US2040057A - Manufacture of lubricating oil - Google Patents

Description

Patented May 5, 1936 UNITED STATES PATENT, OFFICE 2,040,057 MANUFACTURE OF LUBRICATING OIL No Drawing. Application February 25, 1933. Serial No. 658,668

16 Claims.

This invention relates to the manufacture of lubricating oil characterized by a low pour test and having other desirable qualities including a desired green fluorescence.

The invention contemplates the preparation of mineral lubricating oil having'a reduced pour test and other desired qualities from lubricating oil stocks, such as those derived from mixed base crudes and the like, by the addition to the lubricating oil of a pour-depressing material or wax crystal inhibitor. The invention particularly contemplates the preparation of a suitable pour-1 depressing material from pitch formed. by subjecting carbonaceous bodies, such as the tarry residua resulting from the cracking of mineral oil, or the extracts resulting from the solvent refining of mineral oil, to destructive heating or cracking, thereby producing a pitch containing constituents having the desired pour-depressing and coloring characteristics. This pitch is then treated with a solvent for the purpose of extracting these desired. constituents, following which they may be added to the lubricating oil stock which is to be treated.

As a solvent extracting medium, the lubricating oil stock itself, or a portion thereof, may be used, in which case it may be of advantage to carry out the solvent extraction step in the presence of a comminuted solid catalytic material to facilitate the removal of undesired impurities.

Any solvent suitable for the purpose may be employed and may comprise solvents selected from the aliphatic or aromatic hydrocarbons, or the cyclic hydrocarbons of the furan type. Such solvents might, therefore, include light petroleum fractions, aliphatic ketones, benzol, furfural, or mixtures of these solvents with each other or with other liquids, to produce mixtures adapted to extract the desired constituents from the pitch.

advantageous feature of the pour-depressing material of our invention resides in its ability to impart a desired green fluorescent color to lubricating oil stocks derived from certain crude sources, and which are normally deficient in this respect. This desired green fluorescence is characterized by the oil having a red color when viewed by transmitted light, and a green color when viewed by reflected light, and which characteristics have become associated with certain grades of lubricating oils. a

Lubricating oil stocks derived from parafiin and mixed base crudes contain substantial amounts of wax and, therefore, have a relatively high pour test unless a substantial amount of this wax is removed. The removal of this wax is usually accomplished by cold settling, filtration, or centrifuging. However, lubricating oil stocks, after dewaxing by these processes, may still retain a substantial amount of wax and, therefore, may have a pour test well above 0'F.' The removal of further quantities of wax from these stocks in order to further reduce the pour test necessitates further processing.

On the other hand, the presenceof a certain amount of wax in lubricating oils may be beneficial from the standpoint of producing a lubricating oil having a suitable temperature-viscosity characteristic. Consequently, it is of advantage to add to the oil a material which will have the effect of reducing the pour test or cold test to the desired extent without the necessity of entirely removing the remaining wax.

The material of our invention is simply and readily prepared from oil refinery waste materials by the employment of a procedure comprising treating steps which are more or less similar to those used in ordinary petroleum refining operations.

Waste materials suitable for use in preparing the pour-depressing material of our invention advantageously comprise cracked petroleum tar, sometimes referred to as pressure-tar, resulting from the liquid or vapor-phase cracking of mineral oil for the productionof motor fuels. Other suitable materials may comprise the extract material separated from petroleum fractions, particularly lubricating oil fractions, during the refining of such fractions with solvents such as furfural, liquid sulphur dioxide, and the like. The polymerized material removed from cracked naphtha by treatment with a catalytic adsorbent clay may also be utilized. i

We have found that the pour-depressing material produced from these sources in accordance with the procedure of our invention possesses, in addition to its wax crystal inhibiting properties, the ability to impart a desired green fluorescence to lubricating oils which are normally deficient in this respect.

The preparation of fluorescent bodies and their beneficial efl'ect .when added to lubricating oil fractions is known in the prior art, but such materials heretofore have been prepared from coal tar products or residues which are known to be rich in aromatic bodies or constituents of the desired character.

The raw materials, or oil refinery waste materials from which our product is prepared, do not, in their original condition, contain the desired constituents to any appreciable extent. If presing oil stock in the proportion of about 4 to 10 ent to any appreciable extent, they are at least not readily recoverable from these waste materials by usual extraction procedures.

