Dehydrogenation catalyst, preparation method and application thereof, and method for preparing butadiene by oxidative dehydrogenation of butene under low water ratio condition

Abstract

The invention relates to a dehydrogenation catalyst, a preparation method and application thereof, and a method for preparing butadiene by oxidative dehydrogenation of butylene under a low water ratio condition, and provides a dehydrogenation catalyst which comprises a spinel phase, an iron oxide crystal phase, a silicon oxide crystal phase, a nitride and a transition metal oxide, according to the invention, the surface hydroxyl density of the ferrite in the catalyst is increased by adding nitrides and other transition metal oxide auxiliaries into the ferrite with the spinel structure for the first time, and the adsorption and coverage rate of the surface of the catalyst to water molecules are improved, so that the problem that the stability of the catalyst is reduced under the condition of low water ratio is solved.

Description

Technical Field

[0001] The invention relates to a dehydrogenation catalyst, a preparation method and application thereof, and a method for preparing butadiene by oxidative dehydrogenation of butene under low water ratio conditions. Background Art

[0002] Butadiene is a basic raw material for petrochemical industry and can be copolymerized with various compounds to produce various synthetic rubbers and synthetic resins. At present, butadiene is mainly obtained through two production methods: refinery steam cracking to produce ethylene and C4 extraction and separation, and butene oxidation. Butene oxidative dehydrogenation is a process with butadiene as the target product. It can convert butene used in civilian fuel into high-value-added butadiene. This production technology is an important supplement to C4 extraction and separation technology.

[0003] Various catalytic systems, such as the Mo-Bi system, Sn-P-Li system, and Fe salt system, can be used for the oxidative dehydrogenation of butene to produce butadiene. Although the water ratio of the Mo-Bi system is as low as 6 to 8, its selectivity is low and a large amount of organic oxygen-containing by-products are produced. The Sn-P-Li system has high activity, but the operating conditions are relatively harsh, the water-to-olefin ratio is as high as 30 or more, and the energy consumption is very high. Iron-based catalysts are currently the most widely used catalysts for the oxidative dehydrogenation of butene. Their advantages are good stability and relatively few oxidation by-products, but their water-to-olefin ratio is between 12 and 16, the production process has high energy consumption, and a large amount of wastewater, resulting in high production costs.

[0004] Since the invention of the iron-based butene oxidative dehydrogenation catalyst (USP3270080), it has undergone many generations of improvements and its performance has been continuously improved. The use of foamed silicon carbide structured carriers to load ferrite catalytic active components (CN104001533B) can enhance the mass transfer and heat transfer of the oxidative dehydrogenation reaction under a water ratio of 6; CN107973690A discloses a molybdenum-bismuth system oxidative dehydrogenation catalyst that can operate under a lower water ratio; CN111054353A and CN107537530B disclose a low-water-ratio oxidative dehydrogenation catalyst of a ferrite system, which has achieved good stability. The addition of vanadium-containing heteropolyacids can promote the dehydrogenation performance of molybdenum-bismuth catalysts (CN115487868B) under a water ratio of 2-8. However, to date, the industrial butene oxidative dehydrogenation reaction process still requires the use of a large amount of steam as a medium. Summary of the invention

[0005] The purpose of the present invention is to overcome the problem of reduced stability of the existing iron oxide catalyst in the prior art during the use of butene oxidative dehydrogenation to prepare butadiene under low water ratio conditions, and to provide a dehydrogenation catalyst and a preparation method thereof. Compared with other catalysts, the catalyst has a higher surface hydroxyl content and can effectively improve the operating stability of the dehydrogenation catalyst during the use of butene oxidative dehydrogenation to prepare butadiene under low water ratio conditions.

[0006] In order to achieve the above object, the present invention provides a dehydrogenation catalyst on one hand, which includes: a spinel phase, an iron oxide crystal phase, a silicon oxide crystal phase, a nitride and a transition metal oxide.

[0007] The second aspect of the present invention provides a method for preparing the catalyst described in the present invention, which comprises: (1) co-precipitating an Fe source, an inorganic salt containing a spinel phase, a high molecular weight organic matter and an alkali source, separating the solid and the liquid, washing and dispersing them in a solvent to form a first slurry; (2) contacting a nitrogen source, a transition metal source and a silicon source in a solvent, grinding them into a colloidal solution, and forming a second slurry; (3) contacting the second slurry with the first slurry, shaping them, and calcining them.

[0008] The third aspect of the present invention provides use of the catalyst of the present invention in preparing conjugated dienes from monoolefins.

[0009] The fourth aspect of the present invention provides a method for preparing butadiene by oxidative dehydrogenation of butene suitable for low water ratio conditions. The method comprises: contacting a diluent, an oxidant, butene and a catalyst for reaction; the catalyst comprises the catalyst described in the present invention.

