g, 0.18 mol) ammonium oxalate monohydrate can make 2 wt% of La in the above rare earth ion exchange slurry 3+ Performing a first precipitation (temperature of 50° C., time of 0.5 h) to obtain a first precipitation slurry;

[0105] c. Filter the first precipitate slurry, drain it, add 1.111L of 180g / L ammonium sulfate aqueous solution, exchange at 80°C for 1h, drain it, add 3L of water for elution, and then roast it at 600°C in a 100% water vapor atmosphere for 2h to obtain a cross-baked molecular sieve dry powder;

[0106] d. After slurrying the above 1000 g (dry basis) cross-roasted molecular sieve powder with 5 L of deionized water, add (13 g, 0.135 mol) of ammonium carbonate to make 1.5 wt% of La in the above cross-roasted molecular sieve powder. 3+ After the second precipitation (temperature is 25°C, time is 0.5h), add 1.666L of 120g / L ammonium sulfate aqueous solution, exchange at 50°C for 1h, filter, drain, add 2L of water to rinse, and calcine at 650°C in a 100% water vapor atmosphere for 2.5h to obtain a low sulfate rare earth modified Y-type molecular sieve, recorded as Z2.

[0107] Preparation Example 3

[0108] This preparation example provides a low sulfate rare earth modified Y-type molecular sieve, which is prepared by a preparation method comprising the following specific steps:

[0109] a. After slurrying 1000 g (dry basis weight) of NaY molecular sieve with 5 L of deionized water, add 0.407 L of YCl3 solution (Y2O3) with a concentration of 246 g / L 3+ 0.513 mol) was subjected to rare earth ion exchange (temperature was 60° C., pH was 4.2, and time was 1 h) to obtain a rare earth ion exchange slurry; wherein the content of YCl3 calculated as Y2O3 in the NaY molecular sieve calculated on a dry basis was 5.97 wt%;

[0110] b. Adding (32 g, 0.225 mol) ammonium oxalate monohydrate can make 1.7 wt% of Y in the above rare earth ion exchange slurry 3+ Performing a first precipitation (temperature of 60° C., time of 0.5 h) to obtain a first precipitation slurry;

[0111] c. Filter the first precipitate slurry, drain it, add 1.389L of 180g / L ammonium sulfate aqueous solution, exchange at 60°C for 1.5h, drain it, add 3L of water for elution, and then roast it at 680°C in a 100% water vapor atmosphere for 1.5h to obtain a cross-baked molecular sieve dry powder;

[0112] d. After slurrying the above 1000 g (dry basis) cross-linked and roasted molecular sieve powder with 5 L of deionized water, (22.6 g, 0.16 mol) of ammonium oxalate monohydrate was added to make 1.2 wt% of Y in the above cross-linked and roasted molecular sieve powder. 3+ After the second precipitation (temperature is 25°C, time is 0.5h), 1.389L of 180g / L ammonium sulfate aqueous solution was added, exchanged at 50°C for 1h, filtered, drained, rinsed with 3L of water, and calcined at 650°C in a 100% water vapor atmosphere for 2h to obtain a low sulfate rare earth modified Y-type molecular sieve, recorded as Z3.

[0113] Preparation Example 4

[0114] This preparation example provides a low sulfate rare earth modified Y-type molecular sieve, which is prepared by a preparation method comprising the following specific steps:

[0115] a. After slurrying 1000g (dry basis weight) of NaY molecular sieve with 5L of deionized water, add 0.43L of mixed RECl3 solution with a concentration of 326g / L (in terms of RE2O3) (the weight ratio of Ce2O3 to La2O3 is 6:4, RE 3+0.9287 mol) was subjected to rare earth ion exchange (temperature was 60° C., pH was 3.8, and time was 1 h) to obtain a rare earth ion exchange slurry; wherein the content of RECl3 calculated as RE2O3 in the NaY molecular sieve calculated on a dry basis was 14 wt%;

[0116] b. Add (25.6 g, 0.18 mol) of ammonium oxalate monohydrate and then add 5 mL of 28% industrial ammonia water to make 2.4 wt% of RE in the rare earth ion exchange slurry 3+ Performing a first precipitation (temperature of 60° C., time of 0.5 h) to obtain a first precipitation slurry;

[0117] c. Filter the first precipitate slurry, drain it, add 1.222L of 180g / L ammonium sulfate aqueous solution, exchange at 100°C for 0.5h, drain it, add 5L of water for elution, and then roast it at 580°C in a 100% water vapor atmosphere for 2h to obtain a cross-baked molecular sieve dry powder;

[0118] d. After slurrying the above 1000 g (dry basis) cross-linked and roasted molecular sieve powder with 5 L of deionized water, add (18 g, 0.187 mol) of ammonium carbonate to make 1.8 wt% of RE in the above cross-linked and roasted molecular sieve powder. 3+ After the second precipitation (temperature is 25°C, time is 0.5h), add 1L of 120g / L ammonium sulfate aqueous solution, exchange at 25°C for 1h, filter, drain, add 4L of water for rinsing, and calcine at 680°C in a 100% water vapor atmosphere for 2h to obtain a low sulfate rare earth modified Y-type molecular sieve, recorded as modified molecular sieve Z4.

