Role of electrokinetic properties of corrosion products in prevention and controlling deposition in water/steam cycle of thermal power plants

Abstract

One of the foremost concern in thermal power plants is the formation of deposits of corrosion products in diverse areas of the water/ steam cycle. This deposition process causes local overheating and rupture of boiler tubes, damages of turbines and other segments of power units, that ultimately leads to sizable efficiency loss. The corrosion products are metal oxides usually present in colloidal form and tend to precipitate on the heat exchange surfaces. In this paper a new approach to prevention deposit using electrokinetic properties of colloidal particles is discussed. The mechanism of deposition formation is outlined considering the role of electrostatic interactions between the steel wall surface and colloidal particles. Furthermore, utilization of zeta potential data in deposit predicting and control is thoroughly elucidated. It was inferred that described concept is applicable in power industry through changing electrokinetic potential of colloidal particle what is attainable either by modification of structure of adsorption layer of metal oxide particles or by altering pH of boiler water. It was stated that exploiting surface properties of corrosion product for controlling and mitigation deposition in power chemistry circuits may have a huge benefit for power plants improving their availability, reliability and performances.