海水换热器常用于沿海能源和化工领域的海水直流冷却系统和循环冷却系统。海水在热交换的过程中容易产生析晶结垢，造成换热效率下降和管路堵塞，这些污垢的组成及结垢机理是目前研究热点之一。本研究搭建一套海水结垢的可视化实验装置，对海水在换热过程中形成的析晶污垢进行了物相分析和动力学研究。通过X射线衍射(X-ray Diffraction，XRD)、扫描电镜(Scanning Electron Microscope，SEM)和X射线能谱(Energy Dispersive X-Ray，EDX)分析海水换热器析晶污垢的元素组成和晶体结构，结果显示污垢的元素组成和晶体结构与水合氢氧化镁铝(Mg6Al2(OH)18·4.5H2O)十分相似。基于Kern-Seaton模型，建立适用于海水析晶污垢的动力学模型，并根据实验结果对结垢过程的动力学参数进行拟合。结果表明：在不锈钢表面海水析晶结垢的表观活化能为1.54×104 J/mol，在实验工况下海水析晶结垢是一种扩散控制过程。

The seawater heat exchangers are generally used in direct current system or recycle system of electric power and petrochemical industry,while the seawater frequently causes crystallization fouling in the heat exchanges.The paper built a visual system to investigate the composition and kinetic mechanism of seawater crystallization fouling.The crystallization fouling composition and crystal structure were analyzed by SEM,EDX and XRD.The results show that the composition and crystal structure of seawater fouling are both Mg6Al2(OH)184.5H2O.Based on the Kern-Seaton model,a new crystallization-fouling kinetic model was proposed in the paper.The experimental data of different conditions were fit to the model,and the kinetic parameters were obtained.The apparent activation energy of seawater crystallization-fouling is 1.54×104J/mol,which is much close to the diffusion free energy of fouling-ions in seawater.It means that the forming process of seawater fouling is controlled by diffusion.

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上海市教育委员会和上海市教育发展基金会“晨光计划”资助(16CG55）；上海海洋大学博士科研启动基金（A2-0203-17-100317）；上海海洋大学科技发展专项基金（A2-0203-17-100207）