JPS6338804A - Condensate device - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to condensation equipment for nuclear power plants, etc., and in particular, it circulates condensate in order to reduce the occurrence of rust when the plant is stopped, and also This invention relates to a condensing device suitable for removing highly concentrated waste contained in water in a short time and recovering it as water for reuse in a plant.

[Conventional technology]

In condensation equipment such as conventional nuclear power plants.

As stated in Japanese Patent Publication No. 60-15209,
Since the condensate in the condenser hotwell was collected in the condensate recovery tank, in order to secure the required flow rate, the installation level difference between the condenser and the condensate recovery tank was large and the hydrostatic head was secured. I needed to.

However, in order to ensure the installation level difference (static head) between the condenser and condensate recovery tank, it is necessary to raise the condenser installation level or lower the condensate recovery rate. This requires a large amount of money.

In addition, even though the above-mentioned static water head cannot be secured, even if the above-mentioned device is installed, the amount of condensate to be recovered will be small, and as a result, the original purpose of condensate being transferred to the condensate storage tank will be reduced. The effect of shortening collection time is reduced.

In addition, for other purposes, such as supplying water from the condensate recovery tank to the condensate purification device by the condensate recovery pump, performing condensate circulation storage operation of the condensate water supply system, and suppressing the occurrence of rust in the system. Also, since the condensate circulation flow rate decreases, the rust prevention effect also decreases.

In addition, since conventional equipment does not have a function to control the condensate flow rate to one point, when the amount of condensate flowing into the condensate recovery tank increases, the condensate recovery pump enters runout operation, resulting in an overflow that roughly exceeds the pump performance. If the flow rate is too high, there is a possibility that the pump will be destroyed.Also, it does not have the function to adjust the condensate flow rate.

Differences in system loss due to differences in operation modes, and differences in system loss due to errors between the design value and the actual value of system loss.

Alternatively, it is not possible to absorb fluctuations in condensate flow rate due to changes in system loss due to increases in pipe inner surface roughness due to aging.

Therefore, as described above, if the condensate flow rate is small, the effect of installing the device will be reduced, and on the other hand, if the condensate flow rate is excessive, the pump and motor may be destroyed.

Here, the conventional condensing device will be explained in more detail with reference to FIGS. 3 and 4, taking a nuclear power plant as an example.

Steam in nuclear power plants. The condensate water supply system is constructed at the bottom as shown in Figure 3.During plant operation,
Steam generated in the nuclear reactor 1 is expanded in the turbine 2 to perform work, and then cooled in the condenser 3 to become condensed water.

This condensate is sucked out by a condensate pump 4 and introduced into a condensate purification device 6 via a condensate pipe 5. Here, impurities in the condensate (
After removing Fe, Nl, Co, radioactive materials, etc.), the pressure is increased by the condensate booster pump 7, then heated and heated by 8 feed water heaters, the pressure is increased by the feed water pump 9, and then the feed water heater After being heated at 8B, water supply pipe 1
0, forming a closed circuit that returns to the reactor l.

In this closed circuit, the flow balance is disrupted and the condenser 3
When the water level reaches a high level, the valve 30 is opened and the condensate is discharged to the condensate storage tank 12 via the spillover pipe 11.

In addition, the shaft seal of the water supply pump 9 is of the water seal type in the case of 800 MWe class or higher, and is used as a condensate booster pump.

Seal water is supplied to the water supply pump 9 through a seal water supply pipe 13 branched from the discharge pipe 7. The sealed water is collected into the condensate recovery tank 15 via the sealed water return pipe 14.

In addition to this sealed water return water, the condensate recovery tank 15 contains:
Some drains have been recovered. The recovered condensate is pressurized by the condensate recovery pump 16 and is recovered to the condenser 3 via the condensate recovery tank water level adjustment valve 242 and the condensate recovery pump discharge pipe 17.

During normal operation, the route is as described above.

On the other hand, in order to reduce % corrosion products during plant shutdowns, especially during long-term shutdowns such as periodic inspections.

