US2223192A - Conversion of hydrocarbon oils - Google Patents

Description

Nov. 26, 1940.

K. SWARTWOOD CONVERSION OF HYDROCARBON OILS Original Filed Jan. 19, 1935 INVENTOR KENNETH SWART'WOOD ATTORNEY Patented Nov. 26, 1940 2,223,192 CONVERSION OF HYDROCARBON OILS l Kenneth Swartwood, Chicago, Ill., assignor to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Original application January 19, 1935, Serial No.

2,477. Divided and this application June 30, 1938, Serial No. 216,639 i y l 6 claims. (c1. 19e-s) This is a division of my co-pending application Serial No. 2,477, led January 19, 1935.

This invention particularly refers to an improved process ior the conversion of hydrocarbon oils of relatively wide boiling range (comprising the reflux condensate recovered by fractionation of the final vaporous products of the process) l, followed by separation of the products, together with hydrocarbon oil charging stock for the process, into vaporous and heavy liquid products, each of which are separately subjected to further conversion under definitely controlled more severe conversion conditions than those to which said reflux condensate is subjected and the resulting vaporous products subjected to fractionation for the formation of said reiiux condensate and the recovery of desirable low-boiling liquid products such as motor fuel of high antiknock value.l i Y In one embodiment the invention comprises subjecting oil, comprising intermediate liquid conversion products of the process, to conversion temperature and superatmospheric pressure in a heating coil, introducing the yresulting heated products into a separating chamber to which hydrocarbon oil charging stock for the process is supplied and wherein the charging stock is subjected to appreciable vaporization, separating the vaporous and heavy liquid components of the o comrningled charging stock and conversion products in said separating chamber, withdrawing said heavy liquid from the separating chamber and subjecting the same to a higher conversion temperature at superatmospherie pressure in a separate heating coil without allowing kthe oil to remain in the heating coil for a sufficient length of time to permit any substantial formation and deposition of coke in this zone, introducing the highly heated oil from said separate heat- .o ing coil into a coking chamber wherein it is reduced to substantially dry coke, subjecting vaporous products from said separating chamber, after the removal therefrom of undesirable high-boiling components, including entrained heavy liquids 5 and similar high coke-forming materials, to iurther conversion in another separate heating coil at an appreciable higher conversion temperature than that employed in the i'lrst mentioned heating coil, separating from the resulting products and from the vaporous products from the coking chamber high-boiling polymers and similar residual liquids, subjecting the remaining vapors to fractionation whereby their insuiiiciently converted components are condensed as said intermediate conversion products of the DI'OCeSS,

supplying the latter to the'rst mentioned heating coil for conversion, 'subjecting fractionated vapors of thedesired end-boiling point'to con'- densation and collecting and separating`thel resulting distillate and gas. j L ,35

The accompanying diagrammatic drawing illustrates one spec'iificl form oi apparatus in which the process of the invention may be accomplished.

` Heating coil `l is located within a furnace l2 of any/suitable form by means of which the coil supplied to the heating coil, in the manner to belater more -fully described, is subjected to the desired conversion temperature, preferably at a substantial superatrnosphericA pressure.' The resulting heated products are discharged from the heating :15 coil through line 3 and valve 4 into vaporizing andseparating chamberl 5.' Y 1 I Hydrocarbon oil charging stock for the process, comprising an oil of either relativelylowboiling or high-boiling characteristics oran ,oiloi rela- 20 tively wide boilingrange, may be supplied'through line 6 and valve 1 .to purnpvby means oiwhich it is fed 'throughgline vI lv andvalye I2 into eliamfyber 5 by'well known means; Preferably, however,

a regulated portion orfall' of the charging stock v25 is preheated prior to its introductioninto 1 this zone. 1 This may beaccomplished, for example, by` directing a portionvr or all of the 'charging stoel; through heat exchanger i3, linelll, valve l5,jh'eat 'exchange coil I line' 1j, and' Lvalve' I8 into ,30

chamber.V I le Chamber V5 is a zone oi 'vaporizati'on andfseparation wherein the'chargingstock for the process `is commingled with the hot .,vaporo'us conversion products from heating coil l'vfand wherein the Y3 5' resulting commingledfmaterialsfare,separated intoY yaporous products and .liquidsof relatively high-boiling nature, Chamber 5 may be operated at` any' desired pressure rranging from substantially atmospheric to a superatmospheric` pres- ,40

