Method for preparing catalyst microspheres by supergravity method

Abstract

The invention belongs to the technical field of catalyst preparation, and particularly relates to a method for preparing catalyst microspheres by a supergravity method, which comprises the following steps of: 1, premixing: preliminarily mixing silica sol containing silicon dioxide and a catalyst in proportion to form slurry, pumping the mixed slurry into a supergravity device by using a peristaltic pump, and intensively mixing to obtain mixed slurry; uniformly distributed catalyst slurry is obtained; and 2, spray molding of the catalyst slurry: carrying out spray molding on the catalyst slurry obtained in the step 1 by a supergravity machine, and then carrying out high-temperature calcination to obtain the catalyst microspheres. According to the invention, the premixed slurry is reinforced through supergravity, and then the catalyst microspheres with uniform particle sizes are formed through the supergravity spray head, so that the obtained catalyst microspheres have higher sphericity and more uniform particle sizes, the activity of the spherical catalyst is kept stable, and the original primary powder level of the catalyst can be kept. The industrialization is relatively easy to realize, and the high activity of the catalyst is ensured, and the mechanical strength and the recycling convenience of the catalyst are also ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of catalyst preparation, and in particular relates to a method for preparing catalyst microspheres using a supergravity method. Background Art

[0002] Catalyst is a material with uniform microporous structure, good hydrothermal stability and catalytic function, and is widely used. However, the catalyst powder is fine, difficult to recycle, easy to lose, and the powder is not suitable for direct loading into large chemical equipment. In order to make the catalyst have a suitable shape, size and mechanical strength so as to be suitable for catalytic reactions and catalytic devices, a catalyst that meets the reaction and device can be obtained through processing and molding, and the molded catalyst has a certain catalytic activity and selectivity, which can extend the service life.

[0003] At present, the catalyst forming method mainly includes compression forming, extrusion forming, rotation forming, spray drying forming and oil forming. Among them, the spray drying forming technology has the following advantages: the first is that the granulation drying is completed in one step, the process is simple, the operation is convenient and easy to industrialize; the second is that the material atomized dispersion is directly and fully contacted with the heat source, the heat transfer effect is good, the drying instant is completed in a short time, the solid content of the export material is stable and the particle size distribution is uniform; the third is that the drying is carried out in a closed container, avoiding the influence of the production environment on the material, the product purity is high, and environmental pollution is reduced. Spray forming is the main method for preparing microspheres. Chinese patent CN103212435A mixes the organic amine template with the binder silica sol, mixes evenly after adding titanium silicon molecular sieve, obtains the microsphere titanium silicon molecular sieve intermediate product through spray forming, and then the intermediate product is treated under hydrothermal conditions for a certain time, and conventional filtration, drying and roasting are used to obtain titanium silicon molecular sieve catalyst microspheres. The catalytic activity of the obtained catalyst is significantly improved, reaching the level of the original powder of titanium silicon molecular sieve before forming, and there is no special production equipment and process requirements, which is easy to industrialize. The Chinese patent CN112062138A molecular sieve synthesis mother liquor does not need to be separated. After being directly mixed with kaolin and a binder and sprayed into shape, the silicon source, aluminum source and phosphorus source that are not fully crystallized in the mother liquor are converted into molecular sieve crystals during the solid phase crystallization process, thereby improving the methanol conversion activity of the catalyst and greatly reducing the discharge of the mother liquor.

[0004] The present invention strengthens the premixed slurry according to supergravity, so that the catalyst is dispersed more evenly, which helps to improve the sphericity of the catalyst microspheres. At the same time, the supergravity spray head can effectively control the size of the microspheres to prevent the droplets formed by the spray from being too large, resulting in the rupture of the microspheres and the failure to form, thereby further improving the molding degree of the catalyst microspheres and the efficiency of supergravity spray molding. The catalyst microspheres prepared by the present invention have good activity and diffusion properties, and can be directly applied to the production reaction process using a kettle reactor and a slurry bed reactor. The technology of preparing catalyst microspheres by supergravity is of great significance to improving the strength and activity of the catalyst, solving the separation, loss, recovery of the catalyst and extending the life of the catalyst. It has important research value for the engineering amplification preparation of the catalyst, improving the comprehensive performance of the catalyst and ensuring the stable operation of the reaction device. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing catalyst microspheres by ultra-gravity method in view of the above-mentioned technical problems, which can ensure the high activity of the catalyst on the one hand and the mechanical strength and convenient recovery of the catalyst on the other hand.

