US2129931A - Conversion of hydrocarbon oils - Google Patents

Description

Sem., is? 19m. J. B, HE@ 2,329,931

CONVERSION OF HYDROCARBON OILS Filed June 27, 193e frac'zozza i011 (bucle/15er Fu rvzace Patented sept. is, rase narra crates au @este 2,129,931 CONVERSHON OIF ROCARBON URLS Application .lune 27, 1936, Serial No. 87,686

9 Claims.

This invention relates to an improved process for the selective conversion of hydrocarbon oils wherein the charging stock and selected high boiling fractions of the intermediate liquid conh version products of the process are subjected to cracking, the resulting vaporous products separated from the residual products, selected low boiling fraction of the intermediate liquid conversion products of the process separately sub- 1U jected to further cracking and subsequently cooled to a temperature below active cracking and polymerization by contact with said residual products, which latter are further vaporized, separating the mixture into vapors and residual 1.-, oils, subjecting the latter to further heating and commingling the additionally heated materials with the vaporous products from the first mentioned cracking step.

It is also within the scope of this invention to 2') either reduce all of the residual products of conversion to relatively dry coke, thus producing high yields of motor fuel having good antiknock qualities or to subject the residual liquids to a viscosity breaking operation to produce a saleable fuel oil.

1.3 This invention is advantageous as applied to the treatment of a wide variety of charging stocks and is particularly well adapted to the treatment of oils of high boiling characteristics Iin that the process provides for either coking all the heavy 30 residual products of the process or for the heat treatmentof the heavy oils in such a manner as to produce a good saleable fuel oil.

In one specific embodiment, the invention comprises subjecting a relatively heavy oil to con- I'I version conditions of cracking temperature and super-atmospheric pressure in a heating coil, subjecting the heated products to additional cracking in a reaction chamber wherein vaporous and residual liquid products are separated and i wherefrom they are separately removed, subjecting the vaporous products to fractionation for the separation of their desired low-boiling fractions from higher boiling reux condensate,

separating the reflux condensate into selected 3 relatively high boiling and low boiling fractions,

returning the high boiling fractions to the heating coil, subjecting the relatively low boiling fractions to independently controlled conversion conditions of cracking temperature and of) super-atmospheric pressure in a separate heating coil, commingling the highly heated conversion products from said separate heating coil with said residual liquid products withdrawn from the reaction chamber, separating the commingled 55 materials into vapors and liquids, subjecting the (Cl. 19e-49) vapors to said fractionation, subjecting the liquid to additional treatment in another separate heating coll, commingling the resulting heated materials with the vaporous productsfrom the rst mentioned conversion step prior to their fraction- 5 ation and recovering from the mixture the final residual product of the process.

The various features and advantages of the invention may be morel clearly shown by reference to the accompanying diagrammatic drawing and the following description thereof. The drawing illustrates only one specific form of an apparatus which may be utilized in carrying out the teachings of the invention and is to be considered only as an illustration.

Referring to the drawing, a charging stock of relatively wide boiling range, such as vcrude petroleum, topped crude or any other hydrocarbon oil, containing a substantial quantity of materials boiling above the range of gasoline may be introduced through line I, valve 2, and pumped by means of pump 3 through line 4 and valve 5, intoI the fractionator 6 wherein any fractionated vapors boiling within range of the desired gasoline product are removed. In case the chargingv stock is an oil of relatively high boiling characteristics and contains no appreciable quantity of material boiling within the gasoline range and no appreciable quantity of material desirable as cracking stock f or the light oil cracking stage of the system, it may, when desired be directed,` all or in part, through line I and valve 8 directly to heating coll 9, located in furnace I0, wherein the oil supplied thereto is heated to the desired cracksuperatmospheric pressure.

The heated products leave coil 9, through line II and valve I2 and enter reaction chamber I3, wherein the vaporous and liquid products are separated. Although any type of reaction chamber may be employed and any other arrangement of inlet and outlet lines may be utilized, in the case here illustrated, the heated products from coil 9 enter the upper portion of reaction chamber 45 I3 and are withdrawn as separate vapor and liquid streams from the lower portion of the reaction chamber,-the vapors passing through line I4 and valve I5, into chamber I6, This allows the heated products, and particularly the vapors, a considerable conversion time in the chamber which is preferably operated at a substantial superatmospheric pressure. Although not shown in the drawing it is also within the scope of. the invention to send. all or a regulated portion of the vaporous products from chamber I3 directly to the fractionator 6.

