Medium speed coal pulverizer separator based on airflow deagglomeration dispersion back to powder

Abstract

The medium-speed coal powder separator based on airflow deagglomeration and dispersion and powder returning includes a separator, a coal falling pipe penetrating through the separator, a powder returning hopper arranged between the separator and the coal falling pipe, and is characterized in that: the medium-speed coal powder separator further includes an air cavity fixed on the coal falling pipe and close to a discharge port of the powder returning hopper and a gas guide pipe for guiding high-pressure gas into the air cavity, and the air cavity shoots the high-pressure gas outward to form an impinging flow field below the discharge port of the powder returning hopper with the introduction of the high-pressure gas. The utility model utilizes the impinging flow field to form active deagglomeration and dispersion of the returned powder, efficiently separates fine powder from coarse powder, prevents the fine powder from being wrapped and aggregated with the coarse powder, realizes the dispersion and re-separation of the returned powder, improves the powder separation rate, effectively reduces the circulating ratio and the coal grinding power consumption of the coal mill, and improves the economy and the output space of the coal mill.

Description

Technical Field

[0001] This utility model relates to a medium-speed coal pulverizer based on airflow deagglomeration, dispersion and return of pulverized coal, belonging to the technical field of coarse powder separators for medium-speed coal mills. Background Technology

[0002] In thermal power plants, medium-speed coal mills are the core equipment of the pulverizing system, grinding raw coal into pulverized coal of a suitable fineness for boiler combustion. The performance of the coal mill's separation system directly affects the fineness of the pulverized coal, the mill's output, and power consumption. Currently, medium-speed coal mills generally use coarse powder separators to separate the ground pulverized coal into coarse and fine particles. The qualified fine pulverized coal is carried to the furnace for combustion by primary air, while the coarse pulverized coal (called "return powder") falls along the inner wall of the separator and returns to the grinding disc for regrinding via the return powder hopper. However, the existing technology has the following problems: 1. Fine powder entrained in the returned coal: Due to the complexity of the gas-solid two-phase flow and the limitations of the initial separation efficiency of the separator, the returned coal often contains a large amount of coal powder that has reached the qualified fineness, which is often entrained, mixed, or agglomerated. This fine powder returns to the grinding disc along with the coarse powder, resulting in the waste of effective coal powder.

[0003] 2. High circulation ratio and high coal grinding power consumption: The above-mentioned ineffective fine powder returned to the grinding disc increases the circulating load of the coal mill and the unnecessary grinding power consumption, resulting in an increase in the circulation ratio of the coal mill, an increase in coal grinding power consumption, and a reduction in the economic efficiency and output capacity of the coal mill.

[0004] While existing technologies have developed schemes that guide the returned powder to the main airflow for secondary separation by setting up a flow guiding structure, these schemes mainly rely on gravity flow and the main airflow to carry the powder. However, the qualified fine and coarse powder in the returned powder is in an agglomerated state, so the effect of secondary separation by the main airflow is limited, and the improvement effect on the circulation ratio and coal grinding power consumption is not significant. Utility Model Content

[0005] The medium-speed coal pulverizer based on airflow deagglomeration and dispersion of returned coal powder provided by this utility model utilizes the impact flow field to actively deagglomerate and disperse the returned coal powder, efficiently separating fine powder from coarse powder, preventing fine powder from being wrapped and agglomerated together, realizing the dispersion and re-separation of returned coal powder, improving the returned coal powder separation rate, effectively reducing the circulation ratio and coal mill power consumption, and improving the economy and output capacity of the coal mill.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A medium-speed coal pulverizer based on airflow deagglomeration and dispersion for powder return includes a separator, a coal chute penetrating the separator, and a powder return hopper disposed between the separator and the coal chute. Its characteristic feature is that it further includes an air chamber fixed to the coal chute and close to the discharge port of the powder return hopper, and a guide pipe for introducing high-pressure gas into the air chamber. The air chamber, with the introduction of high-pressure gas, ejects the high-pressure gas outwards, forming an impact flow field below the discharge port of the powder return hopper.

[0007] Preferably, the air chamber is annular in shape, and the outer diameter of the air chamber is smaller than the inner diameter of the discharge port of the return powder hopper. An air outlet is provided on the air chamber to eject high-pressure gas outward.

