WO2024068783A1 - Procédé de préparation d'un copolymère à partir d'au moins un composé vinylique aromatique - Google Patents

Procédé de préparation d'un copolymère à partir d'au moins un composé vinylique aromatique Download PDF

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Publication number
WO2024068783A1
WO2024068783A1 PCT/EP2023/076791 EP2023076791W WO2024068783A1 WO 2024068783 A1 WO2024068783 A1 WO 2024068783A1 EP 2023076791 W EP2023076791 W EP 2023076791W WO 2024068783 A1 WO2024068783 A1 WO 2024068783A1
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Prior art keywords
heat exchanger
condensate
pump
liquid
vapor stream
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PCT/EP2023/076791
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German (de)
English (en)
Inventor
Wolfgang Fischer
Brian J. BANASZAK
Koen TAELMAN
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Ineos Styrolution Group Gmbh
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Publication of WO2024068783A1 publication Critical patent/WO2024068783A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/04—Polymerisation in solution
    • C08F2/06—Organic solvent
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/01—Processes of polymerisation characterised by special features of the polymerisation apparatus used
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
    • C08F212/02—Monomers containing only one unsaturated aliphatic radical
    • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
    • C08F212/06—Hydrocarbons
    • C08F212/08—Styrene
    • C08F212/10—Styrene with nitriles

Definitions

  • the invention relates to a process for producing a styrene copolymer starting from at least one aromatic compound, in particular styrene and/or alpha-methylstyrene, and at least one further monomer from the group consisting of acrylonitrile and methacrylate, the process involving the polymerization of the at least one aromatic vinyl compound and of the at least one further monomer in at least one reactor in the presence of at least one organic solvent, the separation of volatile components to obtain a vapor stream, the condensation of at least parts of the vapor stream, and the generation of a negative pressure.
  • the invention further relates to a device for carrying out the method.
  • vapor describes volatile, gaseous products that arise during chemical reactions, distillation of liquid mixtures, evaporation, degassing or drying.
  • the volatile components of vapor can include aromatic vinyl monomers such as styrene or alpha-methylstyrene, vinyl cyanide monomers such as acrylonitrile, methacrylate monomers such as methyl methacrylate (MMA) and/or organic solvents such as ethylbenzene, but also water vapor, especially in small quantities.
  • heat exchangers such as capacitors.
  • the amount of monomers such as styrene, alpha-methylstyrene, methyl methacrylate and/or organic solvent such as ethylbenzene discharged from the process can be reduced by using liquid ring pumps to create a vacuum, which are filled with organic liquids containing the monomers used in the reaction and solvents.
  • the copolymers obtained such as styrene-acrylonitrile copolymers (SAN copolymers), in particular alpha-methylstyrene-acrylonitrile copolymers (AMSAN copolymers) and/or styrene-methyl methacrylate copolymers (SMMA copolymers), have excellent formability, rigidity and durability They also preserve them when exposed to the elements.
  • SAN copolymers styrene-acrylonitrile copolymers
  • AMSAN copolymers alpha-methylstyrene-acrylonitrile copolymers
  • SMMA copolymers styrene-methyl methacrylate copolymers
  • the copolymers can be used in various fields including the manufacture of automobiles, computers, printers, copiers, household appliances, audio systems and electrical components.
  • a copolymer of an aromatic vinyl compound and a vinyl cyanide compound and/or methacrylate is typically prepared by reacting the monomers in an organic solvent
  • the polymerization product initially contains unreacted monomers and organic solvent, which must preferably be removed in an environmentally friendly manner.
  • the copolymerization can be carried out in one or more reactors.
  • the polymerization product obtained is transferred to an evaporation tank, which can also be referred to as a degassing tank, and volatile components such as residual monomers and organic solvent are separated off under vacuum. The condensation of the separated volatile components takes place using coolers. Furthermore, purification is carried out in order to obtain the copolymer end product in the highest possible yield.
  • EP 3 689 923 B1 describes a process for producing a polymer from an aromatic vinyl compound and a vinyl cyanide compound. A freshly added organic solvent is sprayed onto separated volatile components. The separation of volatile components from the product mixture, which contains polymer, residual monomers and organic solvent, takes place using an evaporation tank and by condensing the separated volatile components in one or two condensers connected in series. Improved condensation can be achieved by increasing the pressure and reducing the cooling temperature.
  • EP 3 689 923 B1 lists installation limitations as limits when lowering the temperature of a feed refrigerant in condensation, which leads to the discharge of non-condensed volatile components from the process.
  • the condensation efficiency is reduced when the amount of low boiling point vinyl cyanide monomers is increased.
