A zinc-based propane dehydrogenation catalyst for producing propylene and a preparation method thereof

Abstract

The present invention relates to a zinc-based propane dehydrogenation catalyst for preparing propylene and a preparation method thereof, and relates to the field of petrochemical catalytic technology. Based on the total dry weight of the zinc-based propane dehydrogenation catalyst for preparing propylene, the zinc-based propane dehydrogenation catalyst for preparing propylene comprises the following components: 3% to 30% by weight of zinc element, 1% to 10% by weight of auxiliary element, and the rest being a carrier; the carrier is a magnesium aluminum spinel carrier, and the auxiliary element comprises at least one of titanium, tungsten, zirconium, and tin. The present invention uses magnesium aluminum spinel as a carrier, titanium, tungsten, zirconium, and tin as auxiliary agents, and regulates the existence state of active zinc species on the surface of the carrier, so that the catalyst has better propane dehydrogenation reaction activity and selectivity, and solves the problems of expensive price and environmental pollution of the current dehydrogenation catalyst.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical catalysis, and in particular to a zinc-based propane dehydrogenation catalyst for preparing propylene and a preparation method thereof. Background Art

[0002] Propylene is an essential platform chemical for the production of polypropylene and other important industrial chemicals, and is mainly produced as a byproduct of naphtha steam or thermal cracking. With the increasing production of propane from shale gas, the direct dehydrogenation of propane to propylene has attracted attention as a promising process route for the targeted production of propylene. The PDH (C3H8C3H6+H2) reaction is highly endothermic and thermodynamically limited, so high temperatures (>550°C) are usually required. However, at such high reaction temperatures, cracking or hydrogenation of the CC bonds reduces propylene selectivity and produces coke. Therefore, practical PDH catalysts must be selective for large amounts of propane conversion, structurally stable during operation, and recyclable during regeneration cycles.

[0003] Using Al2O3 as carrier, loaded Pt-Sn and CrO x The catalyst has been used in commercial PDH process due to its high selectivity for CH and activation of CC bonds and long life. However, the high cost of precious metal platinum and Cr 6+ The environmental toxicity of species has driven the development of alternative catalysts for PDH.

[0004] Chinese patent (CN115475651A) provides a non-precious metal catalyst without Cr, with molecular sieve as carrier, and the conversion rate is low at 23% at a reaction temperature of 550°C, which cannot be used for industrial application. Chinese patent (CN112619686A) also uses zinc species as active component, molecular sieve as carrier, P or P oxide as auxiliary agent, and regulates the active component. Also at 550°C, the propane conversion rate is only 25%. Summary of the invention

[0005] In order to solve the above-mentioned problems such as poor initial activity of the propane dehydrogenation to propylene catalyst, the present invention provides a zinc-based propane dehydrogenation to propylene catalyst and a preparation method thereof.

[0006] In a first aspect, the present invention provides a zinc-based propane dehydrogenation to propylene catalyst, based on the total dry mass of the zinc-based propane dehydrogenation to propylene catalyst, the zinc-based propane dehydrogenation to propylene catalyst comprises the following components:

[0007] The weight percentage of zinc element is 3% to 30%, the weight percentage of auxiliary element is 1% to 10%, and the rest is carrier;

[0008] The carrier is a magnesium aluminum spinel carrier, and the auxiliary element includes at least one of titanium, tungsten, zirconium and tin.

[0009] Further, based on the total dry mass of the zinc-based propane dehydrogenation to propylene catalyst, the zinc-based propane dehydrogenation to propylene catalyst comprises the following components:

[0010] The mass percentage of the zinc element is 3% to 30%, the mass percentage of the auxiliary element is 1% to 10%, and the rest is a carrier.

[0011] Furthermore, the physical and chemical properties of the zinc-based propane dehydrogenation catalyst for propylene include: a specific surface area of ​​30 to 200 m 2 / g, and the pore volume is 0.15~0.9cc / g.

