JP5980630B2 - Steam heating system - Google Patents

Description

  The present invention relates to a steam superheating system.

  Saturated steam is widely used as a heat source because of its simple temperature control and easy heat transport. Since the temperature of the saturated steam is determined by the steam pressure, the temperature of the saturated steam can be controlled by adjusting the pressure of the saturated steam.

  Conventionally, a steam supply system has been proposed in which saturated steam discharged from a boiler is heated using a superheater and then sent to a steam-using device (see, for example, Patent Documents 1 and 2).

  In patent document 1, the superheated steam generator provided with the steam boiler which heats with a burner and generate | occur | produces saturated steam, and the superheater which makes the saturated steam generated with the steam boiler superheated steam by the exhaust gas discharged | emitted from a steam boiler Is disclosed.

  In Patent Document 2, in a boiler having a tube group structure composed of a large number of heat transfer tube groups, a steam superheater having a heat transfer steam tube is provided between the upstream can body and the downstream can body to transfer heat. A boiler that makes saturated steam passing through a steam pipe into superheated steam is disclosed.

JP 2008-32235 A JP 2000-193205 A

  The superheated steam generator as in Patent Document 1 and the boiler as in Patent Document 2 both introduce saturated steam generated from the boiler into the superheater and superheat it to form superheated steam. However, the saturated steam generated from the boiler contains some water. Moreover, impurities such as ions such as sodium ions and chloride ions may be present in the water supplied to the boiler. Therefore, when saturated steam with a certain level of moisture is sent to the superheater and heated by the superheater, the inner surface of the flow pipe (heat transfer pipe) through which the saturated steam in the superheater passes is contained in the water supplied to the boiler Impurities may adhere as evaporation residues. If evaporation residue adheres to the inner surface of the heat transfer tube, the amount of heat transfer from the heat source that superheats the saturated steam to the saturated steam that passes through the heat transfer tube of the superheater decreases, and the superheater stably superheats the saturated steam. May not be possible.

  This invention is made | formed in view of the above, Comprising: It suppresses that the amount of heat transfer to saturated steam at the time of superheated saturated steam with a superheater can suppress, and can overheat saturated steam stably. An object is to provide a steam superheating system.

  The steam superheating system according to the present invention includes a steam generator that heats water to generate steam, a steam superheater that superheats the steam generated by the steam generator, and the steam from the steam generator to the steam. A saturated steam supply path for sending air to the superheater; and a superheated steam supply path for sending superheated steam superheated by the steam superheater to a steam-using facility, and stopping the operation of the steam superheater In this case, a cleaning medium is supplied to a flow path through which the steam passes in the steam superheater to clean the steam superheater.

  As a preferred aspect of the present invention, an operation measuring means for measuring the operation time of the steam generator is provided, the quality of water supplied to the steam generator, and the operation of the steam generator measured by the operation measuring means The concentration of water in the steam generator is determined from the time, the dryness of the steam generated in the steam generator is estimated from the concentration, the dryness of the steam, and the operation time of the steam generator The amount of evaporation residue generated in the steam superheater is calculated from the amount of evaporation of the water obtained from the above. If the amount of evaporation residue generated exceeds a set value, the steam of the steam superheater passes through It is preferable to supply the cleaning medium to the flow path.

  As a preferred aspect of the present invention, there is provided an operation measuring means for measuring an operation time of the steam generating device, and a concentration detecting means for detecting the concentration of the water in the steam generating device, and the concentration detecting means The dryness of the steam generated in the steam generator is estimated from the detected concentration, and the water obtained from the dryness of the steam and the operation time of the steam generator measured by the operation measuring means The amount of evaporation residue generated in the steam superheater is calculated from the amount of evaporation of the steam, and when the amount of evaporation residue generated exceeds a set value, the steam of the steam superheater passes through the flow path through the steam. It is preferred to supply a cleaning medium.

  As a preferred aspect of the present invention, it is preferable that the cleaning medium is supplied into the steam superheater after a predetermined time has elapsed for the steam generator or the steam superheater.

  As a preferred embodiment of the present invention, the cleaning medium is preferably steam or water.

  According to the present invention, when the operation of the steam superheater is stopped, the cleaning medium is supplied to the flow path through which the steam in the steam superheater passes and the steam superheater is cleaned. It can suppress that the amount of heat transfer to saturated steam at the time of superheated saturated steam with a vessel decreases, and can stably superheat saturated steam.

It is a figure showing a schematic structure of a steam superheating system concerning a 1st embodiment of the present invention. It is a figure which shows schematic structure of the steam superheating system which concerns on the 2nd Embodiment of this invention. It is a figure which shows schematic structure of the steam superheating system which concerns on the 3rd Embodiment of this invention. It is a figure which shows an example of the other structure of a steam superheating system.

  DESCRIPTION OF EMBODIMENTS Hereinafter, modes for suitably carrying out the present invention (hereinafter referred to as embodiments) will be described in detail. In addition, this invention is not limited by the content described in the following embodiment. In addition, constituent elements in the embodiments described below include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the constituent elements disclosed in the embodiments described below may be appropriately combined, or may be appropriately selected and used.

