A gallium-containing alloy system catalyst applied to propane oxidative dehydrogenation to prepare propylene, a preparation method thereof and a propylene preparation method

Abstract

The application discloses a gallium-containing alloy system catalyst applied to propane oxidative dehydrogenation for preparing propylene, a preparation method of the catalyst, and a propylene preparation method, and belongs to the technical field of industrial catalysis. The propane oxidative dehydrogenation catalyst comprises an active component, an additive and a carrier, the active component and the additive are loaded on the carrier, the active component is gallium dispersed in a monatomic form, the additive is at least one of platinum, palladium, cobalt, silver and indium, and the carrier is alumina. The catalyst prepared by the application can reach an olefin yield of 23.4% under a reaction condition of 490 DEG C, has excellent stability in propane oxidative dehydrogenation, and can be stably operated for 72 hours without obvious deactivation. Compared with gallium-based catalysts in the prior art, the gallium-containing alloy system catalyst prepared by the application not only effectively inhibits excessive oxidation of olefins in propane oxidative dehydrogenation, significantly improves the selectivity of olefins and the propylene yield, but also has a simple preparation process, good repeatability and a good development prospect.

Description

Technical Field

[0001] This invention relates to the field of industrial catalysis technology, specifically to a gallium-containing alloy system catalyst for the oxidative dehydrogenation of propane to propylene, its preparation method, and a method for producing propylene. Background Technology

[0002] Propylene is an important hydrocarbon chemical and a crucial chemical raw material, commonly used as an intermediate in various chemical processes to produce a wide range of end products, including plastics manufacturing, chemical production, synthetic fibers, lubricants, coatings, and other chemical products. It has broad industrial applications, and the market demand for propylene has maintained relatively stable growth. Propylene production can employ various processes, primarily including petroleum cracking, propylene synthesis, and methanol-to-propylene production. These technologies are generally characterized by complexity, high energy consumption, and significant carbon emissions, which are detrimental to environmental protection and sustainable development. Therefore, there is an urgent need for alternative technologies to increase propylene production.

[0003] In recent years, the rapid rise of the shale gas industry has created substantial profit opportunities for propane dehydrogenation to propylene. Direct dehydrogenation of propane to propylene is a reversible, strongly endothermic reaction. While a considerable single-pass yield of propylene is achieved at higher reaction temperatures, the yield remains low. Therefore, from a thermodynamic equilibrium perspective, this reaction must be carried out at high temperature and low pressure, resulting in byproducts from thermal cracking, more severe carbon deposition on the catalyst surface, and high energy consumption – all significant issues in industrial production. Oxidative dehydrogenation of propane (ODHP) has attracted widespread attention because it is an exothermic reaction, free from thermodynamic equilibrium limitations, and can be carried out in an oxidizing atmosphere, offering advantages such as no carbon deposition, fast reaction rate, low reaction temperature, lower energy consumption, and higher feedstock utilization. However, the ODHP reaction also faces challenges such as low catalyst activity and stability, unsatisfactory propylene selectivity, and excessive oxidation byproducts. Catalyst improvement and optimization are key aspects of process improvement to increase propylene yield, extend catalyst life, and reduce energy consumption.

[0004] To address these issues, gallium-based catalysts, as low-temperature, highly efficient, and stable catalysts, have attracted considerable attention from researchers. In 1998, Japanese scientist Nakagawa first reported the application of gallium-based catalysts in dehydrogenation reactions, and since then, Ga₂O₃ catalysts have garnered widespread interest (Chem. Commun., 1998, 1025-1026). Existing research has demonstrated that the activity of gallium-based catalysts depends on the coordination state and reducibility of gallium species, the properties of the support, acid-base properties, and gallium content. Compared to Ga species supported on SiO₂, Ga species supported on Al₂O₃ exhibit higher propane dehydrogenation activity, possibly due to the Al-O-Ga structure promoting CH bond activation. Another approach to improving the activity of gallium-based catalysts is to synthesize mixed oxide catalysts using other oxides. However, the activity and selectivity of gallium-based catalysts remain too low. Coke formation and gallium species sintering occur during the PDH reaction, exhibiting low stability and poor renewability. Therefore, further research and improvement of gallium-based catalysts are needed to achieve higher PDH performance. Summary of the Invention

[0005] The purpose of this invention is to provide a gallium-containing alloy catalyst for the oxidative dehydrogenation of propane to propylene, its preparation method, and the propylene production method thereof. The active component of this catalyst is gallium species dispersed in single-atom form. After doping with an auxiliary metal, it is supported on an alumina support to form a gallium-based alloy catalyst to improve catalytic performance. Compared with traditional gallium-based catalysts, the catalyst of this invention exhibits higher propylene selectivity and olefin yield, and has good application potential in the oxidative dehydrogenation of propane.

