CN115304454A - Separation method and system for recovering ethylene glycol in polyester production process - Google Patents
Separation method and system for recovering ethylene glycol in polyester production process Download PDFInfo
- Publication number
- CN115304454A CN115304454A CN202110495507.9A CN202110495507A CN115304454A CN 115304454 A CN115304454 A CN 115304454A CN 202110495507 A CN202110495507 A CN 202110495507A CN 115304454 A CN115304454 A CN 115304454A
- Authority
- CN
- China
- Prior art keywords
- ethylene glycol
- glycol
- tower
- separation
- crude
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 title claims abstract description 427
- 238000000926 separation method Methods 0.000 title claims abstract description 47
- 229920000728 polyester Polymers 0.000 title claims abstract description 41
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 24
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 claims abstract description 71
- 239000012535 impurity Substances 0.000 claims abstract description 43
- 239000002994 raw material Substances 0.000 claims abstract description 33
- 238000000034 method Methods 0.000 claims abstract description 32
- 238000006243 chemical reaction Methods 0.000 claims abstract description 20
- CLBRCZAHAHECKY-UHFFFAOYSA-N [Co].[Pt] Chemical compound [Co].[Pt] CLBRCZAHAHECKY-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000012752 auxiliary agent Substances 0.000 claims abstract description 17
- 239000000463 material Substances 0.000 claims abstract description 14
- 150000001263 acyl chlorides Chemical class 0.000 claims abstract description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 28
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 claims description 21
- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 claims description 20
- 230000008569 process Effects 0.000 claims description 20
- 239000000047 product Substances 0.000 claims description 19
- 229910052757 nitrogen Inorganic materials 0.000 claims description 14
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 claims description 12
- 238000010992 reflux Methods 0.000 claims description 10
- 229920001577 copolymer Polymers 0.000 claims description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- DLFVBJFMPXGRIB-UHFFFAOYSA-N Acetamide Chemical compound CC(N)=O DLFVBJFMPXGRIB-UHFFFAOYSA-N 0.000 claims description 8
- BGTOWKSIORTVQH-UHFFFAOYSA-N cyclopentanone Chemical compound O=C1CCCC1 BGTOWKSIORTVQH-UHFFFAOYSA-N 0.000 claims description 8
- KZNICNPSHKQLFF-UHFFFAOYSA-N succinimide Chemical compound O=C1CCC(=O)N1 KZNICNPSHKQLFF-UHFFFAOYSA-N 0.000 claims description 8
- -1 polyethylene terephthalate Polymers 0.000 claims description 7
- 229920000139 polyethylene terephthalate Polymers 0.000 claims description 7
- 239000005020 polyethylene terephthalate Substances 0.000 claims description 7
- ZIBGPFATKBEMQZ-UHFFFAOYSA-N triethylene glycol Chemical compound OCCOCCOCCO ZIBGPFATKBEMQZ-UHFFFAOYSA-N 0.000 claims description 7
- 239000004952 Polyamide Substances 0.000 claims description 6
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 claims description 6
- CTSLXHKWHWQRSH-UHFFFAOYSA-N oxalyl chloride Chemical compound ClC(=O)C(Cl)=O CTSLXHKWHWQRSH-UHFFFAOYSA-N 0.000 claims description 6
- 238000012856 packing Methods 0.000 claims description 6
- 229920002647 polyamide Polymers 0.000 claims description 6
- SXYFKXOFMCIXQW-UHFFFAOYSA-N propanedioyl dichloride Chemical compound ClC(=O)CC(Cl)=O SXYFKXOFMCIXQW-UHFFFAOYSA-N 0.000 claims description 5
- 230000035484 reaction time Effects 0.000 claims description 5
- VHGGRTWHRJRQKU-UHFFFAOYSA-N 1-methyl-2h-pyrrol-5-one Chemical compound CN1CC=CC1=O VHGGRTWHRJRQKU-UHFFFAOYSA-N 0.000 claims description 4
- HTWIZMNMTWYQRN-UHFFFAOYSA-N 2-methyl-1,3-dioxolane Chemical compound CC1OCCO1 HTWIZMNMTWYQRN-UHFFFAOYSA-N 0.000 claims description 4
- HVCNXQOWACZAFN-UHFFFAOYSA-N 4-ethylmorpholine Chemical compound CCN1CCOCC1 HVCNXQOWACZAFN-UHFFFAOYSA-N 0.000 claims description 4
- ZHNUHDYFZUAESO-OUBTZVSYSA-N aminoformaldehyde Chemical compound N[13CH]=O ZHNUHDYFZUAESO-OUBTZVSYSA-N 0.000 claims description 4
- UZBQIPPOMKBLAS-UHFFFAOYSA-N diethylazanide Chemical compound CC[N-]CC UZBQIPPOMKBLAS-UHFFFAOYSA-N 0.000 claims description 4
- ALBYIUDWACNRRB-UHFFFAOYSA-N hexanamide Chemical compound CCCCCC(N)=O ALBYIUDWACNRRB-UHFFFAOYSA-N 0.000 claims description 4
- KNCYXPMJDCCGSJ-UHFFFAOYSA-N piperidine-2,6-dione Chemical compound O=C1CCCC(=O)N1 KNCYXPMJDCCGSJ-UHFFFAOYSA-N 0.000 claims description 4
- 229960002317 succinimide Drugs 0.000 claims description 4
- KKFDCBRMNNSAAW-UHFFFAOYSA-N 2-(morpholin-4-yl)ethanol Chemical compound OCCN1CCOCC1 KKFDCBRMNNSAAW-UHFFFAOYSA-N 0.000 claims description 3
- JDTUPLBMGDDPJS-UHFFFAOYSA-N 2-methoxy-2-phenylethanol Chemical compound COC(CO)C1=CC=CC=C1 JDTUPLBMGDDPJS-UHFFFAOYSA-N 0.000 claims description 3
- IYLIUGUSZIJCKW-UHFFFAOYSA-N C=CC1=CC(=O)CN1 Chemical compound C=CC1=CC(=O)CN1 IYLIUGUSZIJCKW-UHFFFAOYSA-N 0.000 claims description 3
- IKHGUXGNUITLKF-XPULMUKRSA-N acetaldehyde Chemical compound [14CH]([14CH3])=O IKHGUXGNUITLKF-XPULMUKRSA-N 0.000 claims description 3
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 claims description 3
- 239000006227 byproduct Substances 0.000 claims description 2
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 claims description 2
