燃煤烟气条件下锰铈基催化剂对邻二甲苯催化氧化

MnCe based catalyst for o-xylene catalytic oxidation from coal-combustion flue gas

燃煤烟气中有机污染物的排放逐渐引起重视。锰铈(MnCe)基催化剂被认为是一种低温高效、低成本的可应用于燃煤烟气污染物脱除的催化剂。本文通过浸渍法制备了MnCe基催化剂,通过物理化学表征和烟气模拟台架实验,研究了MnCe基催化剂配比、反应工况、烟气复杂组分(H2O、SO2、NH3、NO)以及典型污染物脱除过程(Hg0和NO催化转化)对催化脱除烟气中邻二甲苯行为的影响和规律。实验结果表明,Mn和Ce摩尔比为6∶4时催化剂脱除邻二甲苯效率良好。反应空速和MnCe负载量在低温下对催化脱除效率影响显著。烟气中H2O、SO2、NH3、NO等组分对催化产生抑制作用,但抑制程度与作用机理具有显著差异。MnCe基催化剂对烟气SCR脱硝与Hg0催化氧化皆具有较高效率,且受烟气中邻二甲苯影响较小;但受SCR气氛与Hg0抑制,邻二甲苯催化脱除反应效率明显降低。

The environment pollution from coal-fired combustion emission has aroused increasingly attention.MnCe based catalyst was regarded as a promising alternative catalyst for flue gas pollutants removal due to its high catalytic efficiency under low temperature and low cost.In this work,MnCe based catalysts were prepared via impregnation method for the removal of o-xylene from simulated flue gas.The effects of MnCe amount,reaction condition,the complex components in flue gas(H2O,SO2,NH3,NO) and typical pollutants on the catalytic removal of o-xylene have been investigated.The results indicated that reaction velocity and the catalyst loading amount had affected the o-xylene removal,especially at low reaction temperatures.H2O,SO2,NH3,NO in the flue gas showed inhibit effect on o-xylene removal in different degrees following different mechanisms.The mole ratio of Mn to Ce of 6∶4 showed satisfactory catalytic efficiency for o-xylene.The MnCe based catalyst exhibited good catalytic efficiencies towards NO removal and Hg0 oxidation in the flue gas,which were not obviously affected by the existence of oxylene.However,the existence of SCR atmosphere and Hg0 had significantly inhibited the o-xylene removal.