A metal-supported composite molecular sieve catalyst and its preparation method and application

Abstract

The present invention provides a metal-supported composite molecular sieve catalyst and a preparation method and application thereof, and relates to the technical field of catalyst preparation. The present invention improves the carrier, adopts a high temperature resistant ZSM-5 molecular sieve or SSZ-13 molecular sieve with a large specific surface area, and combines it with γ-Al 2 O 3 The composite is used as a carrier, so that the carrier has a large specific surface area, strong loading capacity, high chemical stability and adsorption capacity, so that the catalytic reaction is more complete, the loss of active components is reduced, and the stability of the catalyst is improved. The experimental results show that when the catalyst prepared by the present invention catalyzes hydrogen chloride to produce chlorine, the chlorine yield after 8 hours of reaction is 87.8-96.28%, and the chlorine yield after 1000 hours of reaction is 86.9-96.11%.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and in particular relates to a metal-loaded composite molecular sieve catalyst and a preparation method and application thereof. Background Art

[0002] With the large-scale expansion of chlorine-related products and the development of the chlor-alkali industry, the disposal and utilization of a large amount of by-product HCl has become a common problem that restricts the environment and the development of many industries. At the same time, the demand for chlorine products is increasing, and the supply and demand relationship of chlorine is becoming increasingly tense. If the by-product hydrogen chloride is converted into chlorine, it will alleviate the contradiction of the imbalance between the supply and demand of chlorine, and fundamentally eliminate the environmental pollution caused by the by-product hydrogen chloride while improving economic benefits.

[0003] At present, the method of preparing chlorine from hydrogen chloride has attracted more and more attention due to its relatively easy application and low energy consumption. The catalyst used in the catalytic oxidation method is mainly a copper-based catalyst, which has excellent activity, low cost and easy regeneration, but due to the high reaction temperature, the catalyst is easily deactivated. Therefore, many scholars have done a lot of work in its preparation method, matching of active metals, properties of carriers, reactor structure and process conditions, aiming to improve the catalyst life and reaction activity.

[0004] Chinese patent CN101125297 discloses a catalyst containing copper chloride, potassium chloride and cerium chloride treated with phosphoric acid and supported by silicon dioxide. The catalyst has a molar ratio of hydrogen chloride to oxygen of 1:1, a fixed bed reactor temperature of 400°C, a reaction pressure of 0.1 MPa, and a hydrogen chloride feed space velocity of 0.8 hr. -1 When the reaction temperature is high, the yield of the product chlorine is 80.1%. However, the active component of the copper chloride in the catalyst is easily lost at a high temperature, which affects the service life of the catalyst. Therefore, how to improve the copper-based catalyst to improve its catalytic stability, thereby increasing the raw material conversion rate and product yield has become a technical problem that needs to be solved in this field. Summary of the invention

[0005] The purpose of the present invention is to provide a metal-supported composite molecular sieve catalyst and a preparation method and application thereof. The metal-supported composite molecular sieve catalyst prepared by the preparation method provided by the present invention has high catalytic stability.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a metal-supported composite molecular sieve catalyst, comprising the following steps:

[0008] (1) mixing a molecular sieve, γ-Al2O3 and a first solvent, and then drying and first calcining in sequence to obtain a composite molecular sieve; the molecular sieve is a ZSM-5 molecular sieve or a SSZ-13 molecular sieve;

[0009] (2) mixing the divalent copper salt, the composite molecular sieve obtained in step (1) and a second solvent, and performing a first loading to obtain a molecular sieve loaded with a precursor;

[0010] (3) subjecting the molecular sieve loaded with the precursor obtained in step (2) to a second calcination to obtain a metal-loaded composite molecular sieve catalyst.

[0011] Preferably, in step (1), the mass ratio of molecular sieve to γ-Al2O3 is (1-2):1.

[0012] Preferably, in the step (1), the temperature of the first calcination is 400-450° C., and the time of the first calcination is 2-5 hours.

[0013] Preferably, the first loading in step (2) is carried out under static conditions; the static temperature is room temperature, and the static time is 10 to 15 hours.

[0014] Preferably, the temperature of the second calcination in step (3) is 400-550° C., and the time of the second calcination is 5-8 hours.

[0015] Preferably, after the second calcination is completed, the method further comprises mixing the product obtained from the second calcination, the third solvent and the metal salt, performing a second loading, and then performing a third calcination.

[0016] Preferably, the metal salt is at least one of potassium nitrate, magnesium nitrate, strontium nitrate, yttrium nitrate, molybdenum nitrate and bismuth nitrate.

