US2270071A

US2270071A - Hydrocarbon conversion

Info

Publication number: US2270071A
Application number: US292848A
Authority: US
Inventors: Edwin H Mcgrew
Original assignee: Universal Oil Products Co
Current assignee: Universal Oil Products Co
Priority date: 1939-08-31
Filing date: 1939-08-31
Publication date: 1942-01-13
Anticipated expiration: 1959-01-13

Description

Jan. 13, 1942. l E. H. McGREw Y HYnRoCARBoN coNvERsIoN Filed Aug. 31, 1939 m 1---.@ mM WH.

, E 5% XS w AORY Patented riant. i3, i942 nroaocannou ooNvnnsioN Edwin H. McGrew, Chicago, lill., assigner to Univer-sai @il Products Company, Chicago, lil., a

corporation of Delaware application .august 3i, i939, serian No. 292,848 9 claims. lol. 19t-49) This invention relates toa process for converting hydrocarbon oils into substantial yields of gasoline of high octane rating, relatively low olefin content, and low potential gum content. More speciiically, it relates to a process involving a series of individual cooperative steps combined in a novel and advantageous manner so that each of several types of hydrocarbon oils treated are subjected to the optimum conditions for the production of motor gasoline.

The invention involves principally thermal cracking treatment of a relatively heavy hydrocarbon oil, such as, for example, reduced crude oil, with concurrent thermal cracking treatment of the recycle obtained therefrom, thermal reforming treatment ci' a relatively light hydrocarbon oil, such as, for example, gasoline, naphtha, or kerosene, common fractionation of the conversion products from the thermal cracking and reforming treatments, high temperature catalytic cracking treatment of an intermediate oil, such as gas-oil, and low temperature catalysis of the gasolines produced in the thermal crack.- ing and reforming treatments, and high temperature catalytic cracking treatment in com-` mingled state with light 'reflux condensate formed in the thermal cracking treatments to produce a gasoline of high octane rating and relatively low oleiin content.

The term thermal cracking treatment as used throughout the present speciiication and claims refers to the conversion of heavy hydrocarbons into lighter hydrocarbons by heat and pressure, and in all instances involves the scission of carbon to carbon bonds. The term "thermal reforming treatment, on the other hand, refers to the treatment of relatively light hydrocarbons to improve their octane rating and may involve the scission of carbon to carbon bonds, `the scission of carbon to hydrogen bonds, cyclization, and many other reactions of lesser importance. The term high temperature catalytic cracking treatvment refers .to the treatment of hydrocarbon oils in the presence of catalytically active materials at temperatures ranging, for example,-

from 300 to 1200 F. and at pressures varying from substantially atmospheric to 200 pounds or .more per square inch to effect substantial conversion to gasoline boiling range hydrocarbons, and ordinarily involves the scission of carbon to carbon bonds, although other reactions such as cyclization and the scission of carbon to hydrogen bonds may also take place. The term low ternperature catalysis" refers to the treatment of hydrocarbons at relatively low temperatures ranging, for example, from 500 to 900 F. and at pressures ranging from substantially atmospheric to 200 pounds or more per square inch in the presence of a 'catalyst'of essentially the same composition as that employed in the high temperature catalytic cracking treatment, and the principal reactions involved are essentially hydrogen rearrangements.

The gasolines from thermal cracking, thermal reforming, and high temperature catalytic cracking usually contain a relatively high percentage of olenic hydrocarbons which, although tending to improve the octane rating, are potential gum formers. The acid heat test of gasolines containing relatively high percentages of olefinic hydrocarbons, in addition, is generally high while the susceptibility to 'added antiknocking agents is relatively low, thereby rendering gasolines produced in such processes unfit for aviation purposes. Gasolines rich in paraiiinic hydrocarbons, preferably containing high percentages of isomeric paraiiinic hydrocarbons, and in some instances containing aromatic hydrocarbons, on'

the other hand, are particularly useful as an aviation fuel because of the` relatively low acid heat test and good susceptibility to added antiknocking agents, such as tetraethyl lead.

