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等离子体协助选择性催化还原(PF-SCR)可以促进富氧环境下NOx的有效脱除。为研究实际尾气中含有的水蒸气和CO2对PF-SCR脱除NOx系统的影响,以C2H4作为还原剂,Ag/γ-Al2O3为催化剂,考察了3种(N2/O2/NOx/C2H4,N2/O2/NOx/C2H4/H2O(气)和N2/O2/NOx/C2H4/H2O(气)/CO2)配气条件下PF-SCR脱除NOx效果的变化。试验结果表明,较低水蒸气含量(φ(H2O)=1%)对PF-SCR还原NOx具有明显的抑制作用,其原因除了Ag/γ-Al2O3的抗湿性能较差外,水蒸气对等离子体反应器中C2H4和NO氧化的抑制以及由此导致的活性中间产物生成抑制也是一个重要因素。另一方面,水蒸气的存在也抑制了PF-SCR过程中副产物CO的大量生成,这可能是由于PF-SCR对C2H4的氧化减弱以及等离子体氧化生成的中间产物减少造成的。有水蒸气存在时,体系中的CO对PF-SCR还原NO影响不大。
Plasma-assisted selective catalytic reduction (PF-SCR) can promote the efficient removal of NOx in an oxygen-rich environment. In order to study the influence of water vapor and CO2 contained in the tail gas on the removal of NOx from PF-SCR, three kinds of catalysts (N2 / O2 / NOx / C2H4, N2 / O2 / NOx / C2H4 / H2O (gas) and N2 / O2 / NOx / C2H4 / H2O (gas) / CO2). The experimental results show that the lower water vapor content (φ (H2O) = 1%) has a significant inhibition effect on the reduction of NOx by PF-SCR. The reason for this is that besides the poor moisture resistance of Ag / γ-Al2O3, Inhibition of C2H4 and NO oxidation in bulk reactors and the resulting inhibition of active intermediate production are also an important factor. On the other hand, the presence of water vapor also suppresses the mass production of byproduct CO in the PF-SCR process, which may be attributed to the weakened oxidation of C2H4 by PF-SCR and the reduction of intermediate products generated by plasma oxidation. In the presence of water vapor, CO in the system has little effect on the reduction of NO by PF-SCR.