An Impact on Plant Performance from Advanced Instrumentation

Harpster, J.W.
“An Impact on Plant Performance from Advanced Instrumentation”  ISA POWID Industry Symposium, Orlando, FL, July 7-13, 2001.   Best Technical Paper Award

Abstract

The importance of advanced instrumentation to directly measure assumed or unknown subsystem properties or characteristics of power plants, operating within the current market, is presented.  These measurements are needed to quantify critical parameters, not only in units with older control hardware, but also for those equipped with modern information systems, which may or may not contain simulation computations, for plant control and management.  One such measurement is air in-leakage into the shell side of a steam surface condenser.  This measurement, along with an understanding of its response to behavior of steam and non-condensables within the condenser space, is discussed.  This understanding provides the foundation for a comprehensive theoretical treatment of how air behaves in a condenser, and its effect on condenser performance.

The use of RheoVac® air in-leakage and condenser diagnostic instrumentation will be presented.  This instrument provides the ability to measure properties of the gases entering the vent line from the air removal section of a condenser.  It will be shown that these data, along with other condenser operating parameters, can be combined to describe air passage within the condenser. Also described are the performance characteristics of the condenser as they are affected at different levels of air ingress.  The impact of air in-leakage on excessive sub-cooling, resulting in high dissolved oxygen, will be presented.  A practical control point for maintaining air in-leakage in operating plants will be argued from the viewpoint of minimizing dissolved oxygen and improving heat rate.