Spherical titanium silicon molecular sieve catalyst and its preparation method and application

Abstract

The present invention relates to catalyst preparation technology, and discloses a spherical titanium silicon molecular sieve catalyst, a preparation method and application thereof. The preparation method of the spherical titanium silicon molecular sieve catalyst comprises the following steps: a first raw material powder, a binder and a surfactant are subjected to a first mixing and granulation to form a molecular sieve wet ball; the molecular sieve wet ball is subjected to a second mixing and granulation with a second raw material powder, followed by drying and roasting; wherein the first raw material powder and the second raw material powder are titanium silicon molecular sieves, respectively. The present invention also provides the application of the spherical titanium silicon molecular sieve catalyst in the preparation of propylene oxide. The preparation method of the catalyst provided by the present invention is simple to operate, easy to control the particle size of the spheres, and has less specific surface area loss, better strength and excellent catalytic performance.

Description

Technical Field

[0001] The invention relates to a catalyst preparation technology, and in particular to a spherical titanium silicon molecular sieve catalyst and a preparation method and application thereof. Background Art

[0002] Molecular sieve catalysts have good effects in the application of organic synthesis reactions and petrochemicals. Titanium silicon molecular sieves have strong catalytic oxidation properties. When hydrogen peroxide or alkyl hydroperoxide is selected as the oxidant, it can directly participate in olefin epoxidation, aromatic hydroxylation, alcohol and amine oxidation reactions, and can also be used for oxidative desulfurization of petrochemical products, with broad application prospects.

[0003] When the titanium silicate catalysts of nano-scale powder and micron-scale spray particles are used for catalytic reactions in a slurry bed reactor, there is a problem of difficulty in separating the products. Preparing the titanium silicate into a certain shape to develop a fixed bed reaction process is an effective solution, and then the preparation of shaped catalysts with industrial application value and the study of their reaction performance become the key. Bars and spheres are more common catalyst shapes in the chemical industry, and their production processes are also relatively mature; bar catalysts have poor flow properties, difficulty in achieving uniform dense phase filling, easy to cause catalyst bed instability, and produce channeling, while spherical catalysts have the advantages of good flow properties, less wear, and convenient loading and unloading processes. Therefore, spherical titanium silicate catalysts have better market prospects.

[0004] At present, a variety of spherical titanium silicalite catalysts have been developed. For example, China Petrochemical Corporation built an HPPO industrial unit in 2014 and successfully tested it. The HPO-1 catalyst loaded in it is a spherical catalyst made from hollow titanium silicalite as the catalyst component after modification. However, there are still some shortcomings in the molding process of spherical titanium silicon molecular sieve catalysts. For example, patent CN112916040A discloses a catalyst for preparing propylene oxide by the HPPO method and a preparation method thereof. The modified TS-1 molecular sieve and the pore expander are placed in a ball rolling machine using a ball rolling device such as a turntable, a sugar coating pan or a drum. The modified TS-1 molecular sieve and the pore expander are continuously sprayed into the ball rolling machine while rolling to form the ball. After screening, balls with a diameter of 1.2-1.8 mm are taken, and the balls are treated with water vapor at 175°C for 10 hours to form a modified TS-1 molecular sieve / Silicalite-1 molecular sieve composite structure. The modified TS-1 molecular sieve / Silicalite-1 molecular sieve composite structure is then dried with hot air for 4 hours and calcined at 550°C for 5 hours to obtain a propylene oxide catalyst. The molding process in this method has the disadvantages of large dust during operation, long balling time, and high labor intensity. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems existing in the prior art and to provide a spherical titanium silicon molecular sieve catalyst and a preparation method and application thereof. The preparation method of the catalyst is simple to operate, easy to control the particle size of the spheres, and has small specific surface area loss, good strength and excellent catalytic performance.

[0006] In order to achieve the above object, the first aspect of the present invention provides a method for preparing a spherical titanium silicon molecular sieve catalyst, comprising the following steps:

[0007] (1) performing a first mixing and granulation of a first raw material powder, a binder and a surfactant to form a molecular sieve wet ball;

[0008] (2) subjecting the molecular sieve wet balls to a second mixing and granulating process with a second raw material powder, followed by drying and calcining;

[0009] Wherein, the first raw material powder and the second raw material powder are titanium silicon molecular sieves respectively.

[0010] Preferably, the dry basis content of the titanium silicate molecular sieve is 80-92% by weight.

[0011] Preferably, the dry basis SiO 2 The content is 96-99% by weight, TiO 2 The content is 1-4% by weight.

[0012] Preferably, the binder is a siliceous binder, more preferably silica sol and / or water glass.

[0013] Preferably, the surfactant is a nonionic surfactant, more preferably a silicone surfactant.

