Catalyst grading process for reducing polycyclic aromatic hydrocarbon in diesel oil

Abstract

The invention discloses a catalyst grading process for reducing polycyclic aromatic hydrocarbon in diesel oil, which comprises the following steps: under hydrogenation reaction conditions, a diesel oil raw material sequentially passes through a first catalyst bed layer and a second catalyst bed layer in a fixed bed reactor from top to bottom, and is subjected to hydrogenation reaction with a catalyst of each bed layer and hydrogen from bottom to top, a hydrogenation reaction product flows out from the bottom of the reactor; wherein the first catalyst bed layer is filled with a first hydrogenation catalyst, and the catalyst comprises a hydrogenation catalyst carrier and a hydrogenation active component; the second catalyst bed layer is filled with a second hydrogenation catalyst, the catalyst comprises an alumina carrier and active metal components, and the active components comprise metal state Pt and / or Pd and oxidation state NiO and / or CoO; on the basis of the weight of the catalyst, the active component Pt and / or Pd accounts for 0.3 wt%-8.0 wt%, and the active component NiO and / or CoO accounts for 1 wt%-10 wt%. According to the process, the content of polycyclic aromatic hydrocarbon in the diesel oil raw material can be effectively reduced and high-quality diesel oil can be produced under the conditions of simple process, low energy consumption and low cost through matching of the catalyst and the process flow.

Description

technical field [0001] The invention belongs to the field of clean oil refining, in particular to a catalyst gradation process for reducing polycyclic aromatic hydrocarbons in diesel oil. Background technique [0002] With the demand for diesel quality upgrades, my country's diesel has now completed the quality upgrade of the National VI standard, in which the sulfur content is not more than 10ppm, and the polycyclic aromatic hydrocarbon content is not more than 7%. According to foreign diesel quality standards, the content of polycyclic aromatic hydrocarbons in diesel oil in certain regions of the United States is even lower. It can be seen that further reducing the content of polycyclic aromatic hydrocarbons in diesel oil is an important development direction for diesel quality upgrading. [0003] CN103059983A discloses a hydrorefining catalyst combination packing method. The method of the invention is: after the raw material diesel oil is mixed with hydrogen, it passes t...

AI Technical Summary

Problems solved by technology

The invention uses a mixed catalyst, in which the Mo-Ni type catalyst has high hydrogenation activity, and the raw material oil enters the mixed catalyst, and the hydrodesulfurization and hydrodenitrogenation reactions are carried out on the Mo-Ni type catalyst first, and the Mo-Co type catalyst Can not play a role, it is easy to cause waste of catalyst and increase of volume space velocity; in addition, the mixed catalyst uses an oxidized catalyst, which needs to be vulcanized before use, and the nickel and cobalt in the oxidized catalyst are easy to sulfide, while molybdenum and tungsten are difficult to sulfide , it is easy to cause incomplete vulcanization of molybdenum and tungsten, which affects the activity of the catalyst, and at the same time, the vulcanization process is likely to cause safety problems such as overheating of the device

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