A primary air volume distribution device for coal mill inlet

Abstract

The present invention relates to a primary air volume distribution device for the inlet of a coal mill, comprising a pipeline system connected to the inlet of the coal mill, the pipeline system comprising a hot primary air duct, a cold primary air duct, a first branch pipe, and a second branch pipe, one end of the first branch pipe is connected to the hot primary air duct, and the other end is connected to the inlet of the coal mill, one end of the second branch pipe is connected to the cold primary air duct, and the other end is connected to the first branch pipe, the device also includes a wind gathering component for increasing the air volume, and a flow guide component for regularizing the air flow, the wind gathering component is a wind gathering pipe with a pipe diameter at one end larger than the pipe diameter at the other end, and the flow guide component is an arc-shaped guide plate. The present invention increases the inlet air volume of the coal mill that lacks air by arranging the wind gathering component and the flow guide component, realizes the uniform distribution of the primary air flow at the inlet of each coal mill, has good applicability, optimizes the flow field in the primary air duct, improves the primary air flow distribution, and reduces the resistance in the primary air duct, thereby reducing the power consumption of the fan.

Description

Technical Field

[0001] The invention relates to the field of primary air flow distribution in coal-fired power plants, and in particular to a primary air flow distribution device for a coal mill inlet. Background Art

[0002] With the rise in coal prices, many power plants are giving up high-priced high-quality coal close to the designed coal type and choosing low-cost low-quality coal in order to control power generation costs and increase profits. These low-quality coals are often difficult to grind, which reduces the maximum output of the coal mill, seriously affecting the ability of coal-fired units to carry high loads, and some units even have safety problems.

[0003] Insufficient primary air volume at the coal mill inlet is the main reason for insufficient coal mill output. Figure 1 As shown in the figure, a large coal-fired power plant is generally equipped with six coal mills, which obtain primary air from the primary air duct. Due to the unreasonable layout of the primary air duct, the primary air volume obtained by each coal mill will be quite different, and some coal mills will have serious air shortage problems, resulting in uneven distribution of primary air flow. For coal mills with large primary air volume, the air volume can be appropriately reduced by adjusting the damper. However, for coal mills with serious air shortage, the damper is still in a state of air shortage when it is fully opened, and the primary air volume cannot be increased by conventional adjustment means, resulting in insufficient output of the coal mills with air shortage, which seriously affects the safe and economical operation of the unit. Summary of the invention

[0004] The object of the present invention is to provide a primary air volume distribution device for a coal mill inlet.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A primary air volume distribution device for a coal mill inlet comprises a piping system connected to the coal mill inlet, the piping system comprises a hot primary air duct for conveying hot air, a cold primary air duct for conveying cold air, a first branch pipe, and a second branch pipe, one end of the first branch pipe is connected to the hot primary air duct, and the other end is connected to the coal mill inlet, one end of the second branch pipe is connected to the cold primary air duct, and the other end is connected to the first branch pipe, the device also comprises an air gathering component for increasing the air volume, and a flow guide component for regulating the airflow, the air gathering component is an air gathering pipe, the diameter of one end of the air gathering pipe is larger than the diameter of the other end, and the flow guide component is an arc guide plate.

[0007] Preferably, the wind collecting component includes a first wind collecting duct arranged at the connection between the hot primary air duct and the first branch pipe, one end of the first wind collecting duct is connected to the hot primary air duct, and the other end of the first wind collecting duct is connected to one end of the first branch pipe.

[0008] Preferably, the wind collecting component includes a second wind collecting pipe arranged at the connection between the first branch pipe and the second branch pipe, one end of the second wind collecting pipe is connected to the first branch pipe, and the other end of the first wind collecting pipe is connected to the other end of the second branch pipe.

[0009] Preferably, the diameter of the air collecting pipe changes from one end to the other end in a smooth transition.

[0010] Preferably, the center line of one end of the air collecting duct does not coincide with the center line of the other end.

[0011] Preferably, the pipeline has a curved elbow, and the flow guide component is arranged in the elbow of the pipeline.

[0012] Further preferably, the guide component includes a first guide plate arranged in the elbow of the hot primary air duct.

[0013] Further preferably, the flow guide component includes a second flow guide plate arranged in the elbow of the first branch pipe.

[0014] More preferably, a plurality of flow guide components are provided.

[0015] Further preferably, the curvature of the arc-shaped guide plate of the flow guide component is consistent with the curvature of the elbow of the pipeline.

