US2343848A - Cracking and coking hydrocarbon oils - Google Patents

Description

Mardi 7,1944. `.L M. BARRoN 2,343,848

CRASKING AND GOKING HYDROCARBON OILS Fild DBC. 151,v 1940 2 Sheets-Sheet 1 FRACTIONATORS JszPH MAsoN BARoN IN VEN T 0R BY www H/SA TTRNEY 2 Sheets-Sheet 2 Much 7, 1944.

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JosEPH MASON BARIUM N'VENTOR HIS A TT ORNE Y Patented Mar. 7, 1944 caAoKrNo vAND coKrNG nmaocAaoN oILs l Joseph Mason Barron, Port Arthur, Tex., assigner, by mesne assignments, to The Texas Company, New York, N. Y., a corporation of Delaware Application December 31, 1940, SerialNo. 372,451

12 Claims.

This invention relates to the cracking and coking of. hydrocarbon oils and has particular reference to certain novel improvements in which cracked residue is reduced to coke in such a way as to avoid priming in' the looking zone and in which the vapors evolved in the coking operation are dephlegrnated and fractionated under conditions to avoid coking in the dephlegmating and fractionating portions of the system.

The invention contemplates a process in which hydrocarbon oil is heated to a cracking temperature and' directed into a reaction zone wherein the oil is subjected to cracking conditions of temperature and pressure and wherein separation of vapors from liquid residue takes place, in which the liquid residue together with a portion of the-vapors sufficient to effect cokingis flashV distilled to a coke residue While the remaining vaporsr are separately withdrawn from the reaction Zone and directed to the dephlegmating portion of the system and in which the vapors evolved from the coking zone are dephlegmated under conditions in which heavy or tarry condensate separated out from the coke still vapors is cycled to the dephlegmating zone to increase the liquid movement therein and inhibit the formation or deposition of coke.

The invention has particular reference to that type of pressure cracking and coking .process in which a cycle condensate is passed through a '13"0 heating coil wherein it is heated to a cracking temperature, the resultant heated stream combined with a heavy stock such as topped or reduced crude and conversion of the commingled M products carried on in a reaction zone and in '35 which the residual products from the cracking operation are passed to a coking Zone for conversion to coke. It has been found that when the total products from the reaction chamber,

that is, all of the liquid and vaporous constitu- "40 ents, are delivered to the coking drum that conversion to a coke residue may be accomplished, but such operation' necessitates the maintenance of relatively low charging and recycling rates in order to avoid priming in the coking drum'. Vl45 When an operation is carried on in which separation of vapors from liquid residue takes place in the cracking reaction chamber and when only the residue is passed to the coking chamber the autogenous heat of the residue is insuflicient cient to effect cok'ing for the production of 55` takes place.

marketable coke. To overcome the heat deficiency in the residue resort has been had tothe lay-passing ofa portion of the heated stream from the condensate heating coil around-the reaction chamber and into the `coking drum but this operation is disadvantageous because of the resultant reduction in the quantity of the heated stream for combining with the heavy stock or black oil which has necessitated that such heavy stock or black oil be passed to a heating coil before being combined with the cycle condensate stream..

naccordance with my invention a .portion of the vapors is withdrawn with the residue from the reaction chamber in quantity suicient to effect coking but without' priming in the coking drum and: the vapors from the coking operation are dephlegmated in the presence of a continuous stream' of'liquid produced by cycling heavy condensate through the dephlegmating Zone. By accomplishing thecoking operation with the inclusion of a portion of thevapors in the residue passed to the coking drum it is possible to materially increase the recycling rate, that is, the rate of cycle condensate .passed to the heating zone, while still avoiding priming in the coking drum. The result is that there is a greatly increasedvolumeof high temperature vapors entering the dephlegmating portion of the system, but cokingtherein is eiectually prevented in accordance with the invention by materially increasing the quantity and rate of liquid ow through the zone wherein the vapors from the coking operation are primarily dephlegmated. This increase in'liquid flow through the primary dephlegmating zone is accomplished without any corresponding increase in cooling applied thereto. While suincient cooling is applied to effect'the desired con-y densation, a rate and volume of liquid 'ow through this primary dephlegmating Zone is maintained soy as to prevent coking, while still enabling the delivery of the uncondensed vapors from the primary dephlegmatingzone at ample temperature to effect the desiredsubsequent distillati'on'v and fractionation.

