CN112174781A - Method and equipment for decoloring ethylene glycol - Google Patents
Method and equipment for decoloring ethylene glycol Download PDFInfo
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- CN112174781A CN112174781A CN202011224149.XA CN202011224149A CN112174781A CN 112174781 A CN112174781 A CN 112174781A CN 202011224149 A CN202011224149 A CN 202011224149A CN 112174781 A CN112174781 A CN 112174781A
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- ethylene glycol
- decoloring
- cyclic regeneration
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- adsorption resin
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
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- Treatment Of Liquids With Adsorbents In General (AREA)
Abstract
The invention provides a method for decoloring ethylene glycol, which comprises the following steps: the ethylene glycol recovered in the process of producing DMT by continuously alcoholyzing waste polyester is decolorized by circularly regenerating the adsorbent resin. The inventors also provide an ethylene glycol decoloring apparatus, comprising: the device comprises a recycled ethylene glycol storage tank, a first cyclic regeneration adsorption resin, a second cyclic regeneration adsorption resin and a decolored ethylene glycol storage tank; the recycling ethylene glycol storage tank is connected with a feed inlet of the first cyclic regeneration adsorption resin, a discharge outlet of the first cyclic regeneration adsorption resin is connected with a feed inlet of the second cyclic regeneration adsorption resin, and a discharge outlet of the second cyclic regeneration adsorption resin is connected with the decoloring ethylene glycol storage tank. The method and the equipment can be continuously operated, can ensure that the light transmittance of the decolorized glycol reaches more than 95 percent, and can be continuously recycled in the alcoholysis process.
Description
Technical Field
The invention relates to the field of waste polyester recovery, in particular to a method for decoloring ethylene glycol recovered in the process of producing DMT (dimethyl terephthalate) by continuously alcoholyzing waste polyester through a cyclic regeneration adsorbent resin.
Background
The Chinese name of PET is: polyethylene terephthalate belongs to polyester. PET is largely used as fiber, and engineering plastic resins can be classified into non-engineering plastic grades and engineering plastic grades, and the non-engineering plastic grades are mainly used for bottles, films, sheets, baking-resistant food containers and the like. PET chips are further classified into fiber-grade polyester chips and non-fiber-grade polyester chips. The fiber grade polyester is used for manufacturing polyester staple fibers and polyester filaments, is a raw material for processing fibers and related products for polyester fiber enterprises, and is a variety with the largest yield in chemical fibers.
The existing recovery method of waste polyester mainly comprises physical recovery and chemical recovery. The physical recovery method is simpler and more economical, but the performance of the regenerated product is poor. One important direction of chemical recovery is to alcoholyze the waste polyester with Ethylene Glycol (EG) to produce dihydroxy terephthalate (BHET) or oligomers, then perform transesterification in methanol to produce dimethyl terephthalate (DMT) and ethylene glycol, obtain pure DMT by purification, and use the pure DMT as raw material for polyester production, and use the purified methanol and ethylene glycol in the reaction system to realize the recycling of the waste polyester. However, the recovered ethylene glycol has a high color and is not suitable for direct use.
The Chinese patent application No. 201611176517.1 discloses an electrochemical decoloring method, which comprises electrolyzing waste liquid in an electrolytic bath to perform electrochemical decoloring; the electrolyzed product is then rotary evaporated for recovery of the polyol. 201811384512.7 discloses a method for decolorizing a polyester alcoholysis product BHET by using ion-modified activated carbon, which is used for improving the adsorption performance of the BHET on dyes contained in the BHET, and decolorizing in the intermediate link of reaction, so that the quality of the recovered ethylene glycol is higher.
Disclosure of Invention
In order to achieve the purpose, the inventor provides a novel ethylene glycol decoloring method and equipment, which can be continuously operated, effectively reduce the chroma of the recovered ethylene glycol and enable the light transmittance of the ethylene glycol to reach more than 95%.
The invention provides a method for decoloring ethylene glycol, which comprises the following steps: the ethylene glycol recovered in the process of producing DMT by continuously alcoholyzing waste polyester is decolorized by circularly regenerating the adsorbent resin.
Further, the ethylene glycol is decolorized by two-stage cyclic regeneration adsorption resin in series.
