US1972914A - Treatment of hydrocarbon oils - Google Patents

Description

p ,1934- c. H. ANGELL v 1,972,914

TREATMENT OF HYDROCARBON OILS Filed Dec. 19, 1931 FURNACE INVENTOR CHARLES H. ANGELL mww Patented Sept. 11, 1934 UNITED STATES,

TREATMENT OF HYDROCARBON OILS Charles H. Angel], Chicago, Ill.,

assignor to Universal Oil Products Company, Chicago, I'lL, a corporation of South Dakota Application December 19, 1931, Serial No. 582,021"

1 Claim.

This invention relates to the treatment of hydrocarbon oils and more particularly refers to the treatment of crude oils containing gasoline for the purpose of simultaneously topping I the crude, reforming its naturally contained gasoline components to improve their quality and converting its heavier components for the production of substantial yields of lighter products.

10. The treatment of relatively heavy hydrocarbon oils under elevated temperatures and substantial super-atmospheric pressures to effect their conversion into substantial yields of more desirable lower boiling products, such as motor fuel 15, preferably of relatively high antikncck value,

' is now a well known partcf the refining art.

The charging stock for such processes usually comprises oils from which any naturally con tained gasoline has been previously extracted by distillation although some cracking processes incorporate means for topping crude oils, i. e., removing their naturally contained gasoline fractions in the same system in which their heavier components are cracked. Most straightrun gasoline, i. e., gasolines existing in a natural state in petroleum, are of such poor antiknock value as to be unsuitable for use as motor fuel in the modern high compression engines without blending or resorting to the use of knock inhibitors. A more recent development in the cracking art are processes for reforming materials of substantially motor fuel boiling range (straightrun gasoline, for example) primarily to improve their antiknock quality without substantially altering their boiling range.

It is the purpose of the-present invention to incorporate-all of the above described operations, namely, topping, cracking and reforming in a single improved. process and apparatus.

An outstanding feature of the inventionis the simplicity of the process and apparatus by means of which all of the operations mentioned are accomplished.

The primary principles of the invention comprise introducing-a petroleum oil containing desirable light components such as gasoline into the reaction zone: of a cracking system where, by means of the heat imparted thereto by direct contact with the conversion products of the system, said relatively light components are substantially vaporized and, under the elevated temperature and super-atmospheric pressure conditions maintained in thereaction zone,.their antiknock value is materially improved and thence subjecting hea ier components of the raw oil to conversion in the same cracking system for the production of substantial yields of desirable light products such as motor fuel.

The principles of the invention are applicable to many types of cracking systems and are therefore not limited to use in any one particular type of equipment. However, when it is desired to produce fueloil as the residual prodnot of the system, the type of cracking system outlined in the following specific embodiment has been found entirely suitable.

The invention may comprise, in one of its more specific embodiments, subjecting hydrocarbon oil to conversion conditions in a heating element, introducing the heated oil into an enlarged reaction zone, maintaining substantial super-atmospheric pressure within said heating element and reaction zone, subjecting vaporous materials in said reaction zone to continued con- 7 version for a predetermined time while quickly 7,5 separating therefrom non--vaporous products, withdrawing both vaporous and non-vaporous materials from said reaction zone to .a vaporizing zone, preferably maintained under a substantially reduced pressure, wherein further vaporization of said non-vaporous materials from said reaction zone and final separation of vaporous products is effected, subjecting vapors from said reduced pressure zone to fractionation whereby their insufliciently converted components are condensed, being returned therefrom to the heating element for further conversion, supplying to the system as rawoil charging stock, hydrocarbon oil containing components of motor fuel boiling-range and introducing said oil into said reaction zone where, by direct contact with relatively hot oil from said heating element, its'substantial vaporization is effected and the .antiknock value of said components of substantially motor fuel boiling range is materially-improved. Preferably a residual oil comprising the relatively heavy non-vaporous conversion productsof the systemand the relatively heavy components of the charging stock, remaining unvaporized, are withdrawn from the reduced pressure vaporizing zone of the system and a distillate of substantially motor fuel boiling range and of good antiknock quality comprising reformed straight-rungasoline and motor fuel resulting from the conversion of heav ier component -of the chargingstockis removed from the fractionator as the light distillate product of the system. 1

- Preferably at least a portion of the heat required,forwaporization-of the charging stock is recovered by indirect contact of the charging stock with relatively hot vaporous and/or liquid products of the system, prior to its introduction into the reaction zone.

