JPH0250004A - Control system of pressure inside deaerator - 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 Application Field) The present invention relates to an internal pressure control system for a deaerator installed in a condensing water system of a thermal power plant or a nuclear power plant.

(Conventional technology) FIG. 4 is a schematic diagram of the power generation plant.

First, normal operation of the steam turbine cycle will be explained.

The condensate accumulated in the hot well of the condenser 1 is pressurized by the condensate pump 2, passes through the deaerator water level control valve 3, is heat exchanged by the low pressure heater 4 heated by turbine steam, and then is heated by the deaerator. 5
sent to. This air purifier 5 guides turbine oil from the turbine bleed pipe 19, and directly heats the condensate introduced from the low-pressure heater 4 with the turbine oil to degas it. Also,
The deaerator water level control valve 3 functions to keep the water level of the deaerator 5 constant.

The condensate degassed by the deaerator 5 is further pressurized by the water supply pump 6 and becomes water supply. This feed water undergoes heat exchange with a high-pressure heater 7 heated by turbine extraction air, and is led to a boiler 8 where it is further heated and turned into steam. This steam passes through the main steam stop valve 9 and the main steam control valve 10, and then passes through the high pressure turbine 1.
It will lead you to 1.

In this high-pressure turbine 11, the thermal energy of the steam is converted into kinetic energy, and a generator (not shown) is rotated to generate electricity.

Steam discharged from the high pressure turbine 11 is guided to a reheater 13 where it is reheated, passes through an intermediate steam valve 14, and is introduced into an intermediate pressure turbine 15 to perform work. Steam discharged from the intermediate pressure turbine 15 is guided to the low pressure turbine 16 for further work. The exhaust steam from the low pressure turbine 16 is cooled in the condenser 1 and becomes condensed water.

Next, a case will be described in which a malfunction occurs in the steam turbines 11, 15, 16 and these turbines 11, 15, 16 are tripped.

In this case, the main steam stop valve 9 is fully closed, and instead the high-pressure turbine bypass valve 12 is opened to bypass the high-pressure turbine 11 and direct steam from the boiler 8 to the reheater 13.

Further, the intermediate steam valve 14 is fully opened, the low pressure turbine bypass valve 17 is opened, and the steam from the reheater 13 is guided directly into the condensation zone 1 .

In this way, the steam turbines 11, 15, and 16 are stopped, and the boiler 8 is also stopped to eliminate the problem with the steam turbine.

Next, when removing the malfunction of the steam turbines 11, 15, 16 and starting these steam turbines, the boiler 8 is started first. At this time, the turbine bleed pipe 1
Since turbine bleed air is not being supplied from the deaerator 9 into the deaerator 5, the deaerator pressure control valve 18 is opened to guide steam from another steam generation source into the deaerator 5. Degas the condensate from. and steam turbine 11.15
When the turbine oil from 16° is sufficient, the deaerator pressure control valve 18 is closed. After that, the condensate in the deaerator 5 is
It is degassed by turbine oil air from the turbine oil air pipe 19.

(Problem to be solved by the invention) However, as mentioned above, the steam turbine 11°15.16
These steam turbines 11
, 15, 16, and even the boiler 8, a large amount of heat loss occurs when the boiler 8 is restarted, which causes many problems in terms of the thermal economy of the plant.

This invention was made in consideration of the above circumstances,
It is an object of the present invention to provide a deaerator internal pressure control system that maintains the temperature of water supplied to a boiler at a predetermined value or higher during turbine 1 lip and enables independent operation of the boiler.

[Structure of the invention]

(Means for Solving the Problems) This invention provides a deaerator that heats and deaerates condensate from a condenser using turbine extraction air, and a deaerator that allows steam to be introduced from another steam generation source into the deaerator. a pressure detector that detects the pressure inside the deaerator; and a temperature detector that detects the temperature of feed water supplied to the boiler located downstream of the deaerator. and a deaerator pressure control device that determines the valve opening degree of the deaerator pressure control valve based on the detection signals from the pressure detector and the temperature sensor during a turbine trip, and the deaerator pressure control device The control device includes a temperature controller that sets the valve opening degree of the deaerator pressure control valve based on the detection signal from the temperature detector, and a temperature controller that sets the valve opening degree of the deaerator pressure control valve based on the detection signal from the pressure detector. A pressure controller that sets the valve opening of the pressure control valve, and a high value selector that selects a signal with a large valve opening value from among the valve opening signals from the temperature controller and the pressure controller. It is constructed with

(Function) At the time of turbine trip, the main steam stop valve etc. are closed and the supply of turbine oil to the deaerator is reduced, and the internal pressure of the deaerator decreases, so the pressure of the deaerator pressure control device is reduced. A controller sets the valve opening degree of the deaerator pressure saw control valve based on the detection signal from the pressure detector. At the same time, since the turbine bleed air to the deaerator is reduced, the temperature of the feed water supplied to the boiler is also reduced. Therefore, the temperature controller of the deaerator pressure control I device sets the valve opening degree of the deaerator pressure control valve based on the detection signal from the temperature detector.

