A low-carbon olefin additive for heavy oil cracking, its preparation method, catalyst, and application.

Abstract

This disclosure relates to a low-carbon olefin additive for heavy oil cracking, its preparation method, and its application. The additive contains MFI molecular sieve, aluminosilicate phosphorus binder, macroporous alumina material, other inorganic binders, and clay. Based on the dry weight of the additive, the content of the MFI molecular sieve is 10-75 wt%, the content of the macroporous alumina material is 1-30 wt%, the content of the aluminosilicate phosphorus binder (calculated as oxides) is 3-35 wt%, the content of the other inorganic binders (calculated as oxides) is 1-20 wt%, and the content of the clay is 0-60 wt%. The additive of this disclosure can effectively improve the yield of liquefied petroleum gas and propylene, while promoting heavy oil cracking and reducing coke and slurry production.

Description

Technical Field

[0001] This application relates to a low-carbon olefin additive for heavy oil cracking, its preparation method, catalyst, and application. Background Technology

[0002] For most catalytic cracking units, adding catalysts is an effective technical approach to increase the production of low-carbon olefins, and the acidity of the catalyst and the shape-selective effect of the pores determine the yield of low-carbon olefins in the product.

[0003] Prior art discloses a five-membered ring high-silica zeolite catalyst for light olefins in a fluidized bed catalytic cracking unit. The catalyst comprises (a) a five-membered ring high-silica zeolite, (b) 8-24 wt% phosphorus, calculated as P2O5 based on the five-membered ring high-silica zeolite particles, and 1-10 wt% iron oxide, calculated as Fe2O3, located outside the five-membered ring high-silica zeolite framework. The catalyst is fluidizable and has an average particle size of about 20-200 micrometers. The catalyst composition can increase the yield of light olefins such as propylene in fluidized bed catalytic cracking (FCC), but increases propylene yield while decreasing gasoline yield. A cracking catalyst for increasing propylene concentration is disclosed in the prior art. This catalyst, on a dry basis, consists of 10-65 wt% modified ZSM-5 molecular sieve, 0-60 wt% clay, 15-60 wt% inorganic oxide binder, 0.5-15 wt% metal additives selected from one or more Group VIIIB metals, and 2-25 wt% phosphorus additives. The modified ZSM-5 molecular sieve is modified with phosphorus and a metal selected from Fe, Co, or Ni. Its anhydrous chemical expression, on an oxide basis, is (0-0.3)Na₂O·(0.5-5)Al₂O₃·(1.3-10)P₂O₅·(0.7-15)M x O y (70-97)SiO2, where x represents the number of atoms of M, and y represents a number required to satisfy the oxidation state of M. The metal and phosphorus additives mentioned are both based on oxides. This cracking catalyst, when applied to the catalytic cracking process of petroleum hydrocarbons, significantly increases the propylene concentration in liquefied petroleum gas (LPG) while increasing the yield and octane number of gasoline. However, gasoline yield decreases significantly, while diesel and slurry yields do not decrease. Summary of the Invention

[0004] The purpose of this disclosure is to provide a low-carbon olefin additive for heavy oil cracking, its preparation method, catalyst, and application. The additive disclosed herein can effectively improve the yield of liquefied petroleum gas and propylene, while promoting heavy oil conversion and reducing coke and slurry.

[0005] To achieve the above objectives, the first aspect of this disclosure provides a low-carbon olefin additive for heavy oil cracking, the additive comprising MFI molecular sieve, phosphorus aluminum binder, macroporous alumina material, other inorganic binders and clay;

[0006] Based on the dry weight of the additives, the content of the MFI molecular sieve is 10-75% by weight, the content of the macroporous alumina material is 1-30% by weight, the content of the phosphorus aluminum binder (calculated as oxides) is 3-35% by weight, the content of the other inorganic binders (calculated as oxides) is 1-20% by weight, and the content of the clay is 0-60% by weight.

