WO2009073263A1 - Regeneration process for a c8 alkylaromatic isomerization catalyst - Google Patents

Regeneration process for a c8 alkylaromatic isomerization catalyst Download PDF

Info

Publication number
WO2009073263A1
WO2009073263A1 PCT/US2008/077592 US2008077592W WO2009073263A1 WO 2009073263 A1 WO2009073263 A1 WO 2009073263A1 US 2008077592 W US2008077592 W US 2008077592W WO 2009073263 A1 WO2009073263 A1 WO 2009073263A1
Authority
WO
WIPO (PCT)
Prior art keywords
catalyst
temperature
isomerization catalyst
regeneration process
weight
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/US2008/077592
Other languages
French (fr)
Inventor
Paula L. Bogdan
Gregory F. Maher
John E. Bauer
Patrick C. Whitchurch
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Honeywell UOP LLC
Original Assignee
UOP LLC
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 UOP LLC filed Critical UOP LLC
Publication of WO2009073263A1 publication Critical patent/WO2009073263A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J38/00—Regeneration or reactivation of catalysts, in general
    • B01J38/04—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst
    • B01J38/12—Treating with free oxygen-containing gas
    • B01J38/20—Plural distinct oxidation stages
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/70—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65
    • B01J29/72—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65 containing iron group metals, noble metals or copper
    • B01J29/74—Noble metals
    • B01J29/7469—MTW-type, e.g. ZSM-12, NU-13, TPZ-12 or Theta-3
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/90—Regeneration or reactivation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/0009—Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J38/00—Regeneration or reactivation of catalysts, in general
    • B01J38/04—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst
    • B01J38/12—Treating with free oxygen-containing gas
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J38/00—Regeneration or reactivation of catalysts, in general
    • B01J38/04—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst
    • B01J38/42—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst using halogen-containing material
    • B01J38/44—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst using halogen-containing material and adding simultaneously or subsequently free oxygen; using oxyhalogen compound
    • 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
    • C07C5/22—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by isomerisation
    • C07C5/27—Rearrangement of carbon atoms in the hydrocarbon skeleton
    • C07C5/2702—Catalytic processes not covered by C07C5/2732 - C07C5/31; Catalytic processes covered by both C07C5/2732 and C07C5/277 simultaneously
    • C07C5/2708—Catalytic processes not covered by C07C5/2732 - C07C5/31; Catalytic processes covered by both C07C5/2732 and C07C5/277 simultaneously with crystalline alumino-silicates, e.g. molecular sieves
    • 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
    • C07C5/22—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by isomerisation
    • C07C5/27—Rearrangement of carbon atoms in the hydrocarbon skeleton
    • C07C5/2702—Catalytic processes not covered by C07C5/2732 - C07C5/31; Catalytic processes covered by both C07C5/2732 and C07C5/277 simultaneously
    • C07C5/2724—Catalytic processes not covered by C07C5/2732 - C07C5/31; Catalytic processes covered by both C07C5/2732 and C07C5/277 simultaneously with metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/30—After treatment, characterised by the means used
    • B01J2229/42—Addition of matrix or binder particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/18—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type
    • B01J29/20—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type containing iron group metals, noble metals or copper
    • B01J29/22—Noble metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
    • B01J29/42—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively containing iron group metals, noble metals or copper
    • B01J29/44—Noble metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/0072—Preparation of particles, e.g. dispersion of droplets in an oil bath
    • 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
    • C07C2521/02—Boron or aluminium; Oxides or hydroxides thereof
    • C07C2521/04—Alumina
    • 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
    • C07C2529/18—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type
    • 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
    • C07C2529/18—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type
    • C07C2529/20—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type containing iron group metals, noble metals or copper
    • C07C2529/22—Noble metals
    • 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
    • C07C2529/70—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups C07C2529/08 - C07C2529/65
    • 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
    • C07C2529/70—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups C07C2529/08 - C07C2529/65
    • C07C2529/72—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups C07C2529/08 - C07C2529/65 containing iron group metals, noble metals or copper
    • C07C2529/74—Noble metals
    • 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
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
    • 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
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/584—Recycling of catalysts