[0008] The coal powder separator according to the claim is characterized in that: the air outlet is opened on the outer wall of the air chamber and located above the air guide pipe, and the air outlet is evenly distributed in multiple layers along the circumference of the air chamber.

[0009] Preferably, each air outlet is equipped with a nozzle.

[0010] Preferably, the angle between the axis of the nozzle and the tangent of the outer circumference of the air chamber is less than 90 degrees, and the nozzle is tilted upward.

[0011] Preferably, an airlock is installed on the discharge port of the powder return hopper.

[0012] The beneficial effects of this utility model are: This utility model discloses a medium-speed coal pulverizer separator based on airflow deagglomeration and dispersion of returned coal powder. The air chamber is located near the discharge port of the returned coal hopper. High-pressure gas is introduced into the air chamber through an air guide pipe. The high-pressure gas is ejected from the air chamber and forms an impact flow field below the returned coal discharge port. The returned coal powder, upon exiting the discharge port, encounters the impact flow field. Under the combined action of the shear force, centrifugal force, and collision force of the airflow, the coarse and fine powder particles that are clustered together in the returned coal powder are deagglomerated and dispersed, allowing the fine powder to actively separate from the coarse powder. The separated fine powder flows along the airflow path of the separator, while the coarse powder falls onto the grinding bowl below the separator for further grinding. By utilizing the impact flow field to actively deagglomerate and disperse the returned coal powder, the fine and coarse powders are efficiently separated, preventing them from being wrapped up and agglomerated together. This achieves the dispersion and re-separation of the returned coal powder, improving the returned coal separation rate, effectively reducing the circulation ratio and coal grinding power consumption of the coal mill, and enhancing the economy and output potential of the coal mill. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a medium-speed coal pulverizer separator based on airflow deagglomeration and dispersion for powder return in a specific implementation.

[0014] Figure 2 for Figure 1 A magnified view of a portion of the image.

[0015] Figure 3 for Figure 2 Sectional view along the AA direction.

[0016] Figure 4 This is a schematic diagram of the air-powder flow path in a medium-speed pulverized coal separator based on airflow deagglomeration and dispersion return. Detailed Implementation

[0017] The following is combined with Figures 1-4The embodiments of this utility model will be described in detail below.

[0018] A medium-speed coal pulverizer based on airflow deagglomeration and dispersion for powder return includes a separator 1, a coal drop pipe 2 penetrating the separator, and a powder return hopper 3 disposed between the separator 1 and the coal drop pipe 2. The invention is characterized by further including an air chamber 4 fixed to the coal drop pipe 2 and near the discharge port of the powder return hopper 3, and a guide pipe 5 for introducing high-pressure gas into the air chamber 4. The air chamber 4, with the introduction of high-pressure gas, ejects the high-pressure gas outward, forming an impact flow field below the discharge port of the powder return hopper.

[0019] The medium-speed coal pulverizer separator based on airflow deagglomeration and dispersion of returned powder described above has an air chamber 4 located near the discharge port of the returned powder hopper 3. High-pressure gas is introduced into the air chamber 4 through the air guide pipe 5. The high-pressure gas is ejected outward from the air chamber 4, forming an impact flow field below the returned powder discharge port. The returned powder, upon exiting from the discharge port, encounters the impact flow field. Under the combined action of the airflow shear force, centrifugal force, and collision force, the coarse and fine powders that are clustered together in the returned powder are deagglomerated and dispersed, allowing the fine powder in the returned powder to actively separate from the coarse powder. The separated fine powder flows along the airflow path of the separator, while the coarse powder falls onto the grinding bowl below the separator for further grinding. By utilizing the impact flow field to actively deagglomerate and disperse the returned powder, the fine and coarse powders are efficiently separated, preventing them from being wrapped up and clustered together. This achieves the dispersion and re-separation of the returned powder, improving the returned powder separation rate, effectively reducing the circulation ratio and coal mill power consumption, and enhancing the economy and output capacity of the coal mill.

