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Junè 14, 1938. LE ROY G. STORY 2,120,655 , CONVERSION OF HYDROCARBON OILS Filed April 21, 1951 l è,»nä,É- . MANGMWhI. Y .5% ¿mig l BY @545W .Patented June 14, l‘i938 2,120,t55 UNITED STATES PATENT OFFHCE 2,12 0,655 CONVERSION 0F HYDROCARBON OILS Le Roy G. Story, Mount Vernon, N. Y., assigner to The Texas Company, New York, N. Y., a cor poration of Delaware Application April 21, 1931, Serial No. 531,693 7 Claims. -This invention relates to the conversion of hydrocarbon oils and has to do particularly with la combination of liquid phase and vapor phase cracking which provides certain advantages and presents features of novelty that will be more fully described and claimed hereinafter. An important object of the present-invention is to produce from a fresh charging stock, es sentially, a residue of coke, a distillate of gaso 10 line having a high antiknock value and fixed gases which may be used as fuel or for other purposes as desired. The invention contemplates the stripping of fresh charging stock by contact with the vapors 155 from a coking operation, the separation of a clean cracking stock for a pressure cracking system, the separation of selected cuts for vapor phase cracking and the coking of the residue liquids from the stripping and pressure cracking opera 20 tion by the sensible heat of the vapor phase cracked products. With suitable type of appara tus and novel methods of operation the volatile products may be concentrated at one zone in the system whereby a gasoline of high anti 25 knock value, consisting of both liquid phase and vapor phase cracked products, may be separated, the heavier components fractionated to produce selected cuts which may be subjected separately to a pressure cracking system and a vapor phase 30 cracking system, while the unvaporized residual oil from the system may be reduced to coke in coking stills. The process of the invention is flexible so that` a wide selection of cutsv for cracking may be made by segregating various fractions accord ing to the desired volatility or refractorinessand each fraction subjected to the most suitable type of conversion operation. .Accordingly, the low boiling products vaporized in the pressure crack ,10 ing operation may be separately dephlegmated to produce selected cuts for vapor phase and liquid phase cracking; the residual liquid or pres sure tar may be flash distilled under reduced pressure to likewise produce selected cuts for the 45 same purpose, if desired; or, the entire vapor fraction from both the pressure stills and the flash still may be concentrated in one large tower, which also receives vapors from the crude strip per, and the resulting mixture of vapors frac tionated to separate the desired gasoline, and to produce at the same time a fraction suitable for vapor phase «cracking stock and a clean con densate adapted for pressure still cracking. The invention may be more clearly understood 55 by referring to the accompanying drawing where '(Cl. IBG-Jill) in an apparatus is shown for conveniently carry ing out the invention and forming one embodi ment thereof. f’ . In the drawing the reference character l rep resents a heater for heating oil under pressure; 5 2 and 3 a pair of stills for separating vapors from residual oil; ¿l a dephlegmator for dephleg mating or'fractionating vapors from the stills 2, 3; 5 a vapor phase cracker for cracking oil in the Vapor phase; ß and 'i a flash still and dephleg mator for vaporizing residue and fractlonating the vapors from the stills, 2, 3; 8 and 8a, coke stills for reducing residual oil to coke by the heat of the cracked products from the Vapor phase cracker 5; and 9 a combined stripper and fractionating tower for stripping crude- and for fractionating any> or all the vapors from thestills 2, 3, flash still 6, vapor phase cracker 5, and coke stills 8 and 8a. The heater I comprises any well known type oi furnace having a coil or tubular heater l0, located therein, and connected to an extraneous supply line ll and a clean distillate charge line l2. A burner i3 supplies heat to raise the oil passing through the coil Il) to conversion tem- _,_ peratures. A transfer line Hl, conducts oil from the heater to either or both of the stills 2 and_3 by means of the branches l5 and I6 respectively. The stills 2 and 3 are shown as vertical cham bers having a vapor connecting line 2l] and a liquid overñow pipe 2l. The vertical type of still is shown for illustrative purposes only and other shape and designs of stills may be employed, if desired, with equal success. The stills are pref erably insulated to retain the heat content of the oil and provide reaction time at conversion tem peratures. Each still is provided with residue draw-off lines 2,3 and 24 for withdrawing residual liquid continuously or intermittently. A vapor pipe.25, regulated by a valve 26, conducts Vvapors from the stills 2 and l3 to a line 2l, referred to hereinafter. A branch line 28, in which is inter posed a valve 29, serves to conduct the vapors, if desired, to the dephlegmator 4. 