US2006092A - Process for production of lubricating oil - Google Patents

Description

June 25, 1935 U. B. BRAY ET AL PROCESS FOR PRODUCTION OF LUBRICATING' OIL Filed Aug. 4, 1951 BY ATTORNEY;

Patented June 25, 1935 UNl'lED .STATES PROCESS FOR PRODUCTION OF LUBBICATING OIL Ulric ana rams Verdes Estates, and Claude E. Swift, Huntington Park, Calif., assignors to Union: Oil Company of California, Los Angeles, Calif., a corporation of California Application August 4, 1931, Serial No. 555,010

27 Claim.

This invention relates to a method and apparatus for treating petroleum to produce lubricating oil. 7

One of the distinctive characteristics of a lubricating oil is its viscosity. For many purposes lubricants are preferred whiclr exhibita minimum variation in viscosity with variations in temperature, i. e., have low viscosity temperature susceptibility. It is generally known that the 10 viscosity of lubricating oil produced from Western crude, such as California naphthene base crudes, that is, crude containing asphalt varies more with change in temperature than do lubricating oils produced from parafiin base crudes. That is, if two such oils have the same viscosity at 100 F., the Western oil will have a muchlower viscosity at 210 F. than will the paraffin base oil. This change in viscosity with temperature is sometimes called the temperature susceptibility of an oil. It is one of the characteristics of Western lubricating oils that they are distillates that is, are vaporized from crude oil and condensed. Lubricating oils produced from parafiin base oils, containing substantially no asphalt, are generally produced by first distilling light oils overhead, including the kerosene and gas-oil and also taking overhead light lubricating oils called neutrals having a viscosity in the neighborhood of 100-200 seconds, Saybolt Universal at 100 F., leaving an undistilled residue termed bright stock. The oils of various viscosity are made by blending these neutrals and bright stockin any desired proportion to obtain the desired viscosity.

It has been observed by one of us that many oils containing asphalt and wax are mixtures of hydrocarbons analogous both to the hydrocarbons present in paraflin base oils and those present in asphalt base oils. It has further been observed by one of us that during the heating of an oil containing asphalt, the asphalt apparently induces certain chemical and perhaps certain physical reactions at relatively low temperatures which tend to destroy the inherent low viscosity temperature susceptibility of the lubricating oil fractions. This apparent catalytic phenomena seems to explain the observed changes although wedo not wish to be understood as being bound by this theory. It has been observed that these temperatures at which the changes appear are below the (vacuum or steam) of the lubricating oil fractions which have Saybolt Universal viscosities above 400-500 seconds at 100 F. It is safe to say that no oil containing asphalt can be topped to the point where fractions above 400-500 seconds,

vaporizer I05 is withdrawn through valve I02 Saybolt Universal viscosity at 100 F. are vaporv ized without a degeneration of those characteristics of the paraffin hydrocarbons which'impart to the oil a low temperature viscosity susceptibilty. During the distillation of the heavy oils in the presence of asphalt some change in molecular structure or configuration takes place which is attended by a change of viscosity temperature characteristics. This behavior is thought to be due to pyrolytic reactions which are catalyzed by 10 the presence of asphalt. The above discovery is made the subject matter of application Serial No. 466,189. a

In order to preserve the inherent characteristics of the lubricating oil components of crude 5 oil containing asphalt which are impaired by distillationmethods 'as previously' described, we have, in accordance with the process of the above application, caused the separation of the oil and wax from the asphalt by a method wherein the 20 lubricating oil constituents present in the crude oil are separated from the asphalt present in such a manner that the oil retains those characteristics which it possessed in the original crude 011., As a means of'attaining this end it has 25 been found advisable to cause the separation of the asphalt from the oil by means of solvents which are capable of dissolving the oil and which do not dissolve the asphalt. Such solvents are light petroleum fractions, such as naphtha, cas- 30 ingheadgasol'me and petroleum fractions normally vaporous at ordinary temperature and pressure. Other solvents which may be used are alcohol, ether, mixtures of alcohol and ether, acetone, etc. We prefer to use as our solvent a petroleum fraction obtained by the rectification of natural gasoline. For most purposes a fraction composed of 6.72% ethane, 72.2% propane, 19.91% isobutane and 1.17% normal butaneis satisfactory and is an example of com- 40 mercially obtainable propane. .-This fraction is characterized by an average molecular weight and an average vapor pressure substantially the molecular weight and vapor pressure of pure propane. It will be understood, however, that these merely illustrate the type of fractions which may be used and that the composition may vary. This fraction will hereinafter be referred to as propane for purposes of simplicity. It is obvious that pure propane or commercial propane, i. e., propane contaminated with methane, ethane, propylene, butane and the like, are equally applicable for use in our process.

