Study of the Influence Exerted by Addition of Coker Gas Oil to Straight-Run Gas Oil on the Process of Hydrotreating in the Presence of CoMo/Al2O3 Catalyst

Behavior of the CoMo/Al2O3 catalyst was experimentally studied in the course of hydrotreating of a straight-run gas oil with high content of sulfur (>2 wt %) and its mixture (up to 30 wt %) with light coker gas oil in the temperature range 335-365 degrees C and liquid hour space velocity of feedstock deliver of 0.8-2.5 h(-1). It was shown that addition of gas oil to the straight-run gas oil in hydrotreating under the conditions corresponding to the working conditions of the existing domestic hydrotreating installations [L-24-5, L-24-6, L(Ch)-24-7] has oppositely directed effects, depending on temperature and feedstock delivery rate. For example, the additives lead in the temperature range 335-350 degrees C to an increase in the content of sulfur in hydrotreating products. At a temperature of 365 degrees C, better sulfur-related parameters are reached in processing of feedstocks containing light coker gas oil. The observed dependences are accounted for as follows: the dilution of the straight-run gas oil by addition of light coker gas oil leads to a decrease in the content of difficulty converted sulfur-containing compounds, but makes larger the content of nitrogen-containing compounds inhibitors of the hydrodesulfurization reaction, the influence of which on the reaction rate becomes weaker with increasing temperature.