Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G11/00—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
  • C10G11/14—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils with preheated moving solid catalysts
  • C10G11/18—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils with preheated moving solid catalysts according to the "fluidised-bed" technique
• • 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
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
  • B01J23/84—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • B01J23/843—Arsenic, antimony or bismuth
  • B01J23/8435—Antimony
• • 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
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/0201—Impregnation
  • B01J37/0205—Impregnation in several steps
• • 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
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/0201—Impregnation
  • B01J37/0211—Impregnation using a colloidal suspension
• • 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
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/024—Multiple impregnation or coating
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G11/00—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
  • C10G11/02—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils characterised by the catalyst used
  • C10G11/04—Oxides
  • C10G11/05—Crystalline alumino-silicates, e.g. molecular sieves
• • 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
  • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
  • B01J21/16—Clays or other mineral silicates
• • 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
  • B01J37/12—Oxidising
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G2300/00—Aspects relating to hydrocarbon processing covered by groups C10G1/00 - C10G99/00
  • C10G2300/20—Characteristics of the feedstock or the products
  • C10G2300/201—Impurities
  • C10G2300/205—Metal content
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
  • C10G2400/02—Gasoline
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
  • C10G2400/20—C2-C4 olefins
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
  • C10G2400/28—Propane and butane

Definitions

• the present invention provides a metal passivator/trap and methods to mitigate the deleterious effect of metals on catalytic cracking of hydrocarbon feedstocks. This objective is achieved through the use of a mixed metal additive as a passivator and a trap for metai contaminants.
• Catalytic cracking is a petroleum refining process that is applied commercially on a very large scale. About 50% of the refinery gasoline blending pool in the United States is produced by this process, with almost all being produced using the fluid catalytic cracking (FCC) process.
• FCC fluid catalytic cracking
• heavy hydrocarbon fractions are converted into lighter products by reactions taking place at high temperatures in the presence of a catalyst, with the majority of the conversion or cracking occurring in the gas phase.
• the FCC hydrocarbon feedstock (feedstock) is thereby converted into gasoline and other liquid cracking products as well as lighter gaseous cracking products of four or fewer carbon atoms per molecule. These products, liquid and gas, consist of saturated and unsaturated hydrocarbons.
• feedstock is injected into the riser section of a FCC reactor, where the feedstock is cracked into lighter, more valuable products upon contacting hot catalyst circulated to the riser-reactor from a catalyst regenerator.
• carbon is deposited onto the catalyst. This carbon, known as coke, reduces the activity of the catalyst and the catalyst must be regenerated to revive its activity.
• the catalyst and hydrocarbon vapors are carried up the riser to the disengagement section of the FCC reactor, where they are separated. Subsequently, the catalyst flows into a stripping section, where the hydrocarbon vapors entrained with the catalyst are stripped by steam injection. Following removal of occluded hydrocarbons from the spent cracking catalyst, the stripped catalyst flows through a spent catalyst standpipe and into a catalyst regenerator.
• catalyst is regenerated by introducing air into the regenerator and burning off the coke to restore catalyst activity. These coke combustion reactions are highly exothermic and as a result, heat the catalyst. The hot, reactivated catalyst fiows through the regenerated catalyst standpipe back to the riser to complete the catalyst cycle.
• the coke combustion exhaust gas stream rises to the top of the regenerator and leaves the regenerator through the regenerator flue.
• the exhaust gas generally contains nitrogen oxides (NOx), sulfur oxides (SOx), carbon monoxide (CO), oxygen (0 2 ), HCN or ammonia, nitrogen and carbon dioxide (C0 2 ).
• the three characteristic steps of the FCC process that the cracking catalyst undergoes can therefore be distinguished: 1 ) a cracking step in which feedstock is converted into lighter products, 2) a stripping step to remove hydrocarbons adsorbed on the catalyst, and 3) a regeneration step to burn off coke deposited on the catalyst. The regenerated catalyst is then reused in the cracking step.
• zeolitic cracking catalysts revolutionized the fluid catalytic cracking process. New processes were developed to handle these high activities, such as riser cracking, shortened contact times, new regeneration processes, new improved zeolitic catalyst developments, and the like.
