US3284340A

US3284340A - Method for producing lubricating oils

Info

Publication number: US3284340A
Application number: US354620A
Authority: US
Inventors: Raymond R Halik; Henry R Ireland; Michael T Smilski
Original assignee: Mobil Oil Corp
Current assignee: ExxonMobil Oil Corp
Priority date: 1964-03-25
Filing date: 1964-03-25
Publication date: 1966-11-08
Anticipated expiration: 1983-11-08
Also published as: DE1545351A1; NL6503685A

Description

NOV- 3, 1966 R. R. HALIK ETAL METHOD FOR PRODUCNG LUBRICATING OILS Filed March 25, 3,964

United States Patent O M 3,284,340 METHOD FOR PRODUCING LUBRICATING UTLS Raymond R. Halik, Pitman, Henry R. Ireland, West Deptford Township, Gloucester County, and Michael T. Smilski, Mantua Township, Gloucester County, NJ., assignors to Mobil Oil Corporation, a corporation of New York Filed Mar. 25, 1964, Ser. No. 354,620 6 Claims. (Cl. 208-111) This application is a continuation in part of application Serial Number 159,340 filed December 14, 1961, now abandoned,

This invention relates to the conversion of asphaltcontaining petroleum fraction such as residual fractions for the production of valuable products therefrom. In a more specific aspect, the invention relates to the method of converting asphalt-containing residual oils in the presence of hydrogen to produce lube oils.

The characteristics of satisfactory lubricating oils and specic types of lubricating oils are known in the art. To provide lubricating oils which can be used for known and ever changing specific purposes and have acceptable characteristics, the refining processes generally require a careful selection of the crude base stock and an elaborate combination of refining steps sufficient to produce the desired product. It is desirable therefore to be able to supply the demands of the consumer by utilizing substantially any feed and particularly less desirable feeds in a refining process which minimizes the refining steps necessary to obtain desired valuable product such as lubricating Oils.

It is an object of this invention to produce valuable lubricating oils. It is another object of this invention to produce lubricating oils from asphaltic residuum. Other objects and advantages of this invention will become more apparent from the following discussion.

In one aspect the present invention relates to contacting an asphalt-containing petroleum feed such as a residuum derived from a petroleum crude oil and the like with a catalyst having hydrogenating and cracking characteristics in the presence of an excess of hydrogen and under conditions of conversion severity sufficient to produce lubricating oils having a V.I. of at least about 100. That is, the petroleum fraction used in the process of this invention is an asphalt-containing hydrocarbon boiling above about 650 F. obtained by vacuum distillation and/ or from atmosphere distillation of an asphalt-containing crude oil and having an asphalt content in the range of from about 2 to about 70 volume percent and more usually, for example, in the range of from about 5 to about 40 volume percent of the charge stock. The term asphalt as used herein is dened as the amount of asphalt tar which can be removed from the asphalt-containing hydrocarbon charge stock by propane deasphalting. If the asphaltic feed starting material is not sufliciently fluid, a suitable hydrocarbon diluent may be added to provide a desired fluidity.

In a more specific form of this invention, an asphaltic residuum combined with an excess of hydrogen is passed through a catalyst mass comprising a siliceous base promoted with one or more components having hydrogenating activity under relatively narrow temperature conditions of from about 700 to about 900 F. preferably below about 850 F. while maintaining the pressure above about 1500 p.s.i.g. and the hydrocarbon reactant space velocity through the mass of catalyst substantially below about 1.0 and preferably below about 0.5 liquid hourly space velocity (v./v./hr.). It is preferred in the method herein described to maintain a reaction pressure above about 2000 p.s.i.g. and a temperature preferably below about 850 F, while maintaining the reactant space velocity below about 1.0 and preferably in the range of from about 0.1 to about 0.50. The conversion conditions used in the method of this invention are, therefore, relatively severe conversion condition to obtain hydrocracked products suitable for separating lubricating oils boiling above about 650 F. therefrom which upon dewaxing produce lube oils having a V.I. above about 100. In addition to the above, it has been found quite unexpectedly that when -a portion of the conversion product boiling within the range of from about 400 F. to about 650 F. or 700 F. is combined with the fresh asphaltic feed as a recycle fraction that lube oil product having a V.I. in excess of may be readily obtained provided the pressure during conversion is at least 2000 p.s.i.g. and the space velocity subvstantially below 1.0 v./v./hr. That is, it has been found when employing the recycle operation herein described that a more viscous lubricating oil is obtained at substantially the same conversion severity as obtained in the single pass operation. On the other hand, single pass operation may be used to advantage for the production of lube oil having a V.I, of at least about by employing higher pressures up to about 3000 p.s.i.g. or higher and elevated temperature conditions provided the liquid hourly space velocity of the feed is maintained substantially below about 1.0 and preferably not substantially above about 0.20 LHSV.