[0006] In view of this, the present invention provides a method for preparing catalyst microspheres by a high gravity method, comprising the following steps:

[0007] The first step is to premix the catalyst slurry under ultra-gravity: After the silica sol containing silicon dioxide and the catalyst are preliminarily mixed into a slurry according to a certain proportion, the mixed slurry is pumped into an ultra-gravity device by a peristaltic pump for enhanced mixing to obtain a uniform catalyst slurry;

[0008] The second step is the spray molding of the catalyst slurry: the catalyst slurry obtained in the first step is machine-sprayed and then calcined at high temperature to obtain catalyst microspheres.

[0009] In this technical solution, the premixed slurry is strengthened by ultra-gravity, and then the catalyst microspheres with uniform particle size are formed by spraying, so that the sphericity of the catalyst microspheres is higher and the particle size is more uniform. The activity of the spherical catalyst is not reduced, and the level of the original catalyst powder is reached. It is relatively easy to realize industrialization. On the one hand, it can ensure the high activity of the catalyst, and on the other hand, it can ensure the mechanical strength and recovery convenience of the catalyst.

[0010] Furthermore, the type of catalyst is one or more of titanium silicon molecular sieve catalyst, ZSM-5 molecular sieve catalyst, SAPO-34 molecular sieve catalyst, and TS-1 molecular sieve catalyst.

[0011] Furthermore, the silica sol containing silicon dioxide and the catalyst are mixed in a ratio of silicon dioxide to catalyst of 1:0.05-0.8 by mass.

[0012] Furthermore, the rotation speed of the ultra-gravity device is 10-60HZ, and the ultra-gravity enhanced mixing time is 0.5-5h.

[0013] Furthermore, the feed rate of the spray forming is 10-300 mL / min, and the rotation speed of the supergravity spray rotating disk of the spray forming is 200-300 Hz.

[0014] The beneficial effects of the present invention are:

[0015] 1. The catalytic activity of the catalyst microspheres obtained by spray molding using conventional technology is significantly reduced, while the catalytic activity of the catalyst microspheres obtained in this application is significantly higher than that of the catalyst prepared by conventional technology, and reaches the level of the original catalyst powder. After the slurry is premixed by supergravity, the original powder is dispersed more evenly, the ball formation rate is further improved, and the morphology of the catalyst microspheres remains unchanged under conventional kettle mechanical stirring, and the sphericity of the catalyst microspheres is more uniform and the particle size is more uniform. The activity of the spherical catalyst remains stable, reaching the level of the original catalyst powder, and it is relatively easy to achieve industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a SEM image of the spray-formed catalyst microspheres of Example 1;

[0017] Figure 2 This is a SEM image of the spray-formed catalyst microspheres of Example 2;

[0018] Figure 3 This is the SEM image of the spray-formed catalyst microspheres of Example 3;

[0019] Figure 4 This is a SEM image of the spray-formed catalyst microspheres of Example 4;

[0020] Figure 5 This is the SEM image of the spray-formed catalyst microspheres of Example 5. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0022] In the description of the present application, it should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. For ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0024] It should be noted that, in the description of the present application, the orientation or positional relationship indicated by terms such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise stated, these orientation words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present application; the orientation words "inside and outside" refer to the inside and outside relative to the contour of each component itself.

