Decarbonation rates of cycled CaO absorbents

Decarbonation rates of cycled CaO sorbent were measured for a wide range of particle sizes (0.25-4 {mu}m), temperatures (747-830{sup o}C), and relative CO{sub 2} concentrations (0-95%). The decarbonation rate was found to decay exponentially with an increase in partial CO{sub 2} pressure that can be explained by assuming CaO nuclei formation is the rate-limiting step. A differential particle model using two variable parameters was successfully applied to fit the experimental data. An approximate analytical expression is put forward for the decarbonation rate as a function of sorbent texture, temperature, CO{sub 2} pressure, particle size, and Sherwood number. 24 refs., 6 figs.