Dehydrogenation catalyst, preparation method and application thereof, and alkyl aromatic hydrocarbon dehydrogenation method

Abstract

The invention relates to the technical field of catalysts, in particular to a dehydrogenation catalyst, a preparation method and application thereof and an alkyl aromatic hydrocarbon dehydrogenation method. The dehydrogenation catalyst comprises the following components in percentage by mass: (a) 62 to 80 percent of Fe2O3; (b) 8-14% of at least one of alkali metal oxides; (c) 6 to 15 percent of CeO2; (d) 0.1 to 5% of WO3; (e) 0.2-6% of at least one of alkaline earth metal oxides; (f) 0.01%-3% of at least one of VIIB group metal oxides; (g) 0.01-2% of at least one of rare earth metal oxides; the pore size of the dehydrogenation catalyst is in bimodal distribution of the most probable pore sizes of 300 + / -200nm and 1100 + / -300nm. The multistage macroporous structure of the dehydrogenation catalyst reduces the bulk density of the catalyst, reduces the mass transfer resistance, improves the diffusion efficiency of the catalyst, reduces side reactions, and improves the selectivity of the catalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a dehydrogenation catalyst, a preparation method and an application thereof, and an alkylaromatic hydrocarbon dehydrogenation method. Background Art

[0002] Styrene monomer is an important organic chemical raw material. 85% of styrene in industry is produced by catalytic dehydrogenation of ethylbenzene. The main reaction is C6H5-C2H5→C6H5CH=CH2+H2ΔH f 298 =+123kJ / mol. This reaction is an endothermic reaction with an increase in volume. Increasing the temperature and decreasing the pressure are beneficial to the formation of styrene. Introducing a large amount of steam plays roles such as providing heat, promoting chemical equilibrium, inducing the formation of the active phase of the catalyst, suppressing carbon deposition, and maintaining the oxidation state of the catalyst system. The activation of the catalyst precursor to generate a metastable potassium ferrate phase, the high-temperature cracking of water, and the vaporization of carbon determine that this reaction is usually carried out at a high temperature above 600°C. Most of the existing styrene catalysts are mainly based on Fe-K, with iron oxide as the main catalyst and K as the main promoter, and also contain promoters such as oxides of Ce, Mg, Mo, W or Ca. In recent years, the demand pressure from aspects such as energy conservation, consumption reduction, cost reduction and efficiency increase in the market has promoted the requirements for catalysts to develop towards more resistance to low water ratio, higher selectivity, and low bulk density.

[0003] In terms of olefin selectivity, in the prior art, the selectivity of the catalyst is mainly improved by regulating the proportion and type of promoters. Its essence is to adjust the electronic state of the active phase potassium ferrate or the structure of the Fe active center. In terms of the bulk density of the catalyst, in the prior art, the bulk density is mainly adjusted by optimizing the composition and type of the binder or pore former. For example, CN101455968A discloses a Fe-K-Ce-Mo-Mg-Ca-La ethylbenzene dehydrogenation to styrene catalyst and a preparation method thereof, introducing a small amount of Pb, B, Mn promoters. Under the isothermal bed conditions of 620°C, a water ratio of 2.0 (weight), and a space velocity of 1.0h -1 The selectivity can reach 96.6%, but its water ratio is relatively high. Chinese Patent ZL202011098582.3 reports a Fe-K-Ce-W-Ba ethylbenzene dehydrogenation to styrene catalyst and a preparation method thereof, introducing a small amount of metal oxides of Group IA other than K, regulating the weak base amount of the catalyst to be 0.425-0.455mmol / g, at -60kPa, and a mass space velocity of 0.7h -1, at 625 °C and a water ratio of 0.6 (by weight), the selectivity can reach 96.7%, but the bulk density of the catalyst is not mentioned. US10494317 reports a Fe-K-Ce dehydrogenation catalyst containing promoters such as Mo, Ca, Na, rare earth elements other than Ce, and noble metals. By adjusting the promoter composition and the catalyst preparation method, at 91 kPa, a water ratio of 1.0 (by weight), and a mass space velocity of 1.0 h -1 , at 540 - 620 °C, the styrene selectivity can reach 98% at a 50% conversion rate. However, the high selectivity of this catalyst is achieved by reducing the reaction conversion rate, and the bulk density of the catalyst is also not mentioned. SUMMARY OF THE INVENTION

[0004] Based on the problems in the prior art of high catalyst bulk density and low olefin selectivity under low water ratio conditions, a dehydrogenation catalyst, its preparation method and application, and an alkylarene dehydrogenation method are provided. The dehydrogenation catalyst has a bimodal distribution of the most probable pore diameters and a low bulk density. The dehydrogenation catalyst is used for alkylarene dehydrogenation and maintains good olefin selectivity under low water ratio conditions.

[0005] To achieve the above object, in the first aspect of the present invention, a dehydrogenation catalyst is provided. Calculated on a mass percentage basis, the dehydrogenation catalyst comprises:

[0006] (a) 62 - 80% of Fe2O3; (b) at least one of 8 - 14% of alkali metal oxides; (c) 6 - 15% of CeO2; (d) 0.1 - 5% of WO3; (e) at least one of 0.2 - 6% of alkaline earth metal oxides; (f) at least one of 0.01 - 3% of Group VIIB metal oxides; (g) at least one of 0.01 - 2% of rare earth metal oxides;

[0007] The dehydrogenation catalyst has a bimodal distribution of the most probable pore diameters of 300 ± 200 nm and 1100 ± 300 nm.