[0119] Preparation Example 5

[0120] This preparation example provides a low sulfate rare earth modified Y-type molecular sieve, which is prepared by a preparation method comprising the following specific steps:

[0121] The method of Preparation Example 1 was followed, except that in step b, (32 g, 0.225 mol) ammonium oxalate monohydrate was replaced with (12.8 g, 0.09 mol) ammonium oxalate monohydrate, so that 1 wt% of La in the rare earth ion exchange slurry 3+ The first precipitation was carried out (temperature was 80° C., time was 0.5 h); other conditions were the same, and a low sulfate rare earth modified Y-type molecular sieve was obtained, which was recorded as Z5.

[0122] Preparation Example 6

[0123] This preparation example provides a low sulfate rare earth modified Y-type molecular sieve, which is prepared by a preparation method comprising the following specific steps:

[0124] The method of Preparation Example 1 was followed, except that in step d, (25.6 g, 0.18 mol) of ammonium oxalate monohydrate was replaced with (6.4 g, 0.045 mol) of ammonium oxalate monohydrate, so that 0.5 wt% of La in the above cross-baked molecular sieve dry powder 3+ The second precipitation was carried out (temperature was 25° C., time was 0.5 h); other conditions were the same, and a low sulfate rare earth modified Y-type molecular sieve was obtained, which was recorded as Z6.

[0125] Comparative Preparation Example 7

[0126] This comparative preparation example provides a rare earth modified Y-type molecular sieve, which is prepared according to the method disclosed in CN200610087535.2. The preparation method includes:

[0127] Take 1000g (dry basis weight) of NaY molecular sieve, slurry it with 8L of deionized water, add 0.385L of LaCl3 solution with a concentration of 312g / L (calculated as La2O3), add 240g of aluminum sulfate, exchange at 90°C for 1h, add 75g of ammonium bicarbonate, stir at constant temperature for 0.25h, filter, rinse with 5L of water, and then roast the filter cake at 600°C and 100% water vapor atmosphere for 2 hours to obtain a cross-baked molecular sieve dry powder;

[0128] Take 1000 g (dry basis weight) of the cross-baked molecular sieve powder, slurry it with 6 L of deionized water, add 300 g of ammonium sulfate, exchange it at 75°C for 1 h, filter it, rinse it with 6 L of water, and dry the filter cake to obtain a rare earth modified molecular sieve, which is recorded as DZ1.

[0129] Comparative Preparation Example 8

[0130] This comparative preparation example provides a rare earth modified Y-type molecular sieve, which is prepared by a preparation method comprising the following specific steps:

[0131] According to the method of Preparation Example 1, except that in step d, no (32 g, 0.225 mol) ammonium oxalate monohydrate was added, and other conditions were the same, a rare earth modified molecular sieve was obtained, which was recorded as DZ2.

[0132] Comparative Preparation Example 9

[0133] This comparative preparation example provides a rare earth modified Y-type molecular sieve, which is prepared by a preparation method comprising the following specific steps:

[0134] According to the method of Preparation Example 2, except that in step b, no (25.6 g, 0.18 mol) ammonium oxalate monohydrate was added, and other conditions were the same, a rare earth modified molecular sieve was obtained, which was recorded as DZ3.

[0135] Comparative Preparation Example 10

[0136] This comparative preparation example provides a rare earth modified Y-type molecular sieve, which is prepared by a preparation method comprising the following specific steps:

[0137] The method of Preparation Example 4 was followed, except that in step b, (25.6 g, 0.18 mol) of ammonium oxalate monohydrate and 5 mL of 28% industrial ammonia water were not added, and in step d, (18 g, 0.187 mol) of ammonium carbonate was not added. Other conditions were the same to obtain a rare earth modified molecular sieve, which was recorded as DZ4.

[0138] The physical properties of the rare earth modified Y-type molecular sieves (Z1-Z6 and DZ1-DZ4) prepared in Preparation Example 1-Preparation Example 6 and Comparative Preparation Example 7-Comparative Preparation Example 10 are listed in Table 1.

