Catalytic cracking catalyst capable of reducing coking as well as preparation method and application of catalytic cracking catalyst

Abstract

The invention provides a catalytic cracking catalyst capable of reducing coking and a preparation method and application thereof, and the catalytic cracking catalyst comprises the following raw materials: a porous matrix, an inorganic auxiliary agent and a molecular sieve, at least part of pores of the porous matrix are loaded with an anti-coking material, and the medium-large pore volume of the porous matrix is not less than 0.6 cm < 3 > / g; wherein the anti-coking material is obtained by performing solid-phase ball milling on pseudo-boehmite, zinc salt and magnesium salt. According to the preparation method provided by the invention, the pore structure of the catalytic cracking catalyst can be improved, and meanwhile, the coke selectivity of the catalytic cracking catalyst is improved.

Description

Technical Field

[0001] This invention relates to the field of catalytic materials, and more particularly to a catalytic cracking catalyst for reducing coking, its preparation method, and its application. Background Technology

[0002] Catalytic cracking, as the most important secondary processing method in my country's petroleum industry, plays a crucial role in the country's refining sector. During operation, catalytic cracking units remove coke deposits on the spent catalyst through coking and maintain thermal balance, directly generating a large amount of CO2. With the increasing slag blending ratio in catalytic cracking units, the contradiction between coke yield, unit processing capacity, and carbon emissions has become increasingly acute. Therefore, reducing coke yield and improving coking performance during catalytic cracking have become key research directions.

[0003] Patent CN1506161A discloses an active component of a rare earth ultrastable Y molecular sieve. This modified molecular sieve contains 8-25 wt% rare earth oxide, 0.1-3.0 wt% phosphorus, 0.3-2.5 wt% sodium oxide, crystallinity of 30-55%, and cell constant of 2.455-2.472 nm. The high rare earth content and large cell constant of this modified molecular sieve affect the coke selectivity of the molecular sieve.

[0004] CN1624079A discloses a hydrocarbon cracking catalyst containing modified octahedral zeolite. The modified zeolite has a cell constant of 2.440-2.465 nm, sodium oxide content of 2.0-6.5 wt%, phosphorus content of 0.01-3 wt%, and rare earth oxide content of 0.1-15 wt%. The catalyst containing this zeolite has good activity stability, high gasoline yield, strong heavy oil cracking ability, and strong resistance to heavy metal pollution. However, the molecular sieve in this patent has a relatively large cell constant, which will also affect the coke selectivity of the molecular sieve catalyst. Summary of the Invention

[0005] This invention provides a catalytic cracking catalyst that reduces coking. This catalyst is used in the catalytic cracking of crude oil, which facilitates the rapid diffusion of reactant and product molecules and reduces the coke production rate.

[0006] The present invention also provides a method for preparing a catalytic cracking catalyst that reduces coking, which can improve the pore structure of the catalyst material, thereby improving the coke selectivity of the catalyst.

[0007] The present invention also provides a method for improving coking in catalytic cracking processes, which utilizes the above-mentioned catalytic cracking catalyst and a specific regeneration gas to synergistically improve the coking problem in catalytic cracking processes.

[0008] In a first aspect, the present invention provides a catalytic cracking catalyst for reducing coking, the raw materials of which include: a porous matrix, inorganic additives, and molecular sieves; the porous matrix includes kaolin and an anti-coking material at least partially supported on at least a portion of the surface of the kaolin, wherein the mesopore volume of the porous matrix is ​​not less than 0.6 cm³. 3 / g; wherein the anti-coking material is obtained by solid-phase ball milling of boehmite, zinc salt and magnesium salt.

[0009] Furthermore, the mesopore volume of the porous matrix is ​​0.6 cm³. 3 / g-0.7cm 3 / g.

[0010] Furthermore, the inorganic additive is aluminum phosphate and / or silica;

[0011] And / or, the molecular sieve is one or more of HY, REY, USY, REHY, REUSY and HZSM-5.

[0012] Furthermore, the mass ratio of the anti-coking material to kaolin is 0.075-1:1.

[0013] Furthermore, the mass ratio of the porous matrix, inorganic additives, and molecular sieve is 95-180:15-35:120-200.

