AVS型柴油降凝剂的性能

Performance of AVS Diesel Fuel Pour Point Depressant

冯立娟 张志庆 王 芳 王 涛 杨 姗

FENG Li-Juan ZHANG Zhi-Qing WANG Fang WANG Tao YANG Shan

通过自由基聚合合成了四种不同烷基链长的丙烯酸烷基酯-醋酸乙烯酯-苯乙烯三元共聚物，测定了共聚物对柴油的降凝降滤效果，用气相色谱仪测定了柴油中正构烷烃的含量和分布，用高级流变仪和光学显微镜研究了柴油加降凝剂和未加降凝剂的流变行为和结晶行为。结果表明：烷基链长与柴油中正构烷烃的平均碳数接近的降凝剂降凝效果最好，可使凝点降低12℃，而使柴油中蜡晶变的更分散更均匀的降凝剂降滤效果最好，可使冷滤点降低4℃；蜡晶的大小、形状和聚集状态直接影响柴油的冷滤点，而三维网状结构的形成对柴油的凝点起决定性的作用，好的柴油降凝剂应该既不利于三维网状结构的形成，又不使蜡晶变的太大或聚集成太大的簇状结构。

AVS Diesel Fuel pour point depressant, n-alkyl acrylate-vinyl acetate-styrene terpolymers with different alkyl chain length，named as AVS-12, AVS-14, AVS-16 and AVS-18 according to alkyl chain length, were synthesized by radical polymerization, and the effect of the systems on the solidifying point (SP) and cold filter plugging point (CFPP) of diesel fuel was determined. The content and the carbon number distribution of n-alkanes in diesel fuel were analyzed by gas chromatograph; the rheological behavior and crystallization behavior of diesel fuel treated with and without additives were studied using an advanced rheometer and an optical microscope. The results demonstrated that the terpolymer whose alkyl chain length was close to the average carbon number of n-alkanes in diesel fuel had the best effect on reducing the SP and could reduce the SP by 12℃. The terpolymer which made the wax crystals more dispersed and evenly had the best effect on reducing the CFPP could reduce the CFPP by 4℃. The size, shape and aggregation of wax crystals directly affected the CFPP of diesel fuel, while the formation of three-dimensional network played a decisive role on the SP, thus a good diesel pour point depressant should be adverse to the formation of three-dimensional network and detrimental to the formation of too large wax crystals or wax crystals tending to form large clusters.