[0007] Based on the total weight of the phosphorus aluminum binder, the phosphorus aluminum binder contains 3-15% by weight Al2O3, 15-40% by weight P2O5, and 0.1-10% by weight stabilizer; the P / Al weight ratio of the phosphorus aluminum binder is 1.6-6, the pH value is 0.5-2.5, and the QPO is [not specified]. 2 / QP0 0 The range is 1-5, where QP0 2 Indicates by 31 P-NMR spectroscopy analysis of the phosphorus aluminum binder yielded a resonance signal peak area with a chemical shift of 12 ± 2 ppm, QP0. 0 The area of ​​the resonance signal peak with a chemical shift of 0±2ppm is indicated; the average particle size of the phosphorus aluminum binder is 10-30nm;

[0008] The macroporous alumina material has a bimodal structure, with pores of 2-10 nm accounting for 20-40% of the total pore volume and pores of 10-100 nm accounting for 60-80% of the total pore volume.

[0009] Optionally, the aluminum phosphorus binder contains 3-12% by weight of Al₂O₃, 15-32% by weight of P₂O₅, and 0.5-5% by weight of stabilizer; the P / Al weight ratio of the aluminum phosphorus binder is 1.7-5.8, the pH value is 0.5-2.5, and the QPO is [not specified]. 2 / QP0 0 The content of the phosphorus aluminum binder is 1.5-5; the solid content of the phosphorus aluminum binder is 15-50% by weight.

[0010] Optionally, based on the dry weight of the additives, the content of the MFI molecular sieve is 15-65% by weight, the content of the macroporous alumina material is 2-20% by weight, the content of the phosphorus aluminum binder (calculated as oxides) is 8-32% by weight, the content of the other inorganic binders (calculated as oxides) is 2-20% by weight, and the content of the clay is 1-25% by weight.

[0011] Optionally, the other inorganic binder is one or more selected from boehmite, alumina, aluminum sol, silica-alumina sol, and silica sol;

[0012] The clay is selected from one or more of kaolin, sepiolite, attapulgite, rettoite, montmorillonite, and diatomite.

[0013] The MFI molecular sieve is selected from one or more of the following: hydrogen-type MFI molecular sieve, phosphorus-containing MFI molecular sieve, and transition metal-containing MFI molecular sieve.

[0014] A second aspect of this disclosure provides a method for preparing the adjuvant provided in the first aspect of this disclosure, the method comprising:

[0015] S1. Mix the MFI molecular sieve, the macroporous alumina material, the other inorganic binder, the clay and water, and control the pH value of the slurry to be greater than 2.5 to obtain the first slurry;

[0016] S2. After mixing the first slurry with the phosphorus aluminum binder, spray drying and calcination are carried out to obtain the additive.

[0017] Optionally, the phosphorus aluminum binder is prepared by a method comprising the following steps:

[0018] (1) Under stirring conditions at 50-95℃, aluminum source, water and stabilizer are mixed to obtain an alumina precursor solution with a solid content of 5-40% by weight.

[0019] (2) The alumina precursor solution is mixed with phosphate at 25-70℃ and under stirring conditions to obtain the aluminum phosphate binder.

[0020] Optionally, the aluminum source is selected from one or more of aluminum nitrate, aluminum sulfate, and aluminum chloride;

[0021] The phosphate is diamine hydrogen phosphate and / or ammonium dihydrogen phosphate;

[0022] The stabilizer is selected from one or more of acetic acid, glycolic acid, oxalic acid, malonic acid, malic acid, tartaric acid, succinic acid, adipic acid, maleic acid, itaconic acid, and citric acid, preferably acetic acid or citric acid.

[0023] A third aspect of this disclosure provides a catalyst comprising an auxiliary agent and an optional main catalyst, wherein the auxiliary agent is the one provided in the first aspect of this disclosure.

[0024] The third aspect of this disclosure provides the application of the catalyst provided in the first aspect of this disclosure in the catalytic cracking reaction of heavy feedstock oil.

