Device and method for adjusting air and powder concentration at outlet of medium-speed coal mill

Abstract

The embodiment of the invention provides a medium-speed coal mill outlet air powder concentration adjusting device and method, and the device comprises a shell which is provided with a material opening communicating with the interior of the shell; the feeding and discharging structure is arranged at the material opening of the shell, and the feeding and discharging structure is provided with a pulverized coal channel communicated with the interior of the shell; the powder outlet pipe is arranged corresponding to the powder inlet and outlet structure, and the powder outlet pipe is communicated with the pulverized coal channel of the material inlet and outlet structure; and the adjustable structure is arranged corresponding to the pulverized coal outlet pipe, and the adjustable structure is configured to adjust the through-flow sectional area of the pulverized coal outlet pipe so as to adjust the mass flow of pulverized coal flowing in the pulverized coal outlet pipe. According to the application, a direct intervention mode of changing the through-flow sectional area of the pulverized coal outlet pipe by adopting a mechanical adjustable structure is adopted, the problem of nonlinear response existing in traditional air door adjustment is solved, and the pulverized coal mass flow control precision can be effectively improved. In addition, the adjusting device has the advantages of being simple in structure, flexible in adjustment and high in adaptability, and the pulverized coal flow distribution uniformity of the pulverized coal outlet pipe can be rapidly optimized.

Description

Technical Field

[0001] The embodiments disclosed herein belong to the technical field of pulverizing systems for thermal power units, specifically relating to a device and method for regulating the concentration of pulverized coal at the outlet of a medium-speed coal mill. Background Technology

[0002] In existing coal-fired power plants, medium-speed coal mills are widely used for pulverized coal preparation. The mill outlet delivers pulverized coal to the burner through multiple outlet pipes. However, due to the non-uniformity of the gas-solid mixture at the outlet of the dynamic separator and limitations in equipment layout, uneven pulverized coal mass flow distribution often occurs among the multiple outlet pipes. This problem can cause boiler combustion deviations, localized slagging, and NOx emissions. x A series of operational problems, including increased emissions.

[0003] Existing technologies mainly rely on methods such as adjusting secondary air, adding baffles, or optimizing pipeline routing for compensation. However, these methods are complex to construct or have strong adjustment lag, making them difficult to adapt to complex operating conditions such as frequent changes in coal type and rapid load switching in actual operation.

[0004] Therefore, it is necessary to design a coal powder distribution and regulation device and method that is simple in structure, flexible in adjustment, and highly adaptable, so as to achieve rapid optimization of the coal powder flow distribution in the coal powder outlet pipe. Summary of the Invention

[0005] The embodiments disclosed herein aim to at least solve one of the technical problems existing in the prior art, and provide a device and method for regulating the outlet air-coal concentration of a medium-speed coal mill.

[0006] A first aspect of the embodiments of this disclosure provides a device for regulating the concentration of pulverized coal at the outlet of a medium-speed coal mill, comprising:

[0007] A housing having a feed inlet communicating with its interior;

[0008] The material inlet and outlet structure is disposed at the material inlet of the shell and has a coal powder channel communicating with the interior of the shell.

[0009] A powder outlet pipe is provided corresponding to the powder inlet and outlet structure, and the powder outlet pipe is connected to the coal powder channel of the powder inlet and outlet structure;

[0010] An adjustable structure is provided corresponding to the pulverized coal outlet pipe. The adjustable structure is configured to adjust the flow cross-sectional area of ​​the pulverized coal outlet pipe to adjust the mass flow rate of pulverized coal flowing in the pulverized coal outlet pipe.

[0011] Optionally, the adjustable structure includes a baffle that is rotatably connected to the inner wall of the pulverized coal channel and covers the opening of the pulverized coal outlet pipe.

[0012] Optionally, the baffle is circular and is coaxially arranged with the powder outlet pipe.

[0013] Optionally, the area of ​​the baffle is set to half the cross-section of the powder outlet pipe.

[0014] Optionally, the deflectable angle range of the baffle is set to -90° to +90°, wherein when the baffle is adjusted to the 0° position, the baffle is parallel to the cross-section of the powder outlet pipe.

[0015] Optionally, the feeding and discharging structure is provided with a coal dropping channel communicating with the interior of the shell, and the adjusting device further includes a coal dropping pipe, which passes through the coal dropping channel and communicates with the interior of the shell.

[0016] Furthermore, it also includes: a grinding roller, which is disposed inside the housing and is used to grind the raw coal.

[0017] Furthermore, it also includes: an air ring, which is disposed within the housing and configured to provide primary air for blowing pulverized coal.

[0018] Furthermore, it also includes: a separator and an inner cone, the separator being disposed within the housing and used to separate coal powder within the housing; the inner cone being disposed within the housing and configured to guide the separated coal powder to the powder outlet pipe.

