Experimental thermal performance study of molten salt steam generator-superheater with saturated water

Abstract

Molten salt steam generation is an important process in many high temperature thermal systems. In this paper, thermal performance of molten salt steam generator-superheater with saturated water was experimentally reported and analyzed. Experimental results showed that heat flow and thermal efficiency of evaporator were both significantly larger than those of superheater, and steam flow from evaporator influenced heat transfer of superheater, so evaporator dominated heat transfer performance of the whole system. In evaporator, boiling deterioration occurred with low water flow rate, while insufficient boiling appeared with high water flow rate, so inlet water flow rate should be increased properly to obtain suitable superheat and improve heat flow and thermal efficiency. Since heat losses of evaporator and superheater both increased with salt temperature/flow rate rising, their thermal efficiencies gradually dropped, while their effectiveness both increased with the increase of outlet temperature. Thermal resistance of superheater was about 6 times that of evaporator, and the thermal resistance of steam side in superheater accounted for more than 95% of its total thermal resistance. Therefore, heat transfer enhancement methods such as extended surface and spoiler technology should be adopted on steam side of superheater.