JP2016161220A - Boiler system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boiler system capable of improving utilization efficiency of heat while being maintained in a suitable operation state.SOLUTION: A boiler system 1 is provided with: a boiler 10; a drain tank 20; a drain recovery line L2 for connecting first load equipment 40 with the drain tank 20; a drain supply line L3 for supplying drain accommodated in the drain tank 20 to the boiler 10; an open tank 30; a first flash steam line L51 for supplying flash steam generated in the drain tank 20 to the open tank 30; a second flash steam line L52 for supplying the flash steam to second load equipment 50; a first pressure regulating valve 51 whose opening is regulated so that pressure on a primary side in the first flash steam line L51 becomes first setting pressure; and a second pressure regulating valve 52 whose opening is regulated so that the pressure on the primary side in the second flash steam line L52 becomes second setting pressure lower than the first setting pressure.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, the flash steam generated from the drain in the drain tank is released to the open tank side opened to the atmosphere, and the pressure on the primary side of the flash steam line arranged in the flash steam line is a predetermined pressure. And a pressure adjusting valve that adjusts so as to be (see, for example, Patent Document 1).
Thereby, the flash steam generated in the drain tank is supplied to the open tank and used for heating the water stored in the open tank, thereby recovering the heat held by the flash steam.

JP 2013-204961 A

  By the way, the pressure inside the drain tank is required to be kept within a predetermined range in order to stably operate the boiler system. For this reason, depending on the operation status of the boiler system, a large amount of flash steam may be released to the open tank in order to reduce the pressure inside the drain tank to a suitable range. Thus, when the generation amount of flash steam increases, the heat held by the flash steam cannot be sufficiently recovered by the water stored in the open tank.

  Therefore, an object of this invention is to provide the boiler system which can improve the utilization efficiency of heat, maintaining a suitable driving | running state.

  The present invention provides a boiler that generates steam and supplies it to the first load device, a drain tank that collects the drain that is generated by the condensation of the first load device by using steam without opening it to the atmosphere, A drain recovery line that connects the first load device and the drain tank, a drain supply line that connects the drain tank and the boiler and supplies the drain accommodated in the drain tank to the boiler, and is opened to the atmosphere. An open tank for storing makeup water to be supplied to the boiler; a first flash steam line for connecting the drain tank and the open tank to supply flash steam generated in the drain tank to the open tank; and the drain A tank and a second load device are connected to supply flash vapor generated in the drain tank to the second load device. A second flash steam line; a first pressure regulating valve disposed in the first flash steam line, the first pressure regulating valve having an opening adjusted so that a primary pressure in the first flash steam line becomes a first set pressure; A second pressure regulating valve disposed in the second flash steam line, the opening of which is adjusted so that the primary pressure in the second flash steam line becomes a second set pressure lower than the first set pressure; The present invention relates to a closed type boiler system.

  According to the boiler system of the present invention, heat utilization efficiency can be improved while maintaining a suitable operation state.

It is a figure showing the composition of the boiler system concerning one embodiment of the present invention.

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, and the open tank 30 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, as lines, a first steam supply line L1, a drain recovery line L2, a drain supply line L3, a second steam supply line L4, a first flash steam line L51, 2 flush steam line L52, 1st makeup water line L6, drain return line L7, drain escape line L8, and 2nd 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 the steam to the first load device 40.
The first 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. This drain tank 20 collect | recovers the drain produced by condensing the steam produced | generated by the once-through boiler 11 with the 1st load apparatus 40 in a high temperature / high pressure state.

  The open tank 30 is open to the atmosphere. The open tank 30 stores makeup water supplied to the once-through boiler 11. Also, the open tank 30 is introduced with the flash steam generated from the drain in the drain tank 20 and flowing through the first flash steam line L51 described later, and the drain flowing through the drain escape line L8 described later.

The first steam supply line L <b> 1 connects the steam header 12 and the first load device 40, and supplies the steam generated by the plurality of once-through boilers 11 to the first load device 40.
The drain recovery line L <b> 2 connects the first load device 40 and the drain tank 20, and supplies the drain generated in the first 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 downstream of the first load device 40 in the drain recovery line L2, discharges the drain generated in the first 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 first 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 constituted by a motor valve, 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 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 drain supply valve 32 is constituted by a motor valve, and adjusts the amount of drain supplied to the plurality of once-through boilers 11 by adjusting the opening degree.

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 first flash steam line L51 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. A first pressure regulating valve 51 is disposed in the first flash steam line L51.
The opening of the first pressure regulating valve 51 is adjusted so that the primary pressure in the first flash steam line L51 becomes the first set pressure (for example, 0.5 MPa). That is, when the pressure inside the drain tank 20 exceeds the first set pressure, the first pressure regulating valve 51 releases the flash steam to the open tank 30 side, and reduces the pressure inside the drain tank 20.

The second flash steam line L52 connects the drain tank 20 and the second load device 50, and supplies the flash steam generated in the drain tank 20 to the second load device 50. In the present embodiment, the primary side end of the second flash steam line L52 is connected to the primary side of the first pressure regulating valve 51 in the first flash steam line L51. A second pressure regulating valve 52 is disposed in the second flash steam line L52.
The opening of the second pressure regulating valve 52 is adjusted so that the primary pressure in the second flash steam line L52 becomes a second set pressure (eg, 0.3 MPa) lower than the first set pressure. That is, the second pressure regulating valve 52 circulates the flash vapor to the second load device 50 side when the pressure inside the drain tank 20 exceeds the second set pressure.