[0010] Through the above technical solution, the present invention has the following beneficial effects:

[0011] The invention provides a dehydrogenation catalyst, which comprises a spinel phase, an iron oxide crystal phase, a silicon oxide crystal phase, a nitride and a transition metal oxide. The catalyst surface is improved in terms of adsorption and coverage of water molecules, thereby solving the problem of reduced stability of the catalyst under low water ratio conditions. DETAILED DESCRIPTION

[0012] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0013] The invention provides a dehydrogenation catalyst, which comprises a spinel phase, an iron oxide crystal phase, a silicon oxide crystal phase, a nitride and a transition metal oxide.

[0014] The dehydrogenation catalyst of the present invention has a high surface hydroxyl density, which is beneficial to improving the stability of the iron-based oxidative dehydrogenation reaction under low water ratio conditions, and is used in the application of preparing conjugated dienes from monoolefins, especially in the application in the preparation of butadiene, and has achieved good stability.

[0015] According to a preferred embodiment of the present invention, based on 100 wt % of the catalyst, the content of the spinel phase is 40-60 wt %, preferably 43-55 wt %.

[0016] According to a preferred embodiment of the present invention, based on 100 wt % of the catalyst, the content of the iron oxide crystal phase is 5-10 wt %, preferably 6-8 wt %.

[0017] According to a preferred embodiment of the present invention, based on 100 wt % of the catalyst, the content of the silicon oxide crystalline phase is 30-50 wt %, preferably 35-45 wt %.

[0018] According to a preferred embodiment of the present invention, based on 100 wt % of the catalyst, the content of the nitride is 0.5-5 wt %, preferably 1-3 wt %.

[0019] According to a preferred embodiment of the present invention, based on 100 wt % of the catalyst, the content of the transition metal oxide is 0.1-8 wt %, preferably 2-5 wt %.

[0020] By adopting the aforementioned preferred implementation, the surface hydroxyl density of the catalyst can be further increased, and the operating stability of the catalyst under low water ratio conditions can be enhanced.

[0021] In the present invention, the nitride has a wide range of optional materials. According to a preferred embodiment of the present invention, the nitride is selected from at least one of boron nitride, zirconium nitride, chromium nitride, magnesium nitride, iron nitride and titanium nitride, preferably at least one of zirconium nitride, chromium nitride and titanium nitride. By adopting the aforementioned preferred embodiment, the density of surface hydroxyl groups can be further increased.

[0022] In the present invention, the transition metal oxide has a wide range of options. According to a preferred embodiment of the present invention, the transition metal oxide is selected from at least one of titanium dioxide, zirconium oxide and aluminum oxide, preferably titanium dioxide and / or zirconium oxide. By adopting the above preferred embodiments, the activity of the catalyst can be further improved.

[0023] In the present invention, the surface hydroxyl content of the catalyst can be selected in a wide range. According to a preferred embodiment of the present invention, the surface hydroxyl content of the catalyst is 60-500 μmol / g, preferably 100-400 μmol / g.

[0024] In the present invention, there is no special requirement for the pore volume of the catalyst. According to a preferred embodiment of the present invention, the pore volume of the catalyst is 0.2-6 mL / g, preferably 2-2.5 mL / g. By adopting the aforementioned preferred embodiment, the mass transfer and heat transfer effect of the reactants and products can be further improved and a certain mechanical strength of the catalyst particles can be ensured.

[0025] In the present invention, there is no special requirement for the average pore size of the catalyst. According to a preferred embodiment of the present invention, the average pore size of the catalyst is 1-90 nm, preferably 20-25 nm. By adopting the above preferred embodiment, the mass transfer resistance of the reactants can be further improved and a certain mechanical strength can be ensured.

[0026] In the present invention, there is no special requirement for the specific surface area of ​​the catalyst. According to a preferred embodiment of the present invention, the specific surface area of ​​the catalyst is 1-80 m 2 / g, preferably 22-28m 2 By adopting the above preferred embodiments, the activity of the catalyst can be further improved and a certain mechanical strength can be ensured.

[0027] In the present invention, there is no special requirement for the particle size of the catalyst. According to the present invention, the average particle size of the catalyst is preferably 20-160 μm, preferably 80-120 μm.

[0028] In the present invention, there is no special requirement for the spinel structure. According to a preferred embodiment of the present invention, the spinel structure satisfies the chemical formula: AFe2O4, wherein A is a divalent metal element selected from at least one of Ca, Mn, Co, Ni, Zn, Cd, Hg, Mg and Sn. In the embodiment, divalent metal Zn is used as an example, but the scope of the present invention is not limited thereto. By adopting the aforementioned preferred embodiment, the catalyst activity can be further improved.

