The effects of residence time and gas temperature on LOI were
addressed in the pilot study of Ikeda et al. [3]. They reported that
the reduction of carbon in ash was about 20% with the in-furnace
blending method supplying bituminous coal to the lower burners,
compared to the out-furnace method. This blending method corre-
sponds with the present case, Case S-1. In the case of supplying
bituminous coal to the upper burners (Case S-3 in the present
study), carbon in ash increased. This coincides with the present
simulation results. Ikeda et al. interpreted these results to be due
to the longer residence time and higher temperature when burning
bituminous coal at the lower burners. The study with drop tube