Experimental and thermodynamic investigation on transfer of cadmium influenced by sulfur and chlorine during municipal solid waste (MSW) incineration.
Experimental and thermodynamic investigation on transfer of cadmium influenced by sulfur and chlorine during municipal solid waste (MSW) incineration.
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DOI：
10.1016/j.jhazmat.2007.08.054
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发表时间：
2008-05
影响因子：
13.6
通讯作者：
Yan‐guo Zhang;Yong Chen;A. Meng;Qinghai Li;Hefa Cheng
中科院分区：
文献类型：
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作者：
Yan‐guo Zhang;Yong Chen;A. Meng;Qinghai Li;Hefa Cheng
我们使用了两种方法来研究硫和氯化合物的影响转移的半挥发性重金属，镉，在城市固体废物（MSW）焚烧：实验使用管式炉反应器和热力学平衡计算。在850°C条件下，对我国典型城市生活垃圾（MSW）中含有和不含有硫和氯化合物的人工废弃物进行了燃烧，并对Cd在底灰、飞灰和烟气中的分配进行了定量研究。结果表明，元素态和还原态的硫化合物在焚烧过程中，由于局部还原环境的影响，能稳定以CdS形式存在的Cd，而氧化态的硫化合物会略微增加Cd的挥发。与此相反，氯化合物的存在下显着增加了镉的分配粉煤灰。化学平衡计算表明，硫与镉结合，并在低温（<700°C）下改变镉的形态，而氯通过形成挥发性CdCl 2显着增加镉的挥发，从而在400和1000°C之间分配到飞灰上。平衡计算结果还表明，SiO2-和Al 2 O3-含有矿物可以作为吸附剂稳定Cd作为凝聚相固体（CdSiO 3和CdAl 2 O 4）。这些研究结果提供了有用的信息，了解镉的分配行为，可以帮助发展的策略，以控制在垃圾焚烧过程中的镉挥发。
We used two approaches to investigate the impact of sulfur and chlorine compounds on transfer of a semivolatile heavy metal, cadmium, during municipal solid waste (MSW) incineration: experiments using a tubular furnace reactor and thermodynamic equilibrium calculations. Artificial wastes representative of typical MSW in China with and without the presence of sulfur and chlorine compounds were combusted at 850°C, and the partitioning of Cd among bottom ash, fly ash and flue gas was quantified. The results indicate that sulfur compounds in the elemental form and reduced state could stabilize Cd in the form of CdS due to local reducing environment, while sulfur in the oxidized forms slightly increased Cd volatilization during incineration. In contrast, the presence of chlorine compounds significantly increased the partitioning of Cd on fly ash. Chemical equilibrium calculations show that sulfur binds with Cd and alters Cd speciation at low temperatures (<700°C), while chlorine significantly increases the volatilization of Cd through formation of volatile CdCl2and thus its partitioning on the fly ash between 400 and 1000°C. The equilibrium calculation results also suggest that SiO2- and Al2O3-containing minerals could function as sorbents stabilizing Cd as condensed phase solids (CdSiO3and CdAl2O4). These findings provide useful information on understanding the partitioning behavior of Cd and can help development of strategies to control volatilization of Cd during MSW incineration.