Influence of micromilling on air conversion of pulverized coal fuel is under study. On the basis of these experiments, computational fluid dynamics methods are used to perform simulation determining the conditions of the process under study. Conversion of coarse coal in a medium of combustion products of fine coal with the following parameters: a flow rate of primary and secondary coal is 0.82; a corresponding air flow rate is 0.35; the excess ratios of primary, secondary, and total air are 0.8, 1.87, and 1.39; temperatures in the active zone are higher than 1 200 oC. According to the computational results for this regime, conversion for the primary and secondary coal is 100 % and 60 %, respectively, and the total conversion is »80%. The results obtained suggest that it is possible to increase the efficiency of coal combustion due to micromilling technologies as applied to oil-free ignition and torch illumination systems on steam pulverized coal boilers at TPPs.