Ethylbenzene dehydrogenation catalyst, preparation method and application thereof

Abstract

The application discloses an ethylbenzene dehydrogenation catalyst as well as a preparation method and application thereof. The catalyst comprises Fe, K, Ce, Mo and Ca elements, and at least one selected from Ba and Sr; wherein a surface layer of the catalyst contains CO3 2‑ ; in a Raman spectrum of the catalyst, CO3 2‑ characteristic diffraction peak intensity is 10% to 200% of Fe2O3 characteristic diffraction peak intensity. The catalyst is used in an ethylbenzene dehydrogenation reaction for preparing styrene, and has the advantages of high styrene selectivity and high ethylbenzene conversion rate.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of ethylbenzene dehydrogenation catalysts, and particularly relates to an ethylbenzene dehydrogenation catalyst, a preparation method and application thereof. BACKGROUND

[0002] Styrene is an important monomer for polymers, and is mainly used as a monomer for producing synthetic rubber and plastic, including expandable polystyrene, polystyrene and ABS (acrylonitrile-butadiene-styrene) materials. Styrene is mainly prepared by catalytic dehydrogenation of ethylbenzene. In this method, ethylbenzene is used as raw material, and styrene is generated by catalytic dehydrogenation in the presence of steam. The catalyst plays a key role in the production of styrene by dehydrogenation of ethylbenzene, and the performance of the catalyst determines the economy of the dehydrogenation process. Benzene and toluene are the main by-products of the dehydrogenation reaction of ethylbenzene, and reducing the amount of toluene and benzene generated can improve the selectivity of styrene, reduce the material consumption of the device, and increase the economic benefit.

[0003] Most of the existing ethylbenzene dehydrogenation catalysts are mainly Fe-K-Ce series catalysts, in which Fe-K oxides are the main catalysts, and Ce is the main additive, and the catalysts also contain Mg, Mo, W and Ca oxides as structural stabilizers and electronic additives. CN115487833A discloses an ethylbenzene dehydrogenation catalyst, which introduces at least one component of TeO2 and B2O3, In2O3 and Ga2O3 on the basis of Fe-K-Ce-Mo-Ca, and improves the selectivity of styrene in the ethylbenzene dehydrogenation reaction. CN106582689A discloses a technical solution of adding In2O3 on the basis of a Fe-K-Ce-W-Mg-Ca catalyst system, and simultaneously adding at least one of HfO2, Nb2O5 or Ta2O5, which improves the selectivity of the catalyst.

[0004] The catalysts in the prior art have problems of producing too much by-product toluene and benzene, and not high enough selectivity of styrene in the ethylbenzene dehydrogenation reaction to different extents, which leads to increased material consumption and decreased economic benefit. SUMMARY

[0005] The purpose of the present application is to solve the problems of too many by-products and low selectivity of styrene in the application of the ethylbenzene dehydrogenation catalyst in the prior art, and to provide an ethylbenzene dehydrogenation catalyst, a preparation method and application thereof. The catalyst has the advantages of high selectivity of styrene and high conversion rate of ethylbenzene in the reaction of ethylbenzene dehydrogenation to styrene.

[0006] The present application provides an ethylbenzene dehydrogenation catalyst in the first aspect. The catalyst comprises Fe, K, Ce, Mo, Ca elements, and at least one selected from Ba and Sr; wherein the surface layer of the catalyst contains CO3 2- ; and in the Raman spectrum of the catalyst, CO3 2-The intensity of the characteristic diffraction peak is 10% to 200% of the intensity of the characteristic diffraction peak of Fe2O3.

[0007] According to the present application, in the Raman spectrum of the catalyst, the intensity of the CO3 2- The intensity of the characteristic diffraction peak is 10% to 200% of the intensity of the characteristic diffraction peak of Fe2O3. As a non-limiting example, the intensity of the CO3 2- The intensity of the characteristic peak is 15%, 20%, 30%, 40%, 50%, 60%, 70%, 78%, 90%, 100%, 110%, 120%, 130%, 150%, 180%, etc. of the intensity of the characteristic peak of Fe2O3, preferably 80% to 120%.

