US2166829A - Conversion of hydrocarbon oils - Google Patents

Description

July 18, 1939. K, swAR-rwoop 2,166,829

` 'convEnsIoN oF HYnRocAnon o1Ls Filed Dec'. `11, 1957 Patented July 18, 1939 UNITED STATES PATENT omer.

CONVERSION or HYDRooAnoN OILS Application December 11, 1937, Serial No. 179,288

3 Claims.

This is a combination in part of my co-pending application Serial No. 139,876, filed April 30, 1937.

This invention particularly refers to an improved process for the distillation of hydrocaroperation under independently controlled cracking conditions.

One speciiic embodiment of the invention comprises subjecting reflux condensate iormed within the system, as later described, to cracking temperature at superatmospheric pressure in a heating coil, introducing the heated products into an enlarged reaction chamber, also maintained at superatmospheric pressure, wherein they are subjected to continued cracking and wherefrom vaporous and liquid conversion products are separately withdrawn, introducing said liquid conversion products into a zone of substantially reduced pressure, relative to that employed in the reaction chamber, wherein their appreciable further vapcrization is accomplished, supplyingl said vaporous products separately withdrawn from the reaction chamber to a distilling zone, separate from said reaction 'chamber and from said zone oi substantially reduced pressure, commingling hydrocarbon oil charging stockf for the process with the relatively hot vaporous conversion products thus supplied to said distilling zone, whereby the low-boiling components of the charging stock are vaporized, removing the unvaporized components of the charging stock from said distilling zone, heating the same to cracking temperature at superatmospheric pressure in a separate heating coil, supplying the heated products from said separate heating coil to said reaction chamber, removing vaporous products from said distilling zone, heating the same to an independently controlled relatively high cracking temperature in another separate heating coil and supplying the resulting heated products to said zone of substantially reduced pressure, supplying vaporous products from the latter zone to a fractionator wherein their high-boiling components are condensed as said reflux condensate, condensing the resulting frac- 0 tionated vapors of the desired end-boiling point 55. Referring to the drawing, reflux condensate recovered from within the system and supplied, as will be later described, to heating coil l is heated therein to a desired cracking temperature preferably at a substantially superatmospheric pressure by means of heat supplied by a furnace 2. The resulting hot conversion products are directed from heating coil I through line 3 and valve 4 into reaction chamber 5.

The reaction chamber is also preferably maintained at a substantial superatmospheric pressure and, although not illustrated in the drawing, is preferably insulated Ato conserve heat, whereby the heated products supplied to this Zone are subjected therein to appreciable continued cracklng.

Any of a number of well known alternative arrangements may be provided for supplying heated products to the reaction chamber and separately removing vaporous and liquid products therefrom. In the particular case here illustrated, the heated products from heating coil l are introduced into the upper portion of the chamber and caused to pass downwardly therethrough to its lower portion, from which their vaporous and liquid components are separately removed, the liquid products being directed through line 6 and valve 'l into chamber 8, while the vaporous products are separately withdrawn from a somewhat higher point in the reaction chamber and directed through line 9 and valve i0 to chamber l l.

Chamber 8 is preferably operated at a substantially reduced pressure relative to that employed in the reaction chamber, whereby appreciable further vapcrization of the liquid conversion products supplied to this zone from the reaction chamber is accomplished and, when desired, chamber 8 may be operated as a coking Zone, as will be later described.

When the process is operated for the production of liquid residue in chamber 8, this product may be removed from the lower portion of the chamber and directed through line l2 and valve I3 to cooling and storage or elsewhere as desired.

When the process is operated for the production of coke, to the substantial exclusion of residual liquid, in chamber 8, the coke produced may be allowed to accumulate in this zone and be periodically removed therefrom, preferably after the chamber has been isolated from the rest of the system. A plurality of 'coking chambers may be employed, wheny desired, although only one is illustrated in the drawing, in order that the coking stage, in common with the rest of the system, may be operated continuously by alternately operating, cleaning and preparing the various coking chambers for further operation in any well known manner, not illustrated.

