Патент USA US2118288код для вставки
May 24, 1938- - H. v. ATWELL . _ 2,118,288 TREATMENT OF HYDROCARB‘ONS Filed July 25, 1935 2 Sheefs-Shéet 2 157“ INVENTOR HAROLD l’. ATWELL ATTORNEY Patented May 24, 1938 ‘ 2,118,288 “UNITED STATES PATENT OFFICE 2,118,288 . '- TREATMENT OF HYDROCARBONS Harold v. Atwell, White Plains, N. Y., assignor to Gasoline Products Company, Inc., Newark, N. J., a corporation oi’- Delaware ' Application July 25, 1933, Serial No. 682,059 , 5 Claims. (Cl. 196-9) My invention relates to the treatment of hydro- ‘ carbons containing crackedv constituents includ carbons, more particularly hydrocarbon oils and ing unsaturated hydrocarbons, together with hydrocarbon gases containing unsaturated con small quantities of oxygen, the mixtureof gases stituents such as ole?ns, and my inventionhas for or vapors thus obtainedbeing brought into con objects the provision of a process of effecting . tact with hydrocarbon liquid containing reactive 5 inter-reaction between such hydrocarbon oils and hydrocarbon constituents at elevated pressure gases and the recovery of valuablev products there and temperature, and the products being'frac from, as well as such further improvements in operative advantages and results as may herein tionated as desired. In one aspect, my invention contemplates a process‘ in which gases resulting from the com bustion of a suitable fuel are reduced in tem after be found to obtain. With these objects in view, my invention con templates contacting gaseous ole?ns or the like with normally liquid hydrocarbons containing une saturated, aromatic or naphthenic hydrocarbon constituents, such, for example, as so-called “pressure tars” and other residual oils produced in the pyrolytic decomposition of petroleum, pe troleum oils or the like, the contact taking place. at elevated temperatures in the presence of limit ed quantities of oxygen or gases containing-same, withthe result that inter-reaction between the various hydrocarbons takes place resulting in the ‘formation of valuable oils of intermediate boiling points compared to the hydrocarbons initially ' employed. - While the nature of the reaction or reactions taking place, due input to the complex nature perature to a suitable point and brought into contact with hydrocarbon gas or oil to crack the same, the resultant mixture of gases or vapors, products of combustion and, it-may be, oxygen, being further reduced to a temperature of for ex ample 1750" to 1000° F. and contacted at that tem-, perature with residual-oil or tar, with or without the introduction of additional quantities of oxy gen or oxygen-containing gases as desired, the products of reaction being fractionated as indi cated hereinabove. ' , In order-that my invention may be clearly set forth and understood, I now describe, with‘ re? erence to the drawings accompanying and form ing a part of this specification, a preferred man ner in which my invention may be practiced and of the hydrocarbon materials present, is obscure ,and my invention is not to be considered as lim ited in scope by'any particular theory of the. na ture of such reaction, it is believed that certain hydrocarbons which are present in tars and other residual oils of the character set forth arep'ar partly in elevation and partly in verticalsection, of apparatus for treating hydrocarbons in ac tially dehydrogenated by the oxygen, forming of apparatus for carrying out my process. ~ compounds which are highly reactive and com embodied. In these drawings,‘ ' ‘ vFigure 1 is amore or less diagrammatic view, , cordance with my present invention; and Figure 2 is a similar view of an alternative form ' Similar reference numerals designate similar bine readily with other unsaturated hydrocarbons parts in bothv views of the drawings. such as gaseous ole?ns, to form hydrocarbon oils of intermediate boiling points suitable for use Referring now to the drawings, there is shown an apparatus comprising in part a refractory either as such or after suitable pyrolysis ‘in the lined furnace or combustion chamber l , a refrac preparation of motor fuel or gasoline. Thus I may subject gaseous ole?ns or gases containing the same to contact at elevated tem perature, preferably at a temperature within what ‘ber 3, a