[0014] Furthermore, the zinc salt is calculated as zinc oxide, the magnesium salt as magnesium oxide, and the boehmite is calculated on a dry basis. The total mass ratio of the zinc salt and magnesium salt to the boehmite is 0.1-0.7:1, and the mass ratio of the zinc salt to the magnesium salt is 1-5:1.

[0015] Furthermore, the porous matrix is ​​prepared by a method comprising the following processes:

[0016] Kaolin is subjected to a first calcination and alkali treatment. The resulting solid product is mixed with anti-coking material, polymer macroporous template agent, binder, and deionized water. The mixed system is then subjected to a second calcination to obtain the porous matrix.

[0017] Furthermore, the polymer macroporous template agent is polystyrene microspheres or polymethyl methacrylate microspheres;

[0018] And / or, the temperature of the first calcination is 940-1000℃, and the time is 1-3 hours;

[0019] And / or, the secondary calcination temperature is 400-600℃ and the time is 1-3 hours;

[0020] And / or, the ball milling speed of the solid phase ball mill is 500-1000 r / min.

[0021] Secondly, the present invention provides a method for preparing the above-mentioned catalytic cracking catalyst, comprising the following steps:

[0022] Molecular sieves are added to a mixture comprising the porous matrix, binder, inorganic additives, and solvent, and the mixture is then subjected to mixing and pulping, spray drying, and three calcination processes to obtain the catalytic cracking catalyst.

[0023] Furthermore, the temperature of the three calcination treatments is 350-650℃, and the time is 1-4 hours.

[0024] Thirdly, the present invention provides a method for improving coking in catalytic cracking processes, using the above-mentioned catalytic cracking catalyst; and the regeneration gas of the catalytic cracking catalyst is a mixture of O2 and CO2, wherein the ratio of O2 to CO2 in the mixture is 0.2-1:1.

[0025] The catalytic cracking catalyst for reducing coking provided by this invention has a rich mesoporous and macroporous structure, which facilitates the rapid diffusion of reactant and product molecules and reduces coke deposition. Furthermore, at least part of the surface structure of this catalytic cracking catalyst also includes a specific anti-coking material, which can improve the problem of poor coke selectivity caused by heavy metal poisoning exacerbating the dehydrogenation reaction.

[0026] The method for improving coking in catalytic cracking processes provided by this invention utilizes the above-mentioned catalytic cracking catalyst and a specific regeneration gas to synergistically improve the coking problem in catalytic cracking processes. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below. The specific embodiments listed below are merely descriptions of the principles and features of the present invention, and the examples are only for explaining the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] In this application, the term "and / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone. A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship.

[0029] In this application, the term "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0030] In this application, the term "micropores" refers to pores with a diameter < 2 nm; the term "mesopores" refers to pores with a diameter in the range of 2-50 nm; the term "macropores" refers to pores with a diameter > 50 nm; and the term "meso-macropore material" refers to a material that includes both mesopores and macropores.

[0031] In a first aspect, the present invention provides a catalytic cracking catalyst for reducing coking, the raw materials of which include: a porous matrix, inorganic additives, and molecular sieves; the porous matrix includes kaolin and an anti-coking material at least partially supported on at least a portion of the surface of the kaolin, wherein the mesopore volume of the porous matrix is ​​not less than 0.6 cm³. 3 / g; wherein the anti-coking material is obtained by solid-phase ball milling of boehmite, zinc salt and magnesium salt.

[0032] In this invention, the porous matrix of the raw material has a very rich mesoporous and macroporous structure, which is conducive to the rapid diffusion of reactant and product molecules in the preparation of catalytic cracking catalysts and can reduce coke deposition. Inorganic additives can further expand the pores and reduce the adverse effects on the mesoporous and macroporous pores of the catalyst system during the preparation process. Secondly, with the trend of deterioration of petroleum quality, the oil slurry contains a large amount of heavy metals. Among them, heavy metal nickel will aggravate the dehydrogenation reaction, heavy metal iron will block the catalyst pores, and the formation of iron clusters on the catalyst surface can also catalyze the dehydrogenation reaction. The unsaturated hydrocarbon molecules after dehydrogenation tend to condense to form coke, which makes the coke selectivity poor. This invention can reduce the excessively high coking factor in catalytic cracking caused by heavy metals in the oil slurry by introducing anti-coking materials.

