WO2015187363A1 - Transalkylation de charges d'hydrocarbures aromatiques lourds - Google Patents

Transalkylation de charges d'hydrocarbures aromatiques lourds Download PDF

Info

Publication number
WO2015187363A1
WO2015187363A1 PCT/US2015/031671 US2015031671W WO2015187363A1 WO 2015187363 A1 WO2015187363 A1 WO 2015187363A1 US 2015031671 W US2015031671 W US 2015031671W WO 2015187363 A1 WO2015187363 A1 WO 2015187363A1
Authority
WO
WIPO (PCT)
Prior art keywords
catalyst
catalyst composition
molecular sieve
zsm
feed
Prior art date
Application number
PCT/US2015/031671
Other languages
English (en)
Inventor
Jeevan S. Abichandani
Gary D. Mohr
Robert G. TINGER
Original Assignee
Exxonmobil Chemical Patents Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Exxonmobil Chemical Patents Inc. filed Critical Exxonmobil Chemical Patents Inc.
Publication of WO2015187363A1 publication Critical patent/WO2015187363A1/fr

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C6/00—Preparation of hydrocarbons from hydrocarbons containing a different number of carbon atoms by redistribution reactions
    • C07C6/08—Preparation of hydrocarbons from hydrocarbons containing a different number of carbon atoms by redistribution reactions by conversion at a saturated carbon-to-carbon bond
    • C07C6/12—Preparation of hydrocarbons from hydrocarbons containing a different number of carbon atoms by redistribution reactions by conversion at a saturated carbon-to-carbon bond of exclusively hydrocarbons containing a six-membered aromatic ring
    • C07C6/126—Preparation of hydrocarbons from hydrocarbons containing a different number of carbon atoms by redistribution reactions by conversion at a saturated carbon-to-carbon bond of exclusively hydrocarbons containing a six-membered aromatic ring of more than one hydrocarbon
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C4/00—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms
    • C07C4/08—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by splitting-off an aliphatic or cycloaliphatic part from the molecule
    • C07C4/12—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by splitting-off an aliphatic or cycloaliphatic part from the molecule from hydrocarbons containing a six-membered aromatic ring, e.g. propyltoluene to vinyltoluene
    • C07C4/14—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by splitting-off an aliphatic or cycloaliphatic part from the molecule from hydrocarbons containing a six-membered aromatic ring, e.g. propyltoluene to vinyltoluene splitting taking place at an aromatic-aliphatic bond
    • C07C4/18—Catalytic processes
    • 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
    • C07C5/02—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by hydrogenation
    • C07C5/03—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by hydrogenation of non-aromatic carbon-to-carbon double bonds
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2521/00—Catalysts comprising the elements, oxides or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium or hafnium
    • C07C2521/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
    • C07C2521/08—Silica
    • 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
    • C07C2523/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of noble metals
    • C07C2523/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of noble metals of the platinum group metals
    • C07C2523/42—Platinum
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2529/00—Catalysts comprising molecular sieves
    • C07C2529/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites, pillared clays
    • C07C2529/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • C07C2529/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11

