Flue gas flow measuring method and measuring device

Abstract

The invention relates to a flue gas flow measuring method and device, the flue gas flow measuring method and device are used for measuring the flow of gas circulating in a flue, the flue is provided with a plurality of CEMS comparison holes, and each CEMS comparison hole is provided with a flange plate, and the flue gas flow measuring method comprises the following steps: dividing the flue into a plurality of measuring areas by using a partition part; at least one measuring position is arranged in each measuring area; the flow of gas flowing through the flue is measured and calculated through the measuring position; the device has the advantage of improving the accuracy of flue gas measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of smoke flow monitoring, and in particular to a smoke flow measurement method and a measurement device. Background Art

[0002] For large thermal power units, in order to achieve refined control of the gas flow in the pipeline, it is usually necessary to monitor the gas flow in the pipeline.

[0003] Based on the requirement of four flow rate CMS points in front and two in the back, the flow rate measurement point is four times the diameter away from the upstream diameter change or inflection point, and twice the diameter away from the downstream diameter change or elbow. However, due to the complexity of power plant pipelines, it is difficult to meet the requirements in the setting of sampling points. At the same time, some pipelines are close to elbows and other locations, and the flow field distribution is complex, making it difficult to accurately measure the flow rate of the gas in the pipeline.

[0004] Therefore, it is urgent for those skilled in the art to provide a flue gas flow measurement method and a flue gas flow measurement device to improve the accuracy of flue gas measurement. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defects in the prior art, thereby providing a measuring device and a measuring method suitable for measuring the flue gas flow in a pipeline.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A flue gas flow measurement method is used to measure the gas flow flowing through a flue, wherein the flue is provided with a plurality of CEMS comparison holes, each of which is provided with a flange, and comprises the following steps:

[0008] Using a partitioning portion to divide a plurality of measurement areas in the flue;

[0009] At least one measuring position is provided in each of the measuring areas;

[0010] The gas flow rate flowing through the flue is measured and calculated through the measuring position.

[0011] Preferably, the step of dividing the flue into a plurality of measurement zones using a partitioning unit specifically comprises the following steps:

[0012] Selecting the pipe section of the flue provided with the flange as the measuring pipe section;

[0013] Design the parameters and installation position of the partition part according to the size of the measuring pipe section and the installation position of the flange on the measuring pipe section;

[0014] According to the parameters and the installation position, the partition part is installed in the measuring pipe section so that a plurality of measuring areas are evenly distributed along the axial direction of each flange.

[0015] Preferably, at least one measuring position is provided in each measuring area, and specifically comprises the following steps:

[0016] Setting the measuring position on the same cross section of all the measuring areas;

[0017] The measuring position is arranged in the central area of ​​the measuring region.

[0018] Preferably, the measuring and calculating the gas flow rate of the flue through the measuring position includes:

[0019] Calculate the estimated flow rate for each of the measurement zones

[0020]

[0021] Where: K is the flow meter coefficient; ΔP is the differential pressure value measured at the measuring position, Pa; ρ is the density of wet flue gas under actual working conditions, kg / m 3 ;

[0022] Calculate the partition flow Q for each measurement area sn ,

[0023]

[0024]

[0025]

[0026] Where: F is the cross-sectional area of ​​the measurement area; K V is the velocity field coefficient; is the average flow rate of wet flue gas in the cross section, m / s; Q s is the volume flow rate of wet flue gas under actual working conditions, m3 / h; t s is the flue gas temperature, °C; B a is atmospheric pressure, Pa; P S is the flue gas static pressure, Pa; X SW is the humidity content of flue gas; n is the partition number;

[0027] For each partition flow Q sn Sum them to calculate the total flue gas flow Q.

[0028] Preferably, the step of measuring and calculating the gas flow rate of the flue through the measuring position further includes the following steps:

[0029] Before testing, the velocity field coefficient K V Determination;

[0030] During the detection process, the velocity field coefficient K is measured at a preset time interval. V Perform calibration.

[0031] A flue gas flow measurement device based on the above flue gas flow measurement method is used to measure the gas flow flowing through a flue, wherein a plurality of CEMS comparison holes are provided on the flue, and each of the CEMS comparison holes is provided with a flange, comprising:

[0032] A partitioning portion, used for being installed in the flue to divide the flue into a plurality of measurement areas;

[0033] The measuring part comprises a measuring component and a calculating component. The measuring component is used to extend into a measuring position arranged in the measuring area; the calculating component is used to calculate the gas flow rate flowing through the flue according to the data measured by the measuring component.