[0006] In a first aspect, the present invention provides a propane oxidative dehydrogenation catalyst, comprising an active component, an auxiliary agent, and a support, wherein the active component and the auxiliary agent are loaded on the support, the active component is gallium dispersed in single-atom form, the auxiliary agent is at least one selected from platinum, palladium, cobalt, silver, and indium, and the support is alumina.

[0007] In the above-mentioned propane oxidative dehydrogenation catalyst, the mass percentage of gallium can be 3% to 7% based on the catalyst, and the mass percentage of each auxiliary agent can be 0.5% to 3%.

[0008] In an optional embodiment of the present invention, the mass percentage of gallium is 3% based on the catalyst, and the mass percentage of each additive is 0.5% to 3%.

[0009] In a preferred embodiment of the present invention, the mass percentage of gallium is 3% based on the catalyst, and the mass percentage of each additive is 3%.

[0010] In a second aspect, the present invention provides a method for preparing the propane oxidative dehydrogenation catalyst according to any one of the above claims, comprising the following steps:

[0011] S1. Dissolve gallium nanoparticles and the metal precursor salt of the additive in water to form an impregnation solution;

[0012] S2. The carrier is immersed in the impregnation solution, stirred and mixed evenly, and then dried and calcined in sequence to obtain the propane oxidative dehydrogenation catalyst.

[0013] The above-described preparation method for gallium nanoparticles includes the following steps:

[0014] 1) The gallium precursor salt and dry 1-octadecene were mixed and stirred for the first time to obtain the first mixed system;

[0015] 2) Add di-n-octylamine to the first mixture and stir a second time to obtain the second mixture;

[0016] 3) The second mixture was heated under an inert atmosphere. After the reaction was completed, it was separated and purified to obtain the gallium nanoparticles.

[0017] In a further preferred embodiment, the gallium precursor salt is Ga2(NMe2)6;

[0018] The stirring speed for the first stirring can be 300-500 r / min, such as 500 rpm, and the time can be 50-60 minutes, such as 50 minutes;

[0019] The second stirring speed can be 500-700 r / min, such as 500 rpm, and the time can be 3-5 minutes, such as 5 minutes;

[0020] The heating temperature can be 280-290℃, such as 290℃, and the time can be 3-5 minutes, such as 3 minutes;

[0021] The inert atmosphere may specifically be a nitrogen atmosphere.

[0022] In a further preferred embodiment, the separation step includes: adding ethanol to the reaction system, centrifuging, and obtaining Ga nanoparticles. The purification step includes: redispersing the separated Ga nanoparticles in anhydrous toluene, collecting the precipitate, and repeating the purification / precipitation step 2-3 times.

[0023] In the above preparation method, the metal precursor salt of the auxiliary agent is a nitrate, sulfate, or acetate of the auxiliary agent;

[0024] The concentration of the metal precursor salt of the auxiliary agent in the impregnation solution can be 0.01 to 0.04 g / ml, specifically 0.016 g / ml;

[0025] The stirring time can be 2 to 5 hours, such as 3 hours, and the stirring speed can be 300 to 700 r / min, such as 500 r / min.

[0026] In the above preparation method, the drying temperature can be 80-100℃, such as 80℃, and the drying time can be 6-12h, such as 12h;

[0027] The roasting is carried out in an air atmosphere, and the roasting temperature can be 500-700℃, such as 500℃. The roasting time can be 1-3 hours, such as 2 hours. The heating rate during the roasting process can be 5-10℃ / min, such as 5℃ / min.

[0028] Thirdly, the present invention provides a method for producing propylene by oxidative dehydrogenation of propane, comprising the following steps:

[0029] In the presence of oxygen and dilution gas, propane undergoes oxidative dehydrogenation under the catalysis of any of the propane oxidative dehydrogenation catalysts described above to obtain propylene.

