JP5452001B2 - Corrosion monitoring sensor - Google Patents

Description

  The present invention relates to a corrosion monitoring sensor including a metal support tube through which a refrigerant flows, a sample electrode for electrochemical measurement, a counter electrode, and a reference electrode.

  In furnaces such as garbage incinerators, soda recovery boilers, and coal boilers, metal parts such as water pipes and superheater pipes are easily corroded by high-temperature molten salt and condensed water contained in incineration ash. In order to detect the corrosion state of such metal parts, for example, a corrosion monitoring sensor 1 such as Patent Document 1 using an electrochemical measurement method is used.

  FIG. 6 is a cross-sectional view showing the corrosion monitoring sensor 1 of this prior art. In the corrosion monitoring sensor 1, an opening 2 a is formed in a tip side portion of a cylindrical probe 2, and a ceramic substrate 3 is embedded therein. A sample electrode 4, a reference electrode 5, and a counter electrode 6 are attached to the ceramic substrate 3 in order from the distal end side of the probe 2. The electrodes 4, 5, 6 are connected to an electrochemical measuring instrument (not shown) via lead wires 7a, 7b, 7c. In the electrochemical measuring instrument, the polarization resistance (impedance) at the interface of the sample electrode 4 is obtained by a known electrochemical impedance method, and the corrosion rate of the sample electrode 4 is obtained from the polarization resistance by a terminal machine such as a personal computer.

Cooling air is sent from a blower (not shown) to the cooling passage 9 in the probe 2 and the flow rate of the blower is adjusted by a flow rate regulator (not shown). The flow rate regulator is connected to the sample electrode 4 via the thermocouple 8, and adjusts the temperature of the sample electrode 4 by controlling the flow rate of the blower according to the output from the thermocouple 8. By adjusting the temperature of the sample electrode 4, the state of the sample electrode 4 is made the same as that of a metal member such as a water pipe and a superheater pipe arranged in the furnace.
JP 2005-91281 A

  In the corrosion monitoring sensor 1, the ceramic substrate 3 is used to insulate the sample electrode 4, the reference electrode 5 and the counter electrode 6 from the probe 2. The ceramic substrate 3 has not only insulation but also heat insulation. . For this reason, even if cooling air flows through the cooling passage 9, the outer surface temperature of the ceramic substrate 3 does not decrease and becomes higher than the temperature of the sample electrode 4. Therefore, the ambient temperature of the sample electrode 4 becomes high. On the other hand, since metal parts, such as a water pipe and a superheater pipe, are comprised with the metal material which has heat conductivity, the whole outer surface becomes a substantially uniform temperature.

  The higher the temperature of the member and its surroundings, the harder the high-temperature molten salt and condensed water adheres to the periphery of the sample electrode 4. Therefore, the high-temperature molten salt and condensed water that adhere and deposit around the sample electrode 4 of the corrosion monitoring sensor 1 are less than the high-temperature molten salt and condensed water that actually adhere and deposit on the metal member. That is, the corrosion state may be different between the periphery of the sample electrode 4 and the metal part. Therefore, it may not be said that the corrosion state of the metal member has been estimated by detecting the corrosion state of the sample electrode 4. In order to estimate the corrosion state of the metal member more accurately, it is necessary to suppress the ambient temperature of the sample electrode 4 so that not only the sample electrode 4 but also the surrounding portion thereof is as close as possible to the temperature of the metal member. is there.

  Therefore, an object of the present invention is to provide a corrosion monitoring sensor that can suppress an increase in the ambient temperature of a sample electrode as compared with the conventional one.

The corrosion monitoring sensor of the present invention includes a cylindrical support tube made of a metal through which a refrigerant flows, a sample electrode for electrochemical measurement, a reference electrode, and a counter electrode, and the sample electrode, the reference electrode, and the counter electrode are the support tube. And the sample electrode, the reference electrode, and the counter electrode are respectively attached and embedded in the support tube, and the sample electrode, the reference electrode, and the counter electrode, Three insulating structures are provided to insulate the support pipe, and the three insulating structures are spaced apart from each other in the axial direction of the support pipe, and the support pipe is more thermally conductive than the insulating structure. it is what you are.

