JPH0910506A - Dehydration instrument - Google Patents

Abstract

PURPOSE: To provide a dehydration instrument for removing effectively scale such as magnetite out of steam conclensate flowed into the dehydration instrument. CONSTITUTION: This instrument is provided with a dehydration tank 1 and a water storage tank 11 in the lower section, and the insides of the dehydration tank 1 and the water storage tank 11 communicate with each other by three connecting tubes 12. The water storage tank 11 is formed into the cylindrical shape, and its axial center is disposed facing in the vertical direction. The three connecting tubes 12 are connected with the outer peripheral face of the water storage tank 11 in the tangential direction. The inlet of a downcomer 13 is opened along the axial center of the water storage tank 11 with the sufficient separating distance to a bottom section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deaerator used in a water supply system of a power plant.

[0002]

2. Description of the Related Art As shown in FIG. 10, a deaerator used in a water supply system of a power plant is composed of an upper deaeration tank 1 and a lower water storage tank 2. Dissolved oxygen is removed by heating steam, and this degassed condensate is stored in the lower water storage tank 2 as feed water. The water supply system incorporating this deaerator is connected to the boiler, and the water supply extracted from the water storage tank 2 is pressurized by the boiler water supply pump and supplied to the boiler via the high-pressure water supply heater.

[0003]

By the way, the drain from the high-pressure feed water heater is flowing into the water storage tank 2 together with the degassed condensate, and the condensate and the condensate are discharged when the plant is operated for a certain period of time. It is known that scale such as magnetite mixed in the drain is easily accumulated in the water storage tank 2. Such scales mix with the feed water and flow into the high-pressure feed water heater and the boiler of the feed water system, and adhere to the inner surfaces of the heat transfer tubes, which reduces the flow passage area of the heat transfer tubes. Therefore, the resistance when pushing the feed water into the heat transfer tube increases, the power for driving the boiler feed water pump gradually increases due to the accumulation of scale, and the efficiency of the entire plant decreases.

Further, if a large amount of this scale is deposited on the impeller of the water supply pump, the efficiency of the pump is lowered and, in some cases, the operation of the plant is hindered by the vibration of the impeller.

Therefore, an object of the present invention is to provide a deaerator capable of effectively removing scale such as magnetite from the condensate flowing into the deaerator.

[0006]

SUMMARY OF THE INVENTION The present invention comprises a cylindrical water storage tank, the water storage tank is provided below the deaeration tank so as to maintain an axial center in the vertical direction, and an inlet is provided in the water storage tank. In a deaerator in which a downcomer pipe is connected and the deaeration tank and the water storage tank are connected to each other by a communication pipe, a plurality of the communication pipes have outlets directed tangentially to the water storage tank. It is characterized in that they are respectively connected to the cylindrical outer peripheral surface.

Another aspect of the invention is to provide a water storage tank comprising a cylindrical body and an end plate having a spherical surface for sealing both ends of the body, the water storage tank being horizontally below the deaeration tank. The barrel is provided so as to maintain the axial center of the barrel, and a downcomer pipe is connected to the barrel with its inlet facing, and the storage tank and the water storage tank are communicated with each other by a connecting pipe having a plurality of outlets. In the deaerator configured as described above, a plurality of outlets of the connecting pipe are arranged so as to be inclined at a predetermined angle with respect to the axis of the barrel in the direction of the end plate.

[0008]

According to the present invention, the condensate is made to flow as a swirl flow to effectively separate the scales in the water storage tank, and the scale having a larger specific gravity than water is separated by centrifugal force. The outlets are connected tangentially to the cylindrical outer peripheral surface of the water storage tank. Condensate flowing into the vessel from the outlet of each connecting pipe flows while swirling in the circumferential direction along the inner peripheral surface of the water storage tank.At this time, a heavy scale is transported to the vicinity of the inner peripheral surface by centrifugal force, and the condensate is condensed. Separated from the water and gather at the bottom near the inner surface of the water tank. By separating the scale in this way, it is possible to prevent the scale from adhering to the inner surfaces of the high-pressure feed water heater of the feed water system and the heat transfer tube of the boiler. As a method of forming a swirl flow, it is desirable to use a water storage tank that keeps the axis in the vertical direction, but it is possible to form the swirl flow with a spherical end plate even in the case where the axis is kept in the horizontal direction. is there. That is, in another invention, a plurality of outlets of the connecting pipe are arranged at a predetermined angle with respect to the axis of the barrel in the direction of the end plate formed on the spherical surface. By arranging in this way, the condensate flowing into the vessel flows while swirling along the spherical surface of each end plate, and the heavy scale is brought near the spherical surface by centrifugal force and separated from the condensate. Thus, also in this other invention, it is possible to prevent the scale from adhering to the inner surfaces of the high-pressure feed water heater and the heat transfer tube of the boiler.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the deaerator is an upper deaerator 1
And a lower water storage tank 11, and the deaeration tank 1 and the water storage tank 11 are connected to each other by three connecting pipes 12. The water storage tank 11 is formed in a cylindrical shape, and is arranged with its axis centered in the vertical direction. The outlets of the three connecting pipes 12 are connected to the outer peripheral surface of the water storage tank 11 so as to face in a tangential direction. Also, the water storage tank 11
A downcomer 13 is connected to the bottom of the. This downcomer 1
The inlet of 3 is opened along the axis of the water storage tank 11 with a sufficient distance from the bottom.