Definitions

  • the field of this invention generally relates to a regeneration process for a catalyst for a C8 aromatic isomerization process.
  • Xylenes such as para-xylene, meta-xylene and ortho-xylene
  • xylenes from catalytic reforming or other sources generally do not match demand proportions as chemical intermediates, and further comprise ethylbenzene, which can be difficult to separate or to convert.
  • para-xylene is a major chemical intermediate with significant demand, but amounts to only 20% to 25%, by weight, of a typical C8 aromatic stream.
  • Adjustment of an isomer ratio to demand can be effected by combining xylene-isomer recovery, such as adsorption for para-xylene recovery, with isomerization to yield an additional quantity of the desired isomer.
  • isomerization converts a non- equilibrium mixture of the xylene isomers that is lean in the desired xylene isomer to a mixture approaching equilibrium concentrations.
  • the process involves heating the catalyst in an oxidizing gas to burn carbonaceous material deposited on the catalyst.
  • a regenerated catalyst having the same activity as fresh catalyst.
  • this goal can be elusive. If conditions are too severe, the regenerated catalyst may have excessive xylene isomerization activity and generate excessive byproducts, such as toluene and C9 aromatic compounds. If conditions are insufficient, the regenerated catalyst may be ineffective.
  • regeneration can be challenging due to the presence of steam at elevated temperatures that can result in hydrothermal damage to the zeolite structure impacting the number, strength and accessibility of acid sites. [0004] Accordingly, it is desirable to regenerate a C8 alkylaromatic isomerization catalyst to the desired activity after regeneration.
  • One exemplary embodiment can be a regeneration process for a C8 alkylaromatic isomerization catalyst.
  • the process can include: contacting the C8 alkylaromatic isomerization catalyst with a first gas stream including an oxidizing gas at a first stage for a first time period and a first temperature effective to remove at least a portion of a carbonaceous material from the C8 alkylaromatic isomerization catalyst; and contacting the C 8 alkylaromatic isomerization catalyst with a second gas stream including the oxidizing gas at a second stage for a second time period and a second temperature effective to remove another portion of the carbonaceous material from the C 8 alkylaromatic isomerization catalyst.
  • the C8 alkylaromatic isomerization catalyst can include: 1% to 90%, by weight, of a molecular sieve where the molecular sieve can include at least one of an MTW zeolite, an MFI zeolite, a mordenite zeolite and an ATO non- zeolite sieve, where each zeolite may have a silica to alumina mole ratio less than 45:1; 10% to 99%, by weight, of a binder; and
  • Another exemplary embodiment can be a regeneration process for a C8 alkylaromatic isomerization catalyst.
  • the process can include: contacting the C8 alkylaromatic isomerization catalyst with a first gas stream including an oxidizing gas at a first stage at a temperature of 245 to 500 0 C. effective to remove at least a portion of the carbonaceous material from the C 8 alkylaromatic isomerization catalyst; contacting the C8 alkylaromatic isomerization catalyst with a second gas stream including the oxidizing gas at a second stage at a temperature of 350 to 500° C.
  • the C8 alkylaromatic isomerization catalyst can include:
  • each zeolite may have a silica to alumina mole ratio less than 45:1;
  • a further exemplary embodiment is a regeneration process for a C8 alkylaromatic isomerization catalyst.
  • the process can include: contacting the C 8 alkylaromatic isomerization catalyst with a first gas stream including an oxidizing gas at a first stage at a temperature of 245 to 500 0 C. effective to remove at least a portion of a carbonaceous material from the C8 alkylaromatic isomerization catalyst; contacting the C8 alkylaromatic isomerization catalyst with a second gas stream including the oxidizing gas at a second stage at a temperature of 350 to 500 0 C. effective to remove another portion of the carbonaceous material from the C8 alkylaromatic isomerization catalyst; reducing the C8 alkylaromatic isomerization catalyst; and sulfiding the C8 alkylaromatic isomerization catalyst.
  • the C8 alkylaromatic isomerization catalyst may include:
  • each zeolite may have a silica to alumina mole ratio less than 45:1; 10% to 99%, by weight, of a binder; and
  • zone can refer to an area including one or more equipment items and/or one or more sub-zones.
  • Equipment items can include one or more reactors or reactor vessels, heaters, separators, exchangers, pipes, pumps, compressors, and controllers. Additionally, an equipment item, such as a reactor or vessel, can further include one or more zones or sub-zones.
  • the term "stream” can be a stream including various hydrocarbon molecules, such as straight-chain, branched, or cyclic alkanes, alkenes, alkadienes, and alkynes, and optionally other substances, such as gases, e.g., hydrogen, or impurities, such as heavy metals.
  • the stream can also include aromatic and non-aromatic hydrocarbons.
  • hydrocarbon molecules may be abbreviated Cl, C2, C3 . . . Cn where "n” represents the number of carbon atoms in the hydrocarbon molecule.
  • aromatic can mean a group containing one or more rings of unsaturated cyclic carbon radicals where one or more of the carbon radicals can be replaced by one or more non-carbon radicals.
  • An exemplary aromatic compound is benzene having a C6 ring containing three double bonds.
  • Other exemplary aromatic compounds can include para-xylene, ortho-xylene, meta-xylene and ethylbenzene.
  • support generally means a molecular sieve that has been combined with a binder before the addition of one or more additional catalytically active components, such as a noble metal, or subjected to a subsequent process such as reducing or sulfiding.
  • the regeneration process disclosed herein can provide a low inlet and catalyst bed temperature during the primary carbon removal stage.
  • low water concentration can aid the catalyst regeneration.
  • sufficient yet regulated halogen injection can maintain the dispersion of at least one noble metal while limiting residual halogen at the completion of the procedure.
  • 0.05% to 0.5 %, by weight, carbon may remain on the catalyst after the regeneration, based on the weight of the catalyst.
  • the amount of carbon on the catalyst can be determined by UOP Method 703-98.
  • the regeneration process can be utilized for a variety of catalysts.
  • a typical catalyst regenerated by the process disclosed herein can include a zeolite or a non-zeolite molecular sieve.
  • the molecular sieve can be at least one of an MTW zeolite, an MFI zeolite, a mordenite zeolite, and an ATO non- zeolite sieve.
  • MTW zeolites are disclosed in US 3,856,871, an exemplary mordenite zeolite is disclosed in US 6,465,705 Bl, and an exemplary ATO non- zeolite sieve, such as an MgAPSO-31 non- zeolite sieve, is disclosed in US 4,758,419.
  • the zeolites can have a silica to alumina mole ratio less than 45:1, desirably from 20:1 to 40:1.
  • the MgAPSO-31 non-zeolite sieve can have an Si/ Al 2 mole ratio of 0.01 :1 to 0.5:1, preferably 0.01 :1 to 0.03: 1.
  • the molecular sieve can be composited with a binder for forming a catalyst support.
  • the proportion of the molecular sieve in the catalyst is 1 to 90%, by weight, desirably 2 to 20%, by weight, with the remainder optionally being one or more metal and other components along with a binder, as discussed herein.
  • the binder is a porous, adsorptive support having a surface area of 25 to 500 m 2 /g.
  • the binder can be: (1) a refractory inorganic oxide such as an alumina, a titania, a zirconia, a chromia, a zinc oxide, a magnesia, a thoria, a boria, a silica-alumina, a silica-magnesia, a chromia-alumina, an alumina-boria, a silica-zirconia, or a phosphorus- alumina; (2) a ceramic, a porcelain, or a bauxite; (3) a silica or silica gel, a silicon carbide, a synthetically prepared or naturally occurring clay or silicate, optionally acid treated, as an example, an attapulgite clay, a diatomaceous earth, a fuller's earth, a kaolin, or a kieselguhr; (4) a naturally occurring or synthetically prepared crystalline zeolitic aluminos
  • a desired refractory inorganic oxide can be alumina.
  • a suitable alumina material is a crystalline alumina known as the gamma-, eta-, or theta-alumina, with gamma- or eta- alumina being preferred.
  • the catalyst can be an extrudate.
  • the extrusion initially involves mixing of the molecular sieve with optionally the binder and a suitable peptizing agent to form a homogeneous dough or thick paste having the correct moisture content to allow for the formation of an extrudate with acceptable integrity to withstand direct calcination.
  • Extrudability may be determined from an analysis of the moisture content of the dough, with a moisture content in the range of from 30% to 70%, by weight, being preferred.
  • the dough may then be extruded through a die pierced with multiple holes and the spaghetti-shaped extrudate can be cut to form particles in accordance with known techniques.
  • a multitude of different extrudate shapes is possible, including a cylinder, cloverleaf, dumbbell, and symmetrical and asymmetrical polylobates.
  • the dough or extrudate may be shaped to any desired form, such as a sphere, by, e.g., marumerization that can entail one or more moving plates or compressing the dough or extrudate into molds.
  • An alternative shape of the catalyst may be a sphere continuously manufactured by a well-known oil drop method.
