Gas leakage detection method and gas leakage detection system

Abstract

To provide a method for detecting gas leakage and a gas leakage detection system capable of detecting a gas leak from a detection target containing a gas including poorly combustible ammonia even at a position distant from the detection target.SOLUTION: A gas leakage detection method includes: a temperature distribution acquisition step of acquiring, by using an infrared camera, the temperature distribution of a detection area including a detection target in which ammonia-containing gas is present inside; and a detection step of detecting leakage of the ammonia-containing gas by taking into consideration the temperature distribution of the detection area obtained in the temperature distribution acquisition step.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a gas leak detection method and a gas leak detection system for detecting leaks of gases containing ammonia. [Background technology]

[0002] Patent document 1 discloses an invention that determines whether hydrogen gas is leaking by placing multiple temperature measuring devices near equipment containing hydrogen gas and using the temperature measuring devices to detect temperature increases caused by ignition of hydrogen gas leaking from the equipment. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-242571 Summary of the Invention [Problem to be solved by the invention]

[0004] The invention described in Patent Document 1 may have difficulty in detecting gas leaks when the gas to be detected for leaks contains ammonia, which is poorly flammable. Also, when the object to be detected for leaks is a pipe or the like, it may be difficult to arrange multiple temperature measuring instruments around the object.

[0005] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a gas leak detection method and a gas leak detection system that can detect gas leaks from a detection object containing a gas containing poorly flammable ammonia even at a location away from the detection object. [Means for solving the problem]

[0006] A gas leak detection method according to at least one embodiment of the present disclosure includes: A gas leak detection method for detecting a leak of a gas containing ammonia, comprising: a temperature distribution acquisition step of acquiring a temperature distribution of a detection area including a detection object having the gas present therein by an infrared camera; and a detection step of detecting the gas leakage in consideration of the temperature distribution in the detection area obtained in the temperature distribution acquisition step.

[0007] A gas leak detection system according to at least one embodiment of the present disclosure comprises: A gas leak detection system for detecting leaks of a gas containing ammonia, At least one infrared camera configured to acquire a temperature distribution of a detection area including a detection object in which the gas is present; and a detection device that detects the gas leakage in consideration of the temperature distribution in the detection area obtained by imaging the detection area with the at least one infrared camera. [Effects of the Invention]

[0008] According to at least one embodiment of the present disclosure, there is provided a gas leak detection method and a gas leak detection system that can detect gas leaks from a detection object containing gas containing poorly flammable ammonia even at a location away from the detection object. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a gas leak detection system according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is an explanatory diagram illustrating an example of a detection area according to an embodiment of the present disclosure. [Figure 3] 10 is an explanatory diagram for explaining information acquired by an infrared camera from a detection area according to an embodiment of the present disclosure. FIG. [Figure 4] FIG. 1 is a flow diagram of a gas leak detection method according to an embodiment of the present disclosure. [Figure 5] FIG. 10 is an explanatory diagram for explaining a method for calculating the volume of a gas leakage region according to an embodiment of the present disclosure. [Figure 6]1 is a table illustrating the relationship between the volume of a leakage region, a temperature change, and a gas leakage rate in one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure.

[0011] (Gas Leak Detection System) 1 is a schematic diagram of a gas leak detection system 1 according to an embodiment of the present disclosure. The gas leak detection system 1 and gas leak detection method according to some embodiments of the present disclosure are systems (methods) for detecting leaks of gas containing ammonia. In the illustrated embodiment, the gas leak detection system 1 includes at least one infrared camera 4 (in the illustrated example, multiple infrared cameras 4), a detection device 5, and an alarm device 6. The infrared camera 4 is configured to capture an image of a detection area 3 including a detection target 2 containing a gas containing ammonia present therein, capture an image of the detection area 3, and obtain a temperature distribution in the captured detection area 3.

