US3540866A - Fuel oil-water composition containing metal oxide - Google Patents

Description

United States Patent 3,540,866 FUEL OIL-WATER COMPOSITION CONTAINING METAL OXIDE Clark 0. Miller, Willoughby, Ohio, assignor to The Lubrizol Corporation, Wicklilfe, Ohio, a corporation of Ohio N0 Drawing. Filed June 22, 1964, Ser. No. 377,128 Int. Cl. C101 1/14 US. Cl. 44-51 11 Claims ABSTRACT OF THE DISCLOSURE A fuel oil-water composition containing a large amount of a metal oxide is useful as an additive in fuel oils and is especially effective to counteract the corrosive effects of vanadium present in fuel oils.

This invention relates to novel compositions and particularly to water-inoil emulsions. In a more particular sense, it relates to compositions which are useful as additives in fuel oils and especially to stable water-in-oil emulsions containing metal oxides.

Residual oil is an attractive fuel for industrial and marine use because of its availability and low cost. However, it has been recognized in recent years that such residual fuel oils contain sulfur and vanadium which cause corrosion and harmful deposits when burned in diesel engines, gas turbines, and other oil-fired burner applications such as steam boilers where high temperatures are involved. It is generally believed the high temperature corrosion is attributed principally to the vanadium. During combustion, the vanadium is converted to various undesirable compounds such as, for example, va' nadium pentoxide and the various metallic vanadates such as sodium vanadate. Vanadium pentoxide melts at a temperature of about 1275 F. and in the plastic or molten state, is sufiiciently reactive to corrode metals on contact. If the molten vanadium pentoxide or vanadates come into contact with the surface at some temperature below its melting point, the vanadium compound solidifies and ad heres to the metal surfaces forming deposits which are also objectionable since they reduce the efficiency of the engine. Parts which are affected include such items as nozzles in a gas turbine, valves, piston heads, flame rings, in diesel engines, and superheater tubes and boiler tubesupport plates in boilers using steam or mercury.

The problems raised by the presence of vanadium in the desirable fuel oils have been approached from different directions in' the past. Attempts have been made to develop corrosion-resistant alloys or coatings. Attempts have also been made to develop economical methods for removing vanadium from the fuel and to develop fuel additives to overcome the corrosion and deposition of the vanadium by-products. Some of these attempts have failed primarily because vanadium is not easily removed from fuel oils. However, vanadium can be rendered harmless by adding certain metallic elements to the fuel. These metals react with the vanadium during combustion to produce dry, non-reactive, non-adherent ash materials. Magnesium, calcium, strontium, and barium compounds are examples of such metals. For example, magnesium results in dry physical mixtures of magnesium vanadates, sulfates, and oxides. In some instances, these metals have been introduced into fuel as chemical slurries or as powdered mixtures. The use of slurries suffers the disadvantage that they must be agitated before using in order to suspend the metallic oxide so that the proper amount of metallic oxide will be added to the fuel oil. Also, metal oxides have a tendency to form clumps which are not dispersable. The addition of powdered metal oxides to 3,5 1,866 Patented Nov. 17, 1970 fuel oils generally results in the undesirable precipitation of a considerable amount of the metallic oxide.

Accordingly, it is an object of this invention to provide an eificient and satisfactory method for incorporating metallic oxides in fuel oils.

It is another object of this invention to provide novel compositions.

It is another object of this invention to provide stable water-in-oil emulsions.

It is another object of this invention to provide emulsions having extended room temperature stability.

It is another object of this invention to provide emulsions suitable for use as additives for fuel oils.

It is another object of this invention to provide a fuel oil additive composition to limit the corrosive effects of vanadium which is present in fuel oils.

These and other objects are accomplished in accordance with this invention by providing a composition consisting essentially of from about 1 to 60 parts of an oxide of a metal selected from the class consisting of magnesium, calcium, strontium, and barium, from about 10 to parts of a fuel oil, from about 1 to 20 parts of water, and from about 1 to 10 parts of a dispersing agent.

