Fluid Catalytic Cracking of Alberta Tar Sand Bitumen

Fluid catalytic cracking (FCC) is currently being studied as a method to produce premium value gasoline from petroleum gas oil. In the present investigation, the effect of prehydrotreatment of heavy vacuum gas oil (VGO) of the atmospheric distillation residue (feed material) from Athabasca tar sand bitumen on the yields of light and middle fractions during FCC is reported. Also, the behavior of coke formation during FCC of VGO is examined. Hydrotreatment of feed material was done in a 500-mL autoclave using Ni-Mo/Al₂O₃ catalyst at 390 and 420 °C under an initial hydrogen pressure of 85 kg/cm² (gauge) with a reaction time of 90 min. The FCC of VGO from the hydrotreated and nontreated feed material was done in a small apparatus at 482 °C with WHSV of 16 wt/wt/h under atmospheric pressure of nitrogen. FCC of the VGO from the hydrotreated feed material yielded a drastic increase of naphtha fraction to 43 wt % and decreased the heavy fraction to 16 wt %. It suggested that, for existing refineries, installation of a mild hydrotreating unit upstream of a FCC may provide an economical increase of yield and quality of useful distillates. The effect of vacuum residue (VR) in the feed material on the reactivity in catalytic cracking was also investigated.