System for preparing ultrafine powder through supercritical fluid technology

Abstract

The utility model relates to a system for preparing superfine powder by a supercritical fluid technology, which overcomes the defects that the existing supercritical fluid technology is combined with micro-jet, the discharging amount of the supercritical fluid technology is not uniform, and the quality of finished products is influenced; if the pressure and the temperature of the fluid obtained by the supercritical fluid technology are not balanced, the fluid directly enters the microjet, and a channel is easy to block; the system comprises a supercritical fluid reaction system, a fluid self-impact dispersion device and a discharging system which are connected in sequence, and the supercritical fluid reaction system comprises a supercritical fluid reactor and a supercritical fluid transition bin; and a feed port of the discharge system is provided with a fluid atomizing and spraying device. The supercritical fluid transition bin is arranged, the discharging amount can be accurately controlled, the pressure and temperature of supercritical fluid can be adjusted and balanced, and equipment is prevented from being blocked and damaged; and the fluid self-impact dispersing device enables particles in the fluid to collide with each other to reduce the particle size, so that the energy utilization rate is effectively improved, and the loss of equipment is small.

Description

Technical Field

[0001] The utility model relates to the technical field of ultrafine powders, in particular to a system for preparing ultrafine powders using supercritical fluid technology. Background Art

[0002] Supercritical fluid technology, typically using CO2 as the supercritical fluid medium, offers environmental advantages and is used in extraction, micronization, chromatographic separation, synthesis, and environmental remediation. For example, Chinese patent publication number CN 1621185 A discloses a "Method and Apparatus for Preparing Ultrafine Powders Using Ultrahigh-Pressure Supercritical Fluid Microjet Technology." This application of supercritical fluid technology to the preparation of ultrafine powders primarily involves combining supercritical fluid technology with ultrahigh pressure and microjet technologies to produce ultrafine powders with even smaller particle sizes.

[0003] However, the above technical solutions have the following defects: (1) there is no transition link between the supercritical fluid reaction process and the micro jet milling technology, and the discharge amount of the supercritical reactor cannot be accurately controlled, resulting in uneven discharge, which affects the quality of the finished product;

[0004] (2) The fluid channel of microjet technology is narrow. After the supercritical fluid reaction, the material without balanced and adjusted temperature and pressure directly enters the fluid channel of the microjet, which can easily cause powder blockage. The high-temperature material also affects the microjet technology device. (3) Microjet technology is a process in which the fluid enters a very fine nozzle with large kinetic energy and generates a very large flow rate. It hits the target at a supersonic speed of more than 500m / s, causing the object to be crushed under the high-speed impact. When the powder hits the target, the energy is unloaded by the target, and the energy utilization rate is not high. In addition, long-term direct impact on the target also causes certain damage to the equipment. Utility Model Content

[0005] The utility model overcomes the disadvantages of combining supercritical fluid technology with ultrahigh pressure and microjet technology to prepare ultrafine powder in the prior art, such as uneven discharge of supercritical fluid technology, which easily affects the quality of the finished product; the pressure and temperature of the fluid obtained by the supercritical fluid technology are not balanced and adjusted, and it directly enters the microjet link, which easily causes blockage of the microjet channel; and the disadvantages of low energy utilization and easy equipment loss. The utility model provides a system for preparing ultrafine powder using supercritical fluid technology.

[0006] In order to achieve the above invention objectives, the technical solution adopted by the present invention is: a system for preparing ultrafine powders using supercritical fluid technology, comprising: a supercritical fluid reaction system and a discharging system;

[0007] The supercritical fluid reaction system includes: a supercritical fluid reactor and a supercritical fluid transition chamber; the supercritical fluid transition chamber is provided with a device for adjusting pressure and temperature; the feed port of the supercritical fluid transition chamber is connected to the discharge port of the supercritical fluid reactor, and the pressure bearing capacity of the supercritical fluid transition chamber is similar to that of the supercritical fluid reactor;

[0008] A fluid self-impact dispersion device is provided between the supercritical reaction system and the discharge system; a fluid channel with a Y-shaped cross section is provided inside the fluid self-impact dispersion device; the feed port of the fluid self-impact dispersion device is connected to the discharge port of the supercritical fluid transition chamber;

[0009] The feed port of the discharging system is provided with a fluid atomizing injection device; the feed port of the discharging system is connected with the discharge port of the fluid self-impact dispersing device via the fluid atomizing injection device.

