US2100849A - Conversion of hydrocarbon oils - Google Patents

Description

CONVERSION OF HYDROCARBON OILS Filed Aug. 17, 1935 C OZ 1772 72 furnace Furnace 40 Patented Nov. 30, 1937 UNITED STATES EATENT OFFICE Jacob B. Heid, Chicago,

Ill., assignor to Universal l@il Products Company, Chicago, Ill., a corporation of Delaware Application August 17, 1935, Serial No. 36,616

5 Claims.

This invention particularly refers to an improved process for the conversion of hydrocarbon oils to produce primarily high yields of desirable light distillate such as motor fuel of good antiknock value and good quality liquid residue'.

In the present process the charging stock is subjected to relatively mild conversion, desirable light distillate recovered from the resulting products b-y fractionation and condensation and the remaining higher boiling products separated into intermediate fractions (reux condensate) and residual liquid, the residual liquid subjected to a relatively mild cracking or viscosity breaking operation and introduced into a vaporizing chamber, the intermediate fractions subjected to more severe conversion conditions in a separate heating coil and communicating reaction chamber, the resulting liquid conversion products subjected to further vaporization in said vaporizing chamber, the vaporous products from: the last mentioned cracking operation subjected to fractionation together with the vaporous products from said vaporizing chamber, the reilux condensate resulting from the last mentioned fractionating step returned to the last mentioned cracking stage for further conversion and fractionated vapors of the desired end-boiling point subjected to condensation for the recovery of the desired light distillate product.

The accompanying diagrammatic drawing illustrates one specific form. of apparatus embodying the features of the present invention.

Referring to the drawing, hydrocarbon` oil charging stock for the process, which may be any desired type of oil but is normally an oil of relatively wide boiling range or of relatively highboiling characteristics, is supplied through line I and Valve 2 to pump 3 by means of which it is fed through line l and valve E into heating coil E. The charging stock may, of course, be preheated, when desired, in any well known manner not illustrated, prior to its introduction into the heating coil.

A furnace l of any desired form supplies the required heat to the oil passing through heating coil ii to subject the same to the desired conversion temperature, preferably at a substantial superatmospheric pressure and the heated products are discharged from the heating coil through line 8 and Valve 9 into separating chamber Il).

Chamber i is preferably operated at a substantially reduced pressure relative to that employed in heating coil 6 but may, when desired, be operated at substantially the same pressure as that employed in the outlet from the heating coil.

Separation of Vaporous and liquid conversion products is accomplished in chamber IIJ, the latter being withdrawn from the lower portion of this zone through line l! and valve I2 to pump I3 by means of which it is supplied through line Ill and valve I5 to heating coil I6 for further treatment, as will be later more fully described.

In the case here illustrated separating chamber lil comprises the lower portion of column I'I, the upper portion of which comprises fractionator I8, and the vaporous conversion products from chamber it pass through a suitable partition I9 into the iractionator wherein their components boiling above the range of the desired light distillate product of this stage of the process are condensed as reflux condensate.

Fractionated vapors of the desired end-boiling point are Withdrawn, together with uncondensable gas produced by the operation, from the upper portion of fractionator I8 through line 20 and may be directed through Valve 2| in this line to condensation and cooling in condenser 22. 'Ihe resulting distillate and gas passes through line 23 and valve 2li to collection and separation in receiver 25. Uncondensable gas. may be released from the receiver through line 26 and Valve 2'I. Distillate may be withdrawn from' receiver 25 through line 28 and valve 29 to storage or to any desired further treatment. When desired, a regulated portion of the distillate collected in receiver 25 may be recirculated by well known means, not shown in the drawing, to the upper portion of fractionator I3 to serve as a coolingand reuxing medium in this zone.

The reuX condensate formed in fractionator I8 may be Withdrawn from the lower portion of this zone through line 33 and valve 34 to pump 35 by means of which it is supplied through line 36, valve 31 and line 38 to heating coil 39 for further conversion.

Heating coil 39 is located within a furnace 4I) of any suitable form by means of which the oil supplied to this Zone is subjected to the desired be withdrawn in commingled state fromv the lower portion of chamber 43 and directed through line 44 and valve 45 into reduced pressure vaporizing chamber 45. However, when desired, separation of the vaporous products and liquid conversion products may be accomplished in the reaction chamber, in which case the liquid conversion products may be directed to chamber 46, in the manner previously described, either alone or together with a regulated portion of the vaporous products from the reaction chamber, while the total or the remaining portion of the vaporous products are separately removed from any suitable point above the point of removal of the liquid conversion products and in the case here illustrated are directed through line 4l, valve 48 and line 49 to fractionation in fractionator 59, although the vaporous products from chamber 43 may, when desired, be introduced, all or in part, by well known means not illustrated, into chamber 46.

