US2334306A

US2334306A - Cracking hydrocarbon oils

Info

Publication number: US2334306A
Application number: US465949A
Authority: US
Inventors: Barron Joseph Mason
Original assignee: Texaco Inc
Current assignee: Texaco Inc
Priority date: 1942-11-18
Filing date: 1942-11-18
Publication date: 1943-11-16
Anticipated expiration: 1960-11-16

Description

Nov. 16, 1943. J. M. BARRoN CRACKING HYDROCARBON OILS Filed Nov. 18, 1942 Hls ATTORNEY Patented Nov. 16, 1943 lJoseph;Mason lfarron,` `Port Tex., assigner to The Texas Company,`Ne'w`fork, Y., acor f poration of 'Delaware t :Application November 18, 1942; Seri "4 91eme t rc1- 1964er This' invention `relates to al combination "cata'"` I lytic crackingand thermal 'cracking process for the production'of a maximum yield cf high anti# knock gasoline or motor fuel.` I f l The'`` invention contemplates n a method of processing charging stocks,y such as crudepetroleum or topped or reduced'cludain a unitary operation Ain which certain fractions* are subjected to catalytic cracking,` certainfra'ctions arefsub jected to'thermalcracking4 and residual products of the thermal cracking are subjected to flash distillation or coking. In accordance with the invention the hot products from the catalytic cracking step arecombin'ed with vapors from the I coking step in a dephlegmating `Zone into which charging stock is introducedto thereby accomplish fractionation of the charging stocktogethe'r with"products from the coking andV catalytic cracking operations. 'I'he higher boiling fractions separated out in thedephlegmating zone are com-` bined with the 'hot eliluent from a heating Tzone of the thermal cracking step andv thecombinedY products subjected to pressure cracking and sep` arated'into vapors andresidue. The separated vapors arefractionatedto obtain higher boilingV fractions,`Y intermediate boiling fractions and lower boilingfractions. The higher boiling frac" tions are cycled to the heating zone of Vthe thermal cracking stepand the interrnediate'` boiling fractions are directed' to the catalytic cracking step. The vapors fromth'e catalytic cracking and coking steps, which remain uncondensed after thede-v phlegmation with the charging stock,` are com densed to obtain a distillate `-whichis 'directed to the fractionating `zone of the thermal cracking operation 'or are subjected to further fractionation toobtain selected fractions some o'which are passed to the heating zone of the thermal cracking step and others of which are directed` to the fractionator of the thermal cracking step.

v For the purpose of more fully disclosing the inventionvreference 4is had to the accompanying drawing* which is a 'iiow diagram illustrative of the invention. f

In' the thermal cracking step hydrocarbon oil isl subjectedto a cracking temperature ina heating coil I disposed in a furnace- II. Theheated products passthrough a transfer linel I2 to a reaction chamber I3. Thereaction chamber is insulatedk to reduce -radiationlosses and-the hydrocarbons therein are subjected to I cracking temperature Vunder superatmospheric pressure while simultaneously being separated into-vapors,v and liquid' residue. vfIhe separated vapors` pass through a vapor line I4' to a fractionator` I5 CIT a1 No. $5,949 I Which'is `formed with a primary fractionating sec- L *tion ISA and a secondary fractionating section I5B separated by a; trap-out tray IB. Each of the 4fractionating sections. I5A and IEB are providedwith suitable vapor-liquid contact elements,

preferably" disc and doughnut trays inIBA and' `ing coil IU. The intermediate fraction collected in tray I6 is directed to the'catalytic cracking` steplas is-hereinafter described. Vapors uncon- I densed in the frictionating section I5B pass toa I I condenser 'I9 'thence to' a distillate drum orgasV separator 20. I

thelresidual, constituents are 4converted to coke by means of contained heat. In practice aplu.V

ralityof coking drums are employed to enable the removal of the cokeLwithoutdisturbing-the` continuity ofl the complete process. The vapors produced in the coking operation pass through a vapor 1in'e"2 to a fractionator 25. tionator 25 is preferably formed with a primary section 25A and a secondary section 25B separated by a trap-out tray 26 and the coke Still vapors are preferably subjected to a primary dephlegmation in section 25A in order to separate out from the vapors thevery heavy constituentswhich are ex' tremely valuable as fuel oil, the heavy tarry condensate formed being removed through a line 21. In an alternative operation, when it is not. desiredto reduce the thermally cracked residue to coke,A the vresidue withdrawn through line 2I may bedirected through a by-pass line 28 and `passed directly` to section 25A wherein the residue is flashed,l the flashed residue being withdrawn through line 21. 1