According to the present invention, even if the sample electrode, the reference electrode, and the counter electrode are covered with the deposit deposited on the support tube, the heat in the deposit around the sample electrode passes between the insulating structures adjacent to each other, and the refrigerant in the support tube Can escape. Thus, it is possible to lower the temperature of the deposits increases the ambient temperature of the sample electrodes, temperature rise around the sample electrodes than the conventional can be suppressed.

  In the above invention, each of the insulating structures is preferably an insulating sleeve.

  According to the above configuration, since the exposed area to the outside of the insulating structure can be reduced, the heat of the deposit deposited on the support tube can be further released to the refrigerant in the support tube, and the temperature of the deposit can be further increased. Can be lowered. This further suppresses an increase in the ambient temperature around the sample electrode.

  In the above invention, the insulating sleeve is preferably configured to be embedded by being screwed to the support tube.

  According to the above configuration, the sample electrode can be easily attached to the support tube, and damage to the sample electrode at the time of attachment can be suppressed as compared with the case of press-fitting or the like. As a result, when the corrosion state is detected and the sample electrode itself is taken out and its height and weight are measured, errors due to the damage of the sample electrode can be prevented, and the corrosion state of the sample electrode can be detected more accurately. It becomes possible.

  In the above invention, the support tube preferably has one or more fins on the inner wall thereof.

  If the said structure is followed, the cooling performance of a support pipe | tube can be improved with a refrigerant | coolant. As a result, the cooling performance of the deposit is also improved, and the temperature rise around the sample electrode can be suppressed.

In the above invention, each of the fins, the provided only on the inner wall of the distal portion of the axial support tube, the three insulating sleeves, that are disposed et the distal end side portion of the support pipe preferable.

  If the said structure is followed, the flow-path resistance in a support pipe | tube can be made small, and the heat absorption amount of the refrigerant | coolant in areas other than the front end side area | region of a support pipe | tube can be decreased. As a result, the refrigerant can sufficiently absorb heat in the tip end region of the support tube without reducing the flow velocity. Therefore, the cooling performance of the deposit is improved, and further, the increase in the ambient temperature of the sample electrode can be suppressed.

  The monitoring apparatus of the present invention is connected to the corrosion monitoring sensor according to any one of the foregoing, a blower that sends a refrigerant into the support pipe, a sample electrode and a thermocouple, and the sample electrode is a predetermined target. A flow rate regulator that adjusts the flow rate of the blower according to the output from the thermocouple so as to reach a temperature, and the sample electrode, the reference electrode, and the counter electrode are electrically connected, and the sample is obtained by an electrochemical impedance method. A corrosion state detector for detecting the corrosion state of the electrode is provided.

  According to the present invention, for example, by setting the target temperature of the sample electrode to the same temperature as that of the target member whose corrosion state is to be detected, the sample electrode can be brought into substantially the same state as the target member. Thereby, the corrosion state of the target member can be estimated more accurately by the electrochemical measuring instrument.

  According to the present invention, an increase in the ambient temperature of the sample electrode can be suppressed as compared with the conventional one.

  Below, the case where the corrosion monitoring apparatus 30 of embodiment of this invention is used for the refuse incinerator which is an example of the plant to which a metal component is exposed to high temperature molten salt is demonstrated.

  FIG. 1 is a schematic diagram showing an outline of the configuration of the waste incinerator 10. The waste incinerator 10 is a so-called stoker-type waste incinerator, and includes a generator 11 that generates power using waste heat of the incinerator. The garbage incinerator 10 includes a hopper 12 for charging garbage. The hopper 12 is connected to the main combustion chamber 14 via the chute 13, and the waste introduced from the hopper 12 is sent to the main combustion chamber 14 through the chute 13. The main combustion chamber 14 is provided with a dry stoker 15, a combustion stoker 16, and a post-combustion stoker 17. Primary air is sent from below the stokers 15, 16, and 17, and secondary air is sent from the ceiling 14 a of the main combustion chamber 14.

  Garbage in the main combustion chamber 14 is first sent to the drying stoker 15 and dried and ignited by the primary air and the radiant heat of the main combustion chamber 14. The ignited garbage is sent to the combustion stoker 16. In addition, combustible gas is generated from the ignited garbage by pyrolysis. This combustible gas is sent to the gas layer above the main combustion chamber 14 by the primary air, and flame burns with the secondary air in this gas layer. The temperature of the dust is further increased by the heat radiation accompanying the flame combustion. A part of the ignited garbage is combusted by the combustion stoker 16, and the remaining unburned portion is sent to the post-combustion stoker 17. Unburned waste is burned by the post-combustion stoker 17, and the incineration ash remaining after the combustion is discharged from the chute 18 to the outside.

