CN116239446A - Separation and recovery process of byproduct mixed alcohol of polyester device - Google Patents
Separation and recovery process of byproduct mixed alcohol of polyester device Download PDFInfo
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- CN116239446A CN116239446A CN202211658169.7A CN202211658169A CN116239446A CN 116239446 A CN116239446 A CN 116239446A CN 202211658169 A CN202211658169 A CN 202211658169A CN 116239446 A CN116239446 A CN 116239446A
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- diethylene glycol
- ethylene glycol
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- 238000000926 separation method Methods 0.000 title claims abstract description 48
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 title claims abstract description 45
- 238000011084 recovery Methods 0.000 title claims abstract description 35
- 229920000728 polyester Polymers 0.000 title claims abstract description 34
- 239000006227 byproduct Substances 0.000 title claims abstract description 27
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims abstract description 302
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 claims abstract description 273
- 238000007670 refining Methods 0.000 claims abstract description 84
- 238000001704 evaporation Methods 0.000 claims abstract description 47
- 230000008020 evaporation Effects 0.000 claims abstract description 42
- 239000000047 product Substances 0.000 claims abstract description 35
- 239000000203 mixture Substances 0.000 claims abstract description 16
- 239000000284 extract Substances 0.000 claims abstract description 12
- 238000010992 reflux Methods 0.000 claims description 36
- 238000009835 boiling Methods 0.000 claims description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 20
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 claims description 14
- 238000012856 packing Methods 0.000 claims description 12
- 238000010924 continuous production Methods 0.000 claims description 2
- 230000010485 coping Effects 0.000 abstract description 2
- 238000000605 extraction Methods 0.000 description 10
- 238000000034 method Methods 0.000 description 10
- 239000000178 monomer Substances 0.000 description 7
- 239000000945 filler Substances 0.000 description 6
- 239000007788 liquid Substances 0.000 description 6
- 238000006116 polymerization reaction Methods 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- CYJRNFFLTBEQSQ-UHFFFAOYSA-N 8-(3-methyl-1-benzothiophen-5-yl)-N-(4-methylsulfonylpyridin-3-yl)quinoxalin-6-amine Chemical compound CS(=O)(=O)C1=C(C=NC=C1)NC=1C=C2N=CC=NC2=C(C=1)C=1C=CC2=C(C(=CS2)C)C=1 CYJRNFFLTBEQSQ-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229920005862 polyol Polymers 0.000 description 4
- 150000003077 polyols Chemical class 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000006068 polycondensation reaction Methods 0.000 description 3
- -1 polyethylene terephthalate Polymers 0.000 description 3
- 238000000746 purification Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- IKHGUXGNUITLKF-UHFFFAOYSA-N Acetaldehyde Chemical compound CC=O IKHGUXGNUITLKF-UHFFFAOYSA-N 0.000 description 2
- 239000004229 Alkannin Substances 0.000 description 2
- 239000004230 Fast Yellow AB Substances 0.000 description 2
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 2
- 239000004231 Riboflavin-5-Sodium Phosphate Substances 0.000 description 2
- 239000004234 Yellow 2G Substances 0.000 description 2
- 150000001298 alcohols Chemical class 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000003245 coal Substances 0.000 description 2
- 239000000571 coke Substances 0.000 description 2
- 238000004821 distillation Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 125000003827 glycol group Chemical group 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229920000139 polyethylene terephthalate Polymers 0.000 description 2
- 239000005020 polyethylene terephthalate Substances 0.000 description 2
- 239000004172 quinoline yellow Substances 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 239000002151 riboflavin Substances 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 239000004149 tartrazine Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 1
- BMRWNKZVCUKKSR-UHFFFAOYSA-N butane-1,2-diol Chemical compound CCC(O)CO BMRWNKZVCUKKSR-UHFFFAOYSA-N 0.000 description 1
- 238000003889 chemical engineering Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000032050 esterification Effects 0.000 description 1
- 238000005886 esterification reaction Methods 0.000 description 1
- 239000011552 falling film Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 229960004063 propylene glycol Drugs 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
-
- 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
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/01—Preparation of ethers
- C07C41/34—Separation; Purification; Stabilisation; Use of additives
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/01—Preparation of ethers
- C07C41/34—Separation; Purification; Stabilisation; Use of additives
- C07C41/40—Separation; Purification; Stabilisation; Use of additives by change of physical state, e.g. by crystallisation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/01—Preparation of ethers
- C07C41/34—Separation; Purification; Stabilisation; Use of additives
- C07C41/40—Separation; Purification; Stabilisation; Use of additives by change of physical state, e.g. by crystallisation
- C07C41/42—Separation; Purification; Stabilisation; Use of additives by change of physical state, e.g. by crystallisation by distillation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/62—Plastics recycling; Rubber recycling
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Crystallography & Structural Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a separation and recovery process of byproduct mixed alcohol of a polyester device, which comprises the following steps: (1) The mixed alcohol from the byproduct of the polyester device enters a light component removing tower, a first light component is extracted from the tower top, and a first heavy component in the tower bottom enters an evaporation tower; (2) The tower bottom of the evaporation tower extracts a second heavy component, and the tower top extracts a second light component to enter an ethylene glycol refining tower; (3) The side line of the ethylene glycol refining tower extracts an ethylene glycol product, the top of the tower extracts a third light component, and a third heavy component in the tower bottom enters the diethylene glycol refining tower; (4) The side line of the diethylene glycol refining tower is used for extracting a diethylene glycol product, the top of the diethylene glycol refining tower is used for extracting a fourth light component, and the bottom of the diethylene glycol refining tower is used for extracting a fourth heavy component; the separation and recovery process optimizes the existing separation process according to the characteristics of the byproduct mixed alcohol mixture of the polyester device, and the improved separation and recovery process has the advantages of being capable of flexibly coping with the change of the feed composition, can improve the product quality and recovery rate, and has a good application prospect.
