US2107793A - Conversion of hydrocarbon oils - Google Patents

Description

Feb. 8, 1938. L c. HUFF CONVERSION OF HYDROCARBON OILS Filed Jan. 19, 1935 INVENTOR LYMAN HUFF A ORNEY good quality;

Patented m. 8, 193a umrsn STATES? PATENT OFFICE 2.1.1.19: Y .couvaas ron or nymwcsaaon ons Lyman 0. Huh, Chicago, Ill., assignor to Universal-il Products Company, Chi .poration of Delaware cago, 111;, a cors u taon January 19, loss, Serial No. use

11 Claims. (01.190-48) This invention particularly refers to an im proved process for the selective conversion of The present" invention is particularly well adapted to the treatment of hydrocarbon oils of relatively wide boiling range such ascrude petro-,- leum, topped crude and the like although it is also advantageous as applied to the treatment of either low-boiling or relatively high-boiling oils.

when employed for the, treatment of oils of relativelywide boiling range, charging stock is preierablyseparated, together with the intermediate conversion products of the process, into selected relatively high-boiling, intermediate and low-boiling fractions. The high-boiling fractions are subjected to conversion conditions of elevated temperature and superatmospheric pressure in a heating coil and ,theresulting heated products are introduced into a coking chamber, preferably operated ata. relativelylow superatmospheric pressure, wherein their high-boiling components are reduced to coke. Vaporousprodnets are withdrawn fromthe coking zone and a any high-boiling.-components, such astars and similar high coke-forming materials, are separatedtherefrom and returned to the coking chamber while the remaining vaporous products are subjected to fractionation. The intermediate fractions of the charging stock and reflux coni densate are subjected to independently controlled conversion conditions of elevated temperature and superatmospheric pressure in .aseparate heating coil and communicating reaction chamher; the resulting vaporous and liquid conversion products separated, the l tter supplied to the coking chamber. wherein ey are reduced'to coke, and the vaporous conversion products are supplied .to said fractionation together with the aforementioned remaining vaporous products from the coking operation. The relatively lowboiling fractions of the charging stock and'reflux condensate are subjected to independently controlled conversion conditions of .elevated temperature and superatmospheric pressure in another separate heating coil, preferably of the type wherein the oil is heated to the desired conversion temperature and then maintained at or near the maximum conversion temperature attained for a predetermined time, and all or a regulated portion of the highly heated products from the last mentioned heating ,coil are introduced into the coking chamber to commingle therein with the materials undergoing coking and supply additional heat thereto to assist their reduction to coke. The intermediate conversion" products of the process separated into said selected relatively low-boiling, intermediate and highboi1ing fractions comprise the reflux condensate formed by said fractionationof the vaporous products of the process and fractionated vapors of. the desired end-boiling. point, are subjected to condensation to form the desired final light distillate product ot'the process, preferably comprising motor fuel of highantiknock value.

- The accompanying diagrammatic drawing illustrates one specific form of apparatus in which the process may be accomplished.

Referring to the drawing, heating coil i is located within a furnace 2, of any suitable form, by means of whichthe oil supplied thereto, in

the manner to be later described, is subjected to the desired conversion conditions of elevated temperature and superatmospheric pressure and the heated products are discharged from the reaction chamber I.

Chamber 5 isalso preferably. maintained at a substantial superatmospheric pressure and, al-

though not indicated in the drawing, is, preferably insulated to minimize the loss of heat therefrom by radiation. Conversion of the heated products from heating coil I, and particularly their vaporous components, continues in the reaction chamber and, in the particular case here -heating coil ,throug-h line 0 and valve 4 into illustrated, the. resulting vaporous and liquid con'version products are separated in this zone.

liquid conversion products may be withdrawn from theilower portion of chamber I through line I and valve I, eitheralone or together with a minor portion of the vaporous conversion products from this zone, and are directed through lines 8 and 8' wntrolled'by the respective valves l and 8' into the respective coking chambers II and II wherein they are reduced to substantially dry coke, aswill be later-more fully de-' scribed. A

vaporous products evolved in coking chambers It and II, as well asany vaporous conversion products supplied, assuch, tothe coking chambers, as will be later more fully described, are

W thd awn irom chambers II and Ill through v 69 further conversion.

the respective lines II and II controlled, respectively, by valves l2 and I2 and are directed through line l3 into separating chamber l4. Vaporous conversion products separately with- 5 drawn from reaction chamber 5 at any desired point in this zone may also be directed through line l5 and valve I6 into separating chamber l4 also at any, desired point.

