Catalytic promoter for catalytic cracking and preparation method thereof

Abstract

The invention provides a catalytic promoter for catalytic cracking and a preparation method thereof.The catalytic promoter comprises a modified ZSM-5 molecular sieve, a phosphorus-containing compound and a binder, the preparation method of the modified ZSM-5 molecular sieve comprises the steps that 1, the ZSM-5 molecular sieve, an alkaline compound and water are mixed, stirred and filtered, and an alkali-modified ZSM-5 molecular sieve is obtained; step 2, mixing the alkali modified ZSM-5 molecular sieve, an acidic solution and a zinc-containing compound, and stirring; step 3, mixing the slurry obtained in the step 2 with a phosphorus-containing compound, and stirring; and step 4, filtering, drying and roasting the slurry obtained in the step 3 to obtain the modified ZSM-5 molecular sieve. The modified ZSM-5 molecular sieve prepared by the method has rich mesopore and macropore structures and good thermal and hydrothermal stability. The modified ZSM-5 molecular sieve prepared by the method can effectively promote the shape-selective cracking reaction of gasoline components in the catalytic cracking process, improve the yield of liquefied gas and propylene, and improve the content of propylene in the liquefied gas at the same time.

Description

Technical Field

[0001] The invention belongs to the field of catalytic cracking, and specifically relates to a method for preparing a catalyst aid for catalytic cracking, and the catalyst aid prepared by the preparation method. Background Art

[0002] Domestic demand for refined oil products has entered a plateau period, while propylene, as an important chemical raw material, is still maintaining a steady growth rate. At present, only about one-third of domestic propylene comes from catalytic cracking units. Increasing propylene production through catalytic cracking is an important way for oil refining companies to transform into chemical companies. Compared with equipment modification, increasing propylene production through the optimization of catalysts or additives is the most economical, flexible and effective method. With the continuous increase in domestic oil refining companies' demand for propylene, the demand for high-yield propylene catalytic cracking catalysts or additives is also increasing. At present, ZSM-5 molecular sieve is still the main active component of high-yield propylene catalytic cracking catalysts and additives. In order to improve its reaction performance, it is usually necessary to perform post-modification treatment on it.

[0003] CN 107970982A discloses a catalytic cracking additive for increasing propylene production and a preparation method thereof, wherein the additive comprises a phosphorus-containing ZSM-5 molecular sieve, a phosphorus-aluminum inorganic binder, other inorganic binders and clay. The additive is applied to a catalytic cracking process and can effectively increase propylene yield and propylene selectivity.

[0004] CN1796497 discloses a catalytic cracking aid for producing more propylene, which comprises a modified ZSM-5 molecular sieve, clay, an inorganic oxide binder, a magnesium additive and a zinc additive, wherein the modified ZSM-5 molecular sieve is modified with phosphorus. The aid is applied to catalytic cracking to increase the yield of liquefied gas and significantly increase the propylene concentration in the liquefied gas.

[0005] CN111748367A discloses a method for increasing the yield of ethylene and propylene by catalytic cracking / thermal cracking of bio-oil. The main active components of the catalyst used in the process are mainly ⅢA group and P element modified ten-membered ring molecular sieve and alumina, and the yield of ethylene and propylene of the product is high. The ten-membered ring molecular sieve is preferably ZSM-5 molecular sieve.

[0006] CN107970981A discloses a catalytic cracking additive for increasing propylene production and a preparation method thereof. The additive comprises a phosphorus-containing and metal-loaded MFI structure molecular sieve, a phosphorus-aluminum inorganic binder, other inorganic binders, clay and metal additives. The loaded metal is at least one of iron, cobalt, nickel, copper, manganese, tin and bismuth. The additive is applied to a catalytic cracking process and can effectively improve propylene yield and propylene selectivity.

[0007] CN 107185586A discloses a catalytic cracking aid for producing more propylene and isopentene, and a preparation method and application thereof. The catalytic cracking aid for producing more propylene and isopentene comprises alkali-modified ZSM-5 molecular sieve, USY molecular sieve, beta molecular sieve, phosphorus and inorganic oxide. The aid can promote the shape-selective isomerization cracking reaction of gasoline components above C8 in catalytic cracking gasoline, can simultaneously increase the yield of propylene and isopentene, and increase the propylene content in liquefied gas.

[0008] CN101440302B introduces a method for reducing the benzene content in gasoline and a catalyst thereof, wherein the active component of the catalyst contains a modified ZSM-5 molecular sieve. The modifying elements of the ZSM-5 molecular sieve are phosphorus and one or more metals selected from zinc and rare earth metals. The modification method is to prepare a solution of phosphorus, zinc and / or rare earth compounds, then add the ZSM-5 molecular sieve for impregnation, and then dry and roast to obtain the modified ZSM-5 molecular sieve. The catalyst is applied to catalytic cracking to reduce the benzene content in gasoline and effectively increase the propylene yield.

[0009] CN103816936B reports a modified aluminum phosphate molecular sieve and its preparation method. The modification method is to mix ZSM-5 molecular sieve with water, then add phosphorus-containing compounds and zinc-containing compounds, stir evenly, heat to 120-150°C, stir for 120-150min under a certain pressure, then filter, dry and roast to obtain a modified aluminum phosphate molecular sieve. The molecular sieve has a strong B acid center, good thermal and hydrothermal stability, and excellent adsorption performance and cracking performance.

