US2052282A - Processes for breaking petroleum emulsions - Google Patents

Description

Patented Aug. 25, 19 36 Es PATENT OFFICE' PROCESSES FOR BREAKING PETROLEUM EMULSIONS Melvin De Groote, St. Louis, Mo., assignor to Tretolite .Company, Webster Groves, Mo., a corporation of Missouri I No Drawing.

4 Claims.

This invention relates to the treatment of emulsions of mineral oil and water, such as petroleum emulsions, for the purpose of separating the oil from the water.

Petroleum emulsions are .of the water-in-oil type, and comprise fine droplets of naturallyoccurring waters or brines, dispersed in a more or less permanent state throughout the oil which constitutes the continuous phase of the emulsion.

They are obtained from producing wells and from the bottom of oil storage tanks, and are commonly referred to as cut oil, "roily oil," emulsified oil and bottom settlings.

The object of my invention is to provide a novel and inexpensive process for separating emulsions of the character referred to into their component parts of oil and water or brine. V

Briefly described, my process consists in subjecting a petroleum emulsion of the water-in-oil type to the action of a treating agent or demulsifying agent of the kind hereinafter described, thereby causing the emulsion to break down and separate into its component parts of oil and water or brine, when the emulsion is permitted to remain in a quiescent state after treatment, or is subjected to other equivalent separatory procedures.

The treating agent or demulsifying agentused in my present process consists of a chemical compound characterized by the presence of both a keto fatty acid residue derived from castor oil and a dicarboxy acid residuein the same molecule; said dicarboxy acid residue being obtained from an acid of the formula type (CHa)c(COOI-I)z, in which n has a value of at least 5 and not more than 8. y

In a co-pending application for patent of Melvin De Groote, Bernhard Keiser and Arthur F. Wirtel, Serial No. 760,033,1lled December 31, 1934,

40 there is described a process for breaking petroleum emulsions by means of unpolymerized keto fatty acid bodies or materials. It is well known that fatty acids or fatty bodies can be subjected to chemical treatment so as to yield keto fatty acids, that is, fatty acids ln which a ketonic group (a carbonyl group) is present. One example is the conversion of ricinoleic acid into ketohydroxystearic acid. (See Lewkowitsch "Chemical Technology of Oils, Fats and Waxes, 6th edition, volume 1, page 242) In jfai general 'way, the manufacture of such ket'onic acids is dependent upon the'treatment of an un- Qsaturated fatty body or fatty acid, such as fricinoleic acid, oleic acid, or the like, with a "55 halogen, such as bromine, so as to form a halogen Application December 21, 1935, Serial No. 55,619

addition product, for'example, ricinoleic acid dibromide, which is then converted into ricinstearolic acid. Ricinstearolic acid, on treatment with sulfuric acid, yields ketohydroxystearic acid.

In a second co-pending application for patent of Melvin De Groote, Bernhard Keiser and Arthur F. Wirtel, Serial No. 760,032, filed December 31, 1934, there is disclosed the use of polyketo fatty acid bodies for the purpose of breaking petroleum emulsions. Polyketo fatty acids may be derived 10 by polymerization of keto fatty acids which have been previously derived in the manner described by Lewkowitsch, mentioned above.

In the present application, the expression keto fatty acids" or keto fatty acid bodies" is intended to include .both unpolymerized keto fatty acid bodies and polymerized (polyketo) fatty acid bodies. It is more economical in many instances, to prepare the reagent employed in the present process from a polyketo fatty acid body than from an unpolymerized one, the reason being that 7 it is more economical to produce polyketo fatty acid bodies than unpolymerized keto fatty acid bodies.

In the production of polyketo fatty acids or their salts or esters, by pressure oxidation at relatively low temperatures, one may employ any suitable unsaturated, hydroxylated fatty material, such as castor oil, ricinoleic acid, diricinoleic acid, and other materials of the kind described in the aforementioned applications for patent of De Groote, Keiser and Wirtel, or any other suitable material. A third co-pending application of Melvin De Groote, Bernhard Keiser and Arthur F. Wirtel, Serial No. 760,031, filed December 31, 1934, discloses a novel method for producing polyketo fatty acids and their salts and esters, said method contemplating pressure oxidation at relatively low temperatures, such as 135 C. or less, and

the product of said method consisting of materials 40 high in polyketo fatty acids, which have the same characteristics as polyketo fatty acids 'derived by esterifying or condensing a keto fatty acid, such as ketohydroxystearic fatty acid with ricinoleic acid, or diricinoleic acid, or oleic acid, or triricinclein.

