A tabletop continuous flow reaction system and a preparation method of micro-nano materials

Abstract

The present invention provides a tabletop continuous flow reaction system and a preparation method of micro-nano materials. The reaction system includes a core reactor and a process intensification reactor. The core reactor includes a first liquid inlet, a second liquid inlet, a first liquid distribution module, a second liquid distribution module and a mixing chamber. The first liquid inlet is connected to the inlet of the first liquid distribution module, and the second liquid inlet is connected to the inlet of the second liquid distribution module. The first liquid distribution module includes a plurality of first liquid distribution channels, and the second liquid distribution module includes at least two layers of spiral-shaped second liquid distribution channels. The first liquid distribution channels are located between adjacent spiral lines of the second liquid distribution channels. The mixing chamber is located at the outlets of the first liquid distribution module and the second liquid distribution module. The process intensification reactor includes an ultrasonic tank and an ultrasonic reaction pipe placed in the ultrasonic tank. The technical solution of the present invention effectively realizes the spatial separation of mass transfer mixing and rapid reaction, which is beneficial to preparing nano-powders with good stability and consistency.

Description

Technical Field

[0001] The present invention relates to the technical field of continuous flow reaction, and particularly to a tabletop continuous flow reaction system and a preparation method of micro-nano materials. Background Art

[0002] In a solution system, the wet chemical method for synthesizing and preparing materials by chemical reaction is one of the main means and ways to obtain various new materials. The wet chemical method has many advantages such as mature equipment, convenient operation, easy control of composition, mild conditions, high efficiency, large output, etc., and has become a widely used new material synthesis and preparation method in current laboratories and industrial production.

[0003] Common equipment for synthesizing and preparing materials by wet chemical method in laboratories generally uses small-volume flasks, beakers, etc. With the increase in production, the volume of the reaction vessel is gradually enlarged until large-volume reaction kettles are used in industrial production to achieve large-scale synthesis and preparation of materials. Since the efficiency of momentum transfer, heat transfer, and mass transfer of the reaction materials changes greatly with the increase in the volume of the reaction vessel, the chemical reaction kinetic conditions for synthesizing and preparing materials also change greatly accordingly, and the morphology, size and size distribution, crystallinity, yield, etc. of the synthesized and prepared materials will all change significantly. This magnification effect caused by the increase in the volume of the reaction vessel will seriously affect the industrialization transformation process and transformation success rate of the wet chemical method for synthesizing and preparing materials.

[0004] In recent years, the continuous flow reaction technology represented by microchannel reactors has been widely used in industries such as pharmaceuticals, fine chemicals, petrochemicals, and materials due to its many advantages such as small on-line reaction liquid holdup, high mass and heat transfer efficiency, precise parameter control, stable process, small magnification effect, safety and high efficiency. Since the channel size of the microchannel reactor is very small, usually in the micrometer range, the resistance of the material flowing in the microchannel is very large. For fast reactions with a large increase in viscosity during the reaction process, or reactions involving or generating solid particles, it is extremely easy to cause blockage of the microchannel and make the microchannel reactor ineffective. Especially for small microchannel reactors used in laboratory research, this blockage phenomenon caused by a large increase in viscosity and the presence of solid particles is more serious.

[0005] In summary, for fast reactions with an increase in viscosity and the presence of solid particles during the reaction process, especially for such reactions as wet chemical fast reactions to generate micro-nano solid particles, this continuous flow reaction technology based on microchannel reactors is severely limited in the application of preparing micro-nano powder materials due to the serious microchannel blockage phenomenon. Summary of the Invention

[0006] In view of the above technical problems, the present invention discloses a tabletop continuous flow reaction system and a method for preparing micro-nano materials, which can effectively solve the blockage problem of microchannel reactors and are particularly suitable for rapid reactions with increased viscosity or the presence of solid particles during the reaction process.

[0007] For this, the technical solution adopted by the present invention is as follows:

[0008] A tabletop continuous flow reaction system includes a core reactor and a process intensification reactor. The core reactor includes a first liquid inlet, a second liquid inlet, a first liquid distribution module, a second liquid distribution module, and a mixing chamber. The first liquid inlet is connected to the inlet of the first liquid distribution module, the second liquid inlet is connected to the inlet of the second liquid distribution module. The first liquid distribution module includes a number of first liquid distribution channels, the second liquid distribution module includes at least two layers of spiral-shaped second liquid distribution channels, and the first liquid distribution channels are located between adjacent spirals of the second liquid distribution channels;

[0009] The mixing chamber is located at the outlets of the first liquid distribution module and the second liquid distribution module;

[0010] The process intensification reactor includes an ultrasonic tank and an ultrasonic reaction pipe placed in the ultrasonic tank. The outlet of the mixing chamber is connected to the inlet of the ultrasonic reaction pipe.

