Thermal cracking of hydrocarbons

Claim 1

IN A PROCES WHEREIN MIXED NAPHTHA FEED IS THERMALLY CRACKED AT A TEMPERATURE ABOVE ABOUT 1200*F. IN A CRACKING ZONE IN THE PRESENCE OF 70 TO 80 MOL PERCENT STEAM TO PRODUCE UNSATURATED NORMALLY GASEOUS HYDROCARBONS AND LIQUID AROMATIC, OLEFINIC A ND DIOLEFINIC HYDROCARBONS, THE IMPROVEMENT WHICH COMPRISES QUENCHING THE CRACKED PRODUCTS TO A TEMPERATURE BELOW ABOUT 700*F. BY INJECTING INTO THE CRACKED PRODUCTS LEAVING SAID CRACKING ZONE A QUENCHING MEDIUM CONSISTING ESSENTIALLY OF A HIGH BOILING AROMATIC REFRACTORY CONCENTRATE A PORTION OF WHICH REMAINS IN LIQUID FORM DURING AND AFTER THE QUENCHING STEP, SAID AROMATIC CONCENTRATE BEING MADE BY TREATING A MIXTURE WHICH CONTAINS 40-60% BY VOLUME OF HEAVY CATALYTIC CYCLE OIL WHICH BOILS ABOVE ABOUT 530*F. AND THE REST HEAVY VIRGIN GAS OIL WHICH BOILS ABOVE ABOUT 655*F. WITH A PHENOL-CONTAINING LIQUID TO OBTAIN A PHENOL EXTRACT AND RECOVERING THE AROMATIC CONCENTRATED FROM THE PHENOL EXTRACT PHASE, SAID PHENOL-CONTAINING LIQUID COMPRISING A PHENOL EXTRACT OBTAINED WHEN TREATING LUBRICATING OIL IN A LIQUID-LIQUID EXTRACTION STEP.