화학공학소재연구정보센터
Energy & Fuels, Vol.23, No.1, 888-893, 2009
Compositional and Structural Analysis of Lubricating Oil Feedstock Obtained from a Light Crude Oil
Vacuum distillate cuts are used as feedstock in the lubricating oil manufacturing process. In this work, compositional and structural characterization of three vacuum distillate cuts was carried out. Composition of distillate cuts was determined in term of saturates, aromatics, and polars using the ASTM D2007 standard test method. The aromatic fraction was analyzed by HPLC to obtain the distribution of aromatic compounds in mono-, di-, and polyaromatic hydrocarbons. Saturate and aromatic fractions were analyzed for elemental carbon, hydrogen, and sulfur and for molecular weight. Proton and carbon nuclear magnetic resonance spectroscopy were applied to determine the average molecular structure of the hydrocarbons present in both fractions. The average molecular structure of the saturate hydrocarbons contained one naphthenic ring with an n-alkyl chain length of 18-22 carbon atoms and different branches. The average molecular structure of the aromatic fractions was made up of an aliphatic and an aromatic part. The aliphatic part is formed by one (light distillates cuts) or two cycloparaffinic rings (heavy distillate cut) and the n-alkyl chain length increasing with the boiling point of the distillate cut. The aromatic part was similar for all distillate cuts. Mono- and diaromatics showed, respectively, one or two aromatic rings fused to cycloparaffinic structures. Polyaromatics showed similar structure to that for the diaromatics, but including a thiophenic ring bridged to two aromatic rings.