August 20, 2019
Author: E. S. Beardwwod. NACE Corrosion 1989, Paper No. 313, NACE International, Publications Division, 1440 South Creek Drive, Houston, Texas, 77084, USA. www.nace.org.
ABSTRACT: On-line continuous feedwater monitoring has shown deviations from typical 10ug/L (10 ppb) or less oxygen levels in deaerator effluents. The higher oxygen levels have been incurred during the operational development of pressure and thermal gradient changes. These changes as well as operational upsets have been reported by others to lead to corrosion fatigue cracking in deaerators. Of course, disruption of deaerator internals have also been responsible for poor oxygen removal. This paper will discuss continuous oxygen monitoring in conjunction with heat and flow entities as applied to boiler feedwater deaeration and its improvement. Generalized rules and analyses of graphical trends will be developed. A procedural/problem solving check list for deaerator testing and operations will also be provided.