US1980215A - Treatment of hydrocarbon oil - Google Patents

Description

Nov. 13, 1934. w, H. McADAMs E1- AL,

TREATMENT OF HYDROCARBON OIL FiledA April 19. 1932 Patented Nov. 13, 1934 TREATMENT or nnmocAaBoN on.

William H. McAdams, Newton, and Harold IC. Weber, Milton, Mass., assignors to Universal 0i1 Products Company, Chicago, Ill., a corporation of South Dakota Application April 19, 1932, Serial No. 606,180

6 Claims.

'Ihis invention relates to the treatment of hydrocarbon oils, and more particularly refers to an improved process and apparatus for the conversion of relatively heavy oils or oils of inferior quality to produce substantial yields of a desirable light product stabilized with respect to its boiling point and vapor pressure.

The present invention provides an improved method and means of producing a stabilized distillate product direct from the cracking system and in its primary principles comprises an improved methodv and means of stabilizing the distillate vapors within the cracking system prior to their nal condensation, utilizing to best advantage heat stored within said vapors and the operating pressure of the system to assist said stabilization.

A special feature of the invention comprises the use of a portion of the gaseous conversion products such as propane, butane, pentane, etc., as cooling means within the upper portion of the stabilizer by cooling and condensing a portion of said gaseous products, separating and withdrawing the uncondensed fractions, and returning the condensate, at least in part, to the top of the stabilizer.

Another feature of the invention comprises the use of relatively hot vaporous conversion products from the reaction zone of the cracking system as a means of reboiling distillate collected in the lower portion of the stabilizer and subsequently withdrawn therefrom as the stabilized distillate product of the process. This is accomplished by indirect contact and heat exchange nents of the vapors, returning said insufciently converted materials as reflux condensate from the fractionator to the heating element for further conversion, subjecting vaporous products from the fractionator comprising materials of substantially motor fuel boiling range and gases to further fractionation in a stabilizer preferably maintained at a substantial superatmospheric pressure, from the gases and vapors generated within the cracking system collecting, as condensate ,in the lower portion of the stabilizer, the motor fuel product of the system and reboiling this condensate to substantially free the motor fuel of gases and uncondensable lightA ends by indirect contact and heat exchange between this material and vaporous products of the system passing from the reaction chamber to the fractionator,

cooling and collecting the stabilized motor fuely subjecting them to cooling and collection, there* after returning all or a portion of the condensate to the upper portion of the stabilizer to serve as a cooling means to assist stabilization in this zone,

and withdrawing the uncondensed gases from theV system.

It will be understood that while the foregoing description has referred specifically to the production of stabilized motor fuel the principles of the invention are equally applicable to the production of any desired cracked product in stabilized form.

The attached diagrammatic drawing illustrates one specific form of apparatus embodying the principles of the present invention. The following description of the drawing includes the description of the process of the invention as it may be practiced in the apparatus illustrated.

Raw il charging stock for the system may be supplied through line 1 and valve 2 to pump 3 from which it is fed through line 4 and may pass through line 5, valve 6 and valve 7 into heating element 8. All, or any portion of the raw oil may be preheated, if desired, prior to its introduction to the heating element, by any well known means, for example, all or any portion of the raw oil may pass from line 4 through line 9 and valve 10 into fractionator 11 wherein it is preheated by direct contact with the relatively hot vapors in this zone, assisting their fractionation and passing together with their relatively heavy components, which are condensed in the fractionator, through line 12 and valve 13 to pump 14. Pump 14 supplies the reflux condensate or reflux condensate and preheatedl raw oil from fractionator 11 through line l5 and valve 16 into line 5, and thence through valve 'I to heating element 8.

Furnace 17 of any suitable form supplies to the oil passing through heating element 8, the heat required for its conversion under the desired pressure conditions employed in this zone. The heated oil passes from heating element 8 through line 18 and valve 19finto reaction chamber 20 which, like heating element 8, is preferably maintained at a substantial superatmospheric pressure. The inlet and outlet connections to chamber 20 are preferably such that conversion, particularly of the vapors, may continue for a predetermined time in this zone while the liquid conversion produ cts are qujclgly separated from the vapors and means of maintaining this condition in chamber 20 may be employed, for example, as illustrated in the drawing the heated materials from heating element 8 may enter the upper portion lof chamber 20, passing downward-through this zone from the lower portion of which residual oil isremoved through line 21 and valve 22 while vaporous products pass upward through the extended vapor line 13 to be withdrawn through line 24 to fractiona- .Vapors from chamber 20 are withdrawn through line 24 and valve 25 to fractionator 11, a portion thereof preferably passing through line 26, valve 26 and closed coil 28 in the lower portion of stabilizer 27, for the purpose of reboiling the distillate f collected in' the lower portion of this zone as will be later more fully described, thence passing through line 30, valve 31 and line 24 to fractionation in fractionator 11.