[0034] Preferably, the partition portion includes a first plate and a second plate cross-distributed at a preset angle;

[0035] The first plates are distributed along the axial direction of the flange, and the second plates are arranged between two adjacent flanges, so that a plurality of measuring areas are evenly distributed along the axial direction of each flange.

[0036] Preferably, the first plate and the second plate are detachably connected;

[0037] and / or,

[0038] The second plate is clamped onto the first plate along the flue gas flow upward and is perpendicular to the first plate.

[0039] Preferably, the measuring position is arranged in a central area of ​​the measuring region.

[0040] Preferably, the measuring part and the flange are arranged in one-to-one correspondence;

[0041] The measuring part is fixed on the flange corresponding to it, and the measuring assembly includes a plurality of pitot tubes arranged at the measuring positions corresponding to the axial distribution of the flange;

[0042] The Pitot tube extends axially along the flange to the corresponding measuring position;

[0043] The measuring part also includes a supporting fixture, which is disposed around the outside of the Pitot tube and is fixedly connected to the Pitot tube and the flange.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The flue gas flow measurement method provided in the above technical solution divides a plurality of measurement areas in the flue through a partition part, so that the multiple measurement areas are separated by a physical structure (partition part) to avoid the flow of fluids between the measurement areas from affecting each other, which can improve the accuracy of flow velocity measurement in different measurement areas. Furthermore, a measurement position is set in each measurement area, and the gas flow in the flue is measured and calculated through the measurement position, which can effectively improve the accuracy of gas flow measurement. Correspondingly, a flue gas flow measurement device of the above scheme can effectively improve the accuracy of flow velocity measurement in different measurement areas through the coordinated use of the partition part and the measurement component, and further improve the accuracy of gas flow measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1 A schematic diagram of the steps of one embodiment of the method of the present invention.

[0048] Figure 2 for Figure 1 A schematic diagram of one example of step S1 and step S2.

[0049] Figure 3 for Figure 1 A schematic diagram of one example of the S3 step.

[0050] Figure 4 This is a schematic diagram of the position of the measuring device provided by the present invention in the flue.

[0051] Figure 5 for Figure 4 Schematic diagram of the structure of the first plate.

[0052] Figure 6 for Figure 4 Schematic diagram of the structure of the second plate.

[0053] Figure 7 for Figure 4 Schematic diagram from another perspective.

[0054] Figure 8 for Figure 7 Schematic diagram of the cut along section AA.

[0055] Fig. 9 for Figure 8A magnified schematic diagram of position B in the middle.

[0056] Fig.10 for Figure 8 Installation diagram of the measuring part and flange.

[0057] Fig.11 for Fig.10 Schematic diagram from another perspective.

[0058] Description of reference numerals:

[0059] 100, flue; 1001, measuring pipe section; 200, flange; 1, partition part; 11, first plate; 110, through hole; 111, first slot; 12, second plate; 121, second slot; 2, measuring area; 20, measuring position; 21, cross section; 3, measuring part; 31, measuring component; 311, Pitot tube; 32, calculation component; 33, supporting firmware. DETAILED DESCRIPTION

[0060] 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.

[0061] 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.

[0062] 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.

[0063] See also Figures 1 to 11This embodiment provides a flue gas flow measurement method for measuring the gas flow flowing through a flue 100. The flue 100 is provided with a plurality of CEMS comparison holes, each of which is provided with a flange 200. It is worth noting that in this embodiment, the flue 100 is rectangular, but in actual applications, the shape and size of the flue 100 are not limited, and the flue 100 can also be set to be circular.

[0064] Specifically, the smoke flow measurement method provided in this embodiment includes the following steps:

[0065] S1: A plurality of measuring areas 2 are divided in the flue 100 by using the partitioning part 1.

[0066] S2: In each measuring area 2, at least one measuring position 20 is provided.

[0067] S3: The gas flow rate flowing through the flue 100 is measured and calculated by the measuring position 20 .

[0068] A plurality of measurement areas 2 are divided into the flue 100 by the partition part 1, so that the plurality of measurement areas 2 are separated by a physical structure (partition part 1), so as to avoid mutual influence of the flow of fluids between the measurement areas 2, thereby improving the accuracy of flow velocity measurement in different measurement areas 2. Furthermore, a measurement position 20 is set in each measurement area 2, and the gas flow in the flue 100 is measured and calculated by the measurement position 20, thereby effectively improving the accuracy of gas flow measurement.

