煤基航煤基础油中实际胶质的结构表征与分析

Structural characterization and analysis of existent gum in coal-based aviation kerosene base oil

以煤基航煤基础油为原料,提取出了实际胶质,采用元素分析、凝胶渗透色谱、X射线光电子能谱分析、红外光谱等手段对胶质的组成结构进行表征,系统研究了胶质中元素的赋存形态和相对含量,探讨了促进胶质生成与聚集的影响因素。结果表明,胶质分子整体趋于酸性,芳环和其他不饱和官能团较多。杂原子主要为O和N,含量超过20%,O的赋存形态有羟基或醚键(C—O)、羰基(C=O)、羧基(COO—)和吸附氧,N的赋存形态有吡啶型氮、吡咯型氮、氮氧化合物和胺类。羧酸、杂环氮化合物参与胶质形成的反应,羧基、羟基与吡咯型氮、吡啶型氮结合形成氢键,促进胶质的生成和聚集;此外,烯烃基团亦是促进胶质生成的重要因素。相比于石油类胶质和煤焦油类胶质,煤基航煤基础油胶质中的不饱和结构所占比例更大;在油品的深加工过程中,此类胶质容易通过加氢脱氧、脱氮和烯烃加氢饱和等方式脱除。

Using coal-based aviation kerosene base oil as raw material, the existent gum was extracted.The composition and structure of the gum were characterized by elemental analysis, GPC, XPS and FTIR.The occurrence forms and relative contents of elements in the gum was systematically studied. The factors promoting the formation and aggregation of the gum were discussed. The results show that the gum molecules tend to be acidic as a whole, with more aromatic rings and other unsaturated functional groups.The heteroatoms are mainly O and N, and the content is more than 20%. The existing forms of O are hydroxyl or ether bond(C—O), carbonyl(C=O), carboxyl(COO—) and adsorbed oxygen. The existing forms of N are pyridine nitrogen, pyrrole nitrogen, nitrogen oxides and amines. Carboxylic acids and heterocyclic nitrogen compounds participate in the reaction of forming gum. The carboxyl and hydroxyl groups combine with pyrrole nitrogen and pyridine nitrogen to form hydrogen bonds, which promote the formation and aggregation of the gum. In addition, olefin groups are also important factors in promoting the formation of the gum. Compared with petroleum gum and coal tar gum, the proportion of unsaturated structures in coal-based aviation kerosene base oil colloids is larger. In the deep processing of fuel oils products, such gums are easily removed by hydrodeoxygenation, hydrodenitrogenation, and olefin hydrogenation and saturation.