Dehydrogenation catalyst, preparation method and application thereof, and method for preparing butadiene by butene oxidative dehydrogenation

Abstract

The present application relates to a dehydrogenation catalyst, a preparation method and application thereof, and a method for preparing butadiene by butene oxidative dehydrogenation, and provides a dehydrogenation catalyst, which comprises: a spinel phase, an alpha-iron oxide phase, and an antioxidant alloy component; the antioxidant alloy component is selected from at least three of IVB group, VIB group and VIII group; the present application introduces hydrogenation active centers by adding an antioxidant metal alloy component in the spinel structure, and hydrogenation reaction is generated by using a small amount of hydrogen generated in the reaction to inhibit the generation of aldehydes, so that the content of aldehydes in the organic by-products of the dehydrogenation product is greatly reduced, and the selectivity of the catalyst is improved.

Description

Technical Field

[0001] This invention relates to dehydrogenation catalysts, their preparation methods and applications, and a method for the oxidative dehydrogenation of butene to butadiene. Background Technology

[0002] Butadiene is a very important basic chemical raw material and a crucial monomer for the production of polymer synthetic materials. It can be copolymerized with various compounds to produce various synthetic rubbers such as styrene-butadiene rubber and nitrile rubber, as well as synthetic resins such as acrylonitrile-butadiene-styrene terpolymer resins. It can also be used to produce other products such as adiponitrile (Nylon 66 monomer), sulfolane, anthraquinone, and tetrahydrofuran.

[0003] Currently, butadiene is mainly produced through two methods: refinery steam cracking to ethylene co-production with C4 extraction and separation, and butene oxidation. Approximately 97% of the world's butadiene production capacity utilizes the cracking C4 extraction process, which is economically advantageous. However, due to the rapid development of shale gas extraction technology in recent years, the production of butadiene from cracking C4 extraction will decrease. From 2000 to 2010, the proportion of naphtha-based ethylene production units decreased from 55% to 47% of all ethylene units. With the global demand for butadiene continuously increasing, cracking units can hardly meet the demand. Butene oxidative dehydrogenation to butadiene technology has once again become a research hotspot. This technology can not only reduce dependence on petroleum resources but also fill the gap in the butadiene market.

[0004] Catalysts used for the oxidative dehydrogenation of butene mainly fall into three categories: Mo-Bi systems, Sn-P-Li systems, and Fe salt systems. Iron-based catalysts, with their advantages of mild reaction conditions, high catalytic activity, and more specific selectivity, are currently the most widely used. USP3270080 discloses AB₂O₄ (where A is generally Mg). 2+ Zn 2+ Co 2+ and Ni 2+ Divalent metal ions, B is Fe 3+ (Ionic) Iron-based spinel butene oxidative dehydrogenation catalysts to butadiene are used, but their performance is not very stable. USP3450788 and USP3595810 disclose the introduction of Cr... 3+ It can improve the stability of the catalyst. Yanshan Petrochemical Company's synthetic rubber plant has put into production a chromium-free iron-based BO2 catalyst for the oxidative dehydrogenation of butene to butadiene in an adiabatic fixed bed.

[0005] Although the above technologies have achieved great economic benefits in industrial applications, and the activity of the catalysts and the selectivity of the target products have reached a high level, the high aldehyde products in the butene oxidative dehydrogenation products during the production process make the subsequent heat exchange units prone to blockage, which has a significant impact on production operation.

[0006] Therefore, there is still a need in the field to develop a catalyst for the oxidative dehydrogenation of butene to prepare butadiene, to further reduce the content of organic by-products in the dehydrogenation products and improve the selectivity of the catalyst. Summary of the Invention

[0007] The purpose of this invention is to overcome the problem of high aldehyde content in the oxidative dehydrogenation products of existing technologies, and to provide a dehydrogenation catalyst and its preparation method. This catalyst introduces hydrogenation active centers by adding an antioxidant metal alloy component to the spinel phase. It uses the small amount of hydrogen generated in the reaction to inhibit the formation of aldehydes through hydrogenation. When applied to the oxidative dehydrogenation of butene to butadiene, it has the advantages of low aldehyde content in the organic by-products of dehydrogenation and high catalyst selectivity.

[0008] To achieve the above objectives, the present invention provides a dehydrogenation catalyst comprising: a spinel phase, an α-iron oxide phase, and an antioxidant alloy component; wherein the antioxidant alloy component is selected from at least three of Group IVB, Group VIB, and Group VIII.

