Control of the azeotropic distillation process for separation of acetonitrile and water with and without heat integration

A novel acetonitrile/water azeotropic distillation scheme shows obvious economic advantages. It is of great significance to study the dynamic controllability of this process. In this work, the dynamic control structures of the non heat-integration and full heat-integration azeotropic distillation are studied. The control ability of the proposed control structures is tested by adding flow disturbance and composition disturbance. For the non heatintegration scheme, the conventional PID control structure and composition controller is used to achieve effective control when a disturbance occurs. For the full heat-integration scheme, the temperature difference control scheme and the composition controller are used to handle disturbances. This control structure reduces the stabilization time and makes the purity of the product return to the set value. The effect of different makeup flow on the purity of acetonitrile under different disturbances is discussed. Moreover, two control strategies are synthetically analyzed and compared by calculating integral of squared error. Considering economy and controllability, it is concluded that control strategy of heat-integrated azeotropic distillation has more advantages. This study has certain guiding value for the research of chemical dynamic control.