CN100336582C - Mixture device for multiple nozzle pollision flow - Google Patents

Abstract

The present invention discloses a collision flow mixing device with multiple nozzles, which comprises a nozzle core, annular distribution grooves, a fixing plate, and a V-shaped top cover, wherein the nozzle core is fixed in the middle of the distribution grooves by screw threads or in a welding mode; annular fluid channels are arranged between the nozzle core and the annular distribution grooves, and the annular distribution grooves are fixed on the fixing plate by screws; the fixing plate is clamped on the V-shaped top cover of which the lower part is connected with a crystallization container. The present invention has the advantages that the device of the present invention is used for preparing micro nanometer particles by supercritical fluid, and the prepared micro nanometer particles have small and even particle sizes; the device of the present invention is convenient to process and to manufacture and has good mixing performance.

Description

Multi-Nozzle Collision Stream Mixer

Technical field:

The invention relates to chemical equipment, in particular to a multi-nozzle collision flow mixer for preparing micro-nano particles, which is used for preparing micro-nano particles through supercritical fluid.

technical background:

The application of supercritical fluid technology can complete the particle processing of many heat-sensitive drugs and explosive and easily degradable substances, and has the characteristics of green environmental protection, so it has become a research hotspot at present. The supercritical solution rapid expansion method (RESS) is suitable for processing supercritical fluid soluble substances, and the relevant patent (Zhao Yaping. et al., CN02111918.X) has designed the trumpet-shaped nozzle aperture and shape of the nozzle. At present, various supercritical fluid anti-solvent technologies (SAS) are more concerned (Jung J & Perrut M. Journal of Supercritical Fluids 20: 179, 2001). SAS technology mixes supercritical fluid (SCF) with the solution of the substance to be treated, and completes the crystallization process in a supercritical state. Existing research results show that the crystal form and particle size distribution of the final granular product are closely related to the microscopic mixing and mass transfer process under nucleation conditions (Francisco C, Pablo D, etc. AIChE J42: 3156, 2003). Like the conventional crystallization process, SAS technology includes two steps of nucleation and grain growth. Ideally, the mixing process of SCF and the solution should be fully mixed flow, and the uniform characteristic time of the mixing of SCF and the treated substance solution should be sufficiently small to obtain micro-nano particles with uniform particle size. At the same time, plug flow should be maintained after mixing to avoid back-mixing of the generated particles with the solution of the substance being treated. SEDS (enhanced solution dispersion) is a kind of SAS technology, which requires simultaneous injection of SCF and solution, which is the closest to this ideal situation, and can realize the crystal form control of particle products (Kordikowski A, Shekunov T, York P.Pharm Res 18: 682.2001 ).

According to the micro-mixing theory, the homogenization characteristic time of micro-mixing decreases with the decrease of kinematic viscosity of the system, and the increase of energy dissipation rate in the mixing process can also shorten the characteristic time of micro-mixing homogenization. Another important factor to be considered in the mixing process is the mixing ratio. SEDS technology usually requires the volume of the SCF fluid involved in the mixing to be much larger than the volume of the material solution to be processed to complete the crystallization.

According to current literature reports, the most common mixing method of SEDS technology is the use of multi-channel coaxial nozzles. This mixing method has the following problems: First, the size of each channel where SCF and solution flow in should be small enough to ensure energy dissipation during the mixing process. rate. At the same time, in order to avoid flow dead angle in the mixing area, the volume of the mixing area should not be large. Therefore, the processing of related devices, especially the low-flow experimental device, is very difficult, and it is even more difficult to optimize the mixing state; second, after mixing the streams, they are directly sprayed into the crystallization vessel, and the residence time of the streams in the vessel is unevenly distributed, which affects the Particle size distribution of granular products. In addition, the energy dissipation rate of the mixing process in the coaxial nozzle is limited, and the microscopic mixing scale is difficult to reduce, which also brings inconvenience to the process design.

In order to improve the mixing effect, the patent (M. Hanna, US6440337B1) proposes a nozzle in the form of a collision flow to increase the energy dissipation rate of the mixing process. Since the coaxial multi-pipeline design is still adopted, the mixing device is composed of more than ten tiny components, which is more difficult to manufacture.

Invention content:

The purpose of the present invention is to provide a multi-nozzle collision flow mixing device which is convenient for processing and manufacturing, and can quickly mix the treated substance solution and supercritical fluid uniformly for the preparation of micro-nano particles.

The present invention mainly adopts two technical measures: the first one is to increase the number of colliding streams, and the mixing conditions under different mixing ratios can be optimized by adjusting the number of streams, thereby reducing the requirements on the machining accuracy of the nozzle shape; the second one It is to change the usual flow direction of the mixed material liquid. After the solution is mixed with the supercritical fluid, it surges upwards, and then enters the crystallization container below along the channel between the top cover and the distribution tank. The mixing nozzle and the top cover of the container form a mixed material flow. The distributor can promote the mass transfer of the nucleation process and improve the residence time distribution of the mixed liquid in the crystallization vessel.

