CN103007988A - Cracking assistant for improving low-carbon olefin concentration - Google Patents

Abstract

A cracking aid for increasing the concentration of low-carbon olefins, containing modified MFI molecular sieves, phosphorus-aluminum inorganic binders containing the first clay, and other inorganic binders, with or without the second clay; The phosphorus-aluminum inorganic binder of clay includes an aluminum component, a phosphorus component and the first clay; the modified MFI molecular sieve contains phosphorus and is selected from Fe, Co, Ni, Cu, Mn, Zn, Sn, Bi One or several kinds of transition metals, the infrared spectrum obtained by using collidine as a probe molecule has no absorption peak at 1633cm ^-1 . The additive is used for catalytic cracking, which can increase the yield of catalytic cracking liquefied gas, increase the concentration of low-carbon olefins, especially propylene, in the catalytic cracking liquefied gas, improve the heavy oil conversion ability of the catalyst composition, and improve the selectivity of dry gas and coke.

Description

A cracking aid for increasing the concentration of low-carbon olefins

technical field

The invention relates to a cracking aid for improving low-carbon olefins in catalytic cracking liquefied gas. Furthermore, it relates to a cracking aid for increasing the concentration of propylene in catalytic cracking liquefied gas.

Background technique

Propylene is an important organic chemical raw material. With the increasing demand for propylene derivatives such as polypropylene, the demand for propylene is increasing year by year all over the world. Fluid catalytic cracking is an important method for the production of propylene and other low-carbon olefins. In order to increase the yield of propylene, it is an effective technical approach to use catalysts or additives containing zeolite with MFI structure in the catalytic cracking process.

USP3,758,403 disclosed earlier that adding ZSM-5 zeolite to the catalytic cracking catalyst can increase the octane number of gasoline and increase the yield of C ₃ -C ₄ olefins. For example, after adding ZSM-5 zeolite from 1.5, 2.5, 5 to 10% to a conventional catalyst containing 10% REY, the gasoline octane number increases and the yield of low-carbon olefins increases; Dosage also has the same effect.

USP 5,318,696 proposes a hydrocarbon conversion process based on a catalyst composed of a large-pore zeolite and a zeolite with an MFI structure with a silicon-to-aluminum ratio of less than 30. The process produces high-octane gasoline through an improved catalytic cracking process and increases the production of low-carbon olefins, especially propylene.

USP 5,997,728 discloses a method of using a large amount of shape-selective cracking aids in the catalytic cracking process of heavy feedstocks. The auxiliary agent is composed of 12-40% ZSM-5 zeolite added to the amorphous base, and the system reserve is at least 10%, so that the proportion of ZSM-5 in the catalyst exceeds 3%. This method can greatly increase the low-carbon olefins without additionally increasing the output of aromatics and losing the yield of gasoline.

After the ZSM-5 zeolite is modified with phosphorus-containing compounds, the stability of its cracking activity can be improved, and the dosage of zeolite can be reduced.

CN 1049406C discloses a zeolite containing phosphorus and rare earth and having MFI structure, its anhydrous chemical composition is aRE ₂ O ₃ ·bNa ₂ O ·Al ₂ O ₃ ·cP ₂ O ₅ ·dSiO ₂ , where a=0.01 ~0.25, b=0.005~0.02, c=0.2~1.0, d=35~120. The zeolite has excellent hydrothermal activity stability and good low-carbon olefin selectivity when used for high-temperature conversion of hydrocarbons.

CN 1034223C discloses a cracking catalyst for producing light olefins, which is composed of 0-70% (based on catalyst weight) of clay, 5-99% of inorganic oxide and 1-50% of zeolite. The zeolite is a mixture of 0-25% by weight of REY or high silicon Y-type zeolite and 75-100% by weight of five-membered ring high-silica zeolite containing phosphorus and rare earth. The catalyst has higher hydrothermal activity stability, conversion rate and C ₂ ⁼ ~ C ₄ ⁼ yield than the catalyst with ZSM-5 zeolite as the active component.

USP 5,110,776 discloses the preparation method of ZSM-5 zeolite catalyst modified with phosphorus. The phosphorus modification process is to disperse the zeolite in the phosphorus-containing compound aqueous solution with a pH value of 2-6, and then make a slurry with the matrix, and then spray-dry and form it. The obtained catalyst does not increase dry gas and coke yield while increasing gasoline octane number.

USP6,566,293 discloses a cracking catalyst for phosphorus-containing modified ZSM-5 zeolite. The preparation of the phosphorus-modified ZSM-5 is to disperse the zeolite in an aqueous solution of phosphorus-containing compounds with a pH value above 4.5, make the zeolite load at least 10% by weight of phosphorus (calculated as P ₂ O ₅ ), and then combine with the matrix and other The zeolite components are beaten and spray-dried to shape. The obtained catalyst has a higher yield of light olefins.

A ZSM-5 zeolite modified with phosphorus is disclosed in USP 5,171,921. The zeolite has a silicon-aluminum ratio of 20-60. After being impregnated with a phosphorus-containing compound and treated with steam at 500-700°C, it is relatively free of phosphorus when used for the conversion of C ₃ -C ₂₀ hydrocarbons into C ₂ -C ₅ olefins. Treated ZSM-5 had higher activity.

A method for improving the catalytic activity of small and medium pore zeolites is disclosed in USP 6,080,303. The method is to treat small- and medium-pore zeolites with phosphorus compounds, and then combine the phosphorus-treated zeolites with _AlPO4 gel. This approach can improve the activity and hydrothermal stability of small and medium pore zeolites.

USP 5,472,594 discloses a hydrocarbon conversion process based on a catalyst composed of a large-pore zeolite and a phosphorus-containing MFI structure medium-pore zeolite. The process produces high-octane gasoline through an improved catalytic cracking process, and increases the production of low-carbon olefins, especially C ₄ /C ₅ .

In addition to phosphorus modification of ZSM-5 zeolite, it has also been reported that the introduction of phosphorus compounds into the matrix can improve the selectivity of catalysts or additives to low-carbon olefins.

USP 2002/0003103A1 discloses a catalytic cracking process for increasing the yield of propylene. In addition to sending at least part of the gasoline product into the second riser for re-cracking reaction, the catalyst composition used not only contains large-pore USY zeolite, but also contains medium-pore zeolite such as ZSM-5 and zeolite with cracking performance. Inorganic binder component. The inorganic binder component contains phosphorus, and its P/Al ratio is 0.1-10. The process can greatly increase the production of low-carbon olefins, especially increase the yield of propylene.

USP 2002/0049133A1 discloses a catalyst with high zeolite content and high wear resistance. The catalyst contains 30-85% by weight of ZSM- ₅ zeolite, 6-24% by weight of phosphorus (calculated as _P2O5 ), and less _than 10% by weight of _Al2O3 and the balance of clay and other components , where phosphorus is present in the matrix. The catalyst is used in the catalytic cracking process to increase the yield of light olefins, especially propylene.

The method and application of metal modification of zeolite have the following related reports. For example, USP 5,236,880 discloses catalysts containing MFI or MEL structured zeolites. The zeolite used is modified with Group VIII metals, preferably Ni. After Ni is introduced into the zeolite, it undergoes heat or hydrothermal treatment under strict temperature control, so that Group VIII metals and aluminum are enriched on the surface. When the catalyst is used for alkane conversion, it can increase the gasoline octane number and increase the yield of C ₃ -C ₄ olefins.

CN 1057408A discloses a cracking catalyst containing high silica zeolite, which has high catalytic cracking activity, wherein said high silica zeolite contains 0.01-3.0 wt% phosphorus, 0.01-1.0 wt% iron or 0.01-10 wt% ZSM-5, zeolite beta or mordenite with % aluminum is heated to 350-820°C for 0.1-10 hours ^-1 The volume space velocity is obtained after passing through the aluminum halide aqueous solution, the iron halide aqueous solution or the ammonium phosphate aqueous solution.

CN 1465527A discloses a zeolite with an MFI structure containing phosphorus and transition metals. The anhydrous chemical expression of the zeolite is (0-0.3) Na ₂ O·(0.5-5) Al ₂ O in terms of the mass of oxides ₃ ·(1.3-10)P ₂ O ₅ ·(0.7-15)M ₂ O ₃ ·(70-97)SiO ₂ , wherein M is selected from one of transition metals Fe, Co and Ni. When the zeolite is applied to the catalytic cracking process of petroleum hydrocarbons, although it can increase the yield and selectivity of C ₂ -C ₄ olefins, and has a higher yield of liquefied gas, but the selectivity of dry gas and coke is poor, and the liquefied gas The concentration of propylene in the medium is not high.

