Method of operating an hf alkylation unit

Claim 1

IN A PROCESS FOR REACTING A LOW-BOILING ALKYLATABLE HYDROCARBON AND AN ALKYLATING REACTANT TO PRODUCE HIGHER-BOILING HYDROCARBONS, THE IMPROVEMENT WHICH COMPRISES PASSING A LIQUID HYDROCARBON MATERIAL COMPRISING LOW-BOILING HYDROCARBON EFFLUENTS OF SUCH A REACTION AND INCLUDING HIGHER-BOILING HYDROCARBON PRODUCTS AND CONTAINING DISSOLVED HYDROGEN FLUORIDE TO A FIRST FRACTIONAL DISTILLATION MEANS, INTRODUCING INTO MATERIAL UNDERGOING DISTILLATION IN SAID FIRST MEANS A LOW-BOILING OLEFINIC HYDROCARBON MATERIAL OF WHICH NO OLEFIN FORMS A CORRESPONDING ALKYL FLUORIDE HAVING A HIGHER BOILING POINT THAN SAID LOWBOILING ALKYLATABLE HYDROCARBON, SAID MATERIAL CONTAINING SUFFICIENT OLEFIN TO REACT WITH ALL HYDROGEN FLUORIDE ASSOCIATED WITH SAID HYDROCARBON EFFLUENTS AND FORM THE CORRESPONDING ALKYL FLUORIDE, REMOVING FROM SAID FIRST MEANS A HIGH-BOILING FRACTION COMPRISING UNREACTED ALKYLATABLE HYDROCARBON AND HIGHER-BOILING HYDROCARBONS PRODUCED IN SAID REACTION AND RESULTING ALKYL FLUORIDE AND PASSING SAME TO A SECOND FRACTIONAL DISTILLATION MEANS, REMOVING FROM SAID SECOND MEANS A LOWBOILING FRACTION COMPRISING SAID ALKYLATABLE HYDROCARBON AND ALKYL FLUORIDE PRODUCED FROM SAID ADDED OLEFIN AND PASSING SAME TO AN ALKYLATION REACTION, AND REMOVING ALSO FROM SAID SECOND MEANS A HIGH-BOILING FRACTION COMPRISING HIGHER-BOILING HYDROCARBONS PRODUCED BY SAID REACTION AS A PRODUCT OF THE PROCESS.