关键词: 重油, 加氢, 氮化物结构, 量子化学, 催化剂

Abstract:

The molecular structures of nitrogen compounds change regularly with the increase of oil distillation range. The relationship between the molecular structure of the nitrogen compounds and the hydrogenation behavior is an important guiding theory for the design of hydrodenitrogenation (HDN) catalysts. This study used theoretical calculation to investigate the variation in the properties and reaction behaviors of basic and non-basic nitrogen compounds with their structures. The results showed that the adsorption strength and charge transfer increased with the number of aromatic rings on the nitrogen compounds. In addition, the horizontal adsorption gradually became the dominated morphology instead of vertical adsorption. As the number of aromatic rings increased, it became more difficult to break C—N bonds through a low activation energy pathway. Instead, the bonds could only be broken through the substitution pathway with a high activation energy. Therefore, the break of the C—N bond required the saturation of the aromatic rings through full hydrogenation. The major nitrogen compounds in the products of the high hydrogenolysis capacity catalyst were polycyclic aromatics, whereas those of the catalyst with high hydrogenation saturation capacity contained more compounds with double aromatic rings. The results of hydrogenation experiments indicated that the catalyst with high hydrogenolysis ability offered higher HDN activities for the light distillate, whereas the catalyst with high hydrogenation ability performed better for the heavy distillate.

Key words: heavy oil, hydrogenation, structure of nitrogen compounds, quantum chemistry, catalyst