[0016] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0017] The present invention increases the air volume at the inlet of the coal mill that lacks air by setting a wind gathering component and a flow guide component in the pipeline leading to the coal mill inlet, realizes the uniform distribution of the primary air flow at the inlet of each coal mill, has good applicability, optimizes the flow field in the primary air duct, improves the primary air flow distribution, reduces the resistance in the primary air duct, and reduces the power consumption of the fan. Without changing the existing layout of the hot primary air duct of the coal-fired power plant, the difference in the primary air volume at the inlet of each coal mill is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Attached Figure 1 A schematic diagram of a pipeline system connected to a coal mill inlet in the prior art;

[0019] Attached Figure 2 This is a schematic diagram of a primary air volume distribution device for a coal mill inlet in this embodiment;

[0020] Attached Figure 3 For attachment Figure 1 Enlarged schematic diagram of part A.

[0021] In the above figures: 1. hot primary air duct; 2. cold primary air duct; 3. first branch pipe; 4. second branch pipe; 5. first air collecting duct; 6. second air collecting duct; 7. first guide plate; 8. second guide plate. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. 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] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and 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 cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] like Figure 2 As shown, a primary air volume distribution device for the inlet of a coal mill includes a pipeline system connected to the inlet of the coal mill, a wind gathering component for increasing the air volume, and a flow guide component for regularizing the air flow. The pipeline system is used to transport the primary air generated by the fan to the coal mill. In this embodiment, the pipeline in the pipeline system adopts a square pipe. The pipeline system has a curved elbow, which can help the pipeline system bend around obstacles such as pillars when encountering obstacles.

[0026] The pipeline system includes a hot primary air duct 1 for conveying hot air, a cold primary air duct 2 for conveying cold air, a first branch pipe 3, and a second branch pipe 4. One end of the first branch pipe 3 is connected to the hot primary air duct 1, and the other end is connected to the coal mill inlet (not shown in the figure). One end of the second branch pipe 4 is connected to the cold primary air duct 2, and the other end is connected to the first branch pipe 3. The hot air enters the coal mill through the hot primary air duct 1 and the first branch pipe 3, and the cold air enters the coal mill through the cold primary air duct 2, the second branch pipe 4, and the first branch pipe 3, that is, the hot air and the cold air enter the coal mill inlet after merging in the first branch pipe 3. There are multiple first branch pipes 3, and multiple second branch pipes 4. Each coal mill inlet is connected to a first branch pipe 3, and each first branch pipe 3 is connected to a second branch pipe 4. In this embodiment, there are six coal mill inlets, and six corresponding first branch pipes 3 and second branch pipes 4 are also provided.

[0027] The air gathering component is an air gathering pipe connected to the first branch pipe 3. The diameter of one end of the air gathering pipe is larger than the diameter of the other end, and the diameter of one end changes to the diameter of the other end in a smooth transition. During the change, the surroundings of the air gathering pipe can expand or contract outward at the same time, or only one or more sides can expand or contract outward to adapt to the actual environment, that is, the center lines of the two end faces do not overlap, specifically showing a trumpet shape or a trapezoidal shape. The air gathering pipe includes a first air gathering pipe 5 arranged between the hot primary air pipe 1 and the first branch pipe 3. One end of the first air gathering pipe 5 is connected to the hot primary air pipe 1, and the other end of the first air gathering pipe 5 is connected to one end of the first branch pipe 3. The diameter of one end of the first air gathering pipe is larger, which can increase the area when the hot primary air enters the first branch pipe 3, reduce the resistance entering the first branch pipe 3, and increase the air volume of the hot primary air. The air collecting duct also includes a second air collecting duct 6 arranged between the first branch pipe 3 and the second branch pipe 4. One end of the second air collecting duct 6 is connected to the first branch pipe 3, and the other end of the second air collecting duct 6 is connected to the other end of the second branch pipe 4. The diameter of one end of the second air collecting duct is larger, which can increase the area of ​​the cold primary air entering the first branch pipe 3, reduce the resistance entering the first branch pipe 3, and increase the air volume of the cold primary air. Figure 3 The width of one end of the first air collecting pipe 5 is consistent with the width or height of the hot primary air pipe 1, so that the two opposite sides of the port at one end of the first air collecting pipe 5 coincide with the two opposite sides of the hot primary air pipe 1; the width of one end of the second air collecting pipe 6 is consistent with the width or height of the first branch pipe 3, so that the two opposite sides of the port at one end of the second air collecting pipe 6 coincide with the two opposite sides of the first branch pipe 3.