  The main combustion chamber 14 is connected to a first radiation chamber 20 of a waste heat boiler 19 provided in the waste incinerator 10, and combustion exhaust gas generated by the combustion of garbage is transferred from the main combustion chamber 14 to the first radiation chamber 20. Will be sent. This combustion exhaust gas is burned again in the first radiation chamber 20, and then led to the cooling chamber 22 through the second radiation chamber 21 of the waste heat boiler 19, and then made harmless by an exhaust gas treatment facility (not shown). It is released into the atmosphere after processing.

  In the waste heat boiler 19, a plurality of water pipes 23 connected to the boiler drum 24 are provided on each of the walls that define the first radiation chamber 20 and the second radiation chamber 21. The water pipe 23 is made of carbon steel (for example, STB340), in which water sent from the boiler drum 24 flows. The water in the water pipe 23 recovers the waste heat of the first or second radiation chamber 20, 21, a part of which evaporates and becomes brackish water and is returned to the boiler drum 24. A part of the brackish water returning to the boiler drum 24 is vaporized to become steam. The steam is sent from the boiler drum 24 to a superheater 25 provided in the cooling chamber 22 to be overheated. The steam heated to high temperature and pressure in this way is sent to the turbine 26 to drive the generator.

  In the waste incinerator 10 configured as described above, a part of the incineration ash is soared by the combustion exhaust gas and is carried to the first and second radiation chambers 20 and 21 and the cooling chamber 22, and the water pipe 23 and the superheater 25 are It adheres to and deposits on the superheater tube 27. Incineration ash has high corrosivity because it contains high-temperature molten salt, and corrodes the water tube 23 and the superheater tube 27 of the superheater 25. In order to detect the corrosion state of the water pipe 23 and the superheater pipe 27, the garbage incinerator 10 is provided with a corrosion monitoring device 30. Below, the structure of the corrosion monitoring apparatus 30 is demonstrated.

  FIG. 2 is a schematic configuration diagram schematically showing the configuration of the corrosion monitoring device 30. The corrosion monitoring device 30 includes a corrosion monitoring sensor 31, an electrochemical measuring instrument 32, a terminal device 33, a blower 34, a flow rate regulator 35, and a valve 36. The corrosion monitoring sensor 31 is inserted from an opening 19 b formed in the wall 19 a of the waste heat boiler 19 and fixed to the wall 19 a of the waste heat boiler 19. In the present embodiment, the front end side of the corrosion monitoring sensor 31 is inserted so as to be disposed in the first radiation chamber 20 of the waste heat boiler 19.

  FIG. 3 is a right side view of the front end of the corrosion monitoring sensor 31 shown in FIG. In FIG. 3, a flange 60 described later is omitted. Below, it demonstrates, also referring FIG. The corrosion monitoring sensor 31 includes a long cylindrical support tube 40 made of stainless steel (SUS310J1). The support pipe 40 has a cooling passage 40a for flowing cooling air through its inner wall. In addition, a plurality of fins 41 protruding inward in the radial direction are provided on the inner wall at the tip side of the support tube 40. In the present embodiment, eight fins 41 are formed from the tip of the support tube 40 to a portion near the tip of the intermediate portion in the axial direction. The eight fins 41 are arranged on the inner wall of the support tube 40 at equal intervals in the circumferential direction and extend parallel to the axis L1 of the support tube 40.

  4 is an enlarged cross-sectional view of the tip end region X of the corrosion monitoring sensor 31 shown in FIG. FIGS. 5A to 5C are cross-sectional views of the corrosion monitoring sensor 31 taken along the cutting lines AA, BB and CC in FIG. 5A to 5C, a flange 60 described later is omitted. An opening 40b is formed at the distal end portion of the outer peripheral portion of the support tube 40, and the first to third sleeves 42, 43, and 44 having substantially cylindrical shapes are provided on the opposite side in the circumferential direction. It is embedded so as to penetrate through 40 inward and outward.

