Ethylbenzene dehydrogenation catalyst, preparation method and application thereof

Abstract

The application relates to the technical field of catalysts, and provides an ethylbenzene dehydrogenation catalyst as well as a preparation method and application thereof. The catalyst is prepared from raw materials including catalyst waste, red mud, an activator, a binder and a pore-forming agent; the catalyst waste is waste generated in the production process of an Fe-K-Ce-Mo catalyst. The catalyst provided by the application reuses the two industrial wastes of red mud and catalyst waste, achieves economic effects, and achieves good environmental protection effects; the catalytic performance of the catalyst is basically equivalent to that of a conventional Fe-K-Ce-Mo catalyst, and the strength is better.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and more specifically, to an ethylbenzene dehydrogenation catalyst, its preparation method, and its application. Background Technology

[0002] Styrene production methods include ethylbenzene dehydrogenation, propylene oxide / styrene monomer co-production (PO / SM process), styrene extraction from cracked gasoline, butadiene synthesis, and toluene-methanol side-chain alkylation to styrene. Among these, ethylbenzene dehydrogenation is currently the mainstream technology for styrene production worldwide, with mature industrial applications, and its capacity accounts for approximately 85% of the total styrene production capacity.

[0003] Catalysts for the dehydrogenation of ethylbenzene to styrene typically consist of a main catalyst, a co-catalyst, a pore-forming agent, and a reinforcing agent. In the past few decades, Fe-K-Cr catalysts were the mainstream catalysts for the dehydrogenation of ethylbenzene to styrene, widely used due to their excellent catalytic performance. However, in the 1980s, researchers developed Fe-K-Ce-Mo catalysts, which improved the catalytic activity, selectivity, and stability of the catalyst by replacing the Cr component with Ce and Mo components, while avoiding the environmental pollution caused by Cr oxides.

[0004] The production process of Fe-K-Ce-Mo catalysts generates a certain amount of catalyst waste, including powders, fragments, and other unformed materials or materials with insufficient catalyst strength. Currently, there is no reasonable application method for this type of catalyst waste, and the most common approach is to treat it directly as industrial waste. Therefore, it is of great significance to find a way to rationally utilize this catalyst waste resource to generate greater economic benefits. Summary of the Invention

[0005] The purpose of this invention is to provide an ethylbenzene dehydrogenation catalyst, its preparation method, and its application, so as to solve the technical problem that the waste generated in the production process of Fe-K-Ce-Mo catalysts in the prior art is difficult to use rationally.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides an ethylbenzene dehydrogenation catalyst, which is prepared from raw materials including catalyst waste, red mud, activator, binder and pore-forming agent; the catalyst waste is waste generated during the production process of Fe-K-Ce-Mo catalyst.

[0008] It should be noted that the "waste generated during the production of Fe-K-Ce-Mo catalysts" in this invention refers to powder, fragments, and catalyst waste with unacceptable strength generated during the production of Fe-K-Ce-Mo catalysts.

[0009] According to some embodiments of the present invention, the red mud is a deposited type of red mud.

[0010] Red mud is an industrial solid waste discharged after alumina extraction from bauxite. Its main components include SiO2, Al2O3, CaO, and Fe2O3. Depending on the source of bauxite, production process, and technological level, the resulting red mud can be classified into Bayer process red mud, sintering process red mud, and combined process red mud. Bayer process red mud is treated in three ways: marine disposal, lagoon disposal, and dry disposal. Accumulated red mud is dry-disposed Bayer process red mud.

[0011] In this invention, stacked red mud is used as the raw material for preparing the catalyst, which is more conducive to improving the crushing strength and activity of the catalyst compared with other types of red mud.

[0012] According to some embodiments of the present invention, the red mud has a water content of 10-15 wt% and a sodium oxide content of no more than 8 wt%.

[0013] According to some embodiments of the present invention, the activator includes at least one of lime, desulfurized gypsum, and water glass.

[0014] According to some embodiments of the present invention, the activator includes lime and water glass.

[0015] In this invention, the use of lime and water glass as activators, compared with the use of lime or water glass alone, allows for a more stable catalyst structure and higher crushing strength.

[0016] According to some embodiments of the present invention, the mass ratio of lime to water glass in the activator is 1:0.7 to 1.3; for example, 1:1.

[0017] According to some embodiments of the present invention, the binder includes at least one of guar gum powder, polyethylene, polyvinyl chloride, and carboxymethyl cellulose.

