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在传统气扫式膜蒸馏的基础上,设计了鼓气强化循环气扫式膜蒸馏过程。在循环流动的原液中鼓入低压压缩空气,在膜内腔形成气液两相流,以强化膜蒸馏传质换热;在冷侧将吹扫气循环利用。研究了原液流速以及温度、浓度、气液体积比,冷侧吹扫气流速等因素对过程性能的影响规律。结果表明,过程通量随原液温度、流速及冷侧吹扫气流速的提高而增加;原液浓度较高时,鼓气强化对膜蒸馏过程通量的促进作用明显,3.5%的NaCl溶液浓缩2.5倍以后,鼓气强化气扫式膜蒸馏过程通量比未施加鼓气强化的通量提高约20%。
On the basis of the traditional gas swept membrane distillation, a drum-swept recycle gas sweeping membrane distillation process was designed. Low-pressure compressed air is blown in the circulating liquid, and a gas-liquid two-phase flow is formed in the membrane cavity to enhance membrane mass transfer heat transfer; the cold side is used to recycle the purge gas. The influence of the flow rate of raw liquid and the temperature, concentration, gas-liquid volume ratio, flow rate of the cold-side purge gas on the process performance was studied. The results showed that the process flux increased with the increase of the temperature and flow rate of the stock solution and the flow rate of the cold-side sweep gas. When the stock solution concentration was high, the enhancement effect of the blow-enhanced gas on the membrane flux was obvious. After multiplying, the flux of air-swept enhanced membrane sweeping membrane-swept process is about 20% higher than that without booster-enhanced.