JP2687466B2 - How to estimate the location of gas leaks - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a method for estimating a location where gas is leaking. The method of the present invention is useful for danger prevention, particularly in industrial plants handling flammable or toxic gases. Here, the term "gas" means a vapor of a volatile liquid in addition to a substance that is normally in a gaseous state, and in the following description, this term is representative of both. “Leakage” means leakage from a part where gas should not go out, such as a pipe flange, due to deterioration or damage of the material, and release into the atmosphere such as a stack. It includes both the case where the discharge occurs from the outlet due to an erroneous operation or a sudden cause.

[Prior art]

For example, in various plants of the petrochemical industry, various combustible and toxic gases flow through piping and various facilities, and there is always a risk of leakage. Therefore, when there is a leak, it is necessary to quickly find the place and take safety measures to prevent a secondary disaster. For the purpose of knowing gas leakage, a gas detector is installed at some suitable locations in a plant. As a technique for estimating a gas leak location in a plant using a gas detector, a method has been proposed on the premise that at least three gas detectors detect gas (JP-A-61-155932). ). This method identifies the three points with the highest gas concentration under virtually no wind, and determines the ratio of the distance between the highest gas concentration point and the other two points to the virtual leak source. Then, the gas leakage source is estimated from this virtual leakage source. In windy conditions, three points with the highest gas concentration are also identified, the distance between the highest gas concentration point and the next highest concentration is determined, and the ratio of the gas concentration to the distance is used to determine the gas leakage. Estimate the source. However, in an actual industrial plant, the distance between installed gas detectors is relatively long, and the gas detectors are scattered only in a large site. This is because the number of installations is calculated on the basis of the number obtained by dividing the perimeter of the facility that handles hazardous gases indoors by 10m when it is indoors, and by 20m when it is outdoors. This is because it is often arranged so as to surround the above equipment. By the time the gas is detected at three or more different points under such conditions, gas leakage will progress to a considerable extent, and
A considerable amount of time will pass. Therefore, the above method is unsatisfactory from the viewpoint of promptly finding the gas leakage location and taking safety measures.
The intention to minimize the effects of leakage, including prevention of secondary disasters, cannot be achieved.

[Problems to be solved by the invention]

An object of the present invention relates to estimation of a dangerous gas leak location in an industrial plant, and it is possible to quickly estimate the leak location by solving the problems of the prior art, thereby promptly taking safety measures. The object of the present invention is to provide a method for estimating the location of gas leakage that makes it possible.

[Means for Solving the Problems]

According to the present invention, when a gas leak occurs in a plant, the method for estimating the leak location is characterized by the following steps: a) Wind direction and wind speed data are continuously collected and recorded. B) When at least one gas detector detects leaking and diffusing gas, using the above wind direction and wind speed data, the average fluctuation of the wind direction within a certain period of time traces back to the time when the gas was detected. And calculating the diffusion width of the gas that is diffusing, c) Adding the average swing width of the wind direction and the diffusion width of the gas to the wind direction at the time of detection, and detecting the leak pull the two straight lines around the detector represents the angle, to define the upwind direction of a region B _1, d) have been installed around the gas detector which detects the leakage, the at least one Scan detector of the other gas detector that has not detected the gas upon detection of a gas, is formed by two straight lines of the same angle to the upwind direction with respect to those in the region B ₁ Defining a region B ₂ , and e) a region where the remaining region B ₃ after the region B ₂ is removed from the region B ₁ overlaps with the region A where facilities for handling gas to be gas-detected are installed. Ask for B ₄ .

[Operation]

