Патент USA US2118605код для вставки
May 24, 1938. . ' 2,118,605 L. c. HUFF PROCESS FOR CRACKING HYDROCARBONOILS Original Filed Nov. 13, 1950 KOL-(EUMATQ Emi-LU Mm Ir: 1|l ZEDJOU MOIEUHR m-il. ‘ mm FIlH| / h INVENTOR LYMAN C. HUFF ATTORNEY Patented May 24, 1938 2,118,605 UNITED STATES PATENT OFFlCE 2,118,605 PROCESS FOR CRASIIEISNG HYDROC‘ARBON Lyman O. Huff, Chicago, 111., assignor, by mesne assignments, to Universal Oil Products Com pany, Chicago, 111., a corporation of Delaware Application November 13, 1930-, Serial No. 495,394 Renewed November 2, 1934 1 Claim. (Cl. 196-48) This invention relates to the cracking or ther mal decomposition of hydrocarbon oils, and more particularly refers to the treatment of relatively heavy hydrocarbon oils under cracking condi 5 tions to produce maximum quantities of more from the secondary fractionating column of the primary or relatively low temperature cracking system. Oil of this character may, for exam ple, be obtained from another cracking system valuable products. Primarily, the present invention comprises sub using a secondary dephlegmator, or from the re- 5 distillation of pressure distillate. A portion of this same oil, or similar product, may, if desired, jecting intermediate products from a liquid-vapor phase or relatively low temperature cracking sys be fed directly into the heating element of the vapor phase or relatively high temperature crack 10 tem to reconversion in a vapor phase or rela— ing system, thereby increasing the total charge 10 tively high temperature cracking system and re turning intermediate products from said rela tively high temperature system to the heating ele ment of the relatively low temperature system fed to the system. This oil may also be employed to assist fractionation of the vapors in the de phlegmator of the secondary or vapor phase sys tem. for reconversion. In its speci?c embodiment, the process of the invention comprises subjecting an oil to liquid vapor phase or relatively low temperature crack ing conditions in a primary heating element, in troducing the heated materials into an enlarged reaction zone, subjecting vapors from said reac~ tion zone to fractionation in a primary dephleg The accompanying drawing illustrates dia- 15 grammatically, and not to scale, one speci?c form which‘ the apparatus of the present inven mator, from which the heavier portion of the vapors is returned as re?ux condensate to the primary heating element for reconversion, and light uncondensed vapors from which are sub jected to further fractionation in the secondary fractionating column, subjecting the light uncon densed portion of the vapors from the secondary fractionating column to condensation, cooling and collection, returning the heavier condensed portion of the vapors from the secondary frac tlonating column to retreatment under vapor phase or relatively high temperature cracking “ conditions in a secondary or vapor phase heat ing element, introducing heated products from tion will assume. Other features of the inven tion will be apparent with reference to this draw ing. Raw oil charging stock supplied through line l and Valve 2 to pump 3 may be fed through lines 4 and 5 and through valve 6 into dephleg mator ‘l where it assists fractionation and cool ing of the vapors in this zone by direct con tact therewith, and may pass together with the insuf?ciently converted portion of the vapors which are condensed in dephlegmator 1, through line 8 and valve 9, back into line It and thence to pump 1. A portion or all of the raw oil charg ing stock, instead of passing overhead to dephlegmator ‘I, may pass directly through valve H in line 4 to pump 16. Pump l0 supplies the charg ing stock and reflux condensate from dephleg mator '1 through line I2 and valve 13 to heat ing element 14. Heating element It is located in a suitable form of furnace i5 and the oil passing therethrough is brought to the desired said secondary heating element into a separate, enlarged reaction zone, vapors from which are conversion temperature, and passes through line 16, and valve ll into reaction chamber l8. subjected to fractionation in a vapor phase de Separation of vapors and liquid is permitted phlegmator and their lighter constituents sepa rately condensed and collected and returning the in chamber 18, the latter being withdrawn from heavier condensed portion of the vapors from the the system or to further treatment through line vapor phase dephlegmator to the primary or liq ' i9, controlled by valve 20, or, ‘if desired, condi uid vapor phase heating element for reconversion. tions may be so maintained in chamber l8 such that the residual product remaining therein is As a feature of the present invention, I pro vide for the introduction of an extraneous oil reduced to substantially dry coke, in which case into the stream of reconverted oil