[0012] Furthermore, the magnesium-aluminum spinel carrier is a strip-shaped magnesium-aluminum spinel carrier; and the preparation method of the magnesium-aluminum spinel carrier comprises the following process:

[0013] Dissolve magnesium salt and aluminum salt in water to obtain solution A;

[0014] Adding a precipitant dropwise to the solution A and adjusting the pH to 4-10 to obtain a mixture B;

[0015] The mixture B is filtered and washed to obtain a filter cake C;

[0016] The filter cake C is subjected to a first calcination to obtain magnesium-aluminum spinel;

[0017] The magnesium aluminum spinel and the binder are kneaded, and then extruded and calcined to obtain a magnesium aluminum spinel carrier;

[0018] The molar ratio of the magnesium salt, the aluminum salt and the precipitant is 1:2:5, and the weight ratio of the magnesium-aluminum spinel and the binder is 1:(0.01-1):0.05.

[0019] Furthermore, the aluminum salt is at least one of aluminum chloride, nitric acid, and aluminum sulfate; the magnesium salt is at least one of magnesium nitrate, magnesium chloride, and magnesium acetate; the precipitant is one or more of ammonia water, sodium hydroxide, potassium hydroxide, sodium carbonate, and urea; and the binder is at least one of nitric acid, hydrochloric acid, acetic acid, citric acid, methyl cellulose, sesbania powder, cyclodextrin, and starch.

[0020] Furthermore, the working condition parameters of the first roasting include: temperature of 400-1200° C., and time of 1 to 6 hours; the working condition parameters of the second roasting include: temperature of 400-1200° C., and time of 1 to 6 hours.

[0021] In a second aspect, the present invention provides a method for preparing the zinc-based propane dehydrogenation catalyst for propylene as described in any one of the first aspects, the preparation method comprising the following steps:

[0022] The magnesium aluminum spinel support is allowed to stand under negative pressure;

[0023] preparing an impregnation solution containing zinc element and auxiliary element;

[0024] The impregnation liquid is absorbed onto the surface of the magnesium aluminum spinel carrier under negative pressure, and then aged, dried and thirdly calcined to obtain the zinc-based propane dehydrogenation catalyst for propylene.

[0025] Furthermore, the zinc element is derived from at least one of zinc nitrate, zinc carbonate, metallic zinc, zinc oxide, and zinc halide; the auxiliary element is derived from at least one of nitrate, chloride, oxide, and oxalate of the auxiliary element; the working condition parameters of the third roasting include: temperature of 300-600°C, time of 1-6 hours; the working condition parameters of the aging and drying include: temperature of 25-120°C, time of 1-12 hours.

[0026] In a third aspect, the present invention provides an application of the zinc-based propane dehydrogenation catalyst for preparing propylene as described in any one of the first item of the first aspect and the second aspect in the preparation of propylene by dehydrogenation of propane, wherein the working condition parameters for the preparation of propylene by dehydrogenation of propane include: a reaction pressure of 0.01 to 0.5 MPa, a temperature of 530° C. to 660° C., and a mass space velocity of 0.1 to 10 h -1 .

[0027] Furthermore, the device for preparing propylene by dehydrogenating propane adopts a fixed bed reactor.

[0028] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art:

[0029] The embodiment of the present invention provides a zinc-based propane dehydrogenation catalyst for producing propylene and a preparation method thereof. The present invention uses magnesium aluminum spinel as a carrier, titanium, tungsten, zirconium, and tin as additives, and regulates the presence state of active zinc species on the carrier surface, so that the catalyst has better propane dehydrogenation reaction activity and selectivity, and solves the problems of high price and environmental pollution of current dehydrogenation catalysts. Specifically:

