JP2015072096A - Steam heating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam heating system capable of achieving energy saving by making recyclable flash steam of steam heating equipment having a low heating capability.SOLUTION: A steam heating system includes: a steam generator 2 generating main steam; first steam loads 3A and 3B to which the main steam generated by the steam generator 2 is supplied; a second steam load 3C to which the main steam generated by the steam generator 2 is supplied, the second steam load 3C being lower in heating capability than the first steam loads 3A and 3B; a recovery unit 7 collecting drain and flash steam discharged from the first steam loads 3A and 3B and the second steam load 3C, and supplying the drain and the flash steam to the steam generator 2; and a pressure booster 6 provided between the second steam load 3C and the recovery unit 7, for boosting a pressure of the drain discharged from the second steam load 3C using the steam generated from the steam generator 2.

Description

  The present invention relates to a steam heating system.

In a general steam heating system, high-temperature and high-pressure steam is generated by a boiler. This high-temperature and high-pressure steam (hereinafter referred to as “basic steam”) is distributed after pressure adjustment to a plurality of steam heating facilities having different required heating capacities.
From the steam used in the steam heating facility, a drain which is a liquid in which the steam is condensed is discharged. By exposing the drain to a low pressure environment, steam having a pressure lower than that of the main steam (hereinafter referred to as flash steam) is generated.

  The flash vapor is collected together with the drain in a container called a drain tank and separated into gas and liquid. The drain divided in the container is used in a boiler or the like. On the other hand, the flash steam divided in the container may be reused for heating the water in the soft water tank used in the boiler, but in many cases, it is discharged outside the system without being reused.

  Patent Document 1 proposes to reuse the flash steam generated from the drain of the steam heating facility having a high heating capacity by mixing it with the supply steam of the steam heating facility having a lower heating capacity.

JP 2009-045780 A

  The above-described flash steam generally has a lower pressure than the main steam. When the basic steam supplied to one steam heating facility and the flash steam are mixed, the pressure of the mixed steam is lower than the pressure of the basic steam supplied to the steam heating facility. If steam having a low pressure is supplied to the steam heating facility in this way, the heating capability of the steam heating facility is reduced. Therefore, the reuse of the flash steam is limited to the case where the flush steam of the drain discharged from the steam heating facility having a high heating capacity is mixed with the main steam of the steam heating facility having a low heating capacity. Also in this case, the temperature and pressure of the flash steam generated from the drain of the steam heating facility with high heating capacity must be equal to or higher than the temperature and pressure of the main steam required for the steam heating facility with low heating capacity. It becomes.

On the other hand, in the steam heating system, the drains of a plurality of steam heating facilities having different heating capacities may be mixed and recovered. As described above, when the drains of the respective steam heating facilities are mixed and recovered, the pressure of the flash steam is equal to or lower than the pressure of the flash steam generated from the drain having the lowest pressure.
In other words, when flash steam obtained by mixing the drains of multiple steam heating facilities with different heating capacities is mixed with the main steam of the steam heating facility with the lowest heating capacity, the required heating capacity of this steam heating facility is reduced. You may not be satisfied.
This invention is made | formed in view of the said situation, and it aims at providing the steam heating system which can aim at energy saving by making reusable the flash steam of steam heating equipment with low heating capability.

In order to solve the above problems, the following configuration is adopted.
The steam heating system according to the present invention includes a steam generator that generates basic steam, a first steam load that is supplied with the basic steam generated by the steam generator, and the basic steam generated by the steam generator. And a second steam load having a heating capacity lower than that of the first steam load, a drain discharged from the first steam load and the second steam load, and the flash steam are recovered. The drain and the flash steam supplied to the steam generator, the steam is provided between the second steam load and the recovery unit, and the steam generated from the steam generator is used, And a pressure increasing section that increases the pressure of the drain discharged from the second steam load.
By increasing the pressure of the drain discharged from the second steam load by the pressure increasing portion, the pressure of the flash steam recovered by the recovery portion is discharged from the second steam load that has not increased the pressure. The pressure of the flash vapor generated from the drain can be increased. Therefore, the flash steam of the recovery unit can be mixed and reused with the basic steam used in the second steam load without reducing the heating capacity of the second steam load.
Further, since the drain recovered in the recovery unit has a higher pressure, the heat energy necessary for heating in the steam generation unit can be reduced by returning the drain to the steam generation unit.

