JP3286478B2 - Operating method of steam turbine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating a steam turbine employed in, for example, a thermal power plant or a nuclear power plant, and in particular, reheats high-pressure turbine exhaust steam by using a part of inlet steam of a high-pressure turbine. The present invention relates to a method for operating a steam turbine provided with a moisture separation heater.

[0002]

2. Description of the Related Art Conventionally, a steam turbine provided with a high-pressure turbine and a low-pressure turbine usually includes a moisture separation heater for reheating steam discharged from the high-pressure turbine. In order to reheat the steam, a second stage heater using a part of the high pressure turbine inlet steam as a heating source and a first stage heater using a part of the extracted steam extracted from the high pressure turbine as a heating source are provided. I have.

The low-pressure turbine is driven by the reheated steam. In this case, the moisture separation heater is provided with a heating steam stop valve for shutting off the heating steam at the high-pressure turbine inlet steam. When the steam temperature at the outlet of the moisture separation heater becomes equal to or higher than a specified value, the heating steam stop valve is fully closed by a signal from the temperature detector. Incidentally, as related to this, for example, JP-A-59-77012 is cited.

[0004]

As described above, in the conventional turbine, the steam temperature at the outlet of the moisture separation heater is higher than a specified value.
Alternatively, when the exhaust pressure of the high-pressure turbine becomes equal to or less than a specified value, an operation method is adopted in which the heating steam stop valve is fully closed by a detection signal from each detector. Since the heater is closed, the heating of the exhaust steam of the high-pressure turbine by the moisture separation heater is instantaneously stopped, and the steam temperature change rate of the low-pressure turbine is large, which may cause vibration of the low-pressure turbine. Yes, and in some cases, a steam turbine trip due to turbine vibration may occur.

[0005] The present invention has been made in view of the above, and an object of the present invention is to provide a steam turbine equipped with this kind of moisture separation heater, in which the generation of vibration of the low-pressure turbine is sufficiently suppressed. An object of the present invention is to provide a method for operating a seed steam turbine.

[0006]

In other words, the present invention provides a method for controlling the operation of a steam turbine when the steam temperature at the outlet of the moisture separation heater becomes equal to or higher than a specified value or when the exhaust pressure of the high-pressure turbine becomes equal to or lower than a specified value. The heating of the exhaust steam of the high-pressure turbine by the separation heater is gradually reduced, so that the steam temperature change rate of the low-pressure turbine is not reduced to achieve the intended purpose.

[0007] As means for reducing the rate of change of the steam temperature of the low-pressure turbine, the setting of the heating steam pressure of the heating steam control valve of the moisture separation heater is gradually reduced by the saturation pressure of the steam temperature of the low-pressure turbine. Gradually narrow the opening of the heating steam stop valve of the moisture separator heater. The heating steam pressure setting of the heating steam control valve of the moisture separator / heater is gradually reduced according to the steam temperature change rate of the low pressure turbine.

[0008] Further, the heating steam pressure setting of the heating steam control valve of the moisture separation heater is gradually reduced, and when the turbine vibrates, the change of the heating steam pressure setting of the heating steam control valve is stopped. The heating steam pressure setting of the heating steam control valve of the moisture separation heater is gradually reduced, and when turbine vibration occurs, the heating steam pressure setting change rate of the heating steam control valve is changed. It may be possible to gradually narrow the opening of the heating steam control valve of the moisture separation heater.

[0009]

According to the operation method of the steam turbine,
When the operation is stopped, if the outlet steam temperature of the moisture separation heater becomes higher than the specified value or the exhaust pressure of the high pressure turbine becomes lower than the specified value, the heating of the exhaust steam of the high pressure turbine by the moisture separation heater gradually decreases. Therefore, the heating of the steam discharged from the high-pressure turbine by the moisture separation heater does not change instantaneously. Therefore, the rate of change in the steam temperature of the low-pressure turbine is small, that is, the rate of temperature change is small and the vibration of the low-pressure turbine is generated. Is sufficiently suppressed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 shows a system of a steam turbine plant including the high-pressure turbine 4, the low-pressure turbine 6, the steam generator 1, and the moisture separation heater 5.

