Chemical looping is an advanced technology that offers several advantages over traditional combustion. In a chemical-looping system, a metal oxide, such as an iron oxide, provides the oxygen for combustion. The metal oxide releases its oxygen in a fuel reactor with a reducing atmosphere, and the oxygen reacts with the fuel. The reduced metal cycles back to an oxidation chamber where the metal oxide is regenerated by contact with air. The metal oxide is then reintroduced into the fuel reactor, thus completing the loop. Since CO2 separation occurs simultaneously with coal conversion, chemical looping offers a low-cost scheme for carbon capture. The process can produce power, synthesis gas, or hydrogen in addition to high-purity CO2.
http://www.fossil.energy.gov/news/techlines/2013/13005-OSU_Researchers_Advance_Chemical_L.html
Interesting. Thanks.