Multi Effect Falling Film Evaporators Control Using Hybrid Structure of PI and LMPC

Due to sensitivity of organic compound in milk to heat and evaporation process, milkusually concentrates in equipments with low residence time and high efficiency such as falling film evaporator. Generally, in this process due to large time delay and disturbances, the tight exact and proper control of product concentration is difficult and important. In this study, to improve the controller performance in falling film evaporator process and elimination of controller offset, a proper structure consists of LMPC and PI controller is proposed. First, a three-effect falling film evaporator is modeled and simulated at dynamic state and then, the proposed control algorithm is applied on process and results of proposed hybrid method are compared with results of conventional PID control. The Simulation results showed that the proposed structure is significantly capable in control of outlet concentration from multi effect falling film evaporators.