WO2018043421A1 - Piping evaluation device, piping evaluation method, and piping evaluation program - Google Patents

Abstract

This piping evaluation device is provided with: an infrared image acquisition unit that acquires an infrared image which is obtained by photographing a monitoring region including heat-insulated piping in a plant; a comparison unit that compares a first temperature distribution and a second temperature distribution of the heat-insulated piping acquired by the infrared image acquisition unit, and generates a temperature difference distribution; and a water-containing state determination unit that determines the water-containing state of the heat-insulated piping on the basis of the temperature difference distribution.

Description

Pipe evaluation device, pipe evaluation method and pipe evaluation program

The present invention relates to a pipe evaluation apparatus, a pipe evaluation method, and a pipe evaluation program for grasping the corrosion status of a heat insulating pipe.

Conventionally, a device using infrared rays is known as a gas leak detection device for detecting a gas leak (for example, Patent Documents 1 to 3). The gas leak detection device disclosed in Patent Document 1 irradiates infrared rays having a specific wavelength absorbed by a detection target gas (for example, methane gas) toward a monitoring target region, and the intensity of the infrared rays having the specific wavelength reflected by the target object. Based on the above, leakage of the detection target gas is detected. In addition to the detection of the detection target gas disclosed in Patent Document 1, the gas leak detection device disclosed in Patent Document 2 uses various infrared gases based on infrared energy emitted by the object. Leakage can be detected. Patent Document 3 discloses that the position of the leaking gas is specified by pattern matching, and the gas leakage amount is estimated by the concentration thickness product of the leaking gas cloud.

On the other hand, in plant piping, gas leakage from the joints and valves is unavoidable due to the structure. In a large plant that operates continuously for a long period of time, if the gas leakage has little impact on the environment and does not cause a problem, this is allowed and the operation is continued while observing. And when operation of a plant is stopped by regular repair or temporary repair, correspondence, such as parts exchange, is carried out as needed. This is based on the idea of ALARP (As Low Low As Reasonably Practicable) that eliminates accidents while suppressing excessive capital investment, and is described in Non-Patent Document 1.

By the way, the gas leak in the plant is mainly generated from the joint part and valve part of the pipe, but may also be generated from the corroded part of the pipe. Corrosion of heat insulation piping that is often used in plants is called CUI (Corrosion Under Insulation). In the heat insulating pipe, the outer peripheral surface of the pipe is covered with a heat insulating material, and the outer peripheral surface of the heat insulating material is further covered with an exterior material for rain curing (for example, an exterior material made of tin). Therefore, when moisture (for example, rainwater) enters the interior from the exterior material, it penetrates into the heat insulating material and repeats evaporation and condensation in a closed space between the pipe and the exterior material, which causes CUI. Conceivable.

CUI cannot be directly inspected by visual inspection without disassembling the insulation pipes and removing the exterior and insulation materials. Moreover, even if the flooded part (rust, seal failure, etc.) in the exterior material can be identified by visual observation, CUI does not always occur directly under the flooded part (the part that is different from the flooded part due to the movement of moisture inside the heat insulating material) Stay in). Therefore, it is very difficult to evaluate the CUI by nondestructive.

In Patent Document 4, as an example of nondestructive pipe evaluation, there is a method for detecting a water-containing part (part where CUI is likely to be generated) where moisture is retained based on the temperature distribution (infrared image) on the surface of the heat insulating pipe. It is disclosed. Moreover, in the method disclosed in Patent Document 4, an electrical conductivity is measured by inserting a needle-like electrode into the specified water-containing portion, and the water content associated with the electrical conductivity is used as an index for evaluating the soundness of piping. It is used as.

Japanese Patent Laid-Open No. 5-99778 Japanese Patent Laid-Open No. 2003-130752 JP 2016-114500 A JP-A-6-1118040

March 2006, Safety Section, Health and Safety Department, Ministry of Health, Labor and Welfare, “Guidelines for investigations on risks and toxicity (commonly known as risk assessment guidelines)” p. 24

However, the temperature distribution on the surface of the heat insulating pipe shown in the infrared image also reflects the temperature environment around the pipe, so even a non-water-containing part is displayed differently from the surroundings as if moisture is staying. Sometimes. Therefore, the method disclosed in Patent Document 3 may not be able to accurately identify the water-containing portion. In addition, the method disclosed in Patent Document 3 can measure the electrical conductivity even for a non-hydrous part where CUI is less likely to occur, and may evaluate the degree of corrosion of this part. bad. In addition, the method disclosed in Patent Document 3 may cause a CUI to be overlooked as a result of being unable to detect a water-containing part that is likely to generate CUI as a water-containing part.

