Mixing effects in stirred tank reactors: a comparison of models

Abstract The Two-Environment Model of Ng and Rippin and the Monte Carlo residual life time model of Kattan and Adler developed for studying the effect of arbitrary residence time distribution and intermediate degrees of segregation on chemical reactor performance were shown to be equivalent from the point of view of a physical argument and a comparison of conversions obtained for a second order chemical reaction with mixed feed. Conversions with mixed feed were compared for a single CSTR and a reactor with a 2-CSTR residence time distribution using identical values of the micro-mixing parameter for both of the models. The Monte Carlo Coalescnece Model of Spielman and Levenspiel, Macro-mixed feed model of Manning and the Two-Environment Model of Ng and Rippin were found to give nearly identical results for (1) a single second order reaction, (2) consecutive second order reactions, and (3) step-wise addition polymerization without termination taking place in a single CSTR with mixed feed. Identical values of the micro-mixing parameter for the respective models were used. The models of Manning , Ng and Rippin, and Villermaux and Zoulalian were extended to reactors with unmixed feed with special reference to a second order chemical reaction. Results calculated from these models were compared with those from the models of Spielman and Levenspiel and Kattan and Adler using identical values of the micro-mixing parameter. The models do not agree for unmixed feed.