US3142635A - Production of lubricating oils - Google Patents

Description

y 1964 H. COONRADT ETAL 3,142,635

PRODUCTION OF LUBRICATING OILS Filed Oct. 27, 1961 ll H2 I2 I 23 AI Heater Gus Charge Nuphthu Distillation I3 I 5 Fuel on Gus Hydrocracking I6 20 29 l4 I5 I 8 T 2| (Dewoxing 27 n 32 Lube Oil F I Resldue Wax I30 3 z .2 r '2 Q no 3O 4O 5O 6O 7O 8O 9O Conversion to 650E+Produc1s Volume per cent INVENTORS Horry L. Coonrodt 8 F| G 2 William E.Gorwood ATTORNEY.

United States Patent Oflice 3,142,635 PRODUCTIGN F LUBRICATING OILS Harry L. Coonradt, Woodbury, and William E. Garwood,

Haddonfield, NJL, assignors to Socony Mobil Oil Company, Inc., a corporation of New York Filed Oct. 27, 1961, Ser. No. 148,060 8 Claims. (Cl. 208-111) This invention is directed to the production of high quality lubricating oils by hydrocracking high boiling hydrocarbons. More particularly it relates to the production of mineral lubricating oils with uniquely desirable properties from specified essentially non-lube hydrocarbon charge stocks by hydrocracking.

It has, of course, long been recognized that one of the most valuable products of the refining of crude mineral oils is lubricating oil. Common practice is to recover lubricating oil components by extracting undesirable components, such as sulfur compounds, oxygenated compounds and aromatics, from a straight run distillate fraction with a selective solvent. However, with the gradual decline in the availability of paraffinic base crudes and a corresponding increase in the proportion of naphthenic and mixed naphthenic and asphaltic base crudes it is becoming increasingly difficult to recover sufficient quantities. of components suitable for lubricating oils by extraction.

One method which has been suggested as a remedy of this situation is hydrogenation of high boiling hydrocarbon charge stocks which do not contain substantial quantity of lube oil components in order to produce such components. This suggestion has not been adopted generally, however, because the materials so produced have not been sufiiciently high in lubricating oil quality, since particular emphasis is now placed on high viscosity and high viscosity-index properties. By conventional refining pro cedures, the lubrication oils produced have attractive viscosities but poor viscosity-index properties. To compensate for the low viscosity-index, various expensive additives are added to the lubrication oil to improve viscosityindex but these additives readily break down under shear and lose their effectiveness. It is desirable, therefore, to provide a process to produce a lubrication oil which has both high viscosity and high viscosity-index properties wherein little or no expensive viscosity-viscosity-index improvers are required.

This invention involves a hydrocracking operation which produces very high viscosity index oils of a unique kind by a novel combination of charge stock, catalyst, reaction conditions and product finishing.

It is a principal object of this invention to provide an improved process for the production of mineral lubricating oils having viscosity indices greater than 115 and pour points below +25 F.

Another object of this invention is to provide a process for the transformation of materials which are not suitable for use as components of lubricating oils into high quality lubricating oils.

Another object of this invention is to provide a process for the manufacture of high quality lubricating oil components by hydrocracking.

These and other objects of the invention will be apparent from the following description of the invention.

Broadly, in this invention a high boiling straight run petroleum charge stock which has a fifty percent boiling point greater than 750 F. and a ninety percent boiling point greater than 850 F. is hydrocracked. The hydrocracking is effected by use of a'catalyst which has hydrogenation and cracking activity. The hydrocracking reaction is controlled so that the conversions of the high boiling straight run charge stocks to products having boiling points below 650 F. range from about 40 to about 93 3,l42,635 Patented July 28, 1964 volume percent, preferably in the range from about 50 to about volume percent. From this product a lubricating oil fraction is separated. This lubricating oil fraction is of such a boiling range that it does not include at least the lower boiling volume percent in the ranges from about 5 to 70 percent, preferably in the range from about 10 to about 50 percent, of the part of the product which boils above 650 F. This lubricating oil fraction is then dewaxed to produce a finished lubricating oil component.

