Gas Leakage Monitoring Methods and Systems Based on Fixed Locations

Abstract

This invention relates to the field of gas leak monitoring, and discloses a method and system for gas leak monitoring based on fixed points. The method includes: acquiring a captured image of the scene to be monitored using a planar imaging monitor; dividing the captured image into a planar grid, and establishing a lookup table of grid coordinates, grid number, and process block name; identifying the leaking gas based on the captured image, and determining the grid coordinates and corresponding process block name of the leaking gas based on the grid number of the leaking gas, using the lookup table. The technical solution provided by this invention can efficiently, conveniently, in real-time, and accurately detect the location of leak sources.

Description

Technical Field

[0001] This invention relates to the field of gas leak monitoring, specifically to a gas leak monitoring method based on fixed locations, and further, to a gas leak monitoring system based on fixed locations. Background Technology

[0002] Gas leaks in petrochemical plants can cause fires, explosions, and other accidents, posing serious threats to people's lives and property, as well as public safety. Gas leak monitoring is a crucial component in ensuring the safety of petrochemical plants.

[0003] Currently, enterprise gas leak monitoring mainly relies on fixed-point monitoring technology, linear monitoring technology, and area imaging monitoring technology. Fixed-point monitoring technology requires gas to drift to the vicinity of the sensor before triggering an alarm; its detection effectiveness is affected by airflow in open or semi-open spaces, resulting in poor monitoring efficiency and an inability to pinpoint the leak source. Linear detection methods based on principles such as TDLAS have gradually developed, but for spatial gas leaks, multi-line scanning is required to determine the location, leading to poor timeliness. Area imaging gas leak detection technology, due to its advantages of wide coverage, long distance, and intuitive visualization, is gradually becoming an effective means of gas leak detection. Although this technology can achieve machine identification of leaks and mark the gas in the image, manual judgment of the specific leak source location is still required. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned problems in the prior art and provide a new technical solution that can efficiently, conveniently, in real time and accurately detect the location of the leak source, and prevent the leak from causing accidents and serious consequences.

[0005] To achieve the above objectives, a first aspect of the present invention provides a gas leak monitoring method based on a fixed location, the method comprising:

[0006] The scene to be monitored is captured by a surface imaging monitor;

[0007] The captured image is divided into a planar grid, and a lookup table of grid coordinates-grid number-process block name is established;

[0008] Based on the captured footage, the leaking gas is identified, and combined with the lookup table, the grid coordinates and corresponding process block name of the leaking gas are determined according to the grid number where the leaking gas is located.

[0009] Preferably, the area imaging monitor is mounted on a bracket fixed to the scene to be monitored.

[0010] Preferably, the area imaging monitor includes an infrared detector, and the step of identifying the leaked gas based on the captured image includes:

[0011] The infrared video images acquired by the surface imaging monitor are preprocessed to calculate the area S1 of the gas cloud.

[0012] Calculate the ratio P1 of the area of ​​the gas cloud within the planar grid to the area of ​​the grid cell containing it;

[0013] Determine whether a single cell grid has a continuous P1 ≥ set value for a preset time T. If a single cell grid has a P1 ≥ set value for a preset time T, take the number of the single cell grid as the grid number where the leakage source is located.

[0014] Preferably, when multiple unit grids exist in the planar grid at the same time, and P1 ≥ a set value within the preset time T, the number of the unit grid with the largest change in gray value within the preset time T is taken as the grid number where the leakage source is located.

[0015] Preferably, the preset time T is 4s-6s, and the set value is 75%-85%.

[0016] Preferably, the data preprocessing includes: sequentially performing filtering and noise reduction, inter-frame differencing, morphological operations, and contour detection on the infrared video image.

[0017] Preferably, the surface imaging monitor includes an infrared detector, and a filter is added to the front side of the lens group of the infrared detector to achieve narrowband light transmission. The focal length of the lens of the surface imaging monitor is adjustable.

[0018] Preferably, the infrared detector is an uncooled infrared imaging detector, which is used for leak detection of alkane gases or for leak detection of olefin gases.

[0019] Among them, the uncooled infrared imaging detector used for leak monitoring of alkane gases has a response band of 3μm-14μm, an infrared lens focal length of 35mm-45mm, and a high-pass filter band of 7μm-8.7μm.