CN 1611299A discloses a molecular sieve with MFI structure containing phosphorus and metal components. Its anhydrous chemical expression is calculated by weight of oxides: (0～0.3)Na2O(0.5～5.5)Al ₂ O ₃ (1.3～ 10) P ₂ O ₅ (0.7～15) M1 _x O _y (0.01～5) M2 _m O _n (70～97) SiO2, wherein M1 is selected from one of the transition metals Fe, Co and Ni, and M2 is selected from Any of the metals Zn, Mn, Ga, and Sn.

At present, for the vast majority of catalytic cracking units, under the premise of the same liquefied gas yield, increasing the propylene concentration in the liquefied gas is an important way to improve the economic benefits of the catalytic cracking unit. The propylene additives disclosed in the prior art When used in catalytic cracking process, the concentration of propylene in liquefied gas is low, and when it is added in a large amount, it will weaken the conversion ability of heavy oil.

Contents of the invention

The technical problem to be solved by the present invention is to provide a cracking auxiliary agent for increasing the concentration of propylene in catalytic cracking liquefied gas. The auxiliary agent used in catalytic cracking can increase the concentration of propylene in catalytic cracking liquefied gas and reduce the selectivity of coke and dry gas.

The invention provides a catalytic cracking additive, which contains 10-75% by weight of a modified MFI molecular sieve based on a dry basis, and a phosphorus-aluminum inorganic binder containing a first clay based on the dry weight of the additive. The sum of the aluminum component (calculated as Al ₂ O ₃ ), the phosphorus component (calculated as P ₂ O ₅ ) and the dry weight of the first clay is 3 to 30% by weight of the phosphorus-aluminum inorganic clay containing the first clay. Binder, 3-30% by weight of other inorganic binders based on oxides and 0-60% by weight of the second clay based on dry basis; wherein, the phosphorus-aluminum inorganic binder containing the first clay On the basis of dry weight, the phosphor-aluminum inorganic binder containing the first clay includes 15-40% by weight of aluminum components based on Al ₂ O ₃ and 45-80% by weight of phosphorus components based on P ₂ O ₅ and the first clay of 1 to 40% by weight on a dry basis, and its P/Al weight ratio is 1.0 to 6.0; the anhydrous chemical expression of the modified MFI molecular sieve is expressed by the weight of the oxide as : (0～0.3)Na ₂ O·(0.5～6)Al ₂ O ₃ ·(1.3～10)P ₂ O ₅ ·(0.7～15)M _x O _y ·(70～97)SiO ₂ , x represents The number of atoms of the transition metal M, y represents a number required to satisfy the oxidation state of the transition metal M; the transition metal M is selected from Fe, Co, Ni, Cu, Mn, Zn, Sn, Bi One or more of them; the modified MFI molecular sieve has no absorption peak at 1633 cm ^-1 in the infrared spectrum obtained by using collidine as a probe molecule.

The present invention also provides a preparation method for catalytic cracking additives, comprising mixing modified MFI molecular sieves, phosphorus-aluminum inorganic binders containing the first clay, and other inorganic binders, adding or not adding the second clay, beating, Spray drying; wherein, the phosphor-aluminum compound inorganic binder containing the first clay contains, on a dry basis, 15-40% by weight of an alumina component as Al ₂ O ₃ , and 45% by weight as P ₂ O ₅ ~80% by weight of phosphorus components and 1~40% by weight of clay on a dry basis, the P/Al weight ratio is 1.0~6.0, the pH is 1.0~3.5, and the solid content of the binder is 15~60% by weight; The anhydrous chemical expression of the modified MFI molecular sieve is: (0-0.3) Na ₂ O · (0.5-6) Al ₂ O ₃ · (1.3-10) P ₂ O ₅ ·(0.7～15)M _x O _y ·(70～97)SiO ₂ , x represents the number of atoms of the transition metal M, and y represents a number required to satisfy the oxidation state of the transition metal M; the The transition metal M is preferably selected from one or more of Fe, Co, Ni, Cu, Mn, Zn, Sn, Bi, and the infrared spectrogram obtained by using collidine as a probe molecule for the modified MFI molecular sieve There is no absorption peak at 1633cm ^-1 .

The modified MFI molecular sieve is a molecular _sieve with an MFI structure containing phosphorus and transition metals, and its anhydrous chemical expression is preferably: (0～0.2) _Na2O ·(0.9～5.5) _Al2O3 ·(1.5 ~7)P ₂ O ₅ ·(0.9~10)M _x O _y ·(82~92)SiO ₂ . The phosphorus content on the surface of a molecular sieve is higher than the bulk phosphorus content of the molecular sieve, and the phosphorus distribution D is used to represent the ratio of the surface phosphorus content of the molecular sieve to the bulk phosphorus content of the molecular sieve, and the phosphorus distribution D satisfies D>1, Usually greater than 1～9:1, more preferably (1.05～9):1, wherein D=P( _S) /P _(C) , said P _(S) represents the molecular sieve grain characterized by TEM-EDX method The phosphorus content at one-tenth from the edge to the center, P _(C) represents the phosphorus content at the center of the molecular sieve grain. The molecular sieve with MFI structure is infrared characterized by using collidine as a probe, and its spectrogram has no absorption peak at 1633 cm ⁻¹ . Using collidine as a probe for infrared characterization is an existing method. The process is as follows: the sample is pressed into tablets, placed in the in-situ cell of the infrared spectrometer to seal, vacuumed to 10 ^-3 Pa at 450 ° C, and roasted for 1.5 h, cooled to room temperature; then introduced collidine vapor into the in-situ cell, maintained adsorption equilibrium for 30 min, and took a spectrum. The MFI molecular sieve is preferably one or more of ZMS-5, ZSM-8 and ZSM-11, more preferably ZSM-5 molecular sieve. MFI molecular sieves are also called MFI structure molecular sieves or have MFI structure molecular sieves.

The first clay is one or more of kaolin, sepiolite, attapulgite, retort clay, montmorillonite and diatomite.

The second clay is selected from one or more clays known to those skilled in the art, such as kaolin, metakaolin, sepiolite, attapulgite, montmorillonite, rectorite, diatomite One or more of halloysite, saponite, boronite and hydrotalcite, preferably one of kaolin, metakaolin, diatomite, sepiolite, attapulgite, montmorillonite and rectorite species or a mixture of several species.

The cracking aid provided by the present invention also contains other inorganic binders except the clay-containing phosphorus-aluminum inorganic binder. The other inorganic binders are selected from one or more of the inorganic oxides commonly used in catalytic cracking aids or catalyst substrates or binder components, and can be derived from pseudo-boehmite, aluminum sol, aluminum-phosphorus One or more of glue, silica-alumina sol, and water glass, among which one or more of pseudo-boehmite, alumina sol, and phosphoraluminum glue are preferred.

The catalytic promoter provided by the present invention may also contain 0 to 15% by weight of phosphorus additives based on _P2O5 , and the phosphorus additives are selected from phosphorus compounds, including one of phosphorus _inorganic compounds and organic compounds or Several kinds, which can be easily soluble in water, or poorly soluble in water or insoluble in water, such as phosphorus oxides, phosphoric acid, phosphate, phosphite, hypophosphite, basic phosphoric acid One or more of salt, acid phosphate and phosphorus-containing organic compounds. The preferred phosphorus compound is one or more of phosphoric acid, ammonium phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, aluminum phosphate and aluminum phosphate sol. In the obtained catalyst, the phosphorus additive exists in the form of phosphorus compounds (such as phosphorus oxides, phosphates, phosphites, basic phosphates, and acidic phosphates). When the auxiliary agent contains other phosphorus-containing binders such as phosphorus-aluminum sol other than the phosphorus-aluminum inorganic binder containing the first clay, the phosphorus introduced by the other phosphorus-containing inorganic binders is regarded as phosphorus additive. The total phosphorus content introduced by the phosphorus additive does not exceed 15% by weight. The phosphorus additive can exist in any possible position of the auxiliary agent, such as it can exist in the pore channel of zeolite, the surface of zeolite, it can exist in the matrix material, and it can also exist in the pore channel of zeolite and the surface of zeolite at the same time. and in the matrix material. The phosphorus additive does not include the phosphorus involved in the modified MFI molecular sieve and the phosphorus-aluminum inorganic binder containing the first clay.

