| 1. | A composition for emulsifying a petroleum product that has been spilled upon a portion of the earth's surface, said composition comprising : (a) a nonionic, primary surfactant comprising an ethoxylated sorbitol oleate ; (b) a nonionic, secondary surfactant capable of stabilizing and solubilizing said primary surfactant such that said composition has a hydrophilic/lipophilic balance between about 12. 0 and about 1. 5 ; and (c) water. |
| 2. | The composition of claim 1 wherein the primary surfactant contains about moles to about 45 moles of ethylene oxide and comprises from about 45 to 90 weight percent of the composition for emulsifying a petroleum product. |
| 3. | The composition of claim 1 wherein the primary surfactant is ethoxyiaied sorbitol septaoleaie. |
| 4. | The composition of claim 1 wherein the primary surfactant is ethoxylaied sorbiiol sepiaoleate that contains about 35 moles to about 45 moles ofethylene oxide. |
| 5. | The composition of claim 1 wherein the secondary surfactant has a hydrophilic/lipophilic balance of about 10 to about 17. |
| 6. | The composition of claim 1 wherein the secondary surfactant is selected from the group consisting of linear ethoxylated secondary alcohol, polyoxyethylene aryl ether and ethoxylated sorbitan monolaurate and contains about 7 moles to about 26 moles of ethylene oxide and comprises about 20 to about 36 weight percent of said composition. |
| 7. | The composition of claim 1 wherein the secondary surfactant is linear ethoxylated secondary alcohol that contains about 7 moles to about 11 moles of ethylene oxide, has a hydrophilic/lipophilic balance of about 10 to about 15 and comprises about 36 weight percent of said composition. |
| 8. | The composition of claim 1 wherein the secondary surfactant is polyoxyethylene aryl ether that has a hvdrophilic,/lipophilic balance greater than about 15. 5 and comprises about 20 weight percent of said composition. |
| 9. | The composition of claim 1 wherein the secondary surfactant is ethoxylaied sorbiian monolaurate that contains about 15 moles to about 26 moles of ethylene oxide, has a hvdrophilic, lipophilic balance of about 15 to about 17 and comprises about 26 weight percent of said composition. |
| 10. | The composition of claim 1 that further comprises about 0. 05 to about 0. 0 weight percent water. |
| 11. | The composition of claim 1 that further comprises about 1. 0 to about 4. 0 weight percent emulsionstabilizing agent. |
| 12. | The composition of claim I that further comprises a polyethylene glycol component having a molecular weight from about 200 to about 400. |
| 13. | The composition of claim I diluted with locally available water. composition for emulsifying a petroleum product that has been spilled upon a portion of the earth's surface, said composition comprising : (a) a nonionic. primary surfactant composition comprising : (1) a first ethoxylated sorbitol oleate ; and (2) a second ethoylated sorbitol oleate ; (b) a nonionic, secondary surfactant capable of stabilizing and solubilizing said primary surfactant composition such that the composition for emulsifying a petroleum product has a hydrophilic/lipophilic balance between about 12. 0 and about 13. |
| 14. | and (c) water. |
| 15. | The composition for emulsifying a petroleum product of claim 14 wherein the first ethoxylaied sorbiiol oleate contains about 35 moles to about 45 moles of ethvlene oxide and comprises about 5 to about 50 weight percent of said composition for emulsifying a petroleum product. |
| 16. | The composition for emulsifying a petroleum product of claim 14 wherein the first ethoxylaied sorbitol oleate is ethoxylaied sorbitol septaoleate. |
| 17. | The composition for emulsifying a petroleum product of claim 14 wherein the first ethoxylated sorbitol oleate is ethoxvlated sorbitol septaoleate that contains about 35 moles to about 45 moles of ethylene oxide and comprises about 45 to about 50 weight percent of said composition for emulsifying a petroieum product. |
| 18. | The composition for emulsifying a petroleum product of claim 14 wherein the second ethoxylated sorbitol oleate contains about 40 moles to about 50 moles of ethvlene oxide and comprises about 9 to about 10 weight percent of said composition for emulsifying a petroleum product. |
| 19. | The composition for emulsifying a petroleum product of claim 14 wherein the second ethoxylated sorbitol oleate is selected from the group consisting of et, hoxvlated sorbitol trioleate and ethoxylated sorbitol hexaoleate. |
| 20. | The composition for emulsifying a petroleum product of claim 14 whe : ein the secondary surfactant has a hydrophilic/lipophilic balance of about 10 to about 17. |
| 21. | The composition for emulsifying a petroleum product of claim 14 wherein the secondarv surfactant is selected from the group consisting of linear ethoxylated secondary alcohol, polyoxyethylene aryl ether and ethoxyiaied sorbitan monoiaurate and contains about 7 moles to about 26 moles of oxide and comprises about 0 to about 36 weight percent of said composition for emulsifying a petroleum product. |
| 22. | The composition for emulsifying a petroleum product of claim 14 wherein the secondary sunaciam is linear ethoxylated secondary alcohol that contains about 7 moles to about 11 moles of ethylene oxide, has a hydrophilic/lipophilic balance of about 10 to about If and comprises about ó weiiht oerceni of said composition for emulsifying a petroleum product. |
| 23. | The composition for emulsifying a petroleum product of claim 14 wherein the secondary surfactant is polyoxyethylene aryl ether that has a hydrophilic, ilipophilic balance Creater than about 15.5 and comprises about 20 weight percent of said composition for emulsifying a petroleum product. |
