JPH0783786A - Estimation of leak spot and leak quantity of gas - Google Patents

Abstract

PURPOSE:To estimate the leak spot and quantity of gas by calculating the gas flux of leaked gas proportional to the leak quantity of gas from wind direction and velocity data and leaked gas concn. data. CONSTITUTION:A gas concn. data collecting and storing device 1 and a wind direction and velocity data collecting and storing device 2 input the measured data of (M) gas detectors G and (N) aerovanes B (M>=2, N>=1, M>N>M/20) to collect and store those data while renew them. A data processor 3 multiplies the gas concn. data and wind direction and velocity data from the devices 1, 2 to calculate gas flux and a CRT display device 8 sets the magnitude of the gas flux to a length vector and a wind direction to a direction vector to display the gas flux. Two selected gas detectors are extended so as to permit the correction vectors to pass to calculate lines and the crossing point of those lines is calculated. When the leak quantities of gas operated by the processor 3 coincide with each other, the crossing point is judged to be a real gas leak spot and the gas leak quantity at the leak spot.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for estimating a gas leak point and a gas leak amount in a gas leak from gas concentration data from a gas detector and wind direction and wind speed data from an anemometer, and mainly relates to flammability. The present invention relates to a method for estimating a gas leak point and a leak amount useful for early coping with gas leaks in various outdoor plants that may leak gas such as gas, toxic gas, various oils, and vapors of organic solvents.

[0002]

2. Description of the Related Art Conventionally, a gas leakage point in gas leakage is a method of estimating the gas leakage point from the concentration gradient based on the gas concentration data of the leakage gas from at least three gas detectors. No. 155932) has been industrialized, but there is a problem that it takes a considerable time for the gas to be detected by three or more gas detectors arranged by a normal method.

Further, when the leak gas is detected by the gas detector, if the influence of the wind is large, the gas leakage region is estimated from the past history of the wind direction wind speed data, and if the influence of the wind can be ignored, the gas is detected. A method in which the inside of a circle passing through the vicinity of the midpoint between the gas detector where the leaked gas is detected and the leak gas is detected as simply spreading the leak in four directions (Japanese Patent Laid-Open No. 1-219533) (Gazette) is also proposed. In this case, the amount of gas leakage is estimated based on the empirical correlation formula between the area surrounded by the isoconcentration lines and the wind speed. There is a problem that the error becomes large when the gas leakage region is estimated from the history of wind direction and wind speed data in the past.

Furthermore, when the leak gas is detected by the gas detector and the wind speed exceeds a certain limit, the amplitude of the wind direction is set to the diffusion width based on the average value of the wind direction wind speed data in the past certain time. Two straight lines having the added angle are drawn on the windward side centering on the gas detector to obtain a leakage candidate area, and the same 2
A straight line is drawn for gas detectors that do not detect leaked gas, and the gas handling area that excludes this part from the leak candidate area is the estimated gas leak area.If the wind speed is below a certain limit, leak gas is detected. There is also proposed a method (Japanese Patent Laid-Open No. 2-47527) in which a gas handling region inside a rectangle passing through the vicinity of an intermediate point between adjacent gas detectors centering on another gas detector is used as a gas leakage region. There is a problem that the leakage region estimated by such a spatially wide estimation method is too wide.

In addition, when the leak gas is detected by the two gas detectors, the correlation equation between the leak gas concentration and the distance is 2
By substituting the leaked gas concentration for each gas, find the distance from the horizontal line that passes through the gas leak source candidate and orthogonal to the average wind direction to each gas detector, and perform the same calculation when the average wind direction changes to obtain a new distance. , A method of estimating the gas leakage amount from a similar correlation formula regarding the gas leakage amount, where the estimated gas leakage location is near the intersection of horizontal lines orthogonal to the average wind direction passing through the gas leakage source candidates corresponding to these two distances ( Japanese Patent Laid-Open No. 2-190734) has also been proposed, but the wind direction and wind speed data in the vicinity of the gas detectors or at distant positions not in the same place are applied to two gas detectors, and the time series of the data is obtained. There is a problem that it takes too much time to proceed with the estimation calculation of the gas leakage region from only the instantaneous data at each time point without taking into consideration the change in the situation.

On the other hand, although the sensitivity of the gas detector has been improved in recent years, when the alarm gas concentration set value is lowered, the gas generated in the maintenance work of a distant plant, the gas generated by the evaporation of the solvent during coating, and the tank are generated. Since the mode of the leaking gas generation source such as combustible vapor cannot be discriminated, an alarm sounds unnecessarily and the high-sensitivity gas detector cannot be used.

