SCR脱硝过程中SO<sub>2</sub>催化氧化的原位红外研究

SCR脱硝过程中SO₂催化氧化的原位红外研究

摘要: 采用工业用V₂O₅-WO₃/TiO₂催化剂,基于傅里叶原位红外光谱(FT-IR)技术考察SO₂的氧化过程及烟气组分对SO₂氧化行为的影响;结果表明,SO₂在催化剂表面氧化主要是首先吸附在催化剂表面V₂O₅活性位上,占据其O原子,以SO^2-₃形式存在,后与催化剂表面V⁵⁺-OH发生反应,生成金属硫酸盐(VOSO₄)中间产物,O₂重新氧化催化氧化过程中由于被SO₂夺取O原子而被还原的V₂O₅物种,使V⁴⁺转化为V⁵⁺,促进金属硫酸盐(VOSO₄)向SO₃转化;SO₂与NO、NH₃的竞争吸附阻碍SO₂在V₂O₅活性点位上的氧化;在SCR中,NO的脱除与SO₂的氧化是相互抑制的关系。

Abstract: This work briefly reveals the process of catalytic oxidation of SO₂ and the influences of NH₃, NO and O₂ on the oxidation behavior based on FT-IR.It suggests that the process of oxidation of SO₂: the absorption of SO₂ on V₂O₅ sites occupying its O atom in the form of SO^2-₃; reaction between absorbed SO₂ and O atom in V⁵⁺-OH to form an VOSO₄-like structure;reoxidation of V⁴⁺ to V⁵⁺ by O₂,promoting the transformation from VOSO₄-like intermediate to SO₃ and V₂O₅. NH₃ and NO competitively absorb with SO₂,suppressing its oxidation behavior. The removal of NOx and the oxidation of SO₂ is the relationship of mutual inhibition.