Method for recycling ethylene glycol and acetaldehyde from polyester waste water

A polyester wastewater and ethylene glycol technology, applied in chemical instruments and methods, hydrolysis preparation, water/sewage multi-stage treatment, etc., can solve the problems of increased treatment costs, high equipment requirements, and low concentration of acetaldehyde solution. To achieve the effect of overcoming safety problems, reducing processing technology, and good economic benefits

Active Publication Date: 2011-07-20
SHANGHAI JUYOU CHEM ENG +1
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  • Summary
  • Abstract
  • Description
  • Claims
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Problems solved by technology

This method can obtain high-purity ethylene glycol, but when water is used to directly absorb acetaldehyde vapor, the industrial water is increased and the concentration of the obtained acetaldehyde solution is too low, which requires follow-up treatment, which increases the treatment cost, and the method It is an intermittent method, especially the introduction of the intermittent acid catalytic treatment by-product 2-methyl-1,3-dioxolane, due to the corrosiveness of the acid, the requirements for industrial equipment are very high, and due to the 2-methyl- The formation of acetaldehyde and ethylene glycol from 1,3-dioxolane is a reversible reaction. After the batch treatment, it is difficult to ensure that acetaldehyde and ethylene glycol will not generate 2-methyl-1,3- Dioxolane

Method used

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  • Method for recycling ethylene glycol and acetaldehyde from polyester waste water
  • Method for recycling ethylene glycol and acetaldehyde from polyester waste water
  • Method for recycling ethylene glycol and acetaldehyde from polyester waste water

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Embodiment 1

[0038] The treatment process flow without the addition of a wastewater separation tower will be described.

[0039] The process and device of the present invention have been practically applied in well-known enterprises in the polyester industry. The specific process results are as follows:

[0040] According to the actual production situation, the obtained esterification wastewater was processed through the process flow device provided by the present invention to obtain various product components and their contents, as shown in Table 1.

[0041] Table 1 Esterification wastewater and the content of each component of the product

[0042]

[0043] It can be seen from the results after treatment that after being treated by the stripping tower treatment system of the process flow, the acetaldehyde solution with a purity of more than 99.0% was recovered from the acetaldehyde rectification tower system, and the purity was recovered from the ethylene glycol distillation tower. I...

Embodiment 2

[0045] The treatment process flow of adding a wastewater separation tower will be described.

[0046]The process and device of the present invention have been practically applied in well-known enterprises in the polyester industry. The specific process results are as follows:

[0047] According to the actual production situation, the obtained esterification wastewater was processed through the process flow device provided by the present invention to obtain various product components and their contents, as shown in Table 2.

[0048] Table 2 Esterification wastewater and the content of each component of the product

[0049]

[0050] It can be seen from the results after treatment that after being treated by the wastewater separation tower treatment system of the process flow, the acetaldehyde solution with a purity of more than 95.0% was recovered from the acetaldehyde rectification tower system, and the purity was recovered from the ethylene glycol distillation tower. It i...

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Abstract

The invention discloses a method for recycling ethylene glycol and acetaldehyde from polyester waste water. The method is implemented by the following steps of: (1) introducing esterification waste water into a stripping tower for treating and directly introducing organic matter gas and water vapor collected from a tower top into an acetaldehyde rectifying tower; (2) treating in the acetaldehyde rectifying tower, collecting high-purity acetaldehyde from the tower top and introducing waste water collected from a tower bottom into an ethylene glycol distillation tower; and (3) treating in the ethylene glycol distillation tower, collecting a high-purity ethylene glycol solution from the tower bottom and introducing waste gas and water vapor produced on the tower top into the stripping tower for cyclic treatment. In the method, acetaldehyde and ethylene glycol are continuously collected, so that hydrolysis of byproduct of 2-methyl-1,3-dioxolane in the esterification waste water is continuously performed positively and negatively, acetaldehyde with the concentration of over 95 percent and ethylene glycol with the concentration of over 70 percent are obtained at the end of treatment, and the 2-methyl-1,3-dioxolane is fully hydrolyzed.

Description

technical field [0001] The invention relates to a method for recycling and reusing polyester wastewater in a chemical process, in particular to a method for recycling ethylene glycol and acetaldehyde from polyester wastewater. Background technique [0002] For the production of polyester (PET), especially differentiated polyester, domestic enterprises generally adopt the direct esterification method of terephthalic acid and ethylene glycol, and the concentration of the esterification wastewater discharged is greatly affected by the esterification reaction conditions. The concentration of chemical oxygen demand (COD) in chemical wastewater is about 20000-30000mg / L. The main organic pollutants in polyester wastewater are ethylene glycol and acetaldehyde, among which acetaldehyde, a volatile component, accounts for about 50% of the total organic pollutants. In addition, due to the uneven technology used in the equipment of my country's polyester industry, various The by-product...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C31/20C07C29/10C07C47/06C07C45/42C02F1/20C02F9/10
Inventor 屈一新汪少朋林永明秦鹏
Owner SHANGHAI JUYOU CHEM ENG
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