Catalytic cracking aid for increasing yield of propylene as well as preparation method and application of catalytic cracking aid

Abstract

The invention provides a catalytic cracking aid for increasing the yield of propylene as well as a preparation method and application of the catalytic cracking aid. The main active ingredient of the catalytic cracking aid for increasing the yield of propylene is a ZSM-5 molecular sieve; the volume of pores with the pore diameter of 3-20nm on the catalytic cracking aid for increasing the yield of propylene is greater than 0.2 cm < 3 > / g; the pore diameter is in multimodal distribution, and at least one most probable pore diameter is formed between 3 nm and 10 nm. The preparation method of the catalytic cracking aid for increasing the yield of propylene comprises the step of carrying out multi-stage pore treatment on a catalytic cracking aid matrix. The catalytic cracking aid for increasing yield of propylene has many mesopores, the preparation method is simple, the diffusion resistance to diesel oil is small, the cracking capacity is high, and the yield of low-carbon olefins, especially the yield of propylene, can be increased when the catalytic cracking aid is used for preparing low-carbon olefins from petroleum products containing diesel oil and / or gasoline through catalytic cracking.

Description

Technical Field

[0001] The invention belongs to the field of petrochemical industry, and in particular is a propylene production increasing catalytic cracking aid, a preparation method and application thereof. Background Art

[0002] With the continuous development of the oil refining and petrochemical industries, the demand structure of petrochemical products has changed significantly, gasoline and diesel have become oversupplied, and the demand for low-carbon olefins and high-quality gasoline, mainly ethylene and propylene, has increased day by day. Among them, propylene is one of the important chemical raw materials. The traditional production route is mainly obtained through steam cracking. With the strong market demand for products, catalytic cracking technology for producing more propylene has become an important development direction and has also developed rapidly in recent years.

[0003] In addition to cracking catalysts, the catalytic cracking process also uses a variety of auxiliary catalytic cracking additives. These additives can be added to the cracking catalyst to increase the octane number of gasoline, increase the yield of liquefied gas and the propylene concentration in it, promote the conversion of CO to CO2, passivate the toxicity of heavy metal impurities in the raw materials to the catalyst activity, or reduce the SO in the regeneration flue gas. x Among them, the method of increasing propylene production by adding catalytic cracking aids in the catalytic cracking process is widely used because of its advantages of simple operation, flexible reaction and little impact on the whole process. At present, the use of catalysts or aids containing MFI structure zeolites is an effective method for increasing propylene production. The typical representative of zeolites with MFI structure is ZSM-5 zeolite. The basic reaction mechanism of MFI structure zeolites is to selectively crack C6-C12 alkanes and olefins in gasoline fractions to generate C3-C5 olefins, thereby increasing the yield of low-carbon olefins and at the same time increasing the octane number of gasoline.

[0004] Generally speaking, catalytic cracking aids have high activity and strong ability to increase propylene production; the higher the concentration of the aid in the catalyst, the higher the propylene yield. When the concentration of the aid reaches a certain level, the propylene yield will decrease. In order to improve the activity of catalytic cracking aids, technicians in this field have also proposed many effective methods through research. For example, patent application CN114453008A discloses a catalytic cracking aid for increasing the concentration of propylene in liquefied gas and its application. The modified sol prepared by Al2O3, IVB metal oxide and P2O5 is used to modify ZSM-5 zeolite to obtain a ZSM-5 zeolite aid, so that the ZSM-5 zeolite has higher activity and heavy oil cracking ability, and has excellent propylene yield and propylene selectivity.

[0005] However, the pores of ZSM-5 molecular sieve are narrow (about 0.5nm). Due to the limitation of pore size, if the reactant molecules are large, it is difficult for them to enter the pores for reaction, which leads to low effective utilization rate of catalytic cracking aids. Current catalytic cracking aids can only crack part of gasoline or liquefied gas into propylene, while the diesel component produced in the catalytic cracking process is large in size and cannot enter the interior of the catalytic cracking aid, resulting in the inability to crack the diesel. In addition, because the pores of the molecular sieve are narrow, some product molecules are difficult to diffuse out, which easily causes deep dehydrogenation to form coking, promotes the deactivation of the molecular sieve, and thus leads to a short service life of the molecular sieve and a rapid decrease in activity. In the latest research on catalytic cracking aids, some methods for enriching the medium and large pore structure inside the aid are also disclosed.