[0017] Preferably, the temperature of the third calcination is 400-550° C., and the time of the third calcination is 3-5 hours.

[0018] The present invention also provides a metal-supported composite molecular sieve catalyst prepared by the preparation method described in the above technical solution.

[0019] The present invention also provides the use of the metal-supported composite molecular sieve catalyst described in the above technical solution in the catalytic oxidation of hydrogen chloride to produce chlorine.

[0020] The present invention provides a method for preparing a metal-supported composite molecular sieve catalyst, comprising the following steps: mixing a molecular sieve, γ-Al2O3 and a first solvent, and then drying and first calcining in sequence to obtain a composite molecular sieve; the molecular sieve is a ZSM-5 molecular sieve or an SSZ-13 molecular sieve; mixing a divalent copper salt, the composite molecular sieve and a second solvent, and loading to obtain a molecular sieve loaded with a precursor; and performing a second calcination on the molecular sieve loaded with a precursor to obtain a metal-supported composite molecular sieve catalyst. The present invention improves the carrier, adopts a ZSM-5 molecular sieve or SSZ-13 molecular sieve that is resistant to high temperature and has a large specific surface area, and composites it with γ-Al2O3 as a carrier, so that the carrier has a large specific surface area, a strong loading capacity, and has high chemical stability and adsorption capacity, so that the catalytic reaction is more sufficient, the loss of active components is reduced, and the stability of the catalyst is improved. Experimental results show that when the catalyst prepared by the present invention catalyzes hydrogen chloride to produce chlorine, the chlorine yield after 8 hours of reaction is 87.8-96.28%, and the chlorine yield after 1000 hours of reaction is 86.9-96.11%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a process flow chart for preparing metal-supported composite molecular sieve catalysts in Examples 2 to 8. DETAILED DESCRIPTION

[0022] The present invention provides a method for preparing a metal-supported composite molecular sieve catalyst, comprising the following steps:

[0023] (1) mixing a molecular sieve, γ-Al2O3 and a first solvent, and then drying and first calcining in sequence to obtain a composite molecular sieve; the molecular sieve is a ZSM-5 molecular sieve or a SSZ-13 molecular sieve;

[0024] (2) mixing the divalent copper salt, the composite molecular sieve obtained in step (1) and a second solvent, and performing a first loading to obtain a molecular sieve loaded with a precursor;

[0025] (3) subjecting the molecular sieve loaded with the precursor obtained in step (2) to a second calcination to obtain a metal-loaded composite molecular sieve catalyst.

[0026] The present invention has no particular limitation on the sources of the raw materials, and commercially available products known to those skilled in the art may be used.

[0027] In the present invention, the first, second and third have no special meanings and are only used to distinguish the steps.

[0028] The present invention mixes molecular sieve, gamma-Al2O3 and a first solvent, and then sequentially performs drying and a first calcination to obtain a composite molecular sieve.

[0029] In the present invention, the molecular sieve is a ZSM-5 molecular sieve or a SSZ-13 molecular sieve. The present invention adopts a ZSM-5 molecular sieve or a SSZ-13 molecular sieve which is resistant to high temperature and has a large specific surface area, and is composited with γ-Al2O3 as a carrier. γ-Al2O3 has a microporous structure and can form a micro-mesoporous composite molecular sieve with the molecular sieve, so that the carrier has a large specific surface area, a strong loading capacity, and high chemical stability and adsorption capacity, so that the catalytic reaction is more sufficient, the loss of active components is reduced, and the stability of the catalyst is improved.

[0030] In the present invention, the mass ratio of the molecular sieve to γ-Al2O3 is preferably (1-2): 1. The present invention can further improve the stability of the catalyst by controlling the mass ratio of the molecular sieve to γ-Al2O3.

[0031] In the present invention, the silicon-to-aluminum ratio of the molecular sieve is preferably 30 to 160. The present invention can further improve the catalytic activity of the catalyst by controlling the silicon-to-aluminum ratio of the molecular sieve.

[0032] In the present invention, the first solvent is preferably an inorganic solvent, more preferably water. The present invention has no particular limitation on the amount of the first solvent, and the first solvent can be used to dissolve the raw materials and reach a viscosity similar to toothpaste.

[0033] The present invention has no special limitation on the operation of mixing the molecular sieve, γ-Al2O3 and the first solvent, and the technical scheme for preparing the mixed material well known to those skilled in the art can be adopted.

[0034] After the mixing is completed, the present invention preferably allows the mixed solution to stand for a period of 10 to 12 hours. In the present invention, the standing after mixing can allow the molecular sieve and γ-Al2O3 to be mixed more evenly.

