WO2016199040A1 - Procédé pour la production de styrène à partir de xylène par déshydrogénation d'éthyl benzène - Google Patents

Procédé pour la production de styrène à partir de xylène par déshydrogénation d'éthyl benzène Download PDF

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Publication number
WO2016199040A1
WO2016199040A1 PCT/IB2016/053372 IB2016053372W WO2016199040A1 WO 2016199040 A1 WO2016199040 A1 WO 2016199040A1 IB 2016053372 W IB2016053372 W IB 2016053372W WO 2016199040 A1 WO2016199040 A1 WO 2016199040A1
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Prior art keywords
styrene
distillation column
xylene
divided wall
ethyl benzene
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PCT/IB2016/053372
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English (en)
Inventor
Debasish Das
Pankaj MATHURE
Onen Amiruddin Attarwala
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Sabic Global Technologies B.V.
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Publication of WO2016199040A1 publication Critical patent/WO2016199040A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
    • C07C5/32—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with formation of free hydrogen
    • C07C5/327—Formation of non-aromatic carbon-to-carbon double bonds only
    • C07C5/333—Catalytic processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/009—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping in combination with chemical reactions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/14—Fractional distillation or use of a fractionation or rectification column
    • B01D3/143—Fractional distillation or use of a fractionation or rectification column by two or more of a fractionation, separation or rectification step
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/04—Purification; Separation; Use of additives by distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
    • C07C2523/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper
    • C07C2523/74—Iron group metals
    • C07C2523/745—Iron
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
    • C07C2523/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper
    • C07C2523/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups C07C2523/02 - C07C2523/36
    • C07C2523/78—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups C07C2523/02 - C07C2523/36 with alkali- or alkaline earth metals or beryllium
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
    • C07C2523/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper
    • C07C2523/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups C07C2523/02 - C07C2523/36
    • C07C2523/84—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups C07C2523/02 - C07C2523/36 with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency

Definitions

  • a basic styrene production process can include a process wherein a mixture of ethyl benzene and xylene contacts a dehydrogenating catalyst under operating conditions adequate to produce a conversion of the ethyl benzene contained therein to styrene.
  • Another process describes the immediate cooling of the final dehydrogenation effluent at temperatures of about 680°C to about 200°C by use of an economizer or waste heat boiler which employs purified water produced in the system and generates economizer steam for admixture with initial charging stock.
  • Latent heat can be employed in the reactor effluent to heat a single ethyl benzene vacuum column re-boiler. The heat is transferred from the reactor effluent by either introducing it directly into the re-boilers or by using it to form steam which is thereafter introduced into the re-boilers.
  • a process for producing styrene comprises: contacting a feed mixture comprising ethyl benzene and xylene with a dehydrogenation catalyst in a dehydrogenation reactor to form a reaction mixture comprising styrene, xylene, ethyl benzene, or a combination comprising at least one of the foregoing under operating conditions to produce a greater than or equal to 70% conversion of the ethyl benzene to styrene; and passing the reaction mixture through a divided wall distillation column to separate the styrene from the other components of the reaction mixture, wherein styrene is removed as a first product from the divided wall distillation column at a bottom portion of the divided wall distillation column and the other components of the reaction mixture are removed as a second product at a top portion of the divided wall distillation column.
  • a process for producing polystyrene comprises: contacting a feed mixture comprising ethyl benzene and xylene with a dehydrogenation catalyst in a dehydrogenation reactor to form a reaction mixture comprising styrene, xylene, ethyl benzene, or a combination comprising at least one of the foregoing under operating conditions to produce a greater than or equal to 70% conversion of the ethyl benzene to styrene; passing the reaction mixture through a divided wall distillation column; separating the reaction mixture into fractions in the divided wall distillation column, wherein the fractions comprise styrene, xylene, and unconverted ethyl benzene; distributing the xylene and unconverted ethyl benzene fractions to a top portion of the divided wall distillation column; distributing the styrene to a bottom portion of the divided wall distillation column; condensing the
  • FIG. 1 is a flow diagram representing a general overview of one embodiment of the styrene production process disclosed herein.
  • the use of a divided wall distillation column can reduce the number of components needed for conversion of raw materials to styrene and can also allow for efficient separation and removal of the components of the process, e.g., water, unconverted xylenes, and styrene.
  • the process disclosed herein provides for the conversion of the generally low value ethyl benzene fraction to styrene and allows for the removal of any unconverted ethyl benzene more efficiently than other processes.
  • a process for producing styrene can include contacting a feed mixture with a dehydrogenation catalyst in a dehydrogenation reactor to form a reaction mixture.
  • the feed mixture can include ethyl benzene and xylene and the reaction mixture can include styrene, xylene, ethylene benzene, or a combination comprising at least one of the foregoing.
  • the operating conditions in the dehydrogenation reactor can produce a greater than or equal to 70% conversion of ethyl benzene to styrene, for example, the operating conditions in the dehydrogenation reactor can produce a greater than or equal to 75% conversion of ethyl benzene at a reaction temperature of 600°C.
