The dynamic behavior of a gas—liquid chromatographic column was investigated to develop methods for estimation of the pulse response and dead time. A mathematical model describing the column behavior was proposed and the resulting response curves compared with the experimental column behavior. This study indicated that the models based on assumptions of perfect mixing and plug flow could be used to predict the dead time which could represent the residence time of the solute gas through the column if enough subdivisions were used for the simulation. Van Deemter's model was verified experimentally and adequately describes the gas—liquid chromatographic column in process control computer simulation of the system. The values of the system parameters characterizing the dynamic behavior were obtained from the simulation. The pulse response curve simulation is unique for the estimation of dead time just as is the transient response curve for the steady-state time.
Read full abstract