[0009] The second aspect of the present invention provides a method for preparing the catalyst described herein, the method comprising: (1) co-precipitating an iron source, an inorganic salt required to form a spinel phase, and an alkali source, aging, washing, and obtaining a first slurry; (2) optionally contacting an antioxidant alloy component with an alkali source and washing until neutral; (3) contacting the antioxidant alloy component with the first slurry in step (1) and a high molecular weight organic compound to obtain a second slurry, ball milling, drying and shaping, and calcining; (4) contacting the calcined sample in step (3) under a mixed atmosphere of H2 and water vapor.

[0010] A third aspect of the present invention provides the application of the catalyst described herein in the oxidative dehydrogenation of low-carbon olefins.

[0011] A fourth aspect of the present invention provides a method for the oxidative dehydrogenation of butene to produce butadiene, the method comprising: reacting butene, a diluent, an oxidant and a catalyst in a contact reaction; wherein the catalyst comprises the catalyst described in the present invention.

[0012] Through the above technical solution, the present invention has the following beneficial effects:

[0013] This invention introduces hydrogenation active centers by adding antioxidant metal alloy components to the spinel phase. The small amount of hydrogen generated during the reaction is used to inhibit the formation of aldehydes, which greatly reduces the content of aldehydes in the organic by-products of dehydrogenation and improves the selectivity of the catalyst. Detailed Implementation

[0014] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0015] The present invention provides a dehydrogenation catalyst comprising: a spinel phase, an α-iron oxide phase, and an antioxidant alloy component; wherein the antioxidant alloy component is selected from at least three of Group IVB, Group VIB, and Group VIII.

[0016] In this invention, there are no special requirements for each component in the antioxidant alloy composition. As long as each component contains at least three of the aforementioned IVB, VIB and VIII groups, the purpose of this invention can be achieved. The content of each component in the alloy is not less than 5% by weight, preferably not less than 10% by weight.

[0017] According to a preferred embodiment of the present invention, the content of spinel phase is 60-90 wt%, preferably 70-80 wt%, based on 100 wt% of catalyst.

[0018] According to a preferred embodiment of the present invention, the content of the α-iron oxide phase is 10-40 wt%, preferably 20-30 wt%, based on 100 wt% of the catalyst.

[0019] According to a preferred embodiment of the present invention, the content of the antioxidant alloy component is 0.1-5 wt%, preferably 1-3 wt%, based on 100 wt% of the catalyst.

[0020] By employing the aforementioned preferred embodiments, the content of aldehydes in the organic byproducts of dehydrogenation can be reduced, thereby improving the selectivity of the catalyst.

[0021] In this invention, the particle size of the antioxidant alloy component can be selected over a wide range. According to a preferred embodiment of the invention, the particle size of the antioxidant alloy component is 1-150 micrometers, preferably 2-100 micrometers. By adopting the aforementioned preferred embodiment, the hydrogenation active centers of the catalyst can be improved, thereby reducing the formation of aldehydes in the product.

[0022] In this invention, the range of selectable antioxidant alloy components is relatively wide. According to a preferred embodiment of the invention, the antioxidant alloy component is selected from at least three of Cr, Ni, Ti, Rh, Pt, and Re. Preferably, the antioxidant alloy component is a Ni-Cr-Ti alloy and / or a Ni-Pt-Cr alloy. By employing the aforementioned preferred embodiment, the effect of inhibiting aldehyde formation during the reaction with hydrogen can be improved, and the catalyst selectivity can be enhanced.

[0023] In this invention, the density of acid centers on the catalyst surface can be selected within a wide range. According to a preferred embodiment of the invention, the density of acid centers on the catalyst surface is 90-300 μmmol / g, preferably 150-200 μmol / g. By adopting the aforementioned preferred embodiment, the hydrogenation active centers of the catalyst can be increased, thereby reducing the formation of aldehydes in the product.

[0024] In this invention, the pore volume of the catalyst can be selected over a wide range. According to a preferred embodiment of the invention, the pore volume of the catalyst is 0.1-1 ml / g, preferably 0.2-0.3 ml / g. By adopting the aforementioned preferred embodiment, the content of aldehydes in the organic byproducts of dehydrogenation can be reduced, and the selectivity of the catalyst can be improved.

[0025] In this invention, the average pore size of the catalyst can be selected over a wide range. According to a preferred embodiment of the invention, the average pore size of the catalyst is 10-60 nm, preferably 20-22 nm. By employing the aforementioned preferred embodiment, the content of aldehydes in the organic byproducts of dehydrogenation can be reduced, thereby improving the selectivity of the catalyst.