Next, the operation of the deaerator having the above structure will be described.

Condensate from the degassing tank 1 is connected to the connecting pipe 12 respectively.
And flows into the water storage tank 11. At this time, the condensate flows from the outlet opening in the tangential direction while swirling in the circumferential direction of the water storage tank 11. The formation of this swirling flow causes a scale heavier than the water contained in the condensate to flow along the inner peripheral surface of the water storage tank 11 due to centrifugal force,
Most are gathered at the bottom near the inner surface. That is, the scale can be separated from the condensate flowing into the water storage tank 11. On the other hand, since the inlet of the downcomer pipe 13 is opened with keeping a distance from the bottom of the water storage tank 11, when the water supply from the water storage tank 11 flows out, the water from the thinnest water supply on the scale close to the surface of the water is supplied to the downfall pipe 13. Can lead to the entrance.
Since the feedwater with the smallest scale flows from the high-pressure feedwater heater to the boiler, a large amount of scale can be prevented from accumulating on the inner surface of each heat transfer tube. Further, it becomes possible to prevent the scale from accumulating on the impeller of the boiler feed pump. The water tank 1
The scale collected at the bottom of 1 is discharged from a drain port (not shown) when the plant is stopped.

Another embodiment of the present invention will be described with reference to FIG. The basic part of the water storage tank 11 of this embodiment is the same as that of the above embodiment. The water storage tank 11 of this embodiment is provided with three flat screens 14 made of electromagnets extending from the inner peripheral surface to the center in the radial direction. Each of the three screens 14 has its front facing the outlet of each connecting pipe 12, and is arranged at a position sufficient for capturing the scale in the condensate.

In the deaerator having the above structure, when condensate flows while swirling inside the water storage tank 11, the scale and the like contained in the condensate are captured by the screen 14 where magnetic force is constantly acting, and only the condensate is collected. Go through there.
While the electromagnet is functioning, the movement of the scale or the like is restricted by the screen 14, so that the scale is not mixed again in the condensate and the scale can be effectively separated.

Therefore, when the feed water flows out from the water storage tank 11, it is possible to guide the feed water having almost no scale to the inlet of the downcomer pipe 13, and a large amount of water is supplied to the inner surfaces of the high-pressure feed water heater of the water feed system and the boiler. It becomes possible to prevent the scale from accumulating. When the plant is stopped and the deaerator is cleaned, the scale accumulated on the screen 14 is removed by turning off the power of the electromagnet.

Further, a screen of a permanent magnet may be used instead of the screen 14 made of the electromagnet described in this embodiment.

Further, another embodiment of the present invention will be described with reference to FIG.

In this embodiment, as shown in the figure, the water storage tank 11
A rod-shaped capture member 15 made of an electromagnet is provided along the inner peripheral surface of the. The catching member 15 is formed to have a length substantially the same as the depth of the water storage tank 11.

In the deaerator having the above-mentioned structure, when the condensate flows inside the water storage tank 11 while swirling along the inner peripheral surface, the scale or the like in the condensate is captured by the capture member 15 in which magnetic force is constantly acting. It Since the scale is restrained by the capture member 15, even if the condensate flows inside the water storage tank 11, it does not mix again in the condensate and the scale can be sufficiently separated.

Therefore, also in the present invention, the condensate pipe 13
It is possible to introduce a feedwater having almost no scale to the inlet of, and to prevent a large amount of scale from being deposited on the inner surfaces of the heat transfer tubes of the feedwater high-pressure feedwater heater and the boiler.

In this embodiment, instead of using the electromagnet to actuate the trapping member 15, a trapping member made of a permanent magnet may be used.

Further, a different embodiment is shown in FIGS.
This will be described with reference to FIG.

As shown in FIG. 4 (a), the water storage tank 11 is provided with an annular trapping member 16 made of an electromagnet along the inner peripheral surface thereof. As shown in FIG. 4B, the capturing members 16 are arranged in a plurality of rows in the depth direction of the water storage tank 11 (4 in the embodiment).
Columns).

