Premix droplet size distribution

Altenbach-Rehm, J., Suzuki, K., and Schubert H., Production of O/W-Emulsions with Narrow Droplet Size Distribution by Repeated Premix Membrane Emulsification, Proceedings of the third World Congress on Emulsions, Lyon, France, September 24-27, 2002, 6 pp. 

In premix membrane emulsification, emulsion premixes are pressed through the membrane pores. A phase inversion while passing the membrane is induced if the membrane surface is wetted by the droplet phase of the premix. Thus emulsions of high disperse phase fractions, even above 80%, can be produced at a throughput of up to several tons per square meter of membrane surface per hour. A narrow droplet size distribution requires a low number (2-3) of recirculations through the membrane. The mean droplet size is about twice the pore size [51]. 

Figure 13.9 Droplet size distributions in premix membrane emulsification at different transmembrane pressure differences.

Altenbach-Rehm J, Suzuki K, Schubert H. 2002b. Production of OAV-emulsions with narrow droplet size distribution by repeated premix membrane emulsification. In Proceedings of the 3rd World Congress on Emulsions. Lyon. 

Figure 21-5 (a) Premix burner. (fc>) End view of flame. The slot in the burner head is about 0.5 mm wide, (c) Distribution of droplet sizes produced by a particular nebulizer. 

Figure 13.9 gives an example of droplet volume density distributions of emulsions obtained by pressing an emulsion premix through a membrane at transmembrane pressure differences varying from 3 bar to 11 bar. These pressure differences are 7.5- to 27.5-fold the minimum pressure difference required (capillary pressure). A hydrophilic polyamide membrane with a mean pore size of 0.8 pm was used. The emulsion premix consisted of 20% dispersed phase (vegetable oil). As continuous phase water containing emulsifier Tween 80 at a concentration of 2% was used. The Sauter diameter of the emulsion premix was X3,2 = 25 pm. 

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