Method for detecting sulfide corrosion sites, device for detecting sulfide corrosion sites, and fluorescent substance or phosphorescent substance for detecting sulfide corrosion sites

Abstract

To provide a method, a device, and a fluorescent material or a phosphor for detecting sulfidation corrosion sites, which enable detection of sulfidation corrosion sites over a wide range.SOLUTION: Ash 11 on a surface of a boiler heat transfer tube 10 is irradiated with ultraviolet light, and a covered site 13 covered with a fluorescent part 12 of the ash is determined to have sulfidation corrosion if the fluorescence emitted from the florescent part 12 of the ash 11 has a first peak wavelength in a wavelength range of 500-550 nm, inclusive.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a detection method and a detection device for detecting a site where sulfide corrosion will occur or a site where sulfide corrosion has already occurred in a metal member used in a heat transfer tube of a coal-burning boiler or gasifier, etc. The present invention also relates to a fluorescent substance or phosphorescent substance for detecting a site where sulfide corrosion will occur or a site where sulfide corrosion has already occurred, which can detect a site where sulfide corrosion will occur or a site where sulfide corrosion has already occurred. [Background technology]

[0002] In recent years, two-stage combustion has been adopted in thermal power plants that burn pulverized coal, with the aim of achieving low NOx operation from the perspective of environmental considerations. It is known that low NOx operation causes sulfidation corrosion of boiler heat transfer tubes due to reducing combustion gases. Patent Document 1 discloses that ZnS (zinc sulfide) is concentrated in the ash that adheres to the sulfidation-corroded areas.

[0003] The concentrations of Zn and S contained in ash can be measured using elemental analysis methods such as EPMA and XRF. Zn and S do not necessarily exist as ZnS (for example, S can exist as PbS), but if Zn is present in a significant concentration, it may exist as ZnS and cause sulfidation corrosion. Therefore, by measuring the Zn concentration in ash collected from the boiler or in ash that remains attached to the boiler, it can be determined that areas of the heat transfer tube where ash containing high concentrations of Zn has adhered are areas where sulfidation corrosion is occurring.

[0004] Because elemental analysis methods are applied to measurement points on ash that has adhered widely to heat transfer tubes, they are not efficient for measuring Zn concentrations over a wide area. Furthermore, it is unclear whether the concentration measured is the maximum value or average value around the measurement point. To address these issues, measuring Zn concentrations at multiple measurement points is an option. However, this method still requires measurements at each measurement point, and it cannot be said to be efficient for comprehensively measuring Zn concentrations over a wide area. Another option is for an experienced technician to identify areas suspected of sulfide corrosion and then perform measurements at those locations. However, this method relies on human experience and lacks reliability.

[0005] This problem exists not only when the object to be detected for sulfidation corrosion is a heat transfer tube of a boiler or gasification furnace in a thermal power plant that burns pulverized coal, but also when the object is a metal component with deposits on its surface. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-2551 [Non-patent literature]