In carrying out the extraction of the oil with this light liquid fraction the solution is maintained at a pressure sufilcient to maintain the propane liquid at ordinary temperatures. The fraction described above is liquid at ordinary temperatures at a pressure of about pounds per square inch. The extraction of'the oil from the petroleum at such pressures results in an asphalt substantially free of oil consisting chiefly of pure bitumen and a solution of oil and wax in the liquid petroleum fractions. The oil dissolved in the liquid propane contains substantially all of the lubricating oil components which are present in the crude oil and in substantially the same form as they exist in the original crude oil and also the major portion of the wax present in the crude oil.

We have discovered that many lubricating oils obtained by extraction with solvents, for instance, propane, from crude oil containing asphalt and wax are composed of oils which have a relatively high temperature viscosity susceptibility and oils which have a relatively. low temperature viscosity susceptibility and that these oils may be separated into oils which exhibit a low temperature viscosity susceptibility resembling oils produced from non-asphalt containing crude and oils which exhibit a high temperature viscosity susceptibility corresponding to oils produced by distillation. For. convenience we will call the oils which exhibit a low temperature viscosity susceptibility parafflnoid and those which exhibit a high temperature viscosity susceptibility and resemble the Western lubricating oil distillates non-paraifinoid. The propane extract which consists of such a mixture of parailinoid and non-parafilnoid oils may be separated into these respective oils by the use of solvent agents which will selectively dissolve out the non-parafflnoid components. We have found that certain solvents have a selective solvent action for the non-parafllnoid oils. As solvent agents which will effect this separation we have found liquid sulphur dioxide, mixtures of acetone and benzol, aniline or methyl formate useful. Acetone alone, in addition to being an asphalt precipitant, also has in some measure the ability to split the oil in the above manner. The use of liquid sulphur dioxide has been found especially valuable as a solvent to separate the propane extract into oils which exhibit low temperature viscosity susceptibility and into oils which exhibit high temperature viscosity susceptibility. As the propane extract from the crude oil consists of a mixture of wax and oil normally solid at ordinary temperatures, it cannot be separated into its parafilnoid and non-paraflinoid components by the use of sulphur dioxide, without considerable difliculty, unless dissolved in a carrying medium. We have found it advantageous to carry out the extraction of the wax oil mixture with sulphur dioxide in the presence of the liquid propane usedin separating the asphalt. The wax oil mixture is dissolved in liquid propane after which it is extracted with liquid sulphur dioxide to remove therefrom the non-paraflinoid components. The propane solution of. parafilnoid oil is then chilled to precipitate the wax present after whichthe chilled mass is cold settled, centrifuged, or filtered to separate the wax from the propane solution of oil. By removing the sulphur dioxide soluble bodies from the propane solution of waxy oil prior to the dewaxing operation we are able to obtain a final product with a lower pour point, i. 'e., .wax content than could be obtained if the sulphur dioxide extraction operation were performed subsequent to wax removal. The sulphur dioxide removes from oil certain bodies present which are good wax solvents and which have a tendency to prevent precipitation of the wax during the dewaxing operation.

The propane solution of oil recovered from the dewaxing operation substantially free of asphalt and wax may be further purified by treatment with sulphuric acid. Such treatment removes from the paramn oil further impurities which were not removed from the oil by the treatment with liquid sulphur dioxide.