[0008] In the second aspect of the present invention, a preparation method of the dehydrogenation catalyst of the present invention is provided. The method comprises:

[0009] By one of wet granulation, dry granulation, tabletting, template method, foaming method, and gel method, an Fe source, an alkali metal source, a Ce source, a W source, an alkaline earth metal source, a Group VIIB metal source, a rare earth metal source, a pore former, and optionally a solvent are mixed and granulated, dried, and the pore former is removed;

[0010] wherein, the pore former comprises a first pore former and a second pore former;

[0011] The first pore former is selected from at least one of synthetic polymer microsphere materials;

[0012] The second pore-forming agent is selected from at least one of inorganic carbon materials, natural polymer materials and their products, naphthalene powder, paraffin wax, inorganic fillers, and ethyl silicate.

[0013] The third aspect of the present invention provides an application of the dehydrogenation catalyst described in the present invention in the dehydrogenation of alkyl aromatics.

[0014] The fourth aspect of the present invention provides a method for dehydrogenating alkyl aromatics, which includes:

[0015] Under the conditions of alkyl aromatic dehydrogenation, contacting an alkyl aromatic, water, and a catalyst; the catalyst includes the dehydrogenation catalyst described in the present invention.

[0016] Through the above technical solution, the dehydrogenation catalyst described in the present invention has a bimodal pore size distribution characteristic. The hierarchical macroporous structure of the dehydrogenation catalyst reduces the bulk density of the catalyst, reduces the mass transfer resistance, improves the diffusion efficiency of the catalyst, reduces side reactions, and improves the selectivity of the catalyst. The dehydrogenation catalyst described in the present invention has a high selectivity for vinyl aromatics and a low bulk density in the dehydrogenation reaction of alkyl aromatics (such as ethylbenzene) to vinyl aromatics (such as styrene) under low water ratio conditions, achieving good technical effects. Description of the Drawings

[0017] Figure 1 is the pore size distribution diagram of the catalyst prepared in Example 1. Detailed Embodiments

[0018] 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, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values 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.

[0019] In the present invention, the pore structure (pore size, etc.) of the catalyst is measured by a Pascal140 / 240 type low / high pressure mercury porosimeter of Thermo Electron Corporation (contact angle of 130°, mercury surface tension of 0.473 N / m); the test range of the 140 type low pressure mercury porosimeter: pressure: 0.1 - 400 kPa, pore size: 3.8 - 116 um; the test range of the 240 type high pressure mercury porosimeter: pressure: 200 MPa, pore size: 0.0074 - 15 um.

[0020] The first aspect of the present invention provides a dehydrogenation catalyst, which includes, in terms of mass percentage:

[0021] (a) 62 - 80% Fe2O3; (b) at least one of 8 - 14% alkali metal oxides; (c) 6 - 15% CeO2; (d) 0.1 - 5% WO3; (e) at least one of 0.2 - 6% alkaline earth metal oxides; (f) at least one of 0.01 - 3% group VIIB metal oxides; (g) at least one of 0.01 - 2% rare earth metal oxides;

[0022] The pore size of the dehydrogenation catalyst exhibits a bimodal distribution of the most probable pore sizes of 300 ± 200 nm and 1100 ± 300 nm.

[0023] The dehydrogenation catalyst described in the present invention has a bimodal pore size distribution characteristic. The hierarchical macroporous structure of the dehydrogenation catalyst reduces the bulk density of the catalyst, reduces the mass transfer resistance, improves the diffusion efficiency of the catalyst, reduces side reactions, and improves the selectivity of the catalyst.

[0024] According to a preferred embodiment of the present invention, the pore size of the dehydrogenation catalyst exhibits a bimodal distribution of the most probable pore sizes of 300 ± 100 nm and 1100 ± 200 nm.

[0025] The hierarchical macroporous structure of the dehydrogenation catalyst described in the present invention reduces the bulk density of the catalyst; according to a preferred embodiment of the present invention, the bulk density of the dehydrogenation catalyst is 1.0 - 1.3 kg / L.

[0026] According to a preferred embodiment of the present invention, the dehydrogenation catalyst comprises: (a) 64 - 78% Fe2O3.

[0027] According to a preferred embodiment of the present invention, the dehydrogenation catalyst comprises: (b) at least one of 10 - 13% alkali metal oxides.

[0028] According to a preferred embodiment of the present invention, the dehydrogenation catalyst comprises: (c) 7 - 14% CeO2.

[0029] According to a preferred embodiment of the present invention, the dehydrogenation catalyst comprises: (d) 0.3 - 3% WO3.

[0030] According to a preferred embodiment of the present invention, the dehydrogenation catalyst comprises: (e) at least one of 0.5 - 5% alkaline earth metal oxides.

[0031] According to a preferred embodiment of the present invention, the dehydrogenation catalyst comprises: (f) at least one selected from group VIIB metal oxides in an amount of 0.1 - 2%.

[0032] According to a preferred embodiment of the present invention, the dehydrogenation catalyst comprises: (g) at least one selected from rare earth metal oxides in an amount of 0.05 - 1%.

[0033] In the dehydrogenation catalyst, the weight ratio of the Group VIIB metal oxide to the rare earth metal oxide is 0.05 - 5.0.

[0034] According to a preferred embodiment of the present invention, the alkali metal oxide is selected from at least one of Li2O, Na2O, and K2O; preferably a combination of K2O with Li2O or Na2O, and preferably the mass ratio of Li2O or Na2O to K2O is 0.1 - 0.2.