[0018] According to some embodiments of the present invention, the binder comprises guar gum powder and carboxymethyl cellulose.

[0019] In this invention, using guar gum powder and carboxymethyl cellulose as binders makes it easier for the materials to bond together during the catalyst kneading and extrusion process compared to using guar gum powder or carboxymethyl cellulose alone.

[0020] According to some embodiments of the present invention, the mass ratio of guar gum powder to carboxymethyl cellulose in the binder is 0.5 to 0.8:1.

[0021] According to some embodiments of the present invention, the pore-forming agent includes at least one of polyvinyl alcohol cellulose, polyethylene glycol, and hydroxypropyl cellulose.

[0022] According to some embodiments of the present invention, the pore-forming agent includes polyvinyl alcohol cellulose and hydroxypropyl cellulose.

[0023] In this invention, the use of polyvinyl alcohol cellulose and hydroxypropyl cellulose as pore-forming agents results in a more uniform distribution of pores compared to using polyvinyl alcohol cellulose or hydroxypropyl cellulose alone.

[0024] According to some embodiments of the present invention, the mass ratio of polyvinyl alcohol cellulose and hydroxypropyl cellulose in the pore-forming agent is 1 to 1.2:1.

[0025] According to some embodiments of the present invention, the amounts of each component in the raw material include:

[0026] Catalyst waste: 40-50 parts by weight;

[0027] Red mud: 14–22.5 parts by weight;

[0028] Activator: 15-25 parts by weight;

[0029] Adhesive: 4-6 parts by weight;

[0030] Pore-forming agent: 2-4 parts by weight.

[0031] According to some embodiments of the present invention, the mass ratio of the red mud to the catalyst waste is 0.35 to 0.45:1.

[0032] In a second aspect, the present invention provides a method for preparing the catalyst described in the first aspect, comprising: pulverizing catalyst waste and red mud into powder, mixing it with an activator, a binder, and a pore-forming agent, adding water to knead it into shape, and calcining it to obtain the catalyst.

[0033] In this invention, the mixing process of each raw material component can be reasonably adjusted to achieve uniform mixing. For example, after pulverizing catalyst waste and red mud into powder, the two powders are first mixed and stirred for more than 30 minutes; then, they are mixed with other raw materials and kneaded and stirred for 40-50 minutes; water is then added to the mixed material, and stirring continues for 30-50 minutes. In the above mixing process, stirring for too short or too long will cause changes in the material structure.

[0034] According to some embodiments of the present invention, the catalyst waste and red mud are dried prior to the pulverization.

[0035] According to some embodiments of the present invention, the particle size of the powder is 400 to 600 mesh.

[0036] According to some embodiments of the present invention, the ratio of water added to the total mass of raw materials is 0.18 to 0.20 L / kg.

[0037] In this invention, the size or shape of the shaped catalyst can be reasonably adjusted according to the needs of use. For example, the catalyst can be shaped into particles with a diameter of 3 to 10 mm and a length of 5 to 15 mm.

[0038] According to some embodiments of the present invention, an air atmosphere is used during the roasting process.

[0039] According to some embodiments of the present invention, the calcination includes: heating to 200-380°C at a heating rate of 5-8°C / min and holding for 1-5 hours.

[0040] In this invention, the control of the calcination process is also very important. If the heating rate before calcination, the calcination temperature and time exceed the above range, it may damage the structure of the catalyst, causing fluctuations in the catalyst strength and activity, thereby adversely affecting the catalytic performance of the catalyst.

[0041] According to some embodiments of the present invention, the calcination temperature is 300–380°C.

[0042] Thirdly, the present invention provides the application of the catalyst described in the first aspect in the dehydrogenation reaction of ethylbenzene to styrene.

[0043] According to some embodiments of the present invention, the reaction is carried out in a fixed-bed reactor.

[0044] According to some embodiments of the present invention, the reaction comprises: contacting vapors of ethylbenzene and water with an ethylbenzene dehydrogenation catalyst to react and obtain styrene.

[0045] According to some embodiments of the present invention, the reaction pressure is 50–80 kPa; the mass hourly space velocity (WHSV) of ethylbenzene is 1.0–1.5 h⁻¹. -1 The reaction inlet temperature is 550–580℃; the reaction outlet temperature is 600–620℃; the reaction temperature is 580–620℃; and the water ratio (wt) is 1.1–1.5.

[0046] The beneficial effects of this invention are at least as follows:

[0047] (1) The catalyst provided by the present invention reuses two industrial wastes, red mud and catalyst waste, which generates economic benefits and achieves good environmental protection effects.

