JP6256153B2 - Boiler system - Google Patents

Description

  The present invention relates to a boiler system. More 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 a load device, and the drain generated by condensation of the steam used as a heat source in the load device is transferred to a drain recovery device having a sealed drain tank having pressure resistance. A closed type boiler system that collects in a high-pressure state and supplies water to the boiler again has been proposed (see, for example, Patent Document 1).

JP 2006-105442 A

  By the way, conventionally, a drain storage tank for storing drain, a pressurized gas introduction line for introducing pressurized gas into the drain storage tank, and a pressurized gas introduction when the water level of the drain stored in the drain storage tank rises. There has been proposed a drain recovery device including a pressure line opening / closing valve that opens the line and closes the pressurized gas introduction line when the water level of the drain stored in the drain storage tank decreases.

  In the above drain recovery device, when the water level of the drain storage tank rises, the pressurized gas is introduced into the drain storage tank from the pressurized gas introduction line. Then, the pressure inside the drain storage tank rises, and when the pressure inside the drain storage tank becomes higher than the pressure of the drain supply destination (for example, boiler), the drain is supplied to the supply destination. Further, when the water level of the drain storage tank is lowered, the introduction of the pressurized gas from the pressurized gas introduction line is stopped. Then, the pressure inside the drain storage tank decreases, and when the pressure inside the drain storage tank becomes equal to or lower than the pressure of the drain supply destination, the supply of the drain to the supply destination is stopped.

  According to such a drain recovery apparatus, a boiler system can be configured without using a drain pump that feeds high-temperature and high-pressure drains to the boiler. However, in this drain recovery device, drain is intermittently supplied to the boiler. When the boiler system is configured to include a drain recovery device that intermittently supplies drain, it is necessary to supply water to the boiler from another water source when drain is not supplied from the drain recovery device. In order to operate the system, it is necessary to appropriately switch the water supply to the boiler.

  Accordingly, an object of the present invention is to provide a closed-type boiler system that can be stably operated when configured to include a drain recovery device that intermittently supplies drain.

  The present invention relates to a boiler that generates steam and supplies it to load equipment, a drain recovery device that recovers the drain generated by condensation of the load equipment using steam without opening it to the atmosphere, and the drain recovery A drain supply line that connects the boiler to the boiler and supplies the drain contained in the drain recovery device to the boiler, a new water supply line that supplies fresh water to the boiler, and the drain supply line or the fresh water A closed-type boiler system comprising: a control unit that controls supply of drain or fresh water from a supply line to the boiler, wherein the drain recovery device includes a drain storage tank that stores drain, and the drain storage tank The pressurized gas introduction line for introducing the pressurized gas into the drainage tank, and the pressurized gas when the water level of the drain accommodated in the drain accommodation tank rises. A pressure line opening / closing valve for closing the pressurized gas introduction line when the water level of the drain accommodated in the drain accommodating tank is lowered, and a pressure for detecting the pressure inside the drain accommodating tank. A detector, and when the pressure detected by the pressure detector is equal to or higher than a first threshold, the controller supplies drain to the boiler from the drain supply line, and When the pressure detected by the pressure detection unit in a state where the drain is supplied to the boiler becomes equal to or lower than the second threshold value equal to or lower than the first threshold value, the supply of the drain from the drain supply line to the boiler is stopped. And a boiler system for supplying new water to the boiler from the new water supply line.

  The boiler system further includes a flow rate measurement unit and a flow rate adjustment valve disposed in the drain supply line, and a fresh water supply pump disposed in the fresh water supply line, and the control unit includes the drain supply. When supplying the drain from the line to the boiler, the amount of the drain supplied to the boiler is controlled by adjusting the opening of the flow rate adjusting valve based on the flow rate of the drain measured by the flow rate measuring unit, When supplying fresh water from the fresh water supply line to the boiler, it is preferable to control the amount of fresh water supplied to the boiler by adjusting the drive amount of the fresh water supply pump.

  The drain recovery device further includes a pressure detection line that connects the drain storage tank and the pressure detection unit, and a detection line on / off valve that opens and closes the pressure detection line, and the pressure detection unit includes: A pressure switch that is turned on when the pressure inside the drain storage tank becomes equal to or higher than the first threshold, and that is turned off when the pressure inside the drain storage tank becomes equal to or lower than the second threshold; The control unit preferably closes the detection line on / off valve for a first preset time when the pressure switch is turned from ON to OFF.

  Moreover, it is preferable that the boiler system 1 is further provided with the feed water heater which performs heat exchange between the water supplied to the said boiler, and the combustion gas discharged | emitted from the said boiler.

