超滤膜法制备乳化柴油过程中Dean旋流效应的影响

Effect of Dean vortex efficiency on emulsification of diesel prepared by ultrafiltration membrane

根据Dean旋流原理,采用螺旋形中空纤维超滤膜制备乳化柴油,考察了螺旋形膜组件的螺距和螺径对乳化效果的影响,研究了Dean旋流效应对强化膜面剪切力、提高乳液品质、降低膜面污染等方面的作用。结果表明:螺径和螺距减小时,膜面剪切力增大,膜内的Dean旋流程度加剧,乳液液滴直径减小,但过小的螺径使液滴分散系数增加,不利于制备性能优异的乳液;同时,螺径和螺距的减小可以提高膜通量保留率,有效抑制膜面污染层的形成;与直形膜相比,螺旋形膜可显著降低乳化剂用量,其通量保留率达到直形膜的3.5倍。

Diesel emulsions were prepared by a coiled hollow fiber ultrafiltration membrane module.The effects of coiled pitch and coiled diameter on emulsion properties together with the membrane flux were investigated.It was found that the emulsion droplet size is reduced,and membrane flux is enhanced by decreasing both coiled pitch and coiled diameter.However,the emulsion cannot remain stable when coiled diameter becomes too small.Compared to a straight module,the use of coiled module can enhance diesel emulsion properties,reduce emulsion agent dosage and effectively restrain the membrane pollutant formation due to Dean vortex.