• the new catalyst developments revolved around the development of various zeolites such as synthetic types X and Y and naturally occurring faujasites; increased thermal-steam (hydrothermal) stability of zeolites through the inclusion of rare earth ions or ammonium ions via ion-exchange techniques; and the development of more attrition resistant matrices for supporting the zeolites.
• the zeoiitic catalyst developments gave the petroleum industry the capability of greatly increasing throughput of feedstock with increased conversion and selectivity while employing the same units without expansion and without requiring new unit construction.
• Petroleum resid(ue) is the heavy fraction remaining after distillation of petroleum crudes at atmospheric pressure (atmospheric resid) or at reduced pressure (vacuum resid).
• Resids have a high molecular weight and most often contain polycyclic aromatic hydrocarbons (PAH's). These molecules have more than 3-4 aromatic rings and provide the greatest limitation to the conversion of the resids into the desired products. This is because of their high stability and the lack of sufficient hydrogen in the ring structures to be converted to smaller more useful molecules.
• the desired products e.g. transportation fuels, are limited to alkylated single aromatic rings. No matter which type of resid conversion process is applied, a substantia! fraction of resid molecules have fragments, which can be cracked off to become liquids (or gas) in the
• Typical contaminant metals are nickel, vanadium, and iron.
• the literature in this field has reported that vanadium compounds present in feedstock become incorporated in the coke which is deposited on the cracking catalyst and is then oxidized to vanadium pentoxide in the regenerator as the coke is burned off (M. Xu et al. J. Catal. V. 207 (2), 237-246).
• V will be in a surface mobile state in an acidic form. This V species reacts with cationic sodium, facilitating its release from the Y exchange site.
• the sodium metavanadate thus formed hydrolyzes in steam to form NaOH and metavanadic acid, which may again react with Na+ cations. V thus catalyzes the formation of the destructive NaOH.
• Nickel and nickel on the other hand are not mobile.
• the nickel containing hydrocarbons deposits on the catalyst and forms nickel oxide in the regenerator.
• it may be reduced to metallic nickel, which, like metallic iron, catalyzes the dehydrogenation of hydrocarbons to form undesired hydrogen and coke.
• High hydrogen yields are undesirable because it can lead to limitations in the FCC downstream operations (the wet gas compressor is volume limited). High amounts of coke can otherwise lead to regenerator air blower constraints, which may result reduced feed throughput.
• Trapping or passivation may involve incorporating additives into the cracking catalyst or adding separate additive particles along with the cracking catalyst. These additives combine with the metals and therefore either act as "traps” or “sinks” for mobile V species so that the active component of the cracking catalyst is protected, or passivators for immobile Ni and Fe.
• the metal contaminants are then removed along with the catalyst withdrawn from the system during its normal operation and fresh metal trap is added with makeup catalyst so as to affect a continuous withdrawal of the detrimental metal contaminants during operation.
• the quantity of additive may be varied relative to the makeup catalyst in order to achieve the desired degree of metals trapping and/or passivation.
• alumina in the FCC catalyst particle for trapping vanadium and nickel. Examples of this can be found in commonly assigned U.S. Pat. Nos. 6,716,338 and 6,673,235, which add a dispersible boehmite to the cracking catalysts. Upon calcination, the boehmite is converted to a transitional alumina phase, which has been found useful in passivation of nickel and vanadium contaminants in the hydrocarbon feedstock. Meanwhile, high surface area aluminas may also serve to trap vanadium, protecting the zeolite, but not to passivate vanadium , so that the level of contaminant hydrogen and coke remains high.
• Vanadium can also be trapped and effectively passivated by using alkaline earth metal containing traps (Ca, Mg, Ba) and/or Rare earth based traps, see the commonly assigned and co-pending application 12/572,777; U.S. Patent
• antimony and antimony compounds as passivators are also well known in the patent literature including U.S. Pat. Nos. 3,711 ,422; 4,025,458; 4,031,002; 4,111 ,845; 4,148,714; 4,153,536; 4,166,806; 4,190,552; 4,198,317; 4,238,362 and 4,255,287.