Generally stated, it is the object of our invention to isolate from crude oil those oils having characteristics which impart, to it the low temperature viscosity susceptibility typical of paraffin base oil.

More particularly, it is an object of our invention to isolate from asphalt containing oils those components which impart to the oil the reduced susceptibility to change in viscosity with temperature which is characteristic of oils obtained from non-asphalt containing oils; that is, to separate the parafllnoid from the non-parafilnoid components of the asphalt containing crude oils.

It is a further object of our invention to separate asphalt from an oil containing asphalt, oil

and wax by means of a solvent, to separate the wax and parafiinoid oil from the non-parafllnoid oil by means of a second solvent used in the presence of the first solvent, to separate the wax from the parafiinoid oil and thereafter to treat the paraflinoid oil dissolved in said first solvent with sulphuric acid.

It is a further object of our invention to separate oil and wax from an oil containing asphalt, oil and wax by the use of liquid propane; to separate the wax and paraillnoid oil from the nonparafiinoid oil by the use of liquid sulphur dioxide in the presence of liquid propane; to separate the wax from the paraffinoid oil and thereafter to treat the parafllnoid oil with sulphuric acid.

Fig. 1 is one form of apparatus which we may employ to carry out our process.

Referring more particularly to Fig. l, the crude which has been distilled to remove light oils such as gasoline and kerosene and is itself a residual oil containing lubricating fractions, asphalt and wax in tank I is withdrawn through valve 2 and sent by means of pump 3 through line 4 where it meets a stream of liquid propane coming from tank i0 through valve ll, line l2, pump H5 and line l2. The mixture of topped crude and liquid propane passes from line 4 to chiller 5 where a portion of the propane is allowed to vaporize through valve 6 and passes by means of line I to pump 32 where it is compressed and sent to condenser 8 where it is liquefied and sent by means of line 9 to storage tank Ill. The vaporization of the propane in chiller 5 causes the temperature of the mass therein to be lowered. The cool mass' '22 where the asphalt separates from the vapors and is withdrawn through valve 23 and line" in the storage tank 25. The vapors in separator 22 are withdrawn through line 26 into condenser 21 where the water vapor present is condensed.

' The condensed water-and propane vapor pass into separator 28 where the water separates and is withdrawn through valve 29 and line 38. Propane vapor passes from separator 28 through line 8| to compressor lI3 -thence to condenser 8 where it is liquefied and passes by means of line 9 to storage tank I8.

The solution of oil in liquid propane in decanter I6 is withdrawn through line 33 and sent to chiller 84. A portion of the propane present is allowed to vaporize by opening valve 35 and allowing the vapors to pass through line 36 to compressor II8 where ibis compressed and sent to condenser 8 and is liquefiedl thereafter being sent to storage tank I8. The vaporization of the propane in chiller 34 cools the mass which is thereafter withdrawn through valve.3'I, line 38 and sent by means of pump 39 through line "to the lower zone of extraction column 4|. Liquid sulphur dioxide from tank 42 is withdrawn through valve 43 and sentby means of pump 44 through line 45 to the upper zone of extraction column 4I. Due to the difference in specific gravity of the oil introduced through the lower zone of the extraction column and the liquid sulphur dioxide introduced into the upper zone of the extraction column, these two liquids tend to separate. As the liquid sulphur dioxide descends through the extraction column it dissolves certain components present in the oil.

The solution of liquid sulphur dioxide and oil is removed from the extraction column 4I through the valve 46 and sent by means of line 41 to vaporizer I where the sulphur dioxide is vaporized by aid of steam introduced through closed coil WI and passes through line I86 to compressor I8I where it is compressed and sent through line I88 to condenser I89 where it is liquefied and sent to storage tank 42. Sulphur dioxide free oil in vaporizer I85 is withdrawn through valve I82 and sent through line I83 to tank I84.