The vapors from the coking or flashing opera` tion. which are uncondensedin the dephlegmator 25A pass to the dephlegmating section 25B into which charging stock, such as crude petroleum orl topped or reduced crude, is `introduced by a pump ZSand `line Bil. :In the dephlegmating section 25B the vapors from the coking or flashing operation together with products fromY the catalytic cracking operation, as is explained hereinafter', are 1dephlegmated with the charging The frac-1;

vtinuityofthe complete process.

stock. The higher boiling fractions collected on vthe tray 2'6 lareI withdrawn by a pump 3| `and i directedr through a line 32 tothe transfer line I2 or to the reaction chamber I3 so as tov combine these fractions with the effluent from-the heating coil I for thermal cracking in the reacand directed by a pump 34 vto a heating coil "'such as 1000 F.-1030 F. The efiluent from the heating coil is, combined With the bottoms from f i dephlegmator 25B and the mixturesubjected to Q thermal cracking-in'reaction chamber I3 under' 35 disposed in a furnace 36 wherein the oil is cracking.l The heated stream `passes from v the heating coil through a line 3'I'to aV reaction cham# ber 38 wherein the stream is "contacted 'with' a suitable catalyst adapted to promote conversion into lower boiling hydrocarbns. In. practice a pluralityof catalytic reaction chambers are used so as to provide for the reactivation or'regenerationl of. the, catalyst without disturbing the' conwherein it is heated suiiiciently to lmaintain raised to the desired temperature for the catalytic cracking temperatures of the order of 850 F.-

1050 F., preferably temperatures of about 910 V F.1000 F., in the catalyst case 38 containing a catalyst such as a synthetic silica-alumina cat- Best results are obtained by carrying av tonator IEA is`recycled' to the heating coil lII) a wherein it is subjected to crackingftemperatures KJsuperaftmosphe'ric j pressure rsuch as ZOO-600 l p. s. i.k at cracking temperatures upwards of 900'.

Vi F.l Separation ,ofvapors from liquid residue ocvThe f catalyst consists adv.antageously,`oiagsyn;v l

Athetic silica-alumina type. ofcatalyst. Various.

acid-treated andgmetalesubstituted claysg Such as the gSupervFiltro-ls and l,acid-treated and metalsubstitutedf naturaly or. artificial zeolites,` such as. thev artiflcialf zeolite known as` Doucil rmay be employed. Various metals suchasuranimn, inolybdenum, manganese, i lead, zzincl; zirconium, nickel.. and the like, may be substituted .inf the clays or z eolites.'` Likewise,thecombination of certain acid-treated active claysl of the charac.-

ter ,of Filtrol, together.. with addedjlproportions of alumina Y or silica. or; both may be"employe,d..

Alumina alone may beused undercertain condi;-I

v` tions. The synthetic alumina ,catalysts can abe improvedby the addition of other v.constituents such as zirconium oxide or mclybdenunrioxide.A

The hot eiuent from the catalytic; cracking step is directed through a line- 39.' to the denhlegf: mating section yP3513 whereinthe hot catal'yticallycracked products are combined with the dephleg-f4 mated;v coke still vapors and serve to vaid. :in .ac complishing the.V vaporization. ofthe charging stock'introduced:through line. 3&1..v

