Effect of cyclohexane as hydrogen-donor in ultradispersed catalytic upgrading of heavy oil

In order to improve liquid yield while suppressing coke formation, the effect of cyclohexane as hydrogen-donor solvent was studied in a stirred batch reactor (100 mL) at temperature 425 oC, initial pressure 17.5 bar, agitation 500 rpm, and a short reaction time of 10 minutes. The use of cyclohexane was evaluated against that of hydrogen gas. The reaction under hydrogen atmosphere significantly reduced coke yield by 41.3 % compared with a nitrogen environment under the same conditions.

Also, the coke decreased by 6.2-45.4 % as the cyclohexane:oil ratio increased from 0.01 to 0.08 (g.g-1) relative to 4.67 wt.% of coke observed without added cyclohexane in ultradispersed catalytic upgrading under nitrogen environment. As the cyclohexane:oil ratio increases, the produced oil API gravity and middle distillate fractions (200 – 343 oC) increases while the viscosity decreases. An estimated - 0.073 CH:oil ratio was found to suppress coke formation in a similar manner to upgrading under hydrogen atmosphere at the same conditions.