Emulsion phase inversion of model and crude oil systems detected by near-infrared spectroscopy and principal component analysis

A Model emulsion (water/(heptane-toluene)) phase inversion process induced by changing salt concentration and crude oil emulsions inversion processes induced by alteration of water-oil ratio (catastrophic), temperature and surfactant concentration were monitored by NIR spectroscopy and electrical conductivity. NIR spectra were treated by Principal Component Analysis and the results showed that this technique can be successfully applied to identify emulsion phase inversion, in particular in complex systems such as crude oil emulsions where the collected spectra during the inversion were very similar and in inversion processes with a narrow range of the formulation variable. Furthermore, NIR was also able to detect a dispersion to emulsion transition and plots of the first principal component of NIR spectra and emulsion conductivity provided a much better picture of emulsion inversion than single measurement plots.