A study of micromixing in tee mixers

Abstract

Micromixing in the three side tees and two opposed tees made of Lucite was studied by means of the consecutive competitive azo coupling reactions first proposed by Bourne and co-workers (1981). Conversion and selectivity were measured in experiments where linear velocities, velocity ratio, and the viscosity of the larger stream were varied, the nonviscous smaller stream being always in turbulent flow. The velocity ratio which resulted in the best micromixing was determined for the side tees, and an empirical relationship was developed between this ratio and the diameter ratio, d/D. Results with opposed tees seem to suggest that the same relationship may also hold for the opposed tees. An overall mixing index, $ = XB(1 -Xs), had to be defined for quantifying the intensity of mixing, and plots were made of $> at optimal velocity ratio vs. the Reynolds number of the larger stream. For both types of tees, it was found that $ increased to a Reynolds number of 104 and remained constant beyond this value with Xs leveling off at about 0.12. Applications to design and practical implications are discussed.

Optimum design of a Tee mixer for fast reactions

“…(1990) 0 Cozewith and Busko(1989) . Tosun (1987) All of the data points, with the exception of two for d / D < 0.1, were found to be correlated with Eq. 6 to within 20% for a value of the constant @ = 1.6.…”

“…In particular, the suitability of pipeline mixing tees for reactor applications, where the reaction times are small, depends on achieving homogeneity of the reactant concentrations in short times. Tosun (1987) studied the product yield of tee mixers with competitive consecutive reactions. The experimental data of Tosun demonstrated a distinct minimum in the undesirable product yield for certain tee mixer geometries.…”

Mixing and the selectivity of fast chemical reactions

“…Some mixers, whose suitability for obtaining high selectivities from fast reactions has been studied, include the centrifugal pump [33], pipeline [34][35][36], rotor-stator mixers of various sizes [37,38], thin liquid sheets [39,40], static mixers [41,42], 'T' junctions [43], free jets [44][45][46], grid turbulence [47], and agitated tanks 23,26,27,29,, as well as a tubular membrane model [S7] and a simple injector in a tube [S8]. In all these cases the energy dissipation rate, c, and hence the mixing rate and other finescale turbulence properties vary significantly from place to place.…”

Membrane‐dispersion reactor in homogeneous liquid process

“…These effects are economically as well as ecologically important. stirred tank, Kenics static, 6 Couette flow, 7 Tee, 8 ultrasound, 9 electro-hydrodynamic (EHD), 10 rotating packed bed, 11 and impinging stream, 12,13 have been devised to intensify mixing. stirred tank, Kenics static, 6 Couette flow, 7 Tee, 8 ultrasound, 9 electro-hydrodynamic (EHD), 10 rotating packed bed, 11 and impinging stream, 12,13 have been devised to intensify mixing.…”

“…5 A variety of reactors, e.g. stirred tank, Kenics static, 6 Couette flow, 7 Tee, 8 ultrasound, 9 electro-hydrodynamic (EHD), 10 rotating packed bed, 11 and impinging stream, 12,13 have been devised to intensify mixing.…”