JP6031945B2 - Steam recovery system - Google Patents

Description

  The present invention relates to a steam recovery system that recovers steam from a drain discharged from a load device that uses steam from a steam supply source such as a boiler as a heat source.

  In a system that uses steam as a heat source, the drain discharged from the load equipment is recovered and the heat is effectively used. For example, the recovered drain is returned to the steam supply source or used as a heat source for other equipment. I do. Moreover, as a method of effectively using heat, a method has been proposed in which steam is separated from drain using a flash tank and used as a heat source for another load device (see, for example, Patent Document 1).

  In Patent Document 1, when drain discharged from a plurality of finishing rolls as load devices is supplied to a flash tank, flash steam is generated because the pressure in the flash tank is lower than that of the finishing roll. The amount of steam used in the continuous washing machine is saved by supplying the flash steam to the continuous washing machine as the load device and using it. The drain from which the steam is separated in the flash tank is supplied to the boiler tank via the steam trap and used as hot water. Further, the water level in the flash tank is detected by the water level sensor, and the amount of flash steam sent from the flash tank to the continuous washing machine is adjusted according to the water level in the flash tank.

JP 2009-198038 A

  Here, since the drain supplied to the flash tank changes depending on the operating state of the load device, the state of the drain in the flash tank of the supplied drain also varies. For this reason, as described in Patent Document 1, even if the recovery amount of flash steam is adjusted based on the water level, there is a possibility that flash steam having a high dryness cannot be stably recovered from the flash tank. Therefore, there is room for further study in stably recovering flash steam having a high dryness from the flash tank.

  The present invention has been made in view of the above, and is a steam recovery system capable of stably recovering steam with a high degree of dryness from the separation unit and stably discharging drain from the separation unit. The purpose is to provide.

A steam recovery system according to the present invention recovers drain discharged from a load device, separates a flash vapor generated from the recovered drain, and is provided in the separation unit, and detects a pressure in the separation unit A pressure detection unit that is connected to the separation unit, and a steam discharge line that discharges the flash steam from the separation unit; and a discharge amount of the flash steam that is provided in the steam discharge line and that flows through the steam discharge line A steam control valve that controls the steam control valve based on a detection result of the pressure detection unit, and the control unit compares the detected pressure of the pressure detection unit with a set pressure. When the pressure detection unit is equal to or higher than the set pressure, the opening of the steam control valve is adjusted with the steam control valve opened according to the detected pressure. Adjust the emissions Gerhard steam, when the detected pressure is less than the set pressure, characterized by stopping the emission of the flash steam by closing the steam regulating valve.

  As a preferred aspect of the present invention, a water level detection unit that is provided in the separation unit and detects a water level of the drain in the separation unit, and a first drain discharge that is connected to the separation unit and discharges the drain from the separation unit. And a first drain adjustment unit that is provided in the first drain discharge line and adjusts a discharge amount of the drain flowing through the first drain discharge line, and the control unit is configured to control the water level detection unit. It is preferable to control the first drain adjustment unit based on the detection result to adjust the drain discharge amount.

  As a preferred aspect of the present invention, a temperature measurement unit that is provided in the separation unit and measures the temperature of the drain in the separation unit, and a second drain discharge that is connected to the separation unit and discharges the drain from the separation unit. And a second drain adjustment unit that is provided in the second drain discharge line and discharges the drain flowing through the second drain discharge line, and the control unit has a temperature of the drain that is set to a preset temperature. When it falls below, it is preferable to discharge | emit the said drain through the said 2nd drain discharge line by controlling the said 2nd drain adjustment part.

  According to the present invention, it is possible to recover the flash vapor with a stable pressure and dryness from the separation unit, and to adjust the amount of drain discharged from the separation unit according to the amount of drain flowing into the separation unit. Steam with high dryness can be stably recovered from the separation part, and drain can be stably discharged from the separation part.

It is a figure showing the schematic structure of the steam system provided with the steam recovery system concerning the embodiment of the present invention. It is a flowchart which shows an example of the procedure which controls a steam control valve. It is a flowchart which shows an example of the procedure which controls a 1st drain discharge valve. It is a flowchart which shows an example of the procedure which controls a 2nd drain discharge valve.

  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.