[0139] Table 1

[0140]

[0141]

[0142] It can be seen from the data in Table 1 that, compared with Comparative Preparation Examples 7 to 10, the rare earth modified Y-type molecular sieve prepared by the modification process provided by the present invention has a higher rare earth utilization rate, a lower sulfate content and a higher crystallinity.

[0143] Compared with Preparation Example 5, the modified Y-type molecular sieve obtained in Preparation Example 1 has a lower sulfate content and a slightly higher crystallinity by adjusting the dosage of the first precipitant so that the content of rare earth ions in the first precipitate is within the preferred protection range.

[0144] Compared with Preparation Example 6, Preparation Example 1 adjusts the amount of the second precipitant so that the content of rare earth ions in the second precipitate is within the preferred protection range, and the modified Y-type molecular sieve obtained also has a lower sulfate content and a slightly higher crystallinity.

[0145] Test Example 1

[0146] In this test example, the rare earth modified Y-type molecular sieves (Z1-Z6 and DZ1-DZ4) prepared in Preparation Example 1-Preparation Example 6 and Comparative Preparation Example 7-Comparative Preparation Example 10 are respectively subjected to hydrothermal stability tests, including: 100g (dry basis) of rare earth modified Y-type molecular sieves (Z1-Z6 and DZ1-DZ4) are respectively tableted, crushed into 20-40 mesh particles, aged for 10 hours under 100% water vapor and 800°C in a fixed bed hydrothermal treatment device, and then the micro-activity index (MA) is measured on a catalytic cracking automatic micro-reaction activity assessor. The reaction raw material is Dagang light diesel, the reaction temperature is 460°C, the reaction time is 70 seconds, the catalyst loading is 5.0 grams, the catalyst-oil weight ratio is 3.2, and the total conversion rate is taken as the micro-reaction activity. The test results are listed in Table 2.

[0147] Table 2

[0148]

[0149]

[0150] It can be seen from the data in Table 2 that, compared with Comparative Preparation Examples 7 to Comparative Preparation Examples 10, the rare earth modified Y-type molecular sieves prepared in Preparation Examples 1 to Preparation Examples 6 have significantly higher microreaction activity (i.e., higher MA1 values) after aging for 10 hours under 100% water vapor and 800°C conditions, compared with Comparative Preparation Examples 7 to 10. Therefore, the rare earth modified Y-type molecular sieve prepared by the modification process provided by the present invention has better hydrothermal stability and cracking activity.

[0151] Example 1

[0152] This embodiment provides a propylene catalytic cracking catalyst, which is prepared by a preparation method comprising the following specific steps:

[0153] 1) Mixing the low sulfate rare earth modified Y-type molecular sieve Z1, P modified ZSM-5, aluminum sol, acidified pseudo-boehmite, kaolin and water at 25° C. for 1 hour to obtain a slurry with a solid content of 45wt%; wherein the weight ratio of the low sulfate rare earth modified Y-type molecular sieve Z1, P modified ZSM-5, aluminum sol, acidified pseudo-boehmite and kaolin is 32:5:8.5:12:42.5;

[0154] 2) the slurry is homogenized, spray-formed, and calcined in air at 450° C. for 30 min to obtain a Na-containing catalyst;

[0155] 3) Mixing the Na-containing catalyst and water to form a slurry containing the catalyst precursor (Na-containing catalyst) with a solid content of 20 wt%, and then mixing it with diammonium hydrogen phosphate to perform sodium reduction modification, and then filtering, washing with water 5 times (the washing temperature is 85° C., the time is 0.2 h), and drying at 100° C. for 12 h to obtain a high-yield propylene catalytic cracking catalyst, which is recorded as C1;

[0156] Among them, the weight ratio of diammonium hydrogen phosphate (calculated as P2O5) and the slurry containing the catalyst precursor calculated as catalyst precursor, that is, the Na-containing catalyst, is 1.3:100, that is, the weight ratio of diammonium hydrogen phosphate (calculated as P2O5) and the Na-containing catalyst dry basis is 1.3:100.

[0157] In C1, Na2O + The content is 0.12wt%, and the P2O5 content is 1.26wt%.