[0014] Preferably, based on 100 parts by weight of the dry weight of the first raw material powder and the second raw material powder, the amount of the binder is 0.6-11 parts by weight, and the amount of the surfactant is 0.1-6 parts by weight.

[0015] Preferably, based on 100 parts by weight of the dry weight of the first raw material powder and the second raw material powder, the amount of the binder is 1.4-6.5 parts by weight, and the amount of the surfactant is 0.28-2.8 parts by weight.

[0016] Preferably, the weight ratio of the first raw material powder to the second raw material powder is 1:0.1-0.4, more preferably 1:0.15-0.35.

[0017] Preferably, in step (1), the binder and the surfactant are mixed with the first raw material powder in the form of aqueous solutions, or both are mixed with water to form a blended liquid which is then mixed with the first raw material powder.

[0018] Preferably, the concentration of the binder in the aqueous solution of the binder or the blended liquid is 3-20% by weight, more preferably 5-15% by weight.

[0019] Preferably, the concentration of the surfactant in the aqueous solution of the surfactant or the blended liquid is 0.5-10 wt %, more preferably 1-6 wt %.

[0020] Preferably, the total weight of the aqueous solution of the binder and the aqueous solution of the surfactant or the weight of the mixed solution is 0.3-0.6 of the dry weight of the first raw material powder, and more preferably 0.4-0.5.

[0021] Preferably, the average particle size of the molecular sieve wet balls in step (1) is 1-1.5 mm, more preferably 1.1-1.4 mm.

[0022] Preferably, the conditions for the first mixing and granulation include: in a closed environment, the rotation speed of the stirring tool is 100-2000 rpm, and the rotation speed of the rotating mixing barrel is 30-50 rpm.

[0023] Preferably, the second mixing and granulating process in step (2) comprises: mixing the molecular sieve wet balls with the second raw material powder until the molecular sieve wet balls are no longer sticky.

[0024] Preferably, the second mixing and granulation conditions include: in a closed environment, the rotation speed of the stirring tool is 100-400 rpm, and the rotation speed of the rotating mixing barrel is 40-48 rpm.

[0025] Preferably, the drying conditions in step (2) include: a temperature of 50-80° C. and a time of 2-2.5 h.

[0026] Preferably, the calcination conditions include: a temperature of 550-600° C. and a time of 3-4 hours.

[0027] Preferably, the method further comprises: screening the dried microspheres and then calcining them.

[0028] Preferably, the screening process comprises: screening the dried microspheres with 12-mesh and 18-mesh sieves to obtain microspheres with a particle size of 12-18 mesh.

[0029] The second aspect of the present invention provides a spherical titanium silicon molecular sieve catalyst prepared by the above preparation method.

[0030] Preferably, the spherical titanium silicon molecular sieve catalyst has an average particle size of 1.1-1.5 mm and a specific surface area of ​​350-460 m 2 / g, pore volume is 0.20-0.26mL / g, and strength is 10-30N / particle.

[0031] The third aspect of the present invention provides the use of the above-mentioned spherical titanium silicalite catalyst in the preparation of propylene oxide.

[0032] Through the above technical scheme, the spherical titanium silicon molecular sieve catalyst provided by the present invention uses titanium silicon molecular sieve, a binder and a surfactant as raw materials, and adopts a rapid mixing granulation method to form a ball of the titanium silicon molecular sieve. Under the action of mechanical force, the powder particles of the titanium silicon molecular sieve collide and move together, and aggregate into nuclei under the action of capillary force. The formed spherical core gradually grows by stratification or agglomeration during the rolling and collision process. During the continued rolling and collision process, the spherical core is further compacted into a molecular sieve wet ball, and then the molecular sieve wet ball is contacted with the titanium silicon molecular sieve until it is no longer bonded. The entire forming process makes it easy to control the particle size of the ball, with less loss of specific surface area, low bulk density of the catalyst, good strength, simple operation, and short time consumption; it can also achieve mixing and granulation in a closed container to avoid large dust and effectively optimize the working environment.

[0033] The spherical titanium silicon molecular sieve catalyst provided by the present invention can effectively improve the selectivity and H of the target product in the process of catalytic preparation of propylene oxide. 2 O 2 conversion rate, thereby reducing the production cost of propylene oxide. DETAILED DESCRIPTION

[0034] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0035] The first aspect of the present invention provides a method for preparing a spherical titanium silicon molecular sieve catalyst, the preparation method comprising the following steps:

[0036] (1) performing a first mixing and granulation of a first raw material powder, a binder and a surfactant to form a molecular sieve wet ball;

[0037] (2) subjecting the molecular sieve wet balls to a second mixing and granulating process with a second raw material powder, followed by drying and calcining;

[0038] Wherein, the first raw material powder and the second raw material powder are titanium silicon molecular sieves respectively.

