US2016339A - Treatment of hydrocarbon oils - Google Patents

Description

Oct. 8, .c MORRELL TREATMENT OF HYDROCARBON OILS Original Filed May 20, 1931 F RACTIONATOR PARTIAL CONDENSER,

coma SER 42 F RACTIONATOR FURNACE 29 INVENTOR JACQUE Q MORRELL Patented Oct. 8, 1935 2,016,339 TREATMENT OF HYDROCARBON OILS .iacquc C. Mon-ell, Chicago, Ill., assignor to Universal Oil Products Company, Chicago, 111., a corporation .of Delaware Continuation of application Serial No. 538,700, May 20, 1931'. This application December 3,

1934, Serial No. 755,782

4 Claims. (01. 196-50) This is a continuation of my co-pending application Serial Number 538,700, filed May 20, 1931.

This invention relates to the treatment of hydrocarbon oils and particularly refers to the conversion or reformation of relatively light distillates to improve their quality.

The primary concepts of the present invention comprise subjecting the relatively light distillate' such as gasoline or other light distillate containing a substantial proportion of materials boiling within the range of motor fuel to vaporization and fractionation to effect separation of the relatively light components of the distillate from the relatively heavy components of inferior quality, thence subjecting said relatively heavy components to conversion or reformation under conversion conditions controlled to improve their quality, particularly with reference to the boiling range and/or antiknock value of the finished product.

Many straight-run gasolines, for example, gasolines from Mu'skegon and Pennsylvania crudes are greatly inferior in antiknockquality to gasolines from other crudes, e. g., Midcontinent or California. Similarly cracked gasoline from some stock e. g., Muskegon may be inferior to cracked motor fuels obtained from other oils such as, for example, Pennsylvania, Midcontinent and California oils. Laboratory investigation has shown that the materials which promote knocking are often concentrated in the relatively heavy components of the motor fuel while the relatively light components may actually possess good antiknock qualities or at least are often of sufiiciently good quality in this respect, that they may be blended with gasoline of good antiknock value without endangering its .antiknock characteristics.

It has been proposed to subject gasoline or distillates containing gasoline of inferior antiknock quality to conditions of elevated temperature, and super-atmospheric pressure to produce version and. which may be of good antiknock quality as compared with the heavier components of the distillate.

In the specific embodiment of the inventio hereinafter illustrated and more fully described, 5

separation of the relatively light components of the distillate to be treated may be effected by heat recovered from the system in which said distillate is treated, said heat exchange not only serving the purpose mentioned but also serving to cool the stream of heated oil discharged from the heating element of the system to a temperature suificient to check too rapid conversion of the oil and prevent excessive gas and coke formation and at the same time serving to preheat the relatively heavy components of the distillate.

- Referring now to the attached diagrammatic drawing which illustrates one form of apparatus embodying the principles of the present invention, the oil to be treated, which may comprise straightmin or cracked gasoline of relatively low antiknock value or distillate containing gasoline or materials falling within the boiling range of gasoline, may be supplied through line I and valve 2 to pump 3 from which it may be fed through line 4, valve 5, heat exchanger 6, line I, valve 8 and line 9 into fractionator I0. Any desired portion of the distillate may be diverted from the heat exchanger and passed from line 4 through line 51, line II and valve I2, thereafter passing. all or in part either through valve I3, in line 9, to commingle with the heated distillate introduced into fractionator I0 or passing through valve I4, in line I2, into the upper portion of the fractionator, serving as a cooling medium to assist fractionation of the vapors.