The steam generated by the steam generator 1 enters the high-pressure turbine 4 through a steam stop valve 2 and a steam control valve 3 installed in a steam pipe 51, and the discharged steam is
The moisture is separated by the moisture separation heater 5 and heated in the moisture separation heater 5 by the steam guided from the steam generator 1 through the steam pipe 52 and the steam guided from the high pressure turbine 4 through the steam pipe 54. Then, the gas flows into the low-pressure turbine 6 through the steam pipe 53 to drive the low-pressure turbine 6 and the generator 32 connected thereto.

The steam discharged from the low-pressure turbine is supplied to a condenser 7
Is condensed and condensed. The condensed water condensed in the condenser 7 is boosted in pressure by a feed / recovery pump 8 installed in a feed / recovery pipe 61, and is supplied to a feed water heater 9 by turbine extracted steam guided from the high-pressure turbine 4 through an extraction pipe 71. The temperature is increased and sent to the steam generator 1.

On the other hand, the steam branched from the upstream side of the steam stop valve 2 passes through the heated steam stop valve 10 provided in the steam pipe 52, and passes through the heated steam control valve 11 or the heated steam control valve bypass valve 12. Via heating steam,
The extracted steam branched from the high-pressure turbine 4 is supplied to a steam pipe 54.
Through the heating steam stop valve 46 provided as
The high-pressure turbine exhaust steam is heated by the moisture separation heater 5 to become a drain, and flows into the heater drain tanks 38 and 40 through drain pipes 81 and 86.

As for the drain flowing into the heater drain tanks 38 and 40, the detection values of the drain tank level meters 35 and 41 are inputted to the control device 16 so that the drain tank level becomes constant. The drains are guided to the feed water heater 9 by adjusting the openings of the heater-side level adjustment valves 34 and 42 by using the heaters, or the condenser-side level adjustment valves 33 and 43 installed in the drain pipes 85 and 88 are adjusted. It is adjusted so that the drain is sent to the condenser 7 by the drain.

The moisture separation heater 5 has a heater and a moisture separator therein, and the heater includes a heating steam stop valve 10 for guiding heating steam from the steam generator 1, a heating steam control valve, and a heating steam control valve. This is a two-stage configuration in which a steam pipe 52 provided with a valve 11 and a heating steam control valve bypass valve 12 and a steam pipe 54 branched from the high-pressure turbine 4 and provided with a heated steam stop valve 46 are provided.

The two-stage heater has a first-stage heater using the extracted steam of the high-pressure turbine 4 as the heating steam and a second-stage heater using the steam generator 1 as the heating steam due to the difference in the enthalpy of the heating steam. Due to the difference in the enthalpy of the heating steam, if the second stage heater alone is operated in the state where the first stage heater is stopped, damage such as heat distortion or thermal deformation may occur in the moisture separation heater 5. It is necessary to operate the second-stage heater in the first-stage heater operating state.

The heater is provided for extracting a non-condensable gas in the heater, flowing partially scavenging steam to prevent supercooling by drain in the heat transfer tube, and to secure a stable steam amount. Vent pipes 83 and 84 and vent pipe 8
9, 90 are installed, and it is necessary to prevent blockage of this vent system. Therefore, this heater is connected to the vent pipe 8
3, 84 and vent pipes 89, 90,
The vent pipes 83 and 84 have condenser side vent valves 14 and 44 leading to the condenser 7, and the vent pipes 89 and 90 have feed water heater side vent valves 15 and 4 leading to the feed water heater 9.
5 are provided respectively.