Description
Technical Field
The invention belongs to the technical field of chemical engineering, and particularly relates to a separation and recovery process of byproduct mixed alcohol of a polyester device.
Background
Conventional polyesters, commonly referred to as polyethylene terephthalate (PET), are obtained from terephthalic acid (PTA) and Ethylene Glycol (EG) by esterification and polycondensation. In recent years, with the continuous expansion of polyester productivity, the market product has serious homogeneity, and the pursuit of differentiated competition of products becomes an important direction of industry development. The differential polyester is usually modified by introducing a third monomer or a fourth monomer based on the conventional polyester to synthesize different functional polyesters. In order to prepare high molecular weight polyesters, high vacuum is usually used to remove small molecular monomers during polycondensation and final polymerization, during which process excess unreacted monomers are pumped into a steam jet pump and condensed for reuse, and if the introduced third monomer is a glycol (e.g., diethylene glycol), the unreacted mixed alcohol is purified and separated before being recycled.
The ethylene glycol and diethylene glycol (also known as diethylene glycol) in the mixed alcohol are typically separated using a rectification apparatus. In the polyester polymerization process, a high vacuum process is adopted in the polycondensation and final polymerization working section, the extracted unreacted mixed alcohol contains substances such as moisture, light components, oligomers and the like, and when the ethylene glycol in the materials occupies relatively high proportion, the oligomers are dissolved in the ethylene glycol and cannot influence the rectification process. Ethylene glycol belongs to heat-sensitive substances, and is easy to condense and coke at high temperature, so that stable operation of the device and quality of products are affected, and therefore, vacuum operation is often adopted for rectification and separation of ethylene glycol, and the operation temperature of a tower kettle is reduced. Due to the low operating temperature of the rectifying tower, along with the continuous extraction of ethylene glycol, the oligomer dissolved in the ethylene glycol can separate out a blocking filler or a tower plate, thereby influencing the rectifying and separating effect. The polymerization reaction has more byproducts, the change of the feed composition of the mixed alcohol has great influence on the rectifying separation effect, for example, the byproducts have intermediate components with boiling points between water and glycol, and the intermediate components with boiling points between glycol and diglycol, and the glycol and diglycol are separated according to the boiling point by adopting the conventional method, so that the number of towers is large, the flow is complex, and the operation difficulty is high; if the separation towers are arranged in sequence according to the boiling point of water, glycol, diglycol and oligomers, the purity of the product is difficult to be ensured to be more than 99 percent.
CN109179542a provides a distillation system and distillation process for ethylene glycol and diethylene glycol in a polyol waste liquid, the polyol waste liquid is uniformly treated after collection, the composition is stable, and the melting point of an oligomer in a polyol device is lower than that of the oligomer in a polyester device, and a filler or a tower plate is not easy to block, so that the treatment process is not suitable for mixed alcohol separation of the polyester device.
CN105085165a provides a separation method of ethylene glycol and diethylene glycol, wherein the feed composition is a crude ethylene glycol stream in the process of producing ethylene glycol from coal-based synthesis gas, methanol, ethanol, water, 1,2 propylene glycol, 1,2 butylene glycol and other byproducts are removed before the crude ethylene glycol stream enters an ethylene glycol and diethylene glycol separation system, the feed composition is stable, oligomers are not contained, the diethylene glycol content produced in the process of producing ethylene glycol from coal-based synthesis gas is far lower than the diethylene glycol content in byproduct alcohol of a polyester device, and stable product quality is difficult to obtain by using the method to treat the mixed alcohol of the polyester device.
In summary, how to refer to the existing technology of separating and recovering the polyol to realize the efficient separation of the byproduct mixed alcohol of the polyester device is a technical problem to be solved currently.
