US2132639A - Treatment of hydrocarbon oils - Google Patents

Description

"Oct.' 11', 1938.

J. c. MORRELL. f 2,132,639v

TREATMENT OF HYDROCARBON OI`LS Filed Aug. l0, 1936v PgatentednOct. lll, 1938 TREATMENT oF nynnocaanou oms Jacque C. Morrell,` Chicago; Ill., assigner to Uni-.1" l versal Oil Products'Cornpany, Chicago, lll., a

corporation oi Delawa (Applicacxdnaumclo, 193s,E semi No, 95,166` o s (ci: 13s-4s) This is a continuation*-in-part of mycopending application Serial #524,430, filed March 23, 1931.

,f Theinvention relates to animproved kprocess 5 for thecracking of hydrocarbon oils ofrelatively high-boiling characteristics to produce substan the process.

15 The process employs two charging stockjm of which comprises hydrocarbon oil oi'high-boiling characteristics or, of relativelyv wide,

the relative quantities of the two.

The process," is preferably conducted, in a the 1owervporuon ofthe L5 the coking chamber. Separate heating coils are employed for independently heating the primary and secondary charging stocks each to the' desired temperature'. preferably at a, V.substantial pass downwardly through this `zone andare subcontinued cracking therein,

;` Jected to appreciable prior to their discharge from the lower portion thereof. The secondary charging stock is heated to a substantially higher cracking temperature K or,-ln part, toeach'ot these zones. Y r`When highly heated products from the, secondary charging stock heating coil are supplied crease the temperature *andrete of cracking'in tion,

ber :without encountering theexcessive formation anddeposition of `coke in the heating coil(y 'I'he vaporous. components yare thereby subjected, in the reaction chamber,

tionand deposition of coke inthis me and the communicating lines,` while the q vtity supt .plied to the coking chamber is' suiiicient torethis zone to coke duce .the residual products in of the desired low volatility.

- substantial forma-l` the reaction chamben- In this method otoper'ay so A"mi

l process for the Vaporous products are directed from the coking zone to a fractionator wherein their components boiling above the range of the desired gasoline product of the process are condensed as reflux condensate. The vaporous products resulting from such fractionation, preferably comprising gasoline of the desired end boiling point and of good antiknock value, are subjected to condensation and the resulting distillate recovered. y

The reflux condensate formed by said fractionation is, of course, the result of cracking the' two virgin charging stocks and I have found that this reflux condensatecontains a substantial amount, at least, of oils which, although of higher boiling characteristics than the secondary charging stock, may be further cracked to vbetter advantage under the relatively severe cracking conditions employed in the secondary charging stock heating coil than under the ymilder cracking conditions employed for the higher boiling primary virgin charging stock. There fore, in the present process, such components of the reflux condensate as are suitable for cracking, together with the secondary charging stock, are segregated in the fractionatingstep from its .higher boiling components .and supplied for additional cracking heating coil.

I have further found that the relatively highboiling fractions yof the .reflux condensate, comprising' its components remaining after the separation therefrom of the fractions supplied to the rseco'ndarycharging stock heating coil, are ordinarily suitable for further cracking under the conditions employed for the primary charging stock, even though they are of higher boiling characteristics or contain a substantial quantity -ofmateri'als of higher boiling characteristics than the primary charging stock. Such materials are, therefore, in the present process, returned to the primary charging stock heating coil for further cracking.

It will be apparent from the foregoing description of the operation,

to the secondary charging stock selective simultaneous cracking of both light and heavy oils and the Areforming coke as the residual of gasoline to produce high yields of gasoline of good antiknock value and minor yields of gas and good quality coke.

I am fully aware that various steps and features of the process such as the reforming of gasoline, the use of a high-pressure reaction chamber and reduced pressure vaporizing chamber connected in series and the production of product of the process are not in themselves new in the art but the improved process of this invention depends upon the cooperative relation of the various steps and features of the process which cooperate in a new and advantageous manner to produce the desired final results.

