Characterization of libyan waxy crude oils
Résumé
The prediction of wax formation and the understanding of the physicochemical characteristics of the wax phase are of major importance in flow assurance. The characterization of the oil and wax can provide useful estimates of the parameters and behavior required for operational engineering process developments and/or physical modifications to the processing of crude oils, aiming at the reduction of costs of production and transportation. Five Libyan crude oils and their waxes were characterized using various experimental techniques. Waxes were extracted using the Universal Oil Products (UOP) 46-64 method and purified by column chromatography. Differential scanning calorimetry (DSC) and cross polar microscopy (CPM) techniques were used to study the wax appearance temperature (WAT) for these crude oils. Waxes were characterized using gas chromatography (GC), nuclear magnetic resonance (NMR), and X-ray diffraction (XRD). The carbon number distribution was determined by gas chromatography-flame ionization detector (GC-FID). Extensive information about the structural composition of these waxes was performed using 13C NMR, and information for the crystalline structure of these waxes was obtained using XRD. This study shows that the five Libyan crude oils studied have wax contents between 8 and 24 wt % with WAT in the range of 22.5-68.17 °C. The isolated waxes are shown to be paraffinic (macrocrystalline wax) with an orthorhombic structure.
Mots clés
Carbon number distribution
Crystalline structure
Engineering process
Experimental techniques
Flow assurance
Gas chromatography-flame ionization detectors
Macrocrystalline
Oil product
Orthorhombic structures
Physical modifications
Physicochemical characteristics
Structural composition
Wax appearance temperature
Wax content
Wax formation
Waxy Crude Oil
XRD Engineering controlled terms: Biomaterials
Crude oil
Differential scanning calorimetry
Gas chromatography
Gas generators
Ionization of gases
Nuclear magnetic resonance
Petroleum transportation
Resonance
X ray diffraction Engineering main heading: Column chromatography