JP6187005B2 - Boiler system - Google Patents

Description

  The present invention relates to a boiler system. Specifically, the present invention relates to a closed-type boiler system that collects drain discharged from a load device without supplying it to the atmosphere and supplies water to the boiler.

  Conventionally, steam generated by a boiler is supplied to load equipment, and the drain generated by condensation of steam used as a heat source in the load equipment is stored in a pressure-resistant sealed drain recovery tank at high temperature and pressure. A closed-type boiler system that collects and supplies water to the boiler again has been proposed (see, for example, Patent Document 1).

JP 2006-105442 A

Here, the closed type boiler system disclosed in Patent Document 1 has a water level detection device that detects the water level in the drain recovery tank, and when the drain amount in the drain recovery tank decreases, the makeup water is drained. It is configured to be supplied into the tank.
However, in this case, the temperature of the drain in the drain recovery tank is lowered, which is not preferable from the viewpoint of thermal efficiency.

On the other hand, when the drain amount in a drain collection tank decreases, the structure which supplies makeup water to a drain supply line or a boiler can be considered.
However, in this case, even if the level of the drain recovery tank is detected and makeup water is supplied, the amount of drain supplied to the boiler is not adjusted. For example, the amount of drain supplied to the boiler is insufficient. It was not intended to suppress damage caused by overheating of the boiler.

  An object of this invention is to provide the closed type boiler system which can suppress generation | occurrence | production of the malfunction which arises when the amount of drain supplied to a boiler is insufficient.

  The present invention includes a boiler that generates steam and supplies the generated steam to a load device, and the drain generated by the load device condensing by using the steam without opening it to the atmosphere. A drain-type boiler system comprising: a drain tank to be recovered; and a drain supply line that connects the drain tank and the boiler and feeds water contained in the drain tank to the boiler. A drain liquid feeding unit that feeds the drain accommodated in the drain tank to the boiler, and a drain flow rate detection unit that is arranged in the drain supply line and detects the flow rate of the drain supplied to the boiler, A makeup water tank for storing makeup water, the makeup water tank and the boiler are connected, or the makeup water tank and the drain supply line are connected to each other. Are connected to the boiler directly or via the drain supply line, and the supplementary water supply line is disposed in the supplementary water tank. A makeup water feeding section for feeding the contained makeup water directly to the boiler or via the drain supply line, and the makeup water feeding section based on the drain flow rate detected by the drain flow rate detection section. And a control unit that controls the boiler system.

  In the boiler system of the present invention, the control unit may be configured such that the drain flow rate detected by the drain flow rate detection unit is less than a predetermined flow rate threshold value in a liquid feeding state in which the drain liquid feeding unit feeds the drain. In this case, it is preferable to control the replenishing water feeding unit so as to start the feeding of replenishing water.

  The boiler system according to the present invention further includes a water level detection unit that detects a water level in the boiler, and the control unit supplies the liquid supply state or drain based on the water level detected by the water level detection unit. It is preferable to control the drain liquid feeding section so as to change the state to a non-liquid feeding state where liquid does not flow.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the closed type boiler system which can suppress generation | occurrence | production of the malfunction which arises when the amount of drain supplied to a boiler is insufficient.

It is a figure showing the composition of the boiler system concerning one embodiment of the present invention. It is a vertical direction sectional view of the can of a once-through boiler. It is the sectional view on the AA line of FIG. It is a flowchart explaining operation | movement of a boiler system.

Hereinafter, a preferred embodiment of a boiler system of the present invention will be described with reference to the drawings.
First, the configuration of the boiler system 1 will be described with reference to FIGS. 1 to 3. FIG. 1 is a diagram showing a configuration of a boiler system 1 according to an embodiment of the present invention. FIG. 2 is a vertical sectional view of the can of the once-through boiler. FIG. 3 is a cross-sectional view taken along line AA in FIG.
As shown in FIG. 1, the boiler system 1 of the present embodiment includes a boiler device 70 including a once-through boiler 10 and a closed-type drain recovery device 20.

  As shown in FIG. 1, the boiler device 70 includes a once-through boiler 10, a steam header 71 where steam generated in the once-through boiler 10 is collected, and a connecting pipe 72 that connects the once-through boiler 10 and the steam header 71. Prepare.

