REDUCING STATIC DEVIATIONS OF PRODUCT QUALITIES IN THE TEMPERATURE CONTROL OF AN IDEAL HEAT-INTEGRATED DISTILLATION COLUMN

Two strategies are proposed in this work for the reduction of static deviations of product qualities in the dual-point temperature control of a simulated ideal heat-integrated distillation column. The key to achieve this purpose is to sense the changes in operating conditions and make appropriate adjustments simultaneously to the set-points of the top and bottom control loops. The first method is based on the inferential signals extracted from the composition of products and the second one from the temperatures of the top and bottom stages. Both strategies are intensively studied through the operation of the simulated ideal heat-integrated distillation column separating a binary equimolar mixture of benzene and toluene, and it is found that they could work effectively to decrease the static deviations in product qualities. The strategies are characterized by great simplicity in principle and a relatively small effort in process modeling, thereby allowing wide applications in the operation of various distillation columns with a dual-point temperature control scheme.