CN112694639A - Method and device for purifying polymerization liquid in EVOH production process - Google Patents
Method and device for purifying polymerization liquid in EVOH production process Download PDFInfo
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Abstract
The invention relates to a method and a device for purifying polymerization liquid in an EVOH production process, which comprises the following steps: feeding the polymer liquid material flow containing the ethylene-vinyl acetate copolymer into a flash tank, and separating to obtain a crude ethylene material flow containing ethylene and a second polymer liquid material flow containing the ethylene-vinyl acetate copolymer; pressurizing the second polymerization liquid material flow through a pressurizing pump to obtain a pressurized polymerization liquid material flow; feeding the pressurized polymer liquid material flow into the upper part of a demonomerization tower, contacting the pressurized polymer liquid material flow with a gas-phase methanol material flow fed from the lower part in the demonomerization tower, obtaining a dilute vinyl acetate material flow mainly containing vinyl acetate and methanol at the tower top, and obtaining a purified polymer liquid material flow at the tower bottom; has the advantages of high vinyl acetate removal rate, good resin product chromaticity and low energy consumption in the separation process. Can be used in the separation process of preparing olefin products by using synthesis gas.
Description
Technical Field
The invention relates to a method and a device for purifying polymerization liquid in an EVOH production process.
Technical Field
Ethylene-vinyl acetate copolymer (EVOH), polyvinylidene chloride (PVDC) and Polyamide (PA) are called world three-high barrier resin, the barrier property of the resin is about ten thousand times of that of common polyethylene, and the resin is widely applied to the fields of packaging materials, automobile oil tanks, oxygen-resistant floor heating pipes, textile and medical materials and the like. In 2011, the worldwide annual capacity of the EVOH is about 12.6 ten thousand tons, the annual consumption total is about 11 ten thousand tons, the domestic annual consumption total is about 7300 tons, and the selling price is about 6 ten thousand yuan/ton. It is expected that by 2015 and 2020, world EVOH demand will reach 13 and 18 million tons, respectively, and asian regions will be the regions where EVOH is the fastest growing. The current EVOH production technology is mainly monopolized by Nippon Coli, synthetic chemistry and Taiwan Changchun.
EVOH is generally prepared by polymerizing ethylene and vinyl acetate by a conventional method such as emulsion polymerization, solution polymerization or suspension polymerization, and then saponifying the resulting product. In the copolymerization process of ethylene and vinyl acetate, the reaction efficiency is low, so that besides ethylene-vinyl acetate copolymer, a large amount of methanol as a solution, a large amount of unreacted ethylene and vinyl acetate exist in the outlet of the reactor, wherein a large amount of unreacted ethylene can be recovered after decompression flash evaporation, and the unreacted vinyl acetate needs to be recovered through a recovery process.
CN102942649A discloses a preparation method of an ethylene vinyl alcohol copolymer, which comprises the following steps: dissolving vinyl acetate and an oil-soluble initiator into monohydric alcohol with 1-5 carbon atoms, introducing ethylene gas to keep the reaction pressure at 5-50 atmospheric pressure, stirring and heating to 45-75 ℃, stirring at the speed of 25-500 rpm, and keeping the temperature to react for 0.5-10 hours to obtain an EVA solution; and adding 1-40% of alkali liquor into the EVA solution, stirring and heating to 50-85 ℃, keeping the temperature for reaction for 0.5-12 hours, cooling to room temperature, adding water for cleaning, and drying at 30-200 ℃ to obtain the EVOH.
CN 204607899A has disclosed ethylene recovery system in EVOH production process, including the flash tank that is connected with feed line and ejection of compact pipeline simultaneously, the compressor, the condenser, vapour and liquid separator, the EVOH solution from polymerization system will be from the feed line lets in to the flash tank and carries out the flash distillation, liquid component flows into downstream device through ejection of compact pipeline after the flash distillation, ethylene gas gets into tubular condenser condensation to 10 ℃, the gas-liquid mixture after the condensation gets into vapour and liquid separator, mix in vapour and liquid separator and the fresh raw materials ethylene that lets in through the ethylene inlet line, the liquid that the separation produced gets back to the flash tank, ethylene gas is then directly let in to the compressor, get back to polymerization system cyclic utilization after the compression. The utility model is only a device for recycling unreacted ethylene.
