JP2016161259A - Boiler system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boiler system capable of suppressing frequent switching of a flow passage in a drain relief line, and capable of being stably operated.SOLUTION: A boiler system 1 includes a boiler 10, a drain tank 20, a drain recovery line L2, a drain recovery valve 23 arranged in the drain recovery line L2, an open tank 30, a drain relief line L8 connecting the upstream side of the drain recovery valve 23 in the drain recovery line L2 with the open tank 30, a drain relief valve 81, a water level measuring section 25 for measuring a water level in the drain tank 20, a storage section 120 for storing a target water level and a drain relief water level, a first water level control section 111 for controlling an opening of the drain relief valve 81 so that the water level in the drain tank 20 becomes the target water level, and a second water level control section 112 for closing the drain recovery valve 23 and opening the drain relief valve 81 when the water level in the drain tank 20 exceeds the drain relief water level.SELECTED DRAWING: Figure 1

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 the load equipment, and the drain generated by condensation of the steam used as a heat source in the load equipment is collected in a sealed drain tank with pressure resistance at high temperature and pressure. And the closed type boiler system which supplies water to a boiler again is proposed.

  In such a boiler system, when the amount of drain stored in the drain tank increases, a drain release line is provided for draining the drainage generated in the load device to the open tank side that is released to the atmosphere without being collected in the drain tank. . The flow path of the drain escape line is closed when the drain is collected in the drain tank, and is opened when the water level of the drain tank exceeds a predetermined threshold (see, for example, Patent Document 1).

JP 2013-204961 A

  By the way, the amount of the drain recovered in the drain tank varies greatly due to a load variation or the like. In particular, if the boiler system is configured to include a plurality of boilers, the amount of drain generated increases, and therefore, the drain escape line may frequently be switched. If the flow path of the drain relief line frequently occurs, the life of the valve that switches the flow path is shortened. In addition, since vibration is generated in the pipes constituting the drain escape line as the flow path is switched, frequent flow path switching is not preferable for stable operation of the boiler system.

  Therefore, an object of this invention is to provide the boiler system which can suppress the switching of the frequent flow path in a drain escape line, and can be operated stably.

  The present invention provides a boiler that generates steam and supplies it to load equipment, a drain tank that collects the drain generated by condensation of the load equipment using steam without opening it to the atmosphere, and the load equipment. A drain recovery line that connects the drain tank, a drain recovery valve that is disposed in the drain recovery line, a drain that connects the drain tank and the boiler, and supplies the drain accommodated in the drain tank to the boiler A supply line; an open tank that is open to the atmosphere and stores makeup water to be supplied to the boiler; a drain relief line that connects the upstream side of the drain recovery valve in the drain recovery line and the open tank; and the drain relief line. A drain relief valve, a water level measuring unit for measuring the water level of the drain tank, and the drain tongue. A storage unit that stores a target water level in the tank, a drain relief water level that is higher than the target water level, and a first water level control unit that controls the opening of the drain relief valve so that the water level of the drain tank becomes the target water level; And a second water level controller that closes the drain recovery valve and opens the drain relief valve when the water level of the drain tank exceeds the drain relief water level.

  The drain relief valve includes a first drain relief valve whose opening degree can be adjusted, and a second drain relief valve which can be switched between an open state and a closed state, and the drain relief line includes the first drain relief valve. It is preferable to include a first drain relief line in which a relief valve is arranged and a second drain relief line in which the second drain relief valve is arranged.

  Further, the boiler system includes a first makeup water line connecting the open tank and the drain tank, a first makeup water pump disposed in the first makeup water line, and a water level of the drain tank in which the drain escape is performed. A system stop control unit for stopping the boiler system when an alarm water level higher than the water level is exceeded, and a first make-up water pump when the water level in the drain tank falls below a make-up water supply water level lower than the target water level. It is preferable to further include a makeup water control unit to be driven.

  According to the boiler system of the present invention, frequent switching of the flow path in the drain escape line can be suppressed, and the operation can be stably performed.

It is a figure showing the composition of the boiler system concerning one embodiment of the present invention. It is a functional block diagram which shows the structure of a control apparatus.

