Hazard Control of NOx in Hot Stove

Hazard control of NOx is very important for the long life of hot stove shell and environmental protection. NOx concentrations during different operation periods of hot stove were calculated according to thermodynamical and dynamical analyses. The results were verified by the previously measured data. Then, the influence of hot stove operation parameters on NOx concentration and the mechanism of liquid water formation in hot stove were studied. The results indicated that in gas period, the dome temperature should be controlled below 1420 °C in order to decrease NOx emission. In the case of banking operation, NOx concentration was about 40—60 times higher than that in gas period. Hence, reasonable measures should be taken to reduce banking operation, especially in the situation of large excess air ratio. Since NOx formed during the whole operation process, the most effective way of preventing liquid water and HNO3 generation is to control the pipe and shell temperature, which should be higher than the condensation temperature of water vapour. The condensation temperature should be considered as the design temperature of pipe and shell for hot stove.