[0039] The spherical titanium silicon molecular sieve catalyst provided by the present invention uses titanium silicon molecular sieve, a binder and a surfactant as raw materials. The first mixed granulation and the second mixed granulation process both adopt a rolling ball method to form balls. During the first mixed granulation, under the action of mechanical force, the powder particles of the titanium silicon molecular sieve collide and move closer to each other, and aggregate into nuclei under the action of capillary force. The formed spherical cores gradually grow up through stratification or agglomeration during rolling and collision. During the continued rolling and collision process, the spherical cores are further compacted into molecular sieve wet balls. During the second mixed granulation, the molecular sieve wet balls are contacted with the titanium silicon molecular sieve, and rolling balls are further formed during rolling and collision. The entire forming process makes it easy to control the particle size of the balls, with less loss of specific surface area, low bulk density of the catalyst, good strength, simple operation and short time consumption. It can also be achieved that the mixed granulation is carried out in a closed container to avoid large dust and effectively optimize the working environment.

[0040] According to the present invention, preferably, the dry basis content of the titanium silicon molecular sieve is 80-92% by weight. The dry basis content of the titanium silicon molecular sieve specifically refers to the SiO 2 and TiO 2 The total content of

[0041] According to the present invention, preferably, the dry basis of the titanium silicon molecular sieve contains SiO 2 The content is 96-99% by weight, TiO 2 The content is 1-4% by weight.

[0042] According to the present invention, the binder may be a conventional binder material in the field of molecular sieves. Preferably, the binder is a siliceous binder, more preferably silica sol and / or water glass.

[0043] According to the present invention, the surfactant may be a conventional surfactant. Preferably, the surfactant is a nonionic surfactant, more preferably an organosilicon surfactant. Specifically, the surfactant may be γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, etc.

[0044] The above substances are all conventional choices in the art and can be obtained commercially.

[0045] According to the present invention, in order to further improve the catalytic performance and particle strength of the spherical titanium silicon molecular sieve catalyst, preferably, based on 100 parts by weight of the dry weight of the first raw material powder and the second raw material powder, the amount of the binder is 0.6-11 parts by weight, and the amount of the surfactant is 0.1-6 parts by weight.

[0046] Further preferably, based on 100 parts by weight of the dry weight of the first raw material powder and the second raw material powder, the amount of the binder is 1.4-6.5 parts by weight, and the amount of the surfactant is 0.28-2.8 parts by weight.

[0047] According to the present invention, preferably, the weight ratio of the first raw material powder to the second raw material powder is 1:0.1-0.4, more preferably 1:0.15-0.35.

[0048] According to the present invention, the binder and the surfactant in step (1) can be directly mixed with the first raw material powder. In order to improve the mixing uniformity of the first raw material powder, the binder and the surfactant and improve the efficiency of granulation, preferably, the binder and the surfactant are mixed with the first raw material powder in the form of an aqueous solution, or the binder and the surfactant are mixed with water to form a blended liquid and then mixed with the first raw material powder.

[0049] More preferably, the binder and the surfactant are mixed with water to form a blended liquid, and then mixed with the first raw material powder. Specifically, the binder and the surfactant are dissolved in water at a temperature of 30-50°C and stirred evenly to prepare a blended liquid. In the present invention, there is no specific limitation on the stirring conditions for dissolving the binder and the surfactant in water, and the conditions can be carried out under conditions familiar to those skilled in the art, as long as a uniform blended liquid can be prepared; there is no specific limitation on the order of dissolving the binder and the surfactant.

[0050] According to the present invention, preferably, the concentration of the binder in the aqueous solution of the binder or the blended liquid is 3-20% by weight, specifically 3% by weight, 7% by weight, 11% by weight, 15% by weight, 20% by weight, or any value in the range formed by any two of the above values, more preferably 5-15% by weight. It should be noted that the concentration of the binder in the present invention is calculated based on the weight of the binder product itself.

[0051] According to the present invention, preferably, the concentration of the surfactant in the aqueous solution of the surfactant or the blended liquid is 0.5-10 weight%, specifically 0.5 weight%, 3 weight%, 5.5 weight%, 8 weight%, 10 weight%, or any value in the range formed by any two of the above values, more preferably 1-6 weight%.

[0052] According to the present invention, in order to facilitate the control of the size of the molecular sieve wet bulb and improve the efficiency of granulation, preferably, the total weight of the aqueous solution of the binder and the aqueous solution of the surfactant or the weight of the mixed liquid is 0.3-0.6 of the dry weight of the first raw material powder, and more preferably 0.4-0.5.

