The interaction energies between asphaltenes and real complex maltene fractions (i.e. saturates, aromatics, and resins) from petroleum residue have been determined by differential scanning calorimetry (DSC). Phase behaviors of asphaltenes dispersed in three maltene fractions have also been correspondingly observed using an optical microscope. Results show that endothermic interactions are found at elevated temperature in all types of mixtures, while exothermic effect is observed after 143oC in the mixture of saturates with asphaltenes, which could be related to the aggregation of asphaltenes in the system. The enthalpy of interaction varies in intensity and range as the composition of dispersion medium differs, which are quantitatively integrated as -2.3, -6.8, and -7.4J/g for saturates, aromatics, and resins, respectively. It is deduced that interaction enthalpy could be used as a quantitative criterion for the peptization ability of dispersion medium and further possible determination of compatibility of heavy oil system.

Calorimetric probing of interactions of asphaltenes with saturates, aromatics, and resins in petroleum residue

245th National Meeting (2013)

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