CN102847551B - Cracking aid for improving lower-carbon olefin concentration - Google Patents

Abstract

A cracking aid for increasing the concentration of low-carbon olefins, which contains phosphorus-aluminum inorganic binder containing the first clay, modified MFI molecular sieve, other inorganic binders and Group VIII metal additives, with or without the second clay, the The phosphor-aluminum inorganic binder _containing the first clay includes 15-40% by weight _of aluminum components based on _Al2O3 , 45-80% by weight of phosphorus components based on _P2O5 , and 1 ~40% by weight of the first clay. The cracking aid is used for catalytic cracking of petroleum hydrocarbons, can increase the yield of catalytic cracking liquefied gas, significantly increases the concentration of low-carbon olefins, especially propylene, in the liquefied gas, and has a higher conversion capacity of heavy oil.

Description

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

technical field

The invention relates to a cracking aid for increasing the concentration of low-carbon olefins 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 world's demand for propylene is increasing year by year. 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 matrix, 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 is also reported that the introduction of phosphorus compounds into the matrix can improve the selectivity of catalysts or additives to low-carbon olefins.

USP 2002/0003103 A1 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/A1 ratio is 0.1-10. The process can greatly increase the production of low-carbon olefins, especially increase the yield of propylene.

USP 2002/0049133 A1 discloses a catalyst with high zeolite content and high wear resistance. _The catalyst contains 30 to 85% by weight of ZSM-5 zeolite, 6 to 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 relevant 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, the yield and selectivity of C ₂ -C ₄ olefins can be improved, and the yield of liquefied gas is higher.

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)SiO ₂ , wherein M1 is selected from one of the transition metals Fe, Co and Ni, and M2 is selected from Any one 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. When the zeolite materials and catalysts disclosed in the prior art are used in the catalytic cracking process, the concentration of propylene in the liquefied gas is not high, and due to the addition of additives, especially when the amount is large, the main catalyst is diluted and the catalyst composition is weakened. Heavy oil conversion capacity.

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 is applied in catalytic cracking and can increase the concentration of propylene in catalytic cracking liquefied gas.

The invention provides a kind of catalytic cracking auxiliary agent, based on the dry basis weight of the auxiliary agent, containing 10% to 75% by weight of modified MFI molecular sieve on a dry basis, with Al ₂ O ₃ (containing phosphorus from the first clay) Al ₂ O ₃ in the aluminum component of the aluminum inorganic binder), P ₂ O ₅ (the P ₂ O ₅ in the phosphorus component of the phosphorus-aluminum inorganic binder containing the first clay) and the dry basis weight of the first clay And 3～30% by weight of the phosphorus-aluminum inorganic binder containing the first clay, other inorganic binders of 3～30% by weight in oxide, the second clay of 0～60% by weight in dry basis and 0.5% to 15% by weight of metal additives of group VIII based on oxides; wherein, based on the dry weight of the phosphorus-aluminum inorganic binder containing the first clay, the phosphorus-aluminum inorganic binder containing the first clay The binder includes 15-40% by weight of aluminum components based on _Al2O3 , 45-80% _by weight of phosphorus components based on _P2O5 , and 1-40% by weight of _the first clay based on dry basis, and its P /Al weight ratio is 1～6; Described modified MFI molecular sieve is the molecular sieve with MFI structure containing phosphorus and transition metal, and its anhydrous chemical expression is calculated by the weight of 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 , x represents the atom of the transition metal M number, y represents a number required to satisfy the oxidation state of the transition metal M, and the transition metal M is selected from one or more of Fe, Co, Ni, Cu, Mn, Zn, Sn, and Bi.

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, The step of drying and introducing the Group VIII metal additive; wherein, based on the dry weight of the first clay-containing phosphorus-aluminum inorganic binder, the first clay-containing phosphorus-aluminum inorganic binder contains 15-40% by weight of components based on Al ₂ O ₃ , 45-80% by weight of phosphorus components based on P ₂ O ₅ and 1-40% by weight of the first clay on a dry basis, the phosphorus contained in the first clay The P/Al weight ratio of the aluminum inorganic binder is 1-6, the pH value is 1-3.5, and the solid content is 15-60% by weight.

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 . Group VIII metals involved in modified MFI molecular sieves are not considered as Group VIII metal additives.

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

The Group VIIIB metal is preferably one or more of Fe, Co and Ni, among which Fe is more preferred.

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 ertronite species or several.

