Catalytic cracking metal-modified beta molecular sieve catalysts, their preparation and use

Abstract

The application discloses a catalytic cracking metal modified beta molecular sieve catalyst, and the mass ratio of a binder, a beta molecular sieve and a metal oxide in the catalyst is 16-24:52-68:12-28, wherein 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 application further discloses preparation and application of the catalyst. The catalyst has good catalytic performance and the preparation method is simple and easy to implement.

Description

Technical Field

[0001] This invention relates to a catalyst for catalytic cracking of metal-modified β-zeolite, its preparation, and its application. Background Technology

[0002] For a long time, ethylene, propylene, and butene have been basic organic chemical raw materials for synthetic resins, synthetic fibers, and synthetic rubber. Among them, propylene is the second most important raw material for manufacturing petrochemical products, after ethylene. With the increasing imbalance between the supply and demand of ethylene and propylene, producing more low-carbon olefins has become a goal pursued by many refineries both domestically and internationally. However, in the petroleum refining and production process, a large amount of naphtha with low octane ratings and difficult to blend is produced as a byproduct. Therefore, further development of this naphtha and its efficient conversion into high-value-added products such as ethylene and propylene is a goal pursued by refineries.

[0003] Currently, petroleum hydrocarbon steam cracking remains the primary process for producing dienes. In my country, approximately 90% of ethylene, 35% of propylene, and 20% of butene are produced through naphtha steam cracking. While the steam cracking process has matured over many years, it still suffers from inherent drawbacks such as high construction costs, high energy consumption, fixed product composition, and large carbon emissions. Catalytic cracking, on the other hand, offers advantages such as flexible operation, a wide range of feedstock sources, low energy consumption, and low production costs. It can also effectively control the propylene to ethylene ratio, making it of significant practical importance.

[0004] To improve the catalytic activity, higher reaction temperatures are required, but pure molecular sieve catalysts have poor hydrothermal stability. While metal oxide catalysts offer high hydrothermal stability, their activity is relatively low, dwindling before industrial application. Existing naphtha catalytic cracking technologies also suffer from low diene yields and selectivity. Summary of the Invention

[0005] To further enrich the selection of catalysts for catalytic cracking to produce ethylene and propylene, this invention provides a metal-modified β-zeolite catalyst for catalytic cracking of naphtha to produce ethylene and propylene. This catalyst uses naphtha with low octane number and difficult to blend and finish as a byproduct of petroleum refining and production as raw material. It prepares low-carbon olefins using a metal-modified β-zeolite catalyst, exhibits good hydrothermal stability, has a simple preparation process, and achieves a high ethylene and propylene yield with a low methane yield.

[0006] As one aspect of the present invention, a catalyst for catalytic cracking of metal-modified β-zeolite is provided, wherein the mass ratio of binder, β-zeolite, and metal oxide is 16-24:52-68:12-28; the metal oxide includes variable valence metal oxides and alkali metal oxides, wherein the alkali metal oxide accounts for 1-25% of the total mass of the metal oxides, 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, a method for preparing the above-mentioned metal-modified β-zeolite catalyst for catalytic cracking is provided, comprising:

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

[0010] (2): Add a soluble salt of the metal component;

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

[0012] It may also include (4): calcining the solid microspheres.

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

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

[0015] The catalyst provided by this invention is suitable for catalytic cracking under the following conditions: reaction temperature of 600-700℃, residence time of 1-5s, and catalyst-to-oil ratio of 3-10, wherein the catalyst-to-oil ratio is by weight.

[0016] As another aspect of the present invention, the application of the above-mentioned metal-modified β-zeolite catalyst for catalytic cracking in the catalytic cracking of naphtha to produce ethylene and propylene is discussed.

[0017] As another aspect of the present invention, a process for catalytic cracking of naphtha to produce ethylene and propylene is provided, using the aforementioned metal-modified β-zeolite catalyst for catalytic cracking.

[0018] The catalyst provided by this invention exhibits high feed conversion rate and ethylene-propylene yield when applied to the catalytic cracking of naphtha to produce ethylene-propylene.

[0019] This invention uses a metal-modified β-molecular sieve composite catalyst, which has good hydrothermal stability and a simple preparation process. It is suitable for fluidized bed reactors, easy to industrialize, and has a high ethylene and propylene yield and a low methane yield.