[0053] According to the present invention, in order to better control the particle size of the molecular sieve wet ball, preferably, the average particle size of the molecular sieve wet ball in step (1) is 1-1.5mm, more preferably 1.1-1.4mm. Specifically, the first mixed granulation process includes: mixing and stirring the first raw material powder, the binder and the surfactant to form a molecular sieve wet ball with an average particle size of 1-1.5mm. Under this preferred embodiment, a molecular sieve wet ball with high sphericity and concentrated particle size can be obtained. In the present invention, the average particle size of the molecular sieve wet ball is obtained by sampling and measuring with a vernier caliper.

[0054] According to the present invention, preferably, the conditions for the first mixing and granulation include: in a closed environment, the rotation speed of the stirring tool is 100-2000rpm, specifically 100rpm, 500rpm, 1000rpm, 1500rpm, 2000rpm, or any value in the range formed by any two of the above values; the rotation speed of the rotating mixing barrel is 30-50rpm, specifically 30rpm, 35rpm, 40rpm, 45pm, 50rpm, or any value in the range formed by any two of the above values.

[0055] According to the present invention, preferably, the second mixing and granulating process in step (2) comprises: mixing the molecular sieve wet balls with a second raw material powder until the molecular sieve wet balls are no longer sticky, so that the molecular sieve wet balls are further formed.

[0056] According to the present invention, preferably, the conditions for the second mixing granulation include: in a closed environment, the rotation speed of the stirring tool is 100-400rpm, specifically 100rpm, 200rpm, 300rpm, 400rpm, or any value in the range formed by any two of the above values; the rotation speed of the rotating mixing barrel is 40-48rpm, specifically 40rpm, 42rpm, 44rpm, 46pm, 48rpm, or any value in the range formed by any two of the above values.

[0057] Exemplarily, the mixed preparation process of the spherical titanium silicon molecular sieve catalyst is carried out using a mixing granulator to achieve the above-mentioned first mixing granulation and second mixing granulation in a closed environment, specifically: after the first raw material powder is added to the mixing granulator, the equipment is started, and a mixed liquid of a binder and a surfactant is added, wherein the addition form of the mixed liquid is not specifically limited and can be carried out in a manner familiar to those skilled in the art. Preferably, the mixed liquid is added once through a pipeline; then the first mixing granulation is carried out to form molecular sieve wet balls with an average particle size of 1-1.5 mm; finally, the second raw material powder is added to the mixing granulator, and the second mixing granulation is carried out until the molecular sieve wet balls are no longer bonded.

[0058] According to the present invention, preferably, the drying conditions include: a temperature of 50-80°C, specifically 50°C, 60°C, 70°C, 80°C, or any value in the range formed by any two of the above values; a time of 2-2.5h, specifically 2h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, or any value in the range formed by any two of the above values.

[0059] According to the present invention, preferably, the roasting conditions include: a temperature of 550-600°C, specifically 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, or any value in the range formed by any two of the above values; a time of 3-4h, specifically 3h, 3.5h, 4h, or any value in the range formed by any two of the above values.

[0060] According to the present invention, in order to further control the particle size of the catalyst, preferably, the method further comprises: sieving the dried microspheres and then calcining them.

[0061] According to the present invention, preferably, the screening process comprises: screening the dried microspheres with 12 and 18 mesh screens to obtain microspheres with a particle size of 12-18 mesh.

[0062] According to a particularly preferred embodiment of the present invention, a method for preparing a spherical titanium silicon molecular sieve catalyst comprises the following steps:

[0063] (1) dissolving a binder and a surfactant in water at a temperature of 30-50° C. to form a blended liquid (the concentration of the binder is 3-20% by weight, and the concentration of the surfactant is 0.5-10% by weight), mixing the first raw material powder with the blended liquid in a closed environment (the weight of the blended liquid is 0.3-0.6 of the dry weight of the first raw material powder), and performing a first mixing granulation (the speed of the stirring tool is 100-2000 rpm, and the speed of the rotating mixing barrel is 30-50 rpm) to form a molecular sieve wet ball with an average particle size of 1-1.5 mm;

[0064] (2) performing a second mixing granulation on the molecular sieve wet balls and the second raw material powder (the stirring tool speed is 100-400 rpm, and the rotating mixing barrel speed is 40-48 rpm) until the molecular sieve wet balls are no longer bonded, and then drying at a temperature of 50-80° C. for 2-2.5 h, and then sieving with 12 and 18 mesh screens to obtain microspheres with a particle size of 12-18 mesh, and finally calcining at a temperature of 550-600° C. for 3-4 h;

[0065] The first raw powder and the second raw powder are titanium silicon molecular sieves respectively, and the weight ratio of the first raw powder to the second raw powder is 1:0.1-0.4. Based on the dry weight of the first raw powder and the second raw powder as 100 parts by weight, the amount of the binder used is 0.6-11 parts by weight, and the amount of the surfactant used is 0.1-6 parts by weight.

