(501g) Modeling of Carbonation Reaction Involving Dolomite-Based Sorbents

A number of highly reactive and attrition resistant regenerable MgO-based sorbents has been developed that are capable of removing CO2 from coal gas at Integrated Gasification Combined Cycle (IGCC) conditions. The reactivity of the ?best? sorbent formulation toward CO2 has been determined in High-Pressure ThermoGravimetric Analyzer (HPTGA) as well as high-pressure packed bed reactor. Samples of fresh and reacted sorbents were characterized by SEM/EDS mapping technique and all the phases were identified by XRD. The results indicate that the sorbent consists of a low reactivity inner core surrounded by a high reactivity outer shell.

A two-phase grain model was developed that is well consistent with SEM/EDS and XRD results. The model parameters were determined to fit the HPTGA carbonation reaction rate data at different temperatures. The model was applied to fit the sorbent performance though the cyclic carbonation/regeneration operation and determine the effect of cycling on the model parameters. The kinetic model was used to develop a packed-bed model to predict the sorbent performance in the high-pressure packed bed reactor.