More specifically the invention contemplates a process in Whichl cycle condensate is passed through a heating' zone wherein it is heated'to a cracking temperature, the resultant heated products combined with oil for cracking in a reaction zone wherein separation of vapors from liquid residue takes place, liquid residue together with a portion'of the vapors withdrawn from the reaction zone and-the mixture passed to a coking'zone wherein autogenous coking remaining vapors are separately withdrawn from the reaction zone and the liquid oW therein and inhibit formation or LTI tion I9 separated by a trap-out tray 20. Vapors from the coking drum I6 pass through a line 2l, in which may be positioned a valve 22, to the primary dephlegmating section I9 which is conveniently supplied with baiiles or disc and doughnut elements 23. The separated vapors from the reaction chamber I3 pass through Aa line 24 and pressure reducing valve 25 to the dephlegmating 26 may be provided for conducting liquid from the trapout tray 20 to the dephlegmating section deposition of coke, while the'renaining portion.) of the tarry condensate is withdrawn as a dis-v tillate fuel oil product. The vapors from this primary dephlegmating zone are passed to aV secondary dephlegmating zone into which also the separated vapors from the reaction zone are `introduced and wherein the vapors are dephlegmated with charging stock such as topped or re-v with the charging stock and a resultant mixtureV of condensate and unvaporized chargingstock combined with the heated products from the cycle condensate heating zone forpreaction in the reaction zone. V

' The/invention, furthermore,contemplates the flashing of the heavy or tarry condensate produced in the primary dephlegmating zone to form a nal fuel oil product of desired gravity or flash test and the reuxing of the flashed diswhich the vapors from the coking operation and pressure cracking operation are fractionated.

For the purpose of more fully explaining the invention reference is now had to the accompanying drawings wherein Fig. 1 is a diagram- 5.0

from a source hereinafterexplained is heated to I,5,5 Y`a ,cracking temperature in' a -heating coil ID mounted in a suitable furnace I I,and the heated products pass through a transfer line I2' to a reaction chamber I3 rwhich is suitably heat in-A sulated and wherein separation of vapors from .60

liquid residue takes place. Liquid is vprevented from accumulating in the reaction chamber I3 by une rapid withdrawal of au the liquid together with a portion of the vapors; The mixture is passed through line; I4 and pressure reducing 165r valveiI5,l thence to coking chamber I6 wherein the residue is converted to coke by means of its contained heat. `In practice a plurality of coke drum'srar'e'employed so that While one is on stream the other or others may be down for r7.0

cleaning and thus continuous operation as re'- gards the complete process is maintained. The fractionating portion of the system includes a: dephlegmator or fractionator I1 provided with an upperV section I9 and a lower sec- .75 heating coil- IIl. The uncondensed vaporspass section I8 which is suitably equipped with disc and doughnut trays 21. A valved runback line vI 9 for reiiuxing therein.

Bottoms from the primary dephlegmator I9 fare withdrawn through a line 28 and a circulatingv pump 29, having its intake line 3U communieating with the line 28 and its discharge line 3| extending to the upper portion of the dephlegmator I9, is provided for continuously circulating a portion of the bottoms through the dephlegmator. By insulating the pump and circulating linesl it is possible to circulate this liquid without any'substantial cooling and it is preferable jto carry on the circulation without any material cooling so that the increased flow of liquid over the baflles 23 is not accompanied with coolingv corresponding to the increased flow. For accomplishing the cooling which may be desirable it is preferable to employ separate reuxing means which is described hereinafter.

Charging stock is introduced by a pump 32 through a line 33 to the fractionating section I8 being preferably admitted to an upper portion thereof. The charging stock serves to dephlegmate the vapors in dephlegmator I8 andthe resultant commingled reflux condensate and unvaporized charge is Withdrawn from tray 20 through a line 34 and is directed by a pump 35 through a line 36 to the transfer line I2 or to the reaction chamber I3. When running to coke and distillate fuel oil the valve in run-back line 26 is closed and all the liquid collecting on tray 20 may be directed by the pump 35 to the heater transfer line I2 or reaction chamber I3, while the tillate in the fractionators or dephlegmators in 45 fue] oilv may be withdrawn through the line 28 and a portion of the tarry condensate continuously cycled back to the dephlegmator I9 to wash thebailies therein. When running to coke only the valve in run-back line 26 is open so that the mixture of reux condensate and unvaporized charging stock may flow into section I9 to dephlegmate the vapors therein and form a final mixture of reflux condensate and unvaporized charging stock which is passed through line 28 and a by-pass line 28-A to line 34 thence through pump 35V and line 36 to the heater transfer line ,I2 ory reaction chamber I3. In the coke only operation the trapout tray ZI) is unnecessary but lin such operation it is desirable to introduce the vapors from the coking drum to a lower portion of the towerA I 'I and subject the vapors to Vdephlegmation and then combine the dephlegmated vapors with the vapors from the reaction chamber I3 for dephlegmation. A- portion of the mixture of Vheavy condensate and unvaporized charging stock is continuously cycled back to the dephlegmator I9 to wash the baffles therein.