[0029] The dehydrogenation catalysts having the aforementioned characteristics can be used in the present invention, and there are no special requirements for their preparation methods. According to the present invention, a preparation method of the dehydrogenation catalyst is provided, which comprises: (1) co-precipitating an Fe source, an inorganic salt including the inorganic salt required for forming a spinel phase, a high molecular weight organic matter and an alkali source, aging, solid-liquid separation, washing and dispersing in a solvent to form a first slurry; (2) contacting a nitrogen source, a transition metal source and a silicon source in a solvent, grinding them into a colloidal solution, and forming a second slurry; (3) contacting the second slurry with the first slurry, molding and calcining.

[0030] In step (1) of the present invention, the inorganic salts and high molecular weight organic matter required for forming the spinel phase can be first dissolved in deionized water and then co-precipitated with an alkali source. The amount of deionized water required for dissolution is not limited and can be adjusted according to experimental conditions as long as the purpose of dissolution is achieved.

[0031] In the present invention, the washing operation in step (1) is to wash the materials after solid-liquid separation with deionized water respectively, and then use deionized water to beat and disperse them into slurry for use. The amount of deionization and the number of washing times are not limited and can be adjusted according to actual operations. In the embodiment, the slurry obtained by filtering the precipitate is beaten and washed twice with 800 ml of deionized water, and then beaten and dispersed into slurry with 200 ml of deionized water for use as an exemplary description, but the scope of the present invention is not limited thereto.

[0032] In the present invention, the silicon source can be selected from a wide range of conventional silicon sources in the art. Any raw material that can provide silicon dioxide after calcination can be suitable for the present invention, such as silica gel, silica sol, organic silicon source, etc. According to a preferred embodiment of the present invention, the silicon source is silica sol, preferably the average particle size of the silica sol is 20-200nm, preferably 80-160nm, and the solid content is 30-38wt%; silica sol (38wt%), 95nm, is used as an exemplary illustration in the embodiment, but the scope of the present invention is not limited thereto. By adopting the aforementioned preferred embodiment, the hydroxyl density on the catalyst surface and the uniform distribution of the catalytic active components in the catalyst can be further increased.

[0033] According to a preferred embodiment of the present invention, the nitrogen source is selected from at least one of boron nitride, zirconium nitride, chromium nitride, magnesium nitride, iron nitride and titanium nitride, preferably at least one of chromium nitride and titanium nitride.

[0034] According to a preferred embodiment of the present invention, the transition metal source is selected from at least one of titanium dioxide, zirconium oxide and aluminum oxide, preferably titanium dioxide and / or zirconium oxide.

[0035] In the present invention, there is no special requirement for the Fe source, and it can be selected from iron salt compounds, for example.

[0036] In the present invention, there is no special requirement for the inorganic salt required to form the spinel phase. In the embodiment, Zn salt is used as an example, but the scope of the present invention is not limited thereto. By adopting the above preferred embodiments, the catalyst activity can be further improved.

[0037] In the present invention, there is no special requirement for the high molecular weight organic matter. According to a preferred embodiment of the present invention, the high molecular weight organic matter is selected from at least one of polyethylene glycol, starch, cellulose and sucrose. In the embodiment, polyethylene glycol (mass average molecular weight 40000) is used as an example, but the scope of the present invention is not limited thereto. By adopting the above preferred embodiment, the activity of the catalyst can be further improved.

[0038] In the present invention, there is no special requirement for the alkali source. According to a preferred embodiment of the present invention, the alkali source is selected from at least one of sodium carbonate, sodium hydroxide, urea, ammonia water, hydrazine and potassium hydroxide. In the embodiment, 20wt% ammonia water is used as an example, but the scope of the present invention is not limited thereto. By adopting the above preferred embodiment, the efficiency of the precipitation process can be improved and the loss of transition metals can be avoided.

[0039] In the present invention, the amount of the high molecular weight organic matter can be selected in a wide range. According to a preferred embodiment of the present invention, the amount of the high molecular weight organic matter is 0.1-20wt%, more preferably 0.5-10wt%, and more preferably 1-6wt%, based on the total mass of the inorganic salt. By adopting the above preferred embodiment, the activity of the catalyst can be further improved.

[0040] In the present invention, the mass ratio of the inorganic salt and the Fe source required for forming the spinel phase can be selected in a wide range. According to a preferred embodiment of the present invention, the mass ratio of the inorganic salt and the Fe source required for forming the spinel phase is 0.6-1.0, preferably 0.7-0.8. By adopting the above preferred embodiment, the catalyst activity can be further improved.

[0041] In the present invention, the mass ratio of the silicon source to the Fe source can be selected in a wide range. According to a preferred embodiment of the present invention, the mass ratio of the silicon source to the Fe source is 0.45-0.65. By adopting the above preferred embodiment, the catalyst activity can be further improved.