Disclosure of Invention
Aiming at the problems existing in the prior art, the invention aims to provide a separation and recovery process of byproduct mixed alcohol of a polyester device, which optimizes the existing separation process according to the characteristics of the byproduct mixed alcohol mixture of the polyester device, and the improved separation and recovery process has the advantage of flexibly coping with the change of the feed composition, can improve the quality and recovery rate of products, and has good application prospect.
To achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the invention provides a separation and recovery process of byproduct mixed alcohol of a polyester device, which comprises the following steps:
(1) The mixed alcohol from the byproduct of the polyester device enters a light component removing tower, a first light component is extracted from the tower top, and a first heavy component in the tower bottom enters an evaporation tower;
(2) The tower bottom of the evaporation tower extracts a second heavy component, and the tower top extracts a second light component to enter an ethylene glycol refining tower;
(3) According to the composition of the second light component in the step (2), the side line of the ethylene glycol refining tower is used for extracting an ethylene glycol product, the top of the tower is used for extracting a third light component, and the third heavy component in the tower bottom enters the diethylene glycol refining tower;
or the tower top of the ethylene glycol refining tower extracts an ethylene glycol product, and the third heavy component in the tower bottom enters the diethylene glycol refining tower;
(4) And the side line of the diethylene glycol refining tower is used for extracting a diethylene glycol product, the top of the diethylene glycol refining tower is used for extracting a fourth light component, and the bottom of the diethylene glycol refining tower is used for extracting a fourth heavy component.
The following technical scheme is a preferred technical scheme of the invention, but is not a limitation of the technical scheme provided by the invention, and the technical purpose and beneficial effects of the invention can be better achieved and realized through the following technical scheme.
As a preferred embodiment of the present invention, the mixed alcohol in the step (1) includes water, ethylene glycol, diethylene glycol and an oligomer.
Preferably, the mixed alcohol in the step (1) comprises 1 to 10wt% of water, for example 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, etc.; 70 to 95wt% of ethylene glycol, for example, 70wt%, 75wt%, 80wt%, 85wt%, 90wt% or 95wt%, etc.; diethylene glycol 5 to 20wt%, for example 5wt%, 10wt%, 15wt% or 20wt%, etc.; and 0.01 to 10wt% of an oligomer, for example, 0.01wt%, 0.05wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%, etc., the selection of the above values is not limited to the values recited, and other values not recited in the respective value ranges are equally applicable.
As a preferred embodiment of the present invention, the mixed alcohol of step (1) further comprises at least one of a first intermediate component, a second intermediate component or a third intermediate component, for example, a first intermediate component and a second intermediate component, a first intermediate component, a second intermediate component and a third intermediate component, a first intermediate component and a third intermediate component, and the like.
Preferably, the first intermediate component comprises a component having a boiling point lower than that of water, and a component having a boiling point between water and 110 ℃.
Preferably, the second intermediate component comprises a component having a boiling point between 110 ℃ and ethylene glycol.
Preferably, the third intermediate component comprises a component having a boiling point between ethylene glycol and diethylene glycol.
Preferably, the fourth intermediate component comprises a component having a boiling point between diethylene glycol and the oligomer.
Preferably, the first intermediate component is present in the mixed alcohol of step (1) in an amount of 0 to 5wt%, for example 0wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, etc.; the content of the second intermediate component is 0 to 5wt%, for example, 0wt%, 1wt%, 2wt%, 3wt%, 4wt% or 5wt%, etc.; the content of the third intermediate component is 0 to 5wt%, for example, 0wt%, 1wt%, 2wt%, 3wt%, 4wt% or 5wt%, etc.; the content of the fourth intermediate component is 0 to 5wt%, for example, 0wt%, 1wt%, 2wt%, 3wt%, 4wt%, or 5wt%, etc., and the selection of the above values is not limited to the recited values, and other non-recited values are equally applicable within the respective value ranges.
In a preferred embodiment of the present invention, the theoretical plate number of the light ends removal column in the step (1) is 5 to 25, for example, 5, 10, 15, 20 or 25, etc., but the present invention is not limited to the recited values, and other non-recited values within the recited values are equally applicable.
Preferably, the overhead operating pressure of the light ends column in step (1) is from-0.01 MPaG to-0.09 MPaG, for example, -0.01MPaG, -0.02MPaG, -0.03MPaG, -0.04MPaG, -0.05MPaG, -0.06MPaG, -0.07MPaG, -0.08MPaG or-0.09 MPaG, etc., but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.
Preferably, the bottom operation temperature of the light component removal column in the step (1) is 110 to 180 ℃, for example 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃ or the like, but the present invention is not limited to the recited values, and other non-recited values within the range of the recited values are equally applicable.
Preferably, the reflux ratio of the light ends column in step (1) is 0.1 to 10, for example 0.1, 1,2, 4, 6, 8 or 10, etc., but is not limited to the recited values, and other non-recited values within this range are equally applicable.
Preferably, the first light component of step (1) comprises water and/or a first intermediate component.
