JP2007248332A - Lining damage detection method and corrosive fluid housing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily detect damage of the lining of a container with a lining, which houses a corrosive fluid inside, over a long period. <P>SOLUTION: A helical optical fiber sensor 6 is fixed to an external surface of a base material made of metal. The optical fiber sensor 6 measures changes in distortions of the base material made of metal associated with damage in the lining and detects damage in the lining on the basis of the changes in distortions. Distortion changes may be measured by a method for measuring wavelength deviations of light transmitted through the optical fiber sensor at a curved part due to the Doppler effect, a method for measuring changes in the refractive index of the optical fiber sensor; and a method for measuring a distribution of backward scattering light of transmitted light through the optical fiber sensor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for detecting damage to the lining of a container containing corrosive fluid, and a fluid storage device capable of such detection.

  In chemical plants, etc., corrosive liquids such as high-temperature and high-pressure hydrochloric acid, sulfuric acid, and nitric acid are often contained (including storage and transportation). Many structural metal materials cannot be used due to poor corrosion resistance against such corrosive liquids, while glass and ceramic materials are generally said to show good corrosion resistance but are brittle in strength. It is difficult to adopt from the viewpoint of reliability for high-temperature and high-pressure pipes where large thermal stress acts.

  In such a situation, a method is known in which strength is shared by an outer metal base material, and a material excellent in corrosion resistance such as glass or ceramic is coated on the inner surface thereof by coating or lining (patent document). 1 and 2). However, since the thermal expansion coefficient of glass and ceramics is significantly smaller than that of structural metal materials, the coating layer and lining layer may be damaged by cracks and the like due to the thermal stress generated by the difference in thermal expansion coefficient between them. There is a high possibility of causing peeling.

  Once cracking or peeling occurs in the coating layer or lining layer, the corrosive liquid comes into direct contact with the metal base material that is inferior in corrosion resistance, the corrosive liquid leaks in a short time, and the plant shuts down. There are risks. Therefore, a technique for detecting damage to the coating layer and the lining layer due to mechanical or thermal stress quickly and with high accuracy is important.

  Furthermore, such a glass or ceramic lining and coating on the inner surface of a metal member is widely used in the pharmaceutical and food industries that dislike mixing metal elements from the apparatus. Even in such an apparatus, it is necessary to avoid contamination of the metal element into the product due to damage to the lining layer or coating layer, and it is essential to instantaneously detect damage to the lining layer or coating layer from the outside. is there.

  As a typical method for detecting such damage to the coating layer and the lining layer, an ultrasonic flaw detection method and an acoustic emission (AE) method are known. In the ultrasonic flaw detection method, an ultrasonic wave is incident from a metal surface, and a reflected wave at a crack in the coating layer or the lining layer is detected to detect the position and size of the crack. However, since the area that can be detected is narrow, it is impossible to detect unless the position to be damaged is specified in advance and the ultrasonic wave is incident on the position. In addition, when a gap such as peeling occurs between the metal base material and the coating layer or lining layer, the incident ultrasonic wave is reflected on the peeling surface on the metal base material side, and the coating is performed. -It is not possible to detect cracking in the lining layer or lining layer.

The AE method is a method for detecting the sound accompanying damage to the coating layer and the lining layer and detecting the damage, and can cover a wider area than the ultrasonic flaw detection method described above, and There is a high possibility that the coating layer or the lining layer can be sensed at the moment of damage. However, the heat-resistant temperature of the sensor is at most about 300 ° C., and it is not necessarily sufficient in terms of reliability because it is affected by various noises accompanying the operation of the device.
JP 2000-177042 A JP 7-294370 A Japanese Patent Laying-Open No. 2005-300137 JP 2006-38794 A

  In such a situation, in Patent Document 1, the lining layer on the inner surface of the metal base material has a two-layer structure, the surface layer is made of a material having both corrosion resistance and insulation, the base layer is made of a conductive material, and the internal liquid A method for detecting the damage of the lining layer by the electrical change between the metal and the metal base material is proposed. However, it cannot be applied to an insulating liquid such as concentrated sulfuric acid. Moreover, it is difficult to install an electrode in a corrosive liquid for a long time, and there is a problem that the application destination is limited. Furthermore, it is difficult to specify the damage position, and even when damage is detected, it is difficult to repair and replace the damaged part locally, and there is a problem in its maintainability.

