Tubular Heat Exchanger Fouling by Milk During Ultra High Temperature Processing



    1. Author Swartzel is affiliated with the Depts. of Food Science and Biological & Agricultural Engineering, North Carolina State Univ., Raleigh, NC 27650.
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  • The author gratefully acknowledges the financial support of Dairy Research, Inc. (Rosemont, IL) and the equipment support of Cherry-Burrell (Cedar Rapids, IA). A special appreciation is extended to Mr. R.R. Earley (NCSU dairy plant manager) for his continued support and patience, and to Mr. R.B. Biziak for his valuable contribution to the system operation of this study.


The effect of milk fouling deposits on the heat transfer rate of a tubular heat exchanger was investigated for varying process heat treatments. Product input and discharge temperatures were maintained constant while steam temperature increased as deposits formed. Processing conditions included product entrance temperatures of 347.6 and 366.4°K for heater exit temperature of 410.7°K and product velocity of 1.58 m/s; 363.9 and 366.7 for 410.7 and 2.70; 364.6 for 410.7 and 3.25; 370.6 and 357.8 for 427.4 and 1.58; 378.5 for 427.4 and 2.70; and 379.5 and 376.3 for 427.4 and 3.25. Predictive expressions representing product deposition were determined for process variables, heating curve variables, and equivalent times and temperatures representing the thermal treatment. Product constituent losses during the fouling process and aspects of fouling kinetics were examined.