This invention will be best understood by referring to the attached drawings, of which:

FIGURE 1 is a schematic flow diagram of a process operated according to this invention.

FIGURE 2 is a graph plotting the viscosity index of the lubricating oil fraction against the conversions of the high boiling straight run charge stocks to products boiling to 650 F. obtained from the hydrocracking step of this invention.

Referring to FIGURE 1, -a hydrocarbon charge is admitted to the system through line 10. This charge should be a high boiling straight run material. Charge stocks which have previously undergone catalytic conversion, such as cycle stocks from conventional catalytic cracking, are not suitable charge stocks for this invention. The charge stock should be sufficiently high boiling that its 50 percent point, as determined by the conventional vacuum assay method (ASTM D1160), is greater than 750 F. and its ninety percent point greater than 850 F. A typical charge can include a crude residuum, all of which boils above 650 F., with asphalt removed by eliminating the highest boiling 10 volume percent of the residuum or any petroleum residuum which has been deasphalted with a low boiling hydrocarbon such as propane, propylene, butane or the like. Thus, for instance, the charge for this invention can be prepared from various crudes such as Mid-Continent, Kuwait, West Texas and the like.

The charge stock is joined by hydrogen admitted through line 11, heated to the desired hydrocracking reaction temperature in heater 12 and admitted to hydrocracking reactor 13. The hydrocracking reactor is filled with a solid catalyst which has significant hydrogenation and cracking activity. Within the broad scope of this invention any catalyst which is useful as a combination hydrocracking and hydrogenation catalyst may be used. These' catalysts include the platinum on active cracking base hydrocracking catalyst described in US. Patent No. 2,945,806, and the catalyst comprising oxides of cobalt, molybdenum, silicon and aluminum described in copending US. Patent Application Serial No. 760,646, filed September 12, 1958, among others. Hydrogenation catalysts such as cobalt molybdate, nickel-tungsten sulfide, which do not have any substantial cracking properties are not considered desirable.

The conditions within the reactor 13 are controlled in order to produce conversions of the high boiling straight run charge stocks to products having a boiling range below. 650 F. Subject to this limitation the conditions used will depend very largely on the catalyst employed. The average reaction temperature will generally range from about 500 to about 1200 F., preferably from about 600 to about 900 F. A hydrogen pressure within the range to 10,000 p.s.i.g. and a molar ratio of hydrogen to hydrocarbon charge within the range about 2 to about 80 can be utilized. The liquid hourly space velocity of charge will normally fall within the range 0.1 to 10 volume charge (as 60 F. liquid) per volume of catalyst per hour. In preferred applications, the hydrogen pressure will be at least 1500 p.s.i.g., the hydrogen to hydrocarbon charge molar ratio at least 10 and the liquid hourly space velocity not in excess of 1.0.

Product is removed from reactor 13 through line 14 and cooled, for example, to about 100 F., by means of u) cooler 15 and then passed to a separator 16 maintained at about the pressure of the reaction zone. In separator 16 a gas stream consisting primarily of hydrogen is removed through line 17 and returned to reactor 13. It is feasible to remove impurities, such as ammonia and/ or hydrogen sulfide from this stream before it reenters the reactor.

Material flows from separator 16 through line 18 to separator 19 which is maintained at a low pressure, for example, about atmospheric to 50 p.s.i.g. The temperature in separator 19 would be substantially the same as in separator 16. Material that is in the gaseous phase under the conditions in separator 19, which will be predominantly low boiling hydrocarbons, is removed through line 20. The remaining liquid flows through line 21 to a fractionation column 22. The lowest boiling material is removed from fractionator 22 through line 23. A naphtha fraction, which typically might boil within the range 125 F. to 390 F. might be taken at line 24, and through line 25 a distillate fuel oil fraction boiling, for example, within the range 390 F. to 650 F., can be withdrawn.

