Dehydrogenation catalyst, method for preparing and using the same, and method for preparing alkenylbenzene

Abstract

This invention relates to a dehydrogenation catalyst, specifically to a dehydrogenation catalyst, its preparation method and application, and a method for preparing alkenylbenzene. The dehydrogenation catalyst contains Fe, K, Ce, Mo, and alkaline earth metal elements, as well as at least one of P and S elements; wherein the catalyst phase contains KFe. 11 O 17 , and KFe 11 O 17 The average grain size is less than or equal to 60 nm. The catalyst described in this invention exhibits high yield and short induction period in the dehydrogenation reaction of alkylbenzenes (e.g., ethylbenzene) to alkenylbenzenes (e.g., styrene), achieving excellent technical results.

Description

Technical Field

[0001] This invention relates to a dehydrogenation catalyst, specifically to a dehydrogenation catalyst, its preparation method and application, and a method for preparing alkenylbenzene. Background Technology

[0002] Styrene is an important raw material for the synthetic rubber and plastics industries and plays a vital role in the national economy. The demand for styrene is extremely widespread, with direct downstream applications including EPS (expandable polystyrene), PS (polystyrene), and ABS (acrylonitrile-butadiene-styrene). End products include electronics, foam packaging, sheet materials, building materials, and household appliances, among many other fields.

[0003] The main methods for producing styrene are the ethylbenzene catalytic dehydrogenation method and the styrene-propylene oxide co-production method. The ethylbenzene catalytic dehydrogenation method uses ethylbenzene as a raw material, catalytically dehydrogenating it to styrene in the presence of steam, and accounts for approximately 85% of styrene production capacity. The co-production method uses propylene and ethylbenzene as raw materials to produce propylene oxide (PO) and styrene. While the process is more complex and requires greater investment, it has developed rapidly in recent years because it simultaneously yields two important basic organic raw materials, and its production capacity accounts for about 15% of the total styrene production capacity.

[0004] In the crucial petrochemical catalytic process of ethylbenzene dehydrogenation to styrene, the catalyst plays a key role, and its quality determines the economics of the dehydrogenation process. The research, development, and upgrading of ethylbenzene dehydrogenation catalysts have seen the rapid replacement of zinc- and magnesium-based catalysts used in the early stages of styrene industrialization by high-performance iron-potassium catalysts, which remain in use today. Most existing ethylbenzene dehydrogenation catalysts are Fe-K-Ce based, with Fe-K oxides as the main catalyst and Ce as the main promoter. They also contain structural stabilizers and electronic aids such as oxides of Mg, Mo, W, and Ca. CN106582678A discloses a Fe-K-Ce-W catalyst whose active phase is stabilized by introducing Ba, Sn, and rare earth oxides (Sm, Eu, Gd).

[0005] CN1981929A discloses a method for improving the stability and activity of a low-K catalyst under low water ratio conditions by adding at least two light rare earth oxide promoters (selected from at least two of La, Pr, Nd, and Sm) other than cerium to a Fe-K-Ce-W catalyst system, and simultaneously adding at least one metal oxide selected from Ca, Mg, Ba, B, Sn, Pb, Cu, Zn, Ti, Zr, or Mo.

[0006] Existing catalysts used in the ethylbenzene dehydrogenation reaction suffer from long activation periods and low activity to varying degrees. In industrial plants, it typically takes at least 6 to 7 days from the introduction of ethylbenzene to the catalyst activation and full-load operation; otherwise, the catalyst is prone to loss of activity, and it takes even longer to reach stable activity, leading to reduced production efficiency and increased energy consumption. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of long catalyst induction period and low activity in the existing ethylbenzene dehydrogenation technology, and to provide a dehydrogenation catalyst, its preparation method and application, as well as a method for preparing alkenylbenzene. This catalyst has the advantages of short induction period and high yield of target product in dehydrogenation reaction.

[0008] To achieve the above objectives, a first aspect of the present invention provides a dehydrogenation catalyst containing at least one of Fe, K, Ce, Mo, and alkaline earth metal elements, as well as P and S elements; wherein the catalyst phase contains KFe 11 O 17 , and KFe 11 O 17 The average grain size is less than or equal to 60 nm.

