Molecular Weight Determination of Asphaltenes from Colombian Crudes by Size Exclusion Chromatography (SEC) and Vapor Pressure Osmometry (VPO)
2009; Taylor & Francis; Volume: 27; Issue: 8 Linguagem: Inglês
10.1080/10916460802455491
ISSN1532-2459
AutoresAlexander Guzmán, Alexis Bueno, Lante Carbognani,
Tópico(s)Enhanced Oil Recovery Techniques
ResumoAbstract Characterization of Colombian asphaltenes isolated from feedstocks to refining units was carried out during this study, emphasizing the determination of their average molecular weights (MW). Experimental conditions used for vapor pressure osmometry (VPO) and size exclusion chromatography (SEC) were investigated aiming to select the most suitable set up that affords the best representative values. SEC was observed to provide the most reasonable MW values, after analysis improvements were achieved by using realistic calibration curves got with phthalocyanines, compounds that closely mimic component structures within oil and asphaltenes fractions. MWs displayed by Colombian vacuum residua asphaltenes fall within the range 1,700 ± 200 Daltons, reported previously for asphaltenes from different reservoirs worldwide. Keywords: asphaltenesmolecular weightsize exclusion chromatographyvapor pressure osmometrypetroleumphthalocyaninesPCs ACKNOWLEDGMENTS The authors are grateful to Ecopetrol S. A. for its economical support through the “Convenio de Cooperación Tecnológica 003 de 2007” between Ecopetrol and Universidad Industrial De Santander (UIS) and “Convenio de Cooperación Tecnológica 004 de 2003” between Ecopetrol and Universidad Industrial de Santander (UIS), Universidad Nacional de Colombia (UNAL) and Universidad de Antioquía (UdeA). Notes * fa = Aromaticity factor
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