[0030] In the above-mentioned method for producing propylene by propane oxidative dehydrogenation, the propane oxidative dehydrogenation catalyst is heated to the oxidative dehydrogenation temperature under a reducing atmosphere;

[0031] The reducing atmosphere may consist of a reducing gas with a volume percentage of 1% to 10% (e.g., 10%) and the balance gas.

[0032] The balancing gas can be nitrogen or argon;

[0033] The reducing gas can be hydrogen or carbon monoxide.

[0034] In the above-mentioned method for oxidative dehydrogenation of propane to produce propylene, the volume percentage of propane in the reaction gas composed of propane, oxygen and dilution gas can be 3% to 30%, such as 4.3%.

[0035] The volume percentage of oxygen in the reaction gas composed of the propane, the oxygen, and the dilution gas can be 1.5% to 15%, such as 2.15%.

[0036] The dilution gas may be nitrogen, helium, or argon.

[0037] The reaction pressure for the oxidative dehydrogenation can be atmospheric pressure;

[0038] The temperature for the oxidative dehydrogenation can be 460–520°C, such as 490°C;

[0039] The space-time velocity of the propane oxidative dehydrogenation catalyst can be 42-60 L / g / h, such as 42 L / g / h, based on the amount of reaction gas passing through each gram of catalyst per unit time.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] (1) The preparation method of the present invention is simple, easy to operate, has low equipment requirements, and is easy to scale up for production.

[0042] (2) The gallium-containing propane oxidative dehydrogenation catalyst provided by the present invention adjusts the structure and state of gallium species by changing the type and content of the doping auxiliary metal, while greatly improving the dispersion and utilization of metal atoms. In this way, the optimal values ​​of propane conversion and propylene selectivity in the ODHP reaction can be obtained by controlling and adjusting the composition and content, and a gallium-containing alloy catalyst with optimal propylene yield can be prepared.

[0043] (3) The gallium-containing propane oxidative dehydrogenation catalyst provided by the present invention has high stability and good catalytic activity. It can reduce the reaction temperature of propane oxidative dehydrogenation and can operate stably for 72 hours without significant deactivation. Under reaction conditions of 490℃, the yield of olefins of this catalyst can reach 23.4%. It has significant technical and economic benefits and has wide application value.

[0044] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the disclosure of the present invention. Detailed Implementation

[0045] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0046] Unless otherwise specified, the methods used in the following embodiments are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.

[0047] In the quantitative experiments described below, three replicates were performed, and the data were the average of the three replicates.

[0048] In the following embodiments, the formulas for calculating conversion rate, selectivity, and yield are as follows:

[0049]

[0050]

[0051] Product yield (%) = Alkane conversion rate × Product selectivity

[0052] The formula for calculating reaction spacetime velocity is as follows:

[0053]

[0054] Comparative Example 1

[0055] The preparation method of the propane oxidative dehydrogenation catalyst provided in this embodiment specifically includes the following steps:

[0056] 1) Inject N2 into the reaction flask and heat to 290°C.

[0057] 2) 7 mL of 1-octadecene was placed in a three-necked flask and dried under vacuum at 110 °C for 60 minutes to obtain dried 1-octadecene.

[0058] 3) Mix 50 mg of gallium species precursor Ga2(NMe2)6 and 3.75 mL of the above-mentioned dried 1-octadecene at 500 rpm for 50 minutes, then add 2.25 mL of di-n-octylamine and stir for another 5 minutes. Then inject the solution into the reaction flask in 1) above and react for 3 minutes.

[0059] 4) Add 15 mL of ethanol to the solution after the above reaction, and then centrifuge at 5000 rpm for 20 minutes to initially separate the Ga nanoparticles. Then redisperse the Ga nanoparticles in anhydrous toluene, and repeat the purification / precipitation steps 2-3 times to obtain the final gallium nanoparticles.

[0060] 5) Dissolve 0.01g of the above gallium nanoparticles in 1mL of deionized water, immerse 1.0g of Al2O3 in the above solution, stir at room temperature for 3 hours, with a rotor speed of 500r / min, and then dry at 80℃ for 12h.