We have found, however, that by-subjecting these refinery waste materials to substantial cracking whereby a high melting point pitch is formed, representing about 50% or 60% of the charge, such pitch contains these desired bodies in substantial amount.

The preparation of these bodies from such waste carbonaceous materials and their addition to lubricating oilstocks will now be described in more detail. a

The waste carbonaceous bodies, such as a cracked petroleum tar, or a solvent extract obtained from the solvent refining of mineral oil, is subjected to cracking at temperatures of about 850 to around 1000 F. and under pressures which may range from substantially above atmospheric to 400 pounds or higher. The particular-temperatures and pressures employed, as well as the duration of the time to w ch the material is subjected to cracking conditions, will depend upon the nature of the material, but may advantageously be adjusted or regulated so as to convert the charge into a residue, comprising, for example, about 60% of the charge. This residue, which is in the nature of a pitch, solid at room temperature and having a ball and ring melting point of around 160 to 180 F., contains the desired pour-depressing bodies. This pitch from recracked pressure tar or cracked extraction products of the character described is found to be primarily insoluble in mineral lubricating oil, but contains desirable oil-soluble pour depressant constituents in concentrated form. The pitch is particularly free from objectionable oil-soluble material which imparts a darkening effect to pale lubricating oils.

This pitch, while maintained in a fluid condition, as, for example, by heating to 200 or 250 4 F., is mixed with, or dissolved in, a suitable sol-- vent. The solvent advantageously comprisesv a portion of the lubricating oil stock to which the final pour-depressing and fluorescent material is to be added. It may be mixed with this solvent mineral oil fraction in proportions varying from 5 to 50 volumes of pitch to 100 volumes of oil.

To this mixture, a solid adsorbent catalytic material is added, ranging from about 10 pounds to 45 pounds per barrel of mixture. The catalytic material may comprise a diatomaceous earth or fullers earth, or may consist of an acid-treated clay.

The mixture of oil and clay is then heated to temperatures of around 350 to 400 F. in the presence of steam, if desired, and filtered while hot. The catalytic material, during this preceding operation, is believed to exert a polymerizing effect upon the undesired constituents of the extracted material, and which polymerized constituents are removed along with the clay in the form of a filter cake during the filtering operation.

The resulting filtrate contains the desired extracted bodies which, when added to the lubricating oil stock, substantially depress the pour test of the oil as well as impart thereto the desired color characteristics. This filtrate, containing the extract, may then be added to the lubricatparts of filtrate to about 96 to parts of'lubrieating oil stock and the whole subjected to mixing.

For example, the ad tion of about '6 parts of this filtrate to 94--parts ofa lubricating oil fraction derived from mixed base crude, having a Saybolt universal viscosity of around 300 seconds at F. and a pour test of 25 F., reduces the pour test to around 0 F.

While certain temperature and pressure conditions aswell as liquid proportions have been set for h in the foregoing example, the invention is not restricted to these particular conditions since they may be varied as desired, depending upon the lowed by contacting with clay. It is contemplat-' ed, however, that the high melting point pitch from which the pour-depressing materials are to be extracted may be added directly to the main body of lubricating oil stock before this stock has been subjected to contact filtration in the presence of clay. In this way, only a single contact filtration'operation with clay will be necessary.

As already indicated, the pour-depressing and fluorescent bodies dissolved from the high melting point pitch may be separated from the solvent in which they are dissolved in order to .produce them in substantially concentrated form. This desired, may be selectiveiy extracted with solvents of differing solvent concentrated material, if

capacity, or with relatively light or volatile solvents in order to segregate the material into fractions, some of which may be segregated in a substantially dry or powdery form. It has been found that the material in this latter form may also be added to lubricating oil stocks with equal effect.

Reference to cracked petroleum tar" in the appended claims includes tarry residues formed during the usual liquid or vapor-phase cracking The term extraction products is intended to include extracted materials and polymerized odies,

tion withvarious solvent liquids, 'or by contacting these fractions with catalytic or other treating agents.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. In the process of manufacturing mineral lubricating oil from lubricating oil stock containing parafiin wax and deficient with respect to color characteristics, the method of reducing the pour test of the oil and imparting thereto a defluorescence which comprises substantially cracking at high temperature and under superatmospheric pressure an oil refinery residue selected from the group consisting of cracked petroleum tar, extraction products separated in the solvent refining of petroleum fracoil-soluble material from the pitch in a portion of the lubricating oil stock to be treated, mixing of mineral oil for the production of motor fuel.

as already indicated, which are removed therewith acomminuted solidadsorbent catalytic material, filtering the mixture to produce a filtrate containing hydrocarbon bodies extracted 4 from the pitch which have the desired pour-depressing and fluorescent characteristics and are free from undesirable constituents, and mixing said filtrate with the main body of lubricating oil stock to produce a lubricating oil of desired characteristics.

