Corrosion Resistant Refractory Ceramics for Slagging Gasifier Environment

Abstract

Integrated gasification combined cycle power systems are the most efficient and economical power generation systems with a relatively low environmental impact. the gasification process requires the optimal design of gasifiers with extremely corrosion resistant refractory lining. the majority of the refractory materials tested for gasifier lining applications cannot resist the action of slagging corrosive environment combined with high operation temperatures as high as 1600°C and possible thermal shocks and thermal expansion mismatch between the lining and the slag. Silicon carbide-based ceramics and some zirconia- and zircon-based ceramics manufactured by Ceramic Protection Corporation (CPC) have been tested in a simulated coal-fired slagging gasifier environment at a temperature of 1500°C. Crucible ceramic samples have been examined after exposure to the slag at high temperature. Microstructure studies of the ceramic zone contacted with the slag have been carried out. the highest performance, i.e. the absence of corrosion damage and thermal cracking after testing, was observed for silicon carbide-based ceramics ABSC formed by silicon carbide grains with an optimized particle size distribution bonded by the aluminosilicate crystalline-glassy matrix. Dense zirconia and alumina-zirconia and slightly porous zircon ceramics demonstrated comparatively lower performance due to their lower corrosion resistance and greater thermal cracking. ABSC ceramics can be manufactured as thick-walled large components and may be considered as a promising material for gasifier refractory applications. Similar ceramics, but with finer grain sizes, may also be recommended for thermocouple protection.