The multi-nozzle collision flow mixing device of the present invention includes four parts: a nozzle core, an annular distribution groove, a fixed plate and a V-shaped top cover. The nozzle core is fixed in the middle of the annular distribution groove by threads or welding, and there is an annular Fluid channel, there are horn-shaped nozzles on the bottom and sides of the nozzle core. The center of the nozzle core is a cup-shaped mixing area. The small amount of material flow enters from the bottom nozzle, and the large amount of material flow enters from the side nozzles. The side nozzles have a downward angle to enhance Mixing effect, the angle between the side nozzle axis and the horizontal line is 5-50°, the number of side nozzles is 3-20, and the volume ratio of the supercritical fluid to the treated substance solution is adjusted. The volume of the cup-shaped mixing area should not be large to reduce Small mixing characteristic time, the volume is 0.5-50 ml; the annular distribution groove is fixed on the fixed plate by screws; the fixed plate is locked on the V-shaped top cover; the V-shaped top cover is connected to the crystallization container below through the flange.

The fixed plate is formed by supporting sheet 12, steel bar 13 and ring sheet 14 welding.

The shape of the annular distribution groove is a streamline or a garden arc, so as to avoid a dead zone inside the mixing device.

The material of the multi-nozzle collision flow mixing device is selected from stainless steel, engineering plastics or ceramic materials.

The multi-nozzle collision flow mixing device of the present invention has a simple structure, is convenient for processing and manufacturing, and has good mixing performance.

The work is reliable and stable, and micro-nano particles are prepared by supercritical fluid, and the particle size of the obtained micro-nano particles is small and uniform.

Description of drawings and specific implementation

Fig. 1 is a schematic structural view of a multi-nozzle collision flow mixing device of the present invention.

Fig. 2 is a top view of the fixed nozzle core and the annular fluid distribution groove.

Figure 3 is a schematic diagram of the shape of the fixing plate.

As shown in Figure 1, the multi-nozzle collision flow mixing device of the present invention includes four parts: a nozzle core 4, an annular distribution groove 2, a fixed plate 6 and a V-shaped top cover 1. There is an annular fluid channel 8 between the nozzle core and the annular distribution groove. The annular distribution groove is fixed on the fixed plate by screws 5, and the fixed plate is formed by welding the support piece 12, the steel bar 13 and the ring piece 14. During use, the ring piece 14 is locked on the inner surface of the V-shaped top cover, and under the V-shaped top cover, the Connect the crystallization container;

The distribution of multiple nozzles on the side of the nozzle core is shown in Figure 2;

The specific structural form of the fixed plate is shown in Figure 3.

When the multi-nozzle collision flow mixing device of the present invention is in use, the supercritical fluid first passes through the side wall of the V-shaped top cover, enters the annular channel 8 through the pipeline 10 and the connecting piece 9, and then passes through the horn-shaped nozzles 3 of a certain number and aperture. , is mixed with the solution in the mixing zone 11 in the center of the nozzle core. The solution also passes through the side wall of the V-shaped top cover, and enters the mixing area 11 from the trumpet-shaped nozzle 3 at the bottom of the nozzle core through the pipeline 7 .

Use the multi-nozzle collision flow mixing device of the present invention to carry out polylactic acid ultrafine experiments. The device is made of stainless steel, and the volume of the mixing area is 4.2 milliliters. The acetone solution of polylactic acid is sprayed from the bottom of the nozzle core, and the supercritical carbon dioxide fluid is sprayed from the side of the nozzle core. Three nozzles are sprayed in, the inclination angle of the side nozzle is 20°, and the flow rate of the supercritical carbon dioxide fluid is controlled at about 30 times the flow rate of the solution. 1 micron-sized polylactic acid particles and carbon dioxide fluid flow out through the sintered porous plate at the bottom of the crystallization vessel.

Use the multi-nozzle collision flow mixing device of the present invention to carry out polystyrene ultrafine experiments. The device is made of stainless steel. The volume of the mixing area is 6.6 milliliters. The toluene solution of polystyrene is sprayed from the bottom of the nozzle core, and the supercritical carbon dioxide fluid is injected from the nozzle. Six nozzles on the side of the core are sprayed in, the inclination angle of the side nozzles is 30°, and the flow rate of the supercritical carbon dioxide fluid is controlled at about 50 times the flow rate of the solution. After the two are mixed, they enter the crystallization vessel with a pressure of 10Mpa and a temperature of 38°C, and the particle size can be obtained quickly. 0.5-1.5 micron-sized polystyrene particles and carbon dioxide fluid flow out through the sintered porous plate at the bottom of the crystallization vessel.

Claims (3)

1. A multi-nozzle collision flow mixing device, characterized in that it includes four parts: a nozzle core, an annular distribution groove, a fixed plate and a V-shaped top cover. The nozzle core is fixed in the middle of the annular distribution groove by threads or welding, and the nozzle core and the annular distribution groove There is an annular fluid channel between the grooves. There are trumpet-shaped nozzles on the bottom and sides of the nozzle core. The center of the nozzle core is a cup-shaped mixing area. The small amount of material flow enters through the bottom nozzle, and the large amount of material flow enters through the side nozzle. There is a downward inclination to enhance the mixing effect. The angle between the axis of the side nozzle and the horizontal line is 5-50°. The number of side nozzles is 3-20. It is adjusted according to the volume ratio of the supercritical fluid and the solution of the substance to be treated. The volume of the cup-shaped mixing area It should not be too large to reduce the mixing characteristic time. The volume is 0.5-50ml; the annular distribution groove is fixed on the fixed plate by screws; the fixed plate is fixed on the V-shaped top cover; the V-shaped top cover is connected to the bottom through the flange crystallization container. 2. A multi-nozzle collision flow mixing device according to claim 1, characterized in that the fixed plate is composed of a support plate, a steel bar and a ring plate welded together. 3. A multi-nozzle collision flow mixing device according to claim 1, characterized in that the shape of the annular distribution groove is streamlined or arc-shaped.

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