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
  • C10G11/182—Regeneration

Definitions

• the present invention relates to a composition suitable for reducing NO x emissions during catalyst regeneration in a fluid catalytic cracking process.
• FCC fluid catalytic cracking
• catalyst particles inventory
• catalyst regeneration zone In regeneration, coke deposits (from the cracking reaction) on the catalyst particles are removed at elevated temperatures by oxidation. The removal of coke deposits restores the activity of the catalyst particles to the point where they can be reused in the cracking reaction.
• Catalysts comprising transition metals and oxidic supports have been developed to reduce emissions such as NO x for other fields of use, such as automotive exhausts (Tauster SJ, Murrell LU, Catal 197641(1) 192-5) as well as for use in FCC processes.
• US6129834, US6143167, US6280607 and US6379536 provide " compositions suitable for use in FCC processes which are capable of providing NO x control (sold under the commercial name of DENO ⁇ TM). These compositions comprise an acidic oxide support, an alkali metal and/or alkaline earth metal or mixtures thereof, a transition metal oxide having oxygen storage capability and a transition metal selected from Groups lb and/or lib of the Periodic Table.
• US6165933 and US6358881 concern compositions capable of promoting CO combustion while avoiding mass NO x formation comprising an acidic oxide support, an alkali metal and/or alkaline earth metal or mixtures thereof, a transition metal oxide having oxygen storage capability and palladium (commercially available as XNO ⁇ TM). Whilst use of these compositions does result in decreased NO x emissions, there still remains a need for more effective NO x control additives suitable for use in the FCC processes.
• compositions suitable for use in FCC processes that are capable of providing superior NO x control performance compared to the above mentioned DENO ⁇ and XNO ⁇ technology.
• the invention provides compositions for reducing NO x emissions in FCC processes, the compositions comprising: (i) an acidic oxide support; and (ii) a transition metal of Group VIII of the Periodic Table or a salt thereof, and catalysts comprising said compositions.
• the invention encompasses processes using the NO x reduction compositions of the invention either as an integral part of the FCC catalyst particles themselves or as separate admixture particles in the FCC catalyst inventory.
• composition suitable for use in a fluidised catalytic cracking process comprising: (i) an acidic oxide support; and
• the invention also provides a fluid cracking catalyst which comprises: a) a component suitable for cracking the feedstock hydrocarbons; and b) a composition comprising: (i) an acidic oxide support; and (ii) 0.0001 to 10 parts by weight (measured as a metal) of a transition metal of Group VIII of the Periodic Table or a salt thereof per 100 parts by weight of the acidic oxide support.
• the invention also gives a method of reducing NO x emissions during fluid catalytic cracking of a hydrocarbon feedstock into lower molecular weight components, comprising contacting the feedstock with a cracking catalyst at elevated temperature wherein said cracking catalyst comprises:
• composition comprising: (i) an acidic oxide support; and (ii) 0.0001 to 10 parts by weight (measured as a metal) of a transition metal of Group VIII of the Periodic Table or a salt thereof per 100 parts by weight of the acidic oxide support.
• compositions may further contain a metal oxide having oxygen storage capability.
• the acidic oxide support may comprise one or more of the following species: alumina and an aluminosilicate.
• the Group VIII transition metal is preferably rhodium or iridiu , or a salt thereof.
• compositions of the present invention comprising a Group VIII transition metal or salt thereof on an acidic oxide support, without the presence of CO (oxidation) promoters, show superior NO x reduction performance over the additives of the prior art.
• composition of the present invention is preferably in particulate form; preferably the particles have a size of from 10 to 500 ⁇ m, for example 20 to 200 ⁇ m.
• the acidic oxide support of the present invention can be crystalline or amorphous and preferably comprises an alumina, [such as ⁇ -alumina, or CPBase-alumina (of GRACE Davison)], or an aluminosilicate, [for example kaolin or a zeolite such as H-ZSM-5].
• alumina supports are preferred, in particular CPBase-alumina. Details regarding the characteristics of CPBase-alumina are given below:
• the support should have a surface area sufficient to promote the NO x reduction process, for example of at least 50 m 2 /g, for example of from 70 to 200 m 2 /g.
• the transition metal of Group VIII of the periodic table or salt thereof may be any of iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium or platinum or mixtures thereof. Rhodium and iridium are preferred and iridium is particularly preferred.
• the transition metal, or salt thereof is present in an amount of from 0.0001 to 10, for example from 0.0001 to 5, from 0.1 to 0.5, from 0.05 to 0.1 or from 0.01 to •0.1 parts by weight of the transition metal per 100 parts by weight of the acidic oxide support.
• the composition may optionally further comprise a metal oxide having oxygen storage capability.
• the metal oxide may be any non-stoichiometric metal oxide which possess oxygen storage capability.
