JP6424534B2 - boiler - Google Patents

Description

  The present invention relates to a boiler constituting a boiler group consisting of a plurality of boilers.

  Conventionally, a boiler body to which boiler feed water is internally supplied, a burner for heating the inside of the boiler body, a drainage portion for discharging the boiler water stored inside the boiler body to the outside, and drainage of concentrated boiler water There is known a boiler provided with a discharge control unit which controls to discharge from the unit. In such a boiler, boiler water in a boiler body is heated by a burner to generate steam. In this state, if the boiler is continuously operated, boiler water may be excessively concentrated. And a boiler has a possibility of causing the phenomenon called what is called a "carry over" by which the dissolved substance contained in boiler water mixes in steam, and is carried out to the exterior of a boiler.

  As described above, when the concentration of boiler water is increased in the boiler, carry-over is caused, resulting in deterioration of the dryness of the steam and damage to related devices such as valves. Therefore, in order to prevent the concentration degree from becoming too high and to improve the water quality of the boiler water, a blow-down process is performed to discharge the concentrated boiler water from the drainage portion. The blow-down process is a process of supplying fresh makeup water periodically from the outside and discharging a part of the highly concentrated boiler water to the outside to dilute the boiler water. In addition, when the boiler water is diluted and the pH value or chemical concentration decreases, the boiler main body is corroded, so when the blow-down process is performed, the chemical such as an anticorrosive agent (corrosion inhibitor) is added to the boiler water A process of supplying (hereinafter, also referred to as "drug treatment") is also performed (see, for example, Patent Document 1). In the boiler described in Patent Document 1, it is carried out in the chemical injection process to supply the medicine in an amount corresponding to the amount of makeup water to the boiler.

  By the way, in recent years, in a boiler group consisting of a plurality of boilers (for example, multi-can installation system of a small once-through boiler), it is confirmed that the backflow phenomenon that steam generated from the burning boiler flows into the standby boiler (See, for example, Patent Documents 2 and 3). Usually, a steam delivery line of a boiler is provided with a steam check valve that prevents the backflow of steam to the boiler. However, if the seal of the valve body and the valve seat becomes incomplete due to the deterioration of the steam check valve, etc., the above-described backflow phenomenon of steam will occur. And the high temperature steam which flowed back is changed into condensed water by being absorbed by low temperature parts (for example, metallic materials and boiler water), such as a boiler main part and a steam separator.

Japanese Patent Application Laid-Open No. 5-18507 JP, 2013-195021, A JP, 2013-204921, A

  When the backflowed steam is changed to condensed water, the boiler water is diluted with the condensed water. As a result, the pH value and the silica concentration of the boiler water become lower than the predetermined range, and there is a problem that the boiler main body is easily corroded.

  An object of this invention is to provide the boiler which can detect easily that backflow of the steam in the boiler main body.

The present invention is a boiler that constitutes a boiler group consisting of a plurality of boilers, comprising: an upper header, a lower header, and a plurality of water tubes connected to the upper header and the lower header; A steam reverse provided in a burner for heating the inside of the boiler body by burning, a steam / water separator communicated with the upper header and the lower header, and a steam delivery line connected to the steam / water separator A check valve, a condensed water electric conductivity sensor for detecting the electric conductivity of condensed water generated in the area between the plurality of water pipes and the steam check valve, and a detected value of the condensed water electric conductivity sensor And a determining unit that determines the presence or absence of the backflow of steam to the boiler when the boiler is stopped .

  Further, the condensed water electric conductivity sensor detects the electric conductivity of the condensed water staying in the upper header, or the electric conductivity of the condensed water staying in the air-water separator, and the determination It is preferable that, when the detection value of the condensed water electrical conductivity sensor exceeds a first predetermined value, the unit determine that the backflow of steam to the stopped boiler has occurred.

  Furthermore, a boiler water conductivity sensor for detecting the conductivity of the boiler water is further provided, wherein the condensed water conductivity sensor detects the conductivity of the condensed water staying in the upper header, The determination unit is configured to determine the backflow of steam to the stopped boiler when the difference between the detected value of the boiler water electrical conductivity sensor and the detected value of the condensed water electrical conductivity sensor falls below a second predetermined value. Is preferably determined.

  According to the present invention, it is possible to provide a boiler capable of easily detecting the backflow of steam in the boiler body.

It is a figure showing an outline of boiler system 1 containing a plurality of boilers 20 concerning a 1st embodiment of the present invention. It is a figure which shows the relationship between the combustion pattern and priority of each boiler, and the steam pressure zone of the steam pressure control range. It is a figure showing an outline of boiler system 1 concerning a 1st embodiment of the present invention. It is a functional block diagram concerning control of boiler system 1 concerning a 1st embodiment of the present invention. It is a schematic sectional drawing which shows the electrode part 430 of the condensed water electrical conductivity sensor 422 of the boiler system 1 which concerns on 1st Embodiment of this invention. It is a schematic plan view which shows the electrode part 430 of the condensed water electrical conductivity sensor 422 of the boiler system 1 which concerns on 1st Embodiment of this invention. It is a flow chart which shows a processing procedure of backflow detection in boiler 2 concerning a 1st embodiment of the present invention. It is a flowchart which shows the process procedure of the back flow detection in the boiler 2 which concerns on 2nd Embodiment of this invention.

  Hereinafter, a boiler system 1 according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a boiler system 1 including a plurality of boilers 20 according to a first embodiment of the present invention. FIG. 2 is a view showing the relationship between the combustion pattern and priority of each boiler and the steam pressure zone of the steam pressure control range.

  As shown in FIG. 1, a boiler system 1 according to the present embodiment includes a boiler group 2 including a plurality of (three) boilers 20 and a steam header 50 as a steam collecting unit for collecting steam generated in the boiler 20. And a steam pressure sensor 51 as a steam pressure measuring means, and a number control device 53 as a number control means. The boilers 20 constitute a boiler group 2 composed of a plurality of (three) boilers 20.

  The upstream side of the steam header 50 is connected to the boiler group 2 (each boiler 20) via a steam pipe 61. The downstream side of the steam header 50 is connected to a steam using facility 58 (loading device) via a steam pipe 62. The steam header 50 regulates the mutual pressure difference and pressure fluctuation of the respective boilers 20 by collecting and storing the steam generated in the boiler group 2 and supplies the pressure-controlled steam to the steam using facility 58 It is supposed to be.

  The vapor pressure sensor 51 is electrically connected to the number control device 53 via a signal line 71. The vapor pressure sensor 51 measures the vapor pressure inside the vapor header 50 (the pressure of the vapor generated by the boiler group 2), and the number of signals (vapor pressure signal) related to the measured vapor pressure via the signal line 71 It transmits to the control device 53.

