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Method for preparing paraxylene from methylbenzene mixture

A p-xylene and mixture technology, which is applied in the field of fluidized bed catalysis, can solve problems such as reactor overheating, stability problems, and poor p-xylene selectivity indicators, so as to improve conversion rate, ensure stability, and guarantee Effects of Continuity and Reliability

Inactive Publication Date: 2018-12-28
陕西煤化工技术工程中心有限公司
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0007] In order to improve the conversion rate of raw materials benzene and toluene, avoid the stability problem of the fixed bed catalyst and the generation of partial overheating of the reactor, and at the same time solve the problem of poor conversion rate of aromatics raw materials and selectivity of p-xylene in the existing fluidized bed technology question

Method used

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  • Method for preparing paraxylene from methylbenzene mixture
  • Method for preparing paraxylene from methylbenzene mixture

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Experimental program
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Effect test

Embodiment 1

[0027] The reaction form of two fluidized bed reactors in series is adopted, toluene and water all enter from the first reactor, and methanol is divided into two streams and enters from the entrance of the first and second reactor respectively. Toluene mixtures with mass flow rates of 28.6g / h, 10.5 g / h and 4.0g / h respectively (the mass ratio of benzene to toluene is 3:7), methanol and water enter the first reactor for reaction after being vaporized and mixed. The product is uniformly mixed with the second stream of gas-phase methanol at a mass flow rate of 11.1 g / h, and then enters the second-stage fluidized-bed reactor to continue the reaction. The two reactors are filled with the same type of ZSM-5 molecular sieve catalyst, and the first and second stage reactors have a dense-phase catalyst storage capacity of 10g; the reaction temperature of the two stage reactors is 500 °C, and the first stage reaction The reaction pressure of the reactor is 0.105MPa(G), and the reaction p...

Embodiment 2

[0029] The reaction form of two fluidized bed reactors in series is adopted, toluene and water all enter from the first reactor, and methanol is divided into two streams and enters from the entrance of the first and second reactor respectively. Toluene mixed aromatics with mass flow rates of 28.6g / h, 10.5 g / h and 4.0g / h (mass ratio of benzene to toluene is 3:7), methanol and water enter the first reactor for reaction after being vaporized and mixed. The reaction product is uniformly mixed with the second stream of gas-phase methanol at a mass flow rate of 10.5 g / h, and then enters the second-stage fluidized-bed reactor to continue the reaction. The two reactors are filled with the same type of ZSM-5 molecular sieve catalyst, and the first and second stage reactors have a dense-phase catalyst storage capacity of 10g; the reaction temperature of the two stage reactors is 540 ° C, and the first stage reaction The reaction pressure of the reactor is 0.105MPa(G), and the reaction p...

Embodiment 3

[0031] The reaction form of two fluidized bed reactors in series is adopted, toluene and water all enter from the first reactor, and methanol is divided into two streams and enters from the entrance of the first and second reactor respectively. Toluene mixed aromatics with mass flow rates of 28.6g / h, 10.5 g / h and 4.0g / h (mass ratio of benzene to toluene is 3:7), methanol and water enter the first reactor for reaction after being vaporized and mixed. The reaction product is uniformly mixed with the second stream of gas-phase methanol at a mass flow rate of 10.5 g / h, and then enters the second-stage fluidized-bed reactor to continue the reaction. The two reactors are filled with the same type of ZSM-5 molecular sieve catalyst, and the first and second stage reactors have a dense-phase catalyst storage capacity of 10g; the reaction temperature of the two stage reactors is 480 ° C, and the first stage reaction The reaction pressure of the reactor is 0.105MPa(G), and the reaction p...

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Abstract

The invention relates to a method for preparing paraxylene from benzene, a methylbenzene mixture and methanol alkylation. A mixed arene raw material of the benzene and methylbenzene is mixed with a partially alkylated reagent methanol and a small amount of vapor phase without being subjected to separation purification, and a mixture enters a dense-phase fluidized bed to be in contact and react with a catalyst; after reaction gas is subjected to gas-solution separation and then mixed with the residual methanol gas phase, the mixture enters a downstream dense-phase fluidized bed to be continuously in contact and react with the catalyst, and the conversion rate of the arene raw material and the alkylation rate of methanol are improved; and the carbon deposition catalyst is cyclically regenerated, the arene raw material of the benzene and the methylbenzene, which does not react finally, can be returned to a reaction region in a form of the mixture after being cooled and separated, and generated xylene enters a subsequent paraxylene separation device. The technology is applicable to the industrial production process of preparing the paraxylene by using the benzene and methylbenzene mixture as the arene raw materials through methanol alkylation in an independent built plant or an aromatic combination plant.

Description

technical field [0001] The invention relates to a fluidized bed catalytic technology method for preparing p-xylene from a mixture of benzene, toluene and methanol with high selectivity, which is mainly used in the field of polyester production. Background technique [0002] As a bulk and important basic chemical, p-xylene is mainly used for the production of p-dibenzoic acid, and then for the production of polyester; in addition, it can also be used as a raw material for the production of solvents, medicines, spices, inks and other industries. [0003] At present, in the aromatics complex, the aromatics mixture mainly composed of benzene and toluene is separated after the catalytic reforming product is extracted with aromatics, and the benzene and toluene need to be further separated through the benzene tower. value conversion to produce p-xylene, only toluene can be produced by disproportionation of toluene or transalkylation with C9 aromatic hydrocarbons to produce p-xylen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C15/08C07C2/86
CPCC07C2/864C07C2529/40C07C15/08Y02P20/52Y02P20/584
Inventor 刘弓曹劲松高兴张军民刘建斌
Owner 陕西煤化工技术工程中心有限公司
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