  According to the boiler system of the present invention, the boiler system can be stably operated even when the boiler system is configured to include a drain recovery device that intermittently supplies drain.

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 a boiler body.

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. 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 boiler body.

As shown in FIG. 1, the boiler system 1 of the present embodiment controls the operation of a boiler device 70 including a boiler 10, a closed-type drain recovery device 20, an open tank 30, and the boiler system 1. And a control unit 100.
In addition, the boiler system 1 includes a plurality of lines that connect these devices and through which steam or water flows, a plurality of valves that open and close the plurality of lines, and a plurality of pumps that are arranged in a predetermined line. Specifically, the boiler system 1 includes a steam supply line L1, a drain recovery line L2, a drain supply line L3, an overflow line L4, and a fresh water supply line L5 as lines.

  As shown in FIG. 1, the boiler device 70 includes a boiler 10, a feed water heater 40, a steam header 71 that collects steam generated by the boiler 10, and a connecting pipe 72 that connects the boiler 10 and the steam header 71. And comprising.

The boiler 10 generates steam by heating the feed water supplied to the inside with combustion gas, and supplies the generated steam to a load device 50 described later.
In the present embodiment, the boiler 10 (a plurality of water pipes) is supplied with the drain recovered by the drain recovery device 20 as feed water. Specifically, the boiler 10 (a plurality of water pipes) is supplied with drain water stored in a drain storage tank 21 described later or fresh water stored in the open tank 30 as supply water (hereinafter, supplied as supply water). Drain or fresh water is also called drain etc.).

  As shown in FIG. 2, the boiler 10 includes a can 11, a plurality of water pipes 12, a lower header 14, an upper header 15, a duct 16, a burner 17, and an exhaust pipe 18.

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.

  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 or the like is supplied to the lower header 14, and the drain or the like 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 161 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 161 and the combustion air supplied from the blower and supplies the mixed gas toward the inside of the can 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.

  The feed water heater 40 is provided in the exhaust pipe 18. The feed water heater 40 performs heat exchange between the combustion gas discharged from the can body 11 and a drain or the like supplied to the can body 11 from a drain supply line L3 or a fresh water supply line L5 described later.

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

The drain recovery device 20 recovers the drain produced by agglomeration of the steam generated by the boiler 10 in the load device 50 in a high temperature and high pressure state, and supplies the recovered drain to the boiler 10 again as feed water. To do. Details of the drain recovery device 20 will be described later.
The open tank 30 is open to the atmosphere. The open tank 30 stores fresh water supplied to the boiler 10. Further, the drain discharged from an overflow line L4 described later is supplied to the open tank 30.

The steam supply line L <b> 1 connects the steam header 71 and the load device 50 and supplies the steam generated by the boiler 10 to the load device 50.
The drain recovery line L <b> 2 connects the load device 50 and the drain recovery device 20, and supplies the drain generated in the load device 50 to the drain recovery device 20. In the drain recovery line L2, a steam trap 61 and a check valve 62 that discharge drain generated in the load device 50 and prevent discharge of steam are disposed.

  The drain supply line L <b> 3 connects the drain recovery device 20 and the boiler 10, and supplies the drain accommodated in the drain recovery device 20 to the boiler 10. In the drain supply line L3, check valves 31, 32, 33, a shutoff valve 34, a flow rate adjusting valve 35, and a flow meter 36 as a flow rate measuring unit are arranged. The check valve 31 is disposed on the upstream side of the drain supply line L3, and prevents the backflow of drain from the drain supply line L3 to the drain recovery device 20. The check valves 32 and 33 are arranged on the downstream side of the drain supply line L3, and prevent the backflow of drain from the boiler 10 to the drain supply line L3.

The shut-off valve 34 and the flow rate adjustment valve 35 are constituted by motor valves. The shutoff valve 34 operates when an abnormality occurs in the boiler system 1 and shuts off the flow path of the drain supply line L3. The flow rate adjusting valve 35 adjusts the flow rate of the drain flowing through the drain supply line L3 by adjusting the opening degree.
The flow meter 36 measures the flow rate of the drain flowing through the drain supply line L3.

  The overflow line L4 connects the drain recovery line L2 and the open tank 30. The overflow line L4 causes the drain that is not accommodated in the drain recovery device 20 out of the drain flowing through the drain recovery line L2 to overflow to the open tank 30 side. A check valve 41 is disposed in the overflow line L4.

