Determination of Monoaromatic Fraction in Saturate Fraction Separated by JPI Standard (JPI-5S-22-83) and Modified JPI Method

摘要

Saturate fractions separated by the JPI standard and DS methods, which is about a quarter-scale separation of the JPI standard, from maltenes (pentane-soluble fraction) in Middle East vacuum residue (ME) and Cold Lake oil sand bitumen atmospheric residue (CL), were analyzed by a HPLC system equipped a series of amino-modified silica-gel columns, an ultraviolet (UV, dual wavelength mode) detector and an evaporate light scattering detector (ELSD) using hexane as an eluent. All saturate fractions showed two peaks. The first one was assigned as non aromatics, and the second one, monoaromatics, because only the second one showed a peak by UV detector at 270 nm, but no peaks at 320 nm. These peaks were determined after the correction of base line and intensity, since ELSD has an exponentially response with concentration. In an additional separation test by DS methods, the heptane eluent was collected into four subfractions, and those peaks were observed only in the first two sub fractions. Another separation test was performed using a model sample (MO) including compounds having two benzene rings in a molecule (diphenyls). The heptane and toluene eluents were collected into four subfractions, respectively, then analyzed by gas chromatography. Diphenyls were observed in the last two subfractions of heptane and the first subfraction of toluene elutions. From the results, diphenyls could not determine by themselves, but as a part of polyaromatics. As a result, ME and CL contained practically no diphenyls. In conclusion, the combination of the JPI/DS methods and HPLC analysis provides the distribution of four types, nonaromatics, monoaromatics, polyaromatics and resins in maltene.