Uncondensed vapors from the tower I1 pass through a vapor line 31 to a' fractionating tower 38 which is conveniently equipped with bubble trays 39 and which-may be supplied with conventional cooling or reuxing means not shown. .Re-

flux condensate is drawn from the tower 38 by ya pump 4I] and directed through a line 4I to the tor 43 wherein the distillate productiecollectedf' The line 28'1 is shown provided with a pressure; reducing valve 44' and. extendingv to a flash still 45' whereinthe heavy tarry distillateis flash dis-E tilled to produce a residue of desired gravity or asli test. The' resultant residue is withdrawn" through a line 46 and the separatedv vapors are subjected to such fractionation or dephlegmation as may be desired in the upper sections ofthe; tower 45. The overhead vapors pass toacondenser 4l andthe flash distillate is collected inra." receiving drum 48. This distillate may be di?. rected by a pump 49 through a line 50 to the fractionator 38 as a reflux therefor. Additional cooling may be supplied to the tower 38 by conducting a portion of the reilux condensate from the tower through a cooler 5I and thence by'a pump 52 and une 53 to the lme- 50. The uness may beprovided with abranch line 54 extending tov the upper portion of dephlegmator I9, or to the line 3l, for supplying a cooling reflux to the dephlegmator I9.

In the drawings the cracking chamberv I3, is`

shown as an up-iiow chamber, although a down'- iioW chamber may also be employed in thepractice of the invention. -In the down-now operation the products from transfer line I2 including the black oil from line 36 may be introduced atl the top of the reaction vchamber and flow downwardly therein, themixture of liquid residue and vapors being withdrawn from the bottom of. the chamber while the separate stream of vapors is Withdrawn from a lower intermediateportion of the chamber above the point of residue withdrawal. While the down-flow operation has an advantage in providing good contact between the i constituents from the heating coil I0 and the blackl oil stream there is a tendency for the separate vapor stream to contain quantities of entrained tarry material. In another. method of operation contemplated the products from transfer line I2` including the constituents from line 36 are admitted into a downflow reaction chamber in which liquid is prevented from accumulating kand the productsfrom which. pass to a succeeding upflow chamber; the separate stream oi'vapors being taken oir from the top of the upow chamber to the fractionator and thev mixture of liquid residue and vapors being withdrawn from the bottom of the upflow reaction chamber and passed to the coking drumv I6. When operating with the upflow chamber, as

illustrated, it is advantageous to spray the wall` of the chamber'with a portion of the reflux condensate from the tower 38.

In practicing the invention the'superclean cycle condensate from fractionator 38 is subjected to cracking at temperatures of the order of 1,000 to 1050 F. preferably under reasonably high pressures such as 400-800 lbs. in the -heatingcoil III I9 and upon being commingled with the black y cil stream is subjected to cracking in` the reaction. chamber at temperatures in excess M1900 F. under superatmospheric pressures such as 3D0-500 lbs. Liquid is prevented from accumulating in the reaction chamber, the mixtureof liquid and vapors being rapidly Withdrawn and passed to the coking chamber while the separate vapor stream is passed to thefractionatingportion of the system. A temperature approximating 910 F. is recommended for the mixture of vapors and residue in the line I4, with the temperature in the reaction chamber I3 being somewhat higher. Although the pressure is lreduced in thecoking drum it is recommended thatsuperatmospheric pressures of approximately l00 lbs. or higher be-malntained. therein; with pressures of 350 to 400 lbs. in the reaction chamber pressures yof about 150-1755. lbs. are very satisfactory in the coking drum.y The major. portion of the vapors from thereaction chamber flows through the vapor line while `only a minimum proportion oi the vapors is needed for admixture with the residue to accomplish the coking thereof. The quantity of vapors required to be included in the residue being Withdrawn to accomplish coking is dependent upon the temperature lin the reactionv chamber andit is desirable to maintain as high a temperature as possible in the reaction chamber to keep the quantity of vapor withdrawn'with the residue. at a minimum. Ordinarily a quantity of vapor of the order of 1'0%-20% of the quantity of vapors owing from the reaction chamber will be foiund adequate to accomplish coking without priming. The amount. required can readily be controlled by observing the temperature in the transfer'line tothe coking drum or in the coking drum itself. The temperature required for coking will vary'with the pressure used in the coking operation and somewhat with the character of the stock. The temperature will generally be in excessof 825 F. and normally will, be approximately within arrange of about 840 F. to 885" F. A temperature of 850 1i'.v under 1-50-175 lbs. pressure has been found verysatisfactory. Under the conditions outlined coking is readily accomplished to yieldl a marketable coke while avoiding priming from thecoke drum. Thepressure in the dephlegmator or fractionator I1 willbe approximately the same as that'in the coke drum or if desired somewhat lower. When running to coke only, thatis, when passing theA mixture of. heavy reux condensate and unvaporized charging stock from dephlegmator I9 to the reaction chamber, itis desirable to lmaintain a temperature in the bottom. of the dephlegmatingsection I9 as high as practicable without coking therein. Temperatures as high as 810820 F. inthe bottom of. dephlegmator I9 have been successfully employed. When running to coke and fuel oil;` i. e., when withdrawing from the system the bottoms from dephlegmator I9 and directing the liquid from tray 20 to the reaction chamber it is. generally necessary to maintain somewhat lower temperatures in section I9, such as 790 F.800 F..