In a preferred embodiment of the present invention, the top operating pressure of the evaporation column in the step (2) is from-0.04 MPaG to-0.099 MPaG, for example, -0.04MPaG, -0.05MPaG, -0.06MPaG, -0.07MPaG, -0.08MPaG or-0.099 MPaG, etc., but the present invention is not limited to the above-mentioned values, and other values not mentioned in the above-mentioned value range are applicable.
Preferably, the evaporator in step (2) is operated at a temperature of 110 to 200 ℃, for example 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃, etc., but is not limited to the values recited, and other values not recited in the range are equally applicable.
Preferably, the second heavy component of step (2) comprises an oligomer and/or a fourth intermediate component.
In a preferred embodiment of the present invention, the theoretical plate number of the ethylene glycol purification column in the step (3) is 10 to 40, for example, 10, 15, 20, 25, 30, 35 or 40, etc., but the theoretical plate number is not limited to the recited values, and other non-recited values within the recited value range are equally applicable.
Preferably, the top operating pressure of the ethylene glycol refining column in step (3) is from-0.04 MPaG to-0.099 MPaG, for example, -0.04MPaG, -0.05MPaG, -0.06MPaG, -0.07MPaG, -0.08MPaG, or-0.099 MPaG, etc., but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.
Preferably, the operation temperature of the bottom of the ethylene glycol purification column in the step (3) is 110 to 200 ℃, for example 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃, or the like, but the present invention is not limited to the above-mentioned values, and other values not mentioned in the above-mentioned value range are equally applicable.
Preferably, the reflux ratio of the ethylene glycol purification column in the step (3) is 0.1 to 10, for example, 0.1, 1,2, 4, 6, 8 or 10, etc., but is not limited to the recited values, and other non-recited values within the range are equally applicable.
As a preferable technical scheme of the invention, when the second intermediate component is not contained in the second light component in the step (3), optionally one of the following extraction schemes is adopted, namely, the ethylene glycol product is extracted from the side line of the ethylene glycol refining tower, the third light component is extracted from the tower top, and the third heavy component in the tower bottom enters the diethylene glycol refining tower; or the tower top of the ethylene glycol refining tower extracts the ethylene glycol product, and the third heavy component in the tower bottom enters the diethylene glycol refining tower.
Preferably, when the second light component in the step (3) contains the second intermediate component, the side line of the ethylene glycol refining tower is used for extracting an ethylene glycol product, the top of the tower is used for extracting a third light component, and the third heavy component in the tower bottom enters the diethylene glycol refining tower.
Preferably, the ethylene glycol product in step (3) is withdrawn from the side line of the theoretical plates 2-10 from top to bottom, such as theoretical plate 2, theoretical plate 3, theoretical plate 4, theoretical plate 5, theoretical plate 6, theoretical plate 7, theoretical plate 8, theoretical plate 9, theoretical plate 10, etc., but not limited to the recited values, and other non-recited values within the range of values are equally applicable.
Preferably, the third light component of step (3) comprises a second intermediate component.
In a preferred embodiment of the present invention, the theoretical plate number of the diethylene glycol purifying column in the step (4) is 5 to 30, for example, 5, 10, 15, 20, 25 or 30, etc., but the present invention is not limited to the above-mentioned values, and other values not mentioned in the above-mentioned value range are equally applicable.
Preferably, the diethylene glycol refining column of step (4) has a column top operating pressure of from-0.04 MPaG to-0.099 MPaG, such as-0.04 MPaG, -0.05MPaG, -0.06MPaG, -0.07MPaG, -0.08MPaG, or-0.099 MPaG, etc., but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.
Preferably, the operation temperature of the column bottom of the diethylene glycol refining column in the step (4) is 110 to 200 ℃, for example 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃ or the like, but not limited to the values listed, and other values not listed in the range of the values are equally applicable.
Preferably, the reflux ratio of the diethylene glycol refining column in step (4) is 0.1 to 10, for example, 0.1, 1,2, 4, 6, 8 or 10, etc., but is not limited to the recited values, and other non-recited values within the range are equally applicable.
Preferably, the diethylene glycol product of step (4) is withdrawn from the side line of the theoretical plates 3 to 10 from top to bottom, such as theoretical plate 3, theoretical plate 4, theoretical plate 5, theoretical plate 6, theoretical plate 7, theoretical plate 8, theoretical plate 9, theoretical plate 10, etc., but not limited to the recited values, and other non-recited values within this range are equally applicable.
Preferably, the fourth light component of step (4) comprises ethylene glycol and diethylene glycol.
In the step (4), the top extraction component of the diethylene glycol refining tower is a mixture of part of ethylene glycol and diethylene glycol (namely a fourth light component), and the purity of the diethylene glycol product can be ensured by adjusting the top extraction amount according to the composition change of the feed mixed alcohol in the step (1).
