Paper Number
EF8 

Session
Emulsions, Foams & Interfacial Rheology

Title
Coalescence inhibition through asphaltene adsorption

Presentation Date and Time
February 13, 2017 (Monday) 2:20

Track / Room
Track 4 / Sandhill Crane

Authors (Click on name to view author profile)

1. Bochner de Araujo, Simone (Stanford University, Chemical Engineering)
2. Merola, Maria C. (Stanford University, Chemical Engineering)
3. Vlassopoulos, Dimitris (Foundation for Research and Technology - FORTH, Institute of the Electronic Structure and Laser)
4. Fuller, Gerald G. (Stanford University, Department of Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Simone Bochner de Araujo¹, Maria C. Merola¹, Dimitris Vlassopoulos², and Gerald G. Fuller^1
1Chemical Engineering, Stanford University, Stanford, CA 94305; ²Institute of the Electronic Structure and Laser, Foundation for Research and Technology - FORTH, Heraklion, Crete 70013, Greece

Speaker / Presenter 
Bochner de Araujo, Simone

Text of Abstract
Asphaltenes are complex polar components of heavy oils and are only marginally stable in organic solvents. Because of this marginal solubility, they have a propensity to adsorb onto oil/water interfaces to form viscoelastic layers. This can result in a strong stabilization of water-in-oil emulsions that cause difficulties in refining operations. In this work we examine the coalescence process of both water and oil droplets against an oil/water interface in the presence of asphaltenes using a newly developed instrument where the thickness of thin, draining films can be measured in space and time. Using this device, thin film thickness, internal droplet pressure and coalescence times can be measured. These results are further compared against measurements of the interfacial shear and dilatational viscoelasticity of asphaltene-laden interfaces. In addition to asphaltene concentration in an aromatic hydrocarbon (toluene), the aging time of the interfaces was varied. Both asphaltene concentration and aging time were found to strongly affect the coalescence dynamics for water droplets. On the contrary, for oil droplets, the asphaltene concentration and the aging time had a weaker effect on the coalescence dynamics. In addition, we found that the contact of water against asphaltene/toluene solutions induced the production of a remarkable emulsification where micron-sized water droplets, stabilized by asphaltenes, spontaneously appeared.