  • the process can further include passing the reaction mixture through a divided wall distillation column to separate the styrene from the other components of reaction mixture such that styrene can be removed as a first product at a bottom portion of the divided wall distillation column and the other components of the reaction mixture, e.g., styrene, xylene, and ethyl benzene, can be removed as a second product at a top portion of the divided wall distillation column.
  • a divided wall distillation column to separate the styrene from the other components of reaction mixture such that styrene can be removed as a first product at a bottom portion of the divided wall distillation column and the other components of the reaction mixture, e.g., styrene, xylene, and ethyl benzene, can be removed as a second product at a top portion of the divided wall distillation column.
  • a process for producing styrene can include contacting a feed contacting a feed mixture with a dehydrogenation catalyst in a dehydrogenation reactor to form a reaction mixture.
  • the feed mixture can include ethyl benzene and xylene and the reaction mixture can include styrene, xylene, ethylene benzene, or a combination comprising at least one of the foregoing.
  • the feed mixture can include a hydrocarbon mixture, e.g., ethyl benzene and xylene.
  • the hydrocarbon mixture can comprise aromatic hydrocarbons such as ethyl benzene, toluene, mesitylene, benzene, or a combination comprising at least one of the foregoing, as well as xylene isomers having the general chemical formula CSHJO (C8) such as ortho-xylene (o-xylene), meta-xylene (m-xylene), paraxylene (p-xylene), xylol, or a combination comprising at least one of the foregoing.
  • aromatic hydrocarbons such as ethyl benzene, toluene, mesitylene, benzene, or a combination comprising at least one of the foregoing
  • xylene isomers having the general chemical formula CSHJO (C8) such as ortho-xylene (o-xylene), meta-xylene (m-xylene), paraxylene (p-xylene), xylol, or a combination comprising at least one
  • Feed mixture can also include other forms of hydrocarbons such as cycloalkanes, alkyne based compounds, unsaturated hydrocarbons, olefins, saturated hydrocarbons, paraffins, alkanes, alkenes, or a combination comprising at least one of the foregoing.
  • hydrocarbons such as cycloalkanes, alkyne based compounds, unsaturated hydrocarbons, olefins, saturated hydrocarbons, paraffins, alkanes, alkenes, or a combination comprising at least one of the foregoing.
  • dehydrogenation reactor can produce a greater than or equal to 70% conversion of ethyl benzene to styrene.
  • the reaction conditions can be such that only ethyl benzene reacts to give styrene, benzene, and toluene.
  • Selectivity toward styrene can be greater than or equal to 85%, for example, greater than or equal to 90%, for example, greater than or equal to 92%, for example, greater than or equal to 93%.
  • the selectivity toward styrene can be 85% to 95%, for example, 90% to 93%.
  • Selectivity toward benzene and toluene can together be greater than or equal to 5%, for example, greater than or equal to 7% , for example, greater than or equal to 10%, for example, greater than or equal to 15%.
  • the selectivity toward benzene and toluene can be 5% to 15%, for example, 6% to 12%, for example, 7% to 10%.
  • the process can further include passing the reaction mixture through a divided wall distillation column and separating the reaction mixture into fractions in the divided wall distillation column, the fractions can include styrene, xylene, and unconverted ethyl benzene.
  • the process can include distributing the xylene and unconverted ethyl benzene fractions to a top portion of the divided wall distillation column, distributing the styrene to a bottom portion of the divided wall distillation column, condensing the xylene and unconverted ethyl benzene exiting the top portion of the divided wall distillation column, vaporizing the styrene exiting the bottom portion of the divided wall distillation column; and withdrawing the styrene fraction from the bottom portion of divided wall distillation column.
  • the divided wall distillation column can be operated at a pressure of 1 kiloPascal (kPa) to 500 kPa and a temperature of 120°C in the bottom portion.
  • the pressure can be 2.5 kPa to 100 kPa, for example, 5 kPa to 50 kPa, for example, 6.5 kPa to 40 kPa, for example, 10 kPa to 25 kPa.
  • the temperature can be greater than or equal to 75°C, for example, greater than or equal to 100°C, for example, greater than or equal to 120°C, for example, greater than or equal to 150°C.
  • the source of the feed mixture can include a catalytic reforming process, a steam cracking process, a gasoline separation process, an olefin separation process, a clay tower distillation process, or a combination comprising at least one of the foregoing.
  • the feed mixture can include 10 weight percent (wt. %) to 80 wt. % ethyl benzene, for example, 15 wt. % to 75 wt. %, for example, 20 wt. % to 65 wt. %, for example, 30 wt. % to 50 wt . %.
  • the dehydrogenation catalyst can include a combination for materials, for example, the dehydrogenation catalyst can include metal oxides such as including, but not limited to, ferric oxide, potassium oxide, chromium oxide, cerium oxide, molybdenum oxide, titanium oxide, calcium oxide, magnesium oxide, or a combination comprising at least one of the foregoing.