<Steam system>
A steam system including a steam recovery system according to an embodiment of the present invention will be described. FIG. 1 is a diagram illustrating a schematic configuration of a steam system including a steam recovery system according to an embodiment of the present invention. As shown in FIG. 1, the steam system 10 includes a boiler (steam supply source) 11, a steam header 12, a first load device 13, a water supply tank 14, a second load device 15, and a steam recovery system 16. It has.

  The boiler 11 is a steam supply source that generates steam 21 by various heat source methods. As the boiler 11, various types such as a combustion boiler and an electric boiler can be used. In the case of the combustion type, the boiler 11 generates steam by heating the can water in the can body using the heat of combustion when the fuel is burned as a heat source. When the boiler 11 is of the combustion type, 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 as the fuel. In the case of the combustion type, the boiler 11 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 11 generates steam by heating can water in the can body using an electric heater or the like as a heat source.

  The boiler 11 is connected to the steam header 12 by the first steam supply line L11. The first steam supply line L11 is a line that connects the boiler 11 and the steam header 12. The steam 21 is sent from the boiler 11 to the steam header 12 through the first steam supply line L11.

  The steam header 12 is for storing the steam 21. In this embodiment, although one boiler 11 is provided, it is not limited to this, You may provide the several boiler. In this case, steam supplied from a plurality of boilers is collected in the steam header 12.

  The steam header 12 is connected to the first load device 13 through the second steam supply line L12. The second steam supply line L12 is a line that connects the steam header 12 and the first load device 13. The steam 21 is sent to the first load device 13 through the second steam supply line L12.

  The steam header 12 is connected to the steam discharge line L21 through the third steam supply line L13. The third steam supply line L13 is a line connecting the steam header 12 and the steam discharge line L21. The steam 21 is sent from the steam header 12 through the third steam supply line L13 to the steam discharge line L21 and is sent to the second load device 15. The configuration of the steam discharge line L21 will be described later.

  The first load device 13 uses the steam 21 supplied from the steam header 12 as a heating source or a power source. In the present embodiment, the first load device 13 uses the steam 21 as a heating source. When the steam 21 passes through the steam supply passage in the first load device 13, it loses latent heat and partially condenses to become high-pressure and high-temperature drain (condensed water) 22. The first load device 13 includes one or more load devices such as a high pressure steam load device or an intermediate pressure steam load device. Accordingly, the drain 22 is generated from the steam 21 used as a heating source in one or more load devices such as a high pressure steam load device or a medium pressure steam load device.

  The first load device 13 is connected to the flash tank 23 by a drain supply line L14. The first load device 13 uses the steam 21 supplied from the second steam supply line L12 as a heating source, and discharges the drain 22 generated when the steam 21 is used to the drain supply line L14. Further, the drain supply line L14 is provided with a steam trap 24 in the middle of the drain supply line L14. The steam trap 24 allows only the drain 22 discharged from the first load device 13 to pass through. After passing through the steam trap 24, the drain 22 is supplied to the flash tank 23 and collected in the flash tank 23. The configuration of the flash tank 23 will be described later.

  In the drain supply line L14, a bypass line L15 is connected between the steam trap 24 and the flash tank 23. The bypass line L15 is a line connecting the drain supply line L14 and the first drain discharge line L22. The configuration of the first drain discharge line L22 will be described later. The bypass line L15 supplies the drain 22 to the water supply tank 14. The bypass line L15 is provided with an emergency discharge valve V11 in the middle of the bypass line L15. The emergency discharge valve V11 discharges the drain 22 flowing through the bypass line L15. The emergency drain valve V11 is opened when the water level in the flash tank 23 becomes higher than the normal setting range due to a failure of the first drain discharge valve V22, clogging in the first drain discharge line L22, or the like. The drain 22 is supplied to the water supply tank 14 through the bypass line L15 without passing through the flash tank 23.

  The water supply tank 14 is for storing the drain 22. The drain 22 in the water supply tank 14 is supplied to the boiler 11 as water 25 for generating steam 21. In addition, makeup water 26 is supplied to the water supply tank 14. When the water supplied to the boiler 11 is insufficient with only the drain 22 supplied to the water supply tank 14, makeup water 26 is supplied to the water supply tank 14 and supplied to the boiler 11 as water 25.

  The third steam supply line L13 is provided with a pressure reducing valve V12 in the middle of the third steam supply line L13. The steam 21 sent from the steam header 12 to the third steam supply line L13 passes through the pressure reducing valve V12 and then becomes the pressure reduced steam 27. The steam 21 flowing from the steam header 12 through the third steam supply line L13 becomes the decompressed steam 27 by the decompression valve V12, and then is sent to the second load device 15 through the steam discharge line L21.