  The boiler system 1 of the present embodiment can supply the steam generated by the boiler group 2 to the steam using facility 58 via the steam header 50. The load (required load) required in the boiler system 1 is substituted by the steam pressure (physical quantity) inside the steam header 50 measured by the steam pressure sensor 51 at the time of number control.

  The increased demand due to the increased demand for the steam using facility 58 causes the steam pressure inside the steam header 50 to decrease if the amount of steam supplied is insufficient. On the other hand, when the demand for the steam using facility 58 decreases, the load decreases, and if the amount of supplied steam becomes excessive, the steam pressure inside the steam header 50 will increase. For this reason, the fluctuation of the load can be monitored by the vapor pressure signal from the vapor pressure sensor 51. The boiler system 1 is configured to calculate an evaporation amount corresponding to the consumed steam amount of the steam using facility 58 based on the steam pressure.

  The boiler 20 is composed of a step value control boiler having a plurality of step combustion positions. In the step value control boiler, the amount of combustion is controlled by selectively turning on / off the combustion, adjusting the size of the flame, etc., and the amount of combustion can be made stepwise according to the selected combustion position. It is a boiler that can be increased or decreased.

  The amount of combustion at each combustion position is set so as to generate an amount of steam corresponding to the pressure difference of the steam pressure (control target) in the steam header 50 to be controlled. The amount of combustion and the combustion capacity (the amount of combustion in a high combustion state) at each combustion position are set equal to each other in the three boilers 20 each including a step value control boiler.

The boiler 20 in the present embodiment is
1) Combustion stop state (burn stop position: 0%)
2) Low combustion state (low combustion position: 50%)
3) High combustion state (high combustion position: 100%)
A so-called three-position control that can be controlled to three stages of combustion states (combustion position, load factor) is performed. In this case, if the combustion amount in the high combustion state is regarded as 1.0, the combustion amount of each boiler 20 can be changed in 0.5 increments.

  The N position control means that the combustion amount of the step value control boiler can be controlled stepwise to the N position including the combustion stop state. The number of combustion positions may be 2 positions (that is, only on / off), 4 positions (a combustion stop position, a low combustion position, a middle combustion position and a high combustion position), or 5 positions or more.

  In the boiler group 2, a combustion pattern is set which is a combination of each boiler 20 and each combustion position thereof. In the present embodiment, as shown in FIG. 2, the combustion pattern is “H” when the boiler is in the high combustion state, “L” when the boiler is in the low combustion state, and “L” when the combustion is stopped. As "." As the combustion pattern, a pattern in which the amount of combustion is smaller is selected as the vapor pressure detected by the vapor pressure sensor 51 becomes higher, and a pattern in which the amount of combustion is larger as the vapor pressure is reduced is selected. As shown in FIG. 2, the vapor pressure control range is divided into seven vapor pressure zones, and the corresponding combustion pattern, in other words, the combustion state (combustion position) is set for each vapor pressure zone, and the vapor pressure is The amount of combustion is determined depending on which pressure zone it corresponds to. Seven combustion patterns are set corresponding to seven vapor pressure zones.

  Priorities are set to the plurality of boilers 20, respectively. In the present embodiment, as shown in FIG. 2, among the three boilers 20, the priority of the first unit is first, the priority of the second unit is second, and the priority of the third unit is third It is set to. In the seven vapor pressure zones, in the uppermost vapor pressure zone, all the boilers 20 are in the combustion stop state "-", and in the lowest vapor pressure zone, all the boilers 20 are in the high combustion state "H" It is. The combustion state is changed from "-" to "L" to "H" in the order from the first unit to the third unit from the uppermost vapor pressure zone to the lowermost vapor pressure zone.

  In the present embodiment, after the high priority boiler is changed from the low combustion state “L” to the high combustion state “H”, the boiler with the next highest rank is the combustion stop state “−” to the low combustion state “L”. Will be changed to It should be noted that after the boiler with the higher priority is changed from the combustion stop state "-" to the low combustion state "L" and before the state is changed to the high combustion state "H", the boiler with the next higher rank is stopped The state “−” may be changed to the low combustion state “L”.

  As shown in FIG. 1, the boiler 20 measures the steam pressure inside the boiler main body 21 where combustion is performed, the local control device 25 that controls the combustion position (combustion state) of each boiler 20, and each boiler 20 And a local vapor pressure measuring unit 29 as vapor pressure measuring means.

  The local control device 25 can control the boilers 20 to change the combustion position (combustion state) according to the required load. The local control device 25 controls each boiler 20 based on the number control signal by the number control device 53 at the time of number control, and directly controls the boiler 20 at the time of local control.

  The local vapor pressure measurement unit 29 is constituted of, for example, a vapor pressure sensor and a vapor pressure switch, or only of the vapor pressure switch, and measures the vapor pressure inside the upper header 23 (described later) of each boiler 20. The local vapor pressure measurement unit 29 measures the vapor pressure used when performing local control of each boiler 20.

  Each boiler 20 is electrically connected to a number control device 53 via a signal line 72. The makeup water W1 and the fuel F are supplied to each boiler 20. Dry steam SM2 is delivered from each boiler 20 (see FIG. 3). In addition, the structure of the periphery of each boiler 20 and each boiler 20 is mentioned later.

  The local control device 25 transmits a signal used by the number control device 53 at the time of number control to the number control device 53 via the signal line 72. Examples of the signal used by the number control device 53 include a signal such as a load required for the boiler 20, an actual combustion state of the boiler 20, and other data. Further, when the boiler 20 to be controlled is operable, the local control device 25 transmits a signal (operable signal) indicating that the boiler 20 is operable to the number control device 53 via the signal line 72.

  When the number control is performed, the local control device 25 shifts the combustion position to the lower side when the vapor pressure inside the vapor header 50 measured by the vapor pressure sensor 51 becomes high (to the combustion stop position Of each boiler 20 so as to reduce the amount of evaporation, while reducing the amount of evaporation, while shifting the combustion position higher when the vapor pressure inside the vapor header 50 is lowered, to increase the amount of evaporation. Control the position.

  When local control is performed, the local control device 25 shifts the combustion position to a lower side when the vapor pressure inside the boiler 20 measured by the local vapor pressure measurement unit 29 becomes higher (combustion stop position To reduce the amount of evaporation), while shifting the combustion position to a higher side when the steam pressure inside the boiler 20 is lowered, to increase the amount of evaporation, the combustion of each boiler 20 Control the position.

