JPH0333887B2 - - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an improved steam storage device in a steam storage power generation facility.

[Technical background of the invention and its problems] Steam turbine plants having a steam storage power generation system consisting of a steam bleed valve, a steam storage tank, and a peak turbine are being put into practical use. originally,
The development of electric power energy has been promoted mainly by highly rigid power sources such as nuclear power, LNG-fired power, and coal-fired power in order to meet expected future power demand. On the other hand, the growth in maximum electric power is expected to continue increasing in the future, and the increasing proportion of nuclear power and coal-fired power generation, which have frequent startups and stops and are difficult to follow due to their fine-grained load, will require some countermeasures. It is required. As part of this effort, the development of pumped storage power generation is being promoted, but in thermal power plants, coal Oil for firepower. The so-called steam storage power generation system, which stores steam in the form of hot water in a pressure vessel at night in the form of hot water and releases it to generate electricity in order to handle the maximum amount of electricity during the day, has been revised and developed to operate on par with thermal power. Planning has begun.

In the power generation operation method of a steam turbine plant equipped with this steam storage power generation system, there is a steam storage operation mode at night and a peak generation operation in which steam is released from the steam storage tank to drive the peak generation turbine during peak power demand during the day. It can be classified into modes. However, in this peak power generation operation mode, the steam storage tank uses the principle that steam is blown into saturated water from a steam source, and by opening it when necessary, the water self-evaporates by the pressure difference. Therefore, the tank internal pressure must be higher than the peak turbine inlet vapor pressure by a certain value. From the viewpoint of the power generation efficiency of the peak turbine, it is desirable to increase the main steam pressure of the peak turbine and to increase the pressure within the storage tank to some extent. Furthermore, by satisfying this condition, the storage energy density becomes high, the capacity of the steam storage tank can be reduced, and effects on equipment and construction costs can be exhibited.

However, the reheat steam line pressure, which is the source of steam supplied to the steam storage tank, depends on the steam turbine load in approximately proportion to the steam turbine load. For example, the reheat line steam pressure P ₁ can be increased to P ₂ . When trying to increase the internal pressure of the storage tank, the steam turbine load must also be increased from L ₁ (for example, 30% load) to L ₂ (for example, 60% load) to match the increase. This means that the nighttime output in storage operation mode is kept below the boiler's minimum load operation (for example, around 25%),
This deviates from the original goal of operating intermediate-load thermal power on par with oil-thermal power. The solution is to reduce the boiler load to the minimum load that can be maintained stably, and then throttle the intercept valve installed at the inlet of the intermediate pressure turbine to increase the reheat steam line pressure to obtain the desired extraction pressure, that is, the pressure in the storage tank. However, no specific operating method or control method has been found yet.

[Object of the Invention] The object of the present invention is to provide a steam storage power generation facility that can store steam in a steam storage tank with high storage energy density and that can operate steam storage power generation efficiently and stably. To provide steam storage equipment.

[Summary of the invention] The steam storage device of the steam storage power generation equipment of the present invention includes:
In a steam turbine plant having a steam storage power generation system, an intercept valve installed in the reheat steam line of the steam turbine, an extraction adjustment valve installed in the system that supplies the extraction air of the reheat steam to the steam storage tank, and a control valve installed during storage operation. A control device having a control system that provides an opening throttle signal to the intercept valve, and a control system that provides an opening signal that corresponds to the differential pressure between the extraction regulating valve, the extracted steam pressure, and the internal pressure of the storage tank. It is characterized by:

[Embodiment of the Invention] The present invention will be described below with reference to an embodiment shown in FIGS. 1 and 2. In FIG. 1, a steam turbine power generation plant employing a steam storage power generation system includes a steam turbine power generation system 4 consisting of a boiler 1, a high pressure turbine 2a, an intermediate pressure turbine 2b, a low pressure turbine 2c, and a generator 3. It is equipped with a steam storage power generation system 8 consisting of a steam storage tank 5 that stores a part of the steam of the power generation system 4, a peak turbine 6 that is driven by the supply of steam from the steam storage tank 5, and a peak generator 7 that is directly connected to this. It consists of the following equipment.