[0011] Adopting this technical solution, the core reactor is used to divide the single liquid flow of the first reaction liquid transported to the first liquid distribution module into multiple tributaries, and form a spiral annular tributary with the second reaction liquid passing through the second liquid distribution module to achieve the spaced arrangement of different solution tributaries. It presents that the tributaries of the first reaction liquid are wrapped by the annular second reaction liquid, and then synchronously flow into the mixing chamber. The annular second reaction liquid flows along the inner wall of the mixing chamber, and the first reaction liquid is wrapped in the second reaction liquid. In this way, micro-mixing will occur at the contact interface of the two reaction liquids. At the same time, since only the second reaction liquid flows along the inner wall of the mixing chamber and no solid particles are generated, the phenomenon of solid particle adhesion and pipeline blockage is fundamentally avoided. The two reaction liquids are preliminarily mixed in the mixing chamber and discharged from the liquid outlet, and flow into the process intensification reactor. The preliminarily mixed solution flowing in the ultrasonic reaction pipe rapidly realizes atomic-level mass transfer mixing and rapid reaction to generate micro-nano particles under the strong mechanical micro-perturbation action of ultrasonic waves. At the same time, the strong cavitation effect of ultrasonic waves can also effectively avoid the agglomeration of solid particles and prevent the blockage of the reaction pipeline.

[0012] As a further improvement of the present invention, the number of the first liquid distribution channels is arranged in a ring shape.

[0013] As a further improvement of the present invention, the second liquid distribution channels are arranged in an arc spiral shape or a polygonal spiral shape.

[0014] As a further improvement of the present invention, the liquid inlet directions of the first liquid inlet and the second liquid inlet are perpendicular to each other.

[0015] As a further improvement of the present invention, the ultrasonic reaction pipeline is a spiral pipe.

[0016] As a further improvement of the present invention, the tabletop continuous flow reaction system includes a circulating water system and a constant temperature water bath. The circulating water system is connected to the constant temperature water bath, and the circulating water system is connected to the core reactor and the process intensification reactor to control the temperatures of the core reactor and the process intensification reactor.

[0017] As a further improvement of the present invention, the tabletop continuous flow reaction system includes a central controller. A number of temperature sensors are provided on the core reactor and the process intensification reactor, and a temperature sensor is provided on the constant temperature water bath. The temperature sensors communicate with the central controller to display the temperatures at each temperature measurement point.

[0018] As a further improvement of the present invention, the first liquid inlet is connected to a first conveying system, and the second liquid inlet is connected to a second conveying system. The first conveying system and the second conveying system respectively control the flow rates of the reaction liquids entering the first liquid inlet and the second liquid inlet, so that the flow rate difference between the two reaction liquids is 10 - 200%. With this technical solution, the flow rate difference between the two reaction liquids is controlled within 10 - 200%, so that micro-mixing caused by the flow rate difference will occur at the contact interface of the two reaction liquids, better realizing primary micro-mixing and micro-reaction, and no large-particle substances will be generated, avoiding pipeline blockage.

[0019] As a further improvement of the present invention, both the first conveying system and the second conveying system include a plunger pump and a connecting pipeline. A ball valve, a pressure gauge and a needle valve are provided on the connecting pipeline.

[0020] As a further improvement of the present invention, the outlet of the ultrasonic reaction pipeline is connected to an aging reactor through a pipeline. The aging reactor is a double-layer reaction kettle with a stirrer, and an ultrasonic horn is provided in the reaction kettle. Circulating water is introduced into the interlayer of the double-layer reaction kettle to cooperate with the constant temperature water bath to achieve temperature control. With this technical solution, the solution that is rapidly mixed and reacted in the core reactor and the process intensification reactor flows into the aging reactor, and further reacts completely at the set temperature, ultrasonic power and stirring speed, and then the required micro-nano powder particles can be prepared.

[0021] As a further improvement of the present invention, the tabletop continuous flow reaction system includes a solution metering system. The solution metering system includes 2 sets of electronic scales and a double-layer liquid storage barrel placed on the electronic scales. The jacket of the double-layer storage barrel is evacuated, having good heat insulation and heat preservation functions. Among them, the two liquid storage barrels are respectively connected to the first conveying system and the second conveying system.

[0022] Furthermore, the weighing value of the electronic scale is transmitted to the central controller through a data cable and displayed on the display screen. The prepared reactant solution is placed in the storage bucket. The measuring range of the electronic scale is 200 - 20000g, and the accuracy is 0.01 - 0.1g.

