Method for reducing polycyclic aromatic hydrocarbon in diesel oil

Abstract

The invention discloses a method for reducing polycyclic aromatic hydrocarbon in diesel oil. The method comprises the following steps: a gas-phase component obtained after flash evaporation of a diesel oil raw material enters a first hydrogenation reaction zone for a hydrogenation reaction; a liquid-phase component after flash evaporation enters a second hydrogenation reaction zone for hydrodesulfurization and denitrification reaction, an effluent of the second hydrogenation reaction zone downwards enters a third hydrogenation reaction zone for polycyclic aromatic hydrocarbon hydrogenation saturation reaction, and a product of the third hydrogenation reaction zone is discharged from the bottom of the reactor; the second hydrogenation reaction zone is filled with a semi-sulfurized bulk phase hydrogenation catalyst, and the catalyst comprises a VIB group metal sulfide, a VIII group metal oxide, Al2O3 and an auxiliary agent; based on the weight of the bulk-phase hydrofining catalyst, the content of the VIB-group metal sulfide is 40-70%, and the content of the VIII-group metal oxide is 3-25%. According to the method, the high-quality diesel blending component with ultralow sulfur and low polycyclic aromatic hydrocarbon content is produced by taking inferior diesel mixed oil as a raw material under the conditions of simple process, low energy consumption and low cost through the matching of the catalyst and the process flow.

Description

technical field [0001] The invention belongs to the field of clean oil refining, and in particular relates to a method 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] CN 102465021B discloses a diesel combined hydrogenation process. The method is to first cut the diesel raw material into light and heavy components, the light components enter the liqui...

AI Technical Summary

Problems solved by technology

In the method of the invention, most of the sulfur-containing compounds in the raw oil are removed in the gas-phase circulating hydrogenation reactor, and the macromolecular sulfur-containing compounds and polycyclic aromatic hydrocarbons that are difficult to remove are in the liquid-phase circulating hydrogenation reactor. For removal, the invention uses a conventional hydrogenation catalyst. To remove these difficult-to-remove macromolecular sulfur-containing compounds and polycyclic aromatic hydrocarbons, it is necessary to increase the reaction temperature and increase the hydrogen partial pressure, and the hydrogen sulfide produced by the reaction It will also inhibit the hydrogenation removal of macromolecular sulfides and polycyclic aromatic hydrocarbons. In order to achieve qualified diesel products, multiple liquid phase cycles are required, which will increase the energy consumption and operating costs of the device.

Images