• the antimony reacts with nickel to form a NiSb alloy, which is difficult to reduce under riser conditions thus deactivting nickel for catalyzing the formation of hydrogen and coke. This process is commonly referred to as passivation.
• an ammoxidation catalyst to the FCC regenerator is described as reducing the emissions of NOx and NOx precursors during FCC catalyst regeneration.
• a particular useful ammoxidation catalyst is a mixed oxide of iron antimony and an additional metal, such as Mg, Mn, Mo, Ni, Sn, V or Cu.
• the invention is directed towards an improved metal passivator/trap comprising a mixed metal oxide of antimony, at least one redox element and an optional promoter, and use thereof in trapping metal contaminants during the catalytic cracking of hydrocarbon feedstocks.
• Figure I illustrates a reduction of H 2 yield in wt% resulted from a FCC catalyst containing iron/antimony additive and Flex-Tec® metallated with 3000 ppm of Ni at various conversion rates.
• Figure II illustrates a reduction of H2 yield in wt% resulted from a FCC catalyst containing iron/antimony additive and Flex-Tec® metallated with 3000 ppm of V at various conversion rates.
• Figure lil illustrate a reduction of H 2 yield in wt% with an increase in amounts of an iron/antimony additive, used as a metal passivator/trap with a FCC catalyst contaminated with 3000 ppm of Ni and 3000 ppm of V.
• This invention is directed towards an improved metal passivator/trap and its use in conjunction with a FCC catalyst to catalyze petroleum oil feeds containing significant levels of metals contaminants (i.e. Ni and/or V).
• the metals passivator/trap comprises a mixture of metal oxides to immobilize vanadium and nickel, such that the deactivation effect of the FCC catalyst by the metal contaminants in the hydrocarbon oil feeds is reduced and/or the selectivity towards transportation fuels is increased (of all types utilized in FCC operations).
• the invention is particularly useful in the processing of carbo- metallic oil components found in whole crudes, topped crude, residual oil and reduced crude feeds in a modern fluid catalytic cracking unit.
• the process of the present invention comprises the catalytic cracking of hydrocarbonaceous feedstock using a catalyst mixture which comprises a first component of which is a cracking catalyst preferably contained within a matrix material, and a second component of which comprises a mixed metal oxide alloy as described above having an effectiveness for metals passivation and metals trapping.
• the improvement of the present invention resides in the ability of the catalyst system to function well even when the feedstock contains high levels of metals.
• Passivator is defined as a composition that reduces the activity of unwanted metals, i.e. nickel and vanadium to produce contaminant H2 and coke during the FCC process.
• a "trap” is a composition that immobilizes contaminant metals that are otherwise free to migrate within or between microspheres in the FCC catalyst mixture, i.e. V and Na. A passivator may not necessarily immobilize V and a trap certainly may not passivate V.
• the cracking catalyst component employed in the process of the present invention can be any cracking catalyst of any desired type having a significant activity.
• the catalyst used herein is a catalyst containing a crystalline aluminosilicate, preferably ammonium exchanged and at least partially exchanged with rare earth metal cations, and sometimes referred to as "rare earth-exchanged crystalline aluminum silicate," i.e. REY, CREY, or REUSY; or one of the stabilized ammonium or hydrogen zeolites.
• Typical zeolites or molecular sieves having cracking activity are used herein as a catalytic cracking catalyst are well known in the art.
• Synthetically prepared zeolites are initially in the form of alkali metal aluminosilicates.
• the alkali metal ions are typically exchanged with rare earth metal and/or ammonium ions to impart cracking characteristics to the zeolites.
• the zeolites are crystalline, three-dimensional, stable structures containing a large number of uniform openings or cavities interconnected by smaller, relatively uniform holes or channels.
• the effective pore size of synthetic zeolites is suitably between, but not limited to, 6 and 15 A in diameter.
• Zeolites that can be employed herein include both natural and synthetic zeolites. These zeolites include gmelinite, chabazite, dachiardite, clinoptilolite, faujasite, heulandite, analcite, levynite, erionite, sodalite, cancrinite, nepheline, lazurite, scolecite, natrolite, offretite, mesolite, mordenite, brewsterite, ferrierite, and the like. The faujasites are preferred.