[0007] [Non-Patent Document 1] Shuji Mori, Satoru Kakitani, Hiroshi Miyake, Kazuhiro Yamaguchi, Phase transition and fluorescence spectrum in the Zn2SiO2-Mn2Si04 system, 1994, Bulletin of Okayama University of Science. A, Natural Sciences, 30, 115-120(1994), http: / / id.nii.ac.jp / 1182 / 00001100 / [Non-patent document 2] Wentao Zhang, Hong-Ro Lee, Synthesis and luminescence properties of Zn(Cu(0.01) Cd(0.02) Mg(0.02))S phosphor, April 12, 2011, The journal of biological and chemical luminescence, https: / / doi.org / 10.1002 / bio.1190 [Non-patent document 3] Tatsuya Ueda, Synthesis of Mn-doped ZnS nanoparticles using a solution method and fabrication of EL devices, March 2012, Master's thesis, Faculty of Engineering, Gunma University, http: / / hdl.handle.net / 10087 / 8502 [Non-patent document 4] Tetsuhiko Isobe, High Luminescence Efficiency of Doped Nanocrystals by Silica Surface Modification, July 19, 2011, Journal of the Illuminating Engineering Institute of Japan, Vol. 87, No. 4, 2003, pp. 256-261, https: / / doi.org / 10.2150 / jieij1980.87.4_256 [Non-patent document 5] Tetsuhiko Isobe, Luminescence Mechanism and Local Structure Analysis of Organic / Inorganic Hybrid ZnS:Mn Nanocrystal Phosphors, October 27, 2007, Surface Science Vol. 22, No. 5, pp. 315-322, 2001, https: / / doi.org / 10.1380 / jsssj.22.315 [Non-patent document 6] Ginya Adachi, Phosphors used in color television cathode ray tubes (<Special Issue> Progress in Display Materials), August 20, 1990, Chemistry and Education 1990, Vol. 38, No. 4, pp. 386-390, https: / / doi.org / 10.20665 / kakyoshi.38.4_386 [Non-Patent Document 7] Wageh, S., Ternary ZnS:Te nanoparticles capped with 3-mercaptopropionic acid prepared in aqueous media,2016, Journal of Materials Science: Materials in Electronics; 27, 10; 10877-10887; 2016, https: / / doi.org / 10.1007 / s10854-016-5197-7 [Non-patent document 8] Masashi Shirata, "Study on the creation and luminescence properties of novel zinc sulfide phosphors activated with iridium and related metals," Shizuoka University, Doctoral dissertation, (2011). http: / / doi.org / 10.14945 / 00006522 [Non-Patent Document 9] Kotera Yoshihide, Naraoka Kiyotaka, Electrophotoluminescence of Zinc Sulfide Phosphors, April 12, 2006, Bulletin of the Chemical Society of Japan Vol.33, Issue 6, https: / / doi.org / 10.1246 / bcsj.33.721 [Non-Patent Document 10] Srinivasa Buddhudu, Hong Xi Zhang, Chan Hin Kam, Seng Lee Ng, Boon Siew Ooi, Yee Loy Lam, Yuen Chuen Chan, Yan Zhou, Wenxiu Que, Terence Kin Shun Wong,Green and red luminescence in Tb3+ and Eu3+:Zn2SiO4 powders, April 13, 2000, Proceedings Volume 3942, Rare-Earth-Doped Materials and Devices IV; (2000), https: / / doi.org / 10.1117 / 12.382881 [Non-Patent Document 11] Koji Inoue, Minetomo Masuda, Fabrication of thin films of wide bandgap ZnO phosphors by cation doping, 2011, Mie Prefectural Industrial Research Institute Research Report (36), 1-4, 2011, https: / / www.pref.mie.lg.jp / common / content / 000172058.pdf [Non-Patent Document 12] Yang Li, Yiyang Li, Ruchun Chen, Kaniyarakkal Sharafudeen, Shifeng Zhou, Mindaugas Gecevicius, Haihui Wang, Guoping Dong, Yiling Wu, Xixi Qin and Jianrong Qiu, Tailoring of the trap distribution and crystal field in Cr3+-doped non-gallate phosphors with near-infrared long-persistence phosphorescence, May 22, 2015, NPG Asia Materials volume 7, page 180(2015), https: / / doi.org / 10.1038 / am.2015.38 [Non-Patent Document 13] Dongqiang Han, Low-temperature synthesis and photoluminescence properties of oriented ZnAl2O4 nanowire arrays, August 4, 2017, Superlattices and Microstructures Volume 111, November 2017, Pages 1093-1098, https: / / doi.org / 10.1016 / j.spmi.2017.08.012 Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above circumstances, a main object of the present invention is to provide a method and an apparatus for detecting sulfide-corroded areas that can detect sulfide-corroded areas over a wide range. Another object of the present invention is to provide a fluorescent substance or a phosphorescent substance for detecting sulfide-corroded areas that can detect corroded areas. [Means for solving the problem]

[0009] In the present invention, "sulfide corrosion occurs or has occurred in a part of the member (hereinafter referred to as the coated part) covered by the luminescent part of the attachment (hereinafter referred to as the luminescent part)" means that sulfide corrosion has not yet occurred in the coated part but there is a possibility that sulfide corrosion will occur in the future, or that sulfide corrosion has already occurred.

