Heat Transfer Fouling: 50 Years After the Kern and Seaton Model

Fouling of heat exchangers is a chronic problem in processing industries. In addition to the appropriate selection of operating conditions and exchanger geometry, there are numerous chemical and mechanical methods to mitigate fouling and to remove deposits from the heat transfer surfaces. However, all methods to reduce fouling require some understanding of the mechanisms of the deposition process and of the structure and adhesion of deposits on the heat transfer surfaces. Almost exactly 50 years ago, D. Q. Kern and his co-author, R. E. Seaton, published a paper attempting to describe the growth of fouling deposits in terms of an unsteady-state heat and mass balance for the heat transfer surface. More or less at the same time, the TEMA fouling resistances were published based on operational and anecdotal evidence of fouling for a range of heat exchanger applications. These two approaches have since formed the basis for most heat transfer fouling models and heat exchanger designs. Increased costs of energy, raw materials, and production downtime have contributed to the growing interest in heat transfer fouling. More recently, environmental legislation has put additional pressure on fouling-related CO2 emissions and disposal of cleaning chemicals. Despite these efforts, fouling of heat exchangers is still far from been understood in its whole complexity. The present paper documents the 2009 D. Q. Kern Award Lecture in which some selected aspects of fouling research to date have been presented and areas have been identified where significant research and development activities are still required.