JPH04140405A - Steam turbine power generation equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a steam turbine comprising a boiler, an extraction condensing turbine driven by steam from the boiler, and a generator driven by the turbine. The present invention relates to power generation equipment, particularly steam turbine power generation equipment that can be operated appropriately in areas where the load suddenly increases.

[Conventional technology]

A steam turbine power generation facility is equipped with a boiler, an extraction condensation turbine to which steam from the boiler is supplied via the main steam system, and a generator that converts the power generated by the turbine into electric power and supplies it to the electric load. Are known.

The extraction condensation turbine includes a steam turbine including a high-pressure turbine section and a low-pressure turbine section, and a condenser that condenses exhaust gas from the turbine and maintains it at a predetermined pressure below atmospheric pressure. A high-pressure steam control valve, so-called main steam control valve, is provided at the inlet of the high-pressure turbine section, and a low-pressure steam control valve, so-called bleed air control valve, is provided at the inlet of the low-pressure turbine.

The above-mentioned steam turbine is supplied with steam in an amount corresponding to the turbine load from the boiler via a high-pressure steam control valve, and extracted steam obtained by extracting a part of the exhaust gas from the high-pressure turbine section is supplied to the extraction system. The pressure of 1 atmosphere is controlled by a low-pressure steam control valve to control the extraction pressure to a predetermined pressure, while power is supplied from the generator to the power load.

In addition, a high-pressure bypass system that bypasses the high-pressure turbine section and includes a high-pressure bypass valve that connects the main steam system and the extraction system, and a low-pressure bypass valve that bypasses the low-pressure turbine section and connects the extraction system and the condenser or A low-pressure bypass system is provided that connects the steam accumulator, and when the pressure of steam flowing through the main steam system from the boiler rises above a predetermined pressure due to a sudden load drop, etc., the high-pressure bypass valve opens and excess steam from the boiler is removed. When the pressure of steam in the bleed system rises above a predetermined pressure, a low-pressure bypass valve is opened to release excess steam from the bleed system to the condenser or steam accumulator.

(Problem Ia to be Solved by the Invention) In the above steam turbine power generation equipment, when the power load suddenly decreases, the high pressure steam control valve rapidly reduces its opening and the high pressure turbine section normally cannot tolerate the load change. This rapidly reduces the amount of steam flowing into the high-pressure turbine section. This sudden decrease in the amount of steam causes large temperature changes, increasing thermal stress on the casing and rotor, and shortening the life of the high-pressure turbine section. On the other hand, in the case of a boiler as well, it is necessary to reduce the amount of steam generated in the boiler in response to a sudden load drop, which causes a problem in that the boiler is forced to operate at a rate exceeding the allowable load drop rate.

Furthermore, when the power load increases rapidly, the high pressure steam control valve rapidly increases its opening degree to rapidly increase the amount of steam flowing into the high pressure turbine section at a load change rate that the high pressure turbine section normally cannot tolerate. This rapidly increasing amount of steam causes a problem of large temperature changes (which increases thermal stress on the casing and rotor, shortening the life of the high-pressure turbine section.On the other hand, boilers also experience problems due to the sudden increase in load). Therefore, the boiler is forced to operate at a rate exceeding the allowable load increase rate, and there is a problem in that it is unable to keep up with the increase in turbine load.

An object of the present invention is to provide a steam turbine power generation facility in which a turbine and a boiler can be operated at an appropriate load change rate without shortening the life of a high-pressure turbine section when the power load suddenly decreases.

