US1940673A - Conversion of hydrocarbon oils - Google Patents

Description

Dec. 26, 1933. c.H. ANGELL coNvERsIoN oF HYDRooARBoN oILs Fiied Feb. 1, 1952 mN mmmZmn-ZOU ATTORNE atented Dec. 26, 1933 ,PATENT OFFICE 1,940,673 CONVERSION or IIYDROOARBON oILs y Charles H. Angell, Chicago, Ill., assignor to Universal Oil Products Company, Chicago, Ill., a corporation of South Dakota Application Februaryl, 1932. Serial No. 590,025

'6 Claims.

This invention relates to the conversion of hydrocarbon oils andmoreparticularly refers to an improved process and apparatus for the production; from hydrocarbon oil, of motor fuel of high antiknock value and substantially dry carbonaceous residue.

The present invention embraces the conversion of a hydrocarbon oil and separation of vaporous and liquid conversion products followed by con- 0 tinued conversion of the vapors, coking of the residual liquid and segregation of the intermediate products resulting from said continued conversion of the vapors into fractions of different boiling ranges each of which are simultaneously subjected to independently controlled conversion conditions best suited for the production therefrom of maximum yields of motor fuel of high` antiknock value. 1

The invention contemplates the use of any type of charging stock ranging from light distillates such as straight-run gasoline, naphtha or the like through the entirerange of petroleum products down to heavy residual Oils and speciiically includes the various grades of crude oil. When relatively light charging stock is employed it is preferably subjected to conversion together with the relatively light intermediate conversion products, of the system and, conversely, when a relatively heavy charging stock is utilized it is preferably-subjected to conversion together with the relatively heavy intermediate conversion products of the system. When the charging stock contains substantial quantities of both relatively light and relatively heavy fractions, the invention specifically provides for its separation into relatively light and relatively heavy fractions which are selectively commingled with the relatively light and relatively heavy intermediate conversion products and subjected therewith to the conditions of .the process best suited for their conversion into maximum yields of desirablelight products.

In one of its more specific embodiments the Y invention contemplates subjecting relatively heavy intermediate products resulting from the pyrolytic conversion of oil to relatively mild conversion conditions in a heating element, simultaneously subjecting relatively light intermediate conversion products of the same process to more severe conversion conditions in a separate heating element, roughly separating vaporous and residual liquid conversion products from both heating elements, subjecting the vapors to continued conversion in another separate heating element and thence directly contacting them with said residual liquid conversion products in a low pressure coking` zone for the purpose of reducing the latter to substantially devolatilizcd coke, subjecting vapors from the coking zone to fractionation, uncondensed vapors from which are subjected to condensation and cooling followed by co1- lection of the resulting desirable light distillate and gas, supplying raw oil charging stock for the system to said fractionating zone whereby it is separated into fractions roughly corresponding to said relatively light and relatively heavy intermediate conversion products also separated in vsaid fractionating zone and subjecting said fractions of the charging stock to conversion with said corresponding fractions of the intermediate conversion products.

A drawing is attached which diagrammatically illustrates cracking equipment of conventional form arranged to permit operations in accordance with the principles of the present invention. Ap- 76 paratus of modied form may be employed Without departing from the principles of the invention and yoperating conditions may be varied to suit requirements.

` The description of the drawing, which follows, includes a description of the procso ess of the invention as it may be practiced in the l specific form of apparatus illustrated.

Raw oil charging stock may s be supplied through line l and valve 2 to pump 3 from which it is fed through line 4, valve 5, line 50, valve 5l a5 and' line 5'7 to heating element 7. This heating element is located in a furnace 8 of any suitable form and the oil supplied thereto is heated preferably to a relatively mild conversion temperature at substantial superatmospheric pressure. The heated `materials are discharge from heating element 7 through line 9 and valve l0 into separator l1.

