以KMnO4、NaClO2为氧化剂进行模拟烟气吸收试验,探究单一碱液吸收剂、Na-K协同吸收剂对去除烟气中NOx的影响,引入微量SO2-3离子对吸收效率进一步优化。结果发现,KOH碱液性能明显高于NaOH,30min内KOH平均吸收率高达99.4%,NaOH的平均吸收率仅86.9%,这是K+离子半径更大,更易解离OH-所致。以0.1mol/L的KMnO4作为氧化剂、双组份吸收液(n(Na)∶n(K)=1∶2,n为物质的量浓度)效率更高更稳定,30min仍可达86%,是双金属离子的电荷传递效应,使气相反应物向液相传递时气膜迅速破裂,减少了气液两相的扩散时间所导致,并通过DFT模拟计算充分证实了这一点。通过在吸收液中引入微量SO2-3离子,平均吸收率提高了3%,证明SO2-3离子进一步促进了硝酸盐物种的吸收转化。

The flue gas absorption test was simulated using KMnO4 and NaClO2 as oxidants, and the effects of single alkaline absorptionsolutions and Na-K synergistic absorption solutions on the removal of NOx from flue gas were investigated. Trace amounts of SO2-3 ions wereintroduced during the process to further optimize the absorption efficiency. The results indicate that the performance of KOH alkaline solution is significantly higher than that of NaOH. The average absorption rate of KOH within 30 minutes of absorption is as high as 99.4%,while NaOH only achieves an average absorption rate of 86.9%. This difference can be attributed to the larger ionic radius of K+ ions,which facilitates the dissociation of OH- ions. When using 0.1 mol/ L KMnO4 as the oxidant and a two-component absorption solution (n(Na) ∶ n(K)= 1 ∶ 2), the efficiency is higher and more stable, reaching 86% even after 30 minutes. It is due to the charge transfereffect of bimetallic ions, which results in the rapid rupture of the gas film when gas-phase reactants transfer to the liquid phase, reducingthe diffusion time between the gas and liquid phases. This phenomenon has been thoroughly confirmed through density functional theory(DFT) simulation calculations. The average absorption rate is increased by 3% by introducing trace amounts of SO2-3 ions into the absorption solution, demonstrating that SO2-3 ions further promote the absorption and conversion of nitrate species.

0 引言

1 材料和方法

   1.1 试验装置和材料

   1.2 色谱条件的确定

   1.3 试验条件

2 结果和讨论

   2.1 去离子水、NaOH和KOH吸收剂对未预氧化NOx的吸收性能

   2.2 预氧化剂的选择

   2.3 不同种类吸收液对NOx吸收性能的影响

   2.4 吸收液浓度对NOx吸收性能的影响

   2.5 添加SO2对脱硝效率的影响

   2.6 添加Na2SO3对脱硝效率的影响

3 离子色谱测定吸收液中阴离子浓度

   3.1 碱液中离子性质的变化

   3.2 添加SO2碱液中离子性质的变化

   3.3 添加Na2SO3碱液中离子性质的变化

   3.4 吸收液脱硝反应机理探究及反应热计算

4 结论