JPS63243609A - Feedwater heater drain controller - 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] [Object of the Invention] (Industrial Field of Application) The present invention relates to a feed water control device for a steam turbine plant such as a nuclear power plant, and particularly for a nuclear power plant equipped with a feed water heater drain pump up system. This invention relates to a feed water heater drain control device in a J5 plant.

(Prior art) Generally, in a nuclear power plant, a feedwater heater is installed in the reactor condensate/feedwater system from the condenser to the reactor, and this feedwater heater uses turbine extraction to remove air from the condenser. Condensate or feed water is heated. The heated condensate or feed water is fed to the reactor as a steam generator. on the other hand,
Turbine bleed air that heats condensate or feed water in each feed water heater is condensed and sent as drain in a cascade to the feed water heaters on the low pressure side, and finally recovered to the condenser.

Recently, as a means to further improve the plant efficiency of nuclear power plants, a system has been developed in which the drain from the feed water heater is not guided in a cascade and collected in the condenser, but is instead fed to the condensate pipe via a drain pump. That is, feedwater heater drain pump-up systems are being used.

In this feedwater heater condensate pump-up system, the saturated condensate condensed in the feedwater heater is directly mixed with condensate from the condenser, which greatly contributes to the upper limit of the condensate temperature and thus the feedwater temperature. The efficiency of about 0.5%
It can be improved to a certain extent. For this reason, the adoption of feedwater heater drain pump-up system technology is being considered in J3, a state-of-the-art nuclear power plant.

By the way, the feedwater heater drain pump-up system can be broadly divided into the low-pressure feedwater heater drain pump-up system, which pumps up the drain generated in the low-pressure feedwater heater and supplies it to the I condensate pipe, and the system which pumps up the drain from the high-pressure feedwater heater. There are two types of drain pump-up systems: a high-pressure feed water heater drain pump-up system that pumps up the water and supplies it to the condensate pipe, and each drain pump-up system can be used singly or in combination.

FIG. 6 is a system diagram illustrating a reactor condensate/water supply system of a nuclear power plant equipped with high-pressure and low-pressure feedwater heater drain pump-up systems.

A nuclear power plant includes a steam turbine 2 driven by steam generated in a nuclear reactor 1 serving as a steam generator.

Work is done in the steam turbine 2, and the expanded steam is guided to the condenser 3, where it is condensed and becomes condensed water. This condensate is temporarily stored in a condenser 3, pressurized by a condensate pump 4, and filtered and treated with salt by a condensate purifier 5. The filtered and desalted condensate is then heated in the low-pressure feed water heater 6 and sent to the water pump 7, where the pressure is further increased. The condensate pressurized by the feedwater pump 7 becomes feedwater and is guided to the high-pressure feedwater heater 8 , where it is further heated and then returned to the reactor 1 through the water supply pipe 9 .

On the other hand, turbine oil is supplied to the low-pressure and high-pressure feedwater heaters 6.8 through a turbine bleed pipe (not shown) extending from the steam turbine 2 to heat each feedwater. ! In step 16.8, heat exchange is performed to heat the double water, and this condensate is heated and condensed to become drain. This drain is sequentially sent to the feed water heater on the low pressure side through the drain pipe 11 and then collected in the drain tank 12. The drain collected in the drain tank 12 is temporarily stored, and then transferred to the drain pump 1.3.
is guided and boosted. The pressurized drain is sent to the condensate pipe 10 and mixed with condensate.

Further, the water level of the drain tank 12 is detected by a water level gauge 15. The detected water level signal is compared with a water level set value by a drain tank water level controller 16.17, and a signal for correcting the deviation is given to a water level regulating valve 18.19.

By adjusting the water level control valves 18 and 19 at 171 degrees, the water level in the drain tank 12 is maintained constant.

As described above, according to the feedwater heater drain pump-up system, the drains of the feedwater heaters 6 and 8 can be directly mixed with condensate, and the condensate temperature and eventually the feedwater temperature can be increased, so that it can be used in nuclear power plants. Efficiency can be improved.