Definitions

  • This disclosure relates to transalkylation of heavy (C 9+ ) aromatic hydrocarbon feedstocks to produce xylene and either benzene or toluene.
  • catalytic reformate which is produced by contacting a mixture of petroleum naphtha and hydrogen with a strong hydrogenation/dehydrogenation catalyst, such as platinum, on a moderately acidic support, such as a halogen-treated alumina.
  • a Ce to Cs fraction is separated from the reformate and extracted with a solvent selective for aromatics or aliphatics to produce a mixture of aromatic compounds that is relatively free of aliphatics.
  • This mixture of aromatic compounds contains benzene, toluene and xylenes (BTX), along with ethylbenzene, and can be processed in known manner to recover the xylene.
  • the transalkylation reaction product is then contacted with a second catalyst composition which comprises a molecular sieve having a constraint index ranging from 3 to 12, such as ZSM-5, and which may be in a separate bed or a separate reactor from the first catalyst composition, under conditions to remove benzene co-boilers in the product.
  • a second catalyst composition which comprises a molecular sieve having a constraint index ranging from 3 to 12, such as ZSM-5, and which may be in a separate bed or a separate reactor from the first catalyst composition, under conditions to remove benzene co-boilers in the product.
  • US 2009/0112034 discloses a catalyst system adapted for transalkylation of a C9+ aromatic feedstock with a C6-C7 aromatic feedstock comprising: (a) a first catalyst comprising a first molecular sieve having a Constraint Index in the range of 3-12 and 0.01 to 5 wt.% of at least one source of a first metal element of Groups 6-10; and (b) a second catalyst comprising a second molecular sieve having a Constraint Index less than 3 and 0 to 5 wt.% of at least one source of a second metal element of Groups 6-10, wherein the weight ratio of said first catalyst to said second catalyst is in the range of 5:95 to 75:25.
  • the first catalyst which is optimized for dealkylation of the ethyl and propyl groups in the feed, is located in front of the second catalyst, which is optimized for transalkylation, when they are brought into contact with a C 9 + aromatic feedstock and a C6-C7 aromatic feedstock in the presence of hydrogen.
  • the second catalyst which is optimized for transalkylation, when they are brought into contact with a C 9 + aromatic feedstock and a C6-C7 aromatic feedstock in the presence of hydrogen.
  • the cycle life and aromatic yields in the production of xylene from C9+ aromatic hydrocarbons can be improved by reducing or eliminating the alumina conventionally employed as the binder for the molecular sieve catalysts used in existing transalkylation processes.
  • the alumina binder provides external active sites for coke formation which accelerates catalyst aging and hence reduces cycle time.
  • the present disclosure relates to a process for producing xylene from C9+ aromatic hydrocarbons. The process comprises at least two steps.
  • the first step is contacting a first feed comprising C9+ aromatic hydrocarbons, at least one C6-C7 aromatic hydrocarbon and hydrogen with a first catalyst composition under conditions effective to dealkylate at least part of the C9+ aromatic hydrocarbons containing C2+ alkyl groups and to saturate the resulting C2+ olefins to produce a second feed.
  • the first catalyst composition comprises a first molecular sieve having a Constraint Index of 3 to 12 and a hydrogenation component and the second step is contacting the second feed with a second catalyst composition under conditions effective for transalkylation of at least part of the C9+ aromatic hydrocarbons in the second feed with at least part of the C6-C7 aromatic hydrocarbon in the second feed to produce a first product comprising xylene.
  • the second catalyst composition comprises a second molecular sieve having a Constraint Index less than 3.
  • each of the first and second catalyst compositions is substantially free of amorphous alumina.
  • the first and second catalyst compositions is substantially binder- free or comprises a silica binder or a binder comprising a crystalline molecular sieve.
  • the first molecular sieve typically comprises ZSM-5 and the second molecular sieve comprises ZSM-12.
  • the process can further comprise a third step, wherein at least a portion of the first product is contacted with a third catalyst composition under conditions effective to remove benzene coboilers in the first product and produce a second product, wherein the third catalyst composition comprises a third molecular sieve having a Constraint Index of 3 to 12 and is substantially free of amorphous alumina.
  • the present disclosure relates to a catalyst system for transalkylating a feed comprising C9+ aromatic hydrocarbons to produce xylene.
  • the catalyst system comprises at least three catalyst compositions.
  • the first catalyst composition comprises a first molecular sieve having a Constraint Index of 3 to 12 and a hydrogenation component.
  • the second catalyst composition comprises a second molecular sieve having a Constraint Index less than 3.
  • the second catalyst composition is located downstream of the first catalyst composition when the catalyst system is contacted with the feed.
  • the third catalyst composition comprises a third molecular sieve having a Constraint Index of 3 to 12.
  • the third catalyst composition being located downstream of the second catalyst composition when the catalyst system is contacted with the feed.
  • Each of the first, second and third catalyst compositions is substantially free of amorphous alumina.
  • Figure 1 is a graph plotting top bed normalized average reactor temperature (NART) and coke make against days on stream (DOS) for the heavy aromatic conversion processes of Example 1 (using a silica-bound PtZSM-5 catalyst) and Comparative Example 1 (using an alumina-bound PtZSM-5 catalyst).
  • Figure 2 is a graph of wt% ethyl-aromatic conversion against top bed NART for the heavy aromatic conversion processes of Example 1 and Comparative Example 1.
  • aromatic is used herein in accordance with its art-recognized scope which includes alkyl substituted and unsubstituted mono- and polynuclear compounds.
  • ethyl-aromatic compounds means aromatic compounds having an ethyl group attached to the aromatic ring.
  • propyl-aromatic compounds means aromatic compounds having a propyl group attached to the aromatic ring.
  • C n hydrocarbon or aromatic as used herein means a hydrocarbon or aromatic compound having n number of carbon atom(s) per molecule.
  • C n+ hydrocarbon or aromatic means hydrocarbon or aromatic compound having n or more than n carbon atom(s) per molecule.
  • C n - hydrocarbon or aromatic means a hydrocarbon or aromatic compound having less than n carbon atom(s) per molecule.
