JPH02308903A - Prewarming system of steam turbine - Google Patents

Abstract

PURPOSE:To precisely control auxiliary steam for prewarming in a harmonious state by open-close-switch-controlling a stop valve in a uniform quantity when a comparative output signal between a detected pressure signal and a pressure setting signal of auxiliary steam. CONSTITUTION:Auxiliary steam generated from an auxiliary steam generator 21 is supplied to a high pressure turbine 11 through a stop valve 30 and the temperature and the pressure of the high pressure turbine 11 are raised. The supply pressure of auxiliary steam is detected by a pressure detector 24 here, and this detected pressure signal is compared with the pressure setting signal of pressure setters 36a and 36b and comparators 35a and 35b of control circuits 33 and 34. Then, when the output signal of the comparators 35a and 35b continues for a specific time, the stop valve 30 is controlled to open or to close by a specific quantity. Consequently, auxiliary steam of a specific pressure is supplied at a specific temperature to the high pressure turbine 11 and prewarming of the high pressure turbine 11 is carried out. Accordingly, it is possible to precisely control auxiliary steam for prewarming, which is low in the pressure change, in a harmonious state with the stop valve 30.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a steam turbine pre-warming device, and particularly to a steam turbine pre-warming device in which a high-pressure turbine or the like is pre-warmed with auxiliary steam. This invention relates to a warming device.

(Prior art) Generally, when starting a steam turbine, there is a temperature difference between the temperature of the driving steam supplied to the high-pressure turbine and the temperature of the turbine's metal parts such as the casing and rotor, which causes thermal stress in the casing etc. . This thermal stress is particularly large when the steam turbine is stopped for a long time and then restarted, and if the steam turbine is started in the presence of this thermal stress, the life of the casing, rotor, etc. will be shortened.

Therefore, pre-warming is performed to supply auxiliary steam to steam turbines, etc. to reduce the temperature difference between the temperature of the driving steam and the temperature of metal parts such as the casing, to prevent thermal stress from occurring during startup. Ru.

This pre-warming is normally carried out using the method shown in FIG. That is, the steam turbine plan] is the steam turbine plan.
[0] A high-pressure turbine 11 and an intermediate-pressure/low-pressure turbine 12 connected thereto are provided. This boiler 1
The high temperature steam generated by the main steam pipe] 3, the control valve 1
4 to the high pressure turbine]1, and the rotor]
Used for high speed rotation of 5. The steam that has been subjected to work by the rotor 15 has a low pressure and a low temperature, and is sent to a reheater 17 via a low temperature reheating pipe 16 to be reheated. This reheated steam is further supplied to the medium-pressure/low-pressure turbine 12 etc. through the high-temperature reheat pipe [8] and the intercept valve [9], and after doing work in the medium-pressure/low-pressure turbine 12, it is transferred to a condenser (not shown). The water is condensed in the water.

Low temperature] 1f heat tube 1 near the exhaust port of the high-pressure turbine
6 is connected to an auxiliary steam generator 2 for pre-warming via an auxiliary steam supply pipe 20. The auxiliary steam supply pipe 20 is separately provided with a first valve 22 for cutting off the supply of auxiliary steam, and a regulating valve 23 for controlling the supply pressure of the auxiliary steam.

In addition, the auxiliary steam supply pipe 20 is equipped with a pressure detector 2 for detecting the auxiliary steam pressure in the vicinity of the high-pressure turbine.
4 is taken] is kicked. The pressure detection signal of this pressure detector 24 is sent to the pressure control device 25, and this detected pressure signal is, for example, 7.0 gauge pressure (hereinafter referred to as "cage pressure").
If the detected pressure signal is lower than 6.8 ATG, the regulating valve 23 is controlled to open, and the auxiliary steam pressure supplied to the high pressure turbine 1 is controlled. is controlled to a predetermined pressure. Furthermore, the rotor 5 of the high pressure turbine 1 is provided with a temperature detector 26 for detecting its temperature. The temperature detection im number of this temperature sensor 14'1 device 26 is controlled by the temperature control device 27.
If the detected temperature signal 1 is below 150°C, stop valve 22 is opened, auxiliary steam is supplied to the high pressure turbine, and if the detected temperature signal is 158°C or above, stop valve 2 is opened.
2 is closed, and auxiliary steam supplied to the high-pressure turbine 11 is cut off.

Reference numerals 28 and 29 are drain valves installed between the high-pressure turbine 11 and the reheater 7 and between the reheater 17 and the intercept valve 9 to drain drain water generated during pre-warming. It is something that is discharged.