  The second load device 15 uses a flash steam 28 discharged from the flash tank 23 and a decompressed steam 27 as a heating source or a power source. The second load device 15 includes one or more low-pressure steam load devices. In the present embodiment, the second load device 15 preferentially uses the flash steam 28 as a heating source over the decompressed steam 27. The second load device 15 uses the reduced-pressure steam 27 as a shortage when the amount of steam used in the second load device 15 is insufficient with only the flash steam 28.

(Steam recovery system 16)
The steam recovery system 16 includes a flash tank (separation unit) 23, a pressure sensor (pressure detection unit) 31, a water level detector (water level detection unit) 32, a temperature sensor (temperature measurement unit) 33, and a control device (control). Part) 34, steam discharge line L21, first drain discharge line L22, second drain discharge line L23, steam control valve (steam control part) V21, and first drain discharge valve (first drain control part). V22 and the 2nd drain discharge valve (2nd drain adjustment part) V23 are provided.

  The flash tank 23 collects the drain 22, and flash vapor 28 is generated from the collected drain 22. Since the pressure in the flash tank 23 is lower than that in the drain supply line L <b> 14, the flash vapor 28 is generated from the drain 22 supplied to the flash tank 23. The flash tank 23 is provided with a safety valve V24. When the pressure in the flash tank 23 becomes abnormally high, the safety valve V24 is opened to depressurize the flash tank 23.

  The steam discharge line L <b> 21 has one end connected to the flash tank 23 and the other end connected to the second load device 15. The steam discharge line L21 is a line for discharging the flash steam 28 from the flash tank 23. The steam discharge line L21 is provided with a pressure reducing valve V25 in the middle of the steam discharge line L21. The flash steam 28 passes through the steam discharge line L21 from the flash tank 23, is decompressed by the decompression valve V25, and is then sent to the second load device 15. The second load device 15 uses the low-pressure steam 27 together with the flash steam 28 as a heating source or a power source. The second load device 15 preferentially uses the flash steam 28, and uses the decompressed steam 27 as the steam that is not sufficient with the flash steam 28 alone. When the steam control valve V21 is closed and the flash steam 28 is not sent to the second load device 15, only the decompressed steam 27 is used as a heating source or a power source for the second load device 15.

  The steam control valve V21 is provided in the steam discharge line L21. The steam control valve V21 adjusts the flow rate of the flash steam 28 passing through the steam discharge line L21. The opening degree of the steam control valve V21 is adjusted based on a control signal sent from the control device 34.

  In the steam discharge line L21, a check valve V26 is provided between the steam control valve V21 and the pressure reducing valve V25. The check valve V26 prevents the reduced pressure steam 27 from flowing to the flash tank 23 side.

  In the steam discharge line L21, an internal pressure adjustment line L24 is connected between the flash tank 23 and the steam control valve V21. The internal pressure adjusting line L24 discharges a part of the flash steam 28 from the steam discharge line L21 to the outside. The internal pressure adjusting line L24 is provided with an internal pressure adjusting valve V28 in the middle of the internal pressure adjusting line L24. When the pressure in the steam discharge line L21 becomes a predetermined pressure or higher, the internal pressure control valve V28 opens the internal pressure control valve V28 to release the pressure to the outside, and the pressure in the steam discharge line L21 is higher than the predetermined pressure. It is used to adjust so that it does not become.

  The first drain discharge line L22 is connected to the water supply tank 14. The first drain discharge line L22 is a line for discharging the drain 22 from the flash tank 23. The drain 22 flows from the flash tank 23 into the water supply tank 14 through the first drain discharge line L22.

  The first drain discharge valve V22 is provided in the first drain discharge line L22. The first drain discharge valve V22 adjusts the discharge amount of the drain 22 flowing through the first drain discharge line L22. The opening degree of the first drain discharge valve V22 is adjusted based on a control signal sent from the control device 34.

  In the first drain discharge line L22, a check valve V27 is provided between the first drain discharge valve V22 and a position where the first drain discharge line L22 is connected to the bypass line L15. The check valve V27 prevents the drain 22 from flowing toward the flash tank 23 when flowing through the bypass line L15.