It has been found that when the olefin-containing gasolines produced by' non-catalytic and high temperature catalytic cracking methods are subjected to contact with a catalyst of essentially the same composition as that employed in the catalytic cracking treatment but at lower space velocities and lower temperatures with light recycle from a non-catalytic cracking treatment, a substantially saturated gasoline product is obtained. Whereas, in high temperature catalytic cracking treatments temperatures on the order of 800 to 1200 F, are employed with pressures of from substantially atmospheric to 200 pounds or more per square inch with space velocities of from 2 to 6 volumes of liquid hydrocarbon material per volume of catalyst per hour, in the low temperature treatment temperatures on the order of 500 to 900 F. are employed with pressures of from substantially atmospheric to 200 pounds or more per square inch and with spacevelocities of from .5to 2.

The reactions involved in the low temperature treatmentare essentially those of transferring hydrogenfom the heavier hydrocarbons to the lighter .olenic hydrocarbons to form paraiiinic urated hydrocarbons and particularly the naphthenic hydrocarbons of the recycle oil act as hydrogen donors to the oleiinic hydrocarbons of the gasoline, while the olefinic hydrccarbonsbecome saturated to form aliphatic hydrocarbons and the naphthenic hydrocarbons are converted to aromatic hydrocarbons. Various other reactions, such as, for example, dehydrogenation and cyclization of an aliphatic hydrocarbon to form an aromatic hydrocarbon with the formation of two or three molecules of hydrogen which attach to the unsaturated oleiinic hydrocarbons may also take place. However, since the invention is concerned primarily With a process in which the various reactionsmay be conducted, further discussion with regard tc the chemical reactions which may possibly be involved is unnecessary for a' full understanding of the invention, which is to be described in more detail later.

In one specic embodiment the invention comprises subjecting a relatively heavy hydrocarbon oil to thermal cracking treatment in a heating coil, concurrently subjecting reux condensate, formed as hereinafter described, to thermal cracking treatment `in a separate heating coil, commingling the hot conversion products from the last mentioned heating coil with those from the rst mentioned heating coil and supplying the mixture to a communicating reaction chamber to effect substantial further conversion thereof, subjecting a relatively light hydrocarbon oil to thermal reforming treatment in a heating coil, commingling the conversion products from said thermal reforming treatment and the conversion products from said reaction chamber sind -supplying the commingled material to a vaporizing and separating chamber to separate a nonvaporous liquid residue from the vaporous conversion products, recovering the former, supplying said vaporous conversion products to a iractionator to separate by fractionation the gasoline boiling range materials from the higher boiling components, condensing the latter as light and heavy reflux condensate, supplying said heavy reflux condensate to the second mentioned heating coil, for treatment as aforesaid, simultaneously with the thermal cracking and thermal reforming treatments, heating and vaporizing a mixture comprising essentially an oil boiling intermediate to the two first mentioned charging oils and reflux condensates formed in the subsequent high and low temperature catalytic treatments, subjecting the heated vapors to contact with a catalyst mass in a high temperature catalytic cracking zone, fractionating the vaporous conversion products from said high temperature catalytic cracking zone to separate gasoline boiling range materials from the higher boiling components, condensing the latter as reflux condensate and subjecting it to high temperature catalytic treatment as aforesaid, commingling the gasoline boiling range materials from the thermal cracking and reforming treatments and thehigh temperature catalytic cracking' treatment with saidy light reflux condensate, heating the lmixture and supplying the heated mixture to contact with a catalyst in al low` temperature catalytic zone, fractionating the conversion products from said low temperature catalytic zone to separate fractionated vapors of the de'sired end boiling point from the higher boiling hydrocarbons, recovering said fractionated vapors as a product of the'process. condensing said higher boiling hydrocarbons as reflux condensate and subjecting the latter to high temperature catalytic treatment as aforesaid.

The accompanying diagrammatic drawing shows in conventional side elevation one specic form of the apparatus in which the object of the invention may be accomplished. It is to be understood that the invention is not limited to the use of the speciiic form of apparatus herein shown and that various forms of apparatus herein described may be used Without departing from the broad scope of the invention.