Operation experiments have confirmed that it is effective to operate the condensate and water supply systems in circulation storage operation at low flow rates. The circulation storage operation route during stoppage will be explained.

The valve 26 provided in the condensate recovery pump discharge pipe 17 shown in FIG. is the input. The opening degree is adjusted by the level regulator 33, and it operates as a water level adjustment valve that adjusts the liquid level of the condensate recovery tank 15.

27 is a level switch for controlling the condensate recovery pump 16, and 28.29 is a level transmitter and level regulator for controlling the water level adjustment valve 24 that adjusts the water level of the condensate recovery tank 15 during normal operation. .

In this configuration, the flow of condensate during circulation storage operation will first be explained.

During circulation storage operation, the water level adjustment valve 24. A valve 30 provided in the spillover pipe 11. While the valve 34 of the water sealing supply pipe 13 is closed, the water level I control valve 26. Condenser drain valve 31, 4
1 Open the bypass valve 25% water boost pump bypass valve 351 of the water boost pump bypass f18 and the valve 36 of the condensate water recirculation pipe 20.

The condensate recovery pump 16 is operated to circulate the condensate. Therefore, the drain in the condenser 3 at this time is recovered into the condensate recovery tank 15 via the condenser drain pipe 22. The recovered condensate is sucked out by the condensate recovery pump 16 and introduced into the condensate purification device 6 via the discharge pipe 17% and the condensate communication pipe 23.

The condensate purified by the condensate purification device 6 is passed through the condensate boost pump bypass pipe 18. Feed water heater 8, water pump bypass pipe 1
9. and returns to the condenser 3 via the condensate feedwater recirculation pipe 20.

In this case, the liquid level in the condensate recovery tank 15 is detected by the level transmitter 32, and the level a! 4 by adjusting the opening degree of the water level control valve 26 with the regulator 33.

It is maintained at the set level. During this circulating storage operation, there is no need to seal the water pump 9, so the capacity of the condensate recovery pump 16 is calculated from the amount required during normal operation (water seal return, etc.). With the same capacity as
Sufficient capacity during circulation is also ensured.

Next, equipment drain recovery from the condenser 3 will be explained.

When recovering the condenser condensate, the water level adjustment valve 24, which is operated during normal operation, is used. and the bypass valve 25 of the condensate booster pop bypass pipe 18 are closed, while the drain valve 31 of the condenser drain pipe 22 and the water level control valve 2 of the condensate communication pipe 23 are closed.
61 and the spillover valve 30 of the spillover pipe 11 are opened, and the condensate is recovered while operating the condensate recovery pump 16.

In this case, the drain in the condenser 3 enters the condensate recovery tank 15 via the condenser drain pipe 22, and then passes through the condensate recovery pump discharge pipe 17 and the condensate communication pipe 23 to the condensate purification device. 6
After being purified, it is collected in a condensate storage tank 12 via a spillover pipe 11.

The water level in the condensate recovery tank 15 is adjusted by the water level adjustment valve 24 during normal operation, as described above.

The water level adjustment valve 26 is used during the condenser drain recovery and circulation operation. When the condenser drain is completely drained during condenser drain recovery, the level switch 27 is activated and the condensate recovery pump 16 is automatically tripped.

[Problem that the invention seeks to solve]

Here, the problems of the conventional technology will be explained with reference to Figures 5 and 6. ◎ During long-term shutdowns such as periodic inspections during plant shutdowns, the inside of the condenser 3 is at atmospheric pressure. . On the other hand, since the "01 water recovery tank 15 is at atmospheric pressure regardless of whether the plant is in operation or stopped, the condensate in the condenser 3 is...

Due to only the static head difference between the condenser 3 and the condensate recovery tank 15,
The condensate is collected into the condensate recovery tank 15 via the condensate pump suction pipe 21g and the condenser drain pipe 22.

The relationship between the static water head difference and the condensate flow rate is shown in FIG.

