Airflow crushing system and airflow crushing method thereof

Abstract

The invention discloses an airflow crushing system and an airflow crushing method thereof, and belongs to the technical field of material pulverization. The airflow crushing system comprises an airflow crusher, a gas-solid separation device, an exhaust fan and an air supply fan, and a raw material inlet of the airflow crusher communicates with an air outlet of the air supply fan; a powder outlet of the jet mill is communicated with a feed port of the gas-solid separation equipment, and an exhaust port of the gas-solid separation equipment is communicated with an air inlet of the exhaust fan. The airflow crushing method comprises the steps that the airflow crusher crushes materials into powder, the powder is discharged into the gas-solid separation equipment to be separated, the exhaust fan pumps out gas in the gas-solid separation equipment, the gas supplementing fan supplements the gas into the airflow crusher, the exhaust fan and the gas supplementing fan are matched to maintain the pressure in the airflow crusher to be stable, a large amount of fine powder is prevented from being generated, and the crushing efficiency is improved. And the powder is discharged into gas-solid separation equipment in time, so that over-crushing is avoided, the qualification rate is increased, and the energy loss is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of material pulverization, and in particular to an airflow pulverization system and an airflow pulverization method thereof. Background Art

[0002] Airflow milling is a widely used powder processing equipment, which is widely used in battery materials, medicine, food processing and other fields. After hundreds of years of development, it has developed into powder processing equipment suitable for different fields, including jet jet mill, flat jet mill, circulating tube jet mill, fluidized bed jet mill, etc. The demand for powder materials is not only the fineness of the material, but also the particle size distribution of the material. Because the traditional airflow milling system generally adopts the exhaust fan exhaust method to provide a negative pressure state for the crushing chamber to lead the crushed material out, the pressure in the crushing chamber is difficult to maintain a stable state, resulting in an unstable crushing environment, and inevitably produces a large amount of fine powder, resulting in a wide particle size distribution. Moreover, many materials cannot be discharged in time after being crushed in the crushing chamber, resulting in over-crushing, reducing the qualified rate of powder materials, and also causing energy loss. Summary of the invention

[0003] The purpose of the present invention is to solve the above-mentioned technical problems and to provide an air flow pulverizing system and an air flow pulverizing method thereof. The exhaust fan and the air supply fan cooperate to maintain the entire air flow pulverizing system in a stable positive pressure or negative pressure state, provide a stable pressure environment for the pulverizing chamber of the air flow pulverizer, so that the air flow pulverizer can stably pulverize materials and avoid the large-scale generation of fine powder. At the same time, by supplying air or increasing the air supply through the air supply fan, the material in the air flow pulverizer can be discharged in time to avoid over-pulverization, improve the qualified rate and reduce energy loss.

[0004] To achieve the above-mentioned purpose, the present invention provides the following solution: The present invention discloses an air flow pulverizing system, comprising an air flow pulverizer, a gas-solid separation device, an exhaust fan and an air supply fan, the raw material inlet of the air flow pulverizer is connected to the air outlet of the air supply fan, the powder outlet of the air flow pulverizer is connected to the feed inlet of the gas-solid separation device, and the exhaust port of the gas-solid separation device is connected to the air inlet of the exhaust fan.

[0005] Preferably, the gas-solid separation equipment is a cyclone separator.

[0006] Preferably, a dust collector is further included, and the air inlet of the dust collector is connected to the exhaust port of the gas-solid separation equipment.

[0007] Preferably, the dust collector is a bag dust collector.

[0008] Preferably, the air outlet of the exhaust fan is connected to an exhaust pipe, and the air inlet of the air supply fan is connected to the exhaust pipe.

[0009] Preferably, the air flow pulverizer is a fluidized bed air flow mill pulverizer.

[0010] Preferably, the air supply fan and the exhaust fan are both volumetric fans.

[0011] Preferably, the volume blower is a Roots blower.

[0012] Preferably, the air supply fan and the exhaust fan are both controlled in frequency by a frequency converter.