  • US 4,555,384 discloses a process and apparatus for the continuous bulk polymerization of styrene and alkenyl nitrile monomers. Steam containing monomers is taken directly from the polymerization reactor and fed to a condenser.
  • EP 3 689 919 A1 relates to the preparation of a polymer from an aromatic vinyl compound and a vinyl cyanide compound, wherein an evaporated part of the reaction mixture is also led from the reactor into a condenser.
  • Liquid ring pumps are known to be used to generate vacuum. Condensable components in the inlet flow to the vacuum pump can condense in the liquid ring. If water is used as the liquid in the liquid ring, it is typically contaminated, especially if the gas sucked in contains organic components. This produces waste water that must be discarded and cleaned. This results in emissions into the environment that must be minimized. Furthermore, the use of water in a liquid ring pump limits the temperature ranges for heat exchangers to cool the liquid in the liquid ring pump system, since undesirable ice formation can occur at temperatures below 0°C.
  • the task is to provide an energy-efficient and low-emission process and a corresponding device in which the separation and disposal of waste water and possibly condensed vapors is avoided.
  • the invention relates to a process for producing a copolymer starting from at least one aromatic vinyl compound, in particular styrene and/or alpha-methylstyrene, and at least one further monomer from the group consisting of acrylonitrile and methacrylate, the process comprising the following steps: a) polymerization of the at least one aromatic vinyl compound and the at least one further monomer in at least one reactor in the presence of at least one organic solvent, whereby a polymerization product is obtained which contains the copolymer, residual monomers, the at least one organic solvent and optionally oligomers, b) separation of volatile components from the polymerization product obtained in step a), whereby the separation takes place in a degassing vessel at a negative pressure of 1 to 150 mbar, in particular of 10 to 100 mbar, absolute and the polymerization product is heated in a first heat exchanger and the first heat exchanger is provided with a first media inlet temperature of more than 200°C, in particular in a range of 2
  • the invention also relates to a device for carrying out the method according to the invention, comprising a reactor, a first heat exchanger, a degassing vessel, optionally a column with a column head space, a second heat exchanger with a gas outlet and a liquid outlet, a third heat exchanger and a vacuum system, these are connected downstream in the specified order,
  • the third heat exchanger has an inlet space, in particular a head space, and a collection space, in particular a sump space, and is preferably arranged vertically and the vacuum system is fluidly connected to the collection space of the third heat exchanger
  • the vacuum system has at least one Pump, which is designed as a liquid ring pump system, comprises an overflow and a pump heat exchanger and the pump heat exchanger is arranged downstream on the high-pressure side of the pump and is connected to the low-pressure side of the pump via a return line.
  • a supply line is preferably arranged between the overflow and the pump heat exchanger, via which the liquid is added to the vacuum system, in
  • the process or device according to the invention enables the condensation of the vapor stream, i.e. the volatile components from the polymerization product, to be carried out with lower emissions.
  • the condensation of the vapor stream i.e. the volatile components from the polymerization product
  • the generation of waste water is eliminated.
  • the formation of wastewater can be prevented by operating the liquid ring pump system with a liquid that is taken from the pressure side of the pump, i.e. the condensate from the process is returned and used as a liquid ring. Accordingly, an organic liquid is used in the vacuum system, the components of which are contained in the gas sucked in by the pump.
  • By separating the liquid from the exhaust gas on the pressure side of the pump it is It is also possible, in particular via the overflow, to return condensed organic components of the exhaust gas, if necessary via an evaporative cooler, to the reactor for further conversion.
  • the pump which is also called a vacuum pump
  • a jet pump which is also called an ejector
  • the liquid comprises in particular an organic mixture and preferably consists of the organic mixture, and in particular the liquid contains 10 to 90% by weight of the at least one aromatic vinyl compound, in particular styrene and/or alpha-methylstyrene, 5 to 50% by weight of the at least one further monomer and 0.5 to 50% by weight of the organic solvent, in particular ethylbenzene, based on the total liquid in the vacuum system.
  • Styrene and/or alpha-methylstyrene is preferably added to the liquid.
  • the vacuum that can be achieved via the liquid ring pump system i.e. the minimum absolute pressure that can be achieved, is determined by the vapor pressure of the liquid used.
  • the presence of styrene and/or alpha-methylstyrene in the liquid can, for example, reduce the vapor pressure compared to acrylonitrile.
  • the at least one aromatic vinyl compound and the at least one further monomer are present in the at least one organic solvent in step a) and are polymerized in the at least one reactor, so that the polymerization product is formed.
  • a continuous bulk polymerization or solvent polymerization preferably takes place in the at least one reactor.