[0010] The beneficial effects of the present invention are as follows: (1) a supercritical fluid transition chamber is provided between the supercritical reaction system and the discharge system, and the high-pressure and high-temperature fluid in the supercritical reactor is transferred to the supercritical fluid transition chamber through a pressure difference. The pressure and temperature of the fluid in the supercritical fluid transition chamber can be adjusted according to process requirements, and the operation flexibility is higher;

[0011] (2) The application of supercritical fluid transition chamber can accurately control the amount of material in each supercritical expansion, prevent the uneven amount of material when directly discharging from the supercritical reactor, and avoid unstable quality of the finished product.

[0012] (3) The pressure and temperature of the fluid adjusted by the supercritical fluid transition chamber tend to be stable, reducing the impact and shock on the next process equipment, which is conducive to the next stage of the process;

[0013] (4) When the fluid passes through the Y-shaped cross-section of the fluid self-impact dispersion device at high speed, the particles in the fluid collide with each other when they meet at the Y-shaped intersection, achieving a dispersion effect. The energy utilization rate is significantly higher than that of the fluid directly impacting a fixed target, and there will be no loss to the target.

[0014] (5) A fluid atomizing injection device is provided at the feed port of the discharge system. When the supercritical fluid passes through the atomizing injection device, a supercritical fluid expansion effect is formed, and the supercritical fluid medium in the supercritical fluid is vaporized. The substance entering the discharge system is the prepared ultrafine powder, which is efficient and environmentally friendly. The particle size of the particles in the fluid will also be further reduced after passing through the fluid atomizing injection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attachment Figure 1 This is a schematic diagram of the overall system for preparing ultrafine powders using supercritical fluid technology in a utility model.

[0016] Attachment Figure 2 It is a cross-sectional view of the fluid self-impact dispersion device of the present invention.

[0017] In the figure, 1 is a supercritical fluid reaction system, 1-1 is a supercritical fluid reactor, 1-2 is a supercritical fluid transition chamber, 1-2-1 is an ultrasonic generator, 1-2-2 is a fluid pressurization and air supply device, 2 is a discharging system, 2-1 is a fluid atomization injection device, 2-2 is a powder classification bin, 2-2-1 is a fine powder discharge port, 2-2-2 is a powder classification wheel, 2-2-3 is a rotating crushing blade, 2-2-4 is a coarse powder hopper, 2-2-5 is a powder classification and air supply device, 2-3 is a fine powder discharge cyclone separator, 2-3-1 is a fine powder separation bin, 2-3-2 is an induced draft fan, 2-3-3 is a gas separator, 3-1 is a fluid self-impact dispersion device, and 3-1-1 is a fluid channel.

[0018] The present invention will be further described below through specific implementation methods. DETAILED DESCRIPTION

[0019] As attached Figure 1 As shown, a system for preparing ultrafine powder using supercritical fluid technology of the present invention includes: a supercritical fluid reaction system 1 and a discharge system 2.

[0020] The supercritical fluid reaction system 1 includes a supercritical fluid reactor 1-1 and a supercritical fluid transition chamber 1-2. The supercritical fluid reactor 1-1 is a conventional supercritical fluid reactor, capable of adjusting temperature and pressure, and having a supercritical fluid medium inlet, a device for mixing raw materials, and other equipment components required for a supercritical fluid reaction.

