US3222274A

US3222274A - Process for producing high energy jet fuels

Info

Publication number: US3222274A
Application number: US250202A
Authority: US
Inventors: Paul R Carl
Original assignee: Socony Mobil Oil Co Inc
Current assignee: ExxonMobil Oil Corp
Priority date: 1963-01-02
Filing date: 1963-01-02
Publication date: 1965-12-07
Anticipated expiration: 1982-12-07

Description

Dec. 7, 1965 P. R CARL PROCESS FOR PRODUCING HIGH ENERGY JET FUELS Filed Jan. 2, 1963 HIGH SULFUR NAPH 7' HA ll 0 3 Hydrogenaler [2/ Reformer LOW SULFUR NAPHIHA H CONTAINING 28 JET FUEL 0R HIGH OCT/WE NAPHFHA P-l6 GASOL W [5 Prafrbarer 2/ V26 7 2 39 27) I H1 CONTAINING l7 6.4.5

- --Nvw k Reformer HIGH OCT/l NE GASOLINE IN VEN TOR. Pau/ R,

Afro/nay United States Patent 3,222,274 PROCESS FOR PRODUCING HIGH ENERGY JET FUELS Paul R. Carl, Woodbury, N.J., assignor to Socony Mobil Oil Company, Inc., a corporation of New York Filed Jan. 2, 1963, Ser. No. 250,202 7 Claims. (Cl. 208143) The present application is a continuation-in-part of my copending application, Serial No. 586, filed January 5, 1960 now abandoned, entitled Process for Producing High Energy Jet Fuel.

This invention relates to a process for producing high energy jet fuels by hydrogenation of selected hydrocarbon fractions over specified catalysts.

The demand for jet fuels is expected to increase very substantially in the near future. Much of this increase will, of course, be due to increased use of jet aircraft by commercial airlines. There is, therefore, considerable current interest in techniques for producing this fuel and means for improving its quality.

Jet engine manufacturers presently are making turbines which tax the temperature resistance of their metal parts with present day fuels. These engines, and even more extreme ones planned, will require improved fuels which do not burn so hot as to injure the metal parts of the engine. It has been determined that the tendency of jet fuels toward high temperature burning is directly related to the tendency of the fuels to smoke.

There has recently been developed a new test which seems to more accurately rate the tendency of jet fuels to smoke. Details of the test are given in A.S.T.M. Standards on Petroleum Products and Lubricants, appendix VIII, October 1959, page 1157, entitled Proposed Method of Test for Luminometer Numbers of Aviation Turbine Fuels. Briefly, this test involves comparison of the fuel in question with two reference fuels, isooctane and tetralin in an instrument called a Luminometer. This results in a rating called the luminometer number (L.N.). The higher the luminometer number, the better the jet fuel. Present jet fuels have ratings of about 45 to 60 L.N. It is hoped, however, that in the near future fuels of at least 100 LN. will be available.

The prior art has recognized that for a given number of carbon atoms, saturated compounds give the highest L.N., while aromatics give the lowest. It has, therefore, been suggested that a suitable boiling range material be subjected to extraction or adsorption to remove the aromatics and produce a high L.N. fuel. Both of these processes, however, are quite expensive and completely new facilities must be installed in most oil refineries in order to practice them.

Another desirable feature for a jet fuel that is to be used in commercial airlines is that it have a high heat content per unit weight. This is because most commercial aircraft are weight limited. On the other hand, military aircraft usually require a high heat content per unit volume, since such aircraft are usually limited as to space rather than weight. Improvement of the energy content per unit weight would mean an increase in the flying range of present day aircraft with a given load of fuel.

"ice

A process is herein disclosed in which jet fuels of high heat content per unit weight, at least 18,900 B.t.u. per pound and of high luminosity number, at least 130, are produced by a technique which can be practiced in most oil refineries, usually without substantial additions to the equipment already there.

A major object of this invention is to provide a process for the production of high energy jet fuel.

Another object of this invention is to provide a process in which high energy jet fuel and high octane rating naphtha are simultaneously produced.

Another object of this invention is to produce a jet fuel which will increase the flying range of present day commercial aircraft.

Another object of this invention is to produce a jet fuel less prone to damage metal parts of the jet engine than present day fuels.

These and other objects of this invention will become apparent from the following discussion.