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

`Referring to the drawing. primary charging stock of the n ature previously indicated issupplied through line I and valve 2 to pump 3 by means of which it is fed through line 4 and valve 5 to heating coil 6. The oil is heated in this zone to the desired cracking temperature, preferably at a superatrnospheric pressure, by means of heat supplied from furnace 1. The heated products are discharged from heating coil 5 through in this zone that it provides a-unifiedI line 8 and valve l preferably into the upper portion of reaction chamber I0.

Chamber I'II is also preferably maintained at a substantial superatmospheric pressure and, al-

though not indcate inthev drawing, this zone is preferably insulated to conserve heat. The heated products supplied to chamber I pass downwardly through substantially the entire length of this zone and, in the particular case here illustrated, both vaporous and liquid products are withdrawn in commingled state Vfrom the lower portion of the reaction chamber and are directed through line II and valve I2 into chamber I3.

It is also within the scope of the invention, although not illustrated in the drawing, to separately remove vaporous and liquid conversion products from the lower portion of chamber I0 and to introduce both of these materials into chamber vI3 at the same or at separate points or, when desired, to supply a regulated portion or all of the vaporous products separately withdrawn from chamber IIs directly 4to fractionator I8 instead of to chamber I3. However, in accordance with the preferred method of operation, the total vaporous and liquid conversion products from chamber II! are supplied to chamber I3 either as a single stream or as separate'streams.

In chamber I3 the heavy residual liquid components separate from thevaporous components of the materials supplied to this zone and are reduced to substantially dry coke, the coking operation being vaccomplished either with or without the assistance of other highly heated conversion products supplied to this zone, as will be later described, and in either case being assisted by the reduced pressure employed in chamber I3 relative to that utilized in chamber I0.

It is, of course, also wit-hin the scope of the invention, when desired, to employtwo or more' coking' chambers, although only one is illustrated in the drawing, and when a plurality of coking chambers is employed they preferably are a1- ternately operated, cleaned and prepared for further operation in 'orderthat the coking stage, in common with the rest of the system, may be operated continuously. Coke produced is allowed to accumulatein the coking chamber or chambers in operation and may be removed therefrom in any well known manner, not illustrated, after the coking zone is substantially filled or after its operationv has been completed for any other reason.

f Chamber I3 is provided with a drain-line Il and valve I5 and this line may ralso serve, when desired, as a means of introducing steam, water or other suitable cooling material into the chamber, after its operation has been completed and preferably after it has been isolated from the rest of the system, ln order to hasten cooling and facilitate removal of the coke therefrom.

Vaporous products are withdrawn from the upper portion of the coking chamber and directed through line I6 and valve I1into fractionator I8, wherein their components boiling above the range of the desired final light distillate product of the process are condensed as reflux condensate.

Fractionated vapors of the desired end-boiling point, consisting preferably of good antiknock gasoline and gaseousprodu'cts of the process, are directed from the upper portion of the fractionator through line I9 and valve 20 to cooling and condensation in condenser 2l. The resulting distillate and uncondensed gases are directed i5 fractionator and sisting fractionation -ofthevaporsfand to main-v tain the desired vaporjoutlet temperature therefrom. c I o v it isfed through'line 44, Vvalve 45 and line 33 to` heating coil 40. n 'o The oil passing through heating coil 40 is main# tained at the desired cracking temperature and preferablyV at a substantial vsuperatm.)spheric pressure lfor a predetermined time,v the tempera ture, pressure and time Yconditions employed in this zone being regulated to materially` improve the antiknock value of the poor quality gasoline or gasoline fractions supplied thereto and toconvert the higher boiling oils supplied to this. 4zone into substantial yields of'good quality gasoline.

Heatedproducts arey discharged from heating coil 4U through line the upper portion of this zone through valve 48 vzone through linef49 and valve rected, in part, into both the upper and lower portions of the coking chamber.