[0026] In this invention, the specific surface area of ​​the catalyst can be selected from a wide range. According to a preferred embodiment of this invention, the specific surface area of ​​the catalyst is 20-80 m². 2 / g, preferably 35-45m 2 / g. By employing the aforementioned preferred embodiments, the hydrogenation active sites of the catalyst can be increased, thereby reducing the formation of aldehydes in the product.

[0027] According to a preferred embodiment of the present invention, the spinel structure satisfies the chemical formula: A x Fe₂O₄, where A is selected from at least one of Ca, Mn, Co, Ni, Cu, Zn, Cd, Hg, Mg, Sn, Al, Co, Bi, Ti, and V, preferably at least three of Ca, Mn, Co, Ni, Cu, Zn, Cd, Hg, Mg, Sn, Al, Co, Bi, Ti, and V; and x satisfies the valence requirement. Using the aforementioned preferred embodiments, the content of aldehydes in the organic byproducts of dehydrogenation can be reduced, and the selectivity of the catalyst can be improved.

[0028] All dehydrogenation catalysts with the aforementioned characteristics can be used in this invention, and there are no special requirements for their preparation methods. In this invention, a method for preparing a dehydrogenation catalyst is provided, which includes: (1) co-precipitating an iron source, an inorganic salt required to form a spinel phase, and an alkali source, aging, washing, and obtaining a first slurry; (2) optionally contacting an antioxidant alloy component with an alkali source and washing until neutral; (3) contacting the antioxidant alloy component with the first slurry in step (1) and a high molecular weight organic compound to obtain a second slurry, ball milling, drying and shaping, and calcining; (4) contacting the sample calcined in step (3) in a mixed atmosphere of H2 and water vapor.

[0029] In this invention, in order to obtain a uniformly mixed substance, ball milling and other operations are performed as needed. These operations are well known to those skilled in the art and can be performed with reference to existing technologies.

[0030] In this invention, part of the added iron source is used to form the spinel phase and part is used to form the α-iron oxide phase. The structure of the antioxidant alloy component in this invention remains unchanged before and after preparation, and it is still an alloy structure.

[0031] In this invention, the solvent has no special requirements and is well known to those skilled in the art. Deionized water is used as an example, but this does not limit the scope of the invention. The amount of deionized water can be adjusted according to actual needs, but this does not limit the scope of the invention.

[0032] In this invention, the conditions and time for heating, slow dripping, and stirring are flexibly selected according to the type and amount of the substance. This is a well-known operating method for those skilled in the art, and will not be described in detail here.

[0033] In this invention, the washing step (1) has no special requirements and is described illustratively, but does not limit the scope of this invention. Deionized water is used as the solvent for washing, and there are no special requirements for the amount of deionized water used, as long as it meets the experimental requirements. This operation is well known to those skilled in the art, and will not be described in detail here.

[0034] In this invention, the range of high molecular weight organic compounds is relatively wide. According to a preferred embodiment of the invention, the high molecular weight organic compound is at least one selected from polyethylene glycol, starch, cellulose, and sucrose. Cellulose is used as an example in the embodiments, but this does not limit the scope of the invention. By adopting the aforementioned preferred embodiments, the hydrogenation active sites of the catalyst can be increased, thereby reducing the formation of aldehydes in the product.

[0035] In this invention, the alkali source has no special requirements. According to a preferred embodiment of the invention, the alkali source is selected from at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and ammonia water. Ammonia water is used as an example in the embodiments, but this does not limit the scope of the invention. By adopting the aforementioned preferred embodiments, the hydrogenation active centers of the catalyst can be increased, thereby reducing the formation of aldehydes in the product.

[0036] In this invention, the mass of the high molecular weight organic compound, calculated as 100 wt% of a mixture of high molecular weight organic compound, inorganic salts required to form the spinel phase, iron source, and antioxidant alloy components, has a wide range of selectable mass. According to a preferred embodiment of the invention, the mass of the high molecular weight organic compound, calculated as 100 wt% of a mixture of high molecular weight organic compound, inorganic salts required to form the spinel phase, iron source, and antioxidant alloy components, is 0.1-3 wt%, preferably 1.5-3 wt%. By employing the aforementioned preferred embodiment, the hydrogenation active centers of the catalyst can be improved, thereby reducing the formation of aldehydes in the product.

