CN106693810A - Micromixer for fluid materials - Google Patents

Abstract

A micro-mixing device for fluid materials is composed of multi-channel thin-walled microporous ceramic elements, container shells, seals and other main parts. Two kinds of fluid materials flow in from the inner channel and the outer space of the multi-channel thin-walled microporous ceramic element respectively, and one of the materials enters the space of the other material through the ceramic thin wall and mixes with it. The multi-channel thin-walled microporous ceramic element can be produced through a low-cost process, and the microporous ceramic element has a wide range of sizes and shapes, and can be easily fabricated into micro devices or large-scale equipment to meet the needs of different process scales. In many industries such as chemical, pharmaceutical, food and environmental protection.

Description

A micro-mixing device for fluid materials

technical field

The invention relates to the fields of inorganic non-metallic materials, chemical industry, pharmacy, food and environmental protection, and in particular to the manufacture of a micro-mixing device and its application in a fluid mixing process.

Background technique

The microchemical process is also recognized as one of the new important fields in the development of chemical engineering, and microchemical devices have gradually become its important members, such as micromixers, microreactors, microchemical analysis instruments, microheat exchangers, microextractors, etc. Devices, micro pumps, micro valves, etc. Some research results of existing miniature chemical devices show that the reaction conversion rate and selectivity are significantly improved under micro-scale conditions, the heat transfer coefficient is greatly improved compared with traditional equipment, and the interphase mass transfer efficiency is also greatly improved compared with traditional equipment. improve.

Fluid mixing is a basic and important process, which is widely used in many fields such as chemical industry, pharmaceutical, food and environmental protection. The uniform and efficient mixing of fluid materials is of great significance to the control of product quality and production cost. Micro-mixing is an important way to achieve uniform and efficient mixing of materials. Micro-mixers are generally realized through micro-channels, and two fluids flow in two channels respectively, and then join together to play the role of mixing fluids. The micro-channel is generally 10 ~ 500mm, and the micro-mixing device generally includes several or even dozens of micro-channels. There are two main forms of fluid micro-mixing: (1) Micro-contact, that is, immiscible two-phase systems such as liquid-liquid or gas-liquid two-phase fluid flow in the same microchannel or in two microchannels that are in contact with each other. , form a parallel fluid layer, and realize the micro-contact of the two phases through the phase interface; (2) micro-mixing or micro-dispersion, that is, two miscible fluids or two immiscible fluids enter the micro-mixing or micro-dispersion area through the microchannel , to achieve micro-mixing or micro-dispersion of two fluids.

Practice has shown that the most important characteristics of the micro-mixing process: (1) high mixing efficiency, short residence time, and low energy consumption; (2) simple equipment structure, no amplification effect; (3) easy to control operating conditions, chemical reactions, Good mass transfer and heat transfer performance; (4) The equipment is small in size and has good intrinsic safety performance. Because of these characteristics, the research on micro-mixing chemical process and the development of micro-mixing equipment have been highly valued and important progress has been made in the past ten years.

Traditional micro-mixing equipment requires the use of laser engraving, electrical discharge machining, and electrochemical etching. Therefore, the production cost of the equipment is high, and it is difficult to manufacture large-scale micro-mixing equipment. It is often only used in small mixing and reaction systems such as pharmaceuticals and fine chemicals. With the development of material technology and molding process, micro-mixing equipment based on microporous membranes has gradually been developed. The microporous membrane has a porosity of more than 25%, and the pore size ranges from nanometers to micrometers, so it can provide a huge mixing interface and approximately uniform microscopic mixing for the fluids on both sides of the membrane. Moreover, large-scale microporous membranes can be produced on a large scale, so micro-mixing equipment is no longer limited to small and expensive.

Ceramics have the advantages of high strength, excellent chemical corrosion resistance, biological erosion resistance, high temperature resistance and easy cleaning. Micro-mixing devices based on porous ceramic materials such as oxides and carbides have broad application prospects in many industries such as chemical industry, pharmaceuticals, food and environmental protection.

Contents of the invention

The object of the present invention is to apply a porous ceramic element with a thin-walled multi-channel structure to micro-mixing devices and equipment. The multi-channel thin-walled microporous ceramic element can be produced through a low-cost process, and the microporous ceramic element has a wide range of sizes and shapes, and can be conveniently manufactured into micro devices or large equipment to meet the needs of different process scales. The micro-mixing device and equipment have the characteristics of low production cost, low operating energy consumption, high mixing efficiency, chemical corrosion resistance, etc., and can be widely used in many industries such as chemical industry, pharmaceuticals, food and environmental protection.