  • the ferric oxide can be present in an amount of 65 wt. % to 95 wt. %, for example, 85 wt. % to 90 wt. %
  • potassium oxide can be present in an amount of 5 wt. % to 20 wt. %, for example, 8 wt. % to 10 wt. %.
  • the dehydrogenation catalyst can be added to the reaction mixture as a promoter in the presence of steam, where a ratio of steam to organic material is 1:1 to 2:1, for example, 1:1 to 1.25:1.
  • the temperature within the temperature within the dehydrogenation catalyst can include metal oxides such as including, but not limited to
  • dehydrogenation reactor can be 500°C to 1,000°C, for example, 525°C to 800°C, for example, 540°C to 750°C.
  • the pressure within the dehydrogenation reactor can be -100 kPa to 200 kPa, for example, -75 kPa to 150 kPa, for example, -40 kPa to 105, kPa, for example, - 25 kPa to 75 kPa.
  • the reaction e.g., dehydrogenation reaction
  • the reaction in the dehydrogenation reactor can produce greater than or equal to 70% conversion of ethyl benzene, for example, greater than or equal to 80%, for example, greater than or equal to 90%.
  • the selectivity to styrene can be 75% to 99%, for example, 90% to 95%.
  • Water can be supplied simultaneously with the feed stream and can function as a diluent and a heat source. Any hydrogen produced by the reaction in the dehydrogenation reactor can be used as a source of hydrogen for an upstream hydrogenation process, fuel for an upstream process, or a combination comprising at least one of the foregoing.
  • the process can further include passing the reaction mixture through a heat recovery unit and cooling the reaction mixture to a temperature of less than or equal to 200°C, for example, less than or equal to 175°C, for example, less than or equal to 160°C, for example, less than or equal to 125°C before entry to the divided wall distillation column.
  • the heat recovery unit can include a shell and/or heat tube exchanger. Styrene can be separated from the mixture using distillation, for example, by using the divided wall distillation column as disclosed herein. Styrene can be removed from a bottom portion of the divided wall distillation column and water and other unconverted C8 components can be removed from a top portion of the divided wall distillation column.
  • an inhibitor Before entering the divided wall distillation column, an inhibitor can be added to the reactor more, for example, 4-tert butyl catechol (TBC), phenolic inhibitors such as 4-TBC, hydroquinone, or a combination comprising at least one of the foregoing.
  • Phenol compounds e.g., nitrated phenol compound can be used as an inhibitor as a polymerization retarder, alone or in combination with any of the previously listed inhibitors.
  • the inhibitor can prevent styrene polymerization during the distillation process in the divided wall distillation column. Subsequently, after removal from the divided wall distillation column the styrene can be processed to produce polystyrene.
  • the process can further include passing the unconverted materials through a separation unit, e.g., a xylene splitter, wherein unconverted ethyl benzene, /?-xylene, o- xylene, m-xylene, or a combination comprising at least one of the foregoing is isolated in the xylene splitter.
  • a separation unit e.g., a xylene splitter
  • a first product comprising unconverted ethyl benzene, /?-xylene, and m- xylene can then be withdrawn from a top portion of the xylene splitter and a second product comprising o-xylene can be withdrawn from a bottom portion of the xylene splitter.
  • Unconverted materials can be recycled from the xylene splitter to the dehydrogenation reactor.
  • the first product can be recycled to the dehydrogenation reactor.
  • FIG. A more complete understanding of the components, processes, and apparatuses disclosed herein can be obtained by reference to the accompanying drawings.
  • FIG. These figures (also referred to herein as "FIG.") are merely schematic representations based on convenience and the ease of demonstrating the present disclosure, and are, therefore, not intended to indicate relative size and dimensions of the devices or components thereof and/or to define or limit the scope of the exemplary embodiments.
  • specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to the particular structure of the embodiments selected for illustration in the drawings, and are not intended to define or limit the scope of the disclosure.
  • FIG. In the drawings and the following description below, it is to be understood that like numeric designations refer to components of like function.
  • stream 1 serves as a feed stream for unit 10.
  • Stream 1 can be continuously and constantly supplied to unit 10.
  • Water can be supplied and fed alongside stream 1 to unit 10.
  • the water can act as a diluting agent to aid in the flow of a viscous feed stream.
  • the water can also serve as a heat source to influence the temperature of the feed stream.
  • the composition of stream 1 can include a hydrocarbon mixture.
  • the hydrocarbon mixture can comprise ethyl benzene and xylene.
  • the hydrocarbon mixture can comprise aromatic hydrocarbons such as ethyl benzene, toluene, mesitylene, benzene, or a combination comprising at least one of the foregoing, as well as xylene isomers having the general chemical formula CsHio such as ortho-xylene (o-xylene), meta-xylene (m-xylene), paraxylene (p-xylene), xylol, or a combination comprising at least one of the foregoing.