Hereinafter, a preferred embodiment of a boiler system of the present invention will be described with reference to the drawings.
The boiler system 1 of this embodiment is provided with the boiler apparatus 10, the drain tank 20, the open tank 30, and the control apparatus 100 as shown in FIG. Moreover, the boiler system 1 is provided with several lines which connect these apparatuses and a vapor | steam or water distribute | circulates. Specifically, the boiler system 1 includes a first steam supply line L1, a drain recovery line L2, a drain supply line L3, a second steam supply line L4, a flash steam line L5, and a first supply as lines. A water line L6, a drain return line L7, a drain escape line L8, and a second makeup water line L9 are provided.

  As shown in FIG. 1, the boiler device 10 connects a plurality of once-through boilers 11, a steam header 12 where steam generated by the plurality of once-through boilers 11 is gathered, and the once-through boiler 11 and the steam header 12. And a connecting pipe 13.

  The once-through boiler 11 generates steam by heating the feed water supplied to the inside with combustion gas. In the present embodiment, the once-through boiler 11 is supplied with drain collected in a drain tank 20 described later as feed water.

As shown in FIG. 1, the steam generated in the once-through boiler 11 is supplied to the steam header 12 through a connecting pipe 13. The steam header 12 stores the steam generated by the once-through boiler 11 and supplies it to the load device 40.
The load device 40 uses the steam generated in the once-through boiler 11 as a heat source, and performs direct heating or indirect heating of the heating target.

  The drain tank 20 is constituted by a pressure vessel having pressure resistance. The drain tank 20 collects the drain generated by condensing the steam generated by the once-through boiler 11 in the load device 40 in a high-temperature and high-pressure state. The drain tank 20 is provided with a water level sensor 25 as a water level measuring unit that detects the water level of the drain collected in the drain tank 20.

  The open tank 30 is open to the atmosphere. The open tank 30 stores makeup water supplied to the once-through boiler 11. In addition, flush steam generated from the drain in the drain tank 20 and drain that flows through a drain escape line L8 described later are introduced into the open tank 30.

The first steam supply line L <b> 1 connects the steam header 12 and the load device 40, and supplies the steam generated by the plurality of once-through boilers 11 to the load device 40.
The drain recovery line L <b> 2 connects the load device 40 and the drain tank 20, and supplies the drain generated in the load device 40 to the drain tank 20. A steam trap 21, a check valve 22, and a drain recovery valve 23 are disposed in the drain recovery line L2.
The steam trap 21 is disposed on the downstream side of the load device 40 in the drain recovery line L2, discharges the drain generated in the load device 40, and prevents the discharge of steam. The check valve 22 is disposed on the downstream side of the steam trap 21 and prevents the drain from flowing back to the load device 40 side in the drain recovery line L2. The drain recovery valve 23 is disposed in the vicinity of the connection portion with the drain tank 20 in the drain recovery line L2. The drain recovery valve 23 is configured by a motor valve. The drain recovery valve 23 operates based on a control signal from the control device 100, and opens and closes the flow path of the drain recovery line L2.

The drain supply line L <b> 3 connects the drain tank 20 and the once-through boiler 11, and supplies the drain collected in the drain tank 20 to the plurality of once-through boilers 11. The upstream end of the drain supply line L3 is connected to the lower part of the drain tank 20. Further, the downstream side of the drain supply line L3 branches so as to be connected to each of the plurality of once-through boilers 11. A drain pump 31 and a drain supply valve 32 are arranged in the drain supply line L3.
The drain pump 31 is disposed upstream of the branch portion in the drain supply line L3, and boosts the drain supplied from the drain tank 20 and sends it to the once-through boiler 11 side. The drain supply valve 32 is configured by a motor valve. The drain supply valve 32 is disposed on the downstream side of the branch portion in the drain supply line L3 so as to correspond to each of the plurality of once-through boilers 11. The opening of the drain supply valve 32 is adjusted by the control device 100, and thereby the amount of drain supplied to the once-through boiler 11 is controlled.

The second steam supply line L4 connects the steam header 12 and the drain tank 20. The second steam supply line L4 supplies the steam generated in the once-through boiler 11 to the drain tank 20 and adjusts the pressure inside the drain tank 20. A pressure regulating valve 41 and a motor valve 42 are disposed in the second steam supply line L4.
The pressure adjustment valve 41 adjusts so that the pressure of the steam flowing through the downstream side of the pressure adjustment valve 41 in the second steam supply line L4 becomes a predetermined pressure. The opening degree of the motor valve 42 is adjusted by the control device 100, whereby the amount of steam supplied to the drain tank 20 is adjusted, and the pressure inside the drain tank 20 is controlled to be a predetermined pressure.

