A metal resistant catalytic cracking catalyst and a method of preparation

Abstract

The application discloses an anti-metal catalytic cracking catalyst and a preparation method thereof. The preparation method comprises the following steps: mixing a first raw material with water and beating; adding a rare earth compound and a dispersing agent into the slurry and stirring uniformly; and then performing spray forming, calcining, washing and drying to obtain the catalytic cracking catalyst; the first raw material comprises a boron-phosphorus-aluminum composition, a molecular sieve, clay and a binder; the boron-phosphorus-aluminum composition is a mixture of AlPO4 and B, P and Al, and is subjected to calcining treatment in the preparation process. The obtained catalytic cracking catalyst can resist nickel, vanadium, iron and other metal contaminations at the same time, and has high activity and stability.

Description

Technical Field

[0001] This invention relates to the field of catalytic cracking catalysts, and more specifically to a metal-resistant catalytic cracking catalyst and its preparation method. Background Technology

[0002] Catalytic cracking (FCC) remains a crucial processing method in refineries and still holds a significant position. However, in recent years, with the increasing depletion of petroleum resources and for economic reasons, many refineries have begun processing lower-quality, heavier feedstocks into their catalytic cracking units. These heavy feedstocks often contain metals such as nickel, vanadium, iron, sodium, and calcium. These metals tend to deposit on the catalytic cracking catalyst, causing irreparable damage and consequently affecting the operation of the entire catalytic cracking process.

[0003] Among these metals, nickel, vanadium, and iron have the greatest impact on catalysts. Vanadium forms vanadate under high-temperature steam, which leads to dealumination of the molecular sieve in the catalyst and a decrease in catalyst activity. Nickel's toxicity manifests as a strong catalytic dehydrogenation effect, which reduces the selectivity of catalytic cracking reactions and increases the yield of hydrogen and catalytic coke (coke generated by catalytic cracking reactions at acidic centers). Simultaneously, the presence of nickel exacerbates the destructive effect of vanadium on the molecular sieve. The presence of iron mainly manifests as the formation of a eutectic with low-melting-point components, forming iron nodules on the catalyst surface and blocking the catalyst's pores.

[0004] To reduce the poisoning effect of these metals on catalysts, various processes and technologies have been developed to combat this damage. Among them, catalytic cracking catalysts, as the core of catalytic cracking technology, have their metal resistance enhanced through technological improvements. However, existing technologies rarely mention the preparation of catalytic cracking catalysts that can simultaneously resist metal contamination from nickel, vanadium, iron, and other metals. Summary of the Invention

[0005] The purpose of this invention is to provide a metal-resistant catalytic cracking catalyst and its preparation method. This catalytic cracking catalyst can resist metal contamination such as nickel, vanadium, and iron, and has high activity and stability.

[0006] This invention prepares a boron-phosphorus-aluminum composition, which is added as an additive to a catalytic cracking catalyst to prepare a catalytic cracking catalyst that simultaneously resists contamination by metals such as nickel, vanadium, and iron. The composition is a mixture of AlPO4 and B, P, and Al. The presence of B effectively inhibits nickel metal contamination, and AlPO4 effectively inhibits the dealumination of molecular sieves, thus counteracting the poisoning effect of B on the catalyst.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The first aspect of this invention provides a method for preparing a metal-resistant catalytic cracking catalyst, comprising the following steps:

[0009] The first raw material is mixed with water and slurryed; rare earth compounds and dispersants are added to the slurry and stirred evenly; then it is spray-formed, calcined, washed and dried to obtain the catalytic cracking catalyst.

[0010] The first raw material includes a boron-phosphorus-aluminum composition, molecular sieves, clay, and binder;

[0011] The boron-phosphorus-aluminum composition is a mixture of AlPO4 and B, P, and Al, and is calcined during the preparation process.

[0012] According to the preparation method of the present invention, preferably, the first raw material further includes boehmite.

[0013] According to the preparation method of the present invention, preferably, the boron-phosphorus-aluminum composition is prepared by reacting aluminum compounds, phosphoric acid, and boron compounds and calcining at 400-700°C;

[0014] The boron compound is added at a boron content of 2 wt% to 6 wt% in the total mass of the boron-phosphorus-aluminum composition, preferably 2 wt% to 4 wt%.

[0015] The aluminum compound and phosphoric acid are added in an Al:P molar ratio of (0.5–2.0):1, preferably (0.9–1.5):1.

[0016] According to the preparation method of the present invention, preferably, the boron-phosphorus-aluminum composition is prepared by method one or method two:

[0017] Method 1: Add aluminum compound to water, then add phosphoric acid dropwise; then add boron compound and stir to obtain a sol containing boron, phosphorus and aluminum;

[0018] The sol containing boron, phosphorus, and aluminum is dried and calcined at 400–700°C for 1–4 hours to obtain the boron-phosphorus-aluminum composition.

[0019] Method 2: Add aluminum compound to water, then add phosphoric acid dropwise to obtain a sol containing phosphorus and aluminum; dry the sol containing phosphorus and aluminum to obtain an intermediate product;

[0020] The boron compound was dissolved in water, loaded into the intermediate product by impregnation, dried, and calcined at 400–700°C for 1–4 hours to obtain the boron-phosphorus-aluminum composition.