  • preparation of alumina-bound spheres involves dropping a mixture of molecular sieve, alsol, and gelling agent into an oil bath maintained at elevated temperatures.
  • gelling agents that may be used in this process include hexamethylene tetraamine, urea, and mixtures thereof.
  • the gelling agents can release ammonia at the elevated temperatures which sets or converts the hydrosol spheres into hydrogel spheres.
  • the spheres may be then withdrawn from the oil bath and typically subjected to specific aging treatments in oil and an ammonia solution to further improve their physical characteristics.
  • One exemplary oil dropping method is disclosed in US 2,620,314.
  • the resulting composite is then washed and dried at a relatively low temperature of 50 to 200 0 C. and subjected to a calcination procedure at a temperature of 450 to 700 0 C. for a period of 1 to 20 hours.
  • the catalyst also includes a noble metal, including one or more elements of platinum, palladium, rhodium, ruthenium, osmium, and indium.
  • the preferred noble metal is platinum.
  • the noble metal may exist within the catalyst as a compound such as an oxide, a sulfide, a halide, or an oxysulfide; as an elemental metal; or as a combination with one or more other ingredients of the catalyst.
  • the noble metal exists in a reduced state as an elemental metal.
  • the noble metal may be present in the final catalyst in any catalytically effective amount, typically the noble metal will comprise 0.01 to 2%, preferably 0.05 to 1%, by weight of the final catalyst, calculated on an elemental basis.
  • An IUPAC 14 metal may also be incorporated into the catalyst.
  • germanium and tin are preferred.
  • the IUPAC 14 metal may be present as an elemental metal; as a chemical compound such as an oxide, a sulfide, a halide, or an oxychloride; or as a physical or chemical combination with the porous carrier material and/or other components of the catalyst.
  • a substantial portion of the IUPAC 14 metal exists in a finished catalyst in an oxidation state above that of the elemental metal.
  • the IUPAC 14 metal is present in an amount of 0.01% to 5%, by weight, preferably 0.1% to 2%, by weight, calculated on an elemental basis.
  • the noble metal and IUPAC 14 metal may be incorporated into the catalyst in any suitable manner, such as disclosed in US 2005/0277796.
  • the catalyst may contain other additional metal components, such as rhenium, cobalt, nickel, indium, gallium, zinc, uranium, dysprosium, thallium, or a mixture thereof. A catalytically effective amount of such a metal component may be incorporated into the catalyst by any means known in the art to effect a homogeneous or stratified distribution.
  • the catalyst may contain a halogen component, such as fluorine, chlorine, bromine, iodine, or a mixture thereof, with chlorine being preferred. Desirably, however, the catalyst contains no added halogen other than that associated with other catalyst components.
  • the elemental analysis of the catalyst components can be determined by Inductively Coupled Plasma (ICP) analysis.
  • the catalyst is dried, calcined, and reduced according to any suitable method, including those disclosed in US 2005/0277796. In some cases, the resulting reduced catalyst may also be subjected to presulftding with, for example, neat H 2 S at room temperature to incorporate in the catalyst composite from 0.05 to 1.0%, by weight, sulfur, calculated on an elemental basis.
  • the catalyst can be included in a zone to isomerize alkylaromatic hydrocarbons, for example, those of the general formula C 6 H( 6-n )R n , where n is an integer from 2 - 5 and R is CH 3 , C 2 H 5 , C 3 H 7 , or C 4 H 9 , in any combination including all the isomers thereof.
  • Suitable alkylaromatic hydrocarbons may include, for example, an ortho-xylene, a meta-xylene, a para-xylene, an ethylbenzene, an ethyltoluene, a tri-methylbenzene, a di-ethylbenzene, a tri- ethyl-benzene, a methylpropylbenzene, an ethylpropylbenzene, a di-isopropylbenzene, or a mixture thereof.
  • One desired application of the catalyst is the isomerization of a C8 aromatic mixture containing ethylbenzene and one or more xylenes.
  • the mixture has an ethylbenzene content of 1% to 50%, by weight, an ortho-xylene content of 0% to 35%, by weight, a meta-xylene content of 20% to 95%, by weight, and a para-xylene content of 0% to 30%, by weight.
  • a non-equilibrium mixture of at least one C 8 aromatic isomer is present in a concentration that can differ substantially from the equilibrium concentration at isomerization conditions.
  • the non-equilibrium mixture is prepared by removal of para-, ortho- and/or meta-xylene from a fresh C 8 aromatic mixture obtained from an aromatic production process.
  • the alkylaromatic hydrocarbons may be found in an appropriate fraction from various refinery petroleum streams, e.g., as individual components or as certain boiling-range fractions obtained by the selective fractionation and distillation of catalytically cracked or reformed hydrocarbons. Concentration of the isomerizable aromatic hydrocarbons may be optional.
  • a C8 aromatics feed may contain nonaromatic hydrocarbons, i.e., naphthenes and paraffins, in an amount up to 30%, by weight.
  • the isomerizable hydrocarbons consist essentially of aromatics.
  • the regeneration process generally entails one or more stages, preferably two stages, of contacting the catalyst with an oxidizing gas.
  • the oxidizing gas is air.
  • the contacting for both stages can be conducted in an atmosphere including an inert gas, such as nitrogen, and the oxidizing gas.
  • the atmosphere can generally include 1 to 20 mole percent, preferably 2 to 15 mole percent, of oxygen.
  • the oxygen content can be varied during the stage depending on a temperature of an exotherm.
  • the stages can be conducted in the presence of water or steam, such as up to 5.0 mole percent, preferably 2.5 mole percent, steam at 101.325 kPa.
  • water is usually undesired component in a regeneration process, typically a commercial unit may have a partial pressure of, e.g., 3 kPa, of water in a pressurized burn.
  • the stages can also be conducted in the presence of halogen, such as chloride.
  • the halogen can be present in amount of 10:1 to 250:1 wate ⁇ Cl mole ratio, preferably 40:1 to 225:1.
  • the first stage oxidation can be conducted at a temperature of 245 to 500 0 C, desirably 245 to 400° C, and optimally 270 to 390° C. for a selected first time period of 0.5 to 3 days, preferably 0.5 to 1.5 days.
  • the second stage oxidation can be conducted at temperature of 350 to 500° C, preferably 350 to 400° C. for a selected second time period of 0.5 to 3 days, preferably 0.5 to 1.5 days.
  • the temperature and/or time period of the first stage oxidation is different than the respective temperature and/or time period of the second stage oxidation.
  • the initial temperature of the first stage oxidation is lower than the second stage oxidation.
  • the time periods of the first and second oxidation stages are of sufficient length so no significant amount of oxidizing gas is reacted at the end of the respective stage.
  • the oxidized catalyst can be contacted with a reducing agent, such as hydrogen, in an atmosphere including up to 100 mole percent hydrogen.
  • the conditions can include a temperature of 200 to 65O 0 C, preferably 400 to 450 0 C
  • the catalyst can be cold sulfided with neat H 2 S at room temperature to incorporate in the catalyst from 0.05 to 1.0%, by weight, sulfur calculated on an elemental basis to replace sulfur on the platinum.
  • such a C 8 aromatic mixture can be contacted with the regenerated catalyst in an alkylaromatic hydrocarbon isomerization zone, such as disclosed in US 2005/0277796, for isomerizing, e.g., ethylbenzene into one or more xylenes.
  • an alkylaromatic hydrocarbon isomerization zone such as disclosed in US 2005/0277796, for isomerizing, e.g., ethylbenzene into one or more xylenes.
  • An oil-dropped sphere catalyst contains 0.32%, by weight, platinum; 5%, by weight, MTW zeolite; and the remainder, by weight, alumina. This catalyst is subjected to an isomerization process to accumulate 2.5%, by weight, carbon.
  • the spent catalyst is sandwiched between an effective amount of a top layer of alumina-supported platinum catalyst spheres and a bottom layer of gamma-alumina spheres. The top layer catalyzes HCl and air to chlorine gas and water that may pass through the spent catalyst.
  • the spent catalyst is regenerated with two burn stages. [0039] The first burn stage is conducted at an initial temperature of 355°C.
  • the atmosphere can contain 2%, by mole, oxygen for the first 24 hours and 15%, by mole, oxygen for the last 4 hours.
  • the maximum bed temperature is 396°C.
  • the air flow is stopped if the exotherm exceeds a delta of 35 0 C. (a temperature of 390°C.) and restarted once the temperature falls to a delta of 13°C. (a temperature of 368 0 C).
  • the bed is purged with nitrogen at 1150 cc/minute for 15 minutes at room temperature. Next, the bed is ramped at 2° C./minute to 150° C.
  • Air at 125 cc/minute and a 0.25 M HCl solution at a delivery rate of 1.4 cc/hour can be introduced with the air introduction being stopped and started depending on the exotherm temperature, as discussed above. These parameters are maintained for 24 hours. Afterwards, the air is increased to 920 cc/minute and nitrogen is decreased to 355 cc/minute and held for 3.5 hours. Next, the HCl injection is stopped and the temperature is maintained at 355° C. for 0.5 hours. That being done, the catalyst is cooled with air and nitrogen to room temperature.
  • the second burn stage is conducted at an initial temperature of 37O 0 C. for 28 hours in an atmosphere containing 2.4%, by mole, steam at 101.325 kPa and a water: chloride mole ratio of 222: 1.
