Optimization method for primary air measuring device of thermal power plant

Abstract

The invention provides an optimization method for primary air measuring devices of a thermal power plant. The optimization method comprises the following steps that the multiple primary air measuring devices are movably arranged on the side wall, close to a primary air control valve, of an inlet air duct; the opening degree of the primary air control valve is set to be a first preset opening degree; adopting a grid method to obtain section velocity distribution of the inlet air duct; calculating an air volume calibration value according to the section velocity distribution of the inlet air duct, and drawing a velocity distribution cloud picture according to the section velocity distribution of the inlet air duct; calculating an air volume average value according to each air volume measurement value; adjusting the position of each primary air measuring device by referring to the speed distribution cloud picture until the air volume calibration value is the same as the air volume average value; and the opening degree of the primary air control valve is sequentially increased to a second preset opening degree, so that the positions of the primary air measuring devices at different opening degrees of the primary air control valve are determined. The method has the technical effect that accurate primary air measurement results can be obtained when the primary air control valve is opened to different opening degrees.

Description

Technical Field

[0001] This invention belongs to the field of primary air measurement technology in thermal power plants, and specifically relates to an optimization method for a primary air measurement device in thermal power plants. Background Technology

[0002] Currently, many thermal power plants have short mixing sections in the inlet air ducts of their coal mills, which limits the placement of primary air volume measurement elements. Typically, the primary air measurement elements are placed too close to bends and primary air regulating valves, resulting in a poor flow field at the measurement cross-section and inaccurate air volume measurement. Furthermore, the flow field distribution varies with different valve openings, making accurate primary air volume measurement a challenge.

[0003] Since a crucial factor affecting primary air measurement is the length of the fully developed sections upstream and downstream of the measuring element cross-section, it is generally required that the upstream section be at least 5 times the equivalent diameter and the downstream section at least 2 times the equivalent diameter. However, due to the compact layout of thermal power plants, such large spaces are often unavailable. Therefore, there is an urgent need for a method that can achieve accurate primary air measurement even in compact primary air layouts, especially when the primary air measuring element is close to the primary air control valve. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art, and to provide a new technical solution for an optimization method for a primary air measurement device in a thermal power plant.

[0005] According to a first aspect of the present invention, an optimization method for a primary air measurement device in a thermal power plant is provided, comprising the following steps:

[0006] Step S1: First, multiple primary air measuring devices are movably installed on the side wall of the inlet duct near the primary air regulating valve, and the multiple primary air measuring devices are distributed at intervals along the circumference of the inlet duct; then, the opening degree of the primary air regulating valve is set to a first preset opening degree.

[0007] Step S2: Obtain the cross-sectional velocity distribution of the inlet duct using the grid method;

[0008] Step S3: Calculate the air volume calibration value based on the cross-sectional velocity distribution of the inlet duct, draw a velocity distribution cloud map based on the cross-sectional velocity distribution of the inlet duct, and determine the initial position of multiple primary air measuring devices based on the velocity distribution cloud map;

[0009] Step S4: After the primary air measuring device is fixed in the initial position, observe the displayed value of the primary air volume on the power plant dial and compare it with the primary air volume calibration value of the grid method. If there is a deviation between the two, adjust the position of each primary air measuring device according to the velocity distribution cloud map until the primary air volume displayed on the power plant dial is the same as the primary air volume calibration value measured by the grid method, and record the position of each primary air measuring device.

[0010] Step S5: Increase the opening of the primary air control valve sequentially until the second preset opening, and repeat steps S2 to S4 sequentially to determine the position of each primary air measuring device at different primary air control valve openings.

[0011] Optionally, the optimization method for primary air measurement devices in thermal power plants further includes:

[0012] Step S5: When the primary air regulating damper is opened to different opening degrees, each primary air measuring device is adjusted to the corresponding position, and the actual air volume value of the inlet duct is determined according to the air volume measurement values ​​of each primary air measuring device.

[0013] Optionally, in step S2, the cross-sectional velocity distribution of the inlet duct is obtained using a grid method, including:

[0014] Using the test borehole downstream of the primary air measurement device, the wind speed and temperature in the inlet duct are measured using the grid method to obtain multiple wind speed measurements and multiple temperature measurements. Based on the multiple wind speed measurements and multiple temperature measurements, the cross-sectional velocity distribution of the inlet duct is obtained.