| 24. | The composition for emulsifying a petroleum product of claim 14 wherein the secondary surfactant is ethoxylated sorbitan monolaurate that contains about 1 moles to about 26 moles of ethylene oxide, has a hydrophilic ! lipophilic balance of about 15 to about 17 and. comprises about 26 weight percent of said composition for emulsifying a petroleum product. @ The composition for emulsifying a petroleum product of claim m 14 that further comprises about 0. 05 to about 30. |
| 25. | 0 weight percent water. |
| 26. | The composition for emulsifying a petroleum product of claim 14 that further comprises about 1. 0 to about 4. 0 weight percent emulsion stabilizing agent. |
| 27. | The composition for emulsifying a petroleum product of claim 14 that further comprises a polyethylene glycol component having a molecular weight from about 200 to about 400. |
| 28. | The composition of claim 14 diluted with locally available water. ^9,. A method for emulsifying a petroleum product that has been spilled uson a portion of me earth's surface, said method comprising contacting said petroleum product with a composition for emulsifying a petroleum product comprising : (a) a nomomc. primary surfactant composition comprising : (1) a first eloxylated sorbitol oleate ; and (9) a second ethoxylated sorbitol oleate ; (b) a nonionic, secondary surfactant capable of stabilizing and solubilizing said primary surfactant composition such that said composition for emulsifying a petroleum product has a hvdrophilic/lipophilic balance between about 12. 0 and about 13. ; and (c) water. |
| 29. | 50 The method of claim 29 wherein the first ethoxylated sorbitol oleate contains about 3 moles to about 45 moles of ethylene oxide and comprises about 5 to about 50 weight percent of said composition for emulsifying a petroleum product. |
| 30. | 01 The method of claim 9 wherein the first ethoxvlated sorbitol oleate is ethoxylated sorbitol septaoleate, 32. The method of claim 29 wherein the first ethoxylated sorbitol oleate is ethoxylated sorbitol septaoleate that contains about 35 moles to about 45 moles of ethylene oxide and comprises about 45 to about 50 weight percent of said composition for emulsifying a petroleum product. The method of claim 9 wherein the second ethoxvlated sorbitol oleate conrains about'0 moles to about 50 motes of ethyiene oxide and comprises about 9 to about 10 weight percent of said composition for emulsifying a petroleum product, The The method of claim 29 wherein the second ethoxylated sorbitol oleate is selected from the group consisting of ethoxvlated sorbitol trioleate and ethoxylated sorbitol hexaoleate. |
| 31. | 35 The method of claim 29 wherein the secondary surfactant has a hydrophilic/lipophilic balance of about 10 to about 17. |
| 32. | 36 The method of claim 29 wherein the secondary surfactant is selected from the group consisting of linear ethoxylated secondary alcohol, polyoxyethylene aryl ether, and ethoxylated sorbitan monolaurate and contains about 7 moles to about 26 moles of ethylene oxide and comprises about 20 to about 6 weight percent of said composition for emulsifying a petroleum product. |
| 33. | 37 The method of claim 29 wherein the secondary surfactant is linear ethoxvlated secondarv alcohol that contains about 7 moles to about 11 moles of ethylene oxide, has a hvdrophilic, lipophilic balance of about 10 to about ln and comprises about 36 weight percent of said composition for emulsirying a petroleum product. |
| 34. | 38 The method of claim 29 wherein the secondary surfactant is polvoxvethvlene arvl ether that has a hydrophilic/lipophilic balance greater than about 15. |
| 35. | 5 and comprises about 20 weight percent of said composition for emulsifying a petroleum product, >9 The method of claim 29 wherein the secondary surfactant is erhoxvhied sorbiian monoiaurate that contains about lo moles to about'6 moles of ethylene oxide, has a hydrophilic ; lipophilic balance of about 15 to about 17, and comprises about 26 weight percent of said composition for emulsifying a petroleum product. |
| 36. | The method of claim 9 further comprising employing about 0. 05 to about 30. 0 weight percent water in said composition. |
| 37. | The method of claim 29 further comprising employing about 1. 0 to about 4. 0 weight percent emulsionstabilizing agent in said composition. |
| 38. | The method of claim 29 further comprising employing a polyethylene glycol component having a molecular weight from about 200 to about 400 in said composition. |
| 39. | The method of claim 29 wherein the portion of the earth's surface is a body of water. |
| 40. | The method of claim 29 wherein the portion of the earth's surface is a portion of land. |
| 41. | The method of claim 9 wherein the composition for emulsifying a petroleum product is diluted with locally available water prior to contacting the petroleum product with said composition. |
| 42. | A cieanins aseni for removing hydrocarbon residues from container walls. machine tool paris. and concrete surfaces, said cleaning agent comprising : (a) a nonionic, primary surfactant composition comprising : (1) a first ethoxylated sorbitol oleate ; and (2) a second ethoxylated sorbitol oleate ; (b) a nonionic, secondary surfactant capable of stabilizing and solubilizing said primary surfactant composition such that the composition for emulsifying a petroleum product has a hydrophilic/lipophilic balance between about 12. 0 and about 13. 5 ; and (c) water. |
The present invention relates, in general. to compositions and meth- ods for dispersing petroleum spills, and for accelerating biodegradation of such petroleum spills. and especially those that have occurred upon a body of water or any other surfacé.