  Further, in Patent Document 2, it is necessary to fill a pipe with a conductive liquid medium, and a high-frequency voltage application device is required.

  The present invention has been made in view of the above circumstances, and a method for easily detecting damage to the lining of a container with a lining containing corrosive fluid therein over a long period of time, and corrosivity capable of such detection. An object is to provide a fluid storage device.

  In order to achieve the above object, a lining damage detection method according to the present invention includes a corrosive fluid contained therein, a metal base material, and a material having higher corrosion resistance than the base material against the corrosive fluid. In a lining damage detection method for detecting damage to a lining of a container having a lining, a sensor fixing step of fixing an optical fiber sensor to an outer surface of the metal base material, and the optical fiber sensor accompanying the damage of the lining. A strain change measuring step for measuring a strain change of the metal base material; and a damage detecting step for detecting damage to the lining based on the strain change.

  A corrosive fluid storage device according to the present invention is a corrosive fluid storage device that stores a corrosive fluid therein, and is a metal base material and a material having higher corrosion resistance than the base material with respect to the corrosive fluid. An optical fiber sensor fixed to the outer surface of the metal base material, and strain change measuring means for measuring a strain change of the metal base material accompanying damage to the liner by the optical fiber sensor. It is characterized by having.

  According to the present invention, it is possible to easily detect the damage of the lining of the container with the lining containing the corrosive fluid therein over a long period of time.

  As a result of investigating conventional glass and ceramic lining members, these products are often constructed and fired at high temperatures, and the lining material and metal base material Since the coefficients of thermal expansion differed greatly, it was found that a large residual strain was inherent in both the lining layer and the metal base material during cooling of the manufacturing process.

  Also, the residual strain generated in the lining layer and the residual strain generated in the metal base material are balanced, and if the residual strain in the lining layer is released or disappeared due to damage to the lining layer, the residual metal base material remains. The strain is also released and disappears. As a result, it has been clarified that minute deformation occurs in the metal base material. Therefore, it is possible to detect damage to the coating layer or the lining layer by monitoring the change in strain on the outer surface of the metal base material and detecting the change in strain.

  The heat-resistant optical fiber sensor is stable even at a high temperature of 500 ° C. or higher, and has a characteristic that the wavelength and scattering of light transmitted through the optical fiber changes when the optical fiber is deformed. . Therefore, the optical fiber is fixed to the surface of the metal member subjected to coating or lining, and the coating is detected by detecting a minute strain change on the surface of the metal base material caused by damage to the coating layer or lining layer. It is possible to instantly detect damage to the ting layer and lining layer. Further, by installing this optical fiber sensor independently for each member constituting the equipment such as a pipe and a reaction vessel, for example, the position or member where the coating layer or the lining layer is damaged can be easily identified. And maintainability can be remarkably improved.

  Hereinafter, specific embodiments of a method for detecting damage to a lining in a metal member lined with glass or ceramics according to the present invention and a corrosive fluid storage device will be described with reference to the drawings. Here, the same or similar parts are denoted by common reference numerals, and redundant description is omitted.

[Examples 1 to 3]
Embodiments 1 to 3 of the present invention will be described with reference to FIGS. FIG. 1 is a longitudinal sectional view schematically showing a glass lining pipe 1. A glass lining layer (lining) 5 is provided on the inner surface of the metal pipe base material 4. The metal piping base material 4 is made of, for example, carbon steel, and is lined with glass in order to improve the corrosion resistance of the inner surface. Flange portions 3 are welded to both ends of the straight pipe portion 2 of the glass lining pipe 1.

