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Method for online recycling of pet polymer waste

A waste material and polymerization reaction technology, applied in recycling technology, plastic recycling, etc., can solve the problems of restricting the subsequent application of recycled polyester products, high degree of thermal degradation and thermal oxygen degradation, complex process steps and devices, etc., and achieve optimal solutions The effect of polyreaction process, improving thermal oxygen performance and reducing evaporation

Active Publication Date: 2019-09-20
SINOPEC YIZHENG CHEM FIBER +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The obtained BHET must be purified by crystallization method, which requires complex process steps and equipment
[0006] Chinese patent 200910081359.5 discloses a method using methanol and co-solvent to depolymerize waste polyester under supercritical conditions to obtain dimethyl terephthalate (DMT) and ethylene glycol. Depolymerization under supercritical conditions requires high energy consumption and requires Increase equipment recovery of co-solvents
Polyester waste is melted and extruded, and the degree of thermal degradation and thermal oxygen degradation is high, which limits the subsequent application of recycled polyester products
[0013] The above literature reports are all at the level of theoretical and experimental research, without mentioning how to recycle the polymerized waste generated in the PET production process online

Method used

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  • Method for online recycling of pet polymer waste
  • Method for online recycling of pet polymer waste
  • Method for online recycling of pet polymer waste

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0056] Using a 20L reactor, add 6.0kg of waste PET particles, 1.0kg of EG, and 5.0g of deionized water into the 20L reactor, replace the air in the reactor with nitrogen, and feed the vapor phase mixture in the high-temperature esterification reactor to maintain the gauge pressure in the reactor. At 0.1MPa. Turn on the kettle to heat, and let it stand for 30 minutes. After the temperature of the liquid in the kettle rises above 200°C, start stirring at a low speed. After stirring at low speed for 10 min, adjust the stirring speed to normal speed. Under the conditions of a pressure of 0.10-0.40 MPa and a temperature of 220°C-260°C, the mixture is stirred for 2.0 hours to carry out a high-temperature and high-pressure depolymerization reaction. The material is released after pressure relief to obtain a PET depolymerized product with an intrinsic viscosity of 0.070dL / g, without abnormal color.

[0057] Using a 20L polymerization reactor, 4.5kg PTA, 2.7kg EG, 1.8g Sb 2 EG 3 , ...

Embodiment 2

[0059] Using a 20L reactor, 6.0kg of waste PET particles, 1.0kg of EG, 5.0g of deionized water, ZnAC 2 0.6g was added to the 20L reaction kettle together, the air in the kettle was replaced with nitrogen, and the vapor phase mixture was passed into the high-temperature esterification kettle to keep the gauge pressure in the kettle at 0.1MPa. Turn on the kettle to heat, and let it stand for 30 minutes. After the temperature of the liquid in the kettle rises above 200°C, start stirring at a low speed. After stirring at low speed for 10 min, adjust the stirring speed to normal speed. Under the conditions of a pressure of 0.10-0.30 MPa and a temperature of 220°C-250°C, the mixture is stirred for 1.5 hours to carry out a high-temperature and high-pressure depolymerization reaction. The depolymerized PET product with an intrinsic viscosity of 0.065dL / g was obtained after pressure release and discharging, and the color was good.

[0060] Using a 20L polymerization reactor, 4.5kg PT...

Embodiment 3

[0062] Using 20L reactor, waste PET particles 6.0kg, EG 0.5kg, deionized water 2.5g, ZnAC 2 0.6g and 10101.2g of antioxidant were added to the 20L reaction kettle together, the air in the kettle was replaced with nitrogen, and the vapor phase mixture was introduced into the high-temperature esterification kettle to keep the gauge pressure in the kettle at 0.1MPa. Turn on the kettle to heat, and let it stand for 30 minutes. After the temperature of the liquid in the kettle rises above 200°C, start stirring at a low speed. After stirring at low speed for 10 min, adjust the stirring speed to normal speed. Under the conditions of a pressure of 0.10-0.30 MPa and a temperature of 220°C-250°C, stirring for 1.0 hr, the high-temperature and high-pressure depolymerization reaction is carried out. The depolymerized PET product with an intrinsic viscosity of 0.075dL / g was obtained by releasing the pressure and discharging, with excellent color and luster.

[0063] Using a 20L polymeriza...

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Abstract

The invention relates to a method for online recycling PET polymerization waste. The method comprises the following main steps: (1) polymerization waste generated in a production process of PET is crushed, and the polymerization waste and tower bottoms of an esterification technology tower are added to a depolymerization kettle; (2) a vapor mixture in an esterification reaction kettle is supplied to the depolymerization kettle until the pressure in the kettle is balanced with the pressure of a polymerization esterification system; (3) a depolymerization reaction is performed under high temperature and high pressure conditions to obtain a low-molecular-weight PET depolymerization substance with the intrinsic viscosity of 0.05-0.15dL / g; (4) the depolymerization substance is loaded to an esterification system and subjected to pre-condensation, final polycondensation, pelleting and the like to prepare a polyester chip. The method realizes whole online recycling of the PET polymerization waste; the performance of obtained recycled polyester is equivalent to the performance of conventional polyester; the production cost of PET is significantly lowered.

Description

technical field [0001] The invention belongs to the field of polymer compound production, and in particular relates to a method for on-line recycling of polymerized waste produced in the PET production process. Background technique [0002] Polyethylene terephthalate (PET) has the characteristics of light weight, high strength, good transparency, good heat resistance, good dimensional stability and excellent chemical resistance, and is widely used in beverage bottles, fibers, In the fields of film, sheet level and electrical insulation materials, it has become the largest variety of products in synthetic fibers. However, the large-scale production and use of PET is bound to be accompanied by the discharge and generation of a large amount of waste. At the end of 2013, China's polyester PET production capacity was as high as 43 million tons. The operating rate of the polyester industry was calculated at 60%, and the waste rate of the polymerization process was calculated at 0...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08J11/24C08G63/183
CPCY02W30/62
Inventor 王余伟王金堂朱兴松张金峰
Owner SINOPEC YIZHENG CHEM FIBER