Extrusion process for titanium silicalite molecular sieve catalyst
By using a molding method that combines titanium-silicon molecular sieves and silica sol, the problems of reduced activity and insufficient strength of traditional titanium-silicon molecular sieve catalysts caused by impurities introduced by binders have been solved, resulting in a catalyst with high activity and high strength, suitable for fixed-bed processes.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2024-12-25
- Publication Date
- 2026-06-26
AI Technical Summary
The addition of binders during the traditional titanium-silicon molecular sieve extrusion process leads to a decrease in catalyst performance, and the strength of the catalyst after molding is insufficient to meet the requirements of fixed-bed processes.
The process involves uniformly mixing titanium-silicon molecular sieves, silica sol, plasticizers, extrusion aids, and pore-forming agents to form a slurry. The wet strip catalyst is then dried and calcined under specific temperature and humidity conditions to avoid the use of binders.
The catalyst has increased the content and activity of titanium-silicon molecular sieves, enhanced its resistance to compression and crushing, met the requirements of fixed-bed process, shortened extrusion time, and increased production capacity.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of petrochemical catalyst technology, specifically to a method for extruding titanium-silicon molecular sieve catalysts. Background Technology
[0002] Since its successful development in the 1980s, titanium-silicon molecular sieves have been applied to many green organic reactions, especially in reactions such as olefin epoxidation, phenol hydroxylation, and cyclohexanone oximeization, where they exhibit excellent catalytic performance and are environmentally friendly. Therefore, titanium-silicon molecular sieve catalysts have promising application prospects.
[0003] When fixed-bed processes are used in the application of titanium-silicon molecular sieves, the molecular sieves need to be extruded into strips. The extruded molecular sieves not only need high activity but also sufficient strength to meet the requirements of the fixed-bed process. In the traditional molecular sieve extrusion process, a certain amount of binder needs to be added to bond the molecular sieves together. However, adding the binder introduces impurities, especially aluminum, which significantly affects the activity of the titanium-silicon molecular sieves, thus reducing the performance of the catalyst after extrusion.
[0004] Therefore, in the process of extruding titanium-silicon molecular sieves, it is necessary to ensure the strength of the catalyst after molding and to increase the content of titanium-silicon molecular sieves in order to ensure the performance of the catalyst. Summary of the Invention
[0005] The purpose of this invention is to overcome the problem in the prior art that the addition of binders has a significant impact on the activity of titanium-silicon molecular sieves, thereby reducing the performance of the catalyst after molding. This invention provides a method for extruding titanium-silicon molecular sieve catalysts. The titanium-silicon molecular sieve catalysts prepared by this extrusion molding method have a higher titanium-silicon molecular sieve content and higher catalyst performance. At the same time, the compressive crushing strength of the titanium-silicon molecular sieve catalyst after extrusion molding meets the requirements of fixed bed process.
[0006] To achieve the above objectives, the present invention provides a method for extruding titanium-silicon molecular sieve catalysts, the method comprising the following steps: A. After uniformly mixing titanium silica molecular sieve, silica sol, plasticizer, extrusion aid, and pore-forming agent, knead the mixture to obtain mud. B. Extruding the mud material to obtain wet strip-shaped catalyst; C. Dry and calcine the wet strip catalyst; The drying conditions include: First, dry in air at 20℃-80℃ for 1-10 hours, then dry a second time in air at 100℃-150℃ for 1-10 hours.
[0007] Compared with the prior art, the present invention has at least the following beneficial effects: The extrusion molding method described in this invention shortens the extrusion time, increases the production capacity of catalyst extrusion, and has a higher titanium-silicon molecular sieve content, resulting in higher catalyst activity. The compressive strength of the extruded titanium-silicon molecular sieve catalyst meets the requirements for use in fixed-bed processes. Detailed Implementation
[0008] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0009] In this invention, relative humidity refers to the percentage of water vapor pressure in the air to the saturated water vapor pressure at the same temperature.
[0010] This invention provides a method for extruding titanium-silicon molecular sieve catalysts, the method comprising the following steps: A. After uniformly mixing titanium silica molecular sieve, silica sol, plasticizer, extrusion aid, and pore-forming agent, knead the mixture to obtain mud. B. Extruding the mud material to obtain wet strip-shaped catalyst; C. Dry and calcine the wet strip catalyst; The drying conditions include: First, dry in air at 20℃-80℃ for 1-10 hours, then dry a second time in air at 100℃-150℃ for 1-10 hours.