The water-in-oil emulsions of this invention have been found to be useful as additives for fuel oils containing vanadium since the metallic oxide present in the emulsion will effectively suppress corrosion resulting from the use of untreated fuel oils. These emulsions are especially useful as additives for heavy residuel type fuel oils which contain considerable amounts of vanadium.

The metallic oxides which are present in compositions of this invention include the oxides and hydroxides of magnesium, calcium, strontium, and barium. Generally, the oxides are preferred because of the increased stability of the emulsions formed therefrom but the metal may also be incorporated in the emulsion as the hydroxide. For example, a magnesium containing emulsion can be prepared utilizing magnesium hydroxide as well as magnesium oxide. In some instances, the metal oxide is converted to the metal hydroxide when brought in contact with the water of the emulsion.

The fuel oils which have been found useful in the preparation of the emulsions of this invention include all burnable oils including lubricating oils, the distillate fuel oils such as kerosene and the No. 1, 2, and 3 distillate fuels, and the residual fuels generally designated as Nos. 4, 5, and 6.

As mentioned previously, dispersions of metal oxides in fuel oils have suffered the disadvantage of instability, i.e., the metallic oxides do not remain suspended on standing. It has now been discovered that the precipitation of finely divided metallic oxides can be prevented when the mixture contains small amounts of water and a dispersing agent. Thus, a mixture consisting essentially of from one to 60 parts of one of the metallic oxides discussed above, from about 10 to 90 parts of a fuel oil, from about one to 20 parts of water, and from about one to 10 parts of a dispersing agent will form stable waterin-oil emulsions. The presence of the water is essential to the stability of the emulsion. In the absence of water, the above compositions are not stable and the metal separates from the liquid.

Any of the common dispersing agents may be utilized in the compositions of this invention. Especially preferred are the polyhydric alcohols and the alkali metal salts of sulfonic acids. The term polyhydric alcohols as used in the specification and claims are those preferably containing from 2 to 6 alcoholic radicals of which at least one is unsubstituted. The unsubstituted polyhydric alcohols include principally ethylene glycol, propylene glycol, sorbitol, and pentaerythritol. Higher molecular weight polyhydric alcohols are also useful. Examples of such alcohols include the various polyethylene glycols and polypropylene glycols. Partially acylated polyhydric alcohols, particularly those polyhydric alcohols having from 2 to 6 hydroxyl radicals of which at least one but not all are acylated with an aliphatic carboxylic acid having from about 8 to about 30 carbon atoms are also useful. Examples of such partially acylated polyhydric alcohols include glycerol mono-oleate, glycerol distearate, sorbitan monostearate, sorbitan didecanoate, sorbitan tristearate, and sorbitan mono-oleate. Sorbitan mono-oleate is particularly effective as a dispersant in the compositions of this invention.

The polyhydric alcohols may also contain ether linkages within their molecular structure. The ether-containing polyhydric alcohols may be obtained by dehydrating a polyhydric alcohol. Examples of such derivatives are sorbitan and mannitan. The ether-containing polyhydric alcohols may also be obtained by reacting a polyhydric alcohol with an epoxide. The epoxides are for the most part hydrocarbon epoxides and substantially hydrocarbon epoxides. The hydrocarbon epoxide may be an alkylene oxide or an aryl-alkylene oxide. The arylalkylene oxides are exemplified by styrene oxide, para-ethylstyrene oxide and oxide para-chlorostyrene oxide. The alkylene oxides include principally the lower alkylene oxide such as ethylene oxide, propylene oxide, 1,2-butene oxide and 1,2-hexene oxide. The substantially hydrocarbon epoxide may also contain polar substituents. The polar substituent is usually a halo radical such as chloro, fluoro, bromo, or iodo; an ether radical such as methoxy or phenoxy; or an ester radical such as carbomethoxy. Example of such epoxides include epichlorohydrin and butyl 9,10-epoxystearate. The number of ether linkages in the product is determined by the amount of epoxide added. Thus, it is possible to react a polyhydric alcohol such as sorbitol with 1, 2, 3 or more equivalents of an epoxide such as propylene oxide.

