GULF OIL SPILL BP's Oil Dispersants - itopf

Dispersants have two main components: a surfactant and a solvent. Surfactants molecules are made up of two parts: an oleophilic part (with an attraction to oil) and a hydrophilic part (with an attraction to water). When dispersants are sprayed onto an oil slick, the solvent will transport and distribute the surfactants through the oil slick to the oil/water interface where they arrange themselves so that the oleophilic part of the molecule is in the oil and the hydrophilic part is in the water. This creates a reduction in the surface tension at the oil/water interface and small oil droplets will break away from the oil slick with the help of wave energy. These droplets will be of varying sizes and although the larger ones may rise back to the surface some will remain in suspension and will drift apart and become degraded by naturally occurring bacteria. If dispersion is successful, a characteristic brown plume will spread slowly down from the water surface a few minutes after treatment.

Dispersants have little effect on very viscous, floating oils, as they tend to run off the oil into the water before the solvent can penetrate. As a general rule, dispersants are capable of dispersing most liquid oils and emulsions with viscosities of less than 2000 centistokes, equivalent to a medium fuel oil at 10-20ºC. They are unsuitable for dealing with viscous emulsions (mousse) or oils which have a pour point near to or above that of the ambient temperature. Even those oils which can be dispersed initially become resistant after a period of time as the viscosity increases as a result of evaporation and emulsification. For a particular oil, the time available before dispersant stops being effective depends upon such factors as sea state and temperature but is unlikely to be longer than a day or two. Dispersants can, however, be more effective with viscous oils on shorelines because the contact time may be prolonged allowing better penetration of the dispersant into the oil.

• Type 1 dispersants are based on hydrocarbon solvents with between 15% to 25% surfactant. They are sprayed neat onto the oil as pre-dilution with sea water renders them ineffective. Typical dose rates are between 1:1 and 1:3 (dispersant:oil).
• Type 2 dispersants are dilutable concentrate dispersants which are alcohol or glycol (i.e. oxygenated) solvent based with a higher surfactant concentration. Dilution is normally 1:10 with sea water.
• Type 3 dispersants are also concentrate dispersants with a similar formulation to type 2 products. However, they are designed to be used neat and typical dose rates are between 1:5 and 1:30 (neat dispersant:oil).
Type 1 and 2 dispersants require thorough mixing with the oil after application to produce satisfactory dispersion. With type 3 products, the natural movement of the sea is usually sufficient to achieve this. The lower application rates required with concentrates mean that types 2 and 3 have largely superseded type 1 dispersants for application at sea.


http://www.itopf.com/spill-response/clean-up-and-response/dispersants/
- itopf

Category:

Science & Technology

Tags:

• BP
• OIL
• SPILL
• GULF
• OF
• MEXICO
• DISPERSANTS

[rickyvaughn2]

my understanding is that the dispersant job is not to make the oil sink to the bottom, but, to make the ppm go very high to the point of almost being undetectable. this is why a hurricane would actually help this problem, it would throw this stuff all over the place helping "disperse" it even more.

[GREENPOWERSCIENCE]

@rickyvaughn2 That is the goal but dispersants only really work on a thin oil sheen and the crude oil only become undetectable if microbes and other natural methods of decomposition completes the process. Thicker slicks clump up and sink or the dispersant rolls off of the top.

[MillyVanillification]

dispersants are primary used to cover up the real damage and to spare the cleanup from the assole who caused it. Its far easier to collect crude oil when no dispersant is used. By the way, which idiot thinks that its better to throw even more toxic chemicals at the oil than whats already there? Must be some share-holder-value.

[rainerfilm]

@rickyvaughn2 Oil does not evaporate. Take some diesel (which is oil based) and put it outside in the sun, it will not evaporate. all of the oil can not be cleaned up, but is is best to remove as much as possible before allowing nature to take over. I agree that the last bit will be done by Nature, but not now, we still have many tones of oil to remove before that will be acceptable.

If people don't see the damage nothing will be done to it.

[virgoptrex]

BP = Bastard Pathetics!

[rtpur85]

looks like someone played a game of stink finger and lost.

[wisetrucker]

Union carbide and india and the deaths of thousands, how come you never ever mention that, could it be because it was not in america. Also the british government refused to sell tank transporters to libya, but guess who did but called it agricultural machinary transport, yes your right america, the dollar was calling and it was louder then the ethics of the case. You americans are so two faced you never know which way you are facing sometimes, but it always points towards an arsehole, yourselve

[Aesus1]

You can't skim dispersed oil :(

[taliewacker2007]

so its baking soda, that turn oil and water into soup, degreaser is not good either

[collintheapplegeek]

BP just wAnts to make the oil sink so that it can't be seen by news cameras

[MistressLuxuria]

How would the oil spill and the dispersant act upon the possibility of water desalination in the affected areas and could this be a global problem if the spill is not stopped within a reasonable amount of time? It's been months and the big brains who were able to invent HAARP and space shuttles can't frikkin put a sock in a hole? I don't know I think these things happening are all very suspicious...

[dondude69]

Could this possibly cause an increase in petroleum consuming bacteria with potentially detrimental side effects?