Experimental Determination and Characterization of Wax Fractions Precipitated as a Function of Temperature

Wax precipitation at low temperatures in petroleum mixtures is one of the most important problems in flow assurance. Experimental quantification of such processes and the further characterization of the precipitated mixtures are very difficult and extremely time-consuming, and therefore, the available experimental information is scarce and usually not very confident. In this work, wax samples were precipitated from two crude oils at different temperatures and they were characterized by optical microscopy, elemental analysis, 1H NMR spectroscopy, differential scanning calorimetry (DSC), and mass spectroscopy. The obtained results show the presence of different compounds in such mixtures regarding the chemical nature of the crude oil. The well-known presence of soaked crude oils in the precipitated fractions was experimentally estimated from 1H NMR and mass spectroscopy, and the obtained results suggest a decrease in the soaked crude oil amount as the precipitation temperature becomes lower, in agreement wi...