For reaching this purpose, the present invention adopts following technical scheme:

A micro-mixing device for fluid flow mixing, which is composed of multi-channel thin-walled microporous ceramic elements, container shells, seals and other main parts. The ceramic element has a thin-wall multi-channel structure, and the thin wall of the ceramic element has micropores through which liquid and/or gas can permeate.

Preferably, the ceramic element is made of one or more materials including but not limited to alumina, silicon carbide, quartz, cordierite, mullite and the like.

The basic steps in the manufacture of the ceramic element include:

1) mixing the ceramic raw material powder and firing aids to make mud;

2) extruding the mud into a green body;

3) drying and shaping the green body;

4) Sintering the dried green body into porous ceramics.

During extrusion molding, the ceramic element blank forms a certain channel structure and shape through the action of a mold. The cross-sectional shape of the channel includes, but is not limited to, geometric shapes such as circle, rectangle, and regular hexagon. The thickness of the ceramic thin wall is 0.2-2 mm. The shape of the ceramic element may include but not limited to a geometric shape such as a flat plate, a cylinder, and a square cylinder.

The multi-channel structure enables the ceramic element to use less ceramic material to reduce the weight of the device, while ensuring that the thin wall has sufficient mechanical strength. For example, multi-channel ceramic elements made of alumina can withstand gas or liquid pressures in excess of 7 bar at a wall thickness of 0.9 mm. Not only that, compared with thick-walled porous ceramic elements, the thin-wall reduces the resistance to fluid passage, obtains higher flux at lower pressure, and can achieve microscopic homogeneous mixing in a microdynamic manner.

The thin wall of the ceramic element is a transparent porous ceramic with a porosity of 25% to 85% and a pore size of 0.05 to 20 μm. Gas or liquid can penetrate from one side of the ceramic thin wall to the other under a certain pressure. side.

In order to obtain a suitable porous structure, it is necessary to determine the appropriate raw materials for the manufacture of the ceramic element. The particle size of the ceramic raw material powder has the most important influence on the microporous structure of the ceramic element. The median particle size of ceramic raw material powder is generally 0.1 ~ 70 μm. Preferably, the median particle size of the ceramic raw material powder is 0.2-40 μm.

The micro-mixing device disclosed by the present invention is composed of the main parts such as the multi-channel thin-walled microporous ceramic element, the container shell, and the seal. The inner channel and the outside of the multi-channel thin-walled microporous ceramic element are separated into independent space. The micro-mixing device is characterized in that two fluid materials flow in from the inner channel and the outer space of the multi-channel thin-walled microporous ceramic element respectively, and one of the materials enters the space of the other material through the ceramic thin wall, and is combined with Mixing occurs.

Due to the high porosity and small pore size on the thin wall of the ceramic element, the fluid material passing through the ceramic thin wall enters another fluid material in a dense and fine-sized form, forming a huge phase interface with it , so as to achieve high-efficiency micro-mixing.

In particular, according to equipment and process requirements, one of the two outer walls of the ceramic element can be coated with an organic coating or an inorganic coating, so that the micropores on the ceramic thin wall are closed to prevent the material from seeping out.

The micro-mixing device can be used for liquid-liquid, liquid-gas and gas-gas mixing, can be used for physical mixing of fluid materials, and can also be used for mixing reactions of materials.

The beneficial effect of the present invention is that: a micro-mixing device made of a porous ceramic element with a thin-walled multi-channel structure is proposed. The production method of this micro-mixing device is simple, raw materials are saved, equipment volume is reduced, and energy consumption is low in operation. The mixing efficiency is high, and it can be applied to micro and large fluid material mixing processes.

Description of drawings

Fig. 1 is the schematic diagram of a kind of thin-walled multi-channel ceramic element of flat plate shape, cylinder shape and square tube shape respectively;

Fig. 2 Schematic diagram of a micro-hybrid device based on a flat multi-channel ceramic element;

Fig. 3 Schematic diagram of a micro-mixing device based on a cylindrical multi-channel ceramic element;

The parts are: container shell 1, flat multi-channel ceramic element 2, cylindrical multi-channel ceramic element 21, sealing head 3, plastic sealing head 31, material one inlet 4, material two inlet 5, plastic sealing head 51 , Mixed material outlet 6.

detailed description

The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation methods.