On the other hand, the gas concentration of the leaked gas is not proportional to the leaked gas amount except when the wind speed is constant, as can be seen from the well-known Sakagami equation and Sutton's equation which express the diffusion of gas. . That is, even if the gas concentration is low, there is a problem if the wind speed is high. Therefore, it is desirable to judge the gas leakage by the gas flux obtained by multiplying the wind speed and the gas concentration.

In the following explanation, Sutton's formula (issued in August 1981) is used as a formula for expressing the relation between the concentration of leaked gas due to diffusion of leaked gas and the parameters determined by wind speed, gas leak amount, positional relationship and meteorological conditions. "Ministry of Pollution Control Technology and Regulations (Atmosphere)"
Based on the 4th edition). Needless to say, instead of Sutton's formula, Sakagami's formula or other logical formula, empirical formula, etc. may be used.

From the Sutton equation, if the diffusion parameter determined by the wind direction and the weather conditions is constant and the amount of leaked gas per unit time is constant, the gas flux becomes constant. The Sutton equation is usually solved for the gas concentration, but it is deformed to express the gas flux.

[0010]

[Equation 1]

Here, when there is no horizontal obstacle such as a pedestal that prevents vertical diffusion in the upper space from the gas leak point to the gas detector,

[0012]

[Equation 2]

When there is a horizontal obstacle such as a pedestal that prevents vertical diffusion in the upper space from the gas leak point to the gas detector, the leaked gas is repeatedly reflected by the upper and lower horizontal obstacles (including the ground). If there is

[0014]

[Equation 3] Becomes

The symbols included in the above equation will be described in consideration of the plant. F (x, y, z): The coordinates of the gas leak point are (0, 0, H)
And the value of the gas flux at any position coordinate (x, y, z) when the x axis is taken in the direction of the wind. C (x, y, z): The coordinates of the gas leak point are (0, 0, H)
And the gas concentration at any position coordinates (x, y, z) when the x axis is taken in the direction of the wind. Q (0,0, H): Leakage gas amount per unit time. U: Wind speed. H: It is the height from the ground surface of the leak point, but if there is a floor such as a pedestal, it is the height from the floor surface. z is also an arbitrary height from the same floor. T: The distance between the upper and lower horizontal obstacles (including the ground) when there is a horizontal obstacle such as a gantry that prevents vertical diffusion in the upper space from the gas leak point to the gas detector. m: the number of reflections. Usually, if m = -2 to 2, a sufficiently good approximation is obtained. C _y , C _z , n: Sutton's diffusion parameters determined by H and meteorological conditions. When there are horizontal obstacles (including the ground) at the top and bottom, it is considered that they form a neutral layer because the temperature gradient of the atmosphere between them is small. n takes a numerical value of 1/5 to 1/2,
It is 1/4 in the neutral layer. Further, in the case of a neutral layer having a height of 10 m or less, C _y = 0.21 (m ^1/8 ), C _z = 0.12
(M ^1/8 ).

As can be seen from the above equation regarding the estimation of the leak point, when the leak gas amount per unit time is constant,
If the wind is blowing just below the leak point of the gas detector (when y = 0 in the above equation), the value of gas flux becomes maximum, so the value of gas flux becomes maximum. The opposite direction of the wind direction indicates the direction of the leak point.

Normally, the amount of leaked gas does not change drastically with time, but the wind direction and speed change with time, so the magnitude and direction of the gas flux changes correspondingly. If the maximum value in the time series of the value of the gas flux in the past fixed time, for example, the past one hour, and its direction are updated and obtained as a vector, the gas leakage source in the direction opposite to the wind direction of this maximum value can be known. Utilizing this fact, the inventor extends the wind direction of the maximum value in time series of the gas flux values of at least two points in a certain area so as to pass through the gas detector, and obtains their intersection. A patent application has been filed for a method of estimating the area surrounding the point as the position of the gas leakage source.

However, even if the wind direction changes with time, it may not just blow from the direction of the gas leakage source.
This means that the gas leakage source does not always exist in the direction opposite to the direction of the maximum value of the gas flux value on the time series.