  • the atmosphere can contain 2%, by mole, oxygen for the first 24 hours and 15%, by mole, oxygen for the last 4 hours.
  • the air flow is stopped if the exotherm exceeds a delta of 35°C. (a temperature of 405 0 C.) and restarted once the temperature falls to a delta of 13 0 C. (a temperature of 383°C).
  • the bed is purged, if desired, with nitrogen at 1150 cc/minute for 15 minutes at room temperature.
  • the bed is ramped at 2° C./minute to 150° C. and held for 0.5 hours at that temperature.
  • the temperature is ramped at 2° C./minute to 370° C. and held to stabilize the temperature before introducing air.
  • Air at 125 cc/minute and a 0.25 M HCl solution at a delivery rate of 1.4 cc/hour can be introduced with the air introduction being stopped and started depending on the exotherm temperature, as discussed above. These parameters are maintained for 24 hours.
  • the air is increased to 920 cc/minute and nitrogen is decreased to 355 cc/minute and held for 3.5 hours.
  • the HCl injection is stopped and the temperature is maintained at 355° C. for 0.5 hours. That being done, the catalyst is cooled with air and nitrogen to room temperature.
  • the catalyst is reduced in an atmosphere of 100%, by mole, hydrogen for two hours at 425° C.
  • the catalyst has 0.5%, by weight, carbon remaining as measured after reduction.
  • the catalyst is cold-sulfided to 0.05%, by weight, sulfur.
  • WHSV weight hourly space velocity
  • reaction severity and temperature in a screening evaluation the regenerated catalyst is 20% less active for isomerizing than fresh catalyst. This lower isomerization activity is unexpected because xylene isomerization activity generally increases after regeneration.
  • the ethylbenzene isomerization activity and C8 ring loss are substantially the same as fresh catalyst.
  • C8 ring loss is the loss of C8 rings, in mole or weight percent, that can be converted into a desired C8 aromatic. This example suggests that the milder conditions and/or presence of a higher residual carbon level on the catalyst can prevent the increased activity that typically occurs.
  • a trilobe extrudate catalyst contains 0.3%, by weight, platinum; 8%, by weight, MTW zeolite; and the remainder, by weight, alumina. This catalyst is subjected to an isomerization process to accumulate 2.9%, by weight, carbon.
  • the spent catalyst is sandwiched between a top layer of an effective amount of alumina-supported platinum catalyst spheres and a bottom layer of gamma-alumina spheres.
  • the spent catalyst is regenerated with two burn stages.
  • the first burn stage is conducted at an initial temperature of 355°C. for 26 to 28 hours in an atmosphere containing 2.4%, by mole, steam at 101.325 kPa and a water: chloride mole ratio of 40: 1 ,
  • the atmosphere can contain 2%, by mole, oxygen for the first 24 hours and 15%, by mole, oxygen for the last 4 hours.
  • the maximum bed temperature is 384°C.
  • the air flow is stopped if the exotherm exceeds a delta of 15°C.
  • the bed is purged with nitrogen at 1150 cc/minute for 15 minutes at room temperature.
  • the bed is ramped at 2° C./minute to 150° C. and held for 0.5 hours at that temperature.
  • the temperature is ramped at 2° C./minute to 355° C. and held to stabilize the temperature before introducing air. Air at 125 cc/minute and a 1.4 M
  • HCl solution at a delivery rate of 1.4 cc/hour can be introduced with the air introduction being stopped and started depending on the exotherm temperature, as discussed above. These parameters are maintained for 22 to 24 hours. Afterwards, the air is increased to 920 cc/minute and nitrogen is decreased to 355 cc/minute and held for 3.5 hours. Next, the HCl injection is stopped and the temperature is maintained at 355° C. for 0.5 hours. That being done, the catalyst is cooled with air and nitrogen to room temperature. [O049] The second burn stage is conducted at an initial temperature of 370 0 C. for 28 hours in an atmosphere containing 2.4%, by mole, steam at 101.325 kPa and a water.chloride mole ratio of 222:1.
  • the atmosphere can contain 2%, by mole, oxygen for the first 24 hours and 15%, by mole, oxygen for the last 4 hours.
  • the maximum bed temperature is 381°C.
  • the air flow is stopped if the exotherm exceeds a delta of 15 0 C. (a temperature of 385 0 C.) and restarted once the temperature falls to a delta of 7°C. (a temperature of 377°C).
  • the bed is purged, if desired, with nitrogen at 1150 cc/minute for 15 minutes at room temperature. Next, the bed is ramped at 2° C./minute to 150° C. and held for 0.5 hours at that temperature. Afterwards, the temperature is ramped at 2° C./minute to 370° C.
  • Air at 125 cc/minute and a 0.25 M HCl solution at a delivery rate of 1.4 cc/hour can be introduced with the air introduction being stopped and started depending on the exotherm temperature, as discussed above. These parameters are maintained for 24 hours. Afterwards, the air is increased to 920 cc/minute and nitrogen is decreased to 355 cc/minute and held for 3.5 hours. Next, the HCl injection is stopped and the temperature is maintained at 355° C. for 0.5 hours. That being done, the catalyst is cooled with air and nitrogen to room temperature. The catalyst has 0.25%, by weight, carbon remaining as measured after oxidation.
  • the catalyst is reduced in an atmosphere of 100%, by mole, hydrogen for two hours at 425° C.
  • the catalyst is cold-sulfided to 0.05%, by weight, sulfur.
  • a trilobe extrudate catalyst contains 0.3%, by weight, platinum; 5%, by weight, MTW zeolite; and the remainder, by weight, alumina. This catalyst is divided into two portions. The first portion accounting for 25% of the total catalyst weight is subjected to a single isomerization process and regeneration cycle to accumulate 1.1%, by weight, carbon. The second portion accounting for 75% of the total catalyst weight is subjected to a second isomerization process and regeneration cycle, after an initial isomerization process cycle and subsequent regeneration to accumulate 4.1%, by weight, carbon. [O054] The catalyst portions are separated into separate layers in a four-layer regeneration bed.
  • the regeneration bed has a top layer of an effective amount of alumina-supported platinum catalyst spheres, a second layer of the second catalyst portion, a third layer of the first catalyst portion, and a bottom layer of gamma-alumina spheres.
  • Three sheets of quartz wool separate adjacent layers, namely a first sheet is between the top and second layers, a second sheet is between the second and third layers, and a third sheet is between the third and fourth layers.
  • the spent catalyst including the first and second portions is regenerated with two burn stages
  • the first burn stage is conducted at an initial temperature of 355°C. for 28 hours in an atmosphere containing 2.4%, by mole, steam at 101.325 kPa and a waterxhloride mole ratio of 40: 1.
  • the atmosphere can contain 2%, by mole, oxygen for the first 24 hours and 15%, by mole, oxygen for the last 4 hours.
  • the maximum bed temperature is 384 0 C.
  • the air flow is stopped if the exotherm exceeds a delta of 15 0 C. (a temperature of 370 0 C.) and restarted once the temperature falls to a delta of 7°C. (a temperature of 362°C).
  • the bed is purged with nitrogen at 1150 cc/minute for 15 minutes at room temperature.
  • the bed is ramped at 2° C./minute to 150° C. and held for 0.5 hours at that temperature.
  • the temperature is ramped at 2° C./minute to 355° C. and held to stabilize the temperature before introducing air.
  • Air at 125 cc/minute and a 1.4 M HCl solution at a delivery rate of 1.4 cc/hour can be introduced with the air introduction being stopped and started depending on the exotherm temperature, as discussed above. These parameters are maintained for 24 hours.
  • the air is increased to 920 cc/minute and nitrogen is decreased to 355 cc/minute and held for 3.5 hours.
  • the HCl injection is stopped and the temperature is maintained at 355° C. for 0.5 hours. That being done, the catalyst is cooled with air and m ' trogen to room temperature.
  • the second burn stage is conducted at an initial temperature of 370 0 C. for 28 hours in an atmosphere containing 2.4%, by mole, steam at 101.325 kPa and a water: chloride mole ratio of 222: 1.
  • the atmosphere can contain 2%, by mole, oxygen for the first 24 hours and 15%, by mole, oxygen for the last 4 hours.
  • the maximum bed temperature is 377°C.
  • the air flow is stopped if the exotherm exceeds a delta of 15 0 C. (a temperature of 385°C.) and restarted once the temperature falls to a delta of 7°C. (a temperature of 377°C).
  • the bed is purged, if desired, with nitrogen at 1150 cc/minute for 15 minutes at room temperature.
  • the bed is ramped at 2°C./minute to 150 0 C. and held for 0.5 hours at that temperature.
  • the temperature is ramped at 2°C./minute to 370 0 C. and held to stabilize the temperature before introducing air.
  • Air at 125 cc/minute and a 0.25 M HCl solution at a delivery rate of 1.4 cc/hour can be introduced with the air introduction being stopped and started depending on the exotherm temperature, as discussed above. These parameters are maintained for 24 hours, except the delivery of water and HCl solution can be stopped for 12 hours.
  • the air is increased to 920 cc/minute and nitrogen is decreased to 355 cc/minute and held for 3.5 hours.
  • the HCl injection is stopped and the temperature is maintained at 355 0 C. for 0.5 hours. That being done, the catalyst is cooled with air and nitrogen to room temperature.
  • the first portion of catalyst has 0.08%, by weight, carbon and the second portion of catalyst has 0.14%, by weight, carbon remaining as measured after oxidation.
  • the catalyst portions are separately reduced in an atmosphere of 100%, by mole, hydrogen for two hours at 425° C, and cold-sulfided to