[0013] Also disclosed is a gas flow pulverizing method, which uses the gas flow pulverizing system and includes the following steps:

[0014] The air flow pulverizer pulverizes the material into powder, which is then discharged into the gas-solid separation equipment for separation of material and gas. The exhaust fan extracts the gas in the gas-solid separation equipment, and the air supply fan replenishes the gas into the air flow pulverizer. The exhaust fan and the air supply fan cooperate to maintain the pressure in the air flow pulverizer stable, and discharge the powder into the gas-solid separation equipment in time for separation of powder and gas.

[0015] Compared with the prior art, the present invention has achieved the following technical effects:

[0016] In the present invention, the gas in the entire air flow pulverizing system can be extracted through the exhaust fan, and the gas can be replenished into the entire air flow pulverizing system through the air supply fan. The exhaust fan and the air supply fan work together to maintain the entire air flow pulverizing system in a stable positive pressure or negative pressure state, providing a stable pressure environment for the pulverizing chamber of the air flow pulverizer, so that the air flow pulverizer can stably pulverize the material into powder of qualified particle size, avoiding the large-scale generation of fine powder. At the same time, during the pulverizing process of the air flow pulverizer, the material in the air flow pulverizer can be discharged in time by replenishing air or increasing the air supply through the air supply fan, avoiding over-pulverization, improving the qualified rate, and reducing energy loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a structural schematic diagram of the airflow pulverizing system in the embodiment;

[0019] Figure 2 This is a SEM electron microscope image of the powder collected by the airflow pulverization system in this embodiment;

[0020] Figure 3 This is a SEM image of the powder collected using a traditional airflow pulverization system.

[0021] Explanation of the accompanying symbols: 1. air flow pulverizer; 2. gas-solid separation equipment; 3. dust collector; 4. exhaust fan; 5. exhaust pipe; 6. air supply fan. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1

[0024] This embodiment provides a jet milling system, such as Figures 1 to 3 As shown, it includes an airflow pulverizer 1, an air-solid separation device 2, an exhaust fan 4 and an air supply fan 6. The raw material inlet of the airflow pulverizer 1 is connected to the air outlet of the air supply fan 6, the powder outlet of the airflow pulverizer 1 is connected to the feed inlet of the air-solid separation device 2, and the exhaust port of the air-solid separation device 2 is connected to the air inlet of the exhaust fan 4.

[0025] Working principle:

[0026] The exhaust fan 4 can extract the gas in the entire air flow pulverizing system, and the air supply fan 6 can supply the gas to the entire air flow pulverizing system. The exhaust fan 4 and the air supply fan 6 can work together to maintain the entire air flow pulverizing system in a stable positive pressure or negative pressure state, thereby providing a stable pressure environment for the pulverizing chamber of the air flow pulverizer 1, so that the air flow pulverizer 1 can stably pulverize the material into powder with a qualified particle size, avoiding the large-scale generation of fine powder (fine powder refers to powder with a particle size smaller than the qualified powder particle size). The pulverized powder is sent into the gas-solid separation device 2 under the action of positive pressure or negative pressure, and the powder and gas are separated by the gas-solid separation device 2. The separated powder is discharged from the discharge port of the gas-solid separation device 2, and the gas is discharged from the exhaust port of the gas-solid separation device 2. During the pulverization process of the air flow pulverizer 1, the qualified pulverized materials in the air flow pulverizer 1 can be timely discharged by replenishing air or increasing the air supply through the air supply fan 6, avoiding over-pulverization, improving the qualified rate, improving production efficiency, and reducing energy loss.

[0027] In one embodiment, if Figures 1 to 3As shown, the gas-solid separation device 2 adopts a cyclone separator. Of course, this is just a better choice. If there are other suitable powder and gas separation devices, other forms of gas-solid separation devices can also be used. The cyclone separator is mainly composed of a cylindrical volute and a conical collecting section. The bottom of the conical section is a discharge port, and the discharge port is controlled by a star-shaped discharge valve or a double butterfly valve. Since the cyclone separator is an existing device, it will not be introduced in detail here.

