Mechanical mixing homogeneous initial conditions

We have presented here a non-trivial case study of a chemical reactor where fluid mechanics, diffusion, and chemical reaction are treated at the same level of complexity. The results indicate that conversions and product distributions can be significantly modified by mixing effects, for operating conditions of interest considerable error can be introduced by assuming homogeneous initial conditions. 

Figure 4.13. Predictions of the SR model for ReA = 90 and Sc = 1 for homogeneous scalar mixing with = 0. For these initial conditions, all scalar energy is in the dissipative range. Curves 1-3 and D correspond to the fraction of scalar energy in each wavenumber band

The method of suspension receipt by mixing of initial homogeneous reagents in turbulent regime realized by rotary pumps arms is prevalent at conditions of industrial production for carrying out of fast chemical reactions. With the aim of comparison of effectiveness of work of tubular turbulent apparatus and tank reactors (rotary pumps) mechanical mixer of "turnip" type was chosen that woriced by rotary pump principle. In combination with intensive circulating movement in vertical direction (Fig. 5.18) high speed at mixer s end leads I... 

Noteworthy features of this method are that nonhydrated oxides without residual hydroxo groups are obtained, due to the aprotic conditions, and that in bimetallic systems the metals M and M have an alternate order (no phase separation), due to the reaction mechanism (Eq. (1.7)). A limitation of nonhydrolytic processes is that the M/M ratio is not freely selectable if fully condensed products are targeted. Eor this reason, sol-gel processes of mixed metal systems are sometimes initiated by nonhydrolytic reactions (to obtain a high homogeneity) and then completed by hydrolytic reactions (to obtain complete hydrolysis and condensation). 

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