[0009] A second aspect of the present invention provides a method for preparing the dehydrogenation catalyst of the present invention, the method comprising:

[0010] The dehydrogenation catalyst is obtained by mixing Fe source, K source, Ce source, Mo source, alkaline earth metal source and optionally a pore-forming agent, as well as at least one of P source and S source, forming and then calcining. The content of P source is calculated as P2O5, the content of S source is calculated as SO3, and the amount of P source and S source is 0.1% to 2% of the total weight of catalyst raw materials.

[0011] A third aspect of the present invention provides the application of the dehydrogenation catalyst described herein in the dehydrogenation of alkylbenzene to prepare alkenylbenzene.

[0012] A fourth aspect of the present invention provides a method for preparing alkenylbenzene, the method comprising: contacting alkylbenzene, water and a catalyst, wherein the catalyst contains the dehydrogenation catalyst described in the present invention.

[0013] The dehydrogenation catalyst provided by the present invention, through the above technical solution, contains KFe in its phase. 11 O 17 , and KFe 11 O 17 The average grain size is less than or equal to 60 nm.

[0014] In this invention, the addition of P and / or S promoters during catalyst preparation can effectively limit the KFe content in the catalyst. 11 O17 The grain size; through research by the inventors, it was discovered that in the preparation process of the Fe-K-Ce system ethylbenzene dehydrogenation catalyst, in a preferred embodiment, calcination at a high temperature above 900℃ is used to reduce the KFe... 11 O 17 Rapid crystallization is beneficial for obtaining small crystallites and further regulating KFe 11 O 17 Grain size.

[0015] The inventors discovered through research that the induction period and reactivity of the Fe-K-Ce dehydrogenation catalyst are related to the potassium polyferrate (KFe) in the catalyst. 11 O 17 The grain size of KFe in the catalyst is directly related to the catalyst. 11 O 17 As a precursor to the catalytic active center, K ions gradually migrate under dehydrogenation reaction conditions, forming KFeO2, the active center for the dehydrogenation reaction, on the surface. Small-grained KFe... 11 O 17 It facilitates the rapid migration of K ions from the inner layer of the catalyst crystal to the surface, enabling the rapid formation of reactive sites in the dehydrogenation reaction and reducing the induction period; it also fully exposes the reactive sites, increases the density of active centers, and significantly improves the yield of the catalyst.

[0016] In this invention, the P and S additives not only regulate KFe 11 O 17 The effect of crystal size also improved the yield of alkenylbenzene while reducing the induction period.

[0017] The catalyst described in this invention exhibits high yield and short induction period in dehydrogenation reactions, such as the dehydrogenation of alkylbenzenes (e.g., ethylbenzene) to prepare alkenylbenzenes (e.g., styrene), achieving excellent technical results. Attached Figure Description

[0018] Figure 1 The XRD patterns of the catalyst prepared in Example 1 of this invention and the catalyst removed after the reaction are shown. Detailed Implementation

[0019] 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.

[0020] The first aspect of this invention provides a dehydrogenation catalyst containing at least one selected from Fe, K, Ce, Mo, and alkaline earth metals, as well as P and S; wherein the catalyst phase contains KFe. 11 O 17 , and KFe 11 O 17 The average grain size is less than or equal to 60 nm in the catalyst. 11 O 17 As a precursor to the catalytic active center, K ions gradually migrate under dehydrogenation reaction conditions, forming KFeO2, the active center for the dehydrogenation reaction, on the surface. Small-grained KFe... 11 O 17 It facilitates the rapid migration of K ions from the inner layer of the catalyst crystal to the surface, enabling the rapid formation of reactive sites in the dehydrogenation reaction and reducing the induction period; it also fully exposes the reactive sites, increases the density of active centers, and significantly improves the yield of the catalyst.

[0021] According to a preferred embodiment of the present invention, KFe 11 O 17 The average grain size is 10–50 nm, more preferably 10–40 nm.

[0022] According to a preferred embodiment of the present invention, the catalyst contains phosphorus (P) and sulfur (S), and preferably, the mass ratio of phosphorus to sulfur is 0.5 to 5:1.

[0023] The alkaline earth metals mentioned in this invention are selected from at least one of Ca, Mg, Ba and Sr. Preferably, the alkaline earth metals are selected from Ca and / or Mg, and more preferably Ca.

