US1923016A - Process and apparatus for treating hydrocarbons - Google Patents

Description

Aug. 15, 1933.

A, D. SMITH PROCESS AND APPARATUS FOR TREATING HYDROCARBNS 4 Sheets-Sheet l Filed Feb. l5, 1929 NEON .GET-OOO Aug. 15, 1933. A. D, SMITH PROCESS AND APPARATUS FOR TREATING HYDROCARBONS Filed Feb. 15, 1929 4 Sheets-Sheet 2 "1; OMA/ Flu/1501*;

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Aug. 15, 1933. l A. D. SMITH 1,923,015

A PROCESS AND APPARATUS FOR T'REATING HYDROCARBONS Filed Feb. 15, 1929 4 Sheets-Sheet 3 29 f m A [DOCK/NG FVPNM" @www1 @aM/4@ Aug. 15, 1933. A. D. SMITH PROCESS AND APPARATUS FOR TREATING HYDROCARBONS Filed Feb. 13, 1929 -4 Sheets-Sheet 4 Patented Aug. l5, 1933 PROCESS cago, Ill.,

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mpany, a Corporation of Wisconsin AND APPARATUS FOR TREATING HYDROCARBON S Arthur` D. smith, chicago, n1., Jenkins Petroleum Process Co ignor to Chi- Applieation February 13, 1929. Serial No. 339,647

Y 2 Claims. (Cl. 196-60) This invention relates to certain improvements in the treatment of hydrocarbon oils, and particularly to the method of producing high volatility anti-knock gasoline from a charging stock of higher boiling point.

In the ordinaryv liquid phase processes of converting heavier hydrocarbons into lighter hydrocarbons for the production of high volatility gasoline there are necessarily formed varying amounts.v of distillates which are not composed of sufficient light fractions to be suitable alone as a gasoline and are deficient in solvent properties. Similarly, in the ordinary liquid phase processes of cracking to produce kerosene, there are necessarily obtained varying amount of distillates which are unsuitable for burning oil because of high viscosity and unfit for ideal gas oil on account of too great volatility.

The attempt to crack these distillates in the ordinary liquid phase apparatus either separately lor by recycling with the higher boiling pointi charging stock produces unsatisfactory results since where recycling is used, these distillates are vaporized substantially without further conversion and where they are processed separately in liquid phase, large amounts of fuel are necessary and increased quantities of coke, incondensable gases and other products of low market value are necessarily formed.

An important object of this invention is the conversion into high volatility anit-knock gasoline of these distillates which are unchanged or cracked with great difficulty under the usual liquid phase methods that have been known in the art.

In my process I effect a combination of vapor phase'conversion with a liquid phase cracking process, where certain fractions of the heavier distillates from the liquid phase are conducted as they are produced to a vapor phase converter and therein cracked in vapor phase to produce a high volatility anti-knock gasoline. Furthermore, my invention comprises the combination of the apparatus in such a manner and the' process steps to be carried out in such order that there is a high vutility of the waste and residual heat which otherwise would be lost. Furthermore, my process provides for the separation of the heavier fractions of the product formed in the vapor phase conversion and the progressive conversion of a portion of these heavier fractions in vapor phase.

It is also well-known that gasoline produced by cracking in the ordinary liquid phase processes as well ras natural straight distilled gasoline is deficient in anti-knock value.

The invention includes the conversion of the previously mentioned distillates resulting from liquid phase cracking into compounds of suicient volatility and anti-knock value to permit of blending with the gasoline simultaneously formed in the liquid phase operation of this process and in the natural blended gasoline of vapor and liquid ratio formation so as to produce a phase origin and of suitable anti-knock value.

In order that Athe invention may be the more easily understood, reference is made to the accompanying d Figs. 1 and tion,

rawings, wherein the same parts wherever theyoccur.

1a are a general vertical elevain character essentially diagrammatic,

rather than showing the exact arrangement of instrumentalities, of apparatus suitable for carrying out the invention.

