JPS5846645B2 - Turbine warm-up method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for warming up a turbine, particularly a high-intermediate pressure integrated turbine, at startup.

It is well known that warming up of a turbine is generally carried out to preheat the turbine rotor to a temperature above the transition temperature when the turbine is started, to prevent the risk of brittle fracture, and to shorten the start-up time.

Therefore, the turbine is warmed up especially during cold start-up.

However, in conventional turbine warming-up methods and devices, the high-pressure turbine is warmed up, but the intermediate-pressure turbine is not warmed up.

A typical example thereof will be explained with reference to FIG. 1. Reference numerals 1 and 2 are a high pressure turbine and an intermediate pressure turbine of an integrated high and intermediate pressure turbine, and a comb tooth portion 17 is provided between the two.

3 is a low-pressure turbine; 4 is a condenser connected to the comb portion 17 via an emergency blowdown valve 19 (hereinafter referred to as an emergency valve) for preventing overheating of the turbine; 5 and 6 are connected to the high-pressure turbine 1; The main steam stop valve and steam control valves 11 and 12 provided in the main steam lead pipe 7 connected to the intermediate pressure turbine 2
These are the reheat steam stop valve and ink sect valve provided in the piping 9 connected to.

10 is a low-temperature reheat pipe connected to the high-pressure turbine 1; 13 is a relatively low-temperature, low-pressure steam header connected to the low-temperature reheat pipe 10 via a pipe 13c and a pressure regulating valve 16; 15 is a steam header connected to the turbine via a pipe 13b. Piping 1 is connected to the shaft sealing parts 1 to 3.
3a and a grand steam regulator connected to the steam header 13 via valve 14, 23 is a crossover pipe connecting intermediate pressure turbine 2 and low pressure turbine 3, and 24 is connected to the shafts of turbines 1 to 3 via piping 24a. A ground steam condenser connected to the enclosure, which maintains a slight vacuum to isolate the inside and outside of the turbine.

The emergency valve 19 has a rod 19 attached to the valve body 19a1 and the valve body 19a.
Piston 19b and spring 19c connected via d
The air header 20 is connected to the air header 20 via the piping 20a, 20c and the switching valve 22, and the comb tooth portion 17 is connected to the air header 20 via the piping 18.
and are connected to the condenser 4 via piping 20d.

This emergency valve 19 is opened and closed by supplying and shutting off air from the air header 20.

In other words, if the air is shut off, the valve body 19a will act as a spring 19c.
If the force of the spring opens and air is supplied, the air pressure will be 1
The valve body 19a is closed because the piston 19b is pressed against the force of the valve body 9c.

The air switching valve 22 cuts off the air supply to the emergency valve 19 when the intercept valve 12 is fully closed, and supplies air to the emergency valve 19 when the intercept valve 12 is fully open.

Since the turbine is warmed up during turbine trip, the main steam stop valve 5, the steam control valve 6, and the reheat steam stop valve 11 are used to warm up the turbine.
And the intercept valve 12 is in a fully closed state.

By fully opening the intercept valve 12, the emergency valve 19 is kept fully open.

On the other hand, the low-temperature, low-pressure steam in the steam header 13 is led to the grand steam regulator 15 via a pipe 13a and a valve 14, and after being adjusted to a specified steam pressure by the regulator 15,
It is supplied to the ground section of each turbine 1 to 3 through.

A portion of the supplied steam is recovered to the gland steam condenser 24 via the pipe 24a, and the remainder is guided into the turbine.

Once the turbine shaft seal is sealed as described above, the degree of vacuum in the condenser 4 is increased to an appropriate value.

Thereafter, the valve 16 is gradually opened, and steam from the steam header 13 is introduced into the high-pressure turbine 1 via the pipe 13c1 valve 16 and the low-temperature reheat pipe 10 to warm it up.

Then, the valve 8 is opened to adjust the pressure inside the high-pressure turbine 1 to an appropriate level, and in this state, the rotor is warmed up until the temperature becomes optimal.

During this time, the steam leaking from the abolished turbine 1 is transferred to the comb tooth section 17.
The water is recovered to the condenser 4 via the pipe 18, the emergency valve 19, and the pipe 20.

Therefore, leakage steam from the high pressure turbine 1 is transferred to the intermediate pressure turbine 2.
The intermediate pressure turbine 2 is not warmed up because there is almost no inflow into the intermediate pressure turbine 2.

As described above, the high-pressure turbine 1 is warmed up by steam, but the intermediate-pressure turbine 2 is not warmed up, so high-temperature and high-pressure steam is introduced into the high-pressure and intermediate-pressure turbines during turbine ventilation.

As a result, thermal stress in the high-pressure rotor section is reduced due to a reduction in the amount of metal mismatch, and the life consumption is also reduced, so the life is extended.

On the other hand, the amount of metal mismatch in the medium pressure rotor section is large,
In contrast to the high-pressure rotor section, thermal stress increases, so the lifetime consumption also decreases, resulting in a shortened lifespan and reduced reliability and safety.

In particular, there has been an increase in the number of cold engine starts, but with the warm-up method described above, the warm-up effect is significantly reduced.
There are disadvantages in that it is not possible to extend life, improve reliability, and improve safety.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks and provide a method and apparatus for simultaneously warming up a high-pressure turbine and an intermediate-pressure turbine reliably and economically. This is characterized in that the intermediate pressure turbine is warmed up by pressurizing steam into the intermediate pressure turbine through a comb tooth section provided between the turbine and the turbine.

A warm-up device that is distantly related to the above purpose includes a comb tooth section provided between the high pressure turbine and the intermediate pressure turbine of the high and intermediate pressure integrated turbine, an emergency blowdown valve connected to the comb tooth section, and the emergency blowdown valve connected to the comb tooth section. It is characterized by comprising a switching valve and a switching device provided in a thread path connecting a down valve and a pressure source.