[0011] In the extrusion molding method of this invention, the catalyst is easy to knead and extrude during the extrusion process, which shortens the extrusion time and improves the production capacity of the extruded catalyst. At the same time, it has a high titanium-silicon molecular sieve content, resulting in higher catalyst activity. The compressive crushing strength of the titanium-silicon molecular sieve catalyst after extrusion molding meets the requirements of the fixed bed process.
[0012] In this invention, the objective of the invention can be achieved by first drying in air at 20℃-80℃ for 1-10 hours, followed by a second drying in air at 100℃-150℃ for 1-10 hours. For example, the first drying temperature can be 30℃, 40℃, 50℃, 60℃, 70℃, etc., all of which can achieve the objective of the invention. In this embodiment, 50℃ is used as an example to illustrate the advantages of the invention. Similarly, the second drying temperature can be 110℃, 120℃, 130℃, 140℃, etc. In this implementation, 120℃ is used as an example to illustrate the advantages of the invention. The aforementioned first and second drying times are selected and determined based on the drying temperature. For example, with a first drying temperature of 40-60℃, the selectable first drying time is approximately 4-6 hours; similarly, with a second drying temperature of 110-130℃, the selectable second drying time is approximately 4-6 hours.
[0013] According to one embodiment of the present invention, in the first drying process, the relative humidity of the air is 80%-100%, for example, 90%, and in the second drying process, the relative humidity of the air is 50%-70%, for example, 60%, 70%, etc. By employing the aforementioned preferred embodiment, the compressive strength of the extruded catalyst can be significantly improved.
[0014] In this invention, by changing the temperature and humidity at different drying stages, the carrier can be prevented from breaking during the drying process, which helps to increase the strength of the carrier.
[0015] In this invention, the amount of silica sol can be selected from a wide range, and the specific amount can be determined according to the actual situation. The following is an illustrative description, but it does not limit the scope of this invention. According to one embodiment of this invention, the mass of silica sol, based on SiO2, accounts for 30%-50% of the total mass of titanium silicon molecular sieve and SiO2, preferably 45%-50%.
[0016] In this invention, the amount of titanium-silicon molecular sieve can be selected from a wide range, and the specific amount can be determined according to the actual situation. The following is an illustrative description, but it does not limit the scope of this invention. According to one embodiment of this invention, the mass of titanium-silicon molecular sieve accounts for 50%-70% of the total mass of titanium-silicon molecular sieve and SiO2, preferably 50%-55%.
[0017] In this invention, the silica sol can be selected from a wide range, including both acidic and alkaline silica sols. In a preferred embodiment of this invention, the silica sol is an acidic silica sol.
[0018] In this invention, the range of types of titanium-silicon molecular sieves that can be selected is relatively wide. Various titanium-silicon molecular sieves can be formed using the method of this invention. The following is an illustrative description, but it does not limit the scope of this invention. According to one embodiment of this invention, the titanium-silicon molecular sieve is an MFI structure titanium-silicon molecular sieve, preferably TS-1 and / or TS-2.
[0019] In this invention, there is no special limitation on the specific composition of the titanium-silicon molecular sieve. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the titanium content of the framework of the titanium-silicon molecular sieve is 0.1-10 wt% based on oxides.
[0020] In this invention, the range of plasticizer dosage is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. According to one embodiment of this invention, the amount of plasticizer added is 0.5%-10% of the total mass of titanium silicon molecular sieve and SiO2, preferably 2.5%-4.5%.
[0021] In this invention, the range of plasticizers that can be selected is relatively wide, and can be one or more of phthalate compounds. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the plasticizer is one or more of dioctyl phthalate, di-n-octyl phthalate, di(2-ethylhexyl) phthalate, and di-n-butyl phthalate.
[0022] In this invention, the amount of extrusion aid can be selected from a wide range. The following is an illustrative description, but it does not limit the scope of this invention. According to one embodiment of this invention, the amount of extrusion aid added is 0.5%-10% of the total mass of titanium silicon molecular sieve and SiO2, preferably 3%-6%.
[0023] In this invention, the range of extrusion aids that can be selected is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. According to one embodiment of this invention, the extrusion aid is one or more of guar gum powder, starch, and citric acid.