The steam turbine plant system thus configured is further provided with a control device 16 for controlling the operation of the moisture separation heater 5. The control device 16 includes a heating steam stop valve 1 installed in a steam pipe 52.
0, heating steam control valve 11, heating steam control valve bypass valve 1
2, and a heated steam stop valve 4 installed in the steam pipe 54
6 includes the control function and the vent piping 8
Condenser side vent valves 14 and 44 on 3, 84, condenser side vent valves 15 and 45 on vent pipes 89 and 90, level adjustment valves 33 and 34 on drain pipes 81 and 85, drain pipe 86 , 88 on each level control valve 42.43.

The control device 16 includes a heating steam pressure gauge 18 flowing through a steam pipe 52, a low-pressure turbine inlet thermometer 19 flowing through a steam pipe 53, and a generator output 3 of a generator 32.
1. Drain tank level gauges 35 and 48 of the heater drain tanks 38 and 40 and drain tank pressure gauges 37 and 50;
The detection signal detected by the feed water heater pressure gauge 36 of the feed water heater 9 and the detection signal detected by the turbine vibrometer 39 for measuring the vibration of the low-pressure turbine 6 and the plant state signal 17 are input to determine the various control operations. Used for writing.

When operating the moisture separation heater, an operation of opening the heating steam stop valve, the heating steam control valve, and the bypass valve of the heating steam control valve to ventilate the heating steam and heat the high-pressure turbine exhaust steam is performed. The plant will be operated. In order to prevent damage to the moisture separation heater from spreading and prevent the turbine from vibrating, the heating steam of the moisture separation heater is passed through the first stage heater in order to perform the reheat operation of the moisture separation heater. Thereafter, the second stage heater ventilation can be achieved by stopping the heating of the high-pressure turbine exhaust steam.

Next, a first embodiment of the control method of the present invention for setting the moisture separation heater to the reheating operation will be described with reference to FIG. The heating steam of the moisture separation heater is passed through the first stage heater and then the second stage.
A method of operating the moisture separation heater by ventilating the stage heater will be described.

First, the case where the ventilation of the first stage heater is started will be described. When ventilating the first-stage heater, the heating steam stop valve 46 installed in the steam pipe 54 is opened. As one means for opening, the heating steam stop valve 46 is opened from the fully closed state to the specified opening degree, held at the opening degree for a certain time, again opened to a larger specified opening degree and held at the opening degree for a certain time. Is fully opened after repeating several times.

As a second means, the valve can be fully opened from the fully closed state to the fully opened state by the operation time inherent to the valve.
Feed water heater side vent valve 45 installed in vent pipe 90
When the backflow of the heating steam from the feed water heater is prevented, the heating steam stop valve 46 is fully opened from before the opening thereof, and after the condenser side vent valve 44 installed in the vent pipe 89 is fully closed, the heating steam stop valve is closed. 46 open. If the feed water heater side vent valve 45 installed in the vent pipe 90 does not prevent the backflow of the heating steam from the feed water heater, the condenser side vent valve 44 installed in the vent pipe 89 is fully opened. The feedwater heater side vent valve 45 installed in the outlet pipe 90 is fully closed, the feedwater heater side vent valve 45 is fully opened at a specified generator output value, and the condenser side vent valve 44 is fully closed.

Next, after confirming that the first stage heater has been ventilated, the second stage heater is ventilated. The heating steam stop valve 10 installed in the steam pipe 52 led to the moisture separation heater 5 is fully opened with the heating steam stop valve 46 installed in the steam pipe 54 fully opened. Thereby, independent operation of the second stage heater can be prevented. Heated steam stop valve 10 Steam pipe 5 after fully opened
2 and the generator output 3
The heating steam control valve 11 is controlled by setting the heating steam control valve 11 to a predetermined set pressure.

When the backflow of the heating steam from the feedwater heater is prevented, the vent valve 15 installed in the vent pipe 83 is fully opened before the heating steam stop valve 10 is opened, and the vent pipe 84 is provided. Condenser side vent valve 14 installed in
After fully closed, the heating steam stop valve 10 is opened.