[First Embodiment]
<Steam superheating system>
A steam superheating system according to a first embodiment of the present invention will be described. FIG. 1 is a diagram showing a schematic configuration of a steam superheating system according to the first embodiment of the present invention. In FIG. 1, the saturated steam and the superheated steam are simultaneously shown when the saturated steam is superheated by the superheater and when the inner surface of the heat transfer tube of the superheater is cleaned. As shown in FIG. 1, a steam superheating system 10 according to the present embodiment is a system that supplies steam to a steam-using device (load device) 11 that operates using steam as a heating source, a power source, and the like. The steam superheating system 10 according to the present embodiment includes a boiler (steam generating device) 12, a steam supply path L11, a superheater (steam superheating device) 13, and a control device 14.

(boiler)
The boiler 12 generates saturated steam St1 by various heat source methods. As the boiler 12, various types such as a combustion boiler and an electric boiler can be used. In the case of the combustion type, the boiler 12 evaporates can water in the can body using combustion heat generated when the fuel is burned as a heat source, and generates saturated steam St1. In this case, as the fuel, for example, a gas fuel such as city gas, propane gas, or biogas, or a liquid fuel such as heavy oil or kerosene is used. In the case of the combustion type, the boiler 12 includes, for example, a once-through boiler, a furnace tube fired boiler, a water tube boiler, and the like. In the case of an electric type, the boiler 12 evaporates can water in the can body using an electric heater or the like as a heat source to generate saturated steam St1.

  In the present embodiment, the saturated steam St1 is a steam in a range from a steam containing slightly liquid water to a 100% dry steam.

(Steam supply route)
The steam supply path L <b> 11 is a steam supply line for sending saturated steam St <b> 1 generated in the boiler 12 from the boiler 12 to the steam using device 11. In the present embodiment, the steam supply path L11 includes a saturated steam pipe (saturated steam supply path) L12 and a superheated steam pipe (superheated steam supply path) L13. The steam supply path L11 may include a flow rate adjusting valve for adjusting the flow rate of the steam flowing in the path.

  The saturated steam pipe L12 connects the steam outlet of the boiler 12 and the steam inlet of the superheater 13 and supplies the saturated steam St1 to the superheater 13.

  The superheated steam pipe L <b> 13 connects the steam outlet of the superheater 13 and the steam inlet of the steam using device 11, and supplies superheated steam St <b> 2 to the steam using device 11.

(Superheater)
The superheater 13 superheats the saturated steam St1 generated by the boiler 12 to form superheated steam St2. The superheater 13 is a shell and tube heat exchanger (multi-tubular heat exchanger). The superheater 13 has the shell (body) side of the superheater 13 as the primary side, the superheat medium 21 is circulated through the body, and the tube (heat transfer tube) 23 side is the secondary side. Saturated steam St1, which is steam, is circulated. As the superheating medium 21, for example, high-temperature heat medium oil from the heat medium boiler, combustion gas discharged from the boiler 12, or the like is used. Moreover, when using the high pressure steam whose temperature is higher than the saturated steam St1 supplied from other boilers as the superheat medium 21, the superheater 13 superheats the heat transfer pipe 23 with the heat transfer pipe 23 side as the primary side. The medium 21 is circulated, and the saturated steam St1 is circulated in the body with the body side as the secondary side. That is, the high pressure side is circulated to the heat transfer tube 23 side. The passage for supplying the superheating medium 21 into the superheater 13 is provided with a flow rate adjusting valve V11 in the middle thereof, and the supply amount of the superheating medium 21 supplied into the superheater 13 is adjusted by the flow rate adjusting valve V11.

  The superheater 13 uses the superheated medium 21 supplied to the fuselage side as a heat source, and circulates the saturated steam St1 fed from the saturated steam pipe L12 in the heat transfer pipe 23 so that the inner surface of the heat transfer pipe 23 (superheated surface). ) To evaporate the saturated steam St1 to obtain superheated steam St2.

  The superheater 13 is connected to the steam discharge pipe L14. The steam discharge pipe L <b> 14 is a line for discharging the saturated steam St <b> 1 used for cleaning the superheater 13. The steam discharge pipe L14 is provided with a discharge valve 24 in the middle thereof. Further, as will be described later, the steam discharge pipe L14 is connected to a cleaning medium discharge pipe L15 that discharges the saturated steam St1 passing through the superheated steam pipe L13. In the present embodiment, the steam discharge pipe L14 is connected to the cleaning medium discharge pipe L15, but the steam discharge pipe L14 is not connected to the cleaning medium discharge pipe L15, and the saturated steam St1 passing through the steam discharge pipe L14. May be discharged as it is.

  The heating amount of the superheater 13 is controlled by the control device 14. The amount of heating in the superheater 13 corresponds to the amount of heat given to the saturated steam St1 passing through the superheater 13. The amount of heating in the superheater 13 can be increased or decreased by adjusting the supply amount (flow rate), temperature, and the like of the superheating medium 21 supplied into the superheater 13 by the control device 14. As the amount of heating in the superheater 13 increases, the amount of heat imparted to the saturated steam St1 increases, so the degree of superheat of the superheated steam St2 increases.

(Sensor etc.)
The steam superheating system 10 according to the present embodiment includes various sensors in the boiler 12, the steam supply path L11, and the like. These sensors are electrically connected to the control device 14. The steam superheating system 10 according to the present embodiment includes a pressure sensor 25 and a steam temperature sensor 26 in the steam supply path L11, and a concentration sensor (concentration detection means) 27 and a pressure inside the can inside the boiler 12. A sensor (pressure detection means) 28 is provided.

