Performance analysis of the milk concentrating system from a Brazilian milk powder plant

Abstract

The steady-state operation of the concentrating system from an industrial milk powder plant was studied using a simulation approach. This system is composed of two tubular preheaters, a plate pasteurizer, a thermocompressor and four climbing-falling-film plate evaporators operating in a multiple-effect arrangement. Its simulation was performed using the ASPEN Plus shell, into which calculation routines previously developed by the authors had to be introduced in order to enable the calculation of the plate units. For the thermocompressor, a simulation code based on the solution of a design equation and the overall mass and energy balances was formulated and then introduced into ASPEN. In the validation step, simulation results were compared with operating data of the industrial plant, and a good agreement was verified. A sensitivity analysis of the concentrating system was then performed, considering two different operating variables, namely the milk inlet temperature and the motive steam pressure in the thermocompressor.