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

Abstract

One exemplary embodiment can be a regeneration process for a C8 alkylaromatic isomerization catalyst. The process can include: contacting the C8 alkylaromatic isomerization catalyst with a first gas stream comprising an oxidizing gas at a first stage for a first time period and a first temperature effective to remove at least a portion of a carbonaceous material from the C8 alkylaromatic isomerization catalyst; and contacting the C8 alkylaromatic isomerization catalyst with a second gas stream comprising the oxidizing gas at a second stage for a second time period and a second temperature effective to remove another portion of the carbonaceous material from the C8 alkylaromatic isomerization catalyst.

Description

REGENERATION PROCESS FOR A C8 ALKYLAROMATIC ISOMERIZATION CATALYST
FIELD OF THE INVENTION
[0001] The field of this invention generally relates to a regeneration process for a catalyst for a C8 aromatic isomerization process.
BACKGROUND OF THE INVENTION
[0002] Xylenes, such as para-xylene, meta-xylene and ortho-xylene, can be important intermediates that find wide and varied application in chemical syntheses. However, xylenes from catalytic reforming or other sources generally do not match demand proportions as chemical intermediates, and further comprise ethylbenzene, which can be difficult to separate or to convert. Typically, para-xylene is a major chemical intermediate with significant demand, but amounts to only 20% to 25%, by weight, of a typical C8 aromatic stream. Adjustment of an isomer ratio to demand can be effected by combining xylene-isomer recovery, such as adsorption for para-xylene recovery, with isomerization to yield an additional quantity of the desired isomer. Typically, isomerization converts a non- equilibrium mixture of the xylene isomers that is lean in the desired xylene isomer to a mixture approaching equilibrium concentrations.
[0003] Various catalysts and processes have been developed to effect xylene isomerization. Generally, after a given period of time, the catalyst can become spent and require regeneration. There are many processes that can be utilized to regenerate catalyst.
Typically, the process involves heating the catalyst in an oxidizing gas to burn carbonaceous material deposited on the catalyst. Generally, it is desirable to have a regenerated catalyst having the same activity as fresh catalyst. For some types of catalysts, this goal can be elusive. If conditions are too severe, the regenerated catalyst may have excessive xylene isomerization activity and generate excessive byproducts, such as toluene and C9 aromatic compounds. If conditions are insufficient, the regenerated catalyst may be ineffective. Moreover, regeneration can be challenging due to the presence of steam at elevated temperatures that can result in hydrothermal damage to the zeolite structure impacting the number, strength and accessibility of acid sites. [0004] Accordingly, it is desirable to regenerate a C8 alkylaromatic isomerization catalyst to the desired activity after regeneration.
BRIEF SUMMARY OF THE INVENTION
[0005] One exemplary embodiment can be a regeneration process for a C8 alkylaromatic isomerization catalyst. The process can include: contacting the C8 alkylaromatic isomerization catalyst with a first gas stream including an oxidizing gas at a first stage for a first time period and a first temperature effective to remove at least a portion of a carbonaceous material from the C8 alkylaromatic isomerization catalyst; and contacting the C 8 alkylaromatic isomerization catalyst with a second gas stream including the oxidizing gas at a second stage for a second time period and a second temperature effective to remove another portion of the carbonaceous material from the C 8 alkylaromatic isomerization catalyst.
[O006] The C8 alkylaromatic isomerization catalyst can include: 1% to 90%, by weight, of a molecular sieve where the molecular sieve can include at least one of an MTW zeolite, an MFI zeolite, a mordenite zeolite and an ATO non- zeolite sieve, where each zeolite may have a silica to alumina mole ratio less than 45:1; 10% to 99%, by weight, of a binder; and
0.1% to 2%, by weight, of a noble metal, calculated on an elemental basis. [O007] Another exemplary embodiment can be a regeneration process for a C8 alkylaromatic isomerization catalyst. The process can include: contacting the C8 alkylaromatic isomerization catalyst with a first gas stream including an oxidizing gas at a first stage at a temperature of 245 to 5000C. effective to remove at least a portion of the carbonaceous material from the C 8 alkylaromatic isomerization catalyst; contacting the C8 alkylaromatic isomerization catalyst with a second gas stream including the oxidizing gas at a second stage at a temperature of 350 to 500° C. effective to remove another portion of the carbonaceous material from the C8 alkylaromatic isomerization catalyst; and removing a total amount of at least 75%, by weight, of the carbonaceous material. [0008] The C8 alkylaromatic isomerization catalyst can include:
1% to 90%, by weight, of at least one of an MTW zeolite, an MFI zeolite, a mordenite zeolite, and an MgAPSO-31 non-zeolite molecular sieve, where each zeolite may have a silica to alumina mole ratio less than 45:1;
10% to 99%, by weight, of a binder; and
0.1% to 2%, by weight, of a noble metal, calculated on an elemental basis. [0009] A further exemplary embodiment is a regeneration process for a C8 alkylaromatic isomerization catalyst. The process can include: contacting the C 8 alkylaromatic isomerization catalyst with a first gas stream including an oxidizing gas at a first stage at a temperature of 245 to 5000C. effective to remove at least a portion of a carbonaceous material from the C8 alkylaromatic isomerization catalyst; contacting the C8 alkylaromatic isomerization catalyst with a second gas stream including the oxidizing gas at a second stage at a temperature of 350 to 5000C. effective to remove another portion of the carbonaceous material from the C8 alkylaromatic isomerization catalyst; reducing the C8 alkylaromatic isomerization catalyst; and sulfiding the C8 alkylaromatic isomerization catalyst.
[OOIO] The C8 alkylaromatic isomerization catalyst may include:
1% to 90%, by weight, of at least one of an MTW zeolite, an MFI zeolite, a mordenite zeolite, and an ATO non-zeolite sieve, where each zeolite may have a silica to alumina mole ratio less than 45:1; 10% to 99%, by weight, of a binder; and
0.1% to 2%, by weight, of a noble metal, calculated on an elemental basis. [OO 11] Therefore, a regeneration process of effective severity can provide a regenerated catalyst with an activity similar to fresh catalyst for xylene and ethylbenzene isomerization and C8 ring loss. DEFINITIONS
[OO 12] As used herein, the term "zone" can refer to an area including one or more equipment items and/or one or more sub-zones. Equipment items can include one or more reactors or reactor vessels, heaters, separators, exchangers, pipes, pumps, compressors, and controllers. Additionally, an equipment item, such as a reactor or vessel, can further include one or more zones or sub-zones.
[OO 13] As used herein, the term "stream" can be a stream including various hydrocarbon molecules, such as straight-chain, branched, or cyclic alkanes, alkenes, alkadienes, and alkynes, and optionally other substances, such as gases, e.g., hydrogen, or impurities, such as heavy metals. The stream can also include aromatic and non-aromatic hydrocarbons.
Moreover, the hydrocarbon molecules may be abbreviated Cl, C2, C3 . . . Cn where "n" represents the number of carbon atoms in the hydrocarbon molecule. [OO 14] As used herein, the term "aromatic" can mean a group containing one or more rings of unsaturated cyclic carbon radicals where one or more of the carbon radicals can be replaced by one or more non-carbon radicals. An exemplary aromatic compound is benzene having a C6 ring containing three double bonds. Other exemplary aromatic compounds can include para-xylene, ortho-xylene, meta-xylene and ethylbenzene. Moreover, characterizing a stream or zone as "aromatic" can imply one or more different aromatic compounds comprised in a stream or zone. [OO 15] As used herein, the term "support" generally means a molecular sieve that has been combined with a binder before the addition of one or more additional catalytically active components, such as a noble metal, or subjected to a subsequent process such as reducing or sulfiding.
DETAILED DESCRIPTION OF THE INVENTION [OO 16] The regeneration process disclosed herein can provide a low inlet and catalyst bed temperature during the primary carbon removal stage. In addition, low water concentration can aid the catalyst regeneration. Moreover, sufficient yet regulated halogen injection can maintain the dispersion of at least one noble metal while limiting residual halogen at the completion of the procedure. Desirably, 0.05% to 0.5 %, by weight, carbon may remain on the catalyst after the regeneration, based on the weight of the catalyst. The amount of carbon on the catalyst can be determined by UOP Method 703-98. The regeneration process can be utilized for a variety of catalysts.
[OO 17] A typical catalyst regenerated by the process disclosed herein can include a zeolite or a non-zeolite molecular sieve. The molecular sieve can be at least one of an MTW zeolite, an MFI zeolite, a mordenite zeolite, and an ATO non- zeolite sieve. Exemplary MFI and
MTW zeolites are disclosed in US 3,856,871, an exemplary mordenite zeolite is disclosed in US 6,465,705 Bl, and an exemplary ATO non- zeolite sieve, such as an MgAPSO-31 non- zeolite sieve, is disclosed in US 4,758,419. Desirably, the zeolites can have a silica to alumina mole ratio less than 45:1, desirably from 20:1 to 40:1. Typically, the MgAPSO-31 non-zeolite sieve can have an Si/ Al2 mole ratio of 0.01 :1 to 0.5:1, preferably 0.01 :1 to 0.03: 1. [0018] The molecular sieve can be composited with a binder for forming a catalyst support. Generally, the proportion of the molecular sieve in the catalyst is 1 to 90%, by weight, desirably 2 to 20%, by weight, with the remainder optionally being one or more metal and other components along with a binder, as discussed herein. [OO 19] Generally, the binder is a porous, adsorptive support having a surface area of 25 to 500 m2/g. Desirably, the binder can be: (1) a refractory inorganic oxide such as an alumina, a titania, a zirconia, a chromia, a zinc oxide, a magnesia, a thoria, a boria, a silica-alumina, a silica-magnesia, a chromia-alumina, an alumina-boria, a silica-zirconia, or a phosphorus- alumina; (2) a ceramic, a porcelain, or a bauxite; (3) a silica or silica gel, a silicon carbide, a synthetically prepared or naturally occurring clay or silicate, optionally acid treated, as an example, an attapulgite clay, a diatomaceous earth, a fuller's earth, a kaolin, or a kieselguhr; (4) a naturally occurring or synthetically prepared crystalline zeolitic aluminosilicate, such as FAU, MEL, MFI, MOR, MTW (IUPAC Commission on Zeolite Nomenclature), in hydrogen form or in a form which has been exchanged with one or more metal cations, (5) an aluminophosphate; (6) a spinel such as MgAl2O4, FeAl2O4, ZnAl2O4, CaAl2O4, or another similar compound having a formula MOAl2O3 where M is a metal having a valence of 2; or (7) a combination of materials from one or more of these groups.
