Abstract:Staged incineration was carried out on laboratory-scale tube furnace for the sewage sludge incineration treatment. Partitioning, transformation and removal of Pb were investigated under different combustion conditions and four solid sorbents including CaO, Al2O3, fly ash and kaolin were added in sewage sludge incineration process in order to reduce the Pb emissions effectively. The calculation of thermodynamics equilibrium was conducted to identify the Pb removal simultaneously. Thermodynamic equilibrium calculation results indicated that Pb mainly volatilized as the form of PbO (g) during sludge incineration process. PbCl2 (g) was the main volatile substance in the presence of Cl compounds which can promote Pb volatilization. PbSO4 (s) generated while sulfide compounds existed, which would inhibit the volatilization of Pb during incineration. Stable compounds including (PbO)(Al2O3)(s), PbSiO3(s) and CaPbO4(s) were formed and the temperature of PbO(g) formation was delayed by adding the sorbents Al2O3, SiO2 and CaO. Al2O3 was more efficient for removal of Pb than SiO2 and CaO. The results of incineration experiments showed that the residue of Pb in incineration bottom ash had a decreasing trend with increasing incineration temperature and the proportion of reducible Pb fraction increased in the bottom ash, while that of residual fraction showed a descending trend. The increasing incineration time had little influence on the volatilization of Pb, but the proportion of Pb residual fraction decreased in thebottom ash. Pb would change from chloride states to the oxidation states as a result of the increasing moisture, which inhibited the volatilization of Pb chloride. With the increasing excess air coefficient, the residual rate of Pb decreased in the bottom ash. With the increase ratio of the solid adsorbent, the residual rate of Pb increased gradually and immobilized in the bottom ash. The CaO and Al2O3 were superior to fly ash and kaolin in the controlling of Pb volatilization.
刘敬勇, 孙水裕, 陈涛, 陆少游, 王玉洁, 谢武明, 杜青平, 杨佐毅, 李磊. 污泥焚烧过程中Pb的迁移行为及吸附脱除[J]. 中国环境科学, 2014, 34(2): 466-477.
LIU Jing-Yong, SUN Shui-Yu, CHEN Tao, LU Shao-You, WANG Yu-Jie, XIE Wu-Ming, DU Qing-Ping, YANG Zuo-Yi, LI Lei. Migration behavior of Pb and its vaporization control during sewage sludge incineration process. CHINA ENVIRONMENTAL SCIENCECE, 2014, 34(2): 466-477.