[0025] Optionally, the conditions for the catalytic cracking reaction of the heavy feedstock oil include: a temperature of 400-600℃ and a heavy hourly space velocity of 8-120 h⁻¹. -1 The weight ratio of the agent to oil is 1-20.

[0026] Through the above technical solution, the additive disclosed herein contains a specific phosphorus-aluminum binder. This phosphorus-aluminum binder has fewer free phosphate groups and more polymerized phosphate groups, resulting in good bonding performance and a long service life. This phosphorus-aluminum binder has a synergistic effect with macroporous alumina materials and MFI molecular sieves, enabling the additive disclosed herein to effectively increase the yield of propylene and the concentration of propylene in liquefied petroleum gas, while simultaneously promoting heavy oil conversion and reducing coke and slurry production.

[0027] The additives provided by this invention are used for the conversion of heavy feedstock oils, such as high-density heavy oil, to improve the conversion rate of heavy oil, reduce coke yield, reduce slurry yield, and have a higher propylene yield.

[0028] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0029] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0030] Figure 1 These are the NMR spectra of the aluminum phosphorus binder prepared in Example 1 of this disclosure and the NMR spectra of the aluminum phosphorus binder prepared in Comparative Example 1. Detailed Implementation

[0031] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0032] The first aspect of this disclosure provides a low-carbon olefin additive for heavy oil cracking, the additive comprising MFI molecular sieve, phosphorus aluminum binder, macroporous alumina material, other inorganic binders and clay;

[0033] Based on the dry weight of the additives, the content of the MFI molecular sieve is 10-75% by weight, the content of the macroporous alumina material is 1-30% by weight, the content of the phosphorus aluminum binder (calculated as oxides) is 3-35% by weight, the content of the other inorganic binders (calculated as oxides) is 1-20% by weight, and the content of the clay is 0-60% by weight.

[0034] Based on the total weight of the phosphorus aluminum binder, the phosphorus aluminum binder contains 3-15% by weight Al2O3, 15-40% by weight P2O5, and 0.1-10% by weight stabilizer; the P / Al weight ratio of the phosphorus aluminum binder is 1.6-6, the pH value is 0.5-2.5, and the QPO is 0. 2 / QP0 0 The range is 1-5, where QP0 2 Indicates by 31 P-NMR spectroscopy analysis of the phosphorus aluminum binder yielded a resonance signal peak area with a chemical shift of 12 ± 2 ppm, QP0. 0 The area of ​​the resonance signal peak with a chemical shift of 0±2ppm is indicated; the average particle size of the phosphorus aluminum binder is 10-30nm;

[0035] The macroporous alumina material has a bimodal structure, with pores of 2-10 nm accounting for 20-40% of the total pore volume and pores of 10-100 nm accounting for 60-80% of the total pore volume.

[0036] According to this disclosure, the total pore volume is the pore volume measured according to the RIPP 151-90 method (see Petrochemical Analytical Methods, Determination of Pore Volume and Pore Size Distribution of Catalysts by Nitrogen Adsorption Capacitance Method, edited by Yang Cuiding et al., *Petrochemical Analytical Methods* (RIPP Experimental Methods), Science Press, 1990). The bimodal structure of macroporous alumina materials in this disclosure refers to the presence of two distinct peaks in the pore distribution spectrum measured by the nitrogen adsorption capacity method.

[0037] The additive disclosed herein contains a specific phosphorus-aluminum binder with fewer free phosphate groups and more polymerized phosphate groups, resulting in good binding performance and a long service life. The macroporous alumina material has a bimodal macroporous distribution, which facilitates the diffusion of heavy oil macromolecules and reactant molecules, promoting heavy oil pre-cracking and reducing coking. This phosphorus-aluminum binder has a synergistic effect with the macroporous alumina material and MFI molecular sieve, effectively increasing propylene yield and propylene content in liquefied petroleum gas, while simultaneously promoting heavy oil conversion and reducing coke and slurry production.

