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Experimental investigation of rheological and morphological properties of water in crude oil emulsions stabilized by a lipophilic surfactant

Sadeghi, M. B ; Sharif University of Technology | 2013

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  1. Type of Document: Article
  2. DOI: 10.1080/01932691.2012.667297
  3. Publisher: 2013
  4. Abstract:
  5. Rheological behavior of two crude oils and their surfactant-stabilized emulsions with initial droplet sizes ranging from 0.5 to 75 μm were investigated at various temperatures under steady and dynamic shear testing conditions. In order to evaluate the morphology and Stability of emulsions, microscopic analysis was carried out over three months and average diameter and size distribution of dispersed droplets were determined. The water content and surfactant concentration ranged from 10 to 60% vol/vol and 0.1 to 10% wt/vol, respectively. The results indicated that the rheological properties and the physical structure and stability of emulsions were significantly influenced by the water content and surfactant concentration. The crude oils behaved as Newtonian fluids over a wide range of shear rates, whereas the emulsions behaved as non-Newtonian fluids, indicating shear-thinning effects over the entire range of shear rates. The viscosity, storage modulus and degree of elasticity were found to be significantly increased with the increase in water content and surfactant concentration. The maximum viscosity was observed at the point close to the phase inversion point where the emulsion system changes from water-in-oil emulsion to oil-in-water emulsion. The results also indicated that the rheological properties of crude oils and their emulsions are significantly temperature-dependent
  6. Keywords:
  7. Droplet size ; Rheological behavior ; Surfactant ; Water-in-crude oil emulsion ; Average diameter ; Dispersed droplets ; Droplet sizes ; Dynamic shears ; Emulsion systems ; Experimental investigations ; Increase in water content ; Lipophilic surfactants ; Microscopic analysis ; Newtonian fluids ; Non-Newtonian fluids ; Oil-in-water emulsions ; Phase inversion ; Physical structures ; Rheological and morphological properties ; Rheological behaviors ; Rheological property ; Shear-thinning effects ; Surfactant concentrations ; Surfactant-stabilized ; Temperature dependent ; Water in oil emulsions ; Crude oil ; Drops ; Elasticity ; Emulsification ; Non Newtonian liquids ; Rheology ; Shear deformation ; Surface active agents ; Viscosity ; Emulsions
  8. Source: Journal of Dispersion Science and Technology ; Volume 34, Issue 3 , Feb , 2013 , Pages 356-368 ; 01932691 (ISSN)
  9. URL: http://www.tandfonline.com/doi/abs/10.1080/01932691.2012.667297