[0010] In the present invention, the light emitted from the light-emitting site is fluorescence or phosphorescence. In the following description, the term "fluorescence" means fluorescence or phosphorescence. Similarly, "fluorescent material" means fluorescent material or phosphorescent material.

[0011] The present invention can detect sulfidation corrosion in any metal component, such as a boiler that burns pulverized coal or a heat transfer tube in a gasifier that gasifies and burns coal.

[0012] An aspect of the present invention for achieving the above object is a method for detecting a sulfide-corroded area, which comprises irradiating ultraviolet light onto an attachment attached to the surface of a metal member, and determining that sulfide corrosion has occurred or is occurring in a coated area of ​​the member that is covered by the light-emitting area of ​​the attachment if the fluorescence emitted from the attachment includes a first peak wavelength in a wavelength band of 500 nm or more and 550 nm or less.

[0013] Another aspect of the present invention for achieving the above object is a detection device for a sulfide-corroded area, comprising: an ultraviolet light source that irradiates ultraviolet light onto an attachment attached to the surface of a metal member; a spectroscopic measurement unit that measures the spectroscopic spectrum of the fluorescence emitted from the attachment; and a determination unit that determines that sulfide corrosion has occurred in a covered area of ​​the member that is covered by the light-emitting part of the attachment if the spectroscopic spectrum includes a first peak wavelength of 500 nm or more and 550 nm or less.

[0014] Another aspect of the present invention for achieving the above object is a phosphor for detecting sulfide corrosion sites or a phosphor for detecting sulfide corrosion sites, which comprises a zinc compound containing Zn as a main component and at least one member selected from the group consisting of Mn, Cu, Cd, Ag, Au, Cl, Ir, Te, Fe, Pb, Tb, Eu, Mg, and Cr, and which is excited by ultraviolet light to emit fluorescence having a first peak wavelength in a wavelength band of 500 nm or more and 550 nm or less, and which is formed on the surface of a metal member.

[0015] Another aspect of the present invention for achieving the above object resides in a phosphor for detecting sulfide corrosion sites, which contains ZnAl2O4 or ZnMgO as a zinc compound containing Zn as a main component, is excited by ultraviolet light to emit fluorescence having a first peak wavelength in a wavelength band of 500 nm or more and 550 nm or less, and is formed on the surface of a metal member. [Effects of the Invention]

[0016] According to the present invention, there are provided a method and an apparatus for detecting sulfide-corroded portions, which are capable of detecting sulfide-corroded portions over a wide area, and a phosphor for detecting sulfide-corroded portions, which is capable of detecting corroded portions. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram of a detection device for a sulfide corrosion site. [Figure 2] 1A and 1B are a plan view and a cross-sectional view illustrating light emitted from ash attached to a heat transfer tube. [Figure 3] FIG. 1 is a diagram showing the results of EPMA analysis. [Figure 4] FIG. [Figure 5] 1 is a photograph showing a sample that emits orange fluorescence. DETAILED DESCRIPTION OF THE INVENTION

[0018] The method and device for detecting sulfide corrosion according to an embodiment of the present invention will be described with reference to the drawings. In addition, to supplement the explanation of colors and color development, color drawings corresponding to Figures 3 to 5 are attached to the application form and submitted.

[0019] In this embodiment, a case will be described in which it is determined whether sulfidation corrosion has occurred or has occurred in heat transfer tubes of a boiler that burns coal or a gasifier that gasifies and burns coal.

