JPH0797062B2 - Gas leak area estimation device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a technique for estimating a gas leakage region based on signals from a plurality of gas detectors.

(Prior Art) For example, in a chemical plant in which a large number of gas sources are scattered over a wide area, a plurality of gas detectors are arranged at important points to detect the three highest gas concentration signals at the time of gas leakage. , A method of estimating a gas leakage region by proportional calculation based on each detected concentration and the position where the gas detector is arranged has been proposed.

Although it is obvious that the position of the gas leakage region can be theoretically calculated by this method, the gas detector is usually used in an extremely wide area such as a chemical plant.
It is also a problem that it is impossible to accurately detect the leak area due to the influence of complicated air flow because it is arranged at intervals of m or more and various large equipment are scattered. Since the leakage area can be estimated only after the gas is detected by at least three gas detectors, the estimation can be performed after a certain time has elapsed from the occurrence of the leakage, and the initial response is delayed. There are problems and a large amount of gas leakage is required.

(Purpose) The present invention has been made in view of such a problem, and its object is a gas capable of estimating a gas leakage region in a wide area as quickly as possible regardless of the wind direction and the wind speed. It is to provide a leakage area detection device.

(Summary of the invention) That is, the feature of the present invention is that the first storage means for storing coordinate data of a plurality of gas detectors arranged in the plant and the gas in a windless state are sequentially updated. For a period longer than that required to reach each of the gas detectors, wind direction data from the wind direction and wind speed measuring means in the plant, and wind direction for storing wind speed data, and second storage means for storing wind speed history, When at least one of the gas detectors detects a concentration equal to or higher than a reference concentration, the coordinate data is stored in the first storage unit, and the wind direction data is stored in the second storage unit for storing the wind direction and the wind speed history. A means for reading the wind speed data and calculating the leakage area is also provided, and in consideration of the gas flow caused by the time difference between the occurrence of the gas leakage and the detection thereof, only the signal from the first detector is used. This is the point where it is possible to estimate the leakage area.

(Examples) Therefore, the details of the present invention will be described below based on illustrated examples.

FIG. 1 shows an embodiment of the present invention. In the figure, reference numeral 1 is a gas leakage area detecting device characterized by the present invention, and is a site of a plant P in which various facilities are arranged on the site. And a signal from a plurality of gas detectors S1, S2, S3, ..., which are arranged in a plane and are provided with a ground clearance corresponding to the specific gravity of the gas detected through the scanner 2, and an anemometer. The signal from K is input, and the leak area and the leak amount are output to the display 3.

Reference numeral 11 in the figure is a wind direction and wind speed history storage circuit that stores the average wind direction and the average wind speed for a certain period of time, for example, 10 seconds, and diffuses at least from the leak region to the gas detector S in a windless state as shown in FIG. The longest time required to do so, that is, the storage capacity for the time required for the gas to diffuse from the diagonal intersection of three or four gas detectors that surround one point to the farthest gas detector, and to update the stored data However, the wind direction and the wind speed are stored together with the time tn, and the stored contents are output according to a command from the arithmetic unit 14 described later. Reference numeral 12 denotes a wind direction / speed correction circuit, which is a reference direction as shown in FIG. 3, for example, the wind direction about the vicinity where the gas detectors S1, S2, S3 ... Stores the data obtained by investigating wind speed and
It is configured to output based on a command from.
Reference numeral 13 is a coordinate data storage circuit for each gas detector S1, S2, S3.
Coordinate data (X1, Y1) (X2, Y2) where Sn is located
(X3, Y3) ... (Xn, Yn) and, if necessary, the layout of the plant equipment are stored. Reference numeral 14 denotes the above-described arithmetic unit, which is composed of a microcomputer having a CPU 14a, a ROM 14b, and a RAM 14c, and has a gas concentration signal from each gas detector S1, S2, S3, ... Based on a signal from the correction circuit 12, the gas leak region estimation calculation and the leak amount calculation calculation are performed based on a flowchart described later. Reference numeral 15 denotes an external storage device such as a magnetic disk device, which is used for each gas detector S1, S2, S3.
.., and the signals from the wind direction and wind speed history circuit 11, the wind direction and wind speed correction circuit 12, and the wind direction and anemometer K, and the estimation calculation process are recorded.

