Ethylbenzene dehydrogenation catalyst and method for recycling ethylbenzene dehydrogenation catalyst powder at high temperature
By optimizing the recycling method of high-temperature powder, the problems of poor catalyst strength and low yield were solved, achieving efficient recycling and utilization of catalysts and environmental protection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2024-11-29
- Publication Date
- 2026-05-29
AI Technical Summary
In existing technologies, the high-temperature powder of ethylbenzene dehydrogenation catalysts is difficult to reuse, resulting in poor catalyst strength, low yield, and the disposal of waste can easily cause environmental pollution.
By dry mixing, wet kneading, adding binders to form and drying high-temperature powder, controlling moisture and calcination conditions, catalyst semi-finished products and finished products are prepared, and particle size and moisture content are optimized.
This improved the mechanical properties and yield of the catalyst, reduced environmental pollution, and lowered production costs.
Smart Images
Figure CN122098728A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of catalysts, specifically to an ethylbenzene dehydrogenation catalyst and a method for recycling high-temperature powder of the ethylbenzene dehydrogenation catalyst. Background Technology
[0002] Ethylbenzene dehydrogenation catalysts are mostly in strip form. Their production process mainly includes kneading, extrusion, drying, pelletizing, sieving, and calcination. Sieving involves using a vibrating screen to remove materials that do not meet length requirements after drying or calcination, and then separating them through a sieve with a specific mesh size. The catalyst semi-finished material obtained from drying, pelletizing, and sieving can be recycled through blending or complete reuse. However, if the catalyst powder obtained after high-temperature calcination and sieving is not utilized, it not only wastes materials and increases catalyst production costs, but also easily leads to environmental pollution. Therefore, researching high-temperature powder recycling technology has become an important issue that needs to be studied in the production of ethylbenzene dehydrogenation catalysts. Summary of the Invention
[0003] The purpose of this invention is to overcome the technical problems of existing technologies, such as the difficulty in handling high-temperature powder of ethylbenzene dehydrogenation catalyst above 800°C and the poor strength of catalyst obtained by recycling, and to provide an ethylbenzene dehydrogenation catalyst and a method for recycling high-temperature powder of ethylbenzene dehydrogenation catalyst.
[0004] To achieve the above objectives, the first aspect of the present invention provides a method for recycling high-temperature powder of ethylbenzene dehydrogenation catalyst, wherein the method includes the following steps:
[0005] (1) The high-temperature powder is dry-mixed and stirred;
[0006] (2) Mix the material obtained in step (1) with water and knead it wet, then add a binder for molding and drying to obtain a catalyst semi-finished product;
[0007] (3) The catalyst semi-finished product is calcined to obtain the catalyst finished product;
[0008] The high-temperature powder is fine powder with an average particle size of 2.5-3.5 mm.
[0009] The moisture content of the high-temperature powder is 0.5wt%-3wt%.
[0010] The high-temperature powder is obtained by calcining ethylbenzene dehydrogenation catalyst waste at 800-1000℃ for 10-15 hours.
[0011] The second aspect of the present invention provides an ethylbenzene dehydrogenation catalyst prepared by the method described in the first aspect;
[0012] Preferably, the catalyst has an abrasion intensity of 150-170 N / 5 mm, an average particle size of 2.5-3.5 mm, and a bulk density of 145-160 g / 100 mL.
[0013] Through the above technical solution, the present invention achieves the following beneficial technical effects:
[0014] This invention reuses the high-temperature powder generated during the production of ethylbenzene dehydrogenation catalyst. It employs a batch-by-batch, multiple-stage wet kneading process, controlling the amount of water and kneading time to fully soften and mix the raw materials into a ball. Simultaneously, it controls the process conditions for molding, drying, and calcination. This solves the problems of difficult-to-control raw material moisture content, poor catalyst strength obtained from reuse, and low yield of ethylbenzene dehydrogenation catalyst, significantly improving the yield of ethylbenzene dehydrogenation catalyst and greatly enhancing the mechanical properties of the reused ethylbenzene dehydrogenation catalyst. Attached Figure Description
[0015] Figure 1 This is an image of catalyst A1 prepared using the method described in Example 1.
[0016] Figure 2 This is an image of catalyst B1 prepared using the method of Comparative Example 1. Detailed Implementation
[0017] 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.