A micro-mixing device for fluid flow mixing, which is composed of multi-channel thin-walled microporous ceramic elements, container shells, seals and other main parts. The ceramic element has a thin-wall multi-channel structure, and the thin wall of the ceramic element has micropores through which liquid and/or gas can permeate.

Fig. 1 is a schematic diagram of three kinds of multi-channel thin-walled microporous ceramic elements, and the ceramic elements respectively have the shapes of flat plate, cylinder and square cylinder. There is a group of small-sized passages arranged in parallel and independently penetrating in the ceramic element. The cross-sectional shape of the channel includes, but is not limited to, geometric shapes such as circular and rectangular. The size of the section is between 0.5 and 10 mm. The shape and structure of the ceramic element can be easily obtained by extrusion molding process. And theoretically, the length and cross-sectional dimensions of the ceramic element are limited only by the scale of the production equipment. Thus, micro and large said ceramic elements can be produced using a simple process, and accordingly, micro micro-mixing devices and large-scale micro-mixing devices can be produced.

To obtain devices and equipment with micro-mixing functions, it is necessary to assemble the ceramic element with the container shell with a seal, and separate the inner channel and the outer part of the multi-channel thin-walled microporous ceramic element into independent spaces, so that the two fluids Materials can flow in from the inner channel and the outer space of the ceramic element, respectively. One of the materials enters the space of the other material through the ceramic thin wall and mixes with it.

The micro-mixing device can be used in processes such as liquid-liquid, liquid-gas and gas-gas mixing.

Specific embodiment 1

A micro-mixing device based on a flat multi-channel ceramic element, the structure of which is shown in Figure 2.

Wherein, the flat multi-channel ceramic element is a porous alumina material. The manufacturing steps of the ceramic element are as follows:

1. Mix 4 kg of alumina powder with a median particle size of 20 μm and 0.2 kg of firing aids evenly;

2. Add 300 g of methyl cellulose, 150 g of glycerin, 15 g of oleic acid, 150 g of vacuum mineral oil and 900 g of water, and through the steps of mixing, mud refining, aging, etc., to obtain plastic mud;

3. Use an extruder to extrude the mud into a flat multi-channel green body;

4. The green body is dried by microwave radiation;

5. The dried green body is heated up to 400°C at a speed of 2°C/min and kept for 1 hour, and then heated to 1400°C at a speed of 2°C/min for 2 hours, and then cooled with the furnace.

After the fired ceramic product is cut, a flat multi-channel ceramic element 2 as shown in Figure 1 is obtained. It is 1200 m ³ /m ² h×bar.

Make the shell 1 of cuboid shape with 304 stainless steels. There are openings at both ends of the stainless steel shell 1, and the ceramic element 2 can be embedded in it; the space between the ceramic element 2 and the stainless steel shell 1 is sealed with a silicon rubber gasket; one end of the ceramic element 2 is sealed with a sealing head 3 to prevent the outflow of fluid materials; The other end of the element 2 is the inlet 5 of the material 2; a material port is provided on the upper and lower sides of the shell 1, wherein the lower material port is the inlet 4 of the material 1, and the upper material port is the outlet 6 of the mixed material.

In practical application, the micro-hybrid device in this example needs to be combined with electrical equipment. Electrical equipment includes metering pumps, PLC control systems, etc. Material 1 and material 2 are respectively pumped into the micro-mixing device by a metering pump at a certain flow rate. Wherein, a slightly higher pressure is applied to the material 2, so that the material 2 penetrates from the channel of the ceramic element 2 into the material 1 outside the channel through the porous thin wall, and rapidly mixes with the material 1.

The pressure of the mobile phase of material 2 is 0.1 bar higher than that of material 1, so that material 2 can penetrate into material 1, realizing microdynamic mixing.

Specific embodiment 2

A micro-mixing device based on a flat multi-channel ceramic element, the basic structure of which is similar to the specific example 1, except that the micro-mixing device includes 10 ceramic elements 2 arranged in parallel. By increasing the number of ceramic elements 2, the material handling capacity of the micro-mixing device can be conveniently increased.

