【摘要】：能源作為我國經(jīng)濟和社會發(fā)展的重要組成部分。隨著經(jīng)濟和技術(shù)的快速發(fā)展,我國能源消耗急劇增大,如煤、石油、天然氣的大量開采和利用。在此同時又將導致大量溫室氣體的排放,對生態(tài)環(huán)境造成嚴重的危害。因此我國必須進行有效的能源結(jié)構(gòu)調(diào)整,大力發(fā)展可再生能源,使其成為我國能源的發(fā)展重點。其中太陽能作為一種新型能源,具有資源豐富、受地域影響較小、清潔無污染等優(yōu)點。太陽能熱發(fā)電技術(shù)可以對太陽能進行很好地利用,而傳熱蓄熱技術(shù)作為太陽能熱發(fā)電技術(shù)的核心,選擇合適的蓄熱材料至關(guān)重要。熔鹽作為蓄熱材料具有使用溫度高、粘度小、比熱容高、成本低等優(yōu)點,因此常被作為最好的蓄熱材料。單獨的氯化鹽或者碳酸鹽進行混合時,其相變溫度及相變潛熱較低,而使用氯化鹽和碳酸鹽兩種鹽類進行混合時,可以制備出相變溫度和相變潛熱相對較高的蓄熱材料,更有利于應用于太陽能蓄熱技術(shù)中。本文制備了氯化鋰-氯化鈉和氯化鈉-碳酸鈉兩種二元混合熔鹽以及氯化鉀-碳酸鈉-碳酸鉀三元混合熔鹽,利用差式掃描量熱儀對混合熔鹽的儲熱性能包括熔點、凝固點、潛熱和熱穩(wěn)定性進行了實驗研究。實驗結(jié)果表明:可以發(fā)生共融的氯化鋰-氯化鈉混合熔鹽的熔點為580℃左右,結(jié)晶潛熱主要在200-400J/g之間;其中最佳配比為5:5,凝固溫度為578.7℃,結(jié)晶潛熱為320.2J/g;氯化鋰-氯化鉀的熔點為350℃左右,結(jié)晶潛熱在60-200J/g之間;氯化鈉-碳酸鈉熔鹽在600℃下未能發(fā)生共融;三元混合熔鹽中可以發(fā)生共融的配比試樣的熔點為570℃-580℃;凝固點主要集中在550℃-570℃之間;氯化鉀:碳酸鈉:碳酸鉀=2:3:5的試樣為最佳試樣,具有較低的熔點568.9℃和凝固點545.3℃;熔鹽的熱穩(wěn)定性較好。本文亦研究了混合熔鹽的腐蝕性。對304和316L兩種不銹鋼片在靜態(tài)下進行熔鹽的腐蝕性實驗分析,實驗中使用的熔鹽為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%)。結(jié)果顯示:316L不銹鋼片的抗腐蝕能力要強于304;相同總量,相同配比的碳酸熔鹽和氯化熔鹽相比,碳酸熔鹽對兩種不銹鋼片的腐蝕性大于氯化鹽。
[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，

本文編號：2159446