In this invention a naphtha which boils within the range of about F. to about 400 F. and meets the following specifications: at least 60 volume percent paraffins plus noncyclic olefins, no more than 38 volume percent naphthenes, and 2 to 40 volume percent aromatics is hydrogenated by passing the naphtha over a catalyst which has a hydrogenation component selected from the group consisting of the metals having atomic numbers 44 to 46 inclusive and 76 to 78 inclusive, nickel-tungsten sulfide, tungsten disulfide and nickel-molybdenum sulfide. The aroma-tics in the naphtha are hydrogenated to produce thereby a jet fuel having a luminosity number of at least 130. In a more specific application the catalyst used is a platinum-containing catalyst capable of also being used to reform naphthas, and the temperature in the hydrogenation Zone is periodically increased to a reforming temperature to produce high octane naphtha for a period and then reduced to produce jet fuel for another period. An important advantage from such an embodiment, using the same catalyst for both reforming and hydrogenation, is that any sulfur that accumulates in the catalyst during the hydrogenation step is quickly removed when the process is changed I to the higher reforming temperature whereby the catalyst reverts to highly suitable conditions for subsequent hydrogenation. In another specific application two separate units are employed, one continuously being used to reform naphtha which does not necessarily meet the foregoing specifications, while the other is continuously or periodically used to produce jet fuel, and the hydrogen needed in the second unit is produced in the first.

This invention will be best understood by referring to the attached drawing. This drawing illustrates, in highly diagrammatic form, the application of the process of this invention to an oil refinery in which there are available two separate units in which reforming of naphthas may be practiced. This refinery would also have available a variety of different naphthas, at least one of which has at least 60 volume percent paraffins plus noncyclic olefins, no more than 38 volume percent naphthenes, and 2 to 40 volume percent aromatics. This naphtha, if its sulfur content is above about 0.003 weight percent, is desirably supplied first to a pretreating unit through line 11, together with a hydrogen-containing gas admitted through line 12. The pretreater would be operated in conventional manner to reduce the sulfur content of the naphtha to below about 0.003 weight percent. Thus, the unit might employ conventional cobalt molybdate catalyst and operate at a ternperature within the range 600 F. to 700 F., under a hydrogen pressure of 200 p.s.i.g. to 500 p.s.i.g., with a hydrogen circulation rate of 300 s.c.f. per barrel of charge to 1000 s.c.f. per barrel of charge and a liquid hourly space velocity within the range 1 to 10 volumes of charge (as 60 F. liquid) per volume of catalyst per hour. The pretreater effluent is passed to separator 41 by means of line 13. In the separator hydrogen which will be diluted with substantial amounts of hydrogen sulfide is removed through 43. This hydrogen may be purified in conventional manner and returned to the system. Naphtha is removed from separator 41 through line 42. Other methods of reducing the sulfur content may be used, such as conventional acid treatment of the high sulfur naphtha.

If the sulfur content of the naphtha is initially below about 0.003 weight percent, the pretreater or other sulfur reduction technique need not be used and the naphtha may be supplied through line 14.

Another naphtha which may or may not meet the foregoing specifications is supplied through line 15, together with hydrogen through line 16, to pretreater 17. This pretreater may be operated in the same manner as pretreater 10.

The pretreated naphtha is passed by means of line 37 to separation zone 38 in which the hydrogen that has not been consumed in pretreater 17 is separated from the naphtha and removed through line 39. Since this hydrogen will usually be diluted with a substantial amount of hydrogen sulfide, it should be passed to a purification step (not shown) before being used again in the system. The naphtha passes from separator 38 through line 40, is joined by a suitable quantity of hydrogen from line 27 and both hydrogen and naphtha are heated to reforming reaction temperature, usually within the range about 800 F. to 1000 F in heater 19. The naphtha-hydrogen mixture is then passed into reformer 20 through line 21.

Reformer 20 will employ a catalyst suitable to reform the naphtha. Such catalysts are well known in the art and will frequently contain platinum metal as a hydrogenation-dehydrogenation component. One suitable catalyst is described in United States Patent 2,838,444. This catalyst contains about 0.1 to about 1 percent platinum in finely dispersed form on an alumina base. The reaction conditions Within the reformer will customarily include a temperature within the range 800 F. to 1000 F., a hydrogen pressure within the range 100 p.s.i.g. to 500 p.s.i.g., a hydrogen circulation rate within the range 5000 s.c.f. per barrel of charge to 10,000 s.c.f. per barrel of charge and a liquid hourly space velocity within the range 0.5 to 2 molumes per volume per hour. The reformed product exits through line 23 to a separator 24. In the separator the hydrogen is separated from the hydrocarbons which can be liquefied at normal temperatures. These hydrocarbons form a high octane product which is removed through line 25. The hydrogen is taken off the top of separator 24 through line 26. A portion of this hydrogen is returned to reformer 20 through

