Liquid phase dispersion

Fits some, but not all, data. Low mass transfer rate. = mean molecular weight of dispersed phase tf= formation time of drop. k[, i = mean dispersed liquid phase M.T. coefficient kmole/[s - m" (mole fraction)]. 

WiLLE, C., The potential of micromixers for contacting of disperse liquid phases,... 

Haverkamp, V., Ehreeld, W, Gebauer, K., Hessel, V., Lowe, H., Richter, T, WiLLE, C., The potential of micromixers for contacting of disperse liquid phases, Fresenius J. Anal. Chem. 364 (1999) 617-624. 

Figure 8.1b shows a simple gravity settler or decanter for removing a dispersed liquid phase from another liquid phase. The horizontal velocity must be low enough to allow the low-density droplets to rise from the bottom of... 

The amorphous phase is not usually a desirable state for the API because the formation process is more random and difficult to control than a crystallization. A second dispersed liquid phase is usually formed just prior to freezing and may coalesce or disperse under the influence of hydrodynamic forces in the crystallizer, making the process sensitive to micro-mixing effects on scale up. Amorphous solids also have significantly lower thermodynamic stability than related crystalline material and may subsequently crystallize during formulation and storage. Because of the non-uniformity of the amorphous solid it can more easily incorporate molecules other than the API, making purification less effective. 

The addition of a dispersed liquid phase (immiscible organic solvent) changes the rate of transfer of the solute gas across the boundary layer. Physical properties (density, viscosity, gas solubility and gas diffusivity) of the liquid mixture are changed and the gas-liquid characteristics (possible pathway for mass transfer and gas-liquid interfacial area) can be changed owing to the interfacial proper-... 

Jiang, H., Y. Qin, and B. Hu. 2008. Dispersive liquid phase microextraction (DLPME) combined with graphite furnace atomic absorption spectrometry (GFAAS) for determination of trace Co and Ni in environmental water and rice samples. Talanta 74 1160-1165. 

Step 1. First, solve the VCVD ratio, applying Eq. (7.17). Before solving this equation, you must first choose a dispersed liquid phase. Here the solvent having the greatest flow is chosen. You must also determine where the solvent enters the column and which column section you will check. 

A disperse liquid phase and a continuous spray columns... 

In the second part, flow in the vapor space of the separator, where the gas phase is a continuous phase, was modeled. An Eulerian-Lagrangian approach was used to simulate trajectories of the liquid droplets since the volume fraction of the dispersed liquid phase is quite small. The grid used for the vapor space is shown in Fig. 9.20. The simulated gas volume fraction distribution near the gas-liquid interface and corresponding gas flow in the vapor space are shown in Fig. 9.22. The gas volume fraction distribution and the gas velocity obtained from the model of the bottom portion of the loop reactor were used to specify boundary conditions for the vapor space model. In addition to the gas escaping from the gas-liquid interface, it is necessary to estimate the amount of liquid thrown into the vapor space by the vapor bubbles erupting at the... 

Fundamental mixing studies on simple two-component systems have provided insight into the effect of mixing parameters on critical emulsion properties such as particle size distribution. For example, Nagata [81] has shown the distribution of sizes of the dispersed liquid phase as a function of agitator speeds. As we might expect, a normal distribution occurs at higher speeds. In a similar study, the effect of surface tension was determined for several liquid dispersed phases from benzene to paraffin oil [82],... 

Liquid-liquid reactors are similar to gas-liquid reactors. In the former case, the dispersed phase is in the form of droplets as against bubbles in the latter. The motion of bubbles and drops can be described using a unified approach. A spray column (or a drop column) is the equivalent of a bubble column but with one difference. The dispersed gas phase is always lighter than the continuous liquid phase (p < Pl)- However, the dispersed liquid phase in spray columns may be lighter or heavier than the continuous immiscible liquid phase. Nevertheless, spray columns can be easily described similar to bubble columns. Furthermore, packed bubble columns and sectionalized bubble columns can be considered equivalent to packed extraction columns and plate extraction columns. External-loop and internal-loop reactors are also possible (for equivalent gas-liquid reactors, refer to Section 11.4.2.1.4). 

In principal, droplets of a dispersed liquid phase are immersed in a second continuous gas (two-phase gas-liquid) or liquid (two-phase liquid-liquid) phase within a microchannel. Thereby, the inner liquid droplets are separated by the continuous carrier liquid along the channel. If the size of the iimer phase exceeds the cross sectional dimensions of the channel, the droplets are squeezed to form non-spherical segments, also called plugs . Following this flow scheme, the platform is called segmented flow microfluidics. 

Figure 33 shows the apparent viscosity variation with shear rate for 44 fim glass beads suspended in a 50% bitumen-in-water emulsion at 25 °C. The viscosity ratio of the dispersed liquid phase (bitumen) to the... 

Ap = absolute value of the difference in density between the liquids a= interfacial tension between the liquid phases D - fractional holdup in the tank of the dispersed liquid phase pM= two-phase mixture density, given by... 

There are no effective interfacial area correlations in the literature for the specific cases discussed here. The correlation that conies closest to that required for trickle bed operation is that of Puranik and Vogelpohl [29], which is for a continuous gas phase and a dispersed liquid phase, but in a countercurrent packed column, well below the loading point. They derived the following correlation (for piLfQ, = 1.5 kg/m s) ... 

Liquid-liquid mass transfer depends on whether the transfer is from the continuous to the dispersed phase or vice versa. The liquid-liquid interfacial area an can be estimated from an = 6/iL/do where /il is the dispersed liquid phase holdup and c/q is the average size of the dispersed droplets which can be determined from a correlation given by Okufi et al. (1990). 

Concentration of i in continuous liquid phase, mol/m. Concentration of i in dispersed liquid phase, mol/m. ... 

Size of dispersed liquid phase is given in Section 5.3. Horizontal cylindrical vessel with allowance for 20 min residence time for the water phase. Keep liquid velocity < 10 L/s m. Carefully size the inlet distributor for the liquid so that inlet velocity is < 0.4 m/s. 

V. Haverkamp, et al. The Potential of Micromixers for Contacting of Disperse Liquid Phases, Fresenius J. Anal. Chem., 1999, 364, 617-624. 

J. Simple gravity settling tank. In Fig. 14.3-5a a simple gravity settler is shown for removing by settling a dispersed liquid phase from another phase. The velocity horizontally to the right must be slow enough to allow time for the smallest droplets to rise from the bottom to the interface or from the top down to the interface and coalesce. 

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