[0010] It can be seen from the above-mentioned prior art that modification of ZSM-5 molecular sieve is a common and effective method to improve the propylene yield of catalytic cracking catalysts or additives. Alkali modification, phosphorus modification, phosphorus and metal composite modification play an important role in adjusting the pore structure, acid distribution, stability, etc. of ZSM-5 molecular sieve, thereby effectively improving the propylene yield of the catalyst. How to further optimize the role of ZSM-5 molecular sieve is the key to further improving the reaction performance of ZSM-5 molecular sieve. Summary of the invention

[0011] The main purpose of the present invention is to provide a catalyst aid for catalytic cracking and a preparation method thereof, so as to further improve the catalytic performance of ZSM-5 molecular sieve.

[0012] In order to achieve the above object, the present invention provides a method for preparing a catalyst promoter for catalytic cracking, wherein the catalyst promoter comprises a modified ZSM-5 molecular sieve, a phosphorus-containing compound and a binder, and the preparation method of the modified ZSM-5 molecular sieve comprises:

[0013] Step 1, mixing ZSM-5 molecular sieve, a basic compound and water, stirring and filtering to obtain a base-modified ZSM-5 molecular sieve;

[0014] Step 2, mixing the base-modified ZSM-5 molecular sieve, the acidic solution and the zinc-containing compound, and stirring;

[0015] Step 3, mixing the slurry obtained in step 2 with the phosphorus-containing compound and stirring;

[0016] Step 4, filtering, drying and calcining the slurry obtained in step 3 to obtain a modified ZSM-5 molecular sieve.

[0017] The method for preparing a catalyst aid for catalytic cracking of the present invention, wherein step 2 further comprises the step of exchanging the alkali-modified ZSM-5 molecular sieve with an ammonium salt, and then mixing and slurrying with an acidic solution.

[0018] The method for preparing a catalyst promoter for catalytic cracking of the present invention, wherein the alkaline compound is an inorganic base or an organic base, the alkaline compound is calculated as an oxide, and the weight ratio of the ZSM-5 molecular sieve to the alkaline compound is 1:0.08-0.5; the temperature for stirring the ZSM-5 molecular sieve and the alkaline compound is 40-100°C, and the stirring time is 0.5-5h.

[0019] The method for preparing a catalyst promoter for catalytic cracking of the present invention, wherein the ammonium salt is one or more of ammonium sulfate, ammonium chloride, ammonium nitrate and ammonium phosphate.

[0020] The method for preparing a catalyst promoter for catalytic cracking of the present invention comprises the following steps: the acidic solution is an organic acid solution or an inorganic acid solution, the concentration of the acidic solution is 0.1-4 mol / L; the zinc-containing compound is a water-soluble zinc-containing salt, the zinc-containing compound is calculated as zinc oxide, and the mass ratio of the zinc-containing compound to the ZSM-5 molecular sieve is 0.1%-2%.

[0021] The method for preparing a catalyst aid for catalytic cracking of the present invention comprises the following steps: in step 2, the temperature for stirring the alkali-modified ZSM-5 molecular sieve and the zinc-containing compound is 40-100° C., and the stirring time is 0.3-3 h.

[0022] The method for preparing a catalyst promoter for catalytic cracking of the present invention, wherein the phosphorus-containing compound is phosphoric acid or phosphate, the phosphorus-containing compound is calculated as phosphorus pentoxide, and the mass ratio of the phosphorus-containing compound to the ZSM-5 molecular sieve is 2%-8%.

[0023] In the method for preparing a catalyst promoter for catalytic cracking of the present invention, the slurry obtained in step 2 is stirred with the phosphorus-containing compound at a temperature of 120-180° C. and a stirring time of 0.2-3 h.

[0024] The method for preparing a catalyst aid for catalytic cracking of the present invention comprises the following steps: the drying temperature in step 4 is 100-120° C., the calcination temperature is 400-700° C., and the calcination time is 0.5-4 h.

[0025] In order to achieve the above object, the present invention also provides a catalyst aid prepared by the above preparation method. Based on the total mass of the modified ZSM-5 molecular sieve, the zinc oxide content in the modified ZSM-5 molecular sieve is 0.1%-2%, and the phosphorus pentoxide content is 2%-8%.

[0026] The catalyst promoter of the present invention, wherein, based on the total dry mass of the catalyst promoter, the content of the modified ZSM-5 molecular sieve is 20%-60%, the content of the phosphorus-containing compound is 2%-20%, and the content of the binder is 2%-20%; the catalyst promoter also includes clay.

[0027] Beneficial effects:

[0028] (1) The catalyst promoter of the present invention includes a modified ZSM-5 molecular sieve, which is first treated with alkali to form a rich medium- and macro-pore structure, which is conducive to the full dispersion of the subsequent modified medium in the pores and reduces the effect of the subsequent modification on the pore blockage of the ZSM-5 molecular sieve.

[0029] (2) More importantly, the zinc modification and phosphorus modification of the present invention are carried out in steps and are carried out under acidic conditions, so that there is no need for roasting after zinc modification and phosphorus modification can be carried out directly, thereby reducing the modification steps and simplifying the modification process.

[0030] (3) The present invention cooperates the steps of alkali modification with zinc exchange and phosphorus exchange of ZSM-5 molecular sieve under acidic medium conditions. Zinc exchange under acidic medium conditions can remove part of the framework aluminum and fragment aluminum of ZSM-5 molecular sieve, further optimize the pore structure, acid distribution and the dispersion of zinc in the pores of ZSM-5 molecular sieve. Then, the ZSM-5 molecular sieve is phosphorus modified. In this way, the modified ZSM-5 molecular sieve has a rich medium and large pore structure and good thermal and hydrothermal stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is the XRD spectrum of the modified ZSM-5 prepared in Example 3. DETAILED DESCRIPTION

[0032] The technical scheme of the present invention is described in detail below. The following implementation modes are implemented on the premise of the technical scheme of the present invention, and a detailed implementation process is given. However, the protection scope of the present invention is not limited to the following implementation modes. The structures or experimental methods of specific conditions are not specified in the following implementation modes, and generally conventional conditions are followed.

