the heat exchanger 108 effluent to provide supplemental cooling the quenched heat exchanger effluent 120 is then passed into at least one tar knock out drum 122 where the effluent is separated into a bottoms tar and coke fraction 124 and a gaseous fraction 126 the bottoms fraction can be cooled in a heat exchanger 123 to produce a cooled tar stream 125 the tar knock out drum gaseous fraction 126 passes through one or more cracked gas coolers 128 where the fraction is cooled to a temperature ranging from about 121 u00b0 to about 204 u00b0 c 250 u00b0 to 400 u00b0 f such as from about 135 u00b0 to 177 u00b0 c 275 u00b0 to 350 u00b0 f e g 149 u00b0 c 300 u00b0 f by indirect heat transfer e g with deaerated boiler feed water as the cooling medium gas coolers may also be used to raise medium pressure steam or low pressure steam the cooled effluent 130 is then introduced to rectifier 132 at a level below the distillation plates or stages 134 the rectifier distills pyrolysis gasoline from heavier hydrocarbons using low level heat present in the effluent stream the heavier hydrocarbons are taken as bottoms via line 136 which can be used at least in part as quench oil the largely c 10 and lighter overhead taken via line 138 comprising pyrolysis.