  The sleeves 42, 43, 44 are arranged in parallel to the axis L 1 of the support tube 40 at a predetermined interval in plan view, and the axis of each sleeve 42, 43, 44 is the axis L 1 of the support tube 40. Is orthogonal. The sleeves 42, 43, 44 are arranged in the first, second, and third order from the distal end side of the support tube 40. Each sleeve 42, 43, 44 has a male screw threaded on the outer peripheral portion thereof except for one end where the flange portions 42 a, 43 a, 44 a are formed, and is screwed to the support tube 40. The sleeves 42, 43, 44 embedded by screwing are fixed to the support tube 40 with an adhesive or the like.

  Furthermore, a sample electrode 45, a reference electrode 46, and a counter electrode 47 are inserted into the first to third sleeves 42, 43, 44, respectively, and the sample electrode 45 and the reference electrode 46 are fixed by welding sputtering, and the counter electrode 47. Is fixed with an adhesive. The first to third sleeves 42, 43, 44 are made of an insulating ceramic material, and insulate the sample electrode 45, the reference electrode 46, the counter electrode 47, and the support tube 40, respectively.

  The sample electrode 45 is made of the same material as the target member whose corrosion state is to be detected, in this embodiment, made of the same carbon steel (STB340) as the water tube 23, and has a cylindrical shape having a flange 45a at one end. One end of the sample electrode 45 is flush with one end of the first sleeve 42, and the other end protrudes from the first sleeve 42. The sample electrode 45 is mounted by inserting an attachment member 52 having a sample electrode lead wire 51 made of platinum connected to the other end thereof, and is electrically connected to the sample electrode lead wire 51. Further, a sample electrode thermocouple 53 is also attached to the other end of the sample electrode 45. In addition to the sample electrode thermocouple 53, a support tube thermocouple 56 for detecting the temperature of the support tube 40 is provided at the tip of the support tube 40. Although not shown, the corrosion monitoring sensor 31 is A gas temperature thermocouple for detecting the temperature of the surrounding gas is also provided.

  The reference electrode 46 includes a mullite-made Tamman tube 46a having one end formed in a dome shape. The tube 46 a is configured such that one end side thereof protrudes outward from the second sleeve 43 when inserted into the second sleeve. Further, the tube 46a is filled with an electrolyte (NaCl, KCl, etc. mixed with 1/10 molar ratio of AgCl), and the other end of the tube 46a is closed by a lid 46b. Further, a spiral silver wire 46c is enclosed in the tube 46a, and the silver wire 46c is electrically connected to a reference electrode lead wire 54 made of platinum through a through hole formed in the lid body 46b. ing.

  The counter electrode 47 is made of platinum and has a cylindrical shape having a flange 47a at one end. One end of the counter electrode 47 is flush with one end of the third sleeve 44, and the other end projects from the third sleeve 44. The counter electrode 47 is electrically connected to a counter electrode lead wire 55 made of platinum at the other end.

  For attaching the sleeves 42, 43, 44, first, the electrodes 45, 46, 47 are respectively attached to the sleeves 42, 43, 44, and they are screwed from the outside of the support tube 40, so that each of the sleeves 42, 43, 44 is attached. Continue rotating until the other end comes out into the support tube 40. When the other end portions of the sleeves 42, 43, 44 come out, a jig or hand (not shown) is inserted from the opening 40 b of the support tube 40, and one end of each sleeve 42, 43, 44 faces the outer peripheral portion of the support tube 40. The other ends of the three sleeves 42, 43, and 44 are turned with a jig or hand until they become one. When the ends of all the sleeves 42, 43, 44 are flush with each other, the opening 40b is closed with the lid 40c, and the lid 40c is welded to the support pipe body 40d.

  With such a method, the electrodes 45, 46, and 47 can be easily attached to the support tube 40, and damage to the sample electrode 45 at the time of attachment can be suppressed as compared with the case of press-fitting or the like. Thereby, after the corrosion state is detected, when the sample electrode itself is taken out and the height and weight thereof are measured, errors due to the damage of the sample electrode 45 can be prevented, and the more accurate corrosion state of the sample electrode 45 can be prevented. Can be detected.

  The sample electrode 45, the reference electrode 46, and the counter electrode 47 attached in this way are arranged along the longitudinal direction of the support tube 40, and the sample electrode 45, the reference electrode 46, and the counter electrode 47 are attached at the same angular position in the circumferential direction. Will be. For this reason, the incineration ash adhering to the sample electrode 45, the reference electrode 46, and the counter electrode 47 coincides even though the incineration ash adhering to the outer peripheral surface of the support tube 40 differs in the circumferential position. It becomes possible to detect the corrosion state of the electrode 45 satisfactorily.

