A pulverized coal flow regulating valve for a boiler air-powder pipeline and a control method thereof

Abstract

This invention provides a pulverized coal flow regulating valve and its control method for a boiler air-coal pipeline. A pulverized coal flow regulating valve is installed between a coal mill and several pulverized coal pipelines connected to the coal mill. The pulverized coal flow regulating valve includes: a regulating valve body, a permanent magnet servo actuator and a spur gear reducer mounted on the outer shell of the regulating valve body, a double-comb-tooth valve plate rotatably connected inside the regulating valve body, and bearing seats mounted on the regulating valve body and located on both sides of the double-comb-tooth valve plate. The permanent magnet servo actuator drives the spur gear reducer, and the output shaft of the spur gear reducer drives the double-comb-tooth valve plate to rotate axially along the radial direction of the regulating valve body inside the regulating valve body. The double-comb-tooth valve plate consists of a central blocking plate and a comb-tooth plate integrally formed with the central blocking plate. The advantage of this invention is that the pulverized coal flow regulating valve improves the balance of pulverized coal distribution in each conveying pipeline of the pulverizing system and the uniformity of air-coal distribution in the branch pipes, thus creating good combustion conditions in the furnace.

Description

Technical Field

[0001] The present invention belongs to the technical field of pulverizing systems, and more specifically, relates to a pulverized coal flow regulating valve of a boiler air-pulverized coal pipeline and a control method thereof. Background Art

[0002] The coal mill and several coal powder pipelines connected to it constitute the pulverizing system, which is responsible for grinding the raw coal into coal powder of qualified fineness and transporting it to the boiler for combustion. The pulverizing system has uneven distribution of coal powder in each transportation pipeline, large deviation of the amount of powder in each branch pipe, and large deviation of the air-coal ratio, which results in insufficient mixing of air and powder in the later stage, unsatisfactory combustion conditions, slow load response, high combustibles in the furnace, uneven air and powder in each branch pipe, and rope winding. If the stratified air and coal powder enter the burner, it will lead to unstable flame, uneven combustion, increased unburned carbon, slagging, scouring of furnace wall, and imbalance of CO and O2.

[0003] Improving the balance of pulverized coal distribution in each conveying pipeline of the pulverizing system and the uniformity of air and pulverized coal in the branch pipes will form good combustion conditions in the furnace and is the basis for other combustion adjustment and control; at the same time, good pulverized coal balance helps to improve the combustion efficiency of the boiler and the safety of its operation. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a coal powder flow regulating valve for a boiler air-powder pipeline and a control method thereof, which are used to improve the balance of coal powder distribution in various conveying pipelines of the pulverizing system and the uniformity of air and powder in the branch pipes, so as to overcome the shortcomings of the above-mentioned prior art.

[0005] The pulverized coal flow regulating valve of the boiler air-powder pipeline provided by the present invention comprises: a coal mill and a plurality of pulverized coal pipelines connected to the coal mill, and the improvement made is that a pulverized coal flow regulating valve is arranged between the coal mill and the plurality of pulverized coal pipelines connected to the coal mill, and the pulverized coal flow regulating valve comprises: a regulating valve body, a permanent magnet servo actuator and a spur gear reducer installed on the outer shell of the regulating valve body, a double-comb-tooth valve plate rotatably connected to the inside of the regulating valve body, and a bearing seat installed on the regulating valve body and located on both sides of the double-comb-tooth valve plate, wherein the The regulating valve body includes: an outer shell and a sealing shell attached to the inner wall of the outer shell, the permanent magnet servo actuator drives the spur reducer, the output shaft of the spur reducer drives the double-comb-tooth valve plate to rotate axially along the radial direction of the regulating valve body inside the regulating valve body, and the two ends of the output shaft are rotatably connected to the two bearing seats. The double-comb-tooth valve plate is composed of a central blocking plate and a comb plate integrally formed with the central blocking plate, the central blocking plate is located at the center of the comb plate, and the gaps between the comb teeth of the comb plate are used to pass coal powder.

[0006] Preferably, the regulating valve body is cylindrical, and the double-comb-tooth valve plate is located in the middle of the regulating valve body and divides the regulating valve body into two cavities.

[0007] Preferably, the outer contour of the comb plate is consistent with the shape of the cross section in the middle of the regulating valve body.

