WO2023231628A1 - 一种实现由废旧聚酯连续化制备高纯bhet单体的工艺及系统 - Google Patents
一种实现由废旧聚酯连续化制备高纯bhet单体的工艺及系统 Download PDFInfo
- Publication number
- WO2023231628A1 WO2023231628A1 PCT/CN2023/089358 CN2023089358W WO2023231628A1 WO 2023231628 A1 WO2023231628 A1 WO 2023231628A1 CN 2023089358 W CN2023089358 W CN 2023089358W WO 2023231628 A1 WO2023231628 A1 WO 2023231628A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- alcoholysis
- thin film
- pipeline
- kettle
- series
- Prior art date
Links
- 229920000728 polyester Polymers 0.000 title claims abstract description 76
- 239000002699 waste material Substances 0.000 title claims abstract description 64
- 239000000178 monomer Substances 0.000 title claims abstract description 44
- 238000000034 method Methods 0.000 title claims abstract description 25
- 238000002360 preparation method Methods 0.000 title abstract description 5
- 238000006136 alcoholysis reaction Methods 0.000 claims abstract description 136
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims abstract description 81
- 239000010409 thin film Substances 0.000 claims abstract description 70
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 62
- QPKOBORKPHRBPS-UHFFFAOYSA-N bis(2-hydroxyethyl) terephthalate Chemical compound OCCOC(=O)C1=CC=C(C(=O)OCCO)C=C1 QPKOBORKPHRBPS-UHFFFAOYSA-N 0.000 claims abstract description 61
- 238000001704 evaporation Methods 0.000 claims abstract description 33
- 230000008020 evaporation Effects 0.000 claims abstract description 33
- 238000001179 sorption measurement Methods 0.000 claims abstract description 26
- 238000011282 treatment Methods 0.000 claims abstract description 15
- 238000002844 melting Methods 0.000 claims abstract description 5
- 230000008018 melting Effects 0.000 claims abstract description 5
- 238000000199 molecular distillation Methods 0.000 claims abstract description 5
- 238000001125 extrusion Methods 0.000 claims abstract description 4
- 238000012546 transfer Methods 0.000 claims description 36
- 239000003054 catalyst Substances 0.000 claims description 11
- 238000004042 decolorization Methods 0.000 claims description 10
- 238000009413 insulation Methods 0.000 claims description 9
- 239000007788 liquid Substances 0.000 claims description 9
- 238000001914 filtration Methods 0.000 claims description 5
- 239000000155 melt Substances 0.000 claims description 5
- 239000007787 solid Substances 0.000 claims description 5
- 238000004128 high performance liquid chromatography Methods 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 4
- 125000004122 cyclic group Chemical group 0.000 claims description 3
- 238000004821 distillation Methods 0.000 claims description 3
- 238000004064 recycling Methods 0.000 abstract description 10
- 238000005265 energy consumption Methods 0.000 abstract description 5
- 239000002904 solvent Substances 0.000 abstract description 5
- 239000000047 product Substances 0.000 description 39
- 229920000139 polyethylene terephthalate Polymers 0.000 description 19
- 239000005020 polyethylene terephthalate Substances 0.000 description 19
- 239000000243 solution Substances 0.000 description 18
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 8
- 238000006068 polycondensation reaction Methods 0.000 description 8
- 238000010924 continuous production Methods 0.000 description 7
- 238000007086 side reaction Methods 0.000 description 6
- 238000002425 crystallisation Methods 0.000 description 5
- 230000008025 crystallization Effects 0.000 description 5
- 238000000746 purification Methods 0.000 description 5
- 230000032050 esterification Effects 0.000 description 4
- 238000005886 esterification reaction Methods 0.000 description 4
- -1 polyethylene terephthalate Polymers 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical group CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 3
- 238000009835 boiling Methods 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 230000008929 regeneration Effects 0.000 description 3
- 238000011069 regeneration method Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 238000005406 washing Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- ZOIORXHNWRGPMV-UHFFFAOYSA-N acetic acid;zinc Chemical compound [Zn].CC(O)=O.CC(O)=O ZOIORXHNWRGPMV-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000006260 foam Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 230000001629 suppression Effects 0.000 description 2
- 239000004246 zinc acetate Substances 0.000 description 2
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 1
- BCBHDSLDGBIFIX-UHFFFAOYSA-N 4-[(2-hydroxyethoxy)carbonyl]benzoic acid Chemical compound OCCOC(=O)C1=CC=C(C(O)=O)C=C1 BCBHDSLDGBIFIX-UHFFFAOYSA-N 0.000 description 1
- LLLVZDVNHNWSDS-UHFFFAOYSA-N 4-methylidene-3,5-dioxabicyclo[5.2.2]undeca-1(9),7,10-triene-2,6-dione Chemical compound C1(C2=CC=C(C(=O)OC(=C)O1)C=C2)=O LLLVZDVNHNWSDS-UHFFFAOYSA-N 0.000 description 1
- PBCJIPOGFJYBJE-UHFFFAOYSA-N acetonitrile;hydrate Chemical group O.CC#N PBCJIPOGFJYBJE-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 238000001944 continuous distillation Methods 0.000 description 1
- 238000002242 deionisation method Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 230000008521 reorganization Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- 238000005809 transesterification reaction Methods 0.000 description 1
- 238000005292 vacuum distillation Methods 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/03—Preparation of carboxylic acid esters by reacting an ester group with a hydroxy group
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/52—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/52—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
- C07C67/54—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation by distillation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/56—Separation; Purification; Stabilisation; Use of additives by solid-liquid treatment; by chemisorption
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
- C07C69/76—Esters of carboxylic acids having a carboxyl group bound to a carbon atom of a six-membered aromatic ring
- C07C69/80—Phthalic acid esters
- C07C69/82—Terephthalic acid esters
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J11/00—Recovery or working-up of waste materials
- C08J11/04—Recovery or working-up of waste materials of polymers
- C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
- C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
Definitions
- the invention relates to a process and system for continuously preparing high-purity BHET monomer from waste polyester, and belongs to the technical field of waste polyester recycling.
- Polyester i.e. polyethylene terephthalate
- polyester has been widely used in food packaging, film sheets, electronic devices, mechanical equipment and other fields because of its good physical and chemical properties. According to statistics, in 2008, my country has become the world's largest producer and consumer of polyester, accounting for more than half of the world's output. In 2015, my country's polyester output reached 35.3 million tons, and in 2019, my country's polyester output reached 50.06 million tons. tons, an increase of 41.8%. Most polyester products become waste products after one use. Therefore, with the rapid development of the polyester industry, the output of waste polyester is also increasing day by day. However, polyester has strong chemical inertness and is difficult to degrade or be decomposed by microorganisms when stored naturally.
- BHET ethylene terephthalate, its CAS number is 959-26-2
- PET polyethylene terephthalate
- high-purity BHET monomer can be produced from waste polyester, regenerated polyester can be produced through further polycondensation reaction, thereby truly realizing the recycling and regeneration of waste PET polyester.
- DEG or DEG ester are very similar to those of EG or BHET. Similar to BHET, it is extremely difficult to phase separate from BHET, so that high-purity BHET monomer cannot be produced.