[0030] The zinc-based propane dehydrogenation catalyst provided by the present invention does not contain Cr elements, has less harm to human body and environment, and does not contain precious metal elements, thereby reducing the production cost of the catalyst. The catalyst uses magnesium aluminum spinel as a carrier, and not only has good high-temperature thermal stability, but also solves the problem of carbon deposition caused by excessive acidity of traditional alumina carriers. At the same time, by introducing auxiliary elements, not only the existence state of the active components on the carrier is adjusted, so that the active components are highly dispersed on the carrier surface, but also the effect of transferring carbon deposits from active sites to the carrier surface during the dehydrogenation reaction is achieved. Based on these two advantages, the catalyst has higher propane dehydrogenation reaction performance and long-term stability. The catalyst is applied to the propane dehydrogenation reaction process, and has higher propylene selectivity and good stability. In addition, the catalyst preparation method disclosed in the present invention is simple, the raw materials are easily available, the price is low, it is non-toxic, and it has industrialization potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0033] Figure 1 A schematic flow chart of a method for preparing a zinc-based propane dehydrogenation catalyst for propylene provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0036] In a first aspect, the present invention provides a zinc-based propane dehydrogenation to propylene catalyst, based on the total dry mass of the zinc-based propane dehydrogenation to propylene catalyst, the zinc-based propane dehydrogenation to propylene catalyst comprises the following components:

[0037] The weight percentage of zinc element is 3% to 30%, the weight percentage of auxiliary element is 1% to 10%, and the rest is carrier;

[0038] The carrier is a magnesium aluminum spinel carrier, and the auxiliary element includes at least one of titanium, tungsten, zirconium and tin.

[0039] The embodiment of the present invention provides a zinc-based propane dehydrogenation catalyst for producing propylene. The present invention uses magnesium aluminum spinel as a carrier and titanium, tungsten, zirconium and tin as additives to regulate the presence state of active zinc species on the carrier surface, so that the catalyst has better propane dehydrogenation reaction activity and selectivity, thereby solving the problems of high price and environmental pollution of current dehydrogenation catalysts.

[0040] In some specific embodiments, based on the total dry weight of the zinc-based propane dehydrogenation to propylene catalyst, the zinc-based propane dehydrogenation to propylene catalyst comprises the following components:

[0041] The mass percentage of the zinc element is 3-30%, the mass percentage of the auxiliary element is 1-10%, and the rest is the carrier.

[0042] In some specific embodiments, the physicochemical properties of the zinc-based propane dehydrogenation catalyst for propylene include: a specific surface area of ​​30 to 200 m 2 / g, and the pore volume is 0.15~0.9cc / g.

[0043] In some specific embodiments, the magnesium aluminum spinel carrier is a strip-shaped magnesium aluminum spinel carrier; and the preparation method of the magnesium aluminum spinel carrier comprises the following process:

[0044] Dissolve magnesium salt and aluminum salt in water to obtain solution A;

[0045] Adding a precipitant dropwise to the solution A and adjusting the pH to 4-10 to obtain a mixture B;

[0046] The mixture B is filtered and washed to obtain a filter cake C;

[0047] The filter cake C is subjected to a first calcination to obtain magnesium-aluminum spinel;

[0048] The magnesium aluminum spinel and the binder are kneaded, and then extruded and calcined to obtain a magnesium aluminum spinel carrier;

[0049] The molar ratio of the magnesium salt, the aluminum salt and the precipitant is 1:2:5, and the weight ratio of the magnesium-aluminum spinel and the binder is 1:(0.01-1):0.05.

[0050] In some specific embodiments, the aluminum salt is at least one of aluminum chloride, aluminum nitrate, and aluminum sulfate; the magnesium salt is at least one of magnesium nitrate, magnesium chloride, and magnesium acetate; the precipitant is one or more of ammonia water, sodium hydroxide, potassium hydroxide, sodium carbonate, and urea; and the binder is at least one of nitric acid, hydrochloric acid, acetic acid, citric acid, methyl cellulose, sesbania powder, cyclodextrin, and starch.

[0051] In some specific embodiments, the working condition parameters of the first calcination include: temperature of 400-1200° C., and time of 1 to 6 hours; the working condition parameters of the second calcination include: temperature of 400-1200° C., and time of 1 to 6 hours.

