The operation of the moving bed coal gasifier is strongly influenced by five parameters: steam feed (Fs)

oxygen feed (Fo)

carbon feed (FC)

bed height (H) and blast temperature (TB). These parameters interact closely

so that it is difficult to determine numerically the optimal operating conditions. On the basis of an analysis of the one-dimensional homogeneous model

this paper demonstrates the possible relations among these parameters. numerical computations indicate that an increase of 0.3m in the bed height can sometimes compensate for a decrease of 10-15K in the blast temperature without affecting the residual carbon in the ash and the heating value of the gas product. See Fig. 1. This paper suggests an energy-saving idea for decreasing both steam and oxygen feed at a slight increase of Tmax. For a constant feed of fixed carbon (coal charged

minus moisture

volatiles and ash)

a reduction in the steam feed can accelerate the gasification process

while a simultaneous decrease in the oxygen feed can sometimes keep the maximum temperature lower than the permissible value.