The catalytic cracking additive provided by the invention has good wear resistance and catalytic cracking performance, and is used in the heavy oil catalytic cracking reaction process, which can increase the yield of heavy oil catalytic cracking liquefied gas and significantly improve the low-carbon content of catalytic cracking liquefied gas. The concentration of olefins, especially the concentration of propylene, has high selectivity of propylene, low selectivity of coke and dry gas, and can improve the conversion ability of heavy oil, increase the octane number of gasoline, and increase the yield of light oil. Compared with existing additives, it has higher heavy oil conversion activity, higher propylene selectivity and liquefied gas propylene concentration, better coke and dry gas selectivity, and unexpectedly higher liquid recovery. For example, the industrial MLC-500 balancer was reacted at 480°C, the weight hourly space velocity was 16h ^-1 , and the solvent-to-oil ratio was 5, the yield of liquefied gas was 15.31% by weight, the yield of heavy oil was 15.78% by weight, The propylene yield was 4.76% by weight, the propylene concentration in the liquefied gas was 31.09% by weight, the coke selectivity was 9.34% by weight, and the dry gas selectivity was 2.26% by weight. And the modified ZSM-5 molecular sieve containing 50% by weight, 12% by weight of kaolin, 24% by weight of the phosphorus-aluminum inorganic binder containing the first clay, 8% by weight of pseudoboehmite, and 6% by weight of aluminum sol provided by the present invention The auxiliary agent is mixed with the above-mentioned MLC-500 balancing agent at a weight ratio of 10:90, and then reacted under the same conditions. %, the propylene yield was 9.32% by weight, the propylene concentration in the liquefied gas was 41.15% by weight, the coke selectivity was 8.98% by weight, and the dry gas selectivity was 2.17% by weight.

Description of drawings

Fig. 1 is the TEM-EDS spectrogram of the ZSM-5 molecular sieve modified by phosphorus and iron obtained in Example 1 and Comparative Example 1 of the present invention.

Fig. 2 is the collidine adsorption infrared spectrogram of the phosphorus and iron modified ZSM-5 molecular sieve obtained in Example 1 of the present invention and Comparative Example 1, in which line 1 is the spectrogram of the molecular sieve obtained in Comparative Example 1, Line 2 is the infrared spectrum of the phosphorus and iron modified ZSM-5 molecular sieve obtained in Example 1.

Detailed ways

The cracking aid provided by the present invention preferably includes 8-25% by weight of the phosphor-aluminum inorganic binder containing the first clay, 20-60% by weight of modified MFI molecular sieve, 10-45% by weight of clay, 5- 25% by weight of other inorganic binders and 0-10% by weight of phosphorus additives. The content of the phosphorus additive mentioned therein does not include the amount of phosphorus involved in the modified MFI molecular sieve and the phosphorus-aluminum inorganic binder containing the first clay.

Preferably, the first clay in the phosphor-aluminum inorganic binder containing the first clay includes rector's earth, more preferably, the first clay is rector's earth. Based on dry weight, the first clay-containing phosphorus-aluminum compound binder contains 15-35% by weight of aluminum components as Al ₂ O ₃ , and 50-75% by weight of aluminum components as P ₂ O ₅ The phosphorus component and the first clay are 8-35% by weight on a dry basis and do not contain chlorine, the P/Al weight ratio is preferably 2.0-5.0, and the pH is 1.0-3.5.

In the preparation method of the catalytic cracking aid provided by the present invention, the phosphor-aluminum inorganic binder containing the first clay contains 15 to 40% by weight of aluminum groups in terms of Al ₂ O ₃ based on its dry weight. _45-80 % by weight of phosphorus components based on _P2O5 and 1-40% by weight of the first clay based on dry basis, the P/Al weight ratio is 1.0-6.0, and the pH is 1.0-3.5. The solid content of the binder is 15-60% by weight. The preparation method of the first clay-containing phosphorus-aluminum compound inorganic binder comprises:

(1) beating and dispersing the alumina source, the first clay and water into a slurry with a solid content of 8 to 45% by weight; the alumina source is aluminum hydroxide and/or alumina that can be peptized by acid, and The weight ratio of the first clay on a dry basis to _the alumina source calculated as _Al2O3 is 1-40:15-40;

(2) add concentrated phosphoric acid according to the weight ratio of P/Al=1～6 in the slurry that step (1) obtains under stirring; Wherein said P/Al P is the weight of the phosphorus in phosphoric acid in elemental basis, Al is the weight of aluminum calculated as elemental substance in the alumina source;

(3) Reacting the slurry obtained in step (2) at a temperature of 50-99° C. for 15-90 minutes.

Wherein, the consumption of alumina source, concentrated phosphoric acid and the first clay makes the obtained phosphorus-aluminum inorganic binder containing the first clay, based on its dry weight, comprise: 15-40% by weight, preferably 15-35% % by weight Al ₂ O ₃ derived from the alumina source, 45-80% by weight, preferably 50-75% by weight P ₂ O ₅ , 1-40% by weight, preferably 8-35% by weight of the first clay; The P/Al weight ratio is preferably 1.2-6.0, more preferably 2-5. Alumina sources are ρ-alumina, χ-alumina, η-alumina, γ-alumina, κ-alumina, δ-alumina, θ-alumina, gibbsite, pyrenite, Nuo water One or more of diaspore, diaspore, boehmite and pseudo-boehmite, the aluminum component is derived from the alumina source. The first clay is one or more of kaolin, sepiolite, attapulgite, rector's clay, montmorillonite and diatomite, preferably rector's clay. The concentrated phosphoric acid has a concentration of 60-98% by weight, more preferably 75-90% by weight. The feeding rate of phosphoric acid is preferably 0.01-0.10Kg phosphoric acid/min/Kg alumina source, more preferably 0.03-0.07Kg phosphoric acid/min/Kg alumina source.

Due to the introduction of clay, the inorganic binder of the phosphorus-containing aluminum compound not only improves the mass transfer and heat transfer between materials during the preparation process, but also avoids the bonding caused by the exothermic overheating caused by the inhomogeneous local instantaneous violent reaction of the materials. The agent is solidified, the pH value of the binder can be adjusted more flexibly, and a binder with a high solid content can be obtained, and steps such as high-temperature depolymerization and concentration are not required, and the preparation method is simple. The bonding performance of the obtained binder is equivalent to that of the phosphorus-aluminum binder prepared by the method without introducing clay; and the method introduces clay, especially rectorite with a layered structure, which improves the heavy oil conversion ability of the catalyst composition , so that the resulting additives have better selectivity.

The modified MFI molecular sieve (MFI molecular sieve is also called molecular sieve with MFI structure or molecular sieve with MFI structure), contains phosphorus and transition metals, and can be prepared by the following method: the method includes introducing phosphorus in ammonium-exchanged molecular sieves with MFI structure and the transition metal, the phosphorus is introduced in two parts, one part of the phosphorus is introduced after the transition metal is introduced, and the other part of the phosphorus is introduced before the transition metal or simultaneously with the transition metal. The anhydrous chemical expression of the modified MFI molecular sieve obtained is: (0-0.3) Na ₂ O · (0.5-6) Al ₂ O ₃ · (1.3-10) P ₂ O ₅ ·(0.7～15)M _x O _y ·(70～97)SiO ₂ , x represents the number of atoms of the transition metal M, and y represents a number required to satisfy the oxidation state of the transition metal M; the The transition metal M is preferably one or more selected from Fe, Co, Ni, Cu, Mn, Zn, Sn, and Bi.

In the preparation method of the modified MFI molecular sieve, phosphorus and transition metals are introduced into the ammonium-exchanged molecular sieve with MFI structure, wherein the phosphorus is introduced in two parts, one part is introduced after the transition metal is introduced, that is, after all the transition metals are introduced, and the other part The introduction is before the completion of the introduction of the transition metal, that is, it is introduced before or simultaneously with the transition metal. The phosphorus introduced after the transition metal is introduced accounts for 10-90% of the total phosphorus introduced in the molecular sieve, preferably 25-50%. Accounting for 10% to 90% of the total phosphorus introduced into the molecular sieve, preferably 50% to 75%; the atomic molar ratio of the phosphorus introduced after the introduction of the transition metal to the transition metal introduced into the molecular sieve (that is, the molar ratio based on phosphorus atoms and metal atoms) is 0.25 ~10:1, preferably 0.5~2.5:1; the atomic molar ratio of phosphorus introduced before or simultaneously with the transition metal to the transition metal introduced into the molecular sieve is preferably 0.5~4.0:1. Each portion of phosphorus can be introduced in one or more batches.

