US3053760A - Preparing bright stocks by hydrogenation - Google Patents

Description

,an an Patented Sept. 11, 1962 tic 3,053,760 PREPARING ill-EIGHT STOQKS BY HYDROGENATTON Alfred M. Henke, Springdale, and Joseph B. McKinley,

New Kensington, Pa, assiguors to Gulf Research 8;

Development Company, Pittsburgh, Pa, a corporation of Delaware No Drawing. Filed Mar. 4, 1960, Ser. No. 12,696 2 Qlaims. (Cl. 208-264) This invention relates to improved procedure for preparing refined lubricating oils and in particular to improved procedure for preparing bright stock.

It is well known that lubricating oil stocks can be improved by treating them with hydrogen in the presence of a hydrogenation catalyst at elevated temperature and pressure. These reaction conditions are selected so as to result in hydrogenation of minor constituents but without resulting in extensive splitting or extensive alteration of the hydrogen-to-carbon ratio. These procedures have been applied to lighter lubricating oils such as distillate lubricating oil stocks in the SAE SW-SAE 40 viscosity ranges and to a lesser extent to heavier lubricating fractions. Although these procedures result in a marked improvement in the lubricating oil, further advances in this respect are desirable.

This invention has for its object to provide improved procedure for preparing superior lubricating oils by treatment of lube oil stocks with hydrogen in the presence of a hydrogenation catalyst at temperatures and pressures resulting in relatively little splitting of carbon to carbon bonds. A still further object is to provide improved procedure for preparing superior bright stock type lubricating oils. Other objects will appear hereinafter.

These and other objects are accomplished by our invention which includes subjecting a lubricating oil stock which is substantially free of asphaltic materials to treatment with hydrogen in the presence of a hydrogenation catalyst deposited upon a carrier which is predominantly Eta alumina under reaction conditions which do not result in substantially splitting to form lower boiling hydrocarbons. We have found that by operating in this manner a finished lubricating oil having superior properties can be obtained. According to another aspect of our invention we subject a crude lube oil feed of the bright stock boiling range to catalytic hydrogen treatment under conditions designed to give high yields of good quality bright stocks.

The charge stock to our process may be any hydrocarbon lubricating oil stock. Thus we may treat distillate type lube oil stocks representing the lowest boiling portion of the lubricating oil range such as lubricating oils having a viscosity corresponding to spindle oil or 5W SAE. Our invention may also be applied with advantage to any intermediate boiling range distillate lube oil stock such as any lube oil corresponding to W SAE, SAE, 30 SAE etc. Our invention is also applicable to hydrocarbons of a heavier type such as those corresponding to bright stock. Bright stocks derived from residual portions of petroleum or distillates of the bright stock viscosity range produced by vacuum distillation may be used. When residual stocks are used as feed to the process they should be deasphalted.

A bright stock is frequently a component of lubricating oils, including those oils employed in the crank case of internal combustion engines. Such crank case lube oils are ordinarily produced by blending various components having different viscosities in order to obtain the diiferent SAE grades. For instance a 30 SAE crank case lube oil will frequently contain a certain amount of bright stock. The presence of this bright stock may in certain cases, have a deleterious effect because bright stocks are derived from the heaviest portions of the crude and these heavy portions ordinarily contain components having high carbon residue properties which result in poor performance during use. Our invention not only results in improvement in color, stability, etc., but it also results in a marked reduction in carbon residue. While carbon residue properties of bright stocks can be improved by conventional refining procedures, these procedures are so drastic that they eliminate a large portion of the bright stock as useful lubricating oil. Therefore the yields are low. Our invention not only yields lube oils and especially bright stocks having low carbon residues, but it gives such oils in unusually high yields as compared with prior art refining procedures.

The Eta alumina carrier can be prepared advantageously by dehydrating or calcining Bayerite 01' beta trihydrate of alumina. One such method for preparing Eta alumina is described by Stumpf et al., Industrial and Engineering Chemistry, Volume 42, page 1398 (1950). While this method for preparing Eta alumina is advantageously used, it is to be understood that any method for preparing Eta alumina is entirely satisfactory and may be used in accordance with our invention. Com mercial sources of Eta alumina are available and any such commercial Eta alumina may be employed in preparing a catalyst for use in accordance with our invention. The Eta alumina may contain other forms of alumina such as alpha, beta or gamma alumina. However the carrier should be predominantly Eta alumina and the higher the purity of the Eta alumina the better the action of the catalyst.

