JPH04347490A - Drain processing device for steam plant - Google Patents

Abstract

PURPOSE:To prevent corrosion and the like in a steam generating device for a steam plant, which is generated by introducing impurities, such as iron series and the like which are removed from wet steam from a turbine and contained in drain. CONSTITUTION:Moisture in the wet steam of a high pressure turbine 2, driven by steam generated in a steam generating device 1, is removed by a moisture separator 3 as drain 12 while the exhaust steam of a low pressure turbine driven by the steam, whose moisture is removed already, is condensed in a condenser 6 and said drain and condensed water are circulated into the steam generating device 1 for a steam plant. The steam plant comprises a feed water heater 10, recovering the heat of drain removed from steam into water circulated to said steam generating device 1 and supplying the drain into the condenser 6, and a desalting device 8, provided at the down-stream side of the condenser 6 and removing impurities in water.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drain treatment device for a steam plant such as a nuclear power plant.

0002

2. Description of the Related Art A conventional drain treatment device for a nuclear power plant will be explained with reference to FIG.

1 is a steam generator; 2 is a high-pressure turbine driven by the steam generated by the steam generator; 3 is a moisture separator that collects moisture in the wet steam discharged from the high-pressure turbine 2 as a drain 12; 4; 5 is a heater that heats the steam from which moisture has been removed by the moisture separator 3; 5 is a low-pressure turbine driven by the steam heated by the heater 4; It becomes condensate. The condensed water passes through the pump 7, the desalination device 8, and the feed water heaters 9, 10, and 11 in sequence, and is then circulated as feed water to the steam generator 1.

On the other hand, the condensate 12 separated from steam by the moisture separator 3 is supplied to the feed water heater 11 through a tank 13 and a control valve 14, and is recovered. It is designed to circulate to the generator 1.

In this conventional drain treatment device, steam from a steam generator 1 performs work in a high-pressure turbine 2, and then becomes wet steam and flows into a moisture separator 3, where the moisture in the steam is removed. It is removed and becomes a drain 12, which passes through a tank 13 and a control valve 14 and is recovered by the water heater 11.

[0006] Also, the steam from which moisture has been removed in the moisture separator 3 is heated in a heater 4, does work in a low-pressure turbine 5, becomes condensed water in a condenser 5, passes through a pump 7, and is desalinated. After being purified by the device 8, the drain 1 is heated by the feed water heaters 9, 10, and 11, and then recovered by the water feed heater 11.
2 is supplied to the steam generator 1.

[0007]

SUMMARY OF THE INVENTION In the conventional drain treatment apparatus for a nuclear power plant described above, the drain from the moisture separator contains impurities such as iron. Since this drain is supplied to the steam generator via the feedwater heater, impurities in the drain are brought into the steam generator, causing problems such as corrosion of the steam generator.

The present invention aims to provide a drain treatment device for a steam plant that can solve the above problems.

[0009]

[Means for Solving the Problems] A drain treatment device for a steam plant according to the present invention uses a moisture separator to convert moisture in wet steam exiting a high-pressure turbine driven by steam generated in a steam generator into drain water. In a steam plant, the exhaust gas of a low-pressure turbine driven by steam from which moisture has been removed is condensed in a condenser, and the drain and the condensate are recycled to the steam generator, wherein the steam generator a water heater that recovers the heat of condensate removed from the steam and supplies the condensate to the condenser; and a desalination device provided on the downstream side of the condenser. We are prepared.

0010

[Operation] In the present invention, condensate containing impurities such as iron, which is removed from the humid steam of the high-pressure turbine in the moisture separator, exchanges heat with water that is circulated to the steam generator in the feed water heater, and the heat is recovered. The exhaust gas of the low pressure turbine is then fed to the condenser. Condensate from the low-pressure turbine exhaust generated in this drain and condenser is supplied to a desalination device, where impurities are removed and purified, and then circulated as feed water to the upper steam generator.

