镁基三元氯化物熔盐储热过程性能变化机理分析  

MECHANISM ANALYSIS OF PERFORMANCE CHANGE OF TERNARY CHLORIDE MOLTEN SALT STORAGE PROCESS

作　　者：魏小兰[1] 尹月 丁静[2] 宋明[1] 刘波[1] 王维龙[2] 

机构地区：[1]华南理工大学化学与化工学院,广州510640 [2]中山大学工学院,广州510275

出　　处：《太阳能学报》2018年第1期37-43,共7页Acta Energiae Solaris Sinica

基　　金：NSFC-柴达木盐湖化工科学研究联合基金(U1507121);国家自然科学基金重点项目(51436009)

摘　　要：为了解镁基三元NaCl-MgCl2-CaCl2氯化物熔盐储热过程性能变化本质,采用质量法监测熔盐在不同高温下储热过程的质量损失;采用DSC热分析和激光闪射热扩散系数测定法,监测熔盐在700℃下分别储热8、32、40 h后的热物性变化;采用滴定和原子吸收分析法测定熔盐储热前后的组成变化;采用XRD和SEM分析熔盐劣化产物性质。质量损失监测结果发现,在敞口容器中,熔盐在500℃储热时出现质量损失,随着温度提高质量损失程度明显增大;在有盖容器中,质量损失程度大幅度降低。DSC热分析结果表明,在敞口容器中,熔盐700℃下储热8、32、40 h后,熔盐熔点明显上升且相变潜热下降。组成测定、XRD与SEM分析结果显示,熔盐在敞口容7器中进行储热,其性能劣化现象是NaCl蒸发和MgCl2水解共同作用的结果,在储热8 h后MgCl2几乎全部水解为MgO和Mg（OH）2,形成粒径约1μm的颗粒均匀地分散在熔盐中形成固/液流体。激光闪射分析表明,含有MgO的固/液流体其热扩散系数明显上升。In order to understand heat storage processes performance change of nature about NaCl-MgCl2-CaCl2 , using the method of quality to monitor quality loss of molten salt under different high temperature heat storage process ; using DSC thermal analysis and laser method, monitoring the thermophysical properties change of molten salt that working 8 h, 32 h, 40 h under 700 ℃, respectively; Using the method of coordination titration and atomic absorption to mensurate the composition change of molten salt after heating storage ; Analyzing the degradation properties of molten salt product by XRD and SEM. The loss of quality monitoring results found in open vessels, molten salt emerge quality loss at 500 ℃ , the extent of quality loss obviously increases with temperature increase ; In a covered container, the degree of quality loss greatly reduce. DSC thermal analysis results showed that in the open container, after heating storage 8, 32 and 40 h, the melting point of molten salt significantly increased and the latent heat of phase change significantly decreased. The composition determination, XRD and SEM analysis showed that the heat storage molten salt working in open vessels, the performance deterioration determined of NaCl evaporation and hydrolysis of MgCI2 , MgCl2 almostly hydrolysis MgO and Mg（OH）2 after 8 h heat storage , generate MgO particles about 1 μm , solid/ liquid fluid. Laser analysis significantly increased showed that the presence of MgO uniform dispersed in the molten salt and form a let thermal diffusion coefficient of molten salt

关 键 词：储热 热扩散系数 熔点 组分变化 氯化物熔盐 

分 类 号：TQ050.91[化学工程]