[0158] Example 2

[0159] This embodiment provides a propylene catalytic cracking catalyst, which is prepared by a preparation method comprising the following specific steps:

[0160] 1) Mixing the low sulfate rare earth modified Y-type molecular sieve Z2, P modified ZSM-5, aluminum sol, acidified pseudo-boehmite, kaolin and water at 25° C. for 1 hour to obtain a slurry with a solid content of 45wt%; wherein the weight ratio of the low sulfate rare earth modified Y-type molecular sieve Z2, P modified ZSM-5, aluminum sol, acidified pseudo-boehmite and kaolin is 38:5:10:10:37;

[0161] 2) The slurry is homogenized, spray-formed, and calcined in air at 470° C. for 20 min to obtain a Na-containing catalyst;

[0162] 3) Mixing the Na-containing catalyst and water to form a slurry containing the catalyst precursor (Na-containing catalyst) with a solid content of 25 wt%, and then mixing it with diammonium hydrogen phosphate to perform sodium reduction modification, and then filtering it in sequence, washing it with water 8 times (the washing temperature is 70° C., and the time is 0.25 h), and drying it at 120° C. for 8 h to obtain a high-yield propylene catalytic cracking catalyst, which is recorded as C2.

[0163] Among them, the weight ratio of diammonium hydrogen phosphate (calculated as P2O5) and the slurry containing the catalyst precursor calculated as catalyst precursor, that is, the Na-containing catalyst, is 2.1:100, that is, the weight ratio of diammonium hydrogen phosphate (calculated as P2O5) and the Na-containing catalyst dry basis is 2.1:100.

[0164] In C2, Na2O + The content is 0.09wt%, and the P2O5 content is 2.08wt%.

[0165] Example 3

[0166] This embodiment provides a propylene catalytic cracking catalyst, which is prepared by a preparation method comprising the following specific steps:

[0167] 1) Mixing the low sulfate rare earth modified Y-type molecular sieve Z3, P modified ZSM-5, aluminum sol, acidified pseudo-boehmite, halloysite and water at 25° C. for 1 hour to obtain a slurry with a solid content of 45wt%; wherein the weight ratio of Z3, P modified ZSM-5, aluminum sol, acidified pseudo-boehmite and halloysite is 28:5:5.5:18:43.5;

[0168] 2) the slurry is homogenized, spray-formed, and calcined in air at 460° C. for 35 min to obtain a Na-containing catalyst, i.e., a catalyst precursor;

[0169] 3) Mixing the Na-containing catalyst and water to form a slurry containing the catalyst precursor with a solid content of 20 wt%, and then mixing it with diammonium hydrogen phosphate to carry out sodium reduction modification, and then filtering it in sequence, washing it with water 5 times (the washing temperature is 95° C., and the time is 0.3 h), and drying it at 110° C. for 10 h to obtain a high-yield propylene catalytic cracking catalyst, which is recorded as C3.

[0170] The weight ratio of diammonium hydrogen phosphate (calculated as P2O5) to the slurry containing the catalyst precursor calculated as the catalyst precursor is 2.5:100, that is, the weight ratio of diammonium hydrogen phosphate (calculated as P2O5) to the dry basis of the Na-containing catalyst is 2.5:100.

[0171] In C3, Na2O + The content is 0.06wt%, and the P2O5 content is 2.39wt%.

[0172] Example 4

[0173] This embodiment provides a propylene catalytic cracking catalyst, which is prepared by a preparation method comprising the following specific steps:

[0174] 1) Mixing the low sulfate rare earth modified Y-type molecular sieve Z4, P modified ZSM-5, aluminum sol, acidified pseudo-boehmite, kaolin and water at 25° C. for 1 hour to obtain a slurry with a solid content of 45wt%; wherein the weight ratio of Z4, P modified ZSM-5, aluminum sol, acidified pseudo-boehmite and kaolin is 33:5:7:20:35;

[0175] 2) the slurry is homogenized, spray-formed, and calcined in air at 450°C for 30 min to obtain a Na-containing catalyst, i.e., a catalyst precursor;

[0176] 3) Mixing the Na-containing catalyst and water to form a slurry containing the catalyst precursor with a solid content of 20 wt%, and then mixing it with diammonium hydrogen phosphate to perform sodium reduction modification, and then filtering it in sequence, washing it with water 6 times (the washing temperature is 35° C., and the time is 0.3 h), and drying it at 110° C. for 10 h to obtain a high-yield propylene catalytic cracking catalyst, which is recorded as C4.

[0177] The weight ratio of diammonium hydrogen phosphate (calculated as P2O5) to the slurry containing the catalyst precursor calculated as the catalyst precursor is 1.7:100, that is, the weight ratio of diammonium hydrogen phosphate (calculated as P2O5) to the dry basis of the Na-containing catalyst is 1.7:100.

[0178] In C4, Na2O + The content is 0.10wt%, and the P2O5 content is 1.67wt%.