[0042] In the present invention, the mass ratio of the nitrogen source to the Fe source can be selected in a wide range. According to a preferred embodiment of the present invention, the mass ratio of the nitrogen source to the Fe source is 0.004-0.02. By adopting the above preferred embodiment, the catalyst activity can be further improved.

[0043] In the present invention, the mass ratio of the transition metal source to the Fe source can be selected in a wide range. According to a preferred embodiment of the present invention, the mass ratio of the transition metal source to the Fe source is 0.009-0.03. By adopting the above preferred embodiment, the catalyst activity can be further improved.

[0044] In the present invention, the amount of the alkali source is not limited, and it only needs to meet the pH required in the catalyst preparation process. This step is well known to those skilled in the art and will not be described in detail in the present invention.

[0045] In the present invention, there is no special requirement for the coprecipitation conditions.

[0046] According to a preferred embodiment of the present invention, the co-precipitation temperature is 10-50°C, and 25°C is used as an example in the examples, but the scope of the present invention is not limited thereto.

[0047] According to a preferred embodiment of the present invention, the pH of the co-precipitation is 8-11, preferably 8.5-9.8.

[0048] By adopting the above-mentioned preferred embodiment, the catalyst activity can be further improved.

[0049] The time of the coprecipitation described in the present invention is not limited, and those skilled in the art can select it according to actual operation, as long as the coprecipitation endpoint pH described in the present invention is reached.

[0050] By adopting the above-mentioned preferred embodiment, the catalyst activity can be further improved.

[0051] In the present invention, there are no special requirements for the contact conditions in step (2) and step (3).

[0052] According to one embodiment of the present invention, the contact temperatures in step (2) and step (3) are respectively 0-60°C.

[0053] According to a particularly preferred embodiment of the present invention, the contact temperatures in step (2) and step (3) are each 80-90°C.

[0054] According to one embodiment of the present invention, the contact time in step (2) and step (3) is 1-300 min respectively, and 4 h is used as an example in the examples, but the scope of the present invention is not limited thereto.

[0055] According to one embodiment of the present invention, the contact rotation speeds in step (2) and step (3) are respectively 10-1000 rpm, and 800 rpm is used as an example in the examples, but the scope of the present invention is not limited thereto.

[0056] By adopting the aforementioned preferred embodiment, the uniform distribution of the catalytically active components in the catalyst can be further improved.

[0057] In the present invention, there is no special requirement for the solid content of the first slurry and the solid content of the second slurry, and those skilled in the art can select them according to actual needs, and the present invention will not elaborate on them here.

[0058] In the present invention, there is no special requirement for the molding method. According to a preferred embodiment of the present invention, the molding method is selected from one of extrusion molding, press molding and spray molding.

[0059] In the present invention, there are no special requirements for the molding conditions, which are well known to those skilled in the art and can be selected according to actual operations, and the present invention will not elaborate on them here.

[0060] According to a preferred embodiment of the present invention, the calcination is carried out in an air atmosphere.

[0061] According to a preferred embodiment of the present invention, the calcination temperature is 550-750°C, preferably 620-690°C.

[0062] According to a preferred embodiment of the present invention, the roasting time is 4-12 hours, preferably 8-12 hours.

[0063] By adopting the above-mentioned preferred embodiments, the catalyst activity and selectivity can be further improved.

[0064] The present invention provides the use of the catalyst of the present invention in the preparation of monoolefins or conjugated dienes, preferably in the preparation of butadiene.

[0065] The present invention provides a method for preparing butadiene by oxidative dehydrogenation of butene under low water ratio conditions, the method comprising: contacting a diluent, an oxidant, butene and a catalyst for reaction; the catalyst is the catalyst of the present invention.

[0066] In the present invention, there is no special requirement for the diluent. According to a preferred embodiment of the present invention, the diluent is selected from one of nitrogen, argon and water vapor. In the present invention, water vapor is used as an example in the embodiments, but the present invention is not limited to this scope. By adopting the above preferred embodiments, the reaction performance and reactor temperature can be further improved.

[0067] In the present invention, there is no special requirement for the oxidant. According to a preferred embodiment of the present invention, the oxidant is selected from one of carbon dioxide, nitrogen dioxide, air and oxygen. In the present invention, oxygen is used as an example in the embodiments, but the present invention is not limited to this scope. By adopting the above preferred embodiments, the catalyst performance can be further improved.

[0068] In the present invention, there is no special requirement for the volume ratio of the diluent to butene. According to a preferred embodiment of the present invention, the volume ratio of the diluent to butene is 3-8:1. In the embodiment, the volume ratio of the diluent to butene is 5, which is illustrative, but the scope of the present invention is not limited thereto. By adopting the above preferred embodiment, the operating stability of the catalyst can be further improved.