The invention provides a method and a device for purifying polymerization liquid in an EVOH production process, which aim to solve the problem in the prior published patents, wherein most of the prior published patents focus on the EVOH production preparation process, and the prior published patents focus on less problems of purification of the polymerization liquid in the EVOH production process.
Disclosure of Invention
The invention relates to a method and a device for purifying a polymer liquid in an EVOH (ethylene-vinyl alcohol) production process, which mainly solve the problem of purifying the polymer liquid in the EVOH production process, can be used for a separation process in the EVOH production process, and have the advantages of simple flow, high removal rate of ethylene and vinyl acetate, low energy consumption and good product chromaticity.
In order to solve the problems, the technical scheme adopted by the invention is as follows:
a) feeding the polymer liquid material flow containing the ethylene-vinyl acetate copolymer into a flash tank, and separating to obtain a crude ethylene material flow containing ethylene and a second polymer liquid material flow containing the ethylene-vinyl acetate copolymer;
b) pressurizing the second polymerization liquid material flow through a pressurizing pump to obtain a pressurized polymerization liquid material flow;
c) the pressurized polymer liquid material flow is sent to the upper part of the demonomerization tower, and after contacting with the gas phase methanol material flow sent from the lower part in the demonomerization tower, a dilute vinyl acetate material flow mainly containing vinyl acetate and methanol is obtained at the tower top, and a purified polymer liquid material flow is obtained at the tower bottom.
In the technical scheme of the invention, the polymer liquid stream contains ethylene and vinyl acetate.
In the technical scheme of the invention, the content of the ethylene-vinyl acetate copolymer in the polymerization liquid stream is more than or equal to 20 percent, preferably more than or equal to 25 percent in percentage by weight.
In the technical scheme of the invention, the flash tank is provided with stirring mainly for fully volatilizing the ethylene component wrapped in the ethylene-vinyl acetate copolymer, so that the removal efficiency of the ethylene component can be increased on one hand, and the ethylene-vinyl acetate copolymer can be uniformly mixed on the other hand, thereby preventing the product chromaticity from being influenced by local overheating.
According to the technical scheme, the crude ethylene material flow is cooled by a vertical cooler and then sent to a downstream separation device, other components are carried when ethylene components volatilize, if ethylene needs to be recycled, a device for purifying ethylene needs to be added, when the ethylene components at the top of a flash tank are discharged from the flash tank, a vertical heat exchanger is adopted for condensation, the condensation is carried out to 12-40 ℃, the other components carried by the ethylene can directly return to the flash tank again, a gas-liquid separation tank does not need to be arranged at the outlet of a condenser, the purity of recycled ethylene is greatly improved, and the recycled ethylene can be directly recycled after pressurization.
In the technical scheme of the invention, the ratio of the vinyl acetate in the gas-phase methanol material flow and the polymerization liquid material flow is 10: 1-1.5: 1, preferably 8: 1-1.5: 1 in percentage by weight.
In the technical scheme of the invention, the temperature of the gas-phase methanol material flow is 65-120 ℃, and preferably 65-110 ℃.
In the technical scheme of the invention, the lower part of the demonomerization tower is fed with the gas-phase methanol material flow, which is mainly used for supplementing the insufficient gas phase in the demonomerization tower and fully recovering the vinyl acetate in the product material flow.
