US1948713A - Treatment of hydrocarbon oils - Google Patents

Description

Feb. 27, 1934. L. c. HUFF 3 TREATMENT OF HYDROCARBON OILS Filed Nov. 10, 1930 INVENTOR LYMAN C. HUFF ATTORNEY Patented Feb. 27, 1934 UNITED ATES PATENT oFncI;

sal Oil Products Company, corporation of South Dakota Chicago, 111., a

Application November 10, 1930 Serial No. 494,616

' Claims.

This invention relates to the treatment of hydrocarbon oils and refers particularly to the cracking of relatively heavy oils for the manufacture of products of a more valuable nature.

In a cracking process in which hydrocarbon oils are subjected to conversion conditions and the vapors and unvaporized materials are separated, the vapors passing to iurther treatment and the unvaporized residual oil passing to a zone in which it is subjected to further vaporization, the present invention contemplates the improvement comprising subjecting the vapors evolved from the revaporization of the residual oil to partial condensation, subjecting the uncondensed vapors to further treatment and returning the condensed heavier components of the vapors into the stream of heated materials which have been subjected to conversion temperatures.

The novelty and utility of the present invention will be more apparent with reference to the attached diagrammatic drawing illustrating one form of apparatus embodying the features oi the present invention.

Thefollowing description of the drawing embraces also a description of the process oi? the invention. Raw oil charging stock is supplied through line 1 and valve 2 to pump 3, may be fed through line 4 and valve 5 into fractionator 6 or may pass, all or in part, through line? and 80 valve 8 into fractionator 9 or, if desired, any portion or all of the raw oil charging stock from pump 3 may pass through line 10 and valve 11 into line 12 and thence direct to heatingelement 13. The raw oil supplied to iractionator 6 is 85 preheated by contact with the relatively hot vapors in this zone, which it assists in fractionating,

and passes together with their heavier condensed portion through line it and valve 15 to pump 16 irom which the combined materials are fed through line 1'7, valve 13 and, line 7 into fractionator 9 or from line 17, through line 19 and valve 20 into line 10 and thence through line 12 to heating element 13. The oil supplied to fractionator 9, including raw oil from pump 3, if any is fed in this direction, and raw oil combined with reflux condensate, from fractionator 6, assists in the fractionation of the relatively hot vapors in fractionator 9 passing together with their heavier condensed portion through line 21 and valve 22 to pump 23 from whence thev combined materials are fed through line 12 and valve 24 to heating element 13. The oil fed to heating element 13, which is located in any suitable furnace 25, in any of the manners described is subjected to the desired conversion temperatures under any desired pressure conditions and passes through line 26 and valve 27 into reaction chamber 28.

- Separation of vapors and unvaporized material is permitted in chamber 28. The vapors pass through line 29 and valve 30 to fractionator 9 0 where they are ,subjected to fractionation, their heavier portions being condensed and returned to the heating element, as already described, while their lighter portions pass through line 31 and valve 32, are subjected to condensation and cooling in condenser 33, products from which pass through line 34 and valve 35 to be collected in receiver 36. Distillate may be withdrawn from receiver 36 through line 3'? and valve 38. Uncondensable gas may be released through line 39 controlled by valve 40. A portion of the distillate may be withdrawn from receiver 36 through line 41 and valve 42 and recycled by means of pump 43 through line 44 and valve 45 to fractionator 9 to assist fractionation of the vapors in this [6 zone.

U'nvaporized residual oil from chamber 26 is withdrawn through line 46 controlled by valve 47 to chamber48, which is maintained at reduced pressure relative to the pressure employed in chamber 28, permitting vaporization of the light components of the residual liquid introduced thereto. The heavier components of the residual liquid remaining unvaporized in chamber 43 may be withdrawn through line 49 and valve 50 to 65 further treatment or to storage or, if so desired, by heating chamber 48 or by other well known means, not shown, suchas introducing relatively hot liquid. or vapors from the process into the body of unvaporized material within the chamher, conditions may be so regulated within charm ber 48 that only substantially dry coke will remain therein. In case non-residuum operation of this character isemployed a plurality of chambers, not shown in the drawing, similar to chamber iii may be utilized alternately or in parallel to permit prolonged operation of the process.

Vapors evolved from the vaporization of the re-. sidual liquid in chamber 43 pass through line 51 and valve 52 to partial condenser 53 wherein their heavier components are condensed by indirect heat exchange with any desirable cooling material such as water or any relatively cool liquid from the process introduced to cooling coil 54, which is located in partial condenser 53, through line 55 and valve 56 and withdrawn therefrom through line 5'? and valve 56. The heavier COUL- ponents of the vapors condensed in partial condenser 53 pass through line 59 and valve 60 to pump 61 from which they Ill-ii through line 62, 119

materials from heating element 13 and cooling these heated materials to the desired temperature.

The condensate instead of passing directly through line 63 and valve 64 may pass, all or in part, through line 67, valve 68, cooler 69 and valve 70 into line 65, thus furnishing a means of controlling the temperature of the cooling material introduced into line 26.