- Chinese invention patent application with application number 201810921762.3 discloses the use of recrystallization and activated carbon decolorization to purify crude BHET, that is: first add 90°C hot water to the crude BHET that has been distilled under reduced pressure, and heat The amount of water used is 200% of the mass of the alcoholysis solution after vacuum distillation, followed by stirring, filtration and repeated water washing 3 to 5 times, and then decolorization and filtration with activated carbon.
- the decolorized filtrate is cooled to 40°C to crystallize BHET and obtain refined BHET; however, this purification treatment method will not only produce more wastewater and waste ethylene glycol, resulting in high pressure for waste liquid treatment, but also has difficulties in thermal filtration (easy to block Plug filter), long activated carbon decolorization and cooling precipitation time, and difficulty in drying. Not only do the color and purity of the obtained BHET fail to meet the needs for the preparation of high-quality PET products, but also continuous production cannot be achieved. ; Although the Chinese invention patent with patent number 200510097626.
- Obtaining an ethylene glycol solution containing crude BHET requires multiple processing steps such as pre-depolymerization, depolymerization, removal of solid foreign matter, decolorization of activated carbon, deionization using ion exchange resin, crystallization and solid-liquid separation.
- This patent is made from waste
- the entire process from polyester to obtaining high-purity BHET is not only complex, has a long cycle, but also consumes a lot of energy (for example: the process requires the use of ethylene glycol that is at least 5 times the mass of waste polyester, otherwise the entire system will become hard.
- the purpose of the present invention is to provide a process and system for the continuous preparation of high-purity BHET monomer from waste polyester.
- a process for continuously preparing high-purity BHET monomer from waste polyester including the following specific steps:
- the decolorized alcoholysis product is input into the first thin film evaporator, and is subjected to a thin film evaporation treatment at 140°C to 180°C and a pressure of 100Pa to 1000Pa;
- melt obtained by secondary thin film evaporation is input into a molecular distiller, and molecular distillation is performed at 190°C to 250°C and a pressure of 1Pa to 100Pa;
- the high-purity BHET monomer melt with HPLC purity > 99.0% can be collected from the light component outlet of the molecular distiller, and the remaining distillation residue is input from the heavy component outlet of the molecular distiller and returned to the first Cyclic alcoholysis is carried out in the alcoholysis kettle.
- the pretreatment described in step A) refers to crushing, washing and drying the waste PET polyester to a moisture content of 1% to 3%.
- the alcoholysis catalyst described in step B) is zinc acetate.
- the time of the primary alcoholysis reaction described in step B) is equal to the time of the secondary alcoholysis reaction.
- the time of the primary alcoholysis reaction and the time of the secondary alcoholysis reaction described in step B) are both 15 min to 20 min.
- step C is to first cool the alcoholysis product to 140°C to 180°C, and then send it to an activated carbon adsorption device for decolorization.
- a system for continuously preparing high-purity BHET monomer from waste polyester including a screw extruder, a first alcoholysis kettle, a second alcoholysis kettle, an activated carbon adsorption device, a first thin film evaporator, and a second thin film evaporator and a molecular distiller, the discharge port of the screw extruder is connected to the feed port of the first alcoholysis kettle through a pipeline, and the discharge port of the first alcoholysis kettle is connected to the second alcoholysis kettle through a pipeline.
- the feed port of the alcoholysis kettle is connected, the discharge port of the second alcoholysis kettle is connected to the feed port of the activated carbon adsorption device through a pipeline, and the discharge port of the activated carbon adsorption device is connected to the first through a pipeline.
- the feed port of the thin film evaporator is connected to the feed port of the first thin film evaporator through a pipe, and the feed port of the second thin film evaporator is connected to the feed port of the second thin film evaporator through a pipe.
- the feed port of the molecular distiller is connected, and the heavy component discharge port of the molecular distiller is connected to the return port of the first alcoholysis kettle through a pipeline; and, the discharge port of the screw extruder is connected to
- a first melt filter is connected in series to the pipe between the feed inlet of the first alcoholysis kettle, and a pipe is connected in series between the outlet of the second alcoholysis kettle and the feed inlet of the activated carbon adsorption device. Second melt filter.
- the system further includes a waste polyester feeding bin, and the outlet of the waste polyester feeding bin is connected to the feed port of the screw extruder through a pipeline.
- a first delivery pump is connected in series to the pipeline between the first melt filter and the feed port of the first alcoholysis kettle, and the discharge port of the first alcoholysis kettle is connected to the second alcoholysis kettle.
- a second delivery pump is connected in series to the pipeline between the feed inlets of the kettle.
- a third delivery pump is connected in series to the pipeline between the outlet of the second alcoholysis kettle and the second melt filter.
- an alcoholysis product transfer tank is connected in series to the pipeline between the second melt filter and the feed port of the activated carbon adsorption device.
- a fourth delivery pump is connected in series to the pipeline between the outlet of the alcoholysis product transfer tank and the inlet of the activated carbon adsorption device.
- a first thin film evaporation product transfer tank is connected in series to the pipeline between the discharge port of the first thin film evaporator and the feed port of the second thin film evaporator.
- a fifth delivery pump is connected in series to the pipeline between the outlet of the first thin film evaporation product transfer tank and the feed inlet of the second thin film evaporator.
- a second thin film evaporation product transfer tank is connected in series to the pipeline between the outlet of the second thin film evaporator and the feed inlet of the molecular distiller.
- a sixth delivery pump is connected in series to the pipeline between the outlet of the second thin film evaporation product transfer tank and the feed inlet of the molecular distiller.
- a BHET monomer melt collection and insulation tank is connected in series to the light component outlet of the molecular distiller.
- a BHET monomer melt delivery pump is connected in series to the outlet of the BHET monomer melt collection insulation tank.
- a seventh delivery pump is connected in series to the pipeline between the heavy component discharge port of the molecular distiller and the return port of the first alcoholysis kettle.
- the present invention has the following beneficial effects:
- the present invention melts and pre-alcoholizes waste polyester materials with a small amount of ethylene glycol in a screw extruder at a certain temperature.
- the present invention improves the alcoholysis reaction by improving the alcoholysis reaction.
- the present invention can realize complete closed-loop recycling of waste PET polyester, which is of great significance and value for saving resources, reducing pollution and reducing carbon, and realizing the true regeneration and recycling of waste PET polyester.
- Figure 1 is a schematic structural diagram of a system for continuously preparing high-purity BHET monomer from waste polyester provided in Embodiment 1 of the present invention.
- the waste polyester described in the present invention includes but is not limited to polyester production waste and discarded polyester products.
- the polyester products include but is not limited to PET bottles, PET packaging sheets, PET fibers, PET textiles and PET foams. Foam.
- HPLC analysis conditions for the content and purity of BHET monomer are as follows:
- Agilent-1100 high performance liquid chromatograph the column specifications are Benetnach C18, 5 ⁇ m, 4.6*150mm, the solvent is acetonitrile, the detection wavelength is 254nm, the mobile phase is acetonitrile-water (70:30, V/V), and the flow rate is 0.5mL/min, The injection volume is 20 ⁇ L.