[0033] In some embodiments, the anti-coking material is loaded onto at least a portion of the inner and outer surfaces of the pores of the kaolin.

[0034] The present invention does not specifically limit the zinc and magnesium salts mentioned above. Those skilled in the art may use conventional inorganic zinc salts, such as, but not limited to, one or more mixtures selected from zinc chloride, zinc nitrate, and zinc sulfate, and conventional inorganic magnesium salts, such as, but not limited to, one or more mixtures selected from magnesium chloride, magnesium nitrate, and magnesium sulfate.

[0035] In one specific embodiment, the mass ratio of the anti-coking material to kaolin is 0.075-1:1.

[0036] When the mass ratio of kaolin to anti-coking material is within the above range, it can achieve a good anti-coking effect while taking into account cost, and avoid the anti-coking material from causing significant adverse effects on the original pore structure of kaolin. Wherein, if the kaolin has undergone pore-expanding treatment, the kaolin in the above embodiments is the pore-expanded kaolin (modified kaolin).

[0037] For example, the mass ratio of the anti-coking material to kaolin is 0.075-0.5:1 or 0.075-0.3:1.

[0038] In one specific embodiment, the volume of mesopores in the porous matrix is ​​0.6 cm³. 3 / g-0.7cm 3 / g.

[0039] In one specific embodiment, the inorganic additive is aluminum phosphate and / or silica;

[0040] And / or, the molecular sieve is one or more of HY, REY, USY, REHY, REUSY and HZSM-5.

[0041] In one specific embodiment, the ball milling speed of the solid phase ball mill is 500-1000 r / min.

[0042] The ball milling speed affects the formation of anti-coking materials to some extent. If the ball milling speed is below 500 r / min, the reaction between boehmite and zinc salt is insufficient. If the ball milling speed is above 1000 r / min, energy consumption is high, and other side reactions may occur. The invention does not specifically limit the ball milling equipment used; in one specific embodiment, Unionprocess Corporation Qingdao Lianrui Precision Machinery Co., Ltd. is used.

[0043] For example, the solid-phase ball milling treatment time can be 20-60 minutes.

[0044] In one specific embodiment, the mass ratio of the porous matrix, inorganic additives and molecular sieve is 95-180:15-35:120-200.

[0045] The addition of a porous matrix can provide the catalyst system with more mesoporous and macroporous structures and introduce anti-coking materials. Molecular sieves are the main components that provide catalytic active sites, while inorganic additives can reduce the adverse effects on the mesoporous and macroporous structures of the catalyst system during subsequent preparation. The inventors found that when the mass ratio of porous matrix, inorganic additives and molecular sieves is within the above range, the catalyst system can reduce the coking factor while having better heavy oil conversion capacity and higher yields of liquefied petroleum gas and gasoline.

[0046] In one specific embodiment, the zinc salt is calculated as zinc oxide, the magnesium salt as magnesium oxide, and the boehmite, on a dry basis, has a total zinc salt and magnesium salt to boehmite mass ratio of 0.1-0.7:1, and a zinc salt to magnesium salt mass ratio of 1-5:1. This ratio of zinc salt, magnesium salt, and boehmite forms an anti-coking material that is more beneficial for reducing coke selectivity.

[0047] In one specific embodiment, the porous matrix is ​​prepared by a method comprising the following processes:

[0048] Kaolin is subjected to a first calcination and alkali treatment. The resulting solid product is mixed with anti-coking material, polymer macroporous template agent, binder, and deionized water. The mixed system is then subjected to a second calcination to obtain the porous matrix.

[0049] The present invention does not specifically limit the temperature and time of the above-mentioned alkali treatment. Technicians can adjust them according to the actual situation. In order to save time and ensure the stability of the material pore structure, in a preferred embodiment, the temperature of the alkali treatment is 90-95°C and the treatment time is 1-3 hours.

[0050] For example, the dry basis of the kaolin after one calcination is mixed with OH in the alkaline solution. - The mass ratio is 2-11:1. Among them, the amount of alkali used in alkali treatment affects the pore structure of kaolin. If the amount of alkali is too small, the degree of pore expansion may not be sufficient. However, as the amount of alkali increases, the pore expansion effect improves. But after the amount of alkali reaches a certain level, the pore expansion of kaolin reaches its limit, and the amount of alkali no longer significantly affects the pore structure. The amount of alkali within the range of the above-described embodiments of the present invention can achieve a better pore expansion effect.

