US2231753A - Process for resolving petroleum emulsions - Google Patents

Description

atented Feb. 11, 1941 PATENT ornca PROCESS FOR RESOLVING PETROLEUM EMULSION S Melvin De Groote, University City, Mo., assignor, by mesne assignments, to Petrolite Corporation, Ltd., a corporation of Delaware No Drawing. Application February 20, 1939,

Serial No. 257,333

l Claims.

ment of emulsions of mineral oil and water, such as petroleum emulsions, for the purpose of separating the oil from the water, and has for its main object to provide a novel process for resolving or breaking petroleum emulsions of the water-in-oil type.

Petroleum sulfonic acids are produced from a wide variety of petroleum distillates or petroleum fractions, and in some instances, they are produced'from the crude petroleum itself. When produced from crude petroleum itself, it is customary to ise crude oil of the naphthene type, crude oil of the paraflin type, crude oil of the asphaltic type, and mixtures of said three different types of crude oil.

The art of refining petroleum crude or various fractions, using sulfuric acid of various strengths, as well as monohydrate and fuming acid, is a well known procedure. In such conventional refining procedure, petroleum sulfonic acids have been produced as by-products. For instance, in removing the olefinic components, it has been common practice to use sulfuric acid, so as to polymerize the olefines, or convert them into sulfonic acids which are subsequently removed. Likewise, in the production of white oil, or highly refined lubricating oils, it has been customary to treat with fuming sulfuric acid, so as to eliminate certain undesirable components.

In recent years, certain mineral oil fractions have been treated with sulfuric acid, with the primary object of producing petroleum sulfonic acids, and in such procedure, the petroleum sulfonic acids represented the primary objects of reaction, rather than concomitant by-products.

Petroleum sulfonic acid, regardless of whether derived as the principal product of reaction, or as a by-product, canbedivided into the general products, to wit, green acid or acids, and mahogany acid or acids. The green acids are characterized by being water-soluble 0r dispersible. In other words, they form either true solutions or sols. For purpose of convenience, they will be herein referred to as water-soluble, without any effort to indicate whether the solution is molecular or colloidal in nature. The greenacids, as indicated by their name, frequently give an aqueous solution having a dark green or greygreen appearance. They generally appear as a component of the acid draw-ofi, and do not remain behind dissolved in the oil fraction, which has been subjected to sulfuric acid treatment.

The green acids are not soluble in oil, even when,

substantially anhydrous, and certainly are not This invention relates primarily to the treatsoluble in oil when they contain as much as 15% of water. Similarly, their salts obtained by neutralizing the green acids with a strong solution of caustic soda, caustic potash, or ammonia, are not oil-soluble. For convenience of classifl- 5 cation, the ammonium salt will be considered as an alkali salt.

In contradistinction to the hydrophile green acids, there occurs, as in the manufacture of medicinal white oil, the oil soluble type, or the 10 mahogany acids. These mahogany acids are characterized by being soluble in oil, especially when anhydrous, and being soluble in oil, even if they contain some dissolved water. Some of the mahogany acids also show limited hydro- 18 philic properties, to the extent that either some water can be dissolved in the acids, or they, in turn, may dissolve to some extent in water. In some instances their salts, such as the sodium, ammonium, or potassium salt, will dissolve in 20 water to give a colloidal sol. However, regardless of the presence of any hydrophilic properties whatsoever, they always have a characteristic hydrophobe property, as indicated by the 'fact that the substantially anhydrous form, for in- 25 stance, their alkali salts containing 5-12% water, will dissolve in oil. This clearly disti u shes them from the green acids previously referred to, because the green acids in similar form containing the same amount of water, for example, will not dissolve in oil. The green acids as such are essentially hydrophilic and non-hydrophobic in character.

The utility of the mahogany acids in various arts has been enhanced by increasing their water 35 solubility; for instance, converting the mahogany acids into hydroxy alkylamine salts. On the other hand, as far as I am aware, no valuable product of commerce has resulted from decreasing the water solubility of themahogany acids 40 by the addition of some oil soluble basic amine, such as, for example, trlamylamine. The triamylamine salts of mahogany acids, for example, are completely devoid of any solubility in water, which the alkali salts may have exhibited, and show, as would be expected, an increased solubility in hydrophobe solvents.

Green acids are hydrophile in character, as previously stated. Their hydrophile character has been increased by neutralization with mate- 5 rials such as triethanolamine and the like. Such green acid salts having enhanced water solubility, as compared with the ordinary alkali salts, have found application in certain arts.

I have found that if green acids, that is, the s oil-insoluble type, are neutralized with an alkylamine of the kind hereinafter described, so as to produce a water-insoluble product, the resulting material, even though it does not exhibit any marked oil solubility, especially when it contains 5-10% of water, still has pronounced value as a demulsifier for oil field emulsions, either when used alone, or when used in conjunction with other known demulsifying agents. I employ alkylamines of the kind which contain at least one propyl radical and contain no other radical in which there are more than three carbon atoms present. Attention is directed to my co-pending application for patent, Serial No. 193,063, filed February 28, 1938, now Patent 2,153,745. I have also found that sometimes such an amine salt of green acids will mix in with a hydrophobe material and a hydrophile material, so as to produce a homogeneous mixture. The effectiveness of the above described material or composition of matter as a demulsifying agent for oil field emulsions appears to be related to some factor other than its solubility characteristics.

