Effect of Char Formation Temperature on the Densification of a Bituminous Coal Char during Gasification

Abstract

It has been observed that some porous carbon particles shrink when oxidized under kinetically limited conditions, instead of reacting at constant diameter, as expected. This study was performed to determine whether or not char from PSOC 1451 coal prepared at different temperatures would also shrink during low-temperature gasification. Coal chars, formed at 1200 and 1600 K, were levitated in the electrodynamic balance and heated with a carbon dioxide laser. The 1200 K char did shrink, as observed in the previous study, while the 1600 K char reacted at constant diameter, as expected under the kinetically limited conditions. These results demonstrate that the time and temperature history of a char influence its behavior during subsequent oxidation.