Molecular thermodynamics for prevention of asphaltene precipitation

Technical Report · Sat Jun 01 04:00:00 EDT 1996

DOI:https://doi.org/10.2172/374166· OSTI ID:374166

Wu, Jianzhong; Prausnitz, J M

Crude petroleum is a complex mixture of compounds with different chemical structures and molecular weights. Asphaltenes, the heaviest and most polar fraction of crude oil, are insoluble in normal alkanes such as n-heptane, but they are soluble in aromatic solvents such as toluene. The molecular nature of asphaltenes and their role in production and processing of crude oils have been the topic of numerous studies. Under some conditions, asphaltenes precipitate from a petroleum fluid, causing severe problems in production and transportation Our research objective is to develop a theoretically based, but engineering-oriented, molecular-thermodynamic model which can describe the phase behavior of asphaltene precipitation in petroleum fluids, to provide guidance for petroleum-engineering design and production. In this progress report, particular attention is given to the potential of mean force between asphaltene molecules in a medium of asphaltene-free solvent. This potential of mean force is derived using the principles of colloid science. It depends on the properties of asphaltene and those of the solvent as well as on temperature and pressure. The effect of a solvent on interactions between asphaltenes is taken into account through its density and through its molecular dispersion properties.

• Research Organization: Lawrence Berkeley Lab., CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 374166
• Report Number(s): LBNL--38991; ON: DE96014983
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
99 GENERAL AND MISCELLANEOUS
ALKANES
ASPHALTENES
CHEMICAL COMPOSITION
FLUIDS
MATHEMATICAL MODELS
MOLECULES
PETROLEUM
PRECIPITATION
PROCESSING
SOLVENTS
THERMODYNAMICS