The other inorganic binders are selected from one or more of the inorganic oxides commonly used in catalytic cracking aids or catalyst substrates and binder components, such as pseudo-boehmite, aluminum sol, silica-alumina sol One or more of water glass and aluminum phosphate sol.

The catalytic promoter provided by the present invention may also contain a phosphorus additive of no more than ₂₅ % by weight based on _P2O5 , and the phosphorus additive is derived from a phosphorus compound, including one of phosphorus inorganic compounds and organic compounds Or several, can be easily soluble in water, can also be insoluble in water or insoluble phosphorus compounds, such as selected from phosphorus oxides, phosphoric acid, phosphate, phosphite, hypophosphite, basic One or more of phosphate, 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 auxiliary agent, the phosphorus additive exists in the form of a phosphorus compound (for example, one or more of phosphorus oxides, phosphates, phosphites, alkali phosphates, and acid phosphates). The phosphorus additive can exist in any possible position of the auxiliary agent, such as it can exist in the inside of the channel of the zeolite, on the surface of the zeolite, it can exist in the matrix material, and it can also exist in the inside of the channel of the zeolite, on the surface of the zeolite and in the matrix material. The content of the phosphorus additive does not include the amount of phosphorus involved in the modified MFI molecular sieve, nor does it include the amount of phosphorus involved in the phosphorus-aluminum inorganic binder containing the first clay.

The auxiliary agent provided by the present invention adopts the modified MFI molecular sieve containing phosphorus and transition metal as the active component and an appropriate amount of clay-containing phosphorus-aluminum inorganic binder. The yield of catalytic cracking liquefied gas can also significantly increase the concentration of low-carbon olefins in catalytic cracking liquefied gas, especially propylene, significantly improve the selectivity of catalytic cracking reaction process for propylene, and increase the octane number of catalytic cracking gasoline; improve the catalyst The heavy oil conversion ability of the composition can reduce the dry gas and coke yield. For example, the industrial DVR-3 balancer is reacted at 480°C, the weight hourly space velocity is 16h ^-1 , and the agent-oil ratio is 5. The conversion rate is 64.91% by weight, the yield of liquefied gas is 15.31% by weight, and the yield of propylene is The propylene concentration in the liquefied gas was 31.09 wt%, the coke selectivity was 9.34 wt%, and the dry gas selectivity was 2.26 wt%. And the phosphorus-aluminum inorganic binder containing 55% by weight of modified ZSM-5 molecular sieves provided by the invention, 6% by weight of kaolin, 8% by weight of pseudoboehmite, 5% by weight of aluminum sol, and 24% by weight of rectorite And the auxiliary agent of 2% by weight iron additive, after mixing with above-mentioned DVR-3 balancing agent with the weight ratio of 10:90, carry out reaction under the same condition, conversion rate is 66.3% by weight, and liquefied gas production rate is 20.65% by weight, The propylene yield was 8.06% by weight, the propylene concentration in the liquefied gas was 39.03% by weight, the coke selectivity was 9.11% by weight, and the dry gas selectivity was 2.25% by weight.

Detailed ways

In the catalytic cracking additive provided by the present invention, the MFI molecular sieve is preferably ZSM-5, the transition metal M is preferably Fe, and its anhydrous chemical expression is preferably (0-0.2) Na in terms of oxide weight. ₂ O·(0.9-3.5)Al ₂ O ₃ ·(1.5-7)P ₂ O ₅ ·(0.9-10)M _x O _y ·(82-92)SiO ₂ .

The catalytic cracking aid provided by the present invention preferably includes 8 to 25% by weight of the phosphorus-aluminum inorganic binder containing the first clay, 20 to 60% by weight of modified MFI molecular sieves, 10 to 45% by weight of clay, 5% by weight -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 phosphorus involved in the modified MFI molecular sieve, nor does it include the phosphorus involved in the phosphorus-aluminum inorganic binder containing the first clay.

_The phosphor-aluminum inorganic binder containing the first clay, based _on its dry weight, contains 15 to 40% by weight of aluminum components as _Al2O3 , and 45 to 80% by weight as _P2O5 The phosphorus component and the first clay of 1-40% by weight 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. 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 8-35% by weight of the first clay on a dry basis have a P/Al weight ratio of 2.0-5.0 and a pH of 1.0-3.5. The P/Al weight ratio is the weight ratio of the phosphorus component calculated as phosphorus element and the aluminum component calculated as aluminum element.

