Regular solution model to predict the asphaltenes flocculation and sediments formation during hydrocracking of heavy oil

Experiments of hydrocracking of heavy crude oil were carried out in a 1.8 L batch reactor with a mineral dispersed catalyst. Sediments content was analyzed at different reaction times (2-5 h) and temperatures (360-400 degrees C). A regular solution model and a kinetic model were applied to predict the flocculation of asphaltenes to form sediments. It was observed that as the temperature increases the solubility parameter of the SARA fractions decreased. Enhanced sediments formation was found when the saturates/asphaltenes ratio increased indicating that the insolubility of asphaltenes in the crude oil depends on saturates fraction. The calculated values obtained with the thermodynamic-kinetic model showed good accuracy with respect to experimental data, particularly at high conversion, which is the most important issue in commercial hydrocracking units.