dephlegmator 4, a fractionating tower 5, ‘and a gas separator 6. The reaction chamber 3 may be designated‘ as a range vsuitable ‘for the cracking of hydrocarbon oil,'for example, from _ tory-lined cracking chamber 2, a reaction cham may be empty or provided with gas-and-liquid contact devices commonly used in the oil-crack 45 ing art. 750° to 1000° F., and under elevated pressure, with residual or other hydrocarbon oils f the character set forth, in the presence of /imited quantities of oxygen or gases containing .the same, the resultant products of reaction being A suitable fuel such as oil or gas is introduced .to a‘burner ‘I located in the combustion chamber . removed and fractionated. as desired to recover The proportions of fuel and air may be- adjusted ' normally liquid hydrocarbon products therefrom, My invention further contemplates a method wherein ‘hydrocarbon gases or oil may be cracked in such manner as to produce a mixture of hydro I through an inlet 8 having a pump 8a and valve 9; while air for combustion of the fuel is intro duced to the burner 1 through a valved inlet Hi. to’v to give substantially complete combustion or to provide an excess of air over that required for the combustion of the fuel. The products of _ combustion leave the combustion chamber l and 65 2,118,288 . are passed through a refractory-lined duct 12 to in part by reaction with the hydrocarbon gases or oil introduced into the latter, thus'requiring' the cracking chamber 2. _ the addition of further quantities of oxygen at 22. It is sometimes desirable to reduce the temper By means of a pipe 24, I introduce into the ature of the products of combustion to about 1500° F. before entering the cracking chamber 2 mixture of gases entering the upper portion of the reaction chamber 3 a suitable hydrocarbon and for this purpose I provide a valved inlet pipe liquid, preferably one containing a considerable l3 for steam or other diluent gas, and a valved in let pipe, I4 for air or oxygen, both of which pipes amount of unsaturated, aromatic or naphthenic conveniently communicate with the duct l2, as hydrocarbon constituents. Various heavy oils 10 shown. Any of these gases, or a mixture thereof, may be admitted to the products of combustion in such amount as to reduce. the temperature there of to about 1500° F. Where air or oxygenis ad mitted‘at this point, the amount of the same ad 15 mitted is such as to e?ect combustion of any combustible constituents such as carbon monox ide, which may remain in the gases of combustion leaving the combustion chamber, and preferably also to provide a small amount of free oxygen 20 in thegases entering the cracking chamber 2. In the instance illustrated in Figure l, the gases entering the reaction chamber 2 through the duct l2 pass upward through an interiorly disposed duct I5 to the top of the reaction chamber 2 and 25 then downward through a chamber I6, within “ obtained in the pyrolytic decomposition of hydro 10 carbon oils, and preferably residual oils or tars high in reactive constituents, may be employed. Through contact with the hot gases entering the reaction chamber 3, which gases contain such unsaturated hydrocarbons as gaseous ole?ns or 15 the like together with. small quantities of free oxygen, constituents of the liquid introduced through the conduit 24 are caused to react with hydrocarbon gases within the reaction chamber 3 resulting in the formation of hydrocarbons of 20 intermediate boiling points. Preferably, thetemperature within the reaction chamber 3 is maintained within a range of from about 750° to about 1100“ F. Where ,the tem perature of the gases leaving the cracking cham 25 which I may provide bodies I‘! of checkerbrick ' ber I6 is considerably above this range, cooling or other refractory and heat-accumulative mate may be e?ected by means of gas or liquid intro rial. duced ‘through the inlets 22, 23 and 24, respec tively, as will be readily understood by those , Hydrocarbon gas or oil of suitable character 30 30 is introduced into the cranking chamber I6, to - skilled in the art. While, as indicated hereinabove, I do not rely be cracked by direct contact with the hot gases passing through the latter. In the instance upon any particular theory as to the nature