[0021] Supercritical fluid transition chamber 1-2 is equipped with adjustable pressure and temperature devices, allowing for adjustment of the pressure and temperature within supercritical fluid transition chamber 1-2 according to process requirements. The feed port of supercritical fluid transition chamber 1-2 is connected to the discharge port of supercritical fluid reactor 1-1. The pressure capacity of supercritical fluid transition chamber 1-2 is similar to that of supercritical fluid reactor 1-1, ensuring that supercritical fluid transition chamber 1-2 can receive the high-temperature, high-pressure fluid in supercritical fluid reactor 1-1. During operation, the internal temperature of both supercritical fluid reactor 1-1 and supercritical fluid transition chamber 1-2 can be adjusted between 35-120°C and the internal pressure between 7-20 MPa.

[0022] In the actual ultrafine powder preparation process, in order to further disperse the particles in the fluid, it is preferred to set an ultrasonic generator 1-2-1 on the supercritical fluid transition chamber 1-2 for ultrasonically dispersing the fluid in the supercritical fluid transition chamber. The supercritical fluid transition chamber 1-2 and the supercritical fluid reactor 1-1 are independent cavities. The ultrasonic generator 1-2-1 is set on the supercritical fluid transition chamber 1-2, which can achieve ultrasonic dispersion of the fluid without affecting the safety of the supercritical fluid reactor 1-1.

[0023] Preferably, a fluid pressurizing and gas-supplying device 1-2-2 is provided on the supercritical fluid transition chamber 1-2, and the gas added is the same as the medium gas used in the supercritical reaction in the previous stage.

[0024] The size of the supercritical fluid transition chamber 1-2 is generally set to 50mL-1L. The small size makes it easier to accurately control the amount of material for each supercritical expansion, solving the problem of uneven material amount when discharging directly from the supercritical fluid reactor 1-1, resulting in unstable quality of the finished product. And the small-volume transition chamber can make the ultrasonic dispersion effect of the ultrasonic generator 1-2-1 more uniform, and separate it from the supercritical fluid main reaction part (supercritical fluid reactor 1-1) for ultrasonic dispersion, so that the safety of this arrangement is higher. According to actual process requirements, gas can be supplemented by the fluid pressurization and air replenishing device 1-2-2 to increase the pressure in the supercritical fluid transition chamber 1-2 separately, thereby improving the subsequent fluid self-impact dispersion effect, and the expansion effect of the pressurized fluid when it is ejected through the fluid atomization injection device 2-1 is also better.

[0025] In the ultrafine powder preparation system of the present invention, a fluid self-impact dispersion device 3-1 is provided between a supercritical reaction system 1 and a discharge system 2. A fluid channel (3-1-1) with a Y-shaped cross section is provided within the fluid self-impact dispersion device 3-1. Specifically, the fluid first passes through separate primary fluid channels at high speed and then converges into the same secondary fluid channel at high speed, forming a high-speed fluid internal particle impact and collision at the intersection, which can effectively disperse the distribution of particles in the fluid and effectively reduce the particle size of the particles in the fluid. The diameter of the fluid channel is preferably 1mm-10mm.

[0026] The particles in the fluid entering the supercritical fluid transition chamber 1-2 are further dispersed by ultrasound, which is also conducive to smoothly entering the fluid channel 3-1-1 in the fluid self-impact dispersion device 3-1, preventing particles from clogging the fluid channel.

[0027] The feed port of the fluid self-impact dispersion device 3-1 is connected to the discharge port of the supercritical fluid transition chamber 1-2. In order to control the discharge rate of the supercritical fluid transition chamber 1-2 and the feed rate of the fluid self-impact dispersion device 3-1, a pulse ball valve is set on the fluid pipeline between the two.

