气态甲基碘去除特性实验研究

Experimental Research on Performance of Gaseous Methyl Iodide Removal

以安全壳过滤排放系统对甲基碘的去除性能为背景,分别以去离子水和碱性硫代硫酸钠溶液为吸收剂,对不同吸收剂温度和浓度条件下的甲基碘去除过程进行实验研究,并在此基础上分析物理传质和化学反应两种机制对甲基碘气体去除过程的影响。结果表明:室温条件下,碱性硫代硫酸钠溶液对甲基碘气体的去除作用主要以物理传质过程为主,化学反应速率较慢是限制甲基碘气体去除效率的主导因素;随着温度的增加,化学反应在甲基碘气体去除过程中的作用不断加强。当化学反应速率增加至某一值附近时,继续强化化学反应过程对甲基碘气体去除效率不再具有明显影响,吸收过程进入化学反应不敏感区域,物理传质速率成为限制甲基碘气体去除过程的主要因素。这时需通过增加气液接触面积等方法强化物理传质过程,方能进一步提升对甲基碘气体的去除效果。

Under the circumstance of gaseous methyl iodide removal process in containment venting system, taking the deionized water and alkalescent sodium thiosulphate as absorber, the experimental researches on the performance of gaseous methyl iodide removal were carried out at different solution temperatures and concentrations. And the effects of two types of mechanisms, namely mass transfer and chemical reaction, on gaseous methyl iodide removal process were analyzed based on the experimental results. The research results show that at room temperature, the mass transfer mechanism plays a dominant role in gaseous methyl iodide removal process through the absorption of alkalescent sodium thiosulphate solution. Thus, the slow chemical reaction rate is the major factor that limits gaseous methyl iodide removal efficiency. With temperature increasing, the effect of chemical reaction is constantly enhanced in the methyl iodide removal orocess. However. will get into an insensitive region when the reaction rate reaches to a certain point and the continuously enhancing chemical reaction rate will not greatly influence the removal efficiency. At that point, mass transfer performance becomes the major factor that limits gaseous methyl iodide removal process. The efficiency of gaseous methyl iodide removal can be further improved by necessary means of enhancing mass transfer process through increasing contact surface and so on.