Performance Optimization Of Solar Thermal Power Molten Salt And Corrosion Behavior Of Several Materials In Molten Salt

Advantage of solar energy is that large reserves, widely distributed, non-polluting etc. In renewable energy, the solar thermal power generation is becoming the most promising way to produce electricity. Heat storage technology is one of the key solar thermal power generation. Nitrate molten salt is currently using more mature heat accumulating material salt. But disadvantages of Solar Two molten salt system is a high melting point, low thermal conductivity. And Hitec molten salt system occur decomposition of NaNO2, deterioration of molten salt, so its thermal stability become progressively worse. Therefore, the researcher find molten salt that has a low melting point, melting heat large, high specific heat capacity, low viscosity, good thermal stability. This research is has significance for solar thermal power.In this paper, Solar Two, Hitec molten salt system are modified by adjusting its components and adding additives. Their melting point, latent heat are measured by using of integrated thermal analyzer. Modified better additives and its dosage are selected. Then the Orthogonal that effect of good additives become orthogonal factors are designed. The experiment Comprehensively analyze the impact of various factors on the melting point, hot melt of the molten salt. Two optimum thermodynamic properties of a modified formulation of molten salt selected from the Solar Two, Hitec molten salt. The optimal formula of Solar Two molten salt system is 90%Solar Two+9%NaNO3+1%additive-C(Referred to as the optimum Solar Two molten salt), it melting point is 213.7℃ and latent heat is 106.11J/g. The optimal formula of Hitec molten salt system is 85%Hitec+10%NaNO3+2%NaNO2+1%additive-A+2%Additive-C(Referred to as the optimum Hitec molten salt), it melting point is 121.7℃ and latent heat is 68.11 J/g.The specific heat capacity, density, thermal conductivity, and viscosity of two optimum sought molten salts are respectively measured by the differential thermal analysis, archimedes method, laser flash method and spin column method. Thermal stability and storage/heat stability of two optimum sought molten salts is investigated. The density of two optimum sought molten salts is in the interests of good linear relationship. The viscosity of two optimum sought molten salts were about 1.8Cp.The viscosity almost reduced by an order of magnitude. Thermal conductivity of the best Solar Two molten salt is 0.556 / W ? m-1 ? K-1and thermal conductivity of the best Hitec molten salt is 0.405 / W ? m-1 ? K-1. After cycle 10 period, the solidification and melting temperature of two optimum sought molten salts remained almost unchanged. The thermal cycling performance of molten salts are good. Two optimum sought molten salts at high temperatures is small mass loss and their thermal stability is better.Finally, the corrosion kinetics of 304, 316 L, 321 H, P91, 12 CrMo metal material in two optimum sought molten salts at 500℃ is also investigated, and evaluate the corrosion resistance of stainless. 316 L, 304, 321 H stainless steel has good corrosion resistance, P91 steel have corrosion resistance follow by them, 12 CrMoVG have poor corrosion resistance. By SEM / EDS analysis shows, the corrosion products are mainly Fe oxide and Fe, Cr oxide.