[0033] The present invention provides a catalyst aid for catalytic cracking, the catalyst aid comprising a modified ZSM-5 molecular sieve, a phosphorus-containing compound and a binder. In one embodiment, the catalyst aid for catalytic cracking of the present invention further comprises clay. In another embodiment, based on the total dry weight of the catalyst aid for catalytic cracking of the present invention, the content of the modified ZSM-5 molecular sieve is 20%-60%, the content of the phosphorus-containing compound is 2%-20%, the content of the binder is 2%-20%, and the balance is clay.

[0034] In one embodiment, the binder of the present invention is an inorganic binder. The present invention does not particularly limit the type of the inorganic binder, for example, it is one or more of silica sol, aluminum sol, silica-alumina sol, silica-alumina gel, acidified pseudo-boehmite, aluminum phosphate sol, etc., among which aluminum sol and silica sol are preferred.

[0035] In one embodiment, the phosphorus-containing compound in the catalyst promoter for catalytic cracking of the present invention can be phosphoric acid, phosphate, phosphorous acid or phosphite, as long as it contains phosphate or phosphite. For example, phosphoric acid, phosphorous acid, ammonium phosphate, ammonium dihydrogen phosphate, ammonium hydrogen phosphate and other substances containing phosphate, preferably phosphoric acid. The added amount is calculated by the mass of phosphorus pentoxide, accounting for 5-20% of the total mass of the catalyst promoter.

[0036] In one embodiment, the clay of the present invention is one or more of various types of clays such as kaolin, bentonite, sepiolite, diatomaceous earth, attapulgite, and montmorillonite, among which kaolin is preferred.

[0037] The modified ZSM-5 molecular sieve of the present invention is a ZSM-5 molecular sieve that has been treated with alkali, modified with zinc and modified with phosphorus. Based on the total mass of the modified ZSM-5 molecular sieve, the zinc oxide content is 0.1-2%, and the phosphorus pentoxide content is 2-8%.

[0038] The preparation method of the modified ZSM-5 molecular sieve of the present invention comprises:

[0039] Step 1, mixing ZSM-5 molecular sieve, a basic compound and water, stirring and filtering to obtain a base-modified ZSM-5 molecular sieve;

[0040] Step 2, mixing the base-modified ZSM-5 molecular sieve, the acidic solution and the zinc-containing compound, and stirring;

[0041] Step 3, mixing the slurry obtained in step 2 with the phosphorus-containing compound and stirring;

[0042] Step 4, filtering, drying and calcining the slurry obtained in step 3 to obtain a modified ZSM-5 molecular sieve.

[0043] The present invention firstly performs alkali treatment on the ZSM-5 molecular sieve to remove part of silicon species, form a rich medium- and macro-pore structure, improve the pore structure, facilitate the full dispersion of the subsequent modified medium in the pores, and reduce the influence of the subsequent modification on the pore blockage of the ZSM-5 molecular sieve.

[0044] Subsequently, the ZSM-5 molecular sieve is zinc-modified under acidic medium conditions, which can remove part of the framework aluminum and fragment aluminum of the ZSM-5 molecular sieve, further optimizing the pore structure, acid distribution and the dispersion of zinc in the pores of the ZSM-5 molecular sieve. More importantly, zinc and phosphorus are added step by step during the modification process of the ZSM-5 molecular sieve of the present invention, which can promote the dispersion of zinc in the ZSM-5 molecular sieve and the interaction between phosphorus and the molecular sieve, and in an acidic medium, after zinc modification, drying, roasting and other operations can be omitted, and the ZSM-5 molecular sieve can be directly phosphorus-modified, which reduces the modification steps and simplifies the modification process.

[0045] In addition, the modified ZSM-5 molecular sieve wet product of the present invention is directly filtered, dried and roasted, avoiding the traditional impregnation method of drying the entire modified slurry and reducing the modification energy consumption.

[0046] The modified ZSM-5 molecular sieve prepared by the present invention has rich medium and large pore structures and good thermal and hydrothermal stability. The modified ZSM-5 molecular sieve prepared by the present invention can effectively promote the shape-selective cracking reaction of gasoline components in the catalytic cracking process, increase the yield of liquefied gas and propylene, and simultaneously increase the propylene content in the liquefied gas.

[0047] In one embodiment, in step 1, the ZSM-5 molecular sieve of the present invention is a NaZSM-5 molecular sieve, and the basic compound of the present invention is a conventional basic compound in the art, which can be an organic base or an inorganic base, preferably one or more of NaOH, Na2CO3, NaHCO3, and NaAlO2. The basic compound is calculated as an oxide, and the weight ratio of the ZSM-5 molecular sieve to the basic compound is 1:0.08-0.5. When one or more of the preferred NaOH, Na2CO3, NaHCO3, and NaAlO2 are used, the basic compound is calculated as Na2O, and the weight ratio of the ZSM-5 molecular sieve to the basic compound is 1:0.08-0.5.

[0048] In another embodiment, in step 1, the ZSM-5 molecular sieve, the alkaline compound and water are mixed and stirred at a temperature of 40-100° C. and a stirring time of 0.5-5 h.

[0049] In one embodiment, the alkali-modified ZSM-5 molecular sieve is subjected to sodium reduction treatment by exchanging with ammonium salt, that is, the alkali-modified ZSM-5 molecular sieve is mixed with water for slurrying, and then the ammonium salt is added, filtered, and washed. The sodium-reduced ZSM-5 molecular sieve is then mixed with an acidic solution and a zinc-containing compound and stirred.