[0018] To achieve the above objectives, the first aspect of the present invention provides a method for recycling high-temperature powder of ethylbenzene dehydrogenation catalyst, wherein the method includes the following steps:
[0019] (1) The high-temperature powder is dry-mixed and stirred;
[0020] (2) The material obtained in step (1) is wet-kneaded with water, and then a binder is added for molding and drying to obtain a catalyst semi-finished product;
[0021] (3) The catalyst semi-finished product is calcined to obtain the catalyst finished product;
[0022] The high-temperature powder is fine powder with an average particle size of 2.5-3.5 mm.
[0023] The moisture content of the high-temperature powder is 0.5wt%-3wt%.
[0024] The high-temperature powder is obtained by calcining ethylbenzene dehydrogenation catalyst waste at 800-1000℃ for 10-12 hours.
[0025] In this invention, a large average particle size of the high-temperature powder will result in incomplete catalyst conversion and failure to achieve the expected effect, while a small average particle size of the high-temperature powder will cause carbon buildup during the reaction process; when the average particle size of the high-temperature powder meets the above-mentioned limiting range, the possibility of the above situation can be reduced to a certain extent.
[0026] In this invention, if the moisture content of the high-temperature powder is too high, the catalyst will be difficult to form, while if the moisture content of the high-temperature powder is too low, the wet-kneaded catalyst will dry and crack, making it impossible to extrude and form. When the moisture content of the high-temperature powder meets the above-mentioned limit range, a catalyst semi-finished product that meets the requirements can be successfully formed.
[0027] In this invention, the high-temperature powder of the ethylbenzene dehydrogenation catalyst refers to the catalyst waste generated during the production and preparation of the ethylbenzene dehydrogenation catalyst, which is obtained by high-temperature calcination. Since the ethylbenzene dehydrogenation catalyst waste can currently only be disposed of as hazardous waste, in order to reduce costs and increase efficiency while minimizing environmental impact, the aforementioned powder needs to be recycled.
[0028] According to some aspects of the present invention, the total amount of water used is 10-25 kg, preferably 15-20 kg, based on the weight of 100 kg of the high-temperature powder.
[0029] In this invention, when the amount of water used meets the above-mentioned limits, the material can be fully softened and mixed into a ball, making it easy to control the moisture content in the material.
[0030] According to some embodiments of the present invention, the mixing method includes kneading the moisture with the material obtained in step (1) 3-5 times.
[0031] In this invention, the purpose of adding water in batches is to ensure that the material is fully mixed with other samples. When the above method is used for mixing, a uniform mixing effect is achieved.
[0032] According to some embodiments of the present invention, the dry mixing time is 50-80 min, preferably 60-75 min.
[0033] In this invention, there is no particular limitation on the dry mixing method, as long as the materials are fully mixed, such as in a dry mixer.
[0034] According to some embodiments of the present invention, the adhesive is selected from at least one of sodium carboxymethyl cellulose, sodium polyacrylate, and polyvinyl alcohol.
[0035] In a preferred embodiment, the amount of binder is 4wt%-8wt% based on the weight of the high-temperature powder.
[0036] In this invention, when the type and amount of the binder meet the above-mentioned range, all materials are fully mixed and can be successfully extruded into strips.
[0037] According to some embodiments of the present invention, the conditions for wet kneading include: the kneading discharge temperature is 50-70°C.
[0038] In this invention, there is no particular limitation on the wet kneading method, as long as the materials are fully mixed and the moisture content of the materials is within a certain range, such as in a 2t / h kneading machine.
[0039] According to some embodiments of the present invention, the molding conditions include: the extrusion current is 40-60A.
[0040] In this invention, there is no particular limitation on the molding method, as long as the catalyst can be obtained in the desired shape, such as extruding and pelletizing wet kneaded material.
[0041] According to some embodiments of the present invention, the length of the catalyst semi-finished product is 1-20 mm, preferably 3-10 mm.
[0042] In this invention, the length of the catalyst semi-finished product meets the above-mentioned preferred range, which can obtain a reusable catalyst with satisfactory bulk density and wear strength, while improving the catalyst yield.
[0043] According to some embodiments of the present invention, the drying method includes first performing conditioning drying, and then performing drying treatment to obtain a catalyst semi-finished product.
[0044] In a preferred embodiment, the conditions for the health-preserving drying include: a health-preserving drying temperature of 30℃-40℃ and a drying time of 5h-6h.
[0045] In a preferred embodiment, the drying process includes a first stage of drying, a second stage of drying, and a third stage of drying.