[0035] According to a preferred embodiment of the present invention, the alkaline earth metal oxide is at least one of MgO, CaO, and SrO.

[0036] According to a preferred embodiment of the present invention, the Group VIIB metal oxide is selected from at least one of MnO2, ReO2, and Re2O7.

[0037] According to a preferred embodiment of the present invention, the rare earth oxide is selected from at least one of La2O3 and Gd2O3.

[0038] In a second aspect of the present invention, there is provided a method for preparing the dehydrogenation catalyst of the present invention, the method comprising: mixing an Fe source, an alkali metal source, a Ce source, a W source, an alkaline earth metal source, a Group VIIB metal source, a rare earth metal source, a pore-forming agent, and optionally a solvent by one of wet granulation, dry granulation, tabletting, templating, foaming, and gelation methods, granulating, drying, and removing the pore-forming agent;

[0039] wherein the pore-forming agent includes a first pore-forming agent and a second pore-forming agent;

[0040] The first pore-forming agent is selected from at least one of synthetic polymer microsphere materials;

[0041] The second pore-forming agent is selected from at least one of inorganic carbon materials, natural polymer materials and their products, naphthalene powder, paraffin wax, inorganic fillers, and ethyl silicate.

[0042] The present invention adds at least one Group VIIB metal (such as Mn, Re) oxide promoter and at least one rare earth metal oxide (such as La, Gd) promoter to the iron-alkali metal-cerium-tungsten-alkaline earth metal system. In addition, at least 2 kinds of pore-forming agents are used to prepare a dehydrogenation catalyst with a bimodal pore size distribution characteristic.

[0043] According to a preferred embodiment of the present invention, the inorganic carbon material is selected from at least one of carbon powder, carbon spheres, carbon nanotubes, carbon fibers, activated carbon, carbon black, foam carbon, and graphite.

[0044] According to a preferred embodiment of the present invention, the natural polymer material and its products are selected from at least one of starch, protein, cellulose, cellulose ether, alginate, gelatin, chitosan, agarose, and dextran.

[0045] The present invention does not particularly limit the type of starch, for example, it includes but is not limited to potato flour, wheat flour, rice flour, etc.

[0046] The present invention does not particularly limit the type of protein, for example, it includes but is not limited to albumin, etc.

[0047] In the present invention, in the synthetic polymer microsphere material, the synthetic polymer refers to a synthetic high molecular polymer or a synthetic high molecular polymer salt; according to a preferred embodiment of the present invention, in the synthetic polymer microsphere material, the synthetic polymer is selected from at least one of cellulose ether, polyvinylpyrrolidone, polyacrylamide, sodium polyacrylate, polystyrene microspheres, polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), styrene - divinylbenzene copolymer (PS - DVB), polyethylene glycol (PEG), polyacrylic acid (PAA), polyethylene oxide (PEO), polypropylene carbonate (PPC), polylactic acid (PLA), polyurethane (PU), polypropylene carbonate (PPC), polyvinylpyrrolidone (PVP), polyethylene - vinyl acetate (PEVA), polydimethylsiloxane (PDMS), polyurea formaldehyde (PUF), polyacrylonitrile, polysiloxane, and polylactic acid - glycolic acid copolymer.

[0048] According to a preferred embodiment of the present invention, the inorganic filler is selected from at least one of kaolin, diatomite, cement, montmorillonite, halloysite, meta - halloysite, saponite, rectorite, sepiolite, attapulgite, hydrotalcite, bentonite, potassium silicate, silicon borate, pseudo - boehmite, silica spheres, silicon carbide, ammonium carbonate, ammonium bicarbonate, and urea.

[0049] In the present invention, during the wet granulation mixing process, a solvent is added to mix the components (such as kneading), and there is no particular requirement for the addition method of the solvent. For example, it can be added drop by drop.

[0050] In the present invention, the addition amount of the solvent is adjusted according to the mixing time and the dry - wet degree of the materials. Preferably, the addition amount of the solvent is 10 - 50% by weight, preferably 15 - 30% by weight, based on the total addition amount of the Fe source, alkali metal source, Ce source, W source, alkaline earth metal source, Group VIIB element source, and rare earth metal source calculated as oxides.

[0051] In the present invention, there is no particular limitation on the type of the solvent. The solvent is selected from at least one of water, alcohols, esters, ketones, ethers, or hydrocarbons, and preferably a mixed solvent of water and alcohols;

[0052] According to a preferred embodiment of the present invention, the alcohol is selected from C1-C4 alcohols, for example, it can be one or more of methanol, ethanol, ethylene glycol, glycerol, 1-propanol.

[0053] According to a preferred embodiment of the present invention, the ketone is selected from one or more of C3-C4 ketones.

[0054] According to a preferred embodiment of the present invention, the ester solvent is selected from one or more of methyl formate, ethyl formate, propyl formate, isopropyl formate, butyl formate, benzyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate, benzyl acetate, ethyl propionate, propyl propionate, butyl propionate, amyl propionate, ethyl oxalate, butyl oxalate, amyl oxalate, ethyl carbonate, ethyl benzoate.

[0055] According to a preferred embodiment of the present invention, the ether solvent is selected from one or more of diethyl ether, dipropyl ether, diisopropyl ether, ethyl butyl ether, dibutyl ether, dipentyl ether, diisopentyl ether, dihexyl ether, dibenzyl ether.

