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Regenerative method of PET wastes

A technology for waste materials and wastes, which is applied in the field of polymer waste recycling, can solve the problems of complex process flow, large alkali-containing wastewater, environmental pollution, etc., and achieves the effect of simple process, environmental protection, and production or purchase cost savings.

Inactive Publication Date: 2009-09-16
HONGKONG VISCOCHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are following deficiencies in its production process: 1. A large amount of waste water containing acid and alkali is produced, which seriously pollutes the environment; 2. The process is complicated and the energy consumption is high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Put 100Kg of waste PET material into the reaction kettle after pulverizing, washing and drying, add 450Kg of ethylene glycol, and then add 100Kg of sodium carbonate after raising the temperature to 180°C, continue to raise the temperature to reflux, keep the steady reflux for 1.5 hours, and then pour it into the reaction kettle Cooling water was passed through to lower the temperature of the system to 120°C, and pressure filtration was carried out at this temperature until the filtration was completed.

[0024] The filter cake is put into a vacuum drier to dry, and the dried filter cake is pulverized and put into an acid analysis kettle, and dissolved with 500Kg boiling water. Then add 30Kg of technical grade sulfuric acid (98%) to precipitate terephthalic acid, centrifuge and dry to obtain refined terephthalic acid (80Kg). Sodium sulfate (80Kg) was recovered by evaporation of the mother liquor obtained by centrifugation.

[0025] The mother liquor after pressure filtr...

Embodiment 2

[0027] Crush, wash and dry 100Kg of waste PET material and put it into the reaction kettle, add 1000Kg of ethylene glycol, heat up to 160°C, then add 150Kg of calcium carbonate, continue to heat up to reflux, keep steady reflux for 2.5 hours, and then cool to 100°C , for pressure filtration.

[0028] The filter cake is put into a vacuum drier for drying. After the dried filter cake is pulverized, it is put into an acid analysis kettle and dissolved with 900Kg boiling water. Then add 60Kg of technical grade sulfuric acid (98%) to separate out terephthalic acid, centrifuge and dry to obtain refined terephthalic acid (78Kg). The mother liquor obtained by centrifugation is evaporated to reclaim calcium sulfate (81Kg).

[0029] The mother liquor after pressure filtration is sent to the distillation still to recover ethylene glycol to obtain ethylene glycol product (28Kg). By-product CO 2 Evacuate through the vent tube.

Embodiment 3

[0031] Put 100Kg of waste PET material into the reaction kettle after pulverizing, washing and drying, add 600Kg of ethylene glycol, heat up to 200°C, then add 100Kg of sodium phosphate, continue to heat up to reflux, keep steady reflux for 2.5 hours, and then cool to 80°C , for pressure filtration.

[0032] The filter cake is put into a vacuum dryer for drying, and the dried filter cake is pulverized and put into an acid analysis kettle, and dissolved with 700Kg boiling water. Then add 120Kg technical grade sulfuric acid (98%) to separate out terephthalic acid, centrifuge and dry to obtain refined terephthalic acid (80Kg). Sodium sulfate (80Kg) was recovered by evaporation of the mother liquor obtained by centrifugation.

[0033] The phosphoric acid ester of ethylene glycol is hydrolyzed to obtain ethylene glycol containing phosphoric acid, and the pure product of ethylene glycol is obtained through distillation to obtain ethylene glycol product (30Kg).

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PUM

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Abstract

The invention discloses a regenerative method of PET wastes, belonging to the field of a recycling method of polymer wastes. The method utilizes ester exchange reaction to reduce polyethylene terephthalate into alkali metal salts or alkaline-earth metal salts of phthalic acid and weak acid radical salts of ethylene glycol and then utilizes acid to reduce alkali metal salts or alkaline-earth metalsalts of phthalic acid into terephthalic acid; and esterolysis and distillation are carried out to weak acid of ethylene glycol so as to obtain the ethylene glycol. Compared with the prior art, the regenerative method of the PET wastes has the characteristics of being economic and environment-friendly and being easy to realize and has good promotion and application values.

Description

technical field [0001] The invention relates to a method for recycling polymer waste, in particular to a regeneration method for PET (polyethylene terephthalate) waste. Background technique [0002] PET waste mainly includes discarded polyester film, polyester bottle flakes, etc. At present, its recycling is mainly used to manufacture PET-related products directly after crushing and granulation. Since PET waste is not suitable for direct use in the manufacture of food packaging, medical and sanitary appliances and other products, more and more PET waste is abandoned because it cannot be used, which seriously threatens the natural environment. On the other hand, in order to produce hygienic and safe PET products, manufacturers also need to purchase terephthalic acid and ethylene glycol at high cost. [0003] Although there are methods for producing terephthalic acid from PET waste in the prior art, most of them are carried out by hydrolysis of esters. The production proces...

Claims

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Application Information

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IPC IPC(8): C07C51/09C07C63/26
Inventor 徐晶
Owner HONGKONG VISCOCHEM CO LTD
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