METHOD AND SYSTEM FOR CONTROLLING WATER QUALITY IN POWER GENERATION PLANT

摘要

A method for controlling water chemistry in a power generation plant including a low-pressure feedwater heater (18), a deaerator (19), and a high-pressure feedwater heater (20) disposed sequentially along a feedwater pipe (16) from a condenser (15) to a steam generator or a boiler (11) to control the chemistry of feedwater guided to the steam generator or the boiler includes the steps of: injecting an oxidant through an oxidant injection line (31) into feedwater flowing through the feedwater pipe disposed downstream of the condenser in such a way that a dissolved oxygen concentration in the feedwater ranges from 3 to 100 ppb while the feedwater is maintained to be neutral to form an oxide film on surfaces of the feedwater pipe, the low-pressure feedwater heater, the deaerator, the high-pressure feedwater heater, and other structural members that come into contact with the feedwater; and injecting a deoxidant through a deoxidant injection line (35) into the feedwater flowing through the feedwater pipe disposed downstream of the deaerator in such a way that the dissolved oxygen concentration in the feedwater flowing into the steam generator or the boiler lowers to 5 ppb or lower.