Fig. 2 is a plan view of a preferred arrangement of a portion of the apparatus, and Figs. 3 and 4 arevertical cross sections along the lines of Fig. 3 respectively.

Figs. 5, 6 and '7 represent minor vapor phase converter deta ils.

Referring to the drawings, 1, represents a pressure still designed for cracking' in liquid phase, comprising a horizontaldrum 2, superimposed over vertical connecting front and rear sluiceways 3 and 4, superajacent and joined to front and latter being themselves' rear cross drums 5 and 6, the

connected by the tube bank 7; the whole forming a series of freely connecting channels.

The still 1, level gauge 8, 10, leading to is further provided with a liquid safety valves 9, 9', and vapor line reflux tower 11. The reiiux line 12, connects'base of tower to rear end of still;

,the still 1 and reux tower 11 being in free open communication with each other.

Continuous plished by an shown) through line reux tower charging of the system is accomordinary high pressure pump (not 13, past check valve 14, to 11, while continuous withdrawal of a substantial portion of the degraded still contents is simultaneously eifected through line 15, as controll ed by stop valve 16, 16', 16", and

automatic relief valve 17, to low pressure vapor'izer 18; while emergency or complete discharge is afforded th rough line 19, past stop valve 20 Continuous located in rea r sluiceways 4, mounted on shaft 23, extending through stufling box 24, and operated by motor 25.

The still assembly 1, set over furnace 26, may be heated by any desirable means; the burners 27 and 27' showing a typical arrangement for oil and gas fuel respectively. The waste heat gases from the furnace 26, pass Iout through the ports 28 and 28', entering the vapor phase cracking furnaces 29 and 29'; leaving therefrom by ducts 30 and 30' to breechings 31 and 31'; thence to underground flues 32 and 32', and finally escape to atmosphere through stack 33.

The vapor. line 34 serves to conduct crude gasoline vapors from reflux tower 11, maintained at full still pressure to dephlegmating tower 35, carried at a reduced pressure; quantity of vapor flow thereto being controlled by proper manipulation of valves 36, 36', 37, 37', 38, and/or 38' (for remote regulation); or tower may be by-passed as an emergency measure by opening stop valve 39, permitting vapor to flow through line 40 and 41 direct to condenser section 42, located in water cooled condenser box 43.

The vapor line 45 serves to conduct liquid phase gasoline vapors from dephlegmating tower 35 to blending dephlegmating tower 46, or secondary dephlegmating tower 47, as may be desired; both towers being carried at less pressures than either converterq pressure and also at less pressures than the precedingr tower pressures, with inlets thereto respectively controlled by valves 48, 48', and 49, 49'; the latter permitting by-passing of vapors direct to condenser section 42 if desired.

'Vapors from secondary dephlegmating tower 47 (which may be replaced or followed by other instrumentality of refining), pass off through vapor line 41 to condenser section 42; condensate flowing to receiving tank44, from whence it is automatically discharged from system through balanced valve 50, actuated by float mechanism 50'. Receiving tank 44, together with the condensing section 42 and the dephlegmating tower immediately discharging thereto, is held at a constant pressure less than the apparatus preceding, by the gas relief valve 44', set for the desired discharge point; the waste permanent gas escaping therefrom flowing through line 51 to gas burners 27', or other point of demand.

The flow line 52 serves tol conduct condensate from dephlegmating tower 35 to reboiler 53, wherein desirable gasoline fractions are redistilled, -returning to tower through vapor line 52'; vaporization being effected by heat exchanger 53', operated by hot recycle stock vapors from low pressure vaporizer 18, discharging through vapor line 54, as controlled by proper manipulation of valves, 55 55', 55".

The flow lines 56, 56', and 57, serve to conduct the relatively light, but less preferred residual reboiler distillate, either to the cooling zone 58, or condenser section 59, by proper manipulation of stop valves 60, 60'; liquid levels being maintainedin dephlegmating tower 35 and reboiler 53, by balanced valves and float mechanisms 61, 61' and 62,V 62', respectively.

