JPS5971902A - Drain system of feedwater heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technology of the Invention Field 5] The present invention relates to a drain system for a feed water heater in a nuclear power plant.

[Technical background of the invention]

Conventionally, the feed water heater drain system of the Kame nuclear power plant was configured as shown in Figure 1.

Steam S generated in the nuclear reactor is controlled by a main steam stop valve (1) and a main steam control valve (2) and enters a high pressure turbine (3).

The exhaust steam that has done work in the high-pressure turbine (3) is transferred to the exhaust pipe (
4), after which moisture is removed by a moisture separator (5), it flows into a low pressure turbine (6). Usually 800 MW~
There are three low pressure turbines (6) in an 1100 MW class atomic coupler. Here, only one series of I100MW class atomic couplants will be described as a representative. The remaining two lines are indicated as second line A and third line/B in the figure. The exhaust gas of the low pressure turbine (6) is indirectly cooled in the condenser (7) and becomes condensate (8), which is extracted and pressurized by the pump (9).
The air extractor and the ground natural air condenser (iL condensate desalination equipment and filtration equipment A odor etc. are connected by a condensate pipe (II), and the water supply of the break installed at the top of the condenser (7) The condensate is sent to the heater 03).The condensate is sent to the feed water heater θ3),
(t(a), (15), (1G), (17
), the water is sequentially heated and sent to the water supply pump ([8)]. The condensate sent to the feed water pump (18) K is further boosted in pressure, passed through the water feed pipe (Iω), further heated by a high pressure feed water heater 0■, and sent to the reactor R.

Feed water heater α3), (+, 4), (I, G6
) and α'7) are the heating steam lines extracted from the intermediate stage or exhaust of the high-pressure turbine (3) and low-pressure turbine (6), that is, the extraction steam system (2υ, (221
, (23+ , H, (2, 00 by condensate (8)
heat up. The condensate is heated and condensed, and the extracted steam becomes 1/ton, drain piping (27), (2g), (2
9), (30), G31), 0 control valves,
(33), (34), G3 (to), (30) are sequentially sent to the low-pressure feed water heater and collected, and finally, through the drain pipe (37), control valve c38, and pump (3gJ). Collected into water container (A).

In addition, the moisture separated by the moisture separator (5) installed in the middle of the exhaust steam pipe of the high-pressure turbine (3) is collected and becomes a drain. It is collected in the heater a61.

[Problems with background technology]

In a nuclear power plant with such a system, as mentioned above, there are several stages of feedwater heaters, and most of the feedwater heaters are installed separately at a location away from the condenser. , the arrangement was such that only the lowest pressure feedwater heater was installed within the upper body of the condenser.

Condensate pipes and water supply pipes, each bleed steam line, each drain line, and numerous control valves are provided to connect these feed water heaters! l)-+e It is complicated.

On the other hand, as the feed water heater goes from high pressure to low pressure, the amount of drain and the flow rate of extracted steam increase, and accordingly, the diameter and size of the heating steam pipe, drain pipe, control valve, etc. become larger.

The space occupied by the Toreyoshi feed water heater, each piping, control valve, etc. occupies a large proportion of the plant construction space.
In particular, in 800 MW to I100 MW class atomic couplers, these several stages of feed water heaters can be used in as many as three series.
Space becomes more of an issue.

As described above, the installation space for each device and piping becomes larger, resulting in a larger building, leading to an increase in the construction period and the amount of work, resulting in a significant increase in construction costs.

In such systems, we aim to reduce plant construction costs, reduce piping, and improve reliability.
A method of housing multiple feedwater heaters in the upper part of the condenser has also been considered, but this approach has been limited.

[Purpose of the invention]

The present invention was made in order to eliminate the drawbacks of the above-mentioned prior art, and it avoids the increase in construction cost due to the enlargement of the building, and also connects the piping connecting the turbine and the feed water heater and the feed water heaters to each other. It is an object of the present invention to provide a drain system for a feed water heater, which can significantly reduce the length of piping for water supply, simplify the bleed steam system and the drain system, and improve reliability.

[Summary of the invention]

In order to achieve the above object, the present invention separates the drain cooling part of the feed water heater into a separate drain cooler, installs a plurality of low pressure feed water heaters in the upper body of the condenser, and
A drain tank was installed between the drain cooler and the feed water heater, which were placed separately, to collect the drain from the feed water heater, and then send this drain to the drain cooler to heat the condensate. It is characterized by the following.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. As shown in FIG. 2, condensate (8) condensed by force is extracted and pressurized by a pump (9) and sent to drain cooling 142'.

This drain cooler (6) is the last low pressure feed water heater α3.
5) The drain cooling part of 5) is replaced with a separate device, and thereby the external dimensions of the feed water heater 03 can be made much smaller than that of the conventional one. Therefore, the feed water heater a4), which conventionally had to be placed outside the condenser,
, (tr;) are also all installed in the upper body of the condenser as shown in FIG.

Drain cooler (4) Covered water that has passed through the drain is connected to the low-pressure feed water heater α3 installed inside the condenser body), (f4)
, α one.

(It passes through 10 in sequence and is gradually heated, water supply pump α8)
VtC water is supplied. The condensate water whose pressure is further increased by the feed water pump α barrel, the low pressure feed water heater (13) as well as the high pressure water supply power n heater ([7)] feed water heater (f7), (
20), the water is further heated and sent to the reactor H. Here, between the feed water heater αη and the drain cooler (4
(44) is provided.