[0179] Example 5

[0180] This embodiment provides a propylene catalytic cracking catalyst, which is prepared by a preparation method comprising the following specific steps:

[0181] According to the method of Example 1, except that Z1 is replaced by Z5 in step 1), and other conditions are the same, a catalytic cracking catalyst with high yield of propylene is obtained, which is recorded as C5.

[0182] In C5, Na2O + The content is 0.14wt%, and the P2O5 content is 1.28wt%.

[0183] Example 6

[0184] This embodiment provides a propylene catalytic cracking catalyst, which is prepared by a preparation method comprising the following specific steps:

[0185] According to the method of Example 1, except that Z1 is replaced by Z6 in step 1), and other conditions are the same, a catalytic cracking catalyst with high yield of propylene is obtained, which is recorded as C6.

[0186] In C6, Na2O + The content is 0.13wt%, and the P2O5 content is 1.29wt%.

[0187] Comparative Example 1

[0188] This comparative example provides a propylene catalytic cracking catalyst, which is prepared by a preparation method comprising the following specific steps:

[0189] 1) Mixing the rare earth modified molecular sieve DZ1, P modified ZSM-5, aluminum sol, acidified pseudo-boehmite, kaolin and water at 25° C. for 1 hour to obtain a slurry with a solid content of 45wt%; wherein the weight ratio of the rare earth modified molecular sieve DZ1, P modified ZSM-5, aluminum sol, acidified pseudo-boehmite and kaolin is 34:5:9:10:42;

[0190] 2) sequentially homogenizing, spraying and calcining the slurry at 450° C. for 30 min to obtain a Na-containing catalyst, i.e., a catalyst precursor;

[0191] 3) mixing the Na-containing catalyst and water to form a slurry containing the catalyst precursor with a solid content of 20 wt%, and then mixing it with diammonium hydrogen phosphate to perform sodium reduction modification, and then filtering, washing with water 4 times (the washing temperature is 50° C., and the time is 0.25 h), and drying at 105° C. for 10 h to obtain a propylene catalytic cracking catalyst, which is recorded as DC1;

[0192] The weight ratio of diammonium hydrogen phosphate (calculated as P2O5) to the slurry containing the catalyst precursor calculated as the catalyst precursor is 1.8:100, that is, the weight ratio of diammonium hydrogen phosphate (calculated as P2O5) to the dry basis of the Na-containing catalyst is 1.8:100.

[0193] In DC1, Na2O + The content is 0.21wt%, and the P2O5 content is 1.75wt%.

[0194] Comparative Example 2

[0195] This comparative example provides a propylene catalytic cracking catalyst, which is prepared by a preparation method comprising the following specific steps:

[0196] 1) Mixing the rare earth modified molecular sieve DZ2, P modified ZSM-5, aluminum sol, acidified pseudo-boehmite, kaolin and water at 25° C. for 1 hour to obtain a slurry with a solid content of 45wt%; wherein the weight ratio of the rare earth modified molecular sieve DZ2, P modified ZSM-5, aluminum sol, acidified pseudo-boehmite and kaolin is 30:5:7.5:15:42.5;

[0197] 2) the slurry is homogenized, spray-formed, and calcined at 470° C. for 30 min to obtain a Na-containing catalyst, i.e., a catalyst precursor;

[0198] 3) mixing the Na-containing catalyst and water to form a slurry containing the catalyst precursor with a solid content of 20 wt%, and then mixing it with diammonium hydrogen phosphate to perform sodium reduction modification, and then filtering, washing with water 4 times (the washing temperature is 60° C., the time is 0.2 h), and drying at 120° C. for 10 h to obtain a propylene catalytic cracking catalyst, which is recorded as DC2;

[0199] The weight ratio of diammonium hydrogen phosphate (calculated as P2O5) to the slurry containing the catalyst precursor calculated as the catalyst precursor is 1.55:100, that is, the weight ratio of diammonium hydrogen phosphate (calculated as P2O5) to the dry basis of the Na-containing catalyst is 1.55:100.

[0200] In DC2, Na2O + The content is 0.22wt%, and the P2O5 content is 1.45wt%.

