Patent ID: 6890425

Claim:
A method of refining a petroleum product comprising: providing an unrefined petroleum product containing a first petroleum fraction and a second fraction to be separated, which includes aromatic hydrocarbons, the first petroleum fraction having a melt point temperature, and wherein the unrefined petroleum product contains an amount of extractant, the extractant having a freezing point temperature that is greater than the melt point temperature of the first petroleum fraction, the unrefined petroleum product being at or above the pour point temperature of the unrefined petroleum product so that the extractant is in a substantially liquefied state with the first petroleum fraction being substantially dissolved within the extractant; admixing with the unrefined petroleum product a solvent in which the second fraction is soluble so that the second fraction is dissolved within the solvent, and wherein the extractant is substantially insoluble within the solvent; bringing the mixture of unrefined petroleum product and solvent to a temperature below the freezing point temperature of the extractant so that the extractant containing the dissolved first petroleum fraction is crystallized and the solvent containing the dissolved second fraction is in a liquid phase; and separating the crystallized extractant containing the dissolved first petroleum fraction from the liquid phase.