Further, the decolorization is carried out at 15 to 30 ℃.
Further, the light transmittance of the decolorized ethylene glycol is more than 95%.
The inventors also provide an ethylene glycol decoloring apparatus, comprising: the device comprises a recycled ethylene glycol storage tank, a first cyclic regeneration adsorption resin, a second cyclic regeneration adsorption resin and a decolored ethylene glycol storage tank; the recycling ethylene glycol storage tank is connected with a feed inlet of the first cyclic regeneration adsorption resin, a discharge outlet of the first cyclic regeneration adsorption resin is connected with a feed inlet of the second cyclic regeneration adsorption resin, and a discharge outlet of the second cyclic regeneration adsorption resin is connected with the decoloring ethylene glycol storage tank.
Further, the ethylene glycol decoloration equipment also comprises a third cyclic regeneration adsorption resin and a fourth cyclic regeneration adsorption resin, the recovered ethylene glycol storage tank is connected with the feed inlet of the third cyclic regeneration adsorption resin, the discharge outlet of the third cyclic regeneration adsorption resin is connected with the feed inlet of the fourth cyclic regeneration adsorption resin, and the discharge outlet of the fourth cyclic regeneration adsorption resin is connected with the decoloration ethylene glycol storage tank.
Different from the prior art, the technical scheme at least comprises the following beneficial effects: the method can be continuously operated, can ensure that the light transmittance of the decolorized ethylene glycol reaches over 95 percent, and can be continuously recycled in the alcoholysis process.
Drawings
FIG. 1 shows a rectifying and dehydrating apparatus as described in example 1.
Description of reference numerals:
1. storage tank for recovering ethylene glycol
2. First cycle regeneration of the adsorbent resin
3. Second cycle regeneration of the adsorbent resin
4. Third cycle regeneration of the adsorption resin
5. Fourth cycle regeneration of the adsorbent resin
6. And (5) a decoloration ethylene glycol storage tank.
Detailed Description
To explain technical contents, structural features, and objects and effects of the technical solutions in detail, the following detailed description is given with reference to the accompanying drawings in conjunction with the embodiments.
The present embodiment adopts: the Chinese patent application with application number 201910617806.8 discloses a continuous alcoholysis recovery method of waste polyester, which comprises the steps of carrying out continuous alcoholysis and ester exchange on a waste polyester raw material, an alcoholysis agent and an alcoholysis catalyst in a molten state to synthesize an ester exchange product; and performing DMT crystallization and methanol washing on the ester exchange product, and recovering the solvent in the processes of DMT crystallization and methanol washing to obtain ethylene glycol recovery liquid.
Example 1 an ethylene glycol decolorization apparatus
Referring to fig. 1, an apparatus for decoloring ethylene glycol, the apparatus comprising: a recovered glycol storage tank 1, a first circularly regenerated adsorbent resin 2, a second circularly regenerated adsorbent resin 3, a third circularly regenerated adsorbent resin 4, a fourth circularly regenerated adsorbent resin 5 and a decolorized glycol storage tank 6; the ethylene glycol recovery storage tank 1 is connected with a feed inlet of a first cyclic regeneration adsorption resin 2, a discharge outlet of the first cyclic regeneration adsorption resin 2 is connected with a feed inlet of a second cyclic regeneration adsorption resin 3, and a discharge outlet of the second cyclic regeneration adsorption resin 3 is connected with a decoloration ethylene glycol storage tank 6; the recycling ethylene glycol storage tank 1 is connected with a feed inlet of a third cyclic regeneration adsorption resin 4, a discharge outlet of the third cyclic regeneration adsorption resin 4 is connected with a feed inlet of a fourth cyclic regeneration adsorption resin 5, and a discharge outlet of the fourth cyclic regeneration adsorption resin 5 is connected with a decoloration ethylene glycol storage tank 6.
