US2167507A - Conversion of hydrocarbon oils - Google Patents

Description

July 25, 1939. J. B. HEID CONVERSION OF HYDROCARBON'OILS Filed Oct. 12, 1935 mm mmm wnzou INVENTOR TORNEY m E H m M A J N E B C A J Patented July 25, 1939 UNITED STATES ATENT OFFICE Jacob B. Heid, Chicago, lll., assigner to Universal Oil Products Company, Chicago, lill., a corporation of Delaware Application October 152, 1935, Serial No. 44,646

3 Claims.

This invention particularly refers to an improved process for the selective conversion of hydrocarbon oil charging stock for the process, residual liquid resulting from said conversion, 5 and intermediate liquid products of both cracking operations, for the production of major yields of desirable light distillate, such as motor fuel of good antiknock value, and minor yields of good quality residual liquid or coke and gas.

In one specic embodiment, the present invention comprises subjecting hydrocarbon oil charging stock for the process to conversion conditions of cracking temperature and superatmospheric pressure in a heating coil, introducing the resulting heated products into a reduced pressure vaporizing chamber wherein separation of vaporous and liquid conversion products is accomplished, withdrawing liquid conversion products from said vaporizing chamber, subjecting the same to independently controlled conversion conditions of cracking temperature and superatmospheric pressure in a separate heating coil, introducing the heated products from said separate heating coil into another vaporizing and separating or coking chamber, wherein the final residual liquid conversion product of the process is separated from vaporous conversion products, and either withdrawn from the system or reduced therein to coke, supplying the vaporous conversion products from said separate vaporizing and separating chamber to the first mentioned vaporizing and separating chamber, wherein high boiling components of the vapors are condensed, collected with the liquid conversion products from the iirst mentioned cracking step, and supplied therewith to said separate heating coil, withdrawing vaporous conversion products remaining uncondensed from the first mentioned vaporizing and separating chamber, subjecting the same to fractionation for the formation of reux condensate, subjecting fractionated vapors of the desired end boiling point to condensation, co1- lecting and separating the resulting distillate and gas, subjecting said reflux condensate to independently controlled conversion conditions of cracking temperature and superatmospheric pressure in another separate heating coil and communicating enlarged reaction chamber, withdrawing both vaporous and liquid conversion products from said reaction chamber, and introducing the same into said separate Vaporizing and separating chamber.

As an alternative to the method of operation above outlined, which however is not to be considered equivalent, the heated products from the last mentioned heating coil, instead of being subjected to continued conversion in a high pressure reaction chamber, may be supplied, all or in part, direct to said separate vaporizing and separating chamber. On the other hand, the heated products from both the second mentioned and last mentioned heating coils may, when desired, be supplied to the reaction chamber for further conversion.

It is also within the scope of the invention, particularly in case the charging stock comprises an oil of relatively high boiling characteristics or contains a relatively large proportion of high boiling materials, to eliminate the first-mentioned heating coil and to supply the charging stock directly to the first mentioned vaporizing chamber, wherein it is subjected to substantial Vaporization by Contact with the hot vaporous products from said separate vaporizing and separating chamber.

The accompanying diagrammatic drawing illustrates one specific form of apparatus for carrying out the invention.

Referring to the drawing, hydrocarbon oil charging stock for the process is supplied through line l and valve 2 to pump 3, by means of which it is fed through line 4 and may be directed through valve 5 in this line to heating coil 6. Heating coil Ei is located within a furnace 1 of any suitable form, by means of which the required heat is supplied to the oil passing through the heating coil to subject the same to the desired conversion conditions of cracking temperature and superatmospheric pressure in this Zone. The heated products are discharged from heating coil 6 through line 8 and valve 9 into vaporizing and separating chamber It. It will be understood, of course, that'the charging stock may, when desired, be preheated in any well known manner not villustrated in the drawing to any desired temperature below that at which substantial conversion thereof will occur prior to its introduction into heating coil 6.

