柴油低温流动改进剂的复配及降凝效果的评价

柴油低温流动改进剂的复配使用是提高柴油在低温下流动性的重要手段之一。考察了复配型柴油低温流动改进剂的3个复配单元以不同配比复配后对0号柴油低温性能的影响,采用冷滤点来评价改进剂的降凝效果,并用差示扫描量热法(DSC)进一步分析蜡晶在低温下的结晶过程。结果表明:聚富马酸烷基酯-醋酸乙烯酯共聚物(PFVA)与聚乙烯-乙酸乙烯酯(EVA)、二(氢化牛脂基)邻苯二甲酸酰胺(Tab)复配产生一定的协同作用,当总加剂量为500μg/g,PFVA,EVA,Tab质量分数分别为46%,46%,8%时,冷滤点降低了19℃,析蜡高峰值温度降低,蜡晶相变热ΔH的绝对值降低,有效地延缓了蜡晶的析出,从而提高了柴油的低温流动性。

EFFECTS OF COMBINATION OF COLD FLOW IMPROVERS ON DIESEL SOLIDIFICATION POINT DEPRESSION

Combination of solidification point depressants is one of the effective means to improve low temperature properties of diesel fuel. In this paper, three kinds of solidification point depressants and their combinations with different ratios were used to investigate the effect on the reduction of solidification point of 0# diesel fuel from the refinery of Jilin Petrochemical Company. Cold Filter Plugging Point (CFPP) and differential scanning calorimeter (DSC) were used to evaluate the solidification point reduction effect and clarify the mechanism of wax crystallization at low temperature. The results indicate that there is a better synergistic effect in the combination use of di-n-alkyl fumarate-vinyl acetate copolymer (PFVA) and polyethylene-vinyl acetate (EVA) and paraffin crystal dispersant 2-(hydrogenated tallow) phthalic acid amide (Tab). The CFPP can be reduced by 19 ℃ at the sum dose of 500 ug/g with the ratio of PFVA 46%: EVA 46%: Tab 8%. Both of the peak temperature for wax crystal precipitation and the absolute value of wax crystal phase change heat ΔH is reduced. The combinations of solidification point depressants can delay the wax crystal precipitation, thus improves the low temperature fluidity of diesel fuel.