[0052] In a second aspect, the present invention provides a method for preparing the zinc-based propane dehydrogenation catalyst for propylene as described in any one of the first aspects, such as Figure 1 As shown, the preparation method comprises the following steps:

[0053] The magnesium aluminum spinel support is allowed to stand under negative pressure;

[0054] preparing an impregnation solution containing zinc element and auxiliary element;

[0055] The impregnation liquid is absorbed onto the surface of the magnesium aluminum spinel carrier under negative pressure, and then aged, dried and thirdly calcined to obtain the zinc-based propane dehydrogenation catalyst for propylene.

[0056] In some specific embodiments, the zinc element is derived from at least one of zinc nitrate, zinc carbonate, metallic zinc, zinc oxide, and zinc halide; the auxiliary element is derived from at least one of nitrate, chloride, oxide, and oxalate of the auxiliary element; the working condition parameters of the third roasting include: 300-600°C, time is 1-6 hours; the working condition parameters of the aging and drying include: temperature is 25-120°C, time is 1-12 hours.

[0057] In the third aspect, based on the same inventive concept, the present invention provides the use of the zinc-based propane dehydrogenation to propylene catalyst described in any one of the first and second aspects of the first aspect in the preparation of propylene by dehydrogenation of propane, wherein the working condition parameters of the propane dehydrogenation to propylene include: reaction pressure of 0.01 to 0.5 MPa, temperature of 530°C to 660°C, mass space velocity of 0.1 to 10 h -1 .

[0058] In some specific embodiments, the device for preparing propylene by dehydrogenating propane adopts a fixed bed reactor.

[0059] It should be noted that the component raw materials involved in the zinc-based propane dehydrogenation to propylene catalyst and the preparation method thereof provided in the embodiments of the present invention, unless otherwise specified or specifically described, can be directly commercially available products or homemade using existing public preparation methods; at the same time, the steps and parameters involved, unless otherwise specified or specifically described, can be carried out according to the existing processing technology of zinc-based propane dehydrogenation to propylene catalyst or directly using existing equipment, and the present invention document will not repeat them one by one.

[0060] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0061] Example 1

[0062] This embodiment provides a magnesium aluminum spinel carrier, and the preparation and molding method thereof includes:

[0063] 95 g of magnesium chloride and 754 g of aluminum nitrate were weighed and dissolved in 1 L of deionized water, and ultrasonically dissolved. 150 g of a certain amount of urea was weighed and poured into the above-mentioned mixed solution, and stirred at high speed for 2 hours. Then, the water bath was heated to 80°C to decompose the urea and precipitate it completely, and then it was allowed to stand and age for 8 hours. The aged product was filtered and washed, and the filter cake was dried in an oven at 80°C and calcined in a muffle furnace at 1000°C for 6 hours to obtain a MgAl2O4 carrier. The obtained MgAl2O4 carrier was put into a kneader, 7.32 g of sesbania powder, 36.6 g of nitric acid solution and 60 g of deionized water were weighed and poured into the kneader, and after kneading for 18 minutes, it was extruded and formed. The extruded carrier was dried in an oven at 100°C and calcined at 800°C for 4 hours to obtain a strip-shaped MgAl2O4 carrier.

[0064] This embodiment also provides a propane dehydrogenation catalyst, the preparation method of which includes:

[0065] The prepared strip-shaped magnesium aluminum spinel carrier was placed under negative pressure for 30 minutes. Zinc acetate was used as a zinc precursor, and an impregnation solution containing 10% Zn by mass was prepared. The impregnation solution was sucked into the carrier surface under negative pressure, aged and dried for 12 hours, and then calcined in a muffle furnace at 600°C for 6 hours to obtain a catalyst 10Zn / MgAl2O4.