[0028] To separate the supercritical reaction medium and powder in the fluid, a fluid atomizing spray device 2-1 is installed at the feed inlet of discharge system 2. This inlet is connected to the discharge outlet of the fluid self-impact dispersion device 3-1 via the fluid atomizing spray device 2-1. When the fluid passes through the fluid atomizing spray device 2-1, a supercritical fluid expansion effect is generated, vaporizing the medium used in supercritical fluid technology. The powder in the fluid is then sprayed into the discharge system 2, producing the desired ultrafine powder. The preferred nozzle for fluid atomizing spray device 2-1 is a piezoelectric ultrasonic atomizing nozzle, which effectively prevents powder clogging.

[0029] To further meet the demand for even smaller ultrafine powder particle sizes, the preferred discharge system 2 is a grading discharge system, comprising a powder grading bin 2-2 and a fine powder discharge cyclone 2-3 that separates fine powder from gas. The feed port of the powder grading bin 2-2 is connected to the discharge port of the fluid self-impact dispersion device 3-1, and the fluid atomizing spray device 2-1 is located at the feed port of the powder grading bin 2-2 of the discharge system 2.

[0030] In the grading and discharging system of the present application, a fine powder discharge port 2-2-1 is provided at the end of the powder grading bin 2-2 opposite to the powder grading bin feed port. A powder grading wheel 2-2-2 is provided at the end of the powder grading bin 2-2 near the fine powder discharge port 2-2-1. The powder grading wheel 2-2-2 sieves the powder entering the powder grading bin 2-2. Powder with smaller particles can pass through the grading wheel 2-2-2 and the fine powder discharge port 2-2-1 and enter the fine powder discharge cyclone separator 2-3. Powder with larger particles is crushed by the grading wheel 2-2-2, and the larger particles fall off. The fine powder particles that meet the requirements after crushing still pass through the powder grading wheel 2-2-2 and enter the fine powder discharge cyclone separator 2-3. The lower end of the powder grading bin 2-2 is equipped with a rotating crushing blade 2-2-3 for crushing the coarse powder. When turned on, it can crush larger particles of powder that have sunk into the powder grading bin 2-2 and powder that has fallen after being crushed by the powder grading wheel 2-2-2. A coarse powder hopper 2-2-4 is located at the lower end of the rotating crushing blade 2-2-3. After classification and crushing, the larger particles of powder fall into the coarse powder hopper 2-2-4 below for discharge.

[0031] The fine powder discharge cyclone separator 2-3 comprises: a fine powder separation bin 2-3-1, an induced draft fan 2-3-2 and a gas separator 2-3-3 connected in sequence; the fine powder separation bin 2-3-1 is a cylindrical bin body, as shown in the attached Figure 1As shown, the specific structure can be a silo body that combines a cylindrical upper end and a conical lower end; the feed port of the fine powder separation silo 2-3-1 is connected to the fine powder discharge port 2-2-1 of the powder grading silo; after the fine powder enters the fine powder separation silo 2-3-1, it rotates around the inner wall of the silo and falls into the conical silo body below and is discharged through the discharge port of the fine powder separation silo 2-3-1.

[0032] The gas separator 2-3-3 is installed on the exhaust port of the induced draft fan 2-3-2; the induced draft fan 2-3-2 is installed on the exhaust port at the opposite end of the feed port of the fine powder separation bin 2-3-1. The gas separator 2-3-3, the induced draft fan 2-3-2, the feed port of the fine powder separation bin 2-3-1, the fine powder discharge port 2-2-1 of the powder classification bin 2-2, and the fine powder discharge end of the powder classification wheel 2-2-2 correspond in sequence, forming the fine powder in the powder classification bin 2-2. The gas enters the fine powder separation bin 2-3-1 in sequence through the fine powder discharge end of the powder classifying wheel 2-2-2, the fine powder discharge port 2-2-1, and the feed port of the fine powder separation bin 2-3-1. The fine powder rotates along the cylindrical bin wall of the fine powder separation bin 2-3-1 and falls into the fine powder silo of the fine powder separation bin 2-3-1. The gas enters the induced draft fan 2-3-2 through the exhaust port of the fine powder separation bin 2-3-1 and is then separated by the gas separator 2-3-3.

