CN1390826A - Process for depolymerizing waste polyester - Google Patents
Process for depolymerizing waste polyester Download PDFInfo
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- CN1390826A CN1390826A CN 02133517 CN02133517A CN1390826A CN 1390826 A CN1390826 A CN 1390826A CN 02133517 CN02133517 CN 02133517 CN 02133517 A CN02133517 A CN 02133517A CN 1390826 A CN1390826 A CN 1390826A
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Abstract
A process for depolymerizing used polyester (PET) by use of ethanediol and alkali hydrolysis features that the depolymerization at ordinary temp occurs by alkali hydrolysis where ethanediol is used as reaction medium, the EG is obtained by simple distillation, and the TPA-Na is reduced by HCl to obtain phenyldicarboxylic acid (TPA) monomer. Its advantages are simple process, high speed, high depolymerizing rate of PET (99.9%), high recovery rate of TPA (98%) and high recovery rate of EG (96%).
Description
The present invention relates to the useless polyester of a kind of chemical depolymerization, the processing method of producing terephthalic acid (TPA) and ethylene glycol (EG),
Good because of PET resin physical and chemical performance, therefore be widely used in the tape of food, beverage, medicine, sensitive film, finishing material, engineering materials and electronic industry, the industries such as polyster fibre of rag trade.The PET related products promptly becomes refuse usually after disposable use, not only consumed a large amount of petroleum resources but also become one of environment white pollution source.
On recycling, developed countries is gone ahead of the rest.Because recovery system is complete, mainly take on the processing mode to disperse to collect, focus on mode on a large scale, and be that major technique develops and four kinds of existing depolymerization methods with the chemical depolymerization, target is that the useless PET of depolymerization reclaims TPA, EG or PET performed polymer.These four kinds of chemical depolymerization methods may be summarized to be: 1. high-temperature high-pressure hydrolysis reclaims TPA and EG; 2. High Temperature High Pressure methyl alcohol alcoholysis method reclaims DMT and EG; 3. the glycolysis method reclaims synthetic PET performed polymer; 4. the alkaline hydrolysis method reclaims TPA and EG.
Method 1,2 depolymerization speed are fast, but because High Temperature High Pressure and reaction product need rectifying separation, therefore invest huge; Method 3 is single glycolysis, but synthesis under normal pressure, since reaction medium be EG, media environment is single, one of reaction product-EG is identical with medium, makes the thing mode of being separated of EG be reduced to distillation, need not carry out rectifying separation.It is reversible that shortcoming shows as CONTROL PROCESS complexity, long reaction time, reaction, so product thing phase composition complexity, and depolymerization product is the performed polymer of PET, and depolymerization is not thorough, only limits to synthetic PET factory and use; Method 4 is single alkaline hydrolysis method, and advantage is that depolymerization speed is fast, is irreversible reaction, and depolymerization is thorough, but exists side reaction more, and EG needs complicated rectifying separation, the wastewater treatment difficulty, and secondary pollution is serious, invests a series of shortcomings such as bigger.
At the deficiency of above-mentioned technological method, the invention provides the technological method of the useless PET of a kind of pure alkali associating depolymerization.Below in conjunction with the description of drawings technical solution of the present invention:
Accompanying drawing 1 is the material variation diagram of depolymerization PET process.
Accompanying drawing 2 is the process flow sheet of depolymerization PET process.
Technical scheme of the present invention is:
Will through pulverizing, clean, the useless PET fragment of exsiccant, EG, NaHCO
3Put into the depolymerization still, each component additional proportion is: PET fragment: EG: NaHCO
3=1: 5: 1.03～1.08.
2. stir, be warming up to 180 ℃ of insulations 25-40 minute to PET depolymerization simultaneously and finish.Depolymerization product is TPA-Na (solid)+EG+ side reaction thing.The ultimate principle of its chemical reaction foundation can be used equation [1] expression:
(n+1)HOCH2CH2OH+nNaOOC-C6H4-COONa+2nCO2
[1]
3. filter and, TPA-Na (solid) is separated with EG, and the side reaction thing that makes all be dissolved in EG is transferred among the isolating EG with pure EG filter wash depolymerization product.But still contain a small amount of EG in TPA-Na (solid) filter cake.
4. dry TPA-Na (solid) filter cake makes TPA-Na (solid) separate fully with wherein EG.
5. the EG that goes out of distillating filtering removes side reaction product and all are dissolved in the impurity of EG.A gained EG part becomes the EG product, and a part is got back to the depolymerization still or is used as the EG liquid of filter wash.EG behind the filter wash can directly get back to the depolymerization still as the depolymerization medium.
Dried TPA-Na (solid) is soluble in water fully 6., and remove by filter all water-insoluble solid impurity, obtain the TPA-Na aqueous solution.
7. the hydrochloric acid of adding and Na ion equivalent in the TPA-Na aqueous solution obtains TPA (being terephthalic acid solid)+NaCl aqueous solution.The ultimate principle of its chemical reaction foundation can be used equation [2] expression:
[2]
8. refilter to separate the TPA (solid filter cake) and the NaCl aqueous solution.Major part is dissolved in acid to this step or impurity soluble in water is removed.