  • aromatic hydrocarbons such as ethyl benzene, toluene, mesitylene, benzene, or a combination comprising at least one of the foregoing
  • xylene isomers having the general chemical formula CsHio such as ortho-xylene (o-xylene), meta-xylene (m-xylene), paraxylene (p-xylene), xylol, or a combination comprising at least one of the fore
  • Stream 1 can also include other forms of hydrocarbons such as cycloalkanes, alkyne based compounds, unsaturated hydrocarbons, olefins, saturated hydrocarbons, paraffins, alkanes, alkenes, or a combination comprising at least one of the foregoing.
  • the composition of stream 1 can comprise 20 weight % (wt. %) to 65 wt. % ethyl benzene depending on the source of origin.
  • the source of stream 1 can be any process related to the petrochemical industry.
  • the process can include catalytic reforming processes used to convert petroleum refinery naphtha distilled from crude oil into high-octane liquid reformate products and high-octane gasoline.
  • Stream 1 can also originate from processes for converting low- octane linear hydrocarbons into branched alkanes and cyclic naphthenes that are partially dehydrogenated to produce high-octane aromatic hydrocarbons.
  • the source of stream 1 can optionally include a steam cracking process that produces pyrolysis gasoline.
  • the process can include any process for breaking down saturated hydrocarbons into smaller unsaturated hydrocarbons to produce lighter alkenes, including ethylene and propylene.
  • the source of stream 1 can include any product of steam cracking facilities in which a feedstock such as naphtha, liquefied petroleum gas, ethane, propane, or butane is thermally cracked through the use of steam in a bank of pyrolysis furnaces to produce lighter hydrocarbons.
  • the source of stream 1 can include the fluid catalytic cracking conversion processes widely used in petroleum refineries wherein high-boiling, high-molecular weight hydrocarbon fractions of petroleum crude oils are converted to more valuable gasoline, olefin gases, and other products.
  • Stream 1 can originate from any combination of the processes previously disclosed herein including those involving clay packed distillation columns.
  • stream 1 can be fed to the unit 10, e.g., the unit 10,
  • unit 10 can be a catalytic dehydrogenation reactor operated to convert ethyl benzene to styrene.
  • Catalytic reactors used for the dehydrogenation of aromatics can include continuous catalytic reactors such as tubular reactors, fixed bed reactors, fluid bed reactors, and continuous stirred tank reactors.
  • Any ethyl benzene dehydrogenation catalyst can be employed in unit 10.
  • the catalyst include a combination for materials
  • the dehydrogenation catalyst can include metal oxides such as including, but not limited to, ferric oxide, potassium oxide, chromium oxide, cerium oxide, molybdenum oxide, titanium oxide, calcium oxide, magnesium oxide, or a combination comprising at least one of the foregoing.
  • the dehydrogenation catalyst can comprise 85 wt. % to 90 wt. % ferric oxide and can further include one or more metal oxides acting as catalytic reaction promoters.
  • the catalyst can comprise any metal oxide promoter, including, but not limited to potassium oxide, chromium oxide, cerium oxide, molybdenum oxide, titanium oxide, calcium oxide, magnesium oxide, or a combination comprising at least one of the foregoing.
  • the ferric oxide can be present in an amount of 65 wt. % to 95 wt. %, for example, 85 wt. % to 90 wt. %
  • potassium oxide can be present in an amount of 5 wt. % to 20 wt. %, for example, 8 wt. % to 10 wt. %.
  • the catalyst can selectively convert ethyl benzene to styrene while leaving the quantity of all other components present in stream 1 unaffected.
  • the operating conditions of the reactor unit 10 can be varied depending on circumstances such as equipment, feed composition, available resources, and other applicable conditions.
  • the dehydrogenation process of unit 10 can be conducted at a temperature of 500°C to 1,000°C, for example, 525°C to 800°C, for example, 540°C to 750°C.
  • the pressure within the dehydrogenation reactor can be atmospheric or sub-ambient, for example, -100 kPa to 200 kPa, for example, -75 kPa to 150 kPa, for example, -40 kPa to 105, kPa, for example, -25 kPa to 75 kPa.
  • the dehydrogenation catalyst can be added to the reaction mixture as a promoter in the presence of steam, where a ratio of steam to organic material can be 1:1 to 2:1, for example, 1:1 to 1.25:1. Steam can be present to facilitate reaction.
  • conversion and selectivity can vary. For example, the reaction can produce greater than or equal to 70 % conversion of the ethyl benzene fraction, while selectivity of conversion to styrene can be 90 % to 95 %.
  • the reaction, e.g., dehydrogenation reaction, in the dehydrogenation reactor can produce greater than or equal to 70% conversion of ethyl benzene, for example, greater than or equal to 80%, for example, greater than or equal to 90%.
  • the selectivity to styrene can be 75% to 99%, for example, 90% to 95%.
  • the hydrogen produced by the dehydrogenation reaction of unit 10 can be further separated and utilized in one or more upstream processes for efficiency purposes.
