沥青质分子聚集行为研究进展

沥青质的聚集与其相行为、流动性、结焦、沉积等密切相关,是影响重油加工的关键。沥青质分子结构的高芳香性、高杂原子含量等特点,使其存在多个易发生分子间相互作用的活性位点,是沥青质发生聚集的主要原因。描述沥青质聚集行为的模型主要有Yen-Mullins模型、超分子组装模型、类线性聚合模型以及溶解度模型等,本文对这些模型进行了详细的介绍,分析了各种模型的特点。文中指出Yen-Mullins模型通过沥青质分子、纳米聚集体、团簇描述了沥青质聚集过程;超分子组装模型基于超分子化学,认为沥青质聚集是多种相互作用累积形成的超分子结构;类线性聚合模型和溶解度模型都是对沥青质聚集行为进行简化,主要用来预测沥青质的分子量和溶解行为。沥青质的分子结构是产生各种相互作用及聚集行为的基础,而现有的分离和表征主要是基于沥青质团聚体,因此高效分离和精确表征得到沥青质单分子结构是研究沥青质分子间相互作用及聚集机理的关键。

Research progress on aggregation behavior of asphaltene

The aggregation of asphaltene is closely related to its phase behavior, fluidity, coking and precipition in heavy oil processing. The high aromaticity and high heteroatom content in molecular structure, which make they have many active sites are the main reason for asphaltene aggregation. Various models describing asphaltene aggregation behavior, including Yen-Mullins model, supramolecular assembly model, linear-like aggregation model and solubility model, were introduced in detail, and the characteristics of various models were analyzed. The Yen-Mullins model showed the dominant molecular and colloidal structures containing asphaltene nano-aggregates and clusters. The supramolecular assembly model was based on supramolecular chemistry, and it was considered that asphaltene aggregation formed the supramolecular structure with the accumulation of various interactions. Both the linear polymerization model and the solubility model were simplified model that mainly used to predict the molecular weight and dissolution behavior of asphaltene. The molecular structure of asphaltene was the basis of various interactions and aggregation behaviors, and the current separation and characterization were mainly based on asphaltene aggregates. Therefore, efficient separation and accurate characterization on asphaltene to get monomolecular structure was the key point of research on the interaction and aggregation mechanism of asphaltene.