Residual oil from chamber 20 withdrawn, as described, through line 21 and valve 22 preferably passes to further vaporization in flash distilling and valve 60. Vapors from chamber 29 may pass to separate fractionation, condensation, cooling and collection throughlines 32, 32 and valve 33' (valve 33 being closed), condenser 69, line 70 and valve 71 to vented receiver 61 and through line 64, valve Y65 and line 66 to pump 3, a part of the distillate if desired, being drawn off through line 68 and valve 67; or the vapors may pass through line 32, valve 33, pump or compressor 34, line 35 andvalve 36 to fractionatiomin fractionator 11 together with material from chamber 20 introduced into this zone, as already described.

Pump or compressor 34 need be employed only in case the pressure in chamber 29 does not exceed that in fractionator 11.

Vapors introduced into fractionator 11, as described, are separated by fractionation into relatively light components comprising vapors of substantially motor fuel boiling range and gas and heavier components which are condensed in the fractionator to be returned therefrom, as already described, toheating element 8 for further conversion.

Vapors and gases from fractionator 11 pass through line 37 and valve 38 to further fractionation or stabilization in stabilizer 27. Vapors of substantially motor .fuel boiling range are condensed in this zone, collecting in the lower portion thereof, wherein they may be reboiled for the purpose of substantially freeing them from vapors of excessive volatility and uncondensable light ends by means of heat imparted thereto from the vapors passing through coil 28 as already described. The stabilized distillate product of the system is withdrawn from the lower portion of stabilizer 27 through line 39 and valve 40, passing through cooler 41 to storage or to any desired further treatment through line 42 and valve 43.

Gaseous products and vapors are withdrawn from stabilizer 27 through line 44 and valve 45 to be subjected to cooling and partial condensation in coil 46, thereafter passing through line 47 and valve 48 to collection in receiver 49. This cooling andcollection is preferably effected under sub-V stantially the same pressure as that employed in the stabilizer, and depending upon vthe degree of cooling employed in coil 46, a separate portion of the gaseous products being collected as condensate in receiver 49.

'I'he cooled and uncondensed gases are released from receiver 49 through line 50 and valve 51. A portion of the distillate collected in receiver 49 may be released from the receiver through line 52 and valve 53, the remainder or all being withdrawn through line 54 and valve 55 to pump 56 by means of which the condensate is returned through line 57 and valve 58 to the upper portion of stabilizer 27, where itoserves as a means for cooling and assisting fractionation in the upper portion of the stabilizer. If desired, any well known means of cooling or refrigerating in the upper portion of stabilizer 27 may be employed in conjunction with the method illustrated in the drawing. A part or all of the raw oil maygif desired, be preheated to 700-800" F. and fed directly to flash chamber 29, instead of to fractionator 11 or coil 8 as shown in the drawing. 'I'his alternative is desired when handling topped crudes.

superatmospheric pressures are employed within the system preferably from several hundred pounds per square inch to as high as 1000 pounds or more per square inch. Conversion temperatures employed may range from 800 to 1100 F. The heating element is preferably maintained at va substantially superatmospheric pressure of the order of to 1000 pounds per square inch. Substantially the same range loi' pressures may be employed in the reaction chamber while the fractionating, stabilizing, cooling and collecting portions of the system may be maintained at substantially the same or a somewhat lower pressure than that employed in the reaction chamber, substantial superatmospheric pressures of f the order of 100 pounds or more, per square inch preferably being employed in the stabilizer. The residuum flash distilling chamber 29 is preferably maintained'at a substantially reduced pressure relative to that employed in the reaction chamber ranging, for example, from substantial atmospheric to 100 pounds per square inch, or thereabouts. f

As a specific example of the operation of the process of the present invention, a 42 A. P. I. gravity Pennsylvania distillate is the charging stock supplied to the system which is subjected, together with reflux condensate from lthe system, to a temperature of approximately 910 F. at

the outlet from the heating element. A superatmospheric pressure of approximately 380 pounds per square inch is employed in the heating element and is substantially equalized in the reaction chamber. The fractionating, stabilizing, cooling and collecting portions of the system are maintained at approximately 150 pounds per square inch.A Stabilized distillate is withdrawn from the lower portion of the stabilizer at a temperature of approximately 310 F., and is subsequently cooled to approximately atmospheric temperature. A temperature of about 120 F. is maintained in the upper portion of the stabilizer. Residual oil from the reaction chamber is subjected to iiash distillation at a reduced pressure of about 35 pounds per square inch, and the resulting vapors are subjected to condensation, the condensate being continuously recharged to the system. This operation may result in the production of a motor fuel product amounting to approximately 76% charging stock having an antiknock value approximately equivalentto a blend of 'I5-80% iso-octane and 25-20% normal heptane. 'Ihe motor fuel has an initial boiling point of approximately 100 F., an end boiling point of approximately 400 F., and is substantially free of iso-butane, propane and lighter gases, but contains a suflicient amount of butane to give it easy starting characteristics. The additional products Aof the system may comprise about 10% of residual oil based on the charging stock and a' rich noncondensable gas.