[0038] According to this disclosure, the average particle size of the aluminum phosphorus binder is obtained by transmission electron microscopy (TEM). Specifically, the aluminum phosphorus binder is analyzed by TEM, 100 aluminum phosphorus binder particles are randomly selected from the TEM image, and their largest diameter is measured as their particle size. The average particle size of the 100 aluminum phosphorus binder particles is calculated.

[0039] In a preferred embodiment of this disclosure, the aluminum phosphorus binder contains 3-12% by weight of Al₂O₃, 15-32% by weight of P₂O₅, and 0.1-5% by weight of stabilizer; the P / Al weight ratio of the aluminum phosphorus binder is 1.7-5.8, the pH value is 0.5-2.5, and the QPO is [not specified]. 2 / QP0 0 It ranges from 1.5 to 5.

[0040] In one specific embodiment of this disclosure, the macroporous alumina material has a bimodal structure, wherein the pore volume of pores with a diameter of 2-10 nm accounts for 20-40% of the total pore volume, preferably 21-38%, and the pore volume of pores with a diameter of 10-100 nm accounts for 60-80% of the total pore volume, preferably 61-78%.

[0041] In one specific embodiment of this disclosure, based on the dry weight of the additive, the content of the MFI molecular sieve is 15-65% by weight, the content of the macroporous alumina material is 2-20% by weight, the content of the phosphorus-aluminum binder (calculated as oxides) is 8-32% by weight, the content of the other inorganic binders (calculated as oxides) is 2-20% by weight, and the content of the clay is 1-25% by weight. More preferably, based on the dry weight of the additive, the content of the MFI molecular sieve is 20-60% by weight, the content of the macroporous alumina material is 2-10% by weight, the content of the phosphorus-aluminum binder (calculated as oxides) is 20-30% by weight, the content of the other inorganic binders (calculated as oxides) is 10-18% by weight, and the content of the clay is 5-10% by weight. The additive with the above composition has superior catalytic performance, which can further improve the yield of low-carbon olefins, promote the conversion of heavy oil, and reduce coke and slurry.

[0042] According to this disclosure, other inorganic binders can be those conventionally used by those skilled in the art in the preparation of additives. In one specific embodiment of this disclosure, the other inorganic binder is one or more selected from boehmite, alumina, aluminum sol, silica-alumina sol, and silica sol.

[0043] According to this disclosure, the clay can be any material commonly used by those skilled in the art in the preparation of additives. In one specific embodiment of this disclosure, the clay is selected from one or more of kaolin, sepiolite, attapulgite, rettoiter, montmorillonite, and diatomaceous earth.

[0044] In one specific embodiment of this disclosure, the MFI molecular sieve is selected from one or more of hydrogen-type MFI molecular sieves, phosphorus-containing MFI molecular sieves, and transition metal-containing MFI molecular sieves.

[0045] The second aspect of this disclosure provides a method for preparing the additive provided in the first aspect of this disclosure. The method includes: S1, mixing the MFI molecular sieve, the macroporous alumina material, the other inorganic binder, the clay, and water to form a slurry, controlling the pH value of the slurry to be greater than 2.5, to obtain a first slurry; S2, mixing the first slurry with the phosphorus aluminum binder, and then spray drying and calcining to obtain the additive.

[0046] The method disclosed herein can prepare an additive with superior catalytic performance, which can effectively improve the yield of low-carbon olefins (such as propylene), while promoting heavy oil conversion and reducing coke and slurry.

[0047] In one specific embodiment of this disclosure, in step S1, the MFI molecular sieve, the macroporous alumina material, the clay and water are first mixed and pulped, and then the other inorganic binders are added to the resulting mixture for further mixing and pulping to obtain the first slurry, which is beneficial to further improve the activity and strength of the additives.