Heating coil i6 is supplied with the required heat from a furnace 5I of any suitable form by means of which the liquid conversion products from chamber H3 are subjected to relatively mild conversion or viscosity breaking under the desired conversion conditions of elevated temperature and superatmospheric pressure, the heated products being discharged from heating coil l5 through line 52 and valve 53 into vaporizing chamber 46.

Chamber 46 is preferably maintained at a substantially reduced pressure relative to that employed in reaction chamber 43 by means of which further vaporization of the liquid conversion products supplied to this zone from the reaction chamber is accomplished. Separation of vaporous and residual liquid components of the heated products supplied to this zone from heating coil i6 is also accomplished in chamber 45. The residual liquid remaining unvaporized in this zone is withdrawn from the lower portion thereof through line 54- and valve 55 to cooling and storage or elsewhere, as desired. The vaporous conversion products supplied to chamber 40 and the vapors evolved in this Zone are withdrawn from the upper portion thereof through line 5S and valve 51 and are directed through line 49 to fractionation in fractionator 59.

The components of the vaporous products supplied to fractionator 59 boiling above the range of the desired final light distillate product are condensed in this Zone as reflux condensate. The reiiux condensate is removed from the lower portion of the fractionator through line 60 and valve 5| to pump Si. by means of which it is returned through line 03, valve 54 and line 38 to further conversion in heating coil 39 together with the reflux condensate from fractionator I8, which is supplied to this zone in the manner previously described.

Fractionated vapors of the desired end-boiling point are withdrawn from the upper portion of fractionator 59 through line 65 and valve S6 and are subjected to condensation and cooling in condenser 5'5. The resulting distillate and gas passes through line 5S and valve 5S to collection and separation in receiver l0. Uncondensable gas may be released from the receiver through line 'H and valve '12. Distillate may be withdrawn from receiver 'i9 through line 73 and valve i4 to storage or to any desired further treatment. When desired, a regulated portion of the distillate collected in receiver lil may be recirculated by well known means, not shown in the drawing, to the upper portion of fractionator 59 to serve as a cooling and refluxing medium in this zone.

In a process such as illustrated and above described, the preferred operating conditions may be approximately as follows: The heating coil to which the charging stock is supplied may utilize an outlet conversion temperature ranging, for example, from 800 to 950 F., or thereabouts, preferably with a superatmospheric pressure at this point in the system of from to 500 pounds, or thereabouts, per square inch. The succeeding separating chamber is preferably operated at a substantially reduced pressure relative to that employed in the heating coil although, when desired, this zone may be operated at a substantial superatmospheric pressure up to approximately the same as that employed in the heating coil. The fractionating, condensing and collecting equipment of this stage of the system may be operated at substantially the same or somewhat lower pressures than that employed in the separating chamber. The heating coil to which the reflux condensates from both fractionators of the system is supplied may utilize a conversion temperature, measured at the outlet therefrom, ranging, for example, from 850 to 975 F., or thereabouts, preferably with a superatmospheric pressure at this point in the system of from 100 to 500 pounds or more per square inch. A substantial superatmospheric pressure substantially the same as that employed in the reflux heating coil or somewhat reduced relative thereto may be utilized in the succeeding reaction chamber. The heating coil to which liquid conversion products resulting from said relatively mild conversion of the charging stock are supplied for further conversion or Viscosity breaking may utilize an outlet temperature ranging, for example, from 'Z50 to 900 F., preferably with a superatmospheric pressure at this point in the system of from 100 to 500 pounds, or more, per square inch. The vaporizing chamber is preferably operated, as previously mentioned, 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 pressure employed in the Vaporizing chamber may be substantially equalized or somewhat reduced in the succeeding fractionating, condensing and collecting portions of the system.

As a specific example of the operation of the process of the present invention, charging stock `comprising a Mid-Continent topped crude of about 26 A. P. I. gravity is subjected in the first heating coil of the system to an outlet conversion temperature of approximately 900 F. at a superatmospheric pressure of about 250 pounds per square inch and the heated products are introduced into a separating chamber operated at a superatmospheric pressure of about 50 pounds per square inch. Liquid conversion products are withdrawn from the separating chamber, subjected to a viscosity breaking operation in a separate heating coil employing an outlet conversion temperature of approximately 825 F. and a superatmospheric pressure of about 200 pounds per square inch, the heated products being introduced into a vaporizing chamber operated at a superatmospheric pressure of about 50 pounds per square inch. A distillate of about 350 F. end-boiling point is recovered as the motor fuel product of the first cracking stage and the intermediate fractions (reflux condensate) are subjected in a separate heating coil to an outlet conversion temperature of approximately 940 F. at a superatmospheric pressure of approximately 350 pounds per square inch. 'I'he heated products from the last mentioned heating coil are introduced into a reaction chamber operated at substantially the same pressure and both vaporous and liquid products from this zone are supplied to said vaporizing chamber. The vaporous products from the vaporizing chamber are subjected to fractionation at substantially the same pressure as that employed in the vaporizing chamber, the resulting reflux condensate being returned to the last mentioned heating coil for further conversion and a motor fuel product of about 400 F. end-boiling point being recovered by condensation of the fractionated vapors. This operation will produce, per barrel of charging stock, approximately 59 per cent of motor fuel of good antiknock value and about 32 per cent of heavy liquid residue meeting market specifications for premium fuel oil, the remainder being chargeable, principally, to uncondensable gas.