[0020] The catalyst of this invention has good catalytic performance and the preparation method is simple and easy to implement. Detailed Implementation

[0021] The inventors have disclosed a naphtha catalytic cracking catalyst for olefin production, based on CN103785472A. The catalyst, by weight, contains 50%–90% P-modified ZSM-5 molecular sieve, 0.1%–2.0% rare earth metal oxides, and 0.5%–2.5% heteropoly acids. Evaluation was conducted in a microreactor fixed-bed apparatus with a catalyst loading of 3g, a water-to-oil volume ratio of 1.5, and a mass hourly space velocity (H₂S₀) of 2h⁻¹. -1 The total yield of ethylene and propylene was 42.58% at a reaction temperature of 650℃. This method requires the use of P-modified ZSM-5, which is complex, costly, and results in low olefin yields, failing to meet the inventors' expectations.

[0022] CN103785460A discloses a naphtha catalytic cracking catalyst. This catalyst comprises 15%–65% natural minerals, 10%–30% oxides, and a mixture of 25%–75% ZSM-5 molecular sieve and phosphorus-modified β-molecular sieve. At a water-to-oil mass ratio of 4 and a mass hourly space velocity (H₂S / H₂O) of 1 h⁻¹, the catalyst is used in the cracking process. -1 At a reaction temperature of 650℃, the total yield of ethylene and propylene was 24.5%. The total yield of ethylene and propylene using this catalyst was low and did not meet the inventors' expectations.

[0023] CN102371172A discloses a naphtha catalytic cracking catalyst that can be used in a fluidized bed reactor. This catalyst comprises 15.0–60.0% kaolin, 10.0–30.0% silica or alumina, 0.5–15.0% rare earth or alkaline earth metal oxides, and 25.0–70.0% ZSM-5 zeolite with a grain size of 200–1000 nm, synthesized using a directed-directing agent method. Evaluation in a fluidized bed reactor showed good performance at a water-to-oil mass ratio of 4 and a mass hourly space velocity (H₂S) of 1 h₀. -1 At a reaction temperature of 650℃, the conversion rate was 42.3%, and the total yield of ethylene and propylene was 21.2%. The total yield of ethylene and propylene using this catalyst was low and did not meet the inventors' expectations.

[0024] US patent 2013245350A1 discloses a metal oxide catalyst. The catalyst has the molecular formula CrZr. j A k O x (0.5≤j≤120, 1≤k≤50, A is a transition metal), using light naphtha as raw material, the total yield of ethylene and propylene is 45.9% at a reaction temperature of 824℃. This catalyst belongs to the metal oxide catalyst category. At high reaction temperatures, the total yield of ethylene and propylene is relatively low, which does not meet the inventors' expectations.

[0025] US2003109376A1 discloses a pure calcium aluminum ore catalyst of 12CaO-7Al2O3. Using light naphtha as raw material, the total yield of ethylene and propylene is 43.87% at a reaction temperature of 800°C. This catalyst requires a high reaction temperature, has high operating costs, and a low total yield of ethylene and propylene, which does not meet the inventor's expectations.

[0026] CN 101190414 A discloses a fluidized bed catalyst for catalytic cracking to produce olefins. The catalyst uses a composite molecular sieve or silica as a support, and a combination of rare earth elements, elements from other groups of the periodic table, and phosphorus oxides as modifiers. The reaction is carried out using naphtha as feedstock with a water / oil weight ratio of 0.5-3:1 at a reaction temperature of 580-650℃. The preparation process of this composite molecular sieve requires the addition of a template agent, which is more costly and causes severe environmental pollution compared to the commercial template-free synthesis of ZSM-5 molecular sieves. Furthermore, the preparation process of this composite molecular sieve requires the use of phosphorus-containing compounds, leading to eutrophication and pollution of wastewater. The inventors found that the yield of the cracking byproduct methane is as high as 17.08% when using this catalyst. This excessively high methane yield does not meet the inventors' expectations.

[0027] Given that the existing technology could not meet the inventor's expectations, the inventor made this invention after further research and development.