[OO2O] A desired refractory inorganic oxide can be alumina. A suitable alumina material is a crystalline alumina known as the gamma-, eta-, or theta-alumina, with gamma- or eta- alumina being preferred. [0021] In one exemplary embodiment, the catalyst can be an extrudate. Generally, the extrusion initially involves mixing of the molecular sieve with optionally the binder and a suitable peptizing agent to form a homogeneous dough or thick paste having the correct moisture content to allow for the formation of an extrudate with acceptable integrity to withstand direct calcination. Extrudability may be determined from an analysis of the moisture content of the dough, with a moisture content in the range of from 30% to 70%, by weight, being preferred. The dough may then be extruded through a die pierced with multiple holes and the spaghetti-shaped extrudate can be cut to form particles in accordance with known techniques. A multitude of different extrudate shapes is possible, including a cylinder, cloverleaf, dumbbell, and symmetrical and asymmetrical polylobates. Furthermore, the dough or extrudate may be shaped to any desired form, such as a sphere, by, e.g., marumerization that can entail one or more moving plates or compressing the dough or extrudate into molds. [O022] An alternative shape of the catalyst may be a sphere continuously manufactured by a well-known oil drop method. Generally, preparation of alumina-bound spheres involves dropping a mixture of molecular sieve, alsol, and gelling agent into an oil bath maintained at elevated temperatures. Examples of gelling agents that may be used in this process include hexamethylene tetraamine, urea, and mixtures thereof. The gelling agents can release ammonia at the elevated temperatures which sets or converts the hydrosol spheres into hydrogel spheres. The spheres may be then withdrawn from the oil bath and typically subjected to specific aging treatments in oil and an ammonia solution to further improve their physical characteristics. One exemplary oil dropping method is disclosed in US 2,620,314. [O023] Preferably, the resulting composite is then washed and dried at a relatively low temperature of 50 to 2000C. and subjected to a calcination procedure at a temperature of 450 to 7000C. for a period of 1 to 20 hours.
[O024] Generally, the catalyst also includes a noble metal, including one or more elements of platinum, palladium, rhodium, ruthenium, osmium, and indium. The preferred noble metal is platinum. The noble metal may exist within the catalyst as a compound such as an oxide, a sulfide, a halide, or an oxysulfide; as an elemental metal; or as a combination with one or more other ingredients of the catalyst. Desirably, the noble metal exists in a reduced state as an elemental metal. Although the noble metal may be present in the final catalyst in any catalytically effective amount, typically the noble metal will comprise 0.01 to 2%, preferably 0.05 to 1%, by weight of the final catalyst, calculated on an elemental basis. [0025] An IUPAC 14 metal may also be incorporated into the catalyst. Of the IUPAC 14 metals, germanium and tin are preferred. The IUPAC 14 metal may be present as an elemental metal; as a chemical compound such as an oxide, a sulfide, a halide, or an oxychloride; or as a physical or chemical combination with the porous carrier material and/or other components of the catalyst. Preferably, a substantial portion of the IUPAC 14 metal exists in a finished catalyst in an oxidation state above that of the elemental metal. Generally, the IUPAC 14 metal is present in an amount of 0.01% to 5%, by weight, preferably 0.1% to 2%, by weight, calculated on an elemental basis. The noble metal and IUPAC 14 metal may be incorporated into the catalyst in any suitable manner, such as disclosed in US 2005/0277796.
[O026] The catalyst may contain other additional metal components, such as rhenium, cobalt, nickel, indium, gallium, zinc, uranium, dysprosium, thallium, or a mixture thereof. A catalytically effective amount of such a metal component may be incorporated into the catalyst by any means known in the art to effect a homogeneous or stratified distribution. [O027] The catalyst may contain a halogen component, such as fluorine, chlorine, bromine, iodine, or a mixture thereof, with chlorine being preferred. Desirably, however, the catalyst contains no added halogen other than that associated with other catalyst components. The elemental analysis of the catalyst components can be determined by Inductively Coupled Plasma (ICP) analysis. Particularly, some components, such as the noble metal, can be measured by UOP Method 873-86 and other components, such as zeolite or binder where each may contain silica, can be measured by UOP Method 961-98. [O028] Generally, the catalyst is dried, calcined, and reduced according to any suitable method, including those disclosed in US 2005/0277796. In some cases, the resulting reduced catalyst may also be subjected to presulftding with, for example, neat H2S at room temperature to incorporate in the catalyst composite from 0.05 to 1.0%, by weight, sulfur, calculated on an elemental basis. [0029] The catalyst can be included in a zone to isomerize alkylaromatic hydrocarbons, for example, those of the general formula C6H(6-n)Rn, where n is an integer from 2 - 5 and R is CH3, C2H5, C3H7, or C4H9, in any combination including all the isomers thereof. Suitable alkylaromatic hydrocarbons may include, for example, an ortho-xylene, a meta-xylene, a para-xylene, an ethylbenzene, an ethyltoluene, a tri-methylbenzene, a di-ethylbenzene, a tri- ethyl-benzene, a methylpropylbenzene, an ethylpropylbenzene, a di-isopropylbenzene, or a mixture thereof. [0030] One desired application of the catalyst is the isomerization of a C8 aromatic mixture containing ethylbenzene and one or more xylenes. Generally the mixture has an ethylbenzene content of 1% to 50%, by weight, an ortho-xylene content of 0% to 35%, by weight, a meta-xylene content of 20% to 95%, by weight, and a para-xylene content of 0% to 30%, by weight. A non-equilibrium mixture of at least one C 8 aromatic isomer is present in a concentration that can differ substantially from the equilibrium concentration at isomerization conditions. Usually, the non-equilibrium mixture is prepared by removal of para-, ortho- and/or meta-xylene from a fresh C 8 aromatic mixture obtained from an aromatic production process. [O031] The alkylaromatic hydrocarbons may be found in an appropriate fraction from various refinery petroleum streams, e.g., as individual components or as certain boiling-range fractions obtained by the selective fractionation and distillation of catalytically cracked or reformed hydrocarbons. Concentration of the isomerizable aromatic hydrocarbons may be optional. A C8 aromatics feed may contain nonaromatic hydrocarbons, i.e., naphthenes and paraffins, in an amount up to 30%, by weight. Preferably the isomerizable hydrocarbons consist essentially of aromatics.
[O032] Generally, a catalyst is utilized until it is spent. At that time the catalyst can be regenerated to remove carbonaceous deposits. Any amount of carbon may be present on the catalyst, but generally the amount of carbon can be up to 5%, by weight, desirably up to 3%, by weight, and optimally up to 2.5%, by weight based on the weight of the catalyst. [OO33] The regeneration process generally entails one or more stages, preferably two stages, of contacting the catalyst with an oxidizing gas. Typically, the oxidizing gas is air. The contacting for both stages can be conducted in an atmosphere including an inert gas, such as nitrogen, and the oxidizing gas. The atmosphere can generally include 1 to 20 mole percent, preferably 2 to 15 mole percent, of oxygen. The oxygen content can be varied during the stage depending on a temperature of an exotherm. The stages can be conducted in the presence of water or steam, such as up to 5.0 mole percent, preferably 2.5 mole percent, steam at 101.325 kPa. Although water is usually undesired component in a regeneration process, typically a commercial unit may have a partial pressure of, e.g., 3 kPa, of water in a pressurized burn. Furthermore, the stages can also be conducted in the presence of halogen, such as chloride. The halogen can be present in amount of 10:1 to 250:1 wateπCl mole ratio, preferably 40:1 to 225:1.
[0034] The first stage oxidation can be conducted at a temperature of 245 to 5000C, desirably 245 to 400° C, and optimally 270 to 390° C. for a selected first time period of 0.5 to 3 days, preferably 0.5 to 1.5 days. The second stage oxidation can be conducted at temperature of 350 to 500° C, preferably 350 to 400° C. for a selected second time period of 0.5 to 3 days, preferably 0.5 to 1.5 days. Typically the temperature and/or time period of the first stage oxidation is different than the respective temperature and/or time period of the second stage oxidation. Preferably, the initial temperature of the first stage oxidation is lower than the second stage oxidation. Generally, the time periods of the first and second oxidation stages are of sufficient length so no significant amount of oxidizing gas is reacted at the end of the respective stage. Afterwards, the oxidized catalyst can be contacted with a reducing agent, such as hydrogen, in an atmosphere including up to 100 mole percent hydrogen. The conditions can include a temperature of 200 to 65O0C, preferably 400 to 4500C Furthermore, the catalyst can be cold sulfided with neat H2S at room temperature to incorporate in the catalyst from 0.05 to 1.0%, by weight, sulfur calculated on an elemental basis to replace sulfur on the platinum.
[O035] Accordingly, such a C 8 aromatic mixture can be contacted with the regenerated catalyst in an alkylaromatic hydrocarbon isomerization zone, such as disclosed in US 2005/0277796, for isomerizing, e.g., ethylbenzene into one or more xylenes.
ILLUSTRATIVE EMBODIMENTS [O036] The following examples are intended to further illustrate the one or more embodiments disclosed above. These illustrations of embodiments of the invention are not meant to limit the claims of this invention to the particular details of these examples. These examples are based on engineering calculations and actual operating experience with similar processes. Example 1 :
[0037] An oil-dropped sphere catalyst contains 0.32%, by weight, platinum; 5%, by weight, MTW zeolite; and the remainder, by weight, alumina. This catalyst is subjected to an isomerization process to accumulate 2.5%, by weight, carbon. [0038] The spent catalyst is sandwiched between an effective amount of a top layer of alumina-supported platinum catalyst spheres and a bottom layer of gamma-alumina spheres. The top layer catalyzes HCl and air to chlorine gas and water that may pass through the spent catalyst. The spent catalyst is regenerated with two burn stages. [0039] The first burn stage is conducted at an initial temperature of 355°C. for 28 hours in an atmosphere containing 2.4%, by mole, steam at 101.325 kPa and a water: chloride mole ratio of 222: 1. The atmosphere can contain 2%, by mole, oxygen for the first 24 hours and 15%, by mole, oxygen for the last 4 hours. The maximum bed temperature is 396°C. The air flow is stopped if the exotherm exceeds a delta of 350C. (a temperature of 390°C.) and restarted once the temperature falls to a delta of 13°C. (a temperature of 3680C). [0040] Specifically, the bed is purged with nitrogen at 1150 cc/minute for 15 minutes at room temperature. Next, the bed is ramped at 2° C./minute to 150° C. and held for 0.5 hours at that temperature. Afterwards, the temperature is ramped at 2° C./minute to 355° C. and held to stabilize the temperature before introducing air. Air at 125 cc/minute and a 0.25 M HCl solution at a delivery rate of 1.4 cc/hour can be introduced with the air introduction being stopped and started depending on the exotherm temperature, as discussed above. These parameters are maintained for 24 hours. Afterwards, the air is increased to 920 cc/minute and nitrogen is decreased to 355 cc/minute and held for 3.5 hours. Next, the HCl injection is stopped and the temperature is maintained at 355° C. for 0.5 hours. That being done, the catalyst is cooled with air and nitrogen to room temperature. [O041] The second burn stage is conducted at an initial temperature of 37O0C. for 28 hours in an atmosphere containing 2.4%, by mole, steam at 101.325 kPa and a water: chloride mole ratio of 222: 1. The atmosphere can contain 2%, by mole, oxygen for the first 24 hours and 15%, by mole, oxygen for the last 4 hours. The air flow is stopped if the exotherm exceeds a delta of 35°C. (a temperature of 4050C.) and restarted once the temperature falls to a delta of 130C. (a temperature of 383°C). [0042] Specifically, the bed is purged, if desired, with nitrogen at 1150 cc/minute for 15 minutes at room temperature. Next, the bed is ramped at 2° C./minute to 150° C. and held for 0.5 hours at that temperature. Afterwards, the temperature is ramped at 2° C./minute to 370° C. and held to stabilize the temperature before introducing air. Air at 125 cc/minute and a 0.25 M HCl solution at a delivery rate of 1.4 cc/hour can be introduced with the air introduction being stopped and started depending on the exotherm temperature, as discussed above. These parameters are maintained for 24 hours. Afterwards, the air is increased to 920 cc/minute and nitrogen is decreased to 355 cc/minute and held for 3.5 hours. Next, the HCl injection is stopped and the temperature is maintained at 355° C. for 0.5 hours. That being done, the catalyst is cooled with air and nitrogen to room temperature.
