Abstract: Four standard methods (SY/T 0537, SY/T 7550, ГОСТ 11851 and UOP 46) for determining wax content in crude oil are compared. Significant differences and certain regularities among the wax content results obtained by these methods are observed. The wax contents obtained from high to low are in the order of UOP 46> SY/T 0537> SY/T 7550> ГОСТ 11851. It can be seen that in these four methods, the dewaxing conditions, solvent compositions and the solubility of wax in solvent are varied, which leads to the differences of results obtained by each method. Furthermore, based on the analysis of wax compositions it is found that the differences are mainly caused by the various solubilities of ≤C25 n-paraffins and other hydrocarbons in the individual solvent under individual dewaxing conditions.

Key words: crude oil, wax, analytical method