[0021] In the preparation process of the boron-phosphorus-aluminum composition, the present invention forms a mesoporous structure through calcination, in which boron is fixed in the pores of the composition and does not easily migrate to the surface of the molecular sieve during the preparation of the catalyst, thereby destroying the framework structure of the molecular sieve and enabling the catalyst to maintain relatively high activity stability; the formed mesoporous phosphorus-aluminum structure can effectively reduce iron contamination.

[0022] In both methods one and two, the roasting temperature is preferably 400–700°C, and the roasting time is preferably 1–4 hours. Furthermore, the drying temperature is 80–120°C, and the drying time is 5–24 hours.

[0023] In the preparation of the boron-phosphorus-aluminum composition of the present invention, in methods one and two, after the phosphoric acid is added dropwise, the mixture can be aged for a period of time under stirring, for example, 1 to 5 hours. In method one, it is preferable to continue stirring for 0.5 to 3 hours after adding the boron compound. In the preparation of the boron-phosphorus-aluminum composition, preferably, the aluminum compound is selected from one or more combinations of alumina, boehmite, aluminum nitrate, and aluminum chloride.

[0024] In the preparation of the boron-phosphorus-aluminum composition, preferably, the concentration of phosphoric acid is 20wt% to 85wt%, more preferably 30wt% to 70wt%.

[0025] In the preparation of the boron-phosphorus-aluminum composition, preferably, the boron compound is a soluble boron compound selected from one or more combinations of boron phosphate, boric acid, boron anhydride, ammonium borate, and ammonium fluoroborate.

[0026] In the preparation process of the catalytic cracking catalyst, preferably, the specific preparation process of the catalytic cracking catalyst includes:

[0027] The second raw material is added to water, mixed evenly, aged, and then a binder is added to form a catalyst matrix slurry; the second raw material is a part of the first raw material, including the boron-phosphorus-aluminum composition and clay, or the second raw material includes the boron-phosphorus-aluminum composition, clay, and boehmite;

[0028] The molecular sieve is added to water and sheared before being added to the catalyst matrix slurry. Rare earth compounds and dispersants are added, the mixture is slurried, and then spray-formed, calcined, washed, and dried to obtain the catalytic cracking catalyst.

[0029] More preferably, the aging temperature is 40–90°C, more preferably 75°C, and the aging time is 1–5 hours, more preferably 1 hour.

[0030] In the preparation process of the catalytic cracking catalyst, when the first raw material is mixed with water and slurryed, the solid content of the system is preferably 10wt% to 45wt%. The calcination temperature of the catalytic cracking catalyst is preferably 400 to 800°C, and the calcination time is preferably 0.5 to 3 hours; more preferably, calcination is carried out at 500°C for 1 hour. The drying temperature is preferably 80 to 150°C, and the drying time is preferably 5 to 24 hours. The washing process uses water washing.

[0031] In the preparation process of the catalytic cracking catalyst, preferably, the raw materials corresponding to each component in the obtained catalytic cracking catalyst, based on dry basis oxides, are as follows: the content of the molecular sieve is 20wt% to 50wt%, the content of the boron-phosphorus-aluminum composition is 5wt% to 25wt%, the content of the clay is 18wt% to 45wt%, the content of the pseudoboehmite is 0 to 13wt%, the content of the binder is 8wt% to 15wt%, the content of the rare earth element is 0.5wt% to 10wt%, and the content of the dispersant is 1wt% to 10wt%.

[0032] In the preparation process of the catalytic cracking catalyst, preferably, the molecular sieve is selected from one or a combination of two or more of RDSY molecular sieve, REY molecular sieve, β molecular sieve, and ZSM-5 molecular sieve.

[0033] In the preparation process of the catalytic cracking catalyst, preferably, the clay is selected from one or more combinations of kaolin, malachite, montmorillonite, and attapulgite.

[0034] In the preparation process of the catalytic cracking catalyst, preferably, the binder is selected from one or more combinations of alumina sol, silica sol, or colloidal alumina or silica materials.

[0035] In the preparation process of the catalytic cracking catalyst, preferably, the rare earth compound is a nitrate or carbonate of lanthanum or cerium.

[0036] In the preparation of the catalytic cracking catalyst, preferably, the dispersant is one or a combination of two or more of the following: citric acid, tartaric acid, C2-8 alcohols, polyethylene glycol, cellulose derivatives, polyacrylamide and its derivatives, and glucon. More preferably, the cellulose derivative is selected from sodium hydroxymethyl cellulose, methyl hydroxyethyl cellulose, and hydroxypropyl methyl cellulose; and the C2-8 alcohol is selected from ethanol, ethylene glycol, glycerol, isopropanol, n-propanol, and 1,3-butanediol.

[0037] A second aspect of the present invention provides a metal-resistant catalytic cracking catalyst prepared by any of the above preparation methods.

[0038] According to the metal-resistant catalytic cracking catalyst of the present invention, preferably, the content of the boron-phosphorus-aluminum composition, based on dry basis oxides, is 1 wt% to 30 wt% of the raw materials corresponding to each component of the catalytic cracking catalyst.