[0025] It should be noted that, in the present application, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises one..." does not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be noted that the scope of the method and device in the embodiment of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0026] Comparative Example 1

[0027] The titanium silicon molecular sieve catalyst powder catalyst is used for the catalytic oxidation of butanone to butanone oxime reaction of butanone, the catalyst, tert-butyl alcohol and butanone are evenly mixed in a three-necked flask, the temperature is raised and maintained at 70°C, and then a hydrogen peroxide solution and an ammonia solution are added to the three-necked flask at a speed of 1.0 mL / min by a micro-feed pump, and the reaction is continued at a constant temperature for 35 minutes after the hydrogen peroxide and ammonia solutions are added, and the reaction ends. The reaction product is analyzed by a gas chromatograph (Sh imadzu14B, F ID), and the conversion rate of butanone and the selectivity of butanone oxime are calculated by the area normalization method.

[0028] Comparative Example 2

[0029] 32 g ZSM-5 catalyst powder was dried at 170 °C for 1 h and then loaded into the reactor. 2 Heat to 650℃ and keep it stable, then introduce CH 4 After carbonization for 2 hours, the catalyst was heated to 800°C and the catalyst performance was evaluated at a space velocity of 3 L / (g·h) and atmospheric pressure. The reaction gas was methane and the reaction time was 120 minutes. The methane conversion rate, the formation rate and selectivity of hydrocarbon products were analyzed by Shimadzu GC-2014C gas chromatography.

[0030] Comparative Example 3

[0031] The catalytic reaction activity experiment of SAPO-34 catalyst powder in a fixed fluidized bed microreactor evaluation device showed that the reaction conditions were a loading of 5 g and a space velocity of 4 h -1The catalytic reaction of methanol to olefins was carried out under the conditions of reaction temperature of 480℃ and reaction pressure of 0.1MPa. SP3420 gas chromatograph was used for analysis. The chromatographic column was an Agile ent HP-PLOT / QO4 capillary column of 0.53mm×30m×40μm, the carrier gas was nitrogen, and the detector was FID. The conversion rate of methanol and the selectivity of olefins were analyzed.

[0032] Comparative Example 4

[0033] Cyclohexanone was added at once, and hydrogen peroxide and ammonia were added continuously. 1.5g TS-1 catalyst powder, 15.2g cyclohexanone, 15.0g deionized water, 30.0g tert-butyl alcohol, 24.0g hydrogen peroxide (30%), 22.9g ammonia (25%), reaction temperature 75°C, reaction time 5h. Agilent 6820 gas chromatograph was used to analyze the mass fraction of cyclohexanone and cyclohexanone oxime in the reactants.

[0034] Embodiment 1

[0035] The first step is to premix the catalyst slurry by ultra-gravity

[0036] According to the mass ratio of silica in silica sol: titanium silicon molecular sieve catalyst of 1:0.5, silica sol and molecular sieve catalyst are preliminarily premixed into slurry. The premixed slurry enters the supergravity device through peristalsis for circulation, and a uniform molecular sieve catalyst slurry is obtained according to the supergravity device speed of 10HZ and the supergravity strengthening time of 2h.

[0037] The second step is the spraying of catalyst slurry

[0038] The slurry obtained in the first step was spray-formed at a feed rate of 15 mL / min and a supergravity spray rotating disk speed of 250 Hz, and then calcined at a high temperature to obtain titanium silicon molecular sieve catalyst microspheres.

[0039] The titanium silicon molecular sieve catalyst microsphere catalyst is used for the catalytic oxidation of butanone to butanone oxime reaction of butanone, the catalyst, tert-butyl alcohol and butanone are evenly mixed in a three-necked flask, the temperature is raised and maintained at 70°C, and then a hydrogen peroxide solution and an ammonia solution are added to the three-necked flask at a speed of 1.0 mL / min by a micro-feed pump, and the reaction is continued at a constant temperature for 35 minutes after the hydrogen peroxide and ammonia solutions are added, and the reaction ends. The reaction product is analyzed by a gas chromatograph (Sh imadzu14B, F ID), and the conversion rate of butanone and the selectivity of butanone oxime are calculated by the area normalization method.