[0012] FIG. 1 shows a consumption facility (e.g., an engine) 11 for consuming ammonia-containing gas, a storage device (e.g., a gas tank) 12 configured to store the ammonia-containing gas, a gas inlet pipe 13 for guiding the ammonia-containing gas from the storage device 12 to the consumption facility 11, and a gas outlet pipe 14 for discharging exhaust gas from the consumption facility 11.

[0013] 1, the gas inlet pipe 13 and the gas outlet pipe 14 are each the detection object 2, but only one of the gas inlet pipe 13 or the gas outlet pipe 14 may be the detection object 2. In addition, the consumption equipment 11 or the storage device 12 may be the detection object 2, or two or more consecutive pieces of equipment or devices, such as a combination of the storage device 12 and the gas inlet pipe 13, may be the detection object 2.

[0014] (infrared camera) The same detection area 3 may be the object of imaging by multiple infrared cameras 4 (4A, 4B). In the embodiment shown in FIG. 1, the detection area 3 including the gas inlet pipe 13 is the object of imaging by two infrared cameras 4 (first infrared camera 4A, second infrared camera 4B). Also, the detection area 3 including the gas outlet pipe 14 is the object of imaging by two infrared cameras 4 (first infrared camera 4A, second infrared camera 4B). The multiple infrared cameras 4 imaging the same detection area 3 are preferably arranged so that they can image the detection area 3 from multiple directions.

[0015] FIG. 2 is an explanatory diagram illustrating an example of the detection area 3 according to an embodiment of the present disclosure. FIG. 3 is an explanatory diagram illustrating information acquired by the infrared camera 4 from the detection area 3 according to an embodiment of the present disclosure. The detection area 3 illustrated in FIG. 2 includes a first gas introduction pipe 131, a second gas introduction pipe 132, and a joint 133 connecting the first gas introduction pipe 131 and the second gas introduction pipe 132. The infrared camera 4 acquires information indicating the temperature distribution in the detection area 3 as illustrated in FIG. 3 by capturing an image of the detection area 3 illustrated in FIG. 2. The information indicating the temperature distribution in the detection area 3 includes information that enables a temperature image of the detection area 3 to be generated. The information that enables a temperature image to be generated includes information regarding the temperature of each mapping area obtained by dividing the captured image of the detection area 3 into a plurality of mapping areas each having a predetermined area unit, and information regarding the position of the mapping area in the captured image.

[0016] The detection device 5 is configured to receive information (signals) indicating the temperature distribution in the detection area 3 from the infrared camera 4 at predetermined intervals. If the infrared camera 4 is configured to generate the above-mentioned temperature image, the detection device 5 may be configured to acquire image data of the temperature image from the infrared camera 4.

[0017] The detection device 5 is configured to detect gas leaks by taking into account the temperature distribution in the detection area 3 obtained by capturing an image of the detection area 3 with the infrared camera 4. The detection device 5 (controller) is an electronic control unit for detecting gas leaks. The detection device 5 may be configured with an analog circuit that can be manufactured relatively inexpensively, or may be configured as a microcomputer including a CPU (processor) (not shown), memories such as ROM and RAM, a storage device such as an external storage device, an I / O interface, a communication interface, etc. If the detection device 5 is configured with a microcomputer, the processor operates (calculates, etc.) according to instructions of a program loaded into the memory, thereby realizing processing for detecting gas leaks. The detection device 5 includes a memory unit 51 that stores information used in the processing for detecting gas leaks and information acquired from the infrared camera 4, and a processing execution unit 52 that realizes processing for detecting gas leaks.

[0018] 4 is a flow diagram of a gas leak detection method according to an embodiment of the present disclosure. As shown in FIG. 4, the gas leak detection method includes a temperature distribution acquisition step S11 and a detection step (leak location identification step) S12. In the temperature distribution acquisition step S11, the temperature distribution of the detection area 3 is acquired by the infrared camera 4. In the detection step S12, a gas leak is detected in consideration of the temperature distribution of the detection area 3 acquired in the temperature distribution acquisition step S11. The detection step S12 and several steps S13 to S20, which will be described later, may be performed by a processing execution unit 52 of the detection device 5.

