膜蒸馏浓缩中药提取液过程膜污染的气体反冲洗抑制

Using gas-backwashing to limit membrane fouling in the concentration of traditional Chinese medicine extracts by membrane distillation

研究了气体反冲洗对膜蒸馏浓缩中药提取液过程中膜污染的抑制作用,重点考察了反冲洗气量、反冲洗时间、反冲洗时间间隔对膜污染的抑制效果。结果表明,气体反冲洗能够明显抑制由料液中的各种污染物引起的膜污染;气体反冲洗时间越长、反冲洗气量越大、反冲洗时间间隔越小,则气体反冲洗抑制膜污染的效果越好;在反冲洗时间为2 min、反冲洗气量为2 L/min和反冲洗时间间隔为20 min的条件下,实验进行250 min时气体反冲洗能够维持膜通量在膜清水通量的80%以上。

The effect of gas-backwashing on fouling control during the concentration of extracts of traditional Chinese medicine （TCM） by direct contact membrane distillation （DCMD） has been investigated. The influence of varying the gas flow rate, gas-backwashing duration and the intermission time of gas-backwashing on fouling limitation were observed. The results revealed that gas-backwashing is an effective means of controlling membrane fouling and that longer gas-backwashing durations, higher gas flow rates and shorter intermission times give better fouling control. With a gas-backwashing duration of 2 min, gas flow rate of 2 L/min and an intermission time of gas-back- washing of 20 min for a concentration process lasting 250 min, a membrane flux of up 80% could be maintained when using tap water.