The fraction containing the lubricating oil component is removed through line 26. There are no precise limits on the boiling range of this fraction. Broadly, this fraction can include everything which boils above 600 F. More usually however, this fraction will be limited to material boiling above 650 F. at the higher boiling end it will be desirable to exclude from the fraction removed through line 26 the highest boiling 1 to 10 volume percent of the material boiiing above 650 F., which may be removed through line 27.

Material from line 26 is passed to a topping unit 28. In this topping unit the lower boiling end of the fraction is removed by distillation in an amount such that at least volume percent and no more than 70 volume percent of the material boiling above 650 F. produced by the hydrocracking (this includes the material removed through line 27) is distilled from the lubricating oil fraction and removed through line 29.

The topped lubricating oil fraction is then passed through line 30 to a dewaxing unit 31 in which Wax is removed by any of the conventional processes available for this purpose. Examples of such procesess are urea dewaxing and soluent dewaxing using propane, or mixed soluents such as methyl ethyl ketone-toluene, propyl ketone-benzene, and the like.

The amount of material to be removed by topping depends on the viscosity and viscosity-index of the lubrication oil to be obtained. It is desired however, to remove the minimum amount of material so as to obtain the maximum yield of the superior lubrication oil. The amount of material to be topped depends on the boiling range of the charge stock to the hydrocracking unit, the catalyst, as well as the conditions used in the hydrocrackterial ranges from 5 to 10 volume percent of the hydrocracked products boiling above 650 F.

The finished lubricating oil component is removed through line 32. The dewaxing is conducted to produce a lubricating oil component having a specified pour point (as determined by ASTM D97). The pour point will depend on the particular use to which the lubricating oil component is to be put. Generally the pour point of the material removed at 32 should not exceed 25" F.

One of the critical factors in the process of this invention is the extent to which the hydrocracking is carried. This can be demonstrated by a number of examples which follow. Various charge stocks are used in these examples. The properties of these charge stocks are given in Table I.

TABLE I Designation A Name Guico 650 F.10.6 Vol. Percent Besiduum Guico Heavy Vacuum Gas Oil Gravity, API Vacuum Assay F.:

9 Pour P0int, F Kinematic Viscosity 210 F., cs -1 Several different catalysts were used in making the experiments on Which this invention is based. Among these are three different samples of platinum on silica-alumina catalyst of the type described in U.S. Patent No. 2,945,- 806. These catalysts had the properties enumerated in Examples 1 t0 7 The Guico residuum (Charge A) was hydrocracked using the platinum on silica-alumina catalysts A, B, and C while the Guico heavy vacuum gas oil (Charge B) was hydrocracked using the platinum on silica-alumina catalyst C. Seven runs were made under reaction conditions listed in Table III. Significant results are also listed in Table III. Viscosity index of the finished lubricating oil component is plotted against conversions of the high boilmg stra1ght run charge stocks to products having a boil-- ing process. In any event, a minimum amount of mamg point to 650 F. in FIGURE 2.

TABLE III Exmaple I 2 3 4 5 6 7 Charge Stock (Table I) A A A A A A B Catalyst (Table II) B A C C C C C Reaction Conditions:

H; Press p S 1 g 1,500 1, 500 2,000 2,000 2,000 2,000 2,000 0. 5 0. 0. 5 0. 5 0. 0. 5 0. 5 14, 500 14, 500 14, 500 14, 500 14, 500 14, 500 14, 500 40 4 4 40 40 40 53 738 785 747 765 775 780 783 Conversion 11. 9 97. 7 36. 4 70 9 85. 6 95. 3 70. 3 650+Hydrocracked Product:

Yield Percent Vol. of Charge 88.1 2. 3 63.6 29. 1 14. 3 4. 7 29. 7 gravitPy, 31. 2 g 40. 4 42.0 42. 7 39. 7 our oin 5 5 50 25 80 Hydrocracked Lube:

Yield, Vol. Percent of 650+ Product 74. 8 97. 0 75. 0 8G. 7 95. 0 100 88. 1 Yield, Vol. Percent of Charge 65. 9 2. 2 47. 7 25. 2 13. B 4. 7 26. 2 Gravity, API 28. 0 38. 3 35. 4 40. 5 42. 4 42. 7 39. 9 V1sr city 210 F 4. 74 2. 90 3. 64 3. 26 2. 87 2. 3. 56 Viscosity Index- 109 109 128 124 119 132 POur P011111 +35 +10 +30 +20 +10 +25 +25 In all'of the foregoing examples the properties of the lubricating oil component were obtained after dewaxing. In Examples 1 to 7, dewaxing was accomplished by con tacting the lubricating oil fraction at 0 F. with a solvent comprising 60 parts of benzene to 40 parts of methylethyl ketone in conventional manner.

Several significant points may be made based on the data of Table III and the curve of FIGURE 2. FIGURE 2 demonstrates that the severity of the hydrocracking must be controlled to obtain optimum viscosity index material. It is particularly significant that optimum viscosity index will be obtained when the conversion is within the range from about 40 to about 93 voliune percent regardless of the charge stock, catalyst and particular reaction conditions. This is not to say that there are not differences among catalysts and charge stocks but these differences are relatively minor.

Lubricating oil components having a viscosity index in excess of 125 after dewaxing to a pour point not over 35 F. can be produced with all of the catalysts and charge stocks.

It should be emphasized that the lubricants of this invention have the high viscosity indexes noted after they have been dewaxed. Some of the prior processes have been indicated to have high viscosity indexes before dewaxing. Since dewaxing is necessary and reduces the viscosity index, these processes would not give the quality of finished lubricant obtainable by this invention.

From the data in Table III it will be noted that the dewaxing necessary to provide finished lubricant will not be excessive since the pour point of the 650 F.+ product is substantially below the pour point of the charge stock rather than above it as in some of the prior art.

It is preferred that, in addition to removal of the low boiling end, the highest boiling 1 to percent of the hydrocracked 650 F. product be removed from the lube oil fraction. It is believed that by this means substantial amounts of undesirable polycyclic aromatics will be eliminated from the lube oil. This may be accomplished by distillation.

The lubricating oils of this invention are equal to or better than the highest quality lubricants produced by other processes as regards their stability to oxidation. To illustrate this, a portion of charge stock A (Table I) was dewaxed. Another portion was solvent refined with furfural. An oxidation stability test was conducted on these two oils and on the hydrocracked oil of Example 1. This test involved subjecting a 25 ml. sample of the oil to liters of air per hour for 40 hours in the presence of 15.6 sq. in. of iron wire, 0.78 sq. in. of copper wire, 0.87 sq. in. of aluminum wire and 0.167 sq. in. of lead surface. The temperature was maintained at 260 F. Results are given in Table IV.

The small changes in neutralization number and viscosity and the very low lead loss all show the hydrocracked oil to have superior oxidation stability.

Lubricating oils of this invention may be blended with conventional oils to produce a finished lubricant as desired. Additives may be used in these oils for specific purposes as they are used with conventional oils.

The catalysts which can be used in this invention include those comprising at least one of the metals having atomic numbers 44, 45, 46, 76, 77 and 78 deposited on a composite of the oxides of at least two of the metals of Groups IIA, IIIB, IVA and IVB of the Periodic Arrangement of the Elements, particularly where such composite has an activity index in excess of 25. Preferably catalysts include: 0.05 to 2-0 wt. percent of a platinum group metal deposited on a composite of at least two of the solid oxides of Groups IIA, IIIB, IV of the Periodic Arrangement of Elements, particularly where such composite has an activity index in excess of 25 and 1 to 8 weight percent cobalt oxide and 3 to 20 wt. percent molybdenum trioxide on a silica-alumina base containing silica in amounts from about 15 to about 40 weight percent. The more preferred catalyst is a platinum on alumina-silica catalyst of the type described in US. Patent Number 2,945,806.