  • the hydrogen can be used as the fuel source for an upstream process or as feed hydrogen in an upstream hydrogenation process such as the hydrogenation of pyrolysis gasoline to remove olefins.
  • Stream 2 can contain the resulting reaction mixture produced by unit 10, e.g., dehydrogenation unit 10.
  • Stream 2 can optionally be passed through a heat recovery unit such as a shell and tube heat exchanger.
  • a heat recovery unit such as a shell and tube heat exchanger.
  • stream 2 prior to distillation, can be passed through a heat exchanger and cooled to a temperature of less than or equal to 200°C, for example, less than or equal to 175°C, for example, less than or equal to 160°C, for example, less than or equal to 125°C before entry to the divided wall distillation column.
  • a small amount of inhibitor can be added to the reactor more, for example, 4-tert butyl catechol (TBC) can be added to the resulting reaction mixture of stream 2 as an inhibitor to prevent styrene polymerization from occurring during the distillation process.
  • TBC 4-tert butyl catechol
  • the resulting reaction mixture contained in stream 2 can then be introduced into separation unit 20. Separation can be achieved by separation unit 20 through the use of a divided wall distillation column. Accordingly, separation unit 20 can be a divided wall distillation column 20.
  • the column can be operated under vacuum pressure, for example, 1 kiloPascal (kPa) to 500 kPa and a temperature of 120°C in the bottom portion.
  • the pressure can be 2.5 kPa to 100 kPa, for example, 5 kPa to 50 kPa, for example, 6.5 kPa to 40 kPa, for example, 10 kPa to 25 kPa.
  • the temperature can be greater than or equal to 75 °C, for example, greater than or equal to 100°C, for example, greater than or equal to 120°C, for example, greater than or equal to 150°C.
  • Styrene can be removed as a bottom product stream 5 of separation unit 20 from a bottom portion 22 of separation unit 20, i.e., divided wall distillation column 20 after passing through heat exchanger 27 through streams 21 and 23.
  • stream 21 can be a liquid stream (e.g., a 100% liquid stream) vaporized by a heating medium (e.g., steam).
  • Latent heat for vaporization can be provided in stream 21.
  • stream 21 can include a vapor-liquid mixture or can be a pure vapor so that a liquid stream having a temperature greater than stream 21 can be used to heat stream 21 (e.g., steam or another process stream in the plant having a temperature greater than or equal to 30°C higher than the temperature of stream 21) so that vapors can be formed in stream 23.
  • the vapors formed in stream 23 can assist in mass transfer of the various components and eventually in separation of components based upon their boiling point.
  • Water and unconverted xylenes can be withdrawn as a top product stream 3 from a top portion 24 of separation unit 20.
  • These components namely water, unconverted xylenes, and styrene, can be segregated simultaneously through the use of the separation unit 20 after passing through condenser 28 through streams 25 and 26.
  • stream 25 can be a vapor stream (e.g., a 100% vapor stream) using a cooling medium (e.g., water).
  • Latent heat can be removed through stream 25.
  • stream 25 can include vapors entering condenser 28, while stream 26 can contain condensed liquid that is refluxed back to the column to achieve the desired separation quality.
  • the condenser 28 is generally water cooled, but any process stream in the plant (e.g., any liquid with a temperature lower than stream 25 by greater than or equal to 30°C) can be used to cool stream 25.
  • the segregated styrene of stream 5 can then be further processed.
  • the styrene of stream 5 can be polymerized to create polystyrene.
  • the unconverted xylene materials of stream 3 can also be processed and utilized further.
  • the unconverted materials of stream 3 can be recycled to the unit 10, e.g., dehydrogenation reactor unit 10 for efficiency purposes.
  • Divided wall distillation column 20 as illustrated in Figure 1 can have a number of stages.
  • divided wall distillation column 20 can have a total of 40 stages, for example, a total of 60 stages, for example, a total of 75 stages. It is to be understood that the number of stages is not limited and can be higher than 75 stages or lower than 75 stages. An increased number of stages would increase capital investments costs due to higher height columns, but would require less heating in the reboiler. A decreased number of stages would decrease capital investment costs due to a lower column height but would require more heating in the reboiler, thereby increasing operating costs.
  • the divided wall within divided wall distillation column 20 can be located between various stages of the divided wall distillation column 20.
  • the divided wall within column 20 can be located between stages 20 and 40.
  • the location of the divided wall can assist in achieving the desired component separation and product quality.
  • the location of the stages can be determined so that a desired separation can be achieved with optimum energy output.
  • the location of the stages can be changed by 10% to 20% within the divided wall distillation column (depending upon the number of stages present in the divided wall) to accommodate for changes in the feed conditions in commercial plants
  • the unconverted materials of stream 3 can optionally be passed through a xylene splitter unit 30.
  • the xylene splitter 30 can be used to isolate m-xylene, p- xylene, o-xylene, unconverted ethyl benzene, or any other component of stream 3.