[0066] The second aspect of the present invention provides a spherical titanium silicon molecular sieve catalyst prepared by the above preparation method.

[0067] According to the present invention, preferably, the spherical titanium silicon molecular sieve catalyst has an average particle size of 1.1-1.5 mm and a specific surface area of ​​350-460 m 2 / g, pore volume is 0.20-0.26mL / g, and strength is 10-30N / particle. The average particle size of the spherical titanium silicalite catalyst is measured by a vernier caliper, the specific surface area is measured by a nitrogen adsorption method, the pore volume is measured by a nitrogen adsorption method, and the strength is measured by a radial crushing strength method.

[0068] According to the present invention, the bulk density of the spherical titanium silicon molecular sieve catalyst is 0.6-0.7 g / cm 3 , determined by the measuring cylinder method.

[0069] The spherical titanium silicon molecular sieve catalyst provided by the present invention has low bulk density, good strength and good catalytic performance. Therefore, the third aspect of the present invention provides the use of the above-mentioned spherical titanium silicon molecular sieve catalyst in the preparation of propylene oxide. In the process of catalytic preparation of propylene oxide, the selectivity and H of the target product can be effectively improved. 2 O 2 conversion rate, thereby reducing the production cost of propylene oxide.

[0070] The present invention will be described in detail below through examples.

[0071] In the following examples, titanium silicon molecular sieve was purchased from Hunan Jianchang Petrochemical Co., Ltd. and had a specific surface area of ​​430 m 2 / g, pore volume is 0.25ml / g, dry basis content is 88.5 wt%; the dry basis content of titanium silicon molecular sieve is SiO 2 The content is 97.5% by weight, TiO 2The content is 2.5 weight %; the binder is silica sol, purchased from Yueyang Kelida Chemical Technology Co., Ltd., model NSA-520, with a silicon dioxide content of 20-21%, a particle dispersion of 5-6nm, and a pH of 2-4; the silicone surfactant is γ-aminopropyltriethoxysilane, purchased from Shandong Xinbaihe Chemical Technology Co., Ltd., model KH550; other raw materials and reagents are conventional commercial products; the rapid mixing granulator is purchased from Jilin Jiuqiang Machinery Preparation Company; the average particle size of the first wet bulb is measured by a vernier caliper, the average particle size of the spherical titanium silicon molecular sieve catalyst is measured by a vernier caliper, the specific surface area is measured by a nitrogen adsorption method, the pore volume is measured by a nitrogen adsorption method, the bulk density is measured by a measuring cylinder method, and the strength is measured by a radial crushing strength method.

[0072] In the following examples, the reaction process of the direct oxidation of hydrogen peroxide to prepare propylene oxide (HPPO reaction) is as follows: the spherical titanium silicon molecular sieve catalyst obtained in the examples or comparative examples is fixed in a reactor, the epoxidation reaction of propylene and hydrogen peroxide is carried out in a jacketed tubular fixed bed reactor, the catalyst is shaped into short strips of about 5 mm in length, and its maximum loading amount is 100 mL, the temperature of the reactor is adjusted by an automatic thermostatic oil bath flowing through the reactor jacket, and the pressure of the reactor is adjusted to 0.4 MPa by a back pressure valve on the reactor outlet pipeline and maintained by nitrogen; propylene, aqueous hydrogen peroxide solution and methanol are respectively fed into the reactor by three metering pumps, and the epoxidation reaction of propylene and hydrogen peroxide is carried out under the conditions of a reaction tube jacket oil bath temperature of 50° C., a reaction pressure of 0.4 MPa, a feed molar ratio of propylene to hydrogen peroxide of 2.5:1, a feed molar ratio of methanol to propylene of 5:1, a feed mass space velocity of hydrogen peroxide of 0.14 h-1 and the addition of 0.01% of ammonium hydroxide to the reaction feed;

[0073] H in the reactor feed and discharge 2 O 2 The content of propylene oxide was determined by indirect iodine titration, and the content of propylene oxide and its ring-opening by-products in the reactor output was determined by gas chromatography;

[0074] H 2 O 2 The conversion rate is calculated according to the following formula:

[0075]

[0076] The selectivity of propylene oxide (PO selectivity) refers to the mole percentage of propylene oxide in the epoxidation reaction product and is calculated by the following formula:

[0077]

[0078] Example 1

[0079] (1) 0.5 kg of silica sol as a binder and 0.3 kg of an organic silicon surfactant were dissolved in 6 L of water at 40° C. and stirred evenly to prepare a blended liquid, 15 kg of titanium silicon molecular sieve was used as the first raw material powder and added to a mixing granulator. After the mixing granulator was started, the blended liquid was added at one time through the pipeline, and then the first mixing granulation was carried out under the conditions of a stirring tool speed of 1200 rpm and a rotating mixing barrel speed of 30 rpm. When the powder particles aggregated and nucleated to form a molecular sieve wet ball with a particle size of about 1.2 mm;

