US1562156A - Process for purifying mineral oils - Google Patents

Description

Patented Nov. 17, 1925 UNITED STATES PATENT OFFICE.

JACOB F. FABER, OF LOS ANGELES, AND HENRY C. HANNA AND MARVIN L. CHAP- IPELL, OF EL SEGUNDO, CALIFORNIA, ASSIGNORS T STANDARD OIL COMPANY, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA.

PROCESS FOR PURIFYING MINERAL OILS.

1T0 Drawing.

To aZL'whom it may concern:

Be it known that we, JACOB F. FABER, a

citizen of the United States, residing at I Process for Purifying Mineral Oils, of

which the following is a specification.

Our invention relates to a process for ing mineral oils.

An object of the invention is to purify a petroleum oil so as to produce a treated oil which will not emulsify when commingled with water or a caustic soda solution.

Another object of the invention is to provide a process or method of so treating petroleuin oils that an emulsion will not be formed during treatment thereof.

Another object ofthe invention is to produce a lubricating oil suitable for lubricating steam turbines or other machinery in which the lubricating oil may come into contact or become commingled with water or steam.

Another object of the invention is to produce a lubricating oil substantially free from einulsifying constituents.

Another object of the invention is to eliminate from a lubricating oil during treatment thereof substantially all its emulsifying constituents and thereby prevent a partial or complete emulsification of the lubricating oil during treatment.

Another object of the invention is to produce a lubricating oil substantially, free from resins, gums, organic surfo-acids.

Another object of the invention is to ac complish the above with a minimum, loss in the final yield of treated oil.

Other advantages of the invention will appear in -thepractical useof the same and from the following description.

During the acid treatment of petroleum oil by means of sulphuric acid certain polymerized, ox and oxy-sulfo compounds are formed w ich have a preferential oil solubility and remain in solution in the oil after the acid sludge has been separated from the oil. These compounds cannot be completely removed from the oil by means organic acids, phenols or Application filed 'Ianuary26, 1922. Serial No. 531,991.

of any of the well known methods of wash mg with water or neutralizing with caustic soda. Upon any such attempt to wash the treated oil with Water or neutralize the same with caustic soda the said compounds will cause the formation of emulsions of oil and water. That portion of said emulsifying constituents, which is removed by" neutralizing' with caustic soda or washing with water, is emulsified with a certain percentage ofthe treated oil and the removal thereof dimlnlshes the yield of said treated 'oil. The portion of said emulsifying constituents remaining in the treated oil will cause the same to form emulsions when in use, slnce the oil may come into contact; with water, or sea water which is usedin the coolmg system of steam turbines. In' particular, in the manufacture of lubricating 011s from an asphalt or mixed base crude oil by well known methods, there is lost during the neutralizing and washing operations from 3 to 15% by volume of the treated oil, and at best only an imperfect separation of the emulsifying constltuents can be had.

Certain methods have been heretobefore developed with some success to employ acid sludge or derivatives thereof as an agent to remove the above described emulsifying constituents. perior results can be obtained by employing a properly concentrated water solution of salt of a petroleum car'boxylic acid as an agent or solvent for extracting theremulsifying constituents. We have also established an apparent paradox, because in We have discovered that susmall proportions or dilute solutions petroleum carboxylic compounds in fact constithe acid by means of a water solution of a metallic base from. an asphalt or mixed base crude petroleum oil, or a derivative therefrom, which has been treated with'sulphuric acid or other oxidizing agent. Ihe

metallic base neutralizes the carboxylic acid to form a water soluble carboxylic salt. Also water soluble carboxylic salts may be obtained by extracting the acid from any asphalt or mixed base crude petroleum oil or derivative thereof, by treating the same with a water solution of a metallic base to neutralize the natural carboxylic acids contained therein.

In the manufacture of lamp oils from. an asphalt or mixed base crude petroleum oil, it is customary to treat what is known as a lamp oil distillate with relatively large amounts of fuming sulphuric acid, which treatment produces small amounts of a pctroleum carboxylic acid in addition to the natural petroleum carboxylic acid contained therein. This carboxylic acid may be neutralized with a water solution of caustic soda or other metallic base. This extract is commonly known as spent caustic solution and contains in addition to the soluble petroleum carboxylic acid salts, certain percentages of sodium sulphite and sodium sulphate. This sodium sulphiteand sodium sulphate does not interfere in our process and need not be removed. This said spent caustic solution obtained in the manufacture of lamp oils, or any other spent caustic solution obtained in refining petroleum oils and containing soluble petroleum carboxylic salt, may serve as our demulsifying agent after being concentrated to the required degree. The solution embodying our demulsifying agent should be concentrated by any well known method until'it contains preferably from 5% to 25% by weight petroleum carboxylic salts.