[0024] According to a preferred embodiment of the present invention, the catalyst comprises the following components based on the total mass of the catalyst and the elements calculated as oxides: (a) 60%–86% Fe₂O₃; (b) 8%–17% K₂O; (c) 4%–11% CeO₂; (d) 0.5%–5% MoO₃; (e) 0.2%–5% alkaline earth metal oxides; and (f) 0.1%–2% P and / or S; wherein the content of P is calculated as P₂O₅ and the content of S is calculated as SO₃.

[0025] All dehydrogenation catalysts having the aforementioned composition of this invention can achieve the objectives of this invention, and there are no special requirements for their preparation methods. In accordance with a preferred embodiment of this invention, this invention provides a method for preparing a dehydrogenation catalyst, comprising: mixing at least one of Fe source, K source, Ce source, Mo source, alkaline earth metal source, and optionally a pore-forming agent, as well as P source and S source; molding and then calcining to obtain the dehydrogenation catalyst; wherein the content of P source is calculated as P2O5, the content of S source is calculated as SO3, and the amount of P source and S source is 0.1% to 2% of the total weight of the catalyst raw materials.

[0026] In this invention, the calcination conditions can be conventional in the field, and calcination can be carried out at a temperature of 700°C or above. Preferably, the calcination temperature is 900-1100°C, and more preferably 920-1050°C.

[0027] The inventors discovered that, during the preparation of the Fe-K-Ce series ethylbenzene dehydrogenation catalyst, high-temperature calcination allows KFe to be converted into hydrogen peroxide. 11 O 17 Rapid crystallization is beneficial for obtaining small crystallites and further regulating KFe 11 O 17 Grain size. According to a preferred embodiment of the present invention, the calcination conditions include: a calcination temperature of 900–1100°C, preferably 920–1050°C; and a calcination time of 0.5–4 h, preferably 1–3 h. Using the aforementioned calcination conditions, rapid high-temperature calcination is achieved, resulting in KFe… 11 O 17 Rapid crystallization is beneficial for obtaining small crystal grains.

[0028] In this invention, the term "pore-forming agent" can optionally refer to adding a pore-forming agent or not adding a pore-forming agent; according to a preferred embodiment of the invention, the amount of the pore-forming agent is 0.01% to 5% of the total weight of the catalyst raw materials.

[0029] In this invention, the total weight of the catalyst raw materials refers to the sum of the mass of Fe source, K source, Ce source, Mo source and alkaline earth metal source as oxides, the mass of P source as P2O5, and the mass of S source as SO3.

[0030] In this invention, the molding process can be carried out according to actual needs. For example, extrusion molding can be used, and the strip shape can be a particle with a diameter of 2 to 5 mm and a length of 3 to 10 mm.

[0031] In this invention, an appropriate amount of water can be added during the kneading process. The water is added slowly, and the amount is not particularly limited and can be adjusted according to the dryness or wetness of the material. Generally, the amount of water added accounts for 15% to 35% of the total weight of the catalyst raw materials.

[0032] In this invention, the catalyst raw material can undergo a drying step after molding and before calcination.

[0033] According to a preferred embodiment of the present invention, the preparation method further includes: contacting the catalyst raw material with water, kneading it into shape, drying it, and calcining it to obtain the dehydrogenation catalyst.

[0034] According to a preferred embodiment of the present invention, the drying conditions include: a temperature of 30 to 200°C and a drying time of 1 to 24 hours.

[0035] According to a preferred embodiment of the present invention, the catalyst raw material contains both a P source and an S source. Preferably, the P source and the Fe source are first mixed to obtain mixture I, and then the S source, K source, Ce source, Mo source and alkaline earth metal source are added to mixture I to obtain mixture II. After molding and calcination, the dehydrogenation catalyst is obtained. This is beneficial to reduce the induction period and increase the yield.

[0036] This invention does not have any special requirements for the types of Fe source, K source, Ce source, Mo source, alkaline earth metal source, P source, S source, and pore-forming agent. Commonly used types can be used in this invention, and will not be described in detail here.

[0037] Exemplary examples include, but are not limited to, the Fe source being selected from Fe oxides, preferably from iron oxide red and / or iron oxide yellow; the K source being selected from potassium salts, preferably from one or more of potassium carbonate, potassium nitrate, and potassium bicarbonate; the Ce source being selected from cerium salts, preferably from one or more of cerium nitrate, cerium oxalate, and cerium carbonate; the Mo source being selected from molybdenum salts and / or molybdenum oxides, preferably from one or more of ammonium molybdate and molybdenum oxide; the alkaline earth metal source being selected from one or more of alkaline earth oxides and alkaline earth metal hydroxides; the P source being selected from one or more of phosphoric acid and phosphates; the S source being selected from one or more of sulfates; and the pore-forming agent being selected from one or more of activated carbon, graphite, sodium carboxymethyl cellulose, and polystyrene microspheres.