The residual products are withdrawn from chamber I3 through line Il and valve I8 and introduced by means of pump I9 through line 20 and valve 2I, into line 22 which discharges into chamber 23. When, as is usually the case, chamber 23 is operated at a lower pressure than chamber I3 pump I9 may be eliminated, in which event the residual products from chamber I3 bypass pump I9 through line 24 and valve 25. However, the use of pump I9 permits the use of any desired pressure in chamber 23, irrespective of .the pressure in chamber I3.

Charging 'stock for the process may, when desired, be introduced, all or in part, directly into chamber 23, through line 61 and valve 68, wherein it is subjected to substantial vaporization. When this method of operation is employed the heavy, unvaporized portion of the charging stock is subjected to the same heat treatment as the residual liquid conversion products from chamber 23, which treatment will be later described,

The vaporous products separated from the residual liquid in chamber I6 are withdrawn therefrom through line 26 and valve 27 and directed to fractionator 6, wherein they are separated together with the other materials supplied thereto, into .the desired fractionated vapors, low boiling reflux condensate and high boiling reflux condensate. The fractionated vapors are withdrawn from the fractionator 6 through line 28 and valve 29 to cooling and condensation in condenser 30. The distillate and gases pass from condenser 30 through line 3| and valve 32 to collection and separation in receiver 33. The un- 1 condensed gases are withdrawn from receiver 33 through line 34 and valve 35 and may be utilized in any desired manner. 'I'he naldistillate product of the process which collects in receiver 33,r

the bottom of fractionator 6 through line 38 and valve 39 and is pumped by means of pump 40 through-line 4I and valve 42, to heating coil 9, along with any charging stock supplied directly to the heating coil as previously described.

The relatively low boiling reux condensate is removed as a sidecut from fratlonalmr 6 lthrough line 43 and valve 44 and is pumped by means of pump 45 through line 46 and valve 41, into heat-.

ing coil 48, located in furnace 49, wherein the low boiling reflux condensate is independently heated to the desired cracking temperature preferably at substantial super-atmospheric pressure. from coil 48 through line 50 and valve 5I and commingle in line 22 with the residual liquid from chamber I3. By commingling the residual liquid from chamber I3 with the highly heated conversion products from coil 48, the latter are cooled to a temperature below that at any substantial further cracking thereof but the temperature of the mixture is preferably maintained suiiiciently high to subject the residual liquid from chamber I3 to appreciable further vaporization in chamber 23. This prevents overcracking of the con- The highly heated products are discharged ator 6 wherein they undergo fractionation in the manner previously described. The liquids are withdrawn from the lower portion of chamber 234 through line 54 and valve 55 and are pumped by means of pump 56 through line 5l and valve 58 into ,heating coil 59, located in furnace 60, wherein the liquids are subjected to an additional heat treatment.

Heating coil 59 is designed and Jperated to heat the residual oil in such a manner as to avoid any substantial coke deposition within the heating coil and communicating liner. The residual oil may be subjected to either a viscosity breaking operation in coil 59 or may be heated sufficiently to effect its subsequent reduction to coke. These variable results are accomplished by controlling the temperature and pressure conditions in heating coil 59 and also the time factor and rates of heating in this zone. The additionally heated materials are discharged from heating coil 59 through line 6I and valve 62 into chamber I6.

Depending upon the results desired the time temperature and pressure conditions employed in heating coil 59 may be controlled so that either liquid residuum or substantially dry coke is produced in chamber I6. If it is desirable to produce substantially dry coke in chamber I6 it is preferable to have several points wherein the heated products from coil 59 may enter chamber I6 and for this purpose line 63 and valve 64 are provided. If residual oil is produced in chamber I6 itymay be withdrawn through line 65 and valve 66 to cooling and storage. In the mode of operation wherein coke is produced in chamber I6, line may be utilized both as a drain line and for the introduction of steam or water into the chamber I6 after its operation is completed to facilitate the removal of the coke therefrom. It is within the scope of the invention to employ a plurality of coking chambers similar to I6 although only a single chamber is illustrated in the drawing. In using a plurality of chambers, the chambers preferably are alternately operated, cleaned and prepared for further operation in order to permit continuous coking but two or more chambers may be operated simultaneously, when desired.