[0069] In the present invention, there is no special requirement for the volume ratio of the oxidant to butene. According to a preferred embodiment of the present invention, the volume ratio of the oxidant to butene is 0.4-1. In the embodiment, the volume ratio of the oxidant to butene is 0.7, which is illustrative, but the scope of the present invention is not limited thereto. By adopting the above preferred embodiments, the catalyst performance can be further improved.

[0070] In the present invention, there is no special requirement for the conditions of the contact reaction.

[0071] According to a preferred embodiment of the present invention, the temperature of the contact reaction is 320-600° C., and 380° C. is used as an example in the examples, but the scope of the present invention is not limited thereto.

[0072] According to a preferred embodiment of the present invention, the pressure of the contact reaction is 0-0.4 MPa, and 0.1 MPa is used as an example in the embodiments, but the scope of the present invention is not limited thereto.

[0073] According to a preferred embodiment of the present invention, the butene volume space velocity of the contact reaction is 200-500 hours -1 In the embodiment, 400 hours -1 This is intended to be illustrative but not to limit the scope of the invention.

[0074] By adopting the aforementioned preferred embodiment, the stability of the catalyst under low water ratio operating conditions can be further improved.

[0075] The catalyst surface hydroxyl parameters were measured by LiAlH4-gas chromatography. The XRD crystal phase structure composition was measured by X-ray diffractometer.

[0076] In the present invention, the composition of the catalyst: spinel phase, iron oxide crystal phase, silicon oxide crystal phase, nitride and transition metal oxide is obtained through X-ray diffraction test, and the composition of each component is calculated by XRD.

[0077] The pore volume, average pore diameter and specific surface area of ​​the catalyst are measured by BET specific surface area detection method.

[0078] Example 1

[0079] (1) Take 279.5g of ferric nitrate (Fe(NO3)3 9H2O), 215.3g of zinc nitrate (Zn(NO3)2.6H2O) and 14.8g of polyethylene glycol (mass average molecular weight 40000) in 800ml of deionized water, and then co-precipitate with 20wt% ammonia water at room temperature (25°C) (the pH at the end of precipitation is 9). The precipitated slurry is filtered and washed twice with 800ml of deionized water, and then dispersed into a slurry with 200ml of deionized water. The slurry is allowed to stand at 25°C for 3min and then used.

[0080] (2) At 25°C, 150 g of silica sol (38 wt%, 95 nm) was diluted with 300 ml of water, and then 3.8 g of titanium nitride powder (TiN, 400 mesh) and 5.3 g of titanium dioxide powder (anatase, 400 mesh) were added. The solution was ground in a colloid mill for 4 hours to form a colloidal solution, which was then mixed with the above 200 ml of slurry, stirred at a speed of 800 rpm, and then sprayed to obtain a catalyst powder with an average particle size of 100 μm. The catalyst powder was calcined at 680°C for 8 hours in an air atmosphere to obtain a composite oxide catalyst;

[0081] The obtained sample contained 49.5wt% zinc ferrite spinel phase, 6.5wt% iron oxide phase, 38wt% silicon oxide phase, 2.5wt% titanium nitride and 3.5wt% titanium dioxide, with a pore volume of 2.3ml / g, an average pore diameter of 22nm, and a specific surface area of ​​26m 2 / g; surface hydroxyl group 263μmol / g.

[0082] (3) At a reaction temperature of 380°C, a reaction pressure of 0.1 MPa, and a volume space velocity of 400 h for butene (1-butene) -1 Under the conditions of H2O / butene volume ratio of 5 and O2 / butene volume ratio of 0.7, after 50 hours of reaction, the butene conversion rate was 72.7% and the butadiene selectivity was 92.5%; after 200 hours, the butene conversion rate was 72.2% and the butadiene selectivity was 92.0%.

[0083] Example 2

[0084] (1) Take 260.6 g of ferric nitrate (Fe(NO3)3 9H2O), 187.0 g of zinc nitrate (Zn(NO3)2.6H2O) and 3 g of polyethylene glycol (mass average molecular weight 40000) in 800 ml of deionized water, and then co-precipitate with 20 wt% ammonia water at room temperature (25°C) (the pH at the end of precipitation is 9.8). The precipitated slurry is filtered and washed twice with 800 ml of deionized water, and then dispersed into a slurry with 200 ml of deionized water for use.