  The second drain discharge line L23 is provided in the middle of the first drain discharge line L22, specifically, between the flash tank 23 and the first drain discharge valve V22. The second drain discharge line L23 is a line for discharging the drain 22 from the flash tank 23 to the outside.

  The second drain discharge valve V23 is provided in the second drain discharge line L23. The second drain discharge valve V23 discharges the drain 22 flowing through the second drain discharge line L23. The opening and closing of the second drain discharge valve V23 is controlled based on a control signal sent from the control device 34.

  The pressure sensor 31 is provided in the flash tank 23. The pressure sensor 31 detects the pressure in the flash tank 23.

  The water level detector 32 is provided outside the flash tank 23. The water level detector 32 detects the water level of the drain 22 in the flash tank 23. The water level detector 32 includes a water level detection cylinder 41, a float 42, and a water level sensor 43. The water level detection cylinder 41 is provided on the side surface outside the flash tank 23. The water level detection cylinder 41 is communicated with the bottom of the flash tank 23 through a communication pipe 45 on the side surface on the lower side. Further, the water level detection cylinder 41 is communicated with the upper side of the flash tank 23 through the communication pipe 46 on the side surface on the upper side. The water level sensor 43 detects the water level of the drain 22 in the water level detection cylinder 41 by detecting the height of the float 42 provided in the water level detection cylinder 41. In the water level detection cylinder 41, the drain 22 flows from the flash tank 23 through the connection pipe 45 therein, so that the water level of the drain 22 in the flash tank 23 and the water level of the drain 22 in the water level detection cylinder 41 become substantially equal. For this reason, the water level sensor 43 can detect the water level of the drain 22 in the water level detection cylinder 41 by detecting the height of the float 42 in the water level detection cylinder 41.

  The temperature sensor 33 is provided in the flash tank 23. The temperature sensor 33 detects the temperature of the drain 22 in the flash tank 23.

  The pressure sensor 31, the water level detector 32, and the temperature sensor 33 each transmit an electrical signal corresponding to the detection result to the control device 34.

  The control device 34 controls each part of the steam recovery system 16. The control device 34 is a microcomputer including a CPU (Central Processing Unit) and a memory.The control device 34 is attached to various parts of the steam recovery system 16 such as the pressure sensor 31, the water level detector 32, and the temperature sensor 33. Various sensors are electrically connected, and electrical signals corresponding to the detection results of these various sensors are input to the control device 34 via an external input circuit, and the control device 34 receives inputs from the various sensors. Control signals are output to various valves such as the emergency discharge valve V11, the steam control valve V21, the first drain discharge valve V22, and the second drain discharge valve V23 based on the various electric signals thus controlled.

  Further, the control device 34 determines that the pressure in the flash tank 23 is higher than the set pressure and the water level of the drain 22 from the detection results of various sensors such as the pressure sensor 31, the water level detector 32, and the temperature sensor 33. It is detected that the temperature of the drain 22 is lower than the set temperature. In the present embodiment, the set pressure means that the pressure of the flash vapor 28 discharged from the flash tank 23 is stable, and a sufficient discharge pressure can be obtained when the drain 22 is discharged from the flash tank 23. The value of the pressure inside. Further, the set temperature is a lower limit value of the usable temperature at the drain 22 where it can be determined that the operation of the first load device 13 is in the initial stage of startup. The set range is equal to or lower than the upper limit water level at which the flash vapor 28 can be maintained at a predetermined dryness or higher, and the outlet of the drain 22 is sealed, and the drain 22 is discharged from the flash tank 23. In this case, the range is equal to or higher than the lower limit water level at which the flash vapor 28 is not discharged together with the drain 22. Moreover, preset temperature is about 60 degreeC, for example. The control device 34 transmits the detection result to the output unit 47 based on various electrical signals input from various sensors.

  The output unit 47 outputs operation information such as the steam recovery system 16 based on the detection result transmitted from the control device 34. The output unit 47 outputs operation information based on the detection result transmitted from the control device 34 to notify whether or not the operation state of the steam recovery system 16 or the like is abnormal. The output unit 47 can output driving information by, for example, lighting or blinking of a lamp or an alarm sound.

(Control of steam control valve V21)
The control device 34 outputs a control signal to the steam control valve V21 based on the pressure value in the flash tank 23 detected by the pressure sensor 31 to control the steam control valve V21, and the flash steam flowing through the steam discharge line L21. Adjust the 28 discharge amount.

