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Polyethylene terephthalate waste recovery process

A technology of waste recycling and process, which is applied in plastic recycling, recycling technology, carboxylate preparation, etc. It can solve the problems of no steps related to decolorization, difficult recovery of ethylene glycol, and difficulty in process realization, etc., and achieve rotary evaporation recovery Excellent process, improved alcoholysis rate, and low process energy consumption

Inactive Publication Date: 2017-10-20
宜兴市创新精细化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of the acidic hydrolysis method are: a large amount of concentrated acid and strong alkali consumed by the reaction are difficult to recycle, easily cause environmental pollution, and the ethylene glycol produced is also difficult to recycle; the alkaline hydrolysis method also has waste alkali to be discharged, Pollution of the environment requires appropriate environmental protection treatment; neutral hydrolysis needs to be carried out under high temperature and high pressure, or alkali is used as a catalyst, and the depolymerization product contains a large amount of impurities, which cannot be directly used, and subsequent treatment is troublesome; methanol depolymerization method The process is relatively simple, but the product purification is complicated, and the quality of the final product is low. Due to the long reaction time of methanol degradation under ordinary conditions, the decomposition is not complete, and the degradation rate of methanol depolymerization PET to DMT that has been realized is not more than 90%, which is not conducive to industrialization. continuous production; the ethylene glycol depolymerization process is relatively complicated
The reaction conditions of the supercritical ethylene glycol depolymerization method are harsh, requiring high temperature and high pressure, and the process is difficult to realize and the cost is high
[0004] The Chinese invention patent with the application publication number CN101906218A discloses a method for recycling polyester waste by atmospheric pressure alcoholysis. Although the purpose of recycling polyester waste can be achieved, there are no steps related to decolorization, so the method does not It is suitable for the recycling of colored polyester waste, so it cannot solve the problem of recycling colored polyester waste

Method used

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  • Polyethylene terephthalate waste recovery process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] A kind of polyester waste recovery process that present embodiment provides, comprises following raw material:

[0036] PET waste (recycled green beverage bottles) - 100kg;

[0037] Ethylene glycol (AR grade)-200kg-Nanjing Chemical Reagent Co., Ltd.;

[0038] Zinc acetate-0.5kg-Nanjing Chemical Reagent Co., Ltd.;

[0039] Calcium chloride-2kg-Nanjing Chemical Reagent Co., Ltd.;

[0040] Acetone-5kg-Nanjing Chemical Reagent Co., Ltd.;

[0041] Activated carbon-10kg-Nanjing Chemical Reagent Co., Ltd.;

[0042] Specific steps are as follows:

[0043] S1, crushing the PET waste, cleaning and drying;

[0044] S2. Dry and clean PET waste, ethylene glycol (EG) and zinc acetate are added to the reaction kettle together, heated to 196°C, stirred and mixed at a constant temperature for about 3 hours, until the depolymerization reaction is complete;

[0045] S3. After the reaction is completed, the temperature is lowered to 135° C., and rapid hot filtration is obtained to ob...

Embodiment 2

[0053] A kind of polyester waste recovery process that present embodiment provides, comprises following raw material:

[0054] PET waste (recycled green beverage bottles) - 150kg;

[0055] EG (AR grade)-300kg-Nanjing Chemical Reagent Co., Ltd.;

[0056] Zinc acetate-0.75kg-Nanjing Chemical Reagent Co., Ltd.;

[0057] Calcium chloride-3kg-Nanjing Chemical Reagent Co., Ltd.;

[0058] Acetone-7.5kg-Nanjing Chemical Reagent Co., Ltd.;

[0059] Activated carbon-15kg-Nanjing Chemical Reagent Co., Ltd.;

[0060] Specific steps are as follows:

[0061] S1, crushing the PET waste, cleaning and drying;

[0062] S2. Dry and clean PET waste, EG and zinc acetate are added to the reaction kettle together, heated to 196°C, stirred and mixed at a constant temperature for about 2.5 hours, until the depolymerization reaction is complete;

[0063] S3. After the reaction is completed, the temperature is lowered to 125° C., and rapid hot filtration is obtained to obtain the primary filtrate ...

Embodiment 3

[0071] A kind of polyester waste recovery process that present embodiment provides, comprises following raw material:

[0072] PET waste (recycled green beverage bottles) - 200kg;

[0073] EG (AR grade)-400kg-Nanjing Chemical Reagent Co., Ltd.;

[0074] Zinc acetate-2kg-Nanjing Chemical Reagent Co., Ltd.;

[0075] Calcium chloride-4kg-Nanjing Chemical Reagent Co., Ltd.;

[0076] Acetone-10kg-Nanjing Chemical Reagent Co., Ltd.;

[0077] Activated carbon-20kg-Nanjing Chemical Reagent Co., Ltd.;

[0078] Specific steps are as follows:

[0079] S1, crushing the PET waste, cleaning and drying;

[0080] S2. Dry and clean PET waste, EG and zinc acetate are added to the reaction kettle together, heated to 196°C, stirred and mixed at a constant temperature for about 3.5 hours, until the depolymerization reaction is complete;

[0081] S3. After the reaction is completed, the temperature is lowered to 145° C., and the filtrate is quickly heated to obtain a primary filtrate and colo...

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Abstract

Relating to the resource regeneration field, the invention discloses a polyethylene terephthalate (PET) waste recovery process, and solves the recovery problem of colored PET waste. The method includes the steps of: S1. crushing, cleaning and drying PET waste; S2. adding the treated PET waste, EG and a catalyst into a reaction kettle, carrying out depolymerization reaction completely at a constant temperature of 170-210DEG C; S3. performing cooling to 125-145DEG C, and conducting hot filtration to obtain primary filtrate and unreacted PET; S4. distilling the primary filtrate to obtain EG; S5. adding a solvent into the distilled liquid, and performing hot filtration to obtain secondary filtrate and an oligomer of BHET; S6. adding a decolorizing agent into the secondary filtrate, and conducting hot filtration to obtain tertiary filtrate; S7. subjecting the tertiary filtrate to cooling crystallization to precipitate needle crystals, conducting filtration to obtain monomer BHET, and performing drying at 60DEG C; S8. conducting polycondensation under a low vacuum condition, and carrying out final polycondensation under a high vacuum condition; and S9. carrying out strip casting, cooling, grain cutting and drying, thus finally obtaining the PET particle product.

Description

technical field [0001] The invention relates to the technical field of resource regeneration, in particular to a polyester waste recycling process. Background technique [0002] Polyethylene terephthalate (PET, polyester for short) is an important industrial raw material, and its main products include beverage bottles, fibers, films, film bases, electrical insulation materials and engineering plastics, etc., polyethylene terephthalate Ethylene glycol ester is obtained by homopolymerization of ethylene terephthalate, or by polymerization of terephthalic acid and ethylene glycol. With the sharp increase in the annual output of polyester products, the polyester wastes brought by polyester products are also increasing rapidly. In addition, in the process of forming polyester products, various scrap products and leftovers are often produced. Due to the strong chemical inertness of polyethylene terephthalate, it is difficult to degrade or be decomposed by microorganisms in natura...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G63/183C08G63/78C08J11/24C08J11/06C07C67/317C07C67/48C07C67/00C07C69/82
CPCC07C67/00C07C67/317C07C67/48C08G63/183C08G63/78C08J11/06C08J11/24C07C69/82Y02W30/62
Inventor 罗竑
Owner 宜兴市创新精细化工有限公司
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