Patent ID: 8118996

Claim:
A process for quenching hot cracked hydrocarbonaceous effluent that comprises: a) introducing hot cracked hydrocarbonaceous effluent to a quench header; b) introducing a pre-quenching oil containing crackable C5+ components to the quench header through a pre-quenching oil inlet for mixing with the hot cracked hydrocarbonaceous effluent, under conditions sufficient to substantially crack the crackable components in a cracking zone downstream of the pre-quenching oil inlet wherein the pre-quenching oil is a 538° C. + fraction containing from about 10 to about 80 wt % aromatics, from about 2 to about 3 wt % asphaltenes, from about 0.1 to about 5 wt % sulfur, and from about 0 to about 30 wt % paraffins and wherein the pre-quenching oil inlet and the primary quenching oil inlet are separated to an extent sufficient to provide a process gas residence time ranging from about 0.04 to about 0.09 seconds for the cracked effluent and pre-quenching oil at a process gas flow rate between about 100 and about 300 feet/second; and c) introducing a quenching oil to the quench header through a primary quenching oil inlet downstream of the cracking zone to substantially terminate further cracking in the effluent of the cracking zone and provide a quenched effluent.