Residues (petroleum), coker scrubber, Condensed-ring-arom.-contg.; Heavy Fuel oil; [A very complex combination of hydrocarbons produced as the residual fraction from the distillation of vaccum residuum and the products from a thermal cracking process. It consists predominantly of hydrocarbons having carbon numbers predominantly greater than C20 and boiling above approximately 350 °C (662 °F). This stream is likely to contain 5 wt.% or more of 4- to 6-membered condensed rind aromatic hydrocarbons.]