  • the polymerization product contains the copolymer, residual monomers, the at least one organic solvent and optionally oligomers. In order to separate volatile components from the polymerization product, this is fed to the degassing container via the first heat exchanger in which the polymerization product is heated.
  • the media inlet temperature refers to the temperature in the inlet of the heating or cooling medium of the respective heat exchanger.
  • the polymerization product is heated by a heating medium.
  • At least one further heat exchanger serves for cooling; a coolant is supplied to each of them.
  • the volatile components such as unreacted monomers, solvents or oligomers are preferably partially evaporated, so that the first heat exchanger can also be referred to as a partial evaporator.
  • the polymerization product is preferably present at a reactor temperature in a range from 105°C to 180°C, more preferably in a range from 105°C to 125°C or in a range from 140°C to 180°C.
  • the polymerization product is preferably heated in the first heat exchanger to a temperature in a range from 180°C to 270°C.
  • the first heat exchanger is preferably arranged on the degassing container and, in particular, forms a structural unit with the degassing container.
  • the first heat exchanger can be arranged separately from the degassing container.
  • the negative pressure is preferably present in the system, in particular the degassing container, into which the polymerization product including the volatile components from the first heat exchanger enters .
  • the copolymer is separated from the volatile components.
  • a phase containing the copolymer, which forms the lower phase in the degassing vessel, is removed.
  • a gaseous phase that contains the volatile components and is referred to as vapor or vapor stream is removed from the degassing container, in particular above the phase containing the copolymer.
  • the vapor stream is in particular gaseous.
  • the vapor stream preferably contains the aromatic vinyl compound, in particular aromatic vinyl monomer such as styrene and/or alpha-methylstyrene, the at least one further monomer, in particular vinyl cyanide monomer such as acrylonitrile, methacrylate monomer such as MMA, oligomers and/or organic solvent such as ethylbenzene , toluene and/or methyl ethyl ketone (MEK), and optionally water, in particular water vapor.
  • a solution which is fed to the first heat exchanger and from which the vapor stream is formed preferably contains 1 to 5,000 ppm of water.
  • the stream referred to in the invention as vapor stream B varies in terms of quantity and composition as the process steps described are carried out.
  • the copolymer produced preferably includes SAN copolymers, AMSAN copolymers and/or SMMA copolymers.
  • the vapor stream is preferably condensed in several stages. More preferably, the vapor stream is first condensed in a second heat exchanger and then in a third heat exchanger. The vapor stream is further cooled in the third heat exchanger, which also counteracts polymerization and thus blockage of the pipeline and, in particular, achieves condensation that is as complete as possible.
  • the liquid separator preferably has an overflow. Further preferably, liquid that passes through the overflow is removed from the vacuum system and in particular returned to the reactor.
  • the at least one aromatic vinyl compound A is fed to the liquid of the liquid ring pump system, in particular in a mixture with the inhibitor. Further preferably, at least parts of the at least one condensate are fed to the liquid F.
  • the liquid outlet of the second heat exchanger and/or the collecting space of the third heat exchanger are connected to the inlet space of the third heat exchanger via a first condensate line. If necessary, the liquid outlet of the second heat exchanger and / or the collecting space of the third heat exchanger are connected to the column head space of the column via a second condensate line. If necessary, the liquid outlet of the second heat exchanger and / or the collecting space of the third heat exchanger are connected to a vapor line that connects the degassing container to the column via a third condensate line.
  • the aromatic vinyl compound is preferably supplied at the liquid separator and/or between the liquid separator and the fourth heat exchanger.
  • the condensation efficiency can be slightly reduced compared to the addition of solvent to the vapor stream, according to EP 3 689 923 B1, and thus the amount of uncondensed vapor at the inlet of the vacuum system can be increased.
  • This is compensated for by using a liquid in the liquid ring pump system that contains at least one aromatic vinyl compound.
  • the uncondensed vapor can still be condensed in the vacuum system and returned to the reactor.
  • few monomers and/or solvents remain in the exhaust gas and correspondingly fewer organic components are condensed in the vacuum system.
  • the exchange rate of the liquid ring pump liquid is low, as is the amount of liquid flowing out via the overflow of the liquid separator. Due to the low exchange rate in the condensate with low overflow, the liquid has a relatively long residence time in the vacuum system, which can lead to polymerization and blockage. By additionally adding the aromatic vinyl compound A, the residence time of the liquid in the vacuum system is reduced, thus reducing polymerization.
  • the aromatic vinyl compound is a high boiler, so that a better vacuum, i.e. a lower absolute pressure, can be achieved when the aromatic vinyl compound is added to the liquid.