Next, the operation of the apparatus configured as described above will be described based on the flowchart shown in FIG.

When the apparatus is activated, the average data of the signals from the wind anemometer K is stored in the wind direction and wind speed history storage circuit 11 along with the elapsed time, and at the same time, the data after a certain time has passed are sequentially updated to the latest data.

When gas leaks from a certain facility in such a state, the leaked gas is scattered while being affected by the surrounding air flow.

[When the influence of wind is greater than the diffusion rate of gas] The gas leaked from the equipment is
When reaching the second gas detector Sa, the gas detector Sa outputs a signal proportional to the gas concentration. This allows the computing device
14 reads the coordinate data (Xa, Ya) of the first gas detector Sa from the detector coordinate data storage circuit 12 that has output the signal, and at the same time, based on the data of the wind direction anemometer K and the wind direction wind speed history storage circuit 11. To determine if there is a wind effect.

In this case, since the influence of the wind cannot be ignored, the wind direction wind speed history storage circuit 11 is accessed, and the past wind direction wind speed data stored here is read so as to be sequentially traced back. If the location of the gas detector Sa that has output the signal at this time (Fig. 5) is located at a location where the airflow is disturbed by the influence of equipment, etc., the wind direction and wind speed history is stored. The signal from the circuit 11 is corrected by the correction circuit 12 and the path P ₁ of the air flow from the time when the leakage occurs to the gas detector Sa,
Calculate P ₂ , P ₃ . Coordinates (Xb, Yb) of gas detectors Sb, Sc, Sd positioned so as to surround this path P ₁ , P ₂ , P ₃
(Xc, Yc) (Xd, Yd) is read from the coordinate data storage circuit 13, a circle M having this coordinate on the circumference is calculated, and displayed on the display 3 as a leak area. As a result, the second and third
The operator will be promptly notified of the leakage area without waiting for the gas detection signal from the gas detector. First
The leakage area can be estimated with much higher accuracy than the estimation area based only on the wind when the signal is output from the th gas detector.

When the diffusion region of the leaked gas expands with the passage of time and a signal is output from the second gas detector, the route of the air flow up to the detection time is calculated based on the process in the same manner as described above, and this route is calculated. , The gas detector that first detected the gas
The leakage area estimation calculation is performed while taking into account the Sa coordinates (Xa, Ya).

That is, the leaked gas mass spreads over time due to diffusion, and the area to be taken into the orientation becomes large, which makes the estimation of the leak region inaccurate. While respecting the first estimation result based on the Sa coordinates (Xa, Ya) as a reference, the estimation calculation is performed using the detection results of the second, third, ... Detectors S, Sc. To execute.

[When the influence of wind can be ignored] When the gas leaked from the equipment diffuses and reaches the first gas detector Sa, the gas detector Sa outputs a signal proportional to the gas concentration. As a result, the arithmetic unit 14 reads the coordinates (Xa, Ya) of the detector Sa that has output the signal from the coordinate data storage circuit 12, and at the same time determines whether or not there is the influence of the wind based on the signal from the anemometer K. .

In this case, since the wind speed signal from the wind direction anemometer is extremely small, it is determined that there is no effect of the wind, and then the past data is read from the wind direction wind speed history storage circuit for confirmation, and the history of wind influence is recorded. Judge about. As a result, when the influence of the wind can be ignored, the gas diffuses in all directions centering on the leakage region L, so that the gas detector Sa closest to the leakage region L is
(Fig. 6). The arithmetic unit 14 uses this detector S as the center of the coordinate (Xa, Ya) of the gas detector that has output the signal.
4 gas detectors Sb, Sc located so as to surround a,
Select Sd, Se and their coordinates (Xb, Yb) (Xc, Yc) ... (X
e, Ye) is read. Then, an area M passing through a substantially midpoint between the detector Sa that has detected the gas and the other detectors Sb, Sc, ... Se is calculated, and this area is displayed on the display 3 as a leakage area. As a result, the leak region is displayed without waiting for signals from the second and third gas detectors.