[Means to solve the problem]

In order to solve the above problems, according to the present invention, a boiler;
A steam turbine consists of a high-pressure turbine section and a low-pressure turbine section to which steam from the boiler is supplied, a condenser that converts the exhaust gas from this turbine into condensate and maintains it at a predetermined pressure below atmospheric pressure, and a steam turbine. The steam turbine includes a high-pressure steam regulating valve that is provided at the inlet of the high-pressure turbine section and controls the pressure of extracted steam extracted from the exhaust section of the high-pressure turbine section and supplied to the extraction system. , a low-pressure steam regulating valve that is provided at the inlet of the low-pressure turbine section, through which exhaust gas other than extracted steam from the high-pressure turbine section flows, and which controls the power that is supplied from the generator to the power load and purchased from the power grid, Furthermore, there is a high-pressure bypass system that bypasses the high-pressure turbine section, connects the main steam system and the extraction system, and has a pressure regulating valve that opens at a predetermined pressure. and the speed of opening and closing respectively!
[It shall be equipped with flexible opening/closing means.

[Operation] In a steam turbine power generation facility consisting of a boiler, an extraction condensation turbine, a generator, etc., the pressure of extracted steam is extracted from a part of the exhaust gas from the high pressure turbine section by a high pressure steam control valve provided in the extraction condensation turbine. On the other hand, the power that is supplied to the power load and purchased from the power grid is controlled so that the amount of power purchased is a predetermined amount using a low-pressure steam control valve that controls the amount of steam flowing through the low-pressure turbine section. Increases and decreases in the power load associated with power control are performed in the low-pressure turbine section. At this time, since the low-pressure turbine section is at a lower temperature than the high-pressure turbine section, the temperature change due to the rapid increase in load is small, and therefore the thermal stress of the low-pressure turbine section is small, and the allowable stress of the material is also high.

Therefore, by appropriately selecting the power load ratio between the high-pressure turbine section and the low-pressure turbine section and controlling the power in the low-pressure turbine section using the low-pressure steam control valve, it is possible to respond favorably to increases and decreases in the power load.

Further, if the steam pressure in the main steam system exceeds a predetermined pressure due to a sudden decrease in negative N in the power load, etc., the pressure regulating valve is opened and excess steam flows to the extraction system. When the steam pressure of the main steam system reaches a predetermined pressure, the pressure regulating valve is closed, and the steam pressure of the main steam system is maintained at the operating pressure.

When the power load suddenly decreases, the pressure rise in the bleed system due to the sudden closing of the low-pressure steam regulator is detected, and the high-pressure steam regulator closes at a speed commensurate with the boiler's allowable load drop rate using the opening/closing means, and the boiler's load drop rate is permissible. Do not exceed the value.

When an increase in the power load is planned, a heat storage operation is performed in advance to increase the amount of steam generated by the boiler. To this extent, the boiler and turbine are operated at an appropriate load increase rate by opening the high-pressure steam control valve and the pressure control valve at an opening speed corresponding to the maximum allowable load increase of the boiler using the opening/closing means.

If the power load suddenly increases after thermal storage operation, the high-pressure steam regulator opens and closes the high-pressure steam regulator at a speed corresponding to the maximum allowable load increase of the high-pressure turbine section. By operating the boiler at a speed where the sum of the amount of air flowing through the boiler corresponds to the maximum allowable load increase,
Prevent the load increase rate of the boiler and high-pressure turbine section from exceeding an allowable value.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a system diagram of a steam turbine power generation facility according to an embodiment of the present invention. In FIG. 1, a steam turbine 1 consists of a high-pressure turbine section 4 and a low-pressure turbine section 5, and high-pressure steam is introduced into the inlet of the high-pressure turbine section 4 from which steam from a boiler 2 flows into the high-pressure turbine section 4 via a main steam system 6. Adjustment valve 7,
A part of the exhaust gas from the high pressure turbine section 4 is extracted into a deaerator 1.
A low pressure steam control valve 9 is provided for supplying the steam to the extraction system 8 connected to the 4° process 11 and for causing the remaining exhaust gas to flow into the low pressure turbine section 5. Here, the high pressure steam control valve 7 is the extraction system 8
The low pressure steam control valve 9 controls the pressure of the extracted steam supplied to the
controls the amount of electricity purchased from the power system 42 by the APC (automatic power controller) to a predetermined amount (hereinafter referred to as APcM).
flj), and the bleed system 8 is provided with a relief valve 27.