[O043] After the two bum stages, the catalyst is reduced in an atmosphere of 100%, by mole, hydrogen for two hours at 425° C. The catalyst has 0.5%, by weight, carbon remaining as measured after reduction. Next, the catalyst is cold-sulfided to 0.05%, by weight, sulfur. [O044] At the same weight hourly space velocity (may be referred to as WHSV), reaction severity and temperature in a screening evaluation, the regenerated catalyst is 20% less active for isomerizing than fresh catalyst. This lower isomerization activity is unexpected because xylene isomerization activity generally increases after regeneration. In addition, the ethylbenzene isomerization activity and C8 ring loss are substantially the same as fresh catalyst. The "C8 ring loss" is the loss of C8 rings, in mole or weight percent, that can be converted into a desired C8 aromatic. This example suggests that the milder conditions and/or presence of a higher residual carbon level on the catalyst can prevent the increased activity that typically occurs.
Example 2:
[0045] A trilobe extrudate catalyst contains 0.3%, by weight, platinum; 8%, by weight, MTW zeolite; and the remainder, by weight, alumina. This catalyst is subjected to an isomerization process to accumulate 2.9%, by weight, carbon.
[O046] The spent catalyst is sandwiched between a top layer of an effective amount of alumina-supported platinum catalyst spheres and a bottom layer of gamma-alumina spheres. The spent catalyst is regenerated with two burn stages. [0047] The first burn stage is conducted at an initial temperature of 355°C. for 26 to 28 hours in an atmosphere containing 2.4%, by mole, steam at 101.325 kPa and a water: chloride mole ratio of 40: 1 , The atmosphere can contain 2%, by mole, oxygen for the first 24 hours and 15%, by mole, oxygen for the last 4 hours. The maximum bed temperature is 384°C. The air flow is stopped if the exotherm exceeds a delta of 15°C. (a temperature of 370°C.) and restarted once the temperature falls to a delta of 70C. (a temperature of 3620C). [0048] Specifically, the bed is purged with nitrogen at 1150 cc/minute for 15 minutes at room temperature. Next, the bed is ramped at 2° C./minute to 150° C. and held for 0.5 hours at that temperature. Afterwards, the temperature is ramped at 2° C./minute to 355° C. and held to stabilize the temperature before introducing air. Air at 125 cc/minute and a 1.4 M
HCl solution at a delivery rate of 1.4 cc/hour can be introduced with the air introduction being stopped and started depending on the exotherm temperature, as discussed above. These parameters are maintained for 22 to 24 hours. Afterwards, the air is increased to 920 cc/minute and nitrogen is decreased to 355 cc/minute and held for 3.5 hours. Next, the HCl injection is stopped and the temperature is maintained at 355° C. for 0.5 hours. That being done, the catalyst is cooled with air and nitrogen to room temperature. [O049] The second burn stage is conducted at an initial temperature of 3700C. for 28 hours in an atmosphere containing 2.4%, by mole, steam at 101.325 kPa and a water.chloride mole ratio of 222:1. The atmosphere can contain 2%, by mole, oxygen for the first 24 hours and 15%, by mole, oxygen for the last 4 hours. The maximum bed temperature is 381°C. The air flow is stopped if the exotherm exceeds a delta of 150C. (a temperature of 3850C.) and restarted once the temperature falls to a delta of 7°C. (a temperature of 377°C). [O050] Specifically, the bed is purged, if desired, with nitrogen at 1150 cc/minute for 15 minutes at room temperature. Next, the bed is ramped at 2° C./minute to 150° C. and held for 0.5 hours at that temperature. Afterwards, the temperature is ramped at 2° C./minute to 370° C. and held to stabilize the temperature before introducing air. Air at 125 cc/minute and a 0.25 M HCl solution at a delivery rate of 1.4 cc/hour can be introduced with the air introduction being stopped and started depending on the exotherm temperature, as discussed above. These parameters are maintained for 24 hours. Afterwards, the air is increased to 920 cc/minute and nitrogen is decreased to 355 cc/minute and held for 3.5 hours. Next, the HCl injection is stopped and the temperature is maintained at 355° C. for 0.5 hours. That being done, the catalyst is cooled with air and nitrogen to room temperature. The catalyst has 0.25%, by weight, carbon remaining as measured after oxidation.
[0051] After the two burn stages, the catalyst is reduced in an atmosphere of 100%, by mole, hydrogen for two hours at 425° C. Next, the catalyst is cold-sulfided to 0.05%, by weight, sulfur.
[0052] At the same temperature, reaction severity, and three separate WHSV conditions, all aspects of the regenerated catalyst, including xylene and isomerization activity and C8 ring loss are substantially the same as fresh catalyst. This result suggests that the milder conditions and/or presence of a higher residual carbon level on the catalyst may prevent an increase in isomerization activity that typically occurs.
Example 3:
[O053] A trilobe extrudate catalyst contains 0.3%, by weight, platinum; 5%, by weight, MTW zeolite; and the remainder, by weight, alumina. This catalyst is divided into two portions. The first portion accounting for 25% of the total catalyst weight is subjected to a single isomerization process and regeneration cycle to accumulate 1.1%, by weight, carbon. The second portion accounting for 75% of the total catalyst weight is subjected to a second isomerization process and regeneration cycle, after an initial isomerization process cycle and subsequent regeneration to accumulate 4.1%, by weight, carbon. [O054] The catalyst portions are separated into separate layers in a four-layer regeneration bed. The regeneration bed has a top layer of an effective amount of alumina-supported platinum catalyst spheres, a second layer of the second catalyst portion, a third layer of the first catalyst portion, and a bottom layer of gamma-alumina spheres. Three sheets of quartz wool separate adjacent layers, namely a first sheet is between the top and second layers, a second sheet is between the second and third layers, and a third sheet is between the third and fourth layers. The spent catalyst including the first and second portions is regenerated with two burn stages
[O055] The first burn stage is conducted at an initial temperature of 355°C. for 28 hours in an atmosphere containing 2.4%, by mole, steam at 101.325 kPa and a waterxhloride mole ratio of 40: 1. The atmosphere can contain 2%, by mole, oxygen for the first 24 hours and 15%, by mole, oxygen for the last 4 hours. The maximum bed temperature is 3840C. The air flow is stopped if the exotherm exceeds a delta of 150C. (a temperature of 3700C.) and restarted once the temperature falls to a delta of 7°C. (a temperature of 362°C). [0056] Specifically, the bed is purged with nitrogen at 1150 cc/minute for 15 minutes at room temperature. Next, the bed is ramped at 2° C./minute to 150° C. and held for 0.5 hours at that temperature. Afterwards, the temperature is ramped at 2° C./minute to 355° C. and held to stabilize the temperature before introducing air. Air at 125 cc/minute and a 1.4 M HCl solution at a delivery rate of 1.4 cc/hour can be introduced with the air introduction being stopped and started depending on the exotherm temperature, as discussed above. These parameters are maintained for 24 hours. Afterwards, the air is increased to 920 cc/minute and nitrogen is decreased to 355 cc/minute and held for 3.5 hours. Next, the HCl injection is stopped and the temperature is maintained at 355° C. for 0.5 hours. That being done, the catalyst is cooled with air and m'trogen to room temperature.
[0057] The second burn stage is conducted at an initial temperature of 3700C. for 28 hours in an atmosphere containing 2.4%, by mole, steam at 101.325 kPa and a water: chloride mole ratio of 222: 1. The atmosphere can contain 2%, by mole, oxygen for the first 24 hours and 15%, by mole, oxygen for the last 4 hours. The maximum bed temperature is 377°C. The air flow is stopped if the exotherm exceeds a delta of 150C. (a temperature of 385°C.) and restarted once the temperature falls to a delta of 7°C. (a temperature of 377°C). [O058] Specifically, the bed is purged, if desired, with nitrogen at 1150 cc/minute for 15 minutes at room temperature. Next, the bed is ramped at 2°C./minute to 1500C. and held for 0.5 hours at that temperature. Afterwards, the temperature is ramped at 2°C./minute to 3700C. and held to stabilize the temperature before introducing air. Air at 125 cc/minute and a 0.25 M HCl solution at a delivery rate of 1.4 cc/hour can be introduced with the air introduction being stopped and started depending on the exotherm temperature, as discussed above. These parameters are maintained for 24 hours, except the delivery of water and HCl solution can be stopped for 12 hours. Afterwards, the air is increased to 920 cc/minute and nitrogen is decreased to 355 cc/minute and held for 3.5 hours. Next, the HCl injection is stopped and the temperature is maintained at 3550C. for 0.5 hours. That being done, the catalyst is cooled with air and nitrogen to room temperature. The first portion of catalyst has 0.08%, by weight, carbon and the second portion of catalyst has 0.14%, by weight, carbon remaining as measured after oxidation. [0059] After the two burn stages, the catalyst portions are separately reduced in an atmosphere of 100%, by mole, hydrogen for two hours at 425° C, and cold-sulfided to
0.05%, by weight, sulfur. After sulfiding, the first and second portions are combined for testing activity and C8 ring loss. [0060] At the same temperature, reaction severity, and WHSV condition, all aspects of the regenerated catalyst, including xylene and isomerization activity and C8 ring loss, are substantially the same as fresh catalyst. This result suggests that the milder conditions and/or presence of a higher residual carbon level on the catalyst may prevent the increase in isomerization activity that typically occurs. [0061] Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.
[0062] All the UOP methods, such as UOP-703-98, UOP-873-86, and UOP-961-98, discussed herein can be obtained through ASTM International, 100 Barr Harbor Drive, West
Conshohocken, PA, USA.
[O063] In the foregoing, all temperatures are set forth uncorrected in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated.
[O064] From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.

