Comparison of Hydrodenitrogenation of Model Basic and Nonbasic Nitrogen Species in a Trickle Bed Reactor Using Commercial NiMo/Al₂O₃ Catalyst

A systematic study has been conducted in a trickle-bed reactor using a commercial NiMo/Al 2 O 3 catalyst to understand the effects of different variables such as H 2 S concentration in the feed by adding different amount of butanethiol, reaction pressure, temperature, liquid hourly space velocity (LHSV), and H 2 /feed ratio on the hydrodenitrogenation (HDN) of typical basic (acridine) and nonbasic (carbazole and 9-ethylcarbazole) nitrogen compounds present in heavy gas oil. The HDN conversion of basic compound was higher than that of nonbasic compounds at all butanethiol concentrations (0−4 wt %) in the feed. The HDN conversion of acridine was 98−99 wt % at 355−400 °C, whereas, with an increase in temperature from 355 to 400 °C, the conversion of carbazole and 9-ethylcarbazole increased somewhat from 92 to 95 wt % and from 94 to 97 wt %, respectively. Pressure (1120−1420 psig) had no effect on the HDN conversion of basic and nonbasic nitrogen compounds. Also, an increase in LHSV did not have a significant effect on the conversion of acridine and 9-ethylcarbazole. However, the conversion of carbazole increased from 92 to 99 wt % with a decrease in LHSV from 2 to 0.5 h - 1 . The increase in H 2 /feed ratio from 200 to 800 mL/mL caused a significant increase in conversion of carbazole from 90 to 98 wt %. The present studies showed no steric hindrance effect of the alkyl group present in 9-ethylcarbazole.