储能科学与技术 ›› 2021, Vol. 10 ›› Issue (5): 1720-1728.doi: 10.19799/j.cnki.2095-4239.2021.0319

• 物理储能十年专刊·储热 • 上一篇    下一篇

氯化盐/陶瓷定形复合相变材料的制备和热物性研究

宋文兵(), 鹿院卫(), 陈晓彤, 何聪, 樊占胜, 吴玉庭   

  1. 北京工业大学传热强化与过程节能教育部重点实验室暨传热与能源利用北京市重点实验室,北京 100124
  • 收稿日期:2021-07-05 修回日期:2021-07-15 出版日期:2021-09-05 发布日期:2021-09-08
  • 作者简介:宋文兵(1997—),男,硕士,研究方向为熔融盐复合相变材料,E-mail:18810328300@163.com|鹿院卫,教授,研究方向为可再生能源利用,E-mail:luyuanwei@bjut.edu.cn
  • 基金资助:
    国家重点研发计划项目(2017YFB0903603);国家自然科学基金项目(52076006);青海省科技计划项目(2017-GX-A3)

The preparation and thermophysical properties of chloride/ceramic-shaped stabilized composite phase-change materials

Wenbing SONG(), Yuanwei LU(), Xiaotong CHEN, Cong HE, Zhansheng FAN, Yuting WU   

  1. Key Laboratory of Enhanced Heat Transfer and Energy Conservation of Ministry of Education and Key Laboratory of Heat Transfer, Beijing University of Technology, Beijing 100124, China
  • Received:2021-07-05 Revised:2021-07-15 Online:2021-09-05 Published:2021-09-08

摘要:

为了开发一种低成本、热性能好的蓄热材料,本文选用氯化盐(CaCl2-NaCl-KCl)作为相变材料,氧化铝(α-Al2O3)为载体材料,膨胀石墨(EG)为导热增强剂,通过混合烧结法制备出CaCl2-NaCl-KCl/α-Al2O3/EG定形复合材料。基于 X 射线衍射(XRD)分析可知,氯化盐、氧化铝、EG在样品烧结过程中仅仅是物理混合,不发生化学反应;通过扫描电子显微镜(SEM)观察微观结构发现,氯化盐和氧化铝均匀混合并附着在EG的孔隙中,EG形成的孔隙有利于防止熔盐液体泄漏。通过对复合材料的热物性测量,结果表明,CaCl2-NaCl-KCl/α-Al2O3/EG复合材料在相变前(150~450 ℃)的比热容为1.35 J/(g·K),导热系数为5.03 W/(m·K);相变后(520~640 ℃)的比热容为1.43 J/(g·K),导热系数为3.18 W/(m·K)。与纯氯化盐相比,复合材料的熔点基本不变,在100~700 ℃使用范围里,复合材料的蓄热密度为902.5 kJ/kg,较纯氯化盐增加了8.3%。所制备的CaCl2-NaCl-KCl/α-Al2O3/EG复合材料,使用过程中始终保持固定形状,比热容和导热系数有较大提高,本研究为高温储热领域提供了一种可供选用的低成本且综合性能好的储热材料,为推动氯化盐在高温储热领域的实际应用提供了筛选依据。

关键词: 氯化盐, 氧化铝, 膨胀石墨, 复合材料, 热物性

Abstract:

This study aimed to develop a type of low-cost heat-storage material with good thermal performance. Chloride salt (CaCl2-NaCl-KCl) was selected as the phase-change material, alumina (α-Al2O3) was used as the matrix material, and expanded graphite (EG) was used as a thermal conductivity enhancer. A mixed sintering method prepared the CaCl2-NaCl-KCl/α-Al2O3/EG stable composite material. Based on X-ray diffraction results, chloride, alumina, and the EG physically mixed, but no chemical reaction occurred. Scanning electron microscopy was used to observe the microstructure of the EG. Chloride and alumina were evenly mixed and adhered to the pores of the EG. The pores formed by the EG helped to prevent liquid leakage. The results showed that the melting point of the composite was almost the same as that of chloride. By measuring the thermal properties of the composite material, the results showed that the specific heat capacity of the CaCl2-NaCl-KCl/α-Al2O3/EG composite material was 1.35 J/(g·K) before the phase change (150~450 ℃), and the thermal conductivity was 5.03 W/(m·K). After the phase change (520~640 ℃), the specific heat capacity was 1.43 J/(g·K), and the thermal conductivity was 5.03 W/(m·K). Compared with the chloride salt, the melting point of the composite material essentially remained unchanged. In the application range of 100~700 ℃, the composite material's heat storage per unit mass was 902.5 J/g, increasing 8.3% compared with the pure chloride salt. In the prepared CaCl2-NaCl-KCl/α-Al2O3/EG composite material, the chloride salt avoided direct contact with the container during use, thereby reducing its corrosiveness. Concurrently, the thermal performance greatly improved. This study provides an alternative low-cost and good comprehensive performance heat-storage material for high-temperature heat-storage contexts. It provides an experimental basis for promoting the practical application of chloride in high-temperature heat-storage environments.

Key words: chloride, alumina, expanded graphite, composites, thermophysical properties

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