Abstract: The properties of diesels from different sources and the hydrogenated products were analyzed in detail, and the relationship between hydrocarbon composition and color of hydrotreated diesel with narrow distillation range was investigated. The influence of process conditions on the color materials of hydrotreated diesel was researched in a medium scale test unit. The results show that the color materials in the diesel fractions are mainly concentrated in the heavier fractions, and the main color materials in hydrotreated diesel are pyrene and fluoranthrene. By increasing hydrogen partial pressure or hydrogen-oil ratio, the hydrogenation equilibrium of PAHs can be broken, resulting in the product of light color.

Key words: hydrotreated diesel, polyaromatic hydrocarbons, color, hydrogenation saturation