[0023] The present invention also discloses a preparation method of micro - nano materials, which is prepared by using the continuous - flow preparation device for micro - nano powder materials as described above, and includes the following steps:

[0024] Step S1: Two reaction solutions are respectively transported to the first liquid inlet and the second liquid inlet of the core reactor. One reaction solution is divided into several branches through the first liquid - separation module and mixed with the annular branches formed by the other reaction solution passing through the second liquid - separation module, and then enters the mixing chamber to obtain a mixed solution;

[0025] Step S2: The mixed solution enters the process - intensifying reactor and rapidly reacts to generate micro - nano particles under the conditions of a constant - temperature water bath and the action of ultrasonic waves;

[0026] Step S3: The mixture in the process - intensifying reactor enters the aging reactor. Circulating water is introduced into the interlayer of the double - layer reaction kettle, and further reaction occurs under the action of a stirrer and an ultrasonic horn. After filtration, washing, and drying, micro - nano powder is obtained.

[0027] As a further improvement of the present invention, in step S1, the transportation pressure is 0.15 - 1.2 Mpa, and the flow - rate difference between the two reaction solutions is 10 - 200%;

[0028] In step S2, the frequency of the ultrasonic wave is 20 - 100 KHz, and the power density of the ultrasonic wave is 0.5 - 5 W / cm 2 ;

[0029] In step S3, the frequency of the ultrasonic horn is 20 - 100 KHz, the power density is 0.8 - 10 W / cm 2 , the rotation speed of the stirrer is 80 - 600 rpm, and the temperature of the circulating water is - 20 - 90 °C.

[0030] As a further improvement of the present invention, the volume of the reaction kettle is 0.5 - 5 L.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] First, the technical solution of the present invention utilizes the combination of a core reactor and a process intensification reactor. In the core reactor, the diversion, spaced arrangement, and preliminary mixing of two reaction liquids are realized respectively. In the process intensification reactor, the atomic-level mixing of the two reaction liquids and the generation of nanoparticles are rapidly achieved. The spatial separation of mass transfer mixing and rapid reaction is effectively realized, which not only meets the rapid mass transfer requirements for rapid reaction but also realizes continuous reaction operation, facilitating the preparation of nano-powders with good stability and consistency. This technical solution can completely avoid the problem of coexistence of multiple phenomena (new crystal nucleus generation, growth of existing crystal nuclei, nanoparticle agglomeration, etc.) in the physical space of a single reaction kettle due to the mismatch between mass transfer rate and reaction rate, thus completely avoiding the problems of large particle size, wide size distribution, irregular morphology, and serious agglomeration in the preparation of nano-materials using a single reaction kettle.

[0033] Second, the technical solution of the present invention comprehensively utilizes the diversion of the core reactor to achieve the spaced arrangement of multiple branches of the two reaction liquids, increasing the contact area between the two reaction liquids. Further, a flow rate difference between the two reaction liquids can be created, and the preliminary mixing of the two reaction liquids is realized using the flow rate difference, further greatly shortening the mass transfer distance between the two reaction liquids and laying a foundation for the rapid realization of atomic-level uniform mixing by ultrasonic perturbation in the next step.

[0034] Third, the technical solution of the present invention comprehensively utilizes the diversion arrangement of the core reactor and the ultrasonic action of the process intensification reactor to completely avoid the problem of reaction pipeline blockage. The two liquids entering the core reactor flow through different channels respectively before flowing out from the diversion disk and do not come into contact, so there is no problem of solid particle generation and pipeline blockage. The two liquids flowing into the mixing chamber pipeline from the spaced arrangement of the diversion disk are preliminarily mixed under the perturbation of the flow rate difference. Even if solid particles are generated, they are wrapped in the fluid far from the inner wall of the pipeline, and only one liquid always contacts the inner wall of the mixing chamber pipeline, and there is no phenomenon of solid particle generation and pipeline blockage. By comprehensively adopting the method of spatial separation (liquid separation disk, mixing chamber, and process intensification reactor) and time continuity, the problem of amplification effect caused by the mismatch between the three transfer rates and the reaction rate is solved by relying on spatial separation, and the large-scale macro-quantity preparation of micro-nano powders is realized through time continuous accumulation. Moreover, it is not large in volume, can be placed on the table, and is convenient to use. Brief Description of the Drawings

[0035] Figure 1 is a schematic structural diagram of a tabletop continuous flow reaction system according to Embodiment 1 of the present invention.

[0036] Figure 2 is a schematic structural diagram of the core reactor according to Embodiment 1 of the present invention.

[0037] Figure 3It is the assembly drawing of the core reactor in Embodiment 1 of the present invention.

[0038] Figure 4 It is the schematic cross-sectional view of the assembled core reactor in Embodiment 1 of the present invention.

[0039] Figure 5 It is the distribution diagram of the liquid separation flow of the core reactor in Embodiment 1 of the present invention.