The polyhydric alcohols contemplated for use in the composition of this invention may also be ether-containing acylated polyhydric alcohols. These may be prepared by a number of methods. A polyhydric alcohol may be dehydrated and subsequently acylated or an alcoholic radical may be acylated first followed by dehydration of other alcoholic radicals. As mentioned previously, the other linkage may be also introduced by the reaction of an epoxide with the polyhydric alcohol either before or after acylation. Examples of ether-containing acylated polyhydric alcohols include polyoxyethylene sorbitan mono-oleate, polyoxyethylene sorbitan tristearate, polyoxyethylene glycerol distearate, polyoxypropylene sorbitan dilinoleate, and polyoxypropylene pentaerythritol mono-oleate.

Also useful as dispersing agents in the compositions of this invention are the oil-soluble metal sulfonates and particularly the oil-soluble alkali metal sulfonates and ammonium sulfonates. Suitable sulfonates include the salts of mahogany sulfonic acid which is prepared by the sulfonation of lubricating oils and similar hydrocarbon materials with fuming sulfuric acid as is well known in the art. The sulfonates can also be derived from relatively pure alkyl aryl sulfonic acids having from about 10 to 30 carbon atoms per molecule. For example, sulfonated products of alkylated aromatics such 4 alkali metal or ammonium salts of mixtures of such alkyl aryl sulfonic acids.

The stability of the emulsions is further related to the particle size of the metallic oxides. When the fuel oil of the emulsion is a light distillate fuel oil such as kerosene, a particle size of about 0.1 to 10 microns is desirable. Although larger particles tend to separate from kerosene emulsions, emulsions prepared with heavier residual fuel oils can tolerate particles up to 30 or =microns in diameter.

Although the compositions of this invention contain from about 1 to parts of a metal oxide, the most desirable emulsions are those containing large amounts of the metal oxide since it is the metal in these emulsions that is the active ingredient in treating vanadium containing fuel oils. Generally, the water-in-oil emulsions of this invention will contain from about 10 to 50 parts of the metallic oxide, from about 20 to 60 parts of a fuel oil, from about 3 to 10 parts of Water, and from about 1 to 10 parts of a dispersing agent.

The preferred emulsions of this invention will contain from about 40 to 50 parts of the metallic oxide, from about 40 to 50 parts of a fuel oil, from about 4 to 7 parts of water, and from about 3 to 6 parts of a dispersing agent.

The following examples illustrate the methods for preparing the compositions of this invention: (parts are by weight unless otherwise indicated).

EXAMPLE 1 To 200 parts of kerosene there is added 20 parts of an ammonium salt of an alkyl aryl sulfonic acid, predominately dodecyl benzene sulfonic acid and the mixture is stirred. Water (25 parts) is added followed by the addition of 50 parts of magnesium oxide. The mixture is stirred vigorously for a period of 5 minutes resulting in a stable water-in-oil emulsion.

EXAMPLE 2 To 20 parts of kerosene there is added 2.5 parts of Water, 5.0 parts of magnesium oxide and 2 parts of an oil solution containing 60% by weight of the sodium salt of an alkyl benzene sulfonic acid having a molecular weight of 450. The mixture is stirred vigorously resulting in a formation of a stable emulsion.

EXAMPLE 3 To one-half of the emulsion of Example 2 there is added 3.7 parts of magnesium oxide with vigorous stirring. The resulting emulsion contains 26% magnesium oxide and is very stable.

EXAMPLE 4 Sorbitan mono-oleate (4.7 parts) is added to 47 parts of No. 1 fuel oil and the mixture is stirred for 20 minutes at 30 C. Water (5.9 parts) is added to the mixture followed by the addition of 42.4 parts of magnesium oxide over a period of 50 minutes at a temperature of 32 C. The mixture was mixed with circulation through a dispenser for 6.5 hours at 32 C. The resulting emulsion has a specific gravity at 60 F. of 1.2556 and a magnesium content of 24%.

EXAMPLE 5 A mixture of 66 parts of kerosene, 8.2 parts of water, and 6.6 parts of the ammonium sulfonate of Example 1 is prepared and mixed thoroughly by vigorous stirring. To this mixture there is added 19.7 parts of magnesium hydroxide over a period of 5 minutes followed by an additional period of stirring for 2 minutes. The resulting emulsion is stable and contains approximately 8% magnesium.

