论文部分内容阅读
为了考察燃料燃烧过程中重金属的迁移转化规律,对污泥、煤与木屑及其混合物在不同温度下氧气中燃烧灰渣中的重金属元素进行分析。结果表明,燃料中重金属在高温燃烧时表现出不同的挥发特性,大部分元素随着温度的升高挥发率增加,其中Cd、Pb和Zn元素挥发性较强,Cr、Cu和Ni挥发性较弱。污泥与木屑混合燃烧灰渣仍以污泥灰为主,重金属含量与污泥灰相近,污泥中混入煤后使灰中大部分重金属含量有所降低。燃烧过程会改变重金属存在形态,污泥与煤原料中以酸溶态和可还原态存在的重金属含量较高,具有较强的生物有效性和迁移性,而燃烧灰渣中酸溶态和可还原态含量显著下降,混合燃烧灰渣中除As外的其他重金属几乎全部以残渣态存在,其含量达到90%以上,焚烧过程有效降低了燃料灰渣中重金属的生物毒性。
In order to investigate the law of heavy metal transport and transformation during fuel combustion, the heavy metal elements in the ash from combustion of sludge, coal, wood chips and their mixtures in oxygen at different temperatures were analyzed. The results showed that the heavy metals in fuel exhibited different volatilization characteristics at high temperature combustion. Most of the elements increased their volatilization rate with the increase of temperature. Among them, Cd, Pb and Zn were more volatile, while the volatiles of Cr, Cu and Ni were more volatile weak. Sludge mixed with sawdust is still dominated by sludge ash, heavy metal content and sludge ash are similar, sludge mixed with coal to make most of the ash content of heavy metals decreased. The combustion process will change the existing form of heavy metals, sludge and coal materials in the acid soluble and reducible state of heavy metal content is high, with strong bioavailability and mobility, and combustion of ash acid and soluble The content of reduced state decreased significantly. The content of other heavy metals except As in mixed combustion ash residue was almost in the residual state, and the content reached more than 90%. The incineration process effectively reduced the biological toxicity of heavy metals in fuel ash.