Ultrafine powder preparation device

Abstract

The invention discloses an ultrafine powder preparation device, and belongs to the field of powder preparation. Comprising a crushing chamber, and the crushing chamber is provided with a collision area, a heating area and a grading area from bottom to top; the collision area is provided with a feeding port formed in the side wall of the crushing chamber and at least one pair of airflow nozzles located on the lower side of the feeding port. The heating area is provided with a heating chamber with two open ends and an electromagnetic induction coil wound on the outer side of the heating chamber; and the grading area is provided with a grading wheel which is used for carrying out grading treatment on the powder passing through the collision area and the heating area. According to the device, secondary crushing of powder materials is achieved, the powder crushing efficiency is improved, and the grading efficiency of the device can be improved through the arrangement of the heating chamber.

Description

Technical Field

[0001] The present invention relates to the field of ultrafine powder preparation, and particularly to an ultrafine powder preparation device. Background Art

[0002] With the rapid development of clean coal technologies such as fine coal water slurry and coal-based materials, the preparation of ultra-clean coal has become crucial.

[0003] Generally, the smaller the particle size of ultrafine coal powder, the more fully the minerals are dissociated, and the lower the ash content obtained after separation. Therefore, in the existing process of preparing ultra-clean coal, ultrafine grinding is a key link and prerequisite. At present, traditional mechanical grinding methods cannot fully dissociate the minerals and organic matter in coal. The reason is that the direct effect of mechanical grinding is only to reduce the particle size of coal, rather than a special process for separating organic carbon and inorganic matter in coal. In addition, during the grinding process, oxidation of the coal particle surface will occur, and a large amount of dust will be generated, causing environmental pollution and safety hazards. These factors limit the preparation effect of ultra-clean coal. Summary of the Invention

[0004] Therefore, the present invention provides an ultrafine powder preparation device that combines gas-phase power crushing and electromagnetic induction rapid heating.

[0005] In view of the above technical problems, the present invention provides the following technical solutions:

[0006] An ultrafine powder preparation device, comprising: a crushing chamber, which is respectively provided with a collision zone, a heating zone, and a classification zone from bottom to top; the collision zone has a feed port installed on the side wall of the crushing chamber and at least a pair of gas nozzles located below the feed port; the heating zone has a heating chamber with openings at both ends and an electromagnetic induction coil wound around the outside of the heating chamber; the classification zone has a classification wheel for classifying the powder passing through the collision zone and the heating zone.

[0007] In some embodiments of the present invention, the crushing chamber, the heating chamber, and the classification wheel are coaxially arranged, and the opening area on the upper side of the heating chamber is smaller than the area of the classification wheel.

[0008] In some embodiments of the present invention, the heating chamber is integrally cylindrical, and its upper opening and / or lower opening has a horn-shaped flared structure.

[0009] In some embodiments of the present invention, the inner wall of the heating chamber is provided with a number of blocking protrusion structures, and the upper surface of the blocking protrusion structure is an inclined surface or an upwardly convex arc surface.

[0010] In some embodiments of the present invention, the electromagnetic induction coil is a water-cooled electromagnetic induction coil. A first heat insulation layer is provided between the electromagnetic induction coil and the heating chamber, and a second heat insulation layer is provided outside the electromagnetic induction coil.

[0011] In some embodiments of the present invention, a wear-resistant metal layer is provided outside the second heat insulation layer.

[0012] In some embodiments of the present invention, the electromagnetic induction coils are arranged in multiple groups, and the multiple groups of electromagnetic induction coils form multiple groups of electromagnetic induction circuits.

[0013] In some embodiments of the present invention, the relationship between the distance L between the lower side surface of the heating chamber and the center line of the air flow nozzle and the diameter D of the crushing chamber in the area where the air flow nozzle is located is: L ≥ 0.6D.

[0014] In some embodiments of the present invention, the crushing chamber further includes a waste discharge area located below the air flow nozzle, and a waste outlet is provided at the bottom of the waste discharge area.

[0015] In some embodiments of the present invention, a discharge port is provided above the classification area of the crushing chamber. The discharge port is communicated with a conveying pipeline, and a temperature sensor is provided on the conveying pipeline. The electromagnetic induction circuit where the electromagnetic induction coil is located is controlled according to the detection signal of the temperature sensor.

