July 22, 2009

Researcher develops cleaner CO2 capture

Separating carbon dioxide from its polluting source may soon be cleaner and more efficient, research at a California lab indicates.

A Lawrence Livermore National Laboratory researcher developed a screening method that would use ionic liquids -- a type of molten salt that liquefies under the boiling point of water -- to separate carbon dioxide from its source, the Livermore, Calif., lab said Wednesday in a release.

The method is cleaner, more viable and more stable than what is available now, and could enhance significantly the efficiency of the CO2 capture process, the research indicated.

Coal plants with commercial CO2 capture capability use processes based on chemical absorption with a general-purpose solvent, monoethanolamine, which scientists said is non-selective and corrosive, requires using large equipment, and effective only under certain conditions.

Chemists were attracted to ionic liquids because they are solvents with almost no vapor pressure and do not evaporate, even under high-temperature conditions, the research facility said.

LLNL scientist Amitesh Maiti's work involved a strategy that can reliably screen any solvent, including an ionic liquid, for high CO2 capture efficiency.

It's a great advantage to have a method that can quickly and accurately compute CO2 solubility in any solvent, especially under the range of pressures and temperatures as would be found in a coal-fired power plant, Maiti said. With ionic liquids serving as the solvent, the process could be a lot cleaner and more accessible than what is used today.