The hydrocracking reaction conditions employed herein are maintained to provide a conversion which is generally in the range of from about 15 to about 70 volume percent and preferably in the range of from about 25 to about 45 volume percent of the asphalt-containing hydrocarbon feed. The term conversion as employed herein refers to the amount of product boiling below 650 F. obtained by the method and under the hydrocracking condition described herein.

Generally speaking, the catalyst employed in the method of this invention may be any hydrogenating catalyst having cracking activity, it being preferred to employ a siliceous base catalyst promoted with one or more hydrogenating components. Accordingly, the catalysts may include the oxides and suliides yof the metals of Group VLB of the Periodic rfable or mixture thereof, such as chromium sulfide, molybdenum sulde, tungsten sulfide and the like; oxides and sulfides of Group VIII of the Periodic Table or mixtures thereof such as the suldes of iron, cobalt, nickel, palladium, platinum, rhodium, osmium, iridium; mixtures of the above oxides and suliides of the metals of Groups VB, VIB, and VIII such as mixtures of nickel sulfide and tungsten sulfide, cobalt and molybdenum oxide or sulfide. The hydrogenating component is deposited on a cracking component preferably a siliceous cracking component such as silica-alumina, silica-magnesia, silicazirconia, silica-alumina-zirconia. Furthermore, the catalyst may contain a halogen promoter such as chlorine or fluorine in amounts up to 10 or 15% by weight. In a preferred embodiment, the catalyst employed in this invention is a siliceous base catalyst combined with one or more elements selected from the group consisting of alumina, magnesia, and zirconium to which a hydrogenating component such as cobalt and molybdenum has been added. A preferred catalyst includes from about 1 to 8 weight percent cobalt, 3 to 20 weight percent molybdenum in the oxide or sulfide form on a silica-alumina or silicazirconia base containing silica in amounts ranging from about 5 to about 95 weight percent.

The quantity and purity of a gas stream containing hydrogen employed with the asphaltic feed to be hydrocracked by the method herein described is generally sufficient to provide a substantial excess of hydrogen in the range of from about 5000 to about 20,000 s.c.f./b, whether obtained by use of a relatively low purity hydrogen stream or a high purity hydrogen-rich stream. The hydrogen concentration may be as low as 5000 s.c.f./b. of charge, however, it is preferred to employ a much higher concentration which is preferably of the order of about 10,000 s.c.f./b. It is to be understood, of course, that it is preferred to employ hydrogen-rich gas streams which have been treated to remove Water, ammonia and sulfur compounds therefrom.

The product effluent of the hydrocracking conversion process obtained by hydrocracking an asphaltic residuum in accordance with the method of this invention is thereafter separated such as by distillation into desired fractions including naphtha boiling material, a recycle fraction boiling generally from about 400 F. to about 700 F. and hydrocracked fractions boiling above about 600 F. and preferably above about 650 F. The hydrocracked product fraction boiling above about 600 F, or 650 F. is thereafter dewaxed under conditions sufficient to produce the desired high V.I. lubricating oils. Removal of waxy lmaterial in desired amounts is accomplished by any of the well-known techniques used to Igive desired low pour point oils. Dewaxing to obtain exceptionally low pour points is essential for some lubes and may be accomplished with one or more steps of solvent extraction with a solvent such as propane, methyl ethyl ketone, toluene and others with suitable chilling and filtering between steps followed by recovery of the solvent by distillation. Dewaxing of the hydrocracked product boiling above 650 F. is a part of this invention only to the extent required to obtain desired pour point lube oils. Of course, the lubricating oils produced by the process and method described herein may be combined with known additives to produce desired and improved lube oils. Examples of some additives which may be incorporated in the lube oil include V.I. improvers, thickeners, detergents, antioxidants pour point depressants and rust inhibitors may also be added in the amounts known in that specilic art.

