JPH0814010A - Power generation device of reheat condensing steam turbine - Google Patents

Abstract

PURPOSE:To prevent the abnormal heating of a blade to be damaged due to the fanning loss of the blade of a high-pressure turbine at the time of no-load running direct after load cutoff or of turbine stop and a stop process. CONSTITUTION:This device is provided with a drain valve 18 opened by a signal outputted from a comparator 21 when a detected load in a load detector 20 is inputted and the detected load is zero, and a nonreturn valve 22 quickly closed by the operation of a fluid pressure cylinder device 23 by the signal in a low-temperature reheat steam system 7. The nonreturn valve 22 is quickly closed via the fluid pressure cylinder device 23 by the signal from the comparator 21 at the time of no-load running to cut off the inside of a high-pressure turbine 1 from a reheater 5, and while the drain valve 18 to be communicated with a condensor 4 is opened to quickly lower the inside pressure of the high- pressure turbine 1 to lower the fanning loss of a blade.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reheat recovery steam turbine power generation facility including a reheat recovery steam turbine and a generator for generating power by driving the turbine.

[0002]

2. Description of the Related Art A steam turbine is driven by a main steam supplied from a boiler and a reheat steam supplied from a reheater to drive a generator connected to the steam turbine to generate reheat. Figure 2 as a steam turbine power generation facility
What is shown in the system diagram of is known. In FIG. 2, a high-pressure turbine 1 driven by main steam from a boiler (not shown), a low-pressure turbine 2 driven by reheat steam from a reheater 5, and a generator 3 are directly connected via respective rotary shafts. Has been done. A condenser 4 is connected to the exhaust port of the low-pressure turbine 2.

The reheater 5 has its steam inlet via the low temperature reheat steam system 7 to the exhaust port 6 of the high pressure turbine 1, and its steam outlet via the high temperature reheat steam system 8 to the low pressure turbine 2. It is connected to the steam inlet. The high temperature reheat steam system 8 is provided with a reheat stop valve 9 and an intercept valve 10. The main steam supply system 13 is connected to the steam inlet of the high-pressure turbine 1 and a boiler (not shown), and includes a main steam stop valve 14 and a steam control valve 15.

The drain discharge system 17 is provided so as to be connected to the middle of the blade stage of the high-pressure turbine 1 and the condenser 4, and the drain valve 1
8 is provided. The load detector 20 detects the electric power supplied from the generator 3 to the external load, that is, the load. Comparator 2
1 receives the signal of the load detected by the load detector 20 and outputs a signal for opening the drain valve 18 when the detected load is zero.

With such a configuration, during the normal operation of the reheat steam recovery turbine generator, the main steam stop valve 14 of the main steam supply system 13 and the reheat stop valve 9 of the high temperature reheat steam system 8 are opened to open the boiler. When the main steam is supplied from the main steam to the main steam supply system 13, the high pressure turbine 1 is driven by the main steam, and the exhaust steam discharged from the exhaust port 6 of the high pressure turbine 1 passes through the low temperature reheat steam system 7 and the reheater 5 Flow into. Then, the exhaust steam is reheated in the reheater 5 to raise the temperature, and the raised reheat steam flows into the low pressure turbine 2 through the high temperature reheat steam system 8 to drive the low pressure turbine 2. Then, the exhaust steam of the low-pressure turbine 2 flows into the condenser 4 to be cooled and condensed, and the condenser 4
The inside pressure is maintained below atmospheric pressure. At this time, the generator 3
Outputs electric power commensurate with the work of steam in the high-pressure turbine 1 and the low-pressure turbine 2 and supplies the electric power to an external load.

By the way, the load detected by the load detector 20 becomes zero during no-load operation immediately after the load is cut off in the reheat recovery steam turbine power generation facility or during no-load operation when the turbine is stopped. In this case, a signal is output from the comparator 21 to which the detected load signal is input when the detected load is zero, and the drain valve 18 is opened by this signal. As a result, the steam from the reheater 5 flows back through the low temperature reheat steam system 7 from the exhaust port 6 through the blade section of the high pressure turbine 1, and then flows into the condenser 4 via the drain discharge system 17. At this time, the steam from the reheater 5 which flows backward through the blade stages cools the blades to prevent heating due to the stirring loss of the blades.

