Applicability of a coal combustion model was validated by comparing its predictions with experimental data of utility boilers. The coal combustion model had gasification and NO x reaction submodels and it was developed by using a small drop-tube-furnace (coal feed rate 0.6 kg/h). A turbulence combustion simulation program was developed by introducing the coal combustion model. The program was validated by comparing its predictions with 23 sets of experimental results which contained different plant, load and coal data. The temperature difference between simulated and experimental results was within 30• C at the furnace exit. The decreasing characteristic of coal burnout with increasing load was well predicted. The NO x emission difference between simulated and experimental results was less than 15%. The coal combustion model was judged applicable to utility boilers.