To obtain improved turbine oils by the method of this invention, the hydrocracked product of the asphalt-containing hydrocarbon feed is separated so as to provide a fraction having a viscosity at 210 F. in the range of from about 40 to about 70 S.S.U. and a ash point of from about 390 F. to about 450 F. This fraction which can be obtained by distillation of the hydrocracked product can be used in its entirety as the improved turbine oil or separated fractions thereof can be blended to produce light, medium, or heavy turbine oil product.

In yet a further embodiment of the method of this invention, it has been found that the turbine oils may be further improved unexpectedly by percolating the turbine oil obtained from -the hydrocracked product through an 'adsorbent material such as activated clay, bauxite, porocel, fullers earth and activated charcoal. The turbine oil fraction can be passed through the bed of adsorbent material employing a volume ratio of oil to adsorbent in the range of from about 0.1 to about at a temperature of from about 50 F. to about 500 F. and preferably in a volume ratio of 2 to 5 volumes of oil per volume of adsorbent at a temperature in the range of from about 120 to about 300 F.

To 'obtain improved automatic transmission fluid base stocks by the method of this invention, the hydrocracked product of the asphalt-containing hydrocarbon feed is separated so as to provide a fraction having a viscosity at 210 F. in the range of from about 40 to about 50 S.S.U., a Hash-point of from about 390 F. to about 425 F., and a viscosity index in excess of 115. This fraction can also be obtained by distillation of the hydrocracked produc-t and can be used in its entirety as an automatic transmission fluid base stock or `separate fractions thereof can be blended to produce automatic transmission fluid of particularly desired properties.

The lubricating oil components separated from the hydrocracked product generally contain some wax constituents which are desirably removed to produce selected lube oils. Removal of wax, if desired, may be accomplished by any known treatment for dewaxing oils to give a pour point below about 20 F., preferably in the range from about 20 to about 5 F. for turbine oils. Since the automatic transmission fluid requires a low wax content, it is essential that these oils be dewaxed at temperatures to provide oils having pour points below about 10 F. Dewaxing to obtain exceptionally low pour points is essential for automa-tic transmission fluid base stocks so as to decrease the amount of pour depressant-viscosity index improvers required to provide an oil which can be used in extreme cold weather climates lw-thout solidifying. The deep dewaxing operation generally decreases the viscosity index of the base oils 5 to 10 points and signilicantly demonstrates the necessity of the untreated base oil having a high viscosity index preferably in excess of about 115. With extreme or deep dewaxing operation, therefore, the dewaxed base oils having viscosity indexes in excess of about can be obtained which decreases the amount of a viscosity index improver material necessary to obtain a high viscosity-index transmission uid. Typical of a satisfactory dewaxing process is the method wherein the oil is dissolved in a solvent, such as, propane; methyl ethyle ketone and toluene; and the like, cooling and ltering. The dewaxing solvent Ican be removed by distillation.

The turbine oils and the automatic transmission fluid base stocks obtained from the hydrocracked hydrocarbon may ycontain undesirable properties, such as sludge-producing components or undesirable color characteristics. These properties can be significantly improved, as discussed above, by percolating the lubricating oils such as the turbine oil, the automatic transmission liuid base stock, or the like through any of the well-known clay adsorbent material available for this purpose.

The lubricating oils including turbine and automatic transmission fluids which may be produced by the process of this invention can also be further improved by the addition of suitable additives. Examples of additives which may be incorporated in the lubricating oils obtained by the method herein described are the known viscosity-index improvers such as isobutylene polymers, methacrylate and the like and detergents including those of the class of metal sulfonates, metal phenates, and metal naphthenates. Additional additives which can be used include antioxidants such as zinc dithiophosphates, alkylated phenols and the like and known rust inhibitors, if desired, such as those of the class of amine derived succinic anhydrides. Other additives known in the art may be added to obtain additional desired effects.

