CHEMICAL LOOPING

Chemical looping is a process that involves exposing solid or liquid materials to alternating environments—typically oxidizing and reducing gas atmospheres—to selectively absorb or produce a particular product. At the energy research facility, we work with chemical looping combustion (CLC) and a variant known as chemical looping with oxygen uncoupling (CLOU). Chemical looping combustion is an energy production technology that achieves inherent capture of CO₂ with very little energy penalty. It works by cycling metal oxide-based "oxygen carrier" particles between two fluidized bed reactors. In one reactor, fluidized by air, the active metal is oxidized. At the outlet to that reactor, gas and particles are separated in a cyclone and the oxidized metal particles are transferred to the other reactor, which is typically fluidized with steam. The oxygen-depleted air is exhausted, which therefore achieves separation of oxygen—which has been transferred to the metal oxide—and nitrogen. The oxygen of the metal oxide then reacts with solid or gaseous fuel (e.g. coal, biomass, natural gas), in effect achieving combustion to produce CO₂ and water vapor. Because the nitrogen has been separated, the resultant product gas after condensation of water is essentially pure CO₂. CLC is a clever way to achieve carbon capture while generating energy without the need for expensive and energy-intensive air separation systems required for other CO2 capture technologies.

At the Advanced Energy Systems Research Facility, we use the Dual Fluidized Bed Reactor for chemical looping studies.