The ammonium-exchanged MFI structure molecular sieve, which is an ammonium type MFI structure molecular sieve and/or a hydrogen type MFI structure molecular sieve, can be obtained by combining a sodium type molecular sieve with an MFI structure according to molecular sieve:ammonium salt:H ₂ O=1:(0.1 ～1):(5～10) The weight ratio is exchanged at room temperature to 100 ℃ for 0.3～1 hour and then filtered to obtain, wherein the filter cake after filtration can be roasted or not roasted. The sodium oxide content of the ammonium-exchanged MFI structure molecular sieve is preferably not higher than 0.2% by weight. The hydrogen-type MFI molecular sieve can be obtained by roasting the ammonium-type MFI-structure molecular sieve, or by acid-exchanging the sodium-type MFI-structure molecular sieve. The ammonium salt is a water-soluble ammonium salt, which may be a commonly used inorganic ammonium salt, such as one of ammonium chloride, ammonium sulfate or ammonium nitrate or a mixture thereof. The molecular sieve with MFI structure can be ZSM-5, ZSM-8 and ZSM-11, among which ZSM-5 is preferred.

In the preparation _method of the modified MFI molecular sieve, preferably, the sodium molecular sieve with MFI structure is prepared at room temperature ( Usually at 15-30°C) to 100°C for 0.3-1 hour, filter, then impregnate and modify the molecular sieve with a phosphorus-containing compound solution and a solution containing a transition metal compound, wherein the impregnation with the phosphorus-containing compound solution is performed at least twice, And at least once after the impregnation of the transition metal compound; preferably, the impregnation of the phosphorus-containing compound solution is carried out twice, the first time is carried out before the impregnation of the solution containing the transition metal compound or simultaneously with the solution of the transition metal compound; the second time is in the The impregnation of the transition metal compound-containing solution is completed, and the second impregnation is followed by drying and roasting to obtain the product. The phosphorus-containing compound can be selected from one or more of phosphoric acid, ammonium hydrogen phosphate, ammonium dihydrogen phosphate or ammonium phosphate. The transition metal compound is selected from the water-soluble salt of the transition metal, and the water-soluble salt is selected from one of sulfate, nitrate, and chloride salt.

Preferably, the process of impregnating and modifying the molecular sieve with a solution containing a phosphorus compound and a solution containing a transition metal compound is carried out in the following manner:

The ammonium-exchanged filter cake is mixed with the calculated amount of mixed impregnating solution of phosphorus-containing compounds and metal-containing compounds at room temperature to 95°C, dried or roasted at a temperature of 400-800°C after drying, and then mixed with the remaining The phosphorus-containing compound impregnating solution under the temperature is uniformly mixed at room temperature to 95°C, dried, and calcined at a temperature of 400-800°C. The drying is, for example, drying.

In the method for preparing molecular sieves with modified MFI structures containing phosphorus and transition metals provided by the present invention, the calcination process can also be carried out under a water vapor atmosphere.

The modified MFI molecular sieve obtained by the preparation method of the modified MFI molecular sieve has an anhydrous chemical expression based on the weight of the oxide: (0-0.3) Na ₂ O (0.5-6) Al ₂ O ₃ . (1.3-10)P ₂ O ₅ ·(0.7-15)M _x O _y ·(70-97)SiO ₂ , preferably: (0-0.2)Na ₂ O·(0.9-5.5)Al ₂ O ₃ · (1.5～7)P ₂ O ₅ ·(0.9～10)M _x O _y ·(82～92)SiO ₂ , x represents the atomic number of the transition metal M, and y represents the oxidation state satisfying the transition metal M A desired number. The transition metal M is preferably selected from one or more of Fe, Co, Ni, Cu, Mn, Zn, Sn, and Bi. The surface of the obtained molecular sieve with phosphorus and transition metal MFI structure is rich in phosphorus, its surface phosphorus content is greater than its bulk phase phosphorus content, and its phosphorus distribution D is greater than 1, preferably 1.05-9, more preferably 1:1.15-9; It uses collidine as a probe molecule for infrared characterization, and there is no L-acid characteristic absorption peak at 1633cm ^-1 in the infrared spectrum, indicating that there is basically no L-acid on the outer surface, and the metal center on the outer surface is covered by phosphorus.

In the preparation method of catalytic cracking additive provided by the present invention, the modified MFI molecular sieve, the phosphorus-aluminum inorganic binder containing the first clay, and other inorganic binders are mixed and beaten, and the order of addition has no special requirements, for example The phosphor-aluminum inorganic binder containing the first clay, other inorganic binders (when not containing other inorganic binders, can omit the relevant addition steps), modified MFI molecular sieves, and the second clay mixed (when When the second clay is not included, the relevant addition steps can be omitted) beating,

The preparation method of the catalytic cracking aid provided by the present invention also includes the step of spray drying the slurry obtained from the beating. The method of spray drying is well known to those skilled in the art, and there is no special requirement in the present invention.

When the additive contains a phosphorus additive, the introduction of the phosphorus additive is one of the following methods or a combination of several methods, but not limited to these methods:

1. Add phosphorus compound to the slurry before spray drying;

2. Introduced into the auxiliary by other inorganic binders. For example, when the inorganic oxide binder contains phosphorus-aluminum sol, phosphorus is brought into the auxiliary after roasting, and the phosphorus-aluminum sol can also act as a matrix material and adhesive. The effect of caking agent, this part phosphorus also belongs to the phosphorus additive of the present invention;

3. After the auxiliary agent is spray-dried and shaped, it is impregnated or chemically adsorbed phosphorus compound, introduced through solid-liquid separation (if necessary), drying and roasting, wherein the drying temperature is from room temperature to 400°C, preferably 100-300°C , the firing temperature is 400-700°C, preferably 450-650°C, and the firing time is 0.5-100 hours, preferably 0.5-10 hours.

The cracking aid provided by the invention is suitable for catalytic cracking of hydrocarbon oil. When used in the catalytic cracking process, it can be added to the catalytic cracking reactor alone or mixed with the cracking catalyst. Generally, the auxiliary agent provided by the present invention accounts for 1 to 30% by weight of the total amount of the FCC catalyst and the catalyst mixture provided by the present invention, preferably 3 to 20% by weight, and the hydrocarbon oil is selected from various petroleum fractions, such as crude oil , Atmospheric residual oil, vacuum residual oil, atmospheric gas oil, vacuum gas oil, straight-run gas oil, one or more of propane light/heavy deoiling, coking gas oil and coal liquefaction products. The hydrocarbon oil may contain heavy metal impurities such as nickel and vanadium and impurities such as sulfur and nitrogen. For example, the content of sulfur can be as high as 3.0% by weight, the content of nitrogen can be as high as 2.0% by weight, and the content of metal impurities such as vanadium and nickel can be as high as 3000ppm.

The cracking aid provided by the invention is used in the catalytic cracking process, and the hydrocarbon oil cracking conditions are conventional catalytic cracking conditions. Generally speaking, the hydrocarbon oil cracking conditions include a reaction temperature of 400-600°C, preferably 450-550°C, a weight hourly space velocity of 10-120 hours ^-1 , preferably 10-80 hours ^-1 , and an agent-to-oil ratio (by weight ratio) is 1-20, preferably 3-15. The cracking aid provided by the invention can be used in various existing catalytic cracking reactors, such as fixed bed reactors, fluidized bed reactors, riser reactors, and multi-reaction zone reactors.

The following examples will further illustrate the present invention, but do not limit the present invention thereby.

Some raw materials used are as follows: Pseudoboehmite is an industrial product produced by Shandong Aluminum Company, with a solid content of 60% by weight; aluminum sol is an industrial product produced by Sinopec Catalyst Qilu Branch, with _{an Al2O3} content of 21.5% by weight; The glass is an industrial product produced by Sinopec Catalyst Qilu Branch, with a SiO ₂ content of 28.9% by weight and a Na ₂ O content of 8.9% by weight; kaolin is a special kaolin for cracking catalyst produced by Suzhou Kaolin Company, with a solid content of 78% by weight; retort clay: Hubei Zhongxiang Mingliu Rectorite Development Co., Ltd., quartz sand <3.5% by weight, Al ₂ O ₃ 39.0% by weight, Fe ₂ O ₃ 2.0% by weight, Na ₂ O 0.03% by weight, solid content 77% by weight; ZRP-5 zeolite is An industrial product of conventional MFI structure zeolite produced by Sinopec Catalyst Qilu Branch, with P ₂ O ₅ 2.5% by weight, crystallinity 85% by weight, and silicon-aluminum ratio (SiO ₂ /Al ₂ O ₃ , molar ratio, the same below) 50. SB aluminum hydroxide powder: produced by Condex, Germany, with an Al ₂ O ₃ content of 75% by weight; γ-alumina powder: produced by Condex, Germany, with an Al ₂ O ₃ content of 95% by weight. Hydrochloric acid: chemically pure, concentration 36-38% by weight, produced by Beijing Chemical Factory.