The ascending column of oil in extraction column 4|, from which the liquid sulphur dioxide soluble components have been removed, passes through valve 48 to line 49 to auxiliary separator 58 where any remaining liquid sulphur dioxide is settled out. A clear solution of oil is withdrawn from auxiliary separator 58 through line 52 where it may be mixed with a further quantity of liquid propane coming from storage tank' I8 through valve 53, pump I I4 and line 54. The solution of oil and propane carrying a small quantity of sulphur dioxide passes into chiller 55 where a portion of propane is allowed to vaporize by opening valve M. The vaporized propane con-' taminated with sulphur dioxide, passes through line 62 to compressor I II where it is' compressed and sent through line 88 to condenser 89 where both the sulphur dioxide and the propane are condensed and pass by means of line I I8 to separator 98 where these two materials separate due to their great difference in specific gravity. The liquid propane in separator 98 is withdrawn through valve 9I and sent by means of pump 93 through line 96 to storage tank I8. The liquid sulphur dioxide in separator 98 is withdrawn through valve 92 and sent by means of pump 94 through line to storage tank 42. The vaporization of the propane in chiller 55 cools the remaining solution of oil present which passes out through valve 56 and line 51 to pump 58 which forces it through filter press 59 where the precipitated wax is removed through line 68.

The wax-free oil from filter press 59 passes through line 61 where it meets a stream of sulphuric acid coming from tank 63 through valve 64, line 65 and pump 66. The mixture of acid and oil passes from line 61 through agitator 68 where the mass is thoroughly agitated, after which it passes through line 69 to separator I8 where the sludge is allowed to settle out. The sludge in separator I8 is withdrawn through valve I5, line I6, to pump 11 which forces it through line I8 to heater I9 where the mass is heated sufficiently to vaporize the propane present. The heated mass passes from heater I9 through line 88 to separator M where the sludge separates from the propane and is withdrawn'through valve 82 and sent through line 83 to storage 84. The propane vapor is withdrawn from separator 8| through line 85 to compressor H 2 where it is compressed and sent by means of line 88 to condenser 89 where it is liquefied and sent by means of line II8 to separator 98 where it is separated from any liquid sulphur dioxide and sent by means of valve 9|, pump 93, line 96 to storage tank I8. The liquid sulphur dioxide in separator 98 is withdrawn through valve 92 and sent by pump 94 to sulphur dioxide storage tank 42.

The acid treated oil in separator'18, dissolvedin propane carrying varying amounts of sulphur dioxide, is withdrawn through line II and passed through clay tower I2 where any remaining sludge is separated out. 'The'fraction of oil leaving clay tower I2 passes by means of line I3 to evaporator 14 where the propane and sulphur dioxide present are vaporized by aid of steam introduced through closed coil 9! and are sent by means of line 86 to compressor 81 where they are compressed and sent by means of line 88 to condenser 89 where they are liquefied and sent by means of line I I 8 to separator 98. Liquid propane in separator 98 is returned to storage tank I8 through valve 9I, pump 93, and line 96. The sulphur dioxide in separator 98 is returned to storage tank 42 through valve 92, pump 94 and line 95. The oil in evaporator I4 which is free from propane and sulphur dioxide is removed through valve 98 and sent by means of line 99 to refined oil tank I88. 1

As illustrative of the operation of our process for one type of oil and without intending to limit our invention,-water free residual oil in tank I of Fig. 1 at a temperature of about 200 F. 15 mixed with liquid propane and cooled by allowing a portion of the propane to vaporize under reduced pressure until the temperature of the topped oil and propane is about F. after which it is thoroughly mixed in agitator I4. The thoroughly agitated mass is then passed into decanter I6 where the propane solution of lubrieating all and wax is separated from the undissolved asphalt. This oil dissolved in liquid propane contains a mixture of parafiinoid and non-paraiiinoid components. By subjecting this mixture to the selective solvent action of liquid sulphur dioxide in the presence of liquid.- propane it is possible to resolve the mixture into a portion of a non-paraflinoid nature soluble in liquid sulphur dioxide in the presence of liquid propane nature soluble in liquid propane. The wax present in the mixture being more soluble in the liquid propane than in the liquid sulphur dioxide remains in solution in the former. This mixture of paraflinoid oil and wax dissolved in liquid propane is then chilled to a point sufiicient to cause precipitation of the wax,- after which the chilled mass is filtered,- centrifuged or cold settled to remove the wax. The wax-free solution of paraffinoid oil dissolved in the liquid propane is then treated with sulphuric. acid to remove further undesirable bodies present, after which the sludge formed is settled out and the propane removed by distillation from the refined oil.