The deaerator pressure control valve is controlled by a valve opening signal of a larger value from the pressure controller or the temperature controller. As a result, when the turbine trips, a large amount of steam from other steam generation sources flows into the deaerator through the deaerator pressure control valve, and the internal pressure of the deaerator is controlled to an appropriate value. .

Therefore, the temperature of water supplied to the boiler can be maintained at a predetermined value or higher, and the boiler can be operated independently.

(Example) Embodiments of the present invention will be described below based on the drawings.

Figure 2 shows the internal pressure IIJ Il of the deaerator according to the present invention.
1 is a partial system diagram of a turbine power generation plant to which an embodiment of the L system is applied, and FIG. 1 is a block diagram showing the configuration of the deaerator pressure control device of FIG. 2.

In this embodiment, the same parts as in the conventional example are given the same reference numerals.

As shown in FIG. 2, the deaerator 5 heats and deaerates condensate from the condenser 1 using turbine extraction air.

A steam pipe 20 equipped with a deaerator pressure control valve 18 is connected to the deaerator 5, and when the deaerator pressure control valve 18 is opened, steam from other steam generation sources is transferred to the deaerator. It is provided so that it can be introduced into 5. A turbine bleed pipe 19 is connected to the steam pipe 20, and a bleed check valve 21 is installed in the turbine bleed pipe 19. Turbine bleed air from the steam turbines 11 , 15 , 16 is provided to be supplied into the deaerator 5 via the targon bleed pipe 19 .

Now, the deaerator pressure control valve 18 has a deaerator pressure control device 2.
2 is connected. A pressure detector 23 and a temperature detector 24 are connected to this deaerator pressure control device 22 . This pressure detector 23 is attached to the deaerator 5 and detects the pressure inside the deaerator 5.

Further, the temperature detector 24 is installed upstream of the boiler 8 and detects the temperature of the water supplied to the boiler 8.

As shown in FIG. 1, the deaerator pressure control device 22 controls the temperature]! 25 and a pressure controller 26, and further includes a temperature switch 27, a pressure setting switch 28, and a high value selector 29.
It is composed of:

A temperature detection signal A and a temperature set value signal B from the temperature detector 24 are input to the temperature controller 25 . Temperature control'a
The controller 25 calculates the valve opening degree of the deaerator pressure control valve 18 from the deviation of these signals A and B, and outputs a temperature side valve opening degree signal C to the temperature switch 27. The temperature switch 27 switches the temperature side valve opening signal C from the temperature controller 25 to the high value selector 2 only when the boiler 8 is operated independently during a turbine trip.
Output to 9.

The pressure setting switch 28 uses a pressure setting value 30 in the deaerator 5 during normal operation of the turbine as a pressure setting signal during normal operation. pressure setting (a31 is inputted as the pressure setting signal E during boiler independent operation.The pressure setting switch 28 switches the pressure setting signal during normal operation during normal operation of the turbine, when the turbine trips and the boiler 8 is operated independently). When doing so, the boiler independent operation pressure setting signal E is switched and output to the pressure control t[l326.

Here, as shown in FIG. 3, the pressure setting value 30 during normal turbine operation is set to about 0.35 atg, and the pressure setting value 31 during boiler independent operation is set to about satg. The solid line in FIG. 3 is a graph showing the relationship between the pressure inside the deaerator 5, which changes due to turbine extraction, and the turbine load during normal turbine operation.

The pressure shown in Figure 1! ! The 111tll device 26 compares the pressure detection signal F from the pressure detector 23 with the pressure setting signal during normal operation or the pressure setting signal E during boiler independent operation to find a deviation, and performs deaeration based on this deviation. Set the valve opening degree of the pressure control valve 18, and set the pressure side valve 1711 degree signal 6.
It is output to the high value selector 29 as a value.

The high value selector 29 determines and controls the valve opening of the deaerator pressure control valve 18 based only on the pressure side valve opening signal G from the pressure controller 26 during normal turbine operation. In addition, when the boiler is operating independently, the high value selector 29 selects one of the pressure side valve opening signal G and the temperature side valve opening signal C which has a larger valve opening value, and uses this selection signal H as Based on the deaerator pressure l! The valve opening degree of the one-section valve 18 is controlled.

Next, the action will be explained.

During normal operation of the turbine, the pressure setting switch 28 outputs a pressure setting value signal during normal operation to the pressure controller 26 . Further, since the temperature switch 27 does not output a signal to the high W1 selector 29, the high value selector 29
The valve opening degree of the deaerator pressure crab im valve 18 is controlled by using the pressure side valve opening signal G from the L regulator 26 as the selection signal 1]. Eventually, when the amount of turbine bleed air from the turbine bleed air pipe 19 increases, the pressure regulator 26 outputs a signal to close the deaerator pressure control valve 18. Therefore, from now on, the inside of the deaerator 5 will be controlled only by the turbine oil air from the turbine bleed air 19.