Examples 1-5 prepared molecular sieves used in the present invention; Comparative Examples 1-5 prepared comparative molecular sieves. The chemical composition of molecular sieves is shown in Table 1.

Example 1

Dissolve 5kg NH ₄ Cl in 100kg water, add 10kg (dry basis) crystallization product ZSM-5 molecular sieve (produced by Sinopec Catalyst Qilu Branch, synthesized by amine method, SiO ₂ /Al ₂ O ₃ =50) to this solution , exchanged at 90°C for 0.5h, filtered to obtain a filter cake; 0.56kg H ₃ PO ₄ (concentration 85% by weight) and 0.81kg Fe(NO ₃ ) ₃ ·9H ₂ O were dissolved in 9kg water, and the soaking solution was mixed with the filtered The cake was mixed and impregnated, dried, and roasted at 550°C for 2 hours to obtain the sample after the first impregnation; 0.34kg H ₃ PO ₄ (concentration 85% by weight) was dissolved in 9kg of water, and the impregnation solution was mixed with the above-mentioned first impregnation Afterwards, the samples were mixed and impregnated, dried, and calcined at 550°C for 2 hours to obtain the modified MFI molecular sieve of the present invention, denoted as A ₁ . The chemical composition (mass) of elemental analysis is 0.08Na ₂ O·3.0Al ₂ O ₃ ·5.4P ₂ O ₅ ·1.5Fe ₂ O ₃ ·89.3SiO ₂ . Phosphorus introduced a second time accounted for 38%. The distribution D of phosphorus is 1.48.

Comparative example 1

According to the method of CN1425567A, the molecular sieve containing phosphorus and transition metal and having MFI structure was prepared.

Dissolve 5kg NH ₄ Cl in 100kg water, add 10kg (dry basis) crystallization product ZSM-5 molecular sieve (produced by Sinopec Catalyst Qilu Branch, synthesized by amine method, SiO ₂ /Al ₂ O ₃ =50) to this solution , exchanged at 90°C for 0.5h, filtered to obtain a filter cake; 0.9kg H ₃ PO ₄ (concentration 85% by weight) and 0.81kg Fe(NO ₃ ) ₃ ·9H ₂ O were dissolved in 90g water, mixed with the filter cake, soaked and dried dry; the resulting sample was calcined at 550°C for 2 hours to obtain a comparative molecular sieve, denoted as B ₁ . The elemental analysis chemical composition is 0.08Na ₂ O·3.0Al ₂ O ₃ ·5.4P ₂ O ₅ ·1.5Fe ₂ O ₃ ·89.3SiO ₂ . The distribution D of phosphorus is: 1.48

Example 2

Dissolve 5kg of NH ₄ Cl in 100kg of water, add 10kg (dry basis) of crystallization product ZSM-5 molecular sieve (produced by Sinopec Catalyst Qilu Branch of Sinopec, synthesized by amine method, SiO ₂ /Al ₂ O ₃ =50 ), exchanged at 90°C for 0.5h, and filtered to obtain a filter cake; 0.61kg H ₃ PO ₄ (concentration 85% by weight) and 3kg Co(NO ₃ ) ₂ ·6H ₂ O were dissolved in 9kg water to obtain an impregnating solution. The impregnating liquid and the filter cake were mixed and impregnated, dried, and roasted at 550°C for 2 hours to obtain a sample; 0.32kgH ₃ PO ₄ (concentration 85% by weight) was dissolved in 9kg of water to obtain an impregnating liquid, and this impregnating liquid was mixed with the above sample for impregnation, After drying and calcination at 550°C for 2 hours, the modified MFI molecular sieve of the present invention is obtained, denoted as A ₂ . The elemental analysis chemical composition is 0.11Na ₂ O·2.8Al ₂ O ₃ ·5.5P ₂ O ₅ ·8.6Co ₂ O ₃ ·83SiO ₂ , the phosphorus introduced for the second time accounts for 34%, and the distribution D of phosphorus is 1.32.

Comparative example 2

Dissolve 5kg NH ₄ Cl in 100kg water, add 10kg (dry basis) crystallization product ZSM-5 molecular sieve (produced by Sinopec Catalyst Qilu Branch, synthesized by amine method, SiO ₂ /Al ₂ O ₃ =50) to this solution , exchanged at 90°C for 0.5h, filtered to obtain a filter cake; 0.93kgH ₃ PO ₄ (concentration 85% by weight) and 3kgCo(NO ₃ ) ₂ ·6H ₂ O were dissolved in 9kg of water, and the impregnated solution was evenly mixed with the filter cake Mixed, impregnated, and dried; the obtained sample was calcined at 550°C for 2 hours to obtain a comparative molecular sieve, denoted as B ₂ . The elemental analysis chemical composition is 0.11Na ₂ O·2.8Al ₂ O ₃ ·5.5P ₂ O ₅ ·8.6Co ₂ O ₃ ·83SiO ₂ .

Example 3

Dissolve 5kg NH ₄ Cl in 100kg water, add 10kg (dry basis) crystallization product ZSM-5 molecular sieve (produced by Sinopec Catalyst Qilu Branch, synthesized by amine method, SiO ₂ /Al ₂ O ₃ =50) to this solution , exchanged at 90°C for 0.5h, filtered to obtain a filter cake; 0.15kg H ₃ PO ₄ (concentration 85% by weight) and 0.38kg Ni(NO ₃ ) ₂ ·6H ₂ O were dissolved in 9kg water, and the impregnated solution was mixed with the filtered The cake was uniformly mixed and dipped, dried, and roasted at 550°C for 2 hours to obtain the first impregnation sample; 0.1kg H ₃ PO ₄ (concentration 85% by weight) was dissolved in 9 kg of water, and the impregnation solution was mixed with the above first impregnation The samples were mixed and impregnated, dried, and calcined at 550°C for 2 hours to obtain the modified MFI molecular sieve of the present invention, denoted as A ₃ . The elemental analysis chemical composition is 0.1Na ₂ O·3.2Al ₂ O ₃ ·1.5P ₂ O ₅ ·1.0NiO·94.2SiO ₂ , the phosphorus introduced for the second time accounts for 40%, and the distribution D of phosphorus is 1.15.

Comparative example 3

Dissolve 5kg NH ₄ Cl in 100kg water, add 10kg (dry basis) crystallization product ZSM-5 molecular sieve (produced by Qilu Catalyst Branch Company, synthesized by amine method, SiO ₂ /Al ₂ O ₃ =50) to this solution, After exchanging at 90°C for 0.5h, filter the filter cake; add 0.25kg H ₃ PO ₄ (concentration 85% by weight) and 0.38kg Ni(NO ₃ ) ₂ ·6H ₂ O to dissolve in 9kg water, mix the impregnating solution with the filter cake Mixing, impregnation and drying; the obtained sample was calcined at 550°C for 2 hours to obtain a modified MFI molecular sieve, which is denoted as B ₃ . The elemental analysis chemical composition is 0.1Na ₂ O·3.2Al ₂ O ₃ ·1.5P ₂ O ₅ ·1.0NiO·94.2SiO ₂ .

Example 4

Dissolve 5kg NH ₄ Cl in 100kg water, add 10kg (dry basis) crystallization product ZSM-5 molecular sieve (produced by Sinopec Catalyst Qilu Branch, synthesized by amine method, SiO ₂ /Al ₂ O ₃ =50) to this solution After exchanging at 90°C for 0.5h, filter cake was obtained by filtration; 0.39kg H ₃ PO ₄ (concentration 85% by weight) and 0.332KgMn(NO ₃ ) ₂ were dissolved in 9kg water, and the soaking solution was mixed with filter cake for impregnation, Dry and roast at 550°C for 2 hours to obtain sample Y4; dissolve 0.16kg H ₃ PO ₄ (concentration 85% by weight) in 9kg of water, mix this impregnating solution with the above sample Y4, immerse, dry, and roast at 550°C for 2 hours. That is to obtain the molecular sieve of the present invention, denoted as A ₄ . The elemental analysis chemical composition is 0.12Na ₂ O·3.0Al ₂ O ₃ ·3.5P ₂ O ₅ ·6.0Mn ₂ O ₃ ·87.4SiO ₂ . Phosphorus introduced for the second time accounted for 29%. The distribution D of phosphorus is 3.48.