- This embodiment provides a system for continuously preparing high-purity BHET monomer from waste polyester, including a screw extruder 01, a first alcoholysis kettle 02, and a second alcoholysis kettle 03. , activated carbon adsorption device 04, first thin film evaporator 05, second thin film evaporator 06 and molecular distiller 07, the outlet of the screw extruder 01 is connected to the feed of the first alcoholysis kettle 02 through a pipeline The outlet of the first alcoholysis kettle 02 is connected to the feed inlet of the second alcoholysis kettle 03 through a pipeline, and the outlet of the second alcoholysis kettle 03 is connected to the activated carbon through a pipeline.
- the feed port of the adsorption device 04 is connected to the feed port of the activated carbon adsorption device 04 through a pipeline.
- the feed port of the first thin film evaporator 05 is connected to the feed port of the first thin film evaporator 05 through a pipeline. It is connected to the feed port of the second thin film evaporator 06, and the outlet of the second thin film evaporator 06 is connected to the feed port of the molecular distiller 07 through a pipeline.
- the reorganization of the molecular distiller 07 The outlet 07-1 is connected to the return port 02-1 of the first alcoholysis kettle 02 through a pipeline; and, the outlet of the screw extruder 01 is connected to the feed inlet of the first alcoholysis kettle 02.
- a first melt filter 08 is connected in series on the pipeline between them, and a second melt filter is connected in series on the pipeline between the outlet of the second alcoholysis kettle 03 and the inlet of the activated carbon adsorption device 04 09.
- the system also includes a waste polyester feeding bin 10.
- the outlet of the waste polyester feeding bin 10 is connected to the feed port of the screw extruder 01 through a pipeline;
- a first delivery pump 11 is connected in series to the pipeline between the first melt filter 08 and the feed port of the first alcoholysis kettle 02, and between the outlet of the first alcoholysis kettle 02 and the second alcoholysis kettle
- a second delivery pump 12 is connected in series on the pipeline between the feed ports of 03, and a third delivery pump is connected in series on the pipeline between the outlet of the second alcoholysis kettle 03 and the second melt filter 09. 13;
- An alcoholysis product transfer tank 14 is connected in series to the pipeline between the second melt filter 09 and the inlet of the activated carbon adsorption device 04.
- the outlet of the alcoholysis product transfer tank 14 is connected to the inlet of the activated carbon adsorption device 04.
- a fourth delivery pump 15 is connected in series to the pipeline between the material ports;
- a first thin film evaporation product transfer tank 16 is connected in series to the pipeline between the outlet of the first thin film evaporator 05 and the inlet of the second thin film evaporator 06.
- the outlet of the first thin film evaporation product transfer tank 16 is
- a fifth delivery pump 17 is connected in series to the pipeline between the feed port and the feed port of the second thin film evaporator 06;
- a second thin film evaporation product transfer tank 18 is connected in series to the pipeline between the outlet of the second thin film evaporator 06 and the feed inlet of the molecular distiller 07.
- the outlet of the second thin film evaporation product transfer tank 18 is connected in series.
- a sixth delivery pump 19 is connected in series to the pipeline between the feed port of the molecular distiller 07;
- the light component outlet 07-2 of the molecular distiller 07 is connected in series with the collection and insulation tank 20 of the BHET monomer melt, and the outlet of the BHET monomer melt collection insulation tank 20 is connected in series with the BHET monomer.
- the melt transfer pump 21 is connected in series with a seventh transfer pump 22 on the pipeline between the heavy component discharge port 07-1 of the molecular distiller 07 and the return port 02-1 of the first alcoholysis kettle 02.
- the system described in this example is used to realize the process of continuously preparing high-purity BHET monomer from waste polyester, including the following specific steps:
- This embodiment takes zinc acetate as an example), and performs primary alcoholization at 220°C to 260°C (this embodiment takes 240°C as an example) and the pressure in the kettle is 0.1MPa to 0.5MPa (this embodiment takes 0.2MPa as an example)
- the second transfer pump 12 is input into the second alcoholysis kettle 03, and continues to be heated at 220°C to 260°C (this embodiment takes 240°C as an example) and the kettle
- the secondary alcoholysis reaction is carried out under an internal pressure of 0.1MPa to 0.5MPa (0.2MPa is used as an example in this example) for 5min to 30min (20min is used as an example in this example);
- the alcoholysis product after decolorization is input into the first thin film evaporator 05, at a temperature of 140°C to 180°C (this embodiment takes 160°C as an example) and a pressure of 100Pa to 1000Pa (this embodiment takes 600Pa as an example) Perform a thin film evaporation treatment to remove most of the ethylene glycol and low-boiling substances in the alcoholysis product.
- the ethylene glycol and low-boiling substances can be collected and condensed through the condenser for reuse;
- the remaining alcoholysis products after one thin film evaporation treatment are first collected in the first thin film evaporation product transfer tank 16, and then fed into the second thin film evaporator 06 by the fifth transfer pump 17, at 140°C to 180°C (this The embodiment takes 160° C. as an example) and a pressure of 10 Pa to 100 Pa (this embodiment takes 50 Pa as an example) to perform a secondary thin film evaporation treatment to further remove ethylene glycol and ethylene glycol in the remaining alcoholysis product after the primary thin film evaporation treatment.
- Low boilers, ethylene glycol and low boilers can be condensed The condenser is collected and reused;
- the melt obtained by the secondary thin film evaporation treatment is first collected in the second thin film evaporation product transfer tank 18, and then is input into the molecular distiller 07 by the sixth transfer pump 19, and is heated at 190°C to 250°C (in this embodiment, Molecular distillation is carried out at 220°C as an example) and a pressure of 1Pa to 100Pa (20Pa as an example in this example);
- the purified high-purity BHET monomer vaporizes from the evaporation surface and condenses into a liquid on the condenser built in the molecular still through a short stroke.
- the component discharge port 07-2 enters the BHET monomer melt collection and insulation tank 20 for storage, and can be further transported to the subsequent esterification or polycondensation reaction kettle by the BHET monomer melt delivery pump 21 to directly participate in the downstream esterification or polycondensation reaction; the remaining distillation residue will flow into the heavy component outlet 07-1 of the molecular distiller 07 along the evaporation surface, and will be transported back to the first alcoholysis kettle 02 by the seventh delivery pump 22. Carry out cyclic alcoholysis.
- the pretreatment described in step A) refers to crushing, washing and drying the waste PET polyester to a moisture content of 1% to 3%.
- step A This example is for investigation: only in step A), the amount of ethylene glycol injected into the screw extruder 01 is different (please refer to Table 1 for details), and the other conditions are the same as those described in step A) of Example 1. Under the same circumstances, the influence on the intrinsic viscosity of the pre-alcohololysis solution output by screw extruder 01 is shown in Table 1 for the specific test results.
- the waste polyester can be made in Pre-alcoholization occurs at 220°C ⁇ 280°C, which can reduce the intrinsic viscosity of the waste polyester melt from 0.6 ⁇ 0.8dL/g (when the ethylene glycol addition amount is 0) to 0.3 ⁇ 0.4dL/g.
- step A) process of the present invention is not only conducive to continuous feeding, but also conducive to realizing that the waste polyester pre-alcohololysis melt can subsequently be in a homogeneous state with the ethylene glycol solvent.
- Alcoholysis reaction occurs in the system, It has a significant promoting effect on increasing the alcoholysis reaction rate and shortening the alcoholysis reaction time.