  The number control device 53 is electrically connected to each boiler 20 via a signal line 72. The number control device 53 controls the number of the boilers 20 so that the boilers 20 are operated with high boiler efficiency (combustion efficiency). In addition, when local control is performed by each boiler 20, the number control by the number control device 53 is not performed.

  The number control device 53 calculates the required combustion amount of the boiler group 2 and the combustion state of each boiler 20 corresponding to the required combustion amount based on the signal such as the required load received from each boiler 20, and The number control signal is transmitted to the local control device 25. Thereby, the number control device 53 controls the amount of combustion of each boiler 20 and performs the number control of the boiler group 2.

  The number control device 53 receives the steam pressure signal from the steam pressure sensor 51 via the signal line 71. The number control device 53 sets the necessary amount of combustion corresponding to the required load based on the vapor pressure signal from the vapor pressure sensor 51, and instructs each boiler 20 to change the combustion position according to the required amount of combustion, 3 The amount of combustion of the boilers 20 of a stand is controlled.

  Specifically, based on the vapor pressure measured by the vapor pressure sensor 51, the number control device 53 selects the combustion pattern so that the vapor pressure falls within a predetermined vapor pressure control range (see FIG. 2). The number control device 53 instructs the boiler 20 to raise the combustion position from the combustion stop position to the low combustion position or from the low combustion position to the high combustion position when the combustion amount is insufficient due to the fluctuation of the required load. . If the amount of combustion is excessive due to fluctuations in required load, the boiler will be instructed to lower the combustion position from the high combustion position to the low combustion position, from the low combustion position to the combustion stop position, or from the high combustion position to the combustion stop position. Do on 20.

  In addition, combustion of the boiler 20 or its stop can also be handled by a virtual boiler unit. The virtual boiler is a boiler in which differences in the combustion position (burnup amount) in the boiler (low combustion position, middle combustion position, high combustion position, etc.) are regarded as independent boilers, and the evaporation amounts thereof are assumed in the boiler. For example, in the case of an on / off boiler (two-position boiler), there is one virtual boiler, which corresponds to the actual number of physical boilers. Further, even if there is only one physically located three-position boiler, it can be virtually counted that there are two low-fired boilers and a (high-burning amount-low-burning amount) boiler. The four-position boiler can be virtually counted as three low-burning-rate boilers, (medium-burning-low-burning) boilers, and (high-burning-middle-burning) boilers. Therefore, if the three-position boiler is in a low combustion state, if the combustion instruction is issued to the low combustion amount boiler, it can be handled for control, while the (high combustion amount-low combustion amount) boiler If a command to stop combustion is issued, control can be handled.

  The number control device 53 is connected to the local control device 25 of each boiler 20 via a signal line 72. The number control device 53 gives various instructions to the local control device 25 of each boiler 20 via the signal line 72, receives various data from the local control device 25, and the like for the three boilers 20. Control as described above. The local control device 25 of each boiler 20 controls the boiler 20 according to the instruction when it receives a signal indicating a change instruction of the combustion position from the number control device 53. If the actual amount of combustion is insufficient with respect to the required amount of combustion determined from the load amount of the boiler system provided with a plurality of boilers, the combustion instruction is issued to the boiler 20, and if the actual amount of combustion is excessive, It instructs the boiler 20 to stop combustion.

  Next, the configuration of each boiler 20 and the configuration around each boiler 20 will be described. FIG. 3 is a view schematically showing the boiler system 1 according to the first embodiment of the present invention. FIG. 4 is a functional block diagram related to control of the boiler system 1 according to the first embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing a first condensed water electrical conductivity sensor 422 of the boiler system 1 according to the first embodiment of the present invention. FIG. 6 is a schematic plan view showing the first condensed water electrical conductivity sensor 422 of the boiler system 1 according to the first embodiment of the present invention. The configurations of the boilers 20 are the same as each other, so one boiler 20 will be described.

  As shown in FIG. 3, the boiler system 1 includes a boiler 20, a water softening apparatus 3, a water supply tank 5, a corrosion inhibitor adding apparatus 81, a steam header 50, and a hardness sensor 41. In FIG. 3, the path of the electrical connection is indicated by a broken line.

  Further, the boiler system 1 includes a makeup water line L1, a fuel supply line L2, a blow line L3 as a discharge unit, a steam take-out line L4, a steam delivery line L5 as the steam pipe 61, and a precipitation line L6. And a drug addition line L7. The “line” in the present specification is a generic name of lines capable of fluid flow, such as flow paths, paths, and conduits. Further, “boiler feed water” in the present specification refers to water supplied to the boiler main body 21 (supplement water such as soft water and pure water, and in the case where there is condensed water recovery, water mixed with condensed water and makeup water) means. "Boiler water" means water stored in the boiler body (including both unconcentrated and concentrated states).

  The boiler 20 is an apparatus for generating steam to be supplied to a facility using steam (not shown). The boiler 20 includes a boiler body 21, a burner 27, a combustion chamber 26, and a water level detector 28 as water level detection means. Water supply pump 6 as boiler water supply means, air-water separator 7, control device 10 as determination unit, blow valve 93, main steam valve 94, steam check valve 95, boiler water electrical conductivity A sensor 421, and a first condensed water electrical conductivity sensor 422 and a second condensed water electrical conductivity sensor 423 as condensed water electrical conductivity sensors are provided. The boiler body 21 forms a pressure vessel composed of a plurality of water pipes 22, an upper header 23, and a lower header 24.

As described later, the boiler 20 according to the present embodiment has a structure of a multi-tube type once-through boiler. In addition, what is used at gauge pressure of 1 MPa or less and whose heat transfer area is 10 m ² or less is referred to as a small once-through boiler (The Industrial Safety and Health Law Enforcement Ordinance, Article 1, Item 4).

  The makeup water line L1 is a line for supplying makeup water (boiler feed water) W1 to the boiler body 21. The upstream end of the makeup water line L1 is connected to a supply source (not shown) of the makeup water W1. The downstream end of the makeup water line L1 is connected to the lower header 24 (described later) of the boiler body 21. Hard water softening device 3, hardness sensor 41, water supply tank 5, connection part J1, and water supply pump 6 are provided in the replenishment water line L1 from the supply source toward the boiler 20 in order.

  The water softening apparatus 3 generates soft water by replacing hardness components contained in the raw water such as tap water, ground water, industrial water, etc. with sodium ions (or potassium ions). The water softening apparatus 3 has a cation exchange resin bed 3a. The cation exchange resin bed 3 a performs a water softening treatment of the makeup water W 1 supplied to the boiler main body 21. The water softening apparatus 3 supplies treated water (soft water) obtained by softening the raw water W0 with the cation exchange resin bed 3a toward the boiler 20 as a makeup water (boiler feed water) W1.