[0028] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

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

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

[0031] The multi-metal modified β-zeolite catalysts prepared in the examples were evaluated for performance on a riser pilot plant manufactured by Qingdao Jietian Technology Co., Ltd. The reaction temperature was 700℃ and the residence time was 3.5 s. The preparation methods for different catalysts are described 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 to 10 kg of aluminum sol (alumina content is 20%), add an appropriate amount of water and slurry.

[0036] Add 5.48 kg of zinc nitrate (Zn(NO3)2·6H2O) and 0.5 kg of gallium oxide (Ga2O3), stir until homogeneous, then add 0.05 kg of potassium carbonate (K2CO3) powder, continue stirring until the slurry is homogeneous, and then perform spray granulation to obtain solid microspheres.

[0037] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

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

[0039] Using naphtha as raw material, the performance of the multi-metal modified β-zeolite catalyst prepared in this example was evaluated on a riser pilot plant manufactured by Qingdao Jietian Technology Co., Ltd. The reaction temperature was 700℃ and the residence time was 3.5 s. The catalyst evaluation results showed that the total single-pass yield of ethylene and propylene 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 alumina sol (alumina content is 20%), add an appropriate amount of water and slurry;

[0042] Add 1.5 kg of Zn(NO3)2·6H2O and 4.05 kg of ferric nitrate (Fe(NO3)3·9H2O), stir evenly, then add 0.18 kg of potassium carbonate (K2CO3) powder, continue stirring until the slurry is uniform, and then perform spray granulation to obtain solid microspheres.

[0043] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

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

[0045] Using naphtha as raw material, the performance of the multi-metal modified β-zeolite catalyst prepared in this example was evaluated on a riser pilot plant manufactured by Qingdao Jietian Technology Co., Ltd. The reaction temperature was 700℃ and the residence time was 3.5 s. The catalyst evaluation results showed that the total single-pass yield of ethylene and propylene 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%), add an appropriate amount of water and slurry.

[0048] Add 2 kg of iron oxide (Fe2O3) and 1.26 kg of cerium nitrate (Ce(NO3)3·6H2O), stir evenly, then add 0.1 kg of potassium carbonate (K2CO3) powder, continue stirring until the slurry is uniform, and then perform spray granulation to obtain solid microspheres.

[0049] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

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

[0051] Using naphtha as raw material, the performance of the multi-metal modified β-zeolite catalyst prepared in this example was evaluated on a riser pilot plant manufactured by Qingdao Jietian Technology Co., Ltd. The reaction temperature was 700℃ and the residence time was 3.5 s. The catalyst evaluation results showed that the single-pass total yield of ethylene and propylene reached 53.59%, and the methane yield was 9.07%.

[0052] Example 4

[0053] Add 6 kg of β molecular sieve to 8 kg of alumina sol (alumina content is 20%), add an appropriate amount of water and slurry.

[0054] Add 1.5 kg of zinc oxide (ZnO), 0.5 kg of gallium oxide (Ga2O3), and 1.91 kg of magnesium nitrate (Mg(NO3)2·6H2O). After stirring evenly, add 0.1 kg of potassium carbonate (K2CO3) powder and continue stirring until the slurry is uniform. Then, perform spray granulation to obtain solid microspheres.

[0055] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

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

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

[0058] Example 5

[0059] Add 6.5 kg of β molecular sieve to 9.5 kg of alumina sol (alumina content is 20%), add an appropriate amount of water and slurry;

[0060] Add 1 kg of zinc oxide (ZnO), 2.03 kg of ferric nitrate and 0.5 kg of cerium nitrate (Ce(NO3)3·6H2O), stir evenly, then add 0.05 kg of potassium carbonate (K2CO3) powder, continue stirring until the slurry is uniform, and then perform spray granulation to obtain solid microspheres.

[0061] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

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

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

[0064] Example 6

[0065] Add 6.5 kg of β molecular sieve to 9.5 kg of alumina sol (alumina content is 20%), add an appropriate amount of water and slurry;

[0066] Add 1 kg of zinc oxide (ZnO), 2.02 kg of ferric nitrate, and 1.2 kg of silver oxide (Ag2O) and stir until homogeneous. Then add 0.04 kg of potassium carbonate (K2CO3) powder and continue stirring until the slurry is homogeneous. Finally, perform spray granulation to obtain solid microspheres.

