溴掺杂钒钛催化剂SCR反应动力学研究

摘要

针对适用于焦化烟气的溴掺杂钒钛催化剂,为进一步探索其脱硝机理及动力学规律,研究采用浸渍法制备V/Br-Ti催化剂,从瞬态动力学和稳态动力学的角度对催化剂进行反应动力学研究.结果表明,在250℃时4V5Br-Ti催化剂的脱硝效率达到98%;在V/Br-Ti催化剂上进行的SCR反应机制是吸附态的NH3与气态或弱吸附态的NO发生反应;O2是以气态氧、表面吸附氧和晶格氧三种形态参与SCR反应的.在实验条件下,V/Br-Ti催化剂的NH3、O2、NO反应级数分别为0、0.5、1级.4V5Br-Ti催化剂SCR表观反应活化能为35.4 kJ.mol-1,低于目前商用的钒钛基脱硝催化剂,表明该催化剂具有较高的反应活性,具有一定的实际工业应用潜力.%V/Br-Ti catalysts were prepared via an impregnation method and de-NOx mechanism and kinetics of coking flue gas were studied with Br-doped V2O5/TiO2. The reaction kinetics was investigated by transient and steady-state experiments. The results indicate that the denitration efficiency of 4V5Br-Ti is 98% at 250℃. The SCR reaction mechanism of V/Br-Ti is: the adsorbed NH3 reacts with gaseous or weakly surface adsorbed NO, and O2 participates in the SCR reaction in the state of gaseous, surface adsorbed or lattice oxygen. The reaction orders of NH3, O2 and NO are 0, 0.5 and 1, respectively. The apparent activation energy of 4V5Br-Ti catalyst is 35.4 kJ.mol-1, which is lower than the apparent activation energy of the current commercial vanadium titanium based catalysts. The results indicate that the V/Br-Ti catalyst has high reaction activity and industrial application potential.