[0066] Example 2

[0067] This embodiment provides a magnesium aluminum spinel carrier, and the preparation and molding method thereof includes:

[0068] Weigh 128g magnesium nitrate (0.5mol) and 133g aluminum chloride and dissolve them in 500ml deionized water for ultrasonic dissolution. Weigh 140g pure ammonia and pour it into the above mixed solution, stir it at high speed for 2h, and then let it stand for 8 hours. Filter and wash the aged product, dry the filter cake in an oven at 80℃, and roast it in a muffle furnace at 1000℃ for 6 hours to obtain the MgAl2O4 carrier. Put the obtained MgAl2O4 carrier into a kneader, weigh 21.3g methyl cellulose, 14.2g nitric acid solution and deionized water into the kneader, knead for 18 minutes, and then extrude it. Put the extruded carrier into a 100℃ oven for drying, and roast it at 800℃ for 4h to obtain a strip-shaped MgAl2O4 carrier.

[0069] This embodiment also provides a propane dehydrogenation catalyst, the preparation method of which includes:

[0070] The prepared strip-shaped magnesium aluminum spinel carrier was placed under negative pressure for 30 minutes. Zinc nitrate was used as a zinc precursor, titanium dioxide powder was used as a titanium precursor, and an impregnation solution containing 10% Zn and 3% Ti by mass was prepared. The impregnation solution was sucked into the carrier surface under negative pressure, aged and dried for 12 hours, and then calcined in a muffle furnace at 600°C for 6 hours to obtain a catalyst 10Zn-3Ti / MgAl2O4.

[0071] Example 3

[0072] This embodiment provides a magnesium aluminum spinel carrier, and the preparation and molding method thereof includes:

[0073] Weigh 128g of magnesium nitrate and 133g of aluminum chloride and dissolve them in 500ml of deionized water for ultrasonic dissolution. Weigh 160g of quantitative sodium hydroxide and pour it into the above mixed solution, stir it at high speed for 2h, and then let it stand for 8 hours. Filter and wash the aged product, dry the obtained filter cake in an oven at 80℃, and roast it in a muffle furnace at 1000℃ for 6 hours to obtain the MgAl2O4 carrier. Put the obtained MgAl2O4 carrier into a kneader, weigh 21.3g of cyclodextrin, 14.2g of nitric acid solution and deionized water into the kneader, knead for 18 minutes, and then extrude it. Put the extruded carrier into a 100℃ oven for drying, and roast it at 800℃ for 4h to obtain a strip-shaped MgAl2O4 carrier.

[0074] This embodiment also provides a propane dehydrogenation catalyst, the preparation method of which includes:

[0075] The prepared strip-shaped magnesium aluminum spinel carrier was placed under negative pressure for 30 minutes. Zinc acetate was used as a zinc precursor, zirconium oxynitrate was used as a zirconium precursor, and an impregnation solution containing 10% Zn and 3% Zr was prepared. The impregnation solution was sucked onto the carrier surface under negative pressure, aged and dried for 12 hours, and then calcined in a muffle furnace at 600°C for 6 hours, and the catalyst was 10Zn-3Zr / MgAl2O4.

[0076] Example 4

[0077] This embodiment provides a magnesium aluminum spinel carrier, and the preparation and molding method thereof includes:

[0078] Weigh 128g of magnesium nitrate and 133g of aluminum chloride and dissolve them in 500ml of deionized water for ultrasonic dissolution. Weigh 224g of quantitative potassium hydroxide and pour it into the above mixed solution, stir it at high speed for 2h, and then let it stand for aging. Filter and wash the aged product, dry the obtained filter cake in an oven at 80℃, and roast it in a muffle furnace at 1000℃ for 6 hours to obtain the MgAl2O4 carrier. Put the obtained MgAl2O4 carrier into a kneader, weigh 21.3g of starch, 14.2g of nitric acid solution and deionized water into the kneader, knead for 18 minutes, and then extrude it. Put the extruded carrier into a 100℃ oven for drying, and roast it at 800℃ for 4h to obtain a strip-shaped MgAl2O4 carrier.