When the ethylene glycol is decolorized at the normal temperature of 15-30 ℃, in order to ensure the continuity of production, a first regeneration system is formed by the first recycled resin and the second recycled resin; and the second regeneration system formed by the third regenerated resin circulation and the fourth regenerated resin circulation is used in turn. The light transmittance of the resin and the ethylene glycol were simultaneously measured using an on-line spectrophotometer. The light transmittance of the ethylene glycol before decolorization is 79%, and the light transmittance after decolorization reaches 95%.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrases "comprising … …" or "comprising … …" does not exclude the presence of additional elements in a process, method, article, or terminal that comprises the element. Further, herein, "greater than," "less than," "more than," and the like are understood to exclude the present numbers; the terms "above", "below", "within" and the like are to be understood as including the number.
It should be noted that, although the above embodiments have been described herein, the invention is not limited thereto. Therefore, based on the innovative concepts of the present invention, the technical solutions of the present invention can be directly or indirectly applied to other related technical fields by making changes and modifications to the embodiments described herein, or by using equivalent structures or equivalent processes performed in the content of the present specification and the attached drawings, which are included in the scope of the present invention.
Claims (6)
1. The method for decoloring the ethylene glycol is characterized by comprising the following steps of:
the ethylene glycol recovered in the process of producing DMT by continuously alcoholyzing waste polyester is decolorized by circularly regenerating the adsorbent resin.
2. The ethylene glycol decolorization method according to claim 1, wherein the ethylene glycol is decolorized by two-stage cyclic regeneration of adsorption resins in series.
3. The method for decoloring ethylene glycol according to claim 1, wherein the decoloring is performed at 15 to 30 ℃.
4. The method for decoloring ethylene glycol according to claim 1, wherein the transmittance of the decolored ethylene glycol is 95% or more.
5. An ethylene glycol decolorization apparatus, characterized in that the ethylene glycol decolorization apparatus includes: the device comprises a recycled ethylene glycol storage tank, a first cyclic regeneration adsorption resin, a second cyclic regeneration adsorption resin and a decolored ethylene glycol storage tank; the recycling ethylene glycol storage tank is connected with a feed inlet of the first cyclic regeneration adsorption resin, a discharge outlet of the first cyclic regeneration adsorption resin is connected with a feed inlet of the second cyclic regeneration adsorption resin, and a discharge outlet of the second cyclic regeneration adsorption resin is connected with the decoloring ethylene glycol storage tank.
6. The ethylene glycol decoloring apparatus according to claim 5, wherein the ethylene glycol decoloring apparatus further comprises a third recycling adsorbent resin and a fourth recycling adsorbent resin, the recycled ethylene glycol storage tank is connected to a feed inlet of the third recycling adsorbent resin, a discharge outlet of the third recycling adsorbent resin is connected to a feed inlet of the fourth recycling adsorbent resin, and a discharge outlet of the fourth recycling adsorbent resin is connected to the decoloring ethylene glycol storage tank.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011224149.XA CN112174781A (en) | 2020-11-05 | 2020-11-05 | Method and equipment for decoloring ethylene glycol |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011224149.XA CN112174781A (en) | 2020-11-05 | 2020-11-05 | Method and equipment for decoloring ethylene glycol |
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| Publication Number | Publication Date |
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| CN112174781A true CN112174781A (en) | 2021-01-05 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011224149.XA Withdrawn CN112174781A (en) | 2020-11-05 | 2020-11-05 | Method and equipment for decoloring ethylene glycol |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6706843B1 (en) * | 1999-10-22 | 2004-03-16 | Teijin Limited | Method for separating and recovering dimethyl terephthalate and ethylene glycol from polyester waste |
| CN109574835A (en) * | 2018-11-20 | 2019-04-05 | 江南大学 | A kind of method of ion modification activity carbon decoloring polyesterols solution product BHET |
-
2020
- 2020-11-05 CN CN202011224149.XA patent/CN112174781A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6706843B1 (en) * | 1999-10-22 | 2004-03-16 | Teijin Limited | Method for separating and recovering dimethyl terephthalate and ethylene glycol from polyester waste |
| CN109574835A (en) * | 2018-11-20 | 2019-04-05 | 江南大学 | A kind of method of ion modification activity carbon decoloring polyesterols solution product BHET |
Non-Patent Citations (1)
| Title |
|---|
| 无: ""脱色树脂工艺的介绍"", 《无》 * |
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Application publication date: 20210105 |
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