[0037] In this invention, based on a 100wt% mixture of high molecular weight organic matter, inorganic salts required to form the spinel structure, iron source, and antioxidant alloy components, the mass of the inorganic salts required to form the spinel structure can be selected within a wide range. According to a preferred embodiment of the invention, based on a 100wt% mixture of high molecular weight organic matter, inorganic salts required to form the spinel structure, iron source, and antioxidant alloy components, the mass of the inorganic salts required to form the spinel structure is 5-30wt%, preferably 15-20wt%. By employing the aforementioned preferred embodiment, the hydrogenation active centers of the catalyst can be increased, thereby reducing the formation of aldehydes in the product.

[0038] In this invention, based on a 100wt% mixture of high molecular weight organic matter, inorganic salts required to form the spinel structure, an iron source, and antioxidant alloy components, the mass of the iron source can be selected from a wide range. According to a preferred embodiment of the invention, based on a 100wt% mixture of high molecular weight organic matter, inorganic salts required to form the spinel structure, an iron source, and antioxidant alloy components, the mass of the iron source is 40-90wt%, preferably 70-80wt%. By employing the aforementioned preferred embodiment, the hydrogenation active centers of the catalyst can be increased, thereby reducing the formation of aldehydes in the product.

[0039] In this invention, based on a 100wt% mixture of high molecular weight organic matter, inorganic salts required to form the spinel structure, iron source, and antioxidant alloy components, the mass of the antioxidant alloy component can be selected within a wide range. According to a preferred embodiment of the invention, based on a 100wt% mixture of high molecular weight organic matter, inorganic salts required to form the spinel structure, iron source, and antioxidant alloy components, the mass of the alloy is 0.1-5wt%, preferably 0.3-0.6wt%. By employing the aforementioned preferred embodiment, the hydrogenation active centers of the catalyst can be improved, thereby reducing the formation of aldehydes in the product.

[0040] According to a preferred embodiment of the present invention, the temperature of the co-precipitation is 10-50°C, preferably 20-40°C.

[0041] According to a preferred embodiment of the present invention, the pH value of the coprecipitation is 8-11, preferably 8.5-9.8.

[0042] By employing the aforementioned preferred embodiments, the hydrogenation active centers of the catalyst can be increased, thereby reducing the formation of aldehydes in the product.

[0043] In this invention, there are no special requirements for the aging conditions in step (1). According to a preferred embodiment of the invention, the aging time is 0.5-4 hours. The example uses 2 hours as an example, but this does not limit the scope of the invention. By adopting the aforementioned preferred embodiment, the content of aldehydes in the organic byproducts of dehydrogenation can be reduced, and the selectivity of the catalyst can be improved.

[0044] In this invention, in step (2), there are no special requirements for the conditions under which the alkali source is brought into contact with the antioxidant alloy component for purification, as needed. The purpose is to purify the alloy, which is well known to those skilled in the art. The example uses 2.5 mol / L NaOH solution to leach industrial-grade alloy powder as an illustration, but this does not limit the scope of the invention.

[0045] In this invention, the washing operation in step (2) has no special requirements and is well known to those skilled in the art. In the example, anhydrous ethanol is used to wash several times until neutral and then stored in anhydrous ethanol as an example, but this does not limit the scope of the invention.

[0046] In this invention, in step (3), after obtaining the second slurry, before drying and molding, the mixed slurry can be stirred and ball-milled (colloidal) at room temperature for, for example, 2 hours. The purpose of this step is to mix it evenly. This operation can be carried out with reference to the prior art.

[0047] In this invention, the solid content of the second slurry in step (3) can be selected within a wide range. According to a preferred embodiment of the invention, the solid content of the second slurry is 5-40 wt%. The example uses 30 wt% as an example, but this does not limit the scope of the invention. By adopting the aforementioned preferred embodiment, the hydrogenation active centers of the catalyst can be increased, thereby reducing the formation of aldehydes in the product.

[0048] In this invention, the solid content of the second slurry is controlled by the amount of deionized water added.

[0049] In this invention, there are no special requirements for the molding method in step (3). According to the preferred embodiment of this invention, the molding method is spray drying molding or compression molding. Spray drying molding is used as an example in the embodiments, but it does not limit the scope of this invention.

[0050] In this invention, after spray drying and before calcination, the material that has been formed into microspheres in the spray dryer can be dried at 90°C for 12 hours.

[0051] According to a preferred embodiment of the invention, the roasting is carried out in an air atmosphere.

[0052] According to a preferred embodiment of the present invention, the calcination temperature is 550-900℃, preferably 620-750℃.

[0053] According to a preferred embodiment of the present invention, the roasting time is 4-18 hours, with 6 hours being used as an example in the embodiments, but this does not limit the scope of the present invention.

[0054] By employing the aforementioned preferred embodiments, the hydrogenation active centers of the catalyst can be increased, thereby reducing the formation of aldehydes in the product.

