【作者】 倪海欧； 孙泽； 宋兴福； 于建国；

【Author】 Ze Sun;Xinmei Yang;haiou Ni;Xingfu Song;Jianguo Yu;East China University of Science and Technology,National Engineering Research Center for Integrated Utilization of Salt Lake Resources;

【机构】 华东理工大学国家盐湖资源综合利用工程技术研究中心；

【摘要】 能源问题是当今世界正面对的一大难题,而太阳能作为一种最廉价最清洁的能源,被人们认为是解决未来能源问题的一大方向。在太阳能利用领域,硝酸盐体系作为传蓄热介质应用最为广泛。硝酸盐在生产过程中会夹带部分杂质离子,其中以硫酸根和氯离子最为常见。为了研究这些杂质离子对熔融态硝酸盐结构的影响,本文以质量比1:1的KNO3/Na NO3混合盐为基础,向其中添加杂质离子(Cl-、SO2-4)。在保证K+/Na+质量比恒定不变的情况下,分别向混合物中添加了质量分数为x%的杂质离子,即Cl-或者SO2-:NO-43=x:(100-x)。对每一个熔盐配比,从常温到熔融态,测了其在不同温度和状态下的拉曼光谱和高温XRD图谱,来考察杂质离子对硝酸盐混合物的结构的影响。同时,为考察杂质离子对熔盐热物性和稳定性的影响,测量了混合熔盐的DSC数据。结合熔盐的热物性数据和结构信息,论文详细探讨了多种离子(K+、Na+、Cl-、SO2-4以及NO-3)在混合熔盐液态到固态过程中的竞争结合机理,从熔盐结构的角度分析了各种离子的结合顺序,并明晰了杂质离子对混合熔盐结构变化的影响。更多还原

【Abstract】 Nitrate based mixing salts were applied as heat transfer fluid and thermal energy storagemedia in commercial concentrated solar power(CSP) plants.Generally, the operating temperature of these salts is between 200 oC to 550 oC. There is a ternary nitrate combine with potassium nitrate, sodium nitrate and lithium nitrate. Different mass fraction(4%-20%) of sodium nitrite was added into this mixed nitrate. The peak position of lithium nitrate is similar to that of sodium nitrate and potassium nitrateby Raman spectrometer. And some of the peaks of the ternary nitrate can’t be accurately resolved. Raman spectra of mixed nitrate with different concentrations of sodium nitrite were observed. It is found that only when the content of sodium nitrite is high(20 wt%), the characteristic peaks of the sodium nitrite can be observed in the Raman spectra. And not only the ionic bond between cation and nitrate, but also the structure of nitrate was found changed. When the content of sodium nitrite is high(20 wt%), the characteristic peaks of the sodium nitrite can be observed in the Raman spectra. The ionic bond between potassium ion and nitrate and the structure of nitrate in potassium nitrate turn out a blue shift. While the ionic bond between sodium ion and nitrate and the structure of nitrate in sodium nitrate turn out a red shift. The start melting temperature and the thermal stability of this mixed nitrate changed with the content of sodium nitrite through a simultaneous thermal analyzer. The start melting temperature decreased with the increase of sodium nitrite(from 110oC to 104oC). And the quality loss under high temperature increased with the increase of sodium nitrite(from 1.87% to3.53%), which means the thermal stability decreased.更多还原