[0079] This embodiment also provides a propane dehydrogenation catalyst, the preparation method of which includes:

[0080] The prepared strip-shaped magnesium aluminum spinel carrier was placed under negative pressure for 30 minutes. Zinc acetate was used as the zinc precursor, ammonium metatungstate was used as the tungsten precursor, and an impregnation solution containing 10% Zn and 3% W was prepared. The impregnation solution was sucked into the carrier surface under negative pressure, aged and dried for 12 hours, and then calcined in a muffle furnace at 600°C for 6 hours, and the catalyst was 10Zn-3W / MgAl2O4.

[0081] Example 5

[0082] This embodiment provides a magnesium aluminum spinel carrier, and the preparation and molding method thereof includes:

[0083] Weigh 128g of magnesium nitrate and 133g of aluminum chloride and dissolve them in 500ml of deionized water for ultrasonic dissolution. Weigh 224g of quantitative potassium hydroxide and pour it into the above mixed solution, stir it at high speed for 2h, and then let it stand for aging. Filter and wash the aged product, dry the obtained filter cake in an oven at 80℃, and roast it in a muffle furnace at 1000℃ for 6 hours to obtain the MgAl2O4 carrier. Put the obtained MgAl2O4 carrier into a kneader, weigh 21.3g of starch, 14.2g of nitric acid solution and deionized water into the kneader, knead for 18 minutes, and then extrude it. Put the extruded carrier into a 100℃ oven for drying, and roast it at 800℃ for 4h to obtain a strip-shaped MgAl2O4 carrier.

[0084] This embodiment also provides a propane dehydrogenation catalyst, the preparation method of which includes:

[0085] The prepared strip-shaped magnesium aluminum spinel carrier was placed under negative pressure for 30 minutes. Zinc acetate was used as the zinc precursor and stannous chloride was used as the tin precursor to prepare an impregnation solution containing 10% Zn and 3% Sn. The impregnation solution was sucked into the carrier surface under negative pressure, aged and dried for 12 hours, and then calcined in a muffle furnace at 600°C for 6 hours, and the catalyst was 10Zn-3Sn / MgAl2O4.

[0086] Comparative Example 1

[0087] This comparative example provides a propane dehydrogenation catalyst, and its preparation method comprises:

[0088] Weigh 10g of the commercially formed carrier α-alumina and disperse it in 50ml of deionized water, stir at high speed for 30min to obtain a mixed solution A. Weigh 1g of the Zn precursor solution zinc nitrate and add it to 20ml of deionized water for ultrasonic dissolution to obtain a solution B. Under the condition of high-speed stirring of the mixed solution A, add the B solution dropwise, mix evenly, stir at room temperature for 2h, and evaporate the solvent to dryness by rotary evaporation. The obtained dry product is placed in an oven at 80℃ for drying and calcined at 600℃ for 4h. The catalyst is recorded as 10Zn / Al2O3.

[0089] Comparative Example 2

[0090] This comparative example provides a propane dehydrogenation catalyst, and its preparation method comprises:

[0091] 102 g of aluminum oxide sample and 40 g of magnesium oxide were weighed and put into a kneader, and 30 g of nitric acid, 6 g of cyclodextrin and 60 g of deionized water were added and kneaded for 30 minutes, and then extruded, dried and calcined.

[0092] Weigh 10g of the formed carrier and disperse it in 50ml of deionized water, stir at high speed for 30min to obtain a mixed solution A. Weigh 1g of the Zn precursor solution zinc nitrate and add it to 20ml of deionized water for ultrasonic dissolution to obtain a solution B. Under the condition of high-speed stirring of the mixed solution A, add the B solution dropwise, mix evenly, stir at room temperature for 2h, and evaporate the solvent by rotary evaporation. The obtained dry product is placed in an oven at 80℃ for drying and calcined at 600℃ for 4h. The catalyst is recorded as 10Zn / MgO-Al2O3.

[0093] Comparative Example 3

[0094] This example provides a propane dehydrogenation catalyst and a preparation method thereof, which is different from Example 1 only in that the zinc content is 2%; the remaining steps and parameters are the same.