[0019] A second aspect of the embodiments of this disclosure provides a method for adjusting the pulverized coal concentration at the outlet of a medium-speed coal mill, comprising:

[0020] Real-time monitoring of pulverized coal mass flow rate in each pulverized coal outlet pipe;

[0021] When the coal powder distribution ratio needs to be increased in the coal powder outlet pipe, the adjustable structure corresponding to the coal powder outlet pipe is controlled to deflect in the counterclockwise direction by a set angle, so as to enhance the coal powder conveying capacity of the downstream pipeline by changing the flow field distribution in the inlet area of ​​the coal powder outlet pipe.

[0022] When the target pulverized coal outlet pipe needs to reduce the pulverized coal distribution ratio, the adjustable structure corresponding to the pulverized coal outlet pipe is controlled to deflect clockwise by a set angle, so as to weaken the pulverized coal conveying kinetic energy by generating a local cyclone effect.

[0023] Based on the coal powder distribution deviation of each coal powder outlet pipe, the coordinated deflection angle combination of multiple adjustable structures is dynamically adjusted to achieve a balanced distribution of coal powder concentration at the outlet.

[0024] The beneficial effects of the embodiments of this disclosure include:

[0025] This application employs a direct intervention method that changes the cross-sectional area of ​​the pulverized coal outlet pipe using a mechanically adjustable structure, overcoming the nonlinear response problem inherent in traditional damper regulation and effectively improving the accuracy of pulverized coal mass flow control. Furthermore, the regulating device of this application features a simple structure, flexible adjustment, and strong adaptability, and can rapidly optimize the uniformity of pulverized coal flow distribution in the outlet pipe. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a medium-speed coal mill outlet air-coal concentration regulating device according to an embodiment of the present disclosure;

[0027] Figure 2 This is a partial structural schematic diagram of a medium-speed coal mill outlet air-coal concentration regulating device according to an embodiment of the present disclosure.

[0028] Figure 3 This is a partial structural schematic diagram of a medium-speed coal mill outlet air-coal concentration regulating device according to another embodiment of the present disclosure.

[0029] Figure 4 This is a partial structural schematic diagram of a medium-speed coal mill outlet air-coal concentration regulating device according to another embodiment of the present disclosure.

[0030] Figure 5 This is a schematic flowchart of a method for adjusting the outlet air-coal concentration of a medium-speed coal mill, according to another embodiment of this disclosure.

[0031] In the diagram, 1 is the shell; 2 is the inlet / outlet structure; 3 is the powder outlet pipe; 4 is the adjustable structure; 5 is the coal drop pipe; 6 is the grinding roller; 7 is the air ring; 8 is the separator; and 9 is the inner cone. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] The embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The detailed descriptions and accompanying drawings of the following embodiments are used to exemplarily illustrate the principles of this application, but should not be used to limit the scope of this application; that is, this application is not limited to the described embodiments. In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicating orientation or positional relationships are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0034] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific circumstances.

[0035] like Figure 1-4 As shown, a medium-speed coal mill outlet air-coal concentration regulating device is provided. The concentration regulating device includes a shell 1, an inlet / outlet structure 2, a powder outlet pipe 3, and an adjustable structure 4.

[0036] The housing 1 has a material inlet communicating with its interior, and the material inlet / outlet structure 2 is disposed at the material inlet of the housing 1. The material inlet / outlet structure 2 has a coal powder channel communicating with the interior of the housing 1.

[0037] The powder outlet pipe 3 is correspondingly arranged with the powder inlet and outlet structure, and the powder outlet pipe 3 is connected to the coal powder channel of the material inlet and outlet structure 2. The adjustable structure 4 is correspondingly arranged with the powder outlet pipe 3. The adjustable structure 4 is configured to adjust the flow cross-sectional area of ​​the powder outlet pipe 3 in order to adjust the coal powder mass flow rate flowing in the powder outlet pipe 3.

[0038] This application employs a direct intervention method—using a mechanically adjustable structure 4 to change the flow cross-sectional area of ​​the pulverized coal outlet pipe 3—overcoming the nonlinear response problem inherent in traditional damper regulation and effectively improving the accuracy of pulverized coal mass flow control. Furthermore, the regulating device of this application features a simple structure, flexible adjustment, and strong adaptability, and can rapidly optimize the uniformity of pulverized coal flow distribution in the outlet pipe 3.

[0039] In some embodiments, the adjustable structure 4 includes a baffle that is rotatably connected to the inner wall of the pulverized coal channel and covers the opening of the pulverized coal outlet pipe 3.

[0040] In one embodiment, the baffle is connected to the wall of the powder outlet pipe 3 via a bearing structure or a rotating mechanism.

