The influence of some commonly used pour point depressants (PPD) mixed with acetic acid ester solvent on biodiesel were investigated. The mixed sample which had the most obvious effect was selected, and its action mechanism on cold flow property of biodiesel was studied using DSC and polarizing optical microscope. The results show that the pour point depressant 10-330 which is mixed with butyl acetate in 8 ∶ 1 (mass ratio) has the best pour point reducing effect on biodiesel. As the pour point depressant mixed with acetic acid ester solvent is added in biodiesel, when the temperature falls, the quantity of crystal decreases sharply, the growth of the crystals changes, thus simultaneously makes the enthalpy change of solid-liquid reduce, and the homogeneousness and stabilization of the system increases, so the cold flow property of biodiesel improves.%考察了几种常用的柴油降凝剂与乙酸酯类有机溶剂的复配对生物柴油的影响.将复配效果较好的样品筛选出来,并采用差热分析(DSC)、偏光显微镜研究其对生物柴油低温流动性的影响机理.实验结果表明:当聚甲基丙烯酸酯类降凝剂10-330与乙酸丁酯以质量比8∶1复配时,对生物柴油的降凝效果最好；降凝剂与乙酸酯复配后添加到生物柴油中,使体系在冷凝过程中析出的晶体量大幅减少,改变晶体的成长方式,使晶体的尺寸较小,从而改变晶体的形态与分散状态,使得体系的固液相变能减小,分散体系更加稳定,进而提高生物柴油的低温流动性能.
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