  The pressure sensor 25 is provided in the saturated steam pipe L12 and detects the pressure in the saturated steam pipe L12.

  The steam temperature sensor 26 is provided in the superheated steam pipe L13 and detects the temperature of the superheated steam St2 passing through the superheated steam pipe L13.

  The concentration sensor 27 is provided in the boiler 12 and detects the concentration multiple (concentration) of the can water in the boiler body of the boiler 12. In addition, the concentration of can water means the ratio by which the impurities in the can water are concentrated when the boiler 12 is operated for a predetermined time. The concentration sensor 27 detects, for example, electric conductivity of can water (1 / electric resistance of can water) [mS / m (milli Siemens per meter)]. Since the can water in the boiler 12 has higher ion content and becomes easier to conduct electricity as the concentration of the can water increases, the electric conductivity increases. The concentration sensor 27 detects the concentration of the can water in the boiler 12 using this principle.

  The can body pressure sensor 28 is provided in the boiler body of the boiler 12 and measures the pressure inside the boiler body of the boiler 12.

  The pressure sensor 25, the vapor temperature sensor 26, the concentration sensor 27, and the can body pressure sensor 28 each transmit an electrical signal corresponding to the detection result to the control device 14.

  The steam superheating system 10 according to the present embodiment is provided with a three-way valve 29 in the superheated steam pipe L13. The three-way valve 29 is connected to the cleaning medium discharge pipe L15. The three-way valve 29 is controlled by the control device 14, and sends superheated steam St2 passing through the superheated steam pipe L13 to the steam using device 11, or discharges saturated steam St1 through the cleaning medium discharge pipe L15 as described later. Switch the steam flow path.

(Control device)
The control device 14 controls each part of the steam superheating system 10 according to the present embodiment. The control device 14 includes, for example, various sensors attached to various portions of the steam superheating system 10 according to the present embodiment, such as a pressure sensor 25, a steam temperature sensor 26, a concentration sensor 27, and a can body pressure sensor 28. And an electrical signal corresponding to the detection result is input. Moreover, the control apparatus 14 outputs a control signal to each part, such as the superheater 13, based on the various input signals input from various sensors, and controls these. Moreover, the control apparatus 14 has the measuring device (operation measurement means) 30 which measures operation time, such as the boiler 12 and the superheater 13. FIG.

  By the way, since the dryness of the saturated steam St1 sent to the superheater 13 is generally about 99.5%, the saturated steam St1 contains some water and has some moisture. Moreover, since the soft water from which hardness, such as calcium and magnesium, was normally removed by the water softener is supplied to the boiler 12, the water supplied to the boiler 12 (hereinafter referred to as water supply to the boiler 12). Contains sodium ions, chloride ions and the like (hereinafter referred to as “impurities”). In addition, the sodium ion contained in the water supply to the boiler 12 is discharge | released in water supply with respect to cations, such as calcium and magnesium removed by a water softener. The water softener is composed only of cation exchange resin. When water used for water supply to the boiler 12 (hereinafter referred to as raw water) is passed through a water softener, the cation exchange resin takes in cations such as calcium ions and magnesium ions in the water. Then, the cation exchange resin discharges sodium ions into the water instead of the incorporated cations. When such impurities contained in the can water are contained in the saturated steam St1, they are discharged from the boiler 12 along with the saturated steam St1 and supplied to the superheater 13. When the saturated steam St1 having a certain degree of wetness is heated by the superheater 13, sodium chloride or the like is crystallized on the evaporation surface side of the heat transfer tube 23 and adheres as an evaporation residue.

  When the evaporation residue adheres to the inner surface of the heat transfer tube 23, the superheater 13 reduces the amount of heat transfer from the heat source that superheats the saturated steam St1 to the saturated steam St1 that passes through the heat transfer tube 23, and stably heats the saturated steam St1. It may not be possible. Therefore, the control device 14 supplies the cleaning medium to the heat transfer tube 23 when the supply of the superheater 21 to the superheater 13 is stopped and the operation of the superheater 13 is stopped.

  The control device 14 estimates the dryness of the saturated steam St1, and uses the estimated dryness value of the saturated steam St1, and uses the estimated value of the dryness of the saturated steam St1 to cause evaporation residue caused by impurities contained in the saturated steam St1. May be calculated, and the cleaning medium may be supplied into the superheater 13 in accordance with the amount of evaporation residue generated. Further, the control device 14 may supply the cleaning medium into the superheater 13 according to the operation time of the boiler 12 or the superheater 13 without estimating the dryness of the saturated steam St1.

  As the operation time of the boiler 12 becomes longer, the concentration of impurities in the can water increases due to repeated evaporation, and the bubbling of the can water in the can tends to increase. In the boiler 12, when the foaming of the can water increases, a phenomenon called so-called carry-over occurs in which part of the can water is mixed into the steam, and the dryness of the saturated steam St1 is reduced. For this reason, the boiler 12 discharges all the can water in the boiler 12 when the operation of the boiler 12 is finished, for example, when the concentration of the can water exceeds the allowable value or the operation time exceeds the set time. Then, all the can water is replaced with fresh water, and the dryness of the saturated steam St1 is kept within an allowable range. In general, during operation of the boiler 12, a portion of the can water is discharged and replaced with fresh water while the boiler 12 is operated so that the concentration of the can water is maintained at or below an allowable value. Concentration blow (intermittent blow) operation is automatically performed to keep the dryness of the saturated steam St1 within an allowable range.