[0035] The present invention has no particular limitation on the drying operation, and the drying operation may be performed until the weight is constant.

[0036] After drying, the product obtained by drying is preferably ground. The grinding operation is not particularly limited in the present invention, and can be performed by operations well known to those skilled in the art. Grinding in the present invention is beneficial to subsequent calcination.

[0037] In the present invention, the temperature of the first calcination is preferably 400-450°C, more preferably 420-440°C; the time of the first calcination is preferably 2-5h, more preferably 3-4h. The calcination of the present invention can remove the crystallization water contained in the molecular sieve, so that it can achieve the actual activity and stability after full dehydration; at the same time, it can also stabilize the crystal structure: during the calcination process, the crystal structure of the molecular sieve will undergo certain rearrangements and changes, making its structure more stable, making the grain structure more complete, and the pore size more consistent, thereby improving the adsorption, separation and catalytic activity of the molecular sieve.

[0038] In the present invention, the first calcination is preferably performed in an air atmosphere.

[0039] After obtaining the composite molecular sieve, the present invention mixes the divalent copper salt, the composite molecular sieve and a second solvent, performs a first loading, and obtains a molecular sieve loaded with a precursor.

[0040] In the present invention, the divalent copper salt is preferably copper nitrate; the second solvent is preferably an inorganic solvent, more preferably water. The divalent copper salt in the present invention is a copper precursor for providing an active component. The present invention has no particular limitation on the amount of the second solvent, as long as the copper salt is saturated.

[0041] In the present invention, the mass ratio of copper ions in the divalent copper salt to the composite molecular sieve is preferably (4-16): 100, more preferably (8-10): 100. The present invention can further improve the loading effect by controlling the mass ratio of the divalent copper salt to the composite molecular sieve, thereby improving the stability of the catalyst.

[0042] In the present invention, the mixing of the divalent copper salt, the composite molecular sieve and the second solvent is preferably performed by mixing the divalent copper salt with the second solvent and then adding the composite molecular sieve.

[0043] The present invention has no particular limitation on the mixing operation, and any operation well known to those skilled in the art may be used.

[0044] In the present invention, the first loading is preferably carried out under static conditions; the static temperature is preferably room temperature; the static time is preferably 10 to 15 hours, more preferably 12 to 14 hours. The present invention can further improve the loading effect by controlling the loading temperature and time, thereby improving the stability of the catalyst.

[0045] After the first loading is completed, the present invention preferably sequentially dries and grinds the product obtained by the first loading to obtain a molecular sieve loaded with a precursor.

[0046] The present invention has no special limitation on the drying and grinding operations, and operations familiar to those skilled in the art can be used. The present invention uses drying to fully dry the solid; and uses grinding to facilitate subsequent roasting.

[0047] After obtaining the molecular sieve loaded with the precursor, the present invention performs a second calcination on the molecular sieve loaded with the precursor to obtain a metal-loaded composite molecular sieve catalyst.

[0048] In the present invention, the temperature of the second calcination is preferably 400-550°C, more preferably 450-500°C; the time of the second calcination is preferably 5-8h, more preferably 6-7h; the second calcination is preferably carried out in an air atmosphere. The present invention can further improve the calcination effect by controlling the calcination temperature and time, thereby improving the stability of the catalyst.

[0049] After the second calcination is completed, the present invention preferably further comprises mixing the product obtained from the second calcination, the third solvent and the metal salt, performing a second loading, and then performing a third calcination to obtain a metal-loaded composite molecular sieve catalyst.

[0050] In the present invention, the third solvent is preferably an inorganic solvent, more preferably water. The present invention has no particular limitation on the amount of the third solvent, as long as the amount is sufficient to saturate the metal salt.

[0051] In the present invention, the metal salt is preferably at least one of potassium nitrate, magnesium nitrate, strontium nitrate, yttrium nitrate, molybdenum nitrate and bismuth nitrate. The present invention modifies the catalyst by adding the above-mentioned additives, which can greatly inhibit the loss of copper components and has good stability.

[0052] In the present invention, when the metal salt is at least two of potassium nitrate, magnesium nitrate, strontium nitrate, yttrium nitrate, molybdenum nitrate and bismuth nitrate, the metal ions in the metal salts are preferably arranged in equal mass ratios.

[0053] In the present invention, the mass of the metal ions in the metal salt accounts for 2-5.5% of the mass of the composite molecular sieve, and more preferably 3.0-4.5%. The present invention can further improve the loading effect by controlling the ratio between the two, thereby improving the activity and stability of the catalyst.

