Catalytic cracking metal modified beta molecular sieve catalyst and preparation and application thereof

Abstract

The invention discloses a catalytic cracking metal modified beta molecular sieve catalyst, in the catalyst, the mass ratio of a binder to a beta molecular sieve to a metal oxide is (16-24): (52-68): (12-28), the metal oxide comprises a variable valence metal oxide and an alkali metal oxide, and the alkali metal oxide accounts for 1-25% of the total mass of the metal oxide. The invention also discloses preparation and application of the catalyst. The catalyst is good in catalytic performance, and the preparation method is simple and easy to implement.

Description

Technical Field

[0001] The invention relates to a catalytic cracking metal-modified beta molecular sieve catalyst and its preparation and application. Background Art

[0002] For a long time, ethylene, propylene and butene have been the basic organic chemical raw materials for synthetic resins, synthetic fibers and synthetic rubber. Among them, propylene is an important raw material for the manufacture of petrochemical products second only to ethylene. With the increasing contradiction between the supply and demand of ethylene and propylene, the production of low-carbon olefins has become the goal pursued by many refineries at home and abroad. In the process of petroleum refining and production, a large amount of naphtha with low octane number and difficult to blend before leaving the factory will be produced as a by-product. Therefore, the goal pursued by refineries is to further develop this part of naphtha and efficiently convert it into high value-added products such as ethylene and propylene.

[0003] At present, the main process for producing dienes is still through the steam cracking of petroleum hydrocarbons. About 90% of my country's ethylene, 35% of propylene and 20% of butene are produced from naphtha steam cracking. After years of development, the steam cracking process has become very mature, but it still has inherent disadvantages such as high construction cost, high energy consumption of the device, fixed product composition, and high carbon emissions. Catalytic cracking has the advantages of flexible operation, wide source of raw materials, low energy consumption and low production cost, and can effectively control the ratio of propylene to ethylene, which has important practical significance.

[0004] In order to improve the reaction activity of the catalyst, the reaction temperature is relatively high, but the hydrothermal stability of pure molecular sieve catalysts is poor. Although metal oxide catalysts have high hydrothermal stability, their activity is relatively low, and there is still a certain gap from industrial application. The existing naphtha catalytic cracking technology also has the problem of low diene yield and selectivity. Summary of the invention

[0005] In order to further enrich the selection space of catalysts for catalytic cracking to prepare ethylene and propylene, the present invention provides a catalytic cracking metal-modified β molecular sieve catalyst as a catalyst for catalytic cracking of naphtha to prepare ethylene and propylene. The catalyst uses naphtha, which is a by-product in the process of petroleum refining and production and has a low octane number and is difficult to blend before leaving the factory, as a raw material, and uses the metal-modified β molecular sieve catalyst to prepare light olefins. The catalyst has good hydrothermal stability and a simple preparation process, and has a high ethylene and propylene yield and a low methane yield.

[0006] As one aspect of the present invention, it relates to a catalytic cracking metal-modified β molecular sieve catalyst, in which the mass ratio of binder, β molecular sieve and metal oxide is 16-24:52-68:12-28; the metal oxide includes variable-valence metal oxide and alkali metal oxide, wherein the alkali metal oxide accounts for 1-25% of the total mass of the metal oxide, preferably 1-11%.

[0007] The variable-valence metal oxide is an oxide of Zn, Fe, Ga, Ce or Ag, and the alkali metal oxide is an oxide of Mg or K.

[0008] As another aspect of the present invention, it relates to a method for preparing the above-mentioned metal-modified beta molecular sieve catalyst for catalytic cracking, comprising:

[0009] (1): Mixing β molecular sieve with aluminum sol;

[0010] (2): Add soluble salts of metal components;

[0011] (3): Add potassium carbonate, stir until the slurry is uniform, and then spray granulate.

[0012] The method may further include (4): calcining the solid microspheres.

[0013] In the steps (1), (2) and (3), the stirring time is 0.5-3h.

[0014] In the step (4), the calcination is first carried out at 450-600°C for 2-3 hours, and then at 600-750°C for 1-2 hours.

[0015] The catalyst provided by the present invention has suitable catalytic cracking conditions as follows: a reaction temperature of 600-700° C., a residence time of 1-5 s, and a catalyst-oil ratio of 3-10, wherein the catalyst-oil ratio is a weight ratio.

