氧化镁与碳酸钙混合污垢特性的分子动力学模拟  

Molecular Dynamics Simulation Study on the Composite Fouling Characteristics of Calcium Carbonate and Nanometer Magnesia

作　　者：王景涛[1] 孙金泽 贾玉婷[1] 徐志明[1] WANG Jingtao;SUN Jinze;JIA Yuting;XU Zhiming(College of Energy and Power Engineering,Northeast Electric Power University,Jilin 132012,China)

机构地区：[1]东北电力大学能源与动力工程学院,吉林132012

出　　处：《工程热物理学报》2022年第12期3344-3351,共8页Journal of Engineering Thermophysics

基　　金：国家自然科学基金项目(No.51976028);吉林省教育厅科学研究项目(No.JJKH20210112KJ)。

摘　　要：为了研究MgO颗粒与碳酸钙(CaCO_(3))相互作用对其混合污垢形成的影响,采用分子动力学模拟方法分析了MgO颗粒与碳酸钙在水溶液体系中相互作用的影响机理。结果表明,体系中Ca^(2+)、CO_(3)^(2-)在颗粒表面的吸附对MgO颗粒运移方向造成偏移。同时,因为MgO颗粒对离子的吸附作用加速溶液中碳酸钙团簇的形成,使离子扩散系数迅速下降,其形成的碳酸钙团簇结构也更加紧密。另外,由于MgO颗粒吸附大量离子,导致体系中游离的Ca^(2+)、CO_(3)^(2-)数量减少。又因为碳酸钙团簇周围水合层的阻碍作用,相比均相成核而言,更容易在溶液中与MgO颗粒形成晶核,进一步影响换热表面所沉积的污垢量。In order to study the effect of the interaction between MgO particles and calcium carbonate(CaCO_(3))on the formation of composite fouling,the interaction mechanism between MgO particles and calcium carbonate in aqueous solution was analyzed by molecular dynamics simulation.The results show that,the adsorption of Ca^(2+)and CO_(3)^(2-)on the nanoparticles surface in the system shifts the migration direction of MgO particles.At the same time,because the adsorption of MgO particles on ions accelerates the formation of calcium carbonate clusters in the solution,the ion diffusion coefficient decreases rapidly,and the structure of calcium carbonate clusters formed is more compact.In addition,due to the adsorption of a large number of ions by MgO particles,the amount of free Ca^(2+)and CO_(3)^(2-)in the system is reduced.Because of the obstruction of hydration layer around calcium carbonate clusters,it is easier to form crystal nucleus with MgO particles in solution than homogeneous nucleation,which further affects the amount of dirt deposited on the heat exchange surface.

关 键 词：MgO颗粒 碳酸钙 混合污垢 分子动力学模拟 吸附 

分 类 号：TK124[动力工程及工程热物理—工程热物理]