9. with deionized water filter wash TPA (solid filter cake), remove the NaCl that remains among the TPA (solid filter cake) and other water-soluble ion, obtain purified TPA (solid filter cake).
10. dry TPA (solid filter cake) can obtain the solid-state TPA product of white.
The present invention compared with prior art has following technique effect:
1. combine the advantage of the poly-two kinds of methods of ethylene glycol depolymerization and alkaline hydrolysis, overcome its shortcoming simultaneously.Make the technology of the present invention can use common equipment, in normal pressure, unlimited system, quick depolymerization PET under the relatively lower temp condition.Simplify operation, save energy, reduced facility investment significantly.Employing is with normal NaHCO
3And the depolymerization reaction between PET is an irreversible reaction, until changing the alkaline hydrolysis product fully into.Therefore depolymerization is thorough, rate of recovery height.PET depolymerization rate can reach 99.9%, and the TPA rate of recovery can reach 98%, and the EG rate of recovery can reach 96%.
2. adopt ethylene glycol (EG) to make reaction medium, identical with one of reaction product, the therefore EG that can go out with simple distillating method distillating filtering, thus obtain to satisfy the pure EG product of relevant CNS.Simultaneously according to different with side reaction product impurity and the side reaction products removed of the initial boiling point of EG with the impurity that is dissolved in EG.
3. all the other impurity are because of twice chemical transformation in this technological process experience alkali and acid, its product or water-soluble, or it is water insoluble, therefore all removed by filtration in the technological process or filter wash, final drying can obtain to satisfy the TPA monomer of corresponding CNS through the TPA of deionized water filter wash filter cake.
4. the present invention only adopts the construction equipment that routinizes to implement, invest little, in being suitable for, small-scale compartmentation focuses on useless PET.
Embodiment 1:
Will through pulverizing, clean, the useless PET fragment of exsiccant, EG, NaHCO
3Put into the depolymerization still, each component additional proportion is: PET fragment: EG: NaHCO
3=1: 5: 1.03; Material in the stirring tank is warming up to 180 ℃ of insulations 25 minutes to PET depolymerization simultaneously and finishes, and depolymerization product is TPA-Na (solid)+EG+ side reaction thing; Filter and, TPA-Na (solid) is separated with EG, and the side reaction thing that makes all be dissolved in EG is transferred among the isolating EG with pure EG filter wash depolymerization product; Dry TPA-Na (solid) filter cake makes TPA-Na (solid) separate fully with wherein EG, obtains the solid-state TPA-Na white powder of exsiccant; The EG that distillating filtering goes out removes side reaction product and all are dissolved in the impurity of EG, and a gained EG part becomes the EG product, and a part is got back to the depolymerization still or is used as the EG liquid of filter wash.The used EG of filter wash can directly get back to the depolymerization still as the depolymerization medium; Dried TPA-Na (pressed powder) is soluble in water fully, and remove by filter all water-insoluble solid impurity, obtain the TPA-Na aqueous solution; The hydrochloric acid of adding and Na ion equivalent obtains TPA (being terephthalic acid solid)+NaCl aqueous solution in the TPA-Na aqueous solution; Refilter and obtain the TPA (solid filter cake) and the NaCl aqueous solution; With deionized water filter wash TPA (solid filter cake), obtain purified TPA (solid filter cake); Dry TPA (solid filter cake) can obtain the solid-state TPA product of white.
Embodiment 2:
At depolymerization component ratio be: PET fragment: EG: NaHCO by the preparation of embodiment 1 method
3=1: 5: 1.08, the postorder method of pressing embodiment 1 again obtained EG and TPA product.
Embodiment 3:
When carrying out depolymerization reaction by embodiment 1 method, material in the stirring tank is warming up to 180 ℃ of insulations 40 minutes to PET depolymerization simultaneously and finishes.Press the postorder method of embodiment 1 again, obtain EG and TPA product.
Embodiment 4:
When carrying out depolymerization reaction by embodiment 2 methods, material in the stirring tank is warming up to 180 ℃ of insulations 40 minutes to PET depolymerization simultaneously and finishes.Press the postorder method of embodiment 1 again, obtain EG and TPA product.