The function of the trapping member 16 in this embodiment is the same as that of the trapping member 15 described above, and the scale can be sufficiently separated. It should be noted that instead of the capturing member 16 made of an electromagnet, a capturing member made of a permanent magnet may be used.

Furthermore, a different embodiment is shown in FIGS.
This will be described with reference to FIG.

As shown in FIG. 5A, the water storage tank 11 has an annular screen 17 formed of an electromagnet along the inner peripheral surface thereof.
Is provided. As shown in FIG. 5B, the screen 17 is arranged at a slight distance from the inner peripheral surface of the water storage tank 11.

Condensed water is also stored in the water storage tank 11 in this embodiment.
When flowing while swirling through the inside along the inner peripheral surface, the scale or the like in the condensate is captured by the screen 17 where the magnetic force is constantly acting. Therefore, the scale can be sufficiently separated, and it is possible to guide the water with almost no scale to the inlet of the downcomer pipe 13 as in the above-described embodiments. Further, a different embodiment will be described with reference to FIG.

In this embodiment, a water supply recirculation pipe is further provided in the embodiment shown in FIG. This water recirculation pipe 18
Connects between the downcomer pipe 13 and the degassing tank 1, and a recirculation pump 19 is provided in this path.

For example, the recirculation pump 19 is operated for a certain period of time when the plant having a relatively high scale concentration is started to guide the water supply in the water storage tank 11 to the degassing tank 1 through the water supply recirculation pipe 18 and again to the water storage tank 11. To return to. By starting the water supply to the high-pressure water heater of the water supply system after reducing the scale concentration through such an operating method, it becomes possible to maintain the scale separation effect higher.

Further, another embodiment will be described with reference to FIG. As shown in FIG. 7A, the water storage tank 20 of this embodiment is composed of a horizontally long cylindrical body 21 and an end plate 22 having a spherical surface that seals both ends of the body 21. A connecting pipe 23 having two outlets is provided so as to face the body 21 of the water storage tank 20, and the respective outlets are in the direction of the end plate 22 as shown in FIG. It is tilted by a predetermined angle. In addition, a downcomer 24 having two inlets is connected to the lower part of the body 21,
The inlets are opened near the end plate 22 and near the water surface of the water storage tank 20, respectively.

In the deaerator having the above structure, the condensed water from the deaerating tank 1 flows into the water storage tank 20 through the connecting pipe 23. The two outlets of the connecting pipe 23 are inclined in the direction of the end plate 22 with respect to the axis of the barrel 21, and the condensate that has flowed into the water storage tank 20 flows spirally along the spherical surface of the end plate 22. At this time, the scale having a larger specific gravity than water flows along the spherical surface of the end plate 22 due to the centrifugal force and gathers at the bottom of the water storage tank 20. On the other hand, the inlet of the downcomer 24 opens near the center of the spiral flow, near the water surface sufficiently far from the bottom, and this position is the thinnest part of the scale. , The water supply with the smallest scale can be led to the inlet of the downcomer 24.

Therefore, it becomes possible to prevent a large amount of scale from accumulating on the inner surface of each heat transfer tube by causing the feed water with a small scale to flow further from the high pressure feed water heater to the boiler.

Although this embodiment uses an electromagnet, it may be replaced by a screen made of a permanent magnet.

Further, another embodiment is shown in FIGS. 8 (a) and 8 (b).
This will be described with reference to FIG. As shown in FIG. 8A, the water storage tank 20 is composed of a horizontally long cylindrical body 21 and an end plate 22 having a spherical surface that seals both ends of the body 21. 7). Connecting pipe 23 with two outlets and downcomer 24 with two inlets
It is also the same as the above-mentioned embodiment to provide the inside of the body 21 of the water storage tank 20. In this embodiment, two flat screens 25 made of electromagnets are further provided in the body 21.
As shown in FIG. 8B, the screen 25 is provided so that its front surface faces the condensate flowing in the water storage tank 20 along the end plate 22 and faces the substantially hemispherical surface of the end plate 22, respectively.

In the deaerator having the above structure, when the condensate flowing out from the outlet of the connecting pipe 23 flows spirally along the inner surface of each end plate 22, the scale having a larger specific gravity than the water is applied to the end plate by centrifugal force. It flows along the spherical surface of 22. When the scale reaches the screen 25 arranged so as to face the substantially hemispherical surface of the end plate 22 and face the condensed water,
Only scale is captured by screen 25 and condensate passes through screen 25. The screen 25 is composed of an electromagnet, and while it functions as a magnet, the movement of the attached scale is restricted, so that it does not mix again in the condensate.