[0024] In this invention, the amount of pore-forming agent can be selected from a wide range. The following is an illustrative description, but it does not limit the scope of this invention. According to one embodiment of this invention, the amount of pore-forming agent added is 0.5%-10% of the total mass of titanium silicon molecular sieve and SiO2, preferably 3%-6%.
[0025] In this invention, the range of pore-forming agents that can be selected is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. According to one embodiment of this invention, the pore-forming agent is one or more of polyethylene glycol, activated carbon, methylcellulose, and polyacrylamide.
[0026] In this invention, the method of uniformly mixing the titanium-silicon molecular sieve, silica sol, plasticizer, extrusion aid, and pore-forming agent in step A has no special requirements. The following is an illustrative description, but it does not limit the scope of the invention. According to one embodiment of the invention, step A includes: A1. Thoroughly mix the titanium-silicon molecular sieve and silica sol to obtain a first mixture. The preferred mixing conditions result in a solid content of 30-60 wt%, more preferably 40-50 wt%. A2. The first mixture is mixed evenly with plasticizer, extrusion aid, and pore-forming agent, and then kneaded to obtain the mud material; "Fully mixed" means that after thorough mixing, the water-soluble components are fully dissolved and the water-insoluble components are fully dispersed.
[0027] According to one embodiment of the present invention, step A2 does not require the addition of additional water, which is beneficial to increasing the molecular sieve content of the catalyst and improving the catalyst activity.
[0028] The key active ingredients in the plasticizers, extrusion aids, and pore-forming agents of the present invention are one or more mixtures described in the present invention. Those skilled in the art know that, for the sake of convenience in transportation, storage, or on-site use, various supply forms can be adopted, such as anhydrous solid form, aqueous solid form, aqueous paste form, or aqueous solution form; the aqueous solution form includes the form of a concentrated solution prepared with water, or the form of a solution prepared directly to the required concentration.
[0029] In this invention, there are no special requirements for roasting, and it can be carried out in accordance with conventional methods. The following is an illustrative description, but it does not limit the scope of this invention.
[0030] According to one embodiment of the present invention, the roasting conditions include a temperature of 400℃-800℃.
[0031] According to one embodiment of the present invention, the roasting conditions include a time of 1-10 hours.
[0032] The present invention will be described in detail below through embodiments.
[0033] In the following embodiments: Mechanical strength parameters were measured using a KQ-2 particle strength tester. The extrusion machine is an all-stainless steel product manufactured by Sinopec Catalyst Co., Ltd. The titanium-silicon molecular sieve was produced by Sinopec Catalyst Co., Ltd. All other raw materials were commercially available products.
[0034] The titanium-silicon molecular sieve used in the following examples is TS-1, with a framework titanium content of 4 wt%. The strength of the prepared catalyst is shown in Table 1.
[0035] Example 1 A1. Weigh 50g of titanium silica molecular sieve and 150g of acidic silica sol (solid content 30wt%) and mix them thoroughly to prepare the first mixture (solid content 47.5wt%). A2. Add 3g of dioctyl phthalate, 5g of guar gum powder, and 5g of polyethylene glycol to the first mixture and continue mixing evenly. Then knead the mixture to form a mud. B. The mud material is put into an extruder and extruded through a Φ1.5mm perforated plate to obtain wet strip-shaped catalyst; C. The wet strip catalyst was first dried in air at 50°C and 90% relative humidity for 4 hours, then dried again in air at 120°C and 70% relative humidity for 4 hours, and finally calcined at 550°C for 4 hours to obtain the titanium-silicon molecular sieve catalyst.
[0036] Example 2 The method is the same as in Example 1, except that the amount of acidic silica sol added is 120g (the solid content of the first mixture is 50.6wt%).
[0037] Example 3 The method is the same as in Example 1, except that the amount of acidic silica sol added is 100g (the solid content of the first mixture is 53.3wt%).
[0038] Example 4 The method is the same as in Example 1, except that the humidity of the air is 75% in the first drying process and 45% in the second drying process.
[0039] Example 5 The method is the same as in Example 1, except that the silica sol is an alkaline silica sol (solid content is 30wt%).
[0040] Example 6 The method is the same as in Example 1, except that 2g of dioctyl phthalate, 2g of guar gum powder, and 3g of polyethylene glycol are added.
[0041] Example 7 The method is the same as in Example 1, except that 5g of dioctyl phthalate, 8g of guar gum powder, and 1g of polyethylene glycol are added.