• Suitable synthetic zeolites which can be treated in accordance with this invention include zeolites X, Y, including chemically or hydrothermally dealumintated high silica-alumina Y, A, L, ZK-4, beta, ZSM-types or pentasil, boralite and omega.
• zeolites as used herein contemplates not only aluminosilicates but also substances in which the aluminum is replaced by gallium or boron and substances in which the silicon is replaced by germanium.
• the preferred zeolites for this invention are the synthetic faujasites of the types Y and X or mixtures thereof.
• a catalytic catalyst known as Flex-Tec® from BASF Corporation is also useful.
• the amount of catalytic catalyst used for the present invention is of about 30 to about 95 wt% of the catalyst mixture. An amount of about 50% to about %90 is also useful.
• the zeolites have to be in a proper form, in most cases this involves reducing the alkali metal content of the zeolite to as low a level as possible. Further, high alkali metal content reduces the thermal structural stability, and the effective lifetime of the catalyst will be impaired as a consequence thereof.
• Procedures for removing alkali metals and putting the zeolite in the proper form are well known in the art, for example, as described in U.S. Pat. No. 3,537,816.
• the zeolite can be incorporated into a matrix. Suitable matrix materials include the naturally occurring clays, such as kaolin, hailoysite and
• montmorilionite and inorganic oxide gels comprising amorphous catalytic inorganic oxides such as silica, siiica-alumina, silica-zirconia, silica-magnesia, alumina-boria, alumina-titania, and the like, and mixtures thereof.
• the inorganic oxide gel is a silica-containing gel, more preferably the inorganic oxide gel is an amorphous silica-alumina component, such as a conventional silica- alumina cracking catalyst, several types and compositions of which are commercially available.
• silica is present as the major component in the catalytic solids present in such gels, being present in amounts ranging between about 55 and 100 weight percent.
• active commercial FCC catalyst matrix are derived from pseudo-boehmites, boehmites, and granular hydrated or rehydrateable aluminas such as bayerite, gibbsite and flash calcined gibbsite, and bound with peptizable pseudoboehmite and/or colloidal silica, or with aluminum chlorohydrol.
• the matrix component may suitably be present in the catalyst of the present invention in an amount ranging from about 25 to about 92 weight percent, preferably from about 30 to about 80 weight percent of the FCC catalyst.
• U.S. Pat. No. 4,493,902 discloses novel fluid cracking catalysts comprising attrition- resistant, high zeolitic content, catalytically active microspheres containing more than about 40%, preferably 50-70% by weight Y faujasite and methods for making such catalysts by crystallizing more than about 40% sodium Y zeolite in porous microspheres composed of a mixture of two different forms of chemically reactive calcined clay, namely, metakaolin (kaolin calcined to undergo a strong endothermic reaction associated with dehydroxylation) and kaolin clay calcined under conditions more severe than those used to convert kaolin to metakaolin, i.e., kaolin clay calcined to undergo the characteristic kaolin exothermic reaction, sometimes referred to as the spinel form of calcined kaolin.
• metakaolin kaolin calcined to undergo a strong endothermic reaction associated with dehydroxylation
• the microspheres containing the two forms of calcined kaolin clay are immersed in an alkaline sodium silicate solution, which is heated, preferably until the maximum obtainable amount of Y faujasite is crystallized in the microspheres.
• the porous microspheres in which the zeolite is crystallized are preferably prepared by forming an aqueous slurry of powdered raw (hydrated) kaolin clay (Al 2 0 3 : 2Si0 2 : 2H 2 0) and powdered calcined kaolin clay that has undergone the exotherm together with a minor amount of sodium silicate which acts as fluidizing agent for the slurry that is charged to a spray dryer to form microspheres and then functions to provide physical integrity to the components of the spray dried microspheres.
• powdered raw (hydrated) kaolin clay Al 2 0 3 : 2Si0 2 : 2H 2 0
• sodium silicate acts as fluidizing agent for the slurry that is charged to a spray dryer to form microspheres and then functions to provide physical integrity to the components of the spray dried microspheres.
