Breakup Characteristics of Water-in-Oil Emulsion Droplets Influenced by a Rigid Interfacial Film in the Presence of a Polymer Surfactant

The emulsified feedstock technique derived frommicro-explosion has been applied to improve the feedstock atom-ization of heavy oil during the catalytic cracking process. The strengthof an interfacialfilm, which is vital for the stability of emulsion, can beenhanced by some polymer surfactants. In this study,n-hexadecanewas chosen as the model oil. The effect of oil-water interfacialfilmproperties on the high-temperature breakup of emulsified droplets wasinvestigated, especially the interfacialfilm strength of water-in-oil (W/O) emulsion in the presence of a commonly used non-ionic surfactantand/or polymer surfactant (Arlacel-P135). The mean diameter ofdispersed water and interfacial tension and interfacialfilm strength ofemulsions were measured. Afterward, two breakup modes of emulsifieddroplets were revealed by the single droplet heating test, which are"micro-explosion"and"breakup after bubble expansion". Theemulsified droplet stabilized by Arlacel-P135 is more prone to"breakup after bubble expansion"for the rigid oil-water interfacialfilm hindering the coalescence of dispersed water. The stability and oil-water interfacial strength of emulsions stabilized by mixedsurfactants consisting of Span80, Tween80, and Arlacel-P135 were enhanced with the increase in Arlacel-P135 dosage. Moreover,the addition of Arlacel-P135 (0.2-0.5 wt %) significantly reduced the average breakup delay time (Tau) of W/O droplets, since thebubble nucleation was favored by the interfacialfilm structure formed by polymer surfactant.