JP2014178052A - Drain recovery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce frequency of opening/closing a valve and frequency of adjusting a valve opening and thus further elongate the service life of the valve.SOLUTION: A drain recovery system includes: a flash tank 23 for recovering drain 22 discharged from a load device 13 that uses steam 21 supplied from a boiler 11; a drain discharge line L22 for guiding the drain 22 to outside of the flash tank 23; a drain discharge valve V22 that is installed in the drain discharge line L22 to adjust a flow rate of the drain 22 flowing in the drain discharge line L22 in accordance with an opening of the valve; and a control device 37 that stores the opening of the drain discharge valve V22 during steady operation of the load device 13 and controls the drain discharge valve V22 to adjust the opening of the drain discharge valve V22 to the stored opening when discharge of the drain 22 to outside of the flash tank 23 is started.

Description

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

  A drain recovery system that recovers drain discharged from a load device includes a water level sensor that detects the water level of the drain. The drain recovery system controls the opening and closing of a valve that discharges the recovered drain in accordance with the water level of the drain detected by the water level sensor, and discharges the drain. When the drain water level reaches the upper limit water level, the drain recovery system opens the valve and discharges the drain. When the drain water level drops to the lower limit water level, the drain recovery system closes the valve and stops draining. By repeatedly performing this valve opening / closing operation, the life of the valve is shortened. Therefore, it is desirable to drain the drain as continuously as possible to reduce the frequency of opening and closing the valve.

  In view of this, there has been proposed an apparatus that controls the drain discharge amount to keep the frequency of opening and closing the control valve low (see, for example, Patent Document 1).

  In Patent Document 1, a capacitance-type water level sensor is used to continuously detect a change in the water level of the condensate in the condensate tank (corresponding to the above-mentioned drain). The opening and closing frequency of the control valve is kept low by controlling the opening of the condensate tank and controlling the amount of condensate discharged from the condensate tank while the control valve is open.

Japanese Unexamined Patent Publication No. 7-317993

  However, when the load device is activated, the operation state of the load device is not stable, and the drain water level greatly fluctuates. In addition, when the load equipment is repeatedly stopped and operated, the water level of the drain greatly fluctuates. In such a case, in the control of opening the control valve so that the drain water level is within the reference range as in Patent Document 1, it is possible to reduce the opening and closing frequency of the valve, but the frequency of adjusting the opening degree of the valve It is not sufficient as an effect of reducing the above.

  The present invention solves the above-described problem, and a drain recovery system that can further increase the life of the valve by reducing the frequency of opening and closing the valve and also reducing the frequency of adjusting the opening of the valve. The purpose is to provide.

  In order to achieve the above object, a drain recovery system according to the present invention includes a drain recovery tank that recovers drain discharged from a load device that uses steam supplied from a steam supply source, and the drain recovery tank. A drain discharge line that leads to the outside, a drain adjustment unit that is provided in the drain discharge line and adjusts the flow rate of the drain that flows through the drain discharge line, according to the opening of the valve, and the valve during steady operation of the load device. A control unit that stores the opening and controls the drain adjustment unit to adjust the opening of the valve to the opening when the drain starts to be discharged out of the drain recovery tank. Features.

  According to this drain recovery system, the opening degree of the drain adjustment unit during the steady operation of the load device is stored in advance, and when the drain discharge is started outside the drain recovery tank, the opening degree of the valve of the drain adjustment unit is set. By adjusting to the memorized opening, it is possible to reduce the frequency of opening and closing the valve of the drain control unit and the frequency of adjusting the opening of the valve until the load device reaches steady operation, further extending the life of the valve Can be achieved. In addition, when the opening degree of the valve of the drain control unit is adjusted in accordance with the water level of the drain in the drain recovery tank before the load equipment reaches steady operation, the valve of the drain control unit is hunted due to sudden load fluctuations. However, according to the drain recovery system of the present invention, when starting the discharge of drain outside the drain recovery tank, by adjusting the opening of the valve of the drain adjustment unit to the stored opening, Such a situation can be prevented. In addition, the hunting said here means the phenomenon which repeats the overshoot with an opening degree too large, and the undershoot with an opening degree too small with respect to the appropriate opening degree of the valve corresponding to a certain water level.

  Further, in the drain recovery system of the present invention, the drain recovery system includes a water level detection unit that is provided in the drain recovery tank and detects the water level of the drain in the drain recovery tank, and the control unit is configured to operate the load device during steady operation. When the drain opening of the drain recovery tank is started, the drain adjustment unit is controlled to adjust the opening of the valve to the stored opening, and then the water level is stored. When the drain adjustment unit is controlled based on the water level in the drain recovery tank detected by the detection unit to increase the valve opening when the drain water level rises, and the drain water level falls Further, the opening degree of the valve is reduced.

  After the load device is in a steady operation, there is little change in the operation state of the load device, so there is little increase or decrease in the drain discharge amount, and the fluctuation range of the drain water level in the drain recovery tank is small. Therefore, according to the drain recovery system of the present invention, it is only necessary to finely adjust the opening degree of the valve of the drain adjustment unit stored and controlled in advance, and while reducing the frequency of the opening degree adjustment of the valve of the drain adjustment unit, The water level of the drain accumulated in the recovery tank can be kept within a predetermined range.

  In the drain recovery system of the present invention, the control unit updates and stores the opening degree of the valve of the drain adjustment unit during the steady operation of the load device when the load device is stopped. And

  According to this drain recovery system, the valve opening of the drain control unit during the steady operation of the load device is stored when the operation is stopped, and is used during the next operation of the load device. The valve opening of the drain control unit can be set according to the amount of drain discharged, thus reducing the frequency of opening and closing the valve of the drain control unit and the frequency of adjusting the valve opening. It is possible to obtain a remarkable effect.

  Further, in the drain recovery system of the present invention, a plurality of the load devices are provided, the drain recovery tank is supplied with drain discharged from each of the load devices, and the control unit is configured to supply a single or a plurality of each of the load devices. For each combination of operation, the opening degree of the valve of the drain adjustment unit at the time of steady operation is stored, and when discharging of the drain to the outside of the drain recovery tank is started, the drain adjustment unit is controlled to open the valve. The degree of adjustment is adjusted to the memorized opening.

  According to this drain recovery system, the opening degree of the valve of the drain control unit at the time of steady operation is stored in advance for each combination of operation of single or plural load devices, and the drain is discharged outside the drain recovery tank. When starting, the valve opening of the drain control unit is adjusted to the memorized opening, so that the frequency of opening and closing the valve of the drain control unit and the valve opening control until a plurality of load devices reach steady operation. , And the life of the valve can be further extended.

  According to the present invention, it is possible to reduce the frequency of opening and closing the valve and also reduce the frequency of adjusting the opening of the valve, thereby further extending the life of the valve.

It is a schematic block diagram which shows the steam system with which the drain collection system which concerns on Embodiment 1 of this invention is applied. It is a flowchart which shows control of the drain discharge valve by the control apparatus in the drain collection | recovery system which concerns on Embodiment 1 of this invention. It is a schematic block diagram which shows the steam system with which the drain recovery system which concerns on Embodiment 2 of this invention is applied. It is a flowchart which shows control of the drain discharge valve by the control apparatus in the drain collection | recovery system which concerns on Embodiment 2 of this invention.

  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.

