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Combination method for producing p-xylene

A technology of p-xylene and combined method, which is applied in the combined field of producing p-xylene, and can solve the problems of large circulation volume and high energy consumption of xylene separation unit and isomerization unit

Active Publication Date: 2013-06-05
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] The technical problem to be solved by the present invention is that in the prior art, when p-xylene is produced, there is a problem that the p-xylene concentration in the mixed xylene is low, resulting in large circulation volume and high energy consumption of the xylene separation unit and the isomerization unit, Provide a new production method of p-xylene

Method used

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  • Combination method for producing p-xylene
  • Combination method for producing p-xylene
  • Combination method for producing p-xylene

Examples

Experimental program
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Effect test

Embodiment 1

[0026] Separating the mixed raw materials containing benzene, toluene, C8 aromatics, C9 and above aromatics and non-aromatics to obtain C9 and above aromatics, which are used as raw materials, under the condition of hydrogen, in a fixed bed reactor Carry out the investigation of the dealkylation reaction performance of aromatic hydrocarbons with carbon nine and above. Reactor inner diameter mm, length 1000 mm, stainless steel. The catalyst bed is filled both above and below Millimeter glass beads play the role of air distribution and support, and the reactor is filled with 20 grams of β-zeolite catalyst containing 0.05% bismuth. Aromatic raw materials are mixed with hydrogen and then passed through the catalyst bed from top to bottom for C 9 + A dealkylation reaction to generate benzene, toluene and C 8 A, the reaction temperature is 425°C, the pressure is 3.0MPa, and the weight space velocity is 2.0 hours -1 , a hydrogen / hydrocarbon molar ratio of 5.0:1.

[0027] Raw...

Embodiment 2

[0042] The reaction process is as in Example 1. The toluene selective disproportionation reaction product is separated through a selective disproportionation aromatics fractionation unit to obtain mixed xylene, which is used as a raw material for suspension crystallization separation. Suspension crystallizer with a volume of 500 liters, jacketed and agitator, stainless steel, scrubber with a volume of 40 liters, stainless steel. The raw materials are suspended and crystallized in the crystallization, and the crystallized slurry enters the washing tower for solid-liquid separation and product purification.

[0043] The suspension crystallization separation process includes suspension crystallization and washing purification process. The raw material flow rate of suspension crystallization is 200 liters / minute, the raw material temperature is 20 ℃, the crystallization temperature is -5 ℃, the washing liquid flow rate of washing purification is 15 liters / minute, and the washing t...

Embodiment 3

[0047] C in typical reformed depentanized oil 6 A~C 10 + The composition of various hydrocarbon substances is the basic data, and the present invention is investigated according to the appended figure 2The process flow shown shows the production capacity of paraxylene and benzene and the processing scale of each unit. The composition distribution of aromatics sent from a typical reformer and the flow rate of each component used in this example are shown in Table 5.

[0048] Table 5 Composition and flow rate of reformed depentanized oil aromatics

[0049] composition

ben

Tol

C 8 A

C 9 A

C 10 +

∑

Composition, % by weight

14.41

26.79

33.53

24.02

1.25

100.00

Flow rate, kg / h

12673

23560

29482

21122

1095

87932

[0050] where C 10 + It is an aromatic hydrocarbon with ten carbon atoms or more.

[0051] According to attached figure 2 The aromatics flow rate (fresh feed) ...

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Abstract

The invention relates to a combination method for producing p-xylene, which mainly solves the problems of low concentration of p-xylene in mixed xylene, large circulating capacity of processing aromatics, rigorous requirements on reaction raw materials and high energy consumption during the production of the p-xylene in the prior art. In the combination method, a reaction technical scheme that the mixed xylene which contains high-concentration p-xylene and is produced by the selective disproportionation of the methylbenzene and aromatics with 9 and more carbon atoms are subjected to dealkylation reaction to produce combination of benzene, the methylbenzene and the mixed xylene which is in thermodynamic equilibrium, and a separation technical scheme that the high-concentration p-xylene adopts crystallization separation and low-concentration p-xylene adopts combination of adsorption-crystallization separation are adopted to solve the problems better, and the combination method can be used for industrial production of the p-xylene.

Description

technical field [0001] The present invention relates to a combined process for the production of p-xylene. Background technique [0002] 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 (carbon eight aromatics) isomerization (referred to as isomerization) technology to isomerize it into p-xylene. In order to increase the production of p-xylen...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C15/08C07C7/04C07C6/12
Inventor 孔德金钟禄平肖剑李为郭艳姿卢咏琰
Owner CHINA PETROLEUM & CHEM CORP