Coal-gasification kinetics derived from pyrolysis in a fluidized-bed reactor

Coal pyrolysis and gasification reactions were carried out in a fluidized-bed reactor (0.1 m i.d. by 1.6 m height) over a temperature range from 1023 to 1173 K at atmospheric pressure. The overall gasification kinetics for the steam-char and oxygen-char reactions were determined in a thermobalance reactor. The compositions of the product gases from the coal-gasification reactions are 30-40% H-2, 23-28% CO, 27-35% CO2 and 6-9% CH4 with heating values of 2000-3750 kJ m(-3). The heating value increases with increasing temperature and steam/coal ratio but decreases with increasing air/coal ratio. Our kinetic data derived from the two-phase theory on coal gasification in a thermobalance reactor and coal pyrolysis in a fluidized bed may be used to predict the product-gas compositions. (C) 1998 Elsevier Science Ltd. All rights reserved.