[0040] Embodiment 2

[0041] The first step is to premix the catalyst slurry by ultra-gravity

[0042] According to the mass ratio of silica in silica sol: ZSM-5 molecular sieve catalyst of 1:0.25, silica sol and molecular sieve catalyst were pre-mixed into slurry. The pre-mixed slurry was circulated into the supergravity device by peristalsis, and a uniform molecular sieve catalyst slurry was obtained according to the supergravity device speed of 15HZ and the supergravity strengthening time of 1.5h.

[0043] The second step is the spraying of catalyst slurry

[0044] The slurry obtained in the first step was spray-formed at a feed rate of 35 mL / min and a supergravity spray rotating disk speed of 250 Hz, and then calcined at a high temperature to obtain ZSM-5 molecular sieve catalyst microspheres.

[0045] 32 g of ZSM-5 molecular sieve catalyst microspheres were dried at 170 °C for 1 h and loaded into the reactor. 2 The catalyst was heated to 650°C and kept stable, then CH4 was introduced for carbonization for 2 hours, and finally the catalyst was heated to 800°C. The catalyst performance was evaluated at a space velocity of 3L / (g·h) and atmospheric pressure. The reaction gas was methane and the reaction time was 120min. The methane conversion rate, the formation rate and selectivity of hydrocarbon products were analyzed using a Shimadzu GC-2014C gas chromatograph.

[0046] Embodiment 3

[0047] The first step is to premix the catalyst slurry by ultra-gravity

[0048] According to the mass ratio of silica in silica sol: SAPO-34 molecular sieve catalyst of 1:0.35, silica sol and molecular sieve catalyst were preliminarily premixed into slurry. The premixed slurry was circulated into the supergravity device by peristalsis, and a uniform molecular sieve catalyst slurry was obtained according to the supergravity device speed of 30HZ and the supergravity strengthening time of 2h.

[0049] The second step is the spraying of catalyst slurry

[0050] The slurry obtained in the first step was spray-formed at a feed rate of 30 mL / min and a supergravity spray rotating disk speed of 230 Hz, and then calcined at a high temperature to obtain SAPO-34 molecular sieve catalyst microspheres.

[0051] The catalytic reaction activity experiment of SAPO-34 molecular sieve catalyst microspheres in a fixed fluidized bed microreactor evaluation device showed that the reaction conditions were a loading of 5 g and a space velocity of 4 h -1The catalytic reaction of methanol to olefins was carried out under the conditions of reaction temperature of 480℃ and reaction pressure of 0.1MPa. SP3420 gas chromatograph was used for analysis. The chromatographic column was an Agilent HP-PLOT / QO4 capillary column of 0.53mm×30m×40μm. The carrier gas was nitrogen and the detector was FID. The conversion rate of methanol and the selectivity of olefins were analyzed.

[0052] Embodiment 4

[0053] The first step is to premix the catalyst slurry by ultra-gravity

[0054] According to the mass ratio of silica in silica sol: TS-1 molecular sieve catalyst of 1:0.4, silica sol and molecular sieve catalyst were preliminarily premixed into slurry. The premixed slurry was circulated into the supergravity device by peristalsis, and a uniform molecular sieve catalyst slurry was obtained according to the supergravity device speed of 50HZ and the supergravity strengthening time of 4h.

[0055] The second step is the spraying of catalyst slurry

[0056] The slurry obtained in the first step was spray-formed at a feed rate of 20 mL / min and a supergravity spray rotating disk speed of 250 Hz, and then calcined at a high temperature to obtain TS-1 molecular sieve catalyst microspheres.

[0057] Cyclohexanone was added at once, and hydrogen peroxide and ammonia were added continuously. TS-1 molecular sieve catalyst microspheres 1.5g, cyclohexanone 15.2g, deionized water 15.0g, tert-butyl alcohol 30.0g, hydrogen peroxide (30%) 24.0g. Ammonia (25%) 22.9g, reaction temperature 75℃, reaction time 5h. Agilent 6820 gas chromatograph was used to analyze the mass fraction of cyclohexanone and cyclohexanone oxime in the reactants.

