Abstract
During commissioning of Industrial Cooling Water Systems, when make-up water is first circulated through equipments, the initial damage which occurs on metallic heat transfer surface is corrosion or flash corrosion. The flash corrosion must be controlled to prevent uneven growth of corrosion products else these will promote, in chains, layers of uneven corrosion product deposit, scale, foulants and microbiological foulants leading to choking and under deposit corrosion. The corrosion or flash corrosion in open recirculating cooling systems is prevented by a rigid, impervious and protective film. The concept of film formation versus film maintenance prevails since long in the field of Cooling Water Treatment Programme. Film formation (Pretreatment) is achieved by high level of chemical inhibitors/additives and film maintenance by low level of inhibitors (Regular Treatment). Based on experimental and field data new phosphate based Pretreatment and Regular Treatment have been developed and applied successfully to several Industrial Cooling Water Systems. The paper describes the Pretreatment and Regular Treatment process and field experience on their performance.