[0020] Figure 1 is a schematic diagram of a detection device for sulfide corrosion sites. Figure 2(a) is a plan view illustrating the light emitted from ash attached to a heat transfer tube, and Figure 2(b) is a cross-sectional view taken along line AA. As shown in Fig. 1, the detection device 1 is used to detect sulfidation corrosion sites that have occurred on a boiler heat transfer tube 10 (an example of a component recited in the claims). Ash 11 (an example of an attachment recited in the claims) adheres to the heat transfer tube 10 as a result of the combustion of pulverized coal.

[0021] The detection device 1 includes an ultraviolet light source 2, a camera 3, and a determination unit 4. The ultraviolet light source 2 may be a device equipped with an ultraviolet LED that emits ultraviolet light, or a device configured to extract ultraviolet light by applying a bandpass filter to a xenon mercury lamp. The wavelength of the ultraviolet light is not particularly limited, as long as it has a peak in the wavelength range of 200 nm to 430 nm. Wavelengths from 200 nm to 400 nm are ultraviolet light, and wavelengths around 430 nm are violet light. As described below, it is assumed that even violet light with wavelengths longer than ultraviolet light can produce fluorescence, so an ultraviolet light source capable of emitting ultraviolet to violet light can be used. Hereinafter, "ultraviolet light" is defined as "ultraviolet light or violet light having a peak in the wavelength range of 200 nm to 430 nm." The camera 3 measures the spectrum of the received light and is an example of a spectroscopic measurement unit described in the claims. Other spectroscopic measurement units that can be used include a spectrometer, a camera equipped with a bandpass filter, and a photodetector equipped with a bandpass filter. The determination unit 4, the details of which will be described later, is an information processing device that analyzes the spectroscopic spectrum and detects the sulfide corrosion site.

[0022] The method for detecting sulfide corrosion sites on the heat transfer tubes 10 of a boiler is carried out as follows. During a regular inspection, an ultraviolet light source 2 is brought into the boiler, and as shown in Figure 2, the ultraviolet light source 2 is made to irradiate any location on the heat transfer tube 10 with ultraviolet light. The ultraviolet light may be irradiated without touching the heat transfer tube 10, or the ash 11 may be wiped away to a certain extent before the ultraviolet light is irradiated. When the ultraviolet light is irradiated, orange fluorescence can be seen from part of the ash 11.

[0023] The fluorescence, as will be described in detail later, has a first peak wavelength in the wavelength band of 500 nm or more and 550 nm or less. The fluorescence also has a second peak wavelength in the wavelength band of 600 nm or more and 700 nm or less. Fluorescence of such wavelengths can be seen as orange from the light-emitting site 12. Note that "visible from the light-emitting site 12" here does not only refer to the case where the fluorescence can be seen from the light-emitting site 12 exposed after the ash 11 has been removed, but also includes the case where the light-emitting site 12 is covered to some extent by the ash 11 and the fluorescence can be seen from the light-emitting site 12 even through the ash 11.

[0024] If fluorescence from such a light-emitting portion 12 can be visually recognized, it is determined that the part of the heat transfer tube 10 covered by the light-emitting portion 12 (hereinafter referred to as the covered portion 13) is a portion where sulfide corrosion has occurred in a dented shape. The light emitted from the light-emitting portion 12 is considered to be fluorescence or phosphorescence.

[0025] The detection method of the present invention is not limited to irradiating ultraviolet light onto the ash 11 adhering to the heat transfer tube 10. It is also possible to collect ash 11 from the heat transfer tube 10 and irradiate the collected ash 11 with ultraviolet light. If a light-emitting portion 12 can be visually confirmed in the ash 11 after irradiation with ultraviolet light, it is determined that sulfide corrosion has occurred in the coated portion 13 of the heat transfer tube 10 where the ash 11 was adhering.

[0026] Here, we will explain the composition of the luminous region. Ash attached to the heat transfer tubes of a boiler that burns coal in actual operation was irradiated with ultraviolet light, and the luminous region that was visually confirmed to be emitting light from the ash was collected and used as a sample. Elemental analysis of the sample was performed using an electron probe microanalyzer (hereinafter referred to as EPMA). The results are shown in Figure 3. The figure shows an image in which each element is color-coded according to its concentration. Zn and S are shown in pink, indicating high concentrations, within the dotted oval. In other words, the EPMA results revealed that high concentrations of Zn and S were present in the luminous region.

