Mars extracts

A chemical process initially developed to study the biological environment on Mars could be used on Earth to help extract oil from tar sands.

The method, developed by researchers at Imperial College London, involves using extraction-helping materials called surfactants.

Imperial Earth science engineer Mark Sephton, one of the developers, said these surfactants were originally designed for use on ExoMars, Europe’s next robotic mission with NASA in 2018, to liberate organic matter from rock on Mars.

Sephton said his background in petroleum told him the technique could also be used in the process of extracting oil from tar sands, which he said hold two-thirds of the world’s remaining oil resources. (The Engineer, December 2008).

‘If you look at satellite images of the Athabasca Oil Sands in Canada, there are massive amounts of oil there but it is degraded and it is stuck to sand,’ he said. ‘What they do is blast large amounts of hot water at this sand to remove the oil and minerals and separate the two fractions. This water is then partially contaminated and left to settle for a few years and what we can do is add our surfactant solution to the water, initiate precipitation, and because of the characteristics of the surfactants, we can clean these up pretty much on demand.’

The water would then be ready for re-use — saving companies from wasting fresh supplies. ‘Because of the volumes involved and the economics involved, a very small increase in efficiency gives you a major financial boost in these circumstances,’ he added.

Sephton and a post-doc colleague will spend the next 12 months refining the process originally designed for Mars for the tar-sands application. He said the technology has already generated interest from industrial partners and he is currently in talks with some of them. ‘The technology is quite elegant,’ he said. ‘You require nothing more than solution equipment and some means of raising the temperature of the water. All this infrastructure is present in oil fields anyway.’

Sephton said there are no technical barriers remaining to solve. The hard part, he added, was discovering the right surfactants to use.

The surfactants originally developed for the extraction system on Mars were designed to remove living organic molecules and fossil organic molecules from rocks.

‘It sounds very simple but in practice it is quite difficult because fossil organic molecules of course don’t like water, whereas living organic molecules like water,’ Sephton explained. ‘In the lab, generally what we do is use organic solvents for fossil molecules and water-based solvents for biomolecules. So to produce a solvent that does both, a sort of universal solvent was quite tricky.’

Sephton said that he and his colleagues settled on using a surfactants solution based on polysorbates, which is an emulsifying agent that is used in ice cream.

‘We put it into water and used a specific concentration,’ he said. ‘We found out when we extracted our range of compounds that the biomolecules went into the water phase and the fossil molecules went into these little enclosures formed by the surfactants. So we created a universal solvent.’

Sephton is confident that within 12 months he and his colleagues will develop a procedure that is commercially viable for the tar-sands industry. He believes the technology could make a big impact.

‘We talk about the supply of energy, but the supply of water is another real environmental and economic concern,’ he said. ‘To remove that particular bottleneck is a particular advance.’

Siobhan Wagner