Separation of aromatics by so2 extraction

Claim 1

IN THE SEPARATION OF AN AROMATIC HYDROCARBON SELECTED FROM THE GROUP OF AROMATIC HYDROCARBONS CONSISTING OF BENZENE AND THE XYLENES FROM ADMIXTURE WITH A PARAFFIN HYDROCARBON DIFFICULTLY SEPARABLE THEREFROM BY DISTILLATION, THE IMPROVEMENT COMPRISING MIXING SAID ADMIXTURE OF HYDROCARBONS WITH LIQUID SULFUR DIOXIDE, SUBJECTING THIS MIXTURE TO SOLVENT EXTRACTION CONDITIONS, SEPARATING AN EXTRACT PHASE FROM A RAFFINATE PHASE, REMOVING DISSOLVED SULFUR DIOXIDE FROM THE PARAFFIN HYDROCARBONS OF THE RAFFINATE PHASE AND RECOVERING THE PARAFFIN HYDROCARBONS AS ONE PRODUCT OF THE PROCESS, REMOVING BY FLASHING SULFUR DIOXIDE FROM THE EXTRACT PHASE AND THEREBY CHILLING THE UNVAPORIZED MATERIAL, SEPARATING BY GRAVITY SEPARATION THE CHILLED UNVAPORIZED MATERIAL INTO A PARAFFIN HYDROCARBON-RICH LIQUID PHASE AND A LIQUID PHASE RICH IN SAID AROMATIC HYDROCARBON, AND CONTAINING SULFUR DIOXIDE, WITHDRAWING THESE PHASES, AND FURTHER CHILLING THE WITHDRAWN AROMATIC HYDROCARBON-RICH PHASE CONTAINING SULFUR DIOXIDE TO A TEMPERATURE FOR CRYSTALLIZING SAID AROMATIC HYDROCARBON AND ABOVE THE AROMATIC HYDROCARBON-SULFUR DIOXIDE EUTECTIC TEMPERATURE TO FORM CRYSTALS OF SAID AROMATIC HYDROCARBON, FROM THIS AROMATIC HYDROCARBON FREEZING OPERATION SEPARATING A PHASE RICH IN SULFUR DIOXIDE AND A SLURRY COMPRISING CRYSTALLINE AROMATIC HYDROCARBON AND LIQUID SULFUR DIOXIDE INTRODUCING THIS SLURRY INTO A PURIFIER ZONE, EXPRESSING LIQUID FROM THE AROMATIC HYDROCARBON CRYSTALS, REMOVING THE EXPRESSED LIQUID, MELTING THE AROMATIC HYDROCARBON CRYSTALS RESULTING FROM THE EXPRESSING OPERATION, AND RECOVERING THE MELTING AROMATIC HYDROCARBON AS A SECOND PRODUCT OF THE PROCESS.