US2059290A - Conversion of hydrocarbon oils - Google Patents

Description

1 K. SWARTWOOD 2,059,290 Y I CONVERSION OF HYDROCARBON OILS v Original Filed Dot. 2e, 1953 FRACTIONATOR CONDENSER FURNACE TOPPING AND FRACTIONATING VAPOR IZ INC AND TING FURNACE 2o FURNACE RECEIVER hydrocarbon oils of Patented Nov. 3, 1936 PATEN T F F11 CE 2,059,290 CONVERSION OF HYDROCARBON OILS Kenneth Swartwood, Chicago, 111., Universal Oil Products Company,

assignor to Chicago, 111.,

a corporation of Delaware Application October 26, 1933, Serial No. 695,268

enewed 7 Claims.

This invention relates to and apparatus for an improved process the fractional distillation of relatively wide boiling range, such as crude petroleum, accompanied by pyrolytic conversion of all but the desirable low-boiling fractions of the charging stock and further conversion of the insufficiently converted intermediate products of the process to produce high yields of desirable low-boiling distillate, such as motor fuel of high antiknock value, and good quality fuel oil residue.

One specific embodiment of the present invention comprises subjecting hydrocarbon oil, such as crude petroleum, to fractional distillation, recovering its desirable low-boiling fractions, subjecting its intermediate fractions to conversion temperature at superatmospheric pressure in a heating coil, introducing the resulting products into a reduced pressure vaporizing chamber, subjecting bottoms from the topping operation to conversion temperature at superatmospheric pressure in a separate heating coil, subjecting the resulting products to vaporization and fractionation, subjecting fractionated vapors of the desired endboiling point to condensation and collecting the resulting products, returning low-boiling components of the reflux condensate produced by said fractionation to the first mentioned heating coil for further conversion, supplying bottoms from said fractionation'and vaporizing stage to said reduced pressure vaporizing chamber, subjecting vaporous products from the vaporizing chamber to fractionation, subjecting fractionated vapors of the desired end-boiling point to condensation and collecting the resulting products, subjecting reflux condensate resulting from the'last vmentioned fractionating stage to conversion temperature at superatmospheric pressure in another separate heating coil and, if desired, a communicating reaction chamber and introducing the resulting vaporous and liquid conversion products into said reduced pressure vaporizing chamber.

One of the features of the invention is the provision for subjecting the bottoms from the topping operation (high-boiling fractions of the charging stock) to a mild cracking or viscosity breaking operation in a single pass through a heating coil and subjecting the resulting residual conversion products to further vaporization for 'the production of good quality fuel oil.

Another advantageous feature of the invention resides in the provision for subjecting intermediate fractions of the charging stock, resulting from the topping operation, to conversion, to-

March 18, 1935 gether with corresponding intermediate fractions resulting from the relatively mild oncethrough conversion of the high-boiling fractions of the charging stock, to conversion under independently controlled conditions in a single pass through a separate heating coil.

Another feature of the invention provides for cooling the hot conversion products from the heating coil to which the intermediate fractions of the charging stock .and intermediate con- 10 version products from the first or relatively mild cracking stage of the process are supplied to a temperature at whichtheir excessive conversion is prevented, by commingling therewith highboiling conversion products resulting from the first cracking stage of the process whereby to heat the latter sufficiently to effect their mild continued conversion and substantial further vaporization.

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

, Referring in detail to the drawing, raw oil charging stock for the process, preferably comprising an oil of relatively wide boiling range, such as crude petroleum, for example, is heated to a temperature suflicient to effect its substantial vaporization by a well known means, not illustrated in the drawing, and is supplied in heated state through line i and valve 2 to topping and fractionating column 3, wherein it may be separated into low-boiling, high-boiling and intermediate fractions.

Any desired low-boiling fractions of the charging stock, comprising, for example, gasoline or light gasoline fractions of satisfactory antiknock value, may be withdrawn from the upper portion of column 3 through line 4 and valve 5 to condenser 6, wherein they are subjected to condensation and cooling. The resulting distillate and gas passes through line 1 and valve '8 to collection and separation in receiver 9. Uncondensable gas may be released from the receiver through line iii and valve ll. Distillate may be withdrawn from this zone through line l2 and valve I3 to storage or to any desired further treatment. If desired, a regulated portion of the distillate collected in receiver 9 may be recirculated by well known means, not shown in the drawing, to the upper portion of column 3 to and fractionation of the vapors in this zone and to maintain the desired vapor outlet temperature from the column, thus regulating the end-boiling point of the overhead distillate prodnot.