Separator 11 is a zone of rough separation preferably maintained at substantial superata5 mospheric pressure wherein residual liquid and vaporous conversion products may separatewithout substantial further conversion. Residual' liquidfrom separator 1l is discharged through line 21 and valve 22 into reduced pressure cok- 100 ing chamber( 23. Vaporous products are discharged from the separator through line 12 and valve 13 to pump or compressor 14 from which they are supplied through line 15 and valve 16 to heating element l'I-which is located in a fur- 105 nace 18 of any suitable form wherein they are subjected to continued conversion at substantially the same or at a higher temperature than thatI employed in separator l1A and preferably at a substantial superatmcspheric pressure. Heated through line 19 and valve 20 into coking chamber 23. In many cases it ,will be satisfactory to operate heating element 17 at substantially the same or slightly lower pressure than that employed in separator 11, in which case pump 14 may be dispensed with by use of suitable and well known by-pass means, not illustrated. y Coking chamber 23 is preferably maintained at substantially atmospheric or relatively low superatmospheric pressure and the residual oil introduced into this zone from separator 11 is directly contacted with the relatively hot vaporous products from'heating element 17. Preferably counter-current contact is established between these two materials in chamber 23, residual liquid being introduced into the upperA portion thereof and passing downward through the chamber while the heated vapors are introduced into the lower .portion of the chamber, passing upward therethrough to-be withdrawn, together with volatile portions of the residual oil liberated by the heat carrying vapors and by the pressure reductionin the coking chamber, while substantially devolatilized coke accumulates within the chamber to be removed .after its operation is discontinued. It will be understood that a plurality of coking chambers similar to chamber 23 may be employed although only one is illustrated in the drawing, in which case they may be operated simultaneously or, preferably, are alternately operated, to permit a prolonged operating cycle.

Vapors from chamber 23 pass through line 24 and valve 25 to fractionation in fractionator 26 wherein they are separated into various coin-J ponents comprising relatively heavy intermediate conversion products which are condensed as reflux condensate and collect within the lower portion of the fractionator, relatively light intermediate conversion products which are condensed within the upper portion of the fractionator and withdrawn as a side stream therefrom. and desirable light end-products which are withdrawn, in vaporous state, from the'upper portion of the fractionator, through line, 27 and valve 28, subjected to condensation amil cooling in condenser 29, distillate and uncondensable gas from which passes through line 30 and valve 31 to be collected in receiver 3-2. Uncondensable gas may be released from the receiver through line 33 and valve 34. Distillate may be withdrawn ,from this zone through line 35 and valve 36.

The relatively heavy intermediate conversion products which collect as reux condensate in the lower portion of fractionator 26 are withdrawnv therefrom `through line 54 and valve 55 to pump 56 from which they are fed through line 57 and valve 58 to heating element 7 for further conversion.

Relatively light intermediate conversion products are withdrawn as a side stream from fractionator 26 through line 40 and valve 41 to pump 42 from which they are fed through line 43, valve 44 and lire 45 to heating element 46. Heating element 46A is located in ani7 suitable form of furnace 47 and the oil supplied to this zone, is heated preferably to a higher conversion temperature' than that employed in heating element 7 at substantidal'fsuperatmospheric pressure and is discharged through line 48 and valve 49 into separatorv 11 to c\ mmingle therein with the heated materials from heating element 7 to be subjected therewith to the further treatment previously described. 4

` A1,940,673 materials from heating element 17 are discharged Y When desired, particularly in case the charging stock is a relatively light oil corresponding more nearly in boiling range and in cracking characteristics to Lthe relatively light interme- `diate conversion prducts thany to the relatively heavy intermediate conversion products, all or any portion of the Vraw oil may be directed through valve 6 in line 4'into line 45, commingling therein with the side stream from fractionator 26 and passing therewith to heating element 46 for further conversion. Also, when desired, and particularly when the charging stock contains substantial quantities of components corresponding to both the relatively light and relatively heavy intermediate conversion products separated in fractionator 26 and contains no appreciable amount of materials, such as poor antiknock motor fuel, which will contaminate the iinal light product of the system, all or any portion of the charging stock may be diverted from line 4 through line 52 and valve 53 into fractionator 26 wherein it is substantially vaporized and fractionated, its lighter components collecting with the relatively light intermediate conversion products and its heavier components collecting with the relatively heavy intermediate conversion products. In this manner the light and heavy components of the charging stock are separated and each is subjected to the conversion conditions of the process most suitable for the production therefrom of maximum yields of the desired products. When the charging stock is a crude or other oil containing poor antilrnock motor fuel and also containing substantial quantities of relatively heavy components it is preferably supplied to heating element 7 in the manner rst described. On the other hand when the charging stock comprises or contains appreciable quantities of poor antiknock motor fuel but does not contain substantial amounts of relatively heavy materials corresponding to the relativelyvheavy intermediate conversion products of the system, it is preferably supplied to heating element 46, together with the relatively light intermediate conversion products. Y

