Dehydrogenation catalyst, preparation method and application thereof, and method for preparing alkenyl arene

Abstract

The invention relates to a dehydrogenation catalyst, a preparation method and application thereof, and a method for preparing alkenyl arene. The catalyst comprises the following components in percentage by weight: (a) 65-86% of Fe2O3; (b) 6-12% of alkali metal oxide; (c) 7 to 13 percent of CeO2; (d) 0.5-4% of alkaline earth metal oxide; (e) 0.2 to 3 percent of a group VIB metal oxide; (f) 0.1 to 2 percent of VB group metal oxide; (g) 0.05 to 1 percent of heavy rare earth oxide; (h) 0.001 to 0.2% of an acidic oxide; (i) 0 to 4% of a binder. The catalyst provided by the invention has good catalytic activity under the condition of low water ratio in preparation of alkenyl arene or olefin, and the selectivity of alkenyl arene or olefin is high.

Description

Technical Field

[0001] The present invention relates to a dehydrogenation catalyst, a preparation method and application thereof, and a method for preparing vinyl aromatic hydrocarbons. Background Art

[0002] Vinyl aromatic hydrocarbons are important organic monomers in the chemical industry and can be used to synthesize plastics, rubbers, polyesters, etc. In industry, the typical production process is to produce them by dehydrogenation of alkyl aromatic hydrocarbons. Taking styrene as an example, ethylbenzene dehydrogenation is widely used industrially, accounting for more than 85% of the styrene production capacity. Ethylbenzene dehydrogenation is a strongly endothermic reversible reaction with an increase in the number of molecules. Superheated steam and ethylbenzene are fed at a certain water-oil ratio and contacted with a catalyst to react to produce styrene. The main by-products are low-value benzene and toluene. Industrially, Fe-K-Ce-based catalysts are mainly used for the direct catalytic dehydrogenation of ethylbenzene. Generally speaking, reducing the temperature, increasing the space velocity or introducing a small amount of CO into the raw material 2 is beneficial to the selectivity of styrene. Under the same reaction conditions, the selectivity of the catalyst is mainly affected by diffusion, surface acidity and basicity, surface composition and structure. The ethylbenzene dehydrogenation reaction is an internal diffusion-controlled reaction. Large pore diameters and low specific surface areas generally facilitate the diffusion of reactants and products and improve the selectivity of styrene. In addition, appropriate acidity and basicity, the electronic structure of active sites and coordination environment are also crucial for improving the selectivity of styrene.

[0003] Selectivity is an important index for evaluating industrial catalysts. Improving the selectivity of target products can reduce material consumption and separation energy consumption, improve the utilization rate of raw materials and increase economic benefits. In the prior art, to improve the selectivity of vinyl aromatic hydrocarbons of alkyl aromatic hydrocarbon dehydrogenation catalysts, the types and contents of structural assistants, the types of pore-forming agents or the preparation methods are mainly adjusted to control the pore structure of the catalyst or modify the Fe chemical environment.

[0004] Chinese Patent ZL03150717.4 reports that introducing ppm-level noble metals Rh and Pd into the Fe-K-Ce-Mo system can improve the styrene yield and reduce the toluene / benzene ratio.

[0005] Chinese Patent ZL201210240057.X reports the introduction of Ta 2 O 5 and group IVB metal oxides to modify the structure of the Fe-K-Ce-W-Mg catalyst system, which can reduce the toluene selectivity by 0.6% and increase the styrene selectivity by 0.5-1.0%.

[0006] CN202011099431.X discloses introducing a small amount of Ba, Li and group VB metal oxides into the Fe-K-Ce-W-Mg system, and at the same time controlling the number of basic sites of the catalyst within the range of 0.387-0.455 mmol / g, reducing the content of by-product benzene and significantly improving the styrene selectivity.

[0007] Although the above technologies have improved the styrene selectivity to a certain extent by using different additives or preparation methods, the applicable water ratio conditions are relatively mild. SUMMARY OF THE INVENTION

[0008] Based on the problems of poor selectivity and high by-products of low water ratio catalysts in the prior art, the object of the present invention is to provide a dehydrogenation catalyst resistant to low water ratio conditions and its preparation method. While maintaining good catalytic activity under low water ratio conditions, this catalyst has the characteristics of high selectivity.

[0009] To achieve the above object, on the one hand, the present invention provides a dehydrogenation catalyst, which comprises the following components by weight percentage: (a) 65-86% of Fe 2 O 3 ; (b) 6-12% of alkali metal oxide; (c) 7-13% of CeO 2 ; (d) 0.5-4% of alkaline earth metal oxide; (e) 0.2-3% of Group VIB metal oxide; (f) 0.1-2% of Group VB metal oxide; (g) 0.05-1% of heavy rare earth oxide; (h) 0.001-0.2% of acidic oxide; (i) 0-4% of binder.

[0010] On the second hand, the present invention provides a preparation method of the catalyst described above. The method includes: mixing an Fe source, an alkali metal source, a Ce source, an alkaline earth metal source, a Group VIB metal source, a Group VB metal source, a heavy rare earth metal source, a solvent and an optional binder source, shaping, and then optionally drying and calcining; then impregnating and contacting with an acidic oxide source, and optionally drying and calcining.

