A Model of Transient Thermal Transport Phenomena Applied to the Carbonation and Calcination of a Sorbent Particle for Calcium Oxide Looping CO2 Capture

A numerical model coupling transient radiative, convective, and conductive heat transfer, mass transfer, and chemical kinetics of heterogeneous solid–gas reactions has been developed for a semitransparent, non-uniform, and non-isothermal particle undergoing cyclic thermochemical transformations. The carbonation–calcination reaction pair for calcium oxide looping is selected as the model cycle because of its suitability for solar-driven carbon dioxide capture. The analyzed system is a single, porous particle in an idealized, reactor-like environment. The model is used to investigate two cases distinguished by the length of the carbonation and calcination periods. The carbonation–calcination process for a single particle is shown to become periodic after three cycles.