Modelling of entrained-bed pulverized coal gasifiers

An analytical model is formulated to describe the physical and chemical processes occurring in an entrained-bed pulverized coal gasifier. The important processes considered are: mixing of the cold coal-carrier-gas stream with the hot entraining gases, heat transport to the coal particles, the devolatilization of the coal particles to char and volatiles, the gasphase reaction of these volatiles with the entraining gases and the thermal cracking of the volatiles outside the particles. The solutions to the formulations are presented in the form of local properties as functions of particle residence time and inlet conditions. Application of this model is exemplified by correlating it with the data obtained in an entrained-bed coal gasifier in which pulverized coal is injected into hot combustion gases to produce a fuel gas of low heating value.