Petroleum distillates with increased solvency
Certain fatty acid amide-based surfactants such as cocamide DEA (also known as “coco(nut) diethanolamide” or “coco(nut) DEA”) when dissolved or dispersed in a cutting oil (diesel, light cycle oil, naphtha, and such other petroleum distillates) produce a petroleum distillate having significantly enhanced solvency for heavy residuals. Such solutions or dispersions are especially useful for cleaning vessels and similar equipment in refineries by circulating the solution or dispersion in the vessel, optionally with the application of heat.
1. A method of cleaning a vessel containing one or more heavy forms of petroleum, said method comprising:
dissolving or dispersing only a fatty acid amide-based surfactant in a petroleum distillate to form a solution or dispersion thereof;
introducing the solution or dispersion into the vessel; and contacting the one or more heavy forms of petroleum with the solution or dispersion.
2. The method recited in claim 1 wherein the fatty acid amide-based surfactant is selected from the group consisting of cocamide DEA, cocamide MEA, cocamidopropyl betaine (CAPE), and cocamidopropyl hydroxysultaine (CANS).
3. The method recited in claim 1 wherein the petroleum distillate is selected from the group consisting of cutter stock, diesel oil, light cycle oil, heavy cycle oil, naphtha, kerosene, light vacuum gas oil, heavy gas oil, and mixtures thereof.
4. The method recited in claim 1 wherein the fatty acid amide-based surfactant is cocamide DEA and the petroleum distillate is diesel oil.
5. The method recited in claim 4 wherein the cocamide DEA surfactant comprises about 1 percent by volume of the solution or dispersion.
6. The method recited in claim 1 further comprising:
soaking the contents of the vessel in the solution or dispersion of the fatty acid amide-based surfactant in the petroleum distillate for a time sufficient to substantially dissolve the contents contained in the vessel.
7. The method recited claim 6 wherein the solution or dispersion of the fatty acid amide-based surfactant in the petroleum distillate is at ambient temperature.
8. The method recited claim 6 wherein the solution or dispersion of the fatty acid amide-based surfactant in the petroleum distillate is maintained at an above-ambient temperature.
9. The method recited in claim 8 wherein the above-ambient temperature is about 140° F.
10. The method recited in claim 1 further comprising:
circulating the solution or dispersion of the fatty acid amide-based surfactant in the petroleum distillate within the vessel.
11. The method recited claim 10 wherein the solution or dispersion of the fatty acid amide-based surfactant in the petroleum distillate is at ambient temperature.
12. The method recited claim 10 wherein the solution or dispersion of the fatty acid amide-based surfactant in the petroleum distillate is maintained at an above-ambient temperature.
13. The method recited in claim 12 wherein the above-ambient temperature is about 140° F.
14. The method of claim 1 , wherein the one or more heavy forms of petroleum is crude oil, asphalt, bitumen, or sludge.