• the spray dried microspheres containing a mixture of hydrated kaolin clay and kaolin calcined to undergo the exotherm are then calcined under controlled conditions, !ess severe than those required to cause kaolin to undergo the exotherm, in order to dehydrate the hydrated kaolin clay portion of the microspheres and to effect its conversion into metakaolin, this resulting in microspheres containing the desired mixture of metakaolin, kaolin calcined to undergo the exotherm and sodium stiicate binder.
• about equal weights of hydrated clay and spinel are present in the spray dryer feed and the resulting calcined microspheres contain somewhat more clay that has undergone the exotherm than metakaolin.
• the '902 patent teaches that the calcined microspheres comprise about 30-60% by weight metakaolin and about 40-70% by weight kaolin characterized through its characteristic exotherm.
• a less preferred method described in the patent involves spray drying a slurry containing a mixture of kaolin clay previously calcined to metakaolin condition and kaolin calcined to undergo the exotherm but without including any hydrated kaolin in the slurry, thus providing microspheres containing both metakaolin and kaolin calcined to undergo the exotherm directly, without calcining to convert hydrated kaolin to metakaolin.
• microspheres composed of kaolin calcined to undergo the exotherm and metakaolin are reacted with a caustic enriched sodium silicate solution in the presence of a crystallization initiator (seeds) to convert silica and alumina in the microspheres into synthetic sodium faujasite (zeolite Y).
• seeds crystallization initiator
• the microspheres are separated from the sodium silicate mother liquor, ion-exchanged with rare earth, ammonium ions or both to form rare earth or various known stabilized forms of catalysts.
• the technology of the '902 patent provides means for achieving a desirable and unique combination of high zeolite content associated with high activity, good selectivity and thermal stability, as well as attrition-resistance.
• the metal passivator/trap of the present invention reduces vanadium attack and nickel dehydrogenation of the cracking catalyst during FCC cracking of gas oil and resids.
• R is at least one redox element selected from Fe 2+ 3+ , Ce 3+ 4+ , Cr 2+/3+ , U 5+fl5+ , Sn, or Mn r whose role is to make lattice oxygen from O2 and then replenish the Sb 3+ 5+ active sites with this lattice oxygen, each of which can be further improved by the addition of at least one optional promoter, M, selected from oxides of Na, Zn, W, Te, Ca, Ba,
• the current invention is directed towards using iron-antimony
• the FeSb is prepared with a low surface area to limit H 2 formation.
• the Sb is mobile such that the Sb can find and passivate the Ni on the catalyst. Since Sb and V are similar in chemistry (V is also mobile), FeO x can react with V to form FeVO x .
• FeVO* is stable as nonsulfating vanadate in the SOx containing regenerator gas. Without wishing to be bound by any theory of operation, we believe the FeSb structure faciliates the V to get inside or exchange into the iron oxide structure.
• the ratio of R:Sb: is also significant to the catalytic results.
• the atomic ratio of R:Sb:M may be in the range of 0.1-10 to 0.1-10 to 0-10, preferably 0.5-3 to 0.5-3 to 0-5.
• the metal passivator/trap may be blended with separate zeolite catalyst particles before being introduced to an FCC unit.
• the metal passivator/trap may be blended with separate zeolite catalyst particles before being introduced to an FCC unit.
• passivator/trap particles can be charged separately to the circulating catalyst inventory in the cracking unit.
• the metal passivation particles are present in amounts within the range of 1 to 50% by weight, preferably 2 to 30% by weight, and most preferably 5 to 25% by weight of the catalyst mixture.
• improvements in vanadium and nickel passivation may not be sufficient.
• cracking activity and/or selectivity may be impaired, and the operation becomes costly.
• Optimum proportions vary with the level of metal contaminants within oil feeds.
• the concentration of the passivator/trap in the catalyst mixture can be adjusted so as to maintain a desired catalyst activity and conversion rate, preferably a conversion rate of at least 55 percent.
• the passivator/trap of this invention is particularly useful for cracking oil feed containing a level of metal contaminants (i.e. Ni and/or V), having concentrations in the range of about 0.1 ppm of nickel and/or 0.1 ppm of vanadium, to about 200ppm of metal contaminants comprising Nickel, Vanadium, and/or mixture thereof.