- 150000001299 aldehydes Chemical class 0.000 claims 1
- 150000002576 ketones Chemical class 0.000 claims 1
- 238000002156 mixing Methods 0.000 abstract description 2
- 238000004064 recycling Methods 0.000 abstract description 2
- 238000009776 industrial production Methods 0.000 abstract 1
- 238000004458 analytical method Methods 0.000 description 11
- 230000015556 catabolic process Effects 0.000 description 11
- 238000006731 degradation reaction Methods 0.000 description 11
- 238000010168 coupling process Methods 0.000 description 8
- 230000001186 cumulative effect Effects 0.000 description 8
- 229920006149 polyester-amide block copolymer Polymers 0.000 description 8
- 239000000203 mixture Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 125000002485 formyl group Chemical class [H]C(*)=O 0.000 description 5
- 238000007670 refining Methods 0.000 description 5
- 229920000742 Cotton Polymers 0.000 description 4
- 239000000835 fiber Substances 0.000 description 4
- 238000011084 recovery Methods 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 230000032050 esterification Effects 0.000 description 3
- 238000005886 esterification reaction Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 229920000515 polycarbonate Polymers 0.000 description 3
- 239000004417 polycarbonate Substances 0.000 description 3
- 238000000746 purification Methods 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- IKHGUXGNUITLKF-UHFFFAOYSA-N Acetaldehyde Chemical compound CC=O IKHGUXGNUITLKF-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000010924 continuous production Methods 0.000 description 2
- 238000007334 copolymerization reaction Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- DZCBKUAAGVVLOX-UHFFFAOYSA-N 1-morpholin-4-ylethanol Chemical compound CC(O)N1CCOCC1 DZCBKUAAGVVLOX-UHFFFAOYSA-N 0.000 description 1
- FPNZGKGDOGMVHE-UHFFFAOYSA-N 5-ethenyl-2,3-dihydro-1h-pyrrole Chemical compound C=CC1=CCCN1 FPNZGKGDOGMVHE-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 125000003368 amide group Chemical group 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 150000003997 cyclic ketones Chemical class 0.000 description 1
- 239000007857 degradation product Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000006266 etherification reaction Methods 0.000 description 1
- 125000000623 heterocyclic group Chemical group 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000010525 oxidative degradation reaction Methods 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000007363 ring formation reaction Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Images
Classifications
-
- 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
- C07C29/88—Separation; Purification; Use of additives, e.g. for stabilisation by treatment giving rise to a chemical modification of at least one compound
-
- 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
- C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a separation method and a separation system for recovering ethylene glycol in a polyester production process. The separation method comprises the following steps: reacting the crude glycol raw material with an acyl chloride auxiliary agent to obtain a pretreated mixed material; and rectifying and separating the pretreated mixed material to obtain a light component, an ethylene glycol product and a heavy component. The separation system comprises a rectification system, wherein a raw material pre-reaction system is arranged in front of the rectification system, and the rectification system comprises a light component removal tower and a heavy component removal tower. The method solves the problems of high impurity content in the recovered glycol and high difficulty in conventional rectification separation in the polyester production process in the prior art, the obtained glycol product has high purity, the impurities which affect the platinum-cobalt thermal chromaticity are effectively removed, the recycling blending amount for polyester production is increased, and the method can be used in industrial production for purifying the recovered glycol.
Description
Technical Field
The invention relates to a separation method and a separation system for recovering ethylene glycol in a polyester production process.
Background
The super cotton-like polyester fiber is mainly polyester, the polyester content is more than 85 percent, and the polyester fiber is a differentiated functionalized polyester fiber which looks like cotton, feels like cotton, is worn like cotton and is more convenient than cotton in use. The super cotton-like polyester fiber is generally polyesteramide obtained by introducing a polymer with an amide group into the synthetic preparation process of polyester PET for copolymerization.
The production process of the polyesteramide comprises the following steps: certain amount of glycol, terephthalic acid and catalyst are firstly esterified in an esterification reactor, then certain amount of caprolactam or polyamide and auxiliary agent are added for copolymerization in a polymerization reactor, and the components of water, complex degradation products, unreacted glycol and the like generated in a polyester reactor are pumped out to a crude glycol storage tank through a vacuum system and recovered by a glycol refining system.