[Embodiment 1]
An example of the steam system 10 to which the drain recovery system 16 according to the present embodiment is applied will be described. FIG. 1 is a schematic configuration diagram illustrating a steam system 10 to which a drain recovery system 16 according to the present embodiment is applied.

  As shown in FIG. 1, the steam system 10 includes a boiler (steam supply source) 11, a steam header 12, a load device 13, a water supply tank 14, a flash steam utilization load device 15, and a drain recovery system 16. I have.

  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 a combustion type, as the fuel, for example, gaseous fuel such as city gas, propane gas, and biogas, and liquid fuel such as heavy oil and kerosene are used. 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 through a first steam supply line L11. The first steam supply line L11 is a line connecting 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 the present embodiment, one boiler 11 is provided, but steam supplied from a plurality of boilers (not shown) may be collected in the steam header 12.

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

  The second steam supply line L12 is provided with a steam flow rate control valve (steam flow rate control unit) 41. The steam flow rate adjusting valve 41 is for adjusting the flow rate of the steam 21 passing through the second steam supply line L12. The second steam supply line L <b> 12 is provided with a steam pressure sensor (steam pressure detection unit) 42 between the steam flow rate adjustment valve 41 and the load device 13. The steam pressure sensor 42 detects the pressure in the second steam supply line L12 that reaches the load device 13 via the steam flow rate adjustment valve 41. Here, the steam flow rate adjustment valve 41 is based on an electrical signal (pressure detection signal) input from the steam pressure sensor 42, and the flow rate of the steam 21 sent to the load device 13 is a flow rate suitable for the operation of the load device 13. It is controlled autonomously or by a controller (not shown). The second steam supply line L <b> 12 is provided with a steam flow sensor (steam flow rate detection unit) 43 between the steam header 12 and the steam flow rate control valve 41. The steam flow sensor 43 detects the flow rate of the steam 21 adjusted by the steam flow control valve 41.

  The load device 13 uses the steam 21 fed from the steam header 12 through the second steam supply line L12 as a heating source or a power source. In the present embodiment, the load device 13 uses the steam 21 as a heating source. When the steam 21 passes through a steam supply passage (not shown) in the load device 13, the steam 21 loses latent heat and partially condenses to become high-pressure and high-temperature drain (condensed water) 22. The 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 load device 13 is connected to the flash tank 23 in the drain recovery system 16 through a drain supply line L14. Details of the flash tank 23 will be described later. As described above, the load device 13 uses the supplied steam 21 as a heating source, and generates the drain 22 when the steam 21 is used. The drain 22 is discharged through the drain supply line L14 and supplied to the flash tank 23. 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 load device 13 to pass through. Therefore, only the drain 22 discharged from the load device 13 through the drain supply line L14 and passing through the steam trap 24 is supplied to the flash tank 23.

  Further, the drain supply line L14 is connected to a bypass line L15 at a position 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 middle of the drain discharge line L22. The drain discharge line L22 is connected to the water supply tank 14 as will be described in detail later. That is, the bypass line L15 supplies the drain 22 flowing through the drain supply line L14 to the water supply tank 14. The bypass line L15 is provided with a bypass discharge valve V11 in the middle of the bypass line L15. The bypass discharge valve V11 discharges the drain 22 in the bypass line L15. The bypass discharge valve V11 is opened when the later-described drain discharge valve V22 fails, such as when the water level in the flash tank 23 becomes higher than the normal set range due to clogging in the drain discharge line L22, etc. As a result, the drain 22 is supplied to the water supply tank 14 through the bypass line L15 without passing through the flash tank 23.

  In the bypass line L15, a bypass drain drain line L16 is connected between the drain supply line L14 and the bypass discharge valve V11. The bypass drain drain line L16 is a line that connects the bypass line L15 and the downstream side of the blow discharge valve V23 in the blow discharge line L23 described later. The bypass drain drain line L16 supplies the drain 22 flowing through the drain supply line L14 to the blow discharge line L23. The bypass drain discharge line L16 is provided with a bypass drain drain valve V13 that opens and closes the bypass drain discharge line L16 in the middle of the bypass drain discharge line L16.

  The water supply tank 14 is for storing the drain 22. It is connected to the boiler 11 by a water supply line L17. The drain 22 in the water supply tank 14 is supplied to the boiler 11 through the water supply line L17 as water 25 for generating the steam 21. The water supply tank 14 is supplied with makeup water 26. When the water supplied to the boiler 11 is insufficient with only the drain 22 supplied to the water supply tank 14, the makeup water 26 is supplied to the water supply tank 14 and supplied to the boiler 11 as water 25.

  By the way, the steam header 12 mentioned above is connected in the middle of the flash steam discharge line L21 by the 3rd steam supply line L13. The third steam supply line L13 is a line connecting the steam header 12 and the flash steam discharge line L21. The flash steam discharge line L21, which will be described in detail later, connects the flash tank 23 and the flash steam utilization load device 15 in the drain recovery system 16. For this reason, a part of the steam 21 collected in the steam header 12 is sent from the steam header 12 to the flash steam discharge line L21 through the third steam supply line L13, and the flash steam is used through the flash steam discharge line L21. Air is sent to the load device 15.

  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 is supplied to the flash steam using load device 15 through the flash steam discharge line L21 as a decompressed steam 27 by the pressure reducing valve V12.

  The flash steam use load device 15 is a heating source or a power source, and the like, a flash steam 28 to be described later discharged from the flash tank 23 through the flash steam discharge line L21, one of the third steam supply line L13 and the flash steam discharge line L21. The reduced pressure steam 27 that has passed through the pressure reducing valve V12 from the steam header 12 is used. The flash steam load device 15 includes one or more low pressure steam load devices. In the present embodiment, the flash steam utilization load device 15 uses the flash steam 28 in preference to the decompressed steam 27 as a heating source. The flash steam using load device 15 uses the decompressed steam 27 as a shortage when the flash steam 28 alone is insufficient in the amount of steam used in the flash steam using load device 15.

  As shown in FIG. 1, the drain recovery system 16 includes a flash tank (drain recovery tank) 23, a flash steam discharge line L21, a flash steam control valve V21, a drain discharge line L22, and a drain discharge valve (drain control unit). ) V22, a drain drain line comprising a bypass line L15, a bypass drain discharge line L16 and a blow drain line L23, a bypass drain drain valve (drain drain valve) V13, a water level detector (water level detector) 34, and a temperature sensor (Temperature detection part) 35, the flash tank pressure sensor 36, and the control apparatus (control part) 37 are provided.

  The flash tank 23 collects the drain 22 discharged from the load device 13 through the drain supply line L14. In the flash tank 23, 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.

  One end of the flash steam discharge line L <b> 21 is connected to the flash tank 23, and the other end is connected to the flash steam utilization load device 15. The flash steam discharge line L21 is a line for discharging the flash steam 28 from the flash tank 23. The flash steam discharge line L21 is provided with a pressure reducing valve V25 in the middle of the flash steam discharge line L21 and upstream of the position where the third steam supply line L13 is connected to the flash steam discharge line L21. The flash steam 28 passes through the flash steam discharge line L21 from the flash tank 23 and is depressurized by the pressure reducing valve V25, and then is sent to the flash steam using load device 15.

  In the flash vapor discharge line L21, a check valve V26 is provided between the flash tank 23 and the pressure reducing valve V25. The check valve V26 prevents the reduced pressure steam 27 supplied through the third steam supply line L13 from flowing to the flash tank 23 side.