[0038] The catalyst preparation process described in this invention does not require the use of a binder, and the resulting catalyst may be binder-free.

[0039] A third aspect of the present invention provides the application of the dehydrogenation catalyst described herein in the dehydrogenation of alkylbenzene to prepare alkenylbenzene, preferably, the alkylbenzene is C8-C6. 10 One or more of alkylbenzenes, preferably ethylbenzene. The catalyst described in this invention exhibits a short induction period and high yield in the dehydrogenation reaction of alkylbenzenes (e.g., ethylbenzene) to alkenylbenzenes (e.g., styrene), achieving excellent technical results.

[0040] A fourth aspect of the present invention provides a method for preparing alkenylbenzene, the method comprising: contacting alkylbenzene, water and a catalyst, characterized in that the catalyst contains the dehydrogenation catalyst described in the present invention;

[0041] According to a preferred embodiment of the present invention, the contact conditions include a reaction temperature of 550–640°C.

[0042] According to a preferred embodiment of the present invention, the contact conditions include a pressure of 20 to 100 kPa, wherein the pressure is an absolute pressure.

[0043] According to a preferred embodiment of the present invention, the contact conditions include: a mass hourly space velocity (HHSV) of alkylbenzene of 0.2–2.0 h⁻¹. -1

[0044] According to a preferred embodiment of the present invention, water is preheated to become water vapor before entering the reactor and is fully mixed with alkylbenzene feed gas. Preferably, the weight ratio of water to alkylbenzene is 0.8 to 2.5.

[0045] Using the technical solution of this invention, for example, the dehydrogenation catalyst is evaluated for activity in an isothermal fixed bed at 60 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂O) of 1.0 h⁻¹. -1 The reaction was evaluated under the conditions of 600℃ (bed temperature and outlet temperature) and a water ratio (weight ratio of water to alkylbenzene) of 1.2. After 20 hours of reaction, the styrene yield reached over 76%. This indicates that the catalyst of this invention exhibits a short induction period and high styrene yield in the dehydrogenation of ethylbenzene to styrene, achieving good technical results.

[0046] In this invention, the induction period is the reaction time from the introduction of ethylbenzene to the activation of the catalyst until a stable styrene yield is achieved; a stable styrene yield means that the styrene yield reaches more than 99% of the average yield of the subsequent continuous reaction over 50 hours.

[0047] In this invention, XRD was performed using a Rigaku Ultima IV X-ray powder diffractometer from Japan, with a Cu-Kα ray source (λ = 0.15406 nm), a nickel filter, an operating voltage of 35 kV, a current of 25 mA, and a scanning rate of 2° / min.

[0048] In this invention, the KFe 11 O 17 The average grain size was calculated based on X-ray diffraction patterns and the Scherrer equation. The KFe... 11 O 17 The average grain size is based on the KFe X-ray diffraction pattern. 11 O 17(002) The diffraction peaks of the crystal plane, i.e., the diffraction peaks corresponding to the position 2θ=7.40±0.10°, are calculated using the Scherrer equation. The Scherrer equation, D=Kλ / βcosθ, describes the relationship between the average grain size and the half-maximum width (WHM) of the diffraction peaks in the XRD pattern. In the equation, D is the average size of the grain perpendicular to the crystal plane, K is the Scherrer constant, λ is the X-ray wavelength, β is the measured half-maximum width (WHM) of the diffraction peaks in the sample, and θ is the Bragg diffraction angle.

[0049] In this invention, the performance of the catalyst for the ethylbenzene dehydrogenation reaction is evaluated in an isothermal fixed bed. The process is briefly described below:

[0050] 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.

[0051] Ethylbenzene conversion and styrene selectivity are calculated using the following formulas:

[0052]

[0053] 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.