The foregoing exemplary description is merely illustrative of a preferred mode of carrying out our invention and is not to be taken as limiting, as many variations may be made within the scope of the following claims by a person skilled in the.

art without departing from the spirit thereof.

We claim:

1. A process for producing lubricating oil from oil which comprises dissolving said oil in a liquefled normally gaseous hydrocarbon, separating said oil dissolved in said liquefied normally gaseous hydrocarbon into a plurality of fractions with a selective solvent for non-parafilnoidhydrocarbons and. subsequently separating the liquefied normally gaseous hydrocarbon and solvent from said fractions.

2. A process for producing lubricating oil from oil which comprises dissolving said oil in a'liquefied normally gaseous hydrocarbon, separating said oil dissolved in the liquefied normally gaseous hydrocarbon with sulphur dioxide into a plurality of fractions and subsequently separating the liquefied normally gaseous hydrocarbon and sulphur dioxide from said fractions.

3. A process for producing lubricating 'oil from oil which comprises dissolving said oil in a liquefied normally gaseous hydrocarbon containing a major portion of hydrocarbons having less than four carbon atoms, separating said oil-dissolved in said solvent into a plurality of fractions with a selective solvent for non-parailinoid' fractions and subsequently separating the solvents from said fractions.

4. A process of selectively-extracting an oil into fractions which comprises commingling said oil with a liquefied normally gaseous hydrocarbon solvent, a major portion of which solvent consists of propane and a selective solvent for non-paraflinoid fractions of the oil, separating said oil into a plurality of fractions and separating said fractions.

5. A process of selectively extracting an oil into fractions which comprises commingling said oil with a liquefied normally gaseous hydrocarbon containing a major portion of propane and ethane and a sdective solvent for non-paraflinoid fractions of the oil, separating said oil into a plurality of fractions and separating said fractions.

6. A process of selectively extracting an oil into fractions which comprises commingling said oil with a hydrocarbon solvent at least as volatile as propane and a selective solvent for non-paraflinoid fractions of the oil, separating said oil into a plurality of fractions and separating sai fractions.

' 7. A process of selectively extracting an oil intofractions which comprises commingling said oil with a hydrocarbon solvent having an average molecular weight less than butane and a selective'solvent for non-parafiinoid fractions of the oil, separating said oil into a plurality of fractions and separating said fractions.

8. A process of selectively extracting an .oil into fractions which comprises commingling said oil with a hydrocarbon solvent having a vapor pressure greater than that of butane'and a selective solvent for non-paraflinoid fractions of the oil, separating said 011 into a plurality of fractions and separating said fractions.

9. A process for theseparation of oil into with a liquefied normally gaseous hydrocarbon and a selective solvent for non-,paramnoid fractions of the oil, cooling the mixture, separating a fraction dissolved in the selective solvent and removing the selective solvent and dissolved fraction from the mixture. I

10. A process as claimed in claim 9 in which the cooling is obtained by vaporizing a portion of the liquefied normally gaseous hydrocarbon from the mixture. 4

11. A process for the separation of oil into fractions which comprises commingling said all with a liquefied normally gaseous hydrocarbon diluent under superatmospheric pressure, releasing the pressure and vaporizing a portion of the diluent to chill the oil, extracting the cooled and diluted oil with a selective solvent for non-parafiinoid oil fractions, and separating the selective solvent and dissolved fractions from the oil.

