JPH11351507A - Deaerator for steam turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the mixture of bubbles in the water sent out from water outlet sections when the pressure in a deaerator tank drops. SOLUTION: A deaerator is constituted of a horizontal deaerator tank 1 having a water storage section 4 for storing water and a steam jetting section 5 which jets heated steam into the water stored in the section 4. On the upper left side of the tank 1, a water inlet section 2 through which water is taken in the tank 1 is provided and, in the bottom section of the tank 1, a pair of water outlet sections 6a and 6b respectively provided with stop valves 14a and 14b for feeding water to a steam generator are provided. The water outlet sections 6a and 6b are composed of a normally-used water outlet section 6a provided in the right side of the tank 1 and a by-pass water outlet section 6b provided in the left side of the tank 1 correspondingly to the water inlet section 2. When the pressure in the tank 1 drops, the valve 14a is closed and the valve 14b is opened (contrary to the normally operating time).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deaerator for a steam turbine for performing heating and deaeration of water supplied to a steam generator by heating steam.

[0002]

2. Description of the Related Art For example, in a water supply system of a steam turbine of a thermal power plant or the like, a deaerator for removing dissolved oxygen in feed water in order to suppress corrosion of a steam generator and a water supply pipe such as a boiler. Is generally used. The deaeration of dissolved oxygen by such a deaerator is usually performed by heating the feed water with heated steam to a saturation temperature, and further exposing the feed water to air-free steam.

[0003] Conventional deaerators include, for example, a deaeration tray type deaerator and a bubbling type deaerator. In the former method, the supply water is formed into a liquid film or droplets by spraying or the like, collected in a degassing tray, converted into droplets again, and heated and degassed by contact with heated steam. In the latter, heating steam is blown out into a water reservoir that stores the sprayed water supply to form a number of bubbles, and the contact area between the water supply and the heating steam is increased to promote heating and degassing. is there.

FIG. 5 shows an example of such a conventional bubbling type deaerator. In FIG. 5, the steam turbine deaerator has a horizontal deaerator tank 1 having a water storage part 4 for storing water supply therein, and a heater for jetting heated steam into the water supply in the water storage part 4 of the tank 1. A steam jetting section 5 having a plurality of steam jet nozzles 50.

[0005] Further, a water supply inlet 2 for taking in water from a condenser into the tank 1 is provided at an upper left portion of the tank 1 in FIG. This water inlet 2
Has an inlet pipe 20 into which water supplied from the condenser flows, and a water supply nozzle 22 for spraying the water supplied into the inlet pipe 20 into the tank 1 in a thin film form. Note that an air outlet 13 is formed in the tank 1 in the vicinity of the water supply inlet 2.

On the other hand, a water supply outlet 6 for supplying water to a boiler (steam generator) is provided at the right bottom of the tank 1 in FIG. The water supply outlet 6 has an outlet pipe 60 from which the supply water flows out and the on-off valve 14. The water supply outlet 6 is connected to a water supply pipe 9 arranged below the tank 1, and a water supply pump 8 is connected to the water supply pipe 9.
Is interposed.

In such a deaerator, the water supply inlet 2
The water supplied from the water supply nozzle 22 into the tank 1 is
It falls into the water storage part 4 in the tank 1, and in the water storage part 4,
The steam flows to the water supply outlet 6 while being heated while being in direct contact with the bubbles of the heated steam injected from the injection nozzle 50 of the steam jetting unit 5. Then, the supply water heated and degassed by the heating steam enters the supply pipe 9 from the supply water outlet 6 and is supplied to the supply pump 8.
Sent to the boiler.

When the bubbles of the heated steam jetted from the jet nozzle 50 of the steam jetting section 5 rise in the water storage 4 and reach the steam space 12 in the upper part of the tank 1, the water supply nozzle 22 feeds the tank 1. Again, it comes into direct contact with the water supplied as a thin film. The heated steam in contact with the feedwater in the steam space 12 also heats and degass the feedwater.
Oxygen and associated vapor separated from the water supply by degassing are discharged from the air outlet 13 to the outside of the tank 1.

