US3203889A - Catalytic hydrocracking process with the preliminary hydrogenation of the aromatic containing feed oil - Google Patents

Description

United States Patent 0 3,203,889 CATALYTEC HYDROCRACKING PROCESS WITH THE PRELHVHNARY HYDROGENATION OF THE AROMATIC QUNTAI'NING FEED 01L Ernest L. Pollitzer and Vladimir Haensel, Hinsdalc, ilk, assignors to Universal Oil Products Company, Des Piaines, 111., a corporation of Delaware Filed Nov. 1, 1962, Ser. No. 234,703 14 Claims. (U. 2tl8'57) The present invention encompasses a process for converting an aromatic-containing hydrocarbonaceous charge stock into lower-boiling hydrocarbon products by a method which involves the utilization of catalytic cracking in the presence or" hydrogen. More specifically, the present invention is directed toward a combination process for the production of hydrocarbons boiling within the normal gasoline boiling range from hydrocarbonaceous material boiling at temperatures exceeding the normal gasoline boiling range, which hydrocarbonaceous material is contaminated by the presence of exceedingly large quantities of nitrogenous and sufurous compounds, and which contains monoand polynuclear aromatic hydocarbons. The process of present invention is particularly adaptable for the conversion of hydrocarbonaceous material boiling at temperatures exceeding the normal middle-distillate boiling range, and offers flexibility with respect to the quality of the lower-boiling hydrocarbon product where it may be desired to maximize the production of gasoline boiling range hydrocarbons, or middle-distillate boiling range hydrocarbons, or to produce an economically-dictated balance therebetween.

Hydrocracking, sometimes referred to as destructive hydrogenation, involves the cracking of hydrocarbona ceous material in the presence of hydrogen and a suitable catalytic composite, and eifects a change in the molecular structure of such hydrocarbonaceous material. Hydrocracking may be designated as cracking under hydrogenation conditions such that the lower-boiling products of the various conversion reactions are substantially more saturated than when cracking in the absence of hydrogen, as in a thermal cracking process. Hydrocracking processes are most commonly employed for the conversion of a wide variety of coals, tars, petroleum crude oils, heavy residual oils, heavy vacuum gas oils, etc., having as the object the production of lower-boiling, saturated products; to a certain extent, intermediates which are suitable for utilization as domestic fuels, and heavier gas-oil fractions which find utilization as suitable lubricants, are also produced. Although many of the present-day cracking processes may be, and are, conducted on a strictly thermal basis, the preferred refining technique involves the utilization of a catalytic composite possessing a high degree of selective hydrocracking activity, in an atmosphere of hydrogen. The use of such a catalytic composite affords the desired degree of control by which the cracking reactions being etfected are made more selective from the standpoint of producing an increased yield of normally liquid hydrocarbon product having improved chemical and physical characteristics. Furthermore, controlled or selective hydrocracking assumes greater significance in order to achieve acceptable stability and effective catalytic action over a prolonged period of time.

Selective hydrocracking is of particular importance when processing hydrocarbons and mixtures of hydrocarbons having normal boiling points at temperatures above the normal gasoline and middle-distillate boiling ranges; that is, hydrocarbons and various mixtures of hydrocarbons, as well as hydrocarbon fractions and distillates, having a boiling range indicating an initial boiling point of at least about 650 F. and an end boiling point as high as about lOOO E, or more. In the present specification, the term gasoline boiling range is intended to connote a temperature range having an upper limit of about 400 F. to about 425 F.; the term middledistillate range, is herein designated to include temperatures above the gasoline boiling range, but not substantially in excess of about 650 F.; middle-distillate hydrocarbons include, therefore, kerosenes, light gas oils, fuel oils, etc. Selective or controlled hydrocracking of hydrocarbonaceous material having a boiling range greater than the middle-distillate boiling range, results in significantly greater yields of hydrocarbons boiling within the gasoline and middle-distillate boiling ranges. Selectivity is further required in order to avoid the usually experienced excessive decomposition of the normally liquid gasoline and middle-distillate boiling range dydrocarbon substantially or completely into normally gaseous hydrocarbons, the latter generally considered to be waste products. As a result of the excessive production of normally gaseous hydrocarbons, inherent in uncontrolled, non selective hydrocracking, the volumetric yield of valuable boiling range hydrocarbons is rapidly decreased to the extent that the process is not economically feasible. In illustration, it might be said that selective hydrocracking involves the splitting of a higher-boiling hydrocarbon molecule into two molecules, both of which are normally liquid hydrocarbons boiling within the gasoline and/or middle-distillate boiling ranges. Thus, selective hydrocracking minimizes the removal of methyl, ethyl and propyl groups, which, in the presence of hydrogen, are converted to methane, ethane and propane, the'latter herein referred to as light parafiinic hydrocarbons. Through the judicious choice of operating conditions and catalytic composition, depending primarily upon the physical and chemical characteristics of the charging stock, the production of the aforesaid radicals is controlled in order to produce acceptable yields of normally liquid hydrocarbons. Conversely, non-selective cracking, as experienced in present-day catalytic cracking units, when permitted to exist unabated, will result in the decomposition of normally liquid hydrocarbons into normally gaseous hydrocarbons; for example, the continuous demethylation of normal heptane produces seven methyl groups which are converted to seven molecules of methane. Another disadvantage of non-selective hydrocracking, particularly in regard to catalytic processes is the resulting rapid formation of increased quantitles of coke and other heavy hydrocarbonaceous material which becomes deposited upon the catalyst and decrease, or destroys, the stability and the activity thereof to catalyze the necessary reactions in the desired, controlled manner. The efliciency of the process decreases, and a shorter acceptable processing cycle results, accompained by the inherent necessity of more frequent regeneration of the catalytic composite employed, or

total replacement thereof with fresh catalyst. Furthermore, the deactivation of the catalyst appears to inhibit the hydrogenation activity thereof to the extent that a significant proportion of the gasoline and middledistillate boiling range products consist of unsaturated parafiins, whereby the product are not suitable for immediate utilization or for subsequent direct processing by catalytic reforming. Through the utilization of the selective hydrocracking process and catalytic composites of the present invention, a hydrocarbon charge stock,

consisting entirely of hydrocarbons boiling above the middle-distillate boiling range, is converted into hydrocarbons boiling within the gasoline and middle-distillate boiling ranges, and a significant increase in catalyst stability is experienced.

Investigations into the problems attendant acceptable hydrocracking processes have further indicated that the presence of nitrogen-containing compounds within the hydrocracking charge stock, regardless of the precise boiling range thereof, results in the relatively rapid deactivation of the catalytically active metallic component, as well as the solid carrier material which serves as the acid-acting hydrocracking component, and that the adverse effects of nitrogenous compounds are singificantly more deleterious than those exhibited by sulfurous compounds. The rapid deactivation of the catalyst appears to result primarily from the reaction of nitrogenous compounds with the various catalytic components, the extent of such deactivation increasing as the process continues and as the charge stock further contaminates the catalyst through contact therewith. This deactivation is not a simple reversible phenomenon which may be easily rectified, for example, by the relatively simple expediency of heating the catalyst in a suitable atmosphere for the purpose of decomposing the nitrogen-containing complexes, or overcoming the adverse effect exhibited by the sulfurous compounds. As a result, certain hydrorefining processing techniques have been suggested as a means of pretreating the charge stock for the purpose of eliminating land/or decreasing the concentration of the nitrogenous and sulfurous compounds. As hereinafter set forth in greater detail, such hydrorefining techniques, we have found, fail to pretreat, or clean-up, the charge stock to the extent required for an extended period of acceptable, stable catalytic activity during the hydrocracking operation. We have found that, in addition to nitrogenous compounds, the hydrocracking process is adversely afiected by the inclusion of high boiling monoand polynuclear aromatics within the pretreated hydrocracking charge stock.

A primary object of the present invention is to provide a catalytic hydrocracking process which results in substantially greater yields of hydrocarbons boiling within the middle-distillate boiling range, while processing petroleum hydrocarbon charge stocks boiling in excess of the middle-distillate boiling range. A related object is to provide a process utilizing a particular catalytic composite and reaction chamber arrangement which permits the utilization of a hydrocarbon charge stock not only containing relatively excessive quantities of residual nitrogenous and sulfurous compounds, but which also contains detrimental quantities of monoand polynuclear aromatics otherwise having the tendency to cause the rapid deactivation of the catalytic composite. An advantage of the process of the present invention is the inherent flexibility with respect to the quality and quantity of the final product produced; that is, the production of substantially large yields of gasoline boiling range hydrocarbons while simultaneously maximizing (or minimizing where desired) the quantity of middle-distillate hydrocarbons. Furthermore, the process of the present invention makes possible the simultaneous production of gasoline boiling range hydrocarbons, kerosene fractions suitable as jet fuel blending components, and middledistillate hydrocarbon fractions, all of which are substantially completely free from sulfurous and nitrogenous compounds.

In a broad embodiment, therefore, the present invention encompasses a process for converting hydrocarbonaceous material containing aromatic compounds into lower-boiling hydrocarbon products, which process comprises reacting said hydrocarbonaceous material with hydrogen in contact with a non-acidic hydrogenation catalyst and at hydrogenation conditions selected to hydrogenate said aromatic compounds; thereafter reacting the substantially aromatic-free hydrocarbonaceous material with hydrogen at hydrocracking conditions and in contact with an acidic hydrocracking catalyst.

In one particular modification, the present invention relates to a process for converting hydrocarbonaceous material containing aromatic compounds into lowerboiling hydrocarbon products, which process com-prises reacting said hydrocarbonaceou material, at hydrogenation conditions, and in admixture with hydrogen, in a reaction chamber containing an upper zone of a substantially non-acidic hydrogenation catalyst and a separated lower zon of an acidic hyd-rocracking catalyst; aid hydrogenation conditions including a maximum catalyst temperature less than about 650 F. and selected to hydrogenate aromatic compounds; reacting the substantially aromaticfree hydrocarbonaceous efiluent from said upper zone, at hydrocracking conditions and in contact with said acidic hydrocracking catalyst; separating the resulting reaction chamber efiiuent to provide a hydrocarbon fraction having an initial boiling point of at least about 400 F. and recycling at least a portion of said fraction to combine with said hydrocarbonaceous material.

In another broad embodiment of the present invention, there is described a process for converting hydrocarbon-aceous material containing aromatic compounds into the lower-boiling hydrocarbon products, which process comprises passing said hydrocarbonaceous material, at hydrogenation conditions and in admixture with hydrogen, into a reaction chamber containing an upper zone of a substantially non-acidic, non-siliceous hydrogenation catalyst and a separated lower zone of an acidic hydrocracking catalyst; said hydrogenation conditions including a temperature of at least about 300 F., selected to provide a maximum catalyst temperature less than about 650 F. and to hydrogenate aromatic compounds; reacting the substantially aromatic-free hydrocarbonaceous efiluent from said upper zone at hydrocracking conditions including a temperature within the range of from about 400 F. to about 950 F. and in contact with said acidic hydrocracking catalyst; separating the resulting reaction chamber etfiuent to provide a hydrocarbon fraction having an initial boiling point of at least about 400 F., and passing at least a portion of said hydrocarbon fraction into said reaction chamber at a point intermediate said upper and lower zones.

A more specific embodiment of the present invention afifords a process for converting hydrocarbonaceous material containing more than about 10 ppm. of nitrogen and aromatic compounds which comprises the steps of: (a) reacting said hydrocarbonaceous material with hydrogen, at hydrorefining conditions selected to convert nitrogenous compounds into ammonia and in con-tact with a nitrogen-insensitive catalyst; (b) separating the resulting reaction product effiuent to provide a substantially notrogen-free liquid hydrocarbon and an ammonia-containing gaseous phase; (0) passing said nitrogen-free liquid hydrocarbon, at hydrogenation conditions and in admixture with hydrogen, into a reaction chamber containing an upper zone of a substantially non-acidic hydrogenation catalyst and a separated lower zone of an acidic hydrocracking catalyst, said hydrogenation conditions including a temperature of at least about 300 F., selected to provide a maximum catalyst temperature less than about 650 F. and to hydrogenate aromatic compounds; (d) reacting the substantially aromatic-free product from said upper zone at hydrocracking conditions and in contact with said hydrocracking catalyst; (e) separating the resulting reaction chamber efiluent to provide a hydrocarbon fraction having an initial boiling point of at least about 400 F. and recycling at least a portion of said fraction to combine with the aforesaid substantially nitrogenfree liquid hydrocarbon.

A more specific embodiment of the present invention involves a process for converting hydrocarbonaceous material containing aromatic compounds and more than about 10 ppm. of nitrogen, which process comprises the steps of: (a) reacting said hydrocarbonaceous material with hydrogen, at hydrorefining conditions including a temperature within the range of from about 600 F. to about 850 F. and selected to convert nitrogenous compounds into ammonia, and in contact with a nitrogeninsensitive catalyst comprising molybdenum and from about 1.0% to about 6.0% by weight of an iron-group metallic component; (b) separating the resulting product efiluent to provide a substantially nitrogen-free liquid hydrocarbon and an ammonia-containing gaseous phase; (c) passing said nitrogen-free liquid hydrocarbon, at hydrogenation conditions and in admixture with hydrogen, into a reaction chamber having an upper zone of a substantially non-acidic, non-siliceous hydrogenation catalyst containing a platinum-group metallic component and at least one metallic component selected from the group consisting of alkali metals and alkaline-earth metals, and a separated lower zone of an acidic hydrocracking catalyst comprising at least one metallic component selected from the group consisting of the metals of Group VI-A and VIII of the Periodic Table, said hydrogenation conditions including a temperature of at least about 300 F., selected to provide a maximum catalyst temperature less than about 650 F. and to hydrogenate aromatic compounds; ((1) reacting the substantially aromatic-free hydrocarbonaceous effluent from said upper zone at hydrocracking conditions including a temperature within the range of about 400 F. to :about 950 F. and in contact with said acidic hydrocracking catalyst; (e) separating the resulting reaction chamber effluent to provide a first hydrocarbon fraction boiling within the gasoline boiling range and having an end boiling point of from about 400 F. to 425 F., a second fraction having an end boiling point of about 650 F. and a third fraction having an initial boiling point of at least about 650 F., and passing at least a portion of said third fraction into said reaction chamber at a point intermediate said upper and lower zones.

The applicability of the present invention for the production of lower-boiling hydrocarbon products from heavier hydrocarbonaceous material, accompanied by in creased catalyst stability, may be more clearly understood by defining several of the terms and phrases employed Within the specification and the appended claims. In those instances Where temperatures are given with respect to initial boiling points, boiling ranges, and end boiling points, it is understood that the temperatures have reference to those Which are obtained through the use of standard ASTM distillation methods. The term hydrocarbons, or hydrocarbonaceous material, connotes saturated hydrocarbons, straight-chain and branched-chain hydrocarbons, unsaturated hydrocarbons, aromatic hydrocarbons, naphthenic hydrocarbons, as Well as various mixtures of hydrocarbons such as hydrocarbon fractions and/or hydrocarbon distillates. The phrases hydrocarbons boiling within the gasoline boiling range, or gasoline boiling range hydrocarbons, and middle-distillate boiling range, have hereinbefore been defined with respect to the present specification. The process of the present invention possesses the inherent flexibility to produce a kerosene fraction in addition to the middle-distillate and gasoline boiling range fractions. The term kerosene fraction is intended to connote those hydrocarbons boiling Within the range of from about 400 F. or 425 F. to about 500 F., or about 550 F.

Similarly, with respect to the various catalytic composites employed Within the reaction zones of the process of the present invention, the term metallic component, or catalytically active metallic component, is intended to encompass those components of the catalyst which are employed for their hydrorefining, hydrogenation and/ or hydrocracking activity. In this manner, the catalytically active metallic components are distinguished from those components which are employed as the carrier material, or the acidic cracking component, or both. As hereinafter set forth in greater detail, the process of the present invention utilizes particular catalytic composites in combination with particular operating conditions.

The present invention involves a process for producing hydrocarbons which boil at temperatures within the gasoline and middle-distillate boiling ranges, from those hydrocarbons which boil at temperatures above the gasoline and middle-distillate boiling ranges. Thus, the process of the present invention is generally applicable to processing petroleum-derived'feed stocks of the middle-distillate boiling range and above. Suitable charge stocks to the hydrocracking process encompassed herein include relatively high-boiling hydrocarbon distillate fractions, as gas oil fractions, lubricating and white oil stock-s; cycle stocks, slurry oils, black oil stocks, the various highboiling bottoms recovered from the fractionators generally accompanying catalytic cracking operations and referred to as heavy recycle stock; fuel'oil stocks, crude petroleum oils, reduced and/or topped crude oils, and other sources of hydrocarbons having a depreciated market demand due to the relatively high boiling points of these hydrocarbons and to the presence of various contaminating influences including nitrogenous and sulfurous compounds, and asphaltic and other heavy hydrocarbonaceous residue. Accordingly, the hydrocarbon charge stock may consist entirely of a heavy vacuum gas oil or recycle stock, boiling within the range of from about 650 F. to about 1100 F., or more. The hydrocarbonaceous material may be a light cycle oil boiling entirely within the middle-distillate or fuel oil boiling range, or it may be a vacuum gas oil having a boiling range of from about 600 F. to about 950 F. It is understood, therefore, that the process of the present invention is not strictly limited to the use of a particular hydrocarbon mixture as the charge stock, although the same is especially adaptable for processing hydrocarbons boiling at temperatures above the middle-distillate boiling range.

All of the foregoing heavy hydrocarbonaceous fractions and/or distillates generally contain high-boiling nitrogenous compounds, in addition to substantial quantities of sulfurous compounds, as contaminants. The presence of such nitrogen-containing compounds Within the hydrocarbon charge stock not only suppresses the hydrocracking activity of the catalytic composite, but also promotes the relatively rapid deactivation of the catalyti cally active components, resulting in a high degree of catalyst instability. Nitrogenous compounds exhibiting this detrimental effect, sometimes referred to herein as hydrocracking supressors, include both organic and inorganic nitrogen-containing compounds, aliphatic and aryl nitro compounds such as nitromethane, dinitromethane, and nitrobenzenes; primary, secondary and tertiary aliphatic and aryl amines, ammonium compounds, heterocyclic organic nitrogen compounds such as pyridine, carbazole, pyrrole and derivatives thereof, quinoline, etc. The deactivation of the catalytic composite, resulting from the presence of such hydrocracking suppressors within the hydrocarbon charge stock, appears to be due to the reaction of the nitrogen-containing compounds with the various catalytic components, the extent of such deactivation increasing as the process continues. Although neutralization appears to be a factor contributing to this type of deactivation of the catalyst, it is believed that the formation of a nitrogen-containing complex With the catalytic component, whereby the active centers of the catalyst, normally available to the hydrocarbon charge stock, are effectively shielded therefrom, is the more predominating effect having the greatest influence in regard to the catalyst deactivation. That is to say, the deactivating influence exhibited by nitrogenous compounds appears to be significantly greater than that exhibited by sulfurous compounds, although both exist in the hydrocarbon charge stock in excessive quantities. Furthermore, for a particular type of hydrocarbon charge stock, the higher the concentration of nitrogenous compounds, the higher the temperature required to effect a given degree of conversion to lower-boiling hydrocarbon products, all other conditions being relatively equal. As the operating temperature is increased, the tendency to produce greater quantities of gaseous, light paraffinic hydrocarbons becomes more pronounced. Another feature attendant the higher nitrogen content is that more frequent shutdowns for the purpose of catalyst regeneration and or replacement are required. Increasing the temperature, to maintain a constant, acceptable conversion to lower-boiling hydrocarbon products, results in such product quality and distribution that it becomes necessary to regenerate the catalyst, the principal factor determining the stage of the process at which regeneration must be effected, being the excessive quanity of dry gas produced.

It has been recognized for some time that the presence of excessive quantities of nitrogenous compounds, even as low as about 10 p.p.m. calculated as elemental nitrogen, will effectively poison acidic hydrocracking catalysts, and further, that the deleterious effect of the nitrogenous compounds is of a greater degree than that exhibited by the inclusion of excessive quantities of sulfurous compounds. Provisions are therefore made to eliminate and/or decrease the concentration of the nitrogenous and sulfurous compounds prior to bringing the hydrocarbonaceous charge stock into contact with the hydrocracking catalyst in the presence of hydrogen. Particularly preferred means for decreasing the quantity of nitrogenous compounds involves pretreating the hydrocarbonaceous material in a hydrorefining process, in which process such material is subjected to catalytic action at reaction conditions such that the structure of the hydrocarbon components are not substantially altered, but the nitrogenous, organically-bound components are converted into ammonia and a corresponding hydrocarbon; similarly, the sulfurous compounds are converted into hydrogen sulfide and a corresponding hydrocarbon. Although a hydrorefining pretreatment is generally preferred, other pretreating methods may be suitably employed. For example, the hydrocarbonaceous material may be intimately contacted with various acidic media such as hydrofluoric acid, fuming sulfuric acid, etc., and in those instances where the concentration of nitrogenous compounds is not highly excessive, acidic ion-exchange resins may be employed. It is understood that the particular means selected from eliminating the contaminating influence or nitrogenous and sulfuric compounds is not essential to the present invention, although the utilization of a hydrorefining re action zone is preferred from the standpoint of effective nitrogen removal to a level less than about 10.0 p.p.m., and preferably less than about 2.0 p.p.m.

Nothwithstanding that the hydrocarbonaceous material is subjected to a suitable pretreating process for the purpose of decreasing the concentration of nitrogenou and sulfurous compounds, we have found that a contaminating influence in the form of aromatic compounds remains in the charge stock. In addition to high-boiling, alkyl and aryl-substituted mononuclear aromatic hydrocarbons, such aromatic compounds include naphthalene and its various derivatives as naphthionic acid, naphthoquinone, etc.; anthracene, pyrene, triphenylene, chrysene, perylene, naphthacene, and a wide variety of alkyl-substituted polynuclear aromatic compounds. At least a portion of the foregoing aromatic compounds appear to be unaffected by the pretreating process selected to eliminate the contaminating influence of the nitrogenous and sulfurous compounds, and remain in the hydrocarbonaceous material. The deleterious effects of the presence of aromatic compounds within the pretreated charge to the hydrocracking process, are primarily two-fold: (l) certain condensed aromatics appear to be absorbed on the acidic surface without being either hydrogenated, or cracked, and the catalytic surfaces and centers are thereby actively shielded from the material being processed; (2) additionally, the hydrogenation of aromatic compounds is extremely exothermic and leads to a premature degree of hydrocracking, raising the temperature to a still higher level and causing a temperature run-away. The net result of the temperature run-away is the unabated conversion or normally liquid hydrocarbons into excessively large amounts of light paraffinic hydrocarbons. This detrimental result is not simply eliminated and/ or controlled by lowering the temperature; a certain temperature level is required to trigger the hydrocracking and at this minimum level the temperature increase resulting from the hydrogenation and/or hydrocracking of the aromatic compounds is already excessive.

The process of the present invention affords an effective method by which the adverse effects otherwise resulting from the presence of aromatic compounds within the hydrocracking charge stock, are eliminated. Briefly, this is accomplished by processing the substantially nitrogenfree (containing less than about 2.0 p.p.m.) aromaticcontaining charge stock over two separate and distinct catalysts; a hydrogenation catalyst which does not promote hydrocracking, but which is specifically tailored to effect the hydrogenation of the aromatic compounds, followed by an acidic hydrocracking catalyst which effects the conversion of the hydrocarbonaceous material into lower-boiling hydrocarbon products. The present invention may be more clearly understood through reference to the accompanying drawing which illustrates one particular embodiment thereof. It is not intended, however, that the process of the present invention be unduly limited to the embodiment so illustrated. In the drawing, various flow valves, control valves, coolers, condensers, overhead reflux condensers, pumps, compressors, knock-out pots, etc., have either been eliminated, or greatly reduced in number as not being essential to the complete understanding of the present process; The utilization of such miscellaneous appurtenances will immdiately be recognized by one possessing the requisite skill within the art of petroleum processing techniques. With reference now to the drawing, the hydrocarbonaceous material, contaminated by a substantial quantity of nitrogenous compounds of the order of about 1000 p.p.m. to about 8000 p.p.m. and sulfurous compounds in an amount of about 2.0% to about 8.0% by Weight, enters the process through line 1, is admixed with make-up hydrogen from line 2, the mixture passing through line 3 into heater 4. For the purposes of the particular embodiment illustrated in the drawing, it will be assumed that the hydrocarbonaceous material is a particularly heavy vacuum gas oil having an initial boiling point of about 650 F. and an end boiling point of about 1100 F. The mixture of hydrogen and hydrocarbonaceous material entering heater 4 is such that hydrogen is present in an amount within the range of about 1000 to about 10,000 standard cubic feet per barrel, and preferably from about 3000 to about 8000 standard feet per barrel. The function of heater 4 is to raise the temperature of the hydrogen-hydrocarbon mixture to the level desired at the inlet of the catalyst bed disposed within hydrorefining zone 6. Thus, the temperature of the material leaving heater 4 through line 5, and entering hydrorefining zone 6 will be within the range of about 500 F. to about 800 F. the maximum catalyst temperature within hydrorefining zone 6 preferably being maintained within the range of about 600 F. to an upper limit of about 850 F. Hydrorefining zone 6 will be maintained at a pressure within the range of about to about 3000 pounds per square inch gauge, and preferably at an intermediate level of about 1000 to about 2000 pounds per square inch gauge; the liquid hourly space velocity (defined as volmes of liquid hydrocarbon charge per hour, per volume of catalyst disposed within the reaction zone) will be within the range of about 0.25 to about 10.0, and preferably from about 0.5 to about 5.0. The precise operating conditions will be dependent to a great extent upon the necessary degree of the removal of nitrogenous and sulfurous compounds, in addition to the hydrogenation of olefinic hydrocarbons contained within the hydrocarbonaceous charge stock. The catalytic composite disposed within hydrorefining zone 6, hereinafter described in greater detail, appears to function more efficiently and for an extended period of time when the maximum catalyst temperature during process-- ing is less than about 850 F. Since the reactions occurring during the hydrorefining of the contaminated hydrocarbonaceous charge stock are somewhat exothermic, a rise in temperature will be experienced, and, therefore, the inlet temperature to the hydroretining catalyst bed is preferably maintained within the range of about 500 F. to about 800 F.

The total reaction product effluent from hydrorefining zone 6 is passed through line 7 into separator 3 which operates at essentially the same pressure existing in hydrorefining zone 6, but at the lower temperature of about 60 F. to about 120 F. Separator 3 serves the function of providing a substantially nitrogen-free liquid hydrocarbon phase and an ammoniacontaining gaseous phase. These are illustrated in the drawing as leaving separator 8 via lines 9 and 33 respectively. The gaseous phase in line 33 will contain a significant quantity of hydrogen sulfide, hydrogen and any light paraffinic hydrocarbons, methane, ethane and propane, resulting from the minor degree of cracking which occurs at the elevated temperatures necessary to effect acceptable removal of the nitrogen and sulfur. This gaseous phase may be treated by ion-exchange, absorption techniques, etc. for the purpose of recovering a substantially pure hydrogen stream, the latter being recycled by compressive means, not illustrated in the drawing, to combine with the hydrogen entering the process through line 2. In any event, the normally liquid hydrocarbon portion of the hydrorefining zone eiiiuent, leaving separator 55 through line 9, is substantially nitrogen-free, containing less than about 10 ppm. of nitrogenous compounds, calculated as elemental nitrogen, and preferably less than 2.0 ppm. However, as hereinbefore stated, this normally liquid hydrocarbon fraction contains a significant quantity of monoand particularly polynuclear aromatics which must necessarily be eliminated and/or greatly reduced in concentration in order to carry out an efficient, acceptable hydrocracking process.

After being admixed with additional hydrogen from line 11, and recycle hydrogen from line 19, the source of which is hereinafter set forth, the normally liquid bydrocarbons in line 9 are passe into heater 10 wherein the temperature thereof is raised to a level above about 300 F. The hydrogen-hydrocarbon mixture in line 9, entering heater 10, is such that the hydrogen is present in 21 mol ratio, to aromatic nuclei, greater than about 4: 1. The precise temperature to which the mixture of hydrogen and aromatic-containing hydrocarbons is heated, is such that the maximum catalyst temperature existing in hydrogenation Zone 14 is less than about 650 F.; thus, depending upon the precise quantity of aromatic hydrocarbons, the temperature, to which the mixture in line 9 is heated, will be within the range of about 300 F. to about 600 F. The mixture passes through line 12 into hydrogenation zone 14 the latter being maintained at a pressure of from about 300 to about 3000 pounds per square inch gauge, the liquid hourly space velocity being from about 1.0 to about 5.0. The description of the hydrogenation catalyst disposed in hydrogenation zone 14, comprising a platinum group metallic component, a non-siliceous, non-acidic carrier material and at least one metallic component selected from the group consisting of alkali and alkaline-earth metals, is hereinafter described in greater detail. The primary function of the catalyst in hydrogenation zone 14 is to effect the saturation of any monoand polynuclear aromatics remaining in the pretreated hydrocarbonaceous material after processing through hydrorefining zone 6. A relatively insignificant quantity of li ht paraifinic hydrocarbons may be produced within hydrogenation zone 14 as a result of the dealkylation of at lea t a portion of the alkyl-substituted aromatic compounds.

As indicated in the drawing, hydrocracking zone 15 is maintained within the reaction chamber distinctly sep arated from hydrogenation zone 14, the total etiluent from the latter passing immediately into contact with the hydrocracking catalyst disposed in the lower zone. Obviously, hydrocracking reaction zone 15 will be maintained under essentially the same pressure as that imposed upon hydrogenation zone 14, being Within the range of from about 300 pounds per square inch to about 3000 pounds per square inch gauge. Depending upon the precise quantity of catalyst disposed therein, the liquid hourly space velocity through hydrocracking zone 15 will be within the range of from about 1.0 to about 15.0, the quantity of hydrogen being from about 1000 to about 8000 standard cubic feet per barrel. The hydrocracking zone effluent passes through line 17 into separator 18 from which the normally liquid hydrocarbon portion is withdrawn via line 22. A hydrogen-rich gaseous phase, containing a relatively minor quantity of methane, ethane and propane, is removed from separator 18 via line 19 wherein the same is recycled to combine with the hydrorefined liquid efiluent in line 9. In order to maintain control of the operating pressure imposed upon the reaction chamber comprising upper hydrogenation zone 14 and lower hydrocracking zone 15, at least a portion of the gaseous phase in line 19 is vented from the system through line 20 containing pressure control valve 21. Withdrawal of this gaseous phase from the system also prevents the continuing build-up of light paraflinic hydrocarbons which would adversely affect the concentration of hydrogen passing through the hydrogenation and hydrocracking zones, and also adversely increase the space velocity therethrough.

A normally liquid hydrocarbon product efiluent from hydrocracking zone 15' is removed from separator 18 via line 22, and is passed therethrough into fractionator 23 at a point just above center-well 27. Fractionator 23 is operated in such a manner as to provide the desired breakdown of the total hydrocracked product effluent. For example, as indicated in the drawing, light hydro carbons such as butanes and pentanes are removed from the uppermost extremity of fractionator 23 through line 24. From a point just above center well 25, the remaining gasoline boiling range hydrocarbons, having an end boiling point of about 400 F. to about 425 F., are removed via line 26; in those instances where economic considerations dictate the production of middledistillate boiling range hydrocarbons, having a boiling range of from about 400 F. or 425 F. to about 650 F., the same are Withdrawn through line 28 containing valve 29. That portion of the hydrocracked product efiiuent boiling above the middle-distillate boiling range, or at a temperature above about 650 F., are removed from fractionator 23 via line 3, and are passed either through line 16 containing valve 31 into the reaction chamber at a point intermediate hydrogenation zone 14- and hydro cracking zone 15, or through line 13 containing valve 32 to combine with the hydrorefined product efiluent and hydrogen in line 12; where desired, primarily for the purpose of operational control, at least a portion of the hydrocracked product efiluent boiling above 650 F. may be passed through that portion of line 3 containing valve 30 to combine with the fresh hydrocarbonaceous charge stock entering the system via line 1. The preferred mode of operation involves passing the hydrocarbonaceous material boiling above about 650 F. from fractionator 23 through line 16 into the reaction chamber at a point intermediate the hydrogenation and hydrocracking zones, valves 30 and 32 being in closed position. In this manner, the heavier products (boiling above about 650 F.) are recycled, but without the necessity of additional processing through the hydrogenation zone, thereby diluting the fresh feed and increasing the space velocity therethrough. That is, the fresh feed, being the hydrorefined product efiluent, passes through both the hydrogenation zone 14 and hydrocracking zone 15, whereas the recycle material is fed directly to hydrocracking zone 15. With respect to the foregoing discussion of the embodiment illustrated in the accompanying drawing, it is seen that the hydrogenation of the monoand polynuclear aromatic compounds, remaining in the hydrocarbonaceous material following the pretreatment thereof for the removal of nitrogenous and sulfurous compounds, is effected at conditions which preclude the existence of a temperature run-away otherwise resulting if the hydrocracking reactions are effected in the presence of these aromatic compounds. In addition to eliminating polynuclear aromatic compounds as one cause of a rapid catalyst deactivation, the danger of an extremely high-temperature localized catalyst deactivation and excessive production of light paraffinic hydrocarbons is virtually eliminated. It will be further noted by those possessing skill within the art of petroleum processing techniques, that the particular arrangement of the hydrogenation and hydrocracking zones within the reaction chamber, and the operating conditions imposed thereon, have the additional dvantage of eliminating heaters, condensers, coolers, and other processing equipment.

Many modifications of the illustrated embodiment may be made, and it is not intended that such modifications remove the resulting process flow outside the broad scope of the present invention as defined in the specification and appended claims. For example, water may be injected into line 7 being admixed therein with the total hydrorefining zone effluent, and thereafter subjected to separation in separator 8 such that ammonia is absorbed and removed within a water-phase, hydrogen sulfide and other gaseous components being removed in a gaseous phase, and the normally liquid hydrocarbons separately recovered through line 9. On the other hand, the total hydrorefining zone effluent may be passed into a suitable separation zone countercurrently to a liquid absorbent whereby the ammonia, hydrogen sulfide, and various gaseous components other than hydrogen are effectively removed therefrom. Still another modification would involve separately treating the gaseous phase in either line 33 or line 19 for the purpose of recovering therefrom a substantially pure hydrogen stream which may be utilized in admixture with the fresh hydrogen entering the process through either line 2 or line 11.

As hereinbefore set forth, the majority of hydrocarbon fractions and/or distillates which are subjected to a hydrocracking process for the purpose of producing lowerboiling hydrocarbon products contain excessive quantities of nitrogenous and sulfurous compounds. The preferred means for decreasing the concentration of such contaminating influences is the catalytic hydrorefining of the charge stock, whereby the contaminants are converted into ammonia, hydrogen sulfide and hydrocarbons. A suitable catalyst for use in the hydrorefining reaction zone of the present process is necessarily non-sensitive to the presence of substantial quantities of these contaminating influences; that is, the catalyst must necessarily be such that rapid deactivation is not effected as a result of the presence of nitrogen and sulfur while at the same time possessing the propensity for effecting the destructive removal tiereor'. Furthermore, it is preferred that the hydrorefining catalytic composite does not possess the characteristic of being capable of effecting excessive hydrocracking reactions to produce lower-boiling hydrocarbon products in the presence of the nitrogen and sulfur-containing compounds, the ammonia and the hydrogen sulfide. A catalyst comprising comparatively large quantities of molybdenum, calculated as the element, composited with a suitable carrier material, such as alumina, is very efiicient in carrying out the desired operation. The hydrorefining catalyst may comprise metallic components selected from Group VI-A and the iron-group of the Periodic Table, and, therefore, comprise molybdenum, chromium, tungsten, iron, cobalt, nickel, mixtures of two or more, etc., the preferred catalytic composite comprises from about 4.0% to about 45.0% by weight of molybdenum, and utilizes a carrier material which is predominantly alumino. Intermediate quantities of molybdenum will suffice for the pretreatment of the greater majority of charge stocks, and

will be within the range of about 10.0% to about 25.0% by weight. Furthermore, although it is desirable to avoid excessive hydrocracking (splitting of a hydrocarbon molecule at a carbon to carbon bond), other refractory inorganic oxides may be employed in relatively minor quantities, from about 1.0% to about 40.0%, to enhance the ability of the catalyst to split-off nitrogen and/or sulfur from the hydrocarbon molecules. Such other refractory inorganic oxide material includes silica, zirconia, magnesia, titania, thoria, boria, hafnia, etc., and the use thereof has been shown to be extremely selective regarding hydrocracking, whereby excessive production of light paraffinic dry gas is avoided. Acceptable results have been achieved utilizing a carrier material consisting of 88.0% by weight of alumina and 12.0% by weight of silica. In

rany instances wherein a particular degree of hydrocracking activity is desirable, the hydrorefined catalyst may contain from about 0.2% to about 10.0% by weight of an irongroup metallic component. Thus, the catalyst utilized in the hydrorefining reaction zone may comprise from about 10.0% to about 25.0% by weight of molybdenum, from about 1.0% to about 6.0% by weight of nickel composited with alumina; 6.0% by weight of molybdenum,

1.5% by weight of nickel, 0.25% by weight of cobalt composited with an alumina-silica carrier material in which the silica is present in an amount of about 1.0% to about 12.0%; 1.1% by weight of cobalt, 5.6% by weight of molybdenum on a carrier material consisting essentially of 100% by weight of alumina, etc.

The catalytic composite, for utilization in the hydrorefining reaction zone, may be manufactured in any suitable manner, and it is understood that the precise method is not considered to be a limiting feature of the present invention. A particularly advantageous method utilizes an impregnating technique; thus, where the catalyst is to contain both nickel and molybdenum, the method of preparation involves first forming an aqueous solution of watersoluble compounds of the desired metals, such as nickel nitrate, nickel carbonate, ammonium molybdate, molybdic acid, etc. The preformed alumina particles, serving as the carrier material, are commingled with the aforementioned aqueous solutions, and subsequently dried at a temperature of about 200 F. The ried composite is then oxidized in an oxidizing atmosphere such as air, at an elevated temperature of from about 1100 F. to about 1700 F., and for a period of from about 2 to about 8 hours or more. It is further understood that the impregnatrng technique may be effected in any suitable manner; thus, the carrier material may be impregnated first with the molybdenum-containing solution, dried and oxidized, and subsequently impregnated with the nickel-containing solution. On the other hand, the two aqueous solutions may be first intimately commingled with each other, the carrier material subsequently impregnated in a single step. Following the impregnation of the carrier material, and the drying and high-temperature oxidation techniques, the catalytic composite may be treated in any manner to convert the metallic components into a particularly desired form. Thus, although the quantities of the metallic components are computed on the basis of the elemental metals, the same may exist as the elemental metals, or as the oxides, sulfides, etc. thereof.

A feature of the present invention resides in the partrcular catalytic composite employed in the upper hydrogenation zone of the reaction chamber. In order to avoid hydrocracking reactions in the presence of the monoand particularly polynuclear aromatic compounds, the catalytic composite is characterized as being nonacidic. Thus, the catalytically active metallic components are composited with a non-siliceous refractory inorganic oxide which does not contain excessive quantities of acid-acting components. Such acid-acting components would include silica and other similar refractory inorganic oxides, and components selected from the halogen family, particularly fluorine and/or chlorine. Thus, the hy- 13 drogenation zone of the present invention makes use of a non-acidic, non-siliceous refractory inorganic oxide carrier material which is preferably composited with a platinum-group metal component and an alkali metal and/or alkaline-earth metal component. It is understood that the platinum-group metal and/or other metallic component may be present either as the element, or as a chemical compound, or in physical association with the other catalytic components; in any event, the concentrations of such metallic components, as herein stated, are calculated on the basis of the elemental metal. The platinum-group metallic component may be platinum, palladium, ruthenium, rhodium, iridium, etc. It appears that the utilization of either platinum and/ or palladium yields more advantageous results, and these platinumgroup metals are, therefore, preferred. In general, the platinum-group component will be utilized in a concentration of from about 0.01% to about 5.0% by weight of the final catalyst, although suitable catalysts may be manufactured to contain intermediate quantities within the range of about 0.1% to about 2.0% by weight. The alkali metal and/or alkaline-earth metal component, such as cesium, lithium, rubidium, sodium, calcium, magnesium, and/or strontium, will be employed in a concentration of not more than about 5.0% by Weight of the catalyst; in order to achieve a proper balance between inhibiting the occurrence of side reactions, and imparting the desired degree of stability to the platinumgroup metal-containing catalyst, it is preferred to employ the alkali and alkaline-earth metals in significantly lower concentrations. Therefore, they will be present in a concentration witlun the range of from about 0.01% to about 0.7% by weight, calculated as the element thereof.

The hydrogenation catalyst, comprising, for example, platinum, lithium and alumina, may be prepared in any suitable manner, and it is further understood that the particular method of manufacture is neither essential to, nor limiting upon the present invention. In general, alumina may be prepared by reacting a suitable alkaline reagent including ammonium hydroxide, ammonium carbonate, etc., with a salt of aluminum including aluminum chloride, aluminum sulfide, aluminum nitrate, etc. The substances are intimately admixed under conditions to form aluminum hydroxide which, upon subsequent heating and drying, will form alumina. The platinum-group metallic component is composited in any suitable manner, and generally by way of an impregnating procedure wherein a water-soluble platinum and/or paladium compound is employed. The alkali metal, or alkaline-earth metal, is added as an aqueous solution of a suitable salt thereof, and thus may comprise a chloride, sulfate, nitrate, etc. of lithium, sodium, calcium, rubidium, magnesium, strontium and/ or cesium, etc. It is generally advisable to introduce the platinum-group metallic component at a later step of the catalyst preparation in order that this relatively expensive metallic component will not be lost due to subsequent processing in the washing and purification treatments. After all of the catalytic components have been composited, the catalyst is dried at a temperature of about 200 F., for a period of from about 2 to about 24 hours. Rapid drying is to be avoided since a sudden evolution of gas will cause the catalyst particles to rupture and otherwise become strained. Following the drying of the catalyst, it is subjected to a calcination treatment at a temperature of from about 800 F. to about 1100 F., for a period of from about 2 to about 12 hours, and in an atmosphere of air.

The hydrogenation of the monoand polynuclear aromatic compounds will be effected at a temperature above about 300 F. and selected such that the maximum catalyst temperature will not exceed about 650 F. The precise temperature to which the hydrorefined product efiuent and hydrogen are heated will, of course, be dependent upon that quantity of aromatic compounds which must necessarily by hydrogenated. Since the quantity of hydrogen in admixture with the hydrorefined product efiiuent entering the upper zone of the reaction chamber must be sufficient for the purpose of hydrogenating the aromatic compounds as Well as effecting acceptable hydrocracking to produce lower-boiling hydrocarbon products, the amount of hydrogen is based upon the quantity required for the hydrocracking reactions. That is, the hydrogen will be present in an amount within the range of about 1000 to about 8000 standard cubic feet per barrel of liquid hydrocarbon charged to the reaction chamber, above that required to hydrogenate the aromatic compounds; the hydrogenation of the aromatic compounds generally requires hydrogen to be present in an amount greater than a 4:1 mol ratio with respect to the aromatic nuclei.

Catalytic composites which comprise at least one metallic component selected from Groups VI-A and VIII of the Periodic Table, and a composite of silica and from about 10.0% to about 90.0% by weight of alumina, constitute hydrocracking catalysts for use in the hydrocracking reaction zone of the process of the present invention. Such catalysts have a relatively high activity with respect to the conversion of hydrocarbons boiling Within and above the middle-distillate boiling range, into hydrocarbon products boiling within the gasoline boiling range. Furthermore, in those instances where the hydrocarbonaceous material boils almost entirely at temperatures exceeding the middle-distillate boiling range (650 R), such catalysts readily adapt themselves for utilization in producing both middle-distillate boiling range hydrocarbons and gasoline range boiling hydrocarbons.

The synthetically-produced solid carrier material, for utilization in the lower hydrocracking zone of the reaction chamber, may be made in any suitable manner including separate, successive or coprecipitation methods. For example, alumina may be prepared by adding a reagent such as ammonium hydroxide, ammonium carbonate, etc., to a salt of aluminum such as aluminum chloride, aluminum nitrate, aluminum acetate, etc., in an amount which forms a precipitate of aluminum hydroxide. Aluminum chloride is generally preferred as the aluminum salt for convenience in subsequent washing and filtering procedures, and, furthermore, appears to give the best results with respect to the ultimate physical characteristics of the carrier material. The resulting am monium hydroxide precipitate is, upon drying, converted to alumina. Although alumina particles may take the form of any desired shape such as spheres, pills, pellets, cakes, extrudates, powder, granules, briquettes, etc., a particularly preferred form is the sphere, and alumina spheres may be continuously manufactured by passing droplets of an alumina-containing hydrosol into an oil bath maintained at an elevated temperature. Similarly, silica may be prepared in any suitable manner, one particular method being to commingle water glass and a mineral acid under conditions which precipitate a silicacontaining hydrogel. The silicia hydrogel is subsequently washed with water containing a small amount of a suitable electrolyte for the purpose of removing sodium ions. Oxides of other compounds may be prepared by reacting a basic reagent such as ammonium hydroxide, ammonium carbonate, etc., with an acid-salt solution of the metal such as, for example, the chloride, sulfate, nitrate, etc., or by adding an acid to an alkaline-salt of the metal such as, for example, commingling surfuric acid with sodium aluminate, etc. Usually the metal oxide will be washed and filtered, which may be accomplished in the same or separate steps, and may be effected in the presence of an acid or an alkaline material as desired. When advantageous to prepare the catalyst in the form of particles of uniform size and shape, this may be readily.accomplished by grinding the partially dried metal oxide cake with a suitable lubricant such as stearic acid, resin, graphite, polyvinyl alcohol, etc., and subsequently forming the particles in any suitable pelleting or extrusion apparatus.

aaoaess The hydrocracking catalyst carrier material comprises at least two refractory inorganic oxides, preferably alumina and silicia, and may be prepared by separate, successive or coprecipitation methods. In the separate precipitation method, the oxides are precipitated separately and then mixed in the wet state; when successive precipitation methods are employed, the first oxide is precipitated as hereinbefore set forth, and the wet slurry, either with or without prior washing, is composited with a salt of the other component. Precipitation of the oxide thereof is effected by the addition of a suitable alkaline or acidic material to the resulting slurry. When the hydro-- cracking catalyst carrier material comprises silicia and alumina, and/or silica, alumina and zirconia, it is preferentially manufactured by commingling an acid such as hydrochloric acid, sulfuric acid, etc., with commercial water glass under conditions to precipitate silica, washing the precipitate with acidulated water or other means to remove sodium ions, subsequently commingling with an aluminum salt such as aluminum chloride, and/or some suitable zirconium salt, etc., and either adding a basic precipitant such as ammonium hydroxide, or form ing the desired oxide or oxides through the thermal decomposition of the salt, as the case may be. As with the catalytic composites disposed with the hydrorefining reaction zone and the upper hydrogenation zone of the reaction chamber, the particular means utilized for the manufacture of the catalyst disposed within the lower hydrocracking zone is not considered to be a limiting feature of the process of the present invention.

The catalytically active metallic component, and/or components, of the catalyst disposed within the hydrocracking zone of the reaction chamber, is composited with the aforementioned acid-acting carrier material. The metallic components are generally employed in an amount of from about 0.1% to about 20.0% by weight of the total catalyst. The catalyst comprises at least one metallic component selected from the metals of Groups VI-A and VIII of the Periodic Table, and includes, therefore, platinum, palladium, nickel, iron, cobalt, molybdenum, tungsten, chromium, ruthenium, rhodium, iridium, etc., and these may be incorporated with the acid-acting cracking carrier material in any suitable manner. Inpregnating techniques may be advantageously employed by first forming an aqueous solution of a water-soluble compound of the desired metals such as platinum chloride, palladium chloride, nickel nitrate, ammonium molybdate, moylbdic acid, chloroplatinic acid, chloropallatic acid, etc., and commingling the solution with a carrier material in a steam drier. Other suitable metal-containing solutions which may be utilized are colloidal solutions or suspension including the desired metal cyanides, metal hydroxides, metal oxides, metal sulfides, etc. Where such solutions are not water-soluble at the temperature employed, other suitable solvents such as alcohols, ethers, etc., may be utilized. The catalytic composite, after all of the catalytic components are present therein, is dried for a period from about 2 to about 8 hours or more, and subsequently oxidized in an oxidizing atmosphere such as air, at an elevated temperature of about 1100 F. to about 1700 F. and for a period of from about 1 to about 8 hours or more. In many instances, following the hightemperature oxidation procedure, it is desirable to reduce the catalyst, in the presence of hydrogen, for a period of from about one-half hour to about one hour at a temperature which is in the range of about 700 F. to about 1100 F. Where desired, the catalyst may be reduced in situ, that is, by placing the catalyst within the second reaction zone, and subjecting the same to an imposed hydrogen purge of the system at a temperature of about 700 F.

As previously set forth, it is preferred that the catalytic composite employed in the lower hydrocracking zone of the reaction chamber comprise at least two refractory inorganic oxides, and preferably alumina and silica.

When silica and alumina are employed in combination, the latter will be present within an amount of from about 10% to about 90% by weight. Excellent results have been achieved through the utilization of the following silica-alumina composites; 88% by weight of silica and 12% by weight of alumina, by weight of silica and 25% by Weight of alumina, 63% by weight of silica and 37% by weight of alumina, 88% by weight of alumina and 12% by weight of silica. The total quantity of the catalytically active metallic components will lie within the range of from about 0.1% to about 20.0% by weight of the total catalyst. The Group VI-A metal, such as chromium, molybdenum, or tungsten, when utilized in the hydrocracking catalyst, is usually present in quantities within the range of from about 0.5% to about 20.0% by weight of the catalyst. The Group VH1 metals, which may be divided into two sub-groups, are present in an amount of from about 0.1% to about 10.0% by weight of the total catalyst. When an iron sub-group metal such as iron, cobalt, or nickel, is employed, it is present in an amount of from about 0.2% to about 10.0% by weight, and preferably from about 1.0% to about 6.0%, whereas the platinum-group metal such as platium-palladium, iridium, rhodium, etc., is present in an amount within the range of from about 0.1% to about 5.0% by weight of the total catalyst. When the metallic component of the hydrocracking catalyst consists of both a Group VI-A and a Group VIII metal, it will contain metals of these groups in a ratio of from about 0.05:1 to about 5.0:1 of the Group VIII metallic components to the Group VI-A metallic components. Suitable catalytic composites, for utilization in the hydrocracking zone, comprise the following, but not by way of limitation: 6.0% by weight of nickel and 0.2% by weight of molybdenum; 1.8% by weight of nickel and 16.0% by weight of molybdenum; 6.0% by weight of nickel; 0.4% by weight of palladium; 6.0% by weight of nickel and 0.2 by weight of platinum; 6.0% by weight of nickel and 0.2% by weight of iron; 0.4% by weight of platinum; 6.0% by weight of nickel and 12.0% by Weight of molybdenum, etc.

In many instances, particularly when the catalytically active metallic components comprise metals selected from the platinum-group of Group VIII of the Periodic Table it will be desirable to include a halogen component to impart an additional acid-acting function to the hydrocracking catalyst. Such halogen is generally selected from the group of chlorine and/or fluorine, and will be present within the composite in an amount of from about 1.0% to about 8.0% by weight, calculated as the element, although referred to as combined halogen. The halogen component may be composited within the catalyst in any suitable manner including the utilization of volatile salts such as ammonium chloride and ammonium fluoride, or'acids such as hydrochloric acid and hydrofluoric acid, or during the manufacture of the carrier material as when aluminum chloride is employed as the source of the aluminum.

It is understood that the broad scope of the present invention is not to be unduly limited to the utilization of a particular catalyst having a particular concentration of components, a particular means for the manufacture of the same, or specific operating conditions other than those previously set forth. The utilization of any of the previously mentioned catalytic composites, at operating conditions varying within the limits hereinoefore set forth does not necessarily yield results equivalent to the utilization of other catalytic composites employed under other operating conditions. The precise nature of the catalyst employed, and the exact operating conditions in the various reaction zones, are at least partially dependent upon the physical and/or chemical characteristics of the high-boiling hydrocarbon fraction being subjected thereto. Furthermore, the operating conditions will be dependent upon the quality and quantity of the normally liquid hydrocarbon product desired as the end result. Through the utilization of the process of the present invention, greater concentrations of hydrocarbons boiling within normal gasoline and middle-distillate boiling ranges are produced from those hydrocarbons boiling at temperatures in excess of the normal gasoline and middledistillate boiling ranges. Furthermore, it is possible to effect such conversions over an extended period of time due to the greater degree of stability imparted to the various catalytic composites, as a result of the particular decontamination of the charging stock as hereinbefore described. A degree of flexibility within the process is afforded, with the result that greater concentrations of gasoline boiling range hydrocarbons may be subsequently produced from the middle-distillate boiling range hydrocarbons, contained within the product efiiuent, by recycling the latter to combine with the hydrocarbon charge stock. The overall picture indicates extended catalyst stability over a prolonged period of time, in addition to a substantial reduction in the quantity of light paraffinic hydrocarbons otherwise resulting from the nonselective, uncontrolled hydrocracking of hydrocarbons boiling at temperatures in excess of the normal gasoline boiling range, and particularly such hydrocracking when effected in the presence of polynuclear aromatic compounds. The process of the present invention yields a gasoline boiling range hydrocarbon product which is substantially completely free from unsaturated straight and branched-chain hydrocarbons, and is, therefore, extremely well suited as the charge material to a subsequent catalytic reforming process for the purpose of further increasing the octane rating thereof. Although the method of the present invention, and the operating conditions utilized therein, are such that the effective life of the catalytic composites, is prolonged over an extended period of time, catalyst regeneration may eventually become desired due to the natural deterioration of the catalytically active metallic components thereof, inherently resulting from the extended operation. In general, the catalytic composites may be readily regenerated by contacting the deactivated catalyst with a free oxygen-containing gaseous material, such as air, at temperatures within the range of about 700 F. to about 1400 F., for the purpose of removing coke and other heavy hydrocarbonaceous material therefrom. The resulting metal oxide may then be converted to a substantially reduced state through the utilization of a reducing atmosphere such as hydrogen, and, with respect to those catalytic composites utilizing combined halogen, the halogen may be replaced through the utilization of hydrogen halide, a hydrogen-containing gaseous phase, etc.

With respect to the conversion of the hydrocarbonaceous material into lower-boiling hydrocarbon products being eifected in the lower zone of the reaction chamber, high conversions of the charge material into gasoline boiling range hydrocarbons are generally effected at temperatures of about 600 F. to about 950 F. Complete conversion into substantially fuel oil (middle-distillate boiling range hydrocarbons) occurs at about 400 F. to about 500 F.; that is, higher temperatures are required to obtain a greater proportion of the gasoline boiling range hydrocarbons. The range of operating temperatures employed in the hydrocracking zone, to achieve a particularly desired result will vary to a certain extent, with the type of carrier material employed, with the character of the charge stock and the residual quantity of polynuclear aromatic compounds therein. In addition, the precise temperature will depend upon, and may be correlated with the liquid hourly space velocity as well as the current instantaneous life of the catalyst. The operating temperatures will generally be within the range of about 400 F. to about 950 F., and preferably from about 500 F. to about 800 F. The precise operating temperature may be readily determined by those skilled in the art upon considering the character and coniposition of the catalytic composite, the liquid hourly space velocity and/or the physical and chemical characteristics of the high-boiling hydrocarbon charge stock, and the desired end result. In any event, the quantity of light paratiinic hydrocarbons, methane, ethane, and propane at any particular conversion level is extremely low. The present process achieves efiicient conversions with minimum losses from the deposition of coke and carbonaceous material, and the production of undersirable light parafiinic hydrocarbons. Although the temperature and liquid hourly space velocity are the main factors atfectin the degree of conversion into hydrocarbon products boiling within the normal and middledistillate boiling ranges, at a given temperature level the liquid hourly space velocity does not substantially affect the quantity of dry gas produced. In addition, the primary effect of varying the hydrogen to hydrocarbon mol ratio through the hydrogenation and hydrocracking zones, and the hydrogen pressure imposed thereupon, is the effect upon the amount of coke and carbonaceous material produced. Notwithstanding lower pressures and/ or lower hydrocarbon mol ratios, both as hereinbefore specified, there is very little coke formation otherwise experienced at the chosen operating conditions when processing a hydrocarbonaceous material in which the polynuclear aromatics exist in high concentrations, It will be recognized, therefore, that the variables must be primarily correlated to produce high yields of gasoline and middle distallate hydrocarbons, and minor quantities of dry gas, and that such correlations may be readily made by one possessing skill in the art of petroleum processing.

The following examples are given to illustrate further the process of the present invention, and to indicate the benefits to be afforded through the utilization thereof. It is understood that the examples are given for the sole purpose of illustration, and are not considered to limit the generally broad scope and spirit of the appended claims. The charge employed to illustrate the process of the present invention, and to indicate the benefits afforded as a result of the hydrogenation of the polynuclear aromatic hydrocarbons, prior to subjecting the hydrocarbonaceous material to hydrocracking reactions, was a northwestern light cycle oil having the analysis as shown in the following TABLE I.LIGHT CYCLE OlL CHARGE STOCK As Received Hydrorefined Gravity, API 60 F ml. ASTM Distillation, F.'.

Initial Boiling Point End Boiling Point Sulfur, wt. percent".-. Nitrogen, p.p.m Polynuclear Aromatics (p cene) as anthraexperiencing rapid catalyst deactivation and extremely low conversion into hydrocarbons boiling within the normal gasoline boiling range (having an end boiling point of 400 F. to about 425 F.). Therefore, the light cycle oil was subjected to hydrorefining for the purpose of effecting the destructive removal of the high-boiling sulfurous and nitrogenous compounds.

The catalyst employed in the hydrorefining process was a composite of 11.3% by weight of molybdenum, 4.2% by weight of nickel and 0.05% by weight of cobalt, all of which had been composited by way of impregnating techniques with a carrier material comprising 88.0% by weight of alumina and 12.0% by weight of silica in the form of A -inch spheres. Following the drying of the impregnated spherical particles, the composite was subjected to the high-temperature oxidation treatment hereinbefore described; in this particular instance it was desired that the catalytically active metallic components exist within the composite as the sulfides thereof, and, therefore, the oxidized composite was sulfided at a temperature of about 750 F. in an atmosphere containing hydrogen sulfide. The hydrorefining conditions, under which the light cycle oil was processed, were 0.5 liquid hourly space velocity, a pressure of 900 pounds per square inch gauge, and an inlet temperature to the catalyst bed of 658 F (resulting in a maximum catalyst temperature of 761 F.), in the presence of 10,000 standard cubic feet of hydrogen per barrel of liquid hydrocarbon charge. It is recognized that these conditions are extremely severe, and, as indicated in Table I, effected a slight change in the boiling range and gravity of the light cycle oil. However, it was desired, for the purpose of illustration, to produce an ultra-clean hydrocarbon mixture to be subjected to hydrocracking. As further indicated in Table I, notwithstanding the severe hydrorefining conditions, and extremely large quantity of hydrogen, the hydrorefined liquid product contained polynuclear aromatics, calculated as anthracene, in an amount of 75 ppm.

Example I The charge stock employed in this example was the hyd-rorefined northwestern light cycle oil, containing 75 ppm. of polynuclear aromatics (as anthracene), as indicated in the foregoing Table I., The hydrocracking catalytic composite was prepared utilizing a carrier material of silica and alumina, containing 75% by weight of silica, in the form of /sinch by Aa-inch cylindrical pills. The catalyst was prepared by impregnating 276 grams of the alumina-silica pills with 240 cc. of an aqueous solution containing 88.5 grams of nickel nitrate hexahydrate (5.0% by weight of nickelon the finished catalyst). Following the impregnation and drying, the catalyst was calcined for a period of 3 hours at a temperature of 1300 F. in a vertical furnace utilizing dry nitrogen at a rate of about /2 cubic feet per hour.

The hydrocracking reaction zone was maintained under a hydrogen pressure of about 1500 pounds per square inch gauge, a temperature of about 600 F with a liquid hourly space velocity of 2.0 through the catalyst. As indicated in Table II, after a catalyst life of 16 hours at a hydrogen recycle rate of 10,000 standard cubic feet per barrel of hydrocarbon charge, the norma-lly liquid portion of the product efliuent indicated a gravity, API at 60 F., of 60.0, and a conversion to hydrocarbons boiling below 400 F., of 84.0% by volume. As indicated under period B, notwithstanding an increase in the hydrogen recycle rate to 20,000 standard cubic feet per barrel, at the end of 40 hours, or 24 hours following period A, the gravity of the normally liquid hydrocarbon portion of the product efiluent was 35.4, and the conversion to gasoline boiling range hydrocarbons had decreased to 10.0% by volume.

Example II The catalyst employed in this example consisted of 0.4% by weight of palladium composited with the silicaalumina spheres previously described, containing, however, 1.9% by weight of combined fluoride, calculated as elemental fluorine. The catalyst was prepared by impregnating 468 grams of the silica-alumina carrier material with a solution of 26.2 grams of hydrofluoric acid (48.0% by weight of hydrogen fluoride), diluted to 350 cc. and admixed with 57.5 cc. of a 28.0% by weight solution of ammonia. After impregnation and drying, the catalyst was oxidized for a period of 1 hour at a temperature of 1000 F. grams of the fluorided alumina-silica was impregnated with cc. of an aqueous solution containing 29 cc. of palladium chloride (containing 0.018 gram of palladium per cc.). After impregnation and drying, the catalyst was calcined for a period of 1 hour at a temperature of 1300 F.

In this example, the processing of the hydrorefined northwestern light cycle oil was intentionally conducted at low-severity hydrocracking conditions. As shown in the following Table III, for example, the liquid hourly space velocity was 4.0, as compared to 2.0 in Example I, and the reactor maintained at a temperature of 473 F. (period C) and 491 F. (period D). As indicated by the analyses obtained on the normally liquid portion of the product efliuent, the hydrocracking catalyst deactivated at a relatively rapid rate. The volume percent conversion to gasoline boiling range hydrocarbons decreased from 27.0 to 11.5, with a corresponding increase in the initial boiling point thereof from F. to 205 F. Similarly, there was a decrease in the gravity, API at 60 F., of from 42.6 to 36.3.

TABLE III.LOVV-SEVERITY HYDROCRACKING Example III In this example, the hydrorefined light cycle oil, containing 75 p.p.m. of polynuclear aromatic, as anthracene, was subjected to prehydrogenation at temperatures of from 464 F. to about 518 F., a liquid hourly space velocity of 6.0 and a pressure of 1500 pounds per square inch gauge. The catalyst employed was a non-siliceous halogen-free alumina carrier material containing 0.75% by weight of platinum and 0.274% by weight of lithium, calculated as the elements thereof. The incorporation of the platinum and lithium with the spherical alumina particles involved the simultaneous impregnation with a single aqueous solution of lithium hydroxide and chloroplatinic acid, in amounts to yield the indicated quantities, calculated as the elemental metals. The impregnated 21 spherical particles were dried over a water bath at about 210 F. and subsequently calcined for a period of hours at a temperature of about 1800 F. in an atmosphere of air. The analysis of the pre-hydrogenated, hydrorefined light cycle oil is given in the following Table IV. It is noted that the polynuclear aromatic concentration has decreased from 75 to 2.8 p.p.m., and that there has been a decrease in the quantity of nitrogen from 0.27 to 0.14

p.p.m.

TABLE IV.PRE-HYDROGENATED HYDRO- REFINED LIGHT CYCLE OIL Polynuclear aromatics, p.p.m., anthracene 2.8

The foregoing described pre-hydrogenated, hydrorefined northwestern light cycle oil was processed over a hydrocracking catalyst containing 5.0% by weight of nickel on /s-inch by As-inch silica-alumina cylindrical pills, at a temperature of 621 F., a pressure of about 1500 pounds per square inch gauge and at a liquid hourly space velocity of about 2.0. For 300 hours of operation, the gravity, API at 60 F., of the normally liquid portion of the product efiluent was virtually constant at 48.0. During the period of approximately 300 to 312 hours of on-stream operation, the ure-hydrogenated charge stock was removed and the hydrorefined (but not pre-hydrogenated) northwestern light cycle oil, as described in the foregoing Table I, was utilized as the charge stock. During the on-stream time of 300 hours to 312 hours, while the change in charge stocks was being effected, the gravity of the normally liquid product effluent decreased from 48.0 to 42.0. From 312 to 330 hours of operation, the API gravity decreased from 42.0 to 38.0 and indicated continued rapid decline. At 330 hours of operation, the temperature was increased to 658 F., and was accompanied by a corresponding increase in gravity of the normally liquid hydrocarbon product of 38.0 to 46.5, and was indicating a continuing increase. From about 340 hours to about 362 hours, maintaining the temperature at about 658 F., the gravity of the product effluent had decreased from 46.5 to 41.5 and was indicating a relatively rapid decline.

A continuous operation was conducted wherein the hydrorefined northwestern light cycle oil was pre-hydrogenated utilizing the platinum-lithium catalyst at a pressure of 1500 pounds per square inch gauge and 4.0 liquid hourly space velocity, accompanied by a hydrogen recycle rate of 6000 standard cubic feet per barrel. The hydrogenation product efiluent was passed into the hydrocracking zone containing a catalyst of 5.0% by weight of nickel composited with an alumina-silica carrier material. The inlet temperature to the hydrocracking catalyst bed was maintained at about 648 F., 1500 pounds per square inch gauge, a recycle hydrogen rate of 6000 standard cubic feet per barrel and a liquid hourly space velocity of 4.0. Within a few hours, the operation became stable, and remained so for a period of 265 hours. During this time, the temperature of the hydrocracking zone was increased to control the gravity of the normally liquid product efiiuent at about 500 API at 60 F. The deactivation which Was experienced, as indicated by a temperature adjustment of only 1.7 F. per barrel of charge, per pound of catalyst disposed within the hydrocracking reaction zone, was that deactivation which is expected to result 22 from the normal deterioration of the catalytically active metallic components.

The foregoing examples indicate the detrimental results experienced when the hydrocracking charge stock contains polynuclear aromatic compounds. Furthermore, the benefits afforded through the utilization of the combined process of the present invention, in which the polynuclear aromatics are hydrogenated prior to effecting the hydrocracking operation, are clearly illustrated. Various modifications to the operating conditions and catalyst compositions may be made by one possessing skill within the art of petroleum refining, whereby the eifective, acceptable life of the hydrocracking catalytic composite may be further extended. It is not intended that such modifications will remove the resulting process from the broad scope and spirit of the appended claims.

We claim as our invention =1. A process for converting hydrocarbonaceous material containing aromatic compounds into lower-boiling hydrocarbon products which comprises reacting said hydrocarbonaceous material with hydrogen in contact with a nonacidic hydrogenation catalyst, at hydrogenation conditions including a temperature of at least about 300 F selected to provide a maximum catalyst temperature less than about 650 F. and to hydrogenate aromatic compounds without substantial hydrocracking of said hydrocarbonaceous material; thereafter reacting the total hydrogenated, substantially aromatic-free hydrocarbonaceous effluent from the first-mentioned step with hydrogen at hydrocracking conditions including a temperature within the range of from about 400 F. to about 950 F., and in contact with an acidic hydrocracking catalyst; the process being further characterized in that said hydrogenation catalyst comprises a platinum-group metallic component, a non-siliceous inorganic oxide and at least one metallic component from the group consisting of alkali metals and alkaline-earth metals, and said hydrocracking catalyst comprises at least one metallic component from the group consisting of the metals of Groups VIA and VIII of the Periodic Table, and compounds thereof.

2. A process for converting hydrocarbonaceous material containing aromatic compounds and less than about 10 p.p.m. of nitrogen into lower-boiling hydrocarbon products which comprises introducing said hydrocarbonaceous material, at hydrogenation conditions and in admixture with hydrogen, into a reaction chamber containing an upper zone of a non-acidic hydrogenation catalyst and a separated lower Zone of an acidic hydrocracking catalyst; said hydrogenation conditions including a temperature of at least about 300 F., selected to provide a maximum catalyst temperature less than about 650 F. and to hydrogenate aromatic compounds, without substantial hydrocracking of said hydrocarbonaceous material; said hydrogenation catalyst comprising a platinumgroup metallic component, a non-siliceous refractory inorganic oxide and at least one metallic component selected from the group consisting of alkali metals and alkaline-earth metals; reacting the total substantially aromaticfree hydrocarbonaceous eflluent from said upper zone with hydrogen at hydrocracking conditions including a temperature within the range of about 400 F. to about 950 F., and in contact with said hydrocracking catalyst; separating the resulting reaction chamber efiluent to provide a hydrocarbon fraction having an initial boiling point of at least about 400 F. and passing at least :a portion of said hydrocarbon fraction into said reaction chamber at a point intermediate said upper and lower zones.

3. The process of claim 2 further characterized in that said reaction chamber eflluent is separated to provide a first hydrocarbon fraction boiling within the gasoline boiling range and having an end boiling point of about 400 F. to about 425 F., a second fraction having an end boiling point of about 650 F. and a third fraction having an initial boiling point of at least about 650 F., and passing at least a portion of said third fraction into 23 said reaction chamber at a point intermediate said upper and lower zones.

4. The process of claim 2 further characterized in that said hydrogenation catalyst comprises alumina, from about 0.01% to about 5.0% by weight of platinum and :from about 0.1% to about 0.7% by weight of a metal selected from the group consisting of alkali and alkalineearth metals.

5. The process of claim 2 further characterized in that said hydrocra'cking catalyst comprises from about 0.2% to about 10.0% by weight of said iron-group metallic component, calculated as the element thereof.

6. A process for converting hydrocarbonaceous material containing more than about p.'p.m. of nitrogen and aromatic compounds which comprises the steps of:

(at) reacting said hydrocarbonaceous material with hydrogen, at hydrorefining conditions selected to convert nitrogenous compounds into ammonia, and in contact with a nitrogen-insensitive catalyst;

(b) separating the resulting reaction product effluent to provide a substantially nitrogen-free liquid hydrocarbon and an ammonia-containing gaseous phase;

(c) passing said nitrogen-free liquid hydrocarbon, at hydrogenation conditions and in admixture with hydrogen, into a reaction chamber containing an upper zone of a non-acidic hydrogenation catalyst and a separated lower zone of an acidic hydrocracking catalyst, said hydrogenation conditions including a maximum catalyst temperature less than about 650 F, and selected to hydrogenate aromatic compounds without substantial hydrocracking of said hydrocarbonaceous material; said hydrogenation catalyst comprising a platinum-group metallic component, a nonsiliceous refractory inorganic oxide and at least one metallic component selected from the group consisting of alkali metals and alkaline-earth metals;

(d) reacting the total substantially aromatic-free product from said upper zone with hydrogen at hydrocracking conditions and in contact with said hydrocracking catalyst;

(e) separating the resulting reaction chamber efi luent to provide a hydrocarbon fraction having an initial boiling point of at least about 400 F. and recycling at least a portion of said fraction to combine with the aforesaid substantially nitrogen-free liquid hydrocarbon.

7. The process of claim 6 further characterized in that said nitrogen-insensitive hydrorefining catalyst comprises at least one metallic component selected from the group consisting of the metals of Group VIA and the irongroup.

8. The process of claim 7 further characterized in that said hydrorefining catalyst comprises molybdenum and from about 1.0% to about 6.0% by weight of an irongroup metallic component.

9. The process of claim 6 further characterized in that said hydrorefining conditions include a temperature within the range of from about 600 F. to about 850 F.

10. A process for converting hydrocarbonaceous material containing more than about 10 ppm. of nitrogen and aromatic compounds which comprises the steps of:

(a) reacting said hydrocarbonaceous material with hydrogen, at hydrorefining conditions including a temperature within the range of from about 600 F. to about 850 F., selected to convert nitrogenous compounds into ammonia, and in contact with a nitrogen-insensitive catalyst comprising molybdenum and from about 1.0% to about 6.0% by weight of an iron-group metallic component;

(b) separating the resulting reaction product efiiuent to provide a substantially nitrogen-free liquid hydrocarbon and an ammonia-containing gaseous phase;

(0) passing said nitrogen-free liquid hydrocarbon, at

hydrogenation conditions and in admixture with hydrogen, .into a reaction chamber containing an upper zone of r a non-acidic, non-siliceous hydrogenation catalyst and a separated lower zone of an acidic hydrocracking catalyst, said hydrogenation conditions including a temperature of at least about 300 F., selected to provide a maximum catalyst temperature less than about 650 F. and to hydrogenate aromatic compounds Without substantial hydrocracking of said hydrocarbonaceous material; said hydrogenation catalyst comprising a platinum-group metallic component, a non-siliceous refractory inorganic oxide and at least one metallic component selected from the group consisting of alkali metals and alkalineearth metals;

(d) reacting the total substantially aromatic-free hydrocarbonaceous efliuent from said upper zone with hydrogen at hydrocracking conditions including a temperature Within the range of about 400 F. to about 950 F. and in contact with said acidic hydrocracking catalyst;

(e) separating the resulting reaction chamber effluent to provide a hydrocarbon fraction having an initial boiling point of at least about 400 F. and passing at least a portion of said fraction into said reaction chamber at a point intermediate said upper and lower zones.

11. The process of claim 10 further characterized in that said hydrocracking catalyst comprises at least one metallic component selected from the group consisting of the metals of Groups VI-A and VIII of the Periodic Table and compounds thereof.

12. The process of claim 10 further characterized in that said reaction chamber effluent is separated to provide a first hydrocarbon fraction boiling within the gasoline boiling range and having an end boiling point of about 400 F. to about 425 F., a second fraction having an end boiling point of about 650 F. and a third fraction having an initial boiling point of at least about 650 F., and passing at least a portion of said third fraction into said reaction chamber at a point intermediate said upper and lower zones.

13. The process of claim 10 further characterized in that said hydrogenation catalyst comprises alumina, from about 0.01% to about 5.0% by weight of platinum and from about 0.1% to about 0.7% by weight of a metal selected from the group consisting of alkali and alkalineearth metals.

14. The process of claim 10 further characterized in that said hydrocracking catalyst comprises from about 0.2% to about 10.0% by weight of an iron-group metallic component.

References Cited by the Examiner UNITED STATES PATENTS 2,671,754 3/54 De Rosset et al. 208-67 2,971,901 2/61 Halik et al. 20859 3,008,895 11/61 Hansford et al. 208112 3,023,158 2/62 Watkins 208- 3,092,567 6/ 63 Kozlowski et a1 208-57 3,132,086 5/64 Kelley et al. 208-112 ALPHONSO D. SULLIVAN, Primary Examiner.

Claims (1)

1. A PROCESS FOR CONVERTING HYDROCARBONACEOUS MATERIAL CONTAINING AROMATIC COMPOUNDS INTO LOWER-BOILING HYDROCARBON PRODUCTS WHICH COMPRISES REACTING SAID HYDROCARBONACEOUS MATERIAL WITH HYDROGEN IN CONTACT WITH A NONACIDIC HYDROGENATION CATALYST, AT HYDROGENATION CONDITIONS INCLUDING A TEMPERATURE OF AT LEAST ABOUT 300* F., SELECTED TO PROVIDE A MAXIMUM CATALYST TEMPERATURE LESS THAN ABOUT 650* F. AND TO HYDROGENATE AROMATIC COMPOUNDS WITHOUT SUBSTANTIAL HYDROCRACKING OF SAID HYDROCARBONACEOUS MATERIAL; THEREAFTER REACTING THE TOTAL HYDROGENATED, SUBSTANTIALLY AROMATIC-FREE HYDROCARBONACEOUS EFFLUENT FROM THE FIRST-MENTIONED STEP WITH HYDROGEN AT HYDROCRACKING CONDITIONS INCLUDING A TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 400* F. TO ABOUT 950* F., AND IN CONTACT WITH AN ACIDIC HYDROCRACKING CATALYST; THE PROCESS BEING FURTHER CHARACTERIZED IN THAT SAID HYDROGENATION CATALYST COMPRISES A PLATINUM-GROUP METALLIC COMPONENT, A NON-SILICEOUS INORGANIC OXIDE AND AT LEAST ONE METALLIC

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