Corrosion of refractory materials in fluidised bed gasification of alkali rich fuels

Gasification of renewable fuels is not common practice due to the high costs of technologies and the absence of reliably working refractories. Refractory degradation is of such high significance that improved refractory durability was ranked first by industry experts in a list of 20 research and development areas related to the economic viability of gasification. Therefore, for improvement of the reliability and durability of refractory linings, this work is dealing with the corrosion resistance of nine commercial refractories to a variety of emissions from potential fuels. The refractories were exposed to a gasifier-like, water vapour and alkali rich atmosphere. Exposures with a duration of 250 h produced corrosion effects that were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. Furthermore, thermodynamic calculations were included to further explain the equilibrium chemistry. The results show that extremely low silica refractories are promising candidates for gasifier utilisation.