EVA类降凝剂对生物柴油低温流动性的作用机理

Mechanism of EVA pour point depressant in biodiesel

通过预筛选试验确定了乙烯-醋酸乙烯酯(EVA)类降凝剂对生物柴油低温流动性的改善作用。采用差热分析(DSC)、低温X光衍射仪(XRD)、偏光显微镜等表征方法研究了EVA类降凝剂对生物柴油的降凝机理。实验结果表明,降凝剂加入生物柴油后没有减少蜡晶的析出量,而是通过与脂肪酸甲酯之间的共晶作用,改变了蜡晶的生长习性和聚集方式。蜡晶的外观呈现类球状,表现出优异的分散性,蜡晶之间不易交联,进而降低了生物柴油的冷滤点和冷凝点。

The effect of ethylene-vinyl acetate （EVA） pour point depressant was determined on biodiesel by pre-screening. DSC, low temperature XRD and polarizing optical microscope were used to study the mechanism of ethylene-vinyl acetate pour point depressant （PPD） on soybean biodiesel. The results show that： PPD does not reduce the amount of wax crystals in biodiesel. Eutectic effect occurs between PPD and fatty acid methyl ester. PPD changes the growth habits and gathering way of the wax crystals. The wax crystals appear almost spherical, disperse better, not easy to crosslink between wax crystals and reduce the cold filter plugging point （CFPP） and solidification point （SP） of biodiesel.