为降低纳米ZnO脱硫剂的应用成本及避免对环境产生二次污染,本文对均匀沉淀法制备的铁掺杂纳米ZnO脱硫剂(FZ5.0)进行了硫化和再生循环试验研究,并利用XRD、XPS和TEM等表征手段对FZ5.0的硫化及再生前后的结构进行了分析。结果表明,脱硫剂表面存在3种脱硫产物,HS、S形成的吸附配合物和ZnS,370℃时可直接通入空气进行连续5次再生。经过第1次再生后纳米脱硫剂结构便趋于稳定,并在后面的循环过程中表现出较稳定的脱硫活性,但与新鲜脱硫剂相比较,其脱硫活性是新鲜脱硫剂的50%左右。再生过程中主要产物为SO2气体,还有少量的硫酸盐生成,再生后样品的晶粒尺寸、形貌变化不大,但比表面积和孔容变化明显,这也是导致脱硫活性下降的主要原因。
In order to reduce the application cost of nano-ZnO desulfurizer, and to avoid its secondary pollution on environment, sulfidation and regeneration of Fe-doped nanosized ZnO desulfurizer (FZ5.0) prepared by homogeneous precipitation were studied. XRD, XPS, TEM and other characterization means were used to analyze the structure of FZ5.0 before and after sulfidation and regeneration. The results show that there exist three desulfurization products on the surface of desulfurizer, ZnS and adsorption species of HS and S could be regenerated by directly pumping air for five times at 370℃. The structure of the nanosized desulfurizer tends to be stable after the first regeneration, and shows stable desulfurization activity in the following reusing process. The desulfurization activities of the regenerated desuffurizer are about 50% of those of fresh desulfurizer. SO2 is the primary product and there is a small amount of sulfates produced in the regeneration, and particles size and appearance of regeneration samples changed little, but their surface area and pore volume change obviously, which are the main reason for the decrease of desulfurization activities.