(Problem to be solved by the invention) In a nuclear power plant that employs a feedwater heater drain pump-up system, the reactor 1 as a steam generator
As shown in Figures 6 and 7, the water supply to the reactor is controlled by changing the rotation speed of the water pump 7 depending on the water level of the reactor 1, the water supply flow rate, and the main steam flow rate to maintain the reactor water level at a constant level. are doing.

On the other hand, the water level in the drain tank 912.12 of the feed water heater drain pump-up system is kept constant by adjusting the opening of the water level control valve 18.19.
For water level control, when the opening degree of the water level control valve 18 changes, the flow rate of drain supplied to the condensate pipe 10 changes, so the flow rate of water supplied to the reactor 1 fluctuates with an R delay.

As a result of this, an adverse effect occurs in that the reactor water level fluctuates. In particular, when the flow rate of condensate supplied to the condensate pipe 10 increases rapidly, such as when the drain pump 13 is started, there is a time delay before it appears as a change in the flow rate of water supplied to the reactor 1, so water supply control cannot be performed quickly. If this could not be done, the reactor water level in the reactor 1 would become abnormally high, and in severe cases, there was a risk that the sound operation of the nuclear power plant would be disrupted, such as by causing a scram in the reactor.

The present invention was made in consideration of the above-mentioned circumstances, and it stabilizes the flow rate of drain fed from the drain tank to the condensate/water supply system, and prevents fluctuations in the drain flow rate due to fluctuations in the tank water level in the drain tank. Moreover, it reliably prevents water supply II (I
It is an object of the present invention to provide a feed water heater drain control device that can quickly and stably perform t to ensure healthy operation of a plant.

[Structure of the invention]

(Means for solving the problem) The feed water heater drain t, 1lIIl device according to the present invention has the following features:
A feed water heater that heats condensate or feed water is installed in the condensate/water supply system, and after condensed by this feed water heater is stored in a drain tank, it is supplied to the condensate/water supply system via a drain pump. In the feedwater heater drain 1Ill tall apparatus comprising a feedwater heater drain pump-up system, the feedwater heater drain pump-up system comprises:
It is equipped with a drain flow fa, i1m device that feeds the required drain flow rate of ① from the drain tank to the condensate φ water supply system, and a drain tank water level control device that controls the tank water level in the drain tank.

(Function) This feed water heater drain control device is equipped with a feed water heater drain pump up system, and this feed water heater drain pump up system supplies a predetermined drain flow rate of m from the drain tank to the condensate/water supply system. Since the drain flow rate adjustment device is equipped with a drain flow rate adjustment device, it is possible to supply the required and stable drain flow rate to the condensate/water supply system, and this drain flow rate does not change due to changes in the water level in the drain tank. Since the drain flow b1 can be reliably prevented from becoming a disturbance in the water supply flow of the condensate/water supply system, the water supply can be controlled stably and quickly.

Moreover, since the feed water heater drain pump-up system is equipped with a drain tank water level control device, the tank water level in the drain tank can be maintained at a required level.

(Embodiment) Hereinafter, an embodiment of the feed water heater drain control device according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an example in which the feed water heater drain control device of the present invention is applied to a reactor condensate/feed water system of a nuclear power plant.

The reactor condensate/water supply system 20 of this nuclear power plant is
Since it is not different from the reactor condensate/water supply system shown in FIGS. 6 and 7, the same reference numerals will be given and the explanation will be omitted.

The above-mentioned reactor condensate/water supply system 20 receives condensate condensed and generated by high-pressure and low-pressure feed water heating Z8.6.
A feedwater heater drain pump-up system 21 is provided which injects into the water supply system 20. This feed water heater drain pump up system 21 is a high pressure feed water heating P! High-pressure feed water heater drain bomb system 22 that injects the drain generated at t8 into the condensate pipe 10 of the reactor condensate/water supply system 20
and a low-pressure feedwater heater drain pump-up system 23 that injects the drain generated in the low-pressure feedwater heater 6 into the condensate pipe 10.
and has. In addition, by heating the feed water or condensate with the high-pressure and low-pressure feed water heaters 8.6, the turbine oil air is condensed and becomes drain, and this drain is passed through the drain pipe 24.
The water is sequentially sent to the feed water heater on the low pressure side through the drain tank 25, and then collected in the drain tank 25.