[0054] In the present invention, the mixing of the product obtained by the second calcination, the third solvent and the metal salt is preferably performed by mixing the metal salt and the third solvent and then adding the product obtained by the second calcination.

[0055] The present invention has no particular limitation on the mixing operation, and any operation well known to those skilled in the art may be used.

[0056] In the present invention, the second loading is preferably carried out under static conditions; the static temperature is preferably room temperature; the static time is preferably 5 to 8 hours, more preferably 6 to 7 hours. The present invention can further improve the loading effect by controlling the loading temperature and time, thereby improving the activity and stability of the catalyst.

[0057] After the second loading is completed, the present invention preferably sequentially dries and grinds the product obtained from the second loading.

[0058] The present invention has no special limitation on the drying and grinding operations, and operations familiar to those skilled in the art can be used. The present invention uses drying to fully dry the solid; and uses grinding to facilitate subsequent roasting.

[0059] In the present invention, the temperature of the third calcination is preferably 400-550°C, more preferably 450-500°C; the time of the third calcination is preferably 3-5 hours; and the third calcination is preferably carried out in an air atmosphere. The present invention can further improve the calcination effect by controlling the calcination temperature and time, thereby improving the activity and stability of the catalyst.

[0060] The preparation method provided by the present invention has the characteristics of simple process and relatively low price. The added auxiliary agent does not contain precious metal components, which greatly reduces the cost. It does not contain elements such as toxic components, so it is relatively environmentally friendly and does not cause secondary pollution. Compared with the existing copper-containing catalyst, the present invention improves the carrier, adopts ZSM-5 molecular sieve or SSZ-13 molecular sieve which is resistant to high temperature and has a large specific surface area, and composites it with γ-Al2O3 as the carrier, so that the catalyst has a large specific surface area, a strong loading capacity, and high chemical stability and adsorption capacity, so that the catalytic reaction is more sufficient, the loss of active components is reduced, and the stability of the catalyst is improved. In addition, the addition of the auxiliary agent can greatly inhibit the loss of the copper component and has good stability. The catalyst has high activity and can achieve a high yield of chlorine at a large hydrogen chloride space velocity.

[0061] The present invention also provides a metal-supported composite molecular sieve catalyst prepared by the preparation method described in the above technical solution.

[0062] In the present invention, the metal-supported composite molecular sieve catalyst preferably comprises a composite molecular sieve and an active component supported on the composite molecular sieve;

[0063] The composite molecular sieve is ZSM-5 molecular sieve / SSZ-13 molecular sieve and γ-Al2O3; the active component preferably includes copper oxide; the copper content in the metal-supported composite molecular sieve catalyst is preferably 3-20wt%. The molecular sieve and γ-Al2O3 coexist in a dispersed manner in the composite molecular sieve of the present invention.

[0064] In the present invention, the active component preferably also includes at least one of potassium oxide, magnesium oxide, strontium oxide, yttrium oxide, molybdenum oxide and bismuth oxide; the content of at least one of potassium, magnesium, strontium, yttrium, molybdenum and bismuth nitrate in the metal-supported composite molecular sieve catalyst is preferably 1 to 10 wt%.

[0065] The catalyst provided by the invention has high activity and high stability.

[0066] The present invention also provides the use of the metal-supported composite molecular sieve catalyst described in the above technical solution in the catalytic oxidation of hydrogen chloride to produce chlorine.

[0067] The present invention has no special limitation on the operation of using the metal-supported composite molecular sieve catalyst in the catalytic oxidation of hydrogen chloride to produce chlorine, and the operation well known to those skilled in the art can be adopted.

[0068] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. 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.

[0069] Example 1

[0070] The preparation method of the metal-supported composite molecular sieve catalyst comprises the following steps:

[0071] (1) Dissolving ZSM-5 molecular sieve and γ-Al2O3 in water, mixing and stirring, standing at room temperature for 12 hours, drying in an oven at 110°C for 12 hours, and calcining in an air atmosphere at 400°C for 3 hours to obtain a composite molecular sieve; wherein the silicon-aluminum ratio of the ZSM-5 molecular sieve is 60; and the mass ratio of the ZSM-5 molecular sieve to the γ-Al2O3 is 1:1;

[0072] (2) 3.27 g of Cu(NO3)2·3H2O was dissolved in deionized water until saturated, and ultrasonicated at room temperature. Then, 10 g of the composite molecular sieve obtained in step (1) was added. After complete dissolution, the mixture was allowed to stand at room temperature for 12 h, heated to evaporate the water, and then dried in an oven at 110°C for 12 h. Then, the mixture was calcined in an air atmosphere at 500°C for 6 h to obtain a metal-supported composite molecular sieve catalyst.

