The Theoretical Research Of Thermal Stability Of Molten Salts Materials With Heat Transfer And Thermal Storage

Nowadays, energy has become a global issue. Clear and recyclable solar energy has become a trend to replace traditional fossil fuel energy. One of the key of improving the efficiency of solar thermal power generation is to choose the reliable high-temperature heat storage materials. As reliable heat transfer medium, molten nitrate salts have been widely used in various applications. In this paper, the reaction of molten nitrate salts oxidation has been studied. The reaction mechanism and adsorption of the ion of the reaction on (110) and (100) surface of the metal Cr have been discussed. The conclusions of this thesis may be refer to potential referable values for further theoretical and experimental studies of relevant study. The whole paper consists of five chapters, the specific research content and results are summarized as follows:1 In previous outstanding achievements, the summary of the molten nitrate salts under high temperature reactions may occur in 16 species by calculating the Gibbs free energy of these reactions and the reaction rate constant, infer the use of sodium nitrite in the molten salt temperature can occur response to the calculation of the fourth chapter provides a theoretical basis2 Quantum chemistry calculation methods using NO₂^- oxidation mechanism of the reactions. Use various methods to the reaction potential energy surface of reactants and products geometry optimized configuration, by comparison, established QCISD/6-311 + + G (d, p) method for the optimal method. Using this method the reaction potential energy surface of other stationary points were optimized geometries, has been the result of a transition state and one intermediate. Also through the intrinsic reaction coordinate (IRC) calculation and frequency analysis confirmed that the reaction of the transition state, and QCISD/6-311 + + G (d, p) level, accurate calculation of the reaction channel single-point stationary points able to confirm the reaction mechanism. The reaction barrier for the 94.0 kJ·mol^-1, is an exothermic reaction3 The Study based on first principles density functional theory, and NO₂^- plane model to study the metal Cr (110) plane and (100) top position in the adsorption. NO₂^- in the Cr (110) surface adsorption heat of 59.8 kJ·mol^-1, in Cr (100) surface adsorption heat of 59.5 kJ·mol^-1, NO₂^- in the Cr (110) surface than in the Cr (100) surface is adsorbed more stable. NO₂^- adsorption at the Cr atoms will contribute to catalytic reaction.