The once-through boiler 10 generates steam by heating the feed water supplied therein with combustion gas, and supplies the generated steam to a load device 50 described later.
In the present embodiment, the drain recovered by the drain recovery device 20 is supplied as feed water to the once-through boiler 10 (a plurality of water pipes). Specifically, the once-through boiler 10 (a plurality of water pipes) is supplied with drain water stored in a drain tank 21 described later, makeup water stored in an open tank 22 described later, or a mixed water of drain and makeup water as supply water. Is done.

  As shown in FIGS. 2 and 3, the once-through boiler 10 includes a can 11, a plurality of water pipes 12, a connection wall 13, a lower header 14, an upper header 15, a duct 16, a burner 17, A cylinder 18 and a water level detector 19 are provided.

The can body 11 is configured in a rectangular parallelepiped shape in a plan view.
The plurality of water pipes 12 are arranged extending in the vertical direction inside the can body 11 and are arranged at predetermined intervals in the longitudinal direction and the width direction of the can body 11.
In the present embodiment, the plurality of water pipes 12 are arranged on the outer side in the width direction, on the outer side water pipe group 12a disposed along the side part extending in the longitudinal direction of the can body 11, and in the center part in the width direction of the can body 11. It is classified into a central water tube group 12b arranged along the longitudinal direction, and an intermediate water tube group 12c arranged between the outer water tube group 12a and the central water tube group 12b.
The connection wall 13 connects the water pipes 12 arranged adjacent to each other in the outer water pipe group 12a.

  The lower header 14 is configured by a rectangular parallelepiped container having a rectangular shape in plan view, and is disposed at the lower portion of the can 11. The lower header 14 is connected to lower ends of the plurality of water pipes 12. Drain is supplied to the lower header 14 from the drain recovery device 20, and drain is supplied from the lower header 14 to the plurality of water pipes 12.

  The upper header 15 is configured by a rectangular parallelepiped container having a rectangular shape in plan view, and is disposed on the upper portion of the can body 11. The upper header 15 is connected to the upper ends of the plurality of water pipes 12. Steam generated in the plurality of water pipes 12 is collected in the upper header 15. A connecting pipe 72 (see FIG. 1) is connected to the upper header 15, and the steam collected in the upper header 15 is supplied to the steam header 71 through the connecting pipe 72.

  The duct 16 is connected to a lower portion of the first side surface 11 a located on one end side in the longitudinal direction of the can body 11. Connected to the upstream side of the duct 16 are a fuel supply unit (not shown) to which fuel gas is supplied and a blower (not shown) for supplying combustion air. The duct 16 mixes the fuel gas supplied from the fuel supply unit and the combustion air supplied from the blower and supplies the mixed gas toward the inside of the can body 11.

As shown in FIG. 2, in the present embodiment, the duct 16 includes a downward air supply passage portion 162 that extends in the vertical direction and through which combustion air flows downward.
According to the above duct 16, the combustion air sent out from the blower flows through the downward air supply path portion 162 downward and is supplied to the can body 11.

  The burner 17 is arrange | positioned in the connection part of the duct 16 and the can 11 in the 1st side surface 11a. The burner 17 ejects a mixed gas in which combustion air and fuel are mixed from the duct 16 into the can 11 and burns the mixed gas.

  The exhaust cylinder 18 is connected to the second side surface 11b located on the other end side in the longitudinal direction of the can body 11 (the side opposite to the side where the duct 16 is provided). The exhaust cylinder 18 discharges the combustion gas generated by burning the mixed gas inside the can 11.

As shown in FIG. 2, in the present embodiment, the exhaust cylinder 18 includes an upward exhaust passage portion 181 that extends upward from a connection portion with the can body 11.
According to the exhaust cylinder 18 described above, the combustion gas discharged from the can 11 flows through the upward exhaust passage 181 upward and is discharged to the outside.

The water level detection unit 19 detects the water level in the once-through boiler 10. The water level detection unit 19 determines the water level based on a sealed storage unit 19a, one or more electrode bars (not shown) stored in the storage unit 19a, and information from the electrode bars (information on electrical conductivity). A detection unit (substrate or the like) for detection.
Further, the water level detection unit 19 communicates the first communication pipe 19b that communicates the housing part 19a with the lower header 14 in the once-through boiler 10 and the second communication pipe 19c that communicates the housing part 19a and the upper header 15 in the once-through boiler 10. The accommodating portion 19a and the plurality of water pipes 12 are communicated with each other through the lower header 14 and the upper header 15.