The processing method of crude glycol pumped out by a vacuum system at present mainly comprises the following steps:
1. no ethylene glycol recovery refining unit: patent CN1054988a discloses a method for continuous production of polyester by direct esterification, which does not have a recovery and refining device to recover and refine the excess glycol in the system, but directly returns the glycol condensed in the vacuum system to be used as raw material. The process can result in the accumulation of impurities in the system resulting from the degradation of the polyester, resulting in a decrease in the color of the polyester.
2. A single process tower is arranged for ethylene glycol refining: patent CN101575122a discloses a method for refining crude ethylene glycol by using a process tower and a stripping tower, wherein the refined ethylene glycol is obtained from the bottom of the process tower, water, aldehydes and other components are obtained from the top of the process tower, and then the stripping tower is used for treating wastewater. In the process, heavy component impurities generated by degradation cannot be separated, and the impurities are accumulated in a system, so that the chromaticity of the polyester is not up to the standard. The "transformation of esterification process tower", published in 2008, 2 nd 21 in the polyester industry, also recovers crude ethylene glycol through a single process tower, still causes the purity of refined ethylene glycol not to reach the standard.
It can be seen that the separation and purification of the recycled ethylene glycol in the production of polyesteramides is only in a simple rectification and separation stage. As the ethylene glycol component recovered in the preparation process of polyesteramide is more complex than that of the conventional polyester, industrial devices and small trial run research processes find that certain impurities which are difficult to separate by conventional rectification always exist in the product ethylene glycol, and the thermal chroma of the product ethylene glycol is difficult to reduce to the general use requirement of the polyester. Therefore, how to realize the separation of impurities and the reduction of thermal chroma by process innovation on the basis of the conventional rectification process is one of important problems to be solved urgently in large-scale continuous production of polyesters, particularly polyesteramides.
Disclosure of Invention
The invention aims to solve the technical problems that the content of impurities in the recovered glycol is high in the polyester production process in the prior art, and the conventional rectification separation difficulty is high, and provides a novel separation method and a novel separation system for recovering glycol in the polyester production process. The method can obviously improve the purity of the glycol product in the existing rectification separation process, reduce the heat chroma of the glycol product and improve the recycling and blending proportion of the glycol product.
The invention provides a separation method for recovering ethylene glycol in a polyester production process, which comprises the following steps:
s1, reacting a crude ethylene glycol raw material with an acyl chloride auxiliary agent to obtain a pretreated mixed material;
s2, rectifying and separating the pretreated mixed material to obtain a light component, an ethylene glycol product and a heavy component.
In the technical scheme, the polyester is polyethylene terephthalate, or a copolymer of polyethylene terephthalate and polyamide, or a copolymer of terephthalic acid, ethylene glycol and caprolactam.
In the above technical solution, the polyester is preferably a copolymer of polyethylene terephthalate and polyamide, or a copolymer of terephthalic acid, ethylene glycol and caprolactam.
In the above technical scheme, in the step S1, the raw material of the crude ethylene glycol is a raw material containing the crude ethylene glycol, and may be the crude ethylene glycol, or may be a mixture of the crude ethylene glycol and fresh ethylene glycol. The crude glycol is derived from a byproduct rich in glycol in the polyester production process, generally derived from a material rich in glycol pumped out by a vacuum system, or derived from a material rich in glycol primarily purified by a polyester process tower. The crude ethylene glycol comprises ethylene glycol and impurities, wherein the impurities comprise chain or cyclic aldehyde, chain or cyclic ketone, chain or cyclic nitrogen-containing impurities, and can also comprise other oxygen-containing impurities, such as oxygen-containing heterocycles, alcohols and the like. In the crude ethylene glycol raw material, the mass content of ethylene glycol is 75-95%. The platinum-cobalt thermal chroma of the crude glycol is more than 500Hazen. The content of the impurities is not less than 5ppm, preferably not less than 50ppm, more preferably not less than 100ppm, in terms of total nitrogen element.
In the above technical solution, the impurities include, but are not limited to, the following: water, acetaldehyde, N-ethylmorpholine, morpholinoethanol, N-methyl-3-pyrrolin-2-one, caprolactam, acetamide, caproamide, glutarimide, succinimide, 2-vinyl-pyrrolinone, diethylamide, and the like. Optionally, the impurities may also include at least one of pyridine, 2-methyl-1,3-dioxolane, cyclopentanone, amino formaldehyde, diethylene glycol, triethylene glycol, and the like.
In the above technical solution, in step S1, the auxiliary agent is at least one selected from oxalyl chloride, malonyl chloride, and succinyl chloride.
In the above technical scheme, in step S1, the mass ratio of the crude ethylene glycol raw material to the auxiliary agent is 1000: (0.9-5.3).
In the above technical scheme, in step S1, the reaction conditions are as follows: the temperature is 48-105 ℃, the pressure is 0.47-1.05 MPa, and the reaction time is 0.19-0.53 h.