Referring now to the drawing, a relatively heavy hydrocarbon oil, such as, for example, a topped or reduced crude oil, is introduced through line I and valve 2 to pump 3, which discharges through-line 4 and valve 5 into heating coil E. The oil in passing through heating coil 0 is raised to the desired cracking temperature, which may range, for example, from 800 to 950 F. and is `maintained at this temperature for a sufficient period of time so that substantial cracking may be eiected, the heat necessary to raise the oil to the desired temperature and to furnish the heat oi. cracking being supplied by furnace l. The hot conversion products leave heating coil 6 through line 8 at a super-atmospheric pressure ranging, for example, from 200 to 600 pounds or more per square inch and are directed through Vvalve 0, commingled with other hot conversion products formed by cracking heavy reiiux condensate, as hereinafter described, and the mixture thereafter introduced to reaction chamber I0 wherein it is subjected to prolonged conversion at the cracking temperature. Reaction ychamber I0 is preferably operated at a superatmospheric pressure substantially the same as treatments being accomplished ir heating coils 6 and 33, a relatively light hydrocarbon oil, such as, for example, gasoline, naphtha, ory kerosene, or any mixture thereof, is introduced through line Il and valve I5 to pump I6, which discharges through line I'I and valve IB into heating coil I9. VThe oil in passing through heating coil I9 is subjected to thermal reforming treatment at a temperature ranging, for example, from 950 to 1050 F. by means of heat supplied from furnace 20. The conversion products leaving heating coil I9 at a pressure ranging, for example, from 500 to 1200 pounds or more per square inch are directed through line 2| and valve 22 to line II where they commingle `with the vaporous and liquid conversion products from reaction chamber I0.

Vaporizing and separating chamber I3 is preferablyoperated at a reduced pressure relative to that employed in reaction chamber I0 and may range, for example, from 50 to 250 pounds or more per square inch. The liquid `conversion products are subjected to substantial further vaporization to form a non-vaporous liquid residue. the latter being withdrawn from chamber I3 by way of line 23 and valve 24 and directed to cooling and storage or to further'treatment as desired.

The vaporous conversion products separated in chamber I3, together with the vapors evolved aaropn therein, are directed through line 2d and valve 26 into fractionator 2 which is preferably main tained at a superatmospheric pressure of ,the same order as that employed in chamber I3. The vaporous conversion products introduced to fractionator` 2l are subjected to fractionation therein to form light and heavy reflux condensate and to separate fractionated vapors which may comprise gasoline boiling range hydrocarbons or may, when desired, include hydrocarbons boiling above the range of gasoline. condensate is directed through line 2t and valve 2d to pump 3d, which discharges through line 3l and valve 32 into heating coil S3. The heavy reflux condensate in passing through heating coll 33 is raised to the desired cracking temperature which may range, forexample, from 900 to l030 F. and is maintained at the cracking temperature for a suicient period of time to effect substantialV conversion thereof. The conversion products leaveheating coil 33 at a substantial superatmospheric pressure which may range from 400 to 800 pounds or more per square inch and are directed through line 35 and valve B into line E for treatment as previously described.

Fractionated vapors separated in fractionator 2 are directed from the upper portion thereof through line 31 and a portion corresponding to the amount required for cooling and reiiuxing fractionator 2 is directed through valve 38 to cooling and condensation in condenser 39, the residual portion =being directed through line ld and valve di into line Sl, for treatment as hereinafter described. If, on the other hand, it is desirable to subject all of the fractionated vapors to cooling and condensation, valve il in line d@ ,may be closed and all of said fractionated vapors directed through valve 38 to cooling and condensation in condenser 39. In any case, the distillate from condenser 39, together with undissolved and uncondensed gases, is directed through line 42 and valve d3 to receiver dd, wherein the normally liquid hydrocarbons are separated from the undissolved and uncondensed gaseous hydrocarbons, the latter being Vwithdrawn from receiver d by way of line i5 and valve 436. When the distillate collected in receiver M is to be used solely for cooling and reuxing in fractionator 2l, all of it may be withdrawn therefrom, by well known means not shown, and introduced into the upper portion of fractionator 2l. On the other hand, it may be vdesirable at times to recover a portion or al1 of the distillate not required for reiiuxing in fractionator 21, and this may be accomplished by withdrawing the distillate through line ll and valve 48. The preferred method, however, and one more in accord with the object of the invention, ls to direct the distillate not employed as a refiuxing and cooling medium through line 9 and valve 50 to pump l, which discharges through linel 52 and valve 53 into line 97, for treatment as hereinafter described.