[0039] According to the metal-resistant catalytic cracking catalyst of the present invention, preferably, the clay content of each component in the catalytic cracking catalyst, based on dry basis oxides, is 18wt% to 45wt%.

[0040] According to the metal-resistant catalytic cracking catalyst of the present invention, preferably, the content of the pseudoboehmite in the catalytic cracking catalyst, based on dry basis oxides, is 0-13 wt%.

[0041] According to the metal-resistant catalytic cracking catalyst of the present invention, preferably, the content of the binder in the catalytic cracking catalyst, based on dry basis oxides, is 8 wt% to 15 wt% of the raw material.

[0042] According to the metal-resistant catalytic cracking catalyst of the present invention, preferably, the content of the molecular sieve in each component of the catalytic cracking catalyst, based on dry basis oxides, is 20 wt% to 50 wt%.

[0043] According to the metal-resistant catalytic cracking catalyst of the present invention, preferably, the rare earth element content of each component in the catalytic cracking catalyst, based on dry basis oxides, is 0.5wt% to 10wt%.

[0044] According to the metal-resistant catalytic cracking catalyst of the present invention, preferably, the content of the dispersant in the catalytic cracking catalyst, based on dry basis oxides, is 1 wt% to 10 wt% of the raw material.

[0045] This invention incorporates a boron-phosphorus-aluminum composition as an additive in catalyst preparation to obtain a catalytic cracking catalyst resistant to metal contamination. This composition is a mixture of AlPO4 and B, P, and Al. B can effectively combine with nickel, converting it into a more stable compound, reducing the dehydrogenation activity of nickel, and decreasing its poisoning effect on the catalytic cracking catalyst. This effectively reduces hydrogen and coke yields while increasing the yield of high-value-added products. The presence of AlPO4 effectively inhibits the dealumination of molecular sieves, counteracting the poisoning effect of B and V on the catalyst. The relatively large specific surface area of ​​AlPO4 and the loose, porous structure of the catalyst can fix Fe on its surface, effectively preventing Fe flow and reducing Fe poisoning. Rare earth compounds that can fix V are also added to the catalyst, effectively capturing V and thus reducing its poisoning effect on the catalyst.

[0046] During the preparation of the boron-phosphorus-aluminum composition, boron is fixed in the pores of the composition by calcination to form a mesoporous structure. During the preparation of the catalyst, boron does not easily migrate to the surface of the molecular sieve and destroy the framework structure of the molecular sieve, thus enabling the catalyst to maintain relatively high activity stability. Detailed Implementation

[0047] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0048] All numerical specifications in this invention (e.g., temperature, time, concentration, and weight, including ranges for each) are generally approximate values ​​that may be changed (+) or (-) in increments of 0.1 or 1.0. All numerical specifications are to be understood as being preceded by the term "about".

[0049] The raw materials and their properties used in the following examples are as follows:

[0050] Kaolin, silica sol (40 wt% solids), alumina sol (18.0 wt% solids), various molecular sieves, boehmite (dry basis, after deducting loss on ignition, molecular weight 101.96), and hydrochloric acid (30 wt%) are all industrial grade; nickel nitrate, boric acid, boric anhydride, aluminum nitrate, aluminum chloride, ammonium metavanadate, oxalic acid, cerium nitrate, cerium carbonate, lanthanum oxide, glycerol, ethylene glycol, isopropanol, n-propanol, 1,3-butanediol, methyl hydroxyethyl cellulose, hydroxypropyl methyl cellulose, and sodium hydroxymethyl cellulose are analytical grade; phosphoric acid 85 wt%.

[0051] Catalyst microreaction activity evaluation method: The microreaction activity evaluation device developed by Beijing Huier Sanji Green Chemical Technology Co., Ltd. was used for evaluation. The feedstock oil used was the 3 million tons / year catalyst feedstock of Lanzhou Petrochemical Company, and the properties of the feedstock oil are shown in Table 1. The catalyst was aged at 800℃ and 100% steam for 17 hours before evaluation.

[0052] Catalyst reaction performance evaluation methods:

[0053] Before evaluation, the catalyst was contaminated with heavy metals. The method for contaminating the catalyst simulated the nickel and v content in industrial applications: an aqueous solution of nickel nitrate, a solution of ferric naphthenate, and a composite solution of ammonium metavanadate and oxalic acid (10,000 ppm Ni, 3,000 ppm V, 6,000 ppm Fe based on the dry weight of the catalyst) were impregnated into the catalyst using the Mitchell method. After drying at 120°C, the catalyst was calcined at 550°C for 4 hours. Reaction performance was evaluated using an ACE unit. The feedstock used was from the 3 million tons / year catalyst plant of Lanzhou Petrochemical Company, and its properties are shown in Table 1. Before evaluation, the catalyst underwent aging at 800°C with 100% steam for 8 hours.

[0054] Table 1 Properties of Crude Oil

[0055]

[0056] Preparation of boron-phosphorus-aluminum composition:

[0057] Composition 1

[0058] 2129.96g of aluminum nitrate (Al: 10mol) was added to 3L of water under stirring until dissolved. 1152.94g of 85wt% phosphoric acid (P: 10mol) was added dropwise to the dissolved aluminum nitrate to form a homogeneous sol. Then, 85.68g of boric acid (B: 1.4mol) was added, and stirring was continued for 0.5h. The sol was dried in an oven at 80℃ for 24h and calcined at 700℃ for 1h to obtain composition 1.