  The glass lining layer 5 is formed, for example, by heating the metal pipe preform 4 to a high temperature, inserting a glass tube therein, and pressurizing the inside of the glass tube to expand the glass tube, and thereby the inner surface of the metal pipe preform 4. It is formed in close contact with. When cooled to room temperature in such a state, the metal pipe base material 4 having a larger coefficient of thermal expansion has a larger shrinkage, so that a compressive residual strain is generated in the brittle glass lining layer 5 and the structure is difficult to break. On the other hand, tensile residual strain is generated in the metal pipe base material 4 in balance with the compressive residual strain of the glass lining layer 5.

  FIG. 2 schematically shows Examples 1 to 3 of the corrosive fluid container according to the present invention. An optical fiber sensor 6 subjected to a heat treatment is fixed in a spiral shape on the outer peripheral surface of the straight pipe portion 2 of the glass lining pipe 1. The optical fiber sensor 6 is connected to the strain change measuring means 20 and the strain change of the glass lining pipe 1 is measured. Further, the strain change measuring means 20 is connected to a damage detecting means 21 for detecting damage to the lining, and based on the output of the strain change measuring means 20, damage to the glass lining layer 5 (FIG. 1) is detected.

  There are several types of optical fiber sensors 6 depending on the physical quantity to be measured. In Example 1, a method of measuring a wavelength shift at a curved portion due to the Doppler effect of light transmitted through an optical fiber was used. In Example 2, a grating part was provided in the optical fiber, and a method of measuring the shift of the diffraction wavelength in this grating was used (see Patent Document 3, etc.). Example 3 is a method of measuring the distribution of backscattered light transmitted through an optical fiber (see Patent Document 4).

  On the other hand, as shown in FIG. 3, as a comparative example, the surface of the glass lining pipe 1 shown in FIG. 1 is baked with a strain gauge 7 subjected to high temperature treatment (Comparative Example 1), automatic exposure (AE). A device (Comparative Example 2) in which the element 8 was fixed in close contact was manufactured.

  Next, in order to investigate the characteristics of the above detection method, a thermal cycle test was performed. In the heat cycle test, the glass lining pipes shown in Examples 1 to 3 and Comparative Examples 1 and 2 were put in an electric furnace, and after raising the temperature from room temperature to a predetermined temperature, the glass was maintained at the predetermined temperature for 30 minutes. Then, the temperature was lowered to room temperature. At that time, the predetermined temperature to be held was increased from 300 ° C. to 50 ° C., and the test was performed up to a temperature at which the glass lining layer 5 was damaged.

  The results obtained in the thermal cycle test are shown in the table of FIG. In FIG. 4, “○” indicates that the sensor is not damaged (healthy), “×” indicates that the sensor is damaged (cannot be measured thereafter), and “◎” indicates that the lining layer damage is detected. Show.

  From the results of FIG. 4, in Examples 1 to 3 according to the present invention, a change in strain indicating damage of the glass lining layer can be detected at 450 ° C., and strain of the metal base material due to damage of the glass lining layer by this method is detected. It became clear that the change was measurable. On the other hand, in Comparative Example 1 using a strain gauge, the strain gauge was damaged in the first thermal cycle at 300 ° C., and the damage of the glass lining layer at 450 ° C. could not be detected. Also in Comparative Example 2 using the AE sensor, the AE sensor was damaged at 400 ° C., and damage to the glass lining layer at 450 ° C. could not be detected.

  As described above, by using the optical fiber sensors of Examples 1 to 3, it is possible to accurately detect a change in strain on the surface of the metal base material caused by damage to the glass lining layer of the glass lining pipe at a high temperature. Yes, even when a hot corrosive liquid flows inside the pipe, it is possible to instantaneously detect damage to the glass lining layer and prevent leakage to the outside. Moreover, it becomes possible to detect whether the lining layer is damaged at any position by installing the optical fiber sensor spirally over the entire outer periphery of the pipe as in the above embodiment.

[Examples 4 to 7]
Embodiments 4 to 7 of the present invention will be described with reference to FIGS. As shown in Examples 1 to 3 (FIGS. 2 and 3), the optical fiber sensor 6 can be spirally installed on the outer peripheral portion of the glass lining pipe 1 to accurately detect damage to the glass lining layer. It was confirmed. However, the accuracy of the signal measured differs depending on the glass fiber sensor mounting method. For example, when the optical fiber sensor 6 shown in Embodiments 1 to 3 is attached in a spiral shape, information on the entire pipe can be obtained, but the accuracy and sensitivity are slightly lowered.

