Detection method for spray test of absorption tower of wet flue gas desulfurization system

Abstract

The invention provides a detection method for a spray test of an absorption tower of a wet flue gas desulfurization system. The detection method comprises the following steps: acquiring arrangement information of nozzles in each layer of spray area of the absorption tower; determining an unmanned aerial vehicle flight path of each layer of spraying area according to the arrangement information of the nozzles in each layer of spraying area; the unmanned aerial vehicle collects spraying image information of each nozzle in the spraying area layer by layer from bottom to top according to the unmanned aerial vehicle flight path of each layer of spraying area; and positioning the position to be detected according to the spraying effect represented by the spraying image information and the arrangement information of the corresponding nozzles. According to the embodiment, the flight path of the unmanned aerial vehicle is determined by determining the arrangement information of the nozzles, so that the unmanned aerial vehicle can pass through each nozzle, and the spraying image information of each nozzle can be collected. And the spraying effect is judged by analyzing the spraying image information, and the position to be detected is positioned by combining the arrangement information of the corresponding nozzles. In this way, the position to be detected is directly provided for workers, and the maintenance efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of absorption tower spray detection, in particular to a detection method for a wet flue gas desulfurization system absorption tower spray test. Background Art

[0002] At present, limestone-gypsum wet flue gas desulfurization system is widely used in flue gas desulfurization at home and abroad. Among them, the absorption tower slurry spray system is a very important core system in the whole desulfurization system. It is mainly composed of slurry circulation pump, spray pipe and nozzle. The spray layer of the spray system is arranged in the absorption tower of the desulfurization system. Under the power of the slurry circulation pump, the slurry is transported to each nozzle according to the main pipe and branch pipe of the spray layer pipeline. The spray and flue gas generated by the spray react with the coverage area up to 300% countercurrently, thereby absorbing sulfur dioxide in the flue gas.

[0003] If the spraying effect of the spray layer nozzle does not reach the design value, the output of the slurry circulation pump will inevitably decrease, thereby reducing the efficiency of the desulfurization system, further affecting the increase in energy consumption of various indicators of the desulfurization system, and may also cause unplanned shutdown of the unit.

[0004] Each time before the manhole door of the desulfurization system is closed, a spray test is required to verify the maintenance effect and to identify potential hidden dangers to the greatest extent. Therefore, a mature and reliable desulfurization system absorber spray effect test method is particularly important.

[0005] The traditional routine manual inspections mainly include: ① Observe and accept the spraying effect at the manhole door of the spray layer corresponding to the absorption tower; ② Inspectors use telescopes to observe and accept the spraying effect at the manhole door of the spray layer corresponding to the absorption tower; ③ Set up scaffolding on each layer of spray pipes, and personnel wear raincoats to enter the interior for observation and acceptance of the spraying effect.

[0006] The above inspection method is not only affected by the dark light inside the absorption tower and the closed space and cannot fully cover the spray test effect, but also requires a lot of manpower and financial resources, and poses a huge hidden danger to the personal safety of the acceptance personnel, and also lays a huge hidden danger to the effect judgment.

[0007] The following is an actual engineering case to illustrate the shortcomings of conventional detection methods.

[0008] Taking the spray test inspection of the desulfurization system of a long-cycle operating unit in a power plant as an example, the main faults are: the desulfurization efficiency did not reach the design value, the current of 7 slurry circulation pumps and the spray layer did not return to the design current after maintenance, and the output showed a gradual downward trend until all 7 circulation pumps were in operation and the total outlet SO2 exceeded the standard. After the shutdown, the nozzle inspection found that the spray pipe near the inside (not at the manhole door of each spray layer) was seriously blocked (the blockage rate was as high as 50%). The reason for the blockage was that the spray branch pipe and the nozzle did not thoroughly clean the scaling attached to the inner wall during the dredging process. At the beginning of the operation of the spray system, the spray effect or coverage area of ​​some nozzles near the inner side of the absorption tower did not reach the design value, and it was not discovered and repaired in time during the spray test inspection and acceptance, which led to the scaling attached to the inner wall of the unit after operation. The scaling could not be flushed out in time, but further scaled with acidic gypsum, which eventually caused the desulfurization efficiency to gradually decrease, affecting the safe and stable operation of the unit. Summary of the invention

[0009] The content of the present invention is used to introduce the concepts in a brief form, which will be described in detail in the detailed implementation section below. The content of the present disclosure is not intended to identify the key features or essential features of the technical solution claimed for protection, nor is it intended to limit the scope of the technical solution claimed for protection.