[0008] Preferably, a spur reducer mounting seat is provided on the outer wall of the outer shell, the spur reducer is mounted on the spur reducer mounting seat, the permanent magnet servo actuator is mounted on the spur reducer, and the output shaft of the permanent magnet servo actuator drives the output shaft of the spur reducer.

[0009] Preferably, the inner diameter of the regulating valve body is larger than the inner diameter of the pulverized coal pipeline.

[0010] Preferably, the comb plate is composed of two groups of symmetrically arranged comb teeth, each group of comb teeth is arranged in parallel, and a through hole for the output shaft to pass through is radially arranged inside the comb plate and the central blocking plate.

[0011] Another object of the present invention is to provide a method for controlling the flow state of pulverized coal of a pulverized coal flow regulating valve of a boiler air-pulverized coal pipeline, which specifically comprises the following steps:

[0012] Step S1: installing a pulverized coal flow regulating valve between the coal mill and a plurality of pulverized coal pipelines connected to the coal mill, and controlling the flow state of the pulverized coal by the pulverized coal flow regulating valve;

[0013] Step S2: using a double-comb-tooth valve plate inside the pulverized coal flow regulating valve to separate the regulating valve body into a front chamber and a rear chamber;

[0014] Step S3: using a pulverized coal flow regulating valve having an inner diameter larger than that of the pulverized coal pipeline, the pulverized coal flow passing through the pulverized coal pipeline is blocked and rebounded under the damping effect of the central blocking plate of the double-comb-tooth valve plate;

[0015] Step S4: Under the joint action of the coal powder flow rebounded by the central blocking plate and the newly incoming coal powder flow, an area with a relatively large wind-powder concentration is formed in the front chamber; when the coal powder concentration of the coal powder pipeline is higher than that of other coal powder pipelines, the permanent magnet servo actuator controls the double-comb-tooth valve plate to reduce the opening angle, and the coal powder concentration in the front chamber is further increased, resulting in an increase in the resistance at the inlet of the coal powder pipeline, reducing the entry of coal powder, thereby reducing the powder concentration of the coal powder pipeline; on the contrary, when the coal powder concentration of the coal powder pipeline is lower than that of other coal powder pipelines, the magnetic servo actuator controls the double-comb-tooth valve plate to increase the opening angle, and the coal powder concentration in the front chamber is reduced, resulting in a decrease in the resistance at the inlet of the coal powder pipeline, increasing the entry of coal powder, thereby increasing the powder concentration of the coal powder pipeline.

[0016] Preferably, in step S2, the bidirectionally adjustable double-comb valve plate is also used to break up the common rope-like flow pattern of coal powder in the coal powder pipeline, so that the coal powder in the coal powder pipeline is more evenly distributed, reducing the strong wear of coal powder on certain parts of the coal powder pipeline, extending the service life of the coal powder pipeline, and solving the flow patterns of biased flow, rope flow, surging flow, and intermittent flow in the primary air duct.

[0017] The advantages and positive effects of the present invention are:

[0018] 1. The present invention improves the balance of coal powder distribution in each conveying pipeline of the pulverizing system and the uniformity of air and powder in the branch pipe through the coal powder flow regulating valve, which will form good combustion conditions in the furnace and is the basis for other combustion adjustment and control; at the same time, the good balance of coal powder helps to improve the combustion efficiency of the boiler and the safety of operation.

[0019] 2. The double-comb-tooth valve plate of the present invention adopts a double-comb-tooth structure, which can solve the problems of primary wind speed deviation and coal powder distribution deviation in each coal powder pipeline. Its effect is better than the existing coal powder pipeline on the market with a coal powder disperser and a corresponding control valve device.

[0020] 3. The present invention adjusts and controls the flow state of air and powder in the coal powder pipeline through the coal powder flow regulating valve, thereby solving the imbalance problem between burners on each layer, optimizing the distribution of coal powder from the pulverizer to the burner, accurately balancing the flow of coal powder and air, improving the coal powder distribution ratio, and improving boiler performance.

[0021] 4. The pulverized coal flow regulating valve of the present invention is specially designed for multi-outlet pulverized coal flow balance, optimizes the pulverized coal distribution from the coal mill to the burner, accurately adjusts the air-powder flow state, and has a unique micro-disturbance (double-comb valve plate) design that can prevent blockage and jamming. It is safe and reliable and helps to reduce excess fly ash carbon content and nitrogen oxides to improve combustion. It does not increase resistance to the pipeline when no adjustment is required. It can be operated manually or in a closed loop to improve combustion efficiency, make the boiler burn more stably, reduce coal consumption, and increase the potential for pulverized coal output from the coal mill.

