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
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • B01J23/20—Vanadium, niobium or tantalum
  • B01J23/22—Vanadium
• • 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
  • B01J23/005—Spinels
• • 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

Definitions

• VANADIUM RARE EARTH METAL-CONTAINING SPINEL COMPOSITION AND PROCESS OF USING SAME
• This invention relates to improved vanadium, rare earth metal-containing spinel compositions, particularly for use in a manner to effect a reduction in the emission of sulfur oxides and/or nitrogen oxides to the atmosphere.
• the invention involves compositions and processes for the catalytic cracking of sulfur-containing hydrocarbon feedstocks to effect a reduction in the amount of sulfur oxides and/or nitrogen oxides emitted from the regeneration zone of a hydrocarbon catalytic cracking unit.
• catalytic cracking of hydrocarbons takes place in a reaction zone at hydrocarbon cracking conditions to produce at least one hydrocarbon product and to cause carbonaceous material (coke) to be deposited on the catalyst. Additionally, some sulfur, originally present in the feed hydrocarbons, may also be deposited, e.g., as a component of the coke, on the catalyst.
• Sulfur-containing coke deposits tend to deactivate cracking catalyst.
• Cracking catalyst is advantageously continuously regenerated, by combustion with oxygen-containing gas in a regeneration zone, to low coke levels, typically below about 0.4% by weight, to perform satisfactorily when it is recycled to the reactor.
• the regeneration zone at least a portion of sulfur, along with carbon and hydrogen, which is deposited on the catalyst, is oxidized and leaves in the form of sulfur oxides (sulfur dioxide and sulfur trioxide, hereinafter referred to a "SOx") along with substantial amounts of carbon monoxide, carbon dioxide and water.
• SOx sulfur oxides
• At least a portion of the nitrogen which may be present in the coke deposits and/or in the oxygen-containing gas, is oxidized at the conditions in the regeneration zone to nitrogen oxides which also leave with the flue gas from the regeneration zone.
• a metallic component either incorporated into catalyst particles or present on any of a variety of "inert" supports, is exposed alternately to the oxidizing atmosphere of the regeneration zone of an FCCU and the reducing atmosphere of the cracking zone to reduce sulfur oxide emissions from regenerator gases in accordance with the teachings of U.S. Patents Nos. 4,153,534 and 4,153,535 to Vasalos and Vasalos, et al., respectively.
• a metallic oxidation promoter consisting of components of ruthenium, rhodium, palladium, platinum, osmium, iridium, platinum, vanadium, uranium, zirconium, rhenium, silver and mixtures thereof is also present when carbon monoxide emissions are to be reduced.
• the more preferred metallic promoter consists of components of ruthenium, rhodium, palladium, osmium, iridium, platinum and rhenium.
• These patents disclose nineteen different metallic components, including materials as diverse as alkaline earths, sodium, heavy metals and rare earth, as being suitable reactants for reducing emissions of oxides of sulfur.
• the metallic reactants that are especially preferred are sodium, magnesium, manganese and copper.
• the carriers for the metallic reactants preferably have surface areas of at least 50 square meters per gram. Examples of allegedly "inert" supports are silica, alumina and silica-alumina.
• the Vasalos and Vasalos, et al. patents further disclose that when certain metallic reactants (exemplified by oxides of iron, manganese or cerium) are employed to capture oxides of sulfur, such metallic components can be in the form of a finely divided fluidizable powder.
• sorbents have been proposed for desulfurization of non-FCCU flue gases in zones outside the unit in which SOx is generated.
• the sorbents are regenerated in environments appreciably richer in hydrogen than the cracking zone of an FCC unit.
• Fifteen adsorbents are disclosed for flue gas desulfurization in a publication of Lowell, et al., "SELECTION OF METAL OXIDES FOR REMOVING SOx FROM FLUE GAS," Ind. Eng. Chemical Process Design Development, Vol. 10, Nov. 3, 1971.
• cerium on an alumina support is used to absorb SO2 from non-FCCU flue gas streams or automobile exhaust at temperatures of 572 to 1472 degrees F., preferably 932 to 1100 degrees F.
• Many commercial zeolitic FCC catalyst contain up to 4% rare earth oxide, the rare earth being used to stabilize the zeolite and provide increased activity. See, for example, U.S. Patent No. 3,930,987 to Grand.
• the rare earths are most often used as mixtures of La203, CeO2, Pr6011, Nd203 and others.
• Some catalyst is produced by using a lanthanum-rich mixture obtained by removing substantial cerium from the mixture of rare earth. It has been found that the mere presence of rare earth in a zeolitic cracking catalyst will not necessarily reduce SOx emissions to an appreciable extent.