[0061] 6) The material obtained in step 5) is roasted in a muffle furnace with air in the roasting atmosphere, at a roasting temperature of 500°C for 2 hours, and at a heating rate of 5°C / min.

[0062] The catalyst prepared in this example has a gallium mass fraction of 1%, denoted as 1Ga / Al2O3.

[0063] 0.1 g of 1Ga / Al2O3 was placed in a fixed-bed reactor and heated to 490 °C in a 10% hydrogen atmosphere (with nitrogen as the equilibrium gas). The hydrogen gas was then turned off, and a reaction gas was introduced, consisting of 4.3% propane, 2.15% oxygen, and the remainder nitrogen, at a space-time velocity of 42 L / g / h.

[0064] The activity evaluation results of Comparative Example 1 are shown in Table 1.

[0065] Table 1. Catalytic activity of Comparative Example 1

[0066] propane conversion rate 12.2 propylene selectivity 60.3 propylene yield 7.4

[0067] Comparative Example 2

[0068] The method used in Comparative Example 1 was used for preparation, the only difference being that in step 4, 0.03 g of gallium nanoparticles were dissolved in 1 mL of deionized water, and 1.0 g of Al2O3 was immersed in the above solution.

[0069] The catalyst prepared in this comparative example has a gallium mass fraction of 3%, denoted as 3Ga / Al2O3.

[0070] The material's catalytic propane oxidative dehydrogenation test results were consistent with those of Comparative Example 1, and the dehydrogenation activity evaluation results are shown in Table 2.

[0071] Table 2. Catalytic activity of Comparative Example 2

[0072] propane conversion rate 12.8 propylene selectivity 60.2 propylene yield 7.7

[0073] Comparative Example 3

[0074] The method of Comparative Example 1 was used for preparation, the only difference being that in step 4, 0.05 g of gallium nanoparticles were dissolved in 1 mL of deionized water, and 1.0 g of Al2O3 was immersed in the above solution.

[0075] The catalyst prepared in this example has a gallium mass fraction of 5%, denoted as 5Ga / Al2O3.

[0076] The material's catalytic propane oxidative dehydrogenation test results were consistent with those of Comparative Example 1, and the dehydrogenation activity evaluation results are shown in Table 3.

[0077] Table 3. Catalytic activity of Comparative Example 3

[0078] propane conversion rate 12.5 propylene selectivity 60.2 propylene yield 7.5

[0079] Comparative Example 4

[0080] The preparation was carried out using the method of Comparative Example 1, the only difference being that in step 4, 0.07 g of gallium nanoparticles were dissolved in 1 mL of deionized water, and 1.0 g of Al2O3 was immersed in the above solution.

[0081] The catalyst prepared in this example has a gallium mass fraction of 7%, denoted as 7Ga / Al2O3.

[0082] The material's catalytic propane oxidative dehydrogenation test results were consistent with those of Comparative Example 1, and the dehydrogenation activity evaluation results are shown in Table 4.

[0083] Table 4. Catalytic activity of Comparative Example 4

[0084] propane conversion rate 11.9 propylene selectivity 60.8 propylene yield 7.2

[0085] Comparative Example 5

[0086] The method of Comparative Example 1 was used for preparation, the only difference being that in step 4, 0.1 g of gallium nanoparticles were dissolved in 1 mL of deionized water, and 1.0 g of Al2O3 was immersed in the above solution.

[0087] The catalyst prepared in this example has a gallium mass fraction of 10%, denoted as 10Ga / Al2O3.

[0088] The material's catalytic propane oxidative dehydrogenation test results were consistent with those of Comparative Example 1, and the dehydrogenation activity evaluation results are shown in Table 5.

[0089] Table 5, Catalytic activity in Example 5

[0090] propane conversion rate 11.7 propylene selectivity 61.2 propylene yield 7.1

[0091] Example 1: Preparation of propane oxidative dehydrogenation catalyst

[0092] The preparation method of the propane oxidative dehydrogenation catalyst provided in this embodiment specifically includes the following steps:

[0093] 1) Inject N2 into the reaction flask and heat to 290°C.

[0094] 2) 7 mL of 1-octadecene was placed in a three-necked flask and dried under vacuum at 110 °C for 60 minutes to obtain dried 1-octadecene.