A portion of the .bottoms from dephlegmator I9 is continuously cycled by the pump 29` over the baiilesA 23 therein to maintain a .liquid flow therein which prevents deposition ofv coke. The-circulation is so conductedas to keep the circulating lines open and hot and provide suicient flow in the dephlegmator to preventcoking. The necessary coolingmay beA supplied by reiiuxing a relatively small quantity or' cooled'distillate through line 54. The rate; of iiow and volume of. het4 liquid. circulated to. the dephlegmator' is entirely out of proportion tothe amount of lcoolingssupplied. The Yrateof circulation of the bot'- toms from dephlegmator I9 is of. the orderof 10-25L times the rate of cooling oil supplied. When running to coke and distillate fuel oil. that is, when drawing oi tarry condensate from dephlegmator I9 and' withdrawing the mixture of reflux condensate and unvaporized charging stock. from tray 29 for ypassage to the reaction chamber, the rate of the hot recycle Wash will ordinarily exceed the raw oil charging rate as;

for example 2007240 lbarrelsper 'hour hot, wash. with charging rates ofl about 160'-190 bbls. per' hour, and theV hot- Wash rate will91`dna'1`y` bei of the order of ionehaltthe recycle rate to the heating coil.v When running to coke only, thatl is, when directing the vmixture'ofreux condensate .and unvaporized charging stock; from'degeously a topped or reduced crude, after sucht preheating as may be desired, is introduced int the dephlegmating section-I8 to dephlegmatethevapors flowing'upw'ardly therein. Gas oilfcon'g'y stituents contained in 'theV crude are .distilled over'. into the tower 38. The unvaporized residual constituents together ,with the: reflux condensate formed in section .I8 is collectedin tray 2 0 at temperatures of the order of 800 F.815 for cycling tothe reactionv chamber for cracking therein.r The practice-of the invention is par ticularly adapted for the treatment lof crude stocks containing maximum quantities of gas-oil. For the lighter stocks containing largev propor-A tions of gas oil such for example as 26-28 A. Pj. I.V gravityV topped crudes'fvpressures lapproximating 400 lbs. are recommended for the reaction chamber whilewith heavier stocks such as a'20 A. P.. I. gravity' reducedcrude the pressure should preferably be lowered to about1200 lbs.

't' Thefvapors passV overhead from the tower I'I at temperatures approximating .710 F.730 `Eto thetower 38 whichV may be maintained at approx'- 'imately the same pressure as that of thertower I'I, although somewhat vlower pressures may be satisfactorily employed; thus, for example, with a'pressure of 150 lbs. in the tower II the tower- 38 maybe held under a pressure of V4135 lbs.v The temperature in the bottom of the tower 38 approximates 660 F.'680 F.l The top temper-f` ature in the. tower is controlledv totake off `the distillateV of the end point desired; thus, a temperature of 390? F. under 135lbs. pressure" may be employed in taking off a 400 end point gasoline distillate. 2 1

Prior to applicants invention it had not been possible to operate to coke and .distillate fuel oil simultaneously without having to heat the' black oil in a separate furnace coil. The practiceV of the invention has made it possible to runto coke and distillate fuel oil simultaneously with charging` rates of the order of :180-200 barrels per hour. The ypractice ofthe invention has made it pos-y sible when running to coke` only-toraise the charging` rate 'from about 80 barrels per hour up to` 125 barrels perhour, eecting an increase in capacity of 55% Without any reduction inv gas'oe linevyield, and in fact, onsome unitstheinvention has I nade it possible to increase the charging rate to -140 barrels perhour, effecting anincrease of '75%- in capacity, alsowithoutreduction in gasoline yield. -p n. Y

`In accordance with .the invention, itY ispossible to include suicient vapor with the residue withdrawn from the reaction chamber to furnish su'fcientheat for coking and yet have the total coking Vdrum input Well below the priming point even at capacities of 200% v'or more over the previous capacity. Previously, for example, when operating on'topped paraflin base crude atre- Y rels perhour. Prior -to applicants invention the limits onpvthe recycling rate, that is, the rate of cycle condensate passed to the heating coil were foundto -berwith various stocks approximatelywithinvthe range 017-230 vor 280 'barrels per hour. The practice o f the invention enables the increasing o fl the recycle rate upto high rates approxrcted to the coking drum I6.

imating 400-500 barrels per hour. 'In viewof the high' recycle ratejthe invention is particularly adapted yforthe processing of light topped crudes containing large proportions of gas oil.