The new composition of matter then which I use as the demulsifier in my improved process for resolving petroleum emulsions, is represented by the described alkylamine salts of hydrophilic nonhydrophobic green petroleum acids, as exemplified by the dipropylamine salt. The! manufacture of said new composition of matter involves nothing more or less than neutralizing the selected petroleum sulfonic acid with a suitable amine until neutral to methyl orange indicator, or other suitable indicator. For purpose of convenience, I prefer that the selected petroleum sulfonic acid contains not over 15% of water. It is understood, of course, that the conventional procedure employing double decomposition, instead of direct neutralization, can be employed in the manufacture of my new material or composition of matter. For instance, the sodium salt of the selected petroleum sulfonic acid can be dissolved in alcohol and the amine hydrochloride added, so that sodium chloride will precipitate. After filtering oif the precipitated sodium chloride, the alcohol can be evaporated and the amine salt recovered. If desired, a mixture of amines, instead of a single amine, may be employed.

There are a large number of alkylamines available which are characterized by having present at least one propyl radical and no other radical having more than three carbon atoms. Suitable examples include monopropylamine, dipropylamine,-tripropylamine, ethyldipropylamine, methyldipropylamine, dimethylpropylamine, diethylpropylamine, dipropylethanolamine, etc.

There is no objection to using an alkylamine of the kind described, even though a hydroxy alkyl radical is present, provided that neutralization of the green acids yields a water-insoluble salt. For instance, as has been pointed out, one might employ dipropylethanolamine or dipropylpropanolamine. Similarly, one might employ dipropylpropanolamine, or an amine containing a glyceryl radical, such as dipropylglycerylamine, provided that the salt derived from the green acids was water-insoluble.

It may be well to point out that hydrophile nonhydrophobe petroleum sulfonlc acid or acids of the green acid type vary somewhat; for instance, the molecular weight may vary within the range of 350-500, or thereabouts. Naturally, these petroleum sulfonic acids may carry some polymerized olefines, free hydrocarbons, or the like, or may even carry a bit of naphthenic acids which represent carboxylated non-sulfonated petroleum acids. As previously stated, these materials are well known commercial products and are available in the open market, either in the form of the acid itself, or in the form of a salt.

In the claims the amine is referred to as basic to indicate that the basicity is in the neighborhood of that of ammonia or triethanolamine. In some instances, the basicity may be somewhat greater, or perhaps slightly less. Basicity is insured in amines of the kind described, because they do not have present an aryl radical attached to the amino nitrogen atom. The limitation which prohibits the use of an amine having more than three carbon atoms excludes the use of amines having a phenyl, naphthyl, or similar aryl radical, which would decrease or destroy the basicity of the amine. The term sulfonic acid used in the claims is intended to refer to a substance that consists either of a single acid or mixture of acids.

The new process that I have devised for resolving or breaking petroleum emulsions of the waterin-oil type involves subjecting the emulsion to the action of a demulsifier consisting of the above described new material or composition of matter. Said material is used either alone, or in admixture with another, or with other conventional demulsifying agents, and its method of use is the same as that generally employed in resolving or breaking petroleum emulsions of the water-in-oil type with a chemical demulsifier. Briefly stated, the conventional method of using a chemical demulsifier to break a petroleum emulsion consists in introducing the demulsifier into the well in which the emulsion is produced; introducing the demulsifier into a conduit through which the emulsion is flowing; or introducing the demulsifier into a tank in which the emulsion is stored. After treatment the emulsion is allowed to stand in a quiescent state, usually in a settling tank and usually at a temperature varying from atmospheric temperature to about 200 F., so as to permit the water or brine to separate from the oil, it being preferable to keep the temperature low enough to prevent the volatilization of valuable constituents of the oil. The amount of demulsifier that may be required to break the emulsion. may vary from 1 part of demulsifier to 500 parts of emulsion, up to 1 part of demulsifier to 20,000 or even 30,000 parts of emulsion.

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

1. A process for resolving petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier comprising a. water-insoluble salt of a basic alkylamine; said amine being characterized by the fact that at least one amino hydrogen atoms has been replaced by a. propyl radical and that said amine is free from any radical containing more than three carbon atoms; said amine salt being obtained from water-soluble, .non-hydrophobe, petroleum sulfonic acid of the green acid type.

2. A process for resolving petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier comprising a water-insoluble salt of monopropylamine; said amine salt being obtained from water-soluble, non-hydrophobe, sulfonic acid of the green acid type.

3. A process for resolving petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier ing the emulsion to the action of a demulsifier comprising a water-insoluble salt of tripropylamine; said amine salt being obtained from water-soluble, non-hydrophobe, sulfonic acid of the green acid type.

MELVIN DE GROOTE.