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
  • C10G11/02—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
• • 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

Definitions

• the present invention relates to catalytic cracking catalysts, and more specifically to cracking catalyst compositions which are particularly effective for the cracking of residual type hydrocarbon feedstocks.
• Zeolite containing cracking catalysts in particular are susceptable to deactivation (poisoning by vanadium) and in addition the catalytic selectivity of the catalyst is adversely affected by the presence of iron, copper and nickel.
• U.S. 3,835,031 and U.S. 4,240,899 describe cracking catalysts which are impregnated with Group IIA metals for the purpose of reducing sulfur oxide emissions during regeneration of the catalyst.
• U.S. 3,409,541 describes catalytic cracking processes wherein deactivation of the catalyst by contaminating metals is decreased by adding to the catalytic inventory a finely divided alkaline earth or boron type compound which reacts with the metal contaminants to form an inert product that may be removed from the catalytic reaction system.
• U.S. 3, 699,037 discloses a catalytic cracking process wherein a finely divided additive such as calcium and magnesium hydroxides, carbonates, oxides, dolomite and/or limestone is added to the catalyst inventory to sorb SO x components present in the regenerator flue gas.
• a finely divided additive such as calcium and magnesium hydroxides, carbonates, oxides, dolomite and/or limestone is added to the catalyst inventory to sorb SO x components present in the regenerator flue gas.
• U.S. 4,198,320 describes catalytic cracking catalysts which contain colloidal silica and/or alumina additives that are added for the purpose of preventing the deactivation of the catalyst when used to process metals containing feedstocks.
• U.S. 4,222,896 describes a metals tolerant zeolite cracking catalyst which contain a magnesia-alumina-aluminum phosphate matrix.
• U.S. 4,283,309 and 4,292,169 describe hydrocarbon conversion catalysts which contain a metals-absorbing matrix that includes a porous inorganic oxide such as alumina, titania, silica, circonia, magnesia and mixtures thereof.
• U.S. 4,465,779 discloses cracking catalyst compositions which comprise a high activity catalytic cracking catalyst and as a separate and distinct entity a magnesium compound or magnesium compond in combination with a heat stable compound.
• U.S. 4,432,890 and 4,469,588 disclose catalytic cracking catalyst compositions which are used to crack hydrocarbon oild feedstocks that contain significant quantities of vanadium which comprise a zeolite and an amorphous invert solid matrix containing a metal additive such as magnesium which may be introduced into the catalyst during manufacture or during use in the conversion of hydrocarbons.
• PCT WO 82/00105 discloses cracking catalysts that are resistant to metals poisoning which comprise two particulate size fractions, and an SO x absorbing additive such as aluminum oxide, calcium oxide and/or magnesium oxide.
• FCC fluid cracking catalysts
• the invention contemplates catalytic cracking catalysts which include a basic alkaline earth metal component in amounts ranging from about 5 to 80 weight percent expressed as the oxides, wherein the catalyst is capable of maintaining a high degree of activity when associated with substantial quantities of deactivating metals such as vanadium deposited on the catalyst.
• the alkaline earth metal compound used in the practice of the invention is selected from group IIA of the periodic Table with calcium and magnesium being preferred and magnesium the most preferred.
• the basic alkaline earth metal component comprises MgO or magnesia-silica gels and a significant pore volume in pores greater than about 400 A° at process temperatures of 1400°F or so.
• a magnesium oxide containing component such as a magnesia-silica gel (MgO.SiO2) is prepared in a particulate form wherein the particle has a substantial pore volume in pores having a diameter of greater than about 400°A.
• the resulting MgO.SiO2 composition is included in a FCC catalyst composition either as an integral component of the FCC catalyst particle or more preferably as a separate particulate additive in amounts ranging from about 2.5 to 40 by weight of the composition.
• the preferred MgO.SiO2 gel has the overall weight composition of 30-80% MgO, and a pore volume in pores greater than about 400°A diameter of at least 0.1 cc/g and preferably from about 0.2 to 1.0 cc/g.
• the particle size and density of the additive is preferably similar to that of the FCC catalyst, i.e. particle size range of about 40 to 80 microns and an average bulk density of 0.5 to 1.0 g/cc.