Briefly described, the method just referred to for producing such polyketo fatty acids by pressure oxidation, consists in mixing an unsaturated, hydroxylated, fatty body of the kind previously described, such as castor oil, with not over 10% of a true drying oil, such as linseed oil, or perilla oil, or the acids thereof, and subjecting the same to pressure oxidation at approximately 15 to '75 lbs. gauge pressure by means of ordinary moist air and at a temperature of not over 135 C., and preferably at about 120 0., for approximately -10 to 30 hours. A small amount of a fat splitting sulfonic acid, such as approximately 5 of Petrofi. reagent (oil-soluble petroleum sulfonic acids) may be present during acid," which may be indicated by the following formula However, oxidation not only takes place at the lhydroxyl position, but also at the ethylene linkage, with probably the absorption of oxygen and then conversion into hydroxyl groups, and thus the ketonic acid produced may represent a saturated, dihydroxy. acid which may be indicated by the following formula:

on on OHs-(CHflr-CCF-CHa-AH-H--(CH:)7COOH However, it is well known that oxidation reactions tend to polymerize or form ester acids,

7. others, etc., and thus the resultant product represents ketonic acids in the polymerized form, f. e., derived from two or more molecules, at least one (u of which must contain a ketonic group. Obviously, such ketonic fatty acids may be of theoxy or hydroxy type as well.

The formation of ketohydroxystearic acid in the-usual manner (see Lewkowitsch Chemical Technology of Oils, Fats and Waxes, 6th edition, volume 1, page 242) with subsequent reaction with ricinoleic acid, diricinoleic acid, oleic acid,

triricinolein, etc. results in a compound representing substantially nothing other than polyketo acids. On the other hand, I am aware that the products obtained by pressure oxidation in the manner referred to previously,- may result in products containing asigniflcant amount or majority of polyketo acids, but may contain certain other-non-ketohic material of the kind presentin various conventional .or special blown oils. Since such non ketonic materials are also effecti've quite frequently for the treatment of oil held emulsions, and therefore, inproducing the demulsifying agent employed in. my present process, I prefer to use the. impure form of polyketo acids or their salts'orr esters, as obtained by pressure oxidation. This ispurely a matter' of" economy. The pure forms, relatively free from extraneous materials, may be employed. V

I am fully aware that migration may take place in a fatty molecule. For instance,'that the formation' of stearolactone from hydroxystearic acid appears to depend on the migration of the alcoholiform hydroxyL. I am also aware that inthe case of the common non-fatty ketonic acid, aceto-acetic acid, that certain reactions are how to .take place which suggest that acetoacetic acid may, as far as those reactions are concerned, react more as an aldehyde or as an aldehydic' acid thanas a ketonic acid. Such wandering of a hydrogen atom and change in position of a double bond is referred to as ketoerlolic tautomerism (Bernthsen, "Textbook of Organic Chemistry, 2nd edition, 1931, page 231). I believe that this or a comparable change may 5 take place in these polyketonic acids or bodies previously described, and possibly, in regard to some reactions, these polyketo acids or esters thereof act more as if they were aldehydic acids, or esters, or salts thereof. In other words, if these polyketonic acid bodies are to be used in a mixture where aldehydic acids would be incompatible, it is also likely that these polyketonic acids or their esters may be incompatible, for the reason that they really may be aldehydic acid bodies. It is to be noted that the reagents of the kind employed for determining the presence of the carbonyl group in ketones also usually detect the presence of the carbonyl group in aldehydes. It is to be understood that in the appended claims where the products are characterized by the presence of ketonic radicals, that such acids might ultimately prove to be aldehydic acids, or at least, convertible under certain conditions of use, or else under certain conditions of identification, possibly they become converted into aldehydic acids, and it is not intended that the word ketonic" or keto" be interpreted as excluding the meaning of aldehydic" in the sense previously described or discussed, 1. e., that both have the carbonyl (CO) radical present, and their ultimate composition in carbon atoms, hydrogen atoms, and oxygen atoms, is identical.