The generator 10 is connected to the steam turbine 1, and the steam from the boiler 1 flows to the steam turbine to generate electric power according to the amount of work done, and supplies electric power to a factory load 40 connected to a factory power system 41. . Note that a power system 42 for purchasing power is connected to the factory power system 41.

The condenser 3 condenses the exhaust gas from the low-pressure turbine section 5 and maintains it at a predetermined pressure below atmospheric pressure.

The condenser 3 and boiler 2 are equipped with a deaerator feed water pump 12° and a low pressure feed water heater 13. Deaerator 14. A water supply system 16 including a boiler water supply pump 15 is connected.

The deaerator 14 is connected to the extraction system 8 in order to supply steam for heating and deaerating the feed water flowing into the deaerator 14 . Further, a low-pressure extraction system 18 is connected to the low-pressure feedwater heater I3 to extract and supply steam for heating the feedwater containing condensate from the condenser 3 from the low-pressure turbine section 5. Note that 19 is a drain system that returns drain generated in the low-pressure feed water heater 13 to the condenser 3. Further, 20 is a make-up water system that supplies make-up water to the condenser 3.

The main steam system 6 and the extraction system 8 are provided with a high-pressure bypass system 23 that bypasses the high-pressure turbine section 4 and is equipped with a high-pressure pressure regulating valve 22.
is connected. The high-pressure pressure regulating valve 22 opens when the steam pressure of the main steam system 6 reaches a predetermined pressure, and can be opened and closed at a predetermined speed by a regulating valve opening/closing controller described later.

A low-pressure bypass system 25 that bypasses the low-pressure turbine section 5 and includes a low-pressure pressure regulating valve 24 is connected to the extraction system 8 and the condenser 3 . The low-pressure pressure regulating valve 24 opens when the pressure of the extracted steam in the extraction system 8 reaches a predetermined pressure.

The bleed system 8 is provided with a relief valve 27 that releases steam in the bleed system 8 to the atmosphere when the bleed pressure reaches a predetermined abnormally high pressure.

Here, the relief valve 27 is opened or controlled at a predetermined pressure of the extracted steam in the extraction system 8. Low pressure pressure regulating valve 24. High pressure steam control valve7. The set pressure of the high-pressure pressure regulating valve 22 is gradually decreased in the above order.

The control unit 30 detects the rotation speed detected by the rotation speed detector 31.

Purchased power detected by power detector 32, pressure detector 33
The steam pressure of the main steam system 6 detected by the pressure detector 34 and the bleed steam pressure of the bleed system 8 detected by the pressure detector 34 are input, and these input signals cause the high pressure steam control valve 7 and the low pressure steam control valve 9 to be input.
A speed governor that controls speed.

A load setting device that sets the power load, a bleed pressure controller that controls the high-pressure steam regulator to control the bleed pressure, and a bleed pressure controller that controls the bleed pressure to supply electricity to the power load and purchase a predetermined amount of electricity from the power grid.
APC that controls the low pressure steam control valve for PCIIll
Adjustment valve opening/closing controller that controls the valve opening/closing speed of the high-pressure steam adjustment valve and high-pressure pressure adjustment valve when the load suddenly decreases.
g Consists of valve opening/closing controller, etc.

The operation of the steam turbine power generation equipment with such a configuration will be explained. Steady operation of this power generation equipment is performed as follows.

When steam is supplied from the boiler 2 to the steam turbine 1, it flows into the high-pressure turbine section 4 through the high-pressure steam control valve 7 and does work, and a part of the exhaust gas is taken out and supplied to the extraction system 8. The remaining exhaust gas passes through the low-pressure steam control valve 9 and flows to the low-pressure turbine section 5 to perform work, and the exhaust gas is led to the condenser 3 and becomes condensed water, where it is maintained at a predetermined pressure below atmospheric pressure. At this time, the non-condensable gas in the condenser 3 is discharged to the outside by an ejector (not shown).

The generator IO generates electric power corresponding to the amount of work performed by steam flowing through the high-pressure and low-pressure turbine sections 4 and 5, and supplies it to a factory load 40 as an electric power load. At this time, a predetermined amount of power is purchased from the power system 42.

