EP0147961B1 - Passivation von Krackkatalysatoren - Google Patents

Passivation von Krackkatalysatoren Download PDF

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Publication number
EP0147961B1
EP0147961B1 EP19840308521 EP84308521A EP0147961B1 EP 0147961 B1 EP0147961 B1 EP 0147961B1 EP 19840308521 EP19840308521 EP 19840308521 EP 84308521 A EP84308521 A EP 84308521A EP 0147961 B1 EP0147961 B1 EP 0147961B1
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EP
European Patent Office
Prior art keywords
passivation
zone
catalyst
cracking
cadmium
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EP19840308521
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English (en)
French (fr)
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EP0147961A2 (de
EP0147961A3 (en
Inventor
Carl Franklin Bertsch
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ExxonMobil Technology and Engineering Co
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Exxon Research and Engineering Co
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Priority claimed from US06/559,918 external-priority patent/US4504381A/en
Priority claimed from US06/559,891 external-priority patent/US4522704A/en
Application filed by Exxon Research and Engineering Co filed Critical Exxon Research and Engineering Co
Publication of EP0147961A2 publication Critical patent/EP0147961A2/de
Publication of EP0147961A3 publication Critical patent/EP0147961A3/en
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    • 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
    • C10G11/187—Controlling or regulating
    • 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
    • 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

Definitions

  • the present invention is directed at a process for catalytic cracking of hydrocarbon feedstocks. More specifically, the present invention is directed at a method for reducing the detrimental effects of metal contaminants such as nickel, vanadium and/or iron, which typically are present in the hydrocarbon feedstock processed and are deposited on the cracking catalyst.
  • the term "passivation" is defined as a method for decreasing the detrimental catalytic effects of metal contaminants such as nickel, vanadium and/or iron which become deposited on the cracking catalyst.
  • European Patent Publication No. 1,642; U.S. Patent Nos. 4,257,919; 4,326,990; and 4,324,648 also disclose the use of tin for metals passivation. These patent publications also disclose the sequential use of a reducing atmosphere at elevated temperature and the use of a hydrogen atmosphere at elevated temperature to simulate aging of the catalyst prior to testing. U.S. Patent No. 4,235,704 also discloses the use of tin for decreasing the adverse catalytic activity of metal contaminants.
  • U.S. Patent No. 2,575,258 discloses the addition of a reducing agent to regenerated catalyst at a plurality of locations in the transfer line between the regeneration zone and the cracking zone for countercurrent flow of the reducing gas relative to the flow of the regenerated catalyst.
  • This patent also discloses the addition of steam to the transfer line downstream of the points at which reducing gas is added to the transfer iine to assist in moving regenerated catalyst from the regeneration zone to the reaction zone.
  • Countercurrent flow of the reducing gas relative to the catalyst flow is not desirable, particularly at relatively high catalyst circulation rates, since the catalyst and reducing gas will tend to segregate into two oppositely flowing phases. This would result in poor catalyst contacting.
  • bubbles of countercurrently flowing reducing gas intermittently could interrupt the recirculation of the catalyst.
  • European Patent Publication No. 52,356 also discloses that metal contaminants can be passivated utilizing a reducing atmosphere at an elevated temperature. This publication discloses the use of reducing gases for passivating regenerated catalyst before the catalyst is returned to the reaction zone. This publication also discloses that the contact time of the reducing gas with the catalyst may range between 3 seconds and 2 hours, preferably between about 5 and 30 minutes. This patent publication further discloses that the degree of passivation is improved if antimony is added to the cracking catalyst.
  • U.S. Patent No. 4,377,470 discloses a process for catalytic cracking of a hydrocarbon feed having a significant vanadium content. Reducing gas may be added to the regenerator and to the transfer line between the regenerator and the reactor to maintain the vanadium in a reduced oxidation state.
  • U.S. Patent Nos. 4,298,459 and 4,280,898 describe processes for cracking a metals-containing feedstock where the used cracking catalyst is subjected to alternate exposures of up to 30 minutes of an oxidizing zone and a reducing zone maintained at an elevated temperature to reduce the hydrogen and coke makes. These patents describe the use of a transfer line reaction zone disposed between a regeneration zone and a stripping zone.
  • the '898 patent discloses that a metallic reactant, such as cadmium, zinc, sodium, scandium, titanium, chromium, molybdenum, manganese, cobalt, nickel, antimony, copper, the rare earth metals, and compounds of these metals may be added to adsorb the sulfur oxides produced.