The condensate flow rate Q flowing through the condenser drain pipe 22 causes a pressure loss ΔP in its path, and the following relationship generally holds between Q and ΔP: ΔP−−Q2 (k is a constant). Since both the condenser 3 and the condensate recovery tank 15 are placed at atmospheric pressure, condensate flows only due to the static head H. Therefore, if dynamic pressure is ignored, the static head H and pressure loss The following relationship holds true between ΔP. Therefore, the static head H and the condensate flow rate Q
The relationship is H-kQ'', that is, the condensate flow rate Q increases or decreases according to the static water head H.

To explain these values in more detail using the 1100 MWe class atomic couplet as an example, based on the results of the existing platform.

Hydrostatic head J -2m.

Condensate flow rate (It -150ffl'/H) However, in a newly planned plant, the hydrostatic head h2 will be reduced to 1 m due to layout restrictions, so the condensate flow rate q!
is 100 d/H, which is two-thirds of the actual result.

In addition, the hydrostatic head H is as follows in the above-mentioned circulation storage operation.

Although it is constant unless there is condensate coming from outside the system, during the recovery operation of the condenser internal drain, the condensate in the condenser 3 is recovered to the condensate storage tank 12. The hydrostatic head H decreases with the outflow of condensate.

As is clear, a reduction in the hydrostatic head H affects and reduces the condensate flow fQ. Therefore, a decrease in the hydrostatic head H increases the time required to complete the recovery operation of the condensate in the condenser, resulting in a delay in the work process of periodic plant inspections.

As mentioned above, the conventional technology does not take into account the reduction in the condensate flow rate and the increase in the operation time for recovery of the condensate in the condensate pipe when the required value of the static head H cannot be secured. Other problems are discussed below.

The condensate in the condenser 3 is collected in the condensate recovery tank 15 via the condensate drain pipe 22, and the pressure is increased by the condensate recovery pump 16 and sent to the condensate purification device 6 via the condensate connection #23. As mentioned above, water is sent to

In this case, since the valve 26 provided in the condensate connecting pipe 23 adjusts the water level of the condensate recovery tank 15, the same flow rate of condensate flows into the condenser drain pipe 22 and the condensate connecting pipe 23. By the way, since the conventional condensate device does not have a function to adjust the flow rate of condensate flowing through the condensate drain pipe 22, it also does not have a function to adjust the discharge amount of the condensate recovery pump 16. . As mentioned above, the condensate flow rate Q of the condenser drain pipe 22 is
There are factors that easily vary due to hydrostatic head H and pressure loss ΔP.

According to the actual plant plan, the water level in the condenser 3 is expected to fluctuate by 0.5 m, and the water level in the condensate recovery tank 15 is expected to fluctuate by 0.2 m, depending on the plant operating conditions.
is considered to fluctuate by 0.7 m, which is equal to their sum.

Also, since the surface roughness inside the condenser drain pipe 22 changes depending on the operating age of the plant, the pressure loss ΔP will vary even if the condensate flow rate is the same.The fluctuations in the hydrostatic head H and pressure loss ΔP will , since the condensate flow rate Q is changed, the discharge amount of the condensate recovery pump 16 is also changed.

The discharge amount may exceed the specifications of the condensate recovery pump 16, causing equipment deterioration due to pump run-out operation, and furthermore, if an excessive amount of condensate flows, the pump may be destroyed. The fluctuation in pressure loss ΔP does not only apply to the condenser drain pipe 22 (it applies to all pipes in the system in each of the circulation storage operation and the condenser condensate recovery operation, and the variation in the condensate flow rate It brings about change.

As mentioned above, in the conventional technology, the condensate flow rate is 11!
The purpose of the present invention is to provide a suitable operation function even when the required amount of static water head cannot be secured, and also to make it possible to adjust the condensate flow rate, thereby improving the reliability of the plant. The object of the present invention is to provide a condensing device that can improve the performance.

[Means for solving problems]

The above purpose is to connect the condenser drain pipe directly to the suction pipe of the condensate recovery pump, and to adjust the water level control valve provided on the condensate communication pipe to the flow rate during circulation storage operation and condenser drain recovery operation. This is achieved by providing a flow rate transmitter for detecting the condensate flow rate in the condensate communication pipe to be used as a control valve, and providing a flow rate adjustment means for adjusting the opening degree of the flow rate control valve based on the output of the flow rate transmitter. Ru.