[0080] (2) The mixing granulator was adjusted to a stirring tool speed of 400 rpm and a rotating mixing barrel speed of 45 rpm, 2.5 kg of titanium silicon molecular sieve was added as the second raw material powder, and the second mixing granulation was performed. The stirring and mixing was stopped when the wet balls of the molecular sieve were no longer sticky (the first mixing granulation and the second mixing granulation took a total of 35 min), and then the microspheres were dried at 70°C for 2.5 h to obtain microspheres. The microspheres were sieved using standard 12-mesh and 18-mesh sieves to obtain microspheres with a particle size of 12-18 mesh, and then calcined at 580°C for 4 h to obtain spherical titanium silicon molecular sieve catalysts with a ball diameter of 1.1-1.5 mm.

[0081] The physicochemical properties and HPPO reaction performance of the spherical titanium silicalite catalyst prepared in Example 1 were tested. The results are shown in Table 1.

[0082] Example 2

[0083] (1) 0.3 kg of silica sol as a binder and 0.1 kg of an organic silicon surfactant were dissolved in 6 L of water at 30° C. and stirred evenly to prepare a blended liquid, 16.95 kg of titanium silicon molecular sieve was used as the first raw material powder and added to a mixing granulator. After the mixing granulator was started, the blended liquid was added at one time through the pipeline, and then the first mixing granulation was carried out under the conditions of a stirring tool speed of 1000 rpm and a rotating mixing barrel speed of 50 rpm. When the powder particles aggregated and nucleated to form a molecular sieve wet ball with a particle size of about 1.2 mm;

[0084] (2) The mixing granulator was adjusted to a stirring tool speed of 300 rpm and a rotating mixing barrel speed of 40 rpm, 3 kg of titanium silicon molecular sieve was added as the second raw material powder, and the second mixing granulation was performed. The stirring and mixing was stopped when the wet balls of the molecular sieve were no longer sticky (the first mixing granulation and the second mixing granulation took a total of 38 min), and then the microspheres were dried at 50°C for 2.5 h to obtain microspheres. The microspheres were sieved using standard sieves of 12 mesh and 18 mesh, and microspheres with a particle size of 12-18 mesh were taken. The microspheres were then calcined at 550°C for 4 h to obtain spherical titanium silicon molecular sieve catalysts with a ball diameter of 1.1-1.5 mm.

[0085] The physicochemical properties and HPPO reaction performance of the spherical titanium silicalite catalyst prepared in Example 2 were tested, and the results are shown in Table 1.

[0086] Example 3

[0087] (1) 0.9 kg of silica sol as a binder and 0.4 kg of an organic silicon surfactant were dissolved in 6 L of water at 50° C. and stirred evenly to prepare a blended liquid, 15 kg of titanium silicon molecular sieve was used as the first raw material powder and added to a mixing granulator. After the mixing granulator was started, the blended liquid was added at one time through the pipeline, and then the first mixing granulation was carried out under the conditions of a stirring tool speed of 2000 rpm and a rotating mixing barrel speed of 30 rpm. When the powder particles aggregated and nucleated to form a molecular sieve wet ball with a particle size of about 1.2 mm;

[0088] (2) The mixing granulator was adjusted to a stirring tool speed of 100 rpm and a rotating mixing barrel speed of 48 rpm, 2.5 kg of titanium silicon molecular sieve was added as the second raw material powder, and the second mixing granulation was performed. The stirring and mixing was stopped when the wet balls of the molecular sieve were no longer sticky (the first mixing granulation and the second mixing granulation took a total of 30 min), and then dried at 80°C for 2 h to obtain microspheres. The microspheres were sieved using standard 12-mesh and 18-mesh sieves to obtain microspheres with a particle size of 12-18 mesh, and then calcined at 600°C for 3 h to obtain spherical titanium silicon molecular sieve catalysts with a ball diameter of 1.1-1.5 mm.

[0089] The physicochemical properties and HPPO reaction performance of the spherical titanium silicalite catalyst prepared in Example 3 were tested. The results are shown in Table 1.

[0090] Example 4

[0091] Spherical titanium silicalite catalyst was prepared according to the method of Example 3, except that in step (1), the first raw material powder was 24 kg titanium silicalite, the amount of silica sol as binder was 2.5 kg, the amount of silicone surfactant was 1.2 kg, and the amount of water was 8.8 L; in step (2), the second raw material powder was 4 kg titanium silicalite, and the first mixed granulation and the second mixed granulation took a total of 33 min.

