JPH02157405A - Steam turbine plant - Google Patents

Abstract

PURPOSE:To recover a part of the energy, which does not contribute to power generation, as the power by providing a water wheel in parallel with a boiler water supplying line between a feed water pump and a boiler. CONSTITUTION:A water wheel 12 is rotated by high pressure boiler feed water, whose pressure was raised by a boiler feed pump 10, so that the power is generated by a generator 13. The water wheel 12 is provided with variable pitch blades, and the feed water is sent to a boiler 1 with suitable pressure. When the plant enters an ordinary operation, a valve 14 is fully closed and a valve 15 is fully opened, thereby bypassing the water wheel 12. Thus, it becomes possible that, when the plant is started, the water wheel 12 is rotated by the feed water sent from the boiler feed pump 10 and that the electric output obtained by the energy of the water wheel 12 makes up for the power necessary for auxiliary machinery of the plant.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a steam turbine plant having a turbine-driven water supply pump, and in particular incorporates a water turbine generator in the water supply line to provide effective The present invention relates to a steam turbine plant capable of recovering power.

(Prior Art) Conventionally, when starting up a turbine plant, the steam generated by the boiler is wasted into a condenser from boiler ignition to turbine ventilation (injection of generated steam from the boiler into the turbine). This is because if ventilation is performed while the temperature of the steam generated by the boiler is lower than the temperature of the turbine rotor, thermal stress will occur in the turbine rotor, causing cracks in the rotor. Therefore, by circulating feed water through the boiler, it is necessary to wait until the steam generated by the boiler reaches a temperature suitable for turbine ventilation.

This situation will be explained with reference to FIG. 2, which shows a conventional plant configuration. Steam generated in the boiler 1 does not enter the high pressure turbine 2 but is guided to the reheater 4 through the high pressure bypass valve 3. The steam leaving the reheater 4 is sent to the intermediate pressure turbine 5.
．． It does not enter the low pressure turbine 6 either, but enters the condenser 8 through the low pressure bypass valve 7. At this time, a part of the steam generated by the boiler 1 is transferred to the boiler feedwater pump drive turbine 9 (hereinafter BP).
PT) and boiler feed water pump 10 (hereinafter referred to as BF).
(referred to as P), the water supplied from the condenser 8 is boosted in pressure and sent to the boiler 1 again through the high-pressure heater 11. After repeating such circulation until the temperature of the steam generated by the boiler 1 reaches a temperature suitable for turbine ventilation, ventilation is performed.

(Problems to be Solved by the Invention) As described above, in the conventional technology, from boiler ignition to turbine ventilation, the energy of the steam generated in the boiler 1 is BF
All of the capacitors except for those used for PIO were sent to capacitor 8.

The object of the present invention is to provide a steam turbine that recovers a portion of such energy that does not contribute to the generation of power as power, thereby reducing the external power supply required to operate plant auxiliary equipment at the time of plant startup. The goal is to provide plants.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a steam turbine plant having a feed water pump driven by a turbine in a path from a condenser to a boiler, in which a feed water line runs from the feed water pump to the boiler. It is characterized by having a water wheel or a pump water wheel installed in parallel with the water wheel.

(Function) If a water wheel is installed in parallel with the water supply line, the water supplied from the water pump when the plant is started will rotate the water wheel.
The power can be used to generate electricity and provide electrical output.

This electrical output is used to cover the power required by plant auxiliary equipment.

(Example) An example of the present invention will be described below with reference to FIG. In the configuration shown in FIG. 1, the same components as those shown in FIG. 2 are designated by the same reference numerals, and the explanation thereof will be omitted.

In the present invention, the water turbine 12 is rotated by high-pressure boiler water supplied by the RFPIO, and the generator 13 generates electricity. The water turbine 12 has variable blades, and feed water is sent to the boiler 1 at an appropriate pressure. When the plant enters normal operation, the valves 14, 1.5 are operated to bypass the water turbine 12. That is, the valve 14 is fully closed, and the valve 15 is closed.
fully open.

The operation of the present invention is illustrated in a standard 600 MW steam turbine plant. From boiler ignition to turbine ventilation, approximately 500 ton/h of feed water is circulated through boiler 1, and the amount of steam required for BFPIO at this time is several tens of thousands of tons. Oton/h and BFP at this time
The discharge pressure of IO is about 100 atg.

Steam sent to BFPIO is sent to boiler 1 immediately after boiler ignition.
Since the temperature of the generated steam is low, it is supplied from another steam source, and after the temperature of the generated steam of the boiler 1 rises to a temperature suitable for venting the BFPT9, this steam is sent to the BFPT9. On the other hand, at rated load, the pressure of the steam sent to BFPIO is 9ata, the temperature is 330℃, and the flow rate is 1
00 ton/h.