The feed water, which is a mixture of condensate and make-up water in the condenser 3, is pressurized by the deaerator feed water pump 12 and passes through the low pressure bleed water system 18 at the low pressure feed water heater 13. After being heated and heated by the extracted steam, the water is sent to the deaerator 14. The supplied water is heated and degassed in the deaerator 14 by extraction steam passing through the extraction system 8.
The pressure is increased by the boiler feed water pump 15 and the water is supplied to the boiler 2 . The feed water supplied to the boiler 2 is turned into steam in the boiler 2, and is sent to the steam turbine 1 as described above.

Note that the condenser 3 is supplied with make-up water via the make-up water system 20 in an amount corresponding to the amount of steam supplied to the outside via the extraction system 8 .

By the way, when the steam pressure in the bleed system 8 changes due to a change in the amount of steam consumed by the process 11 or the deaerator 14, the bleed pressure controller in the control unit 30 to which the pressure detected by the pressure detector 34 is input controls the high-pressure steam. The regulating valve 7 is controlled and the bleed pressure is maintained at a predetermined pressure.

Further, when the power load of the factory load 40 changes, the purchased power detected by the power detector 32 is input to the control unit 3.
The low-pressure steam control valve 9 is controlled by the APC III controller that performs APCIJ control within 0, and the purchased power is controlled to a predetermined amount, so that the required power is supplied from the generator 10 to the power load.

In the above case, the main steam system 6 is operated such that the steam pressure in the main steam system 6 reaches the operating pressure due to combustion in the boiler 3. At this time, the main steam system 6
When the steam pressure exceeds a predetermined pressure, the high-pressure pressure regulating valve 22 is opened, and excess steam is released to the extraction system 8 via the high-pressure bypass system 23.

Next, a case where the power load suddenly decreases will be explained.

In this case, the low-pressure steam control valve 9 is controlled and suddenly closed by the APC III device of the control unit 30 to which the purchased power detected by the power detector 32 is input, and the APC@ be controlled. At this time, the bleed pressure in the bleed system 8 increases due to the sudden closing of the low pressure steam control valve 9. This pressure rise is detected by the pressure detector 34, and the high-pressure steam regulator 7 is closed at a valve closing speed corresponding to the maximum allowable descending speed of the boiler 2 by the regulator valve opening/closing controller of the control unit 30 to which this detected pressure is input. Then, steam is supplied to the turbine to cope with the sudden load reduction.

At this time, the bleed pressure in the bleed system 8 further increases, and if it exceeds a predetermined pressure, the pressure detected by the pressure detector 34 opens the low pressure regulating valve 24, and excess steam is transferred to the low pressure bypass system 25.
The air is released to the condenser 3 via the air bleed system 8, and the bleed pressure of the bleed air system 8 is controlled. When the load stops decreasing and reaches a constant load, the low-pressure steam control valve 9 stops closing, the low-pressure pressure control valve 24 closes, and the bleed pressure is controlled.

Next, when a load increase is scheduled, the amount of steam generated by the boiler is increased in advance (thermal storage operation will be explained. The valve is opened at a valve opening speed corresponding to the maximum allowable load increase in step 2. At this time, the amount of steam supplied to the turbine increases, and the APC @ control operates to close the low pressure steam control valve 9 in the closing direction, and the extraction system The bleed pressure at 8 increases. If the bleed pressure exceeds a predetermined pressure due to this pressure increase, the low pressure pressure regulating valve 24 opens to release excess steam to the condenser 3, and the opening degree of the low pressure steam regulating valve 9 increases. When the predetermined value is reached, the high pressure steam control valve 7 maintains its opening degree.After that, the control unit 3
The high-pressure pressure regulating valve 22 is opened at a valve opening speed corresponding to the maximum allowable load increase of the boiler by the regulating valve opening/closing controller of No. 0, and the boiler is operated until a predetermined boiler steam amount is reached, and this state is maintained.