Specific embodiment 3

A micro-mixing device based on a cylindrical multi-channel ceramic element, the basic structure of which is shown in Figure 3.

Wherein, the cylindrical multi-channel ceramic element is a porous silicon carbide material. The manufacturing steps of the ceramic element are as follows:

1. Mix 4.5 kg of black silicon carbide powder with a median particle size of 12 μm, 0.3 kg of kaolin with a median particle size of 0.5 μm, and 0.2 kg of alumina powder with a median particle size of 0.5 μm;

2. Add 300 g of hydroxypropyl methylcellulose, 120 g of glycerin, 15 g of oleic acid, 120 g of vacuum mineral oil and 850 g of water, and through the steps of mixing, mud refining, aging, etc., to obtain plastic mud;

3. Use an extruder to extrude the mud into a circular multi-channel green body;

4. After drying the green body at room temperature for 24 hours, put it in an oven at 80°C for 8 hours;

5. The dried green body is heated up to 400°C at a speed of 2°C/min and kept for 1 hour, and then heated to 1350°C at a speed of 2°C/min for 2 hours, and then cooled with the furnace.

The fired ceramic product was cut to obtain a cylindrical multi-channel ceramic element as shown in Figure 1, with a length of 200 mm, a diameter of 40 mm, and a thin wall thickness of 1 mm. The pore diameter of the separation membrane is 0.7 μm, and the gas flux is 2700 m ³ /m ² h×bar.

The outer wall of the cylindrical ceramic element 21 is coated with epoxy resin paint, and the micropores of the outer wall are closed to prevent fluid seepage. Afterwards, the ceramic element 21 is packaged with a plastic sealing head 31 and a plastic sealing head 51, so that the middle of the cylinder becomes a flow passage for material one, and the second material enters the narrow and long parallel passage in the ceramic element 21 from the inlet 5, and passes through The inner wall of the ceramic element 21 enters the flow channel of the material one.

The above describes the technical principles of the present invention in conjunction with specific embodiments. These descriptions are only for explaining the principles of the present invention, and cannot be construed as limiting the protection scope of the present invention in any way. Based on the explanations herein, those skilled in the art can think of other specific implementation modes of the present invention without creative efforts, and these modes will all fall within the protection scope of the present invention.

Claims (8)

1. the microring array device of a kind of fluid foods, it is characterised in that the microring array device is by multichannel thin-walled microporous ceramics The major parts such as element, shell of tank, seal are constituted, by shell of tank and seal multichannel thin-walled microporous ceramics unit The internal gutter of part and outside are separated into independent space.

2. multichannel thin-walled microporous ceramic component described in claim 1, it is characterised in that the multichannel of the ceramic component is logical Cross the gallery being parallel to each other that the mode of extrusion molding is formed；The section of passage be include and be not limited to circular, rectangle and The geometries such as regular hexagon.

3. multichannel thin-walled microporous ceramic component described in claim 1, it is characterised in that the material of the ceramic component is to include And it is not limited to the ceramics such as aluminum oxide, carborundum, quartz, cordierite, mullite.

4. multichannel thin-walled microporous ceramic component described in claim 1, it is characterised in that the ceramic thin wall thickness of the ceramic component It is 0.2 ~ 2 mm to spend.

5. the ceramic thin-walled of ceramic component described in claim 4, it is characterised in that the ceramic thin-walled is penetrating porous pottery Porcelain, porosity is 25% ~ 85%, and pore-size is 0.05 ~ 20 μm.

6. microring array device described in claim 1, it is characterised in that two kinds of fluid foods are respectively from the multichannel thin-walled microporous The inner passage of ceramic component and exterior space are flowed into, and one of which material enters the sky of another material through ceramic thin-walled Between, and mix therewith.

7. multichannel thin-walled microporous ceramic component described in claim 1, it is characterised in that according to equipment and technique needs, can be with Side coating organic coating or inorganic coating in the outer wall of the ceramic component both sides, make the micropore quilt on the ceramic thin-walled Closing, it is to avoid material is infiltrated.

8. the method for multichannel thin-walled microporous ceramic component described in manufacturing claims 1, it is characterised in that its step includes： 1） Mix the ceramic material powder and adjuvant for combustion is made pug； 2）The pug extrusion molding is made base substrate； 3）By institute State body drying sizing； 4）By the dry blank sintering into porous ceramics.