[0056] According to a preferred embodiment of the present invention, the hydrocarbon solvent is selected from one or more of pentane, benzene, toluene, xylene, hexane, heptane.

[0057] In the present invention, the method for removing the pore former is selected according to the type of the pore former, and the method for removing the pore former is selected from one or more of alkali etching, roasting, and solvent dissolution.

[0058] When ammonium carbonate, ammonium bicarbonate, or urea in inorganic carbon materials, natural polymer materials and their products, synthetic polymer microsphere materials, and inorganic fillers is used as the pore former, it can be removed by roasting or solvent dissolution.

[0059] When the inorganic filler is used as the pore former, alkali etching or solvent dissolution can be selected according to actual needs for removal.

[0060] In the present invention, there is no particular limitation on the solution concentration used for the alkali etching, as long as it can remove the pore former.

[0061] In the present invention, the range of the drying conditions is relatively wide. According to a preferred embodiment of the present invention, the drying conditions include: the temperature is 30-200 °C, and the time is 6-24 h; preferably, it is dried at 50-100 °C for 4-16 h, and then the temperature is raised to 120-180 °C and dried for 2-8 h.

[0062] In the present invention, the range of the amount of the pore former used is relatively wide. According to a preferred embodiment of the present invention, based on the total mass of the metal oxides of each metal source, the amount of the pore former is 0.1%-8% of the metal source, preferably 0.5-6%.

[0063] According to a preferred embodiment of the present invention, the mass ratio of the first pore-forming agent to the second pore-forming agent is 1:20 - 2:1.

[0064] According to a preferred embodiment of the present invention, the particle size range of the synthetic polymer microsphere material is 200 nm - 5 μm, preferably 500 nm - 2 μm.

[0065] In the present invention, the range of the calcination conditions is relatively wide. According to a preferred embodiment of the present invention, the calcination conditions include: the temperature is 200 - 1000 °C, and the time is 2 - 12 hours; preferably, it is calcined at 300 - 500 °C for 1 - 6 hours, and then heated to 600 - 900 °C and calcined for 1 - 6 hours.

[0066] In the present invention, there is no particular limitation on the calcination method. For example, the heating method for calcination can be selected as resistance wire heating or microwave heating.

[0067] According to a preferred embodiment of the present invention, the preparation method of the dehydrogenation catalyst includes:

[0068] (1) Mix an Fe source, an alkali metal source, an alkaline earth metal source, a first pore-forming agent, and a solvent to obtain a first mixed wet powder;

[0069] (2) Mix a Ce source, a W source, a Group VIIB metal source, a rare earth metal source, a second pore-forming agent, and a solvent to obtain a second mixed colloid or suspension;

[0070] (3) Blend the first mixed wet powder with the second mixed colloid or suspension, knead into shape, dry, and calcine; the first pore-forming agent is selected from at least one of polystyrene microspheres, polystyrene - divinylbenzene copolymers, polyvinylpyrrolidone, polymethyl methacrylate, polyvinyl alcohol, polyethylene glycol, poly(lactic - glycolic acid) copolymer (polylactide - co - glycolide);

[0071] The second pore-forming agent is selected from at least one of starch, cellulose, cellulose ether, carbon powder, and graphite.

[0072] In the above preparation method, there is no particular limitation on the order of steps (1) and (2), which is only used to distinguish the preparation of the two mixtures.

[0073] In the present invention, the range of each metal source is relatively wide, and it can be oxides, salts, complexes, etc. of each metal.

[0074] According to a preferred embodiment of the present invention, the Fe source is selected from at least one of iron oxide red, iron oxide yellow, iron oxide green, iron oxide black, iron nitrate, and iron sulfate; preferably iron oxide red and iron oxide yellow.

[0075] According to a preferred embodiment of the present invention, the alkali metal source is selected from at least one of oxides, carbonates, bicarbonates, and hydroxides.

[0076] According to a preferred embodiment of the present invention, the Ce source used is selected from at least one of cerium oxide, cerium oxalate, cerium acetate, cerium carbonate, cerium nitrate, cerium hydroxide, and basic cerium carbonate.

[0077] According to a preferred embodiment of the present invention, the W source used is selected from at least one of tungstates, metatungstates, and tungsten trioxide.

[0078] According to a preferred embodiment of the present invention, the alkaline earth metal source is selected from at least one of oxides, hydroxides, or carbonates.

[0079] According to a preferred embodiment of the present invention, the Group VIIB metal source used is selected from at least one of Group VIIB (Mn, Re) metal oxides, hydroxides, nitrates, acetates, oxalates, carbonates, sulfates, stearates, and perrhenates.

[0080] According to a preferred embodiment of the present invention, the rare earth metal source is selected from at least one of rare earth metal oxides, hydroxides, nitrates, carbonates, and oxalates, preferably rare earth metal nitrates and carbonates.

[0081] In the present invention, there is no particular limitation on the shape of the catalyst, and the specific shape can be determined according to actual needs.

[0082] The third aspect of the present invention provides an application of the dehydrogenation catalyst described in the present invention in the dehydrogenation of alkyl aromatics.

[0083] The fourth aspect of the present invention provides a method for dehydrogenating alkyl aromatics, which includes:

[0084] Under the conditions of alkyl aromatic dehydrogenation, contacting the alkyl aromatic, water, and the catalyst; the catalyst includes the dehydrogenation catalyst described in the present invention.