[0059] Composition 2

[0060] 1019.60g of dry-based boehmite (Al: 20mol) was dispersed in 3L of water under stirring and stirred continuously for 0.5h. 1400.00g of 70wt% phosphoric acid (P: 10mol) was added dropwise under stirring to form a homogeneous sol. Stirring was continued for 1h, followed by the addition of 219.30g of boron anhydride (B: 6.3mol) and stirring for another 1h. The sol was then dried in an oven at 120℃ for 5h and calcined at 500℃ for 2h to obtain composition 2.

[0061] Composition 3

[0062] 1333.40g of aluminum chloride (Al: 10mol) was dissolved in 1L of water under stirring. 6533.33g of 30wt% phosphoric acid (P: 20mol) was added dropwise under stirring to form a homogeneous sol. Stirring was continued for 2h. Then, 653.18g of ammonium borate (B: 10.54mol) was added, and stirring was continued for 1h. The sol was dried in an oven at 90℃ for 10h and calcined at 450℃ for 3h to obtain composition 3.

[0063] Composition 4

[0064] 2129.96g of aluminum nitrate (Al: 10mol) was added to 2L of water under stirring until dissolved. 1633.33g of 40wt% phosphoric acid (P: 6.7mol) was added dropwise to the dissolved aluminum nitrate to form a homogeneous sol. Then, 281.05g of ammonium fluoroborate (B: 2.7mol) was added, and stirring was continued for 0.5h. The sol was dried in an oven at 110℃ for 15h and calcined at 400℃ for 4h to obtain composition 4.

[0065] Composition 5

[0066] 1333.40g of aluminum chloride (Al: 10mol) was dissolved in 1L of water under stirring. 6533.33g of 30wt% phosphoric acid (P: 20mol) was added dropwise under stirring to form a homogeneous sol. Stirring was continued for 2 hours. The sol was then dried in an oven at 120℃ for 10 hours and ground into powder.

[0067] Dissolve 217.28 g of boric acid (B: 3.51 mol) in 500 mL of water, add it to the above powder and soak for 1 h, dry at 120 °C for 5 h, and calcine at 450 °C for 3 h to obtain composition 5.

[0068] Comparative composition 1

[0069] 1019.60 g of dry-based pseudoboehmite (Al: 20 mol) was dispersed in 3 L of water under stirring. The mixture was stirred continuously for 0.5 h. 1960.00 g of 50 wt% phosphoric acid (P: 10 mol) was added dropwise while stirring. The mixture was then stirred and aged for 1 h. After that, 274.11 g of boron anhydride (B: 7.9 mol) was added and the mixture was stirred for 1 h. The sol was then dried in an oven at 100 °C for 12 h to obtain comparative composition 1.

[0070] Comparative composition 2

[0071] 2129.96g of aluminum nitrate (Al: 10mol) was added to 3L of water under stirring until dissolved. Then, 61.83g of boric acid (B: 1mol) was added, and stirring was continued for 0.5h. The mixture was dried in an oven at 80℃ for 24h and calcined at 700℃ for 1h to obtain comparative composition 2.

[0072] Comparative composition 3

[0073] 1019.60g of dry-based pseudoboehmite (Al: 20mol) was dispersed in 3L of water under stirring. The mixture was stirred continuously for 0.5h. 1400.00g of 70wt% phosphoric acid (P: 10mol) was added dropwise under stirring to form a homogeneous sol. The mixture was stirred for another 1h. The sol was then dried in an oven at 120℃ for 5h and calcined at 500℃ for 2h to obtain comparative composition 3.

[0074] The composition and some preparation conditions of the above compositions 1-5 and comparative compositions 1-3 are shown in Table 2.

[0075] Table 2 Composition and preparation conditions of compositions 1-5 and comparative compositions 1-3

[0076]

[0077] Example 1

[0078] This embodiment uses composition 1 to prepare catalytic cracking catalyst S1, including the following steps:

[0079] In a reactor equipped with a water bath heating system, 2.5 L of water, 1335 g of attapulgite, 150 g of pseudoboehmite, and 600 g of Composition 1 were added. Then, 90 g of hydrochloric acid was slowly added and mixed thoroughly. After stirring for 1 hour, the mixture was aged at 75 °C for 1 hour. Then, 1666 g of aluminum sol was added to form a catalyst matrix slurry. 2 L of water and 600 g of β-molecular sieve were added to a slurry tank. After passing the slurry through a high-speed shearing machine for 20 minutes, the slurry was added to the catalyst matrix slurry. 37.83 g of cerium nitrate hexahydrate and 30.0 g of glycerol were added. After slurrying for 1 hour, the mixture was spray-molded. The resulting microspheres were calcined at 500 °C for 1 hour, washed with water, and dried at 150 °C for 5 hours to obtain catalyst S1.

