Comparison of Dynamic and Static Performances of a Quaternary Distillation Sequence

In this work, steady state and dynamic performances of quaternary distillation column sequences designed based on steady state and dynamic cost functions have been investigated. To quantify the dynamic performance, product losses due to disturbances have been considered in the objective function. In addition, variations of operating costs such as utilities have been considered in the objective function. To separate a quaternary mixture into four products, 22 configurations have been used. It has been observed that the feed composition, disturbance frequency and magnitude affect the dynamic behavior strongly. To decrease the optimization computational load, a scheme that provides a suboptimal result has been proposed. By performing simultaneous optimization that requires much more computational time, it has been shown that the highest ranking configurations obtained by the proposed method are the same as those provided by simultaneous technique. The simulation results indicate that there is no clear pattern for configuration ranking based on column sequence specifications.