[0050] The present invention does not specifically limit the ammonium salt. In one embodiment, the ammonium salt is one or more of ammonium sulfate, ammonium chloride, ammonium nitrate, and ammonium phosphate. The present invention does not specifically limit the ion exchange method between the alkali-modified ZSM-5 molecular sieve and the ammonium salt. Conventional ion exchange methods in the art can be used.

[0051] The acidic solution of the present invention can be an inorganic acid solution or an organic acid solution, preferably a hydrochloric acid solution. The concentration of the acidic solution is 0.1-4 mol / L, preferably 0.2-2 mol / L, and the mass ratio of the acidic solution to the ZSM-5 molecular sieve is 2-10. The zinc-containing compound of the present invention refers to a water-soluble zinc-containing salt, which can be derived from one or more of zinc nitrate, zinc chloride, and zinc acetate. The zinc-containing compound is calculated as zinc oxide, and the mass ratio of the zinc-containing compound to the ZSM-5 molecular sieve is 0.1%-2%.

[0052] In one embodiment, the temperature for stirring the ZSM-5 molecular sieve after sodium reduction and the zinc-containing compound is 40-100° C., and the stirring time is 0.3-3 h.

[0053] Step 3 is: mixing the slurry obtained in step 2 with the phosphorus-containing compound, stirring at a temperature of 120-180° C., and reacting for 0.2-3 hours.

[0054] In one embodiment, the phosphorus-containing compound is a compound containing phosphate, such as phosphoric acid or phosphate, and further, phosphoric acid, ammonium phosphate, diammonium phosphate, ammonium hydrogen phosphate and other substances containing phosphate. The phosphorus-containing compound is calculated as phosphorus pentoxide, and the mass ratio of the phosphorus-containing compound to the molecular sieve is 2%-8%.

[0055] In step 4 of the present invention, the drying temperature in the preparation of the modified ZSM-5 molecular sieve is 100-120° C., the calcination temperature is 400-700° C., and the calcination time is 0.5-4 h.

[0056] The modified ZSM-5 molecular sieve of the present invention includes alkali treatment and phosphorus and zinc composite modification. The present invention first performs alkali treatment on the ZSM-5 molecular sieve to remove part of the silicon species and improve the pore structure. After the alkali-treated ZSM-5 molecular sieve is exchanged and sodium-reduced, it is first stirred and exchanged with zinc element for a certain time under acidic medium conditions, and then a phosphorus-containing solution is introduced to further act with the ZSM-5 molecular sieve at a certain temperature, and a modified ZSM-5 molecular sieve with high propylene selectivity is obtained through one-step drying and roasting. In the present invention, ZSM-5 is firstly subjected to alkali treatment to form a rich mesoporous structure, and zinc exchange under acidic medium can remove part of the skeleton aluminum in the ZSM-5 molecular sieve and the fragmented aluminum in the pores, further optimize the pores and acid distribution, form more defect sites, and promote the dispersion of zinc element through the interaction between zinc element and defect sites. Exchange under acidic medium can also avoid the reaction of zinc and phosphorus elements to form zinc phosphate precipitation, and reduce the interaction between zinc phosphate and molecular sieve. During the modification process, zinc and phosphorus are added step by step. The zinc element is added first, which can promote the dispersion of the zinc element on the molecular sieve and strengthen the interaction between the zinc element and the molecular sieve. After the zinc exchange is completed, the high-temperature phosphorus modification is carried out, which reduces the interaction between phosphorus and zinc, and reduces the interference between the interaction between the two elements and the molecular sieve when phosphorus and zinc are added at the same time, so as to achieve the high dispersion of the zinc element and the effective effect of phosphorus, zinc and molecular sieve. At the same time, the zinc and phosphorus modification can be realized in a reaction system, which simplifies the modification process. The modified ZSM-5 molecular sieve of the present invention solves the problem of long process and high energy consumption caused by the separate impregnation and roasting of phosphorus and zinc during the composite modification of phosphorus and zinc on the one hand; on the other hand, it solves the problem that the reaction performance of the ZSM-5 molecular sieve needs to be further improved when phosphorus and zinc are added at the same time in the existing report. The modified ZSM-5 molecular sieve of the present invention is used as a catalytic cracking adjuvant, and then applied to the catalytic cracking process, which can effectively improve the yield of liquefied gas and increase the propylene concentration in the liquefied gas.

[0057] The preparation method of the catalyst aid for catalytic cracking of the present invention can be as follows: adding modified ZSM-5 molecular sieve, inorganic binder, phosphorus-containing compound and clay into water to form slurry, stirring evenly, forming and drying, and calcining to obtain the catalyst aid for catalytic cracking.

[0058] In one embodiment, forming and drying refers to the granulation forming and drying of the catalyst promoter, which is a technology well known to those skilled in the art. The preparation of catalytic cracking catalyst promoter generally uses spray forming and drying, and its process conditions are that the furnace temperature of the spray tower is controlled at 450-550° C. and the spray tail gas temperature is controlled at 150-300° C. After forming and drying, the roasting temperature is 400-700° C. and the roasting time is 0.5-3h.

[0059] The catalytic cracking catalyst aid of the present invention is used in the catalytic cracking process of oil products to increase the yield of liquefied gas and propylene.

[0060] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0061] Analytical methods

[0062] The modified ZSM-5 molecular sieve was characterized by Rigaku D / Max-3C XRD diffractometer. The contents of zinc oxide and phosphorus pentoxide in the modified ZSM-5 molecular sieve were determined by X-ray fluorescence spectrometry (XRF).