  That is, the arrangement of the optical fiber sensor shown in FIG. 2 has relatively good sensitivity to changes in the strain in the circumferential direction of the pipe, but the detection sensitivity of strain changes in the longitudinal direction of the pipe is not always sufficient. Further, if the optical fiber sensor is lifted from the metal pipe, the surrounding strain change cannot be measured, and the detection sensitivity may be lowered. Therefore, in this embodiment, in order to improve such a problem, the following configuration is adopted.

  As shown in FIG. 5, in the case of the elbow pipe 9 subjected to glass lining, the curved portion becomes stress concentrated, and the possibility that the glass lining layer is damaged at the same position is very high. In order to cope with this, the following configuration is adopted.

  In Example 4, as shown in FIG. 5, the optical fiber sensor 6 was concentratedly wound around the curved portion.

  In Example 5, as shown in FIG. 6, the optical fiber sensor was spirally installed on the outer side and the inner side of the curved portion that tends to become a stress concentration portion. This is because in Example 4, the strain detection sensitivity in the longitudinal direction of the pipe is low.

  In Example 6, as shown in FIG. 7, the optical fiber sensor is an elliptical spiral optical fiber sensor 6b, and the elliptical long axis direction is set in accordance with the circumferential direction that requires favorable sensitivity. This is because the straight pipe portion 2 subjected to the glass lining has a large strain change in the circumferential direction due to the damage of the glass lining layer, but the strain change in the longitudinal direction may be large in the fracture mode.

  In Example 7, as shown in FIG. 8, in addition to the elliptical spiral optical fiber sensor 6b of Example 6, an elliptical spiral optical fiber in which the major axis direction of the elliptical shape is matched with the longitudinal direction of the pipe. A sensor 6c was also installed.

  In addition to the above Examples 4-7, thermal cycle tests were conducted as Comparative Example 3 and Comparative Example 4, respectively, in which the optical fiber sensors were spirally arranged over the entire elbow pipe 9 and the straight pipe part 2.

  In the thermal cycle test, for elbow pipes and straight pipes, a compressive load is applied in the vicinity of the center of the pipe and a strain is forced in the circumferential direction, and a compressive load is applied to the flanges at both ends. This was carried out in the case where a longitudinal strain was forcibly applied. The thermal cycle test was carried out for three elbow pipes and three straight pipes, and ended when any of the optical fiber sensors detected damage to the glass lining layer.

  The experimental results of Examples 4 and 5 and Comparative Example 3 using elbow piping are shown in the table of FIG. In FIG. 9, when the damage of the glass lining layer can be detected, “◯” is indicated, and when it is not detected, “X” is indicated.

  From the experimental results shown in FIG. 9, in Comparative Example 3 in which the optical fiber sensor was installed over the entire elbow pipe, the detection sensitivity in the circumferential direction was relatively good, but the optical fiber sensor was installed concentrated on the stress concentration part. In Example 4, it was possible to capture a minute strain change that could not be detected in Comparative Example 3, and it was confirmed that the circumferential detection sensitivity was improved. On the other hand, it can be seen that Example 5 in which the optical fiber sensors are arranged in a spiral shape can satisfactorily capture the longitudinal strain change that could not be detected in Example 4 and Comparative Example 3.

  Next, the experimental results of Examples 6 and 7 and Comparative Example 4 using a straight pipe are shown in the table of FIG. As in FIG. 9, when the damage of the glass lining layer can be detected, “◯” is indicated, and when it is not detected, “X” is indicated.

  From the experimental results shown in FIG. 10, in Comparative Example 4 in which the optical fiber sensor is installed over the entire straight pipe, the circumferential detection sensitivity is good, but by installing the optical fiber sensor in an elliptical spiral shape, It can be seen that the detection sensitivity in the longitudinal direction in addition to the direction is significantly improved. Further, it is clear that Example 7 in which such elliptical spiral sensors are installed in directions in which the respective long axes are orthogonal shows excellent detection sensitivity in both the circumferential direction and the longitudinal direction.

