Fouling mitigation in food processes by modification of heat transfer surfaces: A review

In most industrial processes, heat exchangers are used for preheating, condensation and evaporation. Within these apparatuses, undesirable deposits often form. These deposits are known as fouling and cause a multitude of operational problems, such as a reduction in heat transfer, an increase in the pressure drop or a contamination of the product. Likewise, more frequent cleaning cycles are necessary to comply with hygiene standards. In view of the technical and economic requirements, strategies to reduce fouling are increasingly important. The modification of the surface of a heat exchanger offers a suitable means to reduce fouling. This review presents the current state of research concerning the influence of modified surfaces on fouling and cleaning in the food processing industry, with a focus on the energetic characteristics of different surfaces and their interactions with soilants. A special emphasis is placed on mineral and organic deposition as an essential part of food fouling. The goal is to establish a strategy for assessing the surface modifications that can mitigate complex food fouling. The chemical, thermal and mechanical resistance of coatings are evaluated based on the currently available literature. Finally, practical experience and economic considerations that contribute to a holistic view of fouling and cleaning processes are appraised, and the need for further research is addressed. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.