[0016] The technical solution of the present invention has the following technical effects compared with the prior art:

[0017] In the ultrafine powder preparation device provided by the present invention, a collision area and a heating area are provided in the crushing chamber to realize secondary crushing of the powder material, improving the powder crushing efficiency. The heating chamber adopts electromagnetic induction heating, which has the advantages of fast heating speed and simple equipment. It can quickly increase the temperature of the pulverized coal entering the area, and at the same time, it does not need to introduce other media such as fuels, combustion aids, and flue gases, featuring system safety and high efficiency. At the same time, the setting of the heating chamber forms a large particle channel, effectively avoiding the problem that large particles coming out of the classification impeller directly enter the area where the heating chamber is located without passing through the collision area, resulting in a reduction in the classification efficiency of the classification wheel.

[0018] Furthermore, in the ultrafine powder preparation device of the present invention, the flared opening design at the upper end of the heating chamber plays a guiding role for the material to enter the classification impeller. The distance between the upper circular surface of the heating chamber and the classification impeller ensures that the gas and material in the heating chamber can smoothly enter the classification impeller under a small pressure drop. The diameter of the upper circular opening of the heating chamber is not greater than the diameter of the classification impeller to ensure that the large particles separated by the classification impeller do not fall into the heating chamber as much as possible.

[0019] Furthermore, in the ultrafine powder preparation device of the present invention, the electromagnetic induction coils are arranged in multiple groups. By activating one or several of them for electromagnetic induction, the temperature of the pulverized coal at the outlet is adjusted, effectively increasing the adjustment range and means of the temperature of the ultrafine pulverized coal and preventing the pyrolysis reaction from occurring due to overheating of the pulverized coal.

[0020] Furthermore, in the ultrafine powder preparation device of the present invention, the blocking convex structure in the heating chamber increases the residence time of the pulverized coal in the heating chamber, enabling the pulverized coal to be fully heated and enhancing the heat transfer effect.

[0021] Furthermore, in the ultrafine powder preparation device of the present invention, by using a water-cooled method for the electromagnetic induction coils, a first heat insulation layer is provided on the inner side of the coils, and a second heat insulation layer is provided on the outer side of the coils, ensuring that the operating temperature of the electromagnetic induction coils does not exceed the limit temperature, and at the same time avoiding the high-temperature damage and wear of the coils caused by large-particle high-temperature pulverized coal in the settling zone. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, which will help to understand the purpose and advantages of the present invention, wherein:

[0023] Figure 1 is a schematic structural diagram of a specific embodiment of the ultrafine powder preparation device of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The technical solutions of the present invention will be described clearly and completely below with reference to the accompanying drawings. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without any creative work shall fall within the protection scope of the present invention.

[0025] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0026] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0027] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] As Figure 1 shown is a specific embodiment of the ultrafine powder preparation device provided by the present invention, which is used to impact powder materials, such as combustible powder materials like pulverized coal or non-combustible powder materials like mineral fine powder, with a high-speed air flow to break them into ultrafine powders and output.

[0029] This embodiment takes the preparation of pulverized coal as an example to illustrate the specific structure of the preparation device. As Figure 1As shown in the figure, the ultrafine powder preparation device includes a crushing chamber 16, which is respectively provided with a collision zone, a heating zone and a classification zone from bottom to top; wherein, the collision zone has a feed port 8 installed on the side wall of the crushing chamber 16 and at least a pair of air flow nozzles 9 located below the feed port 8; specifically, the air flow nozzles 9 are supersonic nozzles, which introduce supersonic gas into the crushing chamber 16, so that the powder materials entering the crushing chamber 16 impact and collide with each other to further crush and form ultrafine powder; the heating zone has a heating chamber 3 with openings at both ends and an electromagnetic induction coil 6 wound around the outer side of the heating chamber 3; when an induced current is passed through the electromagnetic induction coil 6 through a wire 14, a strong alternating electromagnetic field is generated in the heating chamber 3. Under the action of the alternating electromagnetic field, eddy currents are generated in the heating chamber 3, and the heating chamber 3 is heated and rapidly heated up. After the powder crushed in the collision zone enters the heating zone, under the action of thermal radiation, the temperature of the powder rises sharply, and the free moisture in the powder quickly evaporates, resulting in secondary crushing of the powder and generating ultrafine powder with a smaller particle size. The smaller the particle size of the ultrafine powder, the more fully the minerals in the coal are dissociated, which provides favorable conditions for the subsequent separation and preparation of ultra-pure coal; at the same time, because the smaller the particle size of the ultrafine powder, the larger the specific surface area, it can reduce the consumption of acid and alkali in the subsequent deashing process. The classification zone has a classification wheel 2, which rotates at a high speed under the drive of a drive device 1 to classify the powder passing through the collision zone and the heating zone. The qualified ultrafine powder with a smaller particle size is discharged along the discharge port at the top to a conveying pipeline 12, and the unqualified powder with a larger particle size is discharged back into the crushing chamber 16, and falls along the area between the crushing chamber 16 and the heating chamber 3 under the action of its own gravity and the guiding action of the wall of the heating chamber 3 to the collision zone for collision and crushing again. Through multiple crushing in the collision zone and the heating zone, the ultrafine powder preparation efficiency of the preparation device can be improved; the heating chamber 3 can also isolate the unqualified powder screened by the classification wheel 2 from the powder collided in the collision zone, and improve the classification efficiency of the classification wheel 2.

