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Physical Behavior of Asphaltenes

2007; American Chemical Society; Volume: 21; Issue: 5 Linguagem: Inglês

10.1021/ef060634c

1520-5029

E. B. Sirota, Min Lin,

Enhanced Oil Recovery Techniques

Asphaltenes are molecules which can undergo a thermodynamic liquid−liquid phase separation from sufficiently paraffinic solutions. The asphaltene-rich phase thus formed often has a high glass-transition temperature, and thus a fractal morphology results. Here, we report temperature and time-dependent neutron scattering studies which elucidate the solution behavior of asphaltenes. The temperature−composition dependence of the asphaltene precipitation phase boundary is shown to be consistent with that expected due to solution theory. We report temperature- and concentration-dependent viscosity data which demonstrate that the high viscosity of asphaltene-containing systems is due to their proximity to the glass transition and the reduction of viscosity with dilution is no more than a plasticization effect, or a reduction of the glass transition with dilution.