[0020] The uncooled infrared imaging detector used for leak detection of olefin gases has a response band of 8μm-14μm, an infrared lens focal length of 95mm-105mm, and a high-pass filter band of 10.3μm-10.7μm.

[0021] Preferably, the method further includes sending an alarm signal when a gas leak is detected.

[0022] A second aspect of the present invention discloses a gas leak monitoring system based on a fixed location, the system comprising:

[0023] A surface imaging monitor is used to capture images of the scene to be monitored, thereby obtaining the captured images;

[0024] The lookup table creation module divides the captured image into a planar grid and pre-creates a lookup table of grid coordinates, grid number, and process block name.

[0025] The leak gas identification and location module identifies the leaking gas based on the captured image, and, in conjunction with the lookup table, determines the grid coordinates and corresponding process block name of the leaking gas based on the grid number where the leaking gas is located.

[0026] The technical solution provided by this invention has the following beneficial effects:

[0027] The embodiments of the present invention use a planar imaging monitor to image and monitor the scene to be monitored, thereby avoiding the problem of inaccurate monitoring of leakage sources caused by environmental interference such as atmospheric diffusion, wind speed and wind direction.

[0028] Furthermore, in this embodiment of the invention, the captured image is divided into a planar grid, and a lookup table of grid coordinates, grid number, and process block name is pre-established. Thus, leaking gas can be identified based on the captured image, and the grid coordinates and corresponding process block name of the leaking gas can be determined based on the grid number of the leaking gas in the lookup table. This allows for efficient, convenient, real-time, and accurate detection of the leak source location, preventing leaks from causing accidents and serious consequences. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the process for locating gas leak sources using a planar imaging monitor, provided in an embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram of planar mesh division provided in an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of the leakage source location of a planar imaging monitoring instrument provided in an embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of the leakage monitoring results of Embodiment 1 provided in this invention;

[0033] Figure 5 This is a schematic diagram of the leakage monitoring results of Embodiment 2 provided in this invention;

[0034] Figure 6 This is a structural block diagram of a gas leak monitoring system based on fixed locations provided in an embodiment of the present invention. Detailed Implementation

[0035] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0036] Example 1

[0037] See Figures 1-5 The first aspect of this invention provides a gas leak monitoring method based on a fixed location, the method comprising:

[0038] The scene to be monitored is captured by a surface imaging monitor, thereby obtaining the captured image.

[0039] A surface imaging monitoring device can be installed on a bracket fixed to the scene to be monitored. In other words, the installation position of the surface imaging monitoring device cannot be moved, making it a fixed surface imaging monitoring device.

[0040] See Figure 3 In a preferred embodiment, the area imaging monitor is mounted on a bracket fixed at a specific position via a rotating gimbal. At this fixed position, by controlling the rotation of the rotating gimbal, the area imaging monitor can be controlled to monitor gas leaks at different task points from different visual angles. Different task points correspond to different monitoring scenarios.

[0041] Because a surface imaging monitor is used to image and monitor the scene to be monitored, the problem of inaccurate detection of leakage sources caused by environmental interference such as atmospheric diffusion, wind speed and direction can be avoided.

[0042] The captured image is divided into a planar grid, and a lookup table of grid coordinates, grid number, and process block name is established.

[0043] Specifically, see Figures 2-5 To quickly and accurately determine the location of the leak source, a lookup table of grid coordinates, grid number, and process block name is pre-established. After performing area imaging monitoring on the scene to be monitored, a two-dimensional image can be obtained. This two-dimensional image is then divided into M*N independent regions by planar grid division. Each independent region is numbered to obtain a grid number. Different independent regions have different grid coordinate positions. Each independent grid unit covers typical process blocks within the imaging scene. Thus, a lookup table of grid coordinates, grid number, and process block name can be established.

[0044] It should be noted that when the area imaging monitor is mounted on the fixed bracket by rotating the pan-tilt head, a grid coordinate-grid number-process block name lookup table needs to be pre-established for each different task point. When the area imaging monitor performs gas leak monitoring at different task points, it calls up different grid coordinate-grid number-process block name lookup tables.

[0045] In an optional embodiment, a lookup table of task point-grid coordinates-grid number-process block name can be pre-established. When gas leak monitoring is performed on different task points using a surface imaging monitor, the coordinates and process block name of the gas leak can be directly determined from the lookup table based on the task point and grid number.

[0046] Based on the captured footage, the leaking gas is identified, and combined with the lookup table, the grid coordinates and corresponding process block name of the leaking gas are determined according to the grid number where the leaking gas is located.

