**3. Solving fouling problems by surface modification**

In a recent study, Nano-composite coatings were used to reduce fouling inside gasketed plate heat exchangers involved in food production. An antifouling coating with low surface energy (low wettability) led to a hydrophobic and oleophobic effect. The goal of the project was the application of new surface coatings (nanotechnology) to avoid or minimize adhesion, improve process management, simplify cleaning processes with lesser resources and chemical use, and increase the product reliability.

The test facility constructed by the Institute of Environmental Process Engineering (IUV) at the University of Bremen in Germany used for the investigation of milk adhesion and the stability of the coatings on small cylindrical ducts. A number of coatings and surface treatments were tested. A pilot plant including a milk pasteurizer at the Institute of Food Quality LUFA Nord-West in Oldenburg-Germany was used for the thermal treatment of whey protein solutions. Heat exchanger plates coated with different nano-composites as well as electropolished plates installed in the heating section of the pasteurizer were tested. Significant differences were observed between coated and uncoated plates. The coated plates showed reduced deposit buildup in comparison with the uncoated stainless steel plates. Polyurethane-coated plates exhibited the thinnest deposit layer. Electro-polished plates also reduced deposit buildup in comparison to the standard stainless steel plates and were almost comparable to the coated plates. The time required for cleaning in place (CIP) with the coated plates was reduced by 70% compared to standard stainless steel plates.