[0015] Optionally, each of the primary air measuring devices moves along the duct wall from the inlet duct toward the center.

[0016] Optionally, the first preset opening is 30%.

[0017] Optionally, the second preset opening degree is 100%.

[0018] Optionally, the opening degree of each subsequent primary air conditioning damper is 10%.

[0019] Optionally, the number of primary air measuring devices is 4-8.

[0020] Optionally, each primary air measuring device is connected to an actuator that drives the primary air measuring device to move along the duct wall from the inlet air duct toward the center.

[0021] Optionally, each of the primary wind measuring devices includes a windward side and a leeward side, and the wind volume measurement value of the wind measuring device is determined based on the wind volume measurement results of the windward side and the leeward side.

[0022] One technical advantage of this invention is that:

[0023] In this embodiment of the application, by determining the position of each primary air measuring device at different primary air regulating valve openings, it is helpful to automatically move each primary air measuring device to the corresponding position when the primary air regulating valve is opened to different openings, thereby helping to obtain accurate primary air measurement results. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating an optimization method for a primary air measurement device in a thermal power plant, according to an embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram showing the relative positional relationship between the primary air regulating door and the primary air measuring device according to an embodiment of the present invention;

[0026] Figure 3 This is a cross-sectional schematic diagram of the primary air measuring device according to an embodiment of the present invention. In the figure: 1, inlet air duct; 2, primary air regulating damper; 3, primary air measuring device; 31, windward side; 32, leeward side; 4, test measuring hole; 5, actuator. Detailed Implementation

[0027] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0028] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0029] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0030] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, 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.

[0031] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" 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 mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0032] According to a first aspect of the invention, see Figures 1 to 3 An optimization method for primary air measurement devices in thermal power plants is provided. When the primary air measurement device 3 is too close to the primary air regulating valve 2, the method automatically selects a suitable position for the primary air measurement device 3 under different opening degrees of the primary air regulating valve 2, thereby improving the accuracy of primary air measurement.

[0033] Specifically, the optimization method for primary air measurement devices in thermal power plants includes the following steps:

[0034] Step S1: First, multiple primary air measuring devices 3 are movably installed on the side wall of the inlet duct 1 near the primary air regulating door 2, and the multiple primary air measuring devices 3 are distributed at intervals along the circumference of the inlet duct 1; then, the opening degree of the primary air regulating door 2 is set to a first preset opening degree.

[0035] Step S2: Use the grid method to obtain the cross-sectional velocity distribution of the inlet duct 1;

[0036] Step S3: Calculate the air volume calibration value based on the velocity distribution of the inlet duct 1 cross-section, and draw a velocity distribution cloud map based on the velocity distribution of the inlet duct 1 cross-section. Determine the initial positions of multiple primary air measuring devices 3 based on the velocity distribution cloud map. The air volume of the entire cross-section is calculated as density × area × velocity. Density can be calculated using temperature and static pressure, while velocity is obtained through dynamic pressure, static pressure, and temperature calculations. The primary air measuring device 3 can obtain dynamic and static pressure. Temperature measuring devices in power plants are generally installed at the coal mill inlet to measure temperature and ensure accuracy.

[0037] Step S4: After the primary air measuring device is fixed in the initial position, observe the displayed value of the primary air volume on the power plant dial and compare it with the primary air volume calibration value obtained by the grid method. If there is a deviation between the two, adjust the position of each primary air measuring device according to the velocity distribution cloud map until the primary air volume displayed on the power plant dial is the same as the primary air volume calibration value measured by the grid method, and record the position of each primary air measuring device. The displayed value of the primary air volume on the power plant dial is the value of the measured value of each primary air measuring device after processing and displayed on the power plant dial.

[0038] Step S5: Increase the opening of the primary air regulating damper 2 sequentially until the second preset opening, and repeat steps S2 to S4 sequentially to determine the position of each primary air measuring device 3 at different openings of the primary air regulating damper 2.

[0039] In this embodiment of the application, by determining the position of each primary air measuring device 3 at different opening degrees of the primary air regulating valve 2, it is helpful to automatically move each primary air measuring device 3 to the corresponding position when the primary air regulating valve 2 is opened to different degrees, thereby helping to obtain accurate primary air measurement results.