The high-pressure and low-pressure feedwater heater drain pump-up systems 22.23 pump up a required n drain flow rate from the drain tank 25 (for example, about 30% and about 15% of the total feedwater flow rate of the reactor condensate/feedwater system 20). ) to reactor condensate/
A drain flow rate adjusting device 27 that supplies water to the water supply system 20 and a drain tank water level control device 28 (see FIG. 2) that controls the tank water level in the drain tank 25 are arranged in a basket λ.

The high-pressure and low-pressure feedwater heater drain pump-up systems 22 and 23 are shown in FIG. Let me explain using an example.

The drain 2Rffi adjustment device 1ff27 of the high-pressure feedwater heater drain pump-up system 22 includes a drain recovery line 30 connected from the drain tank 25 to the condensate pipe 10 of the reactor condensate/feedwater system 20.
A drain pump 31, a drain flow rate control valve 32, and a drain 1133 such as an orifice are sequentially provided. This drain recovery line 30 may be provided with a drain purification device (not shown) in order to improve the water quality of the drain recovered to the reactor condensate/water supply system 20. However, drain tank 2
The drain once stored in 5 is pumped up by the drain pump 31, and then transferred to the drain 2Q by the drain flow controller 32.
The water is injected into the condensate pipe 10 with the amount adjusted to a required amount (for example, about 30% of the total water supply flow rate). .

In addition, the drain tank water level control 11fi 28 is equipped with a drain line 35 that leads the drain in the drain tank 25 to the feed water heating yA6 of the next stage, and a drain line 36 that leads the drain to the condenser 3. line 35.3
Drain tank water level control valves 37 and 38 are provided at 6. The opening degree of this drain tank water level control valve 37, 38 is controlled 60 by an output signal from a drain tank water level controller 40, 41.

On the other hand, the tank water level in the drain tank 25 is in the water level section 143.
The actual tank water level signal detected by the water level gauge 43 is sent to the drain tank water level controller 40, 41 and the flow rate setting device 44, respectively. Among these, the input actual tank water level signal is compared with the water level setting signal (water level setting value) in the drain tank water level controller 40 and 41, and a signal for correcting the width difference is sent to the drain tank water level control valve 37.
38, during which the melon is adjusted. This valve opening degree w
The amount of drain flowing out is controlled by the four sections, and the drain tank 25
The water level in the tank is controlled to a predetermined level.

In addition, the flow rate setting e144 inputs the actual tank water level signal from the water level gauge 43 to correct the drain gutter setting value, and the drain water amount setting signal (drain flow rate setting value) from the flow rate setting height 44 is the flow rate. It is output to the controller 45.

The actual drain flow rate signal detected by the drain flow meter 33 is input to the flow rate controller 45, and this actual drain flow rate signal is compared with the drain flow rate setting signal by the flow rate controller 45. , the deviation signal is sent to the drain flow rate control valve 32.
is output to. The valve opening degree of the drain flow rate control valve 32 is adjusted manually based on the deviation signal, so that the drain flow rate injected (recovered) into the condensate pipe 10 of the reactor condensate/water supply system 20 takes a required stable value. is set to

In this high-pressure feed water heater drain pump-up system 22, the drain flow rate (drain recovery amount) injected from the drain tank 25 into the condensate pipe 10 of the reactor condensate/feed water system 20 is adjusted and controlled by the drain flow rate control valve 32, While attempting to stabilize the drain flow rate, the feed water heater 6 and condensate water 33 in the next stage and subsequent stages are required to collect drain to control the water level in the drain tank 25.

In this high-pressure feed water heater drain pump-up system 22, the drain suspension in the drain tank 25 is
As shown in the figure, the flow rate of drain that is processed and injected (recovered) from the drain tank 25 into the condensate pipe 10 of the reactor condensate/water supply system 20 is regulated to a constant level by adjusting the opening of the drain flow control valve 32. Since it is possible to prevent a change in the drain flow rate due to a change in the tank water level in the drain tank 25 and to stably supply a predetermined amount of drain flow rate, it is possible to eliminate disturbances to changes in the condensate flow rate and thus to changes in the supply water flow rate.

