A new thermodynamic model for the prediction of asphaltene precipitation in crude oil

Abstract

It has been proved that asphaltene precipitation is a difficult problem to define and study. Precipitation of these complex and heavy organic compounds can cause serious problems in crude oil production and transportation, residual oil processing and heavy oil combustion. Several theories have been proposed to explain the mechanism of asphaltenes precipitation. The Flory-Huggins (F-H) is one of the famous models, which are used to describe the asphaltene precipitation mechanisms in the same ways as polymeric solutions. In this research, the F-H model has been modified to predict the phasebehavior of asphaltene precipitation process during adding non-polar (normal alkane) solvents. The adjustable parameters of this model are computed by using a least-square approach between the modeling results and experimental data. Then, the results of these models are compared with the obtained results of the original F-H and the experimental data at different conditions. According to the interaction parameter as an adjustable parameter, four new functionalities have been used for this target. According to the obtained results, the modified model with a second order equation can predict the amount of asphaltene precipitation better than the others with a minimum error. The calculation shows good agreement between theexperimental data and the results of the modified model.

Keywords

• asphaltene
• precipitation
• solvent
• modeling
• crude oil