2. Statement of the Problem.
Crude petroleums, as well as many products derived from them, are shipped from oil-producing locations 10 on-consuming locations in ocean- going vessels having huge capacities. Accidents in which the hulls of such vessels are breached and their contents spilled can cause serious damage to the environment. Unforrunaieiy. such accidents are not at all uncommon.
Land and offshore oil \veils also can be a source of oil spills into ocean
waters. Oil spills from such accidents may quicklv spread over many square mixes of water surface. When they occur near, or drift to, shorelines, such spills are particularly destructive toward local wildlife and plant life. Petro- leum spills of this type also damage boats, fishing gear and harbor installa- tions : and the,, greatly diminish the value of the shore as a recreational resource. If not treated, such spills require long periods to biodegrade ; indeed, about 22 years is required to completelv biode rrade one kilogram of crude oil by natural processes.
Other oil spills are the result of deliberate actions such as acts of war, sabotage, and illegal discharge of cleaning fluids that are employed to clean oil tankers in preparation for carrying a petroleum product that differs from the last product carried. Petroleum products flowing through refineries and oil transport pipe systems are often spilled on land as well. Such land spills likewise require very long periods to biodegrade. Furthermore, since petro- leum products are flammable, intense fires often occur as a result of such spills. It is therefore highly advantageous to be able to contain and remove oil spuls. and to arrest the vapors so that then mav not enter and pollute the atmosphere, as soon as possible after the event.
Many methods have been used to remove oil spills from water and/or land. Such methods include physical removal of the petroleum from the water or land chemical remediation of the spilled petroleum through the use of dispersals and so-called "sinking agents." and, in some cases. intentionally burning floating petroleum slicks. Chemical remediation through the use of licuid. oil dispersant agents is the most frequently employed clean-up method because such liquids can be readily applied to large oil spills and because this method is generally more cost-effective than physical remediation methods.
Most of the more effective methods of chemically remediating oil spills involve the use of various surfactant compositions. A surfactant is a
surface-active agent whose molecuies are composed of groups of opposing polarity and solubility, i. e., surfactants usually have both an oil-soluble hydrocarbon chain and a water-soluble group. Surfactants can be anionic, cationic. or nonionic and they may be comprised ofmixrures of any of these types of surfactants. Such surfactant mixtures onen include other chemical agents, such as solvents, that enhance the dispersant capabilities of the surfactant_ However, not all surfactant compositions are effective in dispers- ing spilled oil products-and many of the more effective ones have the drawbacks of beina toxic andlor not biodegradable.
Oil spill dispersant compositions employing a wide variety of surfac- tants are found in the patent literature. For example, U. S. Patent No.
4,597,893 to Byford et al. teaches a dispersant composition for treating oil on water. The composition comprises a nonionic surfactani, an anionic sur. tac- tant_ a solvent, and water. The nonionic surfactant can be one or more polyalkoxylated (5 to 55 moles) sorbitol or sorbitan fatty acid esters contain- in 40 moles of ethylene oxide and having a hydrophilic,'lipophilic balance of of 9 to 12. The nonionic surfac : ant comprises S to 58 weight percent of the overall composition. The anionic surfactant is preferably a salt of an all ! arvl sulfonate. Tne solvent is a live-to ten-carbon primary alcohol, glycol. or glycol-ether, for example, ethylene glycol monobutyl ether. A water component also may be added as desired.
U. S. Patent No. 3,793,218 to Canevari et al. teaches dispersal of oil slicks on warer with a dispersant comprising a C, o to Go aliphatic monocarboxyllc acid or sorbitan monoesier thereof, a sorbitan monoester polyoxyalkylene adduct, and a dialkyl sulfosuccinate salt. The dispersant can be aDpiied to an oil slick with or without a solvent, such as. for example. paraffin (Isopar). The total hydrophilic/lipophilic balance of these compositions is between 9 and 11.5.
U. S. Patent No. 4,382,873 to Gatellier et al. teaches a dispersant and biodegradant for oil that has been spilled on water. The dispersani contains (1) an assimilable nitrogen compound derived from melamine, (2) a hydroxy- providing compound such as a monoalcohol or a mono alk-vl derivative of ethylene glycol, (3) an assimilable phosphorus derivative and (4) at least two of the following surface-active agents : sorbitan monolaurate, sorbitan trioleate, sorbitan monooleate, anhvdrosorbitol monooleate, an ethoxylated primary alcohol (C12-C13), or PEG (00400) mono-or di-oleate.
U.S. Patent No. 3,959,135 to Canevari teaches an oil collection agent that surrounds and collects oil that has been spilled on water. The agent is a mixture of a C, o to C, o saturated or unsaturated fattv acid or the sorbitan monoester thereof (e. _.. SPAN), and a nonpolar solvent such as isoparafun.
U. S. Patent No. 4. 146, 470 to Mohan et al. discloses a combination of microorganisms and surfactants to disperse and digest oil slicks. The microorganism is preferably Micrococcus cerificans. The surfactant mixture contains 15% to 75% by weight of (1) sorbitan monoolate (SPAN 80) and polyoxyethylene sorbitan monooleate (TWEEN 80), or (9) an aLE l aivcoside, or a mixture of (1) and (2). These surfactants may or may not be diluted in a paraffin solvent (Isopar). the HLB of the resulting composition is between 6. 9 and 9. 5.