[0080] Example 2

[0081] This embodiment uses composition 2 to prepare catalytic cracking catalyst S2, including the following steps:

[0082] In a reactor equipped with a water bath heating system, 2L of water, 750g of montmorillonite, and 750g of Composition 2 were added and mixed thoroughly. After stirring for 1 hour, the mixture was aged at 75℃ for 1 hour. Then, 1833g of aluminum sol was added to form a catalyst matrix slurry. 1.7L of water, 980g of RDSY and 100g of REY molecular sieve were added to a slurry tank. After passing through a high-speed shearing machine for 20 minutes, the mixture was added to the catalyst matrix slurry. 110.8g of cerium carbonate, 60.0g of methyl hydroxyethyl cellulose, and 60.0g of ethylene glycol were added. After slurrying for 1 hour, the mixture was spray-formed. The resulting microspheres were calcined at 400℃ for 3 hours, washed with water, and dried at 120℃ for 16 hours to obtain catalyst S2.

[0083] Example 3

[0084] This embodiment uses composition 3 to prepare catalytic cracking catalyst S3, including the following steps:

[0085] In a reactor equipped with a water bath heating system, 3.5 L of water, 660 g of halloysite, 150 g of composition 3, and 390 g of pseudoboehmite were added and mixed evenly. 190 g of hydrochloric acid was added dropwise, and the mixture was stirred for 1 hour. After aging at 75 °C for 1 hour, 1333 g of aluminum sol was added to form a catalyst matrix slurry. 4 L of water, 900 g of RDSY + 600 g of ZSM-5 molecular sieve were added to a slurry tank. After passing through a high-speed shearing machine for 20 minutes, the mixture was added to the catalyst matrix slurry. 60.0 g of cerium oxide, 120 g of sodium carboxymethyl cellulose, and 60 g of isopropanol were added. After slurrying for 1 hour, the mixture was spray-formed. The resulting microspheres were calcined at 800 °C for 0.5 hours, washed with water, and dried at 110 °C for 24 hours to obtain catalyst S3.

[0086] Example 4

[0087] This embodiment uses composition 4 to prepare catalytic cracking catalyst S4, including the following steps:

[0088] In a reactor equipped with a water bath heating system, 2.5 L of water, 1020 g of kaolin, 300 g of composition 4, and 180 g of boehmite were added and mixed evenly. 90 g of hydrochloric acid was added dropwise, and the mixture was stirred for 1 hour. After aging at 75 °C for 1 hour, 1333 g of aluminum sol was added to form a catalyst matrix slurry. 3.5 L of water and 1080 g of RDSY molecular sieve were added to a slurry tank. After passing through a high-speed shearing machine for 20 minutes, the mixture was added to the catalyst matrix slurry. 271.0 g of lanthanum chloride, 100 g of n-propanol, and 140.0 g of hydroxypropyl methylcellulose were added. After slurrying for 1 hour, the mixture was spray-molded. The resulting microspheres were calcined at 700 °C for 1 hour, washed with water, and dried at 80 °C for 24 hours to obtain catalyst S4.

[0089] Example 5

[0090] This embodiment uses composition 5 to prepare catalytic cracking catalyst S5, including the following steps:

[0091] In a reactor equipped with a water bath heating system, 3.5 L of water, 540 g of kaolin, 390 g of composition 5, and 240 g of pseudoboehmite were added and mixed evenly. 120 g of hydrochloric acid was added dropwise, and the mixture was stirred for 1 hour. After aging at 75 °C for 1 hour, 1125 g of silica sol was added to form a catalyst matrix slurry. 3.0 L of water and 1080 g of RDSY molecular sieve were added to a slurry tank. After passing through a high-speed shearing machine for 20 minutes, the slurry was added to the catalyst matrix slurry. 598.3 g of lanthanum nitrate and 200.0 g of 1,3-butanediol were added. After slurrying for 1 hour, the mixture was spray-formed. The resulting microspheres were calcined at 500 °C for 1 hour, washed with water, and dried at 100 °C for 20 hours to obtain catalyst S5.

[0092] Example 6

[0093] This embodiment uses composition 2 to prepare catalytic cracking catalyst S6, including the following steps:

[0094] In a reactor equipped with a water bath heating system, 4L of water, 810g of kaolin, 4240g of composition 2, and 270g of boehmite were added and mixed evenly. 130g of hydrochloric acid was added dropwise, and the mixture was stirred for 1 hour. After aging at 75℃ for 1 hour, 900g of silica sol was added to form a catalyst matrix slurry. 4L of water and 1080g of RDSY molecular sieve were added to a slurry tank. After passing through a high-speed shearing machine for 20 minutes, the mixture was added to the catalyst matrix slurry. 337.3g of lanthanum carbonate and 90g of hydroxymethyl cellulose were added. After slurrying for 1 hour, the mixture was spray-molded. The resulting microspheres were calcined at 500℃ for 1 hour, washed with water, and dried at 120℃ for 16 hours to obtain catalyst S6.

[0095] Comparative Example 1

[0096] This comparative example prepares catalytic cracking catalyst D1, in which no boron-phosphorus-aluminum composition is used, and includes the following steps:

[0097] In a reactor equipped with a water bath heating system, 2.5L of water, 1470g of kaolin, and 150g of boehmite were added. Then, 90g of hydrochloric acid was slowly added and mixed thoroughly. After stirring for 1 hour, the mixture was aged at 75℃ for 1 hour. Then, 1666g of aluminum sol was added to form a catalyst matrix slurry. 2L of water and 1080g of RDSY molecular sieve were added to a slurry tank. After passing the sieve through a high-speed shearing machine for 20 minutes, it was added to the catalyst matrix slurry. After slurrying for 1 hour, the mixture was spray-formed. The resulting microspheres were calcined at 500℃ for 1 hour, washed with water, and dried at 130℃ for 16 hours to obtain catalyst D1.