Furthermore, in the steam heating system according to the present invention, the recovery unit in the steam heating system may include a drain tank that recovers the drain and a flash tank that recovers the flash steam.
By comprising in this way, the energy at the time of generating a vapor | steam by a steam generation part can be reduced by supplying the high voltage | pressure and high temperature drain collect | recovered by the drain tank to a steam generation part, and reusing. Further, the flash steam collected in the flash tank can be stably supplied to the second steam load.

Furthermore, the steam heating system according to the present invention may further include a steam compressor that mixes the flash steam with the main steam of the second steam load in the steam heating system.
By comprising in this way, since power is not required in order to mix flash steam and basic steam, further energy saving can be achieved.

Furthermore, in the steam heating system according to the present invention, in the steam heating system, at least one of the first steam load and the second steam load may be a steam turbine.
By comprising in this way, the flash steam discharged | emitted from a steam turbine can be reused, or a steam turbine can be driven using flash steam.

  According to the steam heating system, energy saving can be achieved by making it possible to reuse the flash steam of steam heating equipment having a low heating capacity.

It is a schematic structure figure of a steam heating system in one embodiment of this invention. It is a schematic block diagram of the steam compressor with which the said steam heating system is provided. It is a schematic block diagram of the drain collection | recovery pump of the said steam heating system, Comprising: The process of collect | recovering drains is shown. It is a schematic block diagram of the drain collection | recovery pump of the said steam heating system, Comprising: The state which the water level rose from the state shown in FIG. 3 is shown. It is a schematic block diagram of the drain collection | recovery pump of the said steam heating system, Comprising: The process of discharging | emitting a drain is shown. It is a schematic block diagram of the drain collection | recovery pump of the said steam heating system, Comprising: The state which the water level fell is shown rather than the state shown in FIG.

Hereinafter, a steam heating system according to an embodiment of the present invention will be described.
FIG. 1 is a diagram showing a schematic configuration of a steam heating system in this embodiment.
As shown in FIG. 1, the steam heating system 1 of this embodiment includes a boiler 2, steam heating facilities 3 </ b> A to 3 </ b> C, a pressure reducing valve 4, steam traps 5 </ b> A and 5 </ b> B, and a drain recovery pump (pressure increase unit) 6. A recovery unit 7, a steam compressor 8, and a soft water tank 9.
The boiler 2 heats water by burning fuel and generates high-pressure steam (saturated steam). The boiler is connected to basic piping for supplying the generated steam to the plurality of steam heating facilities 3A to 3C. The pressure of the steam generated by the boiler 2 is set to be equal to or higher than the pressure required by the steam heating facility having the highest heating capability among the plurality of steam heating facilities 3A to 3C. A safety valve 11 is attached in the middle of the main pipe 10 so that steam can escape to the outside when an abnormal pressure occurs.

  The steam heating facilities 3A to 3C are devices that operate using steam. In the steam heating facilities 3A to 3C in this embodiment, at least one of them is a steam turbine. The steam heating facilities 3A to 3C have different heating capacities. These steam heating facilities 3 </ b> A to 3 </ b> C are each connected to the main pipe 10 via the branch pipe 12. In the middle of the branch pipe 12, a pressure reducing valve 4 for reducing the pressure of the main steam to a pressure required by each of the steam heating facilities 3A to 3C is attached. That is, the pressure of the main steam flowing through the branch pipe 12 between the pressure reducing valve 4 and the steam heating facilities 3A to 3C is adjusted to a pressure required for each steam heating facility 3A to 3C. Here, in this embodiment, the case where the three steam heating facilities 3A to 3C are provided will be described as an example, but the number of the steam heating facilities is not limited to three as long as it is plural. The three steam heating facilities 3A to 3C in this embodiment are configured such that their respective heating capacities are steam heating facility 3A ≧ steam heating facility 3B> steam heating facility 3C.