If the feed water heater side vent valve 15 installed in the vent pipe 83 does not prevent backflow of the heated steam from the feed water heater, the condenser side vent valve 14 installed in the vent pipe 84 The feed water heater side vent valve 15 installed in the vent pipe 83 is fully closed, the feed water heater side vent valve 15 is fully opened at a specified generator output, and the condenser side vent valve 14 is fully closed.

The heated steam pressure gauge 18 flowing through the steam pipe 52
Is a specified value, and the heating steam control valve bypass valve 12 is opened under the condition that the difference from the steam pressure (temperature) generated by the steam generator 1 is small. One way to open it is
After the heating steam control valve bypass valve 12 is opened from the fully closed position to the specified opening and held at that opening for a certain period of time, again opened to a larger specified opening and held at that opening for a certain period of time, after several times Fully open.

As the second means, the valve can be fully opened from the fully closed state to the fully open state by the operation time peculiar to the valve.
As described above, the turbine can be prevented from generating vibration, the damage separating heater can be prevented from spreading, and the moisture separating heater can be set to the reheating operation. In addition, the reheating operation can also be performed by the above operation automatically in addition to the manual operation.
It is possible to have diversity in operation.

Next, a second embodiment of the control method for stopping the reheating operation of the moisture separation heater according to the present invention will be described with reference to FIG. A method of stopping the heating steam of the moisture separation heater, stopping the second stage heater and then stopping the first stage heater to stop the reheating operation of the moisture separation heater will be described.

First, the case where the second-stage heater is stopped will be described. The heating steam control valve bypass valve 12 installed in the steam pipe 52 led to the moisture separation heater 5 is closed. One means for closing is a heated steam control valve bypass valve 1
2 is fully closed from the fully opened position to the specified opening degree, held at that opening degree for a certain period of time, closed again at a smaller specified opening degree, held at that opening degree for a certain period of time, and then fully closed.

As the second means, the valve can be fully closed from the fully open state to the fully closed state by the operation time inherent to the valve.
Thereafter, the heating steam pressure gauge 18 flowing through the steam pipe 52 and the heating steam control valve 11 are controlled by setting the heating steam control valve 11 based on the output 31 of the generator. When the generator output 31 reaches the specified value, the heating steam stop valve 10
Is fully closed. The heating steam control valve 11 is fully closed with the condition that the heating steam stop valve 10 is fully closed .

The feed water heater side vent valve 15 installed in the vent pipe 83 is connected to the condenser side vent valve 14 installed in the vent pipe 84 when the backflow of the heating steam from the feed water heater is prevented. After fully opening the heating steam stop valve 10 and fully closing the feedwater heater side vent valve 15 installed in the vent pipe 83, the feedwater heater side vent valve 15 installed in the vent pipe 83 is connected to the feedwater heater. When there is no prevention of backflow of the heated steam from the heater, the heating steam stop valve 10 is fully closed before the heating steam stop valve 10 is closed, and the heated steam stop valve 10 is closed after the condenser side vent valve 14 installed in the vent pipe 84 is fully opened.

Next, after confirming that the second-stage heater has stopped, the first-stage heater is stopped. The first-stage heater is stopped on condition that the second-stage heater is stopped and the heating steam stop valve 10 is fully closed. The heated steam stop valve 46 installed in the steam pipe 54 is closed. As one means for closing, the heating steam stop valve 46 is closed from full open to a specified opening, held at that opening for a certain period of time, closed again to a smaller specified opening, and held at that opening for a certain period of time. Fully close after several repetitions.

As a second means, the valve can be fully closed from the fully open state to the fully closed state by the operation time peculiar to the valve.
Thereby, independent operation of the second stage heater can be prevented. Feed water heater side vent valve 45 installed in vent pipe 90
When the backflow of the heating steam from the feedwater heater is prevented, the vent valve 45 on the feedwater heater side is fully closed after the heating steam stop valve 46 is fully closed before opening, and the condenser side vent installed in the vent pipe 89 is provided. If there is no backflow of the heating steam from the feedwater heater at the feedwater heater side vent valve 45 installed on the vent pipe 90 with the valve 44 fully opened, install it on the vent pipe 89 before the heating steam stop valve 46 is fully closed. The condenser side vent valve 44 is fully opened, and the feed water heater side vent valve 45 installed in the vent pipe 90 is fully closed.

