The deasphalting of heavy crude oil by silicone oil is a green method of removing heavy compounds and producing bitumen

Abstract

Deasphalting of heavy crude oil (HCO) with silicone oil (SO), which is immiscible with the crude oil and extracts light compounds from it, has been carried out for the first time. The yield of the extracted light fraction increases linearly with increasing SO/HCO ratio from 0.5/1 to 10/1 and then reaches a constant level of about 50%. An analysis of the composition and properties of the precipitated heavy fractions showed that they are enriched with asphaltenes and resins but contain admixtures of saturated and aromatic compounds. Compared with the original crude oil, the heavy fractions have a higher viscosity that correlates with sulfur concentration and tends to become higher as the SO/HCO ratio increases. Moreover, the viscoelastic properties of the heavy fractions are similar to those of bitumen binders, allowing their potential use in road construction. In this case, SO/HCO ratios of 15/1 and 25/1 make it possible to produce bitumens as a byproduct that meet existing standards for binder's viscosity and thermal stability. A comparative evaluation of energy consumption has shown the advantage of silicone oil usage for deasphalting of heavy oil in comparison to usual solvent deasphalting with volatile and environmentally unfriendly aliphatic hydrocarbons.