[0063] The reaction performance of the catalyst was evaluated by the ACE evaluation device of Kayser Company of the United States. The reaction temperature was 530°C and the catalyst-oil mass ratio was 5.0. Before the evaluation, the catalyst was aged at 800°C with 100% steam for 17 hours. The properties of the raw oil are shown in Table 1. Then, the reaction was compounded with the balance agent LZR-20 provided by Lanzhou Petrochemical Catalyst Plant for evaluation. The compounding ratio was based on the mass ratio, catalyst: LZR-20 = 5:95.

[0064] Table 1 Raw oil properties

[0065]

[0066]

[0067] Source of raw materials

[0068] 1. NaZSM-5 molecular sieve, SiO2 / Al2O3=30, provided by the Catalyst Plant of PetroChina Lanzhou Petrochemical Company;

[0069] 2.NaOH, Na2CO3, NaAlO2, reagents from China National Pharmaceutical Group;

[0070] 3. Zinc chloride, zinc nitrate, zinc acetate, reagents from China National Pharmaceutical Group;

[0071] 4. Hydrochloric acid, Sinopharm reagent;

[0072] 5. Phosphoric acid, ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, China National Pharmaceutical Group reagents;

[0073] 6. Kaolin, produced by China Kaolin Corporation;

[0074] 7. Alumina sol, silica sol, USY, provided by the Catalyst Plant of Lanzhou Petrochemical Company of PetroChina.

[0075] Example 1

[0076] Take 500g NaZSM-5 molecular sieve (dry basis, the same below), add 4000g water, add 200g NaCO3 under stirring, heat to 50°C, continue stirring for 3h, filter, wash and dry the sample after the reaction. Then add the alkali-modified sample to the exchange container, add 8 times the weight of deionized water, then add NH4Cl according to 70% of the weight ratio of the alkali-modified sample, stir at 70°C for 1.5h, filter, wash, repeat the above exchange and sodium reduction steps again and dry to obtain the alkali-modified HZSM-5 molecular sieve.

[0077] Take 2100ml 0.4mol / L hydrochloric acid solution, add 19.8g Zn(NO3)2.6H2O, stir evenly, and after it is completely dissolved, add 300g alkali-modified HZSM-5 molecular sieve (dry basis, the same below), heat to 83℃, and stir for 2.6h. Then add 18.87g (NH4)3PO4, stir evenly, and after it is completely dissolved, heat to 147℃, stir for 2.3h, filter, dry at 106℃ for 33h, and then calcine at 470℃ for 1.4h to obtain zinc and phosphorus composite modified ZSM-5 molecular sieve sample AZP-1. XRF shows that AZP-1 contains 1.8wt% ZnO and 3.0wt% P2O5.

[0078] 750 g of deionized water, 33.3 g of pseudo-boehmite (dry basis, the same below), and 366.7 g of kaolin (dry basis, the same below) were stirred evenly, 8 ml of concentrated hydrochloric acid was added, and after stirring for 30 minutes, 54 g of phosphoric acid was added. After homogenization, 200 g of AZP-1 molecular sieve (dry basis, the same below) was added, and after stirring evenly, 176 g of aluminum sol (solid content, 18.98 wt%) was added. The mixture was slurried evenly, spray-dried to form, and calcined at 500°C for 0.6 h to obtain a catalytic cracking aid CP-1.

[0079] Example 2

[0080] Take 500g NaZSM-5 molecular sieve, add 1000g water, add 60g NaOH under stirring, heat to 85℃, continue stirring for 2h, filter, wash and dry the sample after the reaction. Then add the alkali-modified sample to the exchange container, add 5 times the weight of deionized water, then add NH4SO4 according to 60% of the weight ratio of the alkali-modified sample, stir at 90℃ for 0.5h, filter, wash, repeat the above exchange and sodium reduction steps again and dry to obtain the alkali-modified HZSM-5 molecular sieve.

[0081] Take 630ml of 1.8mol / L hydrochloric acid solution, add 1.50g ZnCl2, stir evenly, and after it is completely dissolved, add 300g of the above-mentioned alkali-modified HZSM-5 molecular sieve, heat to 57°C, stir for 2.1h, then add 30.63g NH4H2PO4, stir evenly, and after it is completely dissolved, heat to 128°C, stir for 2.7h, filter, dry at 103°C for 30h, and then calcine at 530°C for 2.2h to obtain a zinc and phosphorus composite modified ZSM-5 molecular sieve sample AZP-2. XRF shows that AZP-2 contains 0.3wt% ZnO and 6.3wt% P2O5.

[0082] 500 g of deionized water, 16 g of pseudo-boehmite, and 104 g of kaolin were stirred evenly, and 5 ml of concentrated hydrochloric acid was added. After stirring for 30 minutes, 65 g of phosphoric acid was added. After homogenization, 200 g of AZP-2 molecular sieve was added. After stirring evenly, 133 g of silica sol (SiO2 content, 30%) was added. The mixture was slurried evenly, spray-dried to form, and calcined at 450°C for 1.5 h to obtain catalytic cracking aid CP-2.

[0083] Example 3

[0084] Take 500g NaZSM-5 molecular sieve, add 3000g water, add 100g NaCO3 and 187.5g NaAlO2 under stirring, heat to 55℃, continue stirring for 1.5h, filter, wash and dry the sample after the reaction. Then add the alkali-modified sample to the exchange container, add 7 times the weight of deionized water, then add NH4NO3 according to 65% of the weight ratio of the alkali-modified sample, stir at 85℃ for 1.0h, filter, wash, repeat the above exchange and sodium reduction steps again and dry to obtain the alkali-modified HZSM-5 molecular sieve.