• certain zeolitic catalyst compositions capable of being regenerated at a rate appreciably faster than prior art rare earth exchanged zeolitic catalyst compositions are produced by treating a previously rare earth exchanged zeolitic catalyst composition with a dilute solution containing cerium cations (or a mixture of rare earths rich in cerium).
• the final catalysts contain 0.5 to 4% cerium cations which are introduced to previously rare earth exchanged zeolitic catalyst particles prior to final filtering, rinsing and calcining. Cerium is described as an "oxidation promoter".
• U.S. Patents 4,469,589 and 4,472,267 relate to improved materials for reducing SOx emissions comprising spinels, preferably alkaline earth metal, aluminum-containing spinels, which materials may contain one or more other metal components capable of promoting the oxidation of sulfur dioxide to sulfur trioxide at combustion conditions.
• Such metallic components include components of Group IB metals, Group IIB metals, Group IVB metals.
• these patents disclose that magnesium, aluminum-containing spinel is impregnated with such other metal components (e.g., cerium and platinum) using conventional techniques.
• the present invention involves a composition, hereinafter referred to as "VRS", comprising at least one metal-containing spinel, preferably a major component of such spinel, which includes a first metal and a second metal having a valence higher than the valence of the first metal, a minor amount of at least one rare earth metal component effective to promote the oxidation of sulfur dioxide to sulfur trioxide at sulfur dioxide oxidation conditions, and a minor amount of at least one vanadium component effective to promote the reduction of first metal sulfate at first metal sulfate reduction conditions.
• VRS composition, hereinafter referred to as "VRS”
• at least one metal-containing spinel preferably a major component of such spinel, which includes a first metal and a second metal having a valence higher than the valence of the first metal
• a minor amount of at least one rare earth metal component effective to promote the oxidation of sulfur dioxide to sulfur trioxide at sulfur dioxide oxidation conditions
• at least one vanadium component effective to promote
• the invention involves a catalyst system comprising, in intimate admixture, a major amount of solid particles capable of promoting hydrocarbon conversion at hydrocarbon conversion conditions, and a minor amount of discrete entities having a chemical make-up which is different from the solid particles and which comprise the VRS described above.
• the present VRS has been found to provide for both outstanding effectiveness in removing sulfur oxides, e.g., from the catalyst regeneration zones of hydrocarbon conversion units, and improved effectiveness in releasing associated sulfur oxide, e.g., in the reaction zones of hydrocarbon conversion units.
• a particularly surprising feature of the present invention involves the use of the VRS in hydrocarbon catalytic cracking units.
• Vanadium is a known catalyst poison in hydrocarbon catalytic cracking units.
• the VRS which contain a vanadium component, provide for outstanding reduction in sulfur oxide and/or nitrogen oxide emissions with no substantial cracking catalyst poisoning.
• the invention relates to a process for reducing at least one, preferably both, of (1) the sulfur oxide content of a sulfur oxide-containing gas and (2) the nitrogen oxide content of a nitrogen oxide-containing gas which comprises contacting the gas with a composition at conditions to reduce at least one, preferably both, of (1) the sulfur oxide content of the gas and (2) the nitrogen oxide content of the gas.
• the composition to be used is the VRS first described above.
• the present invention relates to an improved hydrocarbon conversion, preferably cracking, process for converting a sulfur-containing hydrocarbon feedstock.
• the process comprises (1) contacting the feedstock with solid particles capable of promoting the conversion of the feedstock at hydrocarbon conversion conditions in at least one reaction zone to produce at least one hydrocarbon product and to cause deactivating sulfur-containing carbonaceous material to be formed on the solid particles; (2) contacting the deposit-containing particles with an oxygen-containing vaporous medium at conditions to combust at least a portion of the carbonaceous deposit material in at least one regeneration zone to thereby regenerate at least a portion of the hydrocarbon conversion catalytic activity of the solid particles and to form a regeneration zone flu gas containing sulfur oxide (e.g., sulfur trioxide) and/or nitrogen oxide; and (3) repeating steps (1) and (2) periodically.
• sulfur oxide e.g., sulfur trioxide
• the present improvement comprises using, in intimate admixture with the solid particles, a minor amount of discrete entities having a chemical make-up which is different from the solid particles and which comprise the VRS first described above.
• discrete entities are present in an amount effective to reduce the amount of sulfur oxides and/or nitrogen oxides in the flue gas.