  • U.S. Patent Nos. 4,280,859; 4,280,896; 4,370,220; 4,372,840; 4,372,841; and 4,409,093 disclose that cracking catalyst can be passivated by passing the catalyst through a passivation zone, having a reducing atmosphere maintained at an elevated temperature for a period of time ranging from 30 seconds to 30 minutes, typically from about 2 to 5 minutes.
  • U.S. Patent No. 4,268,416 also describes a method for passivating cracking catalyst in which metal contaminated cracking catalyst is contacted with a reducing gas at elevated temperatures to passivate the catalyst.
  • U.S. Patent No. 3,408,286 discloses the addition of a liquid hydrocarbon to regenerated catalyst under cracking conditions in a transfer line before the regenerated catalyst is recharged to the cracking zone.
  • the cracking of the liquid hydrocarbon prior to entering the cracking zone operates to displace entrained regenerator gases from the regenerated catalyst entering the cracking zone.
  • U.S. Patent No. 2,901,419 discloses the use of additives selected from groups III and IV of the Periodic Table, preferably from the right side sub-groups or from the right side sub-groups of groups I and II.
  • Preferred compounds include copper, silver, gold, zinc, cadmium and mercury and compounds of these metals. Included in the specifically disclosed compounds were cadmium fluoride, cadmium formate, cadmium oxalate and cadmium oxide.
  • the group III metals include indium, while the group IV metals include germanium.
  • WO 82/03225 and WO 82/03226 disclose the use of several metals, their oxides and salts, and their organometallic compounds to immobilize vanadium in a catalytic cracking operation.
  • the metals include indium, tellurium, magnesium, calcium, strontium, barium, scandium, yttrium, lanthanum, titanium, zirconium, hafnium, niobium, tantalum, manganese, iron, thallium, bismuth, the rare earths and the Actinide and Lanthanide series of elements.
  • U.S. Patent No. 4,386,015 discloses the use of germanium and germanium compounds to passivate metal contaminants in a catalytic cracking operation.
  • U.S. Patent No. 4,238,317 is directed at a method for decreasing the carbon monoxide and sulfur oxide emissions from a catalytic cracking system.
  • a metallic oxidation promoter may be used to oxidize the carbon monoxide and sulfur oxides.
  • the oxidation promoter may include cadmium, zinc, magnesium, strontium, barium, scandium, titanium, chromium, molybdenum, manganese, cobalt, nickel, antimony, copper, lead, the rare earth metals, and compounds thereof.
  • U.S. Patent No. 4,257,919 discloses the use of indium, tin, bismuth, and compounds thereof for passivating metal contaminants.
  • U.S. Patent Nos. 4,169,042 (EP-A-0 049 091) and 4,218,337 disclose the use of elemental tellurium, tellurium oxides, and compounds convertible to elemental tellurium, or tellurium oxide to passivate the adverse catalytic effects of metal contaminants.
  • the present invention is directed at a method for increasing the rate of metal contaminant passivation in a passivation zone disposed in a cracking system by the addition to the cracking system of a passivation promoter.
  • the passivation promoter is selected from the group consisting of cadmium-tin mixtures, cadmium, germanium, indium, tellurium, zinc, and mixtures thereof.
  • the present invention is directed to a process for passivating cracking catalyst in a cracking system comprising a reaction zone, a regeneration zone, and a passivation zone, wherein a hydrocarbon feedstock containing a metal contaminant selected from the group consisting of nickel, vanadium, iron and mixtures thereof is passed into a reaction zone of said cracking system containing therein a cracking catalyst to produce cracked products and cracking catalyst contaminated with deposited coke and said metals, said coke being removed from said cracking catalyst in a regeneration zone from which at least a portion of the said coke depleted metal contaminated cracking catalyst is circulated to said reaction zone through a passivation zone maintained under passivation conditions prior to returning said catalyst to said reaction zone, said process being characterized by the step of adding an effective amount of a passivation promoter to the cracking system, said passivation promoter being selected from the group of metals consisting of cadmium-tin mixtures, cadmium, germanium, indium, tellurium, zinc,
  • the passivation zone is disposed at least partially in the transfer zone communicating with the regeneration zone and reaction zone.
  • the temperature in the transfer zone preferably is maintained in the range of about 700°C to about 850°C.
  • the concentration of the passivation promoter in the system preferably is maintained between about 0.005 and about 0.20 weight percent of the cracking catalyst present in the cracking system, and more preferably within the range of about 0.025 and about 0.10 weight percent.
  • Particularly preferred passivation promoters comprise cadmium-tin, germanium, zinc, cadmium, and compounds thereof, with cadmium and cadmium compounds being most preferred.
  • the residence time of the catalyst in the passivation zone preferably is maintained between about 0.1 and about 20 minutes, more preferably between about 0.5 and about 2 minutes.
  • Passivation promoter preferably is added to the feed or deposited on the catalyst, with the more preferred method comprising the addition of the promoter with the feed.
  • Reaction or cracking zone 10 containing a fluidized catalyst bed 12 having a level at 14 in which a hydrocarbon feedstock is introduced into the fluidized bed through line 16 for catalytic cracking.
  • the hydrocarbon feedstock may comprise naphthas, light gas oils, heavy gas oils, residual fractions, reduced crude oils, cycle oils derived from any of these, as well as suitable fractions derived from shale oil, kerogen, tar sands, bitumen processing, synthetic oils, coal, hydrogenation, and the like.
  • feedstocks may be employed singly, separately in parallel reaction zones, or in any desired combination.
  • these feedstocks will contain metal contaminants such as nickel, vanadium and/or iron.
  • Heavy feedstocks typically contain relatively high concentrations of vanadium and/or nickel. Hydrocarbon gas and vapors passing through fluidized bed 12 maintain the bed in a dense, turbulent, fluidized condition.
  • the cracking catalyst becomes spent during contact with the hydrocarbon feedstock due to the deposition of coke thereon.
  • the terms "spent” or “coke-contaminated” catalyst as used herein generally refer to catalyst which has passed through a reaction zone and which contains a sufficient quantity of coke thereon to cause activity loss, thereby requiring regeneration.
  • the coke content of spent catalyst can vary anywhere from about 0.5 to about 5 wt.% or more.
  • spent catalyst coke contents vary from about 0.5 to about 1.5 wt.%.
  • the spent catalyst Prior to actual regeneration, the spent catalyst is usually passed from reaction zone 10 into a stripping zone 18 and contacted therein with a stripping gas, which is introduced into the lower portion of zone 18 via line 20.
  • the stripping gas which is usually introduced at a pressure of from about 10 to 50 psig, serves to remove most of the volatile hydrocarbons from the spent catalyst.
  • a preferred stripping gas is steam, although nitrogen, other inert gases or flue gas may be employed.
  • the stripping zone is maintained at essentially the same temperature as the reaction zone, i.e., from about 450°C to about 600°C.
  • Stripped spent catalyst from which most of the volatile hydrocarbons have been removed is then passed from the bottom of stripping zone 18 through U-bend 22 and connecting vertical riser 24, which extends into the lower portion of a regeneration zone. Air is added to riser 24 via line 28 in an amount sufficient to reduce the density of the catalyst flowing therein, thus causing the catalyst to flow upwardly into regeneration zone 26 by simple hydraulic balance.
  • regeneration zone 26 is a separate vessel (arranged at approximately the same level as reaction zone 10) containing a dense phase catalyst bed 30 having a level indicated at 32, which is undergoing regeneration to burn-off coke deposits formed in the reaction zone during the cracking reaction, above which is a dilute catalyst phase 34.
  • An oxygen-containing regeneration gas enters the lower portion 31 of regeneration zone 26 via line 36 and passes up through a grid 38 in the dense phase catalyst bed 30, maintaining said bed in a turbulent fluidized condition similar to that present in reaction zone 10.
  • Oxygen-containing regeneration gases which may be employed in the process of the present invention are those gases which contain molecular oxygen in admixture with a substantial portion of an inert diluent gas. Air is a particularly suitable regeneration gas.
  • An additional gas which may be employed is air enriched with oxygen. Additionally, if desired, steam may be added to the dense phase bed along with the regeneration gas or separately therefrom to provide additional inert diluents and/or fluidization gas.
  • the specific vapor velocity of the regeneration gas will be in the range of from about 0.8 to about 6.0 feet/sec., preferably from about 1.5 to about 4 feet/sec.
  • flue gases formed during regeneration of the spent catalyst pass from the dense phase catalyst bed 30 into the dilute catalyst phase 34 along with entrained catalyst particles.
  • the catalyst particles are separated from the flue gas by a suitable gas-solid separation means 54 and returned to the dense phase catalyst bed 30 via diplegs 56.
  • the substantially catalyst-free flue gas then passes into a plenum chamber 58 prior to discharge from the regeneration zone 26 through line 60.
  • the flue gas typically will contain less than about 0.2, preferably less than 0.1 and more preferably less than 0.05 volume % carbon monoxide.
  • the oxygen content usually will vary from about 0.4 to about 7 vol.%, preferably from about 0.8 to about 5 vol.%, more preferably from about 1 to about 3 vol.%, most preferably from about 1.0 to about 2 vol.%.
  • Regenerated catalyst exiting from regeneration zone 26 preferably has had a substantial portion of the coke removed.
  • the carbon content of the regenerated catalyst will range from about 0.01 to about 0.6 wt.%, preferably from about 0.01 to about 0.1 wt.%.
  • the regenerated catalyst from the dense phase catalyst bed 30 in regeneration zone 26 flows through a transfer zone comprising standpipe 42 and U-bend 44 to reaction zone 10.
  • passivation zone 90 extends for substantially the entire length of standpipe 42 and U-bend 44 to gain substantially the maximum possible residence time. If a shorter residence time is desired, passivation zone 90 could comprise only a fraction of the length of standpipe 42 and/or U-bend 44. Conversely, if a greater residence time were desired, the crosssectional area of standpipe 42 and/or U-bend 44 could be increased.
  • Stripping gas streams optionally may be added at the inlet of passivation zone 90 to minimize the intermixing of regeneration zone gas with the passivation zone reducing gas.
  • the stripping gas may be any non-oxidizing gas, such as steam, which will not adversely affect the passivated catalyst and which will not hinder the processing of the feedstock in the reaction zone.
  • line 92 is disposed upstream of passivation zone 90, to minimize intermixing of the reducing atmosphere in passivation zone 90 with the gas stream from regeneration zone 26 by stripping out entrained oxygen from the regenerated catalyst.
  • the catalyst residence time in standpipe 42 and U-bend 44 typically may range only from about 0.1 to about 2 minutes, it may be necessary to increase the rate at which the metal contaminant present on the cracking catalyst is passivated. It has been found that the addition of passivation promoters selected from the group consisting of cadmium-tin mixtures, cadmium, germanium, indium, tellurium, zinc, compounds thereof and mixtures thereof increases the rate of passivation of the metal contaminants, particularly where the residence time of the cracking catalyst in a passivation zone is less than about 5 minutes. The combination of cadmium-tin increases the passivation of the metal contaminants above that which would be realized with comparable quantities of cadmium or tin alone.
  • Control valve 72 is shown being regulated by a cracked product monitoring means, such as analyzer 82.
  • Analyzer 82 may be adapted to monitor the content of one or more products in stream 52. Since the hydrogen content of the cracked product is a function of the degree of catalyst metals passivation, in a preferred embodiment, analyzer 82 may be a hydrogen analyzer. Alternatively, since the rate of coke production also is a function of the degree of catalyst metals passivation, the rate of reducing gas addition also could be regulated by monitoring the rate of coke production. This may be accomplished by monitoring the heat balance around reaction zone 10 and/or regeneration zone 26.
  • the rate of addition of reducing gas to passivation zone 90 also must be maintained below the point at which it will cause a significant fluctuation in the catalyst circulation rate.
  • the rate of catalyst circulation through passivation zone 90 may be monitored by a sensing means, such as sensor 84, shown communicating with regeneration zone 26, standpipe 42 and control valve 72.
  • the concentration of hydrogen in product stream 52 may be monitored by analyzer 82, which adjusts the rate of addition of reducing gas through control valve 72 to minimize the hydrogen content in stream 52.
  • Sensor 84 operates as a limit on control valve 72, by decreasing the rate of addition of reducing gas to passivation zone 90, when the rate of addition of reducing gas begins to adversely affect the catalyst circulation rate.
  • riser reaction zone 110 comprises a tubular, vertically extending vessel having a relatively large height in relation to its diameter.
  • Reaction zone 110 communicates with a disengagement zone 120, shown located a substantial height above regeneration zone 150.
  • the catalyst circulation rate is controlled by a valve means, such as slide valve 180, located in spent catalyst transfer line 140, extending between disengagement zone 120 and regeneration zone 150.
  • hydrocarbon feedstock is injected through line 112 into riser reaction zone 110 having a fluidized bed of catalyst to catalytically crack the feedstock.
  • Steam may be injected through lines 160 and 162 in a second transfer zone, such as return line 158, extending between regeneration zone 150 and reaction zone 110 to serve as a diluent, to provide a motive force for moving the hydrocarbon feedstock upwardly and for keeping the catalyst in a fluidized condition.
  • a second transfer zone such as return line 158
  • the vaporized, cracked feedstock products pass upwardly into disengagement zone 120 where a substantial portion of the entrained catalyst is separated.
  • the gaseous stream then passes through a gas-solid separation means, such as two stage cyclone 122, which further separates out entrained catalyst and returns it to the disengagement zone through dilegs 124,126.
  • the gaseous stream passes into plenum chamber 132 and exits through line 130 for further processing (not shown).
  • the upwardly moving catalyst in reaction zone 110 gradually becomes coated with carbonaceous material which decreases its catalytic activity.
  • Flue gas formed during the regeneration of the spent catalyst passes from the dense phase catalyst bed 152 into dilute catalyst phase 154.
  • the flue gas then passes through cyclone 170 into plenum chamber 172 prior to discharge through line 174.
  • Catalyst entrained in the flue gas is removed by cyclone 170 and is returned to catalyst bed 152 through diplegs 176, 178.
  • a passivation zone such as passivation zone 190, may be disposed in or may comprise substantially all of overflow well 156 and/or return line 158. If passivation zone 190 comprises substantially all of return line 158, the fluidizing gas injected through lines 160 and 162 may comprise reducing gas. To avoid excess reducing gas consumption while providing sufficient quantities of gas to adequately fluidize the regenerated particles in line 158, it may be desirable to dilute the reducing gas with stream and/or other diluent gas added through lines 160 and 162.
  • the residence time of catalyst in overflow well 156 and return line 158 typically ranges between about 0.1 and about 1 minute. Here also it may be necessary to increase the rate at which metal contaminant on the catalyst is passivated. As shown for the embodiment of Figure 1, it may be desirable to add a stripping gas, such as stream through line 192 to overflow well 156 to remove entrained oxygen from the regenerated catalyst.
  • the reducing gas preferably is added to passivation zone 190 at a plurality of locations through branched lines, such as lines 202, 204, 206, 208 and 210 extending from reducing gas header 200.
  • a control means such as control valve 220 is disposed in reducing gas header 200 to regulate the rate of addition of reducing gas to passivation zone 190.
  • a cracked product monitoring means such as analyzer 230 is shown communicating with cracked product line 130 and with control valve 220 to maintain the sampled cracked product component within the desired limits by regulation of the rate of addition of reducing gas to passivation zone 190. Since hydrogen is one of the products produced by the adverse catalytic properties of the metal contaminants, hydrogen may be the preferred component to be regulated.
  • the rate of reducing gas addition also could be regulated by the monitoring of the rate of coke production, such as by monitoring the heat balance around regeneration zone 150, as previously described.
  • the rate of catalyst circulation may be monitored by a sensing means, such as sensor 240, communicating with valve 220, to control the maximum rate of addition of reducing gas to passivation zone 190.
  • a component in the product stream, such as hydrogen is monitored by analyzer 230, which directs control valve 220 to adjust the rate of addition of reducing gas to passivation zone 190, such as to minimize the hydrogen content in stream 130.
  • Sensor 240 monitors the catalyst circulation rate and operates as an over-ride on control valve 220, to reduce the rate of addition of reducing gas if the reducing gas has, or is about to have, an adverse effect on the catalyst circulation rate.
  • the metals concentration deposited on the catalyst is not believed to differ significantly whether the embodiment of Figure 1 or the embodiment of Figure 2 is used.
  • the amount of reducing gas which is consumed in passivation zones 90,190 of the embodiments of Figures 1, 2, respectively, and the amount of passivation promoter which is added should not differ greatly. Since the catalyst must be fluidized in the embodiment of Figure 2, and need not be fluidized in the embodiment of Figure 1, it is more likely that, in practicing the embodiment of Figure 2, a diluent gas will be added with reducing gas to passivation zone 190 to fluidize the catalyst.
  • the rate of addition of the passivation promoter will be a function, in part, of the residence time of the cracking catalyst in the passivation zone, the particular passivation promoter utilized, the metals level on the catalyst, the desired degree of passivation and the passivation zone and temperature.
  • the passivation promoter concentration may range between about 0.005 and about 0.20 weight percent of the catalyst present in the cracking system and preferably between about 0.025 and about 0.10 weight percent of the cracking catalyst present.