[0019]

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the prior art as described above, and the leakage amount from the wind direction wind speed data from the wind direction anemometer and the leakage gas concentration data of each gas detector. Gas flux of leaked gas proportional to (leakage gas concentration x wind speed: amount of leaked gas flowing per unit time, unit area. Gas flux has a direction of wind, and leak gas concentration x wind speed value is a scalar It is a vector to be calculated.), And it is intended to provide a method of estimating the gas leakage point and the gas leakage amount by making the best use of this.

[0020]

SUMMARY OF THE INVENTION According to the present invention, the above-mentioned problems can be obtained from gas concentration data from a plurality of gas detectors in a certain area and from an anemometer installed near the gas detectors. A method for estimating a gas leakage point and a gas leakage amount from wind direction and wind speed data, which is obtained by multiplying the gas concentration data and the wind speed data to obtain a gas flux value for each of the gas detectors, and determining a past predetermined value. A vector having the maximum value of the gas flux in time as the magnitude and the wind direction at that time as the direction is updated for each gas detector, and two specific gas detectors having the vector are selected. Then, a line obtained by extending each of the vectors corresponding to each of the selected gas detectors through the gas detector and its intersection are obtained, and the intersection is a gas leak point, and each selected gas Assuming that the detector is just downwind of the gas leak point, the parameters determined by the gas concentration, wind speed and weather conditions in the gas detector, and the positional relationship between the gas leak point and the gas detector, Each of the estimated values of the gas leakage amount obtained from the gas diffusion formula expressing the relationship between the parameter and the positional relationship is obtained, and when the estimated values of the respective gas leakage amounts match each other, the intersection is determined to be true. If it is determined that the gas leak point and the estimated values of the gas leak amounts do not match each other, the specific gas detector corresponding to the larger one of the estimated values of the gas leak amounts is connected to the intersection point. Assuming that there is a true gas leak point on the line, and assuming that the point is a gas leak point at each point on the line, an estimated value of the gas leak amount corresponding to each of the selected gas detectors is obtained and selected. Corresponding gas leaks for each gas detector A method of estimating a gas leak point and a leak amount, which is characterized in that a point at which the estimated values of the amounts coincide with each other is determined to be a true gas leak point, or the intersection point is determined by determining that there is a gas leak point near the intersection point. Parameters determined by the gas concentration, wind speed and meteorological conditions in each gas detector selected in the vicinity, the positional relationship between the gas leak point and the gas detector, and between the parameter and the positional relationship. A curve that agrees with the estimated value of each gas leakage amount obtained from the gas diffusion formula expressing the relationship is obtained, and the vector updated or stored after a predetermined time has passed in each of the selected gas detectors. In the same manner as above, the curves that match the estimated values of each gas leak amount are obtained from the vector whose magnitude is the past vector or present gas flux value and whose current wind direction is the direction. This is achieved by providing a method for estimating a gas leak point and a leak amount, which is characterized in that the intersection of the curves is determined as a true gas leak point. In particular, when there are two curves each obtained at the beginning and two after the predetermined time has passed and there are two intersections, the vector updated after the predetermined time has passed or the stored past From the vector having the vector or the current gas flux value as the magnitude and the current wind direction as the direction, a curve in which the estimated values of the respective gas leakage amounts coincide with each other is obtained in the same manner as described above, and the first-obtained curve, 2 It is advisable to determine the intersection point on the side where the curve obtained at the third time and the curve obtained at the third time intersect together as the true gas leakage point.

[0021]

First, when the equation (1) is transformed into a solution for Q,

[0022]

[Equation 4] Becomes

Here, with respect to the i-th gas detector, the leak gas concentration is C _i , the wind speed is U _i , the i-th gas detector with respect to a horizontal straight line that passes through the gas leak point and is orthogonal to the wind direction. Cross a straight line parallel to the wind direction passing through, passing through the distance from the gas detector to the intersection, that is, the gas leak point,
The distance from the gas detector to the horizontal straight line orthogonal to the wind direction is L _i , the distance from the intersection to the gas leak point is W _i , and the height from the floor is Z _i . At this time, equation (4) is used. The gas leakage amount obtained by the above is set as Q _i .

For the gas detector at the position shown by point P ₁ as shown in FIG. 1, an extension line parallel to the wind direction passing through the corresponding gas detector at the time series maximum value of the gas flux value is drawn. When the intersection point R ₁ is obtained, assuming that the point R ₁ is a gas leakage point, the diffusion parameter for the point P ₁ is C _y ,
C _z , n, leakage gas concentration C ₁ , wind speed U ₁ , distance L ₁ , distance W
Substituting ₁ (= 0) and height Z ₁ into the above equation to calculate the value Q ₁ ,
Similarly, the value Q ₂ is calculated for the gas detector located at the point P ₂ . In this case, the average height of the two gas detectors is approximately the height H of the gas leak point.