[0027] The sample used was ash adhering to the heat transfer tubes of a coal-fired boiler. This sample was irradiated with ultraviolet light, and the fluorescence emitted by the ultraviolet light was received by camera 3 to obtain a spectrum. The fluorescence was visually recognized as orange. The ultraviolet light was obtained by applying a bandpass filter that transmits ultraviolet light to a xenon mercury lamp. The bandpass filter was a HOYA U340 bandpass filter. The results are shown in Figure 4.

[0028] Figure 4(a) shows the spectrum of the excitation light source (ultraviolet light), and Figure 4(b) shows the spectrum of the fluorescence obtained from the sample. The horizontal axis is wavelength, and the vertical axis is emission intensity.

[0029] As shown in Figure 4(a), the ultraviolet light spectrum UV has a peak in the wavelength range from 200 nm to 430 nm. A peak is also seen in the wavelength range from 650 nm to 800 nm, which is probably due to reflection from the sample.

[0030] As shown in Figure 4(b), the spectrum Fo of the orange fluorescence emitted from the sample had a first peak in the wavelength range of 500 nm to 550 nm and extended over the wavelength range of 460 nm to 700 nm. This suggests that the sample may contain a substance that emits fluorescence with the first peak. Furthermore, peaks were observed before and after the first peak, which were similar to the spectrum of ultraviolet light and therefore were considered to be the spectrum of ultraviolet light.

[0031] Furthermore, the intensity gradient of the spectrum Fo changed in the wavelength range from 600 nm to 700 nm, which suggests that the sample may contain a substance that emits fluorescence with a peak (hereinafter referred to as the second peak) in this wavelength range.

[0032] Non-Patent Document 1 discloses that (Zn-Mn)2SiO4 emits light having a spectrum similar to that of spectrum Fo shown in FIG. 4 and a first peak similar to that of spectrum Fo. Non-Patent Document 2 discloses that Zn(Cu,Cd,Mg)S emits light having a first peak similar to that of spectrum Fo shown in FIG. 4. Non-Patent Documents 3 to 5 disclose that ZnS:Mn emits fluorescence having a peak near 600 nm. Non-Patent Document 6 discloses that ZnS:Ag emits fluorescence having a peak at 465 nm and ZnS:Au,Cu,Al emits fluorescence having a peak at 539 nm. Non-Patent Document 7 discloses that ZnS:Te emits fluorescence having a peak at 439 nm. Non-Patent Document 8 discloses that ZnS:Cl and ZnS:Cl,Ir emit fluorescence having peaks at 440 to 450 nm and 515 nm, respectively. Non-Patent Document 9 describes that ZnS:Ag, (Zn,Cd)S:Ag, ZnS:Cu, (ZnCd)S:Cu, ZnS:CuFe, ZnS:Cu,Pb, ZnS:Pb,Mn, ZnS:Mn, ZnS, ZnO:Mn, (Zn,Cd)S:Mn, Zn(S,Se):Cu emit light. Non-Patent Document 10 describes that Tb 3+ Zn2SiO4 emits fluorescence with a peak at 543 nm, and Eu 3+ It is described that Zn2SiO4 emits fluorescence with a peak at 612 nm. Non-patent document 11 describes that ZnMgO emits fluorescence with a peak at 400 nm to 500 nm. Since Mg is contained at 10% or more, it is considered to be a major component rather than a trace element. Non-patent document 12 describes that Zn2SnO4:Cr and Zn (2-x) Al2xSn (1-x) It is described that O4:Cr emits fluorescence with a peak at 800 nm in the wavelength range from 650 nm to 1200 nm. Non-Patent Document 13 describes that ZnAl2O4 emits light centered at 500 nm.