As shown in FIG. 1, the steam generated in the once-through boiler 10 is supplied to the steam header 71 through a connecting pipe 72. The steam header 71 stores the steam generated by the once-through boiler 10 and supplies the steam to the load device 50.
The load device 50 uses the steam generated by the once-through boiler 10 as a heat source, and performs heat exchange with the object to be heated.

Subsequently, the drain recovery device 20 recovers the drain generated by condensing the steam generated by the once-through boiler 10 in the load device 50 in a high temperature / high pressure state, and uses the recovered drain as feed water. It is supplied again to the once-through boiler 10.
The drain recovery device 20 includes a drain tank 21, an open tank 22 (makeup water tank), a first steam supply line L1, a first drain supply line L2, and a second drain supply line L3 (drain supply line), A second steam supply line L4, a flash steam discharge line L5, a makeup water supply line L6 (a makeup water supply line), and a control unit 100 are provided.

  The drain tank 21 collects and stores the drain generated by condensation of a part of the steam used for heat exchange in the load device 50. The drain tank 21 collects the drain without opening it to the atmosphere. The drain tank 21 is composed of a pressure vessel that has pressure resistance and can be sealed.

  The open tank 22 is open to the atmosphere. The open tank 22 stores (accommodates) makeup water supplied to the once-through boiler 10. Further, the open tank 22 is introduced with flash steam generated from the drain in the drain tank 21.

The first steam supply line L <b> 1 connects the steam header 71 and the load device 50, and supplies the steam generated by the once-through boiler 10 to the load device 50.
The first drain supply line L <b> 2 connects the load device 50 and the drain tank 21, and supplies the drain generated in the load device 50 to the drain tank 21. In the first drain supply line L2, a steam trap 61, a check valve 62, and a motor valve 63 that discharge drain generated in the load device 50 and prevent discharge of steam are disposed.

  The second drain supply line L3 connects the drain tank 21 and the once-through boiler 10, and supplies the drain accommodated in the drain tank 21 to the once-through boiler 10. In the present embodiment, the upstream end of the second drain supply line L <b> 3 is connected to the lower portion of the drain tank 21. Further, the downstream side of the second drain supply line L <b> 3 is connected to the can 11.

The second drain supply line L3 includes an upstream portion L3a, a connecting portion L3b, and a downstream portion L3c.
The upstream portion L3a is a portion on the upstream side in the second drain supply line L3, and is a portion between the drain tank 21 and the connecting portion L3b.
A drain flow meter 80 and a drain supply valve 81 are arranged in the upstream portion L3a.

The drain flow meter 80 detects the flow rate of the drain supplied from the drain tank 21 to the once-through boiler 10.
The drain flow meter 80 outputs information on the detected drain flow rate to the control unit 100 described later.

  In the present embodiment, the drain supply valve 81 is configured by a motor valve. The drain supply valve 81 is configured to be switchable between an open state in which drain is supplied from the drain tank 21 to the once-through boiler 10 and a closed state in which drain is not supplied from the drain tank 21 to the once-through boiler 10. The drain supply valve 81 is switched between an open state and a closed state by a control unit 100 described later.

  The connecting portion L3b is a portion that is disposed between the upstream portion L3a and the downstream portion L3c and connected to the makeup water supply line L6. The makeup water supplied from the makeup water supply line L6 at the connecting portion L3b is supplied to the second drain supply line L3.

The downstream portion L3c is a portion on the downstream side in the second drain supply line L3, and is a portion between the connecting portion L3b and the once-through boiler 10.
The downstream portion L3c passes the drain from the drain tank 21, the makeup water from the open tank 22, or the mixed water of the makeup water and the drain mixed in the connecting portion L3b, and supplies them to the once-through boiler 10.
A drain pump 64 and a supply valve 65 are disposed in the downstream portion L3c.

The drain pump 64 boosts the drain from the drain tank 21 and supplies it to the once-through boiler 10. Specifically, the drain pump 64 boosts the drain from the drain tank 21, the makeup water from the open tank 22, or the mixed water of the makeup water and the drain mixed at the connecting portion L <b> 3 b and supplies the boosted water to the once-through boiler 10. To do.
In the present embodiment, the supply valve 65 is constituted by a motor valve, and adjusts the amount of drain or the like supplied to the once-through boiler 10.