  The hardness sensor 41 detects the hardness of the makeup water W1 softened by the water softening device 3. Information on the hardness of the makeup water W1 detected by the hardness sensor 41 is transmitted to the control device 10 as a detection signal.

  The water supply tank 5 stores the treated water softened by the hard water softening device 3 as a makeup water W1. The makeup water W 1 stored in the water supply tank 5 is supplied to the boiler body 21 by the water supply pump 6. The water supply pump 6 sucks the makeup water W1 from the water supply tank 5, and delivers the makeup water W1 flowing through the makeup water line L1 toward the boiler main body 21. The water supply pump 6 is electrically connected to the control device 10. The timing at which the feed water pump 6 sends the makeup water W1 to the boiler main body 21 is controlled by a drive signal transmitted from the control device 10.

  The downstream end of the drug addition line L7 is connected to the connection portion J1. The corrosion inhibitor addition device 81 is connected to the end on the upstream side of the drug addition line L7. The corrosion inhibitor adding device 81 is a device that adds (supplies) a corrosion inhibitor (chemical) to the makeup water W1 supplied to the boiler main body 21. The corrosion inhibitor adding apparatus 81 can execute a chemical supply process for supplying a corrosion inhibitor to the boiler water W2 stored in the boiler main body 21 so as to have a water quality that can suppress the corrosion of the boiler main body 21. . The corrosion inhibitor is a chemical which is mainly used to suppress the corrosion of the water pipe 22 and the lower header 24.

  The corrosion inhibitor addition device 81 is electrically connected to the control device 10. The timing and amount of addition of the corrosion inhibitor from the corrosion inhibitor addition device 81 to the connection portion J1 of the makeup water line L1 are controlled by the drive signal transmitted from the corrosion inhibitor addition control unit 103 (described later) of the control device 10. Be done.

  The boiler body 21 is composed of a water tube group vertically provided between the upper and lower headers, and constitutes a main part of the outer shape of the boiler 20. In the boiler main body 21, the makeup water W1 supplied by the makeup water line L1 is internally stored as the boiler water W2. The boiler water W2 includes water that is temporarily stored in the boiler body 21 as the boiler water W2 and then taken out as steam and returned to the boiler body 21. For example, the boiler water W2 also includes separated water W4 separated by the steam-water separator 7 (described later) and returned to the boiler main body 21.

  The plurality of water pipes 22 are disposed to extend in the vertical direction of the boiler body 21. The upper header 23 is disposed on the upper portion of the boiler body 21. The upper header 23 is configured by, for example, an annular container. The upper end portions of the plurality of water pipes 22 are connected to and connected to the upper header 23. The upper header 23 is connected to an end on one side of a steam takeout line L4 described later.

  A first condensed water electrical conductivity sensor 422 is attached to the upper header 23. As described later, wet steam SM1 is generated from the boiler water W2 in the heated water pipe 22, and dried in the air-water separator 7 to become dry steam SM2. The dry steam SM2 is sent to the steam header 50 through the steam delivery line L5. In the first condensed water electrical conductivity sensor 422, among the steam SM3 accumulated in the steam header 50, the backflow steam SM4 that has flowed back through the steam delivery line L5 and the steam takeout line L4 due to malfunction of the steam check valve 95 It is a sensor which detects the electric conductivity of the condensed water which stays in the upper header 23 among the condensed water W5 produced by being cooled. The first condensed water electrical conductivity sensor 422 is electrically connected to the control device 10. The detection value of the first condensed water electrical conductivity sensor 422 is transmitted to the control device 10 as a detection signal. The electrode portion of the first condensed water electrical conductivity sensor 422 will be described later.

  The lower header 24 is disposed below the boiler body 21. The lower header 24 is configured by, for example, an annular container. Lower ends of a plurality of water pipes 22 are connected and connected to the lower header 24. The end of the makeup water line L1 is connected to one of the side walls of the lower header 24. The other end of the side wall of the lower header 24 is connected to the end of the precipitation line L6. The combustion chamber 26 is constituted by a space surrounded by a plurality of water pipes 22.

  The burner 27 heats the inside of the boiler body 21 by combustion. The burner 27 is disposed at the upper central portion of the boiler body 21. The burner 27 is configured to include a fuel injection nozzle and an air supply nozzle (both not shown). The burner 27 injects fuel from the fuel injection nozzle toward the combustion chamber 26 of the boiler main body 21 and supplies air from the air supply nozzle to the inside of the boiler main body 21 to burn the fuel.

  The water level detector 28 is a device capable of continuously detecting the water level of the boiler water W2 stored in the water pipe 22 (boiler main body 21). The water level detector 28 is electrically connected to the control device 10. A detection signal of the boiler water W2 detected by the water level detector 28 is transmitted to the control device 10.

  In the present embodiment, the water level detector 28 is a continuous level sensor, and for example, a capacitive sensor, a pressure sensor, an ultrasonic sensor, or the like is used. In FIG. 3, an example in which a capacitance type sensor is provided as the water level detector 28 is shown. The water level detector 28 has a water level detection cylinder 28 a and an electrode rod 28 b. The upper end portion of the water level detection cylinder 28a is connected to the upper header 23 via a connection line. The lower end portion of the water level detection cylinder 28a is connected to the lower header 24 via a connection line. The water level detection cylinder 28 a has the upper end connected to the upper header 23 and the lower end connected to the lower header 24 so that the boiler water W 2 is stored at a water level equal to that of the water pipe 22. The water level detector 28 measures the capacitance between the electrode rod 28b and the water level detection cylinder 28a by using the insulating film coated on the surface of the electrode rod 28b as a dielectric, so that the water level detection cylinder 28a It is possible to detect the water level of the boiler water W2 in contact with the electrode rod 28b. The water level detector 28 can continuously detect the change in the water level of the boiler water W2 inside the water level detection cylinder 28a by the change in the measured capacitance.

  The fuel supply line L2 is a line for supplying the burner 27 with the fuel F burned by the burner 27. The upstream end of the fuel supply line L2 is connected to a fuel F supply source (not shown). The downstream end of the fuel supply line L2 is connected to the burner 27. A fuel supply valve 92 is provided in the fuel supply line L2. The fuel supply valve 92 is a valve that adjusts the amount of fuel supplied to the burner 27. The fuel supply valve 92 can open and close the fuel supply line L2. Opening and closing of the fuel supply valve 92 is controlled by a drive signal from the control device 10.

