Method for preparing high-performance dehydrogenation Pt-based molecular sieve catalyst by using waste catalyst and application of high-performance dehydrogenation Pt-based molecular sieve catalyst

Abstract

The invention discloses a method for preparing a high-performance dehydrogenation Pt-based molecular sieve catalyst by using a waste catalyst and application of the high-performance dehydrogenation Pt-based molecular sieve catalyst. The high-performance Pt-based molecular sieve catalyst is prepared by mixing a heteroatom molecular sieve with a Pt waste catalyst, roasting, sieving, reducing and the like. Under a high-temperature roasting condition, Pt in the waste catalyst can migrate to the heteroatom molecular sieve and is anchored at an active site of the heteroatom molecular sieve to form a high-dispersion Pt sub-nano cluster. The catalyst shows excellent propane conversion rate, propylene selectivity, long-time stability and good cyclic regeneration performance in a reaction for preparing propylene through high-temperature propane dehydrogenation. The high-performance catalyst is directly prepared from the waste catalyst, on one hand, waste of the waste catalyst and loss of precious metal are avoided, on the other hand, the recovery cost and the production cost of the waste catalyst are reduced, and a new path is developed for preparing the propane dehydrogenation catalyst.

Description

Technical Field

[0001] The present invention relates to the field of industrial catalyst preparation, and particularly to a method for preparing a high-performance dehydrogenation Pt-based molecular sieve catalyst from waste catalysts and its application. Background Art

[0002] Noble metal catalysts are widely used in many fields due to their excellent catalytic performance, especially in the fields of chemical industry, environmental protection, and electrochemistry. First, in the chemical industry, noble metal Pt catalysts are mainly used in reactions such as hydrogenation, oxidation, reduction, hydrocracking, and reforming, such as ammonia synthesis, methanol synthesis, oxidative dehydrogenation, etc. Second, Pt catalysts play a crucial role in automotive exhaust purification, effectively converting harmful gases such as carbon monoxide, nitrogen oxides, and unburned hydrocarbons into relatively harmless carbon dioxide and nitrogen. Third, Pt catalysts are commonly used as anode catalysts in fuel cells to promote the oxidation reaction of hydrogen and generate electric energy. Therefore, in the rapid development of the industrialization process, a large amount of waste Pt catalysts have been generated.

[0003] Pt in waste Pt catalysts is an expensive material, and waste Pt catalysts contain reusable Pt resources. If not effectively treated, it will lead to waste of Pt resources. However, if disposed of or treated casually or improperly, Pt is also a harmful substance, potentially harmful to the environment, which may cause Pt pollution of soil, water sources, and the atmosphere, affecting the balance of the ecosystem and posing a potential threat to human health. Therefore, how to effectively recycle and reuse the noble metals in waste catalysts has become one of the hot issues in the current catalyst research field.

[0004] Currently, the recovery of Pt from waste Pt catalysts mainly uses traditional dissolution methods, followed by purification and finally reduction to obtain metallic Pt. For example, CN108220614A discloses a method for recovering Pt metal from waste catalysts. This method adopts the traditional dissolution method to leach out all Pt through a large amount of solvents (strong acids) to achieve the purpose of recovering Pt. Although the recovery rate of Pt is improved, this method has disadvantages such as complex process, large solvent consumption, and generation of toxic and harmful gases. For example, CN113234931A discloses a method for comprehensively recovering platinum and aluminum from a failed Pt / Al 2 O 3 catalyst to recover platinum and aluminum. This method uses a large amount of sodium hydroxide solution for high-temperature and high-pressure leaching, and then solid-liquid separation to obtain a platinum-enriched slag to achieve the purpose of recovering platinum. This method realizes the efficient recovery of alumina and platinum through a complete dissolution method, but this method has disadvantages such as large consumption of alkali solvents, complex process, and large equipment site.