discharging no liquid residue is withdrawn during the opera tion, and the coke produced may be removed at from the secondary or vapor phase heating ele ment to partially cool the stream of heated oil the end of the run. Vapors from reaction cham and prevent excessive formation of coke and ber l8 pass through line 2i and valve 22 into dephlegmator l, where they are subjected to frac gas. Extraneous oil of any desirable charac teristics from any source may be employed for tionation, their heavier, condensed portion re turning, as already described, to heating element this purpose, but preferably I utilize an oil simi 14 for reconversion, and their lighter, uncon lar in characteristics to the re?ux condensate, densed portion passing through line 23 and valve 55 commonly termed “pressure distillate bottoms”, 20 25 30 35 40 45 50 55 2 2,118,605 24 to fractionating column 25. The vapors are subjected to further fractionation in column 25, their lighter, uncondensed portion comprising preferably material boiling within the range of motor fuel withdrawn through line 26 and valve 21, is subjected to condensation and cooling in condenser 28, thereafter passing through line 29 and valve 30 into receiver 3|, where it is col lected as distillate and uncondensable gas. Dis 10 tillate may be withdrawn from receiver 3| through line 32 and valve 33. Gas is released from the receiver through line 34, controlled by valve 35. Re?ux condensate formed in fractionating col umn 25, which in most cases will correspond in 15 characteristics to what is commonly termed “pressure distillate bottoms”, is withdrawn from this zone through line 36 and valve 3'! and fed by means of pump 38 through line 39, valve 40 and line 4| into heating element 42. An ex 20 traneous oil or secondary charging stock, pref erably similar in characteristics to the re?ux condensate from fractionating column 25, and supplied from any desirable source, for example, another cracking system, through line 43 and 25 valve 44, may be fed by means of pump 45, through valve 46 in line 4| into heating element 42. Heating element 42 is located in a suitable furnace setting 41 and the oils passing through from through line 19 and valve 80 into line l2, and thence to heating element M for reconver sion. It will be understood that if extraneous oil or secondary charging stock is fed through line 64 to dephlegmator 63, as described, the ma jor portion of this material thus fed will also be supplied, together with a re?ux condensate from dephlegmator 63, to heating element 54. It will also be understood that the usual ex pedients such as returning a portion of the ?nal 10 distillate from the system to the zone in which it is produced may be employed to assist fraction ation and to maintain the desired outlet tem peratures from the various fractionating zones, thus assisting in controlling the quality of the 15 ?nished product. In this particular case, dis tillate from receivers 3| and/or 1| may be re turned to any or all of the dephlegmators l, 25, and 63 by well-known means, not shown. Pressures employed within the system may 20 range for subatmospheric to high superatmos pheric pressures of 1500 pounds or more per square inch. The primary and secondary crack ing system may be operated under substantially the same or under different pressures, and equal 25 ized or differential pressures may be maintained between the various elements of each system. Cracking temperatures employed may range this heating element are raised to a conversion 30 temperature, preferably higher than that em from about 750 to some 1200" F. more or less. Preferably, milder cracking conditions are em 30 ployed in heating element l4, and are discharged through line 48 and valves 49 and 50 into reaction chamber 5|. Provision is made for the intro duction of a portion or all of the extraneous oil 35 or secondary charging stock from pump 45 into the stream of heated and. reconverted material element 42. As a speci?c example of the operation of the process, such as above described, two charging stocks are supplied to the system, one, a fuel oil 35 from heating element 42. This is accomplished by diverting the oil from line 4|, through line 52 and valve 53 into line 48. This feature is pro vided for the purpose of cooling the stream of heated ?uid from heating element 42 to a point where undesirable secondary cracking reactions will not occur, thus eliminating or materially re ducing the excessive coke and gas losses char 45 acteristic to vapor phase cracking reactions. Separation of the liquid and vapor is permitted in reaction chamber 5|. The liquid withdrawn through line 54 and valve 55 to pump 56 may, all or in part, be discharged from the system through line 51 and valve 58, or may be fed through line 59 and valve 60 into line |2 and thence to heating element l4 for