[0095] Comparative Example 4

[0096] This example provides a propane dehydrogenation catalyst and a preparation method thereof, which differs from Example 2 only in that the zinc content is 2% and the auxiliary element titanium content is 3%; the remaining steps and parameters are the same.

[0097] Comparative Example 5

[0098] This example provides a propane dehydrogenation catalyst and a preparation method thereof, which differs from Example 1 only in that the zinc content is 2%, the auxiliary element titanium content is 0.5%; the remaining steps and parameters are the same.

[0099] Test Case

[0100] In this example, the above propane dehydrogenation catalyst for propylene was tested for performance. The process flow adopted is the existing process flow, which will not be elaborated in detail in the embodiment. The control parameters in the process flow are as follows: propane space velocity is 1h -1 , introduce an appropriate amount of nitrogen, maintain the propane partial pressure at 50 kPa, and the total pressure of the reaction system is atmospheric pressure; the bed temperature is 550-580° C. The carrier compositions of the embodiments and comparative examples are shown in Table 1, and the catalyst compositions and propane dehydrogenation catalytic performance are shown in Table 2.

[0101] Table 1 Carrier compositions of various embodiments and comparative examples

[0102]

[0103]

[0104] Table 2 Catalyst composition and catalytic performance of propane dehydrogenation

[0105] sample Catalyst name Zn source Additives Precursor Conversion rate Selectivity Example 1 <![CDATA[10Zn / MgAl2O4]]> Zinc acetate / / 36.94 89.13 Example 2 <![CDATA[10Zn-3Ti / MgAl2O4]]> Zinc nitrate Ti Titanium Dioxide 37.46 89.29 Example 3 <![CDATA[10Zn-3Zr / MgAl2O4]]> Zinc acetate Zr Zirconium nitrate 40.86 88.49 Example 4 <![CDATA[10Zn-3W / MgAl2O4]]> Zinc nitrate W Ammonium Metatungstate 41.41 88.51 Example 5 <![CDATA[10Zn-3Sn / MgAl2O4]]> Zinc nitrate Sn Stannous chloride 41.64 89.52 Comparative Example 1 <![CDATA[10Zn / Al2O3]]> Zinc nitrate / / 27.53 85.91 Comparative Example 2 <![CDATA[10Zn / MgO-Al2O3]]> Zinc nitrate / / 31.76 88.31 Comparative Example 3 <![CDATA[2Zn / MgAl2O4]]> Zinc acetate / / 30.17 86.68 Comparative Example 4 <![CDATA[2Zn-3Ti / MgAl2O4]]> Zinc nitrate Ti Titanium Dioxide 33.71 89.34 Comparative Example 5 <![CDATA[2Zn-0.5Ti / MgAl2O4]]> Zinc nitrate Ti Titanium Dioxide 31.03 88.91

[0106] It can be seen from Table 2 that: compared with Example 1 and Comparative Example 12, the catalyst with magnesium aluminum spinel as the carrier has a significantly improved propane conversion rate in the propane dehydrogenation reaction. At the same time, the catalyst of Example 2345 obtained by adding an auxiliary agent has an improved propane conversion rate in the propane dehydrogenation reaction.

[0107] It can be found from Example 1 and Comparative Example 3, and Example 2 and Comparative Example 4 that when magnesium aluminum spinel is used as a carrier and the loading amount of active metal Zn species is increased from 2% to 10%, the propane conversion rate is greatly improved; it can be seen from the experiment of Comparative Example 45 that by increasing the loading amount of the auxiliary agent, the propane conversion rate and selectivity are improved.

[0108] Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0109] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A zinc-based propane dehydrogenation catalyst for producing propylene, characterized in that: Based on the total dry weight of the zinc-based propane dehydrogenation to propylene catalyst, the zinc-based propane dehydrogenation to propylene catalyst comprises the following components: The weight percentage of zinc element is 3% to 30%, the weight percentage of auxiliary element is 1% to 10%, and the rest is carrier; The carrier is a magnesium aluminum spinel carrier, and the auxiliary element includes at least one of titanium, tungsten, zirconium and tin.