;The following. table presents pertinent data concerning three; typical runs-in accordance with thevinventionroperating on "a parain base re-y duced crude charging stock:

- coke gle Fuel l 'Only' dist', 011,A

run A run. B run C Charge gravity.; -L 26.2 26.2 25. 6 Charge ratebarrels per hour.. 124 166 192 Recycle rate to heating coil .;..do.. 446 479 477 Heating coil outlet temp f .F l, 010 1,015 1, 035 Reactionchamber pressure f pounds per square inch... 400 400 400 Temp.' mixt. of vapors and res. from reac-v tion chamber. .f F 909 u 910 Y 909 Cokedrum press.pounds per square inch.. 175 175 155 Coke .drum temp; .4.1.; '.F S45 A 853 842 lllaclr` oil.recycle rate to reaction chamv ber..' ,l barrels per hour.. 210' 235 280 Hot wash recycle rate..' do.-.. v110 200 240 Inthese typicalexamples of the invention a yieldfof about 55%-60% of gasoline having an octane value 'of 74-77C."F. R. R. was obtained and 4in runs B and Cla' yield of about 15% of distillate'fuelfcilwaslproduced: 11n runs A and B ther-operation" wa'sw'ithga` down-flow reaction chamber and in run'C the oper-ation was with 'an up-iiow` reaction chamber. The quantity of cycle condensate cooling stock introduced to the primary fdephlegmator approximated 5-15 barrels perh'our.V

In the modification of the invention shown in Fig. -2 the vapors from the reaction chamber and thecoking drum are fractionated in entirely separatel fractionating zones. In accordance with this modification the vapors` fromthe reaction chamber I3'are passed to a primary fractionator Ib.' wherein lthe vapors are dephlegmated with chargingstock introduced .by pump 32 through line 33, Vthe resultant mixture oflreux condensate and vunvaporized, charging stock is withdrawn .from the fractionator IBb through line 34h and is directed by pump '35h through line 36h to the transfer line I2 to thus com-bine the mixture with the cycle condensate stream from theI heating coil I0 for cracking in the reaction chamber I3 and the vapors from the primary fractionator IBb are subjected to furtheriractionation in fractionator 38h '.tovseparatelighter'products from a reux condensate whichV is cycled tov the heating coil I.0:by pump 40hthrough -1ine'4!b. -V The residue from the reaction chamber together with aportionof the vapors -suicient to eiect coking is di- The vapors from therV coking drumr are directedy to the separate dephlegmating zone I9 in which the tarry condensate is condensed out and a portion thereof cycled throughthe dephlegmating zone` to increasethe liquid *.ow and prevent deposition of-A carbon therein'in the (manner, that hasv been explained, andthe vapors uncondensed in this dephlegmatchamber frationating zones. Y y Y. y the advantage that `the yield of distillate fuel oil .ingzonc are subjected to further condensation or fractionation in f ractionating zone 18a to obtain a condensate which may be collected in trav lila, while overhead vapors are condensed in condenser .42a and the distillate'iscollected in receiver 43a.

Condensate from tray 20a is directed by apllmp 55 through a line .56 having branches 51 and v58 leading, respectively, to the towers |81; and 381i vand another branch 59 leading to the heating coil I0, so that the condensate may be reflllXBd in the vprimary or secondary fractionating Vzones forth@ reaction chamber vapors or passeddirectly tothe heating zone, while tarry condensate iswithdrawn from the ash dephlegmating zone through line A 28 as adistillate fuel oil product.

of operation facilitates the carrying on ofthe coking operation at relatively low pressures while maintaining higher pressures Vin the reaction The method yhas reduced below about8%A while vthe Inodied operation will permit a reduction incoke yield down to about 2%, .with al corresponding increase di'stillateiuel oil, as .wellas an increasein gasoline yield.

Although aplreferred embodiment ofthe invention has 4been described herein, it will be understood that various changes and Amodifications may be made therein, while securing toa greater or less extent some or all of the benets of A.the invention, ywithout .departing from .the .spirit .and scope thereof.

AI claim:

V1.`In `the conversion of higher boiling hydrocarbon oils into lower boiling ones, the process that comprises combining residual stock jand cycle condensate stock at cracking temperature .for cracking in a reaction zone wherein separation 'of .vapors from liquid residue takesrflplace,

vmaintaining cracking conditions of temperature and pressure in the reaction Zone, withdrawing the liquid residue from the reaction zonetogether with a portion of the vapors anddelivering the mixture of vapors and liquid to a coking `zone lwherein conversion to acoke residue .takes place,

the proportion of vapors so withdrawn with the liquid residue being sufficient to effect autogenous cokingv of the mixture, passing the. evolved vapors from the coking'zone to a primary dephlegmating fzone wherein the vapors are dephlegmatedwith ,the application .of a limited amount of cooling Afluid so that temperatures of the order of ,800 F.