That is, in the steam turbine power generation system 4, the main steam of the boiler 1 is supplied to the high-pressure turbine 2a through the piping 9, the main stop valve 10 and the steam control valve 11, and the steam worked there is sent to the piping 12.
After being reheated in the reheater 13 of the boiler 1, it is passed through the piping 14 to the steam stop valve 15 and the steam control valve 1.
The steam that has worked there is led to the low pressure turbine 2c through piping 17, and the steam that has finished working is led to the condenser 18, where it becomes condensed water and is sent from piping 19 to the boiler 1. Return to In this steam turbine power generation system 4, the generator 3 is driven by the turbines 2a, 2b, and 2c to generate electric power.

In the steam storage power generation system 8, reheated steam from the reheated steam piping 14 of the steam turbine power generation system 4 is extracted by an extraction piping 20 having an extraction valve 20a, and is extracted by an extraction valve 20b, a heat storage device 21, and an extraction valve 20c. The vapor is stored in the vapor storage tank 5 through the vapor storage tank 5. The steam in this steam storage tank 5 passes through the steam valve 22a and the heat storage device 21 as necessary.
It is led from the steam valve 22b to the peak turbine 6 through the piping 23, where it works, becomes condensate in the condenser 24, and is led from the condensate storage tank 27 to the condenser 18 via the piping 28 by pumps 25 and 26. It will be destroyed. This steam storage power generation system 8 generates electric power by driving a peak turbine 6 using steam in a steam storage tank 5, and operating a peak generator 7 directly connected thereto.

Therefore, in the present invention, in a steam turbine plant consisting of a steam turbine power generation system 4 and a steam storage power generation system 8, a control device that controls the opening degree of the steam control valve 16 of the intermediate pressure turbine 2b and the pressure of the reheat steam line is provided. 29, and the output signals S ₁ and S ₂ are used to adjust the openings of the steam control valve 16 and the bleed valve 20b.

The control device 29 includes a control system 30 for the intercept valve 16 of the intermediate pressure turbine 2b and a control system 31 for the bleed valve 20b of the steam storage tank 5, as shown in FIG. The intercept valve control system 30 is a system in which a rotational speed error signal 32 and an intercept valve fully open bias signal 33a are processed by a calculator 34a, and a load setting signal 35 and an intercept valve fully open bias signal 33b are processed by a calculator 34b.
Calculate this and intercept it with valve opening transmitter 3.
The normal operation loop 37 and load setting signal 35 that are input to the calculator 34a through 6 are directly input to the calculator 34a.
and an emergency operation loop 38 that inputs to a. Then, the normal operation loop 37 and the emergency operation loop 38 are switched by the changeover switch 39, and the arithmetic unit 3
4a and produces a signal S ₁ for the intercept valve 16. As shown in FIG. 3a, this changeover switch 39 is set to normal operation mode a to c by an AND circuit of a storage operation mode selection signal 40 and a condition in which an emergency signal 41 at the time of turbine trip or load interruption does not exist. or emergency operation mode a-b
Switch to .

In addition, the control system 31 for the bleed valve 20b processes the signal P ₁ of the internal pressure oscillator 42 of the storage tank 5 and the pressure transmitter 43 of the reheat steam line of the boiler 1 with a calculator 34c, and uses the output ΔP as the bleed air The signal is input to the stop valve opening transmitter 44, and the output thereof and the bleed valve fully closed bias 45 are selectively switched by a changeover switch 46 to generate a signal _S2 for controlling the bleed valve 20b.