[0009]

However, in the conventional steam turbine deaerator as described above, when the pressure in the deaerator tank 1 decreases due to a change in the steam turbine load, the water supplied from the water supply outlet 6 is supplied. There is a problem that air bubbles may be mixed into the air.

That is, during normal operation of the steam turbine, the pressure in the tank 1 is kept almost constant, and the temperature of the water supply in the water storage section 4 is kept almost equal to the saturation temperature in the tank 1. However, when the pressure in the deaerator tank 1 decreases due to a load change such as a load drop or a load cutoff of the steam turbine, the saturation temperature in the tank 1 also decreases. For this reason,
In particular, the water supply in the water storage unit 4 that has become hot at the water supply outlet 6 side causes a flash phenomenon (evaporation), and the amount of steam bubbles in the water supply increases from that in the normal operation.

For this reason, the air bubbles mixed into the water supply are sent out from the water supply outlet 6 to the boiler (steam generator) side together with the water supply, which may adversely affect various devices and pipes.

The present invention has been made in view of such a point, and when the pressure in the deaerator tank drops due to a change in the load of the steam turbine, bubbles are generated in the feedwater sent from the feedwater outlet to the steam generator. It is an object of the present invention to provide a steam turbine deaerator that can prevent the mixing of water.

[0013]

A first aspect of the present invention is a horizontal deaerator having a water storage portion for storing a supply water therein in a deaerator for a steam turbine for deaeration of a supply water to a steam generator. Container tank, a steam ejection portion for ejecting heated steam into the water supply in the water storage portion of the tank, and a water supply inlet portion provided at an upper end of one end of the tank to take in water into the tank, A plurality of water supply outlets provided at the bottom of the tank and having an on-off valve for sending out water to the steam generator, the plurality of water supply outlets being arranged at the other end of the tank. It is characterized by comprising a service water supply outlet, and one or more bypass water supply outlets located closer to one end of the tank than the service water supply outlet.

According to the first means, during normal operation, the open / close valve at the regular water supply outlet is opened and the open / close valve at the bypass water supply outlet is closed, so that the water supplied from the water supply inlet is opened. Is sufficiently heated and degassed by the heated steam blown out from the steam blowout part in the water storage part, and then sent out from the service water outlet part to the steam generator.

On the other hand, when the pressure in the deaerator tank drops due to a change in the steam turbine load, the gas is taken in from the water supply inlet by closing the on-off valve at the regular water supply outlet and opening the on-off valve at the bypass water supply outlet. The supplied water is sent from the bypass water supply outlet to the steam generator before being sufficiently heated by the heated steam jetted from the steam jet in the water storage. As a result, the temperature of the feedwater near the bypass feedwater outlet is reduced in response to the decrease in the saturation temperature due to the decrease in the pressure in the deaerator tank, and the increase in bubbles caused by flashing (evaporation) in the feedwater is prevented. can do.

A second means is a deaerator for a steam turbine for deaeration of water supplied to a steam generator, a horizontal deaerator tank having a water storage portion for storing water therein, and this tank. A steam spouting section for spouting heated steam into the water supply in the water storage section, a plurality of water supply inlets provided at an upper portion of the tank, and having an on-off valve for taking in water into the tank, A water supply outlet for supplying water to the steam generator is provided at a bottom of one end of the tank, and the plurality of water supply inlets are a regular water supply inlet disposed at the other end of the tank. It is characterized by comprising one or more bypass water inlets disposed at a position closer to one end of the tank than the regular water inlet.

According to the second means, during normal operation, the on-off valve at the service water inlet is opened and the on-off valve at the bypass water inlet is closed to take in the water from the service water inlet. The water supply is sufficiently heated and degassed by the heated steam blown out from the steam blowout part in the water storage part, and then sent out from the water supply outlet part to the steam generator.

