Effect of multistage hydroprocessing on aromatic and nitrogen compositions of shale oil

Geokinetics crude shale oil, a distillate and processing intermediates sampled during four-stage catalytic hydroprocessing of the distillate were analysed for total nitrogen, basic nitrogen and olefinic and aromatic contents. Successive hydroprocessing stages yielded products containing 80, 46, 16 and 2% of the nitrogen content in the feedstock. Total nitrogen, basic nitrogen and aromatic contents were also reduced. Apparent relative reactivities of aromatic hydrocarbons and nitrogen-containing compounds are in agreement with reactivities observed in model compound studies. Hydrodenitrogenation of nitrogen-containing compounds occurred concurrently with hydrogenation of non-nitrogen-containing aromatic hydrocarbons. Hydroprocessing conditions necessary for essentially complete removal of nitrogen yielded a refined oil with low aromatic content.