As a preferable technical scheme of the invention, the evaporation tower in the step (2) comprises any one of an evaporation tower without a reflux band wire mesh, an evaporation tower without a reflux band one section of packing, an evaporation tower with a reflux band one section of packing or an evaporation tower with a reflux band tower plate.
Preferably, in the evaporation tower without the reflux zone and the evaporation tower with the reflux zone, the height of the packing is independently 1-3 m, such as 1m, 1.5m, 2m, 2.5m or 3m, but not limited to the recited values, and other non-recited values in the range of the values are equally applicable.
Preferably, the theoretical plate number of the evaporation tower with the reflux band tower plate is 2-10, for example, 2, 4, 6, 8 or 10, etc., but is not limited to the listed values, and other non-listed values are applicable in the range of the values.
As a preferable technical scheme of the invention, the separation and recovery process of the byproduct mixed alcohol of the polyester device is a continuous process.
In the present invention, the light component removing column, the ethylene glycol refining column and the diethylene glycol refining column each independently include a reboiler.
Preferably, the reboiler comprises either or a combination of a forced circulation reboiler or a falling film reboiler.
As a preferable technical scheme of the invention, the fourth monomer introduced into the polyester device is glycol with the boiling point between that of ethylene glycol and diethylene glycol, and can be extracted from the top of the diethylene glycol refining tower in the step (4), and a new separation tower is introduced for separation, which belongs to the extension technology of the invention.
As a preferable technical scheme of the invention, the polyester device introduces a fourth monomer which is dihydric alcohol with boiling point higher than that of diethylene glycol, can be extracted from the tower bottom of the diethylene glycol refining tower in the step (4), and is introduced into a new separating tower for separation, and also belongs to the extension technology of the invention.
Compared with the prior art, the invention has the following beneficial effects:
(1) The separation and recovery process removes the oligomer before alcohol substances are separated, avoids the blockage of a later stage tower plate or filler, prolongs the service life of the device and saves the cost;
(2) The separation and recovery process provided by the invention is characterized in that aiming at the characteristics of more polymerization byproducts and larger influence of the change of the feed composition of the mixed alcohol on the rectifying and separating effect, various components are reasonably arranged, including components with boiling points lower than that of water, intermediate components with boiling points between 110 ℃ and ethylene glycol, the extraction position of the intermediate components with boiling points between ethylene glycol and diethylene glycol, and the extraction amount of each part can be regulated under the condition of not changing a tower to meet the purity and yield of ethylene glycol and diethylene glycol, so that the purity of ethylene glycol is more than 99.2wt%, the yield is more than 95.8%, the purity of diethylene glycol is more than 99.2wt%, and the yield is more than 86.8%.
Drawings
FIG. 1 is a flow chart of a process for separating and recovering mixed alcohol as a byproduct of a polyester apparatus according to an embodiment of the invention.
Wherein, C-101 is a light component removing tower, C-102 is an evaporating tower, C-103 is an ethylene glycol refining tower, C-104 is a diethylene glycol refining tower, E-101 is a light component removing tower condenser, E-102 is a light component removing tower reboiler, E-103 is an evaporating tower condenser, E-104 is an evaporating tower reboiler, E-105 is an ethylene glycol refining tower condenser, E-106 is an ethylene glycol refining tower reboiler, E-107 is a diethylene glycol refining tower condenser, E-108 is a diethylene glycol refining tower reboiler, P-101 is a light component removing tower reflux pump, P-102 is a light component removing tower kettle pump, P-103 is an evaporating tower kettle pump, P-104 is an ethylene glycol refining tower reflux pump, P-105 is an ethylene glycol product extracting pump, P-106 is an ethylene glycol refining tower kettle pump, P-107 is a diethylene glycol refining tower reflux pump, P-108 is a diethylene glycol product extracting pump, and P-109 is a diethylene glycol refining tower kettle pump.
Detailed Description
For better illustrating the present invention, the technical scheme of the present invention is convenient to understand, and the present invention is further described in detail below. The following examples are merely illustrative of the present invention and are not intended to represent or limit the scope of the invention as defined in the claims.