  • a lower residual monomer content in the degassed copolymer can be achieved through a lower pressure.
  • volatile components that were not condensed in the liquid can be condensed via an exhaust gas heat exchanger in the vacuum system and returned to the reactor.
  • the exhaust gas heat exchanger is preferably operated at a higher pressure than the second heat exchanger and/or the third heat exchanger.
  • the exhaust gas heat exchanger is operated at a pressure of more than 900 mbar. Therefore, the condensation efficiency of the exhaust gas heat exchanger is high, so that almost no gaseous vapors escape into the exhaust gas.
  • a portion of the at least one aromatic vinyl compound is added to the liquid, the at least one aromatic vinyl compound being present in a mixture with an inhibitor, and the amount of aromatic vinyl compounds added to the liquid is at least 10% by weight, more preferably at least 20% by weight.
  • the aromatic vinyl compound added preferably contains an inhibitor, in particular in a concentration of more than 1 ppm, based on the amount of aromatic vinyl compound added.
  • the content of inhibitor in particular, is preferably which are dissolved in the at least one aromatic vinyl compound, 1 to 50 ppm, based on the mixture of aromatic vinyl compound and inhibitor in the vacuum system.
  • the vapor stream is preferably cooled in at least a second heat exchanger and a third heat exchanger, the second heat exchanger having a second media inlet temperature T2 in a range from 10 ° C to 40 ° C, in particular from 15 ° C to 30 ° C, is operated and the third heat exchanger is operated with a third media inlet temperature T3 in a range from -10 ° to 30 ° C, in particular from -10 ° C to 15 ° C, and in particular the second media inlet temperature Temperature T2 is at least 10°C higher than the third media inlet temperature T3.
  • the amount of gaseous vapor that reaches the vacuum system can be controlled via the third media inlet temperature T3 on the third heat exchanger.
  • At least two heat exchangers are preferably used for condensing the vapor stream.
  • the third media inlet temperature is preferably lower than the second media inlet temperature. Accordingly, the heat exchanger is preferably operated at a higher temperature than the heat exchanger.
  • the third heat exchanger connected downstream which is preferably operated with a lower coolant temperature than the second heat exchanger connected upstream of it, only the volatile components still remaining in the vapor after the second heat exchanger are condensed.
  • the coolant with a lower temperature in the third heat exchanger is only required for some of the volatile components. For the condensation of the part of the volatile components that has already been condensed in the second heat exchanger, a coolant with a higher temperature is sufficient, which is energetically advantageous.
  • the condensation effect can be improved, so that the proportion of vapors that can already be condensed in the second heat exchanger is increased.
  • the liquid is cooled in a pump heat exchanger, which can also be referred to as a fourth heat exchanger.
  • a pump heat exchanger which can also be referred to as a fourth heat exchanger.
  • the portion of the at least one aromatic vinyl compound is added to the liquid before the pump heat exchanger.
  • the pump heat exchanger is preferably operated with a fourth media inlet temperature T4. More preferably, the fourth media inlet temperature T4 is lower than the second media inlet temperature T2 of the second heat exchanger. In particular, a difference between the second media inlet temperature T2 and the fourth media inlet temperature T4 is at least 10°C.
  • the exhaust gas from the vacuum system is at least partially condensed in the exhaust gas heat exchanger, which is also referred to as the fifth heat exchanger, more preferably at ambient pressure, in particular at a pressure of more than 900 mbar.
  • the exhaust gas heat exchanger is operated with a fifth media inlet temperature T5, more preferably the fifth media inlet temperature T5 is lower than the second media inlet temperature T2 of the second heat exchanger.
  • a difference between the second media inlet temperature T2 and the fifth media inlet temperature T5 is at least 10°C. Due to the lower temperature at the exhaust gas heat exchanger, components that have left the second heat exchanger in a gaseous state can still be condensed downstream of the second heat exchanger. In the second heat exchanger, not all components necessarily have to be condensed, so that the second heat exchanger can be operated with a warmer coolant such as river water.
  • the vacuum system has in particular a liquid ring pump liquid circuit with the liquid separator and the overflow.
  • the vacuum system preferably comprises the liquid ring pump system, a jet pump, the liquid ring pump liquid circuit with the liquid separator and the overflow, the fourth heat exchanger and the exhaust gas heat exchanger.
  • the vapor stream in particular upstream of the at least one further heat exchanger, in particular upstream of the second heat exchanger and the third heat exchanger, is passed through a separation unit, in particular a column, in which the vapor stream is mixed with the at least one condensate, in particular with the first condensate and/or the second condensate, is brought into contact, wherein oligomers are removed from the vapor stream, and the at least one condensate, preferably the first condensate and / or the second condensate, is fed in particular at the top of the column.
