Optimization of cleaning schedule of heat exchanger networks undergoing fouling considering maintenance constraints

Fouling of heat exchangers is one of the most common and unavoidable problems faced by process industries (Georgiadis and Papagorgiou, 2000). The deposition of foulants results in the gradual reduction of the overall heat transfer rate and increased pressure drop in each heat exchanger, which affects the thermal and hydraulic performance of the entire heat exchanger network (HEN). This results in increased pumping cost and extra thermal load on the utility system. Since the presence of foulants cannot be prevented entirely, heat exchangers must be cleaned occasionally to restore their effectiveness and avoid critical failures. The costs from additional pumping power and utility requirements, cleaning, and related business losses translate to millions of dollars every year for the process industries (Macchietto et al., 2011, Müller-Steinhagen et al., 2005). This paper seeks to propose the methodology which gives optimal cleaning schedules and operating conditions for the HENs with minimum maintenance interventions.