Reduction of Fouling During Product Processing Through Surface Modification Using Food-grade Coatings

摘要

Fouling of equipment is a serious problem in the food industry disrupting continuous production, causing equipment failure to deliver the required process conditions, and increase in the cost of production through increased utilization of energy, time, cleaning chemicals and water. Formation of foulants on the food equipment surface causes reduction in the heat transfer as well as increase in the pressure drop across the plate heat exchanger. Minimizing fouling is hence imperative to achieve better return on investment as well as to improve food quality. Modification of the stainless steel food equipment surface which comes into contact with the food product using food grade coatings is one method that could reduce fouling. A plate heat exchanger (PHE) system which operated in the recirculation mode was used to study the effect of surface-modified food processing equipment on fouling. Commercially available coatings were used to coat the stainless steel PHE plates. The PHE system was designed and installed in-house. Fluid skim milk at two different flow rates was circulated through the heating and cooling sections of the PHE unit continuously for about 6 hours. The milk was constantly heated to 72 deg C in the heating section and subsequently cooled down to 15 deg C in the cooling section prior to circulating again through the PHE unit At the end of the experimental period the amount of fouling occurring was determined. The amount of fouling occurring in the coated surfaces were compared with theamount of fouling observed on stainless steel surface to determine the effectiveness of surface modification techniques in controlling/minimizing fouling.