[0019] The infrared camera 4 can acquire the temperature distribution in the detection area 3, specifically, the surface temperature of the detection object 2 and the ambient temperature around the detection object 2. The infrared camera 4 can be placed at a position away from the detection object 2. When a gas leak occurs from the detection object 2, changes occur in the surface temperature of the detection object 2 and the ambient temperature around the detection object 2, so by taking the temperature distribution in the detection area 3 into consideration, it is possible to detect the leakage of gas containing ammonia, which is poorly flammable. The present disclosure is suitably applicable when the detection object 2 is a storage device 12, a gas inlet pipe 13, or a gas outlet pipe 14, and can detect the leakage of gas containing ammonia from these detection objects 2.

[0020] In some embodiments, in the detection step S12 described above, the temperature distribution map (captured image) of the detection area 3 is divided into a plurality of mapping areas (reference symbol R in FIG. 5) of a predetermined area unit, and the temperature difference between each mapping area and surrounding mapping areas (mapping areas aligned vertically, horizontally, or diagonally with respect to the mapping area to be determined) is obtained, and if there is a mapping area where the temperature difference is greater than a threshold value, it is determined that a gas leak has occurred. In one embodiment, if the temperature difference between the mapping area to be determined and surrounding mapping areas is greater than a threshold value (e.g., 10°C), it is determined that a gas leak has occurred. It is preferable that the gas leakage determination is performed for all mapping areas included in the detection area 3.

[0021] When a gas leak occurs from the detection object 2, a change occurs in the surface temperature of the detection object 2 and the ambient temperature around the detection object 2. When the temperature difference with respect to the surroundings becomes larger than a threshold value, it can be determined that a gas leak has occurred.

[0022] In some embodiments, the temperature distribution acquisition step S11 described above includes a first temperature distribution acquisition step and a second temperature distribution acquisition step. In the first temperature distribution acquisition step, the first infrared camera 4A acquires the temperature distribution of the detection area 3. In the second temperature distribution acquisition step, the second infrared camera 4B, whose imaging direction intersects with the imaging direction of the first infrared camera 4A, acquires the temperature distribution of the same detection area 3 as that of the first infrared camera 4A.

[0023] In one embodiment, the first infrared camera 4A is placed in a position where it can acquire information that allows a horizontal plane image to be created as a temperature distribution map, and the second infrared camera 4B is placed in a position where it can acquire information that allows a vertical plane image to be created as a temperature distribution map. The imaging direction of the first infrared camera 4A is along the vertical direction, and the imaging direction of the second infrared camera 4B is along the horizontal direction.

[0024] In the above-mentioned detection step S12, gas leakage is detected in consideration of both the temperature distribution of the detection area 3 obtained in the first temperature distribution acquisition step and the temperature distribution of the detection area 3 obtained in the second temperature distribution acquisition step. For example, the temperature difference for each mapping area may be calculated from the information acquired by the first infrared camera 4A and the calculated temperature difference may be used to determine whether or not there is a gas leakage, and the temperature difference for each mapping area may be calculated from the information acquired by the second infrared camera 4B and the calculated temperature difference may be used to determine whether or not there is a gas leakage.

[0025] The first infrared camera 4A and the second infrared camera 4B can acquire the temperature distribution from two directions in the same detection area 3. By taking into account the temperature distribution from two directions in the same detection area 3, gas leakage can be detected with higher accuracy.

[0026] (Identifying gas leak locations) In a gas leak detection method according to some embodiments, the detection step S12 described above includes a leak location identification step of identifying the location of a gas leak based on both the temperature distribution of the detection area 3 obtained in the first temperature distribution acquisition step described above and the temperature distribution of the detection area 3 obtained in the second temperature distribution acquisition step described above. In the embodiment shown in Fig. 4, if the gas leak location can be identified in the leak location identification step ("Yes" in step S13), a volume calculation step S14 described below is performed. If the gas leak location cannot be identified in the leak location identification step ("No" in step S13), the temperature distribution acquisition step S11 and the leak location identification step described above are repeated until the gas leak location can be identified in the leak location identification step.