Comparative example 4

Dissolve 5kg of NH ₄ Cl in 100kg of water, add 10kg (dry basis) of crystallization product ZSM-5 molecular sieve (produced by Sinopec Catalyst Qilu Branch, synthesized by amine method, SiO ₂ /Al ₂ O ₃ =50) to this solution, After exchanging at 90°C for 0.5h, filter the filter cake; dissolve 0.55kg H ₃ PO ₄ (concentration 85% by weight) and 0.332kg Mn(NO ₃ ) ₂ in 9kg water, mix the impregnating solution with the filter cake, impregnate and dry Dry; the resulting sample was calcined at 550°C for 2 hours to obtain a modified MFI molecular sieve, denoted as B ₄ . The elemental analysis chemical composition is 0.12Na ₂ O·3.0Al ₂ O ₃ ·3.5P ₂ O ₅ ·6.0Mn ₂ O ₃ ·87.4SiO ₂ .

Example 5

Dissolve 5kg NH ₄ Cl in 100kg water, add 10kg (dry basis) crystallization product ZSM-5 molecular sieve (produced by Sinopec Catalyst Qilu Branch, synthesized by amine method, SiO ₂ /Al ₂ O ₃ =50) to this solution , exchanged at 90°C for 0.5h, and filtered to obtain a filter cake; 0.31kg H ₃ PO ₄ (concentration 85% by weight), 0.82kg Fe(NO ₃ ) ₃ ·9H ₂ O and 0.22kgBi(NO ₃ ) ₃ ·5H ₂ O was dissolved in 9kg of water, and the impregnating liquid was mixed with _the filter cake for impregnation, dried, and roasted at ₅₅₀ °C for 2 hours to obtain the first impregnated sample; This impregnating solution was mixed with the above first impregnated sample, impregnated, dried, and calcined at 550°C for 2 hours to obtain the phosphorus and transition metal modified MFI molecular sieve of the present invention, denoted as A ₅ . The elemental analysis chemical composition is 0.1Na ₂ O·3.1Al ₂ O ₃ ·3.1P ₂ O ₅ ·1.6Fe ₂ O ₃ ·1.0Bi ₂ O ₃ ·91.1SiO ₂ . It can also be expressed as 0.1Na ₂ O 3.1Al ₂ O ₃ 3.1P ₂ O ₅ 2.6M ₂ O ₃ 91.1SiO ₂ , where the calculated atomic weight of M is 82.9. Phosphorus introduced for the second time accounted for 40%. The distribution D of phosphorus is 2.43.

Comparative example 5

Dissolve 5kg NH ₄ Cl in 100kg water, add 10kg (dry basis) crystallization product ZSM-5 molecular sieve (produced by Qilu Catalyst Branch Company, synthesized by amine method, SiO ₂ /Al ₂ O ₃ =50) to this solution, After exchanging at 90°C for 0.5h, filter the filter cake; add 0.52kg H ₃ PO ₄ (concentration 85% by weight) and 0.82kg Fe(NO ₃ ) ₃ 9H ₂ O, 0.22kg Bi(NO ₃ ) ₃ 5H ₂ Dissolve O in 9kg of water, mix the impregnation solution with the filter cake, impregnate and dry; the obtained sample is roasted at 550°C for 2 hours to obtain a modified molecular sieve, which is denoted as B ₅ . The elemental analysis chemical composition is 0.1Na ₂ O·3.1Al ₂ O ₃ ·3.1P ₂ O ₅ ·1.6Fe ₂ O ₃ ·1.0Bi ₂ O ₃ ·91.1SiO ₂ . It can also be expressed as 0.1Na ₂ O 3.1Al ₂ O ₃ 3.1P ₂ O ₅ 2.6M ₂ O ₃ 91.1SiO ₂ , where the calculated atomic weight of M is 82.9.

Table 1

Example 6

The samples prepared in Examples 1-5 and Comparative Example 1 were characterized by TEM-EDS for the distribution of Fe ₂ O ₃ and P ₂ O ₅ . The TEM-EDS results of Example 1 and Comparative Example 1 are shown in FIG. 1 .

Table 1 shows the infrared characterization results of the molecular sieves obtained in Examples 1-5 and Comparative Examples 1-5. The infrared spectrograms of Example 1 and Comparative Example 1 are shown in Figure 2.

It can be seen from Figure 1 that in the sample prepared in Comparative Example 1, Fe ₂ O ₃ and P ₂ O ₅ are uniformly distributed in the bulk phase and on the surface, and in the sample prepared in Example 1, Fe ₂ O ₃ in the bulk phase and the surface is uniformly distributed, while P ₂ O ₅ is enriched on the surface.

Examples 7-10 prepare the phosphorus-aluminum inorganic binder containing clay used in the present invention, and the formula and composition are shown in Table 2.

Example 7

This example prepares the clay-containing phosphorus-aluminum inorganic binder of the present invention.

0.74 kg of pseudoboehmite (containing 0.45 kg of Al ₂ O ₃ ), 0.39 kg of rectorite (0.30 kg on a dry basis) and 1.6 kg of decationized water were beaten for 30 minutes, and 2.03 kg of concentrated phosphoric acid ( Mass concentration 85%), phosphoric acid addition speed is 0.04Kg phosphoric acid/minute/Kg alumina source, be warmed up to 70 ℃, then react at this temperature for 45 minutes, promptly make the phosphorus-aluminum inorganic binder containing clay. The material ratio is shown in Table 2.

Embodiment 8～10

Examples 8-10 prepare the clay-containing phosphorus-aluminum inorganic binder of the present invention, and refer to Example 7 for its preparation method. The material ratio is shown in Table 2.

Comparative example 6

This comparative example prepares the phosphoraluminum glue (phosphoraluminum sol) used in the comparative example of the present invention.

Phosphorus-aluminum glue preparation: 0.66 kilograms of pseudoboehmite (0.44 kilograms on a dry basis) and 1.75 kilograms of decationized water were beaten for 30 minutes, and 2.6 kilograms of concentrated phosphoric acid (chemically pure, containing 85% by weight of phosphoric acid) were added to the slurry under stirring, Raise the temperature to 70° C., and then react at this temperature for 45 minutes to obtain phosphor-aluminum glue (phosphor-aluminum binder). The material ratio is shown in Table 2.

Examples 11-18 prepare the auxiliary agents provided by the present invention. The additive formula is shown in Table 3, and the preparation process is described as follows:

Example 11

Take molecular sieve A ₁ , kaolin and pseudo-boehmite, add decationized water and aluminum sol and beat for 120 minutes to obtain a slurry with a solid content of 30% by weight, add hydrochloric acid to adjust the pH value of the slurry to 3.0, then continue to beat for 45 minutes, and then Add the clay-containing phosphorus-aluminum inorganic binder (Binder2) prepared in Example 8, stir for 30 minutes, spray dry the resulting slurry to obtain microspheres, and roast the microspheres at 500°C for 1 hour to obtain ZJ ₁ , and its ratio is shown in Table 3.

Table 2

Example 12

Take molecular sieve A ₁ , kaolin and pseudo-boehmite, add decationized water and aluminum sol and beat for 120 minutes to obtain a slurry with a solid content of 30% by weight, add hydrochloric acid to adjust the pH value of the slurry to 3.0, continue beating for 45 minutes, and then Add the clay-containing phosphorus-aluminum inorganic binder (Binder1) prepared in Example 7. The obtained slurry was spray-dried under the conditions of a drying gas inlet temperature of 500° C. and an exhaust gas temperature of 180° C. to obtain microspheres with an average particle diameter of 65 μm. The microspheres were fired at 500°C for 1 hour.

Take the obtained microsphere product, add diammonium hydrogen phosphate aqueous solution, heat up to 60°C under stirring, react at this temperature for 20 minutes, vacuum filter the slurry, dry it, and then roast it at 500°C for 2 hours to obtain the auxiliary agent ZJ ₂ . The ratio of additives is shown in Table 3.

Example 13

Take molecular sieve _A1 and pseudo-boehmite, kaolin, diatomaceous earth, add decationized water and water glass and beat for 120 minutes to obtain a slurry with a solid content of 35% by weight, add hydrochloric acid to make the pH value of the slurry 3, and then beat for 45 minutes , add the clay-containing phosphorus-aluminum inorganic binder (Binder 3) prepared in Example 9 to the mixed slurry, stir for 30 minutes, spray-dry the obtained slurry to obtain microspheres, and roast the microspheres at 500° C. for 1 hour , to obtain the auxiliary agent ZJ ₃ , and its proportion is shown in Table 3.