  FIG. 2 is a flowchart showing an example of a procedure for controlling the steam control valve V21. As shown in FIG. 2, in step S <b> 11, the control device 34 detects the pressure in the flash tank 23 from the electrical signal corresponding to the pressure detected by the pressure sensor 31. After detecting the pressure in the flash tank 23, the control device 34 shifts the process to step S12. In step S12, the control device 34 compares the detection value detected by the pressure sensor 31 with the set pressure, and determines whether or not the detected pressure is equal to or higher than the set pressure. As a result of the comparison in step S12, if the detected value detected by the pressure sensor 31 is equal to or higher than the set pressure (step S12: Yes), the control device 34 shifts the process to step S13. In step S <b> 13, the control device 34 opens the steam control valve V <b> 21 and discharges the flash steam 28 from the flash tank 23. When the steam control valve V21 is already open, the opening degree is maintained as it is or the opening degree is adjusted according to the pressure in the flash tank 23 to maintain the state where the steam control valve V21 is open. .

  Moreover, as a result of the comparison in step S12, when the detected value detected by the pressure sensor 31 is less than the set pressure (step S12: No), the control device 34 shifts the process to step S14. In step S <b> 14, the control device 34 closes the steam control valve V <b> 21 and stops the discharge of the flash steam 28 from the flash tank 23.

  Thus, the steam recovery system 16 adjusts the opening degree of the steam control valve V21 according to the pressure in the flash tank 23. For this reason, the steam recovery system 16 can discharge the flash steam 28 and the drain 22 from the flash tank 23 at a stable pressure equal to or higher than a predetermined pressure. As a result, the steam recovery system 16 can supply the flash steam 28 having a stable pressure to the second load device 15.

  In addition, when the pressure in the flash tank 23 is lower than the set pressure, the steam recovery system 16 closes the steam control valve V21 and stops discharging the flash steam 28 from the flash tank 23. For this reason, the steam recovery system 16 can prevent the flash steam 28 from being discharged with the drain 22 accompanying the flash steam 28 when the flash steam 28 is discharged from the flash tank 23, thereby reducing the dryness of the flash steam 28. it can. As a result, the steam recovery system 16 can stably discharge the flash steam 28 having a high dryness from the flash tank 23 and supply it to the second load device 15. Further, since the steam recovery system 16 can obtain a stable pressure equal to or higher than a predetermined pressure as the discharge pressure of the drain 22 in the flash tank 23, the drain 22 is discharged from the flash tank 23 when the drain 22 is discharged from the flash tank 23. Can be discharged stably.

  When the load on the second load device 15 increases, a larger amount of flash vapor 28 than usual is sent from the flash tank 23 to the second load device 15, so that the pressure in the flash tank 23 is greatly lowered than usual, and the flash vapor 28 is increased. The flow rate at the time of discharge from the flash tank 23 also increases. Therefore, the drain 22 in the flash tank 23 is easily included in the flash vapor 28, and the drain 22 is easily discharged from the flash tank 23 along with the flash vapor 28. As a result, the dryness of the drain 22 discharged from the flash tank 23 may be reduced.

  In contrast, when the pressure in the flash tank 23 is equal to or higher than the set pressure, the steam recovery system 16 removes the flash steam 28 from the flash tank 23 while adjusting the opening of the steam control valve V21 according to the pressure in the flash tank 23. It is trying to discharge from. For this reason, even if the load in the second load device 15 increases and the supply amount of the flash steam 28 sent from the flash tank 23 to the second load device 15 fluctuates, the steam recovery system 16 changes the pressure in the flash tank 23. Is greatly reduced, and an increase in the flow rate when the flash vapor 28 is discharged from the flash tank 23 can be suppressed. For this reason, the steam recovery system 16 can suppress that the drain 22 is contained in the flash steam 28 and discharged together with the flash steam 28 when the flash steam 28 is discharged from the flash tank 23. . As a result, since the steam recovery system 16 can recover the flash steam 28 having a high dryness from the flash tank 23, the steam recovery system 16 supplies the flash steam 28 with a stable pressure to the second load device 15. Meanwhile, the flash steam 28 having a high dryness can be stably supplied to the second load device 15.