In one specific embodiment, the invention provides a separation and recovery device for byproduct mixed alcohol of a polyester device, which comprises a light component removal tower C-101, an evaporation tower C-102, an ethylene glycol refining tower C-103 and a diethylene glycol refining tower C-104 which are connected in sequence;
the light component removing tower C-101 comprises a light component removing tower condenser E-101, a light component removing tower reflux pump P-101, a light component removing tower reboiler E-102 and a light component removing tower bottom liquid pump P-102;
the evaporation tower C-102 comprises an evaporation tower condenser E-103, an evaporation tower reboiler E-104 and an evaporation tower kettle liquid pump P-103;
the evaporation tower C-102 comprises an evaporation tower without a reflux band wire mesh, an evaporation tower without a reflux band with a section of filler, an evaporation tower with a reflux band with a section of filler or an evaporation tower with a reflux band tower plate;
further, in the evaporation tower without the reflux and with the one-section packing and the evaporation tower with the reflux and the one-section packing, the heights of the packing are independently 1-3 m;
further, the theoretical plate number of the evaporation tower with the reflux belt tower plate is 2-10;
the ethylene glycol refining tower C-103 comprises an ethylene glycol refining tower condenser E-105, an ethylene glycol refining tower reflux pump P-104, an ethylene glycol refining tower reboiler E-106, an ethylene glycol product extraction pump P-105 and an ethylene glycol refining tower kettle liquid pump P-106;
the diethylene glycol refining tower C-104 comprises a diethylene glycol refining tower condenser E-107, a diethylene glycol refining tower reflux pump P-107, a diethylene glycol refining tower reboiler E-108, a diethylene glycol product extraction pump P-108 and a diethylene glycol refining tower bottom liquid pump P-109.
The invention also provides a separation and recovery process of the byproduct mixed alcohol of the polyester device, which is carried out based on the separation and recovery device in the specific embodiment, and the separation and recovery process is shown in figure 1 and comprises the following steps:
(1) The mixed alcohol from the byproduct of the polyester device enters a light component removing tower C-101, a first light component is extracted from the tower top, and a first heavy component in the tower bottom enters an evaporating tower C-102;
wherein the mixed alcohol comprises, by mass, 1-10wt% of water, 70-95wt% of ethylene glycol, 5-20wt% of diethylene glycol and 0.01-10wt% of oligomer; the composition also comprises 0 to 5 weight percent of first intermediate component, 0 to 5 weight percent of second intermediate component, 0 to 5 weight percent of third intermediate component and 0 to 5 weight percent of fourth intermediate component;
further, the first intermediate component comprises a component having a boiling point lower than that of water, and a component having a boiling point between water and 110 ℃; the second intermediate component comprises a component having a boiling point between 110 ℃ and ethylene glycol; the third intermediate component comprises a component having a boiling point between ethylene glycol and diethylene glycol; the fourth intermediate component comprises a component having a boiling point between diethylene glycol and an oligomer;
further, the theoretical plate number of the light component removal column C-101 is 5-25, the column top operation pressure is-0.01 MPaG to-0.09 MPaG, the column bottom operation temperature is 110-180 ℃, and the reflux ratio is 0.1-10;
further, the first light component comprises water and/or a first intermediate component;
(2) The tower bottom of the evaporation tower C-102 is used for extracting a second heavy component (comprising an oligomer and/or a fourth intermediate component), and the tower top is used for extracting a second light component to enter the glycol refining tower C-103;
wherein the top operation pressure of the evaporation tower C-102 is-0.04 MPaG to-0.099 MPaG, and the tower kettle operation temperature is 110-200 ℃;
(3) When the second light component in the step (2) contains a second intermediate component, the side line (the position of the 2 nd to 10 th theoretical plates from top to bottom) of the ethylene glycol refining tower C-103 is used for extracting an ethylene glycol product, the top of the tower is used for extracting a third light component (comprising the second intermediate component), and the third heavy component in the tower bottom enters the diethylene glycol refining tower C-104;
when the second light component in the step (2) does not contain a second intermediate component, a side line (the position of a 2 nd to 10 th theoretical plate from top to bottom) of the ethylene glycol refining tower C-103 is used for extracting an ethylene glycol product, a third light component is extracted from the top of the tower, and a third heavy component at the tower bottom enters a diethylene glycol refining tower C-104; or the tower top of the ethylene glycol refining tower C-103 is used for extracting ethylene glycol products, and the third heavy component in the tower bottom enters the diethylene glycol refining tower C-104;
the theoretical plate number of the glycol refining tower C-103 is 10-40, the tower top operation pressure is-0.04 MPaG to-0.099 MPaG, the tower bottom operation temperature is 110-200 ℃, and the reflux ratio is 0.1-10;
(4) The side line (the position of the 3 rd to 10 th theoretical plates from top to bottom) of the diethylene glycol refining tower C-104 is used for extracting diethylene glycol products, the top of the tower is used for extracting fourth light components (comprising ethylene glycol and diethylene glycol), and the bottom of the tower is used for extracting fourth heavy components;
the theoretical plate number of the diethylene glycol refining tower C-104 is 5-30, the tower top operation pressure is-0.04 MPaG to-0.099 MPaG, the tower bottom operation temperature is 110-200 ℃, and the reflux ratio is 0.1-10.
In addition, boiling points of respective materials in the mixed alcohols referred to in the following examples and comparative examples are shown in Table 1.
