本文提出利用卤化铵盐NH4C1和NH4Br及H202对生物质稻杆焦进行化学浸渍改性,以提高其对燃煤烟气中汞吸附的化学活性;采用N2吸附/脱附、扫描电子显微镜/X射线能谱仪(SEM—EDS)对改性稻杆焦吸附剂进行了微观形貌表征。在固定床汞吸附实验台上,进行了稻杆焦吸附脱除模拟烟气中Hg0的实验研究和理论分析。研究结果表明,稻杆焦经改性后,其孔结构特性得到了较大改善,没有发生孔堵塞现象,其表面的片状突起结构比改性前更为丰富。稻杆焦改性后,其表面的Cl、Br、O含量明显增加;氧化和吸附汞的能力都有显著的提高。
Rice straw was treated by NH4Cl, NH4Br and H202 to activate its mercury adsorption in coal-fired flue gas. The prepared biomass chars were characterized by means of nitrogen (N2) adsorption/desorption, and scanning electron microscopy/X-ray energy dispersive spectroscope (SEM-EDS). Experimental studies on Hg removal in simulated flue gas were investigated in a fixed bed adsorption reactor system. The nitrogen (N2) adsorption/desorption results show that there is a great improvement on the pore structure of the modified biomass chars. The SEM observation displays that the pores on the rice straw char are not blocked after modification. The EDS analysis confirms the facts that Br, Cl and 0 content on rice straw char surface increase after modified by NH4Cl, NH4Br and H2O2. The experiments indicate that mercury adsorption and oxidation capacities of the treated rice straw char rise considerably.