This pre-warming of the steam turbine will be explained. This pre-warming is generally performed at the portion where the temperature difference between the driving steam and the steam turbine is greatest, that is, one high-pressure turbine.

When performing this pre-warming, first
4 and the intercept valve 19 are closed, and the main steam supplied from the boiler 10 to the high pressure turbine 11 is stopped.

Next, the pressure control device 25 and temperature control device 27 are operated. First, the temperature of the rotor tacho 5 is detected by the temperature detector 26, and the detected temperature signal is sent to the temperature control device 27. Since this detected temperature signal is a low temperature at the time of excitation, 15
Is it below 0'C? An opening operation (Fr number) is sent to the stop valve 22 by the M□I degree control device 27, and this stop valve 22 is opened.

On the other hand, the auxiliary steam pressure supplied to the high pressure turbine 1 is detected by the pressure detector 24, and the detected pressure signal is sent to the pressure control device 25. This IQ output positive pressure signal is 6.8 ATC because auxiliary steam is not being supplied to the high pressure turbine 1;
5 sends an opening operation signal to the regulating valve 2B, and this regulating valve 2
3 open control is performed.

By controlling the opening of the regulating valve 23 and opening the stop valve 22,
Auxiliary steam is supplied from the two auxiliary steam generators to the high-pressure turbine]. This (Jl, supplementary steam) is first cooled by low-temperature parts such as the casing of the high-pressure turbine 11 and the rotor 15, so it becomes 1.1 non-water and drain valve 28.
29 will be rejected. After a short period of time, the temperature of the caisson, etc. of the pressure turbine rises, the amount of auxiliary steam draining decreases, and the auxiliary steam pressure approaches 6.8 ATG; Bpi pressure. This state continues for a while until the pressure of the high pressure turbine 11 reaches 7.0 (ATG) and the temperature of the rotary tacho 5, etc. reaches about 150°C.

When the temperature of the rotor tacho 5, etc. reaches 158° C. or higher, the temperature control circuit 27 is controlled by the temperature signal from the temperature detector 26, the stop valve 22 is closed, and auxiliary steam to be supplied to the high pressure turbine 1 is supplied. Prewarming of the high pressure turbine 11 is completed.

After pre-warming is completed, the regulator valve 14 and the intercept valve are opened, and the high pressure turbine is removed from the boiler 1o.]
Main steam is supplied to the high pressure turbine 11 and the high pressure turbine 11 etc. start operating.

(Problem to be Solved by the Invention) Pre-warming for high-pressure turbine firing involves supplying high-pressure auxiliary steam generated from an auxiliary steam generator to a high-pressure turbine, etc. while controlling it with a regulating valve and a stop valve, and then supplying high-pressure auxiliary steam generated from an auxiliary steam generator to a high-pressure turbine, etc., to a predetermined pressure such as a casing, etc. The temperature is adjusted to the specified temperature.

In order to effectively perform this prewarming, it is necessary to maintain the high pressure auxiliary steam at an accurate value. For example, if the auxiliary steam pressure of a high-pressure turbine or the like is too low, prewarming will be delayed, and if it is too high, the thrust bearing of the turbine will be adversely affected.

However, in general, in this pre-warming, most of the auxiliary steam supplied to the high-pressure turbine etc. is initially cooled by the high-pressure turbine etc. and turned into drain water, and it takes time to reach the specified pressure even if the regulating valve is fully opened. It takes. Furthermore, as the temperature of the casing, rotor, etc. rises, the auxiliary steam pressure gradually increases, and the regulating valve may be slowly throttled in response to the auxiliary steam pressure.

On the other hand, since the regular regulating valve captures pressure fluctuations in the auxiliary steam pressure and performs quick response control in response to this pressure fluctuation, it is not suitable for controlling slow operations such as the pre-warming. Most of the time it doesn't perform its function. In particular, this type of regulating valve requires a precise function due to its purpose, so it is quite expensive, and when installed in a pre-warming device, it can be rinsed with just 11 feet due to cost effectiveness. I can't.

Furthermore, since the stop valve controls the cutoff of auxiliary steam supplied from the auxiliary steam generator to the high-pressure turbine, it is sufficient that the auxiliary steam can be accurately stopped even if the operation is slow.

Considering the above points, in prewarming high pressure turbines, etc., if a control function is provided for the opening/closing function of the stop valve, it is possible to achieve the goal without using an expensive control valve with precision operation. can.

