Catalysts for the dehydrogenation of ethylbenzene to styrene, their preparation methods and applications

Abstract

This invention discloses a catalyst for the dehydrogenation of ethylbenzene to styrene, its preparation method, and its application. The catalyst comprises Fe, K, Ce, Mo, alkaline earth metals, carbon, and at least one element selected from Cl and Br. When used in the ethylbenzene dehydrogenation reaction, this catalyst can significantly improve styrene selectivity while maintaining a high conversion rate of ethylbenzene.

Description

Technical Field

[0001] This invention belongs to the field of ethylbenzene dehydrogenation catalysts, specifically relating to a catalyst for the dehydrogenation of ethylbenzene to styrene, its preparation method, and its application. Background Technology

[0002] Styrene is an important bulk chemical raw material, mainly used as a monomer in the production of synthetic rubber and plastics, including expandable polystyrene, polystyrene, and ABS (acrylonitrile-butadiene-styrene). Styrene has a wide range of applications and its demand is growing rapidly, driving the rapid development of the styrene industry.

[0003] The main methods for producing styrene are the ethylbenzene catalytic dehydrogenation process and the styrene-propylene oxide co-production process. The ethylbenzene catalytic dehydrogenation process uses ethylbenzene as a raw material, catalytically dehydrogenating it in the presence of steam to produce styrene, accounting for approximately 85 wt% of styrene production capacity.

[0004] In recent years, with the large-scale release of styrene production capacity, styrene prices have come under pressure, placing higher demands on the economic efficiency of the styrene production process. For the important petrochemical catalytic process of ethylbenzene dehydrogenation to styrene, the catalyst plays a crucial role in styrene production, and its performance largely determines the economic efficiency of the ethylbenzene dehydrogenation production unit.

[0005] Most existing ethylbenzene dehydrogenation catalysts are based on the Fe-K-Ce series, with Fe-K oxides as the main active components and Ce oxides as the main promoters. Other metal oxides are also included as structural stabilizers or electronic aids. CN101279269A discloses a catalyst that adds bismuth oxide and beryllium oxide to an iron-potassium-cerium-tungsten-calcium catalytic system, improving the activity of the ethylbenzene dehydrogenation catalyst. CN106582689A discloses a technical solution that adds In2O3 to a Fe-K-Ce-W-Mg-Ca catalyst system, along with at least one of HfO2, Nb2O5, or Ta2O5, which improves catalyst selectivity. However, existing methods for producing styrene from ethylbenzene dehydrogenation still suffer from insufficient styrene selectivity.

[0006] The catalysts reported above, when applied to the ethylbenzene dehydrogenation reaction, suffer from problems to varying degrees, including a high number of reaction byproducts and low styrene selectivity. Therefore, developing a suitable catalyst for ethylbenzene dehydrogenation is of great significance. Summary of the Invention

[0007] To address the problems of numerous byproducts and low styrene selectivity in existing ethylbenzene dehydrogenation catalyst applications, this invention provides a catalyst for the dehydrogenation of ethylbenzene to styrene, its preparation method, and its application. This catalyst, when used in the ethylbenzene dehydrogenation reaction, can maintain a high conversion rate of ethylbenzene while significantly improving styrene selectivity.

[0008] A first aspect of the present invention provides a catalyst for the dehydrogenation of ethylbenzene to styrene. The catalyst comprises Fe, K, Ce, Mo, alkaline earth metals, carbon, and at least one element selected from Cl and Br.

[0009] According to the present invention, preferably, the carbon is carbon deposits.

[0010] According to the present invention, the carbon in the catalyst is further introduced by chemical vapor deposition. Specifically, after preparing a catalyst precursor including Fe, K, Ce, Mo, alkaline earth metal elements, and elements selected from Cl and Br by conventional methods, carbon is introduced into the catalyst composition by chemical vapor deposition of the catalyst precursor.

