城市污泥与阳泉煤掺烧及污染物释放特性

Blending effect of municipal sludge on Yangquan coal combustion performance and pollutant release characteristics

利用热重—质谱联用仪研究了阳泉地区煤掺混城市污泥的燃烧及污染物排放特征,并探讨了燃烧过程中动力学特性。实验结果表明,污泥着火温度、燃尽温度均低于阳泉煤,但燃烧温度跨度广,反应速率慢;污泥的掺烧量影响燃烧特性,随着污泥掺烧量增加,混合样品的着火点降低,但综合燃烧特性指数也有所下降;当城市污泥掺混比例不大于20%时,燃烧过程SO_2和NO_x的释放特性与阳泉煤单独燃烧时相似,但掺烧污泥后NO_2的释放强度要低于阳泉煤单独燃烧的释放强度。采用积分法(Coats-Redfern)获得了燃烧反应的机理方程及活化能,发现燃烧反应级数随着污泥掺混比的增加反应活化能降低。

Coal and municipal sludge samples were collected from Yangquan,Shanxi. The cocombustion behavior and pollutant release characteristics of these two kinds of fuels and their mixtures were investigated by a thermo-gravimetric analyzer coupled with a mass spectrometer. In addition,the kinetic parameters were also calculated during combustion processes. The experimental results showed that the ignition temperature and burnout temperature of the municipal sludge were both lower than those of Yangquan coal,but the combustion temperature was wider and the reaction rate was slower.With the ratio increase of municipal sludge,the ignition point of the mixed sample decreased;however,the comprehensive combustion characteristic index（ S） also declined. When blendingsludge with Yangquan coal,the ignition point decreased and S also declined. When the added sludge was less than 20%,the release behavior of SO_2 or NO_x was similar with that from Yangquan coal combustion process,but the release intensity of NO_2 became weak. In addition,Coats-Redfern equation was adopted to calculate both reaction equations and activation energy. It was found that activation energy decreased with the increase of the sludge mixing ratio.