蜡晶对油水界面稳定性的耗散粒子动力学研究  

Research of Stability of Paraffin Crystallization on Oil-water Interface via Dissipative Particle Dynamics

作　　者：李期斌[1] 曹金琛 刘朝[1] LI Qibin;CAO Jinchen;LIU Chao(Key Laboratory of Low Grade Energy Utilization Technology and System,Ministry of Education,School of Energy and Power Engineering,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学低品位能源利用技术及系统教育部重点实验室,能源与动力工程学院,重庆400044

出　　处：《工程热物理学报》2023年第6期1465-1472,共8页Journal of Engineering Thermophysics

基　　金：国家自然科学基金资助项目(No.51876015)。

摘　　要：随着油田的不断开发,石蜡结晶和油水乳化作用为含蜡原油的开采、运输和储存带来巨大挑战。本文采用耗散粒子动力学方法研究了石蜡相变结晶对油水界面稳定性的影响。首先,计算了石蜡分子的序参量,揭示了水分子和油分子均会促进石蜡分子形成有序的固态晶体结构。其次,发现随着蜡含量的增加,油-水界面的表面张力逐步提高,石蜡分子会提高油-水界面的稳定性。最后,得到油-水界、蜡-水界面,蜡-油界面表面张力随温度的变化关系(298~348 K)。结果表明,当温度低于308 K,油-水界面和蜡水界面都能维持其界面的稳定性。对于蜡-油界面,当温度高于308 K时,达到石蜡的析蜡温度,石蜡晶体逐步熔化,蜡-油之间的界面张力急剧减小,蜡油界面逐渐消失。With the continuous development of oil fields,paraffin crystallization and oil-water emulsification pose great challenges to the production,transportation and storage of waxy crude oil.The effect of paraffin phase transformation crystallization on the stability of oil-water interface was studied by using dissipative particle dynamics(DPD)method.Firstly,the order parameters of paraffin were calculated,and it was revealed that both water and oil molecules could promote the formation of ordered solid crystal structure of paraffin.Secondly,it is found that with the increase of wax content,the surface tension of oil-water interface gradually increases,and paraffin molecules can improve the stability of oil-water interface.Finally,the relationship of surface tension of oil-water interface,wax-water interface and wax-oil interface with temperature was obtained(298~348 K).The results show that the oil-water interface and wax-water interface can maintain the stability when the temperature is lower than 308 K.For the wax-oil interface,when the temperature is higher than 308 K,the temperature reaches the wax evolution temperature of paraffin,the paraffin crystal gradually melts,the interfacial tension between wax-oil decreases sharply,and the wax-oil interface gradually disappears.

关 键 词：油-水界面 表面张力 序参量 蜡结晶 耗散粒子动力学 

分 类 号：O552[理学—热学与物质分子运动论]