- step B This example is to investigate: in step B), if different alcoholysis conditions are used (for details, please refer to Table 2), and the other contents are the same as described in Example 1, the alcoholysis side reactions and The impact of BHET monomer purification, please see Table 2 for specific results.
- the present invention first processes waste polyester materials in a screw extruder with a small amount of ethylene glycol at a certain temperature.
- the occurrence of side reactions can be further suppressed, which is conducive to continuous production and high yield to obtain high-purity BHET monomer; in addition, in the entire process of the present invention, there is no need to repeat large-scale heating and cooling processes, and the obtained high-purity BHET
- the monomer is in a molten state and can be continuously fed for subsequent esterification or polycondensation reactions, which is of significant value to realize its downstream continuous application and reduce energy consumption.
- the present invention can realize complete closed-loop recycling of waste PET polyester, which is of great significance and value for saving resources, reducing pollution and reducing carbon, and realizing the true regeneration and recycling of waste PET polyester.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Crystallography & Structural Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Polyesters Or Polycarbonates (AREA)
Abstract
一种实现由废旧聚酯连续化制备高纯BHET单体的工艺及系统，所述工艺包括先使废旧聚酯在螺杆挤出机中进行螺杆挤压熔融和预醇解，然后进行一次醇解反应和二次醇解反应，再对醇解产物进行两次薄膜蒸发处理后进行分子蒸馏，从而得到高纯BHET单体熔体；所述系统包括螺杆挤出机、第一醇解釜、第二醇解釜、活性炭吸附装置、第一薄膜蒸发器、第二薄膜蒸发器、分子蒸馏器及第一熔体过滤器和第二熔体过滤器。所述工艺和系统能实现由废旧聚酯连续化制备高纯BHET单体，具有操作简单、易于实现自动化的优点，所需的乙二醇溶剂少、并能实现闭环回收再利用，具有能耗低、成本可显著降低等优点。
Description
本发明是涉及一种实现由废旧聚酯连续化制备高纯BHET单体的工艺及系统，属于废旧聚酯回收利用技术领域。
聚酯(即：聚对苯二甲酸乙二醇酯)因其具有良好的物理化学性能，已被广泛用于食品包装、薄膜片材、电子器件、机械设备等领域。据统计，2008年我国已成为世界聚酯生产、消费的第一大国，产量占全球一半以上，2015年我国聚酯的产量已达3530万吨，2019年我国聚酯的产量就已达到5006万吨，增幅达到41.8％。而聚酯产品大部分在一次使用后即变为废品，因此，随着聚酯产业的迅猛发展，废旧聚酯的产量也与日俱增。但聚酯具有很强的化学惰性，自然存放很难降解或被微生物分解，不仅造成了巨大的资源浪费，而且产生了严重的环境污染，因而如何实现废旧聚酯的回收和再利用的良性循环，已经成为当前聚酯工业发展不可回避和亟待解决的重要课题。
而理论上，BHET(即：对苯二甲酸乙二醇酯，其CAS号为959-26-2)可经缩聚反应直接得到聚对苯二甲酸乙二醇酯(即：PET)，因此，若能实现由废旧聚酯制得高纯度的BHET单体，将可通过进一步缩聚反应制得再生聚酯，从而真正实现废旧PET聚酯的循环再生。但废旧PET聚酯来源复杂，有色PET聚酯原料会导致解聚产物BHET颜色深，进而导致再生聚酯的再应用等级受到局限，成为乙二醇醇解回收PET聚酯的一大瓶颈问题；另外，又因为BHET的沸点高(432.1℃)且具有活性基团(羟基)，因此，在采用乙二醇解聚废旧聚酯时，容易发生乙二醇自缩合生成二乙二醇(以下简称DEG)的副产物及进一步发生由DEG与BHET发生酯交换反应生成对苯二甲酸-2-羟乙基酯(以下简称DEG酯)的副产物，而DEG或DEG酯的特性与EG或BHET很相近，极难与BHET相分离，以致不能制得高纯度的BHET单体。虽然申请号为201810921762.3的中国发明专利申请中，公开了采用重结晶和活性炭脱色对粗制的BHET进行提纯处理，即：先向经减压蒸馏后的粗制BHET中加入90℃热水，热水用量为减压蒸馏后醇解液质量的200％，之后搅拌过滤重复水洗3～5次，然后经活性炭脱色、过滤，将脱色后的滤液冷却至40℃使BHET结晶析出，可得到精制的BHET；但这种纯化处理方法不仅会产生较多废水和废乙二醇，导致废液处理压力大，而且存在热过滤困难(易堵
塞过滤器)、活性炭脱色和降温析出时间长、烘干困难等诸多操作上的难题，不仅致使所得BHET的色度和纯度均不能满足制备高质量PET产品的需求，而且也无法实现连续化生产；虽然专利号为200510097626.X的中国发明专利中公开了对含有粗BHET的乙二醇溶液经过2次蒸发处理后进行分子蒸馏处理，可得到高纯度的BHET，但该专利由废旧聚酯至获得含有粗BHET的乙二醇溶液，需要经过预解聚、解聚、固体异物的除去、活性炭脱色、利用离子交换树脂脱离子、晶析和固液分离等多个处理工序，该专利由废旧聚酯至得到高纯度的BHET的整个工艺，不仅工艺复杂，周期长，而且能耗大(如：该工艺需要使用至少为废旧聚酯质量5倍多的乙二醇，否则整个体系将呈硬块状或硬膏状，将无法进行后续的晶析和固液分离处理；另外，在解聚工序，需要从常温升温到250℃，到晶析工序，又需要降温至5℃，然后又要升温到150℃进行蒸发，在5～250℃之间需要来回升温、降温、升温处理，以致能耗很大)，关键是，该工艺也无法实现连续化生产，例如：在蒸发纯化前需要先进行低温晶析，且晶析得到的BHET呈稀泥状，以致在固液分离处理时需要压滤机进行压滤，不仅容易出现滤网堵塞需频繁更换滤布的情形，也导致不能实现连续化生产。
