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Method and equipment for obtaining DMT from rectification kettle residues

A rectifying still and condenser technology, applied in the field of PET recycling, can solve problems such as low recovery rate and achieve high efficiency

Inactive Publication Date: 2021-02-12
AVANTGARDE SHANGHAI ENVIRONMENTAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In this method, after the alcoholysis tank and the transesterification tank, only one common distillation unit is installed to ensure the recovery of EG and methanol, and the recovery rate is low

Method used

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  • Method and equipment for obtaining DMT from rectification kettle residues

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Embodiment 1

[0041] Embodiment 1 obtains the equipment of DMT in a kind of still residue

[0042] Such as figure 1As shown, the equipment includes a rectification still residual storage tank 1, a thin film evaporator 2, a first condenser 3, and a second condenser 4; the liquid outlet end of the rectification still residual storage tank 1 and the thin film The liquid inlet end of the evaporator 2 is connected, the air outlet of the thin film evaporator 2 is connected with the air inlet of the first condenser 3, and the liquid outlet of the first condenser 3 is connected with the DMT condensate storage tank 5, The air outlet of the first condenser 3 is connected with the air inlet of the second condenser 4, and the liquid outlet of the second condenser 4 is connected with the DMT condensate storage tank 5, and the outlet of the second condenser 4 is The air outlet is connected to the exhaust port of the vacuum pump 6 . After DMT rectification, the still residue enters the thin-film evapora...

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Abstract

The invention provides a method and equipment for obtaining DMT from rectification kettle residues, and the method comprises the following steps: negative pressure evaporation: carrying out the negative pressure evaporation of the rectification kettle residues through a film evaporator, and separating DMT from a gas phase through condensation; wherein the recovery liquid is a transesterification product synthesized by carrying out continuous alcoholysis and transesterification on the waste polyester raw material, an alcoholysis agent and an alcoholysis catalyst in a molten state; carrying outDMT crystallization on the transesterification product, and washing the DMT crystallization with methanol to obtain a DMT filter cake; and purifying the DMT filter cake through a short-process rectification system at the vacuum of 6.65 Kpa and the temperature of 200 DEG C to obtain pure DMT and rectification kettle residues. According to the method disclosed by the invention, the dihydroxy terephthalate, the dihydroxy terephthalate oligomer and the DMT in the kettle residues are separated by adopting a film evaporation mode under negative pressure, so that more than 80% of the DMT in the kettle residues is effectively recycled. The equipment can carry out continuous operation, DMT in kettle residues is continuously extracted, the purity of the obtained DMT is 99.5%, and the efficiency is high.

Description

technical field [0001] The invention relates to the field of PET recycling, in particular to a method and equipment for obtaining DMT from rectification still residue obtained from a continuous alcoholysis recovery method of waste polyester. Background technique [0002] The Chinese name of PET is: polyethylene terephthalate, which belongs to polyester polyester. PET is widely used as fiber, and engineering plastic resin can be divided into two categories: non-engineering plastic grade and engineering plastic grade. Non-engineering plastic grade is mainly used for bottles, films, sheets, and baking-resistant food containers. PET chips are divided into fiber-grade polyester chips and non-fiber-grade polyester chips. Fiber-grade polyester is used to manufacture polyester staple fibers and polyester filaments, and is the raw material for polyester fiber enterprises to process fibers and related products. Polyester is the most produced variety in chemical fibers. [0003] At p...

Claims

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Application Information

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IPC IPC(8): B01D1/22B01D1/30B01D3/10B01D3/14
CPCB01D1/22B01D1/30B01D3/10B01D3/14
Inventor 王读彬方华玉李天源朱恩斌敖四斌陈建华卢旭坤余国清杨伟钱桂梅杨兴宏赫瑞强
Owner AVANTGARDE SHANGHAI ENVIRONMENTAL TECH CO LTD