[0085] Take 1110ml of 1.3mol / L hydrochloric acid solution, add 4.05g (CH3COO)2Zn, stir evenly, and after it is completely dissolved, add 300g alkali-modified HZSM-5 molecular sieve, heat to 72℃, stir for 0.9h, then add 29.55g (NH4)3PO4, stir evenly, and after it is completely dissolved, heat to 159℃, stir for 1.6h, filter, dry at 119℃ for 20h, and then calcine at 550℃ for 2.0h to obtain zinc and phosphorus composite modified ZSM-5 molecular sieve sample AZP-3. XRF shows that AZP-3 contains 0.6wt% ZnO and 4.7wt% P2O5.

[0086] 600 g of deionized water and 190 g of kaolin were stirred evenly. After stirring for 30 minutes, 122 g of phosphoric acid was added. After homogenization, 200 g of AZP-3 molecular sieve was added. After stirring evenly, 184 g of aluminum sol was added. The mixture was slurried evenly, spray-dried and formed, and calcined at 520° C. for 1.0 h to obtain a catalytic cracking aid CP-3.

[0087] in, Figure 1 The XRD spectrum of the modified ZSM-5 prepared in Example 3 is shown in FIG. Figure 1 As shown, the modified ZSM-5 molecular sieve still has a high diffraction peak intensity, indicating that the modification has no significant effect on the crystal structure of the ZSM-5 molecular sieve.

[0088] Example 4

[0089] Take 500g NaZSM-5 molecular sieve, add 1500g water, add 25g NaOH and 212g NaAlO2 under stirring, heat to 70℃, continue stirring for 4.0h, filter, wash and dry the sample after the reaction. Then add the alkali-modified sample to the exchange container, add 8 times the weight of deionized water, then add NH4NO3 according to 55% of the weight ratio of the alkali-modified sample, stir at 75℃ for 2h, filter, wash, repeat the above exchange and sodium reduction steps again and dry to obtain the alkali-modified HZSM-5 molecular sieve.

[0090] Take 1380ml of 1.5mol / L hydrochloric acid solution, add 16.44g Zn(NO3)2.6H2O, stir evenly, and after it is completely dissolved, add 300g alkali-modified HZSM-5 molecular sieve, heat to 64℃, stir for 0.5h, then add 35.07g H3PO4, stir evenly, and after it is completely dissolved, heat to 166℃, stir for 1.1h, filter, dry at 111℃ for 27h, and then calcine at 590℃ for 1.7h to obtain zinc and phosphorus composite modified ZSM-5 molecular sieve sample AZP-4. XRF shows that AZP-4 contains 1.5wt% ZnO and 7.2wt% P2O5.

[0091] 640g of deionized water, 36.4g of kaolin and 25.5g of pseudo-boehmite were stirred evenly, 10ml of concentrated hydrochloric acid was added, and after stirring for 30 minutes, 106g of phosphoric acid was added, and after homogenization, 200g of AZP-4 molecular sieve was added, and after stirring evenly, 192g of aluminum sol was added, the mixture was slurried evenly, spray-dried and formed, and calcined at 630°C for 1.2h to obtain catalytic cracking aid CP-4.

[0092] Example 5

[0093] Take 500g NaZSM-5 molecular sieve, add 2500g water, add 50g NaCO3 and 225g NaAlO2 under stirring, heat to 60℃, continue stirring for 1.0h, filter, wash and dry the sample after the reaction. Then add the alkali-modified sample to the exchange container, add 6 times the weight of deionized water, then add NH4NO3 according to 80% of the weight ratio of the alkali-modified sample, stir at 80℃ for 1.8h, filter, wash, repeat the above exchange and sodium reduction steps again and dry to obtain the alkali-modified HZSM-5 molecular sieve.

[0094] Take 1740ml 0.8mol / L hydrochloric acid solution, add 5.49g ZnCl2, stir evenly, and after it is completely dissolved, add 300g alkali-modified HZSM-5 molecular sieve, heat to 93℃, stir for 1.6h, then add 27.21g NH4H2PO4, stir evenly, and after it is completely dissolved, heat to 173℃, stir for 0.5h, filter, dry at 116℃ for 24h, and then calcine at 650℃ for 0.9h to obtain zinc and phosphorus composite modified ZSM-5 molecular sieve sample AZP-5. XRF shows that AZP-5 contains 1.1wt% ZnO and 5.6wt% P2O5.

[0095] 700 g of deionized water, 26.7 g of pseudo-boehmite, and 137.8 g of kaolin were stirred evenly, and 7 ml of concentrated hydrochloric acid was added. After stirring for 30 minutes, 87 g of phosphoric acid was added. After homogenization, 200 g of AZP-5 molecular sieve was added. After stirring evenly, 89 g of silica sol was added. The mixture was slurried evenly, spray-dried to form, and calcined at 600 ° C for 1.8 hours to obtain a catalytic cracking aid CP-5.

[0096] Comparative Example 1

[0097] Add the NaZSM-5 sample to the exchange container, add 7 times the weight of deionized water, then add NH4NO3 at 65% of the weight ratio of NaZSM-5, stir at 85°C for 1.0h, filter, wash, repeat the above exchange and sodium reduction steps again and dry to obtain HZSM-5 molecular sieve.

[0098] 600 g of deionized water and 190 g of kaolin were stirred evenly. After stirring for 30 minutes, 122 g of phosphoric acid was added. After homogenization, 200 g of HZSM-5 molecular sieve was added. After stirring evenly, 184 g of aluminum sol was added. The mixture was slurried evenly, spray-dried and formed, and calcined at 520° C. for 1.0 h to obtain a catalytic cracking aid CPD-1.