[0011] According to the present invention, the catalyst comprises, by weight, the following components:

[0012] (a) 60–85 parts of Fe2O3;

[0013] (b) 8–18 parts of K2O;

[0014] (c) 4 to 11 parts of CeO2;

[0015] (d) 0.5 to 5 parts of MoO3;

[0016] (e) 0.2 to 6 parts of alkaline earth metal oxides;

[0017] (f) 0.1 to 1 part of Cl and / or Br;

[0018] (g) 0.01 to 10 parts of carbon.

[0019] According to the present invention, in the composition of the catalyst, the metal elements are calculated as oxides, Cl and / or Br are calculated as the elements themselves, and carbon is calculated as carbon elements themselves.

[0020] According to the present invention, the catalyst contains 0.1 to 5 parts by weight of carbon.

[0021] According to the present invention, the weight ratio of component (f) Cl and / or Br and component (g) carbon in the catalyst is further 0.05 to 30:1, preferably 0.10 to 0.35. The two components have a synergistic effect, which can significantly improve the selectivity of the catalyst in the dehydrogenation of ethylbenzene to styrene.

[0022] According to the present invention, the catalyst contains Cl and / or Br elements, preferably Cl and Br; further, the weight ratio of Cl to Br is 1:2 to 5:1.

[0023] According to the present invention, the alkaline earth metal is selected from Ca and / or Mg, preferably Ca.

[0024] A second aspect of the present invention provides a method for preparing the above-mentioned catalyst. The preparation method includes the following steps:

[0025] A catalyst precursor is obtained by mixing Fe source, K source, Ce source, Mo source, alkaline earth metal source and optional pore-forming agent, as well as at least one of Cl source and Br source, and then calcining the mixture after molding; the precursor is then used to introduce carbon elements to obtain the catalyst.

[0026] According to the present invention, the precursor is subjected to chemical vapor deposition to introduce carbon elements to obtain the catalyst.

[0027] According to the present invention, the gas used in the chemical vapor deposition process is one or more selected from alkanes, alkenes, and alkynes. Further, the gas includes at least one selected from ethane, ethylene, and acetylene. The mass hourly space velocity (HSV) of the gas is 1–100 h⁻¹. -1 .

[0028] According to the present invention, the processing temperature in the chemical vapor deposition is 700-1000°C and the time is 1-48h.

[0029] According to the present invention, no binder is added during the preparation of the catalyst.

[0030] According to the present invention, the amount of the pore-forming agent is 0.01% to 5% of the total weight of the catalyst raw materials.

[0031] According to the present invention, an appropriate amount of water can be added during the kneading process. The water is added slowly, and there is no particular limitation on the amount of water added. It can be adjusted according to the dryness or wetness of the materials. Generally, the amount of water added accounts for 15% to 35% of the total mass of the mixture.

[0032] According to the present invention, the molding can be carried out by extrusion molding, and the strip can be a particle with a diameter of 2 to 5 mm and a length of 3 to 10 mm.

[0033] According to the present invention, the calcination conditions are as follows: the calcination temperature is 600-1000℃, and the calcination time is 2-24h.

[0034] According to the present invention, the shaped material may undergo a drying step before calcination. The drying temperature is 30–200°C, and the drying time is 1–24 hours.

[0035] According to the present invention, the Fe source is selected from Fe oxides, preferably iron oxide red and / or iron oxide yellow. The K source is selected from potassium salts, preferably one or more of potassium carbonate, potassium nitrate, and potassium bicarbonate. The Ce source is selected from cerium salts, preferably one or more of cerium nitrate, cerium oxalate, and cerium carbonate. The Mo source is selected from molybdenum salts and / or molybdenum oxides, preferably one or more of ammonium molybdate and molybdenum oxide. The alkaline earth metal source is selected from one or more of alkaline earth oxides and alkaline earth metal hydroxides. The Cl source is selected from HCl. The Br source is selected from HBr. The pore-forming agent is selected from one or more of activated carbon, graphite, sodium carboxymethyl cellulose, and polystyrene microspheres.

