沥青岩中界面活性沥青质分子结构及其在矿物表面吸附特征

Molecular structure of interfacially active asphaltene in asphalt rock and its adsorption characteristics on mineral surface

重质油固体系(如油砂、沥青岩、油页岩、重质油、油泥等)中因油-水-固三相复杂作用,导致分离困难。本文以印尼沥青岩重质油为例,针对重质组分中界面活性最强的界面活性沥青质的结构及其在矿物质表面吸附特性问题进行研究。通过凝胶渗透色谱、红外光谱仪、XPS等对界面活性沥青质的结构进行分析,提出其初步结构。以SiO_(2)为矿物固体模型,在甲苯溶剂环境中,采用QCM-D和AFM研究界面活性沥青质在固体表面的吸附特征,发现该类沥青质分子在SiO_(2)表面的吸附与普通沥青质分子存在较大差异,呈现多层吸附特征,符合Freundlich吸附模型。吸附膜存在较多高分散性团聚体,黏弹性较大,易于形成具有三维结构的强机械性界面膜。该结构和界面吸附特性可为揭示其在油水乳液稳定过程中的机理提供有利基础。

Separation is difficult due to the complex interaction of oil-water-solid three phases in heavy oil solids(such as oil sands,bituminous rocks,oil shale,heavy oil,oil sludge,etc.).This article takes Indonesian bituminous heavy oil as an example to study the structure of the interfacially active asphaltene which has the strongest interfacial activity among the heavy components and its adsorption characteristics on the surface of minerals.The structure of interfacially active asphaltene was analyzed by gel permeation chromatography,infrared spectrometer,XPS,etc.,and its preliminary structure was proposed.Taking SiO_(2) as the mineral solid model,using QCM-D and AFM to study the adsorption characteristics of interfacially active asphaltenes on the solid surface in a toluene solvent environment,it is found that the adsorption of this subfraction of asphaltene molecules on the SiO_(2) surface is larger than that of ordinary asphaltene molecules.The difference shows the characteristics of multilayer adsorption,which is in line with the Freundlich viscoelasticity,and is easy to form a strong mechanical interface film with three-dimensional structure.The structure and interface adsorption characteristics can provide a favorable basis for revealing its mechanism in the oil-water emulsion stabilization process.