  The flash steam control valve V21 is provided in the flash steam discharge line L21. The flash steam control valve V21 is provided between the flash tank 23 and the check valve V26, and adjusts the flow rate of the flash steam 28 passing through the flash steam discharge line L21. When the flash steam control valve V21 is closed and the flash steam 28 is not sent to the flash steam utilization load device 15, the pressure is reduced from the steam header 12 through a part of the third steam supply line L13 and the flash steam discharge line L21. Only the reduced-pressure steam 27 that has passed through the valve V12 is used as a heating source or a power source for the flash steam utilization load device 15.

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

  The drain discharge line L22 has one end connected to the flash tank 23 and the other end connected to the water supply tank 14. The 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 drain discharge line L22.

  The drain discharge valve V22 is provided in the drain discharge line L22. The drain discharge valve V22 adjusts the flow rate of the drain 22 flowing through the drain discharge line L22 according to the opening degree of the valve.

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

  The blow discharge line L23 is provided in the middle of the drain discharge line L22, specifically, between the flash tank 23 and the drain discharge valve V22. The blow discharge line L23 is a line for discharging the drain 22 from the flash tank 23 to the outside. The blow discharge line L23 is provided with a blow discharge valve V23. The blow discharge valve V23 discharges the drain 22 flowing through the blow discharge line L23. As described above, the blow drain line L23 is connected to the bypass drain discharge line L16 on the downstream side of the blow discharge valve V23 in the flow direction of the drain 22. One end of the bypass drain discharge line L16 is connected between the drain supply line L14 and the bypass discharge valve V11 in the bypass line L15, and the other end is connected to the blow discharge line L23. That is, a part of the bypass line L15, a part of the bypass drain discharge line L16, and a part of the blow discharge line L23 constitute a drain drain line that drains the drain 22 flowing through the drain supply line L14 without passing through the flash tank 23. ing.

  As described above, the bypass drain drain valve V13 is provided in the bypass drain discharge line L16. By opening the drain drain valve V13, the drain 22 is discharged through the drain drain line including a part of the bypass line L15, the bypass drain discharge line L16, and a part of the blow discharge line L23. On the other hand, the bypass drain drain valve V13 is closed to stop discharging the drain 22 from the drain drain line.

  The water level detector 34 is provided outside the flash tank 23. The water level detector 34 detects the water level of the drain 22 in the flash tank 23. The water level detector 34 includes a water level detection cylinder 34A, a float 34B, and a water level sensor (water level detection unit) 34C. The water level detection cylinder 34 </ b> A is provided up and down along the outer side surface of the flash tank 23. The lower side of the water level detection cylinder 34A communicates with the inside of the bottom of the flash tank 23 through a communication pipe 34D. The water level detection cylinder 34A is communicated at its upper side with the upper side inside of the flash tank 23 through a communication pipe 34E.

  The water level sensor 34C detects the height of the float 34B provided in the water level detection cylinder 34A and detects the water level of the drain 22 in the water level detection cylinder 34A. In the water level detection cylinder 34A, the drain 22 flows from the flash tank 23 through the communication pipe 34D 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 34A become substantially equal. For this reason, the water level sensor 34C detects the water level of the drain 22 in the water level detection cylinder 34A by detecting the height of the float 34B in the water level detection cylinder 34A.

  The temperature sensor 35 is provided between the steam trap 24 and the flash tank 23 in the drain supply line L14. The temperature sensor 35 detects the temperature of the drain 22 passing through the drain supply line L14.

  The flash tank pressure sensor 36 is provided in the flash tank 23. The flash tank pressure sensor 36 detects the pressure in the flash tank 23.

  The control device 37 controls the drain collection system 16. The control device 37 is a computer including a CPU and a memory, for example. In this embodiment, the control device 37 outputs a control signal for controlling the opening degree of the drain discharge valve V22. Further, the control device 37 outputs a control signal for controlling the opening / closing of the bypass drain drain valve V13. Further, the control device 37 outputs a control signal for controlling the opening / closing of the bypass discharge valve V11. Further, the control device 37 is electrically connected to a water level sensor 34C, a temperature sensor 35, a steam pressure sensor 42, a steam flow rate sensor 43, and a flash tank pressure sensor 36 of the water level detector 34, and each sensor 34C, 35, 42, The drain recovery system 16 is controlled based on the electrical signals input from 43 and 36.

  When the control device 37 outputs a control signal to the drain discharge valve V22, the control device 37 stores the control signal in a memory. Specifically, the control device 37 stores the control signal output to the drain discharge valve V22 during the steady operation of the load device 13. The steady operation of the load device 13 is a state in which the load device 13 is stably operated continuously, and the steam 21 with a constant flow rate is supplied to the load device 13 with the steam flow rate control valve 41 at a constant opening. Thus, the drain 22 having a constant flow rate is discharged from the load device 13. The control device 37 updates and stores the control signal output to the drain discharge valve V22 when the operation of the load device 13 is stopped.

  In addition, the control device 37 stores information on the set water level of the drain 22 in the flash tank 23 in advance in the memory. The set water level of the drain 22 is a range of the water level of the drain 22 necessary for suitably generating the flash steam 28 for operating the flash steam utilization load device 15. Whether or not the water level of the drain 22 is the set water level is acquired from an electrical signal (water level signal) input from the water level sensor 34C.

  In the control device 37, information on the set temperature of the drain 22 is stored in advance in the memory. The set temperature of the temperature of the drain 22 is for discharging the drain 22 in the initial operation of the load device 13. Whether or not the temperature of the drain 22 is a set temperature is acquired from an electric signal (temperature detection signal) input from the temperature sensor 35.

  In addition, the control device 37 can acquire the operating state of the load device 13 with reference to the electrical signal input from the steam flow rate control valve 41 and the electrical signal (pressure detection signal) input from the steam pressure sensor 42. it can. As described above, the steam flow rate adjusting valve 41 is suitable for the operation of the load device 13 based on the electric signal (pressure detection signal) input from the steam pressure sensor 42 so that the flow rate of the steam 21 sent to the load device 13 is suitable. The flow rate is controlled autonomously or by a controller (not shown) so that the flow rate becomes high. That is, the control device 37 acquires whether the operation state of the load device 13 is a steady operation by referring to the electric signal input from the steam flow rate adjustment valve 41 or the electric signal input from the steam pressure sensor 42. And a change in the operating state of the load device 13 can be acquired.

  Further, the control device 37 can acquire the operating state of the load device 13 from the flow rate of the steam 21 flowing through the second steam supply line L12 based on the electrical signal (flow rate detection signal) input from the steam flow rate sensor 43. . That is, the control device 37 can acquire whether the operation state of the load device 13 is a steady operation based on the electric signal input from the steam flow sensor 43 and also acquire a change in the operation state of the load device 13. can do. The change in the operating state of the load device 13 is one of an electrical signal input from the steam flow rate control valve 41, an electrical signal input from the steam pressure sensor 42, or an electrical signal input from the steam flow rate sensor 43. You can get more.