2. In the process of manufacturing mineral lubricating oil from lubricating oil stock containing paraflin wax and deficient with respect to color characteristics, the method of reducing the pour test of the oil and imparting thereto the desired green fluorescence which comprises subjecting an oil refinery residue selected from the group consisting of cracked petroleum tar, extraction products separated in the solvent refining of petroleum fractions, and extraction products separated from adsorbent filters in the refining of petroleum fractions to substantial cracking at .a temperature of from about 800 F. to around 1000 F. and under superatmospheric pressure to produce a high melting point pitch which is pri marily insoluble in mineral lubricating oil but contains oil-soluble constituents having the desired pour-depressing 'and coloring characteristics, dissolving oil-soluble constituents from the pitch in the lubricating oil stock to be treated, mixing therewith a comminuted solid adsorbent catalytic material, heating the resulting mixture and filtering while hot to produce a filtrate comprising lubricating oil having the desired cold test and fluorescent characteristics and free from undesirable constituents.

3. In the process of manufacturing mineral lubricating oil from lubricating oil stock containing paraffin wax and deficient with respect to color characteristics, the method of reducing the pour test of the oil and imparting thereto the desired green fluorescence which comprises subjecting an oil refinery residue selected from the group consisting of cracked petroleum tar, extraction products separated in the solvent refining of petroleum fractions, and extraction products separated from adsorbent filters in the refining of petroleum fractions to substantial cracking at teifier'atures of from about 800 F. to around 1000" F. and under superatmospheric pressure to thereby produce a pitch which is priniarily insoluble in mineral lubricating oil but contains oil-soluble constituents having the desired pour-depressing and coloring character-' istics, dissolvingoil-soluble constituents from the pitch in a portion of the lubricating 011 stock to be treated, mixing therewith'a comminuted acidtreated clay, heating the mixture in the presence of steam to an elevated temperature not substantially exceeding 400 F., filtering while hot to produce a filtrate containing hydrocarbon bodies having the desired characteristics and free from undesirable constituents, and mixing said filtrate with the main body of lubricating oil stock to produce a lubricating oil of desired characteristics.

4. The method of preparing a material adapted to reduce the pour test of mineral lubricating oils and to impart thereto a desired green fluorescence, which comprises subjecting an oil refinery residue selected from the group consisting of cracked petroleum tar, extraction products separated in the solvent refining of petroleum fractions, and extraction products separated fromadsorbent filters in the refining of petroleum fractions, to substantial cracking at high temperature and under superatmospheric pressureto form a pitchy residue which is primarily insoluble in mineral lubricating oil but contains oil-soluble constituents having the desired pour-depressing and coloring characteristics, and separating said constituents from the pitch by extraction with a solvent.

5, The method of pr paring a material adapted to reduce the pour test of mineral lubricating oils and to impart thereto a desired green fluorescence, which comprises subjecting an oil refinery residue selected from the group consisting of cracked petroleum tar, extraction products separated in the solvent refining of petroleum fractions, and extraction products separated from adsorbent filters in the refining of petroleum fractions, to substantial cracking at high temperature and under superatmospheric pressure to form a high melting point pitch solid at ordinary temperatures, 'which is primarily insoluble in mineral lubricating oil but contains oilsoluble constituents having the desired pour-depressing and coloring characteristics, mixing a mineral oil fraction with said pitch adapted to extract said constituents therefrom, heating the resulting mixture to effect extraction, and removing the solvent liquid therefrom to produce the desired material in concentrated form 6. The method of preparing a material adapted to reduce the pour test of mineral lubricating oils and to impart thereto a desired green fiuorescence, which comprises subjecting an oil refinery residue selected from the group consisting of cracked petroleum tar, extraction products separated in the solvent refining of petroleum fractions, and extraction products separated from adsorbent filters in the refining of petroleum fractions, to substantial cracking at high temperature and under superatmospheric pressure to form a pitchy residue which is primarily insoluble in mineral lubricating oil but contains oil-soluble constituents having the desired pourdepressing and coloring characteristics, mixing a'lubricating fraction of mineral oil with said residue and commingling therewith a comminuted acid-treated clay, heating the resulting mixture and filtering while hot to'remove undesired impurities and produce a filtratecontaining the desired material dissolved in the oil.

