Optimisation of an Agitated Thin Film Evaporator for Concentrating Orange Juice Using Aspen Plus

Abstract

AbstractThis paper presents an application for the optimisation of an existing agitated sdthin film evaporator (ATFE) for concentrating orange juice using Aspen PlusTM. A rigorous heat exchanger mode (Heatx) and a rigorous two‐phase flash model (Flash2) were used to simulate the dominant effects of the ATFE. The thermo‐physical properties of orange juice, not available in Aspen Plus, were determined experimentally and correlated as functions of temperature and solids content by Boonsriudomsuk [1]. Effective heat transfer coefficients were calculated from measured temperatures and flow rates.Experiments were performed on a laboratory‐scale and pilot plant system and compared with the simulation results. The Aspen Plus simulation model using experimentally determined heat transfer coefficients and thermo‐physical properties of orange juice compared well with the experimental data from the ATFE. When the mass and energy balance data were reconciled the errors between both experimental and simulation results were significantly decreased.The optimisation results indicated that by operating at the optimum operating conditions the operating costs could be reduced by about 10%. This translates into savings of more than $10.000/vear in the case of the laboratory‐scale evaporator and $33,000/year in the case of the pilot plant. If a commercial ATFE process was optimised then the potential savings could approximate to $330,000/year. Clearly, process optimisation is a valuable tool in the design and operation of these processes.