Experimental Research on the Vapor Pressures of CaCl2–H2O and MgCl2–H2O as Working Fluids of Absorption Heat Transformers at High Temperature
Experimental Research on the Vapor Pressures of CaCl2–H2O and MgCl2–H2O as Working Fluids of Absorption Heat Transformers at High Temperature
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DOI：
10.1021/acs.jced.1c00397
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发表时间：
2021-11
影响因子：
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通讯作者：
Jielin Luo;Ruirui Zheng;Shao-zhi Zhang;Guangming Chen;Qin Wang
中科院分区：
文献类型：
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作者：
Jielin Luo;Ruirui Zheng;Shao-zhi Zhang;Guangming Chen;Qin Wang
氯化钙溶液(CaCl2-H2O)和氯化镁溶液(MgCl2-H2O)具有腐蚀性低的特点，被认为是潜在的吸收式换热器(AHTS)工质。工作流体的蒸汽压是吸收系统中应用的一个重要性质。然而，目前的实验数据大多局限于温度和浓度范围，适用于温度要求低于323.15 K的除湿系统，因此需要更准确的蒸汽压数据。本文用静态法测定了CaCl2和MgCl2水溶液在323.15~373.15 K温度范围内的平衡蒸汽压，其中CaCl2的质量分数为0.10~0.5%，MgCl2的质量分数为0.05%~0.3%。实验数据与常用的e-NRTL模型相关联，CaCl2-H2O和MgCl2-H2O的平均绝对相对偏差(AARD)分别为2.27和1.61%。然后用修正的Antoine方程对数据进行关联，AARD分别降至0.51和0.50%。并对典型循环中CaCl2-H2O和MgCl2-H2O的热力学性能进行了估算。结果表明，与常用的LiBrH2O相比，CaCl2-H2O和MgCl2-H2O具有更低的循环倍数，性能差异系数小于2%，说明了它们的应用前景。
Aqueous calcium chloride solution (CaCl2–H2O) and magnesium chloride solution (MgCl2–H2O) are regarded as potential working fluids of absorption heat transformers (AHTs) because of their characteristics of low corrosiveness. The vapor pressure of a working fluid is an important property for applications in absorption systems. However, current experimental data are mostly limited to temperature and concentration ranges, which are suitable for dehumidification systems, whose temperature requirement is always lower than 323.15 K. Thus, more accurate data of vapor pressures are anticipated. In this paper, the equilibrium vapor pressures of aqueous CaCl2and MgCl2solution were measured with the static method in the temperature range from 323.15 to 373.15 K. The mass fraction of CaCl2varied from 0.1 to 0.5, and the mass fraction of MgCl2varied from 0.05 to 0.3. The measured data were correlated with a common-used e–NRTL model, whose average absolute relative deviations (AARD) for CaCl2–H2O and MgCl2–H2O were 2.27 and 1.61%, respectively. The data were then correlated with a modified Antoine equation, and the AARD were reduced to 0.51 and 0.50%, respectively. The thermodynamic performance of CaCl2–H2O and MgCl2–H2O for the AHT were also estimated for a typical cycle. The results demonstrate that compared with the common-used LiBr–H2O, both CaCl2–H2O and MgCl2–H2O deliver lower circulation ratios with a coefficient of performance difference less than 2%, so their application prospects are illustrated.