If the leaked gas diffuses with the passage of time and outputs detection signals to other gas detectors in sequence, the coordinates of the gas detector that outputs the highest concentration signal are read out. A region centered on the coordinate and passing through the midpoints of other detectors in the immediate vicinity is displayed.

In this way, by estimating the leakage region with the wind velocity set to zero, an error due to irregularity of the wind direction, which tends to occur particularly in a weak wind, is eliminated, and a high angle estimation can be performed.

In parallel with these estimation calculations, the calculation unit 14 outputs the data such as the wind direction, the wind speed, the detector coordinates, and the calculation process, which are the basis of the calculations, and stores the data in the external storage unit 15.

[Calculation of Leakage Amount] In the process of estimating the leakage region through the above-mentioned process, when the leakage progresses and the gas reaches a plurality of detectors, the average concentration gradient is calculated based on the gas concentration signal,
Areas Z1 and Z2 are calculated and displayed at a constant concentration level, for example, in increments of 100 ppm (Fig. 7), and at a certain constant concentration, for example,
It is possible to estimate the amount of leakage per unit time by calculating the area of the area surrounded by the 100 ppm isoconcentration line.

[Experimental example] By the way, in order to simplify the calculation of the leakage amount, the applicant of the present invention arranged a plurality of gas detectors at intervals in the field, and under a certain condition, for example, a wind speed of about 1.5 M / sec or less. Area that is surrounded by 100ppm isoconcentration curve in this state, releasing 100 / min of gas in the state
Calculate S ₀ (m ² ).

Next, while changing the gas outflow rate (/ minute) and the wind speed,
The leakage amount in each state was estimated by calculating the area S surrounded by the 0 ppm isoconcentration curve and the leakage amount as Q = S / S ₀ × 100 (/ min), and the results shown in Table 1 were obtained. .

By the way, when the wind velocity increases, the gas air peripheral portion is easily blown away by the wind, and as is apparent from Table 1, it is estimated to be small. Therefore, the wind speed V
When the correlation between (m / sec) and the actual amount of leakage was calculated, Q = S / S ₀ × 100 × (V + 1) (/ min) (1) Even when affected by wind It has become possible to estimate the amount of leakage within the range of 1/2 to 2 times.

When all the work is completed in this way, the data stored in the external storage device is analyzed, the cause of the actual deviation of the leakage area is investigated, and the operation program is corrected to The estimation can be performed more accurately.

In this embodiment, the leak amount per unit time and the cumulative leak amount are calculated with the leak estimation region as the central point, but the leak region and coordinates confirmed by the field survey are input from the keyboard or the like. The leak amount may be calculated with the determined leak region as the center.

Further, in this embodiment, the wind direction and the wind speed at each point are corrected, but in the case where the turbulence of the air flow due to the equipment can be ignored or the arrangement interval of the detectors is small, it can be omitted practically. It is clear that the leakage area can be estimated with sufficient accuracy.

Further, in the above-described embodiment, four gas detectors forming a rectangle are specified, but three gas detectors forming a triangle may be specified depending on the arrangement of the gas detectors. It is clear that also has the same effect.

FIG. 8 shows a second embodiment of the present invention, in which probability data storing the probability of leakage of each facility installed in the plant, such as tanks, valves, pumps, joining members, etc. The signal from the memory circuit 20 is input to the arithmetic unit 14, and according to this embodiment, when the leakage region is calculated by the same process as described above, the region estimated based on only the gas concentration is calculated. The reliability is verified on the basis of the data from the probability data storage circuit 20, and the operator's attention is also given to equipment with a high probability although it deviates from the estimated position to enable a higher estimation. That is, when the leakage probability at the estimation point is low, the equipment with the highest probability and the position thereof are selected from the equipment adjacent to this, and a more probable area is displayed.

FIG. 9 shows a third embodiment of the present invention. In the figure, reference numeral 21 is a wind direction data averaging circuit, which indicates the instantaneous wind direction data D (t) output from the wind direction anemometer K. An average calculation is performed based on a time T (V) that is inversely proportional to V, and this average value D (t) / T (V) is output to the wind direction wind speed history storage circuit 11 together with the wind speed V. ing.

