US2037886A - Process for breaking petroleum emulsions - Google Patents

Description

Patented Apr. 21, 1936 UNITED STATES PATENT OFFICE PROCESS FOR BREAKING PETROLEUM EMULSIONS No Drawing. Original application December 31,

1934, Serial No. 760,032. Divided and this application December 6, 1935, Serial No. 53,269

'7 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.

6 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.

10 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 settings.

The object of our 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.

Briefly described, our 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 per- 5 mitted to remain in a quiescent state after treatment, or is subjected to other equivalent separatory procedures, the present application being a division of our pending application Serial No. 760,032, filed December 31, 1934.

our Process consists WW of Ebdly ke t g a tty acid body or It is well Tiit'fiht certa'ifi fffiti r fatty bodies can be subjected to treatment so as to yield keto fatty acids, that is, fatty acids in which a ketonic group (a carbonyl group) is present. One example is the conversion of riclnoleic acid into Such ketohydroxyticularly other hydroxy acids, to give polymerized acids, or more correctly, poly keto acids which have the same analogy to keto acids as triricinoleic acid or diricinoleic acid has to ricinoleic acid.

Poly keto fatty acids can be obtained by the 45 cautious oxidation of unsaturated, hydroxylated,

fatty bodies of various kinds. In the co-pending application for patent of De Groote & Keiser,

Serial No. 760,025, filed December 31, 1934, there is described the production of unsaturated, hy-

droxylated, fatty materials obtained by the oxith other acids, par

dation of relatively highly unsaturated, non-hydroxylated material, such as semi-drying oils, drying oils, marine oils, or their fatty acids or mixtures thereof. The raw material, prior to oxidation, is characterized by a relatively high 5 iodine number, such as 120 to 180 or 190.

In the production of poly keto fatty acids or their salts or esters, by pressure oxidation at relatively low temperatures, one may employ any suitable unsaturated, hydroxylated fatty matel0 rial, such as castor oil, riclnoleic acid, diricinoleic acid, material of the kind described in the aforementioned application for patent of De Groote and Keiser, or any other suitable material. In our co-pending application for patent Serial No. 15 760,031, filed December 31, 1934, we have described the poly keto fatty acids and their salts and esters as new compositions of matter, and also a new method for producing the same, i. e., pressure oxidation at relatively low temperatures, 20 such as 135 C. or less.

It is suflicient for the present purpose to state that the process of our said application for patent produces materials high in poly keto fatty acids, which have the same characteristics as poly keto fatty acids derived by esterifying or condensing a keto fatty acid, such as keto-hydroxy fatty acid with ricinoleic acid or diricinoleic acid or oleic acid or triricinolein.

Briefly described, the method of producing such poly keto fatty acids by pressure oxidation, as disclosed in our aforementioned co-pending application for patent 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. pressure by means of ordinary moist air and at a temperature of not over 135 C., and preferably at about 120 C., for approximately 10 to 30 hours. A small amount of a fat splitting sulfonic acid, such as approximately of Petrolf reagent (oil-soluble petroleum sulfonic acids) may be present during oxidation.

It is well known, of course, that castor oil is an alcohol, and in fact, a secondary alcohol. It is furthermore well known that ketonic acids are produced by the cautious oxidation of hydroxy acids containing the secondary alcoholic group,

as, for example, oxidation of lactic acid to pyroracemic acid. In said reaction the CH(OH) group is converted into a CO group. The cautious oxidation of castor oil or ricinoleic acid conducted under the previously specified conditions results in the formation of a ketonic acid, which may be indicated by the following formula:

However, oxidation not only takes place at the hydroxyl 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:

However, it is well known that oxidation reactions tend to polymerize or form ester acids, ethers, etc., and thus: the resultant product represents ketonic acids in the polymerized form, i. e., derived from two or more molecules, at least one of which must contain a ketone group.

The formation of ketohydroxystearic acid in the usual manner (see Lewkowitsch, Chemical Technology of Oils, Fats and Waxes, 6th edition, volume 1, page 240) with subsequent reaction with ricinoleic acid, diricinoleic acid, oleic acid, triricinolein, etc. results in a compound representing substantially nothing other than poly keto acids. On the other hand, we are aware that the products obtained by pressure oxidationin the manner referred to previously, may result in products containing a significant amount or majority of poly keto acids, but may contain certain other non-ketonic material of the kind present in various conventional or special blown oils. Since such non-ketonic materials are also effective quite frequently for the treatment of oil field emulsions, we prefer to use the impure form of poly keto acids or their salts or esters, as obtained by pressure oxidation This is a matter of pure economy. The pure forms, relatively free, from extraneous materials, may be employed.

We are 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. We are also aware that in the case of the common non-fatty ketonic acid aceto-acetic acid, that certain reactions are known to take place which suggest that aceto-acetic acid may, asfar as those reactions are concerned, react more as an aldehyde or as an aldehydic acid than as a ketonic acid. Such wandering of a hydrogen atom and change in position of a double bond is referred to as'keto-enolic tautomerism (Bernthsen, Textbook of Organic Chemistry, 2d edition, 1931, page 231). We believe that this or a comparable change may take place in 7 these poly ketonic acids or bodies previously described andpossibly in regard to some reactions, these poly keto acids or esters thereof act more as if they were aldehydic acids or esters or salts thereof. In other words, if these poly ketonic acid bodies are to be used in a mixture where aldehydic acids would be incompatible, it is also likely that these poly ketonic 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 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, i. e., that both have the carbonyl (CO) radical present, and their ultimate composition in carbon atoms, hydrogen atoms, and. oxygen atoms is identical.