The heating element to which the relatively heavy intermediate conversion products are supplied preferably utilizes 'temperatures of the order of 800 to 950 F. and substantial superatmospheric pressures of the order of to 500 pounds, or more, per square inch. The heating element to which the relatively light intermediate conversion products are supplied preferably employs more severe conversion conditions with temperatures of the order of 900 to1050 F. and substantial superatmospheric pressures ranging from 100 to 500 pounds or more per square inch. The nature of the conversion conditions to which vaporous products from the separatingzone are subjected may be substantially the same or more severe than .those obtaining in the separator; temperatures in this heating element ranging, for example, from 9.00 to 1200 F. with pressures which may range from substantially atmospheric to superatmospheric pressures of the order of 800 separating chamber.` The separator is maintained-ata pressure of about 300'pounds per square inch. Residual liquid from this zone is discharged into alternately operated colsing chambers maintained under a pressure oi approximately 100 `pounds per square inch. lapors 0 from the separator are subjected to a temperature of approximately 950 F. under a 'superatmospheric pressure of approximately 500 pounds per square inch and are thence introduced into the alternately operated colring chambers below the level of residual liquid. This operation may yield approximately 72 percent of motor fuel having an antilmoclr value equivalent to an octane numberof approximately 85. In addition there maybe produced, per barrel of charging Stoch, o approximately o'pounds of colte having a volatile content of less than l2 percent and about 000 cubic feet of uncondensable gas.

as an example oi another operation, utilizing as charging stock a Texas crude oil oi about 22 A. F. I. gravity having an initial boiling point ci? about 407 F. and containing approximately 55 percent oi material boiling up to 600 F.; the crude is supplied to the irantionator `oli the system where its components boiling above and below approximately 600 F. are separated. The

heavy portion of the crude, .together with the heavy intermediate conversion products, is subjected to a temperature oi approximately 090 under a superatmospheric pressure of approxicomprisingthe relatively light components oi the crude and relatively light intermediate conversion products and boiling between' appoximately @00 and 000 F. are separately subjected to a temperature of about 920 F. under a superatmospheric pressure of approximately 350 pounds per square inch. Vapors from the separating zone are subjected to continued conversion at a temperature ci approximately 925 F. under approximately 350 l 5 pounds pressure pery square inch.

The colring chamber and the succeeding fractionating, oondensing and collecting portions of the system are n `n'ia'intained 'at substantially atmospheric pressure. This operation may yield, per barrel of charging stock, `approximately 'l0 percent of motor fuel having an octane number of approxi-- mately and in addition about 80 pounds of low volatile coke and about 600 cubic feet of uncondensable gas may be produced.

As an @example of another operation util as charging stock a Montana. crude oil ofabout 51 A. P. I. gravity having an-initial boiling point of approximately 180 F. containing approximately 65 percent of material boiling up to `410 F. and approximately percent at 585 F. The total charging stock is supplied to the same heating element as that to which relatively light intermediate conversion products boiling between approximately 400 and 600 F. are'supplied. The

75 commingled crude and relatively light intermedimately 350' pounds per `square inch. lldaterialsV ate conversion products are subjected to a temc perature of approximately 950 F. under a superatmospheric pressure of about 500 pounds per square inch. Relatively'heavy intermediate conversion products are separately subjected to a temperature of approximately 875 F. under a superatmospheric pressure of about 500 pounds per square inch. Vapors from the separating zone are subjected to continued conversion at approximately 950 F. and 500 pounds pressure. 'llhe cohing zone is maintained at a pressure oi approximately pounds per square inch. This operation may yield approximately 87 percent of motor fuel and approximately 000 cubicxfeet of gas per barrel oi charging stock. A relatively small percentage oi colse is deposited in the coking chamber. The antilrnockvalue of the motor fuel product is equivalent to an octane number of approximately t5 as compared with an octane rating on that portion of the crude boiling up to approximately li00 F. oi less than 35. f