Chamber I4 is preferably operated at a sub- 10 stantially reduced pressure relative to that employed in the reaction .chamber and the materials supplied to this zone, as previously described, from the coking chambers and, when desired, from the reaction chamber are substantially freed in this zone of any high-boiling components or entrained heavy liquids such as: tars and similar high coke-forming materials unsuitable for further conversion in any of the various heating coils of the system. 'Liquid products removed from the materials supplied to chamber I 4 are withdrawn from the lower portion of this zone through line l1 and valve Hi to pump M9 by means of which they are returned through line 20, valve 2|, line 6 and lines 8 and 8' controlled by the respective valves 9 and 9' to coking chambers l0 and I0, respectively,,for further treatment and reduction to coke. The resulting vapors are withdrawn from the upper portion of chamber l4 through line 22 and valve 23 to fractionation in fractionator 24. The insufliciently converted components of the vaporous products supplied to fractionator 24 are will be presently described in more detail- Frac- 40 tionated vapors of the desired end-boiling point are withdrawn, together with uncondensable gas produced by the process, from the upper portion of fractionator 24 through line 25 and valve 26 and are subjected to condensation and cooling in 45 condenser 21. The resulting distillate and gas passes through-line 28 and valve 29 to collection and separation in receiver 30. Uncondensable gas may be released from the receiver through line 3| and valve 32. Distillate may be with-- drawn from receiver 30 through line 33 and valve 34 to storage or to any desired further treatment.

The selected high-boiling fractions of the reflux condensate formed in fractionator 24, preferably comprising materials such as fuel I oil,

55 heavy gas oil and the like, are. withdrawn from the lower portion of this zone through line 35 and valve 36 to pump 31 by means of which they are directed through line 38 and valve 39 to heating coil 40, wherein they are subjected to The required heat is supplied to the oil passing through heating coil 40 to subject it to the desired conversion conditions of elevated temperatureand superatmospheric pressure by means of a furnace 4| of any suitable 65 form and the heated products are discharged from heating coil 40 through line 42 and valve 43 and are introduced into coking chambers Ill and I0 through the respective lines 44 and {54' controlled respectively by valves 45 and 45.

The selected intermediate fractions of the reflux condensate formed in fractionator 24, [preferably comprising materials such as gas oil and the like may be withdrawn from a suitable intermediate point in this zone, such as, for exam- 7 ple, through line 46 and valve 47, by means 03 which they are supplied to pump 48. The oil thus supplied to pump 48 is directed therefrom through line 49 and valve 50 to conversion in heating coil I, in the manner previously described.

The selectedlow-boiling fractions of the reflux condensate formed in fractionator 24 preferably comprising such materials as pressure distillate .bottoms, kerosene or kerosene distillate and the for further conversion.

Heating coil 56 is located within a furnace 51 of any suitable form and preferably comprises a heating coil of the type wherein the oil supplied thereto is heated to or near the maximum desired conversion temperature and then maintained at a substantially constant temperature approach ing the maximum attained for a predetermined time. The furnace illustrated is of the double end-fired" type which permits independent control of the heating conditions about different portions of the heating coil whereby a heating curve of the desired type may be readily obtained. The

stream of highly heated products is discharged from heating coil 56 through line 58 and valve 59 and may be supplied, in part, through line 62 and valve 63 into separating chamber l4. However, a regulated portion, at least, of the heated products from heating coil 56 is preferably introduced into coking chambers l0 and I0 through lines and 60'respectively, controlled by the respective valves 6| and 6| wherein the highly.

heated products are directly commingled with the materials undergoing coking and supply additional heat thereto for the purpose of assisting their reduction to coke.