[0006] For example, patent application CN112387302A discloses a catalytic cracking aid, its preparation method and application, and a method for catalytic cracking of hydrocarbon oil. A certain amount of one-dimensional straight-channel mesoporous silica material is mixed and modified with a high-silicon ZSM-5 hydrogen-type zeolite molecular sieve, and used as the main component of the catalytic cracking aid in a catalytic cracking reaction, which can effectively increase the propylene concentration in the cracking product liquefied gas and increase the octane number of the gasoline product.

[0007] For example, patent application CN111939971A discloses a method for preparing a propylene production-increasing catalytic cracking aid, wherein the HZSM-5 molecular sieve is prepared by exchanging ZSM-5 molecular sieve with hydrochloric acid, and the exchange product is roasted at 550-650°C in water vapor; and then the HZSM-5 molecular sieve is modified by mixing two or more elements of rare earth, phosphorus, magnesium, and zinc to obtain a propylene production-increasing catalytic cracking aid. In the preparation process, the patent uses mixed components as the main raw materials, and the additives are added to interact with the mixed components to effectively adjust the pores of the aid, enrich the medium and large pore structure inside the aid, especially the large pore ratio, and prevent the accumulation of pores.

[0008] However, the above modifications for the multi-stage porosity of catalytic cracking aids are to first modify the ZSM-5 molecular sieve to make it multi-stage porosity, and then mix the molecular sieve with the matrix and the binder to make the catalytic cracking aid or add the modifier to modify it during the molding process of the catalytic cracking aid to make it multi-stage porosity, that is, the pores of the molecular sieve are modified before the catalytic cracking aid is molded. During the molding process, the matrix and the binder will block part of the original pores, and the pores in the obtained catalytic cracking aid are poorly connected, and the effect of reducing the diffusion resistance of macromolecules cannot be achieved. In addition, the preparation cost of the existing catalytic cracking aids that can achieve a higher propylene production increase effect is high, the preparation method is relatively complicated, and in the catalytic cracking process, it is still mainly achieved by promoting the conversion of catalytic gasoline into propylene to achieve the effect of increasing propylene production, and there is almost no cracking promotion effect on diesel and heavy oil. The consumption of diesel has reached its peak in 2016, but there is currently no effective method to solve the difficulty of converting diesel into propylene, so it is urgent to further study and develop new catalytic cracking aids that can promote the conversion and utilization of diesel. Summary of the invention

[0009] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a propylene production-increasing catalytic cracking aid, a preparation method and an application thereof. The propylene production-increasing catalytic cracking aid has many mesopores and a simple preparation method, has a small diffusion resistance to diesel and a strong cracking ability, and can be used for catalytic cracking of petroleum products containing diesel and / or gasoline to increase the yield of light olefins, especially the yield of propylene.

[0010] The purpose of the present invention is achieved through the following technical solutions:

[0011] In a first aspect, the present invention provides a catalytic cracking aid for increasing propylene production, wherein the main active ingredient of the catalytic cracking aid for increasing propylene production is ZSM-5 molecular sieve.

[0012] According to the propylene production increasing catalytic cracking aid of the present invention, the pore volume of the pore size of 3-20nm on the propylene production increasing catalytic cracking aid is greater than 0.2cm 3 / g; the pore size is multimodal, and has at least one most probable pore size between 3-10 nm, preferably at least one most probable pore size between 4-10 nm, more preferably has a first most probable pore size between 4-6 nm, and a second most probable pore size between 6-9 nm.