There is. however, still a need for improved oil dispersant compositions. This need follows follows from the fact that many prior art dispersants (1) are not always effective in dispersing highly viscous orude petroleum spills. (') emplov other componeats (in addition to nonionic surfactants), e. g., anionic surfactants, solvents, and dialkyl sulfosuccinate salts, that are not readily biodegradable, or contain compounds (e. g.. certain anionic sur-actants) that are themselves extremely toxic to the environment, and (3) cannot sustain a hydrophilic/lipophilic balance at a level that serves to
increase their solubility with water. others have unacceptably short shelf lives and, hence, must be mixed in the field. and few, if any, are also capable of serving as a fire-fighting agent as well as an oil dispersant.
Solution to the Problem.
Several of the above-noted patents show that ethoxvlated sorbitol oleates have been used in various dispersants used to treat oil spills ; however, many ethoxylated sorbitol oleate-containing dispersants also have proven to be rather unstable and, hence, not well suited for long-term storage and are therefore of rather limited practical utility. Consequently, there have been many attempts to increase the stability of ethoxylaied sorbitol oleate- containing oil emulsifying agents by adding other surfactant ingredients such as. for example, primary alcohols to them. However, primary alcohols alone have proved to be rather poor stabilizers for oil dispersanis of this kind.
Applicant has. however, discovered that other types of surfactants having the hereinafter-described attributes can be added to ce : tain ethoxy- lated sorbitol oleate-containing oil-emulsifying agents to form water-miscible compositions that are very effective at emulsifying spilled petroleum and/or petroleum products and are particularly characterized by their Ions shelf lives and by the fact that they employ only nonionic surfactants that are, in turn, characterized by their relatively low toxicity to the environment and by their relativly fast biodegradability. The emulsifying compositions of the present invention also are capable of remediating oil spills on land as well as on water.
Applicant's emulsifying compositions have other utilities as well. For example, they can be used as fire-fighting agents, and especially against class B (hydrocarbon) fires in addition to class A (natural fuels), class C (electrical), and class D (metals) fires. Moreover, the herein-described oil dispersant compositions can be used as cleaning agents in those situations
where the surface to be cleaned has a high hvdrocarbon concentration, e. g., airport runwavs and aprons. as well as various container walls, for example, those of mi ! cars, tanker trucks, sea-going tankers, storage tanks, and auto- mobile fuel tanks. In still other applications. these compositions can be used to maintain and clean oil-contaminated machine tool parts and to maintain the track beds, switches, etc., of railway systems. Applicant's compositions may even be used to accelerate the rate of biodegradaiion in sewage systems. In addition. tests on live animals have shown that applicant's compositions are also exceptionally effective in the safe cleaning of oil-contaminated wildlife, such as birds, without any observable side effects. Further, applicant's compositions have been tested and found acceptable for use as cleaning agents in meat packing and poultry processing plants. These compo- sitior. have also been shown to suppress the methane produced from land fills.
SUMMARY OF THE INVENTION The present invention provides improved compositions and methods that are particularly effective for emulsifying and/or dispersing a petroleum product that has been spilled upon a portion of the earth's surface, e. g.. upon a bodv of salt water, a body of fresh water, or a portion of land. The petroleum products that can be emulsified and dispersed by applicant's comoositions can be crude petroleum, or products such as fuel oil. gasoline, jet fuel and the like. Regardless of the exact nature of the petroleum product spill, applicant's compositions should be comprised of a nonionic. primary surfactant composition, a nonionic secondary surfactant. d varying amounts of water depending upon the use to which these emulsifying and/or dispersing compositions will be applied.
Applicant's primary surfactant ingredient is an ethoxylated sorbitol oleate and more preferably is a composition comprised of a mixture of ethoxylated sorbitol oleates. That is to say that such ethoxylated sorbitol oleate mixtures will have a first ethoxvlated sorbitol oleate and at least one other ethoxyiated sorbitol oleaie. In one particularly preferred mixture, the first ethoxylaied sorbiiol oleaie is ethoxylated sorbitol septaoleate and the second eihoxyiaied sorbitol oleate is an ethoxvlated sorbitol oleate selected from the group consisting of ethoxylated sorbitol trioleate and ethoxylated sorbitol hexaoteaie. Most preferably, the nonionic, primary surfactant will comprise n'om about 45 to about 90 weight percent of the overall, end product, composition-as it is manufactured-but before it is diluted with water in the field-if indeed the end product composition is diluted in the field.
The secondary surfactant ingredient of the herein-described compositions for dispersing spilled petroleum products is most preferably a nonionic surfactant, or mixture of nonionic surfactams-and especially those nonionic surfactants having a hydrophilic/lipophilic balance (HLB) of about 10 to about 17. Most preferably, the scondary surfactants of the herein- described compositions will be selected from the group consisting of linear ethoxylated secondary alcohols, polyoxyethylene aryl ether, and ethoxylated sorbitan monolaurate. If thev are so employed. such linear ethoxylated secondary alcohols prferably will contain from about 7 moles to about 11 moles of ethyiene cx : de and have an HLB of about 10 tO about I If so employed. a polyoxyethylene aryl ether ingredien will most preferably have an HLB greater than 15.5. An ethoxylated sorbitan monolaurate ingredient will. preferably, contain from about 15 moles to about 26 moles of ethylene oxide and have an HLB of about 15 to about !". Applicant's compositions preferably will contain from about 20 to about 36 weight percent (as such
compositions are produced but before they are further diluted, if they are in fact further diluted, prior to use in the field) of such a nonionic, secondary surfactant (or mixture of such surfactants). The secondary surfactant also should be capable of stabilizing and solubilizing the primary surfactant to an n extent such that the resulting manufactured composition for emulsifying a petroleum product has an HLB from about 12. 0 to about 13. 5.