lines

27 and 21 to maintain the hydrogen atmosphere therein. Another portion passes through

lines

28 and 16 to supply the pretreater 17. Still more of this hydrogen may be used in pretreater 10, by means of

lines

28 and 12 and, as explained below, another part is supplied to reactor 29 by means of lines 36 and 31. Since the sulfur content may have a material effect on the hydrogenation reaction practiced in reactor 29, it may be desirable to employ one of the conventional means for hydrogen sulfide removal from this hydrogen stream.

The high energy jet fuel is produced in reactor 29. To accomplish this the reactor should be filled with one of a specified group of catalysts which have been found effective for saturating aromatics in charge stocks of the type here used to a sufficient extent, at modest temperatures and pressures, to produce the high energy jet fuel. Catalyst which have as a hydrogenation component one or more of the noble metals of the platinum-palladium series, that is, the metals having atomic numbers 44 to 46, inclusive, and 76 to 78, inclusive, may be used. Particularly effective in this group is platinum. Other suitable hydrogenation components include nickel-tungsten sulfide, tungsten disulfide and nickel-molybdenum sulfide. These hydrogenation components may be employed alone or they may be distributed over a base or carrier which will usually be one or more refractory oxides, such as alumina, silica-alumina or silica-zirconia. The catalyst may also include a concentration of halide, e.g., fluoride, usually within the range about 0.05 to 8 percent by weight of the catalyst. Most of the aforementioned catalysts are available commercially. The preferred catalysts are those which are also capable of reforming. A particularly favorable catalyst of this type is the platinum on alumina catalyst described in United States Patent 2,838,444 and sold commercially as a reforming catalyst. This catalyst is composed of 0.1 to 1 percent by weight'of a platinum series metal, usually platinum. The metal is dispersed on an alumina base in a manner such that there are no crystals or crystallites of a size greater than 50 Angstrom units. The base is such that the finished catalyst has a surface area of about 350 to 550 square meters per gram. There may, of course, be other hydrogenation components, not enumerated above, which will be effective to produce high energy jet fuel from selected naphthas but which were not tested in this invention. On the other hand, it has been found that some hydrogenation catalysts are not suitable for use in this invention because they will not saturate aromatics under the mild reaction conditions which are necessary for satisfactory operation. Examples are the catalysts sold commercially which employ a mixture of cobalt and molybdenum oxides as bydrogenation component.

The specified charge stock suitably desulfurized in pretreater 10 or the charge stock which does not require desulfurization supplied through line 14 is joined by a suitable quantity of hydrogen from line 36 and the mixture is heated in a heater 30 to the reaction temperature which should fall within the range 300 F. to 750 F. and preferably 500 F. to 650 F. The heated charge stock then passes through line 31 into reactor 29. In the reactor a hydrogen pressure Within the range 50 to 500 p.s.i.g. and preferably to 500 p.s.i.g. should be maintained, a hydrogen circulation rate within the range 5000 s.c.f. per barrel of charge to 10,000 s.c.f. per barrel of charge and a liquid hourly space velocity within the range 0.1 to 10.0 vol./vol./hr.

Unsaturated materials, including aromatics, in the charge are hydrogenated in the hydrogenation zone and the product, together with hydrogen, is removed through passage 32. The hydrogen is separated from the higher boiling jet fuel material in separator 33 and high energy jet fuel, which will have a luminometer number of at least and preferably at least 135, is removed at line 34. Hydrogen is recycled to the reaction zone through line 35. Since hydrogenation is a hydrogen consuming reaction, the additional hydrogen needed is taken from the hydrogen produced in reformer 20 and supplied to the hydrogenation zone through

lines

26, 36, 42 and 31.

One feature of this invention is the inherent flexibility of the operation. Since the current demand for jet fuel is relatively low compared to many of the other products. of the oil refinery, it is unlikely that any unit of substantial size will have to be run full time in order to producesufficient jet fuel to satisfy this demand. In the combination of this invention, the desired quantity of jet fuel may be produced and at this point the temperature in reactor 29 m y be increased to a reforming temperature. The

product withdrawn at 34 will then be a second stream of high octane naphtha. Of course, to accomplish'this the catalyst will have to be one suitable for reforming.