The hydrogenating component of the catalyst may be any hydrogenating metal, any hydrogenating metal oxide, any hydrogenating metal sulfide or any mixture of such hydrogenating catalysts. Thus the hydrogenatingcomponent may be platinum, tungsten oxide, molybdenum oxide, nickel, nickel oxide, etc. We prefer to employ a catalyst comprising a mixture of an oxide and/or sulfide of a group VI left-hand column metal with one or more oxides and/ or sulfides or an iron group metal. Thus this preferred catalyst may be a mixture of molybdenum and cobalt oxides or sulfides or a mixture of nickel and tungsten oxides or sulfides. The amount of hydrogenating component (determined as the metal) may be between about 0.25 and 30 wt. percent and preferably between about 15 and 25 weight percent. Such hydrogenating catalysts are well known in the prior art as well as their methods of preparation. Any of these prior art catalysts and any prior art method of preparation may be employed. Ordinarily it is preferable to form the Eta alumina carrier into tablets, pellets, etc. and to then impregnate this Eta alumina with aqueous solutions containing the salts of the metals to be used as a hydrogenation catalyst. Thereafter the catalyst is calcined to c nvert the active component into the oxide. If the sulfide is used, the catalyst is ordinarily presulfided such as by treatment with a mixture of hydrogen and hydrogen sulfide at elevated temperature. While we prefer to employ these particular prior art methods of preparation, any known method "for preparing hydrogenation catalysts deposited upon a carrier may be utilized.

The procedure of our invention is applicable to the treatment of the lubricating oil stock under reaction conditions which result in relatively little splitting of the lubricating oil charge stock into lower boiling hydrocarbons. In general these conditions involve the utilization of moderate temperature conditions such as between about 450 and 800 F. and preferably between about 500 and 780 F. The pressure is ordinarily between about and 5000 psi. and preferably between about 300 and 3500 p.s.i. A hydrogen recycle rate between about 100 and 10,000 s.c.f./bbl. and preferably between 3 about 500 and 5000 s.c.f./bbl. may be employed. A space velocity between about 0.2 and 16 volumes of charge per volume of catalyst per hour, and preferably between about 0.5 and 8 may be employed. As is well known in the hydrogenation field, the employment of low space velocities results in more extensive conversion at any given temperature. It is therefore evident that although the conditions described can in general be employed, the space velocity and temperature should be so selected that splitting into lower boiling hydrocarbons is not substantial.

EXAMPLE Eta alumina powder, manufactured by Davison Chemical Company, was tableted to form inch size tablets. These tablets were then broken to pass through a and to be retained on a 20 mesh sieve. The broken tablets were calcined by heating in air in an electric muffie furnace to 1000 F. in six hours and holding at this temperature for about ten hours. This calcined 10 to 20 mesh Eta alumina support (33.2 parts by weight) was impregnated by the incipient wetness technique With 410 parts by weight of an aqueous solution of nickel nitrate hexahydrate and ammonium metatungstate. This solution was prepared by using 177.2 parts by weight of 20 percent nickel nitrate solution (calculated as NiO) and 221.5 parts by weight of 49.5 percent ammonium metatungstate solution (calculated as W0 and diluting the mixture with 23.2 parts by weight Water. The mixture then contained 8.4 percent NiO and 26.1 percent W0 and had a specific gravity of 1.64. The wet impregnated material was dried at about 250 F. for 24 hours and calcined by heating in air in a muifle furnace to 1000 F. in six hours and holding this temperature for about ten hours. The finished catalyst contained 17.39 percent tungsten and 5.41 percent nickel. This catalyst was presulfided by contacting with H containing 10 volume percent H S at a temperature of 600 F. for a period of 8 hours. A lubricating oil stock prepared by propane deasphalting a residual fraction of an Ordovician crude followed by phenol extraction and solvent dewaxing and having a viscosity at 210 F. of 161 secs. SUV, a color- ASTM union of 4-(dilute) and a carbon residue of 0.88 (Conradson), was contacted with hydrogen in the presence of the above described catalyst under the conditions given in column 1 of the following table.

A second catalyst was prepared using as a carrier a commercial alumina which substantially comprised gamma alumina. This catalyst was prepared in the identical manner described above in connection with the catalyst on the Eta alumina carrier. Both catalysts had a nickel-to-tungsten molar ratio of 1:1. This second catalyst contained 17.16 percent tungsten and 5.34 by Weight nickel. This second catalyst was contacted with the same charge stock as used in column 1 and under the same conditions. The results are set forth in column 2 of the following table.

It will be noted from the above data that the catalyst deposited upon Eta alumina resulted in a consistently lower carbon residue than the commercial alumina carrier. The Eta alumina also resulted in greater improvement in color. Thus Eta alumina is a superior carrier for a catalyst used in this reaction.