[0055] In this invention, in step (4), the volume ratio of H2 to water vapor in the mixed atmosphere can be selected within a wide range. According to a preferred embodiment of the invention, the H2:water vapor ratio in the mixed atmosphere is 1:2-1:20, preferably 1:5-1:10. The example uses H2:water = 1:8 as an example, but this does not limit the scope of the invention. By adopting the aforementioned preferred embodiment, the hydrogenation active centers of the catalyst can be increased, thereby reducing the formation of aldehydes in the product.

[0056] In this invention, there are no special requirements for the contact conditions in step (4). This is an illustrative example, but it does not limit the scope of the invention.

[0057] According to a preferred embodiment of the invention, the contact temperature is 300-500°C, preferably 350-420°C. The example is illustratively illustrated with a contact temperature of 400°C, but this does not limit the scope of the invention.

[0058] According to a preferred embodiment of the invention, the contact time is 2-6 hours. An example of a 4-hour contact time is provided, but this does not limit the scope of the invention.

[0059] By employing the aforementioned preferred embodiments, the hydrogenation active centers of the catalyst can be increased, thereby reducing the formation of aldehydes in the product.

[0060] This invention provides the application of the catalyst described herein in the preparation of dehydrogenation of low-carbon olefins, preferably in the oxidative dehydrogenation process of low-carbon monoolefins.

[0061] This invention provides a method for the oxidative dehydrogenation of butene to produce butadiene, the method comprising: reacting butene, a diluent, an oxidant and a catalyst in a contact reaction; the catalyst comprising the catalyst described in this invention.

[0062] In this invention, there are no special requirements for the molar ratio of the oxidant to butene. According to a preferred embodiment of the invention, the molar ratio of the oxidant to butene is 0.4-1. In the examples, the molar ratio of the oxidant to butene is 0.7, which is illustrative but does not limit the scope of the invention.

[0063] In this invention, the molar ratio of the diluent to butene is not particularly required. According to a preferred embodiment of the invention, the molar ratio of the diluent to butene is 2-16. An example of a molar ratio of 12 is used as an illustration, but this does not limit the scope of the invention. The type of diluent is not particularly required; for example, water vapor.

[0064] In this invention, there are no special requirements for the conditions of the contact reaction.

[0065] According to a preferred embodiment of the invention, the temperature of the contact reaction is 320-560°C, with 420°C being used as an example in the embodiments, but this does not limit the scope of the invention.

[0066] According to a preferred embodiment of the invention, the pressure of the contact reaction is 0.01-0.8 MPa, with 0.03 MPa being used as an example in the embodiments, but this does not limit the scope of the invention.

[0067] According to a preferred embodiment of the present invention, the butene volume hourly space velocity in the contact reaction is 300-800 h⁻¹. -1 In the example, 400h -1 This is an illustrative example, but does not limit the scope of the invention.

[0068]

[0069]

[0070] (Ai —Peak area of ​​component i in the sample; R i —Relative mass correction factor of component i to butadiene.

[0071] In this invention, the composition of the catalyst—spinel phase, α-iron oxide phase, and antioxidant alloy component—was determined by X-ray diffraction testing, and the composition of each component was determined by elemental analysis.

[0072] The particle size of the antioxidant alloy component was obtained by measuring the particle size distribution using a particle size analyzer.

[0073] The density of acid sites on the catalyst surface was obtained by NH3-TPD (temperature programmed desorption of ammonia).

[0074] The pore volume, average pore size, and specific surface area of ​​the catalyst were obtained by BET specific surface area detection method.

[0075] Example 1

[0076] (1) Dissolve 3.75 g zinc nitrate, 6.87 g cobalt nitrate, 29.54 g magnesium nitrate and 179.18 g ferric nitrate in 3 L of distilled water, add 15 wt% ammonia solution dropwise while stirring rapidly, the precipitation endpoint pH = 9.0, stir at 30 °C for 30 minutes, let stand at room temperature for 2 hours, filter and wash the resulting slurry;

[0077] (2) Using a 2.5 mol / L NaOH solution, 1.00 g of industrial-grade Ni-Cr-Ti (Ni:Cr:Ti = 6:2.5:1.5 (mass ratio)) alloy powder (particle size of 50 micrometers) was leached, and then washed several times with anhydrous ethanol until neutral. The prepared sample was stored in anhydrous ethanol and added to the slurry of the previous step. 5 g of cellulose was added to the above active component slurry, and the solid content was controlled to be 30 wt%. The mixture was stirred for 10 minutes and ball-milled (colloidal) at room temperature for 2 hours to obtain a slurry. Microspheres were formed by spray drying and then dried at 90°C for 12 hours. Finally, the sample was calcined in a muffle furnace at 700°C for 6 hours. The obtained sample was then treated at 400°C for 4 hours in an atmosphere with a H2:H2O volume ratio of 1:8 to obtain a catalyst sample. The parameters are shown in Table 2.

