A catalyst for ethylbenzene dehydrogenation adapted to alternating electromagnetic field and a preparation method and application thereof

Abstract

The application discloses a catalyst for ethylbenzene dehydrogenation suitable for alternating electromagnetic field and a preparation method and application thereof, and belongs to the technical field of catalysts.The chemical composition of the catalyst for ethylbenzene dehydrogenation comprises Fe2O3, SiC, Al2O3 and an anti-carbon-deposition additive.The core problems of high energy consumption, poor adaptability, low conversion rate and backward process of the existing catalyst technology for ethylbenzene dehydrogenation are solved through mutual coordination of the components in the catalyst and corresponding processes, and the economic efficiency, greenness and stability are taken into account.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, and particularly relates to a catalyst adapted to alternating electromagnetic fields for the dehydrogenation of ethylbenzene, its preparation method and application. Background Technology

[0002] Ethylbenzene dehydrogenation to styrene is the main commercial production route for styrene, a key monomer in the polymerization industry, with approximately 90% of global styrene production achieved through this process. Currently, the most readily applicable and widely used industrial technology relies primarily on iron-based catalysts, such as the Fe₂O₃-K₂O-Cr₂O₃ / Al₂O₃-based catalytic system. This process typically involves catalytic dehydrogenation at high temperatures (580-630°C), under normal or slightly negative pressure, and with steam dilution. Representative technologies include Lummus / UOP's SMART and BASF's Styro-Plus technologies. Their reactors are mostly adiabatic radial flow fixed-bed reactors. After years of optimization, these iron-based catalysts can achieve 60-70% ethylbenzene conversion and 94-96% styrene selectivity. (Applied Catalysis A: General, 2023, 666: 119372) However, significant problems and defects still exist in the existing technology: First, high-temperature operation leads to high energy consumption and exacerbates side reactions, limiting styrene yield. Ethylbenzene dehydrogenation reactions typically occur above 600°C. While this high-temperature environment is beneficial for increasing the reaction rate, it also accelerates side reactions such as ethylbenzene cracking, aromatization, and deep dehydrogenation. Second, the catalyst's structural stability is insufficient, leading to rapid deactivation. Under high-temperature, long-term operation conditions, potassium ions (K+) in traditional iron-based catalysts... + Ethylbenzene is prone to migration, and the active components may undergo phase transitions. The support material is also susceptible to sintering, leading to agglomeration of the active components and a decrease in the catalyst's specific surface area. Finally, ethylbenzene conversion is limited; constrained by thermodynamic equilibrium, the single-pass conversion rate is difficult to exceed 70%. The large amount of unreacted ethylbenzene circulating increases the equipment load because the hydrogen generated in the reaction cannot be separated in time, pushing the equilibrium towards the reverse reaction direction. Simultaneously, existing membrane separation technologies are difficult to implement on a large industrial scale due to membrane clogging and permeability degradation.

[0003] Therefore, how to provide a catalyst for ethylbenzene dehydrogenation that has low energy consumption, stable structure, and long lifespan is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a catalyst adapted to alternating electromagnetic fields for ethylbenzene dehydrogenation, its preparation method, and its application.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A catalyst for ethylbenzene dehydrogenation adapted to alternating electromagnetic fields, comprising an active component, an electromagnetic field responsive agent, a structural agent, and an anti-coking agent. The active component is Fe2O3; The electromagnetic field response aid is one or more of SiC, BaTiO3, and ZnO; The structural additive is Al2O3.

[0006] Preferably, the chemical composition includes the following mass fractions: Fe2O3 15-25%, SiC 50-60%, Al2O3 10-30% and anti-coking agent 2-7%.

[0007] Preferably, the anti-carbon deposition agent is obtained by compounding CeO2 and La2O3 in a mass ratio of (1-2):1.