[0013] In some embodiments of the present invention, the pore volume range of the pore size of 3-20 nm on the propylene production increasing catalytic cracking additive is 0.2-0.4 cm 3 / g; preferably, the pore volume with a pore size of 4-6nm is greater than 0.25cm 3 / g; More preferably, the pore volume with a pore size of 4-8nm is greater than 0.25cm3 / g.

[0014] According to the propylene production increasing catalytic cracking aid of the present invention, the propylene production increasing catalytic cracking aid is obtained by modifying the catalytic cracking aid matrix by desiliconization, dealumination or dealumination-siliconization method to make it multi-level porous.

[0015] According to the propylene production increasing catalytic cracking aid provided by the present invention, the modifier used in the desiliconization method is selected from one or more of sodium hydroxide, potassium hydroxide and calcium hydroxide.

[0016] According to the propylene production increasing catalytic cracking aid provided by the present invention, the modifier used in the dealumination method is selected from at least one of citric acid, hydrochloric acid and nitric acid.

[0017] According to the propylene production increasing catalytic cracking aid provided by the present invention, the modifier used in the dealumination and siliconization method is ammonium hexafluorosilicate.

[0018] The modification is to use a modifier solution to impregnate the catalytic cracking aid matrix, and then filter, dry and roast.

[0019] In some embodiments of the present invention, the concentration of the modifier solution is 0.1-1 mol / L; more preferably, the concentration of the modifier is 0.1-0.8 mol / L, for example 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L.

[0020] In some embodiments of the present invention, the conditions for the impregnation are: solid-liquid ratio of 1:5-1:10 (mass ratio), impregnation temperature of 50-100°C, and impregnation time of 3-12h. More preferably, the conditions for the impregnation are: solid-liquid ratio of 1:6-1:8, impregnation temperature of 60-80°C, and impregnation time of 6-10h.

[0021] In some embodiments of the present invention, the drying temperature is 100-140°C, for example 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C; the drying time is 10-14h, for example 10h, 11h, 12h, 13h, 14h; preferably, the drying temperature is 120°C and the drying time is 12h.

[0022] In some embodiments of the present invention, the calcination temperature is 450-550°C, for example 450°C, 480°C, 500°C, 520°C, 550°C; the calcination time is 4-8h, for example 4h, 5h, 6h, 7h, 8h; preferably, the calcination temperature is 500°C and the calcination time is 6h.

[0023] In a second aspect, the present invention provides a method for preparing a catalytic cracking aid for increasing propylene production, which comprises subjecting a catalytic cracking aid matrix to a multi-stage pore treatment.

[0024] The multi-stage pore treatment is to place the catalytic cracking aid matrix in a modifier solution for immersion modification, and then filter, dry and roast to obtain a multi-stage pore-enhancing propylene catalytic cracking aid.

[0025] In some embodiments of the present invention, the concentration of the modifier solution is 0.1-1 mol / L; more preferably, the concentration of the modifier is 0.1-0.8 mol / L, for example 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L.

[0026] In some embodiments of the present invention, the conditions for the impregnation are: solid-liquid ratio of 1:5-1:10, impregnation temperature of 50-100°C, and impregnation time of 3-12h. More preferably, the conditions for the impregnation are: solid-liquid ratio of 1:6-1:8, impregnation temperature of 60-80°C, and impregnation time of 6-10h.

[0027] In some embodiments of the present invention, the drying temperature is 100-140°C, for example 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C; the drying time is 10-14h, for example 10h, 11h, 12h, 13h, 14h; preferably, the drying temperature is 120°C and the drying time is 12h.

[0028] In some embodiments of the present invention, the calcination temperature is 450-550°C, for example 450°C, 480°C, 500°C, 520°C, 550°C; the calcination time is 4-8h, for example 4h, 5h, 6h, 7h, 8h; preferably, the calcination temperature is 500°C and the calcination time is 6h.

[0029] According to the method for preparing the propylene production increasing catalytic cracking aid provided by the present invention, the multi-stage pore treatment method is selected from any one of a desiliconization method, a dealumination method or a dealumination siliconization method.

