Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
1999-11-08
2002-04-09
Metzmaier, Daniel S. (Department: 1712)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S417000, C510S422000, C510S424000, C510S427000, C510S432000, C510S492000, C510S495000, C510S505000, C510S506000, C516S058000
Reexamination Certificate
active
06369016
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to a heavy oil remover formulation. More particularly, the invention is directed to a composition useful for removing heavy oil and oily sludges from process equipment such as storage tanks, transfer piping, and pumping facilities.
BACKGROUND OF THE INVENTION
Compositions for heavy oil degreasing, capable of removing and displacing heavy oils from oil sludges left in process equipment, e.g., oil storage tanks, are known. The conventional heavy oil degreaser compositions contain so-called “alkaline builders.” Moreover, many heavy oil remover compositions include halogens which are undesirable for steel process equipment degreasers, because the halogens may contribute to stress cracking of the metal. Many heavy oil degreasers only work at full strength, and are ineffective when diluted by residual liquids contained within the process equipment being cleaned. Some heavy oil degreasers are ineffective at ambient temperatures and must be heated along with the process equipment in order to remover the heavy oil sludge. Conventional heavy oil removers generally are incapable of absorbing and/or neutralizing the toxic gases and vapors which have accumulated within fouled process equipment.
U.S. Pat. No. 5,085,710 to Goss discloses a composition for removing oil sludges utilizing an alkylphenol adduct and a castor oil etholylate. U.S. Pat. No. 5,389,156 to Mehta et al discloses a heavy oil degreaser including a terpene and a second nonionic co-surfactant from the family of ethylene oxide/propylene oxide polyol adducts. These disclosed formulations suffer from a number of the undesirable characteristics listed above.
It would be desirable to prepare a heavy oil remover composition that is free from alkaline builders and halogens, effective even at significant levels of dilution and at ambient temperatures, capable of absorbing toxic gases and vapors such as hydrogen sulfide and benzene, and nontoxic.
SUMMARY OF THE INVENTION
Accordant with the present invention, there surprisingly has been discovered a heavy oil remover, comprising: from about 3 to about 96 weight percent hydrocarbon solvent; from about 1 to about 94 weight percent dipropylene glycol mono n-butyl ether; from about 1 to about 95 weight percent of a volatility stabilizer; from about 2 to about 95 weight percent salt of an alkyl aromatic sulfonic acid; from about 0.1 to about 75 weight percent branched alcohol ethoxylate; from about 0.1 to about 75 weight percent ethoxylated alkyl mercaptan; and up to about 95 weight percent water.
The heavy oil remover according to the present invention is particularly useful for removing residual oil sludges from fouled process equipment such as, for example, oil storage tanks.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The heavy oil remover composition according to the present invention comprises a hydrocarbon solvent, dipropylene glycol mono n-butyl ether, a volatility stabilizer, a salt of an alkyl aromatic sulfonic acid, a branched alcohol ethoxylate, an ethoxylated alkyl mercaptan, and water.
The design of a high quality heavy oil remover requires attention to the chemical characteristics related to the performance enhancements required to achieve removal of heavy oils at ambient temperatures. Specifically, the most important chemical characteristics are solvency and detergency (or ability to emulsify). These factors affect the heavy oil remover s ability to clean and degrease metal surfaces, its impact on corrosion of the metal surfaces, and its ability to be safely handled.
The heavy oil remover according to the present invention exhibits the desired characteristics of solvency and detergency. Moreover, halogens are absent from the formulation, thus reducing the potential for stress cracking of the metal process equipment. The inventive formulation is effective at room temperatures, even when substantially diluted with water or residual process fluids. Finally, the composition can absorb toxic vapors such as hydrogen sulfide and benzene, yet is itself non-toxic.
In order to assure continued performance of the heavy oil remover under actual use conditions, the present formulation contains a volatility stabilizer. This enhances the formulation's aged heavy oil removing performance by slowing the evaporative losses of the other solvents, while synergistically working with the hydrocarbon solvent and dipropylene glycol mono n-butyl ether to provide improved heavy oil removing ability.
The hydrocarbon solvent according to the present invention may be a terpene or a petroleum solvent, or any mixture thereof. Suitable terpenes include diterpenes, triterpenes, and tetraterpenes which are generally head-to-tail condensation products of modified or unmodified isoprene molecules. The terpenes may be mono-, bi-, tri-, or tetracyclic compounds having varying degrees of unsaturation. Also contemplated as useful in the present invention are terpene derivatives, e.g., alcohols, aldehydes, etc., sometimes referred to as terpenoids, and mixtures of terpenes.
Petroleum solvents are well-known byproducts of the petroleum refining industry, and include by way of example but not limitation, light straight run gasoline, catalytic reformate, hydrocracked gasoline, catalytically cracked gasoline, polymer gasoline, alkylate, #1 fuel oil, #2 fuel oil, kerosene, jet fuel, diesel fuel, heating oil, furnace oil, naphtha, middle distillate, white oil, lubricating oil, gas oil, cyclopentane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, 1,2-dimethylcyclohexane, decahydronaphthalene, and the like, as well as mixtures and derivatives thereof. A useful hydrocarbon solvent may be obtained from the Exxon Chemical Company under the trade designation “EXXOL D-60.” Other useful hydrocarbon solvents include gasoline, diesel fuel, and gas oil. A preferred hydrocarbon solvent is d-limonene.
D-limonene is a terpene which occurs naturally in all plants. It is a monocylic unsaturated terpene which is generally a by-product of the citrus industry, derived from the distilled rind oils of oranges, grapefruits, lemons, and the like. A discussion concerning d-limonene and its derivation from numerous sources is set forth in Kesterson, J. W., “Florida Citrus Oil,” Institute of Food and Agriculture Science, University of Florida, December, 1971. D-limonene exhibits low human toxicity and is considered environmentally benign. It functions in the present inventive formulation as a portion of the solvent phase, for solubilizing the petroleum sludges, and as an absorbent for benzene contained in the oil sludges and the vapor spaces of the process equipment. Furthermore, d-limonene exhibits excellent solubility for the higher bitumen and asphaltene compounds commonly found in petroleum sludges. D-limonene is commercially available from Florida Chemical Company and from SMC Glidco Organics.
The hydrocarbon solvent may be present in the inventive formulation at a concentration from about 3 to about 96 weight percent. Preferably, the concentration is from about 5 to about 15 weight percent. Most preferably, the concentration of hydrocarbon solvent is about 10 weight percent.
Dipropylene glycol mono n-butyl ether according to the present invention acts synergistically with the hydrocarbon solvent as a second component of the solvent phase. It is a moderately polar solvent, having excellent solvency for petroleum compounds, including waxes, and for other polar compounds present in trace amounts in petroleum sludges. This solvent component is non-toxic, and exhibits a high flash point and low flammability making it safer to use than many other solvents. Finally, it contributes to the overall stability of the inventive formulation and acts as an important coupling agent between the hydrocarbon solvent and the aqueous phase of the micro emulsion produced using the instant heavy oil remover. The dipropylene glycol mono n-butyl ether may be present in the inventive formulation at a concentration from about 1 to about 94 weight percent. Preferab
Dotolo Research Ltd.
Fraser Donald R.
Metzmaier Daniel S.
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