Further, if the gas flux is measured at several points in the height direction and the height Z _m giving the maximum value in the height direction and the distance X _m parallel to the wind direction can be obtained, It is possible to accurately calculate the height H of the gas leak point.

That is, when the height which gives the maximum value of the value of the gas flux in the height direction from the expressions (1) and (2) is Z _m ,

[0027]

[Equation 5]

[0028]

[Equation 6]

Is obtained. Therefore, H can be obtained by substituting Z _m and X _m into the two equations (5) and (6) and solving them by a trial method or the like. Further, the equations (1) and (3) can be similarly solved.

[0030] Thus Q _1, Q ₂ which is calculated is, if Q ₁ = Q ₂ if the point R ₁ represents a gas leakage point, Q ₁ = Q ₂
Q, which indicates, indicates the amount of gas leakage. In this case point P ₁
This means that the wind direction has changed so that P ₂ is just leeward of the gas leakage point.

On the other hand, when Q ₁ ≠ Q ₂ and Q ₁ > Q ₂ , find a gas leakage point where Q ₁ = Q ₂ between the point P ₁ and the intersection point R ₁ as follows. You can

First, since Q _i decreases as L _i decreases from the equation (4), a distance L ₁₁ smaller than the distance L ₁ between the points R ₁ and P ₁ is provided as shown in FIG. the point R ₂ are smaller Q ₁ than Q ₁ previously calculated by calculating the Q ₁ assuming gas leakage point is obtained.

Assuming that the point R ₂ is a gas leakage point,
As shown in FIG. 1, through the point R _2, and as a horizontal straight line parallel to the wind direction at the maximum value when the series of the gas flux at the point P _2, the point R _2, and perpendicular to the wind direction by crossing the horizontal straight line, the intersection distance L ₂₁ from the point P ₂ to R ₂₁ is obtained, further the distance W ₂₁ from the intersection point R ₂₁ to the point R ₂ are obtained. By substituting these L ₂₁ and W ₂₁ into the above equation and calculating Q ₂ , exp (W ₂₁ ² / C _y ² L
_i ^2-n) is larger Q ₂ from Q ₂ to which the previously calculated so exponentially increase obtained with W ₂₁ Q ₁ = Q ₂ to become such points R ₂
Can be found. In addition, in the same manner as above, FIG.
Q ₁ to at point a line obtained by extending the line connecting the R ₁ and the point P ₁ to the
Another point R ₃ (not shown) can be found such that = Q ₂ .

By performing the above-mentioned work a plurality of times on the added data, gas leak point candidates are concentrated on one side of these two points R ₂ and R ₃ . Such a point indicates a gas leakage point, and Q where Q ₁ = Q ₂ indicates a gas leakage amount. Here, if Q ₁ <Q ₂ , then the above point P ₂
And point P ₁ should be exchanged.

If the gas leak point and the gas leak amount are known, the leak gas concentration distribution or the like can be calculated for an arbitrary wind direction and wind speed, which can be used as a safety measure. Also, in the above case, when the weather condition is unknown, the gas leak point and the gas leak amount may be obtained by changing the Sutton diffusion parameter using the weather condition as a parameter.

In an actual plant, there is turbulence in the air flow due to equipment and the like, which deviates from the gas diffusion in the ideal state as shown here, but first, the gas leak point and the gas leak amount in the ideal state are estimated. Then, by correcting this deviation, for example, assuming a streamline around the device, it is possible to approximate the actual state.

In the method of estimating the gas leakage point and the leakage amount of the present invention, when the gas concentration data and the wind speed data are within the measurable lower limit values or more, the gas concentration and the wind speed are multiplied to determine the gas flux. Calculate the value and if either is below the measurable lower limit, formally calculate and display the value of the gas flux using each measurable lower limit, but the following gas leakage points and gas leakage amounts are estimated. It's good not to.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described in detail with reference to FIGS.

An example of a system for realizing the method for estimating the gas leak point and the leak amount according to the present invention is, as shown in FIG.
2) Gas detectors G (1) to G (M) and N (≧ 1)
Gas concentration data and wind direction and wind speed data are stored in the gas concentration data collection and storage device 1 and the wind direction and wind speed data collection and storage device 2 which are connected to the data processing device 3 and each of which has an individual wind direction anemometer B (1) to B (N). To enter.