Here, the drain supply valve 81 and the drain pump 64 constitute a drain liquid feeding unit that feeds the drain accommodated in the drain tank 21 to the once-through boiler 10.
The drain liquid feeding unit is configured to be able to change the state between a liquid feeding state in which drain is fed and a non-liquid feeding state in which drain is not fed. The drain liquid feeding unit is controlled to be switched between a liquid feeding state and a non-liquid feeding state by a control unit 100 described later.

  The second steam supply line L4 connects the steam header 71 and the drain tank 21. The second steam supply line L <b> 4 supplies the steam generated by the once-through boiler 10 to the drain tank 21 via the steam header 71 and adjusts the pressure inside the drain tank 21. A pressure adjustment valve 66 and a motor valve 67 are disposed in the second steam supply line L4.

  The flash steam discharge line L5 connects the drain tank 21 and the open tank 22, and discharges the flash steam generated in the drain tank 21 to the open tank 22. A pressure regulating valve 68 is disposed in the flash steam discharge line L5. When the pressure inside the drain tank 21 exceeds a predetermined pressure, the pressure regulating valve 68 releases the flash vapor to the open tank 22 side and reduces the pressure inside the drain tank 21.

The makeup water supply line L6 connects the open tank 22 and the second drain supply line L3, and supplies makeup water stored in the open tank 22 to the plurality of once-through boilers 10 via the second drain supply line L3. .
Specifically, the makeup water supply line L6 connects the open tank 22 and the connecting portion L3b in the second drain supply line L3. And the makeup water supply line L6 supplies the makeup water stored in the open tank 22 to the once-through boiler 10 via the downstream portion L3c in the second drain supply line L3.

A makeup water pump 69 (a makeup water feeding section) is disposed in the makeup water supply line L6.
The makeup water pump 69 supplies (liquid feed) the makeup water stored (accommodated) in the open tank 22 to the once-through boiler 10 via the second drain supply line L3.
The makeup water pump 69 is configured to be changeable between an on state in which makeup water is fed and an off state in which makeup water is not fed. The makeup water pump 69 is controlled to be switched between an on state and an off state by the control unit 100 described later.

  Continuously, the control part 100 is comprised so that control of the drain supply valve 81, the drain pump 64, and the makeup water pump 69 is possible.

The control unit 100 changes the state of the drain supply valve 81 between an open state in which the drain (stored) in the drain tank 21 is supplied to the plurality of once-through boilers 10 and a closed state in which the drain is not supplied.
Further, the control unit 100 changes the state of the drain pump 64 between an on state in which the drain stored (accommodated) in the drain tank 21 is fed (supplied) to the once-through boiler 10 and an off state in which the drain is not fed.

And the control part 100 is the drain supply valve 81 and the drain pump 64 (in the liquid feeding state which sends the liquid stored (accommodated) in the drain tank 21 to the once-through boiler 10, and the non-liquid feeding state which does not liquid-feed. Change the state of the drain liquid feeding part).
Specifically, the control unit 100 opens the drain supply valve 81 and turns on the drain pump 64 to bring the drain supply valve 81 and the drain pump 64 (drain liquid feeding unit) into the liquid feeding state. . Moreover, the control part 100 makes the drain supply valve 81 and the drain pump 64 (drain liquid feeding part) non-liquid feeding state by making the drain supply valve 81 into a closed state.

  Furthermore, the control unit 100 is in an on state in which makeup water stored (accommodated) in the open tank 22 is supplied (supplied) to the once-through boiler 10 via the second drain supply line L3 and in an off state in which no liquid is supplied. The state of the makeup water pump 69 is changed.

In the present embodiment, the control unit 100 controls the makeup water pump 69 based on the drain flow rate detected by the drain flow meter 80.
Specifically, the control unit 100 determines that the flow rate of the drain detected by the drain flow meter 80 is predetermined in the liquid supply state in which the drain supply valve 81 and the drain pump 64 (drain liquid supply unit) supply the drain. When the state of less than the flow rate threshold value continues for a predetermined time, the makeup water pump 69 is controlled so as to start feeding makeup water. When the drain supply valve 81 and the drain pump 64 (drain liquid feeding part) are in the liquid feeding state, the control unit 100 sends makeup water when the drain flow rate detected by the drain flow meter 80 is less than a predetermined flow rate threshold value. The makeup water pump 69 is controlled so that the liquid is turned on.