[0036] The third aspect of the present invention provides the application of the above-described catalyst or the catalyst prepared by the above-described method in the dehydrogenation reaction of ethylbenzene to styrene.

[0037] According to the present invention, the method of application is as follows: the ethylbenzene-containing raw material is contacted with the catalyst of the present invention in the presence of water vapor to carry out a dehydrogenation reaction, thereby obtaining a styrene-containing product.

[0038] According to the present invention, water is preheated into steam and fully mixed with the feed gas before entering the reactor.

[0039] According to the present invention, the reaction temperature is 550–640°C.

[0040] According to the present invention, the pressure of the reaction is an absolute pressure, 20 to 100 kPa.

[0041] According to the present invention, the mass hourly space velocity (MSV) of ethylbenzene is 0.2–2.0 h⁻¹. -1 .

[0042] Compared with the prior art, the present invention has significant advantages and outstanding effects, as follows:

[0043] 1. In this invention, the selectivity of the Fe-K-Ce dehydrogenation catalyst is directly related to the catalyst composition and the properties of the catalyst surface. The inventors discovered that when the catalyst composition includes Cl and / or Br elements, and the catalyst surface contains a certain amount of carbon, the two elements have a synergistic effect that can significantly improve the catalyst selectivity. The carbon on the catalyst surface regulates the catalyst surface properties, covering some active sites where side reactions occur. The Cl and / or Br elements further passivate the uncovered active sites of side reactions, greatly reducing the formation of byproducts and significantly improving the styrene selectivity of the catalyst.

[0044] 2. In this invention, the catalyst preparation method involves uniformly mixing raw materials containing each component, molding, and calcining to obtain a catalyst precursor. Carbon is introduced into the precursor to obtain the catalyst; preferably, carbon is introduced into the precursor via chemical vapor deposition. After chemical vapor deposition treatment, the catalyst surface contains an appropriate amount of carbon. The catalyst composition includes Cl and / or Br elements, and the presence of a certain amount of carbon deposits on the catalyst surface has a synergistic effect, which can maintain a high ethylbenzene conversion rate while significantly improving the selectivity of styrene.

[0045] 3. The catalyst of this invention is used in the dehydrogenation of ethylbenzene to prepare styrene. It exhibits high selectivity under high catalytic activity and achieves good technical results.

[0046] Using the technical solution of this invention, the catalyst of this invention is evaluated for activity in an isothermal fixed bed at 55 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (MHSV) of 0.5 h⁻¹. -1 The catalyst was evaluated under the following conditions: 600℃ and a water ratio reduced from the usual 2.0 (by weight) to 1.2 (by weight). The ethylbenzene conversion rate reached 75.2%, and the styrene selectivity reached 97.8%. This indicates that the catalyst of this invention, when used in the dehydrogenation reaction of ethylbenzene to styrene, exhibits high styrene selectivity and good activity, achieving excellent technical results. Attached Figure Description

[0047] Figure 1 The Raman spectra of the catalysts prepared in Examples 1, 6 and Comparative Example 1 of this invention are shown. Detailed Implementation

[0048] In this invention, chemical vapor deposition refers to the process of generating solid deposits by reacting gaseous substances on the surface of a catalyst.

[0049] In this invention, the amount of carbon deposited on the catalyst was tested using a Vario EL III elemental analyzer, operating mode: CHN; decomposition temperature: 1000℃.

[0050] 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 shows a wavelength of 1330 ± 15 cm⁻¹. -1 and 1580±15cm -1 The peak at that position is the characteristic carbon diffraction peak of the catalyst.