[0022] 5. The pulverized coal flow regulating valve of the present invention can adjust the flow state of air and pulverized coal, further reduce the wear of the pulverized coal pipeline and the core plate, improve combustion, reduce the phenomenon of excessive flame length, eliminate the separation of the flame and the burner, and use new wear-resistant materials with high strength and wear resistance, which can be used for more than five years. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] By referring to the following description in conjunction with the accompanying drawings, and with a more comprehensive understanding of the present invention, other objects and results of the present invention will become more apparent and easy to understand. In the accompanying drawings:

[0024] Figure 1 It is a front view of the overall structure according to an embodiment of the present invention.

[0025] Figure 2 It is a side view of the overall structure according to an embodiment of the present invention.

[0026] Figure 3 FIG. 2 is a schematic diagram of a local structure according to an embodiment of the present invention.

[0027] Figure 4 Schematic diagram of the double-comb valve plate structure according to an embodiment of the present invention.

[0028] The reference numerals include: regulating valve body 1 , outer shell 101 , sealing shell 102 , permanent magnet servo actuator 2 , spur gear reducer 3 , double comb-tooth valve plate 4 , central blocking plate 401 , comb-tooth plate 402 , bearing seat 5 . DETAILED DESCRIPTION

[0029] In the following description, for the purpose of illustration, in order to provide a comprehensive understanding of one or more embodiments, many specific details are set forth. However, it is apparent that these embodiments may also be implemented without these specific details. In other examples, for ease of describing one or more embodiments, known structures and devices are shown in the form of block diagrams.

[0030] Example 1

[0031] See also Figure 1-4 The pulverized coal flow regulating valve of the boiler air-powder pipeline provided by the present invention comprises: a coal mill and a plurality of pulverized coal pipelines connected to the coal mill, wherein a pulverized coal flow regulating valve is arranged between the coal mill and the plurality of pulverized coal pipelines connected to the coal mill, and the pulverized coal flow regulating valve comprises: a regulating valve body 1, a permanent magnet servo actuator 2 and a spur gear reducer 3 installed on the outer shell of the regulating valve body 1, a double-comb-tooth valve plate 4 rotatably connected to the inside of the regulating valve body 1, and a bearing seat 5 installed on the regulating valve body 1 and located on both sides of the double-comb-tooth valve plate 4, wherein the regulating valve body 1 comprises: an outer shell 101 and a bearing seat 5 attached to the inner wall of the outer shell 101. The sealed shell 102 on the outer shell 101 is provided with flanges at both ends, the permanent magnet servo actuator 2 drives the spur reducer 3, the output shaft of the spur reducer 3 drives the double-comb-tooth valve plate 4 to rotate radially to axially inside the regulating valve body 1, and the two ends of the output shaft are rotatably connected to the bearings inside the two bearing seats 5, the double-comb-tooth valve plate 4 is composed of a central plugging plate 401 and a comb plate 402 integrally formed with the central plugging plate 401, the central plugging plate 401 is located at the center of the comb plate 402, and the gaps between the comb teeth of the comb plate 402 are used to pass coal powder.

[0032] The regulating valve body 1 in this embodiment is cylindrical, the double-comb valve plate 4 is located in the middle of the regulating valve body 1 and divides the regulating valve body 1 into two cavities (front cavity and rear cavity), and the inner diameter of the regulating valve body 1 is larger than the inner diameter of the coal powder pipeline.

[0033] The outer contour of the comb plate 402 in this embodiment is consistent with the shape of the cross section in the middle of the regulating valve body 1. The comb plate 402 is composed of two groups of symmetrically arranged comb teeth, each group of comb teeth is arranged in parallel, and a through hole for the output shaft to pass through is radially arranged inside the comb plate 402 and the central blocking plate 401.

[0034] In this embodiment, a spur gear reducer mounting seat is provided on the outer wall of the outer shell 101 of the regulating valve body 1, the spur gear reducer 3 is mounted on the spur gear reducer mounting seat, the permanent magnet servo actuator 2 is mounted on the spur gear reducer 3, and the output shaft of the permanent magnet servo actuator 3 drives the output shaft of the spur gear reducer 2.