[0048] According to this disclosure, spray drying is a technique well known to those skilled in the art, and specific methods will not be described in detail here. In one specific embodiment, the inlet temperature of the spray dryer can be 300-700°C, and the outlet temperature can be 80-200°C.

[0049] In one specific embodiment of this disclosure, the calcination temperature is 400-700℃, preferably 450-600℃, and the calcination time is 0.5-100 hours, preferably 0.5-10 hours.

[0050] In one specific embodiment of this disclosure, the aluminum phosphate binder is prepared by a method comprising the following steps: (1) mixing an aluminum source, water, and a stabilizer at 50-95°C with stirring to obtain an alumina precursor solution with a solid content of 5-40% by weight; (2) reacting the alumina precursor solution with phosphate at 25-70°C with stirring to obtain the aluminum phosphate binder. In one embodiment, the reaction time in step (2) can vary within a wide range, as long as the alumina precursor solution and phosphate react to form a transparent colloid, for example, 10-60 minutes.

[0051] The method disclosed herein uses a phosphorus-aluminum binder prepared from low-cost aluminum salts and phosphates. This phosphorus-aluminum binder has few free phosphate groups and many polymerized phosphate groups, resulting in good bonding performance. Furthermore, it contains a stabilizer that can effectively extend the service life of the phosphorus-aluminum binder.

[0052] In one specific embodiment of this disclosure, the aluminum source is selected from one or more of aluminum nitrate, aluminum sulfate, and aluminum chloride; the phosphate is diamine hydrogen phosphate and / or ammonium dihydrogen phosphate; the stabilizer is selected from one or more of acetic acid, glycolic acid, oxalic acid, malonic acid, malic acid, tartaric acid, succinic acid, adipic acid, maleic acid, itaconic acid, and citric acid, preferably acetic acid or citric acid.

[0053] A third aspect of this disclosure provides a catalyst comprising an auxiliary agent and an optional main catalyst, wherein the auxiliary agent is the one provided in the first aspect of this disclosure.

[0054] According to this disclosure, the catalyst can be selected according to actual needs and can be a catalytic cracking catalyst and / or catalytic pyrolysis catalyst well known to those skilled in the art.

[0055] The fourth aspect of this disclosure provides the application of the additives provided in the first aspect of this disclosure in the catalytic cracking reaction of heavy feedstock oil.

[0056] In one specific embodiment of this disclosure, the conditions for the catalytic cracking reaction of the heavy feedstock oil include: a temperature of 400-600℃, preferably 450-550℃, and a heavy hourly space velocity of 8-120 h⁻¹. -1 Preferably 8-80 hours -1 The catalyst-to-oil weight ratio is 1-20, preferably 3-15. The catalyst provided in this disclosure can be used in various existing catalytic cracking reactors, such as fixed-bed reactors, fluidized-bed reactors, riser reactors, and multi-zone reactors.

[0057] The present disclosure will be further illustrated by the following examples, but the present disclosure is not limited thereto.

[0058] When evaluating the performance of the additives disclosed herein in catalytic cracking reactions, an ACE apparatus is used for evaluation.

[0059] For details of the RIPP standard method described in this disclosure, please refer to "Analytical Methods in Petrochemical Industry", edited by Yang Cuiding et al., 1990 edition.

[0060] Nitrogen adsorption method (RIPP151-90) was used to determine the pore volume.

[0061] The properties of some of the raw materials used in the examples and comparative examples are as follows:

[0062] Boehmite is an industrial product manufactured by Shandong Aluminum Company, with a solid content of 60% by weight.

[0063] The aluminum sol is an industrial product produced by Sinopec Catalyst Qilu Branch, with an Al2O3 content of 21.5% by weight.

[0064] Kaolin is a special kaolin for additives produced by Suzhou Kaolin Company, with a solid content of 78% by weight.

[0065] Hydrochloric acid: chemically pure, concentration 36-38% by weight, produced by Beijing Chemical Plant.