[0005] According to statistics, at present, the resources of precious metal Pt are in short supply. It is very necessary to recycle precious metal Pt from waste catalysts, which not only reduces resource waste but also can reduce environmental pollution. If the recycling and utilization of precious metal Pt are combined, and high-performance Pt catalysts are directly prepared from the precious metal Pt in waste catalysts, the recycling process and the re-preparation process are greatly reduced, which is an efficient recycling and utilization way for waste catalysts. In summary, combining the recycled precious metal with the existing carrier to prepare a high-performance Pt-based molecular sieve catalyst can not only realize the reuse of resources but also improve the performance of the catalyst. Summary of the Invention

[0006] The purpose of the present invention is to solve the recycling and utilization of waste catalysts, reduce resource waste and environmental pollution. The existing industrial process for recycling Pt-containing waste catalysts often uses a large amount of acid or alkali solvents to leach Pt, which has the disadvantages of complex process, releasing toxic and harmful gases, and not being able to integrate the recycling and utilization of Pt to prepare fresh Pt catalysts.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions: A high-performance dehydrogenation Pt-based molecular sieve catalyst prepared from waste catalysts, wherein the carrier of the Pt-based molecular sieve catalyst is a molecular sieve, the main metal active component is Pt, the first promoter metal is any one of Fe, Co, Ni, Cu, Zn, Ga, In, Ge, Sn, La, Ce, and the second promoter metal is any one of Group ⅠA or Group ⅡA; based on the total mass of the catalyst, the content of the molecular sieve carrier is 1.00 - 99.00 wt%, the loading of the main metal active component Pt is 0.01 - 1.00 wt%, the loading of the first promoter metal active component is 0.01 - 1.00 wt%, and the loading of the second promoter metal active component is 0.01 - 1.00 wt%.

[0008] Further, the molecular sieve is any one or a mixture of several of MWW, MFI, CHA, BEA configuration molecular sieves.

[0009] The present invention also provides a preparation method of the above high-performance dehydrogenation Pt-based molecular sieve catalyst prepared from waste catalysts, which specifically includes the following steps: (1) Dissolve the first promoter metal and the second promoter metal in deionized water to form a homogeneous solution, then impregnate it on the molecular sieve, and perform ultrasonic treatment at 30 °C for 1 h; (2) Dry and calcine the mixture obtained in step (1) to obtain a heteroatom molecular sieve, and screen it through a 20 - 40 mesh sieve; (3) Mix the heteroatom molecular sieve obtained in step (2) with the powder of Pt-containing waste catalyst evenly, and then calcine it to obtain a catalyst precursor; (4) The catalyst precursor obtained in step (3) is reduced to obtain a Pt-based molecular sieve catalyst.

[0010] Further, the first promoter metal in step (1) is any one or a mixture of several soluble salts of metals including Fe, Co, Ni, Cu, Zn, Ga, In, Ge, Sn, La, and Ce; the second promoter metal is any one or a mixture of several soluble salts of Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, and Ba.

[0011] Further, the drying temperature in step (2) is 100 - 200 °C, and the drying time is 1.00 - 20.0 h.

[0012] Further, the calcination temperature in step (2) is 100 - 1000 °C, and the calcination time is 1.00 - 100 h.

[0013] Further, the heteroatom molecular sieve in step (2) is in the shape of a strip, ingot, single column, ring, or sphere, and the size of the shape diameter is 0.10 - 10 mm.

[0014] Further, the calcination temperature in step (3) is 100 - 1000 °C, and the calcination time is 1.00 - 100 h.

[0015] Further, the reduction temperature in step (4) is 100 - 1000 °C, and the reduction time is 1.00 - 10 h.

[0016] The present invention also provides the application of the above high-performance dehydrogenation Pt-based molecular sieve catalyst in the direct dehydrogenation of propane to propylene, and its operation process is as follows: A fixed-bed reactor is used to evaluate the propane dehydrogenation performance. The Pt-based molecular sieve catalyst is loaded into the quartz tube of the reaction furnace, and precise temperature control is carried out using a three-stage thermocouple; subsequently, hydrogen is introduced for reduction pretreatment, and dehydrogenation reaction is carried out under the condition of a reduction temperature of 500 - 700 °C. The reaction gas is pure propane, and the mass space velocity of propane is 1 - 30 h -1 .