  Furthermore, when flash steam having a generally low dryness is supplied to the second load device 15, the amount of heat supplied to the second load device 15 may be reduced. Therefore, it is necessary to newly provide a device for removing the drain 22 accompanying the flash steam having a low dryness before supplying the flash steam having a low dryness to the second load device 15. On the other hand, the steam recovery system 16 can recover the flash steam 28 having a high degree of dryness from the flash tank 23, so that a device for removing the drain 22 accompanying the flash steam 28 is not provided separately. The flash steam 28 having a high dryness can be stably supplied from the flash tank 23 to the second load device 15.

(Control of first drain discharge valve V22)
The control device 34 outputs a signal to the first drain discharge valve V22 based on the water level value of the drain 22 in the flash tank 23 detected by the water level detector 32. And the control apparatus 34 controls the 1st drain discharge valve V22, adjusts the opening degree of the 1st drain discharge valve V22, and adjusts the discharge amount of the drain 22 which flows through the 1st drain discharge line L22.

  FIG. 3 is a flowchart showing an example of a procedure for controlling the first drain discharge valve V22. As shown in FIG. 3, in step S <b> 21, the control device 34 detects the water level of the drain 22 in the flash tank 23 from the electrical signal corresponding to the detection result of the water level detector 32. After detecting the water level of the drain 22 in the flash tank 23, the control device 34 shifts the process to step S22. In step S22, the control device 34 compares the detected value detected by the water level detector 32 with the set range. As a result of the comparison in step S22, when the detected value detected by the water level detector 32 is within the set range (step S22: Yes), the control device 34 shifts the process to step S23. In step S <b> 23, the control device 34 opens the first drain discharge valve V <b> 22 and discharges the drain 22 from the flash tank 23. Further, when the first drain discharge valve V22 is already open, the control device 34 maintains the opening degree of the first drain discharge valve V22 as it is or adjusts the opening degree of the first drain discharge valve V22 to perform the first operation. The state where the drain discharge valve V22 is open is maintained.

  When the detection value detected by the water level detector 32 is out of the set range as a result of the comparison in step S22 (step S22: No), the control device 34 shifts the process to step S24. In step S24, the control device 34 compares the detected value detected by the water level detector 32 with the upper limit value of the setting range. When the detection value detected by the water level detector 32 is higher than the upper limit value of the setting range as a result of the comparison at the water level detector 32 (step S24: Yes), the control device 34 proceeds to step S25. Let In step S25, the control device 34 makes the opening degree of the first drain discharge valve V22 larger than the current opening degree. When the first drain discharge valve V22 is closed, the control device 34 opens the first drain discharge valve V22.

  If the detection value detected by the water level detector 32 is not higher than the upper limit value of the setting range as a result of the comparison in step S24 (step S24: No), that is, the water level of the drain 22 in the flash tank 23 is the setting range. If it is lower than the lower limit value, the control device 34 shifts the processing to step S26. In step S26, the control device 34 reduces the opening of the first drain discharge valve V22 or closes the first drain discharge valve V22.

  Thus, the steam recovery system 16 adjusts the opening degree of the first drain discharge valve V22 according to the water level of the drain 22 in the flash tank 23. As a result, the steam recovery system 16 can discharge the drain 22 from the flash tank 23 in accordance with the fluctuation of the water level in the flash tank 23 in accordance with the load fluctuation of the first load device 13. As a result, the steam recovery system 16 can maintain the water level of the drain 22 in the flash tank 23 within the set range. Further, the steam recovery system 16 can adjust the amount of the drain 22 discharged from the flash tank 23 according to the supply amount of the drain 22 to the flash tank 23. When the steam usage of the first load device 13 fluctuates due to the fluctuation of the load of the first load device 13 and the flow rate of the drain 22 discharged from the first load device 13 increases, the amount of the drain 22 in the flash tank 23 increases. The water level in the flash tank 23 increases as the number increases. Therefore, when the water level of the drain 22 in the flash tank 23 is out of the set range, the steam recovery system 16 increases the opening of the first drain discharge valve V22 to increase the flash tank. The drain 22 in 23 can be discharged through the first drain discharge line L22.

(Control of second drain discharge valve V23)
Based on the detection result of the temperature sensor 33, the control device 34 outputs a signal to the second drain discharge valve V <b> 23 and discharges the drain 22 from the flash tank 23.