  The steam takeout line L4 is a line for taking out the wet steam SM1 generated from the boiler water W2 in the water pipe 22 from the upper header 23 and introducing the wet steam SM1 into the steam-water separator 7. The upstream end of the steam extraction line L4 is connected to the upper surface of the upper header 23 of the boiler body 21. The downstream end of the steam extraction line L4 is connected to the upper side of the side of the steam-water separator 7.

  The steam-water separator 7 is a device for separating the wet steam SM1 introduced from the upper header 23 through the steam take-out line L4 into dry steam SM2 and moisture (hereinafter also referred to as “separated water W4”). As described above, the separated water W4 separated by the air-water separator 7 is also a part of the boiler water W2.

  The steam delivery line L5 is a line for delivering the dried steam SM2 separated by the steam-water separator 7 toward the steam header 50. The upstream end of the steam delivery line L5 is connected to the upper surface of the steam-water separator 7. The downstream end of the steam delivery line L5 is connected to the steam header 50.

  The steam delivery line L5 is provided with a main steam valve 94, a steam check valve 95, and a steam header 50 in this order from the steam / water separator 7 toward a load device (not shown). The main steam valve 94 is a valve capable of manually switching the open / close state of the steam delivery line L5. The steam check valve 95 is a valve that prevents the backflow of the steam SM 3 from the steam header 50. The steam header 50 is equipment for collecting dry steam SM2 from a plurality of installed boilers (not shown) and distributing the collected steam SM3 to a steam using facility (not shown).

  The precipitation line L6 is a line for flowing the separated water W4 separated by the air-water separator 7 toward the lower header 24 of the boiler main body 21. The upstream end of the precipitation line L6 is connected to the lower part of the air-water separator 7. The downstream end of the precipitation line L6 is connected to the lower header 24. The connection part J2 is provided in the precipitation line L6, and the boiler water electrical conductivity sensor 421 is attached to the lower header 24 side of the connection part J2. Moreover, the 2nd condensed water electrical conductivity sensor 423 is attached to the air-water separator 7 side of the connection part J2.

  The boiler water electrical conductivity sensor 421 is a sensor that detects the electrical conductivity of the boiler water W2 (separated water W4). The electrode portion of the boiler water conductivity sensor 421 is located at a height lower than the water surface of the boiler water W2 of the water pipe 22. The boiler water conductivity sensor 421 is electrically connected to the control device 10. The detection value of the boiler water conductivity sensor 421 is transmitted to the control device 10 as a detection signal.

  The second condensed water electrical conductivity sensor 423 is generated among the steam SM3 accumulated in the steam header 50 by the malfunction of the steam check valve 95, by cooling the backflow steam SM4 flowing back through the steam delivery line L5. It is a sensor which detects the electric conductivity of the condensed water which stays in the air-water separator 7 among the condensed water W5. The second condensed water electrical conductivity sensor 423 is electrically connected to the control device 10. The detection value of the second condensed water electrical conductivity sensor 423 is transmitted to the control device 10 as a detection signal.

  The first condensed water electrical conductivity sensor 422 and the second condensed water electrical conductivity sensor 423 are provided with an electrode portion 430 having a first electrode 431 and a second electrode 432, as shown in FIGS. 5 and 6. . The first electrode 431 and the second electrode 432 of the first condensed water electrical conductivity sensor 422 and the first electrode 431 and the second electrode 432 of the second condensed water electrical conductivity sensor 423 have the same configuration. There is. Therefore, in the following description, only the first electrode 431 and the second electrode 432 of the first condensed water electrical conductivity sensor 422 will be described.

  The first electrode 431 has a substantially cylindrical shape. A central portion in the longitudinal direction of the first electrode 431 has a large diameter portion 434 having a large inner diameter and an outer diameter. The large diameter portion 434 is fixed in the lower wall portion of the upper header 23. One end in the longitudinal direction of the first electrode 431 protrudes above the upper surface of the lower wall of the upper header 23. One end in the longitudinal direction of the first electrode 431 has a notch 437 (see FIG. 6) extending in the direction from the one end in the longitudinal direction of the first electrode 431 to the insulating member 435 in the direction of the other end. In addition, a draining notch 438 is provided on the opposite side of the notch 437 in the radial direction in a cross sectional view. The drainage notch 438 is provided in a part of the first electrode 431 in the longitudinal direction.

  The other end in the longitudinal direction of the first electrode 431 protrudes below the lower surface of the lower wall portion of the upper header 23. A nut 433 is screwed into the other end. In the space surrounded by the inner surface of the large diameter portion 434, the insulating member 435 is filled and fixed. The second electrode 432 is a straight rod. The second electrode 432 is supported by the insulating member 435 and is fixed to the first electrode 431 in a positional relationship corresponding to the axial center position of the first electrode 431. One end of the second electrode 432 projects upward from the insulating member 435 as shown in FIG. 5 and is surrounded by one end of the first electrode 431.

  The condensed water W5 generated by cooling the back flow steam SM4 can flow from the notch 437 into the space 436 surrounded by one end of the first electrode 431, as shown by the arrow A. When the condensed water W5 present in the space 436 contacts the first electrode 431 and the second electrode 432, the electrical conductivity of the condensed water staying in the upper header 23 can be detected.

  In the case of the second condensed water electrical conductivity sensor 423, the axial centers of the first electrode 431 and the second electrode 432 have a positional relationship extending horizontally. That is, the electrode portion of the second condensed water electrical conductivity sensor 423 is attached horizontally to the vertically-lined precipitation line L6. The electrode unit in the attached state protrudes inside the precipitation line L6, and the notch 437 is located above. As a result, the condensed water W5 flowing into the space 436 from the notch 437 temporarily contacts the first electrode 431 and the second electrode 432, so that the condensed water W staying in the air-water separator 7 Electrical conductivity can be detected. The condensed water W5 can flow out of the space 436 through the drainage notch 438 as indicated by the arrow B.

  The upstream end of the blow line L3 is connected to the connection portion J2. Blow line L3 is a line for discharging separated water W4 (boiler water W2) flowing through precipitation line L6 (falling pipe) to the outside of boiler 20 through connection portion J2. A blow valve 93 is provided in the blow line L3. The blow valve 93 can open and close the blow line L3. Opening and closing of the blow valve 93 is controlled by a drive signal from the control device 10. By opening the blow valve 93, the separated water W4 (boiler water W2) flowing through the precipitation line L6 (the precipitation pipe) is discharged to the outside.