[0017] The beneficial effects of the present invention are as follows: The present invention provides a method for preparing a high-performance dehydrogenation catalyst using waste catalysts and its application. The remarkable feature of this catalyst is that it uses a Pt-containing waste catalyst as the Pt source, and by mixing it with a heteroatom-containing molecular sieve, through processes such as calcination, sieving, and reduction, a high-performance Pt-based propane dehydrogenation catalyst is obtained. The present invention mainly utilizes the very strong anchoring effect of the heteroatom-containing molecular sieve on Pt. At high temperatures, Pt in the waste catalyst will automatically migrate to the molecular sieve and be stabilized in the structure of the molecular sieve to form a high-performance propane dehydrogenation catalyst. This method not only realizes the recovery of the precious metal Pt but also realizes the efficient utilization of Pt, greatly reducing the cost of precious metal recovery and reducing the preparation cost of Pt catalysts. Most importantly, the prepared Pt-based catalyst shows excellent propane conversion, propylene selectivity, long-term stability, and good cyclic regeneration performance in the high-temperature propane dehydrogenation to propylene reaction, opening up a new path for the preparation of propane dehydrogenation catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a graph of the propane dehydrogenation catalytic performance for a long reaction time in Example 1; reaction conditions: temperature 600 °C, raw material: 100% C 3 H 8 , propane mass hourly space velocity WHSV = 6.0 h -1 .

[0019] Figure 2 It is a transmission electron microscope (HADDF-STEM) image of Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] In order to better understand the technical solution of the present invention, the following will be further described in detail with reference to specific examples and the accompanying drawings, but it does not limit the protection scope of the present invention.

[0021] The drugs used in the following examples, unless otherwise specified, are purchased through commercial channels and not treated. Among them, Pt-containing waste catalyst (Pt / Al 2 O 3 , Pt = 0.3 wt%), Pt-containing waste catalyst (PtSn / Al 2 O 3 , Pt = 0.3 wt%, Sn = 0.35 wt%), pure silica MFI molecular sieve, tin chloride (SnCl 4 ·5H 2 O), iron chloride (FeCl 3 ·3H 2 O), indium chloride (InCl 3 ·4H 2 O), zinc nitrate (Zn(NO 3 ) 2 ·6H 2O), copper chloride (CuCl 2 ·2H 2 O), potassium chloride (KCl), and sodium chloride (NaCl) were all purchased from Aladdin Reagent Co., Ltd. Deionized water used in the experiment was from the high-purity water machine in the laboratory.

[0022] Comparative Example 1 (heteroatom molecular sieve) (1) First, weigh 5.0 g of MFI support and set it aside; (2) Weigh 53.1 mg of SnCl 4 ·5H 2 O and 28.6 mg of KCl and dissolve them in 2.0 g of deionized water. After stirring for 1 h in a 30 °C water bath, a homogeneous solution is formed; (3) Slowly impregnate the homogeneous solution obtained in step (2) on the MFI support and ultrasonically treat it for 1 h at 30 °C; (4) Place the mixed sample obtained in step (3) in an oven and dry it at 120 °C for 12 h, then place it in a muffle furnace and calcine it at 600 °C for 24 h to obtain SnK / MFI (Sn = 0.35 wt%) molecular sieve.

[0023] Comparative Example 2 (heteroatom molecular sieve) (1) First, weigh 5.0 g of BEA support and set it aside; (2) Weigh 80.8 mg of (Zn(NO 3 ) 2 ·6H 2 O and 28.6 mg of KCl and dissolve them in 2.0 g of deionized water. After stirring for 1 h in a 30 °C water bath, a homogeneous solution is formed; (3) Slowly impregnate the homogeneous solution obtained in step (2) on the BEA support and ultrasonically treat it for 1 h at 30 °C; (4) Place the mixed sample obtained in step (3) in an oven and dry it at 120 °C for 12 h, then place it in a muffle furnace and calcine it at 600 °C for 24 h to obtain ZnK / BEA (Zn = 0.35 wt%) molecular sieve.

[0024] Comparative Example 3 (waste catalyst containing Pt, Pt / Al 2 O 3 , Pt = 0.3 wt%) (1) Take 5.0 g of Pt / Al 2 O 3 and place it in an oven and dry it at 100 °C for 12 h, and then place it in a muffle furnace and calcine it at 600 °C for 24 h to obtain the Pt / Al 2 O 3 catalyst precursor.

[0025] (2) Place the Pt / Al 2 O 3 catalyst precursor in a tubular furnace, and heat it to 700 °C at a heating rate of 2 °C / min under a high-purity H 2 atmosphere and keep it reduced for 5 h. Finally, obtain the Pt / Al 2 O 3 (Pt = 0.3 wt%) catalyst.

