JPH0544405A - Steam turbine plant - Google Patents

Abstract

PURPOSE:To reduce the water storage capacity of a deaerator by providing a pipe line that feeds the drain of steam after it heats condensed water in a feed water heater to a water storage tank inside the deaerator in a stem turbine plant that feeds condensed water to a steam generating means by means of a feed water pump. CONSTITUTION:Condensed water fed from a condenser 4 is further raised in its temperature by a feed water heater 7 after its temperature is raised by a feed water heater 6 and flows into a deaerator 8, hence the temperature of drain discharged after it heats condensed water in the feed water heater 6 is lower that the temperature of the condensed water stored in the deaerator 8. This drain if fed by a duct line 17, to a converging device 20 in a water storage tank 19 inside the deaerator 8 and injected forth into the condensed water from the converging device 20, thereby the condensed water in the water storage tank 19 and the drain of low temperature are put in mutual confluence and mixed, and condensed water whose temperature is lower than that of the condensed water inside the deaeraor 8 can be supplied from the water storage tank 19 to a feed water pump 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam turbine plant applied to thermal power plants, nuclear power plants and the like.

[0002]

2. Description of the Related Art FIG. 3 is an explanatory diagram of a conventional steam turbine used in a nuclear power plant or the like. In the figure, the steam supplied from the steam generator 1 to the turbine 3 is condensed in the condenser 4 after having worked in the turbine 3, and this condensed water is boosted by the pump 5 and raised by the low-pressure feed water heaters 6, 7. It is heated and supplied to the deaerator 8, and then supplied again to the steam generator 1 by the water supply pump 9. The steam heated by the low-pressure feed water heaters 6 and 7 is normally supplied from the turbine 3, but when it cannot be supplied from the turbine 3, the steam may be supplied by bypassing the turbine 3. The drain of the low-pressure water supply heaters 6, 7 flows into the outlet side of the water supply heater 6 via the pipe 15 by the pump 14.

[0003]

In the conventional steam turbine as described above, the temperature of the condensate supplied from the deaerator 8 to the feed water pump 9 is the saturation temperature in the deaerator 8,
If the pressure in the deaerator 8 drops when the output of the turbine 3 suddenly decreases, it becomes difficult to secure the suction head NPSH necessary for the operation of the water supply pump 9. Therefore, as a countermeasure, increase the water storage capacity of the deaerator 8. Therefore, there are problems such as high cost and space requirement.

[0004]

A steam turbine plant according to the present invention is intended to solve the above-mentioned problems, in which condensed water sent from a condenser is heated via a water heater and then stored in a deaerator. In a steam turbine plant that supplies water to a steam generating means by a water supply pump, a configuration is provided in which a pipeline is provided for supplying drainage of steam after condensate is heated in the water supply heater to a water storage tank in the deaerator. And

[0005]

That is, in the steam turbine plant according to the present invention, the steam turbine in which the condensate sent from the condenser is heated through the feed water heater, is then stored in the deaerator, and is fed to the steam generating means by the feed pump. The steam drain after heating the condensate in the water heater in the plant is supplied to the water tank in the deaerator by a pipeline, and the steam drain after heating the condensate in the water heater. Since the temperature of the drain is lower than the temperature of the condensate that is heated by the water heater and stored in the deaerator, the drain of the steam discharged from the water heater is degassed when the pressure inside the deaerator decreases. By supplying water to the water storage tank in the vessel, the temperature of the condensate water stored in the deaerator is lowered and the suction head required for operating the water supply pump is secured.

[0006]

1 and 2 are explanatory views of a steam turbine according to an embodiment of the present invention. In the figure, the steam turbine according to the present embodiment is used in a nuclear power plant or the like, and as shown in the figure, the steam supplied from the steam generator 1 to the turbine 3 works in the turbine 3 and then the condenser. Condensed water is generated at 4, and the condensed water is supplied to the deaerator 8 after being increased in pressure by the pump 5 and heated by the low-pressure water supply heaters 6 and 7, and supplied again to the steam generator 1 by the water supply pump 9. The steam heated by the low-pressure feed water heaters 6 and 7 is normally supplied from the turbine 3, but when it cannot be supplied from the turbine 3, the steam may be supplied by bypassing the turbine 3. The drain of the low-pressure water supply heaters 6, 7 flows into the outlet side of the water supply heater 6 via the pipe 15 by the pump 14.

