Identification of a Binary Distillation Column Using Pulse Testing

Authors: Ş. İsmail KIRBAŞLAR, Ahmet AYDIN, Umur DRAMUR

Abstract: The binary system of methanol-tert-buthanol was studied at atmospheric pressure in a 53-tray, 35 mm inside diameter sieve tray distillation column. The column had a vertical thermosiphon reboiler and an overhead condenser. During the continuous distillation, the effect of the reflux flow rate and vapour flow rate to the column as rectangular pulse input variables were investigated in the frequency domain. The experimental rectangular pulse input x(t) and output y(t) of the column were entered into a Pulse Test Program. The real and imaginary roots, log modulus phase angles and steady state gains (K) were calculated by the program. Then, Bode plots were drawn. The time constants and time delays were calculated from the Bode plots. The open-loop transfer functions of the top and feed plate were derived. The transfer functions and initial parameters of the column were entered into a commercial simulation program. The experimental and simulation results were compared.

Keywords: Distillation column, frequency domain analysis, dynamic behaviour

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