[0026] Comparative Example 4 (containing Pt waste catalyst PtSn / Al 2 O 3 , Pt = 0.3 wt%, Sn = 0.35 wt%) (1) Place 5.0 g of PtSn / Al 2 O 3 in an oven and dry it at 100 °C for 12 h, and then place it in a muffle furnace and calcine it at 600 °C for 24 h to obtain the PtSn / Al 2 O 3 catalyst precursor.

[0027] (2) Place the PtSn / Al 2 O 3 catalyst precursor in a tubular furnace, and heat it to 700 °C at a heating rate of 2 °C / min under a high-purity H 2 atmosphere and keep it reduced for 5 h. Finally, obtain the PtSn / Al 2 O 3 (Pt = 0.3 wt%, Sn = 0.35 wt%) catalyst.

[0028] Example 1 (1) First, weigh 5.0 g of MFI zeolite and set it aside; (2) Weigh 53.1 mg of SnCl 4 ·5H 2 O and 28.6 mg of KCl and dissolve them in 2.0 g of deionized water. Stir for 1 h in a 30 °C water bath to form a homogeneous solution; (3) Slowly immerse the homogeneous solution obtained in step (2) on the MFI zeolite, and ultrasonically treat it at 30 °C for 1 h; (4) Place the mixed sample obtained in step (3) in an oven and dry it at 100 °C for 12 h, then place it in a muffle furnace and calcine it at 600 °C for 24 h to obtain the SnK / MFI heteroatom zeolite, and process it into strip-shaped particles with a diameter of 0.6 mm through a forming process; (5) Mix the SnK / MFI heteroatom zeolite obtained in step (4) with the Pt-containing waste catalyst powder (Pt / Al 2 O 3(0) Mix in a mass ratio of 1:1, calcine in an air atmosphere at 800 °C for 2 hours, and sieve to obtain a fresh PtSnK / MFI catalyst precursor; (6) Place the PtSnK / MFI catalyst precursor in a tubular furnace, and under a high-purity H 2 atmosphere, raise the temperature to 700 °C at a heating rate of 2 °C / min and maintain the reduction for 5 h to finally obtain a PtSnK / MFI (Pt = 0.3 wt%, Sn = 0.35 wt%) catalyst.

[0029] Example 2 (1) First, weigh 5.0 g of MFI molecular sieve and set it aside; (2) Weigh 80.8 mg of (Zn(NO 3 ) 2 ·6H 2 O and 28.6 mg of KCl and dissolve them in 2.0 g of deionized water. After stirring in a 30 °C water bath for 1 h, a homogeneous solution is formed; (3) Slowly impregnate the homogeneous solution obtained in step (2) on the MFI molecular sieve and ultrasonically treat it at 30 °C for 1 h; (4) Place the mixed sample obtained in step (3) in an oven and dry it at 100 °C for 12 h, then place it in a muffle furnace and calcine it at 600 °C for 24 h to obtain a ZnK / MFI heteroatom molecular sieve, and process it into strip-shaped particles with a diameter of 0.6 mm through a forming process; (5) Mix the ZnK / MFI heteroatom molecular sieve obtained in step (4) with the waste Pt-containing catalyst powder (Pt / Al 2 O 3 ) in a mass ratio of 1:1, calcine in an air atmosphere at 800 °C for 2 hours, and sieve to obtain a fresh PtZnK / MFI catalyst precursor; (6) Place the PtZnK / MFI catalyst precursor in a tubular furnace, and under a high-purity H 2 atmosphere, raise the temperature to 700 °C at a heating rate of 2 °C / min and maintain the reduction for 5 h to finally obtain a PtZnK / MFI (Pt = 0.3 wt%, Zn = 0.35 wt%) catalyst.

