碱金属化合物对V2O5/AC催化剂低温脱硝的影响

研究了碱金属化合物(K₂SO₄)对活性炭(AC)担载五氧化二钒(V₂O₅)组成的V₂O₅/AC催化剂的低温脱硝活性的影响。发现在V₂O₅/AC催化剂表面负载碱金属化合物(K₂SO₄)后其脱硝活性大大降低。用等体积浸渍法制备了V₂O₅/AC催化剂和K_x-V₂/AC(x=0.5,1,2)催化剂。采用5种模型对动力学实验数据进行关联。结果显示,无论V₂O₅/AC催化剂是否负载K₂SO₄,Eley-Rideal模型均比其他模型可更好地描述SCR脱硝反应,碱金属化合物(K₂SO₄)的存在提高了反应活化能,但并不改变反应机理。

Influence of alkali metal compound on low-temperature NH3-SCR of NO over V2O5/AC catalyst

The influence of alkali metal compound(K₂SO₄)on kinetics of low-temperature SCR of NO by NH₃ over V₂O₅(vanadium pentoxide)/AC(activated carbon)catalyst was investigated.The reaction activity decreased obviously when doping the V₂O₅/AC catalyst with alkali metal compound.The V₂O₅/AC and K_x-V₂/AC(x=0.5,1,2)catalysts were prepared by the pore volume impregnation method.First,the influence of internal and external diffusions on the intrinsic kinetics experiment was eliminated. Then NH₃ SCR experiments with different NO-to-NH₃ ratios at various temperatures were carried out to test the model.Both the mechanical(i.e.Eley-Rideal model,Langmuir-Hinshelwood model,and Mars-van Krevelen model)and empirical(i.e.first-order model and power-rate law model)models were used to correlate the experimental data.The results showed that the Eley-Rideal model could well describe the SCR of NO by NH₃ over V₂O₅/AC catalyst than other models whether alkali metal compound was doped in the V₂O₅/AC catalyst or not.The presence of alkali metal compound increased the reaction activation energy,but not the reaction mechanism.