[0046] More preferably, the total drying time is 8-11 hours, and the temperatures of the first, second, and third drying stages are each independently set at 40°C-80°C. To prevent rapid evaporation of moisture from the catalyst during drying, which could lead to catalyst cracking, more preferably, the temperatures of the first, second, and third drying stages are incremental, for example, the temperature of the first drying stage is 30-45°C, the temperature of the second drying stage is 45-60°C, and the temperature of the third drying stage is 60-80°C.
[0047] In a more preferred scenario, the drying time for the first stage is 2-3 hours, the drying time for the second stage is 3-4 hours, and the drying time for the third stage is 3-4 hours.
[0048] In this invention, the purpose of both the conditioning drying and the re-drying is to slowly evaporate the moisture in the catalyst and prevent the catalyst from cracking.
[0049] According to some embodiments of the present invention, the calcination temperature is 800-1000℃ and the time is 10-15h; preferably 750-850℃ and 10-12h.
[0050] In this invention, there is no particular limitation on the roasting method; for example, it can be carried out in a muffle furnace.
[0051] The second aspect of the present invention provides an ethylbenzene dehydrogenation catalyst prepared by the method described in the first aspect.
[0052] Preferably, the catalyst has an abrasion intensity of 150-170 N / 5 mm, an average particle size of 2.5-3.5 mm, and a bulk density of 145-160 g / 100 mL.
[0053] In this invention, the wear intensity of the catalyst is measured using a wear tester, model DGM.
[0054] In this invention, the particle size of the catalyst is determined using a sieve and a particle size analyzer.
[0055] In this invention, the bulk density of the catalyst is determined using a tap density meter.
[0056] The present invention will be described in detail below through embodiments.
[0057] In the examples and comparative examples, all raw materials were commercially available.
[0058] Example 1
[0059] The method for reusing high-temperature powder of ethylbenzene dehydrogenation catalyst includes the following steps:
[0060] (1) Weigh 320kg of high-temperature powder and add it to the dry mixer, and dry mix for 60min;
[0061] Among them, the high-temperature powder is obtained by calcining the waste of ethylbenzene dehydrogenation catalyst at 900℃ for 10 hours; the high-temperature powder is fine powder with a particle size of 3.08 mm and a moisture content of 1.78 wt%.
[0062] (2) After dry mixing, add 17 kg of water in three equal portions for wet kneading; after wet kneading, add 12 kg of binder (sodium carboxymethyl cellulose) for extrusion and pelletizing. The extruded catalyst is cured and dried in a pre-dryer and then dried again in a belt dryer to obtain a catalyst semi-finished product.
[0063] The kneading discharge temperature is 65℃, and the extrusion current is 50A; the length of the catalyst semi-finished product is 3.4mm; the conditioning and drying conditions include: conditioning and drying temperature of 40℃ for 6 hours; the total time for secondary drying is 8 hours, and the secondary drying conditions include: the temperature of the first stage drying is 45℃ for 2 hours; the temperature of the second stage drying is 60℃ for 3 hours; and the temperature of the third stage drying is 75℃ for 3 hours.
[0064] (3) The catalyst semi-finished product is roasted to obtain the catalyst finished product A1;
[0065] The roasting temperature was 850℃ and the time was 8 hours.
[0066] Example 2
[0067] The method for reusing high-temperature powder of ethylbenzene dehydrogenation catalyst includes the following steps:
[0068] (1) Weigh 320 kg of high-temperature powder and add it to a dry mixer, and dry mix for 65 min;
[0069] Among them, the high-temperature powder is obtained by calcining the waste of ethylbenzene dehydrogenation catalyst at 900℃ for 10 hours; the high-temperature powder is fine powder with a particle size of 3.08 mm and a moisture content of 1.78 wt%.
[0070] (2) After dry mixing, add 17 kg of water in three equal portions for wet kneading; after wet kneading, add 12 kg of binder (sodium carboxymethyl cellulose) for extrusion and pelletizing. The extruded catalyst is cured and dried in a pre-dryer and then dried again in a belt dryer to obtain a catalyst semi-finished product.
[0071] The kneading discharge temperature is 65℃; the forming conditions include: extrusion current of 50A; the length of the catalyst semi-finished product is 3.4mm; the curing and drying conditions include: curing and drying temperature of 40℃ for 6 hours; the total time for secondary drying is 8 hours, and the secondary drying conditions include: the temperature of the first stage of drying is 45℃ for 2 hours; the temperature of the second stage of drying is 60℃ for 3 hours; and the temperature of the third stage of drying is 75℃ for 3 hours.