  Next, with reference to FIG. 4, functions relating to control of the boiler system 1 of the present embodiment will be described. Control device 10 controls each part in boiler system 1 of this embodiment. The control device 10 is electrically connected to each measurement device in the boiler system 1 and receives measurement information from each measurement device. Further, the control device 10 is electrically connected to the feed water pump 6 and controls the feed water pump 6 so as to feed the makeup water W1 toward the boiler 20 according to the water level of the boiler water W2 in the boiler main body 21.

  Further, the control device 10 includes a control unit 100 and a memory unit 110. The control unit 100 includes a valve control unit 101, a timer unit 102, and a corrosion inhibitor addition control unit 103.

  The valve control unit 101 controls the open / close state of the fuel supply valve 92 and the blow valve 93. The timer unit 102 counts the operation stop time and the like after the boiler 20 stops the operation.

  The control unit 100 supplies makeup water W1 to the boiler body 21 so that the water amount of the boiler water W2 stored in the boiler body 21 becomes the preset reference water storage amount X at the time of startup of the boiler 20. , Control the feed water pump 6. As a result, the water amount of the boiler water W2 stored in the boiler body 21 is maintained at the preset reference water storage amount X.

  The corrosion inhibitor addition control unit 103 suppresses the chemical supply processing of adding the corrosion inhibitor to the boiler water W2 stored in the boiler main body 21 so that the corrosion suppression water quality can suppress the corrosion of the boiler main body 21 It can be implemented by the agent addition device 81. As a result, the water quality of the boiler water W2 maintained at the standard water storage amount X is maintained so as to be the corrosion-suppressed water quality.

  The memory unit 110 stores a control program for performing the operation of the boiler system 1 of the present embodiment, predetermined parameters, various tables, and the like. In the present embodiment, the memory unit 110 may be, for example, a first predetermined value to be compared with a detected value of the first condensed water electrical conductivity sensor 422 or a detected value of the second condensed water electrical conductivity sensor 423, a boiler water, A second predetermined value to be compared with the difference between the detected value of the electrical conductivity sensor 421 and the detected value of the first condensed water electrical conductivity sensor 422 is stored. In addition, the memory unit 110 is, for example, a detected water level value at the time of stopping the operation of the boiler 20, or the replenishment water W1 supplied to the boiler main body 21 necessary for achieving corrosion suppression water quality capable of suppressing corrosion of the boiler main body 21. The amount of corrosion inhibitor added that corresponds to the amount is stored. The memory unit 110 also stores the water storage amount of the boiler water W2 corresponding to the detected water level value of the boiler water W2.

  Next, with reference to FIG. 3, the operation of the boiler system 1 of the present embodiment will be briefly described. First, the makeup water W1 is supplied to the water supply tank 5 from a supply source (not shown). At this time, the hardness component of the makeup water W1 supplied from the supply source is removed by the water softening apparatus 3 and becomes the softening water. And the softening water produced | generated by the hard water softening apparatus 3 is stored by the water supply tank 5 as a supplementary water (boiler water supply) W1. Here, the fuel supply valve 92 and the blow valve 93 are in the closed state.

  Next, the feed water pump 6 is operated, whereby the makeup water W1 (boiler feed water) stored in the feed water tank 5 is sent out toward the lower header 24 of the boiler body 21 through the makeup water line L1. And the replenishment water W1 supplied to the boiler 20 is stored as the boiler water W2 in the lower header 24 and each water pipe 22.

  The feed water pump 6 supplies the makeup water W1 to the boiler body 21 such that the water amount of the boiler water W2 stored in the boiler body 21 becomes the preset reference water storage amount X. The makeup water W1 supplied to the boiler main body 21 is stored as the boiler water W2 in the lower header 24 and each water pipe 22. When the makeup water W1 is supplied to the lower header 24 and each water pipe 22, the corrosion inhibitor addition control unit 103 corresponds to the makeup water W1 so that the corrosion suppression water quality can suppress the corrosion of the boiler main body 21. The corrosion inhibitor addition device 81 is controlled to supply the corrosion inhibitor. Thereby, the pH value of the boiler water W2, the amount of acid consumption (pH 8.3), or the silica concentration is maintained so as to be the corrosion-suppressed water quality.

  Next, fuel is supplied to the burner 27 by switching the fuel supply valve 92 from the closed state to the open state. By the burner 27 being ignited, the burner 27 starts combustion.

  The boiler water W2 stored in the lower header 24 and each water pipe 22 ascends the inside of each water pipe 22 while being heated by the burner 27 through the water pipe wall, and then becomes the wet steam SM1. Then, the wet steam SM1 generated inside each water pipe 22 is collected in the upper header 23 and introduced into the steam separator 7 via the steam takeout line L4.

  The wet steam SM1 introduced into the steam-water separator 7 is separated into a dry steam SM2 and a separation water W4. The dried steam SM2 separated by the steam-water separator 7 is collected in the steam header 50 through the steam delivery line L5 by switching the main steam valve 94 from the closed state to the open state. The steam SM3 collected in the steam header 50 is supplied to a steam using device (not shown). The separated water W4 separated by the air-water separator 7 is returned to the lower header 24 through the precipitation line L6.

At the time of the operation stop of such a boiler 20, for example, when the seal performance of the steam check valve 95 is deteriorated due to aged deterioration or the like, the steam may flow back from the steam header 50 to the boiler main body 21. The back flow steam SM4 is stored as condensed water W5 in the boiler main body 21. At the startup of the boiler 20, makeup water W1 is supplied to the boiler main body 21 so as to be the amount of the boiler water W2 of the reference storage amount X set in advance. Then, the corrosion inhibitor in an amount corresponding to the amount of water supplied to the supplied makeup water W1 is supplied to the boiler water W2.
The boiler 20 according to the present invention performs the process of the flowchart shown in FIG. 7 as follows.

  Next, an operation of detecting the condensed water W5 generated from the backflow steam SM4 by the first condensed water electrical conductivity sensor 422 from the time of the operation stop in the boiler 20 of the present embodiment to the time of the next start will be described. FIG. 7 is a flowchart showing a processing procedure of backflow detection in the boiler 2 according to the first embodiment of the present invention.

  As shown in FIG. 7, in step ST11, the boiler system 1 stops the operation of the boiler 20. The timer unit 102 starts counting the operation stop time after the operation of the boiler 20 is stopped.

  In step ST12, the control device 10 measures whether or not the operation stop time of the boiler 20 measured by the timer unit 102 has elapsed a predetermined time. The predetermined time is, for example, one hour. When the operation stop time of the boiler 20 has passed a predetermined time (YES), the process proceeds to step ST13. On the other hand, when the operation stop time of the boiler 20 does not elapse for a predetermined time (NO), the process returns to step ST12.

