F-5 Organic Fouling - The State of the Art

G. Breber

This report describes and summarizes the A. P. Watkinson's study, "Critical Review of Organic Fluid Fouling: Final Report" (88). The premise of this report is that only through an understanding of the mechanism of the chemical and physical process involved in organic fluid fouling of heat transfer surfaces can rational steps be taken in the design and operation of industrial heat exchangers in order to control or reduces the economic penalties associated with fouling. Reduction of fouling has the potential to save substantial amounts of energy, as well as capital and other operating costs. This critical review was undertaken to provide a current summary of what is known about organic fluid fouling of heat transfer surfaces, and to recommend directions for needed research.

Organic fluid fouling usually involves a two-step chemical process in which soluble precursors are first formed, and the a precipitation of a higher molecular weight polymerized product occurs. The insoluble species may be produced in the fluid or at the heat exchange surface. This review shows that generation of precursors in aerated organic fluids occurs primarily by autoxidation at temperatures below 650 °F (343 °C), or by thermal decomposition at higher temperatures or in the absence of oxygen. Subsequent precipitation occurs following polymerization of the precursors. Since the same kind of reactions are involved in the fouling of many organic fluids, a general understanding of the organic fluid fouling process may be obtained without studying an inordinately large number of different fluids.