[0033] A gas separator 2-3-3 is provided on the exhaust port of the induced draft fan 2-3-2. The gas in the fine powder is separated in the gas separator 2-3-3 through the induced draft fan. When the induced draft fan sucks the fine powder into the fine powder separation bin 2-3-1, in order to ensure the balance of the air pressure in the powder grading bin 2-2, it is preferred that a powder grading air supply device 2-2-5 is provided on the powder grading bin 2-2. In order to prevent the backflow of gas in the powder grading bin 2-2, a one-way valve is preferably provided on the gas pipeline between the powder grading air supply device 2-2-5 and the powder grading bin 2-2.

[0034] The gas added to the powder grading bin is generally nitrogen, so there are generally two gases in the powder grading bin 2-2: CO2 (supercritical fluid reaction medium) and nitrogen. The two gases can be separated by the gas separator 2-3-3 and then reused.

[0035] The system for preparing ultrafine powders using the above supercritical fluid technology is used to prepare ultrafine powders, including the following steps:

[0036] S1. Adding raw materials and a supercritical fluid reaction medium into a supercritical fluid reactor, controlling the temperature and pressure of the reactor to perform a supercritical reaction, and obtaining a fluid containing powder;

[0037] S2. Using the pressure difference between the supercritical fluid reactor and the supercritical fluid transition chamber, the fluid containing the powder obtained in S1 is transferred to the supercritical fluid transition chamber, and the temperature and pressure of the fluid are adjusted to obtain a fluid with balanced temperature and pressure;

[0038] S3, transferring the temperature and pressure balanced fluid obtained in S2 to the fluid self-impact dispersion device through a pulse-open ball valve, so that the powder particles in the fluid impact each other, thereby obtaining a fluid with reduced powder particle size;

[0039] S4. After the fluid with reduced powder particle size obtained in S3 enters the discharging system through the fluid atomizing injection device, the supercritical fluid medium is vaporized to obtain ultrafine powder.

[0040] In step S2 of the above preparation method, the fluid entering the supercritical fluid transition chamber can be ultrasonically dispersed by an ultrasonic generator to obtain a fluid with balanced temperature and pressure and dispersed powder particles, and the fluid is transferred to the supercritical fluid transition chamber for further ultrasonic dispersion, which is isolated from the supercritical fluid reactor, thereby achieving ultrasonic dispersion and effectively ensuring the safety of the system.

[0041] In step S4 of the above preparation method, the powder entering the discharging system is subjected to a powder grading bin to obtain coarse powder and fine powder, and the coarse powder is directly discharged; the fine powder is separated by a fine powder discharging cyclone separator to obtain ultrafine powder and gas; the gas is separated and recovered by a gas separator.

Claims

1. A system for preparing ultrafine powder using supercritical fluid technology, comprising: The supercritical fluid reaction system and discharge system are characterized in that: The supercritical fluid reaction system (1) comprises: a supercritical fluid reactor (1-1) and a supercritical fluid transition chamber (1-2); the supercritical fluid transition chamber (1-2) is provided with a device capable of adjusting pressure and temperature; the feed port of the supercritical fluid transition chamber (1-2) is connected to the discharge port of the supercritical fluid reactor (1-1), and the pressure bearing capacity of the supercritical fluid transition chamber (1-2) is similar to that of the supercritical fluid reactor (1-1); A fluid self-impact dispersion device (3-1) is provided between the supercritical fluid reaction system (1) and the discharge system (2); a fluid channel (3-1-1) with a Y-shaped cross section is provided inside the fluid self-impact dispersion device (3-1); the feed port of the fluid self-impact dispersion device (3-1) is connected to the discharge port of the supercritical fluid transition chamber (1-2); The feed port of the discharge system (2) is provided with a fluid atomizing spray device (2-1); the feed port of the discharge system (2) is connected to the discharge port of the fluid self-impact dispersion device (3-1) via the fluid atomizing spray device (2-1).