Coking chambers l0 and ID are similar zones, preferably operated at a substantially reduced pressure relative to that employed in reaction chamber 5, wherein reduction of the residual liquid conversion products of the process to coke is accomplished. It will be understood, of course, that only one coking chamber or any desired number of such zones may be employed, although two are illustrated in the drawing. Coke may be allowed to accumulate within the coking chamber until it is substantially filled following which it may be cooled, cleaned and prepared for further operation in any well known manner, not illustrated. When a plurality of coking chambers is employed the chambers preferably 'are alternately operated, cleaned and prepared its operation is completed and after it has been I isolated from the rest of the system, in order to hasten cooling and facilitate the-removal of coke therefrom.

Hydrocarbon oil charging stock for the system is supplied, in the case here illustrated, through line 64 and valve 65 to pump 66 by means of which it is fed through line 61.

When the charging stock comprises an oil of relatively wide boiling range which, however, does arcane not contain any appreciable quantity of highboiling materials unsuitable for conversion in heating coil ll it is preferably directed, all or in part, from line 01 through line It and valve .into fractionator 20, wherein it is sublected toportion or all of the charging stock to fractionator it regardless of its characteristics so long i as it does not contain any appreciable quantity of 'materials of a high coke-forming nature unsuitable for conversion in heating coil 40 and does not. contain any appreciable quantity of motor fuel or motorfuel fractions of inferior quality which will contaminate the overhead vaporous terials unsuitable for conversion in heating coil 40 it ispreferably. directed from line 01 through lines II and II, valve l2, line I0 and valve It into vaporieing chamber ll, wherein its high-boiling components remaining unvaporiaed in this sons 1 may commingle with the heavy liquid conversion products supplied from this none, as previously described, to "the coking lone, while any lower boiling vaporous components of the charging may be supplied to chamber it, in the manner described, regardless of its characteristics, serving as a cooling and refluxing medium in this zone and preferably when employed for this purpose it is introduced, as indicated in the drawing, into the upper portion of the chamber and allowed to 3 of the reflux condensate from line ll through line flow downward therethrough.

the charging stock not supplied to the fractionator, as a.cooling and refluxing medium in chamber II. This may be accomplished by diverting regulated quantities of the high-boiling fractions ll, valve 8i and line ll, preferably into the upper portion of chamber ll.

,- It will be understood that the invention is-not limited to the specific form of apparatus illustrated norto the' speciflc process described.

The preferred range of operating conditions which may be employed to accomplish the ob- Jectsof the present invention, in an apparatus of the character illustrated and above described.

may be approximately as.fol1ows: The light oil heating coil to which low-boiling fractions of the reflux condensate are suplied for conversion or I reforming, either alone ortogether with charging stock or low-boilingfractions thereof, preferably employs. an outlet conversion temperature of the order of 950 to 1.100" F., preferably with a superatmospheric pressure measured at this point 'in the system which may range, for example, from 800 to 1,000 pounds, or thereabouts, per square inch. As previously indicated, the ilnal stages of this heating coil preferably comprise the soaking" section wherein the oil previously heated to or near the maximum desired conversion temperature is maintained at a substantially constant temperature, near the maximum, for a predetermined time. The heavy oil heating coll wherein high-boiling fractions of the reflux condensate are subjected to conversion, either alone or together with high-boiling charging stock or highboiling fractions of the charging stock, may employ an outlet conversion temperature ranging, for example, from 800 to 950 l"., preferably with a superatmospheric pressure measured at the outlet from the heating coil of from 100 to 500 pounds, or more, per square inch. The heating coil to which intermediate fractions of the reflux condensate are supplied for conversion, either alone or together with charging stock or charg ing stock fractions of corresp nding characteristics, may employ an outlet conversion temperature of from 900 to-1,000' It, preferably with a superatmospheric pressure at this point in the system of the order of 200 to 800 pounds, or

thereabouts, per square inch. The reaction chamber succeeding the last mentioned heating coil preferably employs a substantial superatmospheric pressure, which may be substantially the,

same or somewhat lower than that employed in the preceding heating coil. The coking chambers are preferably operated at a substantially reduced pressure relative to that employed in the reaction chamber ranging, for example, from, 100 pounds, or thereabouts, per square inch, down to substantially atmospheric pressure. The separating chamber to which vaporous products from the coking chamber are supplied preferably employ's substantially the same or somewhat lower pressure than that utilized in the coking zone. The

'fractionating, condensing and collecting portions of the system may employ pressures substantially the same or somewhat lower than thatemployed in the separating chamber.