[0051] In this invention, the performance of the catalyst in the ethylbenzene dehydrogenation reaction was evaluated in a negative pressure isothermal fixed bed. The process is briefly described below:

[0052] The reactor is a 1” stainless steel tube filled with 50–150 mL of catalyst with a diameter of 3–10 mm. Deionized water and ethylbenzene are separately metered into a preheating mixer, preheated and mixed into a gaseous state before entering the reactor. The reactor is heated by an electric heating wire to reach a predetermined temperature. The reactants flowing out of the reactor are condensed in water and their composition is analyzed by gas chromatography.

[0053] Ethylbenzene conversion and styrene selectivity are calculated using the following formulas:

[0054]

[0055]

[0056] Styrene yield % = Ethylbenzene conversion % * Styrene selectivity %.

[0057] The present invention will be further illustrated by the following embodiments, but the scope of protection of the present invention is not limited by the embodiments.

[0058] Example 1

[0059] Weigh out 72.0 parts of iron oxide red (Fe₂O₃), 0.4 parts of HCl (Cl), and 0.2 parts of HBr (Br) and stir in a mixer. Then weigh out 11.0 parts of potassium carbonate (K₂O), 9.6 parts of cerium nitrate (CeO₂), 3.2 parts of ammonium molybdate (MoO₃), 3.6 parts of calcium hydroxide (CaO), and 2 parts of sodium carboxymethyl cellulose. Add these to the 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. Dry these particles in an oven at 60°C for 5 hours, then calcine them in a muffle furnace at 800°C for 4 hours to obtain the dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1. Then, use a mass hourly space velocity (MHSV) of 50 h⁻¹. -1 Acetylene was used to treat the catalyst at 850℃ for 10 h.

[0060] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 55 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂S) of 0.5 h⁻¹. -1 The performance was evaluated under the conditions of reaction temperature 600℃ and water ratio 1.2 (wt), and the test results of the reaction are listed in Table 1.

[0061] Example 2

[0062] Weigh out 63.0 parts of iron oxide red (Fe₂O₃), 0.2 parts of HCl (Cl), and 0.1 parts of HBr (Br) and stir in a mixer. Then weigh out 18.0 parts of potassium carbonate (K₂O), 8.0 parts of cerium nitrate (CeO₂), 4.8 parts of ammonium molybdate (MoO₃), 5.9 parts of calcium hydroxide (CaO), and 2 parts of sodium carboxymethyl cellulose. Add these to the mixer and stir for 2 hours until homogeneous. Then add 28% (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. Dry these particles in an oven at 40°C for 10 hours, then calcine them in a muffle furnace at 750°C for 8 hours to obtain the dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1. Then, use a mass hourly space velocity (MSV) of 50 h⁻¹. -1 Acetylene was used to treat the catalyst at 850℃ for 10 h.

[0063] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 55 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂S) of 0.5 h⁻¹. -1 The performance was evaluated under the conditions of reaction temperature 600℃ and water ratio 1.2 (wt), and the test results of the reaction are listed in Table 1.

[0064] Example 3

[0065] Weigh out 73.0 parts of iron oxide red (Fe₂O₃), 0.3 parts of HCl (Cl), and 0.4 parts of HBr (Br) and stir in a mixer. Then weigh out 12.0 parts of potassium carbonate (K₂O), 11.0 parts of cerium nitrate (CeO₂), 1.4 parts of ammonium molybdate (MoO₃), 1.9 parts of calcium hydroxide (CaO), and 2 parts of sodium carboxymethyl cellulose. Add these to the mixer and stir for 2 hours until homogeneous. Then add 20% (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. Dry these particles in an oven at 100°C for 4 hours, then calcine them in a muffle furnace at 950°C for 3 hours to obtain the dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1. Then, use a mass hourly space velocity (MHSV) of 50 h⁻¹. -1 Acetylene was used to treat the catalyst at 850℃ for 10 h.

[0066] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 55 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂S) of 0.5 h⁻¹. -1 The performance was evaluated under the conditions of reaction temperature 600℃ and water ratio 1.2 (wt), and the test results of the reaction are listed in Table 1.