Example 14

Take molecular sieve _A1 , pseudoboehmite and kaolin, add decationized water and aluminum sol and beat for 120 minutes to obtain a slurry with a solid content of 38% by weight, add hydrochloric acid to make the pH value of the slurry 3.0, beat for 45 minutes, and then mix Add the clay-containing phosphorus-aluminum inorganic binder (Binder 4) prepared in Example 10 and the phosphorus-aluminum binder provided in Comparative Example 6 into the slurry, and stir for 30 minutes. Spray-dry the obtained slurry under the condition of dry air inlet temperature of 500°C and exhaust gas temperature of 180°C to obtain microspheres with an average particle diameter of 65 microns, and roast the microspheres at 500°C for 1 hour to obtain additive ZJ ₄ , and its ratio is shown in Table 3.

Example 15

Take molecular sieve _A2 , pseudo-boehmite and kaolin, add decationized water and beat for 120 minutes to obtain a slurry with a solid content of 30% by weight, add hydrochloric acid to adjust the pH value of the slurry to 3, then beat for 45 minutes, and then add The clay-containing phosphorus-aluminum binder (Binder 1) prepared in Example 7 was stirred for 30 minutes. The resulting slurry was spray dried to obtain microspheres. The microspheres were calcined at 500°C for 1 hour to obtain the additive ZJ ₅ , and the ratio of the additives is shown in Table 3.

Example 16

Take molecular sieve _A3 and kaolin, add decationized water and aluminum sol and beat for 120 minutes to obtain a slurry with a solid content of 30% by weight, add hydrochloric acid to adjust the pH value of the slurry to 3, continue beating for 45 minutes, and then add the slurry prepared in Example 8 containing Phosphorous aluminum inorganic binder of clay (Binder 2) and diammonium hydrogen phosphate solid are stirred evenly, then the obtained slurry is spray-dried to obtain microspheres, and the microspheres are calcined at 400°C for 1 hour to obtain additive ZJ ₆ . The ratio is shown in Table 3.

Example 17

Take molecular sieve _A4 , pseudo-boehmite and kaolin, add decationized water and aluminum sol for beating for 120 minutes to obtain a slurry with a solid content of 30% by weight, adjust the pH value of the slurry to 3.0 with hydrochloric acid, then continue beating for 45 minutes, add The clay-containing phosphorus-aluminum inorganic binder (Binder 3) prepared in Example 9 was stirred for 30 minutes, and the obtained slurry was spray-dried to obtain microspheres, which were calcined at 500° C. for 1 hour to obtain the auxiliary agent ZJ ₇ . The ratio of additives is shown in Table 3.

Example 18

Take molecular sieve _A5 , kaolin clay and pseudo-boehmite, add decationized water and aluminum sol and beat for 120 minutes to obtain a slurry with a solid content of 30% by weight, add hydrochloric acid to make the pH of the slurry 3, continue beating for 30 minutes, add The clay-containing phosphorus-aluminum inorganic binder (Binder 3) prepared in Example 9 was beaten again for 30 minutes, and then the obtained slurry was spray-dried to obtain, and the microspheres were roasted at 500° C. for 1 hour to obtain the auxiliary agent ZJ ₈ . The ratio of additives is shown in Table 3.

Comparative example 7

Take _A1 , kaolin and pseudo-boehmite, add decationized water and aluminum sol and beat for 120 minutes to obtain a slurry with a solid content of 30% by weight, and add hydrochloric acid with a concentration of 36% by weight under stirring to make the pH of the slurry 3.0 , and then beating for 45 minutes, spray-dried the resulting slurry to obtain microspheres with an average particle diameter of 65 microns, and calcined the microspheres at 500°C for 1 hour to prepare the reference additive DB ₁ . The ratio of reference additives is shown in Table 4.

Comparative example 8

Take _A1 , kaolin and pseudo-boehmite, add decationized water and aluminum sol and beat for 120 minutes to obtain a slurry with a solid content of 30% by weight, add hydrochloric acid under stirring, control the pH value of the slurry to 3.0 by the amount of hydrochloric acid, and continue the mixture After beating for 45 minutes, add the phosphorus-aluminum binder prepared in Comparative Example 6, and stir for another 30 minutes. The obtained slurry is spray-dried at an inlet temperature of 500° C. and an exhaust gas temperature of 180° C. to obtain an average particle diameter of 65 micron microspheres. The microspheres were calcined at 500°C for 1 hour to prepare the reference additive DB ₂ . The ratio of reference additives is shown in Table 4.

Comparative example 9

The additive was prepared according to the method of Example 11, except that molecular sieve B ₁ was used to replace A ₁ to obtain reference additive DB ₃ . The ratio of reference additives is shown in Table 4.

Comparative example 10

The auxiliary agent was prepared according to the method of Comparative Example 7, except that molecular sieve ZRP-5 was used to replace A ₁ to obtain the reference auxiliary agent DB ₄ . The ratio of reference additives is shown in Table 4.

Comparative example 11

The auxiliary agent was prepared according to the method of Example 15, except that molecular sieve B ₂ was used instead of A ₂ to obtain reference auxiliary agent DB ₅ . The ratio of reference additives is shown in Table 4.

Comparative example 12

Take molecular sieve B ₃ and kaolin, add decationized water and aluminum sol and beat for 120 minutes to obtain a slurry with a solid content of 30% by weight, adjust the pH value of the slurry to 3.0 by adding hydrochloric acid, then continue beating for 30 minutes, add diammonium hydrogen phosphate, and then Slurry was beaten for 30 minutes, and then the obtained slurry was spray-dried under the conditions of an inlet temperature of 500° C. and an exhaust gas temperature of 180° C. to obtain microspheres with an average particle diameter of 65 microns. The microspheres were calcined at 500°C for 1 hour to prepare additive DB ₆ . The ratio of reference additives is shown in Table 4.

Comparative example 13

Take molecular sieve _B4 and kaolin, add decationized water and aluminum sol and beat for 120 minutes to obtain a slurry with a solid content of 30% by weight, add hydrochloric acid to adjust the pH value of the slurry to 3.0, stir for 30 minutes, and add the clay-containing solution provided in Example 9. Phosphorus-aluminum binder, beating for 45 minutes, and then spray-dry the obtained slurry under the conditions of dry air inlet temperature of 500°C and tail gas temperature of 180°C to obtain microspheres with an average particle diameter of 65 microns. The microspheres were calcined at 500°C for 1 hour to obtain the reference additive DB ₇ . The ratio of reference additives is shown in Table 4.

Comparative example 14

Take molecular sieve _B5 , kaolin and pseudo-boehmite, add decationized water and aluminum sol and beat for 120 minutes to obtain a slurry with a solid content of 30% by weight, add hydrochloric acid to make the pH of the slurry 3.0, beat for 45 minutes, and then obtain The slurry was spray-dried to obtain microspheres, and the reference additive DB ₈ was prepared. The ratio of reference additives is shown in Table 4.

Examples 19-26

The following examples take a fixed fluidized bed reactor as an example to illustrate the cracking reaction effect of the cracking aid provided by the present invention.

30 grams of ZJ ₁ -ZJ ₈ were subjected to aging treatment for 12 hours at 800° C. and 100% water vapor atmosphere. Different amounts of aged ZJ ₁ -ZJ ₈ were mixed with different amounts of industrial FCC equilibrium catalyst (industrial grade MLC-500 FCC equilibrium catalyst, main properties are shown in Table 5). The catalyst mixture is loaded into the reactor of a small-scale fixed fluidized bed reactor, and the raw oil shown in Table 6 is subjected to catalytic cracking (see Table 6 for the properties of the raw oil). Table 7 and Table 8 show the weight composition of the catalyst mixture used, the reaction conditions and the reaction results.

Comparative example 15-23

The following comparative examples take a fixed fluidized bed reactor as an example to illustrate the use of reference additives.

The same feedstock oil was subjected to catalytic cracking according to the method in Example 19, except that the catalysts used were 100% industrial FCC equilibrium catalysts, and a mixture of DB ₁ -DB ₈ and industrial FCC equilibrium catalysts. Table 7 and Table 8 show the weight composition of the catalyst mixture used, the reaction conditions and the reaction results.

