A multivariate screening analysis of w/o emulsions in high external electric fields as studied by means of dielectric time domain spectroscopy .2. Model emulsions stabilized by interfacially active fractions from crude oils

The electrically induced coalescence of water-in-oil emulsions stabilized by interfacially active fractions from crude oils has been studied by means of time domain dielectric spectroscopy at high electric fields. The experiments were designed with a 2(7-3) reduced factorial design, Regression analysis clearly shows that the choice of organic solvent and the amount of asphaltenes, as well as the interplay between these variables, are the most significant parameters for determining the stability of these emulsions. It should be pointed out that the asphaltenes were the only surface active fraction tested, No interplay between, for instance, asphaltenes and resins was investigated, The nonlinearity found in the regression analysis is explained by different aggregation states of asphaltenes in aliphatic and aromatic solvents, The influence of the variables upon the emulsion stability is discussed. (C) 1996 Academic Press, Inc.