• the discrete entities also include a minor, catalytically effective amount of at least one crystalline material effective to promote hydrocarbon conversion, e.g., cracking, at hydrocarbon conversion conditions.
• the preferred relative amounts of the solid particles and discrete entities are about 80 to about 99 parts and about 1 to about 20 parts by weight, respectively.
• This catalyst system is especially effective for the catalytic cracking of a hydrocarbon feedstock to lighter, lower boiling products.
• the present catalyst system also has improved carbon monoxide oxidation catalytic activity stability.
• the VRS has a surface area (by the conventional B.E.T. method) in the range of about 25m 2 /gm. to about 600m 2 /gm., more preferably about 40m 2 /gm. to about
• the improvement of this invention can be used to advantage with the catalyst (solid particles and discrete entities) being disposed in any conventional reactor-regenerator system, in ebullating catalyst bed systems, in systems which involve continuously conveying or circulating catalyst between reaction zone and regeneration zone and the like. Circulating catalyst systems are preferred. Typical of the circulating catalyst bed systems are the conventional moving bed and fluidized bed reactor-regenerator systems. Both of these circulating bed systems are conventionally used in hydrocarbon conversion, e.g., hydrocarbon cracking, operations with the fluidized catalyst bed reactor-regenerator systems being preferred. Although the presently useful solid particles and discrete entities may be used as a physical admixture of separate particles, in one embodiment, the discrete entities are combined as part of the solid particles.
• the discrete entities e.g., comprising calcined microspheres of the VRS
• the solid particles e.g., during the manufacture of the solid particles
• the discrete entities are preferably present as a separate and distinct phase in the combined particles.
• One preferred method for providing the combined particles is to calcine the discrete entities prior to incorporating the discrete entities into the combined particles.
• the form, i.e., particle size, of the present particles is not critical to the present invention and may vary depending, for example, on the type of reaction-regeneration system employed.
• Such particles may be formed into any desired shape such as pills, cakes, extrudates, powders, granules, spheres and the like, using conventional methods.
• the particles may preferably be formed into particles having a minimum dimension of at least about 0.01 inch and a maximum dimension of up to about one-half inch or one inch or more.
• Spherical particles having a diameter of about 0.03 inch to about 0.25 inch, preferably about 0.03 inch to about 0.15 inch, are often useful, especially in fixed bed or moving bed operations. With regard to fluidized bed systems, it is preferred that the major amount by weight of the particles have a diameter in the range of about 10 microns to about 250 microns, more preferably about 20 microns to about 150 microns.
• the solid particles are capable of promoting the desired hydrocarbon conversion.
• hydrocarbon conversion is meant a chemical reaction or conversion in which one or more of the feed materials or reactants and/or one or more of the products or conversion products is substantially hydrocarbon in nature, e.g., comprises a major amount of weight of carbon and hydrogen.
• the solid particles are further characterized as having a composition (i.e., chemical make-up) which is different from the discrete entities.
• the solid particles (or the solid particles portion of the combined particles described above) are substantially free of VRS.
• composition of the solid particles useful in the present invention is not critical, provided that such particles are capable of promoting the desired hydrocarbon conversion.
• Solid particles having widely varying compositions are conventionally used as catalyst in such hydrocarbon conversion processes, the particular composition chosen being dependent, for example, on the type of hydrocarbon chemical conversion desired.
• the solid particles suitable for use in the present invention include at least one of the natural or synthetic materials which are capable of promoting the desired hydrocarbon chemical conversion.
• such suitable materials include acid-treated natural clays, such as montmorillonite, kaolin and bentonite clays; natural or synthetic emorphous materials, such as alumina, silica, silica-alumina, silica-magnesia and silicazirconia composites; and crystalline materials often referred to as zeolites or molecular sieves, such as aluminosilicates, SAPO, TAPO, MeAPO, LZ-210, LZ-10, USY and the like. Certain of these crystalline materials are discussed in U.S. Patents 4,310,440; 4,440,871; 4,500,651; and 4,503,023, the specification of each of which patents is
• the solid particles preferably include such crystalline materials to increase catalytic activity.
• Methods for preparing such solid particles and the combined solid particles-discrete entities particles are conventional and well known in the art.
• crystalline aluminosilicate compositions can be made from alkali metal silicates and alkali metal aluminates so that they initially contain significant concentrations of alkali metals. Sodium tends to reduce the catalyst activity of the composition for hydrocarbon conversion reactions such as hydrocarbon cracking and disproportionation.
• the sodium in the crystalline aluminosilicate is removed or replaced, e.g., with other metal cations such as calcium or aluminum ions or ions of the rare earths, which are associated with the crystalline aluminosilicates.
