Archive for the ‘CLEANING’ Category


Monday, April 16th, 2012


As the world’s appetite for oil and gas continues to increase while access to easily accessible reserves decreases, deep-sea oil and gas wells are being positioned in ever-deeper waters. The dangers and difficulties faced in such operations were highlighted in 2010 with the Deepwater Horizon oil spill. While placing a containment dome over a leak and piping the oil to a surface storage vessel had worked on leaks in shallower water, the attempt to do the same on the Deepwater Horizon’s largest leak failed when the formation of methane hydrate crystals blocked the opening at the top of the dome. Now researchers at MIT have developed surface coatings that can inhibit the buildup of these methane hydrates and keep the gas and oil flowing.

Methane hydrate is a solid cage-like compound – or clathrate – that forms under very high pressure in which a large amount of methane is trapped within a crystal structure of water to form an ice-like solid. Although it was originally thought to only occur in the outer reaches of the solar system, it is now estimated that total amount of methane contained in hydrates in the world’s seafloor is much greater than the total known reserves of all other fossil fuels combined.

Much like the buildup of cholesterol and fatty deposits on the inner walls of arteries inside the body, the buildup of methane hydrates – which can freeze upon contact with cold water in the depths of the ocean – inside a well casing or on the inner walls of pipes that carry oil or gas from the ocean depths can restrict or even block the flow of gas or oil. It was this kind of blocking that caused the failure of the containment dome technique attempt on the Deepwater Horizon leak.

Current techniques to prevent this happening include the heating or insulation of the pipes – which is expensive – or adding methanol into the flow of gas or oil – which can harm the environment if it escapes.

An MIT team led by associate professor of mechanical engineering Kripa Varanasi had been looking for a solution to this problem even before the Deepwater Horizon spill and now say they have found it. Having already studied the use of superhydrophobic surfaces to prevent the buildup of ordinary ice on things such as aircraft wings, the team decided to examine whether similar surfaces could be used to keep pipe walls clear of methane hydrates.

Using a simple “hydrate-phobic” coating, Varanasi and his colleagues were able to reduce the adhesion of hydrates in a pipe to one-quarter the amount compared to untreated surfaces.

“The oil and gas industries currently spend at least $200 million a year just on chemicals” to prevent methane hydrate buildups, Varanasi says. However, the total figure for prevention and lost production due to hydrates would be much, much higher. Using passive coatings on the insides of pipes would be much cheaper than current prevention techniques and allow the use of containment domes to capture flows from leaks in much deeper waters than is currently possible.

Additionally, the team says the test system they devised provides a simple and inexpensive way to search for even more effective inhibitors. They say their findings are also applicable to other adhesive solids, such as solder adhering to a circuit board, or calcite deposits inside plumbing lines. The testing methods developed by the researchers could also be used to evaluate coatings for a variety of commercial and industrial processes.

The team’s findings are detailed in a paper published in the journal Physical Chemistry Chemical Physics.

Source: MIT

Published by Henry Sapiecha


Sunday, March 27th, 2011

Liquid salt could help clean up tar sands

By Ben Coxworth

15:06 March 23, 2011

A tar sand sample treated with the ionic liquid process(Photo: Penn State University)

A tar sand sample treated with the ionic liquid process
(Photo: Penn State University)

The United States imports approximately one million barrels of oil per day from Canada, which is about twice the amount that it gets from Saudi Arabia. A large percentage of that oil comes from tar sand deposits, in which bitumen (a tar-like form of crude oil) is found combined with sand. The tar sands – also known as oil sands – are hugely controversial, as many people state that the process used for extracting the oil from the sand is too ecologically-unfriendly. A new technique being pioneered at Penn State University, however, could drastically reduce the environmental impact of that process.

The current method of separating sand and bitumen involves adding warm water to the two, then agitating the mixture. Unfortunately, it requires a lot of water, which is diverted from nearby rivers. Once the separation process is complete, the now-polluted water is pumped into open air tailings ponds. From there, it can potentially leach its way back into the water table. There’s also another risk – despite the presence of bird-scaring devices, in 2008 approximately 1,600 ducks died when they landed in one of the ponds.

Instead of warm water, the Penn State method utilizes room temperature ionic liquids (ILs), which consist of salt in a liquid state – a solvent such as toluene may also be added. When the ILs are introduced to a sand/bitumen mixture and stirred, the resulting combination settles into three distinct layers: a bottom layer of oil-free sand, a middle layer of ILs, and a top layer of bitumen. The bitumen can then be removed and refined, the ILs can be reused, and residual ILs in the sand can be removed using a relatively small amount of water (which can also be reused), after which the sand can be returned to the environment.

Not only is much less water used, but because nothing needs to be heated, there are also substantial energy savings.

The researchers state that the ionic liquids could also be used to clean up beaches devastated by oil spills. Sand could be cleaned and redeposited on the spot, supposedly containing even less hydrocarbons than it did before the spill ever occurred.

We’ll be watching this one with interest …

Sourced & published by Henry Sapiecha