  In step ST13, the control device 10 determines the presence or absence of the backflow of steam to the stopped boiler 20 of the plurality of boilers, based on the detection value of the first condensed water electrical conductivity sensor 422. Specifically, the electric conductivity of the condensed water W5 staying in the upper header 23 is detected by the first condensed water electric conductivity sensor 422, and it is judged whether or not the detected value exceeds a first predetermined value, The control device 10 performs. The control device 10 determines that there is a backflow of steam to the boiler 20 when the detection value of the first condensed water electrical conductivity sensor 422 exceeds the first predetermined value. Here, the first predetermined value is, for example, 3 μS / cm. A very small amount of boiler water W2 remains in the dried steam SM2 generated by the steam-water separator 7, and the boiler water W2 contained in the wet steam SM1 adheres to the inner wall of the steam takeout line L4. doing. Therefore, an electric conductivity of about 5 μS / cm is detected in the condensed water W5 generated from the backflow steam SM4. When the backflow steam SM4 does not flow into the upper header 23 and the condensed water W5 is not in contact with the first electrode 431 and the second electrode 432, the detection value of the first condensed water electrical conductivity sensor 422 is It becomes 0 μS / cm.

  When the detection value of the first condensed water electrical conductivity sensor 422 exceeds the first predetermined value (YES), the control device 10 is generating the backflow of steam to the stopped boiler 20 The process of the control device 10 proceeds to step ST14. On the other hand, when the detected value of the first condensed water electrical conductivity sensor 422 does not exceed the first predetermined value (NO), the process of the control device 10 returns.

  In step ST14, the control device 10 performs processing for the backflow of steam. Specifically, the following four processing patterns are exemplified.

  (1) The control device 10 controls the corrosion inhibitor addition device 81 of the boiler 20 via the corrosion inhibitor addition control unit 103 when it is determined that the backflow of steam to the boiler 20 is present. More specifically, the corrosion inhibitor addition control unit 103 calculates the stop time water storage amount Y of the boiler water W2 stored in the boiler main body 21 based on the detected water level value of the boiler water W2 when the operation of the boiler 20 is stopped. Then, the corrosion inhibitor addition control unit 103 calculates the stop time shortage water amount Z of the boiler water obtained by subtracting the stop time water storage amount Y from the preset reference water storage amount X. Then, the corrosion inhibitor addition control unit 103 adds the corrosion inhibitor in an amount necessary for the water quality of the boiler water W2 of the stop shortage water amount Z to become the corrosion suppression water quality when the target boiler 20 is started next time. Thus, the chemical supply processing is performed in the corrosion inhibitor addition device 81. Thereby, even if the steam flows back to the boiler main body 21, the water quality of the boiler water W2 is maintained to be the corrosion-suppressed water quality.

  (2) When it is determined that the backflow of steam to the boiler 20 is present, the control device 10 controls the number control device 53 so as to raise the priority of the boiler 20. As a result, the time until the boiler 20 which has been shut down is put into the combustion state next time is shortened, and the dilution state of the boiler water W2 is eliminated early.

  (3) The control device 10 controls the burner 27 so as to forcibly burn in the boiler 20 when it is determined that the backflow of steam to the boiler 20 is present. As a result, concentration of the boiler water W2 of the boiler 20 that has been shut down proceeds, and the water quality reaches the corrosion-suppressed water quality.

  (4) A notification device (not shown) so as to prompt the administrator of the boiler system 1 to perform maintenance on the steam check valve 95 when the control device 10 determines that there is a backflow of steam to the boiler 20. To notify of the occurrence of abnormality via

  According to the boiler 20 which concerns on 1st Embodiment mentioned above, the following effects are acquired, for example.

  The boiler 20 in the present embodiment constitutes a boiler group consisting of a plurality of boilers, and includes a boiler body 21 having a plurality of water pipes 22, a burner 27 for heating the inside of the boiler body 21 by combustion, and an upper header 23 And a steam / water separator 7 communicated with the lower header 24, a steam check valve 95 provided in a steam delivery line L5 connected to the steam / water separator 7, a plurality of water pipes 22, and a steam check valve 95 Of the plurality of boilers 20 based on the detection values of the condensed water electric conductivity sensors 422 and 423 for detecting the electric conductivity of the condensed water W5 generated in the region between and the condensed water electric conductivity sensors 422 The control device 10 as a determination unit that determines the presence or absence of the backflow of the steam SM4 to the stopped boiler 20 is included.

  Therefore, the stay of the condensed water W5 generated from the backflow steam SM4 can be easily detected from the detection values of the condensed water electrical conductivity sensors 422 and 423. Thereby, the control device 10 can start processing for the backflow of steam.

  In addition, the control device 10 as the determination unit stops when the detected value of the first condensed water electrical conductivity sensor 422 or the detected value of the second condensed water electrical conductivity sensor 423 exceeds a first predetermined value. It is determined that the backflow of the steam SM4 to the existing boiler 20 is occurring. Therefore, by setting the first predetermined value to be an extremely small value, the condensed water W5 staying in the upper header 23 can be reliably detected, and the determination accuracy of the vapor backflow can be enhanced.

  Next, a boiler according to a second embodiment will be described based on FIG. FIG. 8 is a flowchart showing the backflow detection processing procedure in the boiler 2 according to the second embodiment of the present invention.

  The boiler by 2nd Embodiment differs in the process by the control apparatus 10 from the process by the control apparatus 10 of the boiler 20 by 1st Embodiment. That is, based on the difference between the detection value of the boiler water electrical conductivity sensor 421 and the detection value of the first condensed water electrical conductivity sensor 422, the control device 10 stops the stopped boiler 20 of the plurality of boilers 20. It is determined whether or not there is a backflow of the steam SM4. About the structure of those other than this, since it is the same as that of the structure of the boiler 20 by 1st Embodiment, it abbreviate | omits description about the same structure.

  Thereafter, the condensed water W5 generated from the backflow steam SM4 is detected by the boiler water electrical conductivity sensor 421 and the first condensed water electrical conductivity sensor 422 from the time of operation stop in the boiler 20 of the present embodiment to the time of next start The operation to be performed will be described.

  As shown in FIG. 8, in step ST21, the boiler system 1 stops the operation of the boiler 20. The timer unit 102 starts counting the operation stop time after the operation of the boiler 20 is stopped.

  In step ST22, the control device 10 measures whether or not the operation stop time of the boiler 20 measured by the timer unit 102 has elapsed a predetermined time. The predetermined time is, for example, one hour. If the operation stop time of the boiler 20 has passed a predetermined time (YES), the process proceeds to step ST23. On the other hand, when the operation stop time of the boiler 20 does not elapse for a predetermined time (NO), the process returns to step ST22.

