Mixed stage

Scheibel (Ref. 2) has shown that the efficiency of a mixing stage can be correlated to the power per unit of throughput, and is related to the ratio of dispersed/continuous phase flow rates this is shown in Fig. 15-47. 

FIG. 15-47 Correlation of mixing-stage efficiency with power input and liquid flow rates. [Scheihel in Lo, Baird, Hanson, Handbook of Solvent Extraction, p. 428 John Wiley h- Sons, NY, 1983. Used with peimission.]... 

If die equivalent number of perfectly mixed stages N is not an integer, let i be an integer slightly smaller dian N. A fraction 0 < h < 1 is defined as... 

An Excel spreadsheet (Example8-7.xls) was used to determine the various RTD functions and the computer program PROGS 1 was used to simulate the model response curve with the experimental data. The results show the equivalent number of ideally mixed stages (nCSTRs) for the RTD is 13.2. The Gamma distribution function from Equation 8-143 is ... 

The two models commonly used for the analysis of processes in which axial mixing is of importance are (1) the series of perfectly mixed stages and (2) the axial-dispersion model. The latter, which will be used in the following, is based on the assumption that a diffusion process in the flow direction is superimposed upon the net flow. This model has been widely used for the analysis of single-phase flow systems, and its use for a continuous phase in a two-phase system appears justified. For a dispersed phase (for example, a bubble phase) in a two-phase system, as discussed by Miyauchi and Vermeulen, the model is applicable if all of the dispersed phase at a given level in a column is at the same concentration. Such will be the case if the bubbles coalesce and break up rapidly. However, the model is probably a useful approximation even if this condition is not fulfilled. It is assumed in the following that the model is applicable for a continuous as well as for a dispersed phase in gas-liquid-particle operations. 

Fig. 4. Number of perfectly mixed stages-for gas flow in a bubble-column as a function of bed height L and superficial gas velocity u, [Kolbel et al. (K17)].

KUger Y, GaUo SA, Peisajovich SG, Munoz-Barroso 1, Avkin S, Blumenthal R, Shai Y (2001) Mode of action of an antiviral peptide from HlV-1. Inhibition at a post-lipid mixing stage. J Biol Chem 276 1391-1397... 

Reactor type Fork-like chip micro mixer-tube reactor Characteristic structure of the mixing stage G structure ... 

Number of mixing stages within one mixing channel 6 3 in top plate, 3 in bottom plate Tube length Not reported... 

Number of plates needed to form mini mixer channel 2 Number of mixing stages 8... 

Figure 3.44. The well-mixed stage representation of a mixer-settler unit.

Owing to the intensive agitation conditions and intimate phase dispersion, obtained within the mixing compartment, the mixer can usually be modelled as a single, perfectly mixed stage in which the rate of mass transfer is sufficient to attain equilibrium. As derived previously in Sec. 3.3.1.3, the component balance equations for the mixer, based on the two combined liquid phases, is thus given by... 

Considering the end regions of the column as well-mixed stages, with small but finite rates of mass transfer, component balance equations can be derived for end stage 0... 

Materials used to protect vulcanisates from deterioration, including surface coatings as well as the ingredients added to the rubber at the mixing stage. See Antioxidant, Antiozonant, Paraffin Wax. 

Oil extended SBR, and SBR carbon black masterbatches are supplied by the polymer producers and such grades give the advantage of reducing the necessity of further additions of filler and oil at the mixing stage. 

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