US2206200A - Process for cracking and hydrogenating bituminous oils - Google Patents

Description

E. A. OCON July 2, 1940.

PROCESS FOR CRACKING AND HYDROGENATING BITUMINOUS OILS 2 shwrs-sheet 1 Filed July 17, 19s? Patented July 2, 1940 UNITED STATES PATENT OFFICE PROCESS FOR CRACKING AND HYDRO- Claims.

This invention relates to improvements in a process for treating bituminous oils and their conversion products to obtain enhanced yields of rened anti-knock motor fuels and other valuable 5 commercial products, in particular, by the aid of novel hydrogenation devices and methods which operate efhciently with the use of a low energy input.

More particularly, this invention relates to the recovery of more desirable finished products from partially converted products by a catalytic hydrogenation treatment having low energy input requirements compared with other types of hydrogenation as hitherto practiced, the increase in efciency of the treatment according to this invention being made feasible by a novel principle and apparatus for procuring increased contact catalyst action on reactants. Hitherto in treatments of high boiling carbonaceous materials, especially in the liquid phase, with hydrogen and a hydrogenation catalyst it has been generally considered essential to use pressures of the order of 100 atmospheres and generally above 200 atmospheres and temperatures at which the carbonaceous materials undergo cracking in order to have sufficient hydrogen dissolved in `the carbonaceous material for reaction at the surface of the catalyst. These requirements of high pressure and temperature are expensive, and the high temperature requirement, moreover, becomes detrimental, though hydrogen is more soluble in hydrocarbon oils at higher temperatures, in that the cracking opposes the saturating hydrogenation reaction, in that the cracking causes deposits of tar and coke to adhere to the catalyst surface and thereby decrease the eficiency of the catalyst, and in that the higher temperatures above the equilibrium point of the exothermic saturating reaction favor the reverse reaction of dehydrogenation. It is an objectof this invention to obtain a desired amount of saturating hydrogenation WhileA dispensing with the former high temperature and pressure requirements by bringing the hydrogenating gas into the presence of the material to be hydrogenated at the surface of the catalyst principally by a novel method which permits the gas to diffuse to the catalyst surface separately from the carbonaceous reactants. By this method the hydrogenating gas can be brought in controlled and suitable concentrations on to the catalysts active adsorbent points and into contact with power concentrations .of molecules' of the carbonaceous materials present at the surface.

A further object related to the novel recovery of more suitable products from partially converted heavy oils as described above is in an improved and new use of such products as suitable for improved production of charging stocks for convervsion into anti-knock motor fuels. In accordance with this object, vapor products of the hydrogenation are also beneficially used to strip volatiles from other converted or unconverted heavy oils to obtain desired distillates, the heat energy in the vapor products being thus conserved, and excess hydrogen gas in the vapors being additionally useful in purifying treatments which may be imposed upon the volatiles.

According to another phase of this invention, volatilizedconversion products comprising motor fuel hydrocarbons mixed, with hydrogen are subjected to an improved hydrogenation refining for eliminating undesirable components, such as gum forming and non-hydrocarbons, without substantial impairment of the anti-knock characteristics of the motor fuel. This hydrogenation refining, more particularly, is carried out with hydrogenation catalysts of controlled activity and with controlled conditions. Hitherto in the art, highly active hydrogenation catalysts which are generally very active in promoting a hydrogenating reaction but are at the same time very sensitive to poisoning, have been suggested foruse in re- `ning gasoline hydrocarbons to saturate gum 'forming constituents such as diolens and to split out sulphur, oxygen, and nitrogen atoms from hetero-organic compounds. It has been found that in the early part of the use of `these sensitive catalysts the saturating reaction is so high that anti-knock components such as aromatics become transformed to less anti-knock components, that the activity of the catalysts rapidly decreases be-l cause of vtheir highsusceptibility to poisoning, and that as a consequence the reaction is not uniform. It is an object of this phase of the invention in particular to select catalysts prepared to have a desired and more uniform degree of activity.

A further object of this invention is to make use of novel steps which permit partially converted vapors from a conversion zone to be subjected to treatments for elimination of tarry substances and in a series of purifying and stripping zones to aid in producing purified cracking stock distillates. In particular, this embodiment of the invention involves a treatment of converted vapors at a lowered temperature toremove gum forming and tarry substances followed by a subsequent rise in the temperature of the thus treated vapors so that they can be further puried at a higher temperature so as not to be detrivvmental to the anti-knock value of the motor fuel constituents. p

One of the main problems in the production of gasoline by. cracking heavy hydrocarbon oil mixtures is that of increasing the yield of desired low boiling fractions with increased economies lin heat and materials. The limit of yield in most commercial processes is reached when the residual products have been exsiccated to produce coke, as, by what is calledashing, which is a material requiring special expensive handling and ofl relatively low value. It has been appreciated for sometime by those familiar with the cracking process that it is difficult to recover more valuable fuels from the residual oils due to the tendency of the residual oils to form coke. The present invention is partly concerned with measures for eliminating prior difficulties in recovering more valuable liquid fuels from the undesirable byproducts of the cracking process, the particular features of the process being hereinafter fully disclosed. I

Another problem in the production of gasoline by cracking is that of eliminating impurities from the produced motor fuels most economically and without deteriorating the anti-knock values. In processes previously proposed, diiilculties have been encountered in removing the ,deleterious constituents without impairing the emciency of the process. The present invention is also concerned with measures for removing the detrimental constituents from the desirable gasoline products, the particular features of the process being hereinafter disclosed.

The apparatus and process will be described with reference to the accompanying drawings, in which:

Fig. l diagrammatically illustrates the conventional apparatus involved; p

Fig. 2 shows schematically an enlarged sectional view of the construction of the conventional hydrogenating zone in which one reactant is made to reach the catalyst surface independently of another reactant;

Fig. 3 illustrates a furnace showing conventional disposition of coils. A

In Fig. 1 is illustrated that a bituminous oil charging stock, preferably preheated to below cracking temperatures under pressure, is passed into a lower section of a primary tower 4 by means of valved line l and jet 3. A desulphur- 'izing absorbent or adsorbent, such as lime, ad-

sorbent earth, etc., may be injected into the lower section with the charging stock, being added as by valved line 2. The flashing of the charging stock is beneficially aided by a blast of hot vapors and gases from the spray inlet 5, located below .iet 3 to strip light fractions from the unvaporized liquid charging stock to increase the amount of vapor. Vapors and gases pass upwardly in the tower 4 to be fractionally condensed through the use of conventional dephlegmating means to form one or more distillates for cracking and reforming, such as distillates which may be withdrawn by valved lines 9 and I0. The vapors and gases may be made to pass to the dephlegmating section of tower 4 (which may be a plurality of such towers) through a contact mass 6, made up of adsorbent material such as lumps of activated clay, unglazed porcelain rings, china clay, bauxite, silica gel,` metal rings, etc., or such as massive contact materials coated with moderately sensitive hydrogenating catalysts which will be hereinafter described. It is to be understood that said vapors and gases from tower aaoaaoo 4 may be subjected to the action of the contact mass in a. separate zone and then returned to tower 4 to be fractionally condensed. Unvaporized materials drop to the bottom of tower 4, and are permitted to stratify into a bottom layer of heaviest oils and chemical sludge, and an upper layer of residual oil, which are withdrawn oif by valvedl lines 1 and 8, respectively.

An intermediate fractional condensate of a gas oil type which lmaybe mixed with conversion recycle stockv introduced into the tower 4 by line i2 as a refluxing medium, is passed by valved line 9 to be cracked in coil I5 at a temperature of about 900 F., preferably in the vapor phase, under suitable pressure in the range of about 30 to 350 lbs. per sq. inch, with a reaction period of about 1 to 20 minutes, and the temperaturev being varied in accordance with these factors to obtain a high yield of gasoline products. The hot converted products are passed from coil i to separating tower 28, being lowered in temperature, if desired, tov some extent as in heat exchanger I6.

Residual oils, substantially separated from tarry materials and chemical sludge, are withdrawn by line 8 and 8 from tower 4 and are led preferably through a heating coil I4 to be heated to a viscosity breaking temperature or incipient cracking temperature of about 700 to 800 \F., thence passed into an intermediate section of separator 28, as for example, into a pool of liquids partly retained on pan 32, which may have perforations through which the tarry residual drops to the stripping zone. It has been found helpful to have the hot oils injected into the pool abover pan 32 to cause agitation of the liquid to secure further vaporization with an overflow of unvaporized oil from the pool downwardly and countercurrent to a stream of hot vapors, such as enter from a spray inlet 33 for stripping aotion. Hot cracked vapors from coil i5 may be used. This manipulation aids in the stripping of volatiles from the liquids. Spray inlet 34 near the base of tower 28 may be provided for the injection of additional hot gases and vapors. Above pan 32 can be provided baille means for knocking down tarry particles entrained in the vapors, and an inlet 3i for a refiuxing medium, such as recycle stock from'a fractionator 22.

An indirect heat exchange coil 30, inwhich a portion of recycle stock from fractionator 22 can absorb heat from vapors passed over the coil;

and a contact mass bed 29, similar in function to the contact mass 6 in tower 4 may be situated near the top of tower 28. In a manner similar to that described with respect to tower 4, lighter residual oil freed -from tarry substances and chemical sludge can be withdrawn from the upper part of a pool of residuals which collects at the base of tower 28 by means of valved line 36, and the heavier residuals together with any sludge can be withdrawn from the lowest part of tower 28 by means of drain pipe 3l. Valved vapor draw olf lines 35 and 20 can be connected to the upper part of tower 28.

Vapors released from. liquids commingled with vapors and gases introduced into separator 28 are preferably subjected to a cooling and purification in the upper part of the separator by means already described. The cooling action, as by means of cooling coil 30 or liquids and desulphurizing agent introduced through inlet 3|, is preferably controlled to lower the temperature of the vapors to about 700 F., or less. The contact mass bed 29 is preferably made up of mateforming zone I3 joining the overhead vapors l from the separator 28 at the junction of line I1 with line 20. Other `well known means can be used to raise the temperature of the vapors from separator 28 passed to the selective hydrogenation zone, such as an electric heater or heat exchanger in line (not shown) or a heating jacket surrounding vessel 2I. It is preferable to maintain the temperature in the selective hydrogenation suiliciently elevated to avoid the hydrogenation of the anti-knock constituents such as the aromatics and oleflnes. In general the selective hydrogenation temperature should be in the range of 700 to 800 F., approximately.

Lighter residual oils separated from tarry substances and chemical sludge are passed by line 36 to a catalytic hydrogenation zone 45 to contact with hydrogenating gas at catalytic surfaces as will be more specifically explained in connection with Fig. 2. Hydrogen or hydrogenating gas from well known sources, including hydrogen from cracking and reforming, removed from. the xed gases, is passed into zone 45 by valved line 40. Residual oils from line 36, which may be mixed with hydrogen or hydrogenating gas from valved line 39, and diluted with hot vapors led from tower 28 by line 35 or line 20 and are passed into zone 45 by line 44. In zone 45 the oils are subjected to asaturating hydrogenation under conditions such that no substantial cracking takes place and mainly for the purpose of treating the cracked residual components so that they can be more readily subjected to vaporization without forming undesirable amounts of coke. The hydrogenation is intended to mainly transform the residual oils into distillable products which are more amenable to further heat treatment. The hydrogenation products whle'hot are sprayed or flashed into separator 83, in which vaporization is further aided by hot vapors and gases, such as may be led in by spray inlet 46 from line 43, line 35, line 66 and line 38. Unvaporized oil in separator 63 is withdrawn by drain pipe 49, while vapors and gases are released through line 50, the vapors and gases being filtered first through a contact mass bed 48, which may be similar in nature to contact mass 8 in tower 4. Baiiles 41 in separator 63 are meant to aid in distributing liquids and vapors for more intimate contact between the liquids and vapors.

Residual oils withdrawn from separator 63 and residual oils withdrawn from tower 4 may be further treated as by hydrogenation or chemical treatment to recover improved fuel oil or lubricating oil stocks.

Vapors and gases withdrawn from separator 83 by line 50' are useful for stripping and for forming additional distillate either in tower 28 or in tower 4, being passed to either or both by lines 5I and 52, and intermediately through the heat exchanger I6 to either line if desired. In tower 28 these gases and vapors are injected through spray device 34; in tower 4 by spray de-l genated vapors from tower 4 composed mainly of gasoline constituents, which may be partly straight run, by line Il through a filtering contact mass 539:, of materials selected from a group comprising diatomaceous earth, kieselguhr, silica gel, infusorial earth, bentonite, fullers earth, clay, etc., mixed with phosphoric acid, or of siliceous materials treated with a mixture of oxygen compounds of phosphorus such. as a mixture of phosphoric acid, pyro phosphoric acid, phosphorus acid, and meta phosphoric acid, or through hydrouorized siliceous materials, to a cooler 54 and then to a receiver and fixed gas separator 55, whence a finished product is discharged by valved line 56, the iixed gases being passed or pumped to a bubble tower 51 for removal of additional hydrocarbons. From the bubble tower the 'remaining gases containing liydrogen and methane etc., mainly, are led by line :6I to a well known ,type of means .62 for obtaining a gas largely composed of hydrogen,.such as a means for reacting the fixed hydrocarbon gases with an oxidizing gas, such as oxygen, steam, or carbon monoxide, From 62 the hydrogenous gas may be led to distributing lines 40, 39, and 66.

From upper dephlegmating trays in towel 4, reforming stock such as heavy naphtha, or kerosehe components and naphtha components may be led by valved line I0 to a reforming coil I3 to be raised to a high temperature in a space of less than one minute, to a temperature in the rang of about 800 to 900 F., to be contacted with a dehydrogenating or dealkylizing and isomerizing catalyst in a still shorter or corresponding period of time.

From reforming coil-l3 the products may be sent by line I1 to join the vapors and gases from tower 28 in line 20, or be by-passed by line I8 through heat exchanger I9.

Vapors and gases from line 28 are preferably sent through a hydrogenation purifying zone 2|, wherein, at a temperature in the range of about 700 to about 800 F., they are treated in the presence of hydrogen to a mild hydrogenation catalyzing action controlled to saturate undesirable constituents such as diolefins and to split ori foreign atoms such as sulphur. The products from line I8 and from zone 2I may .be passed to the fractionator 22 to fractionate out liquids higher Aboiling than gasoline hydrocarbons. A liquid fraction of the nature of gas oil and kerosene components may be collected at the bottom of the tower, and such liquids may be used for recycling to towers 28 and 4 by lines 25, 20, inlet 3I, coil 30, and line I2. The overhead of desired motor fuel components may be removed to line 53. A liquid condensate of heavy naphtha type collected in tray 23 may be recycled by line 24 to coil I3. If desired, said naphtha. condensate can be passed through heat exchanger I9.

If desired, however, the fractionator 22 may be eliminated, the` vapors from lines I1, 20, and I8 being passed back by way of line 35 and other` connecting lines, shown, to tower 4. This elimination of a second fractionating tower is made possible with this invention and procures a new economical advantage for small refineries.

Desulphurizing adsorbent or absorbent material, such as is added to tower 4 by line 2, may be injected with charge oilvby line 21 to tower 28.

Liquids composed mainly of normally gaseous hydrocarbons may` be Awithdrawn from the bubble tower 51 to be treated by a light polymerization as by alumina, floridin earth, or metal halides at low temperatures to produce dimers and trimers, which in turn may be sent to the hydrogenating zone 2| controlled to produce a partial. hydrogenation of the unsaturated gasoline constituents to mainly saturate any dioleflns and partially saturate mono-olens. In accordance with manipulation the antiknock value of the gasoline can be further enhanced with further economies. An improved control of the hydrogenation can be made by use of the hydrogenation apparatus shown in Fig. 2.

The catalysts to beused with the type of catalysis disclosed in accordance with this invention for saturating hydrocarbons can be less insensitive to poison than catalysts hitherto proposed. Metals and their compounds which are diiicult to sulphide but which are highly active in hydrogenation at the temperatures of reaction, such as, vanadium, chromium, nickel, cobalt, zinc, tin, molybdenum, titanium, magnesium, also the oxides of the alkaline earth metals, of copper, aluminum, magnesium, etc.

In using catalysts for removing sulphur compounds and partially or selectively saturating unsaturated hydrocarbons which are undesirable in the gasoline product as in catalyst bed 6 or reiining zone 2l, it is preferable to use sintered `metals or compounds. i

In Fig. 2.is shown a'schematic cross sectional view of the hydrogenation zone 45 to illustrate more clearly how the hydrogenous gas or hydrogen is led into the inner part of the catalyst or catalyst support by line 40. The support4 6@ may be constructed of any strong porous material, such as metals or non-metals which naturally or by processing are permeable to the hydrogenating gas to be 'led into the interior St of the hollow supports and made to pass through to the surface of the supports. Metals in the eighth group of the periodic system are known to have the property of permeability to hydrogen by solution of the gas in the metal tov some extent and by capillary diiusion of the gas through the metal, but these metals can be made still more permeable by forming an alloy of the metals to be used as the catalyst or support with another substance which'isY later leached out to leave catalytic or supporting metal in a skeleton form' for increased diffusion of the gas. Such an alloy can be made of metals in the iron group' with a substance more corrodible by specific acids or alkalies, such as aluminum or silicon. Similarly alloys of other metals can be made, such as metals in the sixth group to produce catalyst or supports which are permeable to the hydrogenating gas. l Hollow or tubular clay supported catalysts permeable to hydrogen can be made by compressing a powdered hydrogenation catalyst on the outer surface of the clay, hardening the clay, as by baking, and then leaching out silicon constituents of the clay by treating with hydroiluoric acid.

Another method of forming the gas permeable support of catalyst to be used in accordance with this invention is that of compressing an oxide of the metal into the desired form, then subjecting the formed material to reduction at controlled low fusion temperatures.

In using the thus formed supports in the catalysis of reactions in which the reactants contain poisoningimpurities, such as oxygen or sulphur containing carbonaceous material, the permeable support can be made to have a contact surface immune to poisoning. For example, an iron support can be given a light coating of tin, or be given a contact surface of iron oxide by a light oxidation of the surface, which is readily formed upon exposure to air. In forming an oxide layer of more oxidation resistant metals, more intense reactants, such as pure oxygen, hot steam, or oxiding acids can be used. Similarly, other surface coatings of sulphides, halides, nitrides, arsenides, or other compounds can be formed. The highly porous and activated supports formed in the manner described are also in a condition to readily adsorb upon their surfaces colloidal catalysts from a colloidal sol. Promoters, such as, metalloid compounds, and heteropolymeric compounds, and other stable crystalline compounds may be used.

A number of advantages accrue from the use of catalysts of the type described. Besides permitting more ready contact between the reactants at the surface with low energy input, it provides for a more ready desorption of the products of the reaction, a removal of heat of reaction, truer control of the reaction, and a more highly active catalyst. The hydrogenating gas in positively being diffused to the active surface of the catalyst can absorb heat from the surface and the heat conducted by the support from the surface, since the gas can be led into the interior of the support at lower temperatures than are maintained at the surface by the other reactants, such as the carbonaceous liquids, and by the heat of reaction, the diffusion of the gas from a lower temperature and even a lower pressure zone to a higher temperature zone being possible in accordance with the principle of thermal transpiration. Since the passage of the hydrogenating 'gas to the surface can 'be positively controlled, the gas can be independently controlled to remove inhibiting rreaction products and adsorbed poisons, as for example by a pulsating iiow of the gas to the surface or increased flow of the gas at intervals to the surface so that more highly concentrated gas reacts with the inhibiting material at intervals.

Although the use of the catalyst which provides for a separate approach for the different reactants to the catalytic surface is exemplified here mainly in its use for hydrogenating carbonaceous materials such as unsaturated and polymerized products of cracking, it is believed to be valuable in other reactions, such as in the hydrogenation of carbon monoxide, in which the lighter or more diffusive reactant can be made to diffuse through the porous catalyst or support to contact in the presence of the less diffusive reactant at the active surface. It is also contemplated that other physical means can be used to increase the diffusion of the reactants to the active catalyst surface and to improve the possibilities of proper orientation and activation at the surface, such as ionization or electrical activation by electro-magnetic Waves of high frequency or electrical discharges, electromagnetic poi-irization of the reactant molecules, vibratory motion induced by supersonic Waves, and wetting agents to promote contact of the hydrocarbons with the solid catalysts.

In hydrogenating cracked residual liquids, semi-liquids and normally solid material as practiced hitherto it has been found essential to supply hydrogen under high superatmospheric pressure and high temperatures directly to the carbonaceous materials in order to have sufficient hydrogen in solution to be present at the catalyst surface. In accordance with the present invention subatmospheric pressures or low pressures less than 1,000 cu. ft, of hydrogenati Ans can be used as well, also hydrogenating temperatures below 300 C., can be used as well as temperatures above this which have hitherto been indicated. Along with this conservation in energy. the conservation in hydrogen is made possible since the hydrogen is made to be present Where it is needed, at the active sunlace; hence, g gas need be employed per barrel of oil to be hydrogenated. Conditions are preferably regulated in catalytic chamber to make the residual oil more'saturated, with reduced gravity and viscosity so that it is more readily distilled without coking in chamber 83. In general, low pressures of the order of subatmospheric, atmospheric, slightly elevated pressures, such as several atmospheres are advantageous along with moderate temperatures of 600 to 800 F., approximately, the oil being flowed at a rate so that it is subject to very little crackingat these temperatures. At 800 F., the oil is treated for a period of less than about 20 minutes; at higher temperatures the period is shortened. The hydrogenating gas is supplied to the interior 64 of the catalyst or support at a rate sufficient to keep the catalytic surface at least partly saturated with a monmolecular layer of the gas. Some hydrogenating gas may advantageously be supplied directly to the oil entering the catalytic chamber tr ensure distribution of the gas. In general, at least about the same mass of hydrogen as the mass of the oil fed to the catalytic zone is required. Temperature and pressure ranges, proportions of materials, and time cannot be exactly defined since these are dependent upon the oil treated, the catalyst used, and upon one another. In the selective hydrogenat'ion reaction such as carried out in vessel 2l much less hydrogen is used.

Steam or other hydrogenous gas may be supplied to the heating coils I3, I4, and I5, and separator 63 by means of lines 59, 49m, 48m, and 58 respectively, to aid in vaporization and in reducing viscosity of the oils being heated in these zones also to aid in the catalysis.

Steam may also be passed in highly heated state into the heating jacket surrounding vessel 2| by valved line 65 to raise the temperature of the vapors or to avoid loss of heat in said vessel 2|, the steam being passed out throughvalved line 61.

It is to be understood that contact mass beds y 4B and 29 in zones 63 and 28 respectively, may be disposed in zones distinct from said zones 63 and 28, if desired.

Raw oil charging stocks of varied character may be used. A crude petroleum is suitable, but heavy distiliates of a topped crude may be used. Analogous bituminous or pyrobituminous materials, such as shale oils, lliquefaction products of coal, powdered coal suspended in a carbonaceous liquid medium, etc., may-also be used, especially as such materials respond readily to the efficient action of the type of hydrogenation catalysis described.

Instruments such as thermowells, temperature controllers and recorders, pumps, compressurors, gauges, etc., are not indicated or mentioned, but it is to be understood that they will be used as required, as is well known in the art.

Although the herebefore described method is` preferred, the system of operation may vary considerably as there are characteristics in structure and apparatus which make my invention one of broad application, and it is to be undertillate, heating such distillate under cracking ing resultant vapors from the cracked products, filtering separated vapors through a contact mass for eliminating deleterious gum and tar forming materials, passing thus filtered vapors maintained continuously in vapor phase into contact with said bituminous materials undergoing distillation in said distillationV zone, and Withdrawing as overhead products from said distillaconditions of temperature and pressure to form lower boiling products of naphtha range, separattion zone a motor fuel vapor product separated A from cracking stock distillate by fractionation.

2. A process for treating bituminous oils to produce gasoline fuel which 'comprises distilling initial uncracked bituminous oils higher boiling than gasoline motor fuel in a distillation zone to produce a cracking stock distillate and heavier residual oil, heating such distillate in a cracking zone under cracking conditions to form gasoline fuel vapor products and higher boiling liquid products, passing such liquid products produced in the cracking zone to a hydrogenating zone wherein they are subjected to a saturating hydrogenation, passing products of the hydrogenation zone to a vapor stripping zone, passing hot hydrogenated vapors maintained continuously in the vapor phase from the stripping zone to the distillation zone to aid in the distillation of the initial bituminous oils by directly contacting with said initial bituminous oils undergoing vaporization in the distillation zone and fractionating vapors in said distillation zone to obtain a cracking stock distillate and a motor fuel product.

3. A process for producing from high boiling bituminous material a hydrogenated gasoline and other low boiling point products which comprises distilling in a distillation and fractionation zone an initial uncracked bituminous material with the aid of hot hydrogenated vapor products passed into contact with said initial material in said zone, fractionating and condensing in said distillation and fractionation zone at least a reforming stock distillate of heavy naphtha range, an intermediate cracking stock distillate higher boiling than naphtha and a residual cracking stock from the distillation, cracking said residual stock in a heating zone at a pressure for a period of time sufficient to produce therefrom Avapor products of naphtha range, cracking under conditions of temperature and pressure in a heating zone for a period of time sufcient to produce naphtha range products the intermediate stock distillate higher boiling than naphtha fractionated from the distillation, reforming in a heating zone under suitable conditions of temperature and pressure the reforming stock distillate of heavy naphtha range, mixing the resultant cracked and reformed products, separating in a separation zone mixed cracked and reformed vapor from liquid residual products, fractionating said mixed vapors to condense out a fraction higher boiling than naphtha, hydrogenating in a hydrogenation zone under suitable conditions of temperature and higher pressure than the pressure maintained in the distillation and fractionation zone a portion of the heavy naphtha range fractions jointly with at least a portion of the condensed fraction higher boiling than naphtha. separating mixed vapor products evolved from the hydrogenation from liquids, and using said hydrogenated vapor products ytoaid in the distillation of the initial .uncracked bituminous material to obtain in the distillation and fractionation zone overhead nydrogenated products of gasoline range and products of higher boiling point.

4. A process such as claimed in claim 3, in which the products of the hydrogenation are further vaporized with the aid of hot hydrogenous vapors and gases to increase-the amount of hydrogehated vapor products which aid in the y distillation of the initial uncracked bituminous material.

5. A process as claimed in claim 3, in which the hydrogenated vapor products are passed through a contact mass for elimination of deleterious gum and tar forming substances and said contact mass containing catalysts of the hydrogenation type.

ERNEST A. OCON.

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