Next, a third embodiment of the method for operating the moisture separation heater of the present invention will be described with reference to FIG. Installed in a vent pipe 89 to extract non-condensable gas in the heater and prevent partial cooling by draining steam in the heat transfer tube and secure a stable steam amount when the load on the turbine suddenly decreases. The condenser side vent valve 44 is fully opened, and the vent piping 90
Fully closed the feed water heater side vent valve 45 installed in
Prevents supercooling due to the drain inside the heat transfer tube and prevents the damage separation heater from spreading.

Next, a fourth embodiment of the method for operating the moisture separation heater of the present invention will be described with reference to FIG. During turbine load operation, a vent valve is provided to extract non-condensable gas in the heater, prevent partial cooling of the scavenging steam, prevent supercooling by drain in the heat transfer tube, and secure a stable steam amount. When switching between the feedwater heater side and the condenser side, the condenser vent valve 44 installed in the vent pipe 89 is fully opened, and the feedwater heater vent valve 45 installed in the vent pipe 90 is fully closed. When the water heater side vent valve 44 is fully closed and the feed water heater side vent valve 45 installed in the vent pipe 90 is switched to full open, the feed water heater side vent valve 45 is fully opened, and then the condenser side vent valve is set. 44 is fully closed.

The condenser side vent valve 44 installed in the vent pipe 89 is fully closed, the condenser heater side vent valve 45 installed in the vent pipe 90 is fully opened, and the condenser side vent valve 44 is fully opened.
Feed water heater side vent valve 45 installed in vent pipe 90
When the condenser is switched to the fully closed state, the condenser side vent valve 44 is fully opened, and then the feedwater heater side vent valve 45 is fully closed to prevent overcooling of the drain in the heat transfer tube due to the blockage of the vent system to prevent the moisture from flowing. Prevent damage spread of the separation heater.

Next, a description will be given of a fifth embodiment of the method for operating the moisture separation heater according to the present invention. First, a diagram of the overall configuration
6 is shown. The steam generated by the steam generator 1 enters the high-pressure turbine 4 through a steam stop valve 2 and a steam control valve 3 installed in a steam pipe 51, and the exhaust steam of the steam is separated by the moisture separating heaters 5a and 5b. Is heated in the moisture separation heaters 5a and 5b by the steam guided from the steam generator 1 through the steam pipes 52a and 52b and the steam guided from the high pressure turbine 4 through the steam pipes 54a and 54b. The steam flows into the low-pressure turbine 6 through the steam pipe 53, and drives the turbine 6 and the generator 32.

The turbine exhaust steam is condensed in the condenser 7 to be condensed. The condensed water condensed in the condenser 7 is supplied to the feed / recovery pipe 6
The feed water heater 9 is pressurized by the feed water return pump 8 installed in
Then, the temperature is raised by the turbine extracted steam guided from the high pressure turbine 4 through the extraction pipe 71 and sent to the steam generator 1.

On the other hand, the steam branched from the upstream of the steam stop valve 2 passes through the heated steam stop valves 10a and 10b installed in the steam pipes 52a and 52b and passes through the heated steam control valves 11a and 11b or the heated steam control valve bypass. Extracted steam branched from the high-pressure turbine 4 via the valves 12a and 12b and the extracted steam branched from the high-pressure turbine 4 passes through a heated steam stop valve 46 provided in the steam piping 54a and 54b. At b, the high-pressure turbine exhaust steam is heated.