2. The zinc-based propane dehydrogenation to propylene catalyst according to claim 1, characterized in that: Based on the total dry weight of the zinc-based propane dehydrogenation to propylene catalyst, the zinc-based propane dehydrogenation to propylene catalyst comprises the following components: The mass percentage of zinc element is 3-30%, the mass percentage of auxiliary element is 1-10%, and the rest is carrier.

3. The zinc-based propane dehydrogenation to propylene catalyst according to claim 1, characterized in that: The physical and chemical property parameters of the zinc-based propane dehydrogenation catalyst for propylene production include: a specific surface area of ​​30 to 200 m 2 / g, and the pore volume is 0.15~0.9cc / g.

4. The zinc-based propane dehydrogenation to propylene catalyst according to claim 1, characterized in that: The magnesium aluminum spinel carrier is a strip-shaped magnesium aluminum spinel carrier; the preparation method of the magnesium aluminum spinel carrier The process includes: Dissolve magnesium salt and aluminum salt in water to obtain solution A; Adding a precipitant dropwise to the solution A and adjusting the pH to 4-10 to obtain a mixture B; The mixture B is filtered and washed to obtain a filter cake C; The filter cake C is subjected to a first calcination to obtain magnesium-aluminum spinel; The magnesium aluminum spinel and the binder are kneaded, and then extruded and calcined to obtain a magnesium aluminum spinel carrier; The molar ratio of the magnesium salt, the aluminum salt and the precipitant is 1:2:5, and the weight ratio of the magnesium-aluminum spinel and the binder is 1:(0.01-1):0.

05.

5. The zinc-based propane dehydrogenation to propylene catalyst according to claim 4, characterized in that: The aluminum salt is at least one of aluminum chloride, aluminum nitrate, and aluminum sulfate; the magnesium salt is at least one of magnesium nitrate, magnesium chloride, and magnesium acetate; the precipitant is one or more of ammonia water, sodium hydroxide, potassium hydroxide, sodium carbonate, and urea; and the binder is at least one of nitric acid, hydrochloric acid, acetic acid, citric acid, methyl cellulose, sesbania powder, cyclodextrin, and starch.

6. The zinc-based propane dehydrogenation to propylene catalyst according to claim 4, characterized in that: The working condition parameters of the first roasting include: temperature of 400-1200° C., and time of 1 to 6 hours; the working condition parameters of the second roasting include: temperature of 400-1200° C., and time of 1 to 6 hours.

7. A method for preparing the zinc-based propane dehydrogenation to propylene catalyst according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: The magnesium aluminum spinel support is allowed to stand under negative pressure; preparing an impregnation solution containing zinc element and auxiliary element; The impregnation liquid is absorbed onto the surface of the magnesium aluminum spinel carrier under negative pressure, and then aged, dried and thirdly calcined to obtain the zinc-based propane dehydrogenation catalyst for propylene.

8. The method for preparing a zinc-based propane dehydrogenation catalyst to propylene according to claim 7, characterized in that: The zinc element is derived from at least one of zinc nitrate, zinc carbonate, metallic zinc, zinc oxide, and zinc halide; the auxiliary element is derived from at least one of nitrate, chloride, oxide, and oxalate of the auxiliary element; The working condition parameters of the third roasting include: temperature of 300-600° C., time of 1-6 hours; the working condition parameters of the aging and drying include: temperature of 25-120° C., time of 1-12 hours.

9. Use of the zinc-based propane dehydrogenation to propylene catalyst according to any one of claims 1 to 8 in the preparation of propylene by dehydrogenation of propane, characterized in that: The working condition parameters for preparing propylene by dehydrogenation of propane include: reaction pressure of 0.01-0.5 MPa, temperature of 530° C.-660° C., mass space velocity of 0.1-10 h -1 .

Images