太阳能熔盐吸热器热防护特性研究

Research on thermal protection characteristics of solar molten salt receiver

针对外置式熔盐吸热器保温防护问题,搭建熔盐吸热器实验系统,通过调节氙灯模拟云遮工况,研究加装保温防护结构前后吸热器在辐射消失后的温降特性。发现采用6 cm厚硅酸铝保温棉作为防护材料,与吸热器表面间隔3 cm布置时,吸热器温度降低到熔盐凝固点附近的时间由120 s延长至560 s,运行操作时间增加3.5倍。通过增加保温防护结构可有效减缓云层遮挡后吸热器的温降速度,在熔盐凝固前争取更多操作时间,为我国多云气候特征下熔盐吸热器的安全运行提供借鉴。

Molten salt receiver is one of the core component of tower type solar plant, the conventional external system is exposed to air directly. When solar radiation is sheltered bu cloud, the temperature of the molten salt receiver drops sharply, which may caused the solidification of molten salt in the receiver and an accident if there is a fault operation. In the northwest of China, the solar energy resource is abundant, but cloud sheltering happenedfrequently, where thermal protection is more important for external molten salt receivers. A testing system of molten salt receiver was set up to study the temperature drop performance of molten salt receiver with/without thermal protection under cloudy conditions simulated by xenon-lamp. It was found that the time for solidification of molten salt could be prolonged from 120 seconds to 560 seconds, when a 6 cm aluminium silicate cover was placed nearby the molten salt receiver with a 3 cm space, and the operation time could increase by 3.5 times. It indicates that the increase of thermal protection can effectively slow down the temperature drop of the molten salt receiver after cloud cover, and gain more operation time before molten salt solidifies, which can provide reference for the safe operation of molten salt receiver under cloudy climate in China.