  • xylene splitter 30 can represent a process for isolating /?-xylene, e.g., the PAREXTM process.
  • the PAREXTM process can provide a means of purifying and recovering /?-xylene using a solid zeolitic adsorbent which is selective for /?-xylene.
  • the PAREXTM process simulates a moving bed of adsorbent with continuous counter-current flow of a liquid feed over the adsorbent. Feed and products can enter and leave the adsorbent bed continuously, at nearly constant compositions.
  • Xylene splitter 30 can optionally be a distillation column.
  • xylene splitter 30 can be a conventional distillation column or a divided wall distillation column.
  • the unconverted materials of stream 3 can then be processed in xylene splitter 30 and separated into a second product containing o-xylene as a bottom product stream 6 and withdrawn from a bottom portion 32 of xylene splitter 30 and first product containing unconverted materials stream 4 and withdrawn from a top portion 34 of xylene splitter 30.
  • Stream 4 e.g., first product, can include unconverted ethyl benzene, /?-xylene, and m-xylene.
  • Unconverted materials stream 4 can then be recycled back to the dehydrogenation reactor unit 10.
  • bottom product stream 6 can be removed from the bottom portion 32 of xylene splitter 30.
  • stream 31 can be a liquid stream (e.g., a 100% liquid stream) vaporized by a heating medium (e.g., steam). Latent heat for vaporization can be provided in stream 31.
  • stream 31 can include a vapor- liquid mixture or can be a pure vapor so that a liquid stream having a temperature greater than stream 31 can be used to heat stream 31 (e.g., steam or another process stream in the plant having a temperature greater than or equal to 30°C higher than the temperature of stream 21) so that vapors can be formed in stream 33.
  • the vapors formed in stream 33 can assist in mass transfer of the various components and eventually in separation of components based upon their boiling point.
  • top product stream 4 can be removed from the top portion 34 of xylene splitter 30.
  • stream 35 can be a vapor stream (e.g., a 100% vapor stream) using a cooling medium (e.g., water). Latent heat can be removed through stream 35.
  • stream 35 can include vapors entering condenser 38, while stream 36 can contain condensed liquid that is refluxed back to the column to achieve the desired separation quality.
  • the condenser 38 is generally water cooled, but any process stream in the plant (e.g., any liquid with a temperature lower than stream 35 by greater than or equal to 30°C) can be used to cool stream 25.
  • the feed stream 1 can be introduced into the divided wall distillation column 20 at any stage, for example, the feed stream 1 can be introduced into the divided wall distillation column 20 at stage 10. It is to be understood that feed stream 1 can be introduced at any stage within the divided wall distillation column 20. It can be desirable for the location to be located at stage 10 to achieve the desired separation at an optimum heat input.
  • the stage location of the feed stream 1 can be changed by 10% to 20% within the divided wall distillation column (depending upon the number of stages present in the divided wall) to accommodate for changes in the feed conditions in commercial plants.
  • Stream 5 can be withdrawn as a side product from the divided wall distillation column 20 at any stage, for example, stream 5 containing styrene can be withdrawn as a side product from the divided wall distillation column 20 at stages 40 to 60. It is to be understood that stream 5 containing styrene can be withdrawn at any stage within the divided wall distillation column 20. It can be desirable for the location to be located at stage 40 or stage 44 to achieve the desired separation at an optimum heat input. The withdrawal stage location of stream 5can be changed by 10% to 20% within the divided wall distillation column (depending upon the number of stages present in the divided wall) to accommodate for changes in the feed conditions in commercial plants.
  • a feed mixture of 20 wt. % to 65 wt. % ethyl benzene and remaining weight percentage mixed xylenes was contacted with a dehydrogenation catalyst within a dehydrogenation catalytic reactor. Water was fed alongside the feed mixture to act as a diluting agent and also as a heat source.
  • the catalyst comprised 85 wt. % to 90 wt.% ferric oxide, 8 wt. % to 10 wt. % potassium oxide as a promoter, and other additional metal oxides such as oxides of chromium, cerium, molybdenum, titanium, calcium, and magnesium as supplementary promoters.
  • Steam was present in the reactor at a steam to organic ratio of 1:1 to 1.25:1.
  • the temperature inside the reactor was 540°C to 750°C and the pressure inside the reactor was -40 kPa to 105 kPa. Greater than or equal to 70 percent conversion of the ethyl benzene fraction was achieved with a 90 percent to 95 percent selectivity to styrene.
  • the selective effect of the catalyst did not affect the quantity of the other species present in the feed mixture and thus allowed the selective conversion of only ethyl benzene to styrene.
  • the reaction mixture was cooled to 160°C through the use of a shell and tube heat exchanger.
  • a small amount of 4-tert butyl catechol was added to the reaction mixture as an inhibitor to prevent styrene polymerization from occurring during the distillation process.
  • the styrene was then separated from the mixture using a divided wall distillation column.
  • the column operated under vacuum pressure of 6.5 kPa to 40 kPa.