[0040] Figure 6 It is the morphology diagram of the high-purity silica sol particles prepared in Embodiment 2 of the present invention, and the inset in the figure is the size distribution diagram.

[0041] Figure 7 It is the SEM image of the nano manganese iron phosphate prepared in Embodiment 2 of the present invention.

[0042] Figure 8 It is the SEM image of the nano ternary precursor prepared in Embodiment 2 of the present invention.

[0043] Figure 9 It is the SEM image of the nano nickel particles prepared in Embodiment 2 of the present invention.

[0044] Reference numerals include:

[0045] 1 - First reaction liquid, 2 - Second reaction liquid, 3 - Core reactor, 4 - Process intensification reactor, 5 - Aging reactor, 6 - Circulating water system, 7 - Constant temperature water bath;

[0046] 31 - First liquid inlet, 32 - Second liquid inlet, 33 - First liquid separation module, 34 - Second liquid separation module, 35 - Mixing chamber, 36 - First liquid separation channel, 37 - Second liquid separation channel. Detailed implementation manners

[0047] The following further details the preferred embodiments of the present invention.

[0048] Embodiment 1

[0049] As Figure 1 shown, a tabletop continuous flow reaction system includes a precision delivery system, a pressure control system, a temperature control system, a core reactor 3, a process intensification reactor 4, and a central control system. The process intensification reactor 4 is connected to an aging reactor 5 through a connecting pipe, and the precision delivery system is connected to a solution metering system through a pipeline.

[0050] The solution metering system consists of two sets of electronic scales and a double-layer liquid storage tank placed on the electronic scales. The jacket of the double-layer liquid storage tank is evacuated, with good heat insulation and heat preservation functions. The weighing values of the electronic scales are transmitted to the central control system via data lines and displayed on the display screen. The prepared reactant solution is placed in the liquid storage tank. The measuring range of the electronic scales is 200 - 20000 g, and the accuracy is 0.01 - 0.1 g.

[0051] The precision conveying system consists of two high-precision plunger pumps and connecting pipes, and is used to convey the reaction solution to the core reactor 3 with constant flow and constant pressure. The flow range of the high-precision plunger pumps is 10 - 200 ml / min, and the accuracy is ±0.01%.

[0052] The pressure control system consists of a ball valve, a pressure gauge and a needle valve. The pressure gauge is used to measure and display the liquid pressure in the conveying pipeline. The ball valve is used to roughly adjust the liquid pressure in the conveying pipeline, and the needle valve is used to finely adjust the liquid pressure in the conveying pipeline. The liquid pressure range in the conveying pipeline is 0.15 - 1.2 MPa.

[0053] The temperature control system consists of a circulating water system 6 and multiple temperature measuring thermocouples, and is used to control the temperatures of the core reactor 3 and the process intensification reactor 4. At the same time, 4 - 12 temperature measuring points are provided on the core reactor 3 and the process intensification reactor 4. Together with the temperature of the circulating water tank, they are connected via data lines and displayed on the display screen of the central control system. The circulating water system 6 is connected to the constant temperature water tank 7. The temperature control range of the constant temperature water tank 7 is -20 - 90 °C, and the temperature control accuracy is ±0.5 °C.

[0054] Such as Figures 2 to 5As shown in the figure, the core reactor 3 is used to divide a single liquid flow transported by the precision delivery system into multiple branch flows and achieve the spaced arrangement of different solution branch flows. The core reactor 3 includes a first liquid inlet 31, a second liquid inlet 32, a first liquid separation module 33, a second liquid separation module 34, and a mixing chamber 35. The first liquid inlet 31 is connected to the delivery system of the first reaction liquid 1, and the second liquid inlet 32 is connected to the delivery system of the second reaction liquid 2. The first liquid inlet 31 is connected to the inlet of the first liquid separation module 33, and the second liquid inlet 32 is connected to the inlet of the second liquid separation module 34. The first liquid separation module 33 includes a number of first liquid separation channels 36, and the number of first liquid separation channels 36 is arranged in a ring shape. The second liquid separation module 34 includes at least two layers of spiral second liquid separation channels 37, and the first liquid separation channels 36 are located between adjacent spirals of the second liquid separation channels 37; further, the second liquid separation channels 37 are arranged in an arc spiral or a polygonal spiral. The mixing chamber 35 is located at the outlets of the first liquid separation module 33 and the second liquid separation module 34. The two reaction liquids enter the core reactor 3 vertically from the first liquid inlet 31 and the second liquid inlet 32 respectively. The first reaction liquid 1 enters the core reactor 3 from the first liquid inlet 31 and is divided into multiple branch flows by the first liquid separation module 33 (only three branch flows are shown in the figure, and actually there can be more branch flows, such as more and finer branch flows like a shower head), and the number of the multiple branch flows is 3 to 100. The second reaction liquid 2 enters the core reactor 3 vertically from the second liquid inlet 32 and forms a spiral annular branch flow after passing through the second liquid separation module 34, so as to achieve the spaced arrangement of the first reaction liquid 1 and the second reaction liquid 2, presenting that multiple branch flows of the first reaction liquid 1 are wrapped by the annular second reaction liquid 2 (see Figure 5 ). After the first reaction liquid 1 and the second reaction liquid 2 are split by the first liquid separation module 33 and the second liquid separation module 34, they flow synchronously into the pipeline of the mixing chamber 35. The annular second reaction liquid 2 flows along the inner wall of the pipeline, and the first reaction liquid 1 is wrapped in the second reaction liquid 2. The purpose of splitting into branches here is to increase the contact area between the two liquids and shorten the mass transfer distance of mixing. Further, the flow rate difference between the two reaction liquids is controlled within 10% to 200%, so that there is a preliminary and smaller micro-mixing at the contact interface of the two reaction liquids. At the same time, since only the second reaction liquid 2 flows along the inner wall of the pipeline and no solid particles are generated, the occurrence of the phenomenon of solid particle adhesion and pipeline blockage is fundamentally avoided. The two reaction liquids are preliminarily mixed in the mixing chamber 35 and then discharged from the liquid outlet.