[0054] Example 1

[0055] Weigh out 48.3 parts of iron oxide red (Fe₂O₃), 22.9 parts of iron oxide yellow (Fe₂O₃), and 0.6 parts of phosphoric acid (P₂O₅) and stir in a mixer. Then weigh out 13.2 parts of potassium carbonate (K₂O), 9.7 parts of cerium nitrate (CeO₂), 3.2 parts of ammonium molybdate (MoO₃), 1.8 parts of calcium hydroxide (CaO), 0.3 parts of ammonium sulfate (SO₃), and 1.8 parts of sodium carboxymethyl cellulose and add them to the mixer and stir for 2 hours until homogeneous. Then add 24% of the total weight of the dehydrogenation catalyst raw materials and mix for 2 hours. Next, extrude and granulate the above mixture to obtain particles with a diameter of 3 mm and a length of 6 mm. Place them in an oven and dry at 80℃ for 4 hours, then at 160℃ for 4 hours. Finally, place them in a muffle furnace and calcine at 1000℃ for 1.5 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0056] The XRD pattern of the catalyst is shown below. Figure 1 As shown, this indicates the presence of potassium polyferrate (KFe) in the catalyst. 11 O 17 ), KFe 11 O 17The average grain size is 23.8 nm.

[0057] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 60 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂O) of 1.0 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.

[0058] Example 2

[0059] Weigh out 38.2 parts of iron oxide red (Fe₂O₃), 32.9 parts of iron oxide yellow (Fe₂O₃), and 0.3 parts of phosphoric acid (P₂O₅) and stir in a mixer. Then weigh out 12.9 parts of potassium carbonate (K₂O), 10.5 parts of cerium nitrate (CeO₂), 2.1 parts of ammonium molybdate (MoO₃), 2.5 parts of calcium hydroxide (CaO), 0.6 parts of ammonium sulfate (SO₃), and 0.9 parts of sodium carboxymethyl cellulose and add them to the mixer and stir for 2 hours until homogeneous. Then add 15% of the total weight of the dehydrogenation catalyst raw materials and mix for 2 hours. Next, extrude and granulate the above mixture to obtain particles with a diameter of 3 mm and a length of 6 mm. Place them in an oven and dry at 30°C for 12 hours, then at 200°C for 12 hours. Finally, place them in a muffle furnace and calcine at 920°C for 3 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0060] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 60 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂O) of 1.0 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 3

[0062] Weigh out 46.1 parts of iron oxide red (Fe₂O₃), 21.6 parts of iron oxide yellow (Fe₂O₃), and 1.0 part of phosphoric acid (P₂O₅) and stir in a mixer. Then weigh out 15.4 parts of potassium carbonate (K₂O), 10.2 parts of cerium nitrate (CeO₂), 3.8 parts of ammonium molybdate (MoO₃), 1.7 parts of calcium hydroxide (CaO), 0.2 parts of ammonium sulfate (SO₃), and 3.2 parts of sodium carboxymethyl cellulose and add them to the mixer and stir for 2 hours until homogeneous. Then add 35% of the total weight of the dehydrogenation catalyst raw materials and mix for 2 hours. Next, extrude and granulate the above mixture to obtain particles with a diameter of 3 mm and a length of 6 mm. Place them in an oven and dry at 80℃ for 4 hours, then at 160℃ for 4 hours. Finally, place them in a muffle furnace and calcine at 1050℃ for 1 hour to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0063] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 60 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂O) of 1.0 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 4

[0065] The method of Example 1 was followed, except that 0.9 parts of phosphoric acid and 0 parts of ammonium sulfate were added, while the other conditions were the same as in Example 1. The results are shown in Table 1.

[0066] Example 5

[0067] The method of Example 1 was followed, except that 0 parts of ammonium sulfate and 0.9 parts of phosphoric acid were added, while the other conditions were the same as in Example 1. The results are shown in Table 1.

[0068] Example 6

[0069] The method of Example 1 was followed, except that after drying, the sample was placed in a muffle furnace and calcined at 800°C for 6 hours to obtain the finished dehydrogenation catalyst. The other conditions were the same as in Example 1. The results are shown in Table 1.

[0070] Example 7

[0071] The method of Example 1 was followed, except that 1.8 parts of MgO were added to replace CaO, while the other conditions were the same as in Example 1. The results are shown in Table 1.