[0067] Example 4

[0068] Weigh out 84.6 parts of iron oxide red (Fe₂O₃), 0.1 parts of HCl (Cl), and 0.1 parts of HBr (Br) and stir in a mixer. Then weigh out 8.0 parts of potassium carbonate (K₂O), 6.5 parts of cerium nitrate (CeO₂), 0.5 parts of ammonium molybdate (MoO₃), 0.2 parts of calcium hydroxide (CaO), and 2 parts of sodium carboxymethyl cellulose and add them to the mixer. 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. Dry the particles in an oven at 60 °C for 5 hours, then calcine them in a muffle furnace at 850 °C for 4 hours to obtain the dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1. Then, use a mass hourly space velocity (MSV) of 50 h⁻¹. -1 Acetylene was used to treat the catalyst at 850℃ for 10 h.

[0069] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 55 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂S) of 0.5 h⁻¹. -1 The performance was evaluated under the conditions of reaction temperature 600℃ and water ratio 1.2 (wt), and the test results of the reaction are listed in Table 1.

[0070] Example 5

[0071] Weigh out 72.0 parts of iron oxide red (Fe₂O₃), 0.4 parts of HCl (Cl), and 0.2 parts of HBr (Br) and stir in a mixer. Then weigh out 11.0 parts of potassium carbonate (K₂O), 9.6 parts of cerium nitrate (CeO₂), 3.2 parts of ammonium molybdate (MoO₃), 3.6 parts of magnesium hydroxide (MgO), and 2 parts of sodium carboxymethyl cellulose. Add these to the 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. Dry these particles in an oven at 60°C for 5 hours, then calcine them in a muffle furnace at 800°C for 4 hours to obtain the dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1. Then, use a mass hourly space velocity (MHSV) of 50 h⁻¹. -1 Acetylene was used to treat the catalyst at 850℃ for 10 h.

[0072] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 55 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂S) of 0.5 h⁻¹. -1 The performance was evaluated under the conditions of reaction temperature 600℃ and water ratio 1.2 (wt), and the test results of the reaction are listed in Table 1.

[0073] Example 6

[0074] Weigh out 72.0 parts of iron oxide red (Fe₂O₃), 0.4 parts of HCl (Cl), and 0.2 parts of HBr (Br) and stir in a mixer. Then weigh out 11.0 parts of potassium carbonate (K₂O), 9.6 parts of cerium nitrate (CeO₂), 3.2 parts of ammonium molybdate (MoO₃), 3.6 parts of calcium hydroxide (CaO), and 2 parts of sodium carboxymethyl cellulose. Add these to the 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. Dry these particles in an oven at 60°C for 5 hours, then calcine them in a muffle furnace at 800°C for 4 hours to obtain the dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1. Finally, use a mass hourly space velocity (MSH) of 2 h⁻¹. -1 The catalyst was treated with ethane at 720°C for 1 hour.

[0075] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 55 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂S) of 0.5 h⁻¹. -1 The performance was evaluated under the conditions of reaction temperature 600℃ and water ratio 1.2 (wt), and the test results of the reaction are listed in Table 1.

[0076] Example 7

[0077] Weigh out 72.0 parts of iron oxide red (Fe₂O₃), 0.4 parts of HCl (Cl), and 0.2 parts of HBr (Br) and stir in a mixer. Then weigh out 11.0 parts of potassium carbonate (K₂O), 9.6 parts of cerium nitrate (CeO₂), 3.2 parts of ammonium molybdate (MoO₃), 3.6 parts of calcium hydroxide (CaO), and 2 parts of sodium carboxymethyl cellulose. Add these to the 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. Dry these particles in an oven at 60°C for 5 hours, then calcine them in a muffle furnace at 800°C for 4 hours to obtain the dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1. Then, use a mass hourly space velocity (MSV) of 100 h⁻¹. -1 Acetylene was used to treat the catalyst at 980℃ for 40 h.