[0030] Specifically, the heating chamber 3 is fixed to the inner side of the crushing chamber 16 through a plurality of support beams 13. In an optional implementation manner, the crushing chamber 16, the heating chamber 3 and the classification wheel 2 are coaxially arranged. Since the air flow nozzles 9 are arranged in pairs on the opposite sides of the crushing chamber 16, the collision center area is located in the area where the center line of the crushing chamber 16 is located. The heating chamber 3 and the classification wheel 2 are coaxially arranged with the crushing chamber 16, which can make the crushed powder concentrate and rise along the center of the crushing chamber 16 under the action of the flow field in the crushing chamber 16, with small air flow resistance and high crushing and classification efficiency.

[0031] The opening area on the upper side of the heating chamber 3 is smaller than the area of the classification wheel 2 to avoid as much as possible the problem that the unqualified powder screened by the classification wheel 2 directly enters the heating chamber 3 without experiencing another collision, resulting in a reduction in the classification efficiency of the classification wheel 2.

[0032] Specifically, in an alternative embodiment, the heating chamber 3 is integrally cylindrical with openings at both the upper and lower ends. The upper opening has a horn-shaped flaring structure, which ensures that the gas and materials in the heating chamber 3 can smoothly enter the classification wheel 2 with a relatively small pressure drop. The lower opening of the heating chamber 3 has a horn-shaped flaring structure, which ensures that the materials in the collision zone can smoothly enter the heating chamber 3 with a relatively small pressure drop.

[0033] Specifically, in an alternative embodiment, a number of blocking protrusion structures 5 are provided on the inner wall of the heating chamber 3, so that the pulverized coal materials entering the heating chamber 3 can have a longer residence time, and the heat radiation time of the heating chamber 3 wall on the pulverized coal is enhanced. Among them, the shape of the blocking protrusion structure 5 is not unique. For example, a baffle in the shape of an approximate herringbone or an annular louver structure can be used. The upper surface of the blocking protrusion is an inclined surface to avoid the problem of powder accumulation on the surface of the blocking protrusion. The number of blocking protrusion structures 5 can be arranged in a regular or irregular manner.

[0034] The electromagnetic induction coil 6 is a water-cooled electromagnetic induction coil 6. The water-cooled electromagnetic induction coil 6 is an electromagnetic induction coil 6 accompanied by a water-cooling hose, that is, the water-cooling hose is arranged outside the electromagnetic induction coil 6 for cooling. A first heat-insulating layer 4 is provided between the electromagnetic induction coil 6 and the heating chamber 3. The surface temperature of the first heat-insulating layer 4 in the working state is not higher than 60 °C. The first heat-insulating layer 4 prevents the high-temperature heating chamber 3 under electromagnetic induction from scalding and damaging the electromagnetic induction coil 6; the first heat-insulating layer 4 can be selected from aluminosilicate fiber boards, high-temperature-resistant alumina aerosol materials, alumina fiber boards, etc. A second heat-insulating layer 7 is provided outside the electromagnetic induction coil 6. The second heat-insulating layer 7 is made of heat-insulating materials such as rock wool and slag wool that can withstand 350 °C. A wear-resistant metal layer is added to the outer surface of the second heat-insulating layer 7 to prevent the high-temperature large-particle powder approaching 300 °C falling from the classification area from causing wear and high-temperature scalding damage to the electromagnetic induction coil 6.