of shown in Figure 1, I provide valved gas inlets I8 and I9 communicating with the interior of the 35 chamber I6. , - The mixture of hydrocarbons, gases of com bustion, and it may be excess oxygen and steam or other diluent gas, transverse the cracking chamber ~l6 at a temperature of from 750° to 2500“ 40 F., the time of contact being so controlled as to effect material cracking of the hydrocarbon gas, resulting in the formation of unsaturated hydro carbons, such as gaseous ole?ns or other reactive compounds. The products then pass through a conduit 2| into the reaction chamber 3. At this point, additional quantities of air or other oxygen-containing gas or diluent gas may be introduced through a valved inlet 22 communi eating with the conduit 2 I, while additional quan 50 tities of gaseous ole?ns or gases containing the same, such for example as gases produced in the cracking of hydrocarbon oils, may be introduced through a valved inlet 23 communicating with the reaction chamber 3. 55 , the reaction taking place in the chamber 3, nevertheless it is probable that the oxygen present c-?ects a limited dehydrogenation of the hydro 35 carbon liquid or unsaturated constituents thereof, the resultant highly active products of reaction combining with gaseousole?ns or otherwise poly merizing or reacting in the presence of the cracked hydrocarbons entering the reaction chamber 3 through the conduit 2! to form prod ucts of intermediate boiling points. The reacting materials in the chamber 3 may be maintained under a substantially atmospheric pressure. Preferably‘, however, they are main 45 tained under an elevated pressure, for example, from 50 to 200 pounds per square inch, or even higher if desired, and the same or higher pres sures may be maintained in the chambers l and 2. The gases and vapors reaching the bottom of 50 the reaction vessel 3 are withdrawn therefrom through a conduit 30 having a valve 3|, and may pass to the dephlegmator 4, or through a branch line 32 having a valve 33 directly to the frac tionating tower 5. Ordinarily, however, I prefer 55 to pass the gases and.vapors through the dephleg mator' 4 before admitting them to the-fractionat or at .22, the process is preferably so conducted ' ing tower 5. The dephlegmator 4 is preferably Irrespective of whether excess oxygen beyond that required for combustion'of the fuel intro duced at the burner ‘l is introduced at In, at M, that the mixture of gases entering the reaction 60 chamber. 3 contains free oxygen. ‘The introduc tion of air or oxygen-containing gas is so regu lated as to provide a volume of oxygen less than that of the hydrocarbon gases or vapors present, and preferably equal to from 20 to 50 percent of 65 ‘the volume of the hydrocarbon gases and vapors. It will, of course, be readily understood that the speci?c ratios employed will vary with the nature of the hydrocarbons, the temperature and. the nature of the results desired. It will further be 70 obvious to those skilled in the art that explosive mixtures of oxygen-containing gases and hydro carbons are to be avoided. ' ' Excess oxygen admitted to the system prior to the introduction of ‘the gases of combustion into 75 the cracking vessel 2 may be consumed wholly or provided with a plurality of ba?les 35iand an in let 36 for introducing a suitable re?ux oil. so" The liquid products of'reaction are withdrawn from the reaction vessel 3 through an outlet 31 having a valve 38, while liquid products from the dephlegmator 4 are withdrawn therefrom through 65 an outlet 39 having a valve 40 and leading to a pump 4|. The‘ former may be run to storage through a branch line 42 having a valve 43, or may be delivered to the pump 4|’ through a branch line 44 having a valve 45. ' 70 ‘The heavy liquid products removed from the reaction vessel 3 and/or those removed from the dephlegmator 4, may be delivered in part or in .whole to the reaction vessel 3,,through'a conduit 46, a branch line 41 having a valve 48 and the 75 2,118,998 inlet 24, or to the burner ,1 through a branch line , . ' 3 example, from 400? to 609° _F., or even to a crack ing temperature of, for example, from about 750° 49, having a valve_5_9, andthe conduit 9. The partially dephlegmated vapors from the .to 1000° F. ‘The