The costs caused by the process related formation of deposits on heat transfer surfaces are in the order of 40,000 million dollar U.S. per year, for the total industrialized world! Despite increased attention during the past two decades, the allowance for fouling is still the most underestimated problem in the design of heat exchangers. Further refinement of heat exchanger design procedures will only be possible in conjunction with more sophisticated methods to include the effects of fouling. While the installation of excess heat transfer surface may extend the operation time of heat exchangers, it provides no remedy against the deposition of dirt.
Heat exchanger fouling can be reduced by proper heat exchanger design, appropriate selection of heat exchanger type and by mechanical and/or chemical mitigation methods. All methods require an understanding of the mechanisms of dirt deposition and of the influence of operating parameters on the deposition rate. In this key-note paper, results of numerous experimental and theoretical investigations during the past 10 years are presented. These investigations have been performed with model or industrial fluids in laboratory or plant equipment. The state-of-the-art in fouling mitigation is reviewed and attention is drawn to areas where future academic and industrial research is required.