The hydrocracking process of this invention may be carried out in any equipment suitable for effecting catalytic hydrocracking operations. The process may be operated batchwise, however, it is preferred to operate continuously in a process adapted to operate using one or more fixed beds of catalyst. It is contemplated in an embodiment, however, of using a moving bed of catalyst wherein the hydrocarbon tiow can be concurrent to or countercurrent to the catalyst tiow. A iiuid type of operation can also be employed if desired.

Significantly important advantages are realized in using the processes of this invention over known acid treatment and/ or solvent refining procedures for producing lubricating oils. That is, higher yields are obtainable since the lubricating oil fraction of the charge stock is hydrocracked under conditions to convert undesirable asphaltic materials into acceptable products thereby utilizing a greater portion of the crude charge stock including asphaltic material to produce the lubricating oils of this invention. On the other hand, the acid treating and solvent refining procedure removes the undesirable material from the charge stock thereby decreasing the yield of the resulting product. Not only are higher yields obtained in the process of this. invention, but lubricating oils are produced which hay@ improved resistance characteristics to chemical breakdown during use, maintain their body under hightemperatures (shear stability) and maintain their stability under oxidizing conditions. Having thus provided a general description of this invention, the following examples are presented to illustrate the processes and improved products of the invention without unduly limiting the same:

EXAMPLE 1 The properties of the charge stocks used in the hydrocracking process are listed in Table I.

The catalysts utilized were prepared by separately impregnating cobalt oxide and molybdenum oxide on a silicaalumina (CMAS) or silica-zirconia (CMZS) base and suliiding the catalyst composite. The resulting catalysts possessed the following compositions and properties:

CMZS CMAS A1203, weight percent 74. 2 S 2, weight percent.-. 78. 3 15. 4 ZrOQ, weight percent. 10. 6 M003, Weight percent. 8.5 8. 1 CoO, weight percent 2. 6 2. 3 Sulfur content, weight percent 6. 7 3. 8 Packed density, g./cc 0.93 0.98 Surface area, 11m/g. 373 241 Pore volume, cc./g 0. 27 0. 38 Average pore diameter, A 29 64 The propane deasphalted Mid-Continent railinate, the Mid-Continent 10% residuum and the Pan Fullerton 15% residuum Were hydrocracked over the CMAS catalyst described above, using the following conditions:

Hydrocracking Conditions:

Pressure, p.s.i.g 3,000 3, 000 3, 000 Temperature, F 779 820 800 Liquid hourly space velocity. 0.2 0.2 0. 2 H2 Circ. s.C.f./b 10, 000 10,000 10, 000 Conversion, percent volume 46 70 48 The hydrocracked products were distilled to separate from the total liquid product, fractions suitable for turbine oils having the properties described in Table Il below:

An oxidation stability test was conducted on each of the hereinafter described turbine oil fractions. This test involved subjecting a 25 milliliter sample of the oil to 15 liters ofair per hour for 40 hours in the presence of 15.6 square inches of iron wire, 0.78 square inch of copper wire, 0.87 square inch of aluminum wire and 0.167 square inch of lead surface. The temperature was maintained at 260 F. Results are given in Table II.

Table 1I PROPERTIES OF TURBINE OIL FRACTIONS Deasphalted Mid-Conti- Pan Fullerton Initial Viscosity Mid-Continent 10% 15% residunent residuum um S.S.U. at 210 F 41. 2 53. 2 41.0 52.1 Kinematic viscosity at mg. KOH/gm 0.06 0.08 0.05 0.1

OXIDIZED OIL TEST Kinematic viscosity at t crease, percent 283 295 6. 5 7. 47 Neutralization number,

mg. KOH/gm 18.1 16.1 1. 5 1. 5 Lead loss, mg 155. 3 214. 4 0.8 0. 9

The small changes in neutralization number and viscosity and the low lead loss of the fractions obtained from the asphalt-containing hydrocarbons demonstrates the superior oxidation stability of these turbine oils over those fractions of the deasphalted hydrocarbons. This advantage aids in eliminating or reducing antioxidant additives required of a turbine oil. The above comparison also shows the improved characteristics of the hydrocracked turbine oils obtained from the asphalt-containing hydrocarbons in that these oils maintained their low viscosity during use and significantly suppressed acid formation over the hydrocracked turbine oils obtained from the deasphalted residuum. As should be realized, the turbine oil fractions obtained from the hydrocracked asphaltcontaining petroleum hydrocarbons are suitable for use as lubricating oils to which lubricating oil additives can be added if desired.

