Inferential cascade control of multi-effect falling-film evaporator

Multi-effect falling-film evaporators are widely used in food and dairy industries. Due to the increasing application of multi-effect falling film evaporators, the tight control of these processes is very important. Because of large time delay and process disturbances, the robust and accurate control of total solid concentration in product is difficult. In this paper, by using inferential cascade control, the control of three-effect falling-film evaporator in Isfahan milk powder factory was discussed. It has been shown that by using linear Kalman filter and process measurements, total solid concentration of first effect product can be significantly estimated. The estimated state was used in inferential cascade control as secondary measurement. The results of inferential cascade control algorithm were compared with those of conventional feedback control algorithm.