[0085] In the reaction of dehydrogenating alkyl aromatics (such as ethylbenzene) to produce vinyl aromatics (such as styrene) under low water ratio conditions using the dehydrogenation catalyst described in the present invention, it has a high selectivity for vinyl aromatics and a low bulk density, achieving good technical effects.

[0086] According to a preferred embodiment of the present invention, the weight ratio of water to alkyl aromatic is 0.9 - 1.3.

[0087] According to a preferred embodiment of the present invention, the volume space velocity of the alkyl aromatic is 0.1 - 2 h -1 。

[0088] According to a preferred embodiment of the present invention, the dehydrogenation reaction conditions include: a temperature of 580 - 650 °C and a pressure of 20 kPaA - atmospheric pressure; where kPaA refers to absolute pressure.

[0089] According to a preferred embodiment of the present invention, the alkylarene is ethylbenzene.

[0090] To further understand the present invention, the preferred embodiments of the present invention will be described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0091] To illustrate the present invention more clearly, the following examples are listed, but the applicable cases of the present invention are not limited to the scope of the examples.

[0092] Referring to the petrochemical industry standard NB / SH / T 0958 - 2017 "Determination Method for Mechanical Tapped Bulk Density of Shaped Catalysts and Catalyst Supports", the catalyst bulk density test method is as follows:

[0093] Take a dry and clean measuring cylinder, weigh its mass m1 accurately to 0.1 g. Take a certain amount of dried sample, slowly pour it into the measuring cylinder through a funnel, while pouring the sample, rotate the funnel until the sample water level reaches about 250 ml. The pouring process should be controlled within 20 - 30 s, and the pouring speed should be as uniform as possible. Quickly weigh the total mass m2 of the sample and the measuring cylinder accurately to 0.1 g. Firmly install the measuring cylinder on the measuring cylinder base of the vibration equipment, and set the number of vibrations to 1000 times. After the vibration ends, read the volume (V) of the sample in the measuring cylinder accurately to 1 ml.

[0094] The tapped bulk density of the sample is denoted as D, and the value is expressed in grams per milliliter (g / ml). It is calculated according to the following formula:

[0095]

[0096] Take the arithmetic mean of the results of two repeated determinations as the final analysis result, and round the analysis result according to the provisions of GB / T 8170. The result is expressed to two decimal places.

[0097] In the following examples, the performance evaluation of the catalyst for ethylbenzene dehydrogenation reaction was carried out in an isothermal fixed bed, and the process is briefly described as follows:

[0098] The reactor is a stainless steel tube with an inner diameter of 1", filled with 100 ml of cylindrical catalyst with a diameter of 3 mm. Deionized water and ethylbenzene are respectively input into the preheating mixer through metering pumps, preheated and mixed into a gaseous state and then enter the reactor. The reactor is heated by an electric heating wire to reach the predetermined temperature.

[0099] At 80 kPaA, liquid hourly space velocity 1.0 h-1 Under the conditions of a temperature of 620 °C and a water ratio of 1.0 (wt), the performance of the catalyst was evaluated. The reactants flowing out of the reactor were condensed with water and then analyzed for their composition using a gas chromatograph.

[0100] The conversion of ethylbenzene and the selectivity of styrene under steady state were calculated according to the following formulas:

[0101]

[0102]

[0103] Example 1

[0104] By weight, weighed iron oxide red equivalent to 73.45 parts of Fe2O3, cerium carbonate equivalent to 9.76 parts of CeO2, potassium hydroxide equivalent to 10.8 parts of K2O, sodium nitrate equivalent to 1.62 parts of Na2O, ammonium tungstate equivalent to 1.37 parts of WO3, calcium hydroxide equivalent to 2.03 parts of CaO, 0.47 parts of MgO, 0.31 parts of MnO2, lanthanum nitrate equivalent to 0.19 parts of La2O3, 0.98 parts of polystyrene - divinylbenzene microspheres (1.5 μm), and 3.02 parts of starch were stirred in a mixer for 1 hour until evenly mixed;

[0105] 15.1 parts of deionized water were added to the obtained mixture, kneaded for 1 hour, taken out, extruded into strips and cut into granules to obtain granules with a diameter of 3 mm and a length of 5 - 10 mm. They were placed in an oven, dried at 50 °C for 10 hours, dried at 160 °C for 5 hours, and then placed in a muffle furnace, calcined at 400 °C for 3 hours and calcined at 750 °C for 3 hours to obtain the finished catalyst.

[0106] The pore size distribution diagram of the dehydrogenation catalyst is as Figure 1 shown. It can be seen that the catalyst exhibits a bimodal distribution of the most probable pore size.

[0107] The results of the evaluation of the most probable pore size, bulk density, and ethylbenzene dehydrogenation reaction performance of the dehydrogenation catalyst are shown in Table 1.

[0108] Example 2

[0109] By weight, weighed iron oxide red equivalent to 78 parts of Fe2O3, cerium carbonate equivalent to 7 parts of CeO2, potassium hydroxide equivalent to 9 parts of K2O, sodium nitrate equivalent to 1 part of Na2O, ammonium tungstate equivalent to 0.3 parts of WO3, calcium hydroxide equivalent to 4.54 parts of CaO, 0.1 parts of MnO2, lanthanum nitrate equivalent to 0.06 parts of La2O3, and 3 parts of polymethyl methacrylate (average particle size 2 μm), and 3 parts of methyl cellulose were stirred in a mixer for 1 hour until evenly mixed;

[0110] Add 16 parts of deionized water to the obtained mixture, knead for 1 hour, take out and extrude, cut into pellets to obtain pellets with a diameter of 3 mm and a length of 5-10 mm, put into an oven, bake at 50°C for 10 hours, bake at 160°C for 5 hours, then place in a muffle furnace, bake at 500°C for 2 hours, and bake at 650°C for 6 hours to obtain the finished catalyst.