The cracking aid provided by the present invention, wherein said other inorganic binders are selected from one or more of the inorganic oxides commonly used in catalytic cracking aids or catalyst substrates and binder components, such as pseudoboehmite A mixture of one or more of stone, alumina sol, phosphoraluminate, silica-alumina sol, and water glass, among which one or more of pseudo-boehmite, alumina sol, and phosphoraluminate are preferred. 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, it is considered that a phosphorus additive has been introduced, and the content of phosphorus introduced by it is the same as that of other phosphorus The sum of the phosphorus contents (calculated as P ₂ O ₅ ) introduced by the additives does not exceed 25% by weight.

In the preparation method of the catalytic cracking aid provided by the present invention, the first clay-containing phosphorus-aluminum compound inorganic binder contains 15 to 40% by weight of aluminum in terms of Al ₂ O ₃ on the basis of its dry weight. Components, 45-80% by weight phosphorus component based on P ₂ O ₅ and 1-40% by weight of the first clay based on dry basis have a P/Al weight ratio of 1.0-6.0 and a pH of 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 in terms of elements 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 said 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; said The P/Al weight ratio of is preferably 1.2 to 6.0, more preferably 2.0 to 5.0. 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 gibbsite, diaspore, boehmite and pseudo-boehmite. The aluminum component is derived from the aluminum 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.

In the preparation process of the phosphorus-aluminum inorganic binder containing the first clay provided by the present invention, clay, alumina source, concentrated phosphoric acid and water are mixed and reacted without introducing chlorine to obtain the chlorine-free phosphorus-aluminum inorganic binder containing the first clay. Binder. Due to the introduction of clay, it not only improves the mass transfer and heat transfer between materials during the preparation process, but also avoids the curing of the phosphorus-aluminum adhesive caused by the exothermic overheating caused by the inhomogeneous local instantaneous violent reaction of the materials. Moreover, the method introduces clay, especially retort clay with a layered structure, which improves the heavy oil conversion capability of the catalyst composition and makes the obtained additives have better selectivity.

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 phosphorus-aluminum inorganic binder containing the first clay, other inorganic binders, modified MFI molecular sieves, and the second clay can be mixed (the related adding step can be omitted when the second clay is not included) and beaten. Preferably, water, modified MFI molecular sieves, other inorganic binders and clay are mixed, and after beating for 15 to 60 minutes, the phosphorus-aluminum inorganic binder containing the first clay is added, which is beneficial to improve the wear resistance of the catalyst loss performance, heavy oil cracking performance and selectivity.

The preparation method of the catalytic cracking additive provided by the present invention also includes the step of drying and shaping the slurry obtained by the beating. The drying is, for example, spray drying. The method of spray drying is well known to those skilled in the art, and the present invention has no special requirements.

In the preparation method of catalytic cracking additives provided by the present invention, the introduction of Group VIII metal additives can be introduced by adding Group VIII metal compounds into the slurry in any step before the drying and molding of the additive preparation process, and can also be introduced during the drying of the additives. Introduced after shaping by impregnation or chemisorption of Group VIII metal compounds followed by calcination. Introduction after drying and molding, including impregnation or chemical adsorption treatment of additives with an aqueous solution containing a transition metal compound, followed by solid-liquid separation (if necessary), drying and calcination, 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. Preferably, the Group VIII metal additives are introduced before drying and forming. The Group VIII metal additive may be one or more of inorganic compounds and organic compounds of Group VIII metals, and may be easily water-soluble, or poorly water-soluble or water-insoluble compounds. Examples of Group VIII metal compounds include oxides, hydroxides, chlorides, nitrates, sulfates, phosphates and organic compounds thereof. Preferred transition metal compounds are selected from one or more of their chlorides, nitrates, sulfates and phosphates.

The transition metal additive can exist in any possible position of the auxiliary agent, such as inside the pores of the zeolite, on the surface of the zeolite, in the matrix material, or at the same time inside the pores of the zeolite, on the surface of the zeolite and on the surface of the zeolite. Among the matrix materials, preferably present in the matrix material. The Group VIII metal additives may be present in the form of their oxides, phosphates, phosphites, basic phosphates, acid phosphates.

