Devolatilization is a significant step in fluidized bed combustion or gasification of coal. Oxygen-enriched air can increase the efficiency of any coal combustion process. In this work, devolatilization of five Indian coals having volatile matter in the range of 31 to 41% has been studied in argon, air and oxygen-enriched air (containing 30% oxygen) under fluidized bed conditions at 1123 K and atmospheric pressure. The diameter of the coal particles varied between 4 and 9.5 mm. Correlations of devolatilization time with particle diameter have been developed. A correlation for the variation of...