are maintained therein, withdrawing `.a resultant liquid product of dephlegmation from said dephlegmating zone and cycling a portion thereof back to the dephlegmating-zone at a rate approximating 10-25 times the rate of saidcoolingyi'luid to increase the liquid oW therein and prevent coking, subjecting vapors Vuncondensedin said dephlegmatngzone to further fractionation toseparate .a higher boiling condensate from lower boiling products,fheating 4said higher boiling condensate to a cracking temperature :and utilizing This method it as theaforesaifi cycle condensate stock which .is combined h said residnal-stocli for cracking,

separately withdrawing separated vapors from Asaid reaction .acne and subjecting inem to fracseparation .of vapors from .liquid residueialees .place maintaining cracking .conditions of iemperature andpressnrein the reaction zone.. Witn- .drawine tneflicoic .residue vnom :the rcactioneene ,togetherfwitn a portion of the vapors and cle- Vliverine the v mirri-ure of vapors and liquid to a lenig zone ,conversion to a cokcresdne '.talsesrplace, t e, ronortlon of vapors so withdrawn With-.thezliouic resirlnebeins suicient .to .cftect antogenells schine of the mixture, passing the evolved vapors-Iromtneecking Zone to anrim'arrdepnlee eazone-fwhereintne vanorsare dennleemated wvl-1th .the application of a limited amount yo f cooling ilnid so that temperatures .of .the .order ,of 800 -E-.are maintained therein. roth- K drairaine a resultant Vliflllid product of.dennlee mation frcmsal .denhlcelnatinglzone and cycling .a portion thereof nach to ineccnnleernatinezone .ata ratetanproximating 1Q-..25 times the rateof said, cooling nuld to increase the liquid flow .therein vand .prevent cosine. subjecting vapors f uncondensed in said depnleemating Zone to further Yiractionat ion to separate `a higher .boiling Ycondensate from lower boiling products, cycling said higher boiling condensate A to theV aforesaid ;.heati r 1e .zone in which :the condensatc stock is cheated,sera ratclv withdrawing separated .vapors `from :said reaction zone ,and subjecting them to .fractionation to recover a vdesired. product.

3. Inftne :conversionef p higher boiling 1hr-dro.- oarbon oils into lower boiling ones, the :process `-that comprisescombining residual Vst ocka ndcycle .condensate stock :at cracking temperature A@for cracking ima :reaction :cone wherein lseparation .offvapors from liquid residue takes place, maintaininefcracking conditions of temperature and pressurein theV reaction zone, delivering the liquid residue and;aportion ofi-,the --vapors .to a coking -zone whereiniconverson Lto a coke yresidue takes place, the proportion .of Avapors so delivered to .the cokingzone being sufficient to effect :autogenous ,coking vof thev residue, passing the evolved lvapors from thercoking zone to a primary Jdephlegmating :zone wherein lthe .vapors :are de- .phlegmated with the application of a limited amount ofgcooling fluid so that temperatures; of `the order of. 8 00:F. ,are maintainedgtherenwithdrawing: a resultantliguidfproduct Iof .dephlegma- -tionfrom saiddephlegmating Azone and. cyclinga portion thereof back :to the 1 dephlgemating zone at a rirate approximating 10?25 timesftheratle of vsaidcoolingdiuidto increase the: liquidiiowithere in .and prevent v;cpking, l subjecting'. vapors unconedensed @in said ydephlegrnating :zone to further :fractionation to v zseparate a :higher boiling; cona densate from lowerhoilingproducts,Jheatingsaid :higher-boiling condensate toa;.crackingztempera- V,ture and :utilizing it gas-the g aforesaid cycle condensatef stockgwhich is combined with sai-d fre- -sidual stockifornracking, separatelywithdrawing separatedN/aporsgafrorn said reaction; zone andsubjecting them:to fractionationztorecoverLa desired product. f

1.4;., In the conversioni of higher yboiling hydro..