EXAMPLE 6 The emulsion of Example 5 is further stabilized by the addition of 0.2 part of a hydrated magnesium silicate gelling agent having a particle diameter of approximately 1 micron.

EXAMPLE 7 Sorbitan mono-oleate (6 parts) is added to 60 parts of kerosene and the mixture is stirred for 5 minutes in a Waring blender. Water (7.5 parts) is added and the mixture is blended an additional 5 minutes followed by the addition of 54 parts of magnesium oxide. The blender is maintained at high speed for an additional 5 minutes resulting in the formation of a stable emulsion having a specific gravity at 60 F. of 1.2564 and a magnesium content of 23.98%. The size of the particles in this emulsion ranged from 0.5 to 8 microns in diameter.

EXAMPLE 8 Sorbitan monostearate (8 parts) is added to 42 parts of a No. 5 residual fuel oil with stirring. Water (15 parts) is added followed by the addition of 30 parts of magnesium oxide. The mixture is stirred vigorously an additional 5 minutes resulting in the formation of a stable emulsion.

EXAMPLE 9 The procedure of Example 8 is repeated using 5 parts of sorbitan monostearate, 80 parts of No. 5 residual fuel oil, 5 parts of water and 5 parts of magnesium oxide.

EXAMPLE 10 The procedure of Example 8 is repeated except that 7 parts of sorbitan monostearate, 60 parts of No. 5 residual fuel oil, parts of Water, and 10 parts of magnesium oxide is mixed to form a stable emulsion.

EXAMPLE 11 The procedure of Example 4 is repeated except that the sorbitan mono-oleate is repeated except that polyoxyethylene sorbitan trioleate is used in lieu of the sorbitan mono-oleate.

EXAMPLE 12 The procedure of Example 4 is repeated except that sodium mahogany sulfonate is used in lieu of the sorbitan mono-oleate.

EXAMPLE 13 A mixture of 60 parts of No. 5 residual fuel oil, 15 parts of water, 7 parts of sorbitan monostearate, and 10 parts of calcium oxide is stirred vigorously to form a stable emulsion.

EXAMPLE 14 The procedure of Example 13 is repeated except that strontium oxide is used in lieu of calcium oxide.

EXAMPLE 15 The procedure of Example 13 is repeated except that barium oxide is used in lieu of calcium oxide.

The stability of the water-in-oil emulsions of this invention, i.e., the ability of the emulsion to retain the metal oxide in solution over an extended period of time is determined as follows. As noted previously in the preparation of the product of Example 4, the mixture was mixed with circulation through a disperser for 6.5 hours. Several samples were collected during this period and at the termination of the circulation. These samples were allowed to stand for one month. A few milliliters of the emulsion samples were collected by placing a pipet in the sample and extracting a small amount of the emulsion at different levels. These were then placed in separate crucibles which had been fired and tared. The crucibles containing the magnesium emulsions were then weighed and heated to drive off all of the liquid (until the vapors caught fire). The crucible and its contents were cooled and reweighed. The amount of solid in the emulsion at this time was determined according to the following calculation.

SNle Weght 100: percent solids TABLE I Percent sloids retained Sample Sample Pore nt weight weight Percent M g0 Sample identity wet (g.) dry (g.) solids suspension Baseline 1 9.15 3.81 41. 7

41. 3 8. 62 10. 57 41. 6 100 Final product 10. 57 4. 40 41. 7 100 S l t k ft 10. 26 4. .26 41. 5 100 amp 0 a en a er 1 hour of circulation g i s throlugth ldisperser 2 amp e a on after 0.5 hour of circulation l g through disperser 3 1 Final product obtained in Example 4 (mixed well before sampling).

2 Sagnple collected three inches from top of fluid after standing one mon 3 Sample collected one inch from top of liquid after standing one month.

The viscosity of some of the emulsions prepared in accordance with this invention will often increase on standing for a few days. Although this results in a more viscous emulsion, the emulsion remains quite fluid and the increased viscosity aids in maintaining the metallic oxides in the emulsion. The emulsion prepared in Example 7 is an example of an emulsion which undergoes a slight viscosity increase for a short period after preparation. The change in viscosity over a period of 13 days at F. was observed and the results are recorded in Table II. These results indicate that the viscosity does not continue to increase but levels off after a period of a few days resulting in a more stable emulsion.