We claim as our invention:

1. .A process which comprises subjecting hydrocarbon oil to cracking conditions of temperature and pressure and separating the same into vapors and residue, dividing such separated vapors into two portions, introducing one of the portions into a fractionating zone and fractionating the same therein to condense fractions thereof heavier than gasoline, passing the fractionated vapors to a stabilizing zone and condensing and stabilizing the gasoline therein, the gasoline condensate being collected in the lwer portion of the stabilizing zone and withdrawn therefrom as a product of the process, and passing the other portion of the separatedl vapors, prior to any substantial cooling and condensation thereof, in indirect heat exchange with the gasoline condensate in the lower portion of the stabilizing zone.

2. A process which comprises subjecting hydrocarbon oil to cracking condition of temperature and pressure and separating the same into vapors and residue, dividing such separated vapors into two portions, introducing one of the portions into a fractionating zone and fractionating the same therein to condense fractions thereof heavier than gasoline, passing the fractionated vapors to a stabilizing zone and condensing and stabilizing the gasoline therein, the gasoline condensate beingv collected in the lower portion of the stabilizing zone and withdrawn therefrom as a product of the process, and passing the other portion of the separated vapors, prior to any substantial cooling and condensation thereof, in indirect heat exchange with the.gasoline condensate in the lower portion of the stabilizing zone and subsequently introducing the same to the fractionating zone for fractionation and subsequent stabilization in admixture with lthe rstmentioned por` tion of the vapors.

3. A process which comprises subjecting hydrocarbon oil to cracking temperature in a cracking zone maintained under pressure thereby forming vapors and unvaporized oil, removing the vapors and unvaporized oil from the cracking zone and flash distillingthe latter by pressure reduction, passing the resultant flashed vapors and the vapors formed in the cracking zone to a fractionating zone` and fractionating the commingled vapors therein to condense fractions thereof heavier than gasoline, supplying the fractionated vapors to a stabilizing zone and condensing and stabilizing the gasoline therein thereby forming gasoline condensate in the lower portion of the stabilizing zone, and passing at least a portion of the first-mentioned vapors, while in transit from the cracking zone to the fractionating zone, in indirect heat exchange with the gasoline condensate in the lower portion of the stabilizing zone.

4. In a process for the cracking of relatively higher boiling hydrocarbons into lower boiling hydrocarbons to produce a stabilized motor fuel, with respect to its vapor pressure, of the character wherein the oil is heated to conversion conditions of temperature and pressure in a. heating coil, the products therefrom being discharged into a reaction chamber, the improvement which comprises separating the vapors and non-vaporous residue in the said reaction chamber, introducing the non-vaporous residue into a zone of reduced pressure wherein a further separation of vapors and non-vaporous residue occurs, removing the non-vaporous residue from the system, compressing the `vapors leaving the zone of reduced pressure and introducing the same into a fractionator, removing the reflux condensate from the fractionator and returning the same -to the heating coil for further conversion, removing the vapors from the fractionator and introducing the same into a stabilizer without substantial decrease in pressure, introducing into the upper portion of the stabilizer a cooling agent comprising the cool and condensed low boiling liquid overhead products removed from the stabilizer, simultaneously subjecting liquid condensed within the stabilizer to indirect heat exchange with a portion of the vapors leaving the reaction chamber, the remaining vapors from the reaction chamber being passed to the fractionator, thus heating the liquid within the stabilizer and causing the removal therefrom of low boiling and gaseous components,

and stabilizing the remaining liquid, withdrawing to the cracking step for retreatment, passing the fractionated vapors to a stabilizing zone and condensing and stabilizing the gasoline therein, the gasoline condensate being collected in the lower portion of the stabilizing zone and withdrawn therefrom as a product of the process, passing the other portion of the separated vapors in indirect heat exchangewith the gasoline condensate in the lower portion of the stabilizing zone and subsequently introducing the same to the fractionating zonefor fractionation and subsequent stabilization in adrnixture with the first-mentioned portion of the vapors.

6. A process which comprises subjecting hydrocarbon oil to cracking temperature in a cracking zone'maintained under pressure and separating the same therein into vapors and unvaporized oil, passing the separated vapors to a fractionating zone, flash distilling the unvaporized oil by pressure reduction and introducing the resultant flashed vapors to the fractionating zone for admixture with the rst-mentioned vapors, fractionating the commingled vapors in the fractionating zone to condense fractions thereof heavier than gasoline and returning resultant reilux to Vthe cracking zone for retreatment, supplying the

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