[0008] According to the present application, the catalyst comprises the following components, on the basis of the mass of the catalyst and in terms of oxides:

[0009] (a) 60% to 83% of Fe2O3;

[0010] (b) 8% to 20% of K2O;

[0011] (c) 4% to 11% of CeO2;

[0012] (d) 0.5% to 5% of MoO3;

[0013] (e) 0.2% to 5% of CaO;

[0014] (f) 0.1% to 2% of BaO and / or SrO.

[0015] According to the present application, it is preferred that the catalyst composition simultaneously comprises Ba and Sr elements. It is further preferred that the mass ratio of BaO to SrO, in terms of oxides, is 0.2 to 3:1, preferably 0.5 to 3:1. Ba and Sr have a synergistic effect on the styrene selectivity and ethylbenzene conversion of the catalyst in the ethylbenzene dehydrogenation reaction.

[0016] The second aspect of the present application provides a preparation method of the ethylbenzene dehydrogenation catalyst, which comprises the following steps:

[0017] The Fe source, K source, Ce source, Mo source, Ca source, and at least one selected from the group consisting of Ba source and / or Sr source, and an optional pore-forming agent are mixed, then dried, shaped, and calcined to obtain the ethylbenzene dehydrogenation catalyst.

[0018] According to the present application, at least one of the metal sources of the catalyst raw material is a metal carbonate. The CO3 2- is derived from the metal carbonate.

[0019] According to the present application, no binder is added in the preparation method of the ethylbenzene dehydrogenation catalyst.

[0020] According to the present application, the forming process can add appropriate amount of water. The water adding method is slow adding, and the amount of water is not particularly limited, which can be adjusted according to the dryness of the material. Preferably, the amount of water added is 15% to 35% of the total weight of the catalyst raw material.

[0021] According to the present application, the forming can adopt extrusion forming, and the strip shape can be a particle with a diameter of 2 to 5 mm and a length of 3 to 10 mm.

[0022] According to the present application, the drying conditions are: temperature of 10 to 90℃, preferably 20 to 60℃; and / or, time of 0.5 to 10h, preferably 1 to 8h; and / or, relative humidity of 50% to 100%, preferably 60% to 99%.

[0023] According to the present application, the calcination conditions are: calcination temperature of 700 to 1000℃, preferably 750 to 950℃; and / or, time of 0.5 to 10h, preferably 2 to 6h.

[0024] According to the present application, the metal source of the catalyst raw material is added in the form of metal salt and / or metal oxide. At least one of the metal sources of the catalyst raw material is a metal carbonate.

[0025] According to the present application, preferably, the Fe source is added in the form of oxide Fe2O3. The Fe source is preferably selected from red iron oxide and / or yellow iron oxide. The K source is potassium carbonate. The Ce source is added in the form of cerium salt; the cerium salt is any one or more of cerium nitrate, cerium oxalate, and cerium carbonate. The Mo source is added in the form of molybdenum salt or oxide, and the molybdenum salt is ammonium molybdate. The Ca source is calcium carbonate. The Ba source is barium carbonate. The Sr source is strontium carbonate. The pore-forming agent includes at least one of activated carbon, graphite, sodium hydroxymethyl cellulose, and polystyrene microspheres. The amount of the pore-forming agent added is 0.01% to 5% of the mass of the metal source. Among them, the metal source is the Fe source, the K source, the Ce source, the Mo source, the Ca source, and at least one selected from the Ba source and the Sr source, and the metal source is calculated as oxide.

[0026] The third aspect of the present application provides the use of the catalyst prepared by the above-mentioned method in the reaction of preparing styrene from ethylbenzene by dehydrogenation.