  When the operation time of the boiler 12 becomes longer, the concentration of the can water proceeds and the dryness of the saturated steam St1 decreases. However, the operation time of the boiler 12 when the can water is concentrated to the same concentration, the water supply to the boiler 12 It depends on the water quality. When the raw water contains a large amount of hardness such as magnesium and calcium, for example, water such as ground water, and the raw water contains water containing a large amount of chloride ions, the amount of impurities contained in the initial water supply increases (electric conduction) Higher degree). Therefore, even if the operation time of the boiler 12 is short, the concentration of the can water proceeds and the dryness of the saturated steam St1 decreases. Therefore, the water quality (electrical conductivity) of water supplied to the boiler 12 needs to be inspected and acquired in advance in order to estimate the dryness of the saturated steam St1, or measured using the concentration sensor 27 or the like. There is. In addition, what is necessary is just to use the total operation time from the last all blows typically as the operation time of the boiler 12. In this case, the operation time of the boiler 12 is, for example, 1 hour when operated at 100% load for 1 hour, 0.5 hour when operated at 50% load for 1 hour, Just add up the time.

  Thus, the dryness of the saturated steam St1 tends to be lower as the concentration of the can water inside the boiler 12 is higher. In particular, the degree of dryness of the saturated steam St1 tends to decrease because the concentration of the can water inside the boiler 12 increases as the operating time of the boiler 12 increases. Therefore, the dryness of the saturated steam St1 is obtained using the quality of water supplied to the boiler 12 and the operation time of the boiler 12 or the concentration of can water detected by the concentration sensor 27. Moreover, the operation time of the boiler 12 measured with the measuring device 30 of the control apparatus 14 can be used for the operation time of the boiler 12. FIG.

  Therefore, as an example, the control device 14 estimates the dryness of the saturated steam St1 from the quality of the water supplied to the boiler 12 and the operation time of the boiler 12, and uses the estimated dryness of the saturated steam St1 to heat transfer tubes. A case where the amount of evaporation residue generated on the inner surface of 23 is calculated will be described.

  The control device 14 uses the water quality of the water supplied to the boiler 12 and the operation time of the boiler 12 as parameters of the dryness of the saturated steam St1, and from the water quality of the water supplied to the boiler 12 and the operation time of the boiler 12 Obtain the concentration of canned water. The control device 14 obtains the operation time of the boiler 12 in consideration of the load when the boiler 12 is operated. And the control apparatus 14 estimates the dryness of saturated steam St1 from the quality of the water supply to the boiler 12, and the concentration of the obtained can water.

  The control device 14 shows the correlation between the quality of the water supplied to the boiler 12, the concentration of the can water estimated from the operation time of the boiler 12 as described above, and the dryness of the saturated steam St1 estimated from these. Information is stored as a map. The control device 14 estimates the dryness of the saturated steam St1 from the quality of the water supplied to the boiler 12 and the concentration of the can water estimated from the operation time of the boiler 12, using a map stored in advance. .

  Based on the ratio of the water in the saturated steam St1 thus calculated and the concentration of impurities contained in the moisture in the saturated steam St1 calculated as described above, the control device 14 uses the evaporation residue attached to the inner surface of the heat transfer tube 23. The generation amount of can be calculated.

  Further, as a method for accurately estimating the dryness of the saturated steam St1, the concentration of the can water actually detected by the concentration sensor 27 may be used. Next, the control device 14 estimates the dryness of the saturated steam St1 from the concentration of the can water actually detected by the enrichment sensor 27, and uses the estimated dryness of the saturated steam St1 to use the heat transfer tube 23. The case where the generation amount of the evaporation residue adhering to the inner surface is calculated will be described.

  As described above, the control device 14 stores, as a map, information indicating the correlation between the concentration of the can water and the dryness of the saturated steam St1 estimated from the concentration of the can water. The controller 14 uses this map to estimate the dryness of the saturated steam St1 generated in the boiler 12 from the enrichment of the can water detected by the enrichment sensor 27. After estimating the dryness of the saturated steam St1, the controller 14 determines the degree of dryness of the superheater 13 from the dryness of the saturated steam St1 and the amount of evaporation of can water obtained from the operation time of the boiler 12 in the same manner as described above. The amount of evaporation residue attached to the inner surface of the heat transfer tube 23 can be calculated.

  Further, the degree of dryness of the saturated steam St <b> 1 tends to decrease as the pressure in the boiler body of the boiler 12 decreases and the combustion load increases because the boiling state of the boiler body changes depending on the pressure in the boiler body of the boiler 12. Therefore, when estimating the dryness of the saturated steam St1, the control device 14 further increases the accuracy of the estimation of the dryness of the saturated steam St1, as a parameter of the dryness of the saturated steam St1, the boiler water of the boiler 12 In addition to the degree of enrichment, the pressure in the boiler of the boiler 12, the combustion amount of the boiler 12, etc. may be used for estimation. At this time, the operation time of the boiler 12 may be calculated based on the detection result of the combustion amount of the boiler 12 or the like.

