Sulfur dioxide extraction process

Claim 1

A METHOD FOR THE SEPARATION AND RECOVERY OF AROMATIC HYDROCARBONS FROM A CRACKED GASOLINE FEED STOCK CONTAINING AROMATIC AND NONAROMATIC HYDROCARBONS COMPRISING SOLVENT EXTRACTING IN A FIRST EXTRACTION OPERATION SAID FEED STOCK WITH LIQUEFIED SULFUR DIOXIDE IN THE PRESENCE OF A FIRST PORTION OF A PARAFFINIC HYDROCARBON MATERIAL BOILING AT A TEMPERATURE ABOVE THE END BOILING POINT OF SAID FEED STOCK AND AS SUBSEQUENTLY PRODUCED, THE RATIO OF SAID SULFUR DIOXIDE TO SAID FIRST PORTION OF PARAFFINIC HYDROCARBON MATERIAL BEING MAINTAINED IN A RATIO OF ABOUT 2 TO 1, FROM THIS FIRST EXTRACTION OPERATION SEPARATING A FIRST EXTRACT PHASE AND A FIRST RAFFINATE PHASE, SOLVENT EXTRACTING IN A SECOND EXTRACTION OPERATION SAID FIRST EXTRACT PHASE WITH A SECOND PARAFFINIC HYDROCARBON MATERIAL BOILING AT A TEMPERATURE ABOVE THE END BOILING POINT OF SAID FEED STOCK AND AS SUBSEQUENTLY PRODUCED, THE RATIO OF THE SULFUR DIOXIDE TO THE SECOND PARAFFINIC HYDROCARBON MATERIAL IN SAID SECOND EXTRACTION OPERATION BEING ABOUT 1 TO 1, FROM THIS SECOND EXTRACTION OPERATION SEPARATING A SECOND RAFFINATE PHASE COMPRISING AROMATIC HYDROCARBONS AND A SECOND EXTRACT PHASE COMPRISING SAID SECOND PARAFFINIC HYDROCARBON MATERIAL BOILING AT A TEMPERATURE ABOVE THE END BOILING POINT OF SAID FEED STOCK, AROMATIC AND NON-AROMATIC HYDROCARBONS, DIVIDING SAID SECOND EXTRACT PHASE INTO TWO PORTIONS, INTRODUCING ONE PORTION INTO SAID FIRST EXTRACTION OPERATION AS SAID FIRST PORTION OF A PARAFFINIC HYDROCARBON MATERIAL AS SUBSEQUENTLY PRODUCED, DISTILLING THE OTHER PORTION OF SAID SECOND EXTRACT PHASE TO PRODUCE A BOTTOMS PRODUCT COMPRISING SAID SECOND PARAFFINIC HYDROCARBON MATERIAL AND AN OVERHEAD PRODUCT COMPRISING SULFUR DIOXIDE, AROMATIC AND NON-AROMATIC HYDROCARBONS, PASSING SAID BOTTOMS PRODUCT TO THE SECOND EXTRACTING OPERATION AS SAID SECOND PARAFFINIC HYDROCARBON MATERIAL SUBSEQUENTLY PRODUCED AND INTRODUCING THE LATTER OVERHEAD PRODUCT INTO THE FIRST EXTRACTION OPERATION.

Claim 2

A METHOD FOR THE SEPARATION AND RECOVERY OF AROMATIC HYDROCARBONS FROM A CRACKED GASOLINE FEED STOCK CONTAINING AROMATIC AND NONAROMATIC HYDROCARBONS COMPRISING SOLVENT EXTRACTING IN A FIRST EXTRACTION OPERATION SAID FEED STOCK WITH LIQUEFIED SULFUR DIOXIDE IN THE PRESENCE OF A FIRST PORTION OF A PARAFFINIC HYDROCARBON MATERIAL BOILING AT A TEMPERATURE ABOVE THE END BOILING POINT OF SAID FEED STOCK AND AS SUBSEQUENTLY PRODUCED, THE RATIO OF SAID SULFUR DIOXIDE TO SAID FIRST PORTION OF PARAFFINIC HYDROCARBON MATERIAL BEING MAINTAINED IN A RATIO OF ABOUT 2 TO 1, FROM THIS FIRST EXTRACTION OPERATION SEPARATING A FIRST EXTRACT PHASE AND A FIRST RAFFINATE PHASE, SOLVENT EXTRACTING IN A SECOND EXTRACTION OPERATION SAID FIRST EXTRACT PHASE WITH A SECOND PARAFFINIC HYDROCARBON MATERIAL BOILING AT A TEMPERATURE ABOVE THE END BOILING POINT OF SAID FEED STOCK AND AS SUBSEQUENTLY PRODUCED, THE RATIO OF THE SULFUR DIOXIDE TO THE SECOND PARAFFINIC HYDROCARBON MATERIAL IN SAID SECOND EXTRACTION OPERATION BEING ABOUT 1 TO 1, FROM THIS SECOND EXTRACTION OPERATION SEPARATING A SECOND RAFFINATE PHASE COMPRISING AROMATIC HYDROCARBONS AND A SECOND EXTRACT PHASE COMPRISING SAID SECOND PARAFFINIC HYDROCARBON MATERIAL BOILING AT A TEMPERATURE ABOVE THE END BOILING POINT OF SAID FEED STOCK, AROMATIC AND NON-AROMATIC HYDROCARBONS, DIVIDING SAID SECOND EXTRACT PHASE INTO TWO PORTIONS, INTRODUCING ONE PORTION INTO SAID FIRST EXTRACTION OPERATION AS SAID FIRST PORTION OF A PARAFFINIC HYDROCARBON MATERIAL AS SUBSEQUENTLY PRODUCED, DISTILLING THE OTHER PORTION OF SAID SECOND EXTRACT PHASE TO PRODUCE A BOTTOMS PRODUCT COMPRISING SAID SECOND PARAFFINIC HYDROCARBON MATERIAL AND AN OVERHEAD PRODUCT COMPRISING SULFUR DIOXIDE, AROMATIC AND NON-AROMATIC HYDROCARBONS, PASSING SAID BOTTOMS PRODUCT TO THE SECOND EXTRACTING OPERATION AS SAID SECOND PARAFFINIC HYDROCARBON MATERIAL SUBSEQUENTLY PRODUCED AND INTRODUCING THE LATTER OVERHEAD PRODUCT INTO THE FIRST EXTRACTION OPERATION.