  FIG. 2 is a flowchart showing control of the drain discharge valve V22 by the control device 37. FIG. 2 shows a procedure for stopping the load device 13 described above from starting. In the present embodiment, when the load device 13 is started, the steam 21 is generated by the boiler 11 and the steam 21 necessary for operating the load device 13 is in a state where the steam header 12 is stored. To do. In addition, before the load device 13 is started, the steam flow rate adjustment valve 41 provided in the second steam supply line L12 is in a closed state. Further, before the load device 13 is started, the bypass drain drain valve V13 of the bypass drain discharge line L16 is in a closed state. Further, the bypass discharge valve V11 of the bypass line L15 is in a closed state. Further, the blow discharge valve V23 of the blow discharge line L23 is in a closed state. Further, before the load device 13 is started, the control device 37 stores in advance a control signal output to the drain discharge valve V22 during the last steady operation of the load device 13.

  When starting the load device 13, the steam 21 is supplied to the load device 13 through the second steam supply line L <b> 12 by opening the steam flow rate adjustment valve 41. Then, the drain 22 generated in the load device 13 is supplied to the flash tank 23 through the drain supply line L14. At this time, the control device 37 acquires the electrical signal (temperature detection signal) input from the temperature sensor 35, and if the temperature of the drain 22 is equal to or higher than the set temperature (step S1: Yes), the bypass drain drain valve V13 is set. If the drain 22 is kept closed (step S2) and the temperature of the drain 22 is lower than the set temperature (step S1: No), the bypass drain drain valve V13 is opened (step S3). Note that when the bypass drain drain valve V13 is opened in step S3, the control device 37 keeps the bypass drain drain valve V13 open until the temperature of the drain 22 becomes equal to or higher than the set temperature. In step S3, by opening the bypass drain drain valve V13, the drain 22 is drained without passing through the flash tank 23 through the drain drain line including the bypass drain discharge line L16. The drain 22 discharged when the operation of the load device 13 is in an initial stage is low in temperature and often contains a large amount of impurities such as sludge and rust, and air. Therefore, even if the drain 22 discharged in the initial stage of the operation of the load device 13 is recovered by the flash tank 23 and supplied to the water supply tank 14, it is difficult to use it in the boiler 11. Therefore, when starting the load device 13, the drain 22 having such a low temperature is drained without passing through the flash tank 23.

  Next, when the water level of the drain 22 becomes the set water level by obtaining the electrical signal (water level signal) input from the water level sensor 34C after the bypass drain drain valve V13 is closed in step S2 (step S4: Yes). The control device 37 adjusts the drain discharge valve V22 to a previously stored opening (step S5). By closing the bypass drain drain valve V13, drainage of the drain 22 through the drain drain line including the bypass drain discharge line L16 is stopped, and the drain 22 is supplied and stored in the flash tank 23. When the water level of the drain 22 reaches the set water level, the water level of the drain 22 accumulated in the flash tank 23 is kept constant within the range of the set water level by adjusting the drain discharge valve V22 to a previously stored opening. It will be. Further, until the water level of the drain 22 reaches the set water level (step S4: No), the control device 37 maintains the drain discharge valve V22 in a closed state.

  In step S5, after adjusting the drain discharge valve V22 to the previously stored opening, if the operation of the load device 13 is not stopped (No in step S6), the operation of the load device 13 is continued, so the control device In step 37, the opening degree of the drain discharge valve V22 adjusted in step S5 is maintained and this control is continued. Whether or not the operation of the load device 13 is stopped is input from the electric signal input from the steam flow control valve 41 (when closed), the electric signal input from the steam pressure sensor 42, or the steam flow sensor 43. Any one of the electrical signals can be acquired.

  In step S6, the operation of the load device 13 is not stopped (step S6: No), and the operation state of the load device 13 may change while the operation of the load device 13 is continued. In this case, the water level of the drain 22 in the flash tank 23 changes. Specifically, when the water level of the drain 22 acquired by the electrical signal (water level signal) input from the water level sensor 34C is constant within the set water level range (step S7: Yes), the control device 37 adjusts in step S5. The opening degree of the drain discharge valve V22 thus maintained is maintained (step S8). On the other hand, if the water level of the drain 22 is not constant (step S7: No) and rises (step S9: Yes), the control device 37 greatly adjusts the opening of the drain discharge valve V22 (step S10). Thereby, the discharge amount of the drain 22 flowing into the water supply tank 14 through the drain discharge line L22 increases, and the water level of the drain 22 accumulated in the flash tank 23 is kept constant. Further, when the water level of the drain 22 is not increased (step S9: No) but is decreased (step S11: Yes), the control device 37 adjusts the opening of the drain discharge valve V22 to be small (step S12). Thereby, the discharge amount of the drain 22 flowing into the water supply tank 14 through the drain discharge line L22 is reduced, and the water level of the drain 22 accumulated in the flash tank 23 is kept constant. In addition, after adjusting the opening degree of the drain discharge valve V22 in step S10 or step S12, it may reach step S8 and maintain the opening degree of the drain discharge valve V22. However, as shown in FIG. 2, the process returns to step S6. If the operation of the load device 13 is not stopped (step S6: No), it is preferable to check the water level of the drain 22 in step S7.

  After the opening degree of the drain discharge valve V22 is maintained in step S7, if the load device 13 is in a steady operation (step S13: Yes), the control device 37 stores the opening degree of the drain discharge valve V22 during the steady operation. And update (step S14). When there are a plurality of openings of the drain discharge valve V22 stored in step S14, all the openings are stored. After step S14, the process returns to step S6, and if the operation of the load device 13 is not stopped (step S6: No), the water level of the drain 22 is confirmed in step S7. On the other hand, if the load device 13 is not in steady operation in step S13 (step S13: No), the control device 37 returns to step S6, and if the operation of the load device 13 is not stopped (step S6: No). In step S7, the water level of the drain 22 is confirmed.

  In step S <b> 13, the determination of the steady operation of the load device 13 is acquired based on an electric signal (flow rate detection signal) input from the steam flow rate sensor 43. Alternatively, the determination of the steady operation of the load device 13 can be obtained by referring to an electrical signal input from the steam flow rate control valve 41 or an electrical signal input from the steam pressure sensor 42. Alternatively, the determination of the steady operation of the load device 13 may be acquired based on an electric signal input from a controller (not shown) that controls the load device 13. Alternatively, the determination of the steady operation of the load device 13 can be obtained based on the control signal of the control device 37 itself maintaining the drain discharge valve V22 at a predetermined opening for a predetermined time based on the control signal for controlling the drain discharge valve V22. .

  Note that when the drain 22 accumulates in the flash tank 23, flash vapor 28 is generated from the drain 22. Therefore, the control device 37 opens the flash steam control valve V21 and feeds the flash steam 28 to the flash steam utilization load device 15 through the flash steam discharge line L21. Thereby, the flash steam 28 is used as a heating source or a power source of the flash steam utilization load device 15. At this time, the control device 37 adjusts the opening degree of the flash steam control valve V21 based on the electric signal (flash steam pressure detection signal) input from the flash tank pressure sensor 36.

  By the way, when the operation of the load device 13 is stopped in step S6 (step S6: Yes), and the opening degree of the drain discharge valve V22 stored in step S14 is the opening degree of the drain discharge valve V22 used in step S5. When there is a change (step S15: Yes), the control device 37 outputs to the drain discharge valve V22 when the opening degree is maintained most continuously from when the load device 13 is started to when it is stopped. The control signal, that is, the opening degree of the drain discharge valve V22 during the steady operation that was most stable is stored and updated (step S16), and this control is terminated. The control signal (opening degree of the drain discharge valve V22) to the drain discharge valve V22 stored and updated is applied to the next operation of the load device 13. On the other hand, when there is no change in the stored opening degree of the drain discharge valve V22 (step S15: No), the control device 37 does not update it while storing the opening degree of the drain discharge valve V22 used in step S5. End control.