[0016] As another aspect of the present invention, it relates to the use of the above-mentioned metal-modified beta molecular sieve catalyst for catalytic cracking in the catalytic cracking of naphtha to produce ethylene and propylene.

[0017] As another aspect of the present invention, it relates to a process for preparing ethylene and propylene by catalytic cracking of naphtha, using the above-mentioned metal-modified β molecular sieve catalyst for catalytic cracking.

[0018] When the catalyst provided by the invention is applied to catalytic cracking of naphtha to produce ethylene and propylene, it has a higher raw material conversion rate and ethylene and propylene yield.

[0019] The present invention selects a metal-modified beta molecular sieve composite catalyst, which has good hydrothermal stability and a simple preparation process, is suitable for a fluidized bed reactor, is easy to industrially apply, has a higher ethylene and propylene yield, and a lower methane yield.

[0020] The catalyst of the invention has good catalytic performance and a simple and easy preparation method. DETAILED DESCRIPTION

[0021] The inventors disclosed a catalyst for catalytic cracking of naphtha to produce olefins with reference to CN103785472A. According to the weight content of the catalyst, it contains 50% to 90% of P-modified ZSM-5 molecular sieve, 0.1% to 2.0% of rare earth metal oxide and 0.5% to 2.5% of heteropoly acid. The catalyst loading is 3g, the water-oil volume ratio is 1.5, and the mass space velocity is 2h -1 , the total yield of ethylene and propylene is 42.58% at a reaction temperature of 650° C. This method requires the use of P-modified ZSM-5, has a complex process, high cost, and low olefin yield, which cannot meet the inventor's expectations.

[0022] CN103785460A discloses a naphtha catalytic cracking catalyst. The catalyst comprises 15% to 65% of natural minerals, 10% to 30% of oxides, and 25% to 75% of a mixture of ZSM-5 molecular sieve and phosphorus-modified β molecular sieve. -1 , under the condition of reaction temperature of 650°C, the total yield of ethylene and propylene was 24.5%. The total yield of ethylene and propylene of the catalyst was low and could not meet the expectation of the inventor.

[0023] CN102371172A discloses a naphtha catalytic cracking catalyst that can be used in a fluidized bed. The catalyst comprises 15.0-60.0% kaolin, 10.0-30.0% silicon oxide or aluminum oxide, 0.5-15.0% rare earth or alkaline earth metal oxide, and 25.0-70.0% ZSM-5 zeolite synthesized by a directing agent method with a grain size of 200-1000 nm. The catalyst is evaluated on a fluidized bed reactor with a water-to-oil mass ratio of 4 and a mass space velocity of 1 h -1 When the reaction temperature is 650°C, the conversion rate is 42.3% and the total yield of ethylene and propylene is 21.2%. The total yield of ethylene and propylene of the catalyst is low and cannot meet the expectations of the inventors.

[0024] US2013245350A1 discloses a metal oxide catalyst. The catalyst molecular formula is CrZr j A k O x (0.5≤j≤120, 1≤k≤50, A is a transition metal), using light naphtha as raw material, at a reaction temperature of 824°C, the total yield of ethylene and propylene is 45.9%. This catalyst is a metal oxide catalyst, the reaction temperature is high, and the total yield of ethylene and propylene is low, which cannot meet the inventor's expectations.

[0025] US2003109376A1 discloses a 12CaO-7Al 2 O 3The pure calcium aluminum oxide catalyst was prepared. With light naphtha as raw material, the total yield of ethylene and propylene was 43.87% at a reaction temperature of 800°C. The catalyst requires a high reaction temperature, has high operating costs, and has a low total yield of ethylene and propylene, which cannot meet the inventor's expectations.

[0026] CN 101190414 A document discloses a fluidized bed catalyst for catalytic cracking to produce olefins, wherein the catalyst uses a composite molecular sieve or silicon dioxide as a carrier, and a rare earth element, a composition of elements from other groups of the periodic table and phosphorus oxide as a modifier. The reaction is carried out under the condition of a reaction temperature of 580-650°C with a water / oil weight ratio of 0.5-3:1 as a naphtha raw material. The preparation process of the composite molecular sieve requires the addition of a template agent, which is more expensive and causes serious environmental pollution compared to the process of synthesizing ZSM-5 molecular sieves without a commercial template agent. In addition, phosphorus-containing compounds are required in the preparation process of the composite molecular sieve, which will lead to eutrophication and pollution of wastewater bodies. The inventor found that when the catalyst is used, the yield of cracking byproduct methane is as high as 17.08%. The byproduct methane yield is too high and cannot meet the inventor's expectations.

