Study On The Transformation Of Nitrogen Compounds In Liaohe Atmospheric Residue During Slurry-bed Hydrocracking

In this paper, group composition and distribution of nitrogen compounds in the Liahe atmospheric residue and in its slurry-bed hydrocracking product were mainly studied. It aimed to identify the transformation regularity of nitrogen compound during the slurry phase hydrocracking and compare the differences between the feed oil and product.The Liahe atmospheric residue and fractions were characterized by FT-ICR MS to find out the main nitrogen compounds in LHAR were N₁ class (e.g., molecules containing the same numbers of N,O and S atoms).With the degreeofunsaturation and boiling point increasing, N₁O₁ and N₁O₂ class gradually appeared. The main nitrogen compounds in light VGO were also N₁ class and their DBE values were between 4 and 15. The N₁ class was still the main nitrogen compound in heavy VGO,but the contents of N₁O₁,N₁O₂ class were increased. The nitrogen compound in LHAR slurry-bed hydrocracking product mainly was N₁ class. The N₁ class which DBE values was between 4 and 15 was distributed all the product fractions. With the boiling point increasing, there was only a small quantity of N2 class in vacuum residuum.Extraction methodology was used to concentrate the basic nitrogen compounds and a column chromatographic method was used to separate the non-basic nitrogen compounds. Making use of FT-IR and GC-MS to found out that with the boiling point increasing the contents of basic nitrogen compounds decreased and the contents of non-basic nitrogen compounds increased. The basic nitrogen compounds were mainly consisted of quinoline. The non-basic nitrogen compounds were mainly consisted of carbazole and amine. Through the distribution of basic and non-basic nitrogen compounds before and after reaction, it indicated that some non-basic nitrogen compounds were turned into basic nitrogen compounds. Some nitrogen compounds were reacted by breaking the side chain or hydrogenation or condensation, so some nitrogen heterocyclic compounds were disappeared and some N₁O₁ class were turned into N₁ class.