  • the second heat exchanger is preceded by a column which can have internals. The first condensate and/or the second condensate are preferably fed to the column in the upper part, in particular at the top.
  • the bottom of the column is preferably heated, in particular to a temperature in a range from 150°C to 280°C. Oligomers which have been condensed out of the vapor stream are preferably collected in the bottom.
  • the remaining vapor stream is preferably removed at the top of the column and fed to the at least one further heat exchanger, in particular the second heat exchanger.
  • a liquid phase from the bottom of the column can be recycled, in particular for further depletion of monomers and solvent, and in particular together with the at least one condensate, in particular with the first condensate and/or the second condensate, fed upstream of the column, in particular at a first point.
  • first element such as a heat exchanger or a column
  • second element such as another heat exchanger
  • a first condensate is formed in the second heat exchanger, while the remaining gaseous vapor stream is fed into the third heat exchanger, where a second condensate is formed.
  • the first condensate and/or the second condensate are preferably fed back at least into the third heat exchanger and additionally or alternatively, in particular additionally, further upstream of the second heat exchanger, and brought into contact with the vapor stream.
  • the at least one condensate in particular the first condensate and/or the second condensate, are returned, in particular injected, into the column and/or into a vapor line between the degassing container and the column.
  • the vacuum system is preferably arranged downstream of a last one of the at least one further heat exchanger, in particular the third heat exchanger.
  • the vacuum system supplies the negative pressure in particular in the first heat exchanger, the degassing container, possibly the column, the at least one further heat exchanger, in particular the second heat exchanger and the third heat exchanger.
  • the first condensate and/or the second condensate are preferably returned to the vapor stream B.
  • a first condensate emerges from the second heat exchanger and a second condensate emerges from the third heat exchanger. Further preferably, the first condensate and/or the second condensate are returned and brought into contact with the vapor stream B at at least one point upstream of the second heat exchanger and/or at another point in the third heat exchanger, in particular injected into the vapor stream.
  • the condensation of the vapor stream i.e. the volatile components from the polymerization product
  • the condensation of the vapor stream can be carried out more effectively and with lower emissions.
  • the oligomers obtained with the condensation have a higher purity.
  • the volatile components are cooled before the actual condensation is carried out, so that the cooling output still to be provided by the heat exchangers is reduced and at the same time the condensation efficiency is increased.
  • the first condensate and/or the second condensate are brought into direct contact with the vapor stream at a first point upstream of the column, in particular injected into a vapor line. Additionally or alternatively, the first condensate and/or the second condensate are brought into direct contact with the vapor stream at a second point in the column. Additionally or alternatively, the first condensate and/or the second condensate are brought into direct contact with the vapor stream at a third point in the third heat exchanger.
  • the vapor stream is cooled before entering the column, so that fewer deposits, i.e. a lower degree of polymerization, occur in the column.
  • the addition of the first condensate and/or the second condensate at the second location leads to further separation of oligomers from the condensate.
  • the return of the first condensate and/or the second condensate at the third point serves in particular to cool condensate from the first buffer container.
  • the third heat exchanger is preferably arranged vertically; more preferably, the first condensate and/or the second condensate are supplied in an inlet space of the third heat exchanger.
  • the vapor stream is preferably cooled by supplying the first condensate and/or the second condensate at the first point, the temperature difference in the vapor stream before and after the first point being at least 25 ° C and the vapor stream after the first point having a temperature of at least 120 °C.
  • the vapor stream is preferably cooled by supplying the first condensate and/or the second condensate at the second point, the vapor stream further preferably having a temperature in a range from 65 ° C to 190 ° C after the first point.
  • At least one buffer tank can be arranged, which can also be referred to as a storage tank.
  • the at least one condensate in particular the first condensate and/or the second condensate, is collected in one or more buffer tanks, with water, in particular from the at least one condensate, being separated in at least one buffer tank if necessary.
  • At least one of the one or more buffer tanks preferably comprises a water separator.
  • the vapor stream When removed from the degassing container, the vapor stream preferably contains 10 to 90% by weight, in particular 25 to 65% by weight, of at least one aromatic vinyl compound, in particular styrene and/or alpha-methylstyrene, in 5 to 60% by weight. , in particular 10 to 40% by weight, the at least one further monomer, in particular acrylonitrile, and 0.5 to 50% by weight, in particular 25 to 45% by weight, of the organic solvent, in particular ethylbenzene, toluene and / or MEK, each based on the total vapor flow.
  • the organic solvent in particular ethylbenzene, toluene and / or MEK
  • an inhibitor can be added upstream of the vacuum system.
