Not only does CWT(Combined Water Treatment), one of new boiler water treatment methods, inject a small amount of oxygen to control corrosion in the water system by generating scale (hematite) as protective coating, it also injects ammonia to obtain pH8 to 9 feedwater.
As a joint research with Chubu Electric Power Co., Inc., the CWT was introduced to Chita No.2 Thermal Power Plant of Chubu Electric Power Co., Inc. in Aug.1990 for the first time in Japan as a system for utility plants.
Since then, the effectiveness of the CWT has been field-proven, and now adoption of the CWT is being advanced in many places in Japan.
The CWT is effective for a boiler in normal operation, and it is required to use it together with the volatile material treatment method(AVT) at start-up, shutdown or during storage. Hitachi, Ltd. and Babcock-Hitachi K.K. have acquired a patent on operation of CWT.
Patent Number 2512728 "Boiler Feedwater Quality Adjustment System"