The flash steam line L5 connects the drain tank 20 and the open tank 30, and discharges the flash steam generated in the drain tank 20 to the open tank 30. The upstream side of the flash steam line L <b> 5 is branched into two, and each end is connected to the upper part of the drain tank 20. A pressure regulating valve 51 is disposed at one of the branch portions in the flash steam line L5, and a motor valve 52 is disposed at the other.
When the pressure inside the drain tank 20 exceeds a predetermined pressure, the pressure regulating valve 51 releases the flash steam to the open tank 30 side and reduces the pressure inside the drain tank 20.
The motor valve 52 operates based on a control signal from the control device 100, and opens and closes the flow path of the flash steam line L5. The motor valve 52 is provided as a backup in the case where the pressure regulating valve 51 does not operate.

  The first makeup water line L <b> 6 connects the open tank 30 and the drain tank 20, and supplies water stored in the open tank 30 to the drain tank 20. A first makeup water pump 61 is disposed in the first makeup water line L6.

  The drain return line L7 connects the drain supply line L3 and the drain tank 20. More specifically, the upstream (base end) end of the drain return line L7 is connected between the drain pump 31 and the drain supply valve 32 in the drain supply line L3. The downstream end of the drain return line L7 is branched into a line connected to the upper part of the drain tank 20 and a line connected to the lower part of the drain tank 20. A motor valve 72 is disposed on a line connected to the upper portion of the drain tank 20, and an orifice 71 is disposed on a line connected to the lower portion of the drain tank 20.

  The drain return line L7 returns a part or all of the drain flowing through the drain supply line L3 to the drain tank 20. More specifically, from the line connected to the lower part of the drain tank 20, the drain is circulated to the liquid phase part of the drain tank 20, and from the line connected to the upper part of the drain tank 20, the gas phase of the drain tank 20 is Drain is circulated in the part. In this drain return line L7, the flow rate of the drain circulated to the liquid phase part is adjusted by the orifice 71 to make the temperature of the drain stored in the drain tank 20 uniform, and by the drain circulated to the gas phase part, The flash steam generated inside the drain tank 20 is recovered.

The drain escape line L8 connects the drain recovery line L2 and the open tank 30. The drain escape line L8 allows the drain flowing through the drain recovery line L2 to escape to the open tank 30 when the drain recovered in the drain tank 20 becomes excessive.
In the present embodiment, the upstream side of the drain relief line L8 is branched into two lines, a first drain relief line L81 and a second drain relief line L82, and the respective upstream end portions of the drain relief line L2 are branched. Connected to. That is, in the present embodiment, the first drain relief line L81 and the second drain relief line L82 merge on the downstream side and are connected to the open tank 30 as one line.

A first drain relief valve 81 is disposed in the first drain relief line L81. The first drain relief valve 81 is configured by a motor valve whose opening degree can be adjusted based on a control signal from the control device 100. The first drain relief valve 81 adjusts the flow rate of the drain flowing through the first drain relief line L81 by changing the opening degree.
A second drain relief valve 82 is disposed in the second drain relief line L82. The second drain relief valve 82 is configured by a motor valve or an electromagnetic valve that can be switched between an open state and a closed state based on a control signal from the control device 100. The second drain relief valve 82 opens and closes the flow path of the second drain relief line L82.

  The second makeup water line L9 connects the open tank 30 and the plurality of once-through boilers 11. The second make-up water line L9 supplies water stored in the open tank 30 to the once-through boiler 11 as make-up water. In the present embodiment, the upstream end portion of the second makeup water line L9 is connected to the lower portion of the open tank 30. Further, the downstream side of the second make-up water line L9 branches so as to be connected to each of the plurality of once-through boilers 11.

  A makeup water pump 91 is disposed in the second makeup water line L9. The makeup water pump 91 pressurizes the makeup water supplied from the open tank 30 and supplies it to the once-through boiler 11. The makeup water pumps 91 are arranged on the downstream side of the branch portion in the second makeup water line L9, and a plurality of makeup water pumps 91 are provided corresponding to the plurality of once-through boilers 11.