By causing the boiler to generate an amount of steam corresponding to the amount of load that is expected to increase in this manner, the turbine load can be rapidly increased when the load increases.

Next, a case where the power load increases rapidly will be explained. In this case, it is assumed that the heat storage operation described above has been completed. In this case, the high-pressure steam control valve 7 is opened at a speed corresponding to the maximum permissible change increase in the high-pressure turbine section 4 by the control section 30's control valve opening/closing controller. At this time, the high-pressure pressure regulating valve 22 is controlled by the regulating valve opening/closing controller to control the high-pressure steam control valve 7 and the high-pressure pressure regulating valve 2.
The boiler operates at a speed where the sum of the steam flow rates flowing through the boiler and the boiler corresponds to the maximum allowable load increase.

In this way, the power load rapidly increases and becomes the main load, and when the amount of steam generated by the boiler 3 reaches the amount of steam corresponding to the power load, the high-pressure pressure regulating valve 22 is closed and a steady operating state is established.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the oil pressure is controlled by the high pressure steam control valve of the extraction condensation turbine,
Power control by APC control is performed by a low-pressure steam control valve, and the high-pressure turbine section is bypassed to connect to the main steam system.
By making the high-pressure pressure regulating valve of the high-pressure bypass system connected to the extraction system and the high-pressure steam regulating valve open and close corresponding to the load change rate of the boiler and high-pressure turbine section, APC @ control of electric power can be performed at low temperatures. This is done by changing the amount of work of the steam in the low-pressure turbine section, so even if the power load suddenly changes, thermal stress due to temperature changes will not be large (and the allowable stress of the material can be large), thus extending the life of the turbine. can do.

In addition, when the power load suddenly decreases, the high-pressure steam control valve closes at a speed corresponding to the allowable load drop rate of the boiler, and during thermal storage operation, the high-pressure steam control valve and high-pressure pressure control valve close at a speed corresponding to the allowable load increase of the boiler. When the load suddenly increases, the high-pressure steam regulating valve is opened at a speed corresponding to the permissible load change of the high-pressure turbine section of the turbine. The boiler and turbine operate at a speed corresponding to the boiler's maximum allowable load increase, so the boiler and turbine can operate at an appropriate load change rate in any of the above cases, such as sudden load reduction, heat storage operation, or sudden load increase. This has the effect of eliminating large life consumption of boilers and turbines.

[Brief explanation of drawings]

FIG. 1 is a system diagram of a steam turbine power generation facility according to an embodiment of the present invention. 1: Steam turbine, 2: Boiler, 3: Condenser, 4: High pressure turbine section, 5: Low pressure turbine section, 6: Main steam system, 7:
High pressure steam control valve, 8: Extraction system, 9: Low pressure steam control valve, 1
0: Generator, 22: High pressure pressure regulation valve, 23: High pressure bypass system, 24: Low pressure pressure regulation valve, 25: Low pressure bypass system,
30: Control unit, 42: Power system, /-

Claims (1)

[Claims] 1) A steam turbine consisting of a boiler, a high-pressure turbine section and a low-pressure turbine section to which steam from the boiler is supplied, and a condenser that converts the exhaust gas from the turbine into condensate and maintains it at a predetermined pressure below atmospheric pressure. and a generator connected to a steam turbine, which is installed at the inlet of a high-pressure turbine section and controls the pressure of extracted steam extracted from the exhaust section of the high-pressure turbine section and supplied to the extraction system. A high-pressure steam control valve and a low-pressure steam control valve installed at the inlet of the low-pressure turbine section that allows exhaust gas other than extracted steam from the high-pressure turbine section to flow, and controls the power that is supplied from the generator to the power load and purchased from the power grid. A high-pressure bypass system has a pressure regulating valve that bypasses the high-pressure turbine section, connects the main steam system and the extraction system, and opens at a predetermined pressure. A steam turbine power generation facility characterized by comprising speed-adjustable opening/closing means for opening and closing a high-pressure steam control valve and a high-pressure steam control valve.