In case the vaporous products from chamber I6 contain any appreciable quantity of entrained tarry material, it is within the scope of this invention to provide a suitable knock-out pot, not illustrated, to remove the. tarry material from the vapors prior to their fractionation. It is undesirable to send any pitch-like or tarry materials to the fractionator 6 due to their high coke forming nature when subjected to cracking to the heating coil 9 together with the reflux condensate supplied to this zone from the fractionator.

The preferred range of operating conditions which may be utilized in the apparatus illustrated an-d above described to accomplish the desired results is approximately as follows: The heating coil to which the high-boiling reflux condensate is supplied may utilize an outlet conversion temperature of from 850 to 975 F. preferably with a substantial superatmospheric pressure at this point in the system of from 100 to 500 pounds,

. chamber and the light oil heating coil which may or thereabouts, per square inch. Substantially the same or a somewhat lower superatmospheric pressure may be employed in the communicating reaction chamber and the succeeding chamber to which vaporous products from the reaction chamber and heated residual liquids are supplied preferably employs a substantially reduced pressure which may range from substantially atmospheric to 150 poun-ds, or thereabouts, per square inch. The heating coil to which the low-boiling fractions of the reflux condensate are supplied preferably employs an outlet conversion temperature ranging, for example, from 900 to 1050 F. and a superatmospheric pressure of from 200 to 800 pounds, or more, per square inch. The succeeding chamber to which heated products from the light oil cracking coil and residual liquid from the reaction chamber are supplied preferably employs a substantially reduced pressure relative to the pressures in the reaction range, for example, from substantially atmos-y pheric to 150 pounds, or thereabouts, per square inch, superatmospheric. The heating coil to Which .liquid residue from the last mentioned chamber is supplied may employ a conversion temperature of from 800 to 950 F., preferably with a superatmospheric pressure in this zone of. from to 300 pounds, or thereabouts, per square inch. The fractionating, condensing and collecting portions of the system may utilize pressures substantially the same or somewhat lower than the pressure employedin the communicating chamber utilizing the lowest pressure.

To more specifically illustrate the process of the present invention, as it may be carried out in an apparatus such as illustrated and above described, the following specific example may be considered typical of an operation in which coke is produced as the residual product. g 'I'he heavy charging stock sent to coil 9 is a yKansas topped crude of approximately 24 A.v P. I. gravity and containing no appreciable quantity of material boiling within the gasoline range. The charging stock, together with the heavy reflux condensate from fractionator 6, is heated in coil 9 to a cracking temperature of about 900 F. at a superatmospheric pressure ofy about 350 lbs. per square inch. The resultant highly heated products are subjected to additional conversion time in chamber I3 at a superatmospheric pressure of about 350 lbs. per square inch. The low boiling reflux condensate removed as a sidecut from fractionator 6 is heated in heating coil 48 to a cracking temperature of about 975 F. at a superatmospheric pressure of 500 lbs. per iuareinch. The

highly heated products from coil 48 commingle with the residual products from chamber I3 and the resultant mixture is separated into vapors and liquid in chamber 23 a superatmospheric pressure of about 100 lbs. per square inch. The residual oil from chamber 23 is quickly heated in heating coil 59 in such a manner that no substantial coke deposition occurs in the heating coil, to a temperature -of about 950 F. ata superatmospheric pressure of 150 lbs. per square inch. The additionally heated residual oil from coil 59 is reduced to coke in chamber I6 at a superatmospheric pressure of about 50 lbs. per square inch. Substantially the same pressure is maintained in the succeeding fractionating, condensing and collecting equipment. This operation will produce per barrel of charging stock approximately of 400 F. end-point motor fuel, having an octane rating of about by the motor method and vabout 60' lbs. of low volatile petroleum coke of uniform quality and good structural strength, the remainder being chargeable principally to uncondensible gas and loss.