[0092] The physicochemical properties and HPPO reaction performance of the spherical titanium silicalite catalyst prepared in Example 4 were tested. The results are shown in Table 1.

[0093] Example 5

[0094] Spherical titanium silicalite catalyst was prepared according to the method of Example 3, except that in step (1), the amount of silica sol used as the binder was 0.16 kg, the amount of silicone surfactant used was 0.03 kg, and the amount of water used was 5 L; in step (2), the second raw material powder was 5 kg titanium silicalite, and the first mixed granulation and the second mixed granulation took a total of 52 min.

[0095] The physicochemical properties and HPPO reaction performance of the spherical titanium silicalite catalyst prepared in Example 5 were tested. The results are shown in Table 1.

[0096] Example 6

[0097] Spherical titanium silicalite catalyst was prepared according to the method of Example 3, except that in step (1), the first raw material powder was 15 kg titanium silicalite, the amount of silica sol as binder was 2 kg, the amount of silicone surfactant was 1 kg, and the amount of water was 4 L; in step (2), the second raw material powder was 4 kg titanium silicalite, and the first mixed granulation and the second mixed granulation took a total of 55 min.

[0098] The physicochemical properties and HPPO reaction performance of the spherical titanium silicalite catalyst prepared in Example 6 were tested. The results are shown in Table 1.

[0099] Example 7

[0100] The spherical titanium silicalite catalyst was prepared according to the method of Example 3, except that the amount of water used in step (1) was 8 L, and the first mixing granulation and the second mixing granulation took a total of 10 minutes.

[0101] The physicochemical properties and HPPO reaction performance of the spherical titanium silicalite catalyst prepared in Example 7 were tested. The results are shown in Table 1.

[0102] Example 8

[0103] Spherical titanium silicon molecular sieve catalyst was prepared according to the method of Example 3, except that the amount of titanium silicon molecular sieve used as the first raw material powder in step (1) was 10 kg, the amount of titanium silicon molecular sieve used as the second raw material powder in step (2) was 7.5 kg, and the first mixed granulation and the second mixed granulation took a total of 6 minutes.

[0104] The physicochemical properties and HPPO reaction performance of the spherical titanium silicalite catalyst prepared in Example 8 were tested. The results are shown in Table 1.

[0105] Comparative Example 1

[0106] (1) 2 kg of silica sol as a binder and 0.4 kg of an organic silicon surfactant were dissolved in 24 L of water to prepare a mixed solution, and 20 L of the mixed solution was sprayed into a sugar coating machine containing 30 kg of titanium silicalite molecular sieve using a spray pipe, and the mother ball was obtained by stirring (taking 8 hours);

[0107] (2) The mother ball is crushed, and particles below 30 mesh are taken as new mother balls. By repeatedly adding the blending liquid and titanium silicalite, the particles gradually grow into balls. When the small balls are about 1.1-1.5 mm (total time is 28 hours), they are dried at 70°C for 2.5 hours to obtain microspheres. The microspheres are sieved with standard sieves of 12 mesh and 18 mesh, and microspheres with a particle size of 12-18 mesh are taken. The microspheres are then calcined at 580°C for 4 hours to obtain spherical titanium silicalite catalysts with a ball diameter of 1.1-1.5 mm.

[0108] The physicochemical properties and HPPO reaction performance of the spherical titanium silicalite catalyst prepared in Comparative Example 1 were tested, and the results are shown in Table 1.

[0109] Comparative Example 2

[0110] 2.5L of 65 wt% concentrated nitric acid was dissolved in 55L of water as a binder. 120kg of titanium silicon molecular sieve was mixed with the binder and extruded through a cylindrical orifice plate with an aperture of 1.6mm. The pellets were processed by a shaping machine to obtain spherical particles (taking about 8h). The particles were then dried at 70°C for 2.5h to obtain microspheres. The microspheres were sieved through standard sieves of 8 and 12 meshes, and microspheres with a particle size of 8-12 mesh were taken. The microspheres were then calcined at 580°C for 4h to obtain spherical titanium silicon molecular sieve catalysts with a diameter of 1.5-2mm.

[0111] The physicochemical properties and HPPO reaction performance of the spherical titanium silicalite catalyst prepared in Comparative Example 2 were tested, and the results are shown in Table 1.

[0112] Comparative Example 3

[0113] The spherical titanium silicon molecular sieve catalyst was prepared according to the method of Example 3, except that step (1) was replaced by:

[0114] (1) 1 kg of binder silica sol was dissolved in 6 L of water at 50° C. and stirred evenly to prepare a binder solution. 15 kg of titanium silicon molecular sieve was used as the first raw material powder and added to a mixing granulator. After the mixing granulator was started, the binder solution was added at one time through the pipeline. Then, the first mixing granulation was carried out under the conditions of a stirring tool speed of 2000 rpm and a rotating mixing barrel speed of 30 rpm to form molecular sieve wet balls; the first mixing granulation and the second mixing granulation took a total of 30 minutes.