  That is, when the amount of drain supplied to the once-through boiler 10 decreases, the control unit 100 starts supplying makeup water to the makeup water pump 69 in order to prevent the water level in the plurality of once-through boilers 10 from decreasing. Let

  In the present embodiment, the control unit 100 supplies the drain so as to change the state to a liquid feeding state in which drain is fed based on the water level detected by the water level detecting unit 19 or a non-liquid feeding state in which the drain is not fed. The valve 81 and the drain pump 64 (drain liquid feeding part) are controlled. The control unit 100 detects the water level in the once-through boiler 10 based on the information on the water level from the water level detection unit 19, and controls the drain supply valve 81 and the drain pump 64 (drain liquid feeding unit) based on the detected water level. To do.

  Specifically, in the present embodiment, the control unit 100 supplies the drain when the water level detected by the water level detection unit 19 falls below a predetermined water level set according to the plurality of combustion states of the once-through boiler 10. The valve 81 and the drain pump 64 (drain liquid feeding unit) are controlled to be in a liquid feeding state. In addition, when the water level detected by the water level detection unit 19 is equal to or higher than the set predetermined water level (when the boiler water level has risen sufficiently), the control unit 100 drains the drain supply valve 81 and the drain pump 64 (drain liquid feeding unit). Is controlled so as not to feed liquid.

As described above, the control unit 100 includes a drain supply valve 81, a drain pump 64 (drain liquid feeding unit), and a makeup water pump 69 (a makeup water feeding unit) according to the drain supply state, the water level of the once-through boiler 10, and the like. ) And control.
For example, when the water level detected by the water level detection unit 19 decreases, the control unit 100 sets the drain supply valve 81 and the drain pump 64 to the liquid supply state and sets the makeup water pump 69 to the non-liquid supply state. In this case, drain is supplied to the once-through boiler 10.
In addition, in a state where the drain is supplied, when the state where the flow rate of the drain is lower than the predetermined flow rate threshold value continues for a predetermined time, the control unit 100 supplies the makeup water pump 69 to the liquid supply state to compensate for the shortage of the drain amount. To. In this case, the once-through boiler 10 is supplied with mixed water of drain and makeup water.
Then, when the water level detected by the water level detection unit 19 rises, the control unit 100 sets the drain supply valve 81 and the drain pump 64 to the non-liquid supply state and sets the makeup water pump 69 to the non-liquid supply state.

Next, the operation of the boiler system 1 of the present embodiment will be described with reference to FIG. FIG. 4 is a flowchart for explaining the operation of the boiler system.
First, in step ST1, the boiler system 1 receives an instruction to start operation. The control part 100 in the boiler system 1 controls each part so that it may become a normal driving | running state. For example, the control unit 100 turns on the makeup water pump 69 and the drain pump 64 to supply makeup water to each of the plurality of once-through boilers 10, and in the burner 17 based on information on the water level from the water level detection unit 19. Combustion of a mixed gas of combustion gas and combustion air is started.

Subsequently, in step ST <b> 2, the control unit 100 detects whether the water level in the once-through boiler 10 is below a predetermined water level based on the information regarding the water level from the water level detection unit 19.
When it is detected that the water level of once-through boiler 10 is lower than the predetermined water level (step ST2, YES), control unit 100 advances the process to step ST3.
Moreover, the control part 100 returns a process to step ST2, when not detecting that the water level of a boiler is less than the predetermined water level (step ST2, NO).

  Next, in step ST3, the control unit 100 opens the drain supply valve 81. Thereby, the drain is supplied to the plurality of once-through boilers 10. In this state, the makeup water pump 69 is off.

  Subsequently, in step ST4, the drain flow meter 80 outputs information related to the drain flow rate to the control unit 100 continuously or at predetermined time intervals.

In step ST <b> 5, the control unit 100 detects whether the drain flow rate is less than a predetermined threshold flow rate based on information from the drain flow meter 80.
When it is detected that the flow rate of the drain is a predetermined threshold flow rate (step ST5, YES), control unit 100 advances the process to step ST6.
Moreover, the control part 100 returns a process to step ST4, when not detecting that the flow volume of drain is a predetermined | prescribed threshold flow volume (step ST5, NO).