[0069] Specifically, step S1 includes:

[0070] S1.1: Select the pipe section of the flue 100 provided with the flange 200 as the measuring pipe section 1001.

[0071] S1.2: According to the size of the measuring pipe section 1001 and the installation position of the flange 200 on the measuring pipe section 1001, design the parameters and installation position of the partition 1;

[0072] S1.3: According to the parameters and the installation position, the partition part 1 is installed in the measuring pipe section 1001 so that a plurality of measuring areas 2 are evenly distributed along the axial direction of each flange 200 .

[0073] This setting is conducive to setting the parameter design and installation position of the partition part 1 based on the selected measuring pipe section 1001, ensuring the partitioning effect of the partition part 1 on the flue 100 and the installation effect of the partition part 1 itself. In addition, it can be known that there are several measuring areas 2 distributed along the axial direction of each flange 200, and the entire measuring device can also be installed corresponding to the flange 200, which is convenient for the positioning and installation of the entire measuring device, and further increases the accuracy of the measurement.

[0074] Furthermore, in this embodiment, step S2 specifically includes the following steps:

[0075] S2.1: Setting a measuring position 20 on the same cross section 21 of all measuring zones 2;

[0076] S2.2: Set the measuring position 20 in the central area of ​​the measuring area 2. It is worth noting that, taking one of the measuring areas 2 as an example, the "central area" referred to here is an area with the center point of the measuring area 2 as the center of the circle and a diameter within 0.25% of the width or length of the measuring area 2. Specifically, it can be set according to the shape and area of ​​the measuring area 2, the number and diameter of the Pitot tubes 311, and the shape and size of the flue 100. It can be known that although the central area in this embodiment is a circle, it is not limited to a circle.

[0077] In this embodiment, step S3 specifically includes:

[0078] S3.0: Before testing, the velocity field coefficient K V Specifically, the velocity field coefficient K V The measurement method can refer to the corresponding measurement method of HJ75. Considering the limited space, the speed of different points can be measured at the center (center of the circle) of the reserved hole (the hole for installing the measuring part 3) set 1m away from the flange 200 for evaluation.

[0079] S3.1: Calculate the estimated flow rate for each measurement zone 2 The specific calculation is done using the following formula:

[0080]

[0081] Where: K is the flow meter coefficient; ΔP is the differential pressure value measured at the measuring position 20, Pa; ρ is the density of wet flue gas under actual working conditions, kg / m 3 Among them, K can be obtained based on the selected flow meter, and ρ can be obtained based on the system detection instrument.

[0082] S3.2: Calculate the subarea flow Q for each measurement zone 2 sn . Partition flow Q sn Calculate using the following formula:

[0083]

[0084]

[0085]

[0086] Where: F is the cross-sectional area of ​​measurement area 2; K V is the velocity field coefficient; is the average flow rate of wet flue gas in the cross section, m / s; Q s is the volume flow rate of wet flue gas under actual working conditions, m3 / h; t s is the flue gas temperature, °C; B a is atmospheric pressure, Pa; P S is the flue gas static pressure gauge pressure, Pa; X SW is the humidity content of flue gas; n is the partition number;

[0087] S3.3: For each partition flow Q sn Sum them up to calculate the total flue gas flow Q. That is:

[0088] Q=Q s1 +Q s2 +Q s3 +Q s4 ……+Q sn ;

[0089] S3.4: During the detection process, the velocity field coefficient K is measured at preset intervals. V Specifically, the preset interval can be set to one month.

[0090] See also Figures 4 to 11 Based on the above-mentioned flue gas flow method, this embodiment provides a flue gas flow measurement device of the flue gas flow method, which is used to measure the gas flow flowing through the flue 100. The flue 100 is provided with a plurality of CEMS comparison holes, and each CEMS comparison hole is installed with a flange 200.

[0091] The flue gas flow measurement device comprises a partitioning part 1 and a measuring part 3. The partitioning part 1 is used to be installed in the flue 100 to divide the flue 100 into a plurality of measuring areas 2; the measuring part 3 comprises a measuring component 31 and a calculating component 32, the measuring component 31 is used to extend into the measuring position 20 set in the measuring area 2; the calculating component 32 is used to calculate the gas flow flowing through the flue 100 according to the data measured by the measuring component 31.

