Study offlue gas emission and improvement measure in a natural draft dry-cooling tower withflue gas injection under unfavorable working conditions

Özet

In this paper, we observed thatflue gas from a natural draft dry-cooling tower (NDDCT) withflue gas injectioncould not be discharged smoothly under unfavorable working conditions (e.g., when the louvers are closed inwinter), which may have caused severe corrosion on the inner shell of the cooling tower. In light of this issue, weproposed an improvement measure. On the basis of the computationalfluid dynamics (CFD) method, we es-tablished a numerical model for NDDCT withflue gas injection to predict theflowfield and pollutant diffusion.We simulatedflue gas emissions for a NDDCT withflue gas injection under normal and unfavorable workingconditions. The results showed that the air massflow rate and heat rejection of the cooling tower decreasedsignificantly, and the airflow in the cooling tower became disorganized when the louvers were closed underunfavorable working condition. Compared with normal working conditions, the pollutant concentration on theinner shell of the cooling tower increased by 1.5 times under unfavorable working conditions. After increasingthe height offlue gas outlet, the pollutant concentration on the inner shell of the cooling tower decreasedobviously.