[0048] (2) The catalyst provided by the present invention has catalytic performance that is basically equivalent to that of conventional Fe-K-Ce-Mo catalysts, and its strength is significantly higher than that of conventional Fe-K-Ce-Mo catalysts. It can be applied to the industrial dehydrogenation of ethylbenzene to styrene reaction.

[0049] (3) The catalyst provided by the present invention has a simple preparation process and is suitable for large-scale industrial production. Detailed Implementation

[0050] To make the technical problem to be solved, the technical solution, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely for illustrating this patent and do not limit the scope of protection of this invention in any way.

[0051] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the reagents used in the following embodiments are conventional biochemical reagents; the raw materials, instruments, and equipment used in the following embodiments can all be obtained commercially or by existing methods; unless otherwise specified, the reagent dosages are those used in routine experimental operations; unless otherwise specified, the experimental methods are conventional methods.

[0052] The materials used in the various embodiments and comparative examples of the present invention are as follows:

[0053] (1) Catalyst waste: GS series catalyst production waste from Shanghai Petrochemical Research Institute Co., Ltd.

[0054] (2) Red mud: The accumulated red mud produced by Guangxi accumulated bauxite mine (moisture content of 13wt% and sodium oxide content of 6wt%).

[0055] (3) Gusperidin powder: Henan Meiluo Industrial Co., Ltd.

[0056] (4) Carboxymethyl cellulose: ALFA, CAS No. 9004-32-4.

[0057] (5) Polyvinyl alcohol cellulose: Shanghai test, CAS No. 9002-89-5.

[0058] (6) Hydroxypropyl cellulose: Wokai, CAS No. 9004-64-2.

[0059] (7) Lime: Yingxin Laboratory, CAS No. 1305-78-8.

[0060] (8) Water glass: Shanghai test, CAS No. 13517-24-3.

[0061] Example 1

[0062] Weigh 16 parts red mud, 40 parts catalyst waste, 2 parts guar gum powder, 3 parts carboxymethyl cellulose, 1.5 parts polyvinyl alcohol cellulose, 1.5 parts hydroxypropyl cellulose, 10 parts lime, 10 parts water glass and 16 parts water.

[0063] Red mud and catalyst waste were separately crushed to 400 mesh in a pulverizer. The crushed powders were then mixed and stirred in a mixer for 30 minutes. Then, guar gum powder, carboxymethyl cellulose, polyvinyl alcohol cellulose, hydroxypropyl cellulose, lime and water glass were added in sequence. After mixing, the mixture was stirred for another 40 minutes. Water was then added and the mixture was stirred for another 40 minutes.

[0064] The above materials were extruded and granulated to obtain particles with a diameter of 3.1 mm and a length of 6 mm. These particles were then placed in a muffle furnace, and the reaction temperature was 380℃, the heating rate was 5℃ / min, and the calcination time was 2 h. The catalyst was obtained after calcination.

[0065] Example 2

[0066] Weigh out 15 parts red mud, 40 parts catalyst waste, 2 parts guar gum powder, 4 parts carboxymethyl cellulose, 1.4 parts polyvinyl alcohol cellulose, 1.6 parts hydroxypropyl cellulose, 10 parts lime, 10 parts water glass and 16 parts water.

[0067] Red mud and catalyst waste were separately crushed to 400 mesh in a pulverizer. The crushed powders were then mixed and stirred in a mixer for 30 minutes. Then, guar gum powder, carboxymethyl cellulose, polyvinyl alcohol cellulose, hydroxypropyl cellulose, lime and water glass were added in sequence. After mixing, the mixture was stirred for another 40 minutes. Water was then added and the mixture was stirred for another 40 minutes.

[0068] The above materials were extruded and granulated to obtain particles with a diameter of 3.1 mm and a length of 6 mm. These particles were then placed in a muffle furnace, and the reaction temperature was 300℃, the heating rate was 8℃ / min, and the calcination time was 5 h. The catalyst was obtained after calcination.

[0069] Example 3

[0070] The catalyst was prepared in accordance with Example 1, except that 16 parts of red mud and 40 parts of catalyst waste were replaced with 13 parts of red mud and 43 parts of catalyst waste.

[0071] Example 4

[0072] The catalyst was prepared in accordance with Example 1, except that 16 parts of red mud and 40 parts of catalyst waste were replaced with 20 parts of red mud and 36 parts of catalyst waste.

