Corrosion of high-chrome refractory materials by high-sodium slag in an entrained-flow gasifier

An entrained-flow gasifier is an efficient technology for converting coal-water slurry into syngas, however, high refractory wear by molten slag, especially basic slag, introduces challenges during industrial practice. Herein, the corroded macrostructure and microstructure of a high-chrome refractory by high-sodium slag in a commercial industrial opposed multi-burner gasifier were analyzed. The corrosion mechanism thereof was investigated by combining thermodynamic calculations. The results show that reaction and penetration layers were formed with the penetration of the slag. Complex spinel existed throughout the penetration path. Furthermore, EDS was performed for semi-quantitative analysis of the composition of the infiltrated slag, as a function of the penetration depth. The results indicated that the interaction between the high-chrome refractory and high-sodium slag could exist in the entire penetration path until the Fe and Mg elements were exhausted. The presence of Na changed the characteristics of the slag, promoting the penetration of slag into the refractory. However, the interaction between Na and the high-chrome refractory was very poor. Finally, the corrosion behavior of ZrO₂ grains in the refractory was investigated to understand the formation of a ZrO₂-less zone.