Method for synthesizing beta molecular sieve from spent catalyst residue of fcc

Abstract

The application belongs to the technical field of zeolite molecular sieve synthesis, and particularly provides a method for synthesizing Beta molecular sieve from FCC catalyst waste rubber residue. First, the FCC catalytic cracking waste rubber residue is subjected to high-temperature activation treatment, and the aluminum species therein is taken as a benchmark, and a silicon source is added to control Si / Al to form a silicon-aluminum gel, and hydrothermal crystallization is carried out at a suitable temperature and time. After crystallization, centrifugal filtration is carried out, and the Beta molecular sieve is obtained through drying and calcination after washing with deionized water until the pH is neutral. The method fully utilizes the silicon and aluminum elements in the rubber residue, can not only reduce the production cost of enterprises, but also realize efficient utilization of the FCC catalyst waste rubber residue.

Description

Technical Field

[0001] This invention belongs to the field of zeolite molecular sieve synthesis technology, and specifically provides a method for synthesizing Beta molecular sieves from FCC catalyst waste residue. Background Technology

[0002] Catalytic cracking catalysts (FCC catalysts) are widely used in secondary petroleum processing. However, the preparation of FCC catalysts often generates a large amount of wastewater. To reduce environmental pollution, this wastewater is typically treated through sedimentation and filtration, ultimately forming FCC catalyst waste residue. The main components of FCC catalyst waste residue are Al2O3, SiO2, and some rare earth oxides, such as lanthanum oxide and cerium oxide. Currently, the most common method for treating FCC catalyst waste residue is landfilling. This method has problems such as environmental pollution, waste of valuable metal resources, and increased production costs for enterprises, and it also occupies a large amount of land. In today's era of advocating clean production and achieving zero emissions, how to effectively recycle and utilize FCC catalyst waste residue has become an urgent problem to be solved.

[0003] Beta molecular sieve is a tetragonal crystal system and a high-silica zeolite with three-dimensional twelve-membered channels. It has one linear channel with a pore size of 0.76 × 0.67 nm and another curved channel system formed by the intersection of the linear channels with a pore size of approximately 0.55 × 0.55 nm. The pore size is between that of ZSM-5 molecular sieve and Y molecular sieve.

[0004] Besides the classic hydrothermal synthesis method, molecular sieve synthesis methods include solvothermal synthesis, seed-directed synthesis, dry gel conversion, ionothermal synthesis, and microwave-assisted synthesis. Meanwhile, methods for synthesizing zeolite molecular sieves using natural minerals have also been reported, such as the synthesis of Y-type molecular sieves from kaolin and ZSM-5 molecular sieves from fly ash. However, there are currently no reports on the synthesis of Beta molecular sieves using FCC catalyst waste residue as a raw material. Summary of the Invention

[0005] This invention provides a method for synthesizing Beta molecular sieves from FCC catalyst waste residue. This method is convenient and efficient, and the steps are as follows:

[0006] (1) Dry the untreated FCC catalyst waste residue in an oven at 100-130℃ to remove the moisture, and activate it in a muffle furnace at 550-700℃ for 2-3 hours to remove organic substances in the FCC catalyst waste residue that would affect the crystallization of zeolite molecular sieves.

[0007] (2) Stir sodium hydroxide, tetraethylammonium hydroxide (TEAOH) and deionized water at room temperature for 0.5-1h until they are mixed evenly; then add the FCC catalyst waste residue treated in step (1) as the total aluminum source and part of the silicon source of the molecular sieve, and stir at room temperature for 2-3h until they are mixed evenly.

[0008] (3) Based on Al2O3 in the waste gel residue of FCC catalyst, additional silica sol is added in step (2) to form Beta molecular sieve silica-alumina gel.

[0009] (4) The silica-alumina gel in step (3) is stirred and aged at room temperature for 0-24 hours, and then transferred to a crystallization kettle at 140-170℃ for hydrothermal crystallization under autogenous pressure for 3-4 days.

[0010] In this synthesis system, the initial molar ratio of the Beta molecular sieve mother liquor is:

[0011] SiO2:Al2O3:Na2O:TEAOH:H2O=20-50:1:2.0-2.6:8:400-700.

[0012] (5) After the reaction is completed, the Beta molecular sieve is obtained by cooling, centrifugation and filtration, drying at 100-130℃ and calcining at 550℃ for 4-6 hours.

[0013] The beneficial effects of the present invention include, but are not limited to:

[0014] (1) The method of the present invention only involves drying and calcining the waste glue residue of FCC catalyst and using a hydrothermal synthesis method, providing a new method for preparing Beta molecular sieves from industrial solid waste.

[0015] (2) The present invention uses the waste glue residue of FCC catalyst calcined at high temperature as part of the silicon source and all of the aluminum source. It can be synthesized using industrial-grade template agent. Its synthesis cost is low, the operation is simple, and it has strong economic benefits.

[0016] (3) The present invention examines and optimizes crystallization conditions such as crystallization temperature, time, silicon-aluminum ratio, basicity ratio, and water-silicon ratio to obtain suitable synthesis conditions. Attached Figure Description

[0017] Figure 1 The image shows the XRD patterns of the FCC catalyst waste gum-based Beta molecular sieves synthesized in Examples 1-8.