[0027] According to the present application, the method of the use is: contacting the ethylbenzene-containing raw material with the above-mentioned catalyst in the presence of water vapor to carry out a dehydrogenation reaction, and obtaining a product containing styrene.

[0028] According to the present application, in the reaction, the weight ratio of water to ethylbenzene (referred to as water ratio) is 0.8 to 2.5.

[0029] According to the present application, water is preheated into steam before entering the reactor and is mixed with the raw material gas sufficiently.

[0030] According to the present application, the temperature of the dehydrogenation reaction is 550-640℃.

[0031] According to the present application, the pressure of the dehydrogenation reaction is 20-100kPa in absolute pressure.

[0032] According to the present application, the mass space velocity of ethylbenzene is 0.2-2.0h -1 .

[0033] Compared with the prior art, the present application has significant advantages and outstanding effects, which are as follows:

[0034] 1、The catalyst of the present application comprises Fe, K, Ce, Mo, Ca elements, and at least one element selected from Ba and Sr; wherein the surface layer of the catalyst contains CO3 2- ; in the Raman spectrum of the catalyst, the intensity of the CO3 2- characteristic peak is 10%-200% of the intensity of the Fe2O3 characteristic peak. The selectivity of the Fe-K-Ce series dehydrogenation catalyst is directly related to the properties of the surface layer of the catalyst. The inventors have found that the performance of the catalyst can be improved when the surface layer of the catalyst contains a certain amount of CO3 2- . The CO3 2- in the surface layer of the catalyst adjusts the properties of the catalyst surface, reduces the generation of by-product toluene, and significantly improves the selectivity of styrene and the conversion rate of ethylbenzene in the reaction.

[0035] In the present application, at least one element selected from Ba and Sr is included in the composition of the catalyst, which helps to improve the selectivity of styrene, and the effect is better when both are added together.

[0036] 2、In the present application, at least one metal carbonate is used as the metal source in the preparation method of the catalyst, and specific relative humidity and drying temperature conditions are controlled in the drying process of the preparation method to make the carbonate accumulate on the surface of the catalyst. When the intensity of the CO3 2- characteristic peak in the Raman spectrum is 10%-200% of the intensity of the Fe2O3 characteristic peak, the performance of the catalyst is significantly improved.

[0037] Preferably, the ratio of Ba element to Sr element is limited, and the prepared catalyst has high selectivity. Further, the introduction of barium carbonate and / or strontium carbonate in the preparation process of the catalyst also improves the CO3 2- concentration on the surface layer of the catalyst, and improves the selectivity of styrene and the conversion rate of ethylbenzene.

[0038] 3. The catalyst described in this invention has the advantages of high styrene selectivity and high ethylbenzene conversion rate in the dehydrogenation reaction of ethylbenzene to styrene, achieving excellent technical results.

[0039] Using the technical solution of this invention, the catalyst of this invention is evaluated for activity in an isothermal fixed bed at 50 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (MHSV) of 0.5 h⁻¹. -1 The reaction was evaluated under the following conditions: 600℃ and a water ratio reduced from the usual 2.0 (by weight) to 1.2 (by weight). After 100 hours of reaction, the ethylbenzene conversion reached 76.2%, and the styrene selectivity reached 98.1%. This indicates that the catalyst of the present invention, when used in the dehydrogenation reaction of ethylbenzene to styrene, exhibits high styrene selectivity and good activity, achieving good technical results. Attached Figure Description

[0040] Figure 1 The Raman spectra of the catalysts prepared in Examples 1, 5 and Comparative Example 1 of this invention are shown. Detailed Implementation

[0041] 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.

[0042] In this invention, Raman spectroscopy was measured using a LabRAM Aramis laser from Horiba Jobin Yvon, with a laser wavelength of 532 nm. The Raman spectrum of the catalyst ranges from 1050 to 1075 cm⁻¹. -1 The spectral peaks in the wavelength range are CO3. 2- Characteristic diffraction peaks, 660–680 cm⁻¹ -1 The spectral peaks in the wavelength range are characteristic diffraction peaks of Fe2O3. In the Raman spectrum, CO3... 2- The ratio of the characteristic peak intensity to the characteristic peak intensity of Fe2O3 is, for CO3 2- The ratio of the height of the characteristic diffraction peak to the height of the characteristic diffraction peak of Fe2O3.