[0073] Example 2

[0074] On the basis of Example 1, step (3) is added: 0.78 g of potassium nitrate is dissolved in water until saturated, ultrasonicated at room temperature for 30 min, then the copper-containing composite molecular sieve carrier obtained in step (2) is added, stirred for 2 h, allowed to stand at room temperature for 8 h, heated to evaporate water, dried in an oven at 110° C. for 12 h, ground, and then calcined at 500° C. in an air atmosphere for 5 h to obtain a metal-supported composite molecular sieve catalyst.

[0075] Example 3

[0076] The preparation method of the metal-supported composite molecular sieve catalyst comprises the following steps:

[0077] (1) Dissolving ZSM-5 molecular sieve and γ-Al2O3 in water, mixing and stirring, standing at room temperature for 12 hours, drying in an oven at 110°C for 12 hours, and calcining in an air atmosphere at 400°C for 3 hours to obtain a composite molecular sieve; wherein the silicon-aluminum ratio of the ZSM-5 molecular sieve is 60; and the mass ratio of the ZSM-5 molecular sieve to the γ-Al2O3 is 1:1;

[0078] (2) dissolving 3.27 g of Cu(NO3)2·3H2O in deionized water to saturation, ultrasonicating at room temperature, and then adding 10 g of the composite molecular sieve obtained in step (1). After complete dissolution, standing at room temperature for 12 h, heating to evaporate water, drying in an oven at 110°C for 12 h, and then calcining at 500°C in air atmosphere for 6 h to obtain a copper-containing composite molecular sieve carrier;

[0079] (3) Dissolve potassium nitrate and magnesium nitrate in water until saturated, ultrasonicate at room temperature for 30 minutes, then add the copper-containing composite molecular sieve carrier obtained in step (2), stir for 2 hours, stand at room temperature for 8 hours, heat to evaporate water, dry in an oven at 110° C. for 12 hours, grind, and then calcine in an air atmosphere at 500° C. for 5 hours to obtain a metal-supported composite molecular sieve catalyst; wherein the mass ratio of potassium ions in potassium nitrate to magnesium ions in magnesium nitrate is 1:1; the mass ratio of magnesium ions to the composite molecular sieve is 1.5:100, and the mass ratio of potassium ions to the composite molecular sieve is 1.5:100.

[0080] Example 4

[0081] The preparation method of the metal-supported composite molecular sieve catalyst comprises the following steps:

[0082] (1) Dissolving ZSM-5 molecular sieve and γ-Al2O3 in water, mixing and stirring, standing at room temperature for 12 hours, drying in an oven at 110°C for 12 hours, and calcining in an air atmosphere at 400°C for 3 hours to obtain a composite molecular sieve; wherein the silicon-aluminum ratio of the ZSM-5 molecular sieve is 60; and the mass ratio of the ZSM-5 molecular sieve to the γ-Al2O3 is 1:1;

[0083] (2) dissolving 3.27 g of Cu(NO3)2·3H2O in deionized water to saturation, ultrasonicating at room temperature, and then adding 10 g of the composite molecular sieve obtained in step (1). After complete dissolution, standing at room temperature for 12 h, heating to evaporate water, drying in an oven at 110°C for 12 h, and then calcining at 500°C in air atmosphere for 6 h to obtain a copper-containing composite molecular sieve carrier;

[0084] (3) Dissolve potassium nitrate and strontium nitrate in water until saturated, ultrasonicate at room temperature for 30 minutes, then add the copper-containing composite molecular sieve carrier obtained in step (2), stir for 2 hours, stand at room temperature for 8 hours, heat to evaporate water, dry in an oven at 110° C. for 12 hours, grind, and then calcine in an air atmosphere at 500° C. for 5 hours to obtain a metal-supported composite molecular sieve catalyst; wherein the mass ratio of potassium ions in potassium nitrate to strontium ions in strontium nitrate is 1:1; the mass ratio of strontium ions to the composite molecular sieve is 1.5:100, and the mass ratio of potassium ions to the composite molecular sieve is 1.5:100.