[0073] Example 5

[0074] The catalyst was prepared according to Example 1, except that the water content of the accumulated red mud was 12 wt% and the sodium oxide content was 15 wt%.

[0075] Example 6

[0076] The catalyst was prepared according to Example 1, except that the water content of the accumulated red mud was 20 wt% and the sodium oxide content was 5 wt%.

[0077] Example 7

[0078] The catalyst was prepared in accordance with Example 1, except that the reaction temperature after placing the particles in the muffle furnace was 280°C and the heating rate was 5°C / min.

[0079] Example 8

[0080] The catalyst was prepared in accordance with Example 1, except that the reaction temperature after the particles were placed in the muffle furnace was 380°C and the heating rate was 10°C / min.

[0081] Comparative Example 1

[0082] The catalyst was prepared in accordance with Example 1, except that no red mud was added.

[0083] Comparative Example 2

[0084] The catalyst was prepared in accordance with Example 1, except that lime and water glass were not added.

[0085] Catalyst performance evaluation

[0086] (1) Catalyst strength:

[0087] The particle size distribution was measured using the DL3 intelligent particle size analyzer from Dalian Penghui Technology Development Co., Ltd. The test results are shown in Table 1.

[0088] (2) Catalytic performance of the catalyst:

[0089] 100 mL of catalyst was loaded into an isothermal fixed-bed reactor. Deionized water and ethylbenzene were separately metered into a preheating mixer, where they were preheated and mixed into a gaseous state before entering the reactor for reaction. The reactants at the reactor outlet were condensed in water and then analyzed for composition by gas chromatography.

[0090] Ethylbenzene conversion and styrene selectivity are calculated using the following formulas:

[0091]

[0092]

[0093] The evaluation conditions were: reaction pressure 60 kPa (absolute pressure) and ethylbenzene mass hourly space velocity 1.0 h⁻¹. -1 The water ratio is 1.2 (wt), the reaction inlet temperature is 580℃, the reaction outlet temperature is 600℃, and the reaction temperature is 620℃.

[0094] After 48 hours of reaction, the ethylbenzene conversion and styrene selectivity of the catalysts in each example and comparative example were tested, and the results are shown in Table 1.

[0095] Table 1

[0096]

[0097]

[0098] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. An ethylbenzene dehydrogenation catalyst, characterized in that, It is prepared from raw materials including catalyst waste, red mud, activator, binder and pore-forming agent; the catalyst waste is the waste generated during the production process of Fe-K-Ce-Mo catalyst; The red mud has a water content of 13-15 wt% and a sodium oxide content of 6-8 wt%. The amounts of each component in the raw material include: Catalyst waste: 40-50 parts by weight; Red mud: 14–22.5 parts by weight; Activator: 15-25 parts by weight; Adhesive: 4-6 parts by weight; Pore-forming agent: 2-4 parts by weight.

2. The catalyst according to claim 1, characterized in that, The red mud is a deposited type of red mud.

3. The catalyst according to claim 1, characterized in that, The activator includes at least one of lime, desulfurized gypsum, and water glass.

4. The catalyst according to claim 1, characterized in that, The binder includes at least one of guar gum powder, polyethylene, polyvinyl chloride, and carboxymethyl cellulose; And / or, the pore-forming agent includes at least one of polyvinyl alcohol cellulose, polyethylene glycol, and hydroxypropyl cellulose.

5. The catalyst according to any one of claims 1-4, characterized in that, The mass ratio of red mud to catalyst waste is 0.35–0.45:

1.

6. A method for preparing the catalyst according to any one of claims 1-5, characterized in that, include: Catalyst waste and red mud are crushed into powder, then mixed with activator, binder and pore-forming agent, water is added and kneaded into shape, and then calcined to obtain the catalyst.

7. The preparation method according to claim 6, characterized in that, The catalyst waste and red mud are dried before pulverization; And / or, the particle size of the powder is 400 to 600 mesh.

8. The preparation method according to claim 6, characterized in that, The ratio of water added to the total mass of raw materials is 0.18–0.20 L / Kg.

9. The preparation method according to any one of claims 6-8, characterized in that, An air atmosphere is used during the roasting process; And / or, the calcination includes: heating to 200-380°C at a heating rate of 5-8°C / min and holding for 1-5 hours.

10. The preparation method according to claim 9, characterized in that, The roasting temperature is 300–380°C.

11. The application of the catalyst according to any one of claims 1-5 or the catalyst prepared by the preparation method according to any one of claims 6-10 in the dehydrogenation of ethylbenzene to styrene reaction.

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