[0008] Beneficial effects: The catalyst components in this invention include the main active component (Fe2O3), electromagnetic field responsive aid (SiC), structural aid (Al2O3), and anti-coking aid (a combination of CeO2 and La2O3). The mass fraction of each component is strictly controlled to ensure the electromagnetic field responsiveness, catalytic activity, and stability of the catalyst. SiC, acting as an electromagnetic field response aid, works by efficiently converting electromagnetic field energy into heat energy through semiconductor conductivity loss and dielectric relaxation polarization loss induced by defects / interfaces. It also optimizes the overall impedance matching of the material to promote electromagnetic wave absorption and attenuation, solving the core problem of existing catalysts' inability to respond to electromagnetic fields. The main active component, Fe2O3, provides the core active sites for the ethylbenzene dehydrogenation reaction. In the initial stage of the reaction, Fe2O3 is partially reduced to Fe3O4 by the generated hydrogen, which is the true active phase for the ethylbenzene dehydrogenation reaction. The unsaturated iron sites on the Fe3O4 surface selectively activate the CH bonds of the ethyl group in the ethylbenzene molecule, lowering the activation energy of the dehydrogenation reaction and causing the ethylbenzene molecule to break the CH bonds to generate styrene and hydrogen. The structural aid Al2O3 inhibits catalyst particle agglomeration, increasing the catalyst's specific surface area and mechanical strength. The anti-coking aid is a combination of CeO2 and La2O3; their synergistic effect significantly inhibits coking during the reaction, prolonging catalyst life and further enhancing the catalyst's sensitivity to electromagnetic fields.

[0009] A method for preparing a catalyst adapted to an alternating electromagnetic field for the dehydrogenation of ethylbenzene includes the following steps: According to the chemical composition ratio, the corresponding nitrate raw materials are calculated and weighed, mixed and dissolved in water to obtain a mixed salt solution. After co-precipitation, in-situ composite with electromagnetic aids, aging, washing and calcination, the solution is pulverized to obtain the catalyst for ethylbenzene dehydrogenation.

[0010] Preferably, the coprecipitate is: The pH of the mixed salt solution was adjusted to weakly alkaline, and then heated and stirred in a water bath to co-precipitate.

[0011] Preferably, adjusting the pH to a slightly alkaline state involves slowly adding ammonia water to adjust the pH to 8.5-9.5. The slow dripping rate is 1-2 mL / min; The water bath conditions are: temperature 60-70℃, time 120-180 min.

[0012] Beneficial effects: Unlike the single precipitation conditions in the prior art, the co-precipitation method and its process parameters in this invention can ensure uniform precipitate particles and improve the dispersibility and electromagnetic field response performance of the catalyst.

[0013] Preferably, the aging temperature is 60-70℃ and the time is 24-36h.

[0014] Preferably, the washing is performed until the pH of the washing solution is neutral, and more preferably until the pH of the washing solution is 7.0.

[0015] Beneficial effects: This washing process can prevent impurity ions from affecting catalyst activity and electromagnetic field responsiveness.

[0016] Preferably, the heating rate of the calcination is 5-10°C, first heating to 300°C and holding for 2 hours, then heating to 650-750°C and holding for 4-6 hours at the same rate.

[0017] Beneficial effects: Unlike the single-temperature calcination in the prior art, the programmed temperature calcination process in this invention can ensure that the catalyst forms a stable active phase structure, while improving the dispersibility of electromagnetic field responsive aids and enhancing the synergistic effect between the catalyst and the electromagnetic field.

[0018] Preferably, the pulverization process further includes a molding process: the pulverized catalyst powder is mixed with a binder, water is added to knead it into shape, and then dried to obtain a shaped catalyst for ethylbenzene dehydrogenation.

[0019] Beneficial effects: This molding process can shape the catalyst into different shapes (such as spheres or strips) according to the actual reactor type, so as to facilitate its use.

[0020] Application of a catalyst adapted to alternating electromagnetic fields for ethylbenzene dehydrogenation in the synergistic catalysis of ethylbenzene dehydrogenation under alternating electromagnetic fields.

[0021] An alternating electromagnetic field drive system includes a high-frequency alternating power supply, an electromagnetic coil, a temperature monitoring module, and a power regulation module.

[0022] Preferably, the output frequency of the high-frequency alternating power supply is 1~90kHz and the output power is 5~20kW; the output frequency and output power can be flexibly adjusted. If the output frequency is too high, the energy consumption will increase, and if the output frequency is too low, sufficient eddy current effect and thermal effect will not be generated, and the power supply will not be able to assist.