[0030] Wherein, the modifier of the desiliconization method is selected from one or more of sodium hydroxide, potassium hydroxide and calcium hydroxide.

[0031] The modifier of the dealumination method is selected from at least one of citric acid, hydrochloric acid and nitric acid.

[0032] The modifier for the dealumination and siliconization method is ammonium hexafluorosilicate.

[0033] The catalytic cracking aid matrix mentioned above is a commercially available catalytic cracking aid having the function of increasing propylene production or a catalytic cracking aid prepared by an existing disclosed catalytic cracking aid preparation method, such as a catalytic cracking aid prepared by any of the methods described in CN 103254925 B, CN102049284 B, CN 104549445 B, CN 102794194 B, etc.

[0034] In a third aspect, the present invention provides use of the propylene yield-increasing catalytic cracking aid of the first aspect or the propylene yield-increasing catalytic cracking aid prepared by the preparation method of the second aspect in catalytic cracking of petroleum products containing diesel and / or gasoline.

[0035] The application is to add the propylene production-increasing catalytic cracking aid of the first aspect or the propylene production-increasing catalytic cracking aid prepared by the preparation method of the second aspect to the catalytic cracking catalyst in an amount of 3-12wt% during the process of catalytic cracking diesel and / or gasoline to produce light olefins; preferably, the light olefin is propylene.

[0036] The beneficial effects of the present invention are as follows:

[0037] The present invention provides a propylene yield-increasing catalytic cracking aid with a ZSM-5 molecular sieve as a main active ingredient. The propylene yield-increasing catalytic cracking aid has many mesopores, small diffusion resistance to diesel, and strong cracking ability. It can be used in the process of catalytic cracking of petroleum products containing diesel and / or gasoline to prepare light olefins, and can increase the yield of light olefins, especially the yield of propylene.

[0038] The present invention utilizes a desiliconization method, a dealumination method or a dealumination siliconization method to modify the catalytic cracking agent matrix, and obtains a catalytic cracking agent for increasing propylene production after multi-stage pore formation. The preparation method is simple and flexible, and a catalytic cracking agent for increasing propylene production with a specific pore size distribution and pore volume range can be quickly obtained, which has better social and economic benefits. Compared with the prior art, by modifying the molecular sieve for multi-stage pore formation before the catalytic cracking agent is formed, the problem of reduced diffusion resistance of macromolecules caused by the original pores being blocked or destroyed during the forming process can be effectively avoided. Moreover, the method of the present invention can be used to post-modify the catalytic cracking aid containing the matrix, molecular sieve and binder components after molding. The modifier not only acts on the molecular sieve in the catalytic cracking aid but also acts on the matrix and binder parts of the catalytic cracking aid, so that the distribution of the mesopores in the modified catalytic cracking aid is more uniform and the newly formed pores can be connected with the original pores, so that the pore connection effect in the entire structural system is better. The multi-level pore system formed by the post-modification method of the present invention makes the diffusion resistance of the diesel component in the aid pores smaller, thereby increasing the diesel cracking ability and increasing the yield of low-carbon olefins while reducing the diesel output. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The pore size analysis results of the catalytic cracking aid matrix and the catalytic cracking aid for increasing propylene production of the present invention are shown in FIG. DETAILED DESCRIPTION

[0040] The following examples further illustrate the technology of the present invention. These examples are for illustration and example of the present invention and are not intended to limit the scope of the present invention in any form.

[0041] Example 1

[0042] 1. Preparation of Catalytic Cracking Auxiliary Agent Matrix

[0043] (1) 4.39 kg of pseudo-boehmite (containing 3 kg of Al2O3) and 5.4 kg of deionized water were slurried for 30 min. 10.3 kg of 85% concentrated phosphoric acid was added to the slurry under stirring, followed by 5.28 kg of 68% concentrated nitric acid. The stirring reaction was continued for 45 min to obtain a colorless and transparent aluminum phosphate sol.