[0035] Working principle: The double-comb-tooth valve plate 4 inside the regulating valve body 1 is controlled by driving the spur-tooth reducer 3 through the permanent magnet servo actuator 2, so that the double-comb-tooth valve plate 4 rotates axially along the radial direction of the regulating valve body 1 inside the regulating valve body 1. Since the inner diameter of the pulverized coal flow regulating valve in this application is larger than the inner diameter of the pulverized coal pipeline, the pulverized coal flow passing through the pulverized coal pipeline is blocked and rebounded by the damping action of the central plugging plate of the double-comb-tooth valve plate 4; under the joint action of the pulverized coal flow rebounded by the central plugging plate and the newly incoming pulverized coal flow, an area with a relatively large air-powder concentration is formed in the front chamber; when When the coal powder concentration of this coal powder pipeline is higher than that of other coal powder pipelines, the permanent magnet servo actuator controls the double-comb-tooth valve plate to increase the opening angle, and the coal powder concentration in the front chamber is further increased, resulting in an increase in the resistance at the inlet of the coal powder pipeline, reducing the entry of coal powder, thereby reducing the powder concentration of the coal powder pipeline; on the contrary, when the coal powder concentration of this coal powder pipeline is lower than that of other coal powder pipelines, the magnetic servo actuator controls the double-comb-tooth valve plate to increase the opening angle, and the coal powder concentration in the front chamber is reduced, resulting in a decrease in the resistance at the inlet of the coal powder pipeline, increasing the entry of coal powder, thereby increasing the powder concentration of the coal powder pipeline.

[0036] Example 2

[0037] This embodiment provides a method for controlling the flow state of pulverized coal of a pulverized coal flow regulating valve of a boiler air-pulverized coal pipeline, which specifically includes the following steps:

[0038] Step S1: installing a pulverized coal flow regulating valve 1 between the coal mill and a plurality of pulverized coal pipelines connected to the coal mill, and controlling the flow state of the pulverized coal by the pulverized coal flow regulating valve 1;

[0039] Step S2: using the double comb-tooth valve plate 4 inside the pulverized coal flow regulating valve 1 to separate the regulating valve body 1 into a front chamber and a rear chamber;

[0040] Step S3: using the pulverized coal flow regulating valve 1 whose inner diameter is larger than the inner diameter of the pulverized coal pipeline, the pulverized coal flow passing through the pulverized coal pipeline is blocked and rebounded under the damping effect of the central blocking plate 401 of the double-comb valve plate 4;

[0041] Step S4: Under the joint action of the coal powder flow rebounded by the central blocking plate 401 and the newly incoming coal powder flow, an area with a relatively large wind-powder concentration is formed in the front chamber; when the coal powder concentration of the coal powder pipeline is higher than that of other coal powder pipelines, the permanent magnet servo actuator 2 controls the double-comb-tooth valve plate 4 to reduce the opening angle, and the coal powder concentration in the front chamber is further increased, resulting in an increase in the resistance at the inlet of the coal powder pipeline, reducing the entry of coal powder, thereby reducing the powder concentration of the coal powder pipeline; on the contrary, when the coal powder concentration of the coal powder pipeline is lower than that of other coal powder pipelines, the magnetic servo actuator 2 controls the double-comb-tooth valve plate 4 to increase the opening angle, and the coal powder concentration in the front chamber is reduced, resulting in a decrease in the resistance at the inlet of the coal powder pipeline, increasing the entry of coal powder, thereby increasing the powder concentration of the coal powder pipeline.

[0042] In step S2 of the present embodiment, the bidirectionally adjustable double-comb valve plate 4 is also used to break up the common rope-like flow pattern of coal powder in the coal powder pipeline, so that the coal powder in the coal powder pipeline is more evenly distributed, reducing the strong wear of coal powder on certain parts of the coal powder pipeline, extending the service life of the coal powder pipeline, and solving the flow patterns of biased flow, rope-like flow, surging flow, and intermittent flow in the primary air duct.