[0023] The electromagnetic coil is made of copper enameled wire and is wound on the outside of the reactor jacket. The number of coil turns is 3 to 10, and the inner diameter of the coil is 10 to 100 mm. The temperature monitoring module uses a thermocouple sensor embedded inside the reactor to monitor the temperature of the reaction system in real time with an accuracy of ±1℃. It can transmit the temperature signal to the power regulation module. The power regulation module is linked with the high-frequency alternating power supply and the temperature monitoring module, and can automatically adjust the power output according to the temperature of the reaction system to maintain the reaction temperature within the set range.

[0024] Beneficial effects: The working principle of the alternating electromagnetic field drive system in this invention is as follows: A high-frequency alternating power supply generates a high-frequency alternating current, which in turn generates an alternating electromagnetic field through an electromagnetic coil. This electromagnetic field penetrates the reactor jacket and acts on a specialized catalyst inside. The electromagnetic field-responsive promoter within the catalyst, under the influence of the alternating electromagnetic field, assists in providing the endothermic heat required for the ethylbenzene dehydrogenation reaction. Simultaneously, the electromagnetic field promotes the activation of ethylbenzene molecules and the desorption of hydrogen, improving the reaction conversion rate. A heat insulation layer reduces heat loss, ensuring a stable reaction system temperature and preventing temperature fluctuations from affecting catalytic performance and reaction efficiency. The core difference between the alternating electromagnetic field drive system provided by this invention and existing technologies lies in combining the alternating electromagnetic field with the ethylbenzene dehydrogenation reactor. This achieves electromagnetic field-assisted energy supply and reaction promotion, replacing some of the superheated steam and solving the problem of high energy consumption in existing technologies.

[0025] A method for the synergistic catalytic dehydrogenation of ethylbenzene using an alternating electromagnetic field, employing the aforementioned catalyst for ethylbenzene dehydrogenation, wherein the mass hourly space velocity (WHSV) of ethylbenzene is 1.04 h⁻¹. -1 .

[0026] Preferably, it includes the following steps: Using the aforementioned alternating electromagnetic field driving system, the catalyst for ethylbenzene dehydrogenation was filled. The output frequency of the high-frequency alternating power supply was set, and the molar ratio of ethylbenzene to superheated steam during the catalytic process was controlled to be 1:0.6-0.9. The catalyst for ethylbenzene dehydrogenation was layered and filled. The ethylbenzene flow rate was adjusted to 0.01 mL / min. After mixing, the reaction system was preheated to 550-600℃, and the reaction pressure was atmospheric pressure. The temperature of the reaction system was monitored in real time using a temperature detection module with an accuracy of ±1℃. After the ethylbenzene dehydrogenation reaction continued for 1 hour, the single-pass conversion rate of ethylbenzene, the styrene selectivity, and the catalyst lifetime were measured.

[0027] Beneficial effects: In existing technologies, the molar ratio of ethylbenzene to superheated steam is mostly 1:1.1~1.3, and the preheating temperature is 620~640℃. Compared with existing technologies, this invention significantly reduces steam consumption and preheating temperature because the alternating electromagnetic field can assist in energy supply, eliminating the need for a large amount of steam to provide heat. Reducing steam consumption also lowers energy consumption. In this invention, excessively high preheating temperatures can lead to increased catalyst coking, while excessively low temperatures result in insufficient reaction conversion. Excessive ethylbenzene flow rate (or feed rate) increases side reactions, while insufficient flow rate leads to incomplete reaction. In this invention, under the synergistic effect of the catalyst and the alternating electromagnetic field, ethylbenzene undergoes a dehydrogenation reaction to produce styrene and hydrogen, while also generating a small amount of byproducts (such as toluene, benzene, ethylene, etc.).

