Identification of a binary distillation column

In this paper the identification of a binary distillation column simulated in a digital computer is described. The pseudo-random binary signal method has been used to disturb two inputs of the column. The well-known cross-correlation technique was used to compute the impulse response matrix G(s), and with a non-linear programming technique a parametric model has been obtained. These results were discretized in order to get a digital transfer matrix, and a discrete state space model suitable for digital control purposes was derived. The reduced-order linear model obtained was compared with the complete non-linear model of the distillation column. Problems involved with correction of the reduced model for any operating conditions are examined and a model-correction algorithm is suggested.