'I‘he dephlegmator 4 may conveniently take the form of a bubble tower equipped with trays to contact the vapors and reflux condensate. A. cooling coil 30 is provided in the top of the de phlegmator to supply cooling thereto by an eX traneous cooling medium. A vapor pipe 3l con ducts vapors from the dephlegmator to a con denser coil 32. A condensate line 33 serves to convey the condensate from the condenser to a receiver 34 which is equipped with the usual gas _release line 35 and liquid draw-off pipe 36. 2 2,120,655 The dephlegmator is further provided with lines 36’ and 31, regulated by valves 33 and 39 respectively, communicating with the bottom thereof to withdraw reiiux condensate from the bottom of the tower. A line 40, in which is 6I and 84 whereby the residuum from the flash still 6 may be contacted with the products from the vapor phase cracker. A clean distillate or reflux condensate line 85, connected to line 43, serves to withdraw conden~ interposed a valve 4l, connected to the side of the dephlegmator, serves to withdraw a side cut sate collecting in the bottom of the fractionator E3 or condensate in line 21 to storage or to conduct therefrom, if desired. the lcondensates to the charge line 84 whence they The reflux condensate pipes 36 and 81, as well as the side pipe 4D, sepa rately connect to a line 21, referred to hereto fore, which communicates at diiferent elevations with the upper fractionating section of the tower 9 by means of branch lines ï42 and ‘43. A line 45, regulated by valve 45, communicating with 15 the line 21, leads to the tubes or‘coil 41 located in the vapor phase cracking furnace 5. The vapor phase cracker 5, shown for purposes of illustration as a diagrammatical section, may be any well known or preferred type of Ivapor are forced by pump 9| to the coil i8. A conden sate line 93, connected to the side of the fraction li) ator and having a pump 93', serves to conduct, if desired, a side cut from the fractionator to the line 45Íleading to the vapor phase cracker 5. A vapor line .95 conducts vapors from the top of the frac tionator .to the condenser coil 96. A condensate ïline TS1-connects the condenser coil 98 to a re ceiver 95 which is equipped with the usual gas releaseline 99 and liquid draw-oli? line |88. In -practicing the invention with an apparatus phase cracking apparatus. A convenient type of such as that shown lin the drawings, charging 20 stock, such as crude oil,~is-charged tothe stripper furnace for such use maybe similar to that dis closed in U. S. Patent No. 1,717,334, June 11, through line 62 wherein the fresh charge comes 1929, to Luiz de Florez. A pipe 48, controlled by in Contact with the hot vapors therein and the valves 49 and >5t, connects the cracking vcoil 41 charge may be partially cracked and the lighter tothe stripper section of `the tower 8. Branch constituents vaporized. The vapors, including lines 5| and 52 connect .the line 48 to the coke the volatilized constituents of the fresh charge, stills '8 and 8a.. A vapor line 53 serves to conduct pass throughV the riser 8l to the fractionator. A clean distillate collects above the partition 8D vapors from the coking stills 8 and 8a to the bot and is conducted vby the lines 88 and 54 to the tom of the stripper section of tower 9. ` -Referring now Vto the flash still 6, a »residue pressure crackingv coil 10. The clean distillate 30 30 line `55 serves to `conduct residuum thereto from passing to the coil I0 is preferably >a cracking stock of the nature of gas oil. If desired, an ex the stills 2 and 3. A vapor ‘line 55 conducts va pors from the iiash drumïö to the dephlegmator 1. traneous >charge of o'il may be introduced through A vapor line 58 connects "the dephlegmator 1 toV the'line ~Il. The addition of extraneous oil is sometimes desirable in order to provide a uniform to Ul the line 21 referred to heretofore. A residue draw-off line 68 serves to'wìthdraw residue from charging rate in case the supply from the frac tionator runs low and more particularly is such the flash still 6. A-branch line 8l serves to con duct the residue, if desired, to a charge line 62 a supply of charge from ïline H convenient in starting up operations. A , leading to the stripper section of tower 9. A re The oil in the heating coil i8 is raised to con 40 iiux condensate line ‘63 conducts reflux conden sate from the bottom of dephlegmator 1 >to the version temperatures of the order of '150° F. clean distillate charge line 84. A branch line 65, 950" 'FL and a pressure of 200-600 pounds per controlled by valves 66 and 61, connects the re~ square inch may be carried on the coil and stills 2 and -'3. Two stills are shown in the drawings flux line V153 with the line "21, wherebyv the con densate may be transferred to the fractionator but any number may be used. Likewise, the stills 215 are' shown connected with vapor lines and liquid 9. A branch line 68, controlled by valve 159, con nects the line 55 to the line-21 ahead of valves overflow lines, but it is contemplated that a low 18 and 1| in line 21 so that the condensate,` if liquid level may be maintained in the stills in desired, may be sent to the vapor phase cracker which case there would be no overflow but instead via lines 21 and 45. A condensate line 15 serves the >hot oillmay be charged to one or both stills 50 andthe entire contents of the stills maintained to withdraw condensate from the middle of de phlegmator 1 to the line v65. substantially Vas vapors. The vapors from the Referring to the stripper and >fractionator 9, it stills Zand 3 pass through-the line 25 and may will be noted that vthe upper section of the `tower be passed directly to the fractionator 9 through ' constitutes a fractionating »tower while the lower section constitutes the stripper. The sections are separated by a partition 88 having a Vapor riser 8i therein so that vapors from the stripper may pass to the fractionator. While the stripper and 60 fractionator are shown as a single tower with the fractionator superimposed on the stripper, never-> theless the two sections may be made as separate units and the invention contemplates such an arrangement. Y v A charge line 62 leads to the top of `the stripper to conduct fresh charge thereto aswell as re siduum from the line 6I, if desired. A residue draw-,olf line 83 serves to withdraw unvaporized oil from the bottom of the stripper. A branch line 70 B4, having a pump 84'` serves to transfer the re siduum from line 83,7if desired, to the line 48 `to be mixed with the cracked products from the va por phase cracker 5 and thence to be conducted to the coke stills or to _the stripper. A branch line 85, controlled by valve 86, connects the lines line 21. " .. In one method of operation'the vapors from stills 2 and 3 may be passedthrough rline v28 to the dephlegmator 4. In the dephlegmator the vapors are fractionated to separate a gasoline fraction which Yiscondensed in condenser 32 while the heavier constituents are collected as reflux con dens'ate. The reiiux condensate may be collected entirely in the bottom of the tower .4 or separated into selected cuts and o_ne Ycut taken off as a side stream throughV line 4'0. In case a side stream is taken off it is preferable to charge this cut to the vapor phase cracker through line 45 while the heavier cut in the bottom of the tower 4 is passed through line 36 and line 21 to the frac tionatorrg or directly to line 80 to be backtrapped to the heater coil I8. When no side cut is taken from the tower >4 then the reflux may be passed entirely, or in part through lines 31 and 45 to either the vapor phase cracker 5 or the tower 9. The residue from stills 2 and 3 may be con- u 2,120,655 ducted continuously or intermittently to the flash still 6. A reduced superatmospheric pressure is maintained in the still 6 so that the lighter frac tions of the residual oil are immediately flashed by their sensible heat into vapors. The vapors pass to dephlegmator 1 while residue is with drawn through line 60 to be disposed of as de scribed hereinafter. The vapors in dephlegmator 1 may be separated into one or more cuts, asV de sired. In some cases it may be desirable to pass a substantial amount of the vapors to vapor phase cracker 5 and this may be done by suitable regu lation of valves 10 and 1I in line 21, or the vapors by other regulation of the same valves may be sent directly to the fractionator 9. Likewise, one or two cuts of condensate may be made in theV tower 1, these cuts being drawn off through lines 63 and 15. In this way a side cut may be taken off through line 15 and sent to the vapor phase cracker by suitable regulation of valve 69 in branch line 68 and valve 61 in line 66, while a heavier condensate from the bottom of tower 'I may be returned to coil I0 through line 94. In some cases it may be desirable to