[0078] (3) Using butene, air and steam as raw materials, the reaction was carried out at a temperature of 420℃, a pressure of 0.03MPa and a volume hourly space velocity of 400h. -1 The experimental results under the conditions of an oxygen-to-olefin molar ratio of 0.7 and a water-to-olefin molar ratio of 12 are shown in Table 1.

[0079] Example 2

[0080] (1) Dissolve 2.39 g of nickel nitrate, 12.98 g of cobalt nitrate, 23.84 g of magnesium nitrate and 164.86 g of ferric nitrate in 3 L of distilled water, add 15 wt% ammonia solution dropwise while stirring rapidly, the precipitation endpoint pH = 8.5, stir at 40 °C for 30 minutes, let stand at room temperature for 2 hours, filter and wash the resulting slurry;

[0081] (2) Using a 2.5 mol / L NaOH solution, 1.00 g of industrial-grade Ni-Cr-Ti (Ni:Cr:Ti = 6:2.5:1.5) alloy powder (particle size of 100 μm) was leached, and then washed several times with anhydrous ethanol until neutral. The prepared sample was stored in anhydrous ethanol and added to the slurry of the previous step. 5 g of cellulose was added to the above active component slurry, and the solid content was controlled to be 30 wt%. The mixture was stirred for about 10 minutes and ball milled (colloidal) at room temperature for 2 hours to obtain the slurry. Microspheres were formed by spray drying and then dried at 90 °C for 12 hours. Finally, the sample was calcined in a muffle furnace at 750 °C for 6 hours. The obtained sample was then treated at 400 °C for 4 hours in an atmosphere with a volume ratio of H2:H2O of 1:8 to obtain the catalyst sample. The parameters are shown in Table 2.

[0082] (3) Using butene, air and steam as raw materials, the reaction was carried out at a temperature of 420℃, a pressure of 0.03MPa and a volume hourly space velocity of 400h. -1 The experimental results under the conditions of an oxygen-to-olefin molar ratio of 0.7 and a water-to-olefin molar ratio of 12 are shown in Table 1.

[0083] Example 3

[0084] (1) Dissolve 1.65 g zinc nitrate, 4.68 g copper nitrate, 3.64 g nickel nitrate, 21.98 g magnesium nitrate and 141.66 g ferric nitrate in 3 L of distilled water, add 15 wt% ammonia solution dropwise while stirring rapidly, the precipitation endpoint pH = 9.0, stir at 20 °C for 30 minutes, let stand at room temperature for 2 hours, filter and wash the resulting slurry;

[0085] (2) Using a 2.5 mol / L NaOH solution, 1.00 g of industrial-grade Ni-Pt-Cr (Ni:Pt:Cr = 6.5:1.5:2.5) alloy powder (particle size of 80 micrometers) was leached, and then washed several times with anhydrous ethanol until neutral. The prepared sample was stored in anhydrous ethanol and added to the slurry of the previous step. 5 g of cellulose was added to the above active component slurry, and the solid content was controlled to be 30 wt%. The mixture was stirred for about 10 minutes and ball milled (colloidal) at room temperature for 2 hours to obtain the slurry. Microspheres were formed by spray drying and then dried at 90°C for 12 hours. Finally, the sample was calcined in a muffle furnace at 620°C for 6 hours. The obtained sample was then treated at 400°C for 4 hours in an atmosphere with a H2:H2O volume ratio of 1:8 to obtain the catalyst sample. The parameters are shown in Table 2.

[0086] (3) Using butene, air and steam as raw materials, the reaction was carried out at a temperature of 420℃, a pressure of 0.03MPa and a volume hourly space velocity of 400h. -1 The experimental results under the conditions of an oxygen-to-olefin molar ratio of 0.7 and a water-to-olefin molar ratio of 12 are shown in Table 1.

[0087] Example 4

[0088] All conditions are the same as in Example 1, except that the ingredients in step (1) are: 1.39 g zinc nitrate, 4.68 g cobalt nitrate, 24.96 g magnesium nitrate and 158.64 g ferric nitrate. The parameters are shown in Table 2.

[0089] The experimental results are shown in Table 1.