[0092] See also Figures 4 to 6 In this embodiment, the partition portion 1 includes a first plate 11 and a second plate 12 which are cross-distributed at a preset angle. The first plate 11 is distributed along the axial direction of the flange 200, and the second plate 12 is arranged between two adjacent flanges 200, so that a plurality of measuring areas 2 are evenly distributed along the axial direction of each flange 200.

[0093] Specifically, in this embodiment, the preset angle is 90°. Of course, in other embodiments, the preset angle may also be set to 75°, 45°, etc., and may be set according to actual needs.

[0094] To facilitate installation of the partition portion 1, in this embodiment, the first plate 11 and the second plate 12 are detachably connected, the second plate 12 is snapped onto the first plate 11 along the flue gas flow upward (Y direction), and the second plate 12 and the first plate 11 are perpendicular to each other.

[0095] It can be known that the number of the first plate 11 and the second plate 12 is set according to the number of measurement areas 2 and the number of flanges 200 to be set. In this embodiment, taking nine measurement areas 2 as an example, two first plates 11 and two second plates 12 are provided, and the first plate 11 is provided with a first card slot 111, and the second plate 12 is provided with a second card slot 121. During assembly, the first card slot 111 and the second card slot 121 cooperate with each other to achieve card connection.

[0096] In order to allow the measuring component 31 of the measuring part 3 to extend to the measuring position 20, the first plate 11 is provided with a through hole 110 for the measuring component 31 to pass through. In this embodiment, the through hole 110 is set to be circular, and the diameter of the through hole 110 can be set according to the measuring component 31, so that the inner wall of the through hole 110 can abut against a part of the measuring component 31, thereby enabling the first plate 11 to support the measuring component 31 to a certain extent.

[0097] Since the measuring components 31 need to measure different measuring areas 2 and avoid mutual interference between the measuring components 31, in another embodiment, the through holes 110 on the first plate 11 can also be arranged according to the structure of the measuring components 31 to ensure the supporting effect of the first plate 11 on the measuring components 31. This is not shown in the figure.

[0098] In this embodiment, the measuring position 20 is arranged in the central area of ​​the measuring area 2. Figure 8 The area indicated by the dotted line.

[0099] See also Figures 7 to 11 In this embodiment, the measuring part 3 and the flange 200 are arranged in a one-to-one correspondence; the measuring part 3 is fixed on the flange 200 corresponding thereto.

[0100] Specifically, the measuring assembly 31 includes a plurality of Pitot tubes 311 arranged corresponding to the measuring positions 20 axially distributed on the flange 200; the lengths of the Pitot tubes 311 of the same measuring part 3 are different, so that the Pitot tubes 311 can extend axially along the flange 200 to the measuring positions 20 corresponding thereto; the Pitot tubes 311 can be arranged as S-type Pitot tubes.

[0101] Furthermore, in order to ensure the stable installation of the Pitot tube 311, the measuring part 3 further includes a supporting fixture 33, which is disposed around the outside of the Pitot tube 311 and is fixedly connected to the Pitot tube 311. The supporting fixture 33 is fixedly connected to the flange 200, and the specific fixed connection method can be welding, bolts and other fasteners, threaded connection, etc.

[0102] Furthermore, in this embodiment, the calculation component 32 can be set as a temperature-pressure-flow integrated device, which can complete the collection and conversion of the pressure signal (measured by the pitot tube 311). Specifically, one end of the pitot tube 211 is fixed on the support fixture 33, and the other end is respectively extended into different measurement areas 2 distributed along the axial direction of the flange 200, which is used to measure the pressure signal when the fluid is flowing, and the pressure signal parameters are converted into electrical signals through the calculation component 32 (temperature-pressure-flow integrated device), and then the corresponding measured flow rate is calculated. Further calculations are performed to obtain the partition flow Q flowing through each measurement area 2 sn , and the overall flow rate Q of the cross section is obtained by summing.

[0103] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A flue gas flow measurement method, for measuring the gas flow flowing through a flue (100), wherein the flue (100) is provided with a plurality of CEMS comparison holes, each of which is provided with a flange (200), It is characterized in that The following steps are involved: Using a partitioning portion (1) to divide a plurality of measurement areas (2) in the flue (100); At least one measuring position (20) is provided in each of the measuring areas (2); The gas flow rate flowing through the flue (100) is measured and calculated through the measuring point (20).