By installing this tank (44) to collect the drain from the feed water heater, there is no need to store drain and create a water level in the feed water heater (17). As a result, even if the drain flow rate changes due to the plant output or the pressure inside the feed water heater αη changes, the drain is transferred to the next stage feed water heater (16) due to the positional head difference caused by the water level change (44). In addition, the drain of the moisture separator (5) is connected to tank 0 (a) with the drain pipe (40) to collect the drain.Even if this drain pipe (41 is connected to the tank (44), there is no drain). Piping (28) You may contact K.

The high-pressure feed water heater (20) and a7) are separated from the drain cooler (49) and provided with a drain tank (44), making them smaller than conventional technology, so in the conventional plant there were three series. By using two lines of feed water heaters, it is possible to keep the external dimensions to about the same as conventional plants.

This means that the space occupied by the feed water heaters in the conventional plant, which had three lines, will be reduced compared to the two lines.

In addition, the drain cooler (the drain passing through the 4th floor, controlled by the control valve (331) by the drain pipe c281, and the condenser (7)
) is sent to the next feed water heater aO installed at the top.

The condensate is likewise sent through a further feedwater heater (151) located above the condenser (low-pressure feedwater heater A4, which may be controlled by four control valves).

In addition, between the feed water heater (13) and the drain cooler (4), the tank (40) that collects the drain and the feed water heater (13) are connected through a pipe (47) to balance the pressure. Make it.

The drain that has passed through the feed water heater 04) is transferred to the drain pipe (48).
It is controlled by a control valve (offshore) and recovered into a tank (40).

On the other hand, the heated bleed steam (26) of the feed water heater αJ condenses and becomes drain and is discharged to the tank (46) through the drain pipe (41).This drain pipe (4) is connected to the tank (46). Alternatively, the drain pipe GQ from the tank may be connected in the middle.The drain collected in the tank (4G) in this way is passed through the drain pipes 50) and (51) to the drain cooler (4 side). is led to the condenser C power via.

According to the prior art, the lowest pressure feed water heater a~ installed at the top of the condenser (7) was very large because all the condensate was collected therein, but according to the present invention, Since the drain collected in the feed water heater a(a) located upstream thereof is sent to the tank (46) without passing through the feed water heater α3), it is possible to make it much smaller than in the prior art. Therefore, by providing sufficient space above the condenser (power), the low pressure feed water heater α mark (15), (
These feed water heaters (16), (15),
The extraction steam piping (23), c24), (25) from the low pressure turbine (6) that heats the steam turbine (14) is much shorter than in the prior art.

Furthermore, low pressure feed water heater α0. (1, 14),
Drain pipe connecting (13) 09), Cao),
(+8) also needs to be very short, reducing the space for these piping. Furthermore, since the condensate pipes similarly connect the feed water heaters installed nearby, they are short and require less space.

In the conventional technology, the feedwater heater Oa was installed at a relatively low position in the building, so the condensate was drained to the feedwater heater (I3) installed at the top of the condenser (I3) due to the pressure difference inside the feedwater heater. Unable to supply water, pump 0 due to pressure increase
However, according to the present invention, the feed water heater α power and the tank zero drain can be installed at a relatively high position in the building, so the internal pressure difference allows the drain to be sufficiently drained into the condenser ′ ( 7), water can be sent to the feed water heater (16) installed on top of the tank, eliminating the need for a pump to increase the pressure.

〔Effect of the invention〕

As described above, according to the present invention, the drain cooling part of the feed water heater is separated and placed separately, and a drain tank is provided to collect all the drain, thereby downsizing the feed water heater and obstructing the high-speed turbine exhaust flow. Since a plurality of feedwater heaters can be installed in the upper part of the condenser without having to do so, the bleed steam piping, drain piping, and condensate piping that connect the feedwater heaters are protected. Also, by eliminating the drain pressure pump, space for the pump becomes unnecessary. As a result, the building can be made smaller, the construction period can be shortened, the amount of work can be reduced, and reliability can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a drain system of a conventional feed water heater in a nuclear power plant, and FIG. 2 is a block diagram showing an embodiment of the present invention. 3... High pressure steam turbine, 6... Low pressure steam turbine, 7... Condenser, 8... Condensate, 13.1
4, 15, 16...Low pressure feed water heater, 19...
Water supply pump, 17.20... High pressure water supply heater, 27.
28, 29.30... Drain pipe, 42.43... Drain cooler, 44.46... Billet/tank.

Claims (2)

[Claims] (1) A plurality of low-pressure feed water heaters that heat the condensate of the steam turbine by extraction or exhaust, a feed pump that further increases the pressure of the heated condensate, and a feed water pump that further increases the pressure of the heated condensate; In a drain system of a feed water heater that includes a high pressure feed water heater that heats with exhaust air and a drain pipe that returns condensate condensed in these feed water heaters to a condenser, the drain cooling section of the feed water heater is The separated drain cooler is placed separately, the plurality of low-pressure feed water heaters are installed in the upper body of the condenser, and a drain tank is provided between the separate drain cooler and the feed water heater to supply water. A drain system for a feed water heater, characterized in that drain from the heater is collected. (2) A drain system for a feed water heater according to claim 1, wherein the drain collected in the drain tank is sent to the drain cooler to heat condensate.