resultant heated products are dephlegmator 4 and/‘or the vapors from the con‘- . then discharged through conduits 95 and 95 and duit 32 pass through a conduit 52 to the lower the inlet 24 to the reaction chamber 3. _ _ part of the iractionating tower 5, which is pro-‘ , v I The coils 99 and 9| may also be used for a sim vided with a plurality oi, plates or trays 53 of ilar purpose and in the speci?c instance illus-v trated in Figure 1 are employed tor the‘cracking suitable design, as'well as an inlet 54 for admit ting re?ux oil. By means of cooling e?ected by o! a suitable oil such, as, gas oil, for example, gas 0 the ‘addition of re?ux to the tower 5 or otherwise, oil recovered in the fractionating' tower 5., .Such. the vapors passing up through the latter are frac gas oil may be delivered to the‘coils 9| and 99 by means of-the pump 51 and atconduit 99, while tionated, conditions being preferably so regu lated as to recoverla traction of the nature of a‘ ‘ additional gas oil may also be supplied to the gas oilv which collects in the bottom of the tower coils Bi and 99 through a conduit 9|. , In this 15 5,_i'rom which it is withdrawn by means of a‘ instance, I provide a reaction vessel 92, a primary 15 conduit 55 having a valve 56 and leading ‘to a dephlegmator 93 and a ‘fractionation tower 94, pump 51. ‘ _- , Fresh oil, for example, a crude petroleum or a . A portion of this gas-oilfraction may be with drawn through the line 35, wherein is located a 20 valve 53, and delivered to the dephlegmato‘r 4. reduced crude is introduced-to the system by means of a pump 95 through a conduit '95 to pass through a heat-exchange coil 91 located in the upper? portion of the fractionating tower- 94, and after ,leaving the fractionation tower 94 passes through a conduit 99 to lie-discharged This portion of the gas-oil fraction may be cooled. if desired, before introducing it into the dephleg mator 4. ' ' ' _ - The gases and uncondensed vapors withdrawn into the interior of the dephlegmator 93, the in .25 from the top of the tower 5 pass through a vapor terior of which is provided with baihes 99,. line 99 to a condenser 5|, and thence through a , In the dephlegmator 93,‘the heated charge oil line .62 .tothe gas separator 9. Condensate, com- ‘ is subjected. to direct contact with hot vapors _- ‘ prising a low boiling'hydrocarbon liquid of the passing from the ‘reactionyvessel 92 through. a naphtha or gasoline type, is withdrawn from the o separator 9 through a-conduit 53 having a valve 54. A portion of the condensate maybe returned ‘as ,re?ux to the tower 5 through the line 54, . which is provided with a valve 55 and a pump 99 for this purpose. ‘ . vapor line l9l into the bottom 'of the dephleg mator‘ 93, and a combined dephlegmating and distilling action takes‘place. Resvidual portions of the charge oil, together with ‘condensed portions of the vapors entering the dephlegmator, 93,_ are , withdrawn from the bottom of the dephlegmator > Uncondensed gases are removed from the sepa I‘rator 5 through a conduit 51 having a'valve 63, and may be disposed of as desired. .Due to the - relatively high proportion of incondensable gases passing through the system, it may’ often be de 40 sirable to scrub the gases from the separator 5 with a suitable solvent, for the recovery 01' vain‘ able light-‘constituents therefrom. andto‘r this 93 through a conduit I92 ‘having av valve I93, to be discharged through the conduit 99 and: an inlet 24 into'the reaction chamber 3., However, a por tion or all of the liquid collecting in the bottom‘ of the dephlegmator 93 may‘ .be withdrawn through a branch conduit I94 having a valve I95 and a pump I99, by‘ means of which this oil may be‘ delivered to the reaction vessel 92. Vapors purpose I provide a: scrubber ‘I9 having an inlet reaching the top of the- dephlegmator 93 pass through a conduit. l9‘! to the bottom of - the frac‘-‘ ‘5 as cool gas oil or other-hydrocarbon oil. The ‘tiona-ting tower 94, the interior of which is pro- v . scrubbed gases, consisting almost entirely of fixed ‘ videdwith'suitable plates or trays I99, and-in . gases and gaseous products 01’ combustion, escape which, due to the cooling eifect of the oil pass from the scrubber 19 through an outlet ‘I3 and ing through the heat-exchange coil 9‘I,'a'dephleg may be‘disposed of as desired.