Reburning study of superfine pulverized coal in high CO2 concentration.

Reburning combustion of coal in high CO₂ concentration is a new and competitive technology in the modern academic research area. In this paper, combustion of superfine pulverized coal in high CO₂ concentration of reburning is conducted in a drop tube furnace. The result reveals that reduction efficiency for superfine pulverized coal (21.30 μm) is the highest among all the other particle sizes at the working condition of low oxygen concentration and high reburning fuel fraction. Meanwhile, it is discovered there exists a stage for the particles (25–30% for 14.71 μm, 15–25% for 17.44 μm, 15–20% for 44.26 μm), within this stage, the increase of reburning fuel fraction doesn’t effectively promote NO reduction efficiency. With the increase of the temperature, NO reduction efficiency for the particle size doesn’t display the monotonous rising trend. NO reduction efficiency for the particle size of 17.44 μm ranks the second of all the particles, which indicates that the influence of CO on NO reduction is more important than the role of oxygen.