[0078] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 55 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂S) of 0.5 h⁻¹. -1 The performance was evaluated under the conditions of reaction temperature 600℃ and water ratio 1.2 (wt), and the test results of the reaction are listed in Table 1.

[0079] Example 8

[0080] Weigh out 72.0 parts of iron oxide red (Fe₂O₃) and 0.6 parts of HBr (Br) and stir in a mixer. Then weigh out 11.0 parts of potassium carbonate (K₂O), 9.6 parts of cerium nitrate (CeO₂), 3.2 parts of ammonium molybdate (MoO₃), 3.6 parts of calcium hydroxide (CaO), and 2 parts of sodium carboxymethyl cellulose. Add these to the 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. Dry these particles in an oven at 60°C for 5 hours, then calcine them in a muffle furnace at 800°C for 4 hours to obtain the dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1. Then, use a mass hourly space velocity (MSV) of 60 h⁻¹. -1 The catalyst was treated with ethylene at 950°C for 20 h.

[0081] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 55 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂S) of 0.5 h⁻¹. -1 The performance was evaluated under the conditions of reaction temperature 600℃ and water ratio 1.2 (wt), and the test results of the reaction are listed in Table 1.

[0082] Comparative Example 1

[0083] Weigh out the following amounts: iron oxide red (equivalent to 72.0 parts Fe2O3), potassium carbonate (equivalent to 11.0 parts K2O), cerium nitrate (equivalent to 9.6 parts CeO2), ammonium molybdate (equivalent to 3.2 parts MoO3), calcium hydroxide (equivalent to 3.6 parts CaO), and sodium carboxymethyl cellulose (2 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 an oven and dry at 60°C for 5 hours. Then, calcine them in a muffle furnace at 800°C for 4 hours to obtain the dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0084] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 55 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂S) of 0.5 h⁻¹. -1 The performance was evaluated under the conditions of reaction temperature 600℃ and water ratio 1.2 (wt), and the test results of the reaction are listed in Table 1.

[0085] Comparative Example 2

[0086] Weigh out 72.0 parts of iron oxide red (Fe₂O₃), 0.4 parts of HCl (Cl), and 0.2 parts of HBr (Br) and stir in a mixer. Then weigh out 11.0 parts of potassium carbonate (K₂O), 9.6 parts of cerium nitrate (CeO₂), 3.2 parts of ammonium molybdate (MoO₃), 3.6 parts of calcium hydroxide (CaO), and 2 parts of sodium carboxymethyl cellulose. Add these to the 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 an oven and dry at 60 °C for 5 hours. Then, calcine them in a muffle furnace at 800 °C for 4 hours to obtain the dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0087] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 55 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂S) of 0.5 h⁻¹. -1 The performance was evaluated under the conditions of reaction temperature 600℃ and water ratio 1.2 (wt), and the test results of the reaction are listed in Table 1.

[0088] Comparative Example 3

[0089] Weigh out the following amounts: iron oxide red (equivalent to 72.0 parts Fe2O3), potassium carbonate (equivalent to 11.0 parts K2O), cerium nitrate (equivalent to 9.6 parts CeO2), ammonium molybdate (equivalent to 3.2 parts MoO3), calcium hydroxide (equivalent to 3.6 parts CaO), and sodium carboxymethyl cellulose (2 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. Dry these particles in an oven at 60°C for 5 hours, then calcine them in a muffle furnace at 800°C for 4 hours to obtain the dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1. Then, use a mass hourly space velocity (MHSV) of 50 h⁻¹. -1 Acetylene was used to treat the catalyst at 850℃ for 10 h.

[0090] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 55 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂S) of 0.5 h⁻¹. -1 The performance was evaluated under the conditions of reaction temperature 600℃ and water ratio 1.2 (wt), and the test results of the reaction are listed in Table 1.

[0091] Table 1. Catalyst composition, properties, and evaluation results for the examples and comparative examples.