  The steam trap 5A is a device that discharges a drain (condensed water) generated in the steam heating facility 3A while suppressing leakage of steam from the steam heating facility 3A. The steam trap 5A is attached in the middle of the drain pipe 13 of the steam heating facility 3A. Similarly, the steam trap 5B discharges the drain generated in the steam heating facility 3B while suppressing the leakage of steam from the steam heating facility 3B. The steam trap 5B is attached in the middle of the drain pipe 13 of the steam heating facility 3B.

  The drain recovery pump 6 is attached in the middle of the drain pipe 13 of the steam heating facility 3C having the lowest heating capability among the steam heating facilities 3A to 3C. The drain recovery pump 6 is a device that recovers the drain generated in the steam heating facility 3C at a high pressure. A high pressure supply pipe 14 is connected to the drain recovery pump 6. The high-pressure supply pipe 14 branches from the main pipe 10 and is connected to the drain recovery pump 6. A part of the basic steam can be supplied to the drain recovery pump 6 by the high-pressure supply pipe 14.

Each drain pipe 13 is joined and connected to the collective drain pipe 15. The collective drain pipe 15 is connected to the recovery unit 7.
The recovery unit 7 recovers the drain collected by the collecting drain pipe 15 and the flash vapor generated by re-evaporating the drain. That is, the drain and the flash vapor exist inside the collective drain pipe 15. The collection unit 7 includes a drain tank 16, a flash tank 17, and a control valve 18.

  The drain tank 16 is a tank that collects a liquid drain. The drain tank 16 can accommodate a predetermined amount of drain. A first drain supply pipe 19 is connected to the drain tank 16. The first drain supply pipe 19 is a pipe for supplying the drain in the drain tank 16 to the boiler 2. The drain accommodated in the drain tank 16 is reused in the boiler 2. A first flash supply pipe 20 is connected to the drain tank 16. The first flash supply pipe 20 is a pipe for supplying steam generated in the drain tank 16 to the soft water tank 9. The steam supplied to the soft water tank 9 via the first flash supply pipe 20 is used for heating water stored in the soft water tank 9.

  The flash tank 17 is a tank that collects gaseous flash vapor. The flash tank 17 can store a predetermined amount of flash steam. A second drain supply pipe 21 is connected to the flash tank. The second drain supply pipe 21 is a pipe for supplying a drain generated by condensation in the flash tank 17 to the boiler 2. The drain generated in the flash tank 17 is reused in the boiler 2. Further, a second flash supply pipe 22 is connected to the flash tank 17. The second flash supply pipe 22 supplies the flash vapor stored in the flash tank 17 to the steam compressor 8.

  The control valve 18 is a valve for gas-liquid separation of the drain and flash vapor in the collecting drain pipe 15. The drain separated through the control valve 18 is introduced into the drain tank 16, and the flash vapor separated through the control valve 18 is introduced into the flash tank 17.

  The steam compressor 8 is a device that generates medium to high pressure steam by mixing relatively low pressure steam with relatively high pressure steam. The steam compressor 8 is attached to a branch pipe 12 between the pressure reducing valve 4 for the steam heating facility 3 </ b> C and the main pipe 10. A pressure reducing valve 23 is attached to the branch pipe 12 between the steam compressor 8 and the main pipe 10 so that the pressure of the steam flowing into the steam compressor 8 can be adjusted.