The water component of applicant's manufactured compositions may be inherentlv added to applicant's compositions as part of the manufacturing process by virtue of the fact that water may be a component of applicant's oleate ingredient (s) (e. g., about 25 to 35% thereof) and/or by virtue of the fact that water is added as a distinct ingredient in the manufacturing process.
Preferably, the water in the oleate ingredients and/or secondary surfactant insredienl (s) and/or the water added-as a distinct ingredient in a separate step <BR> <BR> <BR> <BR> in the manufacturing process will be in quantities such that the resulting emulsifying compositions, as they are manufactured, will comprise from about 0. 05 to about 30 weight percent water. The water component of the manufactured compositions of this patent disclosure (i. .. before anv addition of water to such manufactured compositions is carried out in the field) will preferably be less than about 30 weight percent of the manufactured product, and even more preferably will constitute less than 20 weight percent of such manufactured products. A separate water component used in the manufacturing process (if any is in fact used) is preferably deionized water, but fresh water or even salt water may be employed for this purpose.
Certain optional comoonents also may be added to the oil-emuisifving and/or dispersing compsoitions of this patent disclosure. These optional components preferably include an emulsion-stabilizing agent and/or a polyethylene glycol composition (and especially a polyethylene glycol having a molecular weight from about 200 to about-00'). Such optional ingredieni-
containing oil-emulsifying compositions, as manufactured, but before they undergo any dilution in the field, preferably will contain from about 1. 0 weight percent to about 4. 0 weight percent of such an emulsion-stabilizing agent, and from about 1. 0 weight percent to about 2. 0 weight percent of such a polyethylene slycol ingredient. When any, or all, of these optional ingredients are employed, it is highly preferred that resulting compositions for emulsifying spilled petroleum, nonetheless, have the 12. 0 to 13. 5 HLB value sought in those compositions compositions that not contain any optional ingredients. It also should be noted that. regardless of whether or not these optional ingredients are employed, the end product compositions for emulsifying spilled petroleum products are also particularlv characterized by their ready biodegradability, low levels of toxicity to the environment, wide range of thermal stability, ease of use (owing to the fact that thev can be premixed long before use without undergoing intervening phase separation) and. if need be. their ability to fight fires as well as disperse oil.
To further enhance the rate ofbiodegradation of the emulsifying com- positions of this patent disclosure in situations where the spill site is deficient in nitrogen, phosphorus and oxygen,small amounts of inorganic, commer- cially available fertilizers, such as mixtures of urea formaldehyde and potas- sium orthophosphates, also mav be added to applicant's compositions as additional optional ingredients. These optional fertilizer ingredients are preferably dissolved in water and added to applicant's manufactured products (again, before such products are diluted in the field) in concentrations such that no one of them forms more than about 0. =°0 of the total weiaht of the pre-field-diluted emulsifying compositions of this patent disclosure. If it is also desired to lower the freezing point or these emulsifying compositions. a also solvent such as. for example, diethylene glycol monobutyl ether also may be added as yet another optional ingredient. This ingredient, if used at
all. will be added in concentrations such that the ethylene glycol monobutvl ether constitutes from about 1. 0 to about 10. 0 weight percent of the manu- factured, end product composition.
In some of the most preferred compositions of this patent disclosure, prior to any held dilution, the ethoxylated sorbitol oleate ingredient will be a mixture of ethoxylated sorbitol oleates comprising (1) about 45 to about 50 weight percent of a first ethoxylated sorbitol oleate such as ethoxylated sorbitol sesuoleate and wherein said ethoxvlated sorbitol oleate contains from about 35 moles to about 45 moles of ethylene oxide; and (2) from about 9 to about 10 weight percent of a second ethoxylated sorbitol oleate, and especially those selected from the group of oleaies consisting of ethoxylated sorbitol trioleate and ethoxylated sorbitol hexaoleate. Ethoxylated sorbitol trioleate and ethoxylated sorbitol hexaoleate ingredients containing about 40 moles to about 50 moles of ethylene oxide are particularly effective as second. or co-surfactant, ethoxylated sorbitol oleates. The remainder of these most preferred compositions wdll be comprised of from about 20 to about 36 weight percent of the secondary surfactant and from about 0. 05 to about 30. 0 weight percent water.
The present invention also involves the use of certain hereinafter more fully described methods of contacting spilled petroleum with applicant's emulsifying compositions. To these ends. applicant's compositions may be added to a body of oil-polluted water, or land. in widely varying "loading" amounts and/or composition concentrations depending on the end result desired. the mpe of oil that has been spilled and/or the existing ield conditions. (It also should be noted thai-for the purpose of this patent disclosure, the terms "loading." "dosage," etc., should be regarded as being synonymous.) Be that as it may. a"10% solution"of : he herein-disclosed compositions may be thought of as a mixture that contains 10% by volume of
the various surfactant ingredients (and optional ingredients, if any are used) that constitute the manufactured product and 90% by volume of locallv added water. Such a 10% solution may, however, be even further diluted under certain circumstances. For example, some of the most preferred surfactant concentrations of applicant's compositions will be actually used in concentrations as low as about 3 volume percent of the overall manufactured composition (for example, such relatively low concentrations are effective when applied. with high shear, to spills of lighter petroleum products, such as jet fuel. gasoline and the like). On the other hand. solution concentrations of about 20 volume percent of the manufactured composition and 80 volume percent local water are particularly effective in dispersing somewhat heavier petroleum products (such as''light fuel oils") and lubricating oils, especially when onlv low shear can be applied-In general, spills of oils heavier than No.