  • substantially free when used in relation to a specific component of a catalyst composition means that the catalyst composition contains less than 1 wt.%, preferably less than 0.15 wt.%, of that component.
  • Aromatic Ring loss (%) (1 -total moles of aromatic compounds in product/total moles of aromatic compounds in feed)* 100.
  • benzene co-boiler means impurities that have a boiling point close to the boiling point of benzene as described at page 393 of Aromatic Hydrocarbons - Advances in Research and Treatment, 2013 Edition, Acton, Q.A. Ed., Scholarly Editions, Atlanta, Georgia (2013).
  • Described herein is a process for producing xylenes from C9+ aromatic hydrocarbons using a series-connected multiple bed catalyst system.
  • the process employs a first catalyst bed comprising a first catalyst composition selective for the dealkylation of ethyl-aromatic compounds and propyl-aromatic compounds in the C 9 + aromatic hydrocarbon feed.
  • a second catalyst bed Downstream of the first catalyst bed is a second catalyst bed comprising a second catalyst composition effective to transalkylate C 9 + aromatic hydrocarbons with cofed benzene and/or toluene to produce xylenes.
  • the xylene-containing product of the trans alky lation step is then passed to a third catalyst bed which is located downstream of the second catalyst bed and which comprises a third catalyst composition effective to remove benzene co-boilers in the product.
  • the third catalyst bed is omitted and the process employs the first and second catalysts beds only. Preferably, however, the process employs the first, second, and third, catalyst beds.
  • Each catalyst bed can be housed in a separate reactor or, where desired, two or more of the catalysts beds can be accommodated in the same reactor.
  • the first, second, and third, catalyst beds can be stacked one on top of the other in a single reactor.
  • the aromatic feed used in the present process comprises one or more aromatic hydrocarbons containing at least 9 carbon atoms.
  • Specific C9+ aromatic compounds found in a typical feed include mesitylene (1,3,5-trimethylbenzene), durene (1,2,4,5- tetramethylbenzene), hemimellitene (1,2,4-trimethylbenzene), pseudocumene (1,2,4- trimethylbenzene), 1 ,2-methylethylbenzene, 1,3-methylethylbenzene, 1,4- methylethylbenzene, propyl-substituted benzenes, butyl-substituted benzenes, and dimethylethylbenzenes.
  • Suitable sources of the C9+ aromatics are any C9+ fraction from any refinery process that is rich in aromatics.
  • This aromatics fraction contains a substantial proportion of Cg + aromatics, e.g., at least 80 wt.% Cg + aromatics, wherein preferably at least 80 wt.%, and more preferably more than 90 wt.%, of the hydrocarbons will range from C9 to C12.
  • Typical refinery fractions which may be useful include catalytic reformate, FCC naphtha or TCC naphtha.
  • the feed to the process also includes benzene and/or toluene.
  • the feed to the trans alky lation reactor comprises C9+ aromatics hydrocarbons and toluene.
  • the feed may also include recycled/unreacted toluene and C9+ aromatic feedstock that is obtained by distillation of the effluent product of the trans alky lation reaction itself.
  • toluene constitutes from 0 to 90 wt.%, such as from 10 to 70 wt.% of the entire feed
  • the C9+ aromatics component constitutes from 10 to 100 wt.%, such as from 30 to 85 wt.% of the entire feed to the process.
  • the feed to the process will also normally include hydrogen to saturate the C2+ olefins generated by the dealkylation reactions occurring in the optional first catalyst bed.
  • the first catalyst bed employed in the present catalyst system contains a first catalyst composition comprising a first molecular sieve having a Constraint
  • Constraint Index is a convenient measure of the extent to which an aluminosilicate or other molecular sieve provides controlled access to molecules of varying sizes to its internal structure.
  • molecular sieves which provide a highly restricted access to and egress from its internal structure have a high value for the Constraint Index.
  • Molecular sieves of this kind usually have pores of small diameter, e.g., less than 5 Angstroms.
  • molecular sieves which provide relatively free access to their internal pore structure have a low value for the constraint index, and usually pores of large size.
  • Suitable molecular sieves for use in the first catalyst composition comprise at least one of ZSM-5, ZSM-11, ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-57, and ZSM-58.
  • ZSM-5 is described in detail in US 3,702,886 and Re. 29,948.
  • ZSM-1 1 is described in detail in
  • ZSM-22 is described in U.S. Patent Nos. 4,556,477 and 5,336,478.
  • ZSM-23 is described in US 4,076,842.
  • ZSM-35 is described in US 4,016,245.
  • ZSM-48 is more particularly described in US 4,234,231 and US 4,375,573.
  • ZSM-57 is described in US 4,873,067.
  • ZSM-58 is described in US 4,698,217.
  • the first molecular sieve comprises ZSM-5 and especially ZSM-5 having an average crystal size of less than 0.1 micron, for example such that the ZSM-5 crystals have an external surface area in excess of 100 m 2 /g as determined by the t-plot method for nitrogen physisorption.
  • Suitable ZSM-5 compositions are disclosed in PCT/US2013/071456, filed November 22, 2013 (which claims priority to USSN 61/740,908, filed December 21, 2012) and PCT/US2013/071446, filed November 22, 2013 (which claims priority to USSN 61/740,917, filed December 21, 2012, the entire contents of which are incorporated herein by reference).
  • the first molecular sieve has an alpha value in the range of about 100 to about 1500, such as about 150 to about 1000, for example, about 150 to about 600.
  • Alpha value is a measure of the cracking activity of a catalyst and is described in US 3,354,078 and in the Journal of Catalysis, Vol. 4, p. 527 (1965); Vol. 6, p. 278 (1966); and Vol. 61, p. 395 (1980), each incorporated herein by reference as to that description.
  • the experimental conditions of the test used herein include a constant temperature of 538°C and a variable flow rate as described in detail in the Journal of Catalysis, Vol. 61, p. 395.
  • the first molecular sieve is an aluminosilicate having a silica to alumina molar ratio of less than 1000. Typically, the silica to alumina molar ratio is from about 10 to about 100.
  • the first catalyst composition comprises at least 1 wt.%, preferably at least 10 wt.%, more preferably at least 25 wt.%, and most preferably at least 50 wt.%, of the first molecular sieve. In one embodiment, the first catalyst composition comprises from 55 to 80 wt.% of the first molecular sieve.
  • the first catalyst composition comprises at least one hydrogenation component, such as at least one metal or compound thereof of Groups 6 to 12 of the Periodic Table of the Elements.
  • Suitable hydrogenation components include platinum, palladium, iridium, rhenium, and mixtures and compounds thereof, preferably platinum, rhenium, and compounds thereof.