Next, a case will be described in which a malfunction occurs in the steam turbine and it is desired to trip only the steam turbine and operate the boiler 8 independently.

In this case, the boiler independent operation signal I is output to the pressure setting switch 28 and temperature switch 27 of the deaerator pressure control device 22. In response to this boiler independent operation signal I, the pressure setting switch 28 outputs the boiler independent operation pressure setting signal E to the pressure controller 26, and the temperature switch 27 outputs the signal from the temperature controller 25 to the high value selector 29. It will be output. The pressure controller 26 compares the pressure detection signal F from the pressure detector 23 with the boiler independent operation pressure setting signal E,
The valve opening degree of the deaerator pressure control valve 18 is set based on the deviation, and a pressure side valve opening degree signal G is output to the high value selector 29.

Furthermore, the temperature controller 25 compares the temperature set value signal B and the temperature detection signal A from the temperature detector 24, and outputs a temperature side valve opening signal C to the temperature switch 27 based on the difference. This temperature switch 27 outputs this temperature side valve opening degree signal C to the high value selection 829.

The high value selector 29 selects either one of the pressure-side valve opening signal G and the temperature-side valve opening signal C, which has a larger valve opening value, as the selection signal H. Controls the opening degree of the pressure regulating valve 18.

As a result, even when turbine bleed air is not being supplied from the turbine bleed pipe 19 to the deaerator 5 at the top of the turbine, a large amount of steam is supplied from another steam generation source to the deaerator 5 through the steam pipe 20. Therefore, the inside of the deaerator 5 is controlled to an appropriate pressure that is approximately the same as the pressure setting value 31 during boiler independent operation. The temperature of the water supply to boiler 8 is approximately 180.
The temperature can be controlled above a predetermined value, and the boiler can be operated independently.

In addition, in the boiler independent operation as described above, the pressure in the deaerator 5 is generally controlled to be constant by the pressure side valve opening signal G, but the temperature of the inlet water supply to the boiler 8 drops transiently. In this case, the value of the temperature side valve opening signal C is larger than the pressure side valve opening signal G, so the valve opening of the deaerator pressure control valve 18 is controlled based on this temperature side valve opening signal C. will be done.

(Effect of the invention) As described above, the internal pressure υ11 of the deaerator according to the present invention
According to the Il system, the deaerator pressure control device includes a temperature controller that sets the valve opening degree of the deaerator pressure control valve based on a detection signal from the temperature sensor, and a temperature controller that sets the valve opening degree of the deaerator pressure control valve based on a detection signal from the temperature sensor; A pressure controller that sets the valve opening of the deaerator pressure control valve based on the temperature signal, and a valve opening that has a large value among the valve opening signals from the temperature controller and the pressure controller. Since it has a high value selector that selects a high value, when the turbine trips, a large amount of steam flows into the deaerator from other steam generation sources through the deaerator pressure control valve, and the internal pressure of the deaerator is maintained at an appropriate level. controlled to a certain value. Therefore, the temperature of the water supplied to the boiler can be maintained at a predetermined level or higher, and the boiler can be operated independently.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the deaerator pressure control system shown in Fig. 2, and Fig. 2 shows a part of a turbine plant to which an embodiment of the deaerator internal pressure control system according to the present invention is applied. FIG. 3 is a diagram showing a pressure setting value during normal operation and a pressure setting value during boiler independent operation, respectively, and FIG. 4 is a schematic system diagram showing a power generation plant to which the present invention is applied. 22... Deaerator pressure control device, 23... Pressure detector, 25... Temperature controller, 26... Pressure regulator, 29
...High value selector, C...Temperature side valve opening signal, G...
・Pressure side valve opening signal. Applicant's agent Hisashi Hatano

Claims (1)

[Claims] A deaerator that heats condensate from the condenser using turbine extraction air to degas it; a deaerator pressure control valve that allows steam to be introduced into the deaerator from another steam generation source; a pressure sensor that detects the pressure of a deaerator pressure control device that determines the opening degree of the deaerator pressure control valve based on the detection signal, and the deaerator pressure control device includes a deaerator pressure control device that determines the opening degree of the deaerator pressure control valve based on the detection signal, a temperature controller that sets the valve opening degree of the deaerator pressure control valve based on the detection signal from the pressure detector; a pressure controller that sets the valve opening degree of the deaerator pressure control valve based on the detection signal from the pressure detector; A deaerator comprising: a high value selector that selects a signal with a large valve opening value from among the valve opening signals from the temperature controller and the pressure controller; Internal pressure control system.