The moisture separation heaters 5a and 5b have a heater and a moisture separator therein, and the heaters include:
Heated steam stop valve 10 for guiding heated steam from steam generator 1
a and b, steam pipes 52a and 52b provided with heated steam control valves 11a and 11b, and heated steam control valve bypass valves 12a and 12b, and steam pipes branched from the high-pressure turbine 4 and provided with heated steam stop valves 46a and 46b. This is a two-stage / 2-sequence configuration that communicates with each of the channels 54a and 54b.

The two-stage heater has a first-stage heater using the extracted steam of the high-pressure turbine 4 as the heating steam and a second heater using the steam generator 1 as the heating steam due to the difference in the enthalpy of the heating steam.
Due to the difference in enthalpy of the heating steam, the second stage heater alone operation in the stopped state of the first stage heater causes damage such as thermal deformation of the moisture separation heaters 5a and 5b due to the difference in enthalpy of the heating steam. It is necessary to operate the second-stage heater while the first-stage heater is in operation.

In the two-series heaters, the steam heated by the heaters flows into the left and right low-pressure turbines, respectively. There is a possibility that a difference may occur and damage such as turbine vibration and thermal deformation may occur, and it is necessary to perform simultaneous operation / stop of two systems.

In the steam turbine plant system configured as described above, a control device 16 is provided to control the operation of the moisture separation heater 5. This control device 1
Reference numeral 6 denotes a heated steam stop valve 1 installed in a steam pipe 52.
0, heating steam control valve 11, heating steam control valve bypass valve 1
2, and includes a control function of the heated steam stop valve 46 installed in the steam pipe 54.

The control device 16 includes a steam pipe 52
Heated steam pressure gauges 18a, b flowing through a, b, steam pipe 5
The low-pressure turbine inlet thermometer 19 flowing through 3a and 3b, the generator output 31 of the generator 32, and the plant state signal 17 are input and used to determine the various control operations.

When operating the moisture separation heater, a heating steam stop valve, a heating steam control valve, a heating steam control valve, a bypass valve are opened, and a heating steam is vented to heat the high-pressure turbine exhaust steam. The plant will be operated. In order to prevent damage to the moisture separation heater from spreading and prevent the turbine from vibrating, the heating steam of the moisture separation heater is passed through the first stage heater in order to perform the reheat operation of the moisture separation heater. Thereafter, the second stage heater ventilation can be achieved by stopping the heating of the high-pressure turbine exhaust steam.

Next, a method for shutting down the operation of the moisture separation heater of the present invention will be described with reference to FIG . A method of operating the moisture separation heater by passing the heating steam of the moisture separation heater through the first stage heater and then through the second stage heater will be described.

First, the case where the ventilation of the first stage heater is started will be described. When ventilating the first-stage heater, the heating steam stop valves 46a and 46b installed in the steam pipes 54a and 54b are opened. One means for opening is a heated steam stop valve 46.
a and b are opened from the fully closed state to the specified opening degree, held at the opening degree for a certain period of time, opened again to a larger specified opening degree, held at the opening degree for a certain period of time, and then fully opened.

As the second means, the valve can be fully opened from a fully closed state to a fully opened state by an operation time peculiar to the valve.

Next, after confirming that the first stage heater has been ventilated, the second stage heater is ventilated. The heating steam stop valves 10a and 10b installed in the steam pipes 52a and 52b guided to the moisture separation heaters 5a and 5b are fully opened with the heating steam stop valves 46a and 46b installed in the steam pipes 54a and 54b fully opened. I do. Thereby, independent operation of the second stage heater can be prevented. After the heated steam stop valves 10a, b are fully opened, heated steam pressure gauges 18a, b flowing through the steam pipes 52a, b, and a generator output 31
The heating steam control valves 11a and 11b are controlled to a predetermined set pressure to perform heating steam pressure control.

Under the condition that the heating steam pressure gauges 18a and 18b flowing through the steam pipes 52a and 52b have specified values and the difference from the steam pressure (temperature) generated by the steam generator 1 is small, the heating steam control valve bypasses. The valves 12a and 12b are opened. One means for opening is a heating steam control valve bypass valve 12a, b
Is opened from the fully closed position to the specified opening, held at that opening for a certain period of time, opened again to a larger specified opening, held at that opening for a certain period of time, and then fully opened. As the second means, it is also possible to make the valve fully open from the fully closed state to the fully open state by the operation time inherent to the valve.

