膜法供氧的传质过程研究

Study on mass transfer process of bubble-free aeration by using membranes

膜法供氧是一新兴好氧生物处理水体污染的高效供氧技术。为了更好地解释气相操作压力对供氧过程中体积传质系数的影响,对前人建立的膜法供氧的传质理论模型进行了改进,考虑了微气泡、操作压力等因素的影响;同时,建立了膜供氧装置,考察了不同气相操作压力时的供氧效果,尤其是气液二相操作压力对模型中体积传质系数的影响。结果表明,膜供氧过程的传质机理随气相操作压力的变化而不同,总体积传质系数随气相操作压力的提高呈先缓慢增高而后急剧上升最后急剧下降的三阶段变化趋势。

Bubble-free aeration by using membranes is a novel and high efficient oxygen supply technology for water treatment. An improved mass transfer model of the process was established, which can better explain the influence of gas pressure on mass transfer coefficient. The factors such as micro bubbles and gas pressure were considered in the novel model. The experiment apparatus of aeration by using membranes were set up to investigate the effect of gas pressure on oxygen supply and mass transfer coefficient. The results show that the mechanism of mass transfer varies with gas pressure change, that is, the coefficient of oxygen mass transfer increases gradually, and then dramatically, finally decreases sharply as gas pressure increases.