[0051] It is understandable that binders are an essential part of the porous matrix and catalyst forming process, playing an important role in helping the porous matrix and catalyst to form and enhancing the strength of the porous matrix and catalyst. The aforementioned binders include, but are not limited to, one or more of boehmite, silica, SB powder, diatomaceous earth, aluminum hydroxide, aluminum sol, silica-alumina, and alumina.

[0052] The main purpose of the polymer macroporous template agent is to further expand the pores of the solid product. For example, the polymer macroporous template agent is polystyrene microspheres or polymethyl methacrylate microspheres. More specifically, it is polystyrene microspheres or polymethyl methacrylate microspheres with a particle size of 50-100 nm and a weight-average molecular weight of 6000-20000 g / mol. The amount of polymer macroporous template agent used can be adjusted according to the required macropore volume of the porous matrix. For example, the mass ratio of the polymer macroporous template agent to the kaolin is 0.015-0.06:1.

[0053] In one specific embodiment, the temperature of the first roasting is 940-1000℃, and the time is 1-3 hours;

[0054] And / or, the secondary calcination temperature is 400-600℃, and the time is 1-3 hours.

[0055] Secondly, the present invention provides a method for preparing the above-mentioned catalytic cracking catalyst, comprising the following steps:

[0056] Molecular sieves are added to a mixture comprising the porous matrix, binder, inorganic additives, and solvent, and the mixture is then subjected to mixing and pulping, spray drying, and three calcination processes to obtain the catalytic cracking catalyst.

[0057] Furthermore, the temperature of the three calcination treatments is 350-650℃, and the time is 1-4 hours.

[0058] The amount of binder can be adjusted according to the required strength. For example, catalytic cracking catalysts may also include 3-45 parts of binder. The binders mentioned above include, but are not limited to, one or more of boehmite, silica, SB powder, diatomaceous earth, aluminum hydroxide, aluminum sol, silica-alumina, and alumina.

[0059] Thirdly, the present invention provides a method for improving coking in catalytic cracking processes, using the above-mentioned catalytic cracking catalyst; and the regeneration gas of the catalytic cracking catalyst is a mixture of O2 and CO2, wherein the ratio of O2 to CO2 in the mixture is 0.2-1:1.

[0060] For example, the regeneration temperature is 680℃-700℃, and the regeneration coking time is 10-20 minutes.

[0061] In this invention, under the same regeneration operating conditions and with the same oxygen volume fraction of 21%, replacing traditional N2 with CO2 can achieve better regeneration results and requires less coking time than conventional air regeneration, while having higher coking intensity, thereby improving oxygen utilization. In addition, replacing N2 with CO2 also increases the concentration of carbon dioxide in the regenerated flue gas, which is more conducive to CO2 enrichment.

[0062] The present invention will be further described below with reference to specific embodiments:

[0063] The present invention is further illustrated below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions in the art or as recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are all commercially available from the conventional market. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention are within the scope of protection claimed by the present invention.

[0064] The mesopore and macropore volumes of the porous matrix were determined by mercury porosimetry (analytical methods can be found in "Modern Catalysis Research Methods", edited by Xin Qin et al., Science Press, 2009).

[0065] Raw material sources: Zinc chloride, zinc nitrate, zinc sulfate, magnesium chloride, magnesium nitrate, magnesium sulfate, aluminum phosphate, and silica, all analytical grade, produced by Sinopharm Group; kaolin, sodium hydroxide solution (NaOH content approximately 14 wt%), boehmite, aluminum sol (Al2O3 content approximately 19.4 wt%), polystyrene microspheres, and polymethyl methacrylate microspheres, produced by Lanzhou Petrochemical Company; HY, REY, USY, REHY, REUSY, and HZSM-5 are all produced by Lanzhou Petrochemical Company.

[0066] The ball milling used in the following experiments was performed using a ball mill from Unionprocess Qingdao Lianrui Precision Machinery Co., Ltd.

[0067] Example 1

[0068] This example provides a catalytic cracking catalyst for reducing coking, the raw materials of which include: a porous matrix, inorganic additives, and molecular sieves; at least a portion of the pores of the porous matrix are loaded with anti-coking materials, and the mesopore volume of the porous matrix is ​​not less than 0.6 cm³. 3 / g.