I claim as my invention:

` 1. In a'process for the conversion of hydrocarbon oils, wherein an oil of relatively high boiling characteristics is subjected to conversion conditions of cracking temperature and superatmospheric pressure in a heating coil and communicating reaction chamber, the resulting liquid and vaporous products separated, the vapors subjected to fractionation for the formation of reflux condensate, fractionated vapors of the desired end boiling point subjected to condensation, the resulting distillate recovered, reux condensate formed by said fractionation separated into selected relatively low boiling and high boiling fractions, the high boiling fractions supplied to the heating coil for further cracking and the low boiling fractions subjected 'to independently controlled conversion conditions of cracking temperature and superatmospheric pressure in a separate heating coil, the improvement which comprises commingling said liquid products separated from the vaporous products of the rst mentioned cracking step and withdrawn from the zone of separation with the heated products from the second mentioned heating coil, separating the resultant mixture into vapors and residual liquid, subjecting the vapors to said fractionation together with the first-named vapors, subjecting the residual liquid to additional heat treatment in aseparate heating coil, introducing the additionally heated materials into another separating zone, supplying vaporous products from the last mentioned separating zone to said'fractionation and recovering residual liquid from the last mentioned separating zone.

ture into vapors and liquid, subjecting the vapors to fractionation, subjecting the liquid to additional heat treatment in a separa-te heating coil to reduce its viscosity, separating the additionailv heated material into vaporous and residual liquid components. withdrawing the latter from the system as a final product suitable as commercial fuel oil. subjecting the vaporous component to fractionation together with the rstnamed vapors. separating the desired fractionated vapors from resultant reflux condensate,

finally condensing the fractionated vapors, sep# oils, which comprises subjecting a selected high boiling intermediate liquid product of the process to conversion conditions of cracking temperature and superatmospheric pressure in a heating coil, separating the resultant vaporous and liquid products, subjecting the latter to additional vaporization, subjecting the remaining liquid to additional heating in a separate heating coil, commingling the additionally heated materials with the vaporous products from the first mentioned conversion step, separating the resultant mixture into vapors and residual liquid, subjecting the vapors to fractionation, separating the fractionated vapors from the resulting reflux condensate, condensing the fractionated vapors and collecting the resultant distillate, separating the reflux condensate formed by said fractionation into selected high boiling and low boiling fractions, returning the high boiling fraction to the rst mentioned heating coil, subjecting the low boiling fraction to independently controlled conversion conditions of cracking temperaturc and superatmospheric pressure in a separate heating coil, contacting the resulting products with the liquid products from the first-mentioned conversion step tov assist the additional vaporization thereof and supplying vapors from this contacting step to the fractionating step.

4. In a process for the conversion of hydrocarbon oils wherein charging stock for the process comprising a relatively high boiling hydrocarbon oil is subjected to conversion conditions of cracking temperature and superatmospheric pressure in a heating coil, the resulting vaporous and liquid conversion products separated, the liquids subjected to additional vaporization, said vaporous product separated by fractionation into vapors of desired end boiling point and reflux condensate, the fractionated vapors cooled and condensed, the resulting distillate recovered as the final desired distillate product of the process, the reflux condensate separated into selected relatively low boiling and high boiling fractions, and the high boiling fractions subjected to said conversion conditions together with the charging stock for the process, the improvement which comprises subjecting said low boiling fractions to independently controlled conversion conditions oi cracking temperature and super-atmospheric pressure in a separate heating coil,- utilizing the resulting highly heated conversion products to provide the necessary heat for said additional vaporization of the residual products from the first mentioned conversion step by commingling the same therewith, separating the resultant vaporous and liquid products and supplying the former to the fractionating step, subjecting the unvaporized portion of the comnngled materials to further heat treatment in a separate heating coil, reducing the residual products from such further heat treatment to relatively dry coke by contact with the heated Vaporous conversion products from the rst mentioned conversion step, and subjecting the vapors from the coking step to said fractionation.