The temperature to which the distillate is heated in heat exchanger 6 is.preferably sufficient to effect its substantial vaporization or at least vaporization of substantially all the relatively light components which it is desired to separate therefrom. Any desired type of fractionating means such as bubble trays, perforated pans, packing or the like, not illustrated, may be provided in fractionator I0. Fractionated vapors may leave the fractionator through line I5 fractionator of the conversion system and collected therewith as will be more fully described later or, if desired, these relatively light vapors may be separately condensed, cooled and collected by well known means, not illustrated in the drawing. I p

The relatively heavy components of the distillate which are not vaporized as well as those which are condensed in the fractionator collect within the lower portion of this zone and may be withdrawn through line l9 and valve 20 to pump 2| from which they-may be fed through line 22, valve 23, line 24 and valve 25 into heating element -26. If desired, a portion of said relatively heavy components of' the distillate may be diverted from line 22. through line 21 and valve 28 to commingle in line 4 with the distillate supplied to heating element 6. In this manner and/or by diverting a portion of the distillate from the heat exchanger through line H, as already described, both the temperature of the distillate entering fractionator l0 and the temperature to which the oil discharged from heating element 26 is cooled in heat exchanger 6 may be controlled. A portion of the charging stock may, if desired, be passed directly into heating element 26 by diverting it from line 4 through line 51 and valve 58 and thence through line 24 to the heating element.

Heat may be supplied to heating element 26 by means of any suitable form of furnace 29 and the oil passing through this zone may be heated to the desired conversion temperature preferably under a substantial super-atmospheric pressure although substantially atmospheric or relatively low super-atmospheric pressures may be employed, if desired. The heated oil may be discharged from heating element 26 through line 30 and valve 3|, into heat exchanger 6 wherein it is preferably cooled, as already described, sufficiently to prevent excessive coke or gas formation, discharging thereafter through line 32 and valve 33 into the lower portion of fractionator 34. A drain line 55 controlled by valve 56 may,

be provided on heat exchanger 6 to permit removal from this zone of any heavy pitch-like or free-carbon containing residual products of the conversion which may separate from the lighter conversion products.

If substantial super-atmospheric pressure is employed in heating element 26 it is preferably substantially reduced'before the oil enters the lower portion of fractionator 34 or, if desired, before the oil enters heat exchanger 6 for the purpose of assisting in cooling the reaction v products and to effect their substantial vaporization in the lower portion of the fractionator.

The lower portion of fractionator 34 preferably comprises a zone in which substantial vaporization of the conversion products may be effected. Conversion may or may not continue in this zone, depending upon the temperature to which the heated products are cooled by the pressure reduction and by heat exchange with. the charging stock as well as upon the pressure employed in this zone. If conversion conditions are employed in the lower portion of fractionator 34 they are preferably of a sufliciently mild nature to preclude any substantial coke formation and to inhibit the productionofexcessive quantities of uncondensable gas.

Any desired type of fractionating means, not illustrated, may be provided in fractionator34 such as, for example, bubble trays, perforated pans or packing, to effect separation of the relatively light desirable components of the vapors from the relatively heavy insufliciently converted components which latter may be condensed in the. fractionator and may collect in the lower portion thereof to be withdrawn, together with non-vaporous reaction products, through line 35 and valve 36 to pump 31, from which this oil may be supplied through line 24 and valve 25 to heating element 26, for further conversion, together with the relatively heavy components of the distillate charging stock from fractionator l0, introduced into line 24 as already described.

The relatively light desirable components of the vapors which preferably are of such boiling range that when blended with the vapors from fractionator II) the products will be substantially of motor fuel boiling range, may be withdrawn from may pass alone or together with vapors from fractionator III, as desired, through line 40 and valve 4| to condenser 42 wherein they may be subjected to condensation and cooling, passing thereafter asdistillate and gas through line 43 and valve 44 to be collected in receiver 45. Uncondensable gas may be released from receiver 45 through line 46 and valve 41 while distillate may be withdrawn from this zone through line 48 and valve 49. A portion of the distillate may, if desired, be withdrawn from receiver 45 through line 50 and valve 5| to be recirculated by means of pump 52 through line 53 and valve 54 to the upis from 900 to 1050 F. or thereabouts and, generally speaking, with relatively high conversion temperatures relatively low pressures of the order of substantially atmospheric to 100 pounds per square inch super-atmospheric pressure are preferably employed while with the lower conversion temperatures of the order of 900 to 975 F. or thereabouts, higher super-atmospheric pressures of the order of 100 to-500 pounds per square inch, more or less, may be utilized. V

