利用固定床反应器在模拟烟气条件下研究了凹凸棒石(PG)负载CuO催化剂(CuO/PG)对气态Hg0的脱除.考察了CuO负载量、反应温度、烟气成分、SO2浓度以及空速等对CuO/PG脱除Hg0的影响,并利用逐级化学提取和程序升温脱附实验分析了CuO/PG上吸附Hg的形态.结果表明,CuO/PG对Hg0具有较高的脱除能力,明显高于载体PG,且随CuO负载量的增加而增强(1%—8%);在150—250℃温度范围内,温度升高,CuO/PG对Hg0的脱除能力降低;HCl对CuO/PG脱除Hg0具有显著的促进作用,O2具有促进作用,H2O和SO2具有抑制作用,NO的作用不明显;在6000—15000 h-1空速范围内,空速降低,CuO/PG表现出了更好的脱除Hg0的能力.逐级化学提取和程序升温脱附实验结果证实,CuO/PG对Hg0的脱除是吸附和催化氧化的共同作用,Hg0被氧化为Hg2+的化合物并吸附在CuO/PG上.
Removal of vapor-phase Hg0 over a palygorskite(PG) supported CuO catalyst(CuO/PG) was studied in a fixed-bed reactor in simulated flue gas.The influence of CuO loading,temperature,flue gas components,SO2 concentration and space velocity on Hg0 removal was investigated,and the Hg adsorbed over CuO/PG was also characterized.It was found that CuO/PG catalyst had a much higher Hg0 removal capability than that of PG,which increased with CuO loading(1%—8%).CuO/PG showed a high Hg0 removal capability in the temperature range of150—250 ℃ and space velocity range of 6000—15000 h-1,and a lower temperature or space velocity was benificial for Hg0 removal.HCl and O2 had a positive effect on Hg0 removal over CuO/PG while SO2 and H2O showed an inhibition effect.Sequential chemical extraction andtemperature programmed desorption experiments confirmed that Hg0 removal over CuO/PG was the combined effect of oxidation and adsorption,in which the catalytic oxidation activity of CuO played a crucial role.