Abstract
The interaction between a natural Na+-montmorillonite and a crude oil sample containing 2.5 wt % of asphaltene and 6.4 wt % of polar species is studied as a function of time. The microscopic and the macroscopic mechanisms of diffusion are examined and discussed. At a microscopic scale, diffusion of crude oil within the clay interlayer space is a slow and a continuous process with the formation of O/W microemulsions within the d(001) space, which involves those crude oil polar molecules with tensoactive properties, interlayer water molecules, and the clay Na+ interlayer cations. At a macroscopic scale, the diffusion of the organic species is also a slow but stepped process. At the beginning, such a process is controlled by a concentration gradient (the Fick law) of crude oil species which diffuses into clay pellet, and it is followed by a viscous flow-type diffusion, when the compacted clay mineral pellet is surrounded by a thick O/W emulsion of crude oil, clay colloids, and water expulsed from the interlayer space.
Original language | English |
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Pages (from-to) | 1417-1424 |
Number of pages | 8 |
Journal | Energy and Fuels |
Volume | 19 |
Issue number | 4 |
DOIs | |
State | Published - Jul 2005 |
Externally published | Yes |