[0095] 3) Mix 50 mg of gallium species precursor Ga2(NMe2)6 and 3.75 mL of the above-mentioned dried 1-octadecene at 500 rpm for 50 minutes, then add 2.25 mL of di-n-octylamine and stir for another 5 minutes. Then inject the solution into the reaction flask in 1) above and react for 3 minutes.

[0096] 4) Add 15 mL of ethanol to the solution after the above reaction, and then centrifuge at 5000 rpm for 20 minutes to initially separate the Ga nanoparticles. Then redisperse the Ga nanoparticles in anhydrous toluene, and repeat the purification / precipitation steps 2-3 times to obtain the final gallium nanoparticles.

[0097] 5) Dissolve 0.030g of gallium nanoparticles and 0.016g of platinum nitrate evenly in 1mL of deionized water, immerse 1.0g of Al2O3 in the above solution, stir at room temperature for 3 hours with a rotor speed of 500r / min, and then dry at 80℃ for 12h.

[0098] 6) The material obtained in step 5) is roasted in a muffle furnace with air in the roasting atmosphere, at a roasting temperature of 500°C for 2 hours, and at a heating rate of 5°C / min.

[0099] The catalyst prepared in this example has a gallium mass fraction of 3% and a platinum mass fraction of 1%, denoted as 3Ga-1Pt / Al2O3.

[0100] The material's catalytic propane oxidative dehydrogenation test results were consistent with those of Comparative Example 1, and the dehydrogenation activity evaluation results are shown in Table 6.

[0101] Table 6. Catalytic activity in Example 1

[0102] propane conversion rate 30.4 propylene selectivity 75.2 propylene yield 22.9

[0103] Example 2

[0104] The preparation was carried out using the method of Example 1, the only difference being that in step 1, 0.03 g of gallium nanoparticles and 0.022 g of palladium nitrate were uniformly dissolved in 1 mL of deionized water, and 1.0 g of Al2O3 was immersed in the above solution.

[0105] The catalyst prepared in this example has a gallium mass fraction of 3% and a palladium mass fraction of 1%, denoted as 3Ga-1Pd / Al2O3.

[0106] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the dehydrogenation activity evaluation results are shown in Table 7.

[0107] Table 7. Catalytic activity in Example 2

[0108] propane conversion rate 29.6 propylene selectivity 76.7 propylene yield 22.7

[0109] Example 3

[0110] The preparation was carried out using the method of Example 1, the only difference being that in step 1, 0.03 g of gallium nanoparticles and 0.049 g of cobalt nitrate hexahydrate were uniformly dissolved in 1 mL of deionized water, and 1.0 g of Al2O3 was immersed in the above solution.

[0111] The catalyst prepared in this example has a gallium mass fraction of 3% and a cobalt mass fraction of 1%, denoted as 3Ga-1Co / Al2O3.

[0112] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the dehydrogenation activity evaluation results are shown in Table 8.

[0113] Table 8, Catalytic Activity in Example 8

[0114] propane conversion rate 17.4 propylene selectivity 72.8 propylene yield 12.7

[0115] Example 4

[0116] The preparation was carried out using the method of Example 1, the only difference being that in step 1, 0.03 g of gallium nanoparticles and 0.016 g of silver nitrate were uniformly dissolved in 1 mL of deionized water, and 1.0 g of Al2O3 was immersed in the above solution.

[0117] The catalyst prepared in this example has a gallium mass fraction of 3% and a silver mass fraction of 1%, denoted as 3Ga-1Ag / Al2O3.

[0118] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the dehydrogenation activity evaluation results are shown in Table 9.

[0119] Table 9, Catalytic Activity in Example 4

[0120] propane conversion rate 20.7 propylene selectivity 70.6 propylene yield 14.6

[0121] Example 5

[0122] The preparation was carried out using the method of Example 1, the only difference being that in step 1, 0.03 g of gallium nanoparticles and 0.026 g of indium nitrate were uniformly dissolved in 1 mL of deionized water, and 1.0 g of Al2O3 was immersed in the above solution.

[0123] The catalyst prepared in this example has a gallium mass fraction of 3% and an indium mass fraction of 1%, denoted as 3Ga-1In / Al2O3.

[0124] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the dehydrogenation activity evaluation results are shown in Table 10.

