Occurrence and volatility of several trace elements in pulverized coal boiler

Abstract： The contents of eight trace elements(Mn, Cr, Pb, As, Se, Zn, Cd, Hg) in raw coal, bottom ash and flyash were measured in a 220 t/h pulverized coal boiler. Factors affecting distribution of trace elements wereinvestigated, including fly ash diameter, furnace temperature, oxygen content and trace elements' characters. Onecoefficient of Meij was also improved to more directly show element enrichment in combustion products. Theseelements may be classified into three groups according to their distribution: Group 1: Hg, which is very volatile.Group 2: Pb, Zn, Cd, which are partially volatile. Group 3: Mn, which is hardly volatile. Se may be locatedbetween groups 1 and 2. Cr has properties of both group 1 and 3. In addition, the smaller diameter of fly ash, themore relative enrichment of trace elements( except Mn). The fly ash showed different adsorption mechanisms oftrace elements and the volatilization of trace elements rises with furnace temperature. Relative enrichments of traceelements(except Mn and Cr) in fly ash are larger than that in bottom ash. Low oxygen content can not alwaysimprove the volatilization of trace elements. Pb is easier to form chloride than Cd during coal combustion. Traceelements should be classified in accordance with factors. 作 者： HUANG Ya-ji    Jin Bao-sheng    ZHONG Zhao-ping    XIAO Rui    TANG Zhi-Yong    REN Hui-feng   作者單位： HUANG Ya-ji,Jin Bao-sheng,ZHONG Zhao-ping,XIAO Rui,TANG Zhi-Yong(Education Ministry Key Laboratory on Clean Coal Power Generation and Combustion Technology, Southeast University, Nanjing 210096, China)

REN Hui-feng(Thermoelectric Power Plant of Yangzi Petrochemical Co. , Nanjing 210002, China) 

期 刊： 環境科學學報(英文版)  ISTICSCI   Journal： JOURNAL OF ENVIRONMENTAL SCIENCES  年，卷(期)： 2004, 16(2)  分類號： X784  Keywords： occurrence    volatility    relative enrichment    trace element    group of elements