Fouling Free Surface

PHEs (Plate Heat Exchangers) are widely used since they exhibit excellent heat transfer characteristics which allow more compact designs than are achievable with conventional shell and tube heat exchangers. Along with their easy maintenance and other advantages, the PHEs have become the prime choice for the dairy and food processing industries due to their relative ease of cleaning (compared with tubular type) and their thermal control characteristics required for sterilization or pasteurization purposes. Even so, fouling is a severe problem causing significant capital and operating costs. In the dairy industry, the cleaning of the heat exchanger is typically conducted every 5-10 hours using clean water and chemicals. The increase in electrical energy consumption in US pasteurized liquid milk industry alone due to fouling is estimated at 92 million kWh per year and the increase in thermal energy consumption at 39 million therms during the year 1990-91. Fouling increases costs of food plant operations by requiring oversized equipment, increased downtime, increased energy, water and chemical consumption for cleaning. Fouling was estimated to cost the US pasteurized liquid milk industry alone $104 million in 1991. The proposed surface treatment concept using carbon nanotubes will be investigated to try to develop a non-sticky surface, which will reduce the initial capital cost and the ongoing operating costs in the milk pasteurization industry.