[0028] Compared with the prior art, the present invention has the following advantages and technical effects: This invention prepares a specialized catalyst adapted to alternating electromagnetic fields, endowing the catalyst with electromagnetic field responsiveness. Combined with an alternating electromagnetic field driving system providing auxiliary heat, and optimized process parameters reducing steam consumption and reaction temperature, this invention achieves the technical effects of reduced energy consumption, increased conversion rate, and extended catalyst lifespan. Specifically, the invention utilizes the electromagnetic field responsive additive SiC to generate eddy current heat and polarization heat under an electromagnetic field to assist in energy supply, replacing part of the superheated steam. Combined with an optimized steam molar ratio (1:0.6~0.9) and preheating temperature (550~600℃), this achieves a 25%~35% reduction in total energy consumption and reduces steam consumption to below 40%, effectively addressing the shortcomings of excessive steam consumption and non-compliance with low-carbon requirements. Furthermore, by optimizing the catalyst composition (a compound electromagnetic field responsive additive, structural additive, and anti-coking additive) and the specialized preparation process, this invention achieves synergistic enhancement of electromagnetic field responsiveness and stability by each component, inhibiting component loss and coking, extending catalyst lifespan to 800~1000 hours, solving the problems of catalyst incompatibility with electromagnetic fields and easy loss, and reducing production costs. Furthermore, this invention activates ethylbenzene molecules and promotes hydrogen desorption through an alternating electromagnetic field. Combined with the high activity of the catalyst, this increases the single-pass conversion rate of ethylbenzene to 78%–85%, reduces the amount of unreacted ethylbenzene recycled by 30%–40%, significantly reduces equipment load, improves production efficiency, and overcomes the limitation of conversion rates that are difficult to exceed 70%. This invention achieves green and efficient production of styrene from ethylbenzene dehydrogenation by synergistic interaction among the components of the catalyst and corresponding processes, integrating the alternating electromagnetic field with the ethylbenzene dehydrogenation process and catalyst preparation into an integrated technology system. This solves the core problems of existing technologies, such as inability to adapt to electromagnetic field driving, high energy consumption, poor catalyst stability, poor compatibility, low conversion rate, and outdated processes. It realizes a green and efficient production process for styrene from ethylbenzene dehydrogenation, balancing economic efficiency, environmental friendliness, and stability. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of an alternating electromagnetic field driven system. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels; Unless otherwise specified, room temperature or normal temperature in the embodiments of the present invention refers to 25±3℃.

[0033] Example 1 A catalyst adapted to alternating electromagnetic fields for the dehydrogenation of ethylbenzene, comprising the following chemical composition per 100g of catalyst: Fe2O3 15g, SiC 50g, Al2O3 28g, CeO2 3.5g, La2O3 3.5g (CeO2:La2O3=1:1).

[0034] A method for preparing a catalyst adapted to an alternating electromagnetic field for the dehydrogenation of ethylbenzene includes the following steps: Calculate and weigh the raw materials Fe(NO3)3·9H2O, Al(NO3)3·9H2O, Ce(NO3)3·6H2O, and La(NO3)3·6H2O according to the above dosage, add 200mL of deionized water, stir at 300r / min for 30min until dissolved, add ammonia water dropwise to adjust pH=8.5, stir in a 60℃ water bath for 120min to carry out co-precipitation reaction, calcine the SiC auxiliary agent powder in air atmosphere at 500℃ for 2h, and then slowly add it to the precursor suspension, stir at a constant temperature of 60℃ for 1h for compounding. The precursor was uniformly loaded onto the porous channels and surface of the auxiliaries. After the reaction was completed, the mixture was aged at 60℃ for 24 hours. The resulting precipitate was then washed to pH 7.0 and dried at 100℃ for 12 hours. It was then placed in a muffle furnace and heated to 300℃ at a rate of 5℃ / min and held for 2 hours. The temperature was then increased to 650℃ at the same rate and held for 4 hours. After calcination, the product was pulverized to 80 mesh, and 1g of guar gum powder was added. The mixture was kneaded into particles with a diameter of 3mm and a length of 5mm and dried at 110℃ for 8 hours to obtain a catalyst for the dehydrogenation of ethylbenzene.

[0035] Example 2 A catalyst adapted to alternating electromagnetic fields for the dehydrogenation of ethylbenzene, comprising the following chemical composition per 100g of catalyst: Fe2O3 25g, SiC 55g, Al2O3 17g, CeO2 2g, La2O3 1g (CeO2:La2O3=2:1).

