Method for reducing sulfur content in gasoline

Abstract

A method for reducing sulfur content in gasoline comprises the following steps of: (1) contact-reacting a sulfur-containing light fraction gasoline with an ionic liquid at a temperature not less than the boiling point of the sulfur-containing light fraction gasoline and not larger than 200 DEG C, and condensing the gas-phase product to separate the gas-phase product from the liquid-phase product, thus obtaining a light fraction gasoline with reduced sulfur content; and (2) mixing the light fraction gasoline with reduced sulfur content with a sulfur-containing heavy fraction gasoline. The method provided by the invention can, on one hand, reduce the addition level of the ionic liquid and, on the other hand, reduce the yield of liquid-phase product (i.e. the loss of gasoline fraction) on the premise of ensured desulfurization effect. Particularly, most of light fraction gasoline with reduced sulfur content can be obtained without distillation. The gasoline obtained by mixing the light fraction gasoline with reduced sulfur content after contact reaction with the heavy fraction gasoline with reduced sulfur content obtained by hydrodesulfurization has reduced octane number by a magnitude within two octane number units and high desulfurization rate larger than 90% in comparison with the gasoline before desulfurization, so that the gasoline product can meet the EUROIII emission standard of automobile gasoline.

Description

technical field [0001] The invention relates to a gasoline upgrading method, in particular to a method for reducing the sulfur content in gasoline. Background technique [0002] FCC gasoline occupies a dominant position in my country's finished gasoline due to its high octane number. However, due to the relatively high olefin content and sulfur content in this kind of gasoline, generally 15-45% and 500-5000ppm respectively, it cannot meet the new gasoline product standards, such as the equivalent of Euro II issued by Beijing in 2004. Gasoline technical requirement 1 stipulates that the sulfur content is not more than 500ppm, the olefin content is not more than 30%, and the aromatic content is not more than 40% (the benzene content in aromatics is not more than 2.5%). Equivalent to Euro III's Motor Gasoline Technical Requirements 2, when the sulfur content is not greater than 150ppm, the aromatics content is not greater than 35%, and the olefin content is not greater than 25...

AI Technical Summary

Problems solved by technology

Since the temperature of the material has been lowered during the sedimentation and separation of the ionic liquid, it is necessary to reheat the material to not lower than the boiling point of gasoline to distill the gasoline, so a large amount of heat source is consumed

The huge energy consumption makes this simple desulfurization method using ionic liquid alkylation first, then sedimentation to separate the catalyst, and then distillation to obtain gasoline with reduced sulfur content loses its industrial application value

In addition, the above method also needs to use a large amount of ionic liquid, because the cationic part in the ionic liquid is expensive, increasing the production cost is also an obstacle to the industrial application of this alkylation method

Furthermore, since ionic liquids catalyze the alkylation reaction of sulfur-containing compounds such as mercaptans, thioethers, and thiophenes with olefins, olefins in gasoline may also react with other hydrocarbons. , will lead to a significant decrease in gasoline octane number

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