[0072] (3) The catalyst semi-finished product is roasted to obtain the catalyst finished product A2;
[0073] The roasting temperature was 850℃ and the time was 8 hours.
[0074] Example 3
[0075] The method for reusing high-temperature powder of ethylbenzene dehydrogenation catalyst includes the following steps:
[0076] (1) Weigh 320kg of high-temperature powder and add it to the dry mixer, and dry mix for 60min;
[0077] Among them, the high-temperature powder is obtained by calcining the waste of ethylbenzene dehydrogenation catalyst at 900℃ for 10 hours; the high-temperature powder is fine powder with a particle size of 3.08 mm and a moisture content of 1.78 wt%.
[0078] (2) After dry mixing, add 23 kg of water in three equal portions for wet kneading; after wet kneading, add 12 kg of binder (sodium carboxymethyl cellulose) for extrusion and pelletizing. The extruded catalyst is cured and dried in a pre-dryer and then dried again in a belt dryer to obtain a catalyst semi-finished product.
[0079] The kneading discharge temperature is 65℃; the forming conditions include: extrusion current of 50A; the length of the catalyst semi-finished product is 3.4mm; the curing and drying conditions include: curing and drying temperature of 40℃ for 6 hours; the total time for secondary drying is 8 hours, and the secondary drying conditions include: the temperature of the first stage of drying is 45℃ for 2 hours; the temperature of the second stage of drying is 60℃ for 3 hours; and the temperature of the third stage of drying is 75℃ for 3 hours.
[0080] (3) The catalyst semi-finished product is calcined to obtain the catalyst finished product A3;
[0081] The roasting temperature was 850℃ and the time was 8 hours.
[0082] Example 4
[0083] The method of Example 1 is followed, except that the kneading discharge temperature is 90°C, and the catalyst product A4 is obtained.
[0084] Example 5
[0085] The method of Example 1 is followed, except that the length of the catalyst semi-finished product is 15 mm, and the catalyst finished product A5 is obtained.
[0086] Example 6
[0087] The method of Example 1 is different in that, in step (2), the catalyst formed by extrusion is only cured and dried to obtain catalyst product A6.
[0088] Example 7
[0089] The method of Example 1 is followed, except that the binder is silica sol, and catalyst product A7 is obtained.
[0090] Comparative Example 1
[0091] The method of Example 1 is different in that the high-temperature powder is obtained by roasting the waste of ethylbenzene dehydrogenation catalyst at 800°C for 8 hours, and the catalyst product B1 is obtained.
[0092] Comparative Example 2
[0093] The method is the same as in Example 1, except that the high-temperature powder is not subjected to high-temperature calcination to obtain catalyst product B2.
[0094] Comparative Example 3
[0095] The method of Example 1 was followed, except that the moisture content of the high-temperature powder was 5.3 wt%, resulting in catalyst product B3.
[0096] Comparative Example 4
[0097] The method of Example 1 is followed, except that the particle size of the high-temperature powder is 5 mm, and the catalyst product B4 is obtained.
[0098] Comparative Example 5
[0099] Using conventional iron oxide red and iron yellow as raw materials, strip-shaped catalyst carriers with a length of 10 mm were prepared by kneading, extruding, drying, granulating and calcining.
[0100] The strip catalyst was dry-mixed for 1 hour and wet-kneaded for 45 minutes under normal temperature and pressure conditions. It was then dried again in a pre-dryer and a belt dryer to obtain a catalyst semi-finished product. The semi-finished product was calcined in a muffle furnace to obtain the catalyst finished product B5.
[0101] Test case
[0102] The catalysts A1-A7 and B1-B5 in Examples 1-7 and Comparative Examples 1-5 were subjected to performance tests for wear strength, average particle size and bulk density, respectively. The specific results are shown in Table 1.
[0103] The abrasion intensity of the catalyst was measured using an abrasion tester, model DGM.
[0104] The particle size of the catalyst was determined using a sieve and a particle size analyzer.
[0105] The bulk density of the catalyst was determined using a tap density meter.