The vapors uncondensed inthe dephlegmating v"zoneyZBpass through a vapor lineJAiJ to Yacc-nvpers owing through line 40 are diverted through a. line to a fractionator 49., .'I'hevapnrsl are subjectedfto fractionationiin fractionator 4'9 to separate higher boiling reux ,condensate from' lighter constituentsa The lighter.r constituents are remo-ved as: avapcr through a line .50 and passed thence to the condenser coil 4I anddistillate druml l2 While the higher boiling'r eendensate is directed by a pump 5I. through :a line- 52xto the recycling line I8 or to the lheating coil In practicing the inventicna llight gas oil stock frornggthe fractionator IEB, Vas' withdrawn from tray I his passedthroughtheheating coiL 35 cumulation 'of liquid in thereaction, chamber., j

A portion of the vaporssuicient to accomplish autogeno-us coking of the residue-is. included With .l

the withdrawn vapors and themixtureisiiashed into .the coking drumwherein avr low pressure of about 5e50 .p s, i. maintained.; Bywithdrawing themixture trom.V the reaction chamberat temperatures of about 910 F.-925? lF. cc nversion toe marketable coke by means of -thecontained heat is readily Vaccomplishedgin the cokingchamben 4 The hoteiiiuent fron1`the1catalytic cracking opg .eration is directed tothedephlegmator 25E-into..

which topped crude' is l introduccd.4 v,This .de-,l phlcgmatcr alsov receives-the dephlegmated cokey stillyapors from dephlegmator 25A. Thef rac-A rtion which is. collected on-the tray 26 includes residual constituents ofthe crude chargeand con fuel;oilproduct..` -Whilef.l'..ha.ve describeda particularfembodiment de nsedconstituents from the-cokingcperatiom- Ordinarilycnly a minimum, if anyi ofccnstituents' d from the catalytic cracking Aare includedfinz-thise fraction, since the bulk of the catalyti'cally cracked. products distill over toV the subsequent condensingoriraction'ating zones'. The overhead VLQQrs fIfQm the dephleginater.

25B, comprising a mixture: of straight'run con'.r stituents and constituents from the coking, and

catalytic cracking operations, are: condensed and directed asa reflux to; the tower I 5.H Inthis wey straight run,- gas-cil constituentsas wellgasf gas oil constituents from thefcoking and catalytic' cracking operations, aire combined withthe thermally cracked vaporsr in thetower I5- andsubject-ed, to fractionation vthereinvvith the resultl tnatthe nent gasoiifpacuon collecting-in the trayY I6 will include not onlyconstituents from,

the thermal cracking. operation' but also large proportions; of` constituents i rom the coking andi cati-1 alytic lcracking operations as Well ajs straight-run fractions from the topped crude.- The voi/'erl'iead distillatefrom thef'tower l5 will include gasoline from the. thermal cracking-,. catalytic cracking and coking operations.

of my-inventicn forl purposes of 'illustratonysit Ordinari-1y t-isadtantascw Y to. reduce the pressure inthe towerjlfbelowfthat obtaining in the reaction chamber I1l. '-.,lor-ex 1 ample, withapressure ofelolbs. in .the reaction chamberthe pressure in` the fractionator may be mayr` bee-Withdrawn Vas a;

should be understood that various modifications and adaptations thereof, which will be obvious to one skilled in the art, may beA made within the i spirit of the invention as set' forth in the appended claims.

I claim:

l` In the conversion of hydrocarbon oils the process that comprises subjecting hydrocarbon oil to thermal cracking in a heating zone and a communicating reaction zone maintained under superatmospheric pressure and Ywherein separation of vapors from liquid residue takes place, passing resultant separated vapors to a fractionating zone wherein the vapors are subjected to fractionation to separate a higher boiling fraction from intermediate and lo-wer boiling fractions, recycling said higher boiling fraction to saidheating zone, withdrawing residual constituents from said reaction zone and subjecting them to coking in a lower pressure ooking Zone, directing the intermediate fraction from the aforesaid fractionating zone to a catalytic cracking zone where`` in it is subjected to catalytic cracking, combining the resultant products of theI catalytic cracking zone with vapors evolvedy in the coking zone and dephlegmating the resultant commingled vapors with a residual oil charging stock in a dephlegmating` zone, withdrawing the resultant bottomsfrom said delphlegmating zone and combining the bottoms with the effluent from the aforesaid heating zon-e for thermal cracking in the communicating reaction zone, subjecting uncondensed vapors from said dephlegmating zone to condensation to produce a condensate' and directing said condensate to theaforesaid fractionating zone;