[0011] On the third hand, the present invention provides an application of the dehydrogenation catalyst in the preparation of vinyl aromatic hydrocarbons or olefins.

[0012] On the fourth hand, the present invention provides a method for preparing vinyl aromatic hydrocarbons. Using alkyl aromatic hydrocarbons as raw materials, the reaction temperature is 580-650 °C, the liquid hourly space velocity is 0.2-1.5 h -1 , the weight ratio of water to oil is 0.7-3.0, the pressure is 10 kPaA to atmospheric pressure, and the raw materials are mixed with steam and contacted with the catalyst to carry out dehydrogenation reaction.

[0013] The present invention adds at least one Group VB element oxide additive and a heavy rare earth oxide additive to the Fe-alkali metal-Ce-Group VIB-alkaline earth metal system, and preferably controls the mass ratio of the contained Group VIB and Group VB metal oxides to be 0.5-20, thereby improving the selectivity of the catalyst for vinyl aromatic hydrocarbons.

[0014] In addition, in the preferred embodiment, through the optimized design of the preparation method, the selectivity and yield of the catalyst for vinyl aromatic hydrocarbons are promoted. The catalyst prepared by the present invention is evaluated for performance in an isothermal fixed bed. Under the conditions of normal pressure, a reaction temperature of 620 °C, a liquid hourly space velocity of 1.0 h －1 , and a water ratio (by weight) of 1.05, the selectivity of vinyl aromatic hydrocarbons reaches 96.0% or even higher, achieving good technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the NH 3 -TPD spectrum of Example 1 of the catalyst of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0017] The present invention provides a dehydrogenation catalyst, which comprises the following components by weight percentage: (a) 65-86% of Fe 2 O 3 ; (b) 6-12% of alkali metal oxide; (c) 7-13% of CeO 2 ; (d) 0.5-4% of alkaline earth metal oxide; (e) 0.2-3% of Group VIB metal oxide; (f) 0.1-2% of Group VB metal oxide; (g) 0.05-1% of heavy rare earth oxide; (h) 0.001-0.2% of acidic oxide; (i) 0-4% of binder.

[0018] According to the preferred embodiment of the present invention, the ratio of the amount of strong acid sites to weak acid sites on the catalyst surface is (3.4-5.0):1, preferably (3.6-4.9):1, including but not limited to 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.5, 4.6, 4.7, 4.8, 4.9, etc. By adopting the aforementioned preferred embodiment, it is possible to modify and regulate the adsorption properties of products such as vinyl aromatic hydrocarbons in the process of dehydrogenating, for example, alkyl aromatic hydrocarbons to prepare vinyl aromatic hydrocarbons. On the basis of maintaining a certain activity, the generation of by-products in the dehydrogenation reaction is reduced, and the selectivity of vinyl aromatic hydrocarbons is improved.

[0019] According to a preferred embodiment of the present invention, the mass ratio of the Group VIB metal oxide to the Group VB metal oxide is 0.5 to 20, preferably 1.0 to 12. By adopting the foregoing preferred embodiment, the regulation of the acidity and basicity of the catalyst can be realized, and the selectivity of the vinyl aromatic hydrocarbon can be improved.

[0020] According to a preferred embodiment of the present invention, the catalyst does not contain cobalt oxide and nickel oxide.

[0021] In the present invention, alkali metal elements are all applicable to the present invention. According to a preferred embodiment of the present invention, the alkali metal elements include but are not limited to at least one of Na, K, and Rb. According to a preferred embodiment of the present invention, the alkali metal oxide is selected from at least one of Na 2 O, K 2 O, and Rb 2 O, and is preferably K 2 O; by adopting the foregoing preferred embodiment, it is possible to maintain a high catalytic activity under the reaction conditions.

[0022] In the present invention, alkaline earth metal elements are all applicable to the present invention. According to a preferred embodiment of the present invention, the alkaline earth metal elements include but are not limited to at least one of Mg, Ca, and Sr; according to a preferred embodiment of the present invention, the alkaline earth metal oxide is selected from at least one of MgO, CaO, and SrO; by adopting the foregoing preferred embodiment, it is possible to promote the formation of the ferrite precursor of the multi-alkali metal.

[0023] In the present invention, Group VIB elements are all applicable to the present invention. According to a preferred embodiment of the present invention, the Group VIB elements include but are not limited to at least one of Cr, Mo, and W; according to a preferred embodiment of the present invention, the Group VIB oxide contains Cr 2 O 3 、CrO 3 、MoO 2 、MoO 3 、WO 2 、WO 3 and at least one of them, and is preferably at least one of CrO 3 、MoO 3 、WO 3 ; by adopting the foregoing preferred embodiment, it is possible to realize appropriate crystal structure control and improvement of the reduction resistance performance.

[0024] In the present invention, preferably, the content of the Group VIB oxide is 0.25 to 2.8%, including but not limited to 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, 2.2%, 2.4%, 2.6%, etc.