As a specific example of the operation of the process of the present invention as it may be practiced in an apparatus such as illustrated and above described, a straight-run Pennsylvania distillate having an initial boiling point of approximately F. and an end boiling point of approximately 580 F. and having a sub-zero antiknock rating on the benzol scale, is preheated in the manner illustrated in the drawing and the components boiling between approximately 90 and 200 F. are separated by fractionation and subsequently condensed, cooled and collected together with the distillate from the cracking opintroduction into the lower portion of the fractionator.

This operation may yield approximately 92 per cent of premium motor fuel having an antiknock value equivalent to a .blend of approximately 55 per cent benzol and 45 per cent straight-run Pennsylvania gasoline of zero antiknock rating.

I claim as my invention:

1. A process for improving light petroleum distillate containing motor fuel boiling hydrocarbons which comprises heating a portion of the distillate charging stock to distillation temperature by heat exchange with a heating medium, subsequently fractionating this portion of the distillate in contact with another portion of the charging stock and separating the contacting portions into a light gasoline fraction and a heavier fraction containing gasoline hydrocarbons, heating the heavier fraction to a temperature in excess of 850 F. to

reform the same by thermal conversion, utilizing the thus heated heavier fraction as said heating medium and then fractionating and condensing the vapors thereof.

2. A process for improvingilight petroleum distillate containing motor fuel boiling hydrocarbons which comprises heating a portion of the distillate charging stock to distillation temperature by heat exchange with a heating medium, subsequently fractionating this portion of distillate in contact with another portion of the charging stock and separating the contacting portions intoalight gasoline fraction and a heavier fraction containing gasoline hydrocarbons, heating the heavier fraction to a temperature in excess of 850 F. to reform the same by thermal conversion, utilizing the thus heated heavier fraction as said heating medium and then separating therefrom the desired gasoline hydrocarbons of increased antiknock value, and blending the latter with said light gasoline fraction.

3. A process for improving light petroleum distillate containing motor fuel boiling hydrocarbons which comprises heating a portion of the distillate to distillation temperature in a zone of heat exchange, then introducing such heated distillate and another portion of the raw distillate to a fractionating zone for fractionation therein, separating said portions of the distillate into a light vaporous gasoline fraction and a heavier liquid fraction containing gasoline hydrocarbons, 5

passing the heavier liquid fraction through aheating zone and heating the same to a temperature in excess of 850 F. to reform the same by thermal conversion, then passing the heavier fraction through said zone of heat exchange in indirect heat exchanging relation with the first-named portion of the distillate therein to supply heat to the latter, then introducing the heavier fraction to a second fractionatlng zone and separating the desired reformed hydrocarbons as vapor from the heavier hydrocarbons as liquid; and finally condensing the vapors uncondensed in said fractionating zones.

4. A process for improving light petroleum distillate containing motor fuel boiling hydrocarbons which comprises heating a portion of the distillate to distillation temperature in a zone of heat exchange, then introducing such heated distillate and another portion of the raw distillate to a fractionating zone for fractionation therein, separating said portions of the distillate into a light vaporou's gasoline fraction and a heavier liquid fraction containing gasoline hydrocarbons, passing the heavier liquid fraction through a heating zone and heating the same to a temperature in excess of 850 F. to reform the same by thermal conversion, then passing the heavier fraction through said zone of heat exchange in indirect heat exchanging relation with the first-named portion of the distillate therein to supply heat to the latter, then introducing the heavier fraction to a second fractionating zone and separating the desired reformed hydrocarbons as vapor from the heavier hydrocarbons as liquid, combining the vapors uncondensed in the second fractionating zone with the vaporous light fraction from the firstmentioned fractionating zone, and finally condensing the thus commingled vapors.

JACQUE C. MORRELL.

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