Extraction process

Claim 1

THE PROCESS FOR THE SEPARATION OF AROMATIC HYDROCARBONS FROM HYDROCARBON MIXTURES CONTAINING AROMATIC HYDROCARBONS OF DIFFERENT BOILING POINTS IN ADMIXTURE WILTH NON-AROMATIC HYDROCARBONS, WHICH COMPRISES CONTACTING SAID HYDROCARBON MIXTURE WITH AN N-SUBSTITUTED CARBAMATE SOLVENT IN A PRIMARY EXTRACTION ZONE, SEPARATING AN AROMATIC HYDROCARBON SOLVENT EXTRACT AND A NONAROMATIC RAFFINATE FROM SAID PRIMARY EXTRACTION ZONE, WASHING SAID NON-AROMATIC RAFFINATE WITH WATER IN A RAFFINATE WASH ZONE, SEPARATING A PURFIED RAFFINATE AND A FIRST SOLVENT-WATER-CONTAINING MIXTURE FROM SAID RAFFINATE WASH ZONE, CONTACTING SAID AROMATIC HYDROCARBON SOLVENT EXTRACT WITH A PARAFFINIC HYDROCARBON, HAVING BOILING POINT ABOVE THE BOILING POINT OF THE DESIRED AROMATIC HYDROCARBONS IN SAID HYDROCARBON MIXTURE, IN A SECONDARY EXTRACTION ZONE, SEPARATING A SOLVENT-CONTAINING RAFFINATE AND AN AROMATIC HYDROCARBON-PARAFFINIC HYDROCARBON EXTRACT FROM SAID SECONDARY EXTRACTION ZONE, CONTACTING SAID AROMATIC HYDROCARBON-PARAFFINIC HYDROCARBON EXTRACT WITH A WATER-HEAVER AROMATIC HYDROCARBON BOTTOMS, SUBSEQUENTLY TO BE DEFINED, IN AN EXTRACT WASH ZONE, THEREBY SEPARATING SAID LAST-MENTIONED EXTRACT INTO A SECOND SOLVENT-WATER-CONTAINING MIXTURE AND A PARAFFINIC HYDROCARBON-AROMATIC HYDROCARBON FRACTION IN SAID EXTRACT WASH ZONE, HEATING SAID PARAFFINIC HYDROCARBON-AROMATIC HYDROCARBON FRACTION IN AN AROMATIC HYDROCARBON RECOVERY ZONE, RECOVERING AN OVERHEAD COMPRISING THE DESIRED AROMATIC HYDROCARBONS AND A BOTTOMS COMPRISING HOT PARAFFINIC HYDROCARBONS CONTAINING SAID HEAVIER AROMATIC HYDROCARBONS FROM SAID AROMATIC HYDROCARBON RECOVERY ZONE, HEATING SAID FIRST AND SECOND SOLVENT-WATER-CONTAINING MIXTURES ALONG WITH SAID SOLVENT-CONTAINING RAFFINATE IN A SOLVENT RECOVERY ZONE, SEPARATING AN OVERHEAD COMPRISING SUBSTANTIALLY CONCENTRATED SOLVENT AND A WATERHEAVIER AROMATIC HYDROCARBON BOTTOMS AS BOTTOMS FROM SAID SOLVENT RECOVERY ZONE, RECYCLING AT LEAST A PORTION OF SAID WATER-HEAVIER AROMATIC HYDROCARBON BOTTOMS TO SAID EXTRACT WASH ZONE, AND SEPARATING A PORTION OF SAID HOT PARAFFINIC HYDROCARBON BOTTOMS CONTAILNING SAID HEAVIER AROMATIC HYDROCARBONS TO PREVENT THE BUILD-UP OF THE LATTER IN THE SYSTEM.