Method of recovering anhydrous aluminum chloride from fluid aluminum-hydrocarbon complex

Claim 1

THE IMPROVED METHOD OF RECOVERING ANHYDROUS ALUMINUM CHLORIDE FROM A LIQUID ALUMINUM CHLORIDE-HYDROCARBON COMPLEX CONTAINING DISSOLVED HYDROGEN CHLORIDE FORMED IN A CONVERSION OF HYDROCARBONS IN THE PRESENCE OF ALUMINUM CHLORIDE CATALYST, WHILE MINIMIZING CORROSION OF EQUIPMENT, WHICH COMPRISES FLOWING SAID LIQUID COMPLEX DOWNWARDLY THROUGH A VERTICAL BAFFLED CONTACT TOWER HAVING A CONTACTING INNER SURFACE OF NICKEL-CONTAINING ALLOY RESISTANT TO CORROSION BY SAID LIQUID COMPLEX COUNTERCURRENTLY TO A RISING STREAM OF HOT INERT GAS AT TEMPERATURES AND FLOW RATES SUCH AS TO EFFECT VAPORIZATION AND REMOVAL OF ALUMINUM CHLORIDE AND HYDROGEN CHLORIDE TO AN EXTENT SUFFICIENT TO SUBSTANTIALLY REDUCE THE CORROSIVITY OF THE RESIDUAL COMPLEX TOWARD LOW-CARBON STEEL BUT INSUFFICIENT TO CAUSE SOLIDIFICATION OF SAID RESIDUAL COMPLEX, WITHDRAWING GAS ENRICHED WITH ALUMINUM CHLORIDE AND HYDROGEN CHLORIDE FROM A HIGH POINT IN SAID TOWER, WITHDRAWING LIQUID NON-CORROSIVE RESIDUAL COMPLEX FROM A LOW POINT POINT IN SAID TOWER AND PASSING SAME INTO A COKING VESSEL HAVING AN INNER SURFACE OF ORDINARY LOW-CARBON STEEL, HEATING SAID COKING VESSEL SUFFICIENTLY TO LIBERATE FURTHER AMOUNTS OF ALUMINUM CHLORIDE FROM SAID RESIDUAL COMPLEX AND REDUCE SAME TO A SOLID, INTRODUCING A HOT INERT GAS INTO SAID COKING VESSEL AS CARRIER FOR VAPORIZED ALUMINUM CHLORIDE, PASSING A PORTION OF SAID HOT GAS FROM SAID COKING VESSEL INTO SAID TOWER AT A LOW POINT THEREIN FOR UPWARD FLOW THERETHROUGH, WITHDAWING FROM SAID COKING VESSEL THE REMAINDER OF SAID HOT GAS CARRYING ALUMINUM CHLORIDE VAPORS LIBERATED IN SAID COKING VESSEL, AND RECOVERING ANHYDROUS ALUMINUM CHLORIDE FROM GASES WITHDRAWN FROM SAID COKING VESSEL AND FROM SAID TOWER AS AFORESAID.