2. A flue gas flow measurement method according to claim 1, It is characterized in that The method of dividing a plurality of measurement areas (2) in the flue (100) by using the partitioning portion (1) specifically comprises the following steps: Selecting a pipe section of the flue (100) provided with the flange (200) as a measuring pipe section (1001); Designing the parameters and installation position of the partition part (1) according to the size of the measuring pipe section (1001) and the installation position of the flange (200) on the measuring pipe section (1001); According to the parameters and the installation position, the partition part (1) is installed in the measuring pipe section (1001) so that a plurality of the measuring areas (2) are evenly distributed along the axial direction of each flange (200).

3. A flue gas flow measurement method according to claim 2, It is characterized in that At least one measuring position (20) is provided in each measuring area (2), and specifically comprises the following steps: The measuring position (20) is arranged on the same cross section (21) of all the measuring areas (2); The measuring position (20) is arranged in the central area of ​​the measuring area (2).

4. A flue gas flow measurement method according to claim 1, It is characterized in that The measuring and calculating of the gas flow rate flowing through the flue (100) by the measuring position (20) comprises: Calculate the measured flow rate of each of the measurement areas (2) Where: K is the flow meter coefficient; ΔP is the differential pressure value measured at the measuring position (20), Pa; ρ is the density of wet flue gas under actual working conditions, kg / m 3 ; Calculate the partition flow Q of each measurement area (2) sn , Where: F is the cross-sectional area of ​​the measurement area; K V is the velocity field coefficient; is the average flow rate of wet flue gas in the cross section, m / s; Q s is the volume flow rate of wet flue gas under actual working conditions, m 3 / h;t s is the flue gas temperature, °C; B a is atmospheric pressure, Pa; P S is the flue gas static pressure, Pa; X SW is the humidity content of flue gas; n is the partition number; For each partition flow Q sn Sum them to calculate the total flue gas flow Q.

5. A flue gas flow measurement method according to claim 4, It is characterized in that The method of measuring and calculating the gas flow rate flowing through the flue (100) by the measuring position (20) further comprises the following steps: Before testing, the velocity field coefficient K V Determination; During the detection process, the velocity field coefficient K is measured at a preset time interval. V Perform calibration.

6. A flue gas flow measurement device based on the flue gas flow measurement method according to any one of claims 1 to 5, used for measuring the gas flow flowing through a flue (100), wherein the flue (100) is provided with a plurality of CEMS comparison holes, each of which is provided with a flange (200), It is characterized in that include: A partitioning portion (1) is used to be installed in the flue (100) to divide the flue (100) into a plurality of measurement areas (2); The measuring part (3) comprises a measuring component (31) and a calculating component (32), wherein the measuring component (31) is used to extend into a measuring position (20) arranged in the measuring area (2); and the calculating component (32) is used to calculate the gas flow rate flowing through the flue (100) based on data measured by the measuring component (31).

7. The flue gas flow measurement device according to claim 6, It is characterized in that The partition portion (1) comprises a first plate (11) and a second plate (12) which are cross-distributed at a preset angle; The first plate (11) is distributed along the axial direction of the flange (200), and the second plate (12) is arranged between two adjacent flanges (200), so that a plurality of measurement areas (2) are evenly distributed along the axial direction of each flange (200).

8. The flue gas flow measurement device according to claim 7, It is characterized in that The first plate (11) and the second plate (12) are detachably connected; and / or, The second plate (12) is clamped onto the first plate (11) in an upward direction along the flow of smoke and is perpendicular to the first plate (11).

9. The flue gas flow measurement device according to claim 6, It is characterized in that The measuring position (20) is arranged in the central area of ​​the measuring area (2).

10. The flue gas flow measurement device according to claim 6 or 9, wherein the measuring part (3) and the flange (200) are arranged in a one-to-one correspondence; The measuring part (3) is fixedly mounted on the corresponding flange (200), and the measuring assembly (31) comprises a plurality of Pitot tubes (311) arranged at the measuring positions (20) distributed axially on the flange (200); The Pitot tube (311) extends axially along the flange (200) to the corresponding measuring position (20); The measuring part (3) further comprises a supporting fixture (33), wherein the supporting fixture (33) is disposed around the outside of the Pitot tube (311) and is fixedly connected to the Pitot tube (311) and the flange (200).

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