Next, a steam storage device for a steam storage power generation facility according to the present invention will be explained. In the control device shown in FIG. 2, during normal operation other than storage operation mode, the intercept valve 16 receives a rotational speed error signal 32 from the speed detector, a full open bias signal 33a that maintains the valve opening fully open except in an emergency, and It is fully opened by a signal from the load setting device 35. This intercept valve 16 is originally intended to block steam from flowing into the intermediate pressure turbine 2b and beyond in an emergency, and its characteristics are shown on the horizontal axis in FIG. 4 by the load setting signal L.
and the opening degree 16A of the intercept valve 16 is shown on the vertical axis.
As shown by the solid line 16A, the entire load setting device is fully opened. On the other hand, since the storage operation mode selection signal 40 in FIG. 3b is not output to the bleed valve 20b, the changeover switch 46 forms the circuit c-b and is fully closed upon receiving the fully closed bias signal 45. Become.

Now, in a typical storage operation mode, as shown in Fig. 5, the time Ta-Tb is the storage operation selection period, and the time
Tb−Tc is the bleed storage operation period and time Tc−T _D
can be broadly divided into the storage operation end period. When the storage operation mode is selected at time Ta, the selector switch 39 in FIG. 2 switches to circuit a-c as shown in the switching conditions in FIG. 35
The opening is controlled as shown in FIG. 5 by the output signal of the intercept valve opening transmitter 36, which receives the setting signal from the opening 16A in FIG. On the other hand, at the same time as the start of the storage operation mode, the boiler load 60 and the main turbine load 61 are lowered to the storage operation state as shown in FIG. In response to the signal of the storage operation mode 40 in Fig. 3b, the circuit a
-b is formed and the extraction storage operation is started, so the boiler load 60 and the turbine load 61 will differ by that amount.

On the other hand, the reheat line steam pressure P ₀ originally changes as shown by the solid line in FIG. 4, the opening degree of the intercept valve 16 is further narrowed down, and the reheat steam line pressure P ₀ changes as shown by the broken line in FIG. 6. This means that the reheat steam line pressure P ₀ can be increased while the turbine load is lowered as described above, and the decrease in the reheat steam line pressure P ₀ shown in FIG. The internal pressure P 1 of the storage tank 5 can be made even higher than the internal pressure P ₁ in the uncontrolled state. In addition, the bleed valve 20b
The valve opening degree transmitter 44 detects the pressure P ₀ of the reheat steam line and the internal pressure P ₁ of the storage tank 5 when it is planned to maintain the amount of extracted air constantly constant in the storage operation mode.
The input signal is the differential pressure ΔP between the bleed valve 20b and the bleed valve 20b. . The internal pressure _P1 of the storage tank 5 increases as the amount of stored steam increases, and if the opening degree of the extraction valve 20b is kept constant, the amount of extracted steam will also gradually decrease.

In the extraction storage operation state between time Tb and Tc, as shown in FIG. 5, the boiler load 60, the turbine load 61, and the intercept valve opening 16A are stabilized. However, the internal pressure _P1 of the storage tank 5 increases with the change in the amount of steam stored,
The amount of bleed air is kept constant by the bleed air opening transmitter 44,
Therefore, the reheat line steam pressure P ₀ can also be maintained constant, and stable operation can be performed.

At the end of storage operation between time Tc and TD,
The boiler load 60 and the turbine load 61 are increased again, but as these increases, the opening degree 16A of the intercept valve 16 and the reheat line steam pressure P ₀ are also returned to the load equivalent during normal operation. The opening degree of the bleed valve 20b changes to 20 as the internal pressure _P1 of the storage tank 5 increases.
l is also increased as shown in Figure 5, but during storage operation
In TD, it will be fully closed automatically.

In this way, in the steam storage device according to the present invention, by attaching the control device 29,
It is now possible to control the reheat turbine pressure, that is, the extracted steam pressure P ₀ in the storage operation mode, using the intercept valve 16 without significantly modifying the current main turbine side control device. Steam can also be stably supplied and stored by the bleed valve 20b.