[0111] The most probable pore size, bulk density and ethylbenzene dehydrogenation reaction performance evaluation results of the dehydrogenation catalyst are shown in Table 1.

[0112] Example 3

[0113] According to weight, 64 parts of red iron oxide equivalent to Fe2O3, 14 parts of cerium carbonate equivalent to CeO2, 11 parts of potassium hydroxide equivalent to K2O, 2 parts of sodium nitrate equivalent to Li2O, 3 parts of ammonium tungstate equivalent to WO3, 3.1 parts of MgO, 2 parts of ReO2, 0.9 parts of gadolinium nitrate equivalent to Gd2O3, 0.5 parts of poly(lactide-glycolide) PGLA microspheres (1 μm), and 2 parts of graphite were weighed and stirred in a mixer for 1 hour until the mixture was uniformly mixed;

[0114] Add 15 g of deionized water to the resulting mixture, knead for 1 hour, take it out, extrude it into strips, and cut it into pellets to obtain particles with a diameter of 3 mm and a length of 5-10 mm. Put it into an oven, bake it at 50°C for 10 hours, bake it at 160°C for 5 hours, then place it in a muffle furnace, bake it at 300°C for 6 hours, and bake it at 850°C for 1 hour to obtain the finished catalyst.

[0115] The most probable pore size, bulk density and ethylbenzene dehydrogenation reaction performance evaluation results of the dehydrogenation catalyst are shown in Table 1.

[0116] Example 4

[0117] According to weight, 73.45 parts of red iron oxide equivalent to Fe2O3, 9.76 parts of cerium carbonate equivalent to CeO2, 12.42 parts of potassium hydroxide equivalent to K2O, 1.37 parts of ammonium tungstate equivalent to WO3, 2.03 parts of calcium hydroxide equivalent to CaO, 0.47 parts of MgO, 0.31 parts of MnO2, 0.19 parts of lanthanum nitrate equivalent to La2O3, 0.98 parts of polystyrene-divinylbenzene microspheres (1.5 μm), and 3.02 parts of starch were weighed and stirred in a mixer for 1 hour until the mixture was uniform;

[0118] Add 15.1 parts of deionized water to the obtained mixture, knead for 1 hour, take out and extrude into strips, cut into pellets to obtain pellets with a diameter of 3 mm and a length of 5-10 mm, put into an oven, bake at 50°C for 10 hours, bake at 160°C for 5 hours, then place in a muffle furnace, roast at 400°C for 3 hours, and roast at 750°C for 3 hours to obtain the finished catalyst.

[0119] The results of the evaluation of the most probable pore diameter, bulk density, and ethylbenzene dehydrogenation reaction performance of the dehydrogenation catalyst are shown in Table 1.

[0120] Example 5

[0121] Weigh iron oxide red equivalent to 73.45 parts of Fe2O3, cerium carbonate equivalent to 9.76 parts of CeO2, potassium hydroxide equivalent to 10.8 parts of K2O, sodium nitrate equivalent to 1.62 parts of Na2O, ammonium tungstate equivalent to 1.37 parts of WO3, calcium hydroxide equivalent to 2.03 parts of CaO, 0.47 parts of MgO, 0.43 parts of MnO2, lanthanum nitrate equivalent to 0.07 parts of La2O3, 0.98 parts of polystyrene - divinylbenzene microspheres (1.5 μm), and 3.02 parts of starch by weight, and stir in a mixer for 1 hour until evenly mixed;

[0122] Add 15.1 parts of deionized water to the obtained mixture, knead for 1 hour, take out, extrude and cut into particles with a diameter of 3 mm and a length of 5 - 10 mm, put them in an oven, bake at 50 °C for 10 hours, bake at 160 °C for 5 hours, and then place them in a muffle furnace, calcine at 400 °C for 3 hours, and calcine at 750 °C for 3 hours to obtain the finished catalyst.

[0123] The results of the evaluation of the most probable pore diameter, bulk density, and ethylbenzene dehydrogenation reaction performance of the dehydrogenation catalyst are shown in Table 1.

[0124] Example 6

[0125] (1) Weigh iron oxide red equivalent to 73.45 parts of Fe2O3, potassium hydroxide equivalent to 10.8 parts of K2O, sodium nitrate equivalent to 1.62 parts of Na2O, calcium hydroxide equivalent to 2.03 parts of CaO, 0.47 parts of MgO, 0.98 parts of polystyrene - divinylbenzene microspheres (1.5 μm), and 1.7 parts of deionized water by weight, and stir in a mixer for 1 hour until evenly mixed to obtain the first mixed wet powder;

[0126] (2) Mix cerium carbonate equivalent to 9.76 parts of CeO2, ammonium tungstate equivalent to 1.37 parts of WO3, 0.31 parts of MnO2, lanthanum nitrate equivalent to 0.19 parts of La2O3, and 3.02 parts of starch with 13.4 parts of deionized water to form a colloid or suspension;

[0127] (3) Blend the mixtures obtained in steps (1) and (2), knead for 1 hour, take out, extrude and cut into particles with a diameter of 3 mm and a length of 5 - 10 mm, put them in an oven, bake at 50 °C for 10 hours, bake at 160 °C for 5 hours, and then place them in a muffle furnace, calcine at 400 °C for 3 hours, and calcine at 750 °C for 3 hours to obtain the finished catalyst.