It lubricating oils. but lighter than No. 6 fuel oil will call for use of oil- emulsirying manufactured compositions of this patent disclosure diluted to an erect such thai a locally provided water component will comprise from about SO to about 94 volume percent of the resulting mixture. Those compositions of this patent disclosure used to treat oil spills on land also will preferably be diluted to an extent that they comprise from about 80 to about 94 volume percent whaler, and those compositions of this patent disclosure that are applied in the context of an oil spill and fire also will most preferably comprise about 94 volume percent water and about 6 volume percent of applicant's compositions.
In general, spills of petroleum products less viscous than. say, No. 6 fuel oil and "bunker C" can be cleaned up using the manufactured compositions of this patent disclosure that have been diluted with water in the field. Such field dilution of the manufactured forms of me herein-described compositions is generally prescribed when the spilled oil is "lighter than" No.
6 fuel oil. For example. spills of petroleum products lighter than No. 6 fuel oil may be treated with applicant's compositions thai have been diluted with water m the field to such an extent that the resulting manufactured composition/local water mixture that is applied to the spill will, most preferably, be comprised of from about 10 to about 90 volume percent of the locally provided water (that is to say, another 10 to 90 volume percent of local water will be added, regardless of the fact that a given manufactured composition may itself already be comprised of from about 0. 05 to about 30 weight percent water).
Indeed. in the case of spills of very light petroleum products such as gasoline, jet fuel and the like, manufactured compositions/local water mixtures comprising up to 97 volume percent of local water (and hence, 3 volume percent of manufactured composition) may be employed, especially if local agitation (e.g., provided by a ship's wake) also is available.
When the spilled petroleum product is a heavier petroleum product (e.g., crude petroleum and, generally spenaking, a fuel oil as heavy as No. 6 fuel oil). a particularly preferred method of application is to apply a manufactured composition having no more than about 30 weight percent water (and more preferably a manufactured composition having no more than about 10 weight percent water) to the spilled oil. In other words, the manufactured composition is applied without any addition of water in the field just prior to use. Water may. however, be added to the resulting manufactured composition/spilled oil system after the manufactured composition is depioyed upon the spilled oil.
Applicant has also found that the herein-described manufactured compositions (that is, those compositions existing prior to any field dilution with locally available water) can produce total emulfification with about one (1) part of undiluted composition per about five (5) parts of a spill of No. 6
oil or bunker C oil Most heavy crude oils can be emulsified bv one (1) part of undiluted composition to ten (10) pans of oil. In all cases, the application of the compositions of this patent disclosure and the resulting emulsions vastlv reduce the tendency of oil slicks on water to adhere to rock surfaces.
In many cases an emulsifying effect may be all that is required and/or desired to disperse a given oil spill, but in most cases biodegradation of the emulsified oil/dispersant combination is the more desired end result. In any case. the compositions of the present invention are highly biodegradable in the context of such oil spill emulsifications. Applicant's tests have shown that most emulsified oil/dispersant systems produced by the herein-described compositions will biodegrade by about 80% within four (4) days of application of the herein-described compositions to an oil spill in water.
Indeed. applicant has found that even wilhin the first three (3) hours after application of applicant's compositions, about 10% biodegradation of the oil/dispe : sant svstem is ootained. In other tests. applicant found that up to about 97% biodegradation was obtained within 28 days after application. In net another laboratory test, total elimination of the oil/dispersant combination was observed within S days after application of some of applicant's compositions to certain"light"petroleum products.
DETAJLED DESCRIPTION OF THE INVENTION 1. Particularly Preferred Formulations Re : Certain ADplications.
As previously stared, applicant has found thai particularly good oil emuisificaiion results are obtained when the secondary surfactant of the present invention stabilises and solubilizes the primary surfactant composi- tion to a degree such that the resulting, manufactured end product composi-
tior. s (before anv fie ! d dilution of such manufactured compositions takes place) have a hydrophilic/lipophilic balance (HLB) between about 12. 0 and about 13.5. Those skilled in this art will appreciate thai the tetm "HLB" as used herein is a wen-known measure of the relative hydrophilicity or lipo- philicirv of a surfactant composition. Generally speakins, HLB values are obtained bv dividing the molecular weight of the hydrophilic component of a compound bv the molecular weight of the compound and multiplying the resulting number by selected adjuster values known to those skilled in this art. values range on a scale from 1 to more than'0. with 1 indicating the least hydrophilic and 20 and above indicating the most hydrophilic.
