Coal gasification to produce gaseous fuel such as CO and H-2 is well-known as one of the key technologies for utilization of coal. Coal gasification mainly involves two steps: the initial rapid devolatilization of coal to produce char, tar and gases and the subsequent gasification of the char produced. Char gasification, being the slower step, is believed to control the overall conversion process. It is, however, known that solid carbon called coke (soot) is formed from the volatiles produced during the initial devolatilization at high temperature above 1000degreesC. Since the gasification reactivity of the coke is expected to be rather low, it is important to examine if the coke is really formed and to estimate the gasification reactivity of the coke if it is formed. In this study it was clarified that the coke is actually formed at high temperature and high pressure from the equilibrium calculation and experiments using a miniature tubing-bomb reactor (mini-TBR.) and a pressurized drop tube furnace (PDTF). The ratio of coke to char was roughly 1 to 1 for the solid carbons prepared by the PDTF. The gasification reactivity of the coke was found to be 1/20-1/6 of the char when compared at 1200degreesC. SEM and TEM observations also clarified that the solid carbon obtained by PDTF was the mixture of char and coke. (C) 2004 Elsevier Ltd. All rights reserved.