LONDON: A NEW way to treat carbon dioxide to allow it to be used in efficient and environmentally friendly methods for extracting oil has been developed by a university research team.

The team led by the University of Bristol, western England, has used the ISIS neutron source at the UK's Science & Technology Facilities Council's facility to develop the CO2-soluble additives.

These can also be used to reduce the environmental damage caused by everyday industrial processes such as the manufacture of electronics and food processing.

Bristol University's Professor Julian Eastoe believes that getting longer life out of existing oil reserves will give more time for research into replacements into non-carbon energy sources such as solar or hydrogen. The UK's Minister for Science, David Willetts, said: "This shows what science can do for the environment."

The researchers have developed a soap-like additive for CO2 that turns it into a viable solvent for commercial-scale enhanced oil recovery to increase the amount of crude that can be extracted from oil fields.

"There is also a useful side-effect of our ability to use CO2 in this way, as in the future the process will take carbon dioxide generated by industrial activity from the atmosphere and lock it deep underground," added Professor Eastoe.

"It is why the government has protected the science budget. In particular it shows how financing core science facilities can lead to many different projects with valuable applications.

Liquid CO2 is increasingly being used industrially to replace common petrochemical solvents because it requires less processing and can be easily recycled.

The difficulty has been that in order to operate effectively as a solvent, carbon dioxide needs additives, many of which are damaging to the environment.

This latest development by an international team including scientists from Bristol led by Eastoe and a group from the University of Pittsburgh, United States, led by Professor Bob Enick, as well as ISIS scientists Dr Sarah Rogers and Dr Richard Heenan and others, provides a way forward.

The project has been funded by the UK Engineering & Physical Sciences Research Council (EPSRC) and the US Department of Energy to explore using high-pressure CO2 to extract residual oil retained in the pores of rock.

"The quest to find a chemical capable of modifying the properties of CO2 to make it suitable for widespread use as a solvent in enhanced oil recovery has been long," said Professor Enick.

"Previous advances have involved surfactants containing fluorine which, although highly soluble in CO2, are very environmentally damaging. The new additive, surfactant TC14, contains no fluorine at all and is a harmless hydrocarbon," he added.

CO2 offers an efficient, cheap, non-toxic, non-flammable and environmentally responsible alternative to conventional petrochemical solvents.

Even water as a solvent for example, comes with its own set of problems. After being used to flush out oil from rocks, it requires cleaning before it can be used again, whereas liquid CO2 can be re-used immediately.

The researchers used Sans2d, one of seven new neutron instruments built at the ISIS facility in a 145 million pounds expansion completed last year to help develop the additive. Designated TC14, this surfactant enables small pockets to form in the liquid CO2 called reverse micelles, causing the liquid to thicken.

Neutron scattering at ISIS allowed the structure of the reverse micelles to be studied in the CO2 as they formed under high pressure. The neutron instruments giving this molecular level viewpoint are often described as super-microscopes.

"Beams of neutrons are able to penetrate deep inside samples, giving unique information about the location and arrangement of the micelles at a molecular level," said ISIS scientist Dr Sarah Rogers.

"By altering the pressure in a specially constructed experimental cell, dissolved material can easily be separated and removed leaving the carbon dioxide for the next use. It would be difficult to look at this system using any other technique as the CO2 needs to be kept under high pressure. Only under the scrutiny of neutron beams can you fully reveal its actions and properties."

Professor Eastoe added: "Experiments on Sans2d are particularly fast and accurate in comparison to some older neutron scattering instruments. This development of neutron instrument technology is part of what makes ISIS a world-leading science facility.