Applicant has found that the stability of the dispersant/spilled oil emulsions produced by the compositions of this patent disclosure can be further increased when small amounts of an emulsion-stabilizing agent are included in applicant's compositions. These emulsion-stabilizing agents are often used to provide steric stabilization of dispersed particles (for example, literature published by Imperial Chemical Industries PLC (ICI) suggests use of their Hypermer A409# and Hypermer A394# compositions for this pur- pose). Applicant has. however, found that the inclusion of such emulsion- stabilizing agents in the herein-described compositions for dispersing spilled petroleum products greatly increases the stability of the resulting petro- leum/composition emulsion. This is an important finding because the in- creased longevity of the petroleurn/composition emulsion enables the emul- sion to be more completely biodegraded. Some of me better descriptions of such emulsion-stabilizing agents are found in the technical literature pub- lished by their manufacturers, and therefore, applicant hereby incorporates by reference the following publication describing the properties of ICI's Hyper- mer@ compositions: "Hypermer@ Polymeric Surfactants and Dispersants for Industrial Applications". ICI Americas Inc., 1994. Regardless of the identirv
of their supplier, however. such emulsion-stabilizing agents may constitute from about 1. 0 to about 4. O weight percent of the overall manufactured compositions of this patent disclosure.
2 Particulariv Preferred Methods of Formulating and Deploying Compositions To prepare the emulsifying compositions of the present invention, the primary surfaciant composition is preferably made bv first combining, the first and the second ethoxylaied sorbitol oleates under light, nonaerating agitation, If desired, the emulsion-stabilizing agent and/or the polyethylene glycol are combined under moderately high shear conditions and then blended with the primary surfactant composition. In some of the more preferred embodiments of this invention. the secondary surfactant is added to the primary surfactant composition by blending it under nonaerating shear conditions. Finally, the water component, if desired, is preferably added by blending under low shear conditions.. Again, it should be understood that additional water can be incorporated into the manufactured compositions of this patent disclosure at a later time, e.g., just prior to use. so that smaller volumes of the manufactured compositions of this patent disclosure may be transported to a spill site.
The emulsifying compositions of the present invention may be ap- plied to petroleum spills on water or on land by conventional methods known to those In the oil spill remediation arts, e.g., using various tank and spray nozzle devices. For example, applicant's emulsifying compositions may be sprayed directly on petroleum spills on water or on land with a small diameter hose equipped with a spray nozzle to supply a uniform spray. It also should be noted thai it is not necessary to apply the compositions using a high-pressure hose. For large petroleum spills, applicant's compositions may be applied by using a helicopter equipped with tanks having a dump spout that can be operated from within the helicopter or such helicopters may be
provided with tanks and a pipe manifold systems that are affixed to a plural- itv of spray nozzles.
For petroleum spills on land. dispension of the emulsifying composi- tions of this patent disclosure may be followed by physical agitation of the soil and then ftushins with water. Alternatively, applicant's compositions also may be dispensed under pressure, for example, by a conventional fire extinguisher, whereby the pressure supplied by such a device mixes the emulsifying composition with the petroleum and simultaneously flushes it awav.
This invention is further illustrated by reference to the following tests conducted upon various formulations of the compositions of this patent disclosure with respect to their dispersion abilities, biodegradation. and <BR> <BR> <BR> <BR> toxiciiy.<BR> <BR> <BR> <BR> <BR> <BR> <BR> <BR> <BR> <P>3. Test Formulanons.
Three emulsifying compositions were prepared having the following three formulations A,B, and C : Emulsifier Formulation A 45 weight percent - Ethoxylated sorbitol septableate, containing 40 moles ofethylene oxide.
9 weiught percent-Ethoxylated sorbitol trioleate, containing 40 to 50 moles ofeihylene oxide.
>6 weight percent - linear ethoxylated secondary alcohol, containing 7 to I moles ofethylene oxide ajnd having an HLB of between 10 and I-, preferably 13.
10 weight percent-water.
Emulsifier Formulation B >0 0 weight percent - ethoxylated sorbitol septaoleate, containing 40 moles of ethylene oxide,
10 weight percent-ethoxylaied sorbitol hexaoleate, containing 50 moles ofethylene oxide.
20 weight percent - polyoxyethylene aryl ether, having an HLB of <BR> <BR> <BR> <BR> <BR> greater than 15. 5.<BR> <BR> <BR> <BR> <BR> <BR> <BR> <BR> <P> 20 weight percent-water.
Emulsifier Formulation C 45 weight percent-eihoxyiated sorbitol septaoleaie. containing 40 moles of ethylene oxide.
9 weight percent - ethoxylated sorbitol trioleate.
26 weight percent - ethoxylated sorbitan monolaurate.
20 weight percent-water. a) Dispersion Emulsifier formulation A was tested using a conventional low-energy swirling flask dispersant effectiveness test. This test is more fully described in 40 CFR Section 300 and said regulation is incorporated into this patent disclosure. The specific oil types used in applicant's test were two standard reference oils, that is. Prudhoe Bay Crude and South Louisiana Crude (a lighter oil than the Prudhoe Bay Crude). The test was performed in'artificial sea water" (made from Instant Ocean) made to a salinity of 35 parts per thousand. One part (by weight) of emulsifying formulation A was used to 10 pans (by weight) of oil. The rest was done with three or four replicate sam- ples. Results were measured as the LU-VIS spectrophomeiric absorbance at ,-10 nm. 370 nm. or 400 nm. The results of these tests are expressed below as the percentage of the oil remaining dispersed for 10 minutes after all agitation had ceased. Those skilled in this art will appreciate that in the oil remediation ars, a dispersion of 45% of the oil in such tests is regarded as being an acceptable test result. The results of applicant's tests are given in Table I and Table II.
