Hydrodenitrogenation of Taching Atmospheric Residue

Hydrodenitrogenation of Taching atmospheric residue was performed in a fixed bed co-current up-flow reactor packed with a Ni-Mo/Al2O3 catalyst under 50-200kg/cm2 and 360-440°C, and the characteristics of the residue hydrodenitrogenation and effects of sulfur on the reaction were investigated. Nitrogen was found to be considerably poorer than sulfur in reactivity with hydrogen. One of the reasons could be that nitrogen's existence was more localized than sulfur in the heavier fractions. Hydrodenitrogenation of Taching residue was promoted markedly by adding a sulfur compound to the feedstock. This sulfur is assumed to be hydrogenated to hydrogen sulfide that activated the catalyst by keeping it in the sulfided state, and 2% of sulfur in the feedstock seemed adequate. Hydrodenitrogenation was found to be closely related to hydrocracking. The nitrogen removal was linearly correlated with the hydrocracking ratio represented by the decrease in the molecular weight within the range of nitrogen removal above 30%.