In the above technical scheme, in the step S2, the rectification separation includes light component removal separation and heavy component removal separation. The rectifying tower adopted by the light component removing separation is a light component removing tower, and the number of theoretical plates is 5-12. And light components such as water, aldehyde and the like are produced at the top of the light component removal tower, and ethylene glycol and the like are fed into the tower kettle and are used as the feed of the heavy component removal tower. The heavy component removal separation adopts a rectifying tower as a heavy component removal tower, and the number of theoretical plates is 10-25. Qualified ethylene glycol products are collected from the top or the side line of the de-heavy tower, and heavy components such as diethylene glycol, triethylene glycol and the like are collected from the bottom of the tower.
In the technical scheme, the light component removal and separation operation conditions are as follows: the pressure is 9-33 kPa in absolute pressure, the temperature of the tower kettle is 120-177 ℃, the temperature of the tower top is 41-76 ℃, and the mass reflux ratio is 0.4-1.6.
In the technical scheme, the operation conditions of the de-weighting separation are as follows: the pressure is 9-32 kPa in absolute pressure, the temperature of the tower kettle is 274-353 ℃, the temperature of the tower top is 125-168 ℃, and the mass reflux ratio is 0.9-3.2.
The invention provides a separation system for recovering ethylene glycol in a polyester production process, which comprises a rectification system, wherein a raw material pre-reaction system is arranged in front of the rectification system, and the rectification system comprises a light component removal tower and a heavy component removal tower.
In the technical scheme, the raw material pre-reaction system comprises a crude ethylene glycol raw material heat exchanger and a reactor. The crude glycol raw material heat exchanger exchanges heat for low-pressure steam. The reactor may be filled with an inert packing, such as an inert bulk packing or an inert structured packing.
High molecular polymers such as polyesters and polyamides or oligomers thereof are generally stable at normal temperature, but complex side reactions such as etherification, cyclization, thermal degradation, thermal oxidative degradation and the like can occur at higher temperature, so that acetaldehyde, 2-methyl-1,3-dioxolane, N-ethylmorpholine, morpholine ethanol, pyridine, cyclopentanone, amino formaldehyde, glutarimide, succinimide, N-methyl-3-pyrroline-2-one, 2-vinyl-pyrroline, caprolactam, acetamide, diethylamide, hexanamide and other dozens of impurity components can be generated. The mixture system of the series of impurities and glycol is not only complicated, but also the mutual influence between glycol and various impurities cannot be clarified at present, for example, the inventor finds out in the practical research process: although the difference between the bubble points of part of impurities and ethylene glycol is large, the part of the impurities and the ethylene glycol present non-ideal gas-liquid equilibrium behavior due to the interaction effect of different chemical components, namely, the part of the impurities and the ethylene glycol are distilled out from the top of the rectifying tower at the same time, so that the ethylene glycol product contains impurities which have obvious influence on the chromaticity index, and how to effectively remove the impurities which influence the chromaticity is not clear at present.
The inventor creatively pre-reacts a crude glycol raw material and an auxiliary agent to enable the auxiliary agent to react with certain impurities which are difficult to separate to form new impurities, so that the bubble point difference between the impurities to be separated and the glycol is obviously increased or the non-ideal gas-liquid equilibrium behavior is destroyed, and further the effective separation of the glycol and the new impurities formed after the pretreatment is realized. The invention solves the technical problems that impurities in the crude glycol raw material are difficult to effectively separate and the purity and the quality of the glycol are influenced in the prior art, and has simple and effective process flow and easy industrial implementation.
Drawings
FIG. 1 is a schematic diagram of a separation system for ethylene glycol recovery in a polyester production process according to the present invention;
wherein the reference numerals are as follows:
1 is a crude glycol raw material storage tank, 2 is a crude glycol raw material heat exchanger, 3 is a reactor, 4 is a rectification feeding buffer tank, 5 is a light component removal tower, and 6 is a heavy component removal tower.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the present invention, the analysis of ethylene glycol components and the measurement of platinum-cobalt chromaticity were carried out according to the analysis methods of "measurement of 4.2 ethylene glycol content" and "measurement of 4.3 chromaticity" in the standard documents of "GB/T4649-2008 Industrial ethylene glycol".
In the invention, the content of nitrogen element in the ethylene glycol material is tested by adopting a Mitsubishi total nitrogen analyzer NSX-2100V analyzer, and the analysis method comprises the steps of argon flow rate of 200ml/min, oxygen flow rate of 400ml/min and combustion temperature of 1000-1050 ℃. The total nitrogen cumulative removal rate adopts a direct calculation method, and the calculation formula is as follows by mass:
the invention relates to a separation system for recovering ethylene glycol in a polyester production process (as shown in figure 1), which comprises: the rectification system is provided with a raw material pre-reaction system in front of the rectification system, and comprises a light component removal tower 5 and a heavy component removal tower 6. The raw material pre-reaction system comprises a crude glycol raw material heat exchanger 2 and a reactor 3. The crude glycol raw material heat exchanger exchanges heat with low-pressure steam. The reactor is filled with inert packing. The separation process is as follows: crude glycol raw materials (such as crude glycol is from a material which is extracted by a polyester vacuum system and is rich in glycol or a material which is primarily purified by a polyester process tower and is rich in glycol) enter a crude glycol raw material storage tank 1, the crude glycol raw materials and an auxiliary agent are mixed according to a certain proportion, the mixture is subjected to heat exchange by a crude glycol raw material heat exchanger 2 and then enters a reactor 3 for reaction, the obtained pretreated mixed material enters a rectifying and feeding buffer tank 4, then a lightness-removing tower 5 is subjected to lightness-removing treatment, and a glycol-containing material flow with light components removed enters a weight-removing tower 6 for weight-removing treatment to obtain a glycol product.
