Quantum chemistry mechanism study on preventing slag‐bonding via modifying the material surface properties

Abstract

AbstractA huge amount of coal with high content of Na and K in ash was found in Xinjiang Province, China. However, the most serious ash fouling/slagging problems of that kind of coal usually cause the increasing of operating costs and energy consumption in a power plant. In order to clarify the mechanism of the effect on ash deposition behavior on different material surfaces, the experimental study, as well as quantum chemistry calculation, was used in this study. The results show that the nickel‐based material can significantly alleviate the ash deposition of high‐alkali coal. The adsorption energy between Na atom and NiO is much higher than that between Na atom and Fe2O3. The much lower system energy between Na atom and Fe2O3 will cause more stable system of Na‐Fe2O3. However, for nickel‐based material, the electrons of Na‐NiO system are being at a higher energy status, which will cause the system to stay at a relative unstable status. The quantum chemistry calculation results can well explain the phenomena of the experimental result. Furthermore, the interaction mechanisms between Na and Al‐based materials were also calculated to predict the effect of Al‐based material on preventing ash fouling and slagging. Copyright © 2016 Curtin University of Technology and John Wiley & Sons, Ltd.