2. The system for preparing ultrafine powder using supercritical fluid technology according to claim 1, characterized in that: The discharging system (2) is a graded discharging system; The discharging system (2) comprises: a powder classification bin (2-2) and a fine powder discharging cyclone separator (2-3) for separating fine powder from gas; The feed port of the powder grading bin (2-2) is connected to the discharge port of the fluid self-impact dispersion device (3-1), and the fluid atomizing injection device (2-1) is arranged on the feed port of the powder grading bin (2-2) of the discharge system (2); A fine powder discharge port (2-2-1) is provided at one end of the powder grading bin (2-2) opposite to the powder grading bin feed port; a powder grading wheel (2-2-2) is provided at one end of the powder grading bin (2-2) near the fine powder discharge port (2-2-1); a rotating crushing blade (2-2-3) for crushing coarse powder is provided at the lower end of the interior of the powder grading bin (2-2), and a coarse powder hopper (2-2-4) is provided at the lower end of the rotating crushing blade (2-2-3); The fine powder discharging cyclone separator (2-3) comprises: a fine powder separation bin (2-3-1), an induced draft fan (2-3-2) and a gas separator (2-3-3) connected in sequence; The fine powder separation bin (2-3-1) is a cylindrical bin; the feed port of the fine powder separation bin (2-3-1) is connected to the fine powder discharge port (2-2-1) of the powder classification bin; The gas separator (2-3-3) is arranged on the exhaust port of the induced draft fan (2-3-2); the induced draft fan (2-3-2) is arranged on the exhaust port at the opposite end of the feed port of the fine powder separation bin (2-3-1); the gas separator (2-3-3), the induced draft fan (2-3-2), the feed port of the fine powder separation bin (2-3-1), the fine powder discharge port (2-2-1) of the powder classification bin (2-2), and the fine powder discharge end of the powder classification wheel (2-2-2) correspond in sequence to form the powder classification bin (2-2). The fine powder and gas in the fine powder separation bin (2-3-1) enter the fine powder separation bin (2-3-1) in sequence through the fine powder discharge end of the powder classifying wheel (2-2-2), the fine powder discharge port (2-2-1), and the feed port of the fine powder separation bin (2-3-1); the fine powder rotates along the cylindrical bin wall of the fine powder separation bin (2-3-1) and falls to the fine powder silo of the fine powder separation bin (2-3-1); and the gas enters the induced draft fan (2-3-2) through the exhaust port of the fine powder separation bin (2-3-1) and is then separated by the gas separator (2-3-3).

3. The system for preparing ultrafine powder using supercritical fluid technology according to claim 2, characterized in that: The powder grading bin (2-2) is provided with a powder grading air supply device (2-2-5).

4. The system for preparing ultrafine powder using supercritical fluid technology according to claim 1, characterized in that: The nozzle of the fluid atomizing spray device (2-1) is a piezoelectric ultrasonic atomizing nozzle.

5. The system for preparing ultrafine powder using supercritical fluid technology according to claim 1, characterized in that: The supercritical fluid transition chamber (1-2) is provided with an ultrasonic generator (1-2-1) for ultrasonically dispersing the fluid in the supercritical fluid transition chamber.

6. The system for preparing ultrafine powder using supercritical fluid technology according to claim 1, characterized in that: The supercritical fluid transition chamber (1-2) is provided with a fluid pressurizing and air-supplementing device (1-2-2).

7. The system for preparing ultrafine powder using supercritical fluid technology according to claim 1, characterized in that: A pulse ball valve is provided on the fluid pipeline between the supercritical fluid transition chamber (1-2) and the fluid self-impact dispersion device (3-1).

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