太阳能高温蓄热多元混合熔盐的制备和热性能的研究
发布时间：2018-08-02 12:31
【摘要】：能源作为我国经济和社会发展的重要组成部分。随着经济和技术的快速发展,我国能源消耗急剧增大,如煤、石油、天然气的大量开采和利用。在此同时又将导致大量温室气体的排放,对生态环境造成严重的危害。因此我国必须进行有效的能源结构调整,大力发展可再生能源,使其成为我国能源的发展重点。其中太阳能作为一种新型能源,具有资源丰富、受地域影响较小、清洁无污染等优点。太阳能热发电技术可以对太阳能进行很好地利用,而传热蓄热技术作为太阳能热发电技术的核心,选择合适的蓄热材料至关重要。熔盐作为蓄热材料具有使用温度高、粘度小、比热容高、成本低等优点,因此常被作为最好的蓄热材料。单独的氯化盐或者碳酸盐进行混合时,其相变温度及相变潜热较低,而使用氯化盐和碳酸盐两种盐类进行混合时,可以制备出相变温度和相变潜热相对较高的蓄热材料,更有利于应用于太阳能蓄热技术中。本文制备了氯化锂-氯化钠和氯化钠-碳酸钠两种二元混合熔盐以及氯化钾-碳酸钠-碳酸钾三元混合熔盐,利用差式扫描量热仪对混合熔盐的储热性能包括熔点、凝固点、潜热和热稳定性进行了实验研究。实验结果表明:可以发生共融的氯化锂-氯化钠混合熔盐的熔点为580℃左右,结晶潜热主要在200-400J/g之间;其中最佳配比为5:5,凝固温度为578.7℃,结晶潜热为320.2J/g;氯化锂-氯化钾的熔点为350℃左右,结晶潜热在60-200J/g之间;氯化钠-碳酸钠熔盐在600℃下未能发生共融;三元混合熔盐中可以发生共融的配比试样的熔点为570℃-580℃;凝固点主要集中在550℃-570℃之间;氯化钾:碳酸钠:碳酸钾=2:3:5的试样为最佳试样,具有较低的熔点568.9℃和凝固点545.3℃;熔盐的热稳定性较好。本文亦研究了混合熔盐的腐蚀性。对304和316L两种不锈钢片在静态下进行熔盐的腐蚀性实验分析,实验中使用的熔盐为NaCl-LiCl(50%-50%)、KCl-LiCl(50%-50%)、KCl-Na_2CO_3(50%-50%)、NaCl-Na_2CO_3(50%-50%)、KCl-K_2CO_3(50%-50%)、KCl-Na_2CO_3-K_2CO_3(30%-30%-40%)。结果显示:316L不锈钢片的抗腐蚀能力要强于304;相同总量,相同配比的碳酸熔盐和氯化熔盐相比,碳酸熔盐对两种不锈钢片的腐蚀性大于氯化盐。
[Abstract]:Energy as an important part of China's economic and social development. With the rapid development of economy and technology, China's energy consumption increases rapidly, such as coal, oil, natural gas exploitation and utilization. At the same time, it will lead to a large amount of greenhouse gas emissions, causing serious harm to the ecological environment. Therefore, our country must carry on the effective energy structure adjustment, vigorously develops the renewable energy, makes it become our country energy development focal point. As a new type of energy, solar energy has the advantages of rich resources, less influence by region, clean and pollution-free. Solar thermal power generation technology can make good use of solar energy, and heat transfer and heat storage technology is the core of solar thermal power generation technology, it is very important to select suitable heat storage materials. Molten salt as a heat storage material has the advantages of high temperature, low viscosity, high specific heat capacity, low cost and so on, so it is often used as the best heat storage material. The phase change temperature and latent heat of phase change are lower when the single salt or carbonate is mixed, but when the salt and carbonate are mixed, the heat storage material with higher phase change temperature and latent heat can be prepared. It is more favorable for the application of solar energy storage technology. In this paper, two binary mixed molten salts, lithium chloride sodium chloride and sodium chloride sodium carbonate, and ternary mixed molten salt of potassium chloride sodium carbonate and potassium carbonate have been prepared. The thermal storage performance of mixed molten salt by differential scanning calorimeter includes melting point and freezing point. Latent heat and thermal stability were studied experimentally. The experimental results show that the melting point of the mixture of lithium chloride and sodium chloride is about 580 鈩，
本文编号：2159446
[Abstract]:Energy as an important part of China's economic and social development. With the rapid development of economy and technology, China's energy consumption increases rapidly, such as coal, oil, natural gas exploitation and utilization. At the same time, it will lead to a large amount of greenhouse gas emissions, causing serious harm to the ecological environment. Therefore, our country must carry on the effective energy structure adjustment, vigorously develops the renewable energy, makes it become our country energy development focal point. As a new type of energy, solar energy has the advantages of rich resources, less influence by region, clean and pollution-free. Solar thermal power generation technology can make good use of solar energy, and heat transfer and heat storage technology is the core of solar thermal power generation technology, it is very important to select suitable heat storage materials. Molten salt as a heat storage material has the advantages of high temperature, low viscosity, high specific heat capacity, low cost and so on, so it is often used as the best heat storage material. The phase change temperature and latent heat of phase change are lower when the single salt or carbonate is mixed, but when the salt and carbonate are mixed, the heat storage material with higher phase change temperature and latent heat can be prepared. It is more favorable for the application of solar energy storage technology. In this paper, two binary mixed molten salts, lithium chloride sodium chloride and sodium chloride sodium carbonate, and ternary mixed molten salt of potassium chloride sodium carbonate and potassium carbonate have been prepared. The thermal storage performance of mixed molten salt by differential scanning calorimeter includes melting point and freezing point. Latent heat and thermal stability were studied experimentally. The experimental results show that the melting point of the mixture of lithium chloride and sodium chloride is about 580 鈩，
本文编号：2159446
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