[0069] Its preparation method includes the following steps:

[0070] 1) Kaolin was calcined at 950℃ for 2.5 hours, and then 560g of dry kaolin and 1255g of alkali solution were treated at 95℃ for 2 hours. After filtration, washing and drying, modified kaolin was obtained.

[0071] 2) Mix 75g of dry boehmite, 22g of zinc chloride, and 20g of magnesium sulfate evenly, and then mechanically ball-mill for 22 minutes at a speed of 600r / min to obtain an anti-coking material;

[0072] 3) The above-mentioned modified kaolin 265g, anti-coking material 132g, polystyrene microspheres 5g (particle size 50nm, weight average molecular weight 14000g / mol), aluminum sol 73g and deionized water are mixed and pulped, and then calcined at 470℃ for 2.5 hours to obtain porous matrix C1.

[0073] 4) Mix 150g of porous matrix C1, 160g of pseudoboehmite, 1580g of deionized water, 15g of silica, 50g of USY molecular sieve, and 75g of HZSM-5 molecular sieve evenly, spray dry, and calcine at 400℃ for 2 hours three times to obtain catalyst F1.

[0074] Example 2

[0075] This example provides a catalytic cracking catalyst for reducing coking, the raw materials of which include: a porous matrix, inorganic additives, and molecular sieves; at least a portion of the pores of the porous matrix are loaded with anti-coking materials, and the mesopore volume of the porous matrix is ​​not less than 0.6 cm³. 3 / g.

[0076] Its preparation method includes the following steps:

[0077] 1) Kaolin was calcined at 980℃ for 3 hours, and then 135g of dry calcined kaolin and 435g of alkaline solution were treated at 93℃ for 3.5 hours. After filtration, washing and drying, modified kaolin was obtained.

[0078] 2) Mix 92g of boehmite dry basis, 46g of zinc sulfate, and 45g of magnesium chloride evenly, and then mechanically ball-mill for 21 minutes at a speed of 1000r / min to obtain anti-coking material;

[0079] 3) The above-mentioned modified kaolin 96g, anti-coking material 80g, polymethyl methacrylate microspheres 4.8g (particle size 80nm, weight average molecular weight 8000g / mol), aluminum sol 44g and deionized water are mixed and pulped, and then calcined at 490℃ for 2.5 hours to obtain the porous matrix C2.

[0080] 4) Mix 98g of the above porous matrix C2 with 115g of aluminum sol, 680g of deionized water, 35g of aluminum phosphate, 58g of HY molecular sieve, and 65g of REY molecular sieve until uniform, spray dry, and calcine at 650℃ for 1 hour three times to obtain catalyst F2.

[0081] Example 3

[0082] This example provides a catalytic cracking catalyst for reducing coking, the raw materials of which include: a porous matrix, inorganic additives, and molecular sieves; at least a portion of the pores of the porous matrix are loaded with anti-coking materials, and the mesopore volume of the porous matrix is ​​not less than 0.6 cm³.3 / g.

[0083] Its preparation method includes the following steps:

[0084] 1) Kaolin was calcined at 975℃ for 1.5 hours, and then 385g of dry calcined kaolin and 647g of alkali solution were treated at 95℃ for 4.5 hours. After filtration, washing and drying, modified kaolin was obtained.

[0085] 2) Mix 154g of boehmite dry basis with 15g of zinc chloride, 18g of zinc sulfate, 18g of magnesium chloride and 15g of magnesium sulfate evenly, and then mechanically ball-mill for 23 minutes at a speed of 800r / min to obtain anti-coking material.

[0086] 3) The above-mentioned modified kaolin 132g, anti-coking material 13g, polystyrene microspheres 5g (particle size 100nm, weight average molecular weight 6000g / mol), aluminum sol 48g and deionized water are mixed and pulped, and then calcined at 500℃ for 4 hours to obtain the porous matrix C3.

[0087] 4) Mix 165g of the porous matrix C3 with 205g of silica sol, 535g of deionized water, 12g of aluminum phosphate, 8g of silica, and 180g of REUSY molecular sieve until uniform, spray dry, and calcine at 500℃ for 2.5 hours three times to obtain catalyst F3.