In this case, the water level in the drain tank 25 is controlled so that a part of the stored drain is transferred to the feed water heater 6 or condenser 3 of the next stage and subsequent stages using the opening degree A11 of the drain tank water level control valve 37.38.
This is done by guiding the person.

Therefore, by employing this high-pressure feedwater heater drain pump-up system 22, it is possible to provide a feedwater heater drain 1t11 control device in which fluctuations in the water level in the drain tank 25 do not directly disturb the water supply flow rate to the reactor 1.

However, if the drain water level in the drain tank 25 suddenly and significantly decreases, this change in the drain water level can be detected using the water level gauge.
3 and sends it to the flow rate setting device 44.
4 to lower the drain flow rate setting and raise the tank water level.

Next, another embodiment of the feed water heater drain control device according to the present invention will be described with reference to FIGS. 4 and 5.

The feedwater heater drain 1lltllll device shown in FIG. The configuration is basically different from the configuration shown in FIG. 2 in that the flow rate setting device 44 of the mouth adjustment device 27 is inputted, and the other configurations are the same, so the same reference numerals are given and the explanation will be omitted.

The feed water heater drain control system shown in Figure 4! 27 does not necessarily set the drain 2M lift setting value by the flow rate setting device 44 to a constant value, but, for example, changes in the feed water flow M of the reactor condensate/water supply system 20 are detected by the feed water flow meter 48, and the actual water supply is determined. A flow rate signal is sent to the flow rate setting device 44, and this flow rate setting device 44 outputs a drain flow rate setting value corresponding to the water supply flow rate change setting value as a drain flow rate setting signal from the outflow setting device 44, as shown in FIG. It is.

In this case, the drain flow rate fed from the drain tank 25 to the reactor condensate/water supply system is expressed as shown in FIG. 5, and the drain flow rate is proportional to the increase in the feed water flow rate of the reactor condensate/water supply system 20. It is increasing as the number of people increases. When the amount of generated condensate exceeds the drain flow rate, part of the generated condensate is suspended by the water supply from the next stage onward! condenser or condenser 3.

In addition, in the feed water heater drain control device 2Il shown in FIG. 4, an example is shown in which a change in the flow rate of the feed water flow claw detected by the feed water flow meter 48 is used to change the drain flow rate set value of the flow rate setting device 44. However, the load signal of the turbine/generator may be used instead of the change in the flow direction of the water supply.

In addition, in the embodiment, an example was explained in which a drain flow meter was provided on the downstream side of the drain flow rate control valve in the drain recovery line, but this drain flow meter can be used in any drain recovery line that extends from the drain tank outlet side to the condensate pipe inlet. , may be provided at any position. Further, although an example has been shown in which the drain recovery line is connected to the condensate pipe of the reactor condensate/water supply system, it may be connected to the water supply pipe on the discharge side of the water supply pump.

Furthermore, in each of the embodiments, an example is described in which a high-pressure feedwater heater drain pump-up system is provided. However, if the drain tank of the low-pressure feedwater heater drain pump-up system is on the lowest pressure side of the low-pressure feedwater heater, there is no drain line leading to the next stage feedwater heater. In some cases, only condenser recovery is required.

In addition, this feed water heater drain control device can be used not only in nuclear power plants, but also in steam generators such as steam turbines and boilers.
It can also be applied to steam turbine plants using S.

〔Effect of the invention〕

As described above, the feed water heater drain control device according to the present invention includes a feed water heater drain pump up system, and this feed water heater drain pump up system supplies condensate and water at a required drain flow rate of G from the drain tank. Since it is equipped with a condensate flow rate adjustment device that supplies water to the system, and a drain tank water level control device that performs the tank water level a, II II in the drain tank, it is possible to control the condensate flow rate that is supplied from the drain tank to the condensate/water supply system. It is possible to stabilize the water supply flow rate, prevent fluctuations in the drain flow rate due to fluctuations in the tank water level in the drain tank, and eliminate disturbances to the water flow crystals, making it possible to control the water supply flow rate stably and quickly. This can ensure the healthy operation of the plant and improve reliability.