[0099] Comparative Example 2

[0100] The modified ZSM-5 molecular sieve was prepared according to CN103816936B. The NaZSM-5 sample was added to the exchange container, 7 times the weight of deionized water was added, and then NH4NO3 was added according to 65% of the weight ratio of NaZSM-5, stirred at 85°C for 1.0h, filtered, washed, and the above exchange and sodium reduction steps were repeated again and dried to obtain the HZSM-5 molecular sieve.

[0101] Take 1110ml of deionized water, add 4.05g (CH3COO)2Zn, 29.55g (NH4)3PO4, stir evenly, and after complete dissolution, add 300g HZSM-5 molecular sieve, heat to 159℃, stir for 1.6h, filter, dry at 119℃ for 20h, and then calcine at 550℃ for 2.0h to obtain zinc and phosphorus composite modified ZSM-5 molecular sieve sample AZPD-1. XRF shows that AZPD-1 contains 0.6wt% ZnO and 4.7wt% P2O5.

[0102] 600g of deionized water and 190g of kaolin were stirred evenly. After stirring for 30 minutes, 122g of phosphoric acid was added. After homogenization, 200g of AZPD-1 molecular sieve was added. After stirring evenly, 184g of aluminum sol was added. The mixture was slurried evenly, spray-dried and formed, and calcined at 520°C for 1.0h to obtain catalytic cracking aid CPD-2.

[0103] Comparative Example 3

[0104] The modified ZSM-5 molecular sieve was prepared according to CN101440302B. The NaZSM-5 sample was added to the exchange container, 7 times the weight of deionized water was added, and then NH4NO3 was added according to 65% of the weight ratio of NaZSM-5, stirred at 85°C for 1.0h, filtered, washed, and the above exchange and sodium reduction steps were repeated again and dried to obtain the HZSM-5 molecular sieve.

[0105] Take 1110ml of deionized water, add 4.05g (CH3COO)2Zn, (NH4)3PO4 29.55g, stir evenly, and after complete dissolution, add 200g HZSM-5 molecular sieve, dry at 119℃ for 20h, and then calcine at 550℃ for 2.0h to obtain zinc and phosphorus composite modified ZSM-5 molecular sieve sample AZPD-2. XRF shows that AZPD-2 contains 0.6wt% ZnO and 4.7wt% P2O5. .

[0106] 600g deionized water and 190g kaolin were stirred evenly for 30 minutes, and then 122g phosphoric acid was added. After homogenization, 200g A ZPD-2 molecular sieve, after stirring evenly, add 184g of aluminum sol, slurry evenly, spray dry to form, and calcine at 520℃ for 1.0h to obtain catalytic cracking aid CPD-3.

[0107] Comparative Example 4

[0108] Take 500g NaZSM-5 molecular sieve, add 3000g water, add 100g NaCO3 and 187.5g NaAlO2 under stirring, heat to 55℃, continue stirring for 1.5h, filter, wash and dry the sample after the reaction. Then add the alkali-modified sample to the exchange container, add 7 times the weight of deionized water, then add NH4NO3 according to 65% of the weight ratio of the alkali-modified sample, stir at 85℃ for 1.0h, filter, wash, repeat the above exchange and sodium reduction steps again and dry to obtain the alkali-modified molecular sieve AZM.

[0109] 600 g of deionized water and 190 g of kaolin were stirred evenly. After stirring for 30 minutes, 122 g of phosphoric acid was added. After homogenization, 200 g of alkali-modified HZSM-5 molecular sieve was added. After stirring evenly, 184 g of aluminum sol was added. The mixture was slurried evenly, spray-dried and formed, and calcined at 520° C. for 1.0 h to obtain a catalytic cracking aid CPD-4.

[0110] Comparative Example 5

[0111] Take 500g NaZSM-5 molecular sieve, add 3000g water, add 100g NaCO3 and 187.5g NaAlO2 under stirring, heat to 55℃, continue stirring for 1.5h, filter, wash and dry the sample after the reaction. Then add the alkali-modified sample to the exchange container, add 7 times the weight of deionized water, then add NH4NO3 according to 65% of the weight ratio of the alkali-modified sample, stir at 85℃ for 1.0h, filter, wash, repeat the above exchange and sodium reduction steps again and dry to obtain the alkali-modified HZSM-5 molecular sieve.

[0112] Take 1110ml of 1.3mol / L hydrochloric acid solution, add 4.05g (CH3COO)2Zn, stir evenly, and after it is completely dissolved, add 29.55g (NH4)3PO4, stir evenly, and after it is completely dissolved, add 300g alkali-modified HZSM-5 molecular sieve, heat to 159℃, stir for 1.6h, filter, dry at 119℃ for 20h, and then calcine at 550℃ for 2.0h to obtain zinc and phosphorus composite modified ZSM-5 molecular sieve sample AZPD-3. XRF shows that AZPD-3 contains 0.6wt% ZnO and 4.7wt% P2O5.

[0113] 600g of deionized water and 190g of kaolin were stirred evenly. After stirring for 30 minutes, 122g of phosphoric acid was added. After homogenization, 200g of AZPD-3 molecular sieve was added. After stirring evenly, 184g of aluminum sol was added. The mixture was slurried evenly, spray-dried and formed, and calcined at 520°C for 1.0h to obtain catalytic cracking aid CPD-5.

[0114] Comparative Example 6

[0115] Take 500g NaZSM-5 molecular sieve, add 3000g water, add 100g NaCO3 and 187.5g NaAlO2 under stirring, heat to 55℃, continue stirring for 1.5h, filter, wash and dry the sample after the reaction. Then add the alkali-modified sample to the exchange container, add 7 times the weight of deionized water, then add NH4NO3 according to 65% of the weight ratio of the alkali-modified sample, stir at 85℃ for 1.0h, filter, wash, repeat the above exchange and sodium reduction steps again and dry to obtain the alkali-modified HZSM-5 molecular sieve.