antiknock value boiling fractions toms, light gas oil and t from any suitable inter Intermediate fractions of the charging stock, comprising, for example, any gasoline or highand valve (5 to pump l8 by means of which this material is supplied through line I! and valve H! to conversion in heating coil l9.

discharged through line 2! and valve 22 into vaporizing chamber 23. Prefeably the stream of tially reduced pressure relative to that employed including its components boillng above the range densable gas may be released from the receiver through line 40 and valve 4|. Distillate may be withdrawn from receiver 39 through line 42 and densate, comprising, for example, any motor fuel or high-boiling motor fuel fractions of inferior as well as, when desi pressure distillate bothe like, are withdrawn mediate point or points ple, through line 44 and in vaporizing cha mingled oils from ously described.

2| are supplied as previulting distillate a and valve 63 cooling. The res through line 62 separation in receiver 64. may be releas and valve 68.

nd gas passes to collection and Uncondensable gas ver 64 through line may be withdrawn ed from recei regulating the enddistillate product f Components of t to fractionator 58,

rom this zone.

which is withdraw fractionator ower portion of the and valve "I0 to he reflux condenthrough line 72 and wherein it is subjected 75 through line 69 Pump "H supplies t fractionator 58 valve 13 to heating coil M,

. let from the. heating coil to ,fractions of the charging sure, measured. at this point in the system,

i and ber 19 through line they pass through line 80 and line 2| into vaporu topping. and fractionating equipment.

ably. a conversion to further conversion,preferably-at superatrnospheric pressure, by means of heat supplied from a furnace -15 of anysuit-able form. -Thehot conversion products are dischargedfrom heating-coil 74 through line 16 andmay pass,-al1 or'inpart, either through line "l1 and valve -l'Binto reaction chamber 19 or through line 80, valve at and line i2l directto vaporizing chamber 23.

Reaction chamber '19, when utilized, is preferably operated at' a superatmospheric pressure, -which maybe substantially equalized with that maintainedat the outlet from heating coil 14 or may be somewhat reduced. Although not illustrated, chamber 19 is also preferably well insulated to prevent the excessive loss of heat from this zone. by radiation so that conversion of the products supplied thereto from heating coil 14,

more particularly their vaporous components, may continue in the reaction chamber In the casehere illustrated, both vaporous and liqnid. conversion products are'withdrawn'in commingled state fromthelower portion of cham- 82 and valve 83, from which izing chamber 23,.together with the commingled products from heating coil l9 and from the lower portion of column 33.

Any desired pressure'ranging'from' substantially atmospheric or subatmospheric to a superatmospheric pressure of 200 pounds, or more,

I per square inch, may be employed for the frac- .erably within the rangeof 300 to 1000 pounds,

- or, thereabouts, per square inch, although, when ,.desired, lower pressures i to 950 F.,.orthereabouts,

down to substantially atmospheric may be employed in this zone. A conversion temperature within the range .of 800 is preferably employed at the outlet from the heating coil to which highboiling fractions of the charging stock are supplied and preferably a superatmospheric pressure of from 100 to 500 pounds, or thereabouts, per square inch,.is employed at this point in the systemand may be either substantially equalized or reduced in the succeeding vaporizing and fracv tionating column. The heating coil of the last conversion stage of the process, to which only reflux condensate from the. same stage is returned for further conversion, may utilize an outfor example, of from 850 to 950 F., or thereabouts, preferably with .asuperatmospherio pressure, measured at the outlet; from the heating coil, of the orderof 100 to 500, pounds, or more, per square inch.

. As already mentioned, substantially .the same or somewhat reduced superatmospheric pressure may be utilized in the succeeding reaction chamber, when such a zone is employed, and a substantially reduced pressure ranging, for example, from 100 pounds, or thereabouts, per square inch .to substantially atmospheric is preferred in the vaporizing chamber. Substantially equalized or somewhat reduced pressures, relative to that employed in the vaporizing chamber,..may be utilized in the succeeding fractionating, condensing and collecting portions of the system.

of the last mentioned cracking stage.