[ example 1 ]
The polyester used in this example is a copolymer of terephthalic acid, ethylene glycol and caprolactam, and the crude ethylene glycol drawn off by a polyester vacuum system consists of the following components by mass: ethylene glycol 82.3%, water 8.3%, acetaldehyde 0.4%, N-ethylmorpholine 0.12%, morpholine ethanol 0.14%, N-methyl-3-pyrrolin-2-one 0.33%, caprolactam 3.3%, acetamide 0.53%, caproamide 0.15%, glutarimide 0.11%, succinimide 0.46%, 2-vinyl-pyrrolinone 0.2%, diethylamide 0.23%, 2-methyl-1,3-dioxolane 0.26%, cyclopentanone 0.53%, amino formaldehyde 0.16%, diethylene glycol 0.75%, triethylene glycol 0.23%, and other components 1.50%. The mass content of nitrogen-containing impurities in the crude ethylene glycol was 9000ppm based on the total nitrogen.
The separation system used in this example (see fig. 1) was a low pressure steam heat exchanger in which the crude ethylene glycol feed exchanger was packed with inert structured packing. The auxiliary agent is malonyl chloride, and the mixture ratio of the crude glycol raw material to the auxiliary agent is, by mass, 1000:2.5. the operating conditions of the reactor were as follows: the temperature was 75 ℃, the operating pressure was 0.7MPa, and the reaction time was 0.35 hours.
The rectification system comprises two rectification towers, namely a light component removal tower and a heavy component removal tower. The number of theoretical plates of the light component removal tower is 8, and light components such as water, aldehyde and the like are produced at the top of the light component removal tower; the theoretical plate number of the de-heavy tower is 17, qualified ethylene glycol products are extracted from the top of the de-heavy tower, and heavy components such as diethylene glycol, triethylene glycol and the like are taken from the bottom of the tower. The operating conditions of the light component removal tower are as follows: the pressure is 20kPa in absolute pressure, the temperature of the tower bottom is 150 ℃, the temperature of the tower top is 60 ℃, and the mass reflux ratio is 1. The operating conditions of the de-heaving column were as follows: the pressure was 20kPa in absolute terms, the column bottom temperature was 313 ℃, the column top temperature was 150 ℃ and the mass reflux ratio was 2.
According to the analysis of the 4.2 ethylene glycol content determination in the standard document of GB/T4649-2008 Industrial ethylene glycol, the cumulative removal rate of the degradation impurities (calculated by total nitrogen) by the pre-reaction-rectification coupling process is 85%, and the mass purity of the ethylene glycol is 99.8%. The platinum-cobalt thermal chroma of the crude glycol is more than 500Hazen, and after separation, the platinum-cobalt thermal chroma of the obtained glycol product is reduced to 180Hazen.
[ example 2 ]
The composition of the crude ethylene glycol feed, the separation process steps and the apparatus used in this example to recover ethylene glycol during the production of polyesteramides were the same as in example 1. The difference from the embodiment 1 is only that partial parameters of the pre-reaction and rectification process are adjusted, and the specific points are as follows:
the crude glycol pre-reaction auxiliary agent is malonyl chloride, and the ratio of the crude glycol to the auxiliary agent is, by mass, 1000:5. the reaction conditions were as follows: the operating temperature is 100 ℃, the operating pressure is 1MPa, and the reaction time is 0.5 hour.
The rectification system comprises two rectification towers, namely a light component removal tower and a heavy component removal tower. The number of theoretical plates of the light component removal tower is 11, and light components such as water, aldehyde and the like are produced at the top of the light component removal tower; the theoretical plate number of the de-heavy tower is 24, qualified ethylene glycol products are extracted from the top of the de-heavy tower, and heavy components such as diethylene glycol, triethylene glycol and the like are taken from the bottom of the tower. The operating pressure of the light component removal tower is 10kPa in absolute pressure, the temperature of the tower bottom is 133 ℃, the temperature of the tower top is 46 ℃, and the mass reflux ratio is 1.5. The operating pressure of the de-heavy tower is 10kPa in absolute pressure, the temperature of the tower kettle is 288 ℃, the temperature of the tower top is 132 ℃, and the mass reflux ratio is 3.
According to the analysis of the 4.2 ethylene glycol content determination in the standard document of GB/T4649-2008 Industrial ethylene glycol, the cumulative removal rate of the degradation impurities (calculated by total nitrogen) by the pre-reaction-rectification coupling process is 92%, and the mass purity of the ethylene glycol is 99.9%. The platinum-cobalt thermal chroma of the crude glycol is more than 500Hazen, and after separation, the platinum-cobalt thermal chroma of the obtained glycol product is reduced to 95Hazen.
