多孔介质对相变材料吸附性能的实验研究

论文总字数：33943字

摘 要

相变材料(PCMs)通过储存和释放相变潜热一定程度上解决热量供需在时空上不匹配的矛盾，且其蓄能密度大、环保高效，已成为建筑节能研究的热点。为使PCMs在建筑领域中的有效应用，需利用多孔介质对其进行高效吸附储存。本文通过制备石蜡类复合相变材料对多孔介质的吸附性能和复合材料的热学性能进行研究，主要开展以下工作：

1. 影响吸附性能因素探究。通过控制吸附基体种类、吸附方法、吸附时间、基体粒径来研究多孔介质对吸附性能的影响，结果表明：吸附率与吸附时间呈正相关，吸附速率先快后慢，膨胀珍珠岩可在8h的吸附前满足蓄能要求；真空吸附法的吸附率优于直接浸渍法，膨胀珍珠岩真空吸附吸附率为自然吸附的2.61~5.90倍，陶粒则为1.10~1.86倍。随着时间的增长，陶粒的真空吸附相对直接浸渍的优势下降；粒径通过孔径对吸附性能产生影响，膨胀珍珠岩的直接浸渍中，吸附率上1~3mm组gt;0.85~2mm组gt;2~4mm组，在真空吸附24h中，吸附率与粒径呈正相关。在陶粒中，粒径对吸附性能无明显影响；膨胀石墨的吸附率是膨胀珍珠岩的5.0倍，是陶粒的25.3倍，膨胀珍珠岩的吸附率是陶粒的5.0~6.1倍。
2. 复合相变材料的热性能研究。通过对各材料中吸附性能最优的组别进行DSC测试，结果表明：石蜡/膨胀珍珠岩的相变温度为19.90℃，相变潜热为100.4J/g；石蜡/陶粒相变温度为20.28℃，相变潜热为43.03J/g；石蜡/膨胀石墨相变温度为19.83℃，相变潜热为120.77J/g。除石蜡/陶粒复合相变材料不能满足建筑蓄能材料60J/g的蓄能需求，其他两种复合相变材料皆满足蓄能需求，相变温度适宜，性能良好，可适用于建筑节能领域。

关键词：石蜡；多孔介质；吸附性能；热学性能

Abstract

The PCMs solve the contradiction between heat supply and demand in time and space through storage and release phase transformation, and their high energy storage density, environmental protection and high efficiency, which has become a hot spot in building energy conservation research. In order to effectively use PCMs in the construction field, it is necessary to use a porous medium for efficient adsorption storage. In this paper, the adsorption properties of porous media and the thermal properties of composites are studied by making paraffin composite phase change materials, The main work is as follows:

1. Factors affecting adsorption property. The effect of porous media on adsorption property was studied by controlling the type of adsorption matrix, adsorption method, adsorption time and matrix particle size. The results show that the adsorption property is positively correlated with the adsorption time, the adsorption rate is fast then slow, and the expanded perlite can be satisfied the energy storage requirement before 8 h adsorption; the adsorption rate of vacuum adsorption method is better than the direct mixing method, the vacuum adsorption adsorption rate of expanded perlite is 2.61~5.90 times of natural adsorption, and the ceramsite is 1.10~1.86 times. As time goes on, the adsorption rate between the two is getting smaller and smaller; the particle size affects the adsorption property through the pore size. In the direct mixing of expanded perlite, the adsorption rate is 1~3mm group gt;0.85~2mm groupgt;2~4mm. The adsorption rate was positively correlated with the particle size after the group was vacuum adsorbed for 24 h. In the ceramsite, the particle size has no significant effect on the adsorption property; the adsorption rate of expanded graphite is 5.0 times that of expanded perlite, 25.3 times that of ceramsite, and the adsorption rate of expanded perlite is 5.0 to 6.1 times that of ceramsite.

(2) Study on the thermal properties of composite phase change materials. The DSC test was carried out on the best adsorption property of each material. The results showed that the expansive perlite/paraffin phase transition temperature was 19.90 °C, the phase change latent heat was 100.4 J/g, and the ceramsite/paraffin phase transition temperature was 20.28 °C. The latent heat of phase change is 43.03 J/g; the phase transition temperature of expanded graphite/paraffin is 19.83 ° C, and the latent heat of phase change is 120.77 J/g. In addition to the ceramsite/paraffin composite phase change material can not meet the energy storage requirements(60J / g) of building energy storage materials, the other two composite phase change materials meet the energy storage demand, the phase transition temperature is suitable, the property is good, and it can be applied to the field of building energy conservation. .

KEY WORDS: paraffin; porous medium; adsorption property; Thermal property

目 录

摘 要 I

Abstract II

第一章 绪论 1

1.1 研究背景 1

1.2 研究目的和意义 1

1.3 相变材料的概述 2

1.3.1 相变材料的定义和分类 2

1.3.2 相变材料选择原则 3

1.3.3 相变材料的应用 3

1.4 多孔介质的概述 4

1.4.1 多孔介质的定义和吸附原理 4

1.4.2 多孔介质的选择 4

1.5 复合相变材料的制备方法 4

1.6 相变材料常用的性能测试方法 5

1.7 国内外研究现状 5

1.8 本论文研究内容 7

第二章 定形复合相变材料的制备和多孔介质的吸附性能研究 7

2.1引言 7

2.2试验原材料 8

2.2.1多孔介质选择 8

2.2.2相变材料选择 9

2.3试验设备 9

2.4定形石蜡基复合相变材料的制备 10

2.4.1膨胀珍珠岩对石蜡的吸附 10

2.4.2页岩陶粒对石蜡的吸附 12

2.4.3膨胀石墨对石蜡的吸附 13

2.5吸附性能试验结果与分析 14

2.5.1相变材料吸附量与吸附时间的关系 14

2.5.2相变材料吸附量与制备方法的关系 18

2.5.3相变材料吸附量与多孔介质粒径的关系 22

2.5.4相变材料吸附量与多孔介质材料的关系 26

2.6本章小结 27

第三章 定形复合相变材料的DSC测试 28

3.1 DSC测试方法 28

3.1.1 DSC测量系统介绍 28

3.1.2实验条件的影响及实验步骤： 29

3.2定型石蜡基复合相变材料的热物性分析 30

3.2.1纯石蜡的热物性 30

3.2.2理论相变潜热分析 33

3.3本章小结 34

第四章 结论与展望 34

4.1结论 34

4.2展望 35

参考文献： 36

致谢 38

第一章 绪论

研究背景

众所周知，能源是人类不可或缺的基本发展条件，能源问题也是影响国家发展的关键问题。我国是能源大国^[1]，据《BP集团能源统计年鉴》2017年中文版公布的数据显示，2016年我国原煤生产总量为240816万吨（标准煤），原油生产总量为28372万吨（标准煤），天然气生产总量18338万吨（标准煤），水电、核电、风电生产总量为58474万吨（标准煤）。同时，我国也是能源消费大国，2016年我国能源消费总量43.6亿吨标准煤，同比增速1.4%，煤炭的消费量下降4.7%，原油消费量增长5.5%，天然气增长8.0%，电力消费增长5.0%。我国已成为世界第二大能源消费国。近年来，能源需求随着经济发展和人口增长与日俱增，人均能源拥有量少，能源利用率不高，能源分布不均，产业结构不合理，环境污染严重，能源问题紧迫性进一步提高。

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