EXAMPLE 2 The turbine oils of this invention can be further improved by the addition of conventional or known turbine oil additives. The following hydrocarbon charge stocks were hydrocracked utilizing the hydrocraeking conditions as described below using the CMZS catalyst described in Example 1.

Mid-Continent Deasphalted 25% residuum Kuwait residuum Gravity, API 19 .6 20.3 Pour point, F. 75 100 Vacuum assay,

5% vol 693 960 10% vol 755 986 50% VOL..- 1,011 1, 081 EP 1,087 at 67% 1,114 at 56% Kinematic viscosity at 210 F., cs. 32.9 36 .1 S.S.U. at 210 F 155 170 Asphalt, volume percent, 26 0 Hydroeraeking conditions:

Pressure, psig 3,000 3, 000 Temperature, F 764 750 Space velocity 0.2 0.2 Hg circ., s.c.t'./b 10,000 10, 000 Conversion, percent volume 33 42 The hydrocracked products were distilled and a light turbine oil fraction from each hydrocarbon charge stock was obtained having the following properties:

and dewaxed Light turbine oil from Light turbine oil from deas- For comparison purposes, a light turbine oil was obtained directly by the conventional refining of an East Texas Crude. This turbine oil without the benefit of hydrocracking had the following properties:

Gravity, API 32.1 Pour point, F. 20 Flash, F 395 S.S.U. 100 F. 153 S.S.U. 210 F. 43.5 V.I. 102 Neutralization number, mg. KOH/ g. 0.03

Each of the above-described turbine oil base stocks were mixed with conventional turbine oil additives in the following formulation:

Weight, percent Turbine oil base stock 99.61 2,6-dietertiary butyl paracresol 0.25 Zinc dihexyl dithiophosphate 0.10

Oleic acid-tricthylene tetramine-tetrapropenyl succinic anhydride reaction product 0.04

Ea-ch of the above-described formulations were subjected to a Test for Oxidation of inhibited Steam Turbine Oils as described in the ASTM Manual under Specification No. D943-54. The following results of Table III were obtained.

bine oill obtained from the asphalt-containing hydrocarbon until after 2100 hours of the oxidation test.

EXAMPLE 3 A portion of a 25% Mid-Continent residuum charge stock having the properties as described Iin Example 2 was hydrocracked over a sulfided catalyst composed of cobalt oxide and molybdenum oxide on a silica-zirconia base (properties described in Example 1) utilizing the following hydrocracking conditions:

Reaction temperature for conversion, F. 778 Pressure pounds per square inch gauge 3000 Liquid hourly space velocity (fresh feed) 0.2

Hydrogen circulation ratio, s.c.f. per barrel of fresh feed 10,000 Operation, single pass (once-through).

T able Ill Time of test, hours 270 i 3,500 I 5,000 i 5,700 0,400 l 7,000 l 7,000

Neutralization number, mg. of KOH/g.:

Hydrocracked turbine 011 obtained from a deasphalted residuum Hydroeracked turbine oil obtained from an asphalt-containing residuum.. Hydrocracked turbine oil obtained from an asphalt-containing residuum ith Percolation treatment Conventional turbine oil (not hydrocracked).

