Investigation of Whey Protein Deposit Properties Using Heat Flux Sensors

Heat exchanger fouling due to whey proteins was investigated in a concentric-tube device using aqueous solutions of 3.5 wt% whey protein concentrate.The void (liquid) fraction of the deposit changed as the fouling mechanism changed from surface reaction control to mixed bulk reaction and mass transfer control. The thermal resistance of deposits and their effective thermal conductivity was measured in situ using a novel technique based on a heat flux sensor. This method gave values of (effective deposit thermal conductivity×density, ρ f λ f) around 470Wkgm−4K−1 for deposits exposed to wall temperatures less than 85° C. Deposits formed at higher wall temperatures showed the effects of ageing and gave a larger value of ρ f λ f.