Further, the data processing device 3 is provided with a keyboard 4 for inputting gas flux alarm set values, position data of a gas detector and anemometer and various operations, and gas detectors G (1) to G (G). (M) and anemometer B (1)-
B (N) number and instrument position storage device 5 for storing the position, gas flux for each gas detector number, gas concentration,
An external storage device 6, an alarm device 7, a CRT display device 8 and a printer 9, which store the wind direction, the wind speed, etc., in a time series for the past fixed time, for example, the past one hour at required time intervals, are connected.

Wind direction anemometers B (1) to B (1) to B (1) to B (B) located near the gas detectors G (1) to G (M) are provided as approximate wind velocity anemometers at the respective positions.
(N) is selected so that the gas concentration data from each gas detector and the wind direction wind speed data have a one-to-one correspondence.

In this case, a plurality of wind direction anemometers may be selected for one gas detector and the wind direction wind speed data may be interpolated or extrapolated depending on the positional relationship. Usually N is M
1/20 or more, preferably 1/10 or more and not exceeding M.

Further, the gas detector and the wind direction anemometer may be integrated so that the wind direction, the wind speed and the gas concentration of the air at the same place can be measured at the same time.
Becomes M = N.

In this system, the measurement data of the gas detector and the anemometer that are constantly transmitted are converted into digital signals, and the data processor 3 selects and stores the data.
It is designed to be used for calculations. Further, since the wind direction and wind speed change quickly with time, if the response characteristics of the wind direction and anemometer are too good, it is possible to use, for example, the average value of the wind direction and wind speed for 3 seconds as the wind direction and wind speed data, if necessary. It has become.

The gas concentration data collection / storage device 1 collects the gas concentration data from the gas detector in time series at regular time intervals while updating the past data. Similarly, the wind direction / wind speed data collection / storage device 2 collects and stores the wind direction data and wind speed data from the wind anemometer while updating them.

The data processing device 3 retrieves the gas concentration data from the gas concentration data collecting and storing device 1 and retrieves the wind direction and wind speed data corresponding to each gas detector from the wind direction and wind velocity data collecting and storing device 2, and collects these gas concentrations. If the data and wind speed data are in the measurable range, they are multiplied to calculate the gas flux.If the wind speed data is lower than the measurable range, the gas velocity is multiplied by the lower limit measurable wind speed. Calculate the flux,
When the gas concentration data is lower than the measurable range, the gas concentration is calculated by multiplying the measurable lower limit gas concentration by the wind speed. Here, in general, the gas detector has a poorer response characteristic than the anemometer, so in order to adjust this, in this system, the detection response characteristic between each gas detector and the corresponding anemometer is used. The above processing is performed with the gas concentration data traced back by the time difference corresponding to the detection delay.

FIG. 3 is an example of a display screen of the CRT display device 8, showing a rectangular pedestal part which is a part of the plant, and the main equipment installed on the pedestal is shown by imaginary lines. . Further, each gas detector G (1) to G (1
2) are arranged in a matrix. In this example,
Gas detectors G (1), G (4), G (9), G at the four corners
(12) is an anemometer B (1), B (2), B (3),
It is integrated with B (4), and the wind direction wind speed of the gas detector is obtained by interpolating the wind direction wind speed data from the wind direction anemometers at the four corners. Here, in FIG. 3, the current value of the gas flux centered on a point corresponding to the position of each gas detector arranged in a matrix and its direction are displayed using the symbols shown in FIG. is there. That is, when the gas concentration data and wind direction wind speed data are in the measurable range,
The gas detector is the center point, the size of the gas flux is the length,
The gas flux is indicated by an arrow as a vector whose direction is the wind direction. Also, the current gas flux is displayed with a thin arrow, and this display is overlaid to display the maximum gas flux on the time series of the gas flux in the past certain time, for example, the past one hour, with a thick arrow. And these displays are constantly updated. On the other hand, the wind speed is within the measurable range, but when the gas concentration data is lower than the measurable range, the gas flux is calculated by multiplying the gas concentration at the lower limit of measurable value by the wind speed, and the size of the gas flux is taken as the radius. It is indicated by a circle and the wind direction is indicated by an arrow. Furthermore, when the wind speed is lower than the measurable range, the gas flux is calculated by multiplying the gas concentration by the measurable lower limit wind speed,
Only the circle whose radius is the size of the gas flux is shown.