FIG. 2 is a diagram showing a schematic configuration of the steam compressor 8.
As shown in FIG. 2, the steam compressor 8 sucks and mixes the low-pressure steam using the high-pressure steam as a driving fluid. The steam compressor 8 includes a high-pressure steam inlet 8a, a nozzle 8b, a suction chamber 8c, a suction port 8d, and a diffuser 8e. The high-pressure steam flowing in from the high-pressure steam inlet 8a is injected from the nozzle 8b into the suction chamber 8c. The injected steam travels straight toward the diffuser 8e. As a result, the pressure in the suction chamber 8c decreases. Then, low-pressure flash vapor is sucked up from the suction port 8d. At this time, the high-pressure steam and the low-pressure flash steam are mixed in the suction chamber 8c and are discharged from the steam compressor 8 through the diffuser 8e as medium-pressure steam.

In the steam compressor 8, the reverse flow of the steam to the low pressure side does not occur, and the pressure of each system of the high pressure steam and the low pressure steam is maintained. In the steam compressor 8 in this embodiment, the main steam of the main pipe is supplied as high-pressure steam, and the flash steam of the flash tank 17 is supplied as low-pressure steam. The steam obtained by mixing the basic steam and the flash steam is used as the basic steam of the steam heating facility 3C.
The soft water tank 9 replenishes the boiler 2 with water corresponding to the drain or steam discharged from the system. The soft water tank 9 stores soft water from which impurities are removed, and supplies the soft water to the boiler 2 as necessary. The soft water stored in the soft water tank 9 is heated by the flash steam generated in the drain tank 16.

3-6 is a figure which shows schematic structure of the drain collection | recovery pump 6 mentioned above. 3 and 4 show a process of collecting the drain. 5 and 6 show a process of discharging the drain.
As shown in FIG. 3, the drain recovery pump 6 includes a casing 30 that can accommodate the drain therein. In the casing 30, a drain inlet 32 is formed on the upper side of the side surface 31 a, and a drain outlet 33 is formed on the lower side thereof. These drain inlet 32 and drain outlet 33 are provided with check valves 34 and 35, respectively. The check valve 34 restricts the flow of fluid from the inside to the outside of the casing 30. The check valve 35 restricts the flow of fluid from the outside to the inside of the casing 30.

  A high-pressure steam inlet 36 to which the above-described high-pressure supply pipe 14 is connected is formed on the upper surface 31 b of the casing 30. The high-pressure steam inlet 36 is provided with a suction on-off valve 37 for opening and closing the high-pressure steam inlet 36. Further, a steam exhaust port 38 for discharging the gas in the casing 30 is formed on the upper surface 31b of the casing 30. The steam exhaust port 38 is provided with an exhaust on-off valve 39 for opening and closing the steam exhaust port 38. The intake opening / closing valve 37 and the exhaust opening / closing valve 39 are each connected to a switch mechanism 40.

  The switch mechanism 40 opens one of the intake on / off valve 37 and the exhaust on / off valve 39 and closes the other based on the water level of the drain in the casing 30. That is, the switch mechanism 40 switches between a state in which the basic steam is introduced into the casing 30 and a state in which the gas in the casing 30 is exhausted to the outside of the casing 30 based on the water level of the drain in the casing 30.

The drain recovery pump 6 of this embodiment has the above-described configuration. Next, the operation of the drain recovery pump 6 will be described with reference to FIGS.
As shown in FIGS. 3 and 4, when the drain water level in the casing 30 is lower than the upper point P <b> 1, the switch mechanism 40 closes the suction on-off valve 37 and opens the exhaust on-off valve 39. . In this state, the pressure p1 in the casing 30 is lower than the pressure p2 outside the check valve 35 of the drain discharge port 33 (p1 <p2). Therefore, there is no discharge of drain from the casing 30, and there is no inflow of drain from the drain discharge port 33 to the casing 30 by the check valve 35. In this state, the pressure p1 in the casing 30 is lower than the pressure p3 outside the check valve 34 (on the collecting drain pipe 15 side) of the drain inlet 32 (p1 <p3). The drain flows into the casing 30 from the drain pipe 13 of the steam heating facility 3C via the check valve 34.