In United States Letters Patent No. 2,023,995, to Melvin De Groote and Bernhard Keiser, dated December 10, 1935, there is disclosed a process for breaking emulsions by means of esters derived by reaction between a dibasic acid of the type (CH2)n(COOH)2, in which n has a value of at least 5 and not more than '8, and a hydroxylated fatty body, such as ricinoleic acid, triricinolein, etc. More specifically, the dibasic carboxy acids employed to produce the demulsifying agent used in the process of said De Groote and Keiser patent includes the following;

Pimelic acid (HOOC(CH2)5COOH) Suberic acid (Hoocwrnncoom Azelaic acid (HOOC(CH2)1CO0H) Sebacic acid (noomcnmcoom due in the same molecule, the dicarboxy acid residue being derived from an acid of the; type (CH2)n(COOH)2, in which n has a value of at 0 least 5 and-not more than 8. The formation of such materials is relatively simple, since .the keto fatty acid may represent the acid alcohol type of reagent. In the same sense that ricin'oleic acid is an acid alcohol, one may obtain the same reaction from one molecule of keto fatty acid and one molecule of the dibasic carboxy acid as one would obtain from a molecule of ricinoleic acid and a molecule of oxalic acid. Thus, one may form a new acid having two carboxyl radicals by 70 esterification between one of the carboxylic hydrogens of the dibasic carboxy acid and the 'hydroxyl of the acid. Needless to say; just as one can form a trimolecular acid, such as triricinoleic acid, likewise, one can combine two molecules of 76 keto fatty acid with one molecule of a dibaslc carboxy acid by reaction involving the two carboxyl radicals of the dibasic acid. Likewise, any other alcohol acid type of material such as ricinoleii: acid, hydroxystearic acid, or the condensation product of ethylene glycol with oxalic acid or 'phthalic acid or maleic acid, may serve as a which there is no free carboxyl, such as a salt.

bridge or a connecting link by combination with a molecule of keto fatty acid and a molecule of 'a dibasic carboxy acid. Such material used as a connecting link or bridge, of course, must be amphoteric, if it can be employed to combine with a hydroxyl radical of an oxy acid and the carboxyl' radical of a dibasic carboxy acid. Obviously, where it combines with the carboxyl of an acid, one may use an oxy acid material in or ester. v

Likewise, in any case where a carboxylic .hydrogen remains, such carboxylic hydrogen may be converted into salt by neutralization with a suitable base, such as sodium hydroxide, potassium hydroxide, calcium hydroxide, triethanolamine,

etc. Such free carboxylic hydrogen may be converted into an ester, such as methyl ester, ethyl ester, propyl ester, or into an aromatic, cyclic, or aralkyl ester.

The keto fatty acid may be of the hydroxy type. Such keto acids may, of course, act as an alcohol, and thus combine directly with the carboxyl of a dibasic carboxy acid.

Other means of combination are readily available, such'as the formation of a diglyceride in which a molecule of keto fatty acid and a molecule of a dibasic carboxy acid is united with a molecule of glycerol, so as to leave one hydroxyl group and one carboxyl group uncombined.

Likewise, such reaction could be continued seas to yield a triglyceride free from any uncombined hydroxyl or carboxyl groups. Likewise, two molecules of a keto fatty acid could be reacted with one molecule of glycerol, and subsequently further reacted with one molecule of a dibasic carboxy acid, so as to yield a product in which there is aresidual carboxyl group. One molecule of a keto fatty acid and one molecule of adibasic' carboxy acid'can be united by means of ethylene glycol or some similar glycol.

As previously remarked. where a keto fatty acid is acting by virtue of its alcoholic hydroxyl, i. e., acting as an alcohol, one need not employ the acid itself, but one may employ any suitable salt, such as a sodium salt, ammonium salt, potassium salt or an amine salt, such as a triethanolamine salt, etc. Where the oxy acid is acting .by virtue of its carboxylic hydrogen, one need not employ the acid itself, but one might employ a-combination wherein the alcoholic hydroxyl has already combined with some other acid, such as ricinoleic acid. All these reactions are essentially'esteriflcation reactions. Esteriflcation reactions are best promoted at a fairly high temperature, and preferably slightly above the boiling point of water. The passing of dry hydrochlric;;acid gas hastens the reaction. Any conventional means may be employed to hasten these reactions, such as the passing of dry carbonic added thereto 314 lbs. of glycerol. The mixture is heated to approximately 110 C. and dry carbon dioxide gas is passed through the mixture with constant stirring, until the acid value remains constant, based on tests of samples taken at hourly intervals. If the reaction does not proceed rapidly enough, a higher temperature, say, 125 to 135 0., may be employed. If desired, dry hydrochloric gas, or even dried air, may be substituted for the dry carbonic acid gas. The product thus obtained is a very efficient demulsifying agent, especially after dilution with some suitable solvent, so as to reduce its viscosity. One or more of the following will serve as a suitable solvent: benzol, solvent naphtha, kerosene, or propyl alcohol.

