Kenics static mixers

Fig. 30. Mechanism for laminar blending in Kenics static mixer (a) after one element, (b) two elements, (c) three elements, (d) four elements, and (e) five...

A practical method of predicting the molecular behavior within the flow system involves the RTD. A common experiment to test nonuniformities is the stimulus response experiment. A typical stimulus is a step-change in the concentration of some tracer material. The step-response is an instantaneous jump of a concentration to some new value, which is then maintained for an indefinite period. The tracer should be detectable and must not change or decompose as it passes through the mixer. Studies have shown that the flow characteristics of static mixers approach those of an ideal plug flow system. Figures 8-41 and 8-42, respectively, indicate the exit residence time distributions of the Kenics static mixer in comparison with other flow systems. 

The Kenics STATIC MIXER unit is a series of fixed, helical elements enclosed within a tubular housing. The fixed geometric design of the unit produces the following unique patterns of flow division and radial mixing simultaneously. 

Another comparison is due to Van Wageningen et al. (2004) who performed a similar study (in terms of the numerical scheme used) on unsteady laminar flow in a Kenics static mixer. They found that the LB code was 500-600 times faster than FLUENT in terms of simulation time per grid node per time step and that FLUENT used about 5 times more memory than LB. 

Figure 3.25 Schematic diagram of a Kenics static mixer.

Fig. 7.43 The evolution of concentration distribution after 4, 10, and 20 elements with alternately left and right twisting plates at 140°. [Reprinted by permission from O. S. Galaktionov, P. D. Anderson, G. W. M. Peters, and H. E. H. Meijer, Morphology Development in Kenics Static Mixers (Application of the Extended Mapping Method), Can. J. Chem. Eng., 80, 604-613 (2002).]...

Some units can be adapted for solid-solid blending. The residence time in the units can be varied or adjusted, which makes them suitable for certain types of reactions. Figure 7-18 shows a cross-section of a flanged Kenics static mixer with four helical mixing elements, and Table 7-9 lists the characteristics of static mixers. 

Figure 7-18. Cross-section of flanged Kenics Static Mixer with four helical mixing elements. (Source Chemineer-Liquid-Agitation.)...

Bakker, A. and La Roche, R., Flow and mixing with kenics static mixers, Cray Channels, 15, 3, Cray Research Inc., Eagan, MN, pp. 25-28, 1993. 

RELATIVE COEFFICIENT OF VARIATION FOR KENICS STATIC MIXERS... 

Kenics Bulletin, Kenics static mixers KETK series, May 1988. 

Chemineer. Kenics Static Mixers XTEK Series, Tech. Rep. K-TEK-4. Chemineer, 1988. 

The twisted-element mixers, such as the Kenics static mixer (Fig. 18-61), create 2 layers in n divisions. Each element twists the flow, moving material from the center to the wall and from the wall to the center. The twisting also stretches striations having different properties and reorients the material before the next division. The following element... 

For a thorough discussion, see May 1988 bulletin for Kenics Static Mixers KTEK Series. 

Hobbs D.M., Muzzio F.J., The Kenics static mixer, a three-dimensional chaotic flow, Chem. Engng. J. Laus. 67 (1997) 3, p. 153-166... 

Kenics Static Mixers Marketing through Chemineer Ltd, 7 Cranmer Road, West Meadows Derby DE21 6XT, GB... 

Ling F.H., Zhang X., A Numerical study on mixing in the Kenics static mixer, Chem. Eng. Commun. 136 (199S), p. 119-141... 

Chemineer Inc., Kenics Static Mixers, KTEK Series, May 1988, Chemineer, Dayton, OH, 32 pages. 

FIGURE 9.40 (a) Chemineer Kenics static mixers, (b) Sulzer or Koch static mixers, (c) Ross static mixers, (d) Ross ISG static mixer. (From Ross Systems and Controls.)... 

For the tube reactor only 27% conversion was achieved [34]. A fast flow rate was required due to phase separation and thus, at Re > 2000, about 2 km of tube is needed to have a 5 min residence time, which is impractical. With five Kenics static mixers connected in series a conversion of 97% is achieved. In the microreactor. 

Sununu [173] and Genetti and Priebe [174] used Kenics static mixers for heating of viscous oils (Figs. 11.26 and 11.28, curves e and f). These mixers consist of 360° segments of twisted tapes every second element is inverted and the segments are tack-welded together. The... 

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