  • an inhibitor is added to the first condensate and/or the second condensate, in particular upstream of the third heat exchanger.
  • the inhibitor is preferably fed to the third heat exchanger together with the first condensate and/or the second condensate.
  • the inhibitor in particular dissolved in the at least one aromatic vinyl compound, is added in an amount of 1 to 20 ppm, based on the vapor stream that is removed from the degassing vessel.
  • the inhibitor preferably contains or consists of 4-tert-butylcatechol (TBC), alkoxyphenol such as 4-methoxyphenol (MEHQ) and/or, in particular sterically hindered, thiophenol such as 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxyl (4-hydroxy-TEMPO).
  • TBC 4-tert-butylcatechol
  • MEHQ 4-methoxyphenol
  • thiophenol such as 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxyl (4-hydroxy-TEMPO).
  • the sum of the amounts of the at least one condensate, in particular the first condensate and the second condensate, which is returned at the at least one location and the further location, in particular at the first location, the second location and the third location, is at least 50% by weight, based on the vapor stream which is removed from the degassing vessel.
  • the at least one condensate in particular the first condensate and/or the second condensate, is fed to the first location in a total amount of up to 40% by weight, based on the vapor stream that is removed from the degassing vessel.
  • the at least one condensate, in particular the first condensate and/or the second condensate is preferably fed to the column, in particular at the second location, in a total amount of up to 150% by weight, based on the vapor stream that is removed from the degassing vessel. If more than 100% by weight is returned, the condensate is recirculated multiple times.
  • the at least one condensate in particular the first condensate and/or the second condensate, is injected into the vapor line upstream of the column, in particular at the at least one point.
  • the first heat exchanger and the at least one further heat exchanger are preferably designed as tube bundle heat exchangers.
  • the first heat exchanger is preferably arranged vertically.
  • the second heat exchanger is preferably arranged horizontally.
  • the third heat exchanger is preferably arranged vertically.
  • a vertical arrangement is understood to mean that in the direction of gravity there is first an inlet space, in particular a head space, then a heat exchange surface, in particular a tube bundle, and then a collecting space, in particular a swamp space.
  • the inlet space is preferably a head space and the collecting space is preferably a bottom space.
  • tubes of the first heat exchanger and/or the third heat exchanger are aligned in the direction of gravity.
  • the tubes, in particular of the second heat exchanger are arranged perpendicular to the direction of gravity.
  • the at least one condensate in particular the first condensate and/or the second condensate, are preferably injected into the head space of the third heat exchanger, in particular in the flow direction of the vapor stream.
  • Water is preferably used as the medium in the second heat exchanger.
  • Brine and/or water containing glycol is preferably used as the medium in the third heat exchanger.
  • the medium in the second heat exchanger and in the third heat exchanger is preferably a cooling medium.
  • the second heat exchanger is preferably operated with river water or a coolant that is provided by cooling with river water.
  • the river water is preferably used in a secondary circuit.
  • the medium in the first heat exchanger is in particular a heating medium.
  • Diphyl steam such as Therminol VP1 or a heating fluid, in particular a heating oil, is preferably used as the medium in the first heat exchanger.
  • the heating oil is preferably selected from mineral oils or synthetic oils, which are known to the person skilled in the art, for example as Therminol T66, T62, T55, T72 or Melatherm SH.
  • Figure 1 is a schematic representation of a process overview
  • Figure 2 is a schematic representation of an embodiment of the method according to the invention.
  • FIG. 1 shows a schematic representation of a process overview.
  • An aromatic vinyl compound A, at least one further monomer M and an organic solvent L are fed to a reactor R.
  • a polymerization product PP is formed which comprises a copolymer CP and the organic solvent L.
  • the polymerization product PP is first fed to a first heat exchanger WT1, where the polymerization product PP is heated with a heating medium that has a first media inlet temperature T1.
  • the heated polymerization product PP passes from the first heat exchanger WT1 into a degassing vessel EB, from which the copolymer CP and a gaseous vapor stream B containing volatile components are removed.
  • the vapor stream B is led from the degassing vessel EB via a vapor line BL into a column K with a column headspace KKR, which has internals E. Oligomers OL are removed from the bottom of the column K, which is heated with a heating jacket H. From the top of the column K, the remaining vapor stream B is transferred further into a second heat exchanger WT2, where the vapor stream B is partially condensed with a coolant that has a second media inlet temperature T2, so that a first condensate KS1 is removed from the second heat exchanger WT2 at a liquid outlet FLA.
  • the first condensate KS1 is temporarily stored in a first buffer tank PB1.