[0201] Comparative Example 3

[0202] This comparative example provides a propylene catalytic cracking catalyst, which is prepared by a preparation method comprising the following specific steps:

[0203] 1) Mixing the rare earth modified molecular sieve DZ3, P modified ZSM-5, aluminum sol, acidified pseudo-boehmite, kaolin and water at 25° C. for 1 hour to obtain a slurry with a solid content of 45wt%; wherein the weight ratio of the rare earth modified molecular sieve DZ3, P modified ZSM-5, aluminum sol, acidified pseudo-boehmite and kaolin is 36:5:9:13:37;

[0204] 2) the slurry is homogenized, spray-formed, and calcined at 430° C. for 45 min to obtain a Na-containing catalyst, i.e., a catalyst precursor;

[0205] 3) Mixing the Na-containing catalyst with water to form a slurry containing the catalyst precursor with a solid content of 20 wt%, and then mixing it with diammonium hydrogen phosphate to perform sodium reduction modification, and then filtering, washing with water 6 times (the washing temperature is 40° C., and the time is 0.3 h), and drying at 100° C. for 10 h to obtain a propylene catalytic cracking catalyst, which is recorded as DC3;

[0206] The weight ratio of diammonium hydrogen phosphate (calculated as P2O5) to the slurry containing the catalyst precursor calculated as the catalyst precursor is 2.1:100, that is, the weight ratio of diammonium hydrogen phosphate (calculated as P2O5) to the dry basis of the Na-containing catalyst is 2.1:100.

[0207] In DC3, Na2O + The content is 0.23wt%, and the P2O5 content is 1.98wt%.

[0208] Comparative Example 4

[0209] This comparative example provides a propylene catalytic cracking catalyst, which is prepared by a preparation method comprising the following specific steps:

[0210] The method of Example 1 is followed, except that Z1 is replaced by DZ4, and other conditions are the same, to obtain a propylene catalytic cracking catalyst, which is recorded as DC4.

[0211] In DC4, Na2O + The content is 0.18wt%, and the P2O5 content is 1.27wt%.

[0212] Test Example 2

[0213] This test example tests the reaction performance of the catalytic cracking catalysts (C1-C6 and DC1-DC4) prepared in Examples 1-6 and Comparative Examples 1-4, respectively, including:

[0214] The above-mentioned catalytic cracking catalysts (C1-C6 and DC1-DC4) and the feedstock oil of the 3 million heavy oil catalytic unit of Lanzhou Petrochemical were added into the ACE heavy oil microreactor respectively, and a catalytic cracking reaction was carried out (the temperature was 530°C, the catalyst-oil ratio was 5, that is, the weight ratio of the catalytic cracking catalyst to the feedstock oil of the 3 million heavy oil catalytic unit of Lanzhou Petrochemical was 5:1), and a catalytic cracking product was obtained after the reaction was completed;

[0215] Among them, the catalytic cracking products include: dry gas, liquefied gas, gasoline, diesel, heavy oil and coke. The test results are listed in Table 3.

[0216] Table 3

[0217]

[0218]

[0219] Note: 1- conversion rate of crude oil of 3 million tons heavy oil catalytic unit of Lanzhou Petrochemical; 2- refers to the sum of the yields of liquefied gas, gasoline and diesel.

[0220] It can be seen from the data in Table 3 that, compared with Comparative Examples 1 to 4, the catalytic cracking catalysts prepared in Examples 1 to 6 of the present invention have excellent heavy oil cracking activity, high propylene production performance and high value-added product selectivity, that is, they have higher heavy oil conversion rate, propylene yield and total liquid yield.

[0221] The above is only a specific embodiment of the present invention, and cannot be used to limit the scope of the invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the protection scope of the patent of the present invention, should still fall within the scope of this patent. In addition, the technical features of the present invention can be freely combined with each other, with each other and with each other, and with each other.

Claims

1. A method for preparing a propylene-producing catalytic cracking catalyst, characterized in that: The preparation method comprises: (1) Preparation of low sulfate rare earth modified Y-type molecular sieve: Step 1: exchanging rare earth ions with Na-type molecular sieve to obtain rare earth ion slurry; Step 2: adding a first precipitant to cause a first precipitation of rare earth ions in the rare earth ion exchange slurry to obtain a first precipitated slurry; Step 3: The first precipitated slurry is filtered, subjected to a first ammonium sulfate exchange, washed with water, and calcined in sequence to obtain a cross-linked and calcined molecular sieve dry powder; Step 4: slurrying the cross-linked and roasted molecular sieve powder with water, adding a second precipitant to cause a second precipitation of rare earth ions in the cross-linked and roasted molecular sieve powder, and then sequentially performing a second ammonium sulfate exchange, a second water washing, and a second roasting to obtain a low sulfate rare earth modified Y-type molecular sieve; (2) Catalyst molding: The Na-containing catalyst is prepared by fully mixing water, low sulfate rare earth modified Y molecular sieve, ZSM-5 molecular sieve, clay and binder, and then homogenizing, spray drying and third calcining. (3) Modification of phosphorus-containing substances to reduce sodium content: Water and Na-containing catalyst particles are mixed and slurried, and then phosphorus-containing substances are added to modify the Na-containing catalyst to reduce sodium. The catalyst is then filtered, washed with water, and dried to obtain a high-yield propylene catalytic cracking catalyst.

