High‐Pressure Homogenization as a Process for Emulsion Formation

Abstract

Emulsions find a wide range of application in industry and daily life. In the pharmaceutical industry lipophilic active ingredients are often formulated in the disperse phase of oil-in-water emulsions. Milk, butter, and margarine are examples of emulsions in daily life. In the metal processing industry emulsions are used in the form of coolants. Emulsions can be produced with different systems. In the following, the process of high-pressure homogenization is briefly compared to other common mechanical emulsification systems. To facilitate the selection of an emulsification system, the influence of the most important parameters of the emulsion formulation on the resulting mean droplet diameter in the most prevalent continuous emulsification systems is outlined. Subsequently, the most common high-pressure homogenization systems are discussed in detail. On the basis of data from the literature and own experimental results the described high-pressure homogenization systems will be compared regarding their attainable mean droplet diameter. It shows that homogenizers with a relatively simple geometry like the patented ªcombined orifice valveº (Kombi-Blende) attain the smallest mean droplet diameters. The advantage of the ªcombined orifice valveº compared to other high-pressure homogenization systems is not more efficient droplet disruption but rather more efficient droplet stabilization against coalescence immediately after the droplet breakup. The greatest research potential concerning the development of new high-pressure homogenization systems is still to be seen in improvements of droplet stabilization, i.e., the reduction of coalescence.

Liquid–liquid dispersion in a continuous oscillatory baffled reactor – Application to suspension polymerization

“…It has to be stable enough to prevent from coalescence and destabilization in course of polymerization. Different continuous processes are available to create liquid-liquid dispersion including membrane [13], rotor-stator [14], static mixer [15][16][17], colloid mills [14,18], high pressure homogenizer [19], mixer-settler [20] and pulsed column [21,22]. A remarkable feature of continuous liquid-liquid dispersion processes are their ability to create quickly droplet of controlled size.…”

“…A remarkable feature of continuous liquid-liquid dispersion processes are their ability to create quickly droplet of controlled size. Whereas in batch stirred tank reactors, the emulsification time, defined as the time needed to reach stabilized mean droplets sizes, is typically about 15-30 min [17,[23][24][25][26], this time can be a limiting step when it comes to continuous process owning residence time ranging from microsecond, to millisecond, to second [15][16][17][18][19]. Table 1 provides some examples of mean droplet size correlation including their range of applications depending on the chemical parameters (viscosity, densities, and interfacial tension), equipment parameters (porosity, pore diameter, pipe diameter, stirrer dimension.…”

“…vol. [19] High pressure 0.1-3 ms Optimal range of viscosity 1-200 mPa - Table 2 Liquid-liquid dispersion in batch oscillatory baffled reactor.…”

Interfacial Energy During the Emulsification of Water-in-Heavy Crude Oil Emulsions

“…Comparisons between the energy density for different devices have been discussed in the literature (Walstra and Smulders, 1998;Schubert et al, 2003;Schultz et al, 2004). In general, these authors verified that energy densities between 1 and 100 J/cm 3 are needed to produce O/W emulsions using rotor stator devices.…”

Improving Product Quality with Entrapped Stable Emulsions: From Theory to Industrial Application

“…Increasing the viscosity of the dispersed phase might increase the droplet size [56]. The correlation function between mean droplet diameter (d) and viscosity of dispersed phase (η d ) is [81,82]:…”