[0033] Table 1 shows the luminescent materials described in the above-mentioned non-patent documents, as well as their main components and trace elements. [Table 1]

[0034] To summarize the above results, the EPMA results showed that the material constituting the light-emitting portion 12 contained a high concentration of Zn, and therefore it was considered to be a material whose main component was Zn. Furthermore, Patent Document 1 describes that ZnS has an effect on sulfide corrosion, and based on a comparison of the spectroscopic spectrum with Non-Patent Documents 1 to 13, it was considered that the material was mainly composed of a zinc compound. The zinc compound is at least one selected from the group consisting of ZnS, ZnCdS, Zn(S,Se), and zinc oxide. The zinc oxide is Zn2SiO4, ZnO, ZnMgO, Zn2SnO4, Zn (2-x) Al 2x Sn (1-x) The element is at least one selected from the group consisting of Tb, Eu, and ZnAl2O4. Furthermore, Tb and Eu, as described in Non-Patent Document 10, emit light when contained as trace substances in Zn2SiO4. However, it is not clear from each Non-Patent Document whether they also emit light when contained in a main component other than Zn2SiO4 (for example, ZnS). However, it was presumed that they would emit light even when contained in other main components. Similarly, it was presumed that trace elements other than Tb and Eu would also emit light when contained in the main components listed in Table 1.

[0035] Based on a comparison of the spectroscopic spectra and Non-Patent Documents 1 to 13, it is believed that trace elements (e.g., Mn, Cu, Cd, Ag, Au, Cl, Ir, Te, Fe, Pb, Tb, Eu, Mg, Cr) may contribute to the fluorescence emission, with Mn and Cu being particularly likely to contribute. Furthermore, it is believed that ZnAl2O4 and ZnMgO may emit light even without containing trace elements.

[0036] Therefore, it was presumed that the luminescent site 12 (fluorescent substance or phosphor for detecting sulfide corrosion sites) contains a zinc compound and at least one trace element selected from the group consisting of Mn, Cu, Cd, Ag, Au, Cl, Ir, Te, Fe, Pb, Tb, Eu, Mg, and Cr. Alternatively, it was presumed that the luminescent site 12 is ZnAl2O4 or ZnMgO, which is a zinc compound.

[0037] It is generally known that excitation becomes stronger as the excitation wavelength becomes shorter. For example, using deep-ultraviolet light around 200 nm strengthens excitation and increases the intensity of emission. However, as shown in Figure 4, it has been found that samples can emit sufficient fluorescence even with ultraviolet light around 400 nm or violet light around 430 nm, which are not deep-ultraviolet light. Deep-ultraviolet light can be obtained using a xenon mercury lamp, but this tends to require a large-scale device configuration. On the other hand, ultraviolet light around 400 nm and violet light around 430 nm can also be obtained with ultraviolet LEDs. For this reason, ultraviolet LEDs, which are cost-effective and portable, can be used as an ultraviolet light source to excite samples.

[0038] Figure 5 shows an example of the fluorescence emitted from the sample. Figure 5 is a photograph showing a sample emitting orange fluorescence. The sample in Figure 5 is ash adhering to the surface of a boiler extruded tube material, and the surface of the sample that was in contact with the heat transfer tube 10 is shown.

[0039] Figure 5(a) shows the sample before it was irradiated with ultraviolet light, and Figure 5(b) shows the sample after it was irradiated with ultraviolet light. The oval in the photograph indicates the area that glows orange. As shown in the figure, before ultraviolet light was irradiated, the area indicated by the oval was indistinguishable from the area outside of that area. On the other hand, when ultraviolet light was irradiated onto the sample, an area that glowed orange could be seen within the purple irradiated area indicated by the oval. Furthermore, sulfide corrosion had occurred in a part (coated area 13 in Figure 2) of the base material (heat transfer tube 10 in Figure 2) covered by this orange-emitting area (light-emitting area 12 in Figure 2).

