Startup of distillation columns using profile position control based on a nonlinear wave model

Abstract

Startup of distillation columns is a very challenging control problem because of its strong nonlinearity and a wide operating range during the transient period. A nonlinear wave model captures the essential dynamic behavior of the distillation process so that it is possible to deal with the difficulties encountered during startup operation. This paper is concerned with the startup of distillation systems using nonlinear wave model based control developed by Han and Park (AIChE J. 1993, 39 (5), 787). This control scheme uses profile positions as controlled variables and is based on the nonlinear wave model by Hwang (AIChE J. 1991, 37, 705) and generic model control scheme by Lee and Sullivan (Comput. Chem. Eng. 1988, 12, 573). It can be applied to a binary or a multicomponent distillation system that can be represented as a pseudobinary. The proposed control scheme is shown by simulation studies to provide a safe and economic startup operation not only for dual composition control of a simple distillation column but also for a complex distillation configuration.