In the invention, the ethylene-vinyl acetate copolymer has high viscosity, is easy to discolor at high temperature (more than 120 ℃) and influences the chromaticity of the product, and the copolymer and methanol mixed solution has good fluidity at 50-110 ℃. If the single stripping tower is operated according to a common rectifying tower, in order to fully recover the vinyl acetate, the content of methanol from the top of the tower to the bottom of the tower is gradually reduced, the viscosity is gradually increased, the heat transfer effect is also poor, and a heat exchanger at the bottom of the tower is easy to be blocked or partially overheated, so that the normal operation cannot be realized or the product chromaticity is influenced; on the other hand, the load of a reboiler of the tower kettle can be greatly reduced, a small amount of or no gas phase is provided by the reboiler of the tower kettle in the single removing tower, the gas phase in the single removing tower is provided by gas phase methanol material flow which is sent from the outside, and compared with the method that pure methanol is changed into the gas phase from a liquid phase and the methanol in the tower kettle liquid containing the ethylene-vinyl acetate copolymer is changed into the gas phase, the heat transfer efficiency is high, the heat exchange area is small, the product chromaticity is not influenced, dead zones or blockage points are not easy to occur, and the energy consumption is.
In the technical scheme of the invention, the operating pressure of the demonomerization tower is 0-290 KPaG, and preferably 0-190 KPaG.
In the technical scheme of the invention, the operation temperature of the top of the demonomerization tower is 60-105 ℃, and preferably 60-95 ℃.
In the technical scheme of the invention, whether the reboiler of the tower kettle of the demonomerization tower is required to be optional or not is provided.
The invention also provides a device for purifying the polymerization liquid in the EVOH production process, which comprises:
1) a flash tank; configured to receive a polymerization liquid stream comprising ethylene vinyl acetate copolymer, discharge a crude ethylene stream at the top of the tank, and discharge a second polymerization liquid stream at the bottom of the tank;
2) a pressure pump; configured to receive the second polymerization liquid stream and discharge a pressurized polymerization liquid stream;
3) a demonomerization tower; the device is configured to receive a pressurized polymer liquid material flow at the upper part, receive a gas-phase methanol material flow at the lower part, discharge a dilute vinyl acetate material flow at the tower top and discharge a purified polymer liquid material flow at the tower bottom;
4) a reboiler; configured to receive a reboiler feed stream and discharge a reboiler discharge stream;
in the technical scheme of the invention, a cooler is arranged at the top of the flash tank.
All publications, patent applications, patents, and other references mentioned in this specification are herein incorporated by reference in their entirety. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present specification, including definitions, will control.
When the specification concludes with claims with the heading "known to those skilled in the art", "prior art", or the like, to derive materials, substances, methods, procedures, devices, or components, etc., it is intended that the subject matter derived from the heading encompass those conventionally used in the art at the time of filing this application, but also include those that are not currently in use, but would become known in the art to be suitable for a similar purpose.
In the context of the present specification, anything or things which are not mentioned, except where explicitly stated, are directly applicable to those known in the art without any changes. Moreover, any embodiment described herein may be freely combined with one or more other embodiments described herein, and the technical solutions or concepts resulting therefrom are considered part of the original disclosure or original disclosure of the invention, and should not be considered as new matters not disclosed or contemplated herein, unless a person skilled in the art would consider such a combination to be clearly unreasonable.
The present invention will be further illustrated by the following examples, but is not limited to these examples.
Drawings
FIG. 1 shows a method for purifying polymerization liquid in EVOH production process.
FIG. 1 depicts the following:
101 is a polymer liquid stream
102 is a crude ethylene stream
103 is a second polymerization liquid stream
104 is a pressurized polymerization liquid stream
105 is a gas phase methanol stream
106 is a dilute vinyl acetate stream
107 is a purified post-polymerization liquid stream
108 is a reboiler feed stream
11 is a flash tank
12 is a pressure pump
13 is a demonomerization tower
14 is a reboiler
In FIG. 1, a polymerization liquid stream 101 containing ethylene-vinyl acetate copolymer is fed to a flash drum 11 and separated to obtain a crude ethylene stream 102 containing ethylene and a second polymerization liquid stream 103 containing ethylene-vinyl acetate copolymer; second polymerization liquid stream 103 is pressurized by pressure pump 12 to provide pressurized polymerization liquid stream 104; the pressurized polymer liquid material flow 104 is sent to the upper part of the demonomerization tower 13, and after heat and mass transfer with the gas phase methanol material flow 105 sent from the lower part in the demonomerization tower 13, a dilute vinyl acetate material flow 106 mainly containing vinyl acetate and methanol is obtained at the tower top, and a purified polymer liquid material flow 107 is obtained at the tower bottom. Reboiler feed stream 108 extracted from the bottom of the demonomerization tower 13 is sent into the reboiler 14, and reboiler feed stream 109 obtained from the outlet is returned to the demonomerization tower.