[0055] The process intensification reactor 4 includes an ultrasonic tank and an ultrasonic reaction pipeline placed in the ultrasonic tank. The outlet of the mixing chamber 35 is connected to the inlet of the ultrasonic reaction pipeline. The ultrasonic reaction pipeline is a spiral pipe.

[0056] The aging reactor 5 is a double-layer glass reactor with a stirrer. An ultrasonic horn is inserted into the reactor, and circulating water is introduced into the glass interlayer to cooperate with the constant temperature water bath 7 to achieve temperature control. The solution that has undergone rapid mixing reaction in the core process intensification reactor 4 flows into the aging reactor 5, and further reacts completely under the set temperature, ultrasonic power, and stirring speed to obtain the required micro-nano powder particles. The frequency of the ultrasonic wave is 20 - 100 KHz, and the power density of the ultrasonic wave is 0.8 - 10 W / cm 2 , the volume of the glass reactor is 0.5 - 5 L, the stirring speed is 80 - 600 rpm, the temperature control range of the constant temperature water bath 7 is -20 - 90 °C, and the temperature control accuracy is ±0.5 °C.

[0057] The central control system is the control center of the entire reaction system. Parameters such as the solution metering system, precise conveying system, pressure control system, temperature control system, pipeline pressure, temperature at various positions of the system, and ultrasonic power are connected to the central control system through data lines, displayed on the display screen of the central control system, and these process parameters can be changed by inputting the set values of each parameter on the display screen. The process parameters of each reaction operation are recorded in the central control system and can be accessed at any time or imported into a computer.

[0058] When using the above bench-top continuous flow reaction system wet chemical method to prepare micro-nano powder materials, it includes the following steps:

[0059] Step S1, the reaction solutions prepared by dissolving the reactants and heating them to the set temperature are respectively poured into the double-layer storage barrels of the solution metering system, and the storage barrel lids connected with the conveying pipelines are covered.

[0060] Step S2, turn on the solution metering system, continuous flow reaction system, and process intensification reactor. Input the set values of parameters such as flow rate, pressure, temperature, and ultrasonic power density required for the reaction in the central control system, and set parameters such as the temperature, ultrasonic power density, and stirring speed of the aging reactor. Turn on the temperature control system to make the core reactor, process intensification reactor, and aging reactor reach the set temperature value. Turn on the electronic scale to make the displayed value of the electronic scale zero.

[0061] Step S3, turn on the central control system, start the high-precision plunger pump and the ultrasonic generator of the process intensification reactor. At the same time, adjust the ball valve and needle valve to make the liquid pressure in the conveying pipeline reach the set value, so that the two reaction solutions flow into the process intensification reactor in a constant pressure and constant flow manner through the core reactor in a shunted and spaced arrangement, and quickly react to generate micro-nano solid particles under the cavitation effects such as ultrasonic enhanced mass transfer, reaction, and crystallization.

[0062] Step S4: Turn on the stirrer and ultrasonic generator of the aging reactor. The suspension obtained from the continuous flow reaction system flows into the glass reaction kettle and continues to react for a period of time under the set temperature, ultrasonic power, and stirring speed. The prepared micro-nano particles are then filtered, washed, and dried to obtain micro-nano powder.

[0063] The following will be described in conjunction with specific embodiments.

