Sequential Events in Heat Exchanger Fouling: Initiation, Transport, Attachment, Removal, and Aging
Heat Exchanger Fouling: Detailed Sequential Events Sequential Events in Fouling From the various fouling mechanisms , it is clear that virtually all these mechanisms are characterized by a similar sequence of events. The successive events occurring in most cases are the following: (1) I nitiation , (2) Transport , (3) Attachment, (4) Removal , and (5) Aging , as conceptualized by Epstein (1978). These events govern the overall fouling process and determine its ultimate impact on heat exchanger performance. In some cases, certain events dominate the fouling process, and they have a direct effect on the type of fouling to be sustained. Let us summarize these events briefly (Cannas, 1986). Initiation of the fouling, the first event in the fouling process, is preceded by a delay period or induction period Td . The basic mechanism involved during this period is heterogeneous nucleation , and Td is shorter with a higher nucleation rate. The factors affecting Td are temperature, fluid v...