[ example 3 ] A method for producing a polycarbonate
The composition of the crude ethylene glycol feed, the separation process steps and the apparatus used in this example to recover ethylene glycol during the production of polyesteramides were the same as in example 1. The difference from the embodiment 1 is only that partial parameters of the pre-reaction and rectification process are adjusted, and the specific points are as follows:
the crude glycol pre-reaction auxiliary agent is malonyl chloride, and the ratio of the crude glycol to the auxiliary agent is, by mass, 1000:1. the reaction conditions were as follows: the operating temperature was 50 ℃, the operating pressure was 0.5MPa, and the reaction time was 0.2 hours.
The rectification system comprises two rectification towers, namely a light component removal tower and a heavy component removal tower. The number of theoretical plates of the light component removal tower is 6, and light components such as water, aldehyde and the like are produced at the top of the light component removal tower; the theoretical plate number of the de-heavy tower is 11, qualified ethylene glycol is extracted from the top of the de-heavy tower, and the tower kettle contains heavy components such as diethylene glycol, triethylene glycol and the like. The operating pressure of the light component removal tower is 30kPa in absolute pressure, the temperature of the tower bottom is 161 ℃, the temperature of the tower top is 69 ℃, and the mass reflux ratio is 0.5. The operating pressure of the heavy component removal tower is 30kPa in absolute pressure, the temperature of the tower bottom is 336 ℃, the temperature of the tower top is 160 ℃, and the mass reflux ratio is 1.
According to the analysis of the 4.2 ethylene glycol content determination in the standard document of GB/T4649-2008 Industrial ethylene glycol, the cumulative removal rate of the degradation impurities (calculated by total nitrogen) by the pre-reaction-rectification coupling process is 78%, and the mass purity of the ethylene glycol is 99.7%. The platinum-cobalt thermal chroma of the crude glycol is more than 500Hazen, and after separation, the platinum-cobalt thermal chroma of the obtained glycol product is reduced to 270Hazen.
[ example 4 ] A method for producing a polycarbonate
This example differs from example 3 only in that the crude ethylene glycol pre-reaction aid is oxalyl chloride, otherwise the same as example 3.
According to the analysis of the 4.2 ethylene glycol content determination in the standard document of GB/T4649-2008 Industrial ethylene glycol, the cumulative removal rate of the degradation impurities (calculated by total nitrogen) by the pre-reaction-rectification coupling process is 77%, and the mass purity of the ethylene glycol is 99.7%. The platinum-cobalt thermal chroma of the crude glycol is more than 500Hazen, and after separation, the platinum-cobalt thermal chroma of the obtained glycol product is reduced to 300Hazen.
[ example 5 ] A method for producing a polycarbonate
This example differs from example 2 only in that the crude ethylene glycol pre-reaction aid is succinyl chloride, otherwise the example 2 is the same.
According to the analysis of 4.2 glycol content determination in the standard document of GB/T4649-2008 technical glycol, the cumulative removal rate of the degradation impurities (calculated by total nitrogen) by the pre-reaction-rectification coupling process is 93wt%, and the mass purity of the glycol is 99.9%. The platinum-cobalt thermal chroma of the crude glycol is more than 500Hazen, and after separation, the platinum-cobalt thermal chroma of the obtained glycol product is reduced to 80Hazen.
[ example 6 ]
This example is the same as example 3 except that the preliminary reaction temperature of the crude ethylene glycol was adjusted to 20 ℃.
According to the analysis of the 4.2 ethylene glycol content determination in the standard document of GB/T4649-2008 Industrial ethylene glycol, the cumulative removal rate of the degradation impurities (calculated by total nitrogen) by the pre-reaction-rectification coupling process is 65%, and the mass purity of the ethylene glycol is 99.5%. The platinum-cobalt thermal chroma of the crude glycol is more than 500Hazen, and after separation, the platinum-cobalt thermal chroma of the obtained glycol product is reduced to 360Hazen.
Comparative example 1
This comparative example differs from example 3 only in that the amount of the crude ethylene glycol pre-reaction auxiliary was adjusted to 0, and the other examples are the same as example 3.
According to the analysis of 4.2 glycol content determination in the GB/T4649-2008 industrial glycol standard document, the cumulative removal rate of the degradation impurities (calculated by total nitrogen) by the pre-reaction-rectification coupling process is 20%, and the mass purity of the glycol is 98.7%. The platinum-cobalt thermal chroma before and after the purification of the crude glycol is more than 500Hazen.
Comparative example 2
The procedure and apparatus for the recovery of crude ethylene glycol as a raw material in the production of polyesteramide used in this comparative example were the same as those used in example 3. The difference between the comparative example and the example 3 is only that partial parameters of the rectification process are adjusted, and the specific points are as follows: the operating pressure of the light component removal tower is 80kPa in absolute pressure, the temperature of the tower bottom is 190 ℃, and the temperature of the tower top is 94 ℃. The operating pressure of the de-weighting tower is 80kPa in absolute pressure, the temperature of the tower kettle is 371 ℃, and the temperature of the tower top is 190 ℃.
According to the analysis of the 4.2 ethylene glycol content determination in the standard document of GB/T4649-2008 Industrial ethylene glycol, the accumulative removal rate of the degradation impurities (calculated by total nitrogen) by the pre-reaction-rectification coupling process is 40%, and the mass purity of the ethylene glycol is 99.1%. The platinum-cobalt thermal chroma before and after the purification of the crude glycol is more than 500Hazen.