[0088] Example 4

[0089] This example provides a catalytic cracking catalyst for reducing coking, the raw materials of which include: a porous matrix, inorganic additives, and molecular sieves; at least a portion of the pores of the porous matrix are loaded with anti-coking materials, and the mesopore volume of the porous matrix is ​​not less than 0.6 cm³. 3 / g.

[0090] Its preparation method includes the following steps:

[0091] 1) Kaolin was calcined at 940℃ for 3 hours, and then 560g of dry calcined kaolin and 1255g of alkali solution were treated at 95℃ for 2 hours. After filtration, washing and drying, modified kaolin was obtained.

[0092] 2) Mix 75g of boehmite dry basis, 22g of zinc chloride, and 20g of magnesium sulfate evenly, and then mechanically ball-mill for 22 minutes at a speed of 600r / min to obtain an anti-coking material;

[0093] 3) The above-mentioned modified kaolin 265g, anti-coking material 132g, polystyrene microspheres 5g (particle size 50nm, weight average molecular weight 14000g / mol), aluminum sol 73g and deionized water are mixed and pulped, and then calcined at 600℃ for 2.5 hours to obtain porous matrix C4.

[0094] 4) Mix 150g of porous matrix C1, 160g of pseudoboehmite, 1580g of deionized water, 15g of silica, 50g of USY molecular sieve, and 75g of HZSM-5 molecular sieve evenly, spray dry, and calcine at 650℃ for 2 hours three times to obtain catalyst F4.

[0095] Example 5

[0096] Same as Example 1, except that: in step 1), kaolin is calcined at 1000°C for 2 hours to finally obtain porous matrix C5 and catalyst F5.

[0097] Example 6

[0098] The preparation method of the catalytic cracking catalyst provided in this example is basically the same as that in Example 1, except that the particle size of the polystyrene microspheres is 20 nm, and the porous matrix C6 and catalyst F6 are finally obtained.

[0099] Example 7

[0100] The preparation method of the catalytic cracking catalyst provided in this example is basically the same as that in Example 1, except that the anti-coking material in step 3) is changed to 12g, and finally a porous matrix C7 and catalyst F7 are obtained.

[0101] Example 8

[0102] The preparation method of the catalytic cracking catalyst provided in this example is basically the same as that in Example 1, except that the polystyrene microspheres in step 3) are changed to 115g, and finally porous matrix C8 and catalyst F8 are obtained.

[0103] Comparative Example 1

[0104] This example provides a catalytic cracking catalyst for reducing coking, the raw materials of which include: a porous matrix, inorganic additives, and molecular sieves; the mesopore volume of the porous matrix is ​​less than 0.6 cm³. 3 / g.

[0105] Its preparation method includes the following steps:

[0106] 1) Kaolin was calcined at 950℃ for 2.5 hours, and then 560g of dry calcined kaolin and 1255g of alkali solution were treated at 95℃ for 2 hours. After filtration, washing and drying, modified kaolin was obtained.

[0107] 2) Mix 265g of the modified kaolin, 84g of boehmite (dry basis), 25g of zinc chloride, 23g of magnesium sulfate, 5g of polystyrene microspheres (particle size 50nm, weight average molecular weight 14000g / mol), 73g of alumina sol and deionized water, and slurry them. Then, calcine them at 470℃ for 2.5 hours to obtain the porous matrix D1.

[0108] 3) Mix 150g of the porous matrix D1, 160g of pseudoboehmite, 1580g of deionized water, 15g of silica, 50g of USY molecular sieve, and 75g of HZSM-5 molecular sieve evenly, spray dry, and calcine three times at 400℃ for 2 hours to obtain catalyst S1.

[0109] Comparative Example 2

[0110] This example provides a catalytic cracking catalyst for reducing coking, the raw materials of which include: a porous matrix, inorganic additives, and molecular sieves; at least a portion of the pores of the porous matrix are loaded with anti-coking materials, and the mesopore volume of the porous matrix is ​​less than 0.6 cm³. 3 / g.

[0111] Its preparation method includes the following steps:

[0112] 1) Mix 92g of boehmite dry basis, 46g of zinc sulfate, and 45g of magnesium chloride evenly, and then mechanically ball-mill for 21 minutes at a speed of 1000r / min to obtain an anti-coking material.