[0047] In a preferred embodiment of the present invention, the area imaging monitor can be an infrared imaging monitor. The infrared lens of the infrared imaging monitor has an adjustable focal length to adapt to the image clarity at different monitoring distances. The infrared focal length of the lens group can be adjusted by replacing lenses with different focal lengths using a fixed clip, or by adjusting the focal length using a stepper motor. The infrared detector used in the infrared imaging monitor is preferably an uncooled infrared detector, which can achieve long-term online monitoring. A narrowband filter is added in front of the infrared detector of the infrared imaging monitor to respond to the corresponding spectral absorption band for the gas component to be monitored in a fixed scene, thereby achieving narrowband light transmission.

[0048] Based on the infrared video images captured by the infrared imaging monitor, leaked gas can be identified. Specific identification methods include:

[0049] The infrared video image acquired by the planar imaging monitoring instrument is preprocessed to calculate the area of ​​the gas cloud S1; the proportion P1 of the area of ​​the gas cloud in the planar grid to the area of ​​the unit grid is calculated; it is determined whether there is a single unit grid whose P1 is greater than or equal to a set value for a preset time T. When there is a single unit grid whose P1 is greater than or equal to the set value for the preset time T, the number of the single unit grid is taken as the grid number where the leakage source is located.

[0050] Extensive analysis and testing have verified that the best leakage source localization effect is achieved when the preset interval T is 4s-6s, preferably 5s, and the set value is 75%-85%, preferably 80%.

[0051] Furthermore, the data preprocessing of the infrared video images includes: using filtering to remove noise from the infrared video images acquired by each infrared imaging monitor; performing inter-frame differencing, binarization, and morphological operations on the noise-removed images; determining the gas cloud target through contour detection; marking and rendering the gas cloud; and calculating the area of ​​the gas cloud.

[0052] It should be noted that the simultaneous presence of multiple gas clouds within a planar grid is generally due to large leaks or strong winds causing widespread gas diffusion. Therefore, to accurately locate the leak point, it is necessary to combine the duration of the gas cloud and the grayscale changes in different grid cells to pinpoint the leak source. Specifically,

[0053] When multiple cell grids exist simultaneously in a planar grid, and P1 ≥ a set value within the preset time T, the cell grid number with the largest change in grayscale value within the preset time T is taken as the cell grid number where the leak source is located. This can avoid interference from environmental factors such as atmospheric diffusion, wind speed and direction on gas leak monitoring and improve the accuracy of gas leak monitoring.

[0054] Since a lookup table of grid coordinates, grid number, and process block name has been pre-established, the corresponding process block name and grid coordinates can be quickly found after the grid number is determined. This enables efficient, convenient, accurate, and rapid location of gas leak sources. After obtaining the grid coordinates, grid number, and corresponding process block name of the leak source, this information can be automatically pushed to the operators to prevent leaks from causing accidents and serious consequences.

[0055] The infrared imaging monitor provided in this invention is used to monitor leaked gas. Depending on the type of leaked gas, different filter parameters can be selected to more accurately identify the leaked gas. For example, for alkane leaked gas components, the focal length of the infrared lens of the fixed high-point infrared imaging monitor can be 35mm-45mm, preferably 40mm, the high-pass band of the filter is 7μm-8.7μm, and the response band of the infrared detector is 3μm-14μm, which can clearly identify a target of 0.5m×0.5m in size at a distance of 100m.

[0056] For olefin-based leaked gas components, the infrared lens focal length of the fixed high-point infrared imaging monitor can be 95mm-105mm, preferably 100mm, with a high-pass filter band of 10.3μm-10.7μm and a response band of 8μm-14μm, which can clearly identify targets of 0.5m×0.5m in size at a distance of 300m.

[0057] In a preferred embodiment of the present invention, when a leaking gas is detected and identified by an infrared imaging monitor, an alarm is triggered to indicate the location of the leak source and the name of the process block, including voice alerts, flashing alerts, and display screens, so that operators can quickly repair the leak and prevent it from causing an accident that could lead to serious consequences.

[0058] The gas leak monitoring method based on fixed locations provided by the present invention will be described below with reference to two specific embodiments.