[Effect]

By directly connecting the condenser drain pipe to the condensate recovery pump suction pipe, condensate is transferred from the condenser to the condensate storage tank using not only the hydrostatic head of both, but also the suction of the condensate recovery pump. Therefore, even if the required hydrostatic head cannot be secured due to layout restrictions, etc., it is possible to prevent a decrease in the condensate flow rate.

Also, a flow rate control valve should be installed in the condensate connection pipe.

Even when the system pressure changes due to fluctuations in operating mode, disturbances, and pressure loss, the condensate flow rate remains constant.
[Example], which is useful for improving the reliability of the device and equipment, is described in Fig. 1 and Fig. 2.

In FIG. 1, the connection of the condenser drain pipe 22 and condensate communication pipe 23 is changed from the conventional connection method shown in FIG. 3.

That is, the piping 22 is connected to the condensate recovery tank 15 from the condensate suction pipe 21 in FIG.
In the figure, it is connected between the condensate suction pipe 21 and the condensate recovery pump suction pipe 37.

In addition, the condensate communication pipe 23 is branched from the condensate recovery pump discharge pipe 17 on the outlet side of the water level control valve 24 in FIG. 1, and the water level control valve 26 in FIG. 3 has been removed.

40.41 is the condensate recovery pump discharge valve and condensate communication valve provided in the pipe 17.23, and 39 is the condensate communication pipe 2.
This is a flow rate transmitter provided at 3.

The level switch 27 was provided in the condensate recovery tank 15 in the fourth section, but in FIG.

It is provided in the condensate pump suction main pipe 42 which is a part of the condensate pump suction pipe 21 .

During normal operation, the valve 24 provided on the condensate recovery pump discharge pipe 17 receives the output of the level transmitter 28 that detects the liquid level in the condensate recovery tank 15.
The fAWJ device 29 is adjusted upward by 29 degrees and is operated as a water level control valve that adjusts the liquid level of the condensate recovery tank 15 to n levels.

However, during condensate circulation storage operation or condenser water draining operation, the opening degree of the valve 24 is controlled by the flow rate regulator 44 which inputs the output of the flow rate transmitter 39 that detects the condensate flow rate of the condensate communication pipe 23. The condensate flow rate of the condensate communication pipe 23 is regulated and operated as a control valve.

That is, the signal switch 43 selects either the output from the water level regulator 29 or the output from the flow regulator 44, and the opening degree of the regulating valve 24 is controlled accordingly. Also, during condenser water drain operation.

Level switch 27 provided on the condensate suction main pipe 42
As a result, completion of water removal is detected and the condensate recovery pump 16 is stopped.

In this configuration, the flow of condensate in the condensate circulation storage operation will first be explained.

During condensate circulation storage operation, the discharge valve 40 provided in the condensate recovery pump discharge pipe 17. Spillover valve 30 provided in spillover pipe 11. Water sealing supply valve 3 of water sealing supply pipe 13
4 and the outlet valve 38 provided on the condensate recovery pump suction pipe 37 are closed, while the condensate drain valve 31 and the condensate communication valve 41 . The condensate booster pump bypass valve 25% water supply pump bypass valve 35 and the valve 36 of the condensate feedwater recirculation pipe 20 are opened, and the condensate recovery pump 168 is operated to circulate condensate.

Therefore, the drain in the condenser 3 at this time is sent from the condensate pump suction pipe 21 to the condensate recovery pump suction pipe 37 via the condensate drain pipe 22. The pressure is increased by the pump 16 and introduced from the condensate recovery pump discharge pipe 17 to the condensate purification device 6 via the condensate communication pipe 23,
The purified condensate is transferred to the condensate booster pump bypass pipe 18, the feed water heater 8, the feed water pump bypass pipe 19. Returns to condenser 3 via condensate feed water recirculation pipe 20.

In this case, the condensate flow rate is detected by the flow rate transmitter 39, and the detected output is supplied to the flow rate regulator 44, and the signal switch 43 is configured to select the output of the flow rate regulator. The set flow rate is maintained by adjusting the opening degree of the control valve 24.