[0040] Optionally, the optimization method for primary air measurement devices in thermal power plants further includes:

[0041] Step S6: When the primary air regulating door 2 is opened to different opening degrees, each primary air measuring device 3 is adjusted to the corresponding position, and the actual air volume value of the inlet air duct 1 is determined according to the air volume measurement value of each primary air measuring device 3.

[0042] In the above embodiments, when the primary air regulating damper 2 is opened to different opening degrees, the primary air measuring devices 3 are adjusted to the corresponding positions, which helps to accurately measure the air volume in the inlet duct 1.

[0043] Optionally, in step S2, the cross-sectional velocity distribution of the inlet duct 1 is obtained using a grid method, including:

[0044] Using the test borehole 4 downstream of the primary air measuring device 3, the wind speed and temperature in the inlet air duct 1 are measured using the grid method to obtain multiple wind speed measurements and multiple temperature measurements. Based on the multiple wind speed measurements and multiple temperature measurements, the cross-sectional velocity distribution of the inlet air duct 1 is obtained.

[0045] In the above embodiments, it is helpful to obtain the cross-sectional velocity distribution of the inlet duct 1 simply and quickly.

[0046] Optionally, each of the primary air measuring devices 3 moves along the duct wall from the inlet duct 1 toward the center. This facilitates quick adjustment of the position of the primary air measuring devices 3, and helps to adjust each primary air measuring device 3 to a suitable position to accurately measure the air volume in the inlet duct 1.

[0047] Optionally, the first preset opening is 30%.

[0048] Optionally, the second preset opening degree is 100%.

[0049] Optionally, the opening degree of the primary air conditioning damper 2 is 10%.

[0050] In the above embodiment, it is helpful to quickly adjust the position of the primary air measuring device 3 so that each primary air measuring device 3 can be adjusted to a suitable position to accurately measure the air volume in the inlet air duct 1 at different openings of the primary air regulating valve 2.

[0051] Optionally, the number of primary air measuring devices 3 is 4-8. This helps to accurately measure the air volume within the inlet duct 1.

[0052] Optionally, each primary air measuring device 3 is connected to an actuator 5, which drives the primary air measuring device 3 to move along the duct wall from the inlet duct 1 toward the center. This helps to achieve stable movement of each primary air measuring device 3.

[0053] Optionally, each of the primary air measuring devices 3 includes a windward side 31 and a leeward side 32. The airflow measurement value of the air measuring device is determined based on the airflow measurement results of the windward side 31 and the leeward side 32. This helps the primary air measuring device 3 to accurately obtain the airflow measurement value at the corresponding location.

[0054] It should be noted that, see Figure 1 In the existing technology, because the hot primary air reaches the primary air measuring device 3 after passing through the primary air regulating damper 2, and because the cross-section of the primary air measuring device 3 is too close to the primary air regulating damper 2, the velocity and temperature fields at the cross-section of the primary air measuring device 3 are extremely different, resulting in inaccurate measurement results from the primary air measuring device 3. Furthermore, the disturbance to the primary air caused by the primary air regulating damper 2 varies with its opening degree. When the opening degree of the primary air regulating damper 2 is small, the primary air will be deflected to one side, leading to inaccurate primary air measurement; while when the primary air regulating damper 2 is fully open, the primary air will not be deflected. This results in inconsistent velocity distribution across the primary air measuring cross-section under different opening degrees of the primary air regulating damper 2.

[0055] In this application, the primary air measuring device 3 is movably mounted on the side wall of the inlet duct 1 near the primary air regulating valve 2, allowing the primary air measuring device 3 to move up and down within the duct via the actuator 5. The position of the primary air measuring device 3 within the duct varies depending on the opening degree of the primary air regulating valve 2. Thus, when changes in the primary air regulating valve 2 cause changes in the flow field within the inlet duct 1, multiple primary air measuring devices 3 can be moved to preferred positions, achieving accurate measurement of the airflow within the inlet duct 1.

[0056] In one specific implementation, the operation steps of the mesh method are as follows:

[0057] 1. Select a suitable measurement section. In this application, the section at test hole 4 is the suitable measurement section of inlet duct 1.

