强电离放电降解甲醛的研究

Study on Formaldehyde Degradation by OH· Using Strong Ionization Discharge

[目的]研究强电离放电降解甲醛的效果。[方法]采用强电离放电的方法产生羟基自由基（OH·），进行不外加吸收剂和催化剂的甲醛脱除试验，分别研究甲醛气体初始浓度、气体流量、停留时间、外加电压等因素对甲醛降解效率η的影响。[结果]随着HCHO初始浓度的增加，HCHO分子与活性粒子碰撞、反应的机率减小，当HCHO初始浓度大于500mg／m^3，甲醛净化效率田下降幅度增大。降解过程中随着停留时间的增加，去除效率η增大，0．6s以后田增加不明显，停留时间以0．4～0．5s为宜。降解过程中，气体流量Q对甲醛的净化效率η也有较大的影响，随着Q的增加，η下降明显。等离子体反应器外加电压U的变化对降解效率有显著影响，可在等离子体反应器能承受的电压3．6kV内，通过大幅度提高外加电压能够提高降解效率η。降解过程中，没有任何有机气体产生，甲醛的降解效率可达85％以上。[结论]强电离放电降解甲醛可有效去除HCHO，且反应过程不需外加吸收剂和催化剂，无二次污染。生成产物是CO2和H2O。

[ Objective ] The research aimed to study the effects of formaldehyde degradation using strong ionization discharge. [ Method ] A majority of gas molecules in the air such as O2 and H2O were ionized and made into OH · of high concentration using strong ionization discharge method to carry out formaldehyde removal experiment without catalyst and absorbent. And some factors such as initial concentration,gas flow ,residence time ,applied voltage which affected the formaldehyde removal efficiency were studied. [ Result]The resalts showed that as the initial concentration of formaldehyde increased,the probabilities of collision and reaction between formaldehyde and active molecules decreased. When it was higher than 500 mg/m^3 ,the decrease range of formaldehyde removal efficiency（77） increased. During the process of formaldehyde degradation, as the residence time increased,ηincreased. After 0.6 s,tbe increase of r/became unconspicuous,and the suitable residence time was 0.4 -0.5 s. At the same time gas flow（Q） had great impacts onη,Q increased ,η decreased significantly. Applied voltage（U） of plasma reactor had obvious impacts on η,when U increased obviously during 3.6 kV ,η could be raised. During the process of formaldehyde degradation,there was no other organic gas generated,and ηcould reached higher than 85%. [ Conclusion] Under the condition of normal temperature, non-catalyst and non-absorbent, formaldehyde was directly oxidized into CO2 and H2O in plasma reactor. It had realized resource utilization without second pollution.