[0064] Example 2

[0065] Use the tabletop continuous flow reaction system of Example 1 to prepare high-purity silica sol. The steps are as follows:

[0066] Step S1: Mix absolute ethanol and tetraethyl orthosilicate in a volume ratio of 3.5:1 to prepare the first reaction solution. Mix absolute ethanol, 25% ammonia water, and pure water in a volume ratio of 21.3:1.3:1 to prepare the second reaction solution. Heat both the first reaction solution and the second reaction solution to 30°C, and pour them into two double-layer storage barrels of the solution metering system respectively. Cover the storage barrel lids connected with the conveying pipelines. Place the two storage barrels on two electronic scales respectively, and zero the display values of the electronic scales.

[0067] Step S2: Turn on the solution metering system, continuous flow reaction system, and process intensification reactor. Input the set values of parameters required for the reaction (the flow rate of the first reaction solution is 50 ml / min, and the flow rate of the second reaction solution is 65 ml / min), pressure 0.5 MPa, temperature 30°C, ultrasonic power density 2.5 W / cm 2 and other parameter set values in the central control system. Set the temperature of the aging reactor to 30°C, ultrasonic power density 6.0 W / cm 2 , stirring speed 275 rpm and other parameters. Turn on the temperature control system to make the core reactor, process intensification reactor, and aging reactor reach the set temperature values.

[0068] Step S3: Turn on the central control system, start the high-precision plunger pump and the ultrasonic generator of the process intensification reactor. At the same time, adjust the ball valve and needle valve to make the liquid pressures of the two conveying pipelines reach the set value of 0.5 MPa, so that the two reaction solutions flow into the process intensification reactor in a constant pressure and constant flow manner through the core reactor in a shunted and spaced arrangement, and quickly react to generate micro-nano solid particles under the cavitation effects of ultrasonic enhanced mass transfer, reaction, crystallization, etc.

[0069] Step S4: Turn on the stirrer and ultrasonic generator of the aging reactor. The suspension obtained from the continuous flow reaction system flows into the glass reaction kettle and continues to react for 1.5 hours under the set temperature, ultrasonic power, and stirring speed to obtain high-purity silica sol. The morphology, size, size distribution, etc. of the silicon dioxide nano-particles therein are as Figure 6As shown, it can be seen that the obtained silica nanoparticles have uniform size and good consistency.

[0070] Example 3

[0071] The nano manganese iron phosphate is prepared by using the bench-top continuous flow reaction system of Example 1. The steps are as follows:

[0072] Step S1: Dissolve ammonium dihydrogen phosphate in pure water to prepare a first reaction solution with a concentration of 1.2 mol / L. Dissolve manganese sulfate and ferric sulfate in pure water to prepare a second reaction solution with a manganese sulfate concentration of 0.6 mol / L and a ferric sulfate concentration of 0.4 mol / L. Heat both the first reaction solution and the second reaction solution to 50 °C, and pour them into two double-layer storage barrels of the solution metering system respectively. Cover the storage barrel lids connected with the conveying pipelines. Place the two storage barrels on two electronic scales respectively to zero the display values of the electronic scales.

[0073] Step S2: Turn on the solution metering system, the continuous flow reaction system and the process intensification reactor. Input the required flow rate (the flow rate of the first reaction solution is 100 ml / min, and the flow rate of the second reaction solution is 140 ml / min), pressure of 0.8 MPa, temperature of 50 °C, ultrasonic power density of 4.0 W / cm 2 and other parameter setting values in the central control system. Set the temperature of the aging reactor to 50 °C, ultrasonic power density to 8.0 W / cm 2 , stirring speed to 350 rpm and other parameters. Turn on the temperature control system to make the core reactor, the process intensification reactor and the aging reactor reach the set temperature values.

[0074] Step S3: Turn on the central control system, start the high-precision plunger pump and the ultrasonic generator of the process intensification reactor. At the same time, adjust the ball valve and needle valve to make the liquid pressures of the two conveying pipelines reach the set value of 0.8 MPa, so that the two reaction solutions flow into the process intensification reactor through the core reactor in a constant pressure and constant flow manner and are arranged at intervals. Under the cavitation effects of ultrasonic enhanced mass transfer, reaction, crystallization, etc., they react rapidly to generate micro-nano solid particles.

[0075] Step S4: Turn on the stirrer and ultrasonic generator of the aging reactor. The suspension obtained from the continuous flow reaction system flows into the glass reaction kettle and continues to react for 2.0 hours at the set temperature, ultrasonic power and stirring speed to obtain nano manganese iron phosphate particles. Then, after filtration, washing and drying, manganese iron phosphate powder is obtained. The scanning electron microscope photo of the prepared nano manganese iron phosphate is as Figure 7 shown.