mediate fractions from this stage of the process, boiling between approximately 350 to 550 F. are returned to the heating coil of the first square inch. Vapors from the vaporizing As a specific-example of one 'of the many possible operations of the process of the present invention as it may be practiced in an apparatus such as illustrated and above described: :the charging stock is anOklahoma crude of about it 50 A. P.'- I. gravity, containing about 50 percent of material boiling up to 400 but of poor anti-knock value,-and the charging stock is subjected to fractional distillationwhereby about 2'7 percent of light gasoline fractionslilO having an end-boiling point of about 250 F. and of good antikno'ck value are recovered. Intermediate fractions of the charging stock, boiling between aproximately 250 and 550 F. and comprising about 43 percent of the crude, are subjected to a conversion temperature of approximately 980 F. at a superatmospheric pressure of (about 800 pounds per square inch. The remainder of the charging stock, comprising its high-boiling fractions, are separately subjected to a conversion temperature of about 920 F. at a superatmospheric pressure of about 300 pounds per square inch. A motor fuel of about 350 F. end-boiling point and of good antiknock value is recovered as the light distillate product-'= Intermentioned cracking stage; for further conversio together with said intermediate fractions of the charging stock. The higher boilingconversion products from the last mentioned cracking stage are commingled with the highly heated prod: note from the heating coil of the'first cracking stage and the commingled oils are introduced into a vaporizing chamber operated at-a superatmospheric pressure of about-75 pounds per chamber are subjected to fractionation whereby 211 motor fuel of about 400 F. end-boiling point and of good antiknock value is recovered as the overheaddistillate product and reflux condensate from the fractionator is subjected to further conversion ata temperature of about 950 F. and a superatmospheric pressure ofapproximately 400 pounds per square inch and the resulting vaporous andliquid conversion products are introduced into" the vaporizing chamber.

-An operation such as above described may yieldyper barrel of charging stock, about "70 percent of -motor fuel having an antiknock value equivalent to an octane number of approximately '72 and about '20 percent of good quality fuel oil residue, the remaining 10 percent, or there-" abouts, being chargeable, principally, to uncondensable gas and loss.

I claim asmy invention:

1. In a process for the conversion of hydrocarbon oils wherein raw oil charging stock for the process is subjected to fractional distillation to separate it into desirable low-boiling components, which are condensed, intermediate components .and high-boiling components, the intermediate components subjected to pyrolytic-' conversion at elevated temperature and super- .atmospheric pressure, the high-boiling components subjected to pyrolytic conversion under relatively less severe conditions of elevated temperature and superatmospheric pressure and the products resulting from said pyrolytic conversion of the high-boiling components subjected to vaporization and fractionation whereby they are separated into desirable low-boiling products, which are condensed, insuiiiciently converted'in-" jecting a hydrocarbon distillate to cracking conditions of temperature and pressure in a heating coil and subsequently discharging the same into a reduced pressure vaporizing chamber, simultaneously subjecting a topped crude oil in a second heating coil to a relatively mild cracking treatment of a viscosity reducing character and subjecting the resultant products to vaporization and fractionation independently of the heated products from the first-named coil, supplying bottoms and reflux condensate from this vaporization and fractionation stage to said chamber and first-named coil respectively, separating vapors from unvaporized oil in said chamber and withdrawing the unvaporized oil from the process, fractionating the vapors to condense heavier fractions thereof and subjecting resultant reflux condensate to independently controlled cracking conditions of temperature and pressure in a third heating coil maintained at higher temperature than said second coil, introducing conversion products of the last named reflux condensate into said chamber, and finally condensing the fractionated vapors.

6. A conversion process which comprises subjecting a straight run hydrocarbon distillate to cracking conditions of temperature and pressure in a heating coil and subsequently discharging the same into a reduced pressure vaporizing chamber, simultaneously subjecting a topped crude oil in a second heating coil to a relatively mild cracking treatment of a viscosity reducing character and subjecting the resultant products tovaporization and fractionation independently of the heated products from the first-named coil, passing bottoms from this vaporization and fractionation stage to said chamber, supplying reflux condensate from said stage to the firstnamed coil for cracking treatment therein together with said straight run distillate, separating vapors from unvapo-rized oil in said chamber and withdrawing the unvaporized oil from the process, fractionating the vapors to condense heavier fractions thereof and subjecting resultant reflux condensate to independently controlled cracking conditions of temperature and pressure in a third heating coil, introducing conversion products of the last-named reflux condensate into said chamber, and finally condensing the fractionated vapors.

'7. The process as defined in claim 6 further characterized in that said straight run distillate contains hydrocarbons boiling within the gasoline range and is subjected in the first-named coil to higher cracking temperature than the lastnamed reflux condensate in the third coil.

KENNETH SWARTWOOD.

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