All or a regulatedportio'n of the highly heated y products from heating coil 48 may, when desired, be directed' from 'line 4I` through line 5I and valve 52', preferably into the upper portion of re- ,action `chamber I and in the preferred method of operation a regulated portion of the heated products from coil 40 is thus supplied to reaction chamber'l, `while the remaining portion is introducedinto the coking,chamber."=`

A `The reflux into selected relatively low-j-boiling fractions best suited for further cracking' in heating coil 48 and thehigher boiling fractions which may be cracked to better advantage in heating coil 6.

'I'he 4high-boiling fractions of the reflux condensateare directed fromi the lower portion of fractionator I8 through line 29 and valve 30 to pump 3 I, by means of which they are fed through line 32 and valve 33 into line 4 and thence to heating coil 6.

The relatively low-boiling fractions of the `reflux condensate,which preferably constitute a major portion of the total reflux formed in the fractionating step, are withdrawn from one or a plurality of suitableintermediate points in the directed through line 34 and valve 35 to pump'36 wherefrom they are fed through line 31 and valve 38 into line 38 and thence to heating coil 40, together with the secondary charging stock.

It will be noted, in connection with the drawing and the above description thereof, that the `reflux condensate formed in fractionator I8 contains no oil which has not been previously subjected tocracking. Such oils, and particularly 5 those resulting from the cracking of virgin charg- Simultaneous with the operation above 'described, secondary charging stock of the errar;v acter previously mentioned' is supplied through' line 4I' and valve`42 to pump 43 by means of which" i 41 and may be directed, all or in part, into cokingchamber I3, entering either inline 41 or entering the lowerportion of thiskr `SII or being difcondensate formed in fractionator `I8 is` preferably separated, as here illustrated,

ing stock, ordinarily require theuse of` more severe'cracking condltionslto produce the .maxif mum yields of good quality gasoline than `a virgin oilof similarboiling characteristics. k The lowboiling fractions of the refluxcondensate supplied to heating coil 484preferably are substantially'devoid of materials 'boilingL within the range ofthe distillate recoveredffrom receiver 24 `and. are ypreferably of higher. boiling charac-v teristics than the"secondary charging stock or contain ra, substantial quantity of materialsmboiling above the range `of the 'secondary .chargingv stock. Y The components of the mixture of `pre'` y.viously cracked and virgin oils thus suilbliedto nearing coil' i` are, therefore,I suitable for treatf- L. ment under the samelcracking cQnditions to projduce high yields of gasoline of good antiknock value. A

The highboiling fractions ofthe reflux condensate supplied to heating coil '6 preferablyl are substantially devoid of` any components Aboiling below the range of the primary charging stock supplied to heatingV coil B or within the range` of the low-boiling reiiuxwcondensate fractions supplied to fractionating methods and apparatus necessitated by economic considerations therer will ordinarily be some overlapping of the various fractions sep-h arated in fractionator I8 but preferably, in the present processthe components of the low-boi1ing fractions of the 'reflux condensate, which boil'r gasoline product collecting in receiver 24, do `noty exceed approximately 5 to 6' within the range of the heating coil 40 and contain yany`coin. ponents ofthe reflux Icondensate', of higherboiling characteristics than'the' primary charging stock.^

Itwill, of course, bey understood that Withthe percent andthe "components 'of the high-boiling..

fractions of they refluxcondensate which boil' the lower boiling fractions supplied to heating coil V4I) are also kept' ata minio.

wihr o economic fractionating within the range of mum consistent methods` and means. A