• the amount of metal contaminants accumulated on the FCC catalyst can be as minimally as 300ppm to as high as 40,000ppm of metal contaminants comprising Nickel, Vanadium, and/or mixture thereof.
• Inert carrier support material may be used to carry the metal
• the carrier support material is selected from, but not limited to: (i) in situ FCC containing zeolites, (ii) calcined kaolins (iii) alumina or (tv) silica. If silica is used, zirconium can be added to provide thermal stability. Alumina such as Puralox® produced by Sasol is useful. Calcined kaolins in the forms of microspheres are preferred.
• the method of making carriers used for the current invention can be found in the commonly assigned U.S. Patent Number
• the amount of carrier used Is from about 1% to 99 wt%, preferably 5% to 95 wt% of the catalyst mixture.
• the carrier preferably has a surface area of about 5 to 200 m 2 /g.
• the RSbM metal passivator/trap is generally prepared by 1) impregnating a carrier with an antimony solution; 2) impregnating the processed carrier from 1 ) with a solution of the redox element, such that only a portion of the pore volume of the carrier microsphere is filled, and 3) filling the remaining portion of the pore volume with a concentrated ammonium hydroxide solution. Accordingly, antimony chloride or antimony trioxide can be used to prepare the antimony solution.
• the amount of the ammonium used is generally equal to the equivalents of the nitrates plus chlorides. This provides a neutral pH and the precipitation of the dissolved metals inside the microspheres at incipient wetness volume.
• the entrained ammonium nitrate salts can be explosive if dried. Therefore, the impregnated microspheres should be allowed to react for about 30 minutes, then slurried with deionized water, filtered and washed to remove the salts, leaving the RSbM hydrogels in the microspheres. The hydroxide mixture can then be calcined.
• the promoter can be combined with the redox element in the second impregnation, or the ammonium solution in the third impregnation, such that each of the solutions remain fully dissolved and that the overall equivalents are being adjusted to provide neutrality after both the acidic and basic solutions are impregnated,
• the redox element can be added directly to the antimony prior to impregnation onto the inert carrier.
• the incorporation of metal cations in the antimony structure is carried out in a second synthesis step by addition of one or more metal salts (i.e. nitrates, chlorides or acetates) of the redox element: Fe(OAc) 2 + 2 Sb +5 (OH) 3 0 + 2 H 2 0 — > Fe +2 [Sb +5 (OH) 4 0] 2 + 2 HOAc
• the passivator/trap can also be prepared by introducing the metal salts in the production process (spray drying of kaolin clay, followed by calcination) or by co precipitation of Fe and Sb salts without carrier support, see Allen et al., Appl. Catal. A. Gen., 217 (2001), 31.
• the reaction temperature in accordance with the above-described process is at least about 900°F (482°C).
• the upper limit can be about 00°F (593.3°C) or more.
• the preferred temperature range is about 950°F to about 1050°F
• reaction totai pressure can vary widely and can be, for example, about 5 to about 50 psig (0.34 to 3.4 atmospheres), or preferably, about 20 to about 30 psig (1.36 to 2.04 atmospheres).
• the maximum riser residence time is about 5 seconds, and for most charge stocks the residence time will be about 1.0 to about 2.5 seconds or less.
• the length to diameter ratio of the reactor can vary widely, but the reactor should be elongated to provide a high linear velocity, such as about 25 to about 75 feet per second; and to this end a length to diameter ratio above about 20 to about 25 is suitable.
• the reactor can have a uniform diameter or can be provided with a continuous taper or a stepwise increase in diameter along the reaction path to maintain a nearly constant velocity along the flow path.
• the weight ratio of catalyst to hydrocarbon in the feed is varied to affect variations in reactor temperature. Furthermore, the higher the temperature of the regenerated catalyst, the less catalyst is required to achieve a given reaction temperature. Therefore, a high regenerated catalyst temperature will permit the very low reactor density level set forth below and thereby help to avoid back mixing in the reactor.