[0007]

Due to the churning loss of the blades of the blade stage of the high-pressure turbine 1, during the no-load operation immediately after the load removal of the reheat recovery steam turbine power generation facility or during the no-load operation and the shutdown process when the turbine is stopped. In order to prevent heating, the steam of the reheater is made to flow backward from the exhaust port of the high-pressure turbine, and is made to flow from the drain valve 18 to the condenser 4 via the drain discharge system 17. However, since the amount of accumulated steam in the reheater 5 is large,
Even if the drain valve 18 is opened, the internal pressure in the high-pressure turbine cannot be rapidly reduced, and the no-load operation and the turbine stop will be performed in the state where the internal pressure is high. There is a problem that the blade is abnormally heated due to the loss and the blade is damaged.

An object of the present invention is to carry out no-load operation immediately after the load is cut off, no-load operation when the turbine is stopped, and the stop process.
An object of the present invention is to provide a reheat recovery steam turbine power generation facility capable of preventing abnormal heating due to agitation loss of blades of a high-pressure turbine.

[0009]

In order to solve the above-mentioned problems, according to the present invention, a high-pressure turbine into which main steam flows to perform work, and a reheater for reheating exhaust steam from the high-pressure turbine are provided. , A low-pressure turbine into which reheated steam from this reheater flows to perform work, a condenser that cools and condenses exhaust steam from this low-pressure turbine to maintain the pressure below atmospheric pressure, and the high pressure and low pressure A generator that converts the work by steam in the turbine into electric power and supplies it to an external load, and a drain discharge system equipped with a drain valve that extracts the drain from the middle of the high pressure turbine blade stage and flows it into the condenser. In a reheat steam condensing turbine power generation facility equipped with, a valve for rapid closing provided in a low temperature reheat steam system connected to an exhaust port of a high pressure turbine and a steam inlet of a reheater, and a generator to supply to an external load Load detection to detect power And vessels, it is input detected load signal of the load detector is assumed and a comparator for outputting a signal to the valve to open and Kyu閉 actuating the drain valve when the detected load is zero in the closed.

In the above description, the valve that performs the rapid closing operation is a check valve and a fluid pressure that applies an opening operation force to the valve element when the valve is opened and does not apply a closing operation force to the valve element when the valve is closed. And a signal from the comparator is input to the fluid pressure cylinder device.

[0011]

[Operation] A high-pressure turbine driven by main steam, a reheater for reheating exhaust steam of this turbine, a low-pressure turbine driven by reheat steam from the reheater, and cooling of exhaust steam of this turbine , In a reheat steam condensing turbine power generation facility equipped with a condenser that condenses and holds the pressure below atmospheric pressure, and a generator that converts steam work in the high-pressure and low-pressure turbines into electric power The output power of the generator, that is, the detected load signal that detects the load is input from the comparator when a signal is output when the detected load becomes zero,
With this signal, the drain valve provided in the drain discharge system that extracts the drain from the middle of the blade of the high pressure turbine and flows it into the condenser is opened, and the exhaust port of the high pressure turbine and the steam inlet of the reheater are opened. Since the high-pressure turbine inside and the reheater are disconnected by rapidly closing the valve that is provided for the low-temperature reheat steam system to be rapidly closed, the drain valve of the drain discharge system connected to the condenser is opened. Due to this, the internal pressure of the high-pressure turbine drops sharply. Therefore, the stirring loss of the blade is reduced, and abnormal heating of the blade can be prevented.

The aforesaid quick closing valve is provided with a fluid pressure cylinder device to hold the valve body open by applying an opening operation force to the valve body when the valve is open, while closing the valve body when the valve is closed. A non-return valve that is closed by its own weight without applying operating force.By inputting the signal from the comparator to the fluid pressure cylinder device, the non-return valve is closed and the inside of the high-pressure turbine is separated from the reheater. .

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of a reheat steam recovery turbine power generation facility according to an embodiment of the present invention. In FIG. 1, the same parts as those in the conventional example of FIG. 1 is different from the conventional example of FIG. 2 in that the low-temperature reheat steam system 7 connected to the exhaust port 6 of the high-pressure turbine 1 and the steam inlet of the reheater 5 is a valve that is rapidly closed by a signal from a comparator 21. , Check valve 22 as this valve and check valve 2
That is, a valve including a fluid pressure cylinder device 23 operated by air pressure or hydraulic pressure as an operation device for operating 2 is provided. Here, the piston rod of the fluid pressure cylinder device 23 and the valve shaft of the valve body of the check valve 22 are connected via a crank, and when the check valve 22 is opened, a valve for holding the valve body open is provided. An opening moment sufficient to maintain the opening of the valve body is given to the shaft through a crank by the fluid pressure cylinder device 23, and when the check valve 22 is closed, the opening moment is set to zero and the check valve 22 is checked by its own weight. The valve 22 is closed. The signal from the comparator 21 is input to the fluid pressure cylinder device 23, and the check valve 22 is closed.

