Ten Years of EquilibriumPhosphate Treatment

摘要

This paper reviews the undamentals of phosphate based boiler water alkalinity control, including conditions which may lead to caustic or phosphate induced corrosion. Relevant field and laboratory data are reviewed and limits of safe operation are defined. As a result, Equilibrium Phosphate Treatment (EPT) is recommended as the preferred treatment for drum boilers, which can tolerate solid alkali. A case is also made for replacement of the current concept of generic "remote" boiler water chemistry control, based on pH and phosphate concentration measurements, with boiler specific, pressure and/or load dependent pH and cation conductivity control curves.