Comparison of catalytic activity through gas-solid reaction models in CO 2 gasification of lignite with alkali metal salts and iron sulfate

Catalytic gasification of a low rank coal- Inner Mongolian lignite has been carried out with carbon dioxide. The gasification reactions were performed in a thermogravimetric analyzer at temperatures of 600°C to 900°C. The kinetic parameters were evaluated using three different gas-solids reaction models and the prediction ability of each model were compared. Among the models evaluated, the modified volumetric model was found to correlate best both the non-catalytic and catalytic gasification reactions. The theoretical models, homogeneous and shrinking-core models , were found to satisfactorily correlate gasification reactions for the non-catalytic and FeSO 4-catalyzed reactions. In case of alkali metal catalysts, the catalytic activity was mostly pronounced at a low temperature of 600 Ai and observed to decrease by 50 % as the temperature was increased to 700 Ai , and it remained nearly constant at temperature over 800 Ai . The order of catalytic activity was found to be: K2CO 3>Na 2CO 3>K 2SO 4>FeSO 4.