[0018] Figure 2 The image shows the TG-DSC diagram of the FCC catalyst waste gum-based Beta molecular sieve synthesized in Example 4. Detailed Implementation

[0019] The present invention will be further described with reference to the following embodiments, but it should be understood that these embodiments are for illustrative purposes only and should not be construed as limiting the implementation of the present invention.

[0020] The composition analysis of the FCC catalyst waste residue used in the specific embodiment of the present invention is as follows: The FCC catalyst waste residue was dried in an oven to remove a large amount of moisture; the main components in the residue were analyzed by XRF characterization. In terms of oxide mass fraction, the residue contained 51.1% SiO2, 18.9% Al2O3, 5.8% Na2O, 6.5% La2O3, 9.6% CeO2, 0.4% Fe2O3, 2.6% CaO, and 0.8% MgO. The remaining impurities accounted for less than 5.0% and could be ignored.

[0021] Example 1

[0022] (1) Place the FCC catalyst waste gum residue in a 120℃ oven and dry for 48 hours to remove excess moisture, and then activate it in a muffle furnace at 550℃ for 3 hours for later use.

[0023] (2) At room temperature, add 0.9g NaOH to 30.6mL of deionized water and stir until completely dissolved. Add 19.0g of 35wt% industrial grade tetraethylammonium hydroxide to the system and stir for 0.5h. Then add 3.0g of FCC catalyst waste gel residue and stir for 2h. Finally, add 30.0g of 40wt% alkaline silica sol (commercially available) dropwise under vigorous stirring to form the initial silica-alumina gel.

[0024] (3) After thorough stirring, the mixture was placed at room temperature and aged for 24 hours. Then, it was transferred to a crystallization vessel and crystallized at 150°C for 3 days. After the reaction was completed and cooled to room temperature, the filtrate was centrifuged and filtered to make it neutral (pH=7). It was dried at 100°C for 12 hours and calcined in a muffle furnace at a heating rate of 5°C / min to reach 550°C for 5 hours to obtain Beta molecular sieve.

[0025] Example 2

[0026] (1) Place the FCC catalyst waste gum residue in a 120℃ oven and dry for 48 hours to remove excess moisture, then heat it in a muffle furnace at 700℃ for 2 hours for later use.

[0027] (2) At room temperature, add 0.9g NaOH to 30.6mL of deionized water and stir until completely dissolved. Add 19.0g of 35wt% industrial grade tetraethylammonium hydroxide to the system and stir for 0.5h. Then add 3.0g of FCC catalyst waste gel residue and stir for 2h. Finally, add 30.0g of 40wt% alkaline silica sol dropwise under vigorous stirring to form the initial silica-alumina gel.

[0028] (3) After thorough stirring, the mixture was placed at room temperature and aged for 24 hours. Then, it was transferred to a crystallization vessel and crystallized at 150°C for 3 days. After the reaction was completed and cooled to room temperature, the filtrate was centrifuged and filtered with deionized water to make it neutral (pH=7). It was then dried in an oven at 100°C for 12 hours and then calcined in a muffle furnace at a heating rate of 5°C / min to reach 550°C for 5 hours to obtain Beta molecular sieve.

[0029] Example 3

[0030] (1) Same as step (1) in Example 1.

[0031] (2) Same as step (2) in Example 1.

[0032] (3) After thorough stirring, the mixture was placed at room temperature and aged for 24 hours. Then, it was transferred to a crystallization vessel and crystallized at 150°C for 4 days. After the reaction was completed and cooled to room temperature, the system was centrifuged and filtered with deionized water to make it neutral (pH=7). It was dried in an oven at 100°C for 12 hours, and then calcined in a muffle furnace at a heating rate of 5°C / min to reach 550°C for 5 hours to obtain Beta molecular sieve.

[0033] Example 4

[0034] (1) Same as step (1) in Example 1.

[0035] (2) Same as step (2) in Example 1.

[0036] (3) After thorough stirring, the mixture was placed at room temperature and aged for 24 hours. Then, it was transferred to a crystallization vessel and crystallized at 170°C for 3 days. After the reaction was completed and cooled to room temperature, the system was centrifuged and filtered with deionized water to make it neutral (pH=7). It was dried in an oven at 100°C for 12 hours, and then calcined in a muffle furnace at a heating rate of 5°C / min to reach 550°C for 5 hours to obtain Beta molecular sieve.

[0037] Example 5

[0038] (1) Same as step (1) in Example 1.

[0039] (2) At room temperature, 0.9 g NaOH was added to 30.6 mL of deionized water and stirred until completely dissolved. 19.0 g of 35 wt% industrial grade tetraethylammonium hydroxide was added to the system and stirred for 0.5 h. Then 3.0 g of FCC catalyst waste slag was added and stirred for 2 h. Finally, 38.5 g of 40 wt% alkaline silica sol was added dropwise under vigorous stirring to form the initial silica-alumina gel.

[0040] (3) Same as step (3) in Example 1.