Chamber may be operated at any desirable pressure ranging from pounds or thereabouts 45 per square inch superatmcspheric down to substantially atmospheric pressure and is preferably operated at a substantially reduced pressure relative to that employed in the outlet from the heating coil.v Separation of the vaporous and liquid conversion products from this zone is accomplished in chamber l0 by means oi' their contained heat assisted by their reduction in pressure. The relatively high boiling liquids remaining unvaporized in chamber l@ are withdrawn 55 from the lower portion of this zone through line E3 and valve M to pump l5, by means of which they are supplied through line I6 and valve il to conversion in heating coil i3 under independently controlled conversion conditions of cracking temperature and superatmospheric pressure. Heat for conversion of the relatively high boiling oil, passing through heating coil I8, is supplied thereto from a furnace i9 of any suitable form, and heated products from this zone are directed through line 2G, and valve 2l into another vaporizing and separating chamber 23.

Chamber 23 is preferably operated at a substantially reduced pressure relative to that employed at the outlet from heating coil i8, which however is somewhat higher than the pressure employed in chamber I0. Separation of vaporous and residual liquid conversion products is accomplished in chamber 23. The latter may be withdrawn from the lower portion of this Zone and directed through line 24 and valve 25 to cooling and storage, or elsewhere as desired, or when desired they may be reduced in chamber 23 to substantially dry coke. In the latter case, the coke may be allowed to accumulate within chamber 23, to be removed therefrom in any well known manner not illustrated after this Zone has been substantially lled with coke or after its operation has been completed for any other reason, and after it has been isolated from the rest of the process. It will be understood that a plurality of coking chambers may be employed, when desired, although not illustrated, in which case they preferably are alternately operated, cleaned and prepared for further operation. In case coking is employed in chamber 23, line 24 may serve as a drain line and may also serve, when desired, as a means of introducing steam, water or other suitable cooling material into the chamber in order to hasten cooling and facilitate removal of coke.

The vaporous conversion products supplied to chamber 23, as well as any vapors evolved in this zone, are Withdrawn from the upper portion thereof and directed through line 26 and valve 2T into chamber l0, wherein they commingle with the charging stock or with the conversion products from heating coil 6, and wherein any heavy components of the vaporous products unsuitable for conversion, together with reux condensate, may be separated therefrom and supplied, together with other heavy liquids from this Zone, to conversion in heating coil I8, as previously described.

The total vaporous conversion products of the process remaining uncondensed in chamber lil are withdrawn from the upper portion thereof and directed through line 28 and valve 29 to fractionation in fractionator 33. The components of vapors supplied to fractionator 3B boiling above the range of the desired final light distillate product of the process are condensed in this zone as reflux condensate. Fractionated vapors of the desired end boiling point are withdrawn, together with uncondensable gas produced in the operation, from the upper portion of fractionator 3) and are directed through line Si and valve 32 to condensation and cooling in condenser 33, The resulting distillate and gas passes through line and valve 35 to collection and separation in receiver 35. Uncondensable gas may be released from the receiver through line 3l and valve 38. Distillate may be withdrawn from receiver 35 through line 39 and valve #i9 to storage or to any desired further treatment.

When desired, a regulated portion of the distillate collected in receiver E@ may be recirculated by well known means (not illustrated) to the upper portion of fractionatcr 3i! to serve as a cooling and reuxing medium in this zone for assisting fractionation of the vapors and to maintain the desired vapor outlet temp ature.

The reflux condensate formed in ac"onator 30 may be withdrawn from the low portion of this zone through line #il and valve to pump 43, by means of which it is fed through line lli and valve (l to heating coil d5.

Heating coil l5 is located in a furnace l? of any suitable form, by means of which heat is supplied to the oil passing through the heating coil to subject the same to independently controlled conversion conditions of cracl "ng temperature and superatmospheric pressure. The heated products are discharged from heating coil 46 through line 48 and are directed through valve 49 in this line into reaction chamber 5l.

