Abstract:

Polyethersulfone ultrafiltration（UF）membrane with an average pore size of 25 nm was used for preparing W/O diesel emulsion. With the help of UF membrane，emulsification was accomplished by dispersing  deionized water into 0^#diesel oil using Tween-20 and Span-80 as surfactant in each phase. Nanoparticles formed at the permeate side of the membrane are swept away by the recirculating organic phase inside the membrane module when the aqueous phase is forced to pass through the membrane. The prepared diesel emulsion demonstrated 200%—250% longer stability and 50%—65% less emulsifier consumption compared with those prepared with traditional methods，such as high speed homogenization.  In addition，the impact of operating parameters，such as emulsifier dosage，flow rate and organic phase pressure，on emulsion properties was also discussed. Results illustrated that emulsified diesel with nanoparticle sizes of as small as 30—65 nm and a distribution coefficient a of 0.12—0.3 could be obtained at a transmembrane pressure of 0.02 MPa and a cross flow rate of 2.0—5.0 m/s with the mass content of emulsifier higher than 0.5%.

摘要：

采用平均孔径为25 nm的聚醚砜超滤（UF）膜，以去离子水为分散相，以0^#柴油为连续相，分别以Tween-20和Span-80为分散相及连续相的乳化剂，采用膜乳化法制备W/O型乳化柴油。UF膜乳化法制备的乳液比传统乳化方法稳定时间提高2～2.5倍，而相同条件下乳化剂用量减少了50%～65%。此外，考察了UF膜法制备乳化柴油过程中的各工艺参数对乳液液滴大小、分布及稳定性的影响规律，结果表明：当乳化剂质量分数高于0.5%，连续相流速在2.0～5.0 m/s范围内，跨膜压差为0.02 MPa时，乳液分散系数a达到0.12～0.3，液滴尺寸为30～65 nm。