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Method for producing p-xylene by multistage suspension crystallization

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

Active Publication Date: 2017-08-25
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 p-xylene by multistage suspension crystallization
  • Method for producing p-xylene by multistage suspension crystallization
  • Method for producing p-xylene by multistage suspension crystallization

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Embodiment 1

[0018] The invention relates to a crystallization method for producing p-xylene by multistage suspension crystallization.

[0019] 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

[0021] The invention relates to a crystallization method for producing p-xylene by multistage suspension crystallization.

[0022] 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.

Embodiment 3

[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 6°C.

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Abstract

The invention relates to a method for producing p-xylene by multi-stage suspension crystallization, which mainly solves the problems of high energy consumption, difficult crystal washing, unstable product quality and output in the prior art. The present invention adopts a two-stage crystallization process, first Part of the p-xylene product is separated through the primary crystallization process at a higher temperature; the remaining p-xylene is separated by the second-stage crystallization process, and the crystals of the secondary crystallization process are collected by a crystal slurry tank with a thickening function. Use the higher-temperature primary crystallization mother liquor to perform slurry washing and heating-up aging on the lower-temperature secondary crystallization crystals to ensure product purity and obtain the remaining p-xylene product; the crystal slurry at the bottom of the crystal slurry tank is thickened The technical scheme of sending it into a solid-liquid separator for separation better solves the problems of high energy consumption, difficult crystal washing, unstable product quality and output in the prior art, and can be used in the production of p-xylene crystallization.

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