[0036] A method for preparing a catalyst adapted to an alternating electromagnetic field for the dehydrogenation of ethylbenzene includes the following steps: Calculate and weigh the nitrate raw materials Fe(NO3)3·9H2O, Al(NO3)3·9H2O, Ce(NO3)3·6H2O, and La(NO3)3·6H2O according to the above dosage, add 250mL of deionized water, stir at 400r / min for 30min until dissolved, add ammonia water dropwise to adjust pH=9.0, stir in a 70℃ water bath for 150min to carry out co-precipitation reaction, calcine the SiC auxiliary agent powder in air atmosphere at 500℃ for 2h, and then slowly add it to the precursor suspension, stir at a constant temperature of 60℃ for 1h to compound, so that... The precursor was uniformly loaded onto the porous channels and surface of the auxiliary agent. After the reaction, it was aged at 65℃ for 30h. The resulting precipitate was then washed to pH=7.0 and dried at 100℃ for 14h. It was then placed in a muffle furnace and heated to 300℃ at a programmed rate of 8℃ / min and held for 2h. The temperature was then increased to 700℃ at the same rate and held for 5h. After calcination, the resulting product was pulverized to 100 mesh, and 1.5g of guar gum powder was added. The mixture was kneaded into particles with a diameter of 4mm and a length of 6.5mm and dried at 110℃ for 9h to obtain a catalyst for ethylbenzene dehydrogenation.

[0037] Example 3 A catalyst adapted to alternating electromagnetic fields for the dehydrogenation of ethylbenzene, comprising the following chemical composition per 100g of catalyst: Fe2O3 20g, SiC 60g, Al2O3 15g, CeO2 3g, La2O3 2g (CeO2:La2O3=1.5:1).

[0038] A method for preparing a catalyst adapted to an alternating electromagnetic field for the dehydrogenation of ethylbenzene includes the following steps: Calculate and weigh the raw materials Fe(NO3)3·9H2O, Al(NO3)3·9H2O, Ce(NO3)3·6H2O, and La(NO3)3·6H2O according to the above dosage, add 300 mL of deionized water, stir at 500 r / min for 60 min until dissolved, add ammonia water dropwise to adjust pH to 9.5, stir in a 70℃ water bath for 180 min to carry out a co-precipitation reaction, calcine the SiC auxiliary agent powder in air at 500℃ for 2 h, and then slowly add it to the precursor suspension, stir at a constant temperature of 60℃ for 1 h to composite, so that the precursor... The catalyst was uniformly loaded onto the porous channels and surface of the additive. After the reaction, it was aged at 70℃ for 36h. The resulting precipitate was then washed to pH=7.0 and dried at 100℃ for 16h. It was then placed in a muffle furnace and heated to 300℃ at a programmed rate of 10℃ / min and held for 2h. The temperature was then increased to 750℃ at the same rate and held for 6h. After calcination, the resulting product was pulverized to 120 mesh, 2g of guar gum powder was added, and the mixture was kneaded into particles with a diameter of 5mm and a length of 8mm. The particles were then dried at 110℃ for 10h to obtain a catalyst for ethylbenzene dehydrogenation.

[0039] Comparative Example 1 (without SiC electromagnetic field response additive) A catalyst comprising the following chemical composition by mass: Fe2O3 20g, Al2O3 15g, CeO2 3g, La2O3 2g (CeO2:La2O3=1.5:1).

[0040] A method for preparing a catalyst, wherein the nitrate raw materials Fe(NO3)3·9H2O, Al(NO3)3·9H2O, Ce(NO3)3·6H2O, and La(NO3)3·6H2O are weighed according to the above chemical composition in this comparative example, and the remaining process steps and parameters are the same as in Example 3.

[0041] Comparative Example 2 (using existing conventional catalysts) A catalyst comprising the following chemical composition by mass: Fe2O3 75g, K2CO3 15g and Al2O3 10g.

[0042] A method for preparing a catalyst includes the following steps: Calculate and weigh the nitrate raw materials Fe(NO3)3·9H2O, K2CO3, and Al(NO3)3·9H2O according to the above dosage, add 300mL of deionized water, stir at 500r / min for 60min until dissolved, add ammonia water to adjust pH=9.5, stir in a 70℃ water bath for 180min to carry out coprecipitation reaction, after the reaction is completed, age at 70℃ for 36h, then wash the obtained precipitate to pH=7.0, dry at 100℃ for 16h, then place it in a muffle furnace, heat to 700℃ at a programmed temperature of 2℃ / min and hold for 5h, after calcination, pulverize the obtained product to 120 mesh, add 2g of guar gum powder, knead into particles with a diameter of 5mm and a length of 8mm, dry at 110℃ for 10h to obtain a catalyst for ethylbenzene dehydrogenation.

