Method for aromatic co-production

Abstract

The invention relates to a method for aromatic co-production and mainly solves the problems of low concentration of paraxylene, high treatment and circulation amount of aromatics, strict requirements and energy consumption of reaction raw materials and the like in the mixed dimethylbenzene during paraxylene production in the prior art. Mixed raw materials from a reforming unit are separated; C9, aromatics with over 9 carbon atoms, and methylbenzene enter a disproportionated and alkyl transfer process unit of the methylbenzene, the C9 and the aromatics with over 9 carbon atoms for a dealkylation reaction to generate a second strand of benzene, a second strand of methylbenzene and a second strand of C8 aromatics; the methylbenzene enters a methylbenzene selective disproportionated process unit for a methylbenzene selective disproportionated reaction to generate the C8 aromatics and a benzene mixture flow which contains the paraxylene to obtain third strand C8 aromatics, a third strand of methylbenzene and a third strand of benzene; low-concentration C8 aromatics are mixed and fed into an adsorption separated unit to obtain the C8 aromatics containing high-concentration paraxylene; and the C8 aromatics containing high-concentration paraxylene are fed into a crystallizing and separating unit to obtain a paraxylene product and a fourth strand of aromatics. With the technical scheme, the invention better solves the problem and can be used for paraxylene industrial production.

Description

technical field The invention relates to a method for co-production of aromatic hydrocarbons. Background technique P-xylene is one of the main basic organic raw materials in the petrochemical industry. It is widely used in many chemical production fields such as chemical fibers, synthetic resins, pesticides, medicines, and plastics. The typical production method of p-xylene is from the thermodynamically balanced xylene containing ethylbenzene, that is, C8 aromatics generated by catalytic reforming of naphtha, through multi-stage cryogenic crystallization separation or molecular sieve simulated moving bed adsorption separation (adsorption separation for short) Technology to separate p-xylene from a mixture of isomers with similar boiling points. For the treatment of ortho- and meta-xylene, C 8 A isomerization (referred to as isomerization) technology to isomerize it into p-xylene. In order to increase the production of p-xylene, the disproportionation of toluene or the dis...

AI Technical Summary

Problems solved by technology

The technical problem to be solved by the present invention is that in the production of p-xylene in the prior art, there are problems such as the low concentration of p-xylene in the mixed xylene, resulting in large circulation of xylene separation unit and isomerization unit, high energy consumption, etc., providing A new production method of p-xylene

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