Detailed Description
The technical scheme of the invention is adopted by taking the product flow of 7000kg/h as a reference, and the description is carried out by the embodiment.
[ example 1 ]
The product stream comprises, in weight percent: 40.7% of vinyl acetate, 1.3% of ethylene, 19.7% of methanol and 38.3% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 6:1, by weight.
The operating pressure of the single stripping tower is 5KPaG, the top temperature of the tower is 64.5, the temperature of the tower kettle is 78.4, and the load of a reboiler of the tower kettle is 78.4 KW.
The temperature of the gas phase methanol stream was 83 ℃.
The purified polymer liquid material flow has the ethylene content of 0 and the vinyl acetate content of 0, and the post-processed product has good chromaticity.
[ example 2 ]
The product stream comprises, in weight percent: 40.7% of vinyl acetate, 1.3% of ethylene, 19.7% of methanol and 38.3% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 6:1, by weight.
The operating pressure of the single-removing tower is 10KPaG, the top temperature of the tower is 65.7, the temperature of the tower bottom is 79.7, and the load of a reboiler at the tower bottom is 73.2 KW.
The temperature of the gas phase methanol stream was 83 ℃.
The purified polymer liquid material flow has the ethylene content of 0 and the vinyl acetate content of 0, and the post-processed product has good chromaticity.
[ example 3 ]
The product stream comprises, in weight percent: 40.7% of vinyl acetate, 1.3% of ethylene, 19.7% of methanol and 38.3% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 6:1, by weight.
The operating pressure of the demonomerization tower is 20KPaG, the top temperature of the tower is 67.9, the temperature of the tower bottom is 82.2, and the load of a reboiler at the tower bottom is 99.0 KW.
The temperature of the gas phase methanol stream was 83 ℃.
The purified polymer liquid material flow has the ethylene content of 0 and the vinyl acetate content of 0, and the post-processed product has good chromaticity.
[ example 4 ]
The product stream comprises, in weight percent: 40.7% of vinyl acetate, 1.3% of ethylene, 19.7% of methanol and 38.3% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 6:1, by weight.
The operating pressure of the single-removing tower is 40KPaG, the top temperature of the tower is 71.9, the temperature of the tower bottom is 86.6, and the load of a reboiler at the tower bottom is 145.9 KW.
The temperature of the gas phase methanol stream was 83 ℃.
The purified polymer liquid material flow has the ethylene content of 0 and the vinyl acetate content of 0, and the post-processed product has good chromaticity.
[ example 5 ]
The product stream comprises, in weight percent: 40.7% of vinyl acetate, 1.3% of ethylene, 19.7% of methanol and 38.3% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 6:1, by weight.
The operating pressure of the single removal tower is 60KPaG, the top temperature of the tower is 75.5, the temperature of the tower kettle is 90.6, and the load of a reboiler of the tower kettle is 187.7 KW.
The temperature of the gas phase methanol stream was 83 ℃.
The purified polymer liquid material flow has the ethylene content of 0 and the vinyl acetate content of 0, and the post-processed product has good chromaticity.
[ example 6 ]
The product stream comprises, in weight percent: 40.7% of vinyl acetate, 1.3% of ethylene, 19.7% of methanol and 38.3% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 6:1, by weight.
The operating pressure of the single-removing tower is 80KPaG, the top temperature of the tower is 78.7, the temperature of the tower bottom is 94.2, and the load of a reboiler at the tower bottom is 225.4 KW.
