Name : [in Japanese]
Date : July 07, 2022 - July 08, 2022
Adhered ash in waste incineration facilities causes heat transfer inhibition, operational disturbances, and high-temperature corrosion. In particular, it is well known that molten salts with heavy metals have a significant impact on high-temperature corrosion. Thus, the objective of this study was to investigate the high-temperature corrosion behavior of Ni-based alloy with copper-added molten salts. The molten salt corrosion tests were performed by the simulated ash salt environment at 510 ℃ using an S/Cl ratio of 7.5 molten salt, NaCl-KCl-Na2SO4-K2SO4-CaSO4 systems, and the corrosion time variation of mass loss was investigated. The time variation of corrosion and the thickness variation of the corrosion scale indicates that the corrosion follows a parabolic rate law. The simulated ash salt was almost not melted under the test conditions, and the corrosion scale was porous, suggesting that the gas component corroded through these defects. Based on the thermodynamic calculations, the corrosion of molten salt containing Cu produced gas components, mainly sulfur oxidant and chloride, that affected the corrosion reaction compared with the corrosion without Cu addition. The XRD diffraction results showed the presence of NiCr2O4 in the corrosion scale, indicating the presence of Cr2O3 in the protective oxide film and the presence of NiO in the non-protective oxide film.
