JPH01162193A - Control of dissolved oxygen in feedwater heater drain - Google Patents

Abstract

PURPOSE:To decrease a concentration of dissolved oxygen without a significant heat loss, by detecting the concentration in a drain with a concentration detector of dissolved oxygen, by changing a water level in a drain tank through a regulating valve operation and by controlling a falling height of the drain water. CONSTITUTION:A steam condensated by a high pressure heater 10a is drained and led to a drain tank 11 and then is again led to a feed water system via a drain cooler 16 by a drain pump 13. A concentration of dissolved oxygen in a drain at an outlet piping of the cooler 16 is detected with an oxygen concentration detector 12 and therewith a water level inside the tank 11 is changed by controlling of a regulating valve 17 to control a falling height of the drain water. Thereafter, a concentration of dissolved oxygen in the heater drain is reduced without any significant heat loss.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heater drain pump-up system for a boiling water nuclear power plant, and particularly relates to a dissolved oxygen control device suitable for controlling dissolved oxygen concentration in a heater drain. .

[Conventional technology]

As described in Japanese Patent Application Laid-Open No. 55-142285, the conventional device extracts the vent from the heater drain pipe and collects the vent into the condenser.

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, the vent is extracted from the heater drain pipe and recovered to the condenser, but no consideration is given to the heat loss caused by this, and there is a problem of a decrease in plant thermal efficiency.

Furthermore, in the heater drain pump-up system, it was not possible to directly pump up the drain due to the high concentration of dissolved oxygen in the drain.

An object of the present invention is to reduce the dissolved oxygen concentration in the heater drain system without heat loss, and to pump it up directly in the heater drain pump-up system.

[Means for solving problems]

The above object is achieved by changing the water level in the drain tank depending on the dissolved oxygen concentration in the heater drain to control the height of the drain.

[Effect]

The dissolved oxygen concentration detector installed on the outlet piping of the drain cooler detects the dissolved oxygen concentration in the drain and controls the control valve to change the water level in the drain tank and control the height of the drain. Dissolved oxygen concentration can be reduced without heat loss.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure shows a system diagram of a heater drain dissolved oxygen control system in a power plant. The steam condensed by the high-pressure heater 10a becomes drain, and is led to the drain tank 11, and the drain cooler 1
6 and is led to the water supply by a drain pump. In such a system configuration, the dissolved oxygen concentration in the drain of the outlet pipe of the drain cooler 16 is detected by the oxygen concentration detector 12, and the water level in the drain tank 11 is changed by controlling the control valve 17. Control the height of water fall.

According to this embodiment, the dissolved oxygen concentration in the heater drain can be reduced. 15 in the figure is a water level detector.

Figure 2 is a schematic system diagram of a power generation plant, in which 1 is a steam generator, 2 is a steam turbine, 3 is a condenser, 4 is a condensate pump, 5 is an air extractor condenser, and 6 is a ground. A steam condenser, 7 a condensate purification device, 8 a low pressure heater, 9 a water supply pump, 13 a drain pump, and 14 a generator.

〔Effect of the invention〕

According to the present invention, the dissolved oxygen concentration can be reduced without heat loss in the plant, and the heater drain pump-up system can directly pump up the drain, thereby improving efficiency.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a dissolved oxygen control device according to an embodiment of the present invention, and FIG. 2 is a schematic system diagram of a power generation plant. 12...Oxygen concentration detector, 13...Drain pump,
14... Generator, 15... Water level detector, 16...
Drain Figure 1 Figure 2

Claims (1)

[Claims] 1. Steam generated from a steam generator is led to a steam turbine, drives the turbine and a generator connected to it, is condensed in a condenser, and is heated in a feed water heater; In a power generation plant that supplies water as feed water to the steam generator, a control valve is provided in the middle of a pipe that guides steam as a heating source of the feed water to the feed water heater and discharges condensate condensed through heat exchange with the feed water. and a dissolved oxygen meter, and controls the dissolved oxygen in the drain by controlling the control valve based on a signal from the dissolved oxygen meter.