TABLE II Change in viscosity of emulsion Time, days: Brookfield viscosity (cks.) O 240 l 324 2 364 3 410 7 445 8 493 9 485 10 488 13 468 The emulsions of this invention are primarily useful as additives for residual fuel oils which contain substantial amounts of vanadium. The amount of vanadium found in residual fuel oils varies from about 5 to about 500 parts of vanadium per million parts of fuel oil depending on the source of the crude oil and the particular fraction. The corrosion of metallic pieces by vanadium can be reduced by adding metals such as magnesium, calcium, strontium, and barium which combine chemically with the vanadium to form noncorrosive compounds which do not adhere to the metal surfaces. The emulsions of this invention provide a convenient and inexpensive method of introducing the needed metal into the fuel. Addition of a stable emulsion is not only desirable because of the ease of the operation, but also because the emulsion mixes well with residual fuels thereby dispersing the metal throughout the fuel.

It is generally accepted that a metal to vanadium ratio of about 3:1 is desirable. Thus, the amount of emulsion to be added to a fuel oil is determined by considering the amount of metal in the emulsion and the amount of vanadium in the fuel being treated. The emulsions of this invention will generally contain from about 15% to about 35% of metal. Accordingly, for example, when a heavy fuel oil (density of about 1.00) containing about 200 parts of vanadium per million parts of fuel oil is treated, approximately one gallon of the product of Example 4 (containing 24% magnesium) is sufiicient to treat about 510 gallons or 16 barrels of fuel oil.

What is claimed is:

1. A homogeneous emulsion consisting essentially of from about 1 to 60 parts of an oxide of a metal selected from the class consisting of magnesium, calcium, strontium, and barium, from about to 90 parts of a fuel oil, from about 1 to 20 parts of water, and from about 1 to 10 parts of a dispersing agent.

2. The homogeneous emulsion of claim 1 wherein the oxide is magnesium oxide.

3. The homogeneous emulsion of claim 1 wherein the dispersing agent is selected from the group consisting of polyhydric alcohols and alkali metal salts of sulfonic acids.

4. A homogeneous emulsion consisting essentially of from about 10 to 50 parts of an oxide of a metal selected from the class consisting of magnesium, calcium, strontium, and barium, from about 20 to 60 parts of a fuel oil, from about 3 to 10 parts of water, and from about 1 to 10 parts of a dispersing agent.

5. The homogeneous emulsion of claim 4 wherein the oxide is magnesium oxide.

6. The homogeneous emulsion of claim 4 wherein the dispersing agent is selected from the class consisting of polyhydric alcohols and alkali metal salts of sulfonic acids.

7. The homogeneous emulsion of claim 4 wherein the dispersing agent is a partially acylated polyhydric alcohol.

8. The homogeneous emulsion of claim 7 wherein the partially acylated polyhydric alcohol is sorbitan monooleate.

9. A homogeneous emulsion consisting essentially of from about to parts of magnesium oxide, from about 40 to 50 parts of a fuel oil, from about 4 to 7 parts of water, and from about 3 to 6 parts of a partially acylated polyhydric alcohol.

10. The homogeneous emulsion of claim 9 wherein the partially acylated polyhydric alcohol is sorbitan monooleate.

11. The homogeneous emulsion of claim 9 wherein the partially acylated polyhydric alcohol is sorbitan monostearate.

References Cited UNITED STATES PATENTS 2,671,758 3/ 1954 Vinograd et al. 252-25 827,139 7/1906 Browne et al. 4451 1,440,356 12/ 1922 Morrell 44-51 1,701,621 2/ 1929 Kirschraun 445 1 3,078,663 2/1963 Rocchini et al.

FOREIGN PATENTS 544,038 7/ 1957 Canada. 705,176 3/ 1954 Great Britain.

PATRICK P. GARVIN, Primary Examiner Y. H. SMITH, Assistant Examiner US. Cl. X.R.