• the metal oxide comprises ceria.
• the metal oxide is preferably present as a microdispersed phase.
• the metal oxide is preferably present in an amount of from 2 to 50, for example from 10 to 20, parts by weight of the metal per 100 parts of the acidic oxide support.
• composition of the present invention may contain minor amounts of other materials that do not significantly affect its capability to reduce NO x .
• the composition may be combined with fillers (such as clay, silica, alumina or aluminosilicate particles) and/or binders (such as silica sol, alumina sol, aluminosilicate sol).
• the present composition may be used either as an integral part of the FCC catalyst particles themselves or as separate admixture particles in the FCC catalyst inventory. WTien the present composition is used as a separate admixture, the additive particles preferably have a size of from 10 to 500 ⁇ m, for example 20 to 200 ⁇ m and contain the present composition in an amount of from 25 to 100%, for example of at least 50%, preferably of at least 75%, more preferably in an amount of 100%.
• the present composition may be used as an integral part of the FCC catalyst particles in which case any conventional FCC catalyst components may be mixed with the present composition. In such a case, the present composition is preferably present in an amount of greater than 0.02 wt %, preferably from 0.1 to 15 wt %.
• the invention is not limited to any particular process of manufacture, however the present composition is preferably made by the following method: a) impregnate the acidic oxide support particles with a source of a Group VIII transition metal, or salt thereof (for example by wet incipient impregnation methods) to obtain the required metal loading; and b) calcine the impregnated support of step a).
• step a) is preceded with steps al) and a2):
• step al impregnate the acidic oxide with a source of the metal oxide; and a2) calcine the impregnated support of step al).
• the sources of Group VIII transition metals [step a)] are preferably solutions of the salts of the transition metals.
• a suitable source of iridium is an organic solution of Ir ex acac or an aqueous solution of IrCl 3 .
• a suitable source of rhodium is an aqueous solution of RhGl 3 .
• Sources of the metal oxide [step al)] are preferably slurries, sols and/or solutions of the metal oxides themselves or salts of the metal which decompose to form the oxides during step a2).
• a suitable source of ceria is Ce(NO 3 ) 3 .
• the impregnated samples are then preferably dried in an oven before being calcined. Drying is carried out for from 1 to 12 hours, typically 10 hours at a temperature of from 80 to 250°C, for example at from about 110 to about 150 °C .
• Calcination step b) is preferably carried out in air at from 350 to 750 °C, for example at around 600, 650 or 700 °C for between 2 to 10 hours, for example for 3, 6 or 9 hours.
• Calcination step a2) is carried out in air at from 450 to 550 °C, for example at 500 ° C, for between 2 to 4 hours, for example for 3 hours.
• the composition particles produced by the above method may be used directly or may subsequently be mixed with binders and/or fillers by any conventional technique and used as separate admixture particles in the FCC catalyst inventory. Alternatively, the composition particles may be incorporated into the FCC catalyst particles by any known technique to form an integral part of the FCC catalyst particles.
• compositions of the present invention may be used in any conventional FCC process for processing of any typical hydrocarbon feedstock. FCC processes are typically carried out at temperatures of from 450 to 600 °C and catalyst regeneration temperatures of from 600 to 850 °C.
• the present composition is preferably present in an amount of from 0.1 to 15 wt% based on the weight of the FCC catalyst present in the inventory.
• compositions of the present invention may be used alongside other emission reducing additives, such as additives to reduce NO x , CO or SO x emissions, for example DENO ⁇ , XNO ⁇ .
• additives to reduce NO x , CO or SO x emissions for example DENO ⁇ , XNO ⁇ .
• Such additives may be present as separate additives, be present within the particles of the present composition or be present within the FCC catalyst particulate (which optionally comprises the present composition).
• Table 2 Compositions of the present invention (present in the inventory at a concentration of 0.5 wt %) were tested in CPERI FCC pilot plant using an equilibrium FCC catalyst. This plant features a circulating riser operating with a conversion of 72-77 %wt, a catalyst/oil (C/O) ratio of 10-16, a riser temperature of 537-548 °C, a regenerator temperature of from 693-704 °C and a catalyst inventory of 3500-4000g. Emissions were compared to those produced when a standard CO (combustion) promoter is used - in this case CP-3TM (of Grace Davison). The results are shown in Table 3.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Catalysts (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Exhaust Gas Treatment By Means Of Catalyst (AREA)

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• 2003
  • 2003-07-16 GB GB0316659A patent/GB0316659D0/en not_active Ceased
• 2004
  • 2004-07-15 WO PCT/GB2004/003060 patent/WO2005007779A1/en active Application Filing
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