水蒸气和α-Fe_2O_3对铈改性半焦脱除单质汞的影响研究  

Effect of water vapor and α-Fe_2O_3 on elemental mercury removal performance over cerium oxide modified semi coke

作　　者：赵可[1] 牛庆欣 王力[1] 张华伟[1] 

机构地区：[1]山东科技大学化学与环境工程学院,山东青岛266590

出　　处：《燃料化学学报》2017年第3期378-384,共7页Journal of Fuel Chemistry and Technology

基　　金：国家自然科学基金(51406107;21276146);山东省杰出青年基金(JQ201612)资助~~

摘　　要：采用浸渍法制备了铈改性半焦吸附剂(Ce/SC),在小型固定床反应器上考察了水蒸气和α-Fe_2O_3对Ce/SC脱除Hg^0性能的影响,并利用X射线衍射、H2程序升温还原、X射线光电子能谱等分析手段对其机理进行了探究。结果表明,水蒸气会明显抑制Ce/SC对单质汞的脱除效率,原因是H_2O分子在活性组分CeO_2表面发生解离,部分晶格氧转化成Ce-OH官能团,从而导致其氧化活性的降低;α-Fe_2O_3的加入对Ce/SC的脱汞性能无显著影响;当水蒸气和α-Fe_2O_3同时存在时,Ce/SC的脱汞效率虽然有所降低,但是其降低幅度明显低于水蒸气单独作用时的情况,这主要是因为水蒸气与α-Fe_2O_3作用增加了其表面化学吸附氧的含量,提高了α-Fe_2O_3的氧化活性,促进单质汞的氧化和脱除。Cerium modified semi coke adsorbent （Ce/SC） was prepared by impregnation method and a bench-scale fixed bed reactor was used to study the effect of H2O vapor and α-Fe2O3 on elemental mercury removal efficiency over Ce/SC.Characterizations of X-ray powder diffraction （XRD）, Hydrogen temperature programmed reduction （H2-TPR）, and X-ray photoelectron spectroscopy （XPS） were conducted to investigate the mechanism of elemental mercury removal.The adsorption results showed that H2O had a negative effect on the oxidation activity of the adsorbent.H2O can be dissociated on the surface of CeO2 with partial lattice oxygen transformation into Ce-OH functional groups which led to the decrease of its oxidation activity and thus resulted in the inhibitory effect of mercury removal efficiency.The addition of α-Fe2O3 had no significant effect on mercury removal over Ce/SC.The mercury removal efficiency of Ce/SC was decreased when the water vapor and α-Fe2O3 existed simultaneously.However, the decrease rate was much lower than that of water vapor conditions alone mainly due to the interaction between water vapor and α-Fe2O3 increased the content of the surface chemical adsorbed oxygen and thus the oxidation activity and elemental mercury removal performance of Fe2O3were promoted.

关 键 词：水蒸气 FE2O3 改性半焦 单质汞 

分 类 号：TQ534.9[化学工程—煤化学工程]