This invention, in its broadest senSe,requires a naphtha charge stock boiling within the range of from about 150 F. to about 400 F. and comprising at least 60 volume percent parafiins and non-cyclic olefins, no more than 38 volume percent naphthenes, and 2 to 40 volume percent aromatics. Charge stocks which do not meet these specifications will not produce high luminometer rating jet fuels of at least 130 L.N. and preferably at least 135 L.N., nor will they produce jet fuels of high energy content per unit weight, i.e., at least 18,900 B.t.u. per gallon. It is preferred that the charge stock boil within the range 150 F. to 380 F. The lower limit of boiling range is usually controlled by the specification on vapor pressure.

Reaction conditions in the hydrogenation step will usually be as follows:

Aspreviously indicated, it is preferred that the hydrogenation be conducted in conjunction with the reforming of another naphtha fraction so that the hydrogen needed in the hydrogenation reaction is produced by the reforming. It is, of course, within the broad scope of this invention that hydrogen from another source be used.

Likewise, it is preferred that hte catalyst used in the hydrogenation reactor be a reforming catlyst so that, hydrogenation reactor to be a reforming catalyst so that, when sufficient jet fuel has been made, the operation may be shifted to reforming 'by simply raising the temperature.

It will be appreciated that rathcr'than the single reactor units shown in the drawing, each of

units

20 and 29 may be a plurality of reactors arranged in series or in parallel as desired. Also, the product recovery systems shown will, in a commercial unit, be much more elaborate so as to separate hydrogen and other light gases from the normally liquid products.

The sulfur content of the naphtha charged to the hydrogenation step should not be high, as sulfur interferes with the hydrogenation reaction. Therefore, only naphthas having sulfur contents below about 0.003 weight percent (30 parts per million) should be used. Of course, otherwise suitable naphthas may be made to conform to the requirement by appropriate treatment as indicated above.

The following Examples I to VI show the use of a variety of catalysts to produce jet fuels within the scope of this invention.

EXAMPLE I The charge stock (charge A) used was a pretreated West Texas bright naphtha and had the following properties:

6 Composition, percent vol.:

Parafiins 66.0 Naphthenes 27.4 Aromatics 5 .8

Other 0.8

This charge stock was hydrogenated in two separate runs, 10 and 11, using a commercial reforming catalyst comprising 0.6 weight percent platinum dispersed over an alumina base. This catalyst is the one described and claimed in United States Patent 2,838,444. The catalyst was in the form of A inch diameter pellets averaging about inch in length. The reaction conditions and properties of the products obtained are set out in Table I.

EXAMPLE II In this example, charge A, described in Example I, was hydrogenated over a catalyst comprising 0.4 weight percent platinum deposited on an inert alumina base. The catalyst size was about 8 to 16 mesh Tyler. This catalyst is described in United States Patent 2,885,352. Two runs were made, Runs 20 and 21, under reaction conditions set out in Table I to produce a product of the properties enumerated in Table 1.

EXAMPLE III Commercially available nickel-tungsten sulfide catalyst was employed to hydrogenate charge A of Example I. The approximate analysis of this catalyst was: 9 weight percent nickel, 60 weight percent tungsten and 27 weight percent sulfur. No base was used and the catalyst size was about 8 to 16 mesh Tyler. The reaction conditions and product inspections are reported in Table I as Run 30.

EXAMPLE IV Charge A of Example I was hydrogenated over a catalyst of nickel-molybdenum sulfide on a silica-alumina base. The base contained about 10 weight percent alumina. The finished catalyst comprised 6 weight percent nickel, 10 weight percent molybdenum, 6 Weight percent sulfur and 78 weight percent base. The operating conditions and product inspections are recorded as Run '40 in Table I.

EXAMPLE V A pretreated Kuwait naphtha (charge B) having the following properties was used:

Two runs, Runs 50 and 51, were made by passing this charge stock over the catalyst described in Example 1. Reaction conditions and product inspections are given in Table I.

EXAMPLE VI Charge B, described in Example V, was hydrogenated in Run 60 over a catalyst comprising nickel-tungsten sulfide on a silica-alumina base. The base contained approximately 10 weight percent alumina. The finished catalyst had a composition of about 4 weight percent nickel, 10 weight percent tungsten, 6 weight percent sulfur and 80 weight percent base. The catalyst was of a size within the range 8 to 16 mesh Tyler. Reaction conditions and product inspections are recorded in Table I.