[0072] Example 8

[0073] Weigh out 63.8 parts of iron oxide red (Fe₂O₃) and 1.8 parts of phosphoric acid (P₂O₅) and stir in a mixer. Then weigh out 17.0 parts of potassium bicarbonate (K₂O), 11.0 parts of cerium carbonate (CeO₂), 5.0 parts of ammonium molybdate (MoO₃), 1.2 parts of calcium hydroxide (CaO), 0.2 parts of ammonium sulfate (SO₃), and 5.0 parts of polystyrene microspheres, and add them to the mixer and stir for 2 hours until homogeneous. Then add 24% of the total weight of the dehydrogenation catalyst raw materials and mix for 2 hours. Next, extrude and granulate the above mixture to obtain particles with a diameter of 3 mm and a length of 6 mm. Place them in an oven and dry at 80°C for 4 hours, then at 160°C for 4 hours. Finally, place them in a muffle furnace and calcine at 900°C for 4 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0074] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 60 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂O) of 1.0 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.

[0075] Example 9

[0076] The method is the same as in Example 1, except that 48.3 parts of iron oxide red (Fe₂O₃), 22.9 parts of iron oxide yellow (Fe₂O₃), 0.6 parts of phosphoric acid (P₂O₅), 13.2 parts of potassium carbonate (K₂O), 9.7 parts of cerium nitrate (CeO₂), 3.2 parts of ammonium molybdate (MoO₃), 1.8 parts of calcium hydroxide (CaO), 0.3 parts of ammonium sulfate (SO₃), and 1.8 parts of sodium carboxymethyl cellulose are added to a mixer and stirred for 2 hours until homogeneous. Then, 24% of the total weight of the dehydrogenation catalyst raw materials are added and mixed for 2 hours. The mixture is then extruded and granulated to obtain particles with a diameter of 3 mm and a length of 6 mm. These particles are dried in an oven at 80°C for 4 hours and then at 160°C for 4 hours. Finally, they are calcined in a muffle furnace at 1000°C for 1.5 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0077] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 60 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂O) of 1.0 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.

[0078] Example 10

[0079] Weigh out 78.7 parts of iron oxide red (Fe₂O₃) and 0.1 parts of phosphoric acid (P₂O₅) and stir in a mixer. Then weigh out 8.0 parts of potassium carbonate (K₂O), 9.6 parts of cerium nitrate (CeO₂), 0.5 parts of ammonium molybdate (MoO₃), 3.0 parts of CaO, 0.1 parts of ammonium sulfate (SO₃), and 1.8 parts of sodium hydroxymethyl 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 80°C for 4 hours, then at 160°C for 4 hours. Finally, calcine them in a muffle furnace at 1000°C for 1.5 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0080] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 60 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂O) of 1.0 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.

[0081] Comparative Example 1

[0082] Weigh out the following amounts: 49.2 parts of iron oxide red (Fe₂O₃), 22.9 parts of iron oxide yellow (Fe₂O₃), 13.2 parts of potassium carbonate (K₂O), 9.7 parts of cerium nitrate (CeO₂), 3.2 parts of ammonium molybdate (MoO₃), 1.8 parts of calcium hydroxide (CaO), and 1.8 parts of sodium carboxymethyl cellulose. 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 80°C for 4 hours, then at 160°C for 4 hours. Finally, calcine them in a muffle furnace at 800°C for 6 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0083] Catalyst evaluation: 100 mL of dehydrogenation catalyst was charged into the reactor at 60 kPa (absolute pressure) and ethylbenzene mass hourly space velocity (H₂O) of 1.0 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.

[0084] Comparative Example 2

[0085] The method was followed as in Example 1, except that 45.6 parts of iron oxide red (Fe₂O₃), 22.9 parts of iron oxide yellow (Fe₂O₃), and 3.6 parts of phosphoric acid (P₂O₅) were added, and ammonium sulfate was not added. All other conditions were the same as in Example 1. The results are shown in Table 1.

[0086] Comparative Example 3

[0087] The method was followed as in Example 1, except that 45.6 parts of iron oxide red (Fe₂O₃), 22.9 parts of iron oxide yellow (Fe₂O₃), and 3.6 parts of ammonium sulfate (SO₃) were added, and phosphoric acid was not added. All other conditions were the same as in Example 1. The results are shown in Table 1.

[0088] Table 1. Catalyst composition, properties, and evaluation results for the examples and comparative examples.

[0089]

[0090] Note: *The average grain size of CeO2 is calculated using the Scherrer equation.