On the other hand, when the pressure in the deaerator tank drops due to a change in the load of the steam turbine, the on-off valve at the service water inlet is closed and the on-off valve at the bypass water inlet is opened to take in the air from the bypass water inlet. The water supply was
Before being sufficiently heated by the heated steam ejected from the steam ejection portion in the water storage portion, the water is sent from the water supply outlet portion to the steam generator. Accordingly, in response to the decrease in the saturation temperature due to the decrease in the pressure in the deaerator tank, the temperature of the feedwater near the feedwater outlet is lowered, and the increase in bubbles caused by flashing (evaporation) in the feedwater is prevented. be able to.

The third means is to omit the on-off valve at the bypass water supply inlet section, assuming that the complete deaeration effect of the water supply is not required in the second means, and to provide the normal water supply inlet during normal operation. Water is supplied from both the water supply section and the bypass water supply inlet.

The fourth means is the second means, further comprising an internal pipe extending from the bypass water supply inlet to above the water supply outlet in the tank, and further comprising an internal pipe in the deaerator tank due to a change in steam turbine load. When the pressure drops, the water supply is directly bypassed from the bypass water supply inlet to the water supply outlet via the internal piping.

Fifth means is a deaerator for a steam turbine for deaeration of feed water to a steam generator, wherein a deaerator tank having a water storage portion for storing feed water therein, A steam spouting section for spouting heated steam into the water supply in the water storage section, a water supply inlet provided at an upper portion of the tank, for taking in water into the tank, and a water supply outlet provided at a bottom of the tank And a water supply pipe connecting the water supply outlet with the steam generator, and a water supply pipe provided with a water supply pump, and a branch from the downstream side of the water supply pump in the water supply pipe, and the water supply inlet through an on-off valve. And a communication pipe connected to the section.

According to the fifth means, during normal operation, the on-off valve of the communication pipe is closed, and the supply water taken in from the supply water inlet is heated steam discharged from the steam supply section in the water storage section. After being heated and degassed sufficiently, the water is sent out from the water supply outlet to the steam generator.

On the other hand, when the pressure in the deaerator tank drops due to a change in the steam turbine load, a part of the high-temperature feedwater sent from the feedwater outlet to the feedwater pipe is opened by opening the on-off valve of the connecting pipe. It is returned from the connecting pipe to the deaerator tank via the water supply inlet. The high-temperature feedwater returned to the deaerator tank flashes in the tank to generate steam, and compensates for a decrease in the pressure in the deaerator tank to suppress a decrease in the saturation temperature. Thus, it is possible to prevent an increase in bubbles due to flashing (evaporation) in the water supply near the water supply outlet.

According to a sixth aspect, in the fifth aspect, the connecting pipe is directly connected to the tank near the water supply inlet, and the operation is basically the same as that of the fifth aspect. It is.

[0025]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 to 4 are views showing an embodiment of a steam turbine deaerator according to the present invention.
In the embodiment of the present invention shown in FIGS. 1 to 4, the same components as those of the conventional example shown in FIG.

[First Embodiment] First, a first embodiment of the present invention will be described with reference to FIG. In FIG.
A deaerator for a steam turbine for deaeration of feed water to a boiler (steam generator) has a water storage unit 4 for storing feed water therein.
And a steam jetting section 5 for jetting heated steam into the water supply in the water storage section 4 of the tank 1.

The steam jetting section 5 has a steam inlet pipe 10 for introducing heated steam, a steam header 11 extending from the lower end of the steam inlet pipe 10 to both sides in the longitudinal direction of the tank 1, and a lower part from the steam header 11. And a plurality of steam injection nozzles 50 extending therefrom.
Is configured to inject steam into the supply water at

Further, a water supply inlet 2 for taking in water from a condenser into the tank 1 is provided at an upper portion on the left side (one end side) of the tank 1 in FIG. This water inlet 2 is an inlet pipe 2 into which water from the condenser flows.
0, and a water supply nozzle 22 for spraying the water supplied into the inlet pipe 20 into the tank 1 in a thin film form. In addition,
An air outlet 13 is formed in the tank 1 near the water supply inlet 2.

