三元硫酸熔盐的制备及其热稳定性能  

Preparation and thermal stability of a ternary sulfate molten salt

作　　者：朱教群[1] 陈维[1] 周卫兵[1] 李儒光[1] 张弘光[1] 

机构地区：[1]武汉理工大学材料科学与工程学院,湖北武汉430070

出　　处：《储能科学与技术》2016年第4期498-502,共5页Energy Storage Science and Technology

基　　金：国家科技支撑计划项目(2012BAA05B03)

摘　　要：以硫酸钠、硫酸钾和硫酸镁为原料,采用在硫酸钠-硫酸钾二元共晶盐中加入硫酸镁的方法制备三元硫酸熔盐。应用TG-DSC联用分析仪、热常数分析仪、X射线衍射仪以及热循环法对复合熔盐的熔点、相变潜热、热导率、比热容、分解点以及热稳定性进行表征。结果表明：所制备的三元硫酸熔盐熔点分布在667.5~669.7℃之间,较二元熔盐熔点降低了160℃左右,硫酸镁含量为30%（质量分数）的三元硫酸熔盐相变潜热值最大为94.3 J/g,比热容最大为1.13 J/（g·K）（720℃≤T≤800℃）,导热系数为0.41 W/（m·K）,分解温度为1070℃,经50次热循环后,相变潜热值降低约4.34%,熔点和物相保持基本恒定,具有良好的热稳定性。该研究为硫酸盐作为高温传热蓄热介质提供了依据。Using Na_2SO_4, K_2SO_4 and MgSO_4 as raw materials, a new type of ternary sulfate molten salt was formulated by adding different amounts of Mg SO4 to the binary eutectic salt of Na_2SO_4-K_2SO_4. The salt was characterized for its melting temperature, latent heat, thermal conductivity, specific heat, decomposition temperature and thermal stability using thermogravimetric analysis（TG）, differential scanning calorimetry（DSC）, Thermal constants analyzer, X-ray diffraction and cyclic thermal testing. Experimental results showed that the ternary sulfate molten salt had a melting point ranging between 667.5 ℃ and 669.7 ℃, ~160 ℃ lower than that of the binary sulfate molten salt. The ternary salt containing 30% MgSO_4 by mass was found to give the highest latent heat of 94.3 J·g^-1; the corresponding specific heat capacity was 1.13 J·（g·K）^ -1 between 720 ℃ to 800 ℃, and thermal conductivity was 0.41 W·（m·K） ^-1. The decomposition temperature was found to be 1070 ℃. Cyclic testing of the salt showed a slight decrease in the latent heat by 4.34% after 50 cycles, however, little changes occurred to the melting temperature and phase composition, indicating that the ternary salt with 30%（weight ratio） MgSO_4 had a good thermal stability.

关 键 词：熔融盐 熔点 分解温度 热稳定性 

分 类 号：TK512[动力工程及工程热物理—热能工程]