Abbas Khaksar Manshad - and Gas Center of Excellence, Department of Chemical Engineering, University of Tehran, Tehran, Iran
Siavash Ashoori - Department of Petroleum Engineering, Petroleum University of Technology, Ahwaz, Iran
Mohsen Edalat - Oil and Gas Center of Excellence, Department of Chemical Engineering, University of Tehran, Tehran, Iran

In this work, a new algorithm for polydisperse asphaltene modeling through application of continuous molecular thermodynamics is introduced. The Scott-Magatt theory of polydisperse is applied at equilibrium condition and a necessary and sufficient condition is defined to minimize the Gibbs free energy relation. Three common used distribution functions have been examined for characterization of asphaltenes and experimental data reported in the literature is used to adjust parameters of the distribution functions. Among the three distribution functions, the fractal molecular weight distribution function which gives accurate results is selected. A new exponential binary interaction coefficient between asphaltene and crude oil is introduced. The solubility parameter, volume fraction of asphaltene and the amount of asphaltenes precipitated are calculated through minimization of Gibbs free energy and phase equilibrium condition. It has been shown that the calculated results are in good agreement with experimental data.

Asphaltene precipitation; Polydisperse; Binary interaction coefficient; Distribution function; continuous thermodynamic