When employing condenser section 59, condensate accumulates in receiving tank 63, automatic discharge from same being controlled by balanced valve 64 and float mechanism 64'; gas pressure within receiving tank and condenser being determinedjby automatic release Valve 463'; discharging at a predetermined point to waste gas line 51.

The vapor line 54 permits the hot recycle stock vapors generated in the low pressure vaporizer 18, to perform certain additional and subsequently to be described functions, concomitant with concurrent vapor phase treatment; and nally connects with condenser section 65, from which recycle stock is ultimately discharged from the system through receiving tank 66, under balanced valve and float mechanism 67, 67' and automatic gas release control 66' which operates as in a manner previously described for condenser sections 59 and 42. This recycle stock discharged from the ,system through receiving tank 66 may, if desired, be introduced into line 13 with fresh charging stock and recycled through the system.

The stop valve 68 allows escape of fuel oil from low pressure vaporizer through lines 68' and 15 to settling tank 69, wherein carbon and spent adsorptive precipitate, and are drawn off through valve 69', clean fuel leaving system through line 69".

In eiecting vapor phase conversion, the less preferred distillate flowing to cooling zone 58, is cooled therein to a temperature just sufficient to permit effective 'action of the inspirator 70; cooling being effected through the agency of the charging stock pumped through line 13 and heat exchanger 58', as controlled by valves 71, 71' and 71". The flow line 72 feeds the inspirator 70, the` latter .discharging through line ,73, past check valve 73 to vaporizing zone 74; line 75 and valve 75', acting as inspirator overflow to cooling zone 58. rIfhe inspirator 70 is actuated by a portion of the hot high pressure gasoline vapors escaping from reflux tower 1 1, as controlled by stop valve 76, and balanced valve 77, regulated by float mechanism 77'.

Substantial vaporizaton of the less preferred distillate in zone 74, with accompanying correllated formation of pressure therein, is eiected through the agency of heat exchanger 74', with hot low pressure recycle stock vapor as the heating medium; only sufficient hot material being permitted to enter exchanger, controlled by valves 78, 78', and 78", as to continuously maintain a vapor pressure best suited for the production of a maximum quantity of anti-knock vapor phase produced gasoline, consistent with the temperature obtaining in furnace sections 79 and79, and the quantity and quality of distillate requiring conversion.

While the above discussed variants preclude a single definite pressure and temperature limitation, I employ a vapor pressure less than still pressure and preferentially about 30 lbs. while cracking at 1200 F. in converter sections 80 and 80'; the substantially vaporized distillate in zone 74, discharging through vapor line 81, past check valve 82 to converter in question, and returning through vapor'lines 83 and 84 as crude antiknock gasoline, to dephlegmating tower 85, maintained at a less pressure than converter sections 80 and 80'. While maintenance of preferred pressure in the vapor phase converter is primarily a function of controlled vaporization in zone 74, provision is also offered for regulating the pressure therein and maintaining incidentally the quantity of flow or vapor to dephlegmating tower 85, byv proper manipulation of valves 86, 86', 87, (and/or 88 for remote control); or tower may be bypassed by opening stop valve 89, thus permitting the crude anti-knock gaso- Leq ' densate from through line 112 line vapors to flow through line 83 to condenser section 90.

The vapor line 91 serves to conduct the semipreferred anti-knock gasoline vapors separating in dephlegmating tower to the blending dephlegmating tower 46, and/or to condenser section 90, through proper manipulation of valves 92 and 92'. When condensing without further dephlegmation, anti-knock gasoline, wholly of vapor phase origin accumulates in receiving tank 93, automatic discharge therefrom being con- Y trolled by balanced valve 94 and iloat mechanism 94'; gas pressure within receiving tank, suprajacent condenser section and tower 85 being determined by automatic release valve 93', discharging to waste gas line 51.

' When the vapors from tower 35 and 85 are permittedl to enter blending dephlegmating tower 46 in these natural volumes of production, the resultant light fractions pass off through vapor line 95, as controlle-d by valves 96 and 96' to condenser section 97; superior anti-knock gasoline of liquid and vapor phase origin, blended in natural formation ratio, accumulating in receiving tank 98, with withdrawal therefrom and pressure therein controlled by balanced valve 99 and fioat mechanism 99', and gas release valve 98' respectively. Provision is made for further dephlegmation (or other instrumentality of refining) of vapors from dephlegmating blending tower 46 through the valve 96'.

As condensates from towers 46 and 47 will be on the dividing line of preferred and less preerred products, provision is made through the respective agency of valves 100, 100' and 101., 101', to permit such condensates to through lines 102, 102' and 103, to condenser section 104, with subsequent discharge from system through receiving tank 105, under controls 106, 106' and 105'; or through lines 107, 107', and 108- to cooling Zone 109 for progressive vapor phase treatment. Balanced ,valves and float mechanism 110, 110 and 111, 111' respectively serve to maintain proper liquid seals in tower 46 and 47.

In effecting progressive conversion, the condephlegmating tower 85 flows to reboiler 113, wherein desirable gasoline fractions are redistilled, returning to tower through vapor line 112'; vaporization being effected by heat 'exchanger 113', operated by hot recycle stock vapors from low pressure vaporizer 18discharging through vapor line 54, as controlled by proper manipulation of valves 114, 114', 114".

'Ihe flow lines 57 and 57', less preferred reboiler distillate either to the cooling Zone 109, or condenser section 59, by proper manipulation of valves 115, 115'; liquid levels being maintained in dephlegmating tower 85 and reboiler 113,-by balanced valves and float mechanisms 116,116' and 117, 117', respectively. The less preferred distillate from reboiler A113, together with any condensate from towers 46 vand/or 47 (requiring special treatment becausel of relatively high volatility) is cooled in zonelO) just sufficient to permit effective action of the inspirator 118; cooling being effected through the agency of the charging stock pumped through line 13 and exchanger 109', as controlled by valves 119, 1192119". The ow line 120 feeds the inspirator'-118,;the latter discharging through line 121, past -fheck valve 121' to vaporizing zone 122; line 1231andl valve 123', acting as inspirator y overflow to cooligizone 109. The-inspirator 118 flow either ports 28 and 28', serve to conduct thed but identical with handle 139);

diverting (as required) the flue gases through' l rellated formation of pressure thereln, 1s effected through the agency of heat exchanger 122', with hot low pressure recycle stock vapor as the heating medium; onlysuflicient hot material being permitted to enter the exchanger, controlled by valves 126, 126', 126", as to continuously maintain a vapor pressure best suited for the production of a maximum quantity of anti-- knock vapor phase produced gasoline, consistent with the temperature obtained in furnace sections 127 and 127', and the quantity and quality of distillate requiring conversion. While the above discussed variants preclude a single definite pressure and temperature lmitation, I employ a vapor pressure less than still pressure but higher than initial vapor phase conversion pressure and preferentially about 40 lbs. while cracking at 1300D F. in converter sections 128 and 128'; the substantially vaporized distillate in zone 122, discharging through vapor line 129, past check valve 130 to converter in question, and returning through vapor lines 131 and 132 as crude anti-knock gasoline, to dephlegmating tower 85, maintained at a less pressure than converter sections 128'and 128'. While maintenance of preferred pressure in the secondary vapor phase converter is primarily a function of controlled vaporization in zone 122, provision is also afforded for regulating the pressure therein maintaining, and incidentally the quantity of secondary flow of vapor to dephlegmating tower 85, by proper manipulation of valves 133, 133', 134, (and/or 135, remote); or tower may be by-passed by opening stop valve 136, thus permitting additional crude anti-knock gasoline vapors to ilow through line 83 to condenser section 90.

In the more specific consideration of vapor phase conversion, reference will be-'made principally to Figs. 2, 3, 4, wherein the vapor phase cracking zone 29', as shown in outline in Fig. 1, is developed in detail together with its converse zone 29; it being noted that each general zone is further subdivided into the heating chambers 79', 127' and 79, 127 respectively.

The waste heat gases from furnace 26 enter the heating chambers 127 and 127', through the located at the upper rear portion of furnace walls 137 and 137'; the waste heat gases being controlled to any desired degree by proper setting of the dampers 138 and 138', operated by handles 139 and 139', (not shown the dampers :ub- hues 140 and 140 32 and 32'.

The gases entering the chambers 127 and 127', are forced to circulate around the tubular converter sections 128 and 128' (progressive vapor phase treatment), by the baille plates 141, 142, (not shown but identical with baffle plates 141', 142') and 141', 142', 'and thence pass under arches 143 and 143' to chambers 79 and 79' respectively. In like manner theegases continue their respective circulatory path by the agency of baffle plates 1'44, 145, (not shown but identical with 144', 145') and 144', 145', around th tubes of converter sections'80 and 80' (initial vapor to main` waste heat ilues atmosphere through stack 33.

The progress of the vapors undergoing vapor phase treatment is in contra-current to the waste heat circulation; the substantially vaporized distillate from zones 74 and 122 being conducted by lines 81, 81', and 129, 129', to the coolest section of converters 80, 80','and 1 28, 128' for initial and progressive vapor phase treatment, respectively. Converters 80, 128 and 80', 128', may be operated concurrently or independently by proper manipulation of valves 146, 146', 147, 147', 146o, 146o', and 14711, 147e in conjunction with flue dampers 138 and/or 138 control, as will be apparent to one skilled in the art.

The converters themselves may consist of any desired number or combination of tubular sections of freely connecting channels, arranged to produce a contra flow of vapors to the waste heat gases, a spiral course wit-hin the tubes being highly desirable. 'The converters herein illustrated each comprise two parallel rows of four tubes 148, with end members provided with box elbows 149, manifolded together by yoke piece 149'; the intermediate tubes being connected to end members and each other by top and bottom return bends 150 and 150', respectively. The box elbows 149and top return bends 150 are provided with single, and the bottom return bends 150', with double removable plugs 151 for cleaning purposes. The converter vsections themselves are hung from suitable supports to permit of free expansion, and the pits 152 and 152 permit of such rerolling of tubes as may be required as shown in Fig. 4 with reference to converter 80'.

A spiral circulatory course within the tubes 148 may be produced `by.insertirig therein the .freely fitting helicoidal flights 153 mounted on shafts 153', as shown in Figs. 5 and 6. The shafts may terminate within the return bends and be provided with-eye-bolts 154 to facilitate removal for cleaning purposes as is shown inv Fig. 5; or the shafts may extend through stuifing boxes 154 fitted in plugs 151, and provided with handles 155, as is illustrated in Fig. 6; the latter construction permitting of rotation of ights with substantial scraping effect without removal of plugs.

The crude gasoline vapors formed in the converters 80, 80 and 128, 128 are conducted by the lines 156, 156' and 157, 157 to the vapor phase cooling zones 158 and 159 respectively; such zones being equipped by safety valves 158 and159, and maintained at temperatures just sullieient to precipitate any high molecular Weight polymerides or tarry complexes, through the agency of the charging stock pumped through line 13 as a cooling medium. Control of vapor temperatures within the zones 158 and 159 is respectively effected through proper manipulation of valves 160, 160', 160 and 161, 161', 161, in conjunction with by-pa'ss lines 162 and 162'.

The slightly cooled crude gasoline vapors in zones 158 and 159 flow through lines 163 and 164 terminating in centrifuge nozzles 163 (Fig. '7) and 164', to the separatory drums 165 and 166 respectively; wherein the objectional condensates separate out and--may be continuously drawn off through the'valves 165' and 166' to the line 167, which line connects with main fuel V gauges, both indicating and recording, are installed according to requirements, and relief and safety valves not designated in the description or shown in the accompanying drawings may be utilized as one familiar with the art would naturally employ. The process may be carried out as follows: Charging stock of higher lboiling point oil is continuously pumped through line 13 through heat exchangers in cooling zones 58 and 109, through heat interchangers in vapor cooling zones 158 and 159 and then into the top of re- .fiux tower 11 and from there into still 1 .in which it is cyelically circulated and cracked in liquid phase. The vapors from still 1 pass through line 10 into reflux tower 11 and the gasoline fractions including certain heavier fractions pass from reflux tower 11 into line 34 and a portion of this distillate is discharged into dephlegmating tower 35 where the heavier fractions are dephlegmated from the gasoline fractions by means of the tower and reboiler 53. The heavier fractions of this liquid phase distillate accumulate in reboiler 53 and are conducted from the bottom thereof into cooling zone 58 which is cooled byl heat' interchange with the charging stock as previously described.

The lcooling zone is under a lower pressure than the dephlegmating tower 35 and the liquid is forced from this cooling zone into vaporizer zone '74 by means of an aspirator which is operated by a portion of the vapors from reflux tower 11. These heavier fractions which have been separated from the gasoline vapors are now vaporized in vaporizing zone 74 and from there are released through line 81 into the outer or initial vapor phase converter coils. These initial vapor phase converter coils are arranged on the outside of a set of vapor phase 'coils used for the progressive vapor phase conversion, the vapor phase coils being arranged in pairs and disposed laterally on each side of the tubes of the liquid phase apparatus so as to be successively heated by the furnace gases therefrom. The initial vapor phase converting coils being more'remote in the path of the waste heat gases are at a lower temperature than the progressive vapor phase converting coils and the coils are so arranged that the oil passes therethrough in counter-current to the path of the waste heat .furnace gases as will be readily ascertained from Figure 3.

The converted vapors pass from the initial vapor phase converter into vapor cooling zone 158, the cooling being sufdcient merely to cause complex polymerides and tarry substances produced in the cracking operation to be more readily separated by being passed through centrifugal nozzle 163', the heavy substances being drawn off through line 167 and the converted vapor phase gasoline vapors including some heavier vapors pass off through line 83 to dephlegmating tower 85. l The heavier fractions are separated from the gasoline fractions in dephlegmating tower 85 by means of the tower and reboiler 113 and these heavier vapor phase fractions are treated in the same manner as are the heavier liquid phase fractions, being passed successively through a cooling zone and'thence into a vaporizing zone from which they are conducted into the progressive vapor phase converter where progressive vap'or phase cracking occurs. The vapors from this progressive vapor phase converter are partially cooled, centrifuged, the tarry substances removed and the vapors conducted through line 131 to dephlegmating tower 85, any heavier vapors which have not been suliciently cracked being separated therein and returned for-further progressive phase cracking. From the liquid phase cracking still degraded material is constantly Withdrawn into low pressure vaporizer 1,8 where vthe pressure is reduced, the heavy substances being withdrawn from the system lthrough the settling tank 69 and the vapors from low pressure vaporizer 18 being passed in heat interchange through the vaporizing zone 122, reboiler 113, vaporizing zone 74 and reboiler 53 and then are condensed in 65 and may be recycled with fresh charging stock through 13.

The vapor phase gasoline fractions from dephlegmating tower 85 are conducted through line 91 to blending tower 46. The liquid phase gasoline fractions are conducted vfrom dephlegmating tower through line 45 to blending tower 46. The blended product, an anti-knock gasoline of vapor phase and liquid phase origin, is

conducted through line 95 from blending towerI 46, condensed in 97 land withdrawn from the system. Further blending may occur when desired by conducting a portion of the liquid phase gasoline from dephlegmating tower 35 to the secondary blending tower 47 and conducting a K portion of the blended gasoline from tower 46 into the secondary blending tower 47. Thus blending of the liquid'and vapor phase gasoline fractions occurs in their natural ratios in tower 46 and may occur in any selective ratio in tower 47. The heavier fractions dephlegmated from the blending gasoline vapors in towers 46 and 47 are returned through line 108 to cooling zone 109 and is there mixed with the heavier fractions from dephlegmating tower 85 to be treated. in thevprogressive vapor phase converter.

By means of the heat interchange system herein described, the heavier distillates of vapor and liquid phase origin are independently cooled to temperatures permitting efficient action of the aspirators or injectors and these distillates after also provid cooling', are removed from their cooling zones to zones of higher pressure wherein they are vaporized before being subjected to vaporphase conversion treatment. The converted vapors from the vapor phase converter are passed through cooling zones of slightly lower tern perature, but ofsubstantially the same respective pressures as the vapor phase cracking zones, wherein any tarrycomplexes ofhigh molecular weight polymerides assume a vaporized or semiliquid condition; then through separating zones of the same pressure and temperature'as the respective cooling zones wherefrom such tarry complexes and polymerides are continuously vrevmoved; and finally to an intermediate dephlegmating zone or bubble tower, maintained at a less pressure thaneither of the crackingzones. The gasoline fractions from the liquid phase and vapor phase operations are. blended in a substantially vaporous state and in the natural ratios of j.- 'tlieir respective formations in the process. Fu'rtherblending in any selective ratio is for in the process. In brief, 'thlsprOQsS involves the production by liquid. phase treatment; the dephlezmatlon of said crude gasoline into lighter and heavier fractions, the transfer and substantial vaporization of said heavier fractions through the'waste energy of said liquid phase treatment; the subjection of said vaporized fractions to vapor phase cracking through the agency of the cooler waste heat from said liquid phase treatment; the dephlegmation of the crude vapor gasoline into -higher and heavier fractions, the progressive vapor phase treatment of said heavier fractions through the agency of the hotter waste heat from said liquid phase treatment; the dephlegmation of the blended fractions of liquid and vapor phase cracking; the production of anti- -knock gasoline and of heavier fractions as solvents of materials for further progressive vapor phase cracking.

The invention is further not limited to the type or arrangement of the instrumentalities above described, and what I claim is new and desire to protect by Letters Patent is:

1. A method of converting hydrocarbon oils into anti-knock gasoline which comprises subjecting hydrocarbon oils to a cracking temperature under pressure for a time suiiicient to crack said oils in the liquid phase and evolve vapors therefrom, separating vapors so evolved from unvaporized hydrocarbon oils, conducting a portion of said vapors to a dephlegmating zone and therein separating out heavier fractions from said vapors as a condensate, retaining separate and substantially revaporizing said condensate, thereafter subjecting the resulting vapors to a cracking temperature for a time suilcient to crack said vapors in the vapor phase, removing vaporized oil products from said vapor phase cracking reaction to a fractionating zone, commingling therein vaporized oil products from a second vapor phase cracking reaction independent of said first-mentioned vapor phase cracking reaction, separating out heavier fractions as a condensate from saidcommingled products to obtain anti-knock gasoline vapors, retaining separate and substantially revaporizing said condensates of heavier fractions, and thereafter subjectingthe resulting vapors to said second vapor phase 'cracking reaction.

2. An apparatus for converting hydrocarbon oils into anti-knock gasoline which includes a furnace, tubularheating means-Within said furnace. for convertnig said hydrocarbon oils in liquid phase, a vapor separating means connected to said tubular heating means, a second tubular heating means within said furnace for converting hydrocarbon oils in vapor phase, a reflux tower connected to said vapor separating means, a dephlegmator connected to said reflux tower, a vaporizing chamber in communication with the bottom of said dephlegmator, an injector between said dephlegmator and said vaporizing chamber in communication therewith for transferring condensates from said dephlegmator to said vaporiging chamber, a vapor line from said reflux tower communicating with said injector for actuation thereof by hot vapors from said reux'tower, a vapor conduit con-l necting said vaporizing chamber and said vapor phase tubular heating means, and a dephlegmator in communication with said vapor phase tubular heating means.

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