采用沉降炉实验系统研究了O2/cO2燃煤气氛下醋酸钙、醋酸调质石灰石和木醋调质石灰石再燃脱硝性能,探索了CO2浓度、温度、再燃比、氧浓度、停留时间、SO2、氨氮比等反应参数对再燃和先进再燃脱硝的影响。结果表明:O2/CO2气氛下,提高CO2浓度有助于有机钙再燃脱硝反应。有机钙再燃和先进再燃脱硝适宜工况参数:温度范围1223~1373K、再燃比为14%~17%、再燃区入口氧浓度为3%左右、停留时间为0.8S,氨氮比为0.75。典型工况条件下,有机钙基本再燃脱硝效率为62.0%~82.7%,先进再燃脱硝效率88.3%~95.6%。醋酸和木醋调质石灰石再燃和先进再燃脱硝性能略优于醋酸钙。O2/CO2气氛下有机钙再燃在最佳脱硫温度下不能获得最大脱硝效率,先进再燃可以明显改善脱硝性能。最佳反应条件下木醋调质石灰石先进再燃脱硫脱硝效率分别为73.2%和94.8%。
The performance of NO reduction by rebuming with calcium acetate (CA), limestone modified by acetic acid (LMAA) and limestone modified by wood vinegar (LMWV) in simulated Oz/CO2 coal combustion gas was investigated using a drop tube furnace. The effects of operating parameters on nitric oxide reduction were explored, including CO2 concentration, temperature, rebuming fuel fraction, residence tim6, SO2 and [NH3]/[NO] molar ratio. The results show that the NO reduction efficiency increases with the rise of CO2 concentration in O2/CO2 combustion gas. The optimum operating parameters for basic reburning (BR)/advanced reburning (AR) with organic calcium obtained by the experiments include reburning zone temperature of 1223-1373 K, reburning fuel fraction of 14%-17%, 02 concentration of around 3% at rebuming zone inlet, residence time of 0.8 second and [NH3]/[NO] molar ratio of 0.75. Under typical experimental conditions, the denitration rates are 62.0%-82.7% and 88.3%-95.6%, respectively for BR and AR with the three types of organic calcium. The NO reduction performance of LMAA and LMWV is somewhat better than that of CA in BR and AR. SO2 with a concentration of 1 200 ~tL/L in the gas promotes the NO reduction in BR with the organic calcium slightly. The maximum NO reduction cannot coincide with the optimal desulfiu'ization temperature for organic calcium rebuming in O2/CO2 combustion atmosphere. However, advanced reburning under these conditions can improve NO reduction. The desulfurization and denitration rates are 73.2% and 94.8% respectively in AR with LMWV at the optimum reactive conditions.