NOx emission characteristics of superfine pulverized anthracite coal in air-staged combustion

•Staged combustion of anthracite coal for superfine pulverized coal is carried out.•NOx trend of dav=6.77μm is obviously different in fuel-lean unstaged combustion.•Comparison of NOx abatement in single staged combustion is made between five particle sizes.•The data of NOx reduction efficiency of multi air staged combustion is summarized.•NOx reduction efficiency of superfine pulverized coal in multi air staged combustion is found to be higher. Superfine pulverized coal combustion is a new pulverized coal combustion technology that has better combustion stability, higher combustion efficiency, and comprehensive cost-effective operation. In this paper, the experiment of YQ anthracite coal combustion was carried out on an electrically heated drop tube furnace. Meanwhile, single air staged and multi air staged combustion were both adopted to understand NOx emission behaviors and analysis of mechanism and reaction pathways of each experimental phenomenon was proposed as well. The results indicate that the NOx reduction efficiency of superfine pulverized coal (22.5–32%) in single staged combustion is higher than that of regular particle size (10%). The NOx abatement in multi air staged combustion is greater than that in single air staged combustion. In multi air staged combustion, the NOx reduction efficiency of superfine pulverized coal is superior to that of regular size, which may be due to the reaction mechanism where further penetration and adsorption of NOx takes place in the inner pores. Particle burnout in multi staged combustion ratio was found to be irrelevant to the operating conditions. The findings of this article will provide useful data for the subsequent experiment to investigate into the mechanism of pure NO–char reduction and for the basis of W-flame furnace operation.