US2807527A - Petroleum distillate compositions containing fatty oil pitches - Google Patents

Description

Patented Sept. 24, 1957 PETROLEUM DISTILLATE COIVIPOSITIONS CON- TAWING FATTY OIL PITCHES Charles T. Brown and Robert L. Dinsmore, Long Beach, and Wendell F. Deeter, Bellflower, Calif., assignors to Richfield Oil Corporation, 'a corporation of Delaware No Drawing. Application February 4, 1954, Serial No. 408,287.

5 Claims. (Cl. 44-61) This invention relates to liquid petroleum hydrocarbons having added thereto small but effective amounts of corrosion inhibiting substances which are residues from refining. V

It is well known in the art that rusting or corrosion may occur on steel or iron surfaces in contact with hydrocarbons and water. All types of liquid hydrocarbon products including gasoline, kerosene, thinners, stove oil, diesel oil and residual fuel oil, exhibit this corrosive effect. Corrosion of ferrous metals by le'aded gasoline is particularly severe. Water is almost always present in association with hydrocarbons in storage, blending and distribution systems. Water is frequently introduced into petroleum systems with the hydrocarbon itself either in the dissolved or suspended state, and in addition may be intentionally introduced as a bottom seal for a storage tank. The Water may even be formed in situ by condensation from the air in a tank due to changes in atmospheric conditions. Further it is common practice to use water as a follower for a particular petroleum stock in a pipe line, to clean and'flushlines and tanks with Water and to use water in the oil tanks of ships as ballast orfor cleaning purposes.

It is obvious that rusting at any point in the manufacturing, distribution or terminal system represents a considerable monetary loss due toextra expense for cleaning Under severe conditions of "corrosion, it may even be necessary to replace the expensive equipment.

and repair of these systems.

Furthermore, rust formed in one part of a fuel system is frequently transported with the fuel to other parts. The rust may plug screens and filters, re-

sulting in inefiicient operation or in some cases, complete stoppage. Rust in these systems is particularly detrimental Where parts are machined to close tolerances, due to excessive wear caused by the foreign material.

In recent years, in addition to the corrosion problems mentioned above, a new source of greater difliculty has arisen in connection with the use of hydrocarbon solvents for various chemicals which tend to accelerate corrosion.

Thisproblem has been particularly troublesome in the case of DDT-hydrocarbon solvent systems. Another corrosion problem has arisen in the wood treating industry "where it is customary to use a petroleum solvent for pentachlorophenol. This solution is often subjected to a wide range of temperatures, from atmospheric to 250 F. and

to pressures ranging from :15" of mercury vacuum to 150 lbs. per square inch gauge. Further, the presence of water, steam and air is usual. Under these conditions, abnormal corrosion may occur due to the presence of the chlorinated compound andthe wide variation in operating conditions. Corrosion in these systems tends to shorten greatly the useful life of the equipment.

In the present-invention, liquid petroleum hydrocarbon systems are inhibited against corrosion by having added --thereto a rust or corrosion inhibitor which is afatty acid pitch which is the residue from the-refining of a fatty oil, e. g., of animal, vegetable-or fish origin; The pitches which are useful are soluble in the liquid petroleum hydrocarbon at least to an extent suificient to afford the desired inhibiting effect. Mixtures of these pitches are also effective to inhibit rust and corrosion. The fatty acid pitches employed in our invention are in general, viscous, high-boiling substances which are variously described in the art as residues, foots, still-bottoms, break materials, acidulated dewatered soapstocks and pitches.

These pitches are commercially available materials which are produced in conventional fatty oil refining operations. For instance, acidulated dewatered soapstocks are derived from the fatty oil through alkali refining of the oil e. g., see U. S. Patents Nos. 2,100,274 to 2,100,277. The other refining methods affording the desired pitches are acid refining, steam refining or distillation, desliming and degumming methods including hydration and heat treatment and liquid-liquid extraction procedures. All of these methods are well known operations, many of which are described in U. S. Patents, e. g., see Nos. 2,150,732 and 2,201,063. Still-bottoms residues useful in this invention may also be obtained by the splitting of glycerides. Glycerides in raw fatty oils are split with acid-type catalysts and the valuable products removed by vacuum distillation at elevated temperatures. The mixed vegetable oil pitch referred to in Table I below was obtained as a bottoms product in the splitting and vacuum distillation of mixed soya and cottonseed oils.