[0027] The first infrared camera 4A and the second infrared camera 4B can acquire temperature distributions from two directions in the same detection area 3. Then, a portion in the same detection area 3 where the temperature difference is relatively large can be identified as the location of the gas leak.

[0028] (Estimation of gas leak concentration) Fig. 5 is an explanatory diagram illustrating a method for calculating the volume of a gas leakage region in an embodiment of the present disclosure. Fig. 6 is a table illustrating the relationship between the volume of a leakage region, temperature change, and gas leakage rate in an embodiment of the present disclosure. A gas leakage detection method according to some embodiments includes a volume calculation step S14 that calculates the volume of the gas leakage region based on both the temperature distribution of the detection area 3 obtained in the first temperature distribution acquisition step described above and the temperature distribution of the detection area 3 obtained in the second temperature distribution acquisition step described above.

[0029] 5, in the volume calculation step S14, among the multiple mapping regions R in the horizontal plane image (temperature distribution map) TI1 acquired by the first infrared camera 4A, a region where the temperature difference is relatively large (a region where the temperature difference is larger than the threshold) is identified as the gas leakage region A1 in the horizontal plane image TI1. Among the multiple mapping regions R in the vertical plane image (temperature distribution map) TI2 acquired by the second infrared camera 4B, a region where the temperature difference is relatively large (a region where the temperature difference is larger than the threshold) is identified as the gas leakage region A2 in the vertical plane image TI2. The volume of the block formed by the gas leakage region A1 and the gas leakage region A2 is calculated as the volume V of the gas leakage region A0.

[0030] The gas leak detection method according to some embodiments further includes a gas leak rate estimation step S15 for estimating the gas leak rate m in the leak area A0 from the temperature change ΔT in the leak area A0 and the volume V of the leak area A0 calculated in the volume calculation step S14, based on association information (see, for example, FIG. 6 ) that associates the volume V of the leak area A0, the temperature change ΔT, and the gas leak rate m. The association information is stored in advance in the storage unit 51, and the processing execution unit 52 refers to the association information stored in the storage unit 51.

[0031] The association information indicates the correspondence relationship between the volume V of the leakage region A0, the temperature change ΔT, and the gas leakage rate m, and may be any information that can acquire the gas leakage rate m of the leakage region A0 corresponding to the input information as output information when the volume V of the leakage region A0 and the temperature change ΔT are input information. The association information may include not only the table shown in FIG. 6 but also lists, maps, functions, machine learning models, strength analysis models, etc. that indicate the correspondence relationship between the input information and the output information. The association information may be created based on the results of numerical analysis.

[0032] Specifically, a certain time is defined as t0, a time after a predetermined period (unit time, e.g., 1 second) has elapsed since time t0 is defined as t1, and a time after a predetermined period (unit time, e.g., 1 second) has elapsed since time t1 is defined as t2. The volume of the gas leakage area A0 at time t0 is defined as V0, and the temperature of the leakage area A0 at time t0 is defined as T0. Similarly, the volume of the gas leakage area A0 at time t1 is defined as V1, the temperature of the leakage area A0 at time t1 is defined as T1, the volume of the gas leakage area A0 at time t2 is defined as V2, and the temperature of the leakage area A0 at time t2 is defined as T2. The temperature change ΔT1 during the period from time t0 to time t1 can be calculated by T1 - T0. The temperature change ΔT2 during the period from time t1 to time t2 can be calculated by T2 - T1. The above-mentioned unit time may be 10 seconds or 1 minute.