[0113] 2) Mix 96g of dry kaolin, 80g of anti-coking material, 4.8g of polymethyl methacrylate microspheres (particle size 80nm, weight average molecular weight 8000g / mol), 44g of aluminum sol and deionized water, and calcine at 490℃ for 2.5 hours to obtain the porous matrix D2.

[0114] 3) Mix 98g of the above porous matrix D2 with 115g of aluminum sol, 680g of deionized water, 35g of aluminum phosphate, 58g of HY molecular sieve, and 65g of REY molecular sieve until uniform, spray dry, and calcine at 650℃ for 1 hour to obtain catalyst S2.

[0115] Comparative Example 3

[0116] This example provides a catalytic cracking catalyst for reducing coking, the raw materials of which include: a porous matrix, inorganic additives, and molecular sieves; at least a portion of the pores of the porous matrix are loaded with anti-coking materials, and the mesopore volume of the porous matrix is ​​less than 0.6 cm³. 3 / g.

[0117] Its preparation method includes the following steps:

[0118] 1) Kaolin was calcined at 975℃ for 1.5 hours, and then 385g of dry calcined kaolin and 647g of alkali solution were treated at 95℃ for 4.5 hours. After filtration, washing and drying, modified kaolin was obtained.

[0119] 2) Mix 154g of boehmite dry basis, 30g of zinc chloride, and 36g of zinc sulfate evenly, and then mechanically ball-mill for 23 minutes at a speed of 800r / min to obtain an anti-coking material;

[0120] 3) Mix 132g of the modified kaolin, 13g of the anti-coking material, 48g of aluminum sol and deionized water, and slurry them. Then, calcine them at 500℃ for 4 hours to obtain the porous matrix D3.

[0121] 4) Mix 165g of the above porous matrix D3 with 205g of silica sol, 535g of deionized water, 12g of aluminum phosphate, 8g of silica, and 180g of REUSY molecular sieve until uniform, spray dry, and calcine three times at 500℃ for 2.5 hours to obtain catalyst S3.

[0122] Comparative Example 4

[0123] This example provides a catalytic cracking catalyst for reducing coking, the raw materials of which include: a porous matrix, inorganic additives, and molecular sieves; at least a portion of the pores of the porous matrix are loaded with anti-coking materials, and the mesopore volume of the porous matrix is ​​less than 0.6 cm³. 3 / g.

[0124] Its preparation method is basically the same as that in Example 1, except that the polystyrene microspheres are replaced with glucose, and the catalyst S4 is finally obtained.

[0125] Table 1. Pore volume characterization results of porous matrix

[0126]

[0127]

[0128] Test case

[0129] The catalytic activity of the catalytic cracking catalyst was tested: the selectivity of the catalyst for cracking reaction was evaluated in a small fixed fluidized bed (FFB) test unit (XGL-2, Luoyang). The catalyst was first hydrothermally treated for 10 hours at 800℃ and 100% steam. The hydrothermally treated catalyst was then evaluated for reaction selectivity in a fixed-bed fluidized bed test unit. The feedstock was Lanzhou Petrochemical catalytic feedstock, the specific properties of which are shown in Table 2. The reaction temperature was 500-535℃, and the space velocity was 12-15 h⁻¹. -1 With an agent-to-oil ratio of 5, F1-F8 and S1-S4 were evaluated on a fixed fluidized bed device, and the results are listed in Table 3.

[0130] The effect of different regeneration gases on coking properties was tested: Two sets of experiments were conducted in parallel using an apparatus that consistently tested the catalytic capacity of catalytic cracking catalysts. In one set, the regeneration mixed gas was O2 and CO2 with a volume ratio of 21:20, the regeneration temperature was 650℃, and the regeneration coking time was 25 min. The catalyst obtained after regeneration of the catalytic cracking catalyst of Example 1 was designated as FC1. In the other set, the regeneration mixed gas was air, the regeneration temperature was 650℃, and the carbon content was measured by infrared integration during the regeneration process. The regeneration coking time was 25 min. The catalyst obtained after regeneration of the catalytic cracking catalyst of Example 1 was designated as FCD1. Carbon analysis was performed on the two FC1 and FCD1. The total carbon content of FC1 was 0.3%, and the total carbon content of FCD1 was 0.65%.

