A discrete-pore-size-distribution-based gas-solid model and its application to the CaO+CO2 reaction

Experimental data obtained in both atmospheric and pressurized thermogravimetric reactors indicate that carbonation is insensitive to the CO2 partial pressure in terms of final conversion and apparent carbonation rate. A new gas-solid model is formulated to describe the entire experimental carbonation history, with measured rate constant and pore size distribution data as input. The effective diffusivity in the product layer is the only fitting parameter, dependent on the evolution of the pores. The model is able to predict atmospheric and pressurized thermogravimetric reactor carbonation data with fitted activation energies of 215 and 187 kJ/mol for the limestone and dolomite tested. (C) 2007 Elsevier Ltd. All rights reserved.