'sure substantiallythe same as that employed at the outlet from the preceding heating coil. The pressure employed in this zone andthe temperature to'which `the charging stock ris preheated, prior. to its introduction thereto, serve -as con- 45 trols to insure thedesired degreebf vaporiz'ation for the particular charging stock employedand the desired separation of ,vaporous and `liquid conversion products. Fractionating means of any desired type, not illustrated, maybe employed, ,5o

when desired, in the upper portion of chamber to assist in the desired separation of vaporous and liquidl'comp'onents of the commingled charging stock and: conversionproducts inthis Saone. Preferably av suiiicient,superatmospherio pressure p55 stock and, by effecting. partial cooling of ythe vaporous products from chamber 5, also serves as a `means of separating therefrom Vundesirable high-boiling components such as entrained or dissolved heavy liquids and similar high cokeforming materials. The .high-boiling' liquids separated from the vaporous products in heat exchanger I3 may be withdrawn from the lower portion of thiszone through line 24 and valve 25 and may be withdrawn., from ,the system tocooling. and storage or may be disposed of in any other suitable mannen Anot illustrated in the drawing, such. as,l for example. by returning the same to chamber 5 or bysupplying them toheatving coilv 5.1- or to thecoking zone Aor tochamber .29.

YHeating coil23islocated within a. furnace 26 of any suitable .form b-y means of Vwhich vthe vaporous productsvv supplied to'. this zone are heated to thedesired conversion temperature which preferably .is appreciably higher than the .temperature Yemployed in. heating coil I. vThe pressure employedin heating coil 23 .is preferably somewhat less .thanthatemployed in cham- Vber 5 in order tol insure ypassage of the vapors through the .heating .coilwithout the ruse of a pump or compressor, although the useof aY suitable pump or compressor andthe use ,of higher pressure in, heating coil ,23H are entirelywithin -thescope-of theinvention., Y y

The highly heated products are discharged from heating coil 23 through line 21 andvalve 28 into chamber 29 wherein highboiling materials rsuch asheavypolymerization products Aand re- ,siduaijliquid are Aseparatedfrom thev lower boiling .vaporous products.'v

' Heat exchanger-coili, through whicht charg- .ing stock forl thefprocessjmaypass, as previously described, and subjected `therein to preheating,

` ,serves as a "means of partially cooling the vaporous products in this zone to assist theremoval 1 'therefrom .of .said high-,boiling componentsand to retard-or arrest theirfurther conversion.. It

` vis also specifically withinthe scope of. the present invention to effect thedesired degree of cooling 155 in. chamber 29 Vfor the purposeof retarding or i preventing further conversion of the kheated products f-rom.,hea,ting coil 231and for .the purpose .of vassisting the desired separationof vaporousand liquid .products in this zone.by supplying thereto.y a suitablecoolingoil; Provision is 4made,

in .the particular c ase hereillustrated, for supi plying regulated quantities .of' the reflux con,-l

densate from fractionator 36 to theupper portion ,5"of chamber 29through line 30 and. valve 3|.

When desired, fractionating. means of any suitable.form, not illustratedmay 'be employed in the s upper portion ofv chamber 29jto assistthe separation of undesirable high-boiling components from the vaporous products in this'zon'e.'

. It is alsospecically within thei scope of the 'present invention, although not here illustrated,

to cool the stream of hot conversion products from (heating coil 23v suiciently to prevent lany sub- Astantial further conversion thereof, prior to their introduction into chamber'29.v This may be ac- The high-boiling liquids separated from the vaporous conversion products from heating coil 2,3 in chamber 29 may be withdrawn from the lower portion of this zone through line 32 and Valve ,33.and vmay be directed to cooling and storage or may be supplied by well known means not illustrated, to heating coil 51. Vaporous products are withdrawn from the upper portion of chamber 29 through line 34 and valve 35 and are subjected to fractionation in fractionator 36..

The components of thevaporous products supplied to fractionator 36 boiling above the range of the desired final light distillate product of the process are ,condensed in this Zone as reflux condensate, which is withdrawn from the lower .portion of the fractionator through line 31 and valve 38. to pump 39, by means' of which it is supplied through line 40 and valve 4I 'to conversion in heating coil I, in the manner previously described.

Fractionated vaporsy of the desired end-boiling point are directed from thev upper portion of fractionator36 through line 42 and valve 43 and are subjected to condensation and cooling in con- .denser 44. The resulting distillate and uncondensable gas passes through line 45 and valve 46 to collection and separation in receiver 41. Gas may be released from the receiver through line 48 and valve 49. Distillate may be withdrawn from 'outlet temperature fromy the fractionator.