• This can be accomplished by contacting the crystalline aluminosilicate with a source of hydrogen ions such as acids, or hydrogen precursors such as ammonium compounds.
• compositions of the solid particles which are particularly useful in the present invention are those in which the crystalline materials is incorporated in an amount effective to promote the desired hydrocarbon conversion, e.g., a catalytically effective amount, into a porous matrix which comprises, for example, amorphous material which may or may not be itself capable of promoting such hydrocarbon conversion. Included among such matrix materials are clays and amorphous compositions of alumina, silica, silica-alumina, magnesia, zirconia, mixtures of these and the like.
• the crystalline material is preferably incorporated into the matrix material in amounts within the range of about 1% to about 75%, more preferably about 2% to about 50%, by weight of the total solid particles.
• the preparation of crystalline-amorphous matrix catalytic materials is described in the above-mentioned patents.
• Catalytically active crystalline materials which are formed during and/or as part of the methods of manufacturing the solid particles, discrete entities and/or as part of the methods of manufacturing the solid particles, discrete entities and/or combined particles are within the scope of the present invention.
• the solid particles are preferably substantially free of added rare earth metal, e.g., cerium, component disposed on the amorphous matrix material of the catalyst, although such rare earth metal components may be associated with the crystalline materials of the solid particles.
• the solid particles useful in the catalytic hydrocarbon cracking embodiment of the present invention may be any conventional catalyst capable of promoting hydrocarbon cracking at the conditions present in the reaction zone, i.e., hydrocarbon cracking conditions. Similarly, the catalytic activity of such solid particles is restored at the conditions present in the regeneration zone.
• Typical among these conventional catalysts are those which comprise alumina, silica and/or silica-alumina and at least one crystalline aluminosilicate having pore diameters of about 8 angstroms to about 15 angstroms and mixtures thereof.
• the crystalline aluminosilicate may include minor amounts of conventional metal promoters such as the rare earth metals, in particular, cerium.
• the present VRS comprise an effective amount, preferably a major amount, of at least one spinel containing a first metal and a second metal, preferably alkaline earth metal-containing spinel, a minor amount of at least one rare earth metal component effective to promote the oxidation of sulfur dioxide to sulfur trioxide at sulfur dioxide oxidation conditions, and a minor amount of at least one vanadium component effective to promote the reduction of first metal, preferably alkaline earth metal sulfate at first metal sulfate reduction conditions.
• the present VRS include amounts of rare metal component and vanadium component which, are effective to promote the reduction of nitrogen oxides at nitrogen oxide reduction conditions.
• the spinel structure is based on a cubic close-packed array of oxide ions.
• the crystallographic unit cell of the spinel structure contains 32 oxygen atoms; one-eighth of the tetrahedral holes (of which there are two per anion) are occupied by divalent metal ion, and one-half of the octahedral holes (of which there are two per anion) are occupied by trivalent metal ions.
• This typical spinel structure or a modification there of is adaptable to many other mixed metal oxides of the type M II M 2 III O 4
• All M IV M 2 II O 4 are inverse, e.g., Zn(ZnTi)O 4 , and many of the
• MII M 2 III O 4 ones are also, e.g., Fe III (Co II Fe III )O 4 ,
• Fe III (Fe II Fe III )O 4 and Fe(NiFe)O 4 .
• CoCo 2 S 4 CuCo 2 S 4 , GeNi 2 O 4 , NiNi 2 S 4 , ZnGa 2 O 4 ,
• the presently useful metal-containing spinels include a first metal and a second metal having a valence (oxidation state) higher than the valence of the first metal.
• the first and second metals may be the same metal or different metals. In other words, the same metal may exist in a given spinel in two or more different oxidation states.
• the atomic ratio of the first metal to the second metal in any given spinel need not be consistent with the classical stoichiometric formula for such spinel.
• the atomic ratio of the first metal to the second metal in the metal-containing spinel useful in the present invention is at least about 0.17 and preferably at least about 0.25. If the first metal is a mono-valent metal, the atomic ratio of the first metal to the second metal is preferably at least about 0.34, more preferably at least about 0.5.
• the preferred metal-containing spinels for use in the present invention are alkaline earth metal spinels, in particular magnesium (first metal) and aluminum (second metal)-containing spinel.
• Other alkaline earth metal ions such as calcium, strontium, barium and mixtures thereof, may replace all or a part of the magnesium ions.
