Estabilidade de emulsões de água-em-óleo sob ações eletrocisalhantes e campos elétrico e centrífugo

Abstract

Twenty model emulsions and two water-in-oil crude oil emulsions were produced. In model emulsions, the adsorption of surfactants chosen is spontaneous and the area occupied by molecules on interface is a function of the formal charges presence (or absence) on polar head and the hysterical impediment caused by the structure of each molecule. There was also a correlation between emulsions droplet size and elastic moduli with systems’ stability in different applied techniques. For the experiments under electric field, the electrocoalescence cell was improved and validated using the electro-rheology technique. When applying electric field during a rheological test, besides de CEF, model emulsions present a minimum electric field to overcome drops’ Brownian motion barrier and to produce the alignment between electrodes. Such minimum field is directly related to both the stabilizer amount used to produce the emulsion and the critical electric field. For crude oil emulsions, the electrostatic breakage occurs in a unique way for each different crude oil used as a continuous phase.