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 additive provided by the present invention accounts for 1-30% by weight, preferably 3-20% by weight, of the total amount of the FCC catalyst and the catalyst mixture provided by the present invention. The hydrocarbon oil is selected from various petroleum fractions, such as crude oil, atmospheric residue, vacuum residue, atmospheric gas oil, vacuum gas oil, straight-run gas oil, propane light/heavy deoiling, coker gas oil and One or more of 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 a weight ratio of agent to oil of 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 are not intended to limit the content of the present invention.

In the examples, five modified ZSM-5 molecular sieve samples from A ₁ to A ₅ were prepared by the method disclosed in CN1465527A, and their anhydrous chemical expressions were obtained by measuring the elemental composition of molecular sieves by X-ray fluorescence spectrometry, and then converted .

Sample A ₁ : 0.04Na ₂ O·3.57Al ₂ O ₃ ·4.0P ₂ O ₅ ·2.4Fe ₂ O ₃ ·90.49SiO ₂ .

Sample A ₂ : 0.1Na ₂ O·5.3Al ₂ O ₃ ·1.5P ₂ O ₅ ·1.1Fe ₂ O ₃ ·92SiO ₂ .

Sample A ₃ : 0.1Na ₂ O·0.94Al ₂ O ₃ ·5.1P ₂ O ₅ ·10.1Fe ₂ O ₃ ·84SiO ₂ .

Sample A ₄ : 0.03Na ₂ O·5.1Al ₂ O ₃ ·4.8P ₂ O ₅ ·3.6Co ₂ O ₃ ·86.5SiO ₂ .

Sample A ₅ : 0.1Na ₂ O·4.6Al ₂ O ₃ ·6.9P ₂ O ₅ ·6.4Ni ₂ O ₃ ·82SiO ₂ .

Pseudoboehmite is an industrial product produced by Shandong Aluminum Works, with a solid content of 60% by weight; aluminum sol (also known as aluminum chloride-containing sol in the present invention) is an industrial product produced by Qilu Petrochemical Catalyst Factory, with _{an Al2O3} content of 21.5% by weight Water glass is the industrial product that Qilu Petrochemical Catalyst Factory produces, and SiO ₂ content 28.9% by weight, Na ₂ O content 8.9%; Kaolin is the cracking catalyst special kaolin that Suzhou Kaolin Company produces, solid content 78% by weight; ZRP-5 zeolite is An industrial product of conventional MFI structure zeolite produced by Qilu Petrochemical Catalyst Factory, wherein P ₂ O ₅ is 2.5% by weight, crystallinity is 85% by weight, and the ratio of silicon to aluminum is 50. Rectorite: 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; 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 1-4 Prepare the phosphorus-aluminum inorganic binder containing clay used in the present invention, and the formula and composition are shown in Table 1.

Example 1

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 0.03Kg phosphoric acid/min/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 1.

Embodiment 2-4

According to Example 1, the clay-containing phosphorus-aluminum inorganic binder of the present invention was prepared. The material ratio is shown in Table 1.

Comparative example 1

In this comparative example, the phosphorus-aluminum inorganic binder was prepared according to the existing method.

Preparation of phosphate-aluminum sol: 0.66 kg of pseudoboehmite (0.44 kg on a dry basis) and 1.75 kg of decationized water were beaten for 30 minutes, and 2.6 kg of concentrated phosphoric acid (chemically pure, containing 85% by weight of phosphoric acid) was slowly added to the slurry under stirring , the temperature was raised to 70° C., and then reacted at this temperature for 45 minutes to obtain a phosphorus-aluminum inorganic binder. The material ratio is shown in Table 1.

Example 5

Take molecular sieve A ₁ , kaolin and pseudo-boehmite, add decationized water and aluminum sol to beat for 120 minutes, add FeCl ₃ .6H ₂ O aqueous solution (FeCl ₃ concentration 30% by weight) under stirring, and obtain a solid content of 30% by weight % slurry, the pH value of the slurry was adjusted to 3.0 with hydrochloric acid, then beating for 45 minutes, adding the clay-containing phosphorus-aluminum binder provided in Example 2, stirring for 30 minutes, and spray-drying the obtained slurry to obtain microspheres, The microspheres were calcined at 500°C for 1 hour to prepare the additive ZJ ₁ . The formula is shown in Table 2.

