(422d) Characterization of Mixing in Chemical Reactors with Mean Age and Higher Moments

Liu, M., DuPont Engineering Technology

In this talk, a new theory for characterizing mixing processes in chemical reactors will be discussed. This theory is based on the conservation equations of mean age and higher moments of age in a reactor. These equations are in the same form as N-S equations and can all be solved with the same CFD solvers that are used to solve for the velocity solutions. For a steady continuous flow system, these equations can be solved after the velocity field is obtained. Compare to the current methods of computing residence time distributions by solving time dependent scalar concentration equation or by tracking particles, this new method is not only extremely efficient in using computing resources but also much more accurate in solving for the moments of age inside the reactor and the moments of residence time at the exit. Several examples of steady continuous reactors will be discussed to demonstrate how this new theory can be used to quantitatively characterize mixing performance.