As can be seen from Table 7 and Table 8, compared with the auxiliary agent prepared by the existing method, the catalytic auxiliary agent provided by the present invention has a higher catalytic cracking liquefied gas yield, and the propylene concentration in the catalytic cracking liquefied gas is higher , better coke and dry gas selectivity, higher heavy oil conversion capacity, and unexpectedly higher liquid recovery.

table 5

Table 6

Claims (19)

1. assistant for calalytic cracking that improves density of propylene contains modification MFI molecular sieve in butt 10～75 % by weight, in the phosphorus aluminium inorganic binder that contains the first clay of al composition, phosphorus component and the first clay butt weight sum 3～30 % by weight, in other inorganic binders of oxide 3～30 % by weight with in the second clay of butt 0～60 % by weight; Wherein, take the described phosphorus aluminium inorganic binder butt weight that contains the first clay as benchmark, the described phosphorus aluminium inorganic binder that contains the first clay comprises with Al ₂O ₃The meter 15～40 % by weight al compositions, with P ₂O ₅The phosphorus component of meter 45～80 % by weight and in the first clay of butt 1～40 % by weight, and its P/Al weight ratio is 1～6; Described modification MFI molecular sieve, its anhydrous chemical expression is counted with the weight of oxide: (0～0.3) Na ₂O (0.5～6) Al ₂O ₃(1.3～10) P ₂O ₅(0.7～15) M _xO _y(70～97) SiO ₂X represents the atomicity of described transition metal M, y represents to satisfy the required number of oxidation state of described transition metal M, described transition metal M is one or more in Fe, Co, Ni, Cu, Mn, Zn, Sn, Bi preferably, and the infrared spectrum that described modification MFI molecular sieve obtains as probe molecule with trimethylpyridine is at 1633cm ^-1The place is without absworption peak.

2. according to auxiliary agent claimed in claim 1, it is characterized in that, described modification MFI molecular sieve rich surface phosphorus, its Phosphorous distribution D is greater than 1, wherein D=P _(S)/ P _(C), described P _(S)Expression adopt zeolite crystal that the TEM-EDX method characterizes from the edge 1/10th phosphorus content to the center, P _(C)The phosphorus content of expression zeolite crystal center.。

3. according to auxiliary agent claimed in claim 2, it is characterized in that, described modification MFI molecular sieve Phosphorous distribution D is 1.15～9: 1.

4. according to claim 1,2 or 3 described auxiliary agents, it is characterized in that, described its anhydrous chemical expression of modification MFI molecular sieve is: (0～0.2) Na ₂O (0.9～5.5) Al ₂O ₃(1.5～7) P ₂O ₅(0.9～10) M _xO _y(82～92) SiO ₂

5. according to auxiliary agent claimed in claim 1, it is characterized in that, described MFI molecular sieve is one or more among ZSM-5, ZSM-8 or the ZSM-11.。

6. according to each described auxiliary agent of claim 1～5, it is characterized in that, described auxiliary agent contains with P ₂O ₅Meter is no more than the phosphorus additive of 15 % by weight.

7. according to auxiliary agent claimed in claim 6, it is characterized in that, this auxiliary agent comprises the phosphorus aluminium inorganic binder that contains the first clay of 8～25 % by weight, the described modification MFI molecular sieve of 20～60 % by weight, the second clay of 10～45 % by weight, other inorganic binder of 5～25 % by weight and the phosphorus additive of 0～10 % by weight.

8. according to auxiliary agent claimed in claim 1, it is characterized in that, described the first clay is one or more in kaolin, sepiolite, concave convex rod, rectorite, imvite and the diatomite; In described the second clay sepiolite, concave convex rod, rectorite, imvite and the diatomite one or more; Described the second clay is in kaolin, metakaolin, diatomite, sepiolite, attapulgite, montmorillonite and the rectorite one or more; Described other inorganic matter binding agent is one or more in boehmite, aluminium colloidal sol, silicon-aluminum sol, waterglass and the phosphorus aluminium colloidal sol.

9. the preparation method of an assistant for calalytic cracking comprises modification MFI molecular sieve, the phosphorus aluminium inorganic binder that contains the first clay, other inorganic binder is mixed, and adds or do not add the second clay, making beating, spray-drying; Wherein, the described phosphorus aluminium inorganic binder that contains the first clay take its butt weight as benchmark, contains with Al ₂O ₃The meter 15～40 % by weight al compositions, with P ₂O ₅The phosphorus component of meter 45～80 % by weight and in the first clay of butt 1～40 % by weight, its P/Al weight ratio is that 1～6, pH is 1～3.5, this binding agent solid content is 15～60 % by weight; Described modification MFI molecular sieve, its anhydrous chemical expression is counted with the weight of oxide: (0～0.3) Na ₂O (0.5～6) Al ₂O ₃(1.3～10) P ₂O ₅(0.7～15) M _xO _y(70～97) SiO ₂, x represents the atomicity of described transition metal M, y represents to satisfy the required number of oxidation state of described transition metal M; Described transition metal M is one or more in Fe, Co, Ni, Cu, Mn, Zn, Sn, Bi preferably; The infrared spectrum that described modification MFI molecular sieve obtains as probe molecule with trimethylpyridine is at 1633cm ^-1The place is without absworption peak.

10. in accordance with the method for claim 9, it is characterized in that, the described phosphorus aluminium inorganic binder preparation method who contains the first clay comprises:

(1) alumina source, the first clay and water making beating are dispersed into the slurries that solid content is 8～45 % by weight; Described alumina source is can be by the aluminium hydroxide of sour peptization and/or aluminium oxide, in the first clay of butt and with Al ₂O ₃The weight ratio of the alumina source of meter is 1～40: 15～40;

(2) stir in the lower slurries that obtain toward step (1) part by weight adding SPA according to P/Al=1～6;

(3) slurries that step (2) obtained reacted 15～90 minutes under 50～99 ℃ of temperature.

11. in accordance with the method for claim 10, it is characterized in that, the described phosphorus aluminium inorganic binder that contains the first clay take its butt weight as benchmark, comprises the Al that 15～35 % by weight are derived from described alumina source ₂O ₃, 50～75 % by weight P ₂O ₅The first clay with 8～35 % by weight.

12. according to claim 10 or 11 described methods, it is characterized in that, described P/Al weight ratio is 2～5.

13. in accordance with the method for claim 10, it is characterized in that, described alumina source is one or more in ρ-aluminium oxide, χ-aluminium oxide, η-aluminium oxide, gama-alumina, κ-aluminium oxide, δ-aluminium oxide, θ-aluminium oxide, gibbsite, surge aluminium stone, promise diaspore, diaspore, boehmite and the boehmite; Described the first clay is one or more in kaolin, sepiolite, concave convex rod, rectorite, imvite and the diatomite.

14. in accordance with the method for claim 10, it is characterized in that, the temperature described in the step (3) is 65～90 ℃.

15. in accordance with the method for claim 9, it is characterized in that, the preparation method of described modification MFI molecular sieve, be included in the molecular sieve with MFI structure of ammonium exchange and introduce phosphorus and transition metal, wherein, described phosphorus divides two parts to introduce, and a part of phosphorus is introduced after transition metal is introduced, and a part of phosphorus is introduced before introducing transition metal or with transition metal simultaneously in addition; The anhydrous chemical expression of described modification MFI molecular sieve is counted with the weight of oxide: (0～0.3) Na ₂O (0.5～6) Al ₂O ₃(1.3～10) P ₂O ₅(0.7～15) M _xO _y(70～97) SiO ₂, x represents the atomicity of described transition metal M, and y represents to satisfy the required number of oxidation state of described transition metal M, and described transition metal M is selected from one or more among Fe, Co, Ni, Cu, Mn, Zn, Sn, the Bi.

16. in accordance with the method for claim 15, it is characterized in that, among the preparation method of described modification MFI molecular sieve, the phosphorus of introducing after transition metal is introduced accounts for 10～90% of total phosphorus in the molecular sieve.

17. according to claim 15 or 16 described methods, it is characterized in that, the mol ratio of transition metal is 0.25～10: 1 in the phosphorus of introducing after transition metal is introduced and the molecular sieve.

18. in accordance with the method for claim 17, it is characterized in that, described phosphorus and the transition metal introduced in the molecular sieve with MFI structure of ammonium exchange comprises with phosphorus-containing compound solution and the solution that contains transistion metal compound and described molecular sieve flooded modification, then drying, 400～800 ℃ of roastings; Wherein the phosphorus-containing compound solution impregnation is carried out twice at least.

19. in accordance with the method for claim 18, it is characterized in that, describedly with phosphorus-containing compound solution and the solution that contains transistion metal compound described molecular sieve is flooded modification and comprise: the filter cake after the ammonium exchange is mixed with the part phosphorus-containing compound that comprises amount of calculation and the solution of metal-containing compound, at 400～800 ℃ of roasting temperatures, the solution with the phosphorus-containing compound that is left mixes again after dry or dry.

Images