• catalyst regeneration can occur at an elevated temperature of about 1250°F (676.6°C) or more. Carbon-on-catalyst of the regenerated catalyst is reduced from about 0.6 to about 1.5, to a level of about 0.3 percent by weight.
• the quantity of catalyst is more than ample to achieve the desired catalytic effect and therefore if the temperature of the catalyst is high, the ratio can be safely decreased without impairing conversion.
• zeolitic catalysts are particularly sensitive to the carbon level on the catalyst, regeneration advantageously occurs at elevated temperatures in order to lower the carbon level on the catalyst to the stated range or lower.
• a prime function of the catalyst is to contribute heat to the reactor, for any given desired reactor temperature the higher the temperature of the catalyst charge, the less catalyst is required. The lower the catalyst charge rate, the lower the density of the material in the reactor. As stated, iow reactor densities help to avoid back mixing.
• the catalyst mixture described above can be used in the catalytic cracking of any hydrocarbon charge stock containing metals, but is particularly useful for the treatment of high metals content charge stocks.
• Typical feedstocks are heavy gas oils or the heavier fractions of crude oil in which the metal contaminants are concentrated.
• Particularly preferred charge stocks for treatment using the catalyst mixture of the present invention include deasphalted oils boiling above about 900°F (482°C) at atmospheric pressure; heavy gas oils boiling from about 600°F to about 1100°F (343°C to 593°C) at atmospheric pressure; atmospheric or vacuum tower bottoms boiling above about 650°F.
• the metal passivator/trap may be added to the FCC unit via an additive loader in the same manner as CO promoters and other additives.
• the metal passivator/trap may be pre-blended with the fresh FCC catalyst being supplied to the FCC unit.
• Example 1 Preparing a passivator/trap comprising a mixture of Fe/Sb :
• the impregnated support was left at room temperature to allow the components to react for about 30 minutes, followed by slurried with deionized water, filtered and washed to remove unincorporated particles or salts. Placed the impregnated support (now containing both Fe and Sb) in a Pyrex bowl and dry overnight in a vented 100°C oven. Cooled the support to room temperature, then calcined the support at 400°C for 3hrs in a vented oven.
• Metal passivators/traps comprising promoters were made:
• Flex-Tec in samples J and K was metallated to 3000 ppm of nickel, by adding an appropriated amount of nickel and cyclohexane, mixed and poured onto a cordierite tray to air dry, then burned at 315°C and calcined at 593°C.
• the passivators/traps were then incorporated within pre-metallated FCC catalysts.
• the combinations were the steamed at 1450°F for 4 hours at 90% steam / 10% air prior to testing.
• the hydrogen yield was measured on an ACE fluid-bed hydrocarbon cracking unit using a hydrocarbon oil feed. It can be shown in Figure 1 that at various conversion rates of the catalyst, the hydrogen yield in wt% for sample K was 15% lower than sample J, the control sample.
• Flex-Tec in samples L and M was metallated to contain 3000 ppm of vanadium, by adding an appropriated amount of vanadium and cyclohexane, mixed and poured onto a cordierite tray to air dry, then burned at 315°C and calcined at 593°C.
• the passivators/traps were then incorporated within pre-metallated FCC catalysts.
• the combinations were the steamed at 1450°F for 4 hours at 90% steam / 10% air prior to testing.
• the hydrogen yield was measured on an ACE fluid-bed hydrocarbon cracking unit using a hydrocarbon oil feed. It can be shown in Figure 2 that at various conversion rates of the catalyst, the hydrogen yield in wt% for sample M was 20% lower than sample J, the control sample.
• Flex-Tec in samples N, 0, P, Q and R was metallated to 3000 ppm of nickel and 3000 ppm of vanadium, by adding an appropriated amount of vanadium, nickel, and cyclohexane, mixed and poured onto a cordierite tray to air dry, then burned at 315°C and calcined at 593°C.
• the rate of hydrocarbons being stripped and the amounts of hydrocarbon yields were measured on an ACE fluid-bed hydrocarbon cracking unit using a hydrocarbon oil feed.
• Table 6 shows the hydrocarbon yields for samples P and T at 75% of conversion rate:

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