[0028] In one embodiment, if Figures 1 to 3 As shown, the dust collector 3 is also included, and the air inlet of the dust collector 3 is connected to the exhaust port of the gas-solid separation device 2 (such as a cyclone separator). The dust collector 3 can intercept and collect the powder that has not been separated cleanly in the gas discharged from the gas-solid separation device 2, so as to avoid the powder being discharged with the gas, resulting in a waste of resources.

[0029] In one embodiment, if Figures 1 to 3 As shown, the dust collector 3 is a bag dust collector. As time goes by, the permeability of the bag of the bag dust collector may change, resulting in unstable pressure in the grinding chamber of the air flow mill 1. At this time, the pressure on both sides of the bag can be adjusted by cooperating with the air supply fan 6 and the exhaust fan 4 to avoid unstable pressure in the grinding chamber of the air flow mill 1. The bag dust collector is mainly composed of a metal frame, a filter bag, and a backflush device. The filter bag includes but is not limited to a metal filter bag or an organic material. The backflush device includes an air nozzle and an air bag. The air bag stores gas and releases all the gas in the air bag within 0-1s when backflush is required. The backflush pressure includes but is not limited to 0-0.5Mpa. Since the bag dust collector is an existing equipment, it will not be introduced in detail here.

[0030] In one embodiment, if Figures 1 to 3 As shown, the air outlet of the exhaust fan 4 is connected to the exhaust pipe 5, and the air inlet of the air supply fan 6 is connected to the exhaust pipe 5. This arrangement makes the gas exhausted by the exhaust fan 4 become the gas source of the air supply fan 6. Its purpose is to make the exhausted gas undergo a crushing cycle, and the materials that are not collected cleanly or not crushed in place in the gas can be crushed and collected again to avoid waste of resources.

[0031] In one embodiment, if Figures 1 to 3As shown, the air flow mill 1 is a fluidized bed type air flow mill mill. Of course, it is not excluded to use other forms of air flow mills, such as a jet type air flow mill mill, a flat type air flow mill mill, and a circulating tube type air flow mill mill. It is just that the fluidized bed type air flow mill mill is more suitable. The grinding chamber of the fluidized bed type air flow mill mill is supported by a support, and the feeding of the grinding chamber is fed by a star-shaped discharge valve or a spiral feeder or other uniformly controlled feeding methods. The system also feeds uniformly by controlling the feeding device through the grading motor current or torque. The bottom of the grinding chamber is a symmetrical Laval nozzle, which is symmetrically distributed. The nozzle is directly opposite to the central axis, and the upper part is composed of a grading wheel for material grading. The Laval nozzle uses gas from an air compressor or other device or equipment that provides pressure gas. The pressure range includes but is not limited to low pressure, medium pressure, high pressure or ultra-high pressure gas. The grading wheel can be controlled by a frequency converter to be a single-head or multi-head grading wheel. Because the fluidized bed type air flow mill mill is an existing device, its structure is not introduced too much here.

[0032] In one embodiment, if Figures 1 to 3 As shown, both the air supply fan 6 and the exhaust fan 4 are volumetric fans.

[0033] In one embodiment, if Figures 1 to 3 As shown, the volumetric blower is a Roots blower, and of course other forms of volumetric blowers can also be used. However, compared with centrifugal blowers, the gas flow of Roots blowers is more stable, thereby stabilizing the gas in the system, reducing air flow resistance, providing a stable crushing environment, and ensuring the stability of the crushing process.

[0034] In one embodiment, if Figures 1 to 3 As shown, the frequencies of the air supply fan 6 and the exhaust fan 4 are both controlled by frequency converters.

[0035] In one embodiment, if Figures 1 to 3 As shown, the pressure of the grinding chamber in the air flow grinder 1 is positive pressure or negative pressure, the positive pressure is preferably 0Kpa to 50Kpa, and the negative pressure is preferably -50 to 0Kpa.