[0066] MPZ molecular sieve: an industrial product produced by Sinopec Catalysts Qilu Branch, with a P2O5 content of 7.25% by weight, a Fe2O3 content of 1.95% by weight, and a crystallinity of 72%.

[0067] Macroporous alumina material: an industrial product manufactured by Shandong Aluminum Company, with a solid content of 80% by weight. The pore volume of pores with a diameter of 2-10 nm accounts for 20-40% of the total pore volume, and the pore volume of pores with a diameter of 10-100 nm accounts for 60-80% of the total pore volume.

[0068] SLA is a catalytic cracking catalyst produced by Sinopec Catalyst Qilu Branch.

[0069] The average particle size of the phosphorus aluminum binder in this disclosure was determined by transmission electron microscopy.

[0070] Preparation Examples 1-4 are examples of the preparation of the phosphorus aluminum binder disclosed herein.

[0071] Preparation Example 1

[0072] (1) Mix 0.56 kg of anhydrous aluminum sulfate with 0.25 kg of decationized water and 0.05 kg of oxalic acid, stir, and heat to 70 °C and slurry for 30 minutes to obtain an alumina precursor solution with a solid content of 39% by weight.

[0073] (2) 0.56 kg of ammonium dihydrogen phosphate was added to the alumina precursor solution prepared in step (1) while maintaining a temperature of 45°C and stirring. The mixture was then reacted at 45°C for 45 minutes until it became a transparent colloid, yielding aluminum-phosphorus binder P-1. The material ratios are shown in Table 1, and the NMR spectrum of the aluminum-phosphorus binder is shown in [Table 1]. Figure 1 .

[0074] Preparation Examples 2-4

[0075] The aluminum phosphate binder was prepared using the same method as in Preparation Example 1, except that the raw materials and their amounts were different. The specific material ratios are shown in Table 1.

[0076] Preparation of Comparative Example 1

[0077] The phosphorus aluminum inorganic binder was prepared according to the method provided in patent ZL201110180891.X. The specific method is as follows:

[0078] At room temperature (25℃), 0.98 kg of pseudoboehmite (containing 0.6 kg of Al2O3), 0.26 kg of tartar (0.16 kg dry basis), and 0.44 kg of decationized water were mixed and slurried for 30 minutes. While stirring, 2.01 kg of concentrated phosphoric acid (85% by mass) was added to the slurry at a rate of 0.03 kg phosphoric acid / min / kg alumina source. The temperature was raised to 70℃, and the reaction was carried out at this temperature for 45 minutes to obtain the phosphorus-aluminum inorganic binder DPAL-1. The NMR spectrum is shown below. Figure 1 .

[0079] Depend on Figure 1 It can be seen that, in the 31P NMR spectrum of the aluminum phosphorus binder, the area of ​​the resonance signal peak with a chemical shift of 12±2 ppm is defined as QP0. 2 The peak area of ​​the resonance signal with a chemical shift of 0 ± 2 ppm is defined as QP0. 0 Under the same phosphorus-aluminum ratio, the QP0 of the phosphorus-aluminum binder prepared in Example 1 was... 2 / QP0 0 Compared with the QP0 of the phosphorus aluminum inorganic binder prepared in Comparative Example 1 2 / QP0 0 A higher value indicates a higher degree of polymerization.

[0080] Table 1

[0081]

[0082]

[0083] Examples 1-6 are preparation examples of the additives disclosed herein.

[0084] Example 1

[0085] S1. Take MPZ molecular sieve, add decationized water and slurry for 10 min, then slurry for 120 min to obtain molecular sieve slurry; add kaolin, macroporous alumina material, alumina sol and pseudoboehmite to decationized water and slurry for 20 min, add molecular sieve slurry while stirring, add hydrochloric acid to adjust the pH of the slurry to 3.0, and then continue slurrying for 45 min to obtain the first slurry;

[0086] S2. Add the phosphorus aluminum binder P-1 to the first slurry prepared in step S1, stir for 5 minutes, spray dry the slurry, and calcine the microspheres at 500℃ for 2 hours to obtain the additive CAT-1. The ratio is shown in Table 2.