Therefore, in order to solve the above problems, the present invention provides a pre-warming device that opens, closes and controls auxiliary steam using a first valve, and achieves the purpose without using an expensive and precisely functioning control valve. There is something to do.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a method in which auxiliary steam at a predetermined set pressure and a predetermined temperature is supplied to the high-pressure turbine': 9, and the high-pressure turbine, etc. is pre-warmed by the auxiliary steam. In the pre-warming device for a steam turbine, an auxiliary steam generator is provided to supply auxiliary steam to the high-pressure turbine, etc., and an auxiliary steam generator is provided between the auxiliary steam generator and the high-pressure turbine. a stop valve for shutting off auxiliary steam supplied from the steam generator to the high-pressure turbines and controlling the auxiliary steam pressure; 1± on tongue
1. A pressure detector that detects the pressure of the supplied auxiliary steam;
An earth force control circuit is provided, which compares the detected pressure signal detected by the pressure detector with a pressure setting signal, and controls the stop valve to open/close by a certain amount when the output signal continues to be applied to the cylinder for a predetermined period of time. It is something.

(Function) Auxiliary steam generated from the auxiliary steam generator is supplied to the high pressure turbine via the 11th valve, and the temperature and pressure of this high pressure turbine are raised. The supply pressure of this auxiliary steam is detected by a pressure detector, and the detected pressure signal is compared with a preset pressure constant signal, and when the output signal continues for a predetermined time, the stop valve is set to a constant value. Open or close control is performed by the amount. Through this control, auxiliary steam at a predetermined temperature and pressure is supplied to the high-pressure turbine, and pre-warming of the high-pressure turbine is performed.

(Example) Hereinafter, an example of the pre-warming device for a steam turbine according to the present invention will be described with reference to FIG. In addition, are the same parts in Figure 1 the same as in Figure 2? ] number and omit the detailed explanation.

A stop valve 30 is provided in the auxiliary steam supply pipe 20 of the auxiliary steam generator 21 to shut off the auxiliary steam supplied from the auxiliary steam generator 21 to the high-pressure turbine 11 and to control the supply pressure thereof. A control circuit 31 is connected to this stop valve 30, and its opening and closing are controlled by the detected pressure signal of the pressure detector 24 and the detected temperature signal of the temperature sensor 26.

This control circuit 31 has a temperature detected by the temperature detector 26 (8
a temperature control section 32 that receives the signal and controls the stop valve 30 to shut off based on the detected temperature signal; and a throttle control circuit 33 that throttles and controls the 11-th valve 30 based on the detected pressure signal of the pressure detector 24.
Also provided is an opening control circuit 34 for controlling opening.

The humidity control unit 32 receives the temperature detection signal of the rotor 15 detected by the temperature detector 26 (11-h), and detects the occupancy (, -).

The signal is compared with a temperature setting signal from a temperature setting device (not shown) built into the temperature control unit 32. The temperature setting signal of this temperature setting device is similar to the temperature control device 27 shown in FIG. Stop valve 30 is closed.

The aperture control circuit 33 and the opening control circuit 34 are similar in terms of electrical circuits, and the nine control circuits 33 and 34 are as follows:
An auxiliary steam pressure signal detected by the pressure detector 24 is received, and the stop valve 30 is controlled to open and close based on this auxiliary steam pressure signal. That is, the throttle control circuit 33 controls the stop valve 30 to close. This throttle control circuit 33 includes an auxiliary steam pressure signal detected by the pressure detector 24 and a pressure setting device 36a.
A comparator 35a is provided for comparing the set pressure signal with the set pressure signal. The pressure setting device 36a is 7,2 (ATG), i.e. 7. O
It is configured to generate a set pressure of +0.2 (ATG) (0.2 (ATG) is a margin value) of 1°, and this signal is constantly sent to the comparator 35a. When the comparator 35a receives the auxiliary steam pressure signal sent from the pressure detector 24, it is compared with the set pressure signal, and when the auxiliary steam pressure signal exceeds the set pressure signal, it outputs an output 1d, for example, a pulse signal (
+1) is output.

When the comparator 35a outputs a pulse signal, this pulse signal is sent to the first timer circuit 38a via the first wipeout circuit 37a. This first timer circuit 38a
is configured to output a pulse signal one minute after receiving the pulse signal from the first wipeout circuit 37a,
This signal is sent to the second wipeout circuit 39a.
and the second timer circuit 40a at the same time. The second timer circuit 40a is configured to output a pulse signal 10 seconds after receiving the pulse signal, and the pulse signal is simultaneously sent to the second wipeout circuit 39a and the first wipeout circuit 37a. It will be done.

Therefore, the output signal of the second wipeout circuit 39a is controlled by the pulse number of the comparator 35a;
, and the stop valve 30 is throttled by a predetermined amount during these 10 seconds.