In practice we prefer to apply our invention by combining our demulsifying solution with the alkali necessary for the neutralization of the acids remaining in an acid treated oil after separation of the acid sludge. The combined demulsifying solution and alkali may be added to the acid treated oil and the removal of the above described emulsifying constituents will take place simultaneously with the neutralization of the acids present in the oil. This procedure will eliminate the formation of any stable emulsion during the refining operation. In the refining of lubricating oils by using a quantity of the mixed concentrated spent caustic-soda solution and alkali equal to from 10 to 30% of the volume of lubricating oil to be treated the resulting mixture as previously stated preferably contains between 5% to 25% petroleum carboxylic salt. The quantity of alkali present is not critical and will depend upon the acidity of the oil to be treated. The

combined solution is added to the oil and.

agitated until commingled and is then allowed to stand at rest from 2 to 16 hours at a temperature ranging preferably from that specific application.

approximately 130, to 180 F., or until stratification takes place; The water solution containing the impurities should then be drawn off and the oil tested for emulsi fying constituents. If any of'the latter re,- main the oil should be further treated with an alkaline solution of our demulsifying agent. After the treated oil is found to contain no further emulsifying constituents, I it may be given a water or alkaline wash, if necessary, to remove all traces of our demulsifying solution and may then be finished by well known methods.

In lieu of our preferred application of our invention the acid treated oil may be first independently neutralized by an alkaline solution and the oil thereafter treated with our demulsifying agent. Likewise the oil may be treated by our demulsifying agentdirectly after separation of the acid sludge and prior to neutralization, so that neutralization follows rather than proceeds or occurs simultaneous to our demulsifying treatment.

Our demulsifying agent may be employed to remove the emulsifying constituents contained in finished lubricating oils which were not extracted during the refining thereof. This may be readily accomplished by combining the finished oil and our demulsifying solution and maintaining the mixture at proper temperature until stratification takes place.

The petroleum carboxylic salt for the best results should be as free as possible from neutralized sulpho acids. By obtaining these petroleum carboxylic salts through extracting petroleum carboxylic acids by means of a water solution of a metallic base from an asphalt or mixed base crude petroleum oil, the resultant petroleum carboxylic salt will be free from sulpho nated salts or soaps and will be superior for this reason for some purposes than those obtained from an oil treated with sulphuric acid.

It will be understood that with different oils different proportions, temperatures and times will give best results. The proper proportions, temperature and times may be determined for any oil by preliminary tests. Ive have endeavored to describe a specific application of our invention but we do not intend to limit ourselves to the details of We claim: 1. A process of refinmgpetroleum oils which consists in treating an oil with sulphuric acid, separating the treated oil from the acid sludge and neutralizing the treated 11% I oil in the presence of a petroleum carboxylic salt to prevent the formation of a persistent emulsion, said petroleum carboxylic salt being obtained by extracting petroleum carboxylic acids from crude petroleum oil by 1% means of water solution of a metallic 'base,

oil .fromwhich the sludge has been removed.

3., A process of treating petroleum oils to prevent the formation of a persistent emulsion which consists in adding an aqueous solution containing approximately 5 to of a carboxylic salt derived by extractingpetroleum carboxylic acid from crude petroleum oil by means of a water solution of a metallic base to an acid treated oil from ,which the sludge has been removed and ,the treated oil neutralized.

4. A process of refining petroleum oil which consists in treating the oil with sulphuric acid, separating theacid sludge from the oil, and neutralizing the treated oil with a solution'of caustic soda'and carboxylic salt said'carboxylic salt being derived-by extracting petroleum carboxylic acids from crude petroleum oil by means of a metallic base, whereby a petroleum carboxylic salt is obtained .free of sul honated soap's.

5. A process of treating petroleum oils to prevent the formation of a persistent emulsion, which consists in addinga water sol.- uble carboxylic salt, derived by extracting petroleum carboxylic acid from petroleum oil by means of a water solution of a metallic base, to an acid treated oil from which the sludge has been removed, the said pe'- troleum oil being free of sulfonic acids.

6. A process of refiningpetroleum oils, which consists in treating the oil with sulfuric acid, separating the acid sludge from the oil and neutralizing the treated oil with .a solution of caustic soda and carboxylic salt, said carboxylic salt being derived by extracting carboxylic acid from petroleum oil free of sulfonic acids by means of a metallic base, whereby a petroleum carboxylic salt is obtained free from sulfonated soaps.

Signed at Los Angeles, California, this 20th day of January, 1922.

JAooB F. FABER.

HENRY o. HANNA. MARVIN I2. CHAPPELL