沥青质分子界面行为的耗散粒子动力学  

Dissipative Particle Dynamics of Asphaltene Molecular Behaviors at Interface

作　　者：吴九柱 付威 胡艳娇[1] 王子璇 常广涛 张慧先 WU Jiuzhu;FU Wei;HU Yanjiao;WANG Zixuan;CHANG Guangtao;ZHANG Huixian(Airport College, Civil Aviation University of China, Tianjin 300300, China;Natural Gas Business Division, PetroChina Tarim Oilfield Company, Tarim 841000, China;Huabei Oil & Gas Branch Company, SINOPEC, Zhengzhou 450000, China)

机构地区：[1]中国民航大学机场学院,天津300300 [2]中国石油塔里木油田分公司,天然气事业部,新疆塔里木841000 [3]中国石化华北油气分公司,河南郑州450000

出　　处：《石油学报（石油加工）》2021年第5期1106-1113,共8页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：中央高校基金项目(3122019108);中国民航大学科研启动基金项目(2020KQYQD41)资助。

摘　　要：运用耗散粒子动力学(DPD)方法模拟了“孤岛型”沥青质分子和其纳米聚集体在油-水界面的取向性、聚集行为,分析了富氧支链对沥青质分子取向性的影响。结果表明:存在油-水界面时,沥青质分子从油、水相中脱离,吸附在油-水界面处,稠芳环核与油-水界面平行,烷烃支链伸入油相;随着沥青质浓度升高,空间位阻作用使沥青质分子彼此分离,稠芳环核与界面存在夹角,直至部分沥青质被“挤出”界面;在π-π相互作用下,被“挤出”界面的稠芳环核与吸附在油-水界面的稠芳环核平行堆叠,距离约为0.5 nm,烷烃支链将稠芳环核包围;沥青质纳米聚集体由于被烷烃支链包裹,极易脱离油-水界面,溶于油相;富氧支链亲水性强,伸入水相,使稠芳环核与油-水界面产生夹角,甚至垂直;富氧支链会改变沥青质分子的取向性。The dissipative particle dynamics(DPD)method was used to investigate orientation,aggregation behavior of“island”type asphaltene molecules and nano-aggregates at the oil-water interface,and the influence of oxygen-rich branch chains on the orientation of asphaltene molecules.The results show that the asphaltene molecules leave oil or water phase and are adsorbed at the oil-water interface,where the fused aromatic ring core is parallel to the oil-water interface,while the alkane branch extends into the oil phase.As the concentration increases,the asphalt molecules separate from each other because of the steric hindrance,and an angle exists between the fused aromatic ring core and the interface,until some of part of the asphalt is“squeezed out”from the interface.Due to theπ-πstacking,the fused aromatic ring core of asphaltene molecules“squeezed out”from the interface is parallel to that adsorbed on the oil-water interface,with the distance of 0.5 nm,and the alkyl chains surround the fused aromatic ring core.The nanoaggregates are wrapped by alkane branches which is strongly oil-wet and are easily soluble in the oil phase.The oxygen-enriched branches are highly hydrophilic and extend into the water phase.There is an angle between the fused aromatic ring core and oil-water interface,which could be vertical.The oxygen-enriched branches change the orientation of asphalt molecules.

关 键 词：沥青质分子 聚集行为 耗散粒子动力学 Π-Π相互作用 

分 类 号：TE622.1[石油与天然气工程—油气加工工程]