[0044] (2) Add 1.18 kg of water to 1.05 kg (dry basis) of ZSM-5 (SiO2 / Al2O3=50) molecular sieve, homogenize with a shearing machine, then add 65.5 mL of La(NO3)3 solution (La2O3 is 103.13 g / L), stir for 2 h, and prepare a molecular sieve slurry.

[0045] (3) Under stirring, 1775 g of kaolin and 2170 mL of water were mixed and slurried for 30 min, 1.5 kg of phosphate aluminum sol was added to the kaolin slurry, and stirring was continued for 1 h, and then ZSM-5 molecular sieve slurry was added and stirred for 2 h. The solid content of the obtained slurry was 38 wt %. After the slurry was homogenized, it was sprayed to obtain a catalytic cracking propylene additive containing 35 wt % of ZSM-5 molecular sieve.

[0046] 2. Preparation of catalytic cracking additives for increasing propylene production (desiliconization method)

[0047] (1) The catalytic cracking aid matrix obtained above was placed in a sodium hydroxide solution with a concentration of 0.1 mol / L for impregnation modification. The impregnation conditions were: solid-liquid ratio of 1:5, impregnation temperature of 50° C., and impregnation time of 3 h.

[0048] (2) After the impregnation, the solid-liquid separation was carried out, and the solid part was dried and calcined. The drying temperature was 120°C and the drying time was 12 hours. The calcination temperature was 500°C and the calcination time was 6 hours.

[0049] Example 2

[0050] 1. Preparation of Catalytic Cracking Auxiliary Agent Matrix

[0051] (1) 4.39 kg of pseudo-boehmite (containing 3 kg of Al2O3) and 5.4 kg of deionized water were slurried for 30 min. 10.3 kg of 85% concentrated phosphoric acid was added to the slurry under stirring, followed by 5.28 kg of 68% concentrated nitric acid. The stirring reaction was continued for 45 min to obtain a colorless and transparent aluminum phosphate sol.

[0052] (2) Add 1.18 kg of water to 1.05 kg (dry basis) of ZSM-5 (SiO2 / Al2O3=50) molecular sieve, homogenize with a shearing machine, then add 65.5 mL of La(NO3)3 solution (La2O3 is 103.13 g / L), stir for 2 h, and prepare a molecular sieve slurry.

[0053] (3) Under stirring, 1775 g of kaolin and 2170 mL of water were mixed and slurried for 30 min, 1.5 kg of phosphate aluminum sol was added to the kaolin slurry, and stirring was continued for 1 h, and then ZSM-5 molecular sieve slurry was added and stirred for 2 h. The solid content of the obtained slurry was 38 wt %. After the slurry was homogenized, it was sprayed to obtain a catalytic cracking propylene additive containing 35 wt % of ZSM-5 molecular sieve.

[0054] 2. Preparation of catalytic cracking additives for increasing propylene production (desiliconization method)

[0055] (1) The catalytic cracking aid matrix obtained above was placed in a sodium hydroxide solution with a concentration of 0.1 mol / L for impregnation modification. The impregnation conditions were: solid-liquid ratio of 1:5, impregnation temperature of 50° C., and impregnation time of 3 h.

[0056] (2) After the impregnation, the solid-liquid separation was carried out, and the solid part was dried and calcined. The drying temperature was 120°C and the drying time was 12 hours. The calcination temperature was 500°C and the calcination time was 6 hours.

[0057] Example 3

[0058] 1. Preparation of Catalytic Cracking Auxiliary Agent Matrix

[0059] (1) 4.39 kg of pseudo-boehmite (containing 3 kg of Al2O3) and 5.4 kg of deionized water were slurried for 30 min. 10.3 kg of 85% concentrated phosphoric acid was added to the slurry under stirring, followed by 5.28 kg of 68% concentrated nitric acid. The stirring reaction was continued for 45 min to obtain a colorless and transparent aluminum phosphate sol.

[0060] (2) Add 1.18 kg of water to 1.05 kg (dry basis) of ZSM-5 (SiO2 / Al2O3=50) molecular sieve, homogenize with a shearing machine, then add 65.5 mL of La(NO3)3 solution (La2O3 is 103.13 g / L), stir for 2 h, and prepare a molecular sieve slurry.