[0098] Comparative Example 2

[0099] This comparative example prepares catalytic cracking catalyst D2, wherein boric acid is used instead of the boron-phosphorus-aluminum composition, and includes the following steps:

[0100] In a reactor equipped with a water bath heating system, 2.5L of water, 1470g of kaolin, 150g of borosilicate, and 422g of boric acid were added, followed by the slow addition of 90g of hydrochloric acid. After stirring for 1 hour, the mixture was aged at 75℃ for 1 hour. Then, 1666g of aluminum sol was added to form a catalyst matrix slurry. 2L of water and 1080g of RDSY molecular sieve were added to a slurry tank. After passing the slurry through a high-speed shearing machine for 20 minutes, the slurry was added to the catalyst matrix slurry. After slurrying for 1 hour, the mixture was spray-formed. The resulting microspheres were calcined at 500℃ for 1 hour, washed with water, and dried at 120℃ for 16 hours to obtain catalyst D2.

[0101] Comparative Example 3

[0102] This comparative example uses comparative composition 1 to prepare catalytic cracking catalyst D3, including the following steps:

[0103] In a reactor equipped with a water bath heating system, 2.5 L of water, 1020 g of kaolin, 300 g of comparative composition 1, and 180 g of boehmite were added and mixed evenly. 90 g of hydrochloric acid was added dropwise, and the mixture was stirred for 1 hour. After aging at 75 °C for 1 hour, 1333 g of aluminum sol was added to form a catalyst matrix slurry. 3.5 L of water and 1080 g of RDSY molecular sieve were added to a slurry tank. After passing through a high-speed shearing machine for 20 minutes, the mixture was added to the catalyst matrix slurry. 271.0 g of lanthanum chloride, 100 g of n-propanol, and 140.0 g of hydroxypropyl methylcellulose were added. After slurrying for 1 hour, the mixture was spray-molded. The resulting microspheres were calcined at 500 °C for 1 hour, washed with water, and dried at 120 °C for 16 hours to obtain catalyst D3.

[0104] Comparative Example 4

[0105] This comparative example prepares catalytic cracking catalyst D4, wherein a sol containing boron, phosphorus, and aluminum is used instead of the boron-phosphorus-aluminum composition of the present invention, and includes the following steps:

[0106] 1155.61g of aluminum chloride was dissolved in 1L of water under stirring. 2426.65g of 70wt% phosphoric acid and 306.8g of boric acid were added dropwise while stirring to form a homogeneous sol. Stirring was continued for 2 hours to obtain sol A.

[0107] In a reactor equipped with a water bath heating system, 1.7 L of water, 540 g of kaolin, and 240 g of boehmite were added and mixed thoroughly. 120 g of hydrochloric acid was added dropwise, and the mixture was stirred for 1 hour. Then, the sol A obtained above was added, and the mixture was aged at 75 °C for 1 hour. Then, 1125 g of silica sol was added to form a catalyst matrix slurry. 3.0 L of water and 1080 g of RDSY molecular sieve were added to a slurry tank. After passing the slurry through a high-speed shearing machine for 20 minutes, the slurry was added to the catalyst matrix slurry. 598.3 g of lanthanum nitrate and 200.0 g of 1,3-butanediol were added, and the mixture was slurried for 1 hour. After spray molding, the resulting microspheres were calcined at 500 °C for 1 hour, washed with water, and dried at 120 °C for 16 hours to obtain catalyst D4.

[0108] Comparative Example 5

[0109] This comparative example uses comparative composition 2 to prepare catalytic cracking catalyst D5, including the following steps:

[0110] In a reactor equipped with a water bath heating system, 2.5 L of water, 1020 g of kaolin, 300 g of comparative composition 2, and 180 g of boehmite were added and mixed evenly. 90 g of hydrochloric acid was added dropwise, and after stirring for 1 hour, the mixture was aged at 75 °C for 1 hour. Then, 1333 g of aluminum sol was added to form a catalyst matrix slurry. 3.5 L of water and 1080 g of RDSY molecular sieve were added to a slurry tank. After passing through a high-speed shearing machine for 20 minutes, the mixture was added to the catalyst matrix slurry. 271.0 g of lanthanum chloride, 100 g of n-propanol, and 140.0 g of hydroxypropyl methylcellulose were added. After slurrying for 1 hour, the mixture was spray-molded, and the resulting microspheres were calcined at 500 °C for 1 hour, washed with water, and dried at 120 °C for 16 hours to obtain catalyst D5.

