Toluene disproportionation process for producing high-purity benzene

A toluene disproportionation, high-purity technology, applied in the production of bulk chemicals, organic chemistry, hydrocarbons, etc., can solve the problems of low purity of benzene products, strict composition restrictions, and many side reactions.

Active Publication Date: 2012-12-12
SINOPEC YANGZI PETROCHEM +1
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0006] The technical problem to be solved by the present invention is to overcome the technical problems of low purity of benzene product when processing toluene in the prior art, strict restrictions on the composition of reaction materials in the disproportionation process, unstable reaction activity and many side reactions in the disproportionation process of toluene, and provide A new toluene disproportionation process for producing high-purity benzene

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  • Toluene disproportionation process for producing high-purity benzene
  • Toluene disproportionation process for producing high-purity benzene

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Experimental program
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Effect test

Embodiment 1

[0014] Composition (by weight percentage) is to contain toluene 90%, non-aromatic 2%, benzene 1.0%, xylene 7%, the raw material of water content 400ppm all enters the rectification system to remove non-aromatic, benzene, xylene and other impurities, after purification The raw material composition (by weight percentage) is containing 99% of toluene, 0.5% of non-aromatic, 0.5% of xylene, and 150ppm of water. The purified raw material is mixed with circulating hydrogen, heated and then fed into the reactor, where it is contacted with a catalyst containing ZSM-5 molecular sieve for toluene disproportionation reaction. Reaction temperature 360°C, pressure 3.2MPa, hydrogen / aromatic molar ratio 2.8, space velocity 5.0h -1 , the weight concentrations of benzene, toluene and xylene in the obtained liquid product were 20.5%, 50.0% and 26.8% respectively, and the freezing point of the benzene product was 5.46°C. After 300 hours of reaction, the weight concentrations of benzene, toluene,...

Embodiment 2

[0018] The composition (by weight percentage) is to contain 90.0% toluene, 2.0% non-aromatic, 8.0% xylene, and 450ppm water content. The raw material first enters the rectification system to remove impurities such as non-aromatic and xylene. %, non-aromatic 0.5%, xylene 0.5%, water 100ppm. The purified raw material and circulating hydrogen are heated and then enter the reactor, and contact with the catalyst containing ZSM-5 molecular sieve to carry out the toluene shape-selective disproportionation reaction. Reaction temperature 430°C, pressure 1.6MPa, hydrogen / aromatic molar ratio 2.0, space velocity 4.2h -1 , the weight concentrations of benzene, toluene and xylene in the obtained liquid product were 13.0%, 68.9% and 15.6% respectively, and the freezing point of the benzene product was 5.46°C.

Embodiment 3

[0020] Composition (by weight percentage) is that the raw material containing toluene 97.0%, non-aromatic 0.9%, benzene 0.7%, xylene 1.4%, water 400ppm enters the rectification system, removes non-aromatic, benzene, xylene and other impurities, and the purified The raw material is composed of 98.5% toluene, 0.5% non-aromatic, 1.0% xylene and 150ppm water. The purified raw material and circulating hydrogen are heated and then enter the reactor, and contact with the catalyst containing ZSM-5 molecular sieve to carry out the toluene shape-selective disproportionation reaction. Reaction temperature 450°C, pressure 2.8MPa, hydrogen / aromatic molar ratio 2.8, space velocity 4.2h -1 , the liquid product composition (by weight percentage) that different reaction time obtains is shown in Table 1, and the freezing point of benzene product is 5.46 ℃.

[0021] Table 1 Toluene shape-selective disproportionation reaction change composition table with time

[0022]

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Abstract

The invention relates to a toluene disproportionation process for producing high-purity benzene. The process comprises the following steps that: (1) a raw material containing more than 90 percent of toluene counted in percentage by weight enters a rectification system for removing impurities in order to improve the concentration of the toluene as the raw material (counted in percentage by weight)to more than 97 percent; and the water content is less than 300 ppm; and (2) the purified raw material passes through a reactor of a fixed bed and is contacted with a catalyst for reaction to obtain benzene and xylene under the condition of critical hydrogen; the reaction temperature is between 300 and 500 DEG C; the reaction pressure is between 0.5 and 5.0 MPa; the weight space velocity of the raw material is between 0.1 and 15.0 hours<-1>; and the molar ratio of hydrogen to toluene is 0.2-10.0:1. The process solves the technical problems that a benzene product has low purity; the disproportionation process strictly limits the combination of the reaction material and has instable reaction activity and more sub-reaction when the toluene is processed in the prior art.

Description

technical field [0001] The invention relates to a toluene disproportionation process for producing high-purity benzene. Background technique [0002] Toluene disproportionation (including toluene shape-selective disproportionation) is an important unit in the production of aromatics, and is the main method for industrial production of benzene and xylene. The usual toluene disproportionation process adopts the process that the toluene-containing raw material directly enters the reactor for reaction. The raw material buffer tank in the advanced process of toluene raw material is mixed with circulating toluene and then mixed with hydrogen, and then heated and then contacted with the catalyst in the reactor for reaction; the reacted material is cooled and separated into gas phase and liquid phase. The liquid phase enters the subsequent rectification system to separate non-aromatic, benzene, toluene, xylene and other products, and the unreacted toluene is recycled back to the re...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C15/08C07C15/04C07C6/12
CPCY02P20/52
Inventor 张赛军孔德金朱兵李为夏中才杨卫胜李旭灿
Owner SINOPEC YANGZI PETROCHEM
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