Table I Run Charge A 10 11 I 20 i 21 30 40 Charge B 50 51 60 Reaction conditions:

Temperature, F- 500 550 500 550 600 600 500 550 550 Pressure, p.s.i.g- 300 450 300 450 600 600 150 450 600 Space velocity, vol./vol./

hr 6 4 6 4 2 1 0. 5 4 Hydrogen to oil, s.c.f./bbl. 5, 000 5, 000 5, 000 5, 000 5, 000 5, 000 10, 000 5,000 10, 000 Product inspections:

Gravity, API 61. 4 61. 8 61. 8 61. 7 61. 7 62. 4 62. 9 62. 3 64. 63. 5 63, 8 Aniline point, F 137. 9 146. 2 146. 5 144. 5 146. 4 145. 6 142. 4 134.0 146.0 146. 3 144. 5 Aniline-gravity product- 8, 467 9, 035 9, 054 8, 916 9, 033 9, 085 8, 957 8, 348 9, 345 9, 290 9, 219 Sulfur, parts per million 20 13 7 4 6 Lurninornetcr number 113 135 139 130 135 130-135 130 104 135 141 "130 Aromatic content, percent *Estirnatcd from correlation of luminometer number and aromatic content with aniline-gravity product.

It will be noted from the foregoing examples that the various catalysts tested differ in their ability to produce high L.N. jet fuel. Of the catalysts tried, those employing platinum as the hydrogenation component are the most effective in that satisfactory product may be obtained at lower temperatures and pressures and/ or higher space velocities than the other catalysts. The platinum containing reforming catalyst was the most effective.

The following Example VII gives the details of a complete operation according to this invention, using the platinum reforming catalyst.

EXAMPLE VII In an arrangement along the lines of the drawing, there is used as a charge stock to line 11 a West Texas naphtha with the following properties:

Initial boiling point, F. 150 End boiling .point, F. 380 Paraffins, vol. percent 66.0 Non-cyclic olefins, vol. percent 0.4 Cyclic olefins, vol. percent 0.4 Aromatics, vol. percent 5.8

Naphthenes, vol. percent 27.4 Sulfur, wt. percent 0.01

which is passed to pretreater operated with a cobalt molybdate catalyst under the following conditions:

Temperature, F. 650 Hydrogen pressure, p.s.i.g 300 Space velocity, vol./vol./hr. 5 Hydrogen circulation s.c.f./bbl. 500

whereby to reduce the sulfur content to about 0.0013 weight percent.

With use of a platinum reforming catalyst as described in Example I, for producing jet fuel, and reactor 29 operated under the following conditions:

Temperature, F. 500 Hydrogen pressure, p.s.i.g 300 Space velocity, v0l./vol./hr. 1 Hydrogen circulation, s.c.f./bbl. 10,000

a finished jet fuel having a LN. of at least 130, an energy content of 18,900 B.t.u. per pound, an initial boiling point of 150 F. and an end boiling point of 380 F. may be produced. For production of such a jet fuel, the hydrogen consumed would be on the order of 200 standard cubic feet per barrel.

When it is desired to reform rather than hydrogenate in unit 29, the temperature is raised to 800-900 F., and reformer is operated under conditions similar to unit 29 when it-is reforming.

As will be apparent from the foregoing description of the present invention, an important aspect of the invention is the selection of a suitable naphtha for hydrogenation in order to produce the jet fuels embodied herein. Whereas foregoing embodiments have been set forth, illustrating the production of such jet fuels from straight-run naphthas that possess the necessary components and component concentrations described hereinbefore, the following illustrates that hydrocarbon fractions, though they may be in the naphtha boiling range, are not necessarily suitable for practice of this invention.

EXAMPLE VIII From a highly parafiinic Kuwait crude, there was obtained a virgin gas oil, boiling mainly in the range of about 440 to about 616 F., which was subjected to hydrodesulfurization using a cobalt molybdate hydrodesulfurization catalyst at the following conditions: LHSV of 10, 700 F., 500 p.s.i.g, and a hydrogen circulation of 1000 s.c.f./bbl. From the product of such a treatment, there was obtained a make naphtha of the following I'Jpon hydrogenation with substantially complete saturation of the olefins and aromatics, such as naphtha produces a product that does not exceed about 100 LN.

