重质油沥青质缔合行为及介尺度行为的电学响应研究

The heavy oil is a colloidal system, and the aspahtene aggregation plays an important role in the heavy oil processing, which is the bottleneck of the refinery of heavy oil. This project is focused on the measurement of asphaltene aggregating and the mesoscopic behaviors of asphaltenes in heavy oil through dielectric relaxation spectroscopy (DRS). Since the asphaltene is the fraction having strong electrical response in heavy oil, the electrical response can be capable of relating the asphaltene aggregating behavior and the mesoscopic size of asphaltene aggregate in heavy oil. Based on the study of the relationship between the structural characteristics, polarity, aggregation behavior or the mesoscopic size, and electrical response, the aggregating strength origins and the mechanism of action can be gained. Then the internal factors can be gained. In order to study the external factors of temperature and pressure, the aggregating behavior and the mesoscopic behavior of asphaltenes can be studied on-line, by the help of an autoclave with inner electrodes. In order to study the relationship between the dielectric permittivity, mesoscopic size of asphaltene aggregate, or the macroscopically reactivity behavior, an autoclave with inner electrodes has been made to order to study the dielectric relaxation and conductivity of the heavy oil sample online. The new colloidal stability measurement method without using precipitant, can be constructed by the understanding the relationship between the electric response and the colloidal stability of heavy oil. This study is helpful to the cognition of asphaltene stabilization mechanism, and to the enhancements of heavy oil production, transportation and processing.

重质油是以沥青质为核心的分散体系，沥青质缔合和聚沉是重质油加工的瓶颈问题。本项目针对重质油沥青质电学响应较强的特点，利用介电弛豫谱表征，建立沥青质缔合行为和介尺度行为的电学响应表征方法。研究沥青质化学性质（结构特征、极性）与缔合行为和介尺度行为的关系，认识沥青质缔合行为和介尺度行为的内在影响因素，探究沥青质偶极相互左右在沥青质缔合中的作用机制。利用介电弛豫谱、借助内置电极高温高压反应釜，对重质油沥青质在高温、高压下的缔合行为和介尺度行为进行在线表征，认识沥青质粒度变化及温度、压力等外在因素的影响。建立不需使用沉淀剂、适用于高温高压的新型重质油胶体稳定性电学表征方法。并通过对重质油反应样品的组分组成和组分性质研究，认识重质油反应过程组分化学性质、缔合行为和介尺度行为、电学响应的变化规律。研究成果有助于深入认识重质油沥青质稳定机理，指导重油加工工艺的选择和优化，指导重油生产、储运、加工等过程。

重质油是以沥青质为核心的分散体系，沥青质缔合和聚沉是重质油加工的瓶颈问题。本项目针对重质油沥青质电学响应较强的特点，利用介电弛豫谱表征，建立了沥青质缔合行为和介尺度行为的电学响应表征方法。对稠油沥青质溶液、不同反应时间样品的介电弛豫谱进行了研究，认识沥青质化学性质（结构特征、极性）与缔合行为和介尺度行为的关系，认识沥青质缔合行为和介尺度行为的内在影响因素，探究沥青质偶极相互左右在沥青质缔合中的作用机制。利用X射线吸收精细结构谱（XANES）对重质油沥青质的含硫结构进行了表征。为考察重质组分含硫官能团形态和含量，利用同步辐射技术采集沥青质、胶质硫的XANES谱图，采用高阶导数谱图进行定性分析，采用非线性高斯拟合进行定量分析，结果表明：沥青质、胶质含硫官能团类型相同，主要为噻吩，其次为亚砜、砜和少量硫酸酯。在加氢反应过程中，随着反应程度的加深，沥青质或胶质中噻吩硫、亚砜硫、砜硫的绝对含量均逐渐减小，而硫酸酯的含量逐渐增加，说明还原态硫和中间态硫活性较高，容易脱除，相反氧化态硫活性较低，难以脱除。利用介电弛豫谱、借助内置电极高温高压反应釜，对重质油沥青质在高温、高压下的缔合行为和介尺度行为进行在线表征,建立不需使用沉淀剂、适用于高温高压的新型重质油胶体稳定性电学表征方法。并通过对重质油反应样品的组分组成和组分性质研究，认识重质油反应过程组分化学性质、缔合行为和介尺度行为、电学响应的变化规律。研究成果有助于深入认识重质油沥青质稳定机理，指导重油加工工艺的选择和优化，指导重油生产、储运、加工等过程。