摘 要

在全球资源与环境问题日趋严峻的今天，随着太阳能开发利用技术的迅速发展，储热蓄热工质受到了愈加广泛的关注，提高储热材料性能是目前面临的重要课题。

本文采用NaNO₃：KNO₃=6:4质量比的混合硝酸盐为相变材料制备复合储热材料。无机盐相变材料在使用过程中需要有容器来盛装，相对于其他盐类来说，硝酸盐的腐蚀性较小。本文针对硝酸盐对容器的腐蚀性问题，采用蛭石进行吸附，制备了蛭石基复合相变材料，然后主要就复合相变材料对工业上常用且价格适中的310s不锈钢、304不锈钢、45碳钢、20碳钢等几种不同钢材的腐蚀性进行了探究。同时也对红铜、黄铜和铸铁等材料的抗硝酸盐腐蚀性能进行了尝试。经过长达960小时的腐蚀实验，每120小时取样后称取质量并记录。腐蚀后的金属材料通过金相测试、XRD物相分析和腐蚀动力学分析后，我们得出在硝酸盐和复合储热材料中310S不锈钢的耐腐蚀性均是最强的结论，其次是304不锈钢、45碳钢、20碳钢，蛭石吸附相变材料后对容器的腐蚀性明显减小。采用蛭石封装后能很好地降低相变材料对容器的腐蚀性。具体来说，310s和304不锈钢耐腐蚀性很好，X衍射分析没有检测到新物相的衍射峰，而45及20不锈钢腐蚀后有明显新相衍射峰的出现，表明45和20碳钢耐腐蚀性相比于310s和304较差，有较多的腐蚀产物生成。同时实验的另一部分尝试也得出在300℃时600h内发现黄铜和铸铁抗硝酸盐腐蚀性较强，而红铜较差的初步结论。

关键词：硝酸盐蓄热材料；容器材料；相容性；腐蚀

Abstract

Nowadays, the issue of global resources and environment becomes worse. With the rapid development of utilization technologies of solar energy, the working medium of heat storage is getting more attention. The significant issue we are facing is how to improve the properties of heat storage material.

This paper used mixed nitrate (NaNO₃：KNO₃=6:4) as the phase change material to research its compatibility with the container material. We needs a container while using the organic phase change material, and compared to other salts, nitrate is less corrosive. Thus, in the study of the inorganic salt corrosion towards the container, we used vermiculite as the adsorption and prepared the vermiculite-based composite phase change material. This paper chose several different steels that were commonly used in industry with fair price, such as 310s stainless steel, 304 stainless steel, 45 carbon steel and 20 carbon steel to study the causticity of nitrate heat storage material. And also made attempts to research the corrosion resistance copper, brass and cast iron. During the 960 hours of corrosion tests, we measured and recorded the quality of the metals per 120 hours. At last, the metallurgical test, XRD analysis and the dynamic analysis of corrosion showed that 310s stainless steel has the strongest resistance to corrosion, followed by 304 stainless steel, 45 carbon steel, 20 carbon steel. And the corrosion towards container was significantly decreased after vermiculite adsorbed the phase change material, which indicates that vermiculite package can prevent the corrosion of phase change material to containers. To be more specific, the corrosion resistance of 310s and 304 stainless steel were so good that there is no diffraction peaks of new phase detected in XRD. On the other hand, there are obvious new phase diffraction peak appeared in the XRD as for 45 and 20 carbon steel, which indicated there were many corrosion products generated and the corrosion resistance of 45 and 20 carbon steel is weaker than that of 310s and 304 stainless steel. And the study also shows the corrosion resistance towards nitrate of brass and cast iron is strong while that of copper is weak in the corrosion test at 300℃ within 600 hours.

Key words: Nitrate heat storage material；Container material；Compatibility；Corrosion

目 录

摘 要 I

Abstract II

第1章 绪论 1

1.1 引言 1

1.2 蓄热方式 1

1.2.1 显热蓄热 1

1.2.2 潜热蓄热 2

1.2.3 热化学反应蓄热 2

1.3 相变蓄热材料的分类 3

1.3.1 固-液相变蓄热材料 3

1.3.2 固-固相变蓄热材料 4

1.3.3 复合相变蓄热材料 5

1.4 相变蓄热材料的筛选原则 5

1.5 本文的研究目的、意义及内容 6

第2章 实验试剂与仪器 7

2.1 实验原料与试剂 7

2.2 实验仪器 7

2.3 结构表征与性能测试方法 8

2.3.1 物相分析 8

2.3.2 金相分析 8

第3章 NaNO₃-KNO₃/蛭石复合储热材料的制备及性能研究 9

3.1 混合硝酸盐的配制 9

3.2 结果与讨论 10

3.2.1 混合硝酸盐DSC 10

第4章 NaNO₃-KNO₃/蛭石复合储热材料对几种不锈钢的腐蚀性研究 11

4.1 实验部分 12

4.1.1 钢材的磨制 12

4.1.2 腐蚀实验具体操作方法： 13

4.2 结果与讨论 13

4.2.1 金相分析 13

4.2.2 腐蚀物相分析 16

4.2.3 腐蚀动力学分析 18

4.2.4 质量变化分析 20

第5章 结论与展望 22

参考文献 23

致 谢 25

第1章 绪论

1.1 引言

能源是人类社会发展的关键物质基础，对促进社会经济发展所起的作用举足轻重。改革开放以来，我国经济飞速发展，国内生产总值和能源消耗量迅速增长，促使我国已然经成为世界上第二大能源生产和消费国。同时，在经济规模的不断扩大和工业化进程的加快步伐中，能源短缺己成为限制经济发展的首要瓶颈。另一方面，我国以煤为主的能源结构和低效的能源利用，带来了如大气污染问题等严重的环境污染。长久下去，环境污染严重问题就会给我国经济可持续发展带来极大阻力。因此，大力发展能源科学技术，开发新能源，节约现有能源，降低能源消耗，提高能源利用率，是我们现阶段面临的重大课题。

能源科学技术中的一支重要分支被称为热能储存。在能源转换和利用中，常常存在供求之间在时间和空间上的矛盾，如太阳能、风能和海洋能的间隙性、电力负荷的峰谷差、工业窑炉的间断运行等等。因此，采用储能技术可以将富余能源储存起来，能源供应紧张时再利用，既可解决能源供求关系的矛盾，也同样是提高能源利用率的有效手段之一。