  • the first catalyst composition comprises two or more hydrogenation components including a first metal or compound thereof selected from platinum, palladium, iridium, rhenium, and mixtures thereof, and a second metal or compound chosen so as to lower the benzene saturation activity of the first metal.
  • suitable second metals include at least one of copper, silver, gold, ruthenium, iron, tungsten, molybdenum, cobalt, nickel, tin, and zinc.
  • the first metal is present in the first catalyst in an amount from 0.001 to 1 wt.%, such as from 0.01 to 0.1 wt.%, of the first catalyst and the second metal is present in the first catalyst in amount from 0.001 to 10 wt.%, or 0.1 to 1 wt.%, of the first catalyst.
  • the first metal comprises platinum and/or rhenium and the second metal comprises copper and/or tin.
  • the first metal comprises platinum and the second metal comprises tin, desirably at a molar ratio of platinum to tin from 0.1 : 1 to 1 : 1, such as from 0.2: 1 to 0.4: 1.
  • the hydrogenation component can be incorporated into the first catalyst composition by any known method, including co-crystallization, ion exchange into the composition to the extent a Group 13 element, e.g., aluminum, is in the molecular sieve structure, impregnated therein, or mixed with the molecular sieve and binder. In some embodiments, ion exchange may be preferred.
  • the catalyst composition is usually dried by heating at a temperature of 65°C to 160°C, typically 1 10°C to 143°C, for at least 1 minute and generally not longer than 24 hours, at pressures ranging from 100 to 200 kPa-a.
  • the catalyst composition may be calcined in a stream of dry gas, such as air or nitrogen, at temperatures of from 260°C to 650°C for 1 to 20 hours. Calcination is typically conducted at pressures ranging from 100 to 300 kPa-a.
  • the hydrogenation component may be treated (such as by sulfiding) to alter the activity of the hydrogenation catalyst.
  • a method for minimizing the aromatics hydrogenation activity of the catalyst composition is by exposing it to a compound containing an element selected from group 15 or 16 of the Periodic Table of the Elements, preferably N, P, S, O.
  • the group 16 element specifically contemplated is sulfur.
  • a specifically contemplated group 15 element is nitrogen.
  • Effective treatment is accomplished by contacting the catalyst with a source of sulfur at a temperature ranging from about 200° to 480°C.
  • the source of sulfur can be contacted with the catalyst via a carrier gas, typically, an inert gas such as hydrogen or nitrogen.
  • the source of sulfur is typically hydrogen sulfide.
  • the catalyst composition can also be treated in situ.
  • a source of sulfur is contacted with the catalyst composition by adding it to the hydrocarbon feedstream in a concentration ranging from about 50 ppmw sulfur to about 10,000 ppmw sulfur. Any sulfur compound that will decompose to form 3 ⁇ 4 S and a light hydrocarbon at about 490°C or less will suffice.
  • Typical examples of useful sources of sulfur include carbon disulfide and alkylsulfides such as methylsulfide, dimethylsulfide, dimethyldisulfide, diethylsulfide and dibutyl sulfide. Sulfur treatment can be considered sufficient when sulfur breakthrough occurs; that is, when sulfur appears in the liquid product.
  • sulfur treatment is initiated by incorporating a source of sulfur into the feed and continuing sulfur treatment for a few days, typically, up to 10 days, more specifically, from one to five days.
  • the sulfur treatment can be monitored by measuring the concentration of sulfur in the product off gas.
  • the sulfur concentration in the off gas should range from about 20 to about 500 ppmw sulfur, preferably about 30 to 250 ppmw.
  • the catalyst can be contacted with sulfur during service by cofeeding sulfur to the reactor in varied amounts via the hydrogen stream entering the reactor or the hydrocarbon feedstock.
  • the sulfur can be continuously added to the feedstock throughout the process cycle or the sulfur can be intermittently continuously added in which this sulfur is cofed continuously for a period of time, discontinued, then cofed again.
  • the first catalyst composition may be self-bound (that is without a separate binder) or may also comprise a binder or matrix material that is resistant to the temperatures and other conditions employed in the present process. Where such a binder or matrix material is present, it is substantially free of amorphous alumina, since it is found that the exclusion of a binder containing amorphous alumina reduces external catalytic sites for coke production and hence increases catalyst cycle length.
  • One preferred binder material for the first catalyst composition comprises silica since extrusion with silica ensures that the catalyst has high mesoporosity and hence high activity.
  • the binder or matrix material may be a crystalline molecular sieve material, which may be isostructural with, or have a different structure than, the first molecular sieve.
  • the first catalyst composition contains a binder or matrix material
  • the latter may be present in an amount ranging from 5 to 95 wt.% of the total catalyst composition.
  • the matrix material is present in an amount ranging from 10 to 60 wt.% of the total catalyst composition.
  • the first catalyst composition may be extruded into particles of any desired shape before being loaded into the first catalyst bed.
  • Suitable particle configurations for achieving such a surface to volume ratio include grooved cylindrical extrudates and hollow or solid polylobal extrudates, such as quadrulobal extrudates.
  • the first catalyst composition comprises from 10 wt.% to 50 wt% of the total weight of the first, second and third catalyst compositions.
  • the first catalyst composition may comprise from 15 wt% to 35 wt%, of the total weight of the first, second and third catalyst compositions.
  • the first catalyst bed is maintained under conditions effective to dealkylate aromatic hydrocarbons containing C2+ alkyl groups in the heavy aromatic feedstock and to saturate the resulting C2+ olefins.
  • Suitable conditions for operation of the first catalyst bed comprise a temperature in the range of about 100 to about 800°C, preferably about 300 to about 500°C, a pressure in the range of about 790 to about 7000 kPa-a, preferably about 2170 to 3000 kPa-a, a H2:HC molar ratio in the range of about 0.01 to about 20, preferably about 1 to about 10, and a WHSV in the range of about 0.01 to about 100 hr "1 , preferably about 2 to about 20 hr "1 .
  • the second catalyst bed contains a second catalyst composition comprising a second molecular sieve different from the first molecular sieve.
  • the second catalyst bed may contain one or more hydrogenation components.