TABLE 1
| Acetaldehyde | Water and its preparation method | Dioxahexacyclic ring | Ethylene glycol monoethyl ether | Ethylene glycol | Diethylene glycol | Triethylene glycol | Oligomer | |
| Boiling point/. Degree.C | 20.1 | 100 | 101 | 135 | 197.3 | 245 | 289.4 | ＞300 |
The following are exemplary but non-limiting examples of the invention:
examples 1 to 6 respectively provide a separation and recovery process of a by-product mixed alcohol of a polyester apparatus, which is based on the separation and recovery process in the specific embodiment, and the raw material composition of the specific mixed alcohol and the parameter conditions in the separation process are shown in tables 2 and 3, respectively.
TABLE 2
TABLE 3 Table 3
Comparative example 1
This comparative example provides a separation and recovery process of a byproduct mixed alcohol of a polyester plant, which is different from that of example 1 in that: and (3) the evaporation tower C-102 is not arranged, namely, the operation of the evaporation tower C-102 in the step (2) is not carried out, and the first heavy component in the tower kettle of the light component removal tower C-101 in the step (1) is directly introduced into the glycol refining tower C-103.
The separation and recovery process in the comparative example is adopted for separation, so that the packing is easy to block, the operation temperature of the tower kettle is increased, the required heat medium temperature is increased, and the reboiler of the tower kettle is easy to coke to influence the product quality; if the purity of ethylene glycol is 99.2wt%, the yield is less than 80%, and if the purity of diethylene glycol is 99.2wt%, the yield is less than 70%.
As can be seen from the above examples and comparative examples, the separation and recovery process of the invention removes the oligomer before the separation of the alcohols, avoids the blockage of the post tower plate or the filler, prolongs the service life of the device and saves the cost; the separation and recovery process is characterized in that aiming at the characteristics of more byproducts in polymerization reaction and larger influence of the change of the feed composition of mixed alcohol on the rectifying and separating effect, components are reasonably arranged, wherein the components comprise components with boiling points lower than that of water, intermediate components with boiling points between 110 ℃ and ethylene glycol, and extraction positions of the intermediate components with boiling points between ethylene glycol and diethylene glycol, the extraction amounts of the ethylene glycol and the diethylene glycol can be regulated under the condition of not changing a tower to meet the purity and the yield of the ethylene glycol and the diethylene glycol, the purity of the ethylene glycol is more than 99.2wt%, the yield is more than 95.8%, the purity of the diethylene glycol is more than 99.2wt%, and the yield is more than 86.8%.
The present invention is described in detail by the above examples, but the present invention is not limited to the above detailed methods, i.e., it does not mean that the present invention must be practiced depending on the above detailed methods. It should be apparent to those skilled in the art that any modifications, equivalent substitutions for operation of the present invention, addition of auxiliary operations, selection of specific modes, etc., are intended to fall within the scope of the present invention and the scope of the disclosure.
Claims (10)
1. The separation and recovery process of the byproduct mixed alcohol of the polyester device is characterized by comprising the following steps of:
(1) The mixed alcohol from the byproduct of the polyester device enters a light component removing tower, a first light component is extracted from the tower top, and a first heavy component in the tower bottom enters an evaporation tower;
(2) The tower bottom of the evaporation tower extracts a second heavy component, and the tower top extracts a second light component to enter an ethylene glycol refining tower;
(3) According to the composition of the second light component in the step (2), the side line of the ethylene glycol refining tower is used for extracting an ethylene glycol product, the top of the tower is used for extracting a third light component, and the third heavy component in the tower bottom enters the diethylene glycol refining tower;
or the tower top of the ethylene glycol refining tower extracts an ethylene glycol product, and the third heavy component in the tower bottom enters the diethylene glycol refining tower;
(4) And the side line of the diethylene glycol refining tower is used for extracting a diethylene glycol product, the top of the diethylene glycol refining tower is used for extracting a fourth light component, and the bottom of the diethylene glycol refining tower is used for extracting a fourth heavy component.
2. The separation and recovery process according to claim 1, wherein the mixed alcohol of step (1) comprises water, ethylene glycol, diethylene glycol, and oligomers;
preferably, the mixed alcohol in the step (1) comprises 1 to 10wt% of water, 70 to 95wt% of ethylene glycol, 5 to 20wt% of diethylene glycol and 0.01 to 10wt% of oligomer.
3. The separation and recovery process according to claim 2, wherein the mixed alcohol of step (1) further comprises at least one of a first intermediate component, a second intermediate component, a third intermediate component, or a fourth intermediate component;
preferably, the first intermediate component comprises a component having a boiling point lower than that of water, and a component having a boiling point between water and 110 ℃;
preferably, the second intermediate component comprises a component having a boiling point between 110 ℃ and ethylene glycol;
preferably, the third intermediate component comprises a component having a boiling point between ethylene glycol and diethylene glycol;
preferably, the fourth intermediate component comprises a component having a boiling point between diethylene glycol and the oligomer;
preferably, in the mixed alcohol in the step (1), the content of the first intermediate component is 0-5 wt%, the content of the second intermediate component is 0-5 wt%, the content of the third intermediate component is 0-5 wt%, and the content of the fourth intermediate component is 0-5 wt%.