[0033] The volume V (V0, V1, V2) of the leakage area A0 is calculated in volume calculation step S14. The temperature T (T0, T1, T2) of the leakage area A0 is the average value of the temperatures of the leakage area A0 acquired by the infrared camera 4. The temperature T of the leakage area A0 may be acquired from a temperature distribution map such as the horizontal plane image TI1 or vertical plane image TI2 described above. The temperature T (T0, T1, T2) of the leakage area A0 may be the average value of the temperatures of the leakage area A1 acquired by the first infrared camera 4A, the average value of the temperatures of the leakage area A2 acquired by the second infrared camera 4B, or the average value of the temperatures of the leakage area A1 acquired by the first infrared camera 4A and the temperatures of the leakage area A2 acquired by the second infrared camera 4B.

[0034] The gas leakage rate m1(m) at time t1 can be estimated from the volume V1 and the temperature change ΔT1 based on the association information. The gas leakage rate m2(m) at time t2 can be estimated from the volume V2 and the temperature change ΔT2 based on the association information. In the example shown in FIG. 6, if the volume V of the leakage area A0 is CC and the temperature change ΔT of the leakage area A0 is 6°C / min, the corresponding C3 is calculated as the gas leakage rate m. Note that when estimating the gas leakage rate m at a certain time, the volume at that time may be used instead of the volume at that time.

[0035] The first infrared camera 4A and the second infrared camera 4B can acquire the temperature distribution of the detection area 3 from two directions. Then, the area in the detection area 3 where the temperature difference is relatively large is determined to be the gas leakage area A0, and the volume V of the gas leakage area A0 can be calculated. By utilizing the relationship between the volume V of the leakage area A0, the temperature change ΔT, and the gas leakage speed m, the gas leakage speed m in the leakage area A0 can be accurately estimated from the volume V of the leakage area A0 and the temperature change ΔT.

[0036] A gas leak detection method according to some embodiments includes gas concentration estimation steps S16 and S17 for estimating the concentration of gas in the space based on the temperature change time of the leak area A0, the gas leakage rate m in the leak area estimated in gas leakage rate estimation step S15, and the spatial volume of the space including the detection area 3. The gas leakage amount M can be calculated from the temperature change time of the leak area A0 and the gas leakage rate m in the leak area A0 estimated in gas leakage rate estimation step S15 (step S16). Then, the gas concentration in the space can be calculated from the calculated gas leakage amount M and the spatial volume of the space including the detection area 3 (step S17).

[0037] The gas leakage amount M can be calculated by integrating the gas leakage amount per unit time. Specifically, the gas leakage amount M1(M) at time t1 can be calculated by multiplying the gas leakage rate m1 at time t1 by the predetermined time (temperature change time). The gas leakage amount M2(M) at time t2 can be calculated by multiplying the gas leakage rate m2 at time t2 by the predetermined time (temperature change time) and adding the gas leakage amount M1 at time t1 to the result. The gas concentration in the space at time t1 can be calculated by dividing the gas leakage amount M1 by the spatial volume of the space. The gas concentration in the space at time t2 can be calculated by dividing the gas leakage amount M2 by the spatial volume of the space.

[0038] The amount of gas leakage can be estimated from the gas leakage rate m and the temperature change time in the leakage area A0, and the gas concentration in the space can be accurately estimated from the estimated gas leakage amount and the spatial volume of the space including the detection area 3. By estimating the gas concentration in the space, it becomes possible to take appropriate countermeasures against the gas leak.

[0039] A gas leak detection method according to some embodiments includes notification steps S18, S19, and S20 in which, when the gas concentration in the space estimated in the gas concentration estimation steps S16 and S17 is equal to or greater than a predetermined concentration, the notification device 6 issues a different notification than when the concentration is less than the predetermined concentration. The notification device 6 may be a display device capable of displaying visualized information, such as a display, or an acoustic device capable of generating notification sounds, such as voice or warning sounds, such as a speaker. In some embodiments, when the gas concentration in the space is less than the predetermined concentration ("No" in step S18), a warning is issued (step S19). When the gas concentration in the space is equal to or greater than the predetermined concentration ("Yes" in step S18), a warning is issued (step S20). Note that when the gas concentration in the space is equal to or greater than the predetermined concentration ("Yes" in step S18), an interlock (safety device), such as stopping the consumption equipment 11, may be activated. In the illustrated embodiment, after the attention alert is issued (step S19), steps S11 to S18 are repeated until the answer in step S18 is "Yes."

