Chemical kinetics of SARA fractions pyrolysis: Saturates and aromatics

Abstract

This manuscript focuses on presenting a predictive and widely applicable model for describing the pyrolysis of saturates and aromatics, two of the so called SARA (Saturates, Aromatics, Resins, Asphaltenes) fractions. The fractions extracted from two different oil samples, a typical Heavy Fuel Oil 380 and a typical Vacuum Residue Oil, were thoroughly investigated. Different experimental methods elucidated the elemental composition, chemical structure, thermal degradation behavior, and characterized the products released during the pyrolysis of these two oils. Finally, a model to describe the pyrolysis of saturates and aromatics was developed. The model is comprehensive of methodology for the definition of a surrogate and a kinetic mechanism to describe its pyrolysis. The surrogate is defined using a certain number of pseudo-components, whose mass fraction in the mixture is defined to match the chemical properties of the actual fuel. A kinetic mechanism was defined by pairing each pseudo-component with a reaction to describe its thermal decomposition. The model was then validated against literature data and demonstrated to be predictive in describing the pyrolysis of different samples.