  FIG. 4 is a flowchart showing an example of a procedure for controlling the second drain discharge valve V23. In the following description, it is assumed that the first drain discharge valve V22 and the second drain discharge valve V23 are in a closed state when the operation of the steam system 10 is started, and the drain 22 is accumulated in the flash tank 23 to some extent. Assumes that As shown in FIG. 4, in step S <b> 31, the control device 34 detects the temperature of the drain 22 in the flash tank 23 from the electrical signal corresponding to the detection result of the temperature sensor 33. After acquiring the temperature of the drain 22 in the flash tank 23, the control device 34 shifts the process to step S32. In step S32, the control device 34 compares the detected value detected by the temperature sensor 33 with the set temperature, and determines whether or not the detected value detected by the temperature sensor 33 is lower than the set temperature.

  The drain 22 discharged when the operation of the first load device 13 is in the initial stage is low in temperature and often includes a large amount of impurities such as sludge and rust, air, and the like. Therefore, even if the drain 22 discharged in the initial operation of the first load device 13 is collected by the flash tank 23 and supplied to the water supply tank 14, it is difficult to use it in the boiler 11. Therefore, the set temperature needs to be higher than the lower limit value of the usable temperature in the drain 22.

  As a result of the comparison in step S32, when the detected value detected by the temperature sensor 33 is lower than the set temperature (step S32: Yes), the control device 34 shifts the process to step S33. In step S33, the control device 34 opens the second drain discharge valve V23 while keeping the first drain discharge valve V22 closed, and passes the drain 22 from the flash tank 23 through the second drain discharge line L23. To discharge. After discharging the drain 22 from the flash tank 23, the control device 34 shifts the process to step S31. In step S <b> 31, the control device 34 detects the temperature of the drain 22 in the flash tank 23 from the detection result of the temperature sensor 33.

  Moreover, as a result of the comparison in step S32, when the temperature of the drain 22 is higher than the set temperature (step S32: No), the control device 34 shifts the process to step S34. In step S34, the control device 34 closes the second drain discharge valve V23 and stops discharging the drain 22 from the flash tank 23 through the second drain discharge line L23. Further, the control device 34 opens the first drain discharge valve V22, discharges the drain 22 from the flash tank 23 through the first drain discharge line L22, and supplies it to the water supply tank 14.

  Thus, the control device 34 controls the opening and closing of the second drain discharge valve V23 while adjusting the opening of the first drain discharge valve V22 according to the temperature of the drain 22. In general, when the operation of the first load device 13 is initial, such as when the first load device 13 is activated, the drain 22 discharged from the first load device 13 is at a low temperature. A large amount of low-temperature drain 22 is discharged. Therefore, a large amount of low-temperature drain 22 is discharged from the flash tank 23. When the low-temperature drain 22 discharged from the flash tank 23 is collected in the water supply tank 14, there is a possibility that the temperature of the drain 22 stored in the water supply tank 14 is lowered. Further, the drain 22 discharged in the initial operation of the first load device 13 often includes a large amount of impurities such as sludge and rust or air. Therefore, if the drain 22 collected in the flash tank 23 is supplied to the water supply tank 14, it becomes difficult to use it in the boiler 11.

  In the steam recovery system 16, when the temperature of the drain 22 is lower than the set temperature, the control device 34 controls the first drain discharge valve V <b> 22 and the second drain discharge valve V <b> 23, and the drain 22 of the flash tank 23. Is discharged from the flash tank 23 through the second drain discharge line L23 without passing through the first drain discharge line L22. As a result, the steam recovery system 16 can suppress the supply of the drain 22 containing a large amount of impurities or air to the water supply tank 14 at a low temperature. Thereby, the steam recovery system 16 can stably supply the available drain 22 to the water supply tank 14. As a result, the steam recovery system 16 can stably use the drain 22 supplied to the water supply tank 14.

  Furthermore, when the steam system 10 includes a plurality of first load devices 13, if the steam recovery system 16 is provided for each drain supply line L14 connected to the first load device 13, for each drain supply line L14. It can correspond to.

  The steam recovery system 16 includes an output unit 47. The output unit 47 outputs operation information based on the detection result calculated by the control device 34, thereby notifying whether or not there is an abnormality in the operation state of the steam recovery system 16 by, for example, lighting of a lamp or an alarm. As a result, the steam recovery system 16 can notify a worker or the like that an abnormality may have occurred in the operation state of the steam recovery system 16, so that the worker or the like can easily detect an abnormality in the steam recovery system 16. Can be recognized.