The attached diagrammatic drawing illustrates one specific form of apparatus to which the principles of the process of. the invention tion chamber 5. Chamber 5 is also preferably maintained at a substantial super-atmospheric pressure and the materials remaining vaporized in this zone are subjected to continued conversion for a predetermined time While non-vaporous materials are quickly separated from the vapors, gravitating to the lower portion of the chamber to be removed therefrom, together with the slower moving vapors which have reached the exit, passing through line 6 and valve" 7 to vaporizing chamber 8.

vaporizing chamber 8 is preferably maintained at a substantially reduced pressure relative to that employed in chamber 5 by means of which, due to the liberation of latent heat,

. non-vaporous materials removed from chamber 5 are further vaporized and cooled. Oil remaining unvaporized in chamber 8 is removed therefrom as the residual product of the system through line 9 and valve 10 to cooling and storage or to any desired further treatment. Vaporous products from chamber 8 pass through line 11 and valve 12 to fractionator 24 where their insufficiently converted components are condensed, collecting as, reflux condensate in the lower portion of the fractionator to be Withdrawn therefrom through line 13 and valve 14 to pump 15 and supplied through line 16 and valvel'? to heating element 1 for further conversion.

Raw oil charging stock for the process, which comprises a hydrocarbon oil containing a sub: stantial proportion of components boiling within the range of motor fuel, is supplied through line 18 and valve 19 to pump 20 from which it is fed through line 21 and valve 22 to preheating coil 23. Preheating coil 23'is located Within fractionator 24, the charging stock passing therethrough receiving heat by indirect contact with the relatively hot vapors in this zone. The preheated raw oil passes through line 25 and valve 26 into reaction chamber 5, commingling therein with the heated on fromheating element 1 and being substantially vaporized. It will be understood that other well known means of preheating the raw oil charging stock may be employed in conjunction with or instead of the means illustrated. Such other means may comprise, for example, indirectly contacting the raw oil with residual oil fr'omfchamber 8 and/or with the material passing from chamber 5 to chamber 8. I

-;Relatively light vapors of the desired end boiling point, preferably falling within the boiling range of motor fuel and comprising both the motor fuel components of the charging stock, the antiknock value of which has been materially improved by subjection to the con version conditions in chamber 5, and cracked motor fuel resulting from conversion of the heavier components of the charging stock, are Withdrawn from fractionator 24 through line 27 and pass through valve 28 to condensation and cooling in condenser 29. Distillate and tincondensable gas passes from condenser 29 through line 30 and valve 31 to collection in receiver 32. Uncondensable gas is released from receiver 32 through line 33 and valve 34. Distillate is withdrawn from receiver 32 through line 35 and valve 36. A portion of the distillate may, if desired, be withdrawn from receiver 32 and recirculated, by well known means not shown in the drawing, to the upper portion of fractionator 24 to control the vapor outlet temperature and assist fractionation of the vapors in this zone.

Pressures employed within the system may range from substantially atmospheric to superatmospheric pressures as high as 2000 pounds per sq. in., or more. Conversion temperatures employed may range from 800 to 1200 F., more or less. Preferably conversion temperatures of the order of 900 to 1050" F. are employed in the heating element while somewhat milder conversion temperatures of the order of 750 to 950 F. are employed in the reaction chamber. Both the heating element and reaction chamber preferably utilize substantial super-atmospheric pressures of the order of 100 to 500 pounds or more per sq. in. The vaporizing zone and succeeding fractionating, condensing and collecting portions of the system preferably utilize substantially reduced pressures of the order of substantially atmospheric to 100 pounds per sq. in., or thereabouts. I

As a specific example of the operation of the process of the invention, a Mid-continent crude oil containing about 30 percent of gasoline having an antiknock value approximately equivalent to a blend of 20 percent benzol and percent straight-run Pennsylvania gasoline is the raw oil charging stock supplied to the system. The charging stock is preheated by the heat recovered within the cracking system and thence introduced into the reaction chamber. Reflux condensate from the fractionator of the system is subjected in the heating element to a tem foo iii.

perature of approximately 970 F. The stream of heated oil passing from the heating'element to the reaction chamber is cooled by the introduction of charging stock to a temperature of approximately 900 F. as it enters the reaction chamber. The heating element and reaction chamber are maintained under a super-atmosphericpressure of approximately 500 pounds per sq. in. The pressure in the vaporizing chamber is reduced to approximately 35 pounds per sq. in., which pressure is substantially equalized in the succeeding fractio'nating, condensing and collecting portions of the system.- This operation" may yield, based on the charging stock, approximately '75 percent of motor fuel having an antiknock value approximately equivalent to a blend of 60 percent benzol and40 percent straight-run Pennsylvania gasoline. Inaddition about 15 percent of good quality residual oil suitable for sale as fuel may be obtained, the

action zone maintained under cracking conditions of temperature and superatmospheric pressure, commingling crude oil containing natural gasoline, without prior heating thereof to cracking temperature, with the heated distillate being discharged into the upper portion of the reaction zone, passing the vaporous and liquid components of the thus commingled oils downwardly in unobstructed flow thru the reaction zone, removing the vapors and liquid oil as a mixture from the lower portion of the reaction zone, the liquid being Withdrawn at a rate adequate to prevent substantial accumula tion of liquid in the reaction zone, reducing the pressure on the mixture withdrawn from the reaction zone and separating the same into vapors and residue, dephlegmating the thus separated vapors to condense fractions thereof heavier than gasoline, supplying resultant reflux condensate to the heating zone as said hydrocarbon distillate, and finally condensing the dephlegmated vapors.

CHARLES H. ANGELL.

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