Vapors evolved in chamber 8 from the liquid conversion products supplied thereto from chamber 5, as well as other vaporous products supplied to this zone, as will be later described, are removed from the upper portion of chamber 8 and directed through line I4 and valve I5 to fractionation in fractionator I 6.

Simultaneously with the operation above described, charging stock for the process, which may comprise any desired type of hydrocarbon oil, but is preferably an oil of relatively wide boiling range, is directed from storage or elsewhere through line I9 and valve 2U to pump 2I by means of which it is introduced through line 22 and valve 23 into chamber II. The charging stock thus supplied to chamber Il is `directly commingled in this Zone with the relatively hot vaporous products supplied thereto from chamber 5 and is thereby heated to a suiciently high temperature to effect its appreciable vaporization in this zone. The charging stock is thus separated in chamber I I into low-boiling vaporous fractions and highboiling non-vaporous fractions, the latter being commingled in chamber II with any high-boiling components of the vaporous conversion products supplied to this Zone which are Condensed by contact with the relatively cool charging oil, while the former commingle with the remaining vaporous components of the conversion products. When desired the charging stock may be preheated, by any well known means, not illustrated, prior to its introduction into chamber II. Preferably, however, the temperature to which the charging stock is preheated is substantially below the temperature of the vapors entering chamber II from chamber 5.

The liquid products collected within the lower portion of chamber II are directed therefrom through line 24 and valve 25 to pump 2B by means of which they are supplied through line 2'! and valve 28 to heating coil 29. They are heated in coil 29 to a suitable independently controlled cracking temperature, preferably at a substantial superatmospheric pressure, by means of heat supplied from furnace 33. The resulting heated products are directed from heating coil 29 through line 3I and valve 32 into reaction chamber 5 and, in the particular case here illustrated, are sprayed against the inner surface of the walls of the reaction chamber by means of a suitable spreader or spray arrangement, such as indicated, for example, at 33, whereby their relatively heavy liquid components are directed downward over the walls of the chamber and act as a wash to prevent the excess formation and deposition of coke thereon, while their vaporous components commingle in the reaction chamber with the vaporous components of the heated products supplied to this zone as previously described, from heating coil I, and are subjected therewith to more prolonged cracking time in the reaction chamber than that afforded the heavy liquid products supplied to this zone.

The vaporous components of the material supplied to chamber I I are removed from the upper portion of this zone and directed through line 3S and valve 3l to further conversion in heating coil 38. The vapors thus supplied to heating coil 38 will contain the low-boiling components of the charging stock which are vaporized in chamber I I, as well as the components of the vaporous products supplied from chamber 5 to chamber I I which remain uncondensed in the latter zone.

Preferably, the charging stock contains a sub stantial quantity of such low-boiling components as gasoline r gasoline fractions of poor antiknock value, which will be included in the vaporous stream supplied from chamber I I to heating coil 38.

The vapors supplied to heating coil 38 are therein subjected to conversion conditions regulated to effect the production of high yields of good antiknock gasoline therefrom. The required heat is supplied to the materials passing through heating coil 38 from furnace 54 and preferably a substantial superatmospheric pressure is employed in heating coil 38, although, when desired the pressure employed at the outlet of this zone may be only slightly higher than that employed in chamber 8. The hot conversion products are directed from heating coil 38 through line 55 and are introduced into chamber 8, entering this Zone through valve 56 in line 55 at a point somewhat above that at which liquid products from chamber are supplied thereto or, when desired, they may be introduced into the lower portion of chamber 8 through line E'I and valve 58 to commingle therein with the residual products undergoing distillation and effect their reduction to substantially dry coke.

The vaporous products supplied to fractionator I6, as previously described, are subjected to partial condensation in this zone, whereby their components boiling above the range of the desired nal light distillate product of the process are condensed as reflux condensate. The reflux condensate thus formed in fractionator I 6 is directed from the lower portion of this Zone through line 39 and valve 48 to pump 4I, by means of which it is supplied through line 42 and valve 43 to heating coil I for conversion therein and in the subsequent portions of the system, as previously described.