5. In a process for the conversion of hydrocarbon oils wherein a hydrocarbon oil charging stock of relatively wide boiling range is subjected to fractionation in order to recover from the same any components of satisfactory anti-knock value boiling Within the range of gasoline and separate its remaining components into intermediate and heavy fractions, the heavy fraction subjected to conversion conditions of cracking temperature and superatmospheric pressure in a heating coil and the resultant heated products separated into vaporous and liquid components and the latter subjected to additional vaporization to liberate its relatively low boiling fractions and obtain a higher boiling liquid, the improvements which comprises subjecting said higher boiling liquid to additional heat treatment in a separate heating coil wherein the oil is quickly heated to a temperature sufcient to cause coking of its residual fractions in a subsequent coking chamber to which the heated oil is supplied, introducing the hot vaporous products from the first mentioned conversion step into the coking zone to assist the coking operation, removing the vapors from the coking step and supplying them to said fractionation step, subjecting a relatively low boiling intermediate fraction of the vapors obtained by said fractionation together with said intermediate fractions of the charging stock to independently controlled conversion conditions of cracking temperature and superatmospheric pressure in a separate heating coil, contacting the heated products from said separate heating coil with said liquid components of the products from the rst mentioned conversion step whereby to effect said further vaporization thereof, supplying vapors from this contacting step to said fractionating step and finally condensing the fractionated vapors.

6. A process for the conversion of hydrocarbon oils, which comprises subjecting a relatively heavy hydrocarbon oil charging stock to substantial vaporization in a vaporizing Zone, separating the resulting vapors from the residual oil, subjecting the vapors to fractionation for the recovery therefrom of desirable low boiling fractions, a relatively high boiling liquid fraction and a relatively low boiling liquid fraction, subjecting the relatively low boiling fraction to conversion conditions of cracking temperature and super-atmospheric pressure in a heating coil, supplying the resulting heated products to said vaporizing zone to commingle with and effect said vaporization of the charging stock supplied thereto, subjecting the high boiling liquid fraction recovered in the fractionating step to independently controlled conversion conditions of cracking temperature and superatmospheric pressure in a separate heating coil and succeeding reaction chamber, quickly separating the vaporous components of the resulting products from their residual components, supplying the residual components to further vaporization in said vaporizing zone, vremoving the unvaporized residual oil from the vaporizing zone and subjecting it to additional heat treatment in another separate heating coil, introducing the heated material from the last mentioned heating zone and said vaporous components from the reaction chamber into a coking chamber wherein the high boiling components of the resultant mixture are reduced to coke and subjecting the vapors from the coking chamber to said fractionation.

7. In a process for the conversion of hydrocarbon oils wherein a relatively high boiling oil recovered from within the system is subjected to conversion conditions of cracking temperature and superatmospheric pressure in a heating coil and communicating reaction chamber, the resulting vaporous conversion products separated from the liquid products, the liquid products subjected to additional vaporization in a Vaporizing zone, the resulting vapors separated from the residual liquid, fractionating the vapors from the vaporizing zone to recover therefrom the desired low boiling fractions, intermediate liquid fractions and high boiling liquid fractions and the latter supplied to the heating coil for said lconversion the improvement which comprises subjecting the said intermediate liquid fraction to independently controlled conversion conditions of cracking temperature and superatmospheric pressure in a separate heating coil, commingling the highly heated products with the liquid products supplied from the reaction chamber to the vaporizing zone, removing the residual liquid components of the commingled materials from said vaporizing zone, subjecting the same to further heat treatment in another separate heating coil, introducing the additionally heated residual oil into a coking Zone wherein their high boiling componentsare reduced to coke supplying the vaporous products from the reaction chamber to the coking Zone to assist the coking operation, removing the vaporous products from the coking Zone and subjecting them to said fractionation.

8. A conversion process which comprises fractionating hydrocarbon vapors in a fractionating zone to separate a relatively light reflux condensate and a heavier reflux condensate therefrom, heating the heavier condensate to cracking temperature under pressure in a heating coil and then separating the same into vapors and unvaporized oil in a separating chamber, distilling said unvaporized oil in a reduced pressure vaporizing chamber, subjecting said light reux condensate to independently controlled cracking conditions of temperature and pressure ina second heating coil and then introducing the same to said vaporizing chamber to assist the distillation of said unvaporized oil, separately removing vapors and residual oil from the vaporizing chamber and supplying the former to said ractionating Zone, contacting residual oil withdrawn from the vaporizing chamber with the vapors from said separating chamber, supplying the vaporous products of this contacting step to the fractionating zone, and nally condensing the vapors uncondensed in the fractionating zone.

9. The process as dened in claim 8 further characterized in that the residual oil withdrawn from the Vaporizing chamber is independently heated in a third heating coil prior to said contacting step.

JACOB BENJAMIN HEID.

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