  The control device 14 controls the flow rate control valve V11 and the like so as to clean the inner surface, which is the superheated surface of the heat transfer tube 23 of the superheater 13, according to the amount of evaporation residue calculated as described above. In the present embodiment, saturated steam St1 is used as the cleaning medium. Specifically, when the controller 14 determines that the amount of evaporation residue generated exceeds a predetermined set value, the operation of the steam using device 11 is stopped thereafter, or the steam using device 11 generates the superheated steam St2. When it is no longer used, the flow control valve V11 is closed and the supply of the superheat medium 21 to the superheater 13 is stopped. Next, the control device 14 operates the three-way valve 29 to switch the flow path in the direction in which the saturated steam St1 fed from the superheater 13 flows to the cleaning medium discharge pipe L15, and the discharge provided in the steam discharge pipe L14. Open the valve 24. The saturated steam St1 sent from the boiler 12 into the heat transfer tube 23 flows while dissolving the evaporation residue adhering to the inner surface of the heat transfer tube 23 of the superheater 13. The saturated steam St1 discharged from the superheater 13 to the superheated steam pipe L13 is discharged to the outside through the cleaning medium discharge pipe L15. A part of the saturated steam St1 in the superheater 13 is discharged from the superheater 13 through the steam discharge pipe L14 and the cleaning medium discharge pipe L15. Cleaning of the inner surface of the heat transfer tube 23 of the superheater 13 is performed for a predetermined time. The predetermined time is set in advance based on the amount of evaporation residue generated on the inner surface of the heat transfer tube 23. After the predetermined time has elapsed, the control device 14 closes the discharge valve 24 and operates the three-way valve 29 to switch the flow path in the direction in which the saturated steam St1 flows from the boiler 12 to the steam using device 11. Thereafter, the control device 14 opens the flow rate control valve V11 and starts supplying the superheating medium 21 to the superheater 13, and the superheater 13 prepares for the saturated steam St1 to be supplied from the boiler 12.

  The inner surface of the heat transfer tube 23 may be cleaned when the boiler 12 starts operating or when the steam using device 11 starts operating. When the controller 14 determines that the amount of evaporation residue generated on the inner surface of the heat transfer tube 23 exceeds a predetermined set value, the heat transfer tube at the start of the operation of the next boiler 12 or the operation of the steam using device 11. What is necessary is just to wash | clean the inner surface of 23. FIG.

  In addition, in this embodiment, since the to-be-heated surface of the heat exchanger tube 23 is an inner surface, the case where the inner surface of the heat exchanger tube 23 was cleaned was demonstrated, However, The superheated medium 21 in the superheater 13 and the saturated steam which is a to-be-heated medium When the flow path to St1 is opposite, the superheated surface is the outer surface of the heat transfer tube 23. Therefore, when the flow path of the superheating medium 21 and the saturated steam St1 is reversed, the saturated steam St1 flows on the outer surface side of the heat transfer tube 23 so as to clean the outer surface of the heat transfer tube 23. In addition, the connection portion of the superheater 13 with the steam discharge pipe L14 is provided on the bottom surface of the trunk so that the saturated steam St1 including evaporation residue can be easily extracted from the superheater 13.

  In addition, when the quality of the water supplied to the boiler 12 is obtained in advance, and the maximum value of the concentration of can water allowed based on the quality of the water supplied to the boiler 12 is set as a predetermined threshold, the control device 14 Alternatively, it may be detected only whether or not the concentration of the can water detected by the concentration sensor 27 exceeds a predetermined threshold value. When the controller 14 determines that the concentration of the can water detected by the concentration sensor 27 exceeds a predetermined threshold, the controller 14 stops the supply of the superheat medium 21 to the superheater 13 and operates the superheater 13. Is stopped, saturated steam St1 is supplied into the superheater 13 as a cleaning medium, and the inner surface of the heat transfer tube 23 is cleaned.

  Up to this point, the control device 14 estimates the dryness of the saturated steam St1, and uses the estimated dryness of the saturated steam St1 to calculate the generation amount of evaporation residue attached to the inner surface of the heat transfer tube 23. Although demonstrated, the control apparatus 14 does not estimate the dryness of saturated steam St1, and stops supply of the superheat medium 21 to the superheater 13 according to the operation time of the boiler 12 or the superheater 13, and serves as a cleaning medium. The saturated steam St1 may be supplied into the superheater 13. Specifically, the control device 14 stops the supply of the superheating medium 21 to the superheater 13 after the operation time of the boiler 12 or the superheater 13 has passed a predetermined set time, and performs cleaning in the superheater 13. Saturated steam St1 is supplied as a medium. Thereby, the evaporation residue adhering to the inner surface of the heat transfer tube 23 is dissolved in moisture in the saturated steam St1, and the inner surface of the heat transfer tube 23 is cleaned.

  The predetermined set time is a period of time during which the saturated steam St1 is superheated by the superheater 13 after supplying the saturated steam St1 as a cleaning medium into the superheater 13 to clean the inner surface of the heat transfer tube 23. Until time passes. At this time, the timing at which the cleaning medium is supplied into the heat transfer tube 23 is before the superheater 13 is superheated with the superheater 13 before the superheater 13 is supplied and the operation of the superheater 13 is started. .

