Method and device for separating n-hexane, isohexane and benzene

Abstract

The invention relates to a method and a device for separating n-hexane, isohexane and benzene. The device comprises a light component removal unit, an isohexane separation unit, an n-hexane extractive distillation unit, a first solvent recovery unit, a benzene extractive distillation unit, a second solvent recovery unit and a solvent regeneration unit. The method comprises the following steps: removing impurities with a boiling point less than the boiling point of 2-methylpentane in mixed hydrocarbon raw materials such as raffinate oil, pyrolysis gasoline or straight-run gasoline and the like from an aromatics extraction device firstly, and then separating an isohexane product; separating a n-hexane product from other materials by using an extractive distillation method; and removing n-hexane materials, and carrying out separation on the obtained product so as to obtain a benzene product. The main components of the isohexane product produced by using the technique disclosed by the invention are 2-methylpentane and 3-methylpentane, and the total mass fraction of 2-methylpentane and 3-methylpentane is not less than 95%; n-hexane meets the national standard GB16629-2008, and the mass fraction is not less than 99%; and the benzene product meets the national standard GB3405-89.

Description

technical field [0001] The invention relates to a separation method and equipment for n-hexane, isohexane and benzene, in particular to a separation method and equipment combining ordinary rectification and extractive distillation. Background technique [0002] n-Hexane is a colorless transparent liquid, one of the widely used hydrocarbon solvents, and the most representative non-polar solvent. Industrial hexane solvent oil can be used in industries such as medicine, chemical industry, polymer materials, rubber industry and food. As an extractant in the edible oil industry, it is required that the hexane solvent oil fraction should be as narrow as possible, and the benzene content should be as low as possible. These two indicators directly affect the quality, oil yield and energy consumption of edible oil. When n-hexane is used as a solvent for propylene polymerization, the less benzene content is required, the better. This is not only beneficial to increase the rate of po...

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Problems solved by technology

[0006] The method of catalytic hydrogenation to remove benzene in the n-hexane raw material is suitable for the case of low benzene content. When the benzene content is high, the use of this method will not only cause high energy consumption, but also cause waste of benzene resources

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