The Fluent software was applied to carry out numerical simulation on combustion of a 330 MW unit tangentially pulverized coal fired boiler in air(O_2/N2=21%/79%)and oxygen-enriched(O_2/CO_2=21%/79%

O_2/CO_2=25%/75%

O_2/CO_2=30%/70%

O_2/CO_2=35%/65%)atmosphere.The temperature in the furnace center area

the radiation intensity

the concentration distribution of O_2

CO

and NO_xin different atmospheres were compared.The results show that

when the O_2 concentration is 21%

the furnace temperature during the oxygen-enriched combustion is lower than that during the air combustion

meaning the radiation intensity is weaker than that in the normal air atmosphere.The CO_2 emission in O_2/CO_2 atmosphere is much higher than that in the conventional air combustion.The NO_xformation is greatly lower than that in the air atmosphere.When the O_2/CO_2 ratio increases

the pulverized-coal combustion in the furnace gets stronger

leading to an acceleration in the combustion speed

thus the temperature in the furnace center area and the radiation intensity increases.Therefore

the NO_xformation and the CO_2 concentration grows

which makes the NO_xand CO_2 be easy to be captured.