[0030] Example 3 (1) First, weigh 5.0 g of MFI molecular sieve and set it aside; (2) Weigh 47.2 mg of CuCl 2 ·2H 2 O and 28.6 mg of KCl and dissolve them in 2.0 g of deionized water. After stirring in a 30 °C water bath for 1 h, a homogeneous solution is formed; (3) Slowly impregnate the homogeneous solution obtained in step (2) on the MFI zeolite, and perform ultrasonic treatment for 1 h at 30 °C; (4) Place the mixed sample obtained in step (3) in an oven and dry it at 100 °C for 12 h, then place it in a muffle furnace and calcine it at 600 °C for 24 h to obtain the CuK / MFI heteroatom zeolite, and process it into strip-shaped particles with a diameter of 0.6 mm through a forming process; (5) Mix the CuK / MFI heteroatom zeolite obtained in step (4) with the Pt-containing waste catalyst powder (Pt / Al 2 O 3 ) in a mass ratio of 1:1, calcine it in an air atmosphere at 800 °C for 2 h, and obtain a fresh PtCuK / MFI catalyst precursor through sieving; (6) Place the PtCuK / MFI catalyst precursor in a tubular furnace, heat it to 700 °C at a heating rate of 2 °C / min in a high-purity H 2 atmosphere and hold for reduction for 5 h, and finally obtain the PtCuK / MFI (Pt = 0.3 wt%, Cu = 0.35 wt%) catalyst.

[0031] Example 4 (1) First weigh 5.0 g of MFI zeolite and set it aside; (2) Weigh 68.6 mg of FeCl 3 ·3H 2 O and 28.6 mg of KCl and dissolve them in 2.0 g of deionized water, and stir for 1 h in a 30 °C water bath to form a homogeneous solution; (3) Slowly impregnate the homogeneous solution obtained in step (2) on the MFI zeolite, and perform ultrasonic treatment for 1 h at 30 °C; (4) Place the mixed sample obtained in step (3) in an oven and dry it at 100 °C for 12 h, then place it in a muffle furnace and calcine it at 600 °C for 24 h to obtain the FeK / MFI heteroatom zeolite, and process it into strip-shaped particles with a diameter of 0.6 mm through a forming process; (5) Mix the FeK / MFI heteroatom zeolite obtained in step (4) with the Pt-containing waste catalyst (Pt / Al 2 O 3 ) powder in a mass ratio of 1:1, calcine it in an air atmosphere at 800 °C for 2 h, and obtain a fresh PtFeK / MFI catalyst precursor through sieving; (6) Place the PtFeK / MFI catalyst precursor in a tubular furnace, heat it to 700 °C at a heating rate of 2 °C / min in a high-purity H 2 atmosphere and hold for reduction for 5 h, and finally obtain the PtFeK / MFI (Pt = 0.3 wt%, Fe = 0.35 wt%) catalyst.

[0032] Example 5 (1) First, weigh 5.0 g of MFI zeolite and set it aside; (2) Weigh 45.1 mg of InCl 3 ·4H 2 O and 28.6 mg of KCl and dissolve them in 2.0 g of deionized water. After stirring for 1 h in a 30 °C water bath, a homogeneous solution is formed; (3) Slowly immerse the homogeneous solution obtained in step (2) on the MFI zeolite and ultrasonically treat it for 1 h at 30 °C; (4) Place the mixed sample obtained in step (3) in an oven and dry it at 100 °C for 12 h, then place it in a muffle furnace and calcine it at 600 °C for 24 h to obtain InK / MFI heteroatom zeolite, and process it into strip-shaped particles with a diameter of 0.6 mm through a forming process; (5) Mix the InK / MFI heteroatom zeolite obtained in step (4) with the waste Pt-containing catalyst (Pt / Al 2 O 3 ) powder in a mass ratio of 1:1, calcine it in an air atmosphere at 800 °C for 2 h, and sieve it to obtain a fresh PtInK / MFI catalyst precursor; (6) Place the PtInK / MFI catalyst precursor in a tubular furnace, heat it to 700 °C at a heating rate of 2 °C / min in a high-purity H 2 atmosphere and hold it for reduction for 5 h, and finally obtain a PtInK / MFI (Pt = 0.3 wt%, In = 0.35 wt%) catalyst.