The temperature of the gas phase methanol stream was 83 ℃.
The purified polymer liquid material flow has the ethylene content of 0 and the vinyl acetate content of 0, and the post-processed product has good chromaticity.
[ example 7 ]
The product stream comprises, in weight percent: 40.7% of vinyl acetate, 1.3% of ethylene, 19.7% of methanol and 38.3% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 6:1, by weight.
The operating pressure of the single-removing tower is 100KPaG, the top temperature of the tower is 81.7, the temperature of the tower bottom is 97.5, and the load of a reboiler at the tower bottom is 260.0 KW.
The temperature of the gas phase methanol stream was 83 ℃.
The purified polymer liquid material flow has the ethylene content of 0 and the vinyl acetate content of 0, and the post-processed product has good chromaticity.
[ example 8 ]
The product stream comprises, in weight percent: 40.7% of vinyl acetate, 1.3% of ethylene, 19.7% of methanol and 38.3% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 6:1, by weight.
The operating pressure of the demonomerization tower is 140KPaG, the top temperature of the tower is 86.9, the temperature of the tower bottom is 103.3, and the load of the reboiler at the tower bottom is 321.8 KW.
The temperature of the gas phase methanol stream was 83 ℃.
The purified polymer liquid material flow has the ethylene content of 0 and the vinyl acetate content of 0, and the post-processed product has good chromaticity.
[ example 9 ]
The product stream comprises, in weight percent: 40.7% of vinyl acetate, 1.3% of ethylene, 19.7% of methanol and 38.3% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 6:1, by weight.
The operating pressure of the single-removing tower is 180KPaG, the top temperature of the tower is 91.5, the temperature of the tower kettle is 108.5, and the load of a reboiler at the tower kettle is 375.8 KW.
The temperature of the gas phase methanol stream was 83 ℃.
The purified polymer liquid material flow has the ethylene content of 0 and the vinyl acetate content of 0, and the post-processed product has good chromaticity.
[ example 10 ]
The product stream comprises, in weight percent: 40.7% of vinyl acetate, 1.3% of ethylene, 19.7% of methanol and 38.3% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 6:1, by weight.
The operating pressure of the demonomerization tower is 190KPaG, the top temperature of the tower is 92.6, the temperature of the tower bottom is 109.7, and the load of the reboiler at the tower bottom is 388.4 KW.
The temperature of the gas phase methanol stream was 83 ℃.
The purified polymer liquid material flow has the ethylene content of 0 and the vinyl acetate content of 0, and the post-processed product has good chromaticity.
[ example 11 ]
The product stream comprises, in weight percent: 42.35% of vinyl acetate, 1.3% of ethylene, 21.35% of methanol and 35% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 6:1, by weight.
The operating pressure of the demonomerization tower is 20KPaG, the top temperature of the tower is 67.8, the temperature of the tower bottom is 80.5, and the load of the reboiler at the tower bottom is 69.64 KW.
The temperature of the gas phase methanol stream was 83 ℃.
The purified polymer liquid material flow has the ethylene content of 0 and the vinyl acetate content of 0, and the post-processed product has good chromaticity.
[ example 12 ]
The product stream comprises, in weight percent: 44.85% of vinyl acetate, 1.3% of ethylene, 23.85% of methanol and 30% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 6:1, by weight.
The operating pressure of the demonomerization tower is 20KPaG, the top temperature of the tower is 67.7, the temperature of the tower bottom is 78.3, and the load of the reboiler at the tower bottom is 29.67 KW.
The temperature of the gas phase methanol stream was 83 ℃.
The purified polymer liquid material flow has the ethylene content of 0 and the vinyl acetate content of 0, and the post-processed product has good chromaticity.
[ example 13 ]
The product stream comprises, in weight percent: 40.7% of vinyl acetate, 1.3% of ethylene, 19.7% of methanol and 38.3% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 8:1, by weight.