  Returning to FIG. 2 again, the configuration of the base end side of the support tube 40 will be described. A disc-shaped flange 60 is formed on the base end portion of the outer peripheral portion of the support tube 40 so as to protrude outward in the radial direction of the support tube 40. Further, the base end portion of the support tube 40 is screwed into the first opening 61 a of the T-shaped tube 61. The T-shaped tube 61 is sealed by a sealing plug 62 screwed into a second opening 61b on the opposite side of the first opening 61a, and a third opening 61c, which is another opening. Is connected to the blower 34 via the pipe joint 63.

  The sealing plug 62 includes a cylindrical screwing member 62a and a sealing plate 62b. The distal end of the screwing member 62a is screwed into the second opening 61b, and the other end of the screwing member 62a is provided with a sealing plate 62b so as to close the opening on the base end side of the screwing member 62a. It is fixed. Each lead wire 51, 54, 55 and each thermocouple 53, 56 are drawn to the sealing plate 62b through the support tube 40, and are further taken out through a through hole formed in the sealing plate 62b. It is. The lead wires 51, 54, and 55 are electrically connected to the electrochemical measuring instrument 32, and the thermocouples 53 and 56 are electrically connected to the flow rate regulator 35. The lead wires 51, 54, and 55 are inserted into a sleeve tube 57 made of insulator and passed through the support tube 40 so as not to short-circuit each other.

  The electrochemical measuring instrument 32 is a device that measures the corrosion rate of the sample electrode 45 by a known electrochemical impedance method. Specifically, the electrochemical measuring instrument 32 detects a current flowing through the reference electrode for each frequency by causing a weak AC signal of various frequencies to flow through the sample electrode 45 and the counter electrode 47 using a frequency response analyzer. The frequency response characteristic of the impedance with the reference electrode 46 is obtained. The frequency response characteristics of this impedance converge on the low frequency side (f-0) and the high frequency side (f + ∞), and the difference between these convergence values corresponds to the polarization resistance (impedance) at the interface of the sample electrode 45. The electrochemical measuring instrument 32 obtains the polarization resistance (impedance) at the interface of the sample electrode 45 from the frequency response characteristic of the impedance described above based on the relationship as described above.

  Further, the corrosion rate and the polarization resistance at the interface of the sample electrode 45 have a correlation that the corrosion rate decreases depending on the reciprocal of the polarization resistance. In the terminal device 33, the correlation between the polarization resistance of the member made of the same material as the sample electrode 45 and the corrosion rate obtained in advance is stored in advance, and this correlation and the polarization resistance obtained by the electrochemical measuring device 32 are stored. Based on the above, the corrosion rate of the sample electrode 45 is calculated. The corrosion rate is calculated by the terminal 33 every predetermined time. The terminal device 33 accumulates the calculated corrosion rates and integrates the accumulated corrosion rates to detect the amount of corrosion of the sample electrode 45. Thus, by detecting the corrosion rate and corrosion amount of the sample electrode 45, the corrosion rate and corrosion amount of the water pipe 23 or the superheater pipe 27 can be estimated.

  The blower 34 is for sending cooling air to the cooling passage 40 a of the support pipe 40, and the blower 34 is provided with a flow rate regulator 35 for controlling the flow rate from the blower 34. As described above, the flow rate regulator 35 is connected to the thermocouples 53 and 56, and the temperature of the sample electrode 45 is determined in advance according to the output from the thermocouple 53, in this embodiment, the water pipe 23. The flow rate of the cooling air from the blower 34 is controlled so that the temperature is 300 ° C. Thereby, the sample electrode 45 can be made into the substantially the same state as the said water pipe 23, and the more accurate corrosion state of the water pipe 23 can be estimated. A valve 36 for adjusting the amount of air is provided between the blower 34 and the pipe joint 63.

  In the corrosion monitoring device 30, the flow rate adjuster 35 adjusts the flow rate of the blower 34 according to the output from the thermocouple 53 to adjust the temperature of the sample electrode 45 to 300 ° C., while the electrochemical measuring device 32 and the terminal device 33. Thus, the corrosion rate of the sample electrode 45 is detected every predetermined time. The detected corrosion rate is accumulated in the terminal device 33, and the amount of corrosion of the sample electrode 45 is calculated based on the accumulated corrosion rate. Based on the detected corrosion rate and corrosion amount of the sample electrode 45, the corrosion rate and corrosion amount of the water tube 23 can be estimated.