[0128] The most probable pore size, bulk density and ethylbenzene dehydrogenation reaction performance evaluation results of the dehydrogenation catalyst are shown in Table 1.

[0129] Comparative Example 1

[0130] The method of Example 1 is followed, except that only one pore-forming agent is included;

[0131] Specifically: red iron oxide, cerium carbonate, potassium hydroxide, sodium nitrate, ammonium tungstate, calcium hydroxide, MnO2, lanthanum nitrate and 3.02 parts of starch are stirred in a mixer for 1 hour until the mixture is uniformly mixed; 15.1 parts of deionized water are added to the resulting mixture, kneaded for 1 hour, taken out and extruded, and pelletized to obtain particles with a diameter of 3 mm and a length of 5-10 mm, put into an oven, bake at 50°C for 10 hours, bake at 160°C for 5 hours, then place in a muffle furnace, roast at 400°C for 3 hours, and roast at 750°C for 3 hours to obtain a finished catalyst.

[0132] Comparative Example 2

[0133] The method of Example 1 is followed, except that only one pore-forming agent is included;

[0134] Specifically, according to weight parts, weigh 73.45 parts of red iron oxide equivalent to Fe2O3, 9.76 parts of cerium carbonate equivalent to CeO2, 10.8 parts of potassium hydroxide equivalent to K2O, 1.62 parts of sodium nitrate equivalent to Na2O, 1.37 parts of ammonium tungstate equivalent to WO3, 2.03 parts of calcium hydroxide equivalent to CaO, 0.31 parts of MnO2, 0.19 parts of lanthanum nitrate equivalent to La2O3 and 0.98 parts of polystyrene-divinylbenzene microspheres (1.5 μm) and stir in a mixer for 1 hour until the mixture is uniformly mixed;

[0135] The obtained mixture was mixed with 15.1 parts of deionized water, kneaded for 1 hour, taken out, extruded and pelletized to obtain particles with a diameter of 3 mm and a length of 5-10 mm, placed in an oven, baked at 50°C for 10 hours and at 160°C for 5 hours, then placed in a muffle furnace, calcined at 400°C for 3 hours and at 750°C for 3 hours to obtain the finished catalyst.

[0136] The most probable pore size, bulk density and ethylbenzene dehydrogenation reaction performance evaluation results of the dehydrogenation catalyst are shown in Table 1.

[0137] Table 1

[0138]

[0139]

[0140] The above examples and comparative examples illustrate that by adding promoters of at least one Group VIIB metal oxide (MnO2, ReO2, Re2O7) and at least one rare earth metal oxide (La2O3, Gd2O3) in a certain proportion to the iron-alkali metal-cerium-tungsten-alkaline earth metal system, introducing a first pore-forming agent and a second pore-forming agent, and controlling the weight ratio of the Group VIIB metal oxide to the rare earth metal oxide, a catalyst with typical bimodal pore structure characteristics can be prepared. The hierarchical macroporous structure with bimodal distribution not only significantly reduces the bulk density of the catalyst, but also reduces the mass transfer resistance and improves the selectivity of the catalyst for vinyl aromatic hydrocarbons under low water ratio conditions. The catalyst prepared by this method is suitable for the industrial production of dehydrogenating alkyl aromatic hydrocarbons to vinyl aromatic hydrocarbons under low water ratio conditions.

[0141] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. 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 dehydrogenation catalyst comprises, by mass percentage: (a) 62 - 80% of Fe2O3; (b) at least one of 8 - 14% of alkali metal oxides; (c) 6 - 15% of CeO2; (d) 0.1 - 5% of WO3; (e) at least one of 0.2 - 6% of alkaline earth metal oxides; (f) at least one of 0.01 - 3% of Group VIIB metal oxides; (g) at least one of 0.01 - 2% of rare earth metal oxides; The dehydrogenation catalyst has a pore size presenting a bimodal distribution of the most probable pore sizes of 300 ± 200 nm and 1100 ± 300 nm.

2. The dehydrogenation catalyst according to claim 1, wherein the dehydrogenation catalyst has a pore size presenting a bimodal distribution of the most probable pore sizes of 300 ± 100 nm and 1100 ± 200 nm; and / or the bulk density of the dehydrogenation catalyst is 1.0 - 1.3 kg / L.

3. The dehydrogenation catalyst according to claim 2, wherein the dehydrogenation catalyst comprises: (a) 64 - 78% of Fe2O3; and / or (b) at least one of 10 - 13% of alkali metal oxides; and / or (c) 7 - 14% of CeO2; and / or (d) 0.3 - 3% of WO3; and / or (e) at least one of 0.5 - 5% of alkaline earth metal oxides; and / or (f) at least one of 0.1 - 2% selected from Group VIIB metal oxides; and / or (g) at least one of 0.05 - 1% selected from rare earth metal oxides; and / or in the dehydrogenation catalyst, the weight ratio of Group VIIB metal oxides to rare earth metal oxides is 0.05 - 5.

0.

