A THERMODYNAMIC MIXED-SOLID ASPHALTENE PRECIPITATION MODEL

A simple model for the prediction of asphaltene precipitation is propo sed. The model is based on an equation of state and uses standard ther modynamics, thus assuming that the precipitation phenomenon is a rever sible process. The solid phase is treated as an ideal multicomponent m ixture. An activity coefficient model based on the athermal Flory-Hugg ins expression was included to account for solid phase non-ideality, b ut was found to have little effect on the results. Only a fraction of each of the heaviest components are considered potentially solid formi ng. This approach is based on the assumption, that out of the total PN A composition of a crude, the asphaltenes and resins are mainly aromat ic-naphtenic in their nature. The predictions shows the correct qualit ative behavior with respect to temperature and pressure, but due to la ck of data the model was not evaluated quantitatively with respect to these effects.