[0085] (2) At 40°C, 162.0 g of silica sol (38 wt%, 95 nm) was diluted with 300 ml of water, and then 4.5 g of chromium nitride powder (CrN, 400 mesh) and 7.5 g of titanium dioxide powder (anatase, 400 mesh) were added. The mixture was ground in a colloid mill for 4 hours to form a colloidal solution, which was then mixed with the above 200 ml of the slurry, stirred at a rotation speed of 800 rpm, and then sprayed to obtain a catalyst powder with an average particle size of 120 μm. The catalyst powder was calcined at 625°C for 12 hours to obtain a composite oxide catalyst.

[0086] The obtained sample contained 43.0wt% zinc ferrite spinel phase, 8.0wt% iron oxide phase, 41wt% silicon oxide phase, 3.0wt% chromium nitride and 5.0wt% titanium dioxide, with a pore volume of 2.4ml / g, an average pore diameter of 23nm, and a specific surface area of ​​25m 2 / g; surface hydroxyl group 379μmol / g.

[0087] (3) The same evaluation conditions as those in step (3) of Example 1 were used: after 50 hours of reaction, the butene conversion rate was 76.7% and the butadiene selectivity was 94.5%; after 200 hours of reaction, the butene conversion rate was 76.3% and the butadiene selectivity was 94.6%.

[0088] Example 3

[0089] (1) Take 301.2 g of ferric nitrate (Fe(NO3)3 9H2O), 239.2 g of zinc nitrate (Zn(NO3)2.6H2O) and 8.2 g of polyethylene glycol (mass average molecular weight 40000) in 800 ml of deionized water, and then co-precipitate with 20 wt% ammonia water at room temperature (25°C) (the pH at the end of precipitation is 8.5). The precipitated slurry is filtered and washed twice with 800 ml of deionized water, and then dispersed into a slurry with 200 ml of deionized water for use.

[0090] (2) At 60°C, 142.1 g of silica sol (38 wt%, 95 nm) was diluted with 300 ml of water, and 1.5 g of titanium nitride powder (TiN, 400 mesh) and 3.0 g of zirconium dioxide powder (400 mesh) were added. The solution was ground in a colloid mill for 4 hours to form a colloidal solution, which was then mixed with the above-mentioned 200 ml slurry. The solution was stirred at a speed of 800 rpm and then sprayed to obtain a catalyst powder with an average particle size of 80 μm. The solution was calcined at 650°C for 10 hours in an air atmosphere to obtain a composite oxide catalyst.

[0091] The obtained sample contained 55.0wt% zinc ferrite spinel phase, 6.0wt% iron oxide phase, 36wt% silicon oxide phase, 1.0wt% titanium nitride and 2.0wt% titanium dioxide, with a pore volume of 2.3ml / g, an average pore diameter of 22nm, and a specific surface area of ​​24m 2 / g; surface hydroxyl group 103μmol / g.

[0092] (3) The same evaluation conditions as those in step (3) of Example 1 were used: after 50 hours of reaction, the butene conversion rate was 70.9% and the butadiene selectivity was 92.3%; after 200 hours of reaction, the butene conversion rate was 70.1% and the butadiene selectivity was 91.6%.

[0093] Example 4

[0094] All conditions are the same as those in Example 1, except that the calcination temperature in step (2) is 780° C. to obtain the composite oxide catalyst.

[0095] Pore ​​volume 2.0ml / g, average pore diameter 20nm, specific surface area 21m 2 / g; surface hydroxyl group 62μmol / g.

[0096] (3) The same evaluation conditions as step (3) in the example were used: after 50 hours of reaction, the butene conversion rate was 72.1% and the butadiene selectivity was 91.9%; after 200 hours of reaction, the butene conversion rate was 64.3% and the butadiene selectivity was 89.1%.

[0097] Example 5

[0098] All conditions are the same as in Example 1, except that:

[0099] In step (1), 257.8 g of ferric nitrate (Fe(NO3)3 9H2O), 176.6 g of zinc nitrate (Zn(NO3)2.6H2O) and 13.0 g of polyethylene glycol (mass average molecular weight 40,000) were added to 800 ml of deionized water and then co-precipitated.

[0100] In step (2), 155.5 g of silica sol (38 wt%, 95 nm) was diluted with 300 ml of water, and then 6.9 g of titanium nitride powder (TiN, 400 mesh) and 9.5 g of titanium dioxide powder (anatase, 400 mesh) were added. The mixture was ground in a colloid mill for 4 hours to form a colloidal solution, which was then mixed with the above 200 ml of slurry, stirred evenly and sprayed to obtain a catalyst powder with a certain particle size distribution. The catalyst powder was calcined at 680°C for 8 hours to obtain a composite oxide catalyst.

[0101] The obtained sample contained 40.6wt% zinc ferrite spinel phase, 9.1wt% iron oxide phase, 39.4wt% silicon oxide phase, 4.6wt% titanium nitride and 6.3wt% titanium dioxide, with a pore volume of 2.6ml / g, an average pore diameter of 27nm, and a specific surface area of ​​28m 2 / g; surface hydroxyl group 486μmol / g.

