US2097245A - Lubricating oil - Google Patents

Description

Oct. 26, 1937. c. c. TowNE 2,097,245

LUBRIQATING OIL Filed March '7, 1934 h s, Zar/es Q'W//e INVENTOR ,5f/s ATTORNEY Patented Oct. 26, 1937 2,097,245 vUUBRICATING OIL Charles C. Towne, Poughkeepsie, N. Y., assignor to The Texas Company, New York, N. Y., a corporation of Delaware Application March 7, 1934, Serial No. 714,360

This invention relates to the manufacture of petroleum lubricating oils, and particularly oils of this character possessing a green uoresc'ence and other desirable properties.

One of the objects of this invention is to provide a petroleum lubricating oil possessing a green fluorescence froma. distillate oil ,which is normally decient in that property, by utilization of cheap or normally waste materials available at oil reiineries, such as iixed refinery gases or oil gas from cracking stills.

depressant. i

Still another object of the invention is to provide. a method of dewaxing a wax bearing oil by the employment of a wax crystal modifying material obtained from gaseous hydrocarbons of this character.

It is well known that certain distillate lubricating oils, which are of excellent quality as lubricants, are nevertheless deficient in the property of bloom. Certain Pennsylvania lubricating oils are reddish-brown by transmitted light and green by reflected light, thereby possessing what is termed a green bloomor fluorescence. In certain instances, it has been considered desirable to impart to lubricating'oildistlllates which are deficient in this property of bloom, a green iiuorescence similar to that which is characteristic of Pennsylvania base oils. It has heretofore been suggested that a green bloom imparting material can be prepared fromthe residuum of distillation, either cracking or non-cracking, of a petroleum However, this has necessitated the employment, as starting materials, of mineral oils which could otherwise be used for the preparation of Furthermore, this has necessitated special distillation equipment and processing, in order to produce a bloom impartoil.

more valuable products.

ing material of acceptable character.

14 Claims. (Cl. 196--10) propane, butane, etc., and mixtures thereof, may be employed for this purpose.

According to the present invention, the hydrocarbon gases are subjected to high temperature pyrolysis in a cracking still. This may be accomplished in connection with aplant for the manufacture of benzol and its homologues from hydrocarbon gases by pyrolysis thereof, in accordance with my Patent No. 1,943,246 dated January 9, 1934, High temperature pyrolysis has the usual 10 significance of this term in the art,-namely, a pyrolysis in which the gases are passed through a heating coil or `zone at a temperature in excess of 1150 F., and generally at temperatures varying between 11502000 F. Known types of cat- 15 alysts may be employed, either as porous catalysts within the heating tubes, or as materials constituting the heating tubes. The gases may be maintained at substantially atmospheric pressure, or they may be passed through the heating 20 coil under superatmospheric pressures varying up to 500 lbs. per sq. in. or higher. The pyrolyzed gases are then passed to a cooling zone, such as awater cooled condenser, where the temperature is controlled to separate primarily high boiling 25 constituents, mainly above the boiling points of benzol and homologous hydrocarbons of the benzene series. In this manner, there is condenseda liquid fraction comprising a heavy black oil.; Depending upon the temperature of condensa-s@ tion, this material will usually comprise a small;A .Tf proportion of benzol and naphthalene in admix-l ture with a tarry residue. The latter is found to be highly concentrated in green bloom imparting material. The condensate oil may be mixed directly with a mineral lubricating oil to impart a green fluorescence thereto; or a concentrated extract of bloom imparting material may be obtained from the condensate oil by suitable methods, such as distillation or solvent extraction, and the concentrated extract then added to a mineral lubricating oil.

Referring tothe drawing, in which the single figure is'a diagrammatic View of apparatus for carrying out the method of this invention, IIJ indicates a cracking furnace containing a coil II through which the hydrocarbon gas is passed and heated to a high temperature such as ordinarily used in gas pyrolysis operations. The products of pyrolysis are discharged into a water cooled condenser I2, to which cooling water is supplied by line I3 and discharged by line I4.