On the other hand, at the bottom of the tank 1, a pair of water supply outlets 6a and 6b for supplying water to a boiler (steam generator) are provided. This pair of water supply outlets 6
a, 6b are provided on the right side (the other end side) of the tank 1 in FIG. 1 and on the left side (one end side) of the tank 1 in FIG. And a bypass water supply outlet 6b.

The water supply outlets 6a and 6b are respectively connected to outlet pipes 60a and 60b from which feed water flows and open / close valves 14a and 14b.
b. And each water supply outlet 6a, 6b
Are respectively connected to water supply pipes 9 arranged below the tank 1. In addition, each water supply outlet 6 in the water supply pipe 9
A water supply pump 8 is interposed downstream of a and 6b.

Next, the operation and effect of this embodiment having the above configuration will be described. According to the present embodiment, during normal operation, the open / close valve 14 of the service water outlet 6a
a is opened, and the on-off valve 14b of the bypass water supply outlet 6b is closed, so that the water supplied from the water supply inlet 2 is supplied to the injection nozzle 5 of the steam discharge unit 5 in the water storage 4.
After being sufficiently heated and degassed by the heated steam ejected from 0, it is sent out to the boiler from the service water outlet 6a.

That is, the water supply nozzle 22 of the water supply inlet 2
The water supply injected into the tank 1 from the tank falls into the water storage section 4 in the tank 1, and is heated in the water storage section 4 by directly contacting the bubbles of the heated steam injected from the injection nozzle 50 of the steam ejection section 5. Then, it flows to the service water outlet 6a. Then, the supply water sufficiently heated and degassed by the heating steam enters the supply pipe 9 from the regular supply outlet 6a and is sent to the boiler by the supply pump 8.

The bubbles of the heated steam jetted from the jet nozzle 50 of the steam jetting section 5 rise in the reservoir 4 and reach the steam space 12 in the upper part of the tank 1. Again, it comes into direct contact with the water supplied as a thin film. The heated steam in contact with the feedwater in the steam space 12 also heats and degass the feedwater.
Oxygen and associated vapor separated from the water supply by degassing are discharged from the air outlet 13 to the outside of the tank 1.

On the other hand, when the pressure in the deaerator tank 1 decreases due to a change in the load of the steam turbine, the service water outlet 6
By opening the on-off valve 14a of the a and opening the on-off valve 14b of the bypass water supply outlet 6b, the water supplied from the water supply inlet 2 is heated in the water reservoir 4 by the injection nozzle 50 of the steam injection unit 5 Before being sufficiently heated by the steam, the water is sent out from the bypass water supply outlet 6b to the boiler.

Thus, the temperature of the feedwater near the bypass feedwater outlet 6b is reduced in response to the decrease in the saturation temperature caused by the decrease in the pressure in the deaerator tank 1, and the flash (evaporation) of the feedwater is performed. Since it is possible to prevent an increase in air bubbles, it is possible to prevent air bubbles from being mixed into the water supplied from the bypass water supply outlet 6b to the boiler.

It should be noted that another bypass water supply outlet is provided between the regular water supply outlet 6a and the bypass water supply outlet 6b.
Alternatively, two or more may be provided.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment,
As shown in FIG. 2, instead of the pair of water supply outlets 6a, 6b, only the water supply outlet 6 corresponding to the regular water supply outlet 6a is provided, and the opening / closing valve 17a is provided instead of the water supply inlet 2. , 17b having a pair of water supply inlets 2a, 2b
The second embodiment differs from the first embodiment in that b is provided, and the other configuration is substantially the same as that of the first embodiment shown in FIG.

Specifically, the pair of water supply inlets 2a,
2b is disposed on the right side (one end side) of the tank 1 in FIG. 2 corresponding to the regular water supply inlet section 2a disposed on the left side (the other end side) of the tank 1 in FIG. And a bypass water supply inlet 2b.