The control device 100 includes a CPU as the control unit 110 and a memory as the storage unit 120, and controls the boiler system 1 by controlling the opening and closing of various valves and the operation of various pumps.
In the present embodiment, the control device 100 controls the opening and closing of the drain recovery valve 23, the first drain relief valve 81, and the second drain relief valve 82 based on the water level of the drain tank 20 detected by the water level sensor 25.
More specifically, as shown in FIG. 2, the control unit 110 of the present embodiment is configured to control the water level of the drain tank 20 as a first water level control unit 111, a second water level control unit 112, The system stop control unit 113 and the makeup water control unit 114 are provided. The storage unit 120 also stores a target water level in the drain tank 20, a drain relief water level higher than the target water level, an alarm water level higher than the drain relief water level, and a makeup water supply water level lower than the target water level.

  First, when the water level of the drain tank 20 detected by the water level sensor 25 is lower than the target water level, the control unit 110 opens the drain recovery valve 23, and the first drain relief valve 81 and the second drain relief valve 82. Close. Thereby, the drain flowing through the drain recovery line L <b> 2 is recovered in the entire drain tank 20.

  The first water level control unit 111 controls the opening degree of the first drain relief valve 81 so that the water level of the drain tank 20 becomes the target water level. More specifically, the first water level control unit 111 closes the first drain relief valve 81 when the water level of the drain tank 20 detected by the water level sensor 25 is equal to or lower than the target water level. When the water level of the drain tank 20 detected by the water level sensor 25 exceeds the target water level, the opening of the first drain relief valve 81 is adjusted so that the water level of the drain tank 20 becomes the target water level. That is, the first water level control unit 111 increases the opening degree of the first drain relief valve 81 as the water level of the drain tank 20 becomes higher than the target water level, so that the amount of drain circulating to the drain relief line L8 side. And the amount of drain recovered in the drain tank 20 is decreased.

  The second water level control unit 112 closes the drain recovery valve 23 and opens the first drain relief valve 81 and the second drain relief valve 82 when the water level of the drain tank 20 exceeds the drain relief water level. More specifically, the 2nd water level control part 112 opened the 1st drain relief valve 81 by the 1st water level control part 111, and escaped some drains which distribute | circulate the drain collection line L2 to the open tank 30 side. Even in the state, when the water level of the drain tank 20 further rises and exceeds the drain relief water level, the drain recovery valve 23 is closed to stop the inflow of drain into the drain tank 20, and the first drain relief valve 81 and The second drain relief valve 82 is opened. Thereby, the drain which distribute | circulates the drain collection line L2 is introduce | transduced into the open tank 30 via the drain drain line L8.

  Accordingly, in the present embodiment, the first water level control unit 111 controls the opening degree of the first drain relief valve 81 so that the water level of the drain tank 20 becomes the target water level, and a drastic increase in the inflow amount of drain, etc. Thus, when the water level of the drain tank 20 exceeds the drain escape water level, the water level of the drain tank 20 can be lowered by switching the drain flow path. Therefore, frequent switching of the flow path in the drain escape line L8 can be suppressed, and the boiler system 1 can be operated stably.

  The system stop control unit 113 stops the boiler system 1 when the water level of the drain tank 20 exceeds the warning water level higher than the drain escape water level. That is, the system stop control unit 113 stops the boiler system 1 when the water level of the drain tank 20 further rises and exceeds the warning water level even when the drain recovery valve 23 is closed by the second water level control unit 112. This prevents the operation from being continued in a state where an abnormality has occurred in the water level of the drain tank 20.

  The makeup water control unit 114 drives the first makeup water pump 61 when the water level of the drain tank 20 falls below the makeup water supply water level lower than the target water level.

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

  (1) The boiler system 1 includes a first water level control unit 111 that controls the opening degree of the first drain relief valve 81 so that the water level of the drain tank 20 becomes the target water level, and the water level of the drain tank 20 sets the drain relief water level. And a second water level control unit 112 that closes the drain recovery valve 23 and opens the first drain relief valve 81 and the second drain relief valve 82 when exceeding. Thereby, the first water level control unit 111 controls the opening of the first drain relief valve 81 so that the water level of the drain tank 20 becomes the target water level, and the drain tank 20 When the water level exceeds the drain escape water level, the drain flow path can be switched to lower the water level of the drain tank 20. Therefore, frequent switching of the flow path in the drain escape line L8 can be suppressed, and the boiler system 1 can be operated stably.