[0085] Example 5

[0086] The preparation method of the metal-supported composite molecular sieve catalyst comprises the following steps:

[0087] (1) Dissolving ZSM-5 molecular sieve and γ-Al2O3 in water, mixing and stirring, standing at room temperature for 12 hours, drying in an oven at 110°C for 12 hours, and calcining in an air atmosphere at 400°C for 3 hours to obtain a composite molecular sieve; wherein the silicon-aluminum ratio of the ZSM-5 molecular sieve is 60; and the mass ratio of the ZSM-5 molecular sieve to the γ-Al2O3 is 1:1;

[0088] (2) dissolving 3.27 g of Cu(NO3)2·3H2O in deionized water to saturation, ultrasonicating at room temperature, and then adding 10 g of the composite molecular sieve obtained in step (1). After complete dissolution, standing at room temperature for 12 h, heating to evaporate water, drying in an oven at 110°C for 12 h, and then calcining at 500°C in air atmosphere for 6 h to obtain a copper-containing composite molecular sieve carrier;

[0089] (3) Dissolve potassium nitrate and yttrium nitrate in water until saturated, ultrasonicate at room temperature for 30 minutes, then add the copper-containing composite molecular sieve carrier obtained in step (2), stir for 2 hours, stand at room temperature for 8 hours, heat to evaporate water, dry in an oven at 110°C for 12 hours, grind, and then calcine at 500°C in an air atmosphere for 5 hours to obtain a metal-supported composite molecular sieve catalyst; wherein the mass ratio of potassium nitrate to yttrium nitrate is 1:1; the mass ratio of yttrium ions to the composite molecular sieve is 1.5:100, and the mass ratio of potassium ions to the composite molecular sieve is 1.5:100.

[0090] Example 6

[0091] The preparation method of the metal-supported composite molecular sieve catalyst comprises the following steps:

[0092] (1) Dissolving ZSM-5 molecular sieve and γ-Al2O3 in water, mixing and stirring, standing at room temperature for 12 hours, drying in an oven at 110°C for 12 hours, and calcining in an air atmosphere at 400°C for 3 hours to obtain a composite molecular sieve; wherein the silicon-aluminum ratio of the ZSM-5 molecular sieve is 60; and the mass ratio of the ZSM-5 molecular sieve to the γ-Al2O3 is 1:1;

[0093] (2) dissolving 3.27 g of Cu(NO3)2·3H2O in deionized water to saturation, ultrasonicating at room temperature, and then adding 10 g of the composite molecular sieve obtained in step (1). After complete dissolution, standing at room temperature for 12 h, heating to evaporate water, drying in an oven at 110°C for 12 h, and then calcining at 500°C in air atmosphere for 6 h to obtain a copper-containing composite molecular sieve carrier;

[0094] (3) Dissolve potassium nitrate and molybdenum nitrate in water until saturated, ultrasonicate at room temperature for 30 minutes, then add the copper-containing composite molecular sieve carrier obtained in step (2), stir for 2 hours, stand at room temperature for 8 hours, heat to evaporate water, dry in an oven at 110°C for 12 hours, grind, and then calcine in an air atmosphere at 500°C for 5 hours to obtain a metal-supported composite molecular sieve catalyst; wherein the mass ratio of potassium ions in potassium nitrate to molybdenum ions in molybdenum nitrate is 1:1; the mass ratio of molybdenum ions to the composite molecular sieve is 1.5:100, and the mass ratio of potassium ions to the composite molecular sieve is 1.5:100.

[0095] Example 7

[0096] The preparation method of the metal-supported composite molecular sieve catalyst comprises the following steps:

[0097] (1) Dissolving ZSM-5 molecular sieve and γ-Al2O3 in water, mixing and stirring, standing at room temperature for 12 hours, drying in an oven at 110°C for 12 hours, and calcining in an air atmosphere at 400°C for 3 hours to obtain a composite molecular sieve; wherein the silicon-aluminum ratio of the ZSM-5 molecular sieve is 60; and the mass ratio of the ZSM-5 molecular sieve to the γ-Al2O3 is 1:1;

[0098] (2) dissolving 3.27 g of Cu(NO3)2·3H2O in deionized water to saturation, ultrasonicating at room temperature, and then adding 10 g of the composite molecular sieve obtained in step (1). After complete dissolution, standing at room temperature for 12 h, heating to evaporate water, drying in an oven at 110°C for 12 h, and then calcining at 500°C in air atmosphere for 6 h to obtain a copper-containing composite molecular sieve carrier;

[0099] (3) Dissolve potassium nitrate, molybdenum nitrate and magnesium nitrate in water until saturated, ultrasonicate at room temperature for 30 minutes, then add the copper-containing composite molecular sieve carrier obtained in step (2), stir for 2 hours, stand at room temperature for 8 hours, heat to evaporate water, dry in an oven at 110°C for 12 hours, grind, and then calcine in an air atmosphere at 500°C for 5 hours to obtain a metal-supported composite molecular sieve catalyst; wherein the mass ratio of potassium ions in potassium nitrate, molybdenum ions in molybdenum nitrate and magnesium ions in magnesium nitrate is 1:1:1; the mass ratio of magnesium ions to the composite molecular sieve is 1.5:100, the mass ratio of molybdenum ions to the composite molecular sieve is 1.5:100, and the mass ratio of potassium ions to the composite molecular sieve is 1.5:100.

