Temperature Histories in a UHT Indirect Heat Exchanger

An indirect UHT processing system was modeled by a computer program to predict the temperature profile of a mass element of fluid as it progressed through heating, hold and cooling units. The computer program consisted of successive calculations of the temperature at the exit of numerous increments in each unit based on the overall heat transfer coefficient determined for the total length of the unit. The validity of the computer program was determined by correlation of computer results with experimental determinations of sucrose inversion. The percentage of total inversion of sucrose occurring in the heater was 36%, indicating the error associated with the assumption of chemical reactions based exclusively on hold tube temperature, residence time and laminar flow pattern.