Example 6

Take molecular sieve A ₂ , kaolin and pseudo-boehmite, add decationized water and aluminum sol to beat for 120 minutes, add Co(NO ₃ ) ₂ ·6H ₂ O aqueous solution (Co(NO ₃ ) ₂ concentration 30% by weight) under stirring ), to obtain a solid content of 30% by weight slurry, add hydrochloric acid to adjust the pH value of the slurry to 3.0, continue beating for 45 minutes, then add the clay-containing phosphorus-aluminum binder that Example 1 provides in the mixed slurry, and stir for 45 minutes. Minutes, 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 fired at 500°C for 1 hour.

Take 1 kg (dry basis) of the obtained microsphere product, add 10 kg of diammonium hydrogen phosphate aqueous solution with a concentration of 5% by weight, heat up to 60° C. under stirring, react at this temperature for 20 minutes, vacuum filter and dry the slurry , and then calcined at 500°C for 2 hours to prepare the auxiliary agent ZJ ₂ . The formula is shown in Table 2.

Example 7

Take molecular sieve A ₃ , kaolin, diatomite and pseudo-boehmite, add decationized water and water glass and beat for 120 minutes, add hydrochloric acid to adjust the pH value of the slurry to 3.0, beat for 45 minutes, add diammonium hydrogen phosphate solid, and then Add the phosphorus-aluminum inorganic binder containing clay prepared in Example 3 to the slurry, stir for 30 minutes to obtain a slurry with a solid content of 38% by weight, and then spray-dry the obtained slurry to obtain microspheres with an average particle diameter of 65 microns. The microspheres were fired at 500°C for 1 hour.

Take the obtained calcined microspheres, mix them with an aqueous solution of 1.5% by weight FeCl ₃ ·6H ₂ O, react at 60°C for 20 minutes, filter, dry, and then calcinate at 500°C for 2 hours to obtain the auxiliary agent ZJ ₃ . The formula is shown in Table 2.

Example 8

Take molecular sieve A ₄ , kaolin and pseudo-boehmite, add decationized water and beat for 120 minutes, add Co(NO ₃ ) ₂ ·6H ₂ O aqueous solution (the concentration of Co(NO ₃ ) ₂ is 30% by weight) while stirring, Add hydrochloric acid to adjust the pH value of the slurry to 3.0, beating for 45 minutes to obtain a slurry with a solid content of 30% by weight, then add the clay-containing phosphorus-aluminum binder prepared in Example 4 to the slurry, spray dry, and obtain an average particle diameter of 65 For micron microspheres, the microspheres are calcined at 500°C for 1 hour to prepare the additive ZJ ₄ . The formula is shown in Table 2.

Example 9

Take molecular sieve A ₅ , add decationized water for beating for 120 minutes, add Ni(NO ₃ ) ₂ ·6H ₂ O aqueous solution (Ni(NO ₃ ) ₂ concentration 30% by weight) under stirring, add hydrochloric acid to make the pH value of the slurry 3.0, Beat for 45 minutes to obtain a slurry with a solid content of 30% by weight, then add the clay-containing aluminum-phosphate binder prepared in Example 4 and the phosphorus-aluminum glue prepared in Comparative Example 1, and spray dry to obtain microspheres with an average particle diameter of 65 microns , the microspheres were calcined at 500°C for 1 hour to prepare the additive ZJ ₅ . The formula is shown in Table 2.

Comparative example 2

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, adjust the pH value of the slurry to 3.0 by adding hydrochloric acid, and continue beating for 45 minutes , and then add the clay-containing phosphorus-aluminum binder provided in Example 2 to the mixed slurry, and after stirring evenly, the resulting slurry is spray-dried to obtain microspheres with an average particle diameter of 65 microns, and the microspheres are roasted at 500 ° C After 1 hour, adjuvant _DB1 was prepared. The formula is shown in Table 3.

Comparative example 3

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, and add FeCl ₃ ·6H ₂ O aqueous solution (FeCl ₃ concentration 30% by weight) while stirring. % by weight, the same below), add hydrochloric acid to adjust the pH value of the slurry to 3.0, beating for 45 minutes, then add diammonium hydrogen phosphate to the slurry, stir for 30 minutes, obtain a slurry with a solid content of 30% by weight, and spray the obtained slurry Drying yielded microspheres with an average particle diameter of 65 microns. The microspheres were calcined at 500°C for 1 hour to prepare additive DB ₂ . The formula is shown in Table 3.