The operating pressure of the demonomerization tower is 20KPaG, the top temperature of the tower is 68.2, the temperature of the tower bottom is 82.2, and the load of a reboiler at the tower bottom is 18.3 KW.
The temperature of the gas phase methanol stream was 98 ℃.
The purified polymer liquid material flow has the ethylene content of 0 and the vinyl acetate content of 0, and the post-processed product has good chromaticity.
[ example 14 ]
The product stream comprises, in weight percent: 40.7% of vinyl acetate, 1.3% of ethylene, 19.7% of methanol and 38.3% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 4:1, by weight.
The operating pressure of the demonomerization tower is 20KPaG, the top temperature of the tower is 67.1, the temperature of the tower bottom is 82.2, and the load of the reboiler at the tower bottom is 3449.8 KW.
The temperature of the gas phase methanol stream was 68 ℃.
The purified polymer liquid material flow has the ethylene content of 0 and the vinyl acetate content of 0, and the post-processed product has good chromaticity.
[ example 15 ]
The product stream comprises, in weight percent: 40.7% of vinyl acetate, 1.3% of ethylene, 19.7% of methanol and 38.3% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 2:1, by weight.
The operating pressure of the single-component removal tower is 20KPaG, the top temperature of the tower top is 64.9, the temperature of the tower bottom is 80.2, and the load of a reboiler at the tower bottom is 626.62 KW.
The temperature of the gas phase methanol stream was 68 ℃.
The purified polymer liquid material flow has the ethylene content of 0 and the vinyl acetate content of 0, and the post-processed product has good chromaticity.
[ COMPARATIVE EXAMPLE 1 ]
The product stream comprises, in weight percent: 40.7% of vinyl acetate, 1.3% of ethylene, 19.7% of methanol and 38.3% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 6:1, by weight.
The operating pressure of the demonomerization tower is 300KPaG, the top temperature of the tower is 106.4, the temperature of the tower bottom is 125.4, and the load of the reboiler at the tower bottom is 5747.3 KW.
The temperature of the gas phase methanol stream was 68 ℃.
The purified polymer liquid material flow has 0 ethylene content and 0 vinyl acetate content, and the chroma of the post-processed product is not good due to the high temperature of the tower kettle.
[ COMPARATIVE EXAMPLE 2 ]
The product stream comprises, in weight percent: 40.7% of vinyl acetate, 1.3% of ethylene, 19.7% of methanol and 38.3% of ethylene-vinyl acetate copolymer.
The ratio of vinyl acetate in the gas phase methanol stream to the polymer liquid stream was 1:1, by weight.
The operating pressure of the demonomerization tower is 20KPaG, the top temperature of the tower is 62.6, the temperature of the tower bottom is 82.0, and the load of a reboiler at the tower bottom is 51.2 KW.
The temperature of the gas phase methanol stream was 56 ℃.
The ethylene content in the purified polymer liquid material flow is 0, the vinyl acetate content is 8.49 percent, and the product chroma after post processing is good.
Claims (12)
1. A method for purifying polymerization liquid in an EVOH production process comprises the following steps:
a) feeding the polymer liquid material flow containing the ethylene-vinyl acetate copolymer into a flash tank, and separating to obtain a crude ethylene material flow containing ethylene and a second polymer liquid material flow containing the ethylene-vinyl acetate copolymer;
b) pressurizing the second polymerization liquid stream to obtain a pressurized polymerization liquid stream;
c) feeding the pressurized polymer liquid material flow into the upper part of a demonomerization tower, contacting the pressurized polymer liquid material flow with a gas-phase methanol material flow fed from the lower part in the demonomerization tower, obtaining a dilute vinyl acetate material flow mainly containing vinyl acetate and methanol at the tower top, and obtaining a purified polymer liquid material flow at the tower bottom; the weight ratio of the vinyl acetate in the gas-phase methanol material flow and the polymerization liquid material flow is 10: 1-1.5: 1.
2. A method of polymer purge in EVOH production process according to claim 1, characterized in that the polymer stream contains ethylene, vinyl acetate.