An embodiment of the present invention will be described below with reference to the drawings.

Among the symbols shown in FIGS. 2 and 3, the same symbols as those shown in FIG. 1 indicate the same parts.

In FIG. 2, 19 is an emergency blowdown valve consisting of a valve body 19a, a piston 19b connected to the valve body 19a via a rod 19d, and a spring 19c acting on the piston 19b. The comb tooth portion 17 provided between the intermediate pressure turbine 1 and the intermediate pressure turbine 2 is connected to the condenser 4 via a pipe 20a, and to the switching device 21 via a pipe 20c.

A switching valve 22 is connected to the air header 20 via a pipe 20a and to the switching device 21 via a pipe 20b.

The rest of the structure is the same as the conventional example (FIG. 1), so drawings and explanations will be omitted.

An electromagnetic three-way switching valve shown in FIG. 3 is used as an example of the switching device 21, and the switching valve 21 is operated by a switch 25 connected by a wiring 25a.

That is, when the switch 25 is turned on, the switching valve 21 is energized and switched to communicate the pipes 20e and 20c.

Conversely, when the switch 25 is turned off, the switching valve 21 is demagnetized and switched to communicate the pipes 20c and 20b.

Therefore, when the switch 25 is turned on to warm up the turbine, the air in the air header 20 is supplied to the piston chamber 19e of the emergency blowdown valve 19 via the piping 20e, the electromagnetic three-way switching valve 21, and the piping 20c, and the air is supplied to the piston chamber 19e of the emergency blowdown valve 19. The valve element 19a of the emergency blowdown valve 19 is forcibly fully closed by overcoming the force.

For this reason, leaked warm-up steam from the high-pressure turbine 1 is prevented from flowing into the condenser 4, and the steam is pressurized into the intermediate-pressure turbine 2, so that the intermediate-pressure turbine 2 is warmed up.

If the switch 25 is turned off when the intermediate pressure turbine 2 has been warmed up as described above, the electromagnetic three-way switching valve 21 is switched and the pipes 20c and 20b are communicated with each other.

Therefore, the air in the piston chamber 191 passes through the piping 20c1, the electromagnetic three-way switching valve 21, the piping 20b, and the switching valve 22, and is discharged to the atmosphere from the piping 20f. It is fully opened by.

Therefore, leaked steam from the warm-up steam of the high-pressure turbine 1 is introduced into the condenser 4 via the comb portion 11, the pipe 18, the emergency blowdown valve 19, and the pipe 20d.

On the other hand, during turbine load operation, the intercept valve 12 is fully opened, so the switching valve 22 communicates the pipes 20a and 20b, so the air in the air header 20 is transferred to the pipe 20a,
Piston chamber 1 of emergency blowdown valve 19 via switching valve 22, piping 20b, electromagnetic three-way switching valve 21, and piping 20c
97, and the valve body 19a is fully opened.

In addition, when the turbine trips or the load is cut off, the electromagnetic three-way switching valve 21 is demagnetized and the pipes 20b and 20c are in communication, but the switching valve 226 and the intercept valve 12 are fully opened to communicate the pipes 20a and 2of. Therefore, the air in the air header 20 is not supplied to the emergency blowdown valve 19, so the valve body 19a is fully opened.

That is, even if the electromagnetic three-way switching valve 21 is installed, there is no problem in normal operation.

As described above, in this embodiment, the emergency blowdown valve 19 is forcibly fully closed by the electromagnetic three-way switching valve 21 and the switching valve 22, thereby leaking warm-up steam from the high-pressure turbine 1 to the intermediate-pressure turbine 2. I pressed it in and let it warm up.

As explained above, according to the present invention, by introducing leaked warm-up steam from the high-pressure turbine into the intermediate-pressure turbine as warm-up steam through the comb teeth, the amount of metal mismatch during startup can be reduced. Since thermal stress can be reduced, the lifespan, reliability and safety of the turbine can be improved.

In particular, warming up the intermediate pressure turbine during cold startup can increase the rotor temperature, reduce the amount of metal mismatch, and shorten the startup time of the turbine.

Therefore, it is possible to save fuel for boilers and the like, so the economic effect is significant.

[Brief explanation of drawings]

Fig. 1 is a warm-up system diagram of a conventional high-medium pressure integrated turbine, Fig. 2 is a system diagram showing an example of a warm-up method for a high-medium pressure integrated turbine according to the present invention, and Fig. 3 is a system diagram used in the present invention. FIG. 2 is a diagram illustrating an example of a switching device. 1...High pressure turbine, 2...Intermediate pressure turbine, 17...Comb tooth portion, 19...Emergency blowdown valve, 20...・Pressure source, 21...
...Switching device, 22...Switching valve.

Claims (1)

[Claims] 1. In a method for warming up a turbine at the time of starting a high- and intermediate-pressure integrated turbine, a comb-teeth portion is provided between the high-pressure turbine and the intermediate-pressure turbine, and the steam flowing from the comb-teeth portion to the condenser is heated. A method for warming up a turbine, characterized in that steam is forced into the intermediate pressure turbine through the comb teeth by blocking the flow, thereby warming up the intermediate pressure turbine. 2. A comb tooth section provided between the high pressure turbine and the intermediate pressure turbine of the high and intermediate pressure integrated turbine, an emergency blowdown valve connected to the comb tooth section, and a thread connecting the emergency blowdown valve and the pressure source. It consists of a switching valve and a switching device installed in the airway, and an emergency flow down valve is inserted between the comb teeth and the condenser.
A turbine warm-up island characterized by having an interfering structure that closes, closes, and opens, respectively, during blowdown.