Fractionated vapors of the desired end-boiling point are withdrawn, together with normally gaseous products of the process, from the upper portion of fractionator I6 and directed through line 44 and valve 45 to condenser 48, the resulting distillate and uncondensed gases pass through line 41 and valve 48 to collection and separation in receiver 49. The uncondensed gases may be released from the receiver through line 50 and valve 5I, while the distillate, comprising the desired low-boiling product of the process, such as, for example, gasoline of good antiknock Value, may be withdrawn from the receiver through line 52 and valve 53 to storage or to any desired further treatment. When desired regulated quantities of the distillate collected in receiver 49 may be recirculated, by well known means not illustrated, to the upper portion of fractionator I5 to serve as a cooling and refluxing medium in this zone.

The preferred range cf operating conditions which may be employed, in an apparatus, such as illustrated and above described, for conducting the process of the invention, may be approxi mately as follows: The first mentioned heating coil, to which reflux condensate from the fractionator of the system is supplied, may employ a conversion temperature measured at the outlet therefrom ranging, for example, from 850 to 1000'J F., preferably with a superatmospheric pressure at this point in the system of from 200 to 800 pounds, or thereabouts, per square inch. The heating coil to which liquid products from the charging stock distilling chamber are supplied may employ any desired conversion temperature ranging from 800 to 900 F., or more, and preferably the pressure employed at the outlet of this zone is substantially the same as that utilized in the reaction chamber to which heated products from said heating coil are supplied, the pressure in the reaction chamber ranging, for example, from to 500 pounds, or more, per square inch, superatmospheric. The vaporous products from the charging stock distiliing chamber are subjected in the heating coil to which they are supplied to an outlet conversion temperature oi the order of 900 to 11.00 F., or thereabouts, and the pressure employed at this point in the system may range from substantially the same employed in the dash distilling or colzing ch ber, to which heated products from this coil are supplied, up to a superatmospheric pressure substantially as high as that employed in the reaction chamber, in which latter case the reaction chamber and the charging stock distilling chamber are preferably operated at substantially the same pressure. The flash distilling or coking chamber is preferably operated at a substantially reduced pressure relative to that employed in the reaction chamber and this reduced pressure may range, for example, from pounds, or the abouts, per square inch, superatmospheric, down to substantially atmospheric pressure. The distilling chamber to which the charging stock is supplied may be operated at substantially the same or lower pressure than that employed in the reaction chamber but is preferably ma' ta red at a sufficient superatmospheric pressu the vaporous products from this Zone thro .gh the heating coil to which they are supplied, into the flash distilling or coking chamber without rie use or" a pump or compressor. The fractionatlng, condensing and collecting portions of the system may be operated at any desired pressure rangfrom substantially the same as that employed in the dash distilling chamber down to substantially atmospheric pressure.