Concurrently with the thermal cracking and reforming treatments an intermediate oil, such as, for example, kerosene or gas-oil, isv introduced through line 56 and valve 55 into pump lE56, which discharges through line 5l andl valve 5d and the oil commingled, when desired, with reiiux condensate formed as hereinafter described. in any case, the hydrocarbon oil in line 5l is directd The heavy re'ilux e precipitation as hydrogels.

cracking thereof, the heat being supplied from furnace de. The heated vapors leaving heating coil 5d at a pressure ranging, for example, from substantially atmospheric to Zilli pounds or more per square inch are directed through line t! and valve S2 into reactor d3 wherein the vapors are subjected to contact with a cracking catalyst disposed therein while maintaining the hydrocarbon vapors at substantially the same tcm perature as that employed on the outlet or the heating coil by means of heat supplied from an external source. f

The preferred cracking catalystsv for use in the present process consist in general of a precipitated alumina hydrogel and/or zirconia hydrogel composited with silica hydrogel, the gel composite being washed, dried, formed into particles and calcined to produce a catalytic mass. It is not intended, however, that the process should` be limited to these particular catalysts, for other catalysts, such. as, for ex.

ample, the hydrosilicates of alumina, acid treated clayaand the like, may be used'within the broad scope of the invention.

In the following specication and claims the terms silica, alumina, silica-zirconia, and silicaalumina-zirconia masses are used in the broad Vsense to designate the synthetic composites referred to above. The preferred catalysts may be prepared by precipitating silica from a solution as a hydrogel within or upon which the alumina and/or zirconia are deposited also by The silica hydrogel i may conveniently be prepared' by acidifying an (ifi into heating coil 59 wherein it is substantially completely vaporized and raised to the desired temperature which may range, for example, from 800 to 1200 F. without substantial pyrolytic aqueous solution of sodium silicate by the addition of a required amount of hydrochloric acid. After precipitating, the silica gel is preferably washed `until substantially 'free from alkali metal salts. The washed silica hydrogel is then suspended in a solution of alumina and/or zirconium salts and an alkaline precipitant, such as am monium hydroxide, ammonium carbonate or ammonium suliide added to the solution to precipitate aluminum and/or zirconium hydrogels.

.'I'he nal precipitate, comprising essentially hydrated silica and hydrated alumina and/or zirconia, is washed to substantially completely remove water soluble materials and dried at about 300 F. to produce a rather crumbly and granular material which may be ground and pelleted or sized to produce particles of catalyst after which the catalyst particles are calcined at a temperature in the approximate range of 1000 to 1500 F. Various other procedures, such as, for example, co-precipitation of the hydrated gels may be employed, when desired, to ,produce the preferred catalyst.

Reactor 531s preferably of the type which employsl a plurality of relatively small diameter reactor tubes containing the desired-catalyst, the tubes being confined within an enclosed zoneto which heat from an external source may be supplied for the purpose of maintaining the reactants at the desired temperature during the conversion reaction. Y In addition', since relatively short periods of operation are employed in catalytic cracking-because of the rather rapid deposition of carbon upon the surface and within the pores of the catalyst particles which necessitates frequent reactivation, it is preferred that a plurality of reactors be employed, although only onev is shown in the drawing, in order that Vone or.

complished in the other or others. Suitable means, not shown, may be employed for reactivating the catalyst disposed within the various reactors during the period'those particular reactors are segregated from the balance for the purpose of reactivation.

Although. the reactor described above constitutes the preferred type of reactor, it is not intended that the invention should be limited in this respect, for various other types of reactors, known to those in the art, may be substituted. therefor without departing from the broad scope of the invention.

The conversion products leaving reactor 53 are directed through line |54 and valve S5 into separating zone El which forms the lower portion of fractionator and separator 66. Fractional-tor and separator E56 is preferably operated at a superatmospheric pressure substantially the same as that employed on the outlet of reactor t3. porous liquid residue separated from the vaporous conversion products in zone 57 is withdrawn from the lower portion thereof by way of line |26 and valve |21, cooled and recovered or subjected to any desired further treatment. Vaporous conversion products separated in zone l are directed through separating tray E9 into fractionating zone 68 wherein they are subjected to fractionation to form reflux condensate and to separate fractionated vapors of the desired end boil- Reflux condensate formed within fractionating zone t8 is directed from the lower portion thereof through line 'lll and valve 7| into pump 62. Pump i2 discharges through line I3 and a portion or all of the oil may be directed through line 14 and valve l5 and recovered as a product of the process. However, since reflux condensate produced in this manner is more valuable as a potential source of gasoline, the preferred method is to subject it to further cracking treatment either by catalytic or non-catalytic methods. When the reflux condensate in line 'i3 contains relatively high percentages of aliphatic hydrocarbons as compared to the concentration of aromatic hydrocarbons, the desired treatment would be to crack it in the presence of a catalyst, in which case the reflux condensate in line 'I3 would be directed through valve 1G into line 51, commingled therein with the intermediate oil and thereafter subjected to treatment as previously described.I If, on the other hand, the reflux condensate contains relatively high percentages of aromatic hydrocarbons, the more desirable treatment would be cracking by non-catalytic means, in which case the oil in line '|3 would be directed through line Tl and valve 78 into line 3|, commingling therein with heavy reflux condensate, formed as previously described, and the mixture subjected to thermal cracking treatment in heating coil 33.

Although the above described procedures are the two preferred ones, it may be desirable, de pending upon the type of operation employed, to introduce portions` of the reflux condensate in line 'I3 to both high temperature catalytic cracking treatment and the thermal cracking treat-- ment simultaneously.

Fractlonated vapors separated in fractionatingy Non-vaaarden and condensation in condenser 8 I. Distillate. together with undissolved and uncondensed gases in condenser iii, is directed through line 82 and valve B3 into receiver 8d wherein the distillate and undissolved and uncondensed normally gaseous hydrocarbons are collected and separated. Normally gaseous hydrocarbons separated in receiver ili are directed from the upper portion thereof through line 85 and valve 86 and co1- lected or subjected to any desired further treatment. A portion of the distillate collected and separated in receiver 34 is returned to the upper portion of fractionating zone t8, by well known means not shown, as a refiuxing and cooling medium therein. When desired. the balance of the distillate collected and separated in receiver 8d may be recovered as a product of the process by withdrawing the same through line 8l and valve B8. The balance of the distillate collected in receiver lill, however, preferably and in accordance with the object of the invention, is subjected to further catalytic treatment in order to produce the gasoline which is substantially free of oleflnic hydrocarbons. The balance of the distillate collected in receiver 84 may therefore be directed through line 89 and valve 90 to pump 9i, which discharges through line 92 and valve 93 into line 9i' for treatment as hereinafter described.

Light reflux condensate from fractionator 2l is directed through line 94 and valve 95 to pump 96, which discharges through line 97 and valve 98, the light reflux condensate commingling therein with the distillate separated in fractionator 2l and fractionator and separator 66, the mixture thereafter'being supplied to heating coil 99. In some instances, depending upon the volume of saturated gasoline which may be used economically, it may be desirable to subject only one or portions of the separately formed distillates, in which case the other distillate or portions may be recovered as products of the process.

The oil introduced to heating coil 99 is raised to a temperature in the range of 500 to 900 F. without substantial pyrolytic cracking thereof by means of heat supplied from furnace |00. The heated oil leaving heating coil B9 at a pressure ranging, for example, from substantially atmospheric to 200 pounds or more per square inch is directed through line |Ii| and valve H32 into reactor |U3 where it is subjected to contact with a cracking catalyst while maintaining the cil at substantially the same temperature as that employed on the outlet of heating coil 99. The catalyst employed in reactor |03 may be of the same composition as that employed and described in connection with reactor 63. The low and high temperature catalytic reactions differ essentially with respect to temperature and contact Limes employed, the reaction in reactor 63 being carried out at a relatively high temperature and short contact time, whereas the reaction in reactor |03 is carried out at a lower temperature and at a longer contact time. Reactors 63 and |03 may be essentially of the same design, however, as was previously mentioned, various other types of reactors may be employed to accomplish the desired results.

The conversion products leaving reactor |03 are directed through line |M and valve |05 into fractionator |06 and maintained at substantiallyr the same or at a reduced pressure relative to *hat employed on the outlet of reactor |03. The conversion products introduced to fractionator |06 are subjected to fractionation therein to form reflux condensate and to separate the gasoprocess.

Pump 09 discharges through line H0 and a portion or all oi the reflux condensate may be re- 'covered as a product of the process by withdrawing the same through line Iii and valve H2. Reux condensate formed in fractionator 06, however, 'is more advantageously utilized by subjecting it-to further cracking treatment and preferably to the high temperature catalytic square inch. The conversion products from the reaction chamber and the last mentioned heating coil were commingled and the mixture introcracking treatment because of its relatively high hydrogen content as compared to the reflux condensate formed in the high temperature catalytic cracking treatment. .This may be accomplished by directing the reflux condensate in line H0 through valve M3 into line i3 commingling with the reflux condensate formed in fractionating zone 68, the mixture thereafter being introduced to line 5l for treatment as previously described. In some instances, however, it may be desirable to subject a portion or all of the reflux condensate from fractionator ill to thermal cracking treatment, in which case it maybe directed through line lill and valve H5 into line 3i, cornmingling therein with the heavy reux condensate from iractionator 2l, the mixture thereafter being supplied to heating coil 33 for treatment as previously described.

Fractionated vapors from fractionator 00 -are directed through'line H0 and valve H1 to cooling and condensation in condenser H8. Distillate,

together with undissolved and uncondensed gases from condenser H8, is directed through line H9 and valve E to collection and separation in balance of the distillate collected in receiver klli Vduced to a vaporizing and separating chamber maintained at a superatmospheric pressure of 75 pounds per square inch wherein vaporous conversion products and vapors formed due to the reduction in pressure were separated from the non-vaporous liquid residue and the latter recovered as a product of the process. The vapors introduced and evolved in the vaporizing and separating chamber were introduced to a fractionator operated under a superatmospl'ieric pressure substantially the same as that maintained in the vaporizing and separating chamber to separate by fractionation high boiling components from the vapors boiling below 400 F. and to form light and heavy reflux condensate from said higher boiling components, the heavy reflux condensate being subjected to thermal cracking treatment, as previously described.

is removed therefrom by'way of line l2@ and valve 25 and recovered as a product of the As an example of one specio operation of the process a's it may be accomplished in an apparatus such as illustrated and above described is approximately as follows:

A 25 A. l?. I. gravity Mid-Continent reduced crude oil was subjected to thermal cracking treatment in a heating coil at a temperature of 890 F. and at a superatmospheric pressure of 300 pounds per square inch.l Concurrently, heavy Ireflux condensate, formed as hereinafter set forth, was subjected to thermal cracking treatment in a separatel heating coil at a temperature of 940 F. and at a superatmospheric pressure of 500 pounds per square inch. The hot conversion products was subjected to prolonged conversion at the elevated temperature.

Substantially simultaneously, a 25 A. P.) I.

" gravity hydrocarbon oil fraction, comprising lstraight-run gasoline, naphtha, and kerosene, was

subjected to thermal reforming treatment in a heating coil at a temperature of 1010v F. and at a'superatmospheric pressure of 'X50- pounds per from both heating coils were commingled and the Fractionated'vapors were cooled and condensed and the resulting distillate and gas collected and separated.

In another step of the process a A, P. I.

were subjected to contact with a silica-aluminazirconia catalyst at a superatmospherlc pressure of approximately pounds per square inch while maintaining the vapors at substantially the same temperature as that employed on the outlet of the heating coil. The conversion products in this case were introduced to a separating zone operated at a superatmospheric pressure substantially the same as that employed on the outlet of the catalytic conversion zone to separate a non-vaporous liquid residue from the vaporous conversion products, the former recovered as a product of the process, and the vaporous conversion products subjected to fractionation to form reux condensate and to separate as vapors .hydrocarbons boiling below 400 F. The reflux ycondensate was returned to the heating coil for :further conversion while the fractionated vapors were subjected to cooling and condensation and the resulting distillate and gas collected and separated. i

The distillate separated in the thermal and catalytic cracking steps were commingled with the light reux condensate formed in the first mentioned fractionator, the mixture heated to a .temperature of approximately 750 F. and thereafter subjected to contact with a cracking catalyst-in a low temperature conversion zone at a pressure of approximately 100 pounds per square inch. The conversion products from the low temperature conversion zone were introduced to a fractionator operated at a superatmospheric pressure substantially `the same as that employed on the outlet of the conversion zone wherein the heavier components were separated by fractionation from the vapors boiling below 300 F. and the former condensed as reiiux condensate in the fractionating zone. The reflux condensate from this zone was supplied to the heating coil of the highv temperature catalytic cracking treatment while the fractionated vapors were subjected to proximately 69% of 300 F. end point gasoline having an octane rating of 78 and a bromine number of 7. With the addition of 6 cc. oi tetraethyl lead the octane rating was raised to 91. in addition, approximately 14% of non-vaporous liquid residue was obtained with an A. P. I. gravity of l0, the balance being attributed principally to gas and loss.

l claim as my invention:

1. A process for the conversion of hydrocarbon oils to produce gasoline containing a relatively small amount of olenic hydrocarbons, which comprises subjecting a relatively high boiling hydrocarbon oil to thermal cracking treatment, concurrently therewith subjecting a relatively low boiling hydrocarbon oil to thermal reforming treatment, commingling the conversion products and fractionating to form light and heavy reflux condensate and to separate vapors boiling in the range of gasoline, simultaneously in another step of the process subjecting an oil boiling intermediate to the two rst mentioned oils to high' ilux condensate from said thermal cracking treatment, and subjecting the mixture to the action of a cracking catalyst at a temperature of about 50o-900 F. for a suicient time to effect substantial saturation of the olen content of the gasoline, said -process being further characterized in that vapors boiling in the range of gasoline from the thermal cracking treatment are commingled with the distillate from the high temperature catalytic cracking treatment and the light reux condensate from the thermal cracking treatment without prior cooling and condensation thereof.

2. A process for the conversion of hydrocarbon oils to produce gasoline containing a relatively small amount of oleiinic hydrocarbons, which comprises subjecting a'relatively high boiling hydrocarbon oil to thermal cracking treatment in a heating coil, concurrently therewith subjecting heavy reflux condensate,V formed as hereinafter described, to thermal cracking treatment in a second heating coil, commingling the conversion products from both heating coils and subjecting the mixture to prolonged conversion in a reaction chamber, subjecting a relatively low boiling hydrocarbon oil to thermal reforming treatment in a third heating coil, commingling the conversion products from said thermal reforming treatment and said reaction chamber and fractionating the vaporous fraction therefrom to ments with the light reilux condensate from said4 thermal cracking treatment, and subjecting the mixture to low temperature catalysis.

3. A process for the conversion of hydrocarbon oils to produce gasoline containing a relatively small amount of olefinic hydrocarbons, which.

comprises subjecting a relatively high boiling hydrocarbon oil to thermal cracking treatment in a heating coil, concurrently therewith subjecting heavy reiiux condensate, formed as hereinafter described. to thermal cracking treatment in a second heating coil, conmiingling the conversion products from both heating coils and subjecting the mixture to prolonged conversion in a reaction chamber, subjecting a relatively low boiling hydrocarbon oil to thermal reforming treatment in a third heating coil, commingling th'e conversion products from said thermal reforming treatment and said reaction chamber', separating vaporous conversion products i'rom the non-vaporous liquid residue and recovering the latter, fractionating said vaporousconversion products -to form light and heavy reflux. condensate and to separate vapors 'boiling in the range of gasoline, supplying the heavy reflux condensate to said second heating coil, as previously described, cooling and condensing said vapors and recovering the resulting distillate and gas, heating and vaporizing an oil boiling intermediate to the two iirst mentioned oils in a fourth heating coil and subjecting the resulting vapors to high temperature catalytic cracking treatment, separating vaporous conversion products from the non-vaporous liquid residue formed in said high temperature catalytic cracking treatment, recovering the latter, fractlonating said vaporous conversion products from said high temperature catalytic cracking treatment to form reflux condensate and to separate fractionated vapors boiling in the range of gasoline, cooling and condensing said fractionated vapors and recovering the resulting distillate and gas, commingling the dlstillates from the thermal cracking, thermal reforming, and high temperature catalytic cracking treatments with the light reilux condensate from the thermal cracking treatments, heating the mixture and subjecting th'e heated mixture -to low temperature catalysis, iractionating the conversion products from said low temperature catalysis to separate gasoline boiling range hydrocarbons which are cooled and collected as a product of the process.

4. A process such as defined in claim 3 wherein the reflux condensate from the high temperature catalytic cracking treatment is subjected to further treatment in the same step.

5. A process such as defined in claim 3 wherein the reiiux condensate from the high temperature catalytic cracking treatment is supplied to the thermal cracking ltreatment in commingled state with the heavy reflux condensate.

6. A process such as defined in claim 3 wherein products of the low temperature catalysis, heavier than gasoline, are supplied to the high temperature catalytic cracking treatment.

7. A process such as donned in claim 3 wherein products of the lower temperature catalysis, heavier than gasoline, are supplied tothe thermal cracking treatment in commingled state with the heavy reilux condensate.

8. A process for the conversion of hydrocarbon oils to produce gasoline containing a relatively small amount of oleiinic hydrocarbons, which comprises subjecting a relatively high boiling hydrocarbon oil to thermal cracking treatment in a heatingfcoil, concurrently therewith subjecting heavy'renux condensate, formed as hereinafter described, to thermal cracking treatment in a second heating coil. commlngling the conversion products from both heating coils and subjecting the mixture to prolonged conversion in a reaction chamber, subjecting a relatively low boiling hydrocarbon oil to thermal reforming treatment in a third heating coil, commingling the conversion products from said thermal reforming treatment and said reaction chamber, separating vaporous conversion products from the non-vaporous liquid residue and recovering the latter, fractionating said vaporous conversion products to form light and heavy reflux condensate and to separate vapors boiling in the range of gasoline, supplying the heavy reflux condensate to said second heating coil, as previously described, cooling and condensing said vapors and recovering the resulting distillate and gas, heating and vaporizing an oil boiling intermediate to the two first mentioned oils in a fourth heating coil and subjecting the resulting vapors to high temperature catalytic cracking Itreatment in the presence of silica composited with a compound selected from the group consisting of alumina and zirconia while maintaining the vapors at a cracking temperature, separating vaporous conversion products from the non-vaporous liquid residue formed in said high temperature catalytic cracking treatment, recovering the latter, fractionating said vaporous conversion products from said high temperature catalytic cracking treatment to form reflux condensate and to separate fractionated vapors boiling in the range of gasoline, cooling and condensing said fractionated vapors and recovering the resulting distillate and gas, commingling the distillates from the thermal cracking, thermal reforming, and high temperature catalytic cracking 'treatments with' the light reflux condensate from the thermal cracking treatments, heating the mixture and subjecting the heated mixture to low temperature catalysis in the presence of a cracking catalyst of essentially the same composition as that hereinbefore set forth'while maintaining the temperature of the mixture substantially constant, fractionating the conversion products from said low temperature catalysis to separate gasoline boiling range hydrocarbons which are cooled and collected as a product of the process.

9. A process for the conversion of hydrocarbon oils to produce gasoline containing a relatively small amount of olefinic hydrocarbons, which comprises subjecting a relatively high boiling hydrocarbon oil to a thermal cracking treatment in a heating coil at a temperature of from 800 to 950J F. and at a superatmospheric pressure of from 200 to 600 pounds per square inch, concurrently therewith subjecting heavy reux condensate, formed as hereinafter described, to

thermal cracking Vtreatment in a second heating coil at a temperature of from 900 to 1030 F. and at a superatmospheric pressure of from 400 to 800 pounds per square inch. commingling the conversion products from both heating coils and subjecting the mixture to prolonged conversion in a reaction chamber, subjecting a relatively low boiling hydrocarbon oil to thermal reforming treatment in a third heating coil at a temperature of from 950 to 1050 F. and at a superatmospheric pressure of from 500 to 1200 pounds per square inch, commingling the conversion products from saidthermal reforming treatment and said reaction chamber, separating vaporous conversion products from the non-vaporous liquid residue and recovering the latter, fractionating said vaporous conversion products to form light and heavy reflux condensate and to separate vapors boiling in the range of gasoline, supplying the heavy refiux condensate to said second heating coil, as previously described, cooling and condensing said vapors and recovering the resulting distillate and gas, heating and Vaporizing an oil boiling intermediate to the two first mentioned oils in a fourth heating coil and subjecting the resulting vapors to high temperature catalytic cracking treatment in the presence of silica composited with a compound selected from the group consisting of alumina and .'zirconia at a temperature of from 800 to 1200 F. and at a pressure of from substantially atmospheric to 200 pounds per square inch, separating vaporous conversion products from the non-vaporous liquid residue formed in said high temperature catalytic cracking treatment, recovering the latter, fractionating said vaporous conversion products from said high temperature catalytic cracking treatment to form reflux condensate and to separate fractionated vapors boiling in the range of gasoline, cooling and condensing said fractionated vapors and recovering theresulting distillate and gas, commingling the distillates from the thermal cracking, thermal reforming, and high temperature catalytic cracking treatments with the light reflux condensate from the thermal cracking treatments, heating the mixture and subjecting the heated mixture to low temperature catalysis in the presence of a cracking catalyst of essentially the same composition as hereinbefore set forth at a temperature of from 500 to 900 F. and at a pressure of from substantially atmospheric to 200 pounds per square inch, fractionating the conversion` products from said low temperature catalysis to separate gasoline boiling range hydrocarbons which are cooled and collected as a product of the process.

y EDWIN H. McGREW.