• metal ions such as iron, chromium, vanadium, manganese, gallium, boron, cobalt, Group IB metals, Group IV metals, Group VA metals, the platinum group metals, the rare earth metals, Te, Nb, Ta, Sc, Zn, Y, Mo, W, Tl, Re, U, Th and mixtures thereof, may replace all or a part of the aluminum ions, preferably only a part of the aluminum ions.
• the spinel includes a divalent metal (e.g., magnesium) and a trivalent metal (e.g., aluminum), it is preferred that the atomic ratio of divalent to trivalent metals in the spinel be in the range of about 0.17 to about 2.5, more preferably about 0.25 to about 2.0, and still more preferably about 0.35 to about 1.5.
• a divalent metal e.g., magnesium
• a trivalent metal e.g., aluminum
• the metal-containing spinels useful in the present invention may be derived from conventional and well known sources. For example, these spinels may be naturally occurring or may be synthesized using techniques well known in the art. Thus, a detailed description of such techniques is not included herein.
• a particularly useful process for preparing the VRS is presented in U.S.patent application Serial No. (Attorney Docket No. 15367), the specification of which is incorporated by reference herein.
• Substantially non-interfering proportions of other well known refractory material e.g., inorganic oxides such as silica, zirconia, thoria and the like may be included in the present VRS.
• substantially “non-interfering” is meant amounts of the material which do not have a substantial deleterious effect on the intended functionality of the present VRS, catalyst system, or hydrocarbon conversion process, as the case might be.
• the inclusion of materials such as silica, silica-alumina, zirconia, thoria and the like into the present VRS may act to improve one or more of the functions of the VRS.
• Free magnesia and/or alumina also may be included in the present VRS, e.g., using conventional techniques.
• the VRS preferably includes about 0.1% to about 30% by weight of free magnesia (calculated as MgO) .
• free magnesia may act to improve the effectiveness of the VRS to reduce sulfur oxide and/or nitrogen oxide atmospheric emissions.
• the rare earth metal component and the vanadium component may be associated with the spinel using impregnation, ion-exchange and the like, well known in the art. These metal components may be associated with the spinel together or in any sequence. Impregnation may be carried out by contacting the spinel with a solution, preferably an aqueous solution, of rare earth and vanadium salts. Water-soluble sources of rare earth and vanadium include the nitrate, acetate and chloride.
• the present VRS include about 0.1% to about 20%, more preferably about 0.1% to about 15%, and still more preferably about 2% to about 15%, by weight of rare earth metal, calculated as elemental metal; and about 0.05% to about 7%, more preferably about 0.1% to about 5%, and still more preferably about 0.2% to about 2% by weight of vanadium, calculated as elemental metal.
• the spinel can be dried and calcined to decompose the salts, forming an oxide in the case of nitrate or acetate.
• the spinel e.g., in the form of discrete particles, can be charged to a hydrocarbon conversion, e.g., cracking, unit with the rare earth and vanadium in salt form.
• the rare earth and vanadium salts with thermally decomposable anions can decompose to the oxides in the unit.
• the present discrete entities may further comprise a minor amount of at least one crystalline material capable of promoting the desired hydrocarbon conversion.
• Typical crystalline materials have been described above. Such crystalline materials may comprise about 1% to about 30%, for example about 1% to about 10%, by weight of the discrete entities. The presence of such crystalline materials in the present discrete entities acts to increase the overall catalytic activity of the solid particles-discrete entities mixture for promoting the desired hydrocarbon conversion.
• these metal components are substantially uniformly disposed in or on the VRS.
• rare earth metals useful in the present invention are the Lanthanum or Lanthanide Series (of the Periodic Chart of Elements) metals and mixtures thereof.
• the preferred rare earth metals are selected from the group consisting of cerium, praseodymium, lanthanum and mixtures thereof, with cerium being more preferred.
• the presently useful solid particles and discrete entities can be employed in a mass of combined particles which function as both the solid particles, e.g., promotes hydrocarbon conversion, and the discrete entities.
• Such combined particles may be produced in any suitable manner, certain of which methods are conventional and known in the art.
• the present catalyst i e., mixture comprising solid particles and discrete entities
• hydrocarbon conversion process find particular applicability in systems for the catalytic cracking of hydrocarbons where oxidative and regeneration of catalyst is employed.
• Such catalytic hydrocarbon cracking often involves converting, i.e., cracking, heavier or higher boiling components, to gasoline and other lower boiling components, such as hexane, hexene, pentane, pentene, butane, butylene, propane, propylene, ethane, ethylene, methane and mixtures thereof.
• the substantially hydrocarbon feedstock comprises a gas oil fraction, e.g., derived from petroleum, shale oil, tar sand oil, coal and the like.