As an example of one specific operation ci the process as it may be conducted in an ap c ratus such as illustrated and above described, ut as charging stock a mixed base crude o 30 A. P. I. gravity, containing some or thereabouts oi 400 end-point gasoline of poor antiknock value; the reflux condensate is subjected in the primary heating coil of the system to a conversion temperature o1 approxi mately 940 F, at a superatmospheric pressure or approximately 300 pounds square inch Th reaction chamber ls maintained at a supera pheric pressure ci approximately 2:0 pounds square inch and liquid products from this zone are supplied to alternately operated coking chambers maintained at a superatmospheric pressure of approximately 75 pounds per inch. Vaporous products are separately removed from the reaction chamber and supplied to a topping chamber wherein they are commingled with the charging stock, the latter zone being operated at a superatmospheric pressure oi approximately 200 pounds per square inch. Liquid products are passed from the topping chamber through a separate heating coil wh- -ein they are quickly heated to an outlet conversion temperature ci approximately 960 Trl. at a superatmospheric pressure of about 250 pounds per square inch and thence introduced into the reaction chamber. The total Vaporous products from the topping chamber are passed through another separate heating coil employing an outlet conversion temperature of approximately 1000 Fland-a'superatmospheric pressure substantially the same as that employed in the topping chamber, the` heated products from the last mentioned heating coil being introduced into direct Contact 4with the residual products undergoinglcoking in ther alternately operated coking chambers, whereby the additional heat thus supplied to the latter serves toeffect their reduction to coke. The .vaporous pro-ducts from the cokingeone' are supplied to the lractionator of the .system -from whichy reflux condensate is returned tothe first mentioned heating coil. The overhead'vaporous'products from the fractionatorare 'condensed and the resulting distillate recovered as -the final gasoline product of the process. This operation will produce, per barrel of charging stock, approximately '70% of 400 F. end-point gasoline having an octane number of 70 or better by the motor method and approximately 40 pounds oi good quality low volatile petroleum coke, the remainder being chargeable principally to uncondensible gas,

I claim as my invention:

1. In a process for the pyrolytic conversion of hydrocarbon oils wherein reux condensate, formed within the system as hereinafter set forth, is cracked at cracking temperature and superatmospheric pressure, resultant vaporous and liquid conversion products separated and the latter appreciably further vaporized in a zone of substantially reduced pressure relative to that at which they are formed, the improvement which comprises commingling hydrocarbon oil charging stock for the process with said vaporous conversion products following separation of the latter from said liquid products and while they are still in heated state, thereby effecting substantial vaporization of the charging stock, heating' the remaining unvaporized components of the charging stock to an independently controlled cracking temperature, commingling the resulting heated products with the heated products of the first mentioned cracking operation, prior to said separation of the latter into vaporous and liquid components, heating the vaporized components of the charging stock and the components of said vaporous conversion products which remain uncondensed by contact with the charging stock to an independently controlled cracking temperature, introducing the heated products of the last mentioned cracking operation into said zone of substantially reduced pressure, removing vaporous products from said zone of substantially reduced pressure, fractionating the same to form said reux condensate which is supplied to the rst mentioned cracking operation, condensing fractionated vapors of the desired end-boiling point, and recovering the resulting distillate.

2. A process for the pyrolytic conversion of hydrocarbon oils which comprises subjecting reflux condensate, formed Within the system, as hereinafter set forth, to conversion conditions of cracking temperature and superatmospheric pressure in a heating coil and communicating enlarged reaction chamber, separately removing resultant vaporous and liquid conversion products from said reaction chamber and appreciably further Vaporizing the latter in a zone of substantially reduced pressure relative to that employed in the reaction chamber, supplying said vaporous conversion products, while still in heated state to a distilling zone and therein commingling the same with hydrocarbon oil charging stock for the process, thereby condensing high-boiling components of said vaporous products and vaporizng the lowboiling components of the charging stock, removing resulting non-vaporous residual liquid from the distilling zone and heating the same to an independently controlled cracking temperature at lsuperatmospheric pressure in a separate heating coil, supplying the heated products from said separate heating coil to said enlarged reaction chamber, separately removing vaporous products from the distilling zone and heating the same to an independently controlled cracking temperature in another separate heating coil, introducing resulting heated products from the last mentioned heating coil into said zone of substantially re-V duced pressure, separating the materials sup- V plied to said zone of substantially reduced pressure into vaporous and non-vaporous components therein, recovering the latter, fractionating said Vaporous components to form said reflux condensate which is supplied to the first mentioned heating coil, condensing fractionated vapors of the desired end-boiling point, and recovering the resulting distillate.

3. A process such as dened in claim 2, wherein hot Vaporous conversion products from the last described cracking operation are contacted in said zone of substantially reduced pressure with the liquid conversion products undergoing vaporization therein and serve to eiect reduction of the latter to substantially dry coke.

KENNETH SWARTWOOD.

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