  • the bottom temperature of the column was 120°C.
  • Styrene was removed as the bottom product. Water and unconverted xylenes were withdrawn as the top product.
  • the use of a divided wall distillation column allowed the removal and segregation of the three components simultaneously, namely water, unconverted xylenes, and styrene.
  • Embodiment 1 A process for producing styrene, comprising: contacting a feed mixture comprising ethyl benzene and xylene with a dehydrogenation catalyst in a dehydrogenation reactor to form a reaction mixture comprising styrene, xylene, ethyl benzene, or a combination comprising at least one of the foregoing under operating conditions to produce a greater than or equal to 70% conversion of the ethyl benzene to styrene; and passing the reaction mixture through a divided wall distillation column to separate the styrene from the other components of the reaction mixture, wherein styrene is removed as a first product from the divided wall distillation column at a bottom portion of the divided wall distillation column and the other components of the reaction mixture are removed as a second product at a top portion of the divided wall distillation column.
  • Embodiment 2 The process of Embodiment 1, wherein the divided wall distillation column is operated at a pressure of 5 kiloPascals to 50 kiloPascals and a temperature of 120°C in the bottom portion of the divided wall distillation column.
  • Embodiment 3 A process for producing polystyrene, comprising: contacting a feed mixture comprising ethyl benzene and xylene with a dehydrogenation catalyst in a dehydrogenation reactor to form a reaction mixture comprising styrene, xylene, ethyl benzene, or a combination comprising at least one of the foregoing under operating conditions to produce a greater than or equal to 70% conversion of the ethyl benzene to styrene; passing the reaction mixture through a divided wall distillation column; separating the reaction mixture into fractions in the divided wall distillation column, wherein the fractions comprise styrene, xylene, and unconverted ethyl benzene; distributing the xylene and unconverted ethyl benzene fractions to a top portion of the divided wall distillation column; distributing the styrene to a bottom portion of the divided wall distillation
  • Embodiment 4 The process of any of Embodiments 1-3, wherein the source of the feed mixture is a catalytic reforming process, a steam cracking process, a gasoline separation process, an olefin separation process, a clay tower distillation process, or a combination comprising at least one of the foregoing.
  • the source of the feed mixture is a catalytic reforming process, a steam cracking process, a gasoline separation process, an olefin separation process, a clay tower distillation process, or a combination comprising at least one of the foregoing.
  • Embodiment 5 The process of any of Embodiments 1-4, wherein the feed mixture comprises 20 wt. % to 65 wt. % ethyl benzene.
  • Embodiment 6 The process of any of Embodiments 1-5, wherein the dehydrogenation catalyst comprises 85 wt. % to 90 wt. % ferric oxide; 8 wt. % to 10 wt. % potassium oxide; and chromium oxide, cerium oxide, molybdenum oxide, titanium oxide, calcium oxide, magnesium oxide, or a combination comprising at least one of the foregoing.
  • the dehydrogenation catalyst comprises 85 wt. % to 90 wt. % ferric oxide; 8 wt. % to 10 wt. % potassium oxide; and chromium oxide, cerium oxide, molybdenum oxide, titanium oxide, calcium oxide, magnesium oxide, or a combination comprising at least one of the foregoing.
  • Embodiment 7 The process of any of Embodiments 1-6, wherein steam is present in the dehydrogenation reactor and wherein the steam to organic ratio is 1:1 to 1.25:1.
  • Embodiment 8 The process of any of Embodiments 1-7, wherein the dehydrogenation reactor is operated at a temperature of 500°C to 1 ,000°C and a pressure of - 100 kiloPascals to 150 kiloPascals.
  • Embodiment 9 The process of any of Embodiments 1-8, wherein the dehydrogenation reactor is operated at a temperature of 540°C to 750°C and a pressure of -40 kiloPascals to 105 kiloPascals.
  • Embodiment 10 The process of any of Embodiments 1-9, wherein the reaction in the dehydrogenation reactor produces greater than or equal to a 80 percent conversion of the ethyl benzene, wherein the selectivity to styrene is 90 percent to 95 percent.
  • Embodiment 11 The process of any of Embodiments 1-10, wherein ethyl benzene is converted by a dehydrogenation reaction in the dehydrogenation reactor with selectivity toward styrene greater than or equal to 90%.
  • Embodiment 12 The process of any of Embodiments 1-11, further comprising feeding water to the dehydrogenation reactor alongside the feed mixture.
  • Embodiment 13 The process of any of Embodiments 1-12, wherein hydrogen produced by the reaction in the dehydrogenation reactor is used as source hydrogen for an upstream hydrogenation process, fuel for an upstream process, or a combination comprising at least one of the foregoing.
  • Embodiment 14 The process of any of Embodiments 1-13, further comprising passing the reaction mixture through a heat recovery unit and cooling the reaction mixture to a temperature of less than or equal to 160°C.
  • Embodiment 15 The process of any of Embodiments 1-14, further comprising adding an inhibitor to the reaction mixture before entering the divided wall distillation column.
