Dynamics and control of falling film evaporators with mechanical vapour recompression

Abstract

Develops and analyses a model of a falling film evaporator with mechanical vapour recompression for the purpose of examining the coupling and functional controllability of the two core control loops for effecting temperature and product dry mass fraction. The relative gain array is used to assess coupling and the functional controllability analysis uses the methodology of Skogestad and Postlethwaite (1996). This determines if adequate levels of disturbance rejection can be achieved with allowable levels of manipulation. The aim is to understand the fundamental properties of the process which limit the ability of the control system to reject disturbances. A first principles model of appropriate complexity which captures the essential mechanism is developed and used.