发明内容
针对现有技术存在的上述问题，本发明的目的是提供一种实现由废旧聚酯连续化制备高纯BHET单体的工艺及系统。
为实现上述发明目的，本发明采用的技术方案如下：
一种实现由废旧聚酯连续化制备高纯BHET单体的工艺，包括如下具体步骤：
A)使经预处理后的废旧聚酯注入螺杆挤出机中，同时注入为废旧聚酯质量的0.1％～5％(以0.5％～2.5％较佳)的乙二醇，在220℃～280℃下进行螺杆挤压熔融和预醇解；
B)由螺杆挤出机输出的预醇解液经滤除固体后输入第一醇解釜中，同时向第一醇解釜中加入为废旧聚酯质量1～3倍的乙二醇和为废旧聚酯质量的0.1‰～1‰(以0.4‰～0.8‰较佳)的醇解催化剂，在220℃～260℃及釜内压力为0.1MPa～0.5MPa下进行一次醇解反应5min～30min后，输入第二醇解釜中，继续在220℃～260℃及釜内压力为0.1MPa～0.5MPa下进行二次醇解反应5min～30min；
C)经二次醇解后的醇解产物经滤除固体后送入活性炭吸附装置进行脱色处理；
D)经脱色处理后的醇解产物输入第一薄膜蒸发器中，于140℃～180℃及压力为100Pa～1000Pa下进行一次薄膜蒸发处理；
E)经一次薄膜蒸发处理后的剩余醇解产物输入第二薄膜蒸发器中，于140℃～180℃及压力为10Pa～100Pa下进行二次薄膜蒸发处理；
F)经二次薄膜蒸发处理得到的熔体输入分子蒸馏器中，于190℃～250℃及压力为1Pa～100Pa下进行分子蒸馏处理；
G)由分子蒸馏器的轻组分出料口能收集得到HPLC纯度＞99.0％的高纯BHET单体熔体，剩余的蒸馏残留物由分子蒸馏器的重组分出料口输入返回至第一醇解釜中进行循环醇解。
一种实施方案，步骤A)中所述的预处理是指对废旧PET聚酯进行粉碎、水洗和干燥至含水率为1％～3％。
一种优选方案，步骤B)中所述的醇解催化剂为乙酸锌。
一种优选方案，步骤B)中所述的一次醇解反应的时间与二次醇解反应的时间等同。
进一步优选方案，步骤B)中所述的一次醇解反应的时间和二次醇解反应的时间均为15min～20min。
一种优选方案，步骤C)，先使醇解产物降温至140℃～180℃，然后送入活性炭吸附装置进行脱色处理。
一种实现由废旧聚酯连续化制备高纯BHET单体的系统，包括螺杆挤出机、第一醇解釜、第二醇解釜、活性炭吸附装置、第一薄膜蒸发器、第二薄膜蒸发器和分子蒸馏器，所述螺杆挤出机的出料口通过管道与所述第一醇解釜的进料口相连，所述第一醇解釜的出料口通过管道与所述第二醇解釜的进料口相连，所述第二醇解釜的出料口通过管道与所述活性炭吸附装置的进料口相连，所述活性炭吸附装置的出料口通过管道与所述第一薄膜蒸发器的进料口相连，所述第一薄膜蒸发器的出料口通过管道与所述第二薄膜蒸发器的进料口相连，所述第二薄膜蒸发器的出料口通过管道与所述分子蒸馏器的进料口相连，所述分子蒸馏器的重组分出料口通过管道与所述第一醇解釜的回料口相连；并且，在螺杆挤出机的出料口与第一醇解釜的进料口之间的管道上串接有第一熔体过滤器，在第二醇解釜的出料口与活性炭吸附装置的进料口之间的管道上串接有第二熔体过滤器。
一种优选方案，所述系统还包括废旧聚酯上料仓，所述废旧聚酯上料仓的出料口通过管道与所述螺杆挤出机的进料口相连。
一种优选方案，在第一熔体过滤器与第一醇解釜的进料口之间的管道上串接有第一输送泵，在第一醇解釜的出料口与第二醇解釜的进料口之间的管道上串接有第二输送泵，在
第二醇解釜的出料口与第二熔体过滤器之间的管道上串接有第三输送泵。
一种优选方案，在第二熔体过滤器与活性炭吸附装置的进料口之间的管道上串接有醇解产物中转罐。
进一步优选方案，在醇解产物中转罐的出料口与活性炭吸附装置的进料口之间的管道上串接有第四输送泵。
一种优选方案，在第一薄膜蒸发器的出料口与第二薄膜蒸发器的进料口之间的管道上串接有第一薄膜蒸发产物中转罐。
进一步优选方案，在第一薄膜蒸发产物中转罐的出料口与第二薄膜蒸发器的进料口之间的管道上串接有第五输送泵。
一种优选方案，在第二薄膜蒸发器的出料口与分子蒸馏器的进料口之间的管道上串接有第二薄膜蒸发产物中转罐。
进一步优选方案，在第二薄膜蒸发产物中转罐的出料口与分子蒸馏器的进料口之间的管道上串接有第六输送泵。
一种优选方案，在分子蒸馏器的轻组分出料口串接有BHET单体熔体的收集保温罐。
进一步优选方案，在BHET单体熔体的收集保温罐的出料口串接有BHET单体熔体的输送泵。
一种优选方案，在分子蒸馏器的重组分出料口与第一醇解釜的回料口之间的管道上串接有第七输送泵。
与现有技术相比，本发明具有如下有益效果：
通过采用本发明所述工艺和系统，不仅能实现由废旧聚酯连续化制备高纯BHET单体，具有操作简单、易于实现自动化的优点，而且所需的乙二醇溶剂少、并能实现闭环回收再利用，具有能耗低、成本可显著降低的优点，尤其是，本发明通过使废旧聚酯物料在螺杆挤出机中与少量乙二醇在一定温度下先进行熔融和预醇解，不仅实现了连续进料，而且保证了在降低醇解催化剂用量下仍能实现醇解，进而保证了对醇解催化剂所导致的自缩聚副反应的有效抑制；同时，本发明通过提升醇解反应温度和压力，有效解决了因醇解催化剂用量降低对醇解反应速率的影响问题，保证了醇解可在短时间内快速完成，进而也可进一步抑制副反应的发生，有利于连续化生产和高产率得到高纯BHET单体；另外，本发明整个工艺中，不需要反复大幅度升温和降温过程，且所得高纯BHET单体是熔融态，可进一步连续进料进行后续的酯化或缩聚反应，对实现其下游连续化应用及降低能耗均具有显著
价值。
总之，本发明能实现废旧PET聚酯完全闭环回收利用，对节约资源、减污降碳、实现废旧PET聚酯真正意义上的再生循环利用具有重要意义和价值。
图1为本发明实施例1提供的一种实现由废旧聚酯连续化制备高纯BHET单体的系统的结构示意图。
图中标号示意如下：
01、螺杆挤出机；02、第一醇解釜；02-1、回料口；03、第二醇解釜；04、活性炭吸附装置；05、第一薄膜蒸发器；06、第二薄膜蒸发器；07、分子蒸馏器；07-1、重组分出料口；07-2、轻组分出料口；08、第一熔体过滤器；09、第二熔体过滤器；10、废旧聚酯上料仓；11、第一输送泵；12、第二输送泵；13、第三输送泵；14、醇解产物中转罐；15、第四输送泵；16、第一薄膜蒸发产物中转罐；17、第五输送泵；18、第二薄膜蒸发产物中转罐；19、第六输送泵；20、BHET单体熔体的收集保温罐；21、BHET单体熔体的输送泵；22、第七输送泵。
下面结合实施例和附图及对比例，对本发明技术方案做进一步详细、完整地说明。应理解，下述实施例仅用于说明本发明而不用于限制本发明的范围。
下列实施例中未注明具体条件的实验方法，通常按照常规条件或按照制造厂商所建议的条件。
另外，需要理解的是，在本发明的描述中：
术语“第一”、“第二”、“第三”…等类似术语仅用于清晰描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。
本发明中所述的废旧聚酯包括但不限于聚酯生产废料和废弃的聚酯产品，所述的聚酯产品包括但不限于PET瓶、PET包装片材、PET纤维、PET纺织品和PET泡泡料。
下列实施例和对比例中，关于BHET单体的含量和纯度的HPLC分析条件如下：