[0040] In this specification, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement strictly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. Furthermore, in this specification, expressions representing shapes such as a rectangular shape or a cylindrical shape not only represent rectangular shapes or cylindrical shapes in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. Furthermore, in this specification, the expressions "comprise," "include," or "have" a component are not exclusive expressions that exclude the presence of other components.

[0041] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0042] The contents of the above-described embodiments can be understood, for example, as follows.

[0043] 1) A gas leak detection method according to at least one embodiment of the present disclosure includes: A gas leak detection method for detecting a leak of a gas containing ammonia, comprising: a temperature distribution acquisition step (S11) of acquiring a temperature distribution of a detection area (3) including a detection object (2) having the gas present therein by an infrared camera (4); and a detection step (S12) of detecting the gas leakage in consideration of the temperature distribution in the detection area (3) obtained in the temperature distribution acquisition step (S11).

[0044] According to the method 1) above, the temperature distribution in the detection area 3, specifically, the surface temperature of the detection object 2 and the ambient temperature around the detection object 2, can be acquired by the infrared camera 4. The infrared camera 4 can be placed at a position away from the detection object 2. When a gas leak occurs from the detection object 2, the surface temperature of the detection object 2 and the ambient temperature around the detection object 2 change. Therefore, by taking into account the temperature distribution in the detection area 3, it is possible to detect the leakage of gases containing ammonia, which has poor flammability.

[0045] 2) In some embodiments, the gas leak detection method according to 1) above comprises: In the detection step (S12), A temperature image showing the temperature distribution in the detection area (3) is divided into a plurality of mapping areas of a predetermined area unit, and the temperature difference between each mapping area and the surrounding mapping areas is obtained, and if the temperature difference becomes larger than a threshold value, it is determined that the gas is leaking.

[0046] According to the method 2), when a gas leak occurs from the detection object 2, a change occurs in the surface temperature of the detection object 2 and the ambient temperature around the detection object 2. When the temperature difference becomes larger than a threshold value, it can be determined that a gas leak has occurred.

[0047] 3) In some embodiments, the gas leak detection method according to 1) or 2) above comprises: The temperature distribution acquisition step (S11) a first temperature distribution acquisition step of acquiring a temperature distribution in the detection area (3) by a first infrared camera (4A); a second temperature distribution acquisition step of acquiring a temperature distribution in the detection area (3) by a second infrared camera (4B) whose imaging direction intersects with the imaging direction of the first infrared camera (4A), In the detection step, the gas leakage is detected taking into consideration both the temperature distribution of the detection area (3) obtained in the first temperature distribution acquisition step and the temperature distribution of the detection area (3) obtained in the second temperature distribution acquisition step.

[0048] According to the method 3), the temperature distribution of the detection area 3 from two directions can be acquired using the first infrared camera 4A and the second infrared camera 4B. By taking into account the temperature distribution of the detection area 3 from two directions, gas leakage can be detected more accurately.

[0049] 4) In some embodiments, the gas leak detection method according to 3) above comprises: The detection step (S12) The method includes a leak location identification step of identifying the location of the gas leak based on both the temperature distribution of the detection area (3) obtained in the first temperature distribution acquisition step and the temperature distribution of the detection area (3) obtained in the second temperature distribution acquisition step.

[0050] According to the method 4) above, the temperature distribution of the same detection area (3) can be acquired from two directions using the first infrared camera (4A) and the second infrared camera (4B).Then, a portion of the same detection area (3) where the temperature difference with respect to the surroundings is relatively large can be identified as the location of the gas leak.