  The second load device 50 performs direct heating or indirect heating of an object to be heated using a relatively low-pressure steam flowing through the second flash steam line L52 as a heat source.

  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.
A drain relief valve 81 is disposed in the drain relief line L8. The drain relief valve 81 is configured by a motor valve or an electromagnetic valve that can be switched between an open state and a closed state. The drain relief valve 81 opens and closes the flow path of the drain relief line L8.

  That is, in the present embodiment, when the drain flowing through the drain recovery line L2 is recovered in the drain tank 20, the drain recovery valve 23 is opened and the drain relief valve 81 is closed. On the other hand, when draining through the drain recovery line L2 to the open tank 30, the drain recovery valve 23 is closed and the drain relief valve 81 is opened.

  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.

Next, operation | movement of the boiler system 1 of this embodiment is demonstrated. In the present embodiment, first, steam is generated in the plurality of once-through boilers 11. Steam generated in the plurality of once-through boilers 11 is supplied to the steam header 12 via the connecting pipe 13.
The steam supplied to the steam header 12 becomes drain after being used in the first load device 40 and is stored in the drain tank 20 in a high temperature and high pressure state. The drain stored in the drain tank 20 is supplied as feed water to the once-through boiler 11 through the drain supply line L3.

  Here, the pressure inside the drain tank 20 is required to be kept within a predetermined range in order to stably operate the boiler system 1. Therefore, depending on the operation status of the boiler system 1, a large amount of flash steam may be discharged to the outside in order to reduce the pressure inside the drain tank 20 to a suitable range. Therefore, in the present embodiment, the boiler system 1 uses the first flash steam line L51 for supplying the flash steam generated in the drain tank 20 to the open tank 30 and the second flash steam for supplying the flash steam to the second load device 50. The first pressure regulating valve 51 whose opening is adjusted so that the pressure on the primary side of the line L52, the first flash steam line L51 becomes the first set pressure (for example, 0.5 MPa), and the second flash steam line L52. And a second pressure regulating valve 52 whose opening is adjusted so that the primary side pressure becomes a second set pressure (for example, 0.3 MPa) lower than the first set pressure.

  As a result, when the pressure inside the drain tank 20 exceeds the second set pressure, the second pressure regulating valve 52 allows the flush steam to escape to the secondary side, so that the flush steam generated inside the drain tank 20 is removed. The second load device 50 can be supplied through the second flash vapor line L52. In this state, when the internal pressure of the drain tank 20 further increases and exceeds the first set pressure, the first pressure regulating valve 51 also releases the flash steam to the secondary side, thereby opening the flash steam. 30 to prevent the pressure inside the drain tank 20 from rising too much. Therefore, since excessive flash steam can be supplied to the second load device 50 while preventing the pressure inside the drain tank 20 from exceeding the first set pressure, the boiler system 1 is suitably operated and the boiler is maintained. The heat utilization efficiency of the system 1 can be improved.

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

  In the closed-type boiler system 1, the flash steam generated in the drain tank 20 is supplied to the open tank 30 and used for heating makeup water. However, when the amount of flash steam generated increases, the heat retained by the flash steam cannot be sufficiently recovered by the makeup water. Therefore, the boiler system 1 includes a first flash steam line L51 for supplying flash steam to the open tank 30, a second flash steam line L52 for supplying flash steam to the second load device 50, and a first flash steam line L51. A first pressure regulating valve 51 whose opening is adjusted so that the primary side pressure becomes the first preset pressure, and a second preset pressure in which the primary side pressure of the second flash steam line L52 is lower than the first preset pressure; And a second pressure regulating valve 52 whose opening degree is adjusted to be configured. As a result, when the internal pressure of the drain tank 20 is between the second set pressure and the first set pressure, the flash steam generated in the drain tank 20 is supplied to the second load device 50 that uses low-pressure steam. In addition, when the internal pressure of the drain tank 20 exceeds the first set pressure, the internal pressure of the drain tank 20 can be prevented from excessively rising by supplying flash steam to the open tank 30. . Therefore, since excessive flash steam can be supplied to the second load device 50 while preventing the pressure inside the drain tank 20 from exceeding the first set pressure, the boiler system 1 is suitably operated and the boiler is maintained. The heat utilization efficiency of the system 1 can be improved.

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.

1 Boiler system 10 Boiler equipment (Boiler)
20 Drain tank 30 Open tank 40 First load device 50 Second load device 51 First pressure adjustment valve 52 Second pressure adjustment valve L2 Drain recovery line L3 Drain supply line L51 First flash steam line L52 Second flash steam line

Claims (1)

A boiler that generates steam and supplies it to the first load device;
A drain tank for collecting the drain produced by the condensation of the first load device by using steam without opening it to the atmosphere;
A drain recovery line connecting the first load device and the drain tank;
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 first flash steam line that connects the drain tank and the open tank and supplies flash steam generated in the drain tank to the open tank;
A second flash steam line connecting the drain tank and a second load device to supply the flash steam generated in the drain tank to the second load device;
A first pressure regulating valve disposed in the first flash steam line and having an opening adjusted so that a primary pressure in the first flash steam line becomes a first set pressure;
A second pressure regulating valve disposed in the second flash steam line, the opening of which is adjusted so that a primary pressure in the second flash steam line becomes a second set pressure lower than the first set pressure; Closed type boiler system with

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