The above example and especially column 2 thereof illustrates an additional specific embodiment of our invention. In general this specific embodiment involves utilization of any hydrogenation catalyst upon any porous catalyst carrier under specific reaction conditions which are designed to give a high yield of bright stock having a low carbon residue. Thus in accordance with this specific embodiment of our invention either a vacuum distillate or residual type bright stock feed is treated with any of the above described hydrogenation catalysts under conditions which are especially designed to give a superior bright stock product and in high yield. The hydrogenation catalyst employed in this specific embodiment of our invention is preferably deposited upon a porous catalyst carrier which, however, need not be Eta alumina. Thus for instance, the carrier may be activated gamma alumina, pumice, or other well known porous catalyst supports such as a silica-alumina cracking catalyst which has been deactivated with steam. The conditions employed to treat the bright stock feed and give these improved results are a temperature between about 500 and 775 F., a pressure between about 300 and 3500 p.s.i., a space velocity between about 0.25 and 2.0 and a hydrogen ratio of between about 300 and 5000 s.c.f. per barrel of charge.

The preparation of bright stocks using this last mentioned aspect of our invention is advantageously applied to residual type lubricating oil stocks. Such stocks should be deasphalted before the hydrogen treatment. While it is satisfactory to first solvent extract the deasphalted residual lubricating oil stock in order to remove aromatic constituents, utilizing known solvent extraction methods, it is advantageous to eliminate the solvent extraction step and directly subject the deasphalted residual lubricating oil stock to the hydrogen treatment. This has the ad vantage that aromatic components normally removed by the solvent extraction are left in the feed stock to the hydrogenation treatment. These aromatic components are then converted into high grade bright stock, thus increasing the yield. The pressure utilized in the treatment of a residual lubricating oil stock to obtain a high yield of refined residual type bright stock is preferably a pressure between about 2,000 and 3,500 p.s.i. The other reaction conditions of temperature, space velocity and hydrogen rate are the same as mentioned in the preceding paragraph in connection with bright stocks in general. When operating to produce bright stocks, whether of the residual or distillate type, we prefer to employ Eta alumina as a carrier. Also we prefer to employ a mixture of nickel and tungsten sulfides.

We claim:

1. The process for preparing an improved bright stock which comprises in combination contacting a deasphalted residual lube oil stock which contains about the same amount of aromatic hydrocarbons as the un-deasphalted stock with hydrogen in the presence of a hydrogenation catalyst deposited upon a carrier comprising essentially Eta alumina at a temperature between about 500 and 775 F., at a pressure above 2,000 and below about 3,500 p.s.i., at a space velocity of between about 0.25 and 2.0, and at a hydrogen rate of between about 300 and 5,000 s.c.f./bbl. of feed, said conditions resulting in avoidance of substantial splitting reactions and a high yield of refined bright stock having a relatively low carbon residue.

2. The process for preparing an improved bright stock which comprises in combination contacting a deasphalted residual lube oil stock which contains about the same amount of aromatic hydrocarbons as the un-deasphalted stock with hydrogen in the presence of a hydrogenation catalyst comprising essentially a mixture of nickel and tungsten sulfides composited with a porous support comprising essentially Eta alumina at a temperature between about 500 and 775 F., at a pressure above 2,000 and below about 3,500 p.s.i., at a space velocity of between about 0.25 and 2.0 and at a. hydrogen rate of between about 300 and 5,000 s.c.f./bbl. of feed, said conditions resulting in avoidance of substantial splitting reactions and a high yield of refined bright stock having a relatively low carbon residue.

References Cited in the file of this patent UNITED STATES PATENTS Kimberlin et al June 18, 1957 Riblett et al. Nov. 17, 1959 Holm et a1. Jan. 12, 1960 Annable et a1. May 10, 1960 Hofiman July 5, 1960

Claims (1)

1. THE PROCESS FOR PREPARING AN IMPROVED BRIGHT STOCK WHICH COMPRISES IN COMBINATION CONTACTING A DEASPHALTED RESIDUAL LUBE OI STOCK WHICH CONTAINS ABOUT THE SAME AMOUNT OF AROMATIC HYDROCARBONS AS THE UN-DEASPHALTED STOCK WITH HYDROGEN IN THE PRESENCE OF A HYDROGENATION CATALYST DEPOSITED UPON A CARRIER COMPRISING ESSENTIALLY ETA ALUMINA AT A TEMPERATURE BETWEEN ABOUT 500* AND 775*F., AT A PRESSURE ABOVE 2,000 AND BELOW ABOUT 3,500 P.S.I., AT A SPACE VELOCITY OF BETWEEN ABOUT 300 AND 5,000 AND AT A HYDROGEN RATE OF BETWEEN ABOUT 300 AND 5,000 S.C.F./BBL. OF FEED, SAID CONDITIONS RESULTING IN AVOIDANCE OF SUBSTANTIAL SPLITTING REACTIONS AND A HIGH YIELD OF REFINED BRIGHT STOCK HAVING A RELATIVELY LOW CARBON RESIDUE.