7. The method of preparing a material adapted to reduce the pour test of mineral lubricating oils and to impart thereto a desired green fiuo rescence, which comprises subjecting an oil refinery residue selected from the group consistand filtering while hot to remove undesired impurities and produce a filtrate containing the desired material dissolved in the oil.

8. The method of producing a pom point reducing agent for a mineral lubricating oil, which comprises subjecting an oil refinery residue selected from the group consisting of cracked petroleum tar, extraction products separated in the solvent refining of petroleum fractions, and

, extraction products separated from adsorbent filters in the refining of petroleum fractions, to substantial cracking at high temperature and under superatmosphe'ric pressure..to reduce the material to a pitch substantially solid at atmos pheric temperatures which is primarily insoluble in mineral lubricating oil but which contains desired oil-soluble pour-depressant constituents.

9. The method 01' producing a pour point reducing agent for a mineral lubricating oil, which comprises subjecting an oil refinery residue selected from the group consisting of cracked petroleum tar, extraction products separated in the solvent refining of petroleum fractions, and extraction products separated from adsorbent filters in the refining of petroleum fractions, to cracking at temperatures of around 800 to 1000 F. and under superatmospheric pressure to reduce the material to a high melting point pitch representing a residuum in 'excess of by weight on the weight of the original residue, said pitch being primarily insoluble in mineral lubricating oil but containing desired oil-soluble pour-depressant constituents in concentrated form.

10. The method of producing a pour point reducing agent for a mineral lubricating oil, which comprises subjecting an oil refinery residue consisting of the extraction product separated from adsorbent filters in the clay vapor treating of cracked naphtha to substantial cracking at high vtemperature and under superatmospheric pressure to reduce the material to a pitch which is primarily insoluble in mineral lubricating oil but which contains desired oil-soluble pour-depressant' constituents.

11. The method of producing a pour point reducing-agent for a mineral lubricating oil, which comprises subjecting an oil refinery residue consisting of the extraction product separated in the solvent refining of alubricating oil stock, to substantial cracking-athigh temperature and under superatmospheric pressure to reduce the material to a pitch which is primarily insoluble in mineral lubricating oil but which contains desired oil-soluble pour-depressant constituents.

12. The method of producing a pour point reducing agent for a mineral lubricating oil, which.

cracked petroleum tar, extraction products separated in the solvent refining oi! petroleum fractions, and extraction products separated from adsorbent filters in the refining of petroleum fractions.

14. A lubricating oil of relatively low pour point comprising a blend of a mineral lubricating oil of relatively higher pour point with a minor proportion of a highly concentrated pour point depressant obtained by recracking at high temperature and under superatmospheric pressure a pressure tar to a pitchy residue which is primarily insoluble in mineral lubricating oil but in which oil-soluble pour-depressant constituents are highly concentrated.

15. A lubricating oil of relatively low pour point comprising a blend of a mineral lubricating oil oi relatively higher pour point with a minor proportion of oil-soluble constituents extracted from a pitch whlchis primarily insoluble in the lubricating oil and obtained by substantial cracking at high temperature and under superatmospheric pressure of an extraction product separated from adsorbent filters in the clay vapor treating of cracked naphtha.

16. A lubricating oil of relatively low pour point comprising a blend of a mineral lubricating oil of relatively higher pour point with a minor proportion of oil-soluble constituents extracted from a pitch which is primarily insoluble in the lubricating oil and obtained by substantial cracking at high temperature and under superatmospheric pressure of an extraction product separated in the solvent refining of a lubricating oil stock.

ROBERT E. MANLEY. HOWARD H. GROSS.

CERTIFICATE OF CORRECTION.

Patent No. 2,040,057. May 5, 1936.

ROBERT E. MANLEY, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, line 67, and page 3, first column, lines 16 and 42-, claims 1, 2 and 3 respectively, after the word "fractions" insert a. comma; page 3, second column, line 58, claim 7, after "constituents" insert a comma; page 4, second column, line 9, claim 13, after "cracking? insert the words at high tempera.-

Signedangl sealed this 3rd day of November, A. D. 19:56.

Henry Van Arsda-le (Seal) Acting Commissioner of Patents.