000			02149nab a2200205 4500
005			20260520002824.0
008			260224s2009 xxu
245	0	0	_aRelation betweenn nanoscale structure of asphaltene aggregates and their macroscopic solution properties
260			_a _b _csep./oct. 2009
270			_a17/06/2010 ; 17/06/2010
300			_a12 p. ; 617-628
520			_aTranscripción del resumen del autor. Some peculiar macroscopic properties of crude oils are ascribed to their densest, heaviest and most polar fraction: the asphaltenes. The comprehension of the origin of these properties relies on a fine structural description of these fractions. We present a nanometre length scale characterisation of asphaltene solutions based on new or recent scattering experiments (X-rays and neutrons) from which structural parameters of asphaltene aggregates (Mw, Rg and A2) are extracted. The mutual dependence of these parameters is consistent with a mass fractal model. This single model accounts for very different macroscopic solution properties. Solvent trapping in fractal aggregates enables asphaltene solution viscosity to be fully predicted as a function of asphaltene concentration. Asphaltene adsorbs at liquid-liquid and liquid-solid interfaces as a monolayer whose thickness is of the same order of magnitude as the characteristic size of the asphaltene aggregate in bulk. Adsorption isotherm analysis, neutron reflectivity experiments and contrast-matching SANS allow one to highlight a densification of the asphaltene aggregates in the adsorbed layer in comparison with the solvated aggregates in bulk. Finally, the repulsive/attractive interaction balance between aggregates can be related to the relative stability of water in oil emulsions and to the stability of hydro-conversion effluents. This structure/property approach allows one to assess the mass fractal model which is discussed.
581			_a5
773	0		_tOil and Gas Science and Technology _g64
942			_cARTICULO
100	1		_aBarré, L. _912689
100	1		_aJestin, J. _942998
100	1		_aMorisset, A. _942999
999			_c171200 _d171200