Each of the water supply inlets 2a, 2b has an inlet pipe 20a, 20b similar to the inlet pipe 20 and the water supply nozzle 22 of the water supply inlet 2 shown in FIG. 1 in addition to the on-off valves 17a, 17b. And water supply nozzles 22a and 22b. In addition, the inlet pipe 2 of each water supply inlet part 2a, 2b.
Reference numerals 0a and 20b extend downward from the condenser-side water supply pipe 30 disposed above the tank 1, respectively.

Next, the operation and effect of this embodiment having the above configuration will be described. According to the present embodiment, during normal operation, the open / close valve 17 of the service water inlet 2a is used.
a is opened, and the on-off valve 17b of the bypass water supply inlet 2b is closed, so that the supply water taken in from the regular supply water inlet 2a is heated steam injected from the injection nozzle 50 of the steam injection unit 5 in the water storage unit 4. Heating enough
After being degassed, it is sent out from the water supply outlet 6 to the boiler.

On the other hand, when the pressure in the deaerator tank 1 decreases due to a change in the steam turbine load, the service water inlet 2
a of the bypass feed water inlet 2b by closing the open / close valve 17a of the bypass feed water inlet 2b.
Is supplied from the water supply outlet 6 to the boiler before being sufficiently heated by the heated steam ejected from the injection nozzle 50 of the steam ejection unit 5 in the water storage unit 4.

Accordingly, the temperature of the feedwater near the feedwater outlet 6 is reduced in response to the decrease in the saturation temperature due to the decrease in the pressure in the deaerator tank 1, and the increase in bubbles caused by the flush in the feedwater is reduced. Since this can be prevented, it is possible to prevent bubbles from being mixed in the water supplied from the water supply outlet 6 to the boiler.

In the present embodiment, when the complete deaeration effect of the feed water is not required, the on-off valve 17b of the bypass feed water inlet 2b is omitted, and the normal feed water inlet 2a and the bypass feed water 2a are not operated during the normal operation. Water supply may be taken in from both of the inlets 2b.

Further, another bypass water inlet 1 is provided between the regular water inlet 2a and the bypass water inlet 2b.
Alternatively, two or more may be provided.

As shown by a two-dot chain line in FIG. 2, an internal pipe 40 extending from the bypass water supply inlet 2b to above the water supply outlet 6 in the tank 1 is provided. When the internal pressure is reduced, the water supply may be directly bypassed from the bypass water supply inlet 2b to the water supply outlet 6 via the internal pipe 40.

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIG. In this embodiment,
As shown in FIG. 2, instead of the pair of water supply outlets 6a and 6b, only the water supply outlet 6 corresponding to the regular water supply outlet 6a is provided, and the water supply pipe 9 is provided from the downstream side of the water supply pump 8. The second embodiment differs from the first embodiment in that a connecting pipe 18 is provided which is branched and connected to the water supply inlet 2 via the on-off valve 19 (via the condenser-side water supply pipe 30). Are the same as in the first embodiment shown in FIG.

Next, the operation and effect of this embodiment having the above configuration will be described. According to the present embodiment, during normal operation, the on-off valve 19 of the communication pipe 18 is closed, and water supplied from the water supply inlet 2 is ejected from the injection nozzle 50 of the steam ejection unit 5 in the water storage 4. After being sufficiently heated and degassed by the heated steam, the water is sent from the water supply outlet 6 to the steam generator.

On the other hand, when the pressure in the deaerator tank 1 is reduced due to a change in the load of the steam turbine, the open / close valve 19 of the connecting pipe 18 is opened, so that the hot water supplied from the water supply outlet 6 to the water supply pipe 9 is heated. Is returned into the deaerator tank 1 from the connecting pipe 18 via the water supply inlet 2. The high-temperature feedwater returned to the deaerator tank 1 is flashed in the tank 1 to generate steam, and compensates for a decrease in pressure in the deaerator tank 1 to suppress a decrease in saturation temperature.

As a result, it is possible to prevent bubbles from increasing due to flushing in the water supplied in the vicinity of the water supply outlet 6, thereby preventing air bubbles from being mixed into the water supplied from the water supply outlet 6 to the steam generator. it can.