make a single cut of condensate in tower 1 and this cut may be withdrawn through line 63 and passed to the coil I0 or conducted through line 65 to either the vapor phase cracking coil or to the fractionator 9 by suitable regulation of valves 69 and 61 in 30 lines 68 and E6 respectively. Y While I have described the manner in which particular fractions from either the dephlegma tor 4 or dephlegmator 1 may be passed to the vapor phase cracker 5 or the fractionator 9, it is to be understood that selected fractions of liquids and/or vapors from both dephlegmators may be passed simultaneously to the Vapor cracker 5 or fractionator 9. It will be observed therefore that ñexibility of operation isV an essential feature of ‘my invention whereby selected outs may be 3 -entirely or in part, alone or in mixture with the residuum from flash still 6, into the line 48 to be treated as just described. The vapors collecting in the .fractionator sec tion of tower 9, which may comprise all or a` part of the vapors from the entire system, depending on whether the dephlegmator Il is by-passed, are fractionated and the reflux condensate or clean distillate, entirely or in part, passed to the heat er coil I9. Sometimes it is desirable to separate the reñux condensate into selected cuts, and therefore, I have shown a line 93 for making a side cut to be returned to the vapor phase cracker 5. The latter is particularly advantageous in case the dephlegmator 4 is by-passed and all the va pors concentrated in the fractionator section of tower 9. Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and 20 scope thereof, and therefore only such limitations should be imposed as are indicated in the ap pended claims. I claim: l. The method for conversion of hydrocarbon oils which comprises passing fresh charging stock into contact with vapors from a coking Zone to form unvaporized liquid and vapors, fractionat ing said vapors to form a vapor fraction and a re flux condensate, subjecting said condensate to conversion conditions of temperature and super atmospheric pressure to separate low boiling products as vapors from residual oil, flash distill ing said residual oil to produce an unvaporiz/ed residual liquid and a selected distillate for vapor I: phase cracking, subjecting only said selected dis tillate toa vapor phase cracking operation, mix ing the unvaporized residual oil from the system with the products from the vapor phase cracking operation and passing the resulting mixture to 40 treated in a manner to provide optimum con said coking zone. ditions for both yield and quality of the desired 2. The method for the conversion of hydrocar bon oils by a series of continuous steps which comprises subjecting a hydrocarbon oil to con version conditions of temperature and superat mospheric pressure to produce a vapor fraction and an unvaporized residue, fractionating said ñnished products. The oil in passing through vapor phase cracker` 5 is raised to a temperature suitable for conver sion in the vapor phase, say between 950° F. and 1150° F. The hot products of conversion may be transferred through line 48 directly to the strip per section of the tower 9. It is preferable, how . vapor fraction in a first fractionating zone to form a desired product, subjecting the unvapor ized residue to flash distillation in a flashing Zone 50 under a reduced superatmospheric pressure, fractionating the vapors evolved during ñash dis ever, that these products go to the coke stills 8 and 8a by means of lines 5l and 52, in order that the heat thereof may be used for coking the re sidual oils from the system. Two coke stills are tillation in a second fractionating Zone to sepa shown, for purposes of illustration, but only one ' rate a selected fraction suitable for vapor phase is ordinarily used at a time while the other is cracking, subjecting said fraction, while still re cleaned of the coke deposition therein. The va taining heat from its previous treatment, to a pors from the cokegstills pass through lines 53 to vapor phase cracking operation, conducting the the stripper section Where they contact the heavy vapor phase cracked products to a coking Zone, oil charged thereto through line 62. separate fromA said flashing zone, passing the va The residual oil from the system -is preferably pors from the coking Zone to a stripping zone, in Gr) commingled with the hot vapors from the vapor troducing fresh charging stock into said stripping phase cracking operation. Referring first to the zone, separate from said flashing Zone, separating a clean condensate from the resulting vapors, residuurn from the flash still, this oil may be