[0100] Example 8

[0101] The preparation method of the metal-supported composite molecular sieve catalyst comprises the following steps:

[0102] (1) Dissolving SSZ-13 molecular sieve and γ-Al2O3 in water, mixing and stirring, standing at room temperature for 12 hours, drying in an oven at 110°C for 12 hours, and calcining in an air atmosphere at 400°C for 3 hours to obtain a composite molecular sieve; wherein the silicon-aluminum ratio of the SSZ-13 molecular sieve is 60; and the mass ratio of the SSZ-13 molecular sieve to the γ-Al2O3 is 1:1;

[0103] (2) dissolving 3.27 g of Cu(NO3)2·3H2O in deionized water to saturation, ultrasonicating at room temperature, and then adding 10 g of the composite molecular sieve obtained in step (1). After complete dissolution, standing at room temperature for 12 h, heating to evaporate water, drying in an oven at 110°C for 12 h, and then calcining at 500°C in air atmosphere for 6 h to obtain a copper-containing composite molecular sieve carrier;

[0104] (3) Dissolve potassium nitrate, molybdenum nitrate and magnesium nitrate in water until saturated, ultrasonicate at room temperature for 30 minutes, then add the copper-containing composite molecular sieve carrier obtained in step (2), stir for 2 hours, stand at room temperature for 8 hours, heat to evaporate water, dry in an oven at 110°C for 12 hours, grind, and then calcine in an air atmosphere at 500°C for 5 hours to obtain a metal-supported composite molecular sieve catalyst; wherein the mass ratio of potassium ions in potassium nitrate, molybdenum ions in molybdenum nitrate and magnesium ions in magnesium nitrate is 1:1:1; the mass ratio of magnesium ions to the composite molecular sieve is 1.5:100, the mass ratio of molybdenum ions to the composite molecular sieve is 1.5:100, and the mass ratio of potassium ions to the composite molecular sieve is 1.5:100.

[0105] The process flow chart of preparing metal-supported composite molecular sieve catalysts in Examples 2 to 8 is as follows: Figure 1 shown.

[0106] from Figure 1It can be seen that the preparation of the metal-supported composite molecular sieve catalyst of the present invention includes preparing the composite molecular sieve, loading the divalent copper salt, then calcining, then loading the auxiliary agent, and finally calcining.

[0107] Comparative Example 1

[0108] 3.27 g of Cu(NO3)2·3H2O was dissolved in deionized water until saturated, and ultrasonicated at room temperature. Then 10 g of γ-Al2O3 was added. After complete dissolution, the mixture was allowed to stand at room temperature for 12 h. After heating to evaporate the water, the mixture was dried in an oven at 110°C for 12 h, and calcined at 500°C in air atmosphere for 6 h to obtain a catalyst.

[0109] Comparative Example 2

[0110] 3.27 g of Cu(NO3)2·3H2O was dissolved in deionized water to saturation, ultrasonicated at room temperature, and then 10 g of ZSM-5 molecular sieve was added. After complete dissolution, the mixture was allowed to stand at room temperature for 12 h, dried in an oven at 110°C for 12 h, and calcined at 500°C in air atmosphere for 6 h to obtain a catalyst; wherein the silicon-aluminum ratio of the ZSM-5 molecular sieve was 60.

[0111] Comparative Example 3

[0112] 3.27 g of Cu(NO3)2·3H2O was dissolved in deionized water until saturated, and ultrasonicated at room temperature. Then, 10 g of ZSM-5 molecular sieve was added. After complete dissolution, the mixture was allowed to stand at room temperature for 12 h. After heating to evaporate the water, the mixture was dried in an oven at 110°C for 12 h, and calcined in an air atmosphere at 500°C for 6 h to obtain an intermediate product. Potassium nitrate, molybdenum nitrate and magnesium nitrate were then dissolved in water until saturated, and ultrasonicated at room temperature for 30 min. Then, the intermediate product was added, stirred for 2 h, and allowed to stand at room temperature for 8 h. After heating to evaporate the water, the catalyst was dried in an oven at 110°C for 12 hours, ground, and then calcined at 500°C in an air atmosphere for 5 hours to obtain a catalyst; wherein the silicon-aluminum ratio of the ZSM-5 molecular sieve is 60; wherein the mass ratio of potassium ions in potassium nitrate, molybdenum ions in molybdenum nitrate and magnesium ions in magnesium nitrate is 1:1:1; the mass ratio of magnesium ions to the composite molecular sieve is 1.5:100, the mass ratio of molybdenum ions to the composite molecular sieve is 1.5:100, and the mass ratio of potassium ions to the composite molecular sieve is 1.5:100.