[0059] Example 2

[0060] See Figure 3 An infrared imaging monitor was used for high-point imaging monitoring of an alkane tank area. The infrared imaging monitor was located on a rotating pan-tilt unit mounted on a fixed support. The infrared imaging monitor was an uncooled infrared imaging detector with a response band of 3μm-14μm and a high-pass filter band of 7μm-8.7μm. Based on the on-site monitoring requirements, different task points were established. For each task point, a corresponding pan-tilt angle and infrared lens focal length were set, and the pan-tilt angle was matched with the actual monitoring scene. The monitoring scene image corresponding to each pan-tilt angle was divided into grids, and the coordinate information of the grids in the imaging image was calibrated, matched with the actual scene blocks, and numbered. Each independent grid cell covered a typical process block within the imaging scene, and a lookup table of task point-grid coordinates-grid number-process block name was established. The pan-tilt rotation angle and infrared lens focal length were controlled. The communication component uploaded the pan-tilt rotation position information and the gas infrared imaging monitoring and identification results. (See reference...) Figure 4 At task point 1, with the pan-tilt unit rotated at (-30°, 20°), aim at the top of tank #3. The infrared imaging detector has a resolution of 320×240, dividing the fixed scene within the field of view into 5×5 grids. The grids are numbered 1-25 sequentially from left to right and top to bottom, starting from the upper left corner of the field of view. When imaging and monitoring the breather valve on the tank top within the fixed scene, refer to the grid outlined in black in section 4. Grid number 17 shows a continuous gas leak and its area within the grid is ≥80%. An alarm is triggered indicating a gas leak. The leak source is at task point 1 (-30°, 20°), tank top of tank #3 - coordinate position (144, 64) - grid number 17 - breather valve port.

[0061] Example 3

[0062] See Figure 4 The infrared imaging monitor is installed at a fixed high point, aimed at the top of the storage tank. The infrared imaging detector has a resolution of 320×240. The fixed scene within the field of view is divided into 5×5 grids, numbered 1-25 sequentially from left to right and top to bottom, starting from the upper left corner of the field of view. When imaging and monitoring the breather valve on the tank top within the fixed scene, grid number 17 shows a continuous gas leak with an area ≥80% of the grid area. An alarm is triggered indicating a gas leak. The leak source coordinates are (144, 64), grid number 17, at the breather valve port. For the specific location, please refer to [link to relevant documentation]. Figure 4 The grid is defined by a black border.

[0063] Example 4

[0064] See Figure 5An infrared imaging device is fixedly installed. Gas leakage is simulated by releasing gas from an 8L gas cylinder. The monitoring distance is 10m, the gas volume concentration is 99.9%, the flow rate is 35L / min, and the infrared imaging detector resolution is 320×240. The fixed scene within the field of view is divided into 8×10 grids, numbered 1-80 sequentially from left to right and top to bottom, starting from the upper left corner of the field of view. When imaging the fixed scene, if multiple grids continuously exhibit gas leakage and their area within the grid is ≥80%, the difference in grayscale value change ΔG within the grids with ≥80% coverage is compared. The grid with the largest ΔG is selected as the leakage source area, triggering an alarm to detect gas leakage. The leakage source coordinates are (90, 192), numbered 37, located at the outlet of the gas cylinder output pipeline. For the specific location, see [link to relevant documentation]. Figure 5 The grid is defined by a black border.

[0065] Example 5

[0066] See Figure 6 Based on the gas leak monitoring method based on a fixed location provided in the first aspect of the present invention, the second aspect of the present invention provides a gas leak monitoring system based on a fixed location, the system comprising:

[0067] The area imaging monitor includes an infrared detector, with a filter installed in front of the lens group of the infrared detector. The detector is preferably an uncooled infrared imaging detector. The monitor is fixedly installed on a bracket in the scene to be monitored and is used to capture images of the scene to be monitored.

[0068] The lookup table creation module (not shown in the figure) divides the captured image into a planar grid and pre-creates a lookup table of grid coordinates, grid number, and process block name.

[0069] The leak gas identification and location module includes a gas target identification module and a leak source location module. The gas target identification module identifies the leaking gas based on the captured image, and the leak source location module, in conjunction with the lookup table, determines the grid coordinates and corresponding process block name of the leaking gas based on the grid number where the leaking gas is located.

[0070] In a preferred embodiment of the present invention, the gas leak monitoring system based on fixed points further includes an alarm module. The alarm module is used to issue an alarm signal when a leaking gas is detected, and push the grid coordinates, grid number, process block name, etc. monitored by the leak source location module.