• a gas oil fraction e.g., derived from petroleum, shale oil, tar sand oil, coal and the like.
• Such feedstock may comprise a mixture of straight run, e.g., virgin, gas oil.
• Such gas oil fractions often boil primarily in the range of about 400 degrees F. to about 1000 degrees F.
• Other substantially hydrocarbon feedstocks e.g., naphtha, high boiling or heavy fractions of petroleum, petroleum residuum, shale oil, tar sand oil, coal and the like, may be cracked using the catalyst and method of the present invention.
• Such substantially hydrocarbon feedstock often contains minor amounts of other elements, e.g., sulfur, nitrogen, oxygen and the like.
• the present invention involves converting a hydrocarbon feedstock containing sulfur and/or sulfur chemically combined with the molecules of hydrocarbon feedstock.
• the present invention is particularly useful when the amount of sulfur in such hydrocarbon feedstock is in the range of about 0.01% to about 5%, preferably about 0.1% to about 3%, by weight of the total feedstock.
• Hydrocarbon cracking conditions are well known and often include temperatures in the range of about 850 degrees F. to about 1100 degrees F., preferably about 900 degrees F. to about 1050 degrees F.
• Other reaction conditions usually include pressures of up to about 100 psia.; catalyst to oil ratios of about 1 to 2 to about 25 to 1, preferably about 3 to 1 to about 15 to 1; and weight hourly space velocities (WHSV) of about 3 to about 60.
• WHSV weight hourly space velocities
• the catalytic hydrocarbon cracking system includes a regeneration zone for restoring the catalytic activity of the solid particles or combined particles of catalyst previously used to promote hydrocarbon cracking.
• Carbonaceous, in particular sulfur-containing carbonaceous, deposit-containing catalyst particles from the reaction zone are contacted with free oxygen-containing gas in the regeneration zone at conditions to restore or maintain the activity of the catalyst by removing, i.e., combusting, at least a portion of the carbonaceous material from the catalyst particles.
• the carbonaceous deposit material contains sulfur
• at least one sulfur-containing combustion product is produced in the regeneration zone and may leave the zone with the regenerator flue gas.
• the conditions at which such free oxygen-containing gas contacting takes place may vary, for example, over conventional ranges.
• the temperature in the catalyst regeneration zone of a hydrocarbon cracking system are often in the range of about 900 degrees F. to about 1500 degrees F., preferably about 1100 degrees F. to about 1350 degrees F. and more preferably about 1100 degrees F. to about 1300 degrees F.
• Other conditions within such regeneration zone may include, for example, pressures up to about 100 psia., and average catalyst contact times within the range of about 3 minute to about 75 minutes.
• Sufficient oxygen is preferably present in the regeneration zone to completely combust the carbon and hydrogen of the carbonaceous deposit material, for example, to carbon dioxide and water.
• the amount of carbonaceous material deposited on the catalyst in the reaction zone is preferably in the range of about 0.005% to about 15%, more preferably about 0.1% to about 5% by weight of the catalyst.
• the amount of sulfur, if any, contained in the carbonaceous deposit material depends, for example, on the amount of sulfur in the hydrocarbon feedstock. This deposit material may contain about 0.01% to about 10% or more by weight of sulfur. At least a portion of the regenerated catalyst is often returned to the hydrocarbon cracking reaction zone.
• One embodiment of the present invention involves contacting sulfur oxide and/or nitrogen oxide-containing gases, e.g., combustion products, with the present VRS.
• sulfur oxide and/or nitrogen oxide-containing gases e.g., combustion products
• the present VRS Reduced concentrations of sulfur oxide and/or nitrogen oxide, e.g., reduced emissions of sulfur oxide and/or nitrogen oxide from the combustion zones, are achieved as a result of this contacting.
• Typical combustion zones include, for example, fluid bed coal burning steam boilers and fluid sand bed waste combustors.
• the present VRS may be added, either separately or with the sulfur-containing coal, to the combustion zone, e.g., boiler, where combustion takes place.
• the present VRS then leave the combustion zone with the coal ash and can be separated from the ash, e.g., by screening, density separation, or other well known solids separation techniques.
• the sulfur oxide-containing gases are contacted with the present VRS at conditions to reduce the sulfur oxide content of the gases in one or more zones, e.g., separate from the combustion zone.
• the flue gases leaving the combustion zone/contacting zone system have reduced amounts of sulfur oxide and/or nitrogen oxide, e.g., relative to processing in the absence of the present VRS.