[0025] In the present invention, elements of Group VB are all applicable to the present invention. According to a preferred embodiment of the present invention, the elements of Group VB include, but are not limited to, at least one of V, Nb, and Ta; according to a preferred embodiment of the present invention, the Group VB metal oxide contains V 2 O 3 、V 2 O 4 、V 2 O 5 、V 6 O 13 、NbO 2 、Nb 2 O 5 、Ta 2 O 5 and at least one of them, preferably at least one of V 6 O 13 、V 2 O 5 、Nb 2 O 5 、Ta 2 O 5 ; by adopting the foregoing preferred embodiment, the regulation of the electronic properties of the ferrate of alkali metal can be realized, and the generation of by-products can be reduced.

[0026] According to a preferred embodiment of the present invention, the content of the Group VB metal oxide is 0.1-2%, preferably 0.2-1.9%, including but not limited to 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, etc.

[0027] According to a preferred embodiment of the present invention, the heavy rare earth elements include, but are not limited to, at least one of Y, Dy, Ho, and Er, preferably at least two; according to a preferred embodiment of the present invention, the heavy rare earth oxide is preferably selected from at least two of Y 2 O 3 、Dy 2 O 3 、Ho 2 O 3 or Er 2 O 3 ; by adopting the foregoing preferred embodiment, the growth of CeO 2 crystals can be inhibited, and the stability of the catalyst under low water ratio conditions can be improved.

[0028] According to a preferred embodiment of the present invention, the acidic oxide contains one or more oxides of Al, Si, and P. According to a preferred embodiment of the present invention, the acidic oxide contains at least one of the oxides of Al, Si, and P; by adopting the foregoing preferred embodiment and combining with the preparation method of impregnation after molding preferably, the regulation of the ratio of weak acid sites and strong acid sites on the catalyst surface can be realized.

[0029] Catalysts having the aforementioned features of the present invention can all achieve the object of the present invention, and there are no special requirements for their preparation methods. For the present invention, a preparation method of a catalyst is provided. Among them, the method includes: mixing an Fe source, an alkali metal source, a Ce source, an alkaline earth metal source, a Group VIB metal source, a Group VB metal source, a heavy rare earth metal source, a solvent and an optional binder source, and after shaping, optionally drying and calcining; then impregnating and contacting with an acidic oxide source, and optionally drying and calcining.

[0030] According to a preferred embodiment of the present invention, the method includes the following steps:

[0031] (1) Mix an Fe source, an alkali metal source, a Ce source, an alkaline earth metal source, a Group VIB metal source, a Group VB metal source, a heavy rare earth metal source, a solvent, and an optional binder source evenly to form a first mixed powder containing a solvent;

[0032] (2) Add the first mixed powder to a solvent, knead and remove part of the solvent to form a second mixed paste;

[0033] (3) After extruding, pelletizing and drying the second mixed paste, impregnate it with an acidic oxide source.

[0034] In the present invention, there are no special requirements for the methods of mixing, kneading and removing the solvent. The following is a demonstration, but it does not limit the scope of the present invention.

[0035] In the present invention, step (1) can be mixed evenly, for example, in a continuous stirrer (belt type, plow type, etc.) or an intermittent high-speed mixer.

[0036] In the present invention, step (2) can be kneaded by adding a solvent in a kneader or a mill.

[0037] In the present invention, step (2) can remove part of the solvent by heating or negative pressure suction, for example.

[0038] In the present invention, for step (3), there are no special requirements for the steps and methods of extruding, pelletizing and drying the second mixed paste, and conventional techniques can be used. The present invention will not elaborate here.

[0039] In the present invention, it can be exemplarily described that it can be formed into cylindrical particles with a diameter of 3 mm and a length of 5-10 mm.

[0040] According to a preferred embodiment of the present invention, the method of the present invention includes:

[0041] (1) Mix the Fe source, alkali metal source, Ce source, alkaline earth metal source, Group VIB metal source, Group VB metal source, heavy rare earth metal source, solvent and an optional binder uniformly in a continuous stirrer or mixer to form a first mixed powder containing a certain amount of solvent;

[0042] (2) Transfer the first mixed powder to a kneader or attritor, add solvent and knead; remove part of the solvent by heating or negative pressure suction to form a second mixed paste.

[0043] (3) After extruding, pelletizing and drying the second mixed paste, impregnate it with a weak acid, weak base or salt containing an acidic metal to obtain a third mixed particle.

[0044] The present invention has no special requirements for various raw materials used, and the object of the present invention can be achieved as long as it is prepared according to the foregoing steps of the present invention.

[0045] In the present invention, common Fe sources can all achieve the object of the present invention. For the present invention, preferred Fe sources include but are not limited to one or more of iron nitrate, iron oxide red, iron oxide yellow, iron oxide blue, iron oxide green, iron oxide ash, and iron oxide black.

[0046] In the present invention, common alkali metal sources can all achieve the object of the present invention. For the present invention, alkali metal sources include but are not limited to at least one of oxides, hydroxides, carbonates and nitrates of alkali metals.

[0047] In the present invention, common Ce sources can all achieve the object of the present invention. For the present invention, Ce sources include but are not limited to at least one of cerium oxide, carbonate, basic carbonate, oxalate, nitrate, sulfate, hydroxide, and ammonium salt.

[0048] In the present invention, common alkaline earth metal sources can all achieve the object of the present invention. For the present invention, alkaline earth metal sources include but are not limited to at least one of oxides, hydroxides, carbonates, oxalates, and acetates of alkaline earth metals.