  • the remaining gaseous vapor stream B passes from the second heat exchanger WT2 from a gas outlet GA into a third heat exchanger WT3, where it is further condensed by means of a further coolant with a third media inlet temperature T3.
  • the second heat exchanger WT2 is arranged horizontally, while the third heat exchanger WT3 is arranged vertically.
  • a second condensate KS2 is taken from the third heat exchanger WT3 from a sump space SR and fed to a second buffer container PB2. Water W is separated in the second buffer container PB2.
  • the second buffer container PB2 is filled hydraulically, an upper phase flows over the top of the second buffer container PB2 into a third buffer container PB3.
  • a vacuum system VA is also connected to the sump space SR of the third heat exchanger WT3, which is operated with a liquid F and includes a vacuum pump VP and a liquid separator FA with an overflow U.
  • the vacuum pump VP is designed as a liquid ring pump.
  • the liquid F is cooled in a fourth heat exchanger WT4.
  • An exhaust gas AG from the vacuum system VA is condensed in a fifth heat exchanger WT5 in order to reduce gaseous emissions from the process.
  • Buffer is stored in the third buffer container PB3 to compensate for fluctuations in throughput.
  • the first condensate KS1 from the heat exchanger WT2 is injected into the vapor stream B at a first point ED1 in the vapor line BL in front of the column K. By evaporating the first condensate KS1 at the first point ED1, the vapor stream B is already cooled before it enters the column K.
  • the first condensate KS1 from the second heat exchanger WT2 is introduced into the top of the column K at a second point ED2 and brought into contact with the vapor stream B in order to separate the oligomers OL.
  • the first condensate KS1 is injected at a third location ED3 in a headspace KR of the third heat exchanger WT3 in order to further cool the vapor stream B and obtain the second condensate KS2.
  • the second condensate KS2 and the mixture from the third buffer container PB3 can be partially added to the first condensate KS1 for return to the first point ED1, the second point ED2 or the third point ED3.
  • the mixture collected in the third buffer container PB3 is returned to the reactor R by a pump and, if necessary, by a further buffer container in order to convert remaining unreacted monomers into the copolymer CP.
  • Pumps P are used to convey the condensates KS1, KS2.
  • Figure 2 shows a schematic representation of an embodiment of the method according to the invention.
  • the aromatic vinyl compound A and the further monomer M are converted in the reactor R in the solvent L to form the copolymer CP.
  • the polymerization product PP is transferred to the degassing vessel EB, which has a first heat exchanger WT1, in which the copolymer CP is separated from a vapor stream B.
  • the vapor stream B is subjected to multi-stage condensation using a second heat exchanger WT2 and a third heat exchanger WT3.
  • a first condensate KS1 and a second condensate KS2 are formed, which are temporarily stored in a buffer container PB and at least partially returned to the reactor R.
  • the remaining gaseous vapor stream B from the condensation enters a vacuum system VA, which includes a liquid ring pump system.
  • the vacuum system VA is followed by a liquid separator FA, in which a liquid F is separated, with which the liquid ring pump system is operated.
  • the liquid F which is separated by means of the liquid separator FA, is added aromatic vinyl compound A in a mixture with inhibitor via a supply line ZL and the liquid stream is fed to a fourth heat exchanger WT4 before the liquid F and the added aromatic vinyl compound A are returned to the vacuum system VA.
  • An exhaust gas AG from the liquid separator FA is further cooled in an exhaust gas heat exchanger WT5 in order to remove condensable components from the exhaust gas AG.
  • the fourth heat exchanger WT4 is operated with a fourth media inlet temperature T4 and the exhaust gas heat exchanger WT5 is operated with a fifth media inlet temperature T5.
  • a total feed stream of 10.9 t/h was fed to the reactor. 6.9 t/h of copolymer and 4 t/h of vapor were removed from the degassing vessel.
  • the polymer contained 65% by weight of styrene and 35% by weight of ACN.
  • a pressure of 50 mbar absolute was measured in the degassing vessel.
  • the vapor stream was removed from the degassing vessel at a temperature of 260°C. Upstream of the column, the vapor stream was brought into contact with 325 l/h of the first condensate. The bottom of column K was heated to 250 °C. 2.2 t/h of the first condensate were fed to the top of the column.
  • a pressure of 45 mbar was present at the top of the column.
  • the vapor stream was taken from the top of the column at a temperature of 160 °C and fed to the second heat exchanger, where it was partially condensed with a coolant with a second media inlet temperature T2 of 23 °C.
  • the second media temperature was 30 °C when leaving the second heat exchanger.