[0090] Example 5

[0091] All conditions are the same as in Example 1, except that in step (2): 1.00 g of industrial-grade Ni-Cr-Ti alloy powder (particle size of 150 micrometers), parameters are shown in Table 2;

[0092] The experimental results are shown in Table 1.

[0093] Example 6

[0094] All conditions are the same as in Example 1, except that in step (2), the furnace is calcined at 900°C for 12 hours. The parameters are shown in Table 2.

[0095] The experimental results are shown in Table 1.

[0096] Example 7

[0097] All conditions are the same as in Example 1, except that in step (1), the following ingredients are added: 13.84 g magnesium nitrate, 23.49 g tin chloride and 164.86 g ferric nitrate are dissolved in 3 L of distilled water. The parameters are shown in Table 2.

[0098] The experimental results are shown in Table 1.

[0099] Example 8

[0100] All conditions are the same as in Example 1, except that the pH at the precipitation endpoint in step (1) is 10.5; parameters are shown in Table 2.

[0101] The experimental results are shown in Table 1.

[0102] Example 9

[0103] All conditions are the same as in Example 1, except that the catalyst is not treated with a mixed atmosphere of H2:H2O. The parameters are shown in Table 2.

[0104] The experimental results are shown in Table 1.

[0105] Comparative Example 1

[0106] (1) Dissolve 3.75 g zinc nitrate, 6.87 g cobalt nitrate, 29.54 g magnesium nitrate and 179.18 g ferric nitrate in 3 L of distilled water, add 15 wt% ammonia solution dropwise while stirring rapidly, the precipitation endpoint pH = 9.0, stir at 50 °C for 30 minutes, let stand at room temperature for 2 hours, filter and wash the resulting slurry;

[0107] (2) The above active component slurry was controlled with a solid content of 30wt%, stirred for about 10 minutes, and ball-milled at room temperature for 2 hours to obtain a slurry. The slurry was then formed into microspheres by spray drying, and finally dried at 90℃ for 12 hours and then transferred to a muffle furnace for calcination for 6 hours at a furnace temperature of 750℃ to obtain a catalyst sample. The parameters are shown in Table 2.

[0108] (3) Using butene, air and steam as raw materials, the reaction was carried out at a temperature of 420℃, a pressure of 0.03MPa and a volume hourly space velocity of 400h. -1 The experimental results under the conditions of an oxygen-to-olefin molar ratio of 0.7 and a water-to-olefin molar ratio of 12 are shown in Table 1.

[0109] Comparative Example 2

[0110] All conditions are the same as in Example 1, except that: the experimental results of leaching 1.25 grams of industrial-grade Sn-Sb alloy powder (particle size of 50 micrometers) in step (2) are shown in Table 1.

[0111] Table 1

[0112] Butene conversion rate % Butadiene selectivity % % of acetaldehyde byproduct in aqueous phase hydrogen / % Example 1 82.45 93.54 0.135 0.86 Example 2 81.97 93.49 0.143 0.92 Example 3 82.04 93.28 0.146 0.89 Example 4 81.13 93.20 0.162 1.05 Example 5 81.43 93.21 0.158 1.02 Example 6 81.95 93.19 0.165 1.12 Example 8 81.76 93.24 0.172 1.23 Example 9 81.26 93.15 0.263 1.56 Comparative Example 1 82.36 93.05 0.316 1.94 Comparative Example 2 80.51 92.58 0.308 1.83

[0113] As can be seen from the results in Table 1, the addition of an antioxidant metal alloy component to the spinel structure in this invention has a significantly better effect in inhibiting the formation of aldehydes.

[0114] Table 2

[0115]

[0116] 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 inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A dehydrogenation catalyst, characterized in that, The catalyst comprises: spinel phase, α-iron oxide phase, and antioxidant alloy components; Based on 100wt% of the catalyst, the content of spinel phase is 60-90wt%, the content of α-iron oxide phase is 10-40wt%, and the content of antioxidant alloy component is 0.1-5wt%. The antioxidant alloy composition is a Ni-Cr-Ti alloy and / or a Ni-Pt-Cr alloy; The spinel phase satisfies the chemical formula: A x Fe2O4, wherein A is selected from at least one of Ca, Mn, Co, Ni, Cu, Zn, Cd, Hg, Mg, and Sn, and the value of x satisfies the requirements of valence.