Next, FIG. 7 shows another embodiment of the control system 30 for the intercept valve 16 in the control device 29 according to the present invention. In this embodiment, the reheat line pressure setting device 73 is a setting device that inputs a signal from the load setting signal 35 to ensure a desired reheat line pressure _P0 , and uses this output signal and the reheat line pressure setting device 73 as input. The calculation signal with the output signal of the line pressure transmitter 43 is the proportional calculator or the proportional + integral calculator 7.
0 to the low value priority circuit 71 of the control circuit of the intercept valve 16. Even when the control system shown in FIG. 7 is used, it is possible to reliably maintain the reheat line pressure P ₀ as in the operating mode shown in FIG. 5.

Furthermore, in the control system shown in FIG. 8, the reheat line pressure setting device 74 is set manually or by other factors (for example, the internal pressure of the storage tank or the amount of extracted air), and the turbine load is kept constant. This is effective when changing the reheat line pressure during storage operation mode.

Although the present invention has been described under the condition that the storage tank 5 is single and the amount of bleed air is constant during the storage operation mode, there is a plurality of storage tanks 5, and the amount of bleed air is constant. It is also useful in plants where the quantity is changed during storage operation mode.

[Effects of the Invention] As described above, in the steam storage device of the steam storage power generation equipment according to the present invention, by narrowing the opening degree of the intercept valve provided at the inlet of the intermediate pressure turbine during the storage operation mode at night, the reheat steam line The pressure can be increased from the value during boiler minimum load operation to the value during storage operation, and the stored energy can be stored in a high density state. By controlling the valve opening so that the amount of steam is constant, the turbine output is also constant, the amount of steam generated by the boiler is also constant, and the entire plant can be operated in a stable state.

[Brief explanation of drawings]

Figure 1 is a plant configuration diagram for implementing a steam storage device for a steam storage power generation facility according to the present invention;
The figure is a control block diagram of the intercept valve and bleed valve used in the steam storage device of the present invention, Fig. 3a
and b is an explanatory diagram of the operation of the changeover switch used in the control block diagram, FIG. 4 is an opening characteristic diagram of the intercept valve, FIG. 5 is an operation mode diagram of the steam storage power generation equipment of the present invention, and FIG. A characteristic diagram showing the relationship between thermal steam line pressure and turbine load, and FIGS. 7 and 8 are block diagrams showing other embodiments of the intercept valve control system used in the present invention. 1...Boiler, 2a, 2b, 2c...High pressure, medium pressure,
Low pressure turbine, 3... Generator, 4... Steam turbine plant, 5... Steam storage tank, 6... Peak turbine, 7... Peak generator, 8... Steam storage power plant, 16... Intercept valve, 20... Reheat steam line, 20a, 20b, 20c...Bleed valve, 29...
Control device, 30...Intercept valve control system, 31
... Bleed valve control system, 32 ... Rotation speed error signal, 33
a, 33b... Intercept valve full open bias signal, 34a, 34b, 34c... Arithmetic unit, 35... Load setting signal, 36... Intercept valve opening oscillator, 39... Normal operation-emergency operation changeover switch, 4
0...Storage operation mode selection, 41...Emergency signal, 42
... Storage tank internal pressure oscillator, 43... Reheat steam line pressure oscillator, 44... Bleed valve opening degree oscillator, 45... Bleed valve fully closed bias, 46... Changeover switch.

Claims (1)

[Claims] 1 In a steam turbine plant having a steam storage power generation system, an intercept valve installed in the reheat steam line of the steam turbine, an extraction adjustment valve installed in the system that supplies the extraction air of the reheat steam to the steam storage tank, and a storage operation a control device having a control system that gives an opening throttle signal to the intercept valve at the time; and a control system that gives the bleed air regulating valve an opening signal that corresponds to a pressure difference between the extracted steam pressure and the pressure inside the storage tank. A steam storage device for a steam storage power generation facility, characterized in that: