US2742518A - Naphtha from fluid coking of residua - Google Patents

Naphtha from fluid coking of residua Download PDF

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US2742518A
US2742518A US229205A US22920551A US2742518A US 2742518 A US2742518 A US 2742518A US 229205 A US229205 A US 229205A US 22920551 A US22920551 A US 22920551A US 2742518 A US2742518 A US 2742518A
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naphtha
coking
vessel
contact
solids
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William J Mattox
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ExxonMobil Technology and Engineering Co
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Exxon Research and Engineering Co
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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
    • C10G9/00—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
    • C10G9/28—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils with preheated moving solid material
    • C10G9/32—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils with preheated moving solid material according to the "fluidised-bed" technique
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
    • C10G2400/02—Gasoline

Definitions

  • this invention involvestreatment of the-olenic gasline fractionsprorducediin the fluid coking of residua in the vpresence ofjhydrogen transfercatalysts under hydrogen .transfer ⁇ canditions 'to ,effect partial hydrogenation of dioleiinic and/ or acetylenic compounds of the'cracled components.
  • coker reaction products mayy be combinedw'ith the coker naphtha and subjected tothe hydrogen transfer'treatment.
  • the treatment of the coker naphtha is effected at temperatures Vof about 10U-800 P., at pressures of from atmospheric to about'600 lbs. per sq.
  • catalysts such as .nickel sulfide, tungsten sulfide, molybdenum'sulde, preferably on a suitable support or one kor more of thechromitesof nickel, cobalt, zinc, copper, magnesium, tin or manganese or a chromia type catalyst such as chromium oxide on alumina 'or zinc aluminate spinel or there may also'be used a supported palladium or platinum composite containing about-0.01 to '2.0 wt. per cent of platinum lor palladium kupon a suitablek support lsuch as activated alumina, activated charcoal or the like.
  • catalysts such as .nickel sulfide, tungsten sulfide, molybdenum'sulde, preferably on a suitable support or one kor more of thechromitesof nickel, cobalt, zinc, copper, magnesium, tin or manganese or a chromia type catalyst such as chromium
  • In-the drawing l0 is a coking vessel similar to conventional dense bed, 'bottom -drawoif lluidized solids contacting-vessels and 'l1-is a transferline'for the introduction of finely/divided solids in admixture with fluidizing gas or vapors.
  • the transfer Vline discharges into an inlet chamber 12 inthe bottom of coking'vessel '10.
  • the inlet chamber i2 comprises van -inverted conical section superposed ⁇ by a horizontally ⁇ disposed perforatedplate or .grid member L13 whichserves to distribute the incoming solids and -vapors uniformly over theentire-cross section ofthe coking vessel 10.
  • the colting-vessel is 'charged with finely divided, substantially inertlsolids such as sand, pumice, petroleum coke, clay, etc., havingaparticlesize of about 30-400f mesh which are .maintained :as ia dense, -fluidized,
  • turbulentbed 14 having Va definite @level ..15 or interfaceV separating the turbulent bed or dense phase 14 from an upper dilute*orffdisperse'phase .16.
  • Y Linear superiicialrgas velocities through'the cokingxvessel 10. may be varied b etween about 013 tofabout 5.0 ft.-per second toestablish apparent densities ofabout20'to .6,0 lbs. per cu. ft. in dense bed y:154 andfabout 0.00l'to 0 1 lb. per cu. -ft.,in disperse 1 phase 1-6.
  • a line 17 -isprovi'dedthrcugh .which'residua for coking is supplied-to thecoking vessel" 10.
  • the line 1.7 connects to lsuitable fspray nozzles #mounted on manifoldl or ⁇ header 1S arranged inthe upper rparts of the' coking vessel 1i).
  • The-distance of travel of droplets of residuurn through the 'disperse phase, i. e., before lcontact with the main body ofuidized solids or dense bed "14 should be about 5 Ito 20 ifeet,prefer-ablyabout 10-feet.
  • Design of the coking vessel and thefuidizing conditions therein should be suchlas lu'lill'perrnit a residencetirne of theiupflowing vapors Ain-the fdense bed 14 ⁇ of about' 3to 60seconds and descending ktimefor liquid lresiduum droplets through the disperse ,phase 16 of ⁇ aboutgOzS ⁇ to 10 Aseconds depending u ponthe degree 'of dispersion ofthesprayiandthe velocity of upllowing gases.
  • the liquid -re ⁇ siduum ifeed -rate Patented Apr. 17, 195eV may be about 0.15 to 3.0 wt./hr./wt. (lbs. of residuum per hour per lb. of solid contact material in the coking vessel).
  • the temperature within the dense bed 14 should be maintained at about 1050-1 150 F. by circulation of the contact solids as will now be described.
  • the stripped contact solids are discharged from conduit 20 through control valve 23 into transfer line 24 where they are picked up by a stream of air or combustion gas and conveyed to heater vessel Z5.
  • the transfer line 24 discharges the suspension of contact solids in air or combustion gas into inlet chamber 26 arranged adjacent the bottom of heater vessel 25.
  • the inlet chamber 26, similarly to the inlet chamber 12 in coking vessel 10, comprises an inverted conical section superposed by a horizontally disposed perforated plate or grid 27 which serves to distribute the incoming solids and air uniformly over the entire cross section of the heater vessel 25.
  • the linear superficial velocity of the air or combustion gas passing through the heater vessel 2S, similarly to the gas velocities through coking vessel 10, may be varied between about 0.3 to about 5.() ft.
  • the combustion gases are withdrawn overhead from the heater through a cyclone separator 31 or the like which serves to separate most of the entrained solid particles which may be returned to the dense bed 28 via the dip leg attached to the bottom of separator 3i..
  • the combustion gases pass to the atmosphere via stack 32 or; if desired, to heat recovery equipment and thence to the atmosphere or to storage for use as stripping gas or the like.
  • the solid material withdrawn from the coking vessel 10 and supplied to heater vessel 25 will be essentially 100% colte.
  • a material such as sand is used as the contact material it is advisable to maintain the coke content at a relatively high level, for example about 5 to 20 wt. percent at all times in order to maintain good burning rates and to achieve good utilization of the air supplied to the heater vessel 25.
  • the solids leaving the coking vessel 10 will ordinarily have a coke content that is about 0.5 to about l0 wt. percent higher than that of the solids leaving the heater vessel. This figure depends upon the amount of coke deposited by the particular feed used and the ratio of solids circulation rate to oil feed rate.
  • Fluidized solid contact material carrying about 5 to ltl wt. percent of colte may be withdrawn from the coiting vessel for circulation to the heater vessel at a rate of about i to l0 times the total oil feed rate to the coking vessel.
  • "ihc suspension of withdrawn contact material in air or combustion gas passes through the transfer line 2d :md distributor plate 27 to lortu a dense iluidized bed 2S in which the desired amount of coke is burned oi of the contact particles.
  • the solid contact materials are heated to temperatures of about 1150" to l300 F.
  • the temperature of the dense bed of contact material in heater vessel 25 should be at least about 50 higher than the temperature of the denseizidized bed 14 in colting vessel 1t).
  • About G-6000 cu. ft. of air per bbl. of total feed to the colting vessel will sufice to burn ofi all the coke formed and maintain the system in heat balance at the conditions speciiied.
  • Fluidized solid contact material at the temperature of the dense bed 28 is Withdrawn through the standpipe 33 connected to the bottom of heater vessel 2S.
  • the solid contact materials are aerated and/or stripped with steam or inert gas supplied through one or more taps 34 provided on the standpipe 33.
  • the reheated contact solids are discharged from standpipe 33 through control valve 35 into transfer line 11 where they are picked up by a stream of fiuidized gas and conveyed to coking vessel 10 at substantially the same rate at which the solid particles were withdrawn therefrom so as to supply the heat required in coking vessel 10 as sensible heat of the reheated contact solids.
  • the uidizing gas used to convey the solid contact particles through transfer line 11 may be steam or an inert gas but is preferably a naphtha cut since the naphtha is not only improved or upgraded by the treatment in the coking vessel 10 but more importantly it appears to exert a synergistic etfect on the conversion of the residuum in the coking operation to form larger amounts of valuable liquid products.
  • the naphtha feed stock which may be a virgin naphtha, a catalytically cracked naptha, a Fischer- Tropsch naphtha or the like having a boiling range of between bout and 430 F.
  • inlet 37 is supplied through inlet 37 and may, if desired, be passed through heater coils 38 disposed in the dense bed 28 in order to preheat the same prior to its passage via line 39 into transfer line 11 Where it is mixed with the reheated solid contact particles or it may be supplied in liquid form to transfer line 11 by means of inlet line 40.
  • a further possibility is to utilize naphtha, preheated or not as desired, as the uidizing medium and to supplement its action by the introduction of a second iluidizing medium such as steam through inlet line 40.
  • a second iluidizing medium such as steam through inlet line 40.
  • the feed rate of the naphtha to line 37 is maintained at a rate of about 0.25 to about 4.0 wt./hr./wt. (lbs. of naphtha per hour per lb. of contact solid in the coking vessel).
  • Vaporous coldng products containing small amounts of entrained solid particles pass into the disperse phase 16 in the upper part of coker vessel 10 and pass therethrough countercurrently to descending droplets of residuum feed.
  • the said residuum feed droplets are preheated and pretreated to give olf relatively low temperature coking products during their passage through the dilute or disperse phase.
  • the Vaporous coking products are quenched to temperatures approximating or somewhat above the temperature of the residuum feed thereby avoiding excessive cracking.
  • most of the solid particles entrained with the Vaporous coking products become caught by the descending liquid droplets and are thereby scrubbed out of the reaction products so that no special solids separation equipment is required.
  • Vaporous coking products amount to about 90-95 wt. percent on total feed and pass overhead from coking vessel 10 through line 42 at temperatures of about 700- 1000 F. into fractionating column 43.
  • About 20-30 wt. percent of product gases based on total feed are taken overhead from fractionator 43 through line 44 for use in accordance with the present invention as will presently be described.
  • part of the cracked gases may be withdrawn from the unit and passed to suitable processing or recovery equipment.
  • Coker bottomsk boiling above about 950 F. and ⁇ -amounting uto ⁇ about .1Q-.10 voLpercent of the .total feed is Awithdrawn'through 1ine47 .and passed to ful .oil storage or lblending or, .if ⁇ desired, .the bottoms .fraction may tbe .recycled to Athe coking vessel for .retreatment therein.
  • the cracked gaseous product and the naphtha cut removed through line 45 are combined and subjected to a treatment to convert the diolenic and/ or acetylenic components to monoolenic compounds, or what is equivalent thereto, passing a C2-, Ca-, or Ct to 430 F. or lower end point naphtha or gasoline fraction over hydrogenation type catalysts which are active for hydrogenation of dioleflns to monooleins but which are relatively inactive for lthe hydrogenation of monoolens to paraliins.
  • the naphtha or gasoline fraction is somewhat delicient in naphthenic hydrocarbons, i. e., contains less than about 5-15 Vol. percent of naphthenes it may be desirable to add a virgin or other naphtha stock to supply naphthenes for hydrogen exchange.
  • the naphtha removed through line 4S and the cracked gases taken overhead through line 44 are combined in conduit 48 after the addition, if desired or necessary, of a naphthenic naphtha supplied through line 49.
  • the resultant mixture is then subjected to hydrogen transfer conditions to effect simultaneous reforming and stabilization.
  • Suitable catalysts that may be used to effect the selective conversion of the diolelinic and acetylenic components to monooleiins include nickel sulfide, tungsten sulfide, molybdenum sulfide or mixtures of these preferably upon a support such as alumina, silica, zirconia, titania, etc. lnstead of said sullides there may be used one lor more of the chromites of nickel, cobalt, Zinc, copper, magnesium, tin or manganese. Chromia type catalysts such as chromia on 'alumina or upon zinc aluminate spine] may also be used. Supported palladium or platinum composites containing about 0.01 to 2.0 wt.
  • platinum or palladium upon a suitable support such as silica get, activated alumina or activated carbon may be used.
  • a suitable support such as silica get, activated alumina or activated carbon
  • oxygencontaining materials such as H2O, CO, etc. which act as mild poisons and inhibit the hydrogenation of mono-olelins to parafins.
  • Contact of the naphtha and the oleflnic cracked gases with the above catalytic agents may be eiected in any desired manner, for example with finely divided catalyst particles in a fluidized solids reactor system of the upflow or bottom drawoff type or in a fixed or moving bed or in a suspensoid type operation.
  • Contact of the naphthacracked gas mixture with the catalyst may be effected at temperatures of Afrom about 100 .to about 800 F. at pressures"fromatmospheric 'to about ⁇ 60"0lbs. per sq. inch gauge.
  • the feed rate should Abe within the range of about '0.1 Tto .aboutfO v./v.”/hr.
  • the ⁇ .preferred 'temperature range will be "influenced by catalyst type since the "above-described 'catalysts'will .not always :be equivalent.
  • the lnickel 'sulfide preparations require utemperatures 'of about 30G-1500".
  • copper chromite about l100-"650 ii., 'and 'chromia-'containing cornposites about 50G-"800' E 'Platinum or palladiumecontaining composites can be used at temperatures of V"from about 100-"750 F.
  • the mixture of naphtha and cracked gases "is passed xthrough ⁇ 'conduit 48.
  • ⁇ rCatalyst of the Y'abeve-'mentioned classes isdischarged from hopper 49 into conduit4'8 in *t'hedesired amount.
  • reaction 'mixture 'discharged from heater ⁇ 4coils -50 i may thenbe passed through cyclone separatorsror thelike to free 'the hydrocarbon zmaterials of Athe accompanying catalyst particles.
  • a separate treating vessel could be v'used charged with aiixed :bed of catalyst particles and the mixture of naphtha and cracked ygases merely pas-sed through lsuitable Ipreheat'er eoils-arranged in the -heater vessel 25 or in a separate furnace and -thence through lthe fixed catalyst bed to suitable fractionating equipment.
  • the above C4 cut plus C5-430" F. gasoline with about 25 vol. per cent of a naphthenic straight-run gasoline fraction is contacted with a 10% copper chromite-silica catalyst at 600 F. and atmospheric pressure to give without substantial volumetric losses a stable motor fuel of 90432 unleaded research octane number and having less than 1% of dioleins.
  • the C4 cut low is butadiene but high in total unsaturation (91%) is suitablefor alkylation, polymerization, etc.
  • a method which comprises coking a lpetroleum residuum stock in a uidized bed of substantially inert contact material attemperatures of l000-1200 F.
  • Y subjecting a mixture of the reaction products from said coking process boiling below about 430 F., and a naphtha stock rich in naphthenes to treatment in contact with a chromite hydrogenation catalyst etective for the conversion of dioleiinic and acetylenic compounds to monooleiins but which is relatively inactive for the hydrogenation of monoolefins to paratlins thereby selectively converting the dioleiinic and acetylenic components to monoolelins.
  • a method which comprises coking a petroleum residuum stock in -a uidized bed of substantially inert contact material in the presence of substantial amounts of added naphtha at temperatures of 1000-1200 F. and subjecting a mixture of the reaction products from said coking process boiling below about 430 F., and a naphtha stock rich in naphthenes to treatment in contact with a chromite hydrogenation catalyst effective for the conversion of diolenic and acetylenic compounds to monoolefins but which is relatively inactive for the hydrogenation of monoolens to parains thereby selectively converting the diolenic and acetylenic components to monoolens.
  • a method which comprises coking a petroleum residuum stock in a uidized bed of substantially inert contact material at temperatures of 100G-1200 F. and subjecting a mixture of the reaction products from said coking process boiling below about 430 F., and a naphtha stock rich in naphthenes to treatment in contact with a chromite hydrogenation catalyst eiective for the conversion of diolefinic and acetylenic compounds to monoolens but which is relatively inactive for the hydrogenation of monoolens to parafns, at temperatures of from 100 to 800 F., pressures of from atmospheric to 600 lbs/sq. in. and at feed rates of from 0.1 to 5.0 v./v./hr. thereby selectively converting the diolenic and acetylenic components to monoolens.
  • a method which comprises coking a petroleum residuum stock in, a tluidized bed of substantially inert contact material in the presence of substantial amounts of added naphtha at temperatures of 1000-1200 F. and subjecting a mixture of the reaction products from said coking process boiling below about 430 F., and a naphtha stock rich in naphthenes to treatment in contact with a chromite hydrogenation catalyst eiective for the conversion of diolenic and acetylenic compounds to monoolens but which is relatively inactive for the hydrogenation of monoolens to parains, at temperatures of from 100 to 800 F., pressures of from atmospheric to 600 1bs./sq. in. and at feed rates of from 0.1 to 5.0 v./v./hr, thereby selectively converting the diolenic and acetylenic components to monoolens.

Description

April 17, 1956 w. J. MATTox NAPHTHA FROM FLUID coxING oF RESIDUA Filed May 3l. 195] United States Patent O The present inventionpperta'ins to nanphtha improvement and more particularly to thecatalytic 4reforniing of Yhydrocarbon fractions .boiling within the motor fuel or naphtha boiling range prepared by the fluid coking of .residua to convert said hydrocarbon fractions ,into motor fuels .of improved stability and cleanliness and lof good antiknock qualit-y. -Speciiically this invention'involvestreatment of the-olenic gasline fractionsprorducediin the fluid coking of residua in the vpresence ofjhydrogen transfercatalysts under hydrogen .transfer `canditions 'to ,effect partial hydrogenation of dioleiinic and/ or acetylenic compounds of the'cracled components. y v
Numereusproesses 'have beenrrenosed for the C011- versvn er reforming of hydrocarbon fractions 'boiling within the -rnotor .fuel or naphtha ,range .t increase the arometipity .anlimprove zthe antiknvsk '-.ehetacteristics of Asaid"hydrocarlmnfractions. Reforming processes emv plenas catalysts, espeially ilyroiorfmns and aromatizmaarewiteiy usein the petrleum instrytoupsrade or hnprovetheanti-"knock characteristics of motor 'fuels It "has "also '"beenproposedto subject 'naphdreriicpetroleum fractionsto hydrogen -transfer with'normally'liquid olen'ic @hydrocarbons whereby 'the 4rnaphthenic constituents are converted tol aromatics and fthe` leinic hydrocarbons areconverted to vvparaflnic zhydrocarbonsby `theihydrogen removedfrom `the naphtlrenicconstituents. A 1
' in viewoff -thegincreasing=dernarfds for greater lvolumes of motor l'fuel {of} improved'fan'tiknolpropertiesberesidum conversion processes 4#and catalytic reforming processes have been thesubjectof intensive investigation E'in Janfeff ort to ilind new catalysts ornewy conditions orft'echques for A'increasing fthe total Vaniuun't Lof motor fuel .produced grading -of nnotor "lfuelmr =naphtha fractions :to increase yields vanti/'or improve une istability, cleanliness "and anti-l knoek characteristics of :the motor `.fuel.p1'oduct.
lt isthe fobiectrof this inventionitorprovideianiimproved` process fforvpreparing :motors-fuels thighyields, tof ,good stability; cleanliness and :anti-knock :properties 'itis falso @the :object .of ;tliis .finventionptozprepare motor fuelszinrh'igh yields-.andiwithigoodcstabilityeandr anti-knock properties by a v;combined ;.proce'ss iof .coking residua-5in admixtuie iwithfnaphtha rbythe fluidi` coking :technique .fand
treating the resultant inaphtha under :hydrogen @transfer l seduced by .was .residual seeks Qn eid, 'sae-f lyticallyinert solids such as sanihfpet'roleum cmrlenpuniice' ICC 12' or the like .at-.temperatures yabove l000 F., preferably between 1050 and `1.150" P. .in the presenceof substantial proportions, atleast 25% andpreferably about 50-75 vol. percent'on tot-al 'hydrocarbon Jfeed of va naphtha boiling within Ithe range .of about '1Z0-43,0 F. are. subjected to hydrogen transfer `conditions adequate to Velfect partial hydrogenation .ofdioleiinc fand/ or `acetylenic .compounds of the cracked components. By suitable control tof .the feedstock and cracking .or eoking 4Condit-ions it may be possible toiprovide suicient naphthenic clovmpoundsin the `coker reaction products tofobviate vthe necessity of adding an extraneous ,stream v of naphtha to the .c oker naphtha to facilitate hydrogen transfer. 'If the Cokerv naphtha is deficient in naphthenic components however, it is advisable to add virgin naphthafcontaining substantialamounts-of naphthenichydrocabons. If desired, one
or ymoreof the'Cz, 'C3 and'Ci fractions of coker reaction products mayy be combinedw'ith the coker naphtha and subjected tothe hydrogen transfer'treatment. The treatment of the coker naphtha is effected at temperatures Vof about 10U-800 P., at pressures of from atmospheric to about'600 lbs. per sq. inch and in contact with catalysts such as .nickel sulfide, tungsten sulfide, molybdenum'sulde, preferably on a suitable support or one kor more of thechromitesof nickel, cobalt, zinc, copper, magnesium, tin or manganese or a chromia type catalystsuch as chromium oxide on alumina 'or zinc aluminate spinel or there may also'be used a supported palladium or platinum composite containing about-0.01 to '2.0 wt. per cent of platinum lor palladium kupon a suitablek support lsuch as activated alumina, activated charcoal or the like.
Reference is made-to the accompanying-drawing illustrating diagrammatically'one embodiment of lthe present invention.
In-the drawing l0 is a coking vessel similar to conventional dense bed, 'bottom -drawoif lluidized solids contacting-vessels and 'l1-is a transferline'for the introduction of finely/divided solids in admixture with fluidizing gas or vapors. The transfer Vline discharges into an inlet chamber 12 inthe bottom of coking'vessel '10. The inlet chamber i2 comprises van -inverted conical section superposed `by a horizontally `disposed perforatedplate or .grid member L13 whichserves to distribute the incoming solids and -vapors uniformly over theentire-cross section ofthe coking vessel 10. The colting-vessel is 'charged with finely divided, substantially inertlsolids such as sand, pumice, petroleum coke, clay, etc., havingaparticlesize of about 30-400f mesh which are .maintained :as ia dense, -fluidized,
turbulentbed 14 having Va definite @level ..15 or interfaceV separating the turbulent bed or dense phase 14 from an upper dilute*orffdisperse'phase .16. Y Linear superiicialrgas velocities through'the cokingxvessel 10.may be varied b etween about 013 tofabout 5.0 ft.-per second toestablish apparent densities ofabout20'to .6,0 lbs. per cu. ft. in dense bed y:154 andfabout 0.00l'to 0 1 lb. per cu. -ft.,in disperse 1 phase 1-6.
A line 17 -isprovi'dedthrcugh .which'residua for coking is supplied-to thecoking vessel"=10. The line 1.7 connects to lsuitable fspray nozzles #mounted on manifoldl or` header 1S arranged inthe upper rparts of the' coking vessel 1i). The-distance of travel of droplets of residuurn through the 'disperse phase, i. e., before lcontact with the main body ofuidized solids or dense bed "14 should be about 5 Ito 20 ifeet,prefer-ablyabout 10-feet. Design of the coking vessel and thefuidizing conditions therein should be suchlas lu'lill'perrnit a residencetirne of theiupflowing vapors Ain-the fdense bed 14`of about' 3to 60seconds and descending ktimefor liquid lresiduum droplets through the disperse ,phase 16 of `aboutgOzS `to 10 Aseconds depending u ponthe degree 'of dispersion ofthesprayiandthe velocity of upllowing gases. The liquid -re`siduum ifeed -rate Patented Apr. 17, 195eV may be about 0.15 to 3.0 wt./hr./wt. (lbs. of residuum per hour per lb. of solid contact material in the coking vessel). The temperature within the dense bed 14 should be maintained at about 1050-1 150 F. by circulation of the contact solids as will now be described.
Contact solids from the dense bed 14 pass downwardly around inlet chamber 12 at the bottom of the coking vessel l to an outlet pipe 20. Stripping gas such as steam may be introduced at i9 to remove entrained Vaporous material from the Contact solids passing to the outlet pipe. Part of thc contact solids passing into outlet pipe may be withdrawn from the system through valve controlled discharge line 21 in order to maintain contact solids inventory at the desired level. The remainder of the contact solids pass down through conduit 20, preferably countercurrent to a stream of steam or other inert stripping or tluidizing gas supplied through one or more taps 22 which serves to maintain the solid particles in iiuidized condition and remove additional vaporizable materials from the Contact solids before admixture of said solids with air or combustion gas.
The stripped contact solids are discharged from conduit 20 through control valve 23 into transfer line 24 where they are picked up by a stream of air or combustion gas and conveyed to heater vessel Z5. The transfer line 24 discharges the suspension of contact solids in air or combustion gas into inlet chamber 26 arranged adjacent the bottom of heater vessel 25. The inlet chamber 26, similarly to the inlet chamber 12 in coking vessel 10, comprises an inverted conical section superposed by a horizontally disposed perforated plate or grid 27 which serves to distribute the incoming solids and air uniformly over the entire cross section of the heater vessel 25. The linear superficial velocity of the air or combustion gas passing through the heater vessel 2S, similarly to the gas velocities through coking vessel 10, may be varied between about 0.3 to about 5.() ft. per second and forms therein a dense, iluidized, turbulent bed 2S of contact solids having a definite level 29 or interface separating the dense bed from a dilute or disperse phase 36 in the upper part of the heater vessel 25. The combustion gases are withdrawn overhead from the heater through a cyclone separator 31 or the like which serves to separate most of the entrained solid particles which may be returned to the dense bed 28 via the dip leg attached to the bottom of separator 3i.. The combustion gases pass to the atmosphere via stack 32 or; if desired, to heat recovery equipment and thence to the atmosphere or to storage for use as stripping gas or the like.
in the event that petroleum colte is used as the contact solid, the solid material withdrawn from the coking vessel 10 and supplied to heater vessel 25 will be essentially 100% colte. ln case a material such as sand is used as the contact material it is advisable to maintain the coke content at a relatively high level, for example about 5 to 20 wt. percent at all times in order to maintain good burning rates and to achieve good utilization of the air supplied to the heater vessel 25. The solids leaving the coking vessel 10 will ordinarily have a coke content that is about 0.5 to about l0 wt. percent higher than that of the solids leaving the heater vessel. This figure depends upon the amount of coke deposited by the particular feed used and the ratio of solids circulation rate to oil feed rate. Fluidized solid contact material carrying about 5 to ltl wt. percent of colte may be withdrawn from the coiting vessel for circulation to the heater vessel at a rate of about i to l0 times the total oil feed rate to the coking vessel. "ihc suspension of withdrawn contact material in air or combustion gas passes through the transfer line 2d :md distributor plate 27 to lortu a dense iluidized bed 2S in which the desired amount of coke is burned oi of the contact particles. As a result of the combustion of the coke, taking place in the transfer line and heater vessel 25, the solid contact materials are heated to temperatures of about 1150" to l300 F. Ordinarily the temperature of the dense bed of contact material in heater vessel 25 should be at least about 50 higher than the temperature of the dense luidized bed 14 in colting vessel 1t). About G-6000 cu. ft. of air per bbl. of total feed to the colting vessel will sufice to burn ofi all the coke formed and maintain the system in heat balance at the conditions speciiied.
Fluidized solid contact material at the temperature of the dense bed 28 is Withdrawn through the standpipe 33 connected to the bottom of heater vessel 2S. The solid contact materials are aerated and/or stripped with steam or inert gas supplied through one or more taps 34 provided on the standpipe 33. The reheated contact solids are discharged from standpipe 33 through control valve 35 into transfer line 11 where they are picked up by a stream of fiuidized gas and conveyed to coking vessel 10 at substantially the same rate at which the solid particles were withdrawn therefrom so as to supply the heat required in coking vessel 10 as sensible heat of the reheated contact solids.
The uidizing gas used to convey the solid contact particles through transfer line 11 may be steam or an inert gas but is preferably a naphtha cut since the naphtha is not only improved or upgraded by the treatment in the coking vessel 10 but more importantly it appears to exert a synergistic etfect on the conversion of the residuum in the coking operation to form larger amounts of valuable liquid products. The naphtha feed stock, which may be a virgin naphtha, a catalytically cracked naptha, a Fischer- Tropsch naphtha or the like having a boiling range of between bout and 430 F. is supplied through inlet 37 and may, if desired, be passed through heater coils 38 disposed in the dense bed 28 in order to preheat the same prior to its passage via line 39 into transfer line 11 Where it is mixed with the reheated solid contact particles or it may be supplied in liquid form to transfer line 11 by means of inlet line 40. A further possibility is to utilize naphtha, preheated or not as desired, as the uidizing medium and to supplement its action by the introduction of a second iluidizing medium such as steam through inlet line 40. Upon contacting the reheated contact solids the naphtha is vaporized and/or partially cracked to form a limited amount of normally gaseous hydrocarbons. The feed rate of the naphtha to line 37 is maintained at a rate of about 0.25 to about 4.0 wt./hr./wt. (lbs. of naphtha per hour per lb. of contact solid in the coking vessel).
Vaporous coldng products containing small amounts of entrained solid particles pass into the disperse phase 16 in the upper part of coker vessel 10 and pass therethrough countercurrently to descending droplets of residuum feed. In this way the said residuum feed droplets are preheated and pretreated to give olf relatively low temperature coking products during their passage through the dilute or disperse phase. Simultaneously the Vaporous coking products are quenched to temperatures approximating or somewhat above the temperature of the residuum feed thereby avoiding excessive cracking. At the same time most of the solid particles entrained with the Vaporous coking products become caught by the descending liquid droplets and are thereby scrubbed out of the reaction products so that no special solids separation equipment is required.
The Vaporous coking products amount to about 90-95 wt. percent on total feed and pass overhead from coking vessel 10 through line 42 at temperatures of about 700- 1000 F. into fractionating column 43. About 20-30 wt. percent of product gases based on total feed are taken overhead from fractionator 43 through line 44 for use in accordance with the present invention as will presently be described. In the event that there are excessive amounts of cracked gases available, part of the cracked gases may be withdrawn from the unit and passed to suitable processing or recovery equipment.
blended with virgingas oilandpassed to .a-.ca'ta1yt'ic crack`Y ingoperation. Coker bottomsk boiling above about 950 F. and `-amounting uto `about .1Q-.10 voLpercent of the .total feed is Awithdrawn'through 1ine47 .and passed to ful .oil storage or lblending or, .if\desired, .the bottoms .fraction may tbe .recycled to Athe coking vessel for .retreatment therein. K
The foregoing operations are essentially the same as set out in application SerialNo. 182,036, .tiled August 29, 1950, by Charles.N..Kimber1in.etal., now U. S. Patent No. 2,636,844. j
It-has been found-that the-lowerboiling hydrocarbons produced inthe cokingof residua as described above contain l'dioleins such -as butadiene, fpent'a'diene as Well `as higher boiling diolefns --and -while theymay be present in various fractions -in 4appreciable quantities the amounts present 'are =notsuflicient-to-justify theirseparation. Such materials, however, `are-notdesirable components `of i'feeds to operations-*involving polymerization, falkylation, etc., and the higher boiling liquid diolelins are notoriously bad gum formers in naphthas or motor fuels. In accordance with this invention the cracked gaseous product and the naphtha cut removed through line 45 are combined and subjected to a treatment to convert the diolenic and/ or acetylenic components to monoolenic compounds, or what is equivalent thereto, passing a C2-, Ca-, or Ct to 430 F. or lower end point naphtha or gasoline fraction over hydrogenation type catalysts which are active for hydrogenation of dioleflns to monooleins but which are relatively inactive for lthe hydrogenation of monoolens to paraliins. If the naphtha or gasoline fraction is somewhat delicient in naphthenic hydrocarbons, i. e., contains less than about 5-15 Vol. percent of naphthenes it may be desirable to add a virgin or other naphtha stock to supply naphthenes for hydrogen exchange.
To effect the desired after treatment of the naphtha, the naphtha removed through line 4S and the cracked gases taken overhead through line 44 are combined in conduit 48 after the addition, if desired or necessary, of a naphthenic naphtha supplied through line 49. The resultant mixture is then subjected to hydrogen transfer conditions to effect simultaneous reforming and stabilization.
Suitable catalysts that may be used to effect the selective conversion of the diolelinic and acetylenic components to monooleiins include nickel sulfide, tungsten sulfide, molybdenum sulfide or mixtures of these preferably upon a support such as alumina, silica, zirconia, titania, etc. lnstead of said sullides there may be used one lor more of the chromites of nickel, cobalt, Zinc, copper, magnesium, tin or manganese. Chromia type catalysts such as chromia on 'alumina or upon zinc aluminate spine] may also be used. Supported palladium or platinum composites containing about 0.01 to 2.0 wt. percent of platinum or palladium upon a suitable support such as silica get, activated alumina or activated carbon may be used. In this case it is desirable to add small amounts of oxygencontaining materials such as H2O, CO, etc. which act as mild poisons and inhibit the hydrogenation of mono-olelins to parafins.
Contact of the naphtha and the oleflnic cracked gases with the above catalytic agents may be eiected in any desired manner, for example with finely divided catalyst particles in a fluidized solids reactor system of the upflow or bottom drawoff type or in a fixed or moving bed or in a suspensoid type operation. Contact of the naphthacracked gas mixture with the catalyst may be effected at temperatures of Afrom about 100 .to about 800 F. at pressures"fromatmospheric 'to about `60"0lbs. per sq. inch gauge. The feed rate should Abe within the range of about '0.1 Tto .aboutfO v./v."/hr. -"`('lquid 'volumes .of r'oil per volume V o'lcatalyst penhour). The `.preferred 'temperature range will be "influenced by catalyst type since the "above-described 'catalysts'will .not always :be equivalent. For example, the lnickel 'sulfide preparations require utemperatures 'of about 30G-1500". VAF., copper chromite about l100-"650 ii., 'and 'chromia-'containing cornposites about 50G-"800' E 'Platinum or palladiumecontaining composites can be used at temperatures of V"from about 100-"750 F.
As shown in the drawing, the mixture of naphtha and cracked gases "is passed xthrough `'conduit 48. `rCatalyst of the Y'abeve-'mentioned classes isdischarged from hopper 49 into conduit4'8 in *t'hedesired amount. The'mixture of catalyst and oil is then'passed Jvia lline y48=through"lreater coils l"50 which l'may'advantageonsly'be Jarranged in the dense ibedZS within vheater 4ve'sse'l 25. The reaction 'mixture 'discharged from heater `4coils -50 i may thenbe passed through cyclone separatorsror thelike to free 'the hydrocarbon zmaterials of Athe accompanying catalyst particles. Alternatively a separate treating vessel could be v'used charged with aiixed :bed of catalyst particles and the mixture of naphtha and cracked ygases merely pas-sed through lsuitable Ipreheat'er eoils-arranged in the -heater vessel 25 or in a separate furnace and -thence through lthe fixed catalyst bed to suitable fractionating equipment.
The following example is illustrative of the present invention:
Example Employing a 2.4% So. La. residuum (11.9 API gravity) a coking operation was'carried out in a luidized bed of 100-200 mesh sand at an average bed temperature of 1080 F., 1.6 w./hr./w., 14 p. s. i. g., and with 40 wt. per cent steam diluent. The coke produced amounted to 10 wt. per cent of the residuum feed and the approxi-l mately 90% of gaseous and liquid products was distributed as follows:
The above C4 cut plus C5-430" F. gasoline with about 25 vol. per cent of a naphthenic straight-run gasoline fraction is contacted with a 10% copper chromite-silica catalyst at 600 F. and atmospheric pressure to give without substantial volumetric losses a stable motor fuel of 90432 unleaded research octane number and having less than 1% of dioleins. The C4 cut low is butadiene but high in total unsaturation (91%) is suitablefor alkylation, polymerization, etc.
The foregoing description contains a limited number of embodiments of the present invention. It will be understood, however, that numerous variations areY possible without departing from the scope of the following claims.
What is claimed is:
l. A method which comprises coking a lpetroleum residuum stock in a uidized bed of substantially inert contact material attemperatures of l000-1200 F. and
Y subjecting a mixture of the reaction products from said coking process boiling below about 430 F., and a naphtha stock rich in naphthenes to treatment in contact with a chromite hydrogenation catalyst etective for the conversion of dioleiinic and acetylenic compounds to monooleiins but which is relatively inactive for the hydrogenation of monoolefins to paratlins thereby selectively converting the dioleiinic and acetylenic components to monoolelins.
2. A method which comprises coking a petroleum residuum stock in -a uidized bed of substantially inert contact material in the presence of substantial amounts of added naphtha at temperatures of 1000-1200 F. and subjecting a mixture of the reaction products from said coking process boiling below about 430 F., and a naphtha stock rich in naphthenes to treatment in contact with a chromite hydrogenation catalyst effective for the conversion of diolenic and acetylenic compounds to monoolefins but which is relatively inactive for the hydrogenation of monoolens to parains thereby selectively converting the diolenic and acetylenic components to monoolens.
3. A method which comprises coking a petroleum residuum stock in a uidized bed of substantially inert contact material at temperatures of 100G-1200 F. and subjecting a mixture of the reaction products from said coking process boiling below about 430 F., and a naphtha stock rich in naphthenes to treatment in contact with a chromite hydrogenation catalyst eiective for the conversion of diolefinic and acetylenic compounds to monoolens but which is relatively inactive for the hydrogenation of monoolens to parafns, at temperatures of from 100 to 800 F., pressures of from atmospheric to 600 lbs/sq. in. and at feed rates of from 0.1 to 5.0 v./v./hr. thereby selectively converting the diolenic and acetylenic components to monoolens.
4. A method which comprises coking a petroleum residuum stock in, a tluidized bed of substantially inert contact material in the presence of substantial amounts of added naphtha at temperatures of 1000-1200 F. and subjecting a mixture of the reaction products from said coking process boiling below about 430 F., and a naphtha stock rich in naphthenes to treatment in contact with a chromite hydrogenation catalyst eiective for the conversion of diolenic and acetylenic compounds to monoolens but which is relatively inactive for the hydrogenation of monoolens to parains, at temperatures of from 100 to 800 F., pressures of from atmospheric to 600 1bs./sq. in. and at feed rates of from 0.1 to 5.0 v./v./hr, thereby selectively converting the diolenic and acetylenic components to monoolens.