The vegetable pitches useful in this invention can be obtained as by-products in the processing of cottonseed, flaxseed, soya bean, tung, coconut and other oils of vegetable origin. The marine pitches employed are those obtained as by-products in the processing of Whale oil, menhaden oil, cod oil, fish liver oils of any kind and other oils of fish or marine origin. The animal pitches utilized are derived as by-products in the refining of fats and other materials of animal origin. It is the residues from the processing or distillation of these fatty oils, irrespective of their source, which are useful in this invention.

The fatty oil pitches useful in this invention are difficult to define chemically due to differences in source and changes which occur during processing. They can generally be characterized as a mixture of glycerides, unsaponifiables, fatty acids and esters. The pitch may be polymerized to varying degrees depending on processing conditions, i. e., a mixed vegetable and animal pitch may contain approximately 35% glycerides and polymerized material, 25% unsaponifiables and 40% fatty acids and esters. Table I below indicates the approximate composition and boiling range of several pitches which are useful in this invention. The pitches were distilled under vacuum and the values for the distillation temperatures corrected to atmospheric pressure.

The effectiveness of .the fatty oil pitches appears to be due to the fact that these materials preferentially wet metal surfaces, forming a thin, perhaps monomolecular film thereon which is protective against the attack of corrosive materials in contact with the surfaces. Thepitches useful in this invention are effective inhibitors for petroleum products such as gasoline, naphthas, thinners, kerosene,

2,so7,527 v i stove oil, diesel oil, lube oils and residual fuel oil, and are TA I useful in any type of manufacturing, distribution or con- Rating: 7 t Percent rust sumer fuel system. Our inhibitors are particularly use- A e None. fulvin systemshandling light distillates. By. light .dis- B++ Trace.

rtillates we mean petroleum distillates of a viscosity not B+ Less than 5.

exceeding that of gas oil. The inhibitingrnaterials are B 5-25. inexpensive since they are, for the most part, ,by-products. C 50.

, Thepropertiesof the pitches may vary widely without D .4 50-75- afiecting their value as corrosion inhibitors. Also, pitches i E 7 .from diiferent sources are effective either singly or as a 10 Th effect of pitch concentration on the rust rating of 1 mixture. The table below listsaselection of pitches which a leaded ethyl gasoline is shown in the table below.

i are among those elfective for the purpose of this inven- The pitch used was a mixed animal-vegetable pitch having tion. a saponification number of 180; a

Table II Properties of typical pitches 1 Sp. gr. at Acid num- Sap. num- Viscosity, Pitch source Type 60 F. ber ber S. S. U. V., ,7 p at210F.;.

Cottonseed 1.01 38 103 2, 000. s .97 37 139 403 .92 87 183 52.2 1.00 99 161 701 Fish 93 109 197 46. 7 Vegetable and animal 982 9. 4 180 r 118 Fish and .97 39 144 456 (S. S. U. V. seconds Saybolt Universal viscosity.)

For the purposeof this invention, the pitch can be TABLE IV used in the form derived from the fatty oil refining prop cedures, or can be diluted with a solvent, or blended with g i v ibSJM bbls" Rust S other materials for facility in handling. For example, a B+ mixed pitch of vegetable and animal origin having a Say- 7 3 V bolt Universal viscosity at 210 F. of 11.8 seconds may 40 5 I B++ be diluted with 2 parts by volume of Stoddard solvent to one part of pitch, thus reducing the viscosity to 87 seconds 1, Saybolt Universal at 60 F. These pitches prevent cor- The effestlveness of QOTTOSlOB lnhlbltors 0f l l rosion by forming a film on the metal surface to be pro- P 9 not PP i 50111126 0f the vl'esldlleS tected thus preventing contact'with water, dilute acids pltqhes used- T1115 faclf 1S lllusfl'ated y b below and other reactive materials. The pitches are petroleum shows the f I'atmg Obtamed b 115mg P 9 from oil-soluble and can be diluted with any appropriate solvent l l-l P- 111 a leaded gasoline at a concentration such as petroleum thinners, aromatics or alcohols. V of D 1000 e The effective concentrations of fatty oil pitches for in- V I B' E V hibition of corrosion are generally very low. This fact .p t rating is advantageous because in the concentrations used the e 'materials do not affect the other properties or specifica- Fish e tlons of the product. In general effectlveconcentrations 7, Vegetable (com'mseed) v of pitch range from as httle as 1, lb. per 1000 barrels of vegetable (soya) the liquid petroleum hydrocarbon to be treated to as much Animal (Ebony fat: as 5 percent by we1ght. Mostof the pltches are dark in Animal (Ebony fat #40) v color WhlCh limits their use 1n light drstillates such as Mix d vegetable & animal 1(140 Sap. No.) B++ gasoline to 1 lb. to 15 lbs. per 1000 barrels. In lube 0118, Mixed vegetable & animal (180 San B however, the product color is not so lmportant and con- Mixed fish and cbentratrlons iot p tch as high as 5 percent by welght can 0 yegetable' u oil) B eemoe. a