As a speciflc example of one of the many possible operations of the process of the present invention as it may be accomplished in an apparatus such as illustrated and above described, the charging stock is an 18, A. P. I. gravity Mid-Continent fuel oil which is supplied, in part, to the fractionatcr and, in part, to the separating chamber preceding the fractionator. High-boiling fractions of the charging stock and of the reflux condensate formed in the fractionator are subiected in the heating coil'to which they are supplied to an outlet temperature of approximately 900' l". at a superatmospheric pressure of about 200 pounds per square inch and the heated products are introduced into alternately operated coking chambersmaintained at a superatmospheric pressure of about 50 pounds per square inch. Intermediate fractions of the charging stock and reflux condensate are subjected in a separate heating coil to an outlet conversion temperature of approximately 950 1",, at a superatmospheric pressure of about 400 pounds per square inch. This pressure is substantially equalized in the succeeding reaction chamber wherein vaporous and liquid conversion products are separated, the latter being supplied direct to the coking chambers while the vaporous products are supplied, together with yaporous products from the coking chamber, to the separating chamber which ,is maintained at a superatmospheric pressure of approximately 40 pounds per square inch. Heavy liquid products recovered in the separating chamberare also returned to the coking chambers and v the vaporous products from the separating chamber are subjected to fractionation for the formation 'of said reflux condensate. The low-boiling fractions of the reflux condensate having a boiling range of approximately 350 to 550 F. are heated in a separate heating coil to a conversion tempera- 800 pounds per square inch. The stream of highly heated products from this zone are introduced into the coking zone and directly commingled therein with the materials undergoing coking. This operation may produce, per barrel of charging stock, approximately 60 percent of 400 F. endpoint motor fuel having an octane number of approximately 70 by the motor method and approximately 100 pounds of low volatile cokeof uniformly good quality and structural strength, the remainder being chargeable, principally, to uncondensable gas.

I claim as my invention:

1. In a process for the conversion of hydrocarbon oils wherein an oil. is subjected to conversion conditions of elevated temperature and superatmospheric pressure in a heating coil, the heated products introduced into an enlarged reaction chamber, also maintained atsuperatmospheric.

pressure, wherein particularly their vaporous components are subjected to appreciable continued conversion and wherein separation of vaporous and liquid conversion products is accomplished, the vaporous and liquid conversion products separately withdrawn from the reaction chamber, the

' heavy reflux condensate from the vaporous products of the process undergoing said fractionation, returning the light reflux condensate to the heating coil for further conversion, subjecting the heavy reflux condensate to independently controlled conversion conditions of elevated temperature and superatmospheric pressure in a separate heating coil, introducing the heated products from said separate heating coil into a coking chamber, withdrawing'liquid conversion. products from the reaction chamber and introducing the same into said coking chamber, supplying vapors from. the coking chamber to a separating chamber wherein undesirable high-boiling components, including any entrained high coke-forming liquids, are removed therefrom, returning the liquid products from said separating chamber to the coking chamcarbon oils wherein an oil is subjected to conversion conditions of elevated temperature and superatmospheric pressure in a heating coil, the