[0061] (3) Under stirring, 1775 g of kaolin and 2170 mL of water were mixed and slurried for 30 min, 1.5 kg of phosphate aluminum sol was added to the kaolin slurry, and stirring was continued for 1 h, and then ZSM-5 molecular sieve slurry was added and stirred for 2 h. The solid content of the obtained slurry was 38 wt %. After the slurry was homogenized, it was sprayed to obtain a catalytic cracking propylene additive containing 35 wt % of ZSM-5 molecular sieve.

[0062] 2. Preparation of catalytic cracking additives for increasing propylene production (dealuminization method)

[0063] (1) The catalytic cracking aid matrix obtained above was placed in a 0.5 mol / L citric acid solution for impregnation modification. The impregnation conditions were: solid-liquid ratio of 1:10, impregnation temperature of 100° C., and impregnation time of 10 h.

[0064] (2) After the impregnation, the solid-liquid separation was carried out, and the solid part was dried and calcined. The drying temperature was 120°C and the drying time was 12 hours. The calcination temperature was 500°C and the calcination time was 6 hours.

[0065] Example 4

[0066] 1. Preparation of Catalytic Cracking Auxiliary Agent Matrix

[0067] (1) 4.39 kg of pseudo-boehmite (containing 3 kg of Al2O3) and 5.4 kg of deionized water were slurried for 30 min. 10.3 kg of 85% concentrated phosphoric acid was added to the slurry under stirring, followed by 5.28 kg of 68% concentrated nitric acid. The stirring reaction was continued for 45 min to obtain a colorless and transparent aluminum phosphate sol.

[0068] (2) Add 1.18 kg of water to 1.05 kg (dry basis) of ZSM-5 (SiO2 / Al2O3=50) molecular sieve, homogenize with a shearing machine, then add 65.5 mL of La(NO3)3 solution (La2O3 is 103.13 g / L), stir for 2 h, and prepare a molecular sieve slurry.

[0069] (3) Under stirring, 1775 g of kaolin and 2170 mL of water were mixed and slurried for 30 min, 1.5 kg of phosphate aluminum sol was added to the kaolin slurry, and stirring was continued for 1 h, and then ZSM-5 molecular sieve slurry was added and stirred for 2 h. The solid content of the obtained slurry was 38 wt %. After the slurry was homogenized, it was sprayed to obtain a catalytic cracking propylene additive containing 35 wt % of ZSM-5 molecular sieve.

[0070] 2. Preparation of catalytic cracking additives for increasing propylene production (dealuminization and siliconization method)

[0071] (1) The catalytic cracking aid matrix obtained above was placed in a 0.3 mol / L ammonium hexafluorosilicate solution for impregnation modification. The impregnation conditions were: solid-liquid ratio of 1:8, impregnation temperature of 80° C., and impregnation time of 6 h.

[0072] (2) After the impregnation, the solid-liquid separation was carried out, and the solid part was dried and calcined. The drying temperature was 120°C and the drying time was 12 hours. The calcination temperature was 500°C and the calcination time was 6 hours.

[0073] Application Examples

[0074] 1. Physical performance analysis

[0075] The average specific surface area and average pore size of the catalytic cracking aid matrix prepared in Example 4 and the catalytic cracking aid for increasing propylene production prepared in Examples 1-4 were tested and the results are shown in Table 1 below:

[0076] Table 1

[0077]

[0078] The pore size analysis of the catalytic cracking aid matrix and the propylene production increasing catalytic cracking aid prepared in Example 4 yielded Figure 1 .from Figure 1 It can be seen that after the catalytic cracking agent matrix is ​​modified by the dealumination and siliconization method, the propylene production-increasing catalytic cracking agent obtained has significantly more mesopores than the untreated catalytic cracking agent matrix, and the pore volume of the pore size of 3-20nm is greater than 0.2cm 3 / g, with two most probable pore sizes between 4-10 nm, the first most probable pore size at 5.2 nm, and the second most probable pore size at 7.6 nm.