[0067] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

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

[0069] Using naphtha as raw material, the performance of the multi-metal modified β-zeolite catalyst prepared in this example was evaluated on a riser pilot plant manufactured by Qingdao Jietian Technology Co., Ltd. The reaction temperature was 700℃ and the residence time was 3.5 s. The catalyst evaluation results showed that the single-pass total yield of ethylene and propylene reached 54.89%, and the methane yield was 8.97%.

[0070] Example 7

[0071] Add 6 kg of β molecular sieve to 10 kg of aluminum sol (alumina content is 20%), add an appropriate amount of water and slurry.

[0072] Add 4 kg of zinc nitrate (Zn(NO3)2·6H2O), 2 kg of magnesium nitrate (Mg(NO3)2·6H2O), 3 kg of ferric nitrate (Fe(NO3)3·9H2O), 0.2 kg of cerium oxide (CeO2), and 1.0 kg of silver nitrate (AgNO3) and stir until homogeneous. Then add 0.05 kg of potassium carbonate (K2CO3) powder and continue stirring until the slurry is homogeneous. Finally, perform spray granulation to obtain solid microspheres.

[0073] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

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

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

[0076] Example 8

[0077] Add 6.5 kg of β molecular sieve to 9.5 kg of alumina sol (alumina content is 20%), add an appropriate amount of water and slurry;

[0078] Add 0.05 kg gallium oxide (Ga2O3), 1.5 kg magnesium nitrate (Mg(NO3)2·6H2O), and 1.2 kg silver oxide (Ag2O) and stir until homogeneous. Continue stirring until the slurry is uniform, then perform spray granulation to obtain solid microspheres.

[0079] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

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

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

[0082] Example 9

[0083] Add 6.5 kg of β molecular sieve to 9.5 kg of alumina sol (alumina content is 20%), add an appropriate amount of water and slurry;

[0084] After adding 0.3 kg of cerium nitrate (Ce(NO3)3·6H2O) and 1.0 kg of silver nitrate (AgNO3) and stirring until homogeneous, 0.04 kg of potassium carbonate (K2CO3) powder was added. The mixture was stirred until homogeneous, and then spray granulation was performed to obtain solid microspheres.

[0085] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

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

[0087] 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 plant manufactured by Qingdao Jietian Technology Co., Ltd. The reaction temperature was 700℃ and the residence time was 3.5 s. The catalyst evaluation results showed that the single-pass total yield of ethylene and propylene reached 54%, and the methane yield was 9.06%.

[0088] Example 10

[0089] Add 6 kg of β molecular sieve to 10 kg of aluminum sol (alumina content is 20%), add an appropriate amount of water and slurry.

[0090] Add 0.5 kg of magnesium nitrate (Mg(NO3)3·6H2O), 1 kg of ferric nitrate (Fe(NO3)3·6H2O), 0.3 kg of cerium nitrate (Ce(NO3)3·6H2O), and 1.1 kg of silver oxide (Ag2O) and stir until homogeneous. Then add 0.04 kg of potassium carbonate (K2CO3) powder and continue stirring until the slurry is homogeneous. Finally, perform spray granulation to obtain solid microspheres.

[0091] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

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

[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 plant manufactured by Qingdao Jietian Technology Co., Ltd. The reaction temperature was 700℃ and the residence time was 3.5 s. The catalyst evaluation results showed that the single-pass total yield of ethylene and propylene reached 53.54%, and the methane yield was 9.13%.

[0094] Example 11

[0095] Add 7 kg of β molecular sieve to 11 kg of alumina sol (alumina content is 20%), add an appropriate amount of water and slurry.

[0096] Add 0.5 kg of magnesium oxide (MgO), 2 kg of iron oxide (Fe2O3), 0.05 kg of gallium oxide (Ga2O3) and 0.3 kg of cerium oxide (Ce2O3) and stir until the slurry is uniform. Then add 0.01 kg of potassium carbonate (K2CO3) powder and continue stirring until the slurry is uniform. Finally, perform spray granulation to obtain solid microspheres.

[0097] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

[0098] In the obtained catalyst, magnesium exists as magnesium oxide, iron as iron oxide, gallium as gallium oxide, cerium as cerium oxide, and potassium as potassium oxide. Alumina is used as a binder. The mass ratio of binder:molecular sieve:metal oxide in this catalyst 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-zeolite catalyst prepared in this example was evaluated on a riser pilot plant manufactured by Qingdao Jietian Technology Co., Ltd. The reaction temperature was 700℃ and the residence time was 3.5 s. The catalyst evaluation results showed that the single-pass total yield of ethylene and propylene reached 51.67%, and the methane yield was 9.28%.

