NaCl-MgCl2-CaCl2相图计算方法研究

为满足规模化太阳能热发电中对传热蓄热的要求,针对储能材料开展探究。以熔融盐热物性及经济性作为筛选条件,选定来源广泛、价格低廉、工作温度范围宽、黏度低、相变潜热大的NaCl、MgCl₂和CaCl₂三元熔盐体系开展深入研究。应用修正的准化学溶液模型,在子二元系基础上推导计算三元混合熔盐NaCl-MgCl₂-CaCl₂相图。结果表明,该熔盐混合物共晶点温度为412.45 ℃,NaCl、MgCl₂和CaCl₂的摩尔分数分别为50.99%、22.78%和26.23%,与已有文献数据相比,误差在3%以内,验证了方法的准确性,为构建熔盐氯化物相图数据库奠定了部分基础。

RESEARCH ON CALCULATION METHODS OF NaCl-MgCl2-CaCl2 PHASE DIAGRAM

Energy storage materials have been widely studied and used to meet heat transfer requirements and storage in large-scale solar thermal power generation. Taking the thermal physical properties and economy of molten salt as screening conditions, ternary molten salt systems of NaCl, MgCl₂, and CaCl₂ with wide sources, low price, wide operating temperature range, low viscosity, and large latent heat of phase transition were selected for in-depth study. Based on the sub-binary system., the modified quasi-chemical solution model was used to calculate the phase diagram of ternary mixed molten salt NaCl-MgCl₂-CaCl₂. The calculated results show that the eutectic point temperature of the molten salt mixture is 412.45 ℃, and the molar fractions of NaCl, MgCl₂, and CaCl₂ is 50.99%, 22.78%, and 26.23%, respectively. Compared with the existing literature data, the error is less than 3%, which verifies the accuracy of the method. It lays a partial foundation for the construction of a phase diagram database of molten salt chloride.