[0079] 2. Catalytic performance analysis

[0080] The catalytic cracking aid matrix prepared in Example 4 and the propylene catalytic cracking aid prepared in Examples 1-4 were added to the catalytic cracking catalyst in an amount of 3%, and the catalytic performance was analyzed using a riser catalytic cracking reaction evaluation device. The riser outlet temperature was 520°C, the catalyst-oil ratio was 1:6, and the reaction pressure was 25 kPa. The results are shown in Table 2 below. As can be seen from Table 2, the use of the propylene catalytic cracking aid of the present invention can promote the conversion of diesel into propylene and liquefied gas.

[0081] Table 2

[0082]

[0083] It should be noted that the above-described embodiments are only used to explain the present invention and do not constitute any limitation of the present invention. The embodiments describe the present invention and it should be understood that the words used therein are descriptive and explanatory words, rather than limiting words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention.

Claims

1. A propylene production increasing catalytic cracking aid, characterized in that: The main active ingredient of the propylene production-increasing catalytic cracking aid is ZSM-5 molecular sieve; the pore volume of the pore size of 3-20nm on the propylene production-increasing catalytic cracking aid is greater than 0.2cm 3 / g; the pore size is multimodal and has at least one most probable pore size between 3-10 nm.

2. The propylene production increasing catalytic cracking aid according to claim 1, characterized in that: The pore volume range of the pore size of the propylene production increasing catalytic cracking additive is 3-20 nm and 0.2-0.4 cm 3 / g; preferably, the pore volume with a pore size of 4-6nm is greater than 0.25cm 3 / g; More preferably, the pore volume with a pore size of 4-8nm is greater than 0.25cm 3 / g.

3. The propylene production increasing catalytic cracking aid according to claim 1 or 2, characterized in that: The catalytic cracking aid for increasing propylene production is obtained by modifying the catalytic cracking aid matrix by using a desiliconization method, a dealumination method or a dealumination and siliconization method to make it multi-level porous.

4. The propylene production increasing catalytic cracking aid according to claim 3, characterized in that: The modifier used in the desiliconization method is selected from one or more of sodium hydroxide, potassium hydroxide and calcium hydroxide; Or, the modifier used in the dealumination method is selected from one or more of citric acid, hydrochloric acid and nitric acid; Alternatively, the modifier used in the dealumination and siliconization method is ammonium hexafluorosilicate.

5. A method for preparing a propylene production increasing catalytic cracking aid as claimed in any one of claims 1 to 4, characterized in that: The preparation method comprises performing multi-stage pore treatment on the catalytic cracking aid matrix.

6. The preparation method according to claim 5, characterized in that: The multi-stage pore treatment is to place the catalytic cracking aid matrix in a modifier solution for immersion modification, and then filter, dry and roast to obtain a multi-stage pore-enhancing propylene catalytic cracking aid.

7. The preparation method according to claim 5 or 6, characterized in that: The multi-stage pore treatment method is selected from any one of a desiliconization method, a dealumination method or a dealumination siliconization method.

8. The preparation method according to claim 6 or 7, characterized in that: The concentration of the modifier solution is 0.1-1 mol / L; and / or The conditions for the impregnation are: solid-liquid ratio of 1:5-1:10, impregnation temperature of 50-100°C, and impregnation time of 3-12h; and / or The drying temperature is 100-140°C and the drying time is 10-14h; and / or The calcination temperature is 450-550° C., and the calcination time is 4-8 hours.

9. Use of the propylene yield-increasing catalytic cracking aid prepared by the preparation method of the propylene yield-increasing catalytic cracking aid as claimed in any one of claims 1 to 4 or the propylene yield-increasing catalytic cracking aid as claimed in any one of claims 5 to 8 in catalytic cracking of petroleum products containing diesel and / or gasoline.

10. The use according to claim 9, characterized in that: The application is in the production of light olefins by catalytic cracking of petroleum products containing diesel and / or gasoline, and preferably the light olefins include propylene.

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