As described above, it is possible to prevent the turbine from vibrating, prevent damage to the moisture separator heater from spreading, and operate the moisture separator heater in reheating operation. In the reheating operation, the above-mentioned operation can be automatically performed in addition to the manual operation, and the operation can be diversified.

A method for stopping the heating steam of the moisture separation heater in the second stage heater and then in the first stage heater to stop the reheating operation of the moisture separation heater will be described. First, a case where the second-stage heater is stopped will be described.

The heating steam control valve bypass valve 1 installed in the steam pipes 52a and 52b led to the moisture separation heaters 5a and 5b
2a and b are closed. As one means for closing, the heating steam control valve bypass valve 12 is closed from full open to a specified opening, held at that opening for a certain period of time, closed again to a smaller specified opening, and held at that opening for a certain period of time. Fully close after repeating the holding several times. As the second means, it is also possible to fully close the valve from the fully open state to the fully closed state by an operation time peculiar to the valve.

Thereafter, the heating steam pressure is controlled by setting the heating steam pressure gauges 18a, b flowing through the steam pipes 52a, b and the heating steam control valves 11a, b based on the output 31 of the generator. When the generator output 31 reaches the specified value, the heating steam stop valves 10a and 10b are fully closed. The heating steam control valves 11a and 11b are fully closed, with the heating steam stop valves 10a and 10b being fully opened.

Next, after confirming that the second-stage heater has stopped, the first-stage heater is stopped. The first-stage heater is stopped on condition that the second-stage heater is stopped and the heating steam stop valves 10a and 10b are fully closed. The heated steam stop valves 46a and 46b installed in the steam pipes 54a and 54b are closed. As one means for closing, the heating steam stop valves 46a and 46b are closed from the fully opened state to the specified opening degree, held at the opening degree for a certain period of time, closed again to a smaller specified opening degree and maintained at the opening degree for a certain period of time. Fully close after repeating the holding several times. As the second means, it is also possible to fully close the valve from the fully open state to the fully closed state by an operation time peculiar to the valve. Thereby, independent operation of the second stage heater can be prevented.

As described above, it is possible to prevent the turbine from vibrating, prevent damage to the moisture separator heater from spreading, and operate the moisture separator heater in reheat operation. In the reheating operation, the above-mentioned operation can be automatically performed in addition to the manual operation, and the operation can be diversified.

As described above, by operating / stopping the moisture separation heater by heating / ventilation / interruption of the heating steam, it is possible to prevent the moisture separation heater from being damaged and prevent the steam turbine from vibrating. I can do it.

[0059]

As described above, according to the steam turbine operating method of the present invention, when the operation of the steam turbine is stopped, the heating of the steam discharged from the high-pressure turbine by the moisture separating heater is gradually reduced. Therefore, the steam temperature change rate of the low-pressure turbine is small, and the generation of vibration of the low-pressure turbine can be sufficiently suppressed.

[Brief description of the drawings]

FIG. 1 is a system diagram of a steam turbine plant for explaining a method of operating a steam turbine of the present invention.

FIG. 2 is a moisture separation heater ventilation logic diagram for explaining the operation method of the steam turbine of the present invention.

FIG. 3 is a logic diagram for stopping a moisture separation heater for explaining a method of operating the steam turbine of the present invention.

FIG. 4 is a logic diagram of an operation of a moisture separation heater for explaining a method of operating the steam turbine of the present invention.

FIG. 5 is a moisture separation heater operation logic diagram for explaining the operation method of the steam turbine of the present invention.

FIG. 6 is a system diagram of a steam turbine plant for explaining a method of operating the steam turbine of the present invention.