A portion of the vap'ors from chamber 48 instead of passing through line 51 and valve 52 into partial condenser 53 may be diverted from line 51 through line '71 and valve 72, thus furnish-' ing a means of controlling the quantity of vapors supplied to partial condenser 53 and hence the quantity of condensate removed from the vapors for cooling purposes in line 26. Uncondensed vapors from partial condenser 53 are withdrawn through line 73 and valve '74, uniting in line '71 with that portion, if any, of the vapors which do not enter partial condenser 53 and pass therewith through valve 75, in line 71, to fractionator 6. Vapors introduced into fractionator 6 are subjected to fractionation, their heavier portions being returned, together with preheated raw oil introduced into this zone, to fractionator 9 or direct to heating element 13 or in part to both, as already described. Uncondensed vapors from fractionator 6 pass through line 76 and valve '77, are subjected to condensation and cooling in condenser 78, products from which pass through line 79 and valve 80 to be collected in receiver 81. Distillate may be withdrawn from receiver 81 through line 82 and valve 83. Uncondensable gas may be released through line 84 controlled by valve 85.

Pressures employed within the system may range from sub-atmospheric to super-atmospheric pressures as high as 1500 pounds or more per square inch. Substantially equalized or differential pressures may be employed in the cracking system while the residuum redistilling system is preferably operated under reduced pressure relative to the pressure employed in the reaction chamber of the cracking system, which pressure may be substantially equalized throughout the residuum redistilling system or the various elements thereof may be operated under differential pressures.

Conversion temperatures employed in the cracking system may range from 750 to 1200 F., more or less. Preferably, however, the temperature of the oil leaving the heating element is reduced to within the range of relatively low cracking temperatures, say 750 to 900 F., or may, if desired, be reduced to below the cracking temperature, by the introduction of the relatively cool condensed heavy components of the vapors from the flash distilling system, as provided by the invention. i

As a specific example of operating conditions which may be employed in the operation of the improved process of the present invention and results which may be obtained from such operation, a relatively heavy Mid-Continent gas oil of about 32 A. P. I. gravity is the charging stock for the system and is subjected, together with reflux condensate from the fractionator of the cracking system and reflux condensate from the fractionator of the flash distilling system, to a temperature of approximately 980 F. under a pressure of about 350 pounds per square inch. The oil leaving the heating element is cooled to a temperature of about 875 F. by the introduction of a clean distillate resulting from the condensation of the heavier components of the vapors from the residuum redistilling chamber, which are'themselves subjected to conversion by heat exchange with the relatively hot converted materials which they serve to cool. The pressure upon the reaction chamber is reduced to about 150 pounds per square inch and this pressure is substantially equalized throughout the succeeding portions of the cracking system. The

residuum redistilling system'is maintained under a substantially equalized pressure of approximately 30 pounds per square inch.

In this operation about 58 percent of motor fuel, having an anti-knock value equivalent to a blend of about 50 percent benzol and 50 percent straight-run Pennsylvania gasoline; may be produced, based on the raw oil charged. In addition about 12 percent of pressure distillate bottoms, resembling good quality gas oil and suitable for sale as furnace distillate or for use as charging stock for cracking, is produced and about 22 percent of residual oil possessing characteristics which render it suitable for sale as good quality fuel is obtained, the remaining 8 percent or thereabouts is chargeable to gas, loss and a relatively insignificant amount of coke.

I claim:

1. A process for converting hydrocarbon oil which comprises subjecting oil to cracking conditions in a heating zone, reacting the heated oil in a reaction zone with the separation of vapors and unvaporized residue, withdrawing residue from the reaction zone; and subjecting it to distillation in a zone of reduced pressure with the formation of further vapors and residue separately, subjecting the first-named vapors and the last-named vapors to partial condensation, then withdrawing the heavy components of the last-named vapors as condensate and commingling the same without prior heating to cracking temperature with heated oil from the heating zone prior to its entrance into the reaction zone .distilled by pressure reduction with the formation of flash vapors; the improvement which comprises .fractionating the flashed vapors thereby forming reflux condensate, introducing at least a portion of the reflux condensate, withoutprior heating to cracking temperature, into the heated oil discharging from the heating zone to thereby cool and heated oil, separately fractionating the vapors removed from the reaction zone and returning a substantial portion of the reflux condensate separated therefrom to the heating zone for retreatment therein.

4. In a hydrocarbon oil cracking process of the character wherein the oil is heated to cracking temperature under pressure while passing in a restricted stream through 'a heating zone, the heated oil thence discharged into a reaction zone from which vapors and unvaporized oil are separately withdrawn and the vapors fractionated and the unvaporized oil flash distilled by pressure reduction with the formation of flashed vapors; the improvement which comprises separately fractionating the flashed vapors to form relatively heavier and lighter reflux con densates, introducing the heavier condensate to character wherein the oil is heated to cracking temperature under pressure while passing in a restricted stream through a heating zone, the heated oil thence discharged into a reaction zone from which vapors and unvaporized oil are separately withdrawn and the vapors fractionated j'P- Patent No. 1,948,

and the unvaporized oil flash distilled by pressure reduction with the formation of flashed vapors; the improvement which comprises condensing a portion of the flashed vapors out of direct contact with charging oil to form a relatively clean.

distillate, dephlegmating another portion 0! the flash vapors in direct contact with charging oil for the process thereby forming a mixture of reflux condensate and preheated charging oil separately fractionating the first-mentioned vapors, introducing said relatively clean condensate into the heated oil discharging from the heating zone to serve as a cooling medium therefor, and supplying said mixture to the heating zone for treatment therein.

LYMAN C. HUFF.

CERTIFICATE OF CORRECTION.

February 27-, 1934.

LYMAN c. aura.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2. line 132, claim 3, for "'flash" read flashed; and line 12,8, same claim, for "and" read the; and

that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 3rd day of April, A. D. 1934. 1

(Seal) F. M. Hopkins Acting Commissioner of Patents.

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