EFFECT OF CHAR FORMATION TEMPERATURE ON THE DENSIFICATION OF A BITUMINOUS COAL CHAR DURING GASIFICATION

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