When the gas flux exceeds the alarm set value, an alarm is issued unless the gas concentration is lower than the measurable range, and thereafter, the maximum value and its direction are displayed for the issued gas detector. Is changed to, for example, red and blinks.
Also, when only the gas concentration exceeds a certain value, an alarm is issued and the display for the corresponding gas detector is changed to, for example, orange and blinked, and the conventional alarm is also used.

On the other hand, in the CRT display device 8, arrows m and n are extended in the opposite direction to the intersection R of the gas detector whose gas concentration data and wind direction wind speed data are both measurable. (Lines o and p), the coordinate position of the intersection point R in the data processing device 3 can be calculated.

Next, in the data processor 3, the equations (1) to (6) shown in the operation are calculated to obtain the gas leakage point and the gas leakage amount Q, and the CRT display device 8 is used. The gas leak points are indicated by X and X'marks, and the gas leak amount Q and the gas leak position coordinates are displayed at the top of the screen.

Numerical examples are shown below. The area shown in FIG. 3 is a space sandwiched between a platform having a height of 4 m and a platform located at a position 3 m above it. The gas detector G (1) and the gas detector G
The distance to (2) is 20 m, and each is 0.5 m from the floor. That is, T = 3 (m), Z ₁ =
0.5 (m), Z ₂ = 0.5 (m), H = 0.5
(M), Cy = 0.21, Cz = 0.12, n = 1/4
Is. In addition, ethylene with a concentration of 100% leaked, and the maximum values F ₁ and F _{2 in} the time series of the gas flux values of the gas detectors G (1) and G (2) in the past hour were measured as follows. It is supposed to have been done. The direction of the gas flux is as shown in FIG. 3 or 1.

U ₁ = 2 (m / s) C ₁ = 200 × 10 ^-6 (m ³ / m ³ ) F ₁ = 400 × 10 ^-6 (m ³ / m ² s) U ₂ = 3 (m / S) C ₂ = 100 × 10 ⁻⁶ (m ³ / m ³ ) F ₂ = 300 × 10 ⁻⁶ (m ³ / m ² · s)

From the intersection of FIG. 3, L ₁ = 31.3 (m), L ₂
= 16.9 (m). Substituting these into the equation (4), Q ₁ = 7.1 × 10 ⁻³ (m ³ / s), Q ₂ = 2.
It becomes 1 × 10 ⁻³ (m ³ / s). Here, finding the two points to be Q ₁ ≠ Q ₂ since Q ₁ = Q _2.

L ₁₁ = 27.2 (m) W ₁₁ = 0 (m) L ₂₁ = 13.6 (m) W ₂₁ = 2.4 (m) Q ₁ = Q ₂ = 5.66 × 10 ^-3 (M ³ / s) or L ₁₂ = 36.9 (m) W ₁₂ = 0 (m) L ₂₂ = 21.5 (m) W ₂₂ = 3.2 (m) Q ₁ = Q ₂ = 8. 97 × 10 ^-3 (m ³ / s)

In FIG. 3, taking G (1) as the origin, G (4)
The position coordinates when the X axis is in the direction of and the Y axis is in the direction of G (9) are shown, and the leakage amount Q is shown in the unit of the flow rate per time.

This leak point is obtained when the gas detector G (1) is assumed to be just downwind, but the point that Q ₁ = Q ₂ is satisfied even if it is not downwind is the same as above. And the locus of this point is the leak point X, X ′.
In the above case, leakage estimation lines q and q'are also shown in FIG.

Further, when the maximum value of the gas flux value of the gas detector G (1) and / or the gas detector G (2) and its direction are updated after a certain period of time, for example, 30 seconds, the above is applied. A different Q from the curve obtained above in the same way
Leakage estimation lines q and q ′, which are loci of points where ₁ and Q ₂ coincide with each other, are determined, and an intersection of these leakage estimation lines is set as an estimated gas leakage point, and a gas leakage amount Q at the intersection is estimated. The amount of leakage.