[0036] In one embodiment, if Figures 1 to 3 As shown, a comparative experiment was conducted:

[0037] Experiment 1: The airflow mill 1 adopts a fluidized bed type airflow mill, the gas-solid separation device 2 adopts a cyclone separator, the dust collector 3 adopts a bag dust collector, the exhaust fan 4 and the air supply fan 6 both adopt Roots blowers, and an exhaust pipe 5 is provided. The crushing pressure of the fluidized bed type airflow mill (airflow mill 1) is adjusted to 800Kpa, the feed rate is adjusted to 30Kg / h according to the crushing situation, the classifying wheel speed of the fluidized bed type airflow mill is 5000 rpm, and the air supply volume of the air supply fan 6 is 500m 3 / h, under this condition, the crushing is carried out, and the cyclone separator (gas-solid separation equipment 2) receives the qualified material. Figure 2 Shown are SEM under these conditions.

[0038] Experiment 2: The airflow mill 1 adopts a fluidized bed type airflow mill, the gas-solid separation device 2 adopts a cyclone separator, the dust collector 3 adopts a bag dust collector, the exhaust fan 4 and the air supply fan 6 both adopt Roots blowers, and an exhaust pipe 5 is provided. The crushing pressure of the fluidized bed type airflow mill (airflow mill 1) is adjusted to 800Kpa, the feed rate is adjusted to 10Kg / h according to the crushing situation, the classifying wheel speed of the fluidized bed type airflow mill is 6000 rpm, and the air supply volume of the air supply fan 6 is 500m 3 / h.

[0039] Experiment 3: The airflow mill 1 adopts a fluidized bed type airflow mill, the gas-solid separation device 2 adopts a cyclone separator, the dust collector 3 adopts a bag dust collector, the exhaust fan 4 and the air supply fan 6 both adopt Roots blowers, and an exhaust pipe 5 is provided. The crushing pressure of the fluidized bed type airflow mill (airflow mill 1) is adjusted to 800Kpa, the feed rate is adjusted to 10Kg / h according to the crushing situation, the classifying wheel speed of the fluidized bed type airflow mill is 4000 rpm, and the air supply volume of the air supply fan 6 is 300m 3 / h.

[0040] Experiment 4: The air flow mill 1 adopts a fluidized bed air flow mill, the gas-solid separation equipment 2 adopts a cyclone separator, the dust collector 3 adopts a bag dust collector, the exhaust fan 4 adopts a centrifugal fan, and there is no air supply fan 6.

[0041] The powders obtained from the above experiments 1 to 4 were subjected to particle size test and SEM test and characterization:

[0042] Particle size test: Take 0.2g of the prepared material in a small beaker, add about 50ml of water and stir thoroughly, treat it in an ultrasonic bath for 5 minutes, then use a pipette to add it to a particle size analyzer for testing to obtain the particle size curve and results. The particle size test results are as follows:

[0043] Particle size test table

[0044] Particle size samples 0-2um / % D10 / um D50 / um D90 / um D100 / um Experiment 1 3.42 3.03 5.47 9 13.1 Experiment 2 1.43 3.52 5.69 8.91 12.7 Experiment 3 4.2 2.71 5.52 9.1 13.1 Experiment 4 7.9 1.8 5.49 9.7 13.5

[0045] SEM test: Take a small amount of material particles on the carbon tape and place it under an electron microscope for SEM scanning to obtain the SEM test results. The results of experiment 1 are as follows Figure 2 As shown in Figure 4, the results of Experiment 4 are as follows Figure 3 shown.

[0046] In summary, the powder fineness and particle size distribution of Experiments 1 to 3 were better than those of Experiment 4 which used the traditional air flow pulverizing system because the air flow pulverizing system was used.

[0047] Example 2

[0048] This embodiment provides a method for air flow pulverization, such as Figures 1 to 3 As shown, the airflow pulverizing system in Example 1 is used, comprising the following steps:

[0049] The air flow pulverizer 1 pulverizes the material into powder, and the powder is discharged into the gas-solid separation equipment 2 for separation of material and gas. The exhaust fan 4 extracts the gas in the gas-solid separation equipment 2 in a quantitative manner, and the air supply fan 6 replenishes the gas into the air flow pulverizer 1. The exhaust fan 4 and the air supply fan 6 cooperate to maintain the pressure in the air flow pulverizer 1 stable, and the powder is discharged into the gas-solid separation equipment 2 in time, and the gas-solid separation equipment 2 separates the powder and the gas.