  As described above, the steam superheating system 10 according to the present embodiment supplies the saturated steam St1 as the cleaning medium into the heat transfer pipe 23 when the supply of the superheat medium 21 to the superheater 13 is stopped, and the heat transfer pipe The evaporation residue adhering to the inner surface of the heat transfer tube 23 is removed to clean the inner surface of the heat transfer tube 23. Thereby, the steam superheating system 10 which concerns on this embodiment suppresses that the heat transfer efficiency to saturated steam St1 at the time of superheating saturated steam St1 with the superheater 13 suppresses, and superheats saturated steam St1 stably. be able to.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of invention. For example, in the steam superheating system 10 according to the present embodiment, the case where the saturated steam St1 generated in the boiler 12 is used as the cleaning medium has been described, but the cleaning medium is not limited to the saturated steam St1. As the cleaning medium, in addition to the saturated steam St1, for example, steam sent from the outside can be used as well.

  In the present embodiment, the saturated steam St1 generated in one boiler 12 is supplied to the superheater 13 via the saturated steam pipe L12. However, the present invention is not limited to this. The saturated steam St1 generated in the boiler 12 may be supplied to the superheater 13.

[Second Embodiment]
A steam superheating system according to a second embodiment of the present invention will be described. The steam superheating system according to this embodiment relates to the first embodiment except that the cleaning medium used in the steam superheating system 10 according to the first embodiment shown in FIG. 1 is changed from saturated steam St1 to water. Since it is the same as that of a steam superheating system, the overlapping description is omitted.

  FIG. 2 is a diagram showing a schematic configuration of a steam superheating system according to the second embodiment of the present invention. In FIG. 2, when the saturated steam St1 is superheated by the superheater 13 and when the inner surface of the heat transfer tube 23 is cleaned, the saturated steam St1, the superheated steam St2, the superheated medium 21 and water used as the cleaning medium are used. Show at the same time. As shown in FIG. 2, the steam superheating system 40 according to the present embodiment includes a three-way valve 41 and a cleaning medium supply pipe L21 in the steam superheating system 10 (see FIG. 1) according to the first embodiment. It is a thing. The three-way valve 41 is provided in the saturated steam pipe L12 and is connected to the cleaning medium supply pipe L21. The cleaning medium supply pipe L21 is a line for supplying water 42 to the saturated steam pipe L12 from the outside.

  When water 42 is used as the cleaning medium, for example, water such as tap water or ground water, soft water supplied to the boiler 12, blow water of the boiler 12, distilled water, or pure water is used as the water 42. Can do.

  The three-way valve 41 is controlled by the control device 14. The control device 14 operates the three-way valve 41 to adjust the saturated steam St1 passing through the saturated steam pipe L12 or the water 42 supplied from the cleaning medium supply pipe L21 to the superheater 13.

  When the controller 14 determines that the amount of evaporation residue generated exceeds a predetermined set value and cleans the inner surface of the heat transfer tube 23 of the superheater 13, when the operation of the steam using device 11 stops thereafter, or When the steam using device 11 stops using the superheated steam St2, the flow control valve V11 is closed and the supply of the superheat medium 21 to the superheater 13 is stopped. Next, the control device 14 operates the three-way valve 29 to switch the flow path in the direction in which the saturated steam St1 fed from the superheater 13 flows to the cleaning medium discharge pipe L15, and the discharge provided in the steam discharge pipe L14. Open the valve 24. Thereafter, the three-way valve 41 is operated to switch the flow path in the direction in which the water 42 supplied from the cleaning medium supply pipe L21 flows to the superheater 13. The water 42 supplied from the cleaning medium supply pipe L21 flows while melting the evaporation residue adhering to the inner surface of the heat transfer tube 23 of the superheater 13. The water 42 discharged from the superheater 13 to the superheated steam pipe L13 is discharged to the outside through the cleaning medium discharge pipe L15. A part of the water 42 in the superheater 13 is discharged from the superheater 13 to the outside through the steam discharge pipe L14 and the cleaning medium discharge pipe L15. The inner surface of the heat transfer tube 23 is cleaned for a predetermined time. After the predetermined time has elapsed, the control device 14 operates the three-way valve 41 to switch the flow path in the direction in which the saturated steam St1 flows from the boiler 12 to the superheater 13. Then, the control device 14 closes the discharge valve 24 and operates the three-way valve 29 to switch the flow path in the direction in which the saturated steam St1 flows from the boiler 12 to the steam using device 11. Thereafter, the control device 14 opens the flow rate adjustment valve V11 and starts supplying the superheat medium 21 to the superheater 13, and the superheater 13 prepares for the saturated steam St1 to be supplied from the boiler 12.

  In this embodiment, when the inner surface of the heat transfer tube 23 is cleaned, the flow path is switched by operating the three-way valve 29, and then the flow path is switched by operating the three-way valve 41. However, the three-way valves 29 and 41 may be operated simultaneously to switch the flow path.

  Further, after cleaning the inner surface of the heat transfer tube 23, the control device 14 operates the three-way valve 41 to switch the flow path in the direction in which the saturated steam St 1 flows from the boiler 12 to the superheater 13, and then operates the three-way valve 29. Before switching the flow path of the saturated steam St1, it is preferable to supply the saturated steam St1 to the superheater 13 for a predetermined time to remove the water 42 remaining in the heat transfer tube 23. When the superheating medium 21 is supplied to the superheater 13 with the water 42 remaining in the heat transfer tube 23, the water 42 in the heat transfer tube 23 evaporates and evaporates due to impurities contained in the water 42 remaining in the heat transfer tube 23. Residues may be generated. Therefore, after supplying the water 42 into the heat transfer tube 23, the saturated steam St1 is sent into the heat transfer tube 23 to remove the water 42 remaining in the heat transfer tube 23. Further, since the saturated steam St1 can be used as a cleaning medium, the evaporation residue remaining on the inner surface of the heat transfer tube 23 can be removed. In addition, when removing the water 42 remaining in the heat transfer tube 23, air or the like may be used in addition to the saturated steam St1.