[0049] In the present invention, common Group VIB metal sources can all achieve the object of the present invention. For the present invention, Group VIB metal sources include but are not limited to at least one of oxides, nitrates, metalates, and ammonium metalates of Group VIB metals.

[0050] In the present invention, common Group VB metal sources can all achieve the object of the present invention. For the present invention, Group VB metal sources include but are not limited to at least one of oxides, hydroxides, ortho salts, meta salts, and ammonium salts of Group VB metals.

[0051] In the present invention, common heavy rare earth metal sources can all achieve the purpose of the present invention. For the present invention, the heavy rare earth metal sources include, but are not limited to, at least one of oxides, nitrates, acetates, oxalates, and carbonates of heavy rare earths.

[0052] In the present invention, in addition to the main components of the catalyst, a binder can be optionally added. Common binder sources can all achieve the purpose of the present invention. For the present invention, the binder sources include, but are not limited to, at least one of kaolin, diatomite, cement, silica sol, pseudoboehmite, potassium silicate, montmorillonite, halloysite, meta-halloysite, saponite, rectorite, sepiolite, attapulgite, hydrotalcite, bentonite, polyacrylamide, sodium polyacrylate, starch, cellulose ether, and povidone.

[0053] In the present invention, the types of solvents can be selected from a relatively wide range. For the present invention, the solvents are selected from one or more of water, alcohols, esters, ketones, ethers, and hydrocarbons; preferably selected from one or more of water, methanol, ethanol, acetone, ethylene glycol, glycerol, and pyrrolidone, and preferably include at least two of water, methanol, ethanol, acetone, ethylene glycol, glycerol, and pyrrolidone. This can further improve the activity of the catalyst.

[0054] In the present invention, the types of acidic oxide sources can be selected from a relatively wide range. Generally, Al 2 O 3 、SiO 2 、P 2 O 5 at least one of them. For the present invention, the preferred acidic oxide sources include one or more of weak acids, weak bases, and salts of acidic metals.

[0055] In the present invention, there is no special requirement for the total amount of the solvent. Common solvent dosages can all achieve the purpose of the present invention. For the present invention, the total amount of the preferred solvent is 15-40% of the total mass of the catalyst calculated as oxides, including but not limited to 18%, 21%, 24%, 27%, 30%, 33%, 36%, 39%, etc.

[0056] In the present invention, the optional range of the operating conditions in step (1) is relatively wide. The following is a demonstration, but it does not limit the scope of the present invention. In the present invention, the purpose of forming the first powder is to uniformly mix the raw material powder and the binder. For the present invention, the solvent content of the first mixed powder is 1-10% by weight of the total mass of the catalyst calculated as oxides, including but not limited to 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, etc.

[0057] In the present invention, the optional range of the solvent in step (1) is relatively wide, and common types of solvents can all be used in the present invention. For the present invention, preferably, the solvent described in step (1) includes one or more of water, alcohols, esters, ketones, ethers, and hydrocarbons; preferably, it includes one or more of water, C1-C3 alcohols, and C1-C3 ketones; more preferably, it includes at least one of water, methanol, ethanol, and acetone, and still more preferably, it is water and ethanol. Preferably, the mass ratio of water to ethanol is 1-10:1, and more preferably, it is 2-3:1.

[0058] In the present invention, the optional range of the operating conditions in step (2) is relatively wide. The following is a demonstration but does not limit the scope of the present invention thereby. For the present invention, preferably, the content of the solvent used in the second mixing is 5-39% by weight of the total mass of the catalyst calculated as the oxide, including but not limited to 9%, 13%, 17%, 21%, 25%, 29%, 33%, 37%, etc.

[0059] In the present invention, the optional range of the solvent in step (2) is relatively wide, and common types of solvents can all be used in the present invention. For the present invention, preferably, the solvent described in step (2) includes one or more of water, alcohols, esters, ketones, ethers, hydrocarbons, and amides; preferably, it includes one or more of C2-C3 diols and / or triols; preferably, it includes at least one of water, ethylene glycol, glycerol, and pyrrolidone, and still more preferably, it is water and glycerol. Preferably, the mass ratio of water to glycerol is 0.1-10:1, and more preferably, it is the same amount of water and glycerol.

[0060] In the present invention, the purpose of forming the second mixed paste is to make the raw material powder into a non-Newtonian fluid with viscoelasticity and thixotropy, which is convenient for the subsequent catalyst forming. For the present invention, the solid content of the second mixed paste is 65-100% by weight, preferably 80-95% by weight, including but not limited to 82%, 84%, 86%, 88%, 90%, 92%, 94%, etc.

[0061] Adopting the aforementioned preferred implementation manners can achieve the uniform distribution of each component raw material in the catalyst and ensure the impregnation effect of the acidic oxide.

[0062] In the present invention, in step (3), there is no special requirement for the impregnation method. For the present invention, preferably, in step (3), the impregnation adopts the equal-volume impregnation or the excess impregnation method.

[0063] In the present invention, there is no special requirement for the conditions of drying and calcination. For the present invention, specifically, by way of example, for example, the drying temperature is 50-200°C, the drying time is 4-48 hours, the calcination temperature is 300-1300°C, and the calcination time is 3-18 hours.