[0043] In this invention, relative humidity is defined as the ratio of the partial pressure of water vapor in a gas to the partial pressure of saturated water vapor under certain temperature and pressure conditions. The relative humidity in this invention is measured using a Testo 623 digital temperature and humidity recorder. The drying pressure is atmospheric pressure. The relative humidity test conditions in each example are the temperature and pressure of the catalyst drying environment in a constant humidity oven.

[0044] In the present application, the catalysts of the present application are evaluated for ethylbenzene dehydrogenation reaction performance in a negative pressure isothermal fixed bed, and the process is briefly described as follows:

[0045] The reactor is a stainless steel tube with an inner diameter of 1", and is filled with 50-150 ml of catalyst with a diameter of 3-10 mm. Deionized water and ethylbenzene are respectively input into a preheating mixer through a metering pump, and are mixed into a gaseous state before being input into the reactor. The reactor is heated by an electric heating wire to reach a predetermined temperature. The reaction products flowing out of the reactor are condensed by water and analyzed by a gas chromatograph.

[0046] The ethylbenzene conversion rate and the styrene selectivity are calculated according to the following formula:

[0047]

[0048]

[0049] Styrene yield % = ethylbenzene conversion rate % * styrene selectivity %.

[0050] In the present application, the evaluation conditions of each catalyst are as follows: 100 ml of dehydrogenation catalyst is loaded into the reactor, and the performance is evaluated under the conditions of 50 kPa (absolute pressure), a mass space velocity of ethylbenzene of 0.5 h -1 -1, a reaction temperature of 600°C, and a water ratio of 1.2 (wt), and the test results of 100 h of reaction are listed in Table 1.

[0051] The present application is further described by the following examples, but the protection scope of the present application is not limited by the examples.

[0052] Example 1

[0053] Iron oxide red equivalent to 74.5 parts of Fe2O3, potassium carbonate equivalent to 12.0 parts of K2O, cerium nitrate equivalent to 8.2 parts of CeO2, ammonium molybdate equivalent to 2.6 parts of MoO3, calcium carbonate equivalent to 1.5 parts of CaO, barium carbonate equivalent to 1.2 parts of BaO, and 2.0 parts of sodium hydroxymethyl cellulose are weighed and added into a mixer to be stirred for 2 h until being uniformly mixed. Then, deionized water accounting for 24% of the total weight of the dehydrogenation catalyst raw material is added and mixed for 2 h. Next, the above mixture is extruded and pelletized to obtain particles with a diameter of 3 mm and a length of 6 mm, which are placed in a constant humidity oven for drying at a relative humidity of 70% and a temperature of 65°C for 5 h, and then are placed in a muffle furnace for calcination at 850°C for 4 h to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0054] The Raman spectrum of the catalyst is shown in Figure 1 , and CO3 2- exists on the surface layer of the catalyst. The characteristic diffraction peak of CO3 2- is at 1064 cm -1The characteristic diffraction peak of Fe2O3 is at 668 cm⁻¹. -1 Location; CO3 2- The intensity of the characteristic diffraction peak is 69% of the intensity of the characteristic diffraction peak of Fe2O3.