EXAMPLE IX A catalytically cracked product, produced by subjecting a crude that is more naphthenic and aromatic than the Kuwait crude of Example VIII to TCC operation, and having the following properties:

Gravity, API 27.6 Distillation, F.:

I.B.P. 459 10% 502 50% 557 625 E.P. 654

was subjected to hydrodesulfurizaztion under the conditrons set forth in Example VIII. From the hydrodesulfurized product, there was obtained a make naptha of the following properties:

Gravity, API 38.4 Distillation, F.:

I.B.P. 200 5 274 Paraffins, vol. percent 16.2 Olefins, vol. percent 1.9 Naphthenes, vol. percent 10.7 Aromatics, vol. percent 71.2

Upon hydrogenation with substantially complete saturation of the olefins and aromatics, such a make naphtha produces a product that has a L,N. that does not exceed about 50.

This invention should be understood to include all the changes and modifications of the invention, herein chosen for purposes of disclosure, which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. A process for producing a high energy jet fuel which comprises contacting a charge naphtha that (1) boils in the range of about 150 to about 400 F. and (2) contains at least about 60 volume percent paraffins and noncyclic olefins, not more than about 38 volume percent naphtenes and 2 to about 40 volume percent aromatics with a solid hydrogenation catalyst in the presence of hydrogen to substantially hydrogenate unsaturates in said naphtha and produce a substantially saturated naphtha having a luminosity number of at least 130, said hydrogenation reaction conditions comprising a temperature of 300 to 750 F., a hydrogen partial pressure of 50 to 2000 p.s.i.g. and a space velocity of 0.1 to 10 volumes of charge naphtha per volume of catalyst per hour.

2. A process, as described in claim 1, wherein the hydrogenation catalyst contains a hydrogenation component selected from the group consisting of the metals having atomic numbers 44 to 46, inclusive, and 76 to 78, inclusive, nickel-molybdenum sulfide, tungsten disulfide and nickel-tungsten sulfide.

3. A process, as defined in claim 1, wherein the hydrogenation catalyst comprises from about 0.1 to 1 weight percent platinum on a base of at least one refractory oxide.

4. A process, as defined in claim 3, wherein the base is alumina.

5. A process, as defined in claim 1, wherein the catalyst comprises from about 0.1 to about 1 weight percent platinum deposited on alumina and the hydrogenation reaction conditions comprise a temperature of from about 500 to about 650 F., a hydrogen pressure within the range of about to about 500 p.s.i.g., and a space velocity in the range of about 0.1 to ten volumes of naphtha per volume of catalyst per hour.

6. A process, as defined in claim 1, wherein the catalyst comprises a platinum group metal on a base of at least one refractory oxide.

7. A process, as defined in claim 1, in which the charge naphtha has a sulfur content of below about 0.003 weight percent.

References Cited by the Examiner UNITED STATES PATENTS 2,769,753 11/1956 Hutchings et a1. 260667 2,902,436 9/1959 Mills et al. 208 2,965,564 12/1960 Kirschen-baum et al. 208143 3,000,815 9/ 1961 Haney 208-144 3,077,733 2/ 1963 Axe et a1. 260667 3,125,503 3/1964 Kerr et a1. 208-143 DELBERT E. GANTZ, Primary Examiner. ALPHONSO D. SULLIVAN, Examiner.

Claims

1. A PROCESS FOR PRODUCING A HIGH ENERGY JET FUEL WHICH COMPRISES CONTACTING A CHARGENAPHTHA THAT (1) BOILS IN THE RANGE OF ABOUT 150 TO ABOUT 400$F. AND (2) CONTAINS AT LEAST ABOUT 60 VOLUME PERCENT PARAFFINS AND NONCYCLIC OLEFINS, NOT MORE THAN ABOUT 38 VOLUME PERCENT NAPHTHENES AND 2 TO ABOUT 40 VOLUME PERCENT AROMATICS WITH A SOLID HYDROGANATION CATALYST IN THE PRESENCE OF HYDROGEN TO SUBSTANTIALLY HYDROGENATE UNSATURATES IN SAID NAPHTHA AND PRODUCE A SUBSTANTIALLY SATURATED NAPHTHA HAVING A LUMINOSITY NUMBER OF AT LEAST 130, SAID HYDROGENATION REACTION CONDITIONS COMPRISING A TEMPERATURE OF 300 TO 750*F., A HYDROGEN PARTIAL PRESSURE OF 50 TO 2000 P.S.I.G. AND A SPACE VELOCITY OF 0.1 TO 10 VOLUMES OF CHARGE NAPHTHA PER VOLUME OF CATALYST PER HOUR.