An object of the present invention is to provide a pipe evaluation apparatus and a pipe that can easily and accurately identify a water-containing portion that is likely to be a CUI occurrence location, can accurately evaluate the soundness of the pipe, and can realize reasonable predictive maintenance. An evaluation method and a piping evaluation program are provided.

The pipe evaluation device according to one aspect of the present invention includes an infrared image acquisition unit that acquires an infrared image obtained by photographing a monitoring region including a heat insulating pipe of a plant,
A comparison unit that compares the first temperature distribution and the second temperature distribution of the heat insulating pipe acquired by the infrared image acquisition unit to generate a differential temperature distribution;
A water content determination unit that determines a water content in the heat insulating piping based on the differential temperature distribution.

The pipe evaluation method according to an aspect of the present invention includes a first step of acquiring an infrared image obtained by photographing a monitoring region including a heat insulating pipe of a plant,
A second step of generating a differential temperature distribution by comparing the first temperature distribution and the second temperature distribution of the heat insulating pipe obtained by the first step;
And a third step of determining a moisture content in the heat insulation pipe based on the difference temperature distribution.

The pipe evaluation program according to one aspect of the present invention is a computer for a pipe evaluation apparatus for evaluating the soundness of a heat insulating pipe in a plant.
A first process for acquiring an infrared image obtained by photographing a monitoring region including a heat insulating pipe of the plant;
A second process for generating a differential temperature distribution by comparing the first temperature distribution and the second temperature distribution of the heat insulating pipe obtained by the first process;
And a third process for determining a moisture content in the heat insulating pipe based on the difference temperature distribution.

According to the present invention, it is possible to easily and accurately identify a water-containing portion that is highly likely to be a CUI occurrence location, and to accurately evaluate the soundness of piping, thereby realizing rational predictive maintenance.

It is a figure which shows the piping evaluation apparatus which concerns on embodiment. It is a figure which shows the hardware constitutions of a control part. It is a figure which shows an example of the infrared image containing leakage gas. It is a flowchart which shows an example of piping evaluation processing. It is a figure which shows an example of reference temperature distribution. It is a figure which shows an example of the infrared image after raining. It is a figure which shows an example of difference temperature distribution. It is a figure which shows an example of the warning display of CUI.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a pipe evaluation device 1 according to an embodiment of the present invention. The pipe evaluation device 1 is for evaluating the soundness of the heat insulation pipe laid in the plant. Specifically, the pipe evaluation apparatus 1 detects leaking gas from the heat insulation pipe and determines the soundness of the heat insulation pipe.

1, the pipe evaluation device 1 includes a control unit 10, an infrared imaging unit 20, an input unit 31, a display unit 32, a communication unit 33, a storage unit 34, and the like. FIG. 2 is a diagram illustrating a hardware configuration of the control unit 10.

As shown in FIG. 2, the control unit 10 is a computer that includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, and a RAM (Random Access Memory) 103. For example, the CPU 101 reads a program corresponding to the processing content from the ROM 102 and develops it in the RAM 103, and centrally controls the operation of each block of the pipe evaluation device 1 in cooperation with the developed program. A pipe evaluation program to be described later is stored in the ROM 102, for example.

The control unit 10 functions as the infrared image acquisition unit 11, the comparison unit 12, the moisture content determination unit 13, the soundness evaluation unit 14, and the display control unit 15 by executing a program stored in the ROM 102. These functions will be described in detail according to the flowchart of FIG. In addition, you may implement | achieve the infrared image acquisition part 11, the comparison part 12, the moisture content judgment part 13, the soundness evaluation part 14, and the display control part 15 with a hardware circuit, respectively.

The infrared imaging unit 20 captures an image of a monitoring region including a heat insulating pipe of the plant, and sequentially outputs an infrared moving image V _ir as an example of an infrared image to the control unit 10. The infrared imaging unit 20 visualizes the leaked gas by utilizing the property of gas that absorbs infrared rays having a specific wavelength. If there is a gas leak from the insulated pipe, the infrared radiation emitted from the object behind the leaking gas is absorbed by the leaking gas, so in the infrared image showing the monitoring area, the leaking gas is like white smoke or black smoke. Is displayed (see FIG. 3).

FIG. 3 is an infrared image showing a state in which the leaking gas G is ejected from the joint portion of the heat insulating pipe P2. In FIG. 3, the surface temperatures of the heat insulating pipes P1 to P3 are shown in shades. In FIG. 3, the outline information of the visible image is combined with the infrared image in order to make the temperature distribution in the heat insulating pipes P1 to P3 easy to understand. The same applies to a diagram showing an infrared image (including a differential temperature distribution) described later.

