CONDITIONS FOR THE INTRODUCTION OF OXYGENATED FEED WATER TREATMENT PLANTS AND CHEMICAL CLEANING

摘要

Oxygenated feed water treatment is one of the methods of boiler feed water treatment that has been introduced in thermal power plants mainly for the purpose of improving the economical efficiency. This is achieved through a reduction in the boiler feed water pump (BFP) drive force and the extension of the chemical cleaning intervals, by means of restraining the growth rate of the scale on the boiler tubes. Chubu Electric Power Co., Inc. has introduced one type of oxygenated feed water treatment, called "Combined Water Treatment (CWT)", into nine of its once-through boiler units, and has obtained the required results in areas such as a reduction in the iron concentration in the boiler water, the suppressing of the increase in the apparatus differential pressure, and a reduction in the amount of scale depositing to the tubes.rnChubu Electric is currently examining a method to forecast the scale growth in a CWT plant and to determine the time to conduct chemical cleaning, based on measurements of the thermal conductivity of the scale produced while using the CWT method (CWT scale) and understanding the changes in the scale amount and thickness over a period of time. This paper describes the conditions for an introduction of CWT and the chemical cleaning program at Chubu Electric.