柴油内蜡晶的组成与结构

Composition and Structure of Wax in Diesel

采用气相色谱分析了柴油低温析出蜡晶的化学组成,利用X射线衍射法(XRD)研究了蜡晶结构,对蜡晶形态进行了相衬显微观察,并与加入低温流动改进剂T 1804的柴油蜡晶进行对比。研究结果表明:柴油蜡晶主要由大于C16以上的正构烷烃组成,高碳数正构烷烃先析出结晶,加剂后高碳数正构烷烃含量有所减少。XRD结果显示,蜡晶结构与蜡晶中含量高的高碳数正构烷烃二十三烷结构类似,加剂后平均晶粒变小。通过对蜡晶的显微形态观察表明,加剂后蜡晶聚集体由片状变为枝状连接。

The chemical composition and structure of crystallized wax in diesel at lower temperature was analyzed using gas chromatography and X-ray diffraction（XRD）. Microscope with optical phase contrast was used to observe the shape of wax. Furthermore, the wax, being precipitated in diesel after adding cold improver T1804, was also investigated. The wax was mostly composed of alkanes, with carbon number not less than 16. Alkanes with higher carbon number crystallized more rapidly during the wax forming process. After adding the additives, the content of alkanes with higher carbon numbers in the crystallized wax was reduced. After adding the improver, the structure of wax is similar to n-tricosane and the average size of wax particles becomes smaller while the long-range order of wax increases based on XRD spectrum. The microscopic images revealed that the shapes of wax congeries changes from flake to branch when the cold improver was added.