The infrared imaging unit 20 is a camera including an optical system 21, an optical filter 22, an area image sensor 23 (two-dimensional image sensor), and a signal processing unit 24.

The optical system 21 causes the area image sensor 23 to form an image of the infrared ray IR ₀ that has entered from the monitoring region that is the subject.

The optical filter 22 is disposed on the optical path connecting the optical system 21 and the area image sensor 23, and allows only the infrared IR ₁ included in the predetermined wavelength band among the infrared IR ₀ that has passed through the optical system 21 to pass therethrough. The pass wavelength band of the optical filter 21 is substantially set to the absorption wavelength band of the gas to be detected. For example, when the pass wavelength band is set to the mid-wavelength range of 3.2 to 3.4 μm, methane gas or the like can be detected.

The area image sensor 23 performs photoelectric conversion on the infrared ray IR ₁ that has passed through the optical filter 22 to generate and output an analog electrical signal indicating an infrared image (thermal image) of the monitoring area. The operating principle and element material of the area image sensor 23 are appropriately selected depending on the pass wavelength band of the optical filter 22. For example, when the pass wavelength band is 3.2 to 3.4 μm, a cooled indium antimonide image sensor or the like is used as the area image sensor 23.

The signal processing unit 24 converts the analog signal from the area image sensor 23 into a digital signal to generate an infrared moving image V _ir . The signal processing unit 24 may perform known image processing as necessary. The signal processing unit 24, the generated infrared moving image V _ir was sequentially outputs to the control unit 10 at a predetermined frame rate. The infrared moving image V _ir is stored in a frame memory (not shown) in units of frames.

The input unit 31 includes a keyboard or a pointing device such as a mouse capable of inputting characters or a touch panel provided integrally with the display unit 32. The display unit 32 is a display such as a liquid crystal display or an organic EL display, and displays an infrared image captured by the infrared imaging unit 20. The communication unit 33 is a communication interface for accessing the weather information service via the Internet, for example, by wireless communication or wired communication.

The storage unit 34 is an auxiliary storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive). The storage unit 34 stores reference temperature distribution data 341 and the like. The reference temperature distribution data 331 is reference data (first temperature distribution) used when specifying a water-containing portion (portion in which moisture stays) in the heat insulating pipe. The reference temperature distribution data 331 is, for example, data indicating the temperature distribution during drying acquired in advance in the initial operation of the plant, that is, the temperature distribution of the heat insulation pipe when moisture is not retained in the heat insulation pipe (FIG. 5). reference).

In the pipe evaluation device 1, predetermined image processing is performed on the infrared moving image V _ir from the infrared imaging unit 20, and the infrared image of the monitoring area is displayed on the display unit 32 (processing as the display control unit 15). As shown in FIG. 3, the leakage gas G in the heat insulating pipes P1 to P3 can be detected from the infrared moving image V _ir (infrared image). For detection of the leaked gas G, for example, pattern matching and concentration-thickness product disclosed in Patent Document 3 are used. Furthermore, the pipe evaluation apparatus 1 can determine the soundness of the heat insulating pipes P1 to P3, in other words, the risk of gas leakage due to CUI (corrosion). Specifically, the risk of gas leakage by the CUI is determined according to the flowchart shown in FIG.

FIG. 4 is a flowchart showing the pipe evaluation process. This process is realized, for example, by calling and executing a pipe evaluation program stored in the ROM 102 by the CPU 101 when an operation for starting the pipe evaluation process is performed through the input unit 31.

In step S101 of FIG. 4, the control unit 10 determines whether or not it is after raining. Whether or not it is after raining is determined based on, for example, weather information (rainfall information) acquired through the communication unit 33. If it is after rain (“YES” in step S101), the process proceeds to step S102, and it is determined whether water has been newly submerged in the heat insulating pipe (whether the water content has increased). If it is not after rain (“NO” in step S101), the process proceeds to step S107, and the soundness of the heat insulating pipe is determined based on the current water content.

In step S102, the control unit 10 reads out one frame of the infrared moving image V _ir from the frame memory (not shown) (processing as the infrared image acquisition unit 11).

In step S103, the control unit 10 reads the reference temperature distribution data from the storage unit 34, compares the reference temperature distribution with the current temperature distribution (infrared moving image V _ir ), and calculates a difference temperature distribution (comparison unit 12). As a process).