  • Embodiment 16 The method of Embodiment 15, wherein the inhibitor is 4- tert butyl catechol.
  • Embodiment 17 The process of any of Embodiments 1-16, wherein the top product of the divided wall distillation column comprises water and unconverted materials.
  • Embodiment 18 The process of any of Embodiments 1-17, further comprising processing the styrene to produce polystyrene.
  • Embodiment 19 The process of any of Embodiments 1-18, further comprising passing the unconverted materials through a separation unit, wherein unconverted ethyl benzene, /?-xylene, o-xylene, m-xylene, or a combination comprising at least one of the foregoing is isolated in the separation unit.
  • Embodiment 20 The process of Embodiment 19, further comprising withdrawing a first product comprising unconverted ethyl benzene, /?-xylene, and m-xylene from a top portion of the separation unit and withdrawing a second product comprising o- xylene from a bottom portion of the separation unit.
  • Embodiment 21 The process of any of Embodiments 1-19, further comprising recycling the unconverted materials to the dehydrogenation reactor.
  • Embodiment 22 The process of Embodiment 21, wherein the first product is recycled to the dehydrogenation reactor.
  • the process disclosed herein provides a divided wall distillation column being used in the ethyl benzene dehydrogenation process.
  • the result is a more efficient and cost effective styrene production process. Separation of ethyl benzene from an aromatic hydrocarbon mixture is achieved using a single divided wall column instead of two separate tall columns.
  • the use of a divided wall distillation column in the process further allows the removal and segregation of the three main components simultaneously, namely water, unconverted xylenes, and styrene.
  • the ethyl benzene fraction of the aromatic hydrocarbon mixture has little value and normally has to be converted into xylenes.
  • the process of the present disclosure allows this low value ethyl benzene fraction to be upgraded to styrene and removed from the stream in a more efficient manner than previously disclosed.
  • the invention may alternately comprise, consist of, or consist essentially of, any appropriate components herein disclosed.
  • the invention may additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any components, materials, ingredients, adjuvants or species used in the prior art compositions or that are otherwise not necessary to the achievement of the function and/or objectives of the present invention.

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Abstract

La présente invention concerne un procédé de production de styrène, consistant : à mettre en contact un mélange d'alimentation comprenant de l'éthyl benzène et du xylène avec un catalyseur de déshydrogénation dans un réacteur de déshydrogénation pour former un mélange réactionnel comprenant du styrène, du xylène, de l'éthyl benzène, ou une combinaison comprenant au moins l'un des éléments qui précèdent dans des conditions de fonctionnement pour produire une conversion supérieure ou égale à 70 % de l'éthyl benzène en styrène ; et à faire passer le mélange réactionnel à travers une colonne de distillation à paroi divisée pour séparer le styrène des autres constituants du mélange réactionnel, le styrène étant retiré en tant que premier produit de la colonne de distillation à paroi divisée au niveau d'une partie inférieure de la colonne de distillation à paroi divisée et les autres constituants du mélange réactionnel étant retirés sous la forme d'un second produit au niveau d'une partie supérieure de la colonne de distillation à paroi divisée.
PCT/IB2016/053372 2015-06-09 2016-06-08 Procédé pour la production de styrène à partir de xylène par déshydrogénation d'éthyl benzène WO2016199040A1 (fr)

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CN114096505A (zh) * 2020-06-16 2022-02-25 株式会社Lg化学 生产芳香烃的方法

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US5386075A (en) * 1992-10-21 1995-01-31 Huels Aktiengesellschaft Process for separating ethylbenzene and styrene by distillation
WO2010078098A1 (fr) * 2008-12-31 2010-07-08 Fina Technology, Inc. Procédés mettant en oeuvre une colonne de distillation à séparation interne
CN101348412B (zh) * 2007-07-18 2011-07-20 中国石油化工股份有限公司 用于苯乙烯精馏的节能方法
CN101429088B (zh) * 2007-11-07 2012-01-25 中国石油化工股份有限公司 用于分离含乙苯和苯乙烯物流的精馏方法
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US5386075A (en) * 1992-10-21 1995-01-31 Huels Aktiengesellschaft Process for separating ethylbenzene and styrene by distillation
CN101348412B (zh) * 2007-07-18 2011-07-20 中国石油化工股份有限公司 用于苯乙烯精馏的节能方法
CN101429088B (zh) * 2007-11-07 2012-01-25 中国石油化工股份有限公司 用于分离含乙苯和苯乙烯物流的精馏方法
WO2010078098A1 (fr) * 2008-12-31 2010-07-08 Fina Technology, Inc. Procédés mettant en oeuvre une colonne de distillation à séparation interne
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114096505A (zh) * 2020-06-16 2022-02-25 株式会社Lg化学 生产芳香烃的方法
CN114096505B (zh) * 2020-06-16 2023-12-01 株式会社Lg化学 生产芳香烃的方法

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