A method for estimating a gas leakage location according to the present invention will be described with reference to the drawings. First, a system used for implementing this method is typically constructed as shown in FIG. In FIG. 1, 1A, 1B, 1C, ... 1M are gas detectors (indicated by X in FIGS. 1 and 3 in the figure) placed on the site of the industrial plant, and 2 is also on the site of the plant. The wind direction and anemometer installed in the instrument constantly measures the gas concentration, wind direction, and wind speed. The measurement data is always transmitted as an analog signal, and 3A, 3
B, ... 3M, 3N are converted into digital signals in the A / D conversion device, and the central processing unit 5 is passed through the data acquisition device 4.
It is taken in. Further, these data are stored in the storage device 6.
Will be recorded. The position coordinates of the gas detectors 1A to 1M and the position coordinates of the facility that handles the gas to be detected are input and stored in the storage device through the keyboard 7 in advance. Now, assuming that any one of the gas detectors 1A to 1M detects a gas having a concentration higher than a specified concentration, the detection signal is sent to the central processing unit 4, and the central processing unit 4 receives the wind direction obtained from the wind direction anemometer 2. The location of gas leakage is estimated using the wind velocity zeta and the position coordinate data stored in the storage device 6, and the result is displayed on the CRT display device 8 and output to the printer 9. When the anemometer data exceeds the above-mentioned fixed limit and a certain amount of wind is blowing, as shown in FIG. 2A, the gas leaking at the point X and diffusing in the atmosphere The isoconcentration region is in the form of a spindle-shaped plume (air mass) shown by diagonal lines in the steady state. When this is detected by the gas detector 1Y, first, a region in which a gas leakage source that brings about the above-mentioned gas isoconcentration region may exist is obtained in this detector. Based on the wind direction data collected and recorded, as shown in Fig. 3,
Calculate the average width of the wind direction within a fixed time dating back to the detection time, calculate the diffusion width of the gas based on the wind speed data, centering on the wind direction at the time of gas detection, to the average width of the wind direction. An angle obtained by adding the gas diffusion width is obtained, and this is used as an angle representing the azimuth and width of the gas diffusion region. Here, the reason for averaging the wind direction for a certain period of time before the detection time is that the wind direction always changes within a short period of time. The mean value of the minutes is that the estimation accuracy is higher. When the angle representing the azimuth and width of the gas diffusion region is determined as described above, the center of the angle is adjusted to the position of the detector 1Y that has detected the gas, as shown in FIG. 2B. Draw two straight lines, and find the area B ₁ between the two straight lines in the windward direction. This region B ₁ is a region where the gas detector 1Y may detect gas when a leak occurs in it. Next, with respect to other gas detectors in the range of the region B ₁ and not detecting gas, two straight lines representing the above angles are drawn, respectively, and are sandwiched by the two straight lines on the windward side of those detectors. Find the area B ₂ . This region B ₂ is a region where there is no possibility of gas leakage because the gas detector there does not detect gas. In other words, the possibility that the gas is leaking is that B ₃ remains after excluding the region B ₂ from the region B ₁ as seen in FIG. 2C. On the other hand, gas leakage cannot occur in the absence of equipment that handles the gas, so there is a possibility of leakage by overlapping area A with the equipment with area B ₃ obtained as described above. Excludes the part without. As shown in FIG. 2D, the gas leak point X is present in the region B ₄ thus obtained, and the gas leak location is limited. Further, over time, gas may be detected by multiple gas detectors.In that case, the gas leak location should be estimated using the same procedure as described above for the second and third detectors. By repeating, the range can be narrowed further. As shown in FIG. 2E, when the detectable concentration range of the diffusion gas, etc. reaches the detector 1Z, the above estimation is performed for it and the overlap with the estimated range of the detector 1Y is obtained. The gas leakage location can be narrowed down to the shaded area in FIG. 2E.

【The invention's effect】

According to the present invention, when a gas leaks in a plant, when at least one of a plurality of gas detectors installed detects a gas having a concentration equal to or higher than a predetermined value, the location of the gas leak is immediately detected. Can be estimated. Therefore, it is possible to find a gas leak location more quickly than before and take countermeasures, improve the safety of the plant, and contribute to the prevention of pollution.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of a system for demonstrating a method for estimating a gas leakage location according to the present invention. FIG. 2 is a diagram for explaining steps when estimating a gas leakage location by the method of the present invention. FIG. 3 is a view showing the wind direction, its average swing width, and the gas diffusion width. 1A, 1B, 1C,… 1M,…, 1Y, 1Z: Gas detector 2: Anemometer 3A, 3B, 3C,… 3M, 3N: A / D converter 4: Data collection device 5: Central processing unit 6 : Storage device 7: Keyboard 8: CRT display device 9: Printer

Claims (1)

(57) [Claims] 1. A method for estimating a leak location when a gas leak occurs in a plant using a plurality of gas detectors installed in the plant, comprising the following steps. Method: a) Wind direction and wind speed data is continuously collected and recorded, and b) When the leaking and diffusing gas is detected by at least one gas detector, the above wind direction and wind speed data is used. And calculate the average fluctuation of the wind direction within a fixed time that traces back the time when the gas was detected, and also calculate the diffusion width of the gas that is diffusing, c) The wind direction around the wind direction at the time of detection the average amplitude and the diffusion width of the gas added, pull the two straight lines representing the angle around the gas detector detects the leakage, to define the upwind direction of a region B _1, d) leak Have been installed around the knowledge gas detectors, among other gas detector that has not detected the gas at the time when said at least one gas detector detects a gas, which is in the region B ₁ With respect to the above, the area B ₂ formed by two straight lines having the same angle in the upwind direction is defined, and e) the area B ₁ is removed from the area B ₂ and the remaining area B ₃ is formed. Find the area B ₄ that overlaps the area A where the equipment that handles the gas to be detected is located.