Abstract

VELAZQUEZ-CAMILO, O.; ALVAREZ-RAMIREZ, J. J.  and  BOLANOS-REYNOSO, E.. Comparative analysis of the crystallizer dynamics type continuous stirred tank: Isothermic and cooling case. Rev. Mex. Ing. Quím [online]. 2009, vol.8, n.1, pp.127-133. ISSN 1665-2738.

In this work an operation alternative and controllability was studied by simulation of a stirred tank continuous isothermic crystallizer through of its dynamic characterization. The process model is based on the moments technique. The methodological process consisted on the implementation of a SISO (single input-single output) feedback servocontrol algorithm and a PID (proportional-integral-derivative) controller. The tuning was carried out with the strategies of internal model control (IMC). The process variable to control was the average diameter in % volume D(4,3) = μ₄ / μ₃, because is a useful variable in both commercial and industrial environment; the manipulate variable in isothermic operation and for cooling was the solute concentration in the feeder and cooling temperature, respectively. Since static analysis were obtained zones where the presence of limits cycle exists and values of more favorable residence times to operate and control the crystallization process for isothermic and cooling operation. Feedback PID controller in the two operations was satisfactory eliminating the deviations between the adjustment point and the response of the controllable variable.

Keywords : isothermic crystallization; cooling crystallization; moment's model; dynamic characterization; control strategy.