(468e) Correlation for Yield of Competitive Reactions with Turbulent Mixing

A correlation for yields of products of competitive reactions with turbulent mixing resulted in a plot of [yield/perfect yield] versus a mixing Damkoehler number, the ratio of mixing time to reaction time, written as follows: DaM = TauM/TauR, where TauM = 2(L^2/Eps)^1/3 and TauR = 1/(k1 k2 CAf CBres)^1/2. Such competitive reactions are represented by A + B --> R; R + B --> S and A + B --> R; C + B --> S. The scale of mixing L is approximated in a stirred vessel by Df = (4Qf/Pi Ubt)^1/2 and the rate of turbulence energy dissipation rate in a stirred vessel Eps is given by Ni NP D^2 N^3/[(T/D)^3(Pi/4)]. [Symbols are defined as follows: k1 and k2 are rate constants for reactions 1 and 2, CAf and CBres are molar concentrations of the feed A and the resident B, Df is the diameter of the feed jet as stretched or compressed by the flow, Qf is the volumetric feed rate, Ubt is the blade tip speed of an impeller, Ni is the ratio (feed point/average) , NP is the impeller power number, N is the impeller rotation rate, T is the vessel diameter, and D is the impeller diameter.] The same approach also works in many turbulent pipe reactors where the geometry of the feed injection is well known.

A recent more detailed dimensional analysis has shown the need to include the effect of the ratio of reaction rate constants, k2/k1, in the correlation, even though the ratio of yield to perfect yield removes most of the divergence. The new correlation effectively separates experimental data for different k2/k1-ratios. Initial work to extend the correlation method to solid-liquid reactions with turbulent mixing will also be presented.