储能科学与技术 ›› 2022, Vol. 11 ›› Issue (6): 1957-1967.doi: 10.19799/j.cnki.2095-4239.2022.0031

• 化工与储能专刊 • 上一篇    下一篇

C8H18~C11H24 混合烷烃体系相变材料的热力学性能

蒋铖一(), 钟尊睿, 吴自德, 彭浩()   

  1. 南京工业大学机械与动力工程学院,江苏 南京 211816
  • 收稿日期:2022-01-17 修回日期:2022-02-02 出版日期:2022-06-05 发布日期:2022-06-13
  • 通讯作者: 彭浩 E-mail:201961207107@njtech.edu.cn;phsight1@hotmail.com
  • 作者简介:蒋铖一(1995—),男,硕士研究生,研究方向为低温相变储能材料,E-mail:201961207107@njtech.edu.cn
  • 基金资助:
    国家自然科学基金项目(51776095)

Thermodynamic properties of C8H18-C11H24 mixed alkane system phase change materials

JIANG Chengyi(), ZHONG Zunrui, WU Zide, PENG Hao()   

  1. School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu, China
  • Received:2022-01-17 Revised:2022-02-02 Online:2022-06-05 Published:2022-06-13
  • Contact: PENG Hao E-mail:201961207107@njtech.edu.cn;phsight1@hotmail.com

摘要:

混合烷烃由于其相变温度可调,相变焓高,是性能优异的相变储能材料,但目前低温混合烷烃体系相变材料的研究较少。因此针对C8H18、C9H20、C10H22和C11H24二元混合烷烃体系开展热力学性能研究,探究混合烷烃体系相变温度、相变焓与其组成之间的影响规律,绘制了其固液相图。采用不同的热力学模型预测了二元混合烷烃熔化过程的相变温度及相变焓,并与实验结果相互验证。结果表明:C9-C10和C9-C11体系表现出共晶行为,共晶组分为88%(质量分数,余同)C9-12%C10和90%C9-10%C11,共晶温度分别为218.25 K和215.15 K。C8-C9体系具有包晶现象,C10-C11体系表现出完全互溶,它们的最小熔点分别为200.25 K和234.35 K。此外,采用UNIQUAC模型预测的熔化温度与C8-C9和C9-C10体系的实验数据更加吻合,而C9-C11和C10-C11体系则是UNIFAC模型预测的熔化温度更准确。Regular solution模型预测的四种混合烷烃体系的熔化焓更准确,平均相对偏差更小。因此,C9-C10和C9-C11共晶体系是适用于210~220 K温区的低温相变材料,为其低温储能中的应用提供了数据参考。

关键词: 相变材料, 烷烃, 热力学, 固液相图, 共晶, 包晶

Abstract:

Mixed alkane is a type of cryogenic phase change material (PCM) with superior performance, because of its adjustable phase change temperature and high phase change enthalpy. Currently, however, there are few studies on low-temperature mixed alkane systems. The thermodynamic properties of of C8H18, C9H20, C10H22 and C11H24 binary mixed alkanes systems are investigated. The solid-liquid phase diagram is drawn after studying the influence law of the phase transition temperature, phase transition enthalpy, and composition of the mixed alkane system. Different thermodynamic models predict the binary mixture's phase transition temperature and phase transition enthalpy, and the experimental results are mutually verified. The results show that C9-C10 and C9-C11 systems exhibit eutectic behavior, with the eutectic components being 88%C9 (weight percentage)-12%C10 and 90%C9-10%C11. The eutectic temperatures are 218.25 K and 215.15 K, respectively. Peritectic phenomena occur in the C8-C9 system, while isomorphous phenomena occur in the C10-C11 system. Their minimum melting points are 200.25 K and 234.35 K, respectively. Furthermore, the melting temperatures predicted by the UNIQUAC model are in better agreement with experimental data of C8-C9 and C9-C10 systems. The UNIFAC melting temperature model produces more accurate results for C9-C11 and C10-C11 systems. The Regular solution model can predict the melting enthalpy more accurately, and the average relative deviation is lower. As a result, the C9-C10 and C9-C11 eutectic systems are low-temperature phase change materials suitable for temperatures ranging from 210 K to 220 K, providing data for their use in low-temperature energy storage.

Key words: phase change materials, alkane, thermodynamics, solid-liquid phase diagrams, eutectic, peritectic

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