[0102] (3) The same evaluation conditions as step (3) in the example were used: after 50 hours of reaction, the butene conversion rate was 71.8% and the butadiene selectivity was 91.5%; after 200 hours, the butene conversion rate was 65.2% and the butadiene selectivity was 88.2%.

[0103] Example 6

[0104] All conditions are the same as those in Example 1, except that in step (1), 257.8 g of ferric nitrate (Fe(NO3)39H2O), 174.7 g of copper nitrate (Cu(NO3)2.3H2O) and 13.6 g of polyethylene glycol (mass average molecular weight 40,000) are dissolved in 800 ml of deionized water and then co-precipitated.

[0105] In step (2), at 25°C, 150.1 g of silica sol (38 wt%, 95 nm) was diluted with 300 ml of water, and then 3.8 g of boron nitride powder (BN, average particle size 400 mesh) and 5.3 g of alumina powder (average particle size 400 mesh) were added. The mixture was ground in a colloid mill for 4 hours to form a colloidal solution, which was then mixed with the above-mentioned 200 ml of slurry, stirred evenly, and then sprayed to obtain a catalyst powder with a certain particle size distribution. The catalyst powder was calcined at 680°C for 8 hours to obtain a composite oxide catalyst.

[0106] The obtained sample contained 49.5wt% copper ferrite spinel phase, 6.5wt% iron oxide phase, 38wt% silicon oxide phase, 2.5wt% boron nitride and 3.5wt% aluminum oxide phase, with a pore volume of 2.5ml / g, an average pore diameter of 25nm, and a specific surface area of ​​26m 2 / g; surface hydroxyl group 405μmol / g.

[0107] The same evaluation conditions as step (3) in the embodiment were used: after 50 hours of reaction, the butene conversion rate was 73.3% and the butadiene selectivity was 92.1%; after 200 hours, the butene conversion rate was 68.2% and the butadiene selectivity was 90.3%.

[0108] Example 7

[0109] According to the method of Example 3, except that the contact temperature in step (2) is 80° C., and the other conditions are different, a catalyst is obtained;

[0110] After 50 hours of reaction, the butene conversion rate was 71.9% and the butadiene selectivity was 93.6%; after 200 hours of reaction, the butene conversion rate was 71.1% and the butadiene selectivity was 92.8%.

[0111] Comparative Example 1

[0112] The catalyst was prepared according to the method of Example 1, except that silicon dioxide, titanium nitride and titanium dioxide were not added and step (2) was not performed.

[0113] Pore ​​volume 1.9ml / g, average pore diameter 19nm, specific surface area 16m 2 / g; surface hydroxyl group 19μmol / g.

[0114] The same evaluation conditions as those in step (3) of the embodiment were used: after 50 hours of reaction, the butene conversion rate was 7.3% and the butadiene selectivity was 90.3%; after 200 hours, the butene conversion rate was 61.1% and the butadiene selectivity was 86.0%.

[0115] Comparative Example 2

[0116] The catalyst was prepared according to the method of Example 1, except that titanium nitride and titanium dioxide were not added, and titanium nitride and titanium dioxide were not added in step (2).

[0117] Pore ​​volume 2.4ml / g, average pore diameter 21nm, specific surface area 22m 2 / g; surface hydroxyl group 98μmol / g.

[0118] The same evaluation conditions as step (3) in the embodiment were used: after 50 hours of reaction, the butene conversion rate was 68.5% and the butadiene selectivity was 90.6%; after 200 hours, the butene conversion rate was 61.2% and the butadiene selectivity was 88.2%.

[0119] Comparative Example 3

[0120] The catalyst was prepared according to the method of Example 1, except that no silica sol was added in step (2).

[0121] Pore ​​volume 1.8ml / g, average pore diameter 16nm, specific surface area 19m 2 / g; surface hydroxyl group 163μmol / g.

[0122] The same evaluation conditions as step (3) in the embodiment were used: after 50 hours of reaction, the butene conversion rate was 69.9% and the butadiene selectivity was 91.0%; after 200 hours, the butene conversion rate was 62.8% and the butadiene selectivity was 89.1%.

[0123] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A dehydrogenation catalyst, characterized in that The catalyst comprises: spinel phase, iron oxide crystal phase, silicon oxide crystal phase, nitride and transition metal oxide.