[0055] Example 2

[0056] Weigh out the following amounts: iron oxide red (equivalent to 60.5 parts Fe2O3), potassium carbonate (equivalent to 19.2 parts K2O), cerium nitrate (equivalent to 10.3 parts CeO2), ammonium molybdate (equivalent to 4.9 parts MoO3), calcium carbonate (equivalent to 5.0 parts CaO), barium carbonate (equivalent to 0.1 parts BaO), and sodium carboxymethyl cellulose (1.0 part). Add these to a mixer and stir for 2 hours until homogeneous. Then add deionized water (equivalent to 18% of the total weight of the dehydrogenation catalyst raw materials) and mix for 2 hours. Next, extrude and granulate the mixture to obtain particles with a diameter of 3 mm and a length of 6 mm. Place these particles in a constant humidity oven and dry them at a relative humidity of 62% and a temperature of 75°C for 5 hours. Then, calcine them in a muffle furnace at 850°C for 4 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0057] Example 3

[0058] Weigh out the following amounts: 82.6 parts of iron oxide red (Fe₂O₃), 8.2 parts of potassium carbonate (K₂O), 4.2 parts of cerium nitrate (CeO₂), 2.9 parts of ammonium molybdate (MoO₃), 0.2 parts of calcium carbonate (CaO), 1.9 parts of barium carbonate (BaO), and 4.0 parts of sodium hydroxymethyl cellulose. Add these to a mixer and stir for 2 hours until homogeneous. Then add 30% (by weight) of deionized water (based on the total weight of the dehydrogenation catalyst raw materials) and mix for 2 hours. Next, extrude and granulate the mixture to obtain particles with a diameter of 3 mm and a length of 6 mm. Place these particles in a constant humidity oven and dry at 82°C and 50% relative humidity for 2 hours. Then, calcine them in a muffle furnace at 850°C for 4 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0059] Example 4

[0060] Weigh out the following amounts: 71.9 parts of iron oxide red (Fe₂O₃), 10.8 parts of potassium carbonate (K₂O), 11.0 parts of cerium nitrate (CeO₂), 0.5 parts of ammonium molybdate (MoO₃), 4.6 parts of calcium carbonate (CaO), 1.2 parts of barium carbonate (BaO), and 0.01 parts of sodium carboxymethyl cellulose. Add these to a mixer and stir for 2 hours until homogeneous. Then add 30% (by weight) of deionized water (based on the total weight of the dehydrogenation catalyst raw materials) and mix for 2 hours. Next, extrude and granulate the mixture to obtain particles with a diameter of 3 mm and a length of 6 mm. Place these particles in a constant humidity oven and dry at 60% relative humidity and 15°C for 8 hours. Then, calcine them in a muffle furnace at 850°C for 4 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0061] Example 5

[0062] Weigh out the following amounts: iron oxide red (equivalent to 74.5 parts Fe2O3), potassium carbonate (equivalent to 12.0 parts K2O), cerium nitrate (equivalent to 8.2 parts CeO2), ammonium molybdate (equivalent to 2.6 parts MoO3), calcium carbonate (equivalent to 1.5 parts CaO), barium carbonate (equivalent to 0.6 parts BaO), strontium carbonate (equivalent to 0.6 parts SrO), and sodium carboxymethyl cellulose. Add these to a mixer and stir for 2 hours until homogeneous. Then add deionized water (equivalent to 24% of the total weight of the dehydrogenation catalyst raw materials) and mix for 2 hours. Next, extrude and granulate the mixture to obtain particles with a diameter of 3 mm and a length of 6 mm. Place these particles in a constant humidity oven and dry them at 90% relative humidity and 50°C for 5 hours. Then, calcine them in a muffle furnace at 850°C for 4 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0063] Raman spectra of the catalyst are as follows Figure 1 As shown. CO3 is present on the surface of the catalyst. 2- CO3 2- The characteristic diffraction peak is at 1064 cm⁻¹ -1 The characteristic diffraction peak of Fe2O3 is at 668 cm⁻¹. -1 Location; CO3 2- The intensity of the characteristic diffraction peak is 112% of the intensity of the characteristic diffraction peak of Fe2O3.