Comparative example 4

Take molecular sieve A ₁ , kaolin and pseudo-boehmite, add decationized water and aluminum sol to beat for 120 minutes, add FeCl ₃ ·6H ₂ O aqueous solution under stirring to obtain a slurry with a solid content of 30% by weight, adjust the slurry by adding hydrochloric acid The pH value of the slurry was 3, and the beating was continued for 45 minutes, and then the phosphorus-aluminum binder provided in Comparative Example 1 was added to the slurry, and after stirring evenly, it was spray-dried 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 ₃ . The formula is shown in Table 3.

Comparative example 5

Take molecular sieve A1, kaolin and pseudo-boehmite, add decationized water and aluminum sol to beat for 120 minutes, add FeCl3·6H ₂ O aqueous solution under stirring, add hydrochloric acid to adjust the pH value of the slurry to 3, continue beating for 45 minutes, stir After homogenization, the resulting slurry was spray-dried to obtain microspheres with an average particle diameter of 65 microns, and the microspheres were calcined at 500°C for 1 hour to prepare additive DB ₄ . The formula is shown in Table 3.

Comparative example 6

Same as Comparative Example 2, except that molecular sieve A ₁ is replaced by ZRP-5 to prepare additive DB ₅ . The formula is shown in Table 3.

Comparative example 7

Take molecular sieve ZRP-5, kaolin, diatomite and pseudo-boehmite, add decationized water and water glass and beat for 120 minutes, add FeCl ₃ 6H ₂ O aqueous solution under stirring, add hydrochloric acid to adjust the pH value of the slurry to 3, Then beating for 45 minutes, then adding diammonium hydrogen phosphate, stirring evenly, spray drying to obtain microspheres with an average particle diameter of 65 microns, and roasting the microspheres at 500°C for 1 hour to prepare additive DB ₆ . The formula is shown in Table 3.

Comparative example 8

Take molecular sieve ZRP-5 and kaolin, add decationized water and pseudo-boehmite and beat for 120 minutes, add hydrochloric acid to adjust the pH value of the slurry to 3, beat for 45 minutes, spray dry the obtained slurry, and obtain an average particle diameter of 65 For micron microspheres, the microspheres were calcined at 500°C for 1 hour to prepare additive DB ₇ . The formula is shown in Table 3.

Examples 10-16

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 ₅ were subjected to aging treatment for 8 hours at 800° C. and 100% water vapor atmosphere. Different weights of aged ZJ ₁ -ZJ ₅ were mixed with different weights of industrial FCC equilibrium catalyst (industrial grade DVR-3 FCC equilibrium catalyst, main properties are shown in Table 4). The catalyst mixture is loaded into the reactor of the small-scale fixed fluidized bed reactor, and the raw oil shown in Table 5 is subjected to catalytic cracking (the properties of the raw oil are shown in Table 5). Table 6 and Table 7 show the weight composition of the catalyst mixture used, the reaction conditions and the reaction results.

Comparative example 9-16

The same raw oil was subjected to catalytic cracking according to the method of Example 10, except that the catalysts used were 100% industrial FCC equilibrium catalyst, and a mixture of DB ₁ -DB ₇ and industrial FCC equilibrium catalyst. Table 6 and Table 7 provide the composition of the catalyst mixture used, the reaction conditions and the reaction results.

Comparative example 17

Prepare phosphorus-aluminum sol according to the method for comparative example 1, difference is, with SB powder and phosphoric acid reaction, the add-on of SB powder is 0.37Kg, the add-on of 85% by weight phosphoric acid is 2.14Kg, the water add-on is 4.31Kg, then Add 0.52Kg retort earth in the obtained phosphorus aluminum sol and make a slurry, obtain the mixture of rector earth and phosphorus aluminum glue, denote as Dbinder, then use this mixture to replace Binder 3 in embodiment 7 to obtain auxiliary agent DB8, then according to implementation The method of Example 12 evaluated DB ₈ , and the results are shown in Table 7.

It can be seen from Table 6 and Table 7 that compared with the existing additives, the catalytic additive provided by the present invention has a higher yield of catalytic cracking liquefied gas, can significantly improve the concentration of propylene in catalytic cracking liquefied gas, and has a higher High propylene yield and higher conversion rate, even when a large proportion is added, the heavy oil conversion capacity is still high, and surprisingly, it also has a high liquid recovery.