  • the reducing gas consumption rate in passivation zones 90,190, of Figures 1, 2, respectively will be a function, in part, of the metal contaminant levels on the catalyst, the desired degree of passivation and the amount of reducing gas infiltration into the regeneration zone, it is believed that the overall rate of consumption of the reducing gas will range from about 0.5 to about 260 SCF, preferably from about 1 to about 110 SCF, for each ton of catalyst passed through passivation zones 90,190 if hydrogen is used as the reducing gas.
  • Reaction zones 10, 110 and regeneration zones 26, 150 may be of conventional design and may be operated at conditions well-known to those skilled in the art.
  • Regeneration zones 26, 150 may be operated in either a net oxidizing or a net reducing mode.
  • oxidizing gas in excess of that required to completely combust the coke to C0 2 is added to the regeneration zone.
  • Regeneration zones 26 and 150 preferably should be operated in a net reducing mode, since carbon monoxide is a reducing gas which will help decrease the adverse catalytic properties of the metal contaminants on the catalyst prior to the catalyst entering passivation zones 90, 190.
  • the required residence time of the catalyst in the passivation zone may be dependent upon many factors, including the metal contaminant content of the catalyst, the degree of passivation required, the concentration of reducing gas in the passivation zone, and the passivation zone temperature.
  • the present invention is of particular utility where the passivation zone residence time is limited, such as where the passivation zone is disposed in the transfer zone communicating with the regeneration zone and reaction zone as shown in Figures 1 and 2. It is to be understood, however, that the present invention may be utilized where the passivation zone is not located in the transfer line.
  • the utility of the present invention may be seen from the following examples in which the effectiveness of cadmium-tin mixture, cadmium, germanium, indium, tellurium, and zinc is demonstrated, particularly when combined with the use of a passivation zone having a relatively short residence time.
  • GPF predicted (Individual effect of hydrogen passivation at each residence time)+(GFP for promoted sample with no hydrogen passivation).
  • the degree of passivation attributable to hydrogen passivation at each residence time is The degree of passivation attributable to the passivation promoter is where
  • the reduction in the gas producing factors is greater than the additive effect for the individual reductions in the gas producing factor for hydrogen passivation at a given passivation zone residence time and temperature and the effect of the metal passivation additive.
  • Tables I-VII demonstrate that the present invention is of particular utility in situations where the passivation zone residence time is relatively short, such as when a transfer line passivation zone is utilized.
  • Tables VIII and IX demonstrate that the unexpected reduction in the Gas Producing Factor may be affected by the passivation zone temperature.
  • a third sample of Super-DX metal contaminated cracking catalyst having 800 wppm NI and 2400 wppm V was placed in a passivation zone for varying times at 593°C and 649°C to determine the GPF at different passivation zone residence times.
  • GPF is the Gas Producing Factor obtained with no residence time in a passivation zone. Use of the term serves to minimize any inherent differences in contaminant metal activity of the catalyst samples, and permits comparison of the relative degrees of passivation as a function of cumulative hydrogen passivation residence time.
  • the present invention is of particular utility in situations where the passivation zone residence time is relatively short, such as where a transfer line passivation zone is utilized.
  • passivation promoters may be added to the cracking system or impregnated onto the cracking catalyst in elemental form or as a compound which may decompose to deposit the passivation promoter on the catalyst.
  • the particular passivation promoter which is utilized will be dependent on many factors, including availability, process economics, corrosion, and desired degree of passivation.
  • cadmium, germanium, indium, tellurium and zinc compounds are metal organic, organic or inorganic complex salts, with metal organic oil soluble compounds being particularly preferred.
  • the particular passivation promoter which is utilized will be dependent on many factors, including availability, process economics, corrosion, and desired degree of passivation.'Particularly preferred passivation promoters include cadmium-tin mixtures, cadmium, germanium, zinc and compounds thereof, with cadmium-tin mixtures and compounds thereof being especially preferred. When cadmium-tin mixtures are used, the cadmium-tin ratio, on an elemental metal basis, may change from about 0.1:1 to about 9:1.
  • the amount of passivation promoter which is utilized will be dependent on several factors, including the particular promoter utilized, the metal contaminant content on the catalyst, the desired degree of passivation, the average catalyst residence time in the passivation zone, and the conditions in the passivation zone.
  • the amount of passivation promoter which is used typically will range between about 0.005 and about 0.20 weight percent of the catalyst, preferably between about 0.025 and about 0.10 weight percent of the catalyst.
