Effect of recycle structure on distillation tower time constants

Abstract Recycle of material or energy can change the effective dynamic behavior of a process. Distillation towers are inherently recycle processes. Published tower time constants based on linear analysis have been substantially in error when compared to actual responses for many cases. The reason for this error is shown to be the recycle nature of distillation towers. An improved method of estimating time constants, which can be extended to industrial towers, is presented.