  The fresh water supply line L5 connects the open tank 30 and the drain supply line L3, and supplies the water stored in the open tank 30 to the boiler 10 via the drain supply line L3. In the present embodiment, the downstream side of the fresh water supply line L5 is connected between the check valve 32 and the check valve 33 in the drain supply line L3. A fresh water supply pump 51 and a check valve 52 are disposed in the fresh water supply line L5. The fresh water supply pump 51 includes an impeller, a motor that rotationally drives the impeller, and an inverter (none of which is shown) that drives the motor. And this new water supply pump 51 is driven at the rotational speed according to the frequency of the drive electric power supplied from the inverter. The check valve 52 prevents the backflow of drain from the drain supply line L3 to the fresh water supply line L5.

Next, the drain collection device 20 will be described. In the present embodiment, the drain recovery device 20 includes a drain storage tank, a pressurized gas introduction line 22, a pressure line opening / closing valve 23, a pressure switch 24 as a pressure detection unit, a pressure detection line 25, and a detection line. An on-off valve 26.
The drain storage tank 21 recovers and stores the drain that flows through the drain recovery line L2.
The pressurized gas introduction line 22 connects a pressurized gas supply source (not shown) and the drain storage tank 21, and introduces the pressurized gas into the drain storage tank 21. As the pressurized gas stored in the drain storage tank 21, air or steam is used.

  The pressurization line opening / closing valve 23 is disposed inside the drain storage tank 21 and opens and closes the flow path of the pressurized gas introduction line 22 according to the water level of the drain storage tank 21. Specifically, the pressurization line opening / closing valve 23 opens the pressurization gas introduction line when the water level of the drain stored in the drain storage tank 21 rises, and the water level of the drain stored in the drain storage tank 21 is reduced. When the pressure drops, the pressurized gas introduction line is closed. The pressurization line on-off valve 23 includes an on-off valve disposed on the distal end side of the pressurized gas introduction line 22, a float, and a connecting arm that connects the float and the on-off valve (both shown in the figure). Not shown).

  The pressure switch 24 detects the pressure inside the drain storage tank 21. In the present embodiment, the pressure switch 24 is turned on when the pressure inside the drain storage tank 21 becomes a first threshold value (for example, 0.7 MPa) or more. Further, the pressure is set to be OFF when the pressure inside the drain storage tank 21 is equal to or lower than a second threshold value (for example, 0.6 MPa) which is a value equal to or lower than the first threshold value. As the first threshold value, a value higher than the pressure of the can 11 of the boiler 10 at the time of combustion is set.

The pressure detection line 25 connects the drain storage tank 21 and the pressure switch 24. That is, in this embodiment, the pressure switch 24 detects the pressure inside the drain storage tank 21 via the pressure detection line 25.
The detection line opening / closing valve 26 is disposed in the pressure detection line 25 and opens and closes the flow path of the pressure detection line 25. In the present embodiment, the detection line opening / closing valve 26 is configured by an electromagnetic valve.

According to the drain recovery device 20 described above, when the water level of the drain storage tank 21 rises, the pressurization line opening / closing valve 23 is opened, and the pressurized gas is introduced into the drain storage tank 21 from the pressurized gas introduction line 22. The Then, the pressure inside the drain storage tank 21 increases, and when the pressure inside the drain storage tank 21 becomes higher than the pressure in the drain supply line L3 (boiler 10), the drain is led to the drain supply line L3, and the boiler 10 is supplied. Further, when the water level of the drain storage tank 21 is lowered, the pressurization line opening / closing valve 23 is closed, and the introduction of the pressurized gas from the pressurized gas introduction line 22 is stopped. Then, the pressure inside the drain storage tank 21 decreases, and when the pressure inside the drain storage tank 21 becomes equal to or lower than the pressure of the boiler 10, the supply of drain to the boiler 10 is stopped.
Further, in the above operation, when the pressure inside the drain storage tank 21 exceeds the first threshold value, the pressure switch 24 is turned ON, and when the pressure switch 24 is lower than the second threshold value, the pressure switch 24 is It becomes OFF.

  The control unit 100 controls the operation of the boiler system 1. The control unit 100 causes the boiler 10 to supply drain or fresh water from the drain supply line L3 or the fresh water supply line L5 in response to a water supply request from the boiler 10. In the present embodiment, the boiler system 1 performs continuous water supply control for supplying water at a predetermined flow rate (minimum flow rate) even when there is no water supply request from the boiler 10.