[0111] Comparative Example 6

[0112] This comparative example uses comparative composition 3 to prepare catalytic cracking catalyst D6, including the following steps:

[0113] In a reactor equipped with a water bath heating system, 2.5 L of water, 1020 g of kaolin, 300 g of comparative composition 3, and 180 g of boehmite were added and mixed evenly. 90 g of hydrochloric acid was added dropwise, and the mixture was stirred for 1 hour. After aging at 75 °C for 1 hour, 1333 g of aluminum sol was added to form a catalyst matrix slurry. 3.5 L of water and 1080 g of RDSY molecular sieve were added to a slurry tank. After passing through a high-speed shearing machine for 20 minutes, the mixture was added to the catalyst matrix slurry. 271.0 g of lanthanum chloride, 100 g of n-propanol, and 140.0 g of hydroxypropyl methylcellulose were added. After slurrying for 1 hour, the mixture was spray-molded. The resulting microspheres were calcined at 500 °C for 1 hour, washed with water, and dried at 120 °C for 16 hours to obtain catalyst D6.

[0114] Comparative Example 7

[0115] This comparative example prepares catalytic cracking catalyst D7, wherein boric acid and phosphoric acid (both accounting for 15 wt% of the catalyst dry basis content) are used instead of the boron-phosphorus-aluminum composition of the present invention, and includes the following steps:

[0116] In a reactor equipped with a water bath heating system, 2.5 L of water, 960 g of kaolin, 180 g of borosilicate, and 422 g of boric acid were added and mixed thoroughly. 90 g of hydrochloric acid was added, and the mixture was stirred for 1 hour. After aging at 75 °C for 1 hour, 1333 g of aluminum sol was added to form a catalyst matrix slurry. 3.5 L of water and 1080 g of RDSY molecular sieve were added to a slurry tank. After passing through a high-speed shearing machine for 20 minutes, the slurry was added to the catalyst matrix slurry. 271.0 g of lanthanum chloride, 100 g of n-propanol, and 140.0 g of hydroxypropyl methylcellulose were added, along with 358 g of 85 wt% phosphoric acid. After slurrying for 1 hour, the mixture was spray-molded, and the resulting microspheres were calcined at 500 °C for 1 hour, washed with water, and dried at 120 °C for 16 hours to obtain catalyst D7.

[0117] The composition of the raw materials corresponding to each component of catalysts S1-S6 and D1-D7 is shown in Table 3 below, the activity data is shown in Table 4 below, and the ACE evaluation results of each catalyst contaminated sample (after 12000ppm nickel contamination) are shown in Table 5.

[0118] Table 3. Composition of the raw materials corresponding to each component in the catalysts obtained in the examples and comparative examples (based on dry oxides).

[0119]

[0120] Note: The dispersant is removed during the calcination process and therefore does not count towards the dry weight of the catalyst.

[0121] Table 4 Catalyst activity (MAT, 800℃×17h)

[0122] Catalyst number S1 S2 S3 S4 S5 S6 D1 D2 D3 D4 D5 D6 D7 Catalyst activity 61 62 63 64 63 65 62 56 58 58 58 63 60

[0123] As shown in Table 4, catalysts S1-S6 in the examples still exhibited relatively high activity after aging in water vapor at 800℃ for 17 hours, while the activity of catalysts D2, D3, D4, D5, and D7 in the comparative examples decreased significantly, indicating that the method of adding boron (B) affects the structure of the molecular sieve. The presence of AlPO4 in the boron-phosphorus-aluminum composition of the present invention can effectively inhibit the dealumination of the molecular sieve and counteract the poisoning effect of B on the catalyst. At the same time, during the preparation of the boron-phosphorus-aluminum composition, a mesoporous structure is formed through calcination, and boron is fixed in the channels of the composition. During the preparation of the catalyst, it is not easy to migrate to the surface of the molecular sieve and destroy the framework structure of the molecular sieve. This allows catalysts S1-S6 to maintain relatively high activity stability even after aging in water vapor at 800℃ for 17 hours. Catalyst D2, which used boric acid instead of the boron-phosphorus-aluminum composition; catalyst D3, which used uncalcined comparative composition 1; catalyst D4, which used a sol containing boron, phosphorus, and aluminum instead of the boron-phosphorus-aluminum composition of the present invention; D5, which used phosphorus-free comparative composition 2 instead of the boron-phosphorus-aluminum composition; and D7, which used phosphoric acid and boric acid instead of the boron-phosphorus-aluminum composition, all showed a significant decrease in activity. Catalyst D1, which did not contain the composition or other B substitutes, served as a blank control; and D6 used boron-free comparative composition 3.

[0124] Table 5. ACE evaluation results of each catalyst contamination sample.

[0125]

[0126] As shown in Table 5, after being contaminated with 10,000 ppm nickel, 3,000 ppm vanadium, and 5,000 ppm iron, the catalyst samples of the examples showed relatively higher conversion rates and lower H2 / CH4 ratios compared to catalyst D1 in the comparative example, indicating that the addition of the boron-phosphorus-aluminum composition of the present invention has certain anti-metal properties. Compared to comparative examples D2, D4, and D7, the examples showed relatively higher conversion rates, indicating that the addition of the boron-phosphorus-aluminum composition can significantly reduce the poisoning effect of B on the molecular sieve; compared to comparative example D3, the examples showed relatively higher conversion rates and better product distribution, indicating that the calcination step of the boron-phosphorus-aluminum composition is crucial; compared to D5 and D6, the examples showed relatively higher conversion rates and better product distribution, indicating that phosphorus and boron elements in the boron-phosphorus-aluminum composition play a key role in resisting contamination by heavy metals such as nickel, vanadium, and iron.