During the above-mentioned condensate circulation storage operation, there is no need to seal the water supply pump 9, so the capacity of the condensate recovery pump 16 remains the same as the capacity calculated from the required amount (water return, etc.) during normal operation. , Sufficient capacity during circulation is ensured.

In addition, during this condensate circulation storage operation, the condensate recovery tank 1
5 will be separated by closing its outlet valve 38, but since the plant is stopped and there will be no return water from the water supply pump or other equipment drains, this is normally the case. There is no need to monitor water levels.

Next, the flow of condensate during drain recovery operation of the condenser 3 will be explained.◎ During the condenser drain recovery operation, the condensate recovery pump discharge pipe 17
The discharge valve 40 and condensate recovery pump suction pipe 3 provided in
While the condensate recovery tank river mouth valve 38 provided at the condensate recovery tank 41.7 is closed, the condensate communication valve 41. The spillover valve 30 and the condenser drain valve 31 are opened, the condensate recovery pump 16 is operated, and the condensate in the condenser 3 is recovered to the condensate storage tank 12.

Therefore, the drain in the condenser 3 at this time is sent to the condensate recovery pump suction pipe 37 via the condensate pump suction pipe 21 and the condenser drain pipe 22, and is boosted in pressure by the condensate recovery pump 16. The condensate is introduced into the condensate purification device 6 via the condensate recovery pump discharge pipe 17 and the condensate connection pipe 23, and after being purified there, is recovered into the AI water storage tank 12 via the spillover pipe 11. Even during operation, the condensate flow rate is detected by the flow rate transmitter 39 and maintained at the set flow rate by the %J control valve 24. In addition, when the condenser drain is completely drained during the condenser drain recovery operation, the level switch 27 provided on the condensate pump suction main pipe 42 is activated, and the condensate recovery pump 16 is activated.
trip automatically.

In the above-mentioned embodiment, the valve 24, which operates as the water level control valve of the condensate recovery tank 15 during normal operation, is switched to the flow fk1 regulating valve during the condensate circulation storage operation or the condenser drain recovery operation, Although the signal switch 43 is provided, the present invention can also be implemented as shown in FIG.

That is, as shown in FIG. M7, first, in the prior art shown in FIGS. 3 and 4, the condenser drain 122 is connected to the condensate recovery pump suction pipe 37, as in the previous embodiment. The control valve 24 provided in the condensate recovery pop discharge pipe 17 is used exclusively for adjusting the water level of the condensate recovery tank 15, while the control valve 26 provided in the % condensate water connection pipe 23 is used exclusively for adjusting the condensate flow rate.

For this purpose, the level transmitter 32 and level regulator 33 shown in FIG. A flow regulator 48 is provided to adjust the temperature.

It will be easily understood that the above configuration achieves the same functions and effects as those of the embodiments described above.

〔Effect of the invention〕

According to the present invention, the piping has a valve that connects the condenser and the condensate recovery pump suction pipe, and the piping has the valve that connects the condensate recovery pump discharge pipe and the condensate pipe on the inlet side of the condensate purification device. The provision of a flow rate transmitter prevents the performance of condensate circulation storage operation and condenser water draining operation from deteriorating during long-term plant shutdowns.

Higher operational reliability can be achieved by using the conventionally installed condensate recovery pump.

If conventional operating performance were to be maintained without using the present invention, a new dedicated pump or tank would have to be installed in addition to the condensate recovery pump, and the cost would reach several hundred million yen.

In addition, the condensate flow rate is kept constant during condensate circulation storage operation and condenser drain recovery operation.

This makes it possible to prevent overload operation of the condensate recovery pump.

It also has the effect of suppressing the occurrence of rust.