Agilent-1100型高效液相色谱仪，色谱柱的规格为Benetnach C18、5μm、4.6*150mm，溶剂选择乙腈，检测波长254nm，流动相为乙腈-水(70:30，V/V)、流速为0.5mL/min，
进样量为20μL。
实施例1
请参阅图1所示，本实施例提供的一种实现由废旧聚酯连续化制备高纯BHET单体的系统，包括螺杆挤出机01、第一醇解釜02、第二醇解釜03、活性炭吸附装置04、第一薄膜蒸发器05、第二薄膜蒸发器06和分子蒸馏器07，所述螺杆挤出机01的出料口通过管道与所述第一醇解釜02的进料口相连，所述第一醇解釜02的出料口通过管道与所述第二醇解釜03的进料口相连，所述第二醇解釜03的出料口通过管道与所述活性炭吸附装置04的进料口相连，所述活性炭吸附装置04的出料口通过管道与所述第一薄膜蒸发器05的进料口相连，所述第一薄膜蒸发器05的出料口通过管道与所述第二薄膜蒸发器06的进料口相连，所述第二薄膜蒸发器06的出料口通过管道与所述分子蒸馏器07的进料口相连，所述分子蒸馏器07的重组分出料口07-1通过管道与所述第一醇解釜02的回料口02-1相连；并且，在螺杆挤出机01的出料口与第一醇解釜02的进料口之间的管道上串接有第一熔体过滤器08，在第二醇解釜03的出料口与活性炭吸附装置04的进料口之间的管道上串接有第二熔体过滤器09。
本实施例中：
所述系统还包括废旧聚酯上料仓10，所述废旧聚酯上料仓10的出料口通过管道与所述螺杆挤出机01的进料口相连；
在第一熔体过滤器08与第一醇解釜02的进料口之间的管道上串接有第一输送泵11，在第一醇解釜02的出料口与第二醇解釜03的进料口之间的管道上串接有第二输送泵12，在第二醇解釜03的出料口与第二熔体过滤器09之间的管道上串接有第三输送泵13；
在第二熔体过滤器09与活性炭吸附装置04的进料口之间的管道上串接有醇解产物中转罐14，在醇解产物中转罐14的出料口与活性炭吸附装置04的进料口之间的管道上串接有第四输送泵15；
在第一薄膜蒸发器05的出料口与第二薄膜蒸发器06的进料口之间的管道上串接有第一薄膜蒸发产物中转罐16，在第一薄膜蒸发产物中转罐16的出料口与第二薄膜蒸发器06的进料口之间的管道上串接有第五输送泵17；
在第二薄膜蒸发器06的出料口与分子蒸馏器07的进料口之间的管道上串接有第二薄膜蒸发产物中转罐18，在第二薄膜蒸发产物中转罐18的出料口与分子蒸馏器07的进料口之间的管道上串接有第六输送泵19；
在分子蒸馏器07的轻组分出料口07-2串接有BHET单体熔体的收集保温罐20，在BHET单体熔体的收集保温罐20的出料口串接有BHET单体熔体的输送泵21，在分子蒸馏器07的重组分出料口07-1与第一醇解釜02的回料口02-1之间的管道上串接有第七输送泵22。
采用本实施例所述的系统实现由废旧聚酯连续化制备高纯BHET单体的工艺，包括如下具体步骤：
A)使经预处理后的废旧聚酯由废旧聚酯上料仓10注入螺杆挤出机01中，同时向螺杆挤出机01中注入为废旧聚酯质量的0.1％～5％(本实施例以0.5％为例)的乙二醇，在220℃～280℃(本实施例以240℃为例)下进行螺杆挤压熔融和预醇解；
B)由螺杆挤出机01输出的预醇解液经第一熔体过滤器08滤除固体后由第一输送泵11输入第一醇解釜02中，同时向第一醇解釜02中加入为废旧聚酯质量1～3倍(本实施例以2倍为例)的乙二醇和为废旧聚酯质量的0.1‰～1‰(本实施例以0.5‰为例)的醇解催化剂(本实施例以乙酸锌为例)，在220℃～260℃(本实施例以240℃为例)及釜内压力为0.1MPa～0.5MPa(本实施例以0.2MPa为例)下进行一次醇解反应5min～30min(本实施例以20min为例)后，由第二输送泵12输入第二醇解釜03中，继续在220℃～260℃(本实施例以240℃为例)及釜内压力为0.1MPa～0.5MPa(本实施例以0.2MPa为例)下进行二次醇解反应5min～30min(本实施例以20min为例)；
C)经二次醇解后的醇解产物由第三输送泵13送入第二熔体过滤器09，醇解产物经第二熔体过滤器09滤除固体后送入醇解产物中转罐14，使醇解产物在醇解产物中转罐14中降温至140℃～180℃(本实施例以160℃为例)后，再由第四输送泵15送入活性炭吸附装置04中进行脱色处理；
D)经脱色处理后的醇解产物输入第一薄膜蒸发器05中，于140℃～180℃(本实施例以160℃为例)及压力为100Pa～1000Pa(本实施例以600Pa为例)下进行一次薄膜蒸发处理，以除去醇解产物中的大部分乙二醇和低沸物，乙二醇和低沸物可通过冷凝器收集冷凝后回用；
E)经一次薄膜蒸发处理后的剩余醇解产物先收集在第一薄膜蒸发产物中转罐16中，然后由第五输送泵17输入第二薄膜蒸发器06中，于140℃～180℃(本实施例以160℃为例)及压力为10Pa～100Pa(本实施例以50Pa为例)下进行二次薄膜蒸发处理，以进一步除去经一次薄膜蒸发处理后的剩余醇解产物中的乙二醇和低沸物，乙二醇和低沸物可通过冷凝
器收集冷凝后回用；
F)经二次薄膜蒸发处理得到的熔体先收集在第二薄膜蒸发产物中转罐18中，然后由第六输送泵19输入分子蒸馏器07中，于190℃～250℃(本实施例以220℃为例)及压力为1Pa～100Pa(本实施例以20Pa为例)下进行分子蒸馏处理；
G)在分子蒸馏器07中，被提纯的高纯BHET单体从蒸发面上气化并经经很短的行程在分子蒸馏器内置的冷凝器上冷凝成液体，由分子蒸馏器07的轻组分出料口07-2进入BHET单体熔体的收集保温罐20中储存，可进一步由BHET单体熔体的输送泵21输送给后续的酯化或缩聚反应釜中，以直接参与下游的酯化或缩聚反应；剩余的蒸馏残留物沿着蒸发面将流入分子蒸馏器07的重组分出料口07-1，并由第七输送泵22输送返回至第一醇解釜02中以进行循环醇解。
步骤A)中所述的预处理是指对废旧PET聚酯进行粉碎、水洗和干燥至含水率为1％～3％。
经对收集保温罐20中的BHET单体熔体取样分析，可知所获得的BHET单体熔体的HPLC纯度为99.1％。
实施例2
本实施例是考察：只是在步骤A)，向螺杆挤出机01中注入的乙二醇用量不同(具体请参阅表1所示)，而其余条件均与实施例1的步骤A)所述相同的情况下，对螺杆挤出机01输出的预醇解液的特性粘度的影响，具体测试结果请详见表1所示。
表1乙二醇用量对预醇解液的特性粘度的影响
由表1所示结果可见：在其余条件相同情况下，当向螺杆挤出机01中同时注入少量(优选为废旧聚酯质量的0.5％～2.5％)乙二醇，可使废旧聚酯在220℃～280℃下发生预醇解，能使废旧聚酯的熔体的特性粘度由0.6～0.8dL/g(乙二醇添加量为0时)下降到0.3～0.4dL/g，特性粘度下降了大约50％；由此可说明，采用本发明的步骤A)工艺，不仅有利于连续进料，而且有利于实现废旧聚酯预醇解熔体在后续能与乙二醇溶剂在均相体系中发生醇解反应，
对提升醇解反应速率、缩短醇解反应时间具有显著促进作用。
实施例3
本实施例是考察：在步骤B)，若采用不同的醇解条件(具体请参阅表2所示)，而其余内容均与实施例1中所述相同的情况下，对醇解副反应和BHET单体提纯的影响，具体结果请详见表2所示。
表2不同醇解条件对醇解副反应和BHET单体提纯的影响