The results of the turbine oil stability test are plotted in the accompanying figure wherein the time of the test is plotted vs. the neutralization number, m-g. KOH/ g. of the formulated turbine oil. For turbine oils, the absolute tolerability of acidity is reached when the neutralization number reaches 2. The figure significantly demonstrates that the formulation of the turbine oil obtained from the hydrocracking of an asphalt-containing hydrocarbon followed by percolation can be used 1900 Ihours longer than the unpercolated hydrocracked turbine oil obtained from an asphalt-containing hydrocarbon for the formation of tolerable acid in the test turbine oil. 'The gure further demonstrates that the formulation of the percolated turbine oil obtained by hydrocracking an asphalt-containing hydrocarbon is approximately 4 to 8 times more stable, i.e. for the formation of tolera-ble acid, than the turbine oil obtained from the hydrocracked deasphalted residuum and the turbine oil obtained directly from :a typical crude oil. The improved formulations4 of this invention provide for a more stable turbine oil which maintains the desired property characteristics over an extended life period.

An additional advantage observed in the test for Oxidation of Inhibited Steam Tunbine Oil relates to the formation of sludge in minor amounts at 300 hours for the unpercolated hydrocracked turbine oil obtained from the asphalt-containing hydrocarbon, whereas no evidence of sludge Iwas observed in the percolated hydrocracked turzirconia base (properties desscribed in Example 1) utilizing the following hyd-rocracking conditions:

Reaction temperature for 45% conversion, F. 790 Pressure, pounds per square inch gauge 3000 Liquid hourly space velocity (fresh feed) 0.2 Hydrogen circulation ratio, s.c.f. per barrel of fresh feed 10,000 Operation Liquid recycle The following comparative results of the single pass and recycle operations were obtained as described in Table 1V below:

*Utilizing similar conditions as the single pass operation, the catalyst; aging rte was so low that a number could not be determined and assigne The use of a recycle stock boiling below lubricating oil stocks (400 to 700 F.) in the hydrocracking operation signiiicantly improves the catalyst aging rate over the rate of the single pass operation. This recycle operation Will extend catalyst life and periods of operation before regeneration is necessary over the single pass operation. ln addition to the improved catalyst aging characteristics, the recycle operation utilizing the hydrocracked product boiling in the range of about 400F.- 700 F. provides a higher viscosity of the lubricating -oil products boiling :above 650 F. and higher viscosity indices of a particular oil fraction than the single pass operation and the recycle 'operation utilizing a heatvy hydrocracked cycle stock boiling in excess of 850 F. These results indicate that a specific hydrocrafcked cycle stock (400-700 F.) can be used to obtain additional advantages of extended catalyst life and improved product characteristics.

EXAMPLE 4 An automatic transmission uid base stock Was obtained by hydrocarcking a portion of a 25% Mid-Continent residuum (properties described in Example 2) over a sulded catalyst composed of cobalt oxide and molybdenum oxide on a silica-zirconia base (preparation and properties described in Example 2) at a temperature of 782 F., a conversion level of 51 volume percent (100- material in the product boiling above 650 F. expressed as volume percent of charge) a pressure of 3000 pounds per square inch gauge, a liquid hourly space velocity of 0.2, and a hydrogen circulation ratio of 10,000 s.c.f. per 'barrel orf charge. The resulting hydrlocracked product was distilled to obtain a lfraction having a viscosity 2101F. of 42 S.S.U. This fraction was defwaxed at 35 F. to obtain a pour point of 15 F. and viscosity index of 115. This fraction demonstrates the same resistance to the oxidation reactions as the hydrocracked turbine oil in Example 1.

A iconventional automatic transmission fluid base stock was prepared Iby blending a solvent refined paraflinic neutral oil designated as A, and a solvent refined coastal distillate oil designated as B. These oils have the following properties:

ie pared by the formulation of the above-described stocks and additives:

Base stock, weight percent Hydrocraeked Conventional Hydrocraeked base stock 88 .8 Stock A 35.7 Stock B 53 .5 Additives:

Conventional viscosity index imprevers- Methaerylate polymer. 3.0 3.0 Iso-butylene poly1ner 3.0 2.6 C onventional detergents:

Barium wax benzene-sulionate oleate 3.0 3 .0 Barium phenate 1.0 1.0 Wax phenol sulonate 1 .0 1.0

PROPERTIES OF lI-IE AUTOMATIC TRANSMISSION FLUIDS Hydrocraeked Conventional Viscosity:

S.S.U.at 210 F 51.5 51.5 S.S.U. at F 183 205 S.S.U. at 0 F. (extrapolated) 4, 100 6, O00 Viscosity index 139 Brookeld viscosities:

Gps. at 0 F 1,040 1,750 Gps. at -30 F- 7, 410 16,000 Flash point F 425 380 Pour point, F -35 -35 Shear stability: 10 minutes, Sonic Oseillator; Final S.S.U. at 210 F 47.0 47.4 Foam ASTM D-892-46-T: Sequence 1,

Tendency-ml nil nil Rubber swell, Ford 91-48: 70 hours at 300 F. percent volume change 2 .8 2 .5

As is demonstrated in the above example, the hydrocracked automatic transmission fluid formulation using Conventional additives is a less Viscous oil at lower temperatures and has a higher viscosity index than a conventional automatic transmission fluid using the equivalent amounts of the same additives (see S.S.U. viscosities at 100 F. and 0 F.). The comparative data of the Brookiield Viscosities at 0 F. and -30 F. indicates that the viscosity of the hydrocracked transmission fluid ranges from about 1.7 to about 2 times less viscous than the conventional transmission fluid. Other physical properties of the hydrocracked transmission fluid are as good or better than the conventional transmission fluid. Obtaining a low viscosity at low temperatures is a specific requirement nec essary of a transmission fluid when used for lubrication in extremely cold climates and avoiding solidiiication of said iluid.

EXAMPE 5 Lubricating oils were prepared in a single pass `operati-on using a Mid-Continent 25% residuum hereinbefore described by hydrocracking in the presence of the cobaltmolybdenum-silica-alumina catalyst hereinbefore described. Table V below presents the results -obtained in this operation when studying the eiect of pressure with respect to the liquid hourly space velocity (LHSV) employed.

Table V SINGLE PASS Yield, percent 650 F.ideWaxed oil Run No. Press., LHSV Avg. Temp., vol. waxy p.s.i.g. F. 650 F.l-btms.

SSUat210F. V1.

3, 000 0.2 fresh feed 844 15. 2 36. 7 137 800 50. 1 45. 2 108 870 46. 7 44 70 860 52. 1 52. 4 G3 RECYCLE OPERATION 5 3, 000 0.2 fresh feed-l-O.2 805 46. 6 45. 8 116 liquid recycle. 2, 000 do 805 50. 2 47. 8 118 ,50o 795 52. 1 e5. s 105 1, 000 801 59. 0 78. 5 80 *1 to 1 vol. of 40G-700 F. boiling traction combined with fresh feed.

It is clear from the data presented above, Table V, that to obtain high lube oil V.I.s above about 100 by hydrocracking asphaltic crudes either a single pass or recycle operation requires the use of relatively high pressures of at least 1500 p.s.i.g. in conjunction with relatively low temperatures and particularly a space velocity (LHSV) which is substantially less than 1.0. Generally speaking, low temperatures permit the use of lower pressures provided the space velocity is kept significantly below 1.0. Furthermore, the data indicate that the recycle operation permits the use of lower pressures to obtain high V.I. lubes than is obtainable by the single pass operation. More importantly, however, the data establish the importance of using low LHSVs substantially below about 1.0 to produce desired high* V.I. lubes and that the use of LHSVs of about 1.0 cannot be satisfactorily overcome by the use of high pressures with low temperatures for the production of lubes having a V.I. above about 100.

Having thus provided a general description of the method of this invention and presented specific examples in support thereof, it is to be understood that no undue restrictions are to be imposed by reasons thereof except as defined by the following claims.

We claim:

1. A method for hydrocracking asphalt-containing residuums for the production of lube oils which comprises passing an asphaltic residuum containing from about 2 to about 70 volume percent asphalt at a cracking temperature below about 900 F. in the presence of an excess of hydrogen in contact with a siliceous base hydrocracking catalyst at a space velocity below about 1.0 while maintaining the pressure above about 1500 p.s.i.g. and recovering a hydrocracked product therefrom .suitable for producing lube oils.

2. A method for producing lubricating oils which comprises passing a residuum containing from about 2 to about 70 volume percent asphalt with hydrogen at a pressure above 1500 p.s.i.`g. and a temperature below about 850 F. in contact with a hydrocracking catalyst under condition to maintain the fresh feed reactant space velocity below about 1.0 to thereby produce hydrocracked product material, and recovering hydrocracked product material boiling above 60 F. for dewaxing to produce lube oils.