[0116] Take 1110ml of 1.3mol / L hydrochloric acid solution, then add 29.55g of (NH4)3PO4, stir evenly, and after it is completely dissolved, add 300g of alkali-modified HZSM-5 molecular sieve, heat to 159℃, stir for 1.6h, after the reactor is depressurized and cooled, then add 4.05g of (CH3COO)2Zn, stir evenly, after it is completely dissolved, heat to 159℃, stir for 1.6h, filter, dry at 119℃ for 20h, and then calcine at 550℃ for 2.0h to obtain zinc and phosphorus composite modified ZSM-5 molecular sieve sample AZPD-4. XRF shows that AZPD-4 contains 0.05wt% ZnO and 4.7wt% P2O5.

[0117] There is very little ZnO on the AZPD-4 molecular sieve, indicating that a large amount of ZnO is lost when this solution is adopted.

[0118] Table 2 Pore structure data of modified ZSM-5 molecular sieve

[0119]

[0120] The reaction performance evaluation of the catalyst promoters of the embodiments of the present invention and the catalyst promoters of the comparative examples is shown in Table 3, wherein the catalyst promoters of the embodiments and the comparative examples were evaluated after being compounded with LZR-20.

[0121]

[0122] The effects of the catalyst promoter of the present application are: (1) phosphorus and zinc modification will affect the stability and acidity distribution of ZSM-5 molecular sieve. (2) The presence of medium and large pores in the modified ZSM-5 molecular sieve is conducive to the rapid diffusion of oil and gas molecules and reduces the occurrence of secondary reactions.

[0123] From the ACE evaluation results of the catalyst promoters of the embodiment and the comparative example, it can be seen that when the catalyst promoter and the balance agent are compounded at a mass ratio of 5%, the liquefied gas yield and the propylene yield of the catalyst promoter of the present invention are significantly improved compared with the catalyst promoter of the comparative example, showing excellent propylene production performance.

[0124] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a catalyst promoter for catalytic cracking, characterized in that: The catalyst promoter comprises a modified ZSM-5 molecular sieve, a phosphorus-containing compound and a binder, and the preparation method of the modified ZSM-5 molecular sieve comprises: Step 1, mixing ZSM-5 molecular sieve, a basic compound and water, stirring and filtering to obtain a base-modified ZSM-5 molecular sieve; Step 2, mixing the base-modified ZSM-5 molecular sieve, the acidic solution and the zinc-containing compound, and stirring; Step 3, mixing the slurry obtained in step 2 with the phosphorus-containing compound and stirring; Step 4, filtering, drying and calcining the slurry obtained in step 3 to obtain a modified ZSM-5 molecular sieve.

2. The method for preparing a catalyst promoter for catalytic cracking according to claim 1, characterized in that: Step 2 also includes the step of exchanging the alkali-modified ZSM-5 molecular sieve with an ammonium salt, and then mixing and slurrying with an acidic solution.

3. The method for preparing a catalyst promoter for catalytic cracking according to claim 1, characterized in that: The alkaline compound is an inorganic base or an organic base, the alkaline compound is calculated as an oxide, and the weight ratio of the ZSM-5 molecular sieve to the alkaline compound is 1:0.08-0.5; the ZSM-5 molecular sieve and the alkaline compound are stirred at a temperature of 40-100° C. and a stirring time of 0.5-5 h.

4. The method for preparing a catalyst aid for catalytic cracking according to claim 2, characterized in that: The ammonium salt is one or more of ammonium sulfate, ammonium chloride, ammonium nitrate and ammonium phosphate.

5. The method for preparing a catalyst promoter for catalytic cracking according to claim 1, characterized in that: The acidic solution is an organic acid solution or an inorganic acid solution, and the concentration of the acidic solution is 0.1-4 mol / L; the zinc-containing compound is a water-soluble zinc-containing salt, and the zinc-containing compound is calculated as zinc oxide, and the mass ratio of the zinc-containing compound to the ZSM-5 molecular sieve is 0.1%-2%.

6. The method for preparing a catalyst promoter for catalytic cracking according to claim 1, characterized in that: Step 2: The temperature for stirring the alkali-modified ZSM-5 molecular sieve and the zinc-containing compound is 40-100° C. and the stirring time is 0.3-3 h.

7. The method for preparing a catalyst promoter for catalytic cracking according to claim 1, characterized in that: The phosphorus-containing compound is phosphoric acid or phosphate, the phosphorus-containing compound is calculated as phosphorus pentoxide, and the mass ratio of the phosphorus-containing compound to the ZSM-5 molecular sieve is 2%-8%.

8. The method for preparing a catalyst promoter for catalytic cracking according to claim 1, characterized in that: The slurry obtained in step 2 is stirred with the phosphorus-containing compound at a temperature of 120-180° C. and a stirring time of 0.2-3 h.

9. The method for preparing a catalyst promoter for catalytic cracking according to claim 1, characterized in that: In step 4, the drying temperature is 100-120° C., the roasting temperature is 400-700° C., and the roasting time is 0.5-4 h.

10. The catalyst promoter prepared by the preparation method according to any one of claims 1 to 9, characterized in that: Based on the total mass of the modified ZSM-5 molecular sieve, the content of zinc oxide in the modified ZSM-5 molecular sieve is 0.1%-2%, and the content of phosphorus pentoxide is 2%-8%.

11. The catalyst promoter according to claim 10, characterized in that Based on the total dry weight of the catalyst promoter, the content of the modified ZSM-5 molecular sieve is 20%-60%, the content of the phosphorus-containing compound is 2%-20%, and the content of the binder is 2%-20%; or, the catalyst promoter further includes clay.

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