Experimental verification of a model describing the transient behaviour of a reaction system approaching a limit cycle or a runaway in a CSTR

Abstract

In a continuous flow stirred tank reactor (CSTR) the temperature of a reaction system - the acid-catalysed hydration of 2,3-epoxy-1-propanol to glycerol - has experimentally been determined as a function of time for the approach of a limit cycle and a runaway. For the complete description of the behaviour of this reaction system in a CSTR, use is made of a model consisting of the unsteady-state mass and energy balances and the reaction-rate equation. This model contains the variables temperature, concentration and time and fourteen other relevant physical quantities. These physical quantities - indicated by α j - were assumed to be both constant and subject to error. The measured values α j,m of these physical quantities were determined separately. The best-fit values α j,fit were obtained with a least-square method using 89 temperature values sequentially measured every five seconds during two oscillation periods. The present model has been verified by showing that : - substitution of the values of α j,fit in the model results in an excellent description of the measured temperature oscillations mentioned; - for each of the fourteen physical quantities α j, the difference α j,m − α j,fit is smaller than the possible deviation in α j,m. Moreover, a runaway encountered in the course of our experiments and caused by an improper start-up procedure will be treated.