Therefore, also in the present embodiment, when the feed water flows out, it is possible to guide the feed water having almost no scale to the inlet of the downcomer pipe 24, and a large amount of water is supplied to the inner surfaces of the heat transfer pipes of the high-pressure feed water heater of the water feed system and the boiler. It is possible to prevent the scale from being deposited. Further, a different embodiment will be described with reference to FIG. Also in this embodiment, two screens 26 made of electromagnets are used. It is the same as in the above embodiment (FIG. 8) that the screen 26 faces the condensate flowing in the water storage tank 20 along the end plate 22, but as shown in FIG.
It is provided so as to face the entire spherical surface of the end plate 22 in the direction crossing 1.

The function of the screen 26 of this embodiment is similar to that of the screen 25 of the above-mentioned embodiment (FIG. 8), and the scale can be sufficiently separated. Therefore,
Also in the present embodiment, it is possible to introduce a small-scale water supply to the inlet of the downcomer pipe 24. Note that this embodiment can also be configured by a screen made of a permanent magnet instead of the electromagnet screen 26.

[0038]

As described above, according to the present invention, a water storage tank is provided below the deaeration tank while keeping an axis in the vertical direction, and a plurality of connecting pipes are connected to each other so that each outlet is directed tangentially. In another invention, a water storage tank is provided below the deaeration tank while keeping the axis of the cylinder horizontally, and a plurality of outlets of the connecting pipe are connected to the end plate toward the axis of the cylinder. On the other hand, the scale is separated from the condensate flowing while swirling in the water storage tank because the scale is tilted by a predetermined angle and connected to the case. Therefore, according to the present invention, it is possible to prevent a large amount of scale from adhering to the inner surface of the heat transfer tube of a boiler or the like and impairing the efficiency of the entire plant.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a deaerator according to the present invention.

FIG. 2 is a configuration diagram showing another embodiment of the present invention.

FIG. 3 is a configuration diagram showing another embodiment of the present invention.

FIG. 4 is a configuration diagram showing another embodiment of the present invention.

FIG. 5 is a configuration diagram showing another embodiment of the present invention.

FIG. 6 is a configuration diagram showing another embodiment of the present invention.

FIG. 7 is a configuration diagram showing another embodiment of the present invention.

FIG. 8 is a configuration diagram showing another embodiment of the present invention.

FIG. 9 is a configuration diagram showing another embodiment of the present invention.

FIG. 10 is a configuration diagram showing an example of a conventional deaerator.

[Explanation of symbols]

 1 Deaeration tank 11, 20 Water storage tank 12, 23 Communication pipe 13, 24 Precipitation pipe 14, 17, 25, 26 Screen 21 Body 22 End plate

Claims (8)

[Claims] 1. A water storage tank having a cylindrical shape is provided, the water storage tank is provided below the deaeration tank so as to maintain an axial center in a vertical direction, and a downcomer pipe is connected to the water storage tank with its inlet facing. A deaerator in which the deaeration tank and the water storage tank are connected to each other by a communication pipe, wherein each outlet of the plurality of communication pipes is directed tangentially to a cylindrical outer peripheral surface of the water storage tank. A deaerator characterized by being connected. 2. A trapping means for trapping scale contained in condensate is provided in a region of the water storage tank facing each outlet of the connecting pipe or on an inner peripheral surface of the water storage tank. The deaerator according to claim 1. 3. The deaerator according to claim 2, wherein the trapping means is a flat or annular screen composed of a magnet. 4. The deaerator according to claim 2, wherein the trapping means comprises a rod-shaped or annular trapping member composed of a magnet. 5. A water storage tank comprising a cylindrical body and an end plate having spherical surfaces for sealing both ends of the body, the water storage tank being located below the deaeration tank in a horizontal direction. The degassing is made by connecting the downcomer pipe with the inlet facing the inside of the barrel and connecting the depletion tank and the water storage tank with each other by a connecting pipe having a plurality of outlets. A deaerator, wherein a plurality of outlets of the connecting pipe are arranged so as to be inclined at a predetermined angle with respect to the axis of the body in the direction of the end plate. 6. A catching means for catching the scale contained in the condensate is provided in a region which faces the condensate flowing along the end plate in the water storage tank and faces the substantially half surface or the whole area of the end plate. The deaerator according to claim 5, which is characterized in that. 7. The deaerator according to claim 6, wherein the capturing means is a flat screen composed of a magnet. 8. The deaerator according to claim 1, wherein the downcomer is connected with an opening facing a surface of water sufficiently far from the bottom of the water storage tank.