It's more efficient than existing techniques

Jul 23, 2009 13:50 GMT  ·  By
Making Jet fuel by scrubbing CO2 from the air would allow aviation to continue in a low-carbon economy
   Making Jet fuel by scrubbing CO2 from the air would allow aviation to continue in a low-carbon economy

Experts from the US Department of Energy's (DOE) Lawrence Livermore National Laboratory (LLNL) have recently proposed a new method of separating carbon dioxide from the emission pertaining to fossil fuel-powered plants, which is both more efficient and cleaner than the existing one. The new screening method involves the use of ionic liquids, which are, essentially, special salts that become liquid at temperatures under 100 degrees Celsius, the boiling point of water. Details of the innovation appear in the latest issue of the new, chemistry and sustainability-focused journal ChemSusChem.

The capture process, namely the extraction of carbon dioxide from the other gases in plant-generated smoke, is the most essential part of the whole carbon-capture and -sequestration process (CCS), which is now widely touted as an effective solution of reducing pollution in the short term. In this process, the dangerous greenhouse gas is separated from all other constituents, and then directed to underground storage facilities, where isolation prevents it from spreading into the atmosphere.

The existent methods, which make use of the general-purpose solvent monoethanolamine (MEA), is only marginally effective at moderate CO2 pressures, and even less so at high pressures. Additionally, the process is corrosive and non-selective. Using the 75-year-old solvent requires bulky machines that are very expensive to purchase, operate and maintain. The reason why ionic liquids recently started getting a lot of interest is the fact that they do not evaporate even under high temperatures, and also because they are solvents with almost no vapor pressure.

“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. With ionic liquids serving as the solvent, the process could be a lot cleaner and more accessible than what is used today,” LLNL scientist Amitesh Maiti, whose study appears on the cover of the journal, explains.

“Each new experiment costs time and money and is often hindered because a specific ionic liquid may not be readily available. By creating a computational tool that can decipher ahead of time which ionic liquids work best to separate CO2, it can be a much more efficient process when field tests are conducted,” he concludes.