నైరూప్య

Characterization of aromatic fractions separated from the heavy residual fractions of four crude oils having different geological origins by HPLC and NMR

Manoj Kumar Sarmah, Arun Borthakur,Aradhana Dutta

Four crude oils having different geological origins such as DK (Sylhet limestone and Langpar), SL (Oligocene), JN (lower Miocene) and KMC (upper to middle Miocene) were taken from four different locations and distilled at atmospheric pressure up to 300 degrees C. Aromatic fractions were separated from the 300 degrees C+ fractions (feedstock) by medium pressure liquid chromatography (MPLC). The separated aromatic fractions were characterized by high performance liquid chromatographywith photo diode array detector (HPLC-PDA) for aromatic group type analysis and by 1H and 13C NMR for aromatic structure type analysis. Different aromatic groups likemono-, di-, tri-, tetra etc.were separated and quantified byHPLC. The combined gained information from NMR analysis provided reliable average structural parameters. These included estimation of aliphatic and aromatic content, average paraffinic chain length, polyaromatic compounds etc.