[0033] Example 6 (1) First, weigh 5.0 g of BEA zeolite and set it aside; (2) Weigh 53.1 mg of SnCl 4 ·5H 2 O and 28.6 mg of KCl and dissolve them in 2.0 g of deionized water. After stirring for 1 h in a 30 °C water bath, a homogeneous solution is formed; (3) Slowly immerse the solution obtained in step (2) on the BEA zeolite and ultrasonically treat it for 1 h at 30 °C; (4) Place the mixed sample obtained in step (3) in an oven and dry it at 100 °C for 12 h, then place it in a muffle furnace and calcine it at 600 °C for 24 h to obtain SnK / BEA heteroatom zeolite, and process it into strip-shaped particles with a diameter of 0.6 mm through a forming process; (5) Mix the SnK / BEA heteroatom zeolite obtained in step (4) with the waste Pt-containing catalyst powder (PtSn / Al 2 O 3(0) Mix in a mass ratio of 1:1, calcine in an air atmosphere at 800 °C for 2 hours, and obtain a fresh PtSnK / BEA catalyst precursor through sieving; (6) Place the PtSnK / MFI catalyst precursor in a tubular furnace, and under a high-purity H 2 atmosphere, raise the temperature to 700 °C at a heating rate of 2 °C / min and maintain the reduction for 5 h to finally obtain a PtSnK / BEA (Pt = 0.3 wt%, Sn = 0.35 wt%) catalyst.

[0034] Example 7 (1) First, weigh 5.0 g of BEA molecular sieve and set it aside; (2) Weigh 80.8 mg of Zn(NO 3 ) 2 ·6H 2 O and 28.6 mg of KCl and dissolve them in 2.0 g of deionized water. After stirring in a 30 °C water bath for 1 h, a homogeneous solution is formed; (3) Slowly impregnate the homogeneous solution obtained in step (2) on the BEA molecular sieve and ultrasonically treat it at 30 °C for 1 h; (4) Place the mixed sample obtained in step (3) in an oven and dry it at 100 °C for 12 h, then place it in a muffle furnace and calcine it at 600 °C for 24 h to obtain a ZnK / BEA heteroatom molecular sieve, and process it into strip-shaped particles with a diameter of 0.6 mm through a forming process; (5) Mix the ZnK / BEA heteroatom molecular sieve obtained in step (4) with the waste Pt-containing catalyst powder (PtSn / Al 2 O 3 ) in a mass ratio of 1:1, calcine in an air atmosphere at 800 °C for 2 hours, and obtain a fresh PtZnK / BEA catalyst precursor through sieving; (6) Place the PtZnK / BEA catalyst precursor in a tubular furnace, and under a high-purity H 2 atmosphere, raise the temperature to 700 °C at a heating rate of 2 °C / min and maintain the reduction for 5 h to finally obtain a PtZnK / BEA (Pt = 0.3 wt%, Zn = 0.35 wt%) catalyst.

[0035] Example 8 (1) First, weigh 5.0 g of BEA molecular sieve and set it aside; (2) Weigh 47.2 mg of CuCl 2 ·2H 2 O and 28.6 mg of KCl and dissolve them in 2.0 g of deionized water. After stirring in a 30 °C water bath for 1 h, a homogeneous solution is formed; (3) Slowly impregnate the solution obtained in step (2) on BEA zeolite, and perform ultrasonic treatment for 1 h at 30 °C; (4) Place the mixed sample obtained in step (3) in an oven and dry it at 100 °C for 12 h, then place it in a muffle furnace and calcine it at 600 °C for 24 h to obtain CuK / BEA heteroatom zeolite, and process it into strip-shaped particles with a diameter of 0.6 mm through a forming process; (5) Mix the CuK / BEA heteroatom zeolite obtained in step (4) with the Pt-containing waste catalyst powder (PtSn / Al 2 O 3 ) in a mass ratio of 1:1, calcine it in an air atmosphere at 800 °C for 2 h, and sieve it to obtain a fresh PtCuK / BEA catalyst precursor; (6) Place the PtCuK / BEA catalyst precursor in a tubular furnace, heat it to 700 °C at a heating rate of 2 °C / min in a high-purity H 2 atmosphere and maintain the reduction for 5 h, and finally obtain a PtCuK / BEA (Pt = 0.3 wt%, Cu = 0.35 wt%) catalyst.

