OPERATING AN IDEAL HEAT-INTEGRATED DISTILLATION COLUMN WITH DIFFERENTCONTROL ALGORITHMS

The operation of an ideal heat integrated distillation column is addre ssed Five control strategies, namely, single loop composition control system, multi-loop composition control system, multivariable internal model control (IMC) system, modified multivariable IMC control (MIMC) system and nonlinear process model based control (NPMC) system, are de sign and applied to the process. Simulation results demonstrate that a ll the control systems are capable of keeping both end products on the ir specifications. The NPMC is the best one in the operation of the id eal HUDiC. It can very smoothly realize setpoint transition and effici ently counteract external disturbances. The MIMC ranks the second for the regulatory responses to feed composition disturbances have relativ e longer setting time. The next comes to the multi-loop composition co ntrol system. Although it works well for the operation of the ideal HI DiC, it produces relative larger oscillations and longer setting time in the system responses. The IMC can not compete with the multi-loop c omposition control system because it is extremely sensitive to operati ng condition changes. The single-loop composition control system is th e worst one for the responses of the uncontrolled product is extremely sluggish. (C) 1998 Published by Elsevier Science Ltd. All rights rese rved.