[0041] In some embodiments, the baffle is circular and is coaxially arranged with the powder outlet pipe 3.

[0042] In some embodiments, the area of ​​the baffle is set to half the cross-sectional area of ​​the powder outlet pipe 3.

[0043] In some embodiments, the deflectable angle range of the baffle is set to -90° to +90°, wherein when the baffle is adjusted to the 0° position, the baffle is parallel to the cross-section of the powder outlet pipe 3.

[0044] In some embodiments, the feeding / discharging structure 2 is provided with a coal dropping channel communicating with the interior of the housing 1, and the adjusting device further includes a coal dropping pipe 5, which passes through the coal dropping channel and communicates with the interior of the housing 1.

[0045] In some embodiments, the adjusting device further includes a grinding roller 6 disposed within the housing 1 for grinding the raw coal.

[0046] In some embodiments, the regulating device further includes an air ring 7 disposed within the housing 1, the air ring 7 being configured to provide primary air for blowing pulverized coal.

[0047] In some embodiments, the regulating device further includes a separator 8 and an inner cone 9. The separator 8 is disposed within the housing 1 and is used to separate the coal powder within the housing 1. The inner cone 9 is disposed within the housing 1 and is configured to guide the separated coal powder to the powder outlet pipe 3.

[0048] In some embodiments, separator 8 includes a dynamic separator and a static separator.

[0049] The present invention provides a coal powder concentration adjustment device, which can guide the coal powder flow direction by means of an adjustable baffle without changing the overall structure of the coal powder outlet pipe 3, thereby achieving a balanced distribution of coal powder flow among multiple coal powder outlet pipes 3.

[0050] In a specific example, the air-coal concentration regulating device includes components such as: coal outlet pipe 3, adjustable baffle, coal drop pipe 5, dynamic separator, static separator, and inner cone 9.

[0051] There are four pulverized coal outlet pipes 3, which are evenly arranged circumferentially in the top area of ​​the coal mill by welding, to supply pulverized coal to the combustion system.

[0052] The baffle is connected to the wall of the powder outlet pipe 3 via a bearing structure or a rotating mechanism to achieve adjustable rotation. The rotating mechanism includes an external drive device (electric actuator), which drives the baffle to deflect around the cross-section of the powder outlet pipe 3. The deflection angle range is -90° to +90° to create controllable local airflow disturbance.

[0053] The coal drop pipe 5 is located at the upper center of the coal mill and serves as the channel for pulverized coal to fall and enter the separator 8. Below it, a dynamic separator and a static separator are connected in sequence, forming a separation channel for coarse and fine pulverized coal particles. The separated pulverized coal then enters the corresponding powder outlet pipe 3 via the separator 8.

[0054] The inner cone 9 is located at the bottom of the separator 8 and is connected to the static separator by bolts. It is used to guide the separated coal powder to be transported to the circumferentially distributed powder outlet pipe 3, while enhancing the gas-solid separation effect.

[0055] Specifically, the device includes a circular baffle installed in the inlet area of ​​the coal mill outlet pipe 3. The center of the baffle coincides with the center of the inlet cross-section of the outlet pipe 3, and the area of ​​the baffle is half of the cross-sectional area of ​​the outlet pipe 3, with a thickness of 20mm.

[0056] Furthermore, when the baffle is placed vertically, its plane is parallel to the plane containing the central axis of the coal mill.

[0057] Figure 2 With the baffle in a vertical position, this is the baseline operating condition, and the pulverized coal flow rates of the four pulverized coal outlet pipes are relatively uneven.

[0058] Figure 4 With the baffle offset counterclockwise by 45°, and the baffle facing the wind, the results show that the coal powder flow rate of the downstream coal outlet pipe 3 increases significantly, while the coal powder flow rate of this coal outlet pipe 3 decreases significantly. This indicates that the baffle has a good deflection and guiding function, which can guide the gas-solid mixture flow in a specific direction.

[0059] Figure 3 With the baffle rotated 45° clockwise, the baffle is positioned leeward.

[0060] The flow rate of pulverized coal in the downstream pulverized coal outlet pipe 3 decreased significantly, while the flow rate in the pulverized coal outlet pipe 3 increased.

[0061] In summary, the device of the present invention can effectively regulate the coal powder distribution among multiple coal powder outlet pipes 3 of the coal mill, and has the advantages of rapid adjustment, simple structure and easy maintenance.

[0062] refer to Figure 5 A second aspect of the embodiments of this disclosure provides a method for adjusting the pulverized coal concentration at the outlet of a medium-speed coal mill, comprising:

[0063] S101. Real-time monitoring of the coal powder mass flow rate of each coal powder outlet pipe 3.