[0051] 5) In some embodiments, the gas leak detection method according to 3) or 4) above, a volume calculation step (S14) of calculating a volume (V) of the gas leakage area (A0) based on both the temperature distribution of the detection area obtained in the first temperature distribution acquisition step and the temperature distribution of the detection area obtained in the second temperature distribution acquisition step; The method further includes a gas leakage rate estimation step (S15) of estimating the gas leakage rate (m) in the leakage area from the temperature change (ΔT) in the leakage area (A0) and the volume (V) of the leakage area (A0) calculated in the volume calculation step (S14) based on association information that associates the volume (V) of the leakage area (A0), the temperature change (ΔT), and the gas leakage rate (m).

[0052] According to the method of 5) above, the temperature distribution of the detection area (3) can be acquired from two directions using the first infrared camera (4A) and the second infrared camera (4B). Then, an area in the detection area (3) where the temperature difference with respect to the surroundings is relatively large is determined to be the gas leakage area (A0), and the volume (V) of the gas leakage area (A0) can be calculated. By utilizing the relationship between the volume (V) of the leakage area (A0), the temperature change (ΔT), and the gas leakage speed (m), the gas leakage speed (m) in the leakage area (A0) can be accurately estimated from the volume (V) and temperature change (ΔT) of the leakage area (A0).

[0053] 6) In some embodiments, the gas leak detection method described in 5) above comprises: The method includes gas concentration estimation steps (S16, S17) for estimating the concentration of the gas in the space based on the temperature change time of the leak area (A0), the gas leakage rate (m) in the leak area (A0) estimated in the gas leakage rate estimation step (S15), and the spatial volume of the space including the detection area (3).

[0054] According to the method 6) above, the amount of gas leakage (M) can be estimated from the gas leakage speed (m) and the temperature change time in the leakage area (A0), and the gas concentration in the space can be estimated with high accuracy from the estimated amount of gas leakage (M) and the spatial volume of the space including the detection area (3). By estimating the gas concentration in the space, it becomes possible to take appropriate countermeasures against the gas leak.

[0055] 7) In some embodiments, the gas leak detection method described in 6) above comprises: The method further includes an alarm step (S18, S19, S20) in which, when the gas concentration in the space estimated in the gas concentration estimation step (S16, S17) is equal to or greater than a predetermined concentration, an alarm device (6) issues an alarm different from that issued when the concentration is less than the predetermined concentration.

[0056] According to the method 7) above, the alarm device (6) issues an alarm according to the concentration of gas in the space, so that the person who receives the alarm can be encouraged to take appropriate action according to the concentration of gas in the space.

[0057] 8) In some embodiments, the gas leak detection method according to any one of 1) to 7) above, The object to be detected (2) includes a gas introduction pipe (13) for introducing the gas to a consumption facility (11) for consuming the gas.

[0058] According to the method 8), even when the detection object (2) includes the gas introduction pipe (13), gas leakage from the gas introduction pipe (13) can be detected with high accuracy by taking into consideration the change in temperature distribution in the detection area (3) over time.

[0059] 9) In some embodiments, the gas leak detection method according to any one of 1) to 7) above, The object to be detected (2) includes a gas exhaust pipe (14) for discharging exhaust gas from a consumption facility (11) for consuming the gas.

[0060] According to the method 9), even when the detection object (2) includes the gas exhaust pipe (14), gas leakage from the gas exhaust pipe (14) can be detected with high accuracy by taking into consideration the change in temperature distribution in the detection area (3) over time.

[0061] 10) At least one embodiment of the gas leak detection system (1) of the present disclosure includes: A gas leak detection system (1) for detecting leaks of a gas containing ammonia, At least one infrared camera (4) configured to acquire a temperature distribution of a detection area (3) including a detection object (2) in which the gas exists; and a detection device (5) that detects the gas leakage in consideration of the temperature distribution in the detection area (3) obtained by imaging the detection area (3) with the at least one infrared camera (4).