Claims (1)
1. the depolymerization method of a useless polyester is characterized in that, this method comprises the following steps:
A. will through pulverizing, clean, the useless PET fragment of exsiccant, EG, NaHCO
3Put into the depolymerization still, each component additional proportion is: PET fragment: EG: NaHCO
3=1: 5: 1.03～1.08;
B. stir, be warming up to 180 ℃ of insulations 25-40 minute to PET depolymerization simultaneously and finish.Depolymerization product is TPA-Na (solid)+EG+ side reaction thing;
C. filter and use pure EG filter wash depolymerization product, TPA-Na (solid) is separated with EG, and the side reaction thing that makes all be dissolved in EG is transferred among the isolating EG;
D. dry TPA-Na (solid) filter cake makes TPA-Na (solid) separate fully with wherein EG;
E. the EG that goes out of distillating filtering removes side reaction product and all are dissolved in the impurity of EG.A gained EG part becomes the EG product, and a part is got back to the depolymerization still or is used as the EG liquid of filter wash;
F. dried TPA-Na (solid) is soluble in water fully, and remove by filter all water-insoluble solid impurity, obtain the TPA-Na aqueous solution;
G. the hydrochloric acid of adding and Na ion equivalent in the TPA-Na aqueous solution obtains TPA (being terephthalic acid solid)+NaCl aqueous solution;
H. refilter to separate the TPA (solid filter cake) and the NaCl aqueous solution.With major part be dissolved in acid or impurity soluble in water remove;
I. use deionized water filter wash TPA (solid filter cake), remove the NaCl that remains among the TPA (solid filter cake) and other water-soluble ion, obtain purified TPA (solid filter cake);
J. dry TPA (solid filter cake) can obtain the solid-state TPA product of white.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02133517 CN1390826A (en) | 2002-07-24 | 2002-07-24 | Process for depolymerizing waste polyester |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02133517 CN1390826A (en) | 2002-07-24 | 2002-07-24 | Process for depolymerizing waste polyester |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101531581A (en) * | 2008-03-13 | 2009-09-16 | 徐晶 | Regenerative method of PET wastes |
| CN102250449A (en) * | 2011-06-27 | 2011-11-23 | 沈阳化工大学 | Process for synthesizing saturated polyester resin by using recycled terephthalic acid |
| CN102532591A (en) * | 2012-02-22 | 2012-07-04 | 中南大学 | Method for depolymerizing waste polyester bottle |
| CN102617337A (en) * | 2012-03-19 | 2012-08-01 | 惠州市长润发涂料有限公司 | Method for recycling waste polyester (PET) |
| EP2719529A1 (en) | 2012-10-10 | 2014-04-16 | Armacell Enterprise GmbH | Prevention of depolymerization of polyalkylene terephthalate in laminated structures |
| CN107254021A (en) * | 2017-06-20 | 2017-10-17 | 江苏锐康新材料科技有限公司 | A kind of regenerating and modifying method of thermosetting unsaturated polyester resin waste |
| CN110255947A (en) * | 2019-05-22 | 2019-09-20 | 湖南昌迪环境科技有限公司 | A kind of grinding aid and its application |
| CN114181037A (en) * | 2021-12-14 | 2022-03-15 | 石泰山 | Method for producing sodium acetate by PET polyester alkali depolymerization |
| CN114195632A (en) * | 2021-12-08 | 2022-03-18 | 南京道港贸易有限公司 | Terephthalic acid, preparation method thereof and method for recycling polyethylene glycol terephthalate with high polymerization degree |
-
2002
- 2002-07-24 CN CN 02133517 patent/CN1390826A/en active Pending
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101531581A (en) * | 2008-03-13 | 2009-09-16 | 徐晶 | Regenerative method of PET wastes |
| CN101531581B (en) * | 2008-03-13 | 2013-06-12 | 香港威思化工有限公司 | Regenerative method of PET wastes |
| CN102250449A (en) * | 2011-06-27 | 2011-11-23 | 沈阳化工大学 | Process for synthesizing saturated polyester resin by using recycled terephthalic acid |
| CN102250449B (en) * | 2011-06-27 | 2012-11-28 | 沈阳化工大学 | Process for synthesizing saturated polyester resin by using recycled terephthalic acid |
| CN102532591B (en) * | 2012-02-22 | 2013-12-04 | 中南大学 | Method for depolymerizing waste polyester bottle |
| CN102532591A (en) * | 2012-02-22 | 2012-07-04 | 中南大学 | Method for depolymerizing waste polyester bottle |
| CN102617337A (en) * | 2012-03-19 | 2012-08-01 | 惠州市长润发涂料有限公司 | Method for recycling waste polyester (PET) |
| EP2719529A1 (en) | 2012-10-10 | 2014-04-16 | Armacell Enterprise GmbH | Prevention of depolymerization of polyalkylene terephthalate in laminated structures |
| CN107254021A (en) * | 2017-06-20 | 2017-10-17 | 江苏锐康新材料科技有限公司 | A kind of regenerating and modifying method of thermosetting unsaturated polyester resin waste |
| CN110255947A (en) * | 2019-05-22 | 2019-09-20 | 湖南昌迪环境科技有限公司 | A kind of grinding aid and its application |
| CN110255947B (en) * | 2019-05-22 | 2022-03-04 | 湖南昌迪环境科技有限公司 | Grinding aid and application thereof |
| CN114195632A (en) * | 2021-12-08 | 2022-03-18 | 南京道港贸易有限公司 | Terephthalic acid, preparation method thereof and method for recycling polyethylene glycol terephthalate with high polymerization degree |
| CN114181037A (en) * | 2021-12-14 | 2022-03-15 | 石泰山 | Method for producing sodium acetate by PET polyester alkali depolymerization |
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