[0010] Some embodiments of the present invention provide a detection method for a spray test of an absorber in a wet flue gas desulfurization system to solve the technical problems mentioned in the above background technology section.

[0011] The method includes obtaining arrangement information of nozzles in a spraying area of ​​each layer of an absorption tower;

[0012] Determine the flight path of the drone in each spraying area according to the arrangement information of the nozzles in each spraying area, so that the drone passes through each nozzle;

[0013] The drone collects the spray image information of each nozzle in the spray area layer by layer from bottom to top according to the drone flight path of each spray area;

[0014] The position to be inspected is located according to the spraying effect represented by the spraying image information and the arrangement information of the corresponding nozzles.

[0015] The above-mentioned embodiment of the present invention has the following beneficial effects: by determining the arrangement information of the nozzles, the flight path of the drone is determined, so that the drone can pass through each nozzle, and thus the spray image information of each nozzle can be collected. Then, by analyzing the spray image information, the spray effect is judged, and then the position to be inspected is located in combination with the arrangement information of the corresponding nozzle.

[0016] In this way, the position to be inspected can be located comprehensively and accurately, avoiding poor nozzle atomization effect due to poor maintenance, resulting in low desulfurization efficiency.

[0017] In addition, it also provides a direct maintenance location for the staff, improving maintenance efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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.

[0019] Figure 1 Flow charts of some embodiments of the detection method of the wet flue gas desulfurization system absorption tower spray test according to the present disclosure;

[0020] Figure 2 A schematic diagram of an embodiment of a UAV flight path of the present invention;

[0021] Description of reference numerals:

[0022] 1: Absorption tower; 2: Spray main pipe; 3: Spray branch pipe; 4: Nozzle; 5: Manhole;

[0023] 6: Drone flight path. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than 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.

[0025] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0026] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, 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 connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0028] See also Figure 1 and Figure 2 , Figure 1 The process 100 of some embodiments of the detection method of the wet flue gas desulfurization system absorption tower spray test according to the present disclosure is as follows: Figure 2 FIG. 1 is a schematic diagram of an embodiment of the UAV flight path of the present invention. Figure 1 As shown, the detection method comprises the following steps:

[0029] Step 101: Obtain the layout information of the nozzles in the spray area of ​​each layer of the absorption tower.

[0030] In some embodiments, Figure 2 As shown, the absorption tower 1 is usually provided with multiple layers of spraying areas in the vertical direction. Figure 2 As shown, each layer of the spraying area is provided with a spraying main pipe 2, and a plurality of spraying branch pipes 3 are connected to the spraying main pipe 2. The spraying branch pipes 3 are usually arranged perpendicular to the spraying main pipe 2. A plurality of nozzles 4 are arranged on each spraying branch pipe 3. In the detection method of the present invention, the nozzles 4 arranged downward, that is, the nozzles 4 spraying downward, are applicable. The spraying main pipe 2 is also connected to the slurry circulation pump through a feed pipe. In the working state, the slurry circulation pump transports the slurry to the spraying main pipe 2, so that the slurry is sprayed downward from the nozzle 4 to form a spraying area, thereby reacting with the flue gas. Therefore, if the spraying branch pipe 3 or the nozzle 4 is blocked, the spraying effect of the spraying area will be affected, thereby reducing the desulfurization efficiency.

[0031] The arrangement information of the nozzles may include elevation information, position information and number information, which respectively represent the setting height of the nozzles, the position of the nozzles and the number of the nozzles. The arrangement information of the nozzles may be obtained from the design drawings during construction. The elevation of the nozzles, the spacing between multiple nozzles and the position of the nozzles in the cross section of the absorption tower are usually marked in the design drawings.