4. The dehydrogenation catalyst according to claim 2 or 3, wherein the alkali metal oxide is selected from at least one of Li2O, Na2O, and K2O; preferably a combination of K2O with Li2O or Na2O, and preferably the mass ratio of Li2O or Na2O to K2O is 0.1 - 0.2; and / or the alkaline earth metal oxide is at least one of MgO, CaO, and SrO; and / or Group VIIB metal oxides are selected from at least one of MnO2, ReO2, and Re2O7; and / or the rare earth oxide is selected from at least one of La2O3 and Gd2O3.

5. The preparation method of the dehydrogenation catalyst according to any one of claims 1-4, characterized in that, The method comprises: mixing and granulating an Fe source, an alkali metal source, a Ce source, a W source, an alkaline earth metal source, a Group VIIB metal source, a rare earth metal source, a pore-forming agent, and optionally a solvent by one of wet granulation, dry granulation, tabletting, template agent method, foaming method, and gel method, drying, and removing the pore-forming agent; wherein the pore-forming agent comprises a first pore-forming agent and a second pore-forming agent; the first pore-forming agent is selected from at least one of synthetic polymer microsphere materials; the second pore-forming agent is selected from at least one of inorganic carbon materials, natural polymer materials and their products, naphthalene powder, paraffin wax, inorganic fillers, and ethyl silicate.

6. The preparation method according to claim 5, wherein the inorganic carbon material is selected from at least one of carbon powder, carbon spheres, carbon nanotubes, carbon fibers, activated carbon, carbon black, foam carbon, and graphite; and / or The natural polymer materials and their products are selected from at least one of starch, protein, cellulose, cellulose ether, alginate, gelatin, chitosan, agarose, and dextran; and / or Among the synthetic polymer microsphere materials, the synthetic polymer is selected from at least one of polyvinylpyrrolidone, polyacrylamide, sodium polyacrylate, polystyrene, polymethyl methacrylate, polyvinyl alcohol, styrene-divinylbenzene copolymer, polyethylene glycol, polyacrylic acid, poly(ethylene oxide), poly(propylene carbonate), polylactic acid, polyurethane, poly(propylene carbonate), polyvinylpyrrolidone, polyethylene-vinyl acetate, polydimethylsiloxane, poly(urea-formaldehyde), polyacrylonitrile, polysiloxane, and poly(lactic-co-glycolic acid); and / or The inorganic filler is selected from at least one of kaolin, diatomite, cement, montmorillonite, halloysite, metahalloysite, saponite, rectorite, sepiolite, attapulgite, hydrotalcite, bentonite, potassium silicate, silicate borate, pseudoboehmite, silica spheres, silicon carbide, ammonium carbonate, ammonium bicarbonate, and urea; and / or The solvent is selected from at least one of water, alcohols, esters, ketones, ethers, or hydrocarbons, preferably a mixed solvent of water and alcohols; and / or The method for removing the pore-forming agent is selected from one or more of alkali etching, calcination, and solvent dissolution; The drying conditions include: a temperature of 30 - 200 °C and a time of 6 - 24 h; preferably, drying at 50 - 100 °C for 4 - 16 h, and then raising the temperature to 120 - 180 °C and drying for 2 - 8 h; and / or Based on the total mass of the metal oxides of each metal source, the dosage of the pore-forming agent is 0.1% - 8% of the metal source, preferably 0.5 - 6%; Preferably, the mass ratio of the first pore-forming agent to the second pore-forming agent is 1:20 - 2:

1.

7. According to the preparation method described in claim 6, wherein, The particle size range of the synthetic polymer microsphere material is 200 nm - 5 μm, preferably 500 nm - 2 μm; and / or The calcination conditions include: a temperature of 200 - 1000 °C and a time of 2 - 12 hours; preferably, calcining at 300 - 500 °C for 1 - 6 hours, and then raising the temperature to 600 - 900 °C and calcining for 1 - 6 hours.

8. The preparation method according to claim 5 or 6, wherein The preparation method of the dehydrogenation catalyst includes: (1) Mixing an Fe source, an alkali metal source, an alkaline earth metal source, a first pore-forming agent, and a solvent to obtain a first mixed wet powder; (2) Mixing a Ce source, a W source, a Group VIIB metal source, a rare earth metal source with a second pore-forming agent and a solvent to obtain a second mixed colloid or suspension; (3) Co-mixing the first mixed wet powder with the second mixed colloid or suspension, kneading into shape, drying, and calcining; the first pore-forming agent is selected from at least one of polystyrene, styrene-divinylbenzene copolymer, polyvinylpyrrolidone, polymethyl methacrylate, polyvinyl alcohol, polyethylene glycol, and poly(lactic-co-glycolic acid) (poly(lactide-co-glycolide)); The second pore-forming agent is selected from at least one of starch, cellulose, cellulose ether, carbon powder, and graphite.

9. The application of the dehydrogenation catalyst according to any one of claims 1 - 4 in the dehydrogenation of alkyl aromatics.

10. A method for dehydrogenating alkyl aromatic hydrocarbons, characterized in that, The method includes: Under the conditions of dehydrogenation of alkylaromatics, contacting an alkylaromatic, water with a catalyst; the catalyst comprises the dehydrogenation catalyst according to any one of claims 1-4; Preferably, the weight ratio of water to the alkylaromatic is 0.9-1.3; and / or The hourly space velocity of the alkylarene is 0.1 - 2 h -1 ; and / or The dehydrogenation reaction conditions include: a temperature of 580-650 °C and a pressure of 20 kPaA-atmospheric pressure; Preferably, the alkylaromatic is ethylbenzene.

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