If the maximum value of the gas flux and its direction are not updated after this fixed time,
Based on the current value of the gas flux value of the gas detector G (1) or the gas detector G (2) and its direction, or the stored past value of the gas flux and its direction,
In the same manner as above, another Q ₁ different from the curve obtained above,
Leakage estimation lines q and q ′, which are loci of points where Q ₂ coincides, are obtained, and the intersection of these leakage estimation lines is taken as the estimated gas leakage point, and the gas leakage amount Q at the intersection is estimated gas leakage amount. And

Numerical examples are shown below based on the example shown in FIG. Assuming that the maximum value of the gas flux value and its direction have not been updated after 30 seconds from the previous example, the current value of the gas flux of the gas detector G (1) is U ₁ = 2 (m / s) C ₁ = 150 × 10 ⁻⁶ (m ³ / m ³ ) F ₁ = 300 × 10 ⁻⁶ (m ³ / m ² · s), its direction (shown in FIG. 5) and gas detector G
Based on the maximum value of the gas flux value in (2) and its direction, a leakage estimation line was obtained by the same method as above, and q ₂
Indicated by. The leakage estimation lines q and q ′ in FIG. 3 are q ₁ and q ₁ in FIG.
It is shown by q ₁ ′.

The intersection X between q ₁ and q ₂ and the intersection X ′ between q ₁ ′ and q ₂ ′ are estimated gas leakage points, and the position coordinates of this point and the amount of gas leakage obtained from this position coordinate. Q is as shown in FIG.

Next, which of the above-mentioned two gas leak points X and X'is the true gas leak point can be determined by another data. Numerical examples are shown below based on the example shown in FIG.

After 30 seconds from the previous example, the gas flux
The maximum value and its orientation have not changed and have not been updated.
Then, the past data stored in the gas detector G (2) is stored.
The value of the gas flux, which is one of the₂= 1 (m / s) C₂= 100 × 10^-6(M³/ M³) F₂= 100 × 10^-6(M³/ M².S), its orientation (shown in FIG. 6) and gas detector G
Based on the maximum value of gas flux in (1) and its direction
Then, the leak estimation line is obtained by the same method as above,
q ₃, Q₃’ Leakage estimation line q in FIG.₁, Q₁'as well as
q₂, Q₂'Is the same as in FIG.

One of the intersections X and X ′ passes through q ₃ , and q ₁ , q ₂ and q ₃ intersect at one point, while the other intersection X ′ corresponds to q ₃ ′. Does not pass and is largely off. A point X where these three leakage estimation lines intersect one point is an estimated true gas leakage point, and the position coordinates of this point and the gas leakage amount Q obtained from this position coordinate are as shown in FIG. In the ideal case where the premise of the calculation is satisfied, there is only one true gas leak point, but in reality, the gas leak point increases with the passage of time due to fluctuations in the data, so the leak estimation lines q, q ' Is not displayed when the number of gas leak points is a certain number or more, for example, three or more, it is preferable to display only the gas leak point X in an overlapping manner and display the gas leak point coordinates and the average value of the gas leak amount.

The method shown in FIGS. 5 and 6 is a gas detector G.
Both (1) and the gas detector G (2) are methods for obtaining the gas leak point and the leak amount when the gas leak point is not just downwind, and are a more generalized method than the method shown in FIG. .

When the leakage estimation point obtained as described above is inside or near the pedestal of the plant, even if an alarm exceeding the gas flux alarm set value is not issued, an alarm is sounded with a different tone color, The display of the leakage estimation point is designed to blink.

When the leakage estimation point is located far from the pedestal of the plant, the gas generated by the maintenance work of the distant plant, the gas caused by the evaporation of the solvent at the time of coating, the flammable vapor generated from the tank, etc. are detected. Since it is possible to immediately determine that the estimated gas leakage source position is distant, the lines corresponding to the lines o and p are on the same screen in the time series of the gas flux with respect to the gas detector. Only two lines are displayed for the gas detector having the maximum value and the gas detector having the next largest value among the maximum values, and the alarm is not particularly sounded.

In this way, even if a highly sensitive gas detector is used, the troublesomeness of giving an alarm by mistake is released, and for the danger, the sensitivity of the gas detector is maximized and the gas is detected at an early stage. The source of leakage can be estimated.

[0068]

As is apparent from the above description, according to the method for estimating the gas leak point and the leak amount according to the present invention,
Calculate the gas flux value at each gas detector position by processing the measurement data from multiple gas detectors and the measurement data from the anemometers in the vicinity or at the same place, and calculate the gas flux and its direction. The gas leak point and the gas leak amount are calculated from the above, and the point where the gas leak amount corresponding to each gas detector matches each other is judged as the gas leak point, so that the gas leak point and the leak amount are estimated early and accurately. can do.

