燃煤烟气汞排放与控制研究进展

近年来,煤燃烧烟气汞排放加剧。针对燃煤中汞的形态分布以及各种影响因素进行分析和综述,对炉内脱汞和烟气汞排放的控制方法的原理和技术进行了总结和分析。

Review on the research progress of the mercury emission in flue gas in coal burning

This paper intends to make a review on the research progress of the mercury emission in flue gas in coal burning.As is known,mercury is known for its hypertoxicity,volatility and cumulativeness.To reduce and even get rid of such harmful effects of mercury on human body and environment, wide research has been done in the world in recent years,particularly in Asia, the most seriously polluted area in the world,for it is one of the continents fastest in accelerated industrialization.Mercury pollution and contamination can be summarized in the form of its distributions,such as Hg0,Hg2+ and HgP in the coal fire flue gas,which can be determined by the relevant temperatures,Cl concentration,other contents in flue gas,coal chips,combustion devices,etc.The research results reveal that mercury can be removed by injecting adsorbents in the furnace.Since the commonly-used air pollution control systems can help to obtain different Hg removing results in various complicated ways,such as injection of adsorbents,the activated carbon or modified activated carbon absorption.Of all the ways,modified activated carbon absorption displays greatest efficiency on Hg removal though its cost is high.Catalytic oxidation technology by means of the action of SCR and other catalysts has also been tested to transfer Hg0 to Hg2+ with a purpose to improve the Hg removal efficiency.Other novel mercury control methods are also under study,such as low temperature plasma,ozone and UV irradiation,and so on.Comparing different technologies,we prefer to recommend the general integrated air pollution technology,such as bag-type dust collector with adsorbent injection or catalytic oxidation.The kinds of cheap Hg adsorbents,such as the modified fly ash should also be recommended.The next best available methods,just followed by flue gas desulfidation,are the catalysis,for example,SCR de-NOx,which can be used to oxidize Hg.Thus,it can be seen that the above review helps to effectively control the emission of Hg in coal burning.