With such a configuration, the check valve 22 provided in the low temperature reheat steam system 7 during normal operation of the reheat steam recovery turbine power generation facility is operated by operating the fluid pressure cylinder device 23 by air pressure or hydraulic pressure. An opening moment is applied to the valve shaft of the valve body of the valve 22, and the valve body is maintained in the open state.
Therefore, the exhaust steam of the high-pressure turbine 1 flows into the reheater 5 via the check valve 22 in the open state, is reheated in the reheater 5, and the normal operation is performed.

By the way, the load detected by the load detector 20 becomes zero during the no-load operation immediately after the load is cut off or during the no-load operation and the stopping process when the turbine is stopped. As a result, a signal is output from the comparator 21 to which the detected load is input and is input to the fluid pressure cylinder device 23. By inputting this signal,
Since the opening moment of the fluid pressure cylinder device 23 is set to zero, the check valve is rapidly closed due to the weight of the valve body.
Further, the drain valve 18 is opened by the signal from the comparator 21.

By rapidly closing the check valve 22 as described above, the inside of the high-pressure turbine 1 and the reheater 5 are separated from each other and the condenser 4 is also separated.
The internal pressure of the high-pressure turbine 1 is rapidly reduced by opening the drain valve 18 that is communicated with the valve. Therefore, during no-load operation immediately after the load is cut off or during no-load operation and stop process when the turbine is stopped, the blade stage is closed. The stirrer loss of the blade is reduced, and abnormal heating of the blade can be prevented.

[0017]

As is apparent from the above description, according to the present invention, the valve having the above-mentioned construction is used to perform a rapid closing operation in the low temperature reheat steam system, and a valve including a fluid pressure cylinder device and a check valve. By providing the above, the valve is rapidly closed by a signal from the comparator during the no-load operation or the turbine stop process, and the drain valve of the high pressure turbine is opened.
The inside of the high-pressure turbine and the reheater are separated from each other, so that the internal pressure of the high-pressure turbine is independently lowered, and abnormal heating due to agitation loss of the blades of the high-pressure turbine can be prevented.

[Brief description of drawings]

FIG. 1 is a system diagram of a reheat steam recovery turbine power generation facility according to an embodiment of the present invention.

[Fig. 2] System diagram of a conventional reheat steam recovery turbine power generation facility

[Explanation of symbols]

 1 High-pressure turbine 2 Low-pressure turbine 3 Generator 4 Condenser 5 Reheater 18 Drain valve 20 Load detector 21 Comparator 22 Check valve 23 Fluid pressure cylinder device

Claims (2)

[Claims] Claim: What is claimed is: 1. A high-pressure turbine into which main steam flows to perform work, a reheater to reheat exhaust steam from the high-pressure turbine, and reheat steam from the reheater to perform work. The low-pressure turbine, a condenser that cools and condenses the exhaust steam from the low-pressure turbine to maintain the pressure below atmospheric pressure, and the work by steam in the high-pressure and low-pressure turbines is converted into electric power and supplied to an external load. In the reheat steam condensing turbine power generation facility including a generator that operates and a drain discharge system that includes a drain valve that extracts drain from a blade section in the middle of the high-pressure turbine and flows into the condenser, The valve that is installed in the low-temperature reheat steam system that connects the steam inlet of the reheater and that operates rapidly, the load detector that detects the power supplied from the generator to the external load, and the load detected by the load detector are When it is zero, the drain valve is opened. The valve operating finely Kyu閉 and a comparator for outputting a signal to close feature to reheat condensing steam turbine power generation facilities. 2. The valve according to claim 1, wherein the valve that is rapidly closed is a check valve, and when the valve is opened, an opening operation force is applied to the valve body, and when the valve is closed, the valve body is closed. A reheat recovery steam turbine power generation facility comprising a fluid pressure cylinder device that does not apply an operation force, and a signal from a comparator is input to the fluid pressure cylinder device.