Retraction of oil slicks using surfactants

Patent metadata

Field	Value
Publication number	US-9797109-B2
Application number	US-201213653942-A
Country	US
Kind code	B2
Filing date	Oct 17, 2012
Priority date	Oct 17, 2011
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A method for retracting oil on a water surface, and a method for reducing the quantity of oil on an oil control boom are described. Spreading of oil can be reversed by reducing the surface tension of the seawater, for example by using a low concentration of a water-soluble surfactant, such as a non-ionic surfactant. A controlled amount of the surfactant may be continuously discharged at the inner-wall of a spill control boom surrounding the oil spill. The spilled oil is caused to retract away from the boom toward the center of the area encircled thereby, such that the oil layer becomes sufficiently thick to be more effectively removed mechanically. The surfactant also reduces the amount of oil on the spill control boom, whereby the boom can easily be removed from a remediated oil spill and reused at a later date without further cleaning.

First claim

What is claimed is:

1. A method for retracting an oil slick, having a spreading coefficient, S, on a water surface, comprising the steps of: surrounding the oil slick with a floating oil control boom having length defining an enclosed area; dispersing at least one water-soluble surfactant having the chemical formula CH 3 (CH 2 ) n O(CH 2 CH 2 O) y H, where 8≦n≦10, and the average value for y is 8.3, in the water between the floating oil control boom and the oil slick adjacent to the wall of the floating oil control boom, to obtain a concentration consistent with maintaining the spreading coefficient at a value less than zero; and reducing the length of the floating oil control boom to reduce the enclosed area.

2. The method of claim 1 , wherein the at least one water-soluble surfactant is mixed with solid materials such that the rate of dispersion of the at least one water-soluble surfactant into the water is reduced.

3. The method of claim 1 , wherein the water comprises seawater.

4. The method of claim 1 , further comprising the step of mechanically removing oil from the oil slick.

5. A method for removing an oil slick, having a spreading coefficient, S, from a water surface, comprising the steps of: surrounding the oil slick with a floating oil control boom having a length defining an enclosed area; dispersing at least one water-soluble surfactant having the chemical formula CH 3 (CH 2 ) n O(CH 2 CH 2 O) y H, where 8≦n≦10, and the average value for y is 8.3, in the water between the floating oil control boom and the oil slick adjacent to the wall of the floating oil control boom, to obtain a concentration consistent with maintaining the spreading coefficient at a value less than zero; and mechanically removing oil from the oil slick.

6. The method of claim 5 , further comprising the step of reducing the length of the floating oil control boom to reduce the enclosed area.

7. The method of claim 5 , wherein the at least one water-soluble surfactant is mixed with solid materials such that the rate of dispersion of the at least one water-soluble surfactant into the water is reduced.

8. The method of claim 5 , wherein the water comprises seawater.

9. A method for reducing oil, having a spreading coefficient, S, on a floating oil control boom, comprising the steps of: placing the oil control boom in water; dispersing a chosen concentration of at least one water-soluble surfactant having the chemical formula CH 3 (CH 2 ) n O(CH 2 CH 2 O) y H, where 8≦n≦10, and the average value for y is 8.3, in the water in contact with the floating oil control boom; and maintaining the chosen concentration of the at least one water-soluble surfactant in contact with the floating oil control boom at a level consistent with the spreading coefficient of the oil being maintained at less than zero.

10. The method of claim 9 , wherein the at least one water-soluble surfactant is mixed with solid materials such that the rate of dispersion of the at least one water-soluble surfactant into the water is reduced.

11. The method of claim 9 , wherein the water comprises seawater.

Assignees

• Univ Wyoming

Inventors

• Takamura Koichi
• Morrow Norman R
• Loahardjo Nina
• Winoto Winoto

Classifications

• B01D17/04

  Breaking emulsions · CPC title

• C02F2103/08

  Seawater, e.g. for desalination · CPC title

• E02B15/041 Primary

  Devices for distributing materials, e.g. absorbed or magnetic particles over a surface of open water to remove the oil, with or without means for picking up the treated oil (E02B15/042 takes precedence) · CPC title

• C02F1/682 Primary

  by addition of chemical compounds for dispersing an oily layer on water · CPC title

• C02F1/40

  Devices for separating or removing fatty or oily substances or similar floating material (cleaning or keeping clear the surface of open water from oil or like materials E02B15/04; devices in sewers for separating liquid or solid substances from sewage E03F5/14, e.g. for use in drains leading to the sewer E03F5/16) · CPC title