reconversion. Vapors from re“ action chamber 5| pass through line 6| and valve 62 into dephlegmator 63, where they are subjected to fractionation, assisted, if desired, by a portion of the extraneous oil or secondary charging stock from line 43, supplied through pump 45, line 64 and valve 65 to dephlegmator 63 into direct contact with the vapors in this The lighter portions of the vapors from 60 zone. dephlegmator 63, preferably comprising mate rial boiling Within the range of motor fuel, are withdrawn through line 66 and valve 61, sub jected to condensation and cooling in condenser 65 68 and thence passed through line 69 and valve 10 to be collected in receiver 1|, distillate from which is withdrawn through line 12 and valve 13, and uncondensable gas from which may be released through line 14, controlled by valve 15. Re?ux condensate from dephlegmator 63, com prising the heavier or insu?iciently converted portion of the vapors from the vapor phase or relatively high temperature cracking reaction, are withdrawn from dephlegmator 63 through line 16 and valve 11 to pump 18 ‘and fed there ployed in heating element l4 than in heating of about 26° A. P. I. gravity, being the charging stock to the primary or relatively low tempera ture system, represents about 70% of the total charge, while the secondary charging stock, fed in part direct to the secondary or relatively high 40 temperature heating element and in part into the stream of heated products discharging from this same heating element, represents about 30% of the total charge and corresponds in charac teristics to the additional material supplied to 45 this heating element from the secondary frac tionating column of the primary system. Re?ux condensate from the dephlegmator of the pri mary system is returned to the heating element of the same system for reconversion, and re?ux 50 condensate from the dephlegmator of the sec ondary system is also returned to the primary heating element. A temperature of approxi mately 925° F., and a pressure of about 230 pounds per square inch is maintained in the heating element of the primary system. This pressure is substantially equalized throughout the reaction chamber and primary dephlegmator. It is reduced to about 60 pounds per square inch in the secondary fractionating column and in 60 succeeding parts of the primary system. A tem perature of approximately 1100° F. is main tained at the outlet from the secondary heating element, but this temperature is reduced to ap proximately 875" F. in the reaction chamber of the secondary system by the introduction of sec ondary charging stock into the stream of heated material entering this chamber from the heat ing element. A pressure of about 150 pounds per square inch is maintained throughout the sec 70 ondary cracking system. In an operation such as above outlined, a yield of approximately 65% of ?nished motor fuel having anti-knock value equivalent to a blend of 50% benzol with 50% straight run Pennsylvania gasoline may be pro 75 3 2,118,606 duced. Based on the total charging stock, about 17% of substantially dry coke is produced in the primary reaction chamber and about 6% of re sidual oil is recovered from the reaction cham ber of the secondary system. This latter may, if desired, be returned to the primary heating element, and when the process is so operated the gasoline yield may be increased by a little less than 4%, with a slight increase in coke and gas 10 formation. 7 Having thus described my invention, what I claim is: The process of treating hydrocarbon oils that comprises subjecting hydrocarbon oil in a ?rst cracking zone to a substantially liquid phase cracking temperature’ to e?ect conversion of the high boiling hydrocarbon oils into lower boiling hydrocarbon oils, vaporizing the lower boiling hydrocarbons of the cracked products, withdraw 20 ing the unvaporized oil from the system, frac tionating the evolved vapors in a ?rst fraction ating zone to form a gasoline-like vapor fraction, a lighter reflux condensate and a heavier re?ux condensate, returning the heavier condensate to said liquid phase cracking operation, subjecting said lighter condensate to a vapor phase cracking temperature in a second cracking zone, contact ing relatively heavy fresh charging stock with the resulting vapors from the vapor phase crack ing operation to thereby vaporize a portion of the fresh charging stock, withdrawing the unvapor~ 1O ized portion of the charging stock from the sys tem, dephlegmating the combined vapors from the vapor phase cracking operation and the va— pors from the fresh charging stock in a second fractionating zone to produce a vapor fraction 15 suitable for the production of gasoline and a re flux condensate suitable as a clean cracking stock and charging said clean cracking stock to the liquid phase cracking operation. 20 LYMAN C. HUF'F.