FIG. 5 is a diagram showing an example of the reference temperature distribution in the heat insulating pipes P1 to P3. In FIG. 5, the heat insulating pipes P1 and P3 have a uniform temperature distribution. On the other hand, the heat insulation piping P2 is affected by the surrounding temperature environment, and temperature uneven portions D1 and D2 are generated.

FIG. 6 is a diagram showing an example of the temperature distribution after rain (infrared image is V _ir ) in the heat insulating pipes P1 to P3. In FIG. 6, a temperature deviation portion D3 is newly generated as compared with FIG.

FIG. 7 is a diagram showing a differential temperature distribution calculated from the reference temperature distribution (first temperature distribution) shown in FIG. 5 and the temperature distribution after rain (second temperature distribution) shown in FIG. As shown in FIG. 7, a uniform temperature change appears in most of the heat insulating pipes P1 to P3, but only the temperature change in the temperature deviation portion D3 is clearly different from the surrounding temperature change. In other words, it can be estimated that the temperature deviation portion D3 is caused by the inundation of water during rain.

In step S104, the control unit 10 identifies a portion that can be a candidate for a CUI occurrence location (hereinafter referred to as a “CUI candidate location”) (processing as the water content determination unit 13). In the case of FIG. 7, since the temperature deviation portion D3 is considered to be a water-containing portion, which is generated when water is immersed in the heat insulating pipe P2 due to rain, this portion is specified as a CUI candidate location. Note that the CUI candidate location is not limited to one location and may be a plurality of locations.

When trying to specify a CUI candidate location only from the temperature distribution after rainfall shown in FIG. 6, temperature-biased portions D1 and D2 caused by factors other than inundation can also be CUI candidate locations. In the present embodiment, by using the differential temperature distribution (see FIG. 7), changes in the temperature of daytime and nighttime are offset, and the CUI candidate location can be specified reliably. However, since it is conceivable that the water immersed in the heat insulating piping moves, the processing after step S104 is performed in order to increase the detection accuracy.

In step S105, the control unit 10 determines whether or not the position of the identified CUI candidate portion has changed for a predetermined time (for example, 15 minutes) (processing as the water content determination unit 13). When the position of the CUI candidate location has not changed for a predetermined time (“YES” in step S105), the process proceeds to step S106. When the position of the CUI candidate location has not changed but the predetermined time has not elapsed, or when the position of the CUI candidate location has changed before the predetermined time has elapsed ("NO" in step S106), the processing of step S102 is performed. Transition. Moisture that has been immersed in the heat insulation piping due to rain penetrates the heat insulating material from the flooded location and moves to a stable position. In step S105, when the position of the CUI candidate portion does not change for a predetermined time, it is determined that the portion is a portion where moisture remains.

It should be noted that the water immersed in the heat insulating pipe repeatedly evaporates and condenses in the sealed space between the pipe and the exterior material, so that the temperature at the temperature uneven portion is considered to change. However, by appropriately adjusting the cycle for calculating the difference temperature distribution, the CUI candidate location can be specified without causing any other problems.

In step S106, the control unit 10 determines the portion (temperature deviation portion D3 in FIG. 7) tracked as a CUI candidate location as a CUI warning location where moisture is retained and CUI is likely to occur (moisture content determination unit). 13).

In step S107, the control unit 10 determines the water content at the CUI warning location (processing as the water content determination unit 13). The water content includes the water content (the amount of water remaining) and the water content time. That is, the control unit 10 estimates the progress state of the CUI based on the water content and the water content time at the CUI warning location.

For example, it can be estimated that the CUI progresses as the water content increases and the water content time increases. Further, for example, the progress of the CUI may be quantitatively estimated by comparing a value obtained by integrating the water content and the water content time with a predetermined threshold value.

In step S108, the control unit 10 determines whether or not the heat-insulated piping is sound based on the estimated progress of the CUI (processing as the soundness evaluation unit 14). When the heat insulating piping is healthy (“YES” in step S108), the process proceeds to step S101. Until the next rain, the insulated pipe will be continuously evaluated based on the water content of the current CUI warning location. On the other hand, when the heat insulation pipe is not healthy, that is, when it is estimated that corrosion of the heat insulation pipe has progressed significantly and gas leakage is likely to be induced ("NO" in step S108), the process proceeds to step S109.

In step S109, the control unit 10 instructs that repair is required immediately (processing as the soundness evaluation unit 14, see FIG. 8). The worker stops the operation of the plant according to the instruction, disassembles the heat insulating piping, and replaces the parts. Thereby, the gas leak which arises by CUI can be prevented beforehand.