[0064] Example 6

[0065] Weigh out the following amounts: iron oxide red (equivalent to 74.5 parts Fe2O3), potassium carbonate (equivalent to 12.0 parts K2O), cerium nitrate (equivalent to 8.2 parts CeO2), ammonium molybdate (equivalent to 2.6 parts MoO3), calcium carbonate (equivalent to 1.5 parts CaO), barium carbonate (equivalent to 0.6 parts BaO), strontium carbonate (equivalent to 0.6 parts SrO), and sodium carboxymethyl cellulose. Add these to a mixer and stir for 2 hours until homogeneous. Then add deionized water (equivalent to 24% of the total weight of the dehydrogenation catalyst raw materials) and mix for 2 hours. Next, extrude and granulate the mixture to obtain particles with a diameter of 3 mm and a length of 6 mm. Place these particles in a constant humidity oven and dry them at 50°C and 85% relative humidity for 5 hours. Then, calcine them in a muffle furnace at 850°C for 4 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0066] Example 7

[0067] Weigh out the following amounts: iron oxide red (equivalent to 74.5 parts Fe2O3), potassium carbonate (equivalent to 12.0 parts K2O), cerium nitrate (equivalent to 8.2 parts CeO2), ammonium molybdate (equivalent to 2.6 parts MoO3), calcium carbonate (equivalent to 1.5 parts CaO), barium carbonate (equivalent to 0.4 parts BaO), strontium carbonate (equivalent to 0.8 parts SrO), and sodium carboxymethyl cellulose. Add these to a mixer and stir for 2 hours until homogeneous. Then add deionized water (equivalent to 24% of the total weight of the dehydrogenation catalyst raw materials) and mix for 2 hours. Next, extrude and granulate the mixture to obtain particles with a diameter of 3 mm and a length of 6 mm. Place these particles in a constant humidity oven and dry them at 74% relative humidity and 42℃ for 5 hours. Then, calcine them in a muffle furnace at 850℃ for 4 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0068] Example 8

[0069] Weigh out the following amounts: 74.5 parts of iron oxide yellow (Fe₂O₃), 12.0 parts of potassium carbonate (K₂O), 8.2 parts of cerium nitrate (CeO₂), 2.6 parts of ammonium molybdate (MoO₃), 1.5 parts of calcium carbonate (CaO), 0.9 parts of barium carbonate (BaO), 0.3 parts of strontium carbonate (SrO), and 2.0 parts of sodium carboxymethyl cellulose. Add these to a mixer and stir for 2 hours until homogeneous. Then add 24% (by weight) of deionized water (based on the total weight of the dehydrogenation catalyst raw materials) and mix for 2 hours. Next, extrude and granulate the mixture to obtain particles with a diameter of 3 mm and a length of 6 mm. Place these particles in a constant humidity oven and dry at 30°C and 68% relative humidity for 5 hours. Then, calcine them in a muffle furnace at 850°C for 4 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0070] Comparative Example 1

[0071] Weigh out the following amounts: iron oxide red (equivalent to 75.7 parts Fe2O3), potassium nitrate (equivalent to 12.0 parts K2O), cerium nitrate (equivalent to 8.2 parts CeO2), ammonium molybdate (equivalent to 2.6 parts MoO3), calcium hydroxide (equivalent to 1.5 parts CaO), barium nitrate (equivalent to 0.6 parts BaO), strontium nitrate (equivalent to 0.6 parts SrO), and sodium hydroxymethyl cellulose (equivalent to 2.0 parts). Add these to a mixer and stir for 2 hours until homogeneous. Then add deionized water (24% of the total weight of the dehydrogenation catalyst raw materials) and mix for 2 hours. Next, extrude and granulate the mixture to obtain particles with a diameter of 3 mm and a length of 6 mm. Place these particles in a constant humidity oven and dry at 90% relative humidity and 50°C for 5 hours. Then, calcine them in a muffle furnace at 850°C for 4 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1. The Raman spectrum of the catalyst is shown below. Figure 1 As shown.

[0072] Comparative Example 2

[0073] Same as Example 5, except that the drying conditions are 10% relative humidity and 95°C for 3 hours.

[0074] Table 1. Catalyst composition and evaluation results of the examples and comparative examples.