• the VRS from the combustion zone or contacting zone can be subjected to a reducing environment, e.g., contacted with hydrogen, hydrocarbon and the like reducing media, at conditions such that at least a portion of the sulfur associated with the VRS is disassociated, e.g., in the form of hydrogen sulfide and is removed for further processing, e.g., sulfur recovery.
• the VRS, after sulfur removal may be recycled to the combustion zone or contacting zone.
• Conditions within such contacting zones may be those typically used in contact zones employing conventional sulfur oxide or nitrogen oxide removal agents.
• the amount of the present VRS used to contact a sulfur oxide-containing and/or nitrogen oxide-containing gas is sufficient to reduce the sulfur oxide and/or nitrogen oxide content of the gas, preferably, by at least about 50% and more preferably by at least 80%.
• Reducing conditions are such that at least a portion, preferably at least about 50% and more preferably at least about 80% of the sulfur associated with the VRS is removed.
• reducing conditions may include temperatures in the range of about 900 degrees F., hydrogen hydro 14 to abcarbon and the like, to associated sulfur mole ratio in the range of about 1 to about 10.
• a series of magnesium, aluminum-containing spinel compositions were prepared as follows.
• Magnesium, aluminum-containing spinel particles were prepared using conventional co-precipitation/calcining techniques.
• the resulting spinel had a surface area of more than 100m 2 /gm.; and an atomic ratio of magnesium to aluminum of 0.77.
• the average particle size of the spinel particles was in the range of about 65 microns.
• the spinel particles When two metals are included with the spinel particles, the spinel particles were impregnated with both metals simultaneously.
• the impregnation/calcining of the various portions of the spinel particles did not substantially change the surface area of the spinel or the size of the particles.
• Examples 15-28 A quantity of solid particles of a commercially available, crystalline aluminosilicate hydrocarbon cracking catalyst, having the same approximate particle size distribution as the spinel-containing particles from Examples 1 to 14, was combined with each of the final products of Examples 1 to 14 so that mixtures of 1.75 parts by weight of the spinel-containing particles (discrete entities) and 98.25 parts by weight of the solid particles resulted.
• the catalytic activity of the solid particles was equilibrated by use (prior to combining with the discrete entities ) in commercial fluid bed catalytic cracking service.
• Step 1 involved an initial determination of the ability of the blend to remove sulfur oxides from regenerator flue gases.
• Step one was carried out in a fluid bed catalytic cracking pilot plant known to provide results which are correlatable to results obtained in commercial sized systems.
• step 1 The feedstock and conditions for step 1 were as follows:
• Reactor temperature 1000 degrees F.
• Step 2 of the test procedure involved continuous and accelerated aging in a fluidized-bed reactor to simulate the type of aging which occurs in commercial fluid-bed catalytic cracking service.
• the feedstock and conditions utilized in step 2 were as follows: Feedstock - mid-continent gas oil containing 2% by weight sulfur
• Reactor temperature 1150 degrees F.
• Step 3 of the test procedure involved periodically repeating step 1 to determine how much of the blend's activity to remove sulfur oxide had been lost during the aging of step 2.
• the amount of total sulfur oxides emitted with the flue gases from the regeneration using the blend was used as the basis for determining the blend's ability (or activity) to remove such sulfur oxides.
• Example 10 Virgin 1 96
• Example 11 Virgin less than 25
• Example 13 Virginl 88
• Example 14 Virgin 47
• Example 14 Aged 2 days --
• composition 10 has both outstanding initial sulfur oxide removal activity and outstanding sulfur oxide removal activity stability, i . e . , the ability to maintain sulfur oxide removal activity over a period of time.
• Composition 10 Samples of virgin and aged Composition 10 were taken from a point between the reaction zone and the regeneration zone of the above-noted catalytic cracking pilot plant and were analyzed for sulfur content. It was found that the sulfur contents of these samples was significantly lower than those of other materials, such as Compositions 1, 2 and 3. Thus, it appears that the spinel-containing discrete entities of Composition 10 have reduced sulfur contents coming out of the reaction zone. This, in turn, means that Composition 10 has an increased kinetic driving force for sulfur oxide removal in the regeneration zone. In any event, the present vanadium, rare earth-containing spinel compositions do provide substantial sulfur oxide removal.
• This example illustrates the experimental trial of an embodiment of the present invention in a commercial-sized catalytic cracking unit.
• Magnesium, aluminum-containing spinel particles were prepared using a co-precipitation/ calcining technique.
• the resulting spinel had a surface area of more than 100m 2 /gm.; and an atomic ratio of magnesium to aluminum of 0.91.