  As described above, by optimizing the installation position and installation shape of the optical fiber sensor, detection sensitivity suitable for each product can be obtained.

  Such residual strain between the metal base material and the lining layer is generated not only in the piping but also in any member, and the strain change of the metal base material due to the damage of the lining layer is detected using an optical fiber sensor. By detecting it, it becomes possible to detect the damage of the lining layer instantly and accurately.

The longitudinal cross-sectional view which shows an example of the glass lining piping which concerns on this invention. The typical external view which shows Examples 1-3 of the corrosive fluid accommodation apparatus which concerns on this invention. The typical external view which shows the comparative examples 1 and 2 of the corrosive fluid accommodating apparatus which concerns on this invention. The table | surface which shows the experimental result of Examples 1-3 and Comparative Examples 1 and 2 of the corrosive fluid accommodation apparatus which concerns on this invention. The typical external view which shows Example 4 of the corrosive fluid accommodating apparatus which concerns on this invention. The typical external view which shows Example 5 of the corrosive fluid accommodating apparatus which concerns on this invention. The typical external view which shows Example 6 of the corrosive fluid accommodating apparatus which concerns on this invention. The typical external view which shows Example 7 of the corrosive fluid accommodating apparatus which concerns on this invention. The table | surface which shows the experimental result of Examples 4 and 5 and the comparative example 3 of the corrosive fluid accommodation apparatus which concerns on this invention. The table | surface which shows the experimental result of Examples 6 and 7 and the comparative example 4 of the corrosive fluid accommodation apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Glass lining piping 2 ... Straight pipe part 3 ... Flange part 4 ... Metal piping base material (metal base material)
5 ... Lining layer (lining)
6, 6a, 6b, 6c ... optical fiber sensor 7 ... strain gauge 8 ... AE sensor 20 ... strain change measuring means 21 ... damage detecting means

Claims (10)

In a lining damage detection method for containing a corrosive fluid inside and detecting damage to a lining of a container having a metal base material and a lining of a material having higher corrosion resistance than the base material against the corrosive fluid,
A sensor fixing step of fixing an optical fiber sensor to the outer surface of the metal base material;
A strain change measuring step of measuring a strain change of the metal base material due to damage of the lining by the optical fiber sensor;
A damage detection step of detecting damage to the lining based on the strain change;
A lining damage detection method characterized by comprising:   2. The lining damage detection method according to claim 1, wherein the strain change measurement step includes a step of measuring a wavelength shift of the curved portion due to the Doppler effect by the light transmitted through the optical fiber sensor.   The lining damage detection method according to claim 1, wherein the strain change measurement step includes a step of measuring a change in refractive index of the optical fiber sensor.   The lining damage detection method according to claim 1, wherein the strain change measurement step includes a step of measuring a transmitted light backscattered light distribution of the optical fiber sensor.   5. The container according to any one of claims 1 to 4, wherein the container is tubular, and the optical fiber sensor is spirally installed over substantially the entire longitudinal direction of the container in the sensor fixing step. The lining damage detection method as described.   The lining damage detection method according to any one of claims 1 to 4, wherein in the sensor fixing step, the optical fiber sensor is installed in a stress concentration portion of the container.   The lining damage detection method according to claim 1, wherein the optical fiber sensor is installed in a spiral shape in the sensor fixing step.   The lining damage detection method according to claim 7, wherein the optical fiber sensor has an elliptical shape having an aspect ratio.   9. The lining damage according to claim 8, wherein in the sensor fixing step, a plurality of elliptical spiral optical fiber sensors are installed on the outer surface of the container so that the longitudinal axis directions thereof are orthogonal to each other. Detection method. A corrosive fluid containing device for containing a corrosive fluid inside,
A metal base material,
A lining of a material having higher corrosion resistance than the base material against the corrosive fluid;
An optical fiber sensor fixed to the outer surface of the metal base material;
A strain change measuring means for measuring a strain change of the metal base material due to damage of the lining by the optical fiber sensor;
A corrosive fluid containing device characterized by comprising:

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