The role of deasphalted oil in the stability of asphaltenes
Conference Paper
Overview
Identity
Additional Document Info
View All
Overview
abstract
Asphaltenes represent the heaviest fraction of the crude oil. The physical and chemical variations during oil production destabilize the asphaltene molecules and cause asphaltene precipitation. This work deals with the analysis of the change in asphaltene phase behavior due to the compositional variations. Two crude oil samples which have different asphaltene content, API gravity, and viscosity were examined. The stability of asphaltenes was investigated by defining each crude oil with a four-component system. Hence, the crude oils were divided into their Saturates, Aromatics, Resins, and Asphaltenes (SARA) fractions by following a standard method which uses n-pentane to separate asphaltenes. First, the spectral characterization on the crude oils and on their SARA fractions was achieved by Fourier Transform InfraRed (FTIR) spectroscopy. Indirect assessment of the polarity of the crude oil and its fractions were also carried out using dielectric constant measurements. Then, ternary phase diagrams were constructed by using the blending of saturated (n-pentane) and aromatic (toluene) hydrocarbons with asphaltenes fraction at varying amounts. The three-component two-phase (solid-liquid) diagrams have been constructed based on experimental data. Asphaltenes are soluble in aromatic solvents and insoluble in normal alkanes, thus, while the increase in amount of n-pentane decreases the asphaltene stability, the increase in toluene reestablishes the stabilization. While the systematic analyses conducted in this study enhance our understanding, it is necessary to observe behavior of asphaltenes after the interaction with crude oils own saturates and aromatics fractions which would provide better insights towards the role of deasphalted crude oil fractions in maintaining the stabilit y of asphaltenes.
4th International Conference on Upstream Engineering and Flow Assurance 2016 - Topical Conference at the 2016 AIChE Spring Meeting and 12th Global Congress on Process Safety