When the first wipeout circuit 37a receives the pulse signal of the comparator 35a and the pulse signal of the second evening/rpm circuit 40a, the output pulse (signal) is blocked and the pulse (signal) of the comparator 35a is blocked. However, if the pulse signal from the second timer circuit 40a is not received, the output pulse signal is output.The operation of the second wipeout circuit 39a is also the same as the first one. The operation is similar to that of the wipeout circuit 37a of No. 1.However, the output pulse signal of the first timer circuit 38a is used instead of the input signal or the pulse signal of the comparator 35a, and the second wipeout circuit 37a is used as the second output pulse signal. The difference is that the output signal of the timer circuit 40a is used.

Since the opening control circuit 34 is similar to the diaphragm control circuit 33 as described above, parts corresponding to each component of the diaphragm control circuit 33 have b? :) is (,T) and its explanation will be omitted. However, the set pressure signal LL6.8 of the pressure setting device 36b
(ATG), that is, 7.0-〇, 2 (ATG), this set pressure signal is then sent to the comparator 35b, and the auxiliary steam pressure signal sent from the pressure detector 24 is set to this set pressure signal. If the comparison is low, the deviation pulse signal (+
1). Furthermore, when the pulse number 1 of the second wipeout circuit 39b is increased to ILf:1, the stop valve 30 is operated to open as much as possible during the time it receives the pulse number 1.

Pre-warming in the high-pressure turbine 11 configured in this way will be explained.

First, the control valve 14 and the intercept valve 1 are closed, and the control circuit 31 is energized in this state. Due to this energization, the temperature of the rotor 15 is detected by the temperature detector 26, and the temperature signal is sent to the temperature control section 32. Since the temperature of the rotor 15 is lower than the main steam temperature, this temperature detection signal is sent as an output signal from the temperature control section 32 to the stop valve 30, and the stop valve 30 is opened.

Further, when the auxiliary steam pressure is detected by the pressure detector 24, this detected pressure signal is transmitted to the comparator 35a and the comparator 351.
] will be sent to. Since the detected pressure signal at startup etc. is a low pressure signal at the beginning of pre-warming, it is compared with the set pressure signal of the comparator 35b, and the deviation pulse signal of the comparator 35b is sent to the first wipeout circuit 37b.

Since the first wipeout circuit 37b does not receive the pulse signal from the seventh timer circuit 40b, the pulse signal is sent to the first timer circuit 38b. This first
The timer circuit 38b outputs pulse No. 45 after one minute, and the pulse No. 45 is simultaneously sent to the second timer circuit 40b and the second wipeout circuit 39b.

When the second wiper I/circuit 39 Ill receives a pulse signal, the second wiper I/circuit 39b sends a pulse signal to the stop valve 30. At this time tL, the stop valve 30 receives the pulse signal, and while receiving this pulse signal, the stop valve 30 is controlled to open by a certain amount.

After 10 seconds have elapsed, the second timer circuit 40b
- The pulse signal output from the second timer circuit 40b blocks the pulse signal of the second wipeout circuit 39b, and the opening adjustment of the stop valve 30 is stopped.

Therefore, when the detected pressure remains lower than the set pressure for 1 minute, the stop valve 30 receives a pulse signal for only 10 seconds during that 1 minute, and this 10 second pulse signal causes the stop valve 30 to
0 is controlled to open by a certain amount, and auxiliary steam is supplied to the high-pressure turbine 11 according to this opening degree.

Further, the pulse signal of the second timer circuit 40b is simultaneously sent to the first wipeout circuit 37b, and the pulse signal of the first wipeout circuit 37b is blocked. As a result, the first timer circuit 38b is deenergized, and the series of opening operations of the stop valve 30 is completed.

Next, the adjusted auxiliary steam pressure is detected by the pressure detector 24. This detected pressure signal is compared with the set pressure signal of the pressure setter 36b by the comparator 35b, and if it is lower than the set pressure = 16- The above-mentioned operation is further performed to complete the opening operation of the first valve 30.

This operation is repeated once until the set pressure of the auxiliary steam supplied to the high-pressure turbine 11 reaches 6.8 (ATG) or higher.

Also, with this control, the auxiliary steam pressure of the high pressure turbine 11 is 7
．． When the pressure exceeds 2ATG, the detected pressure signal of the pressure detector 24 is sent to the ratio 11 alternator 35a and comparator 35b of the throttle control circuit 33. Since this detected pressure signal is a high pressure signal, it is compared with the set pressure signal of the comparator 35a, and its pulse signal is sent to the first flip-out circuit 37a. In the first wipeout circuit 37a, the pulse 46
The first timer circuit 38a1 and the second timer circuit 40a
, the second wipeout circuit 39a is sequentially operated, and the stop valve 3
It closes to 0 and pulse number 45 is sent. While this pulse signal is being sent, the intermediate valve 30 is closed by a certain amount, and the auxiliary steam supplied from the auxiliary steam generator 2 to the high-pressure turbine 1 is restricted.