[0087] Examples 2-6

[0088] The additives were prepared using the same method as in Example 1, except that the raw materials and their amounts were different. The specific proportions are shown in Table 2.

[0089] Comparative Example 1

[0090] MPZ molecular sieve, kaolin, and pseudoboehmite were added, along with decationized water and aluminum sol, and the mixture was stirred for 120 minutes. Hydrochloric acid was added to adjust the pH of the slurry to 3.0, and stirring was continued for another 45 minutes. Then, phosphorus aluminum inorganic binder (DPAL-1) was added, and the mixture was stirred for 5 minutes. The resulting slurry was spray-dried to obtain microspheres. The microspheres were calcined at 500℃ for 1 hour to obtain the additive DCAT-1. The proportions are shown in Table 2.

[0091] Comparative Example 2

[0092] The auxiliary agent DCAT-2 was prepared using the same method as in Example 1, except that the aluminum phosphorus inorganic binder DPAL-1 was used instead of the aluminum phosphorus binder P-1. The material ratio is shown in Table 2.

[0093] Comparative Example 3

[0094] The auxiliary agent DCAT-3 was prepared using the same method as in Example 1, except that no macroporous alumina material was added. The material composition is shown in Table 2.

[0095] Table 2

[0096]

[0097] Test case

[0098] The following examples use a fixed fluidized bed reactor to illustrate the cracking reaction effect of the additives provided in this disclosure.

[0099] The SLA catalytic cracking catalyst, along with 30g of CAT-1~6 and DCAT-1~3, were aged for 17 hours at 800℃ under a 100% steam atmosphere. Different amounts of the aged catalyst were mixed with an industrial balance agent (main properties shown in Table 3), and the catalyst mixtures were loaded into a reactor of a small fixed fluidized bed reactor to catalytically crack the feedstock oil shown in Table 4. Table 5 shows the reaction conditions and results.

[0100] Table 3. Main properties of SLA catalyst for catalytic cracking

[0101] project numerical values Microreactivity, % (mass fraction) 57 rare earth oxides wt% 2.2 Bulk density g / mL 0.8 Copper content, mg / kg <0.05 Iron content, mg / kg 3460 Sodium content, mg / kg 2000 Nickel content, mg / kg 3860 Vanadium content, mg / kg 8340 Pore ​​volume mL / g 0.14 <![CDATA[Specific surface area m 2 / g]]> 103 <20μm, % (volume fraction) 1.04 20-40 μm, % (volume fraction) 12.71 40-80 μm, % (volume fraction) 61.89 80-110 μm, % (volume fraction) 20.67 >110μm, % (volume fraction) 3.69

[0102] Table 4 Evaluation of the properties of the feedstock oil

[0103]

[0104]

[0105] Table 5 Evaluation Results

[0106]

[0107]

[0108]

[0109] As shown in Table 5, compared with the reference catalyst, the additives provided in this disclosure can effectively increase the yield of liquefied petroleum gas and propylene in catalytic cracking, and the propylene concentration in the liquefied petroleum gas is higher, the total liquid yield is higher, and the yield of oil slurry and coke is lower, which significantly improves the heavy oil cracking capacity.

