A Chemistry on the Volatility of Some Trace Elements during Coal Combustion and Pyrolysis

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• 作者：Jie Wang and Akira Tomita
• 刊名：Energy & Fuels
• 出版年：2003
• 出版时间：July 2003
• 年：2003
• 卷：17
• 期：4
• 页码：954 - 960
• 全文大小：240K
• 年卷期：v.17,no.4(July 2003)
• ISSN：1520-5029

文摘

Laboratory experiments were conducted to investigate the vaporization behavior of nine traceelements including beryllium, vanadium, chromium, manganese, cobalt, nickel, zinc, arsenic,and lead during coal combustion and pyrolysis below 1150 C. Zinc, lead, and arsenic exhibitedgreater volatility than the rest of the trace elements, and their vaporization behavior dependedon the atmosphere and heating rate. Zinc and lead highly volatilized during pyrolysis and rapid-heating combustion, while they only slightly volatilized in slow-heating combustion. Arsenicvolatilized during the rapid-heating combustion but almost entirely remained in the char or ashin the case of pyrolysis and slow-heating combustion. Thermodynamic analysis suggests thatcarbothermic reactions of zinc- and lead-bearing compounds promote the formation of metalliczinc and lead vapors. Interactions of arsenic with the mineral components in coal contribute tolittle vaporization loss of arsenic in the pyrolysis and slow-heating combustion probably becauseof the formation of thermally stable species such as ferric arsenide (FeAs) and calcium arsenate(Ca₃(AsO₄)₂).