[0064] S102. When the coal powder distribution ratio of the coal powder outlet pipe 3 needs to be increased, the adjustable structure 4 corresponding to the coal powder outlet pipe 3 is controlled to deflect in the counterclockwise direction by a set angle, so as to enhance the coal powder conveying capacity of the downstream pipeline by changing the flow field distribution in the inlet area of ​​the coal powder outlet pipe 3.

[0065] S103. When the target pulverized coal outlet pipe 3 needs to reduce the pulverized coal distribution ratio, the adjustable structure 4 corresponding to the pulverized coal outlet pipe 3 is controlled to deflect in a clockwise direction by a set angle, so as to weaken the pulverized coal conveying kinetic energy by generating a local cyclone effect.

[0066] S104. Based on the coal powder distribution deviation of each coal powder outlet pipe 3, dynamically adjust the coordinated deflection angle combination of multiple adjustable structures 4 to achieve a balanced distribution of coal powder concentration at the outlet.

[0067] In this application, a baffle is installed in the inlet section of a certain pulverized coal outlet pipe 3. By adjusting the angle of the baffle, a local airflow disturbance is created to regulate the pulverized coal mass flow rate of the pipe and its downstream pulverized coal outlet pipe 3. Specifically, when the baffle is offset counterclockwise, it increases the pulverized coal flow rate of its downstream pulverized coal outlet pipe 3, and when the baffle is offset clockwise, it decreases the pulverized coal flow rate of its downstream pulverized coal outlet pipe 3.

[0068] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A device for regulating the concentration of pulverized coal at the outlet of a medium-speed coal mill, characterized in that, include: A housing having a feed inlet communicating with its interior; The material inlet and outlet structure is disposed at the material inlet of the shell and has a coal powder channel communicating with the interior of the shell. A powder outlet pipe is provided corresponding to the powder inlet and outlet structure, and the powder outlet pipe is connected to the coal powder channel of the powder inlet and outlet structure; An adjustable structure is provided corresponding to the pulverized coal outlet pipe. The adjustable structure is configured to adjust the flow cross-sectional area of ​​the pulverized coal outlet pipe to adjust the mass flow rate of pulverized coal flowing in the pulverized coal outlet pipe.

2. The adjusting device according to claim 1, characterized in that, The adjustable structure includes a baffle plate, which is rotatably connected to the inner wall of the pulverized coal channel and covers the opening of the pulverized coal outlet pipe.

3. The adjusting device according to claim 2, characterized in that, The baffle is circular and is coaxially arranged with the powder outlet pipe.

4. The adjusting device according to claim 2, characterized in that, The area of ​​the baffle is set to half the cross-section of the powder outlet pipe.

5. The adjusting device according to claim 2, characterized in that, The deflection angle range of the baffle is set to -90° to +90°, wherein when the baffle is adjusted to the 0° position, the baffle is parallel to the cross-section of the powder outlet pipe.

6. The adjusting device according to claim 1, characterized in that, The feeding and discharging structure is provided with a coal dropping channel that communicates with the inside of the shell. The regulating device also includes a coal dropping pipe that passes through the coal dropping channel and communicates with the inside of the shell.

7. The adjusting device according to claim 1, characterized in that, Also includes: A grinding roller, which is disposed inside the housing, is used to grind raw coal.

8. The adjusting device according to claim 1, characterized in that, Also includes: An air ring is disposed within the housing and configured to provide primary air for blowing pulverized coal.

9. The adjusting device according to claim 1, characterized in that, Also includes: A separator and an inner cone, wherein the separator is disposed within the housing and is used to separate coal powder within the housing; The inner cone is disposed within the housing and is configured to guide the separated coal powder to the powder outlet pipe.

10. A method for adjusting the concentration of pulverized coal at the outlet of a medium-speed coal mill, characterized in that, include: Real-time monitoring of pulverized coal mass flow rate in each pulverized coal outlet pipe; When the coal powder distribution ratio needs to be increased in the coal powder outlet pipe, the adjustable structure corresponding to the coal powder outlet pipe is controlled to deflect in the counterclockwise direction by a set angle, so as to enhance the coal powder conveying capacity of the downstream pipeline by changing the flow field distribution in the inlet area of ​​the coal powder outlet pipe. When the target pulverized coal outlet pipe needs to reduce the pulverized coal distribution ratio, the adjustable structure corresponding to the pulverized coal outlet pipe is controlled to deflect clockwise by a set angle, so as to weaken the pulverized coal conveying kinetic energy by generating a local cyclone effect. Based on the coal powder distribution deviation of each coal powder outlet pipe, the coordinated deflection angle combination of multiple adjustable structures is dynamically adjusted to achieve a balanced distribution of coal powder concentration at the outlet.

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