It is also within the scope of the present invention, when desired, to introduce all or a regulated portion of the heated products from heating coil I8 into reaction chamber 5l by means of line 2li', valve 22 and line 49.

Reactie-n chamber is preforably maintained at a substantial superatmospheric pressure which may be substantially the same or somewhat lower than the pressure employed at the outlet from heating coil ilil, or from heating coil i8 in case products from the latter zone are supplied to the reaction chamber and heating coil i8 is operated at a lower pressure than that employed in heating coil 46. The conversion products supplied to the reaction chamber, and particularly their vaporous components, are subjected to appreciable further conversion, in this Zone, and preferably although not illustrated is insulated in order to conserve heat. In the case here illustrated both vaporous and conversion products are withdrawn in commingled state from the lower portion of chamber 5l and are directed through line 53, valve 5d, into chamber 23.

The preferred range of operating conditions which may be employed in accordance with the process of the present invention utilizing an apparatus such as illustrated and above described may be approximately as follows: The heating coil wherein the charging stock is subjected to conversion may employ an outlet conversion temperature ranging for example from 800 to 950 F., preferably with a superatmospheric pressure at this point in the system of from 100 to 500 pounds or more per square inch. The succeeding vaporizing chamber, as previously mentioned, is preferably operated at a substantially reduced pressure, which may range for example from 100 pounds per sduareinch superatrnospheric pressure down to substantially atmospheric pressure, and the pressure employed in this zone may be substantially equalized or reduced in succeeding fractionating, condensing and collecting portions of the system. The heating coil to which the residual liquid from said vaporizing chamber is supplied may utilize an outlet conversion temperature ranging for example from 800 to 1000 F'. or thereabouts, preferably with a superatmospheric pressure at the outlet from this zone ranging from 30 pounds or thereabouts per square inch to 300 pounds or more per square inch. The heating coil to which the reflux condensate is supplied for conversion may utilize an outlet temperature ranging for example from 900 to 1000 F., preferably with a superatrnospheric pressure at this point in the system of from 200 to 800 pounds or more'per square inch. The reaction chamber, as previously mentioned, may be operated at a atmospheric pressure substantially the same or somewhat lower than that employed in the preceding heating coil utilizing the lowest pressure. The vaporizing or coking chamber to which products fromthe reaction chamber are supplied, in case the reaction chamber is utilized, is operated at a superatmospheric pressure of from 30 to 100 pounds,`orthereabouts, per square inc h, which however is somewhat higher than the pressurev4 employed in the first mentioned vaporizing chamber, and is preferably somewhat lower than the pressure employed in the reaction chamber or in the preceding heating coils.