If desired, any free acidity which is present in .7

the preferred reagent may be neutralized by triethanolamine or by any other suitable amine, such as monoamylamine, benzylamine, etc. The free acidic carboxyl may be converted into a salt, such as sodium, potassium, or ammonium salt. The free acidic carboxyl, of course, may be combined with an alcohol, such as ethyl, methyl, or propyl alcohol, or with glycerol.

Conventional demulsifying agents employed in the treatment of oil field emulsions are used as such, or after dilution with any suitable solvent,

such as water; petroleum hydrocarbons, such as gasoline, kerosene, stove oil; a coal tar product, such as benzene, toluene, xylene, tar acid oil, cresol, anthracene oil, etc. Alcohols, particularly aliphatic alcohols, such as methyl alcohol, ethyl alcohol, denatured alcohol, propyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, etc., may be employed as diluents. Miscellaneous solvents, such as pine oil, carbon tetrachloride, sulfur dioxide extract obtained in the refining of petroleum, etc., may be employed as diluents. Similarly, the material or materials employed as the demulsifying agent of my process may be admixed with one or more of the solvents customarily used in connection with conventional demulsifying agents. Moreover, said material or materials may be used alone or in admixture with other suitable well known classes of demulsiiying agents, such as demulsifying agents of the modified fatty acid type, the petroleum sulfonate type, thealhlated sulfa-aromatic type, etc.

It is well known that conventional demulsifying agents may be used in a water-soluble form, or in an oil-soluble form, or in a form exhibiting both oil and water solubility. Sometimes they may be used in a form which exhibits relatively limited water solubility and relatively limited oil solubility. However, since such reagents are sometimes used in a ratio of 1 to 10,000, or 1 to 20, 000, or 1 to 30,000, such an apparent insolubility in oil and water is not significant, because said reagents undoubtedly have solubility within the concentration employed. This'same fact is true in regard to the material or materials employed as the demulsifying agent of my process.

In practising my process a treating agent or de- 'various ways or by any of the various apparatus now generally used to resolve or break petroleum emulsions with a chemical reagent.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A process for breaking petroleum emulsions of the water-in-oil type, which consists in sub- :Iecting the emulsion to the action of a demulsifying agent comprising a, chemical compound, characterized by the presence of both a keto fatty acid residue derived from castor oil and a dicarboxy acid residue in the same molecule; said dicarboxy acid residue being obtained from an acid of the formula type (CH2)n(COOH) z, in which n has a value of at least 5 and not more than 84 I 2. A process for breaking petroleum emulsions of the water-in-oii type, which consists in subjecting the emulsion to the action of a demulsitying agent comprising a chemical compound in the form of a salt, characterized by the presence of both a keto fatty acid residue derived from castor oil and a dicarboxy acid residue in the same molecule; said dicarboxy acid residue being obtained from an acid of the formula type (CH2)n(COOH)2, in which n has a value of at least 5 and not more than 8.

3. A process for breaking petroleum emulsions of the water-in-oil type, whichconsists in subjecting the emulsion to the action of a demulsifying agent comprising a chemical compound in the form of an acid, characterized by the presence of both a kcto fatty acid residue in .r

the same molecule; said dicarboxy acid residue being obtained from an acid of the formula type (CH2)n(COOH)2, in which n has a value of at least 5 and not more than 8; 4. A process for breaking petroleum emulsio of the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsii'ying agent comprising a chemical compound in the form of an ester, characterized by the presence of both a keto fatty acid residue derived from castor oil, and a ,dicarboxy acid residue in the same molecule; said dicarboxy acid residue'being obtained from an acid of the formula type (CH2)n(COOH)2, in which n has a value of at least 5 and not more than 8. MELVIN DE GROOTE.