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C8 Aromatics Isomerization-Separation Coupling Reaction Method

A technology for isomerization and coupling reaction of aromatic hydrocarbons, which is applied in the field of isomerization of alkyl aromatic hydrocarbons, and can solve problems such as xylene loss

Active Publication Date: 2019-06-14
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method results in the loss of xylene in the isomerization reaction due to the occurrence of non-target acid-catalyzed transalkylation reactions and cyclocracking reactions

Method used

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  • C8 Aromatics Isomerization-Separation Coupling Reaction Method
  • C8 Aromatics Isomerization-Separation Coupling Reaction Method
  • C8 Aromatics Isomerization-Separation Coupling Reaction Method

Examples

Experimental program
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preparation example Construction

[0036] The preparation method of the phosphorus-modified hydrogen-type molecular sieve of the invention comprises: impregnating the hydrogen-type molecular sieve with a phosphorus-containing compound solution dissolved in water. The impregnation pressure is preferably 0.1-1.0 MPa, the impregnation temperature is preferably 75-180°C, the liquid / solid volume ratio of the impregnation liquid to the molecular sieve is 0.7-3.0, and the impregnation time is preferably 5-24 hours. The solid obtained after impregnation is dried and calcined to obtain phosphorus-modified molecular sieves. The phosphorus-containing compound used for impregnation is selected from one or more of ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, aluminum phosphate, phosphoric anhydride, phosphorous acid, ammonium phosphite and phosphoric acid.

[0037] In the above process of preparing phosphorus-modified molecular sieves, the drying temperature is 80-130°C, preferably 100-1...

example 1

[0050] Get 200 grams of silica / alumina mol ratio as 90, crystallinity is 85% HZSM-5 molecular sieve, 150 grams of silica / alumina mol ratio is 550, crystallinity is 76% NaZSM-5 and 50 grams of alumina Mix well, add nitric acid aqueous solution with a mass concentration of 4% by mass according to the ratio of solid / liquid mass ratio 3:1, extrude into strips, dry the strips at 120°C for 6 hours, pelletize, and roast at 550°C for 5 hours. Catalyst A-1 was prepared, which contained 50% by mass of HZSM-5 molecular sieve, 37.5% by mass of NaZSM-5 molecular sieve and 12.5% ​​by mass of alumina.

example 2

[0052] Prepare catalyst by the method for example 1, difference is that 280 grams of HZSM-5 molecular sieves, 100 grams of NaZSM-5 molecular sieves and 20 grams of aluminum oxide are mixed, and catalyst A-2 is obtained through extruding, drying, roasting, wherein contains 70 mass % of HZSM-5 molecular sieve, 25% by mass of NaZSM-5 and 5% by mass of alumina.

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Abstract

The invention relates to a C8 aromatic isomerization-separation coupling reaction method. The method comprises the following steps of enabling gaseous C8 arene to be led into an isomerization catalyst bed, performing an aromatic isomerization reaction under the condition of 170-400 DEG C and 0.2-2.0MPa, and then desorbing reaction materials, wherein the isomerization catalyst comprises 20-70 % by mass of a hydrogen type molecular sieve, 20-55% by mass of a molecular sieve free of isomerization activity and having a ten-membered ring pore channel structure, and 5-60% by mass of aluminum oxide or silicon dioxide, and the hydrogen type molecular sieve is selected from at least one of MFI, MEL, EUO, MOR and UFI ; and the molecular sieve having the ten-membered ring pore channel structure is selected from at least one of MFI, MEL and MWW structural molecular sieves. According to the method, the isomerization reaction is coupled with separation, so that paraxylene of which the PX content exceeds a thermodynamic equilibrium value can be obtained.

Description

technical field [0001] The present invention relates to a kind of alkyl aromatic hydrocarbon isomerization method, specifically, a kind of C 8 Aromatics Isomerization-Separation Coupled Reaction Approach. Background technique [0002] C 8 Aromatics usually come from catalytic reforming, steam cracking and toluene disproportionation units, among which p-xylene (PX) is an important chemical raw material, mainly used to produce purified terephthalic acid (PTA), dimethyl terephthalate ( DMT), but also raw materials for the production of paints, dyes, pesticides and pharmaceuticals. px in various sources of C 8 The content of aromatics generally does not exceed 25%. In order to meet the growing demand, industrially use simulated moving bed adsorption separation or crystallization technology to separate mixed C 8 PX and OX in aromatics can be separated by rectification, and the remaining stream is converted into a mixture whose PX content is close to or reaches the thermodynam...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C15/08C07C5/27C07C7/00C07C7/13B01J29/40B01J29/80B01J29/44B01J29/82
CPCY02P20/52
Inventor 苑志伟刘宇兴王德华郁灼王辉国
Owner CHINA PETROLEUM & CHEM CORP