[0131] Formula for calculating the scorch factor:

[0132] Coking factor (CF) = Ycoke * (100 - X) ÷ X;

[0133] Where CF is the coking factor, Ycoke is the coke yield, and X is the conversion rate.

[0134] Total carbon analysis of catalyst: A certain amount of catalyst is fully combusted in oxygen, so that all the carbon on the surface of the catalyst sample is converted into carbon dioxide and carbon monoxide. The carbon dioxide and carbon monoxide produced are measured by infrared absorption and converted into the mass percentage of the catalyst sample.

[0135] Table 2 Raw Material Properties

[0136]

[0137]

[0138] Table 3 Evaluation results of catalyst-fixed fluidized bed devices

[0139]

[0140] Note: "Light yield" in the table refers to the total yield of diesel + C5 gasoline.

[0141] As can be seen from the data above, compared with the comparative example, the catalytic cracking catalyst prepared in the example has a better heavy oil conversion capacity, a higher gasoline yield, and a lower coking factor, as demonstrated by performance evaluation. In addition, after the present invention further replaces part of the nitrogen in the air with carbon dioxide, its catalyst regeneration performance is better and its coking performance is further improved compared with conventional regenerated air.

[0142] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A catalytic cracking catalyst for reducing coking, characterized in that, Its raw materials include: a porous matrix, inorganic additives, and molecular sieves; the porous matrix includes kaolin and an anti-coking material at least partially loaded on at least a portion of the surface of the kaolin, and the mesopore volume of the porous matrix is ​​not less than 0.6 cm³. 3 / g; wherein the anti-coking material is obtained by solid-phase ball milling of boehmite, zinc salt and magnesium salt.

2. The catalytic cracking catalyst according to claim 1, characterized in that, The volume of mesopores and macropores in the porous matrix is ​​0.6 cm³. 3 / g-0.7cm 3 / g.

3. The catalytic cracking catalyst according to claim 1, characterized in that, The inorganic additive is aluminum phosphate and / or silica; And / or, the molecular sieve is one or more of HY, REY, USY, REHY, REUSY and HZSM-5.

4. The catalytic cracking catalyst according to claim 1 or 2, characterized in that, The mass ratio of the anti-coking material to kaolin is 0.075-1:

1.

5. The catalytic cracking catalyst according to claim 3, characterized in that, The mass ratio of the porous matrix, inorganic additives and molecular sieve is 95-180:15-35:120-200.

6. The catalytic cracking catalyst according to claim 1 or 2, characterized in that, The zinc salt is calculated as zinc oxide, the magnesium salt as magnesium oxide, and the pseudoboehmite is calculated on a dry basis. The total mass ratio of zinc salt and magnesium salt to pseudoboehmite is 0.1-0.7:1, and the mass ratio of zinc salt to magnesium salt is 1-5:

1.

7. The catalytic cracking catalyst according to claim 1 or 2, characterized in that, The porous matrix is ​​prepared by a method comprising the following processes: Kaolin is subjected to a first calcination and alkali treatment. The resulting solid product is mixed with anti-coking material, polymer macroporous template agent, binder, and deionized water. The mixed system is then subjected to a second calcination to obtain the porous matrix.

8. The catalytic cracking catalyst according to claim 7, characterized in that, The polymer macroporous template agent is polystyrene microspheres or polymethyl methacrylate microspheres; And / or, the temperature of the first calcination is 940-1000℃, and the time is 1-3 hours; And / or, the secondary calcination temperature is 400-600℃ and the time is 1-3 hours; And / or, the ball milling speed of the solid phase ball mill is 500-1000 r / min.

9. A method for preparing a catalytic cracking catalyst as described in any one of claims 1-8, characterized in that, Includes the following steps: Molecular sieves are added to a mixture comprising the porous matrix, binder, inorganic additives, and solvent, and the mixture is then subjected to mixing and pulping, spray drying, and three calcination processes to obtain the catalytic cracking catalyst.

10. The preparation method according to claim 9, characterized in that, The three calcination processes are carried out at a temperature of 350-650℃ for 1-4 hours.

11. A method for improving coking in catalytic cracking processes, characterized in that, The catalytic cracking catalyst according to any one of claims 1-8 is used; and the regeneration gas of the catalytic cracking catalyst is a mixture of O2 and CO2, wherein the ratio of O2 to CO2 in the mixture is 0.2-1:1.

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