[0027] In view of the fact that the prior art cannot meet the inventor's expectations, the inventor made the present invention after further research and development.

[0028] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0029] Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.

[0030] In the present application, alumina mainly exists in the form of a binder. Therefore, when describing metal oxides in the present application, alumina is not included. The metal oxides described in the present application refer to metal oxides that mainly play a role in metal catalytic activity in the catalyst.

[0031] The multi-metal modified β molecular sieve catalyst prepared in the embodiment was evaluated for performance on a riser pilot plant manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The preparation methods of different catalysts are shown in Examples 1-15, and the evaluation results are shown in Table 2. Thai naphtha was used as the raw material, and the naphtha group composition is shown in Table 1.

[0032] Table 1 Naphtha group composition, wt%

[0033]

[0034] Example 1

[0035] Add 6 kg of β molecular sieve into 10 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0036] Add 5.48 kg zinc nitrate (Zn(NO 3 ) 2 6H 2 O) and 0.5 kg gallium oxide (Ga 2 O 3 ), stir evenly, add 0.05kg potassium carbonate (K 2 CO 3 ) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0037] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0038] In the obtained catalyst, zinc exists in the form of zinc oxide, gallium exists in the form of gallium oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 20:60:20; in the metal oxide, potassium oxide accounts for 2% of the total mass of the metal oxide.

[0039] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this example was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 52.15%, and the methane yield was 9.32%.

[0040] Example 2

[0041] Add 6 kg of β molecular sieve to 8.5 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0042] Add 1.5 kg Zn(NO 3 ) 2 6H 2 O) and 4.05 kg of ferric nitrate (Fe(NO 3 ) 3 9H 2 O), stir evenly, add 0.18kg potassium carbonate (K 2 CO 3 ) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0043] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0044] In the obtained catalyst, zinc exists in the form of zinc oxide, iron exists in the form of iron oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 19:66:15; in the metal oxide, potassium oxide accounts for 9% of the total mass of the metal oxide.

[0045] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this example was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 52.95%, and the methane yield was 9.15%.

[0046] Example 3

[0047] Add 5.5 kg of β molecular sieve to 12.5 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0048] Add 2kg of iron oxide (Fe 2 O 3 ) and 1.26 kg cerium nitrate (Ce(NO 3 ) 3 6H 2 O), stir evenly, add 0.1kg potassium carbonate (K 2 CO 3 ) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0049] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0050] In the obtained catalyst, iron exists in the form of iron oxide, cerium exists in the form of cerium oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 24:52:24; in the metal oxide, potassium oxide accounts for 3% of the total mass of the metal oxide.

[0051] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this embodiment was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 53.59% and the methane yield was 9.07%.

[0052] Example 4

[0053] Add 6 kg of β molecular sieve into 8 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0054] Add 1.5kg zinc oxide (ZnO) and 0.5kg gallium oxide (Ga 2 O 3 ) and 1.91 kg magnesium nitrate (Mg(NO 3 ) 2 6H 2 O), stir evenly, add 0.1kg potassium carbonate (K 2 CO 3 ) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0055] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0056] In the obtained catalyst, zinc exists in the form of zinc oxide, gallium exists in the form of gallium oxide, magnesium exists in the form of magnesium oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 16:59:25; in the metal oxide, the sum of magnesium oxide and potassium oxide accounts for 23% of the total mass of the metal oxide.

[0057] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this example was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 52.66%, and the methane yield was 9.16%.

[0058] Example 5

[0059] Add 6.5 kg of β molecular sieve into 9.5 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0060] Add 1kg zinc oxide (ZnO), 2.03kg iron nitrate and 0.5kg cerium nitrate (Ce(NO 3 ) 3 6H 2 O), stir evenly, add 0.05kg potassium carbonate (K 2 CO 3 ) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0061] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0062] In the obtained catalyst, zinc exists in the form of zinc oxide, iron exists in the form of iron oxide, cerium exists in the form of cerium oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 19:65:16; in the metal oxide, potassium oxide accounts for 2% of the total mass of the metal oxide.

[0063] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this example was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 54.02% and the methane yield was 9.03%.

