The effect of imperfect mixing on an idealized kinetic fermentation model

Abstract

Mixing patterns in stirred reactors are analyzed in this study from the point of view of the hysteresis behavior of final product rate as a function of the intermediate concentration in the sequential reaction A → B → C. A two-tank system model with an internal recycle stream is studied, in order to simulate the effect of imperfect mixing in a single batch reactor. The extent of mixing between positions at which product and intermediate species concentrations are measured in the reactor is revealed in both the direction of the hysteresis function and the relative magnitude of the inscribed area. Another approach, which apparently simplifies the analysis, is to measure the concentration of B in each of the two tanks and cross-plot the two variables. This latter technique not only avoids the errors resulting from differencing the data, but also leads to correlations between the circumscribed areas and the degree of mixing.