References Cited in the le of this patent UNITED STATES PATENTS 2,206,200 Ocon July 2, 1940 2,283,854 Friedman et al. May 19, 1942 2,289,716 Marschner July 14, 1942 2,339,246 Bates et al. Jan. 18, 1944 2,359,759 Hebbard et al Oct. 10, 1944 2,472,254 Johnson June 7, 1949 2,542,970 Jones Feb. 27, 1951 2,636,844 Kimberlin et al. Apr. 28, 1953

Claims (1)

1. A METHOD WHICH COMPRISES COKING A PETROLEUM RESIDUUM STOCK IN A FLUIDIZED BED OF SUBSTANTIALLY INERT CONTACT MATERIAL AT TEMPERATURES OF 1000-1200* F. AND SUBJECTING A MIXTURE OF THE REACTION PRODUCTS FROM SAID COKING PROCESS BOILING BELOW ABOUT 430* F., AND A NAPHTHA STOCK RICH IN NAPHTHENES TO TREATMENT IN CONTACT WITH A CHROMITE HYDROGENATION CATALYST EFFECTIVE FOR THE CONVERSION OF DIOLEFINIC AND ACETYLENIC COMPOUNDS TO MONOOLEFINS BUT WHICH IS RELATIVELY INACTIVE FOR THE HYDROGENATION OF MONOOLEFINS TO PARAFFINS THEREBY SELECTIVELY CONVERTING THE DIOLEFINIC AND ACETYLENIC COMPONENTS TO MONOOLEFINS.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2910427A (en) * 1954-07-07 1959-10-27 Phillips Petroleum Co Coking of hydrocarbon oils
US2934574A (en) * 1957-01-11 1960-04-26 Tidewater Oil Company Selective hydrogenation of butadiene in admixture with butenes with cobalt molybdateas catalyst
US2943996A (en) * 1957-06-10 1960-07-05 Universal Oil Prod Co Reforming process
US3108947A (en) * 1959-11-26 1963-10-29 Shell Oil Co Process for the selective hydrogenation of diene-containing gasoline
US4528088A (en) * 1983-11-30 1985-07-09 Exxon Research And Engineering Co. Coking with solvent separation of recycle oil using coker naphtha and solvent recovery
US4530755A (en) * 1983-10-31 1985-07-23 Exxon Research And Engineering Co. Coking with solvent separation of recycle oil using coker naphtha

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US2206200A (en) * 1937-07-17 1940-07-02 Ernest A Ocon Process for cracking and hydrogenating bituminous oils
US2283854A (en) * 1940-07-05 1942-05-19 Universal Oil Prod Co Conversion of hydrocarbon oils
US2289716A (en) * 1939-10-19 1942-07-14 Standard Oil Co Catalytic motor fuel production
US2339246A (en) * 1940-08-02 1944-01-18 Houdry Process Corp Production of low boiling hydrocarbons
US2359759A (en) * 1939-04-22 1944-10-10 Dow Chemical Co Purification and production of olefins
US2472254A (en) * 1944-08-22 1949-06-07 Shell Dev Apparatus and method for carrying out catalytic reactions
US2542970A (en) * 1946-06-15 1951-02-27 Standard Oil Dev Co Refining of cracked naphthas by selective hydrogenation
US2636844A (en) * 1950-08-29 1953-04-28 Standard Oil Dev Co Process for the conversion of reduced crudes in the presence of an added naphtha

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2206200A (en) * 1937-07-17 1940-07-02 Ernest A Ocon Process for cracking and hydrogenating bituminous oils
US2359759A (en) * 1939-04-22 1944-10-10 Dow Chemical Co Purification and production of olefins
US2289716A (en) * 1939-10-19 1942-07-14 Standard Oil Co Catalytic motor fuel production
US2283854A (en) * 1940-07-05 1942-05-19 Universal Oil Prod Co Conversion of hydrocarbon oils
US2339246A (en) * 1940-08-02 1944-01-18 Houdry Process Corp Production of low boiling hydrocarbons
US2472254A (en) * 1944-08-22 1949-06-07 Shell Dev Apparatus and method for carrying out catalytic reactions
US2542970A (en) * 1946-06-15 1951-02-27 Standard Oil Dev Co Refining of cracked naphthas by selective hydrogenation
US2636844A (en) * 1950-08-29 1953-04-28 Standard Oil Dev Co Process for the conversion of reduced crudes in the presence of an added naphtha

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2910427A (en) * 1954-07-07 1959-10-27 Phillips Petroleum Co Coking of hydrocarbon oils
US2934574A (en) * 1957-01-11 1960-04-26 Tidewater Oil Company Selective hydrogenation of butadiene in admixture with butenes with cobalt molybdateas catalyst
US2943996A (en) * 1957-06-10 1960-07-05 Universal Oil Prod Co Reforming process
US3108947A (en) * 1959-11-26 1963-10-29 Shell Oil Co Process for the selective hydrogenation of diene-containing gasoline
US4530755A (en) * 1983-10-31 1985-07-23 Exxon Research And Engineering Co. Coking with solvent separation of recycle oil using coker naphtha
US4528088A (en) * 1983-11-30 1985-07-09 Exxon Research And Engineering Co. Coking with solvent separation of recycle oil using coker naphtha and solvent recovery

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