Conference Dates

July 1-6, 2007

First Page



Heat transfer fouling experiments were carried out in a temperature controlled stirred vessel using aqueous solutions of whey protein concentrate in the concentration range of 3 to 3.5 wt-% at a bulk temperature of 50 °C and pH of 6. Heat transfer data were obtained from thermocouples embedded in an immersed electrical heating rod with various metal plates attached with-and-without surface treatments. Measurements included solution temperature, heating element surface temperature, and heat duty. Results are presented as fouling resistance versus time for aluminum, copper, stainless steel, electro-polished stainless steel, and surfaces coated with DLC and doped with Si , SiO, as well as DLC-coating of an electro-polished stainless steel. Reducing surface roughness was found to mitigate fouling but the combination of both surface treatments, DLC coatings, and electro-polishing gave the best performance. The experimental results demonstrate the potential and value for reducing the adhesive behavior of whey protein fouling layers using modified surfaces. Also a comparison of these results with those for crystallization fouling show the same effects of the surface modification on nucleation and crystal growth. Of particular importance is the influence on the cleaning performance where the main potential can be expected.