In the present embodiment, the control unit 100 determines whether or not drain supply from the drain recovery device 20 to the boiler 10 is possible based on the operation of the pressure switch 24, and determines which line to supply water from. To do.
That is, when the pressure inside the drain storage tank 21 becomes higher than the pressure inside the can 11 of the boiler 10, the drain can be supplied from the drain storage tank 21 to the boiler 10. Therefore, the control unit 100 causes the boiler 10 to supply drain from the drain supply line L3 when the pressure switch 24 is turned ON because the pressure inside the drain storage tank 21 becomes equal to or higher than the first threshold value.

  In this case, the control unit 100 controls the amount of drain supplied to the boiler 10 by adjusting the opening of the flow rate adjustment valve 35 based on the flow rate of the drain measured by the flow meter 36. Moreover, the control part 100 stops the fresh water supply pump 51, and stops supply of the fresh water from the fresh water supply line L5 to the boiler 10. FIG.

  Further, when the pressure inside the drain storage tank 21 becomes equal to or lower than the pressure inside the can 11 of the boiler 10, the drain cannot be supplied from the drain storage tank 21 to the boiler 10. Therefore, when the pressure inside the drain storage tank 21 falls below the second threshold value and the pressure switch 24 is turned OFF, the control unit 100 stops the supply of drain from the drain supply line L3 to the boiler 10 and performs a new operation. Fresh water is supplied to the boiler 10 from the water supply line L5.

  In this case, the control unit 100 controls the frequency of the drive power supplied from the inverter to the motor to adjust the rotation speed of the fresh water supply pump 51, thereby controlling the amount of fresh water supplied to the boiler 10. Moreover, the control part 100 stops the supply of the drain from the drain supply line L3 to the boiler 10 by making the cutoff valve 34 and the flow regulating valve 35 into a fully closed state.

  In the present embodiment, the pressure switch 24 and the flow rate adjustment valve 35 are prevented from prematurely deteriorating due to frequent ON-OFF of the drain supply from the drain supply line L3 to the boiler 10. As a configuration, the control unit 100 includes a valve control unit 110.

When the pressure switch 24 changes from ON to OFF, the valve control unit 110 closes the detection line opening / closing valve 26 for a first time (for example, 5 minutes) set in advance.
Thereby, it is possible to prevent the start and stop of the supply of drain from the drain recovery device 20 to the boiler 10 from being repeated frequently.

  According to the boiler system 1 of this embodiment demonstrated above, there exist the following effects.

  (1) The drain recovery device 20 is connected to a drain storage tank 21, a pressurized gas introduction line 22 for introducing pressurized gas into the drain storage tank 21, and a pressurized gas introduction when the water level of the drain storage tank 21 rises. A pressure line opening / closing valve 23 for opening the line 22 and closing the pressurized gas introduction line 22 when the water level of the drain storage tank 21 is lowered; a pressure switch 24 for detecting the pressure inside the drain storage tank 21; When the pressure detected by the pressure switch 24 is equal to or higher than the first threshold value, the control unit 100 supplies the drain to the boiler 10 from the drain supply line L3, and supplies the boiler 10 to the boiler 10 from the drain supply line L3. When the pressure detected by the pressure switch 24 is less than or equal to the second threshold value while the drain is being supplied, the drain supply line L3 By stopping the supply of the drain to Ira 10, from fresh water supply line L5 is supplied Shinmizu to the boiler 10. Thus, when the closed boiler system 1 is configured including the drain recovery device 20 that intermittently supplies drain to the boiler 10, the boiler from the drain recovery device 20 is based on the pressure detected by the pressure switch 24. 10 can determine whether or not to supply the drain to 10. Therefore, when drain can be supplied from the drain recovery device 20, drain can be supplied from the drain recovery device 20 to the boiler 10, and in other cases, fresh water is supplied to the boiler 10 from the new water supply line L5. Therefore, the boiler system 1 including the drain recovery device 20 that intermittently supplies the drain to the boiler 10 can be stably operated.

  (2) The boiler system 1 includes a flow meter 36 and a flow rate adjustment valve 35 disposed in the drain supply line L3, and a fresh water supply pump 51 disposed in the fresh water supply line L5, and a control unit 100, when supplying the drain to the boiler 10 from the drain supply line L3, the amount of the drain supplied to the boiler 10 by adjusting the opening of the flow rate adjusting valve 35 based on the flow rate of the drain measured by the flow meter 36. When the new water is supplied to the boiler 10 from the new water supply line L5, the amount of the new water supplied to the boiler 10 is controlled by adjusting the rotation speed of the new water supply pump. Thus, when supplying high-temperature and high-pressure drain to the boiler 10, the supply amount of the drain can be adjusted without using a pump, and when supplying fresh water at normal pressure, the rotation speed of the new water supply pump 51 The amount of fresh water supplied can be adjusted. Therefore, the boiler system 1 can be operated more efficiently.