2. The preparation method according to claim 1, characterized in that In step 1, the rare earth ion exchange conditions include: temperature of 25-180° C., preferably 50-80° C.; pH of 2.8-6.5, preferably 3.5-4.5; time of 0.3-3.5 h, preferably 0.5-1.5 h; Preferably, the rare earth ion exchange process comprises: mixing the Na-type molecular sieve and water, and then adding a soluble rare earth salt to perform the rare earth ion exchange; More preferably, the weight ratio of the Na-type molecular sieve to water is 1:1.5-30, preferably 1:2-5; Still more preferably, the content of the soluble rare earth salt calculated as oxide in the Na-type molecular sieve calculated on a dry basis is 1-20 wt%, preferably 6-16 wt%; Still more preferably, the soluble rare earth salt is selected from one or a combination of soluble nitrates and chlorides of lanthanum, cerium and yttrium; Still more preferably, the silicon to aluminum ratio of the Na-type molecular sieve is 2-100, preferably 2-50; Further preferably, the Na-type molecular sieve is selected from at least one of NaY molecular sieve, NaHY molecular sieve, NaUSY molecular sieve, NaREHY molecular sieve, NaREUSY molecular sieve, Naβ molecular sieve, NaHβ molecular sieve, NaREHβ molecular sieve, NaX molecular sieve, NaREX molecular sieve and NaHX molecular sieve, preferably selected from NaY molecular sieve and / or NaHY molecular sieve.

3. The preparation method according to claim 1, characterized in that In step 2, the amount of the first precipitant is such that the content of rare earth ions in the Na-type molecular sieve is 1-4 wt% by molar ratio after the first precipitation, preferably such that the content of rare earth ions in the Na-type molecular sieve is 1.5-2.5 wt% by molar ratio after the first precipitation; Preferably, the first precipitant is selected from at least one of ammonium oxalate, ammonium carbonate, ammonium bicarbonate, aqueous ammonia, urea and ammonium acetate, preferably selected from at least one of ammonium oxalate, ammonium carbonate, ammonium bicarbonate and aqueous ammonia; Preferably, the conditions for the first precipitation include: a temperature of 25-180° C., preferably 50-80° C.; and a time of 0.1-5 h, preferably 0.1-2 h.

4. The preparation method according to claim 1, characterized in that In step 3, the first ammonium sulfate exchange process includes: exchanging the filtered product with the first ammonium sulfate aqueous solution; Preferably, the weight ratio of the first aqueous ammonium sulfate solution to the Na-type molecular sieve is 5-50:100, preferably 10-25:100, calculated as ammonium sulfate; Preferably, the concentration of ammonium sulfate in the first aqueous ammonium sulfate solution is 20-400 g / L, preferably 120-250 g / L; Preferably, the conditions for the first ammonium sulfate exchange include: temperature of 15-150°C, preferably 50-80°C; time of 0.1-5h, preferably 0.5-2h; Preferably, the first ammonium sulfate exchange is carried out by tank delivery, belt delivery, or tank delivery and belt delivery simultaneously; preferably, tank delivery.

5. The preparation method according to claim 1 or 4, characterized in that In step 3, the amount of water used in the first water washing is 1-8 times, preferably 2-5 times, the weight of the Na-type molecular sieve; Preferably, the conditions for the first calcination include: 100% water vapor atmosphere; temperature of 400-700° C., preferably 500-650° C.; time of 0.1-5 h, preferably 0.5-3 h.

6. The preparation method according to claim 1, characterized in that In step 4, the amount of the second precipitant is such that the content of the rare earth ions in the cross-roasted molecular sieve dry powder is 0.5-3wt% by molar ratio after the second precipitation, preferably such that the content of the rare earth ions in the cross-roasted molecular sieve dry powder is 1-2wt% by molar ratio after the second precipitation; Preferably, the second precipitant is selected from at least one of ammonium oxalate, ammonium carbonate, ammonium bicarbonate, aqueous ammonia, urea and ammonium acetate, preferably selected from at least one of ammonium oxalate, ammonium carbonate, ammonium bicarbonate and aqueous ammonia; Preferably, the conditions for the second precipitation include: temperature of 15-40°C, preferably 20-30°C; time of 0.1-5h, preferably 0.1-2h; Also preferably, the weight ratio of the cross-calcined molecular sieve dry powder to water is 1:1.5-30, preferably 1:2-5.