3. Method for purification of a polymerization liquid in EVOH production process according to claim 1, wherein the ethylene-vinyl acetate copolymer content of the polymerization liquid stream is equal to or higher than 20%, preferably equal to or higher than 25% in weight percentage.
4. Method for purification of polymerization liquid in EVOH production process according to claim 1, characterized in that the flash tank is equipped with stirring.
5. A method for purification of polymerization liquid in EVOH production process according to claim 1, characterized in that the crude ethylene stream is cooled by a cooler before being sent to a downstream separation device.
6. The method of claim 1, wherein the weight ratio of the methanol vapor stream to the vinyl acetate in the polymer stream is 8:1 to 1.5: 1.
7. Method for purification of polymerization liquid in EVOH production process according to claim 1, characterized in that the temperature of the gaseous methanol stream is 65-120 ℃, preferably 65-110 ℃.
8. The method for purifying polymerization liquid in EVOH production process according to claim 1, characterized in that the operating pressure of the demonomerization tower is 0-290 KPaG, preferably 0-190 KPaG.
9. Method for purification of polymerization liquid in EVOH production process according to claim 1, characterized in that the operating temperature of the demonomerization top is 60-105 ℃, preferably 60-95 ℃.
10. The method of claim 1, wherein the de-monoseparator comprises a reboiler.
11. An apparatus for purifying polymerization liquid in EVOH production process, comprising:
1) a flash tank; configured to receive a polymerization liquid stream comprising ethylene vinyl acetate copolymer, discharge a crude ethylene stream at the top of the tank, and discharge a second polymerization liquid stream at the bottom of the tank;
2) a pressure pump; configured to receive the second polymerization liquid stream and discharge a pressurized polymerization liquid stream;
3) a demonomerization tower; the device is configured to receive a pressurized polymer liquid material flow at the upper part, receive a gas-phase methanol material flow at the lower part, discharge a dilute vinyl acetate material flow at the tower top and discharge a purified polymer liquid material flow at the tower bottom;
4) a reboiler; configured to receive a reboiler feed stream and discharge a reboiler discharge stream.
12. Apparatus for purification of polymerization liquid in EVOH production process according to claim 11, characterized in that the top of the flash tank is provided with a vertical cooler configured to cool the crude ethylene stream.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911009088.2A CN112694639B (en) | 2019-10-23 | 2019-10-23 | Method and device for purifying polymerization liquid in EVOH production process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911009088.2A CN112694639B (en) | 2019-10-23 | 2019-10-23 | Method and device for purifying polymerization liquid in EVOH production process |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112694639A true CN112694639A (en) | 2021-04-23 |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6045661A (en) * | 1998-05-20 | 2000-04-04 | Phillips Petroleum Company | Process and apparatus for recovering diluent, monomer, and comonomer from a polymerization reactor effluent |
| CN102451572A (en) * | 2010-11-03 | 2012-05-16 | 中国石油化工股份有限公司 | Method for separating acetic acid from water by rectification of acetic acid dehydrating tower |
| CN104030921A (en) * | 2013-07-05 | 2014-09-10 | 中石化上海工程有限公司 | Method for separating vinyl acetate |
| CN104109070A (en) * | 2013-04-16 | 2014-10-22 | 中国石油化工股份有限公司 | Methanol-to-propylene product separation method |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6045661A (en) * | 1998-05-20 | 2000-04-04 | Phillips Petroleum Company | Process and apparatus for recovering diluent, monomer, and comonomer from a polymerization reactor effluent |
| CN102451572A (en) * | 2010-11-03 | 2012-05-16 | 中国石油化工股份有限公司 | Method for separating acetic acid from water by rectification of acetic acid dehydrating tower |
| CN104109070A (en) * | 2013-04-16 | 2014-10-22 | 中国石油化工股份有限公司 | Methanol-to-propylene product separation method |
| CN104030921A (en) * | 2013-07-05 | 2014-09-10 | 中石化上海工程有限公司 | Method for separating vinyl acetate |
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