In FIG. 3, the connecting pipe 18 is
The connection pipe 18 is connected to the water supply inlet 2 via the condenser side water supply pipe 30. As shown in FIG. 4, the connection pipe 18 is directly connected to the deaerator tank 1 near the water supply inlet 2. May be.

[0051]

According to the present invention, when the pressure in the deaerator tank drops due to a change in the load of the steam turbine, it is possible to prevent an increase in air bubbles due to flushing in the water supply near the water supply outlet. It is possible to prevent air bubbles from being mixed in the water supplied from the outlet to the steam generator.

[Brief description of the drawings]

FIG. 1 is a structural diagram showing a first embodiment of a steam turbine deaerator according to the present invention in a vertical cross section of a deaerator tank.

FIG. 2 is a structural view showing a second embodiment of the steam turbine deaerator according to the present invention in a vertical cross section of a deaerator tank.

FIG. 3 is a structural diagram showing a third embodiment of a steam turbine deaerator according to the present invention in a vertical cross section of a deaerator tank.

FIG. 4 is a structural view showing a modification of the steam turbine deaerator shown in FIG.

FIG. 5 is a structural view showing one example of a conventional steam turbine deaerator in a vertical cross section of a deaerator tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Deaerator tank 2 Water supply inlet 2a Regular water supply inlet 2b Bypass water supply inlet 4 Water reservoir 5 Steam jetting part 6 Water supply outlet 6a Regular water supply outlet 6b Bypass water supply outlet 8 Water supply pump 9 Water supply pipes 14a, 14b, 17a, 17b, 19 On-off valve 18 Communication pipe 40 Internal pipe

Claims (6)

[Claims] 1. A deaerator for a steam turbine for deaeration of feed water to a steam generator, comprising: a horizontal deaerator tank having a water storage portion for storing water therein; and a water storage portion of the tank. A steam spouting section for spouting heated steam into the water supply in the tank, a water supply inlet section provided at the upper end of one end of the tank, and a water supply inlet section to take in water into the tank, and a steam supply section provided at the bottom of the tank. A plurality of water supply outlets having an on-off valve for sending out water to the generator, wherein the plurality of water supply outlets are a regular water supply outlet disposed on the other end side of the tank; and a regular water supply outlet. A deaerator for a steam turbine, comprising: one or more bypass water supply outlets disposed closer to one end of the tank than a part. 2. A deaerator for a steam turbine for deaeration of feed water to a steam generator, comprising: a horizontal deaerator tank having a water storage portion for storing water therein; and a water storage portion of the tank. A steam spouting section for spouting heated steam into the water supply at a plurality of water supply inlets provided at an upper portion of the tank and having an on-off valve for taking in water into the tank; and one end of the tank A water supply outlet provided at a bottom portion for sending out water to the steam generator; the plurality of water supply inlets including a service water supply inlet disposed at the other end of the tank; and a service water supply inlet provided at the other end of the tank. A deaerator for a steam turbine, comprising one or more bypass feed water inlets located closer to one end of the tank than the tank. 3. A deaerator for a steam turbine according to claim 2, wherein an opening / closing valve at said bypass feed water inlet is omitted. 4. The deaerator for a steam turbine according to claim 2, further comprising an internal pipe extending from the bypass water supply inlet to above the water supply outlet in the tank. 5. A deaerator for a steam turbine for deaeration of feed water to a steam generator, comprising: a deaerator tank having a water storage portion for storing water therein; and a water supply in the water storage portion of the tank. A steam jetting portion for jetting heated steam therein, a water feed inlet portion provided at an upper portion of the tank and for taking water into the tank, and a water feed outlet portion provided at a bottom portion of the tank. A water supply pipe connecting a water supply outlet and the steam generator, and a water supply pipe provided with a water supply pump interposed therebetween; the water supply pipe being branched from a downstream side of the water supply pump and connected to the water supply inlet through an on-off valve; A deaerator for a steam turbine, comprising: a communication pipe; 6. The deaerator for a steam turbine according to claim 5, wherein the communication pipe is directly connected to the tank near the water supply inlet.