  Moreover, since saturated steam St1 can also be used as a cleaning medium, after supplying either saturated steam St1 or water 42 to the superheater 13, the other may be supplied to the superheater 13 for cleaning.

  Thus, according to the steam superheating system 40 according to the present embodiment, even when water 42 is used as the cleaning medium, the evaporation residue attached to the inner surface of the heat transfer tube 23 is removed to remove the inner surface of the heat transfer tube 23. Can be washed. For this reason, also in the steam superheating system 40 according to the present embodiment, similarly to the steam superheating system 10 according to the first embodiment, the reduction of the superheating efficiency of the saturated steam St1 is suppressed, and the saturated steam St1 is stably heated. can do.

[Third Embodiment]
A steam superheating system according to a third embodiment of the present invention will be described. The steam superheating system according to the present embodiment is the first embodiment except that the superheater of the steam superheating system according to the first embodiment shown in FIG. 1 is changed from a heat exchange type superheater to an electric superheater. Since it is the same as that of the steam superheating system which concerns on a form, the overlapping description is abbreviate | omitted.

  FIG. 3 is a diagram showing a schematic configuration of a steam superheating system according to the third embodiment of the present invention. FIG. 3 shows the saturated steam St1 and the superheated steam St2 simultaneously when the saturated steam St1 is superheated by the superheater and when the superheater is cleaned. As shown in FIG. 3, the steam superheating system 50A according to the present embodiment is an electric type instead of the heat exchange type superheater 13 having the configuration of the steam superheating system 10 (see FIG. 1) according to the first embodiment. The superheater 51 is provided. The superheater 51 includes an electric heater 52 inside the main body. Heat generated when an electric current is passed through the electric heater 52 is used as a heat source for heating the saturated steam St1 to superheated steam St2. The heating amount of the electric heater 52 is adjusted by the power source 53. The power supply 53 is provided outside the main body and is controlled by the control device 14. The control device 14 can adjust the amount of heating in the superheater 51 by controlling the voltage of the power supply 53, and can adjust the degree of superheat of the superheated steam St2 to a predetermined degree of superheat. In the present embodiment, the electric heater 52 is used as the heating means for heating the saturated steam St1, but the present invention is not limited to this. For example, a heating coil, a heating element that generates heat by electromagnetic induction, and the like. May be used.

  When the controller 14 determines that the amount of evaporation residue adhering to the superheated surface of the electric heater 52 in the superheater 51 exceeds a predetermined set value, and cleaning the surface of the electric heater 52, Thereafter, when the operation of the steam using device 11 is stopped or when the steam using device 11 stops using the superheated steam St2, the energization to the electric heater 52 is stopped. Next, the control device 14 operates the three-way valve 29 to switch the flow path in the direction in which the saturated steam St1 sent from the superheater 51 flows to the cleaning medium discharge pipe L15, and the discharge provided in the steam discharge pipe L14. Open the valve 24. The saturated steam St <b> 1 sent from the boiler 12 into the superheater 51 flows while melting the evaporation residue adhering to the surface of the electric heater 52 of the superheater 51. The saturated steam St1 discharged from the superheater 51 to the superheated steam pipe L13 is discharged to the outside through the cleaning medium discharge pipe L15. A part of the saturated steam St1 in the superheater 51 is discharged from the superheater 51 to the outside through the steam discharge pipe L14 and the cleaning medium discharge pipe L15. The surface of the electric heater 52 is cleaned for a predetermined time. After a predetermined time has elapsed, the control device 14 closes the discharge valve 24 and operates the three-way valve 29 to switch the flow path in the direction in which the saturated steam St1 flows from the boiler 12 to the steam using device 11, The superheater 51 is energized to prepare for the saturated steam St1 being fed from the boiler 12.

  The cleaning of the surface of the electric heater 52 may be performed at the start of the operation of the boiler 12 or the start of the operation of the steam using device 11 as in the steam superheating system 10 according to the first embodiment. When it is determined that the amount of evaporation residue generated on the surface of the electric heater 52 exceeds a predetermined set value, the control device 14 starts the operation of the next boiler 12 or starts the operation of the steam using device 11. The surface of 52 may be cleaned.

  Therefore, according to the steam superheating system 50A according to the present embodiment, even if the superheater is the electric superheater 51, the evaporation residue or the like attached to the surface of the electric heater 52 is removed, and the inside of the superheater 51 is removed. Can be washed. For this reason, also in the steam superheating system 50A according to the present embodiment, similarly to the steam superheating system 10 according to the first embodiment, the reduction of the superheating efficiency of the saturated steam St1 is suppressed, and the saturated steam St1 is stably heated. can do.

  In the present embodiment, the case where the saturated steam St1 generated in the boiler 12 is used as the cleaning medium has been described, but water is used as the cleaning medium as in the steam superheating system 40 according to the second embodiment of FIG. 42 may be used.