According to this embodiment, it is possible not only to eliminate the error caused by the uncertainty of the wind direction data of the anemometer, which tends to occur particularly in a breeze, but to improve the reliability of the leakage area estimation calculation, and also to consider it. The wind direction data to be obtained can be obtained with the accuracy required for the estimation calculation, and the estimation time can be shortened by eliminating unnecessary calculation steps.

(Effects of the Invention) As described above, according to the present invention, the first data storing coordinate data of a plurality of gas detectors arranged in a plant is stored.
Of the wind direction data from the wind direction and wind speed measuring means in the plant for a period longer than that required for the gas to reach each gas detector in a windless state, while being sequentially updated.
And the wind direction for storing wind speed data, second for storing wind speed history
When the at least one of the storage means and the gas detector detects a concentration equal to or higher than the reference concentration, the coordinate data from the first storage means and the wind direction data from the second storage means for storing the wind direction and the wind speed history, And a means for calculating the leakage region by reading the wind speed data, and the gas flow caused by the time difference between the time when the gas leaks and the time when the gas leak is detected is corrected and estimated. Not only can the leak area be displayed promptly without waiting for the output of the signal from the third gas detector, but the leak area can be displayed at a high angle regardless of weather conditions, terrain, or equipment layout. Can be estimated.

Further, in the present invention, since the above-mentioned configuration is provided with means for calculating the gas leakage amount based on the concentration signal from each gas detector, it is necessary to accurately calculate the gas leakage amount and take appropriate accident countermeasures. Can be done.

[Brief description of drawings]

FIG. 1 is a block diagram of an apparatus showing an embodiment of the present invention, FIG.
FIG. 3 is a schematic diagram showing the configuration of a dictionary used in the same apparatus, FIGS. 4, 5, 6, and 7 are flowcharts and explanatory diagrams showing the operation of the same apparatus, and FIGS. It is a block diagram showing an example of. P ... Plant S1, S2, S3 ... Gas detector K ... Wind direction anemometer

Claims (4)

[Claims] 1. A first storage means for storing coordinate data of a plurality of gas detectors arranged in a plant, and a gas required to reach each of the gas detectors in a windless state while being sequentially updated. At least one of the wind direction data from the wind direction and wind speed measuring means in the plant and the second storage means for storing the wind speed and wind speed data, and the wind speed history for a longer period, and at least one of the gas detectors has a reference concentration or more. When the density of is detected, the coordinate data from the first storage means,
Further, the gas leakage area estimation device is provided with means for reading the wind direction data and the wind speed data from the second storage means for storing the wind direction and the wind speed history and calculating the leakage area. 2. A first storage means for storing coordinate data of a plurality of gas detectors arranged in a plant, and it is necessary for the gas to reach each of the gas detectors in a windless state while being sequentially updated. At least one of the wind direction data from the wind direction and wind speed measuring means in the plant for a longer period, and the wind direction and wind speed data storing second storage means for storing wind speed history, and at least one of the gas detectors having a reference concentration or more. Means for calculating the leakage area by reading the coordinate data from the first storage means and the wind direction data and the wind speed data from the second storage means for storing the wind direction and the wind speed history when the concentration is detected. A gas leakage region estimation apparatus comprising: a unit that calculates the amount of leakage based on a concentration signal from each of the gas detectors; and a unit that corrects the calculated amount of leakage according to the wind direction. 3. The wind direction wind speed measurement is dependent on a first storage means for storing coordinate data of a plurality of gas detectors arranged in the plant, and the wind direction wind speed depending on the wind speed measured by the wind direction wind speed measurement means in the plant. The wind direction data from the means is averaged, and the wind direction sampling means that makes the value of the time variable, and the sampling means for a period longer than that when the gas reaches each of the gas detectors in a windless state while being sequentially updated. A second storage means for storing wind direction and wind speed data from the wind direction and wind speed measurement means, and at least one of the gas detectors detects a gas having a reference concentration or more. , A method for calculating the leakage area by reading the coordinate data from the first storage means and the wind direction data and the wind speed data from the second storage means for storing the wind direction and wind speed history. Gas leakage area estimation device including a. 4. An arrangement coordinate of each facility in a plant, and a third storage means for storing data of a probability of occurrence of leakage of the facility, wherein the calculated leakage area can be verified. The gas leakage area estimation apparatus according to 1 of 2 and 3.