[0076] Example 4

[0077] The ternary precursor is prepared by using the bench-top continuous flow reaction system of Example 1. The steps are as follows:

[0078] Step S1: Dissolve sodium hydroxide and ammonia water in pure water to prepare a first reaction solution with a sodium hydroxide concentration of 4.0 mol / L and an ammonia water concentration of 1.05 mol / L. Dissolve it in pure water according to the molar ratio of NiSO4:CoSO4:MnSO4 = 6:2:2 to prepare a second reaction solution with a metal salt concentration of 1.5 mol / L. Heat both the first reaction solution and the second reaction solution to 55°C, and pour them into 2 double-layer storage barrels of the solution metering system respectively. Cover the storage barrel lids connected with the conveying pipelines. Place the 2 storage barrels on 2 electronic scales respectively, and zero the display values of the electronic scales.

[0079] Step S2: Turn on the solution metering system, the continuous flow reaction system and the process intensification reactor. Input the set values of parameters required for the reaction (the flow rate of the first reaction solution is 150 ml / min, and the flow rate of the second reaction solution is 200 ml / min), pressure 1.0 MPa, temperature 55°C, ultrasonic power density 3.2 W / cm 2 in the central control system, and set the temperature of the aging reactor to 55°C, ultrasonic power density 6.0 W / cm 2 , stirring speed 250 rpm and other parameters. Turn on the temperature control system to make the core reactor, the process intensification reactor and the aging reactor reach the set temperature values.

[0080] Step S3: Turn on the central control system, start the high-precision plunger pump and the ultrasonic generator of the process intensification reactor. At the same time, adjust the ball valve and needle valve to make the liquid pressures of the two conveying pipelines reach the set value of 1.0 MPa, so that the two reaction solutions flow into the process intensification reactor through the core reactor in a constant pressure and constant flow manner and are arranged at intervals. Under the cavitation effects such as enhanced mass transfer, reaction and crystallization of ultrasonic waves, they quickly react to generate micro-nano solid particles.

[0081] Step S4: Turn on the stirrer and ultrasonic generator of the aging reactor. The suspension prepared from the continuous flow reaction system flows into the glass reaction kettle, and continues to react for 14 hours at the set temperature, ultrasonic power and stirring speed to prepare ternary precursor particles, and then obtain dry powder after filtration, washing and drying. The scanning electron microscope photo of the prepared nano ternary precursor is as Figure 8 shown, and it can be seen that the particles are uniform and have good consistency.

[0082] Example 5

[0083] Prepare nano nickel powder by using the tabletop continuous flow reaction system of Example 1. The steps are as follows:

[0084] Step S1: Dissolve nickel sulfate in pure water to prepare a first reaction solution with a metal salt concentration of 0.6 mol / L. Dissolve 80% hydrazine hydrate, NaBH4, and sodium hydroxide in pure water to prepare a second reaction solution with a sodium hydroxide concentration of 0.8 mol / L, a hydrazine hydrate concentration of 2.0 mol / L, and a NaBH4 concentration of 0.1 mol / L. Heat both the first reaction solution and the second reaction solution to 80 °C, and pour them into two double-layer storage barrels of the solution metering system respectively. Cover the storage barrel lids connected with the conveying pipelines. Place the two storage barrels on two electronic scales respectively, and zero the display values of the electronic scales.

[0085] Step S2: Turn on the solution metering system, the continuous flow reaction system, and the process intensification reactor. Input the set values of parameters required for the reaction (the flow rate of the first reaction solution is 80 ml / min, and the flow rate of the second reaction solution is 120 ml / min), pressure of 0.6 MPa, temperature of 80 °C, ultrasonic power density of 2.8 W / cm 2 in the central control system. Set the temperature of the aging reactor to 80 °C, ultrasonic power density to 8.5 W / cm 2 , stirring speed to 420 rpm and other parameters. Turn on the temperature control system to make the core reactor, the process intensification reactor, and the aging reactor reach the set temperature values.

[0086] Step S3: Turn on the central control system, start the high-precision plunger pump and the ultrasonic generator of the process intensification reactor. At the same time, adjust the ball valve and needle valve to make the liquid pressures of the two conveying pipelines reach the set value of 0.6 MPa, so that the two reaction solutions flow into the process intensification reactor through the core reactor in a constant-pressure and constant-flow manner with shunt and arranged at intervals. Under the cavitation effects of ultrasonic enhanced mass transfer, reaction, crystallization, etc., they react quickly to generate micro-nano solid particles.

[0087] Step S4: Turn on the stirrer and ultrasonic generator of the aging reactor. The suspension prepared from the continuous flow reaction system flows into the glass reaction kettle, and continues to react for 3 hours at the set temperature, ultrasonic power, and stirring speed to prepare nano-nickel particles, which are then filtered, washed, and dried to obtain dry powder. The scanning electron microscope photos of the prepared nano-nickel particles are as Figure 9 shown, and it can be seen that the particles are uniform and have good consistency.