[0028] The flow guide component is an arc-shaped guide plate arranged in the elbow of the pipeline system. The arc-shaped guide plate is made of high-temperature resistant material. A plurality of arc-shaped guide plates are arranged at each elbow. In the present embodiment, 1-3 arc-shaped guide plates are arranged at each elbow. The arc-shaped guide plate includes a first guide plate 7 arranged in the elbow of the hot primary air duct 1. The curvature of the first guide plate 7 is consistent with the curvature of the elbow where it is located. The regular airflow can reduce the resistance of the primary air in the hot primary air duct 1 and increase the amount of primary air entering the coal mill. The arc-shaped guide plate also includes a second guide plate 8 arranged in the elbow of the first branch pipe 3. The curvature of the second guide plate 8 is consistent with the curvature of the elbow where it is located. The regular airflow can reduce the resistance of the primary air in the first branch pipe 3 and increase the amount of primary air entering the coal mill. Figure 3 shown.

[0029] The wind gathering components and flow guide components are simple in structure and easy to install. In actual use, according to the actual operation of each coal mill, various components are added to the first branch pipe 3 with insufficient primary air. In a preferred embodiment, by adding wind gathering components and flow guide components, the primary air volume at the inlet of the coal mill with the lowest air volume is increased by 23%, which completely solves the problem of air shortage and greatly improves the uniformity of the primary air flow at the inlet of each coal mill.

[0030] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A primary air volume distribution device for a coal mill inlet, comprising a pipeline system connected to the coal mill inlet, the pipeline system comprising a hot primary air duct for conveying hot air, a cold primary air duct for conveying cold air, a first branch pipe, and a second branch pipe, one end of the first branch pipe is connected to the hot primary air duct, and the other end is connected to the coal mill inlet, one end of the second branch pipe is connected to the cold primary air duct, and the other end is connected to the first branch pipe, a plurality of first branch pipes are provided, a plurality of second branch pipes are provided, each coal mill inlet is connected to a first branch pipe, and each first branch pipe is connected to a second branch pipe, characterized in that: The device also includes a wind gathering component for increasing the wind volume and a flow guiding component for regulating the air flow. The wind gathering component is an air gathering pipe, the diameter of one end of the air gathering pipe is larger than the diameter of the other end, the air gathering component comprises a first air gathering pipe arranged at the connection between the hot primary air pipe and the first branch pipe, one end of the first air gathering pipe is connected to the hot primary air pipe, the other end of the first air gathering pipe is connected to one end of the first branch pipe, the width of one end of the first air gathering pipe is consistent with the width or height of the hot primary air pipe, so that the two opposite sides of the port at one end of the first air gathering pipe coincide with the two sides of the pipe body of the hot primary air pipe; the air gathering component comprises a second air gathering pipe arranged at the connection between the first branch pipe and the second branch pipe, one end of the second air gathering pipe is connected to the first branch pipe, the other end of the first air gathering pipe is connected to the other end of the second branch pipe, the width of one end of the second air gathering pipe is consistent with the width or height of the first branch pipe, so that the two opposite sides of the port at one end of the second air gathering pipe coincide with the two sides of the pipe body of the first branch pipe; The flow guide component is an arc-shaped guide plate.

2. The primary air volume distribution device for coal mill inlet according to claim 1, characterized in that: The diameter of the air collecting pipe changes from one end to the other end in a smooth transition.

3. The primary air volume distribution device for coal mill inlet according to claim 1, characterized in that: The center line of one end of the air collecting pipe does not coincide with the center line of the other end.

4. The primary air volume distribution device for coal mill inlet according to claim 1, characterized in that: The pipeline system has a curved elbow, and the flow guide component is arranged in the elbow of the pipeline system.

5. The primary air volume distribution device for coal mill inlet according to claim 4, characterized in that: The flow guide component includes a first flow guide plate arranged in the elbow of the hot primary air duct.

6. The primary air volume distribution device for coal mill inlet according to claim 4, characterized in that: The flow guide component comprises a second flow guide plate arranged in the elbow of the first branch pipe.

7. A primary air volume distribution device for coal mill inlet according to claim 5 or 6, characterized in that: The guide components are provided in plurality.

8. The primary air volume distribution device for coal mill inlet according to claim 4, characterized in that: The curvature of the arc-shaped guide plate of the flow guide component is consistent with the curvature of the elbow of the pipeline.

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