STUDIES OF TRANSPORT OF ASPHALTENES THROUGH MEMBRANES USING HINDERED DIFFUSION THEORIES FOR SPHERES AND SPHEROIDS

The results of ongoing efforts by this group to model the transport of asphaltene molecules through model membranes are presented. A model i s described which aims to capture the effect of the polydisperse natur e of asphaltene molecules on their transport properties. The asphalten e structure is generated stochastically using Monte Carlo techniques. Individual asphaltene molecules are approximated as spheroids for the purpose of calculating their hindered diffusivities. Continuum hydrody namic theories and boundary element methods are used to calculate the diffusion coefficients. A number of analytical expressions, scaling re lationships, and approximations utilized in the literature are evaluat ed.