[0092]

[0093]

[0094] 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. A catalyst for the dehydrogenation of ethylbenzene to styrene, comprising Fe, K, Ce, Mo, alkaline earth metals, carbon, and at least one element selected from Cl and Br; The catalyst, by weight, comprises the following components: (a) 60-85 parts of Fe2O3; (b) 8-18 parts of K2O; (c) 4-11 parts of CeO2; (d) 0.5 to 5 parts of MoO3; (e) 0.2 to 6 parts of alkaline earth metal oxides; (f) 0.1 to 1 part of Cl and / or Br; (g) 0.01 to 10 parts of carbon; The method for preparing the catalyst includes the following steps: A catalyst precursor is obtained by mixing Fe source, K source, Ce source, Mo source, alkaline earth metal source and optional pore-forming agent, and at least one source selected from Cl source and Br source, and then calcining the mixture after molding. The precursor is then subjected to chemical vapor deposition to introduce carbon elements to obtain the catalyst. The gas in the chemical vapor deposition process is one or more of alkanes, alkenes, and alkynes. The Cl source is selected from HCl and the Br source is selected from HBr.

2. The catalyst according to claim 1, characterized in that, The catalyst comprises 0.1 to 5 parts by weight of carbon.

3. The catalyst according to claim 1, characterized in that, The carbon mentioned is carbon deposits.

4. The catalyst according to claim 1, characterized in that, The catalyst includes Cl and Br.

5. The catalyst according to claim 4, characterized in that, The weight ratio of Cl to Br is 1:2 to 5:

1.

6. The catalyst according to claim 1, characterized in that, The weight ratio of component (f) Cl and / or Br and component (g) carbon is 0.05 to 30:

1.

7. A method for preparing the catalyst according to any one of claims 1 to 6, comprising the following steps: A catalyst precursor is obtained by mixing Fe source, K source, Ce source, Mo source, alkaline earth metal source and optional pore-forming agent, and at least one source selected from Cl source and Br source, followed by calcination after molding; the precursor is then subjected to chemical vapor deposition to introduce carbon element to obtain the catalyst; the gas in the chemical vapor deposition process is one or more of alkanes, alkenes, and alkynes, the Cl source is selected from HCl, and the Br source is selected from HBr.

8. The preparation method according to claim 7, characterized in that, In the chemical vapor deposition process, the gas includes at least one of ethane, ethylene, and acetylene.

9. The preparation method according to claim 7, characterized in that, The processing temperature in the chemical vapor deposition is 700~1000℃; and / or, the processing time is 1~48h; and / or, the gas mass hourly space velocity is 1~100h. -1 .

10. The preparation method according to claim 7, characterized in that, The Fe source is selected from Fe oxides; And / or, the K source is selected from potassium salts; And / or, the Ce source is selected from cerium salts; And / or, the Mo source is selected from molybdenum salts and / or molybdenum oxides; And / or, the alkaline earth metal source is selected from one or more alkaline earth oxides and alkaline earth metal hydroxides; And / or, the pore-forming agent is selected from one or more of activated carbon, graphite, sodium hydroxymethyl cellulose, and polystyrene microspheres.

11. The preparation method according to claim 10, characterized in that, The Fe source is selected from iron oxide red and / or iron oxide yellow; And / or, the K source is selected from one or more of potassium carbonate, potassium nitrate, and potassium bicarbonate; And / or, the Ce source is selected from one or more of cerium nitrate, cerium oxalate, and cerium carbonate; And / or, the Mo source is selected from one or more of ammonium molybdate and molybdenum oxide.

12. The use of a catalyst according to any one of claims 1 to 6 or a catalyst prepared by any one of claims 7 to 11 in the dehydrogenation of ethylbenzene to styrene reaction.

13. The application according to claim 12, characterized in that, The reaction temperature is 550~640℃; and / or, the reaction pressure is absolute pressure, 20~100kPa; and / or, the mass hourly space velocity of ethylbenzene is 0.2~2.0h. -1 .

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