  In step ST6, the control unit 100 turns on the makeup water pump 69. The control unit 100 keeps the drain supply valve 81 in the open state and turns on the makeup water pump 69. Thereby, mixed water of drain and makeup water is supplied to once-through boiler 10.

Subsequently, in step ST7, the control unit 100 detects whether or not the water level in the once-through boiler 10 exceeds a predetermined water level based on the information regarding the water level from the water level detection unit 19.
When the control unit 100 detects that the water level of the once-through boiler 10 exceeds the predetermined water level (step ST7, YES), the control unit 100 advances the process to step ST8.
Moreover, the control part 100 returns a process to step ST7, when not detecting that the water level of a boiler is over the predetermined water level (step ST7, NO).

  Next, in step ST8, the control unit 100 turns off the makeup water pump 69 and closes the drain supply valve 81. Thereby, supply of drain and makeup water to once-through boiler 10 is stopped.

Subsequently, in step ST9, the control unit 100 confirms whether an instruction to stop operation has been received.
If control unit 100 has not received an instruction to stop operation (step ST9, NO), control unit 100 returns the process to step ST2.
Moreover, the control part 100 controls each part so that the driving | operation of the boiler system 1 may be stopped, when the instruction | indication of a driving | operation stop is received (step ST9, YES).

The boiler system 1 according to the present embodiment having the above-described configuration has the following effects.
The boiler system 1 according to the present embodiment is arranged in the second drain supply line L3, and a drain supply valve 81 and a drain pump 64 for feeding the drain accommodated in the drain tank 21 to the once-through boiler 10 boiler, and the second drain supply. A drain flow meter 80 arranged in line L3 for detecting the flow rate of the drain supplied to once-through boiler 10 and a second drain supplied to the boiler with makeup water arranged in makeup water supply line L6 and accommodated in open tank 22 A replenishing water pump 69 for feeding liquid via the line L3 and a control unit 100 for controlling the drain supply valve 81 and the drain pump 64 based on the drain flow rate detected by the drain flow meter 80 are provided.
Thereby, the boiler system 1 can suppress generation | occurrence | production of the malfunction which arises when the amount of drain supplied to the once-through boiler 10 runs short. Specifically, the boiler system 1 can suppress the occurrence of problems due to a drop in the water level in the once-through boiler 10. For example, the boiler system 1 can suppress the breakage of the once-through boiler due to overheating in a state where the water level in the once-through boiler 10 is lowered.
Moreover, since the boiler system 1 is a closed type boiler system, it is excellent in thermal efficiency. Since the boiler system 1 does not supply makeup water to the drain tank 21 but directly supplies makeup water to the second drain supply line L3, the boiler system 1 is excellent in thermal efficiency as a whole.

Further, in the boiler system 1 according to the present embodiment, the control unit 100 determines that the drain flow rate detected by the drain flow meter 80 is predetermined in the liquid supply state in which the drain supply valve 81 and the drain pump 64 are supplying drain. If it is less than the flow rate threshold value, the makeup water pump 69 is controlled so as to start feeding makeup water.
Thereby, since the boiler system 1 is configured to supply makeup water when the flow rate of the drain decreases, it is possible to suitably suppress a shortage of the amount of drain supplied to the once-through boiler 10, Since excessive makeup water is not supplied, it is possible to suppress a decrease in thermal efficiency. The boiler system 1 can suppress the breakage of the once-through boiler due to overheating in a state where the water level in the once-through boiler 10 is lowered, and is excellent in thermal efficiency.

Moreover, the boiler system 1 in the present embodiment further includes a water level detection unit 19 that detects the water level in the once-through boiler 10. In the boiler system 1, the control unit 100 controls the drain supply valve 81 and the drain pump 64 to change the state to the liquid feeding state or the non-liquid feeding state based on the water level detected by the water level detection unit 19.
Thereby, the boiler system 1 can suppress further more suitably that the amount of drain supplied to the once-through boiler 10 is insufficient.
Moreover, since the boiler system 1 can suppress suitably the fall of the water level in the once-through boiler 10, since it is not necessary to set a predetermined water level to an excessively high position (for safety), the dryness of the produced | generated steam is suitable. Can be kept in.

