MgAl2O4 - SiC 내화물 복합체의 석탄 슬래그 침식 특성향상

Abstract

As progressing the depletion of petroleum resources, it has become a hot issue to develop novel power generation and syngas generation systems using coal. Integrated Gasification Combined Cycle(IGCC) is one of the cogeneration system using coal and also can make useful syngases. The essence of IGCC is a gasifier in which coal reacts with water in a partially oxidation and partially reduction atmosphere at a temperature range of 1300-1600℃. Because of the high reaction temperature of IGCC, refractories used inside of the gasifiers were attacked by molten coal slags. So refractories with high chromium oxide have been used for the gasifiers. Chromium is one of the restricted elements therefore development of chromium-free refractories which can resist molten coal slags at 1300-1600℃ is strongly demanded. In this study, MgAl2O4-SiC composite refractories bonded with alumina were developed. Content of coarse and fine MgAl2O4 and SiC particles were controlled to get dense refractories with high strength and resistivity to coal slags. The composite refractory with 25% coarse MgAl2O4 powder showed the highest bending and compressive strength of 23 and 134 MPa, respectively. and bonded Gamma alumina powder was used as and and the ecorrosion and spalling of the refractories were serious problems to solved. 's inside has eroded coal slag at high temperatures, we need refractories of heat-resisting property and strong erosion resistance at coal slag. Currently, it is commen for refraction of chromium at high percentages. But chromium refractories is one of high environment regulatory elements and volatility. That's why they need develop refractory of non chromium, heat-resisting property at high temperature of 1600 ℃, strong erosion resistance at coal slag. Bulk density, porosity, bending strength, compressive strength and resistance to coal slag were measured. Microstructure of the sintered refractories was analyzed using both optical and secondary electron microscopies and crystal phases were analyzed using XRD.