[0020] The air chamber 4 is annular in shape, and its outer diameter is smaller than the inner diameter of the discharge port of the return powder hopper 3. An outlet 41 is provided on the air chamber to eject high-pressure gas outward. As shown in the figure, the air chamber 4 is close to the discharge port of the return powder hopper 3. The high-pressure gas in the air chamber 4 is ejected outward to form an impact flow field. When the return powder is discharged from the discharge port of the return powder hopper 3, it enters the impact flow field. The return powder is impacted by the high speed of the impact flow, and the agglomerated fine powder in the return powder is separated and discharged upward with the air-powder flow path in the separator. The formed impact flow field is used to disperse and separate the return powder, avoiding fine powder being trapped in coarse powder and falling with the coarse powder.

[0021] The air outlet 41 is located on the outer wall of the air chamber and above the air guide pipe, with multiple layers of outlets evenly distributed around the circumference of the air chamber 4. The air outlet 41 can be a pointed nozzle that shoots outwards, or it can be a square or round hole on the air chamber. The air outlet 41 is located above the air guide pipe 5 and is closer to the powder discharge port of the powder return hopper 3, ensuring that the returned powder discharged from the powder return hopper 3 immediately encounters the formed impact flow field. The multiple layers of air outlets 41 evenly distributed around the circumference of the air chamber increase the airflow density of the impact flow field, enhance the shear force, centrifugal force, and collision force experienced by the returned powder in the impact flow field, improve the reliability of the active deagglomeration and dispersion of the returned powder, and ensure efficient separation of fine powder from coarse powder.

[0022] Each outlet is equipped with a nozzle 6. High-pressure gas is sprayed through the nozzle 6 to increase the impact intensity of the impact flow field on the returned powder, further improving the reliability of the active deagglomeration and dispersion of the returned powder, and ensuring efficient separation of fine powder from coarse powder.

[0023] The angle θ between the axis of the nozzle 6 and the tangent of the outer circumference of the air chamber 4 is less than 90 degrees, and the nozzle 6 is tilted upwards. The simultaneous ejection of high-pressure gas from multiple nozzles 6 creates a high-speed rotating impact flow field around the outer circumference of the air chamber 4. The upward tilt of the nozzles 6 causes the impact flow field to rotate upwards, sending the dispersed and separated fine powder into the air-powder flow path of the separator, ensuring that the fine powder separated in the return powder will move upwards along the air-powder flow path.

[0024] The discharge port of the return powder hopper 3 is equipped with an air lock 7. The air lock 7 prevents the high-pressure gas ejected from the nozzle 6 from entering the return powder hopper 3 from the discharge port, ensuring that the return powder hopper 3 can discharge material normally without being affected by the impact flow field.

[0025] The technical solutions of the embodiments of this utility model have been fully described above with reference to the accompanying drawings. It should be noted that the described embodiments are only a part of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

Claims

1. A medium-speed coal pulverizer based on airflow deagglomeration and dispersion for powder return, comprising a separator, a coal chute penetrating the separator, and a powder return hopper disposed between the separator and the coal chute, characterized in that: It also includes an air chamber fixed on the coal chute and close to the discharge port of the return powder hopper, and a gas guide pipe that introduces high-pressure gas into the air chamber. As the high-pressure gas is introduced, the air chamber ejects the high-pressure gas outward to form an impact flow field below the discharge port of the return powder hopper.

2. The medium-speed coal pulverizer separator based on airflow deagglomeration and dispersion for powder return according to claim 1, characterized in that: The air chamber is annular in shape, and its outer diameter is smaller than the inner diameter of the discharge port of the return powder hopper. An outlet is provided on the air chamber to eject high-pressure gas outward.

3. The pulverized coal separator according to claim 2, characterized in that: The air outlet is located on the outer wall of the air chamber and above the air guide tube, and the air outlet is evenly distributed in multiple layers along the circumference of the air chamber.

4. The medium-speed coal pulverizer based on airflow deagglomeration and dispersion for powder return as described in claim 3, characterized in that: Each air outlet is equipped with a nozzle.

5. The medium-speed coal pulverizer separator based on airflow deagglomeration and dispersion for powder return according to claim 4, characterized in that: The angle between the axis of the nozzle and the tangent of the outer circumference of the air chamber is less than 90 degrees, and the nozzle is tilted upward.

6. The medium-speed coal pulverizer based on airflow deagglomeration and dispersion for powder return as described in claim 4, characterized in that: An airlock is installed on the discharge port of the powder return hopper.

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