微纳气泡对气溶胶池洗去除特性影响研究

Influence of Micro-nano Bubbles on Aerosol Pool Scrubbing Performance

  • 摘要: 反应堆发生严重事故时,微纳米级放射性气溶胶颗粒随高压气体排入抑压水池,在池洗机理作用下滞留在水池中,从而达到防止放射性外泄的目的。已有研究表明,气溶胶池洗效率曲线呈U型分布,当气溶胶粒径在0.1~1 μm范围内时,其池洗效率最低。为了提高该粒径范围内的气溶胶池洗效率,本研究借鉴微纳气泡在环境治理方面能够高效去除环境杂质的优势,开展了微纳气泡水中气溶胶池洗效率实验。通过设置对照实验,研究了微纳气泡水的基本特性与去离子水的不同,并将含气溶胶气体分别注入去离子水和微纳气泡水中,对比分析了两种池洗液体中的气溶胶池洗效率,从而探究了微纳气泡对气溶胶池洗去除特性的影响规律。实验结果表明,微纳气泡能够降低池洗液体与固体表面的接触角,提高池洗液体的负zeta电位,使气溶胶更容易穿透气液界面进入到液相中;同时,常规气泡在微纳气泡水中的尺寸更小,单位时间内脱离喷嘴的常规气泡数量增加,使微纳气泡水中常规气泡具有更大的比表面积,且能够在液相中滞留更长时间。这些变化使得微纳气泡水中0.25~1 μm粒径范围内气溶胶颗粒的池洗效率显著提高。本研究可以为气溶胶池洗系统设计优化提供实验基础和理论依据。

     

    Abstract: During a nuclear severe accident, micro-nano radioactive aerosol particles will be generated and discharged into the suppression pool with high pressure gas, and then remain in the pool water under the mechanism of pool scrubbing, so as to achieve the purpose of preventing radioactive leakage. Previous studies show that the aerosol pool scrubbing efficiency curve presents a U-shaped distribution, and when the aerosol particle size is within 0.1-1 μm, the pool scrubbing efficiency is the lowest. In order to improve the pool scrubbing efficiency of aerosols in the above particle size range, the advantages of micro-nano bubbles in environmental treatment which can efficiently remove environmental impurities were learned in this study, and an experiment on the pool scrubbing efficiency of aerosol in micro-nano bubble water was carried out. By setting a control experiment, the difference between the basic characteristics of micro-nano bubble water and deionized water was first studied, and then aerosol-containing gas was injected into the deionized water and micro-nano bubble water respectively, and the removal efficiency of aerosol pool scrubbing in the two pool washing liquids was compared and analyzed, so as to explore the influence of micro-nano bubbles on the removal characteristics of aerosol pool scrubbing. The experimental results show that the micro-nano bubbles can reduce the contact angle between the pool scrubbing liquid and the solid surface, increase the negative zeta potential of the pool scrubbing liquid, and make the aerosol more easily penetrate the gas-liquid interface into the liquid phase. At the same time, the size of conventional bubbles in micro-nano bubble water is smaller, and the number of conventional bubbles leaving the nozzle per unit time increases, so that the conventional bubbles in micro-nano bubble water have a larger specific surface area and can stay in the liquid phase for a longer time. These changes make the removal efficiency of aerosol particles in the particle size range of 0.25-1 μm in micro-nano bubble water significantly improved. This study can provide experimental basis and theoretical basis for the design and optimization of aerosol pool scrubbing system.

     

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