  • the second molecular sieve has a Constraint Index less than 3 and may comprise at least one of zeolite beta, zeolite Y, Ultrastable Y (USY), Dealuminized Y (Deal Y), mordenite, NU-87, ZSM-3, ZSM-4 (Mazzite), ZSM-12, ZSM-18, MCM-22, PSH-3, SSZ- 25, MCM-36, MCM-49, MCM-56, EMM- 10, EMM-10-P and ZSM-20.
  • Zeolite ZSM-4 is described in US 3,923,636.
  • Zeolite ZSM-12 is described in US 3,832,449.
  • Zeolite ZSM-20 is described in US 3,972,983.
  • Zeolite Beta is described in US 3,308,069, and Re. 28,341.
  • Low sodium Ultrastable Y molecular sieve USY
  • Dealuminized Y zeolite (Deal Y) may be prepared by the method found in US 3,442,795.
  • Zeolite UHP-Y is described in US 4,401,556.
  • Rare earth exchanged Y (REY) is described in US 3,524,820.
  • Mordenite is a naturally occurring material but is also available in synthetic forms, such as TEA-mordenite (i.e., synthetic mordenite prepared from a reaction mixture comprising a tetraethylammonium directing agent).
  • TEA-mordenite is disclosed in US 3,766,093 and US 3,894,104.
  • MCM-22 is described in US 4,954,325.
  • PSH- 3 is described in US 4,439,409.
  • SSZ-25 is described in US 4,826,667.
  • MCM-36 is described in US 5,250,277.
  • MCM-49 is described in US 5,236,575.
  • MCM-56 is described in US 5,362,697.
  • the second catalyst composition comprises at least 1 wt.%, preferably at least 10 wt.%, more preferably at least 25 wt.%, and most preferably at least 50 wt.%, of the second molecular sieve.
  • the first catalyst composition comprises from 55 to 80 wt.% of the second molecular sieve.
  • the second molecular sieve comprises ZSM-12. More preferably, the molecular sieve comprises ZSM-12 having an average crystal size of less than 0.1 micron, such as about 0.05 micron.
  • the second catalyst composition optionally comprises at least one hydrogenation component, such as at least one metal or compound thereof of Groups 6 to 12 of the Periodic Table of the Elements.
  • Suitable hydrogenation components include platinum, palladium, iridium, rhenium and mixtures and compounds thereof, preferably platinum, rhenium and compounds thereof.
  • the second catalyst composition comprises two or more hydrogenation components including a first metal or compound thereof selected from platinum, palladium, iridium, rhenium and mixtures thereof and a second metal or compound chosen so as to lower the benzene saturation activity of the first metal.
  • suitable second metals include at least one of copper, silver, gold, ruthenium, iron, tungsten, molybdenum, cobalt, nickel, tin and zinc.
  • the first metal is present in the second catalyst in an amount from 0.001 to 1 wt.%, such as from 0.01 to 0.1 wt.%, of the second catalyst and the second metal is present in the second catalyst in amount from 0.001 to 10 wt.%, 0.1 to 1 wt.%, of the second catalyst.
  • the first metal comprises platinum and/or rhenium and the second metal comprises copper and/or tin.
  • the first metal comprises platinum and the second metal comprises tin, desirably at a molar ratio of platinum to tin from 0.1 : 1 to 1 : 1, such as from 0.2: 1 to 0.4: 1.
  • the hydrogenation component can be incorporated into the second catalyst composition by any known method, including co-crystallization, ion exchange into the composition to the extent a Group 13 element, e.g., aluminum, is in the molecular sieve structure, impregnated therein, or mixed with the molecular sieve and binder. In some embodiments, ion exchange may be preferred.
  • the catalyst composition is usually dried by heating at a temperature of 65°C to 160°C, typically 1 10°C to 143°C, for at least 1 minute and generally not longer than 24 hours, at pressures ranging from 100 to 200 kPa-a.
  • the catalyst composition may be calcined in a stream of dry gas, such as air or nitrogen, at temperatures of from 260°C to 650°C for 1 to 20 hours. Calcination is typically conducted at pressures ranging from 100 to 300 kPa-a.
  • dry gas such as air or nitrogen
  • a method for minimizing the aromatics hydrogenation activity of the catalyst composition is by exposing it to a compound containing an element selected from group 15 or 16 of the Periodic Table of the Elements, preferably N, P, S, O.
  • the group 16 element specifically contemplated is sulfur.
  • a specifically contemplated group 15 element is nitrogen.
  • Effective treatment is accomplished by contacting the catalyst with a source of sulfur at a temperature ranging from about 200° to 480°C.
  • the source of sulfur can be contacted with the catalyst via a carrier gas, typically, an inert gas such as hydrogen or nitrogen.
  • the source of sulfur is typically hydrogen sulfide.
  • the catalyst composition can also be treated in situ.
  • a source of sulfur is contacted with the catalyst composition by adding it to the hydrocarbon feedstream in a concentration ranging from about 50 ppmw sulfur to about 10,000 ppmw sulfur. Any sulfur compound that will decompose to form 3 ⁇ 4 S and a light hydrocarbon at about 490°C or less will suffice.
  • Typical examples of useful sources of sulfur include carbon disulfide and alkylsulfides such as methylsulfide, dimethylsulfide, dimethyldisulfide, diethylsulfide and dibutyl sulfide. Sulfur treatment can be considered sufficient when sulfur breakthrough occurs; that is, when sulfur appears in the liquid product.
  • sulfur treatment is initiated by incorporating a source of sulfur into the feed and continuing sulfur treatment for a few days, typically, up to 10 days, more specifically, from one to five days.
  • the sulfur treatment can be monitored by measuring the concentration of sulfur in the product off gas.
  • the sulfur concentration in the off gas should range from about 20 to about 500 ppmw sulfur, preferably about 30 to 250 ppmw.
  • the catalyst can be contacted with sulfur during service by cofeeding sulfur to the reactor in varied amounts via the hydrogen stream entering the reactor or the hydrocarbon feedstock.
  • the sulfur can be continuously added to the feedstock throughout the process cycle or the sulfur can be intermittently continuously added in which this sulfur is cofed continuously for a period of time, discontinued, then cofed again.
  • Such sulfur treatments are effective at any temperature for a metal that is already fully reduced, which can be limited by the thermal decomposition temperature of the sulfiding agent to H 2 S.
  • the second catalyst composition may be self-bound (that is without a separate binder) or may also comprise a binder or matrix material that is resistant to the temperatures and other conditions employed in the present process. Where such a binder or matrix material is present, it is preferably substantially free of amorphous alumina, since it is found that the exclusion of a binder containing amorphous alumina reduces external catalytic sites for coke production and hence increases catalyst cycle length.
  • One preferred binder material for the second catalyst composition comprises silica since extrusion with silica ensures that the catalyst has high mesoporosity and hence high activity.