[0125] Table 10, Catalytic Activity in Example 5

[0126]

[0127]

[0128] Example 6

[0129] The preparation was carried out using the method of Example 1, the only difference being that in step 1, 0.03 g of gallium nanoparticles and 0.016 g of platinum nitrate were uniformly dissolved in 1 mL of deionized water, and 1.0 g of Al2O3 was immersed in the above solution.

[0130] The catalyst prepared in this example has a gallium mass fraction of 3% and a platinum mass fraction of 0.1%, denoted as 3Ga-0.1Pt / Al2O3.

[0131] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the dehydrogenation activity evaluation results are shown in Table 11.

[0132] Table 11, Catalytic activity in Example 6

[0133] propane conversion rate 26.6 propylene selectivity 74.8 propylene yield 19.9

[0134] Example 7

[0135] The preparation was carried out using the method of Example 1, the only difference being that in step 1, 0.03 g of gallium nanoparticles and 0.008 g of platinum nitrate were uniformly dissolved in 1 mL of deionized water, and 1.0 g of Al2O3 was immersed in the above solution.

[0136] The catalyst prepared in this example has a gallium mass fraction of 3% and a platinum mass fraction of 0.5%, denoted as 3Ga-0.5Pt / Al2O3.

[0137] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the dehydrogenation activity evaluation results are shown in Table 12.

[0138] Table 12, Catalytic Activity in Example 7

[0139] propane conversion rate 28.7 propylene selectivity 77.6 propylene yield 23.4

[0140] Example 8

[0141] The preparation was carried out using the method of Example 1, the only difference being that in step 1, 0.03 g of gallium nanoparticles and 0.049 g of platinum nitrate were uniformly dissolved in 1 mL of deionized water, and 1.0 g of Al2O3 was immersed in the above solution.

[0142] The catalyst prepared in this example has a gallium mass fraction of 3% and a platinum mass fraction of 3%, denoted as 3Ga-3Pt / Al2O3.

[0143] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the dehydrogenation activity evaluation results are shown in Table 13.

[0144] Table 13, Catalytic Activity in Example 8

[0145]

[0146]

[0147] Example 9

[0148] The preparation was carried out using the method of Example 1, the only difference being that in step 1, 0.03 g of gallium nanoparticles and 0.082 g of platinum nitrate were uniformly dissolved in 1 mL of deionized water, and 1.0 g of Al2O3 was immersed in the above solution.

[0149] The catalyst prepared in this example has a gallium mass fraction of 3% and a platinum mass fraction of 5%, denoted as 3Ga-5Pt / Al2O3.

[0150] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the dehydrogenation activity evaluation results are shown in Table 14.

[0151] Table 14, Catalytic Activity in Example 14

[0152] propane conversion rate 29.4 propylene selectivity 75.7 propylene yield 22.3

[0153] Example 10

[0154] The preparation was carried out using the method of Example 6, the only difference being that in step 1, 0.03 g of gallium nanoparticles and 0.131 g of platinum nitrate were uniformly dissolved in 1 mL of deionized water, and 1.0 g of Al2O3 was immersed in the above solution.

[0155] The catalyst prepared in this example has a gallium mass fraction of 3% and a platinum mass fraction of 8%, denoted as 3Ga-8Pt / Al2O3.

[0156] The material catalytic propane oxidative dehydrogenation test was the same as in Example 1, and the dehydrogenation activity evaluation results are shown in Table 15.

[0157] Table 15, Catalytic Activity in Example 10

[0158] propane conversion rate 28.9 propylene selectivity 74.7 propylene yield 21.6

[0159] Example 11

[0160] The rest is the same as in Example 8, except that the reaction time is extended to 72 hours. The results of the dehydrogenation activity evaluation are shown in Table 16.

[0161] Table 16, Catalytic Activity in Example 16

[0162] propane conversion rate 30.8 29.6 propylene selectivity 75.8 74.1 propylene yield 23.4 21.9

[0163] As can be seen from the catalytic activity of Examples 1 and 1-5 above, different types of additives result in different catalytic activities of the catalyst. Platinum and palladium are preferred catalyst additives in this invention.