[0036] Example 9 (1) First, weigh 5.0 g of BEA zeolite and set it aside; (2) Weigh 68.6 mg of FeCl 3 ·3H 2 O and 28.6 mg of KCl and dissolve them in 2.0 g of deionized water, and stir for 1 h in a 30 °C water bath to form a homogeneous solution; (3) Slowly impregnate the solution obtained in step (2) on the BEA support, and perform ultrasonic treatment for 1 h at 30 °C; (4) Place the mixed sample obtained in step (3) in an oven and dry it at 100 °C for 12 h, then place it in a muffle furnace and calcine it at 600 °C for 24 h to obtain FeK / BEA heteroatom zeolite, and process it into strip-shaped particles with a diameter of 0.6 mm through a forming process; (5) Mix the FeK / BEA heteroatom zeolite obtained in step (4) with the Pt-containing waste catalyst (PtSn / Al 2 O 3 ) powder in a mass ratio of 1:1, calcine it in an air atmosphere at 800 °C for 2 h, and sieve it to obtain a fresh PtFeK / BEA catalyst precursor; (6) Place the PtFeK / MFI catalyst precursor in a tubular furnace, heat it to 700 °C at a heating rate of 2 °C / min in a high-purity H 2 atmosphere and maintain the reduction for 5 h, and finally obtain a PtFeK / BEA (Pt = 0.3 wt%, Fe = 0.35 wt%) catalyst.

[0037] Example 10 (1) First, weigh 5.0 g of BEA zeolite and set it aside; (2) Weigh 45.1 mg of InCl 3 ·4H 2 O and 28.6 mg of KCl and dissolve them in 2.0 g of deionized water. Stir for 1 h in a water bath at 30 °C to form a homogeneous solution; (3) Slowly immerse the homogeneous solution obtained in step (2) on the BEA zeolite and ultrasonically treat it at 30 °C for 1 h; (4) Place the mixed sample obtained in step (3) in an oven and dry it at 100 °C for 12 h, then place it in a muffle furnace and calcine it at 600 °C for 24 h to obtain InK / BEA heteroatom zeolite, and process it into strip-shaped particles with a diameter of 0.6 mm through a forming process; (5) Mix the InK / BEA heteroatom zeolite obtained in step (4) with the Pt-containing waste catalyst (PtSn / Al 2 O 3 ) powder in a mass ratio of 1:1, calcine it in an air atmosphere at 800 °C for 2 h, and sieve it to obtain a fresh PtInK / BEA catalyst precursor; (6) Place the PtInK / BEA catalyst precursor in a tubular furnace, heat it to 700 °C at a heating rate of 2 °C / min in a high-purity H 2 atmosphere and keep it reduced for 5 h, and finally obtain a PtInK / BEA (Pt = 0.3 wt%, In = 0.35 wt%) catalyst.

[0038] The cyclic regeneration performance of the Pt-based catalysts in the examples and comparative examples is shown in Table 1.

[0039] Table 1 Comparison of the cyclic regeneration performance of different Pt-based catalysts (regenerated once every 12 h interval)

[0040] Note: Reaction conditions: temperature 600 °C, raw material: 100% C 3 H 8 , propane mass hourly space velocity WHSV = 6.0 h -1 ; regeneration conditions: calcine in an air atmosphere of 20 mL / min at 600 °C for 2 h.

[0041] As can be seen from the catalytic performance results in Table 1, the initial propane conversion and cyclic regeneration performance of the freshly prepared Pt-based molecular sieve catalysts in Examples 1-10 are significantly improved compared with those of the catalysts in Comparative Examples 1-4. Moreover, the catalysts maintain excellent propane conversion and propylene selectivity under high-temperature conditions, and the degree of catalyst deactivation is relatively small. Taking pure heteroatom molecular sieve and Pt-containing waste catalyst as examples, under the condition of pure propane at 600 °C, the initial propane conversion of the pure heteroatom molecular sieve is about 1.5%, and it has almost no catalytic performance, indicating that the heteroatom molecular sieve has no catalytic performance for propane dehydrogenation; the initial propane conversion of the pure Pt-containing waste catalyst is about 10.4%, indicating that the Pt particles in the waste catalyst have agglomerated and have almost no catalytic performance. However, after mixing and calcining the heteroatom molecular sieve and the Pt-containing waste catalyst, when reacting under the condition of pure propane at 600 °C, its initial propane conversion is about 48.2%, and it can be recycled multiple times, far superior to the reported Pt-based catalysts for propane dehydrogenation. The above comparative experimental results show that a Pt-based catalyst can be prepared by mixing a heteroatom molecular sieve and a Pt-containing waste catalyst, which not only realizes the recycling of Pt in the waste catalyst, but also can prepare a high-performance Pt-based catalyst for propane dehydrogenation.