[0110] The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0111] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0112] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A low-carbon olefin additive for heavy oil cracking, said additive comprising MFI molecular sieve, phosphorus aluminum binder, macroporous alumina material, other inorganic binders and clay; Based on the dry weight of the additives, the content of the MFI molecular sieve is 10-75% by weight, the content of the macroporous alumina material is 1-30% by weight, the content of the phosphorus aluminum binder (calculated as oxides) is 3-35% by weight, the content of the other inorganic binders (calculated as oxides) is 1-20% by weight, and the content of the clay is 0-60% by weight. Based on the total weight of the phosphorus aluminum binder, the phosphorus aluminum binder contains 3-15% by weight of Al2O3, 15-40% by weight of P2O5, and 0.1-10% by weight of stabilizer; the P / Al weight ratio of the phosphorus aluminum binder is 1.6-6, the pH value is 0.5-2.5, and the QPO is 0. 2 / QP0 0 The range is 1-5, where, QP0 2 Indicates by 31 P-NMR spectroscopy analysis of the phosphorus aluminum binder yielded a resonance signal peak area with a chemical shift of 12 ± 2 ppm, QP0. 0 The area of ​​the resonance signal peak with a chemical shift of 0±2ppm is indicated; the average particle size of the phosphorus aluminum binder is 10-30nm; the stabilizer is selected from one or more of acetic acid, glycolic acid, oxalic acid, malonic acid, malic acid, tartaric acid, succinic acid, adipic acid, maleic acid, itaconic acid and citric acid. The macroporous alumina material has a bimodal structure, with pores having a diameter of 2-10 nm accounting for 20-40% of the total pore volume, and pores having a diameter of 10-100 nm accounting for 60-80% of the total pore volume.

2. The adjuvant according to claim 1, wherein, The phosphorus-aluminum binder contains 3-12 wt% Al₂O₃, 15-32 wt% P₂O₅, and 0.5-5 wt% stabilizer; the P / Al weight ratio of the phosphorus-aluminum binder is 1.7-5.8, the pH value is 0.5-2.5, and the QPO is [not specified]. 2 / QP0 0 The content of the phosphorus aluminum binder is 1.5-5; the solid content of the phosphorus aluminum binder is 15-50% by weight.

3. The adjuvant according to claim 1, wherein, Based on the dry weight of the additives, the content of the MFI molecular sieve is 15-65% by weight, the content of the macroporous alumina material is 2-20% by weight, the content of the phosphorus aluminum binder (calculated as oxides) is 8-32% by weight, the content of the other inorganic binders (calculated as oxides) is 2-20% by weight, and the content of the clay is 1-25% by weight.

4. The adjuvant according to claim 1, wherein, The other inorganic binder is selected from one or more of boehmite, alumina, aluminum sol, silica-alumina sol, and silica sol. The clay is selected from one or more of kaolin, sepiolite, attapulgite, rettoite, montmorillonite, and diatomite. The MFI molecular sieve is selected from one or more of the following: hydrogen-type MFI molecular sieve, phosphorus-containing MFI molecular sieve, and transition metal-containing MFI molecular sieve.

5. A method for preparing the adjuvant according to any one of claims 1-4, the method comprising: S1. Mix the MFI molecular sieve, the macroporous alumina material, the other inorganic binder, the clay and water to form a slurry, and control the pH value of the slurry to be greater than 2.5 to obtain the first slurry. S2. After mixing the first slurry with the phosphorus aluminum binder, spray drying and calcination are carried out to obtain the additive.

6. The method according to claim 5, wherein, The phosphorus aluminum binder is prepared by a method comprising the following steps: (1) Under the conditions of stirring at a temperature of 50-95℃, aluminum source, water and stabilizer are mixed to obtain an alumina precursor solution with a solid content of 5-40% by weight; (2) The alumina precursor solution is mixed with phosphate at a temperature of 25-70℃ and under stirring conditions to obtain the aluminum phosphate binder.

7. The method according to claim 6, wherein, The aluminum source is selected from one or more of aluminum nitrate, aluminum sulfate, and aluminum chloride; The phosphate is diamine hydrogen phosphate and / or ammonium dihydrogen phosphate; The stabilizer is selected from acetic acid or citric acid.

8. A catalyst comprising an auxiliary agent and an optional main catalyst, wherein the auxiliary agent is the auxiliary agent according to any one of claims 1-7.

9. The application of the catalyst described in claim 8 in the catalytic cracking reaction of heavy feedstock oil.

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