Method of water treatment in steam plant

Abstract

In a steam plant, the amount of chemicals, such as hydrazine, used is minimized so as to prevent any sticking of scale in specified equipment. During the operation of the steam plant, temporary chemical environmental change or approximately periodic chemical environmental variation is applied to flow channel (21) within given equipment.

Description

technical field [0001] The present invention relates to a water treatment method used in steam facilities such as atomic energy or thermal power generation. In particular, the present invention relates to a method for preventing scale from adhering to water supply pumps, drainage pumps, water supply booster pumps, heaters, orifices, control valves, etc., which are installed on the flow path of the circulation system of a steam facility and where scale adhesion is a problem. Steam facility water treatment methods. Background technique [0002] For example, in a jet boiler of a steam facility for thermal power generation, the cleaner the water quality of the supply water, the more wavy scale tends to be formed on the inner surface of the evaporator tube, and the wavy scale causes an increase in the jet loss of the jet boiler. [0003] As a method for reducing this wavy scale by water treatment, the following methods have been proposed: a method of increasing the concentration...

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Problems solved by technology

Therefore, for example, there are problems in that the differential pressure rises due to protruding or wavy scale deposits on the steam vent hole of the steam generator, and the differential pressure rises due to wavy scale deposits on the flow surface of the orifice and the nozzle part of the flow meter. Adhesion of wavy scale to the inner surface of the thin tube in the feed water heater causes an increase in differential pressure, and adhering of wavy scale to the turbine part of the feed water pump causes an increase in the amount of drive steam or an increase in the current value of the drive motor

[0016] In addition, hydrazine is used in the methods disclosed in the above-mentioned Patent Document 1 and Patent Document 2, but hydrazine is relatively expensive and the impact of hydrazine on the environment is also worthy of attention. Require

[0017] On the other hand, in the methods disclosed in the above-mentioned Patent Document 3 and Patent Document 4, an oxidizing agent is used. However, when the oxidizing agent is injected into the feed water, measures for improving the durability of the secondary system equipment are required separately. Therefore, Its status quo is difficult to apply to nuclear energy facilities

[0018] In addition, in the centrifugal pump used for the water supply pump, since the water in the gap between the surface of the impeller opposite to the surface of the water introduction side and the inner surface of the volute is difficult to flow out to the outside, there will be water stagnation. Scale tends to form on the surface of the impeller in contact with the water stagnant in the gap, and this scale causes a decrease in the efficiency of the centrifugal pump.

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