British engineers believe that by controlling the fossil fuel combustion process with tiny ceramic tubes, carbon emissions from power stations could be virtually eliminated.

Scientists at Newcastle University carried out research on a material known as LSCF, which possesses the remarkable property of being able to filter oxygen out of the air.

Tubes made of LSCF, which stands for Lanthanum-Strontium-Cobalt-Ferric Oxide, could allow pure oxygen to be delivered to power plants.

By burning fuel in just oxygen, it is possible to produce a stream of almost pure carbon dioxide, which has commercial potential for reprocessing into useful chemicals.

LSCF was originally developed for fuel cell technology, but chemical engineers Newcastle University, in collaboration with Imperial College London, recognised its potential for creating cleaner power stations.

The technology is currently being developed for gas-fired power stations, but the team hope that it could be adapted to coal and oil electricity generation.

Conventional gas-fired power stations burn methane in a stream of air, producing a mixture of nitrogen and greenhouse gases, including carbon dioxide and nitrogen oxides.

Separating out the gases is not practical because of the high cost and large amount of energy needed to do so.

However, the LSCF tubes would allow only the oxygen component of air to reach the combustion chamber, resulting in the production of almost pure carbon dioxide and steam, which can easily be condensed out as water.

The resulting stream of carbon dioxide could be siphoned off and piped to a processing plant for conversion into chemicals such as methanol, a useful industrial fuel and solvent.

The LSCF tubes look like small, stiff drinking straws and are permeable to oxygen ions – individual atoms carrying an electrical charge.

Crucially, LSCF is also resistant to corrosion or decomposition at typical power station operating temperatures of around 800°C.

Further testing before commercial applications

When air flows around the outside of the tubes, oxygen is able to pass through the wall of the tube to the inside, where it burns with methane gas that is being pumped through the centre of the tubes.

Laboratory testing on the ceramic tubes has been successful, and the design has attracted interest from the energy industry.

The Newcastle team is now carrying out further tests on the durability of the tubes, to confirm that they could withstand the conditions inside a power station combustion chamber for a reasonable length of time.

Although it has not yet been attempted, it should be possible to assemble a power station combustion chamber from a large number of the tubes, with space between them for air to circulate.

In theory, the technology could also be applied to coal and oil-fired power stations, provided that the solid and liquid fuels were first converted into gas. This operation would be relatively simple, but would add to the cost and complexity of running a power station.

"The cheapest way to dispose of waste carbon dioxide from combustion is to release it into the atmosphere," said Professor Ian Metcalfe, a member of the research team.

"We have been doing this since humans first discovered how to make fire.

"The technology we have developed may provide a viable alternative, although whether it is economical to introduce it will depend largely upon the carbon credit system that Governments operate in the future," he concluded.

Details of the research and development project are published today in two technical publications – Materials World and The Chemical Engineer.