[0040] As described above, the method for detecting a sulfide corrosion site of the present invention irradiates ultraviolet light onto ash 11 attached to the surface of a heat transfer tube 10, and if the fluorescence emitted from the ash 11 is visually recognized as orange, that is, if the fluorescence has a first peak wavelength in the wavelength band of 500 nm or more and 550 nm or less, it is determined that sulfide corrosion has occurred or is occurring in the coated site 13 covered with ash 11.

[0041] Thus, by irradiating the heat transfer tube 10 with ultraviolet light and observing the fluorescence emitted from the ash 11, it is possible to detect areas where sulfide corrosion has occurred or where there is a high risk of sulfide corrosion progressing in the future. Conventionally, sulfide corrosion areas have been identified by targeting measurement points. However, in the detection method of the present invention, ultraviolet light is irradiated over a certain area of ​​the surface of the heat transfer tube 10, allowing sulfide corrosion areas to be detected on a surface-by-surface basis. Therefore, sulfide corrosion areas can be detected more efficiently than conventional methods. Furthermore, because sulfide corrosion areas are detected on a surface-by-surface basis, it is possible to solve the conventional problem of not being able to determine whether the ZnS concentration in the sulfide-corroded area is the maximum value or the average value. Furthermore, because sulfide corrosion areas are detected based on the visual observation of the fluorescence emitted from the ash 11, it can be performed reliably without relying on the experience of a skilled worker.

[0042] Furthermore, if the fluorescence includes a first peak wavelength in the wavelength band of 500 nm or more and 550 nm or less, and further includes a second peak wavelength in the wavelength band of 600 nm or more and 700 nm or less, it is determined that sulfide corrosion has occurred in the coated portion 13 covered with ash 11. This makes it possible to determine that sulfide corrosion has occurred or is occurring in the coated portion 13 covered with ash 11.

[0043] Orange fluorescence having the above-mentioned wavelength can be seen by irradiating ultraviolet light onto ash 11 that remains attached to heat transfer tube 10 or onto ash 11 that has been partially wiped off. Therefore, compared to completely removing ash 11 and directly checking for sulfide corrosion on heat transfer tube 10, the effort required to remove ash 11 can be saved, and the location of sulfide corrosion can be identified in a shorter time.

[0044] Furthermore, sulfide corrosion may be detected not only by visually observing the fluorescence with the naked eye, but also by analyzing the spectral spectrum. An example of such a device configuration is the detection device 1, as shown in FIG. 1, which includes an ultraviolet light source 2, a camera 3, and a determination unit 4. The determination unit 4 is an information processing device that analyzes the spectral spectrum measured by the camera 3. Specifically, if the spectral spectrum includes a first peak wavelength in the wavelength range of 500 nm to 550 nm, the determination unit 4 determines that sulfide corrosion has occurred in the coated portion 13 of the heat transfer tube 10 covered by the light-emitting portion 12 emitted by the ash 11. Furthermore, if the spectral spectrum includes a second peak wavelength in the wavelength range of 600 nm to 700 nm, the determination unit 4 determines that sulfide corrosion has occurred in the coated portion 13 of the heat transfer tube 10 covered by the light-emitting portion 12 emitted by the ash 11. This detection device 1 provides the same effects as the above-described detection method.

[0045] The light-emitting portion 12 (hereinafter also referred to as a sulfide corrosion site detection phosphor) includes a zinc compound primarily composed of Zn and at least one element selected from the group consisting of Mn, Cu, Cd, Ag, Au, Cl, Ir, Te, Fe, Pb, Tb, Eu, Mg, and Cr, and is excited by ultraviolet light to emit fluorescence having a first peak wavelength in a wavelength band of 500 nm to 550 nm. Because the sulfide corrosion site detection phosphor emits the above fluorescence in response to ultraviolet light, it can be used to detect sulfide corrosion sites in the coating portion 13 on which the sulfide corrosion site detection phosphor is formed. A sulfide corrosion site detection phosphor that includes ZnAl2O4 or ZnMgO, which is a zinc compound primarily composed of Zn, and that is excited by ultraviolet light to emit fluorescence having a first peak wavelength in a wavelength band of 500 nm to 550 nm can also be used to detect sulfide corrosion sites.