4. The separation and recovery process according to claim 3, wherein the theoretical plate number of the light component removal column in the step (1) is 5 to 25;
preferably, the top operation pressure of the light component removal tower in the step (1) is-0.01 MPaG to-0.09 MPaG;
preferably, the tower bottom operation temperature of the light component removing tower in the step (1) is 110-180 ℃;
preferably, the reflux ratio of the light component removal tower in the step (1) is 0.1-10;
preferably, the first light component of step (1) comprises water and/or a first intermediate component.
5. The separation and recovery process according to claim 3 or 4, wherein the top operation pressure of the evaporation column in the step (2) is-0.04 mpa g to-0.099 mpa g;
preferably, the operation temperature of the tower bottom of the evaporation tower in the step (2) is 110-200 ℃;
preferably, the second heavy component of step (2) comprises an oligomer and/or a fourth intermediate component.
6. The separation and recovery process according to any one of claims 3 to 5, wherein the theoretical plate number of the ethylene glycol refining column in step (3) is 10 to 40;
preferably, the tower top operation pressure of the glycol refining tower in the step (3) is-0.04 MPaG to-0.099 MPaG;
preferably, the operation temperature of the tower bottom of the glycol refining tower in the step (3) is 110-200 ℃;
preferably, the reflux ratio of the glycol refining tower in the step (3) is 0.1-10.
7. The separation and recovery process according to any one of claims 3 to 6, wherein when the second intermediate component is not contained in the second light component in the step (3), a glycol product is taken out from a side line of the glycol refining tower, a third light component is taken out from the top of the tower, and a third heavy component in the tower bottom enters the diethylene glycol refining tower; or the tower top of the ethylene glycol refining tower extracts an ethylene glycol product, and the third heavy component in the tower bottom enters the diethylene glycol refining tower;
preferably, when the second light component in the step (3) contains the second intermediate component, the side line of the ethylene glycol refining tower is used for extracting an ethylene glycol product, the top of the tower is used for extracting a third light component, and the third heavy component in the tower bottom enters the diethylene glycol refining tower;
preferably, the ethylene glycol product in the step (3) is extracted from the side line position of the 2 nd to 10 th theoretical plates from top to bottom;
preferably, the third light component of step (3) comprises a second intermediate component.
8. The separation and recovery process according to any one of claims 1 to 7, wherein the theoretical plate number of the diethylene glycol refining column in step (4) is 5 to 30;
preferably, the overhead operating pressure of the diethylene glycol refining column of step (4) is from-0.04 MPaG to-0.099 MPaG;
preferably, the operation temperature of the tower bottom of the diethylene glycol refining tower in the step (4) is 110-200 ℃;
preferably, the reflux ratio of the diethylene glycol refining tower in the step (4) is 0.1-10;
preferably, the diethylene glycol product of step (4) is withdrawn at the side line position of the theoretical plates 3 to 10 from top to bottom;
preferably, the fourth light component of step (4) comprises ethylene glycol and diethylene glycol.
9. The separation and recovery process according to any one of claims 1 to 8, wherein the evaporation tower of step (2) comprises any one of an evaporation tower without a reflux belt wire mesh, an evaporation tower without a reflux belt one section of packing, an evaporation tower with a reflux belt one section of packing, or an evaporation tower with a reflux belt tray;
preferably, in the evaporation tower without the reflux and with the one-section packing and the evaporation tower with the reflux and the one-section packing, the heights of the packing are independently 1-3 m;
preferably, the theoretical plate number of the evaporation tower with the reflux band tower plate is 2-10.
10. The separation and recovery process according to any one of claims 1 to 9, wherein the separation and recovery process of the by-product mixed alcohol of the polyester unit is a continuous process.
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| CN105085165A (en) * | 2014-05-14 | 2015-11-25 | 中国石油化工股份有限公司 | Ethylene glycol and diethylene glycol separation method |
| CN107365253A (en) * | 2017-07-18 | 2017-11-21 | 百川化工(如皋)有限公司 | Propylene glycol methyl ether acetate rectification system and rectification method thereof |
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| CN112679352A (en) * | 2019-10-18 | 2021-04-20 | 中国石油化工股份有限公司 | Refining method and system for mixed material flow containing dimethyl carbonate |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105085165A (en) * | 2014-05-14 | 2015-11-25 | 中国石油化工股份有限公司 | Ethylene glycol and diethylene glycol separation method |
| CN107915615A (en) * | 2016-10-08 | 2018-04-17 | 万华化学集团股份有限公司 | The method that the MIBK of purification is prepared by industrial by-product waste liquid acetone |
| CN107365253A (en) * | 2017-07-18 | 2017-11-21 | 百川化工(如皋)有限公司 | Propylene glycol methyl ether acetate rectification system and rectification method thereof |
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