EVAPORATOR PROCESS-CONTROL USING COMPUTER-MODELS

Model-based control is the concept of using a real-time mathematical model to adjust inputs to a process in order to achieve control objectives. The current study of its application to evaporators was conducted in conjunction with two Australian food processing factories. The potential benefits include greater process flexibility and better response to setpoint variation. Data from the two evaporation systems collected over two years included evaporator design and configuration, product thermophysical data, and system performance data. Two computer models based on heat and mass balance and heat transfer were constructed using a modular programming style which allowed system reconfiguration. The model was validated using plant data from one factory, the difference with the simulation model being not significant at the 5% level. Methods for combining the predictive capacity of the model with a standard control algorithm are discussed, as well as the validity of this control approach for dynamic situations such as start-up.