[0058] Embodiment 5

[0059] The first step is to premix the catalyst slurry by ultra-gravity

[0060] According to the mass ratio of silica in silica sol to titanium silicon molecular sieve catalyst of 1:0.5, silica sol and molecular sieve catalyst are preliminarily premixed into slurry. The premixed slurry enters the supergravity device through peristalsis for circulation, and a uniform molecular sieve catalyst slurry is obtained according to the supergravity device speed of 30HZ and the supergravity strengthening time of 3h.

[0061] The second step is the spraying of catalyst slurry

[0062] The slurry obtained in the first step was spray-formed at a feed rate of 10 mL / min and a supergravity spray rotating disk speed of 220 Hz, and then calcined at a high temperature to obtain molecular sieve catalyst microspheres.

[0063] The titanium silicon molecular sieve catalyst microsphere catalyst is used for the catalytic oxidation of butanone to butanone oxime reaction of butanone, the catalyst, tert-butyl alcohol and butanone are evenly mixed in a three-necked flask, the temperature is raised and maintained at 70°C, and then a hydrogen peroxide solution and an ammonia solution are added to the three-necked flask at a speed of 1.0 mL / min by a micro-feed pump, and the reaction is continued at a constant temperature for 35 minutes after the hydrogen peroxide and ammonia solutions are added, and the reaction ends. The reaction product is analyzed by a gas chromatograph (Sh imadzu14B, F ID), and the conversion rate of butanone and the selectivity of butanone oxime are calculated by the area normalization method.

[0064] Table 1

[0065] catalyst Raw material conversion rate / % Selectivity of target product / % Comparative Example 1 99 99 Comparative Example 2 68 17 Comparative Example 3 100 85 Comparative Example 4 99 99 Embodiment 1 98 98 Embodiment 2 67 15 Embodiment 3 99 83 Embodiment 4 98 98 Embodiment 5 99 99

[0066] From the evaluation results in Table 1, it can be seen that by comparing the evaluation data of the catalyst original powder, it is found that the catalytic activity of the catalyst microspheres obtained by spray molding using ultra-gravity technology is basically the same as the activity of the catalyst original powder, the catalytic performance has not been greatly reduced, and the catalyst microspheres have good stability.

[0067] from Figure 1-5 It can be seen that after the slurry is premixed under ultra-gravity, the original powder is dispersed more evenly and the ball formation rate is further improved. Under conventional kettle mechanical stirring, the morphology of the catalyst microspheres remains unchanged.

[0068] The embodiments of the present application are described above in conjunction with the accompanying drawings. In the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A method for preparing catalyst microspheres by ultra-gravity method, characterized in that , including the following steps: The first step is to premix the catalyst slurry under ultra-gravity: After the silica sol containing silicon dioxide and the catalyst are preliminarily mixed into a slurry according to a certain proportion, the mixed slurry is pumped into an ultra-gravity device by a peristaltic pump for enhanced mixing to obtain a uniform catalyst slurry; The second step is the spray molding of the catalyst slurry: the catalyst slurry obtained in the first step is spray-molded by an ultra-gravity machine, and then calcined at high temperature to obtain catalyst microspheres.

2. The method for preparing catalyst microspheres under high gravity according to claim 1, characterized in that: The type of catalyst is one or more of titanium silicon molecular sieve catalyst, ZSM-5 molecular sieve catalyst, SAPO-34 molecular sieve catalyst and TS-1 molecular sieve catalyst.

3. The method for preparing catalyst microspheres under high gravity according to claim 1, characterized in that: The silica sol containing silicon dioxide and the catalyst are mixed in a ratio of silicon dioxide to catalyst of 1:0.05-0.8 by mass.

4. The method for preparing catalyst microspheres under high gravity according to claim 1, characterized in that: The rotation speed of the ultra-gravity device is 10-60HZ, and the ultra-gravity enhanced mixing time is 0.5-5h.

5. The method for preparing catalyst microspheres under high gravity according to claim 1, characterized in that: The feed rate of the spray forming is 10-300 mL / min, and the rotation speed of the ultra-gravity spray rotary nozzle of the spray forming is 200-300 Hz.

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