[Brief explanation of drawings]

1 and 7 show a schematic system diagram of an embodiment of the present invention, and FIG. 2 is a system diagram showing the area around the condensate recovery tank shown in FIG. 1 in detail. FIG. 3 shows a schematic system diagram of an example of the prior art, and FIG. 4 is a system diagram showing the area around the condensate recovery tank shown in FIG. 3 in detail. FIGS. 5 and 6 are partial system diagrams and graphs for explaining the problems of the prior art. 1... Nuclear reactor, 2... Turbine, 3... Condenser,
4... Condensate pump, 5... Condensate purification device inlet pipe, 6
...Condensate purification device, 7...Condensate booster pump, 8
Man. 8B... Water supply heater, 9... Water supply pump, 10...
- Water supply pipe, 11... Spillover pipe, 12... Condensate storage tank, 13... Sealing supply pipe % 14... Sealing return pipe. 15... Condensate recovery tank, 16... Condensate recovery pump, 17... Condensate recovery pump discharge pipe, 18... Condensate booster pump bypass pipe, 19... Water supply pump bypass pipe, 20 ...My water supply water recirculation pipe, 21...Condensate water
. Pump suction pipe, 22... Condenser drain pipe, 23...
Condensate passage pipe, 24... Water level control valve, 25... Condensate booster pump bypass valve, 26... Water level control valve. 27...Level switch, 28...Water level transmitter. 29...Water level f, 14WJ device, 30...Spillover valve, 31...Condenser drain valve, 32...Water level transmitter, 33...Water level regulator, 34...Sealed water supply valve, 3
5... Water supply pump bypass valve, 36... Condensate feed water recirculation valve, 37... Condensate recovery pump suction pipe, 38...
Condensate recovery tank outlet valve % 39.49... Flow generator. 40... Condensate recovery pump discharge valve, 41... Condensate connection box, 42... Condensate pump suction main pipe, 43... Signal switch, 44.48... Flow rate regulator agent Patent Attorney Michihito Hiraki 1st
Figure■'' Go○ Figure 2 Figure 3 Figure 4 fFS5r! ! Flow π Q Fig. 7

Claims (5)

[Claims] (1) A condenser that condenses steam from a steam turbine;
A condensate pump that sucks out the condensate in the condenser, a condensate purification device that purifies the condensate sucked out by the condensate pump, a feed pump that supplies water to the steam generator, and a shaft of the feed pump. A condensate recovery tank that recovers sealed water, etc., a condensate recovery pump that sucks out condensate in the condensate recovery tank and sends it to the condenser, and a condensate recovery pump discharge pipe connected to its discharge port. A condenser drain pipe that connects the condenser and a condensate recovery pump suction pipe and has a drain valve in the middle thereof, and a condenser drain pipe that branches from the condensate recovery pump discharge pipe. A condensate device comprising: a condensate communication pipe that reaches an inlet side of the condensate purification device. (2) a condenser that condenses steam from a steam turbine;
A condensate pump that sucks out the condensate in the condenser, a condensate purification device that purifies the condensate sucked out by the condensate pump, a feed pump that supplies water to the steam generator, and a shaft of the feed pump. A condensate recovery tank that recovers sealed water, etc., a condensate recovery pump that sucks out condensate in the condensate recovery tank and sends it to the condenser, and a condensate recovery pump discharge pipe connected to its discharge port. A condenser drain pipe that connects the condenser and a condensate recovery pump suction pipe and has a drain valve in the middle thereof, and a condenser drain pipe that branches from the condensate recovery pump discharge pipe. A condensate communication pipe leading to the inlet side of the condensate purification device, a flow meter that detects the flow rate of condensate flowing through the condensate communication pipe, a condensate flow rate control valve that controls the condensate flow rate, and the flow meter. and means for controlling the opening degree of the flow rate control valve based on the output of the condensing device. (3) The condensate flow rate control valve is provided in the condensate recovery pump discharge pipe, and the condensate communication pipe is branched from the downstream side of the flow rate control valve, as set forth in claim 2. condensing equipment. (4) The condensate flow rate control valve has an opening degree controlled according to the water level of the condensate recovery tank during normal operation, and functions as a water level control valve of the condensate recovery tank. A condensing device according to scope 3. (5) The condensate device according to claim 2, wherein the condensate flow rate control valve is provided in the condensate communication pipe.