  As described above, in the steam recovery system 16, the control device 34 is based on the detection results of the pressure sensor 31, the water level detector 32, and the temperature sensor 33, and the steam control valve V21, the first drain discharge valve V22, and the second drain discharge. The valve V23 is controlled. Thereby, the steam recovery system 16 can stably recover the flash steam 28 having a high dryness in the flash tank 23 and can stably supply the drain 22 that can be used to the water supply tank 14. As a result, a highly reliable steam system 10 can be provided.

  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 this embodiment, the water level detector 32 employs a float method, but is not limited to this, and employs a known water level detection method such as an electrode rod method using an electrode rod, a water pressure detection method, or the like. You may use the apparatus which was made.

  Moreover, in this embodiment, although the 2nd drain discharge line L23 is branched and provided from the 1st drain discharge line L22, it is not limited to this, The 1st drain discharge line L22 is the 2nd drain. The first drain discharge line L22 and the second drain discharge line L23 may be connected to the flash tank 23, respectively, by branching from the discharge line L23.

  Further, in the present embodiment, the drain 22 discharged from the flash tank 23 or the drain 22 passing through the bypass line L15 is supplied to the water supply tank 14 so that the drain 22 is stored only by the water supply tank 14. It is not limited to this. For example, the first drain discharge line L22 is on the upstream side of the water supply tank 14, and specifically, a drain tank is provided separately from the water supply tank 14 between the connection point with the bypass line L15 and the water supply tank 14. The drain 22 may be stored in the drain tank.

10 Steam system 11 Boiler (steam supply source)
12 Steam header 13 First load device 14 Water supply tank 15 Second load device 16 Steam recovery system 21 Steam 22 Drain 23 Flash tank (separation part)
24 Steam trap 25 Water 26 Make-up water 27 Depressurized steam 28 Flash steam 31 Pressure sensor (pressure detector)
32 Water level detector (water level detector)
33 Temperature sensor (temperature measurement unit)
34 Control device (control unit)
41 Water level detection cylinder 42 Float 43 Water level sensor 45, 46 Connecting pipe 47 Output section L11 First steam supply line L12 Second steam supply line L13 Third steam supply line L14 Drain supply line L15 Bypass line L21 Steam exhaust line L22 First drain Discharge line L23 Second drain discharge line L24 Internal pressure adjustment line V11 Emergency discharge valve V12, V25 Pressure reducing valve V21 Steam control valve (steam control unit)
V22 1st drain discharge valve (1st drain adjustment part)
V23 Second drain discharge valve (second drain adjustment unit)
V24 Safety valve V26, V27 Check valve V28 Internal pressure control valve

Claims (3)

A separation unit that collects drain discharged from the load device and separates flash vapor generated from the collected drain;
A pressure detection unit provided in the separation unit for detecting the pressure in the separation unit;
A steam discharge line connected to the separation unit and discharging the flash vapor from the separation unit;
A steam control valve which is provided in the steam discharge line and adjusts the discharge amount of the flash steam flowing through the steam discharge line;
A control unit that controls the steam control valve based on a detection result of the pressure detection unit;
Have
The control unit compares a detection pressure of the pressure detection unit with a set pressure, and when the pressure detection unit is equal to or higher than the set pressure, the steam control valve is opened in accordance with the detection pressure. The discharge amount of the flash steam is adjusted by adjusting the opening of the steam control valve, and when the detected pressure is lower than a set pressure , the discharge of the flash steam is stopped by closing the steam control valve. A steam recovery system. In claim 1,
A water level detection unit that is provided in the separation unit and detects a water level of the drain in the separation unit;
A first drain discharge line connected to the separator and discharging the drain from the separator;
A first drain adjustment unit that is provided in the first drain discharge line and adjusts an amount of drain discharged through the first drain discharge line;
Have
The said control part controls the said 1st drain adjustment part based on the detection result of the said water level detection part, and adjusts the discharge | emission amount of the said drain, The steam recovery system characterized by the above-mentioned. In claim 2,
A temperature measurement unit that is provided in the separation unit and measures the temperature of the drain in the separation unit;
A second drain discharge line connected to the separator and discharging the drain from the separator;
A second drain adjusting portion that is provided in the second drain discharge line and discharges the drain flowing through the second drain discharge line;
The control unit controls the second drain adjusting unit to discharge the drain through the second drain discharge line when the temperature of the drain is lower than a set temperature. system.

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