  (2) The drain relief valve includes a first drain relief valve 81 whose opening degree can be adjusted, and a second drain relief valve 82 that can be switched between an open state and a closed state, and a drain relief line L8 is provided. The first drain relief line L81 in which the first drain relief valve 81 is arranged and the second drain relief line L82 in which the second drain relief valve 82 is arranged are configured. Thereby, the second drain relief valve 82 is opened when the water level of the drain tank 20 exceeds the drain relief water level while adjusting the water level of the drain tank 20 by controlling the opening degree of the first drain relief valve 81. Thus, the drain is introduced into the open tank 30 from the two lines of the first drain relief line L81 and the second drain relief line L82. Further, since the opening control and the opening / closing control are performed by separate drain relief valves, the life of the drain relief valve can be extended.

  (3) The system stop control unit 113 for stopping the boiler system 1 when the water level of the drain tank 20 exceeds the alarm water level higher than the drain escape water level, and the water level of the drain tank 20 is lower than the target water level. And a makeup water control unit 114 that drives the first makeup water pump 61 when it falls below a low makeup water supply water level. Thereby, the safety | security of the boiler system 1 can be improved more. Moreover, since the excessive raise of the water level of the drain tank 20 can be suppressed suitably by control of the 1st water level control part 111 and the 2nd water level control part 112, the frequency which operates the system stop control part 113 can be reduced. Therefore, the boiler system 1 can be operated more stably without impairing the safety of the boiler system 1.

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 this embodiment, although the boiler system 1 was comprised by the three once-through boilers 11, it is not restricted to this. That is, the boiler system may be configured to include one or two once-through boilers, or may be configured to include four or more once-through boilers.

  In the present embodiment, the drain relief line L8 includes a first drain relief line L81 in which the first drain relief valve 81 is arranged and a second drain relief line L82 in which the second drain relief valve 82 is arranged. However, it is not limited to this. That is, the drain relief line may be constituted by a single line having one drain relief valve.

  In the present embodiment, the first drain relief valve 81 and the second drain relief valve 82 are controlled by the second water level control unit 112, but the present invention is not limited to this. That is, you may make a 2nd water level control part control only a 2nd drain relief valve.

  In this embodiment, a motor valve is used as a valve. However, the present invention is not limited to this, and the type of valve may be changed as appropriate.

1 Boiler system 10 Boiler equipment (Boiler)
20 Drain tank 23 Drain recovery valve 25 Water level sensor (water level measuring unit)
DESCRIPTION OF SYMBOLS 30 Open tank 40 Load apparatus 61 1st makeup water pump 81 1st drain relief valve 82 2nd drain relief valve 111 1st water level control part 112 2nd water level control part 113 System stop control part 114 Makeup water control part 120 Storage part L2 Drain recovery line L3 Drain supply line L6 First make-up water line L8 Drain relief line L81 First drain relief line L82 Second drain relief line

Claims (3)

A boiler that generates steam and supplies it to load equipment;
A drain tank that collects the drain generated by condensation of the load device using steam without opening it to the atmosphere;
A drain recovery line connecting the load device and the drain tank;
A drain recovery valve disposed in the drain recovery line;
A drain supply line for connecting the drain tank and the boiler and supplying the boiler with the drain stored in the drain tank;
An open tank that is open to the atmosphere and stores makeup water to be supplied to the boiler;
A drain relief line connecting the upstream side of the drain recovery valve in the drain recovery line and the open tank;
A drain relief valve disposed in the drain relief line;
A water level measuring unit for measuring the water level of the drain tank;
A storage unit for storing a target water level in the drain tank and a drain relief water level higher than the target water level;
A first water level control unit that controls the opening of the drain relief valve so that the water level of the drain tank becomes the target water level;
A closed-type boiler system comprising: a second water level control unit that closes the drain recovery valve and opens the drain relief valve when the water level of the drain tank exceeds the drain relief water level. The drain relief valve is
A first drain relief valve with adjustable opening;
A second drain relief valve capable of switching between an open state and a closed state, the drain relief line comprising:
A first drain relief line in which the first drain relief valve is disposed;
The boiler system of Claim 1 provided with the 2nd drain relief line by which the said 2nd drain relief valve is arrange | positioned. A first make-up water line connecting the open tank and the drain tank;
A first makeup water pump disposed in the first makeup water line;
A system stop control unit for stopping the boiler system when the water level of the drain tank exceeds an alarm water level higher than the drain escape water level;
The boiler system according to claim 1, further comprising: a makeup water control unit that drives the first makeup water pump when a water level of the drain tank falls below a makeup water supply water level lower than the target water level.

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