It is understood, of course, that these polymerized ketonic acids or their esters may be converted into salts or esters in the manner generally employed for the manufacture of salts or esters. However, it should be borne in mind that saponification of the kind which would decompose the polymerized material into its simpler form in the same manner that diricinolein could be decomposed into twomolecules of ricinoleic acid, is objectionable and cannot be employed. Due to the low cost of castor oil and the low cost of the hydroxylated unsaturated materials described in the co-pending De Groote and Keiser application for patent previously referred to, it so happens that the products commercially produced will be derived from esters as raw materials and that the amount of free acidic material, after pressure oxidation, is relatively low. In such instances where it is desirable to eliminate this residual acidity, it is best accomplished by means of a relatively weak base, such as triethanolamine, as in the case of the preferred example, which will be described subsequently. In some instances, it might be desirable to mix an alcohol, particularly a polyhydric alcohol, such as glycerine or ethylene glycol with the pressure-oxidized bodies and then heat so as to eliminate the carboxylic hydrogen. In any event, the polymerized ketonic bodies may be converted into any suitable form by means of conventional reactions, provided that the material is not decomposed so as to destroy the carbon--. yl radical or the polymerized state, and thus pro duce simple ketonic fatty acids, as difierentiated from poly ketonic acid in the same manner as ricinoleic acid is differentiated from diricinoleic acid.

The manufacture of the demulsifying agent that we prefer to use in practicing our process, is carried out in the following manner: Approximately 4,000 lbs. of castor oil are placed in a vessel of a convenient kind equipped with a suitable means for heating the same to approximately 135 C. and also for cooling the heated mass, if desired. Similarly, the vessel should be equipped for maintaining pressure during oxidation at any desired point, such as 45 lbs. or as much as 75 lbs. mately 400 lbs. of linseed oil of either the boiled type, with added metallic driers, such as cobalt, linoleate, manganese, resinate etc. or the unboiled type. Approximately 40 lbs. or less of Petroif reagent are added. The mass is then heated up to approximately 125 C. and oxidation, by means of air, is started, and the temperature maintained during oxidation at approximately 120 C. Oxidation is carried on for approximately 20 hours. At the end of the oxidation period the material will show some free carbo-xylic acidity, which may be removed by esterificatio-n with an alcohol, particularly a polyhydric alcohol,

p at To this castor oil there is added approxi LULI UUIVII UUI l lUlU such as glycerine or ethylene glycol. The product so obtained is ready for use in breaking oil field emulsions, either alone or in suitable admixture with other reagents or demulsifying agents. In many instances the most effective treatment is obtained without the final neutralization with triethanolamine. As a matter of practical convenience, we prefer to dilute the reagent with 50%, by weight, of a solvent composed of equal volumes of solvent naphtha and methyl alcohol. The use of demulslfying agents consisting of various sulfo acids, or carboxy acids, or compounds having both a sulfo group and a carboxyl group, is well known in the treatment of waterin-oil emulsions. In the use of conventional demulsifying agents it is the common practice to use them not only in the form of acids, but also in the form of salts or esters, or half salts, or half esters, or ester salts, in case of dibasic acids. The salts generally employed are the sodium salt, potassium salt, ammonium salt, calcium, magnesium, the triethanolamine salt, etc. The esters may be employed such as the methyl ester, ethyl ester, propyl ester, butyl ester, amyl ester, hexyl ester, cetyl ester, etc. Aromatic or cyclic ester may be employed. What has been said in regard to the use of conventional demulsifying agents applies also to the materials employed as the demulsifying agent of our process.

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 our 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 demulsifying of the modiiaaa atrra...

It is well known that conventional demulsifying agents may be used in a water-soluble form, or

' concentration employed. This same fact is true in regard to the material or materials employed as the demulsifying agent of our process.

As stated previously, it has been so common to use a conventional demulsifying agent derived from an acid in the form of the acid itself, or in the form of a salt, or in the form of an ester, that the expression acid body is frequently employed to mean the acid itself, or an ester thereof, or salt thereof. The word body is herein employed in this same sense in conformity with its prior usage in the trade, and particularly in various patents of the prior art. Half salts and half esters are considered as salts, and esters, respectively.

In practicing our process a treating agent or demulsifying agent of the kind above described is brought into contact with or caused to act upon the emulsion to be treated, in any of the 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 our invention, what we claim as new and desire to secure by Letters Patent is:

1. A process for breaking a petroleum emulsion of the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsifying agent comprising a salt-freepoy keto fatty 2. A process for breaking a petroleum emulsion of the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsify- L ing agent comprising a poly keto fat in the form of an ester 3. A process for breaking a petroleum emulsion of the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsifying agent comprising a poly keto fatty acid body in the form of an acid.

4. A process for breaking a petroleum emulsion of the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsify- 40 ing agent comprising a poly keto fatty acid body in the form of an ester, derived at least in part from castor oil.

5. A process for breaking a petroleum emulsion of the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsifying agent comprising a poly keto fatty acid body in the form of an acid, derived at least in part from castor oil.

6. A process for breaking a petroleum emulsion of the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsifying agent comprising a poly keto fatty acid body in the form of an ester, derived by pressu re px i d a tion of castgnfloil at a relatively low tempe ur 7. A process for breaking a petroleum emuls on of the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsifying agent comprising aflpply ggi o fat; ag i d lgpdy fio in the form of an acid, 3 enved tt fifesiure unfit tion of castor oil at a relatively low temperature.