As a specific example of the operation of the process of the present invention as it may be accomplished in an apparatus such as illustrated and above described, the charging stock, which comprises a 30 A. P, I. gravity Mid-Continent topped crude, is subjected in the rst heating coil to an outlet conversion temperature of approximately 930 F. at a superatmospheric pressure of about 300 pounds per square inch, and the succeeding vaporizing chamber to which the products from this heating coil are supplied is operated at a superatmospheric pressure of approximately 50 pounds per square inch. The liquid products from this vaporizing chamber are quickly heated in a separate heating coil to an outlet conversion temperature of approximately 980 F. at a superatmospheric pressure of about 60 pounds per square inch and are introduced into a coking chamber maintained at substantially the same pressure. The reflux condensate is heated in another separate heating coil to an outlet conversion temperature of approximately 950 F. at a atmospheric pressure of about 350 pounds per square inch, and the heated products from this zone are introduced into a reaction chamber maintained at substantially the same pressure. Both vaporous and liquid products from the reaction chamber are supplied to the coking chamber. Vaporous products from the coking chamber are supplied to the same vaporizing chamber to which the heated products from the charging stock heating coil are supplied, and the vaporous products from this zone are subjected to fractionation for the formation of reux condensate and recovery of desirable light distillate. This operation will yield, per barrel of charging stock, approximately of motor fuel of good anti-knock value, and approximately 75 pounds of low volatile coke, 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 for the process to cracking temperature and superatmospheric pressure in a heating coil, introducing the heated products into a reduced pressure vaporizing chamber wherein vaporous and liquid conversion products are separated, withdrawing the latter from the vaporizing chamber and subjecting the same to independently controlled conditions of cracking temperature and superatmospheric pressure in a separate heating coil, introducing heated products from said separate heating coil into a colring chamber wherein the non-vaporous high-boiling conversion products are reduced to coke, Withdrawing the vaporous products from the coking chamber and introducing the same into the vaporizingand separating chamber, subjecting vaporous products from the vaporizing and separating chamber to fractionation for the formation of reux condensate comprising their insufficiently converted components, subjecting fractionated vapors of the desired end boiling point to condensation, recovering the resulting distillate, subjecting reux condensate formed by said fractionation toindependentIy controlled conversion conditions of cracking temperature and superatmospheric pressure in another separate heating coil and communicating enlarged reaction chamber, and introducing both vaporous and liquid conversion products from the reaction chamber into the coking chamber, the process being further characterized in that at least a regulated portion of the heated products from the second-mentioned heating coil is passed through said reaction chamber prior to their introduction to the coking chamber.

2. In a process for the conversion of hydrocarbon oils, wherein reflux condensate, comprising insufficiently converted intermediate liquid conversion products of the process, is subjected to conversion conditions of cracking temperature and superatmospheric pressure in a heating coil and communicating reaction chamber, both vaporous and liquid conversion products withdrawn from the reaction chamber and introduced into a coking chamber wherein their high-boiling nonvaporous components are reduced to coke, the improvement which comprises introducing vaporousproducts from the coking chamber into a vaporizing and separating chamber, simultaneously heating hydrocarbon oil charging stock for the process to cracking temperature under pressure in a separate heating coil and then introducing the same to said vaporizing and sepa.- rating chamber, wherein it is contacted with the hot vaporous products from the coking chamber, withdrawing unVapo-rized high-boiling fractions of the charging stock and high-boiling components of the vaporous products, which are condensed in the vaporizing and separating chamber, from the latter zone, subjecting the same to independently controlled conversion conditions of cracking temperature and superatmospheric pressure in another separate heating coil, introducing separate portions of the resulting heated products into the reaction chamber and into the coking chamber, withdrawing vaporous components of the charging stock and components of the vaporous` products from the coking chamber remaining uncondensed in the vaporizing chamber from the latter zone, subjecting the same to fractionation for the formation of said reflux condensate, subjecting fractionated vapors of the desired end boiling point to condensation, and recovering the resulting distillate.

3. In a process for the conversion of hydrocarbon oils, wherein reflux condensate, comprising insufficiently converted intermediate liquid conversion products of the process, is subjected to conversion conditions of cracking temperature and superatmospheric pressure in a heating coil and communicating reaction chamber, both vaporous and liquid conversion products withdrawn from the reaction chamber and introduced into a reduced pressure vaporizing and separating chamber, wherein vaporous and residual liquid conversion products are separated, and the latter recovered, the improvement which comprises introducing vaporous products from the Vaporizing and separating chamber into a second vaporizing and separating chamber, simultaneousing temperature and superatmospheric pressure in another separate heating coil, introducing sep arate portions of the resulting heated products into the reaction chamber and into. said reduced pressure chamber, withdrawing commingled charging oil vapors and cracked vapors from said second vaporizing chamber, subjecting the same to fractionation for the formation of said reflux condensate, subjecting fractionated vapors of the desired end boiling point to condensation, and recovering the resulting distillate.

JACOB B. HEID.

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