[0064] According to a preferred embodiment of the present invention, the drying is carried out in two steps. The temperature of the first drying is 50 - 80 °C; the temperature of the second drying is 100 - 130 °C. The optional range of the time for the first drying and the second drying is relatively wide. For example, the time for the first drying is 10 - 15 h, and the time for the second drying is 20 - 28 h.

[0065] According to a preferred embodiment of the present invention, the calcination is carried out in two steps. The temperature of the first calcination is 300 - 500 °C; the temperature of the second calcination is 800 - 1000 °C. The optional range of the time for the first calcination and the second calcination is relatively wide. For example, the time for the first calcination is 1 - 6 h, and the time for the second calcination is 2 - 8 h.

[0066] According to a preferred embodiment of the present invention, the drying is carried out in two steps. The temperature of the first drying is 50 - 80 °C and the time is 10 - 15 h; the temperature of the second drying is 100 - 130 °C and the time is 20 - 28 h. Thereby, the performance of the catalyst can be improved.

[0067] According to a preferred embodiment of the present invention, the calcination is carried out in two steps. The temperature of the first calcination is 300 - 500 °C and the time is 1 - 6 h; the temperature of the second calcination is 800 - 1000 °C and the time is 2 - 8 h. Thereby, the performance of the catalyst can be improved.

[0068] The dehydrogenation catalyst of the present invention has the advantages of high product selectivity and few by-products, and can be applied to various dehydrogenation reactions. The application of the dehydrogenation catalyst described in the present invention in the preparation of vinyl aromatic hydrocarbons or olefins is provided.

[0069] According to a preferred embodiment of the present invention, a method for preparing vinyl aromatic hydrocarbons is provided. Using alkyl aromatic hydrocarbons as raw materials, the reaction temperature is 580 - 650 °C, the liquid hourly space velocity is 0.2 - 1.5 h -1 , the weight ratio of water to oil is 0.7 - 3.0, the pressure is 10 kPaA - atmospheric pressure, and the raw materials are mixed with steam and contacted with the catalyst to carry out dehydrogenation reaction.

[0070] The catalyst of the present invention overcomes the problems of poor selectivity and many by-products of the low water ratio catalyst in the prior art, and has the characteristics of high selectivity of the target product while maintaining good catalytic activity under the condition of low water ratio.

[0071] The performance evaluation of the catalyst prepared by the method of the present invention in an isothermal fixed bed for ethylbenzene dehydrogenation reaction is briefly described as follows:

[0072] The reactor is a stainless steel tube with an inner diameter of 1", filled with 50-150 ml of cylindrical catalyst with a diameter of 3 mm and a length of 5-10 mm. Deionized water and ethylbenzene are respectively fed into the preheating mixer through metering pumps, and then preheated and mixed into gaseous state before entering the reactor. The reactor is heated by electric heating wire to reach the predetermined temperature. The reaction temperature is 580-650°C, and the liquid space velocity is 0.2-1.5 hours －1 , water ratio (water / ethylbenzene weight ratio) is 0.7 to 3.0 (preferably less than 1.2, 1.05 in the embodiment), and pressure is 10 KPaA to normal pressure. The reactants flowing out of the reactor are condensed with water and analyzed for their composition by gas chromatography.

[0073] The ethylbenzene conversion rate and styrene selectivity are calculated according to the following formula:

[0074]

[0075]

[0076]

[0077]

[0078] The solid content of the paste of the present invention is measured by a thermogravimetric analyzer. The specific steps are as follows: 10-20 mg of powder or block sample is taken and heated to 400 °C at N 2 The temperature was raised to 600°C at a heating rate of 5°C / min under a solvent atmosphere, and the thermal weight loss rate of the paste within the boiling point range of the corresponding solvent as the temperature rises was accurately weighed, and the solid content was calculated.

[0079] The acidic sites of the catalyst of the present invention are NH 3 -Programmed temperature desorption (NH 3 -TPD) method analysis, TCD detector detection, take 0.1-0.2g catalyst sample particles with a particle size of 40-60 mesh, pre-treat at 550℃ for 1 hour in He atmosphere, then cool to below 60℃, adsorb 10% NH 3 / He to equilibrium, switch to He gas, wait for the baseline at 100℃, blow flat, raise the temperature to 650℃ at 10℃ / min, record NH 3 Desorption spectrum. The ratio of strong acid / weak acid sites was calculated based on the area ratio of the high-temperature desorption peak (strong acid site) >400℃ and the low-temperature desorption peak (weak acid site) <400℃.

[0080] In the present invention, the catalyst composition is the composition calculated based on the input materials.

[0081] Example 1

[0082] Red iron oxide, potassium hydroxide, cerium carbonate, ammonium molybdate, WO 3, magnesium oxalate, CaO, ammonium metavanadate, niobium hydroxide, Y 2 O 3 , erbium nitrate, methylcellulose, and solvent ethanol equivalent to 5% of the catalyst's mass in terms of oxide are stirred in a mixer for 2 hours until evenly mixed. Mix at 100 rpm in a continuous mixer, and transfer the obtained first mixed powder to a kneader;

[0083] Solvent water equivalent to 20% of the catalyst's mass in terms of oxide is uniformly dropped into the mixer of the kneader, and wet kneaded at a negative pressure of 50 kPaA for 20 min. Sampling and analysis by a thermogravimetric analyzer show that the solid content of the obtained paste is 84.3%. After taking out the obtained paste, it is extruded and pelletized to obtain particles with a diameter of 3 mm and a length of 5 - 10 mm. Subsequently, a silicic acid solution equivalent to 0.01 part of SiO 2 is impregnated on the particles in an equal volume, and left standing for 4 h. Then it is put into an oven, dried at 70 °C for 12 hours, dried at 120 °C for 24 hours, and finally placed in a muffle furnace, calcined at 450 °C for 4 hours and at 900 °C for 4 hours to obtain the finished catalyst, and the catalyst composition is listed in Table 1.