heated products introduced into an enlarged reaction chamber, also maintained at superatmospheric pressure, wherein particularly their vaporous components are subjected to appreciable continued conversion and wherein separation of vaporous and liquid conversion products is accomplished, the vaporous conversion products subjected to-fractionation whereby their insufilciently converted components are condensed as reflux condensate, fractionated vapors of the desired end-boiling point subjected to condensation and the resulting distillate collected, the improvement which comprises separating the reflux condensate formed by said fractionation of the vaporous products of the process into selected relatively low-boiling, intermediate and high boiling fractions, returning intermediate fractions of said reflux condensate to the heating coil for further conversion, subjecting high-boiling fractions of the reflux condensate to independently controlled conversion conditions of elevatedtemperature and superatmospheric pressure in a separate heating coil, introducing the resulting heated products into a coking chamber, withdrawing liquid conversion products from the reaction chamber and introducing the same into the coking chamber, supplying vaporous products from the coking chamber to a separating chamber wherein undesirable high-boiling components, including entrained high coke-forming liquids and the like are removed therefrom, returning said undesirable high-boiling materials to-the coking chamber, subjecting selected low-boiling fractions of said reflux condensate to independently controlled conversion conditions of elevated temperature and superatmospheric pressure in another separate heating coil, introducing regulated portions of the highly heated products from the last mentioned heating coil into the-coking chamber, supplying the remainder of said highly heated products from the last mentioned heating coil to said separating chamber and subjecting vaporous products remaining uncondensed in said separating chamber to said fractionation.

4. A process of the character defined in claim 3 wherein charging stock for the process, comprising hydrocarbon oil of relatively wide boiling range, is separated into selected fractions and wherein fractions of the charging stock corresponding to said selected fractions of the reflux condensate are subjected to conversion therewith.

5. A process of the character defined in claim 3 wherein hydrocarbon oil charging stock for the process is supplied, at least in part, to the fractionating stage of the system.

6. A process of the character defined in claim 3wherein hydrocarbon oil charging stock for the process is supplied, at least in part, to said separating chamber.

"7. The process as defined in claim 3 further characterized in that hydrocarbon oil charging stock for the process is supplied in separate portions to the fractionating stage of the system and to said separating chamber.

8. A hydrocarbon oil conversion process which comprises fractionating hydrocarbon vapors,

formed as hereinafter set forth, to separate relatively heavy, intermediate and light reflux condensates therefrom, heating the heavy reflux condensate to cracking temperature under pressure in a heating coil and then discharging the same into a coking zone, subjecting the intermediate reflux condensate to independently controlled cracking conditions of temperature and pressure in a secondheating coil and separating resultant vapors from unvaporized oil in an enlarged reaction zone, separately removing vapors and unvaporized oil from the reaction zone and introducing the latter to the coking zone, distilling the heated heavy reflux condensate and the unvaporized oil to coke in the coking zone, subjecting the light reflux condensate in a third heating coil to more drastic cracking, than the,

heavy and intermediate reflux condensates, discharging heated products from said third coil into the coking zone to assist the coking operation therein, supplying vapors from the coking zone and from the reaction zone to the fractionating step, and flnally condensing the fractionated vapors. a

9. The process as defined in claim 8 further characterized in that heavy coke-forming components are separated from the vapors from the coking zone prior to the fractionation of these vapors and such separated heavy components returned to the coking zone. l

10. A hydrocarbon oil conversion process which comprises i'ractionating hydrocarbon vapors, formed as hereinafter set forth, to separate relatively heavy, intermediate and light reflux condensates therefrom, heating the heavy reflux condensate to crackin'gtemperature under pressure in a heating coil and then discharging the same into a coking zone, subjecting thedntermediate reflux condensate to independently controlled cracking conditions of temperature and pressure in a second heating coil and separating resultant vapors from unvaporized oil in an enlarged reaction zone, separately removing vapors and unvaporized oil from the reaction zone and introducing the latter to the coking zone, distilling the heated heavy reflux condensate and the unvaporized oil to coke in the coking zone, subjecting the light reflux condensate in a third heating coil to more drastic cracking than the heavy and intermediate reflux condensates, discharging heated products from said third coil into the coking zone to assist the coking operation therein, introducing the vapors from the coking and reaction zones into a contacting zone and therein contacting the same with fresh charging oil for the process, thereby separating heavy components of the vapors and vaporizing the charging oil at least in part, supplying the commingled vapors from the contacting zone to the fr'actionating step, and flnally, condensing the fractionated vapors.

11. The process as deflned in claim 10 further characterized in that liquid products separated in the contacting zone are introduced to the coking zone.

LYMAN C. HUM".

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