[0064] Example 6

[0065] Add 6.5 kg of β molecular sieve into 9.5 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0066] Add 1kg zinc oxide (ZnO), 2.02kg ferric nitrate, 1.2kg silver oxide (Ag 2 After stirring evenly, add 0.04 kg potassium carbonate (K 2 CO 3 ) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0067] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0068] In the obtained catalyst, zinc exists in the form of zinc oxide, iron exists in the form of iron oxide, cerium exists in the form of cerium oxide, silver exists in the form of silver oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 17:59:24; in the metal oxide, potassium oxide accounts for 1% of the total mass of the metal oxide.

[0069] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this embodiment was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 54.89% and the methane yield was 8.97%.

[0070] Example 7

[0071] Add 6 kg of β molecular sieve into 10 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0072] Add 4 kg zinc nitrate (Zn(NO 3 ) 2 6H 2 O), 2kg magnesium nitrate (Mg(NO 3 ) 2 6H 2 O), 3kg ferric nitrate (Fe(NO 3 ) 3 9H 2 O) and 0.2 kg cerium oxide (CeO 2 ), 1.0 kg silver nitrate (AgNO 3 ) after stirring evenly, add 0.05kg potassium carbonate (K 2 CO 3 ) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0073] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0074] In the obtained catalyst, zinc exists in the form of zinc oxide, iron exists in the form of iron oxide, cerium exists in the form of cerium oxide, silver exists in the form of silver oxide, magnesium exists in the form of magnesium oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 18:54:28; in the metal oxide, the sum of magnesium oxide and potassium oxide accounts for 19% of the total mass of the metal oxide.

[0075] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this example was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 53.33%, and the methane yield was 9.09%.

[0076] Example 8

[0077] Add 6.5 kg of β molecular sieve into 9.5 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0078] Add 0.05 kg of gallium oxide (Ga 2 O 3 )、1.5kg magnesium nitrate (Mg(NO 3 ) 2 6H 2 O), 1.2 kg silver oxide (Ag 2 O) After stirring evenly, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0079] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0080] In the obtained catalyst, gallium exists in the form of gallium oxide, silver exists in the form of silver oxide, magnesium exists in the form of magnesium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 19:65:16; in the metal oxide, magnesium oxide accounts for 25% of the total mass of the metal oxide.

[0081] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this example was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 53.38%, and the methane yield was 9.12%.

[0082] Example 9

[0083] Add 6.5 kg of β molecular sieve into 9.5 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0084] Add 0.3 kg of cerium nitrate (Ce(NO 3 ) 3 6H 2 O) and 1.0 kg silver nitrate (AgNO 3 ) after stirring evenly, add 0.04kg potassium carbonate (K 2 CO 3 ) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0085] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0086] In the obtained catalyst, cerium exists in the form of cerium oxide, silver exists in the form of silver oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 20:68:16; in the metal oxide, potassium oxide accounts for 25% of the total mass of the metal oxide.

[0087] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this embodiment was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 54%, and the methane yield was 9.06%.

[0088] Example 10

[0089] Add 6 kg of β molecular sieve into 10 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0090] Add 0.5 kg magnesium nitrate (Mg(NO 3 ) 3 6H 2 O), 1 kg ferric nitrate (Fe(NO 3 ) 3 6H 2 O), 0.3 kg cerium nitrate (Ce(NO 3 ) 3 6H 2 O) and 1.1 kg silver oxide (Ag 2 After stirring evenly, add 0.04 kg potassium carbonate (K 2 CO 3 ) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0091] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0092] In the obtained catalyst, magnesium exists in the form of magnesium oxide, iron exists in the form of iron oxide, cerium exists in the form of cerium oxide, silver exists in the form of silver oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 21:63:16; in the metal oxide, the sum of magnesium oxide and potassium oxide accounts for 11% of the total mass of the metal oxide.

[0093] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this example was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 53.54%, and the methane yield was 9.13%.

[0094] Embodiment 11

[0095] Add 7 kg of β molecular sieve into 11 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0096] Add 0.5kg magnesium oxide (MgO), 2kg iron oxide (Fe 2 O 3 ), 0.05kg gallium oxide (Ga 2 O 3 ) and 0.3kg cerium oxide (Ce 2 O 3) and stirred until the slurry was uniform, then 0.01 kg potassium carbonate (K 2 CO 3 ) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0097] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0098] In the obtained catalyst, magnesium exists in the form of magnesium oxide, iron exists in the form of iron oxide, gallium exists in the form of gallium oxide, cerium exists in the form of cerium oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 18:58:24; in the metal oxide, the sum of magnesium oxide and potassium oxide accounts for 18% of the total mass of the metal oxide.