The preferred operatingconditions which mayA be employed to produce the desired results in an apparatus such as illustratedand above described are approximately asf follows: The 4temperature y employed at the outlet from the nrst mentioned heating coil is preferablyA of `the Order of 800 Yto f 950 F. and the pressure employed at this I point in the'system may range: for example, fromMlOO to 500 pounds, or

mentioned heating erably is substantially the same as thatemployed' in the'vcommunicating heating coil utilizing the lowest pressure, which is usually the first men-I tioned heating coil, and the average temperature o thereabouts, per sq. in.l Thetcmn .50 perature employed at the outlet from the second in the reaction chamber preferably is substan-v tially thesame or somewhat higher than that emj ployed at the outlet from the firstmentioned heat ing coil. The coking chamber is preferably operated at a substantially reduced pressure relative to that employed in the reaction chamber and may range, for example, from pounds, or

thereabouts, per sq..in. down to substantially at,- t

mospheric pressure. The fracti0natingcondens ing and collecting portions of the System preferabove appximately 600 F., to a cracking temperature of approximately 930 F. at a superatmospheric pressure of approximately 400 pounds per sq. in., as measured atthe outlet from the heating coil to which these materials are supplied. The secondary charging stock comprises a straight-run gasoline from paraiinic crude and is subjectedin a separate heating coil, together with the fractions of the reflux condensate boiling be,- tween approximately 400 to 620 F., to an outlet conversion temperature of approximately 1000 F.` at a superatmospheric pressure, measured at the outlet from the heating coil, of approximately 650 pounds per sq. in. Approximately 60 percent of the total products from the last mentioned heating coil are supplied to the reaction chamber and the remaining 40 percent, or thereabouts, are introduced into the coking chamber, which latter zone is operated at a superatmospheric pressure of approximately 50 pounds per sq. in. Substantially the same pressure is employed in the fractionating, condensing and collecting portionsof the system. This operation will yield, per barrel of total charging stock, approximately 75 percent of 400 F. end-point gasolinehaving an antiknock valueof approximately 70, by the motor method, and approximately 17 pounds of low volatile coke, the remainder being chargeable, principally, to uncondensable gas. p

I claim as my invention: l 1

1. A process for the pyrolytic conversion of hydrocarbonvoils which comprises heating a virgin charging oil heavier than gasoline to cracking temperature at substantial superatmospheric pressure in a heating coil, introducing the resultant heated products into an enlarged reaction chamber also maintained at substantial 'superatmospheric pressure, causing both vaporous and liquid components of saidheated products to pass 50 through substantially the entire length of said ing.

chamber, withdrawing said products from the chamber and introducing the same into a reduced pressure vaporizing zone wherein .vapors are separated fromresidue, subjecting vaporous products from the vaporizingzone to fractionation, whereby their components boiling above the range of the desired gasoline product of the process are condensed as reflux condensate, subjecting vapors remaining uncondensed by said fractionation to -cooling and condensation, recovering as the resulting distillate a good quality gasoline, simultaneously subjecting a secondary virgin charging oil, of lower boiling characteristics than the first mentioned charging oil and containing atleast a substantial quantity of vcomponents of poor antiknock value boiling within the range of gasoline, to a higher cracking temperature than the first mentioned charging oil and to substantial superat'mospherc pressure in a separate heating coil, whereby to materially improve the antiknock value of its gasoline components, commingling highly heated products discharged from said sep-v arate heating coil with the heated products from the first mentioned heating coil and `causing the commingled materials to pass through substan-v tially the entire length of the reaction chamber, whereby to increase the temperature and rate of cracking of the total products from the first mentioned heating coil in therreaction chamber, supplying to said separate heating coil components of said reflux condensate which are of higher boiling characteristics than Asaid secondary charging oil and are substantially devoid of components boiling within the range of said gasoline product, whereby to subject the same to further cracking with said secondary charging oil.

2. A process such as defined in claim' 1 wherein a portion of said reflux condensate is returned to the rst mentioned heating coil for further crack- 3. A process such as ydefined in claim 1 wherein a regulated portion of said highly heated products discharged from said separate heating coil is introduced into the vaporizing zone. f l

4. A process such as defined in claim 1 wherein a portion of said reflux condensate is-returned to the first mentioned heating coil for further cracking and wherein a regulated portion of said highly heated products discharged from said separate heating coil is introduced into the vaporizing zone.

.JACQUE C. MQRRELL.

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