The specific embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.
Claims (11)
1. A separation method for recovering ethylene glycol in a polyester production process, comprising:
s1, reacting a crude ethylene glycol raw material with an acyl chloride auxiliary agent to obtain a pretreated mixed material;
s2, rectifying and separating the pretreated mixed material to obtain a light component, an ethylene glycol product and a heavy component.
2. A process according to claim 1, wherein the polyester is polyethylene terephthalate or a copolymer of polyethylene terephthalate and a polyamide or a copolymer of terephthalic acid, ethylene glycol and caprolactam, preferably a copolymer of polyethylene terephthalate and a polyamide or a copolymer of terephthalic acid, ethylene glycol and caprolactam.
3. The method according to claim 1, wherein in step S1, the crude ethylene glycol raw material is a raw material containing crude ethylene glycol; the crude glycol is derived from a byproduct rich in glycol in the polyester production process; the crude ethylene glycol comprises ethylene glycol and impurities, wherein the impurities comprise chain or annular aldehyde, chain or annular ketone and chain or annular nitrogen-containing impurities.
4. The method according to claim 1 or 3, wherein in step S1, the mass content of the ethylene glycol in the crude ethylene glycol raw material is 75-95%; the platinum-cobalt thermochromism of the crude ethylene glycol is more than 500Hazen;
preferably, the impurity is contained in an amount of not less than 5ppm, preferably not less than 50ppm, more preferably not less than 100ppm by mass based on the total nitrogen element.
5. The method of claim 3, wherein the impurities comprise water, acetaldehyde, N-ethylmorpholine, morpholine ethanol, N-methyl-3-pyrroline-2-one, caprolactam, acetamide, hexanamide, glutarimide, succinimide, 2-vinyl-pyrrolinone, diethylamide;
optionally, the impurities further comprise at least one of pyridine, 2-methyl-1,3-dioxolane, cyclopentanone, amino formaldehyde, diethylene glycol, triethylene glycol.
6. The method according to claim 1, wherein in step S1, the auxiliary agent is at least one selected from the group consisting of oxalyl chloride, malonyl chloride, and succinyl chloride.
7. The method according to claim 1, wherein in step S1, the mass ratio of the crude ethylene glycol raw material to the auxiliary agent is 1000: (0.9 to 5.3);
and/or, in step S1, the reaction conditions are as follows: the temperature is 48-105 ℃, the pressure is 0.47-1.05 MPa, and the reaction time is 0.19-0.53 h.
8. The method according to claim 1, wherein in step S2, the rectification separation comprises light component removal separation and heavy component removal separation; wherein the rectifying tower adopted by the light component removal separation is a light component removal tower, the number of theoretical plates is 5-12, light components are extracted from the top of the light component removal tower, and the material flow containing glycol is taken as the feed of a heavy component removal tower at the bottom of the tower; the heavy component removal separation adopts a rectifying tower as a heavy component removal tower, and the number of theoretical plates is 10-25; ethylene glycol products are extracted from the top or side line of the heavy component removal tower, and heavy components are extracted from the bottom of the tower.
9. The process according to claim 8, characterized in that the operating conditions of the light ends separation are as follows: the pressure is 9-33 kPa in absolute pressure, the temperature of the tower kettle is 120-177 ℃, the temperature of the tower top is 41-76 ℃, and the mass reflux ratio is 0.4-1.6;
and/or the operation conditions of the de-heavy separation are as follows: the pressure is 9-32 kPa in absolute pressure, the temperature of the tower kettle is 274-353 ℃, the temperature of the tower top is 125-168 ℃, and the mass reflux ratio is 0.9-3.2.
10. A separation system for recovering ethylene glycol in the polyester production process comprises a rectification system, wherein a raw material pre-reaction system is arranged in front of the rectification system, and the rectification system comprises a light component removal tower and a heavy component removal tower.