‘ The enriched ‘oil mating and fractionating action takes place, This‘ action is so regulated as to permit, the 1 . withdrawn through the outlet 12 may be treated .‘Hand an outlet 12 for a suitablesolvent, such - in any suitable manner for the recovery oflab sorbed ‘constituents therefrom. ' I In_1~"igu.re 1 I have also illustrated apparatus _' for employing excess heat generated within the 55 combustion chamber'ahior the purpose of effect ing a preliminary distillation or cracking of oil._ ‘for example a crude petroleum or a reduced, crude, whereby such oil ,may. be treated for, the recovery of various constituents thereof, one or recovery at‘the base of the i'ractionating tower, 9.4 oi’ a stock suitable-for cracking, for example gas oil, which isthen delivered througha valve H9 and a pump ‘III to the conduit 9! to be sup- ' plied to the coils 3t and 99. In- the latter theses ' ena heated to a cracking temperature of, for exampleirom ‘750° to 10'50° F. under a. suitable pressureof, for example,_from 59 to 1900 pounds per‘square' inch. ‘The hot cracked-products from the coil 39 pass through a transfer line H3 to _ portions of the apparatus describedhereinabove. _ the reaction vessel 92 wherevthey, mayJbe joined no‘ more of such constituents being employed in those Thus, in Figure 1, I‘have illustrated pipe coils 99,," and 32 located within ,the combustion by liquid-removed from the base of the dephleg In the reaction vessel 92 a partial _ mater ,_ 93. ' chamber I in, such manner as to‘be heated by separation into vapors and liquid occurs, the va 55 the combustion of fuel introduced in the burner. pors 'passingthrough the conduit‘ i9l_ into the _‘l. The location of the coils”, 3‘l and 92 within I dephleg‘mator 93 as stated hereinabove, while the ' the combustion chamber l is preferably such" liquid is withdrawn through a conduit H5 hav that the coil 99 is subjected to the highest heat, .ing a valve. “9 to be delivered‘through- the con coil 92 to the. lowest heat, while- coil'9l is sub-I duit 95 .on’the inlet "to thereaction vessel 3; 70 jected to an intermediate degree of- heat. The vapors and gases remaining uncondensed 70 when heavy oil or tar is to be introduced from at thetop of the fractionating tower‘ 94 pass an outside source-into the reaction chamber 3, through the vapor‘line ‘129 to a-condenser l_2l,~ it ‘may ?rst ‘be delivered by a pump 93 through ; and thence througha conduit I22 to a gas sepa a conduit 94‘to the coil 92, where it is heated to a rator 123, ‘from which liquid condensate com 7‘ temperature short of a cracking temperature, for prising naphthav or, gasoline may be removed $118388 through a pipe I253 having a valve I25. Gases manner set forth hereinabove, the introduction leave the separator I23 through a conduit I26 vof oil or tar being preferably insuiiicient amount having a valve I27 and 'may either be taken o? to reduce the temperature of the cracked gases through a branch conduit I28 having a valve I29 and vapors from a passageway I53 to, for ex _ or may be permitted to flow through the conduit ample, from 800° to 1000” F. The resultant va I25 and the inlet 23 to the vessel 3. - pors and residiual liquid maybe separately with Whenthese gases are insufficient or unsuitable drawn through valved outlets IElt and'IGS, re spectively, or may be withdrawn together for the purpose in view, additional gas may be in troduced from an outside source through a con through a valved outlet I66. In the former in- » stance, the gases and vapors withdrawn through 10 pump or fan I36 and leading to the inlets It and the conduit I66 are fractionated in the usual IQ. Various gases may be employed for this pur 7 manner while the liquid withdrawn through the outlet I65 may be ?ashed or otherwise treated to pose, such, for example, as methane, ethane, pro recover valuable constituents therefrom, while pane, butane, ethylene, proplyene and other hy in the second instance the combined gases, vapors 15 15 drocarbon gases or mixtures of these, such as nat duit I32 having a ‘valve I 33 and provided with a ural gas and re?nery gas. ' and liquids drawn through the outlet I66 may ' In general, of course, it is desired to introduce