- The products pass upwardly through tubes I5 of the condenser, uncondensed gases escaping by pipe I6 leading to a fractionating tower I1 where various lower boiling constituents, including benzol, may be separated. 'I'he gas outlet temperature of the condenser I2 is preferably controlled to about 400 F. or above, so that mainly high boiling constituents are condensed therein. These constituents form a black oil which runs down the tubes i5, accumulating in the lower portion of the condenser, and discharging by the line 20. Although normally solid compounds are present in this oil, the liquid constituents maintain them in solution, and clogging of the condenser does not occur.

This condensed oil may be added directly to a mineral lubricating oil to impart a green bloom to the latter. Or, if desired, the condensed oil may be treated or purified prior to use, such as by simple filtration, or by heating in contact with an adsorbent material followed by filtration, or by acid treatment or other conventional treatments employed in the refining of petroleum oils. This is indicatedin the drawing, in which the pipe 20 discharges into a refining tank 2| to which suitable chemical may be introduced by pipe 22. If desired, the oil may be treated to prepare a concentrate therefrom; as it is found that the bloom imparting materials in the oil consist mainly of high boiling constituents which remain in the tarry residue resulting from reducing the oil by distillation, or are dissolved from the voil or residue by solvent extraction. However, it is not necessary that any of these reiining or concentrating treatments be employed, as the condensate recovered from condenser I2 may be satisfactorily marketed as a bloom imparting material. l

The condensate, whether treated or not in the refining tank 2l, is passed by line 24 to either valve controlled'line 25 leading to receiver 26, or valve controlled line 2`| leading to receiver 28. From the receivers 26 and 28, the bloom oil or concentrate is passed by lines 29 and 30 respectively to a blending tank 32, to which the lubricating oil to be treated is admitted by line 33. Only a small proportion of the bloom oil or concentrate need be added to a mineral lubricating oil to impart a satisfactory green fluorescence thereto. Thus, less than 2% by weight of the condensate as obtained from condenser I2, or even a smaller proportionof extract. prepared therefrom, is ordinarily employed in blending with a distillate lubricating oil. The blended oil is then passed by line 36 to storage tank 36, from which it is withdrawn for use or further treatment by line 31.

As a specific example of the present invention,

an oil gas obtained from vapor phase cracking stills, is passed through a silica tube 20 mm. in diameter by 48 in. in length at the rate of 0.6 cu. ft. per hour, the tube being maintained at a temperature of 14501500 F. Issuing vapors are cooled in a water cooled condenser having a vapor outlet temperature of approximately 450 F. A black condensate oil is thereby obtained in the amount of approximately 10 cc. per 4 to 5 cu. ft. of gas treated. 0.25 cc. of this oil dissolved in cc. of a pale Mid-Continent distillate lubricating oil (Saybolt viscosity 300 at 100 F.) so altered the appearance and bloom of the distillate oil that vit resembled a natural parailin base cylinder stock.

It has further been found that the shade of the bloom imparted to pale lubricating oils by the product of this invention varies with the temperature at which the latter is prepared. For example, where an oil gas from a vapor phase cracking still is pyrolyzed at a temperature of approximately 14501500 F., and a condensate oil recovered therefrom in the manner described above, the green bloom imparted to a mineral distillate oil is found to possess a slight bluish tinge. On the other hand, where the same oil gas is passed through the same cracking still at a temperature ofapproximately 16001700 F., the condensate oil recovered therefrom, when added to the same pale lubricating oil, imparts a green bloom which has .a somewhat yellower tinge than that of a usual Pennsylvania oil. By blending in suitable proportions theA condensate oils prepared at different temperatures, and adding the blend to a distillate oil, a resulting bloom is obtained which approaches very closely the green bloom of a customary Pennsylvania oil, while at the same time the reddish-brown color by transmitted light is substantially the same. 'I'he heat treatments at different temperatures may be accomplished in separate cracking stills. Or, as shown, a single cracking still may be employed; and a certain proportion of oil gas passed through the furnace I0 at one temperature, the

condensate oil being collected in one of the receivers 26 or 28, and then another portion of oil gas passed through the cracking furnace Il at a different temperature, the condensate oil therefrom being collected in the otherreceiver. The resulting bloom oils may then be blended in the blending tank 32 by introduction in controlled proportions through lines 29 and 30 from the rel.ceivers 26 and 28 respectively.

