PREPARATION AND THERMAL PROPERTY STUDY OF MIXED MOLTEN SALT WITH LOW MELTING POINT

摘要

Concentrating Solar Power (CSP) system is a large-scale,commercially viable way to generate electricity. The use of moltensalt heat transfer fluid (HTF) in a CSP system has several obviousadvantages. For instance, for a trough plant with salt, it may bepossible to raise the solar field output temperature to 450-500,thereby increasing the Rankine cycle efficiency of the power blocksteam turbine to the 40% range, compared to 393 with the currenthigh-temperature oil and a cycle efficiency of 37.6%. The HTFtemperature rise in the collector field can increase up to a factor of2.5, reducing the physical size of the thermal storage system for agiven capacity. Moreover, molten salt is cheaper and moreenvironmentally benign than the present HTF [1]. However, thedisadvantage of molten salt as heat transfer fluids is their relativelyhigh melting point, typically 140-240. The operational risk of afreeze-up if the process temperature drops unexpectedly adds cost tosystems that use salt as heat transfer fluids.