[0106] Table 1
[0107]
[0108] By employing the method of the present invention, through multiple wet kneading in batches, the amount of water and kneading time are controlled to fully soften and mix the raw materials into a ball. At the same time, the process conditions of molding, drying and calcination are controlled, thereby solving the problems of difficulty in controlling the moisture content of raw materials and poor strength of the recycled catalyst. This greatly improves the mechanical properties of the recycled catalyst. As can be seen from Examples 1-3, by adopting the preferred embodiment of the present invention, a recycled catalyst with excellent mechanical properties and high recovery rate can be prepared.
[0109] A comparison of Example 1 with Examples 4-7 shows that the preferred method for recycling high-temperature powder of ethylbenzene dehydrogenation catalyst can further improve the mechanical properties and yield of the recycled catalyst.
[0110] Compared to Example 1, in Comparative Example 1, the calcination time of the ethylbenzene dehydrogenation catalyst waste was shortened, resulting in increased particle size and bulk density of the recycled catalyst, and decreased wear strength and catalyst yield. In Comparative Example 2, the ethylbenzene dehydrogenation catalyst waste was not subjected to high-temperature calcination but was directly subjected to wet kneading, molding, and drying, resulting in increased particle size of the recycled catalyst, and decreased bulk density and catalyst yield. In Comparative Example 3, the high-temperature powder had a high moisture content, resulting in increased particle size and wear strength of the recycled catalyst, and decreased catalyst yield. In Comparative Example 4, the high-temperature powder had a large particle size, resulting in a significant increase in wear strength of the recycled catalyst, and decreased catalyst yield. In Comparative Example 5, the catalyst prepared by conventional methods had a large particle size, low bulk density, high wear strength, and decreased catalyst yield.
[0111] In summary, the method of the embodiments of the present invention can prepare reusable catalysts with excellent mechanical properties and high yield.
[0112] 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 recycling high-temperature powder of ethylbenzene dehydrogenation catalyst, characterized in that, The method includes the following steps: (1) The high-temperature powder is dry-mixed and stirred; (2) Mix the material obtained in step (1) with water and knead it wet, then add a binder for molding and drying to obtain a catalyst semi-finished product; (3) The catalyst semi-finished product is calcined to obtain the catalyst finished product; The high-temperature powder is fine powder with an average particle size of 2.5-3.5 mm. The moisture content of the high-temperature powder is 0.5wt%-3wt%. The high-temperature powder is obtained by calcining ethylbenzene dehydrogenation catalyst waste at 800-1000℃ for 10-12 hours.
2. The method according to claim 1, wherein, Based on the weight of 100 kg of the high-temperature powder, the total amount of water used is 10-25 kg, preferably 15-20 kg.
3. The method according to claim 1 or 2, wherein, The kneading method includes kneading the moisture with the material obtained in step (1) 3-5 times.
4. The method according to any one of claims 1-3, wherein, The dry mixing time is 50-80 minutes, preferably 60-75 minutes.
5. The method according to any one of claims 1-4, wherein, The adhesive is selected from at least one of sodium carboxymethyl cellulose, sodium polyacrylate and polyvinyl alcohol; Preferably, the amount of binder is 4wt%-8wt% based on the weight of the high-temperature powder.
6. The method according to any one of claims 1-5, wherein, The conditions for wet kneading include: the kneading discharge temperature is 50-70℃; And / or, the forming conditions include: the extrusion current is 40-60A.
7. The method according to any one of claims 1-6, wherein, The length of the catalyst semi-finished product is 1-20 mm, preferably 3-10 mm.
8. The method according to any one of claims 1-7, wherein, The drying method includes first performing conditioning drying, and then performing drying treatment to obtain the catalyst semi-finished product; Preferably, the conditions for the health-preserving drying include: a temperature of 30℃-40℃ and a time of 5h-6h; Preferably, the drying process includes a first stage of drying, a second stage of drying, and a third stage of drying; More preferably, the total drying time is 8-11 hours, the first drying stage is 2-3 hours, the second drying stage is 3-4 hours, and the third drying stage is 3-4 hours. More preferably, the temperature of the first drying stage is 30-45℃, the temperature of the second drying stage is 45-60℃, and the temperature of the third drying stage is 60-80℃.
9. The method according to any one of claims 1-8, wherein, The roasting temperature is 800-1000℃, preferably 750-850℃; the roasting time is 10-15h, preferably 10-12h.
10. An ethylbenzene dehydrogenation catalyst prepared by the method of any one of claims 1-9; preferably, the ethylbenzene dehydrogenation catalyst has an abrasion strength of 150-170 N / 5 mm, an average particle size of 2.5-3.5 mm, and a bulk density of 145-160 g / 100 mL.