The Use of Comparative Modelling on Heat Exchangers in Cooling Water to Avoid Unscheduled Production Downtime

August 19, 2019

Author: E. S. Beardwood. Heat Exchanger Fouling and Cleaning, Dublin, Ireland, June 7-12, 2015., now operated by HTRI (Heat Transfer Research Incorporated)

ABSTRACT: The global economy has forced a shift in the 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 profitability. 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. The modeling allows one to make fundamental changes in either heat exchanger operational conditions or cooling water chemistry or both where needed. This approach was applied to a chemical processing plant’s cooling system resulting in an extension of “time to tube leaks” and heat exchanger bundle life, while avoiding unscheduled, forced outages for repairs. Tube leak rates of 7 per year were reduced to 1 per 36 months and bundle life from 6 months to a year were extended to a prorated 13.5 years based upon the actual type and rate of corrosion compared to an ideal target of 17.