Static mixers mixing rate

Figure 2. Shear stress as a fimction of shear rate at 350 C Coiiq)arison of twin-screw and static mixer mixed PAI-2/LCP blends.

Fig. 31. Comparison of mixing rates with different static mixers A, Lightnin B, Komax C, Etoflo HV D, Kenics E, SMXL E, Hi-Mixer and G, SMX.

Static mixing of immiscible Hquids can provide exceUent enhancement of the interphase area for increasing mass-transfer rate. The drop size distribution is relatively narrow compared to agitated tanks. Three forces are known to influence the formation of drops in a static mixer shear stress, surface tension, and viscous stress in the dispersed phase. Dimensional analysis shows that the drop size of the dispersed phase is controUed by the Weber number. The average drop size, in a Kenics mixer is a function of Weber number We = df /a, and the ratio of dispersed to continuous-phase viscosities (Eig. 32). 

Fig. 11 Overall reaction rates obtained with static mixers and carrier materials in comparison to the reaction rate without mixing T = 50°C, pui = 5bar, Vaq = 300mLmin , Forg = 50mLmin , Vpeed = 3.0mLmin" Vh2 = lOOmEmin ...

The final pH adjustment (Figure 6B) takes place in the feed system to the extraction (WE-1) column. Preneutralized solution in Tank WM-1 is recirculated to provide mixing. Part of the recirculated solution is diverted to the WM-2 static mixer tank where it is mixed with NaOH the volume of NaOH added is controlled by the pH of the WM-2 tank outlet stream. Most of the solution leaving the WM-2 tank is returned to the WM-1 tank the remaining portion feeds the WE-1 Column. The flowrate of this latter stream is adjusted to maintain the liquid level in the WM-1 tank approximately constant. When functioning satisfactorily, the two-stage acid adjustment procedure provides an aqueous E1F stream at pH 0.75 flowing at a constant rate to the extraction column. 

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