[0035] In an alternative embodiment, the electromagnetic induction coils 6 are arranged in multiple groups. Since pyrolysis reactions occur when the pulverized coal temperature is higher than 300 °C, it is necessary to control the temperature of the pulverized coal after passing through the heating chamber 3 to not exceed 300 °C. The multiple-group arrangement of the electromagnetic induction coils 6 can adjust the number of groups of the electromagnetic induction coils 6 according to the temperature parameter of the pulverized coal at the outlet of the crushing chamber 16. For example, the crushing chamber 16 is provided with a discharge port on the upper side of the classification area, the discharge port is communicated with the conveying pipeline 12, and a temperature sensor 11 is arranged on the conveying pipeline 12. The electromagnetic induction circuit where the electromagnetic induction coils 6 are located is controlled to be turned on or off according to the detection signal of the temperature sensor 11 to control the operation of different groups of electromagnetic induction coils 6. For example, when the temperature sensor 11 detects that the temperature of the pulverized coal in the conveying pipeline 12 is higher than the first threshold, some of the electromagnetic induction coils 6 are controlled to stop being energized, reducing the heating time of the pulverized coal passing through the heating chamber 3 and lowering the outlet temperature, thereby adjusting the outlet pulverized coal within a reasonable temperature range. In addition, the outlet pulverized coal temperature can also be adjusted by adjusting the magnitude of the induction current passing through the induction coil.

[0036] Specifically, as Figure 1 shown, the relationship between the distance L between the lower side surface of the heating chamber 3 and the center line of the air flow nozzle 9 and the diameter D of the crushing chamber 16 in the area where the air flow nozzle 9 is located is: L ≥ 0.6D, which can prevent the heating chamber 3 from interfering with the collision flow field too low, resulting in incomplete collision. The above installation position of the heating chamber 3 ensures that the powder particles effectively collide in the collision area, further improving the crushing efficiency of the device.

[0037] Specifically, the upper side surface of the heating chamber 3 is as close as possible to the lower end surface of the classification wheel 2 to reduce the gap between the heating chamber 3 and the classification wheel 2, preventing large-particle pulverized coal with unqualified particle size centrifugally separated by the classification wheel 2 from entering the heating chamber 3 through the gap between the heating chamber 3 and the classification wheel 2.

[0038] Specifically, the crushing chamber 16 further includes a waste discharge area located below the air flow nozzle 9. The bottom of the waste discharge area is provided with a waste outlet 17, and the waste outlet 17 is funnel-shaped. Unqualified waste is discharged through the waste outlet 17.

[0039] Obviously, the above embodiments are only examples clearly described and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. An ultrafine powder preparation device, characterized in that, Comprising: A crushing chamber, which is respectively provided with a collision zone, a heating zone and a classification zone from bottom to top; The collision zone has a feed inlet installed on the side wall of the crushing chamber and at least a pair of air flow nozzles located below the feed inlet; The heating zone has a heating chamber with openings at both ends and an electromagnetic induction coil wound around the outside of the heating chamber; The classification zone has a classification wheel for classifying the powder passing through the collision zone and the heating zone.

2. The ultra-fine powder preparation device according to claim 1, characterized in that, The crushing chamber, the heating chamber and the classification wheel are coaxially arranged, and the opening area on the upper side of the heating chamber is smaller than the area of the classification wheel.

3. An ultrafine powder preparation device according to claim 1, characterized in that, The heating chamber is integrally cylindrical, and its upper opening and / or lower opening has a horn-shaped flared structure.

4. An ultrafine powder preparation device according to claim 1, characterized in that The inner wall of the heating chamber is provided with a number of blocking convex structures, and the upper surface of the blocking convex structure is an inclined plane or an upwardly convex arc surface.

5. An ultrafine powder preparation device according to claim 1, characterized in that The electromagnetic induction coil is a water-cooled electromagnetic induction coil, a first heat insulation layer is arranged between the electromagnetic induction coil and the heating chamber, and a second heat insulation layer is arranged outside the electromagnetic induction coil.

6. An ultrafine powder preparation device according to claim 5, characterized in that, A wear-resistant metal layer is provided on the outside of the second heat insulation layer.

7. An ultrafine powder preparation device according to claim 1, characterized in that, The electromagnetic induction coils are arranged in multiple groups, and the multiple groups of electromagnetic induction coils form multiple groups of electromagnetic induction circuits.

8. An ultrafine powder preparation device according to claim 1, characterized in that, The relationship between the distance L between the lower side surface of the heating chamber and the center line of the air flow nozzle and the diameter D of the crushing chamber in the area where the air flow nozzle is located is: L≥0.6D.

9. An ultrafine powder preparation device according to claim 1, characterized in that, The crushing chamber further includes a waste discharge area located below the air flow nozzle, and a waste outlet is provided at the bottom of the waste discharge area.

10. The ultrafine powder preparation device according to claim 9, characterized in that, The crushing chamber is provided with a discharge port above the classification zone, the discharge port is communicated with a conveying pipeline, and a temperature sensor is arranged on the conveying pipeline, and the electromagnetic induction circuit where the electromagnetic induction coil is located is controlled according to the detection signal of the temperature sensor.

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