As described above, the pipe evaluation device 1 according to the present embodiment includes the infrared image acquisition unit 11 that acquires the infrared moving image V _ir (infrared image) obtained by imaging the monitoring region including the heat insulating pipes P1 to P3 of the plant, and the infrared ray The first temperature distribution (reference temperature distribution, see FIG. 5) of the heat insulation pipe acquired by the image acquisition unit 11 is compared with the second temperature distribution (see FIG. 6) to generate a differential temperature distribution (see FIG. 6). A comparison unit 13 and a water content determination unit 14 that determines the water content in the heat insulating pipes P1 to P3 based on the difference temperature distribution are provided.

According to the pipe evaluation device 1, it is possible to easily and accurately identify a water-containing portion (CUI warning location) that is likely to be a location where CUI occurs without disassembling the heat-insulated piping P, and soundness of the heat-insulated piping. Can be accurately evaluated. Therefore, reasonable predictive maintenance can be realized.

As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the above-described embodiment, and can be changed without departing from the gist thereof.

For example, the temperature distribution at the time of drying (first temperature distribution) acquired before the rain by the infrared image acquisition unit 11 is compared with the temperature distribution (second temperature distribution) acquired after the rain, and the CUI warning location (CUI) Candidate locations) may be specified. In this case, it is possible to grasp the amount of water increased due to rainfall.

Also, for example, by tracking changes in CUI candidate locations, it is possible to identify the location of inundation in the insulated piping from the state of moisture movement in the insulated piping or the CUI candidate location immediately after rainfall. By repairing the exterior material, it is possible to prevent water from entering the inside of the heat-insulating piping, so that the occurrence of CUI can be suppressed.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

The disclosure of the specification, drawings and abstract contained in the Japanese application of Japanese Patent Application No. 2016-168420 filed on August 30, 2016 is incorporated herein by reference.

1 Pipe Evaluation Device 10 Control Unit 101 CPU
102 ROM
103 RAM
DESCRIPTION OF SYMBOLS 11 Infrared image acquisition part 12 Comparison part 13 Moisture content judgment part 14 Soundness evaluation part 15 Display control part 20 Infrared imaging part 31 Input part 32 Display part 33 Communication part 34 Storage part 341 Reference temperature distribution data

Claims (8)

An infrared image acquisition unit for acquiring an infrared image obtained by photographing a monitoring region including the insulated pipe of the plant;
A comparison unit that compares the first temperature distribution and the second temperature distribution of the heat insulating pipe acquired by the infrared image acquisition unit to generate a differential temperature distribution;
A pipe evaluation apparatus comprising: a water content determination unit that determines a water content in the heat insulating pipe based on the differential temperature distribution. The first temperature distribution is a temperature distribution at the time of drying acquired in advance in the initial operation of the plant by the infrared image acquisition unit,
2. The pipe evaluation device according to claim 1, wherein the second temperature distribution is a temperature distribution after rainfall acquired during operation of the plant by the infrared image acquisition unit. The first temperature distribution is a temperature distribution during drying acquired by the infrared image acquisition unit before rainfall,
The pipe evaluation device according to claim 1, wherein the second temperature distribution is a temperature distribution acquired after rainfall by the infrared image acquisition unit. The said moisture content judgment part specifies the said location as a warning location with high possibility that corrosion will generate | occur | produce, when the location where a temperature change differs from surroundings does not change for a predetermined time. The piping evaluation device described. The pipe evaluation device according to any one of claims 1 to 4, further comprising a soundness evaluation unit that evaluates the soundness of the heat insulation pipe based on a determination result of the water content determination unit. The pipe evaluation device according to claim 5, wherein the soundness evaluation unit determines the progress of corrosion based on a moisture content and a moisture content time at a warning location where corrosion is likely to occur. A first step of acquiring an infrared image obtained by photographing a monitoring region including a heat insulating pipe of the plant;
A second step of generating a differential temperature distribution by comparing the first temperature distribution and the second temperature distribution of the heat insulating pipe obtained by the first step;
A pipe evaluation method comprising: a third step of determining a moisture content in the heat insulating pipe based on the differential temperature distribution. To the computer of the pipe evaluation device to evaluate the soundness of the insulated pipe of the plant,
A first process for acquiring an infrared image obtained by photographing a monitoring region including a heat insulating pipe of the plant;
A second process for generating a differential temperature distribution by comparing the first temperature distribution and the second temperature distribution of the heat insulating pipe obtained by the first process;
A pipe evaluation program for executing a third process for determining a moisture content in the heat insulating pipe based on the difference temperature distribution.

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