[0100] Example 12

[0101] Add 6 kg of β molecular sieve to 10 kg of aluminum sol (alumina content is 20%), add an appropriate amount of water and slurry.

[0102] Add 2 kg of zinc nitrate (Zn(NO3)2·6H2O), 1.5 kg of iron oxide (Fe2O3), and 0.2 kg of cerium oxide (Ce2O3). Stir until the slurry is uniform, then add 0.08 kg of potassium carbonate (K2CO3) powder. Continue stirring until the slurry is uniform, and then perform spray granulation to obtain solid microspheres.

[0103] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

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

[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 plant manufactured by Qingdao Jietian Technology Co., Ltd. The reaction temperature was 700℃ and the residence time was 3.5 s. The catalyst evaluation results showed that the single-pass total yield of ethylene and propylene reached 53.78%, and the methane yield was 9.11%.

[0106] Example 13

[0107] Add 5 kg of β molecular sieve to 12 kg of aluminum sol (alumina content is 20%), add an appropriate amount of water and slurry.

[0108] Add 1 kg of zinc oxide (ZnO), 0.05 kg of gallium oxide (Ga2O3), and 1.2 kg of silver oxide (Ag2O). Stir until the slurry is uniform, then add 0.09 kg of potassium oxide (K2O) powder. Continue stirring until the slurry is uniform, and then perform spray granulation to obtain solid microspheres.

[0109] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

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

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

[0112] Example 14

[0113] Add 6 kg of β molecular sieve to 11 kg of alumina sol (alumina content is 20%), add an appropriate amount of water and slurry.

[0114] Add 1 kg of magnesium oxide (MgO), 0.2 kg of cerium oxide (Ce2O3), and 1.0 kg of silver nitrate (AgNO3). Stir until the slurry is uniform, then add 0.01 kg of potassium oxide (K2O) powder. Continue stirring until the slurry is uniform, and then perform spray granulation to obtain solid microspheres.

[0115] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

[0116] In the obtained catalyst, magnesium exists as magnesium oxide, cerium as cerium oxide, silver as silver oxide, and potassium as potassium oxide. Alumina is used as a binder. The mass ratio of binder:molecular sieve:metal oxide in this catalyst 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 plant manufactured by Qingdao Jietian Technology Co., Ltd. The reaction temperature was 700℃ and the residence time was 3.5 s. The catalyst evaluation results showed that the total single-pass yield of ethylene and propylene reached 52.99%, and the methane yield was 9.21%.

[0118] Example 15

[0119] Add 7 kg of β molecular sieve to 9 kg of alumina sol (alumina content is 20%), add an appropriate amount of water and slurry.

[0120] Add 0.1 kg magnesium oxide (MgO), 1 kg iron oxide (Fe2O3), 0.3 kg cerium oxide (Ce2O3), and 0.5 kg silver nitrate (AgNO3). Stir until the slurry is uniform, then add 0.4 kg potassium oxide (K2O) powder. Continue stirring until the slurry is uniform, and then perform spray granulation to obtain solid microspheres.

[0121] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

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

[0123] Using naphtha as raw material, the performance of the multi-metal modified β-zeolite catalyst prepared in this example was evaluated on a riser pilot plant manufactured by Qingdao Jietian Technology Co., Ltd. The reaction temperature was 700℃ and the residence time was 3.5 s. The catalyst evaluation results showed that the single-pass total yield of ethylene and propylene 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 alumina sol (alumina content is 20%), add an appropriate amount of water and slurry;

[0126] Add 0.6 kg gallium oxide (Ga2O3) and 5.72 kg magnesium nitrate (Mg(NO3)2·6H2O), stir until the slurry is uniform, then add 0.15 kg potassium carbonate (K2CO3) powder, continue stirring until the slurry is uniform, and then perform spray granulation to obtain solid microspheres.