[0099] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this example was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 51.67%, and the methane yield was 9.28%.

[0100] Example 12

[0101] Add 6 kg of β molecular sieve into 10 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0102] Add 2 kg zinc nitrate (Zn(NO 3 ) 2 6H 2 O), 1.5 kg iron oxide (Fe 2 O 3 ), 0.2kg cerium oxide (Ce 2 O 3 ), stir until the slurry is uniform, add 0.08 kg potassium carbonate (K 2 CO 3 ) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0103] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0104] In the obtained catalyst, zinc exists in the form of zinc oxide, iron exists in the form of iron oxide, cerium exists in the form of cerium oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 21:56:23; in the metal oxide, potassium oxide accounts for 3% of the total mass of the metal oxide.

[0105] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this example was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 53.78%, and the methane yield was 9.11%.

[0106] Embodiment 13

[0107] Add 5 kg of β molecular sieve into 12 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0108] Add 1kg zinc oxide (ZnO), 0.05kg gallium oxide (Ga 2 O 3 ), 1.2 kg silver oxide (Ag 2 O), stir until the slurry is uniform, add 0.09 kg potassium oxide (K 2 O) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0109] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0110] In the obtained catalyst, zinc exists in the form of zinc oxide, gallium exists in the form of gallium oxide, silver exists in the form of silver oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 24:53:23; in the metal oxide, potassium oxide accounts for 4% of the total mass of the metal oxide.

[0111] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this example was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 52.99% and the methane yield was 9.16%.

[0112] Embodiment 14

[0113] Add 6 kg of β molecular sieve into 11 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0114] Add 1kg magnesium oxide (MgO), 0.2kg cerium oxide (Ce 2 O 3 ), 1.0 kg silver nitrate (AgNO 3 ), stir until the slurry is uniform, add 0.01kg potassium oxide (K 2 O) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0115] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0116] In the obtained catalyst, magnesium exists in the form of magnesium oxide, cerium exists in the form of cerium oxide, silver exists in the form of silver oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 24:65:12; in the metal oxide, the sum of magnesium oxide and potassium oxide accounts for 19% of the total mass of the metal oxide.

[0117] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this example was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 52.99% and the methane yield was 9.21%.

[0118] Embodiment 15

[0119] Add 7 kg of β molecular sieve into 9 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0120] Add 0.1kg magnesium oxide (MgO), 1kg iron oxide (Fe 2 O 3 ), 0.3kg cerium oxide (Ce 2 O 3 ), 0.5 kg silver nitrate (AgNO 3 ), stir until the slurry is uniform, then add 0.4 kg potassium oxide (K 2 O) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0121] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0122] In the obtained catalyst, magnesium exists in the form of magnesium oxide, iron exists in the form of iron oxide, cerium exists in the form of cerium oxide, silver exists in the form of silver oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 16:64:20; in the metal oxide, the sum of potassium oxide and magnesium oxide accounts for 23% of the total mass of the metal oxide.

[0123] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this example was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 51.01%, and the methane yield was 9.39%.

[0124] Comparative Example 1

[0125] Add 7 kg of β molecular sieve to 7.5 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0126] Add 0.6 kg of gallium oxide (Ga 2 O 3 ) and 5.72 kg magnesium nitrate (Mg(NO 3 ) 2 6H 2 O), stirred until the slurry was uniform, and 0.15 kg of potassium carbonate (K 2 CO 3 ) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0127] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0128] In the obtained catalyst, gallium exists in the form of gallium oxide, magnesium exists in the form of magnesium oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 14:65:21; in the metal oxide, the sum of magnesium oxide and potassium oxide accounts for 74% of the total mass of the metal oxide.

[0129] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this example was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 47.3%, and the methane yield was 12.31%.

[0130] Comparative Example 2

[0131] Add 3 kg of β molecular sieve into 18 kg of aluminum sol (alumina content is 20%), and add appropriate amount of water for slurrying;

[0132] Add 5kg zinc nitrate (Zn(NO 3 ) 2 6H 2 O), 0.5kg iron oxide (Fe 2 O 3 ) and 0.5kg cerium oxide (CeO 2 ), 1.0 kg silver nitrate (AgNO 3 ), stir until the slurry is uniform, then add 0.2 kg potassium oxide (K 2 O) powder, continue stirring until the slurry is uniform, and then spray granulate to obtain solid microspheres.

