Method of converting ethylbenzene and process for producing p-xylene

Abstract

A method by which ethylbenzene contained in a C8-aromatic-hydrocarbon mixture containing a nonaromatic hydrocarbon in a large amount is converted mainly to benzene. The method is reduced in xylene loss, can reduce the rate of catalytic-activity deterioration, and can attain a high conversion into p-xylene. The method of ethylbenzene conversion comprises bringing a feed material comprising an alicyclic hydrocarbon, which is contained in an amount of 1.0 wt.% or larger, ethylbenzene, and xylene into contact with hydrogen in the presence of a catalyst to convert the ethylbenzene contained in thefeed material mainly into benzene. The catalyst is a catalyst constituted mainly of zeolite MFI and an inorganic oxide and having rhenium deposited thereon. The conversion is conducted at a reaction pressure of 1.0 MPa -G or higher.

Description

technical field [0001] The invention relates to a conversion method of ethylbenzene and a production method of p-xylene. More specifically, it relates to a method for mainly converting ethylbenzene in a feed material containing at least 1.0% by weight or more of alicyclic hydrocarbons, ethylbenzene and xylene into benzene, which can reduce the loss of xylene and suppress catalytic activity degradation, and can achieve a higher conversion rate of p-xylene, and involves the product obtained from the conversion to distill and purify the C8 aromatic hydrocarbon mixture, and then separate the p-xylene method. Background technique [0002] Among the xylene isomers, the industrially most important raw material is p-xylene. Para-xylene is used as a monomer for polyester, which is the main polymer currently on par with nylon, and as a raw material for terephthalic acid. In recent years, para-xylene has been in high demand in Asia and other regions, and this trend is expected to cont...

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Problems solved by technology

[0027] These methods are all the same as the isomerization reaction of the "separation-isomerization cycle" in terms of converting ethylbenzene into benzene and ethane by dealkylation reaction, but in the case of using the former, since the feed material is not The C8 aromatic hydrocarbons circulated in the "separation-isomerization cycle" are diluted, so especially when pyrolysis gasoline containing a large amount of non-aromatic hydrocarbons is used as the feed material, the amount of xylene loss is extremely increased, and the deterioration rate of the catalyst is also reduced. In the case of using the latter, although the feed material is diluted by the C8 aromatic hydrocarbons circulating in the "separation-isomerization cycle", the feed amount of the feed material to the xylene isomerization process increases, so there is even There is a slight deterioration in the loss of xylene, which has a greater impact on the unit consumption of raw materials.

That is, in the case of using pyrolysis gasoline containing a large amount of non-aromatic hydrocarbons, if the prior art is used, the degradation rate of the catalyst will increase rapidly, and the loss of xylene will also increase, so there will be a significant change in catalyst life and raw material consumption Therefore, these methods cannot be used in the case of using a large amount of pyrolysis gasoline, etc. that contain ethylbenzene and want to reduce the amount of ethylbenzene recycled in the "separation-isomerization cycle"

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