Claims

CLAIMS:
1. A regeneration process for a C8 alkylaromatic isomerization catalyst, comprising:
A) contacting the C8 alkylaromatic isomerization catalyst with a first gas stream comprising an oxidizing gas at a first stage for a first time period and a first temperature effective to remove at least a portion of a carbonaceous material from the C 8 alkylaromatic isomerization catalyst; and
B) contacting the C 8 alkylaromatic isomerization catalyst with a second gas stream comprising the oxidizing gas at a second stage for a second time period and a second temperature effective to remove another portion of the carbonaceous material from the C 8 alkylaromatic isomerization catalyst;
1) wherein the C8 alkylaromatic isomerization catalyst comprises: a) 1% to 90%, by weight, of a molecular sieve wherein the molecular sieve comprises at least one of an MTW zeolite, an MFI zeolite, a mordenite zeolite and an ATO non-zeolite sieve wherein each zeolite has a silica to alumina mole ratio less than 45:1; b) 10% to99%, by weight, of a binder; and c) 0.1 % to 2%, by weight, of a noble metal, calculated on an elemental basis.
2. The regeneration process according to claim 1, further comprising controlling an exotherm during at least one of the first and second stages by regulating an amount of the oxidizing gas.
3. The regeneration process according to claim 1, further comprising cooling the C8 alkylaromatic isomerization catalyst after the first stage.
4. The regeneration process according to claim 1, wherein the first time period is 0.5 to 3 days and the first temperature is 245 to 500° Celsius.
5. The regeneration process according to claim 1, wherein the second time period is 0.5 to 3 days and the second temperature is 350 to 500° Celsius.
6. The regeneration process according to claim 1, wherein the first time period is 0.5 to 3 days and the first temperature is 270 to 390° Celsius.
7. The regeneration process according to claim 1, wherein the first and second gas streams comprise oxygen and nitrogen.
8. The regeneration process according to claim 7, further comprising: controlling an amount of oxygen in at least one of the first and second gas streams based on the temperature of the stage.
9. The regeneration process according to claim 1, further comprising reducing the C 8 alkylaromatic isomerization catalyst after the second stage.
10. The regeneration process according to claim 9, further comprising sulfiding the reduced C8 alkylaromatic isomerization catalyst.
PCT/US2008/077592 2007-12-03 2008-09-25 Regeneration process for a c8 alkylaromatic isomerization catalyst Ceased WO2009073263A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US11/949,076 2007-12-03
US11/949,076 US20090143218A1 (en) 2007-12-03 2007-12-03 Regeneration process for a c8 alkylaromatic isomerization catalyst

Publications (1)

Publication Number Publication Date
WO2009073263A1 true WO2009073263A1 (en) 2009-06-11

Family

ID=40676344

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2008/077592 Ceased WO2009073263A1 (en) 2007-12-03 2008-09-25 Regeneration process for a c8 alkylaromatic isomerization catalyst

Country Status (2)

Country Link
US (1) US20090143218A1 (en)
WO (1) WO2009073263A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012074613A1 (en) * 2010-11-30 2012-06-07 Exxonmobil Chemical Patents Inc. Method of regenerating zeolite catalyst

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9327278B1 (en) * 2014-12-17 2016-05-03 Uop Llc Process for catalyst regeneration

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4832921A (en) * 1985-12-27 1989-05-23 Uop Inc. Apparatus for regeneration of hydrocarbon conversion catalyst
US6458736B2 (en) * 1994-11-23 2002-10-01 Exxonmobil Chemical Patents Inc. Hydrocarbon conversion process using a zeolite bound zeolite catalyst
US20050277796A1 (en) * 2003-12-30 2005-12-15 Bogdan Paula L Process for C8 alkylaromatic isomerization
US6987078B2 (en) * 2003-10-03 2006-01-17 Fina Technology, Inc. Alkylation and catalyst regenerative process

Family Cites Families (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3230179A (en) * 1963-01-28 1966-01-18 Pullman Inc Regeneration of a platinum catalyst by oxidation and treatment with a hydrogen containing gas
US3856872A (en) * 1973-09-13 1974-12-24 Mobil Oil Corp Xylene isomerization
US4212851A (en) * 1975-12-05 1980-07-15 United States Steel Corporation Regeneration of sulfided dolomite
JPS5732735A (en) * 1980-08-04 1982-02-22 Teijin Yuka Kk Regenerating method for catalyst
US4480144A (en) * 1981-08-06 1984-10-30 Mobil Oil Corporation Regeneration of aromatics processing catalysts
US4508836A (en) * 1982-07-27 1985-04-02 Mobil Oil Corporation Catalytic conversion process for aromatic feedstocks with hydrogen regeneration of coke-selectivated zeolite catalyst
US4700012A (en) * 1986-12-30 1987-10-13 Teijin Petrochemical Industries, Ltd. Process for isomerizing xylene
US4762957A (en) * 1987-06-10 1988-08-09 Uop Inc. Process for isomerization of alkylaromatics
FR2637200B1 (en) * 1988-10-05 1991-01-04 Inst Francais Du Petrole MORDENITE-BASED CATALYST HAVING AT LEAST ONE GROUP VIII METAL AND ITS USE IN ISOMERIZATION OF AN AROMATIC C8 CUT
US5240891A (en) * 1991-12-26 1993-08-31 Patton Robert L Discrete molecular sieve and use
DE19723949A1 (en) * 1997-06-06 1998-12-10 Basf Ag Process for the regeneration of a zeolite catalyst
FR2769623B1 (en) * 1997-10-14 1999-11-12 Inst Francais Du Petrole PROCESS FOR ISOMERIZING AROMATIC COMPOUNDS WITH EIGHT CARBON ATOMS
US6051744A (en) * 1998-12-17 2000-04-18 Chevron Chemical Company Llc Low pressure hydrodealkylation of ethylbenzene and xylene isomerization
US6143941A (en) * 1999-03-03 2000-11-07 Uop Llc Selective xylenes isomerization and ethylbenzene conversion
US6355853B1 (en) * 2000-02-24 2002-03-12 Uop Llc Selective xylenes isomerization and ethylbenzene conversion
US6388159B1 (en) * 2000-11-03 2002-05-14 Uop Llc Xylene isomerization process using UZM-5 and UZM-6 zeolites
US6985282B2 (en) * 2003-08-29 2006-01-10 Bae Systems Information And Electronics Systems Integration Inc. Efficient optical parametric oscillator with photon recycling
US7247762B2 (en) * 2003-09-12 2007-07-24 Exxonmobil Chemical Patents Inc. Process for xylene isomerization and ethylbenzene conversion
US20050143614A1 (en) * 2003-12-30 2005-06-30 Leon-Escamilla E. A. Process and catalyst for C8 alkylaromatic isomerization
US20050143615A1 (en) * 2003-12-30 2005-06-30 Bogdan Paula L. Process and bimetallic catalyst for C8 alkylaromatic isomerization

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4832921A (en) * 1985-12-27 1989-05-23 Uop Inc. Apparatus for regeneration of hydrocarbon conversion catalyst
US6458736B2 (en) * 1994-11-23 2002-10-01 Exxonmobil Chemical Patents Inc. Hydrocarbon conversion process using a zeolite bound zeolite catalyst
US6987078B2 (en) * 2003-10-03 2006-01-17 Fina Technology, Inc. Alkylation and catalyst regenerative process
US20050277796A1 (en) * 2003-12-30 2005-12-15 Bogdan Paula L Process for C8 alkylaromatic isomerization

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012074613A1 (en) * 2010-11-30 2012-06-07 Exxonmobil Chemical Patents Inc. Method of regenerating zeolite catalyst
CN103228357A (en) * 2010-11-30 2013-07-31 埃克森美孚化学专利公司 Method of regenerating zeolite catalyst
CN103228357B (en) * 2010-11-30 2016-03-23 埃克森美孚化学专利公司 Method for regenerating zeolite catalysts

Also Published As

Publication number Publication date
US20090143218A1 (en) 2009-06-04

Similar Documents

Publication Publication Date Title
JP5580744B2 (en) Aromatic isomerization catalysts and methods for their use
US7425660B2 (en) Ethylbenzene conversion and xylene isomerization processes and catalysts therefor
EP3442933B1 (en) Liquid phase xylene isomerization in the absence of hydrogen
TW201202187A (en) Xylene isomerization process and catalyst therefor
JP2010535223A (en) Xylene production method and apparatus using integrated feedstock processing
KR20080016729A (en) 2-step aromatic isomerization method
US8221707B2 (en) Process for isomerizing a non-equilibrium alkylaromatic feed mixture and an aromatic production facility
WO2007032979A2 (en) Process for isomerizing non-equilibrium xylene-containing feed streams
US7456125B2 (en) Ethylbenzene conversion and xylene isomerization processes and catalysts therefor
US7446237B2 (en) Ethylbenzene conversion and xylene isomerization processes and catalysts therefor
US20090143218A1 (en) Regeneration process for a c8 alkylaromatic isomerization catalyst
CN102838444B (en) The aromatics C8 fraction isomerization method improved
WO2009116995A1 (en) Ethylbenzene conversion and xylene isomerization processes and catalysts therefor
US20100092351A1 (en) Molecular Sieve and Catalyst Incorporating the Sieve
KR101622495B1 (en) Aromatics isomerization using a dual-catalyst system
KR100871402B1 (en) Water activation method of alkylaromatic isomerization catalyst

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: 08857824

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: 08857824

Country of ref document: EP

Kind code of ref document: A1