  • 3.5 t/h of the first condensate were taken from the second heat exchanger and the remaining vapor stream was fed to the third heat exchanger at a temperature of 30 °C.
  • the first condensate had a temperature of 47 °C.
  • 1.0 t/h of the first condensate was sprayed into the head space of the third heat exchanger.
  • the third media inlet temperature T3 at the third heat exchanger was 7 °C.
  • a quantity of 150 kg/h of gaseous vapor was supplied to the liquid ring pump when the negative pressure was generated.
  • the fourth heat exchanger WT4 was 0.5 t/h of a solution containing 12 ppm TBC in styrene was added.
  • the fourth heat exchanger WT4 and the exhaust gas heat exchanger WT5 were operated with a coolant inlet temperature, T4 and T5, of 7 ° C.
  • the amount removed from the overflow was 650 kg/h. Only traces of monomers or solvents were detectable in the exhaust gas from the WT5 exhaust gas heat exchanger. There was no wastewater to be disposed of.
  • Example 2 was essentially carried out in the same way as Example 1, but the styrene supply was shut off before the fourth heat exchanger WT4. As a result, a slow increase in the pressure in the degassing tank to 55 mbar absolute was observed. After about 6 months of operation, growths were found at the outlet of the liquid ring pump and in the line from the liquid separator to the third buffer tank PB3.

Abstract

L'invention concerne un procédé de préparation d'un copolymère (CP) à partir d'au moins un composé vinylique aromatique (A), en particulier du styrène et/ou de l'alpha-méthylstyrène, et d'au moins un autre monomère (M) du groupe constitué par l'acrylonitrile et le méthacrylate, le procédé comprenant les étapes suivantes : a) polymérisation, b) élimination de composants volatils pour obtenir un courant de vapeur (B), c) condensation d'au moins des parties du courant de vapeur (B), une pression négative étant créée au moyen d'un système à vide (VA) et le système à vide (VA) comprenant au moins une pompe (P) qui est conçue sous la forme d'un système de pompe à anneau liquide et qui est actionnée avec un liquide (F), qui sur le côté pression de la pompe (P) est séparé au moyen d'un séparateur de liquide (FA) d'un gaz de décharge prélevé de la pompe (P) et est fourni à la pompe (P). L'invention concerne également un appareil permettant la mise en œuvre du processus.
PCT/EP2023/076791 2022-09-29 2023-09-27 Procédé de préparation d'un copolymère à partir d'au moins un composé vinylique aromatique WO2024068783A1 (fr)

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EP22198793 2022-09-29
EP22198793.6 2022-09-29

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4181788A (en) * 1977-05-28 1980-01-01 Bayer Aktiengesellschaft Process for the production of thermoplastic molding materials based on vinyl polymers
US4555384A (en) 1982-09-24 1985-11-26 Cosden Technology, Inc. Apparatus for producing styrenic/alkenylnitrile copolymers
WO2001074925A1 (fr) * 2000-03-30 2001-10-11 Bayer Aktiengesellschaft Composition de polyamide et son procede de production
WO2011087728A2 (fr) * 2010-01-14 2011-07-21 Exxonmobil Chemical Patents Inc. Procédés et appareils pour réaliser une polymérisation en solution en continu
EP3689919A1 (fr) 2018-12-19 2020-08-05 LG Chem, Ltd. Procédé et appareil pour la production d'un copolymère composé vinylique aromatique-composé cyan vinylique
EP3689923B1 (fr) 2018-12-18 2021-05-12 LG Chem, Ltd. Procédé et dispositif de préparation d'un polymère de composé aromatique de vinyle-composé de cyanure de vinyle

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4181788A (en) * 1977-05-28 1980-01-01 Bayer Aktiengesellschaft Process for the production of thermoplastic molding materials based on vinyl polymers
US4555384A (en) 1982-09-24 1985-11-26 Cosden Technology, Inc. Apparatus for producing styrenic/alkenylnitrile copolymers
WO2001074925A1 (fr) * 2000-03-30 2001-10-11 Bayer Aktiengesellschaft Composition de polyamide et son procede de production
WO2011087728A2 (fr) * 2010-01-14 2011-07-21 Exxonmobil Chemical Patents Inc. Procédés et appareils pour réaliser une polymérisation en solution en continu
EP3689923B1 (fr) 2018-12-18 2021-05-12 LG Chem, Ltd. Procédé et dispositif de préparation d'un polymère de composé aromatique de vinyle-composé de cyanure de vinyle
EP3689919A1 (fr) 2018-12-19 2020-08-05 LG Chem, Ltd. Procédé et appareil pour la production d'un copolymère composé vinylique aromatique-composé cyan vinylique

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