• the average particle size of these spinel particles was in the range of about 65 microns.
• This spinel material was subjected to a conventional impregnation/calcining technique using an aqueous solution containing cerium (Ce(NO 3 ) 3 ) and vanadium ((NH 4 )VO 3 ) salts.
• the final spinel-containing particles included 10% by weight of cerium and 1% by weight of vanadium, calculated as the elemental metals.
• such FCC units involve a riser/vessel and a second vessel in at least limited fluid communication with each other.
• the riser/vessel serves as a reaction zone.
• Hydrocarbon feedstock and catalyst particles are fed to the riser/vessel reaction zone at hydrocarbon cracking conditions. At least a portion of the hydrocarbon cracking occurs in this reaction zone, where the catalyst and hydrocarbon form one or more fluid phases .
• Catalyst and hydrocarbon are continuously drawn from the reaction zone.
• the hydrocarbon is sent for further processing, distillation and the like.
• Catalyst, stripped of hydrocarbon flows to the second vessel, a catalyst regeneration zone, where it is combined with air at proper conditions to combust at least a portion of the carbonaceous deposits from the catalyst formed during the hydrocarbon cracking reaction.
• the catalyst and vapors in the regeneration zone form a fluid phase or bed.
• Catalyst is continuously removed from the regeneration zone and is combined with the hydrocarbon feedstock prior to being fed to the reaction zone.
• the weight ratio of catalyst particles (including the final spinel-containing particles noted above) to total (fresh plus recycle) hydrocarbon feed entering the reaction zone was about 6 to 1.
• Other typical conditions within the reaction zone include:
• the catalyst particles from the reaction zone included about 0.8% by weight of carbonaceous deposit material which was at least partially combusted in the regeneration zone.
• This carbonaceous material also included a minor amount of sulfur which forms SO 2 at the combustion conditions formed in the regeneration zone.
• Air in an amount so that amount of oxygen in the regeneration zone was about 1.15 times the amount theoretically required to completely combust this deposit material, was heated to the desired temperature before being admitted to the regeneration zone.
• the effectiveness of the present spinel-containing particles in reducing sulfur oxide emissions is substantially greater than with certain other spinel-containing particles.
• a concentration level in the FCC unit catalyst inventory of 0.75% by weight is required.
• the present compositions which include both rare earth metal and vanadium are clearly superior. Examples 30-34 These Examples illustrate certain preferred embodiments of the present invention
• Magnesium, aluminum-containing spinel particles were prepared using a co-precipitation/calcining technique.
• the resulting spinel had a surface area of more than 100m 2 /gm. and an atomic ratio of magnesium to aluminum of about 0.5.
• the average particle size of the spinel particles was in the range of bout 65 microns.
• each of these spinel-containing compositions was combined with a quantity of commercially available hydrocarbon cracking catalyst particles described above in Examples 15 to 28 so that mixtures of 1.75 parts by weight of the spinel-containing composition and 98.25 parts by weight of the cracking catalyst particles results.
• Each of these blends was tested to determine its ability to reduce the nitrogen oxide (NOx) content of the flue gases from a cracking catalyst regeneration zone.
• NOx nitrogen oxide
• each of these blends was subjected to twenty two reaction/ regeneration cycles using step (2) of the test procedure set forth above in Examples 15 to 28. After this aging, the blend was tested in accordance with step (l) of the above-noted test procedure and the nitrogen oxide content of the regeneration zone flue gases was measured. Results of these tests were as follows:
• compositions which include rare earth metal component and vanadium component do provide for reduction in nitrogen oxide emissions from combustion zone flue gases.
• Such compositions which include about 0.2% to about 2%, more particularly about 0.5% to about 1.5%, by weight of vanadium component (calculated as elemental vanadium) provide outstanding reductions in such nitrogen oxide emissions.

Landscapes

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

Applications Claiming Priority (2)

Publications (1)

Family

ID=25304886

Family Applications (1)

Country Status (5)

Families Citing this family (14)

Family Cites Families (3)

• 1987
  • 1987-04-07 JP JP50242787A patent/JPH01500571A/ja active Pending
  • 1987-04-07 AU AU72863/87A patent/AU7286387A/en not_active Abandoned
  • 1987-04-07 WO PCT/US1987/000749 patent/WO1987006156A1/en not_active Application Discontinuation
  • 1987-04-07 BR BR8707259A patent/BR8707259A/pt unknown
  • 1987-04-07 EP EP19870903034 patent/EP0263170A1/de not_active Withdrawn

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events