  • the method by which the passivation promoter is added to the catalyst is not believed to be critical.
  • the passivation promoter may be impregnated directly into the catalyst before use, or it may be added to the cracking system during operation.
  • a preferred method is to add the passivation promoter directly to the cracking system, preferably by adding a slip stream of the passivation promoter in a suitable carrier to the reaction zone.
  • catalyst residence time in the transfer zone typically is about 0.1 to about 2 minutes.
  • average catalyst residence time in transfer zone 190 typically ranges between about 0.1 and about 1.0 minutes.
  • the transfer zones of Figures 1 and 2 typically have sufficient residence time to passivate catalyst upon the introduction of reducing gas.
  • the reducing agent utilized in the passivation zone is not critical. It is believed that commercial grade CO and process gas streams containing H 2 and/or CO can be utilized. Hydrogen or a reducing gas stream comprising hydrogen is preferred, since this achieves the highest rate of metals passivation and the lowest level of metal contaminant potency.
  • Preferred reducing gas streams containing hydrogen include catalytic cracker tail gas streams, reformer tail gas streams, spent hydrogen streams from catalytic hydroprocessing, synthetic gas, steam cracker gas, flue gas, and mixtures thereof.
  • the reducing gas content in the passivation zone should be maintained between about 2% and about 100%, preferably between about 10% and about 75% of the total gas composition depending upon the hydrogen content of the reducing gas and the rate at which the reducing gas can be added without adversely affecting the catalyst circulation rate.
  • the stripping gas, if any, added through line 92 of Figure 1 and line 192 of Figure 2 will be a function in part of catalyst flow rate.
  • the stripping gas flow rates through each of these lines may range between about 0.1 SCF and about 80 SCF, preferably between about 8 and about 25 SCFM per ton of catalyst circulated.
  • Passivation zones 90, 190 may be constructed of any chemically resistant material capable of withstanding the relatively high temperature and the erosive conditions commonly associated with the circulation of cracking catalyst.
  • the materials of construction presently used for transfer piping in catalytic cracking systems should prove satisfactory.
  • the pressure in passivation zones 90, 190, of Figures 1, 2, respectively, will be substantially similar to or only slightly higher than the pressures in the regenerated catalyst transfer zones of existing catalytic cracking systems.
  • the pressure in passivation zone 90 may range from about 5 to about 100 psig, preferably from about 15 to about 50.
  • the pressure may range from about 15 psig to about 100 psig, preferably from about 20 psig to about 50 psig.
  • any commercial catalytic cracking catalyst designed for high thermal stability could be suitably employed in the present invention.
  • Such catalysts include those containing silica and/or alumina. Catalysts containing combustion promoters such as platinum also can be used. Other refractory metal oxides such as magnesia or zirconia may be employed and are limited only by their ability to be effectively regenerated under the selected conditions.
  • preferred catalysts include the combinations of silica and alumina, containing 10 to 50 wt.% alumina, and particularly their admixtures with molecular sieves or crystalline aluminosilicates.
  • Suitable molecular alumino-silicate materials such as faujasite, chabazite, X-type and Y-type aluminosilicate materials and ultra stable, large pore crystalline aluminosilicate materials.
  • the molecular sieve content of the fresh finished catalyst particles is suitable within the range from 5-35 wt.%, preferably 8-20 wt.%.
  • An equilibrium molecular sieve cracking catalyst may contain as little as about 1 wt.% crystalline material.
  • Admixtures of clay-extended aluminas may also be employed.
  • Such catalysts may be prepared by any suitable method such as by impregnation, milling, co-gelling, and the like, subject only to the provision that the finished catalyst be in a physical form capable of fluidization.