The products of the present invention as described above are also useful as pour point depressants for lowering the pour point of a mineral oil. For example, the addition of a small proportion of a heavy condensation product recovered from the high temperature pyrolysis of a normally gaseous hydrocarbon of the character described above, to a partially dewaxed lubricating oil derived from a paraffin base or a mixed base crude, will materially lower the normal pour point of such lubricating oil. It is recognised that the presence of a certain amount of wax in a paraffin base or mixed base lubricating oil may be beneficial from the standpoint of providing a comparatively flat temperature-viscosity curve. However, the pour point of such a partially dewaxed lubricating oil of this character is normally high, such as. around 25 F. or above. Consequently, it is of advantage to add to the oil a material which will have the eect of reducing the pour test or cold test to the desired extent without the necessity of entirely removing the remaining wax. .The condensation product produced as outlined above may be added directly to a lubricating stock; or an extract of the condensation product may be first prepared and this extract added to fthe lubricating stock. Thus, a small proportion of the mineral oil to be treated, or other lubricating oil, may be used to form a concentrate of the active pour point depressant materials in the condensation product; and this concentrate can then be added in predetermined proportions to a larger body of the oil to be treated. Again, different solvents may be employed to produce an extract of the condensation product. Suitable solvents include benzene,

' xylene, toluene and various aliphatic monohydric alcohols from methyl to the amyl alcohols. The proportions in which the pour point depressant material is added to the mineral lubricating oil can be Ivaried widely. However, it il usually desirable to add only that proportion tion with the wax crystal modifying material and? which will lower the pour point to the required low temperature. Generally, less than by weight of the pour point depressant material is used; and often as little as a fraction of 1%, such as about 1/2 or less, is sufficient.

The products of the present invention are also useful in connection with the removal of wax from a Wax bearing hydrocarbon oil. Thus, the addition of a small proportion of the heavy condensate, or extracts thereof, recovered from the high temperature pyrolysis of a normally gaseous hydrocarbon of the character set out above, to a Wax bearing oil, is found to modify wax crystal formation upon chilling of the oil, to thereby facilitate separation of the wax from the oil by centrifuging or cold settling. It is also found that the addition of a wax crystal modifying material of this character to a. wax bearing oil results in substantially increasing filtering rates, where the wax is separated from the chilled oil by filtration. The employment of products of the present invention along with a solvent in which both the solid and normally liquid constituents are soluble at elevated temperatures of the order of 100 F. or above, and in which the normally liquid constituents are soluble but the normally solid constituents or waxes are substantially completely insoluble at lowered temperatures of the order of 0 F. t0 -20 F., is found particularly beneficial. Various solvents of this character may be employed, such for example, as acetone, ethylene dichloride, methyl ethyl ketone, liquid sulphur dioxide, naphtha, propyl alcohol and the like. Mixtures of such selective and non-selective solvent liquids are also satisfactory. For example, a very suitable solvent mixture capable of serving as a dewaxing solvent consists of acetone and benzol, for instance in the proportions of 35% acetone and 65% benzol. Another very'suitable solvent mixture, particularly for the dewaxing of residual oils, consists of about 28-35% acetone, 47-5'7% benzol and 15-18% toluol. v

By way of example, a proportion of from l to by weight of the heavy condensation product obtained from the pyrolysis of oil gas, as described above, may be added to a Wax bearing lubricating oil fraction, together with a solvent mixture of 35% acetone and 65% of benzol in the proportions of one part of oil to three parts of the acetone-benzol mixture. The oil is then chilled to a temperature of around 0 to 10 F. and subjected to settling at this temperature. The wax constituents settle rapidly from the mixture, the supernatant liquid layer of oil and solvent may be drawn off, and the solvent removed therefrom by distillation. According to another method of operation, the chilled mixture may be subjected to centrifuging with satisfactory separation of the wax from the oil. In still another method of operation, the chilled mixture may be subjected to dewaxing by pressure filtra.- tion, and the filtering rates be markedly increased over the rates obtained when the condensation product of the present invention is not added. Where a solvent mixture of the charac- This is found beneficial when used in conjuncalso with the solvent or solventmixture.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may' 1. A lubricating oil possessing a green 11u0- rescence, comprising a mixture of a petroleum lubricating oil with a minor proportion of a heavy condensate recovered from the high temperature pyrolysis of a normally gaseous hydrocarbon.