passed through lines 6l and 62 to the stripper. utilizing clean condensate so obtained, as said hy „ It is preferable, however, to by-pass it through drocarbon oil undergoing conversion, and pass lines 85 and 84 to be commingled with the vapor ing residual oil from the stripping Zone to said phase cracked products. Therefore, this residue coking Zone. 3. The process of treating hydrocarbon oil may be used to cool the cracked products in case they are passed directly to the stripper through which comprises introducing crude oil into a line 48 or the mixture of residuum and vapors stripping zone, wherein heat is supplied by hot may be passed through lines 5| and 52 to the vapors and the crude is partially vaporized, col coke stills where the residue is reduced to coke lecting a clean, relatively heavy condensate, and by the sensible heat- of the vapors. Likewise, the an intermediate condensate, and condensing the unvaporized oil collecting in the bottom of the lightest of the crude vapors as a desired product, stripper is withdrawn through line 83 and passed introducing said relatively heavy condensate into 55 60 65 70 4 2,120,655 a cracking Zone wherein cracking conditions of ' temperature and pressure are maintained and said condensate is subjected to conversion, separating the products of conversion into vapors and a liquid residue, extracting gasoline from said vapors, in heated cracked vapors into said coking zone to maintain the temperature thereof, and intro ducing hot vapors from saidrcoking Zone into said stripping Zone to aid in the stripping thereof. Y reduced pressure wherein partial vaporization 5. A process in accordance with claim 3 where in said relatively heavy condensate second men thereof takes place, subjecting resulting vapors to partial condensation to form a relatively heavy tioned is recycled to said cracking Zone first mentioned. condensate and an intermediate condensate, leav 6. A process in accordance with claim 3 where in unvaporized portions of said crude charging troducing said residue into a iiashing zone of ing relatively light vapors uncondensed, introduc ing the residue from said ilash Zone into a coking zone, cracking in the vapor phase the intermedi oil are introduced into said coking zone. ' highly heated cracked vapors into said coking Zone '7. The method for the conversion of hydro carbon oils by a series of continuous steps, which comprises subjectingY a hydrocarbon oil to con to maintain the temperature thereof, and intro version conditions of temperature and superat ducing vapors from said coking Zone into said mospheric pressure to produce a vapor fraction and an unvaporized residue, fractionating said vapor fraction, in a iirst fractionating Zone, sub ate condensate last mentioned, introducing the crude stripping Zone to aid in the stripping of said crude oil. 4. The process of treating 'hydrocarbon oil which comprises introducing crude oil into a stripping zone wherein heat is supplied by hot vapors, and the crude is partially vaporiz'ed, col lecting a clean relatively heavy condensate and condensingA the lightest of the crude vapors as a desired product, introducing said condensate into a cracking zone wherein cracking conditions of temperature and pressure eXistand said con densate is subject to conversion, separating the products of conversion into vapors and a liquid residue, extracting gasoline from said vapors, in troducing said residue into a iiashing Zone of reduced pressure wherein partial vaporization thereof takes place, subjecting resulting vapors to partial condensation to form a condensate, leaving relatively light vapors uncondensed, in roducing the residue from said iiashing zone into a coking zone, cracking in the vapor phase the condensate last mentioned, introducing the highly jecting the unvaporized residue to flash distilla tion in a Íiashing Zone under a reduced superat mospheric pressure in a flashing Zone, separate and apart fromthe coking zone hereinafter speci ñed and from the resultant vapors produced in the coking operation, fractionating the vapors evolved during iiash distillation, in a second frac tionating zone, to separate a selected fraction suitable for vapor phase cracking, subjecting said fraction, while still retaining heat from its previous treatment, to a vapor phase cracking 30 operation, conducting the vapor phase cracked products to a coking zone separate from said iiashing zone, passing the vapors from the coking zone to a stripping zone, introducing fresh charg ing'stock into said stripping zone and passing 35 residual oil from the stripping zone to said coking zone. LE ROY G. STORY.