7. The preparation method according to claim 1 or 6, characterized in that In step 4, the second ammonium sulfate exchange process includes: exchanging the second precipitated product with the second ammonium sulfate aqueous solution; Preferably, the weight ratio of the second ammonium sulfate aqueous solution to the cross-calcined molecular sieve dry powder is 5-50:100, preferably 10-25:100, calculated as ammonium sulfate; Preferably, the concentration of ammonium sulfate in the second aqueous ammonium sulfate solution is 20-400 g / L, preferably 120-250 g / L; Preferably, the conditions for the second ammonium sulfate exchange include: temperature of 20-85°C, preferably 50-80°C; time of 0.1-5h, preferably 0.1-2h; Preferably, the second ammonium sulfate exchange is carried out by tank delivery, belt delivery, or tank delivery and belt delivery simultaneously; preferably, tank delivery; Preferably, the amount of water used in the second water washing is 1-8 times, preferably 2-5 times, the weight of the cross-linked and roasted molecular sieve dry powder; Preferably, the conditions for the second calcination include: 100% water vapor atmosphere; temperature of 400-700° C., preferably 550-680° C.; time of 0.1-10 h, preferably 0.5-5 h; Preferably, in the low sulfate rare earth modified Y-type molecular sieve, SO4 2- The content is ≤1.0 wt%, more preferably ≤0.5 wt%, and further preferably 0.01-0.45 wt%.

8. The preparation method according to claim 1, characterized in that Step (2) catalyst shaping comprises: Based on 100 parts by dry basis of the Na-containing catalyst, water, 28-42 parts of a low-sulfate rare earth modified Y-type molecular sieve, 2-15 parts of a ZSM-5 molecular sieve, 30-65 parts of clay, and 6.5-30 parts of a binder are thoroughly mixed to form a slurry with a solid content of 25-50 wt%, which is then homogenized, spray-formed, and calcined for a third time to obtain the Na-containing catalyst; Preferably, based on 100 parts of the dry mass of the catalyst, water, 28-38 parts of low sulfate rare earth modified Y-type molecular sieve, 3-8 parts of ZSM-5 molecular sieve, 35-50 parts of clay, and 7-27 parts of a binder are fully mixed to form a slurry with a solid content of 35-45wt%, which is then homogenized, spray-formed, and calcined for the third time to obtain a Na-containing catalyst.

9. The preparation method according to claim 1 or 8, characterized in that The ZSM-5 molecular sieve includes at least one of HZSM-5 and phosphorus-modified ZSM-5.

10. The preparation method according to claim 1 or 8, characterized in that The clay comprises at least one of kaolin, halloysite, porphyrite, diatomite and vesicle stone.

11. The preparation method according to claim 1 or 8, characterized in that: The binder includes at least one of aluminum sol, acidified pseudo-boehmite, acidic silica sol and phosphate aluminum sol.

12. The preparation method according to claim 1 or 8, characterized in that The conditions of the third calcination include: air atmosphere; temperature of 420-480° C.; and time of 20-50 minutes.

13. The preparation method according to claim 1, characterized in that In step (3), based on the total dry weight of the Na-containing catalyst as 100%, 1-3 wt% of a phosphorus-containing substance calculated as P2O5 is added to modify the Na-containing catalyst to reduce sodium; Preferably, based on the total dry weight of the Na-containing catalyst as 100%, 1.3-2.5 wt% of the phosphorus-containing substance calculated as P2O5 is added to modify the Na-containing catalyst to reduce sodium; Also preferably, the weight ratio of water to Na-containing catalyst particles is 0.5-35:1; Also preferably, the water washing temperature is 20-100° C. and the washing time is 0.1-0.3 h.

14. The preparation method according to claim 1 or 13, characterized in that The phosphorus-containing substance includes at least one of phosphoric acid, ammonium phosphate, diammonium hydrogen phosphate, and ammonium dihydrogen phosphate.

15. A catalytic cracking catalyst for increasing the yield of propylene, characterized in that: The high-yield propylene catalytic cracking catalyst is prepared by the preparation method of the high-yield propylene catalytic cracking catalyst according to any one of claims 1 to 14; Preferably, based on the total weight of the high-yield propylene catalytic cracking catalyst as 100%, it contains 28-42wt% of low sulfate rare earth modified Y-type molecular sieve, 2-15wt% of ZSM-5 molecular sieve, 6.5-30wt% of binder, 30-65wt% of clay and 1-3wt% of phosphorus-containing compound calculated as P2O5.

16. Use of the high-yield propylene catalytic cracking catalyst according to claim 15 in producing propylene by catalytic cracking of heavy oil.

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