  During the measurement, incineration ash flying in the first radiation chamber 20 accumulates and accumulates on the corrosion monitoring sensor 31 on the outer peripheral surface of the support pipe 40. Thereby, the sample electrode 45, the reference electrode 46, and the counter electrode 47 are covered with incineration ash. The incinerated ash covering the sample electrode 45, the reference electrode 46, and the counter electrode 47 is not cooled sufficiently because the position where the corrosion monitoring sensor 31 is disposed is close to the first radiation chamber 20 and the main combustion chamber 14, and the temperature does not drop sufficiently. . In addition, in the incineration ash deposited on the support tube 40, particularly in the portion facing the sample electrode 45, the reference electrode 46 and the counter electrode 47, the incineration ash is deposited so as to cover it, so that heat is difficult to escape, Especially the temperature does not drop. Therefore, the sample electrode 45, the reference electrode 46, and the counter electrode 47 are likely to become high temperature.

  In the conventional corrosion monitoring sensor 1, the ceramic substrate 3 having a considerably higher heat insulating property than the metal parts such as the support tube 40 is provided in the portion where the incineration ash is deposited, and the heat is more difficult to escape. Therefore, when the corrosion monitoring sensor 1 is provided in the first radiation chamber 20, the sample electrode 4, the reference electrode 5, and the counter electrode 6 become high temperature, and it is difficult to set the temperature to 700 ° C. or lower.

  In contrast, in the corrosion monitoring sensor 31 of the present embodiment, the sleeves 42, 43, and 44 are made of ceramic and have heat insulation properties. However, a metal material of the support tube 40 having thermal conductivity is interposed therebetween. ing. Therefore, the heat of the incineration ash can escape to the cooling air in the cooling passage 40a through them, and the incineration ash on the support pipe 40 can be cooled. By cooling the incinerated ash, it is possible to suppress an increase in the ambient temperature of the sample electrode 45, the reference electrode 46, and the counter electrode 47, specifically, an increase in the temperature of the sleeves 42, 43, and 44. In this way, by suppressing the temperature rise of the sleeves 42, 43, 44, the water pipe 23 disposed in the place where the sample electrode 45 and its peripheral state are close to the main combustion chamber 14 and at a high room temperature like the first radiation chamber 20. The corrosion state of the water pipe 23 can be estimated more accurately.

  The distance between the axes of the sleeves 42, 43, and 44 adjacent to each other is such that the polarization resistance obtained by the electrochemical impedance method exhibits a good value and also performs the cooling function of the incineration ash, for example, 20 mm. ~ 30 mm. The sleeves 42, 43, 44 have a thickness of 2 mm to 3 mm, for example. However, these intervals and thickness only show a preferable example, and are not limited to this range.

  Further, by providing the fin 41 on the inner wall of the support tube 40, the cooling function of the support tube 40 is improved. Thereby, the heat of the incineration ash can be further released to the cooling air, and the cooling function of the incineration ash is further improved. Since the temperature of the sample electrode 45 can be adjusted by adjusting the flow rate of the blower, the range in which the temperature of the sample electrode 45 can be adjusted is widened by improving the cooling function of the incineration ash, and can be used in various environments. .

  In addition, the corrosion monitoring sensor 31 has the flow resistance of the cooling passage 40a by forming the fin 41 only in the tip side portion of the support tube 40, specifically, in the portion where the sleeves 42, 43, 44 are provided. In addition, the cooling air is prevented from absorbing heat as much as possible from the tip of the support tube 40 to portions other than the intermediate portion. As a result, the flow rate of the cooling air is not reduced, and sufficient heat absorption is possible on the tip side of the support tube 40, and the cooling function of the incinerated ash is further improved. Thereby, the adjustable range of the temperature of the sample electrode 45 is expanded.

  In this embodiment, the sleeves 42, 43, 44 are provided for each of the electrodes 45, 46, 47. However, the reference electrode 46 and the counter electrode 47 are provided on an insulating ceramic substrate, and this ceramic substrate is used as the first sleeve. 42 may be embedded in the outer peripheral portion of the support tube 40 with a gap. With such a configuration, the heat of the incinerated ash deposited from between the first sleeve 42 and the ceramic substrate can be released, the temperature of the incinerated ash in the vicinity of the sample electrode 45 can be lowered, and the sample electrode Temperature rise can be suppressed.