The f llowing specific examples of the use ofthe intests f also been 1 w? q m t the hibiting materials of our invention in various petroleum i f s' plt-ch as FOUOSwnJPmbHOIFH leaded products will serve to illustrate the invention. The rust gasohn? cgncentrailon', mixed: ammalwegfi ratings referred to in the tables were determined by a tablepltch havmg'a sagomficanon number of modification of ASTM method n-sss-szr which is as the resultshwn Table Q A follows: Gasoline (350 ml.) containing inhibitor is poured TABLE V1 .into a 4-00 ml. beaker, a olished steel rod is inserted V V f r f and'the gasoline stirred for aperiod of 30minutes. At M bbls: 1 Rust mung the end of that time, 50 ml. of hydrocarbon is withdrawn 1 g I f Y E and 30 ml. of water added. Stirring is continued for 3 /2 2V V C hours. At the end of the 3 /2 hour period, the steel rod .2 i B is removed and the percentage of rusted surface is esti- 1 I I B+ mated. The testis conducted at room temperature in The static test is run using a piece of ASTM grade the presence of air andthe ratings; are madeas follows: p

1010 steel, 1%" x 5" x 1%",which has been sanded to remove all traces of rust and corrosion and then degreased by washing with benzene and acetone, followed by heating at 230-250 F. for thirty minutes. The strip is placed in a 6-02. bottle containing 150 ml. of the product to be tested and shaken for 30 minutes. Fifteen m1. of distilled water is added and shaking continued for 10 minutes more. The bottle is placed in aninclined position to prevent the end of the steel strip from remaining in direct contact with the main body of water. Before placing in the inclined position, the bottle is generally shaken to suspend water and leave droplets on the top surface of the strip. The bottle is left undisturbed for 24 hours, then is gently shaken and turned over with the other side of the metal strip facing upwards. After another 24 hours, the steel strip is rated according to the scale employed for the modified ASTM method D-665- 521 tests.

The pitches of this invention in addition to being effective corrosion inhibitors are also stabilizing agents for tetraethyl lead in gasoline against the action of sunlight. It is common knowledge that commercial gasoline now on the market containing tetraethyl lead becomes cloudy when exposed to direct sunlight, due to the decomposition of the lead compound. When modern gasoline pumps are used, the decomposition of tetraethyl lead is not par ticularly troublesome because the gasoline is not exposed to direct sunlight. This is not true, however, in old style gasoline pumps which frequently have a l-gallon glass bowl which is exposed to sunlight. When gasoline is allowed to stand for any length of time in the old style pumps, a cloudy precipitate is likely to form. The stabilizing elfect of our inhibiting pitches has been shown by exposing samples of leaded gasoline with and without the inhibitor in clear glass bottles to direct sunlight. The gasoline tested contained approximately 2 cc. of tetraethyl lead per gallon. It was noted that the first decomposition of lead in the uninhibited sample occurred after 3% hours, the initial decomposition of lead compound in the sample inhibited with a vegetable-animal pitch in a concentration equivalent to 2 lbs. of pitch per 1000 barrels was 13 /2 hours. Still bottoms from the distillation of soya beam oil and cottonseed oil were found to exhibit similar properties of stabilization for tetraethyl lead in gasoline.

A further example of the results obtained by the corrosion inhibitor of this invention is as follows: The test consisted of incorporating a mixed vegetable oil pitch at a concentration of 5 lbs. per 1000 barrels in a stove oil with a neat rust rating of E. The rust rating of the inhibited sample was B++.

