Carbon capture from fossil fuel-fired power plants is an energy-demanding and costly business – whether it involves the removal ofCO2 prior to combustion or its separation afterwards. This is why researchers have been working to develop alternative methods. One such is Chemical Looping Combustion (CLC). This process uses a metal oxide circulating across two reactors.
The oxide carries oxygen taken from air introduced to the first reactor, while fuel is introduced into the second. Here the fuel is oxidized in a reduction process resulting in CO2 and steam. There are thus two exhaust streams, both of which can be used to generate energy – nitrogen from the first reactor, and CO2 and steam from the second. The water is easily separated by condensation, leaving more or less uncontaminated CO2. Marie Bysveen at SINTEF Energy Research believes that this process has the potential to become more energy efficient than current exhaust gas cleaning.