'carbon oils into lower boiling-ones',v the process that comprisespassing Acycle Acondensate to a heating zone wherein it is heated toa cracking temperature, combining Vresultant heated products with oil-for cracking in-a reaction zone-where- `in separation of vapors from liquid residue takes place, maintaining cracking conditions of temperature and pressure in the reaction zone, withdrawing the liquid residue from the reaction-zone together with a'portion of the vapors and delivering the mixture of vapors and liquidV to a coking'zone wherein conversion to a coke residue takes place, the proportion of .vapors so -with- -drawnwith the liquid residue being suliicient'to eect autogenous coking* of the vmixture,` passing the'evolved vapors from' the coking zone to -a primary dephlegmating zone wherein the vapors are dephlegmated with the' application of a limited amount of cooling uid*softhatftemperatures of the order of 800:FLare maintained-therein, withdrawing a'resultant liquid 'product of' dephlegma- Ation fromv said dephlegmating zone andcycling-a portion'thereof backto thefdephlegma'ting zone at arate approximating 10-25 timesv the rate of said cooling uid to increase the liquid -flow there- In the conversion cif` higher boiling hydro'- carbon oils into lowerboiling ones', the process that comprises passingcycleA condensate to' a heating zone 'wherein itris 'heated'to' a cracking temperature, x'combining resultant heated products with oil forcrackingin a reaction zone wherein separation ofvapors from liquid residue takes place', maintaining cracking conditions of temperature and pressure in the reaction'zonerwithdrawing the liquid residue from thereactiongzone` together with a portion of the vapors andldeliverving the mixture of` vaporsand liquid to a coking zone' wherein conversion to a 'cokeresiduetakes place, the proportion of vapors so withdrawn with fthe liquid residue'being sufficientl to effect autogvenous coking of the mixture, delivering the evolved vapors from the coking zone to adephlegmating zone fwherein` the vapors arefdephlegmated with the application of a limited Vamount of cooling lfluid so that temperatures of the order of 800 F. are maintained therein and a tarry condensate is.' thereby separated from the vapors, withdrawing tarrycondensate from said dephlegmating zone and cycling a. portion thereof back to the dephlegmating zone at a rate approximating -25.times the :rate of said cooling fluid to increase theliquidiflow therein and prevent coking, passing vapors from said dephlegmating zone to a second dephlegmating zone, separately withdrawing separated vapors froml the laforesaid reaction* zone! and delivering them to said; second dephlegmating zone; -introducing chargingst'ock into said second dephlegmating zone to dephlegmatevapors therein, withdrawing a resultant mixture. of condensate and unvapor-` ized charging stock from the secondary dephlegmating zoney and utilizing it aslthe oil being comibined wthvthe heated productsfrom the aforesaid heating zone, subjecting vapors fromthe -sec'ondary dephlegmating zone to-.further fractionation to separate a lreux condensate from lighter products and directingI said reux condensate to the aforesaid heating zone as said cycle condensatei 6. In the conversion of higher boiling hydrocarbon oils into lower boiling'ones, the process that comprises passing cycle condensate to a heating Yzone wherein it is heated vto a cracking temperature, combining resultant heated-products with oil for cracking in a reaction zone wherein separation of vapors from liquid residue takes place. maintaining cracking conditionsfof temperature and pressure in vthe'reactionA zone, withdrawing the liquid residue from '-fthe reaction zone together with a portion', of the vapors and-deliver ing the mixture of vapors and-liquid to a coking zone wherein-conversion to' acoke residue takes place, the proportionof vapors so Withdrawn with the liquid residue being suflicie'ntto effect-autogenous coking of the mixture, delivering the evolved vapors from the coking zone to a 'de- 'phlegmating zone, passing vapors from said demat'ing zone, cycling a portion thereof back to the rst dephlegmating zone to increase the liquid flow vtherein and prevent coking, utilizing the'- `remaining portion as the oil being combined with the heated products from4 the aforesaid heating zone, subjecting vapors from the secondary dephlegmating zone to further fractionation to separate areux condensate from lighter products and directing said reflux condensate to the aforesaid heating zone as said cycle condensate.

'7. In the conversion of higher boiling hydro- "carbon oils into lower boiling ones, the process that comprises passing cycle condensate to a heating zone whereinit'is heated to a cracking temperature, 'combining resultant heated products with oil for crackingin a reaction zone wherein separation of vapors from liquid residue takes lplace, vmaintaining cracking conditions of temperature and pressure in the reaction zone, withdrawing theliquid residue from the reaction r zone together -with a portion of the vapors and reaction zone and passing said vapors to a primaryv pressure fractionating zone, introducing charging stock to said-primary pressure fractionating-zone'to rdephlegmate vapors therein, utilizing a resultant mixture ofreux condensate and unvaporized charging stock from said pri- -mary pressure fractionating zone as the oil com- Lbined with the heated products from the aforesaid heatingl zone, subjecting vapors from said primary-pressure fractionating zone to further fractionation to separatea reflux condensate from lighter-products and directing such reiiux condensateto the aforesaid heating zone, passing the evolved vapors from the coking zone to a seplizo'ne 'andicycling 'a Aportion-.thereof back theretol'at arate dephlgmatingzone wherein the vapors are dephlegmated'with'the application of a limited amount of cooling uid so thattemperatures of tion from said dephlegmating Zone and cycling a portion thereof back to the dephlegmating zone at arate approximating -25 times the rate of said cooling fluid to increase the liquid flow therein and inhibit deposition of coke, subjecting vapors from said dephlegmating zone to condensation to produce a condensate and combining said condensate with the aforesaid reflux condensate being directed to the aforesaid heating zone.

8. In a coking process wherein residual proclucts from a pressure cracking operation are subjected to coking and vapors evolved in the coking -the order of 800 are maintained therein, withdrawing. a Aresultant liquid .product of `dephlegmaoperation are subjected to fractionation to obtain a condensate stock adapted for cracking into gasoline constituents, the process that comprises passing the vapors from the coking operation to a primary dephlegmating Zone wherein the vapors are dephlegmated with the application of a limited amount of cooling fluid so that temperatures of the order of 800 F. are maintained therein, withdrawing a resultant liquid product of dephlegmation from the primary dephlegmating Zone and cycling a portion thereof back thereto at a rate approximating 10-25 times the rate of said cooling fluid to thereby establish and maintain a liquid flow therein adapted to prevent coking, passing the dephlegmated vapors from said primary dephlegmating Zone to a subsequent fractie-hating zone wherein the vapors are fractionated to separate gasoline constituents from higher boiling condensate adapted for cracking into gasoline constituents.