[0042] The above fully demonstrates that a high-performance Pt-based propane dehydrogenation catalyst can be directly prepared by mixing a heteroatom molecular sieve and a Pt-containing waste catalyst. Not only can the precious metal Pt be recycled with high efficiency, but also a catalyst with excellent catalytic performance can be directly prepared using the precious metal Pt. As can be seen from Figure 1 it, during the long-term reaction of 15 days of the Pt-based catalyst prepared in Example 1, good catalytic performance is still maintained, indicating that the catalyst has excellent anti-sintering performance ( Figure 1 the data above in it is the propylene selectivity, and the data below is the propane conversion). As can be seen from Figure 2 the transmission electron microscope image, the metal nanoclusters in the Pt-based catalyst are less than 1 nm, indicating that the Pt nanoclusters are in a highly dispersed state. Most importantly, when the catalyst is deactivated, its catalytic performance can be completely restored only by high-temperature air calcination treatment, providing reliable support for the continuous use of the catalyst.

[0043] The above are only the preferred embodiments of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims

1. A high-performance dehydrogenation Pt-based molecular sieve catalyst prepared using waste catalyst, characterized in that: The carrier of the Pt-based molecular sieve catalyst is a molecular sieve, the main metal active component is Pt, the first auxiliary metal is any one of Fe, Co, Ni, Cu, Zn, Ga, In, Ge, Sn, La, and Ce, and the second auxiliary metal is any one of group IA or IA; based on the total mass of the catalyst, the content of the molecular sieve carrier is 1.00-99.00 wt%, the loading amount of the main metal active component Pt is 0.01-1.00 wt%, the loading amount of the first auxiliary metal active component is 0.01-1.00 wt%, and the loading amount of the second auxiliary metal active component is 0.01-1.00 wt%.

2. The high-performance dehydrogenation Pt-based molecular sieve catalyst prepared using waste catalyst according to claim 1, characterized in that: The molecular sieve is any one of MWW, MFI, CHA and BEA molecular sieves or a mixture of several of them.

3. A method for preparing a high-performance dehydrogenation Pt-based molecular sieve catalyst using waste catalyst as claimed in claim 1, characterized in that: The specific steps include: (1) The first auxiliary metal and the second auxiliary metal were dissolved in deionized water to form a uniform solution, which was then impregnated on the molecular sieve and ultrasonically treated at 30 °C for 1 h; (2) drying and calcining the mixture obtained in step (1) to obtain a heteroatom molecular sieve, and passing it through a 20-40 mesh sieve; (3) uniformly mixing the heteroatom molecular sieve obtained in step (2) with the Pt-containing waste catalyst powder and calcining the mixture to obtain a catalyst precursor; (4) The catalyst precursor obtained in step (3) is reduced to obtain a Pt-based molecular sieve catalyst.

4. The preparation method according to claim 3, characterized in that: In step (1), the first auxiliary metal is any one or a mixture of soluble salts of Fe, Co, Ni, Cu, Zn, Ga, In, Ge, Sn, La, and Ce metals; the second auxiliary metal is any one or a mixture of soluble salts of Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, and Ra.

5. The preparation method according to claim 3, characterized in that: The drying temperature in step (2) is 100-200°C, and the drying time is 1.00-20.0 h.

6. The preparation method according to claim 3, characterized in that: The calcination temperature in step (2) is 100-1000°C, and the calcination time is 1.00-100 h.

7. The preparation method according to claim 3, characterized in that: The heteroatom molecular sieve described in step (2) is in the shape of strips, ingots, single columns, rings, or spheres, and has a diameter of 0.10 to 10 mm.

8. The preparation method according to claim 3, characterized in that: The calcination temperature in step (3) is 100-1000°C, and the calcination time is 1.00-100 h.

9. The preparation method according to claim 3, characterized in that: The reduction temperature in step (4) is 100-1000°C, and the reduction time is 1.00-10 h.

10. Use of the high-performance dehydrogenation Pt-based molecular sieve catalyst as claimed in claim 1 in direct dehydrogenation of propane to propylene.

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