[0133] The solid microspheres were first calcined at 550°C for 3 h and then at 730°C for 1.5 h to obtain a catalytic cracking catalyst.

[0134] In the obtained catalyst, zinc exists in the form of zinc oxide, iron exists in the form of iron oxide, cerium exists in the form of cerium oxide, silver exists in the form of silver oxide, potassium exists in the form of potassium oxide, and the catalyst uses aluminum oxide as a binder. In the catalyst, the mass ratio of binder: molecular sieve: metal oxide is 37:30:33; in the metal oxide, potassium oxide accounts for 6% of the total mass of the metal oxide.

[0135] Using naphtha as raw material, the performance of the multi-metal modified β molecular sieve catalyst prepared in this example was evaluated on a riser pilot device manufactured by Qingdao Jietian Technology, with a reaction temperature of 700°C and a residence time of 3.5s. The catalyst evaluation results showed that the total yield of ethylene and propylene per pass reached 48.8%, and the methane yield was 12.12%.

[0136] The aluminum oxide content of comparative example 1 is too low, and the alkali metal content is too high, resulting in insufficient acid sites of the catalyst, low olefin yield, and high methane yield; the molecular sieve content of comparative example 2 is too low, and the metal oxide content is too high, resulting in low micropore acid content of the catalyst, excessive hydrocarbon activation, and low olefin yield. Appropriate alkali metals in the catalyst can neutralize excessive acidity, but too much alkali metal will cause insufficient acidity of the catalyst and high methane yield. Other metal oxides except alkali metals have the function of appropriately activating hydrocarbon molecules. For this reason, the catalyst has appropriate molecular sieve content and aluminum oxide content, and appropriate metal oxides that activate hydrocarbons can ensure sufficient reaction performance of the catalyst.

[0137] Table 2 Evaluation results

[0138]

[0139]

[0140] The technical solution of the present application adopts a binder, a transition metal-modified beta molecular sieve and an alkali metal modification, does not use phosphorus-containing compounds, and reduces the discharge of eutrophic wastewater.

Claims

1. A catalytic cracking metal-modified β molecular sieve catalyst, characterized in that: In the catalyst, the mass ratio of the binder, the beta molecular sieve and the metal oxide is 16-24:52-68:12-28, wherein the metal oxide comprises a variable valence metal oxide and an alkali metal oxide, wherein the alkali metal oxide accounts for 1-25% of the total mass of the metal oxide.

2. The catalytic cracking metal-modified β molecular sieve catalyst according to claim 1, characterized in that: The variable-valence metal oxide is an oxide of Zn, Fe, Ga, Ce or Ag, and the alkali metal oxide is an oxide of Mg or K.

3. The catalytic cracking metal-modified β molecular sieve catalyst according to claim 2, characterized in that: In the catalyst, the mass ratio of the binder, the beta molecular sieve and the metal oxide is 18-21:58-64:20-24.

4. The catalytic cracking metal-modified β molecular sieve catalyst according to claim 2, characterized in that: The alkali metal oxide accounts for 1-11% of the total mass of the metal oxide.

5. A method for preparing the metal-modified beta molecular sieve catalyst for catalytic cracking according to any one of claims 1 to 4, characterized in that: include: (1): Mixing β molecular sieve with aluminum sol; (2): Add soluble salts of metal components; (3): Add potassium carbonate, stir until the slurry is uniform, and then spray granulate.

6. The method according to claim 5, characterized in that The method also includes (4): calcining the solid microspheres.

7. The method of claim 5, characterized in that In the steps (1), (2) and (3), the stirring time is 0.5-3h.

8. The method of claim 6, characterized in that In the step (4), the calcination is first carried out at 450-600°C for 2-3 hours, and then at 600-750°C for 1-2 hours.

9. Use of the metal-modified beta molecular sieve catalyst for catalytic cracking according to any one of claims 1 to 4 in the catalytic cracking of naphtha to produce ethylene and propylene.

10. A process for preparing ethylene and propylene by catalytic cracking of naphtha, characterized in that: The metal-modified beta molecular sieve catalyst for catalytic cracking according to any one of claims 1 to 4 is used.

11. The process according to claim 10, characterized in that The catalytic cracking conditions are: reaction temperature 600-700°C, residence time 1-5s, catalyst-oil ratio 3-10.

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