While the foregoing examples are intended to typiiy three types or operation which may be utilized in accordance vvith the principles of the present invention, it will be understood that other types oi charging stool; and diversified operating conditions too numerous to be here described in y detail, may be employed without departing from the scope oi the invention.

l claim as my invention:

lia process for cracking hydrocarbon oil to produce therefrom low boiling distillate and colte `which comprises subjecting;A the oil to conversion temperature at super-atmpspheric presvsure in a heating zone, introducing the heated matenlal into. a separator wherein vapors and non-vaporous residue are separated, introducing the residue into a colring chamber, subjecting vapors from the separator to continue conversion in a separate heating coil, introducing the heated vapors into the colring chamber tot lll@ llt

whereby to colte said residue by direct contact with the heated vapors, subjecting vaporous prodnets from the colring chamber to fractionation,- removing overhead vaporous products from the iractionator, subjecting them to condensation and collecting the resulting distillate and gas, removing a relatively heavy portionfoi? the rethereirom and subjecting it to conversion, to-

ing arelatively light portion ofthe reflux conheating coil andyintroducing the heated materials into said separator.

2. A process for cracking hydrocarbon oil to 4ux condensate vcondensed. in the iractionator i gether with the raw oil charging stoclr, removidensatescondensed in the fractionator therefrom, subjecting it to further conversion in a third produce therefrom'lovv boiling distillate and coke which comprises. subjecting the oil to conversion temperature at super-atmospheric pressure in a heating zone, introducing the heated material into a separator wherein vapors and non-vaporous residue are separated, introducing the residue into a coking chamber, subjecting vapors fromfthe separator to continued conversion in a separate heating coil, introducing the heated vapors into the colring chamber whereby to coke said residue by direct contact with the heated vapors, subjecting vaporous products from the coking chamber to fractionation, removing overhead vaporous products from the fractionator, subjecting them to condensation and collecting the resulting distillate and gas, removing a relatively light portion of the redux condensate condensed in the fractionator therefrom and subtor of the system wherein it commingles with the* vaporous conversion products and is separated,

together with the intermediate conversion products condensed in the fractionator, into a relatively light and a relatively heavy fraction, subjecting each of said fractions to independently controlled conversion conditions in separate heating elements and introducing heated materials from both heating elements into a separator wherein vapors and nonvaporous residue are separated, introducing the nonvaporous residue into a coking chamber, removing vapors from the separator and subjecting them to continued conversion in another separate heating element, introducing the heated vapors into the coking chamber whereby the residue is reduced to coke by direct contact with the heated vapors, directing vapors from thev coking chamber to the fractionator wherein 'their insuiiciently converted components condensed by yfractionation are separated into light and heavy fractions, as already described, removing an overhead vaporous product from the fractionator, subjecting it to condensation and collecting the resulting products.

4. A cracking process which comprises heating hydrocarbon oil to cracking temperature in a flrstheating zone and separating vapors from unvaporized oil in a separating zone, subjecting the separated vapors to vapor phase inversion in a second heating zone, Vdistilling the unvaporized oil in contact with resultant hot vapors in a distilling"zone, removing vapors from the distilling zone and dephlegmating the same to condense heavier fractions thereof, passing at least a portion of the resultant reiiux condensate through a third heating zone and subjecting the same therein to independently controlled cracking conditions of temperature and pressure, introducing the thus heated reflux condensate into the separating zone, and nally con--A densing the dephlegmated vapors. 5. The process as defined in claim 4 further characterized in that relatively light and hea'vy reflux condensates are formed by the dephlegmation, the heavier reilux being supplied to said first heating zone and the lighter reiiuxPbeing` supplied to said third heatingzone.

6. A cracking process whichl comprises heating hydrocarbon oil to cracking temperature in a rst heating zone and separating vapors from unvaporized oil in a separating zone, subjecting the separated vapors to vapor-phase conversion through a third heating zone maintained, at

higher cracking temperature than said rst heating zone, discharging the thus heated` cut into the separating zone, and finally condensing the vapors uncondensed in2 the dephlegmatingzone.

CHARLES H. ANGELL.

Images