[0091] **Add 1.8 parts MgO to replace CaO.

[0092] 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 dehydrogenation catalyst, characterized in that, The dehydrogenation catalyst contains Fe, K, Ce, Mo and alkaline earth metal elements, as well as at least one of P and S elements; The catalyst phase contains KFe. 11 O 17 , and KFe 11 O 17 The average grain size is less than or equal to 60 nm.

2. The dehydrogenation catalyst according to claim 1, wherein, KFe 11 O 17 The average grain size is 10–50 nm.

3. The dehydrogenation catalyst according to claim 1, wherein, KFe 11 O 17 The average grain size is 10–40 nm.

4. The dehydrogenation catalyst according to claim 1 or 2, wherein, The catalyst contains P and S elements; and / or The alkaline earth metal is selected from Ca and / or Mg.

5. The dehydrogenation catalyst according to claim 4, wherein, The mass ratio of phosphorus to sulfur is 0.5 to 5:1; and / or The alkaline earth metal is Ca.

6. The dehydrogenation catalyst according to claim 1 or 2, wherein, Based on the total mass of the catalyst, and considering elements as oxides, the catalyst comprises the following components: (a) 60%–86% Fe2O3; (b) 8%–17% K2O; (c) 4%–11% CeO2; (d) 0.5%–5% MoO3; (e) 0.2%–5% alkaline earth metal oxides; and (f) 0.1%–2% P and / or S.

7. A method for preparing the dehydrogenation catalyst according to any one of claims 1-6, characterized in that, The method includes: The dehydrogenation catalyst is obtained by mixing Fe source, K source, Ce source, Mo source, alkaline earth metal source and optionally a pore-forming agent, as well as at least one of P source and S source, and then calcining it after molding. The content of P source is calculated as P2O5, the content of S source is calculated as SO3, and the amount of P source and / or S source is 0.1% to 2% of the total weight of catalyst raw materials.

8. The preparation method according to claim 7, wherein, The roasting conditions include: a temperature of 900–1100℃; a time of 0.5–4 h; and / or The amount of the pore-forming agent is 0.01% to 5% of the total weight of the catalyst raw materials.

9. The preparation method according to claim 7, wherein, Calcination conditions include: temperature of 920–1050℃; time of 1–3 hours; and / or The preparation method further includes: contacting the catalyst raw material with water, kneading it into shape, drying it, and calcining it to obtain the dehydrogenation catalyst; the amount of water used is 15% to 35% of the total weight of the catalyst raw material; the drying conditions include: a temperature of 30 to 200°C and a drying time of 1 to 24 hours.

10. The preparation method according to claim 7 or 8, wherein, The catalyst feedstock contains both P and S sources.

11. The preparation method according to claim 10, wherein, First, P source and Fe source are mixed to obtain mixture I. Then, S source, K source, Ce source, Mo source and alkaline earth metal source are added to mixture I to obtain mixture II. After molding and calcination, the dehydrogenation catalyst is obtained.

12. The preparation method according to claim 7 or 8, wherein, 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 P source is selected from one or more of phosphoric acid and phosphates; and / or The S source is selected from one or more sulfates; and / or The pore-forming agent is selected from one or more of activated carbon, graphite, sodium hydroxymethyl cellulose, and polystyrene microspheres.

13. The preparation method according to claim 12, wherein, The Fe source is selected from iron oxide red and / or iron oxide yellow; 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.

14. The use of the dehydrogenation catalyst according to any one of claims 1-6 in the dehydrogenation of alkylbenzene to prepare alkenylbenzene.

15. The application according to claim 14, wherein, The alkylbenzene is C8-C. 10 One or more of the alkylbenzenes.

16. The application according to claim 14, wherein, The alkylbenzene is ethylbenzene.

17. A method for preparing alkenylbenzene, characterized in that, The method comprises contacting alkylbenzene, water and a catalyst, characterized in that the catalyst contains a dehydrogenation catalyst according to any one of claims 1-6.

18. The preparation method according to claim 17, wherein, Contact conditions include: a reaction temperature of 550–640°C; and / or The pressure is 20~100 kPa, wherein the pressure is absolute pressure; and / or The mass hourly space velocity (MSV) of alkylbenzenes is 0.2–2.0 h⁻¹. -1 ; and / or The weight ratio of water to alkylbenzene is 0.8 to 2.5.

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