The subsequent operation is performed in the same manner as the aperture operation described above.

In this way, the auxiliary steam pressure is maintained at 6.8 to 7.2 (ATG) in the high pressure turbine 11, and the casing, rotor, etc. of the high pressure turbine 11 are warmed to a predetermined pressure and high temperature.

After this warming is done for a while, the casing,
The rotor, etc. becomes close to 158°C. This temperature is detected by the temperature detector 26, and its detection signal is sent to the temperature control section 32. This detection signal causes the 78 degree control section 32 to output an output signal, and the jLl:1 force signal closes the stop valve 3o, cutting off the auxiliary steam supplied to the high pressure turbine 1. This completes the prewarming of the high pressure turbine 11.

When the prewarming is completed, the control valve 14 and the intercept valve 19 are opened, and high pressure steam is supplied from the boiler 1o to the high pressure turbine 1 for normal startup operation.

Therefore, in the descendant pressure turbine 11, even when receiving high-pressure steam, the casing, rotor, etc. are maintained at a high temperature by pre-warming, so that thermal stress does not occur.

In the above embodiment, the timer circuits of the throttle control circuit and the opening control circuit were set to 1 minute and 10 seconds, or the high pressure turbine,
The stop valve, auxiliary steam 1j, amount of supply equipment, performance, purpose, etc. may be changed as desired.

Further, although the first wipeout circuit, first timer circuit, etc. are operated by pulse signals, the same operation can be performed by using analog signals instead of pulse signals.

In the above embodiment, auxiliary steam for pre-warming is supplied to the high pressure turbine 1j1. Although we have explained the supply of main steam, it can also be used for pre-warming of intermediate pressure turbines, etc.

〔Effect of the invention〕

In the steam turbine pre-warming device of the present invention, when auxiliary steam generated from the auxiliary steam supply device is supplied to the high-pressure turbine, this auxiliary steam pressure is detected by a pressure detector, and this detected pressure (No. 1J and preset The set pressure (.) is compared with the output signal, and when the output signal continues for a predetermined period of time, the stop valve is controlled to open and close by a certain amount.As a result, the auxiliary steam for pre-warming, which has a slow pressure oxidation, can be coordinated with the stop valve. can be precisely controlled in a controlled manner.

Furthermore, since the +l valve has an opening/closing function and a control function, there is no need to use a highly viscous and expensive control valve, and the control device can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main parts of a pre-warming device for a steam turbine according to the present invention, and FIG. 2 is a block diagram showing the main parts of a pre-warming device for a steam turbine commonly used in the past. 10... Boiler, ]1... High pressure turbine, 12... Medium pressure/low pressure turbine, 13... Main steam shield, ]4... Control valve, 1
5...Rotor, 16.Low temperature reheating pipe, 17...+lj heater, ]8...High'lA reheating pipe, ]9...Intercept valve, 20...Auxiliary steam supply pipe, 21...・Auxiliary steam generator, 22.30・・Stop valve, 2B・・Adjusting valve, 24・Pressure detector, 25・Pressure control device, 26・Temperature detector, 27・Temperature control device, 28.29・・Drain Valve, 31...Stop valve control device, 32.Temperature detection section, '3
'3...Aperture control circuit, 34.Opening control circuit, 35a. 35 b... Comparator, 36 a, 3 (:>
b −Q constant; (g, 37a, 37b・first wave-out i・circuit, 38a, 38b first timer circuit, 3
C'Ja. 39b...Second wipeout I circuit, 40a. 40b: second timer circuit.

Claims (1)

[Claims] In a steam turbine pre-warming device that supplies auxiliary steam at a predetermined set pressure and predetermined temperature to a high-pressure turbine, etc., and pre-warms the high-pressure turbine, etc., the auxiliary steam is supplied to the high-pressure turbine, etc. An auxiliary steam generator installed between the auxiliary steam generator and a high-pressure turbine, etc., and controls the shutoff of auxiliary steam supplied from the auxiliary steam generator to the high-pressure turbine, etc., and the auxiliary steam pressure. a pressure detector provided between the stop valve and the high-pressure turbine to detect the pressure of auxiliary steam supplied to the high-pressure turbine, and a detected pressure signal and a pressure setting signal detected by the pressure detector. and a pressure control circuit that controls the opening and closing of the stop valve by a certain amount when the output signal continues for a predetermined period of time.