[0043] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for controlling the flow state of pulverized coal of a pulverized coal flow regulating valve of a boiler air-pulverized coal pipeline, characterized in that: The following steps are involved: Step S1: installing a pulverized coal flow regulating valve between the coal mill and a plurality of pulverized coal pipelines connected to the coal mill, and controlling the flow state of the pulverized coal by the pulverized coal flow regulating valve; Step S2: using a double-comb-tooth valve plate inside the pulverized coal flow regulating valve to separate the regulating valve body into a front chamber and a rear chamber; Step S3: using a pulverized coal flow regulating valve having an inner diameter larger than that of the pulverized coal pipeline, the pulverized coal flow passing through the pulverized coal pipeline is blocked and rebounded under the damping effect of the central blocking plate of the double-comb valve plate; Step S4: Under the combined effect of the coal powder flow rebounded by the central blocking plate and the newly incoming coal powder flow, a region with a relatively large air-powder concentration is formed in the front chamber; when the coal powder concentration of the coal powder pipeline is higher than that of other coal powder pipelines, the permanent magnetic servo actuator controls the double-comb-tooth valve plate to reduce the opening angle, and the coal powder concentration in the front chamber is further increased, resulting in an increase in the resistance at the inlet of the coal powder pipeline, reducing the entry of coal powder, thereby reducing the powder concentration of the coal powder pipeline; on the contrary, when the coal powder concentration of the coal powder pipeline is lower than that of other coal powder pipelines, the magnetic servo actuator controls the double-comb-tooth valve plate to increase the opening angle, and the coal powder concentration in the front chamber is reduced, resulting in a reduction in the resistance at the inlet of the coal powder pipeline, increasing the entry of coal powder, thereby increasing the powder concentration of the coal powder pipeline; The pulverized coal flow regulating valve comprises: a regulating valve body, a permanent magnet servo actuator and a spur gear reducer installed on the outer shell of the regulating valve body, a double-comb-tooth valve plate rotatably connected to the inside of the regulating valve body, and a bearing seat installed on the regulating valve body and located on both sides of the double-comb-tooth valve plate, wherein the regulating valve body comprises: an outer shell and a sealing shell attached to the inner wall of the outer shell, the permanent magnet servo actuator drives the spur gear reducer, the output shaft of the spur gear reducer drives the double-comb-tooth valve plate to rotate axially along the radial direction of the regulating valve body inside the regulating valve body, and the two ends of the output shaft are rotatably connected to the two bearing seats, and the double-comb-tooth valve plate consists of a central plugging plate and a comb plate integrally formed with the central plugging plate, the central plugging plate is located at the center of the comb plate, and the gaps between the comb teeth of the comb plate are used to pass the pulverized coal; A spur reducer mounting seat is provided on the outer wall of the outer shell, the spur reducer is mounted on the spur reducer mounting seat, the permanent magnet servo actuator is mounted on the spur reducer, and the output shaft of the permanent magnet servo actuator drives the output shaft of the spur reducer; The inner diameter of the regulating valve body is larger than the inner diameter of the pulverized coal pipeline.

2. The method for controlling the powder flow state of a pulverized coal flow regulating valve of a boiler air-powder pipeline according to claim 1, characterized in that: The regulating valve body is cylindrical, and the double-comb-tooth valve plate is located in the middle of the regulating valve body and divides the regulating valve body into two cavities.

3. The method for controlling the flow state of pulverized coal of a pulverized coal flow regulating valve of a boiler air-pulverized coal pipeline according to claim 1, characterized in that: The outer contour of the comb plate is consistent with the shape of the cross section in the middle of the regulating valve body.

4. The method for controlling the flow state of pulverized coal of a pulverized coal flow regulating valve of a boiler air-pulverized coal pipeline according to claim 1, characterized in that: The comb plate is composed of two groups of symmetrically arranged comb teeth, each group of comb teeth is arranged in parallel, and a through hole for the output shaft to pass through is radially arranged inside the comb plate and the central blocking plate.

5. The method for controlling the flow state of pulverized coal of a pulverized coal flow regulating valve of a boiler air-pulverized coal pipeline according to claim 1, characterized in that: In step S2, the bidirectionally adjustable double-comb valve plate is also used to break up the common rope-like flow pattern of coal powder in the coal powder pipeline, so that the coal powder in the coal powder pipeline is more evenly distributed, reducing the strong wear of coal powder on certain parts of the coal powder pipeline, extending the service life of the coal powder pipeline, and solving the flow patterns of biased flow, rope flow, surging flow, and intermittent flow in the primary air duct.

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