UV/H2O2液相氧化净化烟气中NO的实验研究

采用UV/H₂O₂液相氧化技术净化气体中的NO,通过正交实验和单因素实验,研究了H₂O₂浓度、温度、初始pH值、NO浓度、光照条件、O₂含量和气体流量等因素对NO去除率的影响.结果表明,UV/H₂O₂液相氧化体系对NO有良好的净化效果,可以获得80%左右的NO去除率, 温度、H₂O₂浓度和初始pH值对NO去除率具有不同程度的影响,温度和H₂O₂浓度对NO去除率影响较大.单因素实验结果表明, 当H₂O₂浓度为0.2 mol/L、初始pH值为6～7时NO去除率较高;溶液中H₂O₂浓度过高或过低、溶液过酸或过碱均会抑制·OH的产生而不利于NO的去除;净化NO的最佳反应温度为40 ℃,低于一般湿法脱硝温度(50 ℃);NO的去除率随紫外光辐射强度和O₂含量的增加而升高;同时,NO的去除也受气液传质面积和气液传质系数的控制.

Experimental Research of Purification NO-Containing Gas by Aqueous Oxidation with UV/H2O2

The influence of some experimental factors on removal efficiency of nitric oxide (NO) under the condition of liquid-phase oxidation with UV/H2O2, such as H2O2 concentration, solution temperature, initial pH, NO concentration, illumination condition, O2 content and gas flow rate, were investigated by employing orthogonal experiments and single factor experiments. The results showed that NO could be efficiently removed by the aqueous oxidation technology with UV/H2O2 system, and the highest NO removal rate was about 80%. Moreover, H2O2 concentration, temperature and initial pH had varying degree effects on purifying NO-containing gas, whereas NO removal rate were more affected by H2O2 concentration and temperature. The single factor experimental results showed that high NO removal rate could be obtained when H2O2 concentration was 0.2 mol/L and the initial pH was 6-7. H2O2 concentration and initial pH should be maintained at an appropriate level or the production of *OH could be restricted, which would result in lower NO removal rate. The optimum operation temperature was 40 degrees C, which is lower than common operating temperature (50 degrees) for the wet scrubber. Enlarging the illumination strength and O2 content could improve the NO removal rate. Furthermore, the NO removal rate was also controlled by the area and coefficient of gas-liquid mass transfer.