2. In the conversion of hydrocarbon oils the process that comprises subjecting hydrocarbon oil to thermal cracking in a heating zone and a communicating reaction zone' maintained under lsuperatmosphericV pressure and wherein separation of vapors from liquid residue takes place, passing resultant separated vapors to afractionating zone wherein the vapors are subjected to fractionation toseparate'a higher boiling fraction from intermediate and lower boiling fractions, recycling said higher boiling fraction to said heating zone, passing liquid residue from said reaction zone together withra sufficient portion of vapors to accomplish cokingv to alower pressure coking zone wherein autogenous coking takes place,`subject ing the vapors from the coking zone to a primary dephlegmation to produce a heavy tarry condensate, passing the dephlegmated vapors to a secondary dephlegmating zone, directing intermediate fractions'from .the aforesaid fractionating zone to a catalytic cracking zone wherein the oilv is subjected to catalytic cracking, passing the resultant products of the catalytic cracking to said secondary dephlegmating zone, introducing a residual oil charging stock to said secondary dephlegmating zone, withdrawing .resultant bottoms from said secondary dephlegmating zone municating reaction zone maintained under su- 3. In the conversion of hydrocarbonl oils the process that comprises subjecting hydrocarbon oil tol thermal cracking in a heating zone and a comperatrnospheric pressure and wherein separation of vapors from liquid residue takes place, passing resultant separated vapors to a fractionating zone wherein thevapors are subjected to fractionation to separate a higher boiling fraction from intermediate and lower boiling fractions, recycling said higher boiling fraction to said heating zone, passing liquid residue from said reaction zone together with a sufficient portion of vapors to accomplish vcoking to a lower pressure coking zone wherein autogenous coking takes place, vsubjecting the `vapors frompthe coking zone to a primary dephlegmation to produce a heavy tarry condensate, passing the dephlegmated vapors to a secondary dephlegmating zone, directing intermediateV fracboiling distillate, directing saidA higher -boiling process that comprises subjectinghydrocarbon oil and combining the bottoms with the'efiluent from tions'from the aforesaid fractionating zone to a catalytic cracking zone wherein the oilisfsubje'cted to catalytic cracking, passing the resultant products of the catalytic cracking to said secondaryv dephlegmating zone', introducing a residual oil charging stock to said secondary dephlegmating zone, withdrawing. resultant bottoms from said secondary dephlegmating zone and combining the .bottoms with the effluent from the aforesaid-heating zone for thermal conversion in the communicating reaction zone, subjecting uncondensed vapors from said secondary dephlegmating zone tor further fractionation to separate higher boiling reflux'condensate from a lower condensate to the aforesaid heating zoneand directing the lower boiling distillate to the aforesaid fractionating zone.

4. In the conversion of hydrocarbon oils the to thermal cracking in a heating zone anda communicating reaction zone maintained under a superatmospheric pressure and wherein separation Y of vapors from liquid residue takes place, passing resultant separated vapors to a fractionating zone wherein the vapors are subjected to fractionation to separate a higher boiling fraction from intera mediate and lower boiling fractions, Yrecycling saidhigher boiling fraction to said heating zone, withdrawing liquid residue from said reaction zone and subjecting it to flashing to separate aresidue from flashed vapors, directing intermediate fractions from said fractionating zone to a catalytic crackiing zone wherein the oil is subjected to catalytic cracking, combining the resultant products ofthe Icatalytic cracking with the flashed vapors in a dephlegmating zone, introducing a residual oil charging stock to said dephlegmating zone, withdrawing the resultant bottoms from said dephlegmating zone and combining the bottoms` with the effluent from the aforesaid heating zone for thermal cracking in the communicating reaction zone, subjecting uncondensed vapors from` JOSEPH MAsoN Brunson.v