2. The catalyst according to claim 1, wherein, Based on 100wt% of catalyst, The content of spinel phase is 70-80 wt%; and / or The content of α-iron oxide phase is 20-30 wt%; and / or The content of the antioxidant alloy component is 1-3 wt%; and / or The particle size of the antioxidant alloy component is 1-150 micrometers; and / or The density of acid centers on the catalyst surface is 90-300 μmmol / g; and / or The catalyst has a pore volume of 0.1-1 ml / g; and / or The catalyst has an average pore size of 10-60 nm; and / or The catalyst has a specific surface area of ​​20-80 m². 2 / g.

3. The catalyst according to claim 2, wherein, Based on 100wt% of catalyst, The particle size of the antioxidant alloy component is 2-100 micrometers; and / or The density of acid centers on the catalyst surface is 150-200 μmol / g; and / or The catalyst has a pore volume of 0.2-0.3 ml / g; and / or The catalyst has an average pore size of 20-22 nm; and / or The catalyst has a specific surface area of ​​35-45 m². 2 / g.

4. The catalyst according to claim 1, A is selected from at least three of Ca, Mn, Co, Ni, Cu, Zn, Cd, Hg, Mg, and Sn.

5. A method for preparing the catalyst according to any one of claims 1-4, characterized in that, The method includes: (1) The iron source, the inorganic salt required to form the spinel phase and the alkali source are co-precipitated, aged, washed and the first slurry is obtained; (2) Selectively contact the antioxidant alloy components with an alkali source and wash until neutral; (3) The antioxidant alloy component is contacted with the first slurry in step (1) and high molecular weight organic matter to obtain a second slurry, which is then ball-milled, dried and shaped, and calcined. (4) The sample after calcination in step (3) is brought into contact with a mixed atmosphere of H2 and water vapor.

6. The method according to claim 5, wherein, The high molecular weight organic compound is at least one of polyethylene glycol, starch, cellulose, and sucrose; and / or The alkali source is selected from at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and ammonia water.

7. The method according to claim 5, wherein, Based on a 100wt% mixture of high molecular weight organic matter, inorganic salts required to form the spinel phase, iron source, and antioxidant alloying components, The mass of the high molecular weight organic compound is 0.1-3 wt%; and / or The inorganic salt required to form the spinel phase is 5-30 wt% by mass; and / or The iron source has a mass of 40-90 wt%; and / or The antioxidant alloy component has a mass of 0.1-5 wt%. and / or The conditions for the coprecipitation include: Temperature 10-50℃; and / or pH 8-11; and / or The aging conditions include a time of 0.5-4 hours.

8. The method according to claim 7, wherein, Based on a 100wt% mixture of high molecular weight organic matter, inorganic salts required to form the spinel phase, iron source, and antioxidant alloying components, The mass of the high molecular weight organic compound is 1.5-3 wt%; and / or The inorganic salt required to form the spinel phase is 15-20 wt% by mass; and / or The mass of the iron source is 70-80 wt%; and / or The antioxidant alloy component has a mass of 0.3-0.6 wt%. and / or The conditions for the coprecipitation include: The temperature is 20-40℃; and / or the pH value is 8.5-9.

8.

9. The method according to claim 5, wherein, In step (3), The second slurry has a solids content of 5-40 wt%; and / or Molding is performed by spray or compression molding; and / or The calcination is carried out in an air atmosphere, and the calcination conditions include: Temperature: 550-900℃; and / or time: 4-18 hours; and / or In step (4), the volume ratio of H2 to water vapor in the mixed atmosphere is 1:2-1:20; and / or the contact conditions include a temperature of 300-500℃; and / or a time of 2-6 hours.

10. The method according to claim 9, wherein, In step (3), the calcination conditions include: Temperatures of 620-750℃; and / or In step (4), the volume ratio of H2 to water vapor in the mixed atmosphere is 1:5-1:10; and / or the contact conditions include a temperature of 350-420℃.

11. The use of a catalyst according to any one of claims 1-4 in the oxidative dehydrogenation of low-carbon hydrocarbons.

12. The application of a catalyst according to any one of claims 1-4 in the oxidative dehydrogenation process of low-carbon monoolefins.

13. A method for the oxidative dehydrogenation of butene to produce butadiene, characterized in that, The method includes: The butene, diluent, oxidant and catalyst are reacted in contact; the catalyst includes the catalyst according to any one of claims 1-4.

14. The method according to claim 13, wherein, The conditions for the contact reaction include: a temperature of 320-560°C; and / or a volume hourly space velocity (HSV) of 300-800 h⁻¹ for butene. -1 ; and / or pressure 0.01-0.8 MPa; and / or The molar ratio of diluent to butene is 2-16; and / or The molar ratio of oxidant to butene is 0.4-1.

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