UPGRADING
CHARACTERIZATION OF ASPHALTENE FRACTIONS FROM
GEL PERMEATION CHROMATOGRAPHY USING NUCLEAR
MAGNETIC RESONANCE SPECTROSCOPY, HIGH
TEMPERATURE SIMULATED DISTILLATION AND VAPOR
PRESSURE OSMOMETRY
Adrienne M. Inman1, Sara L. Salmon1, Heather D. Dettman1,
Kerry T. Scott2, and Bryan J. Fuhr2
1
National Centre for Upgrading Technology, Devon, Alberta, Canada
2
Alberta Research Council, Edmonton, Alberta, Canada.
Molecular characterization of petroleum feeds is important for understanding and
modeling the upgrading processes used for producing high-value products. For
petroleum fractions with boiling ranges below 524C (distillates), gas chromatography
(GC) fitted with a mass spectrometer (MS) detector has proven valuable in quantifying
classes of compounds in petroleum. At NCUT, GC-MS data of distillates has been put
together with simulated distillation data to allow saturates and aromatics content
information to be distributed by boiling point. Such information is important for
developing reactor and process models.
For petroleum fractions with boiling ranges above 524C (resid), GC-MS cannot
be used. However, resid samples can be easily analyzed using nuclear magnetic
resonance (NMR) techniques. At NCUT, NMR is used to quantify resid carbon types
including aromatic, olefin, paraffin, branched-paraffin, and cycloparaffin species.
However, the information is averaged over the entire sample, making it less useful for
modeling purposes.
Currently, we are developing a method for separating resid components into
thermal chemistry-meaningful subfractions. Resids are separated by adsorption
chromatography and solubility into saturates, aromatics, resins, and asphaltenes (SARA)
fractions. Each of these fractions is further separated by size using gel permeation
chromatography. This study focuses on Athabasca pentane-asphaltenes that have been
distributed over more than 20 sub-fractions with average molecular weights, determined
by vapor pressure osmometry, ranging from 700 g/mole to 20,000 g/mole. High
temperature simulated distillation and NMR carbon-type analyses show how the boiling
point ranges and distributions of carbon types change with average molecular size for
these pentane-insoluble compounds.