  Thus, the drain recovery system 16 according to the present embodiment is a flash tank (drain recovery tank) that recovers the drain 22 discharged from the load device 13 that uses the steam 21 supplied from the boiler (steam supply source) 11. 23, a drain discharge line L22 for guiding the drain 22 to the outside of the flash tank 23, and a drain discharge valve (drain adjustment) which is provided in the drain discharge line L22 and adjusts the flow rate of the drain 22 flowing through the drain discharge line L22 according to the opening of the valve. Part) V22 and the opening degree of the drain discharge valve V22 during the steady operation of the load device 13 are stored, and when the discharge of the drain 22 is started outside the flash tank 23, the drain discharge valve V22 is controlled to control the drain discharge valve V22. And a control device (control unit) 37 for adjusting the opening degree to the stored opening degree.

  According to this drain recovery system 16, the opening degree of the drain discharge valve V <b> 22 during steady operation of the load device 13 is stored in advance, and when the drain 22 starts to be discharged out of the flash tank 23, Since the opening degree is adjusted to the memorized opening degree, the opening / closing frequency of the drain discharge valve V22 and the opening degree adjustment frequency of the drain discharge valve V22 can be reduced until the load device 13 reaches the steady operation. Further life extension of the valve can be achieved. Moreover, when the opening degree of the drain discharge valve V22 is adjusted in accordance with the water level of the drain 22 in the flash tank 23 until the load device 13 reaches the steady operation, the drain discharge valve V22 is hunted due to a sudden load fluctuation. However, according to the drain recovery system 16 of this embodiment, when the discharge of the drain 22 is started outside the flash tank 23, the opening of the drain discharge valve V22 is adjusted to the stored opening. Therefore, such a situation can be prevented.

  Further, the drain recovery system 16 according to the present embodiment includes a water level detector (water level detection unit) 34 that is provided in the flash tank 23 and detects the water level of the drain 22 in the flash tank 23. When opening the drain discharge valve V22 during steady operation of the load device 13 and starting discharging the drain 22 outside the flash tank 23, the drain discharge valve V22 is controlled to store the opening of the drain discharge valve V22. Then, the drain discharge valve V22 is controlled based on the water level in the flash tank 23 detected by the water level detector 34. When the water level of the drain 22 rises, the opening of the drain discharge valve V22 is adjusted. When the water level of the drain 22 falls, the opening degree of the drain discharge valve V22 is reduced.

  After the load device 13 is in a steady operation, the change in the operation state of the load device 13 is small, so the amount of discharge of the drain 22 is small and the fluctuation range of the water level of the drain 22 in the flash tank 23 is small. Therefore, according to the drain recovery system 16, it is only necessary to finely adjust the opening degree of the drain discharge valve V22 stored and controlled in advance, and the frequency of adjusting the opening degree of the drain discharge valve V22 is reduced, and the flush tank 23 is adjusted. The water level of the accumulated drain 22 can be kept within a predetermined range.

  Further, in the drain recovery system 16 according to the present embodiment, the control device 37 updates and stores the opening degree of the drain discharge valve V22 during the steady operation of the load device 13 when the operation of the load device 13 is stopped.

  According to this drain recovery system 16, since the opening degree of the drain discharge valve V <b> 22 during the steady operation of the load device 13 is stored when the operation is stopped and used during the next operation of the load device 13, Since the opening degree of the drain discharge valve V22 can be set according to the discharge amount of the drain 22 discharged according to the state, the water level error is small, the frequency of opening and closing the drain discharge valve V22 and the frequency of adjusting the opening degree of the drain discharge valve V22. It is possible to obtain a remarkable effect of further reducing the valve length and further extending the life of the valve.

[Embodiment 2]
An example of the steam system 10 to which the drain recovery system 16 according to the present embodiment is applied will be described. FIG. 3 is a schematic configuration diagram showing the steam system 10 to which the drain recovery system 16 according to the present embodiment is applied. The steam system 10 according to the present embodiment is different from the steam system 10 according to the first embodiment described above in that a plurality of load devices 13 are provided. Therefore, in the following description, the same code | symbol is attached | subjected to the part equivalent to Embodiment 1 mentioned above, and description is abbreviate | omitted.

  As shown in FIG. 3, the steam system 10 according to the present embodiment is provided with a plurality of load devices 13A and 13B. The number of load devices may be two or more as shown in FIG.

  A second steam supply line (steam supply line) L12 connected to the steam header 12 is branched and provided so as to be connected to the load devices 13A and 13B. Further, the drain supply line L14 connected to the flash tank 23 is provided to be branched so as to be connected to the load devices 13A and 13B. That is, in the steam system 10 according to the present embodiment, the load devices 13A and 13B are connected in parallel between the second steam supply line L12 on the steam header 12 side and the drain supply line L14 on the flash tank 23 side. Is provided.

  The second steam supply line L12 is provided with a steam flow rate control valve (steam flow rate control unit) 41A at a portion branched so as to be connected to the load device 13A. The steam flow rate adjustment valve 41A adjusts the flow rate of the steam 21 passing through the second steam supply line L12. In the second steam supply line L12, a steam pressure sensor (steam pressure detector) 42A is provided between the steam flow control valve 41A and the load device 13A. The steam pressure sensor 42A detects the pressure in the second steam supply line L12 that reaches the load device 13A via the steam flow rate adjustment valve 41A. Here, the steam flow rate adjusting valve 41A is based on the electrical signal (pressure detection signal) input from the steam pressure sensor 42A, and the flow rate of the steam 21 sent to the load device 13A is a flow rate suitable for the operation of the load device 13A. It is controlled autonomously or by a controller (not shown).

  The second steam supply line L12 is provided with a steam flow rate control valve (steam flow rate control unit) 41B at a portion branched so as to be connected to the load device 13B. The steam flow rate adjusting valve 41B is for adjusting the flow rate of the steam 21 passing through the second steam supply line L12. In the second steam supply line L12, a steam pressure sensor (steam pressure detector) 42B is provided between the steam flow rate adjustment valve 41B and the load device 13B. The steam pressure sensor 42B detects the pressure in the second steam supply line L12 that reaches the load device 13B via the steam flow rate adjustment valve 41B. Here, the steam flow rate adjusting valve 41B is based on the electric signal (pressure detection signal) input from the steam pressure sensor 42B, and the flow rate of the steam 21 sent to the load device 13B is a flow rate suitable for the operation of the load device 13B. It is controlled autonomously or by a controller (not shown).

  The second steam supply line L12 is provided in a portion before the steam flow sensor (steam flow rate detection unit) 43 branches so as to be connected to the load devices 13A and 13B. The steam flow sensor 43 detects the flow rate of the steam 21 adjusted by the steam flow control valves 41A and 41B.

  The drain supply line L14 is provided with a steam trap 24A at a portion branched so as to be connected to the load device 13A. The steam trap 24A passes only the drain 22 discharged from the load device 13A. Therefore, only the drain 22 discharged from the load device 13A through the drain supply line L14 and passing through the steam trap 24A is supplied to the flash tank 23.