[0084] Figure 1 is the NH 3 -TPD spectrum of Catalyst Example 1. The ratio of the number of strong acid sites to weak acid sites of the catalyst measured by NH 3 -TPD is 4.30.

[0085] Load 100 mL of the catalyst into a reactor, and conduct performance evaluation under the conditions of normal pressure, a liquid hourly space velocity of 1.0 h －1 , a temperature of 620 °C, and a water ratio of 1.05 (wt). The test results are listed in Table 2.

[0086] Example 2

[0087] Iron oxide yellow, potassium carbonate, cerium basic carbonate, sodium nitrate, MoO 3 , chromium nitrate, magnesium hydroxide, SrO, V 6 O 13 , dysprosium nitrate, Ho 2 O 3 , methylcellulose, and solvent methanol equivalent to 2% of the catalyst's mass in terms of oxide are stirred in a mixer for 0.5 hour until evenly mixed. Mix at 80 rpm in a continuous mixer, and transfer the obtained first mixed powder to a attritor;

[0088] Solvent water equivalent to 14% of the catalyst's mass in terms of oxide is uniformly dropped into the attritor, and wet kneaded at a negative pressure of 20 kPaA for 120 min. Sampling and analysis by a thermogravimetric analyzer show that the solid content of the obtained paste is 94.6%. After taking out the obtained paste, it is extruded and pelletized to obtain particles with a diameter of 3 mm and a length of 5 - 10 mm. Subsequently, an amount equivalent to 0.11 part of Al2 O 3 Equal volumes of aluminic acid and 0.07 parts of phosphoric acid solution were impregnated on the particles and left standing for 4 h. Then, they were placed in an oven, dried at 60 °C for 12 h, dried at 100 °C for 24 h, and finally placed in a rotary kiln, calcined at 350 °C for 4 h and calcined at 850 °C for 4 h to obtain the finished catalyst. The catalyst composition is listed in Table 1. By NH 3 -TPD, the ratio of the number of strong acid sites to weak acid sites of the catalyst was measured to be 4.75.

[0089] The catalyst was tested and evaluated according to the method of Example 1, and the test results are listed in Table 2.

[0090] Example 3

[0091] Iron oxide red, potassium nitrate, cerium nitrate, ammonium tungstate, magnesium carbonate, Nb 2 O 5 , yttrium nitrate, dysprosium nitrate, Ho 2 O 3 , Er 2 O 3 , methyl cellulose, and solvent water equivalent to 10% of the mass of the catalyst in terms of oxides were stirred in a mixer for 1 h until evenly mixed. They were mixed at 70 rpm in a continuous mixer, and the first mixed powder was transferred to a kneader;

[0092] A mixed solvent of water + ethylene glycol (1:1) equivalent to 30% of the mass of the catalyst in terms of oxides was uniformly dropped into the kneader, and wet kneading was carried out at a negative pressure of 80 kPaA for 10 min. Sampling and analysis by a thermogravimetric analyzer showed that the solid content of the obtained paste was 80.50%. After taking out the obtained paste, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 - 10 mm. Subsequently, equal volumes of aluminic acid solution equivalent to 0.002 parts of Al 2 O 3 were impregnated on the particles and left standing for 4 h. Then, they were placed in an oven, dried at 50 °C for 12 h, dried at 110 °C for 24 h, and finally placed in a muffle furnace, calcined at 400 °C for 4 h and calcined at 820 °C for 4 h to obtain the finished catalyst. The catalyst composition is listed in Table 1. By NH 3 -TPD, the ratio of the number of strong acid sites to weak acid sites of the catalyst was measured to be 3.65.

[0093] The catalyst was tested and evaluated according to the method of Example 1, and the test results are listed in Table 2.

[0094] Example 4

[0095] Compared with Example 1, "5% of solvent ethanol" was replaced with "5% of water + ethanol (mass ratio of water to ethanol is 2:1)", and "20% of solvent water" was replaced with "20% of water + glycerol (mass ratio of water to glycerol is 1:1)", and other steps were the same as in Example 1. The catalyst composition is listed in Table 1.

[0096] Through NH 3 -TPD measurement shows that the ratio of the number of strong acid sites to weak acid sites of the catalyst is 4.16.

[0097] The catalyst was tested and evaluated according to the method of Example 1, and the test results are listed in Table 2.

[0098] Example 5

[0099] Compared with Example 1, the proportion of some raw materials was changed. Other steps were the same as those in Example 1, and the catalyst composition is listed in Table 1.

[0100] Through NH 3 -TPD measurement shows that the ratio of the number of strong acid sites to weak acid sites of the catalyst is 4.83.

