十八胺在压水堆凝汽器母管内壁碳钢表面的吸附机制研究  

Adsorption Mechanism of Octadecylamine on Inner Surface of Condenser Main Pipe Carbon Steel of Pressurized Water Reactor

作　　者：刘灿帅 林根仙[1] 孙云[1] 方军 宋利君[1] 刘斌[1] LIU Canshuai;LIN Genxian;SUN Yun;FANG Jun;SONG Lijun;LIU Bin(Suzhou Nuclear Power Research Institute,Suzhou 215004,China)

机构地区：[1]苏州热工研究院有限公司,江苏苏州215004

出　　处：《原子能科学技术》2022年第9期1932-1943,共12页Atomic Energy Science and Technology

摘　　要：为研究十八胺在压水堆凝汽器母管内壁碳钢表面的吸附机制,本文主要利用分子动力学软件模拟计算十八胺在碳钢表面的吸附过程,使用无定形单元模块建立十八胺分子在金属界面的吸附模型,采用吸附模块逐层计算吸附结构,采用分子动力学模块获得稳定吸附构型。结果表明,十八胺在碳钢表面发生多层物理吸附,吸附层数随十八胺浓度的增加而增加。对吸附前后的稳定构型进行能量计算,获得了吸附自由能,发现十八胺分子的第一层吸附能主要由范德华力提供,其他多层吸附能主要由静电力提供;随着吸附层数的增加,十八胺分子自发吸附的趋势逐渐减弱。Carbon steel pipe is widely used in condenser of PWR nuclear power unit.Its corrosion during outage can give rise to prolonged downtime.Furthermore,the corrosion products migration to steam generator accumulates sludge formation.It can not only cause water chemistry environmental degradation,reduce heat pipe heat transfer efficiency,but also increase the corrosion risk of steam generator.In order to study the adsorption mechanism of octadecylamine(ODA)on carbon steel surface of inner wall of main tube of PWR condenser,molecular dynamics simulation software was used to simulate the adsorption process of ODA on carbon steel surface.From the perspective of thermodynamics,calculating the adsorption free energy of film-forming amine molecules on carbon steel surface by thermodynamic data and determining the type of force field constituting the adsorption free energy are effective methods to study the adsorption of organic molecules.In the first step,the adsorption model of ODA on metal interface was established by using amorphous cell module.According to the strongest X-ray diffraction peak,the Fe(110)plane of preferred orientation of metal Fe was selected to construct the interface adsorption model.In the second step,sorption module was used to calculate the layout,and ODA and H_(2)O adsorption simulation was realized.The COMPASSⅡforce field,atom based summation method and NVT ensemble were used to filling 20 ODA molecules and 100 H_(2)O molecules into the super cell vacuum layer ranging from 5%to 90%.The distribution model of ODA and H_(2)O molecules in the super cell structure was preliminarily obtained.In the third step,the Forcite module was used to calculate the stable adsorption configuration,and the Gibbs free energy before and after the adsorption was calculated to obtain the adsorption free energy.In the fourth step,the adsorption procedures according to the above steps were repeated layer by layer until the fifth layer,and the adsorption free energy was also calculated layer by layer.The main conclusions

关 键 词：十八胺 碳钢 吸附 自由能 

分 类 号：TL364.5[核科学技术—核技术及应用]