褐煤半焦脱除燃煤烟气中元素态汞的试验研究

Experimental study on lignite semi-coke sorbents for elemental mercury removal from flue gas

为制备廉价的燃煤烟气中气态Hg0污染物的吸附材料,在小型固定床反应器上对3种原料褐煤半焦(NM-SC,SX-SC,SD-SC)、两种高锰酸钾改性半焦(Mn-SC,Mn-H-SC)的除汞性能进行试验研究。结果表明:3种原料半焦的除汞效率均随吸附温度的升高而降低,呈现出典型的物理吸附特征;NM-SC的孔隙结构最为发达,在低温时的除汞效率明显高于另外两种原料半焦;改性半焦Mn-SC和Mn-H-SC低温时的除汞效率较差,但高温时的除汞效率远高于NM-SC,呈现出典型的化学吸附特征,其中Mn-H-SC在140℃时的除汞效率可长时间稳定在80%左右;增加吸附剂用量,可提高Mn-H-SC的除汞效率;增加Hg0初始浓度会提高Mn-H-SC的单位质量汞容积量。

In order to produce lower price adsorbents for gaseous Hg° in flue gas, The mercury removal efficiencies of three kinds of virgin lignite semi-coke and two kinds of potassium permanganate modified semi-coke were investigated using a bench-scale fixed-bed apparatus. The results indicate that the mercury removal efficieneies of virgin semi-coke decreases as the adsorption temperature rising,which shows typical physical adsorption characteristic;NM-SC has the highest BET surface area and total pore volume with microporous structure, which shows much higher mercury removal efficiency than those of the other two kinds of virgin semi-coke at low temperature ; The mercury removal efficiencies of Mn-SC and Mn-H-SC are poor at low temperature,but much higher than that of NM-SC at high temperature, presenting typical chemical adsorption characteristic. In addition, mercury removal efficiency of Mn-H-SC can keep stable at around 80% for a long time when the adsorption temperature is 140 ℃ ;The mercury removal efficiency and volume quantity in unit mass of Mn-H-SC are in direct proportion with adsorbent dosage and Hg° initial concentration respectively.