As mentioned above, although one preferable embodiment of the boiler system 1 of this invention was described, this invention is not restrict | limited to embodiment mentioned above and can change suitably.
For example, in the boiler system 1 of the present embodiment, the open tank 22 and the plurality of once-through boilers 10 are connected via the second drain supply line L3, but are not limited thereto, and are directly connected to each other. Also good. In this case, the makeup water stored in the open tank 22 is directly supplied to the once-through boiler 10.

  Further, in the boiler system 1 of the present embodiment, the drain supply valve 81 may be configured such that the degree of opening can be adjusted (the amount of supplied drain can be adjusted). Then, the degree of opening of the drain supply valve 81 may be adjusted and controlled by the control unit 100.

  Further, in the boiler system 1 of the present embodiment, the control unit 100 controls the makeup water pump 69 so as to be turned off after a lapse of a predetermined time, but is not limited thereto, and continuously detects the drain flow rate. Then, control may be performed so that the drain is turned off when the flow rate of the drain becomes equal to or higher than a predetermined flow rate threshold value.

  In the boiler system 1 of the present embodiment, the supply amount (flow rate) of the makeup water by the makeup water pump 69 is not particularly limited, but may be constant, and the drain flow rate measured by the drain flow meter 80 The supply amount may be adjusted based on this. For example, the control unit 100 may control the makeup water pump 69 to supply the same amount (flow rate) of makeup water as the insufficient drain amount (flow rate) based on the information regarding the flow rate from the drain flow meter 80. .

  Moreover, in the boiler system 1 of this embodiment, although the water supply to the once-through boiler 10 was performed by the intermittent water supply which changes a state to a liquid supply state or a non-liquid supply state, it is not restricted to this. That is, water supply to the once-through boiler may be performed continuously.

  Moreover, the boiler system 1 of this embodiment may have an economizer as needed. In this case, since the boiler system 1 can continuously supply a certain amount of drain or the like, boiling or the like in the economizer can be suitably suppressed.

  Moreover, although the boiler system 1 of this embodiment is comprised by the single once-through boiler 10, it is not restricted to this. That is, the boiler system may include a plurality of once-through boilers. In this case, the water level can be suitably controlled by controlling on / off of the makeup water pump that supplies makeup water to each once-through boiler based on the flow rate of the drain supplied to each once-through boiler.

DESCRIPTION OF SYMBOLS 1 Boiler system 10 Through-flow boiler 19 Water level detection part 20 Drain collection apparatus 21 Drain tank 64 Drain pump 69 Makeup water supply pump 80 Drain flow meter 81 Drain supply valve 100 Control part L3 2nd drain supply line L6 Makeup water supply line

Claims (3)

A boiler having a can that generates steam and supplying the generated steam to a load device;
A drain tank that collects the drain generated by condensation of the load device using steam without opening it to the atmosphere;
A drain type supply line that connects the drain tank and the boiler and feeds the drain contained in the drain tank to the boiler, and a closed type boiler system,
A drain liquid feeding unit that is disposed in the drain supply line and feeds the drain accommodated in the drain tank to the boiler;
A drain flow rate detector that is disposed in the drain supply line and detects the flow rate of the drain supplied to the boiler;
A makeup water tank for storing makeup water,
Connect the makeup water tank and the boiler, or connect the makeup water tank and the drain supply line, and supply makeup water stored in the makeup water tank directly to the boiler or via the drain supply line. Make-up water supply line
A replenishment water supply section that is disposed in the replenishment water supply line and that supplies replenishment water stored in the replenishment water tank directly to the boiler or via the drain supply line;
A control unit that controls the makeup water feeding unit based on the flow rate of the drain detected by the drain flow rate detection unit,
The replenishing water feeding section is a boiler system configured to be able to change between an on state and a off state for feeding makeup water . The controller is
In the liquid feeding state in which the drain liquid feeding unit is feeding drain, when the drain flow rate detected by the drain flow rate detecting unit is less than a predetermined flow rate threshold, the replenishment water feeding is started. The boiler system according to claim 1, wherein the boiler water supply unit is controlled. A water level detector for detecting the water level in the boiler;
The controller is
3. The boiler system according to claim 2, wherein the drain liquid feeding unit is controlled to change the state to the liquid feeding state or the non-liquid feeding state in which the drain is not fed based on the water level detected by the water level detecting unit.

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