[0041] Example 6

[0042] (1) Same as step (1) in Example 1.

[0043] (2) At room temperature, 0.9 g NaOH was added to 30.6 mL of deionized water and stirred until completely dissolved. 19.0 g of 35 wt% industrial grade tetraethylammonium hydroxide was added to the system and stirred for 0.5 h. Then 3.0 g of FCC catalyst waste slag was added and stirred for 2 h. Finally, 21.5 g of 40 wt% alkaline silica sol was added dropwise under vigorous stirring to form the initial silica-alumina gel.

[0044] (3) Same as step (3) in Example 1.

[0045] Example 7

[0046] (1) Same as step (1) in Example 1.

[0047] (2) At room temperature, add 0.8g NaOH to 30.6mL of deionized water and stir until completely dissolved. Add 19.0g of 35wt% industrial grade tetraethylammonium hydroxide to the system and stir for 0.5h. Then add 3.0g of FCC catalyst waste gel residue and stir for 2h. Finally, add 30.0g of 40wt% alkaline silica sol dropwise under vigorous stirring to form the initial silica-alumina gel.

[0048] (3) Same as step (3) in Example 1.

[0049] Example 8

[0050] (1) Same as step (1) in Example 1.

[0051] (2) At room temperature, add 0.9g NaOH to 20.4mL of deionized water and stir until completely dissolved. Add 19.0g of 35wt% industrial grade tetraethylammonium hydroxide to the system and stir for 0.5h. Then add 3.0g of FCC catalyst waste gel residue and stir for 2h. Finally, add 30.0g of 40wt% alkaline silica sol dropwise under vigorous stirring to form the initial silica-alumina gel.

[0052] (3) Same as step (3) in Example 1.

[0053] The XRD results show six distinct characteristic diffraction peaks at 2θ = 7.6°, 21.3°, 22.4°, 25.2°, 26.9°, and 29.3°, which are attributed to different crystal planes of the Beta molecular sieve. This indicates that the present invention successfully synthesized Beta molecular sieve using FCC catalyst waste residue. Furthermore, except for Examples 5 and 7, relatively pure phase Beta molecular sieves can be synthesized under other conditions. Among these, the highest relative crystallinity was observed under the synthesis conditions of Examples 1-4, reaching 93.5%, 92.0%, 85.3%, and 99.4%, respectively. Under the synthesis conditions of Examples 5-8, the crystallinity was 54.7%, 60.3%, 64.0%, and 79.4%, respectively.

[0054] Figure 2 The image shows the TG-DSC curve of the Beta molecular sieve synthesized in Example 4. The curve shows an exothermic peak at approximately 895°C, and the corresponding TG curve does not show a downward trend, indicating no mass loss. This demonstrates that the synthesized Beta molecular sieve only experiences framework collapse at around 895°C, exhibiting good thermal stability.

[0055] Based on the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of this invention. The technical scope of this invention is not limited to the contents of the specification; it must be determined according to the scope of the claims.

Claims

1. A method for synthesizing a Beta molecular sieve from FCC catalyst spent catalyst residue, characterized by, The method is carried out according to the following steps: (1) The FCC catalyst waste residue is placed in an oven for drying treatment, and then the silicon aluminum components therein are activated by high temperature calcination; (2) The sodium hydroxide, tetraethylammonium hydroxide TEAOH and deionized water are stirred at room temperature; then the treated FCC catalyst waste residue in step (1) is added as the total aluminum source and part of the silicon source of the molecular sieve, and stirred at room temperature; (3) The silicon sol is added in step (2) to form a Beta molecular sieve silicon aluminum gel, with Al2O3 in the FCC catalyst waste residue as the reference; The initial molar ratio of the Beta molecular sieve mother liquor is: SiO2:Al2O3:Na2O:TEAOH:H2O=20-50:1:2.0-2.6:8:400-700; (4) The silicon aluminum gel in step (3) is stirred at room temperature for 0-24 h, and then transferred to a crystallization kettle for hydrothermal crystallization at 140-170 ℃ for 3-4 d; after the reaction is completed, cooling, centrifugal filtration, drying and calcination are carried out to synthesize the Beta molecular sieve.

2. The method of synthesizing Beta zeolite from FCC catalyst spent catalysts according to claim 1, characterized in that, In step (1), the drying treatment temperature is 100-130 ℃.

3. The method of synthesizing Beta zeolite from FCC catalyst spent catalysts according to claim 1, characterized in that, In step (1), the high temperature calcination activation treatment temperature is 550-700 ℃, and the calcination activation treatment time is 2-3 h.

4. The method of synthesizing Beta zeolite from FCC catalyst spent catalysts according to claim 1, characterized in that, In step (2), the first mixing and stirring time is 0.5-1 h, and the second mixing and stirring time is 2-3 h.

5. The method of synthesizing Beta zeolite with FCC catalyst spent catalyst residue according to claim 1, characterized in that, In step (4), the drying temperature is 80-120 ℃, the drying time is 6-12 h, the calcination temperature is 550 ℃, and the calcination time is 4-6 h.

6. A Beta molecular sieve synthesized according to the method of any one of claims 1-5.

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