[Brief description of drawings]

FIG. 1 is a diagram showing a positional relationship between a gas detector and a gas leak point.

FIG. 2 is a block diagram showing a configuration of a gas leakage monitoring system to which the present invention is applied.

FIG. 3 is a diagram showing a display example on a CRT display device in estimating a gas leak point.

FIG. 4 is a diagram illustrating display symbols in FIG.

FIG. 5 is a diagram showing a display example on a CRT display device in estimating a gas leak point.

FIG. 6 is a diagram showing a display example on a CRT display device in estimating a gas leak point.

[Explanation of symbols]

 1 gas concentration data collection storage device 2 wind direction wind speed data collection storage device 3 data processing device 4 keyboard 5 gas detector position storage device 6 external storage device 7 alarm device 8 CRT display device 9 printer G (1) to G (12) gas Detector B (1) to B (4) Wind direction anemometer

Claims (3)

[Claims] 1. A gas leak point and a gas leak amount are estimated from gas concentration data from a plurality of gas detectors within a certain area and wind direction and wind speed data from an anemometer installed near the gas detectors. Is a method for obtaining the value of the gas flux for each of the gas detectors by multiplying the gas concentration data and wind speed data, the maximum value of the value of the gas flux within a predetermined time in the past , And a vector having the wind direction at that time is obtained while updating for each of the gas detectors, two gas detectors having the vector are selected, and each of the gas detectors corresponding to each of the selected gas detectors is selected. Find a line that extends the vector through the gas detector and its intersection, assuming that the intersection is the gas leak point and that each selected gas detector is just downwind of the gas leak point. Gas diffusion expressing a parameter determined by gas concentration, wind speed and weather conditions in a gas detector, a positional relationship between a gas leak point and the gas detector, and a relationship between the parameter and the positional relationship. Each of the estimated values of the gas leakage amount obtained from the formula is determined, and when the estimated values of the respective gas leakage amounts coincide with each other, the intersection is determined as a true gas leakage point, and the estimated values of the respective gas leakage amounts are If they do not match each other, it is assumed that there is a true gas leakage point on the line connecting the specific gas detector corresponding to the larger one of the estimated values of the gas leakage amounts and the intersection, and at each point on the line. Assuming that the point is a gas leak point, an estimated value of the gas leakage amount corresponding to each of the selected gas detectors is obtained, and an estimated value of the gas leakage amount corresponding to each of the selected gas detectors is True gas leakage at points that match each other Estimation method for a gas leakage points and the leakage amount and determines that. 2. A gas leak point and a gas leak amount are estimated from gas concentration data from a plurality of gas detectors within a certain area and wind direction and wind speed data from an anemometer installed near the gas detectors. Is a method for obtaining the value of the gas flux for each of the gas detectors by multiplying the gas concentration data and wind speed data, the maximum value of the value of the gas flux within a predetermined time in the past , And a vector with the wind direction at that time being updated while being updated for each of the gas detectors, selecting two specific gas detectors having the vector, and corresponding to each of the selected gas detectors Lines that extend each vector so as to pass through the gas detector and their intersections are obtained, and it is determined that there is a gas leakage point near the intersections, and at each gas detector selected near the intersections. Gas obtained from a gas diffusion formula expressing the parameters determined by the gas concentration, wind speed and meteorological conditions, the positional relationship between the gas leak point and the gas detector, and the relationship between the parameters and the positional relationship. Obtaining a curve that agrees with the estimated value of the leakage amount, the vector updated in a predetermined time further in each of the selected gas detectors or the stored past vector or the value of the current gas flux It is characterized in that a curve that matches the estimated value of each gas leakage amount is obtained from a vector having a size and the current wind direction is the same, and that the intersection of each curve is determined as a true gas leakage point. Method of estimating gas leak point and leak amount. 3. When there are two each of the first-obtained curve and the two curves obtained after a lapse of a predetermined time, and there are two intersections, the vector updated after a lapse of the predetermined time or stored. The above-mentioned vector in the past or the value of the current gas flux is set as a magnitude, and a curve in which the estimated values of the respective gas leak amounts coincide with each other is obtained from the vector in which the current wind direction is oriented, and the first obtained The gas leak point and the leak amount according to claim 2, wherein the intersection point on the side where the curve, the curve obtained the second time, and the curve obtained the third time intersect each other is determined as the true gas leak point. Estimation method. [0001]