[0046] In particular, in the detection device configured to mount an ultraviolet light source 2 and a camera 3 on a drone, which will be described later, there is no need for a device configuration for removing ash 11, thereby reducing costs, and furthermore, the method can be performed in a shorter time than the method of determining sulfide corrosion areas that involves removing ash 11.

[0047] The above describes one embodiment of the present invention. However, the present invention is not limited to the above embodiment, and additions, omissions, substitutions, and other modifications of the configuration are possible within the scope of the spirit of the present invention.

[0048] In the above embodiment, the case of detecting sulfide corrosion in a heat transfer tube of a boiler has been described, but the present invention is not limited to this example. The present invention can also be applied to any metal member and any deposits attached to the surface of the member.

[0049] Furthermore, the spectroscopic measurement unit, such as an ultraviolet light source and a camera, may be mounted on a drone. For example, the ultraviolet light source and camera may be mounted on a drone, and the drone may be flown inside the boiler while irradiating the heat transfer tube with ultraviolet light and capturing the fluorescence with the camera. The obtained spectrum may be stored in a storage device mounted on the drone, or transmitted to a monitor or determination unit separate from the drone via wireless communication means mounted on the drone. Of course, a determination unit composed of a microcomputer or the like may be mounted on the drone to determine the presence of sulfide corrosion on the spot. Such a drone-type detection device or a detection method using the detection device can easily irradiate ultraviolet light and measure fluorescence on a portion located at a high position in the boiler. [Explanation of symbols]

[0050] 1...detection device, 2...ultraviolet light source, 3...camera, 4...determination unit

Claims

1. UV light is irradiated onto the deposits on the surface of the metal member, When the fluorescence emitted from the attachment includes a first peak wavelength in a wavelength band of 500 nm or more and 550 nm or less, it is determined that sulfide corrosion has occurred or is occurring in the coated portion of the component that is covered by the light-emitting portion of the attachment, the member is a heat transfer tube of a boiler that burns fuel in a reducing atmosphere, The deposit is ash that has adhered to the heat transfer tube. A method for detecting a sulfide corrosion site, comprising:

2. The method for detecting a sulfide corrosion site according to claim 1, If the fluorescence emitted from the attachment includes a second peak wavelength in a wavelength band of 600 nm or more and 700 nm or less, it is determined that sulfide corrosion has occurred or is occurring in the coated area of ​​the member covered by the luminescent portion of the attachment. A method for detecting a sulfide corrosion site, comprising:

3. an ultraviolet light source that irradiates ultraviolet light onto deposits attached to the surface of a metal member; a spectroscopic measurement unit that measures the spectroscopic spectrum of the fluorescence emitted from the adhesion; a determination unit that determines that sulfide corrosion has occurred in a coated area of ​​the member that is covered by the light-emitting portion of the attachment when the spectrum includes a first peak wavelength of 500 nm or more and 550 nm or less, the member is a heat transfer tube of a boiler that burns fuel in a reducing atmosphere, The deposit is ash that has adhered to the heat transfer tube. A detection device for detecting sulfide corrosion sites.

4. The detection device for a sulfide corrosion site according to claim 3, When the spectrum further includes a second peak wavelength of 600 nm or more and 700 nm or less, the determination unit determines that sulfide corrosion has occurred in the coated area of ​​the member that is covered by the light-emitting portion of the attachment. A detection device for detecting sulfide corrosion sites.

5. A zinc compound containing Zn as a main component and at least one selected from the group consisting of Mn, Cu, Cd, and Mg, When excited by ultraviolet light, the fluorescent material emits fluorescence having a first peak wavelength in a wavelength band of 500 nm or more and 550 nm or less and a second peak wavelength in a wavelength band of 600 nm or more and 700 nm or less; formed on the surface of a metal component A fluorescent substance for detecting sulfide corrosion sites or a phosphorescent substance for detecting sulfide corrosion sites, characterized in that

Images