FIG. 7 illustrates a method of operating the steam turbine of the present invention.
FIG. 4 is a logic diagram of the operation of a moisture separation heater for the purpose of the present invention.

FIG. 8 illustrates a method of operating the steam turbine of the present invention.
FIG. 4 is a logic diagram of a moisture separator heater vent / stop for the present invention.

[Explanation of symbols]

1 steam generator, 2 steam stop valve, 3 steam control valve, 4
... High pressure turbine, 5 ... Humidity separation heater, 6 ... Low pressure turbine, 7 ... Condenser, 8 ... Feedback pump, 9 ... Feedwater heater,
10: heated steam stop valve, 11: heated steam control valve, 12:
Heating steam control valve bypass valve, 14 … Condenser side vent valve,
15: feed water heater side vent valve, 16: control device, 17,
46: Heated steam stop valve.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideaki Kaneda 3-1-1 Sachimachi, Hitachi-shi, Ibaraki Hitachi, Ltd. Hitachi Plant (72) Inventor Takuji Nishinomiya 3-2-2 Sachimachi, Hitachi-shi, Ibaraki No. 1 Hitachi Engineering Co., Ltd. (56) References JP-A-59-77012 (JP, A) JP-A-61-15008 (JP, A) JP-A-61-59105 (JP, A) 184003 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F01K 7/22 F01K 7/38 102

Claims (4)

(57) [Claims] 1. A high-pressure turbine using steam generated by a steam generator as a driving source, a second-stage heater using a part of inlet steam of the high-pressure turbine as a heating source, and a part of high-pressure turbine extracted steam. A moisture separation heater for reheating the high pressure turbine exhaust by a first stage heater as a heating source, a low pressure turbine driven by the reheated steam, and a high pressure turbine inlet steam heating of the moisture separation heater A heating steam stop valve for shutting off steam, a high pressure turbine inlet steam heating steam control valve for adjusting the amount of steam heating steam at the high pressure turbine inlet, a heating steam stop valve for shutting off high pressure turbine bleed steam heating steam, and a moisture separation heater Condenser-side vent valve, feedwater heater-side vent valve to ensure stable steam flow, heater drain tank and heater drain tank reservoir for retaining the drain of heated steam from the moisture separation heater Heater-side level control valve for controlling bell, condenser-side level control valve and the above-mentioned heating steam stop valve, heating steam control valve, heating steam control valve bypass valve, condenser side vent valve, heater side vent valve, heater In a method for operating a steam turbine comprising a drain tank heater-side level adjustment valve and a control device for controlling a condenser-side level adjustment valve, when stopping the operation of the moisture separation heater, first the second stage heating is performed. To shut off the heating steam so as to stop the first stage heater, and then to start the operation of the moisture separation heater, vent the first stage heater,
The method for operating a steam turbine, further comprising operating the second stage heater to perform ventilation. 2. The steam turbine operating method according to claim 1, wherein during a transient operation such as a sudden decrease in the load of the turbine, the vent system is forcibly switched from a feed water heater side to a condenser side. 3. When the discharge destination of the vent system is switched between the feed water heater and the condenser during the load operation of the turbine, the vent valve on the side to be switched is opened after confirming that the switching vent valve is opened. 2. The method for operating a steam turbine according to claim 1, wherein the vent valve on the other side is closed. 4. A high-pressure turbine, a low-pressure turbine and a moisture separator / heater, wherein the moisture separator / heater is installed in two lines, one each for left and right inlet steam of the low-pressure turbine, and discharge steam from the high-pressure turbine is provided. re heated part of the inlet steam of the high pressure turbine by the moisture separator heater as a heat source, method of operating a steam turbine is formed to drive the low pressure turbine at the reheat steam, the When starting the operation of the moisture separation heater, the first stage heating
The two heaters are ventilated simultaneously and then the second stage heater
When the operation is stopped at the same time, the second stage heating
The two heaters are stopped at the same time, and then the first heater
A method for operating a steam turbine, wherein the steam is stopped simultaneously to shut off heated steam .