  In step ST23, the electric conductivity of the condensed water W5 staying in the upper header 23 is detected by the first condensed water electric conductivity sensor 422. And control device 10 judges whether the detected value of the 1st condensed water electrical conductivity sensor 422 exceeded the 1st predetermined value. Here, the first predetermined value is, for example, 3 μS / cm. A very small amount of boiler water W2 remains in the dried steam SM2 generated by the steam-water separator 7, and the boiler water W2 contained in the wet steam SM1 adheres to the inner wall of the steam takeout line L4. doing. Therefore, an electric conductivity of about 5 μS / cm is detected in the condensed water W5 generated from the backflow steam SM4. When the backflow steam SM4 does not flow into the upper header 23 and the condensed water W5 is not in contact with the first electrode 431 and the second electrode 432, the detection value of the first condensed water electrical conductivity sensor 422 is It becomes 0 μS / cm.

  When the detected value of the first condensed water electrical conductivity sensor 422 exceeds the first predetermined value (YES), the process of the control device 10 proceeds to step ST24. On the other hand, when the detected value of the first condensed water electrical conductivity sensor 422 does not exceed the first predetermined value (NO), the process of the control device 10 returns.

  In step ST24, the control device 10 acquires a detection value (A value) of the boiler water electrical conductivity sensor 421. Further, the control device 10 acquires a detection value (B value) of the first condensed water electrical conductivity sensor 422. Then, the control device 10 calculates the difference (A−B) of the detected values. Then, the process of the control device 10 proceeds to step ST25.

  In step ST25, the control device 10 determines whether the difference (A−B) in the detection values calculated in step ST24 is smaller than the second predetermined value. Here, the second predetermined value is, for example, 1795 μS / cm. The detected value of the boiler water electrical conductivity sensor 421 is the separated water W4 (carried over boiler water W2) in the air / water separator 7 during the boiler operation, and about 2000 μS / cm when the enrichment is sufficiently high Indicates the value of.

  During boiler operation, the degree of enrichment is higher from the lower header 24 toward the water surface of the water pipe 22. Therefore, when a predetermined time passes after the boiler is stopped, the entire boiler water W2 mixes and the boiler water conductivity The detected value of the sensor 421 is slightly reduced to show a value of about 1800 μS / cm. On the other hand, as described above, the detection value of the first condensed water electrical conductivity sensor 422 shows a value of about 5 μS / cm when the condensed water W5 generated from the backflow steam SM4 is staying, When the condensed water W5 does not stay, it becomes 0 μS / cm. Therefore, when backflow is occurring, the difference between the detection value of the boiler water electrical conductivity sensor 421 and the detection value of the first condensed water electrical conductivity sensor 422 (for example, 1795 μS / cm) is a backflow. It becomes smaller than the difference (for example, 1800 μS / cm) when it is not present.

  Therefore, when the difference between the detected values (A−B) falls below the second predetermined value (YES), the control device 10 determines that the backflow of steam to the stopped boiler 20 is occurring. Then, the processing of the control device 10 proceeds to step ST26. On the other hand, when the difference between the detection values (A−B) is equal to or greater than the second predetermined value (NO), the process of the control device 10 returns. In step ST26, the control device 10 performs the same process as the process for the backflow of steam in step ST14 of the first embodiment.

According to the boiler 20 according to the second embodiment described above, for example, the following effects can be obtained.
As described above, when the difference between the detection value of the boiler water electrical conductivity sensor 421 and the detection value of the first condensed water electrical conductivity sensor 422 falls below the second predetermined value, the control device 10 as the determination unit It is determined that the backflow of the steam SM4 to the stopped boiler 20 is occurring. Therefore, it is possible to reliably detect the condensed water W5 staying in the upper header 23 by control different from that of the first embodiment, and to improve the determination accuracy of the vapor backflow.

Hereinabove, the preferred embodiments of the present invention have been described. However, the present invention can be implemented in various forms without being limited to the above-described embodiment.
For example, in the first embodiment, the detection value of the first condensed water electrical conductivity sensor 422 is used to determine the vapor backflow, but is not limited thereto. For example, instead of the detection value of the first condensed water electrical conductivity sensor 422, the detected value of the second condensed water electrical conductivity sensor 423 may be used for determination of vapor backflow. In this case, the condensed water W5 staying in the air-water separator 7 is detected to determine the vapor backflow.

  In addition, the configuration of the electrode unit included in the first condensed water electrical conductivity sensor 422 and the second condensed water electrical conductivity sensor 423 is not limited to the configuration of the electrode unit 430. Other configurations can be adopted as long as there is no problem in the inflow and the outflow of the condensed water W5 to the electrode portion.

2 boiler group 7 air / water separator 10 control unit (judging unit)
23 upper header 24 lower header 20 boiler 21 boiler main body 22 water pipe 27 burner 95 steam check valve 421 boiler water electrical conductivity sensor 422 first condensed water electrical conductivity sensor (condensed water electrical conductivity sensor)
423 Second Condensed Water Conductivity Sensor (Condensed Water Conductivity Sensor)
L5 Steam delivery line W2 Boiler water W5 Condensed water SM4 Backflow steam (steam)

Claims (3)

A boiler constituting a boiler group consisting of a plurality of boilers, wherein
A boiler body having an upper header, a lower header, and a plurality of water pipes connected to the upper header and the lower header;
A burner which heats the inside of the boiler body by combustion;
A steam separator communicated with the upper header and the lower header;
A steam check valve provided in a steam delivery line connected to the steam-water separator;
A condensed water electrical conductivity sensor for detecting the electrical conductivity of condensed water generated in the area between the plurality of water pipes and the steam check valve;
A determination unit that determines the presence or absence of a backflow of steam to the boiler when the boiler is stopped based on a detection value of the condensed water electrical conductivity sensor. The condensed water electric conductivity sensor detects the electric conductivity of the condensed water staying in the upper header or the electric conductivity of the condensed water staying in the air-water separator,
The said determination part determines that the backflow of the vapor | steam to the stopped boiler has generate | occur | produced, when the detected value of the said condensed water electrical conductivity sensor exceeds 1st predetermined value. Boiler. The boiler further includes a boiler water conductivity sensor that detects the conductivity of the boiler water,
The condensed water electrical conductivity sensor detects the electrical conductivity of condensed water staying in the upper header,
The determination unit is configured to determine the backflow of steam to the stopped boiler when the difference between the detected value of the boiler water electrical conductivity sensor and the detected value of the condensed water electrical conductivity sensor falls below a second predetermined value. The boiler according to claim 1, wherein it is determined that is occurring.

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