(113c) Progress Towards a SAFT Based Crude Oil Fouling Model

A major mechanism of crude oil fouling is asphaltene precipitation. Numerous threshold fouling models have been proposed that require regression to measured data to be applied. These models have utility when working with historical data and users wish to fit models to extrapolate trends into the future for optimization of cleaning and maintenance. By their empirical nature, these models do not explain the underlying mechanism based on the chemistry and thermodynamics of the crude oil constituents. To gain a more fundamental understanding of asphaltene precipitation, HTRI and ENNOVA collaborated to develop a Statistical Associated Fluid Theory (SAFT) model for crude oil that can predict the amount of asphaltenes that precipitate for a given temperature and pressure. The SAFT model is the basis for a crude oil fouling model that assumes the rate of asphaltene precipitation to form primary particles (100-200 nm) is proportional to the degree of super saturation of asphaltenes. primary particles are assumed to cause fouling. primary particles can continue to grow to form larger aggregates that are assumed to not foul. This approach has been successfully applied in upstream context. This theory also explains trends in HTRI fouling data. An overview of the theory, characterization methods, modelling approach and results to date will be provided.