• a preferred MgO.SiO2 gel is prepared by reacting aqueous sodium silicate and magnesium chloride solutions at a temperature of about 15 to 50°C to form a precipitate gel whch is recovered by filtration, reslurried in water and spray dried at a temperature of about 330 to 500°C. Furthermore, particulate MgO can be added to the MgO.SiO2 gel to give composition of 30-80% MgO to the final product.
• the MgO containing catalyst component must have the optimized pore structure described above in order to be effective for vanadium scavenging. This is due to the fact that partial molar volume of magnesium vanadate is greater than magnesium oxide. It is believed that the vanadium poisoning of cracking catalysts is caused by the poison precursor H3VO4 which is formed in the regeneration step from the reaction of V2O5 and steam (for vapor pressure data see L.N. Yannopoulos, J. Phys. Chem. 72 , 3293 (1968). H3 VO4 is isoelectronic with H3PO4 and is most probably a strong acid.
• H3VO4 therefore destroys the zeolite crystallanity and activity by acid hydrolysis of the SiO2-Al2O3 framework of the zeolite.
• H3VO4 reacts with MgO and forms (MgO)2V2O5 on the surface of pore, the surface of the pore will swell due to larger molar volume of (MgO)2V2O5. If the pore is too small, blocking will occur readily and thereby inhibit the further reaction with H3VO4.
• the average pore diameter must be greater than 400°A or so to be effective. This effect has been extensively studied with similar reaction: CaO + SO3 ---- ⁇ CaSO4 (see S.K. Bhatia and D. D. Perlmutter AIChE J. 27 , 266 and 29 , 79).
• MgO is the preferred oxide over the other alkaline earths when used in conjunction with FCC catalysts. This is due to the presence of sulfur oxides in the flue gases of the regenerator, which can compete with H3VO4 forming alkaline earth SO4's as shown by a consideration of the equilibrium constants for the reactions of MgSO4 and CaSO4 with vanadic acid.
• thermochemical data Assuming a worst case test in which all of the SO x is assumed to be SO3 at a typical level of 2000 ppm in the regenerator, 20% H2, 1.07 ppm H3VO4 and a temperature of 970°K (1285°F) a calculated equilibrium constant (assuming unit activity for the condensed phases) from the regenerator conditions above can be compared to the equilibrium constant for the two reactions from thermochemical data as follows:
• the fluid catalytic cracking catalysts which are combined with the basic alkaline earth metal component, are conventional and well known to those skilled in the art.
• the catalysts comprise amorphous inorganic oxide gels such as silica-alumina hydrogels, and/or a crystalline zeolite dispersed in an inorganic oxide matrix.
• Preferred zeolites are synthetic faujasite (type Y zeolite) and/or shape selective zeolites such as ZSM-5.
• Type Y zeolites which are exchanged with hydrogen and/or rare earth metals such as HY and REY, and those which have been subjected to thermal treatments such as calcined, rare-earth exchanged Y (CREY) and/or Z14US are particularly suited for inclusion in fluid cracking catalyst compositions.
• Catalytically active zeolite components are typically described in U.S. patents 3,293,192 and RE 28,629.
• the catalysts contain an inorganic oxide matrix.
• the inorganic oxide matrix is typically a silica-alumina hydrogel, which may be combined with substantial quantities of clay such as kaolin.
• clay such as kaolin.
• catalyst matrix systems which comprise silica, alumina, silica-alumina sols and gels may be utilized in the practice of the present invention. Methods for producing suitable catalyst compositions are described in U.S. 3,974,099, 3,957,689, 4,226,743, 3,867,308, 4,247,420, and U.S. Serial No. 361,426 filed March 24, 1982.
• the basic alkaline earth metal component may be added to the catalyst composition in the form of a finely divided particulate solid or the component may be added in the form of a salt which is subsequently converted to a solid oxide.
• Magnesium and calcium oxides, hydroxides, carbonates or sulfates are particularly suited forms of the basic alkaline earth metal components which are added to the catalyst either during or after manufacture.
• the basic alkaline earth containing component is physically admixed with the particulate catalyst.