  • the binder or matrix material may be a crystalline molecular sieve material, which may be isostructural with, or have a different structure than, the third molecular sieve.
  • each of the first and second catalyst compositions includes a silica binder.
  • the second catalyst composition may be extruded into particles of any desired shape before being loaded into the second catalyst bed.
  • Suitable particle configurations for achieving such a surface to volume ratio include grooved cylindrical extrudates and hollow or solid polylobal extrudates, such as quadrulobal extrudates.
  • the second catalyst composition comprises from 30 wt% to 90 wt% of the total of the first, second and third catalyst compositions.
  • the second catalyst composition may comprise from 50 wt% to 75 wt% of the total weight of the first, second and third catalyst compositions.
  • the second catalyst bed is maintained under conditions effective to transalkylate C9+ aromatic hydrocarbons with said at least one C6-C7 aromatic hydrocarbon.
  • Suitable conditions for operation of the second catalyst bed comprise a temperature in the range of about 100 to about 800°C, preferably about 300 to about 500°C, a pressure in the range of about 790 to about 7000 kPa-a, preferably about 2170 to 3000 kPa-a, a H2:HC molar ratio in the range of about 0.01 to about 20, preferably about 1 to about 10, and a WHSV in the range of about 0.01 to about 100 hr "1 , preferably about 1 to about 10 hr "1 .
  • the third catalyst bed employed in the present catalyst system contains a third catalyst composition comprising a third molecular sieve having a Constraint Index in the range of about 3 to about 12.
  • Suitable molecular sieves for use in the third catalyst composition comprise at least one of ZSM-5, ZSM-11, ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-57 and ZSM-58, with ZSM-5 being preferred.
  • the third molecular sieve comprises ZSM-5 and especially ZSM-5 having an average crystal size of less than 0.1 micron, for example such that the ZSM-5 crystals have an external surface area in excess of 100 m 2 /g as determined by the t-plot method for nitrogen physisorption.
  • Suitable ZSM-5 compositions are disclosed in
  • the third molecular sieve has an alpha value in the range of about
  • 100 to about 1500 such as about 150 to about 1000, for example about 150 to about 600.
  • the third catalyst composition may be self-bound (that is without a separate binder) or may also comprise a binder or matrix material that is resistant to the temperatures and other conditions employed in the present process. Where such a binder or matrix material is present, it is preferably substantially free of amorphous alumina, since it is found that the exclusion of a binder containing amorphous alumina reduces external catalytic sites for coke production and hence increases catalyst cycle length.
  • One preferred binder material for the third catalyst composition comprises silica since extrusion with silica ensures that the catalyst has high mesoporosity and hence high activity.
  • the binder or matrix material may be a crystalline molecular sieve material, which may be isostructural with, or have a different structure than, the third molecular sieve.
  • each of the first, second and third catalyst compositions includes a silica binder.
  • the third catalyst composition contains a binder or matrix material
  • the latter may be present in an amount ranging from 5 to 95 wt.% of the total catalyst composition.
  • the matrix is present in an amount ranging from 10 to 60 wt.%, of the total catalyst composition.
  • the third catalyst composition may be extruded into particles of any desired shape before being loaded into the first catalyst bed.
  • Suitable particle configurations for achieving such a surface to volume ratio include grooved cylindrical extrudates and hollow or solid polylobal extrudates, such as quadrulobal extrudates.
  • the third catalyst composition comprises up to 25 wt% of the total weight of the first, second and third catalysts compositions.
  • the third catalyst may comprise from 5 wt% to 25 wt%, such as from 5 wt% to 15 wt% of the total weight of the first, second and third catalyst compositions.
  • the third catalyst bed is maintained under conditions effective to crack non-aromatic cyclic hydrocarbons in the effluent from the second catalyst bed.
  • Suitable conditions for operation of the third catalyst bed comprise a temperature in the range of about 100 to about 800°C, preferably about 300 to about 500°C, a pressure in the range of about 790 to about 7000 kPa-a, preferably about 2170 to 3000 kPa-a, a H2:HC molar ratio in the range of about 0.01 to about 20, preferably about 1 to about 10, and a WHSV in the range of about 0.01 to about 100 hr "1 , preferably about 1 to about 50 hr "1 .
  • a silica-bound PtZSM-5 catalyst (50 wt% SiO 2 /50 wt% ZSM-5) was prepared from ZSM-5 having an average crystal size of 0.02-0.05 micron.
  • the catalyst contained 0.05 wt% platinum and had an alpha value of 170.
  • the resultant catalyst was used to convert a heavy aromatics stream comprising 85 wt% of a C9+ aromatics feed blended with 7 wt% benzene and 8 wt% toluene.
  • Reaction conditions included an initial temperature of 407°C, WHSV of 15, a pressure of 350 psia (2413 kPa) and a hydrogen to hydrocarbon molar ratio of 2.
  • the catalyst was de-edged by contacting with the feed at a temperature of 430°C, WHSV of 15, a pressure of 350 psia (2413 kPa) and a hydrogen to hydrocarbon molar ratio of 1 for 3 days.
  • a catalyst aging study was conducted by measuring the normalized average reactor temperature (ART) required to achieve 40% conversion of the C9 and C10 aromatics in the feed over a period of 40 days. The results are shown in FIG. 1. The ethyl-aromatic conversion activity of the catalyst system was also measured during the 40 day aging study and the results are shown in FIG. 2.
  • Example 1 The process of Example 1 was repeated but with an alumina bound PtZSM-5 catalyst (50 wt% AI2O3/5O wt% ZSM-5). Again the ZSM-5 had an average crystal size of 0.02-0.05 micron and the catalyst contained 0.05 wt% platinum. The alpha value of the catalyst was 300. The results of the aging study are again shown in FIGs 1 and 2 from which it will be seen that the silica bound catalyst exhibited reduced aging, lower coke make and higher dealkylation activity than the alumina bound catalyst system.
  • compositions, an element or a group of elements are preceded with the transitional phrase "comprising,” it is understood that we also contemplate the same composition or group of elements with transitional phrases “consisting essentially of,” “consisting of,” “selected from the group of consisting of,” or “is” preceding the recitation of the composition, element, or elements and vice versa.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Catalysts (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