The temperature of the condensate supplied from the deaerator 8 to the feed pump 9 is the saturation temperature in the deaerator 8, and if the pressure in the deaerator 8 drops when the output of the turbine 3 suddenly decreases, etc. As it becomes difficult to secure the suction head NPSH required for the operation of No. 9, as a countermeasure against this, in this steam turbine, as shown in the figure, the drains of the low-pressure water heaters 6 and 7 join the water tank in the deaerator 8. A pipe line 17 is provided for lowering the temperature of the condensate water supplied from the deaerator 8 to the water supply pump 9 so as to operate the water supply pump 9.
PSH is secured. The pipe line 17 branches from the pipe line 15 provided on the discharge side of the pump 14 that feeds the drain discharged from the low-pressure water supply heaters 6 and 7, and reaches the water storage tank 19 in the deaerator 8. Valve 16 in line 15
However, valves 18 are provided in the conduits 17, respectively. A confluence device 20 is provided in the water storage tank 19 so that the condensate in the deaerator 8 and the drain from the pipe 17 merge and mix, and then are supplied to the water supply pump 9. . The confluence device 20 is provided with a large number of ejection holes below the annular pipe and directed obliquely downward to the inside. It has become so. The merging device 20 can have various shapes other than this.

Since the condensate supplied from the condenser 4 is heated by the water supply heater 6 and further heated by the water supply heater 7, it flows into the deaerator 8. The temperature of the drain discharged after heating the condensate inside is lower than the temperature of the condensate stored in the deaerator 8, and the valve 16,
18 is appropriately opened / closed to switch between the pipe line 15 and the pipe line 17, and the drain is connected to the water storage tank 1 in the deaerator 8 by the pipe line 17.
By supplying to the confluence device 20 in 9 and ejecting it from the confluence device 20 to condensate, the condensate in the water storage tank 19 and the low temperature drain are combined and mixed, and the condensate in the deaerator 8 Condensate having a low temperature can be supplied from the water storage tank 19 to the water supply pump 9. Therefore, when the pressure in the deaerator 8 drops, the temperature of the condensate supplied from the deaerator 8 to the water feed pump 9 is lowered in this way, and the suction head NPSH necessary for the operation of the water feed pump 9 is reduced. (Pushing pressure) can be secured, and the water storage capacity of the deaerator 8 can be made smaller than before.

[0009]

EFFECT OF THE INVENTION The steam turbine plant according to the present invention is configured as described above, and degass the steam drain after heating the condensate in the feed water heater when the pressure in the deaerator drops. By supplying the water to the water tank inside the device, the suction head required for the operation of the water supply pump is secured, so it is possible to make the water storage capacity of the deaerator smaller than before, and to reduce costs and save space. You can

[Brief description of drawings]

FIG. 1 is a flow system diagram of a steam turbine according to an embodiment of the present invention.

FIG. 2 is a sectional view of the deaerator.

FIG. 3 is a flow system diagram of a conventional steam turbine.

[Explanation of symbols]

 1 Steam Generator 3 Turbine 4 Condenser 5 Pump 6 Water Heater 7 Water Heater 8 Deaerator 9 Water Pump 14 Pump 15 Pipeline 16 Valve 17 Pipeline 18 Valve 19 Reservoir 20 Combiner

Claims (1)

[Claims] 1. A steam turbine plant in which condensed water sent from a condenser is heated via a water supply heater and then stored in a deaerator and is supplied to a steam generating means by a water supply pump in the water supply heater. A steam turbine plant comprising a pipe for supplying drainage of steam after heating the water to a water storage tank in the deaerator.