【摘要】 用恒温水浴中汞渗透管的汞蒸气发生装置以及烟气主要气体成分模拟烟气条件,在小型固定床试验台上开展天然沸石、膨润土和蛭石及其化学改性剂作为吸附剂脱除气态汞的试验研究。经NaCl溶液改性后的钠型沸石对汞的吸附能力有所提高,但与活性炭相比,还有一定差距。随Hg0入口浓度增加,钠型沸石吸附量增加;吸附温度升高,其吸附量显著降低,呈现典型的物理吸附特征。对膨润土和蛭石利用表面活性剂改性后,其单位吸附量均有所增加,对单质汞的吸附均呈现明显非线性,主要靠表面物理吸附作用。用MnO2、FeCl3金属氧化物对矿石样品进行化学改性后,吸附时间大为延长,原因在于吸附过程不再是单纯的物理吸附,而在吸附剂表面发生了化学反应,化学吸附过程有效增加了吸附能力。因此,可进一步通过改变化学浸渍试剂,继续提高改性吸附剂的吸附能力。更多还原

【Abstract】 A laboratory-scale packed-bed reactor system is used to screen sorbents for their capability to remove elemental mercury from various carrier gases. Experiments were carried out in a mercury sorption facility composed of mercury permeation tube embedded in an isothermal water bath and simulated flue gas compositions. The characteristics of mercury sorption by natural zeolite, bentonite, vermiculite and chemically modified sorbents were experimentally tested. Natural zeolite sorbents were chemically treated with NaCl solution; natural bentonite and vermiculite sorbents were treated with the organic active solution by the incipient wetness technique. Treatment with chemical solutions has been shown to produce a moderate increase of capacities compared with natural sorbents for mercury removal, but it still had much difference between Activated carbon and these sorbents. The results obtained suggested that their sorption mechanism should be described as a sole physisorption. It also has been shown that significant improvement of removal efficiencies with metal oxides MnO2 and FeCl3 impregnation onto natural sorbents. It is clear that they had strong chemical affinity towards mercury. Therefore, the adsorption mechanism should be the combination of phisisorption and chemisorption, and chemical reactions may further enhance their mercury capture performance. It certainly deserves a continuous and further exploration.更多还原