[0127] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method for preparing a metal-resistant catalytic cracking catalyst, wherein, The preparation method includes the following steps: The first raw material is mixed with water and slurried; rare earth compounds and dispersants are added to the slurry and slurried again; then the mixture is spray-formed, calcined, washed and dried to obtain the catalytic cracking catalyst. The first raw material includes a boron-phosphorus-aluminum composition, molecular sieves, clay, and binder; The boron-phosphorus-aluminum composition is a mixture of AlPO4 and B, P, and Al, and is prepared by reacting aluminum compounds, phosphoric acid, and boron compounds and calcining at 400-700°C. The boron compound is added at a boron content of 2 wt% to 6 wt% of the total mass of the boron-phosphorus-aluminum composition. The aluminum compound and phosphoric acid were added at an Al:P molar ratio of (0.5~2.0):1; The boron-phosphorus-aluminum composition is prepared by either method one or method two: Method 1: Add aluminum compound to water, then add phosphoric acid dropwise; then add boron compound and stir to obtain a sol containing boron, phosphorus and aluminum; The sol containing boron, phosphorus, and aluminum is dried and calcined at 400-700°C for 1-4 hours to obtain the boron-phosphorus-aluminum composition. Method 2: Add aluminum compound to water, then add phosphoric acid dropwise to obtain a sol containing phosphorus and aluminum; dry the sol containing phosphorus and aluminum to obtain an intermediate product; The boron compound was dissolved in water, loaded into the intermediate product by impregnation, dried, and calcined at 400-700°C for 1-4 hours to obtain the boron-phosphorus-aluminum composition.

2. The preparation method according to claim 1, wherein, The first raw material also includes boehmite.

3. The preparation method according to claim 1, wherein, The aluminum compound is selected from one or more of alumina, boehmite, aluminum nitrate, and aluminum chloride.

4. The preparation method according to claim 1, wherein, The boron compound is selected from one or more of boron phosphate, boric acid, boron anhydride, ammonium borate, and ammonium fluoroborate.

5. The preparation method according to claim 1, wherein, The specific preparation process of the catalytic cracking catalyst includes: The second raw material is added to water, mixed evenly, aged, and then a binder is added to form a catalyst matrix slurry; the second raw material includes the boron-phosphorus-aluminum composition and clay; The molecular sieve is added to water and sheared before being added to the catalyst matrix slurry. Rare earth compounds and dispersants are added, the mixture is slurried, and then spray-formed, calcined, washed, and dried to obtain the catalytic cracking catalyst.

6. The preparation method according to claim 2, wherein, The specific preparation process of the catalytic cracking catalyst includes: The second raw material is added to water, mixed evenly, aged, and then a binder is added to form a catalyst matrix slurry; the second raw material includes the boron-phosphorus-aluminum composition, clay, and boehmite. The molecular sieve is added to water and sheared before being added to the catalyst matrix slurry. Rare earth compounds and dispersants are added, the mixture is slurried, and then spray-formed, calcined, washed, and dried to obtain the catalytic cracking catalyst.

7. The preparation method according to claim 1, wherein, The calcination temperature of the catalytic cracking catalyst is 400~800℃, and the calcination time is 0.5~3 h.

8. The preparation method according to claim 2, wherein, The components of the obtained catalytic cracking catalyst, based on dry basis oxides, correspond to the following raw materials: the molecular sieve content is 20wt%~50wt%, the boron-phosphorus-aluminum composition content is 5wt%~25wt%, the clay content is 18wt%~45wt%, the pseudoboehmite content is greater than 0 and less than or equal to 13wt%, the binder content is 8wt%~15wt%, the rare earth element content is 0.5wt%~10wt%, and the dispersant content is 1wt%~10wt%.

9. The preparation method according to claim 1, wherein, The molecular sieve is selected from one or more of RDSY molecular sieve, REY molecular sieve, β molecular sieve, and ZSM-5 molecular sieve.

10. The preparation method according to claim 1, wherein, The clay is selected from one or more of the following: kaolin, malachite, montmorillonite, and attapulgite.

11. The preparation method according to claim 1, wherein, The binder is selected from one or more of colloidal alumina or silica materials.

12. The preparation method according to claim 1, wherein, The binder is selected from one or a combination of two of aluminum sol and silica sol.

13. The preparation method according to claim 1, wherein, The rare earth compound is a nitrate or carbonate of lanthanum or cerium.

14. The preparation method according to claim 1, wherein, The dispersant is one or a combination of two or more of the following: citric acid, tartaric acid, C2-C8 alcohols, polyethylene glycol, cellulose derivatives, polyacrylamide and its derivatives, and glucon.

15. The preparation method according to claim 14, wherein, The cellulose derivative is selected from sodium hydroxymethyl cellulose, methyl hydroxyethyl cellulose, and hydroxypropyl methyl cellulose; The C2-C8 alcohols are selected from ethanol, ethylene glycol, glycerol, isopropanol, n-propanol, and 1,3-butanediol.

16. A metal-resistant catalytic cracking catalyst prepared by the preparation method according to any one of claims 1-15.

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