Crystallization method for p-xylene production

A technology of p-xylene and mixed xylene, which is applied in the direction of crystallization purification/separation, organic chemistry, etc., can solve the problems of high energy consumption, and achieve the effect of reduced refrigeration energy consumption and good technical effects

Active Publication Date: 2012-03-14
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is the problem of large energy consumption in the exis

Method used

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  • Crystallization method for p-xylene production
  • Crystallization method for p-xylene production
  • Crystallization method for p-xylene production

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The crystallization method of producing p-xylene according to the present invention

[0028] Such as figure 2Said, the mixed xylene 1 contains 90% p-xylene, the flow rate is 14864kg / h, and enters the slurry tank 16 after being cooled by the heat exchanger 2 . The mixed xylenes are crystallized in the first-stage crystallizer 3, and the crystallization temperature is 3°C. The crystal clear mother liquor 22 in the crystallizer 3 flows out from the upper part of the crystallizer and enters the slurry tank 16, and the crystal slurry 4 in the crystallizer 3 is separated from the solid and liquid by the first solid-liquid separator 5 to obtain high-purity p-xylene Crystals 6 and crystallization filter mother liquor 7. P-xylene crystal 6 is melted in melting tank 8, and melting temperature is 20 ℃, and the p-xylene of 20% by weight washes the crystal in the first solid-liquid separator 5 as washing liquid 9, and the p-xylene of 80% by weight Discharged as p-xylene product ...

Embodiment 2

[0030] The crystallization method of producing p-xylene according to the present invention

[0031] use as figure 2 The crystallization method for the production of p-xylene, wherein the weight ratio of crystallization clear mother liquor 22 to crystallization filtration mother liquor 18 is 0.5:1, all the other operating conditions are the same as in Example 1, and the results are listed in Table 1.

Embodiment 3

[0032] Embodiment 3: the crystallization method of producing p-xylene according to the present invention

[0033] use as figure 2 The crystallization method for the production of p-xylene, wherein the weight ratio of crystallization clear mother liquor 22 to crystallization filtration mother liquor 18 is 0.33:1, all the other operating conditions are the same as in Example 1, and the results are listed in Table 1.

[0034] Table 1

[0035]

[0036] [Comparative Example 1]

[0037] Existing crystallization method for producing p-xylene

[0038] use as figure 1 In the crystallization method for producing p-xylene, the operating temperature of the second-stage crystallizer is -3.54° C., and the rest of the operating conditions are the same as in Comparative Example 1. The results are listed in Table 2.

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Abstract

The invention relates to a crystallization method for p-xylene production, and mainly aims to solve the problem of large energy consumption during crystallization separation in existing technologies. According to the method, a slurrying trough is arranged, and a p-xylene crystal obtained from a secondary crystallization process can be slurried so as to enter a first crystallizer, in which a clear mother solution enters the slurrying trough. The technical method of the invention well solves the above problem, and can be used for the industrial production of p-xylene.

Description

technical field [0001] The present invention relates to a crystallization method for producing p-xylene. Background technique [0002] P-xylene is an important raw material for the polyester industry, mainly used to produce purified terephthalic acid (PTA) or purified dimethyl terephthalate (DMT), and then produce polyester (PET) from PTA and DMT, and separate Mixed xylene is the main production method of p-xylene. Mixed xylenes are mainly composed of p-xylene, m-xylene, o-xylene and ethylbenzene. The difference between the boiling points of each component is small, but the difference in melting point is large. The crystallization method can be used to separate p-xylene. [0003] Patent US5448005 discloses a crystallization method for producing p-xylene from a mixed xylene material rich in p-xylene. This method separates high-purity p-xylene products through the first-stage crystallization process, and obtains high-purity p-xylene products through the second-stage crystalli...

Claims

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Application Information

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IPC IPC(8): C07C15/08C07C7/14
Inventor 陈亮肖剑顾军民
Owner CHINA PETROLEUM & CHEM CORP
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