[0075]

[0076]

[0077] The specific 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 combining the 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. An ethylbenzene dehydrogenation catalyst, said catalyst comprising the elements Fe, K, Ce, Mo, Ca, and at least one selected from the group consisting of Ba and Sr; wherein, The surface of the catalyst contains CO3. 2- In the Raman spectrum of the catalyst, CO3 2- The intensity of the characteristic diffraction peak is 10% to 200% of the intensity of the characteristic diffraction peak of Fe2O3; The catalyst comprises the following components, based on the mass of the catalyst and in terms of oxides: (a) 60-83% Fe2O3; (b) 8-20% K2O; (c) 4-11% CeO2; (d) 0.5-5% MoO3; (e) 0.2-5% CaO; (f) 0.1-2% BaO and / or SrO.

2. The catalyst of claim 1, wherein CO3 2- the intensity of the characteristic diffraction peak is 80%~120% of the intensity of the characteristic diffraction peak of Fe2O3.

3. The catalyst of claim 1, wherein The catalyst comprises both Ba and Sr elements; the mass ratio of BaO to SrO, in terms of oxides, is 0.2-3:

1.

4. The catalyst of claim 1 wherein, The catalyst comprises both Ba and Sr elements; the mass ratio of BaO to SrO, in terms of oxides, is 0.5-3:

1.

5. A process for the preparation of the catalyst according to any one of claims 1 to 4, characterized in that, The catalyst comprises: The Fe source, K source, Ce source, Mo source, Ca source, and at least one selected from the Ba source and / or Sr source, and the optional pore-forming agent are mixed, then dried, shaped, and calcined to obtain the ethylbenzene dehydrogenation catalyst; at least one of the metal sources of the catalyst raw materials is a metal carbonate.

6. The preparation method according to claim 5, characterized in that, The drying conditions are: a temperature of 10-90°C; and / or, a time of 0.5-10h; and / or, a relative humidity of 50-100%.

7. The preparation method according to claim 5, characterized in that, The drying conditions are: a temperature of 20-60°C; and / or, a time of 1-8h; and / or, a relative humidity of 60-99%.

8. The preparation method according to claim 5, characterized in that, The calcination conditions are: a calcination temperature of 700-1000°C; and / or, a time of 0.5-10h.

9. The preparation method according to claim 5, characterized in that, The calcination conditions are: a calcination temperature of 750-950°C; and / or, a time of 2-6h.

10. The preparation method according to claim 5, characterized in that, The metal sources of the catalyst raw materials are added in the form of metal salts and / or metal oxides.

11. The preparation method according to claim 10, characterized in that, The Fe source is added in the form of Fe2O3 oxide; and / or, the K source is potassium carbonate; and / or, the Ce source is any one or more of cerium nitrate, cerium oxalate, and cerium carbonate; and / or, the Mo source is ammonium molybdate; and / or, the Ca source is calcium carbonate; and / or, the Ba source is barium carbonate; and / or, the Sr source is strontium carbonate; and / or, the pore-forming agent comprises at least one of activated carbon, graphite, sodium hydroxymethyl cellulose, and polystyrene microspheres.

12. The preparation method according to claim 11, characterized in that, The Fe source is selected from red iron oxide and / or yellow iron oxide.

13. The preparation method according to claim 11, characterized in that, The pore-forming agent is added in an amount of 0.01-5% of the mass of the metal sources.

14. Use of the catalyst according to any one of claims 1-4 or prepared by the method according to any one of claims 5-13 in an ethylbenzene dehydrogenation reaction to prepare styrene.

15. Use according to claim 14, characterized in that, In the reaction, the weight ratio of water to ethylbenzene is 0.8-2.5; and / or, the temperature of the reaction is 550-640 DEG C; and / or, the pressure of the reaction is 20-100 kPa (absolute pressure); and / or, the mass space velocity of ethylbenzene is 0.2-2.0 h -1 .

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