  Further, the drain supply line L14 is provided with a steam trap 24B at a portion branched so as to be connected to the load device 13B. The steam trap 24B allows only the drain 22 discharged from the load device 13B to pass through. Therefore, only the drain 22 discharged from the load device 13B through the drain supply line L14 and passing through the steam trap 24B is supplied to the flash tank 23.

  Further, the bypass line L15 is connected to a portion where the drain supply line L14 joins the flash tank 23 side.

  As shown in FIG. 3, the drain recovery system 16 includes a flash tank (drain recovery tank) 23, a flash steam discharge line L21, a flash steam control valve V21, a drain discharge line L22, and a drain discharge valve (drain control unit). ) V22, a drain drain line comprising a bypass line L15, a bypass drain discharge line L16 and a blow drain line L23, a bypass drain drain valve (drain drain valve) V13, a water level detector (water level detector) 34, and a temperature sensor (Temperature detection part) 35, the flash tank pressure sensor 36, and the control apparatus (control part) 37 are provided. About these structures, it is the same as that of Embodiment 1 mentioned above.

  The control device 37 controls the drain collection system 16. The control device 37 is a computer including a CPU and a memory, for example. In this embodiment, the control device 37 outputs a control signal for controlling the opening degree of the drain discharge valve V22. Further, the control device 37 outputs a control signal for controlling the opening / closing of the bypass drain drain valve V13. Further, the control device 37 outputs a control signal for controlling the opening / closing of the bypass discharge valve V11. Further, the control device 37 is electrically connected to the water level sensor 34C, the temperature sensor 35, the steam pressure sensors 42A and 42B, the steam flow rate sensor 43, and the flash tank pressure sensor 36 of the water level detector 34, and each sensor 34C, 35, Based on the electrical signals input from 42A, 42B, 43, 36, the drain recovery system 16 is controlled.

  When the control device 37 outputs a control signal to the drain discharge valve V22, the control device 37 stores the control signal in a memory. Specifically, the control device 37 stores the control signal output to the drain discharge valve V22 during the steady operation of the load device 13A. Further, the control device 37 stores the control signal output to the drain discharge valve V22 during the steady operation of the load device 13B. Furthermore, the control device 37 stores the control signal output to the drain discharge valve V22 during the steady operation of the load devices 13A and 13B that are operated simultaneously. The steady operation of the load devices 13A and 13B is a state in which the load devices 13A and 13B are stably operated continuously. In the load device 13A, the steam flow rate adjusting valve 41A is set to a constant opening degree, and a constant flow rate of the steam 21 is supplied to the load device 13A, whereby the constant flow rate drain 22 is discharged from the load device 13A in a steady operation. It's time. Further, in the load device 13B, the steam flow rate adjustment valve 41B is set to a constant opening degree, and a constant flow rate of the steam 21 is supplied to the load device 13B, whereby the constant flow rate drain 22 is discharged from the load device 13B. This is called steady operation. Further, the control device 37 sets the drain discharge valve V22 when the operation of the load device 13A is stopped, when the operation of the load device 13B is stopped, or when the operation of the load devices 13A and 13B operated simultaneously is stopped. The output control signal is updated and stored.

  In addition, the control device 37 stores information on the set water level of the drain 22 in the flash tank 23 in advance in the memory. The set water level of the drain 22 is a range of the water level of the drain 22 necessary for generating the flash steam 28 for operating the flash steam utilization load device 15. Whether or not the water level of the drain 22 is the set water level is acquired from an electrical signal (water level signal) input from the water level sensor 34C.

  In the control device 37, information on the set temperature of the drain 22 is stored in advance in the memory. The set temperature of the temperature of the drain 22 is for discharging the drain 22 in the initial operation of the load device 13. Whether or not the temperature of the drain 22 is a set temperature is acquired from an electric signal (temperature detection signal) input from the temperature sensor 35.

  In addition, the control device 37 can obtain the operating state of the load device 13A with reference to an electrical signal input from the steam flow rate adjustment valve 41A and an electrical signal (pressure detection signal) input from the steam pressure sensor 42A. it can. As described above, the steam flow rate adjustment valve 41A is suitable for the operation of the load device 13A because the flow rate of the steam 21 sent to the load device 13A is based on the electrical signal (pressure detection signal) input from the steam pressure sensor 42A. The flow rate is controlled autonomously or by a controller (not shown) so that the flow rate becomes high. That is, the control device 37 obtains whether the operating state of the load device 13A is a steady operation by referring to the electrical signal input from the steam flow rate adjustment valve 41A and the electrical signal input from the steam pressure sensor 42A. And a change in the operating state of the load device 13A can be acquired.

  In addition, the control device 37 can acquire the operating state of the load device 13B with reference to the electrical signal input from the steam flow rate adjustment valve 41B and the electrical signal (pressure detection signal) input from the steam pressure sensor 42B. it can. As described above, the steam flow rate adjustment valve 41B is suitable for the operation of the load device 13B because the flow rate of the steam 21 sent to the load device 13B is based on the electric signal (pressure detection signal) input from the steam pressure sensor 42B. The flow rate is controlled autonomously or by a controller (not shown) so that the flow rate becomes high. That is, the control device 37 refers to the electrical signal input from the steam flow rate adjustment valve 41B and the electrical signal input from the steam pressure sensor 42B, and acquires whether the operating state of the load device 13B is a steady operation. And a change in the operating state of the load device 13B can be acquired.

  Further, the control device 37 acquires the operating state of the load devices 13A and 13B from the flow rate of the steam 21 flowing through the second steam supply line L12 based on the electrical signal (flow rate detection signal) input from the steam flow rate sensor 43. Can do. That is, the control device 37 can acquire whether or not the operation state of the load devices 13A and 13B is a steady operation based on the electrical signal input from the steam flow sensor 43, and the operation state of the load devices 13A and 13B. Changes can be obtained. The change in the operating state of the load device 13 is one of an electrical signal input from the steam flow rate control valve 41, an electrical signal input from the steam pressure sensor 42, or an electrical signal input from the steam flow rate sensor 43. You can get more.

  FIG. 4 is a flowchart showing the control of the drain discharge valve V22 by the control device 37. FIG. 4 shows a procedure for stopping the load devices 13A and 13B described above from starting. In the present embodiment, when the load devices 13A and 13B are started, the steam 21 is generated by the boiler 11, and the steam 21 necessary for operating the load devices 13A and 13B is stored in the steam header 12. Suppose that In addition, before the load devices 13A and 13B are activated, the steam flow rate control valves 41A and 41B provided in the second steam supply line L12 are closed. Further, the bypass drain drain valve V13 of the bypass drain discharge line L16 is closed before the load devices 13A and 13B are started. Further, the bypass discharge valve V11 of the bypass line L15 is in a closed state. Further, the blow discharge valve V23 of the blow discharge line L23 is in a closed state. Further, before the activation of the load devices 13A and 13B, the control device 37 stores in advance a control signal output to the drain discharge valve V22 during the normal operation of the immediately preceding load devices 13A and 13B (single or all).