The high-boiling componentsof the charging stock and of the conversion products from heating. coil I, separated lfrom the vaporous components of the commingledmaterials in chamber 5, are withdrawn from the lower portion of this zone through line l542 and valve 53 to pump 54 by means of which .they .are directed Vthrough line 55andva1ve 56 to heatingA coil 51. A furnace 58 of any suitable form supplies the required heat to the relatively heavy oil passing through heating coilj51 to 4subject the same to the desired conversion temperature which, preferably, is appreciably higher than that employed in heating coil I. Although heating coil 51. and furnace 58 are shown in a diagrammatic manner in the drawing, they are preferably of such form that the oil supplied thereto is quickly heated to the desired relatively high i conversion temperature without allowing it to remain in theV heatingcoil and communicating lines fora suiiicient length of time to permit any substantial formation and deposition of coke therein. lThe stream of heated oil is discharged from heating coil 51 throughline 59 and may be directed through one ora plurality of suitable -branch lines 66 `controlled by valves 6| into coking chamber 62 and/or through one or a plurality of similar branch lines 60 controlled by valves 6I' into cokin-g chamber 62', entering either or both of these zones at any desired point or a plurality of points.

Chambers 62 and 62" are similar coking zones wherein the highly heated high-boiling liquids from heating coil 51 are reduced to substantially dry coke. It will be understood that although only two coking chambers are shown in the drawing, one or any desired number of a plurality of these zones may be employed, when desired, and when a plurality is employed the chambers may be operated simultaneously or, preferably, are alternately operated, cleaned and prepared for further operation in order that the coking stage, in common with the rest of the system, may be operated continuously. Chambers 62v and 62 are provided with suitable drain lines 63 and 63', respectively, controlled by the respective valves 64 and 64', which may also serve as a means of introducing steam, water or any other suitable cooling medium into the chamber, after its operation is completed and after it has been lisolated from the rest of the system, in order to hasten cooling and facilitate the removal of coke from the chamber.

Vaporous products are withdrawn from the respective coking chambers 62 and 62 through lines 65 and 65', controlled by the `respective valves 66 and 66', and are directed through line 61 into chamber 29 wherein they commingle with and are subjected to the same treatment afforded the conversion products from heating coil 23.

The preferred range of operating conditions which may be employed to accomplish the purpose of the present invention in an apparatus such as illustrated and above described may be approximately as follows: The heating coil to which the intermediate liquid products yof the process (Reflux condensate) are supplied may utilize a conversion temperature measured at the outlet therefrom, of the order of 800 to 950 F., preferably with a superatmosp-heric pressure at this point in the system of from to 500 pounds, or thereabouts. per square inch. A superatmospheric pressure ranging from substantially the same as that employed in the preceding heating coil down to substantially atmospheric pressure may be utilized in the vaporizing and separating chamber, although a superatmospheric pressure sufficient to effect the passage of the vaporous products in this zone through the succeeding heating coil without the use of a pump or compressor is preferred. The heating coil to which the vaporous products from the first cracking stage of the system are supplied for further conversion may utilize an outlet temperature ranging, for example, from 900 to 1100 F., preferably with substantially atmospheric or a relatively low superatmospheric pressure up to 100 pounds, or thereabouts, per square inch at this point of the system, although higher pressures up to 500 pounds, or more, per square inch may be employed in this zone, when desired, particularly when a high pressure of the same order is employed in the preceding vaporizing and separating chamber. The pressures employed in the separating chamber succeeding the last mentioned heating coil and in the fractionating, condensing and collecting portions of the system may be substantially the same or somewhat lower than the pressure employed in said heating coil. The heating coil of the coking stage of the system vpreferably employs a relatively'high'conversion temperature of the' order o'f900'to110002F. and,

'aspreviously indicated, the'velo'city of the oil andVv rates of heating in thisfzone are sufficiently high to prevent any substantial formation and deposition of coke prior to theintroduction of the heated oil into the coking chamber. The pressure employed in the heating coil of the cokingsystem may range, for example,` from -substant-ially'atmospheric pressure to 200fp'unds, or" mo r`e, per square inch v`superatrnosphe'ric izire'ssurrel and the pressure employed-4in vthis zone may vloe sub- -stantially lequalizedor` reduced in the coking chamber as desired.v 1

liquidvconversion products; comprising a reflux ,.25

condensate from the fractionator of thesystem, are subjected intheheatingfcoil'of the primary cracking stage to a conversion temperature, measured at' thel outletv therefrom, of approximately 930 1F. vat a' superatmospheric pressure of about 250 pounds per square inch, which is reduced in the succeeding vaporizi'ng and separating ychamber to a superatmo'spheric. pressure of about pounds per square inch; ',Ihe heavy liquid productsA from theyaporizing and s'eparatving chamber are quicklyjheated in a separate heating coil to an outlet4 conversion'tempera ture of approximately 980 at a` superatmos- 'pheric pressure of about 1501pounds=per square inch and are introduced into alternately operated coking chambersmaintained ata superatmospheric, pressure of approximately V50 pounds persquare inch. l j

