生物柴油低温流动性能研究

LOW TEMPERATURE CHARACTERISTICS OF BIODIESELS

采用气相色谱法测定了菜籽油生物柴油、大豆油生物柴油和花生油生物柴油中脂肪酸甲酯的分布和含量,采用燃料低温性能测定仪和旋转黏度计考察了生物柴油的低温流动性能及流变特性。结果表明:生物柴油的低温流动性能与其饱和脂肪酸甲酯的分布和含量密切相关。花生油生物柴油的饱和脂肪酸甲酯含量比菜籽油生物柴油的高10.5%,其冷滤点和凝点比菜籽油生物柴油的高8℃,0℃时花生油生物柴油黏度比菜籽油生物柴油高57.42 mPa·s。生物柴油在低温下失去流动性的主要原因是析出晶体,并连接成网状结构,将低熔点的柴油吸附于其中。

The fatty acid methyl ester compositions of rape biodiesel, soybean biodiesel and peanut biodiesel were determined by gas chromatography. Cold flow properties and rheologieal performances of the biodiesels were studied by using a multifunctional low temperature instrument and a rotatory viscometer. The cause of losing fluidity was investigated by a differential scanning calorimeter and a polarized microscope. The results indicated that the low-temperature fluidity of the biodiesels is related to the compositions of the saturated fatty acid methyl ester. The content of the saturated fatty acid methyl ester of the peanut biodiesel was 10.5 % higher than that of the rapeseed bioidesel. Cold filter plugging point and freezing point of the peanut biodiesel were 8℃ higher than those of the rapeseed biodiesel. The peanut biodiesel showed viscosity 57.42 mPa · s higher than the rapeseed biodiesel at 0℃. The primary reason for the biodiesels to lose fluidity at low temperatures can be ascribed to the production of a spongy waxy crystal matrix which adsorbs the low melting point biodiesel.