[0043] Comparative Example 3 (without anti-coking additive) A catalyst comprising the following chemical composition by mass: Fe2O3 20g, SiC 60g, Al2O3 15g.

[0044] A method for preparing a catalyst, wherein the nitrate raw materials Fe(NO3)3·9H2O and Al(NO3)3·9H2O are weighed according to the above chemical composition in this comparative example, and the remaining process steps and parameters are the same as in Example 3.

[0045] Comparative Example 4 A catalyst, differing from Example 3 only in that La2O3 is replaced with an equal mass of CeO2, specifically comprising the following chemical composition per 100g of catalyst: Fe2O3 75g, SiC 10g, Al2O3 10g, CeO2 5g.

[0046] A method for preparing a catalyst, wherein the nitrate raw materials Fe(NO3)3·9H2O, Al(NO3)3·9H2O, and Ce(NO3)3·6H2O are weighed according to the above chemical composition in this comparative example, and the remaining process steps and parameters are the same as in Example 3.

[0047] Comparative Example 5 A catalyst, differing from Example 3 only in that SiC is replaced with an equal mass of BaTiO3, specifically comprising the following chemical composition per 100g of catalyst: Fe2O3 20g, BaTiO3 60g, Al2O3 15g, CeO2 3g, La2O3 2g.

[0048] A method for preparing a catalyst, wherein the nitrate raw materials Fe(NO3)3·9H2O, Al(NO3)3·9H2O, Ce(NO3)3·6H2O, and La(NO3)3·6H2O are weighed according to the above chemical composition in this comparative example, and the remaining process steps and parameters are the same as in Example 3.

[0049] Comparative Example 6 A catalyst, differing from Example 3 only in that SiC is replaced with an equal mass of ZnO, specifically comprising the following chemical composition per 100g of catalyst: Fe2O3 20g, ZnO 60g, Al2O3 15g, CeO2 3g, La2O3 2g.

[0050] A method for preparing a catalyst, wherein the nitrate raw materials Fe(NO3)3·9H2O, Al(NO3)3·9H2O, Ce(NO3)3·6H2O, and La(NO3)3·6H2O are weighed according to the above chemical composition in this comparative example, and the remaining process steps and parameters are the same as in Example 3.

[0051] Application Example 1 An alternating electromagnetic field driven system, with the following structure: Figure 1 As shown, it includes a high-frequency alternating power supply, an electromagnetic coil, a temperature monitoring module, and a power regulation module.

[0052] The electromagnetic coil is made of copper enameled wire and is wound on the outside of the reactor jacket. The temperature monitoring module uses a thermocouple sensor embedded inside the reactor, which can transmit the temperature signal to the power regulation module; The power regulation module is linked with the high-frequency alternating power supply and the temperature monitoring module, and can automatically adjust the power output according to the temperature of the reaction system to keep the reaction temperature within the set range.

[0053] A method for synergistic catalytic dehydrogenation of ethylbenzene using an alternating electromagnetic field driven system is disclosed. Using the aforementioned alternating electromagnetic field driven system, the catalyst obtained in Example 1 for ethylbenzene dehydrogenation is loaded into a quartz tube before the reaction begins. The high-frequency alternating power supply is set to an output frequency of 90 kHz, an output power of 5 kW, a coil with 5 turns, and a coil inner diameter of 5 mm. The molar ratio of ethylbenzene to superheated steam at the same reaction temperature is controlled to 1:0.8 using a flow meter. The catalyst loading amount is 0.5 g, and the catalyst is layered. The ethylbenzene flow rate is 0.01 mL / min. After mixing, the mixture is preheated to 580 °C, and the reaction pressure is atmospheric pressure. The temperature of the reaction system is monitored in real time using a temperature monitoring module with an accuracy of ±1 °C. After the ethylbenzene dehydrogenation reaction continues for 1 hour, the single-pass conversion rate of ethylbenzene, the selectivity of styrene, and the catalyst lifetime are measured.