As pointed out above, the charge stock may be any straight run fraction which has a 50 percent point greater than 750 F. and a percent point greater than 850 F. including residual stocks.

It should be understood that this invention includes all changes and modifications of the examples 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 manufacturing high viscosity-index lubricating oils from high boiling hydrocarbon fractions, which comprises: hydrocracking a straight run petroleum fraction which has a fifty percent boiling point greater than 750 F. and a ninety percent boiling point greater than 850 F. over a catalyst which has hydrogenation and cracking activity; controlling the hydrocracking conver sion of said straight run petroleum fraction to hydrocracked products having boiling points below about 650 F. until the range of about 40 to about 93 volume percent; separating a lubricating oil fraction boiling above 650 F. from the hydrocracked product; removing from about 5 to about 70 volume percent of the lower boiling portion of said separated lubricating oil fraction from a higher boiling residual fraction thereof and dewaxing the residual lubricating oil fraction to produce a superior finished lubricating oil blending stock.

2. A process for manufacturing high viscosity-index lubricating oils from high boiling hydrocarbon fractions, which comprises: hydrocracking a straight run petroleum fraction which has a fifty percent boiling point greater than 750 F. and a ninety percent boiling point greater than 850 F. over a catalyst selected from the group consisting of: catalysts comprising at least one of the metals having atomic numbers 44, 45, 46, 76, 77 and 78 deposited on a composite of the oxides of at least two of the metals of Groups IIA, IIIB, IVA and IVB of the Periodic Arrangement of the Elements, said composite having an activity index of greater than 25; controlling the hydrocracking conversion of said straight run petroleum fraction to products having boiling points of below 650 F. within the range of about 40 to about 93 volume percent; separating a lubricating oil fraction boiling above 650 F. from the hydrocracked product; removing from about 5 to about 70 volume percent of the lower boiling products of said separated lubricating oil fraction to produce a high boiling lubricating oil fraction and dewaxing the high boiling lubricating oil fraction to produce a superior finished lubricating oil blending stock.

3. The process of claim 1 wherein the catalyst comprising a composite of 3 to 20 weight percent molybdenum trioxide, 15 to 40 weight percent silica, 1 to 8 percent by weight cobalt oxide and the remainder alumina.

4. The process of claim 1 wherein the high boiling lubricating oil fraction has had the highest boiling 1 to 10 volumes percent thereof removed therefrom.

5. A process for manufacturing high viscosity-index lubricating oils from high boiling hydrocarbon fraction, which comprises: hydrocracking a straight run petroleum fraction which has a fifty percent boiling point greater than 750 F. and a ninety percent boiling point greater than 850 F. over a platinum on silica-alumina catalyst containing about 005 to about 2 weight percent platinum and about 10 to about 40 weight percent alumina; controlling the hydrocracking conversion of said straight run petroleum fraction to hydrocracked products having boiling points below about 650 F. within the range of about 50 to about 85 volume percent; separating a lubricating oil fraction boiling above 650 F. from the hydrocracked product; removing about 5 to about 70 volume percent of the lower boiling products thereof from said lubricating oil fraction and dewaxing the remaining oil fraction to produce a superior finished lubricating oil blending stock.

6. A method for producing a lubricating oil which comprises hydrocracking a deasphalted crude residuum boiling above 650 F. under condition to produce a hydrocracked product and obtain at least 40 volume percent conversion to products boiling below 650 F., recovering a hydrocracked product boiling above 650 F., topping the hydrocracked product boiling above 650" F. to obtain a high boiling lubricating oil fraction therefrom and dewaxing the thus obtained high boiling lubricating oil fraction.