• the alkaline earth metal component is included in the catalyst composition (matrix) during manufacture.
• the alkaline earth metal component is added to the zeolite containing catalyst in a form that does not ion exchange with the zeolite component.
• a finely divided alkaline earth metal component is blended with an aqueous slurry which contains silica-alumina hydrogel, optimally a zeolite, and clay to obtain a pumpable slurry which is then spray dried to obtain microspheroidal particles of catalyst having a particle size ranging from about 20 to 100 microns.
• the spray dried catalyst which typically contains from about 0 to 35 percent by weight zeolite, 25 to 70 percent by weight clay, and 10 to 50 percent by weight matrix binder, such as silica, alumina, silica-alumina hydrogel or sol, and from 5 to 80 percent by weight alkaline earth metal component, is washed and ion exchanged to remove soluble impurities such as sodium and sulfates. After drying to about 10-30 percent total volatiles the catalyst is ready to be used in conventional catalytic cracking processes. Typical FCC processes involve contact of the catalyst with a hydrocarbon feedstock which may contain significant quantities, i.e. from 1 to 200 ppm of vanadium and other metals such as nickel, iron and copper at temperatures on the order of 900 to 1000°F to obtain cracked products of lower molecular weight such as gasoline and light cycle oil.
• the catalysts contemplated in the present invention can sorb in excess of 0.1 percent and up to 10 percent by weight of metals, particularly vanadium, while maintaining an acceptable level of activity and product selectivity.
• Typical "conventional" catalysts which do not contain the alkaline earth metal component contemplated herein, lose substantial activity when the metals content (vanadium in particular) exceeds about 0.1 weight percent.
• a magnesia-silica gel was prepared by mixing a 3.62% SiO2 and 10.87% NaOH aqueous solution with 13.28% MgCl2 aqueous solution at equal flow rates through a mix pump to form a MgO.SiO2 gel with composition 60 wt.% MgO 40 wt.% SiO2.
• the temperature of the reaction mixture was 30°C for example A to make smaller pore diameters, and 20°C for example B for larger pore diameters.
• the resultant gel in both cases was filtered, reslurried in water to ⁇ 10% solids and spray dried at 330°C. The spray dried material was washed with 70°C H2O to remove NaCl. Both preps were calcined for 2 hours at 538°C.
• Two catalyst samples were prepared by blending 20 % by weight of additive A or B with 80 % by weight of a commercial FCC catalyst (Super D).
• the so ob­tained catalyst samples were impregnated to a level of 0.67 wt % vanadium, using a solution which con­tained vanadyl oxylate dissolved in water.
• the samples were then pre-heated at 900°F for 1 hour and then 2 hours at 1400°F.
• the catalyst samples were then subjected to a hydrothermal deactivation treatment which involved contacting the catalyst with 100 % steam at a pressure of 2 atm at 1350°F for 8 hours.
• the catalysts of this Example (as well as the cata­lysts evaluated in Example 2) were then tested for catalytic cracking activity using the microactivity test described in ASTM D-3907.
• the microactivity (MA) of the catalyst samples is expressed in terms of volume percent (vol%) of feedstock converted. The results are summarized in Table I set forth below.
• Catalyst A is a blend of 80 % Super D, 20% commercially available high pore volume MgO (from Martin Marietta grade Mag-Chem-30).
• Catalyst B is a blend of 80% Super D, 20% commercially available low pore volume MgO (from Martin Marietta grade Mag-Chem 10). Both catalysts are impregnated by the procedure in Example 1. Table VI shows the microactivity results.

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• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
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• 1986
  • 1986-04-30 JP JP61098418A patent/JPS61278351A/ja active Pending
  • 1986-05-15 DE DE8686106616T patent/DE3668903D1/de not_active Expired - Lifetime
  • 1986-05-15 AT AT86106616T patent/ATE50280T1/de active
  • 1986-05-15 EP EP86106616A patent/EP0208868B1/fr not_active Expired - Lifetime
  • 1986-05-26 AU AU57908/86A patent/AU584424B2/en not_active Ceased
  • 1986-05-30 ES ES555498A patent/ES8802177A1/es not_active Expired

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