改性氢氧化钙吸附脱除模拟烟气中汞的试验研究

对氢氧化钙进行了2种改性，并在小型模拟燃煤烟气Hg吸附和形态转化试验台上研究其对模拟烟气中Hg的脱除效果。结果表明：Ca(OH)2对单质汞的吸附主要是物理吸附，低温有利于汞的吸附；SO2和HCl均可以促进Ca(OH)2对汞的吸附，HCl对汞的氧化能力强于SO2，促进作用更明显；KMnO4改性后的Ca(OH)2在基本气体中可以将大部分的Hg0氧化为Hg2+，在有SO2或HCl存在的条件下可以脱除烟气中50%以上的Hg，改性后的吸附以化学吸附为主；利用AgNO3改性后的Ca(OH)2对汞的吸附能力极大增强，脱除效率可达90%，主要原因是银汞齐反应的发生，该法可望实现吸附剂的再生和Hg的回收利用，具有实际应用的前景。

Experimental Investigation on Absorption of Hg in Simulated Fuel Gas by Modified Ca(OH)2

Two kinds of modified adsorbents based on Ca(OH)2 were experimentally prepared. Then their adsorption capacities to mercury in simulated flue gas were investigated on a beach-scale fixed bed set-up. The results show that the adsorption of Ca(OH)2 to Hg0 is mainly controlled by physical mechanisms, and low temperature is beneficial to it. SO2 and HCl both promote the adsorption ability of Ca(OH)2. The promotion of HCl is more significant than that of SO2 due to it’s stronger oxidation ability to Hg0. KMnO4 modified Ca(OH)2 can oxidize large amount of Hg0 into Hg2+ in the base line flue gas system and adsorb more than 50% of the total Hg at the presence of SO2 or HCl, which is mainly controlled by chemiadsorption mechanisms. When modified by AgNO3, an amalgamated silver reaction may occur on the surface of Ca(OH)2 so that a 90% mercury removal rate then reaches. It can not only have stronger adsorption ability to flue gas mercury, but also can be potentially regenerated and make mercury reclaimed.