[0101] The catalyst was tested and evaluated according to the method of Example 1, and the test results are listed in Table 2.

[0102] Example 6

[0103] Compared with Example 1, the difference is that nickel oxide was added. Other steps were the same as those in Example 1, and the catalyst composition is listed in Table 1.

[0104] Through NH 3 -TPD measurement shows that the ratio of the number of strong acid sites to weak acid sites of the catalyst is 4.05.

[0105] The catalyst was tested and evaluated according to the method of Example 1, and the test results are listed in Table 2.

[0106] Example 7

[0107] Compared with Example 1, while keeping the mass ratio between oxides of the same group elements constant, the mass ratio of elements in Groups VIB and VB and the content of acidic oxides were adjusted. Other steps were the same as those in Example 1, and the catalyst composition is listed in Table 1.

[0108] Through NH 3 -TPD measurement shows that the ratio of the number of strong acid sites to weak acid sites of the catalyst is 3.47.

[0109] The catalyst was tested and evaluated according to the method of Example 1, and the test results are listed in Table 2.

[0110] Example 8

[0111] Compared with Example 3, the raw materials and conditions were changed, and yellow iron oxide, potassium hydroxide, cerium nitrate, ammonium metatungstate, calcium hydroxide, V 6 O 13 、niobium oxalate, Ho 2 O 3 、erbium nitrate, methyl cellulose, and solvent water equivalent to 10% of the catalyst mass were mixed evenly in a mixer.

[0112] A mixed solvent of water + ethylene glycol (1:1) equivalent to 30% of the catalyst mass was uniformly dropped into a kneader and wet kneaded at atmospheric pressure for 30 min. Other steps were the same as in Example 3, and the catalyst composition is listed in Table 1.

[0113] Analysis by a thermogravimetric analyzer showed that the solid content of the second mixed paste was 69.7%. By NH 3 -TPD, the number ratio of strong acid sites to weak acid sites of the catalyst was measured to be 3.91.

[0114] The catalyst was tested and evaluated according to the method of Example 1, and the test results are listed in Table 2.

[0115] Comparative Example 1

[0116] Compared with Example 1, it did not contain a Group VB metal oxide promoter, and other steps were the same as in Example 1. The catalyst composition is listed in Table 1.

[0117] By NH 3 -TPD, the number ratio of strong acid sites to weak acid sites of the catalyst was measured to be 7.58.

[0118] The catalyst was tested and evaluated according to the method of Example 1, and the test results are listed in Table 2.

[0119] Comparative Example 2

[0120] Compared with Example 2, there was no acidic oxide impregnation treatment, and other steps were the same as in Example 2. The catalyst composition is listed in Table 1.

[0121] By NH 3 -TPD, the number ratio of strong acid sites to weak acid sites of the catalyst was measured to be 15.1.

[0122] The catalyst was tested and evaluated according to the method of Example 1, and the test results are listed in Table 2.

[0123] Table 1

[0124]

[0125]

[0126] Table 2

[0127]

[0128] Note: The evaluation conditions for the above examples were selected as a space velocity of 1.0 h -1 , and a water ratio (wt) of 1.05.

[0129] The above examples and comparative examples illustrate that adding a certain proportion of at least one oxide promoter of Group VB metals (V, Nb, Ta) and heavy rare earth metal (Y, Dy, Ho, Er) oxide promoters in the iron-alkali metal-cerium-VIB group-alkaline earth metal system, and preferably in the preferred embodiment, introducing a trace amount of acidic oxide on the catalyst surface and controlling the mass ratio of the Group VIB and Group VB metal oxides contained in the catalyst, the catalyst has a high selectivity for vinyl aromatic hydrocarbons under low water ratio conditions and is suitable for the industrial production of dehydrogenating alkyl aromatic hydrocarbons to vinyl aromatic hydrocarbons under low water ratio conditions.

[0130] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the technical concept scope of the present invention, various simple modifications can be made to the technical solutions of the present invention, including combining each technical feature in any other suitable manner. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A dehydrogenation catalyst, characterized in that, The catalyst comprises the following components by weight percentage: (a) 65-86% of Fe 2 O 3 ; (b) 6-12% of alkali metal oxide; (c) 7-13% of CeO 2 ; (d) 0.5-4% of alkaline earth metal oxide; (e) 0.2-3% of Group VIB metal oxide; (f) 0.1-2% of Group VB metal oxide; (g) 0.05-1% of heavy rare earth oxide; (h) 0.001-0.2% of acidic oxide; (i) 0-4% of binder.

2. The catalyst according to claim 1, wherein, the ratio of the amount of strong acid sites to weak acid sites on the catalyst surface is (3.4 - 5.0):1, preferably (3.6 - 4.9):1; and / or the mass ratio of the metal oxide of Group VIB to the metal oxide of Group VB is 0.5 to 20, preferably 1.0 to 12; and / or the catalyst does not contain cobalt oxide and nickel oxide.

3. The catalyst according to claim 1 or 2, wherein, the alkali metal element includes at least one of Na, K, and Rb; and / or the alkaline earth metal element includes at least one of Mg, Ca, and Sr; and / or the element of Group VIB includes at least one of Cr, Mo, and W; and / or the element of Group VB includes at least one of V, Nb, and Ta; and / or the heavy rare earth element includes at least one of Y, Dy, Ho, and Er; preferably includes at least two of Y, Dy, Ho, and Er; and / or the acidic oxide includes one or more oxides of Al, Si, and P.