[0115] The physicochemical properties and HPPO reaction performance of the spherical titanium silicalite catalyst prepared in Comparative Example 3 were tested, and the results are shown in Table 1.

[0116] Table 1

[0117]

[0118] It can be seen from the results in Table 1 that the spherical titanium silicon molecular sieve catalyst prepared by the method of the present invention has less specific surface area loss, low catalyst bulk density, high particle strength, easy control of spherical particle size, and short time consumption; in addition, the preparation method of the present invention is not only simple to operate, but also carried out in a closed container, which is friendly to the working environment, and the prepared catalyst has high selectivity for propylene oxide (PO), H 2 O 2 The conversion rate is also better than that of the catalyst prepared in the comparative example, and the production cost of propylene oxide can be effectively reduced.

[0119] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a spherical titanium silicon molecular sieve catalyst, characterized in that: The preparation method comprises the following steps: (1) performing a first mixing and granulation on a first raw material powder, a binder and a surfactant to form a molecular sieve wet ball with an average particle size of 1-1.5 mm, wherein the surfactant is γ-aminopropyltriethoxysilane and / or γ-aminopropyltrimethoxysilane; (2) subjecting the molecular sieve wet balls to a second mixing and granulating process with a second raw material powder, followed by drying and roasting; Wherein, the first raw material powder and the second raw material powder are titanium silicon molecular sieve respectively; based on 100 parts by weight of the dry basis weight of the first raw material powder and the second raw material powder, the amount of the binder is 1.4-6.5 parts by weight, and the amount of the surfactant is 0.28-2.8 parts by weight; The weight ratio of the first raw material powder to the second raw material powder is 1:0.1-0.4; In step (1), the binder and the surfactant are mixed with the first raw material powder in the form of aqueous solutions, or the binder and the surfactant are mixed with water to form a blended liquid, and then mixed with the first raw material powder. The total weight of the aqueous solution of the binder and the aqueous solution of the surfactant or the weight of the blended liquid is 0.3-0.6 of the dry weight of the first raw material powder. The average particle size of the spherical titanium silicon molecular sieve catalyst is 1.1-1.5 mm, and the strength is 12.3-14.1 N / particle.

2. The preparation method according to claim 1, wherein The dry basis content of the titanium silicate molecular sieve is 80-92% by weight; The SiO2 content of the titanium silicalite molecular sieve on a dry basis is 96-99% by weight, and the TiO2 content is 1-4% by weight.

3. The preparation method according to claim 2, wherein The adhesive is a siliceous adhesive.

4. The preparation method according to claim 3, wherein The binder is silica sol and / or water glass.

5. The preparation method according to any one of claims 1 to 4, wherein: The concentration of the binder in the aqueous solution of the binder or the blended liquid is 3-20% by weight.

6. The preparation method according to claim 5, wherein: The concentration of the surfactant in the aqueous solution of the surfactant or the blended liquid is 0.5-10% by weight.

7. The preparation method according to any one of claims 1 to 4, wherein: The conditions for the first mixing and granulation in step (1) include: in a closed environment, the rotation speed of the stirring tool is 100-2000 rpm, and the rotation speed of the rotating mixing barrel is 30-50 rpm.

8. The preparation method according to any one of claims 1 to 4, wherein: The second mixing and granulation process in step (2) includes: mixing the molecular sieve wet balls with the second raw material powder until the molecular sieve wet balls are no longer sticky; the conditions for the second mixing and granulation include: in a closed environment, the speed of the stirring tool is 100-400 rpm, and the speed of the rotating mixing barrel is 40-48 rpm.

9. The preparation method according to any one of claims 1 to 4, wherein: The drying conditions in step (2) include: a temperature of 50-80°C and a time of 2-2.5 hours; The calcination conditions include: a temperature of 550-600° C. and a time of 3-4 hours.

10. The preparation method according to claim 9, wherein: The method further comprises: screening the dried microspheres and then calcining them; The screening process includes: screening the dried microspheres with 12-mesh and 18-mesh sieves to obtain microspheres with a particle size of 12-18 mesh.

11. A spherical titanium silicon molecular sieve catalyst prepared according to the preparation method according to any one of claims 1 to 10.

12. The spherical titanium silicon molecular sieve catalyst according to claim 11, wherein: The specific surface area of ​​the spherical titanium silicate catalyst is 350-460m 2 / g, pore volume is 0.20-0.26mL / g.

13. Use of the spherical titanium silicon molecular sieve catalyst according to claim 11 or 12 in the preparation of propylene oxide.

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