[0088] As can be seen from the above embodiments, the technical solution of the present invention comprehensively adopts the methods of space separation (liquid separation module, mixing chamber, and process intensification reactor) and time continuity. It not only solves the amplification effect problem caused by the mismatch between the three transfer rates and the reaction rate by relying on space separation, but also realizes the large-scale and macroscale preparation of micro-nano powders through time continuous accumulation.

[0089] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A bench-top continuous flow reaction system, characterized in that: It includes a core reactor and a process intensification reactor. The core reactor includes a first liquid inlet, a second liquid inlet, a first liquid distribution module, a second liquid distribution module and a mixing chamber. The first liquid inlet is connected to the inlet of the first liquid distribution module, and the second liquid inlet is connected to the inlet of the second liquid distribution module. The first liquid distribution module includes a number of first liquid distribution channels, and the second liquid distribution module includes at least two layers of spiral second liquid distribution channels. The first liquid distribution channels are located between adjacent spirals of the second liquid distribution channels; The mixing chamber is located at the outlets of the first liquid distribution module and the second liquid distribution module; The process intensification reactor includes an ultrasonic tank and an ultrasonic reaction pipeline placed in the ultrasonic tank. The outlet of the mixing chamber is connected to the inlet of the ultrasonic reaction pipeline; The number of the first liquid distribution channels is arranged in a ring shape; the liquid inlet angles of the first liquid inlet and the second liquid inlet are right angles.

2. The tabletop continuous flow reaction system according to claim 1, wherein: The second liquid distribution channels are arranged in an arc spiral or a polygon spiral.

3. The tabletop continuous flow reaction system according to claim 1, wherein: The ultrasonic reaction pipeline is a spiral pipe.

4. The bench-top continuous flow reaction system according to claim 1, wherein: It includes a circulating water system and a constant temperature water bath. The circulating water system is connected to the constant temperature water bath, and the circulating water system is connected to the core reactor and the process intensification reactor to control the temperatures of the core reactor and the process intensification reactor.

5. The tabletop continuous flow reaction system according to claim 4, wherein: The first liquid inlet is connected to a first conveying system, and the second liquid inlet is connected to a second conveying system. The first conveying system and the second conveying system respectively control the flow rates of the reaction liquids entering the first liquid inlet and the second liquid inlet, so that the flow rate difference between the two reaction liquids is 10 - 200%.

6. The bench-top continuous flow reaction system according to claim 5, characterized in that: Both the first conveying system and the second conveying system include a plunger pump and a connecting pipeline. A ball valve, a pressure gauge and a needle valve are provided on the connecting pipeline.

7. The tabletop continuous flow reaction system according to claim 4, wherein: The outlet of the ultrasonic reaction pipeline is connected to an aging reactor through a pipeline. The aging reactor is a double-layer reaction kettle with a stirrer, and an ultrasonic horn is provided in the reaction kettle. Circulating water is introduced into the interlayer of the double-layer reaction kettle to cooperate with the constant temperature water bath to achieve temperature control.

8. A method for preparing a micro-nano material, characterized in that: Prepared by using the tabletop continuous flow reaction system as claimed in claim 7, comprising the following steps: Step S1: Respectively convey two reaction liquids to the first liquid inlet and the second liquid inlet of the core reactor. One reaction liquid is divided into several branches through the first liquid distribution module and mixed with the annular branches formed by the other reaction liquid passing through the second liquid distribution module, and then enters the mixing chamber to obtain a mixed liquid; Step S2: Make the mixed liquid enter the process intensification reactor, and rapidly react to generate micro-nano particles under the conditions of a constant temperature water bath and the action of ultrasonic waves; Step S3: Make the mixture in the process intensification reactor enter the aging reactor. Circulating water is introduced into the interlayer of the double-layer reaction kettle, and further reaction is carried out under the action of the stirrer and the ultrasonic horn. After filtration, washing and drying, micro-nano powder is obtained.

9. The preparation method of the micro-nano material according to claim 8, characterized in that: In step S1, the conveying pressure is 0.15 - 1.2 Mpa, and the flow rate difference between the two reaction liquids is 10 - 200%; In step S2, the frequency of the ultrasonic wave is 20~100KHz, and the power density of the ultrasonic wave is 0.5~5W / cm 2 ; In step S3, the frequency of the ultrasonic horn is 20~100KHz, and the power density is 0.8~10W / cm 2 , the rotation speed of the stirrer is 80~600rpm, and the temperature of the circulating water is -20~90°C.

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