[0113] The metal-supported composite molecular sieve catalysts prepared in Examples 1 to 8 and the catalysts prepared in Comparative Examples 1 to 3 were tableted using a tablet press, then ground and sieved to 20 to 40 meshes, and then loaded into a fixed bed reactor at a space velocity of 2.8 h -1The catalyst loading amount is 5 g. Under the conditions of a hydrogen chloride flow rate of 16 mL / min, a reaction temperature of 400°C, and a hydrogen chloride to oxygen flow ratio of 1:2, the chlorine yield (i.e., hydrogen chloride conversion rate) after 8 h and 1000 h of reaction at normal pressure is shown in Table 1.

[0114] Table 1 Hydrogen chloride conversion rate of the catalysts prepared in Examples 1 to 8 and Comparative Examples 1 to 3 after catalysis for 8 hours and 1000 hours

[0115]

[0116]

[0117] As can be seen from Table 1, through Examples 1 and 2, it can be seen that the modification of potassium further improves the performance of the catalyst; through Example 7 and Examples 2 to 6, it can be seen that the addition of magnesium, strontium, yttrium, molybdenum, and bismuth can further improve the performance of the catalyst, wherein the performance of adding multiple metals is more significant than that of adding one; the metal-supported composite molecular sieve catalyst prepared in the example has more excellent catalytic activity and stability compared with the comparative example, which is the result of the synergistic effect of the components, and the addition of potassium element and one or more additives of magnesium, strontium, yttrium, molybdenum, and bismuth metals is beneficial to improving the above-mentioned properties, so that the conversion rate of the catalyst is further increased to 96.28%.

[0118] It can be seen from the above comparative examples and embodiments that the metal-supported composite molecular sieve catalyst prepared by the preparation method provided by the present invention has high activity and high stability.

[0119] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a metal-supported composite molecular sieve catalyst comprises the following steps: (1) mixing a molecular sieve, γ-Al2O3 and a first solvent, allowing the mixed solution to stand, and then sequentially drying, grinding and first calcining to obtain a composite molecular sieve; the molecular sieve is a ZSM-5 molecular sieve or a SSZ-13 molecular sieve; (2) mixing the divalent copper salt, the composite molecular sieve obtained in step (1) and a second solvent, performing a first loading, and then sequentially drying and grinding the product obtained by the first loading to obtain a molecular sieve loaded with a precursor; (3) subjecting the molecular sieve loaded with the precursor obtained in step (2) to a second calcination, and after the second calcination is completed, mixing the product obtained by the second calcination, the third solvent and the metal salt, and subjecting the second loading to the second loading, and then sequentially drying and grinding the product obtained by the second loading, and then subjecting the product to a third calcination to obtain a metal-loaded composite molecular sieve catalyst; In the step (1), the mass ratio of the molecular sieve to γ-Al2O3 is 1:1; The metal salts are potassium nitrate and molybdenum nitrate; The mass ratio of potassium ions in potassium nitrate to molybdenum ions in molybdenum nitrate is 1:1; The mass ratio of the molybdenum ion to the composite molecular sieve is 1.5:100; The mass ratio of the potassium ions to the composite molecular sieve is 1.5:

100.

2. The preparation method according to claim 1, characterized in that: In the step (1), the temperature of the first calcination is 400-450° C., and the time of the first calcination is 2-5 hours.

3. The preparation method according to claim 1, characterized in that: The first loading in the step (2) is carried out under static conditions; the static temperature is room temperature, and the static time is 10 to 15 hours.

4. The preparation method according to claim 1, characterized in that: The temperature of the second calcination in step (3) is 400-550° C., and the time of the second calcination is 5-8 hours.

5. The preparation method according to claim 1, characterized in that: The temperature of the third calcination is 400-550° C., and the time of the third calcination is 3-5 hours.

6. The metal-supported composite molecular sieve catalyst prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the metal-supported composite molecular sieve catalyst according to claim 6 in the catalytic oxidation of hydrogen chloride to produce chlorine.

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