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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)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
  • Catalysts (AREA)

Claims (10)

1. Verfahren zur Passivierung eines zum Cracken von metallverunreinigten Kohlenwasserstoffeinsatzmaterialien zu Produkten mit niedrigerem Molekulargewicht in einer Crackanlage verwendeten Crackkatalysators, bei dem ein Kohlenwasserstoffeinsatzmaterial, welches eine aus der Gruppe Nickel, Vanadium, Eisen und deren Mischungen ausgewählte Metallverunreinigung enthält, in eine Reaktionszone der Crackanlage geleitet wird, welche darin einen Crackkatalysator zur Herstellung von gecrackten Produkten und mit abgescheidenem Koks und den Metallen verunreinigten Crackkatalysator enthält, der Koks aus dem Crackkatalysator in einer Regenierungszone entfernt wird, von welcher mindestens ein Teil des an Koks verarmten metallverunreinigten Crackkatalysators vor der Rückkehr des Katalysators in die Reaktionszone im Kreis durch eine unter Passivierungsbedingungen gehaltene Passivierungszone in die Reaktionszone geführt wird, wobei das Verfahren dadurch gekennzeichnet ist, daß eine wirksame Menge eines Passivierungsbeschleunigers in die Crackanlage gegeben wird, und der Passivierungsbeschleuniger aus der Gruppe der Metalle Cadmium-Zinn-Mischungen, Cadmium, Germanium, Indium, Tellur, Zink, deren Verbindungen und deren Mischungen ausgewählt ist.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Crackanlage außerdem eine mit der Regenierungszone und der Reaktionszone in Verbindung stehende Überführungszone aufweist und die Passivierungszone zumindest teilweise in der Überführungszone angeordnet ist.
3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß in die Passivierungszone ein reduzierendes Gas gegeben wird.
4. Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die Temperatur der Passivierungszone oberhalb etwa 700°C gehalten wird.
5. Verfahren nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die Temperatur in der Passivierungszone innerhalb des Bereiches von etwa 700 bis etwa 850°C gehalten wird.
6. Verfahren nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß die Konzentration des Passivierungsbeschleunigers in der Crackanlage zwischen etwa 0,005 und etwa 0,20 Gew.% des vorhandenden Crackkatalysators variiert.
7. Verfahren nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß die mittlere Verweildauer des Crackkatalysators in der Passivierungszone zwischen etwa 0,1 und etwa 20 Minuten variiert.
8. Verfahren nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, daß der Passivierungsbeschleuniger in die Reaktionszone gegeben wird.
9. Verfahren nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, daß der Katalysator vor seiner Einführung in die Crackanlage mit dem Passivierungsbeschleuniger imprägniert wird.
10. Verfahren nach einem der Ansprüche 1 bis 9, dadurch gekennzeichnet, daß das Verhältnis von Cadmium zu Zinn in der Mischung auf Basis der elementaren Metalle zwischen etwa 0,1:1 und etwa 9:1 variiert, wenn eine Cadmium-Zinn-Mischung als Passivierungsbeschleuniger verwendet wird.
EP19840308521 1983-12-09 1984-12-07 Passivation von Krackkatalysatoren Expired EP0147961B1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US06/559,918 US4504381A (en) 1983-12-09 1983-12-09 Passivation of cracking catalysts with cadmium and tin
US559918 1983-12-09
US06/559,891 US4522704A (en) 1983-12-09 1983-12-09 Passivation of cracking catalysts
US559891 2000-04-26

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EP0147961A2 EP0147961A2 (de) 1985-07-10
EP0147961A3 EP0147961A3 (en) 1986-12-30
EP0147961B1 true EP0147961B1 (de) 1989-04-05

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FR2653133A1 (fr) * 1989-10-13 1991-04-19 Total France Procede de conversion catalytique d'une charge d'hydrocarbures.
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US2901419A (en) * 1954-02-18 1959-08-25 Phillips Petroleum Co Catalytic conversion with the addition of a metal or metallic compound
DK160995C (da) * 1977-10-25 1991-11-04 Phillips Petroleum Co Forureningsdeaktiveret krakningskatalysator, dens anvendelse og middel til dens fremstilling
US4169042A (en) * 1978-03-13 1979-09-25 Phillips Petroleum Company Cracking process and catalyst for same containing tellurium
US4256564A (en) * 1979-04-03 1981-03-17 Phillips Petroleum Company Cracking process and catalyst for same containing indium to passivate contaminating metals
US4280898A (en) * 1979-11-05 1981-07-28 Standard Oil Company (Indiana) Fluid catalytic cracking of heavy petroleum fractions
US4280896A (en) * 1979-12-31 1981-07-28 Exxon Research & Engineering Co. Passivation of cracking catalysts
US4334979A (en) * 1980-04-11 1982-06-15 Phillips Petroleum Company Hydrocarbon cracking process using a catalyst containing germanium
AU7323481A (en) * 1981-03-19 1982-10-06 Ashland Oil, Inc. Immobilization of vanadia deposited on catalytic materials during carbo-metallic oil conversion

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EP0147961A2 (de) 1985-07-10
EP0147961A3 (en) 1986-12-30
CA1240946A (en) 1988-08-23

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