An example of the efiectiveness as corrosion inhibitors of the pitches of this invention when used in jet fuel is illustrated by the results shown in Table VII.

TABLE VII Concentra- Rust Pitch tion,L lb./ rating M bbls.

The pitches of this invention are also effective as corrosion inhibitors in lube products at concentrations as low as 01% to as much as 5% by weight. Tests made with a western refined turbine oil gave the results shown in Table IX below. The ratings in Table IX were determined by ASTM method D665-52T, which is a tentative method for determining the 'rust-preventingcharacteristics of steam turbine oil in the presence of water. The procedure is the same as the modified method de scribed above for testing gasoline, except that the sample is run in a controlled temperature bath at 140 F. for a period of 24 hours after the addition of water. A passing rating requires that there be no visible rust spots on a steel test specimen.

TABLE IX Concentra- Pitch source Type tion, wt. Rust rating percent 0.2 Passes 0.5 Do. 0.2 Do. 0.2 Do. 0.5 Do.

Certain pitches due to their dark color may not in certain instances be suitable for use at the required concentrations in certain products. There are, however, other pitches such as tall oil pitch which are light enough in color to be useful at the required concentrations in these special products.

It has been found that concentrations as low as .0l% by weight of the corrosion inhibitors of this invention frequently provide as much as 98% corrosion protection when added to special solvents used as carriers for other chemicals; however, it is occasionally necessary to use concentrations as high as 1% of corrosion inhibitor for satisfactory results. As a specific example of this application of our invention, a small quantity of inhibitor was added to 200 cc. of a petroleum hydrocarbon solvent containing 5% by weight of pentachlorophenol. This mixture was transferred to an oxygen stability tube and 2% water added. A polished steel strip 1" x 10" and a block of fir, /2" x x 3" were then inserted into the tube. The tube was placed in the bomb of a conventional oxygen stability apparatus and kept under 100 lbs. of oxygen pressure at a temperature of 212 F. for three hours. The bomb was then depressured and the tube removed and allowed to stand for 16 hours. The steel strip was inspected for rusting and the results reported In practice, the additives of this invention are usually present in such small amounts that their presence is difficult to detect in petroleum products. It has been iqundthatq llt siqn pr t on fl y the a t v ofthis invention is due, not only to one, but to many q mriqn nts, o h itchrwAr amp e o i d m vegetable pitch, saponification No. 180, wasvextrac-ted with acetone 'and both the extract and the rafiinate phases;

tested in a sample: of leaded gasoline having a neat rust rating of ;E.""B0th phases" of the pitch gave a rating of B++ .when used at a concentration of two lbs. per" l000'bbls.of gasoline. p We claim: 1 1 A composition consisting essentially of a lightpetroleum distillate having incorporated therein a soluble fatty oil pitch in an amount effective as a corrosion inhibitor, said amount being-from 1 to 15 pounds per thousand barrels of said distillate.

2. The composltlonof claim 1 wherein said distillate is gasoline.

' .1 3. Thecomposition of claim 1 wherein said distillate is I a leaded gasoline.

4.; A composition consisting essentiallyl of light incorporated thereinfa 'soluble fatty oil pitch in anamount efiectiveto inhibit corrosion. and to lead, barrels of said distillate.

stabilize jtetraethyl sjc fhe file of this patent I UNITED sTAT s PAT TS 2,014,235 Lowry Sept. 10, 1935" 2,339,796 'Musher ..L Jan. 25,1944 2,596,065 Brabets ;;.l lMay'6, 1952 2,668,138 Walker et a1. Feb.'-2,:1954. 2,671,761 Kalinowski et al Mar. 9,1954

2338-2347, December 1948.

lgtoj '15 pounds, per thousand barrels-c said amount beinglfrorn 1 to15 pounds perthousand White et a1. Aug/17,1954? J 7 OTHER REFERENCES 5 Industrialand Engineering Chemistry, v01. 4() pages

Claims (1)

1. A COMPOSITION CONSISTING ESSENTIALLY OF A LIGHT PETROLEUM DISTILLATE HAVING INCORPORATED THEREIN A SOLUBLE FATTY OIL PITCH IN AN AMOUNT EFFECTIVE AS A CORROSION INHIBITOR, SAID AMOUNT BEING FROM 1 TO 15 POUNDS PER THOUSAND BARRELS OF SAID DISTILLATE.