The discharge pressure of RFPIO at this time is about 300 atg. Conventionally, at startup, B F' P T 9 and several 10
BFP of about 100 atg by sending ton/h of steam
However, in the present invention, 100 t/h of steam is discharged to the condenser 8.
ton/h is sent to BFPIO to generate a discharge pressure of 300 atg. However, since the pressure required for the boiler 1 is 100 atg, the water turbine 12 can recover energy equivalent to 200 atg. These situations will be explained using FIG. 2. Figure 2 shows the amount of water supplied over time.
Shows the change in the amount of extracted air to the main steam amount, BF P T9 1. At the time of startup of the current steam turbine plant, the amount of water supplied to the boiler 1 is the line segment OG I K, and the amount of main steam entering the main turbine is It is represented by line segment BJ. Water supply time 0
From A to A, an electric water supply pump (not shown) is used, and in one hour A, the steam from the boiler 1 can be vented to the BFPIO, and the water supply is switched to the BFPIO. Time B
At this point, the steam from the boiler 1 can also be vented to the main turbine, and the high pressure turbine 2 is vented. B F
The amount of oil to PT9 is expressed by the difference between line segment ACDIK and line segment OBJ, but for stable combustion in boiler 1, the water supply flow rate from time A to L is constant at about 30% of normal operation. The steam in the portion indicated by the diagram 0ACDIG, which is supplied with water, will be discarded to the condenser 8 through the high-pressure and low-pressure bypass valves 3.7.

In the present invention, the amount of bleed air to BFPIO is calculated by the line segment AE
It is expressed as the difference between FHI K and line segment OBJ, and the figure CDI
The steam in the area indicated by HFE (shaded area) is conventional BF.
It is added to the steam being supplied to PT9 and enters RFPIO, which gives the feed water a discharge pressure higher than necessary.

This excess pressure is recovered as power by a water wheel 12 placed in the water supply line.

When we actually calculate the power generated by a water turbine generator, we get the following.

P=ρ・gu・H−Q・ηH・η. / 1000 generated power (Ksu) Water density = tooOkg/I Gravitational acceleration = 98m/s2 Effective head'': 200at
9 Generator efficiency = 0.95 P = 1000 x 9.8 x 2(X)OX O
,14X O,9X O,95/ 1000 valve 2300
Kw The highest head of existing water turbines is 600 m or more, and the above output can be obtained by connecting water turbines with such high heads in series.

In addition, the actual time that RFPIO can be operated with the steam generated in boiler 1 is 12 hours from ignition to ventilation with a cold start.
In the case of 0 minutes, it is approximately 60 minutes, and the amount of power obtained in this case is 2300 Ksh.

The auxiliary power required to operate plant auxiliary equipment in an oil-fired steam turbine plant is approximately 3% of the rated output, and in a 600 MW plant it is approximately 18,000 MW.
It becomes KV. The output obtained by the water turbine 12 is more than 10% of the required auxiliary power, and the external power supply can be reduced by this amount at the time of startup.

FIG. 3 shows another embodiment of the invention. In this embodiment, two tanks of different heights are installed, and the water turbine generator used at startup is used as a water pump to pump water using surplus electricity late at night. During normal operation, the valve 14 is closed and the feed water pressurized by the RFPIO is sent directly to the boiler 1. When generating power using the start-up water tank] 2, fully close the valve 14 and close the valve 15.1.
6 is fully closed and high pressure water is sent to the water wheel 12. Late at night, if there is surplus power, perform normal operation and close valve 16.
17 and fully open valves 18 and 19 to pump water from the water storage tank 20 to the pumping tank 21. At this time, the water turbine 12 works as a pump and the generator 13 works as a motor.

On the other hand, if there is a power outage in the entire power plant due to a system accident, etc., the valves 16, 18, and 19 are fully opened, the valve 17 is fully opened, the water in the pumping tank 21 is drained, and the water turbine 12 can generate electricity.

In a steam turbine plant, there are tanks of different heights, the condenser 8 and the dealator water storage tank.
If these can be used as water storage tanks and water pumping tanks, there is no need to install new tanks.

〔Effect of the invention〕

As described above, according to the present invention, the steam generated by the boiler, which was wasted at the time of plant startup, can be recovered as power, and the electric power necessary to operate the plant auxiliary equipment can be covered by the electric power recovered at that time. This has the excellent effect of significantly saving energy.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a steam turbine plant according to the present invention;
Figure 2 shows the amount of water supplied and main steam amount versus time. FIG. 3 is a state diagram showing changes in oil amount, FIG. 3 is a configuration diagram showing another embodiment of the present invention, and FIG. 4 is a system diagram showing a conventional steam turbine plant. 3... High pressure bypass valve 7... Low pressure bypass valve 9... Boiler feed water pump drive turbine 10... Boiler feed water pump 12... Water turbine 13... Generator 14, 15.16.17.18 .19...Valve 20
... Water storage tank 21 ... Pumping tank agent Patent attorney Norihiro Ken Yudo Daishimaru Ken

Claims (1)

[Claims] A steam turbine plant having a water supply pump driven by a turbine in a path from a condenser to a boiler, characterized in that a water turbine or a pump turbine is provided in parallel with a water supply line extending from the water supply pump to the boiler. .