2. The catalyst according to claim 1, wherein Based on 100 wt% of catalyst, The content of spinel phase is 40-60wt%, preferably 43-55wt%; and / or The content of the iron oxide crystal phase is 5-10wt%, preferably 6-8wt%; and / or The content of silicon oxide crystalline phase is 30-50wt%, preferably 35-45wt%; and / or The content of nitride is 0.5-5wt%, preferably 1-3wt%; and / or The content of transition metal oxide is 0.1-8wt%, preferably 2-5wt%; and / or The nitride is selected from at least one of boron nitride, zirconium nitride, chromium nitride, magnesium nitride, iron nitride and titanium nitride, preferably at least one of zirconium nitride, chromium nitride and titanium nitride; and / or The transition metal oxide is selected from at least one of titanium dioxide, zirconium oxide and aluminum oxide, preferably titanium dioxide and / or zirconium oxide.

3. The catalyst according to claim 1 or 2, wherein The surface hydroxyl content of the catalyst is 60-500 μmol / g, preferably 100-400 μmol / g; and / or The pore volume of the catalyst is 0.2-6 mL / g, preferably 2-2.5 mL / g; and / or The average pore size of the catalyst is 1-90 nm, preferably 20-25 nm; and / or The specific surface area of ​​the catalyst is 1-80m 2 / g, preferably 22-28m 2 / g; and / or The average particle size of the catalyst is 20-160 μm, preferably 80-120 μm; and / or The spinel structure satisfies the chemical formula: AFe2O4, wherein A is selected from at least one of Ca, Mn, Co, Ni, Zn, Cd, Hg, Mg and Sn.

4. A method for preparing the catalyst according to any one of claims 1 to 3, characterized in that: The method includes: (1) co-precipitating an Fe source, an inorganic salt including a high molecular weight organic substance required for forming a spinel phase, and an alkali source, separating the solid from the liquid, washing, and dispersing the mixture in a solvent to form a first slurry; (2) contacting a nitrogen source, a transition metal source, and a silicon source in a solvent, grinding them into a colloidal solution, and forming a second slurry; (3) The second slurry is brought into contact with the first slurry, molded, and calcined.

5. The method according to claim 4, wherein: The high molecular weight organic matter is selected from at least one of polyethylene glycol, starch, cellulose and sucrose; and / or The alkaline source is selected from at least one of sodium carbonate, sodium hydroxide, urea, ammonia water, hydrazine and potassium hydroxide; and / or The silicon source is silica sol, preferably the average particle size of the silica sol is 20-200 nm, preferably 80-160 nm, and the solid content is 30-38 wt%.

6. The method according to claim 4 or 5, wherein: The nitrogen source is at least one of boron nitride, zirconium nitride, chromium nitride, magnesium nitride, iron nitride and titanium nitride, preferably at least one of zirconium nitride, chromium nitride and titanium nitride; and / or The transition metal source is at least one of titanium dioxide, zirconium oxide and aluminum oxide, preferably titanium dioxide and / or zirconium oxide; and / or The Fe source is selected from iron salt compounds; and / or Based on the total mass of the inorganic salt, The amount of the high molecular organic matter is 0.1-20wt%, more preferably 0.5-10wt%, more preferably 1-6wt%; and / or The mass ratio of the inorganic salt required for forming the spinel phase to the Fe source is 0.6-1.0, preferably 0.7-0.8; and / or The mass ratio of the silicon source to the Fe source is 0.45-0.65; and / or The mass ratio of the nitrogen source to the Fe source is 0.004-0.02; and / or The mass ratio of the transition metal source to the Fe source is 0.009-0.

03.

7. The method according to any one of claims 4 to 6, wherein: The coprecipitation conditions include: temperature of 10-50°C; and / or pH of 8-11, preferably 8.5-9.8; and / or The contact temperatures of step (2) and step (3) are each 80-90°C; and / or The molding method is selected from one of extrusion molding, compression molding and spray molding; and / or The calcination is carried out in an air atmosphere, and the calcination conditions include: The temperature is 550-750°C, preferably 620-690°C; and / or the time is 4-12 hours, preferably 8-12 hours.

8. Use of the catalyst according to claims 1-3 in the preparation of conjugated dienes from monoolefins, preferably in the preparation of butadiene.

9. A method for preparing butadiene by oxidative dehydrogenation of butene suitable for low water ratio conditions, characterized in that: The method includes: The diluent, the oxidant, the butene and the catalyst are contacted and reacted; the catalyst comprises the catalyst according to any one of claims 1 to 3.

10. The method according to claim 9, wherein: The diluent is selected from one of nitrogen, argon and water vapor; and / or The oxidant is selected from one of nitrogen dioxide, carbon dioxide, air and oxygen; and / or The volume ratio of diluent to butene is 3-8:1; and / or The volume ratio of oxidant to butene is 0.4-1; and / or The conditions of the contact reaction include: Temperature 320-600°C; and / or pressure 0-0.4MPa; and / or butene volume space velocity of 200-500 hr-1.