  When starting the load devices 13A and 13B, the steam 21 is supplied to the load devices 13A and 13B through the second steam supply line L12 by opening predetermined steam flow rate control valves 41A and 41B. Here, opening of the predetermined steam flow rate control valves 41A and 41B means that only the steam flow rate control valve 41A is opened, only the steam flow rate control valve 41B is opened, or all the steam flow rate control valves 41A, This means that 41B can be opened. The drain 22 generated in the load devices 13A and 13B is supplied to the flash tank 23 through the drain supply line L14. At this time, the control device 37 acquires the electrical signal (temperature detection signal) input from the temperature sensor 35, and if the temperature of the drain 22 is equal to or higher than the set temperature (step S21: Yes), the bypass drain drain valve V13 is set. If it is kept closed (step S22) and the temperature of the drain 22 is lower than the set temperature (step S21: No), the bypass drain drain valve V13 is opened (step S23). Note that when the bypass drain drain valve V13 is opened in step S23, the control device 37 keeps the bypass drain drain valve V13 open until the temperature of the drain 22 becomes equal to or higher than the set temperature. In step S23, by opening the bypass drain drain valve V13, the drain 22 is drained without passing through the flash tank 23 through the drain drain line including the bypass drain discharge line L16. The drain 22 discharged when the operation of the load device 13 is in an initial stage is low in temperature and often contains a large amount of impurities such as sludge and rust, and air. Therefore, even if the drain 22 discharged in the initial stage of the operation of the load device 13 is recovered by the flash tank 23 and supplied to the water supply tank 14, it is difficult to use it in the boiler 11. Therefore, when the load devices 13A and 13B are activated, the drain 22 having such a low temperature is drained without passing through the flash tank 23.

  Next, after the bypass drain drain valve V13 is closed in step S2, the water level of the drain 22 becomes the set water level by obtaining an electric signal (water level signal) input from the water level sensor 34C (step S24: Yes). The control device 37 adjusts the drain discharge valve V22 to a previously stored opening degree (step S25). By closing the bypass drain drain valve V13, drainage of the drain 22 through the drain drain line including the bypass drain discharge line L16 is stopped, and the drain 22 is supplied and stored in the flash tank 23. When the water level of the drain 22 reaches the set water level, the water level of the drain 22 accumulated in the flash tank 23 is kept constant within the range of the set water level by adjusting the drain discharge valve V22 to a previously stored opening. It will be. Further, until the water level of the drain 22 reaches the set water level (step S24: No), the control device 37 maintains the drain discharge valve V22 in a closed state.

  In step S25, after adjusting the drain discharge valve V22 to the opening stored in advance, if the operation of all the load devices 13 is not stopped (step S26: No), the operation of the load devices 13 is continued. The control device 37 continues this control while maintaining the opening degree of the drain discharge valve V22 adjusted in step S25. Whether or not the operation of all the load devices 13 is stopped is determined by an electric signal input from the steam flow control valve 41 (when closed), an electric signal input from the steam pressure sensor 42, or an input from the steam flow sensor 43. Any one of the electrical signals to be obtained can be obtained from one.

  In step S26, the operation of all the load devices 13 during operation is not stopped (step S26: No), and the operation state of the load devices 13A and 13B changes while the operation of the load device 13 is continued. There is a case. In this case, the water level of the drain 22 in the flash tank 23 changes. Specifically, when the water level of the drain 22 acquired by the electrical signal (water level signal) input from the water level sensor 34C is constant within the set water level range (step S27: Yes), the control device 37 adjusts in step S25. The opening degree of the drain discharge valve V22 thus maintained is maintained (step S28). On the other hand, when the water level of the drain 22 is not constant (step S27: No) and rises (step S29: Yes), the control device 37 largely adjusts the opening degree of the drain discharge valve V22 (step S30). Thereby, the discharge amount of the drain 22 flowing into the water supply tank 14 through the drain discharge line L22 increases, and the water level of the drain 22 accumulated in the flash tank 23 is kept constant. Further, when the water level of the drain 22 is not raised (step S29: No) but lowered (step S31: Yes), the control device 37 adjusts the opening of the drain discharge valve V22 to be small (step S32). Thereby, the discharge amount of the drain 22 flowing into the water supply tank 14 through the drain discharge line L22 is reduced, and the water level of the drain 22 accumulated in the flash tank 23 is kept constant. In addition, after adjusting the opening degree of the drain discharge valve V22 in step S30 or step S32, the opening degree of the drain discharge valve V22 may be maintained by reaching step S28, but as shown in FIG. 4, the process returns to step S26. If the operation of all the load devices 13 in operation is not stopped (step S26: No), it is preferable to check the water level of the drain 22 in step S27.

  In step S27, after maintaining the opening degree of the drain discharge valve V22, if all the load devices 13 in operation are in steady operation (step S33: Yes), the control device 37 drains the drain discharge valve V22 in steady operation. Is stored and updated (step S34). When there are a plurality of openings of the drain discharge valve V22 stored in step S34, all the openings are stored. After step S34, the process returns to step S26, and if the operation of all the load devices 13 in operation is not stopped (step S26: No), the water level of the drain 22 is confirmed in step S27. On the other hand, if all the load devices 13 in operation are not in steady operation in step S33 (step S33: No), the control device 37 returns to step S26 and stops the operation of all the load devices 13 in operation. If not (Step S26: No), the water level of the drain 22 is confirmed in Step S27.

  In step S <b> 33, the determination of the steady operation of the load devices 13 </ b> A and 13 </ b> B is acquired based on an electrical signal (flow rate detection signal) input from the steam flow rate sensor 43. Alternatively, the determination of the steady operation of the load devices 13A and 13B can be obtained by referring to the electrical signals input from the steam flow rate control valves 41A and 41B and the electrical signals input from the steam pressure sensors 42A and 42B. Alternatively, the determination of the steady operation of the load devices 13A and 13B may be acquired based on an electric signal input from a controller (not shown) that controls the load devices 13A and 13B. Alternatively, the determination of the steady operation of the load devices 13A and 13B is based on the control signal of the control device 37 itself that maintains the drain discharge valve V22 at a predetermined opening for a predetermined time based on the control signal for controlling the drain discharge valve V22. You can get it.

  Note that when the drain 22 accumulates in the flash tank 23, flash vapor 28 is generated from the drain 22. Therefore, the control device 37 opens the flash steam control valve V21 and feeds the flash steam 28 to the flash steam utilization load device 15 through the flash steam discharge line L21. Thereby, the flash steam 28 is used as a heating source or a power source of the flash steam utilization load device 15. At this time, the control device 37 adjusts the opening degree of the flash steam control valve V21 based on the electric signal (flash steam pressure detection signal) input from the flash tank pressure sensor 36.

  By the way, in step S26, when the operation of all the load devices 13A and 13B in operation is stopped (step S26: Yes), the opening of the drain discharge valve V22 stored in step S34 is the drain used in step S25. When there is a change in the opening degree of the discharge valve V22 (step S35: Yes), the opening degree of the control device 37 is maintained most continuously from when the load devices 13A and 13B are started to when they are stopped. The control signal output to the drain discharge valve V22 at that time, that is, the opening degree of the drain discharge valve V22 during the steady operation that was most stable is stored and updated (step S36), and this control is terminated. The control signal (opening degree of the drain discharge valve V22) to the drain discharge valve V22 that is stored and updated is applied to the next operation of the load devices 13A and 13B. The control signal (opening degree of the drain discharge valve V22) to the drain discharge valve V22 stored and updated here is the one during the steady operation of the load devices 13A and 13B (single or all). That is, when the operation is performed only by the load device 13A, it becomes a control signal to the drain discharge valve V22 (the opening degree of the drain discharge valve V22) at the time of steady operation of only the load device 13A, and this is the only load device 13A. Applies when driving. Further, when the operation is performed only by the load device 13B, the control signal to the drain discharge valve V22 (the opening degree of the drain discharge valve V22) at the time of steady operation of only the load device 13B becomes the only load device 13B. Applies when driving. Further, when all the load devices 13A and 13B are operated, the control signal to the drain discharge valve V22 during the steady operation of all the load devices 13A and 13B (the opening degree of the drain discharge valve V22) is obtained. This is applied when all the following load devices 13A and 13B are operated. On the other hand, when there is no change in the stored opening degree of the drain discharge valve V22 (step S35: No), the control device 37 keeps storing the opening degree of the drain discharge valve V22 used in step S25 and does not update it. End control.