[0050] In one embodiment, if Figures 1 to 3 As shown, the pressure of the grinding chamber in the air flow grinder 1 is positive pressure or negative pressure, the positive pressure is preferably 0Kpa to 50Kpa, and the negative pressure is preferably -50 to 0Kpa.

[0051] In one embodiment, if Figures 1 to 3 As shown, during pulverization, the entire system has two moving media, namely, the pulverized material flow and the gas flow; the material flows into the pulverizing chamber of the fluidized bed jet mill (jet mill 1) through a controllable feeding device, and the gas supplemented by the air supply fan 6 enters the pulverizing chamber synchronously. The material in the pulverizing chamber is pulverized by the shear force of mutual collision under the action of the counter-moving airflows, and the particles that have collided rise to the classifying wheel under the action of the rising airflow in the pulverizing chamber, and the powder with smaller particles is accelerated to a higher speed to pass through the classifying wheel, while the material with larger particles is accelerated to a higher speed to pass through the classifying wheel due to the lower speed. After the collision of the classifying wheel, it returns to the crushing area for crushing again. The material separated by the classifying wheel passes through the volute of the cyclone separator (gas-solid separation equipment 2) to separate the material and the gas, and the qualified material is collected. The gas containing some fine powder enters the bag dust collector (dust collector 3). The bag dust collector separates the fine powder and the gas through bag filtration. The fine powder is collected at the bottom of the bag dust collector, and the gas is discharged to the outside through the exhaust pipe 5 behind the exhaust fan 4. Part of it enters the crushing chamber of the fluidized bed jet mill through the exhaust pipe 5 and the air supply fan 6.

[0052] In one embodiment, if Figures 1 to 3 As shown, a comparative experiment was conducted. For the specific comparative experimental process and experimental results, refer to the comparative experiment in Example 1.

[0053] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A jet milling system, characterized in that: It includes an air flow pulverizer, a gas-solid separation device, an exhaust fan and an air supply fan. The raw material inlet of the air flow pulverizer is connected to the air outlet of the air supply fan, the powder outlet of the air flow pulverizer is connected to the feed inlet of the gas-solid separation device, and the exhaust port of the gas-solid separation device is connected to the air inlet of the exhaust fan.

2. The air flow pulverizing system according to claim 1, characterized in that: The gas-solid separation equipment is a cyclone separator.

3. A jet milling system according to claim 1 or 2, characterized in that: It also includes a dust collector, the air inlet of the dust collector is connected to the exhaust port of the gas-solid separation equipment.

4. The air flow pulverizing system according to claim 3, characterized in that: The dust collector is a bag dust collector.

5. The air flow pulverizing system according to claim 1, characterized in that: The air outlet of the exhaust fan is connected to an exhaust pipe, and the air inlet of the air supply fan is connected to the exhaust pipe.

6. The air flow pulverizing system according to claim 1, characterized in that: The air flow pulverizer is a fluidized bed type air flow mill pulverizer.

7. The air flow pulverizing system according to claim 1, characterized in that: The air supply fan and the exhaust fan are both volumetric fans.

8. The air flow pulverizing system according to claim 7, characterized in that: The volumetric blower is a Roots blower.

9. The air flow pulverizing system according to claim 1, characterized in that: The frequencies of the air supply fan and the exhaust fan are both controlled by frequency converters.

10. A jet milling method, characterized in that: The airflow pulverizing system according to any one of claims 1 to 9 is used, comprising the following steps: The air flow pulverizer pulverizes the material into powder, which is then discharged into the gas-solid separation equipment for separation of material and gas. The exhaust fan extracts the gas in the gas-solid separation equipment, and the air supply fan replenishes the gas into the air flow pulverizer. The exhaust fan and the air supply fan cooperate to maintain the pressure in the air flow pulverizer stable, and discharge the powder into the gas-solid separation equipment in time for separation of powder and gas.

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