Patent ID: 8524070

Claim:
A method for treating gaseous effluent from a hydrocarbon pyrolysis unit, the method comprising: (a) cooling said gaseous effluent at least to a temperature at which tar, formed by reaction among constituents of the gaseous effluent, condenses; (b) passing a mixed gaseous and liquid effluent from step (a) through at least one vapor-liquid separator, where the condensed tar separates from the gaseous effluent and the condensed tar is removed from the method as separator bottoms; (c) cooling the tar-depleted gaseous effluent from step (b) in one or more cracked gas coolers to condense a liquid effluent quench oil; (d) passing at least a portion of the effluent from step (c) containing liquid effluent quench oil through at least one rectifier comprising a fixed number of distillation stages ranging from about 2 to about 20 and/or equivalent suitable packing and comprising a reflux inlet for introducing a pyrolysis gasoline fraction, and further, obtaining liquid effluent quench oil as rectifier bottoms; (e) cooling the gaseous effluent from step (d) to condense a liquid effluent comprising pyrolysis gasoline and water condensed from steam; (f) treating a mixed gaseous and liquid effluent from step (e) to at least partially separate therefrom a liquid pyrolysis gasoline rich stream; and (g) passing at least a portion of the liquid pyrolysis gasoline rich stream as reflux to said rectifier.