Energy savings encountered due to food processing equipment surface modification-Investigation under industry-comparable process conditions

A pilot-scale plate heat exchanger system having modified surfaces was tested for possible thermal energy savings while processing milk and tomato juice at pasteurization temperatures. The surfaces tested were stainless steel 316 (control), and SS-316 coated with one of three different commercially available food-grade materials; Lectrofluor-641™, TM-117P (graded Ni-P-PTFE), and AMC148-18. The PHE system was operated continuously for 6 h at two different flow rates, 0. 162 and 0.144 m³/h/channel. The total thermal energy consumed (ignoring the radiation losses) whije using the Lectrofluor-641™ coated plates results in about 7.68% and 15.86% less energy consumption respectively, for processing tomato juice and skim milk at the higher flow rate than when traditional SS-316 plates were used. Using graded Ni-P-PTFE coated plates in the PHE system also resulted in lowering the thermal energy utilized during processing skim milk and tomato juice though at a lesser percentage compared with Lectrofluor-641™ coated plates. Reducing the flow rate resulted in increased fouling, and increased use of thermal energy for processing tomato juice while using the coated plates. However, for skim milk pasteurization the energy required decreased when the flow rate was reduced in spite of the increased amounts of fouling produced. Future tests are planned to be conducted using more coated plates in the PHE unit and under extended periods at industry comparable processing conditions to accurately determine the thermal and electrical energy savings encountered.