Developing a Mathematical Model of Asphaltene Precipitation Using the Extended Flory-Huggins Theory and the SRK Equation of State

No Persian Abstract

Crude oil components including light and heavy hydrocarbons contained waxes, asphaltene and resins. Changes of operating conditions such as, temperature, pressure and molar content of crude oil in the raw materials led these solids toward precipitating. Asphaltene precipitation considered very common at different stages of well discharge, oil transfer and refining causing an increase in the cost of operation. Given the costly and timely conduct of experiments and the wide range of process variables needed, the most convienient way to predict the asphaltene precipitation considered as thermodynamic modelling of this phenomenon. In this study, through using of the extended Flory-Huggins model in conjunction with the SRK equation of state, the amount of asphaltene precipitation in the presence of two solvents of normal pentane (n-C5) and normal hexane (n-C6) predicted and compared with experimental data available in the open literature. Results revealed the amount of asphaltene precipitation under industrial operating conditions satisfyingly described the available experimental data. In other words, the mean absolute error of 0.15 and 0.14 for n-C5 and n-C6 revealed the strength of the extended Flory-Huggins model.