2. A lubricating oil possessing a green uorescence, comprising a mixture of a petroleum lubricating oil with a minor proportion of a heavy condensate recovered from the high temperature pyrolysis of fixed gases from a cracking still.

3. A lubricating oil possessing a green fluorescence, comprising a mixture of a petroleum lubricating oil with a minor proportion 0f a heavy condensate recovered from the high temperature pyrolysis of natural gas.

4. A lubricating oil possessing a green liucrescence, comprising a mixture of a petroleum lubricating oil with a minor proportion of a heavy condensate recovered from the high temperature pyrolysis of oil refinery waste gases.

5.v A lubricating oil possessing a. green uorescence, comprising a mixture of a petroleum lubricating oil normally deficient in bloom, with an'amount up to 2% byv weight of a heavy condensate formed by pyrolysis at temperatures in excess of 1150 F. of a normally gaseous hydrocarbon suiiicientvto impart the said green fluorescence to the lubricating oil.

6. A lubricating oil possessing a green fluorescence, comprising a mixture of a petroleum lubricating oil with a minor proportion of a blend of heavy condensates formed by high temperature pyrolysis of a normally gaseous hydrocarbon, one condensate of the blend being formed by pyrolysis at a diiierent temperature from that of another condensate to thereby give a resultingy blend of a controlled color and bloom.

7. A lubricating oil possessing a green fluoresence, comprising a mixture of a petroleum distillate lubricating oil which is normally deficient in bloom, with an amount up to 2% by weight of a heavy condensate oil recovered from the pyrolysis of oil gas at temperatures of l4501700 F., sufdcient to impart the said green fluorescence to the lubricating oil.

8. A lubricating oil possessing a green fluorescence, comprising a mixture of petroleum distillate lubricating oil, with an amount up to 2% by weight of a blend of heavy condensate oils formed by high temperature pyrolysis of oil gas sufficient to impart the said green fluorescence to the lubricating oil, one condensate oil resulting from pyrolysis at a temperature of 1450"- 1500 F., and another condensate oil resulting from pyrolysis at a temperature of 16001700 F.

9. The method of producing a green bloom lubricating oil, which comprises passing a normally gaseous hydrocarbon through a heating zone maintained at a temperature in excess of 1150 F. to pyrolyze the gas, cooling the pyrolyzed gas to recover therefrom a heavy condensate which is concentrated in green bloom imparting material, and adding a proportion of the heavy condensate to a petroleum lubricating oil.

10. 'I'he method of producing a green bloom lubricating oil, which comprises passing one por- 76 tion of a normally gaseous hydrocarbon through a heating zone maintained at a temperature in excess of 1150 F. to pyrolyze the gas, passing another portion of a normally gaseous hydrocarbon through a heating zone maintained at a diilerent,

temperature but also in excess of 1150 F.'to pyrolvze the gas, cooling the pyrolyzed gases to recover therefrom heavy condensates which are concentrated in green bloom imparting materials, and adding the condensates in controlled proportions to a petroleum lubricating oil to importions of each of the heavy condensates with a petroleum distillate lubricating oil which ls normally deficient in the property o! bloom to lmpart to the latter a green bloom of controlled shade.

12. A lubricating oil having a low pour point, comprising a mixture of a partially dewaxed lubricating oil normally having a higher pour point with a small proportion of a heavy condensate recovered from the high temperature pyrolysis of a normally gaseous hydrocarbon.

13. A lubricating oil of improved character comprising a mixture of a petroleum lubricating oil with a minor proportion of a heavy condensate boiling essentially above 400 F. recovered from the high temperature pyrolysis of a normally gaseous hydrocarbon.

14. A lubricating oil possessing a green fluorescence, comprising a mixture of a petroleum lubricating oil with a minor proportion o! a heavy condensate recovered from the high temperature pyrolysis of a normally gaseous unsaturated hydrocarbon.

' CHARLES C. TOWNE.

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