[0127] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

[0128] In the obtained catalyst, gallium exists as gallium oxide, magnesium as magnesium oxide, and potassium as potassium oxide, with alumina as a binder. The mass ratio of binder:molecular sieve:metal oxide in this catalyst is 14:65:21; and 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-zeolite catalyst prepared in this example was evaluated on a riser pilot plant manufactured by Qingdao Jietian Technology Co., Ltd. The reaction temperature was 700℃ and the residence time was 3.5 s. The catalyst evaluation results showed that the total single-pass yield of ethylene and propylene reached 47.3%, and the methane yield was 12.31%.

[0130] Comparative Example 2

[0131] Add 3 kg of β molecular sieve to 18 kg of aluminum sol (alumina content is 20%), add an appropriate amount of water and slurry.

[0132] Add 5 kg of zinc nitrate (Zn(NO3)2·6H2O), 0.5 kg of iron oxide (Fe2O3), 0.5 kg of cerium oxide (CeO2), and 1.0 kg of silver nitrate (AgNO3). Stir until the slurry is uniform, then add 0.2 kg of potassium oxide (K2O) powder. Continue stirring until the slurry is uniform, and then perform spray granulation to obtain solid microspheres.

[0133] The solid microspheres were first calcined at 550℃ for 3 hours, and then calcined at 730℃ for 1.5 hours to obtain the catalytic cracking catalyst.

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

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

[0136] In Comparative Example 1, the alumina content was too low and the alkali metal content was too high, resulting in insufficient acidic sites in the catalyst, low olefin yield, and high methane yield. In Comparative Example 2, the molecular sieve content was too low and the metal oxide content was too high, resulting in low microporous acidity in the catalyst, excessive hydrocarbon activation, and low olefin yield. Appropriate alkali metals in the catalyst can neutralize excessive acidity, but excessive alkali metals will cause insufficient acidity in the catalyst and high methane yield. Other metal oxides besides alkali metals have appropriate activating effects on hydrocarbon molecules; therefore, the catalyst needs appropriate molecular sieve and alumina content, as well as a moderate amount of activating hydrocarbon metal oxides, to ensure sufficient catalytic performance.

[0137] Table 2 Evaluation Results

[0138]

[0139]

[0140] The technical solution of this application uses binders, transition metal modified β molecular sieves and alkali metal modification, and does not use phosphorus-containing compounds, thereby reducing the discharge of eutrophic wastewater.

Claims

1. A catalyst for catalytic cracking of metal-modified β-zeolites, characterized in that, In this catalyst, the mass ratio of binder, β-zeolite, and metal oxide is 16-24:52-68:12-28, wherein the metal oxide includes oxides of metal M1 and metal M2, and the oxide of metal M2 accounts for 1-25% of the total mass of the metal oxides. The oxide of metal M1 is an oxide of Zn, Fe, Ga, Ce or Ag, and the oxide of metal M2 is an oxide of Mg or K.

2. The catalytic cracking metal-modified β-zeolite catalyst according to claim 1, characterized in that, In this catalyst, the mass ratio of binder, β molecular sieve and metal oxide is 18-21:58-64:20-24.

3. The catalytic cracking metal-modified β-zeolite catalyst according to claim 1, characterized in that, The oxide of metal M2 accounts for 1-11% of the total mass of the metal oxide.

4. A method for preparing the metal-modified β-zeolite catalyst for catalytic cracking according to any one of claims 1-3, characterized in that, include: (1): Mix β molecular sieve with aluminum sol; (2): Add a soluble salt of the metal component; (3): Add potassium carbonate, stir until the slurry is uniform, and then perform spray granulation.

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

6. The method according to claim 4, characterized in that, In steps (1), (2) and (3), the stirring time is 0.5-3h.

7. The method according to claim 5, characterized in that, In step (4), the roasting is first carried out at 450-600℃ for 2-3 hours, and then roasted at 600-750℃ for 1-2 hours.

8. The application of the metal-modified β-zeolite catalyst of any one of claims 1-3 in the catalytic cracking of naphtha to ethylene and propylene.

9. A process for producing ethylene and propylene from naphtha through catalytic cracking, characterized in that, The metal-modified β-zeolite catalyst for catalytic cracking as described in any one of claims 1-3 is used.

10. The process according to claim 9, characterized in that, The catalytic cracking conditions are: reaction temperature 600-700℃, residence time 1-5s, and catalyst-to-oil ratio 3-10.

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