11. The system of claim 10, wherein the feed pre-reaction system comprises a crude ethylene glycol feed heat exchanger, a reactor;
preferably, the crude glycol raw material heat exchanger is used for low-pressure steam heat exchange;
preferably, the reactor is packed with inert packing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110495507.9A CN115304454A (en) | 2021-05-07 | 2021-05-07 | Separation method and system for recovering ethylene glycol in polyester production process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110495507.9A CN115304454A (en) | 2021-05-07 | 2021-05-07 | Separation method and system for recovering ethylene glycol in polyester production process |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115304454A true CN115304454A (en) | 2022-11-08 |
Family
ID=83853628
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110495507.9A Pending CN115304454A (en) | 2021-05-07 | 2021-05-07 | Separation method and system for recovering ethylene glycol in polyester production process |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115304454A (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003342209A (en) * | 2002-05-23 | 2003-12-03 | Mitsubishi Chemicals Corp | Method for producing dimethyl carbonate and ethylene glycol |
| US20080045728A1 (en) * | 2004-07-21 | 2008-02-21 | Kruper William J Jr | Conversion of a Multihydroxylated-Aliphatic Hydrocarbon or Ester Thereof to a Chlorohydrin |
| CN101928201A (en) * | 2009-06-26 | 2010-12-29 | 上海焦化有限公司 | Purification technique for coal glycol rude products |
| CN105541551A (en) * | 2016-02-04 | 2016-05-04 | 天津大学 | Reaction-rectification-separation-refinement novel method, technique and device of ethylene glycol and 1,2-butanediol |
| CN105622343A (en) * | 2016-02-04 | 2016-06-01 | 天津大学 | Novel device and process for reactive distillation type separation of liquid-phase products obtained in ethylene glycol preparation based on biomass |
| WO2017133357A1 (en) * | 2016-02-04 | 2017-08-10 | 天津大学 | Method, process, and apparatus for separating ethylene glycol and 1,2-butylene glycol |
| CN108794300A (en) * | 2018-05-18 | 2018-11-13 | 岳阳昌德化工实业有限公司 | The Isolation method of raw material containing ethylene glycol and 1,2- butanediols and the preparation method of epoxy butane |
| US20210087130A1 (en) * | 2019-09-25 | 2021-03-25 | Nan Ya Plastics Corporation | Method for purifying by-product ethylene glycol of polyester in converting plasticizer |
-
2021
- 2021-05-07 CN CN202110495507.9A patent/CN115304454A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003342209A (en) * | 2002-05-23 | 2003-12-03 | Mitsubishi Chemicals Corp | Method for producing dimethyl carbonate and ethylene glycol |
| US20080045728A1 (en) * | 2004-07-21 | 2008-02-21 | Kruper William J Jr | Conversion of a Multihydroxylated-Aliphatic Hydrocarbon or Ester Thereof to a Chlorohydrin |
| CN101928201A (en) * | 2009-06-26 | 2010-12-29 | 上海焦化有限公司 | Purification technique for coal glycol rude products |
| CN105541551A (en) * | 2016-02-04 | 2016-05-04 | 天津大学 | Reaction-rectification-separation-refinement novel method, technique and device of ethylene glycol and 1,2-butanediol |
| CN105622343A (en) * | 2016-02-04 | 2016-06-01 | 天津大学 | Novel device and process for reactive distillation type separation of liquid-phase products obtained in ethylene glycol preparation based on biomass |
| WO2017133357A1 (en) * | 2016-02-04 | 2017-08-10 | 天津大学 | Method, process, and apparatus for separating ethylene glycol and 1,2-butylene glycol |
| CN108794300A (en) * | 2018-05-18 | 2018-11-13 | 岳阳昌德化工实业有限公司 | The Isolation method of raw material containing ethylene glycol and 1,2- butanediols and the preparation method of epoxy butane |
| US20210087130A1 (en) * | 2019-09-25 | 2021-03-25 | Nan Ya Plastics Corporation | Method for purifying by-product ethylene glycol of polyester in converting plasticizer |
Non-Patent Citations (2)
| Title |
|---|
| ZIJIE WANG ET AL.: "Universal Janus Filters for the Rapid Separation of Oil from Emulsions Stabilized by Ionic or Nonionic Surfactants", 《ANGEW. CHEM. INT. ED.》, vol. 56, 7 September 2017 (2017-09-07), pages 12892 - 12897, XP072087864, DOI: 10.1002/anie.201706158 * |
| 张陆军 等: "乙二醇再生与回收的再生工艺参数优化", 《云南化工》, vol. 47, no. 7, 31 July 2020 (2020-07-31), pages 114 - 116 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR100388119B1 (en) | Acrylic acid recovery method | |
| CN101389591B (en) | Process for the preparation of an alkanediol and a dialkyl carbonate | |
| CN100558694C (en) | The Azotropic distillation method of separating acetic acid, methyl acetate and water in the preparation aromatic carboxylic acid process | |
| US8231765B2 (en) | Process for the purification of lactams | |
| CN110372512B (en) | Separation and purification process of dimethyl carbonate | |
| US4199410A (en) | Purification of crude acrylic acid | |
| CN109608363B (en) | Method for purifying adiponitrile | |
| CN115073415A (en) | Method for preparing high-purity glycolide | |
| KR100551461B1 (en) | Process for working up crude, liquid vinyl acetate | |
| CN115304454A (en) | Separation method and system for recovering ethylene glycol in polyester production process | |
| JPS6261006B2 (en) | ||
| CN113754539B (en) | Purification and decolorization method of dimethyl oxalate | |
| CN1088060C (en) | Process to prepare 'epsilon'-caprolactam from 6-aminocaproic acid | |
| JP2506021B2 (en) | Purification method of caprolactam | |
| CN1162952A (en) | Process for the removal of color forming material from 1,x butanediol and its application to the preparation of ptmeg | |
| CN115304455A (en) | Purification method and system for recovering ethylene glycol in polyester production process | |
| US6494996B2 (en) | Process for removing water from aqueous methanol | |
| KR100584677B1 (en) | A high-efficient method for preparing acrylic acid | |
| JPH03181440A (en) | Purification of acrylic acid by distillation | |
| CN115181011B (en) | Preparation process of high-purity phenoxyethanol | |
| JP3866876B2 (en) | Method for recovering dimethyl terephthalate | |
| CN220513452U (en) | Piperidine separation and purification system | |
| CN114163330B (en) | Refining method of dimethyl carbonate crude product | |
| CN114539018B (en) | Preparation process of electronic grade propylene | |
| JPS61289069A (en) | Production of highly pure n-vinylformamide |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |