US3544448A - Supersonic jet fuel production - Google Patents

Description

Dec. 1, 197D w JACQBS ET AL 3,544448 SUPERSONIC JET FUEL PRODUTION Filed Jan. 15, 1969 A T7'ORNEYS United States Patent flce 3,544448 Patented Dec. 1, 1970 3544448 SUPERSONIC JET FUEL PRODUCTION William L. Jacobs, Crystal Lake, and Charles H. Watkins,

Arlington Heighls, 111., assignors to Universa] Oil Products Company, Des Plaines, 111., a corporation of Dela- Filed Jan. 15, 1969, Ser. No. 791,230 Int. Cl. Cg 27/00 U.S. Cl. 208--59 6 Claims ABSTRACT OF THE DISCLOSURE APPLICABILITY OF INVENTION The present multiple-stage process is directed toward the production of supersonic jet ful from a sulfurous, aromatic, higher-boiling charge stock. More specifically, the process encompassed by the present invention afiords the simultaneous production of sonic, or standard jet fuel and supersonic jet fuel. Significantly, the jet fuel kerosene fractions, withdrawn as product streams, seldom requre further treatment in order to conform to the current specifications imposed upon sonic jet fuels, and those contemplated for the supersonics.

Suitable charge stocks, for utilization as the fresh feed in the present process, are those containing snbstantial quantities of hydrocarbons having norma1 boiling points above about 550 F., whch temperature is generally considered to be the maximum end boiling point of jet fuel kerosene fractions. Therefore, the most common charge stocks Will be vacuum gas oils and/or coker gas oils. It is understood, however, that gas oils resu1ting from a particular prior converson process are also wellsuited. The latter are those vacuum gas oils which are generally derived from the converson of extremely heavy hydrocarbonaceous material commonly referred to in the art as black oils. Exemplary of the hydrocarbonaceous material contemplated for converson into jet fue1 kerosene fractions, are a blend of coker gas oil, diesel and light gas oil having a gravity of about 27.4 API, a sulfur concentraton of about 1.36% by weight, an initial boiling point of about 401 F. and an end boiling point of about 866 F.; a Lloydminster heavy gas oil containing about 2.2% by weight of sulfur, 600 p.p.m. of ntrogen, having a gravity of about 21.5 API, an initial boiling point of 610 F. and an end boiling point of 810 F.; a Wainwright heavy gas oil having a gravity of 23.2 API, a sulfur concentraton of 1.23% by weight, contaim'ng 600 p.p.m. of nitrogen, having an initial boiling point of about 635 F. and an end boiling point of about 862 F.; a Redwater heavy gas oil having an initial boiling point of about 635 F., an end boiling point of about 855 F., a gravity of 28.1 API, and containing 0.6% by weight of sulfur and 700 p.p.m. of nitrogen; and, a virgin vacuum gas oil derived from a sonr Wyoming crude oil, the properties of which are hereafter set forth in greater detail.

Through the utilization of the present process, gas oil fraetions of the type hereinabove described, can be converted into kerosenes having acceptable jet fue1 characteristics. With respect to the motor fuel utilized in internal combnstion engines, gasolne boiling range hydrocarbons,

the crtcal properties are generally considered to be a high octane rating, a particularly specified volatlity, a low degree of olefincity, and low concentrations of contaminating influences. In contrast, many more criteria are employed in descrbng a fuel for jet engines, and even these are further restricted depending upon engine complexity, speed, crusing altitude, distance, etc. Since about 1960, the quality and classfication of jet fuels has generally followed the development of jet engines. Thus, specifications for jet fuels of particular physical and/or chemical characteristics, have resulted in jet fuels designated as JP-1, IP3, JP-4, JP-5, JP-6, JP-8, Iet-A and Jet A1, etc. Although the allowable 1imits of the characteristics, employed as criteria in determining the grate of jet fuels, differ one from the other, the selected characteristics are generally the same. These include, for example, the gravity in API, particular volumetrc distillation temperatures including the initial and end boiling points, the freeze point, flash point, luminoscity number, thermal stability, the IPT Smoke Point, the aniline point, and, most certainly, the concentraton of contaminating influences, particularly sulfur and nitrogen. It is important to note that the above-desgnated jet fuels are described in the literature as standard, or sonic jet fuels. It has already been anticipated that, although a jet fuel fracton may conform to the specifications for a given standard jet fuel, the Same will not be considered for use in future supersonic jet transports. It is contemplated that the jet fuel specifications necessitated by supersonic jet transports, will be further restricted. T0 i1- lustrate, a given kerosene fractiori currently meeting the specifications set forth With respect to J P-8 fuel, will fall outside the tentatively proposed limitatons imposed upon the supersonic jet fuels.

A comparison of the detaled requirements may be found in the ASTM Specfications for Aviation Turbine Fuels, ASTM designation, D-1655-67T. The compari 5011 is made for the jet fnels commonly referred to as Iet-A, IetA1 (both of which are also referred to as J P-5) and J et-B (also designated as J P-8). Sorne of the more pertinent property requrements are, for convenience, reproduced in the following Table 1.

TABLE I.STANDARD J'E'l FUEL PROPERTY REQUIREMENTS Jet-A Jet-A-1 Jet fuel type Gravity, API, max Gravity, API, min ASTM distillation, F.:

It has been estimated that the demand for standard jet fuel of the foregoing type, by the airline industry in the United States, will increase to about 1.12 million barrels per day in 1975. The potential snpply, estimated at about 2.2 million barrels per day in 1975, of petroleum stocks within the boiling range of about 315 F. to about 500 F., appears to be more than ample to supply ths demand. It must be recognized, however, that this particular boiling range fracton also contrbutes in part in supplying other fuels including military JP-4 and JP-5, diesel fuels, heating oils and kerosene, gasoline and petrochemcal feed stocks. It must be borne in mind that, prior to 1975, the advent of jumbo iets and supersonic transports wil1 serve only to increase the demand for jet fuel kerosenes by virtue of significantly increased fuel consumption necessitated by size and speed.

As hereinbefore set forth, it is contemplated that the requirements of the properties of a jet fuel suitable for use in supersonic transports will be more stringent. Some of the proposed properties are presented in the following abbreviated Table II:

Table II: Propos ed supersonic jetfuel. property The source of the requirements stated in the foregoing Table II is D. H. Stormont, Oil & Gas Journal, pp. 39- 42 (May 15, 1967 While it appears certain that the overall eflect of the jumbo jets and supersonc jet transports will be to increase the demand for greater quantities of jet fuels, is is not possible to project the exact quantity in terms of millons of barrels per day. As the supersonic jet transports displace the standard jet in use today, the demand for standard jet fuel will certainly decrease, althogh the combned demand for both sonic and supersonic jet fuels will certainly increase. The process encornpassed by our invention recognizes that there will be a dramatic need for both the supersonic and sonic jet fuels, and atfords the simultaneous production of both inan economical and relatively facile manner.

OBJECTS AND EMBODIMENTS Another object of the present invention aflords the;

simultaneous production of sonic and supersonic jet fuels. Ai1other object is to provide a semi-series flow, mul-- tiple-reactionzone process for the production of sonic and supersonic jet fuels.

Therefore, in one of its embodiments, the present invention is drected towrd a process for producng jet fuel kerosene fractions from a sulfurous, aromatic, higher boiling charge stockwhich comprises the steps of (a) reacting said charge stock With hydrogen in a first catalytic reaction zone at a maximum catalyst bed temperature of about 850 F. and a pressure greater than about 1000 p.s.i.g., said temperature and pressure being selected to convert sulfurous compounds into hydrogen Sulfide and hydrocarbons; (b) separating the reslting first reaction zone eflluent in a first separation zone, at substantially the same pressure and a lower temperature, to provide a first vaporous phase and a first liquid phase; (c) separating said first vapor phase in a second separation-zone, at substantially the same pressure and at a temperature of from about 60 F. to about 140 F., to provide a hydroge'n-rich second vaporous phase and a second liquid phase; (d) separating said second liquid phase in a third separation zone, at conditons of temperature and pressure to provide a third liquid phase containing hydrocarbons boiling above about 550 F. and to recover a standard jet fuel kersene fractibn; (e) reacting said third liquid phase and at least a portion of said first liquid phase with hydrogen in a second catalytic reaction zone at a maximum catalyst bed temperature of about 750 F. and at a pressure greater than about 1000 p.s.i.g., said temperature and pressure selected to saturate aromatic hydrocarbons; (f) separating the resultng reaction zone effluent in a fourth separation zone, at substantially the same pressureand at a temperature of from 60 F. to about F. to provide a hydrogenrich third vaporous phase and a fourth liquid phase; and (g) separating said fourth liquid phase in a fifth separating zone, at conditions of temperature and pressure selected to provide a fifth liquid phase containing hydro. carbons boilng above about 550 F. and to recover a supersonic jet fuel fraction.

Other embodirnents of our invention are directed toward preferred processing techniques, operating conditions and various catalytic composites for utilization in the multiple reaction zones. For example, one technique involves recycling at least a portion of the fifth liquid phase containng hydrocarbons boiling above about 550 F. to the second catalytic reaction zone. In another embodiment, the first reaction zone effluent is separated in the hot separator at temperature of from about 550 F. to about 750 F. The preferred catalytic composite disposed within said second catalytic reaction zone comprises a Group VIII noble metal component, and preferably a platnum and/or palladium component. These as well as other objects and embodiments of our invention will be evident from the following, more detailed description thereof.

SUMMARY OF INVENTION As hereinbefore set forth, the primary purpose of our invention is to provide a process which aifords the simultaneous production of both sonic and supersonic jet fuels. In etect, this purpose is accomplished through the utilization of a two reaction zone system, utilizing catalytic composites of varying characteristics. Briefly, in the first reaction zone, the catalytic composite and operatng con ditions are selected for complete desulfurization of the Charge stock, whle smultaneously converting heavier hydrocarbons into a 300 F./550 F. standard (sonic) jet fuel and gasoline boiling range hydrocarbons. The product efliuent from the first reaction zone is separated in such a manner to recover the standard jet fuel as a product stream, the heavier portion serving as the charge, in semi-series flow, to the second reaction zone. The primary function of the second reaction zone is to saturate aromaties whle simultaneously cracking the heavy gas oil components into kerosene boiling range hydrocarbons suitable for use as supersonic jet fuelS.

Before further summarizing our invention, it is believed that several definitions are necessary in order that a clear understanding be available. The present specification, as well as the appended claims, the use of the term pressure substantially the same as is intended to connote that the pressure imposed upon a given vessel, or section of the system, is the same as the pressure imposed uponthe vessel mmediately upstrearn therefrom, allowing only for the pressure drop naturally occurring as a result of the flow of fluids through the system. Similarly, the term temperature substantially the same as is intended to indicate that the temperature of a givenstream entering a particular vessel is substantially the same as the temperature of the stream as it emanated from the vessel mmediately upstrearh therefrom. Taken into consideration is, of course, the temperature drop due to heat loss, and to that from the conversion of sensible to latent heat due to vaporization. Where utilized herein, the term semi-series flow alludes to the fact that the product efluent from the first catalytic reaction zone is passed, at substantially the same pressure, into the second catalytic reaction zone. In many instances, this charge to the second reaction zone need not be heated, but can be introduced at subst'antially the same temperature it has as it emanates from the first separation zone.

The present invention involves the utilization of a first catalytic reaction zone having disposed therein a catalyst comprising a metallic component from Group VI-B and the Iron-Group of the Periodic Table, the primary purpose of which is to elect substantially complete desulfuriza tion of the hydrocarbonaceous feed stock at comparatively mild severities. The catalytic composite, utilized in the second reaction zone for the purpose of saturating aromatic hydrocarbons and hydrocrackihg gas oil boilng range material into kerosene fraction components, comprises a Group VIII noble metal component. Intermediate the two zones is a hot separator, functioning at substantially the same pressure as the first reaction zone and at a temperature in the range of trom about 500 F. to about 800 F., and preferably trom about 550 F. to about 750 F. The liquid phase from the hot separator, at substantially the same pressure, is introduced into the second catalytic reaction zone, often without substantal change in temperature.

The catalytic composites utilizecl in the present process comprise metallic components selected from the metals of the Group VI-B and VIII of the Periodic Table, and compounds thereof. Thus, in accordance with the Periodic Ta'b1e of the Elements, E. H. Sargent & Co., 1964, suitable metallic components are those selected from the group consisting of chromimum, molybdenum, tungsten, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium and platinum. While neither the precisc composition, nor the method of manufacturing the catalyst is considered essential to our invention, certain aspects are preferred. For example, since the charge stocks to the present process are gas oil fractions, a considerable portion of which boils above the kerosene boilng rangei.e. above about 550 F.it is preferred that the components of the cataiyst possess the propensity for eifecting a certain degree of hydrocracking While simultaneously producing a substantially sulfur-free normally liquid hydrocarbon product. Suitable catalytic composites, for use in electing the desulfurization reactions in the first reaction zone, generally comprise trom about 4.0% to about 40.0% by weight of a Group VI-B metallic component, and from about 1.0% to about 6.0% by weight of an IronGroup metallic component. It is underst ood that these concentrations, as well as those hereinafter set forth, are computed on the basis of the elemental metals, regardless of the precise state in which they exist within the catalytic composite. These catalytically active components are generally composited with a suitable siliceous refractory norganic oxide carrier material, the quantity of silica generally determining the degree of hydrocracking activity. Suitable refractory norganic oxides include alumina, zrconia, magnesa, titania, thoria, boria, hafma, etc. Another group of suitable carrier materials are those having combined therewith from about 5.0% te about 35.0% by weight of boron phosphate. In general, the silica to alumina weight ratio will be within the range of trom about /90 to about 80/20.

With respect to the second reaction Zone, the catalytic composite employed for effecting aromatic saturation as well as hydrocracking, comprises metallic components from Group VIII in amounts within the range of trom about 0.01% to about 5.0% by weght. Since the process encompassed by the present inveution utilizes a hot separator, as the first separation zone, to provide the liquid phase subsequently utilized as the charge to the second catalytic reaction zone, it must be recognized that this liquid phase =will contain at least a minor portion of dissolved hydrogen sulfide resulting from the conversion of sulfurous compounds in the first reaction zone. These catalytic components are also combined with one or more of the foregoing refractory norganic oxides, whch, in some instances, may be crystalline aluminosilicates, or zeolitic material. These catalytic components, various compositions thereof in the inethods of manufacture are well-described within the prior art, and addtional discussion herein is not believed to be necessary.

In practcing the present invention, the charge stock, for example, a vacuum gas oil derived from a sour Wyoming crude oil, having a sulfur concentration of about 2.42% by weight, an initial boilng point of 540 F. and an end boilng point of 1015 F., containing about 50.5% by weight of aromatic hydrocarbons, is admixed with recycle hydrogen in an amount of about 3,000 to about 20,000 standard cubic feet per barrel. Following suitable heat-exchange with various hot product efiluent streams, the hydrocarbon/hydrogen mixture is heated to a temperature level such that the catalyst bed temperature is controlled within the range of from about 600 to a maximum of 850 F. The catalyst bed inlet temperature is regulated to control the outlet temperature at a maximum level of 850" F., and preferably not higher than 800 F. Since the principal reactions are exothermic in nature, a temperature rise will be experienced as the charge stock passes through the catalyst bed. A particularly preferred technique limits the temperature increase in the first catalytic reaction zone te about F. and the use of conventional quench streams, at one or more intermediate loci of the reaction zone, is contemplated for this purpose. T he reaction zone contains, for example, a catalyst of 1.8% by Weight of nickel and 16.0% by weight of molybdenum combined with a carrier material of 63.0% by weight of alumina and 37.0% by weight of silica. The reaction zone is maintained under an imposed pressure of from about 1000 to about 4000 p.s.i.g., and the liquid hourly space velocity (defined as volumes of liquid hydrocarbon charge per hour per volume of catalyst) is in the range of from about 0.4 to about 3.5.

The total product eflluent, without substantal change in pressure, although sometimes at a lower temperature of trom about 550 F. to about 750 F., is introduced into a hot separator. A vaporous phase, comprising hydrogen, hydrogen sulfide, ammonia, normally gaseous hydrocarbons, butanes, pentanes and heavier hydrocarbons boiling below about 550 |F., is wthdrawn from the hot separator and introduced, at a temperature in the range of trom 60 F. to about F. into a cold separator. The temperature of the stream entering the hot separator is controlled at a level whch insures that substantially all of the standard jet fuel components, for example, boilng trom about 300" F. to about 550 F. are carried over in the vapor phase, While substantially all of the hydrocarbonaceous material boilng above a temperature of about 550 R, is wthdrawn from the hot separator as a liquid phase. Condensed, normally liquid hydrocarbons are removed from the cold separator, and subjected to a product recovery systemi.e. a distillation colurnnin order to recover the desired jet fuel fraction.

In one embodiment, dependent upon the charge stock, a portion of the liquid phase wthdrawn from the hot separator is recycled to combine with the fresh gas oil charge stock to the first reaction zone. This particular technique also affords a certain degree of flexibility with respect to the quantity of standard jet fuel, since the heavier components are once again subjected to an environment conducive in part to hydrocracking. Suitable combined feed ratios, defined as volumes of total liquid charge per volume of fresh hydrocarbon charge, are within the range of trom about 1.1 to about 3.5. That portion of the liquid phase not being recycled serves as part of the total liquid charge to the second catalytic reaction zone. As hereinabove set forth, the liquid phase from the cold separator is subjected to a product recovery system in order to recover a standard jet fuel fraction. A bottoms fraction, containing those hydrocarbons boilng above the desired end boilng point of the standard jet fuel fraction is combined with the liquid phase from the hot separator and serves as the charge to the second catalytic reaction zone.

The catalyst disposed in the second reaction zone is a composite of about 0.4% by weight of platinum, calculated as the element, combined with a refractory inorganic oxide of 75.0% by weight of silica and 25.0% by weight of alumina. The reaction zone is maintained at a pressure above about 1000 p.s.i:g., having an upper limit of about 3000 p.s.i.g. The hydrogen circulation rate is at least about 3000 standard cubic feet per barrel, with an upper limit of about 15,000 standard cubic feet per barrel. The liqud hourly space velocity, previously defined is, within the range of from about 0.5 to about 4.0. It is particularly preferred to mantain the maximum catalyst bed temperature at a level not exceeding 750 F. Therefore, in some situations, it may be necessary to utlize the normally liqud portion of the first reaction zone product efiluent as a heat-exchange medium in order to decrease its temperature for the purpose of controlling the maximum temperature of the catalyst disposed within the second reaction zone. In many applications of the present invention, the inlet temperature of the catalyst bed within the second catalytic reaction zone will be in the range of from about 550 to about 700 F. As previously stated in regard to the first catalytic reaction zone, a temperature rise is experienced as the charge stock passes through thecatalyst bed. It is preferred, with respect to the second catalytic reaction zone, to limit such temperature rise to about 50 F., and the use of conventional quench streams at one or more intermediate loci of the reaction zone, is again contemplated for this purpose. The total product effluent from the second catalytic reaction zone is introduced into a second cold separator, at substantially the Same pressure and at a temperature in the range of from about 60 F. to about 140 F. The principally vaporous phase, from the cold separator to which the second catalytic zone eflluent is passed, is substantially clean with respect to hydrogen sulfide. In many instances, however, the operation of the overall process is facilitated (particularly with respect to commercially-scaled units), when the vapor phases from both cold separators are combined and introduced in admixture into a hydrogen sulfide removal system. After being raised to the desired operating pressure, a substantially hydrogen sulfide-free, hydrogen-rich vapor phase is utilized as recycle to both the first and second reaction zones.

The normally liqud hydrocarbon portion emanating from the second catalytic reaction zone, is recovered from the cold separator and introduced into product separatiorr means distinctly separate from the product recovery system utilized with respect to the normally liqud effluent from the first reaction zone. As hereinbefore indicated, the property requrements of sonc, or standard jet fuels dier considerably from those imposed upon supersonic jet fuels. Therefore, the present process, designed for the simultaneous production of the two types of jet fuels, utilizes separate product recovery systems to insure that the two product streams are not mixed. Exemplary of the component separation etfected with respect to the normally liqud product efliuent from the second reaction zone is a normally gaseous stream comprising butanes, lighter hydrocarbons and other gaseous components; a pentane/ hexane fraction which may be utilized as a motor fuel blending component; a heptane to 375 F. motor fuel fraction which may be utilized in combinaton with other similarly constitutcd refinery streams as the charge to a catalytic reforming system; the desired supersonic jet fuel kerosene, for exarnple having a boiling range from 375 F. to 530 F.; and, a bottom stream containing the hydro carbonaceous material boiling at a temperature above the desired end point of the supersonic jet fuel. The latter steam is conveniently recycled to combine with the charge to the second catalytic reaction zone, generally providing a combined feed ratio in the range of from about 1.25 to about 4.5.

DESCRIPTION OF DRAWING The process encompassed by our invention is more clearly understood by reference to the accompanying drawing which illustrates one embodiment thereof. In the drawing, only those vessels and process lines required for a complete understanding of the embodiment have been included. Miscellaneous appurtenances, ncluding valves, press-ure-feducing valves, controls, instruments, pumps, compressors, heat-cxchangers, start-up lines and heat-re covery circuits, etc., have either been reduced in number or completely eliminated. The use of this kind of conventional hardware is well within the purvew of those skilled in the techniques of petroleum refining processing. It is further understood that the drawing is presented for the sole purpose of illustration, and is not intended to be limited to the particular charge stock, quantites, rates, operating conditons, etc., employed by way of explanation. With reference now to the drawing, the charge stock, for example, the vacuum gas oil derived from a sour Wyoming crude oil, the property inspections of which are presented in the followng Table 111, is introduced into the process by way of line 1.

Table III: Vacuum gas oil charge properties Gravity, API 21.2 ASTM distillation, F.: IBP 590 90.0% 955 95.0% 985 End point 1015 Sulfur, wt. percent 2.42 Nitrogen, wt. pp. 1300 Bromine number 2.9 ASTM elution, wt. percent:

Aromatics 50.5 Non-aromatics 49.5 Aniline point, F. 180 Pom point, F. +70

The charge stock continues through line 1, being adrnixed with a recycled hydrogen stream from Iine 2, in an amount of about 6,000 standard cubic feet per barrel. The charge stock rate is about 9,700 barrels per day, and it is intended that this charge stock be convcrted into jet fuels in a yield of about 50.0% by volume. With respect to the indivdual quantites of sonic and supersonic jet fuels, the intended division is approximately 50.0% of each. In the present illustration, the charge stock/hydrogen mixture, following heat-exchange with relatively hot efiiuent streams, continues through line 1 into heater 4. With this particular charge stock, and the desired dstribution of the jet fuel components, the operation does not call for a liqud recycle to be admixed with the charge stock in line 1. When this technique is deemed advisable, the recycled materal is admixed with the charge stock by way of line 3.

Heater 4 raises the temperature of the incoming hydrogen/charge stock stream to a level of about 675 F., as measured at the inlet to the catalyst bed disposed within reactor 6. The thus-heated mixture is introduced downflow by way of line 5, and is withdrawn from reactor 6 by way of line 7 at a temperature of about 775 F. The catalyst disposed within reactor 6 is principally a desulfurization catalyst having some hydrocracking activity, and comprises 1.8% by weight of nickel and 16.0% by weight of molybdenum, computed as the elemental metals, combined with a carrier material of 63.0% by weight of alumina and 37.0% by weight of silica. The charge stock,

at the pressure of about 1500 p.s.i.g., passes through the catalytic composite at a liqud hourly space velocity of about 0.60.

Component analyses of the product efiiuent withdrawn from reactor 6 by way of line 7 are presented in the following Table IV and reflect a hydrogen consumption (exclusive of solution loss) of about 1217 standard cubic feet per barrel. Thus, the values indicated in the following Table IV take into account 1.99% by weight of hydrogen, based upon the fresh charge stock.

TABLE IV.REACTOR 6 COMPONENT STREAM ANALYSES The hot reaction zone effluent in line 7 is utilized as a heat-exchange medium to reduce its temperature to a level of about 600 F. and continues through line 7 into hot separator 8. A first principally vaporous phase, containing substantially al] of the material boiling below a temperature of about 55 F., and substantially free from hydrocarbonaceous material boiling above 550 R, is removed by way of line 9, cooled to a temperature of about 100 F., and introduced into cold separator 10. The second principally vaporous phase is withdrawn frorn cold separator 10, by way of compressive means not illustrated in the drawing, and continues through line 2 to be admixed With the charge stock in line 1. Make-up hydrogen, to compensate for that consumed within the process, may be introduced fiom any suitable external source, at any suitable location in the process system. As hereinbefore set forth, the vaporous phase from line 2 may be treated, when necessary, for the removal of gaseons constituents other than hydrogen in order that the hydrogen concentration be about at least 80.0 m01 percent. Such treating facilities are well known in the prior art, and, therefore, are not indicated in the drawing.

A first principally liqud phase is withdrawn from hot separator 8 by way of line 18, and serves as a portion of the charge ultimately introduced into reactor 14. The normally liqud hydrocarbon streatn from cold separator 10 is withdrawn by way of line 11 and introduced into fractionator 12. Fractionator 12 functions at conditions of temperature and pressure which provides the standard jet fuel product stream, having an initial boiling point of 300 F. and an end boiling point of 550 F., to be withdrawn by way of line 17. An overhead stream comprising butanes, lighter normally gaseous hydrocarbons and other gaseous material is withdrawn by way of line 15, and may be further separated to recover particularly desred components. A pentane to 300 F. gasoline raction is removed from fractionator 12 by way of line 16, and may be utilized, at least in part, in a pool as the charge to a catalytic reformng unit. Hydrocarbonaceous material boiling above the desired end point of the standard jet fuel fracton, 550 F. is withdrawn by way of line 13, and is admixed With the hot separator liqud phase in line 18.

With respect -to the present illustration, the mixture of the material in line 13 and line 18 constitutes the fresh feed to reactor 14, in an amount of: about 5,140 barrels per day. This fresh feed is adrnixed With a recycle stream comprising hydrocarbonaceous material boiling above a temperature of about 530 R, in line 23, the source of which is hereinafter set forth. The quantity of liqud recycle is about 3,084 barrels per day, to provide a com bined liqud feed ratio to reactor 14 of about 1.6. The mixture continues through line 13, is admixed With 8,000 standard cubic feet per barrel of hydrogen from line 23, and is introduced by way of line 13 into reactor 14 at a pressure of about 1,500 p.s.i.g. and a catalyst bed in1et temperature of about 575 C. The catalyst disposed Within reactor 14 is the comp0site of about 0.4% by weight of platium, calculated as the elemental metal, combined With a carrier material of 75.0% by weight of silica and 25.0% by weight of alumina, and is employed in an amount such that the liqud hourly space velocity, based upon fresh feed exclusive of recyc1e, is 1.00.

The reactor product efiiuent is withdrawn by way of line 19, at a temperature of about 625 R, is cooled to a temperature of about F., and continues through line 19 to cold separtor 20. A third principally vaporous phase is withdrawn from cold separator 20 by way of line 23, the recycle therethrough, by compressive means not illustrated in the drawing, to combine With the fresh feed in line 13. A principally liqud phase, consisting prmarily of normally liqud hydrocarbons, is withdrawn from cold separator 20 by way of line 21, and after suitable heat-exchange With hot product effluent streams, is introduced therethrough into fractionator 22.

Fractionator 22 is maintained under conditions of temperature and pressure which insures the recovery of the supersonic jet fuel, having an initial boiling point of 375 F. and an end boiling point of about 530 F., by way of line 27. Hydrocarbonaceous material boiling above a temp6rature of about 530 F. is withdrawn from fractionator 22 by way of line 28, and recycled therethrough to combine With the fresh feed in line 13, thereby providing a combned liqud feed ratio of about 1.6. Butanes, lghter normally gaseous hydrocarbons and other gaseous material is withdrawn from fractionator 22 by way of line 24. A pentane/hexane component fraction is removed by way of line 25' and a heavy naphtha, gasoline boiling range material is withdrawn by way of line 26. The latter is indicated as comprisng heptane and hydrocarbons boiling up -to the initia1 boiling point of the supersonic jet fuel, 375 F.

Component stream analyses of the product efiiuent from reactor 14 are presented in the following Table V.

1 Based upon fresh gas 0i1 charge stock. 2 Recycled to reactor 14.

The values indicated in the foregoing Table V reflect an additional hydrogen consumption of 753 standard cubic feet per barrel, or about 1.23% by weight, based upon the fresh gas oil charge stock in line 1. For convenience, the overall product distribution and yields, based upon the gas oil charge rate of 9,700 barrels per day, is presented in the following Table VI.

TABLE VI.OVERALL PRODUCT YIELD AND DIST RIB UTION Wt. Vol.

Component percent percent Bbllday Ammonia 0. 16 Hydrogen sulfide 2. 57 Methano... 0. 30 Ethane.--. 0. 38 Propane 1. 95 Butanes.-. 7. 56 12. 29 1, 190 Pentanes. 7. 61 11. 27 1, 090 Hexanes 6. 91 9. 26 898 Hepta.nes37 F 33. 56 41. 44 4, 012 300 F-550" 22. 99 26. 20 2, 540 375 F.530 F-- 19. 23 22. 07 2, 140

Totals 103. 22 122. 53 11, 870

l Reflect total hydrogen eonsumption of 1,970 s.e.f.lbbl.

by volume of the 1,090 barrels per day of pentanes are isopentanes. A mixture of the pentane and hexane product has a gravty of 84.4" API, a clear research octane number of 84 (raised to 98 With the additon of 3 m1. TEL), and constitute 86.0% by volume paraflinic hydro carbons and 14.0% by volume of naphthenes. The mixture of the two heavy naphthas produces in the first and second reaction zones, totaling 4,012 barrels per day, has a gravty of 57.0 API, and a clear octane rating of 56 (elevated to 76 upon the addton of 3 ml. TEL); and consisted of about 47.0 vol. percent parafiins, 52.0 vol. percent naphthenes and 1.0 vol. percent aromatics, thereby consttutng an excellent charge to a catalytc reforming unit.

Pertinent analytical data, With respect to the two jet fuel fractons is presented in the following Table VII:

TABLE VIL-JET FUEL IROPERTIES Jet fuel type Standard Supersonie Gravity, API 42. 5 43. 7 Aromatics, vol percent... 16. 0 1. 0 Anilne pont, F 141 161 Freeze point, I Flash pont, F- 155 Smoke point, F- 23 35 Sulfur, wt. p.p.m.. 3 1

(a) reacting said charge stock With hydrogen in a first catalytic reaction zone at a maximum catalyst bed temperature below about 850 F. and a pressure selected to convert sulfurous compounds to hydrogen sulfide and hydrocarbons;

(b) separating the resultng first reaction zone efiiuent in a first separaton zone, at substantally the same pressure and alower temperature, to provide a first vaporous phase and a first lqud phase;

(c) separatng the first vapor phase in a second separaton zone, at substantially the same pressure and at a temperature of from 60 F. to about F., to provide a hydrogen-rich second vaporous phase and a second lqud phase;

(cl) separating said second lqud phase in a third separaton zone, at conditions of temperature and pressure to provide a third lqud phase containing hydrocarbons boiling above about 550 F. and to recover a standard jet fuel kerosene fraction;

(e), reacting said thirdliquid phase and at least an aliquot portion of said first lqud phase With hydrogen in a second catalytic reaction zone at a maximum catalyst bed temperature below about 750 F. and at a pressure greater than about 1000 p.s..g., said temperature and pressure selected to saturate aromatc hydrocarbons;

(f) separating the resulting second reaction zone effluent in a fourth separaton zone, at substantially the same pressure and at a temperature of from 60 F. to about 140 F. to provide a.hydrogen-rich third vaporous phase and a fourth lqud phase; and,

(g) separating said fourth lqud phase, in a fifth separation zone, at conditions of temperature and pressure selected to provide a fifth lqud phase containng hydrocarbons boiling above about 550 F. and to recover a supersonic jet fuel fraction.

2. The process of claim 1 further characterized in that at least a portion of said fifth lqud phase is recycled to said second catalytic reaction zone.

3. The process of claim 1 further characterized in that the first reaction zone efiluent is separated in said first separaton zone at a temperature of from about 500 F. to about 750" F.

4. The process of claim 1 further characterized in that at least a portion of said first lqud phase is recycled t'o said first catalytic reaction zone.

5. The process of claim 1 further characterzed in that the catalytic composite disposed in said second catalytc reaction zone compriseS a Group VIII noble metal com ponent.

6. The process of claim 1 further characterized in that the catalytic composite disposed With said first catalytc reaction zone comprises a metallic component from the metals of Groups VI-B and the Irongroup.

References Cited UNITED STATES PATENTS 5/1964 Kelley et al. 20860 DELBERT E. GANTZ, Pr.imary Examiner A. RIMENS, Assstant Examiner U.S. C1. X.R.

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