(246a) Transient Heat and Mass Transfer Model of a Solar Thermochemical Reactor for CO2 Capture

A dual–cavity solar thermochemical reactor for carbon dioxide capture using the CaO carbonation—calcination cycle is under development. During the first step of the cycle, the exothermic carbonation, a packed bed of CaO particles in the reactor captures CO₂ from a dilute stream such as from a power plant. In the second step, the endothermic calcination, the beam up reactor accepts concentrated solar energy through a windowless aperture at the bottom. The radiation is absorbed by the cavity walls and transferred via conduction to the reacting packed bed of particles in the outer cavity, releasing CO₂ in a concentrated stream and regenerating CaO. To support refinement of the reactor design, a transient heat and mass transfer model has been developed using ANSYS Fluent to solve the continuity, momentum, and heat transfer equations coupled to a custom Monte Carlo ray tracing routine that determines radiation heat transfer in the reactor cavity. Transient temperature and velocity profiles and chemical reaction conversion in the reactor are presented.