Distillates (petroleum), vacuum; Heavy Fuel oil; [A complex combination of hydrocarbons produced by the vacuum distillation of the residuum from atmospheric distillation of crude oil. It consists of hydrocarbons having numbers predominantly in the range of C15 through C50 and boiling in the range of approximately 270 °C to 600 °C (518 °F to 1112 °F). This stream is likely to contain 5 wt.% or more of 4- to 6-membered condensed ring aromatic hydrocarbons.]