[0032] In addition, the layout of the nozzles can be constructed by flying a drone over each spray area. For example, the drone can be equipped with image acquisition devices such as laser radar, stereo cameras, and image processing terminals. First, the drone collects nozzle data through laser radar and stereo cameras. For example, the image is collected by a stereo camera, and the image processing terminal extracts features from the image and determines the position of the nozzle. The laser radar determines the position of the drone in the spray area. Through the 3DSLAM algorithm, a three-dimensional model of the spray area is created, and the positioning accuracy is optimized by matching features, so as to construct a detailed nozzle layout diagram. The elevation and position of each nozzle can also be marked in the layout diagram.

[0033] like Figure 2 As shown, when setting the number of the nozzle 4, the spray area of ​​each layer can be first numbered, for example, the spray area of ​​the bottom layer can be 1, and the top layers can be 2, 3, etc. Then, the spray branch pipes 3 can be numbered in the second level along the first direction. Specifically, the first direction can be from left to right ( Figure 2 The first direction may also coincide with the axial direction of the spray main pipe 2. The spray branch pipe 3 at the leftmost end may be numbered 1, and the nozzles 4 on each spray branch pipe 3 may be numbered three levels along the second direction. The second direction may coincide with the axial direction of the spray branch pipe 3. The second direction may be from bottom to top ( Figure 2 In the direction of the spray branch pipe 3, if one side of the spray branch pipe 3 is provided with a nozzle 4, the nozzle 4 at the bottom can be numbered 1, and the nozzles 4 at the top can be numbered 2, 3, etc. Therefore, the numbering of the nozzles 4 at the bottom of the bottom layer can be 1-1-1. Figure 2 As shown, nozzles 4 are arranged on both sides of the spray branch pipe 3, and the two nozzles 4 at the bottom can be numbered 1-1 and 1-2 from left to right, and the nozzle 4 at the bottom left of the bottom layer can be numbered 1-1-1-1.

[0034] Step 102, determining the flight path of the drone in each spraying area according to the arrangement information of the nozzles in each spraying area, so that the drone passes through each nozzle.

[0035] In some embodiments, the design drawings reflecting the arrangement information of the above-mentioned nozzles or the layout diagram constructed by the drone can be used through the processing terminal of the drone to plan the flight path of the drone using, for example, a reverse incremental motion algorithm. Of course, it is also possible that the staff determines the flight path of the drone by using the simulation software including the above-mentioned algorithm on the design drawings or the layout diagram constructed by the drone, and then inputs the flight path of the drone into the drone. The purpose is that the drone can pass through each nozzle through the above-mentioned flight path, and then collect the spray image information of each nozzle.

[0036] In some optional implementations, the above drone flight path can be set by the following steps:

[0037] First, if Figure 2 As shown, the position of the manhole 5 of each layer of the absorption tower is determined, and the manhole 5 is used as the starting point of the UAV flight path 6. The manhole 5 is an entrance for servicing the nozzles 4 of each layer, and the staff can enter through the manhole 5. Therefore, the manhole 5 is used as the entrance for the UAV to enter the nozzle 4, that is, the starting point of the UAV flight path 6.

[0038] The UAV flight path 6 extends upward from the starting point along the travel channel between the two spray branches 3 until the UAV flight path 6 is less than the preset distance from the inner wall of the front absorption tower 1, indicating that it is approaching the inner wall of the absorption tower 1. At this time, the UAV flight path 6 crosses to the left side of the travel channel ( Figure 2 direction in the middle).

[0039] As mentioned above, the drone flight path 6 then extends in an S shape to all travel paths on the left side of the above-mentioned travel path.

[0040] The UAV flight path 6 crosses the travel channel on the right side of the above travel channel ( Figure 2 In the direction of the middle path), continue to extend all the travel channels on the right side of the above travel channel in an S shape, and finally return to the starting point.

[0041] Furthermore, in order to ensure the reliability of the drone flight path 6, after determining the drone flight path 6, the drone can be made to perform a test flight according to the drone flight path 6, and take a photo of the nozzle 4 or record a video to collect the image information of the nozzle 4, and transmit the image information to the display terminal, and the staff will judge whether the image information is qualified. Of course, the above image information can also be compared with the image information of the sample nozzle in the database of the drone through the image processing terminal of the drone to determine whether the image information is qualified. If it is unqualified, the position of the nozzle is determined by the numbering information, so as to adjust the above drone flight path.