9. In a coking process wherein residual products from a pressure cracking operation are subjected to coking and vapors evolved in the coking operation are subjected to fractionation to obtain a condensate stock adapted for cracking into gasoline constituents, the process that comprises passing the vapors from the coking operation to a primary dephlegmating zone wherein the vapors are dephlegmated with the application of a limited amount of cooling iluid so that tempera- ,tures of the order of 800 F. are maintained therein and a tarry condensate is thereby formed, withdrawing said tarry condensate from the primary dephlegmating zone, cycling a portion thereof back to the dephlegmating zone at a rate approximating 10-25 times the rate of said cooling fluid to thereby establish and maintain a liquid flow therein adapted to prevent coking, withdrawing the other portion thereof from the system as a fuel oil product, passing the dephlegmated vapors from the primary dephlegmating zone to a subsequent fractionating zone wherein the vapors are fractionated to separate gasoline constituents from higher boiling condensate adapted for cracking into gasoline.

' 1,0. In a coking process wherein residual products from a pressure cracking operation are subjected to coking and vapors evolved in the coking operation are subjected to fractionation to obtain a condensate stock adapted for cracking into gasoline constituents, the process that comprises passing the vapors from the coking operation to a primary dephlegmating zone wherein the vapors are dephlegmated with the application of a limited amount of cooling oil so that temperatures of the order of 800 F. are maintained therein, withdrawing a resultant liquid product of dephlegmation from the primary dephlegmating a irate approximating 10-25 times the rate of said cooling -oil to thereby establish and maintain "a boiling condensate adapted for cracking into gasoline constituents.

v11. In the conversion of higher boiling hydrocarbon oils into lower boiling ones,'the process f that comprises passing cycle condensate to a heating zone wherein it is heated to a cracking temperature, combining resultant heated products with oil for cracking in a reaction zone, maintaining cracking conditions of temperature and pressure in the reaction zone, expanding resultant cracked products comprising residual constituents into a coking zone wherein conversion to a coke residue takes place, passing evolved vapors from the coking zone to a primary dephlegmating zone wherein the vapors are dephlegmated with the application of a limited amount of cooling fluid so that temperatures of the order of 800 F. are maintained therein and a tarry condensate is thereby formed, withdrawing said tarry condensate from the primary dephlegmating zone, cycling a portion thereof back to said dephlegmating zone at a rate approximating 10-25 times the rate of said cooling fluid to thereby establish and maintain a liquid flow therein adapted to prevent coking, withdrawing the other portion thereof from the system as a fuel oil product, passing the dephlegmated vapors from the primary dephlegmating zone to a secondary dephlegmating zone, introducing charging stock to dephlegmate vapors therein, withdrawing a resultant mixture of reflux condensate and unvaporized charging stock and utilizing such mixture as the oil which is combined with the heated products from said heating zone as aforesaid, passing the dephlegmated vapors from the secondary dephlegmating'zone to a subsequent fractionating zone wherein the vapors are fractionated to separate lighter constituents from higher boiling condensate and cycling said higher boiling condensate to the aforesaid heating Zone.

12. In the conversion of higher boiling hydrocarbon oils into lower boiling ones, the process that comprises passing cycle condensate to a heating zone wherein it is heated to a cracking temperature, combining resultant heated products with oil for cracking in a reaction zone, maintaining cracking conditions of temperature and pressure in the reaction zone, separating resultant cracked products into vapors and residue in a separating zone, withdrawing products comprising residual constituents of cracking from the separating zone and delivering said products to a coking zone wherein conversion to a coke residue takes place, passing the evolved vapors from the coking zone to a primary dephlegmating Zone, passing the dephlegmated vapors from said primary dephlegmating Zone to a secondary dephlegmating zone, separately withdrawing separated vapors from the aforesaid separating `zone and delivering them to said secondary dephlegmating zone, introducing charging stock to said secondary dephlegmating zone to dephlegmate vapors therein, conducting a resultant mixture of reflux condensate and unvaporized charging stock from the secondary dephlegmating zone to the primary dephlegmating zone,`applying only a limited cooling to the primary dephlegmating zone so as to maintain throughout said zonera. temperature Within the cracking range, withdrawing a resultant mixture of reflux condensate and `unvaporized charging stock from .the pri-` mary dephlegmating zone, cycling a portion thereof back to said primary dephlegmating zone to thereby increase the liquid ow therein and prevent coking, utilizing the remaining portion as the oil being combinedwith the lheated prod f ucts from the aforesaid heating zone, subjecting vapors from the secondary dephlegmating zone to JOSEPH MASON BARRON.

Certificate of Correction Patent No. 2 ,343 ,848.

March 7, 1944.

JOSEPH MASON BARRON It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 4, second column, lines 20 to 24, inclusive, the heading of the table should appear as shown below instead of as in Coke only, Run A Coke and dist. fuel oil RunB RunC

and that the said Letters Patent should be reed with this correction therein that the same may conform to the record of the ease in the Patent @Hice Signed and sealed this 23rd dey of Mey, A. D. 1944.

SEAL] LESLIE FRAZER,

Acting Commissioner of Patents.

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