I claim as my invention:

l. A process for the conversion of hydrocarbon oils which comprises subjecting hydrocarbon oil charging stock containing intermediate and residual portions of petroleum to conversion conditions of cracking temperature and superatmospheric pressure in a first cracking stage, separating the resulting vaporous and liquid conversion products, subjecting the vapors to fractionation whereby their insufficiently converted components are condensed as reflux condensate, recovering a desirable light distillate from the fractionated vapors by condensation, subjecting the reflux condensate to independently controlled conversion conditions of superatmospheric pressure and relatively higher temperature in a second cracking stage of the same system, separating the resulting vaporous and liquid conversion products, subjecting the latter to further vaporization at substantially reduced pressure relative to that at which they are produced, subjecting said liquid conversion products from the first cracking stage to further relatively mild conversion at cracking temperature and superatmospheric pressure for the purpose of materially re'- ducing their viscosity, thereby forming additional vaporous and liquid conversion products, comminglin'g the latter with the nonvaporous conversion products from said second cracking stage and recovering the commingled residual liquids, subjecting the vaporous products from said viscosity reducing operation and from said second cracking stage to fractionation for the formation of reflux condensate, returning the latter to said second cracking stage for further conversion, subjecting fractionated vapors of the desired end-boiling point from the last mentioned fractionating step to condensation, and recovering the resulting distillate.

2, A process for the conversion of hydrocarbon oils which comprises subjecting hydrocarbon charging stock containing intermediate and resdual portions of petroleum to conversion conditions of cracking temperature and superatmospheric pressure in a heating coil, separating the resulting vaporous and liquid conversion products, subjecting the vapors to fractionation for the formation of reflux condensate and the recovery of desirable light distillate from the fractionated vapors by condensation, subjecting the reflux condensate to conversion conditions of superatmospheric pressure and relatively higher temperature in a separate heating coil and communicating reaction chamber, separating the resulting vaporous and liquid conversion products, subjecting the latter to further vaporization in a reduced pressure vaporizing chamber, subjecting said residual liquid from the rst mentioned cracking stage to continued relatively mild conversion at cracking temperature and superatmospheric pressure in a separate heating coil to reduce the viscosity thereof, introducing the heated products from said separate heating coil into said vaporizing chamber, withdrawing non-vaporous residual liquid from the vaporizing chamber, subjecting vaporous products from the vaporizing chamber to fractionation for the formation of reflux condensate, returning said reflux condensate for further conversion to the same heating coil to Which the reflux condensate from the first mentioned cracking stage is supplied, subjecting fractionated vapors of the desired end-boiling point from the last mentioned fractionating stage to condensation, and recovering the resulting distillate.

3. A process as claimed in claim 2 wherein both vaporous and liquid conversion products are withdrawn in commingled state from said reaction chamber and introduced into said vaporizing chamber.

4. A process as claimed in claim 2 wherein vaporous and residual liquid conversion products are separated in said reaction chamber, the latter supplied therefrom to said vaporizing chamber and vaporous products separately Withdrawn from the reaction chamber and supplied to the last mentioned fractionating stage.

5. A process for producing motor fuel and good quality liquid residue from hydrocarbon charging stock containing intermediate and residual portions of petroleum, which comprises heating said charging stock to cracking temperature under pressure in a heating coil and separating the same into vapors and liquid, subjecting fractions of the vapors heavier than gasoline to more drastic cracking conditions than the charging stock in a second heating coil and subsequently separating the same into vapors and unvaporized oil, subjecting said liquid in a third heating coil to relatively mild conversion conditions of a viscosity reducing character and then separating vapors therefrom, combining the remaining unvaporized portion of said liquid with said unvaporized oil and recovering the resultant liquid mixture as a product of the process, introducing the last-named vapors and the second-mentioned vapors to a fractionating zone and fractionating the same therein in admixture, supplying resultant reflux condensate from the fractionating Zone to said second coil for drastic cracking therein together with said fractions heavier than gasoline, and finally condensing and collecting the vapors uncondc-nsed in the fractionating zone.

JACOB B. HEID.

Images