  As shown in FIG. 5, when the inflow of the drain into the casing 30 continues, the water level in the casing 30 reaches the upper point P <b> 1 of the switch mechanism 40. When the water level reaches the upper point P1, the switch mechanism 40 in FIG. 5 opens the intake on-off valve 37 and closes the exhaust on-off valve 39. In this state, high-pressure steam, which is basic steam, is supplied into the casing 30, so that the pressure p <b> 1 in the casing 30 becomes higher than the pressure p <b> 3 outside the drain inlet 32 (on the steam heating facility 3 </ b> C side). (P1> p3). Therefore, the inflow of the drain from the drain inlet 32 into the casing 30 is stopped. Furthermore, when the pressure p1 in the casing 30 becomes higher than the pressure p2 outside the check valve 35 (on the side of the collecting drain pipe 15), the drain in the casing 30 is connected to the check valve from the drain outlet 33. It is discharged to the collecting drain pipe 15 side through 35.

  Next, as shown in FIG. 6, the state in which the drain in the casing 30 is discharged from the drain outlet 33 is continued, and the water level in the casing 30 is lowered. When the water level in the casing 30 decreases to the lower point P2, the switch mechanism 40 closes the suction on-off valve 37 again and opens the exhaust on-off valve 39. That is, returning to the state shown in FIG. 3, the switch mechanism 40 repeats the above-described operation. As a mechanism for detecting the upper point P1 and the lower point P2 in the switch mechanism 40, various methods can be used. As an example of the mechanism, for example, a method of detecting the water level with a float, switching the state of a contact (not shown) based on this water level, and switching the states of the intake on-off valve 37 and the exhaust on-off valve 39, etc. Can be used. Here, the amount of basic steam used in the drain recovery pump 6 described above is sufficiently smaller than the amount of flash steam reused in the steam heating facility 3C. That is, the entire basic steam can be reduced by reusing the flash steam.

  Therefore, according to the steam heating system 1 of the above-described embodiment, the drain recovery pump 6 can increase the drain pressure of the steam heating facility 3C and mix it with the drains of the steam heating facilities 3A and 3B. Therefore, the pressures of the drain collected in the drain tank 16 of the collection unit 7 and the flash steam collected in the flash tank 17 can be increased. As a result, the pressure of the steam obtained by mixing the flash steam collected in the flash tank 17 into the main steam can be made higher than the pressure of the flash steam generated from the drain of the steam heating equipment 3C. The drain of the steam heating facility 3C can be effectively reused without reducing the heating capacity. In addition, since the drain recovered in the recovery unit 7 can be set to a higher pressure, the heat energy necessary for heating in the boiler 2 can be reduced by returning the drain to the boiler 2.

  Furthermore, since the high-pressure and high-temperature drain collected by the drain tank 16 can be supplied to the boiler 2 and reused, the energy for heating the water by the boiler 2 can be reduced. Further, by providing the flash tank 17, the flash steam recovered in the flash tank 17 can be stably supplied to the steam heating facility 3C.

Further, by providing the steam compressor 8, no power is required when mixing the flash steam of the flash tank 17 and the main steam supplied from the main pipe 10, so that further energy saving can be achieved. .
Furthermore, since the steam heating facilities 3A, 3B, and 3C are steam turbines, the flash steam discharged from the steam turbine can be reused, or the steam turbine can be driven using the flash steam. As a result, the steam heating system 1 can be driven with less energy. In this embodiment, the case where all of the steam heating facilities 3A to 3C are steam turbines has been described. However, if any one of the steam heating facilities 3A, 3B and the steam heating facility 3C is a steam turbine, the number is less. The steam heating system 1 including the steam turbine can be driven with energy.

