Evaluation of Methods for the Extraction and Characterization of Waxes from Crude Oils

Wax precipitation is one of the most important flow assurance problems. The adequate characterization of the content and composition of the waxes present in the oil is one of the major obstacles in dealing with this issue. In this work, two different methods for the extraction of waxes from different crude oils are compared. The methods used differ significantly with regard to the separation of waxes from asphalthenes. Further purification of parafffins for characterization was carried out using sequential elution chromatography. The n-paraffin distribution determined by gas chromatography along with wax melting temperature and total n-paraffin content determined by differential scanning calorimetry show remarkable differences in the waxes depending upon the precipitation method used. The separation carried out by method 1 allows for heavier n-alkanes to be retained but with a higher content of impurities, as revealed by their lower melting points and n-paraffin content. Method 2 provides a better purific...