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

Abstract

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% CO 2 and 6–9% CH 4 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.