[0062] According to the configuration of 10) above, the infrared camera (4) can acquire the temperature distribution in the detection area (3), specifically, the surface temperature of the detection object (2) and the ambient temperature around the detection object (2). The infrared camera (4) can be placed at a position away from the detection object (2). When a gas leak occurs from the detection object (2), the surface temperature of the detection object (2) and the ambient temperature around the detection object (2) change. Therefore, the detection device (5) can detect the leakage of gas containing ammonia, which is poorly flammable, by taking into account the temperature distribution in the detection area (3). [Explanation of symbols]

[0063] 1. Gas leak detection system 2. Object to be detected 3 Detection area 4. Infrared camera 4A First infrared camera 4B Second infrared camera 5. Detection Device 6. Alarm device

Claims

1. A gas leak detection method for detecting a leak of a gas containing ammonia, comprising: a temperature distribution acquisition step of acquiring a temperature distribution of a detection area including a detection object having the gas present therein by an infrared camera; a detection step of detecting leakage of the gas in consideration of the temperature distribution in the detection area obtained in the temperature distribution acquisition step. Gas leak detection methods.

2. In the detecting step, a temperature image showing the temperature distribution in the detection area is divided into a plurality of mapping areas each having a predetermined area unit, and a temperature difference between each mapping area and a surrounding mapping area is obtained; and if the temperature difference is greater than a threshold value, it is determined that the gas is leaking. The gas leak detection method according to claim 1 .

3. The temperature distribution acquisition step includes: a first temperature distribution acquisition step of acquiring a temperature distribution of the detection area by a first infrared camera; a second temperature distribution acquisition step of acquiring a temperature distribution in the detection area by a second infrared camera whose imaging direction intersects with the imaging direction of the first infrared camera, In the detection step, the gas leakage is detected in consideration of both the temperature distribution in the detection area obtained in the first temperature distribution acquisition step and the temperature distribution in the detection area obtained in the second temperature distribution acquisition step. The gas leakage detection method according to claim 1 or 2.

4. The detecting step a leak location identifying step of identifying a location of the gas leak based on both the temperature distribution in the detection area obtained in the first temperature distribution acquiring step and the temperature distribution in the detection area obtained in the second temperature distribution acquiring step, The gas leak detection method according to claim 3.

5. a volume calculation step of calculating a volume of the gas leakage region based on both the temperature distribution of the detection area obtained in the first temperature distribution acquisition step and the temperature distribution of the detection area obtained in the second temperature distribution acquisition step; a gas leakage rate estimation step of estimating the leakage rate of the gas in the leakage region from the temperature change in the leakage region and the volume of the leakage region calculated in the volume calculation step, based on association information that associates the volume of the leakage region, the temperature change, and the leakage rate of the gas, The gas leak detection method according to claim 3.

6. a gas concentration estimation step of estimating the concentration of the gas in the space based on a temperature change time of the leak area, the leak rate of the gas in the leak area estimated in the gas leak rate estimation step, and a spatial volume of the space including the detection area; The gas leak detection method according to claim 5.

7. a notification step of, when the concentration of the gas in the space estimated in the gas concentration estimation step is equal to or higher than a predetermined concentration, making a notification by a notification device that is different from a notification made when the concentration is lower than the predetermined concentration; The gas leak detection method according to claim 6.

8. The object to be detected includes a gas introduction pipe for introducing the gas to a consumption facility for consuming the gas. The gas leakage detection method according to claim 1 or 2.

9. The detection object includes a gas exhaust pipe for discharging exhaust gas from a consumption facility for consuming the gas. The gas leakage detection method according to claim 1 or 2.

10. A gas leak detection system for detecting leaks of a gas containing ammonia, at least one infrared camera configured to acquire a temperature distribution of a detection area including a detection object having the gas present therein; a detection device that detects the gas leakage in consideration of the temperature distribution in the detection area obtained by imaging the detection area with the at least one infrared camera, Gas leak detection system.

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