AGGLOMERATION OF ALUMINA SAND IN A FLUIDIZED-BED STRAW GASSIFIER AT ELEVATED-TEMPERATURES

The aim of this study was to investigate the agglomeration characteristics of alumina sand in a fluidized bed straw gasification system at various equivalence ratios (0.18, 0.21, 0.26, 0.34). The effect of ash content (0.0, 3.3, 27.8 and 43.5%) on the agglomeration of alumina sand was, also, investigated at various temperatures (620, 740 and 850-degrees-C) using a high temperature furnace. The results showed that agglomeration was affected by the ash content and temperature; the higher the ash content and/or the temperature the stronger was the bonding. It was, however, possible to operate the gasifier, without any agglomeration or slag problems, up to a temperature of 920-degrees-C. Although, this is higher than the temperature (800-degrees-C) at which silica sand was found to agglomerate, it is much lower than the fusion temperatures of the alumina sand (2000-degrees-C) and the straw ash (1054-degrees-C). It did, however, correspond to the initial deformation of wheat straw ash.