[0042] Step 103 , the drone collects spray image information of each nozzle in the spray area layer by layer from bottom to top according to the drone flight path of each spray area.

[0043] In some embodiments, the slurry circulation pump corresponding to the lower spray layer is first started so that the slurry is sprayed out from the nozzle of the lowest layer until the slurry circulation pump reaches the set power, or a flow meter is set on the above-mentioned pipeline branch until the value of the flow meter reaches the preset flow.

[0044] Next, the drone enters the corresponding manhole and collects the spray image information of each nozzle according to the drone flight path. It should be noted that the drone can take off from a drone landing platform placed on the ground, fly to a matching height according to the elevation information of the bottom manhole, and then enter the manhole. The above-mentioned drone landing platform can also be set to the platform where the manhole is located, and technicians in this field can choose according to actual conditions.

[0045] The image processing terminal of the above-mentioned UAV can use a multi-channel fusion algorithm and a time-varying parameter estimation algorithm to fuse the spray image information, reduce the impact of image differences and motion compensation, eliminate the nonlinear errors and distortions of the system, and improve the resolution, accuracy and stability of the image.

[0046] Step 104 , locating the position to be inspected according to the spraying effect represented by the spraying image information and the arrangement information of the corresponding nozzles.

[0047] In some embodiments, the coverage area of ​​each nozzle spray is determined by an edge extraction method of image processing. The above coverage area is compared with the sample coverage area image in the database of the drone. When the coverage area is equal to or greater than the sample coverage area, that is, the coverage area reaches a preset threshold, it indicates that the nozzle and the spray branch pipe at this position are not blocked and the spray effect is qualified. The spray image information can be stored in the drone database as a new sample coverage area image.

[0048] If the coverage area is smaller than the sample coverage area, the nozzle and the spray branch pipe at the position are blocked, the spray effect is unqualified, and the nozzle corresponding to the spray image information is determined as the position to be inspected. The position to be inspected includes the corresponding nozzle and the spray branch pipe.

[0049] The position to be inspected corresponding to the spray image information is determined by the number information of the nozzle. Specifically, the flight time when the drone takes the spray image information can be collected to determine the position of the drone in the flight path of the drone, and then the nozzle number information can be determined by the above position.

[0050] In some optional implementations of the embodiments, the spray image information with unqualified coverage area and the number information of the corresponding nozzle can also be extracted and synthesized into one image, that is, an image including the spray image information and the image marked with the number information. The image is transmitted to the display end of the control room for analysis by the staff. Furthermore, a corresponding relationship table between the number information of the above-mentioned nozzles and the corresponding spray image information can be formed to form a maintenance record, which can be used for guidance during the construction process, can be retained after the construction is completed, and can be fed back to the design link, which is a very valuable reference material.

[0051] The above is an explanation of testing the spray area on the bottom layer. After that, the valves can be opened layer by layer upwards to test the spray areas on the upper layers layer by layer.

[0052] The staff repairs and replaces the nozzle or spray branch pipe based on the spray image and number information. The spray image information of the nozzle is collected again by the drone, and the staff determines whether the location has been repaired and the spray effect is normal based on the spray image information. If everything is normal, the inspection can be completed and the manhole can be closed.

[0053] Combined with the actual project, the detection method of the present invention is further explained. Taking the maintenance of the spray system of the absorption tower of a 350MW unit as an example, the 4-layer spray nozzles and branch pipes are seriously blocked. Before each start of the unit, it can only be observed at the manhole door according to the conventional spray test. The observation effect is very good. As a result, the performance of the unit does not reach the design value after operation. After a long period of operation, the slurry gradually deteriorates, the gypsum becomes thin, and the on-site environment is polluted. The power consumption and stone consumption rate are high. The detection method of the present invention not only reduces the blind evaluation of the spray test effect, but also can accurately locate the nozzle atomization effect, avoiding the problems of low desulfurization efficiency and even non-stop caused by poor maintenance of the nozzle atomization effect, thereby ensuring that the slurry circulation pump reaches the design value and operates stably, achieving the purpose of saving power consumption and equipment loss and improving desulfurization efficiency.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A detection method for a spray test of an absorber in a wet flue gas desulfurization system, the method comprising: Obtain the layout information of the nozzles in the spray area of ​​each layer of the absorption tower; Determine the flight path of the drone in each spraying area according to the arrangement information of the nozzles in each spraying area, so that the drone passes through each nozzle; The drone collects the spray image information of each nozzle in the spray area layer by layer from bottom to top according to the drone flight path of each spray area; The position to be inspected is located according to the spraying effect represented by the spraying image information and the arrangement information of the corresponding nozzles.