  As described above, the drain recovery system 16 according to the present embodiment is a flash tank that recovers the drain 22 discharged from the plurality of load devices 13A and 13B that use the steam 21 supplied from the boiler (steam supply source) 11. A drain recovery tank) 23, a drain discharge line L22 for guiding the drain 22 to the outside of the flash tank 23, and a drain discharge for adjusting the flow rate of the drain 22 provided in the drain discharge line L22 and flowing through the drain discharge line L22 according to the opening of the valve. The opening of the drain discharge valve V22 during steady operation is stored for each combination of the valve (drain adjustment unit) V22 and the operation of each of the single or plural load devices 13A and 13B, and the drain 22 is discharged outside the flash tank 23. , The degree of opening that stores the degree of opening of the drain discharge valve V22 by controlling the drain discharge valve V22 Adjusting controlling device having (control unit) 37, a.

  According to this drain recovery system 16, the opening degree of the drain discharge valve V <b> 22 at the time of steady operation is stored in advance for each combination of operation of a single or a plurality of load devices 13 </ b> A, 13 </ b> B, and Since the opening degree of the drain discharge valve V22 is adjusted to the stored opening degree when the discharge of the drain 22 is started, the opening / closing frequency of the drain discharge valve V22 and the load devices 13A, 13B until the steady operation is performed. The frequency of adjusting the opening degree of the drain discharge valve V22 can be reduced, and the life of the valve can be further extended. Moreover, when the opening degree of the drain discharge valve V22 is adjusted in accordance with the water level of the drain 22 in the flash tank 23 until the plurality of load devices 13A and 13B reach the steady operation, the drain discharge is caused by a sudden load fluctuation. Although the valve V22 may cause hunting, according to the drain recovery system 16 of the present embodiment, when the drain 22 is started to be discharged out of the flash tank 23, the opening of the drain discharge valve V22 is stored. By adjusting to, such a situation can be prevented.

  Further, the drain recovery system 16 according to the present embodiment includes a water level detector (water level detection unit) 34 that is provided in the flash tank 23 and detects the water level of the drain 22 in the flash tank 23. When opening the drain discharge valve V22 during steady operation of the load devices 13A and 13B and starting the discharge of the drain 22 outside the flash tank 23, the opening of the drain discharge valve V22 is controlled by controlling the drain discharge valve V22. The drain discharge valve V22 is controlled based on the water level in the flash tank 23 detected by the water level detector 34, and the drain discharge valve V22 is opened when the water level of the drain 22 rises. When the water level of the drain 22 decreases, the degree of opening of the drain discharge valve V22 is decreased.

  After the load devices 13A and 13B are in a steady operation, the change in the operation state of the load devices 13A and 13B is small, so the amount of discharge of the drain 22 is small and the fluctuation range of the water level of the drain 22 in the flash tank 23 is small. Therefore, according to the drain recovery system 16, it is only necessary to finely adjust the opening degree of the drain discharge valve V22 stored and controlled in advance, and the frequency of adjusting the opening degree of the drain discharge valve V22 is reduced, and the flush tank 23 is adjusted. The water level of the accumulated drain 22 can be kept within a predetermined range.

  Further, in the drain recovery system 16 according to the present embodiment, the control device 37 determines the opening degree of the drain discharge valve V22 during the steady operation of the plurality of load devices 13A and 13B when the operation of the plurality of load devices 13A and 13B is stopped. Update and remember.

  According to this drain recovery system 16, the opening degree of the drain discharge valve V22 at the time of steady operation is stored for each combination of operation of each of the load devices 13A and 13B when the operation is stopped, and single or plural Since it is used at the time of the next operation of each load device 13A, 13B, the opening degree of the drain discharge valve V22 according to the discharge amount of the drain 22 discharged according to the current state of each load device 13A, 13B can be set. Further, the opening / closing frequency of the drain discharge valve V22 and the frequency of adjusting the opening degree of the drain discharge valve V22 can be further reduced, and the effect of further extending the life of the valve can be remarkably obtained.

  In addition, this invention is not limited to each embodiment mentioned above, A various change is possible in the range which does not deviate from the meaning of invention. For example, in the first and second embodiments, the water level detector 34 employs a float method, but is not limited to this, and a known water level detection method such as an electrode rod method using an electrode rod or a water pressure detection method. You may use the apparatus which employ | adopted. In the first and second embodiments, the blow discharge line L23 is branched from the drain discharge line L22. However, the present invention is not limited to this, and the drain discharge line L22 and the blow discharge line L23 are respectively provided in the flash tank 23. It may be connected.

10 Steam system 11 Boiler (steam supply source)
13 (13A, 13B) Load device 16 Drain recovery system 21 Steam 22 Drain 23 Flash tank (drain recovery tank)
34 Water level detector (water level detector)
37 Control device (control unit)
L12 Second steam supply line (steam supply line)
L14 Drain supply line L22 Drain discharge line V22 Drain discharge valve (drain control unit)

Claims (4)

A drain recovery tank for recovering drain discharged from load equipment that uses steam supplied from a steam supply source;
A drain discharge line for guiding the drain to the outside of the drain recovery tank;
A drain adjuster that is provided in the drain discharge line and adjusts the flow rate of the drain flowing through the drain discharge line according to the opening of a valve;
Stores the opening of the valve at the time of steady operation of the load device, and when starting to discharge the drain outside the drain recovery tank, the opening that stores the opening of the valve by controlling the drain adjustment unit A control unit to adjust to,
A drain recovery system comprising: A water level detector provided in the drain recovery tank for detecting the level of the drain in the drain recovery tank;
The control unit stores an opening degree of the valve at the time of steady operation of the load device, and when discharging the drain outside the drain recovery tank, controls the drain adjusting unit to control the opening degree of the valve. And adjusting the drain adjustment unit based on the water level in the drain recovery tank detected by the water level detection unit, the valve opening when the water level of the drain rises The drain recovery system according to claim 1, wherein when the water level of the drain is lowered, the opening of the valve is reduced.   The said control part updates and memorize | stores the opening degree of the said valve | bulb of the said drain adjustment part at the time of the steady operation of the said load apparatus at the time of the driving | operation stop of the said load apparatus. Drain collection system. A plurality of the load devices are provided,
The drain recovery tank is supplied with drain discharged from each load device,
The control unit stores the opening degree of the valve of the drain adjustment unit during steady operation for each combination of operation of the single or plural load devices, and starts discharging the drain out of the drain recovery tank. The drain recovery system according to any one of claims 1 to 3, wherein when the control is performed, the drain adjustment unit is controlled to adjust the opening of the valve to the stored opening.

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