[0042] Example 8 The method is the same as in Example 1, except that in step A2: 3g of dioctyl phthalate, 5g of guar gum powder, and 5g of polyethylene glycol are added to the mixture and mixed evenly. Then, 10g of deionized water is added and kneaded to obtain a plastic body.
[0043] Example 9 The method is the same as in Example 1, except that... A. Weigh 50g of titanium silica molecular sieve, 150g of acidic silica sol (30wt%), 3g of dioctyl phthalate, 5g of guar gum powder, and 5g of polyethylene glycol, mix them evenly, and knead them into a mud. B. The mud material is put into an extruder and extruded through a Φ1.5mm perforated plate to obtain wet strip-shaped catalyst; C. The wet strip catalyst was first dried in air at 50°C and 90% relative humidity for 4 hours, then dried again in air at 120°C and 70% relative humidity for 4 hours, and finally calcined at 550°C for 4 hours to obtain the titanium-silicon molecular sieve catalyst.
[0044] Comparative Example 1 The method is the same as in Example 1, except that the first drying is performed in air at 85°C for 4 hours, and then in air at 160°C for 4 hours.
[0045] Comparative Example 2 The method is the same as in Example 1, except that no plasticizer or pore-forming agent is added.
[0046] Table 1. Catalyst strength
[0047] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.
Claims
1. A method for extruding titanium-silicon molecular sieve catalysts, characterized in that: The method includes the following steps: A. After uniformly mixing titanium silica molecular sieve, silica sol, plasticizer, extrusion aid, and pore-forming agent, knead the mixture to obtain mud. B. Extruding the mud material to obtain wet strip-shaped catalyst; C. Dry and calcine the wet strip catalyst; The drying conditions include: First, dry in air at 20℃-80℃ for 1-10 hours, then dry a second time in air at 100℃-150℃ for 1-10 hours.
2. The method according to claim 1, wherein, During the first drying process, the relative humidity of the air is 80%-100%, and during the second drying process, the relative humidity of the air is 50%-70%.
3. The method according to claim 1 or 2, wherein, In step A, The silica sol, based on SiO2, accounts for 30%-50% of the total mass of the titanium-silicon molecular sieve and SiO2, preferably 45%-50%. and / or The mass of the titanium-silicon molecular sieve accounts for 50%-70% of the total mass of the titanium-silicon molecular sieve and SiO2, preferably 50%-55%.
4. The method according to any one of claims 1-3, wherein, In step A, The silica sol is an acidic silica sol and / or an alkaline silica sol, preferably an acidic silica sol; and / or The titanium-silicon molecular sieve is an MFI structure titanium-silicon molecular sieve, preferably TS-1 and / or TS-2; and / or The titanium content in the framework of the titanium-silicon molecular sieve is 0.1-10 wt% based on oxides.
5. The method according to any one of claims 1-4, wherein, In step A, The amount of plasticizer added is 0.5%-10% of the total mass of titanium-silicon molecular sieve and SiO2, preferably 2.5%-4.5%.
6. The method according to any one of claims 1-5, wherein, In step A, The plasticizer is one or a mixture of two or more phthalate compounds; Preferably, the plasticizer is one or more of dioctyl phthalate, di-n-octyl phthalate, di(2-ethylhexyl) phthalate, and di-n-butyl phthalate.
7. The method according to any one of claims 1-6, wherein, In step A, The amount of the extrusion aid added is 0.5%-10% of the total mass of the titanium-silicon molecular sieve and SiO2, preferably 3%-6%; and / or The extrusion aid is one or more of guar gum powder, starch, and citric acid.
8. The method according to any one of claims 1-7, wherein, In step A, The amount of the pore-forming agent added is 0.5%-10% of the total mass of the titanium-silicon molecular sieve and SiO2, preferably 3%-6%; and / or The pore-forming agent is one or more of polyethylene glycol, activated carbon, methylcellulose, and polyacrylamide.
9. The method according to any one of claims 1-8, wherein, Step A includes: A1. Thoroughly mix the titanium-silicon molecular sieve and silica sol to obtain a first mixture. The preferred mixing conditions result in a solid content of 30-60 wt%, more preferably 40-50 wt%. A2. The first mixture is mixed evenly with plasticizer, extrusion aid, and pore-forming agent, and then kneaded to obtain the mud material; Preferably, no additional water is added in step A2.
10. The method according to any one of claims 1-9, wherein, Calcination conditions include: The temperature range is 400℃-800℃; and / or The time is 1-10 hours.