Modeling and Prediction of Asphaltene Adsorption Isotherms Using Polanyi's Modified Theory

The deposition of asphaltenes is one of the most difficult problems to overcome in crude oil production and processing. The presence of asphaltenes in crude oil and, consequently, the adsorption and deposition of asphaltenes on rock surfaces, affects rock properties such as porosity, permeability, and wettability. In this study, a novel model for modeling and predicting adsorption isotherms of asphaltenes based on Polany's modified theory is proposed. This approach enables prediction of adsorption isotherms at different temperatures (usually corresponding to reservoir temperatures), thereby improving our understanding of adsorption equilibrium behavior at reservoir conditions, which should lead to reductions in experimental/analytical time and operation costs. The theoretical predictions of isotherms were validated successfully by determining the root-mean-square errors (RSM%) between data obtained from published literature and values predicted for asphaltenes and surfaces with differing chemical natures. The RSM% value is below 5% for all predictions. Additionally, the Dubinin-Astakhov model is used to correlate adsorption characteristic curves, resulting in RSM% values lower than 10%.