Analysis of the thermal hydrocracking of heavy fuel oil

The thermal hydrocracking of Mexican heavy fuel oil was studied at 1200 psia and different reaction temperatures (370, 380, 390 and 400°C). The results show that the vacuum residue which constitutes 62 wt. % of the heavy fuel oil and contains 47 wt. % resins and 23.3 wt. % asphaltenes, reacts to form lighter hydrocarbons (IBP-540°C), solid and gas. Resins transform more easily to saturates, and gases are produced mainly from the asphaltene fraction, indicating that the terminal alkyl groups in this fraction are shorter than those present in the resin fraction. The C-C scission reactions dominate the transformation of heavy fuel oil in the interval from 370 to 390°C, whereas the carbon rejection reactions are dominant at 400°C. Finally, the thermal hydrocracking of heavy fuel oil at 390°C appears suitable since at this temperature the reaction produces the greater amount of atmospheric distillates (+20.5 wt. %) and a low content of solid (2.0 wt. %) and gas (2.1 wt. %).