Method of refining oil with a solvent

Claim 1

IN THE SOLVENT REFINING OF FEED OIL OF THE CLASS CONSISTING OF KEROSENE AND GAS OIL CONTAINING AT LEAST A SMALL PROPORTION OF NATURALLY OCCURRING CONSTITUENTS HAVING TRUE BOILING POINTS IN THE RANGE OF THE SOLVENT BOILING TEMPERATURE AND BELOW WHEREIN THE FEED OIL IS SUBJECTED TO CONTRACT IN AN EXTRACTION TOWER IN THE PRESENCE OF WATER WITH A WATER MISCIBLE ORGANIC SOLVENT LIQUID HAVING SELECTIVE SOLVENT ACTION AS BETWEEN PARAFFINIC AND NON-PARAFFINIC CONSTITUENTS OF THE OIL, EXTRACT AND RAFFINATE PHASES RESPECTIVELY LEAN AND RICH IN PARAFFINIC CONSTITUENTS OF THE OIL ARE FORMED, SAID PHASES SEPARATELY REMOVED FROM THE EXTRACTION ZONE, EACH OF SAID REMOVED PHASES COMPRISING OIL, SOLVENT AND WATER, AND THE REMOVE PHASES TREATED TO RECOVER SOLVENT FROM THE OIL FOR REUSE IN THE EXTRACTION ZONE, THE METHOD COMPRISING RECOVERING SOLVENT FROM THE REMOVED RAFFINATE PHASE, RECYCLING SO-RECOVERED SOLVENT TO THE EXTRACTION ZONE, SEPARATELY DISTILLING FROM SAID EXTRACT PHASE IN THE PRESENCE FO ADDED WATER IN A PRIMARY FRACTIONATING ZONE, A DISTILLATE CONTAINING TERNARY AZEOTROPE OF SOLVENT, OIL AND WATER, THE OIL IN SAID AZEROTROPE BEING THE RELATIVELY PARAFFINIC PORTION OF THE EXTRACT OIL AND AMOUNTING TO A RELATIVELY MINOR PROPORTION OF THE EXTRACT OIL, AND FORMING A RESIDUAL LIQUID FRACTION COMPRISING THE MAIN BODY OF SOLVENT LIQUID CONTAINED IN THE EXTRACT PHASE REMOVED FROM THE EXTRACTION ZONE AND IN ADDITION THE REMAINDER AND MAJOR PORTION OF THE EXTRACT OIL, SUBSTANTIALLY COMPLETELY CONDENSING SAID PRIMARY DISTILLATE, SUBJECTING RESULTING CONDENSATE TO SETTLING IN A PRIMARY SETTLING ZONE THEREBY FORMING OIL-RICH, WATER-RICH AND SOLVENT-RICH LIQUID LAYERS RESPECTIVELY, SAID OIL-RICH LAYER COMPRISING SUBSTANTIALLY ALL OF SAID AZEOTROPE OIL, RECYCLING SAID OIL-RICH LAYER TO THE EXTRACT PHASE ZONE OF THE EXTRACTION TOWER, RECYCLING SAID SOLVENT-RICH LAYER TO THE RAFFINATE ZONE OF SAID EXTRACTION TOWER, RECYCLING AT LEAST A PORTION OF THE WATER-RICH LAYER AS REFLUX TO THE PRIMARY FRACTIONATING ZONE, PASSING SAID RESIDUAL LIQUID FRACTION TO A SECOND FRACTIONATING ZONE, SUBJECTING IT THEREIN TO DISTILLATION IN THE PRESENCE OF WATER TO FORM A SECOND DISTILLATE OF TERNARY AZEOTROPE CONTAINING SUBSTANTIALLY ALL OF THE REMAINING EXTRACT OIL, AND A SECOND RESIDUAL LIQUID FRACTION COMPRISING SUBSTANTIALLY OIL-FREE SOLVENT, SAID OIL-FREE SOLVENT BEING THE BULK OF THE SOLVENT REMOVED FROM THE EXTRACTION ZONE IN THE EXTRACT PHASE, RETURNING SAID OILFREE SOLVENT FRACTION TO THE EXTRACTION ZONE, CONDENSING SAID SECONDARY DISTILLATE AND SEPARATELY RECOVERING EXTRACT OIL AND RESIDUAL SOLVENT THEREFROM.