2. The detection method of the wet flue gas desulfurization system absorption tower spray test according to claim 1 is characterized in that: The layout information includes elevation information, location information and numbering information.

3. The detection method of the wet flue gas desulfurization system absorption tower spray test according to claim 2 is characterized in that: The numbering information of the nozzles in the spray area is set by the following steps: Each layer of spray area is numbered at the first level; Secondary numbering of the spray branch pipes in each spray area along a first direction, wherein the first direction coincides with the axis of the spray main pipe in the spray area of ​​the layer; The nozzles on each spray branch pipe are numbered in three levels along a second direction, and the second direction coincides with the axis of the spray branch pipe.

4. The detection method of the wet flue gas desulfurization system absorption tower spray test according to claim 2 is characterized in that: The flight path of the UAV in each spraying area is determined according to the arrangement information of the nozzles in each spraying area, so that the UAV passes through each nozzle, including: Determine the starting point of the flight path of the drone according to the manholes on each floor of the absorption tower; The flight path of the drone extends along the travel channel between the two spray branches at the starting point, and after being less than a preset distance from the inner wall of the absorption tower, crosses to the travel channel adjacent to the first side of the travel channel; After the UAV flight path extends to all travel channels on the first side of the travel channel, it crosses to the travel channel adjacent to the second side of the travel channel; After the UAV flight path extends to all travel channels on the second side of the travel channel, it returns to the starting point.

5. The detection method of the wet flue gas desulfurization system absorption tower spray test according to claim 4 is characterized in that: Determine the flight path of the drone in each spraying area according to the arrangement information of the nozzles in each spraying area so that the drone passes through each nozzle, and also include: The UAV conducts a test flight according to the UAV flight path to determine whether the image information collected from each nozzle is qualified; If not, adjust the flight path of the drone.

6. The detection method of the wet flue gas desulfurization system absorption tower spray test according to claim 2 is characterized in that: The drone collects the spray image information of each nozzle in the spray area layer by layer from bottom to top according to the drone flight path of each spray area, including: Start the slurry circulation pump to spray the spray area layer by layer from bottom to top; In response to the slurry circulation pump reaching a set power, the drone reaches a corresponding manhole according to the elevation information; The UAV collects the spray image information of each nozzle according to the UAV flight path of the spray area of ​​that layer.

7. The detection method of the wet flue gas desulfurization system absorption tower spray test according to claim 2 is characterized in that: According to the spraying effect represented by the spraying image information and the arrangement information of the corresponding nozzles, the position to be inspected is located, including: Determine whether the coverage area of ​​the nozzle spray in the spray image information is equal to or greater than a preset threshold; If yes, the spray image information is stored in the drone database.

8. The detection method of the wet flue gas desulfurization system absorption tower spray test according to claim 2 is characterized in that: According to the spraying effect represented by the spraying image information and the arrangement information of the corresponding nozzles, the position to be inspected is located, including: Determine whether the coverage area of ​​the nozzle spray in the spray image information is less than a preset threshold; If so, the nozzle corresponding to the spray image information is determined as the position to be inspected.

9. The detection method of the wet flue gas desulfurization system absorption tower spray test according to claim 8, characterized in that: After locating the position to be inspected according to the spraying effect represented by the spraying image information and the arrangement information of the corresponding nozzles, the method further includes: Extract the spray image information and the number information of the corresponding nozzle at each layer of the position to be inspected; The spray image information and number information of the positions to be inspected on the same layer are synthesized into one image and transmitted to the display end.

10. The detection method of the wet flue gas desulfurization system absorption tower spray test according to claim 9, characterized in that: After the spray image information and number information of the nozzles to be inspected on the same layer are synthesized into one image and transmitted to the display end, the following is also included: In response to the location to be inspected being repaired, the drone collects spray image information of the nozzle at the location; According to the spray image information, it is determined whether the location is qualified for maintenance.

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