La présente invention concerne un procédé de production de xylène qui consiste à mettre en contact une première charge d'alimentation comprenant des hydrocarbures aromatiques en C9+, au moins un hydrocarbure aromatique en C6-C7 et de l'hydrogène avec une première composition de catalyseur pour désalkyler au moins une partie des hydrocarbures aromatiques en C9+ contenant des groupes alkyle en C2+ et pour saturer les oléfines résultantes en C2+ pour produire une seconde charge d'alimentation. La seconde charge d'alimentation est ensuite mise en contact avec une seconde composition de catalyseur sous des conditions efficaces pour transalkyler au moins une partie des hydrocarbures aromatiques en C9+ avec au moins une partie de l'hydrocarbure aromatique en C6-C7 pour produire un premier produit comprenant du xylène. Chacune des première et deuxième compositions de catalyseur est sensiblement exempte d'alumine amorphe.
PCT/US2015/031671 2014-06-04 2015-05-20 Transalkylation de charges d'hydrocarbures aromatiques lourds WO2015187363A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US201462007556P 2014-06-04 2014-06-04
US62/007,556 2014-06-04
EP14177010 2014-07-15
EP14177010.7 2014-07-15

Publications (1)

Publication Number Publication Date
WO2015187363A1 true WO2015187363A1 (fr) 2015-12-10