[0071] For more specific technical details of the gas leak monitoring system based on fixed locations provided in the second aspect of the present invention, please refer to the gas leak monitoring method based on fixed locations described in the first aspect of the present invention, which will not be repeated here.

[0072] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention. This includes combining various specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not further describe the various possible combinations. However, these simple modifications and combinations should also be considered as part of the content disclosed in this invention and are all within the protection scope of this invention.

Claims

1. A gas leak monitoring method based on fixed locations, characterized in that: The method includes: The scene to be monitored is captured by a surface imaging monitor; The captured image is divided into a planar grid, and a lookup table of grid coordinates-grid number-process block name is established; Based on the captured footage, the leaking gas is identified, and in conjunction with the lookup table, the grid coordinates and corresponding process block name of the leaking gas are determined according to the grid number where the leaking gas is located. The surface imaging monitor includes an infrared detector, and the step of identifying leaked gas based on the captured image includes: The infrared video images acquired by the surface imaging monitor are preprocessed to calculate the area S1 of the gas cloud. Calculate the ratio P1 of the area S1 of the gas cloud within the planar grid to the area of ​​the corresponding cell grid. Determine whether a single cell grid has a continuous P1 ≥ set value for a preset time T. If a single cell grid has a P1 ≥ set value for a preset time T, take the number of the single cell grid as the grid number where the leakage source is located. When multiple cell grids exist in a planar grid at the same time, and P1 ≥ the set value within the preset time T, the cell grid number with the largest change in gray value within the preset time T is taken as the cell grid number where the leakage source is located. The preset time T is 4s-6s, and the set value is 75%-85%.

2. The gas leak monitoring method based on fixed points according to claim 1, characterized in that, The area imaging monitoring device is mounted on a bracket fixed to the scene to be monitored.

3. The gas leak monitoring method based on fixed points according to claim 1, characterized in that, The data preprocessing includes sequentially performing filtering and noise reduction, inter-frame differencing, morphological operations, and contour detection on the infrared video image.

4. The gas leak monitoring method based on fixed points according to claim 1, characterized in that, The surface imaging monitoring instrument includes an infrared detector, and a filter is added to the front side of the lens group of the infrared detector to achieve narrow-band light transmission. The focal length of the lens of the surface imaging monitoring instrument is adjustable.

5. The gas leak monitoring method based on fixed points according to claim 4, characterized in that, The infrared detector is an uncooled infrared imaging detector, which is used for leak detection of alkane gases or olefin gases. Among them, the uncooled infrared imaging detector used for leak monitoring of alkane gases has a response band of 3μm-14μm, an infrared lens focal length of 35mm-45mm, and a high-pass filter band of 7μm-8.7μm. The uncooled infrared imaging detector used for leak detection of olefin gases has a response band of 8μm-14μm, an infrared lens focal length of 95mm-105mm, and a high-pass filter band of 10.3μm-10.7μm.

6. The gas leak monitoring method based on fixed points according to claim 1, characterized in that, The method also includes sending an alarm signal when a gas leak is detected.

7. A gas leak monitoring system based on fixed locations, characterized in that, The system includes: A surface imaging monitor is used to capture images of the scene to be monitored, thereby obtaining the captured images; The lookup table creation module divides the captured image into a planar grid and pre-creates a lookup table of grid coordinates, grid number, and process block name. The leak gas identification and positioning module identifies the leaking gas based on the captured image, and, in conjunction with the lookup table, determines the grid coordinates and corresponding process block name of the leaking gas based on the grid number where the leaking gas is located. The surface imaging monitor includes an infrared detector, and the step of identifying leaked gas based on the captured image includes: The infrared video images acquired by the surface imaging monitor are preprocessed to calculate the area S1 of the gas cloud. Calculate the ratio P1 of the area S1 of the gas cloud within the planar grid to the area of ​​the corresponding cell grid. Determine whether a single cell grid has a continuous P1 ≥ set value for a preset time T. If a single cell grid has a P1 ≥ set value for a preset time T, take the number of the single cell grid as the grid number where the leakage source is located. When multiple cell grids exist in a planar grid at the same time, and P1 ≥ the set value within the preset time T, the cell grid number with the largest change in gray value within the preset time T is taken as the cell grid number where the leakage source is located. The preset time T is 4s-6s, and the set value is 75%-85%.

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