[0164] As can be seen from the catalytic activity of Examples 1 and 6-10 above, the catalytic activity of catalysts with different additive contents varies. When the gallium mass percentage is 3% and the additive is platinum with a mass percentage of 3%, the propylene yield reaches its highest level. Furthermore, after 72 hours of activity testing, its conversion rate and selectivity show almost no decrease, and the catalyst performance remains essentially unchanged. In summary, when the gallium mass percentage is 3% and the additive is platinum with a mass percentage of 3%, the gallium-containing alloy catalyst used for the oxidative dehydrogenation of propane to propylene exhibits the best performance.

[0165] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including modifications made using conventional techniques known in the art that depart from the scope disclosed herein.

Claims

1. A method for the oxidative dehydrogenation of propane to propylene, characterized in that, Includes the following steps: In the presence of oxygen and dilution gas, propane undergoes oxidative dehydrogenation in the presence of a propane oxidative dehydrogenation catalyst to yield propylene; The propane oxidative dehydrogenation catalyst includes an active component, an auxiliary agent, and a support. The active component and the auxiliary agent are supported on the support. The active component is gallium dispersed in single-atom form. The auxiliary agent is at least one selected from platinum, palladium, cobalt, silver, and indium. The support is alumina. The preparation method of the propane oxidative dehydrogenation catalyst includes the following steps: S1. Dissolve gallium nanoparticles and the metal precursor salt of the additive in water to form an impregnation solution; S2. The carrier is immersed in the impregnation solution, stirred and mixed evenly, and then dried and calcined in sequence to obtain the propane oxidative dehydrogenation catalyst; The method for preparing the gallium nanoparticles includes the following steps: 1) The gallium precursor salt and dry 1-octadecene were mixed and stirred for the first time to obtain the first mixed system; 2) Add di-n-octylamine to the first mixture and stir a second time to obtain the second mixture; 3) The second mixture was heated under an inert atmosphere, and after the reaction was completed, it was separated and purified to obtain the gallium nanoparticles; The gallium precursor salt is Ga2(NMe2)6.

2. The method for producing propylene by oxidative dehydrogenation of propane according to claim 1, characterized in that: Based on the catalyst, the mass percentage of gallium is 3% to 7%, and the mass percentage of each additive is 0.5% to 3%.

3. The method for producing propylene by oxidative dehydrogenation of propane according to claim 1, characterized in that: The first stirring speed is 300~500 r / min, and the time is 50~60 minutes; The second stirring is performed at a speed of 500-700 r / min for 3-5 minutes. The heating temperature is 280~290℃, and the time is 3~5 minutes.

4. The method for producing propylene by oxidative dehydrogenation of propane according to claim 1, characterized in that: The metal precursor salt of the auxiliary agent is the nitrate, sulfate or acetate of the auxiliary agent; The concentration of the metal precursor salt of the additive in the impregnation solution is 0.01~0.04 g / ml; In step S2, the stirring time is 2-5 hours and the stirring speed is 300-700 r / min.

5. The method for producing propylene by oxidative dehydrogenation of propane according to claim 1, characterized in that: In step S2, the drying temperature is 80~100℃ and the drying time is 6~12 h; The calcination is carried out in an air atmosphere at a temperature of 500-700°C for 1-3 hours, with a heating rate of 5-10°C / min.

6. The method for producing propylene by oxidative dehydrogenation of propane according to claim 1, characterized in that: The propane oxidative dehydrogenation catalyst is heated to the oxidative dehydrogenation temperature under a reducing atmosphere; The reducing atmosphere consists of a reducing gas with a volume percentage of 1% to 10% and a balance gas. The balancing gas is nitrogen or argon; The reducing gas is hydrogen or carbon monoxide.

7. The method for producing propylene by oxidative dehydrogenation of propane according to claim 1, characterized in that: The volume percentage of propane in the reaction gas composed of propane, oxygen and dilution gas is 3% to 30%. The oxygen content in the reaction gas composed of the propane, the oxygen, and the dilution gas is 1.5% to 15% by volume. The dilution gas is nitrogen, helium, or argon. The reaction pressure for the oxidative dehydrogenation is atmospheric pressure; The temperature for the oxidative dehydrogenation is 460~520℃; The space-time velocity of the propane oxidative dehydrogenation catalyst is 42-60 L / g / h, based on the amount of reaction gas passing through each gram of catalyst per unit time.

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