微通道内气-液传质研究

Mass transfer in gas-liquid flow in microchannels

以CO2-H2O为模型体系,实验考察了当量直径为667 μm的单通道和16个并行通道内的气-液传质行为.实验发现,液体表观速度增加,单通道内液侧体积传质系数明显提高;同一液体表观速度下,液侧体积传质系数随气体表观速度增加而增加;在实验数据基础上关联了液侧体积传质系数与气-液两相流参数间的关系.微通道内的液侧体积传质系数较常规尺度气-液接触设备至少高1～2个数量级.并讨论了并行微通道内气-液两相流分配特性对整体传质性能的影响,表明合理设计气、液流动分布结构,可保证微通道内优异的传质特性.

Experimental results on physical absorption of CO2 into water in micro-contactors with a single and 16 parallel microchannels having hydraulic diameter of 667 μm were presented respectively. It was shown that the liquid side volumetric mass transfer coefficients increased dramatically with the increase of superficial liquid and gas velocities in single microchannel, Then correlations were proposed to depict the relationship between liquid side volumetric mass transfer coefficients and operational parameters, Compared with the conventional gas-liquid contactors, micro-contactors can provide at least one or two orders of magnitude higher liquid side volumetric mass transfer coefficients, Finally, the effect of two-phase flow distribution in parallel microchannels on the overall mass transfer performance was discussed, which revealed that specially designed inlet flow distribution areas of gas and liquid could guarantee high mass transfer rates in the subsequent microchannels.