Performance comparison of different working pairs on a liquid desiccant dehumidification system with vacuum regeneration

doi:10.11949/0438-1157.20230646

Abstract

Abstract:

An experimental and simulation study on a liquid desiccant dehumidification system with vacuum regeneration is carried out in this paper. The experiment compares the system performance of LiCl solution and mixed solution of CaBr₂∶CaCl₂=1∶1. It is found that the outlet moisture content and COP of the two solutions are relatively close. When the driving temperature is 62℃, the system COP is about 0.65. The simulation results show that the dehumidification performances of the two solutions are very close under the same heat and mass transfer coefficient, and the COP of the mixed solution is slightly higher than that of the LiCl solution. At the driving temperature of 84℃, the outlet humidity of the mixed solution is about 6.0 g/kg, and the system COP is about 0.81. The higher the inlet humidity, the higher the system COP will be. Due to the lower specific heat capacity of the mixed solution, the heat consumption of the mixed solution in the regenerator is slightly lower, resulting in a slightly higher COP than that of the LiCl solution. In summary, the mixed solution of CaBr₂-CaCl₂=1∶1 can be a good substitute for LiCl solution in the liquid desiccant dehumidification system, which can achieve low cost and high performance.

Key words: liquid desiccant dehumidification, mixed solution, comparative study, numerical simulation, performance analysis

摘要：

对一种溶液除湿真空再生系统进行了实验及模拟研究，实验对比了LiCl溶液及CaBr₂∶CaCl₂=1∶1(溶质的质量分数比)混合溶液的系统性能，发现两溶液的出口含湿量及COP较为接近，当驱动温度为62℃时，系统COP均为0.65左右。通过模拟研究发现，两种溶液的除湿能力十分接近，混合溶液的COP略高于LiCl溶液。驱动温度84℃时，采用混合溶液的出口含湿量为6.0 g/kg左右，系统COP为0.81左右。进口含湿量越高，系统COP将会越高，得益于混合溶液较小的比热容，其再生溶液的耗热量略低，因此其COP略高于LiCl溶液。在此类溶液除湿系统中，CaBr₂∶CaCl₂=1∶1混合溶液能较好地替代LiCl溶液，实现低成本，高性能。

关键词: 溶液除湿, 混合溶液, 对比研究, 数值模拟, 性能分析

CLC Number:

TK 115

Xiaosong CHENG, Yonggao YIN, Chunwen CHE. Performance comparison of different working pairs on a liquid desiccant dehumidification system with vacuum regeneration[J]. CIESC Journal, 2023, 74(8): 3494-3501.

程小松, 殷勇高, 车春文. 不同工质在溶液除湿真空再生系统中的性能对比[J]. 化工学报, 2023, 74(8): 3494-3501.

Figures/Tables 10

References 20

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名称	类型	准确度	范围
温度计	T型热电偶	±0.1℃	-10~120℃
温湿度传感器	Vaisala HMT120	温度: ±0.1℃；湿度: ±1.5%	温度范围: -40~60℃；湿度范围:0~100%
空气流量计	KIMO CP300	±1 m³/h	0~9999 m³/h
电磁流量计	KQ-LDBF-15S-T2F1-000D	±0.5%	0.16~2.5 m³/h
电磁流量计	KQ-LDBF-15S-M2F1-001D	±0.5%	0.318~6 m³/h

名称	类型	准确度	范围
温度计	T型热电偶	±0.1℃	-10~120℃
温湿度传感器	Vaisala HMT120	温度: ±0.1℃；湿度: ±1.5%	温度范围: -40~60℃；湿度范围:0~100%
空气流量计	KIMO CP300	±1 m³/h	0~9999 m³/h
电磁流量计	KQ-LDBF-15S-T2F1-000D	±0.5%	0.16~2.5 m³/h
电磁流量计	KQ-LDBF-15S-M2F1-001D	±0.5%	0.318~6 m³/h

参数	数值
热水流量/（m³/h）	3.9
冷却水流量/（m³/h）	4.5
冷凝器冷却水进口温度/℃	27.5
除湿溶液流量/（m³/h）	3.6
再生溶液流量/（kg/s）	2
空气流量（混合溶液）/（m³/h）	2000
空气流量（LiCl溶液）/（m³/h）	2400
空气进口温度/℃	27~28
除湿溶液进口温度/℃	26~27
除湿再生循环流量/（kg/s）	0.3

参数	数值
热水流量/（m³/h）	3.9
冷却水流量/（m³/h）	4.5
冷凝器冷却水进口温度/℃	27.5
除湿溶液流量/（m³/h）	3.6
再生溶液流量/（kg/s）	2
空气流量（混合溶液）/（m³/h）	2000
空气流量（LiCl溶液）/（m³/h）	2400
空气进口温度/℃	27~28
除湿溶液进口温度/℃	26~27
除湿再生循环流量/（kg/s）	0.3

参数	数值
热水流量/（kg/s）	1
热水温度/℃	70
冷却水流量/（kg/s）	1.5
冷凝器冷却水进口温度/℃	33
除湿溶液流量/（kg/s）	0.8
除湿再生循环流量/（kg/s）	0.1
空气流量/（kg/s）	0.6
空气进口温度/℃	30
空气进口含湿量/（g/kg）	18
除湿溶液进口温度/℃	30
再生溶液流量/（kg/s）	1
溶液-溶液换热器效能	0.7