对直接接触式膜蒸馏浓缩中药提取液进行了研究,分析了浓缩过程跨膜通量下降的原因,并考察了药液温度和流速对跨膜通量的影响。结果表明:由提取液中固体颗粒等污染物造成的膜污染以及膜表面处水蒸汽压下降是浓缩过程跨膜通量下降的主要原因。在浓缩倍数较低(1.0～4.0)的范围内，通量下降主要是由膜污染造成的;在浓缩倍数较高（4.0～16.0）的范围内，膜表面处水蒸汽下降也显示其影响。药液温度从46℃升高到60℃，通量从13.88kg/(m²·h)升高到30.82kg/(m²·h)。药液流速从0.074m/s升高到0.130m/s，通量从24.14kg/(m²·h)升高到31.22kg/(m²·h)。

A study of the concentration of a Traditional Chinese Medicine extract by direct
contact membrane distillation has been carried out in order to determine the re
ason why the transmembrane water flux declined during the concentration process. The effects of varying the extraction temperature and the flow velocity in the membrane module were investigated. It was found that during the concentration process, the flux reduction was mainly caused by membrane fouling in the earlier stages of lower extract concentration (i.e. when the concentration was increased by a factor of 4.0). In the latter stages of extract concentration (i.e. when the concentration was from increased from 40 to 160 times its initial value), the reduction in water vapor pressure also contributed significantly to the decline in flux. It was also found that when the extraction temperature and velocity were increased from 46℃ to 60℃ and from 0.074m/s to 0.130m/s respectively, the transmembrane water flux increased from 13.88kg/(m²·h) to
30.82kg/(m²·h) and from 24.14kg/(m²·h) to 31.22kg/(m²·h) respectively. 