12. A process as claimed in claim 11 in which the selective solvent is sulphur dioxide.

13. A'process for the separation of oil containing paraflinoid and non-paraifinoid components into fractions which comprises commingling said oil with a liquefied normally gaseous hydrocarbon and a selective solvent for-non-paraffinoid fractions of the oil, thereby forming a rafilnate phase comprisingparafiinoid oil dissolved in the liquefied normally gaseous hydrocarbon and an extract phase comprising non-parafllnoid oil dissolved in the selective solvent, separating said phases and recovering the oil from said phases.

14. A process for the treatment of lubricating oil containing parafiinoid and non-paraflinoid oils which comprises commingling said oil with a liquefied normally gaseous hydrocarbon and a selective solvent for non-parafilnoid oil, thereby forming a raflinate phase containing paraillnoid oil dissolved in the liquefied normally gaseous hydrocarbon and an extract phase containing non-parafiinoid oil dissolved in the selective solvent, separating said phases and recovering the 1 normally gaseous hydrocarbon and an extract.

phase comprising non-parafllnoid oil dissolved in the selective solvent and separating said phases.

16. A process for the treatment of oil containing asphalt which comprises commingling said oil with an asphalt precipitating solvent to dissolve the oil and precipitate the asphalt, separating the 4 precipitated asphalt from the solvent solution of oil, extracting the solvent solution of oil with a selective solvent for non-paraffinoid oil into a plurality of fractions and separating said fractions.

17. A process as claimed in claim 16 in which the asphalt. precipitating solvent is a liquefied normally gaseous hydrocarbon.

18. A process as claimed in claim 16 in which the asphalt precipitating solvent is a liquefied normally gaseous hydrocarbon containing v a major portion of propane.

19. A process as claimed in claim 16 in which the asphalt precipitating solvent is a liquefied normally gaseous hydrocarbon containing a major portion of hydrocarbons of less than four carbon atoms. I

20. A process for the treatment of an oil containing asphalt which comprises 'commingling said 011 with an asphalt precipitating solvent to precipitate the asphalt and to dissolve the oil, I

separating the asphalt from the solvent solution of oil, extracting the solvent solution of oil with a selective solvent for non-parafflnoid oil to form a fraction dissolved in said asphalt precipitating solvent and a fraction dissolved in said selective solvent, separating said fractions and treating the fraction dissolved in the asphalt precipitating solvent with sulphuric acid.

21. A process as claimed in claim 20 in which the asphalt precipitating solvent is a liquefied normally gaseous hydrocarbon.

22. A process as claimed in claim 20 in which the asphalt precipitating solvent is a liquefied normally gaseous hydrocarbon and the selective solvent is liquid sulphur dioxide.

23. A process as claimed in claim 20 in which the acid treated oil is treated with clay.

24. A process for the treatment of oil containing asphalt which comprises commingling said oil with a liquefied normally gaseous hydrocarbon diluent to dissolve the oil and precipitate the asphalt, removing the asphalt from the oil dissolved in said diluent, extracting the oil dissolved in said diluent with a selective solvent for non-paraiilnoid oil to form a traction dissolved in said selective solvent and a fraction dissolved in said diluent, separating said fractions, treating said fraction dissolved in said diluent with sulphuric acid and treating the acid treated oil with clay.

25. A process as claimed in claim 24 in which the liquefied normally gaseous hydrocarbon contains a major portion of propane.

26. A process as claimed in claim 16 in which the selective solvent is sulphur dioxide.

27. A process as claimed in claim 16 in which the asphalt precipitating solvent is a liquefied normally gaseous hydrocarbon and the, selective solvent is sulphur dioxide.

- ULRIC B. BRAY.

CLAUDE E. SWIFT.

crnrmjcare 0F CORRECTION.

Patent No. 2,005,092. June 25. 1935.

ULRIC B. BRAY, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring'correction as follows: Page 1, first column, line 50. forthe words "vaporizcr 105 is withdrawn through valve 102" read vaporizing temperatures in batch distillation; and page 3, second'column, line 65 for the words "in the presence of liquid propane" read and a portion of a paraffinoid; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 19th day of .Novemher, A. D. 1935.

Leslie Frazer (Seal) Acting Commissioner of Patents.

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