High-boiling components, vvincluding tars and similar high coke-forming liquids,'are ,removedu from the vaporous products fromv the vaporizing' and separating chamber and are returned to the heating coilof the' coking stage'of thesystem. The remaining vaporous vproducts vfrom the vaporizing and separating chamber are subjected in another separate heating coil to an outlet conversion temperature of approximately 1050 F. at a superatmospheric pressure of about 100 pounds per square inch, and are introduced, together with vaporous products from the coking zones, into the succeeding separating chamber. This pressure is reduced in the separating chamber to approximately 30 pounds per square inch superatmospheric pressure which is substantially equalized in the succeeding fractionating, condencing and collecting portions of the system. A regulatedA portion of the final light distillate product of the process is returned to commingle with and cool the stream of hot conversion products from the last mentioned heating coil sufficiently to prevent an appreciable further conversion thereof and a regulated portion of the reuxcondensate from the fractionator of the system is supplied to the upper portion of the separating chamber following the last mentioned heating coil. The charging stock is preheated, prior to its introduction into the vaporizing and separating chamber, to a temperature of approximately '700 F. Residual liquid from the separating chamber preceding the fractionating stage of the system is returned to the coking zone. -Thisoperationmay produce, yper barrel 72 by thel motormethod and approximately 110 ipounds fof petroleum-coke of --good -structural strength and relatively low volatility, the remainder-being chargeable, principally, to uncondensable gas. q Y

vIclaimas my invention: v i

1. A process forthe conversion of hydrocarbon oils 'which comprises, heating reux condensate formed as hereinafter described to crackingV temperature at superatmospheric pressure in a heating coil, introducing resulting heated products into a separating zone, simultaneously supplying hydrocarbon oil .charging stock for the process to saidv separating zone, separating the charging stock and conversion productsin said separating zoneinto vapors and liquid residue, separately removing said .vaporsand liquid residue from the separatingzone,,separating high-boiling componentsfrom the vapors thus removed from the separatinglzone, passing the remainingl vapors through a separate heating coil and therein further .cracking .the same, vseparately heating the liquid residue removed from theseparating zone to coking temperature and distilling the same to coke vin a vcokingzone, supplying vaporous products `evolved from said liquid residue in the .coking zone and .products resulting from the lastnamed cracking operation to another sepa- Vrating zone, therein .separating the commingled `ing temperature prior to its introduction into said separating zone by passing rthe charging Stock in indirectheat exchange Iwith vthe :relatively hot vaporsremoved from the .rst named ,separatinglzone y3. A-.processsuch dened inl claim 1,. wherein saidliquid residue subjected to coking is passed through .another separate heatingfcoil, .therein fquickly heated to a high cracking temperature A`under non-coking conditions and vthe resulting to its introduction to therst-named separating zoneyis passedin indirect heat lexchange relation vWith the commingled `vapors in the secondmentioned separating zone.

5. The process as defined in claim 1 further characterized in that the charging stock, prior to its introduction to the first-named separating zone, is passed iny indirect heat exchange relation With the commingled vapors in the secondmentioned separating zone and With the yvapors from Whichsaid high-boiling components arefbe ing separated.

6. A hydrocarbon'oil conversion process Which comprises subjecting a relativelyv clean reiiux condensate to cracking conditions in a heating coil and introducing the resultant products into a separating chamber, also introducing charging oil for the process to'said chamber, separating the commingled materials into vapors andresidual oil `in the chamber, lremoving vapors from the chamber and subjecting the same to vapor phase cracking conditions in a-second heating coil, separately removing residual oil ,from the chamber` and reducing the same to-coke in a coking chamber, introducing the yaporous yproducts from thefcoking chamber and from said second coil into an independent separating chamber-and therein separating high-boiling components of the commingled vapors, fractionating the remaining uncondensed vapors from said independent chamber to condense heavier fractions thereof, supplying fractions so condensed to the first-mentionedheating Acoil assaid reflux condensate, and nally condensing the fractionated vapors, the process being further characterized in that the charging oil, prior to its introduction to the rst-mentioned chamber, is passed in indirect heat exchange relation with the commingled vapors in said independent chamber to preheat the charging oiland assist the separation of said high-boiling components.

KENNETH SWARTWOOD.

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