4. A method for preparing the catalyst according to any one of claims 1 - 3, wherein, the method includes: mixing an Fe source, an alkali metal source, a Ce source, an alkaline earth metal source, a Group VIB metal source, a Group VB metal source, a heavy rare earth metal source, a solvent, and an optional binder source, followed by optional drying and calcination after shaping; then impregnating and contacting with an acidic oxide source, and optionally drying and calcining.

5. According to the preparation method of claim 4, the mixing includes the following steps: (1) Mix the Fe source, the alkali metal source, the Ce source, the alkaline earth metal source, the Group VIB metal source, the Group VB metal source, the heavy rare earth metal source, the solvent, and the optional binder source evenly to form a first mixed powder containing the solvent; (2) Add the first mixed powder to the solvent, knead, and remove part of the solvent to form a second mixed paste; (3) Extrude, granulate, and dry the second mixed paste, and then impregnate it with the acidic oxide source.

6. According to the preparation method of claim 4 or 5, wherein, the Fe source includes one or more of iron nitrate, iron oxide red, iron oxide yellow, iron oxide blue, iron oxide green, iron oxide gray, and iron oxide black; and / or the alkali metal source includes at least one of the oxide, hydroxide, carbonate, and nitrate of the alkali metal; and / or the Ce source includes at least one of cerium oxide, carbonate, basic carbonate, oxalate, nitrate, sulfate, hydroxide, and ammonium salt; and / or the alkaline earth metal source includes at least one of the oxide, hydroxide, carbonate, oxalate, and acetate of the alkaline earth metal; and / or the Group VIB metal source includes at least one of the oxide, nitrate, metalate, and ammonium metalate of the Group VIB metal; and / or the Group VB metal source includes at least one of the oxide, hydroxide, ortho - salt, meta - salt, and ammonium salt of the Group VB metal; and / or the heavy rare earth metal source includes at least one of the oxide, nitrate, acetate, oxalate, and carbonate of the heavy rare earth; and / or The binder source includes at least one of kaolin, diatomaceous earth, cement, silica sol, pseudo-boehmite, potassium silicate, montmorillonite, halloysite, meta-halloysite, saponite, rectorite, sepiolite, attapulgite, hydrotalcite, bentonite, polyacrylamide, sodium polyacrylate, starch, methyl cellulose, cellulose ether, and povidone; and / or The solvent is selected from one or more of water, alcohols, esters, ketones, ethers, and hydrocarbons; preferably selected from one or more of water, methanol, ethanol, acetone, ethylene glycol, glycerol, and pyrrolidone, and preferably includes at least two of water, methanol, ethanol, acetone, ethylene glycol, glycerol, and pyrrolidone; and / or The acidic oxide source includes one or more of weak acids, weak bases, and salts of acidic metals; and / or The total amount of the solvent is 15-40% of the total mass of the catalyst calculated as oxides.

7. The preparation method according to any one of claims 5-6, wherein, in step (1), the solvent content of the first mixed powder is 1-10% by weight of the total mass of the catalyst calculated as oxides; the solvent includes one or more of water, alcohols, esters, ketones, ethers, and hydrocarbons; preferably includes at least one of water, methanol, ethanol, and acetone; more preferably water and ethanol; and / or in step (2), the solvent content used for the second mixing is 5-39% by weight of the total mass of the catalyst calculated as oxides; and / or the solvent includes one or more of water, alcohols, esters, ketones, ethers, hydrocarbons, and amides; preferably includes at least one of water, ethylene glycol, glycerol, and pyrrolidone; more preferably water and glycerol; and / or the solid content of the second mixed paste is 65-100% by weight, preferably 80-95% by weight; and / or in step (3), the impregnation is carried out by the equal-volume impregnation or the excess impregnation method.

8. The preparation method according to any one of claims 4-7, wherein, the drying temperature is 50-200 °C, and the calcination temperature is 300-1300 °C; preferably, the drying is carried out in two steps. The temperature of the first drying is 50-80 °C; the temperature of the second drying is 100-130 °C; and / or the calcination is carried out in two steps. The temperature of the first calcination is 300-500 °C; the temperature of the second calcination is 800-1000 °C; more preferably, preferably, the drying is carried out in two steps. The temperature of the first drying is 50-80 °C, and the time is 10-15 h; the temperature of the second drying is 100-130 °C, and the time is 20-28 h; and / or the calcination is carried out in two steps. The temperature of the first calcination is 300-500 °C, and the time is 1-6 h; the temperature of the second calcination is 800-1000 °C, and the time is 2-8 h.

9. The application of the dehydrogenation catalyst in the preparation of vinyl aromatic hydrocarbons or olefins.

10. A method for preparing vinyl aromatic hydrocarbons, using alkyl aromatic hydrocarbons as raw materials, with a reaction temperature of 580 - 650 °C, a liquid hourly space velocity of 0.2 - 1.5 h -1 , a water / oil weight ratio of 0.7 - 3.0, a pressure of 10 kPaA - atmospheric pressure, and the raw materials are mixed with steam and contacted with a catalyst to undergo a dehydrogenation reaction.

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