The global economy has forced a shift in emphasis from preventative maintenance to risk based maintenance with expectations of extending the time between scheduled outages such as turnarounds, while also moving towards longer duration between unscheduled downtime in an effort to increase today’s profitability. Utilization of an ROI-based evaluation to schedule maintenance compared to the offset in production throughput at times have been wise decisions and at other times not so wise. As the decisions are one of risk versus reward, an organization may at some point be confronted with an unscheduled outage in the wake of a decision made well in the past that negatively impacts profitability today or in the future. Clearly, there had been either confusion or a misunderstanding in regard to the complexities associated with both the risks and rewards.

This paper will discuss the best practices associated with the water treatment and performance management of cooling waters on a holistic basis. This will allow for better definition of the risks in order to ensure the reliability required to obtain the rewards sought by management. Cooling system design compared to actual operational conditions may not approach best practice; hence predictions using modeling to identify potential areas susceptible to failure and then monitoring techniques to predict the health and performance of said cooling system unit operations are outlined to assist in defining the risks and rewards. Case histories are also provided.

Key Words: Cooling water, heat exchangers, skin temperature, residence time, hydraulic balance, hydrothermal stress, velocity, pretreatment, process inleakage, contingency treatment approaches, fouling, general and localized corrosion, biological control, monitoring, modeling.