  Note that the present invention is not limited to the above-described embodiments, and includes various modifications made to the above-described embodiments without departing from the spirit of the present invention. That is, the specific shapes, configurations, and the like given in the embodiment are merely examples, and can be changed as appropriate.

  For example, in each embodiment mentioned above, the example which heats the soft water stored in the soft water tank 9 using the flash vapor | steam generate | occur | produced in the drain tank 16 was demonstrated. However, the present invention is not limited to this configuration. For example, the flash vapor generated in the drain tank 16 may be discharged to the outside.

In embodiment mentioned above, the case where steam heating equipment 3A-3C was a steam turbine was demonstrated. However, the steam heating facilities 3A to 3B are not limited to the steam turbine. In addition to the steam turbine, a heating device using steam may be used.
Moreover, in embodiment mentioned above, although the case where three steam heating installations were provided was demonstrated, what is necessary is just to provide the two steam heating installations from which heating capability differs at least.

Furthermore, in the embodiment, the case where the collection unit 7 includes the drain tank 16 and the flash tank 17 has been described as an example. However, the configuration is not limited to this. For example, only the drain tank 16 may be provided, and the flash vapor generated in the drain tank 16 may be supplied to the steam compressor 8 and reused.
In the drain recovery pump 6 of the embodiment, the case where the drain inlet 32 and the drain outlet 33 are formed on the same side surface 31a has been described as an example, but may be formed on different side surfaces.

  Furthermore, it is not restricted to the structure of the switch mechanism 40 of embodiment mentioned above. Any structure may be used as long as it detects the water levels corresponding to the upper point P1 and the lower point P2 and can switch between the open / close states of the intake open / close valve 37 and the exhaust open / close valve 39.

1 Steam heating system 2 Boiler (steam generator)
3A Steam heating equipment (first steam load)
3B Steam heating equipment (first steam load)
3C steam heating equipment (second steam load)
4 Pressure reducing valve 5 Steam trap 6 Drain recovery pump (pressure riser)
DESCRIPTION OF SYMBOLS 7 Recovery part 8 Steam compressor 8a High pressure steam inlet 8b Nozzle 8c Suction chamber 8d Suction port 8e Diffuser 9 Soft water tank 10 Core piping 11 Safety valve 12 Branch piping 13 Drain pipe 14 High pressure supply pipe 15 Collecting drain pipe 16 Drain tank 17 Flash tank 18 Control Valve 19 First drain supply pipe 20 First flash supply pipe 21 Second drain supply pipe 22 Second flash supply pipe 23 Pressure reducing valve 30 Casing 31a Side face 31b Upper face 32 Drain inlet 33 Drain outlet 34 Check valve 35 Check valve 35 36 High-pressure steam inlet 37 Open / close valve for suction 38 Steam exhaust port 39 Open / close valve for exhaust 40 Switch mechanism P1 Upper point P2 Lower point

Claims (4)

A steam generator for generating basic steam;
A first steam load to which the basic steam generated by the steam generating unit is supplied;
A main steam generated by the steam generation unit is supplied, a second steam load having a heating capacity lower than that of the first steam load;
A drain discharged from the first steam load and the second steam load, and a recovery unit for recovering the flash steam and supplying the drain and the flash steam to the steam generation unit;
A pressure increasing unit that is provided between the second steam load and the recovery unit and increases the pressure of the drain discharged from the second steam load by using the steam generated from the steam generating unit. When,
A steam heating system comprising: The collection unit
A drain tank for collecting the drain;
A flash tank for collecting flash steam;
A steam heating system according to claim 1.   The steam heating system according to claim 1, further comprising a steam compressor that mixes the flash steam with the main steam of the second steam load.   The steam heating system according to any one of claims 1 to 3, wherein at least one of the first steam load and the second steam load is a steam turbine.

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