TABLE I % Dispersibility of Prudhoe Bay Crude Replicate I Replicate Replicate 3 Absorbance 45 54 47 at 340 nm A, Absorbance at 370 Absorbance at 400 nm SD SUD Ove. ail 4 average = SD TABLE II oiZO Dispersibility of South Louisiana Crude Replicate 1 Replicate 2 Replicate 3 Replicate 4 Absorbance 65 68 67 65 at 340 nm Absorbance 64 67 67 64 at 370 nm Absorbance 63 66 65 63 at 40 nm Average = 64 = 0.7 67 = 1.0 66 = 0.9 64 = 0.7 SD Overaill 65=1.3
averase = SD Tables I and II clearly show that emulsifying formulation A disperses 48°'0 of the Prudhoe Bay Crude and 6>% of the South Louisiana Crude.
Applicant also conducted emulsirying and dispersing tests with emul- sifting formulation A using concentrations as low as about 3% solutions with respect to "lighter" oil products such as No. 2 diesel oil, under moderately hi'th shear conditions. However, applicant also found that if less agitation is available. somewhat higher concentrations, e.g., 15% solutions, were often required 10 emulsify and disperse a like amount of the No. 2 diesel oil. Bv wav of contrast, in order to emulsify and disperse No. 6 fuel oil, a 100% solution of formulation A was applied at a ratio of one (1) part of composi- tion to 10 pans of oil under moderate agitation to produce the desired emulsi- fication effects. b) Biodegradation The relatively quick and extensive biodegradation property of the oil- emulsifvins compositions of this patent disclosure is one of their more important properties. It was tested using various tests known to the art includins the E. M. P. A. test (the is a Swiss government organiza- tion charged with certifying oil-dispersant and emulsifying compositions). To this end. a standard test (EMPA SOP 720) was performed on emulsifying formulation A determine the rate of biodegradation of this formulation in combination with an oil sludge over a period of 28 days. The amount of degradatiuon was determined by measuring the percentage of the initial total oxygen concentration. In such tests-applicant found that about 73% of a combina of emulsifying formulation A oil sludge (at a concentration of 118 mg of formulation A per liter of oil sludge) was biodegraded by day 3 of
the experiment and about 81% was biodegraded by day 21. The further results of this test are shown in Table III.
TABLE ni Day% Initial Total Oxygen Concentra- tion (TOC) 0.1 10 0 373 14 79 ='1 S1 ='S 81
Consequently, these test indicate that the values for the biodegradaiion of emulsifying formulation A in combination with oil sludae are well within the acceptable range for certification of emulsifvmg fornulation. A by the E.M.P.A.
Applicant's own laboratory and field tests showed that more than 81% degradation of a combination of oil and emulsifying formulation A was observed within four (4) days of application. In these tests. about 10% of the biodegradation occurred within the first three (3) hours after application of formulation A. In other tests, more than 97% of the oil/emulsifying formulation A combination was biodegraded aner 2S days. Total elimination of the oil/formulation A combination in eight (8) days was observed m yet another laboratory test. The significance of these results can be better
appreciated when one considers that natural biodegradation of one (1) kilogram of crude oil may take as long as 22 years. c) Toxicitv Another advantageous artyribute of applicant's emulsifying/dispersant compositions is their low toxicity, especially toward aquatic life. In order to verify this low toxicity, a sample of formulation B (as desc ibed above) was tested for toxicitv against two aquatic organisms, brine shrimp (Artemia sp.) and a species of fish (Fundulus hereroclitus). The test procedure involved exposing the organismes to increasing concentrations emulsifying formulation B alone and to a combination of equal amounts of emulsifying formulation B and diesel oil and determining the LC50 (the concentration of formulation B alone or formulation B/oil combination that kills 50% of the organisms) aner 48 hours of exposure for the shrimp and 96 hours of exposure for the fish. The LC<o values for emulsifying formulation B alone were compared with LCso values for other dispersants of comparable efficiency as listed in the National Contingency Plan denned in 40 CFR Section 300. The results are shown in Table IV.
TABLE IV Dispersant LC50 (ppm after 96 hours) for Fundulus hours) for Artemia . Houris,) ying 4900 2500 tormulation B D-9 1 6--, 0 D-27 100 60 D-61 180 60 D-62 71 8 D-@@ 109 155
The data in Table IV show that. for example, only 115 ppm (parts per million) of product D-9 will kill one-half of the fish in 96 hours, whereas 4900 ppm of applicant's emulsifving formulation B is required to kill one- half of the fish in the same period. For. 4rtemia sp., the comparative dispersants kill one-half of the shrimp in 48 hours at concentrations of 8 to 630 0 ppm. Emulsinring formulation B, by contrast, had an LC50 of 2500 ppm against 4uremia sp. These tests indicate that emulsifying formulation B is less toxic than comparative dispersants by an order of magnitude.
When emulsifying formulation B was mixed with an equal amount of diesel oil and this diesel oil/emulsifier combination was tested for toxicity against organisms in the same way as described above. the LC50 for Artemia sp. was 1500 ppm, and the LC<o for Furdulus sp. was I400 ppm. Again. these toxiciry values are far lower than the LC50 values shown in Table IV for comparative dispersants without oil.
The above disclosure sers forth a number of embodiments of the pres- em invention. Those skilled in this art will however appreciate that other embodiments, not precisely set forth, also could be practiced under the teachings of the present invention and that the scope of this invention should only be limited by the scope of the following claims.