  In the present embodiment, the number of fins 41 provided is eight, but eight is the most preferable number, and the cooling function of the support tube 40 can be improved even when the number is seven or less and nine or more. . Therefore, the number of fins 41 is not limited to eight. In the present embodiment, the number of cooling passages 40a formed in the support pipe 40 is one. However, two or more cooling passages 40a may be used, and the flow through the cooling passage 40a is not limited to cooling air, and cooling is performed. Gas and coolant may be used. In the case of the cooling liquid, it is preferable that the cooling liquid is circulated instead of being discharged into the first radiation chamber 20 like the cooling air of the present embodiment.

  In the present embodiment, the corrosion monitoring sensor 31 is disposed in the first radiation chamber 20 to detect the corrosion state of the water pipe 23, but in order to detect the corrosion state of the superheater pipe 27 of the superheater 25, It may be arranged in the two radiation chambers 21 or the cooling chamber 22 and has the same effect.

  In the present embodiment, the case where the corrosion monitoring device 30 is used in the waste incinerator 10 has been described. However, the use location is not limited to the waste incinerator 10. For example, if the plant has an environment in which deposits containing high-temperature molten salt accumulate on metal parts and corrode metal parts, such as a soda recovery boiler and coal fired boiler, the corrosion monitoring device 30 can be used and applied. Can do. The configuration of the waste incinerator 10 is merely an example, and can be applied even if the configuration is different from the above configuration. Furthermore, the present invention is not limited to the embodiments described above, and the configuration can be changed, added, or deleted without departing from the spirit of the present invention.

It is the schematic which shows the outline of a structure of a refuse incinerator. It is a schematic block diagram which shows the structure of a corrosion monitoring apparatus roughly. It is the right view which looked at the front-end | tip of the corrosion monitoring sensor of FIG. 2 toward the paper surface from the right side. It is sectional drawing to which the front end side area | region X of the corrosion monitoring sensor shown in FIG. 2 was expanded. (A)-(c) is sectional drawing when a corrosion monitoring sensor is each cut | disconnected by cutting lines AA, BB, and CC of FIG. It is sectional drawing which shows the corrosion monitoring apparatus of the prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 30 Monitoring apparatus 31 Corrosion monitoring sensor 32 Electrochemical measuring device 33 Terminal device 34 Blower 35 Flow controller 40 Support pipe 40a Cooling passage 41 Fin 42 1st sleeve 43 2nd sleeve 44 3rd sleeve 45 Sample electrode 46 Reference electrode 47 Counter electrode

Claims (6)

A cylindrical support tube made of a metal through which a refrigerant flows, a sample electrode for electrochemical measurement, a reference electrode, and a counter electrode are provided, and the sample electrode, the reference electrode, and the counter electrode are arranged side by side in the axial direction of the support tube. A corrosion monitoring sensor,
The sample electrode, the reference electrode, and the counter electrode are respectively attached and embedded in the support tube, and includes three insulating structures that insulate the sample electrode, the reference electrode, the counter electrode, and the support tube,
The three insulating structures are arranged spaced apart from each other in the axial direction of the support pipe ,
The corrosion monitoring sensor according to claim 1, wherein the support pipe is more thermally conductive than the insulating structure .   The corrosion monitoring sensor according to claim 1, wherein each of the insulating structures is an insulating sleeve.   The corrosion monitoring sensor according to claim 2, wherein the insulating sleeve is configured to be embedded by being screwed to the support pipe.   The corrosion monitoring sensor according to any one of claims 1 to 3, wherein the support pipe has one or a plurality of fins on an inner wall thereof. Each of the fins is provided only on the inner wall of the tip end portion in the axial direction of the support pipe,
It said three insulating sleeves, corrosion Morita training sensor according to claim 4, characterized in that is provided et the portion of the distal end side. The corrosion monitoring sensor according to any one of claims 1 to 5,
A blower for sending a refrigerant into the support pipe;
A flow rate regulator that is connected to the sample electrode by a thermocouple and adjusts the flow rate of the blower according to the output from the thermocouple so that the sample electrode has a predetermined target temperature;
A corrosion monitoring apparatus comprising: a corrosion state detector electrically connected to the sample electrode, the reference electrode, and the counter electrode and detecting a corrosion state of the sample electrode by an electrochemical impedance method.

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