3. A method for producing lube oils which comprises hydrocracking a reactant comprising a residuum containing from about 2 to about 70 volume percent asphalt combined with a portion of the separated hydrocracked product boiling above about 400 F. obtained as hereinafter described with hydrogen in contact with a hydrocracking r catalyst at a temperature in the range of from about 800 F. to about 850 F. and a pressure of at least 2000 p.s,i.g. while maintaining the lreactant space velocity below about 0.5 v./v./hr., recovering a hydrocracked product, separating the hydrocracked product to recover a first fraction boiling above about 400 F. from a second fraction boiling above about 650 F. dewaxing the fraction boiling above 650 F. to produce lube oils of at least 115 V.I. and thereafter removing sludge forming materials by percolating the dewaxed lube oil through a clay like adsorbent.

4. A hydrocracking process which comprises passing a residuum containing from about 2 to about 70 volume percent asphalt with an excess of hydrogen at a liquid hourly space velocity less than about 0.5 in contact with a siliceous Ibase hydrocracking catalyst at a pressure above about 1500 p.s.i.g. and a temperature below about 850 F., recovering a hydrocracked product eiuent, recycling a portion of the product effluent boiling above about 400 F. for admixture with the asphaltic residuum feed passed to the process, recovering hydrocracked lube oil product effluent boiling above about 650 F. and thereafter dewaxing and percolating through a clay adsorbent the lube oil product for the preparation of dewaxed lubricating oils.

5. A method for converting residual hydrocrabons containing from about 2 to about 70 volume percent asphaltic constituents `which comprises passing the asphaltic residual oil with hydrogen at a pressure above 2000 p.s.i.g. and at a temperature below about 850 F. in contact with a siliceous base cracking component promoted with one or Groups VIB and VIII of the Periodic Table, said contact being effected at a space velocity below about 0.4 v./v./ hr., recovering a hydrocracked product fraction lboiling above about 650 F. and percolating the thus obtained hydrocracked product fraction to produce lube oils having a V.I.in excess of about 100.

6. A method for cracking asphaltic residuum in the presence of hydrogen which comprises passing a residuum containing from about 2 to about 70 volume percent asphalt combined with an equal volume of hydrocracked product boiling above about 400 F. obtained as hereinafter described with an excess of hydrogen at a liquid hourly space velocity substantially less than about 1.0 in contact with a hydrocracking catalyst maintained at a temperature below labout 850 F. and a pressure during said hydrocracking sufficiently above about 1500 p.s.i.g. to permit recovering a hydrocracked product fraction boiling above 650 F. which upon dewaxing will produce lube oils of at least V.I.

References Cited bythe Examiner UNITED STATES PATENTS 1/1961 Cole 20S-18 7/1964 Coonradt et al 208--111 UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No. 3,284,340 November 8, 1966 Raymond R. Halk et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column l0, line 49, for "EXAMPE" read EXAMPLE column l2, line Z6, after "or" insert more hydrogenatng metal components selected from Signed and sealed this 12th day of September 1967.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD I. BRENNER Attesting Officer Commissioner of Patents

Claims

2. A METHOD FOR PRODUCING LUBRICATING OILS WHICH COMPRISES PASSING A RESIDUUM CONTAINING FROM ABOUT 2 TO ABOUT 70 VOLUME PERCENT ASPHALT WITH HYDROGEN AT A PRESSURE ABOUT 1500 P.S.I.G. AND A TEMPERATURE BELOW ABOUT 850*F. IN A CONTACT WITH A HYDROCRACKING CATALYST UNDER CONDITION TO MAINTAIN THE FRESH FEED REACTANT SPACE VELOCITY BELOW ABOUT 1.0 TO THEREBY PRODUCE HYDROCRACKED PRODUCT MATERIAL, AND RECOVERING HYDROCRACKED PRODUCT MATERIAL BOILING ABOVE 60*F. FOR DEWAXING TO PRODUCE LUBE OILS.