Table 1

Table 2

table 3

Table 4

table 5

Table 6

Table 7

Claims (13)

1. A catalytic cracking additive for improving the concentration of propylene in liquefied gas, based on the dry weight of the additive, containing 10 to 75% by weight of modified MFI molecular sieve on a dry basis, with Al ₂ O ₃ , P The sum of ₂ O ₅ and the dry basis weight of the first clay is 3-30% by weight of the phosphorus-aluminum inorganic binder containing the first clay, 3-30% by weight of other inorganic binders by oxide, and 3-30% by weight of other inorganic binders by oxide 0.5 to 15% by weight of Group VIII metal additives and 0 to 60% by weight of the second clay on a dry basis; wherein, based on the dry weight of the phosphor-aluminum inorganic binder containing the first clay, the The phosphorus-aluminum inorganic binder containing the _first clay comprises 15-40% by weight of an aluminum component based on _Al2O3 , 45-80% by weight of a phosphorus component based on _P2O5 , and 1-40% by weight on a dry basis _. % by weight of the first clay, and its P/Al weight ratio is 1-6; 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 atomic number of M, and y represents the satisfaction of the above M A number required for the oxidation state; the M is selected from one or more of Fe, Co, Ni, Cu, Mn, Zn, Sn, Bi; The preparation method of the phosphorus-aluminum inorganic binder containing the first clay 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) adding concentrated phosphoric acid according to the weight ratio of P/Al=1～6 in the slurry that step (1) obtains under stirring; (3) Reacting the slurry obtained in step (2) at a temperature of 50-99° C. for 15-90 minutes. 2. The additive according to claim 1, characterized in that the anhydrous chemical expression of the modified MFI molecular sieve is: (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 . 3. according to the described auxiliary agent of claim 1, it is characterized in that, described MFI molecular sieve is ZSM-5. 4. according to the described auxiliary agent of claim 1, it is characterized in that, described first clay is one or more in kaolin, sepiolite, attapulgite, retort earth, montmorillonite and diatomite The second clay includes one or more of kaolin, metakaolin, diatomite, sepiolite, attapulgite, montmorillonite and rectorite; the other inorganic binders include pseudothin water One or more of bauxite, alumina sol, silica-alumina sol, water glass and phosphoralumina sol. 5. The auxiliary agent according to claim 1, characterized in that, said Group VIII metal is one or more of Fe, Co and Ni. 6. The auxiliary agent according to any one of claims 1-5, characterized in that the auxiliary agent contains 0-25% by weight of phosphorus additives calculated as P ₂ O ₅ . 7. according to the described auxiliary agent of claim 6, it is characterized in that, this auxiliary agent comprises the phosphor-aluminum inorganic binding agent that contains the first clay of 8～25% by weight, the modified MFI molecular sieve of 20～60% by weight, 10% by weight -45% by weight of secondary clay, 0.5-15% by weight of Group VIII metal additives, 5-25% by weight of other inorganic binders and 0-10% by weight of phosphorus additives. 8. 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, and introducing Group VIII metal additive; wherein, the phosphorus-aluminum inorganic binder containing the first clay, based on its dry weight, contains 15 to 40% by weight of aluminum components based on Al ₂ O ₃ , and based on P ₂ O ₅ 45-80% by weight of the phosphorus component and 1-40% by weight of the first clay on a dry basis, the P/Al weight ratio is 1-6, the pH value is 1-3.5, and the solid content is 15-60% by weight %; The preparation method of the described first clay-containing phosphorus-aluminum 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) adding concentrated phosphoric acid according to the weight ratio of P/Al=1～6 in the slurry that step (1) obtains under stirring; (3) Reacting the slurry obtained in step (2) at a temperature of 50-99° C. for 15-90 minutes. 9. The method according to claim 8, characterized in that the P/Al weight ratio is 2-5. 10. according to the described method of claim 8, it is characterized in that, described alumina source is ρ-alumina, χ-alumina, η-alumina, γ-alumina, κ-alumina, δ-alumina One or more of aluminum, θ-alumina, gibbsite, pyrenite, diaspore, diaspore, boehmite and pseudo-boehmite; the first clay is kaolin , sepiolite, attapulgite, retort earth, montmorillonite and diatomite in one or more. 11. The method according to any one of claims 8 to 10, characterized in that, the first clay-containing phosphorus-aluminum inorganic binder contains 15 to 35% by weight of source _Al2O3 from said alumina source, 50-75% by weight _P2O5 and 8-35% by weight of _the first _clay . 12. The method according to claim 8, characterized in that the temperature in step (3) is 65-90°C. 13. The method according to claim 8 or 9, further comprising the step of introducing a phosphorus additive.