JPS628602B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steam turbine plant, particularly a PWR.
Concerning improvement of water supply quality for type nuclear turbine plants.

In conventional steam turbine plants of this type, the first
As shown in the figure, steam from a steam generator 16 is first introduced to a high-pressure turbine 1, and the steam output from the high-pressure turbine 1 is supplied to a low-pressure turbine 4 via a moisture separator 2 and a heater 3. From the low pressure turbine 4 are a condenser 5, a ground condenser 7, a condensate desalination device 8, a low pressure feed water heater 10, 11, and a deaerator 1.
2. The water is returned to the steam generator 14 through the high pressure feed water heater 13.

In such a conventional plant, the moisture separated in the moisture separator 2 becomes drain and is transferred to the deaerator 1.
2 was recovered during the main cycle. However, the condensate captured by the moisture separator 2 contains a relatively large amount of foreign matter (impurities) mainly composed of iron, and sending this condensate directly to the steam generator 14 may affect the quality of the water supply. This worsens and promotes tube corrosion (deposit attack) in the steam generator.

Therefore, it is necessary to remove impurities from this drain by some method before sending the water to the steam generator.

The object of the present invention is to improve the quality of this water supply and to minimize the decrease in efficiency of the turbine plant.

That is, the present invention provides a flash tank in the drain discharge system of the moisture separator disposed in the main cycle, and a first guide system that guides the steam generated in the flash tank to the low-pressure feed water heater. The steam turbine plant is provided with a second guide system for guiding moisture obtained in a flash tank to a condenser.

According to the present invention, the moisture separator drain is led to a flush tank, and the steam is led to a low-pressure feed water heater (one of multiple stages or two or more stages with a switching valve) for heat recovery, Water containing impurities is collected in a condenser, purified by a condensate desalination device, and then introduced to the main cycle water supply.

When collecting the condensate itself into a condenser,
Since the heat possessed by this drain cannot be recovered, the efficiency of the turbine plant is significantly deteriorated, but the present invention can prevent this and also minimize the mixing of impurities into the water supply.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to a preferred embodiment illustrated in FIG. 2 of the accompanying drawings.

Since the main cycle of the steam turbine plant shown in FIG. 2 is the same as the conventional one shown in FIG. 1, the same parts are given the same reference numerals and detailed description thereof will be omitted.

The difference from the system in Figure 1 is the moisture separator 2.
The process begins with connecting the drain pipe from the drain pipe to the newly installed flush tank 15 instead of leading it to the deaerator 12.

The steam generated in the flush tank 15 is guided to the low pressure feed water heaters 10, 11 via the first guide system or guide pipe 6. A drain switching valve 16 is arranged in this guide line 6 in front of each low-pressure feedwater heater.

The flash tank 15 is also connected to the condenser 5 by a second guide system or guide line 9.

The drain captured and separated by the moisture separator 2 contains impurities containing iron as a main component, which were present while passing through the cross-under pipe of the high-pressure turbine 1. This is led to the flash tank 15 and separated into water and steam, and the steam is sent to the low pressure feed water heaters 10 and 11.
Then, the water is recovered in the condenser 5.

By recovering steam to the low-pressure feedwater heater, the amount of air extracted from the turbine at that stage can be reduced, helping to prevent a drop in plant efficiency. In addition, since water containing impurities is recovered in the condenser 5 and all condensate is purified in the condensate desalination device 8, the quality of the water supplied to the steam generator 14 is lower than in the conventional system (Fig. 1). A significant improvement can be expected. The drain switching valve 16 is provided to provide flexibility in where steam can be recovered depending on the load of the unit and to maintain plant efficiency as much as possible over the entire load range.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a conventional steam turbine plant, and FIG. 2 is a similar diagram of a steam turbine plant of the present invention. 1...High pressure turbine, 2...Moisture separator, 3...
... Heater, 4 ... Low pressure turbine, 5 ... Condenser,
6...First guide system, 7...Ground capacitor, 8...Condensate desalination device, 9...Second guide system,
10, 11...Low pressure feed water heater, 12...Deaerator, 13...High pressure feed water heater, 14...Steam generator, 15...Flush tank, 16...Drain switching valve.

Claims (1)

[Claims] 1. A flash tank is installed in the drain discharge system of the moisture separator placed in the main cycle, and a first guide system that guides the steam generated in the flash tank to the low-pressure feed water heater and a flash tank A steam turbine plant comprising a second guide system that guides the obtained moisture to a condenser.