Further, the tank water level in the drain tank is stably maintained at a predetermined level by the drain tank water level control device.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the feedwater heater drain control device according to the present invention, and is a system diagram showing a reactor condensate/water supply system of a nuclear power plant equipped with this feedwater heater drain υ control device. FIG. 2 is a block diagram showing one embodiment of the feed water heater drain control device, FIG. 3 is a diagram showing an example of the drain f, 11 il1 by the feed water heater drain control device, and FIG. 4 is a diagram showing an example of the drain f, 11 il1 according to the present invention. A configuration diagram showing another embodiment of the feedwater heater drain ilJ Oll device, FIG. 5 is a diagram showing an example of drain control by the feedwater heater drain control V device shown in FIG. 4, and FIG. 6 is a diagram showing a conventional nuclear power system. FIG. 7 is a system diagram showing a nuclear reactor condensate/water supply system of a power generation plant, and is a diagram showing a feed water heater drain control device provided in a conventional nuclear power generation plant. 1... Nuclear reactor (steam generator), 2... Steam turbine, 3... Condenser, 4... Condensate pump, 6... Low pressure feed water heater, 7... Water feed pump , 8... High-pressure feed water heater, 9... Water supply pipe, 10... Condensate pipe, 20...
Reactor condensate/water supply system, 21... Feedwater heater drain pump up system, 22... High pressure feedwater heater drain pump up system, 23... Low pressure feedwater heater drain pump up system, 25...・Drain tank, 27
...Drain flow rate adjustment device, 28...Drain tank water level control device, 30...Drain recovery line, 31...
Drain pump, 32...Drain flow rate control valve, 33...
・Drain flow δ) meter, 35.36...Drain line, 3
7.38...Drain tank water level control valve, 40.41.
...Drain tank water level controller, 43...Water level gauge, 44
...Flow rA setting device, 45...Flow rate controller, 48...
・Water supply flow meter. Figure 2 Load (steam targon, Bonfire 1) Figure 3

Claims (1)

[Claims] 1. A feed water heater for heating condensate or feed water is provided in the condensate/water supply system, and after storing condensate condensed by the feed water heater in a drain tank, In a feed water heater drain control device equipped with a feed water heater drain pump-up system that supplies condensate and water to a water supply system, the feed water heater drain pump-up system supplies a required flow rate of condensate from a drain tank to the condensate and water supply systems. A drain control device for a feed water heater, comprising: a drain flow rate regulating device for supplying drain water to the system; and a drain tank water level control device for controlling a tank water level in the drain tank. 2. The feed water heater drain control device according to claim 1, wherein the drain tank water level control device is configured to control the drain tank water level by a drain line that guides the drain in the drain tank to the condenser. 3. The drain tank water level control device is a patent that is set to control the drain tank water level using a drain line that leads the drain in the drain tank to the feed water heater in the next stage and a drain line that leads the drain to the condenser. Claim 1
Feed water heater drain control device as described in paragraph. 4. The drain flow rate adjustment device is equipped with a drain pump, a drain flow rate control valve that adjusts the drain flow rate, and a drain flow meter that measures the actual drain flow rate in the drain recovery line connected from the drain tank to the condensate/water supply system. Claim 1
Feed water heater drain control device as described in paragraph. 5. The opening degree of the drain flow rate control valve is adjusted by the output signal from the flow rate controller, while the flow rate controller compares the drain flow rate setting signal from the flow rate setting device with the actual drain flow rate signal from the drain flow meter. 5. The feed water heater drain control device according to claim 4, wherein the feed water heater drain control device is configured to output the deviation signal. 6. The flow rate setting device receives an actual tank water level signal from a water level meter that detects the drain tank water level, and the drain flow rate setting value is corrected based on this water level signal.
Feed water heater drain control device as described in paragraph. 7. The flow rate setting device receives an actual water supply flow rate signal from a water supply flow meter provided in the condensate/water supply system, and corrects the drain flow rate setting value based on this actual water supply flow rate signal. The feedwater heater drain control device described in . 8. The feed water heater drain control device according to claim 5, wherein the flow rate setting device receives a load signal of the steam turbine/generator and corrects the drain flow rate setting value based on this load signal.