燃煤过程中痕量重金属的形态与分布研究

Research on the Morphology and Distribution of Trace Heavy Metals During Coal Combustion

采用化学热平衡分析方法研究了不同煤种的燃烧过程中痕量元素的化学形态及其分布。选用的煤种为河南平顶山烟煤、河南焦作无烟煤和贵州六盘水贫煤3个煤种,分析的痕量元素为Pb、Cd和Cr3种痕量重金属元素。在400K～2000K温度范围内,比较讨论了3种元素在氧化性和还原性气氛中的化学形态和物理相。结果表明:在燃煤过程中,Pb、Cd和Cr都是不易挥发的元素,他们的挥发性大小依次为Cd>Pb>Cr;在还原性气氛下,高温时主要以气态单质存在;烟煤与贫煤的分析结果一致,而无烟煤的分析结果在低温时存在差异。

The chemical morphology and distribution of trace elements during coal combustion are studied based on the chemical thermal equilibrium analysis. The analyzing trace heavy metals are Pb、Cd and Cr with the raw coals include Pingdingshan bituminous coal, Jiaozuo anthracite coal, and Liupanshui lean coal. The chemical morphology and physical phase of these three elements are compared under the oxidizing and reducing atmosphere in a temperature range from 400K to 2000K. The results show that the order of volatility of the three elements is Cd>Pb>Cr, and they all are not easy to volatilize. Under the reducing atmosphere, when the temperature is high, they are all existed in the elementary gas. The analysis results of bituminous coal and lean coal are same, but there are some differences with analysis results of anthracite coal in low temperature. Figs 6, tables 3 and refs 5.