  In particular, when water 42 is used as the cleaning medium, it is preferable that the water 42 be efficiently supplied into the superheater 51. An example of another configuration of the steam superheating system when water 42 is used as the cleaning medium is shown in FIG. As shown in FIG. 4, the steam superheating system 50 </ b> B according to this embodiment includes a cleaning medium supply pipe L <b> 22 and a nozzle 55. The cleaning medium supply pipe L22 is a cleaning medium supply line for supplying water 42 from the outside, with the water outlet at the tip thereof being inserted into the superheater 51. The nozzle 55 is provided at the tip of the cleaning medium supply pipe L <b> 22 and injects water 42 into the superheater 51. The water 42 is supplied by the pump 56, and the supply amount of the water 42 is adjusted by the flow rate adjusting valve V12. By injecting the water 42 passing through the cleaning medium supply pipe L22 into the superheater 51 from the nozzle 55, the water 42 can be efficiently and widely supplied into the superheater 51. Thereby, since the evaporation residue adhering to the surface of the electric heater 52 can be efficiently dissolved in the water 42, the cleaning efficiency in the superheater 51 can be improved.

  Further, the steam superheating system 50B according to the present embodiment may clean the interior of the superheater 51 by supplying water 42 and saturated steam St1 as cleaning media into the superheater 51. The water 42 sprayed from the nozzle 55 is accompanied by the saturated steam St1 supplied into the superheater 51 and supplied to a wider range in the superheater 51, thereby further improving the cleaning efficiency in the superheater 51. be able to.

  In addition, the steam superheating system 50B according to the present embodiment supplies the water 42 and the saturated steam St1 separately to the inside of the superheater 51, but is not limited to this, and the saturated steam pipe L12 is used. The water 42 may be mixed with the saturated steam St1 and then supplied to the superheater 13.

  Moreover, in this embodiment, although the case where the superheater 51 was equipped with the electric heater 52 inside the main body was demonstrated, it is not limited to this, For example, it may provide the electric heater 52 outside the main body. It may be.

  As mentioned above, each structure of the steam superheating system 10, 40, 50A, 50B which concerns on said each embodiment is not limited to this, You may make it combine the structure in any one of said each embodiment suitably. Moreover, in each structure of the steam superheating system 10, 40, 50A, 50B which concerns on said each embodiment, although the superheater demonstrated the case of a heat exchange type superheater or an electrical superheater, it is limited to this. Various types other than the heat exchange type or the electric type can be used similarly.

10, 40, 50A, 50B Steam superheating system 11 Steam use equipment 12 Boiler (steam generator)
13, 51 Superheater (steam superheater)
DESCRIPTION OF SYMBOLS 14 Control apparatus 21 Superheated medium 23 Heat exchanger tube 24 Discharge valve 25 Pressure sensor 26 Steam temperature sensor 27 Concentration sensor (concentration detection means)
28 Can body pressure sensor (pressure detection means)
29, 41 Three-way valve 30 Measuring instrument (operation measuring means)
42 Water 52 Electric heater 53 Power supply 55 Nozzle 56 Pump L11 Steam supply path L12 Saturated steam piping (saturated steam supply path)
L13 Superheated steam piping (superheated steam supply route)
L14 Steam discharge pipe L15 Cleaning medium discharge pipe L21, L22 Cleaning medium supply pipe St1 Saturated steam St2 Superheated steam V11, V12 Flow control valve

Claims (3)

A steam generator for heating water to generate steam;
A steam superheater that superheats the steam generated by the steam generator;
A saturated steam supply path for sending the steam from the steam generator to the steam superheater;
A superheated steam supply path for sending superheated steam superheated by the steam superheater to a steam using facility;
Have
An operation measuring means for measuring the operation time of the steam generator is provided,
Obtaining the concentration of water in the steam generator from the quality of the water supplied to the steam generator and the operation time of the steam generator measured by the operation measuring means,
Estimating the dryness of the steam generated in the steam generator from the concentration,
From the degree of dryness of the steam and the amount of evaporation of the water obtained from the operating time of the steam generator, the amount of evaporation residue generated in the steam superheater is calculated,
When the operation of the steam superheater is stopped after the generation amount of the evaporation residue exceeds a set value , a cleaning medium is supplied to a flow path through which the steam in the steam superheater passes, A steam superheating system characterized in that the steam superheater is cleaned . A steam generator for heating water to generate steam;
A steam superheater that superheats the steam generated by the steam generator;
A saturated steam supply path for sending the steam from the steam generator to the steam superheater;
A superheated steam supply path for sending superheated steam superheated by the steam superheater to a steam using facility;
Have
Operation measuring means for measuring the operation time of the steam generator;
A concentration detection means for detecting the concentration of the water in the steam generator; and
Estimating the dryness of the steam generated in the steam generator from the enrichment detected by the enrichment detection means,
From the degree of dryness of the steam and the amount of evaporation of the water obtained from the operation time of the steam generator measured by the operation measuring means, the amount of evaporation residue generated in the steam superheater is calculated,
When the operation of the steam superheater is stopped after the generation amount of the evaporation residue exceeds a set value , a cleaning medium is supplied to a flow path through which the steam in the steam superheater passes, A steam superheating system characterized in that the steam superheater is cleaned . In claim 1 or 2 ,
The steam heating system, wherein the cleaning medium is steam or water.

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