Method of recovering hydrogen fluoride in an alkylation process

Claim 1

IN A PROCESS FOR THE ALKYLATION OF ALKYLATABLE PARAFFINS WITH OLEFINS WHICH COMPRISES SUBJECTING ALKYLATABLE PARAFFINS AND OLEFINS TO CONTACT UNDER ALKYLATION CONDITIONS IN AN ALKYLATION ZONE WITH HYDROGEN FLUORIDE CATALYST; SEPARATING A REACTION MIXTURE EFFUENT FROM SAID ALKYLATION ZONE INTO A HYDROCARBON PHASE AND A CATALYST PHASE; PASSING AT LEAST A PORTION OF SAID CATALYST PHASE TO A FRACTIONATION ZONE; REMOVING A MIXTURE OF HYDROGEN FLUORIDE AND LOW BOILING HYDROCARBONS FROM AN UPPER PORTION OF SAID FRACTIONATION ZONE; RETURNING AT LEAST A PORTION OF SAID MIXTURE TO SAID ALKYLATION ZONE; WITHDRAWING A STREAM COMPRISING LIGHT ACID-SOLUBLE ORGANIC MATERIAL AND HYDROGEN FLUORIDE INTERMEDIATE AN UPPER PORTION AND A LOWER PORTION OF SAID FRACTIONATION ZONE; PASSING SAID STREAM TO A SETTLING ZONE WHERE A HYDROCARBON PHASE IS SEPARATED THEREFROM; PASSING SAID RESULTING HYDROCARBON PHASE TO A STRIPPING ZONE AND REMOVING THEREFROM ABSORBED HYDROGEN FLUORIDE; AND RETURNING THE RESULTING HYDROGEN FLUORIDE TO AN UPPER PORTION OF SAID FRACTIONATION ZONE.