7. A method for producing lubricating oils which comprises hydrocracking a straight run deasphalted residuum under a hydrogen pressure of at least 1500 p.s.i.g. and

temperature conditions to obtain at least volume percent conversion to products boiling below 650 F., and a higher boiling hydrocracked product, separating the higher boiling hydrocracked product under condition to remove at least 5 volume percent of the lower boiling portion thereof therefrom and not more than 10 volume percent of the higher boiling portion thereof to obtain an intermediate fraction thereof and dewaxing the thus obtained intermediate fraction to produce a desired lubricating oil.

8. A method for producing lubricating oils which comprises hydrocracking a straight run crude boiling above 650 F. at an elevated temperature and pressure to obtain conversion of the crude to hydrocracked products boiling above and below 650 F., recovering the hydrocracked product boiling above 650 F, topping the recovered hydrocracked product to remove about 10 volume percent therefrom and thereafter dewaxing the topped hydrocracked product to produce lubricating oils of a desired high viscosity index.

References Cited in the file of this patent UNITED STATES PATENTS 2,697,681 Murray et al Dec. 21, 1954 2,787,582 Watkins et a1 Apr. 2, 1957 2,799,626 Johnson July 16, 1957 2,945,806 Ciapetta July 19,. 1960 3,960,458 Beuther et al Nov. 15, 1960 .UNITED STATES PATENT OFFICE CERTIFICATE OF CURRECTIN Patent No. 3,142,635 July 28,, 1964 Harry L Coionradt 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 1, line 71, strike out "the" first occurrence; columns 3 and 4, TABLE. III under the heading "Example", line 8 thereof, for Temp.." read Temp. same table under the heading "4" line 8 thereof, for "'70 9"" read 7 70..9 column 6, line 37 for *until read within Signed and sealed this 1st day of December 1964,

(SEAL) Attest- ERNEST w. SWIDER' f EDWARD J. BRENNER Attesting ()fficer Commissioner of Patents

Claims (1)

1. 2. A PROCESS FOR MANUFACTURING HIGH VISCOSITY-INDEX LUBRICATING OILS FROM HIGH BOILING HYDROCARBON FRACTIONS, WHICH COMPRISES; HYDROCRACKING A STRAIGHT RUN PETROLEUM FRACTION WHICH HAS A FIFTY PERCENT BOILING POINT GREATER THAN 750*F. AND A NINETY PERCENT BOILING POINT GREATER THAN 850*F. OVER A CATALYST SELECTED FROM THE GROUP CONSISTING OF: CATALYSTS COMPRISING AT LEAST ONE OF THE METALS HAVING ATOMIC NUMBERS 44,45,46,76,77 AND 78 DEPOSITED ON A COMPOSITE OF THE OXIDES OF AT LEAST TWO OF THE METALS OF GROUPS IIA,IIIB,IVA AND IVB OF THE PERIODIC ARRANGEMENT OF THE ELEMENTS, SAID COMPOSITE HAVING AN ACTIVITY INDEX OF GREATER THAN 25; CONTROLLING THE HYDROCRACKING CONVERSION OF SAID STRAIGHT RUN PETROLEUM FRACTION TO PRODUTS HAVING BOILING POINTS OF BELOW 650*F. WITHIN THE RANGE OF ABOUT 40 TO ABOUT 93 VOLUME PERCENT; SEPARATING A LUBRICATING OIL FRACTION BOILING ABOVE 650* F. FROM THE HYDROCRACKED PRODUCT; REMOVING FROM ABOUT 5 TO ABOUT 70 VOLUME PERCENT OF THE LOWER BOILING PRODUCTS OF SAID SEPARATED LUBRICATING OIL FRACTION TO PRODUCE A HIGH BOILING LUBRICATING OIL FRACTION AND DEWAXING THE HIGH BOILING LUBRICATING OIL FRACTION TO PRODUCE A SUPERIOR FINISHED LUBRICATING OIL BLENDING STOCK.

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