gases'containing considerable amounts of unsat urates to the vessel 3; such gas may be obtained 20' from the separator I23, especially when the cracking effected in the coil 80 and chamber 92 is'of the high temperature vapor phase type, or gas from an outside source may be employed as indicated. - i1 It will be obvious that, while I have illustrated coils 80, 8i and 82 located within the combustion chamber I, these heating coils may be located in a separate furnace if'so desired, especially where it is'desired to maintain the combustion chamber ‘I under higher pressure. Moreover, when the coils 80, M and 82 are located within the com bustion chamber I, it may be desirable to provide more heat at this point than is required for the cracking and reaction taking place‘ in the vessels 2 and 3. For the purpose of removing part of the gases of combustion leaving the combustion chamber I, the vessel 2 is provided with a stack I08 having a valve MI, whereby a suitable por _ tion of the gases reaching the top of the vessel 40. 2 may be bled on‘ to the atmosphere without being ‘permitted to pass through the chamber IS an the subsequent apparatus. - - be delivered to a separating chamber before be ing fractionated in the usual manner. In this instance, pressure of from 50 to 200 pounds or even higher maybe maintained within 20 the shell I50 and the temperatures in the com bustion chamber may vary from around 1000" F.’ to as high as 2500° F., the latter temperatures be ing desirable when times of contact of the gas or oil introduced through the, inlet I58 are ex 25 tremely short. With longer times of contact lower temperatures aproaching 1000° 1?‘. may be employed. If the oil or tar introduced through the inlet IGI is insu?cient in‘amount to accom plish the desired quenching e?ect, an additional 30 quenching medium, such for example as steam or inert gas, may be introduced along with the oil or tar through the inlet IGI. The apparatus illustrated in Figure 2 may be ‘substituted 'for that portion of the apparatus 35 shown in Figure 1 which is intended to perform the same functions, and any of the various ex pedients illustrated in Figure 1 may be employed in conjunction with the apparatus illustrated in Figure 2. For example, the residual liquid with drawn from the reaction vessel I54 may be eni ployed as a fuel or may be recycled to the inlet " ' In Figure 2, I have illustrated a modi?ed form I58. of apparatus which is especially suitable for use Furthermore, while I have illustrated in Fig 45 when very high pressures and temperatures are ‘ ure 1 a speci?c form of oil~cracking apparatus, to be employed. As shown in this ?gure, the ap it will be obvious that this apparatus may vary paratus comprises a metal shell I 5d of more or considerably in character, and that my inven tion may be employed in conjunction with many less cylindrical shape, the interior of which is di ' vided by means of a refractory liner I 5i into a 50 combustion chamber I52,-a cracking chamber or passageway I53, and a reaction chamber I 56.‘ Fuel and air are admitted to a burner I55 lo _cated in the combustion chamber I 52 through types of cracking apparatus for producing the oils or tars and gases 'to be used in my process. It will therefore be apparent to those skilled in the art that my invention is not limited to the 50 speci?c examples given hereinabove' by way of illustration, but may variously be practiced and valved inlets I 56 and I5‘I,~respectively, the ‘com 55 bustion being controlled to produce gases of com I embodied within the scope of the claims here-v bustion having a limited amount of free oxygen.’ 'inafter, made. As the gases of combustion pass from the com > ' . ‘ I claim: 7 - 1._ The process of effecting thermal conversion bustion chamber I52 into the passageway I 53, of hydrocarbons which comprises passing a hy they are brought into direct contact with a suit able hydrocarbon gas or oil introduced through drocarbon oil through a cracking zone and there 60 an inlet pipe I58 having a valve I59. A pyrolysis ' subjecting it to an elevated temperature effective or cracking of the. hydrocarbon gas or oil takes to crack said oil, separating vaporous'and resid place, resulting in the formation of unsaturated. ual conversionproducts, fractionating the vapors ' hydrocarbons, mainly of a normally gaseous to separate a gasoline fraction, 2. higher-boiling 65 character, for example, gaseous oleiins and the . fraction and uncondensed gases,‘ contacting said 65 like. The mixture of‘ cracked gases and vapors' gases with said residual conversion products at a then passes into the reaction chamber I50 where temperature of from 750° to 1100° F. in the pres it is brought into contact with hydrocarbon oil, ence of a limited amount of free oxygen, frac tionating resultant ~vaporous products of reac 70 ‘,tar” containing substantial quantities of reactive , tion to recover‘ another gasoline fraction and an constituents, this oil or tar being introduced other higher-boiling‘fraction, and delivering said through an inlet pipe ISI having a valve I62. other ‘higher-boiling fraction to said cracking such, for example, as residual oil or “pressure Within the ‘reaction chamber I56, which is pref erably provided with a ba?e It8,the cracked gases 1;. and hydrocarbon oils are caused to react in the zone for further conversion. -. " I > V 2. The'process of e?ecting thermal conversion of hydrocarbons which comprises passing a. hy 5 2,118,288 drocarbon oil through a cracking zone and therev subjecting it to an elevated temperature effec tive to crack said oil, separating vaporous and residual conversion products, fractionating the vapors .to separate‘ normally liquid constituents from uncondensed gases, contacting said gases sion of hydrocarbons which comprises passing a hydrocarbon oil to a cracking zone and there sub jecting it to an elevated temperature eiiective to crack said oil, separating the vaporous and resid ual conversion products, fractionating the ‘va pors to separate a gasoline fraction, a higher with said residual conversion products at a tem perature of from 750° to 1100° F. in the presence of a limited amount ‘of free oxygen, fractionat 10 16 20 25 30 boiling fraction and uncondensed gases,‘ contact ing said gases with cracked residual hydrocarbon oil at a temperature of from 750° to 1100° F. in ing resultant vaporous products of reaction to the presence of'a. limited amount of free oxygen, recover normally liquid products therefrom in fractionating resultant vaporous products of re cluding materials having boiling points above a action to recover another gasoline fraction and gasoline boiling point range, and delivering at another higher-boiling fraction, and delivering at least a portion of the thereby recovered normally I least a portion of said other higher-boiling frac liquid products having‘ boiling points above‘ a tion to said cracking zone for further conversion. 15 gasoline boiling-point range to said cracking zone 5. The process of effecting thermal conversion for further conversion. of hydrocarbons which comprises, passing a hy 3. The process of effecting thermal conversion drocarbon oil'through a cracking zone and there of hydrocarbons which comprises subjecting a subjecting it to an elevated temperature e?’ec hydrocarbon oil to an elevated temperature ef tive to crack said oil, separating vaporous and fective to crack said oil, separating vaporous residual conversion products, fractionally con and residual conversion products, fractionating densing the vapors to recover gasoline therefromI the vapors to separate normally liquid constitu contacting said residual conversion products with ents from uncondensed gases, cracking said gases unsaturated hydrocarbon gases at a tempera at a temperature in excess of 1300‘ F. to form ture of from’ 750°‘to 1100° F. in the presence of 25 gaseous ole?ns, contacting resultant cracked a limited amount of free oxygen, fractionating ole?nic ‘gases with said residual conversion prod resultant vaporous products of reaction to re ucts at a temperature of from 750° to 1100° F. in ,cover another gasoline fraction and another the presence of a limited amount of free oxygen, higher-boiling fraction and delivering at least a andi‘ractionating the resultant products of re portion of said other higher-boiling fraction to 30 _ action to recover normally liquid products there from. 4. The process of effecting thermal conver said cracking zone for further conversion. ‘ IIjIAROLD v. ATWELL.