将金属套管式微通道用于油包水(W/O)乳液的制备,系统考察了连续相中大豆油和正己烷的体积比、表面活性剂质量分数、套管环隙尺寸和微孔孔径等对乳滴粒径的影响。得到的较优制备工艺条件为:大豆油和正己烷体积比8∶10、表面活性剂Span 80的质量分数1%、微孔孔径5μm、套管环隙尺寸250μm,可制备出平均粒径约为13μm且分散性良好的W/O乳液。与高速均质机和Y型微通道的比较发现,其所得乳液分散性和稳定性优于后两者,可望满足实际工业应用需求的高通量(至少可达1 L/min)。此外,实验考察了微通道结构参数对乳化压降的影响,结果表明乳化压降随微孔孔径、套管环隙尺寸的减小而增大。
A water in oil(W/O) emulsion has been successfully prepared in a novel high-throughput microporous tube-in-tube microchannel(MTMC) device.The effects of varying the volume ratio of soybean oil to n-hexane in the continuous phase,the surfactant mass fraction,micropore size and annular channel width on the droplet size were investigated in detail.The optimum conditions were obtained as follows: a soybean oil to n-hexane volume ratio of 8∶10,a mass fraction of Span 80 of 1.0%,a micropore size of 5 μm,and an annular channel width of 250 μm.Under these conditions,emulsion droplets with an average size of 13 μm and good monodispersity could be obtained.Emulsification in MTMC offers advantages over typical homogenizers and a Y-junction microchannel,and a high throughput of 1 L/min was obtained.In addition,the effects of structural parameters on the emulsification pressure drop were investigated.The results showed that the emulsification pressure drop increased with decreasing micropore size and annular channel width.