| Abstract Scope |
Chemical looping combustion (CLC) is an alternative concept being explored to generate energy while enabling the high efficiency capture of CO2 as a process byproduct. In CLC process, oxygen carriers are typically subjected to repeated redox environments to exchange oxygen. Most oxygen carriers are metal-oxide based, with hematite being representative of this type. In the reducing reactor, oxygen is removed from carrier particles, while in the oxidizer, oxygen is chemically taken back within the carrier particle. On the oxygen carrier’s surface, oxygen exchange during reduction takes place first by adsorption and dissociation (ionization), followed by diffusion; while oxidation is conducted by diffusion, deionization, then desorption. In this work, timing of these stages occurring on natural hematite particles during redox-triggered phase transformations was investigated by a combined visual and “semi-calorimetric” approach using a custom-designed high temperature environmental optical microscope. |