由表2所示结果可见：对于相同的预醇解液，若采用现有的醇解条件(醇解催化剂用量为废旧聚酯质量的3‰，在197℃、常压下)进行醇解，醇解时间长，以致醇解产物中游离DEG的含量高达6.57％，且由实验观察可见：该醇解产物在分子蒸馏纯化过程中，会促使BHET熔体发生自缩聚生成BHET多聚体凝固在分子蒸馏器中，造成管道堵塞，致使连续蒸馏生产被迫终止，不能继续实现连续化生产，以致最终只能获得产率只有23.6％的高纯BHET单体；而采用本发明所述醇解条件(醇解催化剂用量为废旧聚酯质量的0.4‰～0.8‰，在220℃～260℃及釜内压力为0.1MPa～0.5MPa下)，不仅可显著缩短醇解反应时间(只需30～40分钟)，使醇解产物中游离DEG的含量小于2％，而且能获得产率高达78％、纯度高达99％的高纯BHET单体，并能正常实现连续化生产。
由上所述可见：通过采用本发明所述工艺和系统，不仅能实现由废旧聚酯连续化制备高纯BHET单体，具有操作简单、易于实现自动化的优点，而且所需的乙二醇溶剂少、并能实现闭环回收再利用，具有能耗低、成本可显著降低的优点，尤其是，本发明通过使废旧聚酯物料在螺杆挤出机中与少量乙二醇在一定温度下先进行熔融和预醇解，不仅实现了连续进料，而且保证了在降低醇解催化剂用量下仍能实现醇解，进而保证了对醇解催化剂所导致的自缩聚副反应的有效抑制；同时，本发明通过提升醇解反应温度和压力，有效解决了因醇解催化剂用量降低对醇解反应速率的影响问题，保证了醇解可在短时间内快速完
成，进而也可进一步抑制副反应的发生，有利于连续化生产和高产率得到高纯BHET单体；另外，本发明整个工艺中，不需要反复大幅度升温和降温过程，且所得高纯BHET单体是熔融态，可进一步连续进料进行后续的酯化或缩聚反应，对实现其下游连续化应用及降低能耗均具有显著价值。总之，本发明能实现废旧PET聚酯完全闭环回收利用，对节约资源、减污降碳、实现废旧PET聚酯真正意义上的再生循环利用具有重要意义和价值。
最后需要在此指出的是：以上仅是本发明的部分优选实施例，不能理解为对本发明保护范围的限制，本领域的技术人员根据本发明的上述内容做出的一些非本质的改进和调整均属于本发明的保护范围。
Claims (10)
- 一种实现由废旧聚酯连续化制备高纯BHET单体的工艺，其特征在于，包括如下具体步骤：A)使经预处理后的废旧聚酯注入螺杆挤出机中，同时注入为废旧聚酯质量的0.1％～5％的乙二醇，在220℃～280℃下进行螺杆挤压熔融和预醇解；B)由螺杆挤出机输出的预醇解液经滤除固体后输入第一醇解釜中，同时向第一醇解釜中加入为废旧聚酯质量1～3倍的乙二醇和为废旧聚酯质量的0.1‰～1‰的醇解催化剂，在220℃～260℃及釜内压力为0.1MPa～0.5MPa下进行一次醇解反应5min～30min后，输入第二醇解釜中，继续在220℃～260℃及釜内压力为0.1MPa～0.5MPa下进行二次醇解反应5min～30min；C)经二次醇解后的醇解产物经滤除固体后送入活性炭吸附装置进行脱色处理；D)经脱色处理后的醇解产物输入第一薄膜蒸发器中，于140℃～180℃及压力为100Pa～1000Pa下进行一次薄膜蒸发处理；E)经一次薄膜蒸发处理后的剩余醇解产物输入第二薄膜蒸发器中，于140℃～180℃及压力为10Pa～100Pa下进行二次薄膜蒸发处理；F)经二次薄膜蒸发处理得到的熔体输入分子蒸馏器中，于190℃～250℃及压力为1Pa～100Pa下进行分子蒸馏处理；G)由分子蒸馏器的轻组分出料口能收集得到HPLC纯度＞99.0％的高纯BHET单体熔体，剩余的蒸馏残留物由分子蒸馏器的重组分出料口输入返回至第一醇解釜中进行循环醇解。
- 根据权利要求1所述的工艺，其特征在于：步骤C)，先使醇解产物降温至140℃～180℃，然后送入活性炭吸附装置进行脱色处理。
- 一种实现由废旧聚酯连续化制备高纯BHET单体的系统，其特征在于：包括螺杆挤出机、第一醇解釜、第二醇解釜、活性炭吸附装置、第一薄膜蒸发器、第二薄膜蒸发器和分子蒸馏器，所述螺杆挤出机的出料口通过管道与所述第一醇解釜的进料口相连，所述第一醇解釜的出料口通过管道与所述第二醇解釜的进料口相连，所述第二醇解釜的出料口通过管道与所述活性炭吸附装置的进料口相连，所述活性炭吸附装置的出料口通过管道与所述第一薄膜蒸发器的进料口相连，所述第一薄膜蒸发器的出料口通过管道与所述第二薄膜蒸发器的进料口相连，所述第二薄膜蒸发器的出料口通过管道与所述分子蒸馏器的进料口相连，所述分子蒸馏器的重组分出料口通过管道与所述第一醇解釜的回料口相连；并且， 在螺杆挤出机的出料口与第一醇解釜的进料口之间的管道上串接有第一熔体过滤器，在第二醇解釜的出料口与活性炭吸附装置的进料口之间的管道上串接有第二熔体过滤器。
- 根据权利要求3所述的系统，其特征在于：所述系统还包括废旧聚酯上料仓，所述废旧聚酯上料仓的出料口通过管道与所述螺杆挤出机的进料口相连。
- 根据权利要求3所述的系统，其特征在于：在第一熔体过滤器与第一醇解釜的进料口之间的管道上串接有第一输送泵，在第一醇解釜的出料口与第二醇解釜的进料口之间的管道上串接有第二输送泵，在第二醇解釜的出料口与第二熔体过滤器之间的管道上串接有第三输送泵。
- 根据权利要求3所述的系统，其特征在于：在第二熔体过滤器与活性炭吸附装置的进料口之间的管道上串接有醇解产物中转罐，在醇解产物中转罐的出料口与活性炭吸附装置的进料口之间的管道上串接有第四输送泵。
- 根据权利要求3所述的系统，其特征在于：在第一薄膜蒸发器的出料口与第二薄膜蒸发器的进料口之间的管道上串接有第一薄膜蒸发产物中转罐，在第一薄膜蒸发产物中转罐的出料口与第二薄膜蒸发器的进料口之间的管道上串接有第五输送泵。
- 根据权利要求3所述的系统，其特征在于：在第二薄膜蒸发器的出料口与分子蒸馏器的进料口之间的管道上串接有第二薄膜蒸发产物中转罐，在第二薄膜蒸发产物中转罐的出料口与分子蒸馏器的进料口之间的管道上串接有第六输送泵。
- 根据权利要求3所述的系统，其特征在于：在分子蒸馏器的轻组分出料口串接有BHET单体熔体的收集保温罐，在BHET单体熔体的收集保温罐的出料口串接有BHET单体熔体的输送泵。
- 根据权利要求3所述的系统，其特征在于：在分子蒸馏器的重组分出料口与第一醇解釜的回料口之间的管道上串接有第七输送泵。
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210610436.7 | 2022-05-31 | ||
| CN202210610436.7A CN117185931A (zh) | 2022-05-31 | 2022-05-31 | 一种实现由废旧聚酯连续化制备高纯bhet单体的工艺及系统 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2023231628A1 true WO2023231628A1 (zh) | 2023-12-07 |
Family
ID=89002192
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/CN2023/089358 WO2023231628A1 (zh) | 2022-05-31 | 2023-04-19 | 一种实现由废旧聚酯连续化制备高纯bhet单体的工艺及系统 |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN117185931A (zh) |
