Method for producing paraxylene by using multistage suspension crystallization process

A p-xylene and suspension crystallization technology, applied in crystallization purification/separation, organic chemistry, etc., can solve the problems of unstable product quality and output, difficult crystal washing, high energy consumption, etc., and achieve consistent output, good technical effect, The effect of high energy consumption

Active Publication Date: 2015-04-29
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The technical problem to be solved by the present invention is the problems of large energy consumption, difficult crystal washing, unstable product quality and yield in the existing p-xylene crystallization production, and a novel method for producing p-xylene by multi-stage suspension crystallization is provided

Method used

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  • Method for producing paraxylene by using multistage suspension crystallization process
  • Method for producing paraxylene by using multistage suspension crystallization process
  • Method for producing paraxylene by using multistage suspension crystallization process

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Embodiment 1

[0020] The invention relates to a crystallization method for producing p-xylene by multistage suspension crystallization.

[0021] Such as figure 1 Said, mixed xylene raw material 1, the temperature is 50 ℃, the content of p-xylene is 94wt%, the flow rate is 78249kg / h, after being cooled to 20 ℃ by mother liquor heat exchanger A and precooler B, it enters primary crystallizer C The crystallization temperature is 4°C; the crystal slurry 2 in the primary crystallizer is separated by the solid-liquid separator D to obtain p-xylene crystals 3 and the primary crystallization mother liquor 4, and the p-xylene crystals 3 are separated in the solid-liquid separator D After being washed by the washing liquid 19, it enters the melting tank E, and the primary crystallization mother liquor 4 is divided into three shares, and the first-stage crystallization mother liquor 5 accounting for 80% by weight returns to the primary crystallizer C, and the second share accounts for 10% by weight T...

Embodiment 2

[0024] The invention relates to a crystallization method for producing p-xylene by multistage suspension crystallization.

[0025] According to the operating condition of embodiment 1, adopt as figure 1 In the crystallization method for producing p-xylene by multi-stage suspension crystallization, the operating temperature of the magma tank is 5.5°C.

[0026]

Embodiment 3

[0028] The invention relates to a crystallization method for producing p-xylene by multistage suspension crystallization.

[0029] According to the operating condition of embodiment 1, adopt as figure 1 In the crystallization method for producing p-xylene by multi-stage suspension crystallization, the operating temperature of the magma tank is 6°C.

[0030]

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Abstract

The invention relates to a method for producing dimethylbenzene by using a multistage suspension crystallization process, mainly solving the problems that the energy consumption is high, crystals are hard to wash, and products are unstable in quality and yield in the prior art. The method comprises the following steps: separating out partial dimethylbenzene products through a high-temperature primary crystallization process; separating out the residual paraxylene by using a secondary crystallization process; collecting crystals in the secondary crystallization process by using a crystal slurry tank with a thickening function; carrying out pulpifying washing and heating aging on the low-temperature crystals prepared by the temperature secondary crystallization process by using a high-temperature primary crystallization mother liquid so that the purity of the product is ensured, thereby obtaining the residual paraxylene products; and thickening the crystal slurry in the bottom of the crystal slurry tank and then introducing thickened crystal slurry into a solid-liquid separator to be separated. The method can be applied to production of paraxylene crystals.

Description

technical field [0001] The invention relates to a method for producing p-xylene by multistage suspension crystallization. Background technique [0002] Paraxylene (PX) is an important organic chemical raw material, mainly used as a raw material for the production of purified terephthalic acid (PTA) and dimethyl terephthalate (DMT), and PTA is used to produce polyethylene terephthalate Polyester products such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). At present, China has become the world's largest producer of PX, with total output accounting for more than 10% of the global output. By the end of 2011, my country had 13 sets of PX production facilities with a total production capacity of 8.11 million t / a. In recent years, my country's polyester industry has continued to develop at a high speed. Driven by the polyester industry, domestic PTA production capacity has also expanded rapidly. PX supply is far from meeting the demand for PTA productio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C15/08C07C7/14
Inventor 陈亮宗弘元郭艳姿张鸿翔
Owner CHINA PETROLEUM & CHEM CORP
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