[0058] 2. Grid Division. Divide the selected measurement cross-section into a uniform grid. For example, for a rectangular duct, it can be divided into multiple small rectangular regions. The grid size depends on the specific dimensions of the inlet duct 1 and the expected velocity distribution. Generally, larger ducts may require more measurement points to ensure accuracy.

[0059] 3. Measure wind speed. The test generally uses a back-to-back tube for measurement according to the standard. Using the back-to-back tube and thermocouples, the dynamic pressure, static pressure and temperature at each point are measured using the grid method to obtain the velocity at each point; the air volume of the entire cross section = density × area × velocity, where density can be calculated from temperature and static pressure.

[0060] 4. Data Processing. Sum the wind speed values ​​from all measurement points and sum the temperature values, then divide by the total number of measurement points to calculate the cross-sectional velocity distribution of the section.

[0061] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. An optimization method for a primary air measurement device in a thermal power plant, characterized in that, Includes the following steps: Step S1: First, multiple primary air measuring devices are movably installed on the side wall of the inlet duct near the primary air regulating valve, and the multiple primary air measuring devices are distributed at intervals along the circumference of the inlet duct; then, the opening degree of the primary air regulating valve is set to a first preset opening degree. Step S2: Obtain the cross-sectional velocity distribution of the inlet duct using the grid method; Step S3: Calculate the air volume calibration value based on the cross-sectional velocity distribution of the inlet duct, draw a velocity distribution cloud map based on the cross-sectional velocity distribution of the inlet duct, and determine the initial position of multiple primary air measuring devices based on the velocity distribution cloud map; Step S4: After the primary air measuring device is fixed in the initial position, observe the displayed value of the primary air volume on the power plant dial and compare it with the primary air volume calibration value of the grid method. If there is a deviation between the two, adjust the position of each primary air measuring device according to the velocity distribution cloud map until the primary air volume displayed on the power plant dial is the same as the primary air volume calibration value measured by the grid method, and record the position of each primary air measuring device. Step S5: Increase the opening of the primary air control valve sequentially until the second preset opening, and repeat steps S2 to S4 sequentially to determine the position of each primary air measuring device at different primary air control valve openings.

2. The optimization method for a primary air measurement device in a thermal power plant according to claim 1, characterized in that, Also includes: Step S6: When the primary air regulating damper is opened to different opening degrees, each primary air measuring device is adjusted to the corresponding position, and the actual air volume value of the inlet duct is determined according to the air volume measurement value of each primary air measuring device.

3. The optimization method for a primary air measurement device in a thermal power plant according to claim 2, characterized in that, Step S2 includes: Using the test borehole downstream of the primary air measurement device, the wind speed and temperature in the inlet duct are measured using the grid method to obtain multiple wind speed measurements and multiple temperature measurements. Based on the multiple wind speed measurements and multiple temperature measurements, the cross-sectional velocity distribution of the inlet duct is obtained.

4. The optimization method for a primary air measurement device in a thermal power plant according to claim 3, characterized in that, Each of the aforementioned primary air measuring devices moves along the duct wall from the inlet air duct toward the center.

5. The optimization method for a primary air measurement device in a thermal power plant according to claim 4, characterized in that, The first preset opening is 30%.

6. The optimization method for a primary air measurement device in a thermal power plant according to claim 5, characterized in that, The second preset opening degree is 100%.

7. The optimization method for a primary air measurement device in a thermal power plant according to claim 6, characterized in that, The opening degree of each subsequent air conditioning damper increases by 10%.

8. The optimization method for a primary air measurement device in a thermal power plant according to claim 7, characterized in that, The number of primary air measuring devices is 4-8.

9. The optimization method for a primary air measurement device in a thermal power plant according to claim 8, characterized in that, Each primary air measurement device is connected to an actuator, which drives the primary air measurement device to move along the duct wall from the inlet air duct toward the center.

10. The optimization method for a primary air measurement device in a thermal power plant according to claim 9, characterized in that, Each of the primary wind measuring devices includes a windward side and a leeward side, and the wind volume measurement value of the wind measuring device is determined based on the wind volume measurement results of the windward side and the leeward side.

Images