  (3) The drain recovery device 20 includes a pressure detection line 25 that connects the drain storage tank 21 and the pressure switch 24, and a detection line on / off valve 26 that opens and closes the pressure detection line 25, and a control unit. 100 includes a valve control unit 110 that closes the first time detection line opening / closing valve 26 when the pressure switch 24 is turned from ON to OFF. As a result, once the drain is supplied from the drain recovery device 20 to the boiler 10, the first time pressure detection line 25 is closed to close the first time pressure detection line 25 to the boiler 10. The drain supply is stopped. Therefore, excessive operation of the pressure switch 24 and the flow rate adjusting valve 35 can be prevented, so that the life of these members can be extended.

  (4) The boiler device 70 is configured to include the can 11 and the feed water heater 40. Thereby, the efficiency of the boiler system 1 can be improved more.

As mentioned above, although one preferable embodiment of the boiler system 1 of this invention was described, this invention is not restrict | limited to the above-mentioned embodiment, It can change suitably.
For example, in the present embodiment, the pressure detection unit is configured by the pressure switch 24, but is not limited thereto. That is, the pressure detection unit may be configured by a pressure sensor.

  Moreover, in this embodiment, although this invention was applied to the boiler system 1 which performs continuous water supply control, it is not restricted to this. That is, the present invention may be applied to a boiler system for intermittent water supply control that does not perform water supply when there is no water supply request from the boiler.

DESCRIPTION OF SYMBOLS 1 Boiler system 10 Boiler 11 Can body 20 Drain collection | recovery apparatus 21 Drain storage tank 22 Pressurized gas introduction line 23 Pressurization line on-off valve 24 Pressure switch (pressure detection part)
25 Pressure detection line 26 Detection line open / close valve 35 Flow rate adjustment valve 36 Flow meter (flow rate measurement unit)
40 Water heater 50 Load device 100 Control unit L3 Drain supply line L5 New water supply line

Claims (4)

A boiler that generates steam and supplies it to load equipment;
A drain recovery device that recovers the drain generated by the condensation of the load equipment by using steam without opening it to the atmosphere;
A drain supply line that connects the drain recovery device and the boiler and supplies the drain stored in the drain recovery device to the boiler;
A new water supply line for supplying new water to the boiler;
A controller for controlling the supply of drain or fresh water from the drain supply line or the fresh water supply line to the boiler, and a closed type boiler system comprising:
The drain recovery device is
A drain storage tank for storing the drain;
A pressurized gas introduction line for introducing pressurized gas into the drain storage tank;
The pressurized gas introduction line is opened when the water level of the drain stored in the drain storage tank rises, and the pressurized gas introduction line is closed when the water level of the drain stored in the drain storage tank decreases. A pressure line opening / closing valve to
A pressure detector for detecting the pressure inside the drain storage tank,
The controller is
When the pressure detected by the pressure detection unit is equal to or higher than a first threshold, the drain is supplied from the drain supply line to the boiler,
When the pressure detected by the pressure detection unit in a state where the drain is supplied from the drain supply line to the boiler is equal to or lower than the second threshold value equal to or lower than the first threshold value, the drain supply line is supplied to the boiler. A boiler system that stops draining and supplies new water to the boiler from the new water supply line. A flow rate measurement unit and a flow rate adjustment valve disposed in the drain supply line;
A new water supply pump disposed in the new water supply line,
The controller is
When supplying drain to the boiler from the drain supply line, the amount of drain supplied to the boiler is controlled by adjusting the opening of the flow rate adjusting valve based on the drain flow rate measured by the flow rate measuring unit. And
The boiler system according to claim 1, wherein when new water is supplied from the new water supply line to the boiler, the amount of new water supplied to the boiler is controlled by adjusting a driving amount of the new water supply pump. The drain recovery device is
A pressure detection line connecting the drain storage tank and the pressure detection unit;
A detection line on / off valve that opens and closes the pressure detection line,
The pressure detection unit is turned on when the pressure inside the drain storage tank becomes equal to or higher than the first threshold, and turned off when the pressure inside the drain storage tank becomes equal to or lower than the second threshold. Consists of pressure switches,
The controller is
3. The boiler system according to claim 1, wherein when the pressure switch is turned from ON to OFF, the detection line opening / closing valve is closed for a preset first time.   The boiler system in any one of Claims 1-3 further equipped with the feed water heater which performs heat exchange between the water supplied to the said boiler, and the combustion gas discharged | emitted from the said boiler.

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