Family

ID=51176255

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2015/031671 WO2015187363A1 (fr) 2014-06-04 2015-05-20 Transalkylation de charges d'hydrocarbures aromatiques lourds

Country Status (1)

Country Link
WO (1) WO2015187363A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107952470A (zh) * 2016-10-14 2018-04-24 中国石油化工股份有限公司 复合分子筛的合成方法及应用
CN109647329A (zh) * 2019-01-29 2019-04-19 大连理工大学盘锦产业技术研究院 一种无粘结剂复合分子筛制备方法及其在油品吸附脱硫中的应用

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5942651A (en) * 1997-06-13 1999-08-24 Mobile Oil Corporation Process for converting C9 + aromatic hydrocarbons to lighter aromatic products by transalkylation in the prescence of two zeolite-containing catalysts
US7485763B2 (en) * 2002-11-14 2009-02-03 Exxonmobil Chemical Patents Inc. Using a catalyst having two different zeolites for transalkylation of a C9+ aromatic feed
US7663010B2 (en) * 2007-10-31 2010-02-16 Exxonmobil Chemical Patents Inc. Heavy aromatics processing catalyst and process of using the same
US20110190560A1 (en) * 2010-02-03 2011-08-04 Chunshe Cao Transalkylation of Heavy Aromatic Hydrocarbon Feedstocks
US8183424B2 (en) * 2010-02-03 2012-05-22 Exxonmobil Chemical Patents Inc. Transalkylation of heavy aromatic hydrocarbon feedstocks

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5942651A (en) * 1997-06-13 1999-08-24 Mobile Oil Corporation Process for converting C9 + aromatic hydrocarbons to lighter aromatic products by transalkylation in the prescence of two zeolite-containing catalysts
US7485763B2 (en) * 2002-11-14 2009-02-03 Exxonmobil Chemical Patents Inc. Using a catalyst having two different zeolites for transalkylation of a C9+ aromatic feed
US7663010B2 (en) * 2007-10-31 2010-02-16 Exxonmobil Chemical Patents Inc. Heavy aromatics processing catalyst and process of using the same
US20110190560A1 (en) * 2010-02-03 2011-08-04 Chunshe Cao Transalkylation of Heavy Aromatic Hydrocarbon Feedstocks
US8183424B2 (en) * 2010-02-03 2012-05-22 Exxonmobil Chemical Patents Inc. Transalkylation of heavy aromatic hydrocarbon feedstocks

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107952470A (zh) * 2016-10-14 2018-04-24 中国石油化工股份有限公司 复合分子筛的合成方法及应用
CN109647329A (zh) * 2019-01-29 2019-04-19 大连理工大学盘锦产业技术研究院 一种无粘结剂复合分子筛制备方法及其在油品吸附脱硫中的应用

Similar Documents

Publication Publication Date Title
US8183424B2 (en) Transalkylation of heavy aromatic hydrocarbon feedstocks
US8071828B2 (en) Transalkylation of heavy aromatic hydrocarbon feedstocks
CA2702423C (fr) Catalyseur de traitement d'aromatiques lourds et son procede d'utilisation
US20150353447A1 (en) Transalkylation of Heavy Aromatic Hydrocarbon Feedstocks
US20190359542A1 (en) Transalkylation of Heavy Aromatic Hydrocarbons
EP0808299A4 (fr) Traitement d'aromatiques lourds
US8163966B2 (en) Aromatics processing catalyst system
US20210230083A1 (en) Dealkylation and Transalkylation of Heavy Aromatic Hydrocarbons
US20150025283A1 (en) Process and Catalyst for C9+ Aromatics Conversion
US20160221897A1 (en) Transalkylation of Heavy Aromatic Hydrocarbon Feedstocks
WO2013169465A1 (fr) Procédé de production de xylènes
US10781149B2 (en) Transalkylation process
WO2015187363A1 (fr) Transalkylation de charges d'hydrocarbures aromatiques lourds
US11001544B2 (en) Transalkyation processes in the presence of sulfolane
JP2023523928A (ja) 重質芳香族化合物の、低環飽和のより軽質の芳香族化合物への変換、及び炭化水素クラッキング

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 15803097

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 15803097

Country of ref document: EP

Kind code of ref document: A1