Génération mécanique des émulsions

Abstract

Résumé -Les émulsions sont des systèmes complexes très fréquemment rencontrés dans notre vie quotidienne et dans la plupart des secteurs industriels, dont l'industrie pétrolière. La compréhension des mécanismes de formation des émulsions est essentielle pour assurer la maîtrise de leur fabrication ou de leur traitement. Cet article fait une synthèse des principaux phénomènes qui entrent en jeu lors de la formation d'une émulsion. La rupture des gouttelettes en écoulement laminaire ou turbulent est discutée et des corrélations permettant de prédire le diamètre des gouttelettes formées sont données. On présente également le rôle des tensioactifs ainsi que les échelles de temps caractéristiques des différents processus impliqués. Le cas des émulsions pétrolières obtenues en production est étudié plus particulièrement. Keywords: emulsions, formation, emulsification, droplet size, deformation, breaking, shear, turbulence, crude oil emulsions. Oil & Gas Science and Technology -Rev. IFP, Vol. 55 (2000)

A Novel Synthesis of Chitosan Nanoparticles in Reverse Emulsion

“…This can be explained by the Gibbs-Marangoni effect, which is a mass transfer due to the interfacial tension difference. This movement of surfactant works as a self-stabilizing mechanism for the emulsion and is responsible for preventing coalescence …”

Role of Electrical Submerged Pumps in Enabling Asphaltene-Stabilized Emulsions

“…However, the drop size can be correlated to mixing intensity and mixing time. To evaluate the droplet size of produced emulsion, it is possible to employ the following equation, − which assumes that the flow regime is turbulent-viscous (i.e., interfacial stresses are balanced by the viscous stresses). In this regime, breakup of droplets occurs under shear stresses across the continuous medium. The meaning of symbols, together with adopted values, is in Table ; with these values, the resulting maximum droplet diameter is 9 × 10 –6 m.…”

Thermotropic overheating protection glazings: effect of functional additives and processing conditions on the overheating protection performance

“…During the manufacturing process, the uncured matrix material (i.e., a mixture of an oligomer, a reactive diluent and a photoinitiator) and the thermotropic additive form a kind of an emulsion. In conventional emulsions the addition of surfactants yields a reduction in the droplet size by changing the interfacial energy between the continuous and the disperse phase [34][35][36][37]. The addition of surfactants to mixtures of a matrix material and an additive might also reduce the scattering domain size in an analogous way like it was described for conventional emulsions above.…”