In this way, in the present invention, impurities such as iron in the water supplied to the steam generator are removed.
Corrosion of the steam generator is prevented.

0012

[Embodiment] An embodiment of the present invention will be explained with reference to FIG. This example relates to a drain treatment device for a nuclear power plant similar to that shown in FIG. 2, and the same parts are as follows:
In FIG. 1, the same reference numerals as in FIG. 2 are given, and the explanation thereof will be omitted, and the different parts will be explained below.

In this embodiment, the drain 1 removed by the moisture separator 3 is placed downstream of the control valve 14 connected to the tank 13.
A tank 15 is provided for receiving 2. The bottom of the tank 15 has a control valve 18 for controlling the water level of the tank 15.
It is connected to the water heater 9 through the tank 15, and the drain 17 in the tank 15 is supplied to the water heater 9.
Further, the drain coming out of the water supply heater 9 is supplied to the condenser 6 and recovered. In addition, the tank 1
The upper part of the tank 5 is connected to a feed water heater 10, and steam 16 from the tank 15 is collected by the feed water heater 10 and mixed with water supplied from the feed water heater 9 to the feed heater 10.

In this embodiment configured as described above, the drain 12 from the moisture separator 3 is flushed into the low pressure tank 15 connected to the feed water heater 10 via the control valve 14. The steam 16 is separated into a steam 16 and a drain 17 in the tank 15, and the steam 16 is sent to the feed water heater 10, where its heat is recovered by the water supplied to the feed water heater 10, and it is converted into steam together with the water supplied to the feed water heater 10. Generator 1
Circulate to.

On the other hand, the drain 17 in the tank 15 flows into the feed water heater 9 via the control valve 18, and after its heat is recovered by the feed water heater 9, it is recovered into the condenser 6. The recovered drain 17 is supplied to the desalination device 8 through the pump 7 together with condensate generated from the exhaust gas of the low pressure turbine 5 in the condenser 6 . Therefore, the impurities in the drain 12 generated in the moisture separator 3, that is, the impurities in the drain 17, are removed and purified by the desalination device 8 and supplied to the steam generator 1 as clean water.

As mentioned above, in this embodiment, the steam generator 1
The water supplied for circulation does not contain impurities such as iron, and corrosion of the steam generator 1 due to impurities can be prevented.

Note that the water level in the tank 15 is controlled to a predetermined water level by a control valve 18. Further, the water level of the drain 12 in the moisture separator 3 is maintained at a predetermined value by the control valve 14, and steam in the moisture separator 3 is prevented from flowing out to the tank 15. Furthermore, as described above, the water supply heater 1
The heat recovered by the water heater 9 and the water supply heater 9 is effectively used to heat water supplied from the condenser 6 to the steam generator 1.

[0018]

As explained above, according to the present invention, impurities such as iron contained in the drain from the moisture separator can be removed and purified by the desalination device. This can contribute to improving the health of the steam generator by preventing impurities from being brought into the generator.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an embodiment of the present invention.

FIG. 2 is a system diagram of a conventional drain treatment device for a nuclear power plant.

[Explanation of symbols]

1 Steam generator 2
High pressure turbine 3
Moisture separator 4
Heater 5 Low pressure turbine 6 Condenser 7
pump 8
Desalination equipment 9, 10, 11 Water supply heater 12 Drain 14 Control valve 15 Tank 16 Steam 17 Drain 18 Control valve

Claims (1)

[Claims] Claim 1: Moisture in wet steam exiting a high-pressure turbine driven by steam generated in a steam generator is removed as drain in a moisture separator, and a low-pressure turbine is driven by the steam from which moisture has been removed. In a steam plant in which the exhaust gas of a turbine is condensed in a condenser and the condensate and the condensate are circulated to the steam generator, the condensate removed from the steam is added to the water that is recycled to the steam generator. A drain treatment device for a steam plant, comprising: a feed water heater that supplies the drain from which heat has been recovered to the condenser; and a desalination device provided on the downstream side of the condenser.