| WO (1) | WO2023231628A1 (zh) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040182782A1 (en) * | 2002-06-04 | 2004-09-23 | Shuji Inada | Processes for the purification of bis(2-hydroxyethyl)terephthalate |
| JP2004346229A (ja) * | 2003-05-23 | 2004-12-09 | Is:Kk | ポリエステルのエチレングリコール分解生成溶液の精製方法 |
| CN102532591A (zh) * | 2012-02-22 | 2012-07-04 | 中南大学 | 一种解聚废旧聚酯瓶的方法 |
| CN108641120A (zh) * | 2018-08-14 | 2018-10-12 | 上海聚友化工有限公司 | 一种废旧聚酯纺织品回收再利用的方法及其回收系统 |
| CN110527138A (zh) * | 2019-07-10 | 2019-12-03 | 艾凡佳德(上海)环保科技有限公司 | 一种废旧聚酯的连续醇解回收方法 |
| CN112646135A (zh) * | 2020-12-10 | 2021-04-13 | 北京服装学院 | 有色废旧聚酯纺织品连续制备可纺级无色再生聚酯的方法 |
| WO2022003084A1 (en) * | 2020-07-02 | 2022-01-06 | Cure Technology B.V. | A method to enable recycling of polyester waste material and a system for applying the method |
-
2022
- 2022-05-31 CN CN202210610436.7A patent/CN117185931A/zh active Pending
-
2023
- 2023-04-19 WO PCT/CN2023/089358 patent/WO2023231628A1/zh unknown
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040182782A1 (en) * | 2002-06-04 | 2004-09-23 | Shuji Inada | Processes for the purification of bis(2-hydroxyethyl)terephthalate |
| JP2004346229A (ja) * | 2003-05-23 | 2004-12-09 | Is:Kk | ポリエステルのエチレングリコール分解生成溶液の精製方法 |
| CN102532591A (zh) * | 2012-02-22 | 2012-07-04 | 中南大学 | 一种解聚废旧聚酯瓶的方法 |
| CN108641120A (zh) * | 2018-08-14 | 2018-10-12 | 上海聚友化工有限公司 | 一种废旧聚酯纺织品回收再利用的方法及其回收系统 |
| CN110527138A (zh) * | 2019-07-10 | 2019-12-03 | 艾凡佳德(上海)环保科技有限公司 | 一种废旧聚酯的连续醇解回收方法 |
| WO2022003084A1 (en) * | 2020-07-02 | 2022-01-06 | Cure Technology B.V. | A method to enable recycling of polyester waste material and a system for applying the method |
| CN112646135A (zh) * | 2020-12-10 | 2021-04-13 | 北京服装学院 | 有色废旧聚酯纺织品连续制备可纺级无色再生聚酯的方法 |
Also Published As
| Publication number | Publication date |
|---|---|
| CN117185931A (zh) | 2023-12-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US20210024718A1 (en) | Method for recycling waste polyester | |
| US11655351B2 (en) | Method for recycling waste polyester with continuous alcoholysis and transesterification | |
| CN102911396B (zh) | 一种废旧pet材料的回收工艺 | |
| CN111138641A (zh) | 一种废聚酯瓶回用制备瓶级切片的方法 | |
| CN104774153A (zh) | 一种催化降解废旧pet回收的方法 | |
| CN102746270B (zh) | 一种回收聚乳酸制备精制级丙交酯的方法 | |
| CN114656684A (zh) | 一种利用废旧pet聚酯制备高纯再生pet聚酯的方法 | |
| CN102126917B (zh) | 不同含量二氯甲烷废水的高纯回收与能量集成工艺 | |
| CN103723744A (zh) | 一种从脱硫废液或脱硫液混盐中提取高纯度硫氰酸钠的方法 | |
| WO2023231628A1 (zh) | 一种实现由废旧聚酯连续化制备高纯bhet单体的工艺及系统 | |
| CN102532591B (zh) | 一种解聚废旧聚酯瓶的方法 | |
| CN1908041A (zh) | 利用废旧abs塑料回收再生高纯度abs的生产方法 | |
| JP5178211B2 (ja) | ペットボトル廃棄物より色相を改善したテレフタル酸ジメチルを回収する方法 | |
| CN101177372A (zh) | 提纯制备精苊的方法 | |
| CN114773587A (zh) | 一种用于ppc生产过程中环氧丙烷脱除工艺 | |
| CN113968782A (zh) | 一种去除回收再利用醋酸中杂质的方法 | |
| CN217516872U (zh) | 一种由废旧聚酯制备再生聚酯的连续化生产系统 | |
| CN107129103B (zh) | 一种糠醛生产废水综合处理利用工艺与方法 | |
| CN202844611U (zh) | 氯乙酸母液回收的蒸馏装置系统 | |
| CN103086902B (zh) | 一种醇相体系生产甘氨酸的氨气回收方法 | |
| CN212741198U (zh) | 一种新型的粗聚乙烯蜡的精制装置 | |
| CN110845759B (zh) | 一种醇解液中过量二元醇的去除方法 | |
| KR20220139772A (ko) | 폴리에틸렌테레프탈레이트의 비스테레프탈레이트 분리 및 회수방법 | |
| CN118005527A (zh) | 一种甲酰胺生产废水的资源化处理方法 | |
| CN117263794A (zh) | 一种丁二酸提纯精制方法 |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 23814814 Country of ref document: EP Kind code of ref document: A1 |