燃煤电厂PM_(10)颗粒痕量元素富集与粒径关系统计研究

Relation between trace element enrichment and PM_(10) diameter from coal-fired power plants

煤燃烧带来的痕量元素排放是一个长期的环境问题。以PM10为主的细颗粒飞灰对痕量元素有较强的富集作用,且可以随着空气进入呼吸道,对人体危害很大。为了更好地理解痕量元素在细飞灰上的富集规律,该文通过对现有文献的广泛收集和整理,并通过统计分析研究了PM10飞灰颗粒粒径对Hg、Pb、As、Se、Cr、Cd、Cu、Co、Ni、Be 10种痕量元素富集的影响,得到了飞灰颗粒粒径与痕量元素富集关系的经验公式,利用这些经验公式可以对燃煤电厂与PM10相关的痕量元素排放情况进行初步判断。分析发现:PM10飞灰对痕量元素的富集作用强弱程度与痕量元素的挥发性呈正相关,其中Hg、Pb、As、Se、Cd、Cr 6种挥发性元素随着PM10飞灰粒径的减小富集程度增加,且PM2.5范围内的飞灰颗粒对痕量元素富集作用受颗粒粒径的影响最为显著;Cu、Co、Ni、Be 4种非挥发性元素在PM10范围内的飞灰颗粒上体现出较弱的富集作用,且受颗粒粒径影响不明显。

Trace element emissions from coal-fired power plants are a key long-termed environmental problem. PM10-based fine particles are highly enriched with trace elements that can go into the respiratory tract, which is very harmful to human health. The mechanism of trace element enrichment on fine particles was studied by establishing a database describing trace element hehavior in power plants burning pulverized coal from a comprehensive literature survey. Statistical analyses were then conducted to investigate the impact of PM^0 particle diameter on the enrichment of trace elements including Hg, Pb, As, Se, Cr, Cd, Cu, Co, Ni and Be. Empirical equations show that the enrichment on PM10 isdirectly linked with the trace element volatility. For six volatile elements, Hg, Pb, As, Se, Cd, Cr, the enriehment on PM10 increases as the particle size decreases, but for nonvolatile elements, Cu, Co, Ni, Be, the enrichment on PM20 is not obvious and is not influenced by the particle size.