[0054] Application Example 2-3 A method for the synergistic catalytic dehydrogenation of ethylbenzene using an alternating electromagnetic field driven system differs from Application Example 1 only in that the catalyst for ethylbenzene dehydrogenation obtained in Examples 2-3 (corresponding to Application Examples 2-3) is used. All other process steps and parameters are the same as in Application Example 1.

[0055] Comparative Application Examples 1-6 The only difference from Application Example 1 is that the catalysts obtained in Comparative Examples 1-6 (corresponding to Comparative Application Examples 1-6) for ethylbenzene dehydrogenation are used. All other process steps and parameters are the same as in Application Example 1.

[0056] Compare with Application Example 7 (Driven without Alternating Electromagnetic Field) A method for catalytic dehydrogenation of ethylbenzene differs from Application Example 1 only in that an alternating electromagnetic field drive system is not used. The catalyst for ethylbenzene dehydrogenation obtained in Example 1 is loaded into a quartz tube. The molar ratio of ethylbenzene to superheated steam is controlled at 1:0.8 during the catalytic process, the catalyst loading amount is 0.5 g, and the catalyst is layered. The ethylbenzene flow rate is 0.01 mL / min. After mixing, the mixture is preheated to 580 °C, and the reaction pressure is atmospheric pressure. The temperature of the reaction system is monitored in real time with an accuracy of ±1 °C. After the ethylbenzene dehydrogenation reaction continues for 1 hour, the single-pass conversion of ethylbenzene, the styrene selectivity, and the catalyst lifetime are measured.

[0057] Technical effects: 1. The ethylbenzene single-pass conversion, styrene selectivity, and catalyst lifetime of the catalysts obtained using gas chromatography corresponding to Application Examples 1-3 and Comparative Application Examples 1-4 were detected and calculated, including the following steps: (1) Calculation basis and parameter setting Based on the conventional industrial ethylbenzene dehydrogenation process (Comparative Application Example 2), and compared with Application Example 3 of the present invention, the single-pass conversion rate of ethylbenzene in Comparative Application Example 2 was 65.8%, the ethylbenzene / steam molar ratio was 1:1.3, and the reaction temperature was 630℃. In Application Example 3, the single-pass conversion rate of ethylbenzene X1 = 84.8%, the ethylbenzene / vapor molar ratio is 1:0.6, and the reaction temperature is 550-600℃; Comparative application example 2: Overall energy consumption composition: steam heating 75%, product separation 15%, raw material preheating 10%; Induction heating energy utilization rate η e =85%, comprehensive thermal utilization rate of steam system η s =35%.

[0058] (2) Calculation of raw material and steam consumption per unit product The calculation is based on the production of 1 mol of styrene.

[0059] (2-1) Ethylbenzene feed rate Compare with application example 2: ; Application Example 3: ; Ethylbenzene feed reduction ratio: ; (2-2) Steam consumption Compare with application example 2: .

[0060] Application Example 3: ; Steam consumption reduction percentage: .

[0061] (3) Contribution of energy consumption reduction by sub-item (3-1) Contribution of Steam Heating to Reduce Energy Consumption Steam energy consumption accounts for 75% of total traditional energy consumption. ; (3-2) Contribution of reduced energy consumption from raw material preheating The total feed rate decreased by 46.0%, and the preheating temperature dropped from 630℃ to 575℃, a temperature decrease of 8.7%. Preheating energy consumption accounts for 10% of the total traditional energy consumption: .

[0062] (3-3) Contribution of separation cycle energy consumption reduction The amount of unreacted ethylbenzene recycled was reduced by 65.5%, and the separation energy consumption accounted for 15% of the total traditional energy consumption. .

[0063] (4) The total theoretical energy consumption is reduced. .

[0064] (5) Deducting the additional energy consumption from electromagnetic fields The additional electrical energy consumption from alternating electromagnetic field-assisted heating is equivalent to 18%-28% of the traditional total energy consumption, resulting in a net reduction in energy consumption. Considering industrial-scale heat loss and efficiency fluctuations, the actual total energy consumption in Application Example 3 is reduced by 25%-35%.

[0065] (6) Verification of the proportion of steam consumption Steam consumption in Application Example 3 was 35.8% of that in Comparative Application Example 2, accounting for a percentage of the total energy consumption in Application Example 3. Steam consumption has been reduced to below 40%, meeting the requirements for low-carbon production.

[0066] In the above formula, X0: the single-pass conversion rate of ethylbenzene compared to Example 2, % X1: Ethylbenzene single-pass conversion rate in Application Example 3, % : Molar amount of ethylbenzene feed, in mol; Molar amount of water vapor, in mol; The contribution of reduced energy consumption from steam, preheating, and separation processes was % %. Theoretical total energy consumption reduction percentage, % The percentage reduction in net energy consumption after deducting electromagnetic energy consumption, % η e Electromagnetic field power utilization rate, % ηs: Thermal efficiency of the steam system, %.

[0067] The results are shown in Table 1:

[0068] It can be seen that the effects of Application Examples 1-3 are significantly better than those of Comparative Application Examples 1-7. The catalyst obtained in Comparative Example 1, lacking the SiC promoter, cannot respond to the electromagnetic field; Comparative Application Example 2, using the traditional catalyst from Comparative Example 2, cannot adapt to the electromagnetic field and exhibits poor stability; the catalyst obtained in Comparative Example 3 has poor stability due to the absence of an anti-coking promoter. Comparative Example 4 verifies the synergistic effect of the CeO2-La2O3 composite anti-coking promoter; Comparative Examples 5 and 6 verify the irreplaceability of SiC; the catalyst obtained in Comparative Application Example 7, lacking electromagnetic field drive, requires a return to high steam usage. The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A catalyst adapted to alternating electromagnetic fields for the dehydrogenation of ethylbenzene, characterized in that, The chemical composition includes active components, electromagnetic field responsive agents, structural agents, and anti-coking agents; The active component is Fe2O3; The electromagnetic field response aid is one or more of SiC, BaTiO3, and ZnO; The structural additive is Al2O3.

2. The catalyst for ethylbenzene dehydrogenation adapted to an alternating electromagnetic field according to claim 1, characterized in that, Chemical composition including the following mass fractions: Fe2O3 15-25%, SiC 50-60%, Al2O3 10-30% and anti-coking agent 2-7%.

3. The catalyst for ethylbenzene dehydrogenation adapted to an alternating electromagnetic field according to claim 2, characterized in that, The anti-carbon deposition additive is obtained by compounding CeO2 and La2O3 in a mass ratio of (1-2):

1.

4. A method for preparing a catalyst for ethylbenzene dehydrogenation adapted to an alternating electromagnetic field as described in any one of claims 1-3, characterized in that, Includes the following steps: According to the chemical composition ratio, the corresponding nitrate raw materials are calculated and weighed, mixed and dissolved in water to obtain a mixed salt solution. After co-precipitation, in-situ composite with electromagnetic aids, aging, washing and calcination, the solution is pulverized to obtain the catalyst for ethylbenzene dehydrogenation.

5. The preparation method according to claim 4, characterized in that, The coprecipitate is: The pH of the mixed salt solution was adjusted to weakly alkaline, and then heated and stirred in a water bath to co-precipitate.

6. The preparation method according to claim 4, characterized in that, The aging temperature is 60-70℃, and the time is 24-36h.

7. The preparation method according to claim 4, characterized in that, The heating rate for the roasting process is 5-10°C. First, the temperature is programmed to rise to 300°C and held for 2 hours, then the temperature is raised to 650-750°C at the same rate and held for 4-6 hours.

8. The preparation method according to claim 4, characterized in that, The process after pulverization also includes a molding process: the pulverized catalyst powder is mixed with